Category: Microbes

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Fermented diversity

Luigi’s post on The glut of bugs in your gut opened a window here on a neglected aspect of biodiversity: the bacteria associated with certain foods and those associated with digesting that food. In all the background murmuring about probiotics and prebiotics, I’ve been hearing a lot of good sense from Seth Roberts. He’s the self-experimenter who devised the Shangri-La Diet (which isn’t a diet but a way of regulating appetite) and of late he’s been blogging more and more about fermented foods.

The things Roberts has noted are plentiful and diverse — I won’t summarize them here — but I can say that I’ve yet to meet a fermented food, in the widest sense, that I didn’t like. I also like playing with a few ferments myself. Of course there are fermentation fanatics, not just for the process as a whole but for particular “miracle mushrooms” and the like. ((To which, naturally, I have no intention of linking.)) And that puts some peoples’ backs up. But there is also probably a lot of good sense in making use not only of a diversity of ingredients, but also in a diversity of ways of processing them, outside and inside the body.

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The glut of bugs in your gut

A long article on The Why Files discusses changing attitudes to the human gut flora:

These critters, mainly bacteria, vastly outnumber the cells in our bodies, and we are utterly dependent on them. Bacteria make vitamin K, essential for clotting blood. As they do in cows, bacteria play an essential role converting our food into usable chemicals. And bacteria form a complex barrier against invading pathogenic microbes.

The realization of which has led to an explosion of proper scientific work on probiotics ((“Live microorganisms which when administered in adequate amounts confer a health benefit on the host,” according to the WHO.)), formerly confined to the lunatic fringe.

A springboard for the growing interest, Huffnagle ((Gary Huffnagle, professor of internal medicine and microbiology at the University of Michigan Health System.)) says, was a discovery by Jeffrey Gordon of Washington University, who found that bacteria “can talk to the epithelial cells that line the GI tract, which can turn on different genes depending on who is living nearby.”

What’s the connection to agrobiodiversity? More from the article in The Why Files:

Probiotics can be taken in supplement pills, or in many cultured products, such as yogurt, cottage cheese, tempeh and kefir. It’s not clear which mechanism is better, says Sanders ((Mary Ellen Sanders, executive director of the International Scientific Association for Probiotics and Prebiotics.)), who consults to the dairy industry on microbiology. “Often probiotics are incorporated into the production of a food product, but we don’t really have a good sense of how important that might be. During the fermentation of milk into a dairy product, they may … produce organic acids or peptides that contribute to the health effects of a probiotic yogurt, but unfortunately there is no good research to sort out the benefits of a fermented dairy product versus a dry supplement.”

So microbial agrobiodiversity doesn’t just result in a huge range of delicious products with strong niche market potential. It’s also good for you.

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Bedbugs redux

Caveman Forecaster is a blog about “the art and science of time series analysis and forecasting.” There was a post about a month ago about bedbugs that really piqued my interest. It seems that bedbugs (Cimex lectularius) were virtually eradicated in the US fifty years ago, but are making a comeback. That has even led to the organization of a National Bedbug Summit, which took place last month. The post was mostly about using Google search data to monitor and predict the seasonal outbreaks and longer-term trends. But it got me looking into the reasons for the resurgence, and wikipedia has a reasonable summary of that, with plenty of references. Basically, genetic diversity studies suggest that there was never complete eradication, but that the pesticide-resistant populations moved to alternate hosts, “have slowly been propagating in poultry facilities, and have made their way back to human hosts via the poultry workers.” So here’s another example of a human pest which can also hang out with agrobiodiversity, and jump back and forth.

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Diversity on air

I’ve been listening to a radio programme about diversity in action. Called The Evolution Boomerang, from Soundprint, it examines three cases where diversity is important to agriculture and the environment. There’s a segment on GMO cotton and insect resistance, a segment on the need for genetic diversity at salmon hatcheries, and a segment on selecting bacteria to degrade a chemical that had never existed on Earth before humans manufactured it.

All good stuff, if you have half an hour to spare. You will need Real Player to listen.