Biology subjects

Kumar, R. S.

Publications and source records attributed to Kumar, R. S..

6 recordsLinked to original sources

bioRxiv2026

Navigating a dynamic winterscape: habitat composition and individual variability shape daily movement in wintering common cranes in western India

Wintering migratory birds must balance energetic requirements, resource availability, and disturbance in increasingly human-modified landscapes. However, individual-level variability in daily movement and winter space use remains poorly understood in populations of the Common Crane wintering in South Asia. We investigated how seasonal dynamics, landscape composition, and individual differences structure winter movement ecology in a semi-arid agro-wetland system in western India. We analysed high-resolution GPS telemetry data from four tagged cranes tracked across three consecutive winters. Daily movement distances were modelled using mixed-effects approaches to partition variance within and among individuals and among winters. Daily movement trajectories were evaluated using non-linear temporal terms. Landscape predictors, including the proportion of cropland, built-up area, and habitat heterogeneity, were incorporated to assess environmental drivers. Winter utilisation distributions were estimated using dynamic Brownian bridge movement models. Daily movement distance followed a non-linear seasonal pattern consistent with shifts in the profitability of agricultural resources over winter. Cropland proportion and landscape evenness were negatively associated with movement distance, whereas a high proportion of built-up areas increased daily movement distance, reflecting a trade-off between resource concentration and anthropogenic disturbance. Winter utilisation distribution size varied markedly both within individuals across years and among individuals within seasons. Winter movement and space use in Common Cranes are predominantly context-dependent and environmentally driven. Seasonal dynamics, agricultural landscapes, and human disturbance jointly structure movement patterns, with limited but consistent individual differences. While limited by sample size, this multi-year, individual-based telemetry provides insight into winter spatial strategies of Common Cranes in dynamic semi-arid agro-wetland systems.

ecology↗

bioRxiv2025

Seasonally differential migration strategies, detour, and bottleneck in Common Crane Grus grus wintering in western India

BackgroundThe Common Crane Grus grus, being widely distributed, abundant, and relatively easy to monitor, with long-distance migrations across diverse and sensitive habitats, is well-suited as a sentinel species for assessing the ecological integrity of the Central Asian Flyway (CAF). While migration routes and stopover sites of the Common Crane in the CAF are documented, seasonal variations in migration strategies, potential detours, bottlenecks, and stopover habitat selection - important factors for flyway conservation planning - remain poorly understood. To address this, we tracked five individuals from Gujarat, western India, to breeding sites in southwestern Siberia using solar-powered GPS-GSM transmitters, enabling high-resolution, multi-season analysis of their migration strategies, routes, timing, detours, bottlenecks, and stopover habitat selection. ResultsThe results highlighted seasonally differential migration strategies in Common Cranes. The analyses confirmed significant seasonal differences: Spring migration covered greater distances, lasted longer, and was slower, with higher stopover duration and reduced straightness. The observed migration routes deviated significantly from the simulated straight-line path, forming distinct detours likely to avoid the Hindu Kush mountains and take advantage of resource-rich areas. These detours resulted in routes that were 23.3% longer in autumn and 36.8% longer in spring compared to the shortest possible path. The tagged Common Cranes followed distinct seasonal migration routes that converged in Turkmenistan, creating migratory bottlenecks in Southern Turkmenistan, Afghanistan and Pakistan. At migration stopover sites, Common Cranes showed the highest probability of habitat use in bare ground (0.18) and cropland (0.13), suggesting a preference for open landscapes by the species. ConclusionOur findings reveal the adaptive strategies of Common Cranes in response to seasonal and topographical challenges. Cranes undertake substantial detours to optimize energy expenditure and access favorable stopover habitats. The identification of migratory bottlenecks in Turkmenistan, Afghanistan and Pakistan highlights the regions critical importance for conservation efforts for migratory birds.

ecology↗

bioRxiv2024

Analysis of Curcumin and Piperine for Breast Cancer Prevention and Treatment via Simulation and Artificial Intelligence Methods

From published literature, the combined properties of Curcumin and Piperine infers that the two molecules are potential preventative agents. The nutraceutical combination of Curcumin and Piperine may aid in breast cancer prevention by enhancing Curcumins anti-inflammatory and antioxidant effects. In this paper, we demonstrate the following analysis on these two nutraceutical drug molecules in the effort to replicate these inferences in-silico: Drug Synergy Analysis, Molecular Docking and Simulation of Dose-Response curves. We have predicted the synergy (i.e., the effect of two drug molecules when administered simultaneously) between the two molecules on the basis of the Bliss Additivity Score. These scores have been predicted by devising a deep learning model using neural networks to determine that the two molecules of interest are synergetic in nature (i.e., one molecule improves the effectiveness of the other). The data used for this model has been extracted from the DrugComb database and filtered to having drug combinations under the MCF7 cell line. The drug molecules are converted from its original SMILES representation to the ECFP6 molecular fingerprint format prior to training the data with the output feature as the Bliss score. In this work we also study the interactions between the molecules of interest and protein targets which are of interest (TRPV1 and STAT3) via Molecular Docking. From this, we have been able to determine the binding affinity of the two ligands of interest by docking simultaneously. We have also identified the coordinates of the binding sites of the respective ligands and other potential binding sites for effective binding. From the binding free energies simulated from molecular docking, we have derived the IC50 values using the Cheng-Prusoff Equation. From these IC50 values we have derived the monotherapy dose-response curves with respect to the activation of each the protein targets and the molecules of interest over a range of molar concentrations (0.01um to 100um) using the 4 - parameter logistic curve equation. Furthermore, we have devised a 3D heatmap indicating the combined effectiveness of Curcumin and Piperine from the 4 - parameter log - logistic curve of the Loewes Additivity Model over each of the protein targets in focus.

