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Articles 781 - 810 of 875

Full-Text Articles in Microbiology

Differential Allocation Of Resources Underlies The Dispersal-Reproduction Trade-Off In The Wing-Dimorphic Cricket, Gryllus Rubens, Simon Mole, Anthony J. Zera Feb 1993

Differential Allocation Of Resources Underlies The Dispersal-Reproduction Trade-Off In The Wing-Dimorphic Cricket, Gryllus Rubens, Simon Mole, Anthony J. Zera

Anthony Zera Publications

The cricket, Gryllus rubens (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. The SW morph is substantially more fecund than the LW morph. In this study we report on the physiological basis of this trade-off between flight capability and fecundity. Results from gravimetric feeding trials indicate that LW and SW morphs are equivalent in their consumption and digestion of food. However, during the adult stage, the LW morph is less efficient in converting assimilated nutrients into biomass. This may be a consequence of the respired loss …

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Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan Jan 1993

Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan

Nebraska Center for Virology: Faculty Publications

The power of molecular biology is unleashed with the ability to clone and sequence genes, and then express these genes in heterologous systems. This sets the stage for the full analysis of proteins that are otherwise difficult to isolate and/or purify, especially when present at very low copy number per cell or when isolated from relatively precious materials. Overexpression of protein is now possible in a number of systems including prokaryotes (e.g., E. coli) and various eukaryotes (yeast, insects, and plants). The issue then becomes, which system (1) most closely reflects the homologous expression with respect to posttranslational modifications, …

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Loss Of Infectivity By Progeny Virus From Alpha Interferon- Treated Human Immunodeficiency Virus Type 1-Infected T Cells Is Associated With Defective Assembly Of Envelope Gp120, Brian D. Hanson, Peter L. Nara, Radha K. Maheshwari, Girmel S. Sidhu, John G. Bernbaum, David Hoekzema, Monte S. Meltzer, Howard Gendelman Dec 1992

Loss Of Infectivity By Progeny Virus From Alpha Interferon- Treated Human Immunodeficiency Virus Type 1-Infected T Cells Is Associated With Defective Assembly Of Envelope Gp120, Brian D. Hanson, Peter L. Nara, Radha K. Maheshwari, Girmel S. Sidhu, John G. Bernbaum, David Hoekzema, Monte S. Meltzer, Howard Gendelman

Nebraska Center for Virology: Faculty Publications

Levels of human immunodeficiency virus (HIV) DNA, RNA, or p24 antigen and reverse transcriptase activity in T-cell cultures treated with 500 IU of recombinant alpha interferon (rIFNα) per ml were comparable to those in control cultures. Radioimmunoprecipitation analysis of proteins in lysates of IFN-treated T cells documented a marked accumulation of HlV proteins. Localization of gp120 by immunofluorescence showed a diffuse pattern in IFN-treated cells quite distinct from the ring pattern in untreated control cells. That large quantities of a120 in aberrant cell compartments might affect HlV morphogenesis was confirmed in infectivity studies: virions from IFN-treated cells were 100- to …

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Processing And Localization Of Dengue Virus Type 2 Polyprotein Precursor Ns3-Ns4a-Ns4b-Ns5, Luwen Zhang, P. Maruthi Mohan, R. Padmanabhan Dec 1992

Processing And Localization Of Dengue Virus Type 2 Polyprotein Precursor Ns3-Ns4a-Ns4b-Ns5, Luwen Zhang, P. Maruthi Mohan, R. Padmanabhan

Nebraska Center for Virology: Faculty Publications

Processing of dengue virus type 2 polyprotein precursor NS3-NS4A-NS4B-NS5 could be mediated by the catalytically active NS3 protease domain and NS2B in trans at the dibasic sites NS3-NS4A and NS4B-NS5. Subcellular localization of the unprocessed precursor NS3-NS4A-NS4B-NS5 showed that it was confined to a distinct subcellular organelle in the cytoplasm, which was distinct from the distribution of the mature NS5.

