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Microbiology

1997

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Articles 1 - 30 of 64

Full-Text Articles in Life Sciences

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers Dec 1997

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Recombination may be an important mechanism for increasing variation in retroviral populations. Retroviral recombination has been demonstrated in tissue culture systems by artificially creating doubly infected cells. Evidence for retroviral recombination in vivo is indirect and is based principally on the identification of apparently mosaic human immunodeficiency virus type 1 genomes from phylogenetic analyses of viral sequences. We infected a rhesus monkey with two different molecularly cloned strains of simian immunodeficiency virus. One strain of virus had a deletion in vpx and vpr, and the other strain had a deletion in nef. Each strain on its own induced low virus ...


Porcine Reproductive And Respiratory Syndrome Virus Replicates In Testicular Germ Cells, Alters Spermatogenesis, And Induces Germ Cell Death By Apoptosis, Jung-Hyang Sur, Alan R. Doster, James S. Christian, Judith A. Galeota, Robert W. Wills, Jeff J. Zimmerman, Fernando A. Osorio Dec 1997

Porcine Reproductive And Respiratory Syndrome Virus Replicates In Testicular Germ Cells, Alters Spermatogenesis, And Induces Germ Cell Death By Apoptosis, Jung-Hyang Sur, Alan R. Doster, James S. Christian, Judith A. Galeota, Robert W. Wills, Jeff J. Zimmerman, Fernando A. Osorio

Virology Papers

Like other arteriviruses, porcine reproductive and respiratory syndrome virus (PRRSV) is shed in semen, a feature that is critical for the venereal transmission of this group of viruses. In spite of its epidemiological importance, little is known of the association of PRRSV or other arteriviruses with gonadal tissues. We experimentally infected a group of boars with PRRSV 12068-96, a virulent field strain. By combined use of in situ hybridization and immunohistochemistry, we detected infection by PRRSV in the testes of these boars. The PRRSV testicular replication in testis centers on two types of cells: (i) epithelial germ cells of the ...


Physiology And Ecology Of Dispersal Polymorphism In Insects, Anthony J. Zera, Robert F. Denno Nov 1997

Physiology And Ecology Of Dispersal Polymorphism In Insects, Anthony J. Zera, Robert F. Denno

Anthony Zera Publications

Studies of dispersal polymorphism in insects have played a pivotal role in advancing our understanding of population dynamics, life history evolution, and the physiological basis of adaptation. Comparative data on wing-dimorphic insects provide the most definitive evidence to date that habitat persistence selects for reduced dispersal capability. The increased fecundity of flightless females documents that a fitness tradeoff exists between flight capability and reproduction. However, only recently have studies of nutrient consumption and allocation provided unequivocal evidence that this fitness trade-off results from a trade-off of internal resources. Recent studies involving wing-dimorphic insects document that flight capability imposes reproductive penalties ...


Recovery Of Rna Polymerase Ii Synthesis Following Dna Damage In Mutants Of Saccharomyces Cerevisiae Defective In Nucleotide Excision Repair, Michael S. Reagan, Errol C. Friedberg Nov 1997

Recovery Of Rna Polymerase Ii Synthesis Following Dna Damage In Mutants Of Saccharomyces Cerevisiae Defective In Nucleotide Excision Repair, Michael S. Reagan, Errol C. Friedberg

Biology Faculty Publications

We have measured the kinetics of the recovery of mRNA synthesis in the inducible GAL10 and RNR3 genes after exposure of yeast cells to ultraviolet (UV) radiation. Such recovery is abolished in mutant strains defective in nucleotide excision repair (NER) of DNA, including a rad23 mutant. Mutants defective in the RAD7 or RAD16 genes, which are required for the repair of the non-transcribed strand but not the transcribed strand of transcriptionally active genes, show slightly faster recovery of RNA synthesis than wild-type strains. A strain deleted of the RAD26 gene, which is known to be required for strand-specific NER in ...


