TY - CHAP TI - An Evolutionary Perspective of Phosphoinositide Signaling During Osmotic Stress AU - Heilmann, I. AU - Perera, I.Y. AU - Boss, W.F. T2 - Intracellular Signalling in Plant and Animal Systems A2 - Kravets, V. PY - 2002/// ER - TY - JOUR TI - Effect of short-term N2 deficiency on expression of the ureide pathway in cowpea root nodules AU - Smith, P.M.C. AU - Winter, H. AU - Storer, P.J. AU - Bussell, J.D. AU - Schuller, K.A. AU - Atkins, C.A. T2 - Plant Physiology AB - Root systems of 28-d-old cowpea (Vigna unguiculata L. Walp cv Vita 3: Bradyrhizobium sp. strain CB756) plants bearing nitrogen-fixing nodules in sand culture were exposed to an atmosphere of Ar:O(2) (80:20, v/v) for 48 h and then returned to air. Root systems of control plants were maintained in air throughout. Nodules were harvested at the same times in control and Ar:O(2)-treated root systems. Activities of two enzymes of de novo purine synthesis, glycinamide ribonucleotide transformylase (GART; EC 2.1.2.2), aminoimidazole ribonucleotide synthetase (AIRS; EC 6.3.3.1), uricase (EC 1.7.3.3), and phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) were measured together with the protein level of each using immune-specific polyclonal antibodies. AIRS activity and protein both declined to very low levels within 6 h in Ar:O(2) together with a decline in transcript level of pur5, the encoding gene. GART activity, protein, and transcript (pur3) levels were relatively stable. Uricase activity declined in Ar:O(2) as rapidly as AIRS activity but the protein was stable. PEPC activity showed evidence of increased sensitivity to inhibition by malate but the protein level was stable. The data indicate that the flux of fixed N from bacteroids (N(2)-fixing nodule bacteria) is in some way associated with transcriptional control over pur5 and possibly also catabolism of AIRS protein. In contrast, there is limited posttranslational control over GART and PEPC and close posttranslational control over uricase activity. The significance of these different levels of regulation is discussed in relation to the overall control of enhanced expression of plant enzymes in the cowpea symbiosis. DA - 2002/// PY - 2002/// DO - 10.1104/pp.010714 VL - 129 IS - 3 SP - 1216-1221 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0035983935&partnerID=MN8TOARS ER - TY - JOUR TI - Agrobacterium-mediated genetic transformation of Acacia mangium AU - Xie, D. AU - Hong, Y. T2 - Plant Cell Reports DA - 2002/3// PY - 2002/3// DO - 10.1007/s00299-001-0397-9 VL - 20 IS - 10 SP - 917-922 J2 - Plant Cell Rep LA - en OP - SN - 0721-7714 1432-203X UR - http://dx.doi.org/10.1007/s00299-001-0397-9 DB - Crossref KW - Acacia mangium KW - Agrobacterium KW - genetic transformation KW - rejuvenation ER - TY - JOUR TI - Cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, Nitrosomonas europaea. T2 - Biodegradation DA - 2002/1/1/ PY - 2002/1/1/ DO - 10.1023/a:1022811430030 UR - https://doi.org/10.1023/a:1022811430030 ER - TY - JOUR TI - Phase variation of the gonococcal siderophore receptor FetA AU - Carson, Susan D. Biegel AU - Stone, Barbara AU - Beucher, Margaret AU - Fu, Jennifer AU - Sparling, P. Frederick T2 - Molecular Microbiology AB - FetA, the recently characterized gonococcal ferric enterobactin receptor, exhibited extremely rapid phase variation between high‐ and low‐expression levels. The frequency of phase variation was ≈ 1.3% in both directions in gonococcal strain FA1090. FetA expression in the ‘high phase’ was significantly greater than the level of expression in the ‘low phase’. Expression levels correlated with the number of cytosine residues in a string of cytosines located close to the transcriptional start site for fetA between the putative −10 and −35 consensus sequences. Antibody production against FetA commonly occurs in infected patients, and we therefore hypothesize that phase variation reflects a balance between the advantages of being able to use a ferric siderophore as an iron source and evasion of the host immune response. DA - 2002/1/18/ PY - 2002/1/18/ DO - 10.1046/j.1365-2958.2000.01873.x VL - 36 IS - 3 SP - 585-593 LA - en OP - SN - 0950-382X 1365-2958 UR - http://dx.doi.org/10.1046/j.1365-2958.2000.01873.x DB - Crossref ER - TY - JOUR TI - Trp-dependent auxin biosynthesis in Arabidopsis: involvement of cytochrome P450s CYP79B2 and CYP79B3 AU - Zhao, Yunde AU - Hull, Anna K. AU - Gupta, Neeru R. AU - Goss, Kendrick A. AU - Alonso, José AU - Ecker, Joseph R. AU - Normanly, Jennifer AU - Chory, Joanne AU - Celenza, John L. T2 - Genes & Development DA - 2002/// PY - 2002/// VL - 16 IS - 23 SP - 3100-3112 ER - TY - JOUR TI - Three redundant brassinosteroid early response genes encode putative bHLH transcription factors required for normal growth AU - Friedrichsen, Danielle M. AU - Nemhauser, Jennifer AU - Muramitsu, Takamichi AU - Maloof, Julin N. AU - Alonso, José AU - Ecker, Joseph R. AU - Furuya, Masaki AU - Chory, Joanne T2 - Genetics DA - 2002/// PY - 2002/// VL - 162 IS - 3 SP - 1445-1456 ER - TY - JOUR TI - NPSN11 is a cell plate-associated SNARE protein that interacts with the syntaxin KNOLLE AU - Zheng, Haiyan AU - Bednarek, Sebastian Y. AU - Sanderfoot, Anton A. AU - Alonso, Jose AU - Ecker, Joseph R. AU - Raikhel, Natasha V. T2 - Plant physiology DA - 2002/// PY - 2002/// VL - 129 IS - 2 SP - 530-539 ER - TY - JOUR TI - De-Etiolated 1 and Damaged DNA Binding Protein 1 Interact to Regulate< i> Arabidopsis Photomorphogenesis AU - Schroeder, Dana F. AU - Gahrtz, Manfred AU - Maxwell, Bridey B. AU - Cook, R. Kimberley AU - Kan, Jack M. AU - Alonso, José M. AU - Ecker, Joseph R. AU - Chory, Joanne T2 - Current Biology DA - 2002/// PY - 2002/// VL - 12 IS - 17 SP - 1462-1472 ER - TY - JOUR TI - A role for peroxisomes in photomorphogenesis and development of Arabidopsis AU - Hu, Jianping AU - Aguirre, Maria AU - Peto, Charles AU - Alonso, José AU - Ecker, Joseph AU - Chory, Joanne T2 - Science DA - 2002/// PY - 2002/// VL - 297 IS - 5580 SP - 405-409 ER - TY - JOUR TI - Molecular characterization of AtNAM: a member of the Arabidopsis NAC domain superfamily AU - Duval, Manuel AU - Hsieh, Tzung-Fu AU - Kim, Soo Young AU - Thomas, Terry L. T2 - Plant Molecular Biology DA - 2002/// PY - 2002/// DO - 10.1023/a:1016028530943 VL - 50 IS - 2 SP - 237-248 SN - 0167-4412 UR - http://dx.doi.org/10.1023/A:1016028530943 KW - DNA-binding domain KW - shoot meristem KW - transcriptional activation ER - TY - JOUR TI - When a day makes a difference. Interpreting data from endoplasmic reticulum-targeted green fluorescent protein fusions in cells grown in suspension culture AU - Persson, S. AU - Love, J. AU - Tsou, P. L. AU - Robertson, D. AU - Thompson, William AU - Boss, W. F. T2 - Plant Physiology DA - 2002/// PY - 2002/// DO - 10.1104 VL - 128 IS - 2 SP - 341–344 ER - TY - JOUR TI - pH regulation of enzyme production in Aspergillus nidulans growing in aerobic batch fermenter. T2 - Biotechnology letters DA - 2002/4// PY - 2002/4// DO - 10.1023/a:1014868726188 VL - 4 IS - 7 SP - 567-572 UR - http://europepmc.org/abstract/AGR/IND23282191 KW - Aspergillus nidulans KW - enzymes production KW - fungi KW - regulation of expression ER - TY - JOUR TI - SEUSS, a member of a novel family of plant regulatory proteins, represses floral homeotic gene expression with LEUNIG. AU - Franks, R.G. AU - Wang, C. AU - Levin, J.Z. AU - Liu, Z. AU - Development DA - 2002/1// PY - 2002/1// VL - 129 IS - 1 SP - 253–263 UR - http://europepmc.org/abstract/med/11782418 ER - TY - JOUR TI - SEUSS, a member of a novel family of plant regulatory proteins, represses floral homeotic gene expression with LEUNIG AU - Franks, R.G. AU - Wang, C. AU - Levin, J.Z. AU - Liu, Z. T2 - Development DA - 2002/// PY - 2002/// VL - 129 IS - 1 SP - 253-263 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036333380&partnerID=MN8TOARS ER - TY - JOUR TI - Determining critical pre- and post-anthesis periods and physiological processes in Lycopersicon esculentum Mill. exposed to moderately elevated temperatures AU - Sato, S AU - Peet, MM AU - Thomas, JF T2 - JOURNAL OF EXPERIMENTAL BOTANY AB - To determine the thermosensitive periods and physiological processes in tomato flowers exposed to moderately elevated temperatures, tomato plants (Lycopersicon esculentum Mill., cv. NC 8288) were grown at 28/22 degrees C or 32/26 degrees C day/night temperature regimes and then transferred to the opposite regime for 0-15 d before or 0-24 h after anthesis. For plants initially grown at 28/22 degrees C, moderate temperature stress before anthesis decreased the percentage of fruit set per plant, but did not clarify the thermosensitive period. The same level of stress did not significantly reduce fruit set when applied immediately after anthesis. For plants initially grown at 32/26 degrees C, fruit set was completely prevented unless a relief period of more than 5 d was provided before anthesis. The same level of stress relief for 3-24 h after anthesis also increased fruit set. Plants were most sensitive to 32/26 degrees C temperatures 7-15 d before anthesis. Microscopic investigation of anthers in plants grown continuously at high temperature indicated disruption of development in the pollen, endothecium, epidermis, and stomium. This disruption was reduced, but still observable in plants relieved from high temperature for 10 d before anthesis. DA - 2002/5// PY - 2002/5// DO - 10.1093/jexbot/53.371.1187 VL - 53 IS - 371 SP - 1187-1195 SN - 0022-0957 KW - anther KW - fruit set KW - global warming KW - heat tolerance KW - male reproductive structures KW - microsporogenesis KW - pollen temperature-sensitive period KW - thermotolerance ER - TY - JOUR TI - Nags Head Woods collections of the National Park Service Cape Hatteras National Seashore herbarium (CAHA) AU - Krings, A. T2 - Journal of the North Carolina Academy of Science DA - 2002/// PY - 2002/// VL - 118 IS - 3 SP - 145-155 ER - TY - JOUR TI - Floral variation and diagnosis of Richardia (Rubiaceae) in the Carolinas AU - Krings, A. T2 - Castanea DA - 2002/// PY - 2002/// VL - 67 IS - 3 SP - 329-330 ER - TY - JOUR TI - Additions to the flora of Nags Head Woods (Dare County, North Carolina) and the Outer Banks of North Carolina AU - Krings, A. T2 - SIDA, Contributions To Botany DA - 2002/// PY - 2002/// VL - 20 IS - 2 SP - 839-843 ER - TY - JOUR TI - Keys to the vines of Carolina wetlands AU - Krings, A. T2 - Vulpia DA - 2002/// PY - 2002/// VL - 1 SP - 23-40 ER - TY - JOUR TI - Cultivated, dicotyledonous taxa at the North Carolina State University herbarium AU - Krings, A. T2 - Vulpia DA - 2002/// PY - 2002/// VL - 1 SP - 133-156 ER - TY - JOUR TI - Commelina benghalensis (Commelinaceae) new to North Carolina and an updated key to Carolina congeners AU - Krings, A. AU - Burton, M. G. AU - York, A. C. T2 - SIDA, Contributions To Botany DA - 2002/// PY - 2002/// VL - 20 IS - 1 SP - 419-422 ER - TY - JOUR TI - Cirsium nuttallii (Asteraceae: Cynareae): New to North Carolina and an illustrated key to southeastern congeners AU - Krings, A. AU - Westbrooks, R. AU - Lloyd, J. T2 - SIDA, Contributions To Botany DA - 2002/// PY - 2002/// VL - 20 IS - 2 SP - 845-848 ER - TY - JOUR TI - A new species of Gonolobus (Apocynaceae: Asclepiadeae, Gonolobinae) from southern Costa Rica AU - Krings, A. T2 - SIDA, Contributions To Botany DA - 2002/// PY - 2002/// VL - 20 IS - 1 SP - 105-108 ER - TY - JOUR TI - High-throughput transgene copy number estimation by competitive PCR AU - Callaway, AS AU - Abranches, R AU - Scroggs, J AU - Allen, GC AU - Thompson, WF T2 - PLANT MOLECULAR BIOLOGY REPORTER DA - 2002/9// PY - 2002/9// DO - 10.1007/BF02782462 VL - 20 IS - 3 SP - 265-277 SN - 0735-9640 KW - competitive KW - copy number KW - high throughput KW - PCR KW - quantitative KW - transgenic ER - TY - CHAP TI - An appendix on scientific nomenclature AU - Hardin, J. W. T2 - The natural gardens of North Carolina (Rev. ed.) CN - QK178 .W4 2002 PY - 2002/// SP - 209-221 PB - Chapel Hill, University of North Carolina Press SN - 0807826677 ER - TY - JOUR TI - Cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, Nitrosomonas europaea AU - Chang, S. W. AU - Hyman, M. R. AU - Williamson, K. J. T2 - Biodegradation (Dordrecht) DA - 2002/// PY - 2002/// VL - 13 IS - 6 SP - 373-381 ER - TY - JOUR TI - Mutations in the gravity persistence signal loci in arabidopsis disrupt the perception and/or signal transduction of gravitropic stimuli AU - Wyatt, SE AU - Rashotte, AM AU - Shipp, MJ AU - Robertson, D AU - Muday, GK T2 - PLANT PHYSIOLOGY AB - Gravity plays a fundamental role in plant growth and development, yet little is understood about the early events of gravitropism. To identify genes affected in the signal perception and/or transduction phase of the gravity response, a mutant screen was devised using cold treatment to delay the gravity response of inflorescence stems of Arabidopsis. Inflorescence stems of Arabidopsis show no response to gravistimulation at 4 degrees C for up to 3 h. However, when gravistimulated at 4 degrees C and then returned to vertical at room temperature (RT), stems bend in response to the previous, horizontal gravistimulation (H. Fukaki, H. Fujisawa, M. Tasaka [1996] Plant Physiology 110: 933-943). This indicates that gravity perception, but not the gravitropic response, occurs at 4 degrees C. Recessive mutations were identified at three loci using this cold effect on gravitropism to screen for gravity persistence signal (gps) mutants. All three mutants had an altered response after gravistimulation at 4 degrees C, yet had phenotypically normal responses to stimulations at RT. gps1-1 did not bend in response to the 4 degrees C gravity stimulus upon return to RT. gps2-1 responded to the 4 degrees C stimulus but bent in the opposite direction. gps3-1 over-responded after return to RT, continuing to bend to an angle greater than wild-type plants. At 4 degrees C, starch-containing statoliths sedimented normally in both wild-type and the gps mutants, but auxin transport was abolished at 4 degrees C. These results are consistent with GPS loci affecting an aspect of the gravity signal perception/transduction pathway that occurs after statolith sedimentation, but before auxin transport. DA - 2002/11// PY - 2002/11// DO - 10.1104/pp.102.010579 VL - 130 IS - 3 SP - 1426-1435 SN - 1532-2548 ER - TY - JOUR TI - Constitutive expression of a celery mannitol dehydrogenase in tobacco enhances resistance to the mannitol-secreting fungal pathogen Alternaria alternata AU - Jennings, DB AU - Daub, ME AU - Pharr, DM AU - Williamson, JD T2 - PLANT JOURNAL AB - Our previous observation that host plant extracts induce production and secretion of mannitol in the tobacco pathogen Alternaria alternata suggested that, like their animal counterparts, plant pathogenic fungi might produce the reactive oxygen quencher mannitol as a means of suppressing reactive oxygen-mediated plant defenses. The concurrent discovery that pathogen attack induced mannitol dehydrogenase (MTD) expression in the non-mannitol-containing host tobacco suggested that plants, unlike animals, might be able to counter this fungal suppressive mechanism by catabolizing mannitol of fungal origin. To test this hypothesis, transgenic tobacco plants constitutively expressing a celery Mtd cDNA were produced and evaluated for potential changes in resistance to both mannitol- and non-mannitol-secreting pathogens. Constitutive expression of the MTD transgene was found to confer significantly enhanced resistance to A. alternata, but not to the non-mannitol-secreting fungal pathogen Cercospora nicotianae. These results are consistent with the hypothesis that MTD plays a role in resistance to mannitol-secreting fungal plant pathogens. DA - 2002/10// PY - 2002/10// DO - 10.1046/j.1365-313X.2001.01399.x VL - 32 IS - 1 SP - 41-49 SN - 0960-7412 KW - antioxidant KW - disease resistance KW - hydroxyl radical KW - mannitol KW - reactive oxygen ER - TY - JOUR TI - Reproductive abnormalities in glyphosate-resistant cotton caused by lower CP4-EPSPS levels in the male reproductive tissue AU - Pline, WA AU - Viator, R AU - Wilcut, JW AU - Edmisten, KL AU - Thomas, J AU - Wells, R T2 - WEED SCIENCE AB - Glyphosate treatments to glyphosate-resistant (GR) cotton have been associated with poor pollination and increased boll abortion. Anatomical studies were conducted to characterize the effect of glyphosate treatments on the development of male and female reproductive organs of cotton flowers at anthesis. In comparison with nontreated plants, glyphosate applied at both the four-leaf stage postemergence (POST) and at the eight-leaf stage POST directed inhibited the elongation of the staminal column and filament, which increased the distance from the anthers to the receptive stigma tip by 4.9 to 5.7 mm during the first week of flowering. The increased distance from the anthers to the stigma resulted in 42% less pollen deposited on stigmas of glyphosate-treated plants than in nontreated plants. Moreover, pollen from glyphosate-treated plants showed numerous morphological abnormalities. Transmission electron microscopy showed the presence of large vacuoles, numerous starch grains, and less organized pockets of the endoplasmic reticulum containing fewer ribosomes in pollen from glyphosate-treated plants than from nontreated plants. Pollen development in glyphosate-treated plants is likely inhibited or aborted at the vacuolate microspore and vacuolate microgamete stages of microgametogenesis, resulting in immature pollen at anthesis. Although stigmas from glyphosate-treated plants were 1.2 to 1.4 mm longer than those from nontreated plants, no other anatomical differences in stigmas were visibly evident. The presence of the GR 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) enzyme from Agrobacterium sp. strain CP4 was quantified in reproductive and vegetative tissues using enzyme-linked immunosorbent assay. The content of CP4-EPSPS in the stigma, anther, preanthesis floral bud (square), and flower petals was significantly less than that in the vegetative leaf tissue. Glyphosate effects on the male reproductive development resulting in poor pollen deposition on the stigma, as well as production of aborted pollen with reduced viability, provide a likely explanation for reports of increased boll abortion and pollination problems in glyphosate-treated GR cotton. DA - 2002/// PY - 2002/// DO - 10.1614/0043-1745(2002)050[0438:RAIGRC]2.0.CO;2 VL - 50 IS - 4 SP - 438-447 SN - 0043-1745 KW - herbicide-resistant crops KW - transgenic crops KW - gametogenesis KW - male sterile KW - ELISA KW - pollen KW - anther ER - TY - JOUR TI - Purification and characterization of the major isotypes of apyrase from the cytoskeleton fraction in Pisum sativum AU - Abe, S AU - Moustafa, MFM AU - Shibata, K AU - Yoneda, M AU - Davies, E T2 - PLANT PHYSIOLOGY AND BIOCHEMISTRY AB - We isolated isotypes of the 49-kDa apyrase from the cytoskeleton fraction of pea (Pisum sativum L. var. Alaska) stems, separated them using heparin affinity and anion exchange column chromatography, and investigated the enzymatic activities of each isotype. When potassium acetate gradients at constant pH were employed, there was poor separation between isotypes. However, when a pH gradient of 6.7–8.5 was used in conjunction with a potassium acetate gradient from 0 to 1 M, five peaks were identifiable, eluting between 0.35 and 0.65 M potassium acetate, and termed P0, P1, P2, P3, and P4. 2D-Polyacrylamide gel electrophoresis showed that each of these peaks was highly enriched for an individual isotype, and the isoelectric points of these isotypes were 5.82, 6.05, 6.30, 6.55, and 6.80 in fractions P0, P1, P2, P3, and P4, respectively. The isotypes of pI 6.05, 6.30, and 6.55 were the most abundant, and the more acidic isotypes had slightly higher molecular mass than other isotypes. Based on their partial amino acid sequences, their capability to hydrolyze both nucleoside tri- and di-phosphates into their respective mono-phosphates, and their similar hydrolyzing activity towards ADP, we presume they are all isotypes of the 49-kDa apyrase (EC 3.6.1.5). Since the calculated isoelectric point of apyrase based upon its amino acid sequence is 7.11, these results indicate that the enzyme is modified in various ways (most likely including phosphorylation) to furnish different isoforms with different activities over different substrates. DA - 2002/12// PY - 2002/12// DO - 10.1016/S0981-9428(02)01466-3 VL - 40 IS - 12 SP - 1019-1023 SN - 0981-9428 KW - apyrase KW - cytoskeleton KW - 2D-PAGE KW - hydrolysis KW - isoelectric point KW - phosphorylation KW - Pisum sativum ER - TY - PCOMM TI - Correspondence re: A. H. Ree et al., expression of a novel factor in human breast cancer cells with metastatic potential. Cancer Res., 59: 4675-4680, 1999 AU - Coker, J. S. AU - Davies, E. DA - 2002/// PY - 2002/// SP - 4164-4165 ER - TY - JOUR TI - Expression of the high capacity calcium-binding domain of calreticulin increases bioavailable calcium stores in plants AU - Wyatt, SE AU - Tsou, PL AU - Robertson, D T2 - TRANSGENIC RESEARCH DA - 2002/2// PY - 2002/2// DO - 10.1023/A:1013917701701 VL - 11 IS - 1 SP - 1-10 SN - 1573-9368 KW - Arabidopsis KW - calreticulin KW - calcium-binding KW - calcium storage KW - endoplasmic reticulum KW - environmental stress ER - TY - JOUR TI - Two E2F elements regulate the proliferating cell nuclear antigen promoter differently during leaf development AU - Egelkrout, EM AU - Mariconti, L AU - Settlage, SB AU - Cella, R AU - Robertson, D AU - Hanley-Bowdoin, L T2 - PLANT CELL AB - E2F transcription factors regulate genes expressed at the G1/S boundary of the cell division cycle in higher eukaryotes. Although animal E2F proteins and their target promoters have been studied extensively, little is known about how these factors regulate plant promoters. An earlier study identified two E2F consensus binding sites in the promoter of a Nicotiana benthamiana gene encoding proliferating cell nuclear antigen (PCNA) and showed that the proximal element (E2F2) is required for the full repression of PCNA expression in mature leaves. In this study, we examined the distal element (E2F1) and how it interacts with the E2F2 site to regulate the PCNA promoter. Gel shift assays using plant nuclear extracts or purified Arabidopsis E2F and DP proteins showed that different complexes bind to the two E2F sites. Mutation of the E2F1 site or both sites differentially altered PCNA promoter function in transgenic plants. As reported previously for the E2F2 mutation, the E2F1 and E2F1+2 mutations partially relieved the repression of the PCNA promoter in mature leaves. In young tissues, the E2F1 mutation resulted in a threefold reduction in PCNA promoter activity, whereas the E2F1+2 mutation had no detectable effect. The activity of E2F1+2 mutants was indistinguishable from that of E2F2 mutants. These results demonstrate that both E2F elements contribute to the repression of the PCNA promoter in mature leaves, whereas the E2F1 site counters the repression activity of the E2F2 element in young leaves. DA - 2002/12// PY - 2002/12// DO - 10.1105/tpc.006403 VL - 14 IS - 12 SP - 3225-3236 SN - 1040-4651 ER - TY - JOUR TI - Host DNA replication is induced by geminivirus infection of differentiated plant cells AU - Nagara, S AU - Hanley-Bowdoin, L AU - Robertson, D T2 - PLANT CELL AB - The geminivirus Tomato golden mosaic virus (TGMV) replicates in differentiated plant cells using host DNA synthesis machinery. We used 5-bromo-2-deoxyuridine (BrdU) incorporation to examine DNA synthesis directly in infected Nicotiana benthamiana plants to determine if viral reprogramming of host replication controls had an impact on host DNA replication. Immunoblot analysis revealed that up to 17-fold more BrdU was incorporated into chromosomal DNA of TGMV-infected versus mock-infected, similarly treated healthy leaves. Colocalization studies of viral DNA and BrdU demonstrated that BrdU incorporation was specific to infected cells and was associated with both host and viral DNA. TGMV and host DNA synthesis were inhibited differentially by aphidicolin but were equally sensitive to hydroxyurea. Short BrdU labeling times resulted in some infected cells showing punctate foci associated with host DNA. Longer periods showed BrdU label uniformly throughout host DNA, some of which showed condensed chromatin, only in infected nuclei. By contrast, BrdU associated with viral DNA was centralized and showed uniform, compartmentalized labeling. Our results demonstrate that chromosomal DNA is replicated in TGMV-infected cells. DA - 2002/12// PY - 2002/12// DO - 10.1105/tpc.005777 VL - 14 IS - 12 SP - 2995-3007 SN - 1040-4651 ER - TY - JOUR TI - Relationships within Cornales and circumscription of Cornaceae – matK and rbcL sequence data and effects of outgroups and long branches AU - Xiang, Q.Y. AU - Moody, M. AU - Soltis, D.E. AU - Fan, C.Z. AU - Soltis, P.S. T2 - Molecular Phylogeneics and Evolution AB - Phylogenetic relationships in Cornales were assessed using sequences rbcL and matK. Various combinations of outgroups were assessed for their suitability and the effects of long branches and outgroups on tree topology were examined using RASA 2.4 prior to conducting phylogenetic analyses. RASA identified several potentially problematic taxa having long branches in individual data sets that may have obscured phylogenetic signal, but when data sets were combined RASA no longer detected long branch problems. t(RASA) provides a more conservative measurement for phylogenetic signal than the PTP and skewness tests. The separate matK and rbcL sequence data sets were measured as not containing phylogenetic signal by RASA, but PTP and skewness tests suggested the reverse [corrected]. Nonetheless, the matK and rbcL sequence data sets suggested relationships within Cornales largely congruent with those suggested by the combined matK-rbcL sequence data set that contains significant phylogenetic signal as measured by t(RASA), PTP, and skewness tests. Our analyses also showed that a taxon having a long branch on the tree may not be identified as a "long-branched" taxon by RASA. The long branches identified by RASA had little effect on the arrangement of other taxa in the tree, but the placements of the long-branched taxa themselves were often problematic. Removing the long-branched taxa from analyses generally increased bootstrap support, often substantially. Use of non-optimal outgroups (as identified by RASA) decreased phylogenetic resolution in parsimony analyses and suggested different relationships in maximum likelihood analyses, although usually weakly supported clades (less than 50% support) were