meRfi®-GM
The Digital Textbook on Gut Microbiota and Beyond

The gut microbiota has changed significantly over the past 2000 years. Alfa-diversity has decreased in industrial populations compared to non-industrial populations
Olm & Sonnenburg 2021

The diversity of the intestinal microbiome in human palaeofaeces samples (1000-2000 years old) is closer to that of today's non-industrial population
Wibowo et al. 2021

The gut microbiota plays a role in mammalian growth, metabolism, behavior, and protection against infections.
Tremaroli & Backhed 2012 Nature 489: 242-249
Sommer & Backhed 2013 Nat. Rev. Microbiol. 11: 227-238
Brown & Clarke 2017 Immunology 150: 1-6
Morais et al. 2021 Nat Rev Microbiol 19: 241-255
Panwar et al. 2021 Genes Immun 22: 255-267

The murine and human mucosal-associated gastrointestinal microbiome and found it to only partially correlate with stool microbiome
Zmora et al. 2018 Cell 174: 1388–1405

The estimated ratio of human/microbiota cells was recently revised from 10 times to 1.3 times more than human cells
Ursell et al. 2012 Nutr. Rev. 70: S38-S44
Sender et al. 2016a Cell 164: 337-340

There are about 100 trillion symbiotic microbial cells in the human body
Sender et al. 2016

The entirety of microorganisms, bacteria and fungi residing in the gastrointestinal tract. The gut microbiota interacts with local and distant cells of the body via various mechanisms

The human gut hosts 500 to 1,000 microbial species on average
Knight & Buhler 2015 First TED Books hardcover edition. ed

The small intestine is rich in nutrients utilized by both the host and microbe for growth. Proteobacteria (mainly enterobacteria), Lactobacillales and Erysipelotrichales (especially Turicibacter) are dominant in the small intestine. In contrast, the large intestine is poor in such nutrients and therefore harbor much fewer numbers of these bacteria, while Bacteroidetes and Clostridia which can utilize host indigestible fibers as energy sources are enriched
Tap et al. 2009 Environ Microbiol 11: 2574-2584
Zoetendal et al. 2012 ISME J 6: 1415-26
Delgado et al. 2013 Microb. Ecol. 63: 763-772
Kamada et al. 2013a Nat Immunol. 14: 685-690
Walker et al. 2014 Trends Microbiol. 22: 267-274
Tuohy & Scott 2015 in: Diet-Microbe Interactions in the Gut, eds K. M. Tuohy and D. Del Rio (London: Elsevier), 1-15

The gut microbiota is an open microbial ecosystem composed of resident commensals continuously exposed to transient non-human microbes in the diet.
Veiga et al. 2015 Sci. Rep. 4: 6328

10^13 - 10^14 cells per gram content in Colon / Large Intestine and feces; 10^4 - 10^7 cells per gram content in jejunum and ileum
Candela et al. 2014 World J Gastroenterol 20(4): 908-922

The stomach and upper intestine have very low levels of microbial colonization as a result of acid and bile secretion in the stomach and duodenum and constant intestinal motility
Hooper et al. 2012

Bacterial diversity was estimated to exceed 400 culturable species and two archaeal methanogenic species were isolated from human faecal samples
Savage 1977 Annu. Rev. Microbiol. 31: 107-133
Miller et al. 1982 Appl Environ Microbiol 43: 227–232
Finegold et al. 1983 In Human Intestinal Microflora in Health and Disease. Hentges, D.J. (ed.). New York, USA: Academic Press, pp. 3–31

see also:
Bad Guys (certain harmful bacteria)
Brain-Gut-Microbiome-Axis / Gut-Brain Axis
Composition & Gut microbiota
Good guys (certain beneficial bacteria)
Gut microbiota & Metabolic activities / Metabolism
Gut microbiota & Pathobionts / Pathogens
Hermaphrodites
Industrialisation
Gut bacteria flora