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The Entner-Doudoroff Pathway In Escherichia Coli Is Induced For Oxidative Glucose Metabolism Via Pyrroloquinoline Quinone-Dependent Glucose Dehydrogenase, Ronda Fliege, Suxiang Tong, Annemarie Shibata, Kenneth W. Nickerson, Tyrrell Conway Dec 1992

The Entner-Doudoroff Pathway In Escherichia Coli Is Induced For Oxidative Glucose Metabolism Via Pyrroloquinoline Quinone-Dependent Glucose Dehydrogenase, Ronda Fliege, Suxiang Tong, Annemarie Shibata, Kenneth W. Nickerson, Tyrrell Conway

Papers in Microbiology

The Entner-Doudoroff pathway was shown to be induced for oxidative glucose metabolism when Escherichia coli was provided with the periplasmic glucose dehydrogenase cofactor pyrroloquinoline quinone (PQQ). Induction of the Entner-Doudoroff pathway by glucose plus PQQ was established both genetically and biochemically and was shown to occur in glucose transport mutants, as well as in wild-type E. coli. These data complete the body of evidence that proves the existence of a pathway for oxidative glucose metabolism in E. coli. PQQ-dependent oxidative glucose metabolism provides a metabolic branch point in the periplasm; the choices are either oxidation to gluconate followed …

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Identification And Characterization Of The Bovine Immunodeficiency-Like Virus Tat Gene, Zhen-Qian Liu, Deborah Sheridan, Charles Wood Aug 1992

Identification And Characterization Of The Bovine Immunodeficiency-Like Virus Tat Gene, Zhen-Qian Liu, Deborah Sheridan, Charles Wood

Nebraska Center for Virology: Faculty Publications

A cDNA clone of the bovine immunodeficiency-like virus (BW) trans-activator gene (tat) was identified and characterized. The tat cDNA clone was generated by splicing, and on the basis of sequence analysis, the Tat protein was found to be encoded entirely by the first exon. It is 103 amino acids in size and shares sequence homology with the human immunodeficiency virus (HW) Tat. The BIV tat clone can trans activate the BIV promoter effectively, as measured by the expression of the bacterial chloramphenicol acetyltransferase gene, when transfected into bovine cells. Besides activating the BIV promoter, the BIV Tat can also trans …

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Lipoxygenase Inhibitors Shift The Yeast/Mycelium Dimorphism In Ceratocystis Ulmi, Ellen C. Jensen, Clyde Ogg, Kenneth W. Nickerson Aug 1992

Lipoxygenase Inhibitors Shift The Yeast/Mycelium Dimorphism In Ceratocystis Ulmi, Ellen C. Jensen, Clyde Ogg, Kenneth W. Nickerson

Papers in Microbiology

The yeast-mycelium dimorphism in Ceratocystis ulmi, the causative agent of Dutch elm disease, was switched by gossypol, nordihydroguaiaretic acid, and propylgallate. In each case the mycelial form was converted to the yeast form. These compounds are recognized lipoxygenase inhibitors. Inhibitors of cyclooxygenase and thromboxane synthetase did not cause mycelia to shift to the yeast form. We suggest the following two-part hypothesis: (i) that lipoxygenase is a target for antifungal antibiotics and (ii) that many phytoalexins (antimicrobial compounds of plant origin) are targeted toward fungal lipoxygenases. In addition, in a study to determine potential lipoxygenase substrates, a fatty acid analysis …

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Dual Regulation Of Silent And Productive Infection In Monocytes By Distinct Human Immunodeficiency Virus Type 1 Determinants, Howard Gendelman, Peter Westervelt, Timothy Henkel, David B. Trowbridge, Jan Orenstein, John Heuser, Lee Ratner Jun 1992

Dual Regulation Of Silent And Productive Infection In Monocytes By Distinct Human Immunodeficiency Virus Type 1 Determinants, Howard Gendelman, Peter Westervelt, Timothy Henkel, David B. Trowbridge, Jan Orenstein, John Heuser, Lee Ratner

Nebraska Center for Virology: Faculty Publications

The regulation of human immunodeficiency virus type 1 infection and replication in primary monocytes was investigated by mutagenesis of recombinant proviral clones containing an env determinant required for the infectivity of monocytes. Virus replication was assayed by determination of reverse transcriptase activity in culture fluids and by recovery of virus from monocytes following cocultivation with uninfected peripheral blood mononuclear cells. Three virus replication phenotypes were observed in monocytes: productive infection, silent infection, and no infection. Incorporation of the monocytetropic env determinant in a full-length clone incapable of infection or replication in primary monocytes (no infection) conferred the capacity for highly …

