Browsing by Author "Savita Singh"

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Alleviation of NaCl toxicity in the cyanobacterium Synechococcus sp. PCC 7942 by exogenous calcium supplementation
(Springer Netherlands, 2018) Ekta Verma; Sindhunath Chakraborty; Balkrishna Tiwari; Savita Singh; Arun K. Mishra
Salinity (NaCl) is one of the major problems associated with irrigated agricultural lands, especially rice fields. Being the common inhabitants of rice fields, cyanobacteria frequently experience high concentration of NaCl which in turn causes cellular damage. Therefore, mitigation of NaCl stress in cyanobacteria, plant growth-promoting microorganisms, is of utmost importance. The present study was designed to investigate the role of calcium in the alleviation of NaCl stress-induced cellular in Synechococcus sp. PCC 7942. The cyanobacterium was subjected to sub-lethal concentration of NaCl (800 mM) with and without the supplementation of calcium (1 mM CaCl2) for 8 days. The results showed a drastic reduction in growth due to excess NaCl, but supplementation of CaCl2 reduced the salt stress damage and partially restored growth. Application of calcium increased pigment contents, photosynthetic efficiency, antioxidative enzyme activity, osmolyte contents and reduced the intracellular sodium ion concentration, MDA content, electrolyte leakage and free oxygen radical generation. Furthermore, proteins involved in photosynthesis, respiration, ATP synthesis and protein synthesis along with two hypothetical proteins were also observed to be upregulated in the cyanobacterium in presence of calcium. Furthermore, proteins related to oxidative stress defence, nitrogen metabolism, carbohydrate metabolism, fatty acid metabolism and secondary metabolism were found to be upregulated by several fold. Therefore, our study suggests that calcium suppresses salt toxicity in Synechococcus sp. PCC 7942 by restricting the entry of Na+ into the cell, increasing osmolyte production and upregulating defence-related proteins. © 2018, Springer Science+Business Media B.V., part of Springer Nature.
Bioremediation of pesticides residues: A psychological approach
(Nova Science Publishers, Inc., 2018) Savita Singh; Ashutosh Kumar; S. P. Jeevan Kumar; Mohd Imran; Madan Kumar; Arvind Nath Singh; Manoj Kumar Tripathi
To increase the food production, pesticides have been used excessively; as a result, they have become a threat to the environment. In the present era, microbial degradation is one of the important techniques for degradation of pesticides from agricultural lands. Studies have been conducted on the use of different microbes such as bacteria, fungi and genetically modified microorganisms for degradation of pesticides. Case studies and researches have revealed that microbial consortia of naturally occurring microbes isolated from particular contaminated environments have potential to degrade pesticides at faster rate rather than individual microbes. Microalgae and cyanobacteria exhibiting high growth rate and biodegradation potential are yet to be explored. Microalgae and cyanobacteria are cosmopolitan in nature ranging from unicellular to filamentous forms that inhabit several environmental conditions. In order to re-evaluate the current scenario of pesticide contamination and the role of micro algae and cyanobacteria have been discussed. The chapter highlights the use of microalgae and cyanobacteria in bioremediation of pesticide contamination and remedies using psychological approaches. © 2018 by Nova Science Publishers, Inc. All rights reserved.
Exopolysaccharide production in Anabaena sp. PCC 7120 under different CaCl2 regimes
(Springer India, 2016) Savita Singh; Ekta Verma; Niveshika; Balkrishna Tiwari; Arun Kumar Mishra
Influence of various levels of CaCl2 (0, 1, 10 and 100 mM) on exopolysaccharide production has been investigated in the cyanobacterium Anabaena 7120. At the concentration of 1 mM CaCl2, growth was found to be stimulatory while 100 mM was sub lethal for the cyanobacterial cells. Estimation of EPS content revealed that EPS production depends on the concentration of calcium ions in the immediate environment with maximum being at10 mM CaCl2. A possible involvement of alr2882 gene in the process of EPS production was also revealed through qRT-PCR. Further, FTIR-spectra marked the presence of aliphatic alkyl-group, primary amine-group, and polysaccharides along with shift in major absorption peaks suggesting that calcium levels in the external environment regulate the composition of EPS produced by Anabaena 7120. Thus, both quantity and composition of EPS is affected under different calcium chloride concentrations presenting possibilities of EPS with novel unexplored features that may offer biotechnological applications. © 2016, Prof. H.S. Srivastava Foundation for Science and Society.