Flight-Muscle Polymorphism In The Cricket Gryllus Firmus: Muscle Characteristics And Their Influence On The Evolution Of Flightlessness, Anthony J. Zera, Jeffry Sall, Kimberly Grudzinski Oct 1997

Flight-Muscle Polymorphism In The Cricket Gryllus Firmus: Muscle Characteristics And Their Influence On The Evolution Of Flightlessness, Anthony J. Zera, Jeffry Sall, Kimberly Grudzinski

Anthony Zera Publications

Flight muscles of the cricket Gryllus firmus are polymorphic, existing as pink or white phenotypes. White muscles are smaller in size, have reduced number and size of muscle fibers, and have reduced in vitro enzyme activities and respiration rates relative to pink muscles of newly molted, fully winged adults. G. firmus is also polymorphic for wing length. All newly molted long-winged adults exhibited the pink-muscle phenotype, while most newly molted short-winged adults exhibited the white-muscle phenotype, which resulted from arrested muscle growth. As long-winged adults aged, fully grown pink muscle was transformed into white muscle via histolysis. The substantially higher ...


Mucinous Cystadenoma Of The Urinary Bladder, I N. Soomro, A T. Rashid Oct 1997

Mucinous Cystadenoma Of The Urinary Bladder, I N. Soomro, A T. Rashid

Department of Pathology and Laboratory Medicine

No abstract provided.


Irf-7, A New Interferon Regulatory Factor Associated With Epstein-Barr Virus Latency, Luwen Zhang, Joseph S. Pagano Oct 1997

Irf-7, A New Interferon Regulatory Factor Associated With Epstein-Barr Virus Latency, Luwen Zhang, Joseph S. Pagano

Virology Papers

The Epstein-Barr virus (EBV) BamHI Q promoter (Qp) is the only promoter used for the transcription of Epstein-Barr virus nuclear antigen 1 (EBNA-1) mRNA in cells in the most restricted (type I) latent infection state. However, Qp is inactive in type III latency. With the use of the yeast one-hybrid system, a new cellular gene has been identified that encodes proteins which bind to sequence in Qp. The deduced amino acid sequence of the gene has significant homology to the interferon regulatory factors (IRFs). This new gene and products including two splicing variants are designated IRF-7A, IRF-7B, and IRF-7C. The ...


Identification Of The Flii And Flij Components Of The Caulobacter Flagellar Type Iii Protein Secretion System, Craig Stephens, Chris Mohr, Charles Boyd, Janine Maddock, James Gober, Lucy Shapiro Sep 1997

Identification Of The Flii And Flij Components Of The Caulobacter Flagellar Type Iii Protein Secretion System, Craig Stephens, Chris Mohr, Charles Boyd, Janine Maddock, James Gober, Lucy Shapiro

Biology

Caulobacter crescentus is motile by virtue of a polar flagellum assembled during the predivisional stage of the cell cycle. Three mutant strains in which flagellar assembly was blocked at an early stage were isolated. The mutations in these strains mapped to an operon of two genes, fliI and fliJ, both of which are necessary for motility. fliI encodes a 50-kDa polypeptide whose sequence is closely related to that of the Salmonella typhimurium FliI protein, an ATPase thought to energize the export of flagellar subunits across the cytoplasmic membrane through a type III protein secretion system. fliJ encodes a 16-kDa hydrophilic ...


Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow Aug 1997

Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow

VIMS Articles

To identify the biochemical response of heterotrophic bacterioplankton to changing environmental conditions, seasonal and diel cycles of bacterial protein and DNA synthesis rates were estimated in temperate estuarine habitats from H-3-leucine (Leu) and H-3-thymidine (TdR) incorporation rates. Several short-term temperature manipulation experiments (5 to 35 degrees C) and 2 mesocosm experiments were performed to examine the effects of temperature and substrate supply on the ratio of Leu:TdR, respectively. The molar ratio of Leu to TdR varied about 5-fold (5.6 to 29.5) in the field and the values of the ratio were lower and more constant during high ...


A Nonswarming Mutant Of Proteus Mirabilis Lacks The Lrp Global Transcriptional Regulator, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes Aug 1997

A Nonswarming Mutant Of Proteus Mirabilis Lacks The Lrp Global Transcriptional Regulator, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes

Microbiology and Physiological Systems Publications and Presentations

Proteus swarming is the rapid cyclical population migration across surfaces by elongated cells that hyperexpress flagellar and virulence genes. The mini-Tn5 transposon mutant mns2 was isolated as a tight nonswarming mutant that did not elongate or upregulate flagellar and hemolysin genes. Individual cell motility was retained but was reduced. The transposon had inserted in the gene encoding the global transcriptional regulator Lrp (leucine-responsive regulatory protein), expression of which was upregulated in differentiating swarm cells. Swarming was restored to the lrp mutant by artificial overexpression of the flhDC flagellar regulatory master operon. Lrp may be a key component in generating or ...


