The general features of the shift to a dormant state in mycobacterial species include several phenotypic changes, reduced metabolic activities, and increased resistance to host and environmental stress conditions. In this study, we aimed to provide novel insights into the viability state and morphological changes in dormant M. smegmatis that contribute to its long-term survival under starvation or hypoxia. To this end, we conducted assays to evaluate cell viability, morphological changes and gene expression. During starvation, M. smegmatis exhibited a reduction in cell length, the presence of viable but non-culturable (VBNC) cells and the formation of anucleated small cells, potentially due to a phenomenon known as reductive cell division. Under hypoxia, a novel population of pleomorphic mycobacteria with a rough surface before the cells reached nonreplicating persistence 1 (NRP1) was identified. This population exhibited VBNC-like behaviour, with a loss of cell wall rigidity and the presence of lipid-body-like structures. Based on dosR and hspX expression, we suggest that M. smegmatis encounters reductive stress conditions during starvation, while lipid storage may induce oxidative stress during hypoxia. These insights into the heterogeneous populations presented here could offer valuable opportunities for developing new therapeutic strategies to control dormant mycobacterial populations.

Background: Severe obesity is associated with metabolic alterations and an increased risk of developing type 2 diabetes. Bariatric surgery, especially malabsorptive procedures, results in significant clinical improvements and induces changes in the gut microbiota composition. This study aimed to identify bacterial taxa associated with changes in body mass index (BMI) in patients undergoing bariatric surgery and to explore their relationship with nutrient intake. Methods: Individuals with severe obesity were recruited prior to and following bariatric surgery. Fecal DNA was extracted and the V4 region of the 16S rRNA gene was sequenced. Quality control and taxonomic classification were performed using QIIME2 and the Greengenes database. Nutrient intake was assessed through a 7-day dietary recall. Anthropometric measurements and blood samples were collected to evaluate clinical variables. Statistical analyses were conducted using R software. Results: Significant differences in gut microbiota diversity were observed post-bariatric surgery. The Shannon and Simpson diversity indices decreased significantly after surgery (p < 0.001). Beta diversity analysis (Bray-Curtis, Weighted and Unweighted UniFrac) also showed significant differences between pre- and post-surgery samples (p = 0.001). The abundance of a species within the genus Coprococcus was positively correlated with magnesium and thiamin intake in post-surgery patients (rho = 0.816, p _FDR = 0.029 and rho = 0.812, p _FDR = 0.029, respectively). Furthermore, Coprococcus sp. abundance was positive associated with BMI in pre-surgery individuals (p = 0.043) but negative associated with BMI in post-surgery individuals (p = 0.036). Several taxa within the order Clostridiales and microbial metabolic pathways involved in sugar degradation, acetate, thiamin (vitamin B1) and some amino acid production were enriched prior to surgery. Conclusions: The abundance of a species of the genus Coprococcus showed an inverse relationship with BMI in pre-surgery and post-surgery individuals and correlated positively with magnesium and thiamin intake in patients who underwent a malabsorptive bariatric surgery. These findings suggest that optimizing micronutrient intake may enhance the beneficial effects of bariatric surgery on BMI by favorably modulating gut microbiota composition.

Background: Morbid obesity is associated with metabolic alterations and the onset of type 2 diabetes. Patients who undergo a malabsorptive bariatric surgery show an important improvement in several clinical variables and a modification in the gut microbiota balance. In this study, we aimed to identify bacteria related to changes in the body mass index of patients who underwent a bariatric surgery and their relationship with nutrients intake. Results: There were differences in bacterial diversity in the gut microbiota of patients that underwent a bariatric surgery. The Shannon and Simpson indexes decrease after the surgery (p < 0.001) and the beta diversity indexes (Bray-Curtis, Weighted and Unweighted UniFrac) showed differences when comparing pre- and post-surgery (p = 0.001). The abundance of a species in the genus Coprococcus correlated positively with the intake of magnesium and thiamin in post-surgery individuals (rho = 0.816, pFDR = 0.029 and rho = 0.812, pFDR = 0.029, respectively) and was related to BMI in both groups (p = 0.043 pre-surgery and p = 0.036 post-surgery). The abundances of several bacteria belonging to the order Clostridiales, as well as an enrichment of vitamin B1 (thiamin) biosynthesis, sugar degradation, acetate production and some amino acids biosynthesis were higher before the surgery. Conclusions: The abundance of a species of the genus Coprococcus that showed inverse relationships with BMI in pre-surgery and post-surgery patients correlates with the intake of magnesium and thiamin in individuals that underwent a malabsorptive bariatric surgery. It indicates that the well-established beneficial effects of bariatric surgery on BMI may be amplified by modulating the intake of micronutrients and its effect on the gut bacterial.

Coffee is one of the most widely consumed beverages worldwide. Coffee and its bioactive compounds, including caffeine, chlorogenic acid, and caffeic acid, have received increasing attention due to their potential contribution to coffee-associated health benefits. Evidence from pediatric and adult populations supports a positive association between fructose intake from sugar-sweetened beverages and the increasing prevalence of obesity and other non-communicable diseases. In this context, coffee consumption may represent a potential protective dietary factor against high fructose intake-induced metabolic alterations, including obesity, type 2 diabetes, liver disease, cardiovascular disease, and alterations in gut microbiota composition. However, human evidence on the effects of coffee consumption on fructose-related metabolic alterations remains limited, making it difficult to determine whether the benefits observed in animal models translate to humans. Therefore, this review summarizes current evidence on the potential role of coffee consumption and coffee-derived bioactive compounds in modulating fructose-induced metabolic alterations and discusses the mechanisms involved.

Coffee is one of the most widely consumed beverages worldwide. Coffee and its bioactive compounds, including caffeine, chlorogenic acid, and caffeic acid, have attracted increasing attention because of their potential health benefits. Evidence from pediatric and adult populations supports a positive association between fructose intake from sugar-sweetened beverages and the increasing prevalence of obesity and other non-communicable diseases. In this context, coffee consumption may represent a potential protective dietary factor against high fructose intake-induced metabolic alterations, including obesity, type 2 diabetes, liver disease, cardiovascular disease, and alterations in gut microbiota composition. Therefore, this review summarizes current evidence on the potential role of coffee consumption and coffee-derived bioactive compounds in modulating fructose-induced metabolic alterations and discusses the mechanisms involved. However, current evidence from human studies remains limited, and the clinical relevance of the beneficial effects observed in experimental models requires confirmation through well-designed clinical trials.