Factors altering the membrane fluidity of spinach thylakoid as determined by fluorescence polarization

Abstract

Alterations in fluidity of thylakoid membranes isolated from spinach chloroplasts in response to sodium bisulfite (NaHSO 3 ), hydrogen peroxide (H 2 O 2 ), sodium dodecyl sulfate (SDS), bovine serum albumin (BSA), and free linoleic acid (LA) were investigated by means of a fluorescence polarization study with 1,6-diphenyl-1,3,5-hexatriene as the fluorescence probe. A decrease in fluidity and an increase in microviscosity of membrane were caused by NaHSO 3 and H 2 O 2 treatment. In contrast, SDS and BSA were found to increase thylakoid membranes fluidity and decrease microviscosity, in which the corresponding correlation coefficients were -0.9995 to -0.9516 (SDS) and -0.9359 (BSA), respectively. No changes in thylakoid membranes fluidity induced by free LA were found until its concentration above 5 mM where the polarization value (P value) declined (increased fluidity). The results suggest that the changes in thylakoids membrane fluidity might depend on the characteristics, mechanism and extent of the interactions between membrane components and compounds added.

A bioassay-guided fractionation system to identify endogenous small molecules that activate plasma membrane H+-ATPase activity in Arabidopsis

“…However, NaCl treatment reduced membrane fluidity. This result is consistent with the previous finding that C18:2 does not influence membrane fluidity ( Lin et al , 2011 ).…”

Polyprenols Are Synthesized by a Plastidial cis-Prenyltransferase and Influence Photosynthetic Performance

“…The apparently modest decrease in DPH fluorescence anisotropy (r) observed in polyprenol-deficient thylakoids indicates that polyprenols have an ordering effect on the thylakoid membrane bilayer. Such changes in DPH polarization are typically observed in vitro only when millimolar quantities of membranealtering agents, such as sterols, SDS, or benzyl alcohol are incorporated into model membrane systems (Yamamoto et al, 1981;Vigo et al, 1984;Popova and Hincha, 2007;Lin et al, 2011). Our observations with polyprenol-deficient thylakoids are therefore striking when considering that on a molar basis, polyprenol abundance in thylakoid membranes is approximately an order of magnitude lower than in the model membranes described above.…”

Methylation at the C-2 position of hopanoids increases rigidity in native bacterial membranes

“…Samples were incubated in a 25°C or 40°C water bath without light for 30 min, followed by measurements of fluorescence polarization (Fluorolog, HORIBA Instruments (Edison, NJ). Instrument parameter: ex 358 nm, slit = 3 mm; em 428 nm, slit = 7 mm; integration time = 1 s) ( Lin et al, 2011 ). Three biological replicates were measured, each containing 6–14 technical replicates.…”