Microbiology Commons^™

Hormones In The Field: Evolutionary Endocrinology Of Juvenile Hormone And Ecdysteroids In Field Populations Of The Wing-Dimorphic Cricket Gryllus Firmus, Anthony J. Zera, Zangwu Zhao, Katherine Kaliseck

Anthony Zera Publications

Virtually no published information exists on insect endocrine traits in natural populations, which limits our understanding of endocrine microevolution. We characterized the hemolymph titers of juvenile hormone (JH) and ecdysteroids (ECDs), two key insect hormones, in field-collected short-winged, flightless (SW) and long-winged, flight-capable (LW(f)) morphs of the cricket Gryllus firmus. The JH titer exhibited a dramatic circadian rhythm in the LW(f) morph but was temporally constant in the flightless SW morph. This pattern was consistent in each of three years; in young, middle-aged, and older G. firmus; and in three other cricket species. The ECD titer was considerably …

Environmental Controls On The Landscape-Scale Biogeography Of Stream Bacterial Communities, Noah Fierer, Jennifer L. Morse, Sean T. Berthrong, Emily S. Bernhardt, Robert B. Jackson

Environmental Science and Management Faculty Publications and Presentations

We determined the biogeographical distributions of stream bacteria and the biogeochemical factors that best explained heterogeneity for 23 locations within the Hubbard Brook watershed, a 3000-ha forested watershed in New Hampshire, USA. Our goal was to assess the factor, or set of factors, responsible for generating the biogeographical patterns exhibited by microorganisms at the landscape scale. We used DNA fingerprinting to characterize bacteria inhabiting fine benthic organic matter (FBOM) because of their important influence on stream nutrient dynamics. Across the watershed, streams of similar pH had similar FBOM bacterial communities. Streamwater pH was the single variable most strongly correlated with …

The Effect Of Residue C:N Ratio On The Turnover Of N And C In Various Soil Organic Matter Fractions, Ana B. Wingeyer

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Identifying soil organic matter (SOM) fractions that contribute to soil indigenous nitrogen (N) supply and understanding their turnover under different management constitute necessary tools toward an efficient N use. The objectives of this study were: i) trace the endpoint of carbon (C) flux from residue inputs into SOM; and ii) asses the role of the light fraction (LF), mobile humic acid (MHA) fraction and calcium humate (CaHA) fraction as N sources for heterotrophic decomposition of fresh plant residues with contrasting C:N ratio. A long-term aerobic soil incubation was carried out on ¹⁵N-labeled soil samples from Lincoln and Mead, NE. …

Differential Resource Allocation In Deer Mice Exposed To Sin Nombre Virus, Eric Wilson, Erin M. Lehmer, Christine A. Clay, Stephen St. Jeor, Denise M. Dearing

Faculty Publications

The resource allocation hypothesis predicts that reproductive activity suppresses immunocompetence; however, this has never been tested in an endemic disease system with free-ranging mammals. We tested the resource allocation hypothesis in wild deer mice (Peromyscus maniculatus) with natural exposure to Sin Nombre Virus (SNV). Immunocompetence was estimated from the extent of swelling elicited after deer mice were injected with phytohemagglutinin (PHA); swelling is positively correlated with immunocompetence. After livetrapping deer mice, we determined their reproductive state and SNV infection status. Males were more likely to be seropositive for SNV than females (37% vs. 25%) and exhibited 10% less swelling after …

Isolation Of An Anti-Cd20 Single Chain Variable Fragment From A Naive Human Phage-Scfv Library, Amma Bosompem

All Theses

CD20 is a non-glycosylated transmembrane protein expressed on normal B cells, malignant B cells, and plasma cells, but not their stem cell precursors. It is an ideal target for antibody therapy because it is not significantly shed or internalized, and CD20 expression is generally not lost after antibody binding. Depleted B cells can also be regenerated after antibody therapy. Rituximab, a chimeric monoclonal antibody against CD20, was the first monoclonal antibody to be approved by the FDA for lymphoma. Results from clinical trials have shown that anti-CD20 monoclonal antibodies, which can be used unchanged or as carriers for radionuclides or …

The Antibacterial Properties Of Brookite Phase Titanium Dioxide Nanoparticles Against Methicillin-Resistant Staphylococcus Aureus, Rupal Shah

