@article{rolston_hyman_semprini_2022, title={Single-well push-pull tests evaluating isobutane as a primary substrate for promoting in situ cometabolic biotransformation reactions}, volume={5}, DOI={10.1007/s10532-022-09987-w}, journal={BIODEGRADATION}, author={Rolston, Hannah and Hyman, Michael and Semprini, Lewis}, year={2022}, month={May} }
 @article{chen_faulkner_smith_fruchte_hyman_2021, title={Draft Genome Sequences of Four Aerobic Isobutane-Metabolizing Bacteria}, volume={5}, DOI={10.1128/MRA.01381-20}, journal={MICROBIOLOGY RESOURCE ANNOUNCEMENTS}, author={Chen, Weijue and Faulkner, Nicholas and Smith, Christy and Fruchte, Megan and Hyman, Michael}, year={2021}, month={May} }
 @article{murnane_chen_hyman_semprini_2021, title={Long-term cometabolic transformation of 1,1,1-trichloroethane and 1,4-dioxane by Rhodococcus rhodochrous ATCC 21198 grown on alcohols slowly produced by orthosilicates}, volume={6}, DOI={10.1016/j.jconhyd.2021.103796}, journal={JOURNAL OF CONTAMINANT HYDROLOGY}, author={Murnane, Riley A. and Chen, Weijue and Hyman, Michael and Semprini, Lewis}, year={2021}, month={Jun} }
 @article{rasmussen_saito_hyman_semprini_2020, title={Co-encapsulation of slow release compounds and Rhodococcus rhodochrous ATCC 21198 in gellan gum beads to promote the long-term aerobic cometabolic transformation of 1,1,1-trichloroethane, cis-1,2-dichloroethene and 1,4-dioxane}, DOI={10.1039/C9EM00607A}, journal={Environmental Science: Processes & Impacts}, publisher={Royal Society of Chemistry (RSC)}, author={Rasmussen, Mitchell T. and Saito, Alyssa M. and Hyman, Michael R. and Semprini, Lewis}, year={2020} }
 @article{mcelroy_hyman_knappe_2019, title={1,4-Dioxane in drinking water: Emerging for forty years and still unregulated}, volume={1}, ISSN={2468-5844}, url={http://www.sciencedirect.com/science/article/pii/S2468584418300485}, DOI={10.1016/j.coesh.2019.01.003}, abstractNote={The likely human carcinogen 1,4-dioxane was first detected in drinking water more than 40 years ago, and a recent analysis suggests that almost 30 million people in the United States receive drinking water with 1,4-dioxane levels above the health-based reference concentration of 0.35 μg/L. The widespread occurrence of 1,4-dioxane has exposed the need for developing and implementing management and treatment approaches that protect drinking water sources and prevent human exposure to 1,4-dioxane through drinking water. In this review we highlight recent advances in analytical methods, understanding of occurrence, and treatment processes. Finding are discussed in the context of managing 1,4-dioxane as a drinking water contaminant, and recommendations are made to address important knowledge gaps.}, journal={Current Opinion in Environmental Science & Health}, author={McElroy, Amie C. and Hyman, Michael R. and Knappe, Detlef R. U.}, year={2019}, month={Jan} }
 @article{rolston_hyman_semprini_2019, title={Aerobic cometabolism of 1,4-dioxane by isobutane-utilizing microorganisms including Rhodococcus rhodochrous strain 21198 in aquifer microcosms: Experimental and modeling study}, volume={694}, ISBN={1879-1026}, DOI={10.1016/j.scitotenv.2019.133688}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Rolston, Hannah M. and Hyman, Michael R. and Semprini, Lewis}, year={2019} }
 @article{ortiz-medina_grunden_hyman_call_2019, title={Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells}, volume={1}, url={https://doi.org/10.1021/acssuschemeng.8b05763}, DOI={10.1021/acssuschemeng.8b05763}, abstractNote={Ammonia (NH3) is an important industrial chemical that is produced using the energy- and carbon-intensive Haber-Bosch process. Recovering NH3 from microorganisms that fix nitrogen gas (N2) may provide a sustainable alternative because their specialized nitrogenase enzymes can reduce N2 to ammonium (NH4+) without the need for high temperature and pressure. This study explored the possibility of converting N2 into NH4+ using anaerobic, single-chamber microbial electrolysis cells (MECs). N2 fixation rates [based on an acetylene gas (C2H2) to ethylene gas (C2H4) conversion assay] of a microbial consortium increased significantly when the applied voltage between the anode and cathode increased from 0.7 to 1.0 V and reached a maximum of ∼40 nmol of C2H4 min–1 mg protein–1, which is comparable to model aerobic N2-fixing bacteria. The presence of NH4+, which can inhibit the activity of the nitrogenase enzyme, did not significantly reduce N2 fixation rates. Upon addition of methionine sulfoximine, an NH4+ uptake inhibitor, NH4+ was recovered at rates approaching 5.2 × 10–12 mol of NH4+ s–1 cm–2 (normalized to the anode surface area). Relative to the electrical energy consumed, the normalized energy demand [MJ mol–1 (NH4+)] was negative because of the energy-rich methane gas recovered in the MEC. Including the substrate energy resulted in total energy demands as low as 24 MJ mol–1. Community analysis results of the anode biofilms revealed that Geobacter species predominated in both the presence and absence of NH4+, suggesting that they played a key role in current generation and N2 fixation. This study shows that MECs may provide a new route for generating NH4+.}, journal={ACS Sustainable Chemistry & Engineering}, author={Ortiz-Medina, Juan F. and Grunden, Amy M. and Hyman, Michael R. and Call, Douglas F.}, year={2019}, month={Jan} }
 @inbook{biodegradation of ether pollutants_2018, DOI={10.1007/978-3-319-44535-9}, booktitle={Consequences of Microbial Interactions with Hydrocarbons, Oils, and Lipids: Biodegradation and Bioremediation}, year={2018} }
 @article{chu_bennett_dolan_hyman_peacock_bodour_anderson_mackay_goltz_2018, title={Concurrent Treatment of 1,4-Dioxane and Chlorinated Aliphatics in a Groundwater Recirculation System Via Aerobic Cometabolism}, volume={38}, ISSN={1745-6592}, url={https://onlinelibrary.wiley.com/doi/abs/10.1111/gwmr.12293}, DOI={10.1111/gwmr.12293}, abstractNote={This research demonstrates that groundwater contaminated by a relatively dilute but persistent concentration of 1,4-dioxane (1,4-D), approximately 60 μg/L, and chlorinated aliphatic co-contaminants (1.4 to 10 μg/L) can be efficiently and reliably treated by in situ aerobic cometabolic biodegradation (ACB). A field trial lasting 265 days was conducted at Operable Unit D at the former McClellan Air Force Base and involved establishing an in situ ACB reactor through amending recirculated groundwater with propane and oxygen. The stimulated indigenous microbial population was able to consistently degrade 1,4-D to below 3 μg/L while the co-contaminants trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA) were decreased to below 1 μg/L and 0.18 μg/L, respectively. A stable treatment efficiency of more than 95% removal for 1,4-D and 1,2-DCA and of more than 90% removal for TCE was achieved. High treatment efficiencies for 1,4-D and all co-contaminants were sustained even without propane and oxygen addition for a 2-week period.}, number={3}, journal={Groundwater Monitoring & Remediation}, author={Chu, Min-Ying Jacob and Bennett, Peter J. and Dolan, Mark E. and Hyman, Michael R. and Peacock, Aaron D. and Bodour, Adria and Anderson, Richard Hunter and Mackay, Douglas M. and Goltz, Mark N.}, year={2018}, pages={53–64} }
 @article{bennett_hyman_smith_el mugammar_chu_nickelsen_aravena_2018, title={Enrichment with Carbon-13 and Deuterium during Monooxygenase-Mediated Biodegradation of 1,4-Dioxane}, volume={5}, url={https://doi.org/10.1021/acs.estlett.7b00565}, DOI={10.1021/acs.estlett.7b00565}, abstractNote={Recent technical developments have enabled the application of compound-specific isotope analysis (CSIA) of low (parts per billion) concentrations of 1,4-dioxane that are often found in groundwater at 1,4-dioxane-contaminated sites. However, to quantify 1,4-dioxane biodegradation, isotopic enrichment factors are needed to interpret the CSIA data obtained from field samples. In this study, the carbon and hydrogen isotopic enrichment factors (εC and εH, respectively) for 1,4-dioxane biodegradation have been determined for axenic propane- or isobutane-grown cultures of Rhodococcus rhodochrous ATCC 21198 and for tetrahydrofuran-grown cultures of Pseudonocardia tetrahydrofuranoxidans K1. The enrichment factors for propane-grown (εC = −2.7 ± 0.3‰, and εH = −21 ± 2‰) and isobutane-grown (εC = −2.5 ± 0.3‰, and εH = −28 ± 6‰) cells of strain 21198 were similar and substantially smaller than those determined for tetrahydrofuran-grown cells of strain K1 (εC = −4.7 ± 0.9‰, and εH = −147 ± 22‰). The presence of 1-butyne consistently inhibited both the biodegradation and isotopic fractionation of 1,4-dioxane, and this effect implicates monooxygenase enzymes in both the biodegradation and isotopic enrichment of 1,4-dioxane. Our results confirm that an increasing level of enrichment of heavier isotopes of carbon and hydrogen can be used to quantify 1,4-dioxane biodegradation and suggest CSIA can discriminate between the activities of monooxygenase-expressing bacteria expected to be prevalent in engineered, gaseous alkane-stimulated 1,4-dioxane treatment systems and those that may involve microbial metabolism of 1,4-dioxane as a natural attenuation process.}, number={3}, journal={Environmental Science & Technology Letters}, author={Bennett, Peter and Hyman, Michael and Smith, Christy and El Mugammar, Humam and Chu, Min-Ying and Nickelsen, Michael and Aravena, Ramon}, year={2018}, month={Mar}, pages={148–153} }
 @article{bennett_sadler_wright_yeager_hyman_2016, title={Activity-Based Protein Profiling of Ammonia Monooxygenase in Nitrosomonas europaea}, volume={82}, ISSN={0099-2240, 1098-5336}, url={https://aem.asm.org/content/82/8/2270}, DOI={10.1128/aem.03556-15}, abstractNote={Nitrosomonas europaea is an aerobic nitrifying bacterium that oxidizes ammonia (NH3) to nitrite (NO2 −) through the sequential activities of ammonia monooxygenase (AMO) and hydroxylamine dehydrogenase (HAO). Many alkynes are mechanism-based inactivators of AMO, and here we describe an activity-based protein profiling method for this enzyme using 1,7-octadiyne (17OD) as a probe. Inactivation of NH4 +-dependent O2 uptake by N. europaea by 17OD was time- and concentration-dependent. The effects of 17OD were specific for ammonia-oxidizing activity, and de novo protein synthesis was required to reestablish this activity after cells were exposed to 17OD. Cells were reacted with Alexa Fluor 647 azide using a copper-catalyzed azide-alkyne cycloaddition (CuAAC) (click) reaction, solubilized, and analyzed by SDS-PAGE and infrared (IR) scanning. A fluorescent 28-kDa polypeptide was observed for cells previously exposed to 17OD but not for cells treated with either allylthiourea or acetylene prior to exposure to 17OD or for cells not previously exposed to 17OD. The fluorescent polypeptide was membrane associated and aggregated when heated with β-mercaptoethanol and SDS. The fluorescent polypeptide was also detected in cells pretreated with other diynes, but not in cells pretreated with structural homologs containing a single ethynyl functional group. The membrane fraction from 17OD-treated cells was conjugated with biotin-azide and solubilized in SDS. Streptavidin affinity-purified polypeptides were on-bead trypsin-digested, and amino acid sequences of the peptide fragments were determined by liquid chromatography-mass spectrometry (LC-MS) analysis. Peptide fragments from AmoA were the predominant peptides detected in 17OD-treated samples. In-gel digestion and matrix-assisted laser desorption ionization–tandem time of flight (MALDI-TOF/TOF) analyses also confirmed that the fluorescent 28-kDa polypeptide was AmoA.}, number={8}, journal={Appl. Environ. Microbiol.}, author={Bennett, Kristen and Sadler, Natalie C. and Wright, Aaron T. and Yeager, Chris and Hyman, Michael R.}, year={2016}, month={Apr}, pages={2270–2279} }
 @inbook{aerobic degradation of gasoline ether oxygenates_2016, DOI={10.1007/978-3-319-39782-5_16-1}, booktitle={Aerobic Utilization of Hydrocarbons, Oils and Lipids}, year={2016} }
 @article{kottegoda_waligora_hyman_2015, title={Isolation and characterization of a 2-methylpropene (isobutylene)-metabolizing bacterium, Mycobacterium sp. ELW1}, volume={81}, journal={Applied and Environmental Microbiology}, author={Kottegoda, S. and Waligora, E. and Hyman, M.}, year={2015}, pages={1966–1976} }
 @article{kottegoda_waligora_hyman_2015, title={Metabolism of 2-methylpropene (isobutylene) by the aerobic bacterium mycobacterium sp strain ELW1}, volume={81}, DOI={10.1128/aem.03103-14}, number={6}, journal={Applied and Environmental Microbiology}, author={Kottegoda, S. and Waligora, E. and Hyman, Michael}, year={2015}, pages={1966–1976} }
 @article{trippe_wolpert_hyman_ciuffetti_2014, title={RNAi silencing of a cytochrome P450 monoxygenase disrupts the ability of a filamentous fungus, Graphium sp., to grow on short-chain gaseous alkanes and ethers}, volume={25}, ISSN={1572-9729}, DOI={10.1007/s10532-013-9646-1}, abstractNote={Graphium sp. (ATCC 58400), a filamentous fungus, is one of the few eukaryotes that grows on short-chain alkanes and ethers. In this study, we investigated the genetic underpinnings that enable this fungus to catalyze the first step in the alkane and ether oxidation pathway. A gene, CYP52L1, was identified, cloned and functionally characterized as an alkane-oxidizing cytochrome P450 (GSPALK1). Analysis of CYP52L1 suggests that it is a member of the CYP52 cytochrome P450 family, which is comprised of medium- and long-chain alkane-oxidizing enzymes found in yeasts. However, phylogenetic analysis of GSPALK1 with other CYP52 members suggests they are not closely related. Post-transcriptional ds-RNA-mediated gene silencing of CYP52L1 severely reduced the ability of this fungus to oxidize alkanes and ethers, however, downstream metabolic steps in these pathways were unaffected. Collectively, the results of this study suggest that GSPALK1 is the enzyme that catalyzes the initial oxidation of alkanes and ethers but is not involved in the later steps of alkane or ether metabolism.}, number={1}, journal={Biodegradation}, author={Trippe, Kristin M. and Wolpert, Thomas J. and Hyman, Michael R. and Ciuffetti, Lynda M.}, year={2014}, month={Feb}, pages={137–151} }
