Comparative ultrastructural study on tris 1‐aziridinyl phosphine oxide prefixed cuticles of some oligochaetes

Abstract

The cuticle of five species of Oligochaeta, chosen to represent differences in size and a variety of biotopes, was studied electron microscopically after fixation with the acrolein-TAPO-osmium tetroxide method. Five distinct layers in the cuticle of all studied species were found. Staining with lead and uranyl ions or with silver proteinate visualized basically the same structural components of the cuticle, but the degree of electron opacity and the distribution of the electron-opaque stain in these components differed according to the staining method used. Since the acrolein-TAPO-osmium tetroxide method visualized the cuticular zones preferentially stained by Thiery's silver proteinate method, it was concluded that the TAPO method may be considered suitable for the visualization of polysaccharides. Staining with phosphotungstic acid provided some information on the composition of the cuticle of Oligochaeta not obtained by staining ultrathin sections with lead and uranyl ions nor with silver proteinate. The conclusion is that phosphotungstic acid binds to polysaccharides which do not contain vicglycol groups nor active sites responsible for the positive reaction with lead and uranyl salts. Structural components in the cuticle of the oligochaetes studied were characteristic for each species. The taxonomic value of such components, however, must be confirmed by examination of a larger number of species of oligoc h ae tes. 143157

Cuticular ultrastructure in some marine oligochaetes (Tubificidae)

“…In Eisenia.foetida, the electron-lucent layer is followed by 2 more layers with increasing density towards the outer surface. Layers in the epicuticle were also described by Djaczenko &Calenda Cimmino (1974) andRodriguez Alves et al( 1984) for some Brazilian earthworms. The inner electron-lucent and the outer denser layers of the epicuticle also correspond to the epicuticular structure found in polychaetes (Storch 1988).…”

“…No spermatozoa of the species studied in this paper have been ultrastructurally described, and the cuticular morphology of the species selected by ErsCus & Ferraguti is unknown. The information about cuticular fiber arrangement in this and additional papers (Djaczenko & Calenda Cimmino 1974;Giere 1981Giere , 1983Giere , 1985Jamieson 1981Jamieson , 1992Richards et al 1982;Giere & Langheld 1987;Giere et al 1988) can, however, be discussed in relation to the general suggestions of the tree presented by ErsCus & Ferraguti.…”

“…Collagen fibers. The first ultrastructural studies of the cuticle in Oligochaeta (Lumbricidae and Enchytraeidae) noted a rather uniform pattern of the collagen fibers usually referred to as an "orthogonal grid" (Reed & Rudall 1948;Randall 1957;Millard & Rudall 1960;Ruska & Ruska 1961;Coggeshall 1966;Goodman & Parrish 1971;Burke 1974a;Djaczenko & Calenda Cimmino 1974;Richards 1974Richards , 1977Burke & Ross 1975;Humphreys & Porter 1976;Rodriguez Alves et al 1984). However, a different kind of fiber arrangement was reported by Krall (1968) for the naidid Dero obtusa, the cuticle of which was described as having less organized fibers running parallel to the longitudinal axis of the body.…”

“…Epicuticle and matrix. Djaczenko & Calenda Cimmino (1974) studied the composition of the cuticular matrix in 5 oligochaete species (Tubifex tubiyex, Enchytraeus albidus, Eisenia foetida, Lumbricus terrestris, and Octolasium complanatum). In all 5, they could distinguish several components of the matrix: small, uniformly electron-dense granules 6-1 1 nm wide; filaments about 4 nm wide and of variable lengths; round or oval bodies with alternating electrondense and electron-lucent zones with a maximum diameter of 150 nm; uniformly electron-dense bodies 100 nm wide; and electron-lucent bodies with a trilaminar membrane.…”

“…Instead, the author concluded that different arrangements of the collagen fibers were related to the locomotory patterns of the worm. Djaczenko & Calenda Cimmino (1974) studied 5 oligochaete species (Tubifex tubijex, Eisenia foetida, Lumhricus terrestris, Enchytrueu,\ ulbidus, and Octolasium complanatum) from different habitats and found little variability in the ultrastructure of the cuticle, which led them to conclude that these structurer have taxonomic value. Examples of animal groups where ultrastructure of the cuticle and epidermis have been used to find relationships among animals are Gastrotricha (Rieger & Rieger 1976, 1977, I'olychaeta (Westheide & Rieger 1978), and Platyhelminthes (Ehlers 1992).…”