Sunday Protist - Lagynion: bottled algae

Quick one today as I should really be writing a chapter, as well as the post on plastid thiefs some of you wanted. And haptophytes. Have I mentioned my ADD tendencies?

While I find ochrophytes (large group including diatoms and kelps) a bit too phycological for my tastes, some of them are actually really cool, especially Chrysophytes - the 'golden algae'. Chrysos include things like scaly flagellates (Paraphysomonas) and Dinobryon which makes colonies that look like trees of stacked wine glasses. A while ago we had bottled ciliates, and this time the Chrysophytes offer us a few bottled algae, especially the flask-shaped Lagynion.

A happy(?) clump of photosynthetic flasks, of Lagynion. Source: Micro*scope.

The lorica consists of organic material. The progeny following division are released as little zoospores bearing the ridiculously complicated flagella characteristic of ochrophytes (one of them too short to be easily visible). Then the zoospores settle down, become amoeboid and grow themselves a new flask. As far as I could gather, that's pretty much all there is to say about Lagynion at the moment. But it still looks pretty cool!

1. Side view. Arrowheads indicated a rib structure surrounding the 'flask'. 2 and 3: top views of three Lagynion cells showing optical sections through the base and the neck regions, respectively. 4. TEM of 'flask'. Note the plastids (C) and the nucleus (N). V - peripheral vesicles. In short, plastids in a bottle. (O'Kelly & Wujek 2001 Eur J Protistol)

In fact, there's a whole family of bottled, and often amoeboid, algae called Stylococcaceae (eg. see Nicholls 1987 J Phycol), but they are so obscure it's painful to find much literature on them, or even decent pictures. Especially since by the time they get digitised, a lot of the old images become completely illegible. But here's another member of the family bearing slightly different glassware, Chrysopyxis:

Source: Micro*scope

Now to do real work and then write up some of the really exciting stuff I came across lately. And crush my writer's block with something sharp and heavy. Really annoying when you can't write anything because, well, you can't write anything. Wish brains came with instruction manuals...

References
Nicholls, K. (1987). CHRYSOAMPHIPYXIS GEN. NOVA A NEW GENUS IN THE STYLOCOCCACEAE (CHRYSOPHYCEAE) Journal of Phycology, 23 (3), 499-501 DOI: 10.1111/j.1529-8817.1987.tb02537.x

O'Kelly, C., & Wujek, D. (2001). Cell structure and asexual reproduction in Lagynion delicatulum (Stylococcaceae, Chrysophyceae) European Journal of Phycology, 36 (1), 51-59 DOI: 10.1080/09670260110001735198

PS: Hardly relevant but kind of newsworthy: First Phaeophyte genome sequenced! (Cock et al. 2010 Nature) Until now, the only complete Stramenopile(=Heterokont) genomes were a couple diatoms and oomycetes. Ok, there's still many more to go but Phaeophytes can be interesting in terms of studying the evolution of multicellularity. Also, the ochrophyte clade is a phylogenetic mess; not that single whole genome data means much but could perhaps helps calm the harsh seas somewhat.

MM#11 Answer: Rhizochromulina: algal amoeba

Remember this from a looooooong time ago?

Rhizochromulina. Mischievously looks like a chlorarachniophyte... [source]

As a warning, about the only marginally comprehensive ochrophyte phylogeny I found was in TC-S & Chao, J Mol Evol. It looks like this, and makes me want to cry:

[no comment needed] (TC-S & Chao 2006 J Mol Evol)

In case those names look simply alien to you, you're not alone. In fact, I wouldn't be surprised if they'd stump some phycologists. Ochrophyte phycologists. This, my friends, is where we enter the bottomless pit of chaos that is Cavalier-Smith Taxonomy. It's a special kind of taxonomy, so I capitalised it.

So Rhizochromulina belongs to Actinochrysia in Alophycidae in Hypogyristea in Marista in Ochrophyta. I wonder if the latter is the only one of those which human beings actually use. Eikrem et al. (2004 Phycologia) put Rhizochromulina and co. in Dictyophyceae, which seems to be the taxon used by the world outside Tom's head. Seems like Dictyophyceae = Actinochrysia exactly; save for a milirank difference. That way, Tom gets to take an old, well-accepted group and liven things up with a fresh name. And get his own attached to it. Damn good deal he's got there...

Anyway back to algal amoebae...Rhizochromulina's fellow Dictyophyceans include the silicoflagellate Dictyocha, a 'heliozoan' Ciliophrys and a loricate flagellate Apedinella[photo]. And Pteridomonas, which appears to be a wannabe Choanoflagellate. Such a small group, such morphological diversity. Although, I don't know whether I can say that yet...

Initially I wanted to do a big overview of Stramenopile (fine, "Heterokont", happy?) amoebae, and take a look at their phylogenetic distribution to try to guess how easy it can be for cells to switch between amoeboid and flagellate forms through their evolution, and whether the easier direction would be from flagellate to amoeba or vice versa. This has some implications in cellular evolution, as well as the overall eukaryotic tree and its much-contested root. TC-S 2009 JEM(free access) argued (sigh.) for an important aspect of the unikont-bikont split being cytoskeletally amoeboid vs. flagellate cell morphologies (see my Naegleria post for further info), as well as evoking lateral transfer of myosin II (a motor protein [mostly] unique to unikonts, that is, opisthokonts like us and amoebozoans(Richards & TC-S 2005 Nature)) to Heteroloboseans (bikonts), enabling their complete transformations between amoebae and flagellates. Ok, take home message: I wanted to have a closer look at the EPIC MESS that is eukaryotic cellular evolution.

