Browsing by Author "Debashis Dutta"

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Carotenoid biosynthetic pathways are regulated by a network of multiple cascades of alternative sigma factors in Azospirillum brasilense Sp7
(American Society for Microbiology, 2016) Ashutosh Kumar Rai; Ashutosh Prakash Dubey; Santosh Kumar; Debashis Dutta; Mukti Nath Mishra; Bhupendra Narain Singh; Anil Kumar Tripathi
Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A. brasilense caused reduction in carotenoid content, suggesting their involvement in carotenoid synthesis. However, the effect of crtE1 deletion was more pronounced than that of crtE2 deletion. Out of the five paralogs of rpoH in A. brasilense, overexpression of rpoH1 and rpoH2 enhanced carotenoid synthesis. Promoters of crtE2 and rpoH2 were found to be dependent on RpoH2 and RpoE1, respectively. Using a two-plasmid system in Escherichia coli, we have shown that the crtE2 gene of A. brasilense Sp7 is regulated by two cascades of sigma factors: one consisting of RpoE1and RpoH2 and the other consisting of RpoE2 and RpoH1. In addition, expression of crtE1 was upregulated indirectly by RpoE1 and RpoE2. This study shows, for the first time in any carotenoid-producing bacterium, that the regulation of carotenoid biosynthetic pathway involves a network of multiple cascades of alternative sigma factors. © 2016, American Society for Microbiology. All Rights Reserved.
Characterisation of bioactive metabolites from endophytic bacterial isolate
(Research Journal of BioTechnology, 2017) Moti Lal; Neelam Tia; Shiv Kr. Verma; Debashis Dutta; Debnath Das Mira
The aim of this study was to isolate and identify endophytic bacteria from stems and root of adhathoda beddomei and to evaluate their antibacterial and antifungal properties. The present investigation was carried out to analyse the morphological, physiological, biochemical and cultural characteristics diversity in the bacterial endophyte of two species of adhathoda beddomei, a total of 10 bacterial. Endophytes were isolated from tissues, stem, root. The antimicrobial and antifungal activity was tested against Escherichia coli. Pseudomonas aeroginosa, Staphylococcus aureus, Penicillium chrysogenum, Lactobacillus lactis, Bacillus subtilis and Candida albican. Minimum inhibitory concentration (MIC) of crude extract against performed microorganisms was determined. NMR, FTIR, element and mass analysis of fractionated crude extract were carried out for empirical formula and functional group. © 2017, Research Journal of BioTechnology. All rights reserved.
Comparative Study of Moisture Dynamics in the Soils of Two Different Sugarcane-Based Cropping System (Viz: Intercropping and Sole) in Western Indo-Gangetic Plains of Uttar Pradesh
(Springer, 2025) Shivam C. Singh; Richa Raghuvanshi; Satendra Kumar; Debashis Dutta; Jagannath Pathak; U. P. Shahi; B. P. Dhyani; Mahendra Pratap Singh
Soil water plays important role in soil–plant consortium in which plant absorbs from soil. Thus, soil acts as reservoir of water towards its proper growth. Sugarcane among the cash crop needs large quantity of water during its life-cycle. Hence, dynamics of water in soil were studied from two major sugarcane-based cropping pattern (intercropping and sole) at three depths at 15 cm interval (0–45 cm). The result invoked that soils were sandy-loam to sandy-clay-loam textured under different cropping system and depth. The increase in the clay content down the depth elevates the holding capacity of water via clogging the pore spaces under all the cropping system and depth. Therefore, the difference in behaviour is mainly attributed to the difference in cropping system only. Intercropping system showed high bulk density, low organic carbon, high clay:carbon ratio, high porosity and high E.C. compared to the sole sugarcane-based cropping system. The moisture dynamics under all cropping system behaved quadratically and attains minimum value. The other moisture parameter derived from the moisture loss curve indicates that intercropping has high moisture loss, high instaneous loss and low average moisture content. © The Author(s), under exclusive licence to The National Academy of Sciences, India 2025.