Browsing by Author "Ashish Kumar Srivastava"

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A comparative study of antioxidative defense system in the copper and temperature acclimated strains of Anabaena doliolum
(2008) Yogesh Mishra; Poonam Bhargava; Riti Thapar; Ashish Kumar Srivastava; Lal Chand Rai
This study provides first hand comparative account of growth and antioxidative defense system of the wild type, Cu2+ and temperature treated wild type and acclimated strains of Anabaena doliolum Bharadwaja against Cu2+ and high temperature. The acclimated strains showed perceptible growth at 250 μM Cu2+ and 47°C temperatures, respectively. In contrast to this the wild type strain on exposure to 50 μM Cu2+ and 47°C temperature depicted almost complete inhibition of growth. However, the peroxide content was significantly higher in the acclimated strains than the wild type. Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) showed maximum activity at high temperature followed by Cu2+ acclimated and minimum in the wild type strains. The ascorbate (ASC) and glutathione (GSH) contents were increased by 2.3 and 43.3, and 15.5 and 36.5-fold in Cu2+ and 47°C acclimated strains, respectively. However, when the wild type strain was subjected to Cu2+ and temperature all antioxidative enzymes except SOD showed inhibition of their activity. In case of wild type the GSH content was inhibited by 0.39-fold at 50 μM Cu2+ but the ASC content registered increase by 2 and 2.7-fold on subjecting to Cu2+ and temperature, respectively. Thus increased activity of enzymatic antioxidants as well as accumulation of ascorbate and glutathione in both the acclimated strains suggests that enzymatic and non-enzymatic antioxidants help in the acclimation of A. doliolum Bharadwaja against Cu2+ and high temperature. However, inhibition of antioxidative defense system of wild type under Cu2+ and heat stress appears to be the reason for its non survival. In view of the appreciable increase in the level of antioxidants as well as greater inhibition of specific growth rate in temperature than Cu2+ acclimated strains, temperature (47°C) is proposed to be is more deleterious to the organism than copper (250 μM). © 2008 Springer Science+Business Media B.V.
Antioxidant enzymes and transporter genes mediate arsenic stress reduction in rice (Oryza sativa L.) upon thiourea supplementation
(Elsevier Ltd, 2022) Munish Kumar Upadhyay; Arnab Majumdar; Ashish Kumar Srivastava; Sutapa Bose; Penna Suprasanna; Sudhakar Srivastava
Thiourea (TU) is a chemo-priming agent and non-physiological reactive oxygen species (ROS) scavenger whose application has been found to reduce As accumulation in rice grains along with improved growth and yield. The present field study explored TU-mediated mechanistic changes in silicon (Si) assimilation in root/shoot, biochemical and molecular mechanisms of arsenic (As) stress amelioration in rice cultivars. Gosai and Satabdi (IET-4786) rice cultivars were selected for field experiment at three different places; control field and two other As contaminated experimental fields (EF1 and EF2) in West Bengal, India. The average As reduction was observed to be 9.5% and 19.8% whereas the yield increment was 8.8% and 17.7% for gosai and satabdi, respectively among all the three experimental fields. The positive interrelation was also observed between improved internal ultrastructure anatomy and enhanced Si assimilation (36%–423%) upon TU application. The level of photosynthetic pigments was increased by 29.8%–99.2%. Further, activities of antioxidant enzymes were harmonically altered in TU supplemented plants. The expression of various As related transporter genes in flag leaf and developing grains (inflorescence) was changed in both the rice cultivars (gosai and satabdi). It was also presumably responsible for observed As reduction in grains. Thus, TU application was found to be an efficient and sustainable agronomic practice for amelioration of As toxicity in rice plants in As contaminated field conditions. © 2021
