Small heat shock proteins are necessary for heart migration and laterality determination in zebrafish
Jamie L. Lahvic a,1, Yongchang Ji b, Paloma Marin a, Jonah P. Zuflacht a,2, Mark W. Springel a,3, Jonathan E. Wosen a, Leigh Davis a,4, Lara D. Hutson a,5, Jeffrey D. Amack b,
Martha J. Marvina,*
a Williams College Department of Biology, 59 Lab Campus Drive, Williamstown, MA 01267, USA
b Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA
Small heat shock proteins (sHsps) regulate cellular functions not only under stress, but also during normal development, when they are expressed in organ-specific patterns. Here we demonstrate that two small heat shock proteins expressed in embryonic zebrafish heart, hspb7 and hspb12, have roles in the development of left–right asymmetry. In zebrafish, laterality is determined by the motility of cilia in Kupffer’s vesicle (KV), where hspb7 is expressed; knockdown of hspb7 causes laterality defects by disrupting the motility of these cilia. In embryos with reduced hspb7, the axonemes of KV cilia have a 9þ0 structure, while control embyros have a predominately 9þ2 structure. Reduction of either hspb7 or hspb12 alters the expression pattern of genes that propagate the signals that establish left–right asymmetry: the nodal-related gene southpaw (spaw) in the lateral plate mesoderm, and its downstream targets pitx2, lefty1 and lefty2. Partial depletion of hspb7 causes concordant heart, brain and visceral laterality defects, indicating that loss of KV cilia motility leads to coordinated but randomized laterality. Reducing hspb12 leads to similar alterations in the expression of downstream laterality genes, but at a lower penetrance. Simultaneous reduction of hspb7 and hspb12 randomizes heart, brain and visceral laterality, suggesting that these two genes have partially redundant functions in the establishment of left–right asymmetry. In addition, both hspb7 and hspb12 are expressed in the precardiac mesoderm and in the yolk syncytial layer, which supports the migration and fusion of mesodermal cardiac precursors. In embryos in which the reduction of hspb7 or hspb12 was limited to the yolk, migration defects predominated, suggesting that the yolk expression of these genes rather than heart expression is responsible for the migration defects.
J.L. Lahvic et al. / Developmental Biology 384 (2013) 166–180
Oxyntomodulin increases intrinsic heart rate through the glucagon receptor
Auyon Mukharji1, Daniel J. Drucker2, Maureen J. Charron3, Steven J. Swoap1,*
Two hormones from the gastrointestinal tract, glucagon and oxyntomodulin (OXM), vigorously elevate the intrinsic heart rate (IHR) of mice. We have previously shown that OXM influences murine heart rate (HR) independent of the glucagon-like peptide 1 (GLP-1) receptor. Here, we demonstrate using radiotelemetry in mice deficient in the glucagon receptor (Gcgr −/−) that both OXM and glucagon require the glucagon receptor for their chronotropic effects on the heart. Furthermore, we found that other hormones associated with hunger and satiety (ghrelin, leptin, and PYY3-36) had no effect on IHR, while cholecystokinin moderately elevated the IHR. Finally, the resting HR of Gcgr −/− mice was higher than in control mice (Gcgr +/+ and Gcgr +/−) at thermal neutral temperature (30°C). Using atropine, we demonstrated that Gcgr −/− mice have diminished parasympathetic (PNS) influence of the heart at this temperature. Gcgr −/− mice displayed a normal bradycardia as compared to controls in response to administration of either methacholine (to activate the muscarinic acetylcholine receptor) or methoxamine (to activate the baroreflex through agonism of the α1 adrenergic receptor agonist) suggesting that vagal pathways are intact in the Gcgr −/− mice. As OXM is an agonist of the GLP-1 receptor and Gcgr with antidiabetic activity, we suggest OXM may be an alternative to glucagon in the treatment of overdose of beta-blockers to elevate HR in clinical conditions.
