Sunday Protist – Scary nematode-eating forams and their amazing feet of doom

Poor, poor nematodes...

In the interests of public safety, I must reiterate once again what should be so painfully apparent from the last few posts on forams: If you ever find yourself shrunk to a milimetre or less, DO NOT fuck with forams. Ever.

It's a fairly known fact around these parts that [unicellular] forams can devour [multicellular] animals. But thus far we've just had giant tree forams like Notodendrodes show us the terrifying force of microbial nature. Notodendrodes is notably bigger than its prey, so the embarrassed metazoa have an excuse there. As for giant planktonic forams – well, those eat things only slightly larger than themselves, you may say. In which case you must be almost insatiable. But, as usual, there's more: rather small, unassuming Ammonia tepida devouring nematodes, copepods and gastropods unarguably larger than itself.

Like other forams, Ammonia uses its amazing reticulopodia (lit. "net-feet") to trap and entangle prey. Then, it penetrates its prey's exoskeleton or cuticle and forcefully rips apart the insides to shreds, bringing back phagocytosed chunks towards the main cell body for digestion. This process is creepy enough to warrant its own term: skyllocytosis (Bowser 1985 J Prootozool). All that's left behind is an empty cuticle with a hole. By the way, the prey are devoured within 24 hours. And apparently forams are pretty much always hungry. Imagine being violated by masses of dynamic and powerful net-like pseudopodia and torn to pieces from the inside. Doesn't sound fun. Feels good to be big, doesn't it?

Ammonia tepida vs. nematodes. c and d show before and after shots of one such encounter. Sometimes a second foram joins for a threesome. (Dupuy et al. 2010 J Foram Res)

As for copepods...the following sentence from the paper raises some concern: "Despite vigorous attempts to escape, copepods could not free themselves from the pseudopodial mesh."(Dupuy et al. 2010 J Foram Res) Most of us have seen copepods one time or another. For the world of their scale, they're quite strong. And yet they cannot escape. Neither can snails, whose shells are all that remains after a few hours. Have I mentioned foram reticulopodia are simply amazing?

Ammonia tepida vs. copepod (a) and juvenile snails (b,c). Note how the copepod is partially eaten already towards the right. d,e - SEM view of the ventral (umbilical) end of the foram. Little bumps (pustules) are thought to potentially act as 'teeth' and used to grind tests and cuticles. Some other forams are thought to do this with diatoms as well. (Dupuy et al. 2010 J Foram Res)

You may wonder how foram pseudopodia get to be so special. They possess many unique properties, many of which have yet to be understood. One of the more striking features is the rate of microtubule growth. While microtubules of animal cells grow at about 1-15µm/min, microtubule assembly in some forams can reach a stunning 12µm per second (Bowser & Travis 2002 J Foram Res). They manage this by possessing a unique third conformation of tubulin: helical filaments (in addition to the usual protofilaments/'tubes and free dimers).

Transformation of tubulin between helical filaments and free dimers appears to require no ATP, and thus would progress quite rapidly. Furthermore, tubulin of helical filaments can transform directly to the tubules, much faster than regular polymerisation from free dimers. The idea is that tubulin is stored in helical form (crystalised, if you will), and then transported to the site of active growth, and used for a quick and efficient supply of the growing 'tubes with fresh tubulin (Welnhofer & Travis 1996 Cell Motil Cytosk). Thus, it is perhaps not overly surprising that foraminiferan tubulins are highly diverged, suggesting selective pressure for the foram-specific modifications (Habura et al. 2005 MBE). This is yet another example of bizarre alterations by a protist of typically conservative aspects of eukaryotic biology.