impacted. Our results do not recommend using t(RASA) as a sole criterion to discard data or taxa in phylogenetic analyses, but t(RASA) and the taxon variance ratio obtained from RASA may be useful as a guide for improved phylogenetic analyses. Results of parsimony and ML analyses of the sequence data using optimal outgroups suggested by RASA revealed four major clades within Cornales: (1) Curtisia-Grubbia, (2) Cornus-Alangium, (3) Nyssa-Camptotheca-Davidia-Mastixia-Diplopanax, and (4) Hydrangeaceae-Loasaceae, with clades (2) and (3) forming a monophyletic group sister to clade (4) and clade (1) sister to the remainder of Cornales. However, there was not strong bootstrap support for relationships among the major clades. The placement of Hydrostachys could not be reliably determined, although most analyses place the genus within Hydrangeaceae; ML analyses, for example, placed the genus as the sister of Hydrangeeae. Our results supported a Cornales including the systematically problematic Hydrostachys, a Cornaceae consisting of Cornus and Alangium, a Nyssaceae consisting of Nyssa and Camptotheca, a monogeneric Davidiaceae, a Mastixiaceae consisting of Mastixia and Diplopanax, and an expanded Grubbiaceae consisting of Grubbia and Curtisia, and two larger families, Hydrangeaceae and Loasaceae. DA - 2002/// PY - 2002/// DO - 10.1016/S1055-7903(02)00267-1 VL - 24 IS - 1 SP - 35–57 SN - 1095-9513 KW - Cornales KW - Cornaceae KW - Hydrostachyaceae KW - Grubbiaceae KW - molecular phylogeny KW - rbcL KW - matK KW - long-branch attraction KW - RASA ER - TY - JOUR TI - Functional expression and cellular localization of cercosporin-resistance proteins fused with the GFP in Cercospora nicotianae AU - Chung, KR AU - Ehrenshaft, M AU - Daub, ME T2 - CURRENT GENETICS DA - 2002/6// PY - 2002/6// DO - 10.1007/s00294-002-0289-8 VL - 41 IS - 3 SP - 159-167 SN - 0172-8083 KW - photosensitizer KW - singlet oxygen KW - fungi KW - pyridoxine ER - TY - JOUR TI - Ergonomic interventions for the furniture manufacturing industry. Part II - Handtools AU - Mirka, GA AU - Shivers, C AU - Smith, C AU - Taylor, J T2 - INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS AB - The objectives of this intervention research project were to develop and evaluate engineering controls for the reduction of the upper extremity injury risk in workers in the furniture manufacturing industry. The analysis of OSHA Form 200 logs and surveys of furniture workers revealed that upholsterers, workers who use random orbital sanders and workers who use spray guns are at higher levels of risk of illness than the rest of the working population. An on-site ergonomic analysis of these three jobs was performed and the following risk factors were identified for each of these three work groups: upholsterers—repetitive, high-force pinch grips; sanders—long-duration static grip forces; and sprayers—awkward postures (ulnar wrist deviations and wrist flexion). Engineering interventions in the form of new or modified handtools were then evaluated in the laboratory to assess their effectiveness in reducing exposure to these risk factors. For sanding, an interface was created that secured the hand to the sander with the intention of reducing the need for static grip forces during sanding. A new handtool was created for upholsterers that replaced the repetitive pinch grips with a power grip. Finally, a commercially available spray gun with ergonomic features was evaluated. Each of these modified tools/methods was compared with the standard methods typically used in industry. The results show that most of the intended beneficial effects were realized. The random orbital sander interface reduced extensor muscle activities by an average of 30%. The upholstery handtool reduced the intrinsic hand muscle activities by an average of 51%. The effects of the adapted spray gun were most prominent when working on horizontal surfaces and showed an average reduction of 40° of wrist flexion and 14° of ulnar deviation as compared to the standard pistol grip spray gun in this activity. The ergonomic intervention research described in this report documents a reduction in exposure to risk factors for upper extremity cumulative trauma disorders for three work activities in the furniture manufacturing industry. DA - 2002/5// PY - 2002/5// DO - 10.1016/S0169-8141(01)00068-3 VL - 29 IS - 5 SP - 275-287 SN - 0169-8141 KW - cumulative trauma disorders KW - upper extremity KW - intervention research KW - furniture industry KW - EMG ER - TY - JOUR TI - Ergonomic interventions for the furniture manufacturing industry. Part I - lift assist devices AU - Mirka, GA AU - Smith, C AU - Shivers, C AU - Taylor, J T2 - INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS AB - The objectives of this intervention research project were to develop and evaluate engineering controls for the reduction of low back injury risk in workers in the furniture manufacturing industry. An analysis of injury/illness records and survey data identified upholsterers and workers in the machine room as two occupations within the industry at elevated risk for low back injury. A detailed ergonomic evaluation of the activities performed by these workers was then performed and the high risk subtasks were identified. The analysis for upholsterers revealed: (1) high forces during the loading and unloading of the furniture to and from the upholstery bucks, (2) static awkward postures (extremeflexion>50°, lateralbending>20°, twisting>20°) during the upholstering of the furniture, and (3) repetitive bending and twisting throughout the operation. For machine room workers, this ergonomic evaluation revealed repetitive bending and twisting (up to 5 lifts/min and sagittal flexion>80°, lateral bending>15°, twisting>45°) when getting wooden components from or moving them to the shop carts that are used to transport these materials. Engineering interventions were then developed and evaluated in the laboratory to document the reduction of exposure to these stressors. The height-adjustable upholstery buck system eliminated the lifting and lowering requirements and affected trunk kinematics during the upholstery operation by reducing peak sagittal angles by up to 79% (average: 52%; range: 27–79%), peak sagittal accelerations by up to 42% (average: 71%; range: 0–74%) and peak lateral position by up to 31% (average: 20%; range: 12–31%), and showed no impact on time to complete the task. The machine room lift reduced peak sagittal angle by up to 90% (average: 76%; range: 64–90%), peak sagittal accelerations by up to 86% (average: 72%; range: 59–86%) and had a positive impact on the time to complete the task (average reduction: 