Characterisation of PM(10), PM(2.5) and benzene soluble organic fraction of particulate matter in an urban area of Kolkata, India.

In this study, the relationship between inhalable particulate (PM(10)), fine particulate (PM(2.5)), coarse particles (PM(2.5 - 10)) and meteorological parameters such as temperature, relative humidity, solar radiation, wind speed were statistically analyzed and modelled for urban area of Kolkata during winter months of 2003-2004. Ambient air quality was monitored with a sampling frequency of twenty-four hours at three monitoring sites located near traffic intersections and in an industrial area. The monitoring sites were located 3-5 m above ground near highly trafficked and congested areas. The 24 h average PM(10) and PM(2.5) samples were collected using Thermo-Andersen high volume samplers and exposed filter papers were extracted and analysed for benzene soluble organic fraction. The ratios between PM(2.5) and PM(10) were found to be in the range of 0.6 to 0.92 and the highest ratio was found in the most polluted urban site. Statistical analysis has shown a strong positive correlation between PM(10) and PM(2.5) and inverse correlation was observed between particulate matter (PM(10) and PM(2.5)) and wind speed. Statistical analysis of air quality data shows that PM(10) and PM(2.5) are showing poor correlation with temperature, relative humidity and solar radiation. Regression equations for PM(10) and PM(2.5) and meteorological parameters were developed. The organic fraction of particulate matter soluble in benzene is an indication of poly aromatic hydrocarbon (PAH) concentration present in particulate matter. The relationship between the benzene soluble organic fraction (BSOF) of inhalable particulate (PM(10)) and fine particulate (PM(2.5)) were analysed for urban area of Kolkata. Significant positive correlation was observed between benzene soluble organic fraction of PM(10) (BSM10) and benzene soluble organic fraction of PM(2.5) (BSM2.5). Regression equations for BSM10 and BSM2.5 were developed.

Measurements of inhalable particles<10 microm (PM(10)) and total suspended particulates (TSP) concentrations along the north-south corridor, in Kolkata, India.

The 24-hour concentrations of total suspended particulate matter (TSP) and respirable suspended particulates (PM(10)) were monitored during March 2003 to February 2004 from a network of 15 sampling stations along a populated urban corridor of Kolkata City in India. The air samplers were placed at a distance 20-200 m from roadways and their height from ground level was within 3 to 5 m. It was also insured that from any obstacle to the airflow was at least 30 cm away. Over the study area, the monthly average concentrations of TSP and PM(10) were found to be 200.3 +/-93.1 microg/m(3) and 95.8+/-67.5 microg/m(3), respectively, while the 24-hour average concentrations were in the range of 17--456 microg/m(3) and 15--291 microg/m(3), respectively. The higher average values at particular stations reflected the closeness of those to heavy road traffic. With regards to the temporal variations, higher concentrations were observed during winter and lower concentrations during monsoon. Statistical analysis of the sampling data was conducted to obtain general characteristics of the particulate pollution and to investigate the effects of traffic volume and meteorological factors on the pollution level. TSP and PM(10) concentrations were found to be highly correlated with each other at all the sampling stations. There were clear associations between TSP and PM(10) data set at all the measured 15 stations and on average, PM(10) was 52% of the total TSP concentration.

Cloning, characterization, and expression studies in Escherichia coli of growth hormone cDNAs from Indian zebu cattle, reverine buffalo, and beetal goat.

The growth hormone cDNAs from three different economically important animal species of indian origin viz., indian zebu cattle (Bos indicus), indian reverine buffalo (Bubalus bubalis), and beetal goat (Capra hircus) were isolated by the RT-PCR technique. The amplified product was then cloned into phagemid pBluescriptIIKS- and the nucleotide sequence of the entire 573 base coding region for each product was determined. The genetic sequences as well as the translated protein sequence of these ruminant species were compared to that of closely related species like taurine cattle (Bos taurus) and sheep (Ovis aries). A very high degree of nucleotide sequence homology, ranging between 97-98%, was observed. Subsequently, the buffalo and goat cDNAs were used for expression studies in Escherichia coli. Very low levels of expression resulted when the growth hormone cDNAs were directly placed under the strong E. coli (trc) or phage (T7) promoters with the approximate level being less than 0.1% and 1% of the intracellular E. coli proteins, respectively. The nearly 10-fold enhancement of the level of expression as observed was attributable to the nature of the untranslated leader sequence donated by the individual expression element. High level (about 20% of soluble E. coli protein) expression of buffalo/goat growth hormone was achieved as a fusion protein with glutathione-s-transferase (GST) in pGEX-KT. Further, although attempts at converting the GST-GH fusion protein system to a two-cistronic gene expression system were unsuccessful, the utilization of a short synthetic first cistron in the two-cistronic mode of expression resulted in high levels (approximately 30% of soluble protein cell fraction) of GH polypeptide with a native N-terminus in E. coli for all three cDNAs.

Bovine chymosin: production by rDNA technology and application in cheese manufacture.

Bovine chymosin, an aspartyl protease extracted from abomasum of suckling calves, is synthesized in vivo as preprochymosin and secreted as prochymosin which is autocatalytically activated to chymosin. Chymosin is bilobular, with Asp 32 and Asp 215 acting as the catalytic residues. Chymosin A and chymosin B have pH optima of 4.2 and 3.8, respectively, and act to initiate milk clotting by cleaving kappa-casein between Phe 105 and Met 106. The gene encoding chymosin has been cloned and expressed in suitable bacteria and yeast hosts under the control of lac, trp, trp-beta, gly A genes, and serine hydroxymethyl-transferase promoters. Protein engineering of chymosin has also been attempted. A number of companies are now producing recombinant chymosin for commercial use in cheese manufacture.