Cuticular

The surface of the green coffee contains a cuticular wax layer (0.2—0.3% db) for both varieties. The wax contains insoluble hydroxytryptamides derived from 5-hydroxytryptamine [61 7-2] and saturated C18—C22 fatty acids. 

Hurst (19) discusses the similarity in action of the pyrethrins and of DDT as indicated by a dispersant action on the lipids of insect cuticle and internal tissue. He has developed an elaborate theory of contact insecticidal action but provides no experimental data. Hurst believes that the susceptibility to insecticides depends partially on the cuticular permeability, but more fundamentally on the effects on internal tissue receptors which control oxidative metabolism or oxidative enzyme systems. The access of pyrethrins to insects, for example, is facilitated by adsorption and storage in the lipophilic layers of the epicuticle. The epicuticle is to be regarded as a lipoprotein mosaic consisting of alternating patches of lipid and protein receptors which are sites of oxidase activity. Such a condition exists in both the hydrophilic type of cuticle found in larvae of Calliphora and Phormia and in the waxy cuticle of Tenebrio larvae. Hurst explains pyrethrinization as a preliminary narcosis or knockdown phase in which oxidase action is blocked by adsorption of the insecticide on the lipoprotein tissue components, followed by death when further dispersant action of the insecticide results in an irreversible increase in the phenoloxidase activity as a result of the displacement of protective lipids. This increase in phenoloxidase activity is accompanied by the accumulation of toxic quinoid metabolites in the blood and tissues—for example, O-quinones which would block substrate access to normal enzyme systems. The varying degrees of susceptibility shown by different insect species to an insecticide may be explainable not only in terms of differences in cuticle make-up but also as internal factors associated with the stability of oxidase systems. 

Cutinase is a hydrolytic enzyme that degrades cutin, the cuticular polymer of higher plants [4], Unlike the oflier lipolytic enzymes, such lipases and esterases, cutinase does not require interfacial activation for substrate binding and activity. Cutinases have been largely exploited for esterification and transesterification in chemical synthesis [5] and have also been applied in laundry or dishwashing detergent [6]. 

A sequence of reptilian studies tracked down the likely signal for mating in Canadian Red-sided Garter snakes. Males respond to products on the female s skin surface, which turn out to be related both to insect cuticular lipids and to those of mammalian skin. These integumentary... 

Consistent with the definition of terms adopted for the discussion in this series of papers of integral phases of the residue studies being conducted by the Division of Entomology, University of California Citrus Experiment Station (2, 13-15), the following distinctions are noted Residues may be specified as pretreatment, posttreatment, harvest, or ultimate. The latter refers to the residue on or in foodstuffs, whether fresh or processed, at the time of consumption (2, 13). The location of residues with reference to fruit parts may be extra-surface (external to the cuticle) or subsurface. Subsurface residues may be differentiated with reference to actual location as cuticular residues or specified intracarp residues. Residues in the cuticular layers or in any of the cellular structures or matrices are herein indicated as subsurface (penetrated) residues (2, 13). 

It would seem, therefore, that particularly with oil- and wax-soluble insecticides the older concepts of surface residues on plant tissues should be revised in terms of extrasurface—i.e., above the cuticle—and subsurface—i.e., within or below the cuticle— residues. The latter would in turn be subdivided into cuticular residues and various intracarp residues. 

Enzymes can be used to modify the surface of wool fibres in order to improve lustre, softness, smoothness or warmth of the fabric. Since such processes involve attack on the cuticular scales of the fibre, there is clearly a resemblance to shrink-resist treatments and similar methods are used [116] ... 

Whilst elimination (by oxidation) or masking (by polymer deposition on the cuticular scales) are the accepted mechanisms by which shrink resistance is achieved, there is evidence that other factors need to be considered, particularly as it is possible to obtain a shrink-resist effect without degradation or masking of the scales. A review is available [310] of the mechanism of chlorine-based shrink-resist processes. 

Dawkins, H.J.S. and Spencer, T.L. (1989) The isolation of nucleic acid from nematodes requires an understanding of the parasite and its cuticular structure. Parasitology Today 5, 73-76. 

Bisoffi, M. and Betschart, B. (1996) Identification and sequence comparison of a cuticular collagen of Brugia pahangi. Parasitobgy 113, 145-155. 

Cookson, E., Blaxter, M. and Selkirk, M. (1992) Identification of the major soluble cuticular glycoprotein of lymphatic filarial nematode parasites (gp29) as a secretory homolog of glutathione-peroxidase. Proceedings of the National Academy of Sciences USA 89, 5837-5841. 

Fetterer, R.H., Rhoads, M.L. and Urban, J.F. (1993) Synthesis of tyrosine-derived cross-links in Ascaris suum cuticular proteins. Journal of Parasitology 79,160-166. 

Johnstone, I.L., Shaft, Y., Majeed, A. and Barry, J.D. (1996) Cuticular collagen genes from the parasitic nematode Ostertagia drcumcincta. Molecular and Biochemical Parasitology 80, 103-112. 

Selkirk, M.E., Nielsen, L., Kelly, C., Partono, F., Sayers, G. and Maizels, R.M. (1989) Identification, synthesis and immunogenicity of cuticular collagens from the filarial nematodes Brugia malayi and Brugia pahangi. Mokcular and Biochemical Parasitology 32, 229—246. 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

Fig. 17.2. (Opposite) Immuno-gold localization of a T. muris-derived IFN-y homologue to the bacillary band and cuticular pore. (A) Transmission electron micrograph of bacillary band showing the pore chamber (PC), pore aperture (PA) and lamellar apparatus (LA) (x22,000). (B) High-power localization of antibody staining (black dots) to the lamellar apparatus (LA) and pore chamber (PC) (x36,000). (Courtesy ofF. Bughdadi.)...

Pritchard, D.I., Quinnell, R.J., Slater, A.F.G., McKean, P.G., Dale, D.D.S., Raiko, A. and Keymer, A. (1990) Epidemiology and immunology of Necator americanus infection in a community in Papua New Guinea humoral responses to excretory-secretory and cuticular collagen antigens. Parasitology 100, 317-326. 

The site of pheromone production in flies and cockroaches that utilize hydrocarbons is similar to that of the moths. Oenocyte cells produce the hydrocarbon pheromone which is transported by lipophorin in the hemolymph to epidermal cells throughout the body for release from the cuticular surface in general [20,21]. 

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