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Isolation of diverse members of the Aquificales from geothermal springs in Tengchong, China.

Hedlund BP, Reysenbach AL, Huang L, Ong JC, Liu Z, Dodsworth JA, Ahmed R, Williams AJ, Briggs BR, Liu Y, Hou W, Dong H - Front Microbiol (2015)

Bottom Line: We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant.Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum.All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA ; Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA.

ABSTRACT
The order Aquificales (phylum Aquificae) consists of thermophilic and hyperthermophilic bacteria that are prominent in many geothermal systems, including those in Tengchong, Yunnan Province, China. However, Aquificales have not previously been isolated from Tengchong. We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant. Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum. The additional strain may represent a new genus in the Hydrogenothermaceae. All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.

No MeSH data available.


Related in: MedlinePlus

Phylogenetic analysis. Maximum-likelihood (ML) phylogeny of the Aquificales including all genera and type strains of all species in the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, as well as closely related clones from cultivation-independent studies. Bootstrap values represent 100 replicates for ML and 1,000 replicates for neighbor joining (NJ). Similar analyses with a Lane mask or without an outgroup sequence yielded similar results. Bootstrap support for nodes supported by<80% recovery from both methods is not shown. Bar, 0.01 changes per nucleotide. The outgroup was Methanocaldococcus jannaschii (AB603516).
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Figure 2: Phylogenetic analysis. Maximum-likelihood (ML) phylogeny of the Aquificales including all genera and type strains of all species in the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, as well as closely related clones from cultivation-independent studies. Bootstrap values represent 100 replicates for ML and 1,000 replicates for neighbor joining (NJ). Similar analyses with a Lane mask or without an outgroup sequence yielded similar results. Bootstrap support for nodes supported by<80% recovery from both methods is not shown. Bar, 0.01 changes per nucleotide. The outgroup was Methanocaldococcus jannaschii (AB603516).

Mentions: Phylogenetic analysis based on near-complete 16S rRNA genes showed that the strains belonged to the families Aquificaceae and Hydrogenothemaceae. Two Hydrogenobacter strains were isolated, designated T-2 and T-8, from sites differing in pH by > 2.5 units. They were grown in media with pH similar to their environmental source, although both were closely related to “Hydrogenobacter subterraneus” (Table 2; Figure 2). Both strains belonged to a species-level (98.65% identity; Kim et al., 2014) operational taxonomic unit (OTU) that comprised >50% of 16S rRNA gene sequence tags in either sediments or the bulk water in most circumneutral geothermal sites in both Rehai and Ruidian (Dientan) geothermal fields (Hou et al., 2013), including streamer and sediment communities in Guminquan, from which strain T-2 was isolated. However, the most abundant sequence within that OTU shared only 98.84% identity with strains T-2 and T-8, whereas the identical sequence to T-2 and T-8 was a rare variant in the cultivation-independent datasets. The other isolate belonging to the Aquificaceae, strain T-6, was isolated from the acidic pool, Diretiyanqu. Strain T-6 branched within the genus Hydrogenobaculum but was distant from the only validly described species, Hydrogenobaculum acidophilus, as well as other isolates from Yellowstone National Park (Table 2; Figure 2). Strain T-6 belonged to an OTU that comprised 31 to 66% of 16S rRNA gene sequence tags from pools ranging from 55 to 65°C from Diretiyanqu, the system of small acidic pools from which the strain was isolated (Hou et al., 2013). Within these systems, the dominant OTU was identical to T-6. Sulfurihydrogenibium strain T-7 was closely related to Sulfurihydrogenibium subterraneum and tentatively identified as a member of that species. Within the genus Sulfurihydrogenibium, Sulfurihydrogenibium subterraneum HGMK-1T, and strain T-7 branched with 16S rRNA gene clones from Asia (Japan and Taiwan), potentially representing a species exclusive to Asia (Figure 2). T-5, the other strain that branched from within the Hydrogenothermaceae, was only distantly related to cultivated strains of Sulfurihydrogenibium and Venenivibrio and branched with 16S rRNA gene clones from hot springs in China and Thailand (Table 2; Figure 2; JX298759 and KC831413, unpublished). Aside from strain T-7, the 16S rRNA gene identity between each new isolate and the most closely related species was well below the 16S rRNA gene identity threshold suggested to delimit bacterial species (98.65%; Kim et al., 2014), and strains T-6 and T-5 were also below the median 16S rRNA gene identity circumscribing bacterial genera (Yarza et al., 2014). Formal taxonomic treatment of these isolates will be determined pending detailed physiological and genomic analysis.


