Bio-Med Roundup

This month in Bio-Med Roundup:
  • Dostert et al. provided molecular insights into how airborne pollutants, including asbestos and silica, cause inflammation.
  • O'Neill et al. found that cAMP-depended signaling is a core component of the mammalian circadian pacemaker.
  • Loose et al. and Osawa et al. showed that key proteins involved in bacterial cell division can self organize in vitro.
  • Ghildiyal et al. identified endogenous small interfering RNAs transcribed from both transposons and messenger RNAs in somatic cells of flies.
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CELL/DEVELOPMENTAL BIOLOGY
 
In Vivo Imaging of Membrane-Associated Glycans in Developing Zebrafish (2 May 2008)
S. T. Laughlin, J. M. Baskin, S. L. Amacher, C. R. Bertozzi
Imaging of cell-surface sugars in developing zebrafish reveals dramatic bursts of sugar production in the jaw, olfactory organ, and pectoral fin 60 to 72 hours after fertilization.

Phosphorylation by p38 MAPK as an Alternative Pathway for GSK3β Inactivation (2 May 2008)
T. M. Thornton et al.
A well-studied kinase is shown to be unexpectedly phosphorylated and inhibited by mitogen-activated protein kinase, and this modification activates cell-survival pathways.

Asymmetric Tethering of Flat and Curved Lipid Membranes by a Golgin (2 May 2008)
G. Drin, V. Morello, J.-F. Casella, P. Gounon, B. Antonny
A long protein may tether vesicles to the Golgi apparatus by binding the positively curved vesicle membrane to its N terminus and flat membranes to its C terminus.

Discovery of a Cytokine and Its Receptor by Functional Screening of the Extracellular Proteome (9 May 2008)
H. Lin et al.
A systematic, functional screen of extracellular proteins in yeast identified a previously unknown receptor-ligand pair: the cytokine interleukin-34 and its receptor.

Regulation of the Cellular Heat Shock Response in Caenorhabditis elegans by Thermosensory Neurons (9 May 2008)
V. Prahlad, T. Cornelius, R. I. Morimoto
Activation of a heat-sensitive sensory neuron in the worm Caenorhabditis elegans unexpectedly triggers a heat-shock response throughout the animal.

Design Logic of a Cannabinoid Receptor Signaling Network That Triggers Neurite Outgrowth (16 May 2008)
K. D. Bromberg, A. Ma’ayan, S. R. Neves, R. Iyengar
Analysis of transcription data and known signaling networks predict two previously unrecognized regulators of neuronal growth, which were experimentally confirmed.

The Serine Protease TMPRSS6 Is Required to Sense Iron Deficiency (23 May 2008)
X. Du et al.
A cell-surface enzyme that cleaves proteins is unexpectedly necessary for sensing when iron levels are low and thereby triggering compensatory absorption of iron from food.

A Cytosolic Iron Chaperone That Delivers Iron to Ferritin (30 May 2008)
H. Shi, K. Z. Bencze, T. L. Stemmler, C. C. Philpott
A cytosolic iron-binding protein, PCBP1, carries the reactive but essential element iron to ferritin, its major storage depot in the cell.


BIOCHEMISTRY

Spatial Regulators for Bacterial Cell Division Self-Organize into Surface Waves in Vitro (9 May 2008)
M. Loose, Elisabeth Fischer-Friedrich, Jonas Ries, Karsten Kruse, and Petra Schwille
Two proteins that define the plane of cell division self-organize into waves and spirals on a flat membrane, suggesting that these patterns underlie their function in vivo.
See related Perspective.

Reconstitution of Contractile FtsZ Rings in Liposomes (9 May 2008)
M. Osawa, D. E. Anderson, H. P. Erickson
A tubulin homolog from prokaryotes can, without other proteins, assemble into rings around liposomes and constrict, suggesting a primordial cell division mechanism.
See related Perspective.

Architecture of a Charge-Transfer State Regulating Light Harvesting in a Plant Antenna Protein (9 May 2008)
T. K. Ahn et al.
To protect itself from oxidative damage in bright light, photosystem II operates a tunable shunt that directs excess energy to a yellow accessory pigment that is abundant in corn.

