Microbial Processes in Biogeochemical Cycles: Case Studies of Methanogenic Archaea and Phycosphere Bacterial Communities Tuesday, April 20 2021, 11:10am Online via Zoom Special Information: Please contact Nancy Perkins at nancydh@uga.edu for Zoom link and passcode Type of Event: Department Seminars Dr. He (Andrew) Fu Department of Marine Sciences University of Georgia Abstract: Since the inception of life on Earth ~3.8 billion years ago, microorganisms have shaped and defined Earth’s biosphere and have created conditions that allowed the existence of all higher trophic life forms, including human societies. The microbial ‘unseen majority’ drives nearly all biogeochemical cycles. However, given their immense diversity, complex interactions and varied responses to environmental changes, we still have a limited understanding on how microorganisms affect climate change (including the production and consumption of climate-active molecules) and how they in turn will be affected. In this talk, I will focus on two research topics in the context of global carbon and sulfur cycles. The first study elucidates the molecular mechanisms of how methanogenic Archaea metabolize methylated sulfur compounds. The second study concentrates on marine bacterial communities that associate with marine phytoplankton cells. These projects demonstrate the power of integrating physiological and ecological approaches to understand microorganism–climate connections, which are essential for achieving an environmentally sustainable future. Read more about Microbial Processes in Biogeochemical Cycles: Case Studies of Methanogenic Archaea and Phycosphere Bacterial Communities
2021 Summer Research Grant Recipients The Microbiology Department is happy to announce that we have THREE Summer Research Grant recipients! Congratulations to Alyssa Baugh, Michael Mills, and Amy Siceloff! Read more about 2021 Summer Research Grant Recipients
Terminal Steps of Heme Biosynthesis Friday, April 30 2021, 1pm Online via Zoom Special Information: Email mibcoord@uga.edu for more information. Type of Event: Student Seminars Sophia Weerth Dailey Laboratory UGA Dept of Microbiology Abstract or other information: Abstract (51.03 KB) Read more about Terminal Steps of Heme Biosynthesis
Bacteriophage roles in the diversity and horizontal transfer of protective functions in the heritable bacterial symbiont, Hamiltonella defensa Bacteriophage roles in the diversity and horizontal transfer of protective functions in the heritable bacterial symbiont, Hamiltonella defensa Friday, April 30 2021, 11:30am Online via Zoom Special Information: Email mibcoord@uga.edu for meeting information Type of Event: Student Seminars Nicole Lynn-Bell Oliver Laboratory UGA Dept of Microbiology Read more about Bacteriophage roles in the diversity and horizontal transfer of protective functions in the heritable bacterial symbiont, Hamiltonella defensa
OTA Award Winners Announced for 2020-2021 We would like to congratulate Michael Mills and Tao Wang on receiving the Outstanding Teaching Assistant Award for 2020-2021! The Center for Teaching and Learning administers the Outstanding Teaching Assistant (OTA) award, sponsored by the Office of the Vice President for Instruction. This award recognizes teaching assistants who demonstrate superior teaching skills while serving in the classroom or laboratory. Way to go Michael and Tao!! Read more about OTA Award Winners Announced for 2020-2021
"A World of Small Phages in the Human Gut and Beyond" Thursday, April 15 2021, 11:10am Online via Zoom Special Information: Please contact Nancy Perkins at nancydh@uga.edu for Zoom link and passcode Type of Event: Department Seminars Dr. Paul Kirchberger Department of Integrative Biology University of Texas at Austin Abstract: Single-stranded DNA phages of the family Microviridae have fundamentally different evolutionary origins and dynamics than their more frequently studied double-stranded DNA counterparts. Despite their small size (generally <5kb), which imposes extreme constraints on genomic innovation, microviruses have adapted to become prominent components of viromes in numerous ecosystems and hold a dominant position among viruses in the human gut. Yet until recently, they were known almost exclusively from metagenomic sequence data. By in-vitro synthesizing and transforming their miniature genomes into an E. coli host, I develop an experimentally tractable host-virus system that allows their study in the laboratory. Through building microviruses with combinations of genomic segments from different phages (mimicking diversity observed in natural populations), their interactions with each other and with their hosts can be recreated. Using this approach, I discover the role of a hypervariable genomic region in prophages that defends their hosts against infection by other members of the microvirus population. By detecting microviruses in metagenomic and genomic datasets, I show that this hypervariable region has evolved multiple times independently in response to the preceding evolution of lysogenic ability. These results provide a rare insight into the biology of these elusive phages and emphasize the importance of virus-virus interactions in viral evolution in general. The establishment of a microviral model system also paves the way for gaining a more thorough understanding of the roles of microviruses in the larger ecosystem of the human gut and elsewhere. Read more about "A World of Small Phages in the Human Gut and Beyond"
"Bacterial sensing, elimination, and manipulation of reactive oxygen species" Tuesday, April 13 2021, 11:10am Online via Zoom Special Information: Please contact Nancy Perkins at nancydh@uga.edu for Zoom link and passcode Type of Event: Department Seminars Dr. Arden Perkins Institute of Molecular Biology University of Oregon Abstract: The paradigm has been that reactive oxygen species are toxic to bacteria. Indeed, an important strategy by which immune cells like neutrophils control and eliminate invading microbes is through synthesizing bleach (HOCl), the same chemical used as a household disinfectant. However, bacteria that colonize animals are not passive players and have evolved their own counter strategies to manipulate and repurpose reactive oxygen species in surprising ways. My research focuses on pro-inflammatory bacteria that have acquired robust antioxidant defenses sufficient to colonize inflamed tissue and tolerate millimolar concentrations of bleach. I will discuss my discovery that some pathogenic bacteria are attracted to bleach, which is potentially a mechanism by which they seek and acquire nutrients from damaged host tissue. Read more about "Bacterial sensing, elimination, and manipulation of reactive oxygen species"
