Microbiology Commons^™

Differential Lipid Biosynthesis Underlies A Tradeoff Between Reproduction And Fl Ight Capability In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera

Anthony Zera Publications

The biochemical basis of life-history tradeoffs is a poorly studied aspect of life-history evolution. We used radiotracer and endocrine approaches to investigate the extent to which morphs of a wing-polymorphic insect differ in the biosynthesis of lipid classes important for dispersal capability vs. reproduction (ovarian growth). The flightcapable genotype of Gryllus firmus biosynthesized a greater amount of total lipid and triglyceride (main flight fuel), which was preferentially allocated to somatic tissue during early adulthood. By contrast, the fl ightless genotype biosynthesized a significantly greater amount of phospholipid (important in egg development), which was preferentially allocated to ovaries. Topical application of …

Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden

Biochemistry and Microbiology

Morphological alterations have been shown to occur in Drosophila melanogaster when function of Hsp90 (heat shock 0-kDa protein 1α, encoded by Hsp83) is compromised during development1. Genetic selection maintains the altered phenotypes in subsequent generations1. Recent experiments have shown, however, that phenotypic variation still occurs in nearly isogenic recombinant inbred strains of Arabidopsis thaliana2. Using a sensitized isogenic D. melanogaster strain, iso-KrIf-1, we confirm this finding and present evidence supporting an epigenetic mechanism for Hsp90’s capacitor function, whereby reduced activity of Hsp90 induces a heritably altered chromatin state. The altered chromatin state is evidenced by ectopic expression …

Shar-Pei Mediates Cell Proliferation Arrest During Imaginal Disc Growth In Drosophila, Madhuri Kango-Singh, Riitta Nolo, Chunyao Tao, Patrik Verstreken, P. Robin Hiesinger, Hugo J. Bellen, Georg Halder

Biology Faculty Publications

During animal development, organ size is determined primarily by the amount of cell proliferation, which must be tightly regulated to ensure the generation of properly proportioned organs. However, little is known about the molecular pathways that direct cells to stop proliferating when an organ has attained its proper size. We have identified mutations in a novel gene, shar-pei, that is required for proper termination of cell proliferation during Drosophila imaginal disc development. Clones of shar-pei mutant cells in imaginal discs produce enlarged tissues containing more cells of normal size. We show that this phenotype is the result of both …

The Cd154/Cd40 Interaction Required For Retrovirus-Induced Murine Immunodeficiency Syndrome Is Not Mediated By Upregulation Of The Cd80/Cd86 Costimulatory Molecules, Kathy A. Green, W. James Cook, Arlene H. Sharpe, William R. Green

Dartmouth Scholarship

C57BL/6 (B6) mice infected with LP-BM5 retroviruses develop disease, including an immunodeficiency similar to AIDS. This disease, murine AIDS (MAIDS), is inhibited by in vivo anti-CD154 monoclonal antibody treatment. The similar levels of insusceptibility of CD40^−/− and CD154^−/− B6 mice indicate that CD154/CD40 molecular interactions are required for MAIDS. CD4⁺ T and B cells, respectively, provide the CD154 and CD40 expression needed for MAIDS induction. Here, the required CD154/CD40 interaction is shown to be independent of CD80 and CD86 expression: CD80/CD86^−/− B6 mice develop MAIDS after LP-BM5 infection.

Leiomyosarcoma Presenting As A Spontaneously Ruptured Renal Tumor-Case Report, Mohammad Moazzam, M Hammad Ather, Akber S. Hussainy

Department of Pathology and Laboratory Medicine

Background:
Ruptured renal neoplasms can be a catastrophic clinical presentation. Angiomyolipoma is the commonest renal tumor which presents in this fashion. Renal sarcomas are rare renal neoplasms. Renal leiomyosarcomas are the most common histological subtype of renal sarcomas, accounting for approximately 50-60% of the reported cases. These tumors are usually peripherally located and appear to arise from either the renal capsule or smooth muscle tissue in the renal pelvic wall.
Case presentation:
A 70 years old male, with hypertension and ischemic disease, developed acute left flank pain. The general physician evaluated this using ultrasound, which showed a solid left renal …

The Structure And Evolution Of The Major Capsid Protein Of A Large, Lipid-Containing Dna Virus, Narayanasamy Nandhagopal, Alan Simpson, James Gurnon, Xiadong Yan, Timothy Baker, Michael V. Graves, James L. Van Etten, Michael Rossman

