Lectura - 23 Septiembre de 2014

Omic Approaches in Microbial Ecology: Charting the Unknown 

Analysis of whole-community sequence data is unveiling the diversity and function of specific microbial groups within uncultured phyla and across entire microbial ecosystems

Brett J. Baker and Gregory J. Dick

Nearly a decade ago, Jill Banfıeld of the University of California, Berkeley, and her collaborators applied random shotgun DNA sequencing to microbial biofılms from extremely acidic waters in the Iron Mountain mine in California, assembling genomes for the most abundant of those microbes. Although they relied on Sanger sequencing, whose yields are modest compared to other DNA-sequencing techniques that are now available, their efforts showed that genome sequences could be reconstructed directly from environmental samples, bypassing cultivation while providing insights into the uncultured members of that microbial community.

Lectura 2 - 9 Septiembre 2014

Insights into the phylogeny and coding potential of microbial dark matter

Christian Rinke, Patrick Schwientek, Alexander Sczyrba, et al.

Microorganisms are themost diverse and abundant cellular life forms on Earth, occupying every possible metabolic niche. The large majority of these organisms have not been obtained in pure culture and we have only recently become aware of their presence mainly through cultivation-independent molecular surveys based on conservedmarker genes (chiefly small subunit ribosomal RNA; SSU rRNA) or through shotgun sequencing (metagenomics). As an increasing number of environments are deeply sequenced using next-generation technologies, diversity estimates for Bacteria and Archaea continue to rise, with the number of microbial ‘species’ predicted to reach well into the millions.

Lectura 1 - 9 Septiembre 2014

Bypassing Cultivation To Identify Bacterial Species

Culture-independent genomic approaches identify credibly distinct clusters,avoid cultivation bias, and provide true insights into microbial species

Luis M. Rodriguez-R and Konstantinos T. Konstantinidis

Whether bacterial species exist as a natural unit remains an unresolved issue, one with important practical challenges, including that of correctly identifying microorganisms and diagnosing the causative agents of microbial diseases. The current bacterial species defınition is based on genetic and phenotypic distinctiveness of organisms grouped under the same name.