Cnidarians are the most primitive animals to possess a nervous system. This phylum is composed of the classes Scyphozoa (jellyfish), Cubozoa (box jellyfish), and Hydrozoa (e.g., Hydra, Hydractinia), which make up the subphylum Medusozoa, as well as the class Anthozoa (sea anemones and corals). Neuropeptides have an early evolutionary origin and are already abundant in cnidarians. For example, f...

We previously reported that isolation of symbiotic Chlorella-like algae from the Florida strain of Hydra viridis induced replication of a virus (designated HVCV-1) in the algae. We now report that isolation of symbiotic Chlorella-like algae from four other sources of green hydra and one source of the protozoan Paramecium bursaria also induced virus synthesis. Algae from one of these hydra conta...

Apoptosis is a normal process by which cells die and are eliminated from tissue by phagocytosis [1]. It is involved in regulating cell numbers in adult tissues and in eliminating 'excess' cells during embryogenesis and development. Apoptosis is mediated by activation of caspases, which then cleave a variety of cellular substrates and thereby cause the characteristic morphology of apoptotic cell...

The cell cycle parameters of epithelial cells of Hydra attenuata are described. Specifically the rate of proliferation and the fraction of proliferating cells have been determined under conditions of defined growth rate. Techniques involved standard methods of cell cycle analysis using histological and tissue maceration preparations; pulse-chase and continuous labelling with [H]thymidine follow...

Background: The freshwater cnidarian Hydra temporarily binds itself to numerous natural substrates encountered underwater, such as stones, leafs, etc. This adhesion is mediated by secreted material from specialized ectodermal modified cells at the aboral end of the animal. The means by which Hydra polyps attach to surface remain unresolved, despite the fact that Hydra is a classic model in deve...

Three types of interstitial stem cell subpopulation were isolated from Hydra magnipapillata, and their roles in sex determination were examined. A subpopulation of interstitial stem cells restricted to the sperm differentiation pathway was isolated previously from strain nem-1 (male). Another subpopulation restricted to the egg differentiation pathway was also isolated from the same strain. Hyd...

This article describes the C.mmp/Hydra project at CarnegieMellon University. Included are detailed descriptions of the PMS structure of C.mmp (a multiprocessor built from minicomputers) and its major components. An overview of its operating system. Hydra, is provided with emphasis on those sections most concerned with and influenced by the architecture. The project is also discussed in terms of

SYNOPSIS. Hox genes in bilaterians specify distinct regions along the anteriorposterior axis. A question of interest is when in metazoan evolution did this class of genes take on this function. Hox genes have been isolated from a number of cnidarian species including hydra. The expression patterns of two of them, Cnox3 and Cnox-2 have been examined in adult hydra. Cnox-3, a labial homologue, pl...