This month in Bio-Med Roundup:

· Long et al. presented the long-sought crystal structure of a eukaryotic voltage-gated potassium channel.
· Gans et al. reported on the remarkable diversity of soil microbes.
· Longini et al. used a simulation model to analyze possible strategies for containing a newly emergent influenza strain.
· Abe et al. and Wigge et al. described two plant genes that work together to determine the time and location of flowering.


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Jump to:
Neuroscience
Microbiology
Cell/Developmental Biology
Structural Biology
Medicine
Molecular Biology
Plant Science

NEUROSCIENCE

Crystal Structure of a Mammalian Voltage-Dependent Shaker Family K+ Channel (5 August 2005)
S. B. Long, E. B. Campbell, R. MacKinnon
http://www.sciencemag.org/cgi/content/abstract/309/5736/897
Voltage Sensor of Kv1.2: Structural Basis of Electromechanical Coupling (5 August 2005)
S. B. Long, E. B. Campbell, R. MacKinnon
http://www.sciencemag.org/cgi/content/abstract/309/5736/903
An x-ray crystal structure of a eukaryotic voltage-gated potassium channel, probably in its native confirmation, reveals how movement of the voltage sensor triggers opening of the pore.

Hemodynamic Signals Correlate Tightly with Synchronized Gamma Oscillations (5 August 2005)
J. Niessing, B. Ebisch, K. E. Schmidt, M. Niessing, W. Singer, R. A. W. Galuske
In cat visual cortex, brain imaging signals correlate more closely with synchronous synaptic activity than with the rate of action potential firing.
http://www.sciencemag.org/cgi/content/abstract/309/5736/943

Coupling Between Neuronal Firing, Field Potentials, and fMRI in Human Auditory Cortex (5 August 2005)
R. Mukamel, H. Gelbard, A. Arieli, U. Hasson, I. Fried, R. Malach
When a subject is viewing and listening to a movie, brain imaging of the auditory cortex provides a good indication of the underlying neuronal activity.
http://www.sciencemag.org/cgi/content/abstract/309/5736/951

MICROBIOLOGY

Protein Structures Forming the Shell of Primitive Bacterial Organelles (5 August 2005)
C. A. Kerfeld, M. R. Sawaya, S. Tanaka, C. V. Nguyen, M. Phillips, M. Beeby, T. O. Yeates
The carboxysome, a CO2-fixing microcompartment in certain bacteria, resembles a viral capsid of hexameric, protein building blocks, with pores that may regulate metabolite flow.
http://www.sciencemag.org/cgi/content/abstract/309/5736/936

Export-Mediated Assembly of Mycobacterial Glycoproteins Parallels Eukaryotic Pathways (5 August 2005)
B. C. VanderVen, J. D. Harder, D. C. Crick, J. T. Belisle
In bacteria, sugar residues are added to proteins during export by a mechanism similar to that used by eukaryotes.
http://www.sciencemag.org/cgi/content/abstract/309/5736/941

In Situ Stable Isotope Probing of Methanogenic Archaea in the Rice Rhizosphere (12 August 2005)
Y. Lu and R. Conrad
An Archaean microbe in anoxic soils of rice paddies produces much of the atmospheric greenhouse gas methane that results from human activities.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1088

Complete Genome Sequence and Lytic Phase Transcription Profile of a Coccolithovirus (12 August 2005)
W. H. Wilson, D. C. Schroeder, M. J. Allen, M. T. G. Holden, J. Parkhill, B. G. Barrell, C. Churcher, N. Hamlin, K. Mungall, H. Norbertczak et al.
A large virus that infects marine algae unexpectedly harbors genes for apoptosis and transcription, thought to be absent from viruses.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1090

Contact-Dependent Inhibition of Growth in Escherichia coli (19 August 2005)
S. K. Aoki, R. Pamma, A. D. Hernday, J. E. Bickham, B. A. Braaten, D. A. Low
Showing unexpected interaction, some individual E. coli produce a large protein that inhibits the growth of other E. coli when they are in contact.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1245

Genome-Wide RNAi Screen for Host Factors Required for Intracellular Bacterial Infection (19 August 2005)
H. Agaisse, L. S. Burrack, J. A. Philips, E. J. Rubin, N. Perrimon, D. E. Higgins
http://www.sciencemag.org/cgi/content/abstract/309/5738/1248
Drosophila RNAi Screen Reveals CD36 Family Member Required for Mycobacterial Infection (19 August 2005)
J. A. Philips, E. J. Rubin, N. Perrimon
http://www.sciencemag.org/cgi/content/abstract/309/5738/1251
An RNAi screen identifies host proteins required for infection by two different bacteria, and a comparison identifies general and microbe-specific factors.