SEMs of foram pseudopodia entrapping prey; in this case, Artemia. (Bowser et al. 1992 J Protozool)

To have an idea of what the microtubule cytoskeleton looks like in action, here's a stolen video of plant epidermis cortical microtubules marked with AtEB1:GFP:

In vivo timelapse of cortical microtubules marked with (+)-end binding GFP growing in a tobacco leaf epidermis. Picked this one because it has a scalebar (10µm) and a timestamp (in seconds; movie is sped up, but the whole thing lasts a minute); I do happen to have my own, but finding + editing them would be a pain right now. This should give you an idea of how dynamic the cytoskeleton really is, though keep in mind it's not the best example by far. Noticed interesting recent developments in the plant cell morphogenesis/cytoskeleton story, wish I had time to keep up. (Source: Brandner et al. 2008 Plant Physiol Movie S1)

Now for the video of foram microtubules growing and fluorescing in vivo... oh wait, there is none. =(

There are no foram model organisms. Yet. As far as I know, there's no genome yet either. That should be taken care of. And someone needs to figure out how to transform/transfect (genetically) the buggers too. "Must have pretty movies of rapid microtubule growth" should look great on a grant app. Seriously, it's even shiny and glowy and stuff. Don't they like things that look like cancer/immunology research? (And this is probably why they don't let me write grants yet; not that I'm in any hurry to become a bureaucrat...)

Another foram teaser: some species (eg. Rotaliella heterocaryotica) possess two types of nuclei – germline and somatic – just like ciliates. Actually, no one has any idea how much like ciliates they are, as very little molecular work has been done. Might be another case of crazy genomic dimorphism with ridiculous epigenetic machinery, etc.

Or, just like forams themselves, it may be something else altogether.

References
BOWSER, S. (1985). Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel The Journal of Eukaryotic Microbiology, 32 (1), 9-12 DOI: 10.1111/j.1550-7408.1985.tb03005.x

Bowser, S. (2002). RETICULOPODIA: STRUCTURAL AND BEHAVIORAL BASIS FOR THE SUPRAGENERIC PLACEMENT OF GRANULORETICULOSAN PROTISTS The Journal of Foraminiferal Research, 32 (4), 440-447 DOI: 10.2113/0320440

BOWSER, S., ALEXANDER, S., STOCKTON, W., & DELACA, T. (1992). Extracellular Matrix Augments Mechanical Properties of Pseudopodia in the Carnivorous Foraminiferan Astrammina rara: Role in Prey Capture The Journal of Eukaryotic Microbiology, 39 (6), 724-732 DOI: 10.1111/j.1550-7408.1992.tb04455.x

Brandner, K., Sambade, A., Boutant, E., Didier, P., Mely, Y., Ritzenthaler, C., & Heinlein, M. (2008). Tobacco Mosaic Virus Movement Protein Interacts with Green Fluorescent Protein-Tagged Microtubule End-Binding Protein 1 PLANT PHYSIOLOGY, 147 (2), 611-623 DOI: 10.1104/pp.108.117481

Dupuy, C., Rossignol, L., Geslin, E., & Pascal, P. (2010). PREDATION OF MUDFLAT MEIO-MACROFAUNAL METAZOANS BY A CALCAREOUS FORAMINIFER, AMMONIA TEPIDA (CUSHMAN, 1926) The Journal of Foraminiferal Research, 40 (4), 305-312 DOI: 10.2113/gsjfr.40.4.305

Habura, A. (2005). Structural and Functional Implications of an Unusual Foraminiferal -Tubulin Molecular Biology and Evolution, 22 (10), 2000-2009 DOI: 10.1093/molbev/msi190

Sunday Protist - Farming forams: a case of protistan agriculture

"WTF, it's Friday already!" Friday? What Friday? You saw nothing.

My previous two Sunday Protist attempts got derailed. With the first one, noticed there was quite a bit to say about them, and decided to postpone it for later as it was a big topic (and unrelated to my current work). Then I picked something relevant to my day job, y'know, two birds one stone, etc. And somehow that led me to paleontology. A warzone in paleontology. Complete and total clusterfuck. With potential inaccuracies here and there that I now need to sort out. Whilst we wait, I'll just do something quick: a case of a foraminiferan apparently growing bacteria and then eating them in perhaps one of the most non-human farming enterprises ever! (leafcutter ants are pretty much human at that phylogenetic distance...)

