Microbiology Commons^™

Draft Genome Sequence Of A Community-Associated Methicillin- Resistant Panton-Valentine Leukocidin-Positive Staphylococcus Aureus Sequence Type 30 Isolate From A Pediatric Patient With A Lung Infection In Brazil, Craig M. Stephens, Paul Jang-Yeon Cho, Veronica Afonso De Araujo, Ivete Martins Gomes, Selma Maria De Azevedo Sias, Claudete A. Araújo Cardoso, Lee W. Riley, Fábio Aguiar-Alves

Biology

The sequence of methicillin-resistant Staphylococcus aureus strain B6 (sequence type 30 [ST30], spa type t433, staphylococcal chromosomal cassette mec element [SCCmec] type IVc, Panton-Valentine leukocidin [PVL] positive), isolated from a pediatric patient with a lung infection in Niterói, Rio de Janeiro, Brazil, is described here. The draft genome sequence includes a 2.8-Mb chromosome, accompanied by a 20-kb plasmid containing blaZ and two small cryptic plasmids.

Role Of The C-Terminus Of The Catalytic Subunit Of Translesion Synthesis Polymerase Ζ (Zeta) In Uv-Induced Mutagensis, Hollie M. Siebler

Theses & Dissertations

Cellular DNA is under constant attack by endogenous and exogenous DNA damaging agents that threaten genome integrity. Unrepaired DNA lesions often stall replicative DNA polymerases and are bypassed by translesion synthesis (TLS) to prevent replication fork collapse. TLS mechanisms are lesion- and species-specific, with prominent roles of specialized DNA polymerases with relaxed active sites. After incorporation of nucleotide(s) across from the lesion, the distorted primer termini are typically extended by DNA polymerase ζ (Pol ζ). As a result, Pol ζ is responsible for most DNA damage-induced mutations. Mechanisms of sequential polymerase switches and regulation of Pol ζ access to DNA …

Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins

Biology Faculty Publications

Ecologists, particularly those engaged in biogeomorphic studies, often seek to connect data from three or more domains. Using three-block partial least squares regression, we present a procedure to quantify and define bi-variance and tri-variance of data blocks related to plant communities, their soil parameters, and topography. Bi-variance indicates the total amount of covariation between these three domains taken in pairs, whereas tri-variance refers to the common variance shared by all domains. We characterized relationships among three domains (plant communities, soil properties, topography) for a salt marsh, four coastal dunes, and two temperate forests spanning several regions in the world. We …

N-Acetylglucosamine Regulates Virulence Properties In Microbial Pathogens, Shamoon Naseem, James B. Konopka

Department of Molecular Genetics and Microbiology Faculty Publications

There is growing evidence that the sugar N-acetylglucosamine (GlcNAc) plays diverse roles in cell signaling pathways that impact the virulence properties of microbes and host cells. GlcNAc is already well known as a ubiquitous structural component at the cell surface that forms part of bacterial cell wall peptidoglycan, cell wall chitin in fungi and parasites, and extracellular matrix glycosaminoglycans of animal cells. Chitin and peptidoglycan have been previously linked to cell signaling as they can stimulate responses in plant and animal host cells [1–3]. Recent studies now indicate that GlcNAc released from these polymers can also …

Genetic Changes To A Transcriptional Silencer Element Confers Phenotypic Diversity Within And Between Drosophila Species, Winslow C. Johnson, Alison J. Ordway, Masayoshi Watada, Jonathan N. Pruitt, Thomas M. Williams, Mark Rebeiz

Biology Faculty Publications

The modification of transcriptional regulation has become increasingly appreciated as a major contributor to morphological evolution. However, the role of negative-acting control elements (e.g. silencers) in generating morphological diversity has been generally overlooked relative to positive-acting “enhancer” elements. The highly variable body coloration patterns among Drosophilid insects represents a powerful model system in which the molecular alterations that underlie phenotypic diversity can be defined. In a survey of pigment phenotypes among geographically disparate Japanese populations of Drosophila auraria, we discovered a remarkable degree of variation in male-specific abdominal coloration. In testing the expression patterns of the major pigment-producing enzymes, …

