Browsing by Author "Gautam Kumar"

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A chromogenic diarylethene-based probe for the detection of Cu2+ in aqueous medium in Drosophila for early diagnosis of Alzheimer
(Elsevier Ltd, 2024) Gautam Kumar; Ananya Srivastava; Prabhat Kumar; S. Srikrishna; Vinod P. Singh
A diarylethene-based probe (Z)-N'-((2-amino-5-chlorophenyl)(phenyl)methylene)-2-hydroxy benzohydrazide (KBH) has been proficiently developed and its structure has been confirmed by single crystal X-ray diffraction technique. It displays a selective and sensitive colorimetric sensing of Cu2+ ions in aqueous medium with a naked eye colour change from colourless to yellow. It exhibits a significantly low limit of detection as 1.5 nM. A plausible binding mechanism has been proposed using Job's plot, FT-IR, 1H NMR titration, HRMS and DFT studies. The chemosensor is effectively reversible and reusable with EDTA. Test strip kit and real water sample analysis have been shown to establish its practical applicability. Further, the potential of KBH for the early diagnosis of Cu2+ ion-induced amyloid toxicity has been investigated in eye imaginal disc of Alzheimer's disease model of Drosophila 3rd instar larvae. The in-vivo interaction of KBH with Cu2+ in gut tissues of Drosophila larvae establishes its sensing capability in biological system. Interestingly, the in-vivo detection of Cu2+ has been done using bright field imaging which eliminates the necessity of a fluorescent label, hence making the method highly economical. © 2024
A reversible and selective chromogenic thiazole tagged chemosensor for Hg2+in aqueous medium: Crystal structure, theoretical investigations and real sample analysis
(Elsevier B.V., 2023) Gautam Kumar; Ananya Srivastava; Sarita Gond; Pranjalee Yadav; Aayoosh Singh; Vinod P. Singh
A novel thiazole tagged Schiff base chemosensor, (E)-N'-((2-aminothiazol-5-yl)methylene)-2-hydroxybenzohydrazide (ATH) has been synthesized in excellent yield by a simple one pot method and characterized by single crystal X-ray diffraction and spectroscopic techniques. The sensing ability of ATH was determined for detection of Hg2+ ions in the presence of different metal ions in aqueous medium. It behaves as an extremely selective and sensitive chromogenic sensor for naked-eye detection of Hg2+ ions with a colour change from colourless to yellow due to ligand to metal charge transfer. Remarkably, the binding constant (Ka) and limit of detection (LOD) for ATH[sbnd]Hg2+ complex were found as 1.75 × 104 M −1 and 8.85 × 10−7 M, respectively. The Job's plot indicated that the stoichiometric ratio of ATH to Hg2+ is 1:1. The binding mechanism was established based on FT-IR, 1H NMR titration, mass spectrometry and density functional theory studies. The chemosensor exhibited an excellent colorimetric property in 7.0–12.0 pH range. The chemosensor was found to be reversible and reusable in the presence of CN− ions with logic gate behaviour. Further, the chemosensor was utilized to sense Hg2+ ions in tap and Ganga river water samples. © 2023 Elsevier B.V.
Anthracene appended AIEgen as a reversible fluorescence sensor for hazardous cyanide ion in environmental samples and fabrication of portable test kit for on spot detection
(Elsevier B.V., 2025) Pranjalee Yadav; Aayoosh Singh; Gautam Kumar; Saumya Singh; Vinod Prasad Singh
CN− is a frequently encountered pollutant in water and soil. Due to its extreme lethal effect on mammals, serious consideration and efforts are needed for monitoring this hazardous anion. To address this challenge, herein, an anthracene-appended AIEgen (ACFH) has been synthesized and developed for selective fluorometric detection of CN− ion. The detection limit of the probe has been found to be 3.42 × 10−7 M (8.89 ppb), which is much lower than WHO standard (2.7 × 10−6 M). The interaction with CN− causes deprotonation of the probe and subsequent loss of planarity, which has been thoroughly confirmed from 1H NMR titrations and DFT calculations. The reversibility and reusability of ACFH and corresponding logic gates enhance its sensing performance and efficacy. Notably, it has been utilized to meritoriously quantify CN− in various water samples and the fabrication of a portable test kit for monitoring CN− in real time. In addition, the aggregation induced emission (AIE) property has been precisely explored with the aid of fluorescence spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), fluorescence quantum yield and lifetime analysis. © 2024 Elsevier B.V.
