[The role of microorgansisms in maintaining the chitin balance in the Barents Sea].

In this study, we investigated chitin hydrolysis by the bacteria inhabiting the ground of the Barents Sea. Four microbial cultures isolated from the ground were described as the genera of Rhodococcus sp., Bacillus sp., Pseudomonas sp., and Acinetobacter sp. Protein complexes with endochitinase and exochitinase activities were purified from the culture liquid. These microorganisms can participate in chitin degradation in sea water. The average molecular weight of the protein fraction with the chitinolytic activity constituted 92­135 kDa. The ratio of the endo-/exochitinase activities of the enzymatic systems was increased in the order Pseudomonas sp. < Bacillus sp. < Acinetobacter sp. < Rhodococcus sp.

[Endomembrane system of fungi: traditional and modern conceptions].

The review is devoted to the endomembrane system in Fungi, which is mostly presented in cell by membrane organelles, taking part in exo- and endocytosis. Main tenets of the modern model of exo- and endocytosis are covered by the example of the apical cells of filamentous fungi. Particular attention is given to studies of endomembrane system, which were carried out by electron microscopy in the last century--the era in science preceding the prevalence of methods of fluorescence microscopy, immune and molecular genetic tagging. Endomembrane organelles, which are described in classical studies, but have not been identified or differentiated from other organelles modern specialists are under consideration. Among these organelles are lomasomes, plasmalemmasomes, membranosomes and myelin-like bodies. Possible reasons for the "loss" of given structures in today's science and its place in modern proposed model of endomembrane system are discussed. In addition, some specific questions are mentioned, namely: the presence of mushroom mycelium endobionts, morphologically similar to endomembrane organelles, and the increase of number of endomembrane structures in bracket fungi, limited in nitrogen nutrition.

New measurement of the K+-->pi+ nunu branching ratio.

Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 < Ppi < 199 MeV/c, with an estimated background of 0.93+/-0.17(stat.) -0.24+0.32(syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K+-->pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.

[Glycolytic activity of enzyme preparation from the red king crab (Paralithodes camtschaticus) hepatopancreas].

Enzyme preparation exhibiting glycolytic activity yielding chitooligosaccharides along with N-acetyl-D-glucosamine was obtained from the red king crab (Paralithodes camtschaticus) hepatopancreas. The results of the analysis confirmed the presence of endo- and exochitinase activities in the preparation. HPLC showed that the hydrolysis products of chitin and chitosan did not contain D(+)-glucosamine, which is indicative of the absence of deacetylase and, apparently, exochitosanase activities. A comparison of the dependence of the enzyme preparation activity on temperature and pH of the incubation medium suggests that chitinase and protease activities are exhibited by different enzymes.

[A new source of methane in boreal forests].

Methane was found among the gases evolved during natural wood decay caused by bracket fungi in boreal forests. Methane was detected both in decaying wood and fungal fruiting bodies. A scheme of symbiotic association of wood-degrading fungi and anaerobic microorganisms providing the methanogenesis in the wood was proposed. The scale of mycogenic methane emission has to be consistent with the huge volume of decaying wood in boreal forest ecosystems.

[Characteristics of proteinase digestive function in invertebrates--inhabitants of cold seas].

Digestive proteinases of various taxa of invertebrates of the Northern seas have been studied: crustaceans Paralithodes camtchaticus, Pandalus borealis; molluscs Chlamys islandicus, Buccinum undatum, Serripes groenlandicus, and echinoderms Strongylocentrotus droebachiensis, Cucumaria frondosa, Asterias rubens, and Grossaster papposus. The presence of two proteolytic activity peaks in the acid (pH 2.5-3.5) and low alkaline zones (pH 7.5-8.5) and a similar proteinase spectrum have been revealed in digestive organs of the studied animals. The proteolytic activity in digestive organs of the Barents Sea invertebrates exceeds significantly that of terrestrial homoiothermal animals, which seems to be an extensive compensation for poor differentiation of the digestive system and for low substrate specificity of the enzymes as well as for cold conditions of the habitat. The principal qualitative difference between vertebrates and invertebrates consists in that the latter have no pepsin activity, but do have the cathepsin activity that is absent in vertebrate digestive organs. Contribution to the acid proteolysis is made by lysosomal cathepsins, rather than by pepsins. Activity in the alkaline and neutral pH zones is provided by serine proteinases. In digestive cavities of invertebrates, hydrolysis of proteins and mechanical processing of food occur only in the low alkaline zone, whereas acid proteolysis has intracellular lysosomal localization.

[Properties of chitinolytic enzymes from the hepatopancreas of the red king crab (Paralithodes camtschaticus)].

