Biology subjects

Simo, R.

Publications and source records attributed to Simo, R..

3 recordsLinked to original sources

bioRxiv2026

Identification of specific gut bacteria and metabolomic signatures related to Myocardial Insulin Resistance in Type 2 Diabetes

BackgroundIn myocardial insulin resistance (mIR), insulin fails to appropriately stimulate myocardial glucose uptake, which can contribute to the development of heart disease. This reversible metabolic abnormality occurs in only a fraction of patients with type 2 diabetes mellitus (T2DM) and may be present even before clinical symptoms or the onset of diabetes. Identifying biomarkers of early-stage mIR is crucial to halt its progression with appropriate treatment and lifestyle interventions. In this context, we explore, for the first time, specific gut bacteria and fecal and plasma metabolic signatures associated with mIR. MethodsForty-two T2DM patients were divided into two groups, mIR patients patients with myocardial insulin sensitivity (mIS), depending on their myocardial glucose uptake measured with 18F-FDG PET during the hyperglycemic clamp. For each group, fecal microbiota was quantified by Illumina sequencing, and metabolomic profiles in feces and plasma were determined by NMR spectroscopy. ResultsThe Faiths phylogenetic diversity index was reduced significantly in mIR patients, compared with mIS patients. Linear discriminant analysis effect size (LEfSe) analysis revealed 25 bacterial taxa differing between mIS and mIR groups, and 6 bacteria (Thermicanus, Lachnobacterium, Desulfovibrio, Desulfuromusa, Desulfosporosinus and Coprobacillus cateniformis) were significantly decreased in mIR patients at the genus and species levels. Multivariate metabolomic analysis determined that six fecal metabolites (arabinose, {beta}-galactose and ribose, aspartate, histidine and lactate) and six plasma metabolites (creatinine, myo-inositol, threonine, {beta}-galactose, glycerol and choline) were reduced in mIR patients while plasmatic levels of VLDL(CH3) were elevated significantly. Myocardial IR correlated positively with plasmatic VLDL(CH3) and was negatively associated with two bacteria (Desulfosporosinus and Coprobacillus cateniformis), five fecal metabolites (arabinose, {beta}-galactose, ribose, aspartate, and histidine) and two plasma metabolites (choline and {beta}-galactose). ConclusionsOur pilot study proved that the gut microbiome and the metabolic plasma profile is altered in T2DM patients with mIR. Regression analysis and predictive modelling identified the bacteria Desulfosporosinus and the metabolite galactose as key biomarkers, which could aid in the identification of T2DM patients at risk for myocardial IR and in the design of novel therapeutic strategies to prevent it.

microbiology↗

bioRxiv2025

Metagenomic-based network analysis reveals the importance of vitamin cross-feeding in marine microbial assemblages

Vitamins play a fundamental role in microbial metabolism and interactions, yet their scarcity in marine environments and the limited ability for de novo synthesis of some vitamins often leads to metabolic dependencies and cross-feeding among microbial taxa. Using a decade-long time-series metagenomics dataset from the Blanes Bay Microbial Observatory (BBMO), we investigated the role of vitamin biosynthesis in structuring the seasonal marine microbial interactions among prokaryotes and eukaryotes. Gene co-occurrence analysis revealed that vitamin-related metabolism had the highest number of associations among all metabolic pathways, underscoring the potential role of vitamins in microbial interactions. Metagenome-assembled genome (MAG) co-occurrence analysis further identified the prokaryotic biosynthesis of cobalamin (B12) and thiamine (B1) as key mediators of these associations. Rather than between complete vitamin synthesizers and auxotrophs, the main associations were found between partial synthesizers, suggesting that vitamer cross-feeding may represent an essential microbial interaction in sustaining vitamin biosynthesis throughout the year. While complete cobalamin synthesizers dominate in summer, partial synthesizers and lower-ligand activators are more prevalent in winter, driving cross-feeding interactions. In contrast, thiamine biosynthesis is more widespread, with complete synthesizers peaking in winter. The association strength, however, was maximum between prokaryotic vitamin producers and eukaryotes, highlighting the dependence of eukaryotes on bacterial vitamin production. These results provide novel insights into seasonal metabolic interdependencies, emphasizing the ecological significance of vitamin biosynthesis in marine ecosystems.

microbiology↗

bioRxiv2021

Viral infection switches the balance between bacterial and eukaryotic recyclers of organic matter during algal blooms

Algal blooms are hotspots of marine primary production and play central roles in microbial ecology and global nutrient cycling. When blooms collapse, organic carbon is transferred to higher trophic levels, microbial respiration or sinking in proportions that depend on the dominant mortality agent. Viral infection can lead to bloom termination, but its impact on the fate of carbon remains an open question. Here, we characterized the consequences of viral infection on the microbiome composition and biogeochemical landscape of marine ecosystems by conducting a large-scale mesocosm experiment. Moniroting of seven induced coccolithophore blooms, which showed different degrees of viral infection, revealed that only high levels of viral infection caused significant shifts in the composition of free-living bacterial and eukaryotic assemblages. Intriguingly, viral infection favored the growth of eukaryotic heterotrophs (thraustochytrids) over bacteria as potential recyclers of organic matter. By combining modeling and quantification of active viral infection at a single-cell resolution, we estimate that viral infection can increase per-cell rates of extracellular carbon release by 2-4.5 fold. This happened via production of acidic polysaccharides and particulate inorganic carbon, two major contributors to carbon sinking into the deep ocean. These results reveal the impact of viral infection on the fate of carbon through microbial recyclers of organic matter in large-scale coccolithophore blooms.

microbiology↗