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Pesticidal activity and receptor-binding properties of Bacillus thuringiensis toxins to rice leaf folders, Cnaphalocrocis medinalis and Marasmia patnalis, were investigated. Saturation and competition binding experiments were done with iodine (1251)-labeled Bt proteins and brush border membrane vesicles prepared from the midgut of C. medinalis and M. patnalis. The results show saturable, specific, and high-affinity binding of all toxins except Cry2A toxin. Cry1Aa and Cry2A toxins were bound with low affinity but with high binding site concentration. Heterologous competition experiments showed that Cry1Aa, Cry1Ab, and Cry1Ac recognized or shared the same binding site that is different from the binding site for Cry2A toxin. Iodine (125I)-labeled Cry1Ac and Cry1Ab toxins were used in ligand blot experiments to detect specific binding proteins in brush border membrane vesicles of C. medinalis and M. patnalis. Cry1Ab toxin protein binds to 205-kDa and 200-kDa proteins respectively in case of C. medinalis and M. patnalis. The apparent molecular mass of the protein bound to labeled Cry1Ac toxins was identified as a 120-kDa protein in both C. medinalis and M. patnalis. [ABSTRACT FROM AUTHOR]

Induced auto-allergic lesions in the submandibular glands of rats were studied by immunofluorescence. Direct staining with a goat anti-rat IgG conjugate was negative. Indirect immunofluorescence revealed a high incidence of anti-salivary -duct antibodies in sera from both control and experimental groups. In individual rats, no relationship was found between the presence or absence of serum anti-salivary antibodies and the presence or absence of salivary auto-allergic lesion. We conclude that the antibodies demonstrated do not play a role in the pathogenesis of the disease. [ABSTRACT FROM AUTHOR]

Parotid traumatization resulted in significant hyperamylasemia at 2 and 18 h, but resolved by 72 h after surgery. Traumatization of the exorbital lacrimal gland did not result in hyperamylasemia. Parotid duct ligation led to significantly increased amylase levels at 24 and 48 h, but resolved by 72 h. [ABSTRACT FROM AUTHOR]

The Bacillus thuringiensis insecticidal crystal protein CryllA has both high mosquito activity and gypsy moth activity; in contrast CryllB, which is 87% homologous, displays no mosquito activity and has a threefold lower gypsy moth activity. The regions responsible for specificity against gypsy moth (Lymantria dispar) and mosquito (Aedes aegypti) larvae were located by introducing Mlul and Xhol sites into homologous positions within the putative domain II of both cryllA and cryllB genes, which divided almost equally the respective second domains into three regions. Taking advantage of naturally occurring Nhel and Narl sites that border the putative domain II, a set of seven chimeric proteins were produced by exchanging all combinations of those regions between CryllA and CryllB. Analysis of the toxicity of these chimeric proteins demonstrated that the lepidopteran and dipteran specificity regions of CryllA were not colinear. While the specