Browsing by Author "Ashutosh"

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A comparative study of a class of direct estimators for domain mean with a direct ratio estimator for domain mean using auxiliary character
(Glowny Urzad Statystyczny, 2021) Brij Behari Khare; Ashutosh; Piyush Kant Rai
Estimation techniques for a domain parameter play a very significant role in the theory of sample surveys. In the recent years many advanced methodologies have been developed for domain estimation. In particular, direct and synthetic estimators are applied for the estimation of domain mean in the government and private sectors under certain assumptions as to the size of the samples relating to particular domains. The findings demonstrate that the direct estimator fails to perform more efficiently as compared to the synthetic estimator when reliable units are not directly accessible in the studied domains. Moreover, due to the fact that small units belong to the sample of the studied domain, the direct estimator produces an unacceptably large standard error. In contrast, if a sufficient number of units are available in the studied domain, the direct estimator produces effective results. This paper presents the theoretical aspects of the proposed class of direct estimators for domain mean with the use of a single auxiliary character, compared with an existing direct ratio estimator for domain mean (given in section 3.2). In addition, an empirical study has been provided to support the validity of the proposed estimators. The findings prove that the proposed estimators outperform the direct ratio estimator for domain mean using a single auxiliary character in the case of two studied populations and their analysed domains considered from Sarndal et al. (1992). © 2021 Glowny Urzad Statystyczny. All rights reserved.
A Comparative Study on Calibration Approach Based Estimators for Domain Estimation Utilizing Power Function: Revisited
(Springer Science and Business Media Deutschland GmbH, 2023) Ashutosh; Piyush Kant Rai; Ajeet Kumar Singh
The calibration approach based estimators of the domain mean have growing demand during past couple of decades. Estimation of domains is another challenging task for surveyors and several efforts have been made to produce the reliable estimators for this purpose. Prominently the power function based estimators in the sample surveys are having dual advantages for the selection and their application to produce an improved estimation at any stage in the terms of efficiency without much complexity. In the domain estimation utilization of the power function in the development of calibration based estimators are also very promising and provide considerable results. A simulation study has examined for the comparison of several calibration estimators along with the proposed estimator in terms of the absolute relative bias and simulated relative standard error. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Biofortifkation: A strategy to remove malnutrition and achieve sustainable development goals
(Nova Science Publishers, Inc., 2022) Prashant Singh; Ashutosh; Monu Kumar; Vinod Kumar Mishra; Neelam Atri
Biofortification is the process of breeding crops to increase their nutrient content, including micronutrient content (Zn, Fe and vitamins) and a strategy to achieve different United Nations - Sustainable Development Goals. Biofortification aims to boost the nutritional value of crops during their growth rather than after they've been processed into foods. Biofortification is a new field of study based on varietal crop trials conducted over the last decade with staple food crops that have been biofortified using traditional plant breeding methods in their respective regional staple crops, such as wheat and rice in South Asia, cassava in Africa, wheat and maize in Latin America, and so on. Biofortification of staple food crops is a cost-effective and long-term solution. Once a variety with a high content of an essential nutrient is developed, it can be maintained indefinitely. The elemental composition of a sample can be identified and quantified using X-ray spectra. Use X-Ray Fluorescence Technology (XRF) to screen for Zn/Fe in various staple crop germplasm around the world. According to the findings of the trials, biofortified food crops have a positive impact on nutritional and functional health outcomes. Additional implementation research will be required to ensure that the beneficial impact of this intervention is maximized and that scaling up is smooth to make biofortification a long-term public health intervention. © 2022 Nova Science Publishers, Inc..
Characterization of natural antimony resistance in Leishmania donovani isolates
(American Society of Tropical Medicine and Hygiene, 2007) Mukul K. Mittal; Smita Rai; Ashutosh; Ravinder; Suman Gupta; Shyam Sundar; Neena Goyal
Clinical resistance to pentavalent antimonial compounds has long been recognized as a major problem in the treatment of visceral leishmaniasis in India. However, mechanisms of natural resistance are unclear. In this study, we observed that Leishmania donovani clinical isolates not responsive to sodium stibogluconate showed resistance to antimony treatment in both in vitro and in vivo laboratory conditions. The resistant isolates have increased levels of intracellular thiols. This increase in thiol levels was not mediated by the amplification of γ-glutamylcysteine synthetase, but was accompanied by amplification of trypanothione reductase and an intracellular ATP-binding cassette transporter gene MRPA. The resistance of parasites to antimony could be reversed by the glutathione biosynthesis-specific inhibitor, buthionine sulfoximine, which resulted in increased drug susceptibility. These results suggest the possible role of thiols and MRPA in antimony resistance in field isolates. Copyright © 2007 by The American Society of Tropical Medicine and Hygiene.