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Identification And Characterization Of A Human Herpesvirus 6 Gene Segment That Trans Activates The Human Immunodeficiency Virus Type 1 Promoter, Yunqi Geng, Bala Chandran, Steven Josephs, Charles Wood Mar 1992

Identification And Characterization Of A Human Herpesvirus 6 Gene Segment That Trans Activates The Human Immunodeficiency Virus Type 1 Promoter, Yunqi Geng, Bala Chandran, Steven Josephs, Charles Wood

Nebraska Center for Virology: Faculty Publications

Human herpesvirus 6 (HHV-6) is a lymphotropic herpesvirus, and in vitro, HHV-6 can productively infect many of the same cell types as can human immunodeficiency virus (HIV). Coinfection by both viruses in vitro can lead to both activation of the HIV promoter and acceleration of cytopathic effects. We have previously demonstrated that a large, 22.25-kb cloned HHV-6 fragment, pZVB70, can trans activate HIV promoter expression in vitro. In this study, we show that the pZVB70 fragment can trans activate the HIV promoter in human T-cell lines as well as in the monkey kidney cell line CV-1. The pZVB70 insert was …

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Altered Expression Of Adenovirus 12 Dna-Binding Protein But Not Dna Polymerase During Abortive Infection Of Hamster Cells, Lynne A. Lucher, Benjawan Khuntirat, Jiansheng Zhao, Peter C. Angeletti Jan 1992

Altered Expression Of Adenovirus 12 Dna-Binding Protein But Not Dna Polymerase During Abortive Infection Of Hamster Cells, Lynne A. Lucher, Benjawan Khuntirat, Jiansheng Zhao, Peter C. Angeletti

Nebraska Center for Virology: Faculty Publications

Replication of human adenovirus type 12 DNA is blocked in abortively infected baby hamster kidney cells. The activity and accumulation of adenovirus 12 DNA polymerase is equivalent in infected hamster and human cell extracts. However, the accumulation of adenovirus type 12 DNA-binding protein is approximately 120-fold lower in extracts from infected hamster cells when compared to infected permissive human cells. This difference in accumulation is not because of replication of viral DNA during productive infection, since this difference is observed in the presence of hydroxyurea. The DNA-binding protein from infected hamster cells retains the ability to bind denatured DNA-cellulose. An …

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The Inability Of Human Immunodeficiency Virus To Infect Chimpanzee Monocytes Can Be Overcome By Serial Viral Passage In Vivo, Howard Gendelman, Garth D. Ehrlich, Lisa M. Baca, Shawn Conley, Jorge Ribas, D. Chester Kalter, Monte S. Meltzer, Bernard J. Poiesz, Peter Nara Jul 1991

The Inability Of Human Immunodeficiency Virus To Infect Chimpanzee Monocytes Can Be Overcome By Serial Viral Passage In Vivo, Howard Gendelman, Garth D. Ehrlich, Lisa M. Baca, Shawn Conley, Jorge Ribas, D. Chester Kalter, Monte S. Meltzer, Bernard J. Poiesz, Peter Nara

Nebraska Center for Virology: Faculty Publications

Studies of lentivirus infection in ruminants, nonhuman primates, and humans suggest that virus infection of macrophages plays a central role in the disease process. To investigate whether human immunodeficiency virus type 1 (HIV-1) can infect chimpanzee macrophages, we recovered monocytes from peripheral blood mononuclear cells of HIV-1-negative animals and inoculated these and control human monocytes with a panel of four human-passaged monocytotropic virus strains and one chimpanzee-passaged isolate. HIV-1-infected human monocytes synthesized proviral DNA, viral mRNA, p24 antigen, and progeny virions. In contrast, except for the chimpanzee-passaged HIV-1 isolate, chimpanzee monocytes failed to support HIV-1 replication when cultured under both …

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Nutritional Complementation Of Oxidative Glucose Metabolism In Escherichia Coli Via Pyrroloquinoline Quinone-Dependent Glucose Dehydrogenase And The Entner-Doudoroff Pathway, Michael Adamowicz, Tyrrell Conway, Kenneth W. Nickerson Jul 1991

Nutritional Complementation Of Oxidative Glucose Metabolism In Escherichia Coli Via Pyrroloquinoline Quinone-Dependent Glucose Dehydrogenase And The Entner-Doudoroff Pathway, Michael Adamowicz, Tyrrell Conway, Kenneth W. Nickerson