Genetic identification of a neural circuit that suppresses appetite
Matthew E. Carter, Marta E. Soden, Larry S. Zweifel & Richard D. Palmiter
Appetite suppression occurs after a meal and in conditions when it is unfavourable to eat, such as during illness or exposure to toxins. A brain region proposed to play a role in appetite suppression is the parabrachial nucleus1, 2, 3, a heterogeneous population of neurons surrounding the superior cerebellar peduncle in the brainstem. The parabrachial nucleus is thought to mediate the suppression of appetite induced by the anorectic hormones amylin and cholecystokinin2, as well as by lithium chloride and lipopolysaccharide, compounds that mimic the effects of toxic foods and bacterial infections, respectively4, 5, 6. Hyperactivity of the parabrachial nucleus is also thought to cause starvation after ablation of orexigenic agouti-related peptide neurons in adult mice1, 7. However, the identities of neurons in the parabrachial nucleus that regulate feeding are unknown, as are the functionally relevant downstream projections. Here we identify calcitonin gene-related peptide-expressing neurons in the outer external lateral subdivision of the parabrachial nucleus that project to the laterocapsular division of the central nucleus of the amygdala as forming a functionally important circuit for suppressing appetite. Using genetically encoded anatomical, optogenetic8 and pharmacogenetic9 tools, we demonstrate that activation of these neurons projecting to the central nucleus of the amygdala suppresses appetite. In contrast, inhibition of these neurons increases food intake in circumstances when mice do not normally eat and prevents starvation in adult mice whose agouti-related peptide neurons are ablated. Taken together, our data demonstrate that this neural circuit from the parabrachial nucleus to the central nucleus of the amygdala mediates appetite suppression in conditions when it is unfavourable to eat. This neural circuit may provide targets for therapeutic intervention to overcome or promote appetite.
The Mathematics of Encryption: An Elementary Introduction
Margaret Cozzens, DIMACS, Rutgers University, Piscataway, NJ, and Steven J. Miller, Williams College, Williamstown, MA
How quickly can you compute the remainder when dividing 10983797 by 120143? Why would you even want to compute this? And what does this have to do with cryptography?
Modern cryptography lies at the intersection of mathematics and computer sciences, involving number theory, algebra, computational complexity, fast algorithms, and even quantum mechanics. Many people think of codes in terms of spies, but in the information age, highly mathematical codes are used every day by almost everyone, whether at the bank ATM, at the grocery checkout, or at the keyboard when you access your email or purchase products online.
This book provides a historical and mathematical tour of cryptography, from classical ciphers to quantum cryptography. The authors introduce just enough mathematics to explore modern encryption methods, with nothing more than basic algebra and some elementary number theory being necessary. Complete expositions are given of the classical ciphers and the attacks on them, along with a detailed description of the famous Enigma system. The public-key system RSA is described, including a complete mathematical proof that it works. Numerous related topics are covered, such as efficiencies of algorithms, detecting and correcting errors, primality testing and digital signatures. The topics and exposition are carefully chosen to highlight mathematical thinking and problem solving. Each chapter ends with a collection of problems, ranging from straightforward applications to more challenging problems that introduce advanced topics. Unlike many books in the field, this book is aimed at a general liberal arts student, but without losing mathematical completeness.
Summer Science Research Poster Session was held in Schow Library on August 2. 54 posters were on display. This was a wonderful opportunity to celebrate and share the collective efforts of 162 summer science research assistants with fellow students, faculty, and visitors. The winners of this year’s informal ‘Great Poster’ competition are in first place, Julia Cline and Willis Kuelthau’s “Evolution of Order in Diblock Copolymer Systems,” in second, Josef Iafrate’s “When Life Gives You Lemons – A Statistical Model for Benford’s Law,” and in third, Tre’ Colbert’s “Acatina Shell Dating: This Thing is Old as Dirt!”
