(n. pl.) Those animals in which the protoplasmic mass, constituting the egg, is converted into a multitude of cells, which are metamorphosed into the tissues of the body. A central cavity is commonly developed, and the cells around it are at first arranged in two layers, -- the ectoderm and endoderm. The group comprises nearly all animals except the Protozoa.
Example Sentences:
(1) Phyla as diverse as insects, birds, and mammals possess distinct HRAS and KRAS sequences, suggesting that these genes are essential to metazoa.
(2) The unique structure of these cilia has systematic and phylogenetic significance for the Acoela, and it is argued that ultrastructural characters in general, including characters of organelles, can be validly applied to the phylogeny and systematics of the Metazoa.
(3) In Metazoa single receptory flagellar cells are differentiated; they realize conservatively some receptive molecules that are already prepared by their ancessors--Eukaryota.
(4) Together with previous results that showed the existence of a nonfibrillar collagen in the same species, these data demonstrate that at least two collagen gene families are represented in the most primitive metazoa.
(5) The origin of metazoa implies the passage from an eukarote protozoan to a protozygote ancestor of a metazoan zygote.
(6) RNA synthesis and processing in A. nidulans mitochondria therefore resembles the events occurring in metazoa rather than yeast.
(7) Comparison of the sequences obtained from the different species indicate that the metazoan lineages all appear to have arisen at approximately the same time and significantly later than the time of divergence of yeast from the common ancestor of the Metazoa.
(8) This is the first report in a nutritional role of peptides in invertebrate metazoa.
(9) In these phylogenies the Ciliophora diverged from the eukaryotic line of descent as a loose phylogenetic grouping during a radiative period that gave rise to the Fungi, the Plantae and the Metazoa.
(10) Analysis of messenger RNA splicing in yeast and in metazoa has led to the identification of an RNA molecule in a lariat conformation.
(11) These findings support the view that Myxosporidia are Metazoa and raise the problem of their origin.
(12) A variety of microorganisms and metazoa was observed, including a baculovirus, gram-negative bacteria, rickettsia-like organisms, amoebae, trypanosomatid flagellates, cephaline gregarines, and microsporidia.
(13) Organisms with defective or with no lymphocytic function are able to live for a certain time while metazoa cannot develop and exist without cells capable of phagocytosis.
(14) Polyploidy--the doubling of chromosome sets of cells caused by a stop of mitosis at different levels of the mitotic cycle--is a phenomenon widely observed in plants, protozoa, metazoa, and animals.
(15) In Metazoa two types of locomotion take place according to the function of regulatory genes: initial flagellar and muscular definitive apparatus.
(16) The presence of spasmins in other Protozoa and in some Metazoa was also investigated.
(17) At this stage, the swimming Metazoa of the thermocline could adapt to a benthic environment on the shelves by developing exoskeletons.
(18) These analyses indicate that (i) the Metazoa is a monophyletic taxon; (ii) the Deuterostomia is a monophyletic taxon; (iii) the Annelida-Mollusca lineage is the sister group of an arthropod subgroup; and (iv) the last common ancestor of the Annelida-Mollusca lineage is most parsimoniously derived from a segmented, hemocoelic ancestor with an open circulatory system.
(19) Tubulin and dinein with ATPh-ase activity are included in the flagella composition of LSS in Eukaryota, actin and miozin--with a high ATPh-ase activity--in composition of LSS myofilaments in ameboid Eukaryota and locomotor musculature in Metazoa.
(20) Comparative evidence on the lack of three important organelles (flagella, Golgi-complex, mitochondria) in cells and organisms at the cellular level of organization has been summarized for all the four eukaryotic kingdoms--Protista, Fungi, Plantae and Animalia (Metazoa).
Multicellular
Definition:
(a.) Consisting of, or having, many cells or more than one cell.
Example Sentences:
(1) Calcium channels, which play a primary role in the control of the calcium influx into cardiac cells, were initially studied by recording macroscopic currents in multicellular preparations.
(2) We have used this dye to enable us to track individual cells, as they move through multicellular tissues in later Dd stages.
(3) Statistical analysis of 251 phylogenetically informative nucleotide positions rejects the "volvocine lineage" hypothesis, which postulates a monophyletic evolutionary progression from unicellular organisms (such as Chlamydomonas), through colonial organisms (e.g., Gonium, Pandorina, Eudorina, and Pleodorina) demonstrating increasing size, cell number, and tendency toward cellular differentiation, to multicellular organisms having fully differentiated somatic and reproductive cells (in the genus Volvox).
(4) Our results show the feasibility of back-extrapolating multicellular tumour spheroid growth curves to obtain survival estimates that can be applied to establish sublethal damage repair capacity.
(5) In multicellular preparations, phenylephrine caused a concentration-dependent positive inotropic effect, an increase in action potential duration, and a decrease in resting potential; the effects were antagonized by phentolamine.
(6) Cyclic-AMP-induced prespore protein synthesis and the proportion of prespore cells in multicellular aggregates are also not affected by bypassing or inhibiting the cAMP-induced pHi increase.
(7) They are thought to be a major source of DNA damage leading to aging and cancer in multicellular organisms.
(8) Analysis of ribosomal RNAs agrees with traditional analyses of morphological and developmental characters that all multicellular animals probably arose from a common ancestor, but highlights one of the major limitations of the various mathematical algorithms used.
(9) Multicellular aggregates were dissociated either immediately before or immediately after irradiation and assayed under conventional conditions.
(10) Rapid cooling contractures (RCCs) were used to assess changes in sarcoplasmic reticulum (SR) Ca content in both isolated rabbit ventricular myocytes and multicellular preparations.
(11) The involvement of microorganisms or "hyperparasites" during the host associations of multicellular parasites was described.
(12) The radiation response of multicellular spheroids, initiated from a human melanoma xenograft (E.E.)
(13) Antiproliferative effects of free retinoic acid (RA) and liposome-encapsulated RA (RAlp) were compared in a squamous carcinoma system using both monolayer cells and multicellular tumor spheroids (MTS), an in-vivo-like model with three-dimensional histological structure.
(14) The histone H3 and H4 genes are shown to be expressed in both Arabidopsis plantlets and transitory multicellular suspension.
(15) In cells transformed with this vector, the gene fusion showed the same temporal regulation as the endogenous gene during multicellular development and, like endogenous prestalk genes, was highly inducible by cyclic AMP in in vitro cell cultures.
(16) The mechanisms a macrophages uses to block the replication of a virus may be totally ineffective in the destruction of a multicellular helminth, such as Schistosoma mansoni.
(17) A significant negative correlation existed between parathyroid aluminium and osteoblastic surfaces (P less than 0.05), but no correlation was found with bone formation rate at tissue and bone multicellular units levels.
(18) We have compared the response to a number of cytotoxic drugs of cells treated either within intact multicellular spheroids or as isolated cells following spheroid disaggregation.
(19) This is discussed in terms of the physiological adaptation and development of multicellular-tissue systems.
(20) Analysis of protein sequences shows that many proteins in multicellular organisms have evolved by a process of exon shuffling, deletion and duplication.