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Does the rate of inhibition of Tetracycline change in different pH environments?. Daniel Bj ö rkman , Caleb Wilson. Background. Purpose of Question Will it still be effective in biological systems with Different pHs ? Abnormal region of infection? Introduced endogenous pathogen
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Does the rate of inhibition of Tetracycline change in different pH environments? Daniel Björkman, Caleb Wilson
Background • Purpose of Question • Will it still be effective in biological systems with • Different pHs? • Abnormal region of infection? • Introduced endogenous pathogen • Bacteria Resistant Mechanisms? • Variables in Question • Best E.colipH for maximum growth • Optimal [TET] for experiment
Definition of Variables • pH chosen = 6.0 • E.coliaround 7.0 • Stock NB around pH 6.5
[TET] Optimization 0.32x, taken down from 1000x [2]. Measurable amount of inhibition without effects from ethanol.
Results Figure 1 Results from biological replicates in triplicate test pHs 4, 5, 7 ,8, 9, and 10 at [0.32x] TET with E.coli.
Reference Series Used to determine a normal rate of inhibition of [0.32x] TET , defined at pH 6.5
Ionization States of Tetracycline Mechanism of Uptake? Does this relate to our data? Conclusions This IS a change in the effectiveness of TET in different pHs. Protonated form most easily passes through cell membrane [3]. Effects of ethanol on E.coligrowth? [3]
References • [1] Yamaguchi, A., Ohmori, H., Kaneko-Ohdera, M., Nomura, T., & Sawai, T. (1991). Δph-dependent accumulation of teracycline in ischerichia coli. Antimicrobial Agents and Chemotherapy, 35(1), 53-56. • [2] Sanders, C. R. (2011). Sanders lab protocol. Retrieved from <http://structbio.vanderbilt.edu/sanders/ dgk_protocols.pdf> • [3] Jin, L., Amaya-Mazo, X., Apel, M. E., Sandisa, S. S., Johnson, E., Zbyszynska, M. A., & Han, A. (2007). Ca2 and mg2 bind tetracycline with distinct stoichiometries and linked deprotonation. BiochysicalChemisry, 128(2-3), 185-96. doi: 10.1016/j.bpc.2007.04.005 • [4]Delcour, A. H. (2009). Outer membrane permeability and antibiotic resistance. BBA: Proteins and Proteomics, 1794(5), 808-16. doi: 10.1016/j.bbapap.2008.11.005