Microbiology Commons^™

Investigations Into The Innate Resistance Of The Tick, Dermacentor Variabilis, When Challenged With The Bacterium, Escherichia Coli, Shane Michael Ceraul

Biological Sciences Theses & Dissertations

In addition to the soluble response, many invertebrates control bacterial infections by means of phagocytosis or melanotic encapsulation. In some insects, Escherichia coli growth is reported to be inhibited by aggregation/encapsulation. Soluble and phagocytic responses to bacterial challenge have been reported in ticks, but evidence of an aggregation/encapsulation response was reported only for inanimate (araldite) implants. This study was done to determine how ticks control infection by E. coli. Ticks were challenged by direct inoculation of bacteria into the hemocoel cavity. Using plate counts, no viable E. coli were detected I hour post-inoculation. A direct fluorescence assay (DF A) …

Differentiation Of Two Bovine Lentiviruses By A Monoclonal Antibody On The Basis Of Epitope Specificity, Ling Zheng, Shucheng Zhang, Charles Wood, Sanjay Kapil, Graham E. Wilcox, Thomas A. Loughlin, H. C. Minocha

Nebraska Center for Virology: Faculty Publications

Bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV) are bovine lentiviruses that are closely related genetically. A recombinant fusion protein containing the capsid protein of BIV expressed in Escherichia coli was used to immunize mice and produce monoclonal antibodies. Six hybridomas specific for BIV capsid protein were identified, and one antibody, designated 10H1, was characterized further. Competitive binding assays were performed to analyze the topography of antigenic determinants by enzyme-linked immunosorbent assay and demonstrated the existence of at least three distinct antigenic determinants on capsid protein. The monoclonal antibody reacted specifically with both BIV capsid and the recombinant fusion …

Genetic And Diurnal Variation In The Juvenile Hormone Titer In A Wing-Polymorphic Cricket: Implications For The Evolution Of Life Histories And Dispersal, Anthony J. Zera, Gretchen Cisper

Anthony Zera Publications

The wing-polymorphic cricket, Gryllus firmus, contains (1) a flight-capable morph (LW_f) with long wings and functional flight muscles, (2) a flightless morph with reduced wings and underdeveloped flight muscles (SW), and (3) a flightless morph with histolyzed flight muscles but with fully developed wings (LW_h). The LW_f morph differed genetically from the SW morph and phenotypically from the LW_h morph in the size of flight muscles, ovarian growth during the first week of adulthood, and the hemolymph titer of juvenile hormone (JH). This is the first study to document that phenotypes that differ …

The Endocrine-Genetic Basis Of Life-History Variation: The Relationship Between The Ecdysteroid Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket Gryllus Firmus, Anthony J. Zera, Justin Bottsford

Anthony Zera Publications

The hormonal basis of variation in life-history traits is a poorly studied topic in life-history evolution. An important step in identifying the endocrine-genetic causes of life-history variation is documenting statistical and functional associations between hormone titers and genotypes/phenotypes that vary in life-history traits. To this end, we compared the blood ecdysteroid titer and the mass of the ovaries during the first week of adulthood among a flight-capable morph and two fl ightless morphs of the wing-polymorphic cricket Gryllus firmus. Ecdysteroids are a group of structurally related hormones that regulate many important aspects of reproduction in insects. Both the ecdysteroid …

A Common Pattern Of Somite Cell Rotation In Three Species Of Pipidae, Shou-Yuan Fan, Rafael O. De Sá, Gary P. Radice

Biology Faculty Publications

During amphibian somitogenesis, presumptive myotome cells change shape from round or polygonal to elongated and aligned parallel to the notochord (for reviews see Radice, et al., 1989; Keller, 2000). Although the final orientation of myotomal cells is always axial, the movements that achieve this final arrangement can differ greatly between species. The simplest movement is that seen in Bombina variegata, Pelobates fuscus, and Bufo bufo (Brustis et al., 1976; Brustis, 1979; Kielbowna, 1981 ). In these anurans, after segmentation myotomal cells simply elongate along the embryo’s anteroposterior axis. The urodeles Ambystoma mexicanum and Pleurodeles waltl have a very different pattern; …

Nuclear Export Of 60s Ribosomal Subunits Depends On Xpo1p And Requires A Nuclear Export Sequence-Containing Factor, Nmd3p, That Associates With The Large Subunit Protein Rpl10p, Olivier Gadal, Daniela Strau, Jacques Kessl, Bernard Trumpower

