Biology subjects

Yadav, J.

Publications and source records attributed to Yadav, J..

6 recordsLinked to original sources

bioRxiv2023

Unravelling the novel genetic diversity and marker-trait associations of corn leaf aphid resistance in wheat using microsatellite markers

The study was conducted to identify novel simple sequence repeat (SSR) markers associated with resistance to corn aphid (CLA), Rhopalosiphum maidis L. in 48 selected bread wheat (Triticum aestivum L.) and wild wheat (Aegilops spp. & T. dicoccoides) genotypes during two consecutive cropping seasons (2018-19 and 2019-20). A total of 51 polymorphic markers containing 143 alleles were used for the analysis. The frequency of the major allele ranged from 0.552 (Xgwm113) to 0.938 (Xcfd45, Xgwm194 and Xgwm526), with a mean of 0.731. Gene diversity ranged from 0.116 (Xgwm526) to 0.489 (Xgwm113), with a mean of 0.354. The polymorphic information content (PIC) value for the SSR markers ranged from 0.107 (Xgwm526) to 0.370 (Xgwm113) with a mean of 0.282. The results of the STRUCTURE analysis revealed the presence of four main subgroups in the populations. Analysis of molecular variance (AMOVA) showed that the between-group difference was around 37% of the total variation contributed to the diversity by the whole germplasm, while 63% of the variation was attributed between individuals within the group. A general linear model (GLM) was used to identify marker-trait associations, which detected a total of 23 and 27 significant new marker-trait associations (MTAs) at the p < 0.01 significance level during the 2018-19 and 2019-20 crop seasons, respectively. The findings of this study have important implications for the identification of molecular markers associated with CLA resistance. These markers can increase the accuracy and efficiency of aphid-resistant germplasm selection, ultimately facilitating the transfer of resistance traits to desirable wheat genotypes.

molecular biology↗

bioRxiv2022

Periodic Environmental Disturbance Drives Repeated Ecomorphological Diversification in an Adaptive Radiation of Antarctic Fishes

The ecological theory of adaptive radiation has profoundly shaped our conceptualization of the rules that govern diversification. However, while many radiations follow classic early burst patterns of diversification as they fill ecological space, the longer-term fates of these radiations depend on many factors, such as climatic stability. In systems with periodic disturbances, species-rich clades can contain nested adaptive radiations of subclades with their own distinct diversification histories, and how adaptive radiation theory applies in these cases is less clear. Here, we investigated patterns of ecological and phenotypic diversification within two iterative adaptive radiations of cryonotothenioid fishes in Antarcticas Southern Ocean: crocodile icefishes and notoperches. For both clades, we observe evidence of repeated diversification into disparate regions of trait space between closely related taxa and into overlapping regions of trait space between distantly related taxa. We additionally find little evidence that patterns of ecological divergence are correlated with evolution of morphological disparity, suggesting that these axes of divergence may not be tightly linked. Finally, we reveal evidence of repeated convergence in sympatry that suggests niche complementarity. These findings reflect the dynamic history of Antarctic marine habitats, and may guide hypotheses of diversification dynamics in environments characterized by periodic disturbance.

evolutionary biology↗

bioRxiv2020

Early induction of antibacterial activities distinguishes response of mice to infection with non-permissive from response to permissive Salmonella

Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid in humans, shares very high homology with closely related serovar, S. Typhimurium. Yet, unlike S. Typhimurium, S. Typhi does not establish infection in mice, the reasons for which are not well understood. Here, we present evidence that unlike S. Typhimurium, S. Typhi brings about induction of extracellular and intracellular antibacterial activities in mice. Cell-free peritoneal fluids from S. Typhi but not S. Typhimurium-infected mice inhibited replication of Salmonella ex vivo. The production of this activity was reduced in presence of serine protease inhibitor, phenylmethylsulfonlyl fluoride (PMSF). PMSF also inhibited generation of antibacterial activity released from in vitro S. Typhi - infected peritoneal macrophages in a cell death - dependent manner. Intracellularly, infection with S. Typhi in vitro as well as in vivo resulted in increased mRNA levels of iron-regulating molecules, ferroportin and lipocalin. These results suggest that induction of antibacterial molecules early on in mice in response to S. Typhi may prevent establishment of infection with this Salmonella serovar.