CRISPR/Cas9 and Anther Culture for Precision Double Haploid Line Production in Controlled Environments
(John Wiley and Sons Inc, 2024) Avinash Sharma; Himanshu Pandey; Varucha Misra; Rajeev Kumar; Amit Vashishth; V.S. Devadas; A.K. Mall; Ashutosh; Megha Raghvan; Ajith Kumar Kesavan; Vishva Deepak Chaturvedi
The development of mapping populations and quantitative trait loci (QTL) analysis face constraints, in crops exhibiting male sterility and self-incompatibility under field conditions. Addressing these challenges requires the integration of advanced techniques, including the temporal alteration or excision of centromere histone H3 (CENH3) protein and the use of gene editing tools such as MATRILINEAL (MTL) knockout. Specifically, this can be achieved through Cas9/gRNA-mediated mutagenesis or Cas9/gRNA-driven promoter expression systems. These technologies offer efficient means to advance mapping populations and QTL analysis in male sterile and self-incompatible crops within controlled ecosystems. The doubled haploid (DH) mapping population, traditionally requiring 3 years of generation time via anther culture method, can now be expedited to 2–3 years of generation time using gene editing techniques within controlled environmental systems. Notably, DH mapping populations can be efficiently generated in various crops, including rice, wheat, maize, barley and oats by leveraging gene editing tools. Among these tools, the novel approach of CENH3 protein temporal alteration/excision emerges as highly efficient compared to MTL knockout using Cas9/gRNA-mediated mutation or Cas9/gRNA promoter expression. However, further investigation is warranted to optimise the regeneration of double haploid populations and enhance QTL analysis in male sterile and self-incompatible crops under controlled systems. © 2024 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.
Downregulation of mitogen-activated protein kinase 1 of Leishmania donovani field isolates is associated with antimony resistance
(2012) Ashutosh; Mansi Garg; Shyam Sundar; Robert Duncan; Hira L. Nakhasi; Neena Goyal
Emergence of resistance to pentavalent antimonials has become a severe obstacle in the treatment of visceral leishmaniasis (VL) on the Indian subcontinent. The mechanisms operating in laboratory-generated strains are somewhat known, but the determinants of clinical antimony resistance are not well understood. By utilizing a DNA microarray expression profiling approach, we identified a gene encoding mitogen-activated protein kinase 1 (MAPK1) for the kinetoplast protozoan Leishmania donovani (LdMAPK1) that was consistently downregulated in antimony-resistant field isolates. The expression level of the gene was validated by real-time PCR. Furthermore, decreased expression of LdMAPK1 was also confirmed at the protein level in resistant isolates. Primary structure analysis of LdMAPK1 revealed the presence of all of the characteristic features of MAPK1. When expressed in Escherichia coli, the recombinant enzyme showed kinase activity with myelin basic protein as the substrate and was inhibited by staurosporine. Interestingly, overexpression of this gene in a drug-sensitive laboratory strain and a resistant field isolate resulted in increased the sensitivity of the transfectants to potassium antimony tartrate, suggesting that it has a role in antimony resistance. Our results demonstrate that downregulation of LdMAPK1 may be in part correlated with antimony drug resistance in Indian VL isolates. Copyright © 2012, American Society for Microbiology. All Rights Reserved.
(+)-Epimaritidine, an alkaloid from Zephyranthes rosea
(1985) Shibnath Ghosal; Ashutosh; Sushma Razdan
The isolation and determination, by spectroscopic analyses and chemical correlation, of the structure and stereochemistry of (+)-epimaritidine, a new alkaloid from Zephyranthes rosea, is reported. A facile transformation of maritidine to (+)-epimaritidine is described and the mechanism is appraised in the light of the thermodynamic stability of the latter epimer. (+)-Epimaritidine comprises a missing link in the C-3 epimeric pairs of 5,10b-ethanophenanthridine alkaloids of the vittatine-haemanthamine type. © 1985.
Estimation of Domain Mean Using Conventional Synthetic Estimator with Two Auxiliary Characters
(Springer Science and Business Media Deutschland GmbH, 2023) Ashutosh
The estimation of domain mean is being accelerated applied to draft program policy in the government and private sectors. The use of two auxiliary characters is better choice as compared to single auxiliary character. The main interest is to consist information about an additional auxiliary character z in auxiliary character x and utilize for interested domain. This paper has investigated conventional generalized synthetic estimator for domain mean using two auxiliary characters x and z, and also discussed its properties. A comparative study of the proposed estimator has been made with the conventional ratio and conventional generalized estimators in terms of absolute relative bias and simulated relative standard error. It has evaluated, the proposed estimator is more efficient than the relevant estimators. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Evaluation of bread wheat (Triticum aestivum l.) for terminal heat tolerance
(Indian Society of Genetics and Plant Breeding, 2020) Stuti Krishna; Priyanka Upadhayay; Vinod Kumar Mishra; Shubhra N. Kujur; Monu Kumar; Punam S. Yadav; Parvin Kumar Mahto; Prashant Singh; Ashutosh; Sandeep Sharma; Ramesh Chand
Terminal heat tolerance of 34 wheat genotypes were analyzed for two years. Among 14 traits, canopy temperature, plot yield and days to heading were major components in clustering of genotypes. Three genotypes namely, DBW39, DBW16 and DBW14 had lowest heat susceptibility index (0.34-0.36) for plot yield and were considered as heat tolerant genotypes by both Hierarchical Cluster Analysis as well as Discriminant Analysis. These genotypes may serve as potential donors in wheat breeding to improve the terminal heat tolerance. © 2020, Indian Society of Genetics and Plant Breeding. All rights reserved.
GENERALIZED SYNTHETIC ESTIMATOR FOR DOMAIN MEAN IN TWO PHASE SAMPLING USING SINGLE AUXILIARY CHARACTER
(River Publishers, 2019) Ashutosh; B.B. Khare; S. Khare
In this paper, we have proposed a two phase sampling estimator for domain mean using auxiliary character with unknown X¯adomain mean. Also discussed properties of the proposed estimator for domain mean T ps,γ,ausing auxiliary character. Simulation study of the proposed estimator T ps,γ,ahas been made with conventional ratio synthetic estimator for domain mean T ps,-1,ausing auxiliary character in terms of simulated relative standard error (SRSE) and absolute relative bias (ARB). Simulation study shows that under synthetic assumption proposed estimator is more efficient than conventional ratio synthetic estimator for domain mean using auxiliary character. © 2020 River Publishers.
Genome-wide association study for powdery mildew resistance in CIMMYT's spring wheat germplasm
(John Wiley and Sons Inc, 2025) Deepa Bhadana; Prabhjot Kaur; Ramandeep P. Kaur; Vikas Kumar Ravat; Ashutosh; Rahul Kumar; Neeraj Kumar Vasistha
Powdery mildew (PM), caused by Blumeria graminis f. sp. tritici (Bgt), is a foliar disease of wheat (Triticum aestivum) that adversely affects both grain yield and quality. Growing resistant cultivars offers an effective and environmentally sustainable solution to managing PM. However, relying on the same genetic source of resistance can lead to resistance breakdown as Bgt isolates rapidly evolve. To mitigate this, identifying novel resistance sources is crucial. In this study, 225 diverse wheat genotypes were evaluated at adult plant stage in disease nurseries over the three crop seasons (2018/2019, 2019/2020 and 2020/2021). Using disease and genotyping data from 12,160 single-nucleotide polymorphism (SNP) markers, a genome-wide association study (GWAS) was conducted to identify novel resistance loci. We identified 22 marker loci significantly (at p < 0.005) associated with PM resistance, distributed across 14 wheat chromosomes (1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4B, 5D, 6A, 7A and 7B). Of these, seven loci overlap with previously identified regions, while the remaining 15 loci represent novel regions reported for the first time in this study. The identified SNP markers have significant potential for wheat breeding programmes, as they can accelerate the development of PM-resistant cultivars through marker-assisted selection. © 2024 British Society for Plant Pathology.
Marker-assisted foreground pyramiding of genes/QTL’s for grain quality and rust resistance genes in most popular wheat cv., HUW234 of Eastern Gangetic plains of India
(Springer, 2025) Ashutosh; Vinod Kumar Mishra; Kartikeya Srivastava; Monu Kumar; Prashant R. Singh
Marker-assisted foreground selection was employed to transfer four rust-resistant genes, Lr19/Sr25, Yr10, and Lr34, from HD2967 into the popular Indian wheat cultivar HUW234, which already possessed the quality traits, Gpc-B1 and HGW. Gene-specific SSR markers were utilized in each generation to confirm the presence of these target genes in the selected progeny. Fourteen families in the F5 generation were identified through foreground marker-assisted selection, these families were found homozygous for all the target genes and out of 14 families, 9 families were selected further as agronomically superior. In the subsequent F6 generation, again, these nine families were evaluated, and five agronomically superior new recombinant families were selected. These selected families displayed the desired quality traits, rust resistance, and high yield. Notably, these selected families demonstrated resistance to various rust pathotypes, including the most virulent pathotype 77 − 5 of leaf rust, as well as predominant pathotypes 238S119 and 40 A-1 for stripe and stem rust respectively. Of these nine families, five exhibited significantly higher grain yield and grain protein content compared to the original parent, HUW234. This suggests the potential for enhancing both grain quality and the durability of resistance against all three rust types in future wheat breeding programs. © The Author(s), under exclusive licence to Society for Plant Biochemistry and Biotechnology 2025.
Molecular mechanisms of antimony resistance in Leishmania
(2007) Ashutosh; Shyam Sundar; Neena Goyal
Leishmaniasis causes significant morbidity and mortality worldwide. The disease is endemic in developing countries of tropical regions, and in recent years economic globalization and increased travel have extended its reach to people in developed countries. In the absence of effective vaccines and vector-control measures, the main line of defense against the disease is chemotherapy. Organic pentavalent antimonials [Sb(V)] have been the first-line drugs for the treatment of leishmaniasis for the last six decades, and clinical resistance to these drugs has emerged as a primary obstacle to successful treatment and control. A multiplicity of resistance mechanisms have been described in resistant Leishmania mutants developed in vitro by stepwise increases of the concentration of either antimony [Sb(III)] or the related metal arsenic [As(III)], the most prevalent mechanism being upregulated Sb(III) detoxification and sequestration. With the availability of resistant field isolates, it has now become possible to elucidate mechanisms of clinical resistance. The present review describes the mechanisms of antimony resistance in Leishmania and highlights the links between previous hypotheses and current developments in field studies. Unraveling the molecular mechanisms of clinical resistance could allow the prevention and circumvention of resistance, as well as rational drug design for the treatment of drug-resistant Leishmania. © 2007 SGM.
NDVI and grain fill duration are important to be considered in breeding for terminal heat stress tolerance in wheat
(John Wiley and Sons Inc, 2023) Monu Kumar; Vinod Kumar Mishra; Ramesh Chand; Sandeep Sharma; Uttam Kumar; Jai Prakash Jaiswal; Mukesh Choudhary; Anima Mahato; Ashutosh; Prashant Singh; Arun Kumar Joshi
Terminal heat stress is a major constraint for taking a profitable crop of wheat by small and marginal farmers in the Indo-Gangetic Plains of south Asia. Hence, breeders remain in constant search for heat-tolerant genotypes. This study was done with the purpose to find out high-yielding wheat genotypes that perform stably under terminal heat stress as well as to conclude an easy phenotyping trait for this objective. A cross (HUW 234 × HUW 468) was made using two popular cultivars of the eastern Gangetic Plains of India. HUW 234 carries terminal heat tolerance whereas, HUW 468 is high yielding but suffers from terminal heat stress when planted late. So obtained 167 recombinant inbred lines (RILs) were exposed to both timely sown (TS) and late sown (LS) conditions at three locations for two consecutive years 2016–17 and 2017–18 at Varanasi (Uttar Pradesh), Jabalpur (Madhya Pradesh) and Pusa, Samastipur (Bihar). Combined ANOVA revealed that normalized difference vegetation index (NDVI) at anthesis stage (NDVI_AH) and grain filling duration (GFD) was significant for genotype (G), environment (E) and genotype × environment interaction (GEI). Likewise, differences were significant for grain yield (GY) and 1000-grain weight (TGW). AMMI analysis revealed similar results. However, NDVI_AH showed low variation under heat stressed late sown conditions. Furthermore, the which-won-where model and mean versus stability identified the best performing, above-average yielding and stable lines across the environments. Correlation among measured traits revealed that NDVI_AH had a significant association with GY in most of the environments. Several lines that performed superior to better parent for GY also showed higher values for NDVI_AH and GFD. The study demonstrates that NDVI_AH and GFD appear to be important traits to be considered while breeding for terminal heat stress tolerance in wheat. © 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.
Use of Leishmania donovani field isolates expressing the luciferase reporter gene in in vitro drug screening
(2005) Ashutosh; Suman Gupta; Ramesh; Shyam Sundar; Neena Goyal
Currently available primary screens for the selection of candidate antileishmanial compounds are not ideal. These techniques are time-consuming, laborious, and difficult to scale and require macrophages, which limit their use for high-throughput screening. We have developed Leishmania donovani field isolates that constitutively express the firefly luciferase reporter gene (luc) as a part of an episomal vector. An excellent correlation between parasite number and luciferase activity was observed. luc expression was stable, even in the absence of drug selection, for 4 weeks. The transfectants were infective to macrophages, and intracellular amastigotes exhibited luciferase activity. The suitability of these recombinant field isolates for in vitro screening of antileishmanial drugs was established. The luciferase-expressing sodium stibogluconate-resistant cell lines offer a model for the screening of compounds for resistance. The system is in routine use at the Central Drug Research Institute, Lucknow, India, for high-throughput screening of newly synthesized compounds. Copyright © 2005, American Society for Microbiology. All Rights Reserved.