All Theses

Staphylococcus aureus (S. aureus), a major human pathogen, is a common cause of infections worldwide due to its high virulence intensity. By adapting to rapidly changing and uniformly hostile environments, strains of S. aureus acquire resistance to antimicrobial agents shortly after their exposure. For example, within a year of its introduction, S. aureus developed resistance to methicillin which triggered the development of other antimicrobial treatments. In spite of the various antibiotics currently used to treat methicillin-resistant S. aureus (MRSA) infections, antimicrobial resistance is an unavoidable consequence due to the selective pressure of antibiotic exposure. Thus, other prevention modalities are warranted …

Differential Response Of Various Spore Species To Sporicidal Disinfectants, Michael David Pratt

Theses and Dissertations

In the fall of 2001, letters laced with anthrax spores were delivered to various news organizations in New York and Florida, as well as to two Senators in Washington, D.C. Over 22 anthrax infections and five deaths resulted from exposure to these spores, and decontamination of the affected buildings was both time consuming and costly. Since these attacks, interest in sporicidal disinfectants has increased greatly. Many chemical sporicidal disinfectants are available commercially, but the exposure time required to sterilize can be relatively long. In addition, some spores are simply injured or inhibited by chemical disinfectants, but not necessarily killed. Studies …

Lipid Microdomains Are Involved In Adhesion Of Entamoeba Histolytica Trophozoites To Host Extracellular Matrix Components, Kriti Mittal

All Theses

Entamoeba histolytica is a parasitic human protozoan that infects 500,000,000 people worldwide annually. In the course of the parasite's life cycle, motile trophozoites breach the colonic mucosa, invade through the epithelial layer and extracellular matrix (ECM) and occasionally disseminate through portal blood vessels to distant organs. Membrane rafts are small heterogeneous, highly dynamic, sterol- and sphingolipid- enriched domains whose functional significance entails compartmentalization of cellular processes and regulation of cellular signaling. Recent studies reveal the physiological role of membrane rafts in adhesion to host epithelium in E. histolytica. In the current study we examined the role of lipid rafts …

A Serratia Marcescens Oxyr Homolog Mediates Surface Attachment And Biofilm Formation, Robert M. Q. Shanks, Nicholas A. Stella, Eric J. Kalivoda, Megan R. Doe

Dartmouth Scholarship

OxyR is a conserved bacterial transcription factor with a regulatory role in oxidative stress response. From a genetic screen for genes that modulate biofilm formation in the opportunistic pathogen Serratia marcescens, mutations in an oxyR homolog and predicted fimbria structural genes were identified. S. marcescens oxyR mutants were severely impaired in biofilm formation, in contrast to the hyperbiofilm phenotype exhibited by oxyR mutants of Escherichia coli and Burkholderia pseudomallei. Further analysis revealed that OxyR plays a role in the primary attachment of cells to a surface. Similar to what is observed in other bacterial species, S. marcescens OxyR …

Laboratory And Field Responses Of Target And Non-Target Species To Algaecide Exposures, Bryand Duke

All Dissertations

In order for water resource managers to effectively and efficiently react to algal growths that are prohibiting use of a lake, reservoir or stream, information must be obtained on the response of the specific algae in site waters to algaecide exposures. In the absence of this information, ineffective algaecides or excessive treatments may be implemented. Research on development of an efficient algaecide assay using site specific samples could contribute to better decisions regarding algaecide applications and increase margins of safety for non-target species. Since these laboratory experiments provide predictions of responses of algae in site waters to algaecide exposures, these …

The Influence Of Early Experience On, And Inheritance Of, Cerebral Lateralization, Culum Brown, Jac Western, Victoria A. Braithwaite

Veterinary Science and Medicine Collection

Cerebral lateralization refers to the lateralized partitioning of cognitive function in either hemisphere of the brain. Using a standard detour test, we investigated lateralized behaviour in wild-caught, female poeciliid fish, Brachyraphis (=Brachyrhaphis) episcopi, from high- and low-predation areas. Wild fish were bred and their offspring reared under controlled laboratory conditions. These laboratory-reared fish were screened in the same laterality assays as their parents. We observed differences between wild-caught females and their laboratory-reared female offspring in the pattern of lateralization (tendency to use one hemisphere over the other to process information). Conversely, the strength of lateralization (consistency of hemispherical bias) was …

Exogenous Farnesol Interferes With The Normal Progression Of Cytokine Expression During Candidiasis In A Mouse Model, Dhammika H. M. L. P. Navarathna, Kenneth W. Nickerson, Gerald E. Duhamel, Thomas R. Jerrels, Thomas M. Petro

