[Effect of polyoxyalkanoate -based cover on properties of suture material].

The results of a surgical intervention and, in particular, reconstructive operations on arteries are largely influenced by suture material. Despite a wide range of choice, the market concerned lacks suture material which would make it possible to decrease the risk of thrombosis in the area of the vascular anastomosis. In order to increase bio- and haemocompatibility, the surface of a polypropylene thread was covered with a layer based on polyoxyalkanoates - polyhydroxybutyrate and copolymer polyhydroxybutyrate-oxyvaleriate (PHBV). The strongest and most uniformly distributed coating of the polypropylene thread was provided by PHBV. We assessed the bio- and haemocompatibility properties of suture material modified by PHBV, revealing that this modification does not exert negative effect on the main components of blood - thrombocytes and erythrocytes. Treatment of the thread's surface with PHBV promoted a significant (p<0.05) decrease in the amount of absorbed proteins in the area of the vascular anastomosis in experiment: the amount of IgM decreased by 26%, that of fibrinogen by 29%, and that of D-Dimer by 281%, being on the whole indicative of bio- and haemocompatibility of the modified suture material.

[Genetic modification of Methylobacterium extorquens G10 producer strain of polyhydroxybutyrate].

The effect of the increased copy number of polyhydroxybutyrate (PHB) biosynthesis genes in pink-pigmented methylobacterium Methylobacterium extorquens G10 on properties of the biopolymer was studied. The activity of poly-3-hydroxybutyril-synthase (PHB-synthase) was shown to increase and the molecular weight of synthesized PHB decreases twofold (150 --> 79 kDa) after insertion of extra copies of phaC and phaCAB genes into cells of the producer strain, whereas the physicochemical properties of the plastic changed insignificantly. White mutant M. extorquens G10-W with disrupted synthesis of the carotenoid pigment (defect by the crtI gene, which codes for phytoene desaturase) was established to have the same rate of growth and level of PHB accumulation as the initial strain G10. The G10-W strain is a promising producer of PHB, with decreased expenses for purification and PHB biosynthesis.

[Comparative characteristics of biosynthesis of polyhydroxybutyrate from methanol by Methylobacteria extorquens G10 and Methyloligella halotolerans C2].

The biosynthesis of polyhydroxybutyrate by Methylobacteria extorquens G10 and Methyloligella halotolerans C2 via the serine pathway of C1 metabolism was comparatively studied. Nitrogen limitation stimulated synthesis of the biopolymer in both cultures. It was shown that, despite the similarity of the pathways of methanol metabolism and those of polyhydroxybutyrate biosynthesis, the methylobacteria synthesized polymers of different molecular weights. In the case of M. extorquens G10, an increase in the content of the residual nitrogen in the culture medium was found to result in a reduction of the molecular weight of the polymer from 250 to 85 kDa, whereas M. halotolerans C2 synthesized a polymer of high molecular weight (approximately 3000 kDa) regardless of the residual content of the nitrogen source. It was established that the examined methylobacteria can utilize not only pure methanol but also a crude one, a feature that made it possible to significantly reduce the cost of the resulting polyhydroxybutyrate.

[Biosynthesis of polyhydroxybutyrate/valerate with different molecular weights during the growth of Methylobacterium extorquens G-10 on a methanol-pentanol mixture].

The influence of the concentration and time of addition of cosubstrate (pentanol) on the molecular weight (MW) of the polyhydroxybutyrate/valerate (PHBV) copolymer synthesized by Methylobacterium extorquens G-10 during cultivation in a methanol-containing medium has been studied. It was shown that an increase in the pentanol concentration to 20% in a mixture with methanol stimulated the biosynthesis of PHBV with a MW of approximately 1500 kDa and increased the content of valerate up to 50%, especially when pentanol was added to the log phase culture. High pentanol concentrations are toxic for the producer and reduce the total yield of PHBV. An MW increase to 1500 kDa lowers the melting temperature (from 172 to 162 degrees C) and the crystallinity degree (from 63 to 8%) of the biopolymer but increases its elasticity. The revealed variability of PHBV properties extends considerably the potential application areas of synthetic bioplastics.

[EDTA degradation by cells of Chelativorans oligotrophicus immobilized on a biofilter].

A biofilter based on light expanded clay aggregate (LECA) and cells of the obligate ethylenediamine tetraacetate (EDTA) destructor Chelativorans oligotrophicus LPM-4 has been developed. The culture steadily maintained a high level of EDTA monooxygenase activity of 180-200 nmol/min/mg of protein during three months. EDTA was converted completely or by 80% at initial concentrations of 0.5-0.7 or 2.0 g/l, respectively, in a 2-dm2 biofilter at a flow rate of 20 ml/h.

