You have developed your own set of primers for the identification of Helicobacter pylori, the pathogenic bacterium responsible for the development of peptic ulcer disease and gastric adenocarcinoma. Your primers amplify a 161 bp fragment of the vacA gene which is only found in H. pylori. You culture bacteria from gastric biopsies, extract the DNA, run the PCR, and run the gel elctrophoresis according to standard techniques. An image of the gel electrophoresis is below.
The lanes on your gel contain the following:
M) Mass Ladder to estimate size
1) Positive Control using DNA from a lab grown strain of H. pylori
2) Biopsy Sample #1
3) Biopsy Sample #2
4) Biopsy Sample #3
5) Biopsy Sample #4
6) Negative Control
What is the interpretation of your gel?
a. All biopsy samples are positive for H. pylori
b. The primers were improperly designed and did not amplify a fragment of the correct size.
c. All biopsy samples are negative for H. pylori
d. The PCR was contaminated and cannot be interpreted