19%). The ergonomic intervention research documented in this report shows the impact of engineering controls for the furniture manufacturing industry on the risk factors for work-related low back injuries. DA - 2002/5// PY - 2002/5// DO - 10.1016/S0169-8141(01)00067-1 VL - 29 IS - 5 SP - 263-273 SN - 0169-8141 KW - low back injury KW - intervention research KW - furniture industry KW - trunk motion KW - trunk posture ER - TY - JOUR TI - Differential Top10 promoter regulation by six tetracycline analogues in plant cells AU - Love, J AU - Allen, GC AU - Gatz, C AU - Thompson, WF T2 - JOURNAL OF EXPERIMENTAL BOTANY AB - The effects of five tetracycline analogues, anhydrotetracycline, doxycycline, minocycline, oxytetracycline, and tetracycline, on Top10 promoter activity in NT1 tobacco tissue culture cells have been analysed. The concentration that repressed Top10 promoter activity, the level of transgene repression and the kinetics of transgene de‐repression were determined for each analogue, and could not be predicted from in vitro binding affinity to the tetracycline repressor or from comparison with animal cells. Doxycycline had the most potent effect on the Top10 promoter and completely inhibited transgene expression at 4 nmol l–1. Tetracycline was the most versatile of the analogues tested; tetracycline inhibited the Top10 promoter at 10 nmol l–1 and was easily washed out to restore Top10‐driven expression in 12–24 h. A study was also made of the suitability for plant research of a novel tetracycline analogue, GR33076X. In animal cells, GR33076X de‐repressed Top10 promoter activity in the presence of inhibitory concentrations of anhydrotetracycline. In NT1, it is shown that GR 33076X can antagonize repression of the Top10 promoter in the presence of tetracycline, but not of anhydrotetracycline or of doxycycline. Different tetracycline analogues can therefore be used to regulate the Top10 promoter in plant cells and this property may be exploited in planning an optimum course of transgene regulation. DA - 2002/9// PY - 2002/9// DO - 10.1093/jxb/erf050 VL - 53 IS - 376 SP - 1871-1877 SN - 1460-2431 KW - tetracycline analogues KW - tobacco KW - Top10 promoter activity KW - tissue culture ER - TY - JOUR TI - A geminivirus replication protein interacts with a protein kinase and a motor protein that display different expression patterns during plant development and infection AU - Kong, LJ AU - Hanley-Bowdoin, L T2 - PLANT CELL AB - The geminivirus protein AL1 initiates viral DNA replication, regulates its own expression, and induces plant gene transcription. To better understand how AL1 interacts with host proteins during these processes, we used yeast two-hybrid library screening and a baculovirus protein interaction system to identify plant proteins that interact with AL1. These studies identified a Ser/Thr kinase, a kinesin, and histone H3 as AL1 partners. The kinase is autophosphorylated and can phosphorylate common kinase substrates in vitro. The kinesin is phosphorylated in insect cells by a cyclin-dependent kinase. Immunostaining of Nicotiana benthamiana and Arabidopsis showed that kinase protein levels and subcellular location are regulated during plant development and geminivirus infection. By contrast, the kinesin is ubiquitous even though it is associated with the spindle apparatus in mitotic cells. Together, our results establish that AL1 interacts with host proteins involved in plant cell division and development. Possible functions of these host factors in healthy and geminivirus-infected plants are discussed. DA - 2002/8// PY - 2002/8// DO - 10.1105/tpc.003681 VL - 14 IS - 8 SP - 1817-1832 SN - 1532-298X ER - TY - JOUR TI - Use of digital image analysis, viability stains, and germination assays to estimate conventional and glyphosate-resistant cotton pollen viability AU - Pline, WA AU - Edmisten, KL AU - Oliver, T AU - Wilcut, JW AU - Wells, R AU - Allen, NS T2 - CROP SCIENCE AB - Abstract Because the success of labor‐intensive hand crosses by breeders is dependent upon pollen viability, quick, simple, and inexpensive methods for viability assessment are of interest. Four such cotton pollen viability assays were compared to determine differences in viability estimates, and relative accuracy by correlation to seed set. The methods compared were Brewbaker & Kwack (B & K) medium, B & K medium plus aniline blue, a fluorochromatic reaction method (FCR), and Alexander's stain. Additionally, digital images of germinated pollen grains were analyzed by means of morphometry software to quantify pollen tube area per pollen grain, as a proposed additional method of assessing viability. Pollen from conventional, nontreated glyphosate‐resistant (GR) and glyphosate‐treated GR cotton ( Gossypium hirsutum L.) plants was tested by each method. Glyphosate treatments to GR cotton reduced pollen viability and corresponding seed set in all methods tested. Pollen germination measured by the B & K method was most closely related to seed set per boll, while Alexander's stain gave the highest estimates of viability. The FCR method indicated that many pollen grains from glyphosate‐treated GR cotton were irregularly shaped and only partially flourescein diacetate (FD) stained. All methods tested showed similar high correlation (0.7–0.8) of pollen viability to seed set. Morphometric analysis of digital images of germinated pollen found the greatest pollen tube area to pollen grain ratio with B & K medium + 30 m M sucrose. Because the B & K method most closely predicted the linear magnitude of seed set reduction to reduced pollen viability, allowed the use of morphometry software analysis, and was one of the simplest and least equipment‐demanding methods, it may provide broad utility for those assessing cotton pollen viability. DA - 2002/// PY - 2002/// DO - 10.2135/cropsci2002.2193 VL - 42 IS - 6 SP - 2193-2200 SN - 0011-183X ER - TY - JOUR TI - Effects of notebook computer configuration and task on user biomechanics, productivity, and comfort AU - Sommerich, CM AU - Starr, H AU - Smith, CA AU - Shivers, C T2 - INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS AB - This study took a comprehensive approach to evaluating effects of using a notebook computer stand-alone or along with inexpensive peripheral input devices. The study examined effects on biomechanics, productivity, and discomfort, and considered the impact of both computer configuration and task performed. It was hypothesized that, in general, the stand-alone configuration would induce greater postural fixity and more non-neutral postures than configurations with peripheral input devices. Dependent measures included muscle