Microbiology Commons^™

Impacts Of Climate Change On Soil Microorganisms In Northern Hardwood Forests, Carley Jane Kratz

Dissertations, Master's Theses and Master's Reports - Open

As global climate continues to change, it becomes more important to understand possible feedbacks from soils to the climate system. This dissertation focuses on soil microbial community responses to climate change factors in northern hardwood forests. Two soil warming experiments at Harvard Forest in Massachusetts, and a climate change manipulation experiment with both elevated temperature and increased moisture inputs in Michigan were sampled. The hyphal in-growth bag method was to understand how soil fungal biomass and respiration respond to climate change factors. Our results from phospholipid fatty acid (PLFA) analyses suggest that the hyphal in-growth bag method allows relatively pure …

The Unseen World: Environmental Microbial Sequencing And Identification Methods For Ecologists, Naupaka B. Zimmerman, J. Izard, C. Klatt, J. Zhou, E. Aronson

Biology Faculty Publications

Microorganisms inhabit almost every environment, comprise the majority of diversity on Earth, are important in biogeochemical cycling, and may be vital to ecosystem responses to large-scale climatic change. In recent years, ecologists have begun to use rapidly advancing molecular techniques to address questions about microbial diversity, biogeography, and responses to environmental change. Studies of microbes in the environment generally focus on three broad objectives: determining which organisms are present, what their functional capabilities are, and which are active at any given time. However, comprehending the range of methodologies currently in use can be daunting. To provide an overview of environmental …

High Prevalence Of Early Childhood Infection By Kshv In A Minority Population In China, Yifei Cao, Veenu Minhas, Xiaohua Tan, Jin Huang, Baodong Wang, Meiyi Zhu, Yuan Gao, Tingting Zhao, Lei Yang, Charles Wood

Nebraska Center for Virology: Faculty Publications

In China, KSHV seroprevalence varies considerably among different regions and ethnicities. But in Xinjiang province, located in the northwestern China, there is a very high seroprevalence of KSHV in adults of Kazak and Ughur ethnicities. However, KSHV prevalence in children and the risk factors associated with the acquisition of infection are currently not known. The aim of this study was to investigate the prevalence of KSHV infection, identify associated socio-economic or behavioral risk factors and the humoral immune response among children in this population. This is a cross-sectional study (N=178) to screen children and their caregivers from Xinjiang for total …

Humboldt Journal Of Microbiology: Volume 16, Number 1- May 2014, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

Regional Dust Storm Modeling For Health Services: The Case Of Valley Fever, William A. Sprigg, Slobodan Nickovic, John N. Galgiani, Goran Pejanovic, Slavo Petkovic, Mirjam Vujadinovic, Ana Vukovic, Milan Dacic, Scott Dibiase, Anup K. Prasad, Hesham El-Askary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

On 5 July 2011, a massive dust storm struck Phoenix, Arizona (USA), raising concerns for increased cases of valley fever (coccidioidomycosis, or, cocci). A quasi-operational experimental airborne dust forecast system predicted the event and provides model output for continuing analysis in collaboration with public health and air quality communities. An objective of this collaboration was to see if a signal in cases of valley fever in the region could be detected and traced to the storm - an American haboob. To better understand the atmospheric life cycle of cocci spores, the DREAM dust model (also herein, NMME-DREAM) was modified to …

Nitrogen Fertilization Has A Stronger Effect On Soil Nitrogen-Fixing Bacterial Communities Than Elevated Atmospheric Co2, Sean T. Berthrong, Chris M. Yeager, Laverne Gallegos-Graves, Blaire Steven, Stephanie A. Eichorst, Robert B. Jackson, Cheryl R. Kuske

Scholarship and Professional Work - LAS

Biological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how N-fixing bacteria will respond to global change factors such as increasing atmospheric CO₂ and N deposition. Using the nifH gene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO₂ conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO₂ to affect these communities in the temperate pine forest. Based on data …

Effects Of Urbanization On Sediment Microbial Communities In Lotic Ecosystems, Bradley Drury

Master's Theses

The world is becoming increasingly urbanized, with the majority of the world's population now living in urban areas. Urbanization has the potential to significantly alter lotic ecosystems and the services they provide. Benthic microbial communities are key components of lotic ecosystems due to their contributions to primary production and nutrient cycling. Two types of human inputs associated with urbanization that may impact benthic microbial communities in lotic ecosystems are the input of wastewater treatment effluent and the input of emerging contaminants, including pharmaceuticals and personal care products. This work examines the effects of treated WWTP effluent on benthic microbial communities …

Key Roles Of Sub-Cellular Membranes And Co-Chaperone In Tombusvirus Replication, Kai Xu

Theses and Dissertations--Plant Pathology

Positive strand RNA viruses, inculding tombusviruses, are known to utilize cellular membranes to assemble their replicase complexes (VRCs). Two tombusviruses , Tomato bushy stunt virus (TBSV) and Carnation Italian ringspot virus (CIRV), replicate on different organellar membranes, peroxisomes or endoplasmic reticulum (ER) for TBSV and mitochodria outer membranes in case of CIRV. I showed that both TBSV and CIRV replicase proteins could assemble VRCs and replicate viral RNA on purified microsomes (ER) and mitochondria. Different efficiencies of assembly was shown determined by multiple domains on TBSV or CIRV replication proteins.