Effect of stage-specific and multi-stage drought on grain nutrient quality in rice
(Springer Science and Business Media B.V., 2023) Sahana Basu; Shashi Shekhar; Alok Kumar; Surbhi Kumari; Nitu Kumari; Sonal Kumari; Santosh Kumar; Ram Prasad; Gautam Kumar
Drought is a multidimensional stress that affects the grain nutritional quality of high yielding rice genotypes. The present study evaluated the impacts of stage-specific (seedling, vegetative, and reproductive stages) and cumulative (multi-stage) drought on ionome, starch, and protein contents in grains of two rice genotypes of eastern Indo-Gangetic plain, viz. Sahbhagi Dhan and IR64 with contrasting drought tolerance. The study showed drought to negatively affect the physiological and nutritional traits of rice grains. Following the study, stage-specific and multi-stage drought caused significant reduction in grain size, test weight, starch, amylose, amylopectin, and total soluble protein contents of rice grains. Drought during different developmental stages of rice caused significant variations in micro- (Cu, Fe, Mn, Na, Zn) and macro-nutrient (P, K, Ca, Mg) contents in the grains. Stage-specific and cumulative drought exposure of the rice genotypes also governed the ionomes in grains resulting in specific ionomic networks. Hierarchical cluster analysis showed two discrete clusters for elements as well as different drought treatments in the studied rice genotypes, which supported the results obtained from the principal component analysis, displaying five clusters based on stage-specific and multi-stage drought treatments. Variation in drought treatments and elements in different rice genotypes also altered the ionomic interactions represented by differential ionomic networks. In this study, Sahbhagi Dhan maintained the morphological and nutritional qualities of grains across the drought treatments and therefore, can be used as a suitable donor in breeding for stage-specific and cumulative drought tolerance with superior grain quality for eastern Indo-Gangetic plain. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.
Effective antioxidant defense prevents nitro-oxidative stress under arsenic toxicity: A study in rice genotypes of eastern Indo-Gangetic plains
(Elsevier B.V., 2022) Alok Kumar; Sahana Basu; Surbhi Kumari; Shashi Shekhar; Gautam Kumar
Arsenic (As) toxicity in humans and animals has become a major concern in the last few decades. Rice growing on As-contaminated soil is the principal dietary source of As that poses a significant health hazards to rice patrons, making it a global issue of concern to take necessary steps to counteract the problem. Eastern Indo-Gangetic plains (EIGP) is one of the world's hotspot for As pollution. Arsenic contaminated irrigation is the principal reason for elevated As levels in the agricultural fields of EIGP, which affects rice productivity. The present study intended to explore the influences of As toxicity (arsenite and arsenate) on the morpho-physiology, ionomics, and biochemical performances of 18 rice genotypes of EIGP at the seedling stage. Arsenic exposure negatively affected plant height, root length, and biomass in rice. It also induced membrane degradation thereby, decreasing total chlorophyll content. It also impaired the nutrient uptake and root-to-shoot translocation abilities of plants. Arsenic toxicity led to the accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) consequently, inducing nitro-oxidative stress in rice. Arsenic tolerance in rice was related to the antioxidant defense system that decreased the malondialdehyde (MDA) content and improved the membrane stability thereby, sustaining plant growth. Additionally, proline facilitated ROS eradication conferring protection against the As-induced nitro-oxidative stress. In this study genotypic variation was obvious in all traits associated with As toxicity. Among the rice genotypes studied, Sahbhagi Dhan and Sabour Ardhjal displayed considerably higher As tolerance with sustainable plant growth, membrane stability, nutrient homeostasis, enhanced antioxidant enzyme activities, lower ROS/RNS and MDA accumulations under different As treatments. Overall, the study revealed the association between proteomic and ionomic profiles in rice to understand the potential adaptive mechanisms in plants under As toxicity. © 2022 Elsevier B.V.
