a. Let’s say for example that a milk sample has 10,000 bacteria per milliliters. If 1 mL of this sample were plated out, these would theoretically be 10,000 colonies in the Petri plate. Discuss and explain the serial dilutions of this example. b. The disk diffusion method was used to evaluate 3 disinfectants. The results were as follows: Solution Zone of inhibition X 0 mm Y 5 mm Z 10 mm How would you interpret? Provide inference.

a. Let’s say for example that a milk sample has 10,000 bacteria per milliliters. If 1 mL of this sample were plated out, these would theoretically be 10,000 colonies in the Petri plate. Discuss and explain the serial dilutions of this example. b. The disk diffusion method was used to evaluate 3 disinfectants. The results were as follows: Solution Zone of inhibition X 0 mm Y 5 mm Z 10 mm How would you interpret? Provide inference.

Biomedical Instrumentation Systems

1st Edition

ISBN:9781133478294

Author:Chatterjee

Publisher:Chatterjee

Chapter5: Biomedical Electronics: Digital

Section: Chapter Questions

Problem 5Q

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A pure bacterial culture of unknown concentration was diluted to determine the concentration of viable bacteria in the original culture. Serial dilutions were performed as 1. diagrammed below. Each dilution tube contained 400 ul of diluent and 100 ul was transferred into each tube. TSA plates were inoculated with 100 µul from the last three dilution tubes. a. What is the dilution between each tube shown in the diagram below? Express your answer as a ratio. b. What is the total dilution of tube number 5? Express your answer as a ratio. c. What is the concentration of viable bacteria in the original culture? Express your answer using scientific notation and the units CFU/ml. d. What is the concentration of viable bacteria in tube number 2? Express your answer using the units CFU/ml. e. If you inoculated a TSA plate with 250 µl from tube number 5, how many colonies would you expect to see after the plate was incubated? 1 2 3 5 423 80 13 Number of colonies
The figure above depicts an agar cube with a side length of 13\, \text{mm}13mm13, start text, m, m, end text. In an experiment, students submerged the cube in red dye for 121212 hours. The red dye permeated 1\, \text{mm}1mm1, start text, m, m, end text on each side, as indicated by the shading in the figure. Volume of a rectangular solid: V = lwhV=lwhV, equals, l, w, h Calculate the volume of the agar cube that remained unpenetrated by the red dye.
Consider the sterilization of a sodium gluconate production medium in the holding section of a continuous sterilizer. Assuming constant temperature, the specific death rate constant of the contaminant is 20 s-1 . If the average residence time in the holding section is 10 seconds, calculate the Del factor for the following and explain the results. i. For Pe = 400 ii. For Pe = 400, assuming plug flow iii. For Pe = 100 iv. For Pe = 100, assuming plug flow
volume of the quasi-steady-state culture was V0= 500 L, and the nutrient solution containing glucose was added at a constant flow rate of F = 50 L/h.Data: X0 (at the beginning of feeding) = 20 g/L, S0 = 300 g/L, max = 0.2 h-1, KS = 0.5 g/L and Y x/s= 0.3 g/g a) Determine the volume of the culture at t = 10hb) Determine the concentration of glucose at t = 10 hc) determine the concentration and total mass of cells at t = 10 hd) If product is associated with growth with α = 1.5 and P0 = 0.1 g/L, determine the concentration of product at t = 10h. (answer:P = 67,55 g/L)
A pure bacterial culture of unknown concentration was diluted to determine the concentration of viable bacteria in the original culture. Serial dilutions were performed as 2. diagrammed below. A volume of 500 µl was transferred into each tube. TSA plates were inoculated with 100 µl from the last three dilution tubes. a. If the dilution between each tube is 102, what is the volume of diluent in each of the 5 dilution tubes? Provide the volume using ml as the units. b. What is the total dilution of tube number 4? Express the total dilution using scientific notation. c. What is the concentration of viable bacteria in the original culture? Express the concentration using scientific notation and CFU/ml as the units. d. If you inoculated a TSA plate with 1.0 ml from dilution tube 4, how many colonies would you expect to form on the plate after incubation? e. If the original culture had a volume of 50ml, what was the total number of viable bacteria in the 50 ml of the original culture? 1 2 3…