I wanted to fix this mess with a group that's well-known, relatively well-studied (or so I thought), with its phylogeny all sorted out. Ooops. Ochrophytes, despite being home for kelps and diatoms and such, do not qualify, apparently -- their phylogeny is a mess, many of their groups completely understudied, and...yeah, my little amoeba exercise kind of failed miserably as I fell deeper and deeper into confusion.

Furthermore, I need to figure out how the various ways of being amoeboid, flagellate, and amoeboflagellate really differ from each other, and how best to classify them to analyse the situation properly. At best, this will take A LOT of reading. But this is overly optimistic -- it assumes that there exists proper reading material in the first place! This story might actually have to wait until we learn more protistan cell biology.

Now that Rhizaria also seems to be among Chromalveolates, things get even weirder. Rhizaria is full of amoebae, full of flagellates, and everything in-between. Although as far as I know, most Rhizarians have at least some flagellate stage, even the Chlorarachniophytes. Rhizaria is also a huge mess, and even more obscure than the Ochrophytes. There's just SO MUCH untapped diversity and opportunity for biologists of all sorts to truly study eukaryotic evolution as it ought to be studied...which is why I get so livid over how cell biology is generally taught -- from this dull, lifeless zoocentric "This gene is linked to cancer" perspective where they seem to think that memorising signal transduction pathways is a worthwhile activity.

No, learning about just how many ways a cell can be is far more worthwhile and educational. It's much more informative to learn biology from a perspective of diversity. I'd argue this is even true for the biomed-oriented spawn of Satan researchers: any kind of biology without comparative work is blind and shortsighted, and to understand how a particular cell type responds in a particular form of cancer, one must first understand how eukaryotic cells work, period. And it's shameful and stupid to foresake the rest of the Eukaryotic Tree when any help is so desperately needed in comprehending the mess that >3 billion years of evolution have left us in.

Enough of my ranting (taking a cell physiol course at the moment, feeling rather sore about the obsession with macrophages and cancer cell signalling)... have another Ochrophyte amoeba:

Chrysamoeba. (Hibberd 1971 Eur J Phycol)

Some Rhizarians look vaguely like that too. Hmmm.

Yeah, I really hit a brick wall with this post. Don't really have the time to sort out messy fields at the moment, as much fun as it is. Anyway, right, midterm...

References:
CAVALIER-SMITH, T. (2009). Megaphylogeny, Cell Body Plans, Adaptive Zones: Causes and Timing of Eukaryote Basal Radiations Journal of Eukaryotic Microbiology, 56 (1), 26-33 DOI: 10.1111/j.1550-7408.2008.00373.x

Cavalier-Smith, T., & Chao, E. (2006). Phylogeny and Megasystematics of Phagotrophic Heterokonts (Kingdom Chromista) Journal of Molecular Evolution, 62 (4), 388-420 DOI: 10.1007/s00239-004-0353-8

Eikrem, W, Romari, K, Latasa, M, Le Gall, F, & et al (2004). Florenciella parvula gen. et sp. nov.(Dictyochophyceae, Heterokontophyta), a small flagellate isolated from the English Channel Phycologia, 43 (6), 658-668

Hibberd, D. (1971). Observations on the cytology and ultrastructure of Chrysamoeba radians Klebs (Chrysophyceae) European Journal of Phycology, 6 (2), 207-223 DOI: 10.1080/00071617100650231

Sunday Protist - Bicosoecids

So this past Mystery Micrograph has two 'half'-winners: 1. My friend's PI who can randomly pick out obscure flagellates by wandering around his lab - being unaware of this blog's (and my own) existence, we can say that's a half-win. 2. Jan, after I gave it away in the two very massive hints, so that also only counts for half. Jan is the first non-faculty member to get one of these, so congrats!

The MM answer was:
Bicosoeca

(Tong et al. 1997 Polar Biol.; Bicosoeca)

Bicosoecids are non-photosynthetic stramenopiles (see the first diagram in the Chromalveolata post); this one specifically builds itself a lorica, from which it filters the current with it's feathery anterior flagellum. (similar to choanoflagellates in some ways) They also look a bit similar to Chrysophyte Dinobryon (I spelled it right this time! =P), except that Bicosoeca lacks visible plastids. Some Bicosoecids like Pseudobodo and Cafeteria don't bother making loricas, and just anchor themselves to the substrate with one of the flagella. According to Cafeteria's Encyclopedia of Life webpage:

"As to the source of this name; it was prompted by a pink neon sign affixed to the wall of a hostelry in Roenbjerg (Denmark)which was illuminated just as the authors'were about to give up on finding a good name for one of the most significant consumers in the world."

Sometimes taxonomy can be quite humourous!

Despite being fairly common, these little critters are quite understudied, and very little is known about them beyond their basic morphology. Notice a common theme arising among most protist posts? Do something! We don't need THAT many people crowded on the N-terminus of some random mouse 'oncogene' (whatever that means), and there's space here!

I'll try to make next week's Mystery Micrograph a bit easier!