Roberto Kolter is professor of microbiology, emeritus, at Harvard Medical School, an author, and past president of the American Society for Microbiology. Kolter has been a professor at Harvard Medical School since 1983 and was Co-director of Harvard's Microbial Sciences Initiative from 2003-2018. During the 35-year term of the Kolter laboratory from 1983 to 2018, more than 130 graduate students and postdoctoral trainees explored an eclectic mix of topics gravitating around the study of microbes. Kolter is a fellow of the American Association for the Advancement of Science and of the American Academy of Microbiology. As professor emeritus, Kolter has continued his involvement in science by communicating microbiology to scientific and general audiences. Since 2016, Kolter has been co-blogger (with Moselio Schaechter) of the popular microbiology blog, Small Things Considered. From 2014 to 2018, Kolter and Scott Chimileski developed two exhibitions at the Harvard Museum of Natural History: World in a Drop, open in 2017, and Microbial Life, open through 2020. In parallel, Chimileski and Kolter wrote the book Life at the Edge of Sight: A Photographic Exploration of the Microbial World (Harvard University Press, 2017). During a 2018 interview at EAFIT University in Colombia, Kolter explained that he is "in a more contemplative phase of his career," adding that he is enjoying "being able to exercise a little more the 'Ph' (Philosophy) of my PhD".
Early life, education and academic career Kolter was born and raised in Guatemala. He received a Bachelor of Science degree in biology from Carnegie Mellon University in 1975 and a PhD in biology from the University of California, San Diego in 1979. He was then a Helen Hay Whitney Postdoctoral Fellow at Stanford University with Charles Yanofsky from 1980 to 1983. Kolter joined the faculty at Harvard Medical School as an assistant professor in 1983, was promoted to associate professor in 1989, professor in 1994, and became professor emeritus upon his retirement from running a research laboratory in 2018.
Research
Summary The research activities of Kolter's laboratory at Harvard Medical School from 1983 to 2018 encompassed several major parallel lines of investigation and spanned many interrelated subfields of microbiology. The overarching theme of the laboratory was to use genetic approaches to study physiological processes (and associated emergent properties) that bacteria have evolved to respond to stressful conditions in the environment, like starvation or limited nutrients, or as a result of ecological interactions with other living organisms. The eclectic nature of Kolter's research program was also a result of his policy of encouraging postdoctoral scientists to explore independent interests. In an interview with Nature in 2015, Kolter was quoted on this mentorship style: "I let postdocs explore what they want to explore, as long as it is within the sphere of my interest." In total, Kolter has co-authored over 250 research and other scholarly articles which together have been cited over 50,000 times. Kolter's research group was influential in the study of bacterial transport systems known as ABC exporters, published some of the earliest examples of experimental evolution through investigations of the stationary phase of bacterial growth, and was foundational in genetic studies of bacteria adhered to surfaces (living within communities called biofilms). The lab popularized the concept of bacterial biofilm formation as developmental or multicellular microbial processes, and pioneered genetic studies of cellular differentiation, signaling, and division of labor in bacteria. In addition, his group has worked on other aspects of bacterial physiology, the domestication of lab strains of bacteria, microbiome ecology, interactions between plants and bacteria, bacterial respiration processes, and bioactive compound discovery. Some of Kolter's significant scientific contributions are categorized below in chronological order.
Major topics of investigation
Regulation of DNA replication As a graduate student, Kolter's research provided early evidence for what was called the "replicon hypothesis," proposed by Jacob, Brenner and Cuzin in 1962. His work defined an origin of DNA replication that led to the development of many suicide cloning vectors still in use today.
Kolter, R; Helinski, DR (1978). "Construction of plasmid R6K derivatives in vitro: characterization of the R6K replication region". Plasmid. 1 (4): 571–80. doi:10.1016/0147-619X(78)90014-8. PMID 372982. Kolter, R; Inuzuka, M; Helinski, DR (Dec 1978). "Trans-complementation-dependent replication of a low molecular weight origin fragment from plasmid R6K". Cell. 15 (4): 1199–208. doi:10.1016/0092-8674(78)90046-6. PMID 728998. S2CID 20082813. Kolter, R; Helinski, DR (1982). "Plasmid R6K DNA replication. II. Direct nucleotide sequence repeats are required for an active gamma-origin". J Mol Biol. 161 (1): 45–56. doi:10.1016/0022-2836(82)90277-7. PMID 6296394.
Peptide antibiotic biosynthesis and ABC exporters As a new faculty member at Harvard Medical school in the 1980s, Kolter's research group made use of Escherichia coli as a model organism for understanding the molecular genetics of antibiotic biosynthesis. During the course of this work the group was among the first to characterize ABC exporters, today known to be one of the most important membrane protein systems that move molecules across the cell membrane.
Gilson, L; Mahanty, HK; Kolter, R (1990). "Genetic analysis of an MDR-like export system: the secretion of colicin V". EMBO J. 9 (12): 3875–84. doi:10.1002/j.1460-2075.1990.tb07606.x. PMC 552155. PMID 2249654. Fath, MJ; Kolter, R (1993). "ABC transporters: bacterial exporters". Microbiol. Rev. 57 (4): 995–1017. doi:10.1128/mmbr.57.4.995-1017.1993. PMC 372944. PMID 8302219. Yorgey, P; Lee, J; Kördel, J; Vivas, E; Warner, P; Jebaratnam, D; Kolter, R (1994). "Posttranslational modifications in microcin B17 define an additional class of DNA gyrase inhibitor". Proc Natl Acad Sci U S A. 91 (10): 4519–23. Bibcode:1994PNAS...91.4519Y. doi:10.1073/pnas.91.10.4519. PMC 43817. PMID 8183941.
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