Enhanced corrosion resistance of low alloy steel in NaCl environment using 3-substituted chromone derivatives in epoxy coatings
(Elsevier B.V., 2025) Meenakshi Sharma; Meenakshi Thakran; Rakesh Kumar Tiwari; Gautam Kumar; Vinod Prasad Singh; Suman Lata; Sumit Kumar
This study investigates the corrosion-controlling impact of newly synthesized 3-substituted chromone derivatives incorporated as eco-friendly additives in epoxy coatings to improve the corrosion resistance of low alloy steel (LAS) exposed to a corrosive 3.5 % NaCl solution. This is the first time, as far as we know, that such a chromone-based compound has been investigated for use in coatings, marking a significant advancement from traditional toxic corrosion inhibitors to environmentally benign alternatives. The novel chromone derivates were characterized by 1H NMR, 13C NMR, and FT-IR. 3-substituted chromone derivates were applied to LAS substrates and evaluated for their corrosion protection using electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization techniques(PDP) at 298 K at various concentrations (0.25 %, 0.50 %, and 1.00 %), where 0.25 wt% were identified as an optimized concentration for all compounds. Furthermore, EIS and potentiodynamic polarization studies of the various formed coatings also revealed that 0.25 % of (E)‑prop-2-yn-1-yl 3-(7‑hydroxy-4-oxo-4H-chromen-3-yl) acrylate (MSC-5) was the most optimized coating, with an outstanding protection efficacy of 96.91 % even after 336 h of immersion in a 3.5 % NaCl solution. An improvement attributed to the presence of phenolic -OH in MSC-5 enhanced the adhesion and barrier properties of the coating. Contact angle measurements demonstrated the hydrophobicity order of the BS < Epoxy < MSC < MSC-4 < MSC-5-containing coating and highlighted their efficacy as a moisture-resistant barrier. Atomic Force Microscopy (AFM) and FESEM analyses further illustrated the homogeneous dispersion of MSC-5 within the epoxy matrix, with minimal pores or microcracks, thus contributing to the coating's integrity and corrosion resistance. Furthermore, the protective properties of the coating were reinforced by the donor-acceptor interaction using density functional theory. © 2024 Elsevier B.V.
Fluorescent Turn-On Anthracene-Based Aluminum(III) Sensor for a Therapeutic Study in Alzheimer’s Disease Model of Drosophila
(American Chemical Society, 2023) Gautam Kumar; Ananya Srivastava; Prabhat Kumar; S. Srikrishna; Vinod P. Singh
A new anthracene-based probe (E)-N′-(1-(anthracen-9-yl)ethylidene)-2-hydroxybenzohydrazide (AHB) has been efficiently synthesized and characterized by various spectroscopic methods. It exhibits extremely selective and sensitive fluorometric sensing of Al3+ ions with a large enhancement in the fluorescent intensity due to the restricted photoinduced electron transfer (PET) mechanism with a chelation-enhanced fluorescence (CHEF) effect. The AHB-Al3+ complex shows a remarkably low limit of detection at 0.498 nM. The binding mechanism has been proposed based on Job’s plot, 1H NMR titration, Fourier transform infrared (FT-IR), high-resolution mass spectrometry (HRMS), and density functional theory (DFT) studies. The chemosensor is reusable and reversible in the presence of ctDNA. The practical usability of the fluorosensor has been established by a test strip kit. Further, the therapeutic potential of AHB against Al3+ ion-induced tau protein toxicity has been tested in the eye of Alzheimer’s disease (AD) model of Drosophila via metal chelation therapy. AHB shows great therapeutic potential with 53.3% rescue in the eye phenotype. The in vivo interaction study of AHB with Al3+ in the gut tissue of Drosophila confirms its sensing efficiency in the biological environment. A detailed comparison table included evaluates the effectiveness of AHB. © 2023 American Chemical Society.