[Biosynthesis of the bioprotectant ectoin by aerobic methylotrophic bacteria from methanol].

It is shown that neutrophilic methylobacteria Methylophaga thalassica and M. marina have higher rates of growth and ectoin accumulation compared to the haloalkaliphilic species M. alcalica and M. natronia and methanotrophs Methylomicrobium alcaliphilum and M. kenyense. The conditions of M. thalassica cultivation in methanol-containing medium were optimized. The yield of this process reached 60 g/l of absolutely dry biomass containing 15-19% (9-11 g/l) ectoine. The scheme of ectoin isolation from the biomass by extraction and subsequent purification, which allowed obtaining preparations of different degree of purity, was developed.

[Growth of Methylosinus trichosporium OB3b on methane and poly-beta-hydroxybutyrate biosynthesis].

Optimal conditions for batch cultivation of the obligate methanotroph Methylosinus trichosporium OB3b on methane without superatmospheric pressure were chosen. The yield of absolutely dry biomass after 120 h of growth reached 20 g/l. This biomass contained 30% poly-beta-hydroxybutyrate (PHB) with molecular weight 300 kDa. The growth process included the stages of biomass growth and PHB biosynthesis. The latter stage occurred under nitrogen-deficiency conditions. It was accompanied by an increase in the activity of PHB biosynthesis enzymes (beta-ketothiolase, acetoacetyl-CoA reductase, and PHB synthase) and the main NAD(P)H producer, methylenetetrahydromethanopterin dehydrogenase. The activity of PHB depolymerase increased insignificantly.

[Biodegradation of methyl and ethyl acetates by immobilized Pseudomonas esterophilus cells].

A biofilter based on polyvinylformal foam and Pseudomonas esterophilus strain VKM V-1436D cells, which utilize methyl and ethyl acetates as sources of carbon and energy, was created. A complete conversion of methyl and ethyl acetate (2000 mg/l) under flow conditions was reached. Because carboxyl esterase does not exhibit specificity for these esters, no adaptation period was required for switching the biofilter between biodegradation of methyl acetate and ethyl acetate.

[Biosynthesis of bovine growth hormone in Escherichia coli DH1 cells and its purification on a pilot scale]. / Biosintez bych'ego gormona rosta v kletkakh Escherichia coli DH1 i ego vydelenie na pilotnom urovne.

The biosynthesis of the bovine growth hormone (BGH) in E. coli DH1 cells containing the plasmid pbGH(1-119)ptrp was studied. It was found that BGH accumulated in the cytoplasm of bacterial cells as optically dense granules that can be isolated by low-speed centrifugation. A fraction of purified protein granules was used for further purification of BGH. A purified BGH preparation contained two polypeptides with molecular weights of 18,000 and 22,000 D. The state of plasmid was investigated during cultivation and storage of the culture.

[The effect of growth rate and culturing conditions on the stability of plasmid pCJ55 and on the level of expression of a large fragment of DNA-polymerase I, cloned in Escherichia coli]. / Vliiane skorosti rosta i uslovii kul'tivirovaniia na stabil'nost' plazmidy pCJ55 i na uroven' ékspressii bol'shogo fragmenta DNA- polimerazy I, klonirovannogo v Escherichia coli.

Plasmid pCJ55 with a cloned gene for the large fragment of Escherichia coli DNA polymerase I is stable in the population of a recombinant strain under the conditions of batch and continuous cultivation at different dilution rates in the presence of ampicillin. The level of Klenow fragment expression is determined by at least two factors: the stability of the recombinant strain and its specific growth rate. The maximal activity of the Klenow fragment was found after thermoinduction of the culture growing at a rate of mu = 0.6 h-1 in a synthetic medium with bactopeptone and glucose as a carbon source.

[Results of the use of dalargin electrophoresis to correct mental disorders in patients with hypertension grades I and II]. / Rezul'taty primeneniia dalargin-élektroforeza s tsel'iu korrektsii psikhicheskogo sostoianiia bol'nykh gipertonicheskoi bolezn'iu I i II stadii.

Dalargin, a small regulatory peptide produced in the USSR was tested with respect to its effect on psychological indices in 80 patients with essential hypertension grades I and II. Endonasal Dalargin electrophoresis was applied in 50 patients and 30 were subjected to endonasal galvanization (the control group). Electrophoretically applied Dalargin was shown to accelerate the sensorimotor responses, improve memory, reduce the anxiety levels.

[Isolation and purification of various extracellular ribonucleases from Penicillium brevi-compactum in a single technological cycle]. / Vydelenie i ochistka preparatov razlichnykh vnekletochnyky nibnukleaz Brevi-compactum v edinom tekhnologicheskom tsikle.

