• Genetics
• Plant Science
• Molecular Biology
• Structural Biology/Biochemistry
• Medicine
• Neuroscience
• Microbiology
• Cell/Developmental Biology
• Immunology
  

This month’s BioMed Roundup is sponsored by:

Reproducibility in Protein Biomarker Research Webinar brought to you by Science
"Tackling Reproducibility Issues in Mass Spectrometry–based Biomarker Discovery"
December 5, 2007, at 12 noon Eastern Time (9am PT, 5pm GMT):
What factors should you consider in the design of your mass spectrometry–based proteomics experiments?  Three experts will present their thoughts and discuss best practices for study design, including challenges you might encounter and how to overcome them.  Questions can be submitted live to the expert panel.
Time is running out!  Register today  ( www.sciencemag.org/webinar ) 
Produced by the Science/AAAS Business Office and sponsored by Bio-Rad.

GENETICS
 
Genetic Effects of Captive Breeding Cause a Rapid, Cumulative Fitness Decline in the Wild (5 October 2007)
H. Araki, B. Cooper, M. S. Blouin
Steelhead trout bred in captivity and then released reproduced poorly in comparison to wild fish; these rapid negative effects may prevent use of captive fish for repopulation.

The Chlamydomonas Genome Reveals the Evolution of Key Animal and Plant Functions (12 October 2007)
S. S. Merchant, S. E. Prochnik, O. Vallon, E. H. Harris, S. J. Karpowicz, G. B. Witman, A. Terry, A. Salamov, L. K. Fritz-Laylin, L. Maréchal-Drouard et al.
The genome of a single-celled green alga encodes photosynthetic enzymes like those in green plants, such animal-like features as cilia and flagella.

A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder (12 October 2007)
D. L. Cox-Foster, S. Conlan, E. C. Holmes, G. Palacios, J. D. Evans, N. A. Moran, P. Quan, T. Briese, M. Hornig, D. M. Geiser et al.
A comparative genomic approach suggests that a virus may be contributing to the current devastation of domesticated bee colonies.

Functional Divergence of Former Alleles in an Ancient Asexual Invertebrate (12 October 2007)
N. N. Pouchkina-Stantcheva, B. M. McGee, C. Boschetti, D. Tolleter, S. Chakrabortee, A. V. Popova, F. Meersman, D. Macherel, D. K. Hincha, A. Tunnacliffe
A rotifer that only reproduces asexually preserves genetic diversity through gene duplication followed by functional divergence of the alleles.
See related Perspective.

Mitochondrial DNA as a Genomic Jigsaw Puzzle (19 October 2007)
W. Marande and G. Burger
The mitochondrial genes of the unicellular eukaryote Diplonema are fragmented among many small chromosomes, and their coding RNAs are pieced together to form messenger RNAs.
See related Perspective.

Paired-End Mapping Reveals Extensive Structural Variation in the Human Genome (19 October 2007)
J. O. Korbel, A. E. Urban, J. P. Affourtit, B. Godwin, F. Grubert, J. F. Simons, P. M. Kim, D. Palejev, N. J. Carriero, L. Du et al.
Sequencing of structure variations over segments of DNA from two individuals of different ethnic groups showed unexpected levels of diversity.

Wasp Gene Expression Supports an Evolutionary Link Between Maternal Behavior and Eusociality (19 October 2007)
A. L. Toth, K. Varala, T. C. Newman, F. E. Miguez, S. K. Hutchison, D. A. Willoughby, J. F. Simons, M. Egholm, J. H. Hunt, M. E. Hudson, G. E. Robinson
Analysis of a set of genes expressed in the brain of a primitive wasp shows that the care shown by worker wasps toward siblings probably evolved from maternal care behavior.



PLANT SCIENCE
Odor-Mediated Push-Pull Pollination in Cycads (5 October 2007)
I. Terry, G. H. Walter, C. Moore, R. Roemer, C. Hull
To ensure pollination of female plants, male Australian cycads periodically heat up, volatilizing a toxic chemical that repels resident beetle pollinators.

Methyl Salicylate Is a Critical Mobile Signal for Plant Systemic Acquired Resistance (5 October 2007)
S.-W. Park, E. Kaimoyo, D. Kumar, S. Mosher, D. F. Klessig
In response to viral infection, tobacco plants locally produce methyl salicylate, which then spreads and renders the whole plant more resistant to subsequent infections.

FKF1 and GIGANTEA Complex Formation Is Required for Day-Length Measurement in Arabidopsis (12 October 2007)
M. Sawa, D. A. Nusinow, S. A. Kay, T. Imaizumi
Flowering is triggered only when both light and enough of a particular protein are available in the afternoon, conditions only satisfied during longer days of spring.
See related Perspective.

