Uncovering the antimicrobial activity of G-type lysozyme 2 derived from Cyprinus carpio mucus against bacterial and fungal pathogens.

This study aimed to explore the antimicrobic potential of mucus samples collected from Cyprinus carpio and identify the specific antimicrobial peptides responsible for its activity. The crude extract was tested against various bacterial and fungal pathogens, and its protein content and profile were analyzed. Purification steps, including gel filtration chromatography, were employed to isolate the most active fraction (peak IV), which was further identified via liquid chromatography and mass spectroscopy. The results revealed varying degrees of antimicrobial activity of the crude extract against different bacterial and fungal strains, with Leclercia adecarboxylata, Candida glabrata, and Candida parapsilosis showing the highest susceptibility. SDS-PAGE analysis demonstrated the existence of multiple low molecular weight protein bands in the crude extract, while fraction IV obtained from gel filtration chromatography exhibited the strongest antimicrobial activity. Peak IV displayed a range of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values against the tested pathogens, spanning from 0.038 to 4.960 mg/mL. Further investigation identified the purified peptide derived from peak IV as G-type lysozyme 2, characterized by a molecular weight of 21 kDa. These findings shed light on the existence of a highly effective antimicrobial peptide, G-type lysozyme 2, within the mucus of Cyprinus carpio. This peptide demonstrates notable activity against diverse bacterial and fungal pathogens. The insights from this study enhance our understanding of the fish's antimicrobial defense mechanisms and hold promise for developing novel antimicrobial agents.

The hidden world of fish fungal pathogens: molecular identification and phylogenetic analysis in common carp, Cyprinus carpio.

Fungal infections pose a significant threat to aquaculture, causing substantial economic losses and ecological disruptions. The common carp (Cyprinus carpio), as a crucial farmed fish, requires in-depth research to uncover the underlying fungal pathogens affecting its health. In this study, we analyzed 150 samples of C. carpio to identify the fungal pathogens responsible for the infections based on clinical signs and symptoms. Further, we assessed fungal diversity and prevalence in the infected fish. The infected fish exhibited varying degrees of gross pathogenicity, with fins and skin heavily affected, intermediate infection observed in the head and gills, and the least infection found in the operculum. Morphological examination revealed distinct characteristics such as necrosis, lesions on the skin, fins, and gills, as well as loss of scales, hemorrhagic lesions, and red spots. Furthermore, the presence of gray and white cottony patches on the body confirmed ascomycete and zygomycete infections, while a dark white cottony mass indicated phycomycete infection. Some fish exhibited severe fungal infections, presenting prominently curved spines and necrosis with red spots on the skin. These isolates belonged to various fungal groups, including ascomycetes, zygomycetes, phycomycetes, deuteromycetes, and basidiomycetes. Among these, Fusarium oxysporum emerged as the most prevalent fungal pathogen, followed by Fusarium solani, Saprolegnia delica, and Saprolegnia parasitica. Molecular identification based on ITS and LSU rRNA sequences confirmed the presence of Saprolegnia delica, Mucor hiemalis, Coniothyrium telephii, Rhodotorula mucilaginosa, Penicillium cellarum, and Fusarium californicum in the fish samples. Phylogenetic analysis further supported the morphological and molecular data, providing insights into the relationship between the isolated fungal strains and known species from various geographical regions. Our study enhances our understanding of the diversity and prevalence of fish fungal pathogens in common carp, emphasizing the significance of employing molecular techniques for accurate identification. These comprehensive findings offer essential insights into the impact of fungal infections on common carp populations, laying the groundwork for targeted control measures to mitigate their effects on global aquaculture.

A report on the incidence of Trichodina heterodentata from fishes of Jammu, J&K India.

The present study was aimed at screening for the presence of protozoan's among Cyprinid fishes collected from various fish ponds and farms in Jammu division of Jammu and Kashmir (J and K) state. Out of 75 fishes collected from local water bodies of Jammu division, only 35, (49.6 %) were infested with Trichodina. Trichodina infestations were studied in the period from November to February. In light infestation Trichodina was usually present on gills, fins and skin of apparently healthy fish. Clinical signs of Trichodiniasis appeared on fish with heavy infections and in presence of one or more stress factors including, rough handling during transportation from ponds, over crowdedness, malnutrition, high concentration of free ammonia and low oxygen concentration. Clinical signs of Trichodiniasis in fish such as sluggish movement, loss of appetite, black colouration, necrosis and ulcer on different parts of the body, detached scales and excessive accumulation of mucous in gill pouches were also observed.