Field of Science

Sunday Protist - Kofoidia: Crowned by luriculae

This one will be short, as I still haven't had the chance to sit down and go on an epic research blogging adventure. Let's glance at Kofoidia, an obscure hypermastigote parabasalian.

It must think it's an Oligotrich ciliate of some sort. Poor deluded thing. Since I seem to gravitate towards obscure organisms mentioned in a single paper in all the literature available/mentioned online, there is but a sole lonely drawing of this organism:

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Parabasalid Kofoidia loriculata. Desperately in need of an SEM. Wood-eating gut endosymbiont from the Californian termite Kalotermes simplicicornis. Quick paper, anyone? (Light 1927 in Dogiel 1965 General Protozoology)

Unfortunately, I can't access the original Light 1927 paper (and ordering it may take a while...), so I'm gonna have to resort to scraps of information from Dogiel's 1965 General Protozoology, Adl et al. 2005 JEM and Kofoidia's Micro*scope page here.

So why did I randomly mention oligotrichs in the beginning? Superficially, hypermastigote parabasalia share quite a few features with ciliates. In fact, they're often described as 'slow-motion ciliates', as if they've been immersed in glycerol. Hypermastigote parabasalians, like ciliates, are covered in hundreds, sometimes even thousands, of flagella, as in this awesome Trichonympha SEM. However, unlike ciliates, they have a very different flagellar root structure, nuclear organisation (ciliates are weirder, probably), cellular organisation and the presence of 'parabasal fibres', for which the group is named. Furthermore, unlike most ciliates, Parabasalians are anaerobes, and lack conventional mitochondria, but rather possess hydrogen-generating hydrogenosomes (mentioned again here and here).

Trichonympha, a represenative hypermastigote, relative of Kofoidia. 40x DIC, mine.

While quite different and phylogenetically distant (excavates vs. alveolates), ciliates and hypermastigotes (the 'ciliated' parabasalia) so have some interesting cases of convergence. For one thing, both groups have representatives inhabiting various guts as commensals (or parasites), and in those cases, the organisms tend to be teeming with endosymbionts. Although considering how huge both of them are, it's not too suprising that even the free-living represenatives of both groups tend to attract tenants. As far as I know, next to nothing is known about parabasalian genome structure, so I can't really say much there, although obviously they lack the nuclear dimorphism the ciliates are famous for. One thing that I found particularly interesting in this example is the analogy to cirri, which are bundles of cilia found in many oxytrich ciliates, and often used for 'walking'. Kofoidia has tufts of flagella (same thing as cilia) bundled together into what Light 1927 termed 'loriculae', analogous to cirri!

These loriculae are arraged in a spiral (about 8-16 of then) and contain about thirty fairly long flagella (cirri tend to be shorter). These flagella seem bound lengthwise all the way to their tips, but fall apart upon fixation (the method of fixation isn't described). These bundles of flagella contract consecutively from left to right, as opposed to beating synchronously. (all from Dogiel 1965)

It's probably a very small thing, but somehow that jumped at me, that perhaps bundling up of flagella isn't so weird after all, as it first seems in ciliates. I wish more was known about this organism, including whether it may have any particular use for the 'loriculate' flagella, considering its termite gut commensal lifestyle. Cirri/loriculae make sense in benthic organisms (like many hypotrichs), since they obviously have a use for 'walking'. I don't know whether the term benthic is even applicable to gut endosymbionts...weird. Interestingly, the mastigont (flagellar root) systems form de novo upon cell division (micro*scope).

But probably what really jumped at me here is even more superficial -- this thing would look HAWT in SEM. Someone really needs to isolate and image Kofoidia!

It would be interesting to compare mechanisms of cytotaxis/cortical inheritance and patterning between ciliates, opalinids, parabasalians, Stephanopogon, etc., and see whether the principles are conserved (as one would expect), or if there may be different ways of regulating and inheriting cortical structure. Interestingly, all these ciliated looking things are bikonts, with unikonts exhibiting a much simpler cortical strcuture, at least in terms of flagella and basal bodies. Or so it seems at the moment. It seems that parabasalia have some basal body systems that form de novo, and some that are patterned in directed manner based on the remaining basal bodies (Adl et al. 2005 JEM). Hmmm, I've just found myself some more homework. Comparing cortical inheritance in parabasalia, opalinids and ciliates...

Dogiel 1965 turns out the be a wonderful source of tantalising organisms mentioned about ONCE in the distant past, and never looked at again. It's intriguing and annoying at the same time. Also, they actually paid attention to cell structure back then, which makes many of the old protozoology books a pleasure to look at and read. Even despite the systematic mess...

ADL, S., SIMPSON, A., FARMER, M., ANDERSEN, R., ANDERSON, O., BARTA, J., BOWSER, S., BRUGEROLLE, G., FENSOME, R., FREDERICQ, S., JAMES, T., KARPOV, S., KUGRENS, P., KRUG, J., LANE, C., LEWIS, L., LODGE, J., LYNN, D., MANN, D., MCCOURT, R., MENDOZA, L., MOESTRUP, O., MOZLEY-STANDRIDGE, S., NERAD, T., SHEARER, C., SMIRNOV, A., SPIEGEL, F., & TAYLOR, M. (2005). The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists The Journal of Eukaryotic Microbiology, 52 (5), 399-451 DOI: 10.1111/j.1550-7408.2005.00053.x

Dogiel VA (1965) General Protozoology 2nd Ed. Oxford University Press.

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