@article{suyemoto_hamrick_spears_horton_washington_havell_borst_orndorff_2013, title={Extrauterine Listeriosis in the gravid mouse influences embryonic growth and development}, volume={8}, number={8}, journal={PLoS One}, author={Suyemoto, M. M. and Hamrick, T. S. and Spears, P. A. and Horton, J. R. and Washington, I. M. and Havell, E. A. and Borst, L. B. and Orndorff, P. E.}, year={2013} } @article{temple_miyamoto_mehta_capitini_von stetina_barnes_christensen_horton_spears_orndorff_2010, title={Identification and Characterization of Two Bordetella avium Gene Products Required for Hemagglutination}, volume={78}, ISSN={["1098-5522"]}, DOI={10.1128/iai.00140-10}, abstractNote={ABSTRACTBordetella aviumcauses bordetellosis in birds, a disease similar to whooping cough caused byBordetella pertussisin children.B. aviumagglutinates guinea pig erythrocytes via an unknown mechanism. Loss of hemagglutination ability results in attenuation. We report the use of transposon mutagenesis to identify two genes required for hemagglutination. The genes (hagAandhagB) were adjacent and divergently oriented and had no orthologs in the genomes of otherBordetellaspecies. Construction of in-frame, unmarked mutations in each gene allowed examination of the role of each in conferring erythrocyte agglutination, explanted tracheal cell adherence, and turkey poult tracheal colonization. In all of thein vitroandin vivoassays, the requirement for thetrans-acting products ofhagAandhagB(HagA and HagB) was readily shown. Western blotting, using antibodies to purified HagA and HagB, revealed proteins of the predicted sizes of HagA and HagB in an outer membrane-enriched fraction. Antiserum to HagB, but not HagA, blockedB. aviumerythrocyte agglutination and explanted turkey tracheal ring binding. Bioinformatic analysis indicated the similarity of HagA and HagB to several two-component secretory apparatuses in which one product facilitates the exposition of the other. HagB has the potential to serve as a useful immunogen to protect turkeys against colonization and subsequent disease.}, number={6}, journal={INFECTION AND IMMUNITY}, author={Temple, Louise M. and Miyamoto, David M. and Mehta, Manju and Capitini, Christian M. and Von Stetina, Stephen and Barnes, H. John and Christensen, Vern L. and Horton, John R. and Spears, Patricia A. and Orndorff, Paul E.}, year={2010}, month={Jun}, pages={2370–2376} } @article{spears_suyemoto_palermo_horton_hamrick_havell_orndorff_2008, title={A Listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth}, volume={76}, ISSN={["0019-9567"]}, DOI={10.1128/IAI.00283-08}, abstractNote={ABSTRACT A Listeria monocytogenes bacteriophage was used to identify a phage-resistant Tn 917 insertion mutant of the mouse-virulent listerial strain F6214-1. The mutant was attenuated when it was inoculated orally into female A/J mice and failed to replicate efficiently in cultured mouse enterocytes. Phage binding studies indicated that the mutant had a cell surface alteration that precluded phage attachment. All phenotypes associated with the mutation could be complemented in trans by a single open reading frame (ORF) that corresponded to the ORF interrupted by the Tn 917 insertion. The complementation effected was, in all cases, at a level indistinguishable from that of the parent. The Tn 917 insertion interrupted a gene that is predicted to encode a group 2 glycosyl transferase (provisionally designated glcV ). A similar glcV gene is present in Listeria welshimeri and Listeria innocua and in some serotypes of L. monocytogenes . We speculate that the loss of the glcV product results in a defective phage receptor and that this alteration coincidentally influences a feature of the normal host-pathogen interaction required for virulence. Interestingly, the glcV lesion, while preventing phage attachment, did not alter the mutant's ability to bind to cultured mouse enterocyte monolayers. Rather, the mutation appeared to alter a subsequent step in intracellular replication measured by a reduction in plaque-forming efficiency and plaque size. In vivo, the mutant was undetectable in the liver and spleen 48 h after oral inoculation. The mutation is significant in part because it is one of the few that produce attenuation when the mutant is delivered orally. }, number={9}, journal={INFECTION AND IMMUNITY}, author={Spears, Patricia A. and Suyemoto, M. Mitsu and Palermo, Angela M. and Horton, John R. and Hamrick, Terri S. and Havell, Edward A. and Orndorff, Paul E.