Baskaran Wins NSF-CAREER award to pursue research on active fluids

Dr. Aparna Baskaran of the Physics Department has been awarded the prestigious CAREER grant from the National Science Foundation that is a highly competitive development grant for early career tenure track faculty members. This grant will fund the research ongoing in Dr. Baskaran’s group on dynamics in active materials. Active materials are a novel class of complex fluids that are driven out of equilibrium at the level of individual entities. Examples of such systems include bacterial suspensions, cytoskeletal filaments interacting with motor proteins and inanimate systems such as self-propelled phoretic colloidal particles. The theoretical challenge in understanding these systems lies in the fact that, unlike traditional materials, we no longer have the scaffold of equilibrium on which to base the theoretical framework.  At the practical front, these materials exhibit novel properties not seen in regular materials.  Further, they form the physical framework of biological systems  in that regulatory mechanisms modulate the mechanical properties of this material in response to environmental stimuli.  Dr. Baskaran’s research in this field will be done in collaboration with the groups of Dr. Michael Hagan, Dr. Zvonimir Dogic and Dr. Bulbul Chakraborty. It will enhance and complement the MRSEC research activities in the active materials thrust.

Figure Caption : Videos of example systems for active materials. A) A fish school exhibiting complex collective swimming. B) Swarming at the edge of an E. Coli Bacterial Colony. C) Cytoplasmic streaming inside the yolk of a fertilized cell.

NIH fellowships for Kuzirian and Ghiretti support neural development research

Marissa Kuzirian and Amy Ghiretti, graduate students in the lab of Dr. Suzanne Paradis, were each recently awarded Ruth L. Kirschstein National Research Service Awards for Individual Predoctoral Fellows (F31s) from the National Institutes of Health. Marissa’s 2.5-year award from the National Institute of Neurological Disorders and Stroke funds research to explore the role of Semaphorin4D and its receptor, PlexinB1, in regulating inhibitory synapse development and ultimately setting up proper neural connections in the mammalian CNS. Amy’s 2-year award from the National Institute on Drug Abuse funds a collaborative project between the Paradis, Lau, and Van Hooser labs here at Brandeis to elucidate the function of Rem2 in mediating experience-dependent changes in dendritic morphology in a living, intact animal system.

The basis for Marissa and Amy’s work comes from research into neurodevelopmental disorders such as Autism Spectrum Disorders (ASDs), as well as drug abuse and addiction. Proteins that regulate neurodevelopmental processes such as synapse development and dendritic morphology are important in both neurological disorders and drug addiction. Proper communication between neurons depends on the precise assembly and development of synaptic connections. The transmembrane protein Semaphorin4D (Sema4D) is necessary for proper GABAergic synapse formation, as knockdown of expression in the postsynaptic neuron by RNAi leads to a decrease in GABAergic synaptic density in cultured neurons (Paradis et al 2007). Marissa’s work will further explore this role of Sema4D in GABAergic synapse development.

Inhibitory synapses are identified in white along dendrites of a rat hippocampal neuron. Synapses are defined as sites of overlap between the postsynaptic protein GABAA receptor subunit γ2 (red) and the presynaptic protein GAD65 (blue) visualized by immunostaining. Neurons are visualized by immunostaining for MAP2 (green).

Marissa’s preliminary results demonstrate that adding the soluble, extracellular domain of Sema4D to cultured hippocampal neurons is sufficient to drive GABAergic synapse formation. This increase depends on the expression of Sema4D’s receptor, PlexinB1. Thus, Marissa’s work defines PlexinB1 as a novel receptor mediating GABAergic synapse formation in response to Sema4D in the mammalian CNS. The goal of Marissa’s project is to elucidate the role of Sema4D and its receptor, PlexinB1, in GABAergic synapse development. In experiments she proposed, she hypothesizes that Sema4D acts to initiate assembly of GABAergic synaptic proteins such as GABAA receptors and gephyrin through its receptor PlexinB1. This will be tested using a variety of imaging techniques in cultured hippocampal neurons, including confocal and time-lapse imaging, to measure the mobility and accumulation of GABAergic synaptic proteins in neurons after treatment with soluble Sema4D. The experiments will not only greatly expand our understanding of a novel receptor-ligand pair in GABAergic synapse development, it will inform as to some of the basic mechanisms underlying GABAergic synaptogenesis.

