ABSTRACT
Bifidobacterium bifidum is part of the core microbiota of healthy infant guts where it may form biofilms on epithelial cells, mucosa, and food particles in the gut lumen. Little is known about transcriptional changes in B. bifidum engaged in synergistic multispecies biofilms with ecologically relevant species of the human gut. Recently, we reported prevalence of synergism in mixed-species biofilms formed by the human gut microbiota. This study represents a comparative gene expression analysis of B. bifidum when grown in a single-species biofilm and in two multispecies biofilm consortia with Bifidobacterium longum subsp. infantis, Bacteroides ovatus, and Parabacteroides distasonis in order to identify genes involved in this adaptive process in mixed biofilms and the influence on its metabolic and functional traits. Changes up to 58% and 43% in its genome were found when it grew in three- and four-species biofilm consortia, respectively. Upregulation of genes of B. bifidum involved in carbohydrate metabolism (particularly the galE gene), quorum sensing (luxS and pfs), and amino acid metabolism (especially branched chain amino acids) in both multispecies biofilms, compared to single-species biofilms, suggest that they may be contributing factors for the observed synergistic biofilm production when B. bifidum coexists with other species in a biofilm.
Subject(s)
Bifidobacterium bifidum , Gastrointestinal Microbiome , Microbiota , Infant , Humans , Bifidobacterium bifidum/metabolism , Bifidobacterium/genetics , Bifidobacterium/metabolism , BiofilmsABSTRACT
Bacterial species in the human gut predominantly exist in the form of mixed-species biofilms on mucosal surfaces. In this study, the biofilm-forming ability of many human gut bacterial strains (133 strains recovered from human faeces) on mucin-coated and non-coated polystyrene surfaces was determined. A significant variation (P < 0.05) in the biofilm-forming ability of many bacterial species on both surfaces was noticed. Based on some preliminary trials, four bacterial species were selected (Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis, Parabacteroides distasonis and Bacteroides ovatus), which could not form any abundant biofilm individually under the in vitro conditions investigated, but produced abundant biofilms when co-cultured in different combinations of two, three and four species, giving an evidence of synergistic interactions in multispecies biofilm formation. There was a 4.74-fold increase in the biofilm mass when all strains developed a biofilm together. Strain-specific qPCR analysis showed that B. bifidum was the most dominant species (56%) in the four-species biofilm after 24 h, followed by B. longum subsp. infantis (36.2%). Study involving cell free supernatant of the cooperating strains showed that cell viability as well as physical presence of cooperating cells were prerequisites for the observed synergy in biofilms. The molecular mechanism behind these interactions and subsequent effects on the functionality of the strains involved were not determined in our study but merit further work.
Subject(s)
Biofilms , Gastrointestinal Microbiome , Mucins , Bacteroides , Bacteroidetes , Bifidobacterium bifidum , Bifidobacterium longum subspecies infantis , HumansABSTRACT
The O_2 collision cell technology was accepted to move the analyte to new oxide line position in stead of attenuating the double charge ions directly. A minus kinetic energy discrimination configuration was used to promote the oxide ions passing. An isobaric interference on new oxide line was corrected by a mathematic equation. It was found the enhancing effect of organic reagent benefit to As and Se oxide ion signal also. The 1% methanol sample solution was applied to improve the analyte sensitivity. The detection limits were 4.5 ng/L for As and 6.2 ng/L for Se. The background equivalent concentration was 0.022 μg/L for As and 0.025 μg/L for Se. The analysis errors enter into the allowed range of the standard material, which greatly improve the analytical accuracy of the actual sample.
ABSTRACT
Objective To observe the effet of gross saponin of tribulus terrestris(GSTT) on hemodynamics and oxygen metabolism in anesthetic thoraco-opened dogs.Methods Thirty dogs were randomly divided into negative control,positive control,and experimental groups(GSTT of 6.26,12.52,and 25.00 mg?kg~(-1))(n=6).The administration of intravenous injection was used.The effects of GSTT on the indexes of the hemodynamics and oxygen metabolism in anesthetic thoraco-opened dogs were observed.Results Compared with controls GSTT increased myocardial blood flow(CBF)(P
ABSTRACT
Objective To study the protective effects of total glycosides of Pacony(TGP) on acute myocardial infarction in dogs.Methods Thirty domestic dogs were randomly divided into 5 groups(6 in each group): model control group,positive control group(ISM),and TGP groups with doses of 2.0,4.0,and 8.0 mg?kg~(-1),respectively.The descending branch of left coronary artery was ligated to construct the model of myocardial infarction in the anesthetic thoraco-opened dogs.The effect of TGP on epicardium electrocardiogram(EECG),myocardial infarction size(MIS) and serum myocardial enzymes were observed.Results Compared with controls,the ischemia degree(∑-ST,P
ABSTRACT
Objective To study the effects of ShaJi on the indexes of oxygen metabolism such as coronary blood flow in myocardium of anesthetized thoraco-opened dogs. Methods Dogs were randomly divided into control group,4 and 16 mg?kg-1 ShaJi groups,and positive control group(n=6).The anesthetized thoraco-opened dog models were set up.The administration of intravenous injection was used by femoral vein.The blood pressure,heart rate and coronary blood flow(CBF) were measured.Coronary resistance,myocardial oxygen uptake rate,myocardial oxygen consumption index and myocardial oxygen consumption were calculated.Results Compared with control group,the CBF was increased (P0.05).Conclusion ShaJi can significantly ameliorate oxygen metabolism in myocardium of anesthetized thoraco-opened dogs.
ABSTRACT
Seventeen physiological,biochemicaland morphological indexes consistently showed that Astragalus polysaccharide was able to enhance the myocardia contractility,attenuate the area of myocardial infarction, and reduce the degree of myocardial damage of myocardially infarcted dog heart in vivo.The mechanism might be related to the inhibition of Na+-Kr+ATPase activity & the anti-free-radical-damage action.