To study why VRC assembly could occur on an alternative …

Nuclear Import And Interactions Of Potato Yellow Dwarf Virus Nucleocapsid, Matrix, And Phosphoprotein, Gavin Lloyd Franklin Anderson

Theses and Dissertations--Plant Pathology

Potato yellow dwarf virus (PYDV) is the type species of the genus Nucleorhabdovirus and, like all members of this genus, replication and morphogenesis occurs inside the nuclei of infected cells. Protein localization prediction algorithms failed to identify a nuclear localization signal (NLS) in PYDV nucleocapsid (N) protein, although PYDV-N has been shown to localize exclusively to the nucleus when expressed as a green fluorescent protein (GFP):N fusion in plant cells. Deletion analysis and alanine-scanning mutagenesis identified two amino acid motifs, ⁴¹⁹QKR⁴²¹ and ⁴³²KR⁴³³, that were shown to be essential for nuclear import and interaction with …

Rna Sequence Determinants Of A Coupled Termination-Reinitiation Strategy For Translation Of Downstream Orf In Helminthosporium Victoriae Virus 190s And Other Victoriviruses (Family Totiviridae), Hua Li

Theses and Dissertations--Plant Pathology

Double-stranded RNA fungal virus Helminthosporium victoriae virus 190S (genus Victorivirus, family Totiviridae) contains two large open reading frames (ORFs) that overlap in the tetranucleotide AUGA. Translation of the downstream ORF, which encodes the RNA-dependent RNA polymerase (RdRp), was previously proposed to depend on ribosomal reinitiation following termination of the upstream ORF, which encodes the capsid protein. In this study, I provided evidence to confirm that coupled termination-reinitiation (stop-restart) is indeed used. A dual-fluorescence method was established to define the RNA sequence determinants for RdRp translation. Stop-restart depends on a 32-nt stretch of RNA sequence immediately upstream of the …

Ether Bridge Formation And Chemical Diversification In Loline Alkaloid Biosynthesis, Juan Pan

Theses and Dissertations--Plant Pathology

Loline alkaloids, found in many grass-Epichloë symbiota, are toxic or feeding deterrent to invertebrates. The loline alkaloids all share a saturated pyrrolizidine ring with a 1-amine group and an ether bridge linking C2 and C7. The steps in biosynthesis of loline alkaloids are catalyzed by enzymes encoded by a gene cluster, designated LOL, in the Epichloë genome. This dissertation addresses the enzymatic, genetic and evolutionary basis for diversification of these alkaloids, focusing on ether bridge formation and the subsequent modifications of the 1-amine to form different loline alkaloids.

Through gene complementation of a natural lolO mutant and comparison …

Mechanisms For Bicarbonate-Mediated Virulence In Vibrio Cholerae, Joshua James Thomson

Wayne State University Dissertations

Vibrio cholerae is the etiologic agent of the severe diarrheal disease cholera. The aquatic bacterium is ingested by humans through contaminated water or food. Disease initiation depends on the production of the major virulence factors: cholera toxin (CT) and the toxin co-regulated pilus (TCP). The bacterium responds to signals in the human host that activate a virulence regulatory cascade termed the "ToxR Regulon". The ToxR regulon consists of various transcription regulators whose activity culminates in the production of the major virulence regulator, ToxT. ToxT directly activates transcription of CT and TCP, as well as many other gene products involved in …

Global Analysis Of Chlorella Variabilis Nc64a Mrna Profiles During The Early Phase Of Paramecium Bursaria Chlorella Virus-1 Infection, Janet M. Rowe, Adrien Jeanniard, James R. Gurnon, Yuannan Xia, David D. Dunigan, James L. Van Etten, Guillaume Blanc

Nebraska Center for Virology: Faculty Publications

The PBCV-1/Chlorella variabilis NC64A system is a model for studies on interactions between viruses and algae. Here we present the first global analyses of algal host transcripts during the early stages of infection, prior to virus replication. During the course of the experiment stretching over 1 hour, about a third of the host genes displayed significant changes in normalized mRNA abundance that either increased or decreased compared to uninfected levels. The population of genes with significant transcriptional changes gradually increased until stabilizing at 40 minutes post infection. Functional categories including cytoplasmic ribosomal proteins, jasmonic acid biosynthesis and anaphase promoting …

Dynamic Attachment Of Chlorovirus Pbcv-1 To Chlorella Variabilis, Irina Agarkova, Brigitte Hertel, Xinzheng Zhang, Les Lane, Alexander Tchourbanov, David D. Dunigan, Gerhard Thiel, Michael G. Rossmann, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

Chloroviruses infect their hosts by specifically binding to and degrading the cell wall of their algal hosts at the site of attachment, using an intrinsic digesting enzyme(s). Chlorovirus PBCV-1 stored as a lysate survived longer than virus alone, suggesting virus attachment to cellular debris may be reversible. Ghost cells (algal cells extracted with methanol) were used as a model to study reversibility of PBCV-1 attachment because ghost cells are as susceptible to attachment and wall digestion as are live cells. Reversibility of attachment to ghost cells was examined by releasing attached virions with a cell wall degrading enzyme extract. The …

