Feb 132015
 

A few years ago, I looked in a sample of water from a bog lake, and saw something like a hyperactive avocado shifting around inside in a tiny kerosene lamp:

The architect of that pretty dwelling is the ciliate Calyptotricha pleuronemoides. The species and genus were discovered in 1882, in samples from a pond near Hertford, England, by an amateur naturalist named Frederick W. Phillips.  Not much is known about him.  During the 1880s, he was an active member of the Hertfordshire Natural History Society and Field Club, to whom he occasionally read essays on “The Protozoa of Hertfordshire,” based largely on the classification scheme in William Saville Kent’s Manual of the Infusoria.  He was a Fellow of the Linnean Society of London, and he found and named a few new taxa.

In his very first glimpse of the creature, Phillips was lucky enough to catch it in the act of building its lorica. “At first sight,” he writes, “I thought it was an embryonic or encysted stage of some monad; but upon applying a magnifying power of some 900 diameters, I observed that it possessed a singular vibratile membrane, closely resembling that which characterizes the members of the family Pleuronemidae.” A week later, Phillips looked at it again, and discovered that “the lorica had increased in size, and that one end was elongated into a teat-like form.” At this stage, he accidentally allowed the sample to dry out, leaving the organism’s empty, half-finished lorica still attached to a strand of pond-weed. He made a nice drawing of what he’d seen.

Calyptotricha pleuronemoides from Phillips resized

A. First stage B. The same, further developed C. End view of lorica D. The perfect animal E. Ventral view (adapted from Phillips)

To modern readers, accustomed to the impersonal, passive style of scientific writing–“samples were collected,” “living cells were isolated and observed”–there is something pleasingly candid about the way Victorian naturalists report their findings. Phillips doesn’t just describe his new genus, he spins us the tale of its discovery, including the mishap that destroyed his first specimen, and his initial misreading of the oval shell, after which he takes us to the very moment of discovery when he exposed the creature’s true nature by “applying a magnification of 900 diameters.” Something about that reminds me of the exploration literature of the same period. It’s probably not just an accident of style: Victorian microscopists were explorers. Superior lenses and stains had opened up a miniature Dark Continent on their laboratory benches, and a gentleman adventurer from somewhere like Hertfordshire could now penetrate these hidden realms, returning with breathless accounts of what he had seen. A session at the microscope was an expedition into the unknown.

In our time, researchers are expected to pile up some data before going to print, and nobody would attempt to erect a new ciliate genus on the basis of a brief observation of a few specimens. No doubt that is a good thing: the 19th century left a big legacy of poorly defined taxa, many of which are still desperately in need of revision.  But this kind of field work, as sketchy and dilettantish as it might seem now, has largely been put to one side without really being replaced by anything better.  Outside of a few centers of activity, ciliate field work has slowed to a crawl.  Consider the fact that 132 years after Phillips wrote his three-page note on Calyptotricha pleuronemoides it is still one of only two substantial treatments of the species, and the only source that describes the construction of its curious lorica.  Anyone who wants to know more about this ciliate than its name, has to travel back to the 19th century.

poke bonnet

A straw poke-bonnet, from the early 19th century. (Click for source)

Needless to say, the old information is not always reliable.

Phillips perceived immediately, and rightly, that Calyptotricha is closely related to the more common ciliate Pleuronema. Like its cousin, it is equipped with a large, billowing membrane that runs along the right side of its oral aperture. However, Phillips badly misunderstood the shape of this structure, describing it as “a membranous trap, or velum, which in form resembled the old-fashioned poke-bonnet.”

When I first read that passage, the comparison to a “poke-bonnet” confused me. The undulating membrane of pleuronematid ciliates is shaped something like a sail, or a flag: a sheet of fused cilia running along one side of the organism’s mouth. Phillips, however, interpreted this structure (which, admittedly, is very difficult to see clearly in the light microscope) as a sort of hood or canopy covering the oral aperture of the ciliate. If you look closely at his illustration, you can see that he has drawn it as a baggy tube.

Calyptotricha's undulating membrane resembles a sail or banner (image adapted from Colin R. Curds, British and Other Freshwater Ciliated Protozoa)

The true shape of Calyptotricha’s undulating membrane (image from Colin R. Curds, British and Other Freshwater Ciliated Protozoa, with arrows added)

Evidently, it was this imagined resemblance to a poke-bonnet that prompted him to give the genus its curious name, Calyptotricha, constructed from the Greek calyptos (“veiled” or “covered”) and trich (“hair”). It seems the “haired” holotrichous ciliate reminded him of a woman’s head, on top which the membrane sits like an old-fashioned hat!

It’s an example of how expectation shapes observation. In interpreting this membrane as an enclosed hood, he was deferring to an earlier error by his illustrious contemporary William Saville Kent. Writing about Pleuronema, Kent says: “[T]his membranous trap may be appropriately compared with the extensile hood of a carriage or an outside windowshade forming, when expanded, a capacious hood-shaped awning, and when not in use being packed away in neat folds close around the animalcule’s mouth.”

The “extensile hood” Kent mentions was a common convenience on carriages of his day, and provided a compelling mechanical analogy for the “neat folds” with which he imagined Pleuronema pulled back its velum.

Barouche image 2Here, for comparison, is Kent’s illustration of Pleuronema chrysalis, which I’ve inverted to showcase its “extensile hood.”

Pleuronema chrysalis, from W. S. Kent's A Manual of Infusoria. Put wheels on it, and you have a chuck wagon.

With wheels, it would make a good chuck wagon.

To modern workers familiar with the morphology of hymenostome ciliates, as revealed in specimens that have been stained with silver, this is an implausible design. However, to Kent, who had done pioneering work on choanoflagellates, it seemed reasonable to speculate that Pleuronema’s hood might share “a distant homological relationship” with the “delicate funnel-shaped membranes” found in the collared flagellates, which really do wear something a bit like a straw poke-bonnet (but on the back end of the cell).

Finally, since we’ve been talking about Pleuronema and her sisters, I’ll post some footage of one, quietly browsing on bacteria in water taken from a tidal pool on the coast of Maine:

REFERENCES

Nov 182013
 

I used to study English Literature.  I did that for a decade and a half, at two universities, and eventually wrote a doctoral thesis on “Postwar American Poetry.”  In all the years I spent researching poetry,  nobody ever asked me why I would want to study something like that.  It’s not that everybody loves poetry. Most people, in my experience, really cherish the time they don’t spend reading poetry. But some people do like it well enough, and we all know that people of that kind are out there, somewhere.

Protists are different.  Apparently, if you happen to be interested in those, you have some explaining to do.  In fact, it’s the first thing most people ask, when I tell them how I’ve been spending my days: Why are you interested in that?

It always deflates me a bit, which is fine, I would not want to be too puffy.  But would they ask me that if I were studying…tigers?

wcs_tigerresearcher

John Goodrich, Tiger Researcher (Image: A. Rybin.  Click to see source)

I’m pretty sure that guy never has to explain why he loves what he does. He catches live tigers in the wild and cuddles their babies!   That’s a solid 40 megafonzies on the Cool-O-meter. But when I mention that I’m interested — very, very interested — in “protists,” I can tell that some people do not necessarily think it is a good thing.

Part of the problem is the word “protist” itself. From a public-relations point of view, it is a mess. First, it sounds too much like a certain other English word. When the subject of protists comes up (as it always does, if I can work it into the conversation) people often mishear me, and think that I like to study and observe “protests.” Which is not so implausible…I’m sure there are “protest watchers” out there, as there are “storm chasers” and “chicken hypnotizers.”   But even when I spell the word out, people over a certain age (my generation, that is)  don’t recognize it anyway. We grew up calling these bugs either “algae” (the placid green ones that remind us of plants) or “protozoa” (the colourless ones that boogie around and try to eat each other, like miniature animals).

These days, the word “protozoa” is being phased out, in professional circles. The reason for this is perfectly sound. It means “first animals,” and protists are not animals of any kind.  The mushrooms in your fridge are more closely related to you (and your dog, and your dog’s fleas), than any of the protists in your koi pond. But although both words were coined in the 19th century, the word “protozoa” is the one that caught on and stuck. In marketing terms, it has good “brand awareness.” So, here we have a field, protozoology, that was already on the margins of the public mind, which now goes by a “new” and unfamiliar name.

And finally, once we’ve established what it is we are talking about, some people still fail to see–amazing as it sounds!–why a person might care about such a thing.  Even biologists, who should know better, tend to think of protists as a weird little sideshow in the circus of life, where the big tent is reserved for elephants, horses and (needless to say) tigers.

I’ll talk about that in my next post, I think.

First, though, since I’ve been belabouring the word “protist,” what exactly do we mean by it?  This blog is about protistology, so there will be ample time to explore that in depth, but a quick working definition might be useful. If I may adapt the excellent and succinct definition offered by Psi Wavefunction, a protist is any organism that is not a bacterium, not a fungus, not a plant, and not an animal. Which means that protistology is, effectively, the study of organisms that nobody else cares about.

Any eukaryote that is not a plant, an animal, or a fungus. – See more at: http://skepticwonder.fieldofscience.com/2008/11/what-is-protist-eukaryotic-tree-of-life.html#sthash.Yup6wXZj.dpuf
Nov 142013
 

When I was eight years old, I knew what I wanted to be when I grew up.

I wanted to be this guy:

Forty-five years later, I finally look a bit like that. It’s not the wild hair and bulging eyes (which I’ve always had): it’s the glassware. At 53, I finally have an erlenmeyer flask!  I also have a box of pipettes, and a big fat falcon tube filled with a yellow fluid that might well turn into a powerful explosive if I ever let it dry out.  I do not have a brain in a jar, but it’s only a matter of time.

In short: at a fairly late stage of life I am trying to become, in my own small way, a kind of scientist.    I have no scientific training at all.   I am a poet, who happens to have written a bit about protists and microscopy.    I’m hoping this blog will give me a place to write about the slow and sometimes awkward process of learning to think scientifically.

What I’m beginning here could be described as a “citizen science”  blog, but that term doesn’t sit well with my inner eight-year-old.   “Citizen science” is all about “making a contribution,” like those diligent bird-counters, reporting their sightings to the Cornell Lab of Ornithology; or telescope fanciers up till all hours, sifting the barely-perceptible specks from the almost-invisible flecks.   There’s nothing wrong with doing your bit for the cause, but that is not what pulled me into this.  (And really, can you picture a power-hungry “citizen scientist” cackling over a fuming flask?)

Since we do have to distinguish the self-taught amateur from the qualified pro (if only to decide who gets a turn at the electron microscope), I prefer the term “outsider science,” which hints at the kind of not-altogether-healthy obsessiveness that drives a person like me.   Of course, that epithet is, if anything, even less flattering.  While the “citizen scientist” may be, at worst, a gormless do-gooder, the “outsider scientist” appears to be (in the journalistic imagination, at least) a flat-out crank:


(Image: Reidar Hahn, via Symmetry Magazine)

But if the “outsider scientist” is a kook, he is at least a passionate one; and I’m not too proud to admit that something in that picture kind of reminds me of me.

Also, protistology is itself something of an “outsider science,” which has a long history of providing an intellectual home for dedicated autodidacts.  I will talk a bit about that in my next post, or the one after that.