Biotics, Part II

Biotics, Part II

    With all this talk of antibiotics and bacteria and microbes and microbiomes, it might be time for a bit of clarification.  To begin with, our bodies have trillions of cells, but only about 10% of those are ours, that is, human cells; the rest (yes, that's 90% of the 100 trillion or so cells within us*) belong to the microbes.  So does that mean bacteria?  Partially yes.  Here's a better definition from Microbe World: Microbe is a term for tiny creatures that individually are too small to be seen with the unaided eye.  Microbes include bacteria, archaea, fungi and protists...Archaea are bacteria-like creatures that have some traits not found in any true bacteria.  Protists include primitive algae, amoebas, slime molds and protozoa...Without microbes, we couldn’t eat or breathe.  Without us, they’d probably be just fine...There are more of them on a person's hand than there are people on the entire planet!.  And bacteria are small...in their example, if the smallest microbe (a virus) was the size of a baseball, a bacteria would be the size of the pitcher's mound...a human cell would be the size of the entire ballpark.  Life began with these microbes some 3.5 billion years ago; upright humans have yet to be here on earth for a quarter of million years (that just over 1/10 of 1%).

    Bonnie Bassler, a biologist from Princeton, has been running controversial experiments with bacteria, elevating them from primitive single-celled organisms to ones that maintain an intricate communication network.  In an interview by Casandra Willyard in Discover, Dr. Bassler said: At first, the quorum scientists had trouble getting others to believe that bacteria could speak within their species.  And then we came forward with this idea that they could talk across species — lots of people thought I was nutty...What they first do is they scan the environment.  And they’re asking the simplest question: “Am I alone or am I in a group?”   They just look for any quorum-sensing molecule.  Then, the more sophisticated question that I think they ask is, “Who is that?”  They can say, “You are my absolute identical twin.”  They can say, “You’re my extended family.”  And then they say, “You’re some other species.”  They’re not just counting.  There’s information encoded in these molecules that tells a bacterium who that neighbor is — how related they are.  And depending on the ratio of those three molecules, they understand whether their family is winning or losing...Having that information is extremely useful for decision-making.  Bacteria aren’t just swimming around.  They live adhered to surfaces.  Your skin, your scalp, your intestines — they’re all covered in communities of bacteria, called biofilms.  In order to make a biofilm, they have to secrete this substance that glues them all together, which acts like a shield.  That’s controlled by quorum sensing. 

    If it all sounds a bit loopy to you, imagine bacteria in all of its forms (at least, those that we know about), from bioluminesence to eating dangerous chemicals, from breaking down organic matter to producing their own antibiotics (the actinomycetes do this).  And for the most part, we are waging a war on all of them.  Each time we use antibacterial soap or (worse) antimicrobial soap, we flush away "germs" but more importantly, add the chemical arsenal to the water supply which allows other bacteria to develop a resistance to it.  This happens when we take antibiotics as our excretions add even more to the water and waste supplies.  Throw in the animal feed and we're creating ever-stronger mutations of bacteria; new studies indicate that our surge in allergies, obesity and other diseases might all be related to this quest for sterility.  As one experiment on the ISS (International Space Station) is showing, a place where everything from water to air is thoroughly filtered of all microbes, astronauts are returning with compromised immune systems.  Said a piece in Popular Science: Microbes appear to have prospered by making themselves incredibly useful, and we’ve gladly given up space in exchange for the vitamins, digestive enzymes, and­ meta­bolites they provide.  And so the discovery that the urban gut harbors up to 40 percent less microbial diversity than that of indigenous people living in a remote jungle concerns scientists.  These “missing microbes,” they say, may have been decimated by several decades of industrial­ized foods, which limited our diets, and antibiotic use, which extended our lives at the expense of theirs.

    Enter the age of "pro" biotics, currently a $30 billion industry and steadily growing, much of it without proof of efficacy.  Some studies are showing that adding the billions of live bacteria cultures (common in some yogurts, although many of the more commercial yogurts only feature a single strain; search for brands such as Nancy's or Brown Cow or Mountain High in the U.S, yogurt brands which contain five or more active bacteria cultures), may prove little more than a drop of a drop of a drop in the bucket.  An approach being more promoted is to get back to basics...gardening in the soil without gloves, washing with ordinary soap, and letting your dog or cat give you that occasional lick.  

    None of this has delayed the "destroy" research which continues on bacteria; Wired featured a short summary of some of the current alternatives, from Crispr gene-editing systems which attack a bacteria's DNA to aiding bacterial toxins called bateriocins.  The short piece somewhat jokingly begins: Damn bacteria. The wily things keep mutating, developing resistance to antibiotics.  Another piece in Popular Science said "The Age of Antibiotics is Over," and highlighted phages and phage enzymes and peptides (the short piece does a better job of explaining each of these old viruses and enzymes; phages have been in popular use in countries once part of the Soviet Union, partially due to an inability to get antibiotics, partially leading to the EU's Phagoburn now in its final year of human studies).

    So after all of this, what does one do?  Perhaps one tactic might be to take away the all-encompassing title of bacteria.  As with an alien species encountering a hostile human military, it would be difficult to explain to the aliens that humans are composed of all sorts, good and bad, hostile and peaceful, angry and compassionate.  Don't lump us all together we might say.  And bacteria might be saying the same thing to us.  Since our cells make up just 10% of our bodies (the microbes inside us weigh twice as much as our brains), maybe it's time we listen to the majority, the other 90% that are the microbes and the bacteria.  Before you next wash your hands, take a quick look at them and think back to the words posted earlier, that there are more microbes there --just on your hands-- than there are humans on this planet.  War or peace, antibacterial soap or a plain bar of soap, billions of pieces of life undisturbed or all-out destruction?  A simple beginning, a simple decision...

*Yes, the ratio of microbes to human cells is continually debated and is sometimes treated as a random ratio based on earlier fecal studies.  But even the most recent research has the range of human cells from a low of 15 trillion to a high of over 400 trillion so even those figures aren't agreed upon...I've stayed with the earlier ratio of 1 human cell to every 10 microbes.