Browsing by Author "Vikas Kumar Singh"

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A Facile and Simple Strategy for the Synthesis of Label Free Carbon Quantum Dots from the latex of Euphorbia milii and Its Peroxidase-Mimic Activity for the Naked Eye Detection of Glutathione in a Human Blood Serum
(American Chemical Society, 2019) Daraksha Bano; Vijay Kumar; Vikas Kumar Singh; Subhash Chandra; Devendra Kumar Singh; Pradeep Kumar Yadav; Mahe Talat; Syed Hadi Hasan
Herein a green synthetic route has been developed for the synthesis of water-soluble CQDs by facile single-step hydrothermal treatment of latexes of E. milii plant for the first time. This methodology is zero-cost; uses ultrapure water as a green solvent; does not use strong concentrated acid; and avoids the use of post surface passivating agents. The as-prepared CQDs exhibited excellent optical properties, including high QY up to 39.2%, resistance to high salt strength, and long time photostability. Furthermore, the as-prepared CQDs served as an intrinsic peroxidase-mimic activity to catalyze the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) associated with H 2 O 2 , which resulted into a blue-colored reaction with a characteristic absorbance peak at 652 nm. Afterward, the proposed TMB-based oxidation system act as a probe for the detection of GSH and offers the high selectivity relative to the different amino acids and various other interfering agents which can be easily seen with naked eye. The limit of detection (LOD) was found to be 5.3 nM in a linear range 0.02 to 0.1 μM of GSH concentration which showed to be superior under the optimal condition as compared with another probe. To demonstrate the practical feasibility for the GSH detection, the present system was successfully applied on human blood serums with good recovery. © 2018 American Chemical Society.
Bright-blue-emission nitrogen and phosphorus-doped carbon quantum dots as a promising nanoprobe for detection of Cr(vi) and ascorbic acid in pure aqueous solution and in living cells
(Royal Society of Chemistry, 2018) Vikas Kumar Singh; Virendra Singh; Pradeep Kumar Yadav; Subhash Chandra; Daraksha Bano; Vijay Kumar; Biplob Koch; Mahe Talat; Syed Hadi Hasan
Highly fluorescent nitrogen and phosphorus-doped carbon quantum dots (N,P-CQDs) were synthesized via a one-step hydrothermal method and fully characterized via various techniques such as TEM, DLS, FT-IR, P-XRD and XPS analysis. The as-synthesized N,P-CQDs showed excellent optical properties and exhibited bright blue colour under UV-light with CIE coordinate (0.20, 0.22) along with a high quantum yield of 73%, due to which they could act as on-off fluorescent nanoprobes for the selective and sensitive detection of highly toxic Cr(vi) below its permissible limit via the inner filter effect (IFE) and static quenching mechanism. In addition, Cr(vi) could be reduced to lower valent chromium species. Therefore, the N,P-CQDs + Cr(vi) system further acted as a selective off-on sensor for reductant ascorbic acid (AA) because it reduced Cr(vi) to Cr(iii) species, resulting in the elimination of IFE and recovery of fluorescence of N,P-CQDs. Notably, this system possesses excellent biocompatibility and negligible cytotoxicity; therefore, it can be potentially applied for fluorescence imaging of intracellular Cr(vi) and ascorbic acid (AA) in living cells and complex biological systems. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
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, 2025) Vikky Kumar Mahto; Vikas Kumar Singh; Vipendra Kumar Singh; Avinash K. Singh; Savita S. 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.
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.
