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Microbial Biology Faculty

The Bruns Lab has two central research themes: fungal ecology and evolution, with molecular systematics crucial to both. This Lab contributed some of the first sequence-based analyses of fungal evolution and developed oligonucleotide primers to the ribosomal RNA genes and spacers. These primers constitute a mainstay of fungal molecular systematics.

Research in the Buchanan Laboratory current focuses on
(1) Regulation of chloroplast enzymes, emphasizing the thylakoid lumen. Sheng Luan collaborates on this research
(2) Improvement in the nutritional properties of sorghum, concentrating on increasing the digestibility of protein and starch and on the presence and availability of amino acids. This project complements ongoing work on rapidly germinating barley and hypoallergenic wheat. Peggy Lemaux collaborates on the research with cereals.

The Coates Lab focuses on environmental microbiology: applied microbiology and bioremediation. We investigate removal of radioactive toxic metals, carcinogenic petroleum-based hydrocarbon contaminants, and toxic munitions byproducts from the environment. Recently, we identified dominant groups of bacteria that can transform perchlorate wastes into innocuous chloride, isolated and characterized more than 40 such bacteria, and identified the common biochemical pathway and genetic systems involved.

Cell specialization, cell communication and nonself recognition are crucial mechanisms in filamentous fungi. Neurospora crassa's experimental tractability make it a superb system to address microbial communication questions. We study communication and self-signaling mechanisms mediating hyphal fusion, and nonself recognition mechanisms resulting in programmed cell death. We use molecular biology, genetics, cell biology, genomics and bioinformatics to investigate the molecular and cellular basis of nonself recognition during the filamentous fungi lifecycle.

Viruses not only have an intimate association with disease, but also represent superb tools to deconstruct the pathways that govern cell function. The Glaunsinger lab investigates the mechanisms by which γ-herpesviruses promote global decay of cellular mRNAs during lytic infection; we are especially interested in possible interplay between the viral host shutoff factor(s) and cellular mRNA degradation machinery. We anticipate that analyzing such interactions may provide key insight into how these viruses modulate their cellular environment and events that regulate mammalian mRNA turnover.

The Jackson Lab researches how viruses elicit plant diseases, and devises mechanisms for disease control in transgenic plants. We work with three viruses: a plus sense monopartite RNA virus, tomato bushy stunt virus; a plus sense tripartite RNA virus, barley stripe mosaic virus; and a minus strand plant rhabdovirus, sonchus yellow net virus. We use genetic and biochemical analysis to investigate replication and movement of these viruses and to determine virus-host interactions culminating in disease.

Prokaryotes are highly organized cells with many ultrastructural similarities to eukaryotes. In addition to a highly dynamic cytoskeleton composed of homologues of actin, tubulin and intermediate filaments, many prokaryotes possess intracellular membranous organelles. My lab uses bacterial magnetosomes as a model system to study the molecular mechanisms governing the biogenesis and maintenance of prokaryotic organelles. Using a variety of approaches, we identify and investigate key genes involved in controlling magnetosome formation and function.

We study Amt and Rh proteins, which appear to be membrane channels for hydrated gases. They are the only two members of their superfamily. The Amt proteins are channels for ammonium. The Rh proteins, of Rh blood group substance fame, appear to be channels for carbon dioxide (probably H2CO3). We focus on the physiological roles of Rh and Amt proteins in the green alga Chlamydomonas reinhardtii. We continue collaborations to determine the structures of bacterial enhancer-binding proteins, which regulate transcription by the sigma54 holoenzyme form of RNA polymerase.

Our research group studies aspects of epiphytic bacteria that live on healthy plants' surfaces, emphasizing bacteria active in ice nucleation, causing frost damage to plants. We also study plant pathogenic bacteria that inhabit plant surfaces before infection. We use molecular genetic and ecological approaches to study how epiphytic bacteria interact with other microorganisms on plants, and with the plants on which they live. We seek to better understand adaptations epiphytic bacteria have evolved to exploit this unique habitat.

Photosynthetic organisms have evolved multiple mechanisms to cope with excessive light. We seek to identify and dissect these processes by isolating algal and plant mutants. We use a diverse set of techniques, including genetics, physiology, biochemistry, and molecular biology, focused on one particular species, Chlamydomonas reinhardtii, a unicellular green alga. We study the cellular processes involved in coping with reactive oxygen species produced in excessive light.

We isolate pure populations of Caulobacter swarmer cells and observe many parameters during their synchronous cell cycle progress including fluorescent protein localization, DNA content, and global transcriptional patterns. The sequenced Caulobacter genome expedites genetic manipulations and lets us search comprehensively for genes affecting processes of interest. We also pursue in vitro studies to determine how biochemical properties of individual regulatory proteins contribute to cell cycle progression and cellular asymmetry.

We seek to obtain a genetic, bio-chemical, and cell biological understanding of the mechanisms that enable gram-negative plant pathogens to cause disease on plants, and that allow plants to counteract bacterial pathogens.

Vitamin B12 is essential to most animals but is synthesized only by certain prokaryotes. Using genetic, biochemical, and bioinformatics approaches, we are investigating three areas related to vitamin B12 in bacteria: 1) the biosynthesis of 5,6-dimethylbenzimidazole (DMB), the least understood component of B12; 2) the function of B12 in the symbiotic interaction between the nitrogen-fixing bacterium Sinorhizobium meliloti and its plant host, alfalfa, and 3) the structure and function of novel B12-like compounds found in nature

We study the pattern and process of fungal evolution, both to understand the process and to make fungi the best models for evolutionary biology. We focus on the key evolutionary event that forms the tree of life: speciation. Recently we have documented species divergences, compared phylogenetic and biological species recognition, addressed the timing of species divergence, and evaluated selection acting on potentially adaptive genes. Now, we are using genetics and genomics to find genes that maintain species and facilitate adaptation.

My Lab has two projects underway 1) studying Agrobacterium-specific proteins and their molecular mechanisms responsible for producing a DNA-protein complex capable of plant cell transformation, and 2) researching Plasmodesmata structure.

We seek to understand the molecular and cellular basis of microbial pathogenesis and the mechanisms used by the host to defend against infection. Specifically, the lab focuses on the interaction of the facultative intracellular bacterial pathogen Listeria monocytogenes and mammalian cells.

We research two facets of development in the fruiting bacterium Myxococcus xanthus. The first concerns cell-cell communication and signal transduction; the second concerns the regulation of gene expression during cellular morphogenesis and development. Myxococcus exhibits complexity of multicellular behavior and morphogenetic development unusual among prokaryotes. We apply sophisticated genetic and molecular biological techniques to examine these processes.