Thermophilic Bacterial Activity In A Deep-Sea Sediment From The Pacific Ocean, Fred C. Dobbs, Karen A. Selph Aug 1997

Thermophilic Bacterial Activity In A Deep-Sea Sediment From The Pacific Ocean, Fred C. Dobbs, Karen A. Selph

OEAS Faculty Publications

Thermophilic bacterial activity was detected in a deep-sea sediment sample from the South Pacific Ocean at 12 degrees S, 135 degrees W, an area of the seafloor distant from known hydrothermal venting. Incubation of sediments amended with C-14-glutamate indicated maximal respiration (evolution of (CO2)-C-14) and assimilation (incorporation of C-14 into acid-precipitated macromolecules) of substrate at 52 degrees C, relative to 4 and 22 degrees C. A parallel experiment at another site (2 degrees S, 140 degrees W) yielded no evidence of thermophily. Thermophilic bacteria may be deposited in deep-sea sediments following their long-distance dispersal from hydrothermal vents (e.g ...


The Role Of Proximal And Distal Sequence Variations In The Presentation Of An Immunodominant Ctl Epitope Encoded By The Ecotropic Ak7 Mulv, Victor Kim, William R. Green Jul 1997

The Role Of Proximal And Distal Sequence Variations In The Presentation Of An Immunodominant Ctl Epitope Encoded By The Ecotropic Ak7 Mulv, Victor Kim, William R. Green

Open Dartmouth: Faculty Open Access Scholarship

An emv-14-derived, replication-competent ecotropic murine leukemia virus [MuLV], designated AK7, was previously cloned from the AKXL-5 recombinant inbred mouse strain and partially characterized. While genetically encoding for an envelope-derived immunodominant CTL epitope [KSPWFTTL] located in the transmembrane region of p15TM, this virus, unlike the emv-11-derived virus AKR623, fails to be efficiently recognized by AKR/Gross MuLV-specific cytotoxic T lymphocytes [CTL]. AK7 thus provides the opportunity to study the role of retroviral sequence variations that are located outside of the immunodominant epitope as a mechanism of escape from CTL-mediated immune surveillance. In an attempt to identify which region[s] of the ...


Ketodiacid Compounds That Inhibit Nematode Egg Hatching, George A. Kraus, Gregory L. Tylka Jul 1997

Ketodiacid Compounds That Inhibit Nematode Egg Hatching, George A. Kraus, Gregory L. Tylka

Iowa State University Patents

A method for inhibiting hatching of soybean cyst nematode eggs is provided comprising contacting said eggs with an effective inhibitory amount of a compound of formula (I): ##STR1## wherein R.sup.1 is H or OH, R.sup.2 is H or OH, R.sup.3 is H or (C.sub.1 -C.sub.4)alkyl, R.sup.4 is H or (C.sub.1 -C.sub.4)alkyl, R.sup.5 and R.sup.6 are individually H, (C.sub.1 -C.sub.5)alkyl, C.sub.3 -C.sub.6 (cycloalkyl)alkyl, C.sub.5 -C.sub.7 ...


Increase In Fluorescence Intensity Of 16s Rrna In Situ Hybridization In Natural Samples Treated With Chloramphenicol, Cleber C. Ouverney, Jed A. Fuhrman Jul 1997

Increase In Fluorescence Intensity Of 16s Rrna In Situ Hybridization In Natural Samples Treated With Chloramphenicol, Cleber C. Ouverney, Jed A. Fuhrman

Faculty Publications

Despite the numerous advantages of fluorescent in situ hybridization for the identification of single prokaryotic cells with 16S rRNA probes, use of the technique with natural samples, especially those from the marine environment, is still problematic. The low percentage of fluorescently labeled cells constitutes the primary problem for in situ hybridization of natural samples, probably due to low cellular rRNA content. This study represents an attempt to improve detection of marine prokaryotes by increasing cellular rRNA content without changing the species composition. Cells from three California coastal sites were treated with chloramphenicol, an inhibitor of protein synthesis and rRNA degradation ...


