Inhibition of Photosystem II in the Green Alga Scenedesmus obliquus by Nickel

El‐Sheekh, Mostafa M.

doi:10.1016/s0015-3796(11)80139-3

Cited by 20 publications

(12 citation statements)

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“…It was previously proposed that Ni 2+ inhibits PSII electron transport activity at the level of Q B (Mohanty et al 1989;El-Sheekh 1993) but at the same time, the quenching of variable Chl fluorescence following Ni 2+ treatment indicated an inhibition of oxygen evolution (Tripathy et al 1981;Mohanty et al 1989;El-Sheekh 1993). The data presented here using PSII preparations clearly demonstrate an inhibitory site for Ni 2+ at the OEC.…”

Section: Discussionsupporting

confidence: 65%

“…Previous reports indicated that relatively high concentrations of Ni 2+ (5-10 mM) produced a significant inhibitory effect in chloroplasts (Tripathy et al 1983;Mohanty et al 1989;Szalontai et al 1999) or in green alga (El-Sheekh 1993). In the green alga Haematococcus lacustris, 0.1 mM Ni 2+ already affected F v /F m measured at a Chl concentration of 15 mg Chl ml À1 but only after several days of exposure to the toxic cations (Xyländer and Braune 1994).…”

Section: Discussionmentioning

confidence: 89%

“…Most in vivo and in vitro studies indicated an inhibition of electron transport on the donor side of PSII that was illustrated by a decreased Chl fluorescence yield (Tripathy et al 1981;Mohanty et al 1989;). However, the inhibition in PSII was also discussed in terms of a modification of the binding site for Q B , the secondary quinone acceptor of PSII (Mohanty et al 1989;El-Sheekh 1993). The primary donor of PSII, P680, itself was also postulated as a direct target of Ni 2+ action (Tripathy et al 1981(Tripathy et al , 1983.…”

Section: Introductionmentioning

confidence: 99%

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Inhibition of the oxygen-evolving complex of photosystem II and depletion of extrinsic polypeptides by nickel

et al. 2007

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The toxic effect of Ni(2+) on photosynthetic electron transport was studied in a photosystem II submembrane fraction. It was shown that Ni(2+) strongly inhibits oxygen evolution in the millimolar range of concentration. The inhibition was insensitive to NaCl but significantly decreased in the presence of CaCl(2). Maximal chlorophyll fluorescence, together with variable fluorescence, maximal quantum yield of photosystem II, and flash-induced fluorescence decays were all significantly declined by Ni(2+). Further, the extrinsic polypeptides of 16 and 24 kDa associated with the oxygen-evolving complex of photosystem II were depleted following Ni(2+) treatment. It was deduced that interaction of Ni(2+) with these polypeptides caused a conformational change that induced their release together with Ca(2+) from the oxygen-evolving complex of photosystem II with consequent inhibition of the electron transport activity.

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Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Inhibition of the oxygen-evolving complex of photosystem II and depletion of extrinsic polypeptides by nickel

et al. 2007

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“…Bernier et al 1993) and steady-state chl fluorescence has been commonly observed as a consequence of heavy metal stress (e.g. Atal et al 1991;Bernier et al 1993;El-Sheekh 1993;Krupa et al 1993;Lanaras et al 1993;Lidon et al 1993;Ouzounidou 1993;Sgardelis et al 1994;Tripathy and Mohanty 1981), few authors have previously considered the possibility of using the decrease of steady state chl fluorescence as a parameter for the formation of Cu-chl (Küpper et al 1996;Wu and Lorenzen 1984). Also the changes of the other fluorescence kinetics parameters (F 0 , F m ) measured in copperstressed plants can be explained by a decrease in PS II antenna size caused by formation of non-fluorescent, inactive Cu-chl.…”

