Leaching of copper converter slag withAspergillus niger culture filtrate

Leaching of copper converter slag of M/s Hindustan Copper Ltd, Ghatshila (Bihar, India) was carried out usingAspergillus niger culture filtrate. The effects of the duration of leaching, temperature, pulp density and the addition of hydrochloric acid were studied.A. niger culture filtrate solubilized metals from the converter slag at levels of 18.70% copper, 7.40% nickel and 4.00% cobalt. Addition of hydrochloric acid was found to improve copper, nickel and cobalt solubilization to 46.52, 27.90 and 37.96%, respectively. HPLC analysis of the fungal culture filtrate revealed the presence of succinic and citric acids. Therefore, leaching of the slag was also carried out with matching concentrations of these organic acids individually as well as with both mixed together. Results are discussed.     

A microplate assay for DNA damage determination (fast micromethod).

A rapid and convenient procedure for DNA damage determination in cell suspensions and solid tissues on single microplates was developed. The procedure is based on the ability of commercially available fluorochromes to interact preferentially with dsDNA in the presence of ssDNA, RNA, and proteins at high pH (>12.0), thus allowing direct measurements of DNA denaturation without sample handling or stepwise DNA separations. The method includes a simple and rapid 40-min sample lysis in the presence of EDTA, SDS, and high urea concentration at pH 10, followed by time-dependent DNA denaturation at pH 12.4 after NaOH addition. The time course and the extent of DNA denaturation is followed in a microplate fluorescence reader at room temperature for less than 1 h. The method requires only 30 ng DNA per single well and could conveniently be used whenever fast analysis of DNA integrity in small samples has to be done, e.g., in patients' lymphocytes after irradiation or chemotherapy (about 3000 cells per sample), in solid tissues or biopsies after homogenization (about 25 microg tissue per well), or in environmental samples for genotoxicity assessment.     

Aerobiology, biodiversity and chemistry of plant trichomes in the tropics at Bodh Gaya, India – a biopollutant and the suspected human allergen

Aerobiology, diversity and chemistry of some air borne plant trichomes were studied at Magadh University campus, Bodh Gaya, India between September 1995 and August 1996. Thirty-three morphotypes of trichomes were tapped using a Gravity Air sampler. The different types of trichomes showed pronounced seasonality in their distribution pattern. The simple non-septate trichomes of grasses were predominant throughout the year. The other commonly observed trichomes were comparable to that of Chrysanthemum, Tridax, Solanum, Amaranthus and Martynia. Trichomes. The Shannon diversity index of trichomes fluctuated widely (1.063–2.867) during different months of the year. This suggests that seasonality had definite bearing on the composition of aerobiota. Relative humidity was found to play greater role in the case of a number of morphotypes (67%), diversity index (50%) and species richness (61%) but in the case of index of dominance (62%), rainfall played a greater role at P < 0.01 level. The trichomes of a few selected plant species, the pollen grains of which are reported allergens, were chemically analysed by collecting them in bulk. They were found to be fairly rich in their total protein (9.58 to 93.60 mg/g) and carbohydrate (10.0 to 20.20 mg/g) contents.