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# Growth of HPV is monitored: 10^9 cells and 10^6 viruses in one mL were incubated. Following one infectious cycle, a direct cound and plaque assay...

Growth of HPV is monitored: 10^9 cells and 10^6 viruses in one mL were incubated. Following one infectious cycle, a direct cound and plaque assay were performed. Direct count: mixture diluted by a factor of 1000X after which beads were added to obtain a final concentration of 1x10^4 beads/mL. A microscopic FOV showed 20 beads, 150 virions. In the plaque assay, 67 plaques observed on a plate on which 0.1mL of a 10^-5 dilution was assayed.

I have answered the first 7 questions which i will post here and need help with the last 5.
1. What was the initial multiplicity of infection = 10^-3
2.According to the direct count, what was the volume observed in a FOV? 0.002mL
3. According to the direct count, what was the no. of virus/mL after the 1st infectious cycle? 75 000 virus/mL
4. According to the direct count, what was the burst size after 1 infectious cycle? 0.075
5. According to the plaque assay, what was the no. of virus/mL after 1st infectious cycle? 670
6. According to the plaque assay, what was the burst size after 1 infectious cycle? 0.067
7. What percentarge of the viruses obtained after hte first infectious cycle are non infectious? 48%

8. What was the new multiplicity of infection (of infectious viruses) after the 1st growth cycle?
9. How many infectious cycles, including the first one, could be completed under the above described conditions?
10. After the last infectious cycle a 10^-8 dilution was made on the supernatant. If 0.1 mL of this dilution is applied to a monolayer of cells, how many plaques would you expect?
11. What would the total number of viruses be after the last infectious cycle?
12. How many viruses would you expect to observe in the FOV of the above described microscope for a 10^-7 dilution of the supernatant after the last infectious cycle?

The way to approach this... View the full answer

8. After 1000X dilution of your original stock for direct count, i.e. 1 l of stock and 999 l of
media or broth, total 1ml, it contains 104 beads (i.e. 10 beads per 1 l). Of which, 20

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