Friday’s Featured Organism: Vibrio fischeri

Vibrio fischeri


I love all living things (in a total non-hippy way), but it’s clear that I’ve my preferences, and prokaryotes don’t get as much coverage as Eukarya around here usually. So here’s a bacterium, and what’s cooler than a normal bacterium? A bacterium that glows in the dark. Yes, Vibrio fischeri is a gram-negative marine bacterium, widely studied for its bioluminescence. Not only it lights up, but it’s also capable of symbiosis with marine animals like fishes and squids, which use its bioluminescence to their own advantage, and have co-evolved with these bacteria so that it’s easier for the microorganisms to colonize specific organs in their bodies. As far as I know, it’s also used in ecotoxicology studies, probably in part because it should be easier to check the growth of a glowing bacterium than the growth of a non-shiny one.

Awesome microbiologist saves the life of old, fat italian rockstar and gets funds for research

This is absolutely irrelevant to most people, especially non-italian readers, but I’ve just learned that a couple of weeks ago University of Bologna’s professor Davide Zannoni, who was my teacher of General Microbiology last year, contributed to helping old, fat, drug-addicted italian rockstar Vasco Rossi out of an infection which had plagued him for many months. Rossi, remembered for his songs but also for idiotic acts like trying to sue the italian version of Uncyclopedia for defamation, rewarded the effort by donating 75.000 that will fund a 3 years research program on microbial biofilms (I guess he was crying inside a little bit, thinking of how much drug he could have bought for himself instead – but then he did the right thing). Biofilms are a stage in the life cycle of many bacteria during which the single cells stop living an isolated, planktonic life and instead aggregate on a solid surface, creating a complex structure of polysaccharides that keeps them togheter and attached on the substrate, while allowing liquids to flow in and out through various canals. This way not only the colony can stay in a favourable habitat, but it’s also protected by many dangerous substances, including antibiotics and toxic metals. If a biofilm of dangerous bacteria forms in the human body (like it happened on Rossi’s heart), getting rid of it is extremely difficult: only free bacterial cells can be attacked, but the biofilm will persist, and after the treatement it will usually release more free cells in the organism, again and again. Zannoni’s goal is to find a way to inhibit the biochemical communication between bacterial cells, which is the tool bacteria use to regulate the growth and behaviour of a colony as it was a single organism (I’ve already mentioned this ability in an old article). This would disrupt the colony’s capability to coordinate and create biofilms, thus making the destruction of the bacteria much easier. Based on my experience, I can say that Zannoni is a great teacher and microbiologist, and a very intelligent man. I wish him and the other researchers success in their research, and I hope many will follow Vasco Rossi’s example and donate to scientific research, because the world needs it, and my country needs it more than ever.

P.S. The story (in italian, of course) is here.

Friday’s Featured Organism: Pyrococcus furiosus

Pyrococcus furiosus

Goodness, gracious, great balls of fire!

Pirococcus furiosus! The “furious ball of fire”! Probably one of the most badass name in the binomial nomenclature. The little guy is an Archaea, a group of unicellular organisms that look like Bacteria and yet are more closely related to Eukarya (us… and algae, and moss, and roaches, and amoebas…). Most Archaea are extremophiles, living only in extreme conditions that would be deadly for most other organisms, and P. furiosus, as the name implies, just likes it hot: it grows between 70 °C and 103 °C, to be precise. Its DNA polymerase, the Pfu DNA polymerase (and the polymerase of other thermophiles, like the Taq polymerase of Thermus aquaticus, a Bacteria) is used in PCR (if you don’t know what it is, it’s a widely used technique to amplify a sequence of DNA generating millions of copies of it) because the repeated high temperatures used in this technique would deactivate a normal DNA polymerase.

The Hive Mind

by Francesco Lami

To quote Bender from Futurama, “I’m back, idiots!”. It was a nice little holiday on the Cote d’Azur, but right now I want to talk about brains. Our brains, specifically.

At the beginning of the summer I had read on some generic weekly magazine a small paragraph about how some scientists thought that human beings pushed the evolution of intelligence to its limits: in other words, they said that we couldn’t become smarter, because we peaked. My first thought was “Yeah, bullshit” because that wasn’t a scientific magazine, and it seemed like the classical vague anthropocentric article about how we are the best, and the somehow intended ending of the evolutionary project. And let me clarify this, as awesome as we are, we’re not THE best. There’s not such a thing as the absolute best in evolution. Some organisms are more adaptable than others, some have better instruments to survive in a specific habitat or more habitats (and mind you, the habitat can always change), but we’re just a small, successfull and still evolving (as every living thing) branch of the enormous Tree of Life. There are many species of bacteria, arthropods, worms, fungi, etc… that are much more successfull than us, so while our species is clearly one of the most successfull vertebrates EVER, it’s by far not the most successfull organism of all time. But I digress.