}, year={2008}, month={Sep}, pages={4046–4054} } @article{hanson_calkins_horton_2006, title={The effect of preharvest calcium loading on tenderness of beef longissimus, supraspinatus and semitendinosus muscle}, volume={17}, ISSN={["1046-0756"]}, DOI={10.1111/j.1745-4573.2006.00038.x}, abstractNote={ABSTRACT The objective of the study was to evaluate the effects of administration of water‐soluble calcium sources on tenderness of beef longissimus, supraspinatus and semitendinosus muscle. Cattle were treated immediately prior to harvest, with distilled water control (C), calcium chloride (CC) or calcium propionate (NutroCAL, Kemin Industries, Inc., Des Moines, IA) (CP) to provide 150 g of calcium. The meat was aged 2, 5, 7, 14 and 21 days prior to Warner–Bratzler shear force (WBS) determination. Serum calcium levels were higher (P < 0.10) in CC compared with C or CP. The longissimus muscle from CP tended to have higher muscle calcium levels (compared with C and CC steers) and numerically lower shear force values at days 2, 5, 7 and 14, compared with controls. No differences (P > 0.05) in muscle calcium or WBS values were detected among the treatments for semitendinosus and supraspinatus muscles. CP drench, prior to harvest, may decrease shear force in beef longissimus muscle.}, number={2}, journal={JOURNAL OF MUSCLE FOODS}, author={Hanson, DJ and Calkins, CR and Horton, J}, year={2006}, month={Apr}, pages={155–164} } @article{spears_engle_platter_lloyd_belk_horton_2003, title={Effects of high dietary calcium propionate and dietary cation-anion balance on calcium metabolism and longissimus muscle tenderness in finishing steers}, volume={19}, ISBN={1080-7446}, DOI={10.15232/s1080-7446(15)31461-3}, abstractNote={Abstract Forty-eight Angus and Angus-cross steers (initial BW = 657 ± 5.7 kg) were used in a 2 × 2 factorial design to determine whether feeding an anionic diet or high dietary concentrations of a soluble calcium (Ca propionate) source or both would alter Ca metabolism and subsequently longissimus tenderness. Treatments consisted of 1) control, 2) 4% Ca propionate (CaProp), 3) 2% NH 4 Cl (anionic diet), and 4) CaProp plus 2% NH 4 Cl. Experimental diets were fed for 7 d prior to slaughter. Steers were individually fed using electronic Calan gate feeders. Blood samples were obtained on d 3 and 7 at 2 h post feeding for plasma Ca determination. A striploin steak was obtained from each carcass at 48 h post harvest for muscle Ca analysis and Warner-Bratzler shear force (WBSF) determination. Addition of CaProp or NH 4 Cl to the high concentrate finishing diet reduced (P 4 Cl and CaProp, indicating that their effects were additive. Carcass characteristics were not affected by CaProp, but the anionic diet tended to reduce hot carcass weights (P=0.13) and longissimus areas (P=0.09). Plasma Ca concentrations were slightly greater in steers fed CaProp on d 3 (P}, number={6}, journal={Professional Animal Scientists}, author={Spears, J. W. and Engle, T. E. and Platter, W. R. and Lloyd, K. E. and Belk, K. E. and Horton, J.}, year={2003}, pages={424} } @article{hamrick_diaz_havell_horton_orndorff_2003, title={Influence of extracellular bactericidal agents on bacteria within macrophages}, volume={71}, ISSN={["0019-9567"]}, DOI={10.1128/IAI.71.2.1016-1019.2003}, abstractNote={ABSTRACT We employed gentamicin-sensitive and -resistant derivatives of Escherichia coli in a macrophage phagocytosis assay that compared λ bacteriophage and gentamicin as extracellular bactericidal agents. Colony counts and direct microscopic examination of phagocytized E. coli supported the conclusion that gentamicin entered macrophages, even at low concentrations, and contributed to their bactericidal activity. Also, two E. coli strains differing in the ability to express the adhesin of type 1 pili (FimH) were distinguishably different in intracellular survival when λ was used as the extracellular killing agent but were indistinguishable when gentamicin was employed. }, number={2}, journal={INFECTION AND IMMUNITY}, author={Hamrick, TS and Diaz, AH and Havell, EA and Horton, JR and Orndorff, PE}, year={2003}, month={Feb}, pages={1016–1019} } @article{hamrick_horton_spears_havell_smoak_orndorff_2003, title={Influence of pregnancy on the pathogenesis of listeriosis in mice inoculated intragastrically}, volume={71}, ISSN={["1098-5522"]}, DOI={10.1128/IAI.71.9.5202-5209.2003}, abstractNote={ABSTRACTPregnancy increases the risk of listeriosis, a systemic disease caused byListeria monocytogenes. However, there is incomplete agreement on the reasons for this increased risk. We examined two features of listeriosis in gravid and nongravid female mice following intragastric (gavage) inoculation, namely, (i) disease severity (measured by lethality) and (ii) listerial infectivity (measured by liver and spleen colonization levels up to 120 h postinoculation). Two listerial strains of differing serotype (1/2a and 4nonb) were initially employed. Neither strain produced a lethal infection in nonpregnant female mice (dose range, 106to 109CFU/mouse), and only the 4nonb strain produced lethalities in pregnant mice (dose range, 106to 108CFU/mouse). The 4nonb strain also produced a higher level of liver and spleen colonization than the 1/2a strain following gavage administration. (The two strains showed similar levels of colonization if parenterally administered.) Both strains were equally capable of binding to and forming plaques upon cultured mouse enterocytes. The ability of the 4nonb strain to produce a lethal infection in pregnant animals did not correlate with an increased incidence or level of liver and spleen colonization over that in nonpregnant females. However, the lethality rate did correlate well with the rate at which embryos and their surrounding decidual covering became infected, suggesting that intrauterine infection could be responsible for the increased disease severity in the gravid females.}, number={9}, journal={INFECTION AND IMMUNITY}, author={Hamrick, TS and Horton, JR and Spears, PA and Havell, EA and Smoak, IW and Orndorff, PE}, year={2003}, month={Sep}, pages={5202–5209} } @article{valenski_harris_spears_horton_orndorff_2003, title={The product of the fimI gene is necessary for Escherichia coli type 1 pilus biosynthesis}, volume={185}, ISSN={["0021-9193"]}, DOI={10.1128/JB.185.16.5007-5011.2003}, abstractNote={ABSTRACT Site-directed mutagenesis was employed to create lesions in fimI , a gene of uncertain function located in the chromosomal gene cluster ( fim ) involved in Escherichia coli type 1 pilus biosynthesis. Chromosomal fimI mutations produced a piliation-negative phenotype. Complementation analysis indicated that a fimI ′ -kan insertion mutation and a fimI frameshift mutation produced polarity-like effects not seen with an in-frame fimI deletion mutation. Minicell analysis associated fimI with a 16.4-kDa noncytoplasmic protein product (FimI). We conclude that FimI has a required role in normal pilus biosynthesis. }, number={16}, journal={JOURNAL OF BACTERIOLOGY}, author={Valenski, ML and Harris, SL and Spears, PA and Horton, JR and Orndorff, PE}, year={2003}, month={Aug}, pages={5007–5011} } @article{harris_spears_havell_hamrick_horton_orndorff_2001, title={Characterization of Escherichia coli type 1 pilus mutants with altered binding specificities}, volume={183}, ISSN={["0021-9193"]}, DOI={10.1128/JB.183.13.4099-4102.2001}, abstractNote={ABSTRACT PCR mutagenesis and a unique enrichment scheme were used to obtain two mutants, each with a single lesion in fimH , the chromosomal gene that encodes the adhesin protein (FimH) of Escherichia coli type 1 pili. These mutants were noteworthy in part because both were altered in the normal range of cell types bound by FimH. One mutation altered an amino acid at a site previously shown to be involved in temperature-dependent binding, and the other altered an amino acid lining the predicted FimH binding pocket. }, number={13}, journal={JOURNAL OF BACTERIOLOGY}, author={Harris, SL and Spears, PA and Havell, EA and Hamrick, TS and Horton, JR and