Arsenic dynamics and flux assessment under drying-wetting irrigation and enhanced microbial diversity in paddy soils: A four year study in Bengal delta plain
(Elsevier B.V., 2021) Arnab Majumdar; Munish Kumar Upadhyay; Biswajit Giri; Sudhakar Srivastava; Ashish Kumar Srivastava; Manoj Kumar Jaiswal; Sutapa Bose
Arsenic (As) assessment in agricultural soils and corresponding crops is necessary from the global health safety perspective. To the best of our knowledge, we are reporting for the first time, As flux determining parametric equations for paddy field with seasonal rice cultivation under conventional flooding and dry-wet irrigation approaches. Rigorous field experiments and measuring quantitative parameters, flushed out or percolated into the deeper soil As flux was assessed. A wintery (boro)-monsoonal (aman) study from 2016 to 2019 has been conducted showing the efficiency of dry-wet irrigation on reduction of soil As bioavailability. The reduction in boro was 52.4% in 2016 to 64.8% in 2019 while in aman, it was 61% in 2016 to 74.9% in 2019. Low bioavailability was correlated to plant's internal vascular structure that was found more rigid and firm in dry-wet field grown plants. Observed soil physico-chemical parameters clearly influenced As bioavailability as well as soil microbial community. Assessment of microbial diversity using metagenomics under altered water regime was done by population analysis, relative abundance, species richness, Krona chart comparison. Dry-wet field was found to be more diverse and enriched in microbial community than that of the flooded soil indicating an affective reduction of As bioavailability under biotic-abiotic factors. © 2020 Elsevier B.V.
Cellular and subcellular phosphate transport machinery in plants
(MDPI AG, 2018) Sudhakar Srivastava; Munish Kumar Upadhyay; Ashish Kumar Srivastava; Mostafa Abdelrahman; Penna Suprasanna; Lam-Son Phan Tran
Phosphorus (P) is an essential element required for incorporation into several biomolecules and for various biological functions; it is, therefore, vital for optimal growth and development of plants. The extensive research on identifying the processes underlying the uptake, transport, and homeostasis of phosphate (Pi) in various plant organs yielded valuable information. The transport of Pi occurs from the soil into root epidermal cells, followed by loading into the root xylem vessels for distribution into other plant organs. Under conditions of Pi deficiency, Pi is also translocated from the shoot to the root via the phloem. Vacuoles act as a storage pool for extra Pi, enabling its delivery to the cytosol, a process which plays an important role in the homeostatic control of cytoplasmic Pi levels. In mitochondria and chloroplasts, Pi homeostasis regulates ATP synthase activity to maintain optimal ATP levels. Additionally, the endoplasmic reticulum functions to direct Pi transporters and Pi toward various locations. The intracellular membrane potential and pH in the subcellular organelles could also play an important role in the kinetics of Pi transport. The presented review provides an overview of Pi transport mechanisms in subcellular organelles, and also discusses how they affect Pi balancing at cellular, tissue, and whole-plant levels. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
Chemical intervention for enhancing growth and reducing grain arsenic accumulation in rice
(Elsevier Ltd, 2021) Ashish Kumar Srivastava; Manish Pandey; Tejashree Ghate; Vikash Kumar; Munish Kumar Upadhyay; Arnab Majumdar; Abhay Kumar Sanjukta; Ashish Kumar Agrawal; Sutapa Bose; Sudhakar Srivastava; Penna Suprasanna
