Background:The interaction between nutrition and immunity plays a vital role in nutrient digestion,absorption,and metabolism during poultry production.Recent studies showed that the gut microbiota contributes to the d...Background:The interaction between nutrition and immunity plays a vital role in nutrient digestion,absorption,and metabolism during poultry production.Recent studies showed that the gut microbiota contributes to the development of intestinal mucosal immunity.However,the mechanisms by which gut microbes regulate this process remain unclear.Methods:We compared the intestinal mucosal immunity and gut microbiota of Arbor Acre broilers AA(lower mucosal immunity)and Chinese native Wuliang Mountain Black-bone chickens(WLMB)(higher mucosal immunity)using 16S rDNA sequencing,transcriptomic analysis,and immunoglobulin A(IgA)antibody repertoire sequencing.We then combined 16S rDNA sequencing with transcriptomics to identify the key microbes and found that they were positively correlated with IgA production.Next,we transplanted candidate microbes into 1-day-old broiler to explore their role in intestinal mucosal immunity.Finally,we verified the function of candidate microbial metabolites in regulating the immune function of macrophages and the intestinal-epithelial cells(IECs)using in vitro experiments.Results:WLMB performs stronger mucosal immunity than AA,including higher IgA levels,more diverse IgA antibody repertoire,and higher bacterial affinity.Bacteroides was identified as the key microbes related to the intestinal IgA response.Bacteroides transplantation could increase IgA concentration in the duodenal contents by enhancing the expression of IgA,polymeric immunoglobin receptor(PIgR),B cell-activating factor of the TNF family(BAFF),and activation-induced cytidine deaminase(AID)in the duodenum.Additionally,Bacteroides-derived isovaleric acid promoted M2 macrophage polarization of macrophage via mTOR/PPAR-γ/STAT3 signaling pathways and regulated the immunologic function of IECs to produce cytokines,including interleukin(IL)-10,IL-4,BAFF,and transforming growth factor-beta(TGF-β),thus promoting IgA production in B cells by facilitating AID expression.Conclusion:Our study revealed that Bacteroides modulate the intestinal IgA response and maintain gut health in broilers.Bacteroides may be a promising alternative as an immunomodulatory microbial agent for developing nextgeneration probiotics for broiler production.展开更多
Polysaccharide was a class of macromolecular substance with various bioactive functions.Gut symbiotic microorganisms could utilize the polysaccharides from various sources,thus have important impact on human health.Ba...Polysaccharide was a class of macromolecular substance with various bioactive functions.Gut symbiotic microorganisms could utilize the polysaccharides from various sources,thus have important impact on human health.Bacteroides represented one of the dominant colonizers in the human gut.The utilization of polysaccharide by Bacteroides was important for supporting the function and stability of gut microbiota.After the degradation of polysaccharides by Bacteroides,gut microbes could ferment the monosaccharides and oligosaccharides degraded from polysaccharides into some metabolites,such as short-chain fatty acids(SCFAs),amino acids,etc.Among the metabolites,the SCFAs could have beneficial effects on gut health.This review summarized the niches of Bacteroides among gut microbiota,and also described the gene clusters and membrane proteins involved in the utilization processes of polysaccharide by gut Bacteroides.SCFAs could act as energy substrates for intestinal epithelial cells,inhibit histone deacetylases and activate G protein-coupled receptors.In addition,the future perspectives in investigating new degradation pathways for polysaccharide,and using polysaccharides or their metabolites as therapeutic approaches for diseases mediated by the gut dysbiosis were also provided.展开更多
AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant pro...AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 mu g), and a model + high-dose toxin (ADHT; n = 20, 20 mu g) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. RESULTS Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 +/- 0.68 vs 23.23 +/- 0.91, P < 0.05) and the ADHT group (21.82 +/- 0.68 vs 23.57 +/- 1.06, P < 0.05). More tumors were found in the AD group than in the ADLT and ADHT groups (19.75 +/- 3.30 vs 6.50 +/- 1.73, P < 0.05; 19.75 +/- 3.30 vs 6.00 +/- 2.16, P < 0.05). Pathology showed that 12 mice had adenocarcinoma and 6 cases had adenoma in the AD group. Five mice had adenocarcinoma and 15 had adenoma in the ADLT group. Four mice had adenocarcinoma and 16 had adenoma in the ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group (P < 0.05, P < 0.05). The positive rate of Ki-67 in the ADLT group and the ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P < 0.05, P < 0.05). Caspase-3 expression in the ADLT group and the ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). CONCLUSION Oral administration with lower-dose biologically active recombinant BFT-2 inhibited colorectal tumorigenesis in mice.展开更多
BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF...BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF-secreted toxin(BFT).Dendritic cells(DCs)play an important role in directing the nature of adaptive immune responses to bacterial infection and heme oxygenase-1(HO-1)is involved in the regulation of DC function.AIM To investigate the role of BFT in HO-1 expression in DCs.METHODS Murine DCs were generated from specific pathogen-free C57BL/6 and Nrf2−/−knockout mice.DCs were exposed to BFT,after which HO-1 expression and the related signaling factor activation were measured by quantitative RT-PCR,EMSA,fluorescent microscopy,immunoblot,and ELISA.RESULTS HO-1 expression was upregulated in DCs stimulated with BFT.Although BFT activated transcription factors such as NF-κB,AP-1,and Nrf2,activation of NF-κB and AP-1 was not involved in the induction of HO-1 expression in BFT-exposed DCs.Instead,upregulation of HO-1 expression was dependent on Nrf2 activation in DCs.Moreover,HO-1 expression via Nrf2 in DCs was regulated by mitogenactivated protein kinases such as ERK and p38.Furthermore,BFT enhanced the production of reactive oxygen species(ROS)and inhibition of ROS production resulted in a significant decrease of phospho-ERK,phospho-p38,Nrf2,and HO-1 CONCLUSION These results suggest that signaling pathways involving ROS-mediated ERK and p38 mitogen-activated protein kinases-Nrf2 activation in DCs are required for HO-1 induction during exposure to ETBF-produced BFT.展开更多
The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with som...The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence(IS) elements, which are usually regarded as representatives of ‘selfish' genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A(penicillin and cephalosporin), cfx A(cephamycin), cfi A(carbapenem), nim(metronidazole) and erm F(clindamycin) resistance genes. This is achieved by outwardoriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.展开更多
Rationale:Endophthalmitis is an uncommon but serious ocular infection often resulting in probable visual loss.Bacteroides fragilis is a rare cause of endophthalmitis.Patient concerns:A 46-year-old male patient complai...Rationale:Endophthalmitis is an uncommon but serious ocular infection often resulting in probable visual loss.Bacteroides fragilis is a rare cause of endophthalmitis.Patient concerns:A 46-year-old male patient complained of eye pain and low vision after pars plana vitrectomy.Diagnosis:Bacteroides fragilis endophthalmitis after pars plana vitrectomy was diagnosed.Interventions:Pars plana vitrectomy and silicone oil implantation were performed.Outcomes:Early treatment and choice of tamponade in endophthalmitis after pars plana vitrectomy may possibly prevent evisceration and progression of endophthalmitis.Lessons:Bacteroides fragilis can be seen in cases of endophthalmitis after pars plana vitrectomy.展开更多
Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the oppo...Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the opportunistic ones, being the most isolated anaerobic bacteria in clinical samples. Cell-free supernatants of 65 B. fragilis strains were assayed and they were capable of inducing vacuolating phenotype on Vero cells lineage. The supernatant of the Bacteroides fragilis ATCC 23745 strain was elicited to have the strongest vacuolating effect on Vero cells monolayers and peritoneal macrophages. Some drastic cell alterations were observed, such as a general disorganization of cytoplasm and chromatin condensation, evidencing cell death. By transmission electron microscopy it was confirmed that the vacuoles observed were, in fact, swollen mitochondria. An immunocytochemical assay, TUNEL, was used to confirm this hypothesis and showed that Vero cells and peritoneal macrophages were dying by apoptotic process after exposition of B. fragilis cell-free supernatant. Physical analysis of the apoptotic factor has revealed properties similar to short-chain fatty acids. After gas chromatography and mass spectrometry analysis, phenylacetic acid (PA) was characterized as the major compound present in the most purified active fraction. We believe that the PA is responsible for the pro-apoptotic effect elicited by the supernatant of B. fragilis cultures.展开更多