Our study confirms the presence of chitinolytic, chitosanolytic, and deacetylase activities in the hepatopancreas of the red king crab, related to the specific diet of this species. The maximum rate of chitin/chitosan hydrolysis by an enzyme preparation from crab hepatopancreas occurs at 36.5-37.0 degrees C. Two pH optimums have been found for the enzymatic reaction under mildly alkaline and acidic conditions for both exo- and endochitinase activities. The enzyme preparation is most affine to partly deacetylated chitin with an acetylation degree within 40-50%.

Improved measurement of the K+-->pi+nunu; branching ratio.

An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211

[Chitosan depolymerization by enzymes from hepatopancreas of the crab Paralithodes camtschaticus]. / Depolimerizatsiia khitozana pod deistviem fermentov gepatopankreasa kamchatskogo kraba Paralithodes camtschaticus.

An enzyme preparation was isolated from the Paralithodes camtschaticus hepatopancreas that exhibited chitinase and chitosanase activities. Treatment of chitin and chitosan with this preparation decreased their viscosity-average molecular weights by 96 and 41%, respectively. The chromatographic profiles of the products of chitin and chitosan hydrolysis suggested that the crab hepatopancreas in rich in endochitinases. Enzymatic digestion of chitosan increased its solubility and moderately reduced the extent of its acetylation. A mathematical approach was proposed for calculating the molecular weights of chitosan fractions from weight-average molecular weights determined viscometrically.

[Mathematical modeling of passive mechanisms of the human vascular regulation in orthostatic position]. / Matematicheskoe modelirovanie passivnykh mekhanizmov reguliatsii sostoianiia sosudistoi sistemy organizma cheloveka v ortostatike.

Formalized description of the vascular component of the human circulation system taking in the effects of gravity on the human organism during the standing test is presented. The structure proposed in the model by R.D. Grigorian has been used as basic to describe the vascular system. The neuroreflex and humoral regulators of circulation have been counted as constant. Organs and elements of the vascular system were represented as a network of sequential and parallel separate elastic reservoirs with distributed parameters. The pressure-volume ratio was represented by piecewise linear approximation with 3 fragments imitating main forms of the vascular cross section. Primary focus was put on investigation of circulation in the leg and the head which is of interest for evaluating body reactions to postural changes. Result of modeling have been displayed as curves of volumetric velocity, and blood volume and pressure in different fragments of cranial and crus vessels.

[Enzymatic hydrolysis of proteins from crustaceans of the Barents Sea]. / Fermentativnyi gidroliz belkov rakoobraznykh Barentseva Moria.

Enzymatic preparations from king crab hepatopancreas were shown to be capable, in principle, of producing protein hydrolysates. Hydrolysis of protein-containing waste of deep-water prawn and king crab occurs most successfully at pH 8.0-8.5 and 50-55 degrees C for 5-6 h in the presence of 6 g enzyme per kg substrate. The total chemical composition of the hydrolysates, the molecular weight distributions of proteins and polypeptides, and the contents of free amino acids were studied in dry hydrolysates.

[Enzymatic proteinaceous hydrolyzate from the processing waste of the Iceland scallop Chlamys islandica]. / Fermentnyi belkovyi gidrolizat iz otkhodov promysla islandskogo grebeshka Chlamys islandica.

Dry enzymatic hydrolyzate was derived from the protein containing wastes of the Iceland scallop fishery using the complex of proteinases from the king red crab hepatopancreas. The finished product contains not less than 80% of free amino acids and the lowest peptides. Leucine, isoleucine, arginine, lysine and aspartic acids account for to 50% of free amino acids. The applicability appraisal of proteinaceous hydrolyzate from the wastes of the Iceland scallop fishery to use them as the constituents in the nutrient medium for microorganisms was conducted. The approbation of hydrolyzate in the composition of nutrient medium on the test--cultures indicated the high sensibility and germinating capacity of microorganisms.

[The use of chitosan solutions for defatting and clarification of protein hydrolysates]. / Ispol'zovanie rastvorov khitozana dli obezzhirivaniia i osvetleniia belkovykh gidrolizatov.

The possibility of the use of small amounts of chitosan for defatting and clarification of protein solutions prepared by enzymatic hydrolysis was tested. The following treatment conditions were shown to be optimal: chitosan concentration range, from 1.0 to 1.5 g per kg raw weight; pH of precipitation medium, from 8.0 to 8.5; and duration of incubation of protein hydrolysate solution with chitosan, less than 1 h. The hydrolysate defatting grade was found to depend on the degree of chitosan deacetylation. A possible mechanism of the chitosan-induced effects was suggested. The use of chitosan allows the mass fraction of enzyme protein hydrolysates to be reduced fourfold to fivefold.