Posts tagged: biology
Food guru Michael Pollan has picked up on the “we’re more bacteria than human” meme and written an long, impressive New York Times article about it. He doesn’t go so far as to bring up the theory that oil is actually the excrement of bacteria that live beneath the earth’s crust, not the decomposed organic matter from the surface, as suggested by Thomas Gold (and apparently some unnamed Russians). If Gould is right then humans not just city-suits for bacteria, but also a waste disposal system for bacteria. This idea led Reza Negarestani to obliquely postulate that global warming will actually function to make the surface of the earth hot enough for those particular bacteria to live on the surface of the earth as well. Which means we’re doing, like, triple duty for our bacterial masters.
No, Pollan doesn’t go into any of that weird shit. He’s more practical, writing instead about the role that bacteria has in our health. For example, obesity, heart disease and other health issues may depend on what kind of gut bacteria we’re carrying around. Of course this reminds me of the 90s gene craze (“the obesity gene,” the “addiction gene,” the “wearing white socks with dress shoes gene”) and the 00s neuroanatomy craze. The upside is that a bacteria-focused model of health is less fatalistic than the genetic or neuroanatomical models — you can change your bacteria, you can’t change your genes. But there’s plenty of room for woo and quackery and unfulfilled promises. That’s not lost on bacteria researchers. Pollan writes:
My first reaction to learning all this was to want to do something about it immediately, something to nurture the health of my microbiome. But most of the scientists I interviewed were reluctant to make practical recommendations; it’s too soon, they told me, we don’t know enough yet. Some of this hesitance reflects an understandable abundance of caution. The microbiome researchers don’t want to make the mistake of overpromising, as the genome researchers did. They are also concerned about feeding a gigantic bloom of prebiotic and probiotic quackery and rightly so: probiotics are already being hyped as the new panacea, even though it isn’t at all clear what these supposedly beneficial bacteria do for us or how they do what they do. There is some research suggesting that some probiotics may be effective in a number of ways: modulating the immune system; reducing allergic response; shortening the length and severity of colds in children; relieving diarrhea and irritable bowel symptoms; and improving the function of the epithelium. The problem is that, because the probiotic marketplace is largely unregulated, it’s impossible to know what, if anything, you’re getting when you buy a “probiotic” product. One study tested 14 commercial probiotics and found that only one contained the exact species stated on the label.
That didn’t stop Pollan from seeking out a little bit of practical advise, which mostly consists of: eat a variety of fiber sources, don’t load up too much on processed foods, relax a little about hygiene and eat pre-biotics like kimchi, sauerkraut and yogurt.
On two species of humanoids in HG Wells’ The Time Machine — Eloi and Morlocks — Edward Strickson writes:
So, is it likely that this is our future? We can speculate, but I’d lean pretty far towards a no. As we combine our cultures and try to spread equality, it’s less likely that entire branch of us will be isolated, unless there is a natural disaster or something similar that separates us. But this does not mean that we will not change, just that the extremes of Eloi and Morlocks are (thankfully) looking less likely as time goes on, at least in my point of view.
The historic tendency of “masters” to have sex with slaves may also prevent our evolution from ever bifurcating along class lines.
Strickson thinks that of the two species we’re more likely to end up like the Eloi: “Many more of us are able to get on with our lives without immediate dangers, knowing that if anything befalls us we will be looked after.”
I disagree. Modern medicine has licked a number of diseases, and increased our likelihood of surviving accidents. Yet our lives are not without immediate dangers. We risk death every day in the U.S. when we step into automobiles. The rest of the world face other dangers, ranging from war lords to malaria. We still have no cure for AIDs, which is still one of the most common causes of death in world.
Meanwhile, global warming is baking our planet, necessitating more adaptation and/or evolution. Perhaps the Morlocks, with their underground habitats, are our species’ future after all.
They’re built out of old CD-ROM drives, recycled ink cartridges and a open source Arduino boards. So far I think they just print bacteria? From the InkJetBioPrinter page:
We’ve disassembled an abandoned HP 5150 inkjet printer for use as a bioprinter. So far, we’ve pried open some ink cartridges, filles the black cartridge with arabinose, printed the BioCurious logo on filter paper, put the paper on a lawn of pGLO E. coli, and watched our logo light up in GFP!
Check out some pics on our Flickr group here: http://www.flickr.com/groups/bioprinter
Next, we want to start printing live cells, starting with E. coli. We’ll probably print the cells on a sheet of filter material and put it onto an agar plate, or pour a thin, dense layer of agar on a support material, and feed that into the printer directly. We’ll see…
(via H+ Magazine)
Still playing catchup:
An intriguing new long-term study of Filipino men has discovered that becoming a father lowers a man’s testosterone level. More specifically, what really drops male testosterone is the amount of time spent caring for children; men who spent three hours or more per day caring for a child had significantly less testosterone than those dads who were less involved with their children. It’s not that men with lower testosterone were “naturally” more inclined to be caregivers in the first place; based on the voluminous longitudinal data, it’s the act of caring itself that reduced testosterone significantly.