immunology↗

bioRxiv2020

Viscoelasticity of single macromolecules using Atomic Force Microscopy

We measured viscoelasticity of single protein molecules using two types of Atomic Force Microscopes (AFM) which employ different detection schemes to measure the cantilever response. We used a commonly available deflection detection scheme in commercial AFMs which measures cantilever bending and a fibre-interferometer based home-built AFM which measures cantilever displacement. For both methods, the dissipation coefficient of a single macromolecule is immeasurably low. The upper bound on the dissipation coefficient is 5 x 10-7 kg/s whereas the entropic stiffness of single unfolded domains of protein measured using both methods is in the range of 10 mN/m. We show that in a conventional deflection detection measurement, the phase of bending signal can be a primary source of artefacts in the dissipation estimates. It is recognized that the measurement of cantilever displacement, which does not have phase lag due to hydrodynamics of the cantilever, is better suited for ensuring artefact-free measurement of viscoelasticty compared to the measurement of the cantilever bending. We confirmed that the dissipation coefficient in single macromolecules is below the detection limit of AFM by measuring dissipation in water layers confined between the tip and the substrate using similar experimental parameters. Further, we experimentally determined the limits in which the simple point-mass approximation of the cantilever works in off-resonance operation. Significance StatementSingle Macromolecules, including unfolded proteins bear rubber-like entropic elasticity and internal friction characterized by finite dissipation coefficient. Direct measurement of this viscoelastic response is important since it plays a significant role, both in polymer physics as well as protein folding dynamics. The viscoelastic response of single polymer chain is difficult and prone to artefacts owing to the complications of hydrodynamics of macroscopic probe itself in the liquid environment. Using a special atomic force microscope, which allows quantitative estimate of viscoelasticity in liquid environments, we measured viscoelastic response of single molecule of Titin. We report here that the dissipation coefficient is below the detection limit of our experiments - with upper bound which is less than reported values in the literature.

biophysics↗

bioRxiv2020

Loss of clathrin heavy chain enhances actin-dependent stiffness of mouse embryonic stem cells

Mouse embryonic stem cells (mESCs) display unique mechanical properties, including low cell stiffness, and specific responses to features of the underlying substratum. Using atomic force microscopy (AFM), we demonstrate that mESCs lacking the clathrin heavy chain (Cltc), display higher Youngs modulus, indicative of greater cellular stiffness, in comparison to WT mESCs. We have previously shown that mESCs lacking Cltc display a loss of pluripotency, and an initiation of differentiation. The increased stiffness observed in these cells was accompanied by the presence of actin stress fibres and accumulation of the inactive, phosphorylated, actin binding protein, Cofilin. Treatment of Cltc knockdown mESCs with actin polymerization inhibitors resulted in a decrease in the Youngs modulus, to values similar to those obtained with WT mESCs. However, the expression profile of pluripotency factors was not rescued. This indicates that a restoration of mechanical properties, through modulation of the actin cytoskeleton, may not always be accompanied by a change in the expression of critical transcription factors that regulate the state of a stem cell, and that this may be dependent on the presence of active endocytosis in a cell.

cell biology↗

bioRxiv2017

Sex Specific Molecular Responses Of Quick-To-Court In Indian Malarial Vector Anopheles culicifacies: Conflict Of Mating And/Or Blood Feeding?

Understanding the molecular basis of mosquito behavioral complexity is central to the design of novel molecular tool to fight against their vector borne diseases. Although, olfactory system play important role to guide and manage many behavioral co-ordinates including feeding, mating, breeding etc., but the sex specific regulation of olfactory responses remains unanswered. From our ongoing transcriptomic data annotation of blood fed adult female olfactory tissue of A. culicifacies mosquito, we identified a 383 bp long unique transcript encoding Drosophila homolog of Quick-To-Court protein, previously shown to regulate the courtship behavior in adult male Drosophila. A comprehensive in silico analysis predicts Ac-qtc is 1536 bp long single copy gene encoding 511 AA long protein, having high degree of conservation with other insect homolog. Age dependent increased expression of putative Ac-qtc in the naive mosquitoes correlates the maturation of olfactory system, necessary to meet sex specific conflicting demand of mating (mate finding) vs. host-seeking behavioral responses. Though, 16-18 hour of starvation did not altered Ac-qtc expression in both the sexes, however blood feeding significantly modulated its response in the adult female mosquitoes, confirming that it may not be involved in sugar feeding associated behavioural regulation. Finally, a behavioural-cum-molecular assay indicated that natural dysregulation of Ac-qtc in late evening may promotes key mating event of successful insemination process. We hypothesize that Ac-qtc may play unique role to meet and manage the sex specific conflicting demand of mosquito courtship behaviour and/or blood feeding behaviour in the adult female mosquitoes. A molecular mechanism elucidation may provide new knowledge to consider Ac-qtc as a key molecular target for mosquito borne disease management.

animal behavior and cognition↗