Questions tagged [yeast]

Yeasts are a polyphyletic group of unicellular fungi. Usually the term yeast is used synonymously with baker's yeast - Saccharomyces cerevisiae.

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How can I measure the population growth of yeast?

I will soon have to carry out an experiment. I want to estimate the rate of growth of a population of yeast, although I don't know if it is possible to at least estimate the number of yeast bacteria ...
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Does the process of making a sourdough starter involve Darwinian selection?

In essence - to make a sourdough starter: Put flour and water in a jar, and leave it in a warm place overnight Divide the remaining mixture in half, throw out half, add half as much flour and water ...
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Can viruses stabilize and increase the shelf life of wine and other foods?

When you make wine, you use the yeast Saccharomyces cerevisiae to ferment sugary juices. After you're done, you want to avoid them doing anything by using some chemicals etc. There are also other ...
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Yeast absorption of different spectra of light

I'd like to monitor the growth of a yeast population by shining light through it and monitoring the change in light that gets through as it grows. I'm not sure if I should use IR, or any particular ...
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Why do yeast ferment Equal sweetener

I had my students conduct a fermentation experiment manipulating sugar amounts (number of sugar packets in solution) and measuring CO₂ production via capture in a balloon and measuring circumference (...
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What are the best plants to cultivate yeast from?

I know that cultivating yeast from potatoes yields a good brewing yeast and that forms of wheat make good baking yeast, however; I have not seen much information on other useful plant yeast cultures. ...
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Species diversity in cheese and yoghurt?

There have been studies on the number of species on humans and in various other environments. I was wondering how many species including: viruses, bacteria, yeasts, and fungi inhabit ordinary farm ...
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Rice left in water for several months - what biological reactions or growths would occur?

In an attempt to make a hair care product, uncooked white basmati rice was left in an air-tight container half filled with tap water for several months. When opening the container, the smell was ...
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856 views

Meaning of “f.a.” in the species name

What does "f.a." stand for in the name of the "Wickerhamomyces menglaensis f.a." yeast species mentioned in this article https://ijs.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0....
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Clarification of method notation in yeast cultivation method

I'm reading a paper about yeast culture and in the methods, it says: Then $5$ ml of sterile $M/15\ KH_2PO_4$, was added to the slant, What is the meaning of $M/15$?
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Is it normal to see yeast cells stacked in the Z axis when counting yeast?

I just got started with yeast cell counting and was surprised to observe yeast cells that are at different z axis depths at 400x. That is, by adjusting the focus (not the x/y stage) I can make some ...
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Infecting yeast with viruses

Is there any virus, either natural or engineered, known to infect yeast through mechanisms similar to phages/human viruses, that is, by horizontal contamination mediated by extracellular viral ...
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How is Saccharomyces cerevisiae grown on acetate and ammonium able to produce TCA intermediates?

I am working with a metabolic model of Saccharomyces cerevisiae and I am studying its growth on acetate and ammonia. I am performing Flux Balance Analysis to compute the growth rate and then I am ...
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How can I estimate the total number of yeast cell in a medium?

So I want to run an experiment with yeast. I want to monitor the population as close as possibly in regards to its size. I am aware I could use a colorimeter or such, but I can only get a microscope. ...
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Continuous (yeast) culture system satisfying multiple criteria

There are multiple ways yeast cells can be grown in liquid cultures. Batch cultures are easy to prepare but cell density, medium composition and physiology change over time Chemostats allow to ...
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What is the practical difference between SC, SD and CSM?

Is there some logic to how SC, SD and CSM yeast dropout media differ from each other? I have encountered these three formulations in Sunrise Science Products' catalog, and it appears that the ...
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Primer design for PRP24-TAPtag

I have a problem with my proteomics homework. I was asked to design primers used to create a homologous recombination box to create PRP24-TAPtag yeast. I know that homologous regions should be 40-50nt ...
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128 views

Can a plasmid cause cancer? [closed]

Can a plasmid cause cancer? According to wikipedia, plasmids are normally present in bacteria They (plasmids) are normally present in bacteria , and sometimes in eukaryotic organisms such as yeast [...
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The effect of sugar on rate of yeast Respiration

In my experiment, I am investigating the effect of different types of sugar on the rate of respiration of immobilized yeast (yeast trapped in calcium alginate balls). I am looking at glucose, fructose,...
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Where do I get an annotation file for yeast genome with ENSEMBL ids?

Even the annotation files hosted on the Ensembl site have systematic names (starting with Y..) instead of ENSEMBL ids (starting with EN..). I bet there would be a place where I can get an annotation ...
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87 views

How to measure the length of mitochondria from z stack fluorescent microscopy image?

I have been working on yeast cells to analyse the effect of DNA damaging agents on mitochondrial structure. I have imaged my culture treated with MMS for a period of 6 hours and while observing the ...
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What concentration of sugar is optimal for baker's yeast fermentation?

I'd like to do an experiment on what concentration of sugar would be best for fastest yeast fermentation. I'm thinking to put some active dry yeast into different concentrations of sugar water and ...
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456 views

Where do kombucha SCOBYs get nitrogen?

Kombucha can be brewed even with tiny amounts of inocculate, such as the little bit of sediment at the bottom of store-bought kombuchas. Over 1-2 weeks, this can grow into an inch thick film covering ...
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How do I improve expression using the GAL1 promoter in S. cerevisiae above the “leaky” level I'm currently seeing?

I am attempting to express GFP in S. cerevisiae using the GAL1 promoter. I always grow an uninduced (in dextrose based SD medium) culture alongside my induced (in galactose based SD medium) culture. ...
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Can yeast survive without mitochondria?