Nebraska Center for Virology: Faculty Publications

Paramecium bursaria Chlorella virus type 1 (PBCV-1) is a very large, icosahedral virus containing an internal membrane enclosed within a glycoprotein coat consisting of pseudohexagonal arrays of trimeric capsomers. Each capsomer is composed of three molecules of the major capsid protein, Vp54, the 2.0-Å resolution structure of which is reported here. Four N-linked and two O-linked glycosylation sites were identified. The N-linked sites are associated with nonstandard amino acid motifs as a result of glycosylation by virus-encoded enzymes. Each monomer of the trimeric structure consists of two eight-stranded, antiparallel β-barrel, “jelly-roll” domains related by a pseudo-sixfold rotation. The fold of …

Unique Epitope Of Bovine Immunodeficiency Virus Gag Protein Spans The Cleavage Site Between P16Ma And P2l, Ming Lu, Ling Zheng, Kathy Mitchell, Sanjay Kapil, Charles Wood, Harish Minocha

Nebraska Center for Virology: Faculty Publications

Bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV) are closely related bovine lentiviruses that are difficult to distinguish by presently available diagnostic methods. Recently, in our laboratory, a monoclonal antibody (MAb; MAb 10H1) against the BIV Gag protein identified a differential epitope, located at the 6.4-kDa N terminus of a 29-kDa Gag capsid protein, which was absent in JDV. To define the essential amino acids of the epitope, a series of primers within the 163 bp of DNA corresponding to the 6.4-kDa protein were designed. The full-length 163-bp DNA fragment and the smaller DNA fragments with deletions were amplified …

Mechanism Of Toxt-Dependent Transcriptional Activation At The Vibrio Cholerae Tcpa Promoter, Robin R. Hulbert, Ronald K. Taylor

Dartmouth Scholarship

The AraC homolog ToxT coordinately regulates virulence gene expression in Vibrio cholerae. ToxT is required for transcriptional activation of the genes encoding cholera toxin and the toxin coregulated pilus, among others. In this work we focused on the interaction of ToxT with the tcpA promoter and investigated the mechanism of ToxT-dependent transcriptional activation at tcpA. Deletion analysis showed that a region from −95 to +2 was sufficient for ToxT binding and activation, both of which were simultaneously lost when the deletion was extended to −63. A collection of point mutations generated by error-prone PCR revealed two small regions required …

Review Of Dispersal. Based On A Conference Held In Roscoff, France, 23 April–1 May 1999., Anthony J. Zera

Anthony Zera Publications

Edited by Jean Clobert, Etienne Danchin, André A Dhondt, and James D Nichols. Oxford and New York: Oxford University Press.

Dispersal is a phenomenon of central importance in ecology and evolution. Yet many of its fundamental aspects remain poorly understood or barely investigated. This excellent, broad-ranging volume is a collection of 26 short reviews derived from a Centre National de la Recherche (CNRS)-National Science Foundation (NSF) sponsored workshop held in 1999. As stated by the editors, this book is mainly comprised of “reviews and more theoretical approaches, with a limited number of empirical examples” (p. xx) on dispersal.

I highly …

Eye Suppression, A Novel Function Of Teashirt, Requires Wingless Signaling, Amit Singh, Madhuri Kango-Singh, Y. Henry Sun

Biology Faculty Publications

Teashirt (tsh) encodes a Drosophila zinc-finger protein. Misexpression of tsh has been shown to induce ectopic eye formation in the antenna. We report that tsh can suppress eye development. This novel function of tsh is due to the induction of homothorax (hth), a known repressor of eye development, and requires Wingless (WG) signaling. Interestingly, tsh has different functions in the dorsal and ventral eye, suppressing eye development close to the ventral margin, while promoting eye development near the dorsal margin. It affects both growth of eye disc and retinal cell differentiation.

Microbial Cellulose Utilization: Fundamentals And Biotechnology, Lee R. Lynd, Paul J. Weimer, Willem H. Van Zyl, Isak S. Pretorius

Dartmouth Scholarship

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial …

Investigating The Mechanism Of Acoustically Activated Uptake Of Drugs From Pluronic Micelles, Ghaleb A. Husseini, Christopher M. Runyan, William G. Pitt

Faculty Publications

Background

This paper examines the mechanism of ultrasonic enhanced drug delivery from Pluronic micelles. In previous publications by our group, fluorescently labeled Pluronic was shown to penetrate HL-60 cells with and without the action of ultrasound, while drug uptake was increased with the application of ultrasound.

