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Articles 751 - 780 of 875

Full-Text Articles in Microbiology

Human Herpesvirus Type 8 Dna Sequences In Cell-Free Plasma And Mononuclear Cells Of Kaposi's Sarcoma Patients, William J. Harrington, Omar Bagasra, Carlos E. Sosa, Lisa E. Bobroski, Marianna Baum, Xue Lan Wen, Lisa Cabral, Gerald E. Byrne, Roger J. Pomerantz, Charles Wood Nov 1996

Human Herpesvirus Type 8 Dna Sequences In Cell-Free Plasma And Mononuclear Cells Of Kaposi's Sarcoma Patients, William J. Harrington, Omar Bagasra, Carlos E. Sosa, Lisa E. Bobroski, Marianna Baum, Xue Lan Wen, Lisa Cabral, Gerald E. Byrne, Roger J. Pomerantz, Charles Wood

Nebraska Center for Virology: Faculty Publications

Human herpesvirus (HHV) type 8 bas been detected in both classical and AIDS-related Kaposi's sarcoma, body-cavity lymphomas, and other types of tumors. HHV-8 has also been detected in DNA from peripheral blood mononuclear cells (PBMC) of some Kaposi's sarcoma patients and more readily in B cell fractions derived from panned cell subpopulations. Two patients were followed using several methods: in situ hybridization, solution-based polymerase chain reaction (PCR), and in situ PCR. HHV-8 was intermittently detected in plasma and detection correlated with detection in PBMC. In situ PCR demonstrated HHV-8 sequences in both peripheral blood B lymphocytes and, to a lesser …

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Bacillus Thuringiensis Hd-73 Spores Have Surface-Localized Cry1ac Toxin: Physiological And Pathogenic Consequences, Cheng Du, Kenneth Nickerson Oct 1996

Bacillus Thuringiensis Hd-73 Spores Have Surface-Localized Cry1ac Toxin: Physiological And Pathogenic Consequences, Cheng Du, Kenneth Nickerson

Papers in Microbiology

Spores from Cry+ strains of Bacillus thuringiensis bound fluorescein isothiocyanate-labeled antibodies specific for the 65-kDa activated Cry 1Ac toxin, whereas spores from Bacillus cereus and Cry- strains of B. thuringiensis did not. The Cry+ spores could be activated for germination by alkaline conditions (pH 10.3), whereas Cry- spores could not. Once the surrounding exosporia had been removed or permeabilized, Cry+ spores were able to bind the toxin receptor(s) from insect gut brush border membrane vesicle preparations, and their germination rates were increased ca. threefold in the presence of brush border membrane vesicles. A model is …

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Crystal Protein Expression During Vegetative Growth Of Dictyostelium, Kristy K. Taylor, Catherine P. Chia Sep 1996

Crystal Protein Expression During Vegetative Growth Of Dictyostelium, Kristy K. Taylor, Catherine P. Chia

Papers in Microbiology

We are studying interactions between membrane proteins and the cytoskeleton of Dictyostelium discoideum. Detergent (Triton X-100) -insoluble cytoskeletons from vegetative (AX2) amebae are enriched in a 70 kDa Concanavalin A (Con A)-binding protein (gp70). An enriched fraction of gp70 was prepared by Con A affinity chromatography of cytoskeletons from axenically-grown cells. N-terminal amino acid sequence of gel-purified gp70 established its identity to a 69 kDa 'crystal protein' previously characterized by Bomblies, et al. (1990, J. Cell Biol. 110:669 -679). Enzymatic deglycosylation of gp70 resulted in a 65 kDa product that did not bind Con A, verifying the predicted number …

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In Vivo Detection Of Porcine Reproductive And Respiratory Syndrome Virus Rna By In Situ Hybridization At Different Times Post-Infection, Jung-Hyang Sur, Vicki Cooper, Judith A. Galeota, Richard A. Hesse, Alan R. Doster, Fernando A. Osorio Sep 1996

In Vivo Detection Of Porcine Reproductive And Respiratory Syndrome Virus Rna By In Situ Hybridization At Different Times Post-Infection, Jung-Hyang Sur, Vicki Cooper, Judith A. Galeota, Richard A. Hesse, Alan R. Doster, Fernando A. Osorio

