The microbiota that resides in the gastrointestinal tract provides essential health benefits to the host. In particular, they regulate immune homeostasis. Recently, several evidences indicate that alteration in the gut microbial community can cause infectious and non-infectious diseases. Tuberculosis (TB) is the most devastating disease, inflicting mortality and morbidity. It remains unexplored, whether changes in the gut microbiota can provoke or prevent TB. In the current study, we have demonstrated the antibiotics driven changes in the gut microbial composition and their impact on the survival of Mycobacterium tuberculosis (Mtb) in the lungs, liver, and spleen of infected mice, compared to those with intact microbiota. Interestingly, dysbiosis of microbes showed significant increase in the bacterial burden in lungs and dissemination of Mtb to spleen and liver. Furthermore, elevation in the number of Tregs and decline in the pool of IFN-γ- and TNF-α-releasing CD4 T cells was noticed. Interestingly, fecal transplantation in the gut microbiota disrupted animals exhibited improved Th1 immunity and lesser Tregs population. Importantly, these animals displayed reduced severity to Mtb infection. This study for the first time demonstrated the novel role of gut microbes in the susceptibility to TB and its prevention by microbial implants. In future, microbial therapies may help in treating patients suffering from TB.

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Bacillus is an important genus as it is a source for antibiotics, enzymes, and probiotics. Therefore, several studies are targeted on this genus in order to understand its diversity abundance in different soil environments. In present study, we investigated the diversity of Bacillus at species level using culturable approach in soils collected at different climatic zones of India and identified 20 prominent members of genus Bacillus species that are able to grow in different media types under same culture conditions. Results also showed that the species diversity of Bacillus changes according to the soil microenvironment under the influence of different climatic conditions. As a pilot study using culturable approach, we made an attempt to investigate the shift in Bacillus species diversity present in the Indian soils experiencing a climatic gradient over a large geographic area.

Tuberculosis continues to be one of the most devastating global health problem. Its diagnosis will benefit in timely initiation of the treatment, cure and therefore reduction in the transmission of the disease. Tests are available, but none can be comprehensively relied on for its diagnosis; especially in TB-endemic zones. PhoP is a key player in Mycobacterium tuberculosis virulence but nothing has been known about its role in the diagnosis of TB. We monitored the presence of anti-PhoP antibodies in the healthy, patients and their contacts. In addition, we also measured antibodies against early secretory antigens ESAT-6 and CFP-10, and latency associated antigen Acr-1 to include proteins that are associated with the different stages of disease progression. Healthy subjects showed high antibody titer against PhoP than patients and their contacts. In addition, a distinct pattern in the ratio of Acr-1/PhoP was observed among all cohorts. This study for the first time demonstrates a novel role of anti-PhoP antibodies, as a possible marker for the diagnosis of TB and therefore will contribute in the appropriate action and management of the disease.

α-amylases (EC3.2.1.1) are glycoside hydrolases that breakdown complex starch and maltodextrins into glucose and maltose by acting upon 1,4-glycosidiclinkages. Several amylases have been isolated and purified from members of Bacillus community, which find extensive application in starch processing, textile and pharmaceutical industry. Keeping this in mind we isolated α-amylase producing gram positive bacterium from soils collected from mountain climatic zone of India and identified it as Brevibacillus laterosporus. We further studied the effect of temperature and pH on the amylase activity of this strain and found a very stable activity at alkaline pH of 10 and temperature of 45 ºC. To our knowledge this a first report on characterization and evolutionary analysis of alkaline α-amylase producing Brevibacillus laterosporus isolated from unexplored sites of mountain climatic zone of India. Keywords: Climatic zone, Brevibacillus, Amylase, 16S rRNA gene sequencing, Phylogenetic analysis

Background: The multidirectional relationship between soil, its microbiota, and climate is crucial in modulating the bacterial community diversity and its survival in the terrestrial ecosystem. Therefore, it is imperative to understand the dynamics of soil bacterial communities thriving in geographical areas of varied climatic exposure. Results: The diversity of terrestrial soil bacterial communities thriving in four contrasting Köppen climatic zones of India was investigated for the first time using high-throughput sequencing. The results revealed that the bacterial species diversity, evenness and richness were highest in HSCZ (humid subtropical climatic zone). Firmicutes was the most abundant phylum in TWCZ (tropical wet climatic zone), ACZ (arid climatic zone), and HSCZ (humid subtropical climatic zone) while Proteobacteria in MCZ (Mountain climatic zone). The predominance of class Alphaproteobacteria, Actinobacteria with genera Bradyrhizobium, Chthoniobacter, and Mycobacterium, was observed in MCZ in contrast to class Bacilli with genera Bacillus and Paenibacillus in the rest of the zones. Correlation analysis showed that H’ (Shannon diversity) index, S (species richness), OTU abundance were positively correlated with moisture, TOC, K, MAP (mean annual precipitation) and negatively correlated with pH, Ca, N, B. Fe, P, Mg and MAT (mean annual temperature). Conclusion: This work mapped the occurrence and distribution of terrestrial soil bacterial communities in contrasting climatic zones that enabled us to assess the effect of climate in mentioned Köppen climatic zones on a taxonomic scale.