Methods

In this study, the amount of uptake of two fluorescent probes, Lysosensor Green (a pH-sensitive probe) and Cell Tracker Orange CMTMR (a pH-independent probe), was measured in HL-60 and HeLa cells.

Results

The results of our experiments show that the increase in drug accumulation in the cells as a result of ultrasonication is …

Human Exposure To Herpesvirus B–Seropositive Macaques, Bali, Indonesia, Gregory A. Engel, Lisa Jones-Engel, Michael A. Schillaci, Komang Gde Suaryana, Artha Putra, Agustin Fuentes, Richard Henkel

All Faculty Scholarship for the College of the Sciences

Herpesvirus B (Cercopithecine herpesvirus 1) has been implicated as the cause of approximately 40 cases of meningoencephalitis affecting persons in direct or indirect contact with laboratory macaques. However, the threat of herpesvirus B in nonlaboratory settings worldwide remains to be addressed. We investigated the potential for exposure to herpesvirus B in workers at a “monkey forest” (a temple that has become a tourist attraction because of its monkeys) in Bali, Indonesia. In July 2000, 105 workers at the Sangeh Monkey Forest in Central Bali were surveyed about contact with macaques (Macaca fascicularis). Nearly half of those interviewed had …

The Uv (Ribotoxic) Stress Response Of Human Keratinocytes Involves The Unexpected Uncoupling Of The Ras-Extracellular Signal-Regulated Kinase Signaling Cascade From The Activated Epidermal Growth Factor Receptor, Mihail S. Iordanov, Remy J. Choi, Olga P. Ryabinina, Thanh-Hoai Dinh, Robert K. Bright, Bruce E. Magun

CUP Faculty Research

In mammals, UVB radiation is of biological relevance primarily for the cells of the epidermis. We report here the existence of a UVB response that is specific for proliferating human epidermal keratinocytes. Unlike other cell types that also display a UVB response, keratinocytes respond to UVB irradiation with a transient but potent downregulation of the Ras-extracellular signal-regulated kinase (ERK) signaling cascade. The downregulation of ERK precedes a profound decrease in the steady-state levels of cyclin D1, a mediator of the proliferative action of ERK. Keratinocytes exhibit high constitutive activity of the Ras-ERK signaling cascade even in culture medium lacking supplemental …

Effect Of Guanosine Tetraphosphate On Growth Rate And Stable Rna Synthesis In Escherichia Coli, Heather Anne Quintanilla

Theses and Dissertations - UTB/UTPA

Guanosine tetraphosphate (ppGpp) is a good candidate for a stable RNA synthesis regulator at different growth rates because: high ppGpp levels present during the stringent response are known to inhibit stable RNA synthesis, and there is an inverse correlation between ppGpp concentration and stable RNA synthesis at different growth rates. A system was constructed allowing the user to control intracellular ppGpp levels within the range characteristic of exponentially growing strains, while not allowing cells to adjust ppGpp in response to environmental changes. E. coli strains were transformed with a plasmid containing a truncated relA allele to provide ppGpp. Results show …

Sodium Dodecyl Sulfate Hypersensitivity Of Clpp And Clpb Mutants Of Escherichia Coli, Soumitra Rajagopal, Narasimhan Sudarsan, Kenneth W. Nickerson

Papers in Microbiology

We studied the hypersensitivity of clpP and clpB mutants of Escherichia coli to sodium dodecyl sulfate (SDS). Both wild-type E. coli MC4100 and lon mutants grew in the presence of 10% SDS, whereas isogenic clpP and clpB single mutants could not grow above 0.5% SDS and clpA and clpX single mutants could not grow above 5.0% SDS. For wild-type E. coli, cellular ClpP levels as determined by Western immunoblot analysis increased ca. sixfold as the levels of added SDS increased from 0 to 2%. Capsular colanic acid, measured as uronic acid, increased ca. sixfold as the levels of added …

Csf Oligoclonal Bands In Multiple Sclerosis, I Siddiqui, S Aleem, N Kayani, S Baig

Department of Pathology and Laboratory Medicine

Objective:
To study the significance of oligoclonal bands in neurological disorders, specifically in Multiple Sclerosis (MS).
Methods:
The study was designed to assess the sensitivity and specificity of the test methodology of CSF electrophoresis by performing the retrospective analysis of CSF samples sent for oligoclonal bands (OCB). A total of 603 samples were received by the Clinical Laboratories, Department of Pathology of The Aga Khan University, during a period of 54 months (January 1993-June 1997). All of these samples were analyzed by performing CSF protein electrophoresis. One hundred thirty three out of 603 samples showed evidence of OCB. Out …