 @article{hyman_2013, title={Biodegradation of gasoline ether oxygenates}, volume={24}, ISSN={1879-0429}, DOI={10.1016/j.copbio.2012.10.005}, abstractNote={Ether oxygenates such as methyl tertiary butyl ether (MTBE) are added to gasoline to improve fuel combustion and decrease exhaust emissions. Ether oxygenates and their tertiary alcohol metabolites are now an important group of groundwater pollutants. This review highlights recent advances in our understanding of the microorganisms, enzymes and pathways involved in both the aerobic and anaerobic biodegradation of these compounds. This review also aims to illustrate how these microbiological and biochemical studies have guided, and have helped refine, molecular and stable isotope-based analytical approaches that are increasingly being used to detect and quantify biodegradation of these compounds in contaminated environments.}, number={3}, journal={Current Opinion in Biotechnology}, author={Hyman, Michael}, year={2013}, month={Jun}, pages={443–450} }
 @article{lan_smith_hyman_2013, title={Oxidation of Cyclic Ethers by Alkane-Grown Mycobacterium vaccae JOB5}, volume={23}, ISSN={1520-6831}, url={https://onlinelibrary.wiley.com/doi/abs/10.1002/rem.21364}, DOI={10.1002/rem.21364}, abstractNote={In this study we investigated the cometabolic oxidation of six cyclic ethers by alkane-grown Mycobacterium vaccae JOB5. These ethers include, among others, tetrahydrofuran (THF), 1,4-dioxane (14D), 1,3-dioxolane (13DO), and tetrahydropyran (THP). Cells grown on propane, n-butane, n-pentane, isobutane, or isopentane oxidized all six ethers. Ether-degrading activity was inhibited by acetylene in alkane-grown cells and was largely absent from cells grown on dextrose-containing media. Propane competitively inhibited THF oxidation. γ-Butyrolactone (γBL) accumulated and was also further oxidized during THF oxidation by propane-grown cells. In contrast, no products were detected during 14D oxidation. Propane-grown cells also rapidly oxidized 3-hydroxytertrahydrofuran and exhibited strong hemiacetal-oxidizing activity in an assay following methyl formate production from mixtures of methanol and formaldehyde. These observations suggest γBL is likely generated during THF oxidation through further oxidation of 2-hydroxytetrahydrofuran. Limited growth of strain JOB5 was supported by several cyclic ethers and the corresponding lactones and diols potentially derived from these compounds. However, strain JOB5 grew more readily on 4-hydroxybutyrate, the product of γBL hydrolysis. The ability of strain JOB5 to productively assimilate THF-derived metabolites during growth on n-alkanes was examined in carbon-limited batch cultures. Relative to C-limited growth on n-pentane alone, culture growth increased up to twofold in the presence of THF while no stimulation of growth was observed in comparable experiments conducted with n-pentane and 14D. Our results are discussed in terms of their significance to our understanding of cyclic ether cometabolism and their potential impact on approaches for cyclic ether biodegradation in the environment. © 2013 Wiley Periodicals, Inc.}, number={4}, journal={Remediation Journal}, author={Lan, Renny S. and Smith, Christy A. and Hyman, Michael R.}, year={2013}, pages={23–42} }
 @article{hamilton_luginbuhl_hyman_2012, title={Preparing Science-Trained Professionals for the Biotechnology Industry: A Ten-Year Perspective on a Professional Science Master’s Program}, volume={13}, ISSN={1935-7877}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577309/}, DOI={10.1128/jmbe.v13i1.375}, abstractNote={The biotechnology industry has a need for business-savvy scientists; however, this is not the way scientists are traditionally trained at universities and colleges. To address this need, universities have developed Professional Science Master’s (PSM) degree programs that offer advanced training in a technical field along with professional skills development through team-based projects and internships. Nearly ten years ago, the Department of Microbiology at NCSU started a PSM program in Microbial Biotechnology (MMB). This article provides an overview of the MMB program, and shares some of the lessons that we have learned.}, number={1}, journal={Journal of Microbiology & Biology Education : JMBE}, author={Hamilton, Paul T. and Luginbuhl, Sarah C. and Hyman, Michael}, year={2012}, month={May}, pages={39–44} }
 @article{aslett_haas_hyman_2011, title={Identification of tertiary butyl alcohol (TBA)-utilizing organisms in BioGAC reactors using 13C-DNA stable isotope probing}, volume={22}, ISSN={1572-9729}, DOI={10.1007/s10532-011-9455-3}, abstractNote={Biodegradation of the gasoline oxygenates methyl tertiary-butyl ether (MTBE) and ethyl tertiary-butyl ether (ETBE) can cause tertiary butyl alcohol (TBA) to accumulate in gasoline-impacted environments. One remediation option for TBA-contaminated groundwater involves oxygenated granulated activated carbon (GAC) reactors that have been self-inoculated by indigenous TBA-degrading microorganisms in ground water extracted from contaminated aquifers. Identification of these organisms is important for understanding the range of TBA-metabolizing organisms in nature and for determining whether self-inoculation of similar reactors is likely to occur at other sites. In this study (13)C-DNA-stable isotope probing (SIP) was used to identify TBA-utilizing organisms in samples of self-inoculated BioGAC reactors operated at sites in New York and California. Based on 16S rRNA nucleotide sequences, all TBA-utilizing organisms identified were members of the Burkholderiales order of the β-proteobacteria. Organisms similar to Cupriavidus and Methylibium were observed in both reactor samples while organisms similar to Polaromonas and Rhodoferax were unique to the reactor sample from New York. Organisms similar to Hydrogenophaga and Paucibacter strains were only detected in the reactor sample from California. We also analyzed our samples for the presence of several genes previously implicated in TBA oxidation by pure cultures of bacteria. Genes Mpe_B0532, B0541, B0555, and B0561 were all detected in (13)C-metagenomic DNA from both reactors and deduced amino acid sequences suggested these genes all encode highly conserved enzymes. One gene (Mpe_B0555) encodes a putative phthalate dioxygenase-like enzyme that may be particularly appropriate for determining the potential for TBA oxidation in contaminated environmental samples.}, number={5}, journal={Biodegradation}, author={Aslett, Denise and Haas, Joseph and Hyman, Michael}, year={2011}, month={Sep}, pages={961–972} }
 @article{house_hyman_2010, title={Effects of gasoline components on MTBE and TBA cometabolism by Mycobacterium austroafricanum JOB5}, volume={21}, ISSN={1572-9729}, DOI={10.1007/s10532-009-9321-8}, abstractNote={In this study we have examined the effects of individual gasoline hydrocarbons (C(5-10,12,14) n-alkanes, C(5-8) isoalkanes, alicyclics [cyclopentane and methylcyclopentane] and BTEX compounds [benzene, toluene, ethylbenzene, m-, o-, and p-xylene]) on cometabolism of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (TBA) by Mycobacterium austroafricanum JOB5. All of the alkanes tested supported growth and both MTBE and TBA oxidation. Growth on C(5-8) n-alkanes and isoalkanes was inhibited by acetylene whereas growth on longer chain n-alkanes was largely unaffected by this gas. However, oxidation of both MTBE and TBA by resting cells was consistently inhibited by acetylene, irrespective of the alkane used as growth-supporting substrate. A model involving two separate but co-expressed alkane-oxidizing enzyme systems is proposed to account for these observations. Cyclopentane, methylcyclopentane, benzene and ethylbenzene did not support growth but these compounds all inhibited MTBE and TBA oxidation by alkane-grown cells. In the case of benzene, the inhibition was shown to be due to competitive interactions with both MTBE and TBA. Several aromatic compounds (p-xylene > toluene > m-xylene) did support growth and cells previously grown on these substrates also oxidized MTBE and TBA. Low concentrations of toluene (<10 microM) stimulated MTBE and TBA oxidation by alkane-grown cells whereas higher concentrations were inhibitory. The effects of acetylene suggest strain JOB5 also has two distinct toluene-oxidizing activities. These results have been discussed in terms of their impact on our understanding of MTBE and TBA cometabolism and the enzymes involved in these processes in mycobacteria and other bacteria.}, number={4}, journal={Biodegradation}, author={House, Alan J. and Hyman, Michael R.}, year={2010}, month={Jul}, pages={525–541} }
 @article{smith_hyman_2010, title={Oxidation of gasoline oxygenates by closely related non-haem-iron alkane hydroxylases in Pseudomonas mendocina KR1 and other n-octane-utilizing Pseudomonas strains}, volume={2}, ISSN={1758-2229}, DOI={10.1111/j.1758-2229.2010.00155.x}, abstractNote={Pseudomonas mendocina KR1 oxidizes the gasoline oxygenate methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) during growth on C5 -C8 n-alkanes. We have further explored oxidation of ether oxygenates by this strain to help identify the enzyme that catalyses these reactions. High levels of MTBE-oxidizing activity occurred in resting cells grown on C5 -C8 n-alkanes. Lower activities occurred in cells grown on longer-chain n-alkanes (C9 -C11 ) and 1°-alcohols (C5 -C10 ). N-octane-grown cells also oxidized tertiary amyl methyl ether (TAME) to tertiary amyl alcohol (TAA), but did not oxidize ethyl tertiary butyl ether (ETBE), TBA or TAA. A 39 kDa polypeptide in whole cell extracts of n-octane-grown cells strongly cross-reacted with an anti-AlkB polyclonal antiserum in an SDS-PAGE/immunoblot. This polypeptide was absent or less abundant in cells grown on dextrose, dextrose plus dicyclopropylketone or 1-octanol. N-octane-grown cells of Pseudomonas aeruginosa strains KSLA-473 and ATCC 17423 oxidized MTBE and TAME but not ETBE. N-hexadecane-grown cells of these strains and strain PAO1 did not oxidize any of the oxygenates tested. Our results indicate ether oxygenate-degrading activity in alkane-utilizing pseudomonads is consistently observed with close homologues of the GPo1 non-haem-iron alkane hydroxylases but is otherwise not a consistent catalytic feature of these diverse enzymes.}, number={3}, journal={Environmental Microbiology Reports}, author={Smith, Christy A. and Hyman, Michael R.}, year={2010}, month={Jun}, pages={426–432} }
 @article{oxidation of gasoline oxygenates by closely related non-haem-iron alkane hydroxylases in pseudomonas mendocina kr1 and other n-octane-utilizing pseudomonas strains._2010, DOI={10.1111/j.1758-2229.2010.00155.x}, journal={Environmental microbiology reports}, year={2010}, month={Mar} }
 @article{lee_m_2009, title={Helping educational reforms to succeed in a Microbiology Department}, volume={4}, journal={Microbe}, author={Lee, V.S. and M, Hyman}, year={2009}, pages={219–223} }
 @article{mckelvie_hyman_elsner_smith_aslett_lacrampe-couloume_sherwood lollar_2009, title={Isotopic Fractionation of Methyl tert-Butyl Ether Suggests Different Initial Reaction Mechanisms during Aerobic Biodegradation}, volume={43}, ISSN={0013-936X}, url={https://doi.org/10.1021/es803307y}, DOI={10.1021/es803307y}, abstractNote={Carbon isotopic enrichment factors (εC) measured during cometabolic biodegradation of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) by Pseudonocardia tetrahydrofuranoxydans strain K1 were −2.3 ± 0.2‰, −1.7 ± 0.2‰, and −1.7 ± 0.3‰, respectively. The measured carbon apparent kinetic isotope effect was 1.01 for all compounds, consistent with the expected kinetic isotope effects for both oxidation of the methoxy (or ethoxy) group and enzymatic SN1 biodegradation mechanisms. Significantly, δ13C measurements of the tert-butyl alcohol and tert-amyl alcohol products indicated that the tert-butyl and tert-amyl groups do not participate in the reaction and confirmed that ether biodegradation by strain K1 involves oxidation of the methoxy (or ethoxy) group. Measured hydrogen isotopic enrichment factors (εH) were −100 ± 10‰, −73 ± 7‰, and −72 ± 2‰ for MTBE, ETBE, and TAME respectively. Previous results reported for aerobic biodegradation of MTBE by Methylibium petroleiphilum PM1 and Methylibium R8 showed smaller εH values (−35‰ and −42‰, respectively). Plots of Δ2H/ Δ13C show different slopes for strain K1 compared with strains PM1 and R8, suggesting that different mechanisms are utilized by K1 and PM1/R8 during aerobic MTBE biodegradation.}, number={8}, journal={Environmental Science & Technology}, author={McKelvie, Jennifer R. and Hyman, Michael R. and Elsner, Martin and Smith, Christy and Aslett, Denise M. and Lacrampe-Couloume, Georges and Sherwood Lollar, Barbara}, year={2009}, month={Apr}, pages={2793–2799} }
