A study of the nitrate and nitrite discharge from the mutant cells of <Emphasis Type="Italic">Neurospora crassa</Emphasis> lacking nitrate and nitrite reductase activities

The Neurospora crassa mutants nit-2 (lacking both nitrite and nitrate reductases) and nit-6 (lacking nitrite reductase) grown in the medium with ammonium chloride as a sole source of nitrogen discharged nitrate and nitrite ions into culture medium. For nit-2, the content of nitrate exceeded that of nitrite in both the homogenate of fungal cells and growth medium; moreover, this difference was more pronounced in the culture medium. Unlike nit-2, the content of nitrite in the cultivation medium of the nit-6 mutant irradiated with visible light for 30 min during the lag phase of carotenogenesis photoinduction displayed a trend of increase as compared with the dark control. Further (to 240 min) irradiation of cells, i.e., irradiation during biosynthesis of carotenoid pigments, leveled this difference.     

Antifungal Surfaces

Applied Biochemistry and Microbiology - This review presents recent data about various types of antifungal surfaces (nanostructured, functionalized, and with modified wettability) used in medicine,...     

Study of intracellular localization of the proteolytic enzyme complex and its protein inhibitors in bombyx grain

Intracellular localization of serine, cysteine and aspartate proteases, as well as their protein inhibitors, in bombyx grain in the postdiapause period of embryogenesis has been studied. Proteolytic activity of aspartate and cysteine proteases was found in lysosomal, mitochondrial, and nuclear fractions of grains. Serine protease activity was not observed in subcellular fractions of grains of the fourth day of postdiapause development. It has been shown that activities of protein inhibitors and certain peptide hydrolases in subcellular fractions provide consistent functioning and fine regulation of the proteolytic enzyme complex.     

A Study of the Complex of Proteolytic Enzymes and Their Protein Inhibitors in the Embryogenesis of the Silkworm

We studied changes in the activities of serin, thiol, and aspartyl proteinases and their protein inhibitors during embryogenesis of the silkworm. The dynamics of the activities of the protein inhibitors and specific proteinases were interrelated, thus providing for the coordination and fine regulation of the functioning of the proteolytic complex of enzymes during embryogenesis. Possible functions of peptidohydrolases and their protein inhibitors in the silkworm are discussed.     

Isolation and properties of carboxylesterase from hemolymph of the silkworm Bombyx mori L

An original procedure for isolation and purification of carboxylesterase from the hemolymph of stage V larvae of one of Bombyx mori strains including precipitation with 10% polyethyleneglycol, ion-exchange chromatography on Sephadex G-200 and chromatography on DEAE-Sephadex A-50, has been developed. The specific activity of the enzyme after purification makes up to 1250 units per mg of protein with a 59% yield. Some physicochemical properties of the enzyme (Mr = 69 000, pI congruent to 4.9, temperature optimum = 40 degrees, pH optimum = 7.2 Km for alpha-naphthyl- and beta-naphthylacetate = 0.11 X 10(-3) and 0.52 X 10(-3) M, respectively) have been determined. Using immunodiffusion in agar gel, the antigenic identity of the enzymes isolated from the hemolymph of two silkworm species has been established.     

Oxylipins and oxylipin synthesis pathways in fungi

Oxylipins are a family of oxygenated fatty acids that are very diverse with regard to origin, structure, and functions. These compounds are found in almost all living beings and serve both as autoregulators of the development of organisms and as communication molecules. The autoregulatory role of oxylipins in fungi is to control the development, reproduction, synthesis of secondary metabolites (including mycotoxins), and adaptive responses. The role of oxylipins in the regulation of pathogenesis accounts for an important aspect of research on the biological activity of these compounds. The synthetic pathways and functions of oxylipins of fungi, the differences between fungal oxylipins and oxylipins from bacteria, higher plants, and mammals, and the role of oxylipins in the interaction of fungi with other organisms are considered in the present review.