Jequirity

The Jequirity, also called Crab's Eye, Rosary Pea, 'John Crow' Bead, Precatory bean or Indian Licorice (Abrus precatorius), is a legume with long, pinnate-leafleted leaves. Their seeds are often used as beads and in percussion instruments. The seed is highly poisonous but is unlikely to harm if swallowed raw and unbroken, as they have a hard seed coat.

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  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 facillitates 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).

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, while 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