Nebraska Center for Virology: Faculty Publications

We studied the distribution of porcine reproductive and respiratory syndrome virus (PRRSV) RNA in tissues by in situ hybridization at different times postinfection (p.i.). The probe used for in situ hybridization was prepared by reverse transcription of PRRSV RNA, followed by PCR amplification of the cDNA. The sequence amplified corresponded to 433 bp from PRRSV open reading frame 7, which is contained in the nucleocapsid protein gene and which is highly conserved in both European and American strains (H. Mardassi, L. Wilson, S. Mounir, and S. Dea, J. Clin. Microbiol. 32:2197–2203, 1994). An immunohistochemical technique was used to detect PRRSV …

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Vif-Negative Human Immunodeficiency Virus Type 1 Persistently Replicates In Primary Macrophages, Producing Attenuated Progeny Virus, Iqbal Chowdhury, Wei Chao, Mary Jane Potash, Pavel Sova, Howard Gendelman, David J. Volsky Aug 1996

Vif-Negative Human Immunodeficiency Virus Type 1 Persistently Replicates In Primary Macrophages, Producing Attenuated Progeny Virus, Iqbal Chowdhury, Wei Chao, Mary Jane Potash, Pavel Sova, Howard Gendelman, David J. Volsky

Nebraska Center for Virology: Faculty Publications

The vif gene of human immunodeficiency virus type 1 (HIV-1) is required for efficient infection of primary T lymphocytes. In this study, we investigated in detail the role of vif in productive infection of primary monocyte-derived macrophages (MDM). Viruses carrying missense or deletion mutations in vif were constructed on the background of the monocytotropic recombinant NLHXADA-GP. Using MDM from multiple donors, we found that vif mutants produced in complementing or partially complementing cell lines were approximately 10% as infectious as wild-type virus when assayed for incomplete, complete, and circularized viral DNA molecules by quantitative PCR amplification or for viral core …

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The Bacillus Thuringiensis Insecticidal Toxin Binds Biotin-Containing Proteins, Cheng Du, Kenneth Nickerson Aug 1996

The Bacillus Thuringiensis Insecticidal Toxin Binds Biotin-Containing Proteins, Cheng Du, Kenneth Nickerson

Papers in Microbiology

Brush border membrane vesicles from larvae of the tobacco hornworm, Manduca sexta, contain protein bands of 85 and 120 kDa which react directly with streptavidin conjugated to alkaline phosphatase. The binding could be prevented either by including 10 μM biotin in the reaction mixture or by prior incubation of the brush border membrane vesicles with an activated 60- to 65-kDa toxin from Bacillus thuringiensis HD-73. The ability of B. thuringiensis toxins to recognize biotin-containing proteins was confirmed by their binding to pyruvate carboxylase, a biotin-containing enzyme, as well as to biotinylated ovalbumin and biotinylated bovine serum albumin but not …

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Molecular Studies On Biv Infection And Its Interaction With Other Bovine Viruses, Charles Wood, Harish Minocha, Yunqi Geng Jun 1996

Molecular Studies On Biv Infection And Its Interaction With Other Bovine Viruses, Charles Wood, Harish Minocha, Yunqi Geng

Nebraska Center for Virology: Faculty Publications

Bovine immunodeficiency virus (BIV) is a bovine lentivirus that infects animals world-wide. The authors have cloned the BIV env and gag proteins and several sub-unit peptides spanning the entire coding regions of the two proteins as fusions to the bacterial trpE protein and expressed them in Escherichia coli (Spindler et al. 1984). These recombinant proteins can readily be expressed but the expression levels of these peptides varied. When these proteins were tested against a panel of bovine sera, only sera from BIV-infected animals reacted specifically. One major antigenic determinant was identified in the cartoxyl terminus of the p26 gag protein …

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Longitudinal Studies Of Viral Sequence, Viral Phenotype, And Immunologic Parameters Of Human Immunodeficiency Virus Type 1 Infection In Perinatally Infected Twins With Discordant Disease Courses, Cecelia Hutto, Yi Zhou, Jun He, Rebeca Geffin, Martin Hill, Walter Scott, Charles Wood Jun 1996

