AIM: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. METHODS: A novel CEC: bacteria co-culture system was used to compa...AIM: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. METHODS: A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E coli(SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production. RESULTS: Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion.E coli induced production of MIP-1α/β and p defensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2α expression, respectively. TNFa, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion. CONCLUSION: These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo.展开更多
A series of laboratory screening tests have been performed with the objective of evaluating the effect of feed rate, screen length and screen motion on the quality of separation. The separation performance has been ev...A series of laboratory screening tests have been performed with the objective of evaluating the effect of feed rate, screen length and screen motion on the quality of separation. The separation performance has been evaluated by the use of proposed ISO Standard measures which are based on the partition curve.The laboratory rig, the test programme and results derived from it are discussed. The effect of screen length, feed rate and screen motion on the levels of screen performance as indicated by these measures and a normalised separation size parameter are discussed in relation to the assumed screening conditions for the tests reported and conclusions are summarised.展开更多
A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and r...A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and results derived from it are discussed. Suggestions for future work with the objective of assessing the industrial significance of the research to the optimisation and design of screening processes are presented.展开更多
基金Supported by the USA Public Health Service grants AI-41562 and POI RR12211 (SRC and PF)the Ann Gloag Fellowship of the Royal College of Surgeons Edinburgh and The Rays of Hope Charitable Trust (JS)
文摘AIM: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. METHODS: A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E coli(SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production. RESULTS: Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion.E coli induced production of MIP-1α/β and p defensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2α expression, respectively. TNFa, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion. CONCLUSION: These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo.
文摘A series of laboratory screening tests have been performed with the objective of evaluating the effect of feed rate, screen length and screen motion on the quality of separation. The separation performance has been evaluated by the use of proposed ISO Standard measures which are based on the partition curve.The laboratory rig, the test programme and results derived from it are discussed. The effect of screen length, feed rate and screen motion on the levels of screen performance as indicated by these measures and a normalised separation size parameter are discussed in relation to the assumed screening conditions for the tests reported and conclusions are summarised.
文摘A series of laboratory screening tests have been performed with the objective of evalu-ating the effect of feed rate, screen length and screen motion on the quality of separation achieved. The statistic analysis and results derived from it are discussed. Suggestions for future work with the objective of assessing the industrial significance of the research to the optimisation and design of screening processes are presented.
