Abrus precatorius

Taxobox
name = Jequirity

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image_width = 250px
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Fabales
familia = Fabaceae
subfamilia = Faboideae
tribus = Abreae
genus = "Abrus"
species = "A. precatorius"
binomial = "Abrus precatorius"
binomial_authority = L.

"Abrus precatorius", known commonly as Jequirity, Crab's Eye, Rosary Pea, John Crow Bead, Precatory bean, Indian Licorice or Saga Tree ("Abrus precatorius"), is a legume with long, pinnate-leafleted leaves. It is also known as "Gunja" in Sanskrit and some Indian languages. Their seeds are often used as beads and in percussion instruments. The seed contains a toxic poison Abrin that is only harmful when swallowed if the seeds are broken, as they have a hard seed coat. The plant is native to Indonesia and grows in tropical and subtropical areas of the world where it has been introduced. It has a tendency to become weedy and invasive where it has been introduced.

Toxin

The toxin present in "Abrus precatorius" is a close relative to ricin called abrin. It is a dimer consisting of two protein subunits, termed A and B. The B chain facilitates abrin's entry into a cell by bonding to certain transport proteins on cell membranes, which then transport the toxin into the cell. Once inside the cell, the A chain prevents protein synthesis by inactivating the 26S subunit of the ribosome. One molecule of abrin will inactivate up to 1,500 ribosomes per second. Symptoms are identical to those of ricin, except that the fatal dose of ricin is approximately 75 times greater than the fatal dose of abrin. Abrin can kill with a circulating amount of less than 3 μg (micrograms).

Uses

The seeds of "Abrus precatorius" are much valued in native jewelry for their bright coloration. The third of the bean with the hilum (attachment scar) is black, and the rest is bright red, suggesting a ladybug. Jewelry-making with jequirity seeds is dangerous, and there have been cases of death by a finger-prick while boring the seeds for beadwork. However, it has long been a symbol of love in China.

References

*List of plants of Caatinga vegetation of Brazil
* [http://www.weberseeds.de/species/abrus_precatorius.htm Abrus precatorius seed (extremeclose-up)]