Longitudinal Studies Of Viral Sequence, Viral Phenotype, And Immunologic Parameters Of Human Immunodeficiency Virus Type 1 Infection In Perinatally Infected Twins With Discordant Disease Courses, Cecelia Hutto, Yi Zhou, Jun He, Rebeca Geffin, Martin Hill, Walter Scott, Charles Wood

Nebraska Center for Virology: Faculty Publications

Perinatal human immunodeficiency virus type 1 (HIV-1) infections cause a broad spectrum of clinical disease and are variable in both the age of the patient at onset of serious disease and the progression of the clinical course. Heterozygotic perinatally infected twins with a marked difference in their clinical courses were monitored during the first 2 years of life. Twin B, the second-born twin, developed AIDS by 6 months of age and died at 22 months of age, while twin A remained minimally symptomatic through the first 2 years. Sequential blood specimens were obtained from the twins in order to characterize …

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Tyrosine Kinase-Dependent Release Of An Adenovirus Preterminal Protein Complex From The Nuclear Matrix, Peter C. Angeletti, Jeffrey A. Engler May 1996

Tyrosine Kinase-Dependent Release Of An Adenovirus Preterminal Protein Complex From The Nuclear Matrix, Peter C. Angeletti, Jeffrey A. Engler

Nebraska Center for Virology: Faculty Publications

Adenovirus (Ad) replicative complexes form at discrete sites on the nuclear matrix (NM) through the interaction of Ad preterminal protein (pTP). The NM is a highly salt-resistant fibrillar network which is known to anchor transcription, mRNA splicing, and DNA replication complexes. Incubation of rATP with NM to which pTP was bound caused the release of pTP as a pTP-NM complex with a size of 220 to 230 kDa; incubation with 5’ adenylylimidodiphosphate (rAMP-PNP) showed no significant release, indicating that rATP hydrolysis was required. With NM extracts, it was shown that a pTP-NM complex which was capable of binding Ad origin …

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Infection Of Primary Human Fetal Astrocytes By Human Herpesvirus 6, Jun He, Micheline Mccarthy, Yi Zhou, Bala Chandran, Charles Wood Feb 1996

Infection Of Primary Human Fetal Astrocytes By Human Herpesvirus 6, Jun He, Micheline Mccarthy, Yi Zhou, Bala Chandran, Charles Wood

Nebraska Center for Virology: Faculty Publications

Human herpesvirus 6 (HHV-6) is a lymphotropic betaherpesvirus which productively infects human CD4+ T cells and monocytes. HHV-6 is the etiologic agent for exanthem subitum (roseola), and it is well-known that central nervous system complications occur frequently during the course of HHV-6-associated disease. In addition, HHV-6 has been associated with encephalitis or encephalopathy. However, very little is known about its tropism for neural cells. There are reports that HHV-6 may infect some glial cell lines, but whether it can infect any primary neural cells is not known. Our studies show that both HHV-6A (GS) and HHV-6B (Z-29) can infect …

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Artificial Selection On Jhe Activity In Gryllus Assimilis: Nature Of Activity Differences Between Lines And Effect On Jh Binding And Metabolism, Anthony J. Zera, Jeffrey Sall, Robert Schwartz Feb 1996

Artificial Selection On Jhe Activity In Gryllus Assimilis: Nature Of Activity Differences Between Lines And Effect On Jh Binding And Metabolism, Anthony J. Zera, Jeffrey Sall, Robert Schwartz

Anthony Zera Publications

Genetic lines of the cricket Gryllus assimilis selected for elevated vs. decreased activity of hemolymph juvenile hormone esterase (JHE) exhibited a 6.8-fold difference in enzyme activity by the seventh generation of selection. This documents that hemolymph JHE activity has the capability for rapid evolutionary change. This is the only insect endocrine trait for which such data are currently available. The difference in hemolymph JHE activity between the lines was due, to an equivalent degree, to variation in whole-cricket enzyme activity and allocation of JHE activity to the hemolymph compartment. No differences in kinetic or thermostability characteristics were observed between JHEs …

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Herpesvirus-Like Dna In Aids Kaposi’S Sarcoma In Argentina [Letter To The Editor], Carlos E. Sosa, Jorge A. Benetucci, Laura M. Sieczkowski, Anibal Vazquez, Xue-Lan Wen, Marianna Baum, Winslow Klaskala, William J. Harrington Jr., Charles Wood Jan 1996

