Zamia staggers
Encyclopedia
Zamia staggers is a form of cycad toxicosis, a term for the fatal nervous disease affecting cattle where they browse on the leaves or fruit of cycad
s. It is characterised by irreversible paralysis of the hind legs because of the degeneration of the spinal cord
. It is caused by a toxin
, often called cycasin or macrozamin, a β-glycoside (the sugar of which is primeverose) of methylazoxymethanol (MAM), and which is found in all cycad genera. Following ingestion the sugar is removed by bacterial glycosidase in the gut, with the MAM being absorbed. The metabolized toxin produces tumours of the liver, kidney, intestine and brain after a latent period which may be a year or longer. The disease has been known in Australia since the 1860s and was the subject of a Queensland Government
investigation during the 1890s.
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s. It is characterised by irreversible paralysis of the hind legs because of the degeneration of the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. It is caused by a toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
, often called cycasin or macrozamin, a β-glycoside (the sugar of which is primeverose) of methylazoxymethanol (MAM), and which is found in all cycad genera. Following ingestion the sugar is removed by bacterial glycosidase in the gut, with the MAM being absorbed. The metabolized toxin produces tumours of the liver, kidney, intestine and brain after a latent period which may be a year or longer. The disease has been known in Australia since the 1860s and was the subject of a Queensland Government
Government of Queensland
The Government of Queensland is commonly known as the "Queensland Government".The form of the Government of Queensland is prescribed in its Constitution, which dates from 1859, although it has been amended many times since then...
investigation during the 1890s.
See also
- beta-Methylamino-L-alanine
- Methyl-ONN-azoxymethanol beta-D-glucosyltransferaseMethyl-ONN-azoxymethanol beta-D-glucosyltransferaseIn enzymology, a methyl-ONN-azoxymethanol beta-D-glucosyltransferase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are UDP-glucose and methyl-ONN-azoxymethanol, whereas its two products are UDP and cycasin....