Genome Streamlining in a Cosmopolitan Oceanic Bacterium (19 August 2005)
S. J. Giovannoni, H. J. Tripp, S. Givan, M. Podar, K. L. Vergin, D. Baptista, L. Bibbs, J. Eads, T. H. Richardson, M. Noordewier et al.
A marine bacterium has a miniscule genome, free of junk DNA, probably because its huge population size allows selection against the small fitness cost of replicating nonfunctional DNA.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1242

Molecular Mechanism for Switching of P. falciparum Invasion Pathways into Human Erythrocytes (26 August 2005)
J. Stubbs, K. M. Simpson, T. Triglia, D. Plouffe, C. J. Tonkin, M. T. Duraisingh, A. G. Maier, E. A. Winzeler, A. F. Cowman
A newly described gene encoding a very large protein allows the malaria parasite to switch the receptor it uses for red blood cell infection, which helps in evading host defenses.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1384

Computational Improvements Reveal Great Bacterial Diversity and High Metal Toxicity in Soil (26 August 2005)
J. Gans, M. Wolinsky, J. Dunbar
Analysis of DNA diversity reveals that many soils contain 100 times more species of microbes than previously thought, most of them rare.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1387
See related Perspective at http://www.sciencemag.org/cgi/content/summary/309/5739/1331

CELL/DEVELOPMENTAL BIOLOGY

Stem Cell Depletion Through Epidermal Deletion of Rac1 (5 August 2005)
S. A. Benitah, M. Frye, M. Glogauer, F. M. Watt
A small GTP-binding regulatory protein is required for maintaining stem cells in the skin and preventing their differentiation into other epidermal cell types.
http://www.sciencemag.org/cgi/content/abstract/309/5736/933
See related Perspective at http://www.sciencemag.org/cgi/content/summary/309/5736/890

Direct Control of Germline Stem Cell Division and Cyst Growth by Neural Insulin in Drosophila (12 August 2005)
L. LaFever and D. Drummond-Barbosa
Insulin-like peptides in the brain signal nutrient availability, directly regulating the division of germline stem cells, thus coordinating resource availability and reproduction.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1071

TAZ, a Transcriptional Modulator of Mesenchymal Stem Cell Differentiation (12 August 2005)
J.-H. Hong, E. S. Hwang, M. T. McManus, A. Amsterdam, Y. Tian, R. Kalmukova, E. Mueller, T. Benjamin, B. M. Spiegelman, P. A. Sharp, et al.
A regulatory protein binds to transcription factors via a four–amino acid domain, directing stem cells to become bone cells while inhibiting their differentiation into fat cells.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1074

Formation of Regulatory Patterns During Signal Propagation in a Mammalian Cellular Network (12 August 2005)
A. Ma’ayan, S. L. Jenkins, S. Neves, A. Hasseldine, E. Grace, B. Dubin-Thaler, N. J. Eungdamrong, G. Weng, P. T. Ram, J. J. Rice et al.
A network in hippocampal neurons having 545 components with 1259 interactions suggests how cells may process information to allow transient or stable responses.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1078

Nuclear Reprogramming of Somatic Cells After Fusion with Human Embryonic Stem Cells (26 August 2005)
C. A. Cowan, J. Atienza, D. A. Melton, K. Eggan
Nuclei from adult human cells can be reprogrammed to an embryonic state by insertion into embryonic stem cells, potentially providing a source of new stem cells.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1369

Spatial Coordination of Spindle Assembly by Chromosome-Mediated Signaling Gradients (26 August 2005)
M. Caudron, G. Bunt, P. Bastiaens, E. Karsenti
Chromosomes produce gradients of activated regulators that determine the spatial organization and assembly of the mitotic spindle.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1373
See related Perspective at http://www.sciencemag.org/cgi/content/summary/309/5739/1334

Toll-Like Receptor 8–Mediated Reversal of CD4+ Regulatory T Cell Function (26 August 2005)
G. Peng, Z. Guo, Y. Kiniwa, K. Voo, W. Peng, T. Fu, D. Y. Wang, Y. Li, H. Y. Wang, R.-F. Wang
Cells of the adaptive immune system that suppress potentially damaging immune responses unexpectedly are regulated by a receptor of the innate immune system.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1380

STRUCTURAL BIOLOGY

Structural Basis for the Activation of Cholera Toxin by Human ARF6-GTP (12 August 2005)
C. J. O’Neal, M. G. Jobling, R. K. Holmes, W. G. J. Hol
Cholera toxin hijacks a human G protein during infection, activating it by causing conformational changes that open the active site to substrates.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1093

Structure of a Synaptic gd Resolvase Tetramer Covalently Linked to Two Cleaved DNAs (19 August 2005)
W. Li, S. Kamtekar, Y. Xiong, G. J. Sarkis, N. D. F. Grindley, T. A. Steitz
During chromosomal recombination, two subunits of the tetrameric resolvase rotate 180 degrees to reposition the DNA ends for strand exchange.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1210