An otherwise reasonable New York Times piece on the study begins with the somber warning, “This is probably not the news most fathers want to hear.” But as several researchers in the article point out, this is actually great news for dads—and for all men. One of our great enduring myths about males is that we are biologically hardwired for violence and promiscuity, and that any attempt to encourage us to take on a nurturing, tender role is destined to end in failure. The “Caveman Cult” crowd, which includes a great many popular writers on gender, suggests that female physiology is optimized for caregiving while male physiology is optimized for conquest. And when pressed to cite the chief factor in this supposed male inability to care for children, these defenders of traditional gender roles almost invariably cite the overarching influence of testosterone.
The BBC reports:
Anthropologists have discovered three human fossils that are between 1.78 and 1.95 million years old. The specimens are of a face and two jawbones with teeth.
The finds back the view that a skull found in 1972 ago is of a separate species of human, known as Homo rudolfensis. The skull was markedly different to any others from that time. It had a relatively large brain and long flat face.
But for 40 years the skull was the only example of the creature and so it was impossible to say for sure whether the individual was an unusual specimen or a member of a new species.
With the discovery of the three new fossils researchers can say with more certainty that H.rudolfensis really was a separate type of human that existed around two million years ago alongside other species of humans.
Technology Review covers Stuart Kauffman’s work to find a mathematical model for autocatalytic sets, the process by which life may emerge from molecules:
What makes the approach so powerful is that the mathematics does not depend on the nature of chemistry—it is substrate independent. So the building blocks in an autocatalytic set need not be molecules at all but any units that can manipulate other units in the required way.
These units can be complex entities in themselves. “Perhaps it is not too far-fetched to think, for example, of the collection of bacterial species in your gut (several hundreds of them) as one big autocatalytic set,” say Kauffman and co.
And they go even further. They point out that the economy is essentially the process of transforming raw materials into products such as hammers and spades that themselves facilitate further transformation of raw materials and so on. “Perhaps we can also view the economy as an (emergent) autocatalytic set, exhibiting some sort of functional closure,” they speculate.
Could it be that the same idea—the general theory of autocatalytic sets—can help explain the origin of life, the nature of emergence and provide a mathematical foundation for organisation in economics?
(via Social Physicist)
I find this very interesting, but don’t get too excited. These sorts of grand unification theories are extremely elusive. I’m also skeptical of these sorts of models which try to find universal rules for all types of systems.
Krista and Tatiana Hogan are conjoined twins joined at the head. But unlike all other known craniopagus twins the Hogans’ brains are also linked, by a small bridge connected the thalamus of one girl to the thalamus of the other. Susan Dominus wrote for The New York Times last year:
Suddenly the girls sat up again, with renewed energy, and Krista reached for a cup with a straw in the corner of the crib. “I am drinking really, really, really, really fast,” she announced and started to power-slurp her juice, her face screwed up with the effort. Tatiana was, as always, sitting beside her but not looking at her, and suddenly her eyes went wide. She put her hand right below her sternum, and then she uttered one small word that suggested a world of possibility: “Whoa!”
From Wired UK:
The researchers found that thrill-seeking is not limited to humans and other vertebrates. The brains of honeybees that were more likely than others to seek adventure exhibited distinct patterns of gene activity in molecular pathways known to be associated with thrill-seeking in humans.
The findings present a new perspective on honeybee communities, which were thought to be highly-regimented and comprised of a colony of interchangeable workers taking on a few specific roles to serve their queen. […]
Robinson and his team studies two behaviors that looked like novelty seeking: scouting for new nest sites and scouting for food. When a colony outgrows its living quarters, the swarm must hunt for a new home. Around five percent of the swarm goes hunting for new lodgings. These “nest scouts” are around 3.4 times more likely than their peers to also become food scouts, researchers discovered.
“There is a gold standard for personality research and that is if you show the same tendency in different contexts, then that can be called a personality trait,” Robinson said.
(via James Governor)
Photo by Gilles San Martin
“These slices were sectioned and mounted at the University of Iowa, after MR imaging at the University of Illinois.”
Interesting column at Better Humans by James J. Hughes. A biological approach to thinking about love and sex:
Not just lust, but the amorphous ball of feeling called “love” itself is a biochemical phenomenon, amenable to manipulation. In Anatomy of Love, anthropologist Helen Fisher summarizes research arguing that love is composed of three biochemical process. The first process, driven by testosterone, is lust. The second process, infatuation, is controlled by dopamine, norepinephrine and phenylethylamine — amphetamine-like chemicals that produce feelings of euphoria. The lust and infatuation chemicals peak after a year, and for the lucky few relationships that survive their decline a new biochemical response emerges based on oxytocin, vasopression and endorphins, which produce feelings of intimacy, trust and affection.
(via Three River Tech Review)