Identifying Unknown bacteria

Brian Foley brianf at
Wed Jul 27 16:08:24 EST 1994

Norman Suguitan (suguitan at wrote:
: This was shocking, and almost unbelievable.  Did I and my classmates really
: see a cocci bacteria?  The bacteria didn't look rod at all.  If they were
: a rod, what could have caused the bacteria to look like a coccus?  Need help.

	Rod-shaped bacteria can vary in length from almost spherical to 
very long.  Even within the same culture, the length of individual cells
may vary, and the length of cells in the whole culture can vary depending
on growth conditions.  i.e. well-fed, rapidly-growing cells may be different
in length from cells that are starving and starting to sporulate.

	Another possibility is that what you isolated is not what the 
professor gave you, or thought he'she gave you.  Perhaps you isolated a 
cossus contaminant, or the professor got the cultures mixed up.  Could 
you ask to see a gram-stain of a sample of the professor's culture to see 
if it looks just like yours?

*  Brian Foley               *     If we knew what we were doing   *
*  Molecular Genetics Dept.  *     it wouldn't be called research  *
*  University of Vermont     *                                     *

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