 @article{skinner_cuiffetti_hyman_2009, title={Metabolism and Cometabolism of Cyclic Ethers by a Filamentous Fungus, a Graphium sp.}, volume={75}, ISSN={0099-2240, 1098-5336}, url={https://aem.asm.org/content/75/17/5514}, DOI={10.1128/AEM.00078-09}, abstractNote={The filamentous fungus Graphium sp. (ATCC 58400) grows on gaseous n-alkanes and diethyl ether. n-Alkane-grown mycelia of this strain also cometabolically oxidize the gasoline oxygenate methyl tert-butyl ether (MTBE). In this study, we characterized the ability of this fungus to metabolize and cometabolize a range of cyclic ethers, including tetrahydrofuran (THF) and 1,4-dioxane (14D). This strain grew on THF and other cyclic ethers, including tetrahydropyran and hexamethylene oxide. However, more vigorous growth was consistently observed on the lactones and terminal diols potentially derived from these ethers. Unlike the case in all previous studies of microbial THF oxidation, a metabolite, γ-butyrolactone, was observed during growth of this fungus on THF. Growth on THF was inhibited by the same n-alkenes and n-alkynes that inhibit growth of this fungus on n-alkanes, while growth on γ-butyrolactone or succinate was unaffected by these inhibitors. Propane and THF also behaved as mutually competitive substrates, and propane-grown mycelia immediately oxidized THF, without a lag phase. Mycelia grown on propane or THF exhibited comparable high levels of hemiacetal-oxidizing activity that generated methyl formate from mixtures of formaldehyde and methanol. Collectively, these observations suggest that THF and n-alkanes may initially be oxidized by the same monooxygenase and that further transformation of THF-derived metabolites involves the activity of one or more alcohol dehydrogenases. Both propane- and THF-grown mycelia also slowly cometabolically oxidized 14D, although unlike THF oxidation, this reaction was not sustainable. Specific rates of THF, 14D, and MTBE degradation were very similar in THF- and propane-grown mycelia.}, number={17}, journal={Appl. Environ. Microbiol.}, author={Skinner, Kristin and Cuiffetti, Lynda and Hyman, Michael}, year={2009}, month={Sep}, pages={5514–5522} }
 @article{skinner_martinez-prado_hyman_williamson_ciuffetti_2008, title={Pathway, inhibition and regulation of methyl tertiary butyl ether oxidation in a filamentous fungus, Graphium sp}, volume={77}, DOI={10.1007/s00253-007-1268-2}, number={6}, journal={Applied Microbiology and Biotechnology (Internet)}, author={Skinner, K. M. and Martinez-Prado, A. and Hyman, Michael and Williamson, K. J. and Ciuffetti, L. M.}, year={2008}, pages={1359–1365} }
 @article{lee_hyman_luginbuhl_2007, title={The Concept of Readiness in the Academic Department: A Case Study of Undergraduate Education Reform}, volume={32}, ISSN={1573-1758}, url={https://doi.org/10.1007/s10755-006-9032-6}, DOI={10.1007/s10755-006-9032-6}, abstractNote={While there has been emphasis on the institution and individual classroom as loci of learning and reform, less attention has been paid to the academic department. However, precisely because its structure is so endemic to institutions of higher education, the academic department may be the most logical and potent site for change. Using a case study approach, this paper examines the conditions under which change in undergraduate education takes hold and flourishes in the academic department, advances the concept of readiness, and explores its implications for those who wish to promote change in the department.}, number={1}, journal={Innovative Higher Education}, author={Lee, Virginia S. and Hyman, Michael R. and Luginbuhl, Geraldine}, year={2007}, month={Jun}, pages={3–18} }
 @article{johnson_hyman_2006, title={Propane and n-butane oxidation by Pseudomonas putida GPo1}, volume={72}, DOI={10.1128/aem.72.1.950-952.2006}, number={1}, journal={Applied and Environmental Microbiology}, author={Johnson, E. L. and Hyman, Michael}, year={2006}, pages={950–952} }
 @article{johnson_smith_o'reilly_hyman_2004, title={Induction of methyl tertiary butyl ether (MTBE)-oxidizing activity in Mycobacterium vaccae JOB5 by MTBE}, volume={70}, ISSN={0099-2240}, DOI={10.1128/AEM.70.2.1023-1030.2004}, abstractNote={Alkane-grown cells of Mycobacterium vaccae JOB5 cometabolically degrade the gasoline oxygenate methyl tertiary butyl ether (MTBE) through the activities of an alkane-inducible monooxygenase and other enzymes in the alkane oxidation pathway. In this study we examined the effects of MTBE on the MTBE-oxidizing activity of M. vaccae JOB5 grown on diverse nonalkane substrates. Carbon-limited cultures were grown on glycerol, lactate, several sugars, and tricarboxylic acid cycle intermediates, both in the presence and absence of MTBE. In all MTBE-containing cultures, MTBE consumption occurred and tertiary butyl alcohol (TBA) and tertiary butyl formate accumulated in the culture medium. Acetylene, a specific inactivator of alkane- and MTBE-oxidizing activities, fully inhibited MTBE consumption and product accumulation but had no other apparent effects on culture growth. The MTBE-dependent stimulation of MTBE-oxidizing activity in fructose- and glycerol-grown cells was saturable with respect to MTBE concentration (50% saturation level = 2.4 to 2.75 mM), and the onset of MTBE oxidation in glycerol-grown cells was inhibited by both rifampin and chloramphenicol. Other oxygenates (TBA and tertiary amyl methyl ether) also induced the enzyme activity required for their own degradation in glycerol-grown cells. Presence of MTBE also promoted MTBE oxidation in cells grown on organic acids, compounds that are often found in anaerobic, gasoline-contaminated environments. Experiments with acid-grown cells suggested induction of MTBE-oxidizing activity by MTBE is subject to catabolite repression. The results of this study are discussed in terms of their potential implications towards our understanding of the role of cometabolism in MTBE and TBA biodegradation in gasoline-contaminated environments.}, number={2}, journal={Applied and Environmental Microbiology}, author={Johnson, Erika L. and Smith, Christy A. and O'Reilly, Kirk T. and Hyman, Michael R.}, year={2004}, month={Feb}, pages={1023–1030} }
 @article{smith_hyman_2004, title={Oxidation of methyl tert-butyl ether by alkane hydroxylase in dicyclopropylketone-induced and n-octane-grown Pseudomonas putida GPo1}, volume={70}, ISSN={0099-2240}, DOI={10.1128/AEM.70.8.4544-4550.2004}, abstractNote={The alkane hydroxylase enzyme system in Pseudomonas putida GPo1 has previously been reported to be unreactive toward the gasoline oxygenate methyl tert-butyl ether (MTBE). We have reexamined this finding by using cells of strain GPo1 grown in rich medium containing dicyclopropylketone (DCPK), a potent gratuitous inducer of alkane hydroxylase activity. Cells grown with DCPK oxidized MTBE and generated stoichiometric quantities of tert-butyl alcohol (TBA). Cells grown in the presence of DCPK also oxidized tert-amyl methyl ether but did not appear to oxidize either TBA, ethyl tert-butyl ether, or tert-amyl alcohol. Evidence linking MTBE oxidation to alkane hydroxylase activity was obtained through several approaches. First, no TBA production from MTBE was observed with cells of strain GPo1 grown on rich medium without DCPK. Second, no TBA production from MTBE was observed in DCPK-treated cells of P. putida GPo12, a strain that lacks the alkane-hydroxylase-encoding OCT plasmid. Third, all n-alkanes that support the growth of strain GPo1 inhibited MTBE oxidation by DCPK-treated cells. Fourth, two non-growth-supporting n-alkanes (propane and n-butane) inhibited MTBE oxidation in a saturable, concentration-dependent process. Fifth, 1,7-octadiyne, a putative mechanism-based inactivator of alkane hydroxylase, fully inhibited TBA production from MTBE. Sixth, MTBE-oxidizing activity was also observed in n-octane-grown cells. Kinetic studies with strain GPo1 grown on n-octane or rich medium with DCPK suggest that MTBE-oxidizing activity may have previously gone undetected in n-octane-grown cells because of the unusually high K(s) value (20 to 40 mM) for MTBE.}, number={8}, journal={Applied and Environmental Microbiology}, author={Smith, Christy A. and Hyman, Michael R.}, year={2004}, month={Aug}, pages={4544–4550} }
 @book{lee_greene_wellman_al._2004, title={Teaching and learning through inquiry: A guidebook for institutions and instructors}, publisher={Sterling, Va.: Stylus Pub.}, author={Lee, V. S. and Greene, D. B. and Wellman, D. J. and al.}, year={2004} }
 @article{pon_hyman_semprini_2003, title={Acetylene inhibition of trichloroethene and vinyl chloride reductive dechlorination}, volume={37}, DOI={10.1021/es026352i}, number={14}, journal={Environmental Science & Technology}, author={Pon, G. and Hyman, Michael and Semprini, L.}, year={2003}, pages={3181–3188} }
 @article{smith_o'reilly_hyman_2003, title={Characterization of the initial reactions during the cometabolic oxidation of methyl tert-butyl ether by propane-grown Mycobacterium vaccae JOB5}, volume={69}, ISSN={0099-2240}, DOI={10.1128/AEM.69.2.796-804.2003}, abstractNote={The initial reactions in the cometabolic oxidation of the gasoline oxygenate, methyl tert-butyl ether (MTBE), by Mycobacterium vaccae JOB5 have been characterized. Two products, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), rapidly accumulated extracellularly when propane-grown cells were incubated with MTBE. Lower rates of TBF and TBA production from MTBE were also observed with cells grown on 1- or 2-propanol, while neither product was generated from MTBE by cells grown on casein-yeast extract-dextrose broth. Kinetic studies with propane-grown cells demonstrated that TBF is the dominant (> or = 80%) initial product of MTBE oxidation and that TBA accumulates from further biotic and abiotic hydrolysis of TBF. Our results suggest that the biotic hydrolysis of TBF is catalyzed by a heat-stable esterase with activity toward several other tert-butyl esters. Propane-grown cells also oxidized TBA, but no further oxidation products were detected. Like the oxidation of MTBE, TBA oxidation was fully inhibited by acetylene, an inactivator of short-chain alkane monooxygenase in M. vaccae JOB5. Oxidation of both MTBE and TBA was also inhibited by propane (K(i) = 3.3 to 4.4 microM). Values for K(s) of 1.36 and 1.18 mM and for V(max) of 24.4 and 10.4 nmol min(-1) mg of protein(-1) were derived for MTBE and TBA, respectively. We conclude that the initial steps in the pathway of MTBE oxidation by M. vaccae JOB5 involve two reactions catalyzed by the same monooxygenase (MTBE and TBA oxidation) that are temporally separated by an esterase-catalyzed hydrolysis of TBF to TBA. These results that suggest the initial reactions in MTBE oxidation by M. vaccae JOB5 are the same as those that we have previously characterized in gaseous alkane-utilizing fungi.}, number={2}, journal={Applied and Environmental Microbiology}, author={Smith, Christy A. and O'Reilly, Kirk T. and Hyman, Michael R.}, year={2003}, month={Feb}, pages={796–804} }
 @article{smith_o'reilly_hyman_2003, title={Cometabolism of methyl tertiary butyl ether and gaseous n-alkanes by Pseudomonas mendocina KR-1 grown on C5 to C8 n-alkanes}, volume={69}, ISSN={0099-2240}, DOI={10.1128/AEM.69.12.7385-7394.2003}, abstractNote={Pseudomonas mendocina KR-1 grew well on toluene, n-alkanes (C5 to C8), and 1 degrees alcohols (C2 to C8) but not on other aromatics, gaseous n-alkanes (C1 to C4), isoalkanes (C4 to C6), 2 degrees alcohols (C3 to C8), methyl tertiary butyl ether (MTBE), or tertiary butyl alcohol (TBA). Cells grown under carbon-limited conditions on n-alkanes in the presence of MTBE (42 micromoles) oxidized up to 94% of the added MTBE to TBA. Less than 3% of the added MTBE was oxidized to TBA when cells were grown on either 1 degrees alcohols, toluene, or dextrose in the presence of MTBE. Concentrated n-pentane-grown cells oxidized MTBE to TBA without a lag phase and without generating tertiary butyl formate (TBF) as an intermediate. Neither TBF nor TBA was consumed by n-pentane-grown cells, while formaldehyde, the expected C1 product of MTBE dealkylation, was rapidly consumed. Similar Ks values for MTBE were observed for cells grown on C5 to C8 n-alkanes (12.95 +/- 2.04 mM), suggesting that the same enzyme oxidizes MTBE in cells grown on each n-alkane. All growth-supporting n-alkanes (C5 to C8) inhibited MTBE oxidation by resting n-pentane-grown cells. Propane (Ki = 53 micromoles) and n-butane (Ki = 16 micromoles) also inhibited MTBE oxidation, and both gases were also consumed by cells during growth on n-pentane. Cultures grown on C5 to C8 n-alkanes also exhibited up to twofold-higher levels of growth in the presence of propane or n-butane, whereas no growth stimulation was observed with methane, ethane, MTBE, TBA, or formaldehyde. The results are discussed in terms of their impacts on our understanding of MTBE biodegradation and cometabolism.}, number={12}, journal={Applied and Environmental Microbiology}, author={Smith, Christy A. and O'Reilly, Kirk T. and Hyman, Michael R.}, year={2003}, month={Dec}, pages={7385–7394} }
 @article{chang_hyman_williamson_2002, title={Cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, Nitrosomonas europaea}, volume={13}, number={6}, journal={Biodegradation (Dordrecht)}, author={Chang, S. W. and Hyman, M. R. and Williamson, K. J.}, year={2002}, pages={373–381} }