Lyso-Phosphatidylcholine Is a Signal in the Arbuscular Mycorrhizal Symbiosis (12 October 2007)
D. Drissner, G. Kunze, N. Callewaert, P. Gehrig, M. Tamasloukht, T. Boller, G. Felix, N. Amrhein, M. Bucher
Lysophospholipids made in the roots of tomato and potato plants, which grow in association with mycorrhizal fungi, induce genes for phosphate transfer in the fungi.

Trojan Horse Strategy in Agrobacterium Transformation: Abusing MAPK Defense Signaling (19 October 2007)
A. Djamei, A. Pitzschke, H. Nakagami, I. Rajh, H. Hirt
A bacterial plant pathogen co-opts one of the plant’s own defense proteins to facilitate transfer of its infectious DNA into the nucleus.

Changes in Regulation of a Transcription Factor Lead to Autogamy in Cultivated Tomatoes (26 October 2007)
K.-Y. Chen, B. Cong, R. Wing, J. Vrebalov, S. D. Tanksley
Unlike their ancestors, domesticated tomatoes self-fertilize because a cell elongation mutation causes short styles, burying these female reproductive parts among male anthers.

Plant Pathogen Recognition Mediated by Promoter Activation of the Pepper Bs3 Resistance Gene (26 October 2007)
P. Römer, S. Hahn, T. Jordan, T. Strauß, U. Bonas, T. Lahaye
A Bacterial Effector Acts as a Plant Transcription Factor and Induces a Cell Size Regulator (26 October 2007)
S. Kay, S. Hahn, E. Marois, G. Hause, U. Bonas
In pepper plants, a protein from a bacterial pathogen acts as a transcription factor that both elongates cells, the characteristic sign of infection, and induces a defensive response.



MOLECULAR BIOLOGY
Widespread Role for the Flowering-Time Regulators FCA and FPA in RNA-Mediated Chromatin Silencing (5 October 2007)
I. Bäurle, L. Smith, D. C. Baulcombe, C. Dean
Two proteins known to participate in flowering are also required for chromatin silencing at various genetic loci early in Arabidopsis development.

JMJD6 Is a Histone Arginine Demethylase (19 October 2007)
B. Chang, Y. Chen, Y. Zhao, R. K. Bruick
An enzyme is discovered that removes methyl groups from arginines in histone proteins, which together with DNA form the bulk of chromatin and help regulate gene expression.
See related Perspective.

Demethylation of H3K27 Regulates Polycomb Recruitment and H2A Ubiquitination (19 October 2007)
M. G. Lee, R. Villa, P. Trojer, J. Norman, K.-P. Yan, D. Reinberg, L. Di Croce, R. Shiekhattar
An enzyme is described that removes methyl groups from a lysine in a human histone protein, a modification thought to help regulate gene expression.
See related Perspective.

Permuted tRNA Genes Expressed via a Circular RNA Intermediate in Cyanidioschyzon merolae (19 October 2007)
A. Soma, A. Onodera, J. Sugahara, A. Kanai, N. Yachie, M. Tomita, F. Kawamura, Y. Sekine
RNA transcribed from split, noncontiguous transfer RNA genes in red algae is circularized, joining the discontinuous segments and allowing processing into mature transfer RNA.
See related Perspective.

Structure of a NHEJ Polymerase–Mediated DNA Synaptic Complex (19 October 2007)
N. C. Brissett, R. S. Pitcher, R. Juarez, A. J. Picher, A. J. Green, T.R. Dafforn, G. C. Fox, L. Blanco, A. J. Doherty
Broken, nonhomologous prokaryotic DNA is repaired by a DNA polymerase that enables each end to search for complementarity on the opposing end.



STRUCTURAL BIOLOGY/BIOCHEMISTRY
 
PKA Type IIα Holoenzyme Reveals a Combinatorial Strategy for Isoform Diversity (12 October 2007)
J. Wu, S. H. J. Brown, S. von Daake, S. S. Taylor
The structure of the catalytic subunit of cyclic AMP–dependent protein kinase bound to a regulatory subunit reveals how this enzyme activates two different signaling pathways.

Fluorescence-Force Spectroscopy Maps Two-Dimensional Reaction Landscape of the Holliday Junction (12 October 2007)
S. Hohng, R. Zhou, M. K. Nahas, J. Yu, K. Schulten, D. M. J. Lilley, T. Ha
Small forces like those encountered in living cells can cause measurable, nanometer-scale conformational changes in a four-stranded DNA structure formed during recombination.

Structure of Hexameric DnaB Helicase and Its Complex with a Domain of DnaG Primase (19 October 2007)
S. Bailey, W. K. Eliason, T. A. Steitz
The structures of the two enzymes that initiate replication on single-stranded DNA show that one stimulates the other by stabilizing it as a hexamer in an activated conformation.