Muzhou Lu ’13 has dedicated three summers and his senior thesis to tracking total solar eclipses to study the Sun’s corona. Lu’s research culminated at this year’s American Astronomical Society (AAS) meeting in Bozeman, Mont. Lu won the Solar Physics Division (SPD) poster competition for his presentation, “Observations and Modeling of Solar Coronal Structures Using High-Resolution Eclipse Images and Space-based Telescopes with Wide Field-of-View.” Co-authors on Lu’s prize-winning poster include Pasachoff, his senior thesis advisor; Daniel B. Seaton ’01, who is now deputy director of a European Space Agency solar spacecraft project; Yingna Su and Aad Van Ballegooijen, Lu’s advisors at the Harvard-Smithsonian Center for Astrophysics; and Royal Observatory of Belgium astronomer Matthew West. “Collaboration is a huge part in any area of research,” Lu says. “I’m glad [Professor Pasachoff] has shown me just what can be achieved through collaboration.”
Lu is spending the summer at Williams, conducting planetarium shows and working with Pasachoff on a journal article based on Lu’s thesis findings. In the fall, Lu will be teaching physics and math, as well as art and rock climbing, at an independent school in Maryland.
Professor Luana Maroja’s article “Partial complementarity of the mimetic yellow bar phenotype in Heliconius butterflies” was recently published in PLOS ONE and is available online at http://dx.plos.org/10.1371/journal.pone.0048627.
The annual Student, Faculty and Staff golf tournament was held on Sunday 21, 2012 at Taconic. The low team score of the day was a 52! The sciences were well represented by Professor Steven Swoap, Administrative Assistant Alicia Romac, Biology major Shelby Shote and general science major Greg Johnson, team score 65. Hank Art and Robert Kavanaugh played too!
October 2012 continued
Assistant professor of Biology, Tim Lebestky contributed to Dispensable, redundant, complementary and cooperative roles of dopamine, octopamine and serotonin in Drosophila melanogaster in The Genetics Society of America. His work investigates the regulation of Drosophila melanogaster behavior by biogenic amines. He and his co-authors examined the broad requirement of the vesicular monoamine transporter (VMAT) for the vesicular storage and exocytotic release of all monoamine neurotransmitters.
Biology Professor Luana Maroja published in EVOLUTION: EDUCATION AND OUTREACH, titled “Where Do I Come From? Using Student’s Mitochondrial DNA to Teach About Phylogeny, Molecular Clocks, and Population Genetics”. She uses this in Biology 305: Evolution. http://www.springerlink.com/content/t43q21224265w423/?MUD=MP
Williams Biology Department: Lois Banta and Derek Dean’s genomics curriculum development project made the cover story for Cell Biology Education-Life Sciences Education.
Cover story link: http://www.lifescied.org/content/11/3.cover-expansion Full article: http://www.lifescied.org/cgi/content/full/11/3/203?etoc
On top of that double dip of authorship, Lois has a second article in the same journal reporting the development and assessment for two bioinformatics modules that she uses in Microbiology
Subaru Outstanding Woman in Science: Phoebe A. Cohen, Assistant Professor of Geosciences, Williams College
The Subaru Outstanding Woman in Science Award will be presented to Phoebe A. Cohen, of the Massachusetts Institute of Technology, for her 2010 Ph.D. research, “Investigations of enigmatic Neoproterozoic eukaryotes,” which is a significant contribution to the fields of paleobiology and geobiology. “In respect to research excellence and accomplishment,” writes nominator Roger E. Summons of the Massachusetts Institute of Technology, Cohen’s work is “characterized by broad geological and paleobiological understanding, fastidious attention to detail in experiment and observation, and an atypical degree of clarity in how her findings are communicated.” Supporting nominator Andrew H. Knoll of Harvard University writes that Cohen’s “broad and deep knowledge will serve her well in a new generation of teaching about our planet’s history.” http://www.geosociety.org/awards/
Ben Iliff ’10 just published a paper with Steve Swoap in the American Journal of Physiology. This manuscript was from his thesis work, for which he shared the David Bruce award for top undergraduate poster at the Experimental Biology meetings in 2010.
