Hypodermis Research Articles

Changes in epibiotic burden during the intermolt of Daphnia determined by hypodermal retraction stages

Changes in epibiotic burden during the intermolt of Daphnia determined by hypodermal retraction stages

Neuroendocrine control of nitrogen metabolism in the indian field crab Oziotelphusa s. senex fabricius—II. Enzyme activities

1. 1. The increase in elimination of NPN and of concentration of NPN in tissues, primarily in the form of NH 3, reported earlier ( Comp. Biochem. Physiol. 67B, 437, 1980) as a consequence of extirpation of eyestalks from fresh-water crab, is here traced to inhibition, by neurohumors from the eyestalks, of enzymes producing NH 3 by hydrolysis of amides and oxidation of amino acids. 2. 2. Glutaminase activity was inhibited by an eyestalk factor, in haemolymph (HL), hepatopancreas (HP), muscle (M), hypodermis (HD), and gill (G). Asparaginase activity was inhibited only in HP, HD, and G. Activity of glutamase dehydrogenase was inhibited in M, HD and G. 3. 3. The activities of ala and asp aminotransferases were stimulated in HP, M M, HD and G. 4. 4. No general pattern of action on oxidoreductases in general was demonstrated, or on activity of arginase, xanthine dehydrogenase, protease, or ribonuclease, although effects on some of these were evident in some tissues. 5. 5. We conclude that the neuroendocrine system of the eyestalk of this crab acts during intermoult to conserve nitrogen stores and to promote turnover of amino acids, through direct action on the enzymes involved.

Some ultrastructural changes in cuticle and hypodermis of Aporcelaimellus during the first moult (Nematoda: Dorylaimoidea)

The architecture of the body cuticle of juvenile Aporcelaimellus is identical to that of the adult, but the infracuticle is absent in the first stage juvenile. The cuticle is composed of fiber layers that are separated and perforated by a lacunar system. The lacunae are thought to contribute to the flexibility of the cuticle. The hypodermis is cellular. The cell-to-cell contacts consist of convoluted membranes that are often fortified by zonulae adhaerentes. The first moult was studied in specimens in the A1- and A5-stage (terminology of Coomans and van der Heiden, 1971). A stage chronologically prior to the A1-stage was found, which is referred to as A0-stage in this paper. During the A0-stage, the hypodermal cells become hypertrophic and gland-like. The zonulae adhaerentes seem to be replaced by septate desmosomes. The cuticle separates from the hypodermis. Cuticle-formation is in progress during the A1-stage. The outer layers of the new cuticle are laid down by the hypodermal cells underneath the old cuticle. Projections from the epithelium become enclosed within the new cuticle. Cuticle-secretion is completed during the A5-stage, but hardiy any differentiation is discernable. At the end of the A5-stage differentiation initiates by condensation of the filamentous material. The hypodermal projections gradually retract from the cuticle. It is concluded that the lacunar system originates from the differentiation-process. No evidence was found for partial resorption of the old cuticle.

Incorporation of <sup>14</sup>C-phenylalanine or <sup>14</sup>C-tyrosine into the Hypodermal Cuticle of the Silkworm. I

Incorporation of <sup>14</sup>C-phenylalanine or <sup>14</sup>C-tyrosine into the Hypodermal Cuticle of the Silkworm. I

Structure and Development of Hypodermis in Dacrydium taxoides Leaves

American Journal of BotanyVolume 40, Issue 5 p. 366-371 Article STRUCTURE AND DEVELOPMENT OF HYPODERMIS IN DACRYDIUM TAXOIDES LEAVES C. L. Lee, C. L. Lee Department of Botany, University of Illinois, Urbana, IllinoisSearch for more papers by this author C. L. Lee, C. L. Lee Department of Botany, University of Illinois, Urbana, IllinoisSearch for more papers by this author First published: 01 May 1953 https://doi.org/10.1002/j.1537-2197.1953.tb06492.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume40, Issue5May 1953Pages 366-371 RelatedInformation