Browsing by Author "Shweta Rai"

Now showing 1 - 20 of 22

A novel aldo-keto reductase (AKR17A1) of anabaena sp. PCC 7120 degrades the rice field herbicide butachlor and confers tolerance to abiotic stresses in E. coli
(Public Library of Science, 2015) Chhavi Agrawal; Sonia Sen; Shivam Yadav; Shweta Rai; Lal Chand Rai
Present study deals with the identification of a novel aldo/keto reductase, AKR17A1 from Anabaena sp. PCC7120 and adds on as 17th family of AKR superfamily drawn from a wide variety of organisms. AKR17A1 sharesmany characteristics of a typical AKR such as - (i) conferring tolerance to multiple stresses like heat, UV-B, and cadmium, (ii) excellent activity towards known AKR substrates (isatin and 2-nitrobenzaldehyde), and (iii) obligate dependence on NADPH as a cofactor for enzyme activity. Themost novel attribute of AKR17A1, first reported in this study, is its capability to metabolize butachlor, a persistent rice field herbicide that adversely affects agro-ecosystem and non-target organisms. The AKR17A1 catalyzed- degradation of butachlor resulted into formation of 1,2-benzene dicarboxylic acid and 2,6 bis (1,1, dimethylethyl) 4,-methyl phenol as the major products confirmed by GC-MS analysis. © 2015 Agrawal et al.
All4894 encoding a novel fasciclin (FAS-1 domain) protein of Anabaena sp. PCC7120 revealed the presence of a thermostable β-glucosidase
(Elsevier B.V., 2020) Ruchi Rai; Shilpi Singh; Antra Chatterjee; Krishna Kumar Rai; Shweta Rai; L.C. Rai
In an attempt to mine cyanobacterial genes of potential biotechnological applications, the hypothetical protein All4894 of Anabaena PCC7120, following cloning, heterologous expression, purification and biochemical analysis, revealed the presence of a thermostable β-glucosidase. The glycosylated protein showed apparent molecular mass of ~18.0 kDa, while the purified enzyme depicted activity over wide pH (2.0–9.0) range and 85% stability up to 100 °C. All4894 encoding fascilin-1 domain showed higher specific activity to natural substrate cellobiose (Km = 0.75 mM and Vmax = 0.416 mMmin−1 mg−1) as compared to p-nitrophenyl-β-D-glucopyranoside. Quantitative reverse transcription polymerase chain reaction analysis (qRT-PCR) of all4894 revealed 4.0 to 16.0 fold elevated transcript under salinity, heat, arsenic, cadmium, UV-B and butachlor. The ectopic expression of All4894 in E. coli BL21 (DE3) reaffirmed its stress management capability. In view of the multiple functional attributes i.e. cell adhesion and abiotic stress tolerance All4894 may be regarded as “moonlighting protein” having a novel biomolecule for biotechnological applications including bioethanol production. © 2020 Elsevier B.V.
Alr2321, a multiple stress inducible glyoxalase I of Anabaena sp. PCC7120 detoxifies methylglyoxal and reactive species oxygen
(Elsevier B.V., 2019) Shweta Rai; Ruchi Rai; Prashant Kumar Singh; L.C. Rai
Abiotic stresses enhance the cellular level of reactive oxygen species (ROS) which consequently leads to toxic methylglyoxal (MG) production. Glyoxalases (GlyI & GlyII) catalyze the conversion of toxic MG into non-toxic lactic acid but their properties and functions have been overlooked in cyanobacteria. This is the first attempt to conduct a genome-wide analysis of GlyI protein (PF00903) from Anabaena sp. PCC7120. Out of total nine GlyI domain possessing proteins, only three (Alr2321, Alr4469, All1022) harbour conserve His/Glu/His/Glu metal binding site at their homologous position and are deficient in conserved region specific for Zn2+ dependent members. Their biochemical, structural and functional characterization revealed that only Alr2321 is a homodimeric Ni2+ dependent active GlyI with catalytic efficiency 11.7 × 106 M−1 s−1. It has also been found that Alr2321 is activated by various divalent metal ions and has maximum GlyI activity with Ni2+ followed by Co2+ > Mn2+ > Cu2+ and no activity with Zn2+. Moreover, the expression of alr2321 was found to be maximally up-regulated under heat (19 fold) followed by cadmium, desiccation, arsenic, salinity and UV-B stresses. BL21/pGEX-5X2-alr2321 showed improved growth under various abiotic stresses as compared to BL21/pGEX-5X2 by increased scavenging of intracellular MG and ROS levels. Taken together, these results suggest noteworthy links between intracellular MG and ROS, its detoxification by Alr2321, a member of GlyI family of Anabaena sp. PCC7120, in relation to abiotic stress. © 2019 Elsevier B.V.