bioinformatics↗

bioRxiv2024

Steroidal glycoalkaloid biosynthesis and fungal tolerance are regulated by ELONGATED HYPOCOTYL 5, SlHY5, in tomato

Tomato (Solanum lycopersicum L.) is one of the highest consumable fruit crops, rich in nutrients, and has been an important target for enhancing the accumulation of various metabolites. Tomato also contains cholesterol-derived molecules, steroidal glycoalkaloids (SGAs), which contribute to pathogen defence but are toxic to humans and considered anti-nutritional compounds. Previous studies suggest the role of various transcription factors in SGA biosynthesis; however, the role of light and associated regulatory factors has not been studied in tomatoes. Here, we demonstrated that SGA biosynthesis is regulated by light through the ELONGATED HYPOCOTYL 5 homolog, SlHY5, by binding to light-responsive G-boxes present in the promoters of the structural and regulatory genes. Our analysis suggests that SlHY5 could complement the Arabidopsis thaliana and Nicotiana tabacum, hy5 mutants at molecular, morphological, and biochemical levels. We report the development of CRISPR/Cas9-based knockout mutant plants of tomato, slhy5CR, and show down-regulation of the SGA and phenylpropanoid pathway genes leading to a significant reduction in SGA (-tomatine and dehydrotomatine) and flavonol contents, whereas SlHY5 overexpression (SlHY5OX) plants show opposite effect. An enhanced SGA and flavonol levels in SlHY5OX lines provided tolerance against Alternaria solani fungus, while SlHY5CR was susceptible to the pathogen. This study advances our understanding of the HY5-dependent light-regulated biosynthesis of SGAs and flavonoids and their role in biotic stress in tomatoes. One Sentence SummaryLight-associated transcription factor, ELONGATED HYPOCOTYL 5, regulates biosynthesis of anti-nutrient molecules, steroidal glycoalkaloids, and fungal tolerance in tomato

molecular biology↗

bioRxiv2022

miRNA408 and its encoded peptide, miPEP408, regulate arsenic stress response in Arabidopsis

MicroRNAs (miRNAs) are small non-coding RNAs that play a central role in regulating various developmental and biological processes. The expression of miRNAs is differentially modulated in response to various stresses. Based on the recent findings, it has been shown that some of the pri-miRNAs encode small regulatory peptides, microRNA-encoded peptides (miPEP). miPEPs are reported to regulate the growth and development of plants by modulating corresponding miRNA expression; however, the role of these peptides in different stresses has not been explored yet. Here, we reported that pri-miR408 encodes a small peptide, miPEP408, that regulates the expression of miR408, its targets, and associated phenotype in Arabidopsis. Plants overexpressing miR408 showed severe sensitivity under low sulphur (LS), Arsenite As(III) and LS+As(III) stress, while miR408 mutant developed through the CRISPR/Cas9 approach showed tolerance. Transgenic lines showed phenotypic alteration and modulation in the expression of genes involved in the sulphur reduction pathway and affect sulphate and glutathione accumulation. Similar to miR408 overexpressing lines, the exogenous application of synthetic miPEP408 or miPEP408 overexpression led to sensitivity in plants under LS, As(III) and combined LS+As(III) stress compared to control. This study suggests the involvement of miR408 and miPEP408 in heavy metal and nutrient deficiency responses. One-sentence summarymiR408 and peptide encoded by miR408, miPEP408, regulate arsenic stress and low sulphur responses in Arabidopsis.

plant biology↗

bioRxiv2020

"Tracking the Rain Bird": Modeling the monthly distribution of Pied cuckoo in India

Pied cuckoo Clamator jacobinus (Boddart, 1783) is a migratory, brood-parasitic bird found in the African and Indian Subcontinent. Although the southern Indian population is presumably resident, the North Indian Population migrates from Africa to India during the summer. The arrival of the bird is linked to the onset of monsoon in India from scientific literature to folklore. It is known to make its appearance in central and northern India in the last week of May or early June, indicating the imminent arrival of the monsoon with its unmistakably loud metallic calls. There have been few attempts to compile relevant information on the species migration in the early 1900s and citizen science approach by Bird-count India; little information is available on how environmental factors might be affecting its migration. Here, we have used Maximum Entropy modeling to identify the monthly and seasonal distribution patterns and major bioclimatic factors that might be influencing the distribution of the species in India. We have used E-Bird citizen science platform data, seven bioclimatic variables, and monthly NDVI of respective months for building the models. The predicted output shows the species presence throughout the year in southern India. In contrast, in northern India, the distribution is dynamic, peaking in summers in the Month of May-June and no presence in winter. The influence of bioclimatic variables used in SDM varied monthly; Water vapor pressure was the primary contributing variable in the months prior to species arrival. In July, it was NDVI (Higher NDVI suggests abundance of food resources for the species). In August-September, Windspeed and water vapor pressure (Factors might be responsible for the departure of the species) have contributed highest. Our approach provides a more concise understanding of Pied cuckoos monthly distributions throughout India, which helps understand the complex seasonal shifts in the distribution of such migratory birds.

ecology↗