Biology subjects

Singha, B.

Publications and source records attributed to Singha, B..

3 recordsLinked to original sources

bioRxiv2024

Association of diet and inflammation with the vaginal microbiota of pregnant individuals with or without IBD

Background and aimsVaginal dysbiosis has been associated with adverse pregnancy outcomes. Here, we characterized the vaginal microbiota of pregnant individuals with inflammatory bowel disease (IBD) and investigated whether gut or vaginal inflammation and diet influence the vaginal microbiota diversity of these individuals. Study DesignWe recruited 48 individuals in their third trimester of pregnancy (IBD=23 and HC=18). We characterized the vaginal microbiota by 16S rRNA sequencing and the gut microbiota by shotgun sequencing. We measured fecal calprotectin in stool and pro-inflammatory cytokines in vaginal fluids. We determine dietary quality using validated 24-hour dietary recalls. ResultsPregnant individuals with IBD exhibit higher levels of fecal calprotectin and increased expression of Th17 pro-inflammatory cytokines (i.e., IL-6, IL-8, IL-17) in the vaginal mucosa compared to healthy pregnant individuals. High fecal calprotectin correlated with high vaginal microbiota diversity. Also, IL-4 (reduced in IBD) was associated with vaginal microbial composition. Regardless of IBD status, pregnant individuals with healthier diets and particularly optimal servings of vegetables and sugars exhibited a vaginal microbiota dominated by Lactobacillus crispatus, a species associated with a lower risk of preterm birth and bacterial vaginosis. ConclusionBesides gut inflammation, pregnant individuals with IBD also exhibit a Th17 immune tone in the vaginal mucosa. The vaginal microbiota diversity or composition, particularly high in the beneficial L. crispatus, is positively associated with healthier diets, regardless of IBD status. Why was the study conducted?An altered vaginal microbiota has been implicated in preterm birth. There is no research on the vaginal microbiome and the factors that influence it in pregnant individuals with Inflammatory Bowel Disease (IBD) at a higher risk of preterm delivery. Key findingsPregnant individuals with IBD exhibit a comparable vaginal microbiome to healthy pregnant individuals. However, pregnant individuals with IBD present a vaginal immune profile characterized by increased levels of Th17 pro-inflammatory cytokines. High dietary quality, and optimal consumption of vegetables and added sugars were associated with vaginal dominance by the beneficial L. crispatus. What does this add to what is known?Our results indicate that the vaginal immune environment and not the microbiome might explain poor pregnancy outcomes for individuals with IBD. Moreover, our study supports the importance of diet to favor L. crispatus, a bacterium associated with a lower risk of preterm birth.

microbiology↗

bioRxiv2023

Divergent downstream biosynthetic pathways are supported by L-cysteine synthases of Mycobacterium tuberculosis

Mycobacterium tuberculosiss (Mtb) autarkic lifestyle within the host involves rewiring its transcriptional networks to combat host-induced stresses. With the help of RNA-seq performed under various stress conditions, we identified that genes belonging to Mtb sulfur metabolism pathways are significantly upregulated during oxidative stress. Using an integrated approach of microbial genetics, transcriptomics, metabolomics, animal experiments, chemical inhibition, and rescue studies, we investigated the biological role of non-canonical L-cysteine synthases, CysM and CysK2. While transcriptome signatures of Rv{Delta}cysM and Rv{Delta}cysK2 appear similar under regular growth conditions, we observed unique transcriptional signatures when subjected to oxidative stress. We followed pool size and labelling (34S) of key downstream metabolites, viz. mycothiol and ergothioneine, to monitor L-cysteine biosynthesis and utilization. This revealed the significant role of distinct L-cysteine biosynthetic routes on redox stress and homeostasis. CysM and CysK2 independently facilitate Mtb survival by alleviating host-induced redox stress, suggesting they are not fully redundant during infection. With the help of genetic mutants and chemical inhibitors, we show that CysM and CysK2 serve as unique, attractive targets for adjunct therapy to combat mycobacterial infection.

microbiology↗

bioRxiv2017

A persistent lack of International representation on editorial boards in biology

The scholars comprising journal editorial boards play a critical role in defining the trajectory of knowledge in their field. Nevertheless, studies of editorial board composition remain rare, especially those focusing on journals publishing research in the increasingly globalized fields of science, technology, engineering, and math (STEM). Using metrics for quantifying the diversity of ecological communities, we quantified international representation on the 1985-2014 editorial boards of twenty-four environmental biology journals. Over the course of three decades there were 3831 unique scientists based in 70 countries that served as editors. The size of the editorial community increased over time - there were 420% more editors serving in 2014 than in 1985 - as did the number of countries in which editors were based. Nevertheless, editors based outside the Global North (the group of economically developed countries with high per capita Gross Domestic Product (GDP) that collectively concentrate most global wealth) were extremely rare. Furthermore, 67.06% of all editors were based in either the USA or UK. Consequently, Geographic Diversity - already low in 1985 - remained unchanged through 2014. We argue that this limited geographic diversity can detrimentally affect the creativity of scholarship published in journals, the progress and direction of research, the composition of the STEM workforce, and the development of science in Latin America, Africa, the Middle East, and much of Asia (i.e., the Global South).

scientific communication and education↗