Sugarcane leaves-derived polyphenols(SLP)have been demonstrated to have diverse health-promoting benefits,but the mechanism of action has not been fully elucidated.This study aimed to investigate the anti-metabolic di...Sugarcane leaves-derived polyphenols(SLP)have been demonstrated to have diverse health-promoting benefits,but the mechanism of action has not been fully elucidated.This study aimed to investigate the anti-metabolic disease effects of SLP and the underlying mechanisms in mice.In the current study,we prepared the SLP mainly consisting of three flavonoid glycosides,three phenol derivatives,and two lignans including one new compound,and further demonstrated that SLP reduced body weight gain and fat accumulation,improved glucose and lipid metabolism disorders,ameliorated hepatic steatosis,and regulated short-chain fatty acids(SCFAs)production and secondary bile acids metabolism in ob/ob mice.Notably,SLP largely altered the gut microbiota composition,especially enriching the commensal bacteria Akkermansia muciniphila and Bacteroides acidifaciens.Oral gavage with the above two strains ameliorated metabolic syndrome(MetS),regulated secondary bile acid metabolism,and increased the production of SCFAs in high-fat diet(HFD)-induced obese mice.These results demonstrated that SLP could be used as a prebiotic to attenuate MetS via regulating gut microbiota composition and further activating the secondary bile acids-mediated gut-adipose axis.展开更多
Fusobacterium vincentii brain abscesses are relatively rare.Here,we report our treatment of an anaerobic brain abscess caused by a mixed infection of Parvimonas micra,Streptococcus constellatus,Fusobacterium vincentii...Fusobacterium vincentii brain abscesses are relatively rare.Here,we report our treatment of an anaerobic brain abscess caused by a mixed infection of Parvimonas micra,Streptococcus constellatus,Fusobacterium vincentii,and Bacteroides heparinolyticus diagnosed by metagenomic next-generation sequencing(mNGS).This is the first re-ported case of Fusobacterium vincentii in a brain abscess.This case highlights the possibility that oral anaerobic microbes can cause a brain abscess and demonstrates that mNGS has the potential to be deployed to provide rapid infection diagnosis and rationalize antimicrobial therapy for brain abscesses.展开更多
Growing evidences show a direct link between diarrhea and disorders of gut microbiota in pigs.However,whether there are microbial markers associated with post-weaning diarrhea remains unknown.In the current study,we c...Growing evidences show a direct link between diarrhea and disorders of gut microbiota in pigs.However,whether there are microbial markers associated with post-weaning diarrhea remains unknown.In the current study,we compared the microbial community,functions and metabolites between healthy weaned piglets(group H,n=7)and piglets with post-weaning diarrhea(group D,n=7),in order to find out diarrhea associated microbial markers.Each of 7 fecal samples was collected from H and D piglets(weaned at 21 d and sampled at 26 d).The metagenomic and untargeted metabolomic analysis revealed that the microbial composition,function and metabolic profile in D pigs was considerably reshaped,including the reduced abundance and number of Bacteroides,which significantly correlated with the diarrhea status of host.The carbohydrate metabolism,biosynthesis and metabolism,lipid metabolism,amino acid metabolism,and the activity of glycan and carbohydrates digestion related enzymes showed extensively down-regulated in D pigs compared with H pigs.Diarrhea significantly changed the metabolic profiles of fecal microbiota,and most of the altered metabolites were negatively or positively correlated with the change in the abundance of Bacteroides.In conclusion,the lower abundance of Bacteroides and its associated metabolic dysfunction may be regarded as microbial markers of physiological post-weaning diarrhea in piglets.展开更多
