Yeast Colony Counting
Yeast Colony Counting - Related Videos
09:04
Yeast Colony Embedding Method
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Cited by 7 •
2011
A method for embedding yeast colonies allowing sectioning for light and electron microscopy. This protocol allows determination of the distribution of sporulated cells and pseudohyphal cells within colonies providing a new tool toward understanding the organization of cell types within a fungal community.
03:55
Counting Colony Forming Units (CFUs): Quantifying Bacteria from Fly Bodies
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2023
Drosophila microbiota impacts the animal's development, immunity and physiology. This video describes a method to quantify bacteria from flies by determining the colony forming units from whole body preparations. The featured protocol demonstrates the technique with flies, reared under gnotobiotic conditions using four bacterial species.
08:30
Yeast Maintenance
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2023
Research performed in the yeast Saccharomyces cerevisiae has significantly improved our understanding of important cellular phenomona such as regulation of the cell cycle, aging, and cell death. The many benefits of working with S. cerevisiae include the facts that they are inexpensive to grow in the lab and that many ready-to-use strains are now commercially available. Nevertheless, proper maintenance of this organism is critical for successful experiments. This video will provide an overview...
05:20
Yeast Two-Hybrid Assay to Determine Protein Self-Association in Yeast Cells
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2025
This video demonstrates the yeast two-hybrid assay to detect specific protein self-interactions. In this assay, the protein of interest is tagged to two domains of a transcription factor that encodes the β-galactosidase enzyme. When the two proteins interact, this causes transcription and translation to form the enzyme, which is then detected using a biochemical assay.
08:30
Yeast Transformation and Cloning
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2023
S. cerevisiae are unicellular eukaryotes that are a commonly-used model organism in biological research. In the course of their work, yeast researchers rely upon the fundamental technique of transformation (the uptake of foreign DNA by the cell) to control gene expression, induce genetic deletions, express recombinant proteins, and label subcellular structures. This video provides an overview of how and why yeast transformation is carried out in the lab. The important features of yeast...
FAQs
The reported unit is a colony-forming unit (CFU), not necessarily one individual cell. A visible colony may originate from a single viable yeast cell or from a cluster that remained together during handling. Consequently, the result estimates the viable population in CFUs, while the actual number of cells can be higher when yeast cells associate or clump.
Clumping can cause several viable yeast cells to produce one visible colony instead of separate colonies. The count therefore reflects the number of colony-forming units that develop from individual cells or groups, rather than automatically representing every cell present. Recognizing this limitation is important when comparing samples or interpreting estimates of viable yeast density.
Dilution accuracy directly affects the population estimate because an error in the prepared sample is carried into the plate result. Incubation must also provide suitable conditions for viable yeast cells to multiply and form visible colonies. If either factor is poorly controlled, the recorded count may not accurately represent the viable population in the original sample.
A typical workflow begins by diluting the yeast-containing sample, then distributing the prepared dilution across or within solid agar medium by spreading or pouring. The plate is incubated under suitable conditions until colonies become visible, after which the colonies are recorded as colony-forming units. Careful handling throughout supports a more reliable estimate.
The method is useful when researchers need an estimate of viable yeast population rather than only a general indication that yeast is present. Its applications include measuring culture density, following changes during growth analysis, monitoring contamination, and supporting quality control. These uses connect colony formation on agar with practical assessment of biological samples and processes.
Repeated colony counts can provide measurements of viable yeast population at different points in a growth study. Comparing those measurements helps researchers examine changes in culture density over time. Because the method records colonies formed by viable cells or cell clusters, interpretation should account for dilution accuracy, incubation conditions, and possible clumping when evaluating growth patterns.