Isolation of diverse members of the Aquificales from geothermal springs in Tengchong, China.

Hedlund BP, Reysenbach AL, Huang L, Ong JC, Liu Z, Dodsworth JA, Ahmed R, Williams AJ, Briggs BR, Liu Y, Hou W, Dong H - Front Microbiol (2015)

Phylogenetic analysis. Maximum-likelihood (ML) phylogeny of the Aquificales including all genera and type strains of all species in the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, as well as closely related clones from cultivation-independent studies. Bootstrap values represent 100 replicates for ML and 1,000 replicates for neighbor joining (NJ). Similar analyses with a Lane mask or without an outgroup sequence yielded similar results. Bootstrap support for nodes supported by<80% recovery from both methods is not shown. Bar, 0.01 changes per nucleotide. The outgroup was Methanocaldococcus jannaschii (AB603516).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4343020&req=5

Figure 2: Phylogenetic analysis. Maximum-likelihood (ML) phylogeny of the Aquificales including all genera and type strains of all species in the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, as well as closely related clones from cultivation-independent studies. Bootstrap values represent 100 replicates for ML and 1,000 replicates for neighbor joining (NJ). Similar analyses with a Lane mask or without an outgroup sequence yielded similar results. Bootstrap support for nodes supported by<80% recovery from both methods is not shown. Bar, 0.01 changes per nucleotide. The outgroup was Methanocaldococcus jannaschii (AB603516).
Mentions: Phylogenetic analysis based on near-complete 16S rRNA genes showed that the strains belonged to the families Aquificaceae and Hydrogenothemaceae. Two Hydrogenobacter strains were isolated, designated T-2 and T-8, from sites differing in pH by > 2.5 units. They were grown in media with pH similar to their environmental source, although both were closely related to “Hydrogenobacter subterraneus” (Table 2; Figure 2). Both strains belonged to a species-level (98.65% identity; Kim et al., 2014) operational taxonomic unit (OTU) that comprised >50% of 16S rRNA gene sequence tags in either sediments or the bulk water in most circumneutral geothermal sites in both Rehai and Ruidian (Dientan) geothermal fields (Hou et al., 2013), including streamer and sediment communities in Guminquan, from which strain T-2 was isolated. However, the most abundant sequence within that OTU shared only 98.84% identity with strains T-2 and T-8, whereas the identical sequence to T-2 and T-8 was a rare variant in the cultivation-independent datasets. The other isolate belonging to the Aquificaceae, strain T-6, was isolated from the acidic pool, Diretiyanqu. Strain T-6 branched within the genus Hydrogenobaculum but was distant from the only validly described species, Hydrogenobaculum acidophilus, as well as other isolates from Yellowstone National Park (Table 2; Figure 2). Strain T-6 belonged to an OTU that comprised 31 to 66% of 16S rRNA gene sequence tags from pools ranging from 55 to 65°C from Diretiyanqu, the system of small acidic pools from which the strain was isolated (Hou et al., 2013). Within these systems, the dominant OTU was identical to T-6. Sulfurihydrogenibium strain T-7 was closely related to Sulfurihydrogenibium subterraneum and tentatively identified as a member of that species. Within the genus Sulfurihydrogenibium, Sulfurihydrogenibium subterraneum HGMK-1T, and strain T-7 branched with 16S rRNA gene clones from Asia (Japan and Taiwan), potentially representing a species exclusive to Asia (Figure 2). T-5, the other strain that branched from within the Hydrogenothermaceae, was only distantly related to cultivated strains of Sulfurihydrogenibium and Venenivibrio and branched with 16S rRNA gene clones from hot springs in China and Thailand (Table 2; Figure 2; JX298759 and KC831413, unpublished). Aside from strain T-7, the 16S rRNA gene identity between each new isolate and the most closely related species was well below the 16S rRNA gene identity threshold suggested to delimit bacterial species (98.65%; Kim et al., 2014), and strains T-6 and T-5 were also below the median 16S rRNA gene identity circumscribing bacterial genera (Yarza et al., 2014). Formal taxonomic treatment of these isolates will be determined pending detailed physiological and genomic analysis.

Bottom Line: We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant.Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum.All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA ; Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA.

ABSTRACT
The order Aquificales (phylum Aquificae) consists of thermophilic and hyperthermophilic bacteria that are prominent in many geothermal systems, including those in Tengchong, Yunnan Province, China. However, Aquificales have not previously been isolated from Tengchong. We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant. Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum. The additional strain may represent a new genus in the Hydrogenothermaceae. All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.

No MeSH data available.


Related in: MedlinePlus