Uttara Partap, Williams College, Biology major and Honors student, collaborated with David R Hill, MD, Professor of Medical Sciences, Director of Global Public Health, Frank H. Netter MD, School of Medicine at Quinnipiac University, on two recently published Global Health research papers. Uttara’s interest in Global Health issues started with a Winter Studies course taught at Williams College by Dr. Hill in 2010, “Global Health, Why We Should Care.” Uttara’s final paper was of the highest quality and at Dr. Hill’s urging she continued her research and wrote “The Maoist insurgency (1996–2006) and child health indicators in Nepal,” by Uttara Partapa, David R. Hill, MD in August 2011; it was published in May, 2012 in International Health, a Lancet-affiliated journal (International Health 4 (2012) 135– 142). In addition, Uttara and Dr. Hill published a second paper: “Teaching Global Public Health in the Undergraduate Liberal Arts: A Survey of 50 Colleges,” in The American Society of Tropical Medicine and Hygiene (Am. J. Trop. Med. Hyg., 87(1), 2012, pp. 11–15). This summer, Uttara won a fellowship from the American Physiological Society to work with Steven Swoap, Chair and professor of Biology. Congratulations, Uttara!
Luana S. Maroja, Assistant Professor of Biology, was a contributing participant in this study of adaptive introgression in butterflies. “The phenomenon, known as adaptive introgression, involves different species sharing genetic material and has been considered very rare, especially in animals. Although many species can interbreed in the wild, the resulting hybrids are often infertile and considered an evolutionary dead-end. However, occasionally hybrids might introduce useful genetic material that can help populations adapt to changing conditions. This source of novelty might be more effective than having to wait for a mutation to occur in order to yield a similar result. In the case of butterflies, the effects can be clearly seen on their wings.” Chris Jiggins.
Read the complete paper at: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11041.html
Associate Professor of Computer Science, Morgan McGuire founded the open-access international Journal of Computer Graphics Techniques for scholarly articles on 3D graphics and will serve as its first editor-in-chief. His cofounders on the editorial board span academia and industry, including Google, Harvard University, Pixar, University of Tokyo, and Autodesk. This is an important step towards making scientific knowledge universally available and removing barriers to publication and access. Read their founding letter and journal at http://jcgt.org/ In addition, Morgan McGuire published a new research paper on Scalable Ambient Obscurance with Michael Mara ’12 and David Luebke of NVIDIA Research. SAO is a technique for creating realistic lighting for interactive 3D applications such as video games, medical visualization, and architectural design software. He presented the work at the ACM SIGGRAPH / Eurographics High Performance Graphics conference in Paris, France. http://graphics.cs.williams.edu/papers/SAOHPG12/
by Lisa P. Chu, Steven J. Swoap
Lisa Chu ’10 just published a paper with Steve Swoap in the Journal of Thermal Biology. This manuscript was from her thesis work, for which she shared the David Bruce award for top undergraduate poster at the Experimental Biology meetings in 2010. Williams College, Department of Biology, published in Journal of Thermal Biology, Volume 37, Issue 4, July 2012, Pages 291–296
by Steven J. Swoap, Department of Biology, published in Current Biology, Volume 22, Issue 1, 10 January 2012, Pages R17–R18
Jan 22, 2012
Poster presentations highlight research findings and student-faculty collaborations.
posted June 29, 2011
The Keck Geology Consortium, a national alliance of 18 liberal arts colleges of which Williams College was the founding member, has received a grant of $261,000 to continue its support of intercollegiate collaborative research projects for geosciences undergraduates and faculty for the next year.
posted June 28, 2011
A Williams College team of astronomers, headed by Bryce Babcock and Jay Pasachoff, have been in Hawaii, near Honolulu, to observe a rare double-double event about Pluto.
