Plaque Demonstration Kit Results and Analysis Part A Collect and record data aft
ID: 278406 • Letter: P
Question
Plaque Demonstration Kit Results and Analysis Part A Collect and record data after agar layer plates have been incubated 18-24 hours at 37"C. 1. Count plaques on each plate (If possible) and record the number in the table below. 2. Examine the characteristics of several individual plaques (not crowded by others) produced by T4 and T4r Record only the morphology that you decide is typical. Plaque Counts and Plaque Morphology Plaque Counts Plaque Morphology Plate and Phage Expected calDiam. (mm) Center Margin Plate 1: Control Plate 2: T4 Plate 3: T4 Plate 4: T4r Plate 5: T4r The stock suspensions of T4 and T4r have a plaque assay value (effective titer) of approximately 10)mL. This means that one 10,000* 100** 10,000* 100** I5 S 79 milliliter is expected to produce about 10,000 plaques if each phage particle generates a plaque. These represent 1/100 dilutions of the phage stock suspensions. Since each of the two 9:1 (broth:phage) dilutions reduces the concentration of phage particles by 1/10, the series results in 1/10 x 1/10-1/100 final dilution. Part B Test your comprehension of this exercise by answering the following questions 1. Are all of the plaque counts equally reliable? Why or why not? 2. What is the practical value of serial dilution? 02004 Carolina Biological Supply CompanyExplanation / Answer
1. here the plaque counts are not reliable. the serial dilution may not be proper. or all the phages in the titer are infecting the bacteria. generally, each phage is supposed to produce a plaque.
when you observed1008 plaques/ml of the stock solution, 1/100 serial dilution is expected to give 100 plaques. [1ml (1008 phages) mixed in 100 ml broth. now 100 ml contains 1008 phages. when 1 ml is plated, (1008/100 =) 100 plaques are supposed to observe.]. however, here, you observed only 37.
2. practical value of dilution, when 1 ml phage mixed with 9 ml broth, it gives 10-1 dilution. (10 ml of broth contains 1 ml of stock)