Papers in Microbiology

Two glucose-negative Escherichia coli mutants (ZSC113 and DF214) were unable to grow on glucose as the sole carbon source unless supplemented with pyrroloquinoline quinone (PQQ). PQQ is the cofactor for the periplasmic enzyme glucose dehydrogenase, which converts glucose to gluconate. Aerobically, E. coli ZSC113 grew on glucose plus PQQ with a generation time of 65 min, a generation time about the same as that for wildtype E. coli in a defined glucose-salts medium. Thus, for E. coli ZSC113 the Entner-Doudoroff pathway was fully able to replace the Embden-Meyerhof-Parnas pathway. In the presence of 5% sodium dodecyl sulfate, PQQ no longer …

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Transactivation Of The Human Immunodeficiency Virus Promoter By Human Herpesvirus 6 (Hhv-6) Strains Gs And 2-29 In Primary Human T Lymphocytes And Identification Of Transactivating Hhv-6(Gs) Gene Fragments, Rebecca Horvat, Charles Wood, Steven Josephs, N. Balachandran Jun 1991

Transactivation Of The Human Immunodeficiency Virus Promoter By Human Herpesvirus 6 (Hhv-6) Strains Gs And 2-29 In Primary Human T Lymphocytes And Identification Of Transactivating Hhv-6(Gs) Gene Fragments, Rebecca Horvat, Charles Wood, Steven Josephs, N. Balachandran

Nebraska Center for Virology: Faculty Publications

Human herpesvirus 6 (HHV-6) can activate the human immunodeficiency virus (HIV) promoter and accelerate cytopathic effects in HIV-infected human T cells. This study examines the regions of the HIV promoter required for HHVd transactivation in a heterogeneous population of primary human T lymphocytes with or without antigenic stimulation. Two different strains of HHV-6, GS and 229, transactivated the HIV promoter. The GS strain transactivated the promoter in both stimulated and resting T cells, while the 229 strain increased HIV promoter activity only in stimulated T cells. Three DNA clones containing HHV-6(GS) genomic fragments transactivated the HIV promoter in cotransfected T …

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Transactivation Of The Human Immunodeficiency Virus Promoter By Human Herpesvirus 6 (Hhv-6) Strains Gs And Z-29 In Primary Human T Lymphocytes And Identification Of Transactivating Hhv-6(Gs) Gene Fragments, Rebecca Horvat, Charles Wood, Steven Josephs, N. Balanchandran Jun 1991

Transactivation Of The Human Immunodeficiency Virus Promoter By Human Herpesvirus 6 (Hhv-6) Strains Gs And Z-29 In Primary Human T Lymphocytes And Identification Of Transactivating Hhv-6(Gs) Gene Fragments, Rebecca Horvat, Charles Wood, Steven Josephs, N. Balanchandran

Nebraska Center for Virology: Faculty Publications

Human herpesvirus 6 (HHV-6) can activate the human immunodeficiency virus (HIV) promoter and accelerate cytopathic effects in HIV-infected human T cells. This study examines the regions of the HIV promoter required for HHV-6 transactivation in a heterogeneous population of primary human T lymphocytes with or without antigenic stimulation. Two different strains of HHV-6, GS and Z29, transactivated the HIV promoter. The GS strain transactivated the promoter in both stimulated and resting T cells, while the Z29 strain increased HIV promoter activity only in stimulated T cells. Three DNA clones containing HHV-6(GS) genomic fragments transactivated the HIV promoter in cotransfected T …

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Rapid Detection Of Bovine Viral Diarrhea Virus By Polymerase Chain Reaction, O. J. Lopez, Fernando A. Osorio, Ruben O. Donis Mar 1991

Rapid Detection Of Bovine Viral Diarrhea Virus By Polymerase Chain Reaction, O. J. Lopez, Fernando A. Osorio, Ruben O. Donis

Nebraska Center for Virology: Faculty Publications

The polymerase chain reaction was used to detect genomic sequences of the positive-stranded RNA of bovine viral diarrhea virus (BVDV), a member of the family Togaviridae. Using a set of 20-bp primers located within the conserved 3' region of the BVDV genome, we were able to consistently amplify a 205-bp target sequence from BVDV cDNA. BVDV RNAs from cell culture-propagated BVDV reference strains, diverse unrelated cytopathic and noncytopathic field isolates, and clinical serum samples were transcribed to cDNA by using avian myeloblastosis virus reverse transcriptase and further specifically amplified by using the polymerase chain reaction assay. The amplification assay …

