2013 - Spring Semester Speaker Schedule

Thursday, Jan. 31

11:20 AM

DSB 130

Aquatic Microbial Hotspots: Biogeochemistry, Ecology and Pathogenesis

Richard Long

Biological Sciences Dept., Univ. of South Carolina

The upper ocean is "the lung of the ocean."  It draws in CO2 and through vertical advection and the "biological carbon pump" transfers carbon to other environmental "organs", i.e. the mesopelagic, deep ocean and seafloor. Marine snow is a major constituent of the C-pump; these organic aggregates are heavily colonized and serve as hot spots for microbial activity.  The marine snow associated bacterial communities mediate the selective degradation of organic matter on these sinking particles and compete for resources.  I will test the hypothesis that chemically mediated antagonism is a common phenotype for bacteria isolated from these systems and will discuss the potential consequences that these interactions may have for species dynamics on marine snow, including the waterborne human pathogen Vibrio cholerae. Lastly, I will shift to aquatic reservoirs that may enhance the virulence of V. cholerae through elicitation of the Acid Stress Reponses. This subsystem facilitates V. cholerae survival as it pass through the lower stomach and subsequent colonization of the small intestine.

 

Tuesday, Feb. 5

11:20 AM

DSB 130

Virulence Evolution and Gender Susceptibility in Cryptococcus neoformans

Erin McClelland

Currently adjuct in MTSU Biology Dept. and consultant for Berg Pharma, Nashville

Formerly at Commonwealth Medical College, Scranton, PA

I will present a brief background on the pathogenic yeast Cryptococcus neoformans and why we study it.  I will discuss the use of serial passage experiments to study the evolution of virulence and then describe the results of two different serial passage experiments. I will also discuss a project we are working on to identify genes that are involved in virulence using a C. elegans reduced pathogenicity screen. Finally, I will discuss how host gender affects the pathogenesis of C. neoformans infections.

 

Thursday, Feb. 7

11:20 AM

DSB 130

Clocks, Oscillators and Aging

David Nelson

Dept. of Pathology, University of Cambridge

Life on our planet has been shaped by the regular, rhythmic changes of the environment. The daily cycles of light and dark have necessitated the evolution of internal oscillators, like the circadian clock, to coordinate timely physiological and behavioral adaptations to environmental change. At the molecular level, these systems are constructed of genes operating in feedback loops, producing oscillating cycles of protein expression and degradation in time with the external changes to which they are entrained.

However, it is becoming increasingly clear that oscillations are not exclusive to biological clocks and can be used to do more than mirror external change. In the first part of my talk, I will describe how the "master regulator" of the inflammatory response, the NF-κB pathway, encodes complex biological information in the form of transcription factor oscillations to control gene expression programs. I will also show how mathematical modeling can be used to help us understand and manipulate the behavior of this pathway in vivo. In the second part of my talk, I will focus on a small network of genes that are known to regulate the NF-κB pathway that also participate in a process called mitophagy, the removal of damaged mitochondria from the cell. I will discuss how errors in this process caused by heritable, germline mutations can lead to the early acquisition of one of the most common neurodegenerative disease of aging, Parkinson's disease.

 

Tuesday, Feb. 12

11:20 AM

DSB 130

Small Regulatory RNA Form and Function

Alex Flynt

Dept. of Developmental Biology, Sloan Kettering Institute, NY

A surprising development in the post-genome era is that animal genomes contain a large fraction of transcripts that appear to have no potential to code for proteins. This has challenged the central dogma and revised the definition of what constitutes a gene. Functional studies have revealed a variety of biological activities for non-coding RNAs that range from roles as structural elements, to modulators of physiology, to determinants of cell-fate. Furthermore, non-coding regions of genomes are typically poorly conserved suggesting these genes may be an important source of genetic novelty–driving morphological and behavioral innovation. My research is focused on several classes small non-coding RNAs, which includes microRNAs and small-interfering RNAs. Using computational analysis of genome-wide small RNA expression datasets, combined with biochemical and genetic studies I have identified new varieties of these molecules and unexpected biogenesis pathways. Going forward my research aims to identify new non-coding RNA species, and investigate the role of RNA metabolism in animal development.

 

Thursday, Feb. 14

11:20 AM

DSB 130

Aquatic Microbial Hotspots: Biogeochemistry, Ecology and Pathogenesis

Richard Long

Biological Sciences Dept., Univ. of South Carolina

The upper ocean is "the lung of the ocean." It draws in CO2 and through vertical advection and the "biological carbon pump" transfers carbon to other environmental "organs", i.e. the mesopelagic, deep ocean and seafloor. Marine snow is a major constituent of the C-pump; these organic aggregates are heavily colonized and serve as hot spots for microbial activity. The marine snow associated bacterial communities mediate the selective degradation of organic matter on these sinking particles and compete for resources. I will test the hypothesis that chemically mediated antagonism is a common phenotype for bacteria isolated from these systems and will discuss the potential consequences that these interactions may have for species dynamics on marine snow, including the waterborne human pathogen Vibrio cholerae. Lastly, I will shift to aquatic reservoirs that may enhance the virulence of V. cholerae through elicitation of the Acid Stress Reponses. This subsystem facilitates V. cholerae survival as it pass through the lower stomach and subsequent colonization of the small intestine.

