Microbiology List: FW:microorganisms in fish tanks

Yersinia yersinia at cybernex.net
Wed Mar 14 17:47:03 EST 2001

Tanya writes,

< Vitek or API should have Vibrio and a variety of spirilla in their 

Actually, now that I recall, I do remember finding some Vibrio 
alginolyticus (?) on rare occasion in Vitek ID's. The spirilla, I don't 
know about, though. Is there a new card for those? Where I worked, I used 
GPI, GNI, NFC and Bacillus cards. The API strips I used were Staph, 20E 
and 20NE. Then again, I wasn't doing medical or marine bugs, either.  

<I am less sure of Oceanospirillum, but the bug seems to be fairly easy 
to ID using microscope, a couple of biochem tests and Bergey's (I've 
never done it myself though).>

Sounds like fun though. Maybe next time you catch a suspected one, you 
could try it if you have the time?

<Cyanobacteria present a REAL problem. Over the past 30-40 years, no 
consensus has been reached on the
identification of cyanobacteria.  Taxonomists of the Botanical School of 
Thought have been replaced by microbiologists, who re-classified 
blue-green algae as cyanobacteria and keep reassigning genera almost 

Is this any "worse" than what happened to the genus Pseudomonas? Geez, 
let's just take one organism here: Pseudomonas maltophilia, which became 
Xanthomonas maltophilia, then Stenotrophomonas maltophilia -- did I get 
the chronological order of the changes right here?  Then P. cepacia is 
now Burkholderia cepacia -- or has that one changed again by now? But you 
get the idea.....

<As it stands now, cyanobacteriologists do not classify down to species 
-- genus
and strain are deemed to be sufficient.  With the last representatives of
the Botanical School coming off the science scene, we will lose our 
to identify this group of microorganisms down to species.  This may answer
one part of your question.>

Forgive me if I sound naive, but didn't those scientists of the Botanical 
School publish? Is their work considered invalid?

<Identification, to genus, of cyanobacteria is done by microscopy alone.  
This is probably due to the fact that all cyanobacteria are phototrophic, 
with many of them being photoautotrophic.  Therefore, sugar fermentation 
is not a good diagnostic feature.  The trick is that depending on the 
growth conditions cyanobacteria may change morphology.  So, microscopy 
alone can also lead to mis-ID'ing.>

Well, like I said, I've never studied marine micro, and I've never worked 
with the cyanos -- doesn't matter, I find this all interesting anyway so 
I hope you don't mind my "stupid" questions. But yes, if they're 
phototrophs, sugar fermentation wouldn't be the way to go. I was just 
using that as an example (albeit now that I realize it, a bad one), since 
other microorganisms are ID'ed by those kinds of reactions. I was just 
thinking that, if you grew the cyanos on different kinds of media, 
wouldn't you get a better picture of their different morphologies? 
Meaning: if on Medium #1 it's supposed to look one way, Medium #2 a 
different way, and Medium #3 yet another way, and so on. So, if you get 
the "proper" morphology on some but not all the media, it's not the 
organism you think it is, and vice versa? But then again, I think you 
also said they usually grow very slowly, so this would take so long as to 
be impracticable....

<The 16S is of a little help, since narrow-filaments cluster with 
unicells, some halophilic unicells
cluster together, apart from freshwater unicells, etc.  In addition, 
making axenic cultures is more than a pain -- sometimes cyanos refuse to 
live without symbionts.  If I ever wanted to make someone desperate, 
and lose self-esteem, I would have offered cleaning environmental 
cultures of cyanobacteria to axenity.  (Dutch -- if you are still 
following -- do not try to do this at school!)>

Ohmygoodness -- you've got a Riboprinter?  :-D (Is that how you get the 
16S info?) I've been dying to learn that... As to the rest of this, I'm 
reduced to humbly begging you to tell me about the symbionts -- you mean 
intracellular bacteria that live inside the cyanos?

~Yersinia<-----off to dig up her college micro text and read up on 


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