Papers in Microbiology

Candida albicans, a dimorphic fungus composed of yeast and mycelial forms, is the most common human fungal pathogen. Th1 cytokines such as interleukin-2 (IL-2), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), which are induced by macrophage IL-12, are critical to resistance against systemic candidiasis, while Th2 cytokines such as IL-4 and IL-5 are less critical. Farnesol is a quorum-sensing molecule produced by C. albicans that controls the formation of mycelia but is also a virulence factor. To determine whether farnesol enhances the virulence of C. albicans by modulating the production of Th1 and Th2 cytokines, mice were …

Microbial Nitrogen Limitation Increases Decomposition, Joseph M. Craine, Carl Morrow, Noah Fierer

Dartmouth Scholarship

With anthropogenic nutrient inputs to ecosystems increasing globally, there are long-standing, fundamental questions about the role of nutrients in the decomposition of organic matter. We tested the effects of exogenous nitrogen and phosphorus inputs on litter decomposition across a broad suite of litter and soil types. In one experiment, C mineralization was compared across a wide array of plants individually added to a single soil, while in the second, C mineralization from a single substrate was compared across 50 soils. Counter to basic stoichiometric decomposition theory, low N availability can increase litter decomposition as microbes use labile substrates to acquire …

Dissecting Biological “Dark Matter” With Single-Cell Genetic Analysis Of Rare And Uncultivated Tm7 Microbes From The Human Mouth, Yann Marcy, Cleber C. Ouverney, Elisabeth M. Bik, Tina Lösekann, Natalia Ivanova, Hector Garcia Martin, Ernest Szeto, Darren Platt, Philip Hugenholtz, David A. Relman, Stephen R. Quake

Faculty Publications, Biological Sciences

We have developed a microfluidic device that allows the isolation and genome amplification of individual microbial cells, thereby enabling organism-level genomic analysis of complex microbial ecosystems without the need for culture. This device was used to perform a directed survey of the human subgingival crevice and to isolate bacteria having rod-like morphology. Several isolated microbes had a 16S rRNA sequence that placed them in candidate phylum TM7, which has no cultivated or sequenced members. Genome amplification from individual TM7 cells allowed us to sequence and assemble >1,000 genes, providing insight into the physiology of members of this phylum. This approach …

The Distribution Of Sexually-Transmitted Human Papillomaviruses In Hiv Positive And Negative Patients In Zambia, Africa, Christopher Ngandwe, John Lowe, Paula J. Richards, Lara Hause, Charles Wood, Peter C. Angeletti

Nebraska Center for Virology: Faculty Publications

Background: Human Papillomaviruses (HPV) are double-stranded DNA viruses, considered to be the primary etiological agents in cervical intraepithelial neoplasias and cancers. Approximately 15–20 of the 40 mucosal HPVs confer a high-risk of progression of lesions to invasive cancer. In this study, we investigated the prevalence of sexually transmitted HPVs in Human Immunodeficiency Virus (HIV) positive and negative patients in Zambia, Africa. The rate of high-risk HPV genotypes worldwide varies within each country. Thus, we sought to investigate the rates of HPV infection in sub-Saharan Africa and the potential role of HIV in affecting the HPV genotype distribution.

Methods: This retrospective …

Characterization Of A Novel Nuclear Variant Of Bmp2 And Coordinate Regulation Of Col11a2 And Col27a1 By The Transcription Factor Lc-Maf, Jaime Lynn Mayo

Theses and Dissertations

ABSTRACT I CHARACTERIZATION OF A NOVEL NUCLEAR VARIANT OF BMP2

Bone morphogenetic protein 2 (Bmp2) is a signaling protein that was first detected by its ability to induce cartilage and bone formation. It has since been implicated in broad variety of developmental, patterning, and disease processes. To date, Bmp2 has only been known to function as an extracellular signaling molecule. However, we have obtained clear evidence for a nuclear form of Bmp2. This nuclear variant, nBmp2, contains a bipartite NLS that overlaps the site of proteolytic cleavage. The NLS remains intact and functional when translation of Bmp2 initiates from a …

Mammalian Cell Cytotoxicity Analysis Of Soybean Rust Fungicides, Steven L. Daniel, G. L. Hartman, E. D. Wagner, M. J. Plewa

Faculty Research & Creative Activity

The identification of soybean rust, caused by Phakopsora

pachyrhizi H. Sydow & Sydow, in the southern United

States in November 2004 (Schneider et al. 2005 ), in the

Midwest in 2006 (Hartman et al. 2007 ), and elsewhere has

increased the concerns of the impact of the pathogen on US

soybean production (Miles et al. 2007 ). The rapid spread of

P. pachyrhizi and its potential to cause severe yield losses

makes this among the most destructive foliar diseases of

soybean. Yield losses of 20%–60% were reported in Asia,

with losses of 80% reported from experimental plots in

Taiwan (Hartman …

Mammalian Cell Cytotoxicity Analysis Of Soybean Rust Fungicides, Steven Daniel, G. Hartman, E. Wagner, M. Plewa

Faculty Research & Creative Activity

No abstract provided.

