The military hospital of Constantine, Algeria was a fitting place to view what must have seemed the Devil in microscopic form.
Stages of the malaria parasite drawn by Alphonse Laveran
Posted in Arts, History, Microbes, Visualization
Tagged biology, disease, history, malaria, microbes, mosquito, parasites, protozoa, visualization
Large lymphocyte from a normal blood film
One of my favorite essays by the immunologist-poet, Miroslav Holub, describes the symphony of cellular life enacted after a muskrat drowns in the writer’s pool and is shot by a neighbor. The scene itself is grim yet fairly boring and commonplace; dead animals, be it a robin flown into our window or a white-footed mouse decapitated by our cat, seem to be an ordinary part of suburban life. But Holub views the situation from the interior view of the animal and with the sense and extrapolation of a poet. His interest in the phenomenon of death lies in the cellular process that are taking place long after we conceive of the animal as “dead.” While ordinarily we see the spectrum of alive to dead as having a definitive moment of change from A to B, a universe of interactions, an ecosystem of cellular bodies, continues to communicate, move, exist. I’ve copied my favorite excerpt from the essay, that of the lymphocytes (an immunologist’s specialty), below.
So there was this muskrattish courage, an elemental bravery transcending life.
But mainly, among the denaturing proteins and the disintegrating peptide chains, the white blood cells lived, really lived, as anyone knows who has ever peeked into a microscope, or anyone knows who remembers how live tissue cells were grown from a sausage in a Cambridge laboratory (the sausage having certainly gone through a longer funereal procedure than blood that is still flowing). There were these shipwrecked white blood cells in the cooling ocean, millions and billions of them on the concrete, on the rags, in the wrung-out murkiness. Bewildered by the unusual temperature and salt concentration, lacking unified signals and gentle ripples of the vascular endothelium, they were nevertheless alive and searching for whatever they were destined to search for. The T lymphocytes were using their receptors to distinguish the muskrat’s self markers from nonself bodies. The B lymphocytes were using their antibody molecules to pick up everything the muskrat had learned about the outer world in the course of its evolution. Plasma cells were dropping antibodies in various places. Phagocyte cells were creeping like amoebas on the bottom of the pool, releasing their digestive granules in an attempt to devour its infinite surface. And here and there a blast cell divided, creating two new, last cells.
Posted in Excerpts, Literature, Microbes, Visualization
Tagged biology, immunology, literature, microbes, microcosm, Miroslav Holub, nature, umwelt
I am concerned about the use of the police and war metaphor in immunology; you can have a look at my previous post. I find it very difficult to think outside of this specific box. We are taught immunology with this metaphor. We told to communicate about immunology with this metaphor. I have the feeling that I face a wall when I try to think differently.
When you try to avoid the political extremism of this metaphor, it is difficult not to go into an other extreme, into a caricature of the opposite position. Indeed, we could be tempted by a peace and love metaphor (ref 1), but this would be such a caricature.
I chose here to take a political direction to give an example of a way to rethink the metaphor. I agree that science should avoid politics. But today for the sake of thinking outside of the…
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Many good articles have been published on the use of metaphor in science and in particular in biology (ref 1&2).
I will try to sum up a few questions about the metaphors used in immunology following the discussion of the conference given by Michel Morange at IHPST.
First, what are the metaphors used?
– The metaphor of the immune system being endowed with the mission of a police, or to make war : Indeed words such as “defence”, “attack”, etc…. are very frequently used. Even if immunologist will answer that they are aware that it is a metaphor, I am worried about the effect of such large use. Even if the metaphor may be discussed by the community, this does not appear to the general public that is only exposed to this war or police metaphor. One example shows that it is even the way of presenting immunology that is…
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While on the topic of host-parasite interactions, I recommend looking through an interesting science research blog, The Parasite Diary. There’s a trend in the blogosphere toward “research blogging.” While most science blogs tend to discuss scientific research in some way or another, research blogging (www.researchblogging.org) aims specifically to discuss, in detail, and without lessening analytic rigor, the results of the peer-reviewed literature in a given field. The Parasite Diary takes this approach as pertains to classic parasitology: studies examining life cycles, pathogen interactions with the host immune system, systematics–in other words, a good deal of interesting lab-based research to examine life from the parasite’s point of view.
Just a welcoming sentiment from Robert M. Sapolsky in his collection of science essays, Monkeyluv. Sapolsky is a professor of biology and neurology at Stanford, and his essays, often humorous, delve into neuroscience, hormones, and human behavior. Oliver Sacks has called him “one of the best scientist-writers of our time,” and while I wouldn’t put Sapolsky on the same pedestal as I do Gould, or Levi, or Thomas when it comes to prose and insight, the man certainly has his moments, which manifest in me dog-earring a corner of a page. This one stood out to me this morning on the 3 train to work while reading an essay titled ” Bugs on the Brain.” As someone who gets excited over pathogenic protozoa and animal behavior, I muttered “Toxoplasma gondii” upon seeing the heading.
Like most people who come across any mention of Toxoplasma (it gets a fair amount of press; e.g., via Carl Zimmer), Sapolsky is interested in the precision of how the protozoa can manipulate behavior. The organism relies on a simple and common two-host system to complete its life cycle: the predator-prey interaction of rodent and cat. Rodents ingest the protozoa, which encysts in the mammal, with particular affinity for denning in the brain. When rodents are consumed by felines, Toxoplasma can reproduce, new organisms are shed through feces, which happen to be a food source for rodents and thus how the life cycle comes full circle. Many pathogens that rely on multiple hosts influence behavior, and there is a bevy of literature that describes just this, particularly with tapeworms. In the case of Toxoplasma, the protozoa interferes with a rodent’s natural aversion to feline pheromones; interferes is a weak term–the organism makes the rodent attracted to feline odor, increasing the probability that it becomes successful prey.
What interests Sapolsky so about this host-parasite interaction is that a rodent infected with Toxoplasma gondii otherwise behaves normally. As he notes, infected rodents maintain their social status within the system’s hierarchy, they continue to mate and thus sense pheromones of the opposite sex, and their recognition of other vertebrate odors isn’t tampered with in the least. The protzoa is simply able to manipulate the recognition of and reaction to the pheromones of one predator, that of the definitive host. To Sapolsky (and most of us interested in the long-term interplay between parasites and their host), this is evidence of how counter-intuitive and beautiful evolutionary process can be. Sapolsky takes the opportunity to highlight Toxoplasma gondii as a correction to teleological interpretations of evolution: its processes aren’t directional, aren’t progressive. As he notes, “We are certainly not the most evolved species around, nor the least vulnerable. Nor the cleverest.” But the punctum of his message, to borrow a term from Roland Barthes (that which “pierces” the viewer/reader), is the statement, “we need phylogenetic humility.”