Activities and stability of native and Triron X-100-fractionated thylakoid membranes from white spruce and spinach

Title:

Activities and stability of native and Triron X-100-fractionated thylakoid membranes from white spruce and spinach

Creator:

Rashid, Abdur and Camm, E.L.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:605ed2ba-2c58-4f3e-b042-2a681ccc071b
uuid:605ed2ba-2c58-4f3e-b042-2a681ccc071b
urnnbn:urn:nbn:cz:aba007-000foh

Subject:

chloroplast membrane, electron transport, oxygen evolving complex, photosystem 2, Picea glauca, Spinacia oleracea, and sucrose

Type:

model:internalpart and TEXT

Format:

print

Description:

From mature needles of white spruce, Picea glauca (Moench) Voss we isolated thylakoids capable of high rates of oxygen evolution. Oxygen-evolving activity of spruce thylakoids was labile in the absence of osmoticum and declined by 40 % during 1 h on ice, compared to a 9 % dechne observed in spinách thylakoids. We compared the relative activity in spruce and spinách of the oxygen evolving complex (OEC) and the reaction centre in Triton X-100 fractionated membranes prepared and stored for 20 or 240 h at 0 or -80 °C in media with different combinations of sucrose (0.3, 0.5 and 1.0 M) and two pH values (6.0 and 7.6). In membranes detergent- fractionated and stored at pH 7.6, photosystem 2 (PS2) activity (H2O -> DCIP) was sensitive to sucrose concentration of the medium. Spruce and spinách membranes prepared and stored in 0.3 M sucrose and pH 7.6, showed 22 and 48 % activity of their respective control membranes, freshly prepared in 1 M sucrose at pH 6.0. In contrast, in membranes prepared and stored at pH 6.0, PS2 activity was less sensitive to sucrose concentration: spruce and spinách membranes in 0.3 M sucrose showed 73 and 88 % (respectively) of the activity of membranes freshly prepared in 1 M sucrose. In both species, the degree of stimulation of DCIP photoreduction by diphenylcarbazide suggested minimal damage to the reaction centre (RC) except during preparation in 0.3 M sucrose, pH 7.6. Since the spruce RCs were not more labile than those of spinách, the extra sensitivity of spruce thylakoids in media of low sucrose concentration was likely due to extra lability of the OEC.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

389-398 and 71-80

Source:

Photosynthetica | 1995 Volume:31 | Number:3

Harvested from:

CDK

Metadata only:

false