Orndorff, PE}, year={2001}, month={Jul}, pages={4099–4102} } @article{lu_hill_hood_greeson_horton_orndorff_herndon_tonelli_2001, title={Formation of antibiotic, biodegradable polymers by processing with Irgasan DP300R (Triclosan) and its inclusion compound with beta-cyclodextrin}, volume={82}, DOI={10.1002/app.1852.abs}, abstractNote={The inclusion compound (IC) between the FDA-approved antibacterial Irgasan DP300 (Trichlosan), and β-cyclodextrin (CD) has been formed. When the Irgasan–β-CD–IC is embedded in biodegradeable/bioabsorbable films of poly(ϵ-caprolactone) (PCL) at low levels (a few wt %), they are rendered resistant to the growth of E. coli bacteria. When these same PCL films embedded with Irgasan–β-CD–IC are used as the adhesive for laminating cotton fabrics, we observe the resulting cotton laminates to also be resistant to the growth of E. coli bacteria. These results hold promise for the fabrication of bacteria-resistant polymer films and fibers, as well as antibacterial fabrics, by means of simple melt processing with Irgasan–β-CD–IC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 300–309, 2001}, number={2}, journal={Journal of Applied Polymer Science}, author={Lu, J. and Hill, M. A. and Hood, M. and Greeson, D. F. and Horton, J. R. and Orndorff, P. E. and Herndon, A. S. and Tonelli, A. E.}, year={2001}, pages={300–309} } @article{williams_dunnick_horton_greenwell_eldridge_elwell_sills_2001, title={p-nitrobenzoic acid alpha(2u) nephropathy in 13-week studies is not associated with renal carcinogenesis in 2-year feed studies}, volume={29}, DOI={10.1080/019262301317226302}, abstractNote={ The objective of this study was to characterize the renal toxicity and carcinogenicity of p-nitrobenzoi c acid in F344 rats. Dose levels in 13-week and 2-year studies ranged from 630—10,000 ppm and 1,250—5,000 ppm, respectively. At 13 weeks, renal lesions included minimal to mild hyaline droplet accumulation in male rats and karyomegaly in male and female rats. At 2 years, renal lesions included proximal tubule epithelial cell hyperplasia in male rats and oncocytic hyperplasia in high-dose male and female rats, and a decreased severity of nephropathy in males and females. The hyaline droplets in renal tubular epithelial cells of male rats at 13 weeks were morphologically similar to those described in α2u-globulin nephropathy. Using immunohistochemica l methods, α2u-globulin accumulation was associated with the hyaline droplets. In addition, at 13 weeks, cell proliferation as detected by PCNA immunohistochemistry was signifi cantly increased in males exposed to 5,000 and 10,000 ppm when compared to controls. Cytotoxicity associated with α2u-globulin nephropathy such as single-cell necrosis of the P2 segment epithelium or accumulation of granular casts in the outer medulla did not occur in the 13-week study. In addition, chronic treatment related nephrotoxic lesions attributed to accumulation of α 2u-globulin such as linear foci of mineralization within the renal papilla, hyperplasia of the renal pelvis urothelium and kidney tumors were not observed. Although there was histologic evidence of α2u-globulin accumulation in male rats at 13 weeks, the minimal severity of nephropathy suggests that the degree of cytotoxicity was below the threshold, which would contribute to the development of renal tumors at 2 years. }, number={5}, journal={Toxicologic Pathology}, author={Williams, K. D. and Dunnick, J. and Horton, J. and Greenwell, A. and Eldridge, S. R. and Elwell, M. and Sills, R. C.}, year={2001}, pages={507–513} } @article{metcalf_almond_routh_horton_dillman_orndorff_2000, title={Experimental Salmonella typhi infection in the domestic pig, Sus scrofa domestica}, volume={29}, ISSN={["0882-4010"]}, DOI={10.1006/mpat.2000.0367}, abstractNote={The domestic pig, Sus scrofa domestica, was examined as a model for typhoid fever, a severe and systemic disease of humans caused by Salmonella typhi. Six pigs were inoculated 1 week post-weaning with approximately 10(10)colony forming units (cfu) of wild type Salmonella typhi strain ISP1820 intranasally and observed for 3 weeks. S. typhi was cultured from the tonsils of 50% of the pigs at necropsy. Cultures from all