Presence of pesticide-tolerant microorganisms in high-altitude pristine lakes within Singalila Ridge of the Himalayas.

This is the first report on high pesticide tolerance displayed by the microbiota isolated from the sediments of two high-altitude lakes, located in the Singalila National Park, Singalila Ridge of the Himalayas. Given the remote location of these lakes, direct exposure to chemical pesticides is highly unlikely. However, the high tolerance to commonly used pesticides exhibited, i.e. up to 250 mg/ml, suggests repeated exposure and contamination of the lakes. Microbial growth in the presence of varying concentrations of the pesticides, namely, emamectin benzoate, thiamethoxam, quinalphos, deltamethrin, spiromesifen, flubendiamide, monocrotophos, fipronil, fenazaquin and phorate, was tested. Results showed resistance to all pesticides except fenazaquin and fipronil, up to 250 mg/ml. For the latter two, tolerance was displayed up to a concentration of 40 mg/ml. Tolerance may potentially result from the transport and deposition of pesticides from nearby locations, particularly the tea plantations of Darjeeling and Eastern Nepal. This may create great ecological risks as these lakes are an important water source for endemic wildlife of this protected area. They also hold great significance to the religious sentiment of the local tribes who worship these lakes as sacred. The study highlights the need for monitoring pesticide contamination in such pristine high-altitude environments and the mechanisms of long-range pollutant transport.

Photosynthetic organs of wild Indian tea tree are rich in patchouli components: a GC-MS based metabolomics.

Gas chromatography-mass spectrometry is an essential tool for metabolomics. In this research we have selected photosynthetic organs- leaf and sepal of a wild Indian tea tree from north-east India to study wild tea metabolites. The result of this study reveals that photosynthetic parts of wild Indian tea tree are rich in 'patchouli' components unlike established cultivated varieties which are known to be rich in polyphenols or flavonoids. Twenty six compounds were detected in sesquiterpene rich leaf while nineteen were detected in the waxy sepal. The remarkable outcome of this study is presence of fourteen 'patchouli' compounds including patchouli alcohol as the major compound (44.81% in leaf and 19.59% in sepal) which can promote this plant to a top-notch position in fields of botany, pharmaceuticals and essential oil industry by occupying the throne of patchouli.

Characterization of a mercury tolerant strain of Staphylococcus arlettae from Darjeeling hills with an account of its antibiotic resistance pattern and metabolome.

Mercury (Hg) is a ubiquitous heavy metal grouped with the top ten most toxic pollutants affecting both human and environmental health. Consequently, mercury contamination due to anthropogenic interference has become a rising global concern. The bacterial strain MTD10A was isolated from soil samples collected over the Darjeeling hills. Heavy metal tolerance study conducted exhibited considerable tolerance to mercury by this bacterial isolate at unprecedented concentrations of up to 0.1 mg/mL of HgCl2. Biochemical characterization and molecular identification via 16S rRNA sequencing identified this highly tolerant bacteria as a strain of a Coagulase Negative Staphylococcus arlettae. This study also maps the resistance pattern of MTD10A against clinically relevant antibiotics and contains a broad assessment of the metabolomic profile of the bacteria achieved via GC-MS. Tolerance of MTD10A to such excessive levels of mercury shown in our study suggests the possibility of a promising candidate for bioremediation in heavily mercury contaminated areas.