AIM： In order to characterize the qualitative and quantitative microorganisms in different sites of the lower digestive tract （LDT） in healthy volunteers, a specific technique was developed for collecting mucous of...AIM： In order to characterize the qualitative and quantitative microorganisms in different sites of the lower digestive tract （LDT） in healthy volunteers, a specific technique was developed for collecting mucous of the distal ileum, colon and rectum. METHODS： A polyethylene tube was designed to go through the colonoscope channel with a No. 8 French tube. In order to avoid internal contamination, the distal extremity was protected with a membrane of microfilm after being sterilized in ethilene oxid. To facilitate the aspiration of a precise volume, its interior was coated with silicone. One hundred rnicrolliter （0.1 mL） sample of mucous was collected and transferred into an Eppenddorff tube containing nine hundred rnicrolliter （0.9mL） of VMGA-3 （viable medium of Goteborg）. This procedure was repeated at each site of the LDT with a new sterilized catheter. RESULTS： All sites revealed the ＂non pathogenic＂ anaerobic bacteria Veillonella sp （average 10s colony forming units/mL-CFU/mL）, allowing to conclude an environment of low oxidation-reduction potential （redox） in the LDT. It was also characterized the presence of Klebisiella sp with significant statistical predominance （SSP） in the ileum. Enterobacter sp was found with SSP in the sigrnoid colon, Bacteroides sp non-pigmented （npg） and Ecoli with SSP in the sigrnoid colon and rectum, Enterococcus sp and Lactobacillus sp with SSP in the rectum, all in a mean concentration of 10s CFU/mL CONCLUSION： This procedure is feasible and efficient and can point out a similar distribution of the aerobic and anaerobic bacteria with the presence of biological markers of normal microbiota in the LDT.展开更多
Aerobic anoxygenic phototrophic bacteria (AAPB) are characterized by the following physiological and ecological features. A mother AAPB cell can unusually divide into 3 daughter cells and looks like a 揧?during the di...Aerobic anoxygenic phototrophic bacteria (AAPB) are characterized by the following physiological and ecological features. A mother AAPB cell can unusually divide into 3 daughter cells and looks like a 揧?during the division. AAPB cells sometimes adhere together forming a free-floating population. Most of the known AAPB species are obligately aerobic. Bacteriochlorophyll a (BChl a) is the only photosynthetic pigment in AAPB, and the number of BChl a molecules in an AAPB cell is much less than that in an anaerobic phototrophic bacterial cell, while the accessorial pigments carotenoids in AAPB are abundant in concentration and diverse in species. In addition to the common magnesium containing BChl a, a zinc-containing BChla was also seen in AAPB. AAPB have light harvesting complexⅠbut usually lack light harvesting complexⅡ. Although AAPB featur in photosynthesis, their growth is not necessarily light- dependent. There is a mechanism controlling the photosynthesis approach. AAPB are widely distributed in marine environments especially in oligotrophic oceans accounting for a substantial portion of the total biomass and playing a unique role in the cycle of carbon and other biogenic elements. Besides the contribution to primary production, AAPB also have great potentials in bioremediation of polluted environments. Studies on AAPB would be of great value in understanding the evolution of photosynthesis and the structure and function of marine ecosystems.展开更多
文摘AIM： In order to characterize the qualitative and quantitative microorganisms in different sites of the lower digestive tract （LDT） in healthy volunteers, a specific technique was developed for collecting mucous of the distal ileum, colon and rectum. METHODS： A polyethylene tube was designed to go through the colonoscope channel with a No. 8 French tube. In order to avoid internal contamination, the distal extremity was protected with a membrane of microfilm after being sterilized in ethilene oxid. To facilitate the aspiration of a precise volume, its interior was coated with silicone. One hundred rnicrolliter （0.1 mL） sample of mucous was collected and transferred into an Eppenddorff tube containing nine hundred rnicrolliter （0.9mL） of VMGA-3 （viable medium of Goteborg）. This procedure was repeated at each site of the LDT with a new sterilized catheter. RESULTS： All sites revealed the ＂non pathogenic＂ anaerobic bacteria Veillonella sp （average 10s colony forming units/mL-CFU/mL）, allowing to conclude an environment of low oxidation-reduction potential （redox） in the LDT. It was also characterized the presence of Klebisiella sp with significant statistical predominance （SSP） in the ileum. Enterobacter sp was found with SSP in the sigrnoid colon, Bacteroides sp non-pigmented （npg） and Ecoli with SSP in the sigrnoid colon and rectum, Enterococcus sp and Lactobacillus sp with SSP in the rectum, all in a mean concentration of 10s CFU/mL CONCLUSION： This procedure is feasible and efficient and can point out a similar distribution of the aerobic and anaerobic bacteria with the presence of biological markers of normal microbiota in the LDT.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.40232021,40176039 and 30170189)the National Key Basic Research and Development Program(Grant Nos.2001CB409700 and G2000078500).
文摘Aerobic anoxygenic phototrophic bacteria (AAPB) are characterized by the following physiological and ecological features. A mother AAPB cell can unusually divide into 3 daughter cells and looks like a 揧?during the division. AAPB cells sometimes adhere together forming a free-floating population. Most of the known AAPB species are obligately aerobic. Bacteriochlorophyll a (BChl a) is the only photosynthetic pigment in AAPB, and the number of BChl a molecules in an AAPB cell is much less than that in an anaerobic phototrophic bacterial cell, while the accessorial pigments carotenoids in AAPB are abundant in concentration and diverse in species. In addition to the common magnesium containing BChl a, a zinc-containing BChla was also seen in AAPB. AAPB have light harvesting complexⅠbut usually lack light harvesting complexⅡ. Although AAPB featur in photosynthesis, their growth is not necessarily light- dependent. There is a mechanism controlling the photosynthesis approach. AAPB are widely distributed in marine environments especially in oligotrophic oceans accounting for a substantial portion of the total biomass and playing a unique role in the cycle of carbon and other biogenic elements. Besides the contribution to primary production, AAPB also have great potentials in bioremediation of polluted environments. Studies on AAPB would be of great value in understanding the evolution of photosynthesis and the structure and function of marine ecosystems.
