The bacterial community of the bowel of humans and other animals derives carbon and energy sources from the diet and secretions of the host. The metabolic products generated by the community, and the antigens and other molecules associated with the bacterial cells, interact with the bowel mucosa. Some bacterial products are absorbed from the bowel and affect the systemic organs of the body. The interactions that occur within the bacterial community and between the community and food components and host tissues comprise a highly interactive web. It is concluded that this interactive matrix characteristic of the bowel ecosystem may be studied by detailed autecological and synecological experiments. The results of these studies could be used to construct a general blueprint of the healthy bowel and might reveal biomarkers predictive of health or disease.
{"title":"Research for the 21st Century: Can We Draw a Blueprint of the Bowel Ecosystem?","authors":"G. Tannock","doi":"10.12938/BIFIDUS.28.75","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.75","url":null,"abstract":"The bacterial community of the bowel of humans and other animals derives carbon and energy sources from the diet and secretions of the host. The metabolic products generated by the community, and the antigens and other molecules associated with the bacterial cells, interact with the bowel mucosa. Some bacterial products are absorbed from the bowel and affect the systemic organs of the body. The interactions that occur within the bacterial community and between the community and food components and host tissues comprise a highly interactive web. It is concluded that this interactive matrix characteristic of the bowel ecosystem may be studied by detailed autecological and synecological experiments. The results of these studies could be used to construct a general blueprint of the healthy bowel and might reveal biomarkers predictive of health or disease.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"75-80"},"PeriodicalIF":0.0,"publicationDate":"2009-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66340016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ai Tamura, Eri Nishio, K. Fujimori, S. Igimi, F. Amano
An assay method was established for estimation of dry-resistance of Salmonella. Environmental isolates of Salmonella enterica spp., including S. Enteritidis were grown to the logarithmic phase, washed and re-suspended in saline or Luria-Bertani (LB) medium, followed by drying overnight in an automatic dry-keeper at room temperature. The dried bacteria were recovered by mixing with ice-cold PBS, suspended, and examined for viability by colony-forming activity. A pathogenic clone of S. Enteritidis, SECI#15-1, was not viable in saline alone but maintained its viability in LB medium, suggesting it requires nutrients for the acquisition of dry-resistance. Addition of lactoferrin or apolactoferrin to the bacterial suspension in 20% LB medium prior to the dry-protocol decreased the viability of SECI#15-1 in a dose-dependent manner. However, lactoferrin showed no effect on the growth of SECI#15-1 in liquid culture with LB or M9 medium, suggesting that it exerts bactericidal effects under dry but not under wet conditions. Besides, Salmonella spp. other than S. Emteritidis, such as S. Typhimurium, S. Oranienburg, S. Weltevreden, S. Johannesburg, and S. lnfantis, also showed dry-resistance, which was significantly inhibited by lactoferrin and almost entirely by apolactoferrin. These results suggest that lactoferrin inhibits the acquisition of dry-resistance by Salmonella spp., suggesting that there is a possible use for lactoferrin in the control of Salmonella food-poisoning as an additive in dry food.
