Biology subjects

Asokan, N.

Publications and source records attributed to Asokan, N..

6 recordsLinked to original sources

bioRxiv2026

MOLECULAR INSIGHTS INTO PESTICIDE TOLERANCE: PROTEIN INDUCTION AND DNA DAMAGE IN ORGANOPHOSPHATE-DEGRADING BACTERIA

One of the effects of the intensified agricultural activities involves environmental pollution by pesticides, which are bound to get into the soil and ultimately into the water sources through leaching. The recurrent exposure of soil microbiota to these poisonous substances facilitates the process of adaptive resistance and catabolic functions. In the current research, bacterial cultures taken in Karuppur and Salem pesticide-contaminated agricultural soils were filtered on their capability to decompose organophosphate pesticides. Two strong isolates, which were referred to as Bacillus sp. and Micrococcus sp. had a great level of tolerance and degradation capacity. Significant biomolecular changes in these isolates were observed after long-term exposure (three months) to organophosphate pesticides. A protein estimation showed a strong rise in the overall total protein content indicating the activation of stress-related and degradative enzymes. Genomic DNA damage was identified by DNA ladder assay, which is a genotoxic stress caused by pesticides. Thus, plasmid profiling also revealed a rise of copy number and change of the size of plasmids, implying potential adaption through plasmids and greater degradation potential. This evidence indicates that long-term exposure to pesticides leads to microbial adaptation in terms of physiological and genetic changes to allow survival in adverse environments. The isolates identified have great potential to be used in bioremediation strategies that will be used in detoxifying the soils that have been contaminated with organophosphate.

microbiology↗

bioRxiv2026

SUSTAINABLE MICROBIAL BIOTRANSFORMATION OF CR(VI) TO CR(III) IN TANNERY EFFLUENT AND ITS VALORIZATION INTO CR(III) NANOPARTICLES VIA TRIDAX PROCUMBENS-MEDIATED GREEN SYNTHESIS

Environmental pollution from leather industries have become a menace. The microbial remediation of industrial waste and its reuse for agriculture could be a beneficial outcome. In present study, the bioremediated Cr III in the effluents are further converted to value product - Chromium oxide NP. This ensures double edged benefit as effluent is bioremediated and Chromium oxide NP with several applications is derived. A noteworthy advancement of the research involved the green synthesis of chromium oxide nanoparticles using Tridax procumbens. The effluent bioremediated can be used for agricultural purposes. By effectively characterizing tannery effluent and isolating chromium-tolerant bacteria, the study not only demonstrate a practical bioremediation solution but also showcase the potential of green synthesis in producing chromium oxide nanoparticles. In conclusion, this research marks a significant advancement in environmental science, leveraging both biological and nanotechnological innovations to address pressing challenges in pollution control. The present study focuses on a novel process of obtaining chromium oxide nanoparticle from tannery effluent with several applications derived from bioremediated tannery effluent using a cost-effective and eco-friendly process. The nanoparticle has a stable particle size and exhibit antioxidant, anti-diabetic properties. This product offers a breakthrough solution for the leather industry and healthcare sector. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/720289v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@192e96borg.highwire.dtl.DTLVardef@1aae28org.highwire.dtl.DTLVardef@19fd282org.highwire.dtl.DTLVardef@1b562f9_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2025

Serum albumin coated stellate mesoporous silica nanocomposites inhibit metastatic outgrowth in zebrafish embryos

Mesoporous silica-based nanoparticles (NPs) are promising tools for developing targeted therapeutic interventions in cancer. Endowed with a large pore silica shell suitable for drug encapsulation and with a responsive magnetic core, iron oxide stellate mesoporous silica (IO STMS) NPs stand out. Yet, their impact and potential toxicity on relevant in vivo models has not been carefully tested yet. Herein, we assessed the impact of these IO STMS nanocomposites in a syngeneic metastasis assay in zebrafish. NPs were surface-modified with human serum albumin (HSA) and loaded or not with the chemotherapeutic doxorubicin (DOX). In vitro, DOX-loaded NPs were expectedly more toxic to zebrafish melanoma (Zmel) cells than no-DOX NPs. In zebrafish embryos, the NPs were rapidly distributed through blood circulation and were found to colocalize over time with the vascular endothelium and local macrophages. Suprisingly, the NPs efficiently reduced the outgrowth of Zmel tumoral masses in an experimental metastasis assay in zebrafish embryos regardless of their loading with DOX. The anti-metastatic effect of these NPs was further improved by increasing the amount of HSA coating, also resulting in higher embryo survival. Altogether, IO STMS NPs showed promising cytotoxic effects on a relevant zebrafish metastasis model, inhibiting metastatic outgrowth in vivo independently of the drug loading. This opens the door to further testing for better exploiting their targeting and drug delivery potentialities.