 @article{cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, nitrosomonas europaea._2002, DOI={10.1023/a:1022811430030}, journal={Biodegradation}, year={2002}, month={Jan} }
 @article{o'reilly_moir_taylor_smith_hyman_2001, title={Hydrolysis of tert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid}, volume={35}, ISSN={0013-936X}, url={https://doi.org/10.1021/es001431k}, DOI={10.1021/es001431k}, abstractNote={tert-Butyl methyl ether (MTBE) is generally considered to be resistant to chemical transformation in aqueous solution. This lack of reactivity has led to concerns of the long-term impacts of MTBE in groundwater. Although hydrolysis in the presence of strong acids has been recognized as a mechanism for MTBE transformation, it has been discounted as a significant reaction under environmental conditions. In this study, we have examined the fate of MTBE and other ether oxygenates under moderately acidic conditions (≥ pH 1). The results demonstrate that MTBE is sensitive to acid-catalyzed hydrolysis reaction that generates tert-butyl alcohol (TBA) and methanol as products. The reaction is first-order with respect to the concentration of MTBE and hydronium ion with a second-order rate constant of about 0.9 × 10-2 M-1 h-1 at 26 °C. Commercially available acidic ion-exchange resins were also shown to catalyze the hydrolysis of MTBE at near neutral pH. Pseudo-first-order rate constants were observed to be as high as 0.03 h-1 at 25 °C and 0.12 h-1 at 35 °C. These findings are discussed in terms of their possible implications for the treatment and environmental fate of MTBE and other gasoline oxygenates.}, number={19}, journal={Environmental Science & Technology}, author={O'Reilly, Kirk T. and Moir, Michael E. and Taylor, Christine D. and Smith, Christy A. and Hyman, Michael R.}, year={2001}, month={Oct}, pages={3954–3961} }
 @article{arp_yeager_hyman_2001, title={Molecular and cellular fundamentals of aerobic cometabolism of trichloroethylene}, volume={12}, number={2}, journal={Biodegradation (Dordrecht)}, author={Arp, D. J. and Yeager, C. M. and Hyman, M. R.}, year={2001}, pages={81–103} }
 @article{molecular and cellular fundamentals of aerobic cometabolism of trichloroethylene._2001, DOI={10.1023/a:1012089908518}, journal={Biodegradation}, year={2001}, month={Jan} }
 @article{vancheeswaran_hyman_semprini_1999, title={Anaerobic Biotransformation of Trichlorofluoroethene in Groundwater Microcosms}, volume={33}, ISSN={0013-936X}, url={https://doi.org/10.1021/es9811952}, DOI={10.1021/es9811952}, abstractNote={The biological reduction of trichlorofluoroethene (TCFE) was investigated in anaerobic groundwater microcosms. TCFE was reductively dehalogenated by microorganisms to produce three dichlorofluoroethene isomers, with cis-1,2-dichlorofluoroethene (c-DCFE) being the main isomer formed. Further sequential biological transformation of these compounds to mono-chlorofluoroethene isomers was incomplete and occurred at much slower rates. The rates of TCFE reduction were compared to the rates of reduction of two common chlorinated solvents, perchloroethene (PCE) and trichloroethene (TCE), when present at similar concentrations. Aqueous concentrations ranged from 7.0 to 14.0 mg/L for TCFE and from 7.5 to 15.0 mg/L for PCE and TCE. Similar rates of PCE and TCE transformation relative to TCFE were observed in single-compound tests (PCE, TCE, and TCFE in separate microcosms) and when the contaminants were present together as mixtures in the microcosms. The close similarities between the time course and kinetics of TCFE degradation and the degradation of both PCE and TCE, when present at comparable initial concentrations, suggest that TCFE could potentially be used as a benign reactive tracer to measure in-situ rates of PCE and TCE transformation in contaminated environments.}, number={12}, journal={Environmental Science & Technology}, author={Vancheeswaran, Sanjay and Hyman, Michael R. and Semprini, Lewis}, year={1999}, month={Jun}, pages={2040–2045} }
 @article{cometabolism of chlorinated solvents by nitrifying bacteria: kinetics, substrate interactions, toxicity effects, and bacterial response _1999, DOI={10.1002/(sici)1097-0290(19990620)63:6<756::aid-bit14>3.0.co;2-z}, journal={Biotechnology and bioengineering}, year={1999}, month={Jun} }
 @article{yeager_bottomley_arp_hyman_1999, title={Inactivation of toluene 2-monooxygenase in Burkholderia cepacia G4 by alkynes}, volume={65}, ISSN={0099-2240}, abstractNote={High concentrations of acetylene (10 to 50% [vol/vol] gas phase) were required to inhibit the growth of Burkholderia cepacia G4 on toluene, while 1% (vol/vol) (gas phase) propyne or 1-butyne completely inhibited growth. Low concentrations of longer-chain alkynes (C5 to C10) were also effective inhibitors of toluene-dependent growth, and 2- and 3-alkynes were more potent inhibitors than their 1-alkyne counterparts. Exposure of toluene-grown B. cepacia G4 to alkynes resulted in the irreversible loss of toluene- and o-cresol-dependent O2 uptake activities, while acetate- and 3-methylcatechol-dependent O2 uptake activities were unaffected. Toluene-dependent O2 uptake decreased upon the addition of 1-butyne in a concentration- and time-dependent manner. The loss of activity followed first-order kinetics, with apparent rate constants ranging from 0.25 min-1 to 2.45 min-1. Increasing concentrations of toluene afforded protection from the inhibitory effects of 1-butyne. Furthermore, oxygen, supplied as H2O2, was required for inhibition by 1-butyne. These results suggest that alkynes are specific, mechanism-based inactivators of toluene 2-monooxygenase in B. cepacia G4, although the simplest alkyne, acetylene, was relatively ineffective compared to longer alkynes. Alkene analogs of acetylene and propyne-ethylene and propylene-were not inactivators of toluene 2-monooxygenase activity in B. cepacia G4 but were oxidized to their respective epoxides, with apparent Ks and Vmax values of 39.7 microM and 112.3 nmol min-1 mg of protein-1 for ethylene and 32.3 microM and 89.2 nmol min-1 mg of protein-1 for propylene.}, number={2}, journal={Applied and Environmental Microbiology}, author={Yeager, C. M. and Bottomley, P. J. and Arp, D. J. and Hyman, M. R.}, year={1999}, month={Feb}, pages={632–639} }
 @article{inactivation of toluene 2-monooxygenase in burkholderia cepacia g4 by alkynes._1999, journal={Applied and environmental microbiology}, year={1999}, month={Feb} }
 @article{schroth_istok_conner_hyman_haggerty_o'reilly_1998, title={Spatial Variability in In Situ Aerobic Respiration and Denitrification Rates in a Petroleum-Contaminated Aquifer}, volume={36}, ISSN={1745-6584}, url={https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1745-6584.1998.tb02099.x}, DOI={10.1111/j.1745-6584.1998.tb02099.x}, abstractNote={An extensive series of single-well, push-pull tests was performed to quantify horizontal and vertical spatial variability in aerobic respiration and denitrification rates in a petroleum-contaminated aquifer. The results indicated rapid consumption of injected O2 or NO3− in shallow and deep test intervals across a large portion of the site. Computed first-order rate coefficients for aerobic respiration ranged from 0.15 to 1.69 h−1 in the shallow test interval, and from 0.08 to 0.83 h−1 in the deep test interval. The largest aerobic respiration rates occurred on the upgradient edge of the contaminant plume where concentrations of petroleum hydrocarbons and dissolved O2 were relatively high. Computed first-order rate coefficients for denitrification ranged from 0.09 to 0.42 h−1 in the shallow test interval, and from 0.11 to 0.28 h−1 in the deep test interval. The largest denitrification rates occurred on the downgradient edge of the plume where hydrocarbon concentrations were relatively high but dissolved oxygen concentrations were small. The rates reported here represent maximal rates of aerobic respiration and denitrification, as supported by high concentrations of electron acceptors in the injected test solutions. Production of dissolved CO2 during aerobic respiration and denitrification tests provided evidence that O2 and NO3− consumption was largely due to microbial activity. Additional evidence for microbial NO3− consumption was provided by reduced rates of NO3−consumption when dissolved O2 was injected with NO3−, and by increased N2O production when C2H2 was injected with NO3−.}, number={6}, journal={Groundwater}, author={Schroth, M. H. and Istok, J. D. and Conner, G. T. and Hyman, M. R. and Haggerty, R. and O'Reilly, K. T.}, year={1998}, pages={924–937} }
 @article{ely_williamson_hyman_arp_1997, title={Cometabolism of chlorinated solvents by nitrifying bacteria: kinetics, substrate interactions, toxicity effects, and bacterial response}, volume={54}, ISSN={0006-3592}, DOI={10.1002/(SICI)1097-0290(19970620)54:6<520::AID-BIT3>3.0.CO;2-L}, abstractNote={Pure cultures of ammonia-oxidizing bacteria, Nitrosomonas europaea, were exposed to trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), chloroform (CF), 1,2-dichloroethane (1,2-DCA), or carbon tetrachloride (CT), in the presence of ammonia, in a quasi-steady-state bioreactor. Estimates of enzyme kinetics constants, solvent inactivation constants, and culture recovery constants were obtained by simultaneously fitting three model curves to experimental data using nonlinear optimization techniques and an enzyme kinetics model, referred to as the inhibition, inactivation, and recovery (IIR) model, that accounts for inhibition of ammonia oxidation by the solvent, enzyme inactivation by solvent product toxicity, and respondent synthesis of new enzyme (recovery). Results showed relative enzyme affinities for ammonia monooxygenase (AMO) of 1,1-DCE approximately TCE > CT > NH(3) > CF > 1,2-DCA. Relative maximum specific substrate transformation rates were NH(3) > 1,2-DCA > CF > TCE approximately 1,1-DCE > CT (=0). The TCE, CF, and 1,1-DCE inactivated the cells, with 1,1-DCE being about three times more potent than TCE or CF. Under the conditions of these experiments, inactivating injuries caused by TCE and 1,1-DCE appeared limited primarily to the AMO enzyme, but injuries caused by CF appeared to be more generalized. The CT was not oxidized by N. europaea while 1,2-DCA was oxidized quite readily and showed no inactivation effects. Recovery capabilities were demonstrated with all solvents except CF. A method for estimating protein yield, the relationship between the transformation capacity model and the IIR model, and a condition necessary for sustainable cometabolic treatment of inactivating substrates are presented. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 520-534, 1997.}, number={6}, journal={Biotechnology and Bioengineering}, author={Ely, R. L. and Williamson, K. J. and Hyman, M. R. and Arp, D. J.}, year={1997}, month={Jun}, pages={520–534} }
 @article{hardison_curry_ciuffetti_hyman_1997, title={Metabolism of Diethyl Ether and Cometabolism of Methyl tert-Butyl Ether by a Filamentous Fungus, a Graphium sp}, volume={63}, ISSN={0099-2240}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1389222/}, abstractNote={In this study, evidence for two novel metabolic processes catalyzed by a filamentous fungus, Graphium sp. strain ATCC 58400, is presented. First, our results indicate that this Graphium sp. can utilize the widely used solvent diethyl ether (DEE) as the sole source of carbon and energy for growth. The kinetics of biomass accumulation and DEE consumption closely followed each other, and the molar growth yield on DEE was indistinguishable from that with n-butane. n-Butane-grown mycelia also immediately oxidized DEE without the extracellular accumulation of organic oxidation products. This suggests a common pathway for the oxidation of both compounds. Acetylene, ethylene, and other unsaturated gaseous hydrocarbons completely inhibited the growth of this Graphium sp. on DEE and DEE oxidation by n-butane-grown mycelia. Second, our results indicate that gaseous n-alkane-grown Graphium mycelia can cometabolically degrade the gasoline oxygenate methyl tert-butyl ether (MTBE). The degradation of MTBE was also completely inhibited by acetylene, ethylene, and other unsaturated hydrocarbons and was strongly influenced by n-butane. Two products of MTBE degradation, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), were detected. The kinetics of product formation suggest that TBF production temporally precedes TBA accumulation and that TBF is hydrolyzed both biotically and abiotically to yield TBA. Extracellular accumulation of TBA accounted for only a maximum of 25% of the total MTBE consumed. Our results suggest that both DEE oxidation and MTBE oxidation are initiated by cytochrome P-450-catalyzed reactions which lead to scission of the ether bonds in these compounds. Our findings also suggest a potential role for gaseous n-alkane-oxidizing fungi in the remediation of MTBE contamination.}, number={8}, journal={Applied and Environmental Microbiology}, author={Hardison, L. K. and Curry, S. S. and Ciuffetti, L. M. and Hyman, M. R.}, year={1997}, month={Aug}, pages={3059–3067} }
 @article{metabolism of diethyl ether and cometabolism of methyl tert-butyl ether by a filamentous fungus, a graphium sp._1997, journal={Applied and environmental microbiology}, year={1997}, month={Aug} }
