Purification and characterisation of glucose (xylose) isomerase from Chainia sp. (NCL 82-5-1)

Glucose (xylose) isomerase is an important enzyme in high fructose syrup industry. The enzyme generally occurs intracellularly and is specific for both glucose and xylose. A rare actinomycete Chainia sp. (NCL 82-5-1) produces extracellular specific glucose and xylose isomerases and an intracellular glucose (xylose) isomerase. The intracellular enzyme is isolated by cell autolysis and purified by preparative polyacrylamide gel electrophoresis. Its properties are studied and compared with those of extracellular specific xylose isomerase. The intracellular enzyme has a molecular weight of 1,58,000 daltons with four equal subunits of 40,700 daltons. The N-terminal amino acid sequence analysis shows Arg at the N-terminal. Diethylpyrocarbonate inhibited the enzyme and the inhibition kinetics study shows the presence of at least 2 essential His residues. The amino acid analysis shows the absence of Cys and a high proportion of hydrophobic and acidic amino acids.     

A comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women in Tamilnadu,India

It is of interest to document data on the comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women. The study consisted of 100 biomass and 100 LPG fuel using women with no smoking habits and other related illness Parameters such as FVC, FEV1, FEV1/FVC, PEFR, FEF25-75%were obtained using the computerized spirometry to assess the pulmonary function in these subjects. The collected data were analyzed using the Student t-test method and Pearson correlation. The exposure index for biomass fuel users is 69.78±27.25 showing high exposure duration during cooking. The parameters for pulmonary functions significantly declined in FVC (42.34±13.6), FEV1 (45.55±15.98), PEFR (34.11±14.78) and FEF25-75% (45.56±23.00) for biomass fuel user. However, this is not true for FEV1/FVC ratio (107.56±16.9). The increase in PFT suggests the restrictive and obstructive patterns of pulmonary diseases. There was a negative correlation between increased duration of cooking and the value of FEV1/FVC (r = -0.2961), FEF25-75% (r = -0.3519) and PEFR (r = -0.2868). Thus, the deformation of pulmonary function due to extended exposure of biomass fuel for cooking women in rural Tamilnadu is shown using parameter features such as high exposure index, overcrowded area and improper ventilated houses.     

Studies on fibre-entrapped whole microbial cells in urea hydrolysis

Microbial cells possessing high urease activity were entrapped in cellulose triacetate fibres, and their capability to hydrolyse urea was evaluated. The activity obtained using these fibres was found to be dependent on the amount of cells entrapped; the best cells-to-carrier ratio was 1:10. Optimum pH and optimum temperature were 7.2 and 60°C respectively, for both the free cells and the immobilized cells, which suggests that the cells are physically bound to the polymer matrix. The effect of flow rate on the extent of conversion and continuous hydrolysis of urea was examined. A flow rate corresponding to a residence time of 1.325 h was found to be satisfactory. The computed half-life of the system was 177.7 h. The potential industrial application is also discussed.     

Microphytoplankton of the Pitchavaram mangals,southeast coast of India: species composition and population density

Species richness of phytoplankton of the Pitchavaram mangals was high. There were 82 species constituted by 67 species of diatoms, 12 species of dinoflagellates and 3 species of bluegreen algae. The diatoms formed the bulk with 72% followed by the dinoflagellates with 15%, in which there were autochthonous (temporary and permanent) and allochthonous forms. Phytoplankton population density exhibited a wide seasonal fluctuation with the minimum during monsoon and the maximum during summer, suggesting the possible differential influence of various environmental factors.     

Identification of volatile compounds from cheek glands of lesser bandicoot rats and assessment of behavioural response for identified compounds

Check gland secretions were collected from sexually mature male and female rats to identify the volatile compounds using gas chromatography linked mass spectroscopy with a modified head space technique. Twenty one volatile fractions including alkanes, aliphatic acids, esters and alcohols were found. Three compounds viz. 3-octen-1-ol (E) (I), cyclopentane undecanoic acid (II) and 2,4,6,8 tetramethyl-l-undecane (III) were present in very high concentrations in both male and female rats. In addition, the estrus female contained another compound, L-alanine, 1,1-dimethyl ethyl ester. On the basis of odour preference tests the compounds I, II and III were found to attract both male and female of the homotypic species. In contrast, the fourth compound present in the female attracts the opposite sex. The results suggest that the volatile fractions have unique function and the level of attraction varies from compound to compound.     

Cripto-1 indirectly stimulates the tyrosine phosphorylation of erb B-4 through a novel receptor

Cripto-1 (CR-1) is a recently discovered protein of the epidermal growth factor family that fails to directly bind to any of the four known erb B type 1 receptor tyrosine kinases. The present study demonstrates that CR-1 indirectly induces tyrosine phosphorylation of erb B-4 but not of the epidermal growth factor-related receptors erb B-2 and erb B-3 in different mouse and human mammary epithelial cell lines. In addition, down-regulation of erb B-4 in NMuMG mouse mammary epithelial cells and in T47D human breast cancer cells, using an anti-erb B-4 blocking antibody or a hammerhead ribozyme vector targeted to erb B-4 mRNA, impairs the ability of CR-1 to fully activate mitogen-activated protein kinase. Finally, chemical cross-linking of 125I-CR-1 to mouse and human mammary epithelial cell membranes results in the labeling of two specific bands with a molecular weight of 130 and 60 kDa, suggesting that the CR-1 receptor represents a novel receptor structurally unrelated to any of the known type I receptor tyrosine kinases. In conclusion, these data demonstrate that CR-1, upon binding to an unknown receptor, can enhance the tyrosine kinase activity of erb B-4 and that a functional erb B-4 receptor is required for CR-1-induced MAPK activation.