Community phylogenetic analysis of moderately thermophilic cyanobacterial mats from China, the Philippines and Thailand

Abstract

Most community molecular studies of thermophilic cyanobacterial mats to date have focused on Synechococcus occurring at temperatures of approximately 50-65 degrees C. These reveal that molecular diversity exceeds that indicated by morphology, and that phylogeographic lineages exist. The moderately thermophilic and generally filamentous cyanobacterial mat communities occurring at lower temperatures have not previously been investigated at the community molecular level. Here we report community diversity in mats of 42-53 degrees C recovered from previously unstudied geothermal locations. Separation of 16S rRNA gene-defined genotypes from community DNA was achieved by DGGE. Genotypic diversity was greater than morphotype diversity in all mats sampled, although genotypes generally corresponded to observed morphotypes. Thirty-six sequences were recovered from DGGE bands. Phylogenetic analyses revealed these to form novel thermophilic lineages distinct from their mesophilic counterparts, within Calothrix, Cyanothece, Fischerella, Phormidium, Pleurocapsa, Oscillatoria and Synechococcus. Where filamentous cyanobacterial sequences belonging to the same genus were recovered from the same site, these were generally closely affiliated. Location-specific sequences were observed for some genotypes recovered from geochemically similar yet spatially separated sites, thus providing evidence for phylogeographic lineages that evolve in isolation. Other genotypes were more closely affiliated to geographically remote counterparts from similar habitats suggesting that adaptation to certain niches is also important.

Pigment profiles and bacterial communities from Thailand thermal mats

“…Cyanobacteria are the most commonly reported microbial group constituting these mats and they are considered the major primary producers in these habitats (Castenholtz 1973). Synechococcus-like representatives are the Cyanobacteria usually found at the highest temperatures (up to 74°C; Hongmei et al 2005;Ward and Castenholz 2000). Other bacteria share these environments with the Cyanobacteria and have important roles within these microbial communities (Moyer et al 1995;Ward et al 1990;Weller et al 1992).…”

Isolation and Characterization of Bacteria with Biochemical and Pharmacological Importance from Soil Samples of Dhaka City

“…1 Microorganisms can live in environment along with human and in extreme conditions such hot springs, miles deep in the ocean, inside rocks and in extreme cold temperature. 2 Although the number of microorganisms varies in different places, it has been indicated that mass of carbon from these microorganisms could be trillions of tons. [3][4][5] Correspondence to: Kohinur Begum E-mail: prof.kohinur@asaub.edu.bd/kohinur025@yahoo.com Dhaka Univ.…”

Genetic and morphological characterization of Rivularia and Calothrix (Nostocales, Cyanobacteria) from running water

“…Recently, great sequence variability of the 16S rRNA gene has been found among Calothrix strains from the Baltic Sea (Sihvonen et al, 2007), suggesting that they belong to at least five different genera. Hongmei et al (2005) showed that a single morphotype of Calothrix in thermophilic cyanobacterial mats comprised five different 16S rRNA genotypes. The tree topology obtained from phylogenetic analysis of cyanobacterial 16S rRNA gene sequences in our study was in agreement with that of Sihvonen et al (2007) and supported the idea that members of the genus Calothrix are polyphyletic and should be divided into several different genera.…”