What I could concede to that small paragraph was that certainly in modern times the selective pressure necessary to “push us” to an even superior intelligence is pretty low. We were able to create awesome technology and modificate our environment to make survival easier, and in our (western) society everybody can access at least the most basic of those advantages; the creations of smart people are enjoyed by everyone, and thus smart people and less smart people have the same chances of survival. But this didn’t convince me that we didn’t have at least the potential to evolve in something smarter.

Anyway,the last issue of Le Scienze (italian name of Scientific American) contained an article about the fact that we may have indeed reached the limit of intelligence for a single organism, and I guess it was the same article referenced in that small paragraph I had read months before. Actually the article (by Douglas Fox) suggests that, while there might be ways to improve our brains, the costs in terms of energy and space (remember the joke about planet sized heads? yeah, you don’t want one of those) would be too high to justify them, so the modern version of our brain might be the near-perfect, most functional compromise. I don’t know if this is true, but certainly this is an explanation that I can accept better than “We’re so awesome, nothing can beat us”: after all, physical limits like this are the cause of many “imperfections” in the world of biology. Organisms are not magical, and even when they adapt the best they can to their environment, they must still obey its laws, and the laws of the matter they’re composed of. As Stephen Jay Gould pointed out, the best evidence for evolution isn’t the perfect adaptation, but these small imperfaction caused by the fact that life must build new forms from the parts it already has – it can’t start again from blank to create better components for a completely new organisms.

While the focus of Fox’s article are the details about the limits that prevent us from becoming smarter, it concludes briefly hypothesizing a way in which humanity could become more intelligent, and the most promising tool to realize this ideal is – brace for it – the Internet! HA, suck it, Internet haters.

The point is that certain organisms that act in a pretty “stupid” way individually form colonies which have a much better decisional ability and can act in an extremely efficient way for their own survival. The most famous example of this are social hymenopterans like ants and bees, insects that embody the definition of eusociality: the labor is divided among specialized castes (queen, males, workers, warriors… it depend on the species) and every individual is actually just a small part of the entire, huge, collective organism, just like a single cell is just a small functional part of a body or a brain. And it’s this collective entity that takes decisions and shows complex behaviours. Other eusocial animals include termites (Isoptera) and even mammals like the nightmarishly ugly and yet strangely fascinating Heterocephalus glaber, the naked mole rat. And animal eusociality is not the only, or even the first, example of  organisms cooperating to “become smarter”: bacteria do that too. Everybody knows bacteria are single-celled organisms; most of them however form colonies capable of feats that are impossible for isolated bacterial cells. Bacteria colonies can decide if the environmental conditions and resources would allow them to grow (quorum sensing) and coordinate their metabolism thanks to special biomolecules used by the cells to communicate with each other; they can form biofilms in favourable environments, to protect and anchor themselves; colonies of Rhodospirillum centenum are capable of phototaxis (they are photosyntetic bacteria that move towards the light source) while single cells of the same species are incapable of doing so.

So the point is that, even though we are animals with a strong individual personality (well, some of us are, at least), we’re still social animals, and communication can make our population smarter and more efficient than the sum of its parts. We do this since the dawn of our species, with spoken words, and then written words, and now we can do it globally thanks to the internet. The fact that shared knowledge is a lot more vast than the knowledge of a single man is obvious, as it’s obvious that labour division and coordination made us a lot more efficient in a lot of different tasks. Are we really going to become a single planetary superintelligent supercolony? Would this really be an advantage to us? Nowadays individualism and egoism are rampaging everywhere, and so it may seem highly unlikely, and to some even scary, the possibility that society will prevail on the individual, and yet globalization and mass communication make us march everyday towards that possibility. We’ve already prooved to be strange animals: big primates who give birth only a few times in their lifetime (K strategy) and yet we managed to become one of the most widespread mammals on the planet, thanks to our intelligence and cooperation. So it may be possible the paradox of the animal with the most complex individual personality that, while retaining said individuality, becomes part of a global coordinated hive mind. I don’t know how far this process will go, if it’ll be enough to save us from ourselves and if it will influence our biological evolution. What I know is that, while some people think that globalization is evil, to me it only means that everyone in the world will have access to the same medicines. So what the hell, let’s give it a shot.