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Detergent (Sodium Dodecyl Sulfate) Shock Proteins In Escherichia Coli, Michael Adamowicz, Philip M. Kelley, Kenneth W. Nickerson Jan 1991

Detergent (Sodium Dodecyl Sulfate) Shock Proteins In Escherichia Coli, Michael Adamowicz, Philip M. Kelley, Kenneth W. Nickerson

Papers in Microbiology

The protein composition of Escherichia coli W3110 grown in the presence and absence of 5% sodium dodecyl sulfate (SDS) was examined by two-dimensional gel electrophoresis. In SDS-grown cells, at least 4 proteins were turned on, 13 were turned off, 15 were elevated, and 15 were depressed. The 19 unique and elevated SDS-induced spots constituted 7.91% of the total 35S-labeled protein. There was no apparent overlap between these 19 detergent (SDS) stress proteins and those of other known bacterial stress responses. The detergent stress stimulon is a distinct and independent stimulon. Its physiological relevance probably derives from the presence of …

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The Viral Envelope Gene Is Involved In Macrophage Tropism Of A Human Immunodeficiency Virus Type 1 Strain Isolated From Brain Tissue, Zhen-Qian Liu, Charles Wood, Jay Levy, Cecilia Cheng-Mayer Dec 1990

The Viral Envelope Gene Is Involved In Macrophage Tropism Of A Human Immunodeficiency Virus Type 1 Strain Isolated From Brain Tissue, Zhen-Qian Liu, Charles Wood, Jay Levy, Cecilia Cheng-Mayer

Nebraska Center for Virology: Faculty Publications

Human immunodeficiency virus type 1 (HIV-1) strains isolated from the central nervous system (CNS) may represent a subgroup that displays a host cell tropism different from those isolated from peripheral blood and lymph nodes. One CNS-derived isolate, HIV-lSF128A , which can be propagated efficiently in primary macrophage culture but not in any T-cell lines, was molecularly cloned and characterized. Recombinant viruses between HIV-1SF128A and the peripheral blood isolate HIV-ISF2 were generated in order to map the viral gene(s) responsible for the macrophage tropism. The env gene sequences of the two isolates are about 91.1% homologous, with variations …

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The Viral Envelope Gene Is Involved In Macrophage Tropism Of A Human Immunodeficiency Virus Type 1 Strain Isolated From Brain Tissue, Zhen-Qian Lou, Charles Wood, Jay Levy, Cecilia Cheng-Mayer Dec 1990

The Viral Envelope Gene Is Involved In Macrophage Tropism Of A Human Immunodeficiency Virus Type 1 Strain Isolated From Brain Tissue, Zhen-Qian Lou, Charles Wood, Jay Levy, Cecilia Cheng-Mayer

Nebraska Center for Virology: Faculty Publications

Human immunodeficiency virus type 1 (HIV-1) strains isolated from the central nervous system (CNS) may represent a subgroup that displays a host cell tropism different from those isolated from peripheral blood and lymph nodes. One CNS-derived isolate, HIV-lSFl28A, which can be propagated efficiently in primary macrophage culture but not in any T-cell lines, was molecularly cloned and characterized. Recombinant viruses between HIV-lSF128A and the peripheral blood isolate HIV-lSF2 were generated in order to map the viral gene(s) responsible for the macrophage tropism. The env gene sequences of the two isolates are about 91.1% homologous, with variations …

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Toxicity Of Protease-Resistant Domains From The Delta-Endotoxin Of Bacillus Thuringiensis Subsp. Israelensis In Culex Quinquefasciatus And Aedes Aegypti Bioassays, Mary Ann Pfannenstiel, William C. Cray Jr., Graham Couche, Kenneth W. Nickerson Jan 1990

Toxicity Of Protease-Resistant Domains From The Delta-Endotoxin Of Bacillus Thuringiensis Subsp. Israelensis In Culex Quinquefasciatus And Aedes Aegypti Bioassays, Mary Ann Pfannenstiel, William C. Cray Jr., Graham Couche, Kenneth W. Nickerson