Regulated Protein Denitrosylation by Cytosolic and Mitochondrial Thioredoxins (23 May 2008)
M. Benhar, M. T. Forrester, D. T. Hess, J. S. Stamler
Thioredoxins—known to be antioxidants—also remove nitrosyl groups from a protease to activate it and may also function in this way in other cellular regulatory systems.
See related Perspective.

Surface Tension Transport of Prey by Feeding Shorebirds: The Capillary Ratchet (16 May 2008)
M. Prakash, D. Quéré, J. W. M. Bush
A shorebird moves water droplets containing prey into its throat by repeatedly opening and closing its beak, relying on the physical properties of water to drive the drop upward.
See related Perspective.


IMMUNOLOGY

Innate Immune Activation Through Nalp3 Inflammasome Sensing of Asbestos and Silica (2 May 2008)
C. Dostert et al.
A large multiprotein complex detects particulate airborne pollutants that have been taken up by immune cells in the lung and initiates a potent inflammatory response.
See related Perspective.

A Haptoglobin-Hemoglobin Receptor Conveys Innate Immunity to Trypanosoma brucei in Humans (2 May 2008)
B. Vanhollebeke et al.
A lipoprotein in human blood protects against an African parasite by binding to a parasite receptor and triggering uptake of the lipoprotein, which contains a toxic component.

Coordination of Early Protective Immunity to Viral Infection by Regulatory T Cells (30 May 2008)
J. M. Lund, L. Hsing, T. T. Pham, A. Y. Rudensky
In mice infected with herpes virus, a usually immunosuppressive T cell is necessary for rapid arrival of immune cells and elevated cytokine levels at the site of infection.
See related Perspective.


PHYSIOLOGY

The Energetic Cost of Climbing in Primates (16 May 2008)
J. B. Hanna, D. Schmitt, T. M. Griffin
Large primates expend less energy walking than climbing, but smaller ones walk and climb with similar efficiencies, possibly facilitating an evolutionary shift into trees.

cAMP-Dependent Signaling as a Core Component of the Mammalian Circadian Pacemaker (16 May 2008)
J. S. O’Neill, E. S. Maywood, J. E. Chesham, J. S. Takahashi, M. H. Hastings
Signaling through cyclic adenosine monophosphate determines the amplitude, phase, and period of the mammalian circadian clock and so may be an integral part of the pacemaker.
See related Perspective.

Differential Rescue of Light- and Food-Entrainable Circadian Rhythms (23 May 2008)
P. M. Fuller, J. Lu, C. B. Saper
When hungry, rodents may optimize their chances of finding food by engaging a food-entrained circadian clock in the brain that takes over from the light-driven clock.


NEUROSCIENCE/PSYCHOLOGY
 
A Specialized Forebrain Circuit for Vocal Babbling in the Juvenile Songbird (2 May 2008)
D. Aronov, A. S. Andalman, M. S. Fee
The babbling of young zebra finches learning to sing is produced by a brain region distinct from the adult song center, a pattern that may also apply to other motor systems.

Temperature Sensing by an Olfactory Neuron in a Circuit Controlling Behavior of C. elegans (9 May 2008)
A. Kuhara et al.
An olfactory neuron in Caenorhabditis elegans also senses the ambient temperature and is necessary for worms’ propensity to seek out the temperature at which they were raised.

Early Forebrain Wiring: Genetic Dissection Using Conditional Celsr3 Mutant Mice (16 May 2008)
L. Zhou et al.
A cadherin molecule on the surface of guidepost neurons in the developing brain marks the pathway for axons to follow from the thalamus to the cortex.

The Right and the Good: Distributive Justice and Neural Encoding of Equity and Efficiency (23 May 2008)
M. Hsu, C. Anen, S. R. Quartz
A brain region linked to emotion-processing systems is activated as humans weigh fairness to an individual against benefit for a group.

Predicting Human Brain Activity Associated with the Meanings of Nouns (30 May 2008)
T. M. Mitchell et al.
A model trained to associate specific nouns with resultant images of brain activity can predict what activity pattern will occur when a participant is shown a picture of a new noun.

