. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DOM TRANSPORT AND METABOLISM IN SPONGE LARVAE 163 cannot be ascertained by light-microscopic autoradiog- raphy of glutaraldehyde-fixed material. Glutaraldehyde is a good preservative of cellular details, in part because it acts by cross-linking primary amines. This activity may result in a false intracellular localization of the label, if the label-bearing molecule resides in the extracellular space ( Peters and Ashley. 1967). However, the au- toradiographic analysis presented here was designed to ascertain whether the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DOM TRANSPORT AND METABOLISM IN SPONGE LARVAE 163 cannot be ascertained by light-microscopic autoradiog- raphy of glutaraldehyde-fixed material. Glutaraldehyde is a good preservative of cellular details, in part because it acts by cross-linking primary amines. This activity may result in a false intracellular localization of the label, if the label-bearing molecule resides in the extracellular space ( Peters and Ashley. 1967). However, the au- toradiographic analysis presented here was designed to ascertain whether the label, after transport, was distributed throughout the entire larval body, not to determine the pathway of material movement (paracellular or transcel- lular). After 10 min of exposure to either 3H-alanine or pal- mitic acid, the label is found in or around the cells of the epidermis (Fig. 4A), as evidenced in the autoradiograms by the appearance of silver granules overlying these cells. Even though larvae were continuously exposed to the label for up to 2 h. examination of the autoradiograms (Fig. 4A-C) indicates that most of the label remained associated with the cells of the epidermis. Discussion Most research on the larvae of demosponges has focused on their morphological or behavioral characters ( Berquist et «/.. 1970; Woollacott, 1990, 1993; Kaye and Reiswig, 1991). The morphology of the epidermis of larvae of Teiiania ignis (subclass Poecilosclerida) closely ap- proximates that described for larvae of the haplosclerid demosponge Haliclonn tnhijera (Woollacott, 1993). For both species, the epidermis is composed chiefly of elongate columnar cells (each with a single cilium arising from an epidermal crypt). The posterior pole is aciliate in both, but the enlarged ciliary band that exists at the intersection of the lateral and posterior surfaces in H. ttibifera larvae is wanting in larvae of T. ignis. The physiological signif- icance of the epidermal crypts remains un
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
