Electrophoretic heterogeneity and age-related change of serine proteinase fromAspergillus sojae

Five forms of serine proteinase (EC 3.4.21.14) have been purified fromAspergillus sojae. This paper reports heterogeneity of electrophoretic mobilities, isoelectric points, and kinetic parameters of multiple forms of serine proteinase fromAspergillus sojae, including agerelated changes in thek _cat /K _m of electrophoretic species.     

Molecular and enzymatic properties of 1,2-α-d-mannosidase fromAspergillus saitoi

The molecular properties, such as molecular weight, N-and C-terminal amino acids, amino acid composition, and circular dichroism, of 1,2--mannosidase isolated from the culture filtrate ofAspergillus saitoi were determined.The enzyme had aK _m of 0.67 mM andk _cat of 1.27/s with mannobiose at pH 50.0 and 30°C. The anomeric configuration of the reaction products of the enzyme was examined by studying the -anomer. A single Manl2Man linkage in intact Taka-amylase A fromAspergillus oryzae was hydrolyzed, producing free mannose.     

Inhibition of brain prostaglandin D synthetase and prostaglandin D2 dehydrogenase by some saturated and unsaturated fatty acids

The activities of rat brain prostaglandin D synthetase and swine brain prostaglandin D2 dehydrogenase were inhibited by some saturated and unsaturated fatty acids. Myristic acid was most potent among saturated straight-chain fatty acids so far tested. The IC50 values of this acid were 80 microM for prostaglandin D synthetase and 7 microM for prostaglandin D2 dehydrogenase, respectively. Little inhibition was found with methyl myristate and myristyl alcohol. The IC50 values of these derivatives were more than 200 microM for both enzymes, suggesting that the free carboxyl group was essential for the inhibition. The effects of cis double bond structure of fatty acids on the inhibition potency were examined by the use of the carbon 18 and 20 fatty acids. The inhibition potencies for both enzymes increased with the number of cis double bonds; the IC50 values of stearic, oleic, linoleic and linolenic acid were, respectively, more than 200, 60, 30 and 30 microM for prostaglandin D synthetase, and 20, 10, 8.5 and 7 microM for prostaglandin D2 dehydrogenase. Arachidonic acid also inhibited the activities of both enzymes with respective IC50 values of 40 microM for prostaglandin D synthetase and 3.9 microM for prostaglandin D2 dehydrogenase, while arachidic acid showed little inhibition. The kinetic studies with myristic acid and arachidonic acid demonstrated that the inhibition by these fatty acids was competitive and reversible for both enzymes. Myristic acid and other fatty acids also inhibited the activities of several enzymes in prostaglandin metabolism, although to a lesser extent. The IC50 values of myristic acid for prostaglandin E isomerase, thromboxane synthetase and NAD-linked prostaglandin dehydrogenase (type I) were 200, 700 and 100 microM, respectively. However, this fatty acid showed little inhibition on fatty acid cyclooxygenase (20% at 800 microM), glutathione-requiring prostaglandin D synthetase from rat spleen (20% at 800 microM), and NADP-linked prostaglandin dehydrogenase (type II) (no inhibition at 200 microM).     

Wound healing in the cornea of the chick embryo

Spatio-temporal changes in the shapes of the epithelial cells in culture were followed with the aid of scanning electron microscopy. On a substratum that enables the epithelium to spread extensively, the first remarkable change in shapes of the cells occurred at the margin of epithelium at 12 h of culture. The marginal cells formed leading edges with filo- or lamellipodia, flattened, and lost microvilli on surface. In accordance with those changes, the borderlines among cells became almost indiscrenible. Flattening of the cells was the essential characteristic associated with active epithelial spreading throughout the culture period. Elongation of cells of intermediate zone at right angles to the direction of the locomotion of the marginal cells at 24 h of culture was the second significant change. As the third, the change from the ordinary pentagonal or hexagonal to extraordinary tetragonal or other polygonal shapes, with or without irregular margins, began in cells of the intermediate area at 24 h and propagated to those in inner area. The active deformation of the inner cells with no space in which to move was considered to play some role in the extensive epithelial spreading.     

A possible discrepancy between the exposed and the whole population depending on range-size and trap-spacing in vole populations

Population Ecology - From a field study for the vole population (Clethrionomys rufocanus) in Hokkaido in the late summer of 1965, it has been proved that the range length may decrease from 25 to 18...