 @article{regulation of the synthesis and activity of ammonia monooxygenase in nitrosomonas europaea by altering ph to affect nh(inf3) availability._1997, journal={Applied and environmental microbiology}, year={1997}, month={Nov} }
 @article{stein_arp_hyman_1997, title={Regulation of the synthesis and activity of ammonia monooxygenase in Nitrosomonas europaea by altering pH to affect NH3 availability}, volume={63}, journal={Applied and Environmental Microbiology}, author={Stein, L.Y. and Arp, D.J. and Hyman, M.R.}, year={1997}, pages={4588–4592} }
 @article{istok_humphrey_schroth_hyman_o'reilly_1997, title={Single-Well, “Push-Pull” Test for In Situ Determination of Microbial Activities}, volume={35}, ISSN={1745-6584}, url={https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1745-6584.1997.tb00127.x}, DOI={10.1111/j.1745-6584.1997.tb00127.x}, abstractNote={A single-well, “push-pull” test method is proposed for the in situ determination of microbial metabolic activities in ground-water aquifers. The method consists of the pulse-type injection (“push”) of a test solution into the saturated zone of an aquifer through the screen of an existing monitoring well followed by the extraction (“pull”) of the test solution/ground-water mixture from the same well. The test solution contains a tracer and one or more reactive solutes selected to investigate specific microbial activities. During the injection phase, the test solution flows radially away from the monitoring well into the aquifer. Within the aquifer, biologically reactive components of the test solution are converted to various products by the indigenous microbial community. During the extraction phase, flow is reversed and solute concentrations are measured to obtain breakthrough curves, which are used to compute the quantities of reactant(s) consumed and/or product(s) formed during the test and reaction rates. Tests were performed to determine rates of aerobic respiration, denitrification, sulfate reduction, and methanogenesis in a petroleum contaminated aquifer in western Oregon. High rates of oxygen, nitrate, nitrite, and hydrogen utilization and nitrite, and carbon dioxide production support the hypothesis that petroleum contamination has resulted in an increase in microbial activity in the anaerobic portion of the site. The results suggest that the push-pull test method should be useful for obtaining quantitative information on a wide range of in situ microbial processes.}, number={4}, journal={Groundwater}, author={Istok, J. D. and Humphrey, M. D. and Schroth, M. H. and Hyman, M. R. and O'Reilly, K. T.}, year={1997}, pages={619–631} }
 @article{curry_ciuffetti_hyman_1996, title={Inhibition of Growth of a Graphium sp. on Gaseous n-Alkanes by Gaseous n-Alkynes and n-Alkenes}, volume={62}, ISSN={0099-2240}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1388884/}, abstractNote={The growth of a filamentous fungus, a Graphium sp., on n-alkanes (C(inf2) to C(inf4)) was inhibited by low concentrations of acetylene, propyne, 1-butyne, ethylene, and propylene. Acetylene and other unsaturated hydrocarbons had no effect on the growth of the Graphium sp. on potato dextrose broth, ethanol, or acetate. Our results suggest that n-alkynes and n-alkenes are selective inhibitors of a nonspecific monooxygenase enzyme responsible for the initial oxidation of n-alkanes.}, number={6}, journal={Applied and Environmental Microbiology}, author={Curry, S. and Ciuffetti, L. and Hyman, M.}, year={1996}, month={Jun}, pages={2198–2200} }
 @article{ely_williamson_guenther_hyman_arp_1995, title={A cometabilic kinetics model incorporating enzyme inhbition, inactivation, and recovery: I. Model development, analysis, and testing}, volume={46}, ISSN={0006-3592}, DOI={10.1002/bit.260460305}, abstractNote={Cometabolic biodegradation prcesses are important for bioremediation of hazardous waste sites. However, these proceeses are not well understood and have not been modeled thoroughly. Traditional Michaelis-Menten kinetics models often are used, but toxic effects and bacterial responses to toxicity may cause changes in enzyme levels, rendering such models inappropriate. In this article, a conceptual and mathematical model of cometabolic enzyme kinetics i described. Model derivation is based on enzyme/growth-substrate/nongrowth-substrate interaction and incorporates enzyme inhibition (caused by the presence of a cometabolic compound), inactivation (resulting from toxicity of a cometabolic product), and recovery (associated with bacterial synthesis of new enbzyme in response to inactivation). The mathematical model consists of a system of two, nonlinear ordinary differential equations that can be solved implicitly using numerical methods, providing estimates of model parameters. Model analysis shows that growth substraate adn nongrowth substrate oxidation rates are related by a dimensionless constant. Reliability of tehy model solution prcedure is verifiedl by abnalyzing data ses, containing random error, from simulated experimentss with trichhloroethyylene (TCE) degradation by ammonia-oxidizing bacterialunder various conditions. Estimation of the recovery rate contant is deterimined to be sensitive to intial TCE concentration. Model assumptions are evaluated in a companion article using data from TCE degradation experiments with amoniaoxidizing bacteria. (c) 1995 John Wiley & Sons, Inc.}, number={3}, journal={Biotechnology and Bioengineering}, author={Ely, R. L. and Williamson, K. J. and Guenther, R. B. and Hyman, M. R. and Arp, D. J.}, year={1995}, month={May}, pages={218–231} }
 @article{ely_hyman_arp_guenther_williamson_1995, title={A cometabolic kinetics model incoroporating enzyme inhibition, inactivation, and recovery: II. Trichloroethylene degradaation experiments}, volume={46}, ISSN={0006-3592}, DOI={10.1002/bit.260460306}, abstractNote={A Cometabolism enzyme kinetics model has been presented which takes into account changes in bacterial activity associated with enzyme inhibitiion, inactivation, inactivation of enzyme resulting from product toxicty, and respondent synthesis of new enzyme. Although this process is inherently unsteady-state, the model assumes that cometabolic degradation of a compound exhibiting product toxicity can be modeled as pseudo-steady-staate under certain conditions. In its simplified from, the model also assumes that enzyme inactivation is directly propoertional to nongrawth substrate oxidation, and that recovery is directly proportionla to growth substrate oxidation. In part 1, model drivation, simplification, and analyses were described. In this articles, model assuptiions are tested by analyzing data from experiments exmining trichloroethylene (TCE) degradation by the ammoniaoxidizing baceterium Nitrosomonas europaea in a quasisteady-state bioreactor. Model solution results showed steady-state bioreactor. Model solution results showed TCE to be a competitive inhibitoer of ammonia oxidation, with TCE affinity for ammonia monooxygenase (AMO) being about four times greater than that of ammonia for the enzyme. Inhibition was independent fo TCE oxidation and occurred essentially instantly upon exposure to TCE. In contrast, inactivation of AMO occurred more gradually and was proportional to the rate and amount of TCE oxidized. Evaluation of other O(2)-dependent enzymes and electron transport proteins suggested that TCE-related damage was predominantly confined to AMO. In response to inhibition and/or inactivation, bacterial recovery was initiated, even in the presence of TCE, implying that membranes adn protein synthesis systems were functioning. Analysis of data and comparison of model results showed the inhibition/inactivation/recovery concept to provide a reasonable basis for understandign the effects fo TCE on AMO function and bacterial response. The model assumptions were verified except tht questions remain regarding the factores controlling recovery and its role in the long term. (c) 1995 John Wiley & Sons, Inc.}, number={3}, journal={Biotechnology and Bioengineering}, author={Ely, R. L. and Hyman, M. R. and Arp, D. J. and Guenther, R. B. and Williamson, K. J.}, year={1995}, month={May}, pages={232–245} }
 @article{hyman_arp_1995, title={Effects of ammonia on the de novo synthesis of polypeptides in cells of Nitrosomonas europaea denied ammonia as an energy source}, volume={177}, ISSN={0021-9193}, abstractNote={The effects of ammonium on the de novo synthesis of polypeptides in the soil-nitrifying bacterium Nitrosomonas europaea have been investigated. Cells were incubated in the presence of both acetylene and NH4+. Under these conditions, the cells were unable to utilize NH4+ as an energy source. Energy to support protein synthesis was supplied by the oxidation of hydroxylamine or other alternative substrates for hydroxylamine oxidoreductase. De novo protein synthesis was detected by 14C incorporation from 14CO2 into polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. In the presence of NH4+, acetylene-treated cells synthesized the 27-kDa polypeptide of ammonia monoxygenase (AMO) and two other major polypeptides (with sizes of 55 and 65 kDa). The synthesis of these polypeptides was completely inhibited by chloramphenicol and attenuated by rifampin. The optimal concentration of hydroxylamine for the in vivo 14C-labeling reaction was found to be 2 mM. The effect of NH4+ concentration was also examined. It was shown to cause a saturable response with a Ks of approximately 2.0 mM NH4+. Labeling studies conducted at different pH values suggest cells respond to NH3 rather than NH4+. No other compounds tested were able to influence the synthesis of the 27-kDa component of AMO, although we have also demonstrated that this polypeptide can be synthesized under anaerobic conditions in cells utilizing pyruvate- or hydrazine-dependent nitrite reduction as an energy source. We conclude that ammonia has a regulatory effect on the synthesis of a subunit of AMO in addition to providing nitrogen for protein synthesis.}, number={17}, journal={Journal of Bacteriology}, author={Hyman, M. R. and Arp, D. J.}, year={1995}, month={Sep}, pages={4974–4979} }
 @article{effects of ammonia on the de novo synthesis of polypeptides in cells of nitrosomonas europaea denied ammonia as an energy source._1995, DOI={10.1128/jb.177.17.4974-4979.1995}, journal={Journal of bacteriology}, year={1995}, month={Sep} }
 @article{hyman_russell_ely_williamson_arp_1995, title={Inhibition, Inactivation, and Recovery of Ammonia-Oxidizing Activity in Cometabolism of Trichloroethylene by Nitrosomonas europaea}, volume={61}, ISSN={0099-2240}, abstractNote={The kinetics of the cometabolism of trichloroethylene (TCE) by the ammonia-oxidizing soil bacterium Nitrosomonas europaea in short-term (<10-min) incubations were investigated. Three individual effects of TCE cometabolism on this bacterium were characterized. First, we observed that TCE is a potent competitive inhibitor of ammonia oxidation by N. europaea. The K(infi) value for TCE (30 (mu)M) is similar to the K(infm) for ammonia (40 (mu)M). Second, we examined the toxicity associated with TCE cometabolism by N. europaea. Stationary-phase cells of N. europaea oxidized approximately 60 nmol of TCE per mg of protein before ammonia-oxidizing activity was completely inactivated by reactive intermediates generated during TCE oxidation. At the TCE concentrations used in these experiments, ammonia did not provide significant protection against inactivation. Third, we have determined the ability of cells to recover ammonia-oxidizing activity after exposure to TCE. Cells recovering from TCE inactivation were compared with cells recovering from the specific inactivation of ammonia-oxidizing activity by light. The recovery kinetics were indistinguishable when 40% or less of the activity was inactivated. However, at increased levels of inactivation, TCE-inactivated cells did not recover as rapidly as light-inactivated cells. The kinetics of recovery appear to be dependent on both the extent of inactivation of ammonia-oxidizing activity and the degree of specificity of the inactivating treatment.}, number={4}, journal={Applied and Environmental Microbiology}, author={Hyman, M. R. and Russell, S. A. and Ely, R. L. and Williamson, K. J. and Arp, D. J.}, year={1995}, month={Apr}, pages={1480–1487} }
 @article{inhibition, inactivation, and recovery of ammonia-oxidizing activity in cometabolism of trichloroethylene by nitrosomonas europaea._1995, journal={Applied and environmental microbiology}, year={1995}, month={Apr} }
 @article{juliette_hyman_arp_1995, title={Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro}, volume={177}, ISSN={0021-9193}, abstractNote={We investigated the effects of bovine serum albumin (BSA) on both the assay and the stability of ammonia-oxidizing activity in cell extracts of Nitrosomonas europaea. Ammonia-dependent O2 uptake activity of freshly prepared extracts did not require BSA. However, a dependence on BSA developed in extracts within a short time. The role of BSA in the assay of ammonia-oxidizing activity apparently is to absorb endogenous free fatty acids which are present in the extracts, because (i) only proteins which bind fatty acids, e.g., BSA or beta-lactoglobulin, supported ammonia-oxidizing activity; (ii) exogenous palmitoleic acid completely inhibited ammonia-dependent O2 uptake activity; (iii) the inhibition caused by palmitoleic acid was reversed only by proteins which bind fatty acids; and (iv) the concentration of endogenous free palmitoleic acid increased during aging of cell extracts. Additionally, the presence of BSA (10 mg/ml) or CuCl2 (500 microM) stabilized ammonia-dependent O2 uptake activity for 2 to 3 days at 4 degrees C. The stabilizing effect of BSA or CuCl2 was apparently due to an inhibition of lipolysis, because both additives inhibited the increase in concentrations of free palmitoleic acid in aging extracts. Other additives which are known to modify lipase activity were also found to stabilize ammonia-oxidizing activity. These additives included HgCl2, lecithin, and phenylmethylsulfonyl fluoride.}, number={17}, journal={Journal of Bacteriology}, author={Juliette, L. Y. and Hyman, M. R. and Arp, D. J.}, year={1995}, month={Sep}, pages={4908–4913} }
