Enrollment Information
1-800-422-4LLU (1-800-422-4558)
Department of microbiology and molecular genetics
Faculty profile
 |
Barry L. Taylor Vice chancellor for research affairs and professor 24888 Prospect Street |
- PhD, Case Western Reserve University, 1973
- Postdoctoral fellow: University of California at Berkeley; Australian National University
- Current research interests
- Recent publications
* How do cells sense oxygen and energy? Bacteria have the remarkable ability to navigate to the precise concentration of oxygen that is optimal for growth. This behavior is called aerotaxis. My laboratory investigates the signal transduction pathways for aerotaxis in E. coli and other bacteria as model systems for learning how oxygen receptors might function in higher organisms. We have recently identified two oxygen transducers, the Aer and Tsr proteins in E. coli. The Aer protein has a PAS domain that is similar to domains in human oxygen-sensing proteins, such as hypoxia-inducible factor-1. Understanding human responses to hypoxia is of considerable medical importance, and our studies of Aer are suggesting common mechanisms for PAS-domain-containing proteins.
* Structure-function studies of the aerotaxis transducer Aer and PAS domains. We have cloned the aer gene. Using cysteine scanning mutagenesis, we have identified residues in Aer that are important for signal transduction, including residues that transform a positive signal into a negative response. Current projects will determine: the structure of Aer and the role of the critical residues; the role of FAD in signaling by Aer; and the cellular components that interact with Aer. A combination of genetic, molecular biology, and biochemical strategies are utilized in answering these questions. This provides students with a broad exposure to current techniques and allows each to extensively pursue a methodology of choice. By forming chimeras with PAS domains of other oxygen sensing proteins we hope to identify common signal transduction strategies for oxygen receptors.
* Ecological role of bacterial behavior to oxygen. Studies in collaboration with Dr. Igor Zhulin and other investigators are aimed at determining how aerotaxis provides a selective advantage to bacteria in their natural environment. Important findings include evidence that the bacteria migrate to a niche where the cellular energy levels are highest for growth. E. coli does not sense oxygen directly. Instead, Aer and Tsr monitor the energy level of the bacteria. By monitoring their own energy, bacteria can avoid not only hypoxic micro-environments but other environments that do not support maximal energy in the bacteria. The concept of energy-sensing has been proposed previously but the Aer signal transduction pathway now provides a mechanism for energy-sensing behavior.
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Yu, H.S., J. H. Saw, S. Hou, R.W. Larsen, K. Watts, M.S. Johnson, M. Zimmer , G. Ordal, B.L. Taylor, and M. Alam. 2002. Aerotactic Responses in Bacteria to Photoreleased Oxygen. FEMS Microbiol. Lett. 217:237-242.
Yu, H.S., J. Saw, S. Hou, R. W. Larsen, K. J. Watts, M. S. Johnson, M. A. Zimmer, G. W. Ordal, B. L. Taylor, M. Alam. 2002. Aerotactic response in bacteria to photoreleased oxygen. FEMS Microbiology Letters. 217:237-242.
Taylor, BL, A Rebbapragada and MS Johnson. 2001. The FAD-PAS domain as a sensor for behavioral responses in Escherichia coli. Antioxidants and Redox Signaling, 3:867-879.
Repik, A, A Rebbapragada, MS Johnson, JO Haznedar, IB Zhulin and BL Taylor. 2000. PAS domain residues involved in signal transduction by the Aer redox sensor of Escherichia coli, Mol. Microbiol. 36, 806-816.
Alexandre, G., R. Bally, B. L. Taylor and I. B. Zhulin. 1999. Loss of cytochrome c oxidase activity and acquisition of resistance to exogenous quinones in a laccase-positive variant of Azospirillum lipoferum. J. Bacteriol. 181:6730-6738.
Taylor, B. L., I. B. Zhulin and M. S. Johnson. 1999. Aerotaxis and related responses in bacteria. Annu. Rev. Microbiol. 53:103-128.
Taylor, B. L., and I. B. Zhulin. 1999. PAS domains: internal sensors of oxygen, redox potential and light. Microbiol. Mol. Biol. Rev. 63:479-506.
Zhulin, I. B. and B. L. Taylor. 1998. Correlation of PAS domains with electron transport-associated proteins in completely sequenced microbial genomes. Mol. Microbiol. 29:1522-1523.
Taylor, B. L., and I. B. Zhulin. 1998. In search of a higher energy: metabolism-dependent behavioral responses in bacteria. Mol. Microbiol. 28: 683-690.
Taylor BL & MS Johnson (1998). Rewiring a receptor: negative output from positive input. FEBS Letters. 425, 377-381.
Rebbapragada, A, MS Johnson, GP Harding, AJ Zuccarelli, HM Fletcher, IB Zhulin and BL Taylor. 1997. Aer and Tsr transduce oxygen, redox, energy signals for Escherichia coli behavior. Proc. Natl. Acad. Sci. 94, 10541-10546.
Zhulin, IB, BL Taylor and R Dixon. 1997. PAS domain S-boxes in archaea, bacteria and sensors for oxygen and redox. Trends Biochem. Sci. 22, 331-333.
Frankel, RB, DA Bazylinski, MS Johnson and BL Taylor. 1997. Magneto-aerotaxis in marine, coccoid bacteria. Biophys. J. 73, 994-1000.
Johnson, MS, IB Zhulin, MER Gapuzan and BL Taylor. 1997. Oxygen-dependent growth of the obligate anaerobe Desulfovibrio vulgaris Hildenborough. J. Bacteriol. 179, 5598-5601.
Zhulin, IB, EH Rowsell, MS Johnson and BL Taylor. 1997. Glycerol as attractant for chemotaxis of Escherichia coli and Salmonella typhimurium. J. Bacteriol. 179, 3196-3201.
Taylor, BL. 1997. Oxygen transducers that regulate behavior in bacteria. In: Lopez-Borneo, J & Weir, EK. Oxygen Regulation of Ion Channels and Gene Expression. pp. 45-46. Armonk, NY: Futura Publishing Company, Inc.,
Zhulin, IB, MS Johnson and BL Taylor. 1997. How do bacteria avoid high oxygen concentrations? Biosci. Rep. 17, 335-342.
Bespalov, VA, IB Zhulin and BL Taylor. 1996. Behavioral responses of Escherichia coli to changes in redox potential. Proc. Natl. Acad. Sci. USA 93, 10084-10089.
Zhulin, IB, VA Bespalov, MS Johnson and BL Taylor. 1996. Oxygen taxis and proton motive force in Azospirillum brasilense. J. Bacteriol. 178, 5199-5204.
School of Medicine - Graduate School - Loma Linda University
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