(n.) Any plant of the natural order Cycadaceae, as the sago palm, etc.
Example Sentences:
(1) Evidence is presented in support of the proposal that heavy use of certain toxic plants, notably cycads, a traditional source of food and medicine for the Chamorro people, plays an important etiological role.
(2) Since long periods may elapse between cycad exposure and the appearance of neurological disease in humans, cycads may harbor a "slow toxin" that causes the postmitotic neuron to undergo slow irreversible degeneration.
(3) We conducted an investigation of the levels of the neurotoxin 2-amino-3-(methylamino)-propanoic acid (BMAA) in cycad flour.
(4) Cycad nuts, widely used as human food in tropical and subtropical areas, contain a potent carcinogen, methyl azoxymethanol, which is more or less removed prior to use by leaching in water.
(5) Limited diversity was found among cyanobionts from a cultivated population of cycads at a field site in Florida.
(6) The DNA sequence of the small-subunit ribosomal RNA coding region for the cycad Zamia pumila L. was determined.
(7) It roamed a tropical island habitat 210 million years ago, racing around in herds and pausing from time to time to stand on hind legs to nibble with razor-sharp teeth on the leaves of palm-like cycad trees.
(8) Although cause-effect relationships cannot be established by epidemiologic studies alone, we have shown in all three affected population groups that individuals develop the amyotrophic lateral sclerosis variant of this disorder after heavy exposure to the raw or incompletely detoxified seed of neurotoxic cycad plants.
(9) 2-Amino-3-(methylamino)-propanoic acid (BMAA) is a neurotoxic, excitatory amino acid which has been linked through cycad use and consumption with the onset of a variant of amyotrophic lateral sclerosis occurring with high incidence in the western Pacific region.
(10) Sperm formation was studied in the fern, Marsilea, and the cycad, Zamia, with particular emphasis on the centrioles.
(11) However, such doses are orders of magnitude greater than those available from dietary or medicinal use of cycads.
(12) Methylazoxymethanol, a carcinogenic and hepatotoxic methylating agent prepared from cycad plants, has been found to be a good mutagen in Salmonella typhimurium.
(13) This paper explores the possible relationship between tumorigenesis and long-latency neurotoxicity, and discusses possible biologic markers of cycad exposure and subclinical neurodegenerative disease.
(14) The main points presented were (1) a definition of what is truly ALS, in the clinical and pathological sense, based on what is called "classical" ALS: (2) how neurons may be cultured to provide a valuable experimental tool; (3) the significance of lipid abnormalities in ALS and the characterization of the ALS-like syndromes produced by hexosaminidase A deficiency; (4) the possible role of autoimmune disease as it may accompany classical ALS and nerve growth factor derived from skeletal muscle; (5) the western Pacific form of ALS as it has been intensely studied and has given rise to two hypotheses on pathogenesis: mineral toxicity caused by secondary hyperparathyroidism and poisoning through ingestion of the cycad seed, and (6) the possible abiotropic interaction of one or many environmental toxins over a lifetime with the aging nervous system, depleting it of its frail reserve of neurons.
(15) There was no significant difference in the toxicity of extracts prepared from the female gametophyte tissue of C. circinalis, C. revoluta, and C. media, common wheat flour, and 13 of 17 cycad flour samples.
(16) DNA was prepared from cyanobacteria freshly isolated from coralloid roots of natural populations of five cycad species: Ceratozamia mexicana mexicana (Mexico), C. mexicana robusta (Mexico), Dioon spinulosum (Mexico), Zamia furfuraceae (Mexico) and Z. skinneri (Costa Rica).
(17) We believe that the cycad seeds which usually cause no immediate adverse symptoms when prepared and eaten as flour, or applied topically as medicine, can give rise to widespread and severe nerve cell degeneration after a latency of many decades.
(18) After weaning, groups of rats were fed a semi-purified diet containing fiddlehead greens (the unfuried frond of the ostrich fern Matteuccia struthiopteris), mature bracken fern (Pteridium aquilinum), or cycad meal (Cycas circinalis), or this diet plus aflatoxin B1.
(19) Methylazoxymethanol (MAM) is the short-lived toxic and carcinogenic aglycone of cycasin, a natural component of the cycad plant.
(20) Moreover, the complexity of restriction patterns shows that a mixture of Nostoc strains can associate with a single cycad species although a single cyanobacterial strain can predominate in the root of a single cycad plant.
Zamia
Definition:
(n.) A genus of cycadaceous plants, having the appearance of low palms, but with exogenous wood. See Coontie, and Illust. of Strobile.
Example Sentences:
(1) In Zamia, similar stages are found during sperm formation, although here the number of flagella on each sperm is close to 20,000 and the blepharoplast measures about 10 micro in diameter.
(2) Sheep mortalities caused by the ingestion of leaves of the zamia palm (Macrozamia reidlei) were recorded from 6 properties in Western Australia from 1966 to 1971.
(3) The DNA sequence of the small-subunit ribosomal RNA coding region for the cycad Zamia pumila L. was determined.
(4) The Zamia small-subunit rRNA was found to be 1813 nucleotides in length and approximately 92% identical to published angiosperm small-subunit rRNA sequences.
(5) Sperm formation was studied in the fern, Marsilea, and the cycad, Zamia, with particular emphasis on the centrioles.
(6) DNA was prepared from cyanobacteria freshly isolated from coralloid roots of natural populations of five cycad species: Ceratozamia mexicana mexicana (Mexico), C. mexicana robusta (Mexico), Dioon spinulosum (Mexico), Zamia furfuraceae (Mexico) and Z. skinneri (Costa Rica).
(7) The sequence of Zamia represents the earliest divergence from the higher plant lineage reported to date for small-subunit rRNA data.
(8) These cyanobacteria were root endophytes of several plants of Zamia integrifolia and one of Dioon.