Description of prokaryotic biodiversity along the salinity gradient of a multipond solar saltern by direct PCR amplification of 16S rDNA

摘要: New methods based on PCR amplification of 16S rRNA genes from DNA samples extracted directly the environment allow description microbial diversity in natural ecosystems without need for cultivation. We have applied this technique to an extreme presumed very low diversity: crystallizer ponds a marine saltern with salinity over NaCl saturation. The molecular methodology has shown that indeed can be found here. Prokaryotes belonging Bacteria domain are minor component and only members closely related cluster sequences were found, all relatives α-Proteobacteria (ca. 83% Rhodopseudomonas marina). Halophilic Archaea as expected largest biomass environment. All clones sequenced corresponded again highly homologous (probably same genus). However, diverged considerably ones described genera halophilic Archaea, fact data consistent idea amplified correspond undescribed genus. This is remarkable since many collection strains come specifically saltern. Furthermore, rDNA obtained archaeal cultures isolated sample had no homology by amplification, instead they appear well known genus Haloarcula. concurs findings other authors who different organisms culture those detected retrieved PCR. A possible explanation culturability, standard media, exception rather than rule. To study biodiversity gradient present along multi-pond solar we also novel strategy. method restriction digestion population environmental sample. Digested fragments separated polyacrylamide gel electrophoresis generate characteristic profile estimation overall similarities between environments. been set five covering about twice seawater (6.4%) NaCI precipitation (30.8%). Bacterial (eubacterial) estimated complexity banding pattern amplicons decreased increasing while (archaebacteria) reverse was true i.e. higher number bands. taxonomic composition prokaryotic populations evaluated bands shared samples. relationships among environments independent enzyme used previous descriptions isolates appears promising rapid fingerprinting useful compare several detect major shifts species population.