Cytogenetic assays of the mutagenic potential of the bacterium, Pseudomonas aeruginosa in five species of experimentally treated fish

Abstract

Various species of the bacteria including Pseudomonas aeruginosa have been recognized as pathogens of fish. The mutagenic potential of P. aeruginosa log culture (17×10⁷ cells/ml) has been assessed after intraperitoneal injection at 1 ml per 100 g b. w. to cichlid mouth brooding fresh water tilapia, O. mossambicus by chromosome aberrations in gill epithelia and first spermatocyte metaphase, micronucleus test (MNT) in peripheral blood, gill epithelia and kidney cells, and lethal test for unfertilized eggs and dead embryos during development after mating treated male parents with normal virgin females. Moreover, dose dependent effect of ½ ml, 1 ml and 2 ml doses for chromosome aberrations in gill epithelia and MNT in cells of blood, gill and kidney were found to be highly positive against respective sterile peptone medium injected controls. The sperm head abnormality test yielded no positive result. Further, the intraperitoneal injection of log culture of P. aeruginosa of 1 ml dose to Indian climbing perch, A. testudineus yielded positive results in chromosome aberrations studied from kidney and gill epithelia and MNT in cells of blood, gill and kidney. The three species of Indian major carps, L. rohita, C. catla and C. mrigala also yielded positive genotoxic potential of P. aeruginosa by MNT. There was intraspecific tissue sensitivity among blood, gill and kidney cells found in MNT of O. mossambicus and interspecific sensitivity shown by MNT of blood of three species of Indian major carps. The mutagenic potential of P. aeruginosa evaluated by a battery of tests in directly treated and in F₁ and F₂ generations of experimental mouse recorded before revealed that P. aeruginosa can act as a potential mutagen to fish in aquatic media and to mice in terrestrial one. Thus 'Microbes as living Mutagens' advocated by Manna (1980, 1989) has been supported from the present result on fish.