Journal of Environment and Sociobiology

Soma Pal Saha ¹, Samudra Prosad Banik ¹, Aninda Majumder ¹, Ayesha Noor ¹, Karishma Biswas ¹, Nasrin Hasan ¹, Nilanjan Banerjee ¹, Punnag Saha ¹, Raina Das ¹, Sarmistha Halder ¹, Shazia Parveen ¹, Shreya Ghosh ¹, Abdul Mohid ¹, Trishanki Datta ¹, Udita Acharya ¹

Affiliations
1 Department of Microbiology, Maulana Azad College, 8, Rafi Ahmed Kidwai Road, Kolkata-700013, West Bengal, IN

Abstract

Methyl parathion, an organophosphate and cholinesterase inhibitor, is a widely used pesticide. In the present study, fresh vegetables were sampled to enumerate parathion resistant microbes. Nitrite, sulphite and hydrazine levels along with microbial load of the vegetables were determined. Bean, red spinach and coriander contained higher percentages of gram positive bacteria whereas beet ischolar_main and cabbage showed prevalence of gram negative species. Sixty bacterial strains were found to show resistance against 2000/m1 parathion and 5% of these had MIC values above 10000/m1. A gram negative bacterial strain BG023, isolated from bitter gourd surface showed maximal hydrolysis of parathion (MIC 12000/m1). In the absence of other carbon sources, the organism exhibited a faster degradation of parathion with simultaneous utilization of major detectable product p-nitrophenol during the late stationary phase of growth. The gene for parathion hydrolase was found to be plasmid borne since curing with 15 mg/ml SDS resulted in cells which failed to grow in presence of parathion but showed normal growth otherwise. The organism was also resistant to widely used antibiotics like ampicillin, vancomycin, amoxyclav, norfloxacin, bacitracin, etc. After pathogenicity testing, the organism can be used to reduce the load of organophosphate pesticides in agricultural fields.

Keywords

Methyl Parathion, Pesticide Resistant Microorganism, Multiple Antibiotic Resistance, Bioremediation, Plasmid Curing.

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Soma Pal Saha ¹

Affiliations
1 Department of Microbiology, Darjeeling Govt. College, Darjeeling-734101, WB, IN

Abstract

Actinobacteria were isolated from the integument of ant nest soil which seem to play a crucial role in maintaining extraordinary rich and protected environment of the nest. Soil samples were collected from twenty different ant nests of Nagri, Dhajea and Soureni of western part of Darjeeling Himalayan forest areas.The nest soils were of neutral range pH, with high moisture content and appeared as chemically rich in organic carbon, increased available nitrogen and soluble phosphorus. About 10-30% of total microbial population in nest soils was antibiotic synthesizing actinobacteria and appeared as unique and ant-specific. These actinobacteria were efficient to degrade cellulose (77%), starch (33%) and to solubilize tricalcium phosphate (86%) when grown on carboxy methyl cellulose agar, starch agar and Pikovskaya's agar media, respectively. An assumption was made on the basis of observations, that the actinobacteria were absent in the respective non nest soil samples (1m apart from the particular nest location). Hence, the results obtained are promising and nest soil as rich nutrient supplement and the organisms as soil inoculants can be utilized to improve the quality of crop fields of Darjeeling Himalaya.

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