The use of immobilized Saccharomyces cerevisiae on radiation crosslinked acrylamide–maleic acid hydrogel carriers for production of ethyl alcohol

Radiation crosslinked acrylamide/maleic acid (AAm/MA) copolymers were prepared by γ-irradiation. They were used in experiments on swelling, diffusion, and immobilization of yeast cells (Saccharomyces cerevisiae) for the production of ethyl alcohol. AAm/MA hydrogels containing different amount of MA, irradiated at different doses, were used for swelling and diffusion studies. The parameters of swelling, diffusional exponents, network constants, diffusion coefficients and percent porosity of the hydrogel/penetrant systems were calculated and evaluated. Yeast cells were immobilized on to the hydrogels by adsorption during multiplication, and ethyl alcohol production by the hydrogels was investigated. Swelling of AAm/MA increased with increase in MA content. Ethyl alcohol production also increased with increasing MA in the hydrogels but decreased with an increase of irradiation dose.     

Zur Abbaubeschleunigung von Pflanzenschutzmittel-Wirkstoffen im Boden

In the current investigation, we report the biosynthesis of silver nanoparticles (Ag NPs) employing extract of Alternaria alternata, which is an eco-friendly process for the synthesis of metallic nanoparticles. Ag NPs were synthesised through the reduction of aqueous Ag⁺ ion using the cell extract of fungus A. alternata in the dark conditions. The synthetic process was relatively fast and Ag NPs were formed within 24 h. UV–visible spectrum of the aqueous medium containing silver ion showed a peak at 435?nm corresponding to the plasmon absorbance of Ag NPs and another peak at 280?nm refers to tyrosine amino acid. The nanoparticles were characterised by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The morphology of nanoparticles is found to be spherical mostly, with ranging size of 27–79?nm; as revealed by SEM. The FTIR spectrum analysis indicated that biomolecules were involved in the synthesis of Ag NPs. The presence of the amino groups is expected to pack differently around the Ag NPs. This in turn will influence the self-assembly of nanoparticles on substrates as well as their stability. The present study demonstrates the possible use of biologically synthesised Ag NPs in the field of agriculture, when A. alternata could be used for simple, nonhazardous and efficient synthesis of Ag NPs.     

Response surface methodological approach for Rhizomucor miehei lipase-mediated esterification of α-terpineol with propionic acid and acetic anhydride

Esterification of α-terpineol with acetic anhydride or propionic acid mediated by Rhizomucor miehei lipase was subjected to a response surface study in order to optimize conditions for maximum esterification. The variables were enzyme/substrate (acid) ratio, α-terpineol concentration and incubation period using lipase from R. miehei. Between acetic anhydride and propionic acid, the former showed better yields at lower enzyme/substrate ratios than the latter. Yields predicted by the models for α-terpinyl propionate and α-terpinyl acetate formation were found to be in agreement with the experimentally determined ones. This revised version was published online in July 2006 with corrections to the Cover Date.     

Studies on Hot Water-soluble and Dilute Alkali-soluble Polysaccharides from the Fruit Body of Mushroom (Psalliota campestris (Linn) Fr.)

The effect of apple polyphenol extract (APE) on the proliferation and invasion of a rat ascites hepatoma cell line of AH109A was examined in vitro. APE suppressed both the hepatoma proliferation and invasion in a dose-dependent manner up to 200 μg/ml. Serum obtained from rats orally given APE also inhibited hepatoma proliferation and invasion when added to the culture medium. Subsequently, the effect of dietary APE on growth and the metastasis of AH109A hepatomas were investigated in vivo. APE reduced the growth and metastasis of solid hepatomas and significantly suppressed the serum lipid peroxide level in rats transplanted with AH109A. APE also suppressed the serum very-low-density lipoprotein + low-density lipoprotein (VLDL + LDL)-cholesterol level. These in vitro and in vivo findings suggest that APE has anti-hepatoma activities.     

Porcine blood cell separation by porous cellulose acetate membranes

Leukocytes were separated from whole porcine blood using laboratory prepared polymeric asymmetric porous membranes from cellulose acetate (CA) and by applying standard blood cell separation methods: centrifugation in a Ficoll solution gradient and in sucrose solution concentration gradient. Leukocytes, obtained by different separation methods were characterised by their quantity, type, viability and growth ability. Membranes prepared by a wet phase inversion process from different cellulose acetate/acetone/water and magnesium chlorate VII systems, were characterised according to: permeability to deionised water, surface morphology and by the determination of the flux of the permeate during the whole porcine blood separation. Cellulose acetate membranes prepared from 300 μm thick cast solution (14.8 wt% of cellulose acetate, 19.9 wt% of water, 2.3 wt% of Magnesium perchlorate, and 63.0 wt% of acetone), have separation characteristics comparable with the standard separation methods; in the dead-end mode filtration, 21.3% of leukocytes from porcine whole blood are separated. The leukocyte number in peripheral blood before separation was 450,000 ml^-1; the number passed through after was 95,000±6620. The main interest of the study was to introduce the CA membrane filters for the continus technological separation of the leukocyte/lymphocytes from animal (= porcine, bovine, horse..) blood. This revised version was published online in June 2006 with corrections to the Cover Date.     