Textularia blocki lives on seagrass. Many forams have interesting associations with seaweeds, ranging from internal parasitism to epiphytic attachment, usually via secretions of sulfated mucopolysaccharides, a fairly common material in the extracellular matrix. T.blocki, however, is a freely motile foram. It leaves peculiar 'grazing traces' as it crawls along the seagrass, without damaging the tissue beneath it:

Left: T.blocki with grazing traces on blade of seagrass. Right: (Langer & Gehring 1993 J Foram Res)

As made evident in the diagram, the traces consist of two parallel 'walls', consisting of pale whitish adhesive material, presumably containing mucopolysaccharides, devoid of sand grains or other contaminants. Curiously, some forams carried sand grains along, without depositing them. These secretions are formed by pseudopodia, or the 'business' part of the foram: an intricate network of reticulated feet with amazing cytoskeletal properties. When these secretions are left alone in seawater for 48h, a lush garden of bacteria sprung up specifically along the secretion traces:

Bacterial gardens along the foraminiferan secretion traces. Note the relatively clean surface of the leaf outside the secretions, supporting that it is the adhesive mucous that attracts bacterial accumulation (Langer & Gehring 1993 J Foram Res)

When released back into the medium containing the seagrass lined with traces, the forams approach the nearest trace and follow along it, suggesting they use some form of chemical sensing to determine where the secretions are and how they are oriented. The speed is then reduced, suggesting the foram is then busy grazing on their bacterial harvest.

Thus, a 'mere' single celled organism can produce organised tracks of nutritious material, wait for their bacterial crop to grow, and subsequently harvest it. We like to think we invented agriculture. The more biologically-oriented among us point out leafcutter ant fungus gardens and aphid farming. Yet, agriculture has also evolved on the unicellular scale in a small humble foraminiferan living among blades of seagrass. Humbling, isn't it?

Interestingly, a similar behaviour has been described gastropods like slugs and limpets, as their mucous also attracts bacterial growth. Convergence: when a good thing is chanced upon multiple times, it will likely be kept by several lineages independently. This applies to language and cultural evolution as well as that of biological organisms.


We tend to have a deep conviction that cells are dumb blobs of goo, incapable of any sort of behaviour besides basic phototaxis or whatever. We think cells are just simple chemical response machines – which is true. But ultimately, so are we. There is no fundamental distinction between human social dynamics and the adventures of a crawling amoeba. The difference is all in the quantity and complexity of interactions – the higher the complexity, the more random (stochastic) the system appears (and to an extent, is). While I must concede that in terms of the number of components and pathways involved, human or ant behaviours are more complex than that of an amoeba, that does not mean the proverbial amoeba 'lacks' behaviour entirely.

I've mentioned the cellular behaviour stuff before, probably too often for regular readers. Apparently, that idea needs restating though. Also, as a cell biologist, I find it quite...well, pleasing. It's nice that, ultimately, my subjects are no more or less machine-like than humans or plants. Furthermore, where I was heading with this originally, I think part of our notion of cells being 'stupid' comes from the obsession with our own cells. Animal cells are, in fact, quite simple and developmentally retarded. The cause is cell specialisation driven by multicellularity. Eg. an epithelial cell can now afford to lose the ability to hunt around for prey, it no longer needs to coordinate movement in any sophisticated manner, the life cycle can be simplified to terminal differentiation.

Curiously, a similar problem plagues modern science and engineering: overspecialisation means that one must no longer have the same level of foundational education to survive, and thus we end up arguably knowing more about less, or perhaps knowing the same about less. I can suck at math or chemistry and get away with it. In the old days, people had to actually have a broader base just to function. Conversely, there was also less information floating around. Which is more efficient? Just as multicellularity vs. unicellularity, each system has its merits and drawbacks. So it's hard to tell.

A while back I found a paper on cellular complexity in multicellular vs. unicellular organisms that needs to be discussed in greater detail eventually...


---Random Link---
ChrisM over at the wonderful Echinoblog (about the cooler deuterostomes; ok, hemichordates and ascidians are cool too) wrote about sperm-eating ciliates infesting starfish.

Lots of things like sperm. For example, Monocystis is a gregarine with a penchant for earthworm sperm – infection rates are so high that if you slice up a worm from your backyard and smear the contents of its seminal vesicles on a slide, the chances are pretty good that you'll find some. And by 'some', I mean, LOTS. So if you're ever in the mood for some apicomplexans, all you need is an earthworm, a blade and a scope. There are parasites in pretty much anything and everything, so if you go around examining various animals, you may well find loads of cool protistan denizens in them. Many of which could be undescribed and, perhaps, new to science.