Characterization Of Pathogenic Mutations In 21-Hydroxylase Gene Of Pakistani Patients With Congenital Adrenal Hyperplasia And Their Family Members--A Preliminary Report, A H. Khan, M I. Nasir, T Moatter

Department of Pathology and Laboratory Medicine

Objective:
To characterize specific mutations within the 21-hydroxylase gene (CYP21-B) using ARMS-PCR assay in patients with congenital adrenal hyperplasia (CAH) and to compare it with that reported in other populations.
Subjects and Methods:
Five families, having an index case with CAH diagnosed on the basis of clinical and biochemical findings volunteered to give blood samples for analysis. A strategy, based on ARMS-PCR (Amplified Refractory Mutation System) was employed for the detection of mutations in 21-hydroxylase gene. The products of ARMS-PCR were resolved on agarose gels and the PCR products were visualized over ultra violet illumination.
Results:
Twenty-six specimens were analyzed …

The Deadly Trypanosome: Understanding The Parasite That Causes Sleeping Sickness, Patricia E. Mancini

Bridgewater Review

No abstract provided.

Mechanisms Of Autoantigen Cleavage During Cell Death, Xiwei Wu

Loma Linda University Electronic Theses, Dissertations & Projects

Specific intracellular autoantigens targeted by autoantibodies in systemic autoimmune and chronic inflammatory diseases undergo posttranslational modifications, such as cleavage, during cell death that could potentially enhance their immunogenicity. In light of the increasing interest in the immunological consequences of defective clearance of apoptotic cells, we explored whether autoantigens cleaved during apoptosis undergo an additional wave of proteolysis as apoptosis progresses to secondary necrosis in the absence of phagocytosis. Jurkat T cells treated with different apoptosis inducers underwent a rapid apoptosis that gradually progressed to secondary necrosis. During the initial apoptotic stages, several nuclear autoantigens, including PARP, Topo I, and LEDGF/p75 …

Retrograde Transport Of Transmissible Mink Encephalopathy Within Descending Motor Tracts, Jason C. Bartz, Anthony E. Kincaid, Richard A. Bessen

Nebraska Center for Virology: Faculty Publications

The spread of the abnormal conformation of the prion protein, PrP^Sc, within the spinal cord is central to the pathogenesis of transmissible prion diseases, but the mechanism of transport has not been determined. For this report, the route of transport of the HY strain of transmissible mink encephalopathy (TME), a prion disease of mink, in the central nervous system following unilateral inoculation into the sciatic nerves of Syrian hamsters was investigated. PrP^Sc was detected at 3 weeks postinfection in the lumbar spinal cord and ascended to the brain at a rate of approximately 3.3 mm per day. …

The Diversity And Abundance Of Parasites In Age Groups Of Yellow Perch In Lake Bemidji, Mn Applied To A Whittaker Curve, Kelly J. Main

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Ornithine Decarboxylase Encoded By Chlorella Virus Pbcv-1, Tiara A. Morehead, James R. Gurnon, Byron Adams, Kenneth Nickerson, Lisa A. Fitzgerald, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

Sequence analysis of the 330-kb genome of chlorella virus PBCV-1 revealed an open reading frame, A207R, which encodes a protein with 37–41% amino acid identity to ornithine decarboxylase (ODC) from many eukaryotic organisms. The a207r gene was cloned and the protein was expressed as a His-A207R fusion protein in Escherichia coli. The recombinant protein catalyzes pyridoxal 5’-phosphate-dependent decarboxylation of ornithine to putrescine, the first step in the polyamine biosynthetic pathway The enzyme has a pH optimum of 9.0 and a temperature optimum of 42°C, and it requires dithiothreitol for maximal activity. The enzyme has a Km, for ornithine of …

Identification Of Neutralizing And Nonneutralizing Epitopes In The Porcine Reproductive And Respiratory Syndrome Virus Gp5 Ectodomain, M. Ostrowski, J. A. Galeota, A. M. Jar, K. B. Platt, Fernando A. Osorio, O. J. Lopez