Dartmouth Scholarship

Nuclear export of ribosomes requires a subset of nucleoporins and the Ran system, but specific transport factors have not been identified. Using a large subunit reporter (Rpl25p-eGFP), we have isolated several temperature-sensitive ribosomal export (rix) mutants. One of these corresponds to the ribosomal protein Rpl10p, which interacts directly with Nmd3p, a conserved and essential protein associated with 60S subunits. We find that thermosensitive nmd3 mutants are impaired in large subunit export. Strikingly, Nmd3p shuttles between the nucleus and cytoplasm and is exported by the nuclear export receptor Xpo1p. Moreover, we show that export of 60S subunits is Xpo1p dependent. We …

Genetic And Biological Variation In Equine Infectious Anemia, Michael Belshan, Prasith Baccum, J. Lindsay Oaks, Brett A. Sponseller, Sean C. Murphy, James Cornette, Susan Carpenter

Nebraska Center for Virology: Faculty Publications

Genetic and biological variation in the regulatory protein Rev of equine infectious anemia virus (EIAV) were examined throughout a clinically dynamic disease course of an experimentally infected pony. Following infection with the virulent EIAV_Wyo, the pony underwent a variable disease course, including an acute fever episode at 12 days postinfection (DPI), multiple recurrent fever episodes until 135 DPI, a prolonged subclinical period, and two late fever episodes. Viral RNA was isolated from the inoculum and sequential sera samples, and the rev exon 2/gp45 overlapping ORFs were amplified, cloned, and sequenced. Novel variants were found throughout infection, and genetic …

Escherichia Coli O157:H7 In Free-Ranging Deer In Nebraska, David G. Renter, Jan M. Sargeant, Scott E. Hygnstrom, Jeff D. Hoffmann, Jerry R. Gillespie

School of Natural Resources: Faculty Publications

In order to determine the prevalence and distribution of the human pathogen, Escherichia coli O157:H7, in free-ranging deer, hunters were asked to collect and submit fecal samples from deer harvested during a regular firearm season (14–22 November 1998). Prior to the season, 47% of the hunters with permits in the southeastern Nebraska (USA) study area indicated a willingness to participate in the study. Approximately 25% of successful hunters in the area submitted deer fecal samples. Escherichia coli O157:H7 was cultured from four (0.25%) of 1,608 total samples submitted. All of the fecal samples that were properly identified (1,426) and all …

Cyanonews (Vol. 16, No. 1, December 2001), Jeff Elhai

CyanoNews

CyanoNews was a newsletter that served the cyanobacteriological community from 1985 to 2003, with content provided by readers (sort of a blog before there were blogs). The newsletter reported new findings from the lab, summaries of recent meetings (often provided by graduate students and post-docs entering the field), positions sought or available, life transitions, a compendium of recent cyanobacteria-related articles, and other items of interest to those who study cyanobacteria.

Humboldt Journal Of Microbiology: Volume 4, Number 1- May 2001, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

Vancomycin-Intermediate Staphylococcus Aureus In A Home Health-Care Patient, Jeffrey C. Hageman, David A. Pegues, Carrie Jepson, Rose Lee Bell, Mary Guinan, Kevin W. Ward, Martin D. Cohen, Janet A. Hindler, Fred C. Tenover, Sigrid K. Mcallister, Molly E. Kellum, Scott K. Fridkin

School of Public Health Faculty Research

To date, four of the eight cases of infection by Staphylococcus aureus with reduced susceptibility to vancomycin (vancomycin-intermediate S. aureus [VISA] or glycopeptideintermediate S. aureus [GISA]) have been reported in the United States (1-3). We report a fifth case of VISA infection in the United States, and the first to occur during home health-care therapy. While all previous VISA strains have been oxacillin resistant, one of the two VISA strains identified in this investigation was oxacillin susceptible.

