Liquid chromatography method for simultaneous analysis of amino acids and biogenic amines in biological fluids with simultaneous gradient of pH and acetonitrile

A liquid chromatography method for simultaneous analysis of amino acids, polyamines, catecholeamines and metanephrines in human body fluids after derivatization with 9-fluorenylmethyloxycarbonyl chloride was developed. The chromatographic behavior of analytes at different pH of mobile phase was studied. Successful baseline resolution of all analyzed compounds was achieved using simultaneous gradient of pH and organic modifier in reverse phase mode of HPLC within 36 min. The repeatability of the proposed procedure in respect of retention time and peak area, expressed as RSD, ranges from 0.06 to 1.64% and 0.4 to 7.6%, respectively. The method linearity in the range of 1-200 microM for amino acids and in the range of 0.1-20 microM for polyamines, catecholeamines and metanephrines was found to be with correlation coefficients higher than 0.994. The limit of quantification (LOQ) was assessed to be in the range of 2.6-10 pmol for amino acids and 2-4 pmol for polyamines, catecholeamines and metanephrines.     

The organization of medical aid to children of various cohorts of supervision, undergone to the influence of small dozes of radiation

In clause the stages of organization of medical aid to children who undergone to the influence of the ecopathologic factors, including small dozes of ionizing radiation are submitted. The features of various stages of medical aid in nearest time after influence of the radiating agent are shown. The methodological complexities of diagnostic measures in the late times after the ecopathologic influence of small dozes of ionizing radiation are submitted, the role of the radiosensitivity in formation of pathological somatic diseases of condition at children is considered. The opportunity of the differential treating and preventive help rendering to the children various cohorts of supervision is shown.     

Formation of the nanostructure on a silica surface as mercury(II) ions adsorption sites

The present work investigates the adsorptive interactions of Hg(II) ions with hydroxylated silica, aminopropylsilica and silica chemically modified by β-cyclodextrin in aqueous medium. Batch adsorption studies were carried out with various agitation time and mercury(II) concentration. The maximum adsorption was observed within 15-30 min of agitation. The kinetics of the interactions, tested with model of Lagergren for pseudo-first and pseudo-second order equations, showed better agreement with first order kinetics (k₁ = 3.4 ± 0.2 to 5.9 ± 0.3 min⁻¹). The adsorption data gave good fits with Langmuir isotherms. The results have shown that β-cyclodextrin-containing adsorbent has the largest adsorption specificity to Hg(II) : K_L = 14 400 ± 700 L/mg. “β-Cyclodextrin-” inclusion complexes with ratio 1:1 and super molecules with composition С₄₂H₇₀O₃₅ · 3Hg(NO₃)₂ are formed on the surface of β-cyclodextrin-containing silica.     

Antibacterial activity of Cry- and Cyt-proteins from Bacillus thuringiensis ssp. israelensis

Mosquitocidal endotoxins Cry4B, Cry11A, and CytA from Bacillus thuringiensis ssp. israelensis as well as the products of their limited proteolysis display antibacterial activity relative to Micrococcus luteus. The endotoxin Cry11A also induces the lysis of the micrococcus protoplasts. Potassium and sodium ions and N-acetylgalactosamine increased the antibacterial effect of Cry11A, whereas glucose and N-acetylglucosamine inhibited it. The endotoxin Cry11A displays the antibacterial effect on some other microorganisms.     

Field and laboratory studies of Ophryoglena sp. (Ciliata: Ophryoglenidae) infection in zebra mussels,Dreissena polymorpha (Bivalvia: Dreissenidae)

This study, conducted in the Dnieper-Bug Canal in Belarus, is the first to monitor the seasonal (June-November) dynamics of infection with the parasitic ciliate Ophryoglena sp. in a zebra mussel (Dreissena polymorpha) population. Mean population prevalence and intensity of infection varied, respectively, from 11 to 62% and from 0.9 to 24.1 ciliates/mussel. Mean prevalence was highly correlated with mussel length in mussels <20 mm (R(2)=0.97) and was lower in larger mussels. Mean infection intensity in mussels 1-25 mm long was similarly correlated with their size (R=0.98), reached a maximum in the 20-25 mm size-class, and then sharply decreased, thus providing evidence, albeit limited, that high intensity of infection might be lethal. Transinfection of zebra mussels by Ophryoglena sp. was achieved in the laboratory-a first for a protozoan parasite of D. polymorpha; from an initial complete lack of infection, mean prevalence and intensity rose, respectively, to 86.7% and 8.3 ciliates/mussel.     

The influence of physical-chemical characteristics of surface modified copper nanoparticles on E. coli cell population growth suppression and on electrostatic properties of their membranes

The biological activity of copper nanoparticles, able to suppress growth of E. coli cells population under contact interactions, was explored. Three types of samples with oxide layers of various sizes, thickness and composition were used in experiments. It was found out, that an increase in electron density on the external membrane of E. coli correlated with copper nanoparticles suppression capability and with lower activation energy of electron transfer on bacteria. The analysis of experimental data helps to correct conditions for obtaining nanoparticles with certain properties of their surface oxide layers. The character of temperature dependence of electron density reveals the electron type of conductivity in contact area of E. coli and nano-particles. These results help to find approach to understanding the nature of toxic influence of copper nano-particles on E. coli cells under contact interaction.     

Mycobacterium smegmatis SftH exemplifies a distinctive clade of superfamily II DNA-dependent ATPases with 3' to 5' translocase and helicase activities

Bacterial DNA helicases are nucleic acid-dependent NTPases that play important roles in DNA replication, recombination and repair. We are interested in the DNA helicases of Mycobacteria, a genus of the phylum Actinobacteria, which includes the human pathogen Mycobacterium tuberculosis and its avirulent relative Mycobacterium smegmatis. Here, we identify and characterize M. smegmatis SftH, a superfamily II helicase with a distinctive domain structure, comprising an N-terminal NTPase domain and a C-terminal DUF1998 domain (containing a putative tetracysteine metal-binding motif). We show that SftH is a monomeric DNA-dependent ATPase/dATPase that translocates 3' to 5' on single-stranded DNA and has 3' to 5' helicase activity. SftH homologs are found in bacteria representing 12 different phyla, being especially prevalent in Actinobacteria (including M. tuberculosis). SftH homologs are evident in more than 30 genera of Archaea. Among eukarya, SftH homologs are present in plants and fungi.