Subject: Morphology in submerged culture

From: [email-masked] (James E Gannon)
Date: 4 Feb 1995 13:38:24 -0700

I have just begun working with submerged (liquid grown) cultures of 
Rhizopus.  Form the same spore prep, some times I get discrete bead like 
morphology and others I get an "uncontrolled" filamentous mass?  What 
specifically controls morphological type under submerged conditions?  
<[email-masked]).

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From: [email-masked] (mspear)
Date: 6 Feb 1995 11:15:13 -0500

> specifically controls morphological type under submerged conditions?  

In some species the speed of agitation or ammount of bubbling can have
an effect like you discribe.

    ---- Mark

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From: [email-masked] (Lejeune Robert)
Date: 1 Mar 1995 17:37:01 GMT

> an effect like you discribe.

A lot of different factors can influence the formation of pellets (the
so called *discrete beads*). In your case, if you use exactle the same
spores, same inoculation procedure, same sterilization procedure, same
everything else, then you shouldn't get any differences in morphology.
When you inoculate with spores, the pH during the germination is a good
candidate as source of your problem. e.g. A. oryzae spores agglomerate
at high pH (>5-6) and one gets pellets. If the pH is lowered, just for
the duration of the germination, then you get free mycelium.

Robert Lejeune