3 Biotech

Deep sea sediment samples of Bay of Bengal (Visakhapatnam) have been analyzed for actinomycetes as an elite source to screen for the production of bioactive metabolites. The actinomycetes strain VSM-30 has an exciting bioactivity profile and was isolated during our systemic screening of marine actinomycetes. It was identified as Streptomyces sparsus based on morphological, physiological, biochemical, and molecular approaches. Response surface methodology regression analysis was carried out to fit the experimental data of each response by the second-order polynomial. The results have proven right interaction among process variables at optimized values of incubation time at 12 days, pH at 8, temperature at 30 °C, concentrations of starch at 1%, and tryptone at 1% and the data have been adequately fitted into the second-order polynomial models. Under these conditions, the responses (zones of inhibition) of plant pathogenic fungi Aspergillus niger, Aspergillus flavus, Fusarium oxysporum, Fusarium solani, and Penicillium citrinum were also matched with experimental and predicted results. Chemotypic analysis of ethyl acetate extract of the strain was done using LC–Q-TOF–MS revealed the presence of bioactive compounds including tryptophan dehydrobutyrine diketopiperazine, maculosin, 7-o-demethyl albocycline, albocycline M-2, and 7-o-demethoxy-7-oxo albocycline in a negative ion mode. The ethyl acetate extract of actinobacterium has been subjected to gas chromatography and mass spectroscopy (GC–MS) revealed the presence of diverse compounds such as dotriacontane, tetracosane 11-decyl-, diheptyl phthalate, 1-hexadecanesulfonyl chloride, l-alanyl-l-tryptophan, phthalic acid ethyl pentyl ester, 4-trifluoroacetoxyhexadecane, and 1H-imidazole 4,5-dihydro-2,4-dimethyl. Hence, the ethyl acetate extract of Streptomyces sparsus VSM-30 may have antibacterial, antifungal, and antioxidant activities due to the presence of secondary metabolites in ethyl acetate extract. The study also supports marine sediment samples of Bay of Bengal, a promising marine ecosystem remained to be explored for new bioactive compounds.

Begomovirus is the largest genus of the family Geminiviridae with wide host range and responsible for a considerable amount of economic damage to many important crops globally. Withania somnifera (Indian ginseng) is an important medicinal plant with high demand in pharmaceutical industries worldwide. During the routine survey in 2019, typical characteristic viral symptoms such as severe leaf curling, downward rolling of the leaves, vein clearing, and poor growth of Withania plants with 17–20% disease incidence were observed in Lucknow, India. Typical symptoms, abundant presence of whiteflies, PCR and RCA based detection indicated the amplification of ~ 2.7 kb and suspected the causal pathogen to be a begomovirus, associated with a betasatellite (~ 1.3 kb). Transmission electron microscopy revealed the presence of twinned particles of ~ 18–20 nm in diameter. Full genome sequencing (2758 bp) of the virus and its analysis showed only 88% sequence identity with the begomovirus sequences present in the database. Hence, based on the nomenclature guidelines we concluded that the virus associated with the present disease of W. somnifera is a novel begomovirus and its name is proposed as Withania leaf curl virus.

RNA-binding protein with serine-rich domain 1, RNPS1, is a global guardian of splicing fidelity and has implications in cervical cancer cell progression. We previously observed elevated RNPS1 expression in cervical cancer cells compared to normal cells. To understand the mechanisms that lead to the dysregulation of RNPS1 expression in cervical cancer cells, we focused on microRNAs. Using an in silico approach, we predicted potential miRNA candidates targeting RNPS1. Among the candidate miRNAs, we found miR-6893-3p as a potential regulator of RNPS1 expression. Interestingly, the expression of miR-6893-3p is downregulated in cervical cancer cells compared to normal cells and its level is negatively correlated with the expression of RNPS1. Further, qPCR, Western blot analysis, and luciferase reporter assay confirmed that miR-6893-3p negatively regulates RNPS1 in HeLa cells. In this regard, overexpression of miR-6893-3p suppresses the endogenous mRNA and protein levels of RNPS1 in HeLa cells. Further investigation revealed that miR-6893-3p mediated regulation of RNPS1 is dependent on the binding of miR-6893-3p to a microRNA response element in the 3’UTR of RNPS1 mRNA. Furthermore, mechanistic analysis showed that targeted negative regulation of RNPS1 by miR-6893-3p occurs via enhanced mRNA degradation. Collectively, our findings establish miR-6893-3p as an important player in the post-transcriptional regulation of RNPS1 in HeLa cells.

Eight exopolysaccharide (EPS) producing metal-removing marine bacteria were screened for mercury (Hg) sorption. Bacillus licheniformis with the highest MIC values and Hg sorption ability was selected for further study. Biosorption of Hg from aqueous solution by Bacillus licheniformis was studied with respect to the metal concentration, adsorbent concentration, pH, different contact times, and in the presence of other metal ions. Under optimum conditions, more than 70% mercury was removed by 25 mg dried biomass of Bacillus licheniformis at pH 7.0 after 1 h of contact time. Freundlich adsorption isotherm was acceptable at studied Hg concentrations as compared to Langmuir isotherm model. Pseudo-second-order kinetic model was found to be more suitable for data presentation in contrast to pseudo-first-order kinetic model. Involvement of external mass transfer was prominent as compared to intraparticle diffusion model. Desorption of Hg was more effective with acids from all the studied eluents, showing 49.36 and 33.8% eluting capacity for 0.1 N HCL and 0.1 N HNO3, respectively. Scanning electron microscopy exhibited altered cell surface morphology of the cells under the influence of mercury. The spectral images of energy dispersive spectroscopy showed the presence of metal ions on the surface of cells.

Plant pathogenic oomycetes cause significant impact on agriculture and, therefore, their management is utmost important. Though conventional methods to combat these pathogens (resistance breeding and use of fungicides) are available but these are limited by the availability of resistant cultivars due to evolution of new pathogenic races, development of resistance in the pathogens against agrochemicals and their potential hazardous effects on the environment and human health. This has fuelled a continual search for novel and alternate strategies for management of phytopathogens. The recent advances in oomycetes genome (Phytophthora infestans, P. ramorum, P. sojae, Pythium ultimum, Albugo candida etc.) would further help in understanding host–pathogen interactions essentially needed for designing effective management strategies. In the present communication the novel and alternate strategies for the management of oomycetes diseases are discussed.