Molecular mechanisms, such as the Sema4D-PlexB1 interaction described above, are critical for the ability of the central nervous system (CNS) to respond to extracellular stimuli and make corresponding changes in the structure and function of a neuron. At the behavioral level, this plasticity allows an organism to respond to a changing environment appropriately in order to survive. At the level of individual neurons, this is reflected in changes in gene expression that occur in response to a variety of stimuli, including alterations in neuronal network activity. The goal of Amy’s work is to characterize a direct molecular link between changes in neuronal activity and changes in dendritic morphology.

A neuron in the optic tectum of a Xenopus tadpole; Green Fluorescent Protein expression allows the dendrites to be visualized.

Amy has previously implicated the protein Rem2, a type of signaling molecule known as a GTPase, as a mediator of such neurodevelopmental processes as excitatory synapse formation and dendritic morphology (Ghiretti & Paradis 2011). The expression of Rem2 in individual neurons is upregulated following increased neuronal activity, suggesting that it may serve as a direct link between changes in activity and corresponding changes in the structure and function of neurons. Her recently funded work will utilize Xenopus laevis tadpoles to study the effects of visual experience (by exposing the tadpoles to a light stimulus) on Rem2 expression, and in turn, how Rem2 mediates experience-dependent changes in the morphology of neurons in a region of the brain known as the optic tectum, where visual processing takes place. Ultimately, a full understanding of how Rem2 functions to shape the morphology of neurons in an intact system may help to inform knowledge of how the human brain changes as a result of neurological disorders or drug abuse, and aid in the development of more effective treatments to prevent these changes from occurring.

Drew named McKnight Scholar

Patrick Drew (PhD ’04, Neuroscience) has been named a 2012 McKnight Scholar Award recipient by the McKnight Endowment Fund for Neuroscience. Drew did his Ph.D. research at Brandeis with Larry Abbott, did a postdoc at UCSD with David Kleinfeld, and most recently has started up his own lab at Penn State as an Assistant Professor of Engineering Science & Mechanics, and as part of their Center for Neural Engineering. Drew’s lab is primarily focused on understanding the neural circuits and signaling pathways that dynamically route the brain’s blood supply. Understanding the regulation is not only important in itself, but it is involved in medical problems such as stroke and dementia, and because changes in blood flow form the basis for functional magnetic resonance imaging, from which changes in brain activity are inferred.

Children’s Leukemia Research Award to Fund Myosin Research

(from left to right) Director of Rosenstiel Center Jim Haber, Professor Carolyn Cohen, Dr. Jerry Brown, Anthony Pasqua, President of the Childrens Leukemia Research Association

On April 24, a Children’s Leukemia Research Association (CLRA) award was presented to Jerry Brown, a Senior Research Scientist who works with Carolyn Cohen at the Rosenstiel Basic Medical Sciences Research Center. The award will help fund research on structures of α-helical coiled-coils, in particular those from myosin implicated in certain leukemias. The α-helical coiled coil is a common dimerization motif in proteins and is implicated in many normal physiological as well as pathological processes. Many cases of acute myeloid leukemia involve the aberrant fusion of the transcription factor, CBFβ, to a long portion of the smooth muscle myosin rod, which is predicted from its amino acid sequence to form an α-helical coiled coil. A major aim of the proposed research is thus to crystallize and determine the atomic structures of the segment of the myosin rod nearest this fusion point, both in its normal unfused physiological state and when aberrantly fused to CBFβ. A related aim of the research is to understand how the conformations of α-helical coiled coils in general are affected by attached structures. Accomplishment of these aims may provide a structural basis for the rational design of drugs that can selectively disrupt the activity of the pathologically fused protein.