Correction to: Ganga river water quality assessment using combined approaches: physico-chemical parameters and cyanobacterial toxicity detection with special reference to microcystins and molecular characterization of microcystin synthetase (mcy) genes carrying cyanobacteria (Environmental Science and Pollution Research, (2022), 29, 9, (13122-13140), 10.1007/s11356-021-16589-1)
(Springer Science and Business Media Deutschland GmbH, 2022) Vigya Kesari; Sanjay Kumar; Indrajeet Yadav; Antra Chatterjee; Shweta Rai; Shraddha Pandey
The last digit of third gene sequence number is needed to be change to 6 instead of 4. Gene bank accession ID numbers are MZ222414, MZ222415, and MZ222416 for mcyE, mcyA, and mcyB genes, respectively. © 2021, Springer-Verlag GmbH Germany, part of Springer Nature.
Cyanobacteria: Role in Agriculture, Environmental Sustainability, Biotechnological Potential and Agroecological Impact
(Springer Singapore, 2017) Shivam Yadav; Shweta Rai; Ruchi Rai; Alka Shankar; Shilpi Singh; L.C. Rai
Cyanobacteria, a group of photosynthetic prokaryotes, have drawn the attention of agricultural scientists due to their notable key features such as the presence of oxygenic photosynthesis along with nitrogen fixation, ease in genetic manipulation and excellent adaptability to various environmental vagaries. Moreover, they have been recognized as an opulent source of various bioactive compounds possessing antibacterial, antiviral, antifungal and anticancer activities. They are also contributing positively in bioremediation and sustainable development of ecosystem. Furthermore, the presence of novel genes opens new ways for generation of transgenic crops with improved productivity and nutritional values. In view of the above, the present chapter is an attempt to cast light on cyanobacterial assistance and their potential role in sustainable development of agriculture and ecosystem. © Springer Nature Singapore Pte Ltd. 2017. All rights are reserved.
Cyanobacterial Biodiversity and Biotechnology: A Promising Approach for Crop Improvement
(Elsevier, 2018) Shivam Yadav; Ruchi Rai; Alok K. Shrivastava; Prashant K. Singh; Sonia Sen; Antra Chatterjee; Shweta Rai; Shilpi Singh; Lal C. Rai
Cyanobacteria due to their remarkable evolutionary advances such as the presence of oxygenic photosynthesis have been considered as an ideal system for plant-based studies in order to assess fundamental biochemical processes like carbon and nitrogen assimilation and photosynthesis processes. Moreover, the exclusive ability of both photosynthesis and nitrogen fixation together with adaptability to various environmental fluctuations of few genera makes them ubiquitous. Cyanobacterial genes involved in carbon metabolism, fatty acid biosynthesis, and pigment biosynthesis have been exploited as substitute for homologous gene sources, targeting enhanced plant productivity and nutritional values. Present chapter sheds light on key contributions of cyanobacterial biodiversity and biotechnology along with the future prospects for developing transgenic crops of high yield and nutritive value utilizing cyanobacterial genes. © 2018 Elsevier B.V. All rights reserved.