Nitrogenase Complexes: Multiple Docking Sites for a Nucleotide Switch Protein (26 August 2005)
F. A. Tezcan, J. T. Kaiser, D. Mustafi, M. Y.Walton, J. B. Howard, D. C. Rees
The nitrogenase protein complex reduces dinitrogen to ammonia by electron transfer between its subunits, switched on and off by the hydrolysis of ATP.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1377

MEDICINE

Regulation of Blood Glucose by Hypothalamic Pyruvate Metabolism (5 August 2005)
T. K. T. Lam, R. Gutierrez-Juarez, A. Pocai, L. Rossetti
A region at the base of the brain functions as the body’s glucose monitor, instructing the liver to shut down glucose production when blood glucose levels get too high. http://www.sciencemag.org/cgi/content/abstract/309/5736/943

 Containing Pandemic Influenza at the Source (12 August 2005)
I. M. Longini Jr., A. Nizam, S. Xu, K. Ungchusak, W. Hanshaoworakul, D. A. T. Cummings, M. E. Halloran
A model of a southeast Asian population predicts that a hypothetical emergent flu strain may be containable with antiviral agents, quarantine, and prevaccination.
http://www.sciencemag.org/cgi/content/abstract/309/5737/1083

Highly Pathogenic H5N1 Influenza Virus Infection in Migratory Birds (19 August 2005)
J. Liu, H. Xiao, F. Lei, Q. Zhu, K. Qin, X.-w. Zhang, X.-l. Zhang, D. Zhao, G. Wang, Y. Feng et al.
During May 2005, an outbreak of avian influenza decimated birds at a major breeding site for migratory waterfowl in central China.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1206

Mitogenic Influence of Human R-Spondin1 on the Intestinal Epithelium (19 August 2005)
K.-A. Kim, M. Kakitani, J. Zhao, T. Oshima, T. Tang, M. Binnerts, Y. Liu, B. Boyle, E. Park, P. Emtage et al.
A newly described human growth factor that causes dramatic growth of the cells that line the intestine may be useful in counteracting some side effects of chemotherapy.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1256

MOLECULAR BIOLOGY

Rewiring of the Yeast Transcriptional Network Through the Evolution of Motif Usage (5 August 2005)
J. Ihmels, S. Bergmann, M. Gerami-Nejad, I. Yanai, M. McClellan, J. Berman, N. Barkai
Yeast species that grow aerobically have a common sequence in the promoters of mitochondrial ribosomal proteins, apparently acquired by a common ancestor.
http://www.sciencemag.org/cgi/content/abstract/309/5736/938

Effects of Telomerase and Telomere Length on Epidermal Stem Cell Behavior (19 August 2005)
I. Flores, M. L. Cayuela, M. A. Blasco
Telomeres, structures at chromosome ends, can regulate the mobilization of stem cells, possibly contributing to their effects on aging and cancer.
http://www.sciencemag.org/cgi/content/abstract/309/5738/1255

Circadian Clock Control by SUMOylation of BMAL1 (26 August 2005)
L. Cardone, J. Hirayama, F. Giordano, T. Tamaru, J. J. Palvimo, P. Sassone-Corsi
The addition of a small regulatory peptide to a transcription factor component of the circadian clock is required for its own rhythmic expression and is controlled by another clock component.
http://www.sciencemag.org/cgi/content/abstract/309/5739/1390

PLANT SCIENCE

Antagonistic Control of Disease Resistance Protein Stability in the Plant Immune System (5 August 2005)
B. F. Holt III, Y. Belkhadir, J. L. Dangl
Two plant proteins thought to trigger protective pathways upon pathogen attack actually form a regulatory system that keeps defense proteins available for rapid deployment.
http://www.sciencemag.org/cgi/content/abstract/309/5736/929

FD, a bZIP Protein Mediating Signals from the Floral Pathway Integrator FT at the Shoot Apex (12 August 2005)
M. Abe, Y. Kobayashi, S. Yamamoto, Y. Daimon, A. Yamaguchi, Y. Ikeda, H. Ichinoki, M. Notaguchi, K. Goto, T. Araki
http://www.sciencemag.org/cgi/content/abstract/309/5737/1052
Integration of Spatial and Temporal Information During Floral Induction in Arabidopsis (12 August 2005)
P. A. Wigge, M. C. Kim, K. E. Jaeger, W. Busch, M. Schmid, J. U. Lohmann, D. Weigel
http://www.sciencemag.org/cgi/content/abstract/309/5737/1056
Two nuclear genes, one activated in the leaf and one in the shoot, work together to determine the time and location of flowering.
See related Perspective at http://www.sciencemag.org/cgi/content/summary/309/5737/1024


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