Mammalian Cell Cytotoxicity Analysis Of Soybean Rust Fungicides, Steven L. Daniel, G. L. Hartman, E. D. Wagner, M. J. Plewa

Faculty Research & Creative Activity

No abstract provided.

Comparative Functional Analysis Of Aquaporins/Glyceroporins In Mammals And Anurans, Carissa M. Krane, David L. Goldstein

Biology Faculty Publications

Maintenance of fluid homeostasis is critical to establishing and maintaining normal physiology. The landmark discovery of membrane water channels (aquaporins; AQPs) ushered in a new area in osmoregulatory biology that has drawn from and contributed to diverse branches of biology, from molecular biology and genomics to systems biology and evolution, and from microbial and plant biology to animal and translational physiology. As a result, the study of AQPs provides a unique and integrated backdrop for exploring the relationships between genes and genome systems, the regulation of gene expression, and the physiologic consequences of genetic variation. The wide species distribution of …

Chloroviruses Encode A Bifunctional Dcmp-Dctp Deaminase That Produces Two Key Intermediates In Dttp Formation, Yuanzheng Zhang, Frank Maley, Gladys F. Maley, Garry Duncan, David Dunigan, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

The chlorovirus PBCV-1, like many large double-stranded DNA-containing viruses, contains several genes that encode putative proteins involved in nucleotide biosynthesis. This report describes the characterization of the PBCV-1 dCMP deaminase, which produces dUMP, a key intermediate in the synthesis of dTTP. As predicted, the recombinant protein has dCMP deaminase activity that is activated by dCTP and inhibited by dTTP. Unexpectedly, however, the viral enzyme also has dCTP deaminase activity, producing dUTP. Typically, these two reactions are catalyzed by proteins in separate enzyme classes; to our knowledge, this is the first example of a protein having both deaminase activities. Kinetic experiments …

Serotype Association And Regulation Of The Hyaluronate Lyase Gene Of Streptococcus Pyogenes, Martha Stokes

Theses and Dissertations in Biomedical Sciences

S. pyogenes expresses many virulence factors, controlled by a complex regulatory network. These include hyaluronate lyase, an enzyme that degrades hyaluronic acid, a major component of the human extracellular matrix. Paradoxically, hyaluronic acid is also the sole component of the bacterium's capsule, a primary defense against the host immune response. The hylA gene, which encodes the enzyme, has been shown to take three structural forms: a full-length gene, one containing a 3' deletion and a gene that produces a prematurely truncated protein. This work was intended to show that the structure of hylA is associated with serotype, and …

Clear Cell Carcinoma Of Ovary With Associated Mucinous Cystadenoma And Endometriosis, Zeeshan Uddin, Nausheen Yaqoob, Naila Kayani, Sheema H. Hasan

Department of Pathology and Laboratory Medicine

A 45 year old woman presented with right sided ovarian mass with multiple omental deposits and liver metastases. The right ovary was enlarged and showed a partly cystic partly solid cut surface. Histological picture showed clear cell carcinoma with areas of mucinous cystadenoma and endometriosis. Clear cell carcinoma is known to be associated with endometriosis. To the best of author's knowledge, it's association with mucinous cystadenoma has been described only once in the literature, where clear cell carcinoma was shown to be associated with mucinous cystadenoma without any evidence of endometriosis.

Bifa, A Cyclic-Di-Gmp Phosphodiesterase, Inversely Regulates Biofilm Formation And Swarming Motility By Pseudomonas Aeruginosa Pa14, Sherry L. Kuchma, Kimberly M. Brothers, Judith H. Merritt, Nicole T. Liberati, Frederick M. Ausubel, George A. O'Toole

Dartmouth Scholarship

The intracellular signaling molecule, cyclic-di-GMP (c-di-GMP), has been shown to influence bacterial behaviors, including motility and biofilm formation. We report the identification and characterization of PA4367, a gene involved in regulating surface-associated behaviors in Pseudomonas aeruginosa. The PA4367 gene encodes a protein with an EAL domain, associated with c-di-GMP phosphodiesterase activity, as well as a GGDEF domain, which is associated with a c-di-GMP-synthesizing diguanylate cyclase activity. Deletion of the PA4367 gene results in a severe defect in swarming motility and a hyperbiofilm phenotype; thus, we designate this gene bifA, for biofilm formation. We show that BifA localizes to the inner …

