[Comparative evaluation of antimicrobial activity of oligochitosans against Klebsiella pneumoniae].

Antibacterial activity of chitosan with different molecular weight at different pH values against gram-negative Klebsiella pneumoniae was studied. It was found that the dependence of inhibition activity of chitosan on its molecular weight was inversed when the medium pH was increased above 7.0. In acidic media higher molecular weight chitosan had the higher antibacterial activity was occured while and in weak alkaline media oligomeric forms of chitosan displayed the inhibition effect only. Our results showed that the antibacterial activity of chitosan against Klebsiella pneumoniae was closely connected with its polycationic nature, and was dependent on the degree of protonation of chitosan amino groups, which at the same time depended on the degree of polymerization and solution pH values.

[The features of the establishment of zones of sanitary protection of the water source].

There are regulatory gaps in sanitary laws, which specify the procedure of approval of projects of sanitary protection zones (SPZ) of water objects. It goes without saying that natural complexes, where water intake is organized, should have a special ecological status, which plays a substantial role in the creation of favorable conditions for human health. Some recommendations are given to improve sanitary legislations. Sanitary regulations and standards (SanPin) 2.1.4.1110-02 as well as the Water Code of the Russian Federation do not fully take into account the statements of some Federal laws regarding the protection of water objects. E.g. according to the Federal law No 33- FL of 14.03.1995 "On specially protected natural reservations" there is a legal base for increasing the status of SPZ of water sources by enlarging the list of Specially Protected Natural Reservations by including SPZ therein.

[Prospects of application of the chitin-binding domains to isolation and purification of recombinant proteins by affinity chromatography: a review].

Properties of substrate-binding domains, some parameters of affinity sorbents, and a number of other special features that were necessary to take into account during creation of chromatographic system for isolation and purification of proteins with incorporated chitin-binding domain were discussed in this review. This method was shown to be successfully used along with metal-chelate affinity chromatography. The metal-chelate affinity chromatography with the use of polyhistidine peptides as affinity labels is successfully applied to isolation, purification, and investigation of recombinant proteins. However, this system had some disadvantages. At present, scientists attracted more and more attention to substrate-binding domains, including those chitin-binding, because they had a number of advantages being used as affinity label.

Mucoadjuvant properties of lipo- and glycoconjugated derivatives of oligochitosans.

Chitosan, (1-4)-2-amino-2-deoxy-beta-d-glucan, is a deacetylated form of chitin, an abundant biodegradable, positively charged natural polysaccharide. Chitosan is used for antigen delivery through mucosal barrier due to its ability to disrupt tight junctions. Here we produced new water-soluble low-molecular weight chitosan (LMW-Chi) lipid derivatives and compared their ability to stimulate humoral response with the effect of unmodified LMW-Chi or its oligosaccharide derivatives. LMW-Chi effectively penetrated into macrophage-like, lymphoid and epithelial cells. It also stimulated in mice IgG production to model proteins delivered either by subcutaneous or intranasal routes. Adjuvant effect of chitosan derivatives was comparable to or lower than that of unmodified LMW-Chi. Thus, it is possible that adjuvant effect is induced by unmodified glucosamine units of chitosan.

[The thermophilic bacteria hydrolyzing agar: characterization of thermostable agarase].

Three strains of anaerobic thermophilic bacteria capable of growing on agarose as a source of energy and carbon were isolated from hot springs near Lake Baikal (Barguzin National Park) and the caldera Uzon (Kamchatka). Cells of all the three strains were spore bacilli with peritrichous flagellation. These isolates grew at a temperature of 55-60 degrees C and pH 6.5-7.0 and fermented a wide range of organic substrates. Analysis of the 16S rRNA sequences allowed us to ascribe the strains B5 and K14 to the genus Thermoanaerobacter and the strain K67 to the genus Caldoanaerobacter. According to the results of DNA-DNA hybridization, B5 was determined as belonging to the species Thermoanaerobacter wiegelii. Agarase was isolated by preparative PAGE and subsequent gel chromatography from the culture liquid of strain B5 grown on the medium containing 0.5% agarose and 0.3% galactose. The molecular weight of this enzyme amounted to 67 kDa and pI, to 4.2. The T. wiegelii B5 agarase was active in the pH range of 3.5 to 7.0 (optimum, 5.2) and temperature range of 50 to 80 degrees C (optimum, 70 degrees C). The preincubation of this enzyme at 90 degrees C for 60 min did not reduce the agarase activity. This activity increased in the presence of metal ions; the maximal effect was observed in the presence of 5 mM Mg2+ and 25 mM Co2+.

[Cloning and expression of variants of the glutaryl-7-aminocephalosporic acid acylase of the bacterium Brevundimonas diminuta in Escherichia coli cells].

The gene coding for glutaryl-7-aminocephalosporic acid acylase (Gl7ACA acylase) of the bacterium Brevundimonas diminuta (BrdGl7ACA), a commercial enzyme widely used in modem biocatalytic technologies for manufacture of b-lactam antibiotics, was cloned. Efficient expression systems for producing a "native" recombinant BrdGl7ACA and its analogs modified by attaching affinity groups--the chitin-binding domain of chitinases A1 and hexahistidine sequence--were designed. It was demonstrated that both the recombinant hybrid proteins and the native Gl7ACA acylase produced in E. coli cells underwent a correct autoproteolytic processing with generation of functionally active enzymes and could be isolated with a high yield using one-step affinity chromatography.

[Effect of the molecular weight of chitosan on its antiviral activity in plants].

The effect of the molecular weight of chitosan on its ability to suppress systemic infection of bean mild mosaic virus in bean (Phasoleus vulgaris L.) plants was studied. The enzymatic hydrolysate of low-molecular-weight chitosan was successively fractionated by ultrafiltration through membranes with decreasing pore size. In total, four chitosan fractions with a weight-average molecular weight varying from 1.2 to 40.4 kDa were obtained. It was shown that the treatments of bean plants with these fractions (chitosan concentration, 10 or 100 microg/ml) inhibited virus accumulation and systemic propagation. The degree of chitosan-induced antiviral resistance increased as the molecular weight of chitosan decreased. The monomers comprising the chitosan molecule-glucosamine and N-acetylglucosamine--exhibited no antiviral activity.

[Regenerating activity and antibacterial effect of low-molecular-weight chitosan].

The antibacterial activity of two low-molecular-weight chitosans (LMWCs) was studied using two wound cultures: E. coli and St. albus. Both LMWCs exhibited antibacterial affect. The would-healing effect of methylcellulose gels comprising LMWCs (72 or 11 kDa) was studied. It was shown that wound-healing properties of gels depend on the molecular weight and concentration of LMWCs. The healing activity of LMWCs was assessed judging by the would half-closure time. The gels exhibiting the greatest healing rate contained 2% 72-kDa LMWC or 0.1% 11-kDa LMWC. The composition of the oligomeric fraction of the 11-kDa LMWC was studied by HPLC. It was shown that the oligomeric moiety of the 11-kDa LMWC represents a mixture of oligomers with a large admixture of monomers (30.82%).

Recombinant destabilase-lysozyme: synthesis de novo in E. coli and action mechanism of the enzyme expressed in Spodoptera frugiperda.

Destabilase-lysozyme (DL) from salivary gland secretion of the medicinal leech (Hirudo medicinalis) is as a member of the invertebrate lysozyme family, which sharply differs from other lysozyme families. In this study, DL lysozyme function was confirmed during expression of a gene encoding DL in Escherichia coli. Several constructs of the expression vectors pKK OmpA and pET-3A with or without bacterial, leech, or yeast signal peptides (SP) were used. The use of a construct without signal peptide genes resulted in normal growth of the transformed cells. Transformation of E. coli cells with the constructs containing SP was accompanied by the disruption of the forming cells. The use of the expression vector pET-32 LTC-System for production of DL as a fusion protein with thioredoxin also resulted in normal cell growth. However, specific activity of DL isolated from such cells was significantly lower than that of enzyme purified from extracts of Spodoptera frugiperda cells, which were infected with the baculovirus vector carrying DL cDNA. It is shown that the action mechanism of invertebrate lysozyme does not differ from that of other families: recombinant DL from S. frugiperda extracts catalyzed cleavage of synthetic substrate, hexamer of N-acetylglucosamine, to di- and tetramers, which is typical for enzymatic function of other lysozyme families.

[Enzymatic hydrolysis of alpha-chitin]. / Fermentativnyi gidroliz alpha-khitin.

It was shown that the enzymatic preparation Celloviridin G20x can be used for the hydrolysis of alpha-chitin of various origin. The purity of the final product of hydrolysis, N-acetylglucosamine, was monitored using HPLC.

[Isolation of highly purified cyclodextrin glucanotransferase from Bacillus sp. 1070]. / Poluchenie vysokoochishennoi tsiklodekstringliukantransferazy iz Bacillus sp. 1070]

Two chromatographic processes for purification of cyclodextringlucanotransferase (CGTase) from Bacillus sp. 1070 was carried out. The enzyme has been purified into 9.5 times on Butyl-Toyopearl and followed immobilized metal ion chromatography on Cu(II)-Iminodiacetic (IDA)-agarose. By the application of second purification scheme (chromatography on Butyl-Toyopearl and DEAE-Sephacel) the specific activity of CGTase has folded into 13.5 times. The purity of enzyme was shown to be approximately 90% by SDS-electrophoreses data. It was shown that isolated enzyme has two isoelectric points estimated as 5.1 and 5.3.

[The systems of prophylactic and ecological support for the Armed Forces: their status and interrelationships]. / Sistemy profilakticheskogo i ékologicheskogo obespecheniia Vooruzhennykh Sil: sostoianie i vzaimosviazi.

In the article the theoretical bases of preventive and ecological maintenance of the armed forces are discussed. It is specified, that the main reason for preventive maintenance is preservation and strengthening of health and performance of the personnel, and for the ecological maintenance-achievement of ecological safety: preservation and restoration of the environment. As a result, protection of the personnel from the effect of the adverse factors is offered as a sub-gain of the ecological maintenance, and a sub-gain of preventive maintenance is the control of the environment protection, which defines the health state of the personnel.

[The use of the universal theory of hygienic standards in military hygiene]. / Primenenie universal'noi teorii gigienicheskogo normirovaniia v voennoi gigiene.

On the basis of an abound practice of hygiene standardization, the authors have elaborated a system of fundamental tenets and premises that correspond to the requirements of a universal theory. It includes norms and standards for a living organisms and the environment. The hygiene standardization foundation is based on the principles of guarantee, social-biological balance, complex and dynamics. The tenets stated in the article confirm interrelation and character of the hygiene standards theory formulation and its prognostic function.

[Improvement in the control of the water supply in military posts]. / O sovershenstvovanii kontrolia za vodosnabzheniem voennykh gorodkov.

The control at water supply on criteria of quantitative and qualitative adequacy--one the major sections of sanitary-and-epidemiologic supervision. To radical improvement of water supply of the population of the country, army and fleet are called to serve entered in action since July 1, 1997 Sanitary rules and norms 2.1.4.559-96 "Drinking water. The hygienic requirement to quality of water of centralized systems of drinking water supply. Quality surveillance". In the interest of increase of epidemiologic safety of drinking water in comparison with GOST 2874-82 specifications of microbiological parameters are severed and a parasitologic parameter is entered. The new document changes accepted early classification of chemical structure of water.