Phagosomal Proteins Of Dictyostelium Discoideum, Betsy L. Rezabek, Juan M. Rodriguez-Paris, James A. Cardelli, Catherine P. Chia Jul 1997

Phagosomal Proteins Of Dictyostelium Discoideum, Betsy L. Rezabek, Juan M. Rodriguez-Paris, James A. Cardelli, Catherine P. Chia

Papers in Microbiology

In recognizing food particles, Dictyostelium cell-surface molecules initiate cytoskeletal rearrangements that result in phagosome formation. After feeding D. discoideum cells latex beads, early phagosomes were isolated on sucrose step gradients. Protein analyses of these vesicles showed that they contained glycoproteins and surface-labeled species corresponding to integral plasma membrane proteins. Cytoskeletal proteins also were associated with phagosomes, including myosin II, actin and a 30 kDa-actin bundling protein. As seen by the acridine orange fluorescence of vesicles containing bacteria, phagosomes were acidified rapidly by a vacuolar H+-ATPase that was detected by immunoblotting. Except for the loss of cytoskeletal proteins, few other ...


Detection Of Dna Damage By Use Of Escherichia Coli Carrying Reca'::Lux, Uvra'::Lux, And Alka'::Lux Reporter Plasmids, Amy Cheng Vollmer, S. Belkin, D. R. Smulski, T. K. Van Dyk, R. A. Larossa Jul 1997

Detection Of Dna Damage By Use Of Escherichia Coli Carrying Reca'::Lux, Uvra'::Lux, And Alka'::Lux Reporter Plasmids, Amy Cheng Vollmer, S. Belkin, D. R. Smulski, T. K. Van Dyk, R. A. Larossa

Biology Faculty Works

Plasmids were constructed in which DNA damage-inducible promoters recA, uvrA, and alkA from Escherichia coli were fused to the Vibrio fischeri luxCDABE operon. Introduction of these plasmids into E. coli allowed the detection of a dose-dependent response to DNA-damaging agents, such as mitomycin and UV irradiation. Bioluminescence was measured in real time over extended periods. The fusion of the recA promoter to luxCDABE showed the most dramatic and sensitive responses. lexA dependence of the bioluminescent SOS response was demonstrated, confirming that this biosensor's reports were transmitted by the expected regulatory circuitry. Comparisons were made between luxCDABE and lacZ fusions ...


In Vitro Activity Of Bay 12-8039, A Novel 8-Methoxyquinolone, Compared To Activities Of Six Fluoroquinolones Against Streptococcus Pneumoniae, Haemophilus Influenzae, And Moraxella Catarrhalis, A B Brueggemann, K C Kugler, Gary V. Doern Jul 1997

In Vitro Activity Of Bay 12-8039, A Novel 8-Methoxyquinolone, Compared To Activities Of Six Fluoroquinolones Against Streptococcus Pneumoniae, Haemophilus Influenzae, And Moraxella Catarrhalis, A B Brueggemann, K C Kugler, Gary V. Doern

Open Access Articles

The in vitro activity of a novel 8-methoxyquinolone, BAY 12-8039, against recent clinical isolates of Streptococcus pneumoniae (n = 404), Haemophilus influenzae (n = 330), and Moraxella catarrhalis (n = 250) was evaluated. Activity was compared to those of six other fluoroquinolones: ciprofloxacin, clinafloxacin, levofloxacin, ofloxacin, sparfloxacin and trovafloxacin. BAY 12-8039 and clinafloxacin had the highest levels of activity against S. pneumoniae, both with a MIC at which 90% of the isolates were inhibited (MIC90) of 0.06 microg/ml. Trovafloxacin and sparfloxacin were the next most active agents versus S. pneumoniae (MIC90s = 0.12 microg/ml). No differences in activity against penicillin-susceptible ...


Ribotoxic Stress Response: Activation Of The Stress-Activated Protein Kinase Jnk1 By Inhibitors Of The Peptidyl Transferase Reaction And By Sequence-Specific Rna Damage To The Alpha-Sarcin/Ricin Loop In The 28s Rrna, Mihail S. Iordanov, David Pribnow, Jennifer L. Magun, Thanh-Hoai Dinh, Jean A. Pearson, Steven Li-Ye Chen, Bruce E. Magun Jun 1997

Ribotoxic Stress Response: Activation Of The Stress-Activated Protein Kinase Jnk1 By Inhibitors Of The Peptidyl Transferase Reaction And By Sequence-Specific Rna Damage To The Alpha-Sarcin/Ricin Loop In The 28s Rrna, Mihail S. Iordanov, David Pribnow, Jennifer L. Magun, Thanh-Hoai Dinh, Jean A. Pearson, Steven Li-Ye Chen, Bruce E. Magun

Faculty Research

Inhibition of protein synthesis per se does not potentiate the stress-activated protein kinases (SAPKs; also known as cJun NH2-terminal kinases [JNKs]). The protein synthesis inhibitor anisomycin, however, is a potent activator of SAPKs/JNKs. The mechanism of this activation is unknown. We provide evidence that in order to activate SAPK/JNK1, anisomycin requires ribosomes that are translationally active at the time of contact with the drug, suggesting a ribosomal origin of the anisomycin-induced signaling to SAPK/JNK1. In support of this notion, we have found that aminohexose pyrimidine nucleoside antibiotics, which bind to the same region in the 28S rRNA ...


