The round table discussion on taxonomy and biodiversity, organized by Prof. Brian Austin (University of Stirling, UK), Dr. Rita Colwell (University of Maryland, College Park, USA) and Prof. Fabiano Thompson [Federal University of Rio de Janeiro, Brazil), was designed to be thought-provoking, and to stimulate discussion. The value of laboratory cultures and their relevance to fresh cultures was questioned, given the often a rapid loss of biological activity in the laboratory and the consequent differences between cultures from long-term storage and fresh isolates. In particular, the relevance of culturing might be questioned insofar as it is accepted that not all cells grow on laboratory media. Indeed, the culturable proportion of any cell population might be quite limited. This raises the question of how many new and as yet un-described Vibrio spp. might be unable to grow on laboratory media. Thus, culture-independent molecular approaches are crucial, although it is important to correct errors in the databases that are used for comparison. However, criticism may be levelled at the current approach of describing new taxa based on the study of only single cultures without evaluating the variability within a species. The study of multiple isolates of any given taxon should be encouraged. Nevertheless, taxonomy has moved forward with the adoption of many modern methods that increase the reliability of the data, and enable sound conclusions to be reached. The fascinating question of the homogeneity of cells within single colonies was also raised in view of the fact that modern approaches allow individual cells to be examined in detail. Indeed, phenotypic variability has been noted in individual cells, leading to the possibility that some genes may only be expressed in certain cells to save energy for the population as a whole.
Phenotypic characterization is mandatory in the description of new taxa. The presentation by Dr. Ana P. Moreira (Federal University of Rio de Janeiro, Brazil), on the new approaches to prokaryotic (vibrio) taxonomy suggested that phenotypes can be predicted directly from genome sequences [19] and [20]. According to this speaker, the analysis of genome sequences is enough to define the diagnostic phenotype of new taxa.