An amino acid of interest was produced in a fed-batch culture using glucose in the feed medium. The initial volume of the quasi-steady-state culture was V0= 500 L, and the nutrient solution containing glucose was added at a constant flow rate of F = 50 L/h.Data: X0 (at the beginning of feeding) = 20 g/L, S0 = 300 g/L, max = 0.2 h-1, KS = 0.5 g/L and Y x/s= 0.3 g/g a) Determine the volume of the culture at t = 10hb) Determine the concentration of glucose at t = 10 hc) determine the concentration and total mass of cells at t = 10 hd) If product is associated with growth with α = 1.5 and P0 = 0.1 g/L, determine the concentration of product at t = 10h.
Apple puree was analyzed for petulin by HPLC-MS-MS after SPE clean-up. The procedure was 10.0g of puree + 10μl of a 10μg/ml solution of isotopically labeled petulin as internal standard were treated with 10.0ml of pectinase and acetic acid, centrifuged, and filtered. Four ml of the filtrate was passed through a SPE cartridge. The petulin was eluted with 2.0ml of ethyl acetate. The sample was evaporated to dryness and the residue dissolved in 1.0ml of the mobile phase. The analyte signal was 127 and the internal standard 197. Calculate the concentration of petulin in the sample in μg/g (RRF=1).
Serial dilution = previous dilution x dilution 11 mL [2] 3 mL Colony count: 100 0.1 mL sample [1] 9.9 mL 5 mL 0.1 ml. Cokony count Dilution: 10-1 10-3 [3] 150 Dilution factor (DF): [4] [5] [6] Compute for the CFU/mL of the sample. Show your solution and express your final answer to 2 significant figures.
Imagine you have been given a liquid culture of yeast with a starting concentration of 3.67 x 10' cells/ml and are asked to carry out the sample dilution process shown in the figure below. 100μl 100μl 100μl 100μl 100μl 0.9ml 0.9ml 0.9ml H2O H₂O 6.9ml 0.9ml H₂O H₂O H₂O Original 10-1 102 10-3 104 Culture 105 100μl 100μl 100μl Plate A Plate B Plate C a. How many colonies should have been present on Plate A in this example? - Answers must be whole numbers as partial colonies are not expected. b. Imagine you carried out the same dilution scheme shown in the figure above, but now, you do not know the concentration of the original culture. If you counted 163 colonies on Plate B, what is the concentration of cells/ml in the original culture?
1. (2.5 pts) A pure bacterial culture of unknown concentration was diluted to determine the concentration of viable bacteria in the original culture. Serial dilutions were performed as diagrammed below. Each dilution tube contained 400 ul of diluent and 100 ul was transferred into each tube. TSA plates were inoculated with 100 µul from the last three dilution tubes. a. What is the dilution between each tube shown in the diagram below? Express your answer as a ratio. b. What is the total dilution of tube number 5? Express your answer as a ratio. c. What is the concentration of viable bacteria in the original culture? Express your answer using scientific notation and the units CFU/ml. d. What is the concentration of viable bacteria in tube number 2? Express your answer using the units CFU/ml. e. If you inoculated a TSA plate with 250 µl from tube number 5, how many colonies would you expect to see after the plate was incubated? 1 2 3 5 423 80 13 Number of colonies
Describe how you would prepare a dilution series of a 1 x 107 CFU/mL culture to the 10-8 dilution using only 4.5 mL diluents in tubes. What would be the theoretical cell count if 0.1 mL of the 2nd and 4th dilutions were each plated?
Time point (min) Absorbance of culture at 660nm Approximate cell concentration Approximate # cells in 1mL extract 0 0.298 1.49 x 108 cells/mL 1.49 x 108 cells 10 0.316 1.58 x 108 cells/mL 1.58 x 108 cells 20 0.374 1.87 x 108 cells/mL 1.87 x 108 cells 30 0.429 2.145 x 108 cells/mL 2.145 x 108 cells 40 0.512 2.56 x 108 cells/mL 2.56 x 108 cells 50 0.544 2.72 x 108 cells/mL 2.72 x 108 cells 60 0.607 3.035 x 108 cells/mL 3.035 x 108 cells a. Using these data, prepare a growth curve of this strain ofEscherichia coli (E. coli).b. Estimate the doubling time for this strain of E. Coli. Clearly showhow you estimated this value from the empirical data presented.