Papers in Microbiology

The mosquitocidal glycoprotein endotoxin of Bacillus thuringiensis subsp. israelensis was digested with chymotrypsin to yield protease-resistant domains which were then separated from smaller protease digestion products by high-performance liquid chromatography. Once purified, the domains no longer bound wheat germ agglutinin, a lectin which binds N-acetylglucosamine (GlcNAc) and GlcNAc oligomers. Purified protease-resistant domains were as toxic for Culex quinquefasciatus larvae as intact solubilized toxin. In separate experiments, the toxicity of chymotrypsin-digested endotoxin for Aedes aegypti larvae was reduced fivefold or more. A model is presented in which GlcNAc-containing oligosaccharides are required for toxicity for A. aegypti larvae but not C. …

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Use Of Trpe/Gag Fusion Proteins To Characterize Immunoreactive Domains On The Human Immunodeficiency Virus Type 1 Core Protein, Michael Windheuser, Gary Tegtmeier, Charles Wood Sep 1989

Use Of Trpe/Gag Fusion Proteins To Characterize Immunoreactive Domains On The Human Immunodeficiency Virus Type 1 Core Protein, Michael Windheuser, Gary Tegtmeier, Charles Wood

Nebraska Center for Virology: Faculty Publications

The human immunodeficiency virus (HIV) p24 core protein is one of the most immunogenic of HIV structural proteins. Infected individuals develop high titers of antibodies against p24 early in infection, which makes anti-p24 antibodies important serological markers. However, despite the clinical importance of the anti-p24 response, no systematic study to characterize the antigenic domains on the p24 protein has been reported. We report here on the use of 12 overlapping fragments of the HIV type 1 p24 protein, synthesized in bacteria as TrpE/Gag fusion proteins, to identify at least two and possibly three antigenic domains on the p24 protein. In …

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Effect Of Milk On Fibronectin And Collagen Type I Binding To Staphylococcus Aureus And Coagulase-Negative Staphylococci Isolated From Bovine Mastitis, J. Miedzobrodzki, A. S. Naidu, J. L. Watts, Pawel Ciborowski, K. Palm Mar 1989

Effect Of Milk On Fibronectin And Collagen Type I Binding To Staphylococcus Aureus And Coagulase-Negative Staphylococci Isolated From Bovine Mastitis, J. Miedzobrodzki, A. S. Naidu, J. L. Watts, Pawel Ciborowski, K. Palm

Nebraska Center for Virology: Faculty Publications

Tryptic soy broth (TSB)-grown cells of Staphylococcus aureus isolated from acute and chronic bovine mastitis bound mainly 125I-fibronectin (125I-Fn), whereas strains of nine species of coagulase-negative staphylococci showed a predominant interaction with 125I-collagen (125I-Cn) type I. A particle agglutination assay (PAA) was used to examine the interaction of coagulase-negative staphylococci with 1251-Fn and 125I-Cn immobilized on latex. All 368 coagulase-negative staphylococci demonstrated high 125I-Cn and moderate to low 125I-Fn interactions in the PAA. Cn-PAA reactivity was high among strains of Staphylococcus xylosus (84.2%), Staphylococcus simulans (77.8%), Staphylococcus epidermidis (76.7%), and …

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Transactivation Of Human Immunodeficiency Virus Promoter By Human Herpesvirus 6, Rebecca Horvat, Charles Wood, N. Balachandran Feb 1989

Transactivation Of Human Immunodeficiency Virus Promoter By Human Herpesvirus 6, Rebecca Horvat, Charles Wood, N. Balachandran

Nebraska Center for Virology: Faculty Publications

Patients with acquired immunodeficiency syndrome (AIDS) are often infected with a number of other heterologous viruses in addition to the initial human immunodeficiency virus (HIV) infection, and these agents could act as potential reactivating agents of latent HIV. A new antigenically distinct herpesvirus, designated human herpesvirus 6 (HHV-6), has recently been isolated from patients with AIDS and has been shown to infect a number of different human cells, specifically human T cells, B cells, and glial cells. Since these are some of the same cells that harbor the AIDS virus, it is quite important to determine any interaction between this …

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Use Of Trpe/Gag Fusion Proteins To Characterize Immunoreactive Domains On The Human Immunodeficiency Virus Type 1 Core Protein, Michael Windheuser, Gary Tegtmeier, Charles Wood Jan 1989

Use Of Trpe/Gag Fusion Proteins To Characterize Immunoreactive Domains On The Human Immunodeficiency Virus Type 1 Core Protein, Michael Windheuser, Gary Tegtmeier, Charles Wood

