Shiho Hayakawa

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The freshwater cnidarian Hydra was first described in 1702 and has been the object of study for 300 years. Experimental studies of Hydra between 1736 and 1744 culminated in the discovery of asexual reproduction of an animal by budding, the first description of regeneration in an animal, and successful transplantation of tissue between animals. Today, Hydra(More)
Cell lineages of cnidarians including Hydra represent the fundamental cell types of metazoans and provides us a unique opportunity to study the evolutionary diversification of cell type in the animal kingdom. Hydra contains epithelial cells as well as a multipotent interstitial cell (I-cell) that gives rise to nematocytes, nerve cells, gland cells, and(More)
Kleptoplastidy is the retention of plastids obtained from ingested algal prey, which may remain temporarily functional and be used for photosynthesis by the predator. We showed that the marine dinoflagellate Dinophysis mitra has great kleptoplastid diversity. We obtained 308 plastid rbcL sequences by gene cloning from 14 D. mitra cells and 102 operational(More)
The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally(More)
Connexin molecules form gap-junction channels in vertebrates and there are at least 20 of them in humans [1]. Intuitively, one would imagine that cardinal features of the cellular machinery, such as gap-junctions, would be highly conserved. Paradoxically, however, Drosophila and Caenorhabditis elegans do not have connexin genes, but instead use innexins for(More)
Multicellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals. A notable exception exists in single-celled eukaryotes called dinoflagellates, some of which have an eye-like 'ocelloid' consisting of subcellular analogues to a cornea, lens, iris, and retina. These(More)
Connexin molecules form gap-junction channels in vertebrates and there are at least 20 of them in humans [1]. Intuitively, one would imagine that cardinal features of the cellular machinery, such as gap-junctions, would be highly conserved. Paradoxically, however, Drosophila and Caenorhabditis elegans do not have connexin genes, but instead use innexins for(More)
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