Green Synthesis of Fluorescent Carbon Quantum Dots from Azadirachta indica Leaves and Their Peroxidase-Mimetic Activity for the Detection of H 2 O 2 and Ascorbic Acid in Common Fresh Fruits
(American Chemical Society, 2019) Pradeep Kumar Yadav; Vikas Kumar Singh; Subhash Chandra; Daraksha Bano; Vijay Kumar; Mahe Talat; Syed Hadi Hasan
In the present study, an ecofriendly and zero-cost approach has been demonstrated for the preparation of carbon quantum dots by one-pot hydrothermal treatment of leaf extracts of neem (Azadirachta indica). The as-synthesized neem carbon quantum dots (N-CQDs) exhibited high fluorescent quantum yields (QYs) up to 27.2%. Moreover, N-CQDs also act with a peroxidase-like-mimetic activity toward the oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in association with hydrogen peroxide (H 2 O 2 ). Further, the kinetics of peroxidase-like catalytic activity follows the Michaelis-Menten and ping-pong pathway. In addition, the H 2 O 2 sensitive TMB oxidation motivated the colorimetric detection of H 2 O 2 which showed linearity from 0.1 to 0.5 mmol/L with a detection limit (LOD) of 0.035 mmol/L. Furthermore, the blue colors of oxidized TMB (ox-TMB) were selectively reduced in native TMB with ascorbic acid (AA) without any interference of other reducing agents. The linear range of AA detection was lying between 5 and 40 μM with a LOD up to 1.773 μM. The practicability assay of the proposed sensing system toward the detection of AA was also investigated in real sample analysis such as common fruits which showed good sensitivity to the presence of AA. Therefore, this convenient, ecofriendly, and cost-effective peroxidase-based sensing system opens a new platform for analysis of AA in real samples and in complex biological systems. Copyright © 2018 American Chemical Society.
Green synthesis of gold nanoparticles from Dunaliella salina, its characterization and in vitro anticancer activity on breast cancer cell line
(Editions de Sante, 2019) Ankit Kumar Singh; Ratnakar Tiwari; Vikas Kumar Singh; Prabhakar Singh; Sk Riyazat Khadim; Urmilesh Singh; Laxmi; Vikas Srivastava; S.H. Hasan; R.K. Asthana
An ecofriendly and efficient method (photoinduced) has been used for green synthesis of stable gold nanoparticles (AuNPs) using aqueous extract as a reducing and stabilizing agent, derived from halotolerant microalga Dunaliella salina. Synthesis of AuNPs was confirmed by UV–Vis spectroscopy showing sharp SPR band at 560 nm after 30 min exposure of sunlight. The synthesis was optimized further as exposure(75min) to sunlight, aqueous extract of Dunaliella (AED) inoculum dose(30%) and HAuCl 4 .xH 2 O (1 mM). The presence of nearly spherical shape of AuNPs with average size of 22.4 nm and crystalline nature were confirmed by TEM, SAED and XRD analysis. The XPS analysis of AuNPs showed presence of two individual peaks at 85.17 and 88.94eV that attributed to Au 4f7/2 and Au 4f5/2 respectively. Phycochemical analysis of AED demonstrated presence of phenolics, flavonoids, tannin and proteins. AED when subjected to SDS-PAGE showed protein bands of 92 and 66 KDa. AuNPs were tested for anticancer activity on MCF7 (cancer) and MCF 10A (normal) cell lines, keeping commercial drug cisplatin as positive control. AuNPs selectively killed cancer cells and were not detrimental to the normal cell line whereas cisplatin killed normal cells also at 48 h exposure, therefore, such AuNPs may be used as an anticancer agent. © 2019 Elsevier B.V.
