PRATIKA SINGH - Academia.edu (original) (raw)

Papers by PRATIKA SINGH

Biotechnology for Biofuels: A Sustainable Green Energy Solution, 2020

Biofuels in recent years have turned out as an environment friendly and cost-effective approach t... more Biofuels in recent years have turned out as an environment friendly and cost-effective approach to sustain the rising demand of energy for the growing population. Development of efficient methods for biofuel production using plants and microbes has gained considerable attention. Thus, a different generation of biofuels, i.e. first generation, second generation, third generation, fourth generation, and currently next generation of biofuels has evolved. Each generation overcame the limitations of the earlier generation and differs basically in the substrate being used for the production. For efficient biofuel production researchers and companies have evolved various methods and compositions and acquired respective patents. Also, machineries involved in biofuel production have evolved over time at the laboratory as well as the industrial level. Different countries have formulated various policies and laws to encourage the use of these renewable sources of fuels to overcome the problem of pollution. This chapter encompasses all these aspects related to biofuels with special emphasis on biofuel production utilizing microbes.

Journal of Biomolecular Structure and Dynamics

World Journal of Microbiology and Biotechnology

Siderophores are metal chelating secondary metabolites secreted by almost all organisms. Beside i... more Siderophores are metal chelating secondary metabolites secreted by almost all organisms. Beside iron starvation, the ability to produce siderophores depends upon several other factors. Chemical structure of siderophore is very complex with vast structural diversity, thus the principle challenge involves its detection, quantification, purification and characterisation. Metal chelation is its most fascinating attribute. This metal chelation property is now forming the basis of its application as molecular markers, siderotyping tool for taxonomic clarification, biosensors and bioremediation agents. This has led researchers to develop and continuously modify previous techniques in order to provide accurate and reproducible methods of studying siderophores. Knowledge obtained via computational approaches provides a new horizon in the field of siderophore biosynthetic gene clusters and their interaction with various proteins/peptides. This review illustrates various techniques, bioinformatics tools and databases employed in siderophores' studies, the principle of analytical methods and their recent applications.

Iron is an important micronutrient for plant growth and development. In the case of Oryz... more Iron is an important micronutrient for plant growth and development. In the case of Oryza sativa, iron is made available primarily with the help of iron chelators called phytosiderophores i.e. variants of deoxymugineic acid (DMA). They bind with ferric ions and get internalized through Yellow Stripe Like transporters viz. YSL15 and YSL18. However, due to low amount of secretion of phytosiderophores, rice suffers from iron deficiency. Alternatively, siderophores of plant growth promoting rhizobacteria may support iron uptake and make it available to plants via transporting ferric ions possibly through the same transporters. Present study aims to assess comparative binding of DMA and a xenosiderophore (siderophores used by organisms other than the ones producing them) of rhizobacteria i.e. bacillibactin with Fe3+ ion and subsequent transporters of rice. Protein–protein interaction and gene expression analysis predicts uptake of Fe3+...

Journal of Biomolecular Structure & Dynamics, Feb 9, 2022

Iron is an important micronutrient for plant growth and development. In the case of Oryza sativa,... more Iron is an important micronutrient for plant growth and development. In the case of Oryza sativa, iron is made available primarily with the help of iron chelators called phytosiderophores i.e. variants of deoxymugineic acid (DMA). They bind with ferric ions and get internalized through Yellow Stripe Like transporters viz. YSL15 and YSL18. However, due to low amount of secretion of phytosiderophores, rice suffers from iron deficiency. Alternatively, siderophores of plant growth promoting rhizobacteria may support iron uptake and make it available to plants via transporting ferric ions possibly through the same transporters. Present study aims to assess comparative binding of DMA and a xenosiderophore (siderophores used by organisms other than the ones producing them) of rhizobacteria i.e. bacillibactin with Fe3+ ion and subsequent transporters of rice. Protein-protein interaction and gene expression analysis predicts uptake of Fe3+ by YSL15 from the rhizosphere region and further distribution through YSL18 with the help of various predicted functional partners. Docking studies confirm the thermodynamically more favourable structure of bacillibactin-Fe3+ complex than DMA-Fe3+ complex. Molecular modelling of YSL15 and YSL18 was done through ab initio method and their evaluation by Ramachandran plot, ProSA, ERRAT value and verify 3 D score revealed a good quality models. Comparative binding assessment through docking and molecular dynamics simulation suggests better binding energies of YSL transporters with bacillibactin-Fe3+ complex as compared to DMA-Fe3+ complex. The current study suggests possible application of xenosiderophores of PGPR origin in supporting plant growth via iron uptake and distribution in rice.Communicated by Ramaswamy H. Sarma.

Journal of Biomolecular Structure and Dynamics, 2022

Biochemical, Physiological and Molecular Avenues for Combating Abiotic Stress Tolerance in Plants, 2018

Abstract Abiotic stresses severely affect plant growth and productivity. Therefore, sustaining cr... more Abstract Abiotic stresses severely affect plant growth and productivity. Therefore, sustaining crop yields under adverse environmental stresses is a major challenge of modern agriculture. Polyamines (PA) (putrescine, spermidine, and spermine) play a significant role in this process. These are low-molecular-weight, ubiquitous, aliphatic amine compounds involved in several physiological processes, including cell growth and development, and associated environmental stress tolerances. However, whether increased PAs act as a protector against stress by modulating the reactive oxygen species (ROS) homeostasis, or cause cellular damage generating ROS by their catabolism, is still ambiguous. The major associates in PA-signaling are H 2 O 2 and NO, but PAs can also influence Ca 2 + influx independently of the H 2 O 2 and/or NO-mediated pathways. Comprehensive study of PAs may provide more detailed information on biosynthesis, functional significance, and interactions of PAs with different abiotic stresses through diverse metabolic routes.

Frontiers in Microbiology, 2021

Microorganisms produce various secondary metabolites for growth and survival. During iron stress,... more Microorganisms produce various secondary metabolites for growth and survival. During iron stress, they produce secondary metabolites termed siderophores. In the current investigation, antifungal activity of catecholate siderophore produced by Escherichia coli has been assessed against Aspergillus nidulans. Exogenous application of the bacterial siderophore to fungal cultures resulted in decreased colony size, increased filament length, and changes in hyphal branching pattern. Growth inhibition was accompanied with increased intracellular iron content. Scanning electron microscopy revealed dose-dependent alteration in fungal morphology. Fluorescent staining by propidium iodide revealed cell death in concert with growth inhibition with increasing siderophore concentration. Antioxidative enzyme activity was also compromised with significant increase in catalase activity and decrease in ascorbate peroxidase activity. Siderophore-treated cultures showed increased accumulation of reactive...

Biological Trace Element Research, 2021

Hepatocellular carcinoma is among the leading causes of cancer-related deaths worldwide and needs... more Hepatocellular carcinoma is among the leading causes of cancer-related deaths worldwide and needs efficient and feasible approach of treatment. Present study focuses on exploring the anticancer activity of a secondary metabolite called siderophore of Aspergillus nidulans against hepatocellular carcinoma cell line HepG2. These small peptides are produced by microorganisms including fungi for scavenging iron from its surroundings. Fungi including Aspergillus spp. are known to produce siderophores under iron-limited conditions. Siderophores have high affinity towards iron and are classified into various types. In the present study, siderophore isolated and purified from fungal cultures was confirmed to be of hydroxamate type by chrome azurol sulfonate and Atkin's assay. HPLC analysis confirmed purity while LC-ESI-MS revealed that the siderophore is triacetyl fusigen. Cancerous cells, HepG2, grown under siderophore treatment showed inhibition in growth and proliferation in a dose- and time-dependent manner. Reduction in viability and metabolic activity was evident upon treatment as seen in trypan blue, MTT and WST assay. Fluorescent staining using PI and DAPI confirmed the same while DCFDA staining revealed increased reactive oxygen species production which might have led to cell death and deterioration. Such increase in ROS has been correlated with iron accumulation by assessing intracellular iron level through ICP-MS. To assess the effect of siderophore treatment on normal cells, WRL-68, same assays were carried out but the effect was mostly non-significant up to 48 h. Thus, present work suggests that an optimum dose of siderophore purified from A. nidulans culture might prove a useful anticancer agent.

