Prokaryotic diversity and the importance of culturing

Modern approaches based on the use of molecular techniques presumed to circumvent the need for culturing prokaryotes, fail to provide sufficient and reliable information for estimation of prokaryote diversity. Many properties that make these organisms important members of the living world are amenable to observation only through the study of living cultures. Since current culture techniques do not always satisfy the need of providing a balanced picture of the microflora composition, future developments in the study of bacterial diversity should include improvements in the culture methods to approach as closely as possible the conditions of natural habitats. Molecular methods of microflora analysis have an important role as guides for the isolation and characterization of new prokaryotic taxa. Although the species concept is central to biodiversity studies, it is extremely difficult to propose a definition applicable without constraints to all groups of living organisms. However, in prokaryote systematics much improvement has been achieved by comprehensive descriptions that include not only molecular data, but also the relevant aspects of the biology of the organisms under study (polyphasic approach).