Strategies for describing myxozoan pathogens, dreadful fish diseases in aquaculture.

Myxozoans are obligate endoparasites, cosmopolitan in distribution with both vertebrate and invertebrate hosts. Their myxospores consist of shell valves, polar capsules with coiled polar tubules that are extrudible, and infective amoeboid germs. Myxozoan parasites are most abundant, and due to their increasing number in recent years, they can pose an emerging threat to the fish industry worldwide. Hence, the immediate need is to devise a strategy to understand and detect parasites and parasitism. They may proliferate to different organs with the advancement of infection. This all warrants the development/devising of strategies and results of integrative studies in order to identify these dreadful parasites and resolve taxonomic issues. Different methods whether classical methods including gross morphology or advanced methods such as electron microscopy (SEM, TEM, STEM), Confocal laser scanning microscopy (CLSM), histopathological studies, site preference, host and tissue specificity, a molecular approach using new markers can be clubbed for identification because these parasites are hidden and are difficult to recognize. This group was earlier classified only on the basis of myxospores morphology, but due to the high structural variability of this group advanced methods and approaches have to be implied which can minimize the problems in assigning new species.

Molecular characterization of fungal endophyte diversity isolated from Aconitum heterophyllum: a critically endangered medicinal plant of Kashmir Himalaya / Caracterización molecular de la diversidad de endófitos fúngicos aislados de Aconitum heterophyllum: una planta medicinal en peligro crítico del Himalaya de Cachemira

Aconitum heterophyllum is a rare perennial herb from Kashmir Himalayas. Due to its threatened status and dependence on its environment, the plant was examined for any potential endophytes, which is of utmost importance for bioprospection. In the current study, endophytic fungal diversity associated with A. heterophyllum was examined, and 328 fungal isolates were found in the plant’s leaf, stem, and root tissues. Twelve (12) endophytic fungal species were identified utilizing, molecular analysis of the nuclear ribosomal DNA Internal Transcribes Spacer (ITS), rLSU, and rSSU sequences. Maximum likelihood analysis was used to determine the phylogenetic connection between each isolate. The genera Arthrinium, Chaetomium, Purpureocillium, Alternaria, Penicillium, Aspergillus, Cladosporium, and Bjerkandera species dominated the ascomycete and basidiomycete fungal endophytes.(AU)

Molecular characterization of fungal endophyte diversity isolated from Aconitum heterophyllum: a critically endangered medicinal plant of Kashmir Himalaya.

Aconitum heterophyllum is a rare perennial herb from Kashmir Himalayas. Due to its threatened status and dependence on its environment, the plant was examined for any potential endophytes, which is of utmost importance for bioprospection. In the current study, endophytic fungal diversity associated with A. heterophyllum was examined, and 328 fungal isolates were found in the plant's leaf, stem, and root tissues. Twelve (12) endophytic fungal species were identified utilizing, molecular analysis of the nuclear ribosomal DNA Internal Transcribes Spacer (ITS), rLSU, and rSSU sequences. Maximum likelihood analysis was used to determine the phylogenetic connection between each isolate. The genera Arthrinium, Chaetomium, Purpureocillium, Alternaria, Penicillium, Aspergillus, Cladosporium, and Bjerkandera species dominated the ascomycete and basidiomycete fungal endophytes.

Evaluation of blood cell viability rate, gene expression, and O-GlcNAcylation profiles as indicative signatures for fungal stimulation of salmonid cell models.

Fungal diseases of fish are a significant economic problem in aquaculture. Using high-throughput expression analysis, we identified potential transcript markers in primary head kidney and secondary embryonic cells from salmonid fish after stimulation with the inactivated fungi Mucor hiemalis and Fusarium aveneacium and with purified fungal molecular patterns. The transcript levels of most of the 45 selected genes were altered in head-kidney cells after 24 h of stimulation with fungal antigens. Stimulation with the inactivated fungus M. hiemalis induced the most pronounced transcriptional changes, including the pathogen receptor-encoding genes CLEC18A and TLR22, the cytokine-encoding genes IL6 and TNF, and the gene encoding the antimicrobial peptide LEAP2. In parallel, we analyzed the total GlcNAcylation status of embryonic salmonid cells with or without stimulation with inactivated fungi. O-GlcNAcylation modulates gene expression, intracellular protein, and signal activity, but we detected no significant differences after a 3-h stimulation. A pathway analysis tool identified the "apoptosis of leukocytes" based on the expression profile 24 h after fungal stimulation. Fluorescence microscopy combined with flow cytometry revealed apoptosis in 50 % of head-kidney leukocytes after 3 h stimulation with M. hiemalis, but this level decreased by > 5% after 24 h of stimulation. The number of apoptotic cells significantly increased in all blood cells after a 3-h stimulation with fungal molecular patterns compared to unstimulated controls. This in vitro approach identified transcript-based parameters that were strongly modulated by fungal infections of salmonid fish.

Study on pathogenicity and characterization of disease causing fungal community associated with cultured fish of Kashmir valley, India.

Cultured fisheries of developing countries are continously challenged by a number of pathogenic microbes. Among microbial diseases, fungal and fungal like pathogen outbreaks lead to negative social and economic impacts on stakeholders. The cultured fisheries of Kashmir valley are also facing challenge from fungal pathogens, leading to tremendous socio-economic lossess to the fish farmer community hence, yearns to boost the sector with efficient management strategy. Our study was aimed at investigating the diversity of fungal communities infecting cultured rainbow trout and carp fish species. We employed classical microbiology, macro and micro morphological characteristics, and molecular analysis (multilocus typing) for fungal identification. Also histopathological approach was used to examine the pathogenicity patterns of diverse fungal groups. The study revealed that the infection in fish was predisposed to both superficial as well as visceral organs. However, skin, gills and head were predominantly infected compared to internal organs. The microbiological investigation of infected fish by culture dependent approach helped us to obtain the total of 250 fungal isolates. Out of these isolates, 21 different species were identified belonging to three diverse fungal groups which mostly included 14 species among Ascomycetes, 03 species of Oomycetes and 04 species of Zygomycetes. The majority of fungi which were infectious to cultured fish of valley are biotrophic or opportunistic soil fungi, and some of them being exclusive pathogens of fish.

Fish antimicrobial peptides (AMP's) as essential and promising molecular therapeutic agents: A review.

Antimicrobial peptides (AMPs) are generally considered as an essential component of innate immunity, thereby providing the first line of defense against wide range of pathogens. In addition, they can also kill the pathogens which are generally resistant to number of antibiotics, thereby providing the avenues for the development of future therapeutic agents. Fishes are constantly challenged by variety of pathogens which not only shows detrimental effect on their health but also increases risk of becoming resistant to conventional antibiotics. As fishes rely more on innate immunity, AMPs can serve as a potential defensive weapons in fishes for combating emerging devastating diseases. Generally, AMPs show multidimensional properties like rapid diffusion to the site of infection, recruitment of other immune cells to infected tissues and vigorous potential to rapidly neutralize broad range of pathogens (bacterial, fungal and viral). AMPs also exhibit diverse biological effect like endotoxin neutralization, immunomodulation and induction of angiogenesis in mammals. Due to these properties AMPs have become one of the most promising therapeutic agents to be studied. Till date, many AMPs have been isolated from the fishes but not fully characterized at molecular level. This review provides an overview of the structures, functions, and putative mechanisms of major families of fish AMPs. Further, we also highlighted how fish AMPs can be used as a novel therapeutic tool which is the theme of future research in drug development.