Type 2 diabetes(T2D)is highly associated with obesity.However,the factors that drive the transition from excessive weight gain to glucose metabolism disruption are still uncertain and seem to revolve around systemic i...Type 2 diabetes(T2D)is highly associated with obesity.However,the factors that drive the transition from excessive weight gain to glucose metabolism disruption are still uncertain and seem to revolve around systemic immune disorder.Mucosal-associated invariant T(MAIT)cells,which are innate-like T cells that recognize bacterial metabolites,have been reported to be altered in obese people and to lead to metabolic dysfunction during obesity.By studying the immunophenotypes of blood MAIT cells from a cross-sectional cohort of obese participants with/without T2D,we found an elevation in CD27^(-)negative(CD27−)MAIT cells producing a high level of IL-17 under T2D obese conditions,which could be positively correlated with impaired glucose metabolism in obese people.We further explored microbial translocation caused by gut barrier dysfunction in obese people as a triggering factor of MAIT cell abnormalities.Specifically,accumulation of the bacterial strain Bacteroides ovatus in the peripheral blood drove IL-17^(-)producing CD27−MAIT cell expansion and could be associated with T2D risk in obese individuals.Overall,these results suggest that an aberrant gut microbiota–immune axis in obese people may drive or exacerbate T2D.Importantly,CD27−MAIT cell subsets and Bacteroides ovatus could represent targets for novel interventional strategies.Our findings extend current knowledge regarding the clinical relevance of body mass index(BMI)-associated variation in circulating MAIT cells to reveal the role of these cells in obesity-related T2D progression and the underlying cellular mechanisms.展开更多
Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognitio...Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognition,selectin-mediated leukocyteendothelial adhesion and the formation of Lewis blood group antigens(Ma et al.,2006).GDP-fucose is an important fucose donor in the process of fucosylated oligosaccharides formation.Two pathways of GDP-fucose synthesis are present in the cytosol of mammalian cells,including the de novo pathway and the salvage pathway(Becker et al.,2003).In the salvage pathway,cells use fucose from the extracellular or lysosomal sources to synthesize GDP-fucose.展开更多
Objective To investigate the distribution of various bacteria in adenoma tissue of colorectal adenoma(T/CRA),normal colonic mucosa tissue adjacent to the adenoma(N/CRA),and healthy colonic mucosa tissue(N/H)by compari...Objective To investigate the distribution of various bacteria in adenoma tissue of colorectal adenoma(T/CRA),normal colonic mucosa tissue adjacent to the adenoma(N/CRA),and healthy colonic mucosa tissue(N/H)by comparing the number of total bacteria,Bacteroides fragilis(BF),enterotoxigenic Bacteroides展开更多
基金supported by the National Natural Science Foundation of China (31925037)to XHY。
文摘Background:The interaction between nutrition and immunity plays a vital role in nutrient digestion,absorption,and metabolism during poultry production.Recent studies showed that the gut microbiota contributes to the development of intestinal mucosal immunity.However,the mechanisms by which gut microbes regulate this process remain unclear.Methods:We compared the intestinal mucosal immunity and gut microbiota of Arbor Acre broilers AA(lower mucosal immunity)and Chinese native Wuliang Mountain Black-bone chickens(WLMB)(higher mucosal immunity)using 16S rDNA sequencing,transcriptomic analysis,and immunoglobulin A(IgA)antibody repertoire sequencing.We then combined 16S rDNA sequencing with transcriptomics to identify the key microbes and found that they were positively correlated with IgA production.Next,we transplanted candidate microbes into 1-day-old broiler to explore their role in intestinal mucosal immunity.Finally,we verified the function of candidate microbial metabolites in regulating the immune function of macrophages and the intestinal-epithelial cells(IECs)using in vitro experiments.Results:WLMB performs stronger mucosal immunity than AA,including higher IgA levels,more diverse IgA antibody repertoire,and higher bacterial affinity.Bacteroides was identified as the key microbes related to the intestinal IgA response.Bacteroides transplantation could increase IgA concentration in the duodenal contents by enhancing the expression of IgA,polymeric immunoglobin receptor(PIgR),B cell-activating factor of the TNF family(BAFF),and activation-induced cytidine deaminase(AID)in the duodenum.Additionally,Bacteroides-derived isovaleric acid promoted M2 macrophage polarization of macrophage via mTOR/PPAR-γ/STAT3 signaling pathways and regulated the immunologic function of IECs to produce cytokines,including interleukin(IL)-10,IL-4,BAFF,and transforming growth factor-beta(TGF-β),thus promoting IgA production in B cells by facilitating AID expression.Conclusion:Our study revealed that Bacteroides modulate the intestinal IgA response and maintain gut health in broilers.Bacteroides may be a promising alternative as an immunomodulatory microbial agent for developing nextgeneration probiotics for broiler production.
