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Is hydrochloric acid suitable for pickling food?

Short answer Weak organic acids are more effective for food preservation then strong mineral acids, mainly because undissociated weak acids can cross the cell membrane and disrupt cell physiology from ...
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9 votes
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Evolution home experiment?

Keep in mind that the citrate utilizing strain appeared after over a decade. Also, Escherichia coli could always metabolize citrate, but the citrate transporter that brings it into the cell is only ...
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8 votes
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Meaning of "f.a." in the species name

"Forma asexualis" as explained in another paper The authors favor the use of the expression forma asexualis (f.a.) in the description of anamorphic species of the genus Cystobasidium and this ...
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5 votes

How does DNA damage cause ageing in yeast?

In eukaryotic cells there is no difference between a mother and a daughter cell - the later is an exact copy of the mother cell. This is true for yeasts as well for example for human cells. The only ...
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4 votes
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What is the best current understanding of how yeast transformation works?

I have never worked much with yeast, but I can still give some answers: Salmon sperm is used as a the so called "carrier DNA". It is thought to bind to the yeast cell wall and thus prevents that the ...
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4 votes

Earliest to use media after autoclaving?

There is a relatively simple (and yet logical) answer: You can use the media as soon as they are cold enough for your desired culture temperature. So if you want to use the media at 30°C, there is no ...
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4 votes

How does DNA damage cause ageing in yeast?

Background to the different theories of ageing. This video, from a senior lecturer at the University of Liverpool who specialises in ageing, discusses the theories of ageing. He touches on the DNA ...
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4 votes
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How can I measure the population growth of yeast?

The standard way to measure growth in a liquid culture is to measure the optical density (OD) of the solution – basically, how cloudy it is. Bacteria or yeast in a solution will absorb light that ...
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3 votes

Is the CMV promoter active in yeast?

Yes (reference) While I found your question interesting this was pretty much the first hit when I typed "CMV yeast" in google scholar. You should really look there first before you ask!
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Enzyme Inhibitors: Using in vivo in yeast

This is usually the way this kind of inhibitors are used. There needs to be a way that they come into the cells (if they stay in solution and cannot reach their target they will be useless), but then ...
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3 votes
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Why does yeast react the way it does to water combined with sugar?

Yeasts are living organisms, they do not evaporate. However it is true that in most fermented food we eat, yeast are no longer there. So why is it so? It is not the reaction with sugar and warm water ...
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Relationship between turgor pressure and osmotic pressure?

Turgor Pressure(T.P) is defined as the amount of pressure inside a cell solely due to its water content, whereas Osmotic Pressure(Pi) is defined as the pressure required to stop osmotic flow between ...
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Can yeast in a primary fermentation of wine be used as a source of yeast for new fermentation?

Yes, it is possible to reuse yeast in both beer and wine fermentation - commercial brewers do it all the time for cost savings and batch reproducibility, and although I'm not as familiar with making ...
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3 votes
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Why does the stability of YAC increase with size?

This is a question which is not easy to answer, especially the 50.000bp number (which I haven't found anywhere in there literature). However, I found some evidence, partly derived from plant and ...
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3 votes
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Can yeast survive without mitochondria?

Basic answer: Yes, they can survive, but only if they do not need to undergo cellular respiration. I quote from Microbiological Research, Volume 169, Issue 2-3, p. 185-195: Mitochondrial DNA (...
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3 votes

Where do kombucha SCOBYs get nitrogen?

Short answer: Nitrogen fixation (i.e, atmospheric nitrogen) Longer answer: Nitrogen fixation is the process by which atmospheric nitrogen is converted to forms usable by further biochemical ...
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3 votes

How can I estimate the total number of yeast cell in a medium?

Determination of cell concentration using a microscope is usually done by using a hemocytometer, also called counting chamber or Neubauer-counting chamber. Basically, you count the cells in a defined ...
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3 votes
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Can viruses stabilize and increase the shelf life of wine and other foods?

There is at least one bacteriophage ("phage") that targets bacteria that spoil wine: The Gluconobacter phage GC1 is a novel member of the Tectiviridae family isolated from a juice sample collected ...
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2 votes

Sources for common laboratory Saccharomyces strains?

One very important resource is EUROSCARF. http://web.uni-frankfurt.de/fb15/mikro/euroscarf/ It is one of the very famous and dedicated strain repository for yeast (S. cerevisiae) strains. You can ...
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Downloading specific yeast genes in an automated manner?

These sequences do not have any standard i.d. The information in Saccharomyces Genome Database is also obsolete (2005) and does not have these identifiers. These sequences can be found here (in the ...
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2 votes

Yeast absorption of different spectra of light

Most of the loss of light being transmitted through individual cells is not absorbed, rather it is scattered (redirected from its original direction to a new one without loss of energy). There is ...
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2 votes

Why would yeast grow but not produce alcohol?

I think only b.) is true. a. I cannot find evidence that maltose is toxic to yeasts (and I would hardly believe it, because it is a glucose dimer), however I found evidence, that yeasts might need ...
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2 votes
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The effects of auto-brewery syndrome

The gut microbiome is extremely complicated, and almost anything related to it is only partially known, therefore prone to oversimplification. Trying to explain the phenomenon of gut fermentation ...
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2 votes

Earliest to use media after autoclaving?

If not using antibiotics or other additives, it's just a matter of medium being cold enough. If it's too hot, the yeast (or whatever you are inoculating) might get killed or heat-shocked, which you ...
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2 votes
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Yeast Strain with squalene synthase / farnesyltransferase (ERG9) gene deleted

Yeast strains have two mating types MATa (since it secretes a pheromone named 'a factor'), MATα (secretes pheromone 'α factor'). Both MATa and MATα strains are haploid and when they fuse together they ...
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2 votes
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Rice left in water for several months - what biological reactions or growths would occur?

It is likely a volatile organic compound (VOC) that is released as a by-product of microbial metabolism, although microbes can also produce some inorganic compounds, such as hydrogen sulfide (rotten ...
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  • 258
1 vote

How do I improve expression using the GAL1 promoter in S. cerevisiae above the "leaky" level I'm currently seeing?

There are a couple of things that are strange here. First, you have low expression in the presence of galactose. The GAL1 promoter is really strong, so that strikes me as odd. Even if it was leaky, ...
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  • 176
1 vote

Pichia pastoris and ornithine

Yes, it contains arginase. Thise enzyme converts arginine to ornithine and is probably part of the urea cycle. You might notice the arginase is listed as coming from Komagataella phaffii GS115, but ...
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1 vote

Using PGAL10 promoter to overexpress specific yeast genes: How to?

You're right about them being promoters, although it would be useful if you posted the link to the source of the sentence that you cite, so that we can read exactly how they are being used. A fairly ...
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1 vote

What concentration of sugar is optimal for baker's yeast fermentation?

When glucose and fructose are fermented separately, the uptake profiles indicate that both sugars are utilized at similar rates. However, when fermentations are conducted in media containing an equal ...
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