{"title":"Lactoferrin inhibits the acquisition of dry-resistance of Salmonella spp.","authors":"Ai Tamura, Eri Nishio, K. Fujimori, S. Igimi, F. Amano","doi":"10.12938/BIFIDUS.28.81","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.81","url":null,"abstract":"An assay method was established for estimation of dry-resistance of Salmonella. Environmental isolates of Salmonella enterica spp., including S. Enteritidis were grown to the logarithmic phase, washed and re-suspended in saline or Luria-Bertani (LB) medium, followed by drying overnight in an automatic dry-keeper at room temperature. The dried bacteria were recovered by mixing with ice-cold PBS, suspended, and examined for viability by colony-forming activity. A pathogenic clone of S. Enteritidis, SECI#15-1, was not viable in saline alone but maintained its viability in LB medium, suggesting it requires nutrients for the acquisition of dry-resistance. Addition of lactoferrin or apolactoferrin to the bacterial suspension in 20% LB medium prior to the dry-protocol decreased the viability of SECI#15-1 in a dose-dependent manner. However, lactoferrin showed no effect on the growth of SECI#15-1 in liquid culture with LB or M9 medium, suggesting that it exerts bactericidal effects under dry but not under wet conditions. Besides, Salmonella spp. other than S. Emteritidis, such as S. Typhimurium, S. Oranienburg, S. Weltevreden, S. Johannesburg, and S. lnfantis, also showed dry-resistance, which was significantly inhibited by lactoferrin and almost entirely by apolactoferrin. These results suggest that lactoferrin inhibits the acquisition of dry-resistance by Salmonella spp., suggesting that there is a possible use for lactoferrin in the control of Salmonella food-poisoning as an additive in dry food.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"81-88"},"PeriodicalIF":0.0,"publicationDate":"2009-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While the intestinal immune system coexists[DPM1] with commensal bacterial flora through immunological tolerance, invading microorganisms are recognized and properly eliminated. However, it remains unknown what kinds of cells in the intestine initiate immune responses and how they activate host immunity. Recently, we identified a subset of CD11c hi CD11b hi lamina propria (LP) dendritic cells (DCs) as TLR5-expressing cells, which have the ability to activate adaptive immune responses. The LPDCs induced antigen-specific Th17 cells as well as Th1 cells in a TLR5-dependent manner. In addition, they acted on naive B cells to induce their development to immunoglobulin A (IgA) + plasma cells in response to flagellin, and such IgA + plasma cell generation took place in a gut-associated lymphoid tissue (GALT)-independent fashion. Our findings demonstrate unique properties of LPDCs and the importance of TLR5 for adaptive immunity in the intestine. We also generated and examined mutant mice of ATG16L1. ATG16L1 is a component of autophagy machinery and has been reported to be a candidate gene responsible for susceptibility to Crohn's disease. We discuss a novel role for autophagy in the regulation of the inflammatory immune responses in the intestine.
肠道免疫系统通过免疫耐受与共生菌群共存[DPM1]，入侵微生物被识别并适当清除。然而，目前尚不清楚肠道中哪种细胞启动免疫反应以及它们如何激活宿主免疫。最近，我们发现CD11c hi CD11b hi固有层(LP)树突状细胞(dc)的一个亚群作为tlr5表达细胞，具有激活适应性免疫反应的能力。LPDCs以tlr5依赖的方式诱导抗原特异性Th17细胞和Th1细胞。此外，它们作用于幼稚B细胞，诱导其发育为免疫球蛋白A (IgA) +浆细胞，以响应鞭毛蛋白，这种IgA +浆细胞的生成以肠道相关淋巴组织(GALT)不依赖的方式发生。我们的研究结果证明了LPDCs的独特特性以及TLR5对肠道适应性免疫的重要性。我们还生成并检测了ATG16L1突变小鼠。ATG16L1是自噬机制的一个组成部分，据报道是导致克罗恩病易感性的候选基因。我们讨论了自噬在肠道炎症免疫反应调节中的新作用。
{"title":"Intestine and Innate Immunity","authors":"S. Uematsu, S. Akira","doi":"10.12938/BIFIDUS.28.69","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.69","url":null,"abstract":"While the intestinal immune system coexists[DPM1] with commensal bacterial flora through immunological tolerance, invading microorganisms are recognized and properly eliminated. However, it remains unknown what kinds of cells in the intestine initiate immune responses and how they activate host immunity. Recently, we identified a subset of CD11c hi CD11b hi lamina propria (LP) dendritic cells (DCs) as TLR5-expressing cells, which have the ability to activate adaptive