Oxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements.

2.50
Hdl Handle:
http://hdl.handle.net/10033/581404
Title:
Oxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements.
Authors:
Soora, Maya; Tomasch, Jürgen; Wang, Hui; Michael, Victoria; Petersen, Jörn; Engelen, Bert; Wagner-Döbler, Irene; Cypionka, Heribert
Abstract:
Aerobic anoxygenic phototrophic bacteria (AAP) are abundant in the photic zone of the marine environment. Dinoroseobacter shibae, a representative of the Roseobacter group, converts light into additional energy that enhances its survival especially under starvation. However, light exposure results in the production of cytotoxic reactive oxygen species in AAPs. Here we investigated the response of D. shibae to starvation and oxidative stress, focusing on the role of extrachromosomal elements (ECRs). D. shibae possessing five ECRs (three plasmids and two chromids) was starved for 4 weeks either in the dark or under light/dark cycles and the survival was monitored. Transcriptomics showed that on the chromosome genes with a role in oxidative stress response and photosynthesis were differentially expressed during the light period. Most extrachromosomal genes in contrast showed a general loss of transcriptional activity, especially in dark-starved cells. The observed decrease of gene expression was not due to plasmid loss, as all five ECRs were maintained in the cells. Interestingly, the genes on the 72-kb chromid were the least downregulated, and one region with genes of the oxygen stress response and a light-dependent protochlorophyllide reductase of cyanobacterial origin was strongly activated under the light/dark cycle. A Δ72-kb curing mutant lost the ability to survive under starvation in a light/dark cycle demonstrating the essential role of this chromid for adaptation to starvation and oxidative stress. Our data moreover suggest that the other four ECRs of D. shibae have no vital function under the investigated conditions and therefore were transcriptionally silenced.
Affiliation:
HZI Helmholtzzentrum für Infektionsforschung
Citation:
Oxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements. 2015, 6:233 Front Microbiol
Journal:
Frontiers in microbiology
Issue Date:
2015
URI:
http://hdl.handle.net/10033/581404
DOI:
10.3389/fmicb.2015.00233
PubMed ID:
25859246
Type:
Article
Language:
en
ISSN:
1664-302X
Appears in Collections:
collections of the research group microbial communication (KOM)

Full metadata record

DC FieldValue Language
dc.contributor.authorSoora, Mayaen
dc.contributor.authorTomasch, Jürgenen
dc.contributor.authorWang, Huien
dc.contributor.authorMichael, Victoriaen
dc.contributor.authorPetersen, Jörnen
dc.contributor.authorEngelen, Berten
dc.contributor.authorWagner-Döbler, Ireneen
dc.contributor.authorCypionka, Heriberten
dc.date.accessioned2015-10-29T10:05:06Zen
dc.date.available2015-10-29T10:05:06Zen
dc.date.issued2015en
dc.identifier.citationOxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements. 2015, 6:233 Front Microbiolen
dc.identifier.issn1664-302Xen
dc.identifier.pmid25859246en
dc.identifier.doi10.3389/fmicb.2015.00233en
dc.identifier.urihttp://hdl.handle.net/10033/581404en
dc.description.abstractAerobic anoxygenic phototrophic bacteria (AAP) are abundant in the photic zone of the marine environment. Dinoroseobacter shibae, a representative of the Roseobacter group, converts light into additional energy that enhances its survival especially under starvation. However, light exposure results in the production of cytotoxic reactive oxygen species in AAPs. Here we investigated the response of D. shibae to starvation and oxidative stress, focusing on the role of extrachromosomal elements (ECRs). D. shibae possessing five ECRs (three plasmids and two chromids) was starved for 4 weeks either in the dark or under light/dark cycles and the survival was monitored. Transcriptomics showed that on the chromosome genes with a role in oxidative stress response and photosynthesis were differentially expressed during the light period. Most extrachromosomal genes in contrast showed a general loss of transcriptional activity, especially in dark-starved cells. The observed decrease of gene expression was not due to plasmid loss, as all five ECRs were maintained in the cells. Interestingly, the genes on the 72-kb chromid were the least downregulated, and one region with genes of the oxygen stress response and a light-dependent protochlorophyllide reductase of cyanobacterial origin was strongly activated under the light/dark cycle. A Δ72-kb curing mutant lost the ability to survive under starvation in a light/dark cycle demonstrating the essential role of this chromid for adaptation to starvation and oxidative stress. Our data moreover suggest that the other four ECRs of D. shibae have no vital function under the investigated conditions and therefore were transcriptionally silenced.en
dc.language.isoenen
dc.titleOxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements.en
dc.typeArticleen
dc.contributor.departmentHZI Helmholtzzentrum für Infektionsforschungen
dc.identifier.journalFrontiers in microbiologyen

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