How microbes affect you from brain to bowel

From Cosmos Magazine, September 5-9, 2016. (Photo: Lactobacillus casei by AJC1 via Flickr)

Not a day goes by without some new study proclaiming the importance of our microbes to our health. It’s hard to keep up, and hard to sort the wheat from the chaff, the mildly interesting association from the water-tight causal link. I recently wrote a five part series that looks at the current state of microbiota research – what evidence is solid, and what needs further investigation.

Microbes and you: a partnership millions of years old

We are not alone. Our bodies are teeming metropolises of microscopic life – and the microbes that call us home influence everything from bowel to brain.

Over the past decade, technological advances in the lab have allowed us to take a census of our microbial entourage – known as the microbiota – like never before. Instead of seeing only the small fraction of microbes from our skin or poo that blossom on a petri dish, we can now blend, extract and read the genetic essence – the DNA – of all microbes, called the microbiome, to get a better idea of who’s there.

The picture that has emerged is one of staggering complexity. Read more…

How bugs in your gut can make you fat (or thin)

Tinkering with gut microbes causes more than a tummy ache. They can wring more calories from food and boost fat cell production – all from day one.

By far the majority of our companion microbes, weighing an impressive 1.5 kilograms and containing more than 1,000 species, reside in our gut, mostly in the large intestine.

As soon as a baby is born – and perhaps even before – microbes move in. Many are seeded from bacteria in the mother’s birth canal if it’s a vaginal birth or from her skin if it’s a caesarean birth. Read more…

Microbe tenants help – and hinder – your immune system

Obesity isn’t the only condition linked to imbalanced gut microflora. A host of autoimmune and inflammatory conditions – inflammatory bowel disease, coeliac disease, multiple sclerosis, rheumatoid arthritis and lupus – are also associated with changes to gut microbial ecosystems.

(Indeed, obesity is often described as an inflammatory condition for the widespread immune reaction that accompanies excess weight.)

Connecting the dots between altered gut microbes and disease is a lively area of research. Scientists are working on the ‘chicken or egg’ problem: does disrupting the gut microflora cause the disease, or does having the disease lead to changes in gut microflora?

In many cases, it is likely that a complex interplay between genetics and environmental triggers – including the microbes in our guts – is involved. Read more…

Mood, mind and memory – can gut bacteria meddle with the brain?

The microbes in your gut may be tiny, but their influence appears to extend as far as the brain, affecting mental health, stress levels, memory and cognitive abilities. Yet many of the most compelling results illustrating the microbiota-gut-brain axis, as it has become known, have only been seen in animals.

The potential for gut microbes to affect mood is probably best illustrated by an experiment conducted at McMaster University in Canada. Mice devoid of a microbiota were effectively given ‘personality make-overs’ via poo transplants. Timid mice became more brazen, and once daring mice retreated into shyness, taking on the anxiety profiles of their donors.

Human-to-rodent poo transplants also work. Read more…

Bugs as drugs – medicine’s next frontier

Microbiome research is providing tantalising clues about how we might change our microbiota to improve our health. But translating findings from the lab into clinical treatments is a slow and arduous process.

The most dramatic illustration of how our microbiota can be used in the clinic is the case of the poo transplant, also known as faecal microbiota transplantation. Read more…


Gut harmony: Why the right mix of microbes is important to our health

We are not alone. Each of us is teeming with bacteria and other microbes. From the soles of our feet to the follicles on our head — and every crevice in between — trillions of microbes form specialized ecosystems collectively known as our microbiota. The microbes that live on and in us outnumber our own cells by more than ten to one.

Far from being mere freeloaders, many of our microscopic passengers are essential residents — friendly bacteria that help us to digest our food, synthesize vital nutrients such as vitamins, and keep pathogens at bay. The rapidly growing field of microbiota research is starting to generate some tantilising results, linking our microbiota to everything from our weight, to our moods and behaviour.

But how is it that our microbes influence our health? How does our own behaviour — our diet and lifestyle — change our microbial ecosystems? And could we one day start to treat illnesses by manipulating our microbial communities?

