Cell membrane complex

Liposomes made from pure phosphatidylcholine or containing lipids that are found in the cell membrane complex of wool (e.g. cholesterol) have been used to encapsulate aqueous chlorine solutions in chlorination processes [61,62]. The results showed improvements in... 

Exploration of the use of liposomes in wool processing stems from the similarity that exists between the bilayer structure of the cell membrane complex of wool and that of the liposomes. Merino wool contains about 1% by weight of lipids, these forming the hydrophobic barrier of the cell membrane complex. Cholesterol is one of the main lipid... 

Both the cuticle and cortical cells are bounded by cell membranes that, together with the intercellular material, are known as the cell membrane complex (Marshall, Orwin, and Gillespie 1991). This consists of the (Mayers, protein-lipid complexes (-5 nm thick) on either side of the 6-layer, and an intercellular cement (-15 nm thick) (Baden 1990) rich in amino and carboxyl... 

Allen, A. K., Ellis, J., and Rivett, D. E. (1991). The presence of glycoproteins in the cell membrane complex of a variety of keratin fibres. Biochim. Biophys. Acta 1074, 331-333. 

The structure, organization, and ratio of matrix and fibrous proteins contribute to the physiochemical properties of keratinous tissues. For example, a primary difference between hair and nails is the arrangement of fibrous proteins and the concentration of matrix proteins present in each tissue. In cells destined to form the cortex of hair, fibrous proteins are oriented to form filaments which cluster to form fibrils. In the keratogenous zone, fibrils undergo lateral fusion to ultimately produce the cortex. The medulla also contains keratin which has been characterized as a collection of irregular fibrous proteins. Fibrous proteins form a trabecular framework comprising 95% of the medulla, and medullary proteins are less resistant to chemical degradation than proteins in the cortex. The cell membrane complex. 

The two major morphological parts in the structure of wool are cuticle and cortex. The epi-cuticle of wool fibres surrounds each cuticle, it consists of approximately one-quarter fatty acid and three-quarters protein by mass. The hydrophobic epiCLiticle acts as a barrier to dyes which enter the wool fibre between cuticle cells through the highly cross-linked cell membrane complex (CMC). Enzyme from the liquor can diffuse into the interior of the fibre and hydrolyse parts of the endocuticle and proteins in the cell membrane complex, completely damaging the fibre if not controlled. In contrast, the catalytic action of enzyme on cotton is confined to the surface and the amorphous region only. 

An important component of the cuticle structure is the cell membrane complex, or CMC, which consists of a (8) proteinaceous layer, sandwiched by two (fJ>) lipid layers. The CMC is the only continuous structure in hair. It acts as a cement between different layers or components of the hair fiber and is responsible for the physical integrity of the hair structure. 

Recently, there has been increasing evidence that interior lipid material, much of which is structural, can be removed by shampooing [202,206], The internal lipids removed over time by repeated shampooing are most likely from the inert ( 3) layers of the cell membrane complex which is the major pathway for entry of surfactants into the fibers. 

Like most bacteria, the Microtox strain has many metabolic pathways which function in respiration, oxidative phosphorylation, osmotic stabilization, and transport of chemicals and nutrients into and out of the cell, and which are located within or near the cytoplasmic membrane. The luciferase pathway [9], which functions as a shunt for electrons directly to oxygen at the level of reduced flavin mono-nucleotide, is also located within the cell membrane complex. This, coupled with lack of membrane-aided compartmentalization of internal functions, gives many target sites at or near the cytoplasmic membrane. These factors all contribute to a rapid response of the organisms to a broad spectrum of toxic substances. 

Figure 1-23. Schematic illustrating cell membrane complex in animal hairs (from Fraser et al. [68]).

Cell membrane complex is the material that binds or holds the cells together... 

The cell membrane complex and the endoctitide are the most vulnerable to the attack by shampoos, to build-up and even to stretching and cracking. If build-up gets beneath the scales, it can cause scale lifting a type of scale damage that makes the hair feel dry, coarse and look dull... 

The cortex constitutes the major part of the fiber mass of human hair and consists of cells and intercellular binding material. The intercellular binding material, or the cell membrane complex, is described later in this chapter. 

Swift, therefore, proposed that the difference can be explained by the large-order swelling that occurs in the nonkeratin regions of the cuticle and the cortex, primarily the cell membrane complex and the endocuticle (Figure 1-40). 

Medullary cells are loosely packed, and during dehydration (formation), they leave a series of vacuoles along the fiber axis. Medullary cells are spherical and hollow inside and are bound together by a cell membrane complex type material (see Figure 1-43). Because the medulla is believed to contribute negligibly to the chemical and mechanical properties of human hair fibers [131] and is difficult to isolate [122,134], it has received comparatively little scientific attention. The chemical composition of medullary protein derived from African porcupine quill has been reported by Rogers [118] and is described in Chapter 2. 

The structure and degradation of the cell membrane complex including the structure of the epicuticle. 

A proteinaceous substance called epicuticle has been isolated from wool fiber by Golden et al. [73], The protein portion of this cell membrane complex material was found to be rich in the dicarboxylic amino acids, aspartic acid, and glutamic acid. 

Holmes [74] has isolated a fatty-acid protein complex from human hair that appears to protect the hair during papain digestion (cell membrane complex). Analysis of this complex indicates 20 to 30% fatty acid (lipid material) and 60 to 70% protein, rich in the amino acid lysine. Holmes suggests that this substance is either epicuticle or a fraction of the epicuticle. To avoid confusion, this material should be called either cell membrane complex or a portion of the cell membrane complex, which consists of protein and lipid components. 

The cell membrane complex is described in schematic form in Chapter... 

The inert beta layers of the cell membrane complex are Upid-protein-type structures [78]. Sakamoto et al. [83] claim that fatty acids and wax esters are the main components of the internal lipids of human hair. Hilter-haus-Bong and Zahn [84] also find fatty acids, cholesteryl esters, and wax esters as main components however, they find polar lipids as major components. The fatty acids of this important component of human hair are predominately palmitic, stearic, and oleic acids. 

Lipid extracted from human hair is similar in composition to scalp lipid [134]. Thus, the bulk of the extractable lipid in hair is free lipid however, cell membrane complex lipid is also partially removed by extraction of hair with lipid solvents or surfactants. In a sense, the scalp serves as a lipid supply system for the hair, with sebum being produced continuously by the sebaceous glands [135]. Sebum production is controlled hormonally by androgens that increase cell proliferation in the sebaceous glands, and this in turn increases sebum production [135,136], although seasonal and even daily variations in the rate of sebum production do occur [137]. 

Figure 3-3. Fiber was oxidized, reduced, and then extended to fracture in the dry state. This scanning electron micrograph was taken at the fracture site. Note the multiple-step fractures and that much of the fracturing occurs in the cell membrane complex. SEM kindly provided by Sigrid Ruetsch of Textile Research Institute/ Princeton.

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