Synthesis of 6(α,β)-aminocholestanols as ergosterol biosynthesis inhibitors

Δ⁷-5-Desaturase catalyses one of the last steps in ergosterol biosynthesis in fungi. Moreover Δ⁵-unsaturation is necessary for the sparking function. Synthesis of three pairs of C-6 epimeric cholestanol derivatives are described as potential growth inhibitors. Preliminary results suggest that 6β-aminocholestanol is a potent antifungal agent.     

The polysaccharides of mango seeds (mangifera indica,var. bullock's heart)

Mangoes (Mangifera indica) are grown in many warm regions of the world; for example, in Australia, Brazil, India, South America, and the United States (California and Florida), and along the shores of the Mediterranean sea (Egypt, Italy, and Spain). In Egypt, many varieties yielding delicious fruits are grown in large quantities (50,000 tons annually). Mango kernels are used for feeding mammals and chickens. Starch has been isolated from mango and its physical properties studied.The aim of the present work was to study the polysaccharides present in mango kernels.     

The effect of sodium chlorate and nitrapyrin on the nitrification mediated nitrosation process in soils

Summary The influence of total nitrification to nitrate or partial nitrification to nitrite on the soil organic nitrogen status was examined. NH ₄ ⁺ –¹⁵N was added to the soil in the absence and the presence of NaClO₃, respectively nitrapyrin. The first chemical inhibits only nitrate formation, the second inhibits total nitrification. The accumulation of nitrite nitrogen in the soil at levels up to 5 mg kg^–1 increased the loss of nitrogen. Yet, it did not increase the binding of mineral nitrogen into soil organic matter, relative to the control soil. The data suggest that the biochemistry of the nitrite formation process, rather than the levels of nitrite ions formed, are of primary importance in the role of nitrification mediated nitrosation of soil organic matter.     

Decarboxylation of branched-chain alpha-ketoacids in hepatocytes from alloxan-diabetic rats. The effect of insulin

The flux through branched-chain alpha-ketoacid dehydrogenase and the activity of the branched-chain alpha-ketoacid dehydrogenase complex were measured in hepatocytes isolated from fed, starved and alloxan diabetic rats. The highest rate of branched-chain alpha-ketoacid oxidation was found in hepatocytes isolated from starved rats, slightly lower in those from fed rats, and significantly lower in diabetic hepatocytes. The amount of the active form of branched-chain alpha-ketoacid dehydrogenase was only slightly diminished in diabetic hepatocytes, whereas the flux through the dehydrogenase was inversely correlated with the rate of endogenous ketogenesis. The same was observed in hepatocytes isolated from starved rats when branched-chain alpha-ketoacid oxidation was measured in the presence of added oleate. In both cases the diminished flux through the dehydrogenase, restored by a short preincubation of hepatocytes with insulin, was paralleled by a decrease of fatty acid-derived ketogenesis. The significance of these findings is discussed in relation to the role of insulin in branched-chain alpha-ketoacid oxidation in liver of diabetic rats.     

Renal excretion capacity in hydrated desert rodents (Jaculus orientalis andJaculus deserti)

Summary The capacity to excrete a water load was studied in rats and in two desert rodents (Jaculus orientalis andJaculus deserti) adapted to either 5 or 30°C ambient temperature. The rat is able to eliminate the entire water load regardless of thermal adaptation. Cold-adaptedJ. orientalis andJ. deserti excreted 60% of the water load in comparison to 20–30% in warm-adapted jerboas.At both adaptation temperatures, antidiuretic hormone (ADH) concentration was estimated at maximum diuresis in the two desert species. Though hydration induced a significant decrease in ADH concentration in both species, its level in the plasma remained relatively high. The decrease was more pronounced inJ. orientalis thanJ. deserti.Abbreviation ADH antidiuretic hormone     

Motile aeromonas infection of striped (grey) mullet Mugil cephalus

Infection of striped mullet (Mugil cephalus) with Aeromonas hydrophila results in an acute septicemic disease. The disease can be experimentally induced by intramuscular injection, skin or gill scarification or by the oral route using pellets purposely seeded with bacteria. The organism was isolated from the blood 1–2 days after infection and from all organs 24 hr or longer after infection. The disease is characterized by early inflammatory and proliferative changes and later necrotic changes. Enteritis and hepatic necrosis are constant findings in aeromonad disease of M. cephalus but surface lesions are not pathognomic for these infections in mullet. Death of infected fish may be attributed to bacterial toxins which cause necrosis of parenchymal organs and soft tissue structure.     

A bacteriological survey of an oyster-growing area: The Oualidia Lagoon,Morocco

A 3-year bacteriological survey of an oyster-growing area in Morocco, where the Japanese oyster (Crassostrea gigas) is grown, showed that the contamination of this lagunar ecosystem was not continuous but intermittent and that animal manure and human recreational activities were important sources of pollution. The major source of contamination was of animal origin, except during the summer, when human contamination prevailed.     

Specific inhibition of human granulocyte elastase with peptide aldehydes

The kinetic features of human granulocyte elastase, chymotrypsin, porcine pancreatic elastase and elastomucoproteinase were compared. Amino acyl ester substrates were assayed and Km and kcat values were defined. Aldehyde analogues of the p-nitroanilide substrates designed for granulocyte elastase as optimal for Km appeared to be potent inhibitors. Suc-D-Phe-Pro-valinal (Ki = 40 microM) was found to inhibit granulocyte elastase competitively and specifically when measured with synthetic substrates, and the Ki was 3 microM with the natural protein substrate, elastin.     

Nitrification and organic nitrogen formation in soils

Summary The formation of mineral nitrogen species and of organic nitrogen was studied in three different types of soils in relation to the application of the nitrification inhibitor nitrapyrin. The results indicate that nitrification brings about a deficit in total mineral nitrogen and a concomitant surplus in non biomass organic nitrogen. This phenomenon increases with increasing levels of applied ammonium nitrogen and soil organic matter. The phenomenon is considered to be due to the reaction of the transient nitrite formed with soil phenolic compounds and appears to be of significance in all soils in which nitrification occurs, even neutral to alkaline and low carbon soils.