Physiological role of nickel and its toxic effects on higher plants

Uncoupling proteins, members of the mitochondrial carrier family, are present in mitochondrial inner membrane and mediate free fatty acid-activated, purine-nucleotide-inhibited H+ re-uptake. Since 1995, it has been shown that the uncoupling protein is present in many higher plants and some microorganisms like non-photosynthetic amoeboid protozoon, Acanthamoeba castellanii and non-fermentative yeast Candida parapsilosis. In mitochondria of these organisms, uncoupling protein activity is revealed not only by stimulation of state 4 respiration by free fatty acids accompanied by decrease in membrane potential (these effects being partially released by ATP and GTP) but mainly by lowering ADP/O ratio during state 3 respiration. Plant and microorganism uncoupling proteins are able to divert very efficiently energy from oxidative phosphorylation, competing for deltamicroH+ with ATP synthase. Functional connection and physiological role of uncoupling protein and alternative oxidase, two main energy-dissipating systems in plant-type mitochondria, are discussed.

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High Purity cis-Cinnamic Acid Preparation for Studying Physiological Role of trans-Cinnamic and cis-Cinnamic Acids in Higher Plants

Environment Control in Biology ◽

10.2525/ecb.51.1 ◽

2013 ◽

Vol 51 (1) ◽

pp. 1-10 ◽

Cited By ~ 9

Author(s):

Mar^|^iacute;a Laura SALUM ◽

Rosa ERRA-BALSELLS

Keyword(s):

Cinnamic Acid ◽

High Purity ◽

Higher Plants ◽

Physiological Role ◽

Cinnamic Acids

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Function and toxicity of amyloid beta and recent therapeutic interventions targeting amyloid beta in Alzheimer's disease

Chemical Communications ◽

10.1039/c5cc05264e ◽

2015 ◽

Vol 51 (70) ◽

pp. 13434-13450 ◽

Cited By ~ 99

Author(s):

K. Rajasekhar ◽

Malabika Chakrabarti ◽

T. Govindaraju

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Beta ◽

Physiological Role ◽

Therapeutic Interventions ◽

Toxic Effects ◽

Feature Article ◽

Therapeutic Molecules

Our Feature Article details the physiological role of amyloid beta (Aβ), elaborates its toxic effects and outlines therapeutic molecules designed in the last two years targeting different aspects of Aβ for preventing AD.

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1004 THE DUAL ROLE OF MANNITOL AS OSMOPROTECTANT AND PHOTOASSIMILATE IN CELERY

HortScience ◽

10.21273/hortsci.29.5.573d ◽

1994 ◽

Vol 29 (5) ◽

pp. 573d-573

Author(s):

D.M. Pharr ◽

J.M.H. Stoop ◽

M.E. Studer Feusi ◽

J.D. Williamson ◽

M.O. Massel ◽

...

Keyword(s):

Culture Medium ◽

Higher Plants ◽

Physiological Role ◽

Salt Tolerant ◽

Mannitol Dehydrogenase ◽

Molecular Control ◽

Compatible Osmolyte ◽

Mannitol Concentration ◽

Control Of Expression

Mannitol, a six carbon sugar alcohol, is widely distributed in nature and is a major phloem-translocated photoassimilate in celery. II may also function as a compatible osmolyte providing stress tolerance. Until recently, little was known about the route of mannitol catabolism in sink tissues of higher plants. An enzyme. mannitol dehydrogenase. (MDH) that oxidizes mannitol to mannose utilizing NAD as the electron acceptor was discovered (Arch. Biochem. Biophys. 1991. 298:612-619) in “sink” tissues of celery and celeriac plants. The activity of the enzyme is inversely related to tissue mannitol concentration in various parts of celery plants suggesting a role for the enzyme in mannitol catabolism. In osmostressed celery plants, the activity of the enzyme in sink tissues decreases as mannitol accumulates. Celery cells growing heterotrophically in suspension culture utilize either sucrose or mannitol as the sole carbon source and grow equally well on either carbohydrate. Mannitol-grown cells contain more MDI-I activity than sucrose-grown cells, and the activity of the enzyme is correlated with the rate of depletion of mannitol from the culture medium. Cells growing on mannitol contain an internal pool of mannitol but little sugar. Cells growing on sucrose contain internal sugar pools but no mannitol. Mannitol-grown cells are also more salt tolerant than cells grown on sucrose. Our laboratory is involved in studies of the physiological role of the mannitol oxidizing enzyme in regulating mannitol utilization and the role of the enzyme in regulating mannitol pool size during salt and osmostress in both celery plants and celery suspension cultures. Current studies on the molecular control of expression of the enzyme will be discussed.

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Alternative oxidase in higher plants.

Acta Biochimica Polonica ◽

10.18388/abp.2003_3649 ◽

2003 ◽

Vol 50 (4) ◽

pp. 1257-1271 ◽

Cited By ~ 68

Author(s):

Izabela M Juszczuk ◽

Anna M Rychter

Keyword(s):

Gene Expression ◽

Alternative Oxidase ◽

Higher Plants ◽

Experimental Studies ◽

Physiological Role ◽

Specific Gene ◽

Stressful Environment ◽

Cytochrome Pathway ◽

Flow Through

Plant respiratory chain branches at the level of ubiquinone from where the electrons flow through the cytochrome pathway or to alternative oxidase. Transfer of electrons from ubiquinone to oxygen by alternative oxidase has a non-protonmotive character and, by bypassing two sites of H+ pumping in complexes III and IV, lowers the energy efficiency of respiration. In this paper we review theoretical and experimental studies about the structure and possible function of alternative oxidase. The evidence for specific gene expression dependent on the physiological, developmental and environmental conditions is also described. We underline the physiological role of alternative oxidase as a "survival" protein that allows plants to cope with the stressful environment.

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