Micronucleus‐Specific Bacterium <i>Holospora elegans</i> Irreversibly Enhances Stress Gene Expression of the Host <i>Paramecium caudatum</i>

Hori, Manabu; Fujii, Kimiko; Fujishima, Masahiro

doi:10.1111/j.1550-7408.2008.00352.x

Cited by 34 publications

(24 citation statements)

References 20 publications

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“…Interestingly, symbiont-induced expression of HSP70 isoforms is shown to be permanent even after the removal of bacteria by antibiotics, indicating an epigenetic manifestation of this acquired gene expression. 34 Here, our results support a permanent activation of an individual HSP70 isoform (HSP70Pt-01) in D.24 as well as the D.starv cultures but not in other samples.…”

Section: Resultssupporting

confidence: 61%

Epigenetic regulation of serotype expression antagonizes transcriptome dynamics inParamecium tetraurelia

Cheaib

Amirabad

Nordström

et al. 2015

DNA Res

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Phenotypic variation of a single genotype is achieved by alterations in gene expression patterns. Regulation of such alterations depends on their time scale, where short-time adaptations differ from permanently established gene expression patterns maintained by epigenetic mechanisms. In the ciliate Paramecium, serotypes were described for an epigenetically controlled gene expression pattern of an individual multigene family. Paradoxically, individual serotypes can be triggered in Paramecium by alternating environments but are then stabilized by epigenetic mechanisms, thus raising the question to which extend their expression follows environmental stimuli. To characterize environmental adaptation in the context of epigenetically controlled serotype expression, we used RNA-seq to characterize transcriptomes of serotype pure cultures. The resulting vegetative transcriptome resource is first analysed for genes involved in the adaptive response to the altered environment. Secondly, we identified groups of genes that do not follow the adaptive response but show co-regulation with the epigenetically controlled serotype system, suggesting that their gene expression pattern becomes manifested by similar mechanisms. In our experimental set-up, serotype expression and the entire group of co-regulated genes were stable among environmental changes and only heat-shock genes altered expression of these gene groups. The data suggest that the maintenance of these gene expression patterns in a lineage represents epigenetically controlled robustness counteracting short-time adaptation processes.

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Section: Resultssupporting

confidence: 61%

Epigenetic regulation of serotype expression antagonizes transcriptome dynamics inParamecium tetraurelia

Cheaib

Amirabad

Nordström

et al. 2015

DNA Res

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“…However, they are not significantly heat-inducible [51], while P. caudatum ER-type hsp70 s seem to be. Therefore, experiments on the gene expression of these ER-type hsp70 genes investigating the effect of endosymbionts [46,52] or other stressors would be valuable in unveiling their role in the stress response of Paramecium. …”

Section: Discussionmentioning

confidence: 99%

Convergent evolution of heat-inducibility during subfunctionalization of the Hsp70 gene family

2013

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BackgroundHeat-shock proteins of the 70 kDa family (Hsp70s) are essential chaperones required for key cellular functions. In eukaryotes, four subfamilies can be distinguished according to their function and localisation in different cellular compartments: cytosol, endoplasmic reticulum, mitochondria and chloroplasts. Generally, multiple cytosol-type Hsp70s can be found in metazoans that show either constitutive expression and/or stress-inducibility, arguing for the evolution of different tasks and functions. Information about the hsp70 copy number and diversity in microbial eukaryotes is, however, scarce, and detailed knowledge about the differential gene expression in most protists is lacking. Therefore, we have characterised the Hsp70 gene family of Paramecium caudatum to gain insight into the evolution and differential heat stress response of the distinct family members in protists and to investigate the diversification of eukaryotic hsp70s focusing on the evolution of heat-inducibility.ResultsEleven putative hsp70 genes could be detected in P. caudatum comprising homologs of three major Hsp70-subfamilies. Phylogenetic analyses revealed five evolutionarily distinct Hsp70-groups, each with a closer relationship to orthologous sequences of Paramecium tetraurelia than to another P. caudatum Hsp70-group. These highly diverse, paralogous groups resulted from duplications preceding Paramecium speciation, underwent divergent evolution and were subject to purifying selection. Heat-shock treatments were performed to test for differential expression patterns among the five Hsp70-groups as well as for a functional conservation within Paramecium. These treatments induced exceptionally high mRNA up-regulations in one cytosolic group with a low basal expression, indicative for the major heat inducible hsp70s. All other groups showed comparatively high basal expression levels and moderate heat-inducibility, signifying constitutively expressed genes. Comparative EST analyses for P. tetraurelia hsp70s unveiled a corresponding expression pattern, which supports a functionally conserved evolution of the Hsp70 gene family in Paramecium.ConclusionsOur analyses suggest an independent evolution of the heat-inducible cytosol-type hsp70s in Paramecium and in its close relative Tetrahymena, as well as within higher eukaryotes. This result indicates convergent evolution during hsp70 subfunctionalization and implies that heat-inducibility evolved several times during the course of eukaryotic evolution.

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“…were also noted in Paramecium sp. and they inhabited the macro-and micronucleus of the host (Fokin et al 2004;Hori et al 2008), however the range of their functions was much broader, e.g. H. undulata increased host resistance to osmotic stress (Duncan et al 2010) and tolerance to heat-shock (Fujishima et al 2005).…”

Section: Resultsmentioning

confidence: 99%

Detection of a new bacterium of the family Holosporaceae (Alphaproteobacteria: Holosporales) associated with the oribatid mite Achipteria coleoptrata

Konecka

Olszanowski

2019

Biologia

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We detected an unknown bacterium in Achipteria coleoptrata (Acari: Oribatida). Its 16S rDNA gene sequence showed 89% identity to the endosymbiont BCandidatus Nucleicultrix amoebiphila^from amoebae and BCandidatus Gortzia sp.^from ciliates. Phylogenetic analysis revealed that the microorganism is a member of the family Holosporaceae, order Holosporales of Alphaproteobacteria. Its occurrence in Oribatida is enigmatic. It cannot be excluded that it is a symbiont of Oribatida as well as it is an endosymbiont of a smaller, even unicellular, organisms living inside the mite. The issue of the occurrence of this microorganism is interesting and further research is needed to gain the knowledge of its role and the nature of bacterium-host interaction.

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Micronucleus‐Specific Bacterium Holospora elegans Irreversibly Enhances Stress Gene Expression of the Host Paramecium caudatum

Cited by 34 publications

References 20 publications

Epigenetic regulation of serotype expression antagonizes transcriptome dynamics inParamecium tetraurelia

Epigenetic regulation of serotype expression antagonizes transcriptome dynamics inParamecium tetraurelia

Convergent evolution of heat-inducibility during subfunctionalization of the Hsp70 gene family

Detection of a new bacterium of the family Holosporaceae (Alphaproteobacteria: Holosporales) associated with the oribatid mite Achipteria coleoptrata

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