Some yeast cells have very low mitochondria copy number (see number of mitochondria in non budding cell, you can count mtDNA). This makes them susceptible to fluctuations, and one can conceive that ...
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Yeast contamination with fungus patch

I am working on yeast mutant and I am observing their sporulation efficiency on agar plates. One of my plates got some dark green small fungus patches. I can't grow yeast again and dump this one with ...
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Why do some yeast flocculate on top an other at bottom?

When fermenting beer normally after the fermentation has completed the yeast flocculate and drop to the bottom. However occationally they form a foamy layer on top of the beer. The difference is ...
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Protein expression in K. lactis system

I am trying to express a protein in K. lactis Protein Expression Kit (E1000S - NEB) in the way that the protein is secreted into the medium. I know that I can get some protein but it is not active. As ...
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Yeast transformation plate confluent with growth

I have problem with yeast transformation. I tried to transform pyes3-tryp(my insert inside) into INVsc1 yeast cell by following the protocol in the manual for few times but failed(confluent with ...
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Is the CMV promoter active in yeast?

I wish to transfect yeast and want to control my efficiency. So I thought to use pEGFP-N1 as control. The EGFP is driven by a CMV promoter. Can yeast read CMV promoters. Thanks Hermann
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Is hydrochloric acid suitable for pickling food?

I was wondering whether it is possible to pickle food using hydrochloric acid (HCl), rather than acetic acid. I am not very familiar with the biology of the fermentation process involved in pickling ...
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Why would yeast grow but not produce alcohol?

I'm studying for my intro to microbiology test and I have a question asking why a culture of yeast responsible for producing alcohol would be growing, but not producing alcohol? The multiple choice ...
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Why does yeast react the way it does to water combined with sugar?

I almost wanted to ask this in Cooking SE, but thought it would be better fit here. So I understand than when you mix yeast with sugar and warm water, you get CO2. When using baking powder, it's a ...
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Pichia pastoris and ornithine

Can Pichia pastoris (species of yeast used for recombinant protein) produce the non-protein amino acid Ornithine? Or does it express ornithine at all?
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What is the rate of mRNA decay in saccharomyces cerevisiae?

I am just looking for a number whether that is a mean or an estimate. I am having trouble finding this value on papers because the papers mention only the methods for calculating such a value. Is ...
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337 views

Yeast Strain with squalene synthase / farnesyltransferase (ERG9) gene deleted

I was interested in obtaining a yeast strain without the enzyme farnesyltransferase (Which catalyses conversion of FPP to Squalene). The Euroscraf database has thousands of yeast strains with ...
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Y285 Yeast Strain: Where to obtain from?

Often I see yeast strains mentioned like Y285 or Y301 etc. in papers. Is this some sort of universal notation? (Link to poster: https://ddd.uab.cat/pub/tfg/2014/119349/TFG_narcisferrerledo.pdf) How ...
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Enzyme Inhibitors: Using in vivo in yeast

I find listed on the Sigma-Aldrich site a large list of enzymes & corresponding inhibitors. e.g. For the enzyme squalene synthase the inhibitor listed is "Zaragozic acid A trisodium salt" Would ...
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Using PGAL10 promoter to overexpress specific yeast genes: How to?

I was reading a poster about expression boosting for Artemesinin production in yeast and it had this line: PGAL1 and PGAL10 have been used for the overexpression of all genes from the ...
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Earliest to use media after autoclaving?

I am autoclaving media to use later to inoculate yeast. How much time do I have to wait before using the media and adding the culture? Can I use it a few hours after autoclaving?
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identifying which SNPs sit in TFBS (Yeast)

i have a set of ~11k SNPs for Saccharomyces cerevisiae, baker's yeast and i would like to identify which ones of these sit in transcription factor binding sites and if they do information on the ...
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The effects of auto-brewery syndrome

Why are some people affected so differently by auto-brewery syndrome differently if the syndrome seems to be caused by the single organism saccharomyces cerevisiae? It is known that the syndrome has ...
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Why did the yeast rise?

Here are the notes I made for an experiment I was doing (I didn't put it here as it is too long) (please ignore the numbers at the end of the pdf file) The graph looks like this: As you see on the ...
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Relationship between turgor pressure and osmotic pressure?

I would like to know if there is a relationship between osmotic pressure (inside and outside of a cell) and turgor pressure. If so, is there a way to formalize it mathematically? Thank you in advance,...
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Can yeast in a primary fermentation of wine be used as a source of yeast for new fermentation?

So if I were to pitch bread yeast, and get to primary fermentation, which as I understand it, is the point at which regular cellular respiration can no longer continue due to a lack of oxygen , which ...
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yeast protein secondary structure

i have a fasta file of yeast orfs (from the SGD database) and i need to find out(predicted) secondary structure/classification for all of them (so ~6K queries and doing this by hand on numerous ...
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Mitotic chromosome condensation screen

If I want to screen for mutant yeast (S. cerevisiae) colonies that have defects in mitotic chromosome condensation, can I screen for colonies arrested in Mid-M phase? Would that work?
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861 views

Evolution home experiment?

If I were to take bakers yeast and put it in medium of minimal sugar(whatever quantity that would be) and rice(for a source of starch), could the yeast have a "evolutionary leap" and adapt to use the ...
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How does DNA damage cause ageing in yeast?

As I understand it, in yeast ageing there is daughter cell and mother cell. The daughter cell is has newly "fresh" DNA and mother cell dies after some counts of replication. What happens to the ...
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Sources for common laboratory Saccharomyces strains?

I'm used to working with bacteria - some of the more common laboratory strains sometimes come with an order from some vendors. What's the most convenient source to order common straings of ...