Identification Of A Novel Antiapoptotic Functional Domain In Simian Virus 40 Large T Antigen., Suzanne D. Conzen, Christine A. Snay, Charles N. Cole Jun 1997

Identification Of A Novel Antiapoptotic Functional Domain In Simian Virus 40 Large T Antigen., Suzanne D. Conzen, Christine A. Snay, Charles N. Cole

Open Dartmouth: Faculty Open Access Scholarship

The ability of DNA tumor virus proteins to trigger apoptosis in mammalian cells is well established. For example, transgenic expression of a simian virus 40 (SV40) T-antigen N-terminal fragment (N-termTag) is known to induce apoptosis in choroid plexus epithelial cells. SV40 T-antigen-induced apoptosis has generally been considered to be a p53-dependent event because cell death in the brain is greatly diminished in a p53-/- background strain and is abrogated by expression of wild-type (p53-binding) SV40 T antigen. We now show that while N-termTags triggered apoptosis in rat embryo fibroblasts cultured in low serum, expression of full-length T antigens unable to ...


Four-Day Incubation Period For Blood Culture Bottles Processed With The Difco Esp Blood Culture System, Gary V. Doern, Angela B. Brueggemann, W. Michael Dunne, Stephen G. Jenkins, Diane C. Halstead, James C. Mclaughlin May 1997

Four-Day Incubation Period For Blood Culture Bottles Processed With The Difco Esp Blood Culture System, Gary V. Doern, Angela B. Brueggemann, W. Michael Dunne, Stephen G. Jenkins, Diane C. Halstead, James C. Mclaughlin

Open Access Articles

Blood culture records from 1994 to 1995 from five U.S. medical centers all using the Difco ESP continuous monitoring blood culture system were reviewed retrospectively. Among a total of 7,362 isolates of bacteria and yeasts, only 0.1% of possibly significant isolates would have been missed had blood cultures been routinely incubated for 4 days instead of the 5 days recommended by the manufacturer. Conversely, numerous contaminants, detected only on day 5, would have been eliminated by a 4-day incubation period.


Transcriptional Patterns Of The Pcd41 (U27) Locus Of Human Herpesvirus 6, Yi Zhou, Bala Chandran, Charles Wood May 1997

Transcriptional Patterns Of The Pcd41 (U27) Locus Of Human Herpesvirus 6, Yi Zhou, Bala Chandran, Charles Wood

Virology Papers

Human herpesvirus 6 (HHV-6) is a lymphotropic herpesvirus, and in vitro, it can productively infect many of the same cell types that human immunodeficiency virus (HIV) infects. Simultaneous infection of T cells by HIV and HHV-6 can lead to both activation of the HIV promoter and acceleration of the cytopathic effects. Several HHV-6 genes have been demonstrated to activate HIV promoter expression. Among them is a cDNA clone, pCD41 (U27), which codes for the HHV-6 DNA polymerase accessory protein. We have now further characterized the transcription pattern in the pCD41 locus and identified at least six RNA species, ranging in ...


Inflammatory Cytokine Expression Is Correlated With The Level Of Human Immunodeficiency Virus (Hiv) Transcripts In Hiv-Infected Placental Trophoblastic Cells., Bang Ning Lee, Nelson Ordonez, Edwina J. Popek, Jian Guo Lu, Andrew Helfgott, Nancy Eriksen, Hunter Hammill, Claudia Kozinetz, Marilyn Doyle, Mark Kline, Claire Langston, William T. Shearer, James M. Reuben Apr 1997

Inflammatory Cytokine Expression Is Correlated With The Level Of Human Immunodeficiency Virus (Hiv) Transcripts In Hiv-Infected Placental Trophoblastic Cells., Bang Ning Lee, Nelson Ordonez, Edwina J. Popek, Jian Guo Lu, Andrew Helfgott, Nancy Eriksen, Hunter Hammill, Claudia Kozinetz, Marilyn Doyle, Mark Kline, Claire Langston, William T. Shearer, James M. Reuben

