Cnidaria
A phylum of radially symmetrical invertebrates characterized by possession of stinging cells called nematocysts. It includes the classes ANTHOZOA; CUBOZOA; HYDROZOA, and SCYPHOZOA. Members carry CNIDARIAN VENOMS.
Hydrozoa
Sea Anemones
Hydra
Scyphozoa
Cubozoa
Anemone
A plant genus of the family RANUNCULACEAE that contains triterpene saponins. The root of Anemone raddeana is the source of a Chinese folk medicine, zhu jie xian fu. The common name of liverwort is also used with other plants. This genus is unrelated to SEA ANEMONES.
Anthozoa
A class in the phylum CNIDARIA, comprised mostly of corals and anemones. All members occur only as polyps; the medusa stage is completely absent.
Nematocyst
A double-walled capsule found in jellyfish and other CNIDARIA whose functions include prey capture, defense, locomotion, and attachment. Nematocysts contain toxic CNIDARIAN VENOMS which are injected into the victim via a barbed tubule.
Ctenophora
Phylum of marine colenterates characterized by eight comb rows of fused cilia on the body surface. In contrast to CNIDARIA they lack stinging cells, but they are voracious predators and possess sticky cells (colloblasts) for capturing prey. Most species are transparent and many exhibit bioluminescence.
Placozoa
Evolution, Molecular
Cnidarian Venoms
Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.
Porifera
The phylum of sponges which are sessile, suspension-feeding, multicellular animals that utilize flagellated cells called choanocytes to circulate water. Most are hermaphroditic. They are probably an early evolutionary side branch that gave rise to no other group of animals. Except for about 150 freshwater species, sponges are marine animals. They are a source of ALKALOIDS; STEROLS; and other complex molecules useful in medicine and biological research.
RNA, Ribosomal, 28S
RNA, Ribosomal, 18S
DNA, Ribosomal
Body Patterning
The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Metamorphosis, Biological
Genes, Homeobox
Genes that encode highly conserved TRANSCRIPTION FACTORS that control positional identity of cells (BODY PATTERNING) and MORPHOGENESIS throughout development. Their sequences contain a 180 nucleotide sequence designated the homeobox, so called because mutations of these genes often results in homeotic transformations, in which one body structure replaces another. The proteins encoded by homeobox genes are called HOMEODOMAIN PROTEINS.
DNA, Mitochondrial
Encyclopedias as Topic
Polyps
Discrete abnormal tissue masses that protrude into the lumen of the DIGESTIVE TRACT or the RESPIRATORY TRACT. Polyps can be spheroidal, hemispheroidal, or irregular mound-shaped structures attached to the MUCOUS MEMBRANE of the lumen wall either by a stalk, pedunculus, or by a broad base.