Thiourea supplementation downregulated aquaporins to restrict arsenic accumulation in seedlings. Foliar-applied thiourea enhanced yield and reduced grain arsenic accumulation. © 2021 Elsevier Ltd; Arsenic (As) is a ubiquitous environmental carcinogen that enters the human food chain mainly through rice grains. In the present study, we evaluated the potential of thiourea (TU; non-physiological reactive oxygen species scavenger) in mitigating the negative effects of arsenic (As) stress in indica rice variety IR64, with the overall aim to reduce grain As accumulation. At seedling stage, As + TU treatment induced the formation of more numerous and longer crown roots compared with As alone. The As accumulation in main root, crown root, lower leaf and upper leaf was significantly reduced to 0.1-, 0.14-, 0.16-, 0.14-fold, respectively in As + TU treated seedlings compared with those of As alone. This reduced As accumulation was also coincided with light-dependent suppression in the expression levels of aquaporins and photosynthesis-related genes in As + TU treated roots. In addition, the foliar-supplemented TU under As-stress maintained reducing redox conditions which decreased the rate of As accumulation in flag leaves and, eventually grain As by 0.53-fold compared with those of As treatment. The agronomic feasibility of TU was validated under naturally As contaminated sites of Nadia (West Bengal, India). The tiller numbers and crop productivity (kg seed/ha) of TU-sprayed plants were increased by 1.5- and 1.18-fold, respectively; while, grain As accumulation was reduced by 0.36-fold compared with those of water-sprayed control. Thus, this study established TU application as a sustainable solution for cultivating rice in As-contaminated field conditions. © 2021 Elsevier Ltd
Combined effects of dry-wet irrigation, redox changes and microbial diversity on soil nutrient bioavailability in the rice field
(Elsevier B.V., 2023) Arnab Majumdar; Pradeep Kumar Dubey; Biswajit Giri; Debojyoti Moulick; Ashish Kumar Srivastava; Tarit Roychowdhury; Sutapa Bose; Manoj Kumar Jaiswal
Sustainable development goals (SDGs) by United Nations are some of the high-priority areas of research and this article established the sustainable agronomic practices converging soil chemistry, crop productivity and soil microbial involvement in nutrient modulation. Alternate wetting-drying (AWD) cultivation with implications on soil microbiome, nutritional dynamics and rice yield during pre-monsoon (boro) and monsoon (aman) season are not well studied. In the present 4-year field study, the impact of AWD irrigation in pre-monsoon and flooded irrigation in monsoon on soil microbiota and the nutrient pool has been studied. Nutrient-less pond water has been used to avoid any external nutrient input from irrigation water to ensure the sole elemental flux within the soil itself. The release of soil nutrients into the soil-aqueous system, influencing microbial populations and modulating the redox status was explored. Results indicated an increase in total concentration as well as bioavailability of selected nutritional elements (N, P, K, Fe, Ca, Mg, Cu and Zn) by 16–54% in the pre-monsoon cultivation relative to monsoon cultivation. Three plant growth phases (developing, milking and harvest) were considered to check the nutrient modulations in soil and plant tissues along with the plant growth and elemental uptake continuum. Crop plant measurements were improved and grain yields were found to be 5.2–6.46% increased under AWD and microbial activity. Krona charts, relative abundance, rarefaction curve and multivariate analysis of metagenomics data showed that the pre-monsoon soil was more enriched and maintained a balance between soil pH and microbial biomass than the monsoon soil. Microbial community diversity associated with plant growth phases was also found to be different depending on the seasonal alterations. Bacillus sp., Acidothiobacillus sp., Pseudomonas sp., Rhizobium sp., Burkholderia sp. were predominant in pre-monsoon soil releasing pulses of N, P, K, Ca and Mg whereas Verrucomicrobia was found to be dominant in monsoon soil where Fe was released. This study is a first of its kind that showed the combined effect of season and some specific groups of soil microbes on macro-micro nutritional availability in soil and enhanced plant quality. © 2023 Elsevier B.V.
