Biology subjects

Barvkar, V. T.

Publications and source records attributed to Barvkar, V. T..

3 recordsLinked to original sources

bioRxiv2025

Trehalose Transport Dynamics Underpin a Metabolic Trade-Off between Exogenous Uptake and Endogenous Synthesis in Lepidopteran Insects

Trehalose is the major insect hemolymph sugar and plays a diverse role. Its level is regulated endogenously by the dynamics of biosynthesis and distribution by sugar transporters (STs). The metabolic trade-off between trehalose synthesis and uptake remains poorly understood, despite its critical role in homeostasis. Here, we examined the role of a gut-specific trehalose transporter, HaST46, in regulating this metabolic trade-off in Helicoverpa armigera, a Lepidopteran pest model. Integrated transcriptomics analysis and functional analyses revealed that HaST46 acts as a diet-responsive transporter, localised to the posterior midgut, with trehalose preference. Its expression is modulated in response to dietary trehalose availability, enhancing the efficient exogenous trehalose uptake while attenuating its endogenous synthesis and conserving energy. Functional perturbation through overexpression and silencing revealed a feedback-regulated mechanism in which HaST46 expression showed strong correlation with trehalose metabolising enzymes and other HaSTs isoforms to maintain systemic trehalose homeostasis. Overall, our findings reveal a metabolic trade-off between exogenous trehalose uptake and endogenous synthesis mediated by gut-specific sugar transporters.

physiology↗

bioRxiv2024

Biological activities and metabolic profile of endophytic Bacillus haynesii from Momordica charantia

Endophytes share a complex intimate relationship due to which they are capable of synthesizing metabolites that are either similar or derivative of host bioactive compounds. Such endophytes especially from medicinal plants can be prospected for commercial-scale production of the therapeutic compound. Thus, the study evaluates the antioxidant and anti-inflammatory potential of Momordica charantia fruit endophyte Bacillus haynesii R2MCFF61, and determines its metabolite profile through LC-Q-TOF-MS for the bioactive compounds produced. B. haynesii R2MCFF61 showed significant antioxidant and anti-inflammatory potential with increased DPPH scavenging activity in the standard compound and inhibition of protein denaturation respectively. The metabolic profile of this endophyte showed 23 compounds, mostly consisting of metabolites from lipid, phenylpropanoid and triterpenoid pathways. B. haynesii R2MCFF61 showed production of cucurbitane-triterpenoids namely Momordicoside K, 19-dimethoxycucurbita-5(10),6,22(E),24-tetraen-3{beta}-ol and 23(E)-7{beta}-methoxycucurbita-5,23,25-trien-3{beta}-ol. These compounds are mainly produced by M. charantia fruit and their production by its endophyte is reported for the first time. Thus, these results indicate the promising therapeutic potential of B. haynesii R2MCFF61 which can be utilized as a low-cost sustainable source of these bioactive compounds.

microbiology↗

bioRxiv2024

Evaluation of extraction solvents for untargeted metabolomics to decipher the DOM of Antarctic cryoconite holes

Cryoconite holes are biological hotspots with a high biogeochemical turnover rate, contributing significantly to the glacial ecosystems overall carbon cycles and net fluxes. Unfortunately, the information about the composition of low molecular weight molecules formed through the metabolic processes of cryoconite-dwelling microbes is scanty. These molecules constitute a substantial portion of the dissolved organic matter (DOM) within cryoconite holes. The present study investigated the composition of DOM in cryoconite holes using reverse-phase liquid chromatography (RP-LC) coupled with high-resolution tandem mass spectrometry. We evaluated various solvent combinations of water, methanol, and acetonitrile to extract chemically diverse polar and non-polar metabolites from the cryoconite holes. Among the single solvents, organic-rich MeOH: Water (70:30 v/v) and in parallel 2-single solvent combinations of MeOH: Water (70:30 v/v) and Acetonitrile: Methanol: Water (40:40:20 v/v) provided increased number and chemical diversity of extracted metabolites. Combining RP with the hydrophilic interaction liquid chromatography (HILIC) technique provided the highest number of unique metabolites. This dual-LC and ionization polarity combination increased the detection of metabolic features by 46.96% and 24.52% in single- and two-solvent combinations compared to RP alone. This study developed a simple untargeted metabolomics workflow that is highly sensitive and robust, detecting and potentially identifying a large number of chemically diverse molecules present in the DOM (extracellular) and microbes (intracellular) from the cryoconite holes environment. This method can better characterize DOMs chemical composition and, after integrating with other omics approaches, can be used to examine the link between metabolic pathways and microbial communities in global cryoconite holes or other similar ecosystems, revealing how these earthy systems and their microbial flora control carbon or nutrient storage or release in response to global climate change. Overall, the study presents a valuable methodology for studying the biogeochemistry of cryoconite holes.

microbiology↗