True marine and halophilic anoxygenic phototrophic bacteria

Authors
Citation
Jf. Imhoff, True marine and halophilic anoxygenic phototrophic bacteria, ARCH MICROB, 176(4), 2001, pp. 243-254
Citations number
53
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
0302-8933 → ACNP
Volume
176
Issue
4
Year of publication
2001
Pages
243 - 254
Database
ISI
SICI code
0302-8933(200110)176:4<243:TMAHAP>2.0.ZU;2-B
Abstract
Anoxygenic phototrophic bacteria are widely distributed in marine sediments and shallow waters of the coastal zone, where they often form intensely co lored mass developments. The phototrophic bacteria have adapted to the whol e spectrum of salt concentrations, from freshwater to saturated brines, and it is apparent that individual species have adapted well to particular hab itats and mineral salts compositions, both qualitatively and quantitatively . This adaptation is reflected not only in the demand for defined ranges of salt concentrations, but also in the phylogenetic relationships of these b acteria, as established by 16S rDNA sequences. Major phylogenetic branches of purple sulfur bacteria are represented by: (1) marine and extremely halo philic Ectothiorhodospiraceae, (2) truly marine and halophilic Chromatiacea e and (3) freshwater Chromatiaceae, some of which are tolerant to low salt concentrations and are successful competitors in brackish and marine habita ts. Quite similarly, salt-dependent green sulfur bacteria form distinct phy logenetic lines. In addition, also among the phototrophic alpha -Proteobact eria (purple nonsulfur bacteria), distinct phylogenetic lines of salt-depen dent species are recognized. Available data give rise to the assumption tha t salt concentrations of natural habitats are an important selective factor that determines the development of a selected range of phototrophic bacter ia in an exclusive way. As a consequence, the salt responses of these bacte ria are reflected in their phylogenetic relationships.