Relative biological activity of certain prostaglandins and their enantiomers.

A series of mirror image (ent) forms of prostaglandins F2 and E2 have been compared for potency in a hamster antifertility test. In the PGF2 series, ent-compounds surveyed had less potency than corresponding natural structures. For the PGE2 series, 11alpha-(15S)-ent-PGE2 methyl ester was 10-fold more potent than PGE2. Altering the C-9 hydroxy configuration in the PGF2 series from the natural alpha to beta decreased potency dramatically for compounds tested.     

Regulation of the synthesis of the third component of complement and factor B in cord blood monocytes by lipopolysaccharide

We compared the regulation of C3 and factor B synthesis in cord blood and adult monocytes by using techniques for identification and quantification of newly synthesized proteins, lipopolysaccharide (LPS) from several Gram-negative organisms, and precursors of LPS. Synthesis of C3 and factor B in cord blood monocytes was unaffected by lipid A (the active moiety of LPS extracted by the Westphal procedure). In contrast, adult monocytes increased C3 synthesis by 11.5-fold and factor B synthesis by 3.1-fold in response to LPS. This difference in cord blood monocyte response to LPS was specific in that other LPS-induced monocyte functions (superoxide production and phagocytosis) were stimulated comparably in both cord blood and adult monocytes by LPS. To characterize further this regulatory difference, the roles of LPS precursors, arachidonic acid metabolites, and of factor(s) released by adult monocytes were examined. Precursors of the lipid portion of LPS (lipid X and lipid Y), LPS isolated by trichloroacetic acid extraction, and endotoxin-associated protein (EAP) increased C3 and factor B synthesis in cord blood monocytes. Inhibitors of the lipoxygenase pathway (dexamethasone, ETYA) but not of the cyclooxygenase pathway (indomethacin) abrogated the response of adult monocytes to lipid A and EAP and of cord blood monocytes to EAP. Finally, co-incubation of adult monocytes and cord blood monocytes in LPS-containing medium resulted in enhancement of C3 and factor B synthesis in cord blood monocytes. These data suggest that the difference in LPS response between cord blood and adult monocytes may result from differences in lipid processing or protein recognition of LPS, differences in the production of lipoxygenase pathway products, and/or one or more regulatory factors. The availability of human mononuclear phagocytes which exhibit distinct differences in biosynthetic responsiveness to LPS should permit investigation of the molecular mechanism(s) by which LPS affects C3 and factor B gene expression.     

Comparison of microbial communities in pilot-scale bioreactors treating Bayer liquor organic wastes

Western Australian bauxite deposits are naturally associated with high amounts of humic and fulvic materials that co-digest during Bayer processing. Sodium oxalate remains soluble and can co-precipitate with aluminium hydroxide unless it is removed. Removal of sodium oxalate requires a secondary crystallisation step followed by storage. Bioreactors treating oxalate wastes have been developed as economically and environmentally viable treatment alternatives but the microbial ecology and physiology of these treatment processes are poorly understood. Analysis of samples obtained from two pilot-scale moving bed biofilm reactors (MBBRs) and one aerobic suspended growth bioreactor (ASGB) using polymerase chain reaction- denaturing gradient gel electrophoresis of 16S rRNA genes showed that members of the α-, β- and γ-Proteobacteria subgroups were prominent in all three processes. Despite differing operating conditions, the composition of the microbial communities in the three reactors was conserved. MBBR2 was the only configuration that showed complete degradation of oxalate from the influent and the ASGB had the highest degradation rate of all three configurations. Several strains of the genus Halomonas were isolated from the bioreactors and their morphology and physiology was also determined.     

Operation Everest II: muscle energetics during maximal exhaustive exercise

To investigate the metabolic basis for the reduction in peak blood lactate concentration that occurs with maximal exercise after acclimatization to altitude, eight male subjects [maximal O2 uptake of 51.2 +/- 3.0 (SE) ml.kg-1.min-1] were acclimated to progressive hypobaria over a 40-day period. Before decompression (SL-1), at 380 and 282 Torr, and on return to sea level (SL-2) the subjects performed progressive cycle exercise to exhaustion. Analysis of muscle samples obtained from the vastus lateralis before exercise and at exhaustion indicated a pronounced reduction (P less than 0.05) in muscle lactate concentration (mmol/kg dry wt) at 282 Torr (39.2 +/- 11) compared with SL-1 (113 +/- 9.7), 380 Torr (94.6 +/- 18), and SL-2 (92.7 +/- 22). For the other glycolytic intermediates studied (glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, and pyruvate) only the increase in glucose 1-phosphate, glucose 6-phosphate, and fructose 6-phosphate were blunted (P less than 0.05) at 282 Torr. The reduction in muscle glycogen concentration during exercise was similar (P less than 0.05) for all environmental conditions. Although exercise resulted in reductions (P less than 0.05) in ATP and creatine phosphate averaging 30 and 51%, respectively, the magnitude of the change was not dependent on the degree of hypobaria. Inosine monophosphate was elevated (P less than 0.05) approximately 11-fold with exercise at both SL-1 and SL-2. These findings support the hypothesis that the lower lactate concentration observed at 282 Torr after exhaustive exercise is due to a reduction in anaerobic glycolysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Production of recombinant human serum albumin from Saccharomyces cerevisiae

Human serum albumin has been constitutively expressed in a Saccharomyces cerevisiae brewing yeast. After cell growth and disruption the product was associated with the insoluble fraction and represented approximately 1% of total cell protein. After the cell debris was extensively washed, the albumin was solubilized with 8 M urea and 28 mM 2-mercaptoethanol in 50 mM sodium carbonate buffer, pH 10. The denatured albumin was refolded by dialysis and further purified by anion exchange and gel filtration chromatography. Losses of renatured material could be reduced, or higher protein concentrations used during refolding, if the denatured product was purified by cation-exchange chromatography in urea prior to refolding. Apart from an additional N-terminal N-acetyl methionine, the refolded product proved identical to human serum albumin derived from plasma when compared by a variety of physical, chemical, and biological analytical methods.