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bioRxiv2023

Assessment of genetic diversity patterns of different serotypes of dengue virus, prevalent in patients from Kerala, India: a strain specific mutation study and its relevance to pathogenesis

The mutations are the key mechanisms responsible for virus survival and its fitness in the host. This process of mutation is implicated in the development of pathogenesis of the dengue viral disease. We report that, all the four serotypes were found to be circulating in Kerala sate of India. Serotypes 1 and 3 were the predominant type (33.3 %) compared to others. The prevalence of co-infection of serotype 1 and 4 was the highest percentage (11.1 %) compared to serotype 2 and serotype 3 (5.5 %). We further highlighted the immunopathological mechanisms of antibody neutralization, CD4+ T cell response and antibody dependent enhancements (ADE) for the possible cause of disease severity in coinfections. Serotype-1 does not show much variations from the previously reported strains from various regions of India. However, serotype-2 showed variations in the sequences from the other strains of serotype-2 previously reported from various regions of India and formed a distinct clade in the genotype-4. Serotype-3 and serotype-4 showed similarity with previously reported strains from India. Moreover, serotype-1 was grouping in genotype-5. Importantly, the serotype-2 grouped with genoptype-4 but exist separately. Serotype-3 was found to be grouped with the genotype-3. The serotype-4 show the very much similarities from the genotype-1 and shows little difference from the previously reported strains from India. Further, mutation in DENV-3 sequences, at position 235 (C to T) and 322 (G to T) shows an important phenomenon which might be adopted by the virus to survive. As severe dengue is linked with the serotype-2, the genetic variations in this serotype points towards the much specific strategy to be adopted in near future to manage the severe dengue disease. In conclusion, we can say that, genetic diversity in the CprM region is present in the different serotypes circulating in the patients from Kerala India and this information may help in the management of dengue viral disease.

immunology↗

bioRxiv2021

Effect of Aeromonas hydrophila infected on metabolomic response and gut microbial 16S rRna of Charybdis japonica

The innate immune response of Charybdis japonica treated with Aeromonas hydrophila was explored using bioinformatics. Metabolomics data were integrated with a gut microbial 16S rRNA dataset, together with information on corresponding enzyme activity. The results of the study showed that after being infected with A. hydrophila, some beneficial genera of bacteria in the gut of C. japonica, such as Photobacterium, Rhodobacter, Polaribacter, Psychrilyobacter, Mesoflavibacter, Fusibacter and Phormidium, could directly inhibit Vibrio or produce extracellular polysaccharides with highly effective antibacterial properties. The intestinal probiotics of C. japonica such as Mesoflavibacter have a mutually reinforcing relationship with Phaeobacter, Colwellia, Bacillus, Psychrobacter and Cohaesibacter. Conditional pathogenic bacteria in the gut of healthy crabs may also have such a symbiotic relationship with intestinal probiotics, promoting their growth and reproduction. For example, Phormidium has a mutualistic relationship with Aeromonas and Azopira. Metabolites in the gut of C. japonica infected with A. hydrophila, including beta-alanine metabolism, nitrogen metabolism, inositol phosphate metabolism, galactose metabolism, histidine metabolism, ascorbate and arginine and proline metabolism were increased, with alanine metabolism being the most abundant. The activity of metabolite related enzymes such as lipid peroxidase, phenoloxidase, superoxide dismutase, nitric oxide synthase, glutathione transferase and mid-glutathione decreased and NO levels also decreased. The positive correlation with the probiotic flora suggests that metabolites increase with bacterial abundance and that microbial metabolites or co-metabolites can, in turn, achieve many pleiotropic effects to resist invasion by A. hydrophila. These results may contribute to further research in the resistance of C. japonica to invading pathogens. ImportanceWith the rapid development of the C. japonica farming industry, investors, in pursuit of economic benefits, have encountered problems such as frequent outbreaks of various diseases, resulting in high mortality and huge economic losses. The open water circulation system can give rise to several crab bacterial diseases. Among these, A. hydrophila is a pathogenic bacterium affecting fish and crustaceans, which leads to huge economic losses. Our results suggest that metabolites increased with the abundance of bacteria. It is possible that the autoimmune system and the entry of A. hydrophila into the intestinal tissues of C. japonica react immunologically and that the organism is producing certain metabolites which may be metabolised by various bacteria and absorbed into the circulation. In addition, some of these metabolites are modified or bound in the hepatopancreas to produce microbiota-host co-metabolites. These microbial metabolites or co-metabolites can resist invasion by A. hydrophila.

immunology↗