Biology subjects

Jeyarajan, S.

Publications and source records attributed to Jeyarajan, S..

6 recordsLinked to original sources

bioRxiv2025

Synergistic Antimicrobial Activity of Epinecidin-1 and Its Variants with Antibiotics Against Nosocomial Pathogens: Implications for In Vivo Wound Healing

In this study, we investigated the antimicrobial properties of the antimicrobial peptide (AMP) epinecidin-1 and its variants against a range of nosocomial bacterial pathogens. The bacteriostatic effects on Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus pneumoniae, and Staphylococcus aureus were evaluated using the microbroth dilution technique. Mechanistic insights into the antimicrobial action were studied through acridine orange and ethidium bromide (AO/EtBr) staining, which revealed the ability of AMPs to form pores in bacterial membranes. Furthermore, the wound healing efficacy of these peptides was assessed in vivo using rat model, where they significantly accelerated the healing process. Following the identification of their bacteriostatic activity against pathogenic strains, we also examined the effects of combining these AMPs with conventional antibiotics, namely ampicillin, kanamycin, and vancomycin. Epinecidin-1 and its variants displayed synergistic and additive interactions with these antibiotics at certain concentrations. This combination approach is particularly promising for treating infections in both human and livestock populations, thereby potentially mitigating the risk of environmental pathogen outbreaks and complications of multidrug resistance. In summary, our findings suggest that epinecidin-1 and its variants not only exhibit potent antimicrobial and wound healing properties but also enhance the efficacy of traditional antibiotics. These characteristics make them strong candidates for clinical and industrial applications aimed at managing bacterial pathogenicity.

bioengineering↗

bioRxiv2025

Tagging fluorescent reporter to epinecidin-1 antimicrobial peptide

In this study, we successfully cloned the fluorescent proteins eGFP and DsRed in-frame with the antimicrobial peptide epinecidin-1 (FIFHIIKGLFHAGKMIHGLV). The cloning strategy involved inserting the fluorescent reporters into the expression vector, followed by screening of positive clones through visual fluorescence detection and molecular validation. The visually identified fluorescent colonies were found positive with PCR and plasmid migration assay confirming successful cloning. This fusion of fluorescent reporters with a short antimicrobial peptide enables real-time visualization and monitoring of the peptides mechanism of action on membranes and within cells, both in vivo and in vitro. The fusion of eGFP and DsRed to epinecidin-1 did not impair the expression or fluorescence of the reporter protein.

molecular biology↗

bioRxiv2024

Antifungal activity of protamine

Background/ObjectiveAntimicrobial peptides (AMPs) are important innate defense molecules having wide spectrum of bioactivities like antibacterial, antifungal, antiparasitic and antiviral activities. The primary role of AMPs is to exert cytotoxicity on the invading pathogenic microorganisms and serve as immune modulators in higher organisms. Protamine is a polycationic peptide found in the nuclei of sperm in different vertebrate species has also antimicrobial activities. Protamine is thought to disrupt the cytoplasmic membrane caused by electrostatic interactions between the highly positively charged molecule and the negatively charged microbial cell surfaces. In addition to this, it is involved in wound healing activity and recruit leucocytes and modulators during inflammation. The present study proposes to investigate the anticandidal effects of protamine on clinical isolates of Candida spp. For experimental evaluation of anticandidal and antibiofilm activity, Minimal inhibitory concentration (MIC) was determined against Candida albicans, Candida tropicalis and Candida krusei. Protamine inhibited the growth of all the tested Candida spp. pathogens in respective MIC of 16 g ml-1, 32 g ml-1 and 256 g mg-1. After MIC determination, the mechanism of action was evaluated by assessing structural and cellular biochemical changes. The structural changes were examined by scanning electron microscopy (SEM) after treating C. albicans with protamine and SEM images clearly showed membrane rupture indicating that the peptide targets the membrane. Biochemical changes like induction of reactive oxygen species (ROS) inside the cells which is essential for cell death was detected by staining the cells with 2',7'-Dichlorofluorescin diacetate which turns to green colour in response to oxidative metabolism by esterification reaction. Protamine increased ROS production in Candida cells. These results suggested that protamine could be a lead compound for preparation of biomaterials for anticandidal treatment.

microbiology↗

bioRxiv2024

Anti-Candida and antibiofilm activity of epinecidin-1 and its variants

To boost the stability and antimicrobial efficacy of the antimicrobial peptide (AMP) epinecidin-1, we previously engineered two variants -- variant-1 and variant-2--by substituting alanine and histidine residues with lysine. This modification led to improved structural integrity and antibacterial function. Our current study builds on this foundation by assessing the anti-Candida capabilities of epinecidin-1 and its variants against test organisms Candida albicans, Candida tropicalis, and Candida krusei. Both variants exhibited potent anti-Candida activity, particularly in disrupting biofilm formation. Minimum Inhibitory Concentrations (MICs) were found to be decreased for both variants compared to the original epinecidin-1 peptide, with variant-2 exhibiting the strongest activity. Electron microscopy confirmed that the mechanism of action involves pore formation and the induction of reactive oxygen species in the Candida cell membrane. Computational analysis showed the peptides have a high tendency to interact with the Candida cell membrane proteins like Exo-B-(1,3)-Glucanase, Secreted aspartic proteinase (Sap) 1, and N-terminal domain adhesin: Als 9-2, to prevent biofilm development.

bioengineering↗

bioRxiv2021

Deciphering Multi-way Interactions in the Human Genome

Chromatin architecture, a key regulator of gene expression, can be inferred using chromatin contact data from chromosome conformation capture, or Hi-C. However, classical Hi-C does not preserve multi-way contacts. Here we use long sequencing reads to map genome-wide multi-way contacts and investigate higher order chromatin organization in the human genome. We use hypergraph theory for data representation and analysis, and quantify higher order structures in neonatal fibroblasts, biopsied adult fibroblasts, and B lymphocytes. By integrating multi-way contacts with chromatin accessibility, gene expression, and transcription factor binding, we introduce a data-driven method to identify cell type-specific transcription clusters. We provide transcription factor-mediated functional building blocks for cell identity that serve as a global signature for cell types.

bioinformatics↗

bioRxiv2020

KMT2D Links TGF-β Signalling to Non-Canonical Activin Pathway and Regulates Pancreatic Cancer Cell Plasticity

Although KMT2D, also known as MLL2, is known to play an essential role in development, differentiation, and tumor suppression, its role in pancreatic cancer development is not well understood. Here, we discovered a novel signaling axis mediated by KMT2D, which links TGF-{beta} to the activin A pathway. We found that TGF-{beta} upregulates a microRNA, miR-147b, which in turn leads to post-transcriptional silencing of KMT2D. Loss of KMT2D induces the expression and secretion of activin A, which activates a non-canonical p38 MAPK-mediated pathway to modulate cancer cell plasticity, promote a mesenchymal phenotype, and enhance tumor invasion and metastasis in mice. We observed a decreased KMT2D expression in human primary and metastatic pancreatic cancer. Furthermore, inhibition or knockdown of activin A reversed the pro-tumoral role of KMT2D. These findings reveal a tumor-suppressive role of KMT2D and identify miR-147b and activin A as novel therapeutic targets in pancreatic cancer.

cancer biology↗