Green single-step hydrothermal synthesis of fluorescent carbon dots from Lantana camara flower for the effective fluorescent detection of Cr(VI) and live cell imaging
(Springer Science and Business Media Deutschland GmbH, 2024) Vikky Kumar Mahto; Vikas Kumar Singh; Vipendra Kumar Singh; Avinash Singh; Savita Singh; Arjun Kumar Mehara; Naina Rajak; Anurag Mishra; Neha Garg; Akanksha Upadhyay; Abhishek Rai; Ankit Kumar Singh
Chromium is one of the heavy metal ions showing high toxicity and mutagenicity. Owing to this, selective sensing of Cr(VI) from sample metrics is a challenging and tedious process. In the present work, we have synthesized fluorescent carbon dots (FCDs) using the flower of Lantana camara through a one-step hydrothermal method. Various spectroscopic techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), EDAX, and Raman analysis well supported the successful synthesis of FCDs. The obtained FCDs revealed a bright blue color under UV-light exposure (@ 365 nm), with excellent optical properties and a fluorescence quantum yield of 29%. Furthermore, FCDs showed excellent fluorescence stability, high ionic strength, good water solubility, low cytotoxicity, and well biocompatibility. Therefore, the proposed FCDs were employed for selective turn-off sensing of toxic Cr(VI) in an aqueous medium with a limit of detection (LOD) of 0.10 µM. Interestingly, the low cytotoxicity and excellent biocompatibility enable the FCDs as a good candidate for cell imaging agents as well as intracellular turn-off sensing of Cr(VI) in HEK-293 cells. Thus, the present work significantly converts biomass of weed plants into a fluorescent probe in a simple and cost-effective way for the detection of Cr(VI) in water samples as well as in living cells. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
IAA induced biomass and lipid overproduction in microalga via two-stage cultivation strategy: Characterization using FTIR/CHNS/TGA/DTG and 1H- NMR for bioenergy potential
(Elsevier Ltd, 2024) Savita Singh; Avinash Singh; Sakshi Singh; Nitesh Prasad; Laxmi; Prabhakar Singh; Ravi Kumar Asthana
Microalgae are an excellent carbon concentrators with substantial lipid content. However, biomass production vis-à-vis lipid hyperaccumulation is a major constraint in the biofuel economy. In this regard, Dunaliella salina, an oleaginous, wall less microalga, was grown in graded concentration of indole-3-acetic acid (IAA). There was a significant increase in biomass (1.57-fold), photosynthetic efficiency (Fv/Fm = 0.72), and chlorophyll a content in 0.25 mg/L IAA supplemented cultures over the control (stage I). However, supplementation of IAA under nitrogen deprivation (stage II) led to a significant rise in the lipid content (47 % DCW), carbohydrate (18.37 %) and simultaneous reduction in the oxidative status (MDA, H2O2, O2·−, OH·) over the control. Further, 0.25 mg/L IAA supplemented cultures under nitrogen starvation were undertaken for biomass and lipid characterization. Nile red based flow cytometric analysis revealed an apparent increase in the neutral lipid fluorescence, also validated by 1H- NMR based lipidome, revealing the presence of triacylglycerol (TAG, 4.12–4.31 ppm). FTIR spectra revealed the increased absorbance at 2926 cm−1, 1740 cm−1 and 1025 cm−1, validating the increased carbohydrate and lipid, while biomass pyrolysis showed 81.42 % decomposition in the active pyrolytic zone as recorded by the TGA/DTG analysis. Interestingly, elemental analysis (CHNS) of the biomass showed an increased carbon and hydrogen %, HHV (19.94 MJ kg−1), H/C ratio (1.78), and CO2 fixation rate. Thus, the present study opens new avenues for the economic feasibility of bioenergy/biofuel production from microalgal biomass at commercial scale. © 2024 Elsevier Ltd
In silico molecular docking analysis of cancer biomarkers with GC/MS identified compounds of Scytonema sp.