Herpesvirus-Like Dna In Aids Kaposi’S Sarcoma In Argentina [Letter To The Editor], Carlos E. Sosa, Jorge A. Benetucci, Laura M. Sieczkowski, Anibal Vazquez, Xue-Lan Wen, Marianna Baum, Winslow Klaskala, William J. Harrington Jr., Charles Wood

Nebraska Center for Virology: Faculty Publications

First paragraph: Recently, Chang et al., using a new molecular biology technique termed Representational Difference Analysis, found herpesvirus-like DNA (KSHV) in AIDS patients with Kaposi’s sarcoma (KS). The presence of KSHV DNA sequences suggests that a new human herpesvirus may be associated with KS. The 5′ end of the 1853-bp flanking region of KSHV (nucleotides 1 to 607) was found to have 66 and 67% homologies to the corresponding regions of the major capsid protein gene of Herpesvirus Saimiri (ORF25) and Epstein Barr virus (BcLF1), respectively, both members of the gammaherpesvirus family. This finding is an important breakthrough, because a …

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Membrane Topology Of The Colicin A Pore-Forming Domain Analyzed By Disulfide Bond Engineering, Denis Duche, Jacques Izard, Juan M. Gonzalez-Manas, Michael W. Parker, Marcel Crest, Daniel Baty Jan 1996

Membrane Topology Of The Colicin A Pore-Forming Domain Analyzed By Disulfide Bond Engineering, Denis Duche, Jacques Izard, Juan M. Gonzalez-Manas, Michael W. Parker, Marcel Crest, Daniel Baty

Department of Food Science and Technology: Faculty Publications

Four colicin A double-cysteine mutants possessing a disulfide bond in their pore-forming domain were constructed to study the translocation and the pore formation of colicin A. The disulfide bonds connected a-helices 1 and 2, 2 and 10, 3 and 9, or 3 and 10 of the poreforming domain. The disulfide bonds did not prevent the colicin A translocation through the Escherichia coli envelope. However, the mutated colicins were able to exert their in vivo channel activity only after reduction of their disulfide bonds. In vitro studies with brominated phospholipid vesicles and planar lipid bilayers revealed that the disulfide bond that …

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Evolutionary Endocrinology Of Juvenile Hormone Esterase In Gryllus Assimilis: Direct And Correlated Responses To Selection, Anthony J. Zera, Caiqiu Zhang Nov 1995

Evolutionary Endocrinology Of Juvenile Hormone Esterase In Gryllus Assimilis: Direct And Correlated Responses To Selection, Anthony J. Zera, Caiqiu Zhang

Anthony Zera Publications

Hemolymph juvenile hormone esterase (JHE) activity on the third day of the last stadium in the cricket, Gryllus assimilis, exhibited a significant response to selection in each of six replicate lines. Mean realized heritability was 0.26 ± 0.04. The response was due to changes in whole-organism enzyme activity as well as to changes in the proportion of enzyme allocated to the hemolymph compartment. In vivo juvenile hormone metabolism differed between some lines selected for high vs. low enzyme activity. Only minimal differences were observed between lines with respect to hemolymph protein concentration or whole-cricket activity of juvenile hormone epoxide …

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Association Between Ns3 And Ns5 Proteins Of Dengue Virus Type 2 In The, Mini Kapoor, Luwen Zhang, Muralidhara Ramachandra, Jingo Kusukawa, Kurt E. Ebner, R. Padmanabhan Aug 1995

Association Between Ns3 And Ns5 Proteins Of Dengue Virus Type 2 In The, Mini Kapoor, Luwen Zhang, Muralidhara Ramachandra, Jingo Kusukawa, Kurt E. Ebner, R. Padmanabhan

Nebraska Center for Virology: Faculty Publications

Dengue virus type 2, a member of the family Flaviviridae, encodes a single polyprotein precursor consisting of 3391 amino acid residues that is processed to at least 10 mature proteins by host and viral proteases. The NS3 protein contains a domain commonly found in cellular serine proteinases that in cooperation with NS2B is involved in polyprotein processing. In addition, NS3 and NS5 proteins contain conserved motifs found in several RNA helicases and RNA-dependent RNA polymerases, respectively. Both enzymatic activities have been suggested to be involved in viral RNA replication. In this report, we demonstrate that the NS3 and NS5 proteins …