Dehydration and rehydration - induced temporal changes in cytosolic and membrane proteome of the nitrogen fixing cyanobacterium Anabaena sp. PCC 7120
(Elsevier B.V., 2017) Sonia Sen; Shweta Rai; Shivam Yadav; Chhavi Agrawal; Ruchi Rai; Antra Chatterjee; L.C. Rai
The effect of drought stress on cytosolic and membrane proteome of nitrogen fixing cyanobacterium, Anabaena PCC 7120 was investigated at different time interval using two-dimensional gel electrophoresis and mass spectrometry. > 300 and 140 protein spots in cytosolic and membrane gels respectively detected by proteomic analysis showed reproducible abundance within replications. Of these proteins, 69 and 86 protein spots in cytosolic and membrane proteome respectively displayed differential expression pattern. The survival strategy adopted by Anabaena PCC 7120 under dehydration as presumed by proteomic analysis can be summarized as 1) increased abundance of proteins: Mn catalase, OR, AhpC, SodA, SodB, GST and All1124 to mitigate oxidative damage, 2) minimization of energy expenditure by inhibition of photosynthesis through down-regulation of photosynthetic apparatus, antenna proteins, PSI, PSII and cytochrome b6f and respiration, 3) increased abundance of membrane porins (Omp85, OprB-I, All7614 and Alr4550) and TolC conceivably to support carbohydrate transport for enduring stress and recovery, 4) increase in phosphate transporter (PstS1) to improve phosphate assimilation required to recover cellular damage during rehydration and 5) increased abundance of K+ ATPase during prolonged dehydration and minor abundance of Na+/H+ ATPase during early rehydration to maintain cellular ion homeostasis. Dehydration, however, strongly impaired cytosolic proteins associated with nitrogen fixation, energy metabolism, amino acid and nucleic acid biosynthesis which were resumed after prolonged rewetting. Severely decreased abundance of novel proteins Alr1819, Alr2903, Alr3514, Alr2751 and All3324 serve as the marker for dehydration stress. The above results help in investigating the involvement of the proteins in protection and adaptation mechanisms associated with rejuvenation of the active state of Anabaena sp. PCC 7120. © 2017
Demineralization of Coal from Johilla Coalfield using Neutrophilic Native Bacteria: A Novel Technique to obtain REE from Coal
(Geological Society of India, 2024) Shweta Rai; Asha Lata Singh; Prakash K. Singh
Mineral matter in coal is the host of several environmentally sensitive elements and a potential source of Rare Earth Elements (REE). During combustion, some trace elements are liberated as gas, while others get concentrated in ash, contaminating soil and local water bodies. Minimizing the inorganic content makes the coal clean and eventually increases its calorific value. Bacteria serve as an eco-friendly remediation tool, particularly neutrophilic ones that facilitate the treatment at mild pH and ambient temperatures. Use of native bacteria accelerates the treatment process by readily adapting to substrates. We present the remediation potential of three native neutrophilic bacteria in this study. After six days of treatment, Bacillus sp. CpH06 has reduced ash yield by 15.96%, trace elements by 26% to 75%, and REE by 24% to 50%. Bacillus anthracis CpH08 has reduced ash yield by 22.6%, trace elements by 6.4% to 70.5%, and REE by 8.4% to 37%. Maximum ash yield reduction of 22.91% was attained by the Cronobacter sp. CpH10 including reduction of 8.1% to 73% of trace elements and 26% to 48% of REEs. The FTIR spectra reveal alterations in both peak intensity and position of inorganic functional groups resulting from the removal of elements, formation of new bonds, and the elimination of certain pre-existing functional groups. XRD spectra indicate bio-oxidation mechanism, exhibited by the removal of copper sulfate hydroxide and pyrite along with formation of Jarosite and metal-sulfide peaks. The findings encourage further research on the effectiveness and performance of these bacteria on diverse types of coals. © 2024 Geological Society of India, Bengaluru, India.
