Effect of paracrystalline protein surface layers on predation by Bdellovibrio bacteriovorus.

We determined that paracrystalline protein surface arrays (S layers) protected gram-negative eubacteria from predation by Bdellovibrio bacteriovorus. Aquaspirillum serpens VHA and MW5 and Aquaspirillum sinuosum were resistant to predation by B. bacteriovorus 6-5-S when fully covered by their S layers. The S layer of Aeromonas salmonicida A449 protected the cells from predication by B. bacteriovorus 109J. A predacious, plaque-forming vibrio that lysed an S-layer- variant of Caulobacter crescentus but was not predacious on the parental strain which possessed an S layer was isolated from raw sewage. Since S layers are stable components of many bacterial surfaces in nature, they can provide this protective function in both aquatic and terrestrial habitats where Bdellovibrio spp. are found.     

The effects of magnetic stabilization on the structure and performance of liquid fluidized beds.

Liquid fluidized beds containing porous magnetic ion-exchange particles with densities ca. 1.03-1.16 g mL-1 were examined. The effect of magnetic stabilization was studied, both in terms of bed physical characteristics and sorptive behavior. Maximum applied magnetic field strength was approximately 200 oersted. Breakthrough and pulse analyses were carried out with protein and acetone solutions, respectively, with liquid flow rates ranging from approximately 1 to 3 cm min-1. Acetone pulses in columns containing 7 mL of particles had plate numbers ranging from 2.5 to 18 for magnetically stabilized beds and from 7.8 to 20 for non-stabilized fluidized beds. Under any particular set of conditions, magnetic stabilization always resulted in poorer efficiency, both in pulse analyses and in protein breakthrough experiments.     

Binding of metals to cell envelopes of Escherichia coli K-12.

As representative of gram-negative bacteria, the isolated and purified envelopes of an Escherichia coli K-12 strain were used to determine metal-binding capacity. The envelopes were suspended in 5 mM metal solutions for 10 min and 23 degrees C, separated and washed by centrifugation, and analyzed for metal by either atomic absorption or X-ray fluorescence spectroscopy. Of 32 metals tested, large amounts (> 0.9 mumol/mg [dry weight]) of Hf and Os, intermediate amounts (0.1 to 0.4 mumol/mg [dry weight]) of Pb, Zn, Zr, Fe III, Mn, Mo, Mg, Co, and Ce IV, and small amounts (< 0.1 mumol/mg [dry weight]) of Na, K, Rb, Ca, Sr, Cu, Sc, La, Pr, Sm, U, Fe II, Ru, Ni, Hg, Pt, Pd, Au, and In were detected Li and V were not bound to the envelopes. Electron microscopy of unstained, thin-sectioned material provided an electron-scattering profile for localizing the bound metal within the envelope. Energy-dispersive X-ray analysis of thin sections detected all metals in single envelope vesicles. These data suggest that most metal deposition occurred at the polar head group regions of the constituent membranes or along the peptidoglycan layer. No leaching of envelope components was detected by monitoring radioactive probes within the lipopolysaccharide and peptidoglycan layers during metal uptake experiments, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins from metal-loaded envelopes, or protein and carbohydrate determinations on the wash fluids. These results suggest that membrane integrity was not disturbed under these ionic conditions.     

Interactions of lectins with (Na+ + K+)-ATPase of eel electric organ.

Interaction of lectins with a detergent-solubilized ATPase from eel electric organ was studied. Concanavalin A, which binds to alpha-mannosides, altered the rate of enzyme migration in agar and inhibited the formation of an antigen-antibody precipitate: other lectins had no such effects. Concanavalin A similar amounts partially inhibited (Na+ + K+)-ATPase; this inhibition was reversible by alpha-methylglucoside. There was no corresponding effect of concanavalin A on the potassium p-nitrophenylphosphatase. Concanavalin A also did not interfere with ouabain binding. Thus, concanavalin A binds to an antigenic region also involved in Na+ and/or ATP binding, but does not interact with a K+ site.     

