extreme halophiles

K.James bss194 at thunder
Mon Nov 11 11:22:11 EST 1996

r.england (r.england at uclan.ac.uk) wrote:

: Can anyone recommend a medium for Haloferax and Halococcus?

I worked  with Haloferax volcanii for 3 years, using DSM medium 372
to grow them. If you don't have a DSM catalogue to hand, the recipe
is (per litre):
		NaCl		200g
		MgSO4.7H2O	20g
		KCl		2g
		FeCl2.4H2O	36mg
		MnCl2.4H2O	0.36mg
		Na3-citrate	3g
		Na-glutamate	1g
		Yeast extract	5g
		Casamino acids	5g

Adjust to pH 7.2 and grow at 37C with good aeration. For plates just
add your usual amount of agar to solidify. This medium has a lot of
Mg2+ because Haloferax likes it (it's a Dead Sea isolate, after all) 
and less NaCl (it more of a moderate than a really extreme halophile).

The NCIMB catalogue has a similar medium for both strains which has
250g NaCl, 2g KCl, 7.5g casamino acids and 10g yeast extract, pH7.4 
(otherwise as above).

: Do they prefer liquid rather than agar media?

They grow pretty well on both.

: How fast/slow do they grow?

They're both quite slow growers compared to E.coli. Probably 2-5 days
to get a good, dense culture.

: Any useful tips about working with these organisms?

Keep the plates wrapped in parafilm as they are very prone to drying
and crystallising. The bugs don't mind this, but it can make picking
off colonies/ streaking out tricky.

Keith James PhD - k.james at bangor.ac.uk    PGP 2.6.2i  Key ID 469A9FA1
Biodegradation Group                         *Encrypt and Survive*  
School of Biological Sciences             Nightmare: Quake me up now!
University of Wales, Bangor, UK                                     

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