Nebraska Center for Virology: Faculty Publications

The human immunodeficiency virus (HIV) p24 core protein is one of the most immunogenic of HIV structural proteins. Infected individuals develop high titers of antibodies against p24 early in infection, which makes anti-p24 antibodies important serological markers. However, despite the clinical importance of the anti-p24 response, no systematic study to characterize the antigenic domains on the p24 protein has been reported. We report here on the use of 12 overlapping fragments of the HIV type 1 p24 protein, synthesized in bacteria as TrpE/Gag fusion proteins, to identify at least two and possibly three antigenic domains on the p24 protein. In …

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Isolation And Characterization Of Monoclonal Antibodies Directed Against Plant Plasma Membrane And Cell Wall Epitopes: Identification Of A Monoclonal Antibody That Recognizes Extensin And Analysis Of The Process Of Epitope Biosynthesis In Plant Tissues And Cell Cultures, David J. Meyer, Claudio L. Alfonso, David W. Galbraith Jul 1988

Isolation And Characterization Of Monoclonal Antibodies Directed Against Plant Plasma Membrane And Cell Wall Epitopes: Identification Of A Monoclonal Antibody That Recognizes Extensin And Analysis Of The Process Of Epitope Biosynthesis In Plant Tissues And Cell Cultures, David J. Meyer, Claudio L. Alfonso, David W. Galbraith

Papers in Microbiology

Membranes from tobacco cell suspension cultures were used as antigens for the preparation of monoclonal antibodies. Use of solid phase and indirect immunofluorescence assays led to the identification of hybridomas producing antibodies directed against cell surface epitopes. One of these monoclonal antibodies (ll.D2) was found to recognize a molecular species which on two-dimensional analysis (using nonequilibrium pH-gradient electrophoresis and SDS-PAGE) was found to have a high and polydisperse molecular mass and a very basic isoelectric point. This component was conspicuously labeled by [3H]proline in vivo. The monoclonal antibody cross-reacted with authentic tomato extensin, but not with potato lectin nor larch …

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Reliable Detection Of Individuals Seropositive For The Human Immunodeficiency Virus (Hiv) By Competitive Immunoassays Using Escherichia Coli - Expressed Hiv Structural Proteins, G. J. Dawson, J. S. Heller, Charles Wood, R. A. Gutierrez, J. S. Webber, J. C. Hunt, S. A. Hojvat, D. Senn, S. G. Devare, R. H. Decker Jan 1988

Reliable Detection Of Individuals Seropositive For The Human Immunodeficiency Virus (Hiv) By Competitive Immunoassays Using Escherichia Coli - Expressed Hiv Structural Proteins, G. J. Dawson, J. S. Heller, Charles Wood, R. A. Gutierrez, J. S. Webber, J. C. Hunt, S. A. Hojvat, D. Senn, S. G. Devare, R. H. Decker

Nebraska Center for Virology: Faculty Publications

We molecularly cloned the gag and env genes of the human immunodeficiency virus (HIV) and expressed fragments of these genes in Escherichia coli. Using the recombinant core and envelope proteins, we developed two competitive immunoassays (CIAs). Samples that recognized either the envelope or core proteins were considered positive for antibodies to HIV. This test system was comparable with western blot in detecting antibodies in patients with AIDS or AIDS-related complex that were repeatably reactive in the HIV screening test. All 360 individuals who were positive by western blot were positive by the CIA. A total of 844 samples repeatably …

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Can We Guarantee The Safety Of Genetically Engineered Organisms In The Environment?, Kathleen H. Keeler, Frances E. Sharples Jan 1988

Can We Guarantee The Safety Of Genetically Engineered Organisms In The Environment?, Kathleen H. Keeler, Frances E. Sharples

School of Biological Sciences: Faculty Publications

Can we guarantee the safety of genetically engineered organisms in the environment? To anticipate my remarks, the answer to the title question is “No, we cannot guarantee the safety of genetically engineered organisms released into the environment.” Indeed, it is a tenet of the scientific method that nothing can be proved, only disproved. Thus, we can never show that a release will be safe. We could only show that it would be unsafe, if that were the case. However, if the question is posed differently, for example, can we safely release genetically engineered organisms into the environment?, the answer is …

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Activation Of The Human Immunodeficiency Virus By Herpes Simplex Virus Type 1, Jeffrey M. Ostrove, John Leonard, Karen E. Weck, Arnold B. Rabson, Howard Gendelman Dec 1987