Isquest: Finding Insertion Sequences In Prokaryotic Sequence Fragment Data, Abhishek Biswas, David T. Gauthier, Desh Ranjan, Mohammad Zubair

Computer Science Faculty Publications

Motivation: Insertion sequences (ISs) are transposable elements present in most bacterial and archaeal genomes that play an important role in genomic evolution. The increasing availability of sequenced prokaryotic genomes offers the opportunity to study ISs comprehensively, but development of efficient and accurate tools is required for discovery and annotation. Additionally, prokaryotic genomes are frequently deposited as incomplete, or draft stage because of the substantial cost and effort required to finish genome assembly projects. Development of methods to identify IS directly from raw sequence reads or draft genomes are therefore desirable. Software tools such as Optimized Annotation System for Insertion Sequences …

The Effects Of Sustained, High-Velocity Exercise On Gene Expression In California Yellowtail (Seriola Lalandi), Kelli Hatter

Undergraduate Honors Theses

California Yellowtail muscle fibers have been observed to exhibit two drastically different development patterns resulting from the speeds at which they are exercised. When fish are exercised at a moderate rate their epaxial fast-twitch muscle fibers grow in diameter—hypertrophy; when they are exercised at a fast speed, more new epaxial fast-twitch muscle fibers are produced—hyperplasia. To determine the underlying reason for this difference in muscle development, my summer research project and honors thesis exercised fish at: fast, moderate, and control speeds for a sustained amount of time to determine what is happening on a cellular level to cause the observed …

Draft Genome Sequences Of Six Different Staphylococcus Epidermidis Clones, Isolated Individually From Preterm Neonates Presenting With Sepsis At Edinburgh's Royal Infirmary, Paul Walsh, M. Bekaert, J. Carroll, T. Manning, B. Kelly, A. O'Driscoll, X. Lu, C. Smith, P. Dickinson, K. Templeton, P. Ghazal, Roy D. Sleator

Department of Biological Sciences Publications

Herein, we report the draft genome sequences of six individual Staphylococcus epidermidis clones, cultivated from blood taken from different preterm neonatal sepsis patients at the Royal Infirmary, Edinburgh, Scotland, United Kingdom.

Addressing The Black Box Phenomenon Of Genome Sequencing And Assembly, Brandon Carter

Senior Honors Projects, 2010-2019

Genomics, a study of all genetic material in an organism, is a new discipline having a great impact on medicine, agriculture, and environmental phenomena. Most undergraduate faculty members were not formally trained in genomics and must retool themselves in order to stay current with these evolving technologies. Advances in sequencing technology have resulted in an explosion of “big data” that can only be managed and analyzed using digital methods. Multiple complex computer programs are required to teach students the concepts using hands-on methods. These programs are challenging to use, especially since the same faculty members lacking genomics training were not …

Evolution Of Sperm Activation In Nematodes, Qing Wei

Graduate School of Biomedical Sciences Theses and Dissertations

Three hermaphroditic species in the nematode genus Caenorhabditis - C. elegans, C. briggsae and C. tropicalis evolved independently from a male/female ancestor. Thus, the hermaphroditic reproductive system provides an ideal subject for studying the origin of new complex traits. Previous studies implied that this transition required two steps: a mutation that caused XY animals to make sperm, and a mutation that allowed XX spermatids to activate and fertilize oocytes. In this dissertation, I show how sperm activation is regulated in different hermaphroditic species.

First, I used TALENs to create genetic tools for C. briggsae and C. tropicalis. These tools were …

The Hippo Pathway Effector Yki Downregulates Wg Signaling To Promote Retinal Differentiation In The Drosophila Eye, Erika Lynn Wittkorn, Ankita Sarkar, Kristine Garcia, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

The evolutionarily conserved Hippo signaling pathway is known to regulate cell proliferation and maintain tissue homeostasis during development. We found that activation of Yorkie (Yki), the effector of the Hippo signaling pathway, causes separable effects on growth and differentiation of theDrosophila eye. We present evidence supporting a role for Yki in suppressing eye fate by downregulation of the core retinal determination genes. Other upstream regulators of the Hippo pathway mediate this effect of Yki on retinal differentiation. Here, we show that, in the developing eye, Yki can prevent retinal differentiation by blocking morphogenetic furrow (MF) progression and R8 specification. …

