39648998 OR Light quality, oxygenic photosynthesis and more
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Light quality significantly influences plant metabolism, growth and development. Recently, we have demonstrated that leaves of barley and other plant species grown under monochromatic green light (500-590 nm) accumulated a large pool of chlorophyll a (Chl a) intermediates with incomplete hydrogenation of their phytyl chains. In this work, we studied accumulation of these geranylgeranylated Chls a and b in pigment-protein complexes (PPCs) of Arabidopsis plants acclimated to green light and their structural-functional consequences on the photosynthetic apparatus. We found that geranylgeranylated Chls are present in all major PPCs, although their presence was more pronounced in light-harvesting complex II (LHCII) and less prominent in supercomplexes of photosystem II (PSII). Accumulation of geranylgeranylated Chls hampered the formation of PSII and PSI super- and megacomplexes in the thylakoid membranes as well as their assembly into chiral macrodomains; it also lowered the temperature stability of the PPCs, especially that of LHCII trimers, which led to their monomerization and an anomaly in the photoprotective mechanism of non-photochemical quenching. Role of geranylgeranylated Chls in adverse effects on photosynthetic apparatus of plants acclimated to green light is discussed.
Low oxygen conditions occur in grass sites due to high and frequent precipitation, poor soil quality, and over-irrigation followed by slow drainage. Three warm-season and one cool-season grass were analyzed at metabolic level during a time-course experiment performed in a controlled anoxic environment. Prolonged oxygen depletion proved detrimental by leading to premature death to all the species, with the exception of seashore paspalum. Moreover, the anoxia tolerance observed in these grasses has been associated with slow use of carbohydrates, rather than with their relative abundance, which was more important than their antioxidant capacity. Further physiological characterization of eight seashore paspalum genotypes to anoxia was also performed, by examining the variation in photosystem II (PSII) efficiency and gas exchange during post-anoxia recovery. Multivariate analysis highlighted the presence of three main clusters of seashore paspalum genotypes, characterized by different ability to restore the PSII photochemistry during recovery after one day of anoxia. Taken together, our data demonstrate that the analysis of post-anoxia recovery of fluorescence and gas exchange parameters can represent a fast and reliable indicator for selecting species and cultivars more able to acclimate their photosynthetic apparatus.
- MeSH
- alkoholdehydrogenasa metabolismus MeSH
- anaerobióza účinky záření MeSH
- cukry metabolismus MeSH
- druhová specificita MeSH
- faktorová analýza statistická MeSH
- fotosyntéza * účinky záření MeSH
- fotosystém II (proteinový komplex) metabolismus MeSH
- fyziologická adaptace účinky záření MeSH
- genotyp MeSH
- kvantitativní znak dědičný * MeSH
- kyslík metabolismus MeSH
- lipnicovité enzymologie genetika fyziologie účinky záření MeSH
- roční období MeSH
- rozpustnost MeSH
- světlo MeSH
- Publikační typ
- časopisecké články MeSH
The cyanobacterium Synechocystis sp. PCC 6803 contains four members of the FtsH protease family. One of these, FtsH (slr0228), has been implicated recently in the repair of photodamaged photosystem II (PSII) complexes. We have demonstrated here, using a combination of blue native PAGE, radiolabeling, and immunoblotting, that FtsH (slr0228) is required for selective replacement of the D1 reaction center subunit in both wild type PSII complexes and in PSII subcomplexes lacking the PSII chlorophyll a-binding subunit CP43. To test whether FtsH (slr0228) has a more general role in protein quality control in vivo, we have studied the synthesis and degradation of PSII subunits in wild type and in defined insertion and missense mutants incapable of proper assembly of the PSII holoenzyme. We discovered that, when the gene encoding FtsH (slr0228) was disrupted in these strains, the overall level of assembly intermediates and unassembled PSII proteins markedly increased. Pulse-chase experiments showed that this was due to reduced rates of degradation in vivo. Importantly, analysis of epitope-tagged and green fluorescent protein-tagged strains revealed that slr0228 was present in the thylakoid and not the cytoplasmic membrane. Overall, our results show that FtsH (slr0228) plays an important role in controlling the removal of PSII subunits from the thylakoid membrane and is not restricted to selective D1 turnover.
