Lipid-Protein Microinclusions in the Morphological Structures of Organelle Membranes Studied by Fluorescent Confocal Microscopy

Abstract

Peculiar properties of morphological structures of organelle membranes were studied by fluorescent confocal microscopy. The list of objects in our experiments was represented by mitochondria, chloroplasts and vacuoles. During this study, identification of lipid microinclusions having the form of such lipid-protein structural microformations as lipid-protein microdomains, vesicles and membrane tubular structures (cytoplasmic transvacuolar strands and nanotubes) located in organelle membranes or bound up with them was conducted. Such membrane probes as laurdan, DPH, ANS and bis-ANS were used. Comparison of fluorescence intensity of these membrane probes was conducted. This investigation of the morphological properties of lipid-protein structural microformations was accompanied with analysis of 1) the phase state and 2) dynamics of microviscosity variations in the membrane elements of isolated plant cell organelles. Distributions of laurdan fluorescence generalized polarization (GP) values for the membrane on the whole and for the intensively fluorescing membrane segments were obtained. It was discovered that the microviscosity of intensively fluorescing membrane segments essentially differed from the microviscosity of the rest part of the membrane. In conclusion, some results of the study of peculiar properties of lipid-protein structural microformations related to the structure of organelle membranes and the discoveries made in this investigation are discussed. Keywords

Lipid Rafts and Plant Gravisensitivity

“…Because the Lo phase is characterized by a higher level of lipid packing compared to the Ld phase, it is also less hydrated and more viscous [92,93]. The difference in the CM water content can be estimated [94,95].…”

Detergent-Resistant Membranes in Chloroplasts and Mitochondria of the Halophyte Salicornia perennans under Salt Stress

“…DRMs were supposed to form so-called functional platforms, considered to be likely needed in the regulation of some special cellular functions [ 12 , 21 ]. DRMs interpreted as rafts were discussed as being involved in such cellular processes as signaling, trafficking [ 22 , 23 ] and regulatory processes [ 23 , 24 , 25 ], in the transport of nutrients [ 26 ] and in vesicular transport [ 4 ], etc.…”