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Mycobacteriophages Isolated from Tropical Soils of Puerto Rico
Anaeli Shockey
Nicolle Rosa
Mentor: Dr. Rubin
Introduction
Mycobacteriophages are viruses that infect bacteria belonging to the Mycobacterium genus.
Introduction Two cycles:
Lyseogenic: Infects host, integrates genome and propagates with the host chromosome.
Lytic: Infects, copies DNA, makes new virions, lyses the cell and escapes.
Applications
Field of biomedice Elimination of antiabiotic resistant bacteria
Phage Therapy
Materials Agar plates
Sterilization filters
Syringes
Phage buffer
Microcentrifuge tubes
M. smegmatis culture
Disposable pipettes
1000µL and 100µL micropipettes
Vortexer
Centrifuge
Shaking Incubator
Methods
Isolate Phage
Prepare Filtrate
Plaque Purification
Web Pattern (dilutions)
High Titer Assay
SDS Gel
First Steps:
Enrichment
Harvesting
Plaque Purifications
Second Enrichment and Filtration
Enrichment Isolate a phage with the tip of a micropipette. Add in the same solution as the first enrichment and
follow the same procedure.
Filtration Follow the same four steps of the first harvesting which is
the filtering process.
Medium Titer Assay: Dilutions From the filtration, dilute four phage solutions.
In four tubes labeled from -1 to -4, add 90uL of phage buffer.
To the -1 tube, add 10uL of the filtration and centrifuge.
To the -2 tube, add 10uL of the -1 tube and centrifuge.
Repeat this process up to the -4 tube.
Add 10uL of each tube (including the filtration) to a sample of bacteria.
Let sit for 15 – 30 minutes.
Add top agar to the bacteria and spread the solution on a properly identified plaque.
Incubate.
Medium Titer Assay
Result: Web pattern (arrangement of plaques in which almost all of the bacteria was lysed)
Add 6mL of phage buffer to plaques #1 -3, #2 -4, and #3 -4
Place in the refrigerator.
Extract the phage buffer from each plaque.
Filter each and, once again, place it in the refrigerator.
High Titer Assay
Determine which was the dilution the completely lysed the bacteria.
Add 10µl of dilution to solution of agar and bacteria.
Distribute the mixture on 10 plates and incubate.
Add phage buffer to all of the plates. Break apart the agar and mix with the buffer.
Place the plates in the incubator, shaking for 4 hours.
Extract the phage buffer, centrifuge, and filter.
Rapid Isolation, Separation and Visualization of Caspid Proteins
Medium: phage buffer extracted from web pattern in MTA
1ml of HTPL to a microtube and centrifuge for an hour.
Aspirate the supernatant.
Prepare sample buffer.
Boil the samples for two minutes and cool them down for two minutes. Centrifuge.
Prepare the gel.
Prepare 1x running buffer.
Carefully handle the gel and assemble it. Add the running buffer.
Cont. SDS Gel
Load samples and molecular weight markers.
Run gel for 30 minutes.
Strain the gel in a plastic tray.
Wash the gel three times.
Stain the gel for one hour with gentle shaking.
Rinse the gel for 30 minutes.
Photograph on white light box.
Store in water in a zip lock bag.
Results: Location
Gurabo, PR. 18°14'48.53"N 66° 0'6.55"W
Sunny/clear morning. 25.6°C. Next to trees and compost.
Dry soil and taken 5.74 inches deep.
Results: Harvesting and Plaque Purifications
Results: Web Pattern
#1 -3 #2 -4
#3 -4
SDS Gel
AS1 is named Shockage and we can see its protein bands.
AS2 and 3 are the same phage based on their protein band similarity and it is named Zombage.
Electron Micrograph Images Difference in abundance and sizes.
Shockage Zombage
Conclusion
Mycobacteriophages are viruses that infect bacteria and have applications in the field of biomedicine.
Two different phages were isolated: Shockage and Zombage.
These phages were taken up to the High Titer Assay Protocol and the SDS gel.
The next step would include to sequence their DNA.
Acknowledgement
Lab Technician: Giovanni Cruz
Christopher Quintanal
Dr. Michael Rubin
RISE Program
Questions?