Phosphotransacetylase And Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase: Two Eukaryotic Partners Of Acetate Kinase, Tonya Taylor

All Dissertations

Although acetate is a predominant metabolite produced by many eukaryotic microbes, far less attention has been given to acetate metabolism in eukaryotes than in bacteria and archaea. Acetate kinase (Ack), which catalyzes the reversible phosphorylation of acetate from ATP, is a key enzyme in bacterial acetate metabolism. Ack primarily partners with phosphotransacetylase (Pta), which catalyzes the generation of acetyl phosphate from acetyl-CoA, but can also partner with xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), which produces acetyl phosphate from either xylulose 5-phosphate or fructose 6-phosphate. The Ack-Pta pathway, found primarily in bacteria, is also present in lower eukaryotes such as the green …

Characterization Of Putative Exbb And Exbd Leads To The Identification Of A Potential Tol-Pal System In Rhizobium Leguminosarum Atcc 14479, Valeria Barisic

Electronic Theses and Dissertations

Rhizobium leguminosarum is a Gram negative nitrogen-fixing soil bacterium. Due to the limited bioavailability of iron, bacteria utilize siderophores that scavenge and bind available iron. The transport of iron-siderophore complexes is achieved by the TonB-ExbB-ExbD complex. We have previously shown that a functional TonB protein is necessary for iron transport by creating ΔtonB mutants and assessing their growth and 55Fe-siderophore transport ability. We attempted to identify and characterize the roles of putative exbB and exbD genes using a similar approach. Growth curves and sequence analyses suggest putative exbB and exbD may be the tolpal-associated genes tolQ and tolR. Phenotypic and …

A Phylogenetic Analysis Of Dictyostelium Purpureum Based On Nuclear Rdna Sequences, Mahmoud Suliman

Graduate Theses and Dissertations

Dictyostelids (cellular slime molds) are eukaryotic microorganisms that have both unicellular and multicellular stages during their life cycle. In this study, a molecular phylogenetic analysis was conducted for isolates of one species (Dictyostelium purpureum) based DNA sequences of the ITS, 5.8S and SSU regions of nuclear rDNA. Moreover, a detailed morphological study was carried out using images obtained with both dissecting and compound microscopes. Mating experiments were carried out to assess macrocysts formation between each pair of isolates. The constructed molecular phylogenetic trees indicate that (1) D. purpureum isolates are more closely related to each other than to other species …

Functional Screening Of The Cronobacter Sakazakii Baa-894 Genome Reveals A Role For Prop (Esa_02131) In Carnitine Uptake, Audrey Feeney, Roy D. Sleator

Department of Biological Sciences Publications

Cronobacter sakazakii is a neonatal pathogen responsible for up to 80% of fatalities in infected infants. Low birth weight infants and neonates infected with C. sakazakii suffer necrotizing enterocolitis, bacteraemia and meningitis. The mode of transmission most often associated with infection is powdered infant formula (PIF) which, with an aw of ∼0.2, is too low to allow most microorganisms to persist. Survival of C. sakazakii in environments subject to extreme hyperosmotic stress has previously been attributed to the uptake of compatible solutes including proline and betaine. Herein, we report the construction and screening of a C. sakazakii genome bank and …

The Evolutionary Origination And Diversification Of A Dimorphic Gene Regulatory Network Through Parallel Innovations In Cis And Trans, Eric M. Camino, John C. Butts, Alison J. Ordway, Jordan E. Vellky, Mark Rebeiz, Thomas M. Williams

Biology Faculty Publications

The origination and diversification of morphological characteristics represents a key problem in understanding the evolution of development. Morphological traits result from gene regulatory networks (GRNs) that form a web of transcription factors, which regulate multiple cis-regulatory element (CRE) sequences to control the coordinated expression of differentiation genes. The formation and modification of GRNs must ultimately be understood at the level of individual regulatory linkages (i.e., transcription factor binding sites within CREs) that constitute the network. Here, we investigate how elements within a network originated and diversified to generate a broad range of abdominal pigmentation phenotypes among Sophophora fruit flies. …

