tailieunhanh - Phospholipases C from Pseudomonas aeruginosa and Bacillus cereus isolates, chromosome-mediated enzymes with roles in virulence

Phospholipases C (PLCs) from Pseudomonas aeruginosa D183 and Bacillus cereus D101, 2 clinical isolates from 2 pus specimens, were partially purified by ammonium sulfate precipitation followed by dialysis and used to study the possible role of PLC in the virulence of the isolates. | Turkish Journal of Biology Research Article Turk J Biol (2013) 37: 433-442 © TÜBİTAK doi: Phospholipases C from Pseudomonas aeruginosa and Bacillus cereus isolates, chromosome-mediated enzymes with roles in virulence Nooran ELLEBOUDY, Mohammad ABOULWAFA*, Nadia HASSOUNA Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt Received: Accepted: Published Online: Printed: Abstract: Phospholipases C (PLCs) from Pseudomonas aeruginosa D183 and Bacillus cereus D101, 2 clinical isolates from 2 pus specimens, were partially purified by ammonium sulfate precipitation followed by dialysis and used to study the possible role of PLC in the virulence of the isolates. Partially purified PLC from both isolates induced lysis of Vero cells in the presence and absence of the producing bacterial cells. Noncytolytic dilutions of the partially purified PLC from Pseudomonas aeruginosa increased adherence of the producing cells to Vero cells but did not affect internalization. However, Bacillus cereus cells neither adhered to nor were internalized within the Vero cells in the presence or absence of noncytolytic dilutions of partially purified PLC from the isolate. Both PLC preparations were hemolytic to human red blood cells but did not induce human platelet aggregation. Thus, we can conclude that PLCs from Pseudomonas aeruginosa and Bacillus cereus are important virulence factors. PLC production by the 2 isolates was found to be chromosomal-mediated rather than plasmid-mediated. Key words: Phospholipase C, Pseudomonas aeruginosa, Bacillus cereus, catalytic activity 1. Introduction Phospholipases C (PLCs) have a special place in the history of bacterial toxinology because the α-toxin (PLC) of Clostridium perfringens was the first bacterial toxin shown to have an enzymatic mode of action (1). Bacterial PLCs comprise a diverse group of