This month in Bio-Med Roundup:

• D'Costa et al . found that soil-dwelling bacteria constitute a vast reservoir of antibiotic resistance.
• Biek et al. demonstrated that a fast-evolving virus can be used to track the population dynamics of its wildlife host.
• Svenningsson et al. identified a new link between depression, serotonin, and a brain protein called p11.
• Park et al . showed that an enzyme with completely new function can be created by mimicking natural evolutionary processes that both alter and preserve protein architecture.
  
  Jump to:
  Cell Biology
  Microbiology
  Plant Science
  Genetics/Genomics
  Molecular Biology
  Biochemistry
  Psychology/Sociology
  Neuroscience

CELL BIOLOGY

A Clonogenic Bone Marrow Progenitor Specific for Macrophages and Dendritic Cells ( 6 January 2006 )
D. K. Fogg, C. Sibon, C. Miled, S. Jung, P. Aucouturier, D. R. Littman, A. Cumano, F. Geissmann
One bone marrow cell type is the precursor for two key immune cells, both of which process foreign antigens.
http://www.sciencemag.org/cgi/content/abstract/311/5757/83

PER-TIM Interactions in Living Drosophila Cells: An Interval Timer for the Circadian Clock ( 13 January 2006 )
P. Meyer, L. Saez, M. W. Young
Two components of the circadian clock move independently into the nucleus rather than together as a complex, calling into question the current model of the clock.
http://www.sciencemag.org/cgi/content/abstract/311/5758/226
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5758/184

Herpesviral Protein Networks and Their Interaction with the Human Proteome ( 13 January 2006 )
P. Uetz, Y.-A. Dong, C. Zeretzke, C. Atzler, A. Baiker, B. Berger, S. V. Rajagopala, M. Roupelieva, D. Rose, E. Fossum, J. Haas
Upon infection of a host cell, the protein interaction networks of herpesviruses change so that they more closely resemble those of the host cells.
http://www.sciencemag.org/cgi/content/abstract/311/5758/239
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5758/187

Chromosomes Can Congress to the Metaphase Plate Before Biorientation ( 20 January 2006 )
T. M. Kapoor, M. A. Lampson, P. Hergert, L. Cameron, D. Cimini, E. D. Salmon, B. F. McEwen, A. Khodjakov
During mitosis, duplicated chromosomes pulled by a fiber toward one pole of the cell move back to the middle by hitching a ride on a fiber of an already-positioned chromosome set.
http://www.sciencemag.org/cgi/content/abstract/311/5759/388
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5759/343

Vaccinia Virus–Induced Cell Motility Requires F11L-Mediated Inhibition of RhoA Signaling ( 20 January 2006 )
F. Valderrama, J. V. Cordeiro, S. Schleich , F. Frischknecht, M. Wa y
Vaccinia virus causes infected cells to migrate and alters their adhesion properties by rearranging the actin cytoskeleton.
http://www.sciencemag.org/cgi/content/abstract/311/5759/377

MICROBIOLOGY

Magnetosomes Are Cell Membrane Invaginations Organized by the Actin-Like Protein MamK ( 13 January 2006 )
A. Komeili, Z. Li, D. K. Newman, G. J. Jensen

Bacteria that sense magnetic fields arrange their magnetite-containing membrane invaginations along cytoskeleton-like tracks.
http://www.sciencemag.org/cgi/content/abstract/311/5758/242

Long-Term Transmission of Defective RNA Viruses in Humans and Aedes Mosquitoes ( 13 January 2006 )
J. Aaskov, K. Buzacott, H. M. Thu, K. Lowry, E. C. Holmes
An inactive, defective form of the dengue fever virus appropriates proteins from normal viruses to replicate and is maintained through generations of infection and transmission.
http://www.sciencemag.org/cgi/content/abstract/311/5758/236

South-Seeking Magnetotactic Bacteria in the Northern Hemisphere ( 20 January 2006 )
S. L. Simmons, D. A. Bazylinski, K. J. Edwards
It has been assumed that marine bacteria in the northern hemisphere all swim toward magnetic north, but blooms of south-seeking ones are actually mixed in.
http://www.sciencemag.org/cgi/content/abstract/311/5759/371

