Influence Of Microbial Interactions Research Articles

Association Between Gut Akkermansia and Metabolic Syndrome is Dose-Dependent and Affected by Microbial Interactions: A Cross-Sectional Study.

ObjectiveAkkermansia muciniphila is among the most abundant bacterial species in the human intestine; however, its relationship to metabolic syndrome (MetS)—which is linked to gut dysbiosis—is not known. In this study, we investigated the association between Akkermansia abundance and risk of MetS and its components, as well as dose–response effects and the influence of microbial interactions on the association.MethodsThis cross-sectional study included 6896 Chinese participants aged 18 to 97 years from the Guangdong Gut Microbiome Project. MetS was defined according to Joint Committee for Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults criteria. The abundance of Akkermansia was assessed by 16S rRNA sequencing. Logistic regression analysis with adjustment for common confounders was performed to evaluate the association between Akkermansia and MetS and its components. Models with restricted cubic splines and interaction terms were used to examine the dose–response association and microbial interactions, respectively.ResultsThe prevalence of MetS was 20.4%, and the median abundance of Akkermansia was 0.08% (interquartile range: 0.04–0.93%). Increased Akkermansia abundance was associated with decreased risk of MetS (Pnonlinear<0.05), but this effect was not observed until the Akkermansia level was 0.2% of the total gut microbiota abundance (odds ratio=0.96, 95% confidence interval: 0.94–0.98). Of the 5 MetS components, obesity and hypertriglyceridemia showed the strongest association with Akkermansia, followed by reduced high-density lipoprotein cholesterol, hypertension, and hyperglycemia. Microbial interaction analyses showed that Ruminococcaceae and Lachnospiraceae were the predominant bacterial families and were not only correlated with Akkermansia abundance but also influenced the Akkermansia–MetS association.ConclusionThere is a dose–response association between reduced risk of MetS and increased abundance of Akkermansia. The association between Akkermansia and 5 MetS components is variable and affected by microbial interactions.

Influence of microbial interactions and EPS/polysaccharide composition on nutrient removal activity in biofilms formed by strains found in wastewater treatment systems

The study of biofilm function, structure and microbial interactions might help to improve our understanding of biofilm wastewater treatment processes. However, few reports specifically address the influence of interactions within multispecies biofilms on microbial activity and biofilm composition. Thus, the relationship between biofilm formation, denitrification activity, phosphorus removal and the composition of extracellular polymeric substances (EPS), exopolysaccharides and the bacterial community was investigated using biofilms of denitrifying and phosphorus removing strains Comamonas denitrificans 110, Brachymonas denitrificans B79, Aeromonas hydrophila L6 and Acinetobacter calcoaceticus ATCC23055. Denitrification activity within the biofilms generally increased with the amount of biofilm while phosphorus removal depended on bacterial growth rate. Synergistic effects of co-growth on denitrification ( B. denitrificans B79 and A. hydrophila L6) and phosphorus removal ( C. denitrificans 110 with either A. calcoaceticus or A. hydrophila L6) were observed. B. denitrificans B79 was highly affected by interspecies interactions with respect to biofilm formation, denitrification activity and EPS composition, while C. denitrificans 110 remained largely unaffected. In some of the dual and quadruple strain biofilms new exopolysaccharide monomers were detected which were not present in the pure strain samples.

Influence of microbial interactions on the susceptibility of Karenia spp. to algicidal bacteria

A bacterial strain (D38BY) belonging to the family Flavobacteriaceae and antagonistic towards an algicidal bacterium (strain S03; Flavobacteriaceae) was isolated from a culture of the red tide dinoflagellate Karenia brevis that had previously been characterized as resistant to attack by strain S03. This antagonistic bacterium increased the survival time of otherwise susceptible, bacteria- free K. brevis cultures in a concentration-dependent manner during exposure to the algicidal bac- terium. Experimental evidence indicated that direct contact was required in order for strain D38BY to inhibit the killing activity of algicidal strain S03. While further work is needed to determine its pre- cise mode of action, the antagonistic properties of strain D38BY provide further evidence that the resistance or susceptibility of certain algal taxa to algicidal attack can be more a function of inter- actions within the ambient microbial community than an intrinsic property of the alga.