activity, posture and posture variation/fixity, productivity, and subjective assessments of discomfort and preference. The data were generally consistent with the hypothesis, though some biomechanical advantages were identified for each configuration; specifics and exceptions are discussed, along with reasons for a general recommendation for the use of an external mouse, or mouse and keyboard (without number pad) when using a notebook computer for an extended period of time, as in a desktop replacement scenario. Notebook computer use is rapidly increasing, in industry and schools. Yet the notebook form factor is inconsistent with a number of current design recommendations. Little research concerning physical ergonomics of notebook computer use has been conducted, so recommendations for use are currently limited and not strongly supported by objective evidence. DA - 2002/7// PY - 2002/7// DO - 10.1016/S0169-8141(02)00075-6 VL - 30 IS - 1 SP - 7-31 SN - 0169-8141 KW - portable computer KW - laptop computer KW - notebook computer KW - ergonomics KW - biomechanics KW - pointing device ER - TY - JOUR TI - When a day makes a difference. Interpreting data from endoplasmic reticulum-targeted green fluorescent protein fusions in cells grown in suspension culture AU - Persson, S. AU - Love, J. AU - Tsou, P. L. AU - Robertson, D. AU - Thompson, W. F. AU - Boss, W. F. T2 - Plant Physiology AB - The stability of the self-contained structure of green fluorescent protein (GFP) has made it the most widely utilized fluorescent marker for gene expression and subcellular localization studies ([Chalfie et al., 1994][1]; [Tsien, 1998][2]; [De Giorgi et al., 1999][3]; [Haseloff et al., 1999][4]). DA - 2002/// PY - 2002/// DO - 10.1104/pp.010840 VL - 128 IS - 2 SP - 341-344 ER - TY - JOUR TI - Effects of wheat residues on dicotyledonous weed emergence in a simulated no-till system AU - Blum, U. AU - King, L. D. AU - Brownie, C. T2 - Allelopathy Journal DA - 2002/// PY - 2002/// VL - 9 IS - 2 SP - 159-176 ER - TY - JOUR TI - Leaf initiation and development in soybean under phosphorus stress AU - Chiera, J AU - Thomas, J AU - Rufty, T T2 - JOURNAL OF EXPERIMENTAL BOTANY AB - Experiments investigated changes in leaf development in young soybean plants progressing into P stress. The apical meristem and leaf structure were examined anatomically to evaluate the involvement of cell division and cell expansion in the restriction of leaf number and individual leaf size. Seedlings were deprived of P for 32 d following germination. Leaf initiation rates declined noticeably after about 2 weeks, even though the apical dome was of similar size and had a similar number of cells as controls. Primordia appeared morphologically similar also. Expansion of primary and the first three trifoliolate leaves of -P plants was severely reduced, and expansion of each leaf ceased, uniformly, when an area of about 40 cm(2) was obtained. Leaf epidermal cell size in the lateral plane was unaffected. The results indicate that expansion of leaves under P stress was limited by the number of cell divisions, which would imply control of cell division by a common regulatory factor within the leaf canopy. DA - 2002/3// PY - 2002/3// DO - 10.1093/jexbot/53.368.473 VL - 53 IS - 368 SP - 473-481 SN - 0022-0957 KW - cell division KW - cell expansion KW - growth KW - leaf development KW - phosphorus KW - shoot apex ER - TY - JOUR TI - Geminivirus-based vectors for gene silencing in Arabidopsis AU - Turnage, MA AU - Muangsan, N AU - Peele, CG AU - Robertson, D T2 - PLANT JOURNAL AB - Gene silencing, or RNA interference, is a powerful tool for elucidating gene function in Caenorhabditis elegans and Drosophila melanogaster. The vast genetic, developmental and sequence information available for Arabidopsis thaliana makes this an attractive organism in which to develop reliable gene-silencing tools for the plant world. We have developed a system based on the bipartite geminivirus cabbage leaf curl virus (CbLCV) that allows silencing of endogenous genes singly or in combinations in Arabidopsis. Two vectors were tested: a gene-replacement vector derived from the A component; and an insertion vector derived from the B component. Extensive silencing was produced in new growth from the A component vectors, while only minimal silencing and symptoms were seen in the B component vector. Two endogenous genes were silenced simultaneously from the A component vector and silencing of the genes was maintained throughout new growth. Because the CbLCV vectors are DNA vectors they can be inoculated directly from plasmid DNA. Introduction of these vectors into intact plants bypasses transformation and extends the kinds of silencing studies that can be carried out in Arabidopsis. DA - 2002/4// PY - 2002/4// DO - 10.1046/j.1365-313X.2002.01261.x VL - 30 IS - 1 SP - 107-114 SN - 0960-7412 KW - geminivirus KW - gene silencing KW - RNAi KW - Arabidopsis KW - cabbage leaf curl virus ER - TY - JOUR TI - Sub-cellular distribution and isotypes of a 49-kDa apyrase from Pisum sativum AU - Shibata, K AU - Abe, S AU - Yoneda, M AU - Davies, E T2 - PLANT PHYSIOLOGY AND BIOCHEMISTRY AB - We isolated a 49-kDa protein from various sub-cellular fractions from pea (Pisum sativum L. var. Alaska) stems using heparin affinity and cation exchange column chromatography. The corresponding proteins from all these fractions were identified as apyrase (EC 3.6.1.5) because they hydrolyzed both nucleoside tri- and diphosphates into their respective monophosphates. Using an antibody raised against apyrase, we studied the enzyme’s sub-cellular distribution in isolated fractions and found significant amounts in the cell wall (50%), the supernatant (33%), the cytoskeleton (14%), and the nuclei (3%). Immuno-electron microscopy using gold-labeled antibody confirmed that apyrase was present in cell walls, nuclei, and in filamentous structures in the cytoplasm associated with ribosomes. Even though there is only one gene (with two alleles), for this protein, 2D gels indicated there were at least five isotypes, three being major, and the relative abundance of these isotypes differed in different fractions. Enzymes from all fractions: (a) hydrolyzed nucleoside triphosphates and diphosphates, but not monophosphates, (b) were insensitive to most ATPase inhibitors (azide, fluoride, nitrate, molybdate, ouabain, quercetin), but (c) were all inhibited by vanadium pentoxide at relatively high concentrations. There were, however, some subtle differences between enzymes from different sub-cellular fractions, including different ADP/ATP hydrolysis ratios. These results show that the 49-kDa apyrase is located in various