Phospholipase D1 As A Regulator Of Morphogenesis In Candida Albicans, Carol Anne Baker

MUSC Theses and Dissertations

Phospholipase D (PLD) enzymes play significant roles in phospholipid metabolism, secretion, and lipid signal transduction. The yeast Candida albicans possesses a PLD activity that is designated PLD1. This enzyme has been implicated in the regulation of dimorphic transition. In vivo assays using sphinganine, propranolol, and staurosporine were used to test the importance of phosphatidic acid (PA) and diacylglycerol (DAG), two downstream products of PLDI activity. A concentration of 5 µM sphinganine was sufficient to decrease the appearance of germ tubes with no effect on culture doubling times. However, at higher concentrations sphinganine was inhibitory to cell growth. Propranolol concentrations up …

The Molecular Microbial Ecology And Mechanisms Of Biomarker Degradation In Crude Oil, Fredrick Daniel Bost

MUSC Theses and Dissertations

Biomarkers are structurally complex components of petroleum derived from biological molecular precursors, such as chlorophyll, sterols, and hopanoids (Peters and Moldowan, 1993). The biomarker profile of a crude oil is distinctive and diagnostic, often allowing correlation of an oil to its source rock. Many biomarkers in crude oil are resistant to biodegradation and are used by petroleum geochemists to assess genetic relationships, thermal maturity, and biodegradation. However, the reliability of these biomarkers depends on this recalcitrance to biodegradation. The studies presented here used bacterial enrichment cultures to examine the distribution and extent of biomarker­ degrading activity in aerobic and anaerobic …

Nitric Oxide And Cnidarian-Dinoflagellate Symbioses: Pieces Of A Puzzle, Henry G. Trapido-Rosenthal, Katherine H. Sharp

Arts & Sciences Faculty Publications

The presence of nitric oxide synthase (NOS) activity is demonstrated in the tropical marine cnidarian Aiptasia pallida and in its symbiotic dinoflagellate algae, Symbiodinium bermudense. Enzyme activity was assayed by measuring the conversion of arginine to citrulline. Biochemical characterization of NOS from Aiptasia was characterized with respect to cellular localization, substrate and cofactor requirements, inhibitors, and kinetics. In response to acute temperature shock, anemones retracted their tentacles. Animals subjected to such stress had lower NOS activities than did controls. Treatment with NOS inhibitors caused tentacular retraction, while treatment with the NOS substrate L-arginine inhibited this response to stress, as did …

Activation Of Nf-Κb By Double-Stranded Rna (Dsrna) In The Absence Of Protein Kinase R And Rnase L Demonstrates The Existence Of Two Separate Dsrna-Triggered Antiviral Programs, Mihail S. Iordanov, John Wong, John C. Bell, Bruce E. Magun

CUP Faculty Research

Double-stranded RNA (dsRNA) of viral origin triggers two programs of the innate immunity in virus-infected cells. One is intended to decrease the rate of host cell protein synthesis and thus to prevent viral replication. This program is mediated by protein kinase R (PKR) and by RNase L and contributes, eventually, to the self-elimination of the infected cell via apoptosis. The second program is responsible for the production of antiviral (type I) interferons and other alarmone cytokines and serves the purpose of preparing naive cells for the viral invasion. This second program requires the survival of the infected cell and depends …

Vertical Transmission Of Kaposi's Sarcoma-Associated Herpesvirus, Hamakwa Mantina, Chipepo Kankasa, Winslow Klaskala, Brad Brayfield, James Campbell, Quijiang Du, Ganapati Bhat, Francis Kasolo, Charles Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Little is presently known about the specific routes of transmission of Kaposi’s sarcoma-associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8). To investigate whether this agent might be transmitted vertically from mother to infant, we conducted a study on 89 KSHV seropositive mothers and their newborn infants. Thirteen mothers (14.6%) had KSHV DNA detected in their peripheral blood mononuclear cells (PBMC). Two of 89 samples drawn at birth from infants born to KSHV seropositive mothers had KSHV DNA detectable within their PBMC. These findings suggest that KSHV can be transmitted perinatally, but infrequently. Other routes of transmission such as horizontal transmission remain …

The Investigation Of Rna Viruses Using The Atomic Force Microscope, Michelle Moloney

Theses

The subject of viral entry into, and subsequent progeny virus egress, from cultured cells, has been extensively studied using numerous scientific techniques in fields ranging from cell culture to biochemistry to microscopy. The atomic force microscope (AFM) is a novel, developing instrument with unprecedented capabilities and this study was undertaken to observe enveloped Semliki Forest virus (SFV) and non-enveloped Theiler's Murine Encephalomyelitis virus (TMEV) entry into and egress from cultured cells using the AFM. Virus particle structure of both enveloped and non-enveloped viruses was also directly examined.