 

Tuesday, Feb. 19

11:20 AM

DSB 130

Regulation of planar cell polarity during vertebrate morphogenesis

Jason Jessen

Department of Medicine and the Department of Cancer Biology, Vanderbilt University Medical Center

Planar cell polarity (PCP) describes the polarization of cells or cellular structures within the plane of a tissue and is an essential feature of embryonic morphogenesis. Disruption of vertebrate PCP is associated with multiple disorders including neural tube closure defects, ciliopathies, deafness, and potentially cancer. Two major questions face all fields of PCP research. First, what are the downstream effectors that transform signals from core PCP proteins into changes in cell polarity? Second, how is information communicated between cells to establish and maintain polarity in a planar tissue? Extensive characterization of PCP in the fly wing epithelium demonstrates that antagonistic interactions between Van Gogh and Frizzled/Dishevelled signaling function to polarize the formation of actin-rich hairs. By contrast, despite a decade of speculation that asymmetric expression of these core PCP proteins polarizes the formation of membrane protrusions during gastrulation cell movements, the actual molecular mechanisms remain unclear. The current theme of my research is to provide a new experimental paradigm explaining how PCP signaling coordinates the directed migration of polarized cell populations. Towards this goal, we have shown for the first time that core PCP proteins differentially impact cell-extracellular matrix interactions and cadherin-mediated cell cohesion. These exciting data suggest a novel mechanism to regulate polarized membrane protrusive activity across a field of migrating cells. Since collective migration is also considered an effective migration strategy for mesenchymal and epithelial cancers, our studies are directly relevant to the understanding of tumor invasiveness.

 

Thursday, Feb. 21

11:20 AM

DSB 130

Aquaculture Research:  Aiming to Improve Rainbow Trout Production Efficiency and Product Quality

Caird E. Rexroad III

USDA/ARS National Center for Cool and Cold Water Aquaculture (NCCCWA)

The USDA/ARS National Center for Cool and Cold Water Aquaculture (NCCCCWA) in Leetown, West Virginia has the mission of enhancing the nation's aquaculture production by developing improved germplasm and technologies that increase farm efficiency, product quality, and environmental sustainability. Our research focuses primarily on rainbow trout and encompasses genetics, genomics, physiology, aquatic animal health, and aquaculture engineering. Ultimately we envision growth in US aquaculture production that is efficient, contributes to sustainable environments, provides a healthy seafood option for consumers, and supports recreational opportunities for anglers. To begin I will present an overview of NCCCWA research projects and recent progress regarding polyploidy, selective breeding and fish health; then I will focus on efforts to identify genes affecting response to crowding stress through genetic mapping and functional genomic approaches.

 

Tuesday, Mar. 5

11:20 AM

DSB 130

Response of Bluegill to 35 Years of Thermal Extremes: A Case of Rapid Evolution?

Bud Fischer

Dean, College of Basic and Applied

Sciences, MTSU

Extreme environments, either natural or man-made, may provide an excellent opportunity to determine the selection pressures and time interval over which evolution can occur.   An environment that has been exposed to both chronic and acute thermal perturbation is the Par Pond Reservoir System located on the Savannah River Site near Aiken, South Carolina.  For most of the past 35 years nuclear production reactors on the Savannah River Site have produced cooling water that was heated to more than 50 oC and then released into the Par Pond reservoir system, which is a closed loop system of canals and reservoirs, that includes Pond C (67 ha) and Par Pond (1100 ha).   When the reactor is operational, heated effluent flows through four cooling ponds and then enters Pond C at approximately 50 oC.  At least 90 % of the water in Pond C reaches lethal limits for almost all living organisms during periods of long reactor operation.  The severe and chronic effects of the heated water on the biological community in Pond C are both extreme and for the most part unpredictable.   Thus, the chronic acute and unpredictable nature of the thermal perturbation, has allowed me to test working hypothesis in regard to changes in life history, morphology, physiology in the bluegill sunfish, Lepomis macrochirus and to determine whether these changes are the results of developmental processes and/or selection pressure.

 

Friday, Mar. 22

12:40 PM

DSB 106

Macrofungi in Endangered Tropical Ecosystems

Tim Baroni

Dept. of Biological Sciences,

State University of New York (SUNY), Cortland

After a brief presentation on fungal biology and why these organisms are important to humans and the planet we live on, the main focus of the talk will cover 10 years of NSF supported exploration of macrofungal biodiversity in tropical America. New genera, new species, undergraduate student research, tropical wildlife, stories of triumph and stories of frustration will be the topics.

 

 

Updated Seminar Schedule – 2012/13 Academic Year

All seminars are in DSB 130 at 11:20 AM unless otherwise noted

Jan. 22 – Ashley Morris, MTSU (Tenure and Promotion Seminar)

Jan. 24 – Heath Mills, Texas A&M (Microbiologist Candidate)

Jan. 29 – Laura Musselman, Washington Univ. (Cell Biologist Candidate)

Jan. 31 – Richard Long, Univ. of South Carolina (Microbiologist Candidate)

Feb. 5 – Erin McClelland, Univ. of Scranton; currently adjunct at MTSU (Microbiologist Candidate)

Feb. 7 – David Nelson, Univ. of Cambridge (Cell Biologist Candidate)

Feb. 12 – Alex Flynt, Memorial Sloan-Kettering Cancer Center (Cell Biologist Candidate)

Feb. 19 – Jason Jessen, Vanderbilt Univ. (Cell Biologist Candidate)

Feb. 21 - Caird E. Rexroad, National Center for Cool and Cold Water Aquaculture

Mar. 5 – Bud Fischer, MTSU

Mar. 22 - Tim Baroni

Apr. 9 – MOBI 7400 Students

Apr. 16 – MOBI 7400 Students

Apr. 23 – MOBI 7400 Students