Reference
Langer, M., & Gehring, C. (1993). Bacteria farming; a possible feeding strategy of some smaller motile Foraminifera The Journal of Foraminiferal Research, 23 (1), 40-46 DOI: 10.2113/gsjfr.23.1.40

Carnivorous trees of the sea: Notodendrodes not as harmless as it looks

Remember Notodendrodes and the spicule tree? Don't they look so much like harmless trees sitting around sunbathing like their plant counterparts? Not all tree forams are harmless. The microscopic marine world is full of surprises, like trees waving around their long sticky network 'feet' to trap and devour any traveler that happens by. Here's some wonderful shots of Notodendrodes caught in the act:

The top left image shows a clump of Artemia caught by Notodendrodes, a big carnivorous tree foram. Note how the reticulopodia (pseudopodial networks) stretch between the branches like spiderwebs. Top right: SEM of the reticulopodial mesh of another species of Notodendrodes. Bottom: The tree foram in its natural setting, with a copepod attached (arrow). (Suhr et al. 2008 Mar Ecol Prog Ser)

There some nice foram videos on this YouTube page, including shots of reticulopodia and a fairly large foram moving about in situ. This movie by a Japanese researcher includes clips of Artemia being captured starting at 0:50.

Many forams are voracious predators, devouring anything from fellow protists to crustaceans and echinoderm and mollusc larvae. The following is Astrammina rara's rather impressive menu; all but two species were happily consumed:

However, not all forams are carnivorous. Some are mediocre at best at capturing prey, and some, like Crithionina, are quite bad. This suggests a range of feeding habits from detritovory to carnovory to omnivory. Note how Gromia (not a foram, despite looking vaguely similar; placement somewhat uncertain, though most likely either close to forams or a cercozoan) fails to capture any prey. Also, dead specimens failed to catch prey, indicating the capture is intentional and requires a fully functioning cell, and not an accidental adhesion to something sticky. In fact, there is evidence for specific targetting of certain prey, which wouldn't be much of a stretch as many forams are quite picky in choosing their test material.

I think this has some interesting – perhaps borderline philosophical – implications. Towards the end of the ciliate kleptoplasty post I mentioned how the traditional ecological terms often fail to describe the majority of life, which happens to be microscopic and play by some different rules. There's a greater problem in the approach of traditional ecology towards microbial life, however, and it even surfaced in a random chat with some ecology grad students. Namely, the treatment of all things microbial as the "bottom of the food web", ie. prey species created by evolution to feed cute fluffy animals. They have a similar attitude to plants as well: 'producers'. Fungi are 'decomposers'.

Probably to people tracking bird migration out in the field, such crude terms do just fine, and we all must make crude approximations somewhere (or drown in details). However, as in any simplification, there's always a danger of skimming over interesting outliers. I disagree with the blanket treatment of protists (and bacteria, and anything else) as the "bottom of the food web" for two reasons:

1. There are plenty of intricate interactions resulting in elaborate food webs (and, more generally, 'interaction webs'); a plethora of fascinating relationships is lost when one blurs them all into the 'prey for animals' category.

2. Feeding by animals forms but a very tiny part of the overall diversity of microbe-animal interactions. An ecological framework must account for symbionts (mutualists, parasites and commensals) along with predation. Toxoplasma, arguably the most successful parasite of vertebrates ever, is a wonderful example of 'lower trophic levels' leeching 'up' the food web and running the show. You can't really draw an arrow from a cat or human to the modest apicomplexan, as it doesn't really consume its slaves. But you can't really not draw that arrow. It's complicated.

(In fact, if organisms besides humans had Facebook, most of their relationship statuses would be set to "It's complicated". Groan all you want... =P)

Lastly, our forams mentioned above also have ecological consequences on the megafauna in their environments. Astrammina rara is benthic, meaning it lives on the ocean floor (or, technically, any substrate). Suhr et al (2008) mention past studies indicating lower-than-usual densities of marine fauna in particular areas; these areas seem to match up with Astrammina's distribution. Presumably, the effects of predation on small fauna and larvae can be seen on the larger scale.

Furthermore, the carnivorous forams seem to affect the survival strategies of the fauna around them (in hindsight, unsurprisingly): some echinoids have brood protection and settling strategies that may well have evolved in response to the lowly single celled protists they rightly fear. The authors suggest that the failure of Astrammina to capture larvae of the echinoid Acodontaster may be a result of the latter evolving a specific chemical defense against it.