Exploring the membrane proteome of the diazotropic cyanobacterium Anabaena PCC7120 through gel-based proteomics and in silico approaches
(Elsevier, 2015) Sonia Sen; Chhavi Agrawal; Yogesh Mishra; Shweta Rai; Antra Chatterjee; Shivam Yadav; Shilpi Singh; L.C. Rai
This paper focuses on the gel-based membrane proteomics from diazotrophic cyanobacterium Anabaena PCC7120 by modifying the protocol of Hall et al. [1]. The bioinformatic analysis revealed that 59 (29 integral, 30 peripheral) of the 67 proteins identified were membrane proteins. Of the 29 integral proteins, except Alr0834, the remaining 28 contained 1-12 transmembrane helices. Sixteen integral proteins harboring signal peptides (Sec/TAT/LipoP) suggest that protein targeting in Anabaena involves both sec-dependent and sec-independent pathways. While majority of photosynthesis and respiration proteins (21 of 24) were confined to broad pH gradient the hypothetical and unknown (12 of 13), and cell envelope proteins (3 of 3) preferred the narrow pH range. Of the 5 transporters and binding proteins, Na+/H+-exchanging protein and Alr2372 were present in broad, pstS1 and cmpD in narrow and cmpA was common to both pH ranges. The distribution of proteins across pH gradient, thus clearly indicates the functional and structural diversity in membrane proteome of Anabaena. It requires mention that protochlorophyllide oxido-reductase, Na+/H+-exchanging protein, All1355, Alr2055, Alr3514, Alr2903 and Alr2751 were new entries to the 2DE membrane protein profile of Anabaena. This study demonstrates suitability of the modified protocol for the study of membrane protein from filamentous cyanobacteria. Significance: Anabaena sp. PCC7120 is used as a model organism due to its agriculture significance as biofertilizer, close resemblance with higher plant chloroplast and availability of full genome sequence. Although cytosolic proteome has been explored a lot membrane proteins are still understudied as they are notoriously difficult to display using 2-D technology. Identification and characterization of these proteins is therefore required to elucidate and understand cellular mechanisms. The purpose of this study was to develop a protocol suitable for membrane protein extraction from Anabaena. Additionally, by homology comparison or domain assignment a possible function could be ascribed to novel uncharacterized proteins which will serve as a useful reference for further detailed studies of membrane system in filamentous cyanobacteria. Resolution of membrane proteins ranging from least (single transmembrane helix) to highly hydrophobic (several transmembrane helices) one on 2D gels recommends the gel based approach for identification of membrane proteomics from filamentous cyanobacteria. This article is part of a Special Issue entitled: Proteomics in India. © 2015 Elsevier B.V.
Functional characterization of alr0765, a hypothetical protein from anabaena PCC 7120 involved in cellular energy status sensing, iron acquisition and abiotic stress management in E. Coli using molecular, biochemical and computational approaches
(Bentham Science Publishers, 2020) Antra Chatterjee; Shilpi Singh; Ruchi Rai; Shweta Rai; L.C. Rai
Background: Cyanobacteria are excellent model to understand the basic metabolic processes taking place in response to abiotic stress. The present study involves the characterization of a hypothetical protein Alr0765 of Anabaena PCC7120 comprising the CBS-CP12 domain and deciphering its role in abiotic stress tolerance. Methods: Molecular cloning, heterologous expression and protein purification using affinity chromatography were performed to obtain native purified protein Alr0765. The energy sensing property of Alr0765 was inferred from its binding affinity with different ligand molecules as analyzed by FTIR and TNP-ATP binding assay. AAS and real time-PCR were applied to evaluate the iron acquisition property and cyclic voltammetry was employed to check the redox sensitivity of the target protein. Transcript levels under different abiotic stresses, as well as spot assay, CFU count, ROS level and cellular H2O2 level, were used to show the potential role of Alr0765 in abiotic stress tolerance. In-silico analysis of Alr0765 included molecular function probability analysis, multiple sequence analysis, protein domain and motif finding, secondary structure analysis, protein-ligand interaction, homologous modeling, model refinement and verification and molecular docking was performed with COFACTOR, PROMALS-3D, InterProScan, MEME, TheaDomEx, COACH, Swiss modeller, Modrefiner, PROCHECK, ERRAT, MolProbity, ProSA, TM-align, and Discovery studio, respectively. Results: Transcript levels of alr0765 significantly increased by 20, 13, 15, 14.8, 12, 7, 6 and 2.5 fold when Anabaena PCC7120 treated with LC50 dose of heat, arsenic, cadmium, butachlor, salt, mannitol (drought), UV-B, and methyl viologen respectively, with respect to control (untreated). Heterologous expression resulted in 23KDa protein observed on the SDS-PAGE. Immunoblotting and MALDI-TOF-MS/MS, followed by MAS-COT search analysis, confirmed the identity of the protein and ESI/MS revealed that the purified protein was a dimer. Binding possibility of Alr0765 with ATP was observed with an almost 6-fold increment in relative fluorescence during TNP-ATP binding assay with a λ max of 538 nm. FTIR spectra revealed modification in protein confirmation upon binding of Alr0765 with ATP, ADP, AMP and NADH. A 10-fold higher accumulation of iron was observed in digests of E. coli with recombinant vector after induction as compared to control, which affirms the iron acquisition property of the protein. Moreover, the generation of the redox potential of 146 mV by Alr0765 suggested its probable role in maintaining the redox status of the cell under environmental constraints. As per CFU count recombinant, E. coli BL21 cells showed about 14.7, 7.3, 6.9, 1.9, 3 and 4.9 fold higher number of colonies under heat, cadmium (CdCl2), arsenic (Na3AsO4), salt (NaCl), UV-B and drought (mannitol) respectively compared to pET21a harboring E. coli BL21 cells. Deterioration in the cellular ROS level and total cellular H2O2 concentration validated the stress tolerance ability of Alr0765. In-silico analysis unraveled novel findings and attested experimental findings in determining the role of Alr0765. Conclusion: Alr0765 is a novel CBS-CP12 domain protein that maintains cellular energy level and iron homeostasis which provides tolerance against multiple abiotic stresses. © 2020 Bentham Science Publishers.
