You are tasked with enumerating the viral load of an unknown…

You are tasked with enumerating the viral load of an unknown sample. You begin your investigation by serially diluting the sample resulting in the following dilutions: 10-2, 10-4, and 10-6. You spread 80µl of each dilution onto a separate nutrient agar plate and incubate for 48 hours. Upon examining the plates for the 10-2 and 10-6 dilutions only. You observe the following results:  10-2: 125 PFU  10-6: 90 PFU  Calculate the phage titer for these two agar plates. Report your final answer in the correct notation and with appropriate units.

After performing Gelatin Hydrolysis test on two different or…

After performing Gelatin Hydrolysis test on two different organisms in separate test tubes labeled 1 and 2, you observed the results. a) Which test tube shows positive result 1 or 2?  b) What enzymatic process does gelatin hydrolysis test for? c) Why do we use an ice-bath in this test?   

You perform a serial dilution series of the same species of…

You perform a serial dilution series of the same species of bacteria onto identical agar plates, all incubated for 24 hours at the same temperature. Shown from upper left to lower right are bacterial dilution concentrations of 10-2, 10-4, and 10-6. Given that the agar plates and bacterial sample were identical before diluting, what is the best explanation for the difference seen in bacterial colony size amongst the three plates?