The 'scum' from the bottom of the foodweb can come up to bite some 'higher' organisms in the ass – whodathunk?

Reference
Suhr, S., Alexander, S., Gooday, A., Pond, D., & Bowser, S. (2008). Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory Marine Ecology Progress Series, 371, 155-164 DOI: 10.3354/meps07693

Sunday Protist - Giant tree of spicules: Spiculidendron

Christopher Taylor over at Catalogue of Organisms has a nice post on agglutinated Saccamminid foraminifera, and very recently wrote on the taxonomy and morphology of Pelosina, Pilulina and Technitella, wherein he brought up a fascinating paper on one hell of a bizarre foram: the 'spicule tree', initally mistaken for a gorgonian (sea fan). I'm going to leech off his find as he didn't specifically mention this tree foram in his post. Also, he mentioned Komokians before I did. Meanie. In all seriousness, go read his posts. For the phylogenetically inclined protistologists, the Komokian post is good food for thought.

I'm going to slack off a bit this time. For an overview of the huge clade of awesome that is Foraminifera, see my earlier post here; for another tree foram, see Notodendrodes here.

Foraminiferans are amazing creatures: some of them can be best described as giant cannibalistic carnivorous wads of sticky reticulated pseudopodia, capable of snaring and devouring small metazoans and Volvox colonies. They have the fastest microtubule growth rates in the eukaryotic kingdom - a whole two orders of magnitude greater than those of animals at a stunning 12µm/s! (animal cells grow microtubules at around 1-15µm/min.) (Bowser & Travis 2002 J Foram Res) Their pseudopodia are themselves capable of shearing flesh in a process so unique it deserved its own name: 'skyllocytosis' (Bowser 1985 J Protozool). Do not screw around with forams. They are scary.

Most of them also have shells, but that's a story for some other day. Well, many stories, for many days. Forams are a huge and diverse group.

The following specimen belongs to Astrorhizidae, a group of agglutinating forams - meaning their tests are composed of material from the environment, often very selectively picked. As implied by its name, the spicule tree, or Spiculidendron, composes its test entirely out of sponge spicules. Furthermore, this contraption reaches a stunning 60mm (6cm) in height, as a single-celled organism!

Plant, animal or protist? A foram tree to shame all foram trees. A giant spicule-covered monster from the Caribbean tropics. (Rützler & Richardson 1996 Biologie)

The paper mentions difficulties in determining whether the spicule tree bears a single nucleus or is coenocytic. Presumably, if it was that hard to find (though they had few specimens to work with), it may well be uninucleate like Notodendrodes. This would be quite cool as 6cm is one hell of a giant cell to be supported by a single nucleus. The cytoplasm also contains symbiotic dinoflagellates, making this tree foram even more like an actual tree.

Note that this strange monster of a foram was only described in 1996. The age of exploration is far from over.

References
Rützler, K., & Richardson, S. (1996). The Caribbean spicule tree: a sponge-imitating foraminifer (Astrorhizidae) Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 66 (Suppl.), 143-151

Bowser, S. (2002). RETICULOPODIA: STRUCTURAL AND BEHAVIORAL BASIS FOR THE SUPRAGENERIC PLACEMENT OF GRANULORETICULOSAN PROTISTS The Journal of Foraminiferal Research, 32 (4), 440-447 DOI: 10.2113/0320440

BOWSER, S. (1985). Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel The Journal of Eukaryotic Microbiology, 32 (1), 9-12 DOI: 10.1111/j.1550-7408.1985.tb03005.x

Sunday Protist -- Notodendrodes: giant tree forams

Foraminifera are wonderful organisms. For a glimpse of their phylogeny, see this diagram, but keep in mind that the majority of forams are actually allogromiids, forams which build their walls of protein as opposed to scavenged material or depositing mineral substances. From the allogromiids there have been several independent origins of non-proteinaceous forams, many building their tests out of sand grains, remnants of prey or their own waste. Test-building is a complicated and highly regulated process (many forams actually select sand grains with the right properties for building their tests!), a topic I should get around to eventually (not with those dark menacing storm clouds rapidly approaching from the horizon signalling the inevitable Armageddon finals). Thus, I figured that for this superficial protist appreciation post one can't go wrong with Notodendrodes, a genus of forams that look like trees!