Hidden in Plain Sight: The Unrecognized Contribution of the Survey of India in the Documentation of Ancient Settlements in Pakistan and India
(Taylor and Francis Ltd., 2025) Cameron A. Petrie; Junaid Abdul Jabbar; Abhayan; G. S; Aftab Alam; Iban Berganzo-Besga; Rosie Campbell; Francesc C. Conesa; Moazzam Durrani; Arnau Garcia-Molsosa; Petrus Johannes Gerrits; Adam S. Green; Lily M. Green; Jonas Gregorio De Souza; Muhammad Hameed; Afifa Khan; Marco Madella; M. Waqar Mushtaq; Hector A. Orengo; V. N. Prabhakar; S. V. Rajesh; David I. Redhouse; Rebecca C. Roberts; Mou Sarmah; Abdul Samad; Ravindra Nath Singh; Vikas Kumar Singh; Maria Suarez Moreno; Jack A. Tomaney; Azadeh Vafadari; Vaneshree Vidyarthi
The earliest documentation of hundreds of ancient settlements in South Asia, including some of the most famous and significant sites, lies in largely unacknowledged subaltern hands. Operating during the British colonial period, teams employed by the Survey of India systematically mapped the colonial dominions and produced high-quality maps that depicted topography and land use across vast areas. Systematic analysis of these map sheets combined with ground-truthing is demonstrating that these teams documented thousands of mound features, and a significant number of these are (or sadly in many cases were) archaeological sites. Members of the original survey teams were for the most part not in a position to contribute their thoughts to the historical narrative, but the legacy of what they documented has long been hidden in plain sight. The collaborative Mapping Archaeological Heritage in South Asia (MAHSA) project is systematically documenting this archaeological heritage. Its work is demonstrating that the teams carrying out the Survey of India topographic surveys incidentally conducted the first systematic survey of archaeological sites in South Asia. This was potentially the world’s most extensive (albeit incidental) archaeological survey. © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Hoofprints in the yard: The discovery of bovid, caprid and (large) feline/canid tracks in an external courtyard from the early Iron Age of Tokwa, India
(Elsevier Ltd, 2025) Jennifer Bates; Vikas Kumar Singh; Ravindra Nath Singh; Manisha Singh; Brij Mohan; Sudarshan Chakradhari; Matthew Conte; Olzbayar Gankhuyag; Nathaniel James; Rakesh Jollu; Snigdha Konar; S. Dasaratha Kumar; Arun K. Pandey; Kim Pangyu; Abhay P. Singh; Anisha Singh; Sunil K. Singh; Urvashi Singh
Humans and animals have co-existed throughout our evolution, but evidence for this often comes in the form of death assemblages – animal bones. Evidence of the lived experience of animals in human spaces instead often has to come from secondary sources like stress marks on bone, imagery, artefacts and texts. In this paper we report evidence for animals exploring human habitation spaces in the form of hoof and paw prints left in wet plaster floors at the early Iron Age site of Tokwa, India. The tracks come from three separate animal groups – bovid, caprid and large feline/canid – and show presence at different moments in floor use through their presence in different plaster layers. This repeated use of a human habitation space, specifically outside courtyards, shows animals freely roaming through the area, and highlights not only biodiversity hidden from the site's zooarchaeological record, but also the intersection of multi-species lived experiences on a day-to-day basis that would otherwise not be visible over the millennia. © 2025
Multivariate stability analysis to select elite rice (Oryza sativa L.) genotypes for grain yield, zinc and Iron
(Nature Research, 2025) Akansha K. Singh; Dhirendra Kumar Singh; Shravan Kumar Singh; Vikas Kumar Singh; Arvind Kumar
The present study was conducted to evaluate 30 rice genotypes at three different locations in eastern Uttar Pradesh during the Wet- 2020–21 and determine the impact of GEI on grain yield (tha-1), days to 50% flowering, grain Fe content (PPM), and grain Zn content (PPM). The study also aimed to identify the genotypes that displayed the best performance according to the multi-trait stability index (MTSI), multi-trait genotype-ideotype distance index (MGIDI), and factor analysis and ideotype-design (FAI-BLUP) index. AMMI analysis demonstrated significant variation for environment (E), genotype (G), and genotype-by-environment interaction (GEI) (P < 0.01) for all the studied traits. The AMMI1 biplot showed that PC1 explained the majority of the variation for GY (77.6%), DTF (90.5%), Fe (73.5%), and Zn (86.8%), helping to identify stable and high-performing genotypes. AMMI2 biplot further resolved complex GEI patterns, highlighting genotypes with specific adaptability to individual environments. The GGE biplot revealed clear “which-won-where” patterns for GY, DTF, Fe, and Zn, explaining 94.37%, 99.71%, 83.49%, and 96.93% of GEI variation, respectively. BLUP analysis using a linear mixed model revealed significant GEI effects for GY, DTF, Fe, and Zn across 30 rice genotypes in three environments. Low heritability was observed for Fe (28.2%) and moderate for GY (54.4%) and Zn (56.4%), while DTF showed high heritability with strong genotypic accuracy. Genotype G7 was identified as stable, early, high-yielding, and rich in Fe based on HMGV, RPGV, and HMRPGV indices. The MTSI, MGIDI and FAI-BLUP analysis revealed that BHU-SKS-1 (G15) and IR105696 -1–2-3–1-1–1 -B (G9) were the most stable and best mean performer for high grain yield and high grain Fe & Zn content, while IR 108,195–3-1–1-2 (G7) was the most stable and best mean performer for high grain yield and high grain Fe content with early flowering. © The Author(s) 2025.
Mustard seeds derived fluorescent carbon quantum dots and their peroxidase-like activity for colorimetric detection of H 2 O 2 and ascorbic acid in a real sample
(Elsevier B.V., 2019) Subhash Chandra; Vikas Kumar Singh; Pradeep Kumar Yadav; Daraksha Bano; Vijay Kumar; Vinay Kumar Pandey; Mahe Talat; Syed Hadi Hasan
Herein, we were synthesized fluorescent carbon quantum dots via facile one-step hydrothermal treatment of mustard seeds (M-CQDs). It showed excellent optical property with fluorescent quantum yield 4.6%. The as-prepared M-CQDs exhibited peroxidase-like mimetic activity and catalyzed the oxidation of chromogenic substrate 3,3‘,5,5‘-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue color reaction mixture with the prominent peak at 652 nm. Furthermore, the peroxidase-like catalytic performance of M-CQDs followed the steady-state kinetics behavior and exhibited similar catalytic activity as that of natural enzyme Horseradish peroxidase (HRP). In addition to this, the double reciprocal plot showed a parallel line which suggested the occurrence of Ping-Pong type of mechanism. The H 2 O 2 dependent oxidation of TMB was helpful for the colorimetric detection of H 2 O 2 in the linear range of 0.02–0.20 mM with the limit of detection (LOD) of 0.015 mM. Interestingly, the oxidized TMB (ox-TMB) was further reduced to native TMB by the reducing agent ascorbic acid. Hence M-CQDs showed its potential towards the selective and sensitive detection of ascorbic acid in the linear range of 10–70 μM having a correlation coefficient of 0.998 with LOD of 3.26 μM. The practical feasibility of the proposed detection method of AA was also investigated in common fresh fruits. © 2018 Elsevier B.V.
Nitrogen doped fluorescent carbon quantum dots for on-off-on detection of Hg2+ and glutathione in aqueous medium: Live cell imaging and IMPLICATION logic gate operation
(Elsevier B.V., 2019) Vikas Kumar Singh; Virendra Singh; Pradeep Kumar Yadav; Subhash Chandra; Daraksha Bano; Biplob Koch; Mahe Talat; Syed Hadi Hasan
The present work describes the synthesis of N-CQDs via one step hydrothermal methods. The synthesized N-CQDs was fully characterized by TEM, P-XRD, FT-IR, XPS and Zeta sizer. It exhibited excitation independent emission behaviour with fluorescent quantum yield of 41% respect to quinine sulphate standard. The excellent optical properties of N-CQDs made it fluorescent probe for turn off detection of toxic heavy metal ion Hg2+ with good selectivity and sensitivity. The limit of detection was found to be 0.08 μM with correlation coefficient (R2 = 0.992). After addition of various reducing agent such as amino acid, EDTA and GSH in the quenched solution of N-CQDs + Hg2+, the fluorescence property was selectively recovered in the presence of GSH and hence the quenched solution further acts as selective turn on sensing of GSH up to lower limit of 2.0 μM with correlation coefficient (R2 = 0.996). The on-off-on sensing behaviour of N-CQDs was utilized for the implication of logic gate in absence and presence of Hg2+ and GSH to construct the molecular switches. The MTT assay of N-CQDs was performed on MCF-7 cancer cell line to check their applicability in biological system and the result showed negligible cytotoxicity and good permeability. The cell imaging on MCF-7 cells visualized in dichromic region (blue and green). Therefore, it could be smart material for sensing of heavy toxic metal as well as cell imaging application. © 2019 Elsevier B.V.
Nitrogen/sulfur-co-doped carbon quantum dots: a biocompatible material for the selective detection of picric acid in aqueous solution and living cells
(Springer, 2020) Subhash Chandra; Daraksha Bano; Priyadarshika Pradhan; Vikas Kumar Singh; Pradeep Kumar Yadav; Devanjan Sinha; Syed Hadi Hasan
Here, a fast and eco-friendly one-pot hydrothermal technique is utilized for the synthesis of nitrogen/sulfur-co-doped fluorescent carbon quantum dots (NS-CQDs) from a simple precursor of citric acid (CA) and thiosemicarbazide (TSC). The obtained NS-CQDs exhibited strong blue emission under UV light, with fluorescence quantum yield (QY) of ~37.8%. The Commission internationale de l’eclairage (CIE) coordinates originated at (0.15, 0.07), which confirmed the blue fluorescence of the synthesized NS-CQDs. Interestingly, the prepared NS-CQDs were successfully used as a selective nanoprobe for the monitoring of environmentally hazardous explosive picric acid (PA) in different nitro- and non-nitro-aromatic derivatives of PA. The mechanism of the NS-CQDs was also explored, and was posited to occur via the fluorescence resonance electron transfer (FRET) process and non-fluorescent complex formation. Importantly, this system possesses excellent biocompatibility and low cytotoxicity in HeLa cervical cancer cells; hence, it can potentially be used for PA detection in analytical, environmental, and pathological applications. Furthermore, the practical applicability of the proposed sensing system to pond water demonstrated the feasibility of our system along with good recovery. [Figure not available: see fulltext.] © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
One pot hydrothermal synthesis of fluorescent NP-carbon dots derived from Dunaliella salina biomass and its application in on-off sensing of Hg (II), Cr (VI) and live cell imaging
(Elsevier B.V., 2019) Ankit Kumar Singh; Vikas Kumar Singh; Mamata Singh; Prabhakar Singh; Sk. Riyazat Khadim; Urmilesh Singh; Biplob Koch; S.H. Hasan; R.K. Asthana
The impact of hazardous chemicals and toxic metal ions in the environment played havoc to the ecosystem. In the present work green chemistry approach was applied for one-step hydrothermal synthesis of nitrogen, phosphorus dual doped carbon dots, utilizing green precursor i.e, biomass of halophilic microalgae Dunaliella salina (algal derived nitrogen phosphorous carbon dots i.e A-NPCDs). Synthesized A-NPCDs were characterized through TEM, FT-IR, P-XRD, DLS and XPS. It showed appreciable optical properties with significant fluorescence quantum yield (8%)and exhibited blue color under UV – light (λ ex = 365 nm). A-NPCDs acted as fluorescent turn off sensor for toxic metal ion such as Hg (II) and Cr (VI) with good selectivity and sensitivity. Interestingly, ANPCDs detected Cr (VI) up to 0.018μM which was below the permissible level of Cr (VI) in drinking water. Such sensing resulted because of combination of inner filter effect and dynamic quenching mechanism. Moreover, it also showed good selectivity (0.018μM) for Hg (II) via dynamic quenching mechanism. MTT assay of A-NPCDs on HEK-293 cell line showed biocompatibility with negligible cytotoxicity. Therefore, these were successfully employed for live cell imaging and intracellular detection of Hg (II) and Cr (VI) in HEK-293 cell line. Thus, green synthesized A-NPCDs may be a good alternative for chemically derived CDs in intracellular detection of Hg (II) and Cr (VI) of a complex biological environment. © 2019
Peroxidase mimetic activity of fluorescent NS-carbon quantum dots and their application in colorimetric detection of H2O2 and glutathione in human blood serum
(Royal Society of Chemistry, 2018) Vikas Kumar Singh; Pradeep Kumar Yadav; Subhash Chandra; Daraksha Bano; Mahe Talat; Syed Hadi Hasan
Interest is growing in the development of artificial enzymes to overcome the drawbacks of natural enzymes. Herein, we have synthesized nitrogen-sulphur dual-doped carbon quantum dots (NS-CQDs) via a one-step hydrothermal method; the NS-CQDs possess excellent optical properties and a high fluorescent quantum yield (46%). Significantly, the NS-CQDs exhibited peroxidase mimetic enzyme activity without support from metals or polymeric materials and efficiently catalyzed the oxidation of peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue solution with an absorption maximum at 652 nm. Mechanistic studies suggest that the small size and high electron density of NS-CQDs play vital roles and accelerate the reduction of H2O2 to generate OH radical, which facilitates the oxidation of TMB. The catalytic activity is based on Michaelis-Menten kinetic behavior, and steady state kinetic analysis suggests that the NS-CQDs exhibit a higher affinity for H2O2 than TMB, similar to the natural enzyme horseradish peroxidase (HRP). Moreover, the catalytic pathway follows a ping-pong mechanism. Therefore, these findings offer a worthy platform for colorimetric detection of H2O2 in a linear range of 0.02 mM to 0.1 mM with a limit of detection of 0.004 mM. Interestingly, the blue colour of oxidized TMB showed excellent selectivity over non-thiolate biological molecules, especially amino acids, and glutathione can be detected up to 0.07 μM via colorimetric and fluorimetric assays. Additionally, this system showed excellent recovery (96.0-108.3%) of GSH from human blood serum. Thus, the proposed sensing system is simple, convenient, and straightforward and can be potentially applied for real time monitoring of H2O2 and glutathione in biological samples. © 2018 The Royal Society of Chemistry.
Population structure and genetic diversity in popular rice varieties of India as evidenced from SSR analysis
(2012) Priti Upadhyay; C.N. Neeraja; C. Kole; Vikas Kumar Singh
We report here on the phylogenetic analysis, population substructure, and identification of molecular tags of 25 popular rice varieties and four landraces from different ecological belts of India employing a set of 52 simple sequence repeat (SSR) markers. Genetic analysis using the SSR markers categorized the genotypes into two major clusters, distributed according to their pedigree. Population structure analysis suggested that the optimum number of subpopulations was three (K = 3) in the popular varieties and landraces. At K = 5 the allelic distribution was much more similar to the phylogenetic dendrogram. The molecular diversity and population structure analysis indicated that there is not much variation among the popular rice cultivars of India. The study has identified SSR markers producing unique alleles, which should aid in the precise identification, maintenance, and genetic purity analysis of rice varieties. © Springer Science+Business Media, LLC 2012.
Pyrene-fluorescein-based colour-tunable AIE-active hybrid fluorophore material for potential live cell imaging applications
(Royal Society of Chemistry, 2017) Vikas Kumar Singh; Ritika Prasad; Biplob Koch; Syed Hadi Hasan; Mrigendra Dubey
A novel hybrid fluorophore (FHPY) has been synthesized based on a condensation reaction of two standard fluorescent hydrophobic-hydrophilic molecules, viz. pyrene and fluorescein, with an objective to tune the aggregation-induced emission (AIE) along with the morphology. Owing to the distinct photophysical properties of pyrene and fluorescein, the hybrid FHPY dramatically exhibits a fluorescence change from colourless to yellow-green via a blue colour upon varying the volume fraction of water (poor solvent) in methanol (good solvent). FHPY has exhibited not only AIE, but also an outstanding quantum yield (ΦF) of 97% at a 70% water fraction in methanol (70-:-30, v/v). We attribute the reason behind the tuning of the AIE and quantum yield to the opening of the lactam ring of fluorescein as well as to the amassing of hydrophobic pyrene at a certain water fraction. The mechanism involved in the AIE has been well supported by detailed UV-vis, fluorescence, lifetime, SEM, AFM, DFT, PXRD and 1H NMR experiments. In addition, FHPY serves as a good candidate for the live cell imaging of HeLa cells. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2017.
QTL mapping reveals different set of candidate genes governing stable and location specific QTLs enhancing zinc and iron content in rice
(Springer Science and Business Media B.V., 2024) Sonali Vijay Habde; Shravan Kumar Singh; Dhirendra Kumar Singh; Arun Kumar Singh; Rameswar Prasad Sah; Mounika Korada; Amrutlal R. Khaire; Prasanta Kumar Majhi; Uma Maheshwar Singh; Vikas Kumar Singh; Arvind Kumar
Rice is a cornerstone of global food security. Addressing contemporary dual challenge of global food and nutritional security, this study focuses on identification of genomic regions/QTLs that control uptake and translocation of micronutrients (Zn and Fe) in rice. Using mapping population derived from a cross between URG 30 (Zn 32.2 ppm and Fe 15.3 ppm) and Rajendra Kasturi (Zn 19.2 ppm and Fe 9.5 ppm), evaluated at three locations, we identified 8 QTLs each for grain Zn and Fe content distributed across 8 chromosomes. Notably 3 major QTLs for grain Zn content (chromosomes 1, 5 and 6) and 1 major QTL for grain Fe content (chromosome 3) were identified with phenotypic variance (PV) ranging from 10.7 to 15.19% for Zn and 12.10% for Fe. Two stable QTLs for grain Zn content (PV 5.89–8.98% and 3.18–13.62%) and one for Fe content (PV 1.84–7.59%) were consistently identified at two locations. Seven transgressive segregants for yield and Zn content are identified at two locations. Correlation analysis uncovered significant positive associations between grain Zn and Fe content. We also interpreted the functional role of 24 candidate genes including key candidates OsZIP1, OsSPR1, OsZIP2, OsPEZ1, OsZIP6, OsNAS1, OsNAS2, OsYSL3 underlying stable and location specific QTLs in the context of mineral uptake strategies utilized by rice. The research supports marker assisted breeding efforts towards substantial nutritional enhancement in rice grain. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.
Socio-economic profile of beneficiaries of Swarna Jayanti Gram Swarozgar Yojana (SGSY) of Amaniganj block of Faizabad district (U. P.)
(Agri Bio Research Publishers, 2016) Rahul Kumar Singh; R.K. Doharey; Abhishek Pratap Singh; N.K. Tiwari; Chandan Kumar Singh; Vikas Kumar Singh
A study was conducted in Amaniganj block of Faizabad district of Uttar Pradesh to know the socio-economic profile of beneficiaries of Swarna Jayanti Gram Swarozgar Yojana (SGSY) during the year 2013. One hundred farmers were selected randomly from the list of five purposely selected villages i. e. Raipatti, Manjhanpur Manudeeh, Satemau and Taldholi. The relevant variables were selected after reviewing the literatures available and the works done in the field prior to the present investigation. Age, caste, family size, family type, land holding capacity, occupation, social participation, material possession, scientific orientation, economic motivation, risk orientation and value orientation were considered as socio-economic indicators. A well structured and pre-tested interview schedule was used for data collection through personal interview method. The data were analyzed by using percentage, mean and standard deviation. The findings of the study revealed that majority of the respondents were middle aged (66%), literate (82 %) and belonged to general caste (40%). Majority of the respondents belonged to nuclear family (52%), medium sized family (69%) with mixed housing pattern (56%) and having marginal land holding (72%); most of them adopted agriculture as a main occupation (15.00%) and participated in one organization (41%). Majority of the respondents (70%) were observed to be in the medium category (17-53 scores) of materials possession and having medium level of economic motivation (67%); majority of the respondents were having medium level of scientific orientation (66%), medium level of risk orientation (62%) and had medium level of value orientation (59%).
Speed breeding 3.0: mainstreaming light-driven plant breeding for sustainable genetic gains
(Elsevier Ltd, 2025) Pramod Gorakhanath Kabade; S. Veeresh J. Kumar; Ajay Kohli; Uma Maheshwar Singh; Pallavi Sinha; Vikas Kumar Singh
Advances in photobiological tools are revolutionizing plant breeding by enabling precise control of light parameters, addressing yield stagnation, and mitigating climate challenges. Full-spectrum light-emitting diodes (LEDs) and optimized light protocols have significantly reduced breeding cycles. This review highlights light-driven strategies that are accessible and practical for plant breeders worldwide including the role of light spectrum, intensity, and photoperiod in acceleration of plant growth in both short- and long-day crops. Speed breeding 3.0, with tailored rapid generation advancement (RGA) protocols designed for diverse crop populations, has the potential to significantly sustain genetic gains in a more efficient and targeted manner. These innovative approaches hold the potential to transform global agriculture and secure food systems in the face of rising populations and environmental uncertainties. © 2025 Elsevier Ltd
SpeedFlower: a comprehensive speed breeding protocol for indica and japonica rice
(John Wiley and Sons Inc, 2024) Pramod Gorakhanath Kabade; Shilpi Dixit; Uma Maheshwar Singh; Shamshad Alam; Sankalp Bhosale; Sanjay Kumar; Shravan Kumar Singh; Jyothi Badri; Nadimpalli Rama Gopala Varma; Sanjay Chetia; Rakesh Singh; Sharat Kumar Pradhan; Shubha Banerjee; Rupesh Deshmukh; Suresh Prasad Singh; Sanjay Kalia; Tilak Raj Sharma; Sudhanshu Singh; Hans Bhardwaj; Ajay Kohli; Arvind Kumar; Pallavi Sinha; Vikas Kumar Singh
To increase rice yields and feed billions of people, it is essential to enhance genetic gains. However, the development of new varieties is hindered by longer generation times and seasonal constraints. To address these limitations, a speed breeding facility has been established and a robust speed breeding protocol, SpeedFlower is developed that allows growing 4–5 generations of indica and/or japonica rice in a year. Our findings reveal that a high red-to-blue (2R > 1B) spectrum ratio, followed by green, yellow and far-red (FR) light, along with a 24-h long day (LD) photoperiod for the initial 15 days of the vegetative phase, facilitated early flowering. This is further enhanced by 10-h short day (SD) photoperiod in the later stage and day and night temperatures of 32/30 °C, along with 65% humidity facilitated early flowering ranging from 52 to 60 days at high light intensity (800 μmol m−2 s−1). Additionally, the use of prematurely harvested seeds and gibberellic acid treatment reduced the maturity duration by 50%. Further, SpeedFlower was validated on a diverse subset of 198 rice accessions from 3K RGP panel encompassing all 12 distinct groups of Oryza sativa L. classes. Our results confirmed that using SpeedFlower one generation can be achieved within 58–71 days resulting in 5.1–6.3 generations per year across the 12 sub-groups. This breakthrough enables us to enhance genetic gain, which could feed half of the world's population dependent on rice. © 2023 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.