Browsing by Author "Mehrotra, Rajesh"

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Association of Rhizospheric/Endophytic Bacteria with Plants: A Potential Gateway to Sustainable Agriculture
(Greener Journals, 2013) Jha, Prabhat N.; Mehrotra, Rajesh
Application of associative bacteria for sustainable agriculture holds immense potential. These bacteria are known to enhance growth and yield of plants by fixing atmospheric nitrogen, solubilization of phosphate, production of phytohormones and siderophores, possession of antagonistic activity as well as reducing the level of stress ethylene in host plants. Colonization of these bacteria can be tracked by tagging them with certain molecular markers such as β-glucuronidase (gus) or green fluorescent protein (gfp) followed by electron microscopy or laser scanning confocal microscopy. Associative bacteria and endophytes may express genes differentially to colonize and establish the plant interior. They may also use ‘quorum sensing’ molecules for colonization process. Present review aims to highlight various plant growth promoting properties, ecology and updates of molecular mechanisms involved in interaction between associative bacteria and plants as well as immune responses triggered by these bacteria in plants.
Association of Rhizospheric/Endophytic Bacteria with Plants: A Potential Gateway to Sustainable Agriculture
(Greener Journals, 2013) Jha, Prabhat N.; Mehrotra, Rajesh
Application of associative bacteria for sustainable agriculture holds immense potential. These bacteria are known to enhance growth and yield of plants by fixing atmospheric nitrogen, solubilization of phosphate, production of phytohormones and siderophores, possession of antagonistic activity as well as reducing the level of stress ethylene in host plants. Colonization of these bacteria can be tracked by tagging them with certain molecular markers such as β-glucuronidase (gus) or green fluorescent protein (gfp) followed by electron microscopy or laser scanning confocal microscopy. Associative bacteria and endophytes may express genes differentially to colonize and establish the plant interior. They may also use ‘quorum sensing’ molecules for colonization process. Present review aims to highlight various plant growth promoting properties, ecology and updates of molecular mechanisms involved in interaction between associative bacteria and plants as well as immune responses triggered by these bacteria in plants.
Biodiesel production through lipase catalyzed transesterification: An overview
(Elsiever, 2010) Jha, Prabhat N.; Mehrotra, Rajesh
Recently, with the global shortage of fossil fuels, excessive increase in the price of crude oil and increased environmental concerns have resulted in the rapid growth in biodiesel production. The central reaction in the biodiesel production is the transesterification reaction which could be catalyzed either chemically or enzymatically. Enzymatic transesterification has certain advantages over the chemical catalysis of transesterification, as it is less energy intensive, allows easy recovery of glycerol and the transesterification of glycerides with high free fatty acid contents. Limitations of the enzyme catalyzed reactions include high cost of enzyme, low yield, high reaction time and the amount of water and organic solvents in the reaction mixture. Researchers have been trying to overcome these limitations in the enzyme catalyzed transesterification reaction. This paper is meant to review the latest development in the field of lipase catalyzed transesterification of biologically derived oil to produce biodiesel.
Developments and challenges in biodiesel production from microalgae: A review
(2015-07-14) Shukla, Paritosh; Mehrotra, Sandhya Amol; Mehrotra, Rajesh
The imminent depletion of fossil fuels and the surging global demand for renewable energy have led to the search for nonconventional energy sources. After a few decades of trial and error, the world is now testing the sources of the third generation of fossil fuels, which contain for most parts microalgae. With more than 80% oil content, being adaptable in growth parameters and highly versatile, microalgae are highly promising sources of biofuels in the present time. The present article makes a sweeping attempt to highlight the various methods employed for cultivation of microalgae, techniques to harvest and extract biomass from huge algal cultures, as well as their downstream production and processing procedures. The advantages, limitations, and challenges faced by each of them have been described to some extent. Major concerns pertaining to biofuels are supposed to be their environmental sustainability and economic viability along with their cost effectiveness. This would require a great deal of empirical data on existing systems and a great deal of optimization to generate a more robust one. We have concluded our article with a SWOT analysis of using algae for biodiesel production in a tabulated form.
Evolutionary pattern of four representative DNA repair proteins across six model organisms: an in silico analysis
(INFOFNA, 2014) Chowdhury, Shibasish; Mehrotra, Rajesh
DNA repair refers to a collection of processes by which a cell identifies and corrects damage to DNA molecules that encodes its genome. In this study, we examined evolution of O6-Methylguanine DNA alkyltransferase (MGMT), Xeroderma pigmentosum group D (XPD) protein, G/T mismatch-specific DNA glycosylases, MutS DNA repair proteins of Escherichia coli, Pyrococcus kodakaraensis, Saccharomyces cerevisae, Drosophila melanogester, Mus musculus, and Homo sapiens, which are involved in direct repair, Nucleotide excision repair, base excision repair, and mismatch repair, respectively. Sequence and domain analysis of these proteins indicates that during the course of evolution catalytic residues in the catalytic domain remain conserved. Phylogenetic tree analysis suggested that MGMT proteins of human and mouse have archaeal origin, whereas XPD proteins which are responsible for nucleotide excision repair evolved progressively from lower organism to higher organism. G/T mismatch-specific DNA glycosylases belong to family 1, family 2, and family 4 of uracil-DNA glycosylases superfamily. Family 2 proteins have broader substrate specificity in comparison to proteins of other families. In eukaryotic organisms, prokaryotic MUTS genes are duplicated and various paralogs are present. No unified evolution mechanism can explain the evolution of all these DNA repair proteins. Large sequence variation is observed among same DNA repair proteins of different organisms. However, residues involved DNA repair work and DNA binding remain conserved during the course of evolution.
In Silico Analysis of the Endonuclease III Protein Family Identifies Key Residues and Processes During Evolution
(Springer, 2015-07-07) Chowdhury, Shibasish; Mehrotra, Rajesh
DNA repair refers to a collection of processes by which a cell identifies and corrects damage to genomic DNA molecules. DNA repair processes significantly overcome DNA damage and restore the normal nucleotide sequence and DNA structure. This study focuses on the evolution of the endonuclease III gene/protein family, which plays a key role in the base excision repair pathway. We analyzed 463 homologs of the endonuclease III protein and compared them with the corresponding gene and 16S/18S rRNA sequences to understand the evolutionary processes of this protein family. The sequence analysis and comparison reveal consensus sequence motifs within the ENDO3c and iron–sulfur cluster loop domains that are functionally and structurally important. On the basis of phylogenetic analysis, we propose an evolutionary model of the endonuclease III protein family. Horizontal gene transfer was identified as the key event among bacteria, archaea, and eukaryotic organisms that occurred during the evolution of the endonuclease III gene family among bacteria, archaea, and eukaryotic organisms. This analysis may be exploited to achieve a better prediction of the endonuclease III family gene/protein in unannotated organisms or families of organisms that are completely sequenced as well as in those for which sequencing is ongoing.
Lipase Immobilization Techniques for Biodiesel Production: An Overview
(IBIMA, 2014-05-13) Bhagavatula, Vani; Mehrotra, Rajesh; Mehrotra, Sandhya
The growing energy needs and depleting fuel sources compel us to look towards production of biodiesel, an appropriate alternative. The industrially used chemical catalysis process is beset with problems that enzymatic production using lipases could avoid. In this light, the immobilization of lipases plays an important role in the optimization of the production process. This review discusses the various techniques that have been studied for lipase immobilization, namely adsorption, covalent attachment, entrapment, cross-linked enzyme agglomerates and whole-cell biocatalysts, while highlighting their benefits and drawbacks. It also sheds light on the future of enzyme immobilization and its industrial application.