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Full-Text Articles in Life Sciences

Deep-Sea Origin And In-Situ Diversification Of Chrysogorgiid Octocorals, Catherine S. Mcfadden, Eric Pante, Scott C. France, Arnaud Couloux, Corinne Cruaud, Sarah Samadi, Les Watling Jan 2012

Deep-Sea Origin And In-Situ Diversification Of Chrysogorgiid Octocorals, Catherine S. Mcfadden, Eric Pante, Scott C. France, Arnaud Couloux, Corinne Cruaud, Sarah Samadi, Les Watling

All HMC Faculty Publications and Research

The diversity, ubiquity and prevalence in deep waters of the octocoral family Chrysogorgiidae Verrill, 1883 make it noteworthy as a model system to study radiation and diversification in the deep sea. Here we provide the first comprehensive phylogenetic analysis of the Chrysogorgiidae, and compare phylogeny and depth distribution. Phylogenetic relationships among 10 of 14 currently-described Chrysogorgiidae genera were inferred based on mitochondrial (mtMutS, cox1) and nuclear (18S) markers. Bathymetric distribution was estimated from multiple sources, including museum records, a literature review, and our own sampling records (985 stations, 2345 specimens). Genetic analyses suggest that the Chrysogorgiidae as currently described is …


How Muscles Function - The Work Loop Technique, Anna N. Ahn Jan 2012

How Muscles Function - The Work Loop Technique, Anna N. Ahn

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Anna Ahn discusses Bob Josephson’s 1985 paper entitled: ‘Mechanical power output from striated muscle during cyclic contraction’.


Escherichia Coli Lacking Rpos Are Rare In Natural Populations Of Non-Pathogens, Emily Snyder '11, David M. Gordon, Daniel M. Stoebel Jan 2012

Escherichia Coli Lacking Rpos Are Rare In Natural Populations Of Non-Pathogens, Emily Snyder '11, David M. Gordon, Daniel M. Stoebel

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The alternative sigma factor RpoS controls a large regulon that allows E. coli to respond to a variety of stresses. Mutations in rpoS can increase rates of nutrient acquisition at the cost of a decrease in stress resistance. These kinds of mutations evolve rapidly under certain laboratory conditions where nutrient acquisition is especially challenging. The frequency of strains lacking RpoS in natural populations of E. coli is less clear. Such strains have been found at frequencies over 20% in some collections of wild isolates. However, laboratory handling can select for RpoS-null strains and may have affected some of these strain …