Invertebral discs

Various miscellaneous applications of thermoanalytical techniques have included characterisation of albumins and their behaviour as fatty acids in the biosynthesis of lens lipids, while DSC has also provided on the age degeneration of human invertebral discs. 

Proteoglycans.— By using a vertical tube rotor for isopycnic centrifugation, the time taken for the isolation of proteoglycans from various tissues can be shortened and the resolution of proteoglycans is improved." Invertebral disc proteoglycans... 

Small angle X-ray- and neutron-diffraction patterns obtained for the annulus fibrosus of porcine invertebral disc have highlighted differences between the collagen in this tissue and that in tendon. ... 

Copper is toxic to sensitive species of terrestrial vegetation at >40 pg/L nutrient solution (seedlings of pines, Pirns spp.), at >10 mg/kg DW leaves (cucumber, Cucumis sativus), and >60 mg extractable Cu/kg DW soil (sweet orange, Citrus sinensis Table 3.4). Among sensitive species of terrestrial invertebrates, adverse effects on survival, growth, or reproduction occur at 2 pg Cu/cm2 on paper discs (earthworms), >50 mg Cu/kg diet (larvae of gypsy moth, Lymantria dispar), and 53 to 70 mg Cu/kg DW soil (earthworms and soil nematodes Table 3.4). 

Many starfish cause an escape response in usually sessile marine invertebrates [7]. The starfish Dermasterias imbricata causes the sea anemone Stomphia coccinea to release its basal disc from the substratum and swim away on contact. Bioassay-directed fractionation of the starfish extract led to the isolation of the compound found to elicit this response, the benzyltetrahydroisoquinoline alkaloid imbricatine (646). The structure of compound 646 was elucidated by spectral data interpretation. The amino acid residue in imbricatine is related to the thiol containing amino acids ovothiols A-C. Imbricatine (646) is active in both LI210 and P388... 

Contacts of another type, known as septate desmosomes or adhesion discs, form a belt around the cells of invertebrate epithelia. In these contacts a space of 18 nm between adjacent cell membranes is bridged in a number of places by thin walls. Behind the desmosomes the membrane is often backed up at these points by an electron-dense region to which are attached many fine microfilaments of -6-10 nm diameter (Fig. 1-15, D). 

Some details about cone cells and invertebrate vision. The biochemistry of retinal cones is less well known but is similar to that of rod cells. Cone pigments are present in the plasma membrane rather than in isolated discs (Fig. 23-40C). Different a, P, and y subunits of transducin are formed in rods and cones.522 Many differences are seen among various invertebrate visual systems. Inositol triphosphate (IP3) and Ca2+ often serve as signals of photoexcitation. G proteins also play prominent roles.522... 

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