In the latest episode of Up Close I spoke with a world expert in the field of microbial ecology. Professor Rob Knight is from the Department of Chemistry and Biochemistry, the BioFrontiers Institute, and the Howard Hughes Medical Institute, all at the University of Colorado, Boulder. Listen to the podcast or download the transcript here.

Speaking from the gut for immune health

B0007180 Villi from the small intestine
Villi from the small intestine (Photo credit: wellcome images)

Intestinal cells communicate with probiotic gut microbes for a healthy immune system

The human body is swarming with bacteria and other microbes that outnumber our own cells by more than ten to one. From the soles of our feet to the follicles on our head and every crevice in between, trillions of microbes form specialized ecosystems collectively known as our microbiota. Far from being mere freeloaders, many of our microbial ecosystems are comprised of essential residents – friendly bacteria called commensals. In the gut, these microbial allies help us to digest our food, synthesize vital nutrients such as vitamins, and keep pathogens at bay.

They also speak to us. By listening to the chemical chatter of our microbial lodgers, epithelial cells that line the inner surface of our gut can distinguish friend from foe.

Learning to decipher the chemical cacophony is critical to the development of a healthy immune system, and when the system breaks down, debilitating conditions like inflammatory bowel disease can take hold.

It turns out that our microbes are listening to us, just as much as we are listening to them. And according to a team of Finnish researchers, the dialogue between us and our microbes changes the way that both of us behave. Continue reading “Speaking from the gut for immune health”

Caring and sharing: captive wallaby microbes share genes with keepers’ microbes

Petrogale penicillata ; Featherdale Wildlife P...
Brush-tail rock wallabies — an endangered species (Photo credit: Wikipedia)

Each of us is home to a complex ecosystem of microbes that took up residence on or in us as soon as we emerged from our mother’s womb. In fact, our passage to the outside world — whether via vaginal birth or C-section — makes a significant contribution to the  bacteria, fungi and viruses that become our constant life companions. Collectively, they are known as our microbiota, and by the age of three, the ecosystems that we harbour on every patch of skin and turn of the intestine are very similar to those of our parents.

While it may not be surprising that parents share microbes with their kids, researchers at Macquarie University in Sydney have found that animal handlers may be sharing their microbes with their furry captive charges. In doing so, keepers working in captive breeding programs could be unwittingly releasing more back into the wild than they had planned. Top on the list of unintended releases are antibiotic resistance genes.  Continue reading “Caring and sharing: captive wallaby microbes share genes with keepers’ microbes”

Poo transplants on Ockham’s Razor

A couple of weeks ago I recorded a piece for Ockham’s Razor, a program that airs on Radio National in Australia. I’ve written about fecal transplants before (for Cosmos online, and the The Conversation), but radio is possibly my all-time favourite medium for learning about… well, stuff… anything, really. So, I pitched the poo story to Ockham’s Razor, and the final product aired on Sunday morning. Being slightly longer than my other pieces on the topic, I also managed to cover a little bit more on the microbiome, which was really the whole reason I started writing about poo in the first place! The transcript has also been reproduced, so you can either read or listen.

Ecology of the Nether Region

English: Lactobacillus organisms and vaginal s...
Lactobacillus organisms (purple) and vaginal squamous epithelial cells (pink). (Photo credit: Wikipedia)

The world of ecology has just got a whole lot more interesting. Instead of delving deeper into the uncharted waters of our oceans, or the dark recesses of the world’s rainforests, scientists have turned their focus inwards, to the ecology of microbes lurking in the nooks and crannies of our own bodies.

Incredibly, bacterial cells that live on and in us outnumber our own cells by about 10 to 1. Collectively known as the microbiome, these microscopic passengers are far from simple free-loaders. Our gut is teaming with bacteria that help us to digest everything from our breakfast cereal to our midnight ice-cream indulgence.

They’re a diverse bunch, too, and each particular niche that our body provides harbors a different community. Our skin, for example, is covered with an assortment of critters – there’s one community behind our ears, another living on the tips of our fingers, and still another nestled amongst the hair of our underarms. Continue reading “Ecology of the Nether Region”