posted June 22, 2011
Fifty-three members of the Williams College Class of 2011 were awarded associate membership in Sigma Xi, the international scientific honor society, upon graduation in June.
posted May 6, 2011
The National Institute of Standards and Technology, through its Summer Undergraduate Fellowship Program (NIST-SURF), has awarded Williams College a grant to support summer research by David Kealhofer and Christina Knapp, both current sophomores.
posted May 2, 2011
Rob Silversmith ’11 has been awarded a National Science Foundation Graduate Research Fellowship.
posted April 11, 2011
This week, Williams will complete a public art installation by renowned artist Jenny Holzer.
posted March 9, 2011
Antonio Lorenzo ’11 came to Williams serious about science.
posted March 2, 2011
During a research trip to collect botanical data, one of Joan Edwards’ honors students spotted a “poof” in a field of forest flowers that opened up a whole new research avenue for the biology professor.
posted March 2, 2011
When professors encourage undergraduates to start “being scientists” earlyon, says physics professor Tiku Majumder, “we can approach more of a real scientific partnership.”
posted February 24, 2011
The National Science Foundation (NSF) has awarded a three-year grant of $158,234 to Jay Pasachoff.
posted January 14, 2011.
On the recommendation of the Committee on Appointments and Promotions, the Williams College Board of Trustees has promoted seven faculty to the position of associate professor with tenure, effective July 1, 2011. They are Edan Dekel, classics; Sarah Goh, chemistry; Sarah Hammerschlag, religion; Gage McWeeny, English; Bernard Rhie, English; Mihai Stoiciu, mathematics; and Tara Watson, economics.
posted January 7, 2011
Morgan McGuire’s paper on Ambient Occlusion Volumes wins best research paper award at ACM/EuroGraphics High Performance Graphics. Artists have long recognized the importance of soft shadowing effects for the perception of proximity and shape in 3D scenes. Ambient Occlusion is the technical term for this effect.
Frederick Strauch: Publishes Paper “Parallel State Transfer and Efficient Quantum Routing on Quantum Networks”
Posted January 3, 2011
Frederick Strauch, Assistant Professor of Physics, and Chris Chudzicki ’10 published a paper describing a new theoretical analysis of the routing of information in quantum networks.
posted October 29, 2010
Cesar Silva, Hagey Family Professor of Mathematics and department chair at Williams College, was recently awarded a $36,525 grant from the National Science Foundation in support of the Oxtoby Centennial Conference. The project is under the direction of Silva, along with Leslie Chang and Paul Melvin of Bryn Mawr College.
posted October 20, 2010.
Laurie Heatherington, the Edward Dorr Griffin Professor of Psychology at Williams College, was awarded the Distinguished Contribution to Family Systems Research Award along with collaborator Myrna Friedlander of the State University of New York at Albany.
posted October 4, 2010
The National Science Foundation has awarded a grant to support the research of Frederick W. Strauch on “Control and Measurement of Coupled Mesoscopic Quantum Systems.”
posted October 4, 2010
The National Science Foundation has announced the award of a three-year, $285,000 grant to Professor of Physics Protik Majumder.
posted September 29, 2010
Williams College announced 27 members of the Class of 2011 elected into Phi Beta Kappa, the national honor society.
posted July 1, 2010
Kevin Jones, McElfresh Professor of Physics, in collaboration with colleagues at the National Institute of Standards and Technology, published a paper describing a laboratory realization of a near-ideal amplifier for light and a study of its effects on the quantum mechanical state of a pair of light beams.
posted June 29, 2010
Assistant Professor of Mathematics Steven Miller won paper of the year award from the International Journal of Research in Marketing. The paper discusses applying linear programming to movie theatres.
posted June 10, 2010
James Carlton, professor of marine sciences and director of the Williams-Mystic Program, has been appointed to the National Research Council’s Committee on Assessing Numeric Limits for Living Organisms in Ballast Water.