Cell Type-Specific Responses To Wingless, Hedgehog And Decapentaplegic Are Essential For Patterning Early Eye-Antenna Disc In Drosophila, Jong-Hoon Won, Orkhon Tsogtbartarr, Wonseok Son, Amit Singh, Kwang-Wook Choi, Kyung-Ok Cho

Biology Faculty Publications

The Drosophila eye-antenna imaginal disc (ead) is a flattened sac of two-layered epithelia, from which most head structures are derived. Secreted morphogens like Wingless (Wg), Hedgehog (Hh), and Decapentaplegic (Dpp) are important for early patterning of ead, but the underlying mechanisms are still largely unknown. To understand how these morphogens function in the ead of early larval stages, we used wg-LacZ and dpp-Gal4 markers for the examination of wild-type and mutant eads. We found that the ead immediately after hatching was crescent-shaped with the Bolwig’s nerve at the ventral edge, suggesting that it consists of dorsal domain. In a subsequent …

Subsistence Strategies In Traditional Societies Distinguish Gut Microbiomes, Alexandra J. Obregon-Tito, Raul T. Tito, Jessica Metcalf, Krithvivasa Sankaranarayanan, Jose C. Clemente, Luke K. Ursell, Zhenjiang Zech Xu, Will Van Treuren, Rob Knight, Morris Foster

Division of Research and Economic Development Faculty & Staff Publications

Recent studies suggest that gut microbiomes of urban-industrialized societies are different from those of traditional peoples. Here we examine the relationship between lifeways and gut microbiota through taxonomic and functional potential characterization of faecal samples from hunter-gatherer and traditional agriculturalist communities in Peru and an urban-industrialized community from the US. We find that in addition to taxonomic and metabolic differences between urban and traditional lifestyles, hunter-gatherers form a distinct sub-group among traditional peoples. As observed in previous studies, we find that Treponema are characteristic of traditional gut microbiomes. Moreover, through genome reconstruction (2.2-2.5 MB, coverage depth x26-513) and functional potential …

Early Initiation Of Antiretroviral Therapy Can Functionally Control Productive Hiv-1 Infection In Humanized-Blt Mice, Qingsheng Li, For Yue Tso, Guobin Kang, Wuxun Lu, Yue Li, Wenjin Fan, Zhe Yuan, Christopher J. Destache, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background—Recent reports showed that functional control of HIV-1 infection for a prolonged time is possible by early anti-retroviral therapy (ART); however its underlying mechanism needs to be studied with a suitable animal model. Recently, humanized-BLT (bone marrow, liver and thymus) mouse (hu-BLT) was shown to be an excellent model for studying HIV-1 infection. We thus tested the feasibility of studying functional control of HIV-1 infection using hu-BLT mice.

Methods—Animals in three treatment groups (Rx-6h, Rx-24h, Rx-48h) and untreated group were infected with HIV-1, followed by ART initiation at 6, 24 or 48 hours post-infection and continued daily for two weeks. …

The Role Of Dendritic Cell Subsets And Innate Immunity In The Pathogenesis Of Type 1 Diabetes And Other Autoimmune Diseases, Jeffrey D. Price, Kristin V. Tarbell

Nebraska Center for Virology: Faculty Publications

Dendritic cells (DCs) are key antigen-presenting cells that have an important role in autoimmune pathogenesis. DCs control both steady-state T cell tolerance and activation of pathogenic responses. The balance between these two outcomes depends on several factors, including genetic susceptibility, environmental signals that stimulate varied innate responses, and which DC subset is presenting antigen. Although the specific DC phenotype can diverge depending on the tissue location and context, there are four main subsets identified in both mouse and human: conventional cDC1 and cDC2, plasmacytoid DCs, and monocyte-derived DCs. In this review, we will discuss the role of these subsets in …

A Nuclear Fraction Of Turnip Crinkle Virus Capsid Protein Is Important For Elicitation Of The Host Resistance Response, Sung-Hwan Kang, Feng Qu, Thomas J. Morris