Differences in transpiration of Norway spruce drought stressed trees and trees well supplied with water

The paper focuses on the evaluation of transpiration as a physiological process, which is very sensitive to drought stress. Reactions of 25-year-old Norway spruce (Picea abies (L.) Karst.) trees to drought were examined during 2009 summer. Sap flow rate (SF), meteorological and soil characteristics were measured continually. Vapour pressure deficit of the air (VPD) and cumulative transpiration deficit (KTD) was calculated. During the second half of the vegetation period, the decrease in soil water content was observed and irrigation was applied to a group of spruce trees, while the second group was treated under natural soil drought. On the days, when the differences in transpiration between irrigated (IR) and non-irrigated (NIR) trees were significant (21 days), transpiration of NIR trees was only 23% of the transpiration of IR trees. We found significant differences in transpiration when the soil water content (SWC) of NIR variant at a depth of 5–15 cm ranged from 10.4 to 13.7%. Under both regimes of water availability, daily transpiration significantly responded to atmospheric conditions. However, the influence of all assessed meteorological parameters on SF of NIR trees was significantly lower than on IR tree. The dependency of transpiration on evaporative demands of atmosphere decreased with the decreasing soil moisture. Cumulative transpiration deficit of the stand during the entire evaluated period was 50.9 mm. The difference between the transpiration of the mean NIR tree and of the mean IR tree was 278.8 L over the assessed period of 47 days (5.9 L per day). The transpiration of NIR trees was 40.3% from the transpiration of IR trees during this period.     

Calmodulin kinase II inhibition enhances ischemic preconditioning by augmenting ATP-sensitive K+ current

Mice with genetic inhibition (AC3-I) of the multifunctional Ca(2+)/calmodulin dependent protein kinase II (CaMKII) have improved cardiomyocyte survival after ischemia. Some K(+) currents are up-regulated in AC3-I hearts, but it is unknown if CaMKII inhibition increases the ATP sensitive K(+) current (I(KATP)) that underlies ischemic preconditioning (IP) and confers resistance to ischemia. We hypothesized increased I(KATP) was part of the mechanism for improved ventricular myocyte survival during ischemia in AC3-I mice. AC3-I hearts were protected against global ischemia due to enhanced IP compared to wild type (WT) and transgenic control (AC3-C) hearts. IKATP was significantly increased, while the negative regulatory dose-dependence of ATP was unchanged in AC3-I compared to WT and AC3-C ventricular myocytes, suggesting that CaMKII inhibition increased the number of functional I(KATP) channels available for IP. We measured increased sarcolemmal Kir6.2, a pore-forming I(KATP) subunit, but not a change in total Kir6.2 in cell lysates or single channel I(KATP) opening probability from AC3-I compared to WT and AC3-C ventricles, showing CaMKII inhibition increased sarcolemmal I(KATP) channel expression. There were no differences in mRNA for genes encoding I(KATP) channel subunits in AC3-I, WT and AC3-C ventricles. The I(KATP) opener pinacidil (100 microM) reduced MI area in WT to match AC3-I hearts, while the I(KATP) antagonist HMR1098 (30 microM) increased MI area to an equivalent level in all groups, indicating that increased I(KATP) and augmented IP are important for reduced ischemic cell death in AC3-I hearts. Our study results show CaMKII inhibition enhances beneficial effects of IP by increasing I(KATP).     

On a Finding of the Polyphagous Pest,Coffee Bean Weevil Araecerus fasciculatus (DeG.) (Coleoptera,Anthribidae), in Natural Habitats of Different Regions of Southern Russia

Entomological Review - One specimen of the coffee bean weevil, Araecerus fasciculatus (DeGeer), was found in the region of Sochi on the Black Sea Coast of Krasnodar Territory. In the recent decade...