other organs analysed (ileum, colon, spleen and liver) were negative. No clinical or histopathological signs of disease were observed. Pigs inoculated in parallel with swine-virulent S. choleraesuis all exhibited signs of systemic salmonellosis indicating that the parameters of the experimental infection with S. typhi (e.g. route) were appropriate. Whereas the pig has a gastrointestinal tract that is very similar to humans, our results indicated that the unique features of host and microbe interaction needed to produce typhoid fever were not mimicked in swine. Nevertheless, our observation of tonsillar involvement was consistent with former observations of S. choleraesuis and S. typhimurium infections in swine and supports a role for the tonsil in all porcine salmonella infections.}, number={2}, journal={MICROBIAL PATHOGENESIS}, author={Metcalf, ES and Almond, GW and Routh, PA and Horton, JR and Dillman, RC and Orndorff, PE}, year={2000}, month={Aug}, pages={121–126} } @article{hamrick_harris_spears_havell_horton_russell_orndorff_2000, title={Genetic characterization of Escherichia coli type 1 pilus adhesin mutants and identification of a novel binding phenotype}, volume={182}, ISSN={["0021-9193"]}, DOI={10.1128/JB.182.14.4012-4021.2000}, abstractNote={ABSTRACT Five Escherichia coli type 1 pilus mutants that had point mutations in fimH , the gene encoding the type 1 pilus adhesin FimH, were characterized. FimH is a minor component of type 1 pili that is required for the pili to bind and agglutinate guinea pig erythrocytes in a mannose-inhibitable manner. Point mutations were located by DNA sequencing and deletion mapping. All mutations mapped within the signal sequence or in the first 28% of the predicted mature protein. All mutations were missense mutations except for one, a frameshift lesion that was predicted to cause the loss of approximately 60% of the mature FimH protein. Bacterial agglutination tests with polyclonal antiserum raised to a LacZ-FimH fusion protein failed to confirm that parental amounts of FimH cross-reacting material were expressed in four of the five mutants. The remaining mutant, a temperature-sensitive (ts) fimH mutant that agglutinated guinea pig erythrocytes after growth at 31°C but not at 42°C, reacted with antiserum at both temperatures in a manner similar to the parent. Consequently, this mutant was chosen for further study. Temperature shift experiments revealed that new FimH biosynthesis was required for the phenotypic change. Guinea pig erythrocyte and mouse macrophage binding experiments using the ts mutant grown at the restrictive and permissive temperatures revealed that whereas erythrocyte binding was reduced to a level comparable to that of a fimH insertion mutant at the restrictive temperature, mouse peritoneal macrophages were bound with parental efficiency at both the permissive and restrictive temperatures. Also, macrophage binding by the ts mutant was insensitive to mannose inhibition after growth at 42°C but sensitive after growth at 31°C. The ts mutant thus binds macrophages with one receptor specificity at 31°C and another at 42°C. }, number={14}, journal={JOURNAL OF BACTERIOLOGY}, author={Hamrick, TS and Harris, SL and Spears, PA and Havell, EA and Horton, JR and Russell, PW and Orndorff, PE}, year={2000}, month={Jul}, pages={4012–4021} } @article{hamrick_havell_horton_orndorff_2000, title={Host and bacterial factors involved in the innate ability of mouse macrophages to eliminate internalized unopsonized Escherichia coli}, volume={68}, ISSN={["0019-9567"]}, DOI={10.1128/IAI.68.1.125-132.2000}, abstractNote={ABSTRACTIn an effort to better understand genetic and cellular factors that influence innate immunity, we examined host and bacterial factors involved in the nonopsonic phagocytosis and killing ofEscherichia coliK-12 by mouse macrophages. Unelicited (resident) peritoneal macrophages from five different mouse strains, BALB/c, C57BL/6, CD-1, C3H/HeJ, and C3H/HeN, were employed. Additional macrophage populations were obtained from CD-1 mice (bone marrow-derived macrophages). Also, for BALB/c and C57BL/6 mice, peritoneal macrophages elicited with either thioglycolate or proteose peptone, bone