Cytopathic effect studies revealed that TMEV's are unable to produce progeny viruses in …

Β-Lactamase: Evolution Of Extended Spectrum Enzymes, Priscilla Shine

Theses

β-Lactam antibiotics are commonly used antimicrobial agents in clinical medicine. Because of their frequent use it is perhaps not surprising that resistance to these agents has increased over the past few decades, thus compromising the therapeutic advantages offered by these agents. The most common cause of resistance to β-lactam-based antibiotics has been the evolution of a group of enzymes known as β-lactamases, which act by inactivating the drug through structural modification. Plasmid-encoded TEM β-lactamases are examples of these hydrolytic enzymes and are associated with the amoxicillin resistance reported in over 50% of all E. coli isolates.

More recently β-lactamase enzymes …

Aquaporin 5-Deficient Mouse Lungs Are Hyperresponsive To Cholinergic Stimulation, Carissa M. Krane, Christopher N. Fortner, Arthur R. Hand, Dennis W. Mcgraw, John N. Lorenz, Susan E. Wert, Jennifer E. Towne, Richard J. Paul, Jeffrey A. Whitsett, Anil G. Menon

Biology Faculty Publications

Although aquaporin 5 (AQP5) is the major water channel expressed in alveolar type I cells in the lung, its actual role in the lung is a matter of considerable speculation. By using immunohistochemical staining, we show that AQP5 expression in mouse lung is not restricted to type I cells, but is also detected in alveolar type II cells, and in tracheal and bronchial epithelium. Aqp5 knockout (Aqp5−/−) mice were used to analyze AQP5 function in pulmonary physiology. Compared with Aqp5+/+ mice, Aqp5−/− mice show a significantly increased concentration-dependent bronchoconstriction to intravenously administered Ach, as shown by …

Hawaiian Freshwater Polychaeta: A Potentially Substantial Trophic Component Of Stream Depositional Habitats, M. Eric Benbow, Albert J. Burky, Carl M. Way

Biology Faculty Publications

In this paper we report the widespread occurrence of large annelids (Polychaeta: Nereididae) in Hawaiian stream depositional habitats, drawing attention to the lack of knowledge of Hawaiian stream energetics. Specimens of Namalycastis sp. were collected from five Hawaiian Islands from May–July 1995 and from the island of Maui from July–December 1999 and April–July 2000. Most specimens collected were N. hawaiiensis, while two specimens of N. abiuma were collected from a single site on the island of Molokai. Specimens were collected from elevations ranging from 3–240 m; several collections were from sites above at least one major (> 15 m …

Municipal Wastewater Treatment Using Sequencing Batch Reactor (Sbr) Under Tropical Conditions, Maria Violetta Thomas

Student Works (2000-2009)

In this research project a Sequencing Batch Reactor (SBR) plant was tested for performance in terms of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Suspended Solids (SS), under different temporal conditions. In addition, the removal of biological nutrients, namely ammoniacal nitrogen, nitrate nitrogen and phosphorous in the form of phosphate, from the sewage, with anaerobic and aerobic operations using SBR was studied. The performance of the SBR plant was observed under two operating conditions whereby the variable studied was the total cycle time of the SBR process; i.e. 8-hour cycle mode and 6-hour cycle mode. The effluent quality …

Human Herpesvirus 8 Can Be Transmitted Through Blood In Drug Addicts, Carlos Sosa, Jorge Benetucci, Colleen Hanna, Laura Sieczkowski, Gabriel Deluchi, Ana Maria Canizal, Hamakwa Mantina, Winslow Klaskala, Marianna Baum, Charles Wood

Nebraska Center for Virology: Faculty Publications

Human Herpes virus type-8 (HHV-8) seroprevalence was studied in a population of HIV positive intravenous drug users (IVDUs) from Argentina. Analysis of this population also indirectly made it possible to study HHV-8 blood transmission, because these individuals frequently engage in needle sharing behavior and are capable of acquiring a broad array of blood borne pathogens, including Hepatitis B/C virus. The seroprevalence of HHV-8 in IVDUs was compared to a group of non-IVDUs and HIV negative individuals. Of the 223 individuals tested, 13.45% were HHV-8 positive, 16.99% in the IVDUs group, and 5.71% in the non-IVDUs. Among HIV positive IVDUs, 25/144 …

Interferon Regulatory Factor 7 Mediates Activation Of Tap-2 By Epstein-Barr Virus Latent Membrane Protein 1, Luwen Zhang, Joseph S. Pagano

