Shanmugam, P. | Search bioRxiv

bioRxiv2026

Evidence of Filopodial translocation of Blastema associated microRNA rich Exosome like Extracellular Vesicles

Zebrafish (Danio rerio) possess remarkable regenerative capacity, making them an ideal model for studying the molecular mechanisms underlying tissue regeneration. In this article we report the identification of blastema linked exosome like extracellular vesicles (EVs) in zebrafish, that to the vesicles were plausibly being translocated in the proximo-distal axis through filipodia. We further thoroughly examined the exosome like EVs isolated from regenerating tissues of zebrafish caudal fins to characterize their nucleic acid cargo and evaluate their potential regulatory functions in regeneration. Caudal fins were amputated and allowed to regenerate and exosome like EVs isolated from blastema tissues displayed increased abundance compared to non-amputated controls. RNA sequencing identified a dynamic cluster of EV linked microRNAs (miRs). These differentially expressed miRs, including dre-miR-21, dre-miR-200b, dre-miR-218a and dre-let-7e were upregulated and associated with promoting proliferation, migration, differentiation, and tumour suppression pathways. Moreover, dre-miR-100, dre-miR-146a and dre-miR-200c regulated osteogenic differentiation, inflammatory signalling, epithelial-mesenchymal transition, and cell adhesion. Regeneration is generally believed to be coordinated only by local morphogen diffusion. Through this study it is indicative that filipodia bound EVs might have a pivotal role in long-range communication between blastema and the proximal tissues during the regeneration process. A detailed analyses of the miR targets and their validation could potentially lead to novel advancement and solutions in the field of regeneration and regenerative medicine in the near future.

Developmental Biology↗

bioRxiv2025

Whole genome analysis identified a cefotaxime-resistant Empedobacter brevis GBW-1 isolate from ground beef encoding a novel metallo-beta-lactamase variant, blaEBR-6

While investigating foodstuffs for ESBL-producing Aeromonas species on ampicillin dextrin agar with vancomycin and cefotaxime, a multidrug-resistant Empedobacter brevis strain GBW-1 was identified from ground beef. Phylogenetic analysis supports the interconnectedness of environment, humans and food driving this species evolutionary development. Antimicrobial susceptibility testing demonstrated resistance to gentamicin, carbapenems and third-generation cephalosporins. Whole genome sequencing of this strain detected a 3.74 Mb genome with 32.8% GC content containing 3,780 coding genes. Among these genes, at least three known antimicrobial resistance (AMR) genes were identified with qacG, vanT gene within the vanG cluster, and a novel variant of the metallo-{beta}-lactamase blaEBR-6. This novel homologue, EBR-6, was compared against previously known EBR variants and was found to be closest to EBR-3 with an 84.98% amino acid identity match. Docking software predicted these mutations vary the binding to meropenem. Furthermore, nearly 100 annotated regions associated with mobile genetic elements, including the presence of three, separate tra operons were identified on the genome. Together, these findings implicate the importance of horizontal gene transfer in the acquisition of AMR among the emerging pathogen Empedobacter brevis and further stress its One Health nature. ImportanceAs global trade and commerce continues to create a more interconnected world, the increasing frequency and spread of antimicrobial resistance amongst foodborne bacteria poses a significant challenge to public health. Here, we report the isolation of the multi-drug resistant Empedobacter brevis GBW-1, a bacterial strain harboring resistance against meropenem, third-generation cephalosporins, and gentamicin. Of particular note, this strain displays a novel variant of a metallo-{beta}-lactamase (MBL) gene, blaEBR-6, as well as three distinct tra operons, suggesting enhanced capacity of horizontal gene transfer. These findings highlight how foodborne bacteria may serve as reservoirs and vectors for the further spread of resistance genes, reinforcing the necessity of utilizing a collaborative One Health approach to combat AMR across sectors.

microbiology↗