Biomaterial Database

Pattern formation in the immortal Hydra. 1996

W A Müller

Zoological Institute, University of Heidelberg, Germany. w.muller@sirius.mgen.uni-Heidelberg.de

Well-documented experimental studies with Hydra, done 10-20 years before Mozart was born, marked the dawn of modern developmental biology. Since those days, the immortal and perpetually embryonic hydra has been a classic model system, but despite its deceptively simple appearance, hydra has not yielded its secrets readily. Recent evidence points to a pivotal role of PI-PKC-type signal transduction pathways in morphogenesis: interference with these pathways results in polyps with multiple heads or feet. While molecular techniques are revealing genes involved in pattern realization, a new model of pattern regulation, based on competition for hormonal factors by autoregulatory receptors, emphasizes epigenetic interactions.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D006829	Hydra	A genus of freshwater polyps in the family Hydridae, order Hydroida, class HYDROZOA. They are of special interest because of their complex organization and because their adult organization corresponds roughly to the gastrula of higher animals.	Hydras
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013234	Stem Cells	Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.	Colony-Forming Units,Mother Cells,Progenitor Cells,Colony-Forming Unit,Cell, Mother,Cell, Progenitor,Cell, Stem,Cells, Mother,Cells, Progenitor,Cells, Stem,Colony Forming Unit,Colony Forming Units,Mother Cell,Progenitor Cell,Stem Cell
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D018507	Gene Expression Regulation, Developmental	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.	Developmental Gene Expression Regulation,Embryologic Gene Expression Regulation,Gene Expression Regulation, Embryologic,Regulation of Gene Expression, Developmental,Regulation of Gene Expression, Embryologic,Regulation, Gene Expression, Developmental,Regulation, Gene Expression, Embryologic