 @article{roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro._1995, DOI={10.1128/jb.177.17.4908-4913.1995}, journal={Journal of bacteriology}, year={1995}, month={Sep} }
 @article{hyman_page_arp_1994, title={Oxidation of methyl fluoride and dimethyl ether by ammonia monooxygenase in Nitrosomonas europaea}, volume={60}, ISSN={0099-2240}, abstractNote={Methyl fluoride and dimethyl ether were previously identified as inhibitors of ammonia oxidation and N2O production in autotrophic nitrifying bacteria. We demonstrate that methyl fluoride and dimethyl ether are substrates for ammonia monooxygenase and are converted to formaldehyde and a mixture of methanol and formaldehyde, respectively.}, number={8}, journal={Applied and Environmental Microbiology}, author={Hyman, M. R. and Page, C. L. and Arp, D. J.}, year={1994}, month={Aug}, pages={3033–3035} }
 @article{oxidation of methyl fluoride and dimethyl ether by ammonia monooxygenase in nitrosomonas europaea._1994, journal={Applied and environmental microbiology}, year={1994}, month={Aug} }
 @article{hyman_arp_1993, title={An electrophoretic study of the thermal- and reductant-dependent aggregation of the 27 kDa component of ammonia monooxygenase from Nitrosomonas europaea}, volume={14}, ISSN={0173-0835}, abstractNote={Standard protocols for sample preparation for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) typically involve the combined use of heat and a reductant to fully disrupt protein-protein interactions and allow for constant ratios of SDS-binding to individual polypeptides. However, 14C-labeled forms of the membrane-bound, active-site-containing 27 kDa polypeptide of ammonia monooxygenase from Nitrosomonas europaea undergo an aggregation reaction when cells or membranes are heated in the presence of SDS-PAGE sample buffer. The aggregate produced after heating at 100 degrees C is a soluble complex which fails to enter the stacking gel in discontinuous SDS-PAGE gels. The extent of the aggregation reaction is dependent on the temperature of sample preparation, and the reaction exhibits first-order kinetics at 65 degrees C and 100 degrees C (rates constants = 0.07 and 0.35 min-1, respectively). The rate of the aggregation reaction is further dependent on the concentration of reductant used in the sample buffer. However, the concentration of SDS does not significantly affect the rate of aggregation. The aggregated form of the 27 kDA polypeptide can be isolated by gel-permeation chromatography in the presence of SDS. The aggregated protein can also be returned to the monomeric state by incubation at high pH in the presence of SDS. The aggregation reaction also occurs with 14C2H2-labeled polypeptides in other species of autotrophic nitrifiers and a methanotrophic bacterium which expresses the particulate form of methane monooxygenase. We conclude that strongly hydrophobic amino acid sequences present in ammonia monooxygenase are responsible for the aggregation phenomenon.}, number={7}, journal={Electrophoresis}, author={Hyman, M. R. and Arp, D. J.}, year={1993}, month={Jul}, pages={619–627} }
 @article{an electrophoretic study of the thermal- and reductant-dependent aggregation of the 27 kda component of ammonia monooxygenase from nitrosomonas europaea._1993, DOI={10.1002/elps.1150140197}, journal={Electrophoresis}, year={1993}, month={Jul} }
 @article{ensign_hyman_arp_1993, title={In vitro activation of ammonia monooxygenase from Nitrosomonas europaea by copper.}, volume={175}, ISSN={0021-9193}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC204278/}, abstractNote={The effect of copper on the in vivo and in vitro activity of ammonia monooxygenase (AMO) from the nitrifying bacterium Nitrosomonas europaea was investigated. The addition of CuCl2 to cell extracts resulted in 5- to 15-fold stimulation of ammonia-dependent O2 consumption, ammonia-dependent nitrite production, and hydrazine-dependent ethane oxidation. AMO activity was further stimulated in vitro by the presence of stabilizing agents, including serum albumins, spermine, or MgCl2. In contrast, the addition of CuCl2 and stabilizing agents to whole-cell suspensions did not result in any stimulation of AMO activity. The use of the AMO-specific suicide substrate acetylene revealed two populations of AMO in cell extracts. The low, copper-independent (residual) AMO activity was completely inactivated by acetylene in the absence of exogenously added copper. In contrast, the copper-dependent (activable) AMO activity was protected against acetylene inactivation in the absence of copper. However, in the presence of copper both populations of AMO were inactivated by acetylene. [14C]acetylene labelling of the 27-kDa polypeptide of AMO revealed the same extent of label incorporation in both whole cells and optimally copper-stimulated cell extracts. In the absence of copper, the label incorporation in cell extracts was proportional to the level of residual AMO activity. Other metal ions tested, including Zn2+, Co2+, Ni2+, Fe2+, Fe3+, Ca2+, Mg2+, Mn2+, Cr3+, and Ag+, were ineffective at stimulating AMO activity or facilitating the incorporation of 14C label from [14C]acetylene into the 27-kDa polypeptide. On the basis of these results, we propose that loss of AMO activity upon lysis of N. europaea results from the loss of copper from AMO, generating a catalytically inactive, yet stable and activable, form of the enzyme.}, number={7}, journal={Journal of Bacteriology}, author={Ensign, S A and Hyman, M R and Arp, D J}, year={1993}, month={Apr}, pages={1971–1980} }
 @article{in vitro activation of ammonia monooxygenase from nitrosomonas europaea by copper._1993, DOI={10.1128/jb.175.7.1971-1980.1993}, journal={Journal of bacteriology}, year={1993}, month={Apr} }
 @article{juliette_hyman_arp_1993, title={Inhibition of Ammonia Oxidation in Nitrosomonas europaea by Sulfur Compounds: Thioethers Are Oxidized to Sulfoxides by Ammonia Monooxygenase}, volume={59}, ISSN={0099-2240}, abstractNote={Organic sulfur compounds are well-known nitrification inhibitors. The inhibitory effects of dimethylsulfide, dimethyldisulfide, and ethanethiol on ammonia oxidation by Nitrosomonas europaea were examined. Both dimethylsulfide and dimethyldisulfide were weak inhibitors of ammonia oxidation and exhibited inhibitory characteristics typical of substrates for ammonia monooxygenase (AMO). Depletion of dimethylsulfide required O(2) and was prevented with either acetylene or allylthiourea, two inhibitors of AMO. The inhibition of ammonia oxidation by dimethylsulfide was examined in detail. Cell suspensions incubated in the presence of ammonia oxidized dimethylsulfide to dimethyl sulfoxide. Depletion of six other thioethers was also prevented by treating cell suspensions with either allylthiourea or acetylene. The oxidative products of three thioethers were identified as the corresponding sulfoxides. The amount of sulfoxide formed accounted for a majority of the amount of sulfide depleted. By using gas chromatography coupled with mass spectrometry, allylmethylsulfide was shown to be oxidized to allylmethylsulfoxide by N. europaea with the incorporation of a single atom of O derived from O(2) into the sulfide. This result supported our conclusion that a monooxygenase was involved in the oxidation of allylmethylsulfide. The thioethers are concluded to be a new class of substrates for AMO. This is the first report of the oxidation of the sulfur atom by AMO in whole cells of N. europaea. The ability of N. europaea to oxidize dimethylsulfide is not unique among the ammonia-oxidizing bacteria. Nitrosococcus oceanus, a marine nitrifier, was also demonstrated to oxidize dimethylsulfide to dimethyl sulfoxide.}, number={11}, journal={Applied and Environmental Microbiology}, author={Juliette, L. Y. and Hyman, M. R. and Arp, D. J.}, year={1993}, month={Nov}, pages={3718–3727} }
 @article{inhibition of ammonia oxidation in nitrosomonas europaea by sulfur compounds: thioethers are oxidized to sulfoxides by ammonia monooxygenase._1993, journal={Applied and environmental microbiology}, year={1993}, month={Nov} }
 @article{juliette_hyman_arp_1993, title={Mechanism-Based Inactivation of Ammonia Monooxygenase in Nitrosomonas europaea by Allylsulfide}, volume={59}, ISSN={0099-2240}, abstractNote={Allylsulfide caused an irreversible inactivation of ammonia monooxygenase (AMO) activity (ammonia-dependent O(2) uptake) in Nitrosomonas europaea. The hydroxylamine oxidoreductase activity (hydrazine-dependent O(2) uptake) of cells was unaffected by allylsulfide. Anaerobic conditions or the presence of allylthiourea, a reversible noncompetitive AMO inhibitor, protected AMO from inactivation by allylsulfide. Ammonia did not protect AMO from inactivation by allylsulfide but instead increased the rate of inactivation. The inactivation of AMO followed pseudo-first-order kinetics, but the observed rates did not saturate with increasing allylsulfide concentrations. The time course of recovery of AMO-dependent nitrite production after complete inactivation by allylsulfide required de novo protein synthesis. Incubation of cells with allylsulfide prevented the C label from C(2)H(2) (a suicide mechanism-based inactivator of AMO) from being incorporated into the 27-kDa polypeptide of AMO. Some compounds structurally related to allylsulfide were unable to inactivate AMO. We conclude that allylsulfide is a specific, mechanism-based inactivator of AMO in N. europaea.}, number={11}, journal={Applied and Environmental Microbiology}, author={Juliette, L. Y. and Hyman, M. R. and Arp, D. J.}, year={1993}, month={Nov}, pages={3728–3735} }
 @article{mechanism-based inactivation of ammonia monooxygenase in nitrosomonas europaea by allylsulfide._1993, journal={Applied and environmental microbiology}, year={1993}, month={Nov} }
 @article{hyman_arp_1992, title={14C2H2- and 14CO2-labeling studies of the de novo synthesis of polypeptides by Nitrosomonas europaea during recovery from acetylene and light inactivation of ammonia monooxygenase}, volume={267}, ISSN={0021-9258}, abstractNote={Incubation of cells of the nitrifying bacterium Nitrosomonas europaea with 14C2H2 results in the covalent attachment of 14C label to a membrane-bound polypeptide of an approximate Mr of 28,000 (Hyman, M.R., and Wood, P.M. (1985) Biochem. J. 227, 719-725). A labeling procedure using 14C2H2 generated from Ba14CO3 has been used to investigate the correlation between the extent of covalent modification of this polypeptide by 14C from 14C2H2 and the level of ammonia oxidizing activity in whole cells. The time-dependent inactivation of ammonia monooxygenase by 14C2H2 resulted in a progressive and saturable incorporation of 14C into a 27-kDa polypeptide. In contrast, the specific, time-dependent and complete inactivation of ammonia monooxygenase by light resulted in concomitant decrease in the ability of cells to incorporate 14C from 14C2H2 into this polypeptide. The 14C2H2 labeling procedure was also used to investigate the recovery of ammonia monooxygenase activity after complete inactivation of pre-existing ammonia monooxygenase by either C2H2 or light. The recovery of ammonia monooxygenase activity was closely correlated with a recovery of ability of cells to incorporate 14C label from 14C2H2 into the 27-kDa polypeptide. This recovery process was energy (NH4+)-dependent and was inhibited by chloramphenicol and rifampicin, implying that de novo protein synthesis was required. Additional polypeptides labeled with 14C from 14CO2 were also identified during recovery from C2H2 or light inactivation of ammonia monooxygenase.}, number={3}, journal={The Journal of Biological Chemistry}, author={Hyman, M. R. and Arp, D. J.}, year={1992}, month={Jan}, pages={1534–1545} }
 @article{14c2h2- and 14co2-labeling studies of the de novo synthesis of polypeptides by nitrosomonas europaea during recovery from acetylene and light inactivation of ammonia monooxygenase._1992, journal={The Journal of biological chemistry}, year={1992}, month={Jan} }
 @article{acetylene inhibition of azotobacter vinelandii hydrogenase: acetylene binds tightly to the large subunit._1992, DOI={10.1021/bi00127a016}, journal={Biochemistry}, year={1992}, month={Mar} }
 @article{jin-hua_hyman_arp_1992, title={C2H2 Inhibition of Azotobacter vinelandii hydrogenase: C2H2 binds tightly to the large subunit}, volume={31}, journal={Biochemistry}, author={Jin-Hua, S. and Hyman, M.R. and Arp, D.J.}, year={1992}, pages={3158–3165} }