Notodendrodes, like their sphaerical relative Rhabdammina, build their tests out of sand grains, especially quartz. Unlike Rhabdammina, they also have extensive "root" and "arborescent" structures sticking out of the sphaerical shell and into the sand and up in the air, respectively.

Notodendrodes antarctikos from the deep sea, arborescent structure. Image from Bowser lab, shamelessly stolen from certain course slides.

One must also note that forams extend far beyond their tests: they are surrounded by a complex network of extruded strands of cytoplasm forming the reticulopodia. These networks can be used to capture prey, absorb nutrients and, in some species, transport algal symbionts far outside the shell to harvest light energy. Notodendrodes lives too deep for housing photosynthetic symbionts; it is said to use its root pseudopodia for absorbing nutrients from the sediment and the arborescent network for sifting through the algal rain falling from the surface (Bowser Lab webpage on Notodendrodes ).

Notodendrodes hyalinosphaira. Scalebars: A,B - 2mm; C - 1cm; D - 5mm (DeLaca et al. 2002 J Foram Res)

These cells are quite sophisticated and should make great companions for cell biology research. The reticulopodia are able to move things along them (seems to be widespread feature among Rhizarians), and before you get the idea that these giant cells are docile and harmless, some forams can prey on small animals like copepods. There are some truly frightening micrographs in OR Anderson's Biology of Foraminifera.

Notodendrodes is apparently uninucleate. Wonder what ploidy levels would be needed to sustain such a monster-sized cell...

Anyway, this post fails to do justice to these organisms, but this week is simply awful for me, so I must leave it at that. My whole life is due this week. Also, I have three weeks left to finish wrapping up my current research project, and I'm having great difficulty focusing on it with all the course-related crap on top of it. Expect negligible blogging efforts in the next few weeks...

By the way, Mystery Micrograph #20 feels neglected. Do you guys need a few more micrographs for help?

Meanwhile, some random foram stuff to look at:

Illustrated Glossary of Terms Used in Foraminiferal Research

Pretty SEMs: Forams as Bioindicators: Key tropical and Carribean taxa

Foram gallery at Microscopy UK

Bowser Lab page on forams

References

Bowser, S. (1995). Larger agglutinated foraminifera of McMurdo Sound, Antarctica: Are Astrammina rara and Notodendrodes antarctikos allogromiids incognito? Marine Micropaleontology, 26 (1-4), 75-88 DOI: 10.1016/0377-8398(95)00024-0

DeLaca, T. et al. (2002). NOTODENDRODES HYALINOSPHAIRA (SP. NOV.): STRUCTURE AND AUTECOLOGY OF AN ALLOGROMIID-LIKE AGGLUTINATED FORAMINIFER The Journal of Foraminiferal Research, 32 (2), 177-187 DOI: 10.2113/0320177

ToE Expansion pack: Foraminifera!

After getting over my little moment of rage there, I decided to go ahead and redo the forams while I could still vaguely remember the phylogeny, sort of. So here comes the Tree of Eukaryotes Expansion Pack: Forams!

Edit 04.04.10: Note that the majority of forams are actually the paraphyletic allogromiids, which, I am told, are to forams as protists are to eukaryotes.

I hope somebody is happy now, after nagging me about the freaking forams for the past two weeks! I know they deserve more space, and I did them an awful injustice by shrinking the entire group to just 'Forams'. Since I still haven't figured out the space problem (should I just shrink everything to 8pt font and add another 100 taxa or so?), I decided to make a special little expansion pack by crudely offending the Radiolaria and Cercozoa. I'd add more images, but it's almost 3am so...later. Also, this tree is liable to be very wrong, so perhaps I don't really need to polish it up just yet. Some groups seemed a bit confusing...

Apparently it's unknown whether Komokians are forams or not, as no living specimen have been recovered (damn suckers insist on living at the very bottom of the ocean), and it's uncertain whether they even have reticulopodia, although presumably they should. Komokians are so awesome...!

No time to finish the Sunday Protist to'night', but I totally just spoiled the surprise. Yes, it'll be a foram. And yes, it will be weird.


