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Strongest Spider Silk Produced in Bacteria

Engineering students from Northeastern University worked with Professor and Chair David Kaplan in the Department of Biomedical Engineering to engineer a theoretical method for producing spider silk in bacterial cells at currently unmatched concentrations. Silk from the Caerostris darwini spider of Madagascar is more robust than any material at ten times the toughness of Kevlar.

Credit: Thinkstock

The team’s project won first place at this year’s New Eng­land Bio­engi­neering Con­fer­ence.

Read more about the technology in Kaplan’s paper in Proceedings of the National Academy of Sciences (PNAS).

Xiao-Xia Xia, Zhi-Gang Qian, Chang Seok Ki, Young Hwan Park, David L. Kaplan, and Sang Yup Lee. Native-sized recombinant spider silk protein produced in metabolically engineered Escherichia coli results in a strong fiber. PNAS, 2010; DOI: 10.1073/pnas.1003366107

This story by Angela Herring first appeared in news@Northeastern on May 10, 2013.


Prof Panzer Explains Solar Energy Storage Options

Assistant Professor Matthew Panzer of the Department of Chemical and Biological Engineering wrote an “Ask the Expert” piece for TuftsNow on how options for storing solar energy.

Solar cells, also known as photovoltaics, convert sunlight directly into electricity. Photo: © Elena Elisseeva/DepositPhoto

“When the sun shines, we can store the electricity generated by solar cells or steam-driven turbines by using batteries (technically energy stored as electrochemical potential) or supercapacitors (energy stored in an electric field, due to the spatial separation of positive and negative charges). Then we can release electrical energy when it is cloudy or at night.

There are at least two other ways to store solar energy for use later. First, the thermal energy of concentrated sunlight can be stored in the heat capacity of a molten salt (the liquid form of an ionic compound like sodium chloride) at a high temperature. When electricity is needed later, heat is transferred from the molten salt to water, using a heat exchanger to generate steam to drive a turbine.”

This story first appeared in TuftsNow, May 13, 2013.


BEST Student Engages Girls in STEM

Student Anecia Richards presented a workshop on robots at the second annual Women’s Innovation Symposium in Engineering in Brooklyn’s Poly Prep Country Day School. Anecia Richards, a Poly alumna, electrical engineer, and student in Tufts’ Bridge to Engineering Success at Tufts (BEST) program, presented a workshop taught the high school students how to build and program a LEGO robot.

First reported in the Brooklyn Daily Eagle, May 8, 2013.


Alumna McCarthy Nominated to Head the EPA

Gina McCarthy, EG81

President Obama nominated Gina McCarthy, EG81, to head the U.S. Environmental Protection Agency, and she was recently confirmed by the U.S. Senate. McCarthy, who earned a joint M.S. degree in environmental health engineering and planning and policy, is the former EPA administrator for the Office of Air and Radiation. McCarthy was also named a recipient of Graduate Studies’ Outstanding Service Award

In a 2009 interview with Tufts E-News, McCarthy said, “I don’t separate health issues from environmental issues or environmental issues from energy issues. I try to see it from the standpoint of human beings and what they need to have a sustainable world. I ended up in the environmental world because I saw the most direct overlap between what is happening in peoples’ health and the pollution they were being exposed to.”


Cortese Wins EPA Lifetime Achievement Award

Anthony D. Cortese, E68, EG72, received a Lifetime Achievement award from the Environmental Protection Agency at the 2013 Environmental Merit Award ceremonies held June 26 in Boston. Cortese is a senior fellow of Second Nature, an organization based in Boston and committed to promoting sustainability through higher education. Cortese received another Environmental Merit Award on behalf of Second Nature, which was nominated in the EPA’s Environmental, Community, Academia & Nonprofit category.

Cortese_EPA-LifetimeAchievment

Curt Spalding (left), Regional Administrator, EPA New England, honors Anthony D. Cortese, E68, EG72, (third from left) with an EPA Lifetime Achievement award along with award recipients Ken Kimmell and Ira Leighton.

Cortese co-founded Second Nature with then-US Sen. John Kerry of Massachusetts; Kerry’s wife, Teresa Heinz Kerry; and environmentalist and educator Bruce Droste. As president of Second Nature from 1993 to 2012, Cortese organized the American College & University Presidents’ Climate Commitment and co-founded both the Association for the Advancement of Sustainability in Higher Education and the Higher Education Association Sustainability Consortium. Cortese was formerly the commissioner of the Massachusetts Department of Environmental Protection and was the first dean of environmental programs at Tufts University. At Tufts, he founded the Tufts Environmental Literacy Institute in 1989 that helped integrate environmental and sustainability perspectives into more than 175 courses.

Cortese also organized the effort that resulted in the internationally acclaimed Talloires Declaration of University Leaders for a Sustainable Future in 1990, now signed by more than 350 presidents and chancellors in more than 50 countries. Cortese is a frequent consultant on sustainability to higher education, industry and non-profit organizations.


By Hook or By Crook

Incoming Assistant Professor Jeff Guasto (Ph.D., Brown University) has been working on understanding how single-celled organisms, like bacteria, get around. Guasto, a postdoctoral researcher in MIT’s Department of Civil and Environmental Engineering, and his colleagues have been studying how microbes, such as marine bacteria, use their flagella to propel themselves forward, backward, and change direction. Researchers had observed the marine bacteria changing direction using a flicking motion of the flagellum, but they didn’t understand how it was happening.

Motile marine bacteria exploit a buckling instability of the flexible hook (green) at the base of their flagellum (yellow) to change swimming direction, turning what is otherwise a structural failure into a fundamental biological function. GRAPHIC: KWANGMIN SON, JEFFREY GUASTO, GLYNN GORICK AND ROMAN STOCKER

Using high-speed video shot a 1,000 frames per second, the MIT team was able to record the flicking motion of bacteria swimming forward. They determined that the flick occurs when the “hook,” a small flexible rod connecting the flagellum to the cell’s internal motor, buckles.

“A single actuator, the flagellum, enables both propulsion and turning in these bacteria,” Guasto says. “This is a well-known principle in robotics called ‘underactuation,’ but it is rarely considered at the micrometer scale.”

“The mechanism of turning by buckling represents one of the smallest examples in nature of a biological function stemming from controlled mechanical failure and reveals a new role for flexibility in biological materials, which could inspire new microrobotic solutions in medicine and engineering,” the authors say in their July 7 paper in Nature Physics. http://dx.doi.org/10.1038/nphys2676