Ganga river water quality assessment using combined approaches: physico-chemical parameters and cyanobacterial toxicity detection with special reference to microcystins and molecular characterization of microcystin synthetase (mcy) genes carrying cyanobacteria
(Springer Science and Business Media Deutschland GmbH, 2022) Vigya Kesari; Sanjay Kumar; Indrajeet Yadav; Antra Chatterjee; Shweta Rai; Shraddha Pandey
Water quality assessment relies mostly on physico-chemical-based characterization; however, eutrophication and climate change advocate the abundance of toxic microcystins (MCs) producing cyanobacteria as emerging bio-indicator. In the present study, a spatial-temporal analysis was carried out at ten sampling sites of Prayagraj and Varanasi during June 2017 and March 2018 to determine the Ganga River water quality using physico-chemical parameters, cyanobacteria diversity, detection of MCs producing strains and MC-LR equivalence. Coliform bacteria, COD, NO3-N, and phosphate are the significant contaminated parameters favoring the growth of putative MCs producing cyanobacteria. National Sanitation Foundation WQI (NSFWQI) indicates water quality, either bad or medium category at sampling points. The morphological analysis confirms the occurrence of diverse cyanobacterial genera such as Microcystis, Anabaena, Oscillatoria, and Phormidium. PCR amplification affirmed the presence of toxic microcystin (mcy) genes in uncultured cyanobacteria at all the sampling sites. The concentration of MC-LR equivalence in water samples by protein phosphatase 1 inhibition assay (PPIA) and high-performance liquid chromatography (HPLC) methods was observed in the range of 23.4–172 ng/L and 13.2–97.5 ng/L respectively which is lower than the harmful exposure limit by World Health Organization (WHO). Ganga isolate 1 was identified as Microcystis based on partial 16S rDNA sequence and its toxicity was confirmed due to presence of mcy genes and MCs production potential. These findings suggest the presence of MCs producers as new emerging parameter to monitor water quality index and identification up to species level will be valuable for restoration strategies of river Ganga. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Geochemical and petrological characteristics coupled with stable isotope of the Permian Gondwana coals from Tatapani–Ramkola Coalfield, Son–Mahanadi Basin, India: Insights for paleodepositional and paleoclimate conditions
(Elsevier B.V., 2025) Neeraj K. Upadhayay; Amiya Shankar Naik; Shweta Rai; Prakash Kumar Singh; Alok Kumar; Afikah Binti Rahim; Mohammed Hail Hakimi; Govind Kumar; Pramod Kumar Rajak
This study aimed to investigate the quality and rank of the Tatapani-Ramkola coal and decipher the paleoclimate and depositional conditions during coal formation, explicitly focusing on vegetation sources, detrital contributions, and paleomire conditions. The studied coals exhibit a moisture between 4.0 % and 12.8 % and a volatile matter yield in the range of 28.8–49.5 wt% (dry ash–free basis), classifying them as subbituminous–A to bituminous in rank. This finding is supported by the vitrinite reflectance (VRo) values between 0.5 and 0.7 %. Maceral compositions reveal the dominance of vitrinite (average 47.8–62.4 %) followed by inertinite (average 13.0–29.9 %) and liptinite (average 8.5–13.1 %). This finding of the maceral characteristics together with the mineral composition (primarily clay, carbonate, and sulfide), show that the Tatapani–Ramkola coals were formed under mildly oxic–to–anoxic conditions in limno–telmatic to telmatic paleomires and contributions from forest and herbaceous vegetation. Geochemical isotope indicators, such as δ13C (−24.149 ± 0.825 ‰) and δ15N (+2.710 ± 0.344 ‰), suggest that the coals formed from C3 land plants under warm and humid climate conditions. Major oxide ratios indicate a moderate to high degree of chemical weathering in the source area, further confirming the prevailing warm and humid climate during the peat accumulation. The detrital/authigenic index (DAI) suggests significant detrital influence and authigenic sediment formation in the Tatapani–Ramkola coals. This study provides critical insights into the depositional history and paleoclimate of the Tatapani–Ramkola Basin, contributing to a deeper understanding of Permian coal formation processes. © 2025 Elsevier B.V.
