cyanelles

charles francis delwiche cdelwich at nickel.ucs.indiana.edu
Tue Mar 15 12:26:31 EST 1994


In <CMp4JK.BJB at suncad.camosun.bc.ca> uk576 at freenet.Victoria.BC.CA (David E. Hayman) writes:


>Does anyone no anything about cyanelles which are a type of 
>or different species of cyano bacteria that found in 
>other plants.  They act like chloroplasts but can function
>normally on their own. I believe that they have lost their cell
>walls or have reduced cell walls
>Gary (David E. Hayman)

>uk576 at freenet.victoria.bc.ca


Although plastids are themselves derived from cyanobacteria, cyanelles
are plastids, not cyanobacteria.  Like plastids, cyanelles have a
greatly reduced genome, and they are *not* capable of living
independently of their host cell.  Some cyanelles have residual cell
walls, others do not.  Whether cyanelles reflect an independent
endosymbiotic event is subject to some debate, but my best bet is that
they do *not* represent an independent endosymbiotic event, and they
just look a little funny because they are a very deep phylogenetic
branch, and have retained different ancestral characters than other
plastids.

For a good summary of information on organisms with cyanelles, see L.
Kies and B.P. Kremer (1990) "Phylum Glaucocystophyta" IN L. Margulis,
J.O. Corliss, M. Melkonian, and D.J.  Chapman, eds.  _Handbook of
Protoctista_, Jones and Bartlett, Boston.  By the way, if you aren't
familar with the Handbook of Protoctista, it is packed with
information, but don't take the taxonomy presented in it too
seriously.  A lot of exciting work has been done since 1990 on the
genetics of one taxon with cyanelles, _Cyanophora paradoxa_.  See, for
example, the work done by Don Bryant.

Charles Delwiche
____________
-- 
Charles F. Delwiche		Tel: (812) 855-2549
Dept. Biology, JH 142
Indiana University
Bloomington, IN 47405     



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