Differential response of antioxidative defense system of Anabaena doliolum under arsenite and arsenate stress
(2009) Ashish Kumar Srivastava; Poonam Bhargava; Riti Thapar; Lal Chand Rai
This study offers first hand information on the arsenite (As(III)) and arsenate (As(V))-induced oxidative tress and changes in antioxidative defense system of Anabaena doliolum. A requirement of 58 mM As(V) as compared to only 11 mM As(III) to cause 50% reduction in growth rate suggests that As(III) is more toxic than As(V) in the test cyanobacterium. In contrast to above, oxidative damage measured in terms of lipid peroxidation, electrolyte leakage and peroxide content were significantly higher after As(V) than As(III) treatment as compared to control. Similarly all the studied enzymatic parameters of antioxidative defense system except glutathione reductase (GR) and non-enzymatic parameters except glutathione reduced (GSH) showed greater induction against As(V) than As(III). Interestingly, higher increase in non-enzymatic counterpart than enzymatic in both the stresses suggests that detoxification is mainly managed by former than the later. This confirms the belief of pronounced stimulation of the antioxidative defense system by As(V) than As(III). In conclusion, the cyanobacterium may survive better in As(V) than As(III) contaminated fields because of its low toxicity and pronounced induction of antioxidative defense system. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
DNA cleavage activity and cytotoxicity of mononuclear and trinuclear Cu(II) complexes containing 1H-pyrazole-3,5-dicarboxylic acid as ligand
(2013) Ashish Kumar Srivastava; Niraj Kumari; Rais Ahmad Khan; Richa Rai; Geeta Rai; Sartaj Tabassum; Lallan Mishra
UV-vis titrations of complexes [Cu(H2pdc)2(H 2O)2] (1) and [Cu3(pdc)2(bpy) 2(H2O)4] (2) (H3pdc=1H-pyrazole-3,5- dicarboxylic acid, bpy=2,2' bipyridine) with calf thymus DNA demonstrate their moderate binding with DNA. Fluorescence titrations show significant displacement of ethidium bromide bound to DNA by the complexes. Agarose gel electrophoretic mobility assay indicates that the complexes are able to cause concentration-dependent nicking of supercoiled DNA under physiological conditions. Ligation experiments with T4 DNA ligase enzyme show that the nicked DNA cleavage products generated by complexes (1) and (2) is religated to a large extent in the presence of T4 ligase enzyme. Complex (2) shows potential cytotoxicity against CaSki cervical cancer, HL-60 leukemic cell lines and THP-1 human monocytic cell lines with IC50 value of 1.5 μM, 2.5 μM and 10 μM respectively. A redox inactive Zn(II) complex of type [Zn(H 2pdc)2(H2O)2]· H2O (3) was also synthesized and characterized but owing to its poor solubility, further studies could not be carried out.
Effect of nitrate seed priming on phenology, growth rate and yield attributes in rice (Oryza sativa L.)
(2012) Ashish Kumar Srivastava; Bandana Bose
To investigate the effect of seed priming with or without nitrate salts (Mg (NO3) 2 and KNO3) in some rice varieties on mobilization of dry matter to yield components, a field experiment was carried out in two consecutives years, 2006 and 2007 at Agricultural Farm of Banaras Hindu University, Varanasi, India. Dry matter mobilization had an important effect on grain yield in all used rice varieties. The amount of dry matter however accumulated in reproductive parts, different under different priming treatments and varieties, was found better in nitrate primed sets. Varietal difference in grain yield was most closely related with Crop Growth Rate (CGR) during late reproductive period. The rice varieties having higher CGR during this period produced a greater number of spikelets and filled grains per unit land area. Simultaneously, lower number of half filled and chalky spikeletes was produced in all the primed sets. The large variability in various primed sets as compared to non primed one in CGR during the late reproductive period and protein content in grain at harvest might be derived from greater absorption of nutrient, water, further produced photosynthate and their translocation towards reproductive parts. These results indicated that improvement in yield determining parameters by using of seed priming particularly with nitrate sets may be essential as a first step towards increasing yield potential in rice in India.
Effect of pretreatment of salt, copper and temperature on ultraviolet-B-induced antioxidants in diazotrophic cyanobacterium Anabaena doliolum
(2006) Ashish Kumar Srivastava; Poonam Bhargava; Yogesh Mishra; Bideh Shukla; Lal Chand Rai
Effect of salt, copper, and temperature pretreatments on the UV-B-induced oxidative damage, measured in terms of peroxide and MDA (lipid peroxidation) contents, was studied in the diazotrophic cyanobacterium Anabaena doliolum. To understand the survival strategy enzymatic (superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (glutathione, ascorbate, α-tocopherol and carotenoid) antioxidants were studied. Among the various pretreatments salt was found to decrease and copper and temperature pretreatments increased the deleterious effects of UV-B. This study is the first to demonstrate that physical stress (high temperature) enhanced the damaging effect of UV-B more profoundly than chemical stresses (salt and copper). © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.