 @article{ensign_hyman_arp_1992, title={Cometabolic degradation of chlorinated alkenes by alkene monooxygenase in a propylene-grown Xanthobacter strain}, volume={58}, ISSN={0099-2240}, abstractNote={Propylene-grown Xanthobacter cells (strain Py2) degraded several chlorinated alkenes of environmental concern, including trichloroethylene, 1-chloroethylene (vinyl chloride), cis- and trans-1,2-dichloroethylene, 1,3-dichloropropylene, and 2,3-dichloropropylene. 1,1-Dichloroethylene was not degraded efficiently, while tetrachloroethylene was not degraded. The role of alkene monooxygenase in catalyzing chlorinated alkene degradations was established by demonstrating that glucose-grown cells which lack alkene monooxygenase and propylene-grown cells in which alkene monooxygenase was selectively inactivated by propyne were unable to degrade the compounds. C2 and C3 chlorinated alkanes were not oxidized by alkene monooxygenase, but a number of these compounds were inhibitors of propylene and ethylene oxidation, suggesting that they compete for binding to the enzyme. A number of metabolites enhanced the rate of degradation of chlorinated alkenes, including propylene oxide, propionaldehyde, and glucose. Propylene stimulated chlorinated alkene oxidation slightly when present at a low concentration but became inhibitory at higher concentrations. Toxic effects associated with chlorinated alkene oxidations were determined by measuring the propylene oxidation and propylene oxide-dependent O2 uptake rates of cells previously incubated with chlorinated alkenes. Compounds which were substrates for alkene monooxygenase exhibited various levels of toxicity, with 1,1-dichloroethylene and trichloroethylene being the most potent inactivators of propylene oxidation and 1,3- and 2,3-dichloropropylene being the most potent inactivators of propylene oxide-dependent O2 uptake. No toxic effects were seen when cells were incubated with chlorinated alkenes anaerobically, indicating that the product(s) of chlorinated alkene oxidation mediates toxicity.}, number={9}, journal={Applied and Environmental Microbiology}, author={Ensign, S. A. and Hyman, M. R. and Arp, D. J.}, year={1992}, month={Sep}, pages={3038–3046} }
 @article{cometabolic degradation of chlorinated alkenes by alkene monooxygenase in a propylene-grown xanthobacter strain._1992, journal={Applied and environmental microbiology}, year={1992}, month={Sep} }
 @article{hyman_seefeldt_morgan_arp_mortenson_1992, title={Kinetic and spectroscopic analysis of the inactivating effects of nitric oxide on the individual components of Azotobacter vinelandii nitrogenase}, volume={31}, ISSN={0006-2960}, abstractNote={The effects of nitric oxide (NO) on the individual components of Azotobacter vinelandii nitrogenase have been examined by kinetic and spectroscopic methods. Incubation of the Fe protein (Av2) for 1 h with stoichiometries of 4- and 8-fold molar excesses of NO to Av2 dimer resulted in a complete loss of activity of Av2 in C2H2-reduction assays. The kinetics of inactivation indicated that the minimum stoichiometry of NO to Av2 required to fully inactivate Av2 lies between 1 and 2. The rate of inactivation of Av2 activity by NO was stimulated up to 2-fold by the presence of MgATP and MgADP but was unaffected by the presence of sodium dithionite. Unexpectedly, complete inactivation of Av2 by low ratios of NO to Av2 also resulted in a complete loss of its ability to bind MgATP and MgADP. UV-visible spectroscopy indicated that the effect of NO on Av2 involves oxidation of the [4Fe-4S] center. EPR spectroscopy revealed that the loss of activity during inactivation of Av2 by NO correlated with the loss of the S = 1/2 and S = 3/2 signals. Appearance of the classical and intense iron-nitrosyl signal (g = 20.3) was only observed when Av2 was incubated with large molar excesses of NO and the appearance of this signal did not correlate with the loss of Av2 activity. The effects of NO on the MoFe protein (Av1) were more complex than for Av2. A time-dependent inactivation of Av1 activity (C2H2 reduction) was observed which required considerably higher concentrations of NO than those required to inactivate Av2 (up to 10 kPa).(ABSTRACT TRUNCATED AT 250 WORDS)}, number={11}, journal={Biochemistry}, author={Hyman, M. R. and Seefeldt, L. C. and Morgan, T. V. and Arp, D. J. and Mortenson, L. E.}, year={1992}, month={Mar}, pages={2947–2955} }
 @article{kinetic and spectroscopic analysis of the inactivating effects of nitric oxide on the individual components of azotobacter vinelandii nitrogenase._1992, DOI={10.1021/bi00126a015}, journal={Biochemistry}, year={1992}, month={Mar} }
 @article{rasche_hyman_arp_1991, title={Factors Limiting Aliphatic Chlorocarbon Degradation by Nitrosomonas europaea: Cometabolic Inactivation of Ammonia Monooxygenase and Substrate Specificity}, volume={57}, ISSN={0099-2240}, abstractNote={The soil nitrifying bacterium Nitrosomonas europaea is capable of degrading trichloroethylene (TCE) and other halogenated hydrocarbons. TCE cometabolism by N. europaea resulted in an irreversible loss of TCE biodegradative capacity, ammonia-oxidizing activity, and ammonia-dependent O(2) uptake by the cells. Inactivation was not observed in the presence of allylthiourea, a specific inhibitor of the enzyme ammonia monooxygenase, or under anaerobic conditions, indicating that the TCE-mediated inactivation required ammonia monooxygenase activity. When N. europaea cells were incubated with [C]TCE under conditions which allowed turnover of ammonia monooxygenase, a number of cellular proteins were covalently labeled with C. Treatment of cells with allylthiourea or acetylene prior to incubation with [C]TCE prevented incorporation of C into proteins. The ammonia-oxidizing activity of cells inactivated in the presence of TCE could be recovered through a process requiring de novo protein synthesis. In addition to TCE, a series of chlorinated methanes, ethanes, and other ethylenes were screened as substrates for ammonia monooxygenase and for their ability to inactivate the ammonia-oxidizing system of N. europaea. The chlorocarbons could be divided into three classes depending on their biodegradability and inactivating potential: (i) compounds which were not biodegradable by N. europaea and which had no toxic effect on the cells; (ii) compounds which were cooxidized by N. europaea and had little or no toxic effect on the cells; and (iii) compounds which were cooxidized and produced a turnover-dependent inactivation of ammonia oxidation by N. europaea.}, number={10}, journal={Applied and Environmental Microbiology}, author={Rasche, M. E. and Hyman, M. R. and Arp, D. J.}, year={1991}, month={Oct}, pages={2986–2994} }
 @article{factors limiting aliphatic chlorocarbon degradation by nitrosomonas europaea: cometabolic inactivation of ammonia monooxygenase and substrate specificity._1991, journal={Applied and environmental microbiology}, year={1991}, month={Oct} }
 @article{kinetic analysis of the interaction of nitric oxide with the membrane-associated, nickel and iron-sulfur-containing hydrogenase from azotobacter vinelandii._1991, DOI={10.1016/0167-4838(91)90261-w}, journal={Biochimica et biophysica acta}, year={1991}, month={Jan} }
 @article{hyman_arp_1991, title={Kinetic analysis of the interaction of nitric oxide with the nickel and iron-sulfur-containing membrane-bound hydrogenase from Azotobacter vinelandii}, volume={1076}, journal={Biochimica Biophysica Acta}, author={Hyman, M.R. and Arp, D. J.}, year={1991}, pages={167–174} }
 @article{rasche_hyman_arp_1990, title={Biodegradation of Halogenated Hydrocarbon Fumigants by Nitrifying Bacteria}, volume={56}, ISSN={1098-5336}, abstractNote={Three species of nitrifying bacteria were tested for the ability to degrade the halocarbon fumigants methyl bromide, 1,2-dichloropropane, and 1,2-dibromo-3-chloropropane. The soil nitrifiers Nitrosomonas europaea and Nitrosolobus multiformis degraded all three fumigants, while the marine nitrifier Nitrosococcus oceanus degraded only methyl bromide under the conditions tested. Inhibition of biodegradation by allylthiourea and acetylene, specific inhibitors of ammonia monooxygenase, suggests that ammonia monooxygenase is the enzyme which catalyzes fumigant degradation.}, number={8}, journal={Applied and Environmental Microbiology}, author={Rasche, Madeline E. and Hyman, Michael R. and Arp, Daniel J.}, year={1990}, month={Aug}, pages={2568–2571} }
 @article{hyman_kim_arp_1990, title={Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide}, volume={172}, ISSN={0021-9193}, abstractNote={Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined. Low concentrations of CS2 (less than 400 microM) produced a time-dependent inhibition of ammonia-dependent O2 uptake but did not inhibit hydrazine-oxidizing activity. CS2 also produced distinct changes in difference spectra of whole cells. These results suggest that ammonia monooxygenase (AMO) is the site of action of CS2. Unlike the case for thiourea and acetylene, saturating concentrations of CS2 did not fully inhibit AMO, and the inhibition resulted in a low but significant rate of ammonia-dependent O2 uptake. The effects of CS2 were not competitive with respect to ammonia concentration, and the inhibition by CS2 did not require the turnover of AMO to take effect. The ability of CS2-treated cells to incorporate [14C]acetylene into the 28-kilodalton polypeptide of AMO was used to demonstrate that the effects of CS2 are compatible with a mode of action which involves a reduction of the rate of turnover of AMO without effects on the catalytic mechanism. It is proposed that CS2 may act on AMO by reversibly reacting with a suitable nucleophilic amino acid in close proximity to the active site copper.}, number={9}, journal={Journal of Bacteriology}, author={Hyman, M. R. and Kim, C. Y. and Arp, D. J.}, year={1990}, month={Sep}, pages={4775–4782} }
 @article{inhibition of ammonia monooxygenase in nitrosomonas europaea by carbon disulfide._1990, DOI={10.1128/jb.172.9.4775-4782.1990}, journal={Journal of bacteriology}, year={1990}, month={Sep} }
 @article{rasche_hicks_hyman_arp_1990, title={Oxidation of monohalogenated ethanes and n-chlorinated alkanes by whole cells of Nitrosomonas europaea}, volume={172}, ISSN={0021-9193}, abstractNote={We have investigated the substrate specificity of ammonia monooxygenase in whole cells of the nitrifying bacterium Nitrosomonas europaea for a number of aliphatic halogenated hydrocarbons. To determine the effect of the halogen substituent and carbon chain length on substrate reactivity, we measured the rates of oxidation of the monohalogenated ethanes (fluoroethane, chloroethane, bromoethane, and iodoethane) and n-chlorinated C1 to C4 alkanes by whole cells of N. europaea. For monohalogenated ethanes, acetaldehyde was the major organic product and little or none of any of the alternate predicted products (2-halogenated alcohols) were detected. The maximum rate of haloethane oxidation increased with decreasing halogen molecular weight from iodoethane to chloroethane (19 to 221 nmol/min per mg of protein). In addition, the amount of substrate required for the highest rate of haloethane oxidation increased with decreasing halogen molecular weight. For the n-chlorinated alkanes, the rate of dechlorination, as measured by the appearance of the corresponding aldehyde product, was greatest for chloroethane and decreased dramatically for chloropropane and chlorobutane (118, 4, and 8 nmol of aldehyde formed per min per mg of protein, respectively). The concentration profiles for halocarbon oxidation by ammonia monooxygenase showed apparent substrate inhibition when ammonia was used as the reductant source. When hydrazine was used as the electron donor, no substrate inhibition was observed, suggesting that the inhibition resulted from reductant limitation.}, number={9}, journal={Journal of Bacteriology}, author={Rasche, M. E. and Hicks, R. E. and Hyman, M. R. and Arp, D. J.}, year={1990}, month={Sep}, pages={5368–5373} }
 @article{oxidation of monohalogenated ethanes and n-chlorinated alkanes by whole cells of nitrosomonas europaea._1990, DOI={10.1128/jb.172.9.5368-5373.1990}, journal={Journal of bacteriology}, year={1990}, month={Sep} }
 @article{hyman_arp_1990, title={The small-scale production of [U-14C] acetylene from Ba14C-CO3: Application to labelling of ammonia monooxygenase in autotrophic nitrifying bacteria}, volume={190}, journal={Analytical Biochemistry}, author={Hyman, M.R. and Arp, D.J.}, year={1990}, pages={348–353} }
 @article{the small-scale production of [u-14c]acetylene from ba14co3: application to labeling of ammonia monooxygenase in autotrophic nitrifying bacteria._1990, DOI={10.1016/0003-2697(90)90206-o}, journal={Analytical biochemistry}, year={1990}, month={Nov} }
 @article{hyman_ensign_arp_ludden_1989, title={Carbonyl sulfide inhibition of CO dehydrogenase from Rhodospirillum rubrum}, volume={28}, ISSN={0006-2960}, url={https://doi.org/10.1021/bi00443a007}, DOI={10.1021/bi00443a007}, number={17}, journal={Biochemistry}, author={Hyman, Michael R. and Ensign, Scott A. and Arp, Daniel J. and Ludden, Paul W.}, year={1989}, month={Aug}, pages={6821–6826} }
 @article{ensign_hyman_ludden_1989, title={Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide}, volume={28}, ISSN={0006-2960}, url={https://doi.org/10.1021/bi00438a011}, DOI={10.1021/bi00438a011}, number={12}, journal={Biochemistry}, author={Ensign, Scott A. and Hyman, Michael R. and Ludden, Paul W.}, year={1989}, month={Jun}, pages={4973–4979} }
 @article{hyman_arp_1988, title={Acetylene inhibition of metalloenzymes}, volume={173}, ISSN={0003-2697}, number={2}, journal={Analytical Biochemistry}, author={Hyman, M. R. and Arp, D. J.}, year={1988}, month={Sep}, pages={207–220} }