marrow-derived macrophages, and macrophage-like cell lines derived from the two strains were employed. TwoE. coliK-12 strains that differed specifically in their abilities to produce type 1 pili containing the adhesive protein FimH were examined. The parameters used to assess macrophage bacteriocidal activity were (i) the killing of internalized (gentamicin-protected)E. coliduring the approximately 4-h assay and (ii) the initial rate at which internalizedE. coliwere eliminated. Data on these parameters allowed the following conclusions: (i) unelicited or proteose peptone-elicited peritoneal macrophages were significantly better at eliminating internalized bacteria than thioglycolate-elicited peritoneal macrophages, bone marrow-derived macrophages, or macrophage cell lines; (ii) the host genetic background had no significant effect upon the ability of unelicited peritoneal macrophages to killE. coli(even though the mouse strains differ widely in their in vivo susceptibilities to bacterial infection); and (iii) the FimH phenotype had no significant effect uponE. colisurvival once the bacterium was inside a macrophage. Additionally, there was no correlation between the bacteriocidal effectiveness of a macrophage population and the number of bacteria bound per macrophage. However, macrophage populations that were the least bacteriocidal tended to bind higher ratios of FimH+to FimH−E. coli. The effect of gamma interferon, fetal calf serum, and the recombination proficiency ofE. coliwere examined as factors predicted to influence intracellular bacterial killing. These had no effect upon the rate ofE. colielimination by unelicited peritoneal macrophages.}, number={1}, journal={INFECTION AND IMMUNITY}, author={Hamrick, TS and Havell, EA and Horton, JR and Orndorff, PE}, year={2000}, month={Jan}, pages={125–132} } @article{huang_taylor_gerber_orndorff_horton_tonelli_1999, title={Formation of antibiotic, biodegradable/bioabsorbable polymers by processing with neomycin sulfate and its inclusion compound with beta-cyclodextrin}, volume={74}, ISSN={["0021-8995"]}, DOI={10.1002/(SICI)1097-4628(19991024)74:4<937::AID-APP20>3.0.CO;2-K}, abstractNote={Samples of pure neomycin sulfate and its inclusion compound (IC) with β-cyclodextrin were implanted into films of poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL). Both polymers have been widely used commercially to make sutures. The antibacterial activity of these films against Escherichia coli was tested. Films made by either solution casting or melt pressing were divided into the following three groups: (1) plain polymer films, (2) those embedded with pure neomycin sulfate, and (3) those embedded with neomycin sulfate-β-cyclodextrin IC. Filter paper treated with 1.5 μL of 10 mg/μL Kanamycin and neomycin were used as controls and resulted in 11- and 8-mm zones of inhibition/or antibacterial activity, respectively. Small discs (ca. 2% of total area) cut from solution-cast films of PLLA and PCL containing 50 wt % neomycin sulfate IC had 17- and 16-mm zones of inhibition, and PLLA and PCL containing 50 wt % pure neomycin sulfate deterred bacterial growth, resulting in 19-mm zones of inhibition. Melt-pressed films containing 10 wt % pure neomycin sulfate or its IC, showed 17- and 11-mm zones of inhibition for PLLA films, respectively, while PCL films showed 13- and 9-mm zones of inhibition, respectively. For melt-pressed films that contain 0.01 wt % pure neomycin sulfate or its IC, PLLA films showed 11- and 9.5-mm zones of inhibition, respectively, while PCL films showed 11- and 10-mm zones of inhibition, respectively. Since an antibiotic, bioabsorbable suture does not require surgical removal, implanting an inclusion compound in the suture might allow the slow release of antibiotic, thereby guarding against postsurgical infection and also protecting the antibiotic from degradation during the melt-spinning process used to make the suture. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 937–947, 1999}, number={4}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Huang, L and Taylor, H and Gerber, M and Orndorff, PE and Horton, JR and Tonelli, A}, year={1999}, month={Oct}, pages={937–947} }