Sampling the Antibiotic Resistome ( 20 January 2006 )
V. M. D'Costa, K. M. McGrann, D. W. Hughes, G. D. Wright
Of 480 bacterial strains isolated from diverse soil samples, each was resistant to at least seven antibiotics and some to as many as 20.
http://www.sciencemag.org/cgi/content/abstract/311/5759/374
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5759/342

PLANT SCIENCE

Integration of Plant Responses to Environmentally Activated Phytohormonal Signals ( 6 January 2006 )
P. Achard, H. Cheng, L. De Grauwe, J. Decat, H. Schoutteten, T. Moritz, D. Van Der Straeten, J. Peng, N. P. Harberd
Stunted plant growth due to environmental stress is not just a byproduct of diminished nutrients but is rather an adaptive response that helps the plant survive.
http://www.sciencemag.org/cgi/content/abstract/311/5757/91

Cytokinin Signaling and Its Inhibitor AHP6 Regulate Cell Fate During Vascular Development ( 6 January 2006 )
A. P. Mähönen, A. Bishopp, M. Higuchi, K. M. Nieminen, K. Kinoshita, K. Törmäkangas, Y. Ikeda, A. Oka, T. Kakimoto, Y. Helariutta
A disabled enzyme blocks hormone signaling in regions of a growing flowering plant, resulting in the development of vessels that carry water and minerals upward.
http://www.sciencemag.org/cgi/content/abstract/311/5757/94

A Bacterial Inhibitor of Host Programmed Cell Death Defenses Is an E3 Ubiquitin Ligase ( 13 January 2006 )
R. Janjusevic, R. B. Abramovitch, G. B. Martin, C. E. Stebbins
During infection, pathogenic bacteria mimic and interpolate with biochemical pathways of the host plant.
http://www.sciencemag.org/cgi/content/abstract/311/5758/222

A Molecular Framework for Plant Regeneration ( 20 January 2006 )
J. Xu, H. Hofhuis, R. Heidstra, M. Sauer, J. Friml, B. Scheres
After a plant is wounded, flow of a growth factor in plant roots is disrupted, causing differentiation of cells that then redirect the growth factor to trigger regeneration.
http://www.sciencemag.org/cgi/content/abstract/311/5759/385

GENETICS/GENOMICS

Metagenomics to Paleogenomics: Large-Scale Sequencing of Mammoth DNA ( 20 January 2006 )
H. N. Poinar, C. Schwarz, J. Qi, B. Shapiro, R. D. E. MacPhee, B. Buigues, A. Tikhonov, D. H. Huson, L. P. Tomsho, A. Auch et al.
Recovery and sequencing of large amounts of mitochondrial and nuclear DNA from an 18,000-year-old mammoth support the evolution of mammoths from elephants about 6 million years ago.
http://www.sciencemag.org/cgi/content/abstract/311/5759/392

A Virus Reveals Population Structure and Recent Demographic History of Its Carnivore Host ( 27 January 2006 )
R. Biek, A. J. Drummond, M. Poss
An innocuous virus carried by cats shows that recent cougar populations result from the expansion and merging of small isolated populations that had been reduced by hunting.
http://www.sciencemag.org/cgi/content/abstract/311/5760/538

Community Genomics Among Stratified Microbial Assemblages in the Ocean's Interior ( 27 January 2006 )
E. F. DeLong, C. M. Preston, T. Mincer, V. Rich, S. J. Hallam, N.-U. Frigaard, A. Martinez, M. B. Sullivan, R. Edwards, B. Rodriguez Brito et al.
Community genomic analysis indicates that the microbes near the surface of the Northern Pacific are mobile and photosynthetic, while those below 200 meters have pili and synthesize polysaccharides and antibiotics.
http://www.sciencemag.org/cgi/content/abstract/311/5760/496

MOLECULAR BIOLOGY

Structural Basis for Double-Stranded RNA Processing by Dicer ( 13 January 2006 )
I. J. MacRae, K. Zhou, F. Li, A. Repic, A. N. Brooks, W. Z. Cande, P. D. Adams, J. A. Doudna
The RNA binding site of the small RNA–generating enzyme Dicer is located 65 Å from the two RNA cleavage sites, reliably producing ~25-nucleotide RNA fragments.
http://www.sciencemag.org/cgi/content/abstract/311/5758/195

