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1、文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。1.Origin of prevalent claims in the literature on the number of bacterial cells In humans文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。为什么大家会普遍认为肠道微生物数量是人体细胞的十倍，本文作者对文献进行了追溯，结果显示1977年Savage,annu,Rev.Microbiol引用超过一千。而它的计算基础是胃肠道容积为1L，肠道微生物浓度为1011 /g.文档仅供参考，不能作为科学依据，请勿模仿
2、；如有不当之处，请联系网站或本人删除。文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。2.Distribution of bacteria in different human organs文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。不同部位的微生物数量相差很大，由上表可知，人体微生物约90%都集中 在结肠。所以作者统计了不同文献的结肠微生物浓度，平均值为0.92*1011/g.文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除
3、。3.Concentration of bacteria in the colon文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。4.The number of human cells in a“standard”adult male A mass-based order-of-magnitude estimate for this number assumes a 10 2 kg man,which is divided by the mass of a“representative”mammalian,cell 10-12-10-11 kg(assuming
4、cell volumes of 1,000-10,000 m 3,spectively),thus arriving at 10 13-10 14 cells.One study used a DNA-centered method(Baserga,1985).The method begins by estimating the number of cells in the body of a 25g mouse by dividing the total amount of DNA(stated to be 20 mg)by the DNA content of one diploid m
5、ouse cell(610-12 g DNA per cell)to get 310 9 cells in a 25 g mouse.Then extrapolate from mouse to human by using the ratio of masses to get 10 13 cells in the human body.This method excludes cells that do not contain DNA,such as red blood cells and platelets.Summing over a total of 56 cell categorie
6、s(Bianconi et al.,2013)resulted in an overall estimate of 3.710 13 humancells in the body(SD 0.810 13,i.e.CV of 22%)文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the bodyWe focus on the six cell types that were recently identified(Bianconi et al.,2013)to comprise 97%of
7、 the human cell count:red blood cell accounting for 70%),glial cells(8%),endothelial cells(7%),derma fibroblasts(5%),platelets(4%)and bone marrow cells(2%).The other 50 cell types account for the remaining 3%.文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the bodyRed bl
8、ood cells:(Boer,1984;Feldschuh and Enson,1977;Nadler et al.,1962;Snyder et al.,1975)4.9L(Ambayya et al.,2014;Dosoo et al.,2012;Nordin et al.,2004;Pekelharing et al.,2010;Volkmer and Heinemann,2011;Wakeman et al.,2007)5.010 12 cells/L(SEM 1.2%,CV 7%)(SEM 1.6%,CV 9%)This led to a total of 2.510 13 red
9、 blood cells(SEM 2%,CV 12%)This is similar to the earlier report of 2.610 13 cells(Bianconi et al.,2013).文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the bodyglial cells:The number of glial cells was previously reported as 310 12 (Bianconi et al.,2013)estimate is base
10、d a 10:1 ratio between glial lls and neurons in the brain.However,a recent analysis(Azevedo et al.,2009)revisits this value andafter analyzing the variation in between brain regions concludes that the ratio isclose to 1:1.The study concludes that there are 8.510 10 glial cells(CV 11%)in the brain an
11、d a similar number of neurons and so we use these values here.文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the bodyendothelial cells:The number of endothelial cells in the body was earlier estimated at 2.510 12 cells(CV 40%),by taking the mean surface area of one endo
12、thelial cell(Bianconi et al.,2013)and dividing it into the total surface area of the blood vessels,based on atotal capillary length of 810 9 cm.We could not find a primary source for the totallength of the capillary bed and thus decided to revisit this estimate.We used data regarding the percentage
13、of the blood volume in each type of blood vesse(Leggett and Williamst,1991).Using mean diameters for different blood vessels(Burton,1954)we were able to derive the total length of each type of vessel(arteries,veins,capillaries etc.)and its corresponding surface area.Dividing bythe mean surface area
14、one endothelial cell(Fltou,2011)we derive a totalestimate of 610 11 cells文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the body dermal fibroblast:The number of dermal fibroblast was previously estimated to be 1.8510 12(Bianconi et al.,2013),based on multiplying the tot
15、al surface area of the humanbody(SA=1.85 m 2(Herman,2007)by an areal density of dermal fibroblasts(Randolph and Simon,1998).The dermis is composed of two main layers:papillary dermis(about 10%of the dermis thickness)and reticular dermis(the other 90%)(McGrath et al.,2004).2.6 10 10 cells.文档仅供参考，不能作为
16、科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。5.Updated inventory of human cells in the body文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。6.Mass centered approach as sanity check for cell countFor a reference man mass of 70 kg,25%is extracellular fluid(Shen et al.,2007),another7%is extra-cellular solids(Shen et al.,2007),th
17、us we need to account for 47 kg of cell mass(including fat).文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。作者对人体的细胞数量进行了重新估计，84%为红细胞（质量2.5Kg），5%为血小板；脂肪占0.2%（质量13Kg），肌肉细胞占0.001%（质量20Kg）。文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。7.The ratio of bacteria to human cells in the adult body文档仅供参考，不能作为科学依据，请勿模仿；如有不当之处，
18、请联系网站或本人删除。8.Discussionwe think that updating the ratio of bacteria to human cells from 10:1 or 100:1 tocloser to 1:1 does not take away from the biological importance of the microbiota.Yet,we are convinced that a number widely stated should be based on the bestavailable data,serving to keep the quantitative biological discourse rigorous.经过重新估计后肠道微生物细胞数量与人体细胞数量之比由10:1变为1:1.作者指出不过这个比例是10:1，1:1，还是100:1都不影响肠道微生物重要的生物学意义。不过本着严谨的态度，应该用更详细可靠的数据。