Nanomechanical Basis of Selective Gating by the Nuclear Pore Complex (26 October 2007)
R. Y. H. Lim, B. Fahrenkrog, J. Köser, K. Schwarz-Herion, J. Deng, U. Aebi
Regulators of nuclear permeability reversibly collapse parts of nuclear pore proteins, a process that may underlie control of nuclear transport in cells.



MEDICINE
 
A Neuroligin-3 Mutation Implicated in Autism Increases Inhibitory Synaptic Transmission in Mice (5 October 2007)
K. Tabuchi, J. Blundell, M. R. Etherton, R. E. Hammer, X. Liu, C. M. Powell, T. C. Südhof
A mouse model reveals that a mutation that changes the balance of excitatory and inhibitory synapses affects learning skills, a finding that may help understand autism.
See related Perspective.

Coactivation of Receptor Tyrosine Kinases Affects the Response of Tumor Cells to Targeted Therapies (12 October 2007)
J. M. Stommel, A. C. Kimmelman, H. Ying, R. Nabioullin, A. H. Ponugoti, R. Wiedemeyer, A. H. Stegh, J. E. Bradner, K. L. Ligon, C. Brennan et al.
In glioblastoma cancer cells, drugs that work by inhibiting receptor tyrosine kinases are more powerful in combination than when administered alone.



NEUROSCIENCE

Glia Promote Local Synaptogenesis Through UNC-6 (Netrin) Signaling in C. elegans (5 October 2007)
D. A. Colón-Ramos, M. A. Margeta, K. Shen
Glial cells can orchestrate neuron-to-neuron connections by attracting processes from the postsynaptic cell and triggering synapse formation in the presynaptic cell.

Inactivation of the Interoceptive Insula Disrupts Drug Craving and Malaise Induced by Lithium (26 October 2007)
M. Contreras, F. Ceric, F. Torrealba
The insula, a part of the brain that monitors the emotional and internal state of the body, is required for drug addiction, possibly functioning to detect the negative aspects of withdrawal.

Chimpanzees Are Rational Maximizers in an Ultimatum Game (5 October 2007)
K. Jensen, J. Call, M. Tomasello
In a game of fairness, chimpanzees act only to maximize their own benefits, whereas human toddlers also value social norms like cooperation and parity.



MICROBIOLOGY
 
Microbial Population Structures in the Deep Marine Biosphere (5 October 2007)
J. A. Huber, D. B. M. Welch, H. G. Morrison, S. M. Huse, P. R. Neal, D. A. Butterfield, M. L. Sogin
Rapid sequencing of microbial populations shows differences in archaeal diversity between two deep sea vents, but fails to provide a full inventory of the bacterial population.

A Linear Pentapeptide Is a Quorum-Sensing Factor Required for mazEF-Mediated Cell Death in Escherichia coli (26 October 2007)
I. Kolodkin-Gal, R. Hazan, A. Gaathon, S. Carmeli, H. Engelberg-Kulka
A small peptide mediates programmed cell death in a bacterial population, offseting starvation, clearing a toxin, or halting the spread of a viral infection.
See related Perspective.



CELL/DEVELOPMENTAL BIOLOGY
 
Target Protectors Reveal Dampening and Balancing of Nodal Agonist and Antagonist by miR-430 (12 October 2007)
W.-Y. Choi, A. J. Giraldez, A. F. Schier
A novel technology to disrupt miRNA-mRNA interactions reveals that some miRNAs may repress antagonistic developmental regulators.

Network Analysis of Oncogenic Ras Activation in Cancer (19 October 2007)
E. C. Stites, P. C. Trampont, Z. Ma, K. S. Ravichandran
A model of cell signaling reveals why only one mutated form of an oncogene occurs in tumors and suggests a strategy for selective inhibition of oncogene-containing cells.



IMMUNOLOGY
 
In Situ Imaging of the Endogenous CD8 T Cell Response to Infection (5 October 2007)
K. M. Khanna, J. T. McNamara, L. Lefrançois
Imaging of the spleen during bacterial infection reveals where immune cell percursors divide and are activated by antigens, and how they migrate through channels to the blood.

This month’s BioMed Roundup is sponsored by:

Reproducibility in Protein Biomarker Research Webinar brought to you by Science
"Tackling Reproducibility Issues in Mass Spectrometry–based Biomarker Discovery"
December 5, 2007, at 12 noon Eastern Time (9am PT, 5pm GMT):
What factors should you consider in the design of your mass spectrometry–based proteomics experiments?  Three experts will present their thoughts and discuss best practices for study design, including challenges you might encounter and how to overcome them.  Questions can be submitted live to the expert panel.
Time is running out!  Register today  ( www.sciencemag.org/webinar ) 
Produced by the Science/AAAS Business Office and sponsored by Bio-Rad.