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Tumor Necrosis Factor Alpha-Induced Apoptosis In Human Neuronal Cells: Protection By The Antioxidant N-Acetylcysteine And The Genes Bcl-2 And Crma, Angela K. Talley, Stephen Dewhurst, Seth W. Perry, Sheila C. Dollard, Suryaram Gummuluru, Steven M. Fine, Deborah New, Leon Epstein, Howard Gendelman, Harris A. Gelbard May 1995

Tumor Necrosis Factor Alpha-Induced Apoptosis In Human Neuronal Cells: Protection By The Antioxidant N-Acetylcysteine And The Genes Bcl-2 And Crma, Angela K. Talley, Stephen Dewhurst, Seth W. Perry, Sheila C. Dollard, Suryaram Gummuluru, Steven M. Fine, Deborah New, Leon Epstein, Howard Gendelman, Harris A. Gelbard

Nebraska Center for Virology: Faculty Publications

Tumor necrosis factor alpha (TNF-α) is a candidate human immunodeficiency virus type 1-induced neurotoxin that contributes to the pathogenesis of AIDS dementia complex. We report here on the effects of exogenous TNF-α on SK-N-MC human neuroblastoma cells differentiated to a neuronal phenotype with retinoic acid. TNF-α caused a dose-dependent loss of viability and a corresponding increase in apoptosis in differentiated SK-N-MC cells but not in undifferentiated cultures. Importantly, intracellular signalling via TNF receptors, as measured by activation of the transcription factor NF-kB, was unaltered by retinoic acid treatment. Finally, overexpression of bcl-2 or crmA conferred resistance to apoptosis mediated by …

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Media Components Influence Viral Gene Expression Assays In Human Fetal Astrocyte Cultures, Micheline Mccarthy, Charles Wood, Larisa Fedoseyeva, Scott R. Whittemore Jan 1995

Media Components Influence Viral Gene Expression Assays In Human Fetal Astrocyte Cultures, Micheline Mccarthy, Charles Wood, Larisa Fedoseyeva, Scott R. Whittemore

Nebraska Center for Virology: Faculty Publications

In vitro neurovirological studies of viral infectivity or viral gene expression may be confounded by the mulHple neural cell types and/or fibrob last contamination present in early passage cultures prepared from dissociated human central nervous system (eNS) tissue. We have developed highly enriched astrocyte cultures for neurovirological study by culturing in a serum-free defined medium, 816, supplemented with basic fibroblast growth factor (FGF-2). Subculture in this medium selects against fibroblast proliferation and favors sustained proliferation of a highly enriched glial fibrillary acidic protein (GFAP)-positive cell population. These astrocytes support productive replication of cytomegalovirus (CMV) and transient expression of transfected CMVand …

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Correlation Between Precolonization Of Trigeminal Ganglia By Attenuated Strains Of Pseudorabies Virus And Resistance To Wild-Type Virus Latency, L. M. Schang, G. F. Kutish, Fernando A. Osorio Dec 1994

Correlation Between Precolonization Of Trigeminal Ganglia By Attenuated Strains Of Pseudorabies Virus And Resistance To Wild-Type Virus Latency, L. M. Schang, G. F. Kutish, Fernando A. Osorio

Nebraska Center for Virology: Faculty Publications

We compared the levels of latent pseudorabies virus (PRV) DNA in trigeminal ganglia (TG) of pigs after intranasal inoculation of different PRV strains by using quantitative DNA PCR. The extent of colonization attained in each case varied significantly according to the type of strain and inoculum dose, wild-type (WT) PRV being the most efficient strain in colonizing TG. When groups of pigs representing different levels of precolonization of TG with an attenuated PRV strain were challenged with WT PRV, it became evident that there is a statistically significant inverse correlation between the extent of precolonization attained by an attenuated PRV …

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Alpha Interferon-Induced Antiretroviral Activities: Restriction Of Viral Nucleic Acid Synthesis And Progeny Virion Production In Human Immunodeficiency Virus Type 1-Infected Monocytes, Lisa Baca-Regen, Nina Heinzinger, Mario Stevenson, Howard Gendelman Nov 1994