Genetic Variation And Possible Mechanisms Driving The Evolution Of Worldwide Fig Mosaic Virus Isolates, Jeewan Jyot Walia, Anouk Willemsen, Eminur Elci, Kadriye Caglayan, Bryce W. Falk, Luis Rubio

Nebraska Center for Virology: Faculty Publications

Fig mosaic virus (FMV) is a multipartite negative-sense RNA virus infecting fig trees worldwide. FMV is transmitted by vegetative propagation and grafting of plant materials, and by the eriophyid mite Aceria ficus. In this work, the genetic variation and evolutionary mechanisms shaping FMV populations were characterized. Nucleotide sequences from four genomic regions (each within the genomic RNAs 1, 2, 3, and 4) from FMV isolates from different countries were determined and analyzed. FMV genetic variation was low, as is seen for many other plant viruses. Phylogenetic analysis showed some geographically distant FMV isolates which clustered together, suggesting long-distance migration. …

Risk Factors For Early Childhood Infection Of Human Herpesvirus-8 In Zambian Children: The Role Of Early Childhood Feeding Practices, Kay L. Crabtree, Janet M. Wojcicki, Veenu Minhas, David R. Smith, Chipepo Kankasa, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background—Human herpesvirus-8 (HHV-8) infection in early childhood is common throughout sub-Saharan Africa with prevalence increasing throughout childhood. Specific routes of transmission have not been clearly delineated, though HHV-8 is present in high concentrations in saliva.

Methods—To understand the horizontal transmission of HHV-8 within households to children we enrolled for cross-sectional analysis, 251 households including 254 children, age two and under, in Lusaka, Zambia. For all children, plasma was screened for HHV-8 and HIV-1 and health and behavioral questionnaires were completed. Multi-level logistic regression analysis was conducted to assess independent factors for HHV-8 infection in children.

Results—Risk factors for HHV-8 infection …

Turnip Crinkle Virus Coat Protein Inhibits The Basal Immune Response To Virus Invasion In Arabidopsis By Binding To The Nac Transcription Factor Tip, Teresa Donze, Feng Qu, Paul Twigg, T. Jack Morris

Nebraska Center for Virology: Faculty Publications

Turnip crinkle virus (TCV) has been shown to interact with a NAC transcription factor, TIP, of Arabidopsis thaliana, via its coat protein (CP). This interaction correlates with the resistance response manifested in TCV-resistant Arabidopsis ecotype Di-17. We report that failure of a mutated CP to interact with TIP triggered the corresponding TCV mutant (R6A) to cause more severe symptoms in the TCV-susceptible ecotype Col-0. We hypothesized that TCV regulates antiviral basal immunity through TIP-CP interaction. Consistent with this hypothesis, we found that the rate of accumulation of R6A was measurably slower than wild-type TCV over the course of an …

The Prevalence And Effect Of Wolbachia Infection On The Brown Widow Spider (Latrodectus Geometricus), Brittany Dane' Arrington

College of Graduate Studies: Theses & Dissertations

Wolbachia was recently identified in the Brown Widow Spider (Latrodectus geometricus). This symbiont has not previously been found in this genus, therefore the consequences on the host’s population dynamics are unknown. The frequency of endosymbiont infection can provide insight into the population dynamics of the host as this bacteria is known to alter host life history. In my 1^st chapter I determine the prevalence of Wolbachia pipentis infection in in the Brown Widow Spider (Latrodectus geometricus) from five locations in the Southeastern United States. Infection frequency differed significantly among sampling locations, ranging from 20% to …

Effects Of Organic And Conventional Agricultural Practices On Soil Microbial Communities And Molecular Detection Of Soil Borne Disease, Holli K. Milner

College of Graduate Studies: Theses & Dissertations

Agricultural practices affect soil microbial communities and health through the input of pesticides, herbicides, fertilizers, and cycling of crop rotation. By examining the microbial community structure, we analyzed how microbial species respond to the environment that individual farms create. Early detection of soil borne disease is essential for agricultural success. However, monitoring incidence of disease based on plant growth response to pathogenic inoculation may not reveal the amount of pathogenic DNA in soil. A comparative study of tomato production systems was conducted by analysis of soil microbial community structure from four farms in Southeast Georgia for the years 2012 and …

Detection, Identification And Characterization Of The Novel Campylobacter Species: Campylobacter Ureolyticus And Campylobacter Corcagiensis From Their Reservoirs., Monika Koziel

Theses

Campylobacter ureolyticus has been identified in a large proportion of diarrhoeal samples from patients in Ireland. However, the source of human infections has not been established and little is currently known about the potential reservoirs of C. ureolyticus in nature.

The aim of this project was to investigate a range of environmental and animal samples for the presence of this emerging pathogen using a molecular approach, to support the hypothesis of its zoonotic origin.

During the study, C. ureolyticus was detected in 30 out of 1,254 (2.4%) human diarrheic samples and isolated from 11 patients, describing, to the best of …