Graphene oxide-supported nickel(ii) complex as a reusable nano catalyst for the synthesis of bis(indolyl)methanes
(Royal Society of Chemistry, 2023) Gautam Kumar; Ananya Srivastava; Vinod P. Singh
A novel catalytic system of a nickel(ii) complex of (E)-N′-((2-amino-5-chlorophenyl)(phenyl)methylene)-2-hydroxy-benzohydrazide (APH) supported on graphene oxide (GO) has been prepared. Detailed characterization of the synthesized catalyst has been carried out using NMR, FTIR, HRMS, PXRD, Raman, SEM, TEM, EDX and XPS. Its catalytic efficiency has been explored for the synthesis of various bis(indolyl)methane derivatives. The optimized reaction conditions prove that the catalyst is highly efficient, performs under mild conditions and is required in a very small amount (2 wt%). A diversified library of bis(indolyl)methane derivatives containing various electron donating and withdrawing substituents has been developed in high to excellent yields. The catalyst is equally efficient towards heterocyclic aldehydes. Moreover, owing to the strong covalent interaction between the APH-Ni(ii) complex and GO, the catalyst shows outstanding recyclability for six subsequent cycles without any significant loss in activity. © 2023 The Royal Society of Chemistry.
Micronutrient and redox homeostasis contribute to Moringa oleifera-regulated drought tolerance in wheat
(Springer Science and Business Media B.V., 2023) Sahana Basu; Amlan A. Prabhakar; Surbhi Kumari; Aabha; Ravi Ranjan Kumar; Shashi Shekhar; Krishna Prakash; Jitendra P. Singh; Gyanendra P. Singh; Ram Prasad; Gautam Kumar
Global food security is being severely affected by the rapid increase in population and drastic climate change. Drought stress is the most important limiting factor for the sustainable production of several important crops, including wheat. The gradual temperature rise and reduced precipitations are likely to cause the frequent onset of droughts around the world. Therefore, alleviation of drought stress in crop plants has become an essential requirement to meet the increasing food demand. The present study explored the role of foliar application of Moringa leaf extract (MLE) in conferring drought tolerance in wheat during the anthesis stage. A wheat genotype of Indo-Gangetic Plains (HI1544) was exposed to drought stress during the anthesis of the spikes and simultaneously foliar sprayed with MLE for 10 days. The results showed the MLE treatment to improve the concentrations of macro- (K, Ca) and micronutrients (B, Cu, Fe, Mn, Zn, Si) in flag-leaves of wheat under non-stressed conditions. Application of MLE also maintained the flag-leaf nutritional contents under drought stress. The micro-nutrients, including Cu, Fe, Mn, and Zn being the co-factors of the enzymes also stimulated the antioxidant enzyme activities; eventually leading to a significant reduction in the reactive oxygen species and malondialdehyde accumulations under drought stress. Furthermore, micronutrients played a crucial role in osmotic adjustment and sustainable plant growth under drought stress. Overall, the study provided insights into the functional role of micronutrients in improving drought tolerance and also indicated the potential to commercialize MLE as an effective bio-stimulant for sustainable agriculture in drought-prone regions. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.
