How are viral plaque assays useful?
Plaque assay Plaque-based assays are the standard method used to determine virus concentration in terms of infectious dose. Viral plaque assays determine the number of plaque forming units (pfu) in a virus sample, which is one measure of virus quantity.
What is the importance of a plaque assay in microbiology lab work?
Plaque assay is one of the widely used approaches for determining the quantity of infectious virus in a sample. Only viruses that cause visible damage to cells can be assayed in this way. Plaque assay was first developed to calculate the titers of bacteriophage stocks.
How is plaque assay used in determining the virus titer?
The titer of a virus stock can be calculated in plaque-forming units (PFU) per milliliter. To determine the virus titer, the plaques are counted. To minimize error, only plates containing between 10 and 100 plaques are counted, depending on the size of the cell culture plate that is used.
What is the principle of plaque assay?
The plaque assay (Figure 2) is based on incorporation of host cells, preferentially in log-phase growth, into the medium. This creates a dense, turbid layer of bacteria able to sustain viral growth. An isolated phage can subsequently infect, replicate within, and lyse one cell.
What is a plaque assay and how is it performed in the laboratory?
In a plaque assay the host cells and virus are incubated together for a short time to allow the virus to attach to and enter the host cell. Then the mixture in plated within a semi-solid agar. This semi-solid agar is poured onto a “bottom agar” that serves to supply adequate nutrients for the host cell.
Why do we need to quantify viruses?
Viral quantification involves the counting of viruses or viral molecules in a known volume to determine their concentration. It plays an essential role in studies carried out in the fields of recombinant protein production, viral vaccine production and infectious disease.
What is a plaque assay in microbiology?
A plaque assay can be used to enumerate viruses that lyse their host cells. In a plaque assay the host cells and virus are incubated together for a short time to allow the virus to attach to and enter the host cell. Then the mixture in plated within a semi-solid agar.
What is a plaque in microbiology?
plaque, in microbiology, a clear area on an otherwise opaque field of bacteria that indicates the inhibition or dissolution of the bacterial cells by some agent, either a virus or an antibiotic. It is a sensitive laboratory indicator of the presence of some anti-bacterial factor.
What types of assays are used to detect viral nucleic acid?
Assays that detect viral nucleic acids are based upon the principles of PCR or nucleic acid hybridization, are extremely sensitive, and are specific for a particular virus. Viruses have evolved alongside humans for as long as both have existed.
What is the limitation of plaque assay?
Some disadvantages associated with the plaque reduction assay are (a) the length of time required to develop and count plaques, (b) day-to- day variation in plaque numbers resulting from changes in cell sensitivity to IF and virus, and (c) subjective determination of what constitutes a plaque when certain viruses are …
What is phage therapy used for?
Phage therapy (PT) is also called bacteriophage therapy. It uses viruses to treat bacterial infections. Bacterial viruses are called phages or bacteriophages. They only attack bacteria; phages are harmless to people, animals, and plants.
Is the method used to check the viral titer?
Viral plaque assay is one of the most widely used methods in virology to purify a clonal population of virus or to determine viral titer [36-40].