thyrotropin receptor In ecosystems such as rainforest

In ecosystems such as rainforest, all species are not created equal. The tall trees are the “foundation species” as they cover the forest to create a unique environment for all other species to thrive (Prevey et al., 2010). It is an interesting question whether a microbial ecosystem in a healthy human gut would also have its “foundation species”. In this study, we found not only overall structural changes of the gut microbiota but also significant changes of specific predominant species such as the enrichment of the genome of a carbohydrate-fermenting species B. pseudocatenulatum in response to the intervention. It is a major member of GIG3, which significantly increased after intervention. This bifidobacteria-dominated GIG showed negative correlation with several other GIGs containing potentially detrimental species. The “bifid shunt” pathway gives bifidobacteria growth advantages over other thyrotropin receptor fermentation bacteria by producing higher amount of acetate and producing more ATP from the same amount of available sugars (Pokusaeva et al., 2011). Species in GIG3 may work as “foundation species” to define much of the structure of a healthy gut ecosystem by rendering the gut environment unfavorable to pathogenic and detrimental bacteria, possibly via increased production of acetate and lactate (Ellison et al., 2005; Gibson and Wang, 1994). As such foundation species may become a powerful probiotic candidate for recovering and maintaining a healthy gut microbiota, this question warrants further exploration. The gut microbiota may impact host health by producing toxic bacterial metabolites such as TMA and indole and delivering them into the bloodstream. However, the specific members of the gut microbiota that produce these detrimental compounds remain largely unknown, particularly in humans. In a previous “proof of principle” study of a healthy human cohort, we showed that changes in the population levels of individual bacterial species in the gut can be correlated with changes of specific metabolites in the urine to reveal “who does what in the microbiome” (Li et al., 2008). In this study, we correlated changes in the population levels of individual bacterial genomes in the gut with changes of specific metabolites in the urine to reveal “which genome does what function in the microbiome” (Li et al., 2008). Several bacterial genomes that correlated with TMAO and indoxyl sulfate levels in the urine were found to encode genes for production of their precursors by fermentation of choline or tryptophan in the gut. This opens the possibility of getting pure isolates of these key bacterial genomes for further mechanistic studies.
Conclusion The following are the supplementary data related to this article.
Author Contributions
Acknowledgment This work was supported by the grants from the National Natural Science Foundation of China (31330005, 81100632, 31121064, 20825520, 81401141 and 21221064); the Ministry of Science and Technology of China (2010CB912501); the Science and Technology Commission of Shanghai Municipality (14YF1402200) and the National Science and Technology Major Project of China (2012ZX10005001-009). A computing facility award on the PI cluster at Shanghai Jiao Tong University is acknowledged. We thank Prof. Zhu Chen from Shanghai Center for Systems Biomedicine for his insightful discussion and guidance in designing the experiment.
Introduction The global burden of neonatal and child mortality is alarmingly high in low and middle income countries (LMICs). There has been a sharp decline in mortality rates in children under five years of age between 1990 and 2013 (from 90 mortalities per 1000 down to 46 mortalities per 1000 live births between 1990 and 2013). This rate needs to further decrease, to just 30 mortalities per 1000 live births, in order to meet the Millennium Development Goals (MDGs) 2015 target (You et al., 2013).