Sep 2026· Comparative biochemistry and physiology. Toxicology & pharmacology : CBP· Vol 307, pp.
110582
· 0 citations· 56 references
Medicine
TL;DR
This study provides the first comparative transcriptomic, structural, and functional characterization of AMPs and anti-microbial proteins in N. quadripunctatus and N. littoralis, offering important foundational insights for the future development of bacteria-specific AMPs as alternatives to conventional antibiotics.
Abstract
To identify the differential properties of anti-microbial peptides (AMPs) and proteins in the burying beetle Nicrophorus quadripunctatus and the short sexton beetle Necrodes littoralis, we performed comparative transcriptomic analyses, quantified gene expression levels, examined structural variations, and evaluated anti-microbial and hemolytic activities of representative AMPs, including cecropin B and defensin. Two AMPs (cecropin B and defensin) and four anti-microbial proteins (cathelicidin, lysozyme, major royal jelly protein, and peptidoglycan recognition proteins) were predominantly detected. Defensin was the most highly expressed AMP in both species, whereas cecropin B showed relatively lower expression. Cecropin B and defensin in N. quadripunctatus exhibited 52.2- and 100.9-fold higher relative transcription levels, respectively, compared with N. littoralis, representing the two largest expression differences among the examined genes. Notably, substantial sequence variation was observed in the mature peptide regions of both AMPs between the two species. The α-helices of both AMPs from N. quadripunctatus exhibited longer segments than those from N. littoralis as a structural feature. Defensin of N. littoralis exhibited significantly higher anti-microbial activity against Gram-positive bacteria compared with that of N. quadripunctatus. In addition, only cecropin B exhibited anti-microbial activity against Gram-negative bacteria, and neither of the two AMPs showed detectable hemolytic activity. Overall, this study provides the first comparative transcriptomic, structural, and functional characterization of AMPs and anti-microbial proteins in N. quadripunctatus and N. littoralis, offering important foundational insights for the future development of bacteria-specific AMPs as alternatives to conventional antibiotics.
A novel piscidin was identified in largemouth bass that contained an active peptide of 25 aa with an amphipathic helix possessing distinct hydrophobic and positively charged regions, and was significantly up-regulated in spleen from 6 h to 24 h post-lipopolysaccharide (LPS) stimulation.
J. Tian, Liqiang Zhang, Qihuan Zhang et al.· Fishes· 0 citations
Eucalyptus bacterial wilt in China, caused predominantly by Ralstonia pseudosolanacearum, severely threatens Eucalyptus plantation management in China and demands plant-derived alternatives to conventional bactericides. This study evaluated the in vitro antibacterial activities and underlying molecular mechanisms of two differentially substituted coumarin derivatives, daphnetin (DAP) and 6-methylcoumarin (MC), against a eucalyptus-derived R. pseudosolanacearum strain. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using broth microdilution assays. Quantitative phenotypic assays were conducted to evaluate the effects of sub-lethal concentrations on biofilm formation, swimming motility, and extracellular polysaccharide (EPS) accumulation. Furthermore, high-throughput RNA sequencing integrated with GO and KEGG enrichment analyses was employed to characterize the genome-wide transcriptomic responses. Antimicrobial susceptibility testing demonstrated that DAP possessed superior bactericidal efficacy, yielding lower MIC (62.5 μg/mL) and MBC (250 μg/mL) values than MC. Conversely, sub-lethal MC exhibited a more pronounced, early-stage suppression of flagellum-dependent swimming motility and biofilm maturation. Both compounds consistently attenuated EPS production. Transcriptomic analysis revealed distinct yet partially convergent regulatory networks: DAP primarily exerted metabolic strangulation by downregulating genes governing aerobic respiratory chains and peripheral carbon/nitrogen pathways, whereas MC targeted collective behavior and active pathogenesis, systematically downregulating the expression of genes associated with flagellar assembly, quorum sensing, and Type III and VI secretion systems. Notably, both pathways converged downstream to repress the master virulence regulator xpsR and the epsA-P operon. These findings provide valuable insights into the potential molecular pathways affected by DAP and MC, offering a useful reference for future exploration of botanical formulations for ecologically responsible forest disease control.
H. Xue, N. Jiang, Yong Li· Microorganisms· 0 citations
It is demonstrated that Pelamoviroid latenspruni can persist latently in medlar while exerting measurable effects on fruit quality, highlighting the importance of considering latent viroid infections in fruit crop management and certification systems, as asymptomatic infections.
H. Oksal, Mert Baran, Şevval Adigüzel et al.· Journal of plant diseases an...· 0 citations
Piscidins are cationic α-helical antimicrobial peptides (AMPs) that constitute a key component of the innate immune defense of teleost fish, yet the relationship between their genomic organization, structural properties, and functional specialization remains incompletely understood. In this study, six piscidin peptides from Epinephelus akaara, Seriola dumerili, Thunnus maccoyii, Argyrosomus regius, Dicentrarchus labrax, and Epinephelus coioides were characterized through an integrated sequence-to-function approach combining comparative genomics, structural modeling, physicochemical analysis, and in vitro validation, with the aim of identifying candidates with potential for biomedical and biotechnological applications. All genes studied exhibited the conserved four-exon, three-intron architecture characteristic of teleost piscidins. Structural modeling and circular dichroism confirmed α-helical conformations under membrane-mimetic conditions, despite measurable differences in hydrophobicity, charge distribution, and predicted membrane insertion parameters. Antimicrobial assays revealed distinct functional profiles: Sd_FI25 and Epinecidin_1 displayed broad antibacterial activity against Gram-positive and Gram-negative pathogens, whereas Dl_FI22 showed selective activity with reduced temporal persistence associated with lower peptide stability. Ea_FF25 exhibited comparatively weak antibacterial potency. Antibiofilm activity varied among peptides and did not uniformly parallel planktonic MIC values. Computational predictions further suggested antiviral and antitumoral potential for several sequences, extending their prospective relevance beyond classical antibacterial roles. Conserved genomic architecture and α-helical structure coexist with pronounced functional diversification among teleost piscidins. These findings demonstrate that integrating structural prediction with experimental validation is an effective strategy for identifying fish-derived innate immune peptides as candidates for biomedical applications.
Patricia Asensio-Calavia, Sergio González-Acosta, M. Cavaco et al.· Fish and Shellfish Immunolog...· 0 citations
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