Activation of protein kinase C in neutrophil cytoplasts: Localization of protein substrates and possible relationship with stimulus-response coupling

Treatment of enucleated, granule-free neutrophil cytoplasts with the protein kinase C activator phorbol 12O-myristate-13-acetate (PMA) causes an increased -³²P-incorporation into a variety of polypeptides. Permeabilization of PMA-stimulated, ³²P-labeled cytoplasts by 0.01% digitonin fully releases the majority of these phosphorylated proteins. A statistically significant correlation is found between the extent of PMA-induced activation of generation of Superoxide anion (O⁻₂) and the phosphorylation of a cytosolic polypeptide with an apparent M_r, of 46000, whose -³²P-labeling is also enhanced by the treatment of cytoplasts with 1-oleyl-2-acetylglycerol, the Ca²⁺ ionophore ionomycin or latex beads. Furthermore, treatment of cytoplasts with the protein kinase C inhibitor trifluoperazine markedly inhibits the ³²P-labeling of proteins in the 40000 M_r range, including the 46 kDa polypeptide, and almost totally abolishes the activation of O⁻₂ production by PMA.     

Acetate synthesis from 2 CO2 in acetogenic bacteria: is carbon monoxide an intermediate?

Cultures of Acetobacterium woodii and Clostridium thermoaceticum growing on fructose or glucose, respectively, were found to produce small, but significant amounts of carbon monoxide. In the gas phase of the cultures up to 53 ppm CO were determined. The carbon monoxide production was completely inhibited by 1 mM cyanide. Cultures and cell suspensions of both acetogens incorporated ¹⁴CO specifically into the carboxyl group of acetate. This CO fixation into C₁ of acetate was unaffected by cyanide (1 mM). The findings are taken to indicate that CO (in a bound form) is the physiological precursor of the C₁ of acetate in acetate synthesis from CO₂. The cyanide inhibition experiments support the hypothesis that the cyanide-sensitive carbon monoxide dehydrogenase may serve to reduce CO₂ to CO rather than to incorporate the carbonyl into C₁ of acetate.     

α, βI, βII, δ, and ε Protein Kinase C Isoforms and Compound Activity in the Sciatic Nerve of Normal and Diabetic Rats

Abstract: Defective protein kinase C (PKC) has been implicated in impaired Na⁺,K⁺-ATPase activity in the sciatic nerve of streptozotocin-induced diabetic rats. In the present study, α, βI, βII, γ, δ, and ε isoform-specific antibodies were used in parallel to the measurement of compound PKC activity for the characterization of PKC distribution and isoform expression in sciatic nerves of normal and diabetic rats. To distinguish isoform expression between the axonal and glial compartments, PKC isoforms were evaluated in nerves subjected to Wallerian degeneration and in a pure primary Schwann cell culture. α, βI, βII, δ, and ε but no γ isoforms were detected in sciatic nerve. Similar immunoreactivity was observed in degenerated nerves 3–4 days after transection except for diminished βI and ε species; in Schwann cell cultures, only α, βII, δ, and ε were detected. In normal nerves, two-thirds of PKC compound activity was found in the cytosol and 50% of total enzyme activity translocated to the Na⁺,K⁺-ATPase-enriched membrane fraction with phorbol myristate acetate. Similar redistribution patterns were observed for the immunoreactivity of all isoforms with the exception of δ, which did not translocate to the membrane with phorbol myristate acetate. No abnormality in compound PKC activity, in the immunoreactive intensity, or in the distribution of PKC isoforms could be detected in rat sciatic nerve after 6–12 weeks of diabetes. Thus, defective activation rather than decreased intrinsic PKC activity may occur in diabetic neuropathy.     

Effect of modified glucose uptake using genetic engineering techniques on high-level recombinant protein production in escherichia coli dense cultures

Reduction of acetate excretion using a modified cellular glucose uptake rate was examined. An Escherichia coli strain bearing a mutationin ptsG, a gene encoding enzyme II in glucose phosphotransferase system (PTS), was constructed and characterized. The growth rate of the mutant strain was slower than its parent in glucose defined medium, butwas not affected in complex medium. Experimental results using this mutant strain showed a significant improvement in culture performance in simple batch cultivations due to reduced acetate excretion through the modified glucose uptake. Both biomass and recombinant protein productivity were increased by more than 50% with the ptsG mutant when compared to the parent strain. Recombinant protein productivity by the newly constructed strain at a level of more than 1.6 g/L was attained consistently in a simple batch bioreactor. (c) 1994 John Wiley & Sons, Inc.     

木立芦荟叶内芦荟素的超微细胞化学研究

使用醋酸铅溶液对木立芦荟叶的药用成分芦荟素进行细胞化学定位,在透射电镜下探讨芦荟素产生、转运和贮藏的过程。结果表明:芦荟素由同化薄壁组织产生,质体的类囊体为其合成部位。通过质体膜形成的小泡转移到周围的内质网,以后内质网小泡与质膜融合:或质体小泡直接与质膜融合。通过胞吐作用将芦荟素释放到质膜外,经质外体途径到达维管束的鞘细胞。在鞘细胞中, 芦荟素经内质网小泡转移至内切向壁,由胞间连丝运输到芦荟素细胞的细胞质,最终贮藏在芦荟素细胞的液泡中。