Vesicular Monoamine Transport Inhibitors

Effects of three diphenylether herbicides [2,4-dichlorophenyl-p-nitrophenyl ether (nitrofen); 2,4,6-trichlorophenyl-4′-nitrophenyl ether (hereinafter referred to as MC-1478); and 2,4′-dinitro-4-trifluoromethyl-diphenylether (hereinafter referred to as C-6989)] were measured on phosphorylation and electron transport in spinach(Spinacia oleraceaL.) chloroplasts, and mung bean(Phaseolus aureusL., var. Jumbo) and white potato tuber(Solarium tuberosumL.) mitochondria. All of the diphenylethers acted primarily as inhibitors of chloroplast noncyclic electron transport, and the coupled photophosphorylation. The compounds ranked in the following decreasing order of inhibitory effectiveness: MC-1478 ≥ C-6989 >> nitrofen. A site of action close to light reaction II was suggested. At high molar concentrations, marginal interference with cyclic electron transport or phosphorylation was obtained. In mitochondria, MC-1478 and nitrofen acted primarily as electron transport inhibitors with malate, NADH, and succinate as substrates. MC-1478 was a slightly stronger inhibitor than nitrofen. Only slight stimulation of ADP-limited oxygen uptake was obtained during the oxidation of NADH and succinate; whereas, strong inhibition of oxygen uptake was obtained with malate. C-6989 also weakly stimulated ADP-limited oxygen uptake with NADH and succinate but differed from the two chlorinated diphenylethers in that electron transport was not inhibited when ADP was present in excess. Interference with ATP generation could be one of the mechanisms through which the phytotoxicity of diphenylether herbicides is expressed.

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Assessing Vesicular Monoamine Transport and Toxicity Using Fluorescent False Neurotransmitters

Chemical Research in Toxicology ◽

10.1021/acs.chemrestox.0c00380 ◽

2020 ◽

Author(s):

Carlie A. Black ◽

Meghan L. Bucher ◽

Joshua M. Bradner ◽

Lauren Jonas ◽

Kenny Igarza ◽

...

Keyword(s):

Monoamine Transport

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Replacement of photosynthetic electron transport inhibitors by silicomolybdate

Physiologia Plantarum ◽

10.1111/j.1399-3054.1982.tb06329.x ◽

1982 ◽

Vol 54 (2) ◽

pp. 221-224 ◽

Cited By ~ 9

Author(s):

Peter Boger

Keyword(s):

Electron Transport ◽

Photosynthetic Electron Transport ◽

Transport Inhibitors

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Attenuation of GARP expression on regulatory T cells by protein transport inhibitors

Journal of Immunological Methods ◽

10.1016/j.jim.2021.112998 ◽

2021 ◽

Vol 492 ◽

pp. 112998

Author(s):

Sara Anvari ◽

Kimberly Schuster ◽

Andrea Grimbergen ◽

Carla M. Davis ◽

George Makedonas

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Protein Transport ◽

Transport Inhibitors

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Sites of Herbicidal Action on Photosynthesis: A Fluorescence Assay Study

Weed Science ◽

10.1017/s0043174500039813 ◽

1981 ◽

Vol 29 (4) ◽

pp. 371-375 ◽

Cited By ~ 8

Author(s):

H. Böhme ◽

K. J. Kunert ◽

P. Böger

Keyword(s):

Chlorophyll Fluorescence ◽

Membrane Lipids ◽

Diphenyl Ether ◽

Algal Growth ◽

Fluorescence Induction ◽

Rapid Screening ◽

Diphenyl Ethers ◽

Total Fluorescence ◽

Transport Inhibitors ◽

Weak Electron

The effect of the bleaching and non-bleaching phenylpyridazinones, norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone] and BAS 29095 [4,5-dimethoxy-2-phenyl-3(2H)-pyridazinone], on chlorophyll fluorescence of the green alga,Scenedesmus acutus, was investigated and compared to other bleaching herbicides, difunon3[EMD-IT 5914, 5(dimethylamino-methylene)-2-oxo-4-phenyl-2,5-dihydrofuranecarbonitrile-(3)] and the diphenyl ether, oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene]. Following chlorophyll fluorescence during short-term cultivation in the presence of herbicides and comparing it to physiological parameters such as chlorophyll content and packed cell volume allowed for rapid screening to detect different primary herbicidal modes of action. Two primary bleaching effects caused by either inhibition of carotene biosynthesis (certain substituted pyridazinones and difunon) or peroxidative degradation of membrane lipids (certain diphenyl ethers) led to completely different fluorescence signals. Growth of algae in the presence of a carotene biosynthesis inhibitor resulted in a rapid rise to maximum fluorescence, followed by a single decay phase, whereas bleaching diphenyl ethers led to a rapid loss of total fluorescence. Non-bleaching phenylpyridazinones, which act as weak electron transport inhibitors, inhibited variable fluorescence. Detoxication during algal growth became evident by recovery of the fluorescence induction.

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