(Springer, 2020) Niveshika; Savita Singh; Ekta Verma; Arun Kumar Mishra
This study was aimed to perform pre-clinical evaluation of the gas chromatography–mass spectrometry (GC/MS) identified bioactive compounds of cyanobacterium Scytonema sp. MGL002 as an anticancer drug resource using in silico docking approaches. Among the twenty GC/MS identified cyanobacterial compounds, only four of them viz. tetradecanoic acid; palmitoleic acid; 9,12-octadeca dien-1-ol, (Z, Z)- and 6-octadecanoic acid (Z)- were found to be potent anticancer therapeutic agent through molecular docking study. These anticancerous compounds were also accepted as a potent drug-like compound through Lipinski drug likeliness test and ADME (Absorption, distribution, metabolism, excretion and toxicity) toxicity investigation. Studies on molecular docking of ligand {tetradecanoic acid, palmitoleic acid and 9,12-octadeca dien-1-ol, (Z, Z)-} with cancer targets revealed that these compounds interacted more efficiently with hsp90 protein (PDBID:3NMQ) with good binding affinity and best positive energy. Ligand–protein interaction was strengthened by electrostatic, van der Waals, covalent and hydrogen bonds. There might be possibility that these cyanocompounds bind with hsp90, modify their orientation and ultimately alter the functioning of hsp90 protein. In this respect, the present report provides useful insights to widen the knowledge on molecular interaction for new anticancer compound and opens new research area to work further on cancer cell lines followed by clinical trials to validate anticancerous property of these cyanocompounds. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature.
Inactivation of ntcA gene revealed differential proteome expression and induction of some hypothetical proteins in the cyanobacterium Anabaena sp. PCC 7120 and its derivative ntcA mutant under different levels of calcium
(Taylor and Francis Ltd., 2019) Savita Singh; Ekta Verma; Arun Kumar Mishra
Calcium is an important macronutrient for both prokaryotes and eukaryotes. It acts as an important second messenger mediating rapid response to environmental conditions. The present investigation deals with proteome profiling of Anabaena 7120 and its derivative ntcA mutant in response to varied calcium doses (0, 1 and 10 mM CaCl2). Concentration of 1 mM CaCl2 salt was the optimum concentration whereas 10 mM CaCl2 was the inhibitory concentration for both the wild type and mutant strains. The results showed highly significant alteration in terms of protein abundance and differential response related to key processes of photosynthesis, energy and metabolism, nitrogen metabolism, oxidative and antioxidative defence, transport and signalling and fatty acid metabolism. In the wild type proteins related to photosynthesis and nitrogen metabolism showed upregulation at 1 mM CaCl2 concentration while antioxidative defence related proteins were down-regulated. In the mutant however, proteins related to photosynthesis and nitrogen metabolism exhibited severe down-regulation. Some hypothetical proteins were also realized during proteome analysis. Overall, our results suggested that NtcA have a potential role in regulation of calcium ion dependent key processes underlying in various metabolic activities of the cyanobacterium Anabaena 7120. © 2018, © 2018 Societá Botanica Italiana.