基金the National Science Fund for Distinguished Young Scholars of China(31825020)。
文摘Polysaccharide was a class of macromolecular substance with various bioactive functions.Gut symbiotic microorganisms could utilize the polysaccharides from various sources,thus have important impact on human health.Bacteroides represented one of the dominant colonizers in the human gut.The utilization of polysaccharide by Bacteroides was important for supporting the function and stability of gut microbiota.After the degradation of polysaccharides by Bacteroides,gut microbes could ferment the monosaccharides and oligosaccharides degraded from polysaccharides into some metabolites,such as short-chain fatty acids(SCFAs),amino acids,etc.Among the metabolites,the SCFAs could have beneficial effects on gut health.This review summarized the niches of Bacteroides among gut microbiota,and also described the gene clusters and membrane proteins involved in the utilization processes of polysaccharide by gut Bacteroides.SCFAs could act as energy substrates for intestinal epithelial cells,inhibit histone deacetylases and activate G protein-coupled receptors.In addition,the future perspectives in investigating new degradation pathways for polysaccharide,and using polysaccharides or their metabolites as therapeutic approaches for diseases mediated by the gut dysbiosis were also provided.
基金Supported by the Scientific Research Project of Shanghai Health and Family Planning,and the Commission and the 5th People’s Hospital of Shanghai,Fudan University under Grant No.201440505
文摘AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 mu g), and a model + high-dose toxin (ADHT; n = 20, 20 mu g) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. RESULTS Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 +/- 0.68 vs 23.23 +/- 0.91, P < 0.05) and the ADHT group (21.82 +/- 0.68 vs 23.57 +/- 1.06, P < 0.05). More tumors were found in the AD group than in the ADLT and ADHT groups (19.75 +/- 3.30 vs 6.50 +/- 1.73, P < 0.05; 19.75 +/- 3.30 vs 6.00 +/- 2.16, P < 0.05). Pathology showed that 12 mice had adenocarcinoma and 6 cases had adenoma in the AD group. Five mice had adenocarcinoma and 15 had adenoma in the ADLT group. Four mice had adenocarcinoma and 16 had adenoma in the ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group (P < 0.05, P < 0.05). The positive rate of Ki-67 in the ADLT group and the ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P < 0.05, P < 0.05). Caspase-3 expression in the ADLT group and the ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). CONCLUSION Oral administration with lower-dose biologically active recombinant BFT-2 inhibited colorectal tumorigenesis in mice.
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education,Science and Technology,South Korea,No.NRF-2018R1D1A1B07043350
文摘BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF-secreted toxin(BFT).Dendritic cells(DCs)play an important role in directing the nature of adaptive immune responses to bacterial infection and heme oxygenase-1(HO-1)is involved in the regulation of DC function.AIM To investigate the role of BFT in HO-1 expression in DCs.METHODS Murine DCs were generated from specific pathogen-free C57BL/6 and Nrf2−/−knockout mice.DCs were exposed to BFT,after which HO-1 expression and the related signaling factor activation were measured by quantitative RT-PCR,EMSA,fluorescent microscopy,immunoblot,and ELISA.RESULTS HO-1 expression was upregulated in DCs stimulated with BFT.Although BFT activated transcription factors such as NF-κB,AP-1,and Nrf2,activation of NF-κB and AP-1 was not involved in the induction of HO-1 expression in BFT-exposed DCs.Instead,upregulation of HO-1 expression was dependent on Nrf2 activation in DCs.Moreover,HO-1 expression via Nrf2 in DCs was regulated by mitogenactivated protein kinases such as ERK and p38.Furthermore,BFT enhanced the production of reactive oxygen species(ROS)and inhibition of ROS production resulted in a significant decrease of phospho-ERK,phospho-p38,Nrf2,and HO-1 CONCLUSION These results suggest that signaling pathways involving ROS-mediated ERK and p38 mitogen-activated protein kinases-Nrf2 activation in DCs are required for HO-1 induction during exposure to ETBF-produced BFT.
基金Supported by The Center of Excellence at the University of Szeged(TáMOP-421B)to József Sóki.
