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Richard Losick
Harvard University,
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Richard Losick is the Maria Moors Cabot Professor of Biology and a Howard Hughes Medical Institute Professor at Harvard University, US. He received his A.B. from Princeton University, his Ph.D. from the Massachusetts Institute of Technology, US, and then became a Junior Fellow of the Harvard Society of Fellows when he began his studies on RNA polymerase and the regulation of gene transcription in bacteria. He is a past Chairman of the Departments of Cellular and Developmental Biology and Molecular and Cellular Biology at Harvard University. He received the Camille and Henry Dreyfuss Teacher-Scholar Award, and he is a member of the US National Academy of Sciences, a Fellow of the American Academy of Arts and Sciences, a Member of the American Philosophical Society, a Fellow of the American Association for the Advancement of Science, and a Fellow of the American Academy of Microbiology. He is the 2007 recipient of the Selman A. Waksman Award of the US National Academy of Sciences and a 2009 recipient of the Canada Gairdner Award. |
Saturday 4 September, 18:15 - 19:00
Life & death of a microbial community
Bacteria of many kinds form architecturally complex communities of cells on surfaces. These communities are known as biofilms and are of great importance in medicine, agriculture and industry. As biofilms age, nutrients become limiting and waste products accumulate. Hence, it is advantageous for the biofilm-associated bacteria to return to a planktonic existence of free living cells. Thus, biofilms typically have a finite lifetime, characterized by eventual disassembly. I will discuss the mechanisms that govern the assembly and disassembly of biofilms by the soil bacterium Bacillus subtilis. Cells in the B. subtilis biofilm are held together by an extracellular matrix that consists of an exopolysaccharide and an amyloid-like fiber. I will report that matrix production is governed by a novel double-negative loop involving protein-protein and protein-DNA interactions. The loop behaves like an epigenetic switch and when switched on locks cells in the state of matrix production. How do cells exit the biofilm and return to a planktonic existence? I will report that late in the life cycle of the biofilm two racemase genes are switched on that direct the synthesis of the D-amino acids D-tyrosine, D-leucine, D-methionine and D-tryptophan. These D-amino acids are incorporated into the cell wall, causing cells in the matrix to jettison the amyloid fibers. Surprisingly, and potentially of important practical significance, D-amino acids, which are known to be produced by many bacteria in stationary phase, seem to serve as a signal to trigger biofilm disassembly by a wide range of bacterial species.
updated on 25 August
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Frans de Waal EMORY University, Atlanta, US
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Frans de Waal is a Dutch-born ethologist/biologist known for his work on the social intelligence of primates. His first book, Chimpanzee Politics (1982) compared the schmoozing and scheming of chimpanzees involved in power struggles with that of human politicians. Ever since, he has drawn parallels between primate and human behaviour, from peacemaking and morality to culture. His scientific work has been published in hundreds of technical articles in journals such as Science, Nature, Scientific American, and outlets specialized in animal behaviour. His popular books - translated into fifteen languages - have made him one of the world's most visible primatologists. His latest books are Our Inner Ape (2005, Riverhead) and The Age of Empathy (2009, Harmony Books). He is C. H. Candler Professor in the Psychology Department of Emory University and Director of the Living Links Center at the Yerkes National Primate Center, in Atlanta, Georgia. He has been elected to the National Academy of Sciences (US), the American Academy of Arts and Sciences, and the Royal Dutch Academy of Sciences. In 2007, Time selected him as one of the Worlds' 100 Most Influential People Today. |
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Sunday 5 September, 18:00 - 19:00
Prosocial Primates: Empathy, Fairness & Cooperation
The possibility that animals have empathy and sympathy has received little systematic attention due to an excessive fear of anthropomorphism and a taboo on animal emotions. Actual animal behavior, however, would lead one to agree with Charles Darwin that "Many animals certainly sympathize with each other's distress or danger." In my own work with monkeys and apes, I have found many cases of one individual coming to another's rescue in a fight, putting an arm around a previous victim of attack, or other emotional responses to the distress of others. In fact, the entire communication system of nonhuman primates seems emotionally mediated. Empathy has many levels, from basic perception-action mechanisms (probably related to mirror neurons) to ever greater cognitive elaborations that include perspective-taking. The basic forms probably exist in all mammals as they serve important survival functions for animals with vulnerable young. The higher forms of empathy require a sharp self-other distinction found only in humans over the age of two, and a few other large-brained species: apes, dolphins, and elephants. All of these empathy levels will be discussed as well as recent experiments on primate prosocial tendencies (assisting others) and their aversion for inequity (unequal rewards for same task), which has been proposed as an essential component of the human sense of fairness.
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