Microbiota ecology

Queipo-Ortuno MI, Boto-Ordonez M, Murri M, et al. Influence of red wine polyphenols and ethanol on the gut microbiota ecology and biochemical biomarkers. Am J Clin Nutr. 2012 95 1323-1334. 

Tzounis X, Rodriguez-Mateos A, Vulevic J, Gibson GR, Kwik-Uribe C, Spencer JPE. Prebiotic evaluation of cocoa-derived flavanols in healthy humans by using a randomized, controlled, double-blind, crossover intervention study. Am ] Clin Nutr. 2011 93(1) 62—7Z Isabel Queipo-Ortuno M, Boto-Ordonez M, Murri M, et al. Influence of red wine polyphenols and ethanol on the gut microbiota ecology and biochemical biomarkers. Am J Clin Nutr. 2012 95(6) 1323—1334. 

For decades in aquatic ecology, the apparent chemical recalcitrance of humic substances that dominated the instantaneous bulk DOC of standing and running waters led to the belief that these compounds were poorly used by microbiota. To be sure, loss rates are slow, but consistently in the range of 0.5-2% per day under many different environmental conditions (Fig. 2). Often rates of degradation of total dissolved organic matter are greater than 2% per day. 

Espeland, E.M. and Wetzel, R.C. (2001) Complexa-tion, stabilization, and UV photolysis of extracellular and surface-bound glucosidase and alkaline phosphatase implications for biofilm microbiota. Microbial Ecology 42, 572-585. 

Bisson, I. A., Marra, P.P., Burtt, E.H., Sikaroodi, M., Gillevet, P.M. (2009). Variation in plumage microbiota depends on season and migration. Microbial Ecology 58, 212-220. 

Sekwatei-Monang, B., Valcheva, R., Ganzle, M. G. (2012). Microbial ecology of sorghum sourdoughs effects of substrate supply and phenolic compounds on composition of fermentation microbiota. International Journal of Food Microbiology, 159, 240-246. 

Vilela, D. M., Pereira, G. V. M., Eerreira Silva, C., Batista, L. R., Schwan, R. R (2010). Molecular ecology and polyphasic characterization of the microbiota associated with semi-dry processed coffee Cojfea arabica L.). Food Microbiology, 27, 1128-1135. 

We do not yet completely understand how the different environments and wide range of diets which modern humans around the world experience has affected the microbial ecology of the human gut. Gut microbial composition depends on different dietary habits just as health depends on microbial metabolism, but the association of microbiota with different diets in human populations has not yet been shown. The relative importance of genetic make-up and uptake of environmental microorganisms to provide humans with these fundamental microbial functions is still under debate. 

Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The analysis performed on the gut microbiota of humans living a modem lifestyle revealed that the microbial community is typical of omnivorous primates. ... 

Second, probiotics must be delivered at an effective dose. In the gut, the resident microbiota clearly outnumbers administered probiotic microorganisms and this may reduce the chances of probiotics having a major impact on the microbial ecology of the gut environment. A number of viable cells are required to be able to survive gastric transit, to resist the action of bile salts and then reproduce within the gut to ensure a colonization rate sufficient to provide the expected beneficial effects. 

As regards the gut microbiota, however, the ecological use of probiotics holds when the microbiota composition has been altered by external or internal factors, such as antibiotic treatments or inflammatory diseases. For this kind of application there is strong and convincing evidence of the usefulness of the probiotics. ... 

On the contrary, it seems extremely difficult to demonstrate the beneficial effect of probiotics administration to healthy adults, which are supposed to have a quite stable intestinal microbiota. We have to keep in mind that ecological niches such as the gut try to resist changes when they have reached homeostasis this attribute has been defined before as the "resilience" of the intestinal microbiota. 

While the impact of diet in shaping the composition of the gut microbiota is well supported by analytical data (for a review, see Ref. 90), it seems more difficult that a single bacterial strain and even a complex mixture of strains could significantly alter the overall pattern of the intestinal bacterial content, thus restricting the ecological use of probiotic to specific conditions of altered microbiota. 

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