immune responses. The LPDCs induced antigen-specific Th17 cells as well as Th1 cells in a TLR5-dependent manner. In addition, they acted on naive B cells to induce their development to immunoglobulin A (IgA) + plasma cells in response to flagellin, and such IgA + plasma cell generation took place in a gut-associated lymphoid tissue (GALT)-independent fashion. Our findings demonstrate unique properties of LPDCs and the importance of TLR5 for adaptive immunity in the intestine. We also generated and examined mutant mice of ATG16L1. ATG16L1 is a component of autophagy machinery and has been reported to be a candidate gene responsible for susceptibility to Crohn's disease. We discuss a novel role for autophagy in the regulation of the inflammatory immune responses in the intestine.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"69-74"},"PeriodicalIF":0.0,"publicationDate":"2009-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qi Wang, Jingzhi Pan, M. Kawase, M. Hiramatsu, F. He
Lactobacillus gasseri TMC0356 (TMC0356), a probiotic strain originally isolated from the human intestine, was tested for its anti-tumor activities in vivo in murine tumor models. Oral administration of TMC0356 characteristically inhibited the growth of sarcoma S-180 (S-180) and hepatoma H22 (H22) cells, which had been implanted in mice. Serum gamma interferon was significantly enhanced during TMC0356 administration of 1,000 mg/kg in S-180-bearing mice (p<0.01). Serum levels of tumor necrosis factor-α and interleukin-18 were also altered, though these changes were not statistically significant. These results indicate that the anti-tumor effects of TMC0356 might, at least in part, arise from the impact of this bacterium on cell-mediated immunity in host animals.
{"title":"Orally Administrated Lactobacillus gasseri TMC0356 Inhibits Growth of Tumors Transplanted into Mice","authors":"Qi Wang, Jingzhi Pan, M. Kawase, M. Hiramatsu, F. He","doi":"10.12938/BIFIDUS.28.39","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.39","url":null,"abstract":"Lactobacillus gasseri TMC0356 (TMC0356), a probiotic strain originally isolated from the human intestine, was tested for its anti-tumor activities in vivo in murine tumor models. Oral administration of TMC0356 characteristically inhibited the growth of sarcoma S-180 (S-180) and hepatoma H22 (H22) cells, which had been implanted in mice. Serum gamma interferon was significantly enhanced during TMC0356 administration of 1,000 mg/kg in S-180-bearing mice (p<0.01). Serum levels of tumor necrosis factor-α and interleukin-18 were also altered, though these changes were not statistically significant. These results indicate that the anti-tumor effects of TMC0356 might, at least in part, arise from the impact of this bacterium on cell-mediated immunity in host animals.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"5 1","pages":"39-43"},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We examined the immunomodulation capability of Bifidobacterium longum strains via a Transwell co-culture system using human colonic epithelial cells, Caco-2, in the upper chamber, and human macrophage-like cells, THP1, in the lower chamber of the culture. Heat-treated cells of three B. longum strains, JCM1217 T , KT237 or H7-115, were added to the upper chamber to allow direct contact with Caco-2 cells and the culture was incubated for 24 hr. After incubation, THP-1 cells in the lower chamber were placed in a separate well containing fresh medium with LPS and incubated for 6 hr. After incubation, we found that TNF-α secretion from THP-1 cells, that had been co-cultured with Caco-2 directly contacting heat-treated cells of B. longum strains, especially H7-115, was suppressed. This was, however, not the case in an the almost identical experiment using B. longum cells killed under ultra-violet light (not heat-treated). We then blocked Caco-2 TLR2 with anti-TLR 2 antibodies in another co-culture experiment and found that blocking TLR2 canceled the indirect anti-inflammatory effect of B. longum H7-115. The evidence suggests that some heat-resistant somatic structures of B. longum can modulate a host's immune response at least via TLR2 expressed on intestinal epithelial cells.
