Effect of the phase state of lipids on their interaction with cobra cytotoxin

Interaction between cytotoxin of the Central Asia cobra venom and dimiristoylphosphatidylcholine bilayer depending on its phase state was studied by ESR with spin label. A conclusion can be drawn that the efficiency of cytotoxin effect on the membranes depends on their phase state. Cytotoxin molecules are incorporated into myophile region of the bilayer, only if the latter is in the liquid crystal state. The interaction between cytotoxins and lipids of the bilayer in a gel state is in the main conditioned by electrostatic forces.     

3-Hydroxyanthranilic acid metabolism. IV. Spectrophotometric evidence for the formation of an intermediate

Evidence has been presented for the formation of an intermediate compound in the metabolism of 3-hydroxyanthranilic acid to quinolinic acid by 3-hydroxyanthranilase from rat liver preparations. The production of the intermediate was demonstrated by spectrophotometric analyses and quinolinic acid measurements of incubation mixtures in which small amounts of acetone powder extracts of rat liver were used as the enzyme source. The calculated extinction coefficient of the compound was more than double that of the substrate or of the final product, quinolinic acid.The intermediate was shown to be an oxidation product of 3-hydroxyanthranilate as indicated by Thunberg experiments. The data obtained indicate that the intermediate may be a quinone-type compound.     

A climate for contemporary evolution

A new study of divergence in freshwater fish provides strong evidence of rapid, temperature-mediated adaptation. This study is particularly important in the ongoing debate over the extent and significance of evolutionary response to climate change because divergence has occurred in relatively few generations in spite of ongoing gene flow and in the aftermath of a significant genetic bottleneck, factors that have previously been considered obstacles to evolution. Climate change may thus be more likely to foster contemporary evolutionary responses than has been anticipated, and I argue here for the importance of investigating their possible occurrence.