Need recipe for low pH YPD plates

[Francisco G da Nobrega ib - bio 7588]

On 20 Oct 1995, Solange S de Camargo wrote:

>=20
> Dear Louis,=20
>=20
> =09I think you should make the agar solution at 3.0 % (2-fold=20
> concentrated) alone.  Autoclave it and then mix to the YP medium,=20
> also previously autoclaved and previously prepared at the=20
> desired pH. Then, you should homogeneize it and add dextrose.  =20
> =09I guess your problem is because the low pH and the high=20
> temperature are hydrolizing the proteins of the agar.=20
> =09Good luck!
>=20
> =09Solange
>=20
>=20
Hi Solange!

You are right about the low pH and high temperature will hydrolise the=20
agar. So autoclave agar in separate and at about 45-50 oC add the low pH=20
media concentrate and plate. But you are not hydrolising the "proteins"of=
=20
the agar ! Agar is a polysaccharide.

F.G. Nobrega
Universidade de S=E3o Paulo
Biologia - IBUSP
C.P.  11461
05422-970   S=E3o Paulo  -  SP  - Brasil
Voice: (011) 818-7588   Fax: (011) 818-7553    E-mail:  fgdnobre at usp.br
=09=09=09