Turicibacter

The gut microbiome of a pre-Columbian Andean mummy looks much different than our own

A photo of the mummy whose microbiome was studied

A photo of the mummy whose microbiome was studied

The study of ancient humans’ microbiomes is a topic of growing interest, because it is believed that these microbiomes more closely resemble native or ‘natural’ microbiomes than the ones we have today.  There have been a few studies on humans’ microbiomes at different periods of history, and another data point was added to the list last week.  Researchers from Italy and California were able to measure the microbiome of a pre-Columbian human (11th century to be exact) that was mummified naturally after he died in the cold, harsh, and high elevations of the Andes Mountains in Chile.  The researchers published their findings in the journal PLoS ONE.

The researchers sequenced the bacteria that were in the mummy’s colon, as well as the mummy’s feces.  Strikingly, around 99% of the bacteria belonged to the Firmicutes genus, mainly dominated by Clostridia, and Turicibacter.  In addition, the human appeared to have many bacteria associated with modern day diseases.  For example the mummy’s microbiome contained Clostridium difficile (the cause of C. difficile infection), Trypansoma cruzi (the cause of Chagas’ disease), and many types of human papilloma virus (HPV).  Finally, the researchers noted that many genes associated with antibiotic resistance were found in the mummy’s microbiome, long before these antibiotics were introduced.

This paper revealed many fascinating aspects about our ancient microbiomes.  First, it is interesting to see that Firmicutes dominated our ancient flora, especially because Bacteroidetes, which are much more common in our guts today, are broadly associated with health.  Also, it appears that many of the pathogens that afflict all sorts of diseases today have prehistoric counterparts, and may have been more abundant, or even more tolerable long ago.  Finally, the revelation about antibiotic resistance genes show that the mutations that cause them appear common enough that they occurred naturally in thousand year old colons.

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The views expressed in the blog are solely those of the author of the blog and not necessarily the American Microbiome Institute or any of our scientists, sponsors, donors, or affiliates.

Microbiome influenced by forced versus voluntary exercise in mice

A team of scientists led by researchers at the Mayo Clinic recently discovered that forcing mice to exercise led to exacerbated inflammation, whereas allowing the mice to exercise voluntarily attenuated inflammation.  They hypothesized that the gut microbiome may be responsible for this rather peculiar phenomenon, so they repeated the study, this time measuring changes in the microbiome.  They published their results in the Journal of Applied Physiology.

The scientists separated 29 mice into three groups, a group that was forced to exercise for 40 minutes per day, a group that voluntarily exercised, and a sedentary group that did not exercise.  They conducted their study over 6 weeks, after which the mice were euthanized and their microbiomes sampled.  The researchers discovered that even though each of the groups gained approximately 10% body weight over the course of the study, their microbiomes deviated.  Interestingly, the mice that voluntarily exercised, those same mice that attenuated inflammation, had the lowest gut microbiome diversity (a trait normally related to dysbiosis and illness).  On the genus level, Mollicutes, which has been associated with ulcerative colitis, and Nauatilia were elevated in the feces of mice forced to exercise.  In addition, Turicibacter, which is related to various organisms associated with IBD, was actually decreased in the mice that voluntarily exercised.  Beyond these loose associations though, the exercise’s impact on the microbiome was not clear.

Exercise can change the microbiome, and the authors suggest that the total amount of exercise between the voluntary and forced exercise groups may have been important, as it was not controlled in this study.  Strangely, in humans, excessive exercise and no exercise at all have both been linked to gastrointestinal issues like diarrhea and constipation.  Unfortunately, the authors did not study whether the mouse version of Jillian Michaels trainers constituted forced, or voluntary exercise. 

Please email blog@MicrobiomeInstitute.org for any comments, news, or ideas for new blog posts.

The views expressed in the blog are solely those of the author of the blog and not necessarily the American Microbiome Institute or any of our scientists, sponsors, donors, or affiliates.