Yeast biologists - worried about contaminating lab strains?

Do any of you other yeast biologists/geneticists worry about contaminating your lab with wild/brewing strains of yeast. I know our lab strains generally have very large cell size, etc., but I don't want to mess up any experiments by bringing brewer's yeast into the lab.

I guess proper technique trumps all, yeast can come from anywhere!

I don't bring my brewing yeast into my TC lab.

j1laskey said:

I don't bring my brewing yeast into my TC lab.

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Oh absolutely, contaminating mammalian cell lines would be a no, no. We even have a hard time convincing the flow cytometry core to run our live yeast surface-display samples.

I work on directed evolution in yeast, no mammalian cells in our lab. The PI is cool with it, another PI down the hall has a brewing yeast bank. My PI seems to agree, it's up to the individual researchers to maintain pure strains.

You have nothing to worry about

I don't think bacteriologists worry about exogenous E.coli contaminating their labs.

Just don't create your starter on your work stir plate and you should be fine! My E.coli from my work that contains a plasmid with beta-amylase hasn't contaminated my brewing yet...but that might just increase my efficiency

BeerDoctor5 said:

You have nothing to worry about

I don't think bacteriologists worry about exogenous E.coli contaminating their labs.

Just don't create your starter on your work stir plate and you should be fine! My E.coli from my work that contains a plasmid with beta-amylase hasn't contaminated my brewing yet...but that might just increase my efficiency

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Heh Heh, that was my major concern, using the lab shaking incubators. Talked to the bossman, incubators are not sterile environments and it's up to us as researchers to keep things out of their samples!

ScoRas said:

We even have a hard time convincing the flow cytometry core to run our live yeast surface-display samples.

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A little off topic -

My brewing partner (product engineer) is in process of building a flow cytometer from high end microscopy parts that his company scrapped. I've been "assigned" the job of figuring out yeast assays. Right now I'm trying to figure out ways to differentiate (fingerprint) different yeast strains/identify presence of contaminants in a sample, but I'm also interested in any suggestions around vitality or viability studies.

It would be good to discuss ideas with biologists who also brew beer. Would one of you folks be up for a little correspondence?

brewguyver said:

A little off topic -

My brewing partner (product engineer) is in process of building a flow cytometer from high end microscopy parts that his company scrapped. I've been "assigned" the job of figuring out yeast assays. Right now I'm trying to figure out ways to differentiate (fingerprint) different yeast strains/identify presence of contaminants in a sample, but I'm also interested in any suggestions around vitality or viability studies.

It would be good to discuss ideas with biologists who also brew beer. Would one of you folks be up for a little correspondence?

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You guys are actually building a flow cytometer for analyzing brewing yeast strains? If so, you guys have definitely won the award for "going overboard" on this homebrewing things!!...and I mean that in the best possible way.

I'd be interested to hear what you are up to...you could say I'm a biologist who brews beer!

I was allowed to do yeast starters in the shaker incubator at school with no worry about contaminating the bacterial cells we kept on hand. It was up to the profs and students to keep contamination out of their samples and work. Unless you're working in a clean room of sorts with HEPA and air locks I don't see how you bringing it in would cause anyone problems. Specific pieces of equipment that are only really used for one type of cell could pose a problem I guess but no more than airborne contamination if you ask me.

There are low levels of bacteria, molds and fungi in the air, surfaces in the environment and certainly on your body. I presume, if you use proper lab technique you are not getting a lot of contamination of your cultures. Furthermore, most yeast molecular biologists and geneticists use E.coli extensively in their laboratories and, if not their own, certainly the labs around them do. Hence the need for sterile technique. If your stocks aren't constantly becoming contaminated with E coli, which are easy to see because they grow quickly and take over a culture, they are unlikely to be getting cross contaminated with other yeast. In my experience, it is relatively uncommon to get different laboratory strains cross contaminated except by making the mistake of mixing them. We work regularly with hundreds of strains and multiple species of yeast and don't have a problem. Just be careful.

The other issue brought up here is contamination of mammalian cells with yeast. Saccharomyces cerevisiae doesnt grow well under conditions for tissue culture. While I would not say they can't grow, I don't think they grow well. I believe that most fungal contamination of tissue culture that are observed are from other, non-laboratory, species.

Finally, although it is admirable to make a homemade flow cytometer (wow!), I don't think you will have much luck identifying different yeast strains using that instrument unless you have some way of staining cells for distinct features or have very good resolution to distinguish morphologies (even with that you will have to know what distiguishes the strains which is not well documented). Or, perhaps I misunderstood the goal of the project. That said, have fun with the project.

Yea - buddy is a product engineer for a med devices company. They scrapped a bunch of high-end-but-outdated equipment (bad quarter?) and he picked it up for a song. I think the end game is a little more ambitious than cell-counting overkill, but we have to start somewhere.

We do have the capability to do staining, have a full UV rig for the scopes, etc and a few microbiologist friends who will "work" for beer. However, I'd love to get some input from you guys. Shoot over suggestions and we'll try them out, report back, and even snap some photos.

I've gone through a few articles implying that yeast cell surface structures might vary by strain. I've also read that yeast cells show differences in autoflorescensce, especially when excited by uv light in the 260-290 nm range (apologies if I'm off - going from memory). The gotcha is that actual brewing yeast strains tend to be hard to differentiate (as opposed to everything else). We're also using ccd/CMOS instead of photomultiplier tubes, so we'll see how that goes.

My initial goal is to see of folks can give us a jump start or are willing to do some correspondence. I know it's lazy, but would love to skip some of the self discovery (e.g spending 6 months cataloging the fingerprints of wlp001 vs 005 vs 320) so that we can zoom in on specific traits.

Here's an easy place to start though ... Do you folks recommend any companies for glassware. We have 10 stepper motors, 3 scopes, and 0 petri dishes, flasks, or pipettes. And yes, I realize it's a weird problem to have.

brewguyver said:

I've gone through a few articles implying that yeast cell surface structures might vary by strain. I've also read that yeast cells show differences in autoflorescensce, especially when excited by uv light in the 260-290 nm range (apologies if I'm off - going from memory). The gotcha is that actual brewing yeast strains tend to be hard to differentiate (as opposed to everything else). We're also using ccd/CMOS instead of photomultiplier tubes, so we'll see how that goes.

My initial goal is to see of folks can give us a jump start or are willing to do some correspondence. I know it's lazy, but would love to skip some of the self discovery (e.g spending 6 months cataloging the fingerprints of wlp001 vs 005 vs 320) so that we can zoom in on specific traits.

Here's an easy place to start though ... Do you folks recommend any companies for glassware. We have 10 stepper motors, 3 scopes, and 0 petri dishes, flasks, or pipettes. And yes, I realize it's a weird problem to have.

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I'm not sure the beer yeast strains you mentioned have been adequately characterized to give you a "fingerprint" of cell surface proteins that are amenable to immunostaining. Same goes for intracellular proteins, if you are going that route (cell surface would be much easier).

I don't know if you have any recourse other than for discovery of uniquely expressed cell surface/intracellular markers. White Labs and Wyeast would be the ones to ask about this.

As for glassware, any of the common lab supply giants should be a good place to start (VWR, Fisher, etc.)

+1 to Broadbill.