{"title":"Anti-Inflammatory Effect of Bifidobacterium longum on Macrophage-Like THP-1 Cells via Epithelial Cell Caco-2","authors":"Reina Takisawa, Y. Nishitani, M. Mizuno, R. Osawa","doi":"10.12938/BIFIDUS.28.45","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.45","url":null,"abstract":"We examined the immunomodulation capability of Bifidobacterium longum strains via a Transwell co-culture system using human colonic epithelial cells, Caco-2, in the upper chamber, and human macrophage-like cells, THP1, in the lower chamber of the culture. Heat-treated cells of three B. longum strains, JCM1217 T , KT237 or H7-115, were added to the upper chamber to allow direct contact with Caco-2 cells and the culture was incubated for 24 hr. After incubation, THP-1 cells in the lower chamber were placed in a separate well containing fresh medium with LPS and incubated for 6 hr. After incubation, we found that TNF-α secretion from THP-1 cells, that had been co-cultured with Caco-2 directly contacting heat-treated cells of B. longum strains, especially H7-115, was suppressed. This was, however, not the case in an the almost identical experiment using B. longum cells killed under ultra-violet light (not heat-treated). We then blocked Caco-2 TLR2 with anti-TLR 2 antibodies in another co-culture experiment and found that blocking TLR2 canceled the indirect anti-inflammatory effect of B. longum H7-115. The evidence suggests that some heat-resistant somatic structures of B. longum can modulate a host's immune response at least via TLR2 expressed on intestinal epithelial cells.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"45-48"},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12938/BIFIDUS.28.45","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The safety of two probiotic bifidobacterial strains, Bifidobacterium breve M-16V and Bifidobacterium infantis M-63, was evaluated by single dose and 90-day repeated dose oral toxicity tests using rats. In the single dose oral toxicity test using 1.4 × 10 12 CFU/kg of B. breve M-16V or 3.2 × 10 11 CFU/kg of B. infantis M-63, there were no death and no abnormalities. In the 90-day repeated dose oral toxicity test using 2.3 × 10 11 CFU/kg/day of B. breve M-16V or 7.6 × 10 10 CFU/kg/day of B. infantis M-63, no death and no abnormalities in body weight, food consumption, water consumption, urinalysis, hematology, blood biochemistry, organ weights, and histophathological findings were observed. The acceptable daily intake (ADI) of B. breve M-16V was calculated to be 1.38 × 10 11 CFU/day for an adult weighing 60 kg and 1.15 × 10 10 CFU/day for an infant weighing 5,000 g. Based on the findings of the present study together with the taxonomy and distribution data, as well as clinical experience in preterm infants, B. breve M-16V may be considered as extremely safe for consumption by humans including infants. Although B. infantis M-63 was considered as safe as B. breve M-16V, further confirmation by clinical investigations may be required.
{"title":"Safety Evaluation of Two Probiotic Bifidobacterial Strains, Bifidobacterium breve M-16V and Bifidobacterium infantis M-63, by Oral Toxicity Tests Using Rats","authors":"F. Abe, T. Yaeshima, K. Iwatsuki","doi":"10.12938/BIFIDUS.28.7","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.7","url":null,"abstract":"The safety of two probiotic bifidobacterial strains, Bifidobacterium breve M-16V and Bifidobacterium infantis M-63, was evaluated by single dose and 90-day repeated dose oral toxicity tests using rats. In the single dose oral toxicity test using 1.4 × 10 12 CFU/kg of B. breve M-16V or 3.2 × 10 11 CFU/kg of B. infantis M-63, there were no death and no abnormalities. In the 90-day repeated dose oral toxicity test using 2.3 × 10 11 CFU/kg/day of B. breve M-16V or 7.6 × 10 10 CFU/kg/day of B. infantis M-63, no death and no abnormalities in body weight, food consumption, water consumption, urinalysis, hematology, blood biochemistry, organ weights, and histophathological findings were observed. The acceptable daily intake (ADI) of B. breve M-16V was calculated to be 1.38 × 10 11 CFU/day for an adult weighing 60 kg and 1.15 × 10 10 CFU/day for an infant weighing 5,000 g. Based on the findings of the present study together with the taxonomy and distribution data, as well as clinical experience in preterm infants, B. breve M-16V may be considered as extremely safe for consumption by humans including infants. Although B. infantis M-63 was considered as safe as B. breve M-16V, further confirmation by clinical investigations may be required.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"7-15"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12938/BIFIDUS.28.7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Ohashi, Ayako Andou, M. Kanaya, Keisuke Harada, T. Fujisawa
Hydrogen-utilizing bacteria in the feces of Japanese individuals were analyzed with the specific polymerase chain reaction targeting the functional genes. The formyltetrahydrofolate synthetase gene derived from acetogenic bacteria was predominantly detected in all subjects. We consider that reductive acetogenesis might be an important H 2 disposal pathway in healthy Japanese.
