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Re: Oodinium

> Date: Tue, 30 Sep 1997 21:38:12 -0400
> From: "Maladorno, Dionigi" <DIONIGI.MALADORNO at roche_com>
> 
> Beverly Erlebacher <bae at cs_toronto.edu> wrote: <<<<Subject: Ick remedies
> (...)
> Oodinium which causes velvet disease is a dinoflagellate, technically 
> a kind of algae (Chrysophyta?), and it can indeed photosynthesize. >>>>>
> 
> Thanks for the info. I would be interested in understanding more on how
> Oodinium is "technically" a type of algae. So, algae may have flagella?

I should shoot my mouth off more often, I end up doing all this interesting
reading trying to back pedal...

When I originally studied biology, the Five Kingdom system was just
coming in, with the Protista consisting of Phylum Protozoa and algae
(other than the blue-greens) which were divided into several phyla
based mostly on which chlorophyll they had in addition to chlorophyll A,
e.g. green algae (Chlorophyta) had chlorophyll B, the others (red - 
Rhodophyta, brown - Phaeophyta, and yellow-brown - Chrysophyta) had
chlorophylls C, D, or E, not necessarily respectively.

Protozoa were divided into ciliates, flagellates, amoeboids and some others.

Nobody was really happy with this because there seemed to be a lot of 
critters that were pretty much identical to algae minus the chloroplasts
or conversely identical to protozoa except that they had chloroplasts.
There were also a lot of critters that were as much like protozoa as they
were like fungi, such as slime molds.

So I checked out the main Tree of Life home page 
(http://ag.arizona.edu:80/tree/phylogeny.html) and discovered that a
revolution in the understanding of protist phylogeny is going on, fueled
by a better understanding of subcellular structure, widespread acceptance
of the theory that mitochondria and chloroplasts and possibly other cell
structures such as cilia and flagella are remnants of endo-symbiotic
bacteria, and modern techniques for comparing DNA and protein sequences.

The green algae are more closely lumped with higher plants, and at the
same time split into a variety of new groups.  Their closer relatives 
include the red algae and a branch containing both animals and fungi.

Away from this group are a couple of dozen taxa I've never heard of
(Vampyrellids? Luffisphaera?), and the following two:

 Alveolates  (dinoflagellates, sporozoans, ciliates, etc.) 
 Stramenopiles  (brown algae, diatoms, oomycetes, chrysophytes, etc.) 

At any rate, dinoflagellates may never have been in Chrysophyta, but I
haven't been able to figure out what they used to be.  I searched the
on the keyword dinoflagellate, and found some geology/palynology sites,
since dinoflagellates are often used in dating sediments.  One page is
http://www.geo.ucalgary.ca/~macrae/palynology/dinoflagellates/dinoflagellates.html,
which contains the following info:

	Dinoflagellates are microscopic, (usually) unicellular, flagellated,
	often photosynthetic protists, commonly regarded as "algae" (Division
	Dinoflagellata). They are characterized by a transverse flagellum that
	encircles the body (often in a groove known as the cingulum) and a
	longitudinal flagellum oriented perpendicular to the transverse
	flagellum. This imparts a distinctive spiral to their swimming motion.
	Both flagella are inserted at the same point in the cell wall, by
	convention defining the ventral surface. This point is usually slightly
	depressed, and is termed the sulcus. In heterotrophic dinoflagellates
	(ones that eat other organisms), this is the point where a conical
	feeding structure, the peduncle, is projected in order to consume
	food.

	Both heterotrophic (eat other organisms) and autotrophic
	(photosynthetic) dinoflagellates are known. Some are both. They form a
	significant part of primary planktonic production in both oceans and
	lakes. Most dinoflagellates go through moderately complex life cycles
	involving several steps, both sexual and asexual, motile and
	non-motile. Some species form cysts composed of sporopollenin (an
	organic polymer), and preserve as fossils. Often the tabulation of the
	cell wall is somehow expressed in the shape and/or ornamentation of the
	cyst.

It also says that dinoflagellates are what causes "red tides", which kill
fish and kill people who eat fish and shellfish that have concentrated the
toxins from the red tide dinoflagellates they've eaten.

I hope I'm not offending people with all this tangential science stuff.
If so, please tell me, and if not, tell me too.

bae at cs_toronto.edu