At the desert oasis of Cuatro Ciénegas in Coahuila, México, more than 300 oligotrophic pools can be found and a large number of endemic species of plants and animals. The most divergent taxa of diatoms, snail and fishes are located in the Churince hydrological system, where we analyzed the local diversification of cultivable Firmicutes and Actinobacteria. The Churince hydrological system is surrounded by gypsum dunes and has a strong gradient for salinity, temperature, pH and dissolved oxygen. In August 2003, surface water samples were taken in 10 sites along the Churince system together with the respective environmental measurements. 417 thermo-resistant bacteria were isolated and DNA was extracted to obtain their BOX-PCR fingerprints, revealing 55 different patterns. In order to identify similarities and differences in the diversity of the various sampling sites, an Ordination Analysis was applied using Principal Component Analysis. This analysis showed that conductivity is the environmental factor that explains the distribution of most of the microbial diversity. Phylogenetic reconstruction from their 16S rRNA sequences was performed for a sample of 150 isolates. Only 17 sequences had a 100% match in the Gene Bank (NCBI), representing 10 well known cosmopolitan taxa. The rest of the sequences cluster in 22 clades for Firmicutes and another 22 clades for Actinobacteria, supporting the idea of high diversity and differentiation for this site.
|Original language||English (US)|
|Number of pages||16|
|Journal||Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology|
|State||Published - Feb 2011|
Bibliographical noteFunding Information:
Acknowledgments This research was supported by an UNAM scholarship to RC, as well as grants from SEMARNAT (0237, 23459) and CONACyT SEP (44673 and 57507) to VS and LE. We thank A Escalante, L Espinosa, R González and A Cruz for their helpful opinions, fieldwork and or laboratory support. Special thanks to A Zavala for statistical support, L Falcon and R Salas for thoughtful comments. JS is supported by NASA’s Exobiology program (US), and MT is supported by the NSF (US). LEE and VS worked in this manuscript while in sabbatical at UCI (US) supported by UC-Mexus and DGAPA–UNAM, respectively.
- Bacterial diversity
- Local diversification