Evolution. Enhanced: A rodent as big as a buffalo

The largest living rodent is the South American capybara, a creature the size of a sheep that unlike smaller rodents stands on relatively straight legs. However, as Alexander explains in his Perspective, a new fossil find in Venezuela (Sánchez-Villagra et al.) reveals that the capybara would be dwarfed by Phoberomys, a giant rodent the size of a buffalo that lived during the Miocene Epoch.     

NMR imaging of catalytic hydrogenation in microreactors with the use of para-hydrogen

Catalysis is vital to industrial chemistry, and the optimization of catalytic reactors attracts considerable resources. It has proven challenging to correlate the active regions in heterogeneous catalyst beds with morphology and to monitor multistep reactions within the bed. We demonstrate techniques, using magnetic resonance imaging and para-hydrogen (p-H2) polarization, that allow direct visualization of gas-phase flow and the density of active catalyst in a packed-bed microreactor, as well as control over the dynamics of the polarized state in space and time to facilitate the study of subsequent reactions. These procedures are suitable for characterizing reactors and reactions in microfluidic devices where low sensitivity of conventional magnetic resonance would otherwise be the limiting factor.     

A predator unmasked: life cycle of Bdellovibrio bacteriovorus from a genomic perspective

Predatory bacteria remain molecularly enigmatic, despite their presence in many microbial communities. Here we report the complete genome of Bdellovibrio bacteriovorus HD100, a predatory Gram-negative bacterium that invades and consumes other Gram-negative bacteria. Its surprisingly large genome shows no evidence of recent gene transfer from its prey. A plethora of paralogous gene families coding for enzymes, such as hydrolases and transporters, are used throughout the life cycle of B. bacteriovorus for prey entry, prey killing, and the uptake of complex molecules.     

Gene interaction at HLA-DQ enhances autoantibody production in primary Sj?gren's syndrome

Primary Sj?gren's syndrome is an autoimmune disorder characterized by dryness of the mouth and eyes. The human leukocyte antigen (HLA) locus DQ is related to the primary Sj?gren's syndrome autoantibodies that bind the RNA proteins Ro/SSA and La/SSB. Both DQ1 and DQ2 alleles are associated with high concentrations of these autoantibodies. An analysis of all possible combinations at DQ has shown that the entire effect was due to heterozygotes expressing the DQ1 and DQ2 alleles. These data suggest that gene interaction between DQ1 and DQ2 (or alleles at associated loci), possibly from gene complementation of trans-associated surface molecules, influences the autoimmune response in primary Sj?gren's syndrome.     

Erythropoiesis in the rat: differential rates of DNA synthesis and cell proliferation

Direct in vivo estimates of DNA synthesis time in early and late erythroblasts were obtained by using the H(3)- and C(14)-thymidine double-la-beling technique. A double-emulsion autoradiographic procedure was used to resolve the two isotopes. Early erythroblasts were found to proliferate at a rate about five times that of late cells. This results primarily from a shorter mean DNA synthesis time in early cells (2.5 hours) than in late cells (6.5 hours).     

Argon-40-argon-39 dating of apollo sample 15555

An age of 3.33+/-0.05x10(9) years was obtained for Apollo 15 sample 15555 by argon40-argon-39 dating. The age of rock 15555, a basalt from the rim of Hadley Rille, establishes an upper limit to the age of the rille. The basalt flows filling the Hadley Rille section of the Imbrium basin postdate the formation of the basin-as measured by the Apollo 14 samples of the Fra Mauro formation-by at least 500x10(6) years. Therefore, the mare basalts cannot be simple impact melts but rather must result from some igneous activity on the moon.     

The global circulation of seasonal influenza A (H3N2) viruses

Antigenic and genetic analysis of the hemagglutinin of approximately 13,000 human influenza A (H3N2) viruses from six continents during 2002-2007 revealed that there was continuous circulation in east and Southeast Asia (E-SE Asia) via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year. Seed strains generally first reached Oceania, North America, and Europe, and later South America. This evidence suggests that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution. If the trends observed during this period are an accurate representation of overall patterns of spread, then the antigenic characteristics of A (H3N2) viruses outside E-SE Asia may be forecast each year based on surveillance within E-SE Asia, with consequent improvements to vaccine strain selection.