The subzero microbiome: microbial activity in frozen and thawing soils.

Most of the Earth's biosphere is characterized by low temperatures (<5°C) and cold-adapted microorganisms are widespread. These psychrophiles have evolved a complex range of adaptations of all cellular constituents to counteract the potentially deleterious effects of low kinetic energy environments and the freezing of water. Microbial life continues into the subzero temperature range, and this activity contributes to carbon and nitrogen flux in and out of ecosystems, ultimately affecting global processes.

Uptake of dissolved organic carbon by gammaproteobacterial subgroups in coastal waters of the West Antarctic Peninsula.

Heterotrophic bacteria are well known to be key players in the turnover of dissolved organic material (DOM) in the oceans, but the relationship between DOM uptake and bacterial clades is still not well understood. Here we explore the turnover and single-cell use of glucose, an amino acid mixture, N-acetylglucosamine (NAG), and protein by gammaproteobacterial clades in coastal waters of the West Antarctic Peninsula in summer and fall. More than 60% of the cells within two closely related gammaproteobacterial clades, Ant4D3 and Arctic96B-16, were active in using the amino acid mixture, protein, and NAG.

Growth activity of gammaproteobacterial subgroups in waters off the west Antarctic Peninsula in summer and fall.

Characterizing both growth and abundance is important in understanding the role of bacterial communities in biogeochemical cycling of global oceans. However, these two quantities are seldom measured together for specific bacterial clades. Our goal was to examine growth and abundance of three gammaproteobacterial subgroups, including SAR86, at the single-cell level by microautoradiography combined with fluorescence in situ hybridization (FISH) in coastal waters of the west Antarctic Peninsula region during two austral summers and one austral fall.

Innate immune response of human alveolar macrophages during influenza A infection.

Alveolar macrophages (AM) are one of the key cell types for initiating inflammatory and immune responses to influenza virus in the lung. However, the genome-wide changes in response to influenza infection in AM have not been defined. We performed gene profiling of human AM in response to H1N1 influenza A virus PR/8 using Affymetrix HG-U133 Plus 2.

Abundance and single-cell activity of heterotrophic bacterial groups in the western Arctic Ocean in summer and winter.

Environmental conditions in the western Arctic Ocean range from constant light and nutrient depletion in summer to complete darkness and sea ice cover in winter. This seasonal environmental variation is likely to have an effect on the use of dissolved organic matter (DOM) by heterotrophic bacteria in surface water. However, this effect is not well studied and we know little about the activity of specific bacterial clades in the surface oceans.

Innate immune response to influenza A virus in differentiated human alveolar type II cells.

Alveolar Type II (ATII) cells are important targets for seasonal and pandemic influenza. To investigate the influenza-induced innate immune response in those cells, we measured the global gene expression profile of highly differentiated ATII cells infected with the influenza A virus at a multiplicity of infection of 0.5 at 4 hours and 24 hours after inoculation.

Seasonal protein changes support rapid energy production in hibernator brainstem.

During the torpor phase of mammalian hibernation when core body temperature is near 4 degrees C, the autonomic system continues to maintain respiration, blood pressure and heartbeat despite drastic reductions in brain activity. In addition, the hibernator's neuronal tissues enter into a protected state in which the potential for ischemia-reperfusion injury is markedly minimized. Evolutionary adaptations for continued function and neuroprotection throughout cycles of torpor and euthermia in winter are predicted to manifest themselves partly in changes in the brainstem proteome.