Limits...
Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts.

Schreiber L, Kjeldsen KU, Funch P, Jensen J, Obst M, López-Legentil S, Schramm A - Front Microbiol (2016)

Bottom Line: The strains tested negative for cytotoxic or antibacterial activity.Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx.The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioscience, Center for Geomicrobiology and Section for Microbiology, Aarhus University Aarhus, Denmark.

ABSTRACT
Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25-100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas.

No MeSH data available.


Related in: MedlinePlus

Dendrogram of 16S rRNA gene sequences of the Endozoicomonas clade. Strict consensus representation (i.e., the shown branching patterns and subclades were present in all source trees) of phylogenetic trees calculated by MP, ML, and BI analyses using only nearly full-length (≥1400 bp) 16S rRNA gene sequences. The dendrogram was rooted with sequences of the genera Zooshikella and Hahella (not shown). The dendrogram was truncated (indicated with dotted line and arrow) and does not show an additional 80 sequences of bacteria associated with coral hosts. Host species and accession numbers of single sequences are shown in brackets. For subclades, numbers of containing sequences are shown in brackets. Major host groups are indicated with silhouette symbols. Sequences of ascidian origin are additionally marked with green. Branch lengths do not represent phylogenetic distances.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4940369&req=5

Figure 1: Dendrogram of 16S rRNA gene sequences of the Endozoicomonas clade. Strict consensus representation (i.e., the shown branching patterns and subclades were present in all source trees) of phylogenetic trees calculated by MP, ML, and BI analyses using only nearly full-length (≥1400 bp) 16S rRNA gene sequences. The dendrogram was rooted with sequences of the genera Zooshikella and Hahella (not shown). The dendrogram was truncated (indicated with dotted line and arrow) and does not show an additional 80 sequences of bacteria associated with coral hosts. Host species and accession numbers of single sequences are shown in brackets. For subclades, numbers of containing sequences are shown in brackets. Major host groups are indicated with silhouette symbols. Sequences of ascidian origin are additionally marked with green. Branch lengths do not represent phylogenetic distances.

Mentions: Most of the detected bacteria are known constituents of seawater or marine sediments (Buchan et al., 2005; Zhao et al., 2009; Bowman, 2014; Garcia and Müller, 2014; Gomez-Gil et al., 2014; Lastovica et al., 2014; López-Pérez and Rodriguez-Valera, 2014) and were likely associated with the sampled pharynges due to the ascidians' filter feeding. However, members of the Vibrionaceae (Gomez-Gil et al., 2014) and the genus Endozoicomonas (Kurahashi and Yokota, 2007; Yang et al., 2010; Nishijima et al., 2013; Pike et al., 2013; Hyun et al., 2014; Appolinario et al., 2016) have also been detected in association with other marine animals and thereby may represent bacteria with a more stable association with the sampled ascidians. The genus Endozoicomonas is of special interest as bacteria from this clade are only very rarely detected outside marine animals; only five sequences out of more than 1000 publically available Endozoicomonas 16S rRNA gene sequences originate from a non-marine-animal source (this study; Figure 1). This result and the detection of Endozoicomonas in 12 of the 17 initially screened ascidian specimens (culturing approach: 2/5, culture-independent approach: 10/12) indicated a symbiotic interaction between Endozoicomonas and ascidians, and consequently led us to focus this study on exploring this interaction.


Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts.

Schreiber L, Kjeldsen KU, Funch P, Jensen J, Obst M, López-Legentil S, Schramm A - Front Microbiol (2016)

Dendrogram of 16S rRNA gene sequences of the Endozoicomonas clade. Strict consensus representation (i.e., the shown branching patterns and subclades were present in all source trees) of phylogenetic trees calculated by MP, ML, and BI analyses using only nearly full-length (≥1400 bp) 16S rRNA gene sequences. The dendrogram was rooted with sequences of the genera Zooshikella and Hahella (not shown). The dendrogram was truncated (indicated with dotted line and arrow) and does not show an additional 80 sequences of bacteria associated with coral hosts. Host species and accession numbers of single sequences are shown in brackets. For subclades, numbers of containing sequences are shown in brackets. Major host groups are indicated with silhouette symbols. Sequences of ascidian origin are additionally marked with green. Branch lengths do not represent phylogenetic distances.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940369&req=5

Figure 1: Dendrogram of 16S rRNA gene sequences of the Endozoicomonas clade. Strict consensus representation (i.e., the shown branching patterns and subclades were present in all source trees) of phylogenetic trees calculated by MP, ML, and BI analyses using only nearly full-length (≥1400 bp) 16S rRNA gene sequences. The dendrogram was rooted with sequences of the genera Zooshikella and Hahella (not shown). The dendrogram was truncated (indicated with dotted line and arrow) and does not show an additional 80 sequences of bacteria associated with coral hosts. Host species and accession numbers of single sequences are shown in brackets. For subclades, numbers of containing sequences are shown in brackets. Major host groups are indicated with silhouette symbols. Sequences of ascidian origin are additionally marked with green. Branch lengths do not represent phylogenetic distances.
Mentions: Most of the detected bacteria are known constituents of seawater or marine sediments (Buchan et al., 2005; Zhao et al., 2009; Bowman, 2014; Garcia and Müller, 2014; Gomez-Gil et al., 2014; Lastovica et al., 2014; López-Pérez and Rodriguez-Valera, 2014) and were likely associated with the sampled pharynges due to the ascidians' filter feeding. However, members of the Vibrionaceae (Gomez-Gil et al., 2014) and the genus Endozoicomonas (Kurahashi and Yokota, 2007; Yang et al., 2010; Nishijima et al., 2013; Pike et al., 2013; Hyun et al., 2014; Appolinario et al., 2016) have also been detected in association with other marine animals and thereby may represent bacteria with a more stable association with the sampled ascidians. The genus Endozoicomonas is of special interest as bacteria from this clade are only very rarely detected outside marine animals; only five sequences out of more than 1000 publically available Endozoicomonas 16S rRNA gene sequences originate from a non-marine-animal source (this study; Figure 1). This result and the detection of Endozoicomonas in 12 of the 17 initially screened ascidian specimens (culturing approach: 2/5, culture-independent approach: 10/12) indicated a symbiotic interaction between Endozoicomonas and ascidians, and consequently led us to focus this study on exploring this interaction.

Bottom Line: The strains tested negative for cytotoxic or antibacterial activity.Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx.The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioscience, Center for Geomicrobiology and Section for Microbiology, Aarhus University Aarhus, Denmark.

ABSTRACT
Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25-100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas.

No MeSH data available.


Related in: MedlinePlus