Effect of acute administration of high doses of ethanol on the canalicular Na+K+ dependent ATPASE in the isolated and perfused rat liver

Na+-K+-ATPase in canaliculi-enriched liver plasma membranes was found to be inhibited by high concentration of ethanol (12 mmoles %ml) both in vitro and in vivo; the decrease of Na+-K+-ATPase, which is considered a major factor in the production of bile-salt independent fraction of canalicular bile flow, may be the cause of the previously observed reduction of bile flow after ethanol administration.     

Polyglutamine expansion in huntingtin increases its insertion into lipid bilayers

An expanded polyglutamine (Q) tract (>37Q) in huntingtin (htt) causes Huntington disease. Htt associates with membranes and polyglutamine expansion in htt may alter membrane function in Huntington disease through a mechanism that is not known. Here we used differential scanning calorimetry to examine the effects of polyQ expansion in htt on its insertion into lipid bilayers. We prepared synthetic lipid vesicles composed of phosphatidylcholine and phosphatidylethanolamine and tested interactions of htt amino acids 1-89 with 20Q, 32Q or 53Q with the vesicles. GST-htt1-89 with 53Q inserted into synthetic lipid vesicles significantly more than GST-htt1-89 with 20Q or 32Q. We speculate that by inserting more into cell membranes, mutant huntingtin could increase disorder within the lipid bilayer and thereby disturb cellular membrane function.     

Purification of sialic acid binding protein from saprophytic bacteria by hydrophobic-interaction chromatography on butyl-toyopearl and polymer-coated porous glass

Summary Two rigid sorbents with identical nominal hydrophobic functions (Butyl-Toyopearl and poly(N-butylacrylamide)-coated porous glass (Butyl-WPG)) were compared upon chromatographic purification of lectin from Bacillus subtilis. Hydrophobic-interaction chromatography on the Butyl-WPG promotes the better resolution of nonactive contaminants from the active lectin. There were found optimal conditions for HPLC-analysis of purified lectin preparations. One step of chromatography on the butyl-WPG provided a considerable purification of lectin (98% of contaminants were removed), which retained 62,5% of its initial hemagglutinating activity.     

Kinetics of uranous iron and ferrous iron oxidation by thiobacillus ferrooxidans

Archives of Microbiology -     

Exercise-induced changes of Factor VIII complex in healthy subjects and in type-I diabetics: relation between growth hormone and Von Willebrand Factor increments

This work aims to study the exercise-induced changes of Factor VIII Complex both in healthy subjects and in type I diabetics without vascular complications, and to investigate the possible relations between growth hormone and Von Willebrand's Factor response to exercise. Results show that maximal exercise performed by cycle ergometer causes a significant increment of the procoagulant subunit (VIII:C) and of Von Willebrand Factor (VIII:RiCoF) both in healthy controls and in type I diabetics, whereas a slight increment of Factor VIII-Related antigen (VIIIR:Ag) is observed only in diabetics. The shape of the mean GH response to exercise parallels the one of Von Willebrand's Factor: however, the presence of VIII:RiCoF increments also in GH non-responders supports the conclusion that growth hormone is not the only factor involved in the regulation of Von Willebrand's Factor exercise-induced increase.     

Identification of the genetic locus responsible for non-polar root induction by Agrobacterium rhizogenes 1855

Summary Root proliferation can be induced by Agrobacterium rhizogenes on carrot discs both on the apical and basal surface (facing the root apex and base, respectively) or on the apical surface only, depending on the bacterial strain. This differential response on the two surfaces is denominated polarity. We correlate the polarity of some strains with the absence of an Ri plasmid genetic locus, present in non polar strains such as A. rhizogenes 1855, which bears sequence homology with the auxin genes of Ti plasmid T-DNA. We demonstrate that this locus is responsible for root induction on the basal surface since insertion of a transposon in this region of pRi1855 induces polarity in this strain.     

Delayed numerical response of goshawks to population fluctuations of forest grouse

Delayed density-dependent mortality induced by delayed numerical response of predators can drive prey populations to fluctuate in high-amplitude cycles. We studied numerical response of goshawks Accipiter gentilis to varying densities of their main prey (forest grouse) in western Finland during 1979–1996. Occupancy rate of goshawk territories tracked grouse numbers with a two year lag. Occupancy rate of goshawk territories and pooled number of adult and young goshawks correlated negatively with a 1–2 year lag to the chick production of grouse. Goshawk to grouse ratio was negatively related to grouse density. This suggests that goshawk predation on grouse is inversely dependent on grouse density. We conclude that in northern Europe with few alternative preys, goshawk predation might contribute to the generation of multiannual cycles of forest grouse. This should be tested experimentally.