Flakowski, J. (2005). ACTIN PHYLOGENY OF FORAMINIFERA The Journal of Foraminiferal Research, 35 (2), 93-102 DOI: 10.2113/35.2.93

HABURA, A., GOLDSTEIN, S., PARFREY, L., & BOWSER, S. (2006). Phylogeny and Ultrastructure of Miliammina fusca: Evidence for Secondary Loss of Calcification in a Miliolid Foraminifer The Journal of Eukaryotic Microbiology, 53 (3), 204-210 DOI: 10.1111/j.1550-7408.2006.00096.x

LONGET, D., & PAWLOWSKI, J. (2007). Higher-level phylogeny of Foraminifera inferred from the RNA polymerase II (RPB1) gene European Journal of Protistology, 43 (3), 171-177 DOI: 10.1016/j.ejop.2007.01.003

Pawlowski, J. (2003). The evolution of early Foraminifera Proceedings of the National Academy of Sciences, 100 (20), 11494-11498 DOI: 10.1073/pnas.2035132100

Sunday Protist - Assorted forams

I kind of got distracted while writing up a long post about ***** (you can wait until it actually comes out, probably next week! =P), so I'll do another short one for today. Also, a giant hint for the Mystery Micrograph, since y'all are taking so long. (another hint - I first heard of it in Ball GH 1968 "Organisms living on and in protozoa", in Research in Protozoology (ed. TT Chen); ok, I'll stop bragging about my fledgling old protistology book collection- hey, have I mentioned AC Stokes 1888? Got that for 2$ at the library discard sale... /derail)

Here we go, some random foraminifera (basic intro here):

Inspiration for a sci-fi novel spaceship? Tubulogenerina; source here, along with more forams among other things

I may do a more thorough write-up on forams later, but I don't have AO Roger's books here (and the library is still closed), and it's practically impossible to write anything intelligent about foram biology without them. Most of the literature on forams, which is quite large by protistological standards, tends to be from a paleontological/geological perspective. It's not so easy to find information on their biology, especially on the cellular level (people seem to prefer treating them with some gas or metal or confiscating a nutrient, and then measuring population-level responses; perhaps because that way you can avoid dealing with the microscopic level of things)

So a few more pictures instead:

Fossil Amphycoryna scalaris, Uni Southampton gallery of foram SEMs

Calcarina hispida; foraminifera.eu site contains really a really awesome gallery, the best I've seen so far!

Some can get quite large (bar = 1mm) like this Psammatodendron arborescens from Foraminifera.eu

Nature's concrete? Psammosphaera fusca, again from Foraminifera.eu

A really nice pic of a foram shell (~1mm wide) from Snail's Tales (which you should all visit, btw. At least to remind ourselves from time to time that slugs and snails actually exist o_O)

Before we forget that these things were once alive too. The 'needles' are thin pseudopodia (filopodia) extending from the organism in its shell. Some keep symbiotic algae with them; in some species, during the day, the algae are transported to the tips of the filopodia where they can photosynthesise, and drawn back in for the night (aww!). And some have even bothered to make little 'windows' in their shells to allow light to reach inside. Here we have Globigerina, from here.

Lastly, I found us the coolest apple pie ever made in the history of mankind:

Forams made out of marzipan (and there is not a single word of that I don't like!) (Hannes Grobe at Wikimedia Commons)

PS: You know how searching for information on one thing can lead you to come across interesting tidbits on something else? I randomly came across this paper:

JO Corliss 1974 Taxon Time for Evolutionary Biologists to Take More Interest in Protozoan Phylogenetics?

"Darwin, as someone has recently commented (H. Sandon, unpublished MS), wrote "On the Origin of Species" without any mention of protozoa, and evolutionists ever since have followed his example. Scarcely a decade ago, Simpson (1961) matter-of-factly concluded that for the protists "evolutionary classification is not yet practicable. . ." and thus "they do not concern us in this book," his volume on principles of animal taxonomy and classification." (p497)

Things don't change very quickly in academia, do they? (even in the era of a relatively well-sorted protist phylogeny!) Funny how what Darwin wrote, and failed to write, has such an impact on evolutionary biology even today, [almost exactly] 150 years later. Not that I have any issues with Darwin, but should we really base much of our research planning on 19th century work?