The possibility of producing nonspecific acid and guanyl-specific alkaline ribonucleases of Penicillium brevi-compactum in a single technological cycle was explored. The use of pre-purification of anion exchanger EDE-10P and strongly basic anion exchanging fiber CM-A2 at an initial stage produced a solution of enzymes, from which both enzymes in a pure form and with a high yield were isolated, using CM-cellulose and Sephadex G-75 chromatography. Both enzymes proved homogeneous with respect to protein.

[Sorption of acid ribonuclease from Penicillium brevi-compactum by various ion-exchange resins]. / Izuchenie sorbtsii kisloi ribonukleazy Penicillium Brevi-compactum razlichnymi ionitami.

Sorption of acid ribonuclease from Penicillium brevi-compactum F-399 was studied. The effect of nature and structure of various ion-exchange resins on the sorption capacity and reversibility was determined. High rate and reversibility of the enzyme sorption on the strong base anion-exchange fiber TsM-A2 were demonstrated. It is suggested that sorption of acid ribonuclease of the TsM-A2 fiber proceeds as ion exchange and on carboxyl cation exchange resins as molecular sorption.

[Effect of phosphate and glucose on the growth kinetics and phsophohydrolase activity of Penicillium brevi-compactum]. / Vliianie fosfata i gliukozy na kinetiku rosta i fosfogidrolaznuiu aktivnost' Penicillium brevi-compactum.

The kinetics of growth of Penicillium brevi-compactum and the activity of exocellular phosphohydrolases were studied on media with different concentrations of glucose and phosphate. Exocellular phosphohydrolases were synthesized when the growth was decelerated due to the deficiency of phosphate rather than that of glucose. These enzymes were not synthesized if the growth was not limited by phosphate. Synthesis of exocellular phosphohydrolases was repressed by phosphate when the growth was limited by glucose. Apparently, a complex of exocellular phosphohydrolases is synthesized by the culture if its growth is limited by phosphate.

[Continuous cultivation of Penicillium brevicompactum that forms extracellular ribonucleases]. / Nepreryvnoe kul'tivirovanie Penicillium brevicompactum, obrazuiushchego vnekletochnye ribonukleazy.

Conditions for continuous cultivation of Penicillium brevi-compactum producing extra-cellular ribonucleases were studied. The two-step process of fermentation in the course of which the flow of the medium in the first fermenter was maintained at 0.054 hr-1, and in the second fermenter at 0.0527 hr-1, made it possible to produce 3--4 times more enzymes as compared to the batch culture.

[Regulation of the biosynthesis of extracellular phosphohydrolases in Penicillium brevicompactum]. / O reguliatsii biosinteza vnekletochnykh fosfogidrolaz u Penicillium brevicompactum.

The effect of certain metabolites of Penicillium brevi-compactum on the biosynthesis of exocellular ribonucleases and phosphomonoesterase was studied. Their synthesis was found to be inhibited by RNA and AMP, as well as by high concentrations of these enzymes in the medium. The mechanism which regulates the biosynthesis of exocellular phosphohydrolases by both phosphate and the enzymes is discussed.

[Effect of cultivation temperature and pH on the biosynthesis of extracellular phosphohydrolases by the culture Penicillium brevi-compactum]. / Vliianie temperatury i pH kul'tivirovaniia na biosintez vnekletochnykh fosfogidrolaz kul'turoi Penicillium brevi-compactum.

The effect of cultivation temperature and pH on growth of the culture Penicillium brevi-compactum and biosynthesis of extracellular phosphohydrolases (acid and alkaline RNases and acid PMEase) involved in RNA degradation was studied. The maximum growth of the culture was seen at 30 degrees and pA-7.0 and its maximum physiological activity with respect to the above enzymes was noted at 24 degrees and pH = 3.0, i.e. optimal conditions for the biosynthesis of phosphohydrolases did not coincide with those for the culture growth. The cultivation temperature and pH produced an effect on the oxygen consumption and synthesis of extracellular phosphohydrolases by the culture.

[Effect of culture medium components on the biosynthesis of acid ribonuclease by Penicillium brevicompactum cultures]. / Vliianie komponentov pitatel'noi sredy na biosintez kisloi ribonukleazy kul'turoi pencillium brevi - compactum.

The effect of different ingredients of the nutrient medium on the synthesis of acid ribonuclease by the culture Penicillium brevi-compactum was studied. The synthesis of RNase reached maximum on the medium containing glucose, pepton, soya bean flour, ammonium sulphate. An excessive content of phosphate in the medium decreased the RNase synthesis. An optimal medium for the synthesis of the enzymes was developed and recommended.