 @article{acetylene inhibition of metalloenzymes_1988, DOI={10.1016/0003-2697(88)90181-9}, journal={Analytical Biochemistry}, year={1988}, month={Sep} }
 @article{hyman_seefeldt_arp_1988, title={Aerobic, inactive forms of Azotobacter vinelandii hydrogenase: activation kinetics and insensitivity to C2H2 inhibition}, volume={957}, ISSN={0006-3002}, abstractNote={Azotobacter vinelandii hydrogenase (EC class 1.12), either purified or membrane-associated, was obtained aerobically in an inactive state. The kinetics of activation by treatment with a reductant (H2 or dithionite) were determined. Three distinct phases of the activation were observed. Aerobically prepared, inactive hydrogenase was insensitive to acetylene inhibition, but could be rendered acetylene-sensitive by reduction with dithionite. These findings indicate that acetylene inhibition of hydrogenase requires catalytically active enzyme.}, number={1}, journal={Biochimica Et Biophysica Acta}, author={Hyman, M. R. and Seefeldt, L. C. and Arp, D. J.}, year={1988}, month={Nov}, pages={91–96} }
 @article{aerobic, inactive forms of azotobacter vinelandii hydrogenase: activation kinetics and insensitivity to c2h2 inhibition._1988, DOI={10.1016/0167-4838(88)90160-4}, journal={Biochimica et biophysica acta}, year={1988}, month={Nov} }
 @article{hyman_murton_arp_1988, title={Interaction of Ammonia Monooxygenase from Nitrosomonas europaea with Alkanes, Alkenes, and Alkynes}, volume={54}, ISSN={0099-2240}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC204451/}, abstractNote={Ammonia monooxygenase of Nitrosomonas europaea catalyzes the oxidation of alkanes (up to C8) to alcohols and alkenes (up to C5) to epoxides and alcohols in the presence of ammonium ions. Straight-chain, N-terminal alkynes (up to C10) all exhibited a time-dependent inhibition of ammonia oxidation without effects on hydrazine oxidation.}, number={12}, journal={Applied and Environmental Microbiology}, author={Hyman, Michael R. and Murton, Ian B. and Arp, Daniel J.}, year={1988}, month={Dec}, pages={3187–3190} }
 @article{interaction of ammonia monooxygenase from nitrosomonas europaea with alkanes, alkenes, and alkynes._1988, journal={Applied and environmental microbiology}, year={1988}, month={Dec} }
 @article{hyman_arp_1988, title={Reversible and irreversible effects of nitric oxide on the soluble hydrogenase from Alcaligenes eutrophus H16}, volume={254}, ISSN={0264-6021, 1470-8728}, url={http://www.biochemj.org/content/254/2/469}, DOI={10.1042/bj2540469}, abstractNote={The effects of NO on the H2-oxidizing and diaphorase activities of the soluble hydrogenase from Alcaligenes eutrophus H16 were investigated. With fully activated enzyme, NO (8-150 nM in solution) inhibited H2 oxidation in a time- and NO-concentration-dependent process. Neither H2 nor NAD+ appeared to protect the enzyme against the inhibition. Loss of activity in the absence of an electron acceptor was about 10 times slower than under turnover conditions. The inhibition was partially reversible; approx. 50% of full activity was recoverable after removal of the NO. Recovery was slower in the absence of an electron acceptor than in the presence of H2 plus an electron acceptor. The diaphorase activity of the unactivated hydrogenase was not affected by NO concentrations of up to 200 microM in solution. Exposure of the unactivated hydrogenase to NO irreversibly inhibited the ability of the enzyme to be fully activated for H2-oxidizing activity. The enzyme also lost its ability to respond to H2 during activation in the presence of NADH. The results are interpreted in terms of a complex inhibition that displays elements of (1) a reversible slow-binding inhibition of H2-oxidizing activity, (2) an irreversible effect on H2-oxidizing activity and (30 an irreversible inhibition of a regulatory component of the enzyme. Possible sites of action for NO are discussed.}, number={2}, journal={Biochemical Journal}, author={Hyman, M. R. and Arp, D. J.}, year={1988}, month={Sep}, pages={469–475} }
 @article{hyman_fox_arp_1988, title={Role of hydrogen in the activation and regulation of hydrogen oxidation by the soluble hydrogenase from Alcaligenes eutrophus H16}, volume={254}, ISSN={0264-6021}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1135100/}, abstractNote={The activation kinetics of the H2-oxidizing activity of the soluble hydrogenase from Alcaligenes eutrophus H16 were investigated. Activation with Na2S2O4 plus 101 kPa H2 resulted in a rapid increase in activity over 1 h and constant activity after 3 h incubation. Less-stable activations were achieved if enzyme was incubated with Na2S2O4 under 1 kPa H2 or 101 kPa N2. The enzyme could also be partly activated either with NADH alone or with H2 alone. The level of activity obtained with both 101 kPa H2 and NADH present was greater than that obtained with either 101 kPa H2 or NADH alone. Activation with H2 plus NADH was virtually independent of NADH concentration but highly dependent on H2 concentration. The effects of various concentrations of H2 and constant concentration of NADH on the level of activation were the same whether H2 oxidation was assayed by H2-dependent Methylene Blue or NAD+ reduction. Diaphorase activity did not require activation and was little affected by the treatments that activated H2-oxidizing activity. The results suggest that H2 plays an important role in regulating the level of H2-oxidizing activity in this soluble hydrogenase.}, number={2}, journal={Biochemical Journal}, author={Hyman, M R and Fox, C A and Arp, D J}, year={1988}, month={Sep}, pages={463–468} }
 @article{role of hydrogen in the activation and regulation of hydrogen oxidation by the soluble hydrogenase from alcaligenes eutrophus h16._1988, DOI={10.1042/bj2540463}, journal={The Biochemical journal}, year={1988}, month={Sep} }
 @article{hyman_arp_1987, title={Acetylene is an active-site-directed, slow-binding, reversible inhibitor of Azotobacter vinelandii hydrogenase}, volume={26}, ISSN={0006-2960}, url={https://doi.org/10.1021/bi00394a023}, DOI={10.1021/bi00394a023}, number={20}, journal={Biochemistry}, author={Hyman, Michael R. and Arp, Daniel J.}, year={1987}, month={Oct}, pages={6447–6454} }
 @article{hyman_arp_1987, title={Quantification and removal of some contaminating gases from acetylene used to study gas-utilizing enzymes and microorganisms}, volume={53}, ISSN={0099-2240}, abstractNote={Acetylene generated from various grades of calcium carbide and obtained from commercial- and purified-grade acetylene cylinders was shown to contain high concentrations of various contaminants. Dependent on the source of acetylene, these included, at maximal values, H(2) (0.023%), O(2) (0.779%), N(2) (3.78%), PH(3) (0.06%), CH(4) (0.073%), and acetone (1 to 10%). The concentration of the contaminants in cylinder acetylene was highly dependent on the extent of cylinder discharge. Several conventional methods used to partially purify cylinder acetylene were compared. A small-scale method for extensively purifying acetylene is described. An effect of acetylene quality on acetylene reduction assays conducted with purified nitrogenase from Azotobacter vinelandii was demonstrated.}, number={2}, journal={Applied and Environmental Microbiology}, author={Hyman, M. R. and Arp, D. J.}, year={1987}, month={Feb}, pages={298–303} }
 @article{quantification and removal of some contaminating gases from acetylene used to study gas-utilizing enzymes and microorganisms._1987, journal={Applied and environmental microbiology}, year={1987}, month={Feb} }
 @article{hyman_sansome-smith_shears_wood_1985, title={A kinetic study of benzene oxidation to phenol by whole cells of Nitrosomonas europaea and evidence for the further oxidation of phenol to hydroquinone}, volume={143}, ISSN={1432-072X}, url={https://doi.org/10.1007/BF00411254}, DOI={10.1007/BF00411254}, abstractNote={The oxidation of benzene to phenol by whole cells of Nitrosomonas europaea is catalysed by ammonia monooxygenase, and therefore requires a source of reducing power. Endogenous substrates, hydrazine, hydroxylamine and ammonium ions were compared as reductants. The highest rates of benzene oxidation were obtained with 4 mM benzene and hydrazine as reductant, and equalled 6 μmol· h-1·mg protein-1. The specificity of ammonia monooxygenase for benzene as a substrate was determined by measuring kcat/Km for benzene relative to kcat/Km for uncharged ammonia, a value of 0.4 being obtained. Phenol was found to be further hydroxylated to yield hydroquinone. This reaction, like benzene oxidation, was sensitive to the ammonia monooxygenase inhibitor allylthiourea. Catechol and resorcinol were not detected as products of phenol oxidation, implying that at least 88% of the hydroxylation is para-directed.}, number={3}, journal={Archives of Microbiology}, author={Hyman, Michael R. and Sansome-Smith, Alastair W. and Shears, Jeremy H. and Wood, Paul M.}, year={1985}, month={Dec}, pages={302–306} }
 @article{hyman_wood_1985, title={Suicidal inactivation and labelling of ammonia mono-oxygenase by acetylene.}, volume={227}, ISSN={0264-6021}, url={https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1144898/}, abstractNote={Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea. High NH4+ ion concentrations were protective. The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. If acetylene was added in the absence of O2, the cells remained active until O2 was re-introduced. A protective effect was also demonstrated with thiourea, a reversible non-competitive inhibitor of ammonia oxidation. Incubation of cells with [14C]acetylene was found to cause labelling of a single membrane polypeptide. This ran on dodecyl sulphate/polyacrylamide-gel electrophoresis with an Mr value of 28 000. It is concluded that acetylene is a suicide substrate for the mono-oxygenase. The labelling experiment provides the first identification of a constituent polypeptide of ammonia mono-oxygenase.}, number={3}, journal={Biochemical Journal}, author={Hyman, M R and Wood, P M}, year={1985}, month={May}, pages={719–725} }
 @article{suicidal inactivation and labelling of ammonia mono-oxygenase by acetylene._1985, DOI={10.1042/bj2270719}, journal={The Biochemical journal}, year={1985}, month={May} }
 @inbook{bromocarbon oxidation by nitrosomonas europaea_1984, booktitle={Microbial Growth on C1 Compounds}, year={1984} }
 @article{hyman_wood_1984, title={Ethylene oxidation by Nitrosomonas europaea}, volume={137}, ISSN={1432-072X}, url={https://doi.org/10.1007/BF00414458}, DOI={10.1007/BF00414458}, abstractNote={Incubation of whole cells of the nitrifying bacterium Nitrosomonas europaea with ethylene led to the formation of ethylene oxide. Ethylene oxide production was prevented by inhibitors of ammonium ion oxidation, and showed properties implying that ethylene is a substrate for the ammonia oxidising enzyme, ammonia monooxygenase. Endogenous substrates, hydroxylamine, hydrazine and ammonium ions were compared as sources of reducing power in terms of rates and stoichiometries of ethylene oxidation. The highest rates of ethylene oxide formation (15 μmol h-1 mg protein-1) were obtained with hydrazine as donor. The data suggest that at high concentrations of ethylene the rate of oxidation is limited by the rate at which reducing power can be supplied to the monooxygenase, not by an intrinsic Vmax. Ethylene had an inhibitory effect on the rate of ammonium ion utilisation; an approximate Ki of 80 μM was derived, but the results deviated from simple competitive behaviour. Measurement of relative rates of ethylene oxide formation and ammonium ion utilization led to a kcat/Km value for ethylene of 1.1 relative to NH 4 + , or 0.04 relative to the true natural substrate, NH3. The effects of higher concentrations of ethylene oxide on oxygen uptake rates were also investigated. The results imply that ethylene oxide is also a substrate for the monooxygenase, but with a much lower affinity than ethylene.}, number={2}, journal={Archives of Microbiology}, author={Hyman, Michael R. and Wood, Paul M.}, year={1984}, month={Feb}, pages={155–158} }
 @article{hyman_wood_1983, title={Methane oxidation by Nitrosomonas europaea}, volume={212}, ISSN={0264-6021}, abstractNote={Methane inhibited NH4+ utilization by Nitrosomonas europaea with a Ki of 2mM. O2 consumption was not inhibited. In the absence of NH4+, or with hydrazine as reductant, methane caused nearly a doubling in the rate of O2 uptake. The stimulation was abolished by allylthiourea, a sensitive inhibitor of the oxidation of NH4+. Analysis revealed that methanol was being formed in these experiments, with yields approaching 1 mol of methanol per mol of O2 consumed under certain conditions. When cells were incubated with NH4+ under an atmosphere of 50% methane, 50 microM-methanol was generated in 1 h. It is concluded that methane is an alternative substrate for the NH3-oxidizing enzyme (ammonia mono-oxygenase),m albeit with a much lower affinity than for methane mono-oxygenase of methanotrophs.}, number={1}, journal={The Biochemical Journal}, author={Hyman, M. R. and Wood, P. M.}, year={1983}, month={Apr}, pages={31–37} }
 @article{methane oxidation by nitrosomonas europaea._1983, DOI={10.1042/bj2120031}, journal={The Biochemical journal}, year={1983}, month={Apr} }
 @article{ensign_hyman_ludden, title={Nickel-specific, slow-binding inhibition of carbon monoxide dehydrogenase from Rhodospirillum rubrum by cyanide}, volume={28}, journal={Biochemistry}, author={Ensign, S.A. and Hyman, M.R. and Ludden, P.W.}, pages={4973–4979} }