文摘The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence(IS) elements, which are usually regarded as representatives of ‘selfish' genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A(penicillin and cephalosporin), cfx A(cephamycin), cfi A(carbapenem), nim(metronidazole) and erm F(clindamycin) resistance genes. This is achieved by outwardoriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.
文摘Rationale:Endophthalmitis is an uncommon but serious ocular infection often resulting in probable visual loss.Bacteroides fragilis is a rare cause of endophthalmitis.Patient concerns:A 46-year-old male patient complained of eye pain and low vision after pars plana vitrectomy.Diagnosis:Bacteroides fragilis endophthalmitis after pars plana vitrectomy was diagnosed.Interventions:Pars plana vitrectomy and silicone oil implantation were performed.Outcomes:Early treatment and choice of tamponade in endophthalmitis after pars plana vitrectomy may possibly prevent evisceration and progression of endophthalmitis.Lessons:Bacteroides fragilis can be seen in cases of endophthalmitis after pars plana vitrectomy.
基金supported by grants from the following institutions:CAPES,CNPq,Faperj,Pronex and MCT-CNPq.
文摘Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the opportunistic ones, being the most isolated anaerobic bacteria in clinical samples. Cell-free supernatants of 65 B. fragilis strains were assayed and they were capable of inducing vacuolating phenotype on Vero cells lineage. The supernatant of the Bacteroides fragilis ATCC 23745 strain was elicited to have the strongest vacuolating effect on Vero cells monolayers and peritoneal macrophages. Some drastic cell alterations were observed, such as a general disorganization of cytoplasm and chromatin condensation, evidencing cell death. By transmission electron microscopy it was confirmed that the vacuoles observed were, in fact, swollen mitochondria. An immunocytochemical assay, TUNEL, was used to confirm this hypothesis and showed that Vero cells and peritoneal macrophages were dying by apoptotic process after exposition of B. fragilis cell-free supernatant. Physical analysis of the apoptotic factor has revealed properties similar to short-chain fatty acids. After gas chromatography and mass spectrometry analysis, phenylacetic acid (PA) was characterized as the major compound present in the most purified active fraction. We believe that the PA is responsible for the pro-apoptotic effect elicited by the supernatant of B. fragilis cultures.
基金supported by the National key research and development program of China(2019YFA0905600)the Science and Technology Service Network Program of the Chinese Academy of Sciences(KFJ-STS-QYZD-201-5-3)the Strategic Priority Research Program(Class B)of Chinese Academy of Sciences(XDB 38020300)。
文摘Sugarcane leaves-derived polyphenols(SLP)have been demonstrated to have diverse health-promoting benefits,but the mechanism of action has not been fully elucidated.This study aimed to investigate the anti-metabolic disease effects of SLP and the underlying mechanisms in mice.In the current study,we prepared the SLP mainly consisting of three flavonoid glycosides,three phenol derivatives,and two lignans including one new compound,and further demonstrated that SLP reduced body weight gain and fat accumulation,improved glucose and lipid metabolism disorders,ameliorated hepatic steatosis,and regulated short-chain fatty acids(SCFAs)production and secondary bile acids metabolism in ob/ob mice.Notably,SLP largely altered the gut microbiota composition,especially enriching the commensal bacteria Akkermansia muciniphila and Bacteroides acidifaciens.Oral gavage with the above two strains ameliorated metabolic syndrome(MetS),regulated secondary bile acid metabolism,and increased the production of SCFAs in high-fat diet(HFD)-induced obese mice.These results demonstrated that SLP could be used as a prebiotic to attenuate MetS via regulating gut microbiota composition and further activating the secondary bile acids-mediated gut-adipose axis.
基金supported by the Taishan Scholars Project(tsqn202306003)the Shandong Excellent Young Scientists Fund Program(2022HWYQ-056)the Program of Science and Technology of Suzhou(2022SS15).
文摘Fusobacterium vincentii brain abscesses are relatively rare.Here,we report our treatment of an anaerobic brain abscess caused by a mixed infection of Parvimonas micra,Streptococcus constellatus,Fusobacterium vincentii,and Bacteroides heparinolyticus diagnosed by metagenomic next-generation sequencing(mNGS).This is the first re-ported case of Fusobacterium vincentii in a brain abscess.This case highlights the possibility that oral anaerobic microbes can cause a brain abscess and demonstrates that mNGS has the potential to be deployed to provide rapid infection diagnosis and rationalize antimicrobial therapy for brain abscesses.