Excess copper induces anoxygenic photosynthesis in Anabaena doliolum: A homology based proteomic assessment of its survival strategy
(2008) Poonam Bhargava; Yogesh Mishra; Ashish Kumar Srivastava; Om Prakash Narayan; Lal Chand Rai
This study is the first to demonstrate operation of anoxygenic photosynthesis in copper acclimated Anabaena doliolum and to offer proteomic comparison with the control cells. The Cu-treated control strain showed a negative correlation in growth and intracellular Cu, partial inhibition of O2-evolution, PS II, PS I, whole chain, chlorophyll absorption, and nitrogenase activity. However, the acclimated strain growing in 250-fold excess Cu exhibited near normal growth, ATP content, PS I activity, carbon fixation, and almost complete inhibition of O2-evolution, PS II and chlorophyll absorption, but increased nitrogenase activity as compared to control. Proteomic decoding of the survival strategy of Cu-treated control and the acclimated strain using two-dimensional gel electrophoresis and MALDI-TOF MS analysis of proteins displaying significant and reproducible changes demonstrated involvement of transketolase, phycoerythrocyanin α-chain, iron superoxide dismutase (Fe-SOD), hypothetical protein alr 0803, manganese superoxide dismutase (Mn-SOD), phosphoribulokinase, and plastocyanin (PLC). Expression pattern of these proteins was attested at the transcriptional level using RT-PCR. Time course analysis of proteins of Cu-treated control strain revealed almost no change in PLC level, and a minor accumulation of transketolase, phycoerythrocyanin α-chain and both isoforms of SOD after 7 and recovery after 10 days. Acclimated strain under excess Cu, however, exhibited significant accumulation of both isoforms of SOD, plastocyanin, phosphoribulokinase and transketolase, which seem to counteract oxidative damage, serve as an alternate electron carrier from cytochrome b6/f complex to photosystem I and meet the NADPH and ATP requirements, respectively, under anoxygenic photosynthesis. In view of the kinetics of the hypothetical protein alr0803 (no change in expression level for 7, maximum after 10 and decline after 15 days) its involvement in metal homeostasis is suggested. © 2007 Springer Science+Business Media B.V.
Impact of different abiotic stresses on growth, photosynthetic electron transport chain, nutrient uptake and enzyme activities of Cu-acclimated Anabaena doliolum
(Elsevier GmbH, 2008) Riti Thapar; Ashish Kumar Srivastava; Poonam Bhargava; Yogesh Mishra; Lal Chand Rai
This study provides a comparative account of the effects of cadmium, temperature, ultraviolet-B and sodium chloride on the growth, photosynthesis, nutrient uptake and enzyme activities of untreated control and copper-acclimated Anabaena doliolum. Reduction in all the studied parameters, except carotenoids, was maximum for sodium chloride followed by ultraviolet-B, temperature and cadmium treatments, the reduction being greater in control than acclimated A. doliolum. Among the various parameters, photosystem II was most sensitive for all the stresses in both control and acclimated A. doliolum. Likewise, O2 evolution was more susceptible to various stressors than 14C uptake. Ammonium uptake and glutamine synthetase (GS, EC 6.3.1.2) were the least affected parameters. As compared to control, acclimated Anabaena exhibited higher ATP content under normal conditions. These results attest our hypotheses that acclimated Anabaena was physiologically more robust than control and that salinity was more injurious to the test organism than other abiotic stresses investigated. © 2007 Elsevier GmbH. All rights reserved.