{"title":"Acetogenic Bacteria Mainly Contribute to the Disposal of Hydrogen in the Colon of Healthy Japanese","authors":"Y. Ohashi, Ayako Andou, M. Kanaya, Keisuke Harada, T. Fujisawa","doi":"10.12938/BIFIDUS.28.17","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.17","url":null,"abstract":"Hydrogen-utilizing bacteria in the feces of Japanese individuals were analyzed with the specific polymerase chain reaction targeting the functional genes. The formyltetrahydrofolate synthetase gene derived from acetogenic bacteria was predominantly detected in all subjects. We consider that reductive acetogenesis might be an important H 2 disposal pathway in healthy Japanese.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"15 1","pages":"17-19"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jasna Mrvčić, Damir Stanzer, V. Bačun-Družina, Vesna Stehlik-Tomas
Western diet is frequently low in essential metal ions. A common method for preventing metal ion deficiency is pharmacological supplementation, especially in a highly available form such as metalo-protein complexes. Accordingly, in this work, specific lactic acid bacteria were assessed for their ability to bind copper ions. Significant amounts of copper ions were bound, and the binding potential was found to be strain specific. Differences among the strains were evaluated with the Langmuir model for biosorption. Binding of copper was a fast process, strongly influenced by ionic strength, pH and biomass concentration. During the process, copper ions significantly reduced cell viability. Discharge of copper ions in a simulated gastrointestinal tract was examined ; 85-90% of copper ions bound to LAB were discharged in the gastrointestinal model system.
{"title":"Copper Binding by Lactic Acid Bacteria (LAB)","authors":"Jasna Mrvčić, Damir Stanzer, V. Bačun-Družina, Vesna Stehlik-Tomas","doi":"10.12938/BIFIDUS.28.1","DOIUrl":"https://doi.org/10.12938/BIFIDUS.28.1","url":null,"abstract":"Western diet is frequently low in essential metal ions. A common method for preventing metal ion deficiency is pharmacological supplementation, especially in a highly available form such as metalo-protein complexes. Accordingly, in this work, specific lactic acid bacteria were assessed for their ability to bind copper ions. Significant amounts of copper ions were bound, and the binding potential was found to be strain specific. Differences among the strains were evaluated with the Langmuir model for biosorption. Binding of copper was a fast process, strongly influenced by ionic strength, pH and biomass concentration. During the process, copper ions significantly reduced cell viability. Discharge of copper ions in a simulated gastrointestinal tract was examined ; 85-90% of copper ions bound to LAB were discharged in the gastrointestinal model system.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"28 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12938/BIFIDUS.28.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66339146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The role of the intestinal microflora in the development and correct functionality of the immune system is becoming increasingly evident. A perturbation of the gastrointestinal microflora or unwanted immune responses to this flora have been demonstrated to play a critical role in the pathogenesis of inflammatory bowel disease (IBD) in experimental animal models but recently also in tumorigenesis. It has been proposed to modify the intestinal microflora via the administration of probiotics in IBD patients. In order to better understand how probiotics could be beneficial to the host, it is important to understand how bacteria are handled at mucosal surfaces and how dendritic cells and epithelial cells communicate with each other to 'tolerate' the intestinal flora. This article is intended to summarize recent advances on the function of gut immune cells and on some of the features that have been documented on the immunophenotypic characteristics of some probiotic strains.