Isolation, characterization and molecular phylogeny of multiple metal tolerant and antibiotics resistant bacterial isolates from river Ganga, Varanasi, India
(Taylor and Francis Ltd., 2016) Niveshika; Savita Singh; Ekta Verma; Arun Kumar Mishra
The present study was focused on the isolation of multiple metal tolerant and antibiotics resistant bacterial strains from water samples of five different Ghats of River Ganga, Varanasi, India. These strains were biochemically characterized and their phylogenetic relatedness was assumed using amplified ribosomal DNA restriction analysis fingerprinting and 16S ribosomal gene sequencing. The presence of heterogeneous groups of bacteria belonging to alpha, beta, gamma proteobacteria, and bacilli was noticed. Some of the bacterial strains like Pseudomonas, Serratia, Enterobacter, and Proteus vulgaris were mainly found at the Dashashwamedh Ghat and the Assi Ghat showing minimum inhibitory concentration 200–300 mg/L for copper, nickel, lead, and chromium. Comamonas sp. mainly isolated from the Samne Ghat and the Rajendra Prasad Ghat was able to grow at very high concentration of lead viz. 400 mg/L. Some of the strains showed multidrug resistant property against 10 different antibiotics which are of most serious concern because these drugs are frequently used against various bacterial infections. © 2017 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license.
Modulation of fatty acids and hydrocarbons in Anabaena 7120 and its ntcA mutant under calcium
(Wiley-VCH Verlag, 2017) Savita Singh; Ekta Verma; Balkrishna Tiwari; N. Niveshika; Arun Kumar Mishra
Calcium being a signaling molecule and mediator of cell response, we examined the modulation in fatty acid and hydrocarbon profiles of wild type cyanobacterium Anabaena sp. PCC 7120 and its ntcA mutant under the influence of different calcium chloride concentrations (0–10 mM). Dynamic modifications in fatty acid and hydrocarbon profile were evident through GC-FID analysis of extracted lipids. In the wild type, increase in CaCl2 (10 mM) resulted in unsaturation of fatty acids (observed in terms of high MUFA/PUFA ratio) while hydrocarbon production was distinctly high in the mutant strain compared to wild type at all tested concentrations. The synthesis of short chain hydrocarbons (C5–C8) were dominated at inhibitory concentration (10 mM CaCl2) in mutant strain. Results suggest that the increase in MUFA/PUFA ratio at inhibitory concentration in wild type, and higher percentage of hydrocarbons in mutant strain, may be attributed to the survival and acclimation strategies under altered calcium environment. Our results also suggest the involvement of the ntcA gene (master regulator of N2 metabolism) in regulation of carbon metabolism; specifically fatty acid, hydrocarbon, and other metabolic compounds essential for maintenance and sustenance of growth under stress condition. Thus, our study outlines basic acclimation response along with possibilities of production of fatty acid and hydrocarbon derived biofuel and other bioactive compounds in Anabaena sp. PCC 7120 under altered calcium levels which could be of biotechnological interest. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Optimizing light regimes for neutral lipid accumulation in Dunaliella salina MCC 43: a study on physiological status and carbon allocation
(Springer Science and Business Media B.V., 2024) Abhishek Mohanta; Nitesh Prasad; Sk Riyazat Khadim; Prabhakar Singh; Savita Singh; Avinash Singh; A.M. Kayastha; R.K. Asthana
Dunaliella salina is a favourable source of high lipid feedstock for biofuel and medicinal chemicals. Low biomass output from microalgae is a significant barrier to industrial-scale commercialisation. The current study aimed to determine how photosynthetic efficiency, carbon fixation, macromolecular synthesis, accumulation of neutral lipids, and antioxidative defence (ROS scavenging enzyme activities) of D. salina cells were affected by different light intensities (LI) (50, 100, 200, and 400 µmol m−2 s−1). The cells when exposed to strong light (400 µmol m−2 s−1) led to reduction in chlorophyll a but the carotenoid content increased by 19% in comparison to the control (LI 100). The amount of carbohydrate changed significantly under high light and in spite of stress inflicted on the cells by high irradiation, a considerable increase in activity of carbonic anhydrase and fixation rate of CO2 were recorded, thus, preserving the biomass content. The high light exposed biomass when subjected to nitrogen-deficient medium led to increase in lipid content (59.92% of the dry cell weight). However, neutral lipid made up 78.26% of the total lipid while other lipids like phospholipid and glycolipid content decreased, showing that the lipid was redistributed in these cells under nitrogen deprivation, making the organism more appropriate for biodiesel/jet fuel use. Although D. salina cells had a relatively longer generation time (3.5 d) than other microalgal cells, an economic analysis concluded that the amount of carotenoid they produced and the quality of their lipids made them more suited for commercialization. Graphical abstract: [Figure not available: see fulltext.] © 2024, The Author(s), under exclusive licence to Springer Nature B.V.
