Research:
Visual perception by the mammalian retina is a unique process that requires capturing and converting environmental light stimuli into chemical signals for processing and perception by the brain. The challenges of color discrimination, high sensitivity, high speeds of visual processing and perception, and the need to maintain visual function throughout the lifetime of an animal poses significant metabolic and functional challenges. Retina consumes more oxygen, and has the highest energy demand of all tissues in the body, indicating that unique metabolic strategies may be required for retinal function. I attempt to use tools and concepts in biochemistry, cellular physiology, biophysics, pharmacology & toxicology to articulate the unique metabolic strategies that underlie mammalian visual processes.
Peer-Reviewed Publications (Most current to least current):
1. Chaney, S,; Mukherjee, S.; Giddabasappa, A.; Rueda, E.; Hamilton, W.R.; Johnson, J.E.; Fox, D.A. (2016) Increased proliferation of late-born progenitor cells by gestational lead exposure delays rod and bipolar cell differentiation. Molecular Vision 22: 1468 – 1489.
2. Rueda, E.; Johnson, J.E.; Giddabasappa, A.; Swaroop, A.; Brooks, M.; Sigel, I.; Chaney, S.; Fox, D.A. (2016) The cellular and compartmental profile of mouse retinal glycolysis, tricarboxylic acid cycle, oxidative phosphorylation and P transferring kinases. Molecular Vision 22: 847 – 885.
3. Ahmedli, N.B.; Gribanova, Y.; Mendoza, E.; Collins, C.N.; Yamashita, C.K.; Ozgul, R.K.; Johnson, J.E.; Fox, D.A.; Farber, D.B. (2013) Dynamics of the novel intramembrane Golgi associated rhomboid-like protein, 7R expression in mouse retina. J.Biol.Chem. 288:9742 – 9754.
4. Perkins, G.A.; Scott, R.; Perez, A.; Ellisman, M.H.; Johnson, J.E.; Fox, D.A. (2012) Bcl-xL-mediated remodeling of rod and cone synaptic mitochondria after postnatal lead exposure: electron microscopy, tomography and oxygen consumption. Molecular Vision 18: 3029 – 3048.
5. Fox, D.A.' Hamilton, W.R.; Johnson, J.E.; Xiao, W.; Chaney, S.; Mukherjee, S.; Miller, D.B.; O'Callaghan, J.P. (2011) Gestational lead exposure selectively decreases retinal dopamine amacrine cells and dopamine content in adult mice. Toxicology and Applied Pharmacology, Vol 256. 258 – 267.
6. Giddabasappa, A.C.S.; Hamilton, W.R.; Chaney, S.; Xiao, W.; Johnson. J.E. Jr.; Mukherjee, S.; Fox, D.A. (2010) Low-level gestational lead exposure increases retinal progenitor cell proliferation and rod photoreceptor and bipolar cell neurogenesis in mice. Environmental Health Perspectives. Vol. 119. 71 – 77.
7. Fox, D.A.; Kala, S.V.; Hamilton, W.R.; Johnson, J.E.; O'Callaghan, J.P. (2008) Low-level human equivalent gestational lead exposure produces supernormal scotopic electroretinograms, increased retinal neurogenesis and decreased retinal dopamine utilization in rats. Environmental Health Perspectives, Vol. 116. 618 – 625.
8. Leasure, J. L.; Giddabasappa, A.C.S.; Chaney, S.; Johnson, J.E. Jr.; Pothakos, K.; Lau, Y.S.; Fox, D.A. (2008) Low-level human equivalent gestational lead exposure produces gender-specific motor and coordination abnormalities and late-onset obesity in year-old mice. Environmental Health Perspectives, Vol. 116. 355 – 361.
9. Johnson, J.E. Jr.; Perkins, G.A.; Giddabasappa, A.C.S.; Chaney, S.; Xiao, W.; White, A.D.; Brown, J.M.; Waggoner, J.; Ellisman, M.H.; Fox, D.A. (2007) Spatiotemporal regulation of ATP and Ca2+ dynamics in vertebrate photoreceptor ribbon synapses. Molecular Vision, Vol. 13. 887 – 919.
10. Ohnishi, T.; Johnson, J.E.; Yano, T.; LoBrutto, R.; Widger, W. (2005) Thermodynamic and EPR studies of slowly relaxing SQ species in the isolated bovine heart complex I. FEBS Letters, Vol. 579. 500–506.
11. Johnson, J.E.; Choksi, K.; Widger, W.R. (2003) NADH-ubiquinone oxidoreductase: substrate-dependent oxygen turnover to superoxide anion as a function of flavin mononucleotide. Mitochondrion, Vol. 3. Issue 2. 97–110.
12. Xu, Yi; Johnson, J.E.; Khon, H.; Widger, W.R. (2003) ATP binding to rho transcription termination factor: Mutant F355W ATP-induced fluorescence quenching reveals dynamic ATP binding. Journal of Biological Chemistry, Vol. 278. 13719–13727.
