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  1. Article: Mutation of Gly195 of the ChlH Subunit of Mg-chelatase Reduces Chlorophyll and Further Disrupts PS II Assembly in a Ycf48-Deficient Strain of Synechocystis sp. PCC 6803.

    Crawford, Tim S / Eaton-Rye, Julian J / Summerfield, Tina C

    Frontiers in plant science

    2016  Volume 7, Page(s) 1060

    Abstract: Biogenesis of the photosystems in oxygenic phototrophs requires co-translational insertion of chlorophyll a. The first committed step of chlorophyll a biosynthesis is the insertion of a Mg(2+) ion into the tetrapyrrole intermediate protoporphyrin IX, ... ...

    Abstract Biogenesis of the photosystems in oxygenic phototrophs requires co-translational insertion of chlorophyll a. The first committed step of chlorophyll a biosynthesis is the insertion of a Mg(2+) ion into the tetrapyrrole intermediate protoporphyrin IX, catalyzed by Mg-chelatase. We have identified a Synechocystis sp. PCC 6803 strain with a spontaneous mutation in chlH that results in a Gly195 to Glu substitution in a conserved region of the catalytic subunit of Mg-chelatase. Mutant strains containing the ChlH Gly195 to Glu mutation were generated using a two-step protocol that introduced the chlH gene into a putative neutral site in the chromosome prior to deletion of the native gene. The Gly195 to Glu mutation resulted in strains with decreased chlorophyll a. Deletion of the PS II assembly factor Ycf48 in a strain carrying the ChlH Gly195 to Glu mutation did not grow photoautotrophically. In addition, the ChlH-G195E:ΔYcf48 strain showed impaired PS II activity and decreased assembly of PS II centers in comparison to a ΔYcf48 strain. We suggest decreased chlorophyll in the ChlH-G195E mutant provides a background to screen for the role of assembly factors that are not essential under optimal growth conditions.
    Language English
    Publishing date 2016-07-20
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2711035-7
    ISSN 1664-462X
    ISSN 1664-462X
    DOI 10.3389/fpls.2016.01060
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Comparison of D1´- and D1-containing PS II reaction centre complexes under different environmental conditions in Synechocystis sp. PCC 6803.

    Crawford, Tim S / Hanning, Kyrin R / Chua, Jocelyn P S / Eaton-Rye, Julian J / Summerfield, Tina C

    Plant, cell & environment

    2016  Volume 39, Issue 8, Page(s) 1715–1726

    Abstract: In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, ... ...

    Abstract In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, including low-oxygen-induction of psbA1 encoding the D1´ protein in Synechocystis sp. PCC 6803. The psbA1 gene is also transiently up-regulated in high light, and its deletion has been reported to increase ammonium-induced photoinhibition. Therefore we investigated the role of D1´-containing PS II centres under different environmental conditions. A strain containing only D1´-PS II centres under aerobic conditions exhibited increased sensitivity to ammonium chloride and high light compared to a D1-containing strain. Additionally a D1´-PS II strain was outperformed by a D1-PS II strain under normal conditions; however, a strain containing low-oxygen-induced D1´-PS II centres was more resilient under high light than an equivalent D1 strain. These D1´-containing centres had chlorophyll a fluorescence characteristics indicative of altered forward electron transport and back charge recombination with the donor side of PS II. Our results indicate D1´-PS II centres are important in the reconfiguration of thylakoid electron transport in response to high light and low oxygen.
    Language English
    Publishing date 2016-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 391893-2
    ISSN 1365-3040 ; 0140-7791
    ISSN (online) 1365-3040
    ISSN 0140-7791
    DOI 10.1111/pce.12738
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Comparison of D1´‐ and D1‐containing PS II reaction centre complexes under different environmental conditions in Synechocystis sp. PCC 6803

    Crawford, Tim S / Jocelyn P.S. Chua / Julian J. Eaton‐Rye / Kyrin R. Hanning / Tina C. Summerfield

    Plant, cell and environment. 2016 Aug., v. 39, no. 8

    2016  

    Abstract: In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, ... ...