- MeSH
- 2D gelová elektroforéza MeSH
- biochemické jevy MeSH
- biochemie MeSH
- buněčná membrána metabolismus MeSH
- časové faktory MeSH
- chloroplasty metabolismus MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- epitopy chemie MeSH
- financování organizované MeSH
- fotosystém II (proteinový komplex) metabolismus MeSH
- genotyp MeSH
- imunoblotting MeSH
- konfokální mikroskopie MeSH
- metaloendopeptidasy fyziologie chemie MeSH
- missense mutace MeSH
- mutace MeSH
- plazmidy metabolismus MeSH
- proteasy chemie MeSH
- světlo MeSH
- Synechocystis metabolismus MeSH
- tylakoidy metabolismus MeSH
- vazba proteinů MeSH
- zelené fluorescenční proteiny chemie metabolismus MeSH
The membrane-embedded FtsH proteases found in bacteria, chloroplasts, and mitochondria are involved in diverse cellular processes including protein quality control and regulation. The genome of the model cyanobacterium Synechocystis sp PCC 6803 encodes four FtsH homologs designated FtsH1 to FtsH4. The FtsH3 homolog is present in two hetero-oligomeric complexes: FtsH2/3, which is responsible for photosystem II quality control, and the essential FtsH1/3 complex, which helps maintain Fe homeostasis by regulating the level of the transcription factor Fur. To gain a more comprehensive insight into the physiological roles of FtsH hetero-complexes, we performed genome-wide expression profiling and global proteomic analyses of Synechocystis mutants conditionally depleted of FtsH3 or FtsH1 grown under various nutrient conditions. We show that the lack of FtsH1/3 leads to a drastic reduction in the transcriptional response to nutrient stress of not only Fur but also the Pho, NdhR, and NtcA regulons. In addition, this effect is accompanied by the accumulation of the respective transcription factors. Thus, the FtsH1/3 complex is of critical importance for acclimation to iron, phosphate, carbon, and nitrogen starvation in Synechocystis.plantcell;31/12/2912/FX1F1fx1.
- MeSH
- aklimatizace genetika MeSH
- bakteriální proteiny genetika metabolismus MeSH
- dusík nedostatek metabolismus MeSH
- exprese genu MeSH
- fosfáty nedostatek metabolismus MeSH
- fosforylace MeSH
- fotosystém II (proteinový komplex) chemie genetika metabolismus MeSH
- metaloproteasy genetika metabolismus MeSH
- mutace MeSH
- proteiny vázající fosfáty genetika metabolismus MeSH
- proteolýza MeSH
- proteom genetika metabolismus MeSH
- proteomika MeSH
- regulace genové exprese u bakterií genetika MeSH
- regulon genetika MeSH
- represorové proteiny genetika metabolismus MeSH
- ribozomální proteiny genetika metabolismus MeSH
- Synechocystis enzymologie metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- uhlík nedostatek metabolismus MeSH
- živiny nedostatek metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
... Takes Place 379 -- I Light Microscopy: Visualizing Cell Structure and Localizing Proteins Within Cells ... ... Complexes Increase the Efficiency of Photosynthesis 515 -- I Molecular Analysis of Photosystems 517 ... ... and Light-Absorbing Pigments 511 -- Thylakoid Membranes in Chloroplasts Are the Sites of Photosynthesis ... ... in Plants 511 -- Three of the Four Stages in Photosynthesis Occur -- Only During Illumination 511 -- ... ... Each Photon of Light Has a Defined Amount of Energy 513 -- Photosystems Comprise a Reaction Center and ...
6th ed. xxxvii, 1150 s. : il., tab. ; 29 cm
- MeSH
- biologie buňky MeSH
- molekulární biologie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biologie
- cytologie, klinická cytologie
... Set of Proteins, Revealing That Much Remains Unknown 122 -- Larger Protein Molecules Often Contain More ... ... - The Cell Regulates the Catalytic Activities of Its Enzymes 149 -- Allosteric Enzymes Have Two or More ... ... MICROSCOPE 529 -- The Light Microscope Can Resolve Details 0.2 (im Apart 530 -- Photon Noise Creates ... ... Additional Limits to Resolution When -- Light Levels Are Low 532 -- Living Cells Are Seen Clearly in ... ... \'\"Thetic Electron-Transport Chains of Cyanobacteria -mospheric Oxygen and Permitted New -- SYSTEMS ...
Sixth edition xxxiv, 1430 stran v různém stránkování : ilustrace (převážně barevné) ; 29 cm
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- molekulární biologie, molekulární medicína
- NLK Publikační typ
- učebnice vysokých škol
... that Fluoresce 49 -- The Electron Microscope Can Resolve Objects a Thousand Times Better than the Light ... ... the Cleaners 115 -- Glucose Degradation Yields Energy and Reducing Power, Which Cells Use to Make More ... ... Overcome by an Inducible Enzyme System of DNA Replication that Makes Many Mistakes 160 -- Visible Light ... ... without Releasing Oxygen 250 -- Oxygenic Photosynthetic Bacteria Liberate Oxygen as a By-product of ... ... Their Photosynthesis 251 -- Budding and/or Appendaged Bacteria Are Characterized by Cytoplasm-filled ...
XXVIII, 812 s. : il. ; 32 cm