In addition to Dr. Brown and Professor Cohen, the award presentation was attended by their laboratory researchers Senthil Kumar, Ludmila Reshetnikova, and Elizabeth O’Neall-Hennessey, Rosenstiel Director James Haber, Brandeis Office of Research Administration Associate Director Patricia McDonough, Rosenstiel Department Operations Manager Anahid Keshgerian, CLRA President Anthony Pasqua, his daughter Susan (Pasqua) Bogue, a survivor of leukemia, and Nancy Golden and three of her children.   The award is named after another daughter of Nancy Golden, Amy Golden Uleis, who lost her battle with cancer at age 52 and was a graduate of Brandeis. The award presentation was accompanied by a photo-op and a small reception held at Rosenstiel.

Eve Marder wins 2012 Karl Spencer Lashley Award

photograph (c) American Philosophical Society 2012; Frank Margeson, photographer.

Professor Eve Marder was awarded  the 2012 Karl Spencer Lashley Award by the American Philosophical Society at their annual meeting in Philadelphia in April, “in recognition of her comprehensive work with a small nervous system, demonstrating general principles by which neuromodulatory substances reconfigure the operation of neuronal networks.” Marder, the Victor and Gwendolyn Beinfield Professor of Neuroscience, currently serves in the capacity of Head of the Division of Science at Brandeis, yet manages to direct and inspire an incredibly productive laboratory of students and postdocs who continue to extend our understanding how circuit function arises from the intrinsic properties of individual neurons and their synaptic connections, using their favorite model system, the  crustacean stomatogastric nervous system. This award follows close on the heels of the George A. Miller Prize from the Cognitive Neuroscience Society, awarded in March 2012.

See also story at Brandeis NOW.

2012 Brandeis Achievement Awards

Four out of five 2012 recipients of Brandeis Achievement Awards are science majors.

  • Fiona Aguilar  (biology, Haber lab)
  • Daniel Boyle (biochemistry and neuroscience, Lovett lab)
  • Ariana Boltax (biology and chemistry)
  • Sara Shahanaghi (economics and mathematics)

For the full story, see Brandeis NOW.

Rosbash, Hall, and Young Honored with Canada Gairdner International Award

Brandeis science faculty members Michael Rosbash and Jeff Hall were named today as 2012 recipients of the Canada Gairdner International Award, one of the world’s top prizes for biomedical research. Together with Michael Young (Rockefeller Univ.), they were honored “for pioneering discoveries concerning the biological clock responsible for circadian rhythms”. The trio has previously been honored with the 2011 Louis Gross Horwitz Prize and the 2009 Gruber Neuroscience Prize for this research.

The Gairdner Foundation in Toronto began giving awards in 1959 to recognize and reward the world’s most creative and accomplished biomedical scientists. So far about a quarter of the recipients have gone on to win a Nobel Prize. Also honored this year (for other work) were neuroscientist Tom Jessell and immunologist Jeffrey Ravetch.

Hall is now Professor Emeritus of Biology, and his influence is felt strongly in the strong Drosophila genetics community at Brandeis even though his lab is gone. The Rosbash lab continues to be a force for innovation in research on circadian regulation and mRNA processing. To hear more about Rosbash lab research, come to Wednesday seminar on April 4, when Michael will be the speaker. The title of his seminar is: 37 years at Brandeis (but who’s counting): Gene Expression and Circadian Rhythms.

Here’s some video the Gairdner Foundation posted on YouTube:

More information about this story at the following sites:

Pololi receives leadership development award

Linda Pololi, Senior Scientist at the Women’s Studies Research Center, is the recipient of the 2011 Women in Medicine and Science Leadership Development Award from the Association of American Medical Colleges. Dr. Pololi serves as director and principal investigator for the National Initiative on Gender, Culture and Leadership in Medicine: C – Change. The goal of the Initiative is to foster change in the culture of academic medicine to support realizing the full potential of all faculty.

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