Watersheds and Human Health

Water & Watersheds
Environmental & Science Education
Sustainability
Edward Hessler

Microbial cells overwhelm the number of human cells by about ten to one.  However they have only relatively recently received research attention.  A major project is the Human Microbiome Project.

The Human Gut Microbiome project preceded the Human Microbiome Project.  Its goal is to provide whole genome sequences for 100 species which are representative of the bacterial divisions known to reside in the distal gut (the descending colon) of humans.

Bacteria of the distal gut live in a very social network because some genes and stretches of genetic material are readily exchanged among various species.  This is often referred to as horizontal gene transfer which plays an important role in health.

Courtesy of Pacific Northwest National Laboratory.

A short essay in the New Yorker by Wudan Wu describes some extraordinary work by Ilana Brito who has a research interest in the movement of infectious diseases.  She was present at a talk by Stacy Jupiter of the World Conservation Society on a link, one I've not thought much about, between watershed health and human health.  This led her (almost) from lecture to airport to hop a plane to Fiji.

There, Dr. Brito studied the movement of bacteria between human communities as well as the movement of genes between various bacterial communities.  It is easy to miss the scale of Brito's undertaking.  The Human Microbiome Project involves hundreds of researchers as well as some thirty institutions.  Brito worked alone although later, back in the lab, colleagues were involved.

The research design included a survey of four villages and the collection in each villages of four samples--hand swabs, stool swabs, saliva and soil--over a period of six weeks. She also had to freeze them and keep them frozen during her stay.  You can learn how she managed that in Yan's essay (see below for the link).

Once home, she, with colleagues at the Massachusetts Institute of Technology genetically sequenced the samples.  Brito is now a member of the Biomedical Engineering Department at Cornell, becoming an assistant professor in July 2016.

In mid-July, Brito and 15 others published a paper in the British journal Nature on their findings.  The paper is protected by a paywall but the abstract may be read here.

Wudan Yan's lively essay notes one major finding, the role of diet on mobile genes.