Microbial diversity associated with algae, ascidians and sponges from the north coast of Sao Paulo state, Brazil

Little is known about the microbial diversity associated with marine macroorganisms, despite the vital role microorganisms may play in marine ecosystems. The aim of the present study was to investigate the diversity of bacteria and fungi isolated from eight marine invertebrate and one algae samples. Data derived from ARDRA and sequencing analyses allowed the identification of marine-derived microorganisms isolated from those samples. Microbial strains identified up to the genus level revealed 144 distinct ribotypes out of 256 fungal strains and 158 distinct ribotypes out of 181 bacterial strains. Filamentous fungi were distributed among 24 different genera belonging to Ascomycota, Zygomycota and Basidiomycota, some of which had never been reported in the literature as marine invertebrate-inhabiting fungi (Pestalotiopsis, Xylaria, Botrysphaeria and Cunnninghamella). Bacterial isolates were affiliated to 41 different genera, being Bacillus, Ruegeria, Micrococcus, Pseudovibrio and Staphylococcus the most abundant ones. Results revealed an unexpected high microbial diversity associated to the macroorganisms which have been collected and suggested the selection of certain microbial taxonomic groups according to the host. The combined data gathered from this investigation contribute to broaden the knowledge of microbial diversity associated to marine macroorganisms, including as a promising source for the discovery of new natural products. (C) 2009 Elsevier GmbH. All rights reserved.

Diversity and quantitative analysis of Archaea in aggressive periodontitis and periodontally healthy subjects

P>Aim To investigate the diversity, levels and proportions of Archaea in the subgingival biofilm of generalized aggressive periodontitis (GAgP; n=30) and periodontally healthy (PH; n=30) subjects. Materials and methods Diversity was determined by sequencing archaeal 16S rRNA gene libraries from 20 samples (10/group). The levels and proportions of Archaea were analysed by quantitative PCR (qPCR) in four and two samples/subject in GAgP and PH groups, respectively. Results Archaea were detected in 27/28 subjects and 68% of the sites of the GAgP group, and in 26/30 subjects and 58.3% sites of the PH group. Methanobrevibacter oralis was found in all 20 samples studied, Methanobacterium curvum/congolense in three GAgP and six PH samples, and Methanosarcina mazeii in four samples from each group. The levels and proportions of Archaea were higher in GAgP than in PH, whereas no differences were observed between the two probing depth category sites from the GAgP group. Conclusion Archaea were frequently found in subjects with periodontal health and GAgP, especially M. oralis. However, the higher levels and proportions (Archaea/total prokaryotes) of this domain observed in GAgP in comparison with PH subjects indicate a possible role of some of these microorganisms as an environmental modifier in GAgP.

Exploring Bacterial Diversity of Endodontic Microbiota by Cloning and Sequencing 16S rRNA

Introduction: The characterization of microbial communities infecting the endodontic system in each clinical condition may help on the establishment of a correct prognosis and distinct strategies of treatment. The purpose of this study was to determine the bacterial diversity in primary endodontic infections by 16S ribosomal-RNA (rRNA) sequence analysis. Methods: Samples from root canals of untreated asymptomatic teeth (n = 12) exhibiting periapical lesions were obtained, 165 rRNA bacterial genomic libraries were constructed and sequenced, and bacterial diversity was estimated. Results: A total of 489 clones were analyzed (mean, 40.7 +/- 8.0 clones per sample). Seventy phylotypes were identified of which six were novel phylotypes belonging to the family Ruminococcaceae. The mean number of taxa per canal was 10.0, ranging from 3 to 21 per sample; 65.7% of the cloned sequences represented phylotypes for which no cultivated isolates have been reported. The most prevalent taxa were Atopobium rimae (50.0%), Dialister invisus, Pre-votella oris, Pseudoramibacter alactolyticus, and Tannerella forsythia (33.3%). Conclusions: Although several key species predominate in endodontic samples of asymptomatic cases with periapical lesions, the primary endodontic infection is characterized by a wide bacterial diversity, which is mostly represented by members of the phylum Firmicutes belonging to the class Clostridia followed by the phylum Bacteroidetes. (J Ended 2011;37:922-926)