Investigation of bacterial diversity in Brazilian tropical estuarine sediments reveals high actinobacterial diversity

Abstract

Phylogenetic and statistical analyses of 16S rRNA gene libraries were used for the investigation of actinobacterial communities present in two tropical estuarine sediments ͑Santos-São Vicente estuary, Brazil͒. The libraries were constructed from samples collected at the brackish end of the estuary, highly hydrocarbon-contaminated, and at the marine end, uncontaminated. Clones from the marine end of the estuary were all related to sequences from non-cultured Actinobacteria and unidentified bacteria recovered from a wide range of environmental samples, whereas clones from the brackish end were mainly related to sequences from cultured Actinobacteria. Statistical analyses showed that the community recovered from the hydrocarbon-contaminated sediment sample, at the brackish end, was less diverse than the uncontaminated one, at the marine end, and that the communities from the two libraries were differently structured, suggesting that these may have not originated from the same community. The recognition of the spatial pattern of actinobacterial distribution in a natural environment is a first step towards understanding the way these communities are organized, providing valuable data for further investigations of their taxonomic and functional diversity.

Microbial Community Diversity Associated with Carbon and Nitrogen Cycling in Permeable Shelf Sediments

“…In corroboration of results from group-specific FISH probes (8,31,54) applied to similar sedimentary environments, we observed abundant phylotypes affiliated with the phylum Proteobacteria (classes Alpha-, Delta-, and Gammaproteobacteria). In addition, phylotypes related to Planctomycetes, Actinobacteria, Acidobacteria, Bacteroidetes/Chlorobi, and Firmicutes, all of which are commonly found in less permeable sediments of the deep sea and estuaries, were detected (2,4,29,32,35,46,65). As is often the case in environmental sequence analysis, the majority of phylotypes we detected were not closely related to any cultivated representatives, and the sequences of several microbial groups were detected which have not been observed in past studies of permeable sands.…”

Screening of bacteria to produce polyhydroxyalkanoates from xylose

“…The primers used for 16S rDNA gene amplification were 27F (Lane 1991) 5 0 AGA GTT TGA TCM TGG CTC AG 3 0 and 1401R (Heuer et al 1997) 5 0 CGG TGT GTA CAA GAC CC 3 0 . Polymerase chain reaction and sequencing procedures are described by Piza et al (2004). The Molecular Evolutionary Genetics Analysis, Version 3.1 (Kumar et al 2004) was used for sequence alignment and phylogram design.…”

Culturable Actinobacteria from the Marine Sponge Hymeniacidon perleve: Isolation and Phylogenetic Diversity by 16S rRNA gene-RFLP Analysis

“…However, little is known about the diversity of actinobacteria from marine samples compared to the diverse range of actinobacteria isolated from terrestrial environments. Increasing numbers of both culture-based studies and culture-independent molecular studies show that many actinobacteria exist in marine environments such as sediments, seawater, and marine invertebrates (Cifuentes et al 2000;Hentschel et al 2001;Mincer et al 2002;Piza et al 2004;Webster et al 2004). A major novel marine actinobacterial taxon in ocean sediments was found to have widespread, persistent populations in ocean systems (Mincer et al 2002) and some taxa have no counterparts in terrestrial environments (Hentschel et al 2001;Montalvo et al 2005;.…”