Plant growth promoting rhizobacterium Bacillus sp. BSE01 alleviates salt toxicity in chickpea (Cicer arietinum L.) by conserving ionic, osmotic, redox and hormonal homeostasis
(John Wiley and Sons Inc, 2023) Sahana Basu; Surbhi Kumari; Pritee Subhadarshini; Aniket Kumar Rishu; Shashi Shekhar; Gautam Kumar
Soil salinity leading to sodium toxicity is developing into a massive challenge for agricultural productivity globally, inducing osmotic, ionic, and redox imbalances in plants. Considering the predicted increase in salinization risk with the ongoing climate change, applying plant growth-promoting rhizobacteria (PGPR) is an environmentally safe method for augmenting plant salinity tolerance. The present study examined the role of halotolerant Bacillus sp. BSE01 as a promising biostimulant for improving salt stress endurance in chickpea. Application of PGPR significantly increased the plant height, relative water content, and chlorophyll content of chickpea under both non-stressed and salt stress conditions. The PGPR-mediated tolerance towards salt stress was accomplished by the modulation of hormonal signaling and conservation of cellular ionic, osmotic, redox homeostasis. With salinity stress, the PGPR-treated plants significantly increased the indole-3-acetic acid and gibberellic acid contents more than the non-treated plants. Furthermore, the PGPR-inoculated plants maintained lower 1-aminocyclopropane-1-carboxylic acid and abscisic acid contents under salt treatment. The PGPR-inoculated chickpea plants also exhibited a decreased NADPH oxidase activity with reduced production of reactive oxygen species compared to the non-inoculated plants. Additionally, PGPR treatment led to increased antioxidant enzyme activities in chickpea under saline conditions, facilitating the reactive nitrogen and oxygen species detoxification, thereby limiting the nitro-oxidative damage. Following salinity stress, enhanced K+/Na+ ratio and proline content were noted in the PGPR-inoculated chickpea plants. Therefore, Bacillus sp. BSE01, being an effective PGPR and salinity stress reducer, can further be considered to develop a bioinoculant for sustainable chickpea production under saline environments. © 2023 Scandinavian Plant Physiology Society.
Quinazoli-4-one ionic liquid as a fluorescent sensor for NH3 detection: Interaction with ctDNA, theoretical investigation and live cell bioimaging
(Elsevier B.V., 2023) Ananya Srivastava; Gautam Kumar; Prabhat Kumar; S. Srikrishna; Vinod P. Singh
A novel quinazoli-4-one based ionic liquid, 1-(3-aminopropyl)-3-methyl-4-oxo-3,4-dihydroquinazolin-1-ium bromide (QIL) for fluorometric determination of dissolved ammonia has been successfully synthesized and characterized by spectroscopic techniques such as 1H and 13C NMR, FTIR and HRMS spectrometry. In the proposed method, QIL is converted to a fluorescent derivative by the reaction with ammonia in aqueous medium. The excitation and emission wavelengths were 250 and 436 nm, respectively. Remarkably with the reaction time of >1 s, the binding constant and detection limit was found to be 6.43 × 108 M−1 and 0.73 × 10−8 M, respectively. QIL is found to be highly selective as no interference is observed from various cations, anions, organic molecules and amino acids. The sensing mechanism was further validated by the density functional theory studies. The fluorophore exhibited great sensing property in 3.0–14.0 pH range, hence, it can be employed in diverse matrices. In addition, the fluoro-sensor is highly reversible and reusable in the presence of ctDNA molecule. Moreover, a live-cell imaging study of QIL in Drosophila larval gut tissue has also been carried out to investigate the cell permeability of QIL and its efficiency for selective detection of NH3 in cellular micro environment. To show practical applicability of the fluoro-sensor, test strip kit has been constructed. A detailed comparison table has been shown to evaluate the efficiency of this method. © 2023 Elsevier B.V.
