Metal proteases from Bac. subtilis]

Metal and serine proteases were separated on the biospecific sorbent. Two different, homogeneous metal proteases were obtained by rechromatography of the metal protease. Activation energies, heat stability, molecular weights, influence of inhibitors, the dependence of activity on pH and temperature were determined. Properties of two metal proteases were compared with those of literary analogs.     

Regulation of exocytotic protein expression and Ca2+-dependent peptide secretion in astrocytes

Vesicular transmitter release from astrocytes influences neuronal development, function and plasticity. However, secretory pathways and the involved molecular mechanisms in astroglial cells are poorly known. In this study, we show that a variety of SNARE and Munc18 isoforms are expressed by cultured astrocytes, with syntaxin-4, Munc18c, SNAP-23 and VAMP-3 being the most abundant variants. Exocytotic protein expression was differentially regulated by activating and differentiating agents. Specifically, proteins controlling Ca²⁺-dependent secretion in neuroendocrine cells were up-regulated after long-term 8Br-cAMP administration in astrocytes, but not by proinflammatory cytokines. Moreover, 8Br-cAMP treatment greatly increased the cellular content of the peptidic vesicle marker secretogranin-2. Release assays performed on cAMP-treated astrocytes showed that basal and stimulated secretogranin-2 secretion are dependent on [Ca²⁺]_i. As shown release of the chimeric hormone ANP.emd from transfected cells, cAMP-induced differentiation in astrocytes enhances Ca²⁺-regulated peptide secretion. We conclude that astroglial cells display distinctive molecular components for exocytosis. Moreover, the regulation of both exocytotic protein expression and Ca²⁺-dependent peptide secretion in astrocytes by differentiating and activating agents suggest that glial secretory pathways are adjusted in different physiological states.     

Gene flow and natal dispersal in the Siberian flying squirrel based on direct and indirect data

Dispersal is a key determinant of the evolution and ecology of species. For a comprehensive picture of dispersal, a combination of both field observations and indirect genetic measures are required, as both of these have strengths that may mitigate the other’s limitations. Here, we used microsatellite markers and radio-telemetry data to study dispersal and gene flow in Siberian flying squirrels. Genetic data confirmed our empirical results that dispersal is female biased in the flying squirrel. Female bias in dispersal is exceptional among mammals and in flying squirrels is probably explained by competition for food resources and nesting cavities among mothers and daughters. The individual-level genetic pattern was influenced by isolation by distance. Using this information fairly comparable dispersal distances were derived using indirect data as observed directly with radio telemetry. Thus, our results support the recent conclusion that individual-level genetic data can be useful in inferring dispersal distances for species for which direct data are lacking.     

A Rapid PCR-Based DNA Test for Enterotoxic Bacillus cereus

The occurrence of DNA sequences encoding the hemolysin HblA complex and Bacillus cereus enterotoxin BceT, which have recently been confirmed as enterotoxins, was studied in Bacillus spp. To amplify these DNA sequences, PCR primer systems for the B component of hblA and for bceT DNA sequences were developed. The results from the amplification of hblA sequences correlated well with results obtained with the B. cereus enterotoxin (diarrheal type) test kit (RPLA kit), but not with the results of the Bacillus diarrheal enterotoxin visual immunoassay (BDE kit). Except for two thermophilic strains, all strains that were positive in PCR amplification assays with the hblA primers were also positive when tested with the RPLA kit. The hblA DNA sequence was found in 33 strains, and these strains were closely related according to 16S rDNA-RFLP analysis, except B. pasteurii. In PCR amplifications with the bceT primers only the model strain gave a positive signal. It is concluded that screening of the hemolysin HblA complex by the PCR method allows faster detection of enterotoxin production than does testing with the RPLA enterotoxin kit.     

Anti-invasive and anti-metastatic effect of lysine oxidase from Trichoderma sp. in vitro and in vivo]

A new fungal strain, Trichoderma sp., discovered in Moscow, produces the antitumor enzyme, lysine-oxidase, which demonstrates an anti-invasive effect in vitro and anti-metastatic activity in vivo. Maximal inhibition of the in vitro invasion of MM1 clone cells was obtained when the tumor cells were pretreated with 2.5 mU/ml of lysine-oxidase; the pretreatment caused a 1.9-times reduction in cell growth and a 1.6-times reduction in the invasive capacity. We studied its anti-metastatic effect on the spreading Lewis lung carcinoma (3LL) in mice from which the primary tumor had been removed. The administration of the enzyme (50 U/kg, i.v.) significantly decreased not only the extent but the number of lung metastases, as compared with the untreated mice. In addition to that, the lysine-oxidase treatment considerably increases the life-span of mice from which the primary tumor had been removed (200 days after 3LL implantation, lysine-oxidase treatment caused surviving of 50% mice in experimental group).     

Defective ALK5 signaling in the neural crest leads to increased postmigratory neural crest cell apoptosis and severe outflow tract defects

Background  

Congenital cardiovascular diseases are the most common form of birth defects in humans. A substantial portion of these defects has been associated with inappropriate induction, migration, differentiation and patterning of pluripotent cardiac neural crest stem cells. While TGF-β-superfamily signaling has been strongly implicated in neural crest cell development, the detailed molecular signaling mechanisms in vivo are still poorly understood.     

Serine proteases from Bac. subtilis]

Using biospecific adsorbent and subsequent gel-filtration of Sephadex G-75 three fractions of serine proteases (I--III) having different physicochemical properties were isolated from Bac. subtilis. The first protease had molecular weight of 23000--24000 (pH optimum 6,5, activation energy 16,6 ccal/mol. The second one had molecular weight of 29000, pH optimum 11,0, activation energy 14,4 ccal/mol. The third protease was a mixture of proteases with average molecular weights 26000 and pH optima at 7,0, 8,5 and 11,0.     

Effects of environmental factors on the phytoplankton community in the Gulf of Finland – unattended high frequency measurements and multivariate analyses

We studied life history and secondary production of Cheumatopsyche spp. (Trichoptera: Hydropsychidae) in StroublesCreek, a 3rd order stream near Blacksburg, Virginia to compare lifehistories and production dynamics in two reaches with differentland-uses. The upstream reach was influenced by agriculturalactivities and more annual degree-days accumulated in this sectionof the stream. The downstream reach was surrounded by forest,received less thermal input than the upstream reach, and showedlittle evidence of human disturbance. Differences between the twosites included a shift in dominant taxa and changes in voltinismand production of hydropsychids. Cheumatopsyche pettiti(Banks) was dominant at the upstream site, while C. pettitiand Cheumatopsyche oxa Ross were both abundant downstream.Cheumatopsyche larvae and other aquatic insects had higherdensities at the forested downstream site. C. pettiti wasbivoltine at the upstream site, but C. pettiti and C. oxa were partially bivoltine downstream, with a small summergeneration overlapping with continuous emergence of overwinteringlarvae. Cheumatopsyche production at the two sites inStroubles Creek was higher than in forested, low-order streams ofNorth America, but similar to some values obtained at streams inagricultural areas and large rivers. Production was higher at thedownstream site, but the superior bivoltinism at the upstream sitecounterbalanced, to some extent, the increase in larval densitythat caused higher production downstream. The adjustment in lifehistory and production dynamics, in the two reaches, showed theecological plasticity of Cheumatopsyche and the importance ofhydropsychids in the energy flow of moderately disturbedstreams.