Chemo- and stereoselective reduction of an alpha-cyanoketone by bakers' yeast at low temperature.

[formula: see text] The bakers' yeast mediated reduction of 3-oxo-3-phenylpropanenitrile (1) proceeds at 4 degrees C to give exclusively (S)-3-hydroxy-3-phenylpropanenitrile (3) in 59% yield. This is in contrast to the corresponding reaction at room temperature which yields a mixture of reduction and alkylation products. This work demonstrates the use of low temperature to improve yeast selectivity.

Changes in uterine endometrial phospholipids and fatty acids throughout the oestrous cycle and early pregnancy in the ewe.

This study examined changes in ovine endometrial phospholipids and fatty acid concentrations associated with luteolysis and the establishment of pregnancy in the ewe on days 3, 12 and 15, respectively. Results from this study indicate that endometrial lipids increased as the oestrous cycle progressed from days 3 to 12 and 15, whereas during early pregnancy, endometrial lipids decreased on day 15 of pregnancy when compared to days 3 and 12 of pregnancy. Phosphatidylcholine followed a similar pattern to that of total lipids, with an increase in phosphatidylcholine concentrations as the oestrous cycle progressed. During the early stages of pregnancy, phosphatidylcholine increased from day 3 to day 12, but then returned to previous levels by day 15 of pregnancy. Phosphatidylethanolamine increased late in the oestrous cycle, on day 15 as compared to days 3 and 12. This increase did not occur during early pregnancy, with phosphatidylethanolamine concentrations being constant from day 3 to day 15 of pregnancy. Both phosphatidylinositol and phosphatidylserine followed a similar pattern to phosphatidylethanolamine during the oestrous cycle and remained constant during early pregnancy. The fatty acid content of the major phospholipids involved in prostaglandin synthesis were examined over the range of fatty acids from C14:0 to C24:1omega9. Although changes in arachidonic acid were observed, there were no clear indications that these changes were directly related to the changes in PGF2alpha synthesis.

Positional distribution of acyl and alk-1-enyl groups in grey and white matter ethanolamine and choline phosphoglycerides of a marsupial, the koala (Phascolarctos cinereus).

The major phosphoglycerides in grey and white matter from the brain of the koala have been separated and examined. The major polyunsaturated fatty acids present in both the diacyl- and alk-1-enyl acylglycerophosphorylethanolamines from grey matter were 22:6 omega 3, 20:4 omega 6, and 22:4 omega 6. In both grey and white matter, 22:6 omega 3 and 20:4 omega 6 were concentrated in the 2-position of diacylglycerophosphorylethanolamines and 22:4 omega 6 in the 2-position of alk-1-enylacylglycerophosphorylethanolamines; polyunsaturated fatty acid levels were higher in diacylglycerophosphorylethanolamines. Ethanolamine phosphoglyceride fractions from grey matter were enriched in polyunsaturated fatty acids compared with those from white matter. The acyl groups 18:0, 18:1, and 16:0 and their alk-1-enyl analogues were prominent in grey and white matter ethanolamine phosphoglycerides; 18:1 was dominant in white matter alk-1-enylacylglycerophosphorylethanolamines. The plasmalogen composition of ethanolamine phosphoglycerides was 55% in grey matter and 76% in white matter. Choline phosphoglycerides contained negligible plasmalogen and low polyunsaturated fatty acid levels. Diacylglycerophosphorylcholine was characterized by high levels of 16:0 and 18:1. Similar acyl group distributions were estimated in the 1-position in both grey and white matter, 16:0 being present at greater than 50%. The presence of the molecular species 18:0/22:6 omega 3 was indicated in grey matter diacylglycerophosphorylethanolamine, 18:1/18:1 in white matter alk-1-enylcylglycerophosphorylethanolamine, and 16:0/18:1 in white matter diacylglycerophosphorylcholine.