Pritesh Parmar

Withania somnifera (Ashwagandha): a Novel Source of L-asparaginase

Different parts of plant species belonging to Solanaceae and Fabaceae families were screened for L-asparaginase enzyme (E.C.3.5.1.1.). Among 34 plant species screened for L-asparaginase enzyme, Withania somnifera L. was identified as a potential source of the enzyme on the basis of high specific activity of the enzyme. The enzyme was purified and characterized from W. somnifera, a popular medicinal plant in South East Asia and Southern Europe. Purification was carried out by a combination of protein precipitation with ammonium sulfate as well as Sephadex-gel filtration. The purified enzyme is a homodimer, with a molecular mass of 72 +/- 0.5 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion chromatography. The enzyme has a pH optimum of 8.5 and an optimum temperature of 37 degrees C. The Km value for the enzyme is 6.1 x 10(-2) mmol/L. This is the first report for L-asparaginase from W. somnifera, a traditionally used Indian medicinal plant.

Optimization of Process Parameters for Cellulase Production by Bacillus licheniformis MTCC 429 using RSM and Molecular Characterization of Cellulase Gene

World is threaten to energy crisis which has advances research in bioenergy and specifically development of biofuels to replace petroleum products have increased the use of microbial enzyme like cellulases and xylanases as well as amylases for generation of reducing sugars for their conversion into bioethanol. Extensive research has been carried out in this view but alkaline cellulase production and molecular characterization is not studied in detail so far, this study will aid to achieve it. Optimization of fermentation parameters for production of cellulase was evaluated with the help of Response Surface Methodology (RSM) a statistical design, initial pH (9), moisture ratio (1:1) and incubation time (72 h) (run no.4) were found to be ideal parameters for optimum production of cellulase, substrate Jatropha seed cake without any pre-treatment was found to be an ideal source for cellulase production by Bacillus licheniformis under solid state fermentation. Cellulase gene of size 786 bp was isolated later using PCR techniques, confirmed with sequence analysis and ligated to pRSET A vector for the transformation to E. coli DH5α. Positive clones were identified and sequenced to justify the cloning. Sequence of Bacillus licheniformis endo-β-1,4-glucanase (Cel12A) gene showed 100% similarity with endoglucanase gene sequence from Bacillus licheniformis ATCC 14580 genome, shows successful cloning of Cel12A gene into pRSET A vector.

Nickel accumulation by Colocassia esculentum and its impact on plant growth and physiology

The remediation of heavy metal-contaminated sites using plants presents a promising alternative to current methodologies. In this study, the potential of Colocassia esculentum for Nickel (Ni) accumulation was determined. C. esculentum plants exposed to Ni, demonstrated capability to accumulate on average, more in shoots as compared to roots, suggesting better translocation of Ni from root to shoot. High metal content in soil caused reduction in growth parameters and an increase in oxidative stress. Under heavy metal stress, an increase in catalase, peroxidase, ascorbic acid and proline were observed in the roots along with some anatomical changes. Lipid peroxidation showed a slight increase by Ni treatment along with some anatomical changes in the root. This work demonstrates that metal induced oxidative stress occurs by the presence of heavy metals at higher concentrations. It also suggests that superior antioxidative defenses, particularly catalase activity, may play an important role in C. esculentum. The outcome of this study corroborate that C. esculentum is a suitable candidate for the phytoremediation of Ni contaminated soil and could be considered as a potential Ni hyperaccumulator plant species.

Isolation of NBS-LRR class resistant gene (I2 gene) from tomato cultivar Heamsona

Three races of Fusarium oxysporum f. sp. lycopersici race 1, 2 and 3 are identified depending on the avirulence protein or effector protein secreted by fungal pathogen during the host colonization in tomato. These effector proteins are recognized by the host innate immune system based on R gene expressions that are I1, I2 and I3 in tomato for each races. Amongst the three, I2 protein has been cloned and characterized for the incompatibility against race 2 type of the pathogens. In India race 1 type of F. oxysporum f. sp. lycopersici observed commonly which require presence of I1 gene in tomato plant for the incompatibility reactions but in the present study, I2 gene was partially isolated from the tomato cultivar Heamsona and observed to be resistance against race 1 type of pathogen. Keywords: Fusarium wilt, race, R-gene, resistance, tomato. African Journal of Biotechnology Vol. 12(42), pp. 6076-6078