Nebraska Center for Virology: Faculty Publications

The N-terminal 25 amino acids (AAs) of turnip crinkle virus (TCV) capsid protein (CP) are recognized by the resistance protein HRT to trigger a hypersensitive response (HR) and systemic resistance to TCV infection. This same region of TCV CP also contains a motif that interacts with the transcription factor TIP, as well as a nuclear localization signal (NLS). However, it is not yet known whether nuclear localization of TCV CP is needed for the induction of HRT-mediated HR and resistance. Here we present new evidence suggesting a tight correlation between nuclear inclusions formed by CP and the manifestation of HR. …

A Novel Codon-Optimized Siv Gag-Pol Immunogen For Genebased Vaccination, Catherine M. Crosby, Eric A. Weaver, Reeti Khare, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

Simian immunodeficiency virus (SIV) is a robust pathogen used in non-human primates to model HIV vaccines. SIV encodes a number of potential vaccine targets. By far the largest and most conserved protein target in SIV is its gag-pol protein that bears many epitopes to drive multivalent immune T cell responses. While gag-pol is an attractive antigen, it is only translated after a frame shift between gag and pol with the effect that gag and pol are expressed at an approximate 10/1 ratio. The codon bias of native lentiviral genes are also mismatched with the abundance of tRNAs in mammalian cells …

The Role Of Dksa In The Stringent Response In The Lyme Disease Spirochete Borrelia Burgdorferi, Britney Cheff

Graduate Student Theses, Dissertations, & Professional Papers

Borrelia burgdorferi, the bacterium that causes Lyme disease, is maintained in nature through an enzootic cycle that includes a tick vector and a vertebrate host. The bacterium is acquired by an Ixodes tick from an infected vertebrate. The bacterium alters its gene expression to adapt to different environments of the tick and vertebrate. Between tick feedings, B. burgdorferi must contend with nutrient stress. The stringent response is a physiological mechanism when bacteria switch from “thriving” to “surviving” mode in response to limited nutrient resources; it is mediated by an increase in the nucleotide alarmone guanosine penta- or tetraphosphate, abbreviated …

Mysteries Of The Trypanosomatid Maxicircles: Characterization Of The Maxicircle Genomes And The Evolution Of Rna Editing In The Order Kinetoplastida, Preethi Ranganathan Iyengar

Theses and Dissertations

The trypanosomatid protists belonging to Order Kinetoplastida are some of the most successful parasites ever known to mankind. Their extreme physiological diversity and adaptability to different environmental conditions and host systems make them some of the most widespread parasites, causing deadly diseases in humans and other vertebrates.

This project focuses on their unique mitochondrion, called the kinetoplast, and more specifically involves the characterization of a part of their mitochondrial DNA (also called kinetoplast DNA or kDNA), the maxicircles, which are functional homologs of eukaryotic mitochondrial DNA in the kinetoplastid protists. We have sequenced and characterized the maxicircle genomes of 20 …

Characterization Of The Interactions Between Staphylococcal Phage 80 Alpha Scaffold And Capsid Proteins, Laura Klenow

Theses and Dissertations

Staphylococcal phage 80α can serve as a helper bacteriophage for a family of mobile genetic elements called Staphylococcus aureus pathogenicity islands (SaPIs). The prototype island, SaPI1, is able to hijack the 80α capsid assembly process and redirect capsid formation to yield smaller, phage-like transducing particles carrying SaPI DNA. Capsid size redirection is accomplished through two SaPI1-encoded gene products, CpmA and an alternate scaffold protein, CpmB. The normal 80α scaffold and the SaPI1 CpmB scaffold share a small block of conserved residues at their C-termini, several of which had been shown to be essential for CpmB function. This led to the …

Whole-Genome Sequencing Of Kaposi’S Sarcoma-Associated Herpesvirus From Zambian Kaposi’S Sarcoma Biopsy Specimens Reveals Unique Viral Diversity, Landon Olp, Adrien Jeanniard, Clemence Marimo, Charles Wood

