Hi Mohamad,

I think you might need to get a laboratory strain for this work. You can purchase wild type laboratory (reference) strains from Euroscarf (they are based in Germany but also ship outside of Europe):

http://web.uni-frankfurt.de/fb15/mikro/euroscarf/data/ref_str.html

In my previous lab we used BY4741 background, this paper might help in deciding which strain you want to use:

http://www.sciencedirect.com/science/article/pii/S0717345814000773

Hope this helps!

Kerry

Hi Mohamad

Basically By4741/42/43 and all those which have a S288C background are really poor fermenting strains. SK1 is too a poor fermenting strain. In fact wine strains are good fermenting strains. Another aspect is the availability of a genome sequence.

As a consequence I would suggest you to have a look o the strians which genome have been sequenced by G. Liti in 2009, and which genome are available at http://www.yeastgenome.org/blast-sgd

These wine strains such as those in https://catalogue.ncyc.co.uk/sgrp/set-2/strains

I would suggest one haplid strain such as :

NCYC 3598 which is the Mat a derivative of L-1374, and us it for transformation.

The second issue is the choice : auxotrophies versus positive markers.  Surprinsingly, auxotrophies are harmfull for different phenotypes: if you have a ura3- strain and add uracile, the global growth  during fermentation will not be the same as a URA3 wild type strain. As a consequence you may have interest at using positive markers. But the choice of the strategy  depends on your objectives: one gene for heterologuois expression or introducing a whole pathway.

Last I am not sure that S. cerevisiae is the right choice for producing proteins, in comparison to Pichia.

All the best

Jean-Luc

Hello Kerry and Jean-Luc,

Thank you for your feedbacks :) I understand now that my so called off-the-table Saccharomyces cerevisiae strain is not the best for my intended work. On that note, I have a few additional questions, as explained below.

1. The EUROSCARF website has been down for quite a while so I've looked for others elsewhere as of now. Regarding the strain NCYC 3598, I have not found sufficient information (based on the link https://catalogue.ncyc.co.uk/saccharomyces-cerevisiae-3598) to make my decision on it.

Alternatively, I've looked into the following strains NCYC 1412-1415 and NCYC 3233 (https://catalogue.ncyc.co.uk/saccharomyces-cerevisiae-3233, preferable due to higher temperature and high glucose tolerance) of which more information has been made available. Please give some input as to whether they're suitable for transformation.

2. Based on Dr. Jean-Luc, I've been made to understand that knowing the genome of the strain is important for purpose of transformation. However, given that I intend to use a YEP plasmid that will not integrate into the host genome, is this information still critical? I'd appreciate it if you could shed light, or direct me to a good publication, which can help me to understand this. On the same note, is it important to use a 'haplid strain' for transformation as well?

Please forgive me if I seem so clueless, for I make no attempt to hide my lack of knowledge. Any help is much appreciated and I thank you in advance for them :)

Hi Mohamad,

The Euroscarf website appears to be working fine using the following link:

http://www.euroscarf.de/search.php?name=Order

All reference wild type strains should be suitable for transformation using standard S. cerevisiae transformation protocols.  

The information provided by Jean-Luc is still critical, as you need to ensure that your strain is compatible with the marker you wish to use when selecting for your constructs. For example, if you are using a HIS3 vector you need to ensure that the genotype of your strain is his- 

Kerry