Arsenic Toxicity: Challenges and Solutions, 2021

International Microbiology, 2019

Siderophores (Gk iron carriers) are low molecular weight secondary metabolites produced by bacter... more Siderophores (Gk iron carriers) are low molecular weight secondary metabolites produced by bacteria, fungi, and plants that have strong binding affinity for iron. Owing to their iron-chelating ability, they are produced mainly when the organism faces iron scarcity. The present study empirically investigated the importance of applying hydroxamate siderophore extracted from Aspergillus nidulans to the cells of Bacillus subtilis for bioremediation of cadmium salt. This investigation deals with siderophore-mediated intracellular Cd accumulation by bacterial cells, growth estimation, biochemical assays like lipid peroxidation, total protein content, carbohydrate content, and iron content estimation. In silico docking and STRING analyses revealed specific interaction between Aspergillus siderophore and receptors present on B. subtilis. Estimation of intracellular Cd by atomic absorption spectroscopy showed more accumulation of Cd ions by B. subtilis in the presence of hydroxamate siderophore. This suggests a possibility of confiscating environmental Cd 2+ by utilizing metal chelation property of siderophores and hence can lead to emerging bioremediation mechanisms for heavy metals. In silico studies support experimental investigation and suggest higher affinity of siderophore for Cd ions as compared with ferric ions.

Acta Physiologiae Plantarum, 2019

Siderophores are secondary metabolites having molecular weight less than 10 KD. They are specific... more Siderophores are secondary metabolites having molecular weight less than 10 KD. They are specifically meant for chelation of ferric ions. They also tend to chelate metals under heavy metal stress, thus reducing their toxic effects. In the current study, experiments have been conducted on wheat plants to analyse siderophore's ability to counteract the adverse impact of arsenic (As) toxicity on physiology of plant seedlings along with biochemical response. As toxicity has been observed to adversely affect the lengths of root and shoot, chlorophyll and carotenoid contents, and activities of various antioxidative enzymes. The present study revealed that the application of hydroxamate-type siderophore isolated from Aspergillus nidulans under toxic condition significantly recovered the growth and helped in amending the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) of wheat genotype (NW1014). At the same time, injury caused by lipid peroxidation was significantly reduced. In silico studies revealed better binding affinity of ferricrocin-arsenate complex leading to thermodynamically stable complex. Encouraging results of As containment by organic biomolecule-siderophore can lead to an emerging bioremediation mechanism brimming with opportunities for agricultural field and environmental clean-up.

Cyanobacteria are an ancient, phylogenetically coherent group of organisms characterized by oxyge... more Cyanobacteria are an ancient, phylogenetically coherent group of organisms characterized by oxygenic photosynthesis. They have evolved several differentiated cell variants that include heterocysts and akinetes to perform specialized functions. Heterocyst pattern formation represents one of the earliest multicellular patterning processes in the history of life. The structure and metabolic activity serve to spatially separate the oxygen-sensitive process of nitrogen fixation from oxygen-producing photosynthesis in vegetative cells. Germination of akinetes of filamentous heterocyst-forming cyanobacteria of the order Nostocales is a crucial process that ensures survival during stress conditions. The current chapter focuses on morphological and structural variation in heterocyst and akinete composition with emphasis on gene regulation for the differentiation process and their metabolism. The ability to form symbiotic associations with different organisms revealing the versatility of hete...

Biofuel from Microbes and Plants

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences

Journal of Trace Elements in Medicine and Biology