Our attitude towards bacteria needs a rethink
“Bacteria” has been a bad word, spelling infections and diseases. But the latest Human Microbiome project has something different to say. What it says can change the way we look at ourselves and our ailments...and of course influence our attitude towards bacteria.
There are many sites and talks on this project but the one under review gives a comprehensive introduction to the project. On BBC radio, it comes as a conversation between Dr. Julie Segre, senior investigator at the U S National Institute of Health, Claire Fraser-Liggett, Director of the Institute for Genome Sciences at the University of Maryland, Lita Proctor Head of the project at National Institute of Health, and interviewer Geoff Watts.
The conversation gives us some statistics: Our body is the playground for around 100 trillion microbes, hiding in our mouth, nose, guts, skin and genitals. The Human Microbiome Project in the US is sequencing the genomes of bacteria which live on our body. The Microbiome project thinks that understanding the life that lives on the internal and external body surfaces could provide vital information on illnesses from heart diseases to cancer. Our microbes help us digest food in our stomach, produce natural moisturisers on our skin and synthesise vitamins in our intestine.
Julie Segre says, “The Microbiome project is a process of discovery. We need to start thinking of ourselves as super-organisms. This is the second genome – the bacterial genomes as well as the human genomes, all of that is part of the true genetic content of a human.”
The theory is that we have co-evolved with our microbes in order to defend our bodies against pathogens. Geneticists are aiming to find out what constitutes a healthy microbial community, and what happens when the group is invaded by ‘bad’ bacteria. New research has suggested that pathogenic microbes could be implicated in a whole host of diseases, including obesity, heart disease, cancer, Alzheimer’s, arthritis and autism. The sheer density of microbial cells is ten times more than the human cells on our body surfaces.
“We may find there are new links between the human microbiome and diseases that today we don’t think of as having any underlying microbial component,” says Claire Fraser-Liggett.
The hope is that this research will pave the way for more personalised treatments which could help get our bacterial communities get back on the right track. The Microbiome project sees any one person’s microbes as one community. So rather than studying them individually, they are studying the microbes and their genetic material collectively.
Lita Proctor says, “Microbes includes fungi, bacteria and viruses...we have still to identify all of them. We are aiming at understanding and sequencing 3000 of them. It sounds like a lot but we are probably looking at thousands of species of which we don’t know about.”
The process of extracting the genetic material from an entire community of project begins by dipping a swab taken from the body in salt water. The organisms released are then tested in many ways. The DNA is extracted from them and later mounted on to sequencing machines. The sequencing machine drills down to the base code.
A skin sample could have 500 microbes and each microbe could have four million of these little letters...this complicated analysis is being done so quickly only thanks to advances in technology.
“The key to this field is the new mathematical techniques to analyse this data,” says Lita Proctor. “What species is where and what are they doing? These are the questions we are engaged with....”
A European project found about two kilos of bacteria live in our gut. They help us digest food we can’t do ourselves and give some proteins and even help to prevent cancer. There are three different types of microbial community which may be related to diet and so different communities may have different microbial population.
As research on microbiomes progresses, the hope that new cures can be found gains strength.