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Slideshow

The epitope specificity and function of CD8+ T cells targeting the large gene family proteins of Trypanosoma cruzi

The epitope specificity and function of CD8+ T cells targeting the large gene family proteins of Trypanosoma cruzi

Room H203, Center for Veterinary Medicine
Special Information:
Seminar also available via Zoom, see department email for link
Type of Event:
Student Seminars
Molly Bunkofske
Tarleton Laboratory
UGA Department of Microbiology

Dissertation Defense Seminar by Molly Bunkofske, Tarleton Lab

“A pain in the butt: Understanding the microaerobic physiology of Campylobacter jejuni”

Professor Dave Kelly

“A pain in the butt: Understanding the microaerobic physiology of Campylobacter jejuni” 

Online Via Zoom
Special Information:
See department email for meeting information
Type of Event:
Department Seminars
Professor Dave Kelly
School of Biosciences
The University of Sheffield, Sheffield, UK

Dahlstrom

The Dahlstrom lab is interested in how microbes choose their neighbors.  There is a competition among microbes to control the composition of a microbial community through the production of natural antimicrobial molecules, and the species composition of these communities determines the impact they have on humans, plants, and the habitability of the Earth. 

Little is known about why some bacteria and fungi are included in a given community, and others are excluded.  Additionally, as the Earth’s climate shifts, so do its soils.  Many soils are becoming more arid and permeable to oxygen, which in turn increases the toxicity of prominent antimicrobial molecules present during the development of microbial communities.  This is causing rapid changes to the environmental and rhizosphere microbial communities that humans depend on, making it imperative to understand how beneficial communities are built before they are altered. 

In particular, many fungi that are critical to plant health and ecosystem stability are often found in microbial communities despite the presence of powerful anti-fungal molecules.  Hypothesizing some bacteria may be able to promote the presence of specific fungi within the rhizosphere community, our lab co-isolated a physically associated bacterium-fungus pair belonging to genuses known to promote plant growth.  Critically, the bacterium acts as a toxin sponge, allowing the fungus to grow in the face of antimicrobial compounds.  We named the bacterium Paraburkholderia edwinii, derived from Edwin, meaning “prosperous friend”.

Using forward and reverse genetics, molecular biology, and biochemistry, we now focus on understanding the physiology of such interacting partners, including how they pair together, respond to stress, activate the bacterial protection program, and how antimicrobial molecules move through such communities.  Understanding the building blocks of microbial communities and the rules of their assembly is a critical step if we are to ultimately adapt to a warmer world.

Kurt M. Dahlstrom

Assistant Professor

The Dahlstrom lab is interested in how microbes choose their neighbors.  There is a competition among microbes to control the composition of a microbial community through the production of natural antimicrobial molecules, and the species composition of these communities determines the impact they have on humans, plants, and the habitability of the Earth. 

Little is known about why some bacteria and fungi are included in a given community, and others are excluded.  Additionally, as the Earth’s climate shifts, so do its soils.  Many soils are becoming more arid and permeable to oxygen, which in turn increases the toxicity of prominent antimicrobial molecules present during the development of microbial communities.  This is causing rapid changes to the environmental and rhizosphere microbial communities that humans depend on, making it imperative to understand how beneficial communities are built before they are altered. 

In particular, many fungi that are critical to plant health and ecosystem stability are often found in microbial communities despite the presence of powerful anti-fungal molecules.  Hypothesizing some bacteria may be able to promote the presence of specific fungi within the rhizosphere community, our lab co-isolated a physically associated bacterium-fungus pair belonging to genuses known to promote plant growth.  Critically, the bacterium acts as a toxin sponge, allowing the fungus to grow in the face of antimicrobial compounds.  We named the bacterium Paraburkholderia edwinii, derived from Edwin, meaning “prosperous friend”.

Using forward and reverse genetics, molecular biology, and biochemistry, we now focus on understanding the physiology of such interacting partners, including how they pair together, respond to stress, activate the bacterial protection program, and how antimicrobial molecules move through such communities.  Understanding the building blocks of microbial communities and the rules of their assembly is a critical step if we are to ultimately adapt to a warmer world.

Labs (via personnel):
Labs:

Ran Shi

Graduate Student
Research Interests:

Mitochondria, like nuclei, cannot be generated de novo and must be inherited. While offspring inherit nuclei from both parents, in most eukaryotes, progeny inherit mitochondria DNA (mtDNA) from the maternal side. The term uniparental inheritance (UPI) is used to describe this phenomenon. In anisogamous species, the biased contribution of mitochondria from two gametes to the zygote and subsequent passive dilution of mtDNA largely explain UPI. For example, in mammals, an oocyte contains 1000 times more copies of mtDNA than a sperm. Additional mechanisms further ensure strict UPI and prevent mtDNA heteroplasmy. Mitochondria UPI (mtUPI) is prevalent in fungi despite the fact that both gametes are of a similar cell size. As isogamy is likely the ancestral state and mtUPI might have existed in the last common eukaryotic ancestor before the divergence of animals, plants, and fungi, studying mtUPI in isogamic species will provide useful insight into the evolution of mtUPI in eukaryotic lineages. Unfortunately, meiotic progeny of the two model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, can inherit mtDNA from either parent, rendering them unsuitable for studying mtUPI. Here we propose to study mtUPI in Cryptococcus neoformans. This fungus has two mating types, α and a (no mating type switch), equivalent to males and females in mammals. C. neoformans mtUPI was discovered in 2000, and the vast majority of progeny only inherit mtDNA from the a parent. During bisexual mating, an α cell conjugates with an a cell and forms a dumbbell-shaped zygote without nuclear fusion. The two parental nuclei in the zygote duplicate and migrate in congress into the hypha that extends from the zygote. The aerial hyphal tip develops into a basidium head where the two nuclei fuse and meiosis occurs. Studies have shown that UPI is established early in the process of bisexual mating, likely soon after zygote formation. However, how mt-UPI is accomplished in Cryptococcus remains largely unknown. Several hypotheses could explain the mechanism underlying this phenomenon: (1) α mitochondria are excluded from entering the zygote or the resulting dikaryotic hyphae due to an uneven mix of organelles. (2) Alternatively, α mitochondria or its mtDNA is selectively degraded, or (3) a combination of both contributes to strict UPI. My goal is to test these hypotheses and figure out the cellular and molecular mechanism underlying mitochondria uniparental inheritance during sexual reproduction in C. neoformans

Labs (via personnel):
Selected Publications:

Shi, Ran, and Xiaorong Lin. "Illuminating the Cryptococcus neoformans species complex: unveiling intracellular structures with fluorescent-protein-based markers." Genetics (2024): iyae059.

 

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