Alpha Interferon-Induced Antiretroviral Activities: Restriction Of Viral Nucleic Acid Synthesis And Progeny Virion Production In Human Immunodeficiency Virus Type 1-Infected Monocytes, Lisa Baca-Regen, Nina Heinzinger, Mario Stevenson, Howard Gendelman

Nebraska Center for Virology: Faculty Publications

Alpha interferon (IFN-a) restricts multiple steps of the human immunodeficiency virus type 1 (HIV-i) life cycle. A well-described effect of IFN-a is in the modulation of viral nucleic acid synthesis. We demonstrate that IFN-α influences HIV-1 DNA synthesis principally by reducing the production of late products of reverse transcription. The magnitude of IFN-α-induced downregulation of HIV-1 DNA and/or progeny virion production was dependent on the IFN-α concentration, the duration of cytokine administration, the multiplicity of infection, the viral strain, and the cycles of viral infection. Interestingly, reductions in viral DNAs could not fully account for the observed IFN-a-induced abrogation of …

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Comparison Of Disulfide Contents And Solubility At Alkaline Ph Of Insecticidal And Noninsecticidal Bacillus Thuringiensis Protein Crystals, Cheng Du, Phyllis A.W. Martin, Kenneth W. Nickerson Oct 1994

Comparison Of Disulfide Contents And Solubility At Alkaline Ph Of Insecticidal And Noninsecticidal Bacillus Thuringiensis Protein Crystals, Cheng Du, Phyllis A.W. Martin, Kenneth W. Nickerson

Papers in Microbiology

We compared two insecticidal and eight noninsecticidal soil isolates of Bacillus thuringiensis with regard to the solubility of their proteinaceous crystals at alkaline pH values. The protein disulfide contents of the insecticidal and noninsecticidal crystals were equivalent. However, six of the noninsecticidal crystals were soluble only at pH values of ≥12. This lack of solubility contributed to their lack of toxicity. One crystal type which was soluble only at pH ≥12 (strain SHP 1-12) did exhibit significant toxicity to tobacco hornworm larvae when the crystals were presolubilized. In contrast, freshly prepared crystals from the highly insecticidal strain HD-1 were solubilized …

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Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, Thomas Jack Morris Sep 1994

Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, Thomas Jack Morris

Nebraska Center for Virology: Faculty Publications

We have analyzed atypical tomato bushy stunt virus defective interfering (DI) RNA species which accumulated during a passage series in protoplasts. We present a rationale for the order of appearance of these molecules and show, using competition assays, that either segment duplication or single nucleotide insertion can enhance DI RNA competitiveness. Possible mechanisms for the introduction of the modifications observed in these DI RNAs are discussed.

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Purification And Characterization Of Two Forms Of A High-Molecular-Weight Cysteine Proteinase (Porphypain) From Porphyromonas Gingivalis, Pawel Ciborowski, Makoto Nishikata, Roger D. Allen, Marilyn S. Lantz Aug 1994

Purification And Characterization Of Two Forms Of A High-Molecular-Weight Cysteine Proteinase (Porphypain) From Porphyromonas Gingivalis, Pawel Ciborowski, Makoto Nishikata, Roger D. Allen, Marilyn S. Lantz

Nebraska Center for Virology: Faculty Publications

Porphyromonas gingivalis, an organism implicated in the etiology and pathogenesis of human periodontal diseases, produces a variety of potent proteolytic enzymes, and it has been suggested that these enzymes play a direct role in the destruction of periodontal tissues. We now report that two cell-associated cysteine proteinases of P. gingivalis W12, with molecular masses of approximately 150 kDa (porphypain-1) and 120 kDa (porphypain-2), as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, have been separated and purified to apparent homogeneity. These proteinases appear to be SDS-stable conformational variants of a 180-kDa enzyme, and they are the largest cysteine proteinases …

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Molecular Analysis Of The Rfb Gene Cluster Of A Group D2 Salmonella Enterica Strain: Evidence For Its Origin From An Insertion Sequence-Mediated Recombination Event Between Group E And Dl Strains, Shi-Hua Xiang, Matthew Hobbs, Peter R. Reeves Jul 1994

Molecular Analysis Of The Rfb Gene Cluster Of A Group D2 Salmonella Enterica Strain: Evidence For Its Origin From An Insertion Sequence-Mediated Recombination Event Between Group E And Dl Strains, Shi-Hua Xiang, Matthew Hobbs, Peter R. Reeves