Identification and functional characterization of four novel aldo/keto reductases in Anabaena sp. PCC 7120 by integrating wet lab with in silico approaches
(Springer Verlag, 2017) Chhavi Agrawal; Shivam Yadav; Shweta Rai; Antra Chatterjee; Sonia Sen; Ruchi Rai; L.C. Rai
Aldo/keto reductases (AKRs) constitute a multitasking protein family that catalyzes diverse metabolic transformations including detoxification of stress generated reactive aldehydes. Yet this important protein family is poorly understood particularly in cyanobacteria, the ecologically most diverse and significant group of micro-organisms. Present study is an attempt to characterize all putative AKRs of Anabaena sp. PCC 7120. In silico analysis, it revealed the presence of at least four putative AKRs in Anabaena PCC7120 genome. All four proteins share less than 40% sequence identity with each other and also with the identified members of AKR superfamily and hence deserve to be assigned in new families. Dissimilarity in sequences is also reflected through their substrate specificity. While reduction of trans-2-nonenal, a LPO-derived reactive aldehyde was common across the four proteins, these proteins were found to be activated during heat, salt, Cd, As, and butachlor treatments, and their ectopic expression in Escherichia coli conferred tolerance to the above abiotic stresses. These findings affirm the role of AKRs in providing a broad tolerance to environmental stresses conceivably by detoxifying the stress-generated reactive aldehydes. © 2017, Springer-Verlag Berlin Heidelberg.
Molecular and biochemical characterization of All0580 as a methylglyoxal detoxifying glyoxalase II of Anabaena sp. PCC7120 that confers abiotic stress tolerance in E. coli
(Elsevier B.V., 2019) Shweta Rai; Shivam Yadav; Ruchi Rai; Antra Chatterjee; Shilpi Singh; L.C. Rai
Abiotic stresses enhance cellular reactive oxygen species (ROS) level which results in toxic methylglyoxal (MG) production. Glyoxalases catalyze the conversion of toxic MG into non-toxic lactic acid whose properties and function are still unknown in cyanobacteria. This is the first attempt to characterize All0580 from Anabaena sp. PCC7120 as GlyII using in silico and wet lab approaches. Data of functional complementation of E. coli GlyII mutant (ΔgloB), enzyme kinetics and ESI-MS analysis suggested that All0580 harbors distinctive GlyII activity. The catalytic efficiency of All0580 (3 × 106 M−1 s−1) is higher than Arabidopsis GlyII. AAS analysis revealed the presence of a binuclear Zn/Fe centre in All0580 active site. The qRT-PCR of the target gene revealed maximum up-regulation in salinity followed by drought, arsenic, heat, and UV-B stresses. BL21/pET-21a-all0580 showed 1.5 to 10 fold increased growth and up to 4 fold decreased intracellular MG level as compared to BL21/pET-21a cells under various abiotic stresses and MG. A 39% drop in ROS generation by BL21/pET-21a-all0580 under MG stress suggested its potential to manage MG toxicity. Above attributes suggest that the hypothetical protein All0580 is a novel GlyII of cyanobacteria which heterologously confers tolerance to multiple abiotic stresses in E. coli. © 2018 Elsevier B.V.
