Influence of carbon and nitrogen sources on glutathione catabolic enzymes inCandida albicans during dimorphism

The effect of carbon sources, glucose and sucrose, and nitrogen sources such as ammonia, glutamate andl-citrulline on the activities of glutathione metabolic enzymes has been studied. Yeast and mycelial cells were used to identify changes in activity levels of glutathione reductase (GSSGR), glutathione transferase (GST), glutathione peroxidase (GPX) and -glutamyl transpeptidase (GGT). Enzyme activities from cells grown in sucrose media were lower than in glucose media regardless of the enzyme tested, morphological form, or the growth interval. In all enzymes except GST, activity was higher in yeast form than in mycelia, regardless of nitrogen source, with lower activity from 24 to 72 h than at 96 h. In citrulline media, yeast form showed the maximum GST, GGT, and GPX activity. In ammonia-amended media, mycelia showed maximum activity in GGT, whereas in glutamate media, mycelia showed the maximum activity in GST. Also, the type of nitrogen source had no effect on GPX activity in the mycelial form. Finally, changing the nitrogen source showed no significant effect on GSSGR activity, either in the yeast or mycelial form.     

Copper influenced changes of lipid metabolism in the tissues of freshwater teleost Labeo rohita (Hamilton).

Modulations in the lipid metabolism in the gill, liver, muscle and brain of freshwater teleost Labeo rohita exposed to 1, 2 and 3 days to lethal (1.2 mg/l) and 1, 15 and 30 days to sublethal (0.24 mg/l) concentrations of copper were studied. The total lipids decreased and there was an increase in the free fatty acids, glycerol and lipase activity in the organs studied at lethal concentration of copper. The degree in these shifts increased over time of exposure (1 less than 2 less than 3 days). In sublethal concentration, the levels of total lipids, free fatty acids, glycerol and lipase activity increased in all the four organs and the shifts followed two different trends during the exposure periods, 1 less than 15 less than 30 days in total lipids and 1 greater than 15 greater than 30 days in the other parameters. Among the organs, in both concentration media the changes in the lipid metabolism were in the order liver greater than gill greater than muscle greater than brain.     

Determination of cobalt in urine by gas chromatography—mass spectrometry employing nickel as an internal standard

A gas chromatographic—mass spectrometric method for the determination of cobalt in biological materials employing stable enriched ⁶²Ni as an internal standard and using lithium bis(trifluoroethyl)dithiocarbamate as a chelating agent is described. The method involves the addition of a known amount (1 μg) of ⁶²Ni to the sample, the formation of the chelate and the determination by selected-ion monitoring of the m/z ratio, which corresponds to . No appreciable memory effect was observed, and an acceptable dynamic range of 100 was found. There was good agreement between the cobalt concentration values determined by gas chromatography—mass spectrometry and electrothermal atomic absorption spectrometry. The present method has high sensitivity and can be used for the quantitation of cobalt at concentrations as low as 1 μg/l. The use of enriched ⁶²Ni circumvents the problem caused by endogenous nickel and simultaneously provides data on the nickel concentration in the biological sample without any additional experimental effort.     

An actidione resistantCandida tropicalis from custard apple juice

An actidione resistant yeast,Candida tropicalis, was isolated from fermenting custard apple juice. Though a slight inhibition of growth was observed on the first day with 5000 ppm of actidione, growth was equal to control after one week. Sorbic acid at 500 ppm and above inhibited the growth of this yeast while sodium benzoate and potassium metabisulphite were unable to suppress the growth even at 1000 ppm. Fermentation and assimilation of different carbon sources were delayed in the presence of 1000 ppm of actidione suggesting the disruption of protein synthesis by actidione. Contribution no. 985.     

Aquatic oligochaeta from among the roots of eichhornia crassipes solms

The paper records the presence of sixteen species of aquatic oligochaetes, belonging to the Aeolosomatidae (1 species). Naididae (13 species) and Tubificidae (2 species), living in association with the floating roots of the water hyacinth, Eichhornia crassipes Solms., from a tank in Vizianagaram town in Andhra Pradesh, India. Of these, Aeolosoma hyalinum Bunke, 1967 and Dero obtusa D'Udekem, 1855 are new records for the Indian sub-continent.     

Agrobacterium-mediated transient GUS gene expression in buffel grass (Cenchrus ciliaris L.)

The study was conducted to standardize a protocol for Agrobacterium-mediated genetic transformation of buffel grass (Cenchrus ciliaris L.). Embryogenic calli, produced from one-year-old mature seeds of buffel grass, were used as target cells for Agrobacterium-mediated transformation. A. tumefaciens strain LBA4404, harbouring pCAMBIA-1301 or pCAMBIA-2301, was used for co-cultivation with embryogenic calli from three genotypes (IG-3108, IG-9757 and IG-97101). Co-culturing of calli with Agrobacterium for 30 minutes, followed by co-cultivation with 0.1 mM acetosyringone for 3 days was found to be optimum for maximum transformation efficiency. Presence of acetosyringone during co-cultivation was found to be necessary for transformation. Transient GUS (beta-glucuronidase) gene expression was used to monitor T-DNA delivery into the target cells. Significant genotypic variations in response to transformation were observed among the tested genotypes. A very high frequency (63.3%) of GUS gene expression was obtained following Agrobacterium-mediated gene transfer into embryogenic calli. The standardized protocol would be useful for Agrobacterium-mediated genetic transformation of buffel grass with genes of agronomic importance.     

Pancreatic anticancer activity of a novel geranylgeranylated coumarin derivative

A series of hydroxycoumarin derivatives has been synthesized and evaluated against human pancreatic PANC-1 cancer cells under nutrient-deprived conditions. Several compounds exhibited 100% preferential cytotoxicity at low micromolar concentrations under nutrition starvation, and showed no cytotoxicity under nutrient-rich conditions. In this study, a novel geranylgeranylated ether coumarin derivative 9 was found to exhibit the highest cytotoxic activity of 6.25 μM within 24h. The preferential anti-tumor activity exhibited by compound 9 against PANC-1 under low oxygen and nutrient environment illustrates its great potential as a promising lead structure for the development of novel agents to combat pancreatic cancer.     

Delineating the Specific Influence of Virus Isoelectric Point and Size on Virus Adsorption and Transport through Sandy Soils

Many of the factors controlling viral transport and survival within the subsurface are still poorly understood. In order to identify the precise influence of viral isoelectric point on viral adsorption onto aquifer sediment material, we employed five different spherical bacteriophages (MS2, PRD1, Qβ, X174, and PM2) having differing isoelectric points (pI 3.9, 4.2, 5.3, 6.6, and 7.3 respectively) in laboratory viral transport studies. We employed conventional batch flowthrough columns, as well as a novel continuously recirculating column, in these studies. In a 0.78-m batch flowthrough column, the smaller phages (MS2, X174, and Qβ), which had similar diameters, exhibited maximum effluent concentration/initial concentration values that correlated exactly with their isoelectric points. In the continuously recirculating column, viral adsorption was negatively correlated with the isoelectric points of the viruses. A model of virus migration in the soil columns was created by using a one-dimensional transport model in which kinetic sorption was used. The data suggest that the isoelectric point of a virus is the predetermining factor controlling viral adsorption within aquifers. The data also suggest that when virus particles are more than 60 nm in diameter, viral dimensions become the overriding factor.