Section: Fluorescence Measurementsmentioning

confidence: 99%

Untitled

Küpper

Spiller

1998

Photosynthesis Research

272

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The in vivo substitution of magnesium, the central atom of chlorophyll, by heavy metals (mercury, copper, cadmium, nickel, zinc, lead) leads to a breakdown in photosynthesis and is an important damage mechanism in heavy metal-stressed plants. In this study, a number of methods are presented for the efficient in situ detection of this substitution (i.e. in whole plants or in chloroplasts). While macroscopic observations point to the formation of heavy metal chlorophylls at higher concentrations, fluorescence microscopy enables the detection of this reaction at very low substitution rates. Therefore, the course of the reaction can be followed by continuously measuring the fluorescence of whole plants. Furthermore absorbance spectroscopy of whole cells or isolated chloroplasts also enables the in situ detection of heavy metal chlorophylls. These methods provide practicable approaches in detecting the formation of these compounds in situ, avoiding artefacts that might occur using extraction methods based on polar solvents. In addition to the new methods for in situ detection, an extreme heterogeneity in the reaction of cells in the same tissue upon heavy metal stress was observed: while some cells are already disintegrating, others still show normal fluorescence and photosynthetic activity. Measurements of fluorescence kinetics gave a further hint that in high light intensity a substitution of Mg by heavy metals might take place specifically in PS II reaction centres.Abbreviations: chl -chlorophyll; DCMU -3-(3,4 Dichlorophenyl)-1,1-Dimethylurea; F 0 -basic ('dark') fluorescence; F m -maximum fluorescence; F v -variable fluorescence; F steadystate -steady state fluorescence, i.e. after fluorescence induction; hm 2+ -heavy metal 2+ ; hms -heavy metal-substituted; Mg-substitution -substitution of the natural central ion of chlorophyll, Mg 2+ , by heavy metals

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“…Heavy metal substitute chlorophylls and related porphyrins have been known in vitro for a long time (Kupper et al, 2000). Many researchers examined the effect of heavy metals on photosynthesis and observed a decrease in fluorescence (Atal et al, 1991;El-Sheekh, 1992). …”

Section: Issn: 2320-5407mentioning

confidence: 99%

An Assessment of Heavy Metal Accumulation Capacity of Five Aquatic Macrophytes and Biochemical Response.

KS¹,

Mathew²,

RameshBabuM³

2017

IJAR

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The phytoextraction capacity of five aquatic macrophytes (Eichhorniacrassipes,Hydrillaverticellata Pistia stratioties, Salviniamolesta and Lagenandra toxicaria) with respect to heavy metals like Ni, As, Zn, Cr and Fe were studied. It was done to study the plants capacity comparatively using monometallic system. Inorder to assess the biochemical response of the studied plants to heavy metal stress, metabolites like total carbohydrates, total soluble protein, tannin, total carotenoids, alkaloids, flavanoids, terpenoids, saponin and phenol were quantitatively estimated before and after treatment. With regard to Ni, As and Fe sample II showed maximum absorption and least by sample V. Zn absorption is greatest in plant sample II and least in sample I. As with Cr plant sample IV showed maximum absorption and least by sample I. The most significant biochemical change observed is the substantial increase in quantity of total carbohydrate, total soluble protein, total carotenoids, saponin and phenol content of the treated plants. Similarly there is a substantial reduction in metabolites like tannin, alkaloids, flavanoids and terpenoids after treatment. The studied macrophytes proved to the useful in the uptake of heavy metals in the monometallic system and showed great of potential for further applications in the industrial and waste water treatments.Copy Right, IJAR, 2017,. All rights reserved. …………………………………………………………………………………………………….... Introduction:-General contamination of heavy metals in the environment is a major global concern, which has provoked the emergence of phytpremediation technologies for cleaning aquatic environment. Heavy metals are released into the environment from a wide range of natural and anthropogenic sources. Aquatic systems often act as final receptacles to these metals whose concentration in interstitial water might increase several thousand folds by effluents from water (Bastian and Hammer 1993). Heavy metals are strong environmental pollutants and many of them are toxic, even at very low concentrations. Contrary to organic materials, they cannot be degraded and therefore they accumulate in water, bottom sediment and living organisms.Heavy metals are the stable metals or metalloids whose density is greater than 5g/cm3, namely mercury, cadmium, cobalt, lead, molybdenum, nickel, copper, zinc etc(Nies 1999). Heavy metals are natural constituents of the Earth's

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Inhibition of Photosystem II in the Green Alga Scenedesmus obliquus by Nickel

Cited by 20 publications

References 16 publications

Inhibition of the oxygen-evolving complex of photosystem II and depletion of extrinsic polypeptides by nickel

Inhibition of the oxygen-evolving complex of photosystem II and depletion of extrinsic polypeptides by nickel

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An Assessment of Heavy Metal Accumulation Capacity of Five Aquatic Macrophytes and Biochemical Response.

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