(n.) Any species of turbellarian worms belonging to Planaria, and many allied genera. The body is usually flat, thin, and smooth. Some species, in warm countries, are terrestrial.
Example Sentences:
(1) Total lipid content of planariae is equal to 28.70% of lyophylized weight, 21.70% of them being presented by phospholipids.
(2) Attra-tion of the worms to stool material was examined by placing planaria inside square whose boundries were constructed of fecal smears.
(3) In comparison, mechanical sectioning proved to be more appropriate for increasing the number of planaria.
(4) These results are in agreement with those of other authors who attribute an essential role to undifferentiated cells during regeneration of the adult planaria.
(5) One hundred planaria averaging 8 mm in length could be sectioned into 600 segments in approximately 18 min; regeneration was achieved by approximately 94% of these segments, usually within 8 days after sectioning.
(6) The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase in SnCl2 concentration from 0.13 to 1.3 microM, reaching a plateau in the range of 1.3-130 microM then decreasing with 1300 microM.
(7) The ocellar potential (OP) of planaria was recorded using microelectrode techniques.
(8) As serotonin is normally present in planaria, it is postulated that a serotonin-dependent regulation of adenylate cyclase activity plays a physiological role in this species.
(9) These results suggest that light receptors in these planaria might have evolved away from the body surface and are located in the ocelli.
(10) p-Chlorophenylalanine (pCPA) caused an increase in looping and locomotion speed in planaria (Dugesia dorotocephala).
(11) Planaria Dugesia dorotocephala were bilaterally enucleated, decapitated caudal to the auricles, or sectioned at the level of the pharynx.
(12) Planaria that regenerated from head sections showed more looping 6 and 11 days later than tail regenerates, regenerates from untreated worms, and uncut worms.
(13) The particulate fraction prepared after homogenization of planaria Polycelis tenuis in a buffer containing 3 mM EDTA and 15 mM 2-mercaptoethanol possesses an adenylate cyclase activity which was enhanced two-fold by serotonin and 20-fold by the nucleotide analog guanosine 5'-(beta-gamma-imino)triphosphate, Gpp(NH)p; when present together, the two activators exhibited a marked synergistic effect.
(14) Epinephrine, ephedrine, dopamine and isoproterenol considerably influence carbohydrate utilization in planaria.
(15) Study of planaria cells, which are the result of dissociated fragments cultivated in vitro, allows the evolution of two cell groups to be followed: (1) Differentiated cells, which do not divide, and do not dedifferentiate either, incorporate leucine and uridine at a rate which remains stable for the whole duration of the culture.
(16) In some molluscs (Aplysia and Fusitriton) and insects (silkworm and cricket), occurrence and distribution of neuropeptides in the nervous system and gut were studied with following results: in these invertebrates and also in planaria, PP-like immunoreactivity is extensively distributed in neurons and (in insects) in gut endocrine paraneurons.
(17) During traumatic regeneration of Planaria Polycelis tenuis, determination of serotonin, noradrenaline and dopamine levels revealed important variations of serotonin and catecholamines from the time of excision.
(18) Since 1961 it has been known that human infections are usually acquired by purposeful or accidental ingestion of infective larvae in terrestrial mollusks, planaria and fresh-water crustacea.
(19) Using PCR, some Antennapedia-type homeoboxes were cloned from the genome of two other Platyhelminthes, Dugesia tigrina (planaria) and Fasciola hepatica.
(20) Other organisms including Herpobdella testacea and Helobdella stagnalis (Hirudinea), Acellus aquaticus (Isopoda), Planaria lugubris (Turbellaria) and L. truncatula egg clusters failed to interfere with miracidial host-finding.
Planarian
Definition:
(n.) One of the Planarida, or Dendrocoela; any turbellarian worm.
Example Sentences:
(1) In planarians bisected transversely through the pharyngeal region, the decolouration occurs only in the cephalic segment, and the caudal segment remains dark.
(2) Comparison of the experimental results with previous observations on respiration of planarians under similar conditions shows that changes in the level of respiration during starvation and feeding correlate with the content of mitochondrial protein.
(3) We have detected sequence heterogeneity in the cytochrome c oxidase subunit I (COI) gene of freshwater planarian, Dugesia japonica, collected in one locality.
(4) Appropriate preparation of food, control of mollusks and planarians, and elimination of rodents are important measures in limiting the further spread of eosinophilic meningitis caused by A. cantonensis.
(5) The spatial proximity and connectivity of the synapses suggest modes of action permitting greater functional complexity to the planarian brain than previously supposed.
(6) These results are at variance with the generally accepted hypothesis that, in planarians, epidermal cells originate from the parenchyma and the epidermis is not an autonomous tissue.
(7) Many morphological, electrophysiological, and pharmacological features of planarian neurons, as well as synaptic organization, are reminiscent of the vertebrate brain.
(8) It is suggested that planarians lack a direct mechanism for DDT detoxification, since two North American and one European species are known to metabolize DDT initially to DDE and DDD.
(9) Planarians developing from isolated regenerates, when pretreated with epinephrine at different periods of their second regeneration, show a higher rate of sugar uptake than the controls, which were not treated with epinephrine.
(10) In the presence of other planarians, the brain exerts an influence (probably neurohormonal) to suppress fissioning.
(11) Research in the field of planarian regeneration on the one hand, and a general survey of embryology on the other, throw doubt upon the reality of supra-cellular controls, which are still at the basis of all modern concepts of morphogenesis.
(12) Treatment of intact planarians with sublethal concentrations of cadmium sulfate and 12-O-tetradecanoylphorbol-13-acetate (TPA) induced a type of infiltrating tumor that proved to be potentially lethal.
(13) The data obtained are to be taken into account in neurobiological studies on planarians.
(14) Treatment with sublethal concentrations of cadmium sulfate produced a benign, but persistent, tumor in a small percentage of the planarians.
(15) Various surgical cuts were made to ablate selected portions of the central nervous system of isolated and grouped planarians in order to ascertain the inhibitory or facilitatory effects of these in the physiological mediation of such control on the SPF system.
(16) The possibility of gastrointestinal pseudoparasitism by the free-living land planarian, Bipalium kewense, was tested by feeding and survival experiments.
(17) In the central nervous system of some species of several invertebrate phyla, including land planarians (Platyhelminthes), ribbon worms (Nemertina), slugs (Mollusca), polychaetes, earthworms and leeches (Annelida), pill bugs (Arthropoda), and beard worms (Pogonophora), salmon calcitonin-immunoreactive cells and rat calcitonin gene-related peptide (CGRP)-immunoreactive cells were found by immunohistochemistry.
(18) The presence of adenylate-cyclase on the membrane suggests that it might mediate different stimulus-secretion coupling by increasing cyclic AMP synthesis in specialized areas of the planarian.
(19) On the basis of these observations, we hypothesize that SP may be one of the postulated growth factors necessary for the stimulation of proliferation, and to a lesser extent differentiation of cells in intact and regenerating planarians.
(20) The extracts of regenerating planarians contain factors which activate and inhibit cell proliferation in culture.