Calculate the viral titer of an experiment performed yielding a pfu of 279 from plating 1.0 ml of the 10-5dilution.  Show all work and write the answer in scientific notation.

Draw a dilution scheme for a dilution of phage from 1.5 x 1010 PFU/mL to 1.00 x 102 PFU/mL. Achieve this serial dilution considering the following: The volumes of each dilution should be 1.0mL. It is not advisable to perform any dilutions > 1/100. The first dilution in any titre determination of stock phage should use 10µl or less of stock.

Determine the concentration of L. monocytogenes enumerated from the apple slice based on the information below. You must draw your serial dilution and show your mathematical calculation.  The apple slice (12 g) was first mixed with 108 ml of sterile 0.1% peptone water. After, 1 ml was added to tube containing 9 ml of sterile 0.1% peptone water. Process was repeated with two additional tubes. 1 ml was pipetted from tubes 2 and 3 onto MOX media. Plates were incubated at 37 for 48 hours. The pictures below show the plates from tube 2 (left) and tube 3 (right).

Shown below is a set of cell culture plates for a plaque assay.  The assay was performed by preparing dilutions of a virus stock with the dilution factor for each prepared dilution listed below the sample.  0.5 mls of each dilution was added to confluent (fully covered) monolayers of cells on each plate.  The virus used for the assay had a titer of 2 x 1010 Plaque forming units (PFU) per ml. Only 1 set of the above plates would have a number of plaques on it that would be both easy to count and high enough to be statistically relevant.  Which dilution set would it be and about how many plaques would there be on the plates of that dilution set.

You will use a Calf Thymus DNA standard stock solution (1 mg/ml) to prepare a standard curve. Calculate volume of stock solution in ul, needed to prepare 10 ug/ml dilution (final volume 1.0 ml).

what are the volume dilution and dilution factor for bacteriophage A，B，C

How is 10^4 derived? Please show all calculation steps. # of cells per mL = (Average)*DF*10^4

AE, 62, Male Wt: 75 kg, Ht: 150 cm Orders: Penicillin G Potassium            10,000,000 Units Sterile water for injection                              qs Make a 250,000 U/mL solution.   The package insert states If Penicillin G Potassium 10,000,000 Units is reconstituted with 44 mL sterile water, a solution of 200,000 U per mL will be obtained.   What volume of sterile water would you use to reconstitute the penicillin G potassium in order to make the ordered solution?

A 10-2 is performed on a culture of bacteria in order to perform viable plate counts. From the dilution, *0.1 mL* of solution is plated on solid media, and 61 colonies of bacteria grow on the plate.  Assuming each colony came from a single bacterium, how many bacteria are in a single mL of the original culture?

A plaque assay is performed beginning with 1 mL of a solution containing bacteriophages. This solution is serially diluted 3 times by combining 0.1 mL of each sequential dilution with 9.9 mL of liquid medium. Then 0.1 mL of the final dilution is plated in the plaque assay and yields 12 plaques.What is the initial density of bacteriophages in the original 1 mL? Enter your answer to two significant figures ( for example: 1.1 * 10^2)