Nebraska Center for Virology: Faculty Publications

Transporter associated with antigen processing 2 (Tap-2) is responsible for ATP-dependent transport of peptides from the cytosol to the endoplasmic reticulum, where peptides bind to newly synthesized human leukocyte antigen (HLA) class I molecules, which are essential for cellular immune responses. Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) has been shown to induce the expression of Tap-2. In this study, the induction of endogenous Tap-2 by LMP-1 is shown to be associated with and requires the expression of interferon regulatory factor 7 (IRF-7). In DG75 Burkitt’s lymphoma (BL) cells, in which LMP-1 induces the expression of IRF-7, LMP-1 induced …

Giant Vacuoles Observed In Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia

Papers in Microbiology

Large intracellular vacuoles, >4 μm in diameter and either round or oval-shaped, were observed infrequently in Dictyostelium discoideum amoebae of axenically-grown strain AX2 (only 1 in 10⁶–10⁸ cells). These previously unreported single or multiple “giant” vacuoles were more common, however, in newly germinated KAX3 cells (0.55% of the population) and AT-K_neg, a strain that lacks an esterase (0.47% of the population). A vacuolar H⁺-ATPase was enriched in their membranes of intracellular giant vacuoles, indicating that the vacuoles were related possibly to both endosomes and the contractile vacuole compartment. When monitored over time, giant …

Related Enzymatic Activities In Solid-Substrate Fermentation Of Sago Hampas With Pycnoporus Sanguineus, Rifat Ara Matta

Student Works (2000-2009)

Solid substrate fermentation (SSF) of sago pith residue known as 'hampas' with Pycnoporus sanguineus for enzyme production was carried out. Good growth of Pycnoporus sanguineus in SSF was noted on 'hampas' supplemented with 0.38% urea, 0.2% KH₂PO₄ and 0.05% MgSO₄·7H₂O over a period of 30 days. Xylanase, lignin peroxidase and laccase activities were detected in Pycnoporus sanguineus cultures. Maximum xylanase and laccase activities of 5.26U/g of substrate on day 10 of SSF and 14.35U/g on day 15 of SSF of substrate were obtained respectively. The lignin peroxidase activity was less pronounced with an activity of 1.31 U/g of substrate on …

Isolation, Screening And Characterisation Of Lactic Acid Bacteria Isolated From Local Food Sources, Ahmad Faris Mohd. Adnan

Student Works (2000-2009)

126 bacterial isolates were isolated from several local food sources. Out of these, 55 isolates were subsequently identified as lactic acid bacteria i.e. they were gram-positive and catalase negative. These 55 isolates were put through gel plug test to distinguish between homofermentative and heterofermentative isolates. 16 of the 55 lactic acid bacteria isolates were found to be homofermentative. From the 16 homofermentative isolates, seven were chosen on the basis of origin and sugars used in the enrichment process for preliminary physiological characterisation. Several conditions were chosen such as variable temperature, lactic acid tolerance, NaCl concentration and initial pH These serve …

Short-Term Temporal And Spatial Dynamics Of Bacterioplankton Near Barbados In The Caribbean Sea, Keun-Hyung Choi, Fred C. Dobbs, Robert K. Cowen

OES Faculty Publications

To investigate temporal (ca 1 mo) and spatial dynamics of bacterioplankton in the Caribbean Sea, time-series measurements of chlorophyll a concentration, bacterial abundance, and thymidine incorporation rate were performed at 6 stations near Barbados, In addition, a series of incubation experiments was carried out with seawater samples collected from various depths and stations to determine bacterial growth rates and removal rates by bacterivory. Vertically integrated phytoplankton and bacterioplankton biomasses averaged 1290 and 1200 mg C m(-2), respectively, and heterotrophic bacterial production was 106 mg C m(-2), with in situ bacterial growth of 0.1 d(-1), Approximately halfway through the sampling period, …

Characterization Of The Human Cytomegalovirus Ul75 Late Gene Promoter, Bernard J. P. Mcwatters

Theses and Dissertations in Biomedical Sciences

Gene expression during productive infection by the human cytomegalovirus (HCMV) occurs in an ordered and sequential manner, beginning with immediate early (IE), then early (E) and finally late (L) gene expression. Significant work has addressed the regulation of IE and E gene expression while relatively little work has addressed the control of late gene expression. In order to further address HCMV late gene expression, the promoter of the HCMV UL75 (glycoprotein H, gH) late gene was characterized. The data obtained in this study were combined with observations made in two other studies that have addressed HCMV late gene expression to …