Detection Of Panulirus Argus Virus 1 In Caribbean Spiny Lobsters, Megan M. Montgomery-Fullerton, Roland Cooper, Kathryn M. Kauffman, Jeffrey D. Shields, Robert E. Ratzlaff

Collected Faculty Scholarship

Panulirus argus Virus 1 (PaV1) is a pathogenic virus that infects Caribbean spiny lobsters P. argus in the Florida Keys. We have developed a PCR detection assay for PaV1 for the purpose of studying the natural history of the virus and for monitoring the prevalence of infection. The detection of the virus in hemolymph and other tissues is based on the PCR amplification of a 499 bp product using specific primers designed from a cloned fragment of the PaV1 genome. The sensitivity limit for the assay was 1.2 fg of purified viral DNA. The PaV1 primers did not react with …

Epstein-Barr Virus Inhibits Kaposi’S Sarcoma-Associated Herpesvirus Lytic Replication In Primary Effusion Lymphomas, Dongsheng Xu, Jun Zhang, Tricia Coleman, Ashley Fagot, Catherine Kotalik, Lingjun Zhao, Pankaj Trivedi, Clinton J. Jones, Luwen Zhang

Nebraska Center for Virology: Faculty Publications

The majority of AIDS-associated primary effusion lymphomas (PEL) are latently infected with both Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV). PELs harboring two viruses have higher oncogenic potential, suggesting functional interactions between EBV and KSHV. The KSHV replication and transcription activator (K-RTA) is necessary and sufficient for induction of KSHV lytic replication. EBV latent membrane protein 1 (LMP-1) is essential for EBV transformation and establishment of latency in vitro. We show EBV inhibits chemically induced KSHV lytic replication, in part because of a regulatory loop in which K-RTA induces EBV LMP-1 and LMP-1 in turn inhibits K-RTA expression and …

The Transcriptional Repressor K-Rbp Modulates Rta-Mediated Transactivation And Lytic Replication Of Kaposi’S Sarcoma-Associated Herpesvirus, Zhilong Yang, Charles Wood

Nebraska Center for Virology: Faculty Publications

The replication and transcription activator (RTA) protein of Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV)/human herpesvirus 8 functions as the key regulator to induce KSHV lytic replication from latency through activation of the lytic cascade of KSHV. Elucidation of the host factors involved in RTA-mediated transcriptional activation is pivotal for understanding the transition between viral latency and lytic replication. KSHV-RTA binding protein (K-RBP) was previously isolated as a cellular RTA binding protein of unknown function. Sequence analysis showed that K-RBP contains a Kruppel-associated box (KRAB) at the N terminus and 12 adjacent zinc finger motifs. In similarity to other KRAB-containing zinc finger …

Parasites Alter Community Structure, Chelsea L. Wood, James E. Byers, Kathryn L. Cottingham, Irit Altman

Dartmouth Scholarship

Parasites often play an important role in modifying the physiology and behavior of their hosts and may, consequently, mediate the influence hosts have on other components of an ecological community. Along the northern Atlantic coast of North America, the dominant herbivorous snail Littorina littorea structures rocky intertidal communities through strong grazing pressure and is frequently parasitized by the digenean trematode Cryptocotyle lingua. We hypothesized that the effects of parasitism on host physiology would induce behavioral changes in L. littorea, which in turn would modulate L. littorea's influence on intertidal community composition. Specifically, we hypothesized that C. lingua …

Apres Le Deluge: Microbial Landscape Of New Orleans After The Hurricanes, Fred C. Dobbs

OES Faculty Publications

No abstract provided.

Crystal Structure Of The Vibrio Cholerae Quorum-Sensing Regulatory Protein Hapr, Rukman S. De Silva, Gabriela Kovacikova, Wei Lin, Ronald K. Taylor, Karen Skorupski, F. Jon Kull

Dartmouth Scholarship

Quorum sensing in Vibrio cholerae involves signaling between two-component sensor protein kinases and the response regulator LuxO to control the expression of the master regulator HapR. HapR, in turn, plays a central role in regulating a number of important processes, such as virulence gene expression and biofilm formation. We have determined the crystal structure of HapR to 2.2-Å resolution. Its structure reveals a dimeric, two-domain molecule with an all-helical structure that is strongly conserved with members of the TetR family of transcriptional regulators. The N-terminal DNA-binding domain contains a helix-turn-helix DNA-binding motif and alteration of certain residues in this domain …