Activation Of The Human Immunodeficiency Virus By Herpes Simplex Virus Type 1, Jeffrey M. Ostrove, John Leonard, Karen E. Weck, Arnold B. Rabson, Howard Gendelman

Nebraska Center for Virology: Faculty Publications

Herpes simplex virus type 1 (HSV-1) and some of its immediate-early genes stimulate expression of the human immunodeficiency virus (HIV) long terminal repeat (LTR) sequences and the replication of HIV itself. To demonstrate this, the HIV LTR was linked to the indicator gene chloramphenicol acetyltransferase (CAT) and transfected into Vero cells with or without the trans-activating gene (tat) of HIV. Infection of these cells with HSV-1 strain KOS or temperature-sensitive mutant tsB2l or tsE6 resulted in a large increase in CAT activity in the absence of tat and further augmentation in the presence of tat. This stimulation was seen at …

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The Glycoprotein Toxin Of Bacillus Thuringiensis Subsp. Israelensis Indicates A Lectinlike Receptor In The Larval Mosquito Gut, Ganapathy Muthukumar, Kenneth Nickerson Nov 1987

The Glycoprotein Toxin Of Bacillus Thuringiensis Subsp. Israelensis Indicates A Lectinlike Receptor In The Larval Mosquito Gut, Ganapathy Muthukumar, Kenneth Nickerson

Papers in Microbiology

The mosquito-active protein crystals produced by Bacillus thuringiensis subsp. israelensis contain covalently attached aminosugars which are critical for their larvicidal activity. The 50% lethal concentrations toward Aedes aegypti larvae were increased up to 10-fold by mild periodate treatment, up to 40-fold by forming the protein crystals in the presence of tunicamycin, and up to 7-fold by the presence during the mosquito bioassays of N-acetylglucosamine or its trimer, triacetylchitotriose. Periodate-treated crystals and crystals formed in the presence of tunicamycin had greatly reduced binding capacities for wheat germ agglutinin, an Nacetylglucosamine- specific lectin. These results suggest that the B. thuringiensis subsp. …

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Temperature-Dependent Kinetic Variation Among Phosphoglucose Isomerase Allozymes From The Wing-Polymorphic Water Strider, Limnoporus Canaliculatusl, Anthony J. Zera Aug 1987

Temperature-Dependent Kinetic Variation Among Phosphoglucose Isomerase Allozymes From The Wing-Polymorphic Water Strider, Limnoporus Canaliculatusl, Anthony J. Zera

Anthony Zera Publications

Phosphoglucose isomerase (PGI) allozymes were isolated from the wing-polymorphic water strider, Lirnnoporus canaliculatus, and were characterized biochemically with respect to temperature-dependent kinetic and thermostability properties. At higher temperatures, the allozymes exhibited significant differences in Michaelis constant (Km) values for substrates of both the forward and reverse reaction directions. Results were consistent with expectations of adaptive kinetic differentiation based on the latitudinal variation of PGI allele frequencies. PGI genotypes also differed with regard to maximal velocity (Vmax)/Km ratios at higher temperatures. These differences were due primarily, if not exclusively, to allozyme-dependent variation in K …

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Structural Disulfide Bonds In The Bacillus Thuringiensis Subsp. Israelensis Protein Crystal, Graham A. Couche, Mary A. Pfannenstiel, Kenneth W. Nickerson Jul 1987

Structural Disulfide Bonds In The Bacillus Thuringiensis Subsp. Israelensis Protein Crystal, Graham A. Couche, Mary A. Pfannenstiel, Kenneth W. Nickerson

Papers in Microbiology

We examined disulfide bonds in mosquito larvicidal crystals produced by Bacillus thuringiensis subsp. israelensis. Intact crystals contained 2.01 x 10-8 mol of free sulfhydryls and 3.24 x 10--8 mol of disulfides per mg of protein. Reduced samples of alkali-solubilized crystals resolved into several proteins, the most prominent having apparent molecular sizes of 28, 70, 135, and 140 kilodaltons (kDa). Non-reduced samples contained two new proteins of 52 and 26 kDa. When reduced, both the 52- and 26-kDa proteins were converted to 28-kDa proteins. Furthermore, both bands reacted with antiserum prepared against reduced 28-kDa protein. Approximately 50% of …

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