Section 7
Chapter 6,823

Trans plasma membrane electron transport in anacystis nidulans

Craig, T.A.; Crane, F.L.; Misra, P.C.; Barr, R.

Plant Science Letters 35(1): 11-18


DOI: 10.1016/0304-4211(84)90151-2
Accession: 006822292

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Ferricyanide is reduced in the dark by whole cells of A. nidulans. A transmembrane redox system spanning the plasma membrane of these cells is proposed to be the mechanism involved in external ferricyanide reduction by these cells. Ferricyanide reduction is not due to the excretion of reductants, as indicated by a low rate of ferricyanide reduction in the supernatant after removal of cells. Low rates of cytochrome c reduction compared to ferricyanide indicate ferricyanide reduction is not due to release of low potential reducing agents. Catechol release by these cells in minimal. The ferricyanide is not reduced after entry into cells since ferricyanide is recovered in the suspension media. Lack of inhibition by sulfhydryl reagents indicated that the excretion of sulfhydryl reductants or the presence of sulfhydryl sites on the membrane are not causing external ferricyanide reduction. No ferricyanide oxidation by whole cells of A. nidulans was detected. Inhibition of O2-uptake by ferricyanide suggests that a plasma membrane respiratory system may be partially involved. Stimulation of the rate of ferricyanide reduction by 2-n-heptyl-4-hydroxy-quinoline-N-oxide (HOQNO) is a further indication of the selective involvement of the plasma membrane respiratory chain in the external ferricyanide reduction by A. nidulans.

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