can tetracycline resistance be induced in pseudomonas fluorescens after 3 weeks?
DESCRIPTION
Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?. David S. Abuín & Tania Bembridge Department of Microbiology North Carolina State University. Inspirations. Dr. Richard Lenski of Michigan State University - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/1.jpg)
Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?
David S. Abuín & Tania BembridgeDepartment of Microbiology
North Carolina State University
![Page 2: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/2.jpg)
Inspirations
Dr. Richard Lenski of Michigan State University • E. coli Long-term
Experimental Evolution experiment reaching 50,000 generations
The rise of multiple drug resistant organisms.
![Page 3: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/3.jpg)
‒ an environmental bacteria that inhabits soil, water and plant surfaces.
‒ beneficial for plants by ‒ inhibiting pathogens‒ aiding nutrient absorption‒ degrading environmental
pollutants.
‒ Gram negative
Pseudomonas fluorescens
![Page 4: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/4.jpg)
Tetracycline is broad spectrum antibiotic
• Tetracycline antibiotics are protein synthesis inhibitors• They prevent the binding of tRNA to the mRNA-ribosome
complex. • They bind to the 30S ribosomal subunit in the mRNA
translation complex• Tetracycline inhibits cell growth by inhibiting translation.
It can be inactivated by bivalent ions.
![Page 5: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/5.jpg)
The Method.
0:00:00 12:00:00 24:00:00 36:00:00 48:00:00 60:00:00 72:00:000.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.10 mM (11-7)
0.20 mM (11-7)
0.10 to 0.31 mM (11-7)
0.20 to 0.31 mM (11-7)
0.20 to 0.42 mM (11-7)
0.42 mM (11-7)
Time
OD
0.10
0.10- > 0.31
0.20
0.20 -> 0.31
0.20 -> 0.42
0.42
Concentration Push0.10 - Blue0.10 to 0.31 – Aqua
0.20 - Red0.20 to 0.31 – Dark red0.20 to 0.42 - Pink
![Page 6: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/6.jpg)
Tetracycline resistance at 0.20 mM concentration
0:00:00 12:00:00 24:00:00 36:00:00 48:00:00 60:00:00 72:00:000.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.20 mM (11-7)
0.20 mM (10-31)
0.20 mM (10-24)
Axis Title
OD
0.20 mM Tetra-cycline
1st trial(Oct 24)
2nd trial(Oct 31)
3rd trial(Nov 7)
Time
![Page 7: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/7.jpg)
Tetracycline resistance at 0.42 mM concentration
![Page 8: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/8.jpg)
Resistance Genes
Encodes a membrane protein that actively pumps tetracycline out of the cell
Pseudomonas tet(A) (B) (C) (E) (G) (M) (34) (L) (X) (42)h
Encodes proteins that protect the ribsomes
![Page 9: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/9.jpg)
Conclusion• Data is inconsistent to definitively demonstrate
directed evolution had occurred.
• Possible contamination due to continuous shaking in the Bioscreen C detector as well as during transfer process.
• Contamination of each trial of LB only media
![Page 10: Can Tetracycline resistance be induced in Pseudomonas fluorescens after 3 weeks?](https://reader036.vdocuments.us/reader036/viewer/2022062305/568163ef550346895dd5667c/html5/thumbnails/10.jpg)
Further Direction
• Test hypothesis with an anaerobic organism to limit possible contamination.
• Determine the pathways which antibiotics use to destroy microorganisms and how the coping mechanisms that survivors use.
• Is there a much faster way to induce directed mutation in favor of antibiotic resistance?