Pigment profiles and bacterial communities from Thailand thermal mats

Abstract

Differently colored layers of freshwater hot spring mats at Boekleung (Western Thailand) were studied. Temperatures ranged from over 50 up to 57 degrees C. Two mats were characterized: a laminated mat with a green and a red layers, and a monolayer, greenish-yellow mat. Bacterial communities in green, red, and yellow layers were investigated using molecular, culturing and pigment analysis methods. Pigment profiles covered a wide spectrum from chlorophylls to carotenoids. A green mat layer showed higher relative content of chlorophyll than yellow and red layers which presented higher proportion of carotenoids. Cyanobacterial isolates grow up to 55-56 degrees C and their pigment profiles showed a relatively high content of chlorophylls suggesting the importance of other bacterial groups in the mat pigment profiles. Bacterial communities were analyzed by 16S rDNA surveys showing Cyanobacteria and Chloroflexi as the mayor components of the community. Other significant members were Candidate Division OP10, Bacteroidetes, Planctomycetes and Actinobacteria. These results highlight a major participation of Cyanobacteria and Chloroflexi in thermal mat communities, and the preferential presence of Candidate Division OP10 in green mat layers. Differently colored mat layers showed characteristic bacterial communities which could be discriminated from pigment profiles and molecular surveys.

Insights into ecological roles of uncultivated bacteria in Katase hot spring sediment from long-read metagenomics

“…In this community, members of the four phylum-level clades, i.e., Chloroflexota, Deinococcota, Bacteroidota, and Armatimonadota were relatively highly abundant (7-32% of total reads). Indeed, they have been often detected as majority groups in moderately hot springs at circumneutral pH (e.g., Miller et al, 2009;Portillo et al, 2009;Song et al, 2013;Wang et al, 2013;Uribe-Lorio et al, 2019) similar to our sampling site. In contrast, archaeal members were minor (~1% of total reads) in the community.…”

Kinetics of Indigenous Nitrate Reducing Sulfide Oxidizing Activity in Microaerophilic Wastewater Biofilms

“…Collected samples were preserved with RNA-later® (Ambion, Inc.) (10x volume) and frozen at -80°C in the laboratory. RNA was extracted as in [ 36 ]. The cDNA was generated from the extracted RNA and the reverse transcription reaction was performed with ThermoScript (Invitrogen, Carlsbag, CA) 60 sec at 55°C and 5 sec at 85°C using primer 518r [ 37 ].…”