Molecular characterization of two novel proteins All1122 and Alr0750 of Anabaena PCC 7120 conferring tolerance to multiple abiotic stresses in Escherichia coli
(Elsevier B.V., 2019) Sonia Sen; Ruchi Rai; Antra Chatterjee; Shweta Rai; Shivam Yadav; Chhavi Agrawal; L.C. Rai
In- silico and functional genomics approaches have been used to determine cellular functions of two hypothetical proteins All1122 and Alr0750 of Anabaena sp. PCC 7120. Motif analysis and multiple sequence alignment predicted them as typical α/β ATP binding universal stress family protein-A (UspA) with G-(2×)-G-(9×)-G(S/T) as conserved motif. qRT-PCR data under UV-B, NaCl, heat, As, CdCl2 mannitol and methyl viologen registered approximately 1.4 to 4.3 fold induction of all1122 and alr0750 thus confirming their multiple abiotic stress tolerance potential. The recombinant E. coli (BL21) cells harboring All1122 and Alr0750 showed 12–41% and 23–41% better growth respectively over wild type control under said abiotic stresses thus revalidating their stress coping ability. Functional complementation on heterologous expression in UspA mutant E. coli strain LN29MG1655 (ΔuspA::Kan) attested their UspA family membership. This study tempted us to suggest that recombinant Anabaena PCC 7120 over expressing all1122 and alr0750 might contribute to the nitrogen economy in paddy fields experiencing array of abiotic stresses including drought and nutrient limitation. © 2018 Elsevier B.V.
Optimization of extrinsic parameters for beneficiation of coal with the help of Cronobacter sp
(Taylor and Francis Ltd., 2024) Shweta Rai; Asha Lata Singh; Prakash K Singh; Sunil Kumar; Donald Huisingh
Beneficiation increases the calorific value of low-grade coal and extracts environmentally sensitive elements. Bacteria may be used as eco-friendly coal cleaning tool, but the treatment is influenced by several extrinsic and intrinsic factors. This study examined five extrinsic factors, namely particle size of coal, pulp density, bacterial biomass concentration, number of bacterial beads (immobilized bacterial cells) and the duration of treatment. For optimization, the test runs were designed using Taguchi L16 orthogonal array, determining optimal values through S/N ratio analysis and individual parameter contribution using ANOVA. The optimal conditions obtained for sub-bituminous coal beneficiation using Cronobacter sp. are 80–120 mesh particle size, 30% pulp density, 750 mg bacterial biomass/g coal, 25 bacterial beads, and six days of treatment resulting in 13.36% ash yield reduction. Particle size had the highest impact (69.4%), followed by treatment duration (13.1%), pulp density (6.3%), bacterial biomass (6.3%), and bacterial bead number (4.8%). A regression model attributed only 42% influence of these extrinsic factors on inorganic removal from coal. Therefore, further research on other factors, particularly intrinsic ones, in inorganic matter liberation is imperative. These findings can be used for designing experiments that optimize the extraction of cleaner fuel from various types of low-grade coal. © 2023 Taylor & Francis Group, LLC.
Organic Petrological Facets and the Evolution of Paleomire, Matasukh Lignite Deposits, Rajasthan, India
(Springer, 2023) A.S. Naik; Vishvajeet Singh; D. Mohanty; R.K. Majhi; Govind Kumar; N. Upadhyay; Manju Kumari; Shweta Rai
The present research work attempts to understand the organo-petrological facets of the lignite hosted in the Tertiary successions in Rajasthan. The maceral diversity was analyzed qualitatively and quantitatively which recorded huminite as the dominant microscopic constituent followed by inertinite and liptinite. The rank parameter of coal evaluated through vitrinite reflectance measurement random (VRo) shows the values vary between 0.19 to 0.27% suggesting lignite in rank. The petrographic investigation point towards the primary phase of degradation of organic matter corroborated through the dominance of huminite suggesting frequent flooding and the presence of funginite, demonstrating intense fungal activity in the mire. The paleodepositional model records elevated values of gelification Index (GI) ranging from 1.63 to 3.88 with well-preserved cell structures pointing towards an early phase of coalification. The model and plot of GI and TPI show that the paleomire developed in a limnic setting. © 2023, Geological Society of India.
