Tag Archive for Cohan

Biology Team Samples Drought-Tolerant Bacteria in Death Valley

Nicole DelGaudio ’18 samples the rhizospheres of a juniper tree at about 7,000 feet above sea level.

Nicole DelGaudio ’18 samples the rhizosphere of a juniper tree.

This spring, a research team from Wesleyan traveled to Death Valley National Park to explore the ways bacteria diversifies in extreme environments.

Death Valley, located about 130 miles west of Las Vegas, is a below-sea-level basin known for being the hottest place on earth and driest place in North America. The average rainfall is less than 2 inches, annually.

“National parks are ideal for research, in general, because the land is protected indefinitely from commercial development,” said team leader Fred Cohan, professor of biology, professor of environmental studies. “Death Valley is a nice model system for exobiology because of its extreme habitat.”

Cohan, along with graduate student Jerry Lee, Bella Wiener ’19 and Nicole DelGaudio ’18, traveled to California May 29 through June 4. During this time, the researchers trekked through miles of parched — and often prickly — landscapes seeking to sample root soil, or rhizosphere, from various plant species, each over a wide range of elevations that differ notably in their temperatures.

Wesleyan Faculty, Students March for Science

Professor Laura Grabel, pictured sixth from left, attended the March for Science in New Haven, Conn.

Professor Laura Grabel, pictured sixth from left, attended the March for Science in New Haven, Conn.

Numerous Wesleyan faculty and students in the sciences attended the March for Science in different parts of the state and country on Earth Day, April 22.

Laura Grabel, the Lauren B. Dachs Professor of Science and Society, professor of biology, professor of environmental studies, professor of feminist, gender and sexuality studies, spoke at the New Haven march.

“I decided to march because science is being seriously threatened by the Trump administration,” she explained. “Trump has not filled almost all of the science positions, has no science advisor, and is using little evidence-based thinking in his decision making. Some of his appointments are puzzling and scary. From my perspective as a stem cell scientist, appointing Tom Price, who has consistently opposed embryonic stem cell research, as head of Health and Human Services presents a real danger to the future of this work just as therapies are entering clinical trials.”

Cohan Elected to Connecticut Academy of Science and Engineering

Fred Cohan

Fred Cohan

Frederick Cohan, professor of biology, professor of environmental studies, has recently been elected to the Connecticut Academy of Science and Engineering (CASE). Set to be inducted during the 42nd Annual Meeting and Dinner on May 22, 2017, Cohan will join 23 others as “Connecticut’s leading experts in science, technology, and engineering,” and the academy’s newest members during their ceremony at the University of Connecticut.

In line with CASE’s mission to honor those “on the basis of scientific and engineering distinction, achieved through significant contributions in theory or application,” Cohan’s work has led to the “development of a comprehensive new theory for the origin, maintenance, and evolutionary dynamics of bacterial species diversity that integrates ecological and genetic criteria; and to the initiation and co-development of associated software tools, which allow microbiologists to identify distinct bacterial species from DNA sequence data.”

Cohan is a graduate of Stanford University, where he earned a bachelor’s degree in biological sciences in 1975. He went on to earn his PhD in organismic and evolutionary biology from Harvard University in 1982. His professional work takes him across the biological and environmental world, including, but not limited to topics such as microbial ecology, evolutionary theory, origins of bacterial diversity, molecular systematics and gene cluster analysis, horizontal genetic transfer and bacterial transformation.

Cohan Presents Research at Microbial Ecology Symposium

cohanposter
Frederick Cohan, professor of biology, professor of environmental studies, presented his research poster, “Genetic Sweeps by Whisk Brooms and Garage Brooms — the Role of Ecology” at the 16th annual International Symposium on Microbial Ecology, held Aug. 21-26 in Montreal. Cohan presented his models on the origins of bacterial species, in particular that the rate a bacterial group forms new species is determined by the foods it consumes.

Microbial ecology is the study of microbes in the environment and their interactions with each other.

The International Society for Microbial Ecology is the principle non-profit scientific society for the burgeoning field of microbial ecology and its related disciplines. ISME fosters the exchange of scientific information by organizing international symposia as well as specific workshops, sponsoring publications, and promoting education/research. The society offers financial and travel awards during its symposia and provides services to the scientific as well as the wider community.

Cohan Published in Encyclopedia of Genetics, Genomics Publication

Fred Cohan, chair and professor of biology, professor of environmental studies, is the co-author of “Species,” published in the Encyclopedia of Genetics, Amsterdam, Elsevier, 2013; “Accuracy and efficiency of algorithms for demarcating bacterial ecotypes from DNA sequence data,” published in BMC Genomics, 2013; and “Speedy speciation in a bacterial microcosm: New species can arise as frequently as adaptations within a species,” published in the ISME Journal’s Advance Online Publication, 2013.

Hingorani Group Publishes 8 Papers on DNA Mismatch Repair

A research group led by Manju Hingorani, associate professor of molecular biology and biochemistry, has published eight papers in 2011-2012 on the mechanisms of DNA replication and repair proteins, independently and in collaboration with research groups at Wesleyan and other national and international universities.

The papers are:

“Large conformational changes in MutS during DNA scanning, mismatch recognition and repair signaling,” published in The EMBO Journal, 2012 (in press).