Nebraska Center for Virology: Faculty Publications

The Salmonella enterica O antigen is a highly variable surface polysaccharide composed of a repeated oligosaccharide (the O unit). The O unit produced by serogroup D2 has structural features in common with those of groups Dl and El, and hybridization studies had previously suggested that the D2 rfb gene cluster responsible for O-unit biosynthesis is indeed a hybrid of the two. In this study, the rfb gene cluster was cloned from a group D2 strain of S. enterica sv. Strasbourg. Mapping, hybridization, and DNA sequencing showed that the organization of the D2 rfb genes is similar to that of group …

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Differential Resource Consumption Obviates A Potential Flight–Fecundity Trade-Off In The Sand Cricket (Gryllus Firmus), S. Mole, Anthony J. Zera Jun 1994

Differential Resource Consumption Obviates A Potential Flight–Fecundity Trade-Off In The Sand Cricket (Gryllus Firmus), S. Mole, Anthony J. Zera

Anthony Zera Publications

1. The physiological basis of life-history trade-offs is poorly understood. A useful system in which the underlying physiological mechanisms can be studied is wing polymorphism in insects.
2. The sand cricket, Gryllus firmus (Orthoptera, Gryllidae), exists in natural populations as either a fully-winged (LW), flight-capable morph or as a short-winged (SW) morph that cannot fly.
3. We characterized the morphs with respect to physiological features that influence a potential trade-off between flight capability and fecundity. We measured nutritional indices, flight muscle development and ovarian development in the LW and SW morphs.
4. In adults, ovarian growth occurred after the completion …

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Nonhomologous Rna Recombination In Tombusviruses: Generation And Evolution Of Defective Interfering Rnas By Stepwise Deletions, K. Andrew White, Thomas Jack Morris Jan 1994

Nonhomologous Rna Recombination In Tombusviruses: Generation And Evolution Of Defective Interfering Rnas By Stepwise Deletions, K. Andrew White, Thomas Jack Morris

Nebraska Center for Virology: Faculty Publications

We used a protoplast system to study the mechanisms involved in the generation and evolution of defective interfering (DI) RNAs of tomato bushy stunt tombusvirus (TBSV). Synthetic transcripts corresponding to different naturally occurring TBSV DI RNAs, or to various artificially constructed TBSV defective RNAs, were analyzed. The relative levels of competitiveness of different DI RNAs were determined by coinoculating their corresponding transcripts into protoplasts along with helper genomic RNA transcripts and monitoring the level of DI RNA accumulation. Further studies were performed to assess the contribution of naked DI RNA stability and DI RNA encapsidation efficiency to the observed levels …

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Infection Of Macrophages With Lymphotropic Human Immunodeficiency Virus Type 1 Can Be Arrested After Viral Dna Synthesis, Zheng-Bo Huang, Mary Jane Potash, Malgorzata Simm, Wei Chao, Howard Gendelman, Edward Edin, David J. Volsky Nov 1993

Infection Of Macrophages With Lymphotropic Human Immunodeficiency Virus Type 1 Can Be Arrested After Viral Dna Synthesis, Zheng-Bo Huang, Mary Jane Potash, Malgorzata Simm, Wei Chao, Howard Gendelman, Edward Edin, David J. Volsky

Nebraska Center for Virology: Faculty Publications

Lymphotropic strains of human immunodeficiency virus type 1 (HIV-1), including HTLV-IIIB, replicate poorly in macrophages. We have shown previously that lymphotropic HIV-1 fuses equally well with T lymphocytes and macrophages (M. J. Potash, M. Zeira, Z.-B. Huang, T. Pearce, E. Eden, H. Gendelman, and D. J. Volsky, Virology 188:864-868, 1992), suggesting that events in the virus life cycle following virus-cell fusion limit virus replication. We report here that HIV-1 DNA is synthesized effliciently in either ADA or HTLV-IIIB infected alveolar macrophages or monocyte-derived macrophages within 24 h of virus infection, as observed by polymerase chain reaction for amplification of viral …

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Isolation And Characterization Of New Wild-Type Isolates Of Bovine Lentivirus, David Suarez, Martin Van Der Maaten, Charles Wood, Ceclia Whetstone Aug 1993