Signal perception and mechanism of salt toxicity/tolerance in photosynthetic organisms: Cyanobacteria to plants
(Springer International Publishing, 2015) Chhavi Agrawal; Sonia Sen; Antra Chatterjee; Shweta Rai; Shivam Yadav; Shilpi Singh; L.C. Rai
High salt concentration represents one of the most significant abiotic constraints, affecting all life forms including plants and cyanobacteria. Soil salinity curtails plant growth by way of osmotic, ionic and oxidative stresses resulting in multiple inhibitory effects on various physiological processes such as growth, photosynthesis, respiration and cellular metabolism. In order to combat high salinity, various adaptive strategies employed include ion homeostasis achieved by ion transport and compartmentalization of injurious ions, osmotic homeostasis by accumulation of compatible solutes/osmolytes and upregulation of antioxidant defence mechanism. The aforesaid processes are executed through SOS and MAPK signalling pathways leading to modulation of gene expression. Salt stress signal transduction pathways initiate through sensing extracellular Na+ ions causing modification of constitutively expressed transcription factors. This modification is responsible for expression of early transcriptional activators such as CBF/DREB gene family which eventually activate stress tolerance effector genes such as osmolyte biosynthesis genes, detoxification enzymes, and chaperones. Various genes/cDNAs encoding proteins involved in these adaptive mechanisms have been isolated and identified. Bioinformatic predictions through docking revealed interaction of salt across the species at conserved domains and motifs as a possible mechanism for response of a particular protein under salt stress. In this chapter, major aspects of salt stress are reviewed with emphasis on its detrimental consequences and biochemical and molecular mechanisms of signal transduction in plants and cyanobacteria under high salinity. © Springer International Publishing Switzerland 2015.
Study of Hydrocarbon Source Potential of Kapurdi Lignites of Barmer Basin, Rajasthan, Western India
(Springer, 2021) P.K. Rajak; V.K. Singh; Aniruddha Kumar; Vishvajeet Singh; Ankita Rai; Shweta Rai; K.N. Singh; Mamta Sharma; A.S. Naik; Neeraj Mathur; Prakash K. Singh
The present investigation is an attempt to study hydrocarbon source potential of early Paleogene lignites of Kapurdi, Barmer Basin. The samples collected from the working mines have been subjected to petrographic and geochemical analyses. The petrographic study includes both maceral as well as microlithotype analyses whereas geochemical study includes proximate and ultimate analyses. Besides, rock eval pyrolysis, FTIR and NMR studies have also been carried out. The analytically generated data were also correlated and checked with empirical equations. The study shows that these lignites of Barmer Basin are rich in kerogen type-III organic matter and contain high concentration of reactive macerals (huminite + liptinite) to the tune of ∼98% (mineral matter free basis) and they have attained low maturity (Rmax is 0.43%). These lignites have a fairly high conversion factor (95–97%) and oil yield (65–67%) which is also supported by the rock-eval data. Further, 1H and C13 shifts of NMR also suggest a high potential of hydrocarbon of Kapurdi lignites. © 2021, GEOL. SOC. INDIA.
Study of Micro-structures and their Relation with Occurrence of Mineral Matter in Ramagundam Coals, Godavari Basin, India: Implications on Coal and Hydrocarbon Industries
(Springer, 2022) Shweta Rai; Ankita Rai; Kajal Kumar; Amiya S. Naik; Neelratan Singh; D.K. Srivastava; Prakash K. Singh
This paper is an attempt to study the relationship between coal microstructures and mineral matter in Ramagundam Gondwana coal of Godavari basin. For this purpose, the occurrence and distribution of mineral matter in different lithotypes and microlithotypes have been investigated and their association with organic matter has been studied. The work has been accomplished through detailed petrography, SEM-EDS and XRD studies. Presence of clay minerals and pyrite, along with trace amounts of apatite, ankerite, hematite, calcite, dolomite and quartz has been revealed from the study. The lithotypes and bands have variable concentrations of mineral matter which occurs associated with different microstructures in coal. Optical microscopy reveals that mineral matter occurs maximum in dull-coal but it is almost equally distributed in dull-banded coal and banded-bright coal. The study also incorporates the nature of fracture and phyteral pores and their association with mineral matter. Vitrain is characterized by cleats, micropores and microfractures which are often filled up partially or completely with mineral matter; fusain has well preserved tracheids with open pits and partially homogenized cell structure filled with mineral matter. In durain and clarain lithotypes, the minerals are intimately intergrown with the organic constituents. © 2022, Geological Society of India, Bengaluru, India.