Worm Breeder's Gazette 3(2): 32

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Some Observations on Cultivation of N2 Bristol Strain on the A1 Medium

R. Ouazana, C. Bosch, N. Boemare

Figure 1

For eight months we cultivate on the A1 medium the Bristol strain 
primitively grown with E.  coli on NG agar medium.  The A1 medium is 
currently used for the Bergerac strain and its composition ( Brun 1966 
) is 
[See Figure 1]
At 18 C, in this medium, N2 shows a good adaptation.  After 60 
generations its life cycle duration was less than 3 1/2 days and the 
adult produced 298 +/- 11 progeny whose 78%, were produced in the 2 
first days of laying.  This is consistent with results obtained with 
NG agar medium ( Brenner 1974 ), but very different of those observed 
with the Bergerac strain on the A1 medium : 137 + 9 progeny per 
nematode with only 62% in the 2 first days of laying, and a 4 days 
generation time.  Therefore the differences in productivity and 
development between Bergerac and Bristol strains do not come from the 
chemical composition of the media.  They could result either from 
intrinsic differences between the 2 strains, or from differences in 
interaction with bacteria because the N2 cultivation is monoxenic and 
the Bergerac one is xenic.
Since last october, N2 is cultured on A1 medium,in aseptic 
conditions, without seeding E. coli into the plates.  The only 
transferred bacteria were those carried by worms themselves.  After 
five months of cultivation, the bacterial species associated with N2 
were identified.  We do not find E. coli, but Enterobacter agglomerans,
an Enterobacteriaceae as E. coli, but rather different of it.  The 
identification tests were carried out on 70 characters.

Figure 1