    Abstract In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, including low‐oxygen‐induction of psbA1 encoding the D1´ protein in Synechocystis sp. PCC 6803. The psbA1 gene is also transiently up‐regulated in high light, and its deletion has been reported to increase ammonium‐induced photoinhibition. Therefore we investigated the role of D1´‐containing PS II centres under different environmental conditions. A strain containing only D1´‐PS II centres under aerobic conditions exhibited increased sensitivity to ammonium chloride and high light compared to a D1‐containing strain. Additionally a D1´‐PS II strain was outperformed by a D1‐PS II strain under normal conditions; however, a strain containing low‐oxygen‐induced D1´‐PS II centres was more resilient under high light than an equivalent D1 strain. These D1´‐containing centres had chlorophyll a fluorescence characteristics indicative of altered forward electron transport and back charge recombination with the donor side of PS II. Our results indicate D1´‐PS II centres are important in the reconfiguration of thylakoid electron transport in response to high light and low oxygen.
    Keywords aerobic conditions ; ammonium chloride ; chlorophyll ; D1 protein ; electron transfer ; fluorescence ; gene expression regulation ; genes ; oxygen ; photoinhibition ; photosystem II ; stress response ; Synechocystis ; thylakoids ; transcription (genetics)
    Language English
    Dates of publication 2016-08
    Size p. 1715-1726.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 391893-2
    ISSN 1365-3040 ; 0140-7791
    ISSN (online) 1365-3040
    ISSN 0140-7791
    DOI 10.1111/pce.12738
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Bonn / Germany

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  4. Article ; Online: Environmental pH affects photoautotrophic growth of Synechocystis sp. PCC 6803 strains carrying mutations in the lumenal proteins of PSII.

    Summerfield, Tina C / Crawford, Tim S / Young, Roger D / Chua, Jocelyn P S / Macdonald, Rebecca L / Sherman, Louis A / Eaton-Rye, Julian J

    Plant & cell physiology

    2013  Volume 54, Issue 6, Page(s) 859–874

    Abstract: Synechocystis sp. strain PCC 6803 grows photoautotrophically across a broad pH range, but wild-type cultures reach a higher density at elevated pH; however, photoheterotrophic growth is similar at high and neutral pH. A number of PSII mutants each ... ...

    Abstract Synechocystis sp. strain PCC 6803 grows photoautotrophically across a broad pH range, but wild-type cultures reach a higher density at elevated pH; however, photoheterotrophic growth is similar at high and neutral pH. A number of PSII mutants each lacking at least one lumenal extrinsic protein, and carrying a second PSII lumenal mutation, are able to grow photoautotrophically in BG-11 medium at pH 10.0, but not pH 7.5. We investigated the basis of this pH effect and observed no pH-specific change in variable fluorescence yield from PSII centers of the wild type or the pH-dependent ΔPsbO:ΔPsbU and ΔPsbV:ΔCyanoQ strains; however, 77 K fluorescence emission spectra indicated increased coupling of the phycobilisome (PBS) antenna at pH 10.0 in all mutants. DNA microarray data showed a cell-wide response to transfer from pH 10.0 to pH 7.5, including decreased mRNA levels of a number of oxidative stress-responsive transcripts. We hypothesize that this transcriptional response led to increased tolerance against reactive oxygen species and in particular singlet oxygen. This response enabled photoautotrophic growth of the PSII mutants at pH 10.0. This hypothesis was supported by increased resistance of all strains to rose bengal at pH 10.0 compared with pH 7.5.
    MeSH term(s) Autotrophic Processes/drug effects ; Autotrophic Processes/radiation effects ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Buffers ; Chlorophyll/metabolism ; Culture Media/pharmacology ; Environment ; Gene Expression Regulation, Bacterial/drug effects ; Gene Expression Regulation, Bacterial/radiation effects ; Genes, Bacterial/genetics ; Heterotrophic Processes/drug effects ; Heterotrophic Processes/radiation effects ; Hydrogen-Ion Concentration/drug effects ; Kinetics ; Models, Biological ; Mutation/genetics ; Oxidative Stress/drug effects ; Oxidative Stress/genetics ; Oxidative Stress/radiation effects ; Photosystem II Protein Complex/genetics ; Photosystem II Protein Complex/metabolism ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; Rose Bengal/pharmacology ; Singlet Oxygen/pharmacology ; Spectrometry, Fluorescence ; Synechocystis/drug effects ; Synechocystis/genetics ; Synechocystis/growth & development ; Synechocystis/metabolism ; Transcription, Genetic/drug effects ; Transcription, Genetic/radiation effects
    Chemical Substances Bacterial Proteins ; Buffers ; Culture Media ; Photosystem II Protein Complex ; RNA, Messenger ; Chlorophyll (1406-65-1) ; Singlet Oxygen (17778-80-2) ; Rose Bengal (1ZPG1ELY14) ; chlorophyll a (YF5Q9EJC8Y)
    Language English
    Publishing date 2013-06
    Publishing country Japan
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 208907-5
    ISSN 1471-9053 ; 0032-0781
    ISSN (online) 1471-9053
    ISSN 0032-0781
    DOI 10.1093/pcp/pct036
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Bonn / Germany

    Z 79/710: Show issues

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