Claudia A. Kozinetz

The inflammatory cytokines interleukin-1b (IL-1b), IL-6, and tumor necrosis factor alpha (TNF-a) have
been associated with increased human immunodeficiency virus(HIV) expression and enhanced lymphocyte
adhesion to trophoblastic cells in experimental systems.To determine if there is a correlation between the
expression of these cytokines and the levels of HIV transcripts in trophoblasts of term placentas from HIV-infected
women, we studied the placentae of 30 HIV-positive and 13 control gravidae. Twenty-three of the HIV-positive
women received zidovudine (ZDV) as prophylaxis against HIV vertical transmission; only one of the seven
women who did not receive ZDV was a transmitter, for an ...


Atrazine Degradation In Pesticide-Contaminated Soils: Phytoremediation Potential, Ellen L. Kruger, Jennifer C. Anhalt, Diana Sorenson, Brett Nelson, Ana L. Chouhy, Todd A. Anderson, Joel R. Coats Apr 1997

Atrazine Degradation In Pesticide-Contaminated Soils: Phytoremediation Potential, Ellen L. Kruger, Jennifer C. Anhalt, Diana Sorenson, Brett Nelson, Ana L. Chouhy, Todd A. Anderson, Joel R. Coats

Entomology Publications

Studies were conducted in the laboratory to determine the fate of atrazine in pesticide-contaminated soils from agrochemical dealer sites. No significant differences in atrazine concentrations occurred in soils treated with atrazine individually or combinations with metolachlor and trifluralin. In a screening study carried out in soils from four agrochemical dealer sites, rapid mineralization of atrazine occurred in three out of eight soils tested, with the greatest amount occurring in Bravo rhizosphere soil (35% of the applied atrazine after 9 weeks). Suppression of atrazine mineralization in the Bravo rhizosphere soil did not occur with the addition of high concentrations of herbicide ...


Reaction With Fructose Detoxifies Fumonisin B1 While Stimulating Liver-Associated Natural Killer Cell Activity In Rats, Z. Lu, W. R. Dantzer, E. C. Hopmans, V. Prisk, Joan E. Cunnick, Patricia A. Murphy, Suzanne Hendrich Mar 1997

Reaction With Fructose Detoxifies Fumonisin B1 While Stimulating Liver-Associated Natural Killer Cell Activity In Rats, Z. Lu, W. R. Dantzer, E. C. Hopmans, V. Prisk, Joan E. Cunnick, Patricia A. Murphy, Suzanne Hendrich

Food Science and Human Nutrition Publications

Fumonisin B1 (FB1) was reacted with fructose in an attempt to detoxify this mycotoxin. Fischer 344/N rats were initiated with diethylnitrosamine (15 mg/kg body weight) and then fed 69.3 μmol FB1/kg diet or 69.3 μmol FB1 reacted with fructose (FB1−fructose)/kg diet for 4 weeks. In comparison with the rats fed basal diet or FB1−fructose, the FB1-fed rats had significantly increased plasma cholesterol (P < 0.01), plasma alanine aminotransferase activity (P < 0.05), and endogenous hepatic prostaglandin production (P < 0.05). Placental glutathione S-transferase-positive and γ-glutamyl transferase-positive altered hepatic foci occurred only in the FB1-fed rats. Liver-associated natural killer (NK) cell activity was significantly decreased in the FB1-fed rats and increased in the group fed FB1-fructose, as compared with the basal group (P < 0.03). Therefore, modifying FB1 with fructose seems to prevent FB1-induced hepatotoxicity and promotion of hepatocarcinogenesis while stimulating liver-associated NK cell activity in rats.