The Variable Sub-domain of Escherichia coli SecA functions to regulate in the SecA ATPase Activity and ADP release,” published in the Journal of Bacteriology, 2012 (March 2 Epub). Don Oliver, the Daniel Ayres Professor of Biology, professor of molecular biology and biochemistry, was the lead investigator and Fred Cohan, professor of biology, professor of environmental studies, was a co-author on this paper.

Single-molecule multiparameter fluorescence spectroscopy reveals directional MutS binding to mismatched bases in DNA,” published in Nucleic Acids Research, 2012 (Feb, 24 Epub).

Biochemical analysis of the human mismatch repair proteins hMutSαMSH2G674A-MSH6 and MSH2-MSH6T1219D,” published in the Journal of Biological Chemistry, 2012 (Jan. 25 Epub).

ATP Binding and Hydrolysis-Driven Rate-Determining Events in the RFC-Catalyzed PCNA Clamp Loading Reaction,” published in the Journal of Molecular Biology, Feb. 17, 2012; 416(2), pages 176-91.

A Central Swivel Point in the RFC Clamp Loader Controls PCNA Opening and Loading on DNA,” published in the Journal of Molecular Biology, Feb. 17, 2012; 416(2), pages 163-75.

Human MSH2 (hMSH2) protein controls ATP processing by hMSH2-hMSH6,” published in the Journal of Biological Chemistry, Nov. 18, 2011; 286(46), pages 40287-95.

Dynamical allosterism in the mechanism of action of DNA mismatch repair protein MutS,” published in the Biophysical Journal, Oct. 5, 2011;101(7), pages 1730-9. David Beveridge, the Joshua Boger Professor of the Sciences and Mathematics, was the lead investigator on this paper.

5 Questions With . . . Fred Cohan on Moneyball, Biology

Fred Cohan

This issue, 5 Questions talks about the connections between the Moneyball and biology with Fredrick Cohan, professor of biology.

Q: Fred, you’ve been talking about how the data mining revolution in baseball, championed by the Michael Lewis book Moneyball and the recent movie of the same name starring Brad Pitt, can change science in general and biology, specifically. Really?

A: Absolutely! On the surface, Moneyball is the story of Billy Beane, the general manager of the Oakland A’s, who found a way to lead his poverty-stricken team to success against teams with many times the payroll of Oakland. But Moneyball is really about the thrill and triumph of data mining—how old data can be gleaned for meaning in ways that were never intended when the data were originally collected. Beane and his colleagues challenged the time-honored “holy trinity” of batting average, home runs, and runs batted in (RBIs) as the essence of a player’s offensive value. They were working off theories developed by Bill James, who posited in the 1970s that these traditional statistics, which everyone in the game knew provided the “truth” about a player’s value, were really imperfect measurements. James mined the data and developed other measurements, such as O.B.P. (on base percentage),

Cohan on Baseball, Bacteria and Koufax’s Perfect Game

In an op-ed for The Los Angeles Times, Frederick Cohan, professor of biology, professor of environmental studies, discusses how his experience as a child watching perhaps the greatest “perfect game” in baseball history – The Los Angeles Dodgers’ Sandy Koufax’s 1-0 victory over the Chicago Cubs in 1965 – provided lessons for the mining of old data for both baseball front offices and biologists such as himself who specialize in studying bacteria. Read the op-ed here.

Cohan Published in Microbiology, Infectious Diseases Journals

Papers, articles and book chapters by Fred Cohan, professor of biology, are published in several publications including:

“Community ecology of hot spring cyanobacterial mats: predominant populations and their functional potential,” published in ISME Journal: Multidisciplinary Journal of Microbial Ecology, 2011;

“Influence of molecular resolution on sequence-based discovery of ecological diversity among Synechococcus populations in an alkaline siliceous hot spring microbial mat,” published in Applied and Environmental Microbiology 77:1359-1367, 2011;

“Are species cohesive?—A view from bacteriology,” published in Bacterial Population Genetics: A Tribute to Thomas S. Whittam, American Society for Microbiology Press, Washington, pages 43-65, 2011;

“Species,” a chapter published in Elsevier’s Encyclopedia of Genetics. Oxford: Elsevier, in press;
“Metagenomic approaches for the identification of microbial species,” a book chapter published in the Handbook of Molecular Microbial Ecology, Volume I, pages 105-109, 2011;

Cohan and Jane Wiedenbeck ’10 are the co-authors of the invited article, “Origins of bacterial diversity through horizontal gene transfer and adaptation to new ecological niches,” published in FEMS Microbiology Reviews 35:957–976, in print.

Cohan and Ph.D. candidate Sarah Kopac are the co-authors of “A theory-based pragmatism for discovering and classifying newly divergent bacterial species,” published in Genetics and Evolution of Infectious Diseases,  pp. 21-41, 2011.

In Current Biology, Cohan Muses on Bacteria, Baseball

In a lengthy Q&A in the June 7 issue of Current Biology, Professor of Biology Fred Cohan talks about the evolution of bacteria, his favorite course at Wesleyan – and the legendary 1965 baseball game that impressed upon him the power and possibility of data. For the full Q&A, click here.

Cohan, Kopac Awarded Grant for Death Valley Bacteria Study

Fred Cohan, professor of biology, professor of environmental studies, and biology graduate student Sarah Kopac received a $20,000 Connecticut Space Grant Consortium Training Grant on March 9. The award, which is subcontracted through the University of Hartford, supports a study titled “The Speciation of Bacillus Subtilis along a natural Salinity Gradient in Death Valley.”