Nebraska Center for Virology: Faculty Publications

After infection of swine with porcine reproductive and respiratory syndrome virus (PRRSV), there is a rapid rise of PRRSV-specific nonneutralizing antibodies (NNA), while neutralizing antibodies (NA) are detectable not sooner than 3 weeks later. To characterize neutralizing epitopes, we selected phages from a 12-mer phage display library using anti-PRRSV neutralizing monoclonal antibody (MAb) ISU25-C1. In addition, phages carrying peptides recognized by swine antibodies with high seroneutralizing titer were isolated after subtracting from the library those clones binding to swine anti-PRRSV serum with no neutralizing activity. Two epitopes located in the ectodomain of PRRSV GP5 were identified. One of these epitopes, …

The Creation Of A Knock-Out Mutation Of A Gamma And Beta Carbonic Anhydrase In Deinococcus Radiodurans And The Construction Of Expression Plasmids, Amy E. Noles

Honors Capstones

No abstract provided.

Hla-Cw*04 And Hepatitis C Virus Persistence, Chloe L. Thio, Xiaojiang Gao, James J. Goedert, David Vlahov, Kenrad E. Nelson, Margaret Hilgartner, Stephen J. O'Brien, Peter Karacki, Jacquie Astemborski, Mary Carrington, David L. Thomas

Biology Faculty Articles

In studies of acute hepatitis C virus (HCV) infection, the early host immune response is one of the determinants of viral persistence. The class I human leukocyte antigens (HLA), which present foreign antigen to cytolytic T cells, are integral components of this response. We hypothesized that the highly polymorphic HLA genes affect the outcome of an HCV infection. To test this hypothesis, we molecularly typed 231 persons with well-documented clearance of an HCV infection and 444 matched persistently infected persons. HLA-A*1101 (odds ratio [OR], 0.49; 95% confidence interval [95% CI], 0.27 to 0.89), HLA-B*57 (OR, 0.62; 95% CI, 0.39 to …

Affinity Purification And Characterization Of E. Coli Molecular Chaperones, Seung-Hee Nam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The molecular chaperones are a group of proteins that are effective in vitro and in vivo folding aids and show a well documented affinity for proteins lacking tertiary structure.

Heat-induced Escherichia coli BL21 cell lysate (10 mg protein) was applied to immobilized ɑ-casein (45 mg/g beads) or β-casein (30 mg/g beads) column. After removing a majority of nonspecifically bound proteins with 1 M NaCl, the molecular chaperones were eluted with cold water, 1 mM Mg-ATP, or 6 M urea. Western analysis identified five Escherichia coli molecular chaperones including DnaK, DnaJ, GrpE, GroEL, and GroES. Among samples, ATP eluates showed the …

Tryptophan Catabolism In Brevibacterium Linens Bl2, Madhavi Ummadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent studies suggest aromatic amino acid catabolism by starter lactococci and flavor adjunct bacteria have a significant impact on off-flavor development during Cheddar cheese ripening. We hypothesized that a flavor adjunct bacterium, Brevibacterium linens BL2, produces off-flavor compounds from aromatic amino acid metabolism that will have a detrimental impact on cheese flavor.

The mechanism of tryptophan (Trp) catabolism in Brevibacterium linens BL2, was investigated in a chemically defined medium during incubation in laboratory conditions (no carbohydrate, pH 6.50, 220 rpm, 25°C) and cheese-like conditions (no carbohydrate, 4% NaCl, static incubation, l5°C). In laboratory conditions, metabolic studies and enzyme assays confirmed …

Comparison Of Tnf-A Levels Produced By Macrophages Treated With Brucella Abortus And Escherichia Coli Lps, Tajie Harris

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Susceptibility Of Sensory Neurons To Apoptosis Following Infection By Bovine Herpesvirus Type 1, Gustavo A. Delhon, Marcelo J. Gonzalez, Pablo R. Murcia

Nebraska Center for Virology: Faculty Publications

Like other members of the alpha subfamily of herpesviruses, bovine herpesvirus type 1 (BHV-1) establishes latent infections in sensory neurons. BHV-1 induces apoptosis in lymphoid cells in vivo and in epithelial cell lines, but the ability of BHV- 1 to induce apoptosis in sensory neurons remains unknown. In this report, the susceptibility of rabbit ganglionic neurons to infection by BHV-1 was examined in vitro and in vivo. Following infection of cultured neurons with BHV-1, hallmarks of apoptosis such as chromatin condensation, DNA fragmentation and membrane blebbing were detected. The appearance of these changes was preceded by active viral DNA …