Phytohormone augmented biomass and lipid production in Dunaliella salina under two-stage cultivation strategy: A comprehensive characterization of biomass and lipid using DLS, FTIR, CHNS and NMR for bioenergy prospects
(Elsevier Ltd, 2024) Savita Singh; Avinash Singh; Nitesh Prasad; Sakshi Singh; Ravi Kumar Asthana
Increasing population, climatic shifts, and decreasing fossil-fuels worldwide led scientists to explore microalgae as a renewable energy resource. The present study unravels the impact of gibberellic acid (GA3) on biomass production, enzymatic activities, macromolecular synthesis, and metabolome analysis of Dunaliella salina using two-stage cultivation strategy. The results indicated a marked increase in biomass (1.44-fold), photosynthetic yield (Fv/Fm 0.68), along with RuBisCO activity (1.66-fold), with an increased in absolute value of zeta potential(ζ) in cultures treated with 10 µM GA3 compared to controls (Stage I). Interestingly, 15 µM GA3-treated cells significantly enhanced lipid content (42.36 %), and carbohydrates (16.56 %) with elevated antioxidative enzymes (SOD, CAT, and APX) activities (Stage II). Enhanced lipid content was further confirmed through FTIR spectra (2928 cm-1, and 1740 cm-1) and 1H NMR signals (1.0– 2, 3.5–4.5 ppm), indicating an increase in both saturated (SFA) and polyunsaturated fatty acids (PUFAs). Elemental analysis demonstrated higher carbon and hydrogen percentages, reflected in higher heating value (HHV) and H/C ratio at 15 µM GA3. The increased lipid content was found to be significantly correlated with ACCase and GPAT activities, suggesting the allocation of carbon flux toward lipid biosynthesis pathways. To substantiate the carbon flux, HR-MS-based metabolomic analysis was performed, indicating a reduction in TCA and Calvin cycle intermediates with a significant rise in carotenoid biosynthesis, as well as metabolic shift towards fatty acid biosynthesis reflecting in the enhanced SFA and PUFAs. Thus, these findings highlighted GA3 significant role in the carbon flux allocation towards the neutral lipid biosynthesis for bioenergy prospects. © 2024 Elsevier Ltd
Plant-bacterial interactions and sustainable crop production: Physiological and molecular mechanisms
(Nova Science Publishers, Inc., 2017) Ekta Verma; Savita Singh; N. Niveshika; Sindhunath Chakraborty; Arun Kumar Mishra
In recent days, continuously increasing human population as well as rapid development of industries and multiplexes has limited the space required for agricultural practices throughout the world which has ultimately resulted in reduced crop production. In addition, crop plants that are being cultivated in these limited agricultural lands are also facing a number of environmental constraints such as nutrient scarcity, soil acidity, heavy metal toxicity, pathogen attack, contamination of xenobiotic compounds etc. which are also inhibiting their growth. Hence, it is apparent that crop production all over the world is under serious threat which is weakening the global food security. Therefore, it has become indispensable to increase the crop production rate to meet the need of the ever increasing world population. For this, enhancement of soil fertility or mobilization of already existing soil nutrients is very much important. Bacteria present in soil play an outstanding role in increasing soil fertility and plant growth. Bacteria can also promote plant growth indirectly by protecting the plants from different environmental stresses (biotic and abiotic). So, the scientific exploration of plant growth promoting bacterial strains and their application in the agricultural fields may help to sustain crop production and overcome the problems related to the global food security. The present review describes the role of soil bacterial diversity in sustainable agriculture and the mechanisms used by these beneficial microbes to promote plant growth. A meticulous study of PGPB for their roles in N-fixation, P solubilisation, S oxidation, improving nutrient acquisition by plants, phytostimulation, rhizoremediation, controlling stress as well as production of siderophores, antibiotics, HCN and volatile organic compounds has been presented in this article. Therefore, this review will help to understand the bacterial diversity and their specific plant growth promoting activities with recent progress in the field of agricultural microbiology. © 2017 by Nova Science Publishers, Inc. All rights reserved.
Profenofos induced modulation in physiological indices, genomic template stability and protein banding patterns of Anabaena sp. PCC 7120
(Taylor and Francis Inc., 2016) Balkrishna Tiwari; Sindhunath Chakraborty; Savita Singh; Arun K. Mishra
To understand the mechanism underlying organophosphate pesticide toxicity, cyanobacterium Anabaena PCC 7120 was subjected to varied concentrations (0, 5, 10, 20 and 30 mg L−1) of profenofos and the effects were investigated in terms of changes in cellular physiology, genomic template stability and protein expression pattern. The supplementation of profenofos reduced the growth, total pigment content and photosynthetic efficiency of the test organism in a dose dependent manner with maximum toxic effect at 30 mg L−1. The high fluorescence intensity of 2′, 7′ –dichlorofluorescin diacetate and increased production of malondialdehyde confirmed the prevalence of acute oxidative stress condition inside the cells of the cyanobacterium. Rapid amplified polymorphic DNA (RAPD) fingerprinting and SDS-PAGE analyses showed a significant alteration in the banding patterns of DNA and proteins respectively. A marked increase in superoxide dismutase, catalase, peroxidase activity and a concomitant reduction in glutathione content indicated their possible role in supporting the growth of Anabaena 7120 up to 20 mg L−1. These findings suggest that the uncontrolled use of profenofos in the agricultural fields may not only lead to the destruction of the cyanobacterial population, but it would also disturb the nutrient dynamics and energy flow. © 2016 Taylor & Francis Group, LLC.
Regulation of calcium ion and its effect on growth and developmental behavior in wild type and ntcA mutant of Anabaena sp. PCC 7120 under varied levels of CaCl2
(Maik Nauka Publishing / Springer SBM, 2014) Savita Singh; Arun K. Mishra
A study of calcium ion regulation in Anabaena 7120 and its derivative mutant (CSE2) strain impaired in ntcA gene were investigated in terms of altered morphological and physiological responses against various levels of calcium stress (0-100 mM). Calcium concentration of 10 mM was found to be inhibitory while 100 mM proved lethal for both wild type and mutant strain. The involvement of Ca2+ in the regulation of cellular processes has been described in terms of an influx or efflux of Ca2+ from the cytosol. A biphasic calcium uptake with difference in calcium influx and efflux rate was responsible for differential amount of remaining calcium which followed a decreasing trend both for wild type and mutant. Low Ks0.5 and high Vmax in mutant suggest heavy and less restricted influx of calcium ion. Further, the interactive effect of calcium influx/efflux rate, remaining Ca2+ and intracellular levels of Na+ and K+ may be attributed for the degree of membrane damage and growth sustenance during exogenous supply of calcium salt. Widening in heterocyst spacing pattern, decreased heterocyst frequency and formation of abnormal cell structures at higher concentration (100 mM CaCl2) suggest that calcium mediated regulatory process modulate heterocyst frequency and maintenance of cell structure. Further, poor regulation of calcium ion homeostasis in ntcA suggests that the calcium level and ntcA gene expression are inter-related. © 2014 Pleiades Publishing, Ltd.
Regulation of organophosphate metabolism in cyanobacteria. A review
(Maik Nauka Publishing / Springer SBM, 2015) Balkrishna Tiwari; Savita Singh; Manish Singh Kaushik; Arun Kumar Mishra
Cyanobacteria sense the environmental phosphate level and respond accordingly with the help of a two component regulatory system SphS-SphR orthologous to PhoR-PhoB of E. coli, where SphS act as a sensor kinase and SphR as a response regulator. Under phosphate limiting condition SphS-SphR regulates the expression of many genes including genes which do not have the direct role in metabolism and transport of phosphate. Thus there is some crosstalk mechanism which connects this regulatory system to the other metabolic processes. Different types of enzymes and transporters are expressed by cyanobacteria under phosphate limitation to release and transport the phosphate from different organic compounds present in the environment. Genes encoding these enzymes and transporters contain Pho boxes in their promoter region where SphR binds and regulate their expression under phosphate limitation. The machinery and mechanism of regulation is not uniform in cyanobacteria as it varies in different groups according to their evolutionary adaptations. This review article is summarizing the reports on machinery and mechanism of organophosphate metabolism in cyanobacteria. © 2015, Pleiades Publishing, Ltd.
Sequential role of biosorption and biodegradation in rapid removal degradation and utilization of methyl parathion as a phosphate source by a new cyanobacterial isolate Scytonema sp. BHUS-5
(Taylor and Francis Inc., 2017) Balkrishna Tiwari; Savita Singh; Sindhunath Chakraborty; Ekta Verma; Arun Kumar Mishra
A new isolate of genus Scytonema distinct from its closest relative cyanobacterium, Scytonema hofmanni was found efficient in the removal and degradation of organophosphorus (OP) pesticide, methyl parathion (MP). The cyanobacterial isolate was also capable of utilizing the phosphorus present in the MP following its degradation, which was evident from the increase in growth (chlorophyll content), biomass, protein content, and total phosphorus in comparison to cyanobacterium grown in phosphate-deficient cultures. The rapid removal of MP by the cyanobacterium during initial 6 hours of incubation was defined by the pseudo-second-order biosorption kinetics model, which indicated the involvement of chemosorption in initial removal of pesticide. Further, degradation of MP was also confirmed by the appearance of p-nitrophenol in the medium after 24 hours of incubation. Thus, the cyanobacterial isolate of Scytonema sp. BHUS-5 seems to be a potential bioremediation agent for the removal of OP pesticide, MP from the habitat. © 2017 Taylor & Francis Group, LLC.
Unraveling of cross talk between Ca2+ and ROS regulating enzymes in Anabaena 7120 and ntcA mutant
(Wiley-VCH Verlag, 2016) Savita Singh; Arun Kumar Mishra
In order to understand a cross talk between Ca2+ and ROS regulating enzymes and the possible involvement of ntcA gene, Anabaena sp. PCC 7120 and its derivative ntcA mutant grown in varied levels of calcium chloride (0, 1, 10, and 100 mM) have been investigated. Scanning Electron Microscopy showed abnormal structure formation at high calcium concentration (100 mM) both in wild type and mutant. Fv/Fm values suggested that 100 mM calcium concentration was detrimental for photosynthetic apparatus. SOD, catalase, APX, GR, and peroxidase activity were found to be maximum for 100 mM and minimum for 1 mM of exogenously supplied calcium salt. NADPH contents were higher for wild type than mutant. RAPD-PCR and SDS-PAGE analysis revealed a difference in DNA as well as proteome pattern with changes in calcium chloride regime. Prominent bands of approximately 70, 33, 21, and 14 kDa expressed in the wild type served as the marker polypeptide bands under calcium supplementation. Results suggest that higher levels of calcium ion disturb the cellular homeostasis generating ROS, thereby inducing enhanced levels of antioxidative enzymes. Further, data also suggests possible involvement of ntcA gene in cross talk between calcium ion and ROS regulating enzymes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim