Synthesis and beta-lactamase inhibitory activity of new 6beta-cysteinesulfonamidopenicillanic acids

New 6beta-cysteinesulfonamidopenicillanic acids and their sulfoxides were synthesized by sulfonylation of 6beta-aminopenicillanic acid or its (S)-sulfoxide with (R)-N-benzyloxycarbonylcysteinesulfonyl chloride ethyl ester (2a, 1b) and (R)-N-benzyloxycarbonylcysteinesulfonyl chloride benzyl ester (2a, 2b). The corresponding 6beta-cysteinesulfonamidopenicillanic acids sulfones 1c and 2c were prepared by oxidation of the sulfoxides 1b and 2b with potassium permanganate in aqueous medium. When combined with ampicillin some of the compounds reduced the minimal inhibitory concentrations of ampicillin against beta-lactamase producing strains.     

A comparative study of the level of knowledge of schoolchildren about HIV infection and AIDS

The comparative study of the level knowledge on HIV infection and AIDS among school children was carried out. The prophylactic work among school children yielded positive results, which was statistically confirmed by the analysis of answers to questionnaires, distributed before and after lectures.     

Interaction of natural polyhydroxy-1,4-naphthoquinones with superoxide anion-radical

The interaction of natural polyhydroxy-1,4-naphthoquinones (PHNQ) with superoxide anion-radical (O2) was studied by UV--visible spectrophotometry. 3-Acetyl-2,6,7-trihydroxynaphthazarin (spinochrome C), 2,3,7-trihydroxynaphthazarin (spinochrome D), 2,3,6, 7-tetrahydroxynaphthazarin (spinochrome E), 6-ethyl-2,3, 7-trihydroxynaphthazarin (echinochrome A), 6-ethyl-2,3, 7-trimethoxynaphthazarin (trimethoxyechinochrome A), and 2, 3-dihydroxy-6,7-dimethylnaphthazarin (A618) were tested. Xanthine and xanthine oxidase were used to generate **O2. The interaction with O2 led to significant time-dependent changes in the spectra of echinochrome A and spinochromes D and E. There was a weak influence of O2 on the spinochrome C spectrum and no change in the trimethoxyechinochrome A spectrum. The spectra that were transforming during the time of the reaction contained a pronounced isobestic point. This indicates that a single reaction product is being formed. We suggest that 1,2,3,4-tetraketones are formed from 2, 3,5,8-tetrahydroxy-1,4-naphthoquinones (echinochrome A and spinochromes D and E) via O2-induced oxidation of their OH-groups in the 2nd and 3rd positions. Reaction constants were determined by a competitive method using nitro blue tetrazolium (NBT). The reaction constants were about 104-105 M-1.sec-1. They decreased in the sequence: echinochrome A > spinochrome D > spinochrome C > NBT > trimethoxyechinochrome A. Thus, we conclude that some of the natural PHNQ containing hydroxyl groups in the 2nd and 3rd positions may act as powerful superoxide anion-radical scavengers.     

The postnatal ontogenetic characteristics of adrenal function in female water voles Arvicola terrestris with different fur colors

Studies have been made of the effect of colour mutation on the development of the adrenals in female aquatic voles. Colour mutation in homozygote results in retarded growth rate of the whole body and the adrenals, as well as in postnatal changes in the dynamics of corticosteron content in the blood. Obviously, the effect of colour mutation on plasma concentrations of corticosteron is realised mainly via extra-adrenal mechanisms since no differences were found in corticosteron production by the adrenals and in the adrenal reaction to ACTH (5 U/g of the adrenals) in vitro in growing aquatic voles. During postnatal life, mutant black females exhibited lower sensitivity of the adrenals to the inhibitory influence of estradiol (40 ng/100 mg of the adrenals) as compared to wild phenotype animals.     

Analyzing heat capacity profiles of peptide-containing membranes: cluster formation of gramicidin A

The analysis of peptide and protein partitioning in lipid membranes is of high relevance for the understanding of biomembrane function. We used statistical thermodynamics analysis to demonstrate the effect of peptide mixing behavior on heat capacity profiles of lipid membranes with the aim to predict peptide aggregation from c(P)-profiles. This analysis was applied to interpret calorimetric data on the interaction of the antibiotic peptide gramicidin A with lipid membranes. The shape of the heat capacity profiles was found to be consistent with peptide clustering in both gel and fluid phase. Applying atomic force microscopy, we found gramicidin A aggregates and established a close link between thermodynamics data and microscopic imaging. On the basis of these findings we described the effect of proteins on local fluctuations. It is shown that the elastic properties of the membrane are influenced in the peptide environment.     

Structure of an acidic polysaccharide from the marine bacterium Pseudoalteromonas flavipulchra NCIMB 2033(T)

An acidic polysaccharide was isolated from Pseudoalteromonas flavipulchra type strain NCIMB 2033(T) and found to consist of 6-deoxy-L-talose (L-6dTal), D-galactose and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo). The identities of the monosaccharides were ascertained by sugar analysis and 1D 1H and 13C NMR spectroscopy in conjunction with 2D COSY, TOCSY, ROESY and 1H, 13C HMQC experiments, which enabled determination of the following structure of the trisaccharide repeating unit of the polysaccharide:-->3)-alpha-L-6dTalp4Ac-(1-->3)-beta-D-Galp-(1-->7)-alpha-Kdop-(2-->.     

Ecophysiological variabilities in ectohydrolytic enzyme activities of some Pseudoalteromonas species,P. citrea,P. issachenkonii,and P. nigrifaciens

The ecophysiological variabilities in the ectohydrolytic enzyme profiles of the three species of Pseudoalteromonas, P. citrea, P. issachenkonii, and P. nigrifaciens, have been investigated. Forty-one bacteria isolated from several invertebrates, macroalgae, sea grass, and the surrounding water exhibited different patterns of hydrolytic enzyme activities measured as the hydrolysis of either native biopolymers or fluorogenic substrates. The activities of the following enzymes were assayed: proteinase, tyrosinase, lipase, amylase, chitinase, agarase, fucoidan hydrolase, laminaranase, alginase, pustulanase, cellulase, beta-glucosidase, alpha- and beta-galactosidases, beta-N-acetylglucosaminidase, beta-glucosaminidase, beta-xylosidase, and alpha-mannosidase. The occurrence and cell-specific activities of all enzymes varied over a broad range (from 0 to 44 micromol EU per hour) and depended not only on taxonomic affiliation of the strain, but also on the source/place of its isolation. This suggests 'specialization' of different species for different types of polymeric substrates as, for example, all strains of P. citrea and P. issachenkonii hydrolyzed alginate and laminaran, while strains of P. nigrifaciens were lacking the ability to hydrolyze most of the algal polysaccharides. The incidence of certain enzymes such as fucoidan hydrolases, alginate lyases, agarases, and alpha-galactosidases might be strain specific and reflect its particular ecological habitat.     

Copper-homocysteine complexes and potential physiological actions

During the last 2 decades it was proposed that atherogenesis was closely related to the homeostasis of homocysteine (hCys) and/or copper. We hypothesized that the physiological action of hCys may be connected with its ability to form complexes with Cu. Our results showed the presence of two different Cu-hCys complexes. At a molar ratio Cu:hCys 1:1, a blue complex most probably consistent with a tentative dimeric Cu(II)(2)(hCys)(2)(H(2)O)(2) formula was formed, with tetrahedral Cu coordination and anti-ferromagnetic properties. The redox processes between Cu(II) and hCys, in a molar ratio > or =1:3 led to formation of a second yellow Cu(I)hCys complex. Both Cu-hCys complexes affected the metabolism of extracellular thiols more than hCys alone and inhibited glutathione peroxidase-1 activity and mRNA abundance. The biological action of hCys and Cu-hCys complexes involved remodeling and phosphorylation of focal adhesion complexes and paxillin. The adhesive interactions of monocytes with an endothelial monolayer led to the redistribution of both paxillin and F-actin after all treatments, but the diapedesis of monocytes through endothelial cell monolayer was both greater and faster in the presence of the tentative Cu(II)(2)(hCys)(2)(H(2)O)(2) complex. Together, these observations suggest that Cu-hCys complexes actively participate in the biochemical responses of endothelial cells that are involved in the aethiopathogenesis of atherosclerosis.     

Formation of chromoneme-like fibrils induced in infusorian somatic nuclei by magnesium ions

A study was made of the effect of Mg2+ on higher-order chromatin structure in marconuclei (Ma) of infusoria Paramecium aurelia and Bursaria truncatella. In infusorian Ma, inactive chromatin is commonly packed in chromatin bodies sized 60-200 nm. When isolated chromatin or Ma were treated with Mg2+ (about 3 mM), chromatin bodies arranged into fibrils 100-300 nm in diameter, which resembled higher eukaryotic chromonemes. The formation dynamics of chromoneme-like fibrils was described. The results testified to the similarity of chromatin bodies to chromomeres of higher eukaryotes. Structurally intact central chromomere cores proved to be essential for the formation of chromoneme-like fibrils. Chromatin organization in infusoria was shown to follow the discrete-level model (nucleosomes-nucleomeres-chromomeres-chromonemes) assumed for higher eukaryotes.