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Titolo:
Nitrogen starvation-induced chlorosis in Synechococcus PCC 7942. Low-levelphotosynthesis as a mechanism of long-term survival
Autore:
Sauer, J; Schreiber, U; Schmid, R; Volker, U; Forchhammer, K;
Indirizzi:
Univ Giessen, Inst Mikrobiol & Mol Biol, D-35392 Giessen, Germany Univ Giessen Giessen Germany D-35392 Mol Biol, D-35392 Giessen, Germany Univ Wurzburg, Lehrstuhl Bot 1, D-97082 Wurzburg, Germany Univ Wurzburg Wurzburg Germany D-97082 Bot 1, D-97082 Wurzburg, Germany Univ Osnabruck, Angew Mikrobiol Abt, Abt Mikrobiol, D-49069 Osnabruck, Germany Univ Osnabruck Osnabruck Germany D-49069 iol, D-49069 Osnabruck, Germany Univ Marburg, Mikrobiol Lab, D-35043 Marburg, Germany Univ Marburg Marburg Germany D-35043 obiol Lab, D-35043 Marburg, Germany Max Planck Inst Terr Mikrobiol, D-35043 Marburg, Germany Max Planck Inst Terr Mikrobiol Marburg Germany D-35043 Marburg, Germany
Titolo Testata:
PLANT PHYSIOLOGY
fascicolo: 1, volume: 126, anno: 2001,
pagine: 233 - 243
SICI:
0032-0889(200105)126:1<233:NSCISP>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
OUTER-MEMBRANE PROTEIN; SP STRAIN PCC-7942; GLUTAMINE-SYNTHETASE; CYANOBACTERIA; GENE; ELECTROPHORESIS; IDENTIFICATION; PURIFICATION; DEGRADATION; PCC-6301;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Forchhammer, K Univ Giessen, Inst Mikrobiol & Mol Biol, Heinrich Buff Ring26-32, D-35392Giessen, Germany Univ Giessen Heinrich Buff Ring 26-32 Giessen Germany D-35392
Citazione:
J. Sauer et al., "Nitrogen starvation-induced chlorosis in Synechococcus PCC 7942. Low-levelphotosynthesis as a mechanism of long-term survival", PLANT PHYSL, 126(1), 2001, pp. 233-243

Abstract

Cells of the non-diazotrophic cyanobacterium Synechococcus sp. strain PCC 7942 acclimate to nitrogen deprivation by differentiating into non-pigmented resting cells, which are able to survive prolonged periods of starvation. In this study, the physiological properties of the long-term nitrogen-starved cells are investigated in an attempt to elucidate the mechanisms of maintenance of viability. Preservation of energetic homeostasis is based on a low level of residual photosynthesis; activities of photosystem II and photosystem I were approximately 0.1% of activities of vegetatively growing cells. The low levels of photosystem I activity were measured by a novel colorimetric assay developed from the activity staining of ferredoxin:NADP(+) oxidoreductase. Photosystem II reaction centers, as determined by chlorophyllfluorescence measurements, exhibited normal properties, although the efficiency of light harvesting was significantly reduced compared with that of control cells. Long-term chlorotic cells carried out protein synthesis at a very low, but detectable level, as revealed by in vivo [S-35]methionine labeling and two-dimensional gel electrophoresis. Ln conjunction with the verylow levels of total cellular protein contents, this implies a continuous protein turnover during chlorosis. Synthesis of components of the photosynthetic apparatus could be detected, whereas factors of the translational machinery were stringently downregulated. Beyond the massive loss of protein during acclimation to nitrogen deprivation, two proteins that were identifiedas SomA and SomB accumulated due to an induced expression following nitrogen reduction.

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Documento generato il 27/11/20 alle ore 00:54:04