Kenneth H. Johnston, PhD

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	Kenneth H. Johnston, PhD Professor, Microbiology, Immunology and Parasitology MIP Department 1901 Perdido Street, Box P6-1 New Orleans, LA 70112 Phone: (504) 568-8093 Fax: (504) 568-2918 khjohns@lsuhsc.edu
Bio	The Johnston laboratory is interested in the pathogenesis of streptococcal infections with particular emphasis on the role of certain isotypes of streptokinase which may be the initiating factor in post-streptococcal glomerulonephritis. Recently, this laboratory has demonstrated the species-specificity of plasminogen activation and currently is involved in determining what are the specific binding and activation domains of the streptokinase-plasminogen interaction that are the determinants of this species specificity. This involves the combined use of molecular biology to construct molecular chimeras and X-ray crystallography. In collaboration with Dr. Pelon, this laboratory is studying the chemistry and action of the anti-Vibrio vulnificus oyster defensin (AVVOD) which is produced by a number of molluscs and which appears to specifically exert its anti-microbial activity against the VBNC state of V. vulnificus. As it appears that AVVOD may act upon the VBNC state of V. vulnificus, the biology of this state and its potential role in human pathogenesis is of great interest. Other areas of investigation involve the use of Matrix-Assisted Laser Desorption/Ionization Time-Of Flight (MALDI-TOF) spectrophotometric analysis to identify proteins unique to microorganisms that cannot be cultivated or are difficult to cultivate in the laboratory. This area is being expanded to identify microbial flora, particularly anaerobic flora, which are involved in dental disease by the combined use of 16s RNA genomic analysis and MALDI-TOF analysis to permit rapid identification of resident flora.
Research Interests	Bacterial plasminogen activators as initiators of on disease Oyster defensins with particular emphasis on their role in the modulation of bacterial infections Vibrio species, proteonomic analyses of
Selected Publications	Miles, DH, Johnston, KH, and Freistadt, MS, An improved method for detection and quantification of differential interactions between poliovirus internal ribosome entry site RNA and pyrimidine tract binding protein from primary cells, J Virol Methods 96:67-84, 2001. Haag, AM, Chaiban, J, Johnston, KH, and Cole, RB, Monotoring of immune response by blood serum profiling using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, J Mass Spectrom 36:15-20, 2001. Haag, AM, Taylor, SN, Johnston, KH, and Cole, RB, Rapid identification of Haemophilus and other bacteria by matrix-assisted laser desorption/ionization time-of flight mass spectrometry, Am Clin Lab 19:20-21, 2000. Caballero, AR, Lottenberg, R, and Johnston, K.H, Cloning, expression, sequence analysis, and characterization of streptokinases secreted by porcine and equine isolates of Streptococcus equisimilis, Infect Immun 67:6478-6486, 1999.
Additional Info	Publications at PubMed

Professor, Microbiology, Immunology and Parasitology