Relationship between clinical features and intestinal microbiota in Chinese patients with ulcerative colitis

BACKGROUND Dysbacteriosis may be a crucial environmental factor for ulcerative colitis(UC).Further study is required on microbiota alterations in the gastrointestinal tract of patients with UC for better clinical management and treatment.AIM To analyze the relationship between different clinical features and the intestinal microbiota,including bacteria and fungi,in Chinese patients with UC.METHODS Eligible inpatients were enrolled from January 1,2018 to June 30,2019,and stool and mucosa samples were collected.UC was diagnosed by endoscopy,pathology,Mayo Score,and Montreal classification.Gene amplicon sequencing of 16S rRNA gene and fungal internal transcribed spacer gene was used to detect the intestinal microbiota composition.Alpha diversity,principal component analysis,similarity analysis,and Metastats analysis were employed to evaluate differences among groups.RESULTS A total of 89 patients with UC and 33 non-inflammatory bowel disease(IBD)controls were enrolled.For bacterial analysis,72 stool and 48 mucosa samples were obtained from patients with UC and 21 stool and 12 mucosa samples were obtained from the controls.For fungal analysis,stool samples were obtained from 43 patients with UC and 15 controls.A significant difference existed between the fecal and mucosal bacteria of patients with UC.Theα-diversity of intestinal bacteria and the relative abundance of some families,such as Lachnospiraceae and Ruminococcaceae,decreased with the increasing severity of bowel inflammation,while Escherichia-Shigella showed the opposite trend.More intermicrobial correlations in UC in remission than in active patients were observed.The bacteriafungi correlations became single and uneven in patients with UC.CONCLUSION The intestinal bacteria flora of patients with UC differs significantly in terms of various sample types and disease activities.The intermicrobial correlations change in patients with UC compared with non-IBD controls.

Effects of probiotics and prebiotics on intestinal microbiota in mice with acute colitis based on 16S rRNA gene sequencing

Background:Imbalance of intestinal microbiota was closely related to colitis.Under these circumstances,regulation of enteric flora may be beneficial to the repair of inflammation.We aimed to investigate the effects of probiotics (Bifidobacterium and Lactobacillus),prebiotics and their combination on inflammation,and microflora in mice of acute colitis.Methods:C57BL/6J mice were divided into six groups randomly (blank control group,model control group,probiotics group,synbiotics group,lactitol group and probiotics + lactitol group).Each group was given 2.5% dextran sulfate sodium drinking water for 5 days other than the blank control group.Except for the model control group,the other four groups were intervened with probiotics,synbiotics (probiotics and inulin),lactitol,and probiotics + lactitol.Mice were sacrificed after 1 week of gavage,and pathologic scores were calculated.The feces of different periods and intestinal mucosa samples were collected to analyze the differences of intestinal microbiota by 16S rRNA sequencing.Differences of two groups or multiple groups were statistically examined through unpaired Student t test and analysis of variance (ANOVA),respectively.ANOVA,Tukey,Anosim,and metastats analysis were used to compare differences of microbiota among different groups.Results:After gavage for 1 week,the pathologic scores of groups with the intervention were significantly lower than those in the model control group,and the difference was statistically significant (P < 0.05).The model control group was higher in the genus of Bacteroides (relative abundance:0.3679 vs.0.0099,P =0.0016) and lower in Lactobacillus (relative abundance:0.0020 vs.0.0122,P =0.0188),Roseburia (relative abundance:0.0004 vs.0.0109,P =0.0157),compared with the blank control group.However,the same phenomenon was not found in groups gavaged with probiotics and lactitol.Compared with model control group,mice with intervention were increased with Bifidobacterium (relative abundance:0.0172 vs.0.0039,P =0.0139),Lachnospiraceae_NK4A136_group (relative abundance:0.1139 vs.0.0320,P =0.0344),Lachnospiraceae_UCG-006 (relative abundance:0.0432 vs.0.0054,P =0.0454),and decreased with Alistipes (relative abundance:0.0036 vs.0.0105,P =0.0207) in varying degrees.The mucosal flora was more abundant than the fecal flora,and genus of Mucispirillum (relative abundance:0.0207 vs.0.0001,P =0.0034) was more common in the mucosa.Lactitol group showed higher level of Akkermansia than model control group (relative abundance:0.0138 vs.0.0055,P =0.0415),probiotics group (relative abundance:0.0138 vs.0.0022,P =0.0041),and synbiotics group (relative abundance:0.0138 vs.0.0011,P =0.0034),while probiotics + lactitol group had more abundant Akkermansia than synbiotics group (relative abundance:0.0215 vs.0.0013,P =0.0315).Conclusions:Probiotics and prebiotics reduce the degree of inflammation in acute colitis mice obviously.Mice with acute colitis show reduced beneficial genera and increased harmful genera.Supplementation of probiotics and prebiotics display the advantage of increasing the proportion of helpful bacteria and regulating the balance of intestinal microbiota.Lactitol might promote the proliferation of Akkermansia.

Morphological Evolution of Fe-Rich Phases in the AlSi_9Cu_3Mg_(0.19)(Fe)Alloy with the Addition of Minor Mn and Cr

The morphological evolution of Fe-rich phases in the Alalloy has been investigated with various contents of Fe,Mn,and Cr.The results show that coarse Chinese script Fe-rich phases appear in the alloy with 0.6 wt%Fe combined with trace Mn,while the blocky Fe-rich phases appear combined with trace Cr.Under the coexistence of trace Mn and Cr,a large number of fine Chinese script Fe-rich phases could be visible in the low iron-bearing AlSi_9Cu_3-alloy（0.60 wt%）.At high Fe level（1.30 wt%）,numerous Fe-rich phases with hexagonal morphologies are observed with the trace Cr,while fish-bone and pentagonal morphologies of Fe-rich phases could be simultaneously observed with the addition of both Mn and Cr.The results reveal that the trace Mn and Cr promote the morphological evolution of Fe-rich phases.The morphology evolution mechanism of Fe-rich phases has been discussed by using the atom radius and electronegativity differences of Fe,Mn,and Cr.

Optimization of the quenching method for metabolomics analysis of Lactobacillus bulgaricus

This study proposed a quenching protocol for metabolite analysis of Lactobacillus delbrueckii subsp.bulgaricus.Microbial cells were quenched with 60% methanol/water,80% methanol/glycerol,or 80% methanol/water.The effect of the quenching process was assessed by the optical density（OD）-based method,flow cytometry,and gas chromatography-mass spectrometry（GC-MS）.The principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） were employed for metabolite identification.The results indicated that quenching with 80% methanol/water solution led to less damage to the L.bulgaricus cells,characterized by the lower relative fraction of prodium iodide（PI）-labeled cells and the higher OD recovery ratio.Through GC-MS analysis,higher levels of intracellular metabolites（including focal glutamic acid,aspartic acid,alanine,and AMP） and a lower leakage rate were detected in the sample quenched with 80% methanol/water compared with the others.In conclusion,we suggested a higher concentration of cold methanol quenching for L.bulgaricus metabolomics due to its decreasing metabolite leakage.