Nebraska Center for Virology: Faculty Publications

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent for Kaposi’s sarcoma (KS). Both KSHV and KS are endemic in sub-Saharan Africa where approximately 84% of global KS cases occur. Nevertheless, whole-genome sequencing of KSHV has only been completed using isolates from Western countries—where KS is not endemic. The lack of whole-genome KSHV sequence data from the most clinically important geographical region, sub-Saharan Africa, represents an important gap since it remains unclear whether genomic diversity has a role on KSHV pathogenesis. We hypothesized that distinct KSHV genotypes might be present in sub-Saharan Africa compared to Western countries. Using a KSHV-targeted enrichment …

Observed And Expected Incidence Of Cervical Cancer In Lusaka And The Southern And Western Provinces Of Zambia, 2007 - 2012, Mulele Kalima, Kennedy Lishimpi, Jane L. Meza, Shinobu Watanabe-Galloway, Susan C. Msadabwe, Catherine K. Mwaba, Aaron L. Shibemba, Lewis Banda, Charles Wood, Robert M. Chamberlain, Amr S. Soliman

Nebraska Center for Virology: Faculty Publications

Objectives—Cervical cancer is increasing but underestimated in developing countries. We calculated the observed and expected incidence of cervical cancer in Lusaka and Southern and Western provinces of Zambia.

Methods/Materials—Data for 2007-2012 was obtained for the 3 provinces. Data included age, residence, year of diagnosis, marital status, occupation, HIV, stage, radiotherapy and chemotherapy. Expected incidence in Southern and Western provinces was calculated based on observed incidence for Lusaka province, adjusting for HIV.

Results—Crude and age-standardized incidence rates (ASR) in Lusaka were 2-4 times higher than incidence in the other 2 provinces. Lusaka had a rate of 54.1/10⁵ and ASR of …

Crf07_Bc Strain Dominates The Hiv-1 Epidemic In Injection Drug Users In Liangshan Prefecture Of Sichuan, China, Lin Li, Daying Wei, Wan-Ling Hsu, Tianyi Li, Tao Gui, Charles Wood, Yongjian Liu, Hanping Li, Zuoyi Bao, Siyang Liu, Xiaolin Wang, Jingyun Li

Nebraska Center for Virology: Faculty Publications

The Liangshan prefecture in Sichuan province is an area in China severely affected by the HIV epidemic, with intravenous drug use (IDU) as the main risk factor. No reports on HIV subtypes prevalent in IDUs in Liangshan prefecture could be found. In this study, we have characterized the genotypes of HIV-1 in the IDU population in Liangshan prefecture and further determined the phylogenetic relationship of the CRF07_BC strains to HIV-1 sequences from the other regions of China, including Xinjiang and Yunnan provinces, to explore the pattern and possible diffusion pathway of HIV-1 in these regions. HIV-1-seropositive drug-naive IDUs identified in …

Developing Microbial Biomarkers To Non-Invasively Assess Health In Wild Elk (Cervus Canadensis) Populations, Samuel B. Pannoni

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The composition of the intestinal bacterial community (intestinal microbiome) of mammals is associated with changes in diet, stress, disease and physical condition of the animal. The relationship between health and the microbiome has been extensively demonstrated in studies of humans and mice; this provides strong support for its potential utility in wildlife. When managing elk (Cervus canadensis), federal and state agencies currently must rely on invasive sampling and coarse demographic data on which to base their decisions. By developing microbiome-based biomarkers that vary as a function of elk body condition and disease (i.e. microbial biomarkers), we hope to …

Metagenomics For Bacteriology, Erika Del Castillo, Jacques Izard

Department of Food Science and Technology: Faculty Publications

The study of bacteria, or bacteriology, has gone through transformative waves since its inception in the 1600s. It all started by the visualization of bacteria using light microscopy by Antonie van Leeuwenhoek, when he first described “animalcules.” Direct cellular observation then evolved into utilizing different wavelengths on novel platforms such as electron, fluorescence, and even near-infrared microscopy. Understanding the link between microbes and disease (pathogenicity) began with the ability to isolate and cultivate organisms through aseptic methodologies starting in the 1700s. These techniques became more prevalent in the following centuries with the work of famous scientists such as Louis Pasteur …