The active site and the phospholipid activation of rat liver lysosomal lipase are not stereospecific

The stereochemical specificity of lysosomal lipase of rat liver was investigated using enantiomeric triacylglycerol analogs, sn-1-alkyl-2,3-diacylglycerol and sn-3-alkyl-1,2-diacylglycerol as substrates. Lysosomal lipase utilized both substrates with equal rates. The dependence of the activity of lysosomal lipase on the stereoconfiguration of activating acidic phospholipid was also studied. Our results showed that both sn-3-phospholipids (diphosphatidylglycerol, phosphatidylserine) and sn-1-phospholipids (bis(monoacylglycero)phosphate (BMP) were efficient activators of this enzyme and thus the stereochemical configuration of the activating phospholipid is not important. Accordingly, the rat liver lysosomal lipase lacks stereospecificity with respect to both the triacylglycerol substrate and the acidic phospholipid activator.     

Population and community level responses in Anas -species to patch disturbance caused by an ecosystem engineer, the beaver

We studied the response of a guild of three Anas -species, to patch disturbance caused by the beaver Castor canadensis in southern Finland during 1988–1996 Of the three species, the teal Anas crecca increased in beaver ponds during the first two years of beaver occupation compared to the situation before the beaver The mallard Anas platyrhynchos and wigeon Anas penelope did not respond to beaver flooding during the first two years Also dominance relations changed upon inundation The mallard usually was more numerous than the teal before the beaver, but the reverse was the case during beaver occupation The study shows that some animal guilds may benefit from disturbance although species dominance relations may change And, that this change in dominance can be caused by an ecosystem engineer, the beaver