compartments within the cell (cell wall, nuclei, and the cytoskeleton) and that the enzymes from all fractions are basically similar in their apyrase function. We suggest that the enzyme is modified in various ways to furnish different forms with different (non-apyrase) functions in different sub-cellular locations. DA - 2002/5// PY - 2002/5// DO - 10.1016/S0981-9428(02)01389-X VL - 40 IS - 5 SP - 407-415 SN - 0981-9428 KW - apyrase KW - cell wall KW - cytoskeleton KW - 2D-PAGE KW - immuno-localization KW - nucleus KW - Pisum sativum ER - TY - JOUR TI - Scaling species dynamics in Pinus palustris communities: Effects of pine straw raking AU - Kelly, LA AU - Wentworth, TR AU - Brownie, C T2 - JOURNAL OF VEGETATION SCIENCE AB - Abstract. In the southeastern USA, harvest of pine straw sometimes involves mechanical raking of natural Pinus palustris (longleaf pine) communities. Little is known about the effects of raking nor how these effects may vary in time and space. In a two yr experiment, we examined the effects of mechanized raking on Pinus palustris dominated communities (scrub oak, dry savanna, and mesic savanna) by monitoring vegetation at seven spatial scales (0.01–100 m 2 ). We measured floristic similarity and the proportion of species initially present that were gained (i.e. new species) or lost during four sampling periods. Relationships between spatial scale and these community attributes were analyzed using a repeated measures approach and functional response curves. Spatial scale clearly affected observed rates of species loss and floristic similarity; losses declined and floristic similarity increased as scale increased. We relate these patterns to expanding population sizes with scale and our inability to detect species reductions in large populations. Scale had little influence on species gains. The effects of raking did not differ across scales, but raking caused greater mean losses of species and greater mean changes in floristic similarity when mean values were calculated over all scales. Raking also increased the mean rate of species gains in the mesic savanna during one period. Otherwise, interaction effects of community and raking were largely absent from both mean values and response curves. Despite significant short‐term effects of raking, changes in species richness were minor. DA - 2002/12// PY - 2002/12// DO - 10.1111/j.1654-1103.2002.tb02105.x VL - 13 IS - 6 SP - 755-764 SN - 1100-9233 KW - disturbance KW - floristic similarity KW - longleaf pine KW - repeated measure KW - response curve KW - spatial scale KW - species gain KW - species loss ER - TY - JOUR TI - Up-regulation of phosphoinositide metabolism in tobacco cells constitutively expressing the human type I inositol polyphosphate 5-phosphatase AU - Perera, IY AU - Love, J AU - Heilmann, I AU - Thompson, WF AU - Boss, WF T2 - PLANT PHYSIOLOGY AB - To evaluate the impact of suppressing inositol 1,4,5-trisphosphate (InsP(3)) in plants, tobacco (Nicotiana tabacum) cells were transformed with the human type I inositol polyphosphate 5-phosphatase (InsP 5-ptase), an enzyme which specifically hydrolyzes InsP(3). The transgenic cell lines showed a 12- to 25-fold increase in InsP 5-ptase activity in vitro and a 60% to 80% reduction in basal InsP(3) compared with wild-type cells. Stimulation with Mas-7, a synthetic analog of the wasp venom peptide mastoparan, resulted in an approximately 2-fold increase in InsP(3) in both wild-type and transgenic cells. However, even with stimulation, InsP(3) levels in the transgenic cells did not reach wild-type basal values, suggesting that InsP(3) signaling is compromised. Analysis of whole-cell lipids indicated that phosphatidylinositol 4,5-bisphosphate (PtdInsP(2)), the lipid precursor of InsP(3), was greatly reduced in the transgenic cells. In vitro assays of enzymes involved in PtdInsP(2) metabolism showed that the activity of the PtdInsP(2)-hydrolyzing enzyme phospholipase C was not significantly altered in the transgenic cells. In contrast, the activity of the plasma membrane PtdInsP 5 kinase was increased by approximately 3-fold in the transgenic cells. In vivo labeling studies revealed a greater incorporation of (32)P into PtdInsP(2) in the transgenic cells compared with the wild type, indicating that the rate of PtdInsP(2) synthesis was increased. These studies show that the constitutive expression of the human type I InsP 5-ptase in tobacco cells leads to an up-regulation of the phosphoinositide pathway and highlight the importance of PtdInsP(2) synthesis as a regulatory step in this system. DA - 2002/8// PY - 2002/8// DO - 10.1104/pp.003426 VL - 129 IS - 4 SP - 1795-1806 SN - 1532-2548 ER - TY - JOUR TI - Biodegradation of the polyketide toxin cercosporin AU - Mitchell, TK AU - Chilton, WS AU - Daub, ME T2 - APPLIED AND ENVIRONMENTAL MICROBIOLOGY AB - ABSTRACT Cercosporin is a non-host-specific polyketide toxin produced by many species of plant pathogens belonging to the genus Cercospora . This red-pigmented, light-activated toxin is an important pathogenicity determinant for Cercospora species. In this study, we screened 244 bacterial isolates representing 12 different genera for the ability to degrade cercosporin. Cercosporin degradation was determined by screening for the presence of cleared zones surrounding colonies on cercosporin-containing culture medium and was confirmed by assaying the kinetics of degradation in liquid medium. Bacteria belonging to four different genera exhibited the cercosporin-degrading phenotype. The isolates with the greatest cercosporin-degrading activity belonged to Xanthomonas campestris pv. zinniae and X. campestris pv. pruni. Isolates of these pathovars removed over 90% of the cercosporin from culture medium within 48 h. Bacterial degradation of red cercosporin was accompanied by a shift in the color of the growth medium to brown and then green. The disappearance of cercosporin was accompanied by the appearance of a transient green product, designated xanosporic acid. Xanosporic acid and its more stable lactone derivative, xanosporolactone, are nontoxic to cercosporin-sensitive fungi and to plant tissue and are labile in the presence of light. Detailed spectroscopic analysis (to be reported in a separate publication) of xanosporolactone revealed that cercosporin loses one methoxyl group and gains one oxygen atom in the bacterial conversion. The resulting chromophore (4,9-dihydroxy-3-oxaperlylen-10H-10-one) has never been reported before but is biosynthetically plausible via oxygen insertion by a cytochrome P-450 enzyme. DA - 2002/9// PY - 2002/9// DO - 10.1128/AEM.68.9.4173-4181.2002 VL - 68 IS - 9 SP - 4173-4181 SN - 0099-2240 ER -