Recovery of plastids from photooxidative damage: Significance of a plastidic factor

Planta ◽  
1988 ◽  
Vol 174 (3) ◽  
pp. 289-297 ◽  
Author(s):  
C. Schuster ◽  
R. Oelm�ller ◽  
R. Bergfeld ◽  
H. Mohr
Keyword(s):  
Photooxidative Damage ◽  
Plastidic Factor

scholarly journals Photooxidative Damage of Plants

1985 ◽  
Vol 10 (4) ◽  
pp. 729-743 ◽  
Author(s):  
Kozi ASADA
Keyword(s):  
Photooxidative Damage

scholarly journals Sunlight Inactivation of Fecal Indicator Bacteria and Bacteriophages from Waste Stabilization Pond Effluent in Fresh and Saline Waters

2002 ◽  
Vol 68 (3) ◽  
pp. 1122-1131 ◽  
Author(s):  
Lester W. Sinton ◽  
Carollyn H. Hall ◽  
Philippa A. Lynch ◽  
Robert J. Davies-Colley
Keyword(s):  
River Water ◽  
Fecal Coliform ◽  
Natural Waters ◽  
Fecal Coliforms ◽  
Somatic Coliphages ◽  
Stabilization Pond ◽  
Waste Stabilization Pond ◽  
Waste Stabilization ◽  
Photooxidative Damage ◽  
Wide Range

ABSTRACT Sunlight inactivation in fresh (river) water of fecal coliforms, enterococci, Escherichia coli, somatic coliphages, and F-RNA phages from waste stabilization pond (WSP) effluent was compared. Ten experiments were conducted outdoors in 300-liter chambers, held at 14°C (mean river water temperature). Sunlight inactivation (k S) rates, as a function of cumulative global solar radiation (insolation), were all more than 10 times higher than the corresponding dark inactivation (k D) rates in enclosed (control) chambers. The overall k S ranking (from greatest to least inactivation) was as follows: enterococci > fecal coliforms ≥ E. coli > somatic coliphages > F-RNA phages. In winter, fecal coliform and enterococci inactivation rates were similar but, in summer, enterococci were inactivated far more rapidly. In four experiments that included freshwater-raw sewage mixtures, enterococci survived longer than fecal coliforms (a pattern opposite to that observed with the WSP effluent), but there was little difference in phage inactivation between effluents. In two experiments which included simulated estuarine water and seawater, sunlight inactivation of all of the indicators increased with increasing salinity. Inactivation rates in freshwater, as seen under different optical filters, decreased with the increase in the spectral cutoff (50% light transmission) wavelength. The enterococci and F-RNA phages were inactivated by a wide range of wavelengths, suggesting photooxidative damage. Inactivation of fecal coliforms and somatic coliphages was mainly by shorter (UV-B) wavelengths, a result consistent with photobiological damage. Fecal coliform repair mechanisms appear to be activated in WSPs, and the surviving cells exhibit greater sunlight resistance in natural waters than those from raw sewage. In contrast, enterococci appear to suffer photooxidative damage in WSPs, rendering them susceptible to further photooxidative damage after discharge. This suggests that they are unsuitable as indicators of WSP effluent discharges to natural waters. Although somatic coliphages are more sunlight resistant than the other indicators in seawater, F-RNA phages are the most resistant in freshwater, where they may thus better represent enteric virus survival.

scholarly journals A thylakoid membrane-bound and redox-active rubredoxin (RBD1) functions in de novo assembly and repair of photosystem II

2019 ◽  
Vol 116 (33) ◽  
pp. 16631-16640 ◽  
Author(s):  
José G. García-Cerdán ◽  
Ariel L. Furst ◽  
Kent L. McDonald ◽  
Danja Schünemann ◽  
Matthew B. Francis ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Thylakoid Membrane ◽  
De Novo Assembly ◽  
Biochemical Characterization ◽  
De Novo ◽  
Midpoint Potential ◽  
Photosynthetic Organisms ◽  
Redox Active ◽  
Photooxidative Damage

Photosystem II (PSII) undergoes frequent photooxidative damage that, if not repaired, impairs photosynthetic activity and growth. How photosynthetic organisms protect vulnerable PSII intermediate complexes during de novo assembly and repair remains poorly understood. Here, we report the genetic and biochemical characterization of chloroplast-located rubredoxin 1 (RBD1), a PSII assembly factor containing a redox-active rubredoxin domain and a single C-terminal transmembrane α-helix (TMH) domain. RBD1 is an integral thylakoid membrane protein that is enriched in stroma lamellae fractions with the rubredoxin domain exposed on the stromal side. RBD1 also interacts with PSII intermediate complexes containing cytochrome b559. Complementation of the Chlamydomonas reinhardtii (hereafter Chlamydomonas) RBD1-deficient 2pac mutant with constructs encoding RBD1 protein truncations and site-directed mutations demonstrated that the TMH domain is essential for de novo PSII assembly, whereas the rubredoxin domain is involved in PSII repair. The rubredoxin domain exhibits a redox midpoint potential of +114 mV and is proficient in 1-electron transfers to a surrogate cytochrome c in vitro. Reduction of oxidized RBD1 is NADPH dependent and can be mediated by ferredoxin-NADP+ reductase (FNR) in vitro. We propose that RBD1 participates, together with the cytochrome b559, in the protection of PSII intermediate complexes from photooxidative damage during de novo assembly and repair. This role of RBD1 is consistent with its evolutionary conservation among photosynthetic organisms and the fact that it is essential in photosynthetic eukaryotes.

Photooxidative damage to the cyanobacterium Spirulina platensis mediated by singlet oxygen

1995 ◽  
Vol 31 (1) ◽  
pp. 44-48 ◽  
Author(s):  
D. P. Singh ◽  
Neeraj Singh ◽  
Kavita Verma
Keyword(s):  
Singlet Oxygen ◽  
Spirulina Platensis ◽  
Photooxidative Damage

scholarly journals Colorful World of Microbes: Carotenoids and Their Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Kushwaha Kirti ◽  
Saini Amita ◽  
Saraswat Priti ◽  
Agarwal Mukesh Kumar ◽  
Saxena Jyoti
Keyword(s):  
Disease Control ◽  
Antimicrobial Agents ◽  
Industrial Applications ◽  
Culture Conditions ◽  
Biosynthetic Pathways ◽  
Microbial Cells ◽  
Naturally Occurring ◽  
Photooxidative Damage ◽  
Food And Nutrition ◽  
Yellow Orange

Microbial cells accumulate pigments under certain culture conditions, which have very important industrial applications. Microorganisms can serve as sources of carotenoids, the most widespread group of naturally occurring pigments. More than 750 structurally different yellow, orange, and red colored molecules are found in both eukaryotes and prokaryotes with an estimated market of $ 919 million by 2015. Carotenoids protect cells against photooxidative damage and hence found important applications in environment, food and nutrition, disease control, and as potent antimicrobial agents. In addition to many research advances, this paper reviews concerns with recent evaluations, applications of microbial pigments, and recommendations for future researches with an understanding of evolution and biosynthetic pathways along with other relevant aspects.

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