Elcey C Daniel

An efficient and simple method for constructing a genomic DNA library is presented using a TA cloning vector. It is based on sonication cleavage of genomic DNA, blunting of the fragment ends with mung bean nuclease, and addition of a single 3'-deoxyadenylate with Taq DNA polymerase, followed by ligation with a TA vector. This method is useful for improving the quality of genomic libraries for organisms whose genomic DNA is not well digested with restriction enzymes owing to the presence of polysaccharides and/or DNA methylation.

Chromium tolerant fungal strains were isolated from heavy metal contaminated environments and identified using morphological and microscopic observation followed by ribotyping. The microorganisms with the maximum tolerance were analyzed by inoculating each fungus in a PD medium supplemented with hexavalent Chromium salts. The presence of the metal was estimated by the acidic reaction with the 1, 5-diphenylcarbazide method using a spectrophotometer (UV – Vis) at 540 nm. Among all the fungal strains, the most tolerant under maximum enrichment was identified as Paecilomyces lilacinus by a zone of inhibition on the PDA medium. The effect of environmental parameters like pH and temperature on the growth and heavy metal removal also were analyzed. Among the fungal strains, Aspergillus niger, A. terreus, and Paecilomyces lilacinus could tolerate Chromium (VI) toxicity up to 800 mgL-1. All the fungi were able to completely remove the heavy metal Cr (VI) at the concentration of 10mg/L, where...

Nanotechnology is the engineering of functional systems at the molecular scale. The technology can be used to treat cancer by the application of hyperthermia to magnetic nanoparticles and is found to be effective in cancer repression. Iron oxide nanoparticles were synthesized by co-precipitation method. Synthesized nanoparticles were ranging from 10 to 20nm size with Iron concentration of 6 μg. Cancer cell lines, A549 and HeLa, were subjected to hyperthermia treatment and the effect of iron oxide nanoparticles was analysed by Microscopic and Spectroscopic analysis, along with MTT assay in order to check the toxicity of the nanoparticles. Viability of the cells with respect to the concentration of the nanoparticles was determined. Under the influence of the electromagnetic field, iron oxide nanoparticles reduced the viability of the cancer cell lines ie., 44% after 5 minutes, 31% and 29% after 10 minutes of exposure.

Nanotechnology is a progressive technology interdisciplinary with physics, chemistry, biology, material science and medicine. Nanoparticles are usually 0.1 to 100 nm in each spatial dimension and chemical as well as biological process supports their synthesis. The usage of toxic chemicals used in the physical and chemical synthesis of nanoparticles is a factor which limits its biomedical applications. Hence, methods for the synthesis of nanoparticles that are reliable, nontoxic and eco-friendly are of vital importance. Nanoparticle synthesis using microorganisms is one of the possibilities to attain this goal (Narayanan et al., 2010). Microbial synthesis is one of such processes, a green chemistry approach that interlinks nanotechnology and microbial ISSN: 2319-7706 Volume 3 Number 8 (2014) pp. 408-417 http://www.ijcmas.com

A microbial consortium that can utilize alpha-hexachlorocyclohexane (alpha-HCH) as a sole source of carbon and energy was isolated from soil and sewage through a novel technique involving an initial enrichment in a glass column reactor followed by a shake flask enrichment. This consortium took 14 days to completely mineralize 5 and 10 microg mL(-)(1) alpha-HCH in mineral salts medium in shake flasks. The degradative ability of this consortium improved very markedly on acclimation by successive and repeated passages through media containing increasing concentrations of alpha-HCH. The acclimated consortium could degrade 100 microg mL(-)(1) of alpha-HCH within 72 h at a degradation rate of 58 microg mL(-)(1) day(-)(1) with concomitant release of stoichiometric amounts of chloride. Accumulation of any intermediary metabolites was not detected in the culture broth as tested by TLC and GC, implying complete mineralization of the substrate. The acclimated consortium contained eight bacterial strains and a fungus. The individual strains and the different permutations and combinations of them, however, were able to utilize only 10 microg mL(-)(1) of alpha-HCH. Mesophilic temperatures (20-30 degrees C) and near-neutral pH (6.0-8.0) were most favorable for alpha-HCH degradation. Among the auxiliary carbon sources tested, ethanol, benzoate, and glucose (at higher concentrations) retarded the degradation of alpha-HCH, whereas the addition of cellulose, sawdust, and low concentrations of glucose (<200 microg mL(-)(1)) and acetone enhanced the rate of degradation.

Widespread contamination of the environment, globally, has been caused by extensive and indiscriminate use of hexachlorocyclohexane (HCH) as an insecticide since the 1940s, threatening the biota including humans, and there is an urgent need to eliminate it, preferably through bioremediation technologies. A gamma-HCH-degrading microbial consortium was isolated by enrichment of a soil sample from a sugar cane field having a long history of technical grade HCH application. On acclimation the degrading ability improved substantially. The consortium, which took 10 days to degrade 25 microg mL(-1) of gamma-HCH, initially could mineralize even 300 microg mL(-1) of the substrate within 108 h on acclimation. With 300 microg mL(-1) substrate, the rate of degradation, as calculated for the early exponential phase, was 216 microg mL(-1) day(-1), the highest reported so far. An amount of 400 microg mL(-1) of gamma-HCH, however, was mineralized partially with only 78% Cl(-) release. No apparent accumulation of intermediary metabolites was observed up to 300 microg mL(-1) substrate, indicating a fast rate of mineralization. Aeration, mesophilic temperatures (20-35 degrees C), and near neutral pH (6.0-8.0) were favorable conditions for degradation. The presence of glucose at 1000 microg mL(-1) retarded the degradation, whereas cellulose and sawdust at 1600 microg mL(-1) and glucose at 100 microg mL(-1) did not show any marked effect. The consortium also mineralized alpha-, beta-, and delta-HCH efficiently. The consortium consisted of nine bacterial strains and a fungal strain, and individually they were able to degrade 10 microg mL(-1) of gamma-HCH. This mixed culture holds high potential for deployment in bioremediation of HCH-contaminated soils, waste dumpsites, and water bodies.

An efficient and simple method for constructing a genomic DNA library is presented using a TA cloning vector. It is based on sonication cleavage of genomic DNA, blunting of the fragment ends with mung bean nuclease, and addition of a single 3'-deoxyadenylate with Taq DNA polymerase, followed by ligation with a TA vector. This method is useful for improving the quality of genomic libraries for organisms whose genomic DNA is not well digested with restriction enzymes owing to the presence of polysaccharides and/or DNA methylation.