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.     

Horseradish peroxidase: a reliable or a misleading tool for the investigations on the origin of the proteins of the aqueous humor?

The concept of the blood-aqueous barrier is largely based on the use of horseradish peroxidase (HRP). The present investigation was designed to check its reliability as a macromolecular tracer, especially with regard to the transport of plasma proteins. Rabbits were killed 5 min to 24 h after being intravenously injected with HRP. The tracer diffused rapidly, reaching the aqueous humor of the eye in 3 min or less and was detected at high concentration in the narrow space between the outer epithelial layer of the ciliary epithelium and the wall of the pervious capillaries in the stroma of the processes. HRP appeared to migrate from the blood to the posterior chamber, permeating the tight junctions, viz., the anatomical basis of the blood-aqueous barrier. It was detected at higher concentration at the anterior surface of the iris, at short time intervals; this was interpreted as penetration of the tracer from the aqueous humor of the anterior chamber. The choroid was also labeled in continuation with the reaction in the stroma of the pars plana of the ciliary body which, in turn, sometimes reached the iris root. Therefore, the pervious blood vessels of the choroid could be a source of macromolecules for the iris root. HRP also induced the formation of lysosomes in the ciliary epithelium. This can hardly be accepted as the way in which plasma proteins are physiologically transported to the aqueous humor. However, the pathway of HRP migration over short time intervals seems to be in agreement with previous research indicating that the entrance of serum albumin into the posterior chamber is the first step of its incorporation into the aqueous humor. Received: 7 June 1996 / Accepted: 15 January 1997     

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.     

Plasma Levels and Therapeutic Effect of 25-Hydroxycholecalciferol in Epileptic Patients taking Anticonvulsant Drugs

Plasma levels of 25-hydroxycholecalciferol (25-HCC) were measured by a specific competitive protein-binding assay. Mean levels in both normal London adults and adolescent schoolchildren were 16 ng/ml and the mean level in a group of epileptic patients on high-dosage anticonvulsant therapy was 5 ng/ml, (difference from normals P < 0·001). Two further epileptic patients, with well-marked anticonvulsant osteomalacia, were treated with small doses of 25-HCC during full metabolic balance studies; rapid healing followed administration of 25-HCC by mouth in doses of 10-45 μg daily, which is well below the effective dose range of calciferol in this condition. These findings provided further evidence that anticonvulsant osteomalacia results from hepatic enzyme induction which, by increasing the metabolism of cholecalciferol to inactive compounds, lowers 25-HCC levels in patients whose dietary vitamin D intake and exposure to sunlight are otherwise adequate. Results also indicated that under certain circumstances 25-HCC may have considerably stronger antirachitic potency in man than has hitherto been recognized.     

Influence of acetic and butyric acid addition on polysaccharide formation byClostridium acetobutylicum

Summary The production of granulose (an intracellular reserve polygranule), capsule and exopolysaccharide was investigated in a synthetic medium in which the oxido-reduction level was modified by the addition of acetic or butyric acid. After addition of the acids, granulose synthesis increased from 150 to 300 mg glucose equivalents ·1^–1 and capsular synthesis decreased by 25%. Exopolysaccharide production was unchanged under these conditions. A hypothesis that attributes a role to the polymer in the oxido-reduction sequences is discussed.