{"title":"Interactions between Epithelial Cells and Dendritic Cells in Bacterial Handling","authors":"M. Rescigno, E. Mileti","doi":"10.12938/BIFIDUS.27.113","DOIUrl":"https://doi.org/10.12938/BIFIDUS.27.113","url":null,"abstract":"The role of the intestinal microflora in the development and correct functionality of the immune system is becoming increasingly evident. A perturbation of the gastrointestinal microflora or unwanted immune responses to this flora have been demonstrated to play a critical role in the pathogenesis of inflammatory bowel disease (IBD) in experimental animal models but recently also in tumorigenesis. It has been proposed to modify the intestinal microflora via the administration of probiotics in IBD patients. In order to better understand how probiotics could be beneficial to the host, it is important to understand how bacteria are handled at mucosal surfaces and how dendritic cells and epithelial cells communicate with each other to 'tolerate' the intestinal flora. This article is intended to summarize recent advances on the function of gut immune cells and on some of the features that have been documented on the immunophenotypic characteristics of some probiotic strains.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"27 1","pages":"113-122"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66338400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitric oxide is produced by numerous cell types along the GI tract where it serves to regulate a variety of physiological processes including gut motility, secretions, mucosal blood flow and immunity. Classically, NO is produced from L-arginine and molecular oxygen by specific enzymes, the NO synthases, but more recently a fundamentally different pathway for NO generation was described. This involves stepwise reduction of the higher nitrogen oxides nitrate and nitrite to form NO. In this process commensal bacterial in the GI tract play a key role. Dietary nitrate (mainly provided for by vegetables) accumulates in saliva and the oral microflora reduces this nitrate to nitrite. Nitrite then enters the stomach where it is reduced to NO by the acid. A picture is now emerging suggesting an important role of entero-salivary circulation of nitrate and serial reduction to NO in regulation of gastric function. Intriguingly, the nitrite that survives gastric passage is absorbed and can later recycle to NO in blood and tissues via several enzymatic as well as non-enzymatic pathways. Such systemic NO generation is likely involved in regulation of cardiovascular function and tissue homeostasis, especially in response to ischemia and hypoxia.
{"title":"Nitric Oxide in the Gastrointestinal Tract: Role of Bacteria","authors":"J. Lundberg","doi":"10.12938/BIFIDUS.27.109","DOIUrl":"https://doi.org/10.12938/BIFIDUS.27.109","url":null,"abstract":"Nitric oxide is produced by numerous cell types along the GI tract where it serves to regulate a variety of physiological processes including gut motility, secretions, mucosal blood flow and immunity. Classically, NO is produced from L-arginine and molecular oxygen by specific enzymes, the NO synthases, but more recently a fundamentally different pathway for NO generation was described. This involves stepwise reduction of the higher nitrogen oxides nitrate and nitrite to form NO. In this process commensal bacterial in the GI tract play a key role. Dietary nitrate (mainly provided for by vegetables) accumulates in saliva and the oral microflora reduces this nitrate to nitrite. Nitrite then enters the stomach where it is reduced to NO by the acid. A picture is now emerging suggesting an important role of entero-salivary circulation of nitrate and serial reduction to NO in regulation of gastric function. Intriguingly, the nitrite that survives gastric passage is absorbed and can later recycle to NO in blood and tissues via several enzymatic as well as non-enzymatic pathways. Such systemic NO generation is likely involved in regulation of cardiovascular function and tissue homeostasis, especially in response to ischemia and hypoxia.","PeriodicalId":90114,"journal":{"name":"Bioscience and microflora","volume":"27 1","pages":"109-112"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66338296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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