A combined metagenome and disease enrichment analysis of nitrosamines present in smokeless tobacco, wiz using molecular docking and functional annotation approach

Abstract

Smokeless tobacco products (SLTs) are a major concern due to the associated health risks of the carcinogens, toxins, dynamic microbial system and other harmful chemicals present in them. Procured tobacco leaves are sweetened, flavored and processed to yield the various noncombustible forms of SLTs. These SLTs contain a discrete microbial ecosystem which may contribute to the formation of tobacco specific nitrosamines (TSNAs), endotoxins and other pro inflammatory components. In the present study Whole Metagenome Sequencing was carried out for the exploration of microbial communities followed by their functional profiling. In addition to this, novel targets for TSNAs were predicted using the Swiss Target Prediction tool. Further, disease enrichment analysis of various TSNAs present in Wiz was done using Molecular Docking and functional annotation approach using David database. Bacterial, fungal and viral species were found in the sample where more than 50 % of total bacterial species were Proteobacteria followed by Actinobacteria, Firmicutes, Apicomplexa, Bacteroidetes, Basidiomycota and Cyanobacteria phyla. Total 22,766 genes with 64.9 % GC content were found, which were associated with nitrogen metabolism, antibiotic resistance, multidrug transportation, multitoxins, and pro-inflammation. The presence of phages in wiz showed the possibility of horizontal gene transfer. The pathway enrichment analysis of various TSNAs of wiz were found to be associated with numerous diseases, such as Parkinson's disease, schizophrenia, mental depression, Hypertension, male infertility, Acute Kidney disease and various kinds of cancers.This study will help to understand the possible role of microbiota, TSNAs and their genetic contribution to the overall product's effect on human health. The raw data was submitted to NCBI Short Read Archive (SRA) under Bio Project accession number PRJNA837388.