The snoRNA HBII-52 Regulates Alternative Splicing of the Serotonin Receptor 2C ( 13 January 2006 ) S. Kishore and S. Stamm
An exon is included in the mature messenger RNA of a receptor only when a small RNA inhibits a silencer sequence in the precursor RNA.
http://www.sciencemag.org/cgi/content/abstract/311/5758/230

Methylation of tRNAAsp by the DNA Methyltransferase Homolog Dnmt2 ( 20 January 2006 )
M. G. Goll, F. Kirpekar, K. A. Maggert, J. A. Yoder, C.-L. Hsieh, X. Zhang, K. G. Golic, S. E. Jacobsen, T. H. Bestor
A methyltransferase widely thought to add methyl groups to DNA actually covalently methylates transfer RNA.
http://www.sciencemag.org/cgi/content/abstract/311/5759/395

BIOCHEMISTRY

An Architectural Framework That May Lie at the Core of the Postsynaptic Density ( 27 January 2006 )
M. K. Baron, T. M. Boeckers, B. Vaida, S. Faham , M. Gingery, M. R. Sawaya, D. Salyer, E. D. Gundelfinger, J. U. Bowie
A scaffolding protein, assisted by bound Zn 2+ , can assemble into large sheets and may form a platform for the construction of the postsynaptic density.
http://www.sciencemag.org/cgi/content/abstract/311/5760/531

Design and Evolution of New Catalytic Activity with an Existing Protein Scaffold ( 27 January 2006 )
H.-S. Park , S.-H. Nam, J. K. Lee, C. N. Yoon, B. Mannervik, S. J. Benkovic, H.-S. Kim
A process that mimics natural protein evolution converts an enzyme in the metallohydrolase superfamily into a new family member with a different catalytic function.
http://www.sciencemag.org/cgi/content/abstract/311/5760/535
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5760/475

PSYCHOLOGY/SOCIOLOGY

Core Knowledge of Geometry in an Amazonian Indigene Group ( 20 January 2006 )
S. Dehaene, V. Izard, P. Pica, E. Spelke
Children and adults of an indigenous group from Amazonia use geometrical concepts despite the lack of specific words to describe them.
http://www.sciencemag.org/cgi/content/abstract/311/5759/381

Empirical Analysis of an Evolving Social Network ( 6 January 2006 )
G. Kossinets and D. J. Watts
Tracking e-mail interactions among members of a large university community for a year reveals the dynamics of social network behavior in this setting.
http://www.sciencemag.org/cgi/content/abstract/311/5757/88

NEUROSCIENCE

Alterations in 5-HT1B Receptor Function by p11 in Depression-Like States ( 6 January 2006 )
P. Svenningsson, K. Chergui, I. Rachleff, M. Flajolet, X. Zhang, M. El Yacoubi, J.-M. Vaugeois, G. G. Nomikos, P. Greengard
A brain protein required for the proper function of serotonin receptors is decreased in brains of depressed animals and patients but can be increased by antidepressant drugs.
http://www.sciencemag.org/cgi/content/abstract/311/5757/77
See related Perspective at http://www.sciencemag.org/cgi/content/summary/311/5757/45

Excitatory Effect of GABAergic Axo-Axonic Cells in Cortical Microcircuits ( 13 January 2006 )
J. Szabadics, C. Varga, G. Molnár, S. Oláh, P. Barzó, G. Tamás
A classic inhibitory neurotransmitter unexpectedly excites axons of cortical neurons, activating local networks.
http://www.sciencemag.org/cgi/content/abstract/311/5758/233

The Cellular Basis of a Corollary Discharge ( 27 January 2006 )
J. F. A. Poulet and B. Hedwig
Crickets "know" when they hear their own song because the neural circuit for singing sends a corollary discharge to auditory neurons as well as to the motor circuit for singing.
http://www.sciencemag.org/cgi/content/abstract/311/5760/518