Molecular approaches towards assessment of cyanobacterial biodiversity
(2009) Nidhi Kumari; Ashish Kumar Srivastava; Poonam Bhargava; Lal Chand Rai
Cyanobacteria, a diverse group of photosynthetic prokaryotes, often play central roles in carbon and nitrogen assimilation which makes their environment productive. Despite their significant agronomic values, biodiversity assessment and conservation of these important microbes have not been given much attention by researchers. This review tries to bring together the important aspects of molecular approaches being used for cyanobacterial biodiversity assessment. Molecular approaches have been divided into 2 classes: PCR independent and PCR based approaches. While the former includes guanine plus cytosine (G+C) content, nucleic acid re-association and hybridization and DNA microarrays, the latter basically uses DNA cloning and sequencing, DGGE (denaturing gradient gel electrophoresis), TGGE (temperature gradient gel electrophoresis), SSCP (single strand conformation polymorphism), RFLP (restriction fragment length polymorphism), ARDRA (amplified ribosomal DNA restriction analysis), T-RFLP (terminal restriction fragment length polymorphism), RISA (ribosomal intergenic spacer analysis), ARISA (automated ribosomal intergenic spacer analysis) and RAPD (random amplified polymorphic DNA). Molecular assessment of cyanobacterial biodiversity frequently uses markers like 16S rDNA, phycocyanin locus, nif gene, rpo gene, ITS region etc. This article examines and compares various conventional and modern methods and their short comings, if any. It attempts to provide a general overview of biodiversity assessment, molecular techniques and markers used for biodiversity assessment and also recommends combinatorial approach with different molecular markers. It is likely to improve the degree of resolution and provide as possible the broadest picture and indepth information about biodiversity documentation. © 2009 Academic Journals.
Molecular characterization and the effect of salinity on cyanobacterial diversity in the rice fields of Eastern Uttar Pradesh, India
(2009) Ashish Kumar Srivastava; Poonam Bhargava; Arvind Kumar; Lal Chand Rai; Brett A Neilan
Background. Salinity is known to affect almost half of the world's irrigated lands, especially rice fields. Furthermore, cyanobacteria, one of the critical inhabitants of rice fields have been characterized at molecular level from many different geographical locations. This study, for the first time, has examined the molecular diversity of cyanobacteria inhabiting Indian rice fields which experience various levels of salinity. Results. Ten physicochemical parameters were analyzed for samples collected from twenty experimental sites. Electrical conductivity data were used to classify the soils and to investigate relationship between soil salinity and cyanobacterial diversity. The cyanobacterial communities were analyzed using semi-nested 16S rRNA gene PCR and denaturing gradient gel electrophoresis. Out of 51 DGGE bands selected for sequencing only 31 which showed difference in sequences were subjected to further analysis. BLAST analysis revealed highest similarity for twenty nine of the sequences with cyanobacteria, and the other two to plant plastids. Clusters obtained based on morphological and molecular attributes of cyanobacteria were correlated to soil salinity. Among six different clades, clades 1, 2, 4 and 6 contained cyanobacteria inhabiting normal or low saline (having EC < 4.0 ds m-1) to (high) saline soils (having EC > 4.0 ds m-1), however, clade 5 represented the cyanobacteria inhabiting only saline soils. Whilst, clade 3 contained cyanobacteria from normal soils. The presence of DGGE band corresponding to Aulosira strains were present in large number of soil indicating its wide distribution over a range of salinities, as were Nostoc, Anabaena, and Hapalosiphon although to a lesser extent in the sites studied. Conclusion. Low salinity favored the presence of heterocystous cyanobacteria, while very high salinity mainly supported the growth of non-heterocystous genera. High nitrogen content in the low salt soils is proposed to be a result of reduced ammonia volatilization compared to the high salt soils. Although many environmental factors could potentially determine the microbial community present in these multidimensional ecosystems, changes in the diversity of cyanobacteria in rice fields was correlated to salinity.
