PubMed Health⌕ Search

Biomedical subjects

Praveen Kumar

Publications and source records attributed to Praveen Kumar.

3 recordsLinked to original sources
PubMed2026

Multi-omics analysis to uncover constitutive priming and dynamic metabolic reprogramming conferring white rust resistance in Brassica juncea.

White rust, caused by Albugo candida, is one of the most devastating diseases of Indian mustard (Brassica juncea), causing yield losses of up to 90%. Durable resistance sources within cultivated Brassica germplasm remain limited. In this study, near-isogenic lines (NILs) of B. juncea cv. Varuna harbouring resistance from an East European source (Donskaja-IV, possessing a single CC-NB-LRR protein-coding R gene) was used to investigate the molecular basis of resistance through integrated transcriptomic and metabolomic analyses at 48 and 96 hours post-inoculation (hpi). Transcriptomic profiling revealed that the resistant Varuna_WRR line exhibited significantly higher unique transcript expression (18.76%) compared to the susceptible parent (8.41%) during the progression of infection. Principal component analysis showed clear separation between genotypes based on infection status, time, and genetic background. In the resistant line, upregulated genes were enriched in ethylene-activated signaling, protein phosphorylation, endoplasmic reticulum stress response, pectin biosynthesis, and hypersensitive response at 48 hpi, shifting toward programmed cell death, protein ubiquitination, abscisic acid metabolism, and starch biosynthesis at 96 hpi. Conversely, the susceptible line displayed broad downregulation of primary metabolic processes, indicating metabolic exhaustion. Metabolomic analysis demonstrated that the resistant genotype accumulated higher levels of defense-related amino acids (proline, glutamine, glutamic acid, serine, threonine, glycine), carbohydrates, organic acids, and polyamines, supporting enhanced nitrogen assimilation, energy reserves, membrane stability, and signaling. Together, these findings indicate that constitutive priming and dynamic activation of defense signaling, protein turnover, and osmoprotectant accumulation underpin the enhanced resistance in Varuna_WRR against Albugo candida. This integrated multi-omics approach provides valuable insights for breeding durable white rust resistance in Brassica juncea.

Brassica juncea↗
PubMed2025

The Data Distillery: A Graph Framework for Semantic Integration and Querying of Biomedical Data.

The Data Distillery Knowledge Graph (DDKG) is a framework for semantic integration and querying of biomedical data across domains. Built for the NIH Common Fund Data Ecosystem, it supports translational research by linking clinical and experimental datasets in a unified graph model. Clinical standards such as ICD-10, SNOMED, and DrugBank are integrated through UMLS, while genomics and basic science data are structured using ontologies and standards such as HPO, GENCODE, Ensembl, STRING, and ClinVar. The DDKG uses a property graph architecture based on the UBKG infrastructure and supports ontology-based ingestion, identifier normalization, and graph-native querying. The system is modular and can be extended with new datasets or schema modules. We demonstrate its utility for informatics queries across eight use cases, including regulatory variant analysis, tissue-specific expression, biomarker discovery, and cross-species variant prioritization. The DDKG is accessible via a public interface, a programmatic API, and downloadable builds for local use.

Journal Article↗
PubMed2025

Multi-Omics Analysis of Experimentally Evolved Candida auris Isolates Reveals Modulation of Sterols, Sphingolipids, and Oxidative Stress in Acquired Amphotericin B Resistance.

Clinical isolates of Candida auris show a high prevalence of resistance to Amphotericin B (AmB)-an uncommon trait in most Candida species. Alterations in ergosterol biosynthesis can contribute to acquired AmB resistance in C. auris laboratory strains but are rarely seen in clinical isolates. In this study, we experimentally evolved two drug-susceptible Clade II isolates of C. auris to develop AmB resistance. The evolved strains displayed a four to eight fold increase in MIC50 compared to the parental cells. We analyzed changes in their karyotype, genome, lipidome, and transcriptome associated with this acquired resistance. In one lineage, AOX2 was upregulated, and its deletion reversed the AmB resistance phenotype. The aox2Δ mutant also failed to evolve AmB resistance under experimental conditions. In the same lineage, restoring the UPC2 S332R and RTG3 S101T mutations to the wild-type allele restored AmB susceptibility. In another lineage, the ergosterol and sphingolipid pathways were observed to play a critical role, and upregulation of the ERG genes elevated the total sterol content, while significant downregulation of HSX11 (glucosylceramide synthase) resulted in lower levels of glucosylceramides. To our knowledge, this study is the first to show that AmB resistance in C. auris can be acquired through mechanisms both dependent on or independent of sterol content modulation, highlighting Aox2 and Upc2 as key regulators of amphotericin resistance.

Amphotericin B↗