cancer biology↗

bioRxiv2023

Peripheral positioning of lysosomes supports melanoma aggressiveness

Emerging evidences suggest that function and position of organelles are pivotal for tumor cell dissemination. Among them, lysosomes stand out as they integrate metabolic sensing with gene regulation and secretion of proteases. Yet, how their function is linked to their position and how this controls metastasis remains elusive. Here, we analyzed lysosome subcellular distribution in patient-derived melanoma cells and patient biopsies and found that lysosome spreading scales with their aggressiveness. Peripheral lysosomes promote matrix degradation and invasion of melanoma cells which is directly linked to their lysosomal and cell transcriptional programs. When controlling lysosomal positioning using chemo-genetical heterodimerization in patient-derived melanoma cells, we demonstrated that perinuclear clustering impairs lysosomal secretion, matrix degradation and invasion. Impairing lysosomal spreading in two distinct in vivo models (mouse and zebrafish) significantly reduces invasive outgrowth. Our study provides a direct demonstration that lysosomal positioning controls cell invasion, illustrating the importance of organelle adaptation in carcinogenesis and suggesting that lysosome positioning could potentially be used for the diagnosis of metastatic melanoma.

cell biology↗

bioRxiv2022

Blood flow diverts extracellular vesicles from endothelial degradative compartments to promote angiogenesis

Extracellular vesicles released by tumors (tEVs) disseminate via circulatory networks and promote microenvironmental changes in distant organs favoring metastatic seeding. Despite their abundance in the bloodstream, how hemodynamics affect the function of circulating tEVs remains unsolved. We experimentally tuned flow profiles in vitro (microfluidics) and in vivo (zebrafish) and demonstrated that efficient uptake of tEVs occurs in endothelial cells subjected to capillary-like hemodynamics. Such flow profiles partially reroute internalized tEVs towards non-acidic and non-degradative Rab14-positive endosomes, at the expense of lysosomes, suggesting that endothelial mechanosensing diverts tEVs from degradation. Subsequently, tEVs promote the expression of pro-angiogenic transcription factors in flow-stimulated endothelial cells and favor vessel sprouting in zebrafish. Altogether, we demonstrate that capillary-like flow profiles potentiate the pro-tumoral function of circulating tEVs by promoting their uptake and rerouting their trafficking. We propose that tEVs contribute to pre-metastatic niche formation by exploiting endothelial mechanosensing in specific vascular regions with permissive hemodynamics.

cell biology↗

bioRxiv2017

Continuous high-resolution in vivo imaging reveals tumor-specific dissemination in an embryonic zebrafish xenograft model

Mechanisms mediating tumor metastasis are crucial for diagnostic and therapeutic targeting. Here, we take advantage of a transparent embryonic zebrafish xenograft model (eZXM) to visualize and track injected human leukemic and breast cancer cells in real time using selective plane illumination microscopy (SPIM) for up to 30 hours. Injected cells exhibited disease-specific patterns of intravascular distribution with leukemic cells moving faster than breast cancer cells. While breast cancer cells predominantly adhered to nearby regions, about 30% invaded the avascularized tissue, reminiscent of their metastatic phenotype. Survival of the injected tumor cells was partly inhibited by the cellular innate immune system of the recipient embryos and leukemic cell dissemination was effectively inhibited by pharmacological ROCK1 blockade. These observations, and the ability to image several embryos simultaneously, support the use of eZXM and SPIM imaging as a functional screening platform to identify compounds that restricts cancer cell spread and invasion.

cancer biology↗