Influence of transition metals on Streptomyces coelicolor and S. sioyaensis and generation of chromate-reducing mutants

Bacteria-assisted bioremediation is widely recognized as a low-cost method to minimize the consequences of soil pollution with toxic metals originating from industrial sites. Strains used in bioremediation have to deal with high metal load via biosorption, reduction, bioprecipitation, metal sequestration, and/or chelation. Actinobacteria, and streptomycetes in particular, are considered a perspective group for bioremediation as natural soil inhabitants with extensive secondary metabolism. Nevertheless, there is no reference information on survival of the model streptomycetes in the presence of the most abundant metal pollutants. Also, there are no reports describing the selection approaches towards improvement of bioremediation properties. In this work, the resistance of Streptomyces coelicolor M145 and Streptomyces sioyaensis Lv81 to certain transition metals and their growth under different pH values are described for the first time. Spontaneous chromate-resistant S. sioyaensis Lv81-138 strain was selected in the course of this work. Strain Lv81-138 is the most efficient actinobacterial Cr(VI) reducer reported so far, capable of converting 12 mmol/L of Cr(VI) into Cr(III) in a medium supplemented with 50 mmol/L K₂CrO₄.     

Biological effect of 9 GeV protons and the radioprotective effect of ATP and AMP on epithelial cells of the mouse cornea

The cytogenetic and cytological effects induced in mouse cornea epithelium cells by 9 GeV protons and "standard" radiation have been studied. The RBE coefficients are different at different times of observation. ATP and AMP are shown to produce a protective effect on the frequency of formation of aberrant mitoses. DMF values for protons determined 24 and 72 h following irradiation are 1.8 +/- 0.2 and 1.7 +/- 0.2, respectively.     

Characterization of multiple changes of antibiotic resistance characters in Streptomyces coelicolor A3(2)

Among mutants of Streptomyces coelicolor A3(2) studied which were sensitive to chloramphenicol (Cmls), strains sensitive to a number of antibiotics (ristomycin, tetracycline, polymyxin, lincomycin) amount of 46%. Antibiotic-sensitive mutants are capable to form different classes of resistant revertants with frequency varying from 10(-2) to 10(-6) in independent strains. Ristomycin-sensitive clones (Rims) have been found to occur with high frequency in Cmls strains and Cmlr revertants. Mutations mediating the Rims phenotype are mapped in a locus linked to the gene for resistance to chloramphenicol. The results obtained are discussed, in accordance with the notion about possible role of cml mutation in induction of secondary mutational changes in the genome of S. coelicolor A3(2).     

Topography and the protein synthesis level in the large pyramidal neurons during sleep and wakefulness]

In the large pyramidal neurons of the pariental cortex of cat during the slow-waved phase of sleep in comparison to the state of awake, an uneven decrease of the level of 3H-leucine inclusion was established in different functionally specialized zones of the cell. Using electron microscopy, a decrease in the number of polysomes and membrane-attached ribosomes was shown in the perinuclear zone of large pyramids in slow-waved phase of sleep. The results obtained suggest a decrease in the intensity of protein synthesis in comparison to the state of awake.     

Improved protein A resin for antibody capture in a continuous countercurrent tangential chromatography system

Continuous countercurrent tangential chromatography (CCTC) enables steady-state continuous bioprocessing with low-pressure operation and high productivity. CCTC has been applied to initial capture of monoclonal antibodies (mAb) from clarified cell culture harvest and postcapture polishing of mAb; however, these studies were performed with commercial chromatography resins designed for conventional column chromatography. In this study, a small particle size prototype agarose resin (20–25 µm) with lower cross-linking was co-developed with industrial partner Purolite and tested with CCTC. Due to increased binding capacity and faster kinetics, the resulting CCTC process showed more than a 2X increase in productivity, and a 2X reduction in buffer consumption over commercial protein A resins used in previous CCTC studies, as well as more than a 10X productivity increase versus conventional column operation. Single-pass tangential flow filtration was integrated with the CCTC system, enabling simple control of eluate concentration. A scale-up exercise was conducted to provide a quantitative comparison of CCTC and batch column chromatography. These results clearly demonstrate opportunities for using otherwise unpackable soft small particle size resins with CCTC as the core of a continuous bioprocessing platform.     

Interaction of trap colour attractiveness with morphological variability of the thrips Frankliniella occidentalis (Pergande 1895)

In the latitude of Kiev, 80% of Frankliniella occidentalis (Pergande 1895) population was caught on the colour traps from 11 a.m. to 5 p.m. in summer and from 11 a.m. to 3 p.m. in winter. Meanwhile, 10% of the population did not react to the colour traps at all (“passive” individuals), whereas for 20% of the population it was impossible to determine the clear colour with attractive properties. The thrips attracted with blue and yellow color traps, had more massive and variable body parts to be connected with their flight. Their antennae and segment sizes were significantly smaller than compared to the control variant, which could be explained by eyesight domination over other organs of sensory orientation. The indices of heterogeneity of morphological features can be used as evaluation criteria for the adaptive variability and stability of the thrips population.     

Methylation of nogalose during nogalomycin biosynthesis by Streptomyces nogalater Lv65

Nogalamycin is a polyketide antibiotic produced by Streptomyces nogalater Lv65. Antibiotic is glycosylated with nogalose and nogalamine sugar moieties. Bioinformatic analysis of the snogM, snogL, and snogY genes revealed that the products of these genes were involved in methylation of the nogalose moiety of nogalamycin. Disruption of the snogM, snogL, and snogY genes in the chromosome of S. nogalater Lv65 resulted in S. nogalater strains ΔsnogM, ΔsnogL, and ΔsnogY. Inactivation of the O-methyltransferase genes had no affect on the antibiotic activity and morphological features of the recombinant strains. Genetic manipulations with the snogM, snogL, and snogY genes of the nogalamycin biosynthetic gene cluster are a potentially valuable tool for generation of novel anthracycline antibiotics.     

Immune sensor for determining myoglobin level

For the first time, the photoluminescence of porous silicon was used to create an immune sensor capable of detection of low concentrations of myoglobin important for the diagnostics of heart failure diseases which in both model solutions and human serum, being. It is shown that the sensitivity of the sensor was 10 ng/ml, time of 1 measurement--15-30 min. Duration of the analysis can be even shorter if measurements are performed in the kinetic regime. The comparison of the characteristics of the immune sensor and standard method ELISA is also given in the paper.     

Magnetically-guided anesthetics based on highly dispersed iron powders coated by polyacrylamide

The effect of external magnetic field (direct and alternating) on the targeted delivery and distribution in body tissues of experimental animals of anesthetics (novocain, lidocaine, and trimecaine) immobilized on highly dispersed ferromagnetics with biocompatible coating was studied by the method of emission spectral analysis. The results are compared with the results obtained earlier on highly dispersed iron powders with dextran coating. The parameters for the powders with dextran coating are considerably lower than those for the magnetic carriers with the polyacrylamide coating.