Reactive oxygen species and reactive nitrogen species induce lysigenous aerenchyma formation through programmed cell death in rice roots under submergence
(Elsevier B.V., 2020) Sahana Basu; Gautam Kumar; Nitu Kumari; Surbhi Kumari; Shashi Shekhar; Santosh Kumar; Ravi Rajwanshi
Nitric oxide (NO) plays a significant role in plants under different abiotic stress. However, the influence of NO and other reactive nitrogen species (RNS) in employing nitrosative stress in rice seedlings under submergence remains unexplored. Submergence also stimulates the development of lysigenous aerenchyma, facilitating oxygen supply to roots but the contribution of NO and RNS in aerenchyma formation under submergence is not known. Present study investigated the major components of the nitro-oxidative stress and their association with lysigenous aerenchyma development in the Sub1 near isogenic line of rice under submergence. Following submergence, Swarna showed increased NADPH oxidase (NOX) activity with excess reactive oxygen species (ROS) production in roots. Submergence also caused increased NO content and membrane lipid peroxidation in Swarna roots. Submergence-induced ROS and RNS accumulation in roots disturbed the redox homeostasis leading to the formation of lysigenous aerenchyma through programmed cell death (PCD). PCD was also accompanied by altered cytoplasmic streaming and DNA damage. In the present study Swarna Sub1 exhibited increased SOD, CAT, POX, APX, GR and GSNOR activity with subsequent detoxification of ROS and RNS; eventually decreasing the aerenchyma formation in root under submerged conditions. Overall, the study established ROS and RNS-mediated unique mechanism in lysigenous aerenchyma formation in rice roots under submergence. © 2020 Elsevier B.V.
Redox imbalance disrupts spikelet fertility in rice: A study under stage-specific and multi-stage drought in eastern Indo-Gangetic plain
(Elsevier B.V., 2023) Santosh Kumar; Sahana Basu; A.K. Choudhary; J.S. Mishra; Surajit Mondal; Shashi Shekhar; S.K. Dwivedi; Rakesh Kumar; Surbhi Kumari; Narayan Bhakta; Sanjeev Kumar; Ujjwal Kumar; Arvind Kumar; Gautam Kumar
To support the increasing food demand of the drought-prone eastern Indo-Gangetic plain (EIGP), we assessed the effects of natural drought stress on the individual (seedling stage drought; SSD, vegetative stage drought; VSD, reproductive stage drought; RSD) as well as the multiple growth stages (multi-stage drought; MSD) of twenty-four rice genotypes (n = 24) under field conditions for two consecutive rice growing seasons (2019–2020). High temperature and low rainfall during both the trial years exerted moderate to severe drought stress to the rice genotypes leading to average grain yield reduction of 43.5%, 28.9%, 59.3%, and 69.9% under SSD, VSD, RSD, and MSD conditions, respectively. The present study also revealed that drought stress caused enhanced accumulation of reactive oxygen species (ROS) in the spikelets of rice genotypes thereby, impeding the spikelet fertility. The promising rice genotypes showed an average decrease of 3.18%, 4.83%, 13.9%, and 13.06% in spikelet fertility under SSD, VSD, RSD, and MSD conditions, respectively. Identified promising rice genotypes, IR83929-B-B-291–2–1–1–2, IR93827–29–1–1–2 and IR84899-B-183–20–1–1–1 showed extreme drought tolerance and better maintained photosynthetic rate, stomatal conductance, relative water content, membrane stability index, and total chlorophyll content under drought conditions irrespective of growth stages. Following the study, drought tolerance in the tolerant rice genotypes was associated with increased antioxidant enzyme mediated efficacious ROS detoxification, which contributed in maintaining pollen viability and spikelet fertility. Overall, the study identified drought tolerant rice genotypes for EIGP and established a comprehensive understanding of the complexity and plasticity of the rice genotypes under stage-specific and cumulative drought stress. © 2022 Elsevier B.V.