Immune Suppression In Calves With Bovine Immunodeficiency Virus, Shucheng Zhang, Charles Wood, Wenzhi Xue, Samuel Krukenberg, Qimin Chen, Harish Minocha Mar 1997

Immune Suppression In Calves With Bovine Immunodeficiency Virus, Shucheng Zhang, Charles Wood, Wenzhi Xue, Samuel Krukenberg, Qimin Chen, Harish Minocha

Virology Papers

The present study was designed to evaluate the effect of bovine immunodeficiency virus (BIV) infection on immune functions and possible interactions between BIV and other bovine viruses in calves. Ten calves were inoculated intravenously with BIV, and five served as controls. An increased lymphocyte proliferation to BIV gag protein was demonstrated 2 to 6 weeks after BIV inoculation (P < 0.05). Lymphocyte subset differentiation revealed a decreased CD4/CD8 ratio (P < 0.05) during weeks 2 to 7, suggesting a possible immune dysfunction in BIV-infected calves. When the calves were inoculated with bovine herpesvirus type 1 (BHV-1), the antibody response to BHV-1 in BIV-infected calves was delayed and the antibody titers were significantly lower (P < 0.05). Injection of bovine viral diarrhea virus vaccine also elicited a lower neutralizing antibody response in BIV-infected calves. The results indicated that immune suppression occurred in BIV-infected calves.


Analysis Of Gene Expression During Embryonic Development In Mulberry Silkworm Bombyx Mori, Amit Singh, K. P. Gopinathan Feb 1997

Analysis Of Gene Expression During Embryonic Development In Mulberry Silkworm Bombyx Mori, Amit Singh, K. P. Gopinathan

Biology Faculty Publications

We have developed a method for dechorionation and devitellinization of the silkworm eggs without damage, to facilitate the analysis of gene expression during embryonic development of Bombyx mori. Making use of antibodies available from heterologous systems, the spatio-temporal expression patterns of peroxidase and proliferating cell nuclear antigen have been directly visualized in whole mount embryos at various stages of development without the need for generating transformed ·lines carrying specific reporter constructs. The B. mori system, previously unamenable for such studies, could thus serve as an attractive model for molecular analysis of insect development.

The attention lavished on Drosophila melanogaster as ...


Encapsidation Of Turnip Crinkle Virus Is Defined By A Specific Packaging Signal And Rna Size, Feng Qu, Thomas Jack Morris Feb 1997

Encapsidation Of Turnip Crinkle Virus Is Defined By A Specific Packaging Signal And Rna Size, Feng Qu, Thomas Jack Morris

Virology Papers

A protoplast infection assay has been used to reliably examine the viral RNA encapsidation of turnip crinkle virus (TCV). Analysis of the encapsidation of various mutant viral RNAs revealed that a 186-nucleotide (nt) region at the 3’ end of the coat protein (CP) gene, with a bulged hairpin loop of 28 nt as its most essential element, was indispensable for TCV RNA encapsidation. When RNA fragments containing the 186-nt region were used to replace the CP gene of a different virus, tomato bushy stunt virus, the resulting chimeric viral RNAs were encapsidated into TCV virions. Furthermore, analysis of the encapsidated ...


Discovery And Classification Of Ecological Diversity In The Bacterial World: The Role Of Dna Sequence Data, T. Palys, L. Nakamura, Frederick Cohan Jan 1997

Discovery And Classification Of Ecological Diversity In The Bacterial World: The Role Of Dna Sequence Data, T. Palys, L. Nakamura, Frederick Cohan

Frederick M. Cohan

No abstract provided.


Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson Jan 1997

Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson

Chemistry Faculty Publications

To define the role of the surface lipooligosaccharide (LOS) of Haemophilus ducreyi in the pathogenesis of chancroid, Tn916 mutants of H. ducreyi 35000 defective in expression of the murine monoclonal antibody (MAb) 3F11 epitope on H. ducreyi LOS were identified by immunologic screening. One mutant, designated 1381, has an LOS which lacks the MAb 3F11 epitope and migrates with an increased mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gene disrupted by the Tn916 element in strain 1381 was identified by cloning the sequences flanking the Tn916 element. The sequences were then used to probe a lambda DASHII genomic library ...


Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella Jan 1997

Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella

Chemistry Faculty Publications

Haemophilus influenzae is an important human pathogen. The lipooligosaccharide (LOS) of H. influenzae has been implicated as a virulence determinant. To better understand the assembly of LOS in nontypeable H. influenzae (NtHi), we have cloned and characterized the rfaD and rfaF genes of NtHi 2019, which encode the ADP-L-glycero-D-manno-heptose-6-epimerase and heptosyltransferase II enzymes, respectively. This cloning was accomplished by the complementation of Salmonella typhimurium lipopolysaccharide (LPS) biosynthesis gene mutants. These deep rough mutants are novobiocin susceptible until complemented with the appropriate gene. In this manner, we are able to use novobiocin resistance to select for specific NtHi LOS inner core ...