Peer-Reviewed Publications (Most current to least current)
1. Chaney, S,; Mukherjee, S.; Giddabasappa, A.; Rueda, E.; Hamilton, W.R.; Johnson, J.E.; Fox, D.A. (2016) Increased proliferation of late-born progenitor cells by gestational lead exposure delays rod and bipolar cell differentiation. Molecular Vision 22: 1468 – 1489.
2. Rueda, E.; Johnson, J.E.; Giddabasappa, A.; Swaroop, A.; Brooks, M.; Sigel, I.; Chaney, S.; Fox, D.A. (2016) The cellular and compartmental profile of mouse retinal glycolysis, tricarboxylic acid cycle, oxidative phosphorylation and P transferring kinases. Molecular Vision 22: 847 – 885.
3. Ahmedli, N.B.; Gribanova, Y.; Mendoza, E.; Collins, C.N.; Yamashita, C.K.; Ozgul, R.K.; Johnson, J.E.; Fox, D.A.; Farber, D.B. (2013) Dynamics of the novel intramembrane Golgi associated rhomboid-like protein, 7R expression in mouse retina. J.Biol.Chem. 288:9742 – 9754.
4. Perkins, G.A.; Scott, R.; Perez, A.; Ellisman, M.H.; Johnson, J.E.; Fox, D.A. (2012) Bcl-xL-mediated remodeling of rod and cone synaptic mitochondria after postnatal lead exposure: electron microscopy, tomography and oxygen consumption. Molecular Vision 18: 3029 – 3048.
5. Fox, D.A.' Hamilton, W.R.; Johnson, J.E.; Xiao, W.; Chaney, S.; Mukherjee, S.; Miller, D.B.; O'Callaghan, J.P. (2011) Gestational lead exposure selectively decreases retinal dopamine amacrine cells and dopamine content in adult mice. Toxicology and Applied Pharmacology, Vol 256. 258 – 267.
6. Giddabasappa, A.C.S.; Hamilton, W.R.; Chaney, S.; Xiao, W.; Johnson. J.E. Jr.; Mukherjee, S.; Fox, D.A. (2010) Low-level gestational lead exposure increases retinal progenitor cell proliferation and rod photoreceptor and bipolar cell neurogenesis in mice. Environmental Health Perspectives. Vol. 119. 71 – 77.
7. Fox, D.A.; Kala, S.V.; Hamilton, W.R.; Johnson, J.E.; O'Callaghan, J.P. (2008) Low-level human equivalent gestational lead exposure produces supernormal scotopic electroretinograms, increased retinal neurogenesis and decreased retinal dopamine utilization in rats. Environmental Health Perspectives, Vol. 116. 618 – 625.
8. Leasure, J. L.; Giddabasappa, A.C.S.; Chaney, S.; Johnson, J.E. Jr.; Pothakos, K.; Lau, Y.S.; Fox, D.A. (2008) Low-level human equivalent gestational lead exposure produces gender-specific motor and coordination abnormalities and late-onset obesity in year-old mice. Environmental Health Perspectives, Vol. 116. 355 – 361.
9. Johnson, J.E. Jr.; Perkins, G.A.; Giddabasappa, A.C.S.; Chaney, S.; Xiao, W.; White, A.D.; Brown, J.M.; Waggoner, J.; Ellisman, M.H.; Fox, D.A. (2007) Spatiotemporal regulation of ATP and Ca2+ dynamics in vertebrate photoreceptor ribbon synapses. Molecular Vision, Vol. 13. 887 – 919.
10. Ohnishi, T.; Johnson, J.E.; Yano, T.; LoBrutto, R.; Widger, W. (2005) Thermodynamic and EPR studies of slowly relaxing SQ species in the isolated bovine heart complex I. FEBS Letters, Vol. 579. 500–506.
11. Johnson, J.E.; Choksi, K.; Widger, W.R. (2003) NADH-ubiquinone oxidoreductase: substrate-dependent oxygen turnover to superoxide anion as a function of flavin mononucleotide. Mitochondrion, Vol. 3. Issue 2. 97–110.
12. Xu, Yi; Johnson, J.E.; Khon, H.; Widger, W.R. (2003) ATP binding to rho transcription termination factor: Mutant F355W ATP-induced fluorescence quenching reveals dynamic ATP binding. Journal of Biological Chemistry, Vol. 278. 13719–13727.
Awards:
1. University of Houston– Downtown: Excellence in Teaching Award Winner; 2013 – 2014
2. University of Houston– Downtown: Excellence in Service Award Finalist; 2013 – 2014
3. Honorable Mention for the Carl C. Smith Graduate Student Award, Mechanisms Section for the Society of Toxicology annual Meeting in Baltimore, MD; March 2004.