Isolation And Characterization Of New Wild-Type Isolates Of Bovine Lentivirus, David Suarez, Martin Van Der Maaten, Charles Wood, Ceclia Whetstone

Nebraska Center for Virology: Faculty Publications

Two new isolates of bovine lentivirus, also known as bovine immunodeficiency-like virus (BIV), were obtained from a seropositive cattle herd in Florida. This is the first report of new isolates of BIV since the original BIV strain, R29, was isolated in 1%9. The two new BIV isolates were derived from blood butFy coat cells cocultivated in vitro with fetal bovine lung cell cultures. The new isolates differed in vitro from the original R29 isolate in replication and syncytium formation in fetal bovine lung cells. Both new isolates were confirmed as BIV by immunofluorescence assay, Western blotting (immunoblotting), and polymerase chain …

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Nonenzymatic Glycosylation Of Lepidopteran-Active Bacillus Thuringiensis Protein Crystals, Meenakshi Bhattacharyi, Bradley A. Plantz, Jane D. Swanson-Kobler, Kenneth W. Nickerson Aug 1993

Nonenzymatic Glycosylation Of Lepidopteran-Active Bacillus Thuringiensis Protein Crystals, Meenakshi Bhattacharyi, Bradley A. Plantz, Jane D. Swanson-Kobler, Kenneth W. Nickerson

Papers in Microbiology

We used high-pH anion-exchange chromatography with pulsed amperometric detection to quantify the monosaccharides covalently attached to Bacillus thuringiensis HD-1 (Dipel) crystals. The crystals contained 0.54% sugars, including, in decreasing order of prevalence, glucose, fucose, arabinose/rhamnose, galactose, galactosamine, glucosamine, xylose, and mannose. Three lines of evidence indicated that these sugars arose from nonenzymatic glycosylation: (i) the sugars could not be removed by N- or O-glycanases; (ii) the sugars attached were influenced both by the medium in which the bacteria had been grown and by the time at which the crystals were harvested; and (iii) the chemical identity and stoichiometry of the …

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Identifying Bovine Respiratory Syncytial Virus By Reverse Transcription-Polymerase Chain Reaction And Oligonucleotide Hybridizations, R. D. Oberst, M. P. Hays, K. J. Hennessey, L. C. Stine, J. F. Evermann, Clayton L. Kelling May 1993

Identifying Bovine Respiratory Syncytial Virus By Reverse Transcription-Polymerase Chain Reaction And Oligonucleotide Hybridizations, R. D. Oberst, M. P. Hays, K. J. Hennessey, L. C. Stine, J. F. Evermann, Clayton L. Kelling

Nebraska Center for Virology: Faculty Publications

An assay to identify tissue culture cells infected with bovine respiratory syncytial virus (BRSV) that utilizes reverse transcription (RT), the polymerase chain reaction (PCR), and a synthetic oligonucleotide hybridization probe has been developed. The RT-PCR assay uses a BRSV-specific negative-sense oligonucleotide primer to synthesize cDNA from a BRSV fusion protein mRNA template and another BRSV-specific oligonucleotide primer (positive sense) upstream from the negative-sense primer for PCR amplification. In the presence of mRNA templates of BRSV isolates originating from locations throughout the United States, the BRSV RT-PCR assay resulted in amplified products (381 bp) that were specific to BRSV, as demonstrated …

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Differential Mating Success Of Male Wing Morphs Of The Cricket, Gryllus Rubens, Cami L. Holtmeier, Anthony J. Zera Apr 1993

Differential Mating Success Of Male Wing Morphs Of The Cricket, Gryllus Rubens, Cami L. Holtmeier, Anthony J. Zera

Anthony Zera Publications

Genetically marked individuals were used to study differential mating success between male wing morphs of the cricket, Gryllus rubens. Previous studies of Gryllus rubens and other wing-dimorphic insects have documented that flightless short-winged or wingless females typically attain reproductive maturity earlier and oviposit more eggs relative to their long-winged counterparts. This study was done to determine if flightless males also exhibit enhanced reproductive characteristics. Segregation analyses documented the genetic basis of allozymes used to infer paternity in subsequent experiments. Control experiments documented the absence of effects on mating success independent of wing morph due to (1) the genetic stock …

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