Log or Linear? Distinct Intuitions of the Number Scale in Western and Amazonian Indigene Cultures (30 May 2008)
S. Dehaene, V. Izard, E. Spelke, P. Pica
Adults from an Amazonian tribe view numbers as a logarithmic progression (e.g., 10 is halfway to 100), suggesting that our linear view of numbers is culturally learned.


MEDICINE

ROS-Generating Mitochondrial DNA Mutations Can Regulate Tumor Cell Metastasis (2 May 2008)
K. Ishikawa et al.
Mutations in mitochondrial DNA that cause enhanced production of reactive oxygen species can increase the propensity of tumor cells to metastasize.

A Polymorphism Within the G6PC2 Gene Is Associated with Fasting Plasma Glucose Levels (23 May 2008)
N. Bouatia-Naji et al.
Variation in a gene for a protein in the pancreas may help explain why people have different levels of fasting blood glucose, a factor that affects disease risk.

MeCP2, a Key Contributor to Neurological Disease, Activates and Represses Transcription (30 May 2008)
M. Chahrour et al.
A transcription factor implicated in autism and learning disorders is unexpectedly found to activate a large number of genes in the hypothalamus, not just a few.
See related Perspective.


MICROBIOLOGY

Phosphorylation of Retinoblastoma Protein by Viral Protein with Cyclin-Dependent Kinase Function (9 May 2008)
A. J. Hume et al.
A human cytomegalovirus protein takes control of the host cell cycle by mimicking a cell cycle kinase that phosphorylates and inactivates a tumor suppressor.

Extending the Sub–Sea-Floor Biosphere (23 May 2008)
E. G. Roussel et al.
Prokaryotic cells and DNA from Archaea are present at depths greater than 1 kilometer in sediments below the ocean floor, where temperatures range up to 100° Celsius.

Virus Population Dynamics and Acquired Virus Resistance in Natural Microbial Communities (23 May 2008)
A. F. Andersson and J. F. Banfield
Fragments of viral genes found within Archaea and Bacteria genomes are part of an antiviral defense system and can be used to identify and track the viruses themselves.

Resource Partitioning and Sympatric Differentiation Among Closely Related Bacterioplankton (23 May 2008)
D. E. Hunt et al.
A model of a marine plankton population reveals that ecologically distinct subgroups undergo sympatric speciation fast enough to overcome horizontal gene flow.


MOLECULAR BIOLOGY

Termination Factor Rho and Its Cofactors NusA and NusG Silence Foreign DNA in E. coli (16 May 2008)
C. J. Cardinale et al.
A known bacterial protein acts broadly to terminate transcription in order to prevent read-through that can accidentally activate cryptic deleterious viruses.

Endogenous siRNAs Derived from Transposons and mRNAs in Drosophila Somatic Cells (23 May 2008)
M. Ghildiyal et al.
Endogenous small interfering RNAs transcribed from both transposons and messenger RNAs are found in somatic cells of flies and may act to silence "selfish" genetic elements.
See related Perspective.

Widespread Translational Inhibition by Plant miRNAs and siRNAs (30 May 2008)
P. Brodersen et al.
Plant microRNAs and small interfering RNAs, thought to inhibit gene expression by cleavage of their RNA targets, also interfere with the translation of these RNAs into protein.

Massive Horizontal Gene Transfer in Bdelloid Rotifers (30 May 2008)
E. A. Gladyshev, M. Meselson, I. R. Arkhipova
Bdelloid rotifers carry a large number of foreign genes—unusual for a metazoan—perhaps explaining how they have escaped extinction despite an asexual life-style.


PLANT SCIENCE

Genome-Scale Proteomics Reveals Arabidopsis thaliana Gene Models and Proteome Dynamics (16 May 2008)
K. Baerenfaller et al.
The Arabidopsis proteome shifts as the plant develops, and proteins not predicted from genome analysis, some derived from introns and pseudogenes, are expressed.

Cell Identity Mediates the Response of Arabidopsis Roots to Abiotic Stress (16 May 2008)
J. R. Dinneny et al.
In Arabidopsis root tips exposed to high salinity or iron deficiency, clusters of genes are induced that are unique to one or both of these stress responses.
See related Perspective.