Investigação de fatores ambientais como indutores de luminescência em bactérias do gênero vibrio

Abstract

Among bioluminescent marine microorganisms, bacteria from genus Vibrio such as Vibrio harveyi and Vibrio cholerae has luminescent capabilities associated with the pathogenicity that causes disease in aquacultured organisms in several countries. Also the genus Aliivibrio figure with species of ecological importance, particularly Aliivibrio fischeri and Aliivibrio logei. Nevertheless, the bioluminescence ability is still poorly understood and not yet clear which environmental conditions or inhibitory activity. The aim of this study was to evaluate the influence of abiotic factors on the bioluminescence of marine bacteria isolated from hemolymph of marine shrimp species Litopenaeus vannamei, from water from experimental cultivation tank of marine shrimp and from water of Cocó and Pacoti estuaries. Initially, strains were submited to initial tests to restrict the isolation only to those already known as bioluminescent and then were subjected to tests simulating different values of abiotic parameters tested. Tests were also carried out to observe the influence of the quorum-sensing phenomenon, to observe the ability to induce luminescence among different species of bacteria. We observed that, with the exception of temperature, the values that most stimulated bioluminescence were similar to those found in the natural environment of occurrence of bacteria. The quorum-sensing does not seem to influence the inter-specific luminescence and the tests of abiotic factors. Since bacterial communities are reflective of local conditions, specific studies are necessary for understanding the distribution and identification.