CRY14Ab1 is a crystal protein from Bacillus thuringiensis related to the other crystal proteins CRY1A, CRY3A and CRY4A. Structurally, the protein contains three domains. The protein has been demonstrated to have nematicidal activity against Caenorhabditis elegans, Panagrellus redivivus, Nippostrongylus brasiliensis, Distolabrellus veechi, Meloidogyne spp. (root knot nematodes), Rotylenchulus reniformis (reniform nematode), Hopiolaimus spp. (Lance nematode), Pratylenchus spp. and Heterodera glycines (soybean cyst nematode). The protein is thought to act in the intestine of nematodes. During feeding assays with C. elegans, the symptoms included constriction and thinning of intestinal cells, shrinkage of the gut, vacuolization and a degenerative appearance. Due to its relation to other crystal proteins, it is thought that CRY14A may also have insecticidal properties as well.