基金supported by the National Natural Science Foundation of China(31730091,31872369 and 31672436)。
文摘Growing evidences show a direct link between diarrhea and disorders of gut microbiota in pigs.However,whether there are microbial markers associated with post-weaning diarrhea remains unknown.In the current study,we compared the microbial community,functions and metabolites between healthy weaned piglets(group H,n=7)and piglets with post-weaning diarrhea(group D,n=7),in order to find out diarrhea associated microbial markers.Each of 7 fecal samples was collected from H and D piglets(weaned at 21 d and sampled at 26 d).The metagenomic and untargeted metabolomic analysis revealed that the microbial composition,function and metabolic profile in D pigs was considerably reshaped,including the reduced abundance and number of Bacteroides,which significantly correlated with the diarrhea status of host.The carbohydrate metabolism,biosynthesis and metabolism,lipid metabolism,amino acid metabolism,and the activity of glycan and carbohydrates digestion related enzymes showed extensively down-regulated in D pigs compared with H pigs.Diarrhea significantly changed the metabolic profiles of fecal microbiota,and most of the altered metabolites were negatively or positively correlated with the change in the abundance of Bacteroides.In conclusion,the lower abundance of Bacteroides and its associated metabolic dysfunction may be regarded as microbial markers of physiological post-weaning diarrhea in piglets.
基金This study was funded by the National Key R&D Program of China(2017YFA0105803)the National Natural Science Foundation of China(32000621 and 81770826)+3 种基金the Key Area R&D Program of Guangdong Province(2019B020227003)the Science and Technology Plan Project of Guangzhou City(202102010338 and 202007040003)the 5010 Clinical Research Projects of Sun Yat-sen University(2015015)the Dengfeng Plan High-level Hospital Construction Opening Project of Foshan Fourth People’s Hospital(FSSYKF-2020009).
文摘Type 2 diabetes(T2D)is highly associated with obesity.However,the factors that drive the transition from excessive weight gain to glucose metabolism disruption are still uncertain and seem to revolve around systemic immune disorder.Mucosal-associated invariant T(MAIT)cells,which are innate-like T cells that recognize bacterial metabolites,have been reported to be altered in obese people and to lead to metabolic dysfunction during obesity.By studying the immunophenotypes of blood MAIT cells from a cross-sectional cohort of obese participants with/without T2D,we found an elevation in CD27^(-)negative(CD27−)MAIT cells producing a high level of IL-17 under T2D obese conditions,which could be positively correlated with impaired glucose metabolism in obese people.We further explored microbial translocation caused by gut barrier dysfunction in obese people as a triggering factor of MAIT cell abnormalities.Specifically,accumulation of the bacterial strain Bacteroides ovatus in the peripheral blood drove IL-17^(-)producing CD27−MAIT cell expansion and could be associated with T2D risk in obese individuals.Overall,these results suggest that an aberrant gut microbiota–immune axis in obese people may drive or exacerbate T2D.Importantly,CD27−MAIT cell subsets and Bacteroides ovatus could represent targets for novel interventional strategies.Our findings extend current knowledge regarding the clinical relevance of body mass index(BMI)-associated variation in circulating MAIT cells to reveal the role of these cells in obesity-related T2D progression and the underlying cellular mechanisms.
文摘Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognition,selectin-mediated leukocyteendothelial adhesion and the formation of Lewis blood group antigens(Ma et al.,2006).GDP-fucose is an important fucose donor in the process of fucosylated oligosaccharides formation.Two pathways of GDP-fucose synthesis are present in the cytosol of mammalian cells,including the de novo pathway and the salvage pathway(Becker et al.,2003).In the salvage pathway,cells use fucose from the extracellular or lysosomal sources to synthesize GDP-fucose.
文摘Objective To investigate the distribution of various bacteria in adenoma tissue of colorectal adenoma(T/CRA),normal colonic mucosa tissue adjacent to the adenoma(N/CRA),and healthy colonic mucosa tissue(N/H)by comparing the number of total bacteria,Bacteroides fragilis(BF),enterotoxigenic Bacteroides