Sequential submergence and drought induce yield loss in rice by affecting redox homeostasis and source-to-sink sugar transport
(Elsevier B.V., 2024) Santosh Kumar; Sahana Basu; A.K. Choudhary; Shashi Shekhar; J.S. Mishra; Sanjeev Kumar; Kumari Shubha; Rachana Dubey; Surajit Mondal; S.K. Dwivedi; N. Bhakta; Rakesh Kumar; Sujoy Sarkar; Srustidhar Dhamudia; Sunny Kumari; Anup Das; Arvind Kumar; Gautam Kumar
Rice cultivation in the rainfed ecosystems of the eastern Indo-Gangetic plain (EIGP) frequently comes across abrupt alternation of submergence and drought during the vegetative and reproductive stages, respectively, within one growing season, and this may be exaggerated with climate change. Therefore, development of combined submergence and drought tolerant rice genotypes might be a timely effort to meet the growing food demand. However, till date no study has been executed on the combination of submergence and drought stress in the field conditions of the EIGP. The present study elucidated the performance of near isogenic lines (NILs) of rice developed for the EIGP through marker assisted pyramiding of quantitative trait loci (QTL) associated with submergence (Sub1) and drought (qDTY1.1 + qDTY2.1 + qDTY3.1) in the background of the popular, high yielding Indo-Gangetic rice variety Swarna. This study included the screening of sixteen rice NILs along with the check varieties Swarna and Swarna Sub1 under cumulative submergence and drought for four consecutive rice growing years (2019–2022). Individual submergence or drought or cumulative stress caused 76, 47, and 85% respective loss in average productivity compared to that of the control conditions. However, rice NILs IR96321–558–563-B-2–1–1, IR96321–315–323-B-3–1–3, IR96321–315–294-B-1–1–1–1, and IR96321–558–209-B-6–1–1 showed outstanding cumulative stress tolerance with sustainable photosynthetic performance and membrane stability. Furthermore, these rice NILs exhibited effective reactive oxygen species scavenging mediated by enhanced antioxidant enzyme activities in source (flag-leaf) and sink (anther) tissues that contributed to conserving the source-to-sink mobilization, leading to improved pollen viability and spikelet fertility under sequential stress conditions. The study identified combined submergence-drought tolerant rice NILs along with an optimum yield level to support global food security and also represented a model crop system to establish mechanisms of multi-stress tolerance in plants. © 2024 Elsevier B.V.
Thiazole-Based Silver Ion Sensor for Sequential Colorimetric Visualization of Epinephrine in the Brain Tissues of an Alzheimer’s Disease Model of Mouse
(American Chemical Society, 2024) Ananya Srivastava; Gautam Kumar; Prabhat Kumar; S. Srikrishna; Pranjal Chandra; Vinod P. Singh
A thiazole-based probe, N′-((2-aminothiazol-5-yl)methylene)benzohydrazide (TBH), has been efficiently synthesized and characterized for the selective and sensitive detection of the neurotransmitter epinephrine (EP). The sensing strategy is based on the use of TBH for sequential colorimetric sensing of Ag+ and EP via in situ formation of Ag nanoparticles (Ag NPs) from the TBH-Ag+ complex. The generated Ag NPs lead to a bathochromic shift in absorption maximum and a change in color of the solution from light brown to reddish brown. TBH-Ag+ shows remarkable selectivity toward EP versus other drugs, common cations, anions, and some biomolecules. Moreover, TBH-Ag+ has a low detection limit for EP at 1.2 nM. The coordination of TBH-Ag+ has been proposed based on Job’s plot, Fourier transform infrared spectroscopy (FT-IR), high-resolution mass spectrometry (HRMS), 1H NMR titration, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray analysis (EDAX), and density functional theory (DFT) studies. The composition and morphology of the generated Ag NPs have been analyzed by XPS, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The proposed sensing mechanism for EP has been supported by XPS of Ag after the reaction. Further, the sensitivity of TBH-Ag+ toward EP in brain tissues of an Alzheimer’s disease model of mouse has been evaluated. A thorough comparison was done for evaluation of the proposed method. © 2024 American Chemical Society