Investigating the Effects of a Cytosine Specific Methyltransferase in Gene Expression of Helicobacter pylori Investigating the Effects of a Cytosine Specific Methyltransferase in Gene Expression of Helicobacter pylori Thursday, April 8 2021, 12:30pm Online via Zoom Bowen Meng Hoover Laboratory UGA Dept of Microbiology Read more about Investigating the Effects of a Cytosine Specific Methyltransferase in Gene Expression of Helicobacter pylori
"Insights into S. aureus infection physiology through -omics approaches" Thursday, April 8 2021, 11:10am Online via Zoom Type of Event: Department Seminars Dr. Carolyn Ibberson School of Biological Sciences Georgia Institute of Technology Abstract: Chronic infections place a significant burden on healthcare systems, requiring over $20 billion in treatment annually in the United States alone. Notably, chronic infections are frequently polymicrobial and are often recalcitrant to antibiotic treatment, through a process termed “synergy”. Despite the clinical importance, many key features of bacterial physiology in chronic infections, including the molecular mechanisms and impacts of microbe-microbe interactions, remain understudied, in part due to the challenge of assessing bacterial physiology in the human host. My work aims to address this challenge, focused on the human pathogen Staphylococcus aureus, a leading cause of human infection worldwide and a significant cause of both morbidity and mortality. Specifically, I ask foundational questions about how S. aureus, causes disease and persists in human infection, both by using validated experimental models of infection and by directly analyzing human clinical samples. In my previous work, I found co-infection altered the requirement for ~6% (192 genes) of the S. aureus genome when compared to mono-infection in three different infection models, indicating global changes in S. aureus metabolism in response to another microbe, highlighting the importance of microbe-microbe interactions in mediating bacterial physiology in vivo. In addition, I recently performed the first large scale assessment of S. aureus physiology in situ in chronic human infection and found remarkable conservation of S. aureus gene expression in the cystic fibrosis (CF) lung across patients using RNA-seq, despite numerous epidemiological differences. With this data, I inferred the metabolic state and nutritional environment of S. aureus in CF sputum including iron scarcity, carbohydrate use, and virulence factor production. Further, through a machine learning framework, I defined a ‘human CF lung transcriptome signature’ – 32 genes whose transcription distinguishes human CF sputum from other in vivo and in vitro environments, primarily consisting of genes involved in metabolism and virulence – and was able to apply these findings to make an in vitro model more similar to CF infection. Ongoing work further explores mechanisms that allow S. aureus to establish and persist in chronic polymicrobial infections, including CF, osteomyelitis, and chronic wounds, centered on the role of microbe-microbe interactions. Read more about "Insights into S. aureus infection physiology through -omics approaches"
"Comprehensive glycoproteomics of prokaryotes and its importance for understanding biofilm formation" Thursday, April 1 2021, 11:10am Online via Zoom Special Information: Please contact Nancy Perkins at nancydh@uga.edu for Zoom link and passcode Type of Event: Department Seminars Dr. Stefan Schulze Department of Biology University of Pennsylvania Abstract: Protein glycosylation, one of the most complex post-translational modifications, plays central roles in a variety of cellular processes in prokaryotes. Elucidating its involvement in biofilm formation is crucial for a detailed understanding of antibiotic resistance and pathogenicity mechanisms. Yet the complexity and variability of glycoproteins in prokaryotes have made their system-wide analysis, thus far, virtually unachievable. Here, I will present an interdisciplinary approach that combines bioinformatics, comprehensive glycoproteomics and phenotypic characterizations for the functional analysis of prokaryotic glycosylation. This includes the development of universally applicable bioinformatic tools that are suitable to analyze the plethora of glycan compositions existing in prokaryotes, as well as the initiation of the Archaeal Proteome Project, a community-effort that combines proteomics datasets across a broad range of experimental conditions to harvest the wealth of information buried within them. Together with an in-depth proteomic analysis of glycosylation pathway mutants from the model archaeon Haloferax volcanii, this has led to the identification of the largest archaeal glycoproteome described so far. It also revealed the concurrence of two independent N-glycosylation pathways that can modify the same glycosylation sites. A variety of phenotypic assays of mutants defective in N-glycosylation pathways or glycosylated proteins were further used to show the involvement of glycosylation in crucial cellular processes such as biofilm formation and cell shape. The establishment of these approaches for H. volcanii not only provided new insights into the extent, complexity, and roles of glycosylation in archaea, but their applicability to a multitude of prokaryotes also paves the way for functional glycoproteomics in biofilm forming pathogens such as Pseudomonas aeruginosa. Read more about "Comprehensive glycoproteomics of prokaryotes and its importance for understanding biofilm formation"