Phytochelatin plays a role in UV-B tolerance in N2-fixing cyanobacterium Anabaena doliolum
(Elsevier GmbH, 2005) Poonam Bhargava; Ashish Kumar Srivastava; Snigdha Urmil; Lal Chand Rai
To study the role of Cd-induced phytochelatins in UV-B tolerance, lipid peroxidation, antioxidative enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase), glutathione and phytochelatin contents were measured in buthionine sulphoximine treated and untreated cells of Anabaena doliolum. Cd-pretreatment of the cyanobacterium reduced the lipid peroxidation as well as the antioxidative enzymes in comparison to UV-B treatment alone, whereas the phytochelatin content demonstrated an increase. In contrast to this, buthionine sulphoximine-induced inhibition of phytochelatin synthase, dramatically decreased the Cd-induced co-tolerance against UV-B, hence demonstrating that phytochelatin not only protects the cyanobacterium from heavy metal but participates in UV-B tolerance as well. © 2005 Elsevier GmbH. All rights reserved.
Preliminary analysis of cuprome of Anabaena doliolum using two-dimensional gel electrophoresis
(2006) Poonam Bhargava; Yogesh Mishra; Ashish Kumar Srivastava; Anjum Ara; Lal Chand Rai
This study provides first-hand information on the initial characterization of copper-induced changes in the global proteome (hereafter called cuprome) of Anabaena doliolum subjected to short- and long-term treatments. PD Quest analysis revealed that out of 215 protein spots in the control, 79 showed alterations (26 up- and 36 down-regulation, and 5 up- and 12 down-regulation respectively, after 24 and 168 h of Cu treatment) in their expression pattern. The short-term (24 h) and long-term (168 h) treatments induced respectively, 158 and 96 proteins. Of the 158 newly induced proteins, 30 were found to sustain the long-term treatment. In view of the appearance of two sets of proteins, there appears a need to carry out short- and long-term proteome analysis for getting a holistic view of the proteome of cyanobacteria subjected to abiotic stress.
Pyridyl substituted 4-(1,3-Dioxo-1H,3H-benzo[de]isoquinolin-2-ylmethyl)-benzamides with aggregation enhanced emission and multi-stimuli-responsive properties
(Elsevier B.V., 2017) Ashish Kumar Srivastava; Alok Kumar Singh; Niraj Kumari; Richa Yadav; Antonino Gulino; Adolfo Speghini; Rajamani Nagarajan; Lallan Mishra
1,8-Naphthalimide connected to benzoic acid chloride via methylene group was condensed separately with 3-amino pyridine and 4-amino pyridine and provided compounds 4-(1,3-Dioxo-2,3-dihydro-1H-phenalen-2-ylmethyl)-N-pyridin-3-yl-benzamide 1 and 4-(1,3-Dioxo-2,3-dihydro-1H-phenalen-2-ylmethyl)-N-pyridin-4-yl-benzamide 2. The compounds are characterized by spectral (IR, UV–Visible, 1H and 13C NMR) measurements and supported by their X-ray crystallography. Their photoelectron spectroscopy, SEM and TEM measurements are also made. They are found luminescent in DMF solution as well as in the solid state and form nano-aggregates with enhanced emission (AEE) in aqueous-DMF solution. Their AEE behavior depends on the polarity of the solvents. On grinding, crystalline solids 1 and 2 turn to amorphous and the process is reversible on annealing as supported by their powder X-ray diffraction (PXRD) measurements. Both compounds show mechanochromic properties and display multi-stimuli response. Density Functional Theory calculations rationalize their optical data. © 2016 Elsevier B.V.
Rhodamine hydrazone as OFF-ON-OFF type selective sequential sensor of Al3+ and N3- ions
(Elsevier, 2016) Abhishek Rai; Niraj Kumari; Ashish Kumar Srivastava; Sandeep Kumar Singh; Saripella Srikrishna; Lallan Mishra
A new rhodamine hydrazone obtained by the condensation of rhodamine hydrazide with 5-iodo-3-methoxy salicylaldehyde (NLAC) is synthesized and characterized using spectroscopic (IR, UV-vis, 1H, 13CNMR, ESI-MS) and X-ray diffraction techniques. It binds selectively with Al3+ ions and a strong fluorescence signal is displayed from [NLAC - Al3+] ensemble and has also been supported by DFT calculation. The color change of NLAC in presence of Al3+ ions is further corroborated by UV-visible and fluorescence spectral titrations. The spectral changes are significant in the visible region of the spectrum and enable the detection of Al3+ ions with naked eye. The 1:1 stoichiometry of NLAC:Al3+ is supported by Job's plot and ESI-MS data. The fluorescence signal displayed from [NLAC - Al3+] is quenched on the addition of N3- ions as an aqueous solution of NaN3 salt which reverts back further on the addition of Al3+ ions. This recognition process is also displayed in a human cervical cancer cell lines (SiHa cells) in an aqueous-acetonitrile medium. The process is repeated several times showing that the system is robust and reversible in the recognition process. A strip tests supports its feasibility for the laboratory demonstration. © 2016 Elsevier B.V. All rights reserved.
Salinity and copper-induced oxidative damage and changes in the antioxidative defence systems of Anabaena doliolum
(2005) Ashish Kumar Srivastava; Poonam Bhargava; Lal Chand Rai
This study provides first-hand information on the salinity and copper-induced oxidative damage and its protection in Anabaena doliolum by the antioxidant defence system. Oxidative damage measured in terms of lipid peroxidation, electrolyte leakage and H2O2 production was induced by different concentrations of NaCl and Cu2+. A greater electrolyte leakage by NaCl than Cu2+ supported the hypothesis of salinity being more injurious than copper. To explore the survival strategies of A. doliolum under NaCl and Cu stress, enzymatic antioxidant activities e.g. superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) and nonenzymatic antioxidant contents such as glutathione reduced (GSH), ascorbate, α-tocopherol, and carotenoid were measured. A general induction in SOD and APX activities as well as ascorbate and α-tocopherol contents was found under NaCl and Cu2+ stress. In contrast to this, an appreciable decline in GR activity, GSH pool and carotenoid content under Cu2+ and an increase under NaCl stress were observed. CAT activity was completely inhibited at high doses of NaCl but stimulated following Cu2+ treatment. The above results suggest the involvement of APX and CAT in the scavenging of H2O2 under Cu2+ stress. In contrast to this, only APX was involved in H 2O2 scavenging under salt stress. Our postulate of Cu 2+-mediated antagonism of salt stress can be explained by a conceivable reversion of Na+-induced disturbance of cellular homeostasis by redox active Cu2+. © Springer 2005.
Seed priming with salts of nitrate enhances nitrogen use efficiency in rice
(Society for Plant Research, 2017) Ashish Kumar Srivastava; Anaytullah Siddique; Manoj Kumar Sharma; Bandana Bose
An experiment was conducted to investigate the absorption and utilization of nitrogen by rice seed treatment with Nitrate salts (halo priming) and distilled water (hydro-priming) in two successive years. Results revealed that seed priming with Mg (NO3)2, KNO3 and Distilled water always perform better than non-primed control sets in enhancing seed germination and nitrate reductase enzyme activity in leaves that promote to nitrogen accumulation in different plant parts. This seed priming technique further enhanced soluble and insoluble nitrogen content in seed, and also the nitrogen gathering capacity in seed and straw (Kg h-1). Seed priming was also found beneficial in encouraging grain yield after applying Kg-1 nitrogen in the soil. This technique proved promising in more nitrogen accumulation and less nitrogen loss. Among seed priming treatment Mg (NO3)2 performed the best in respect to all measured parameters followed by KNO3 and hydro-primed one in comparison to control sets. These results clearly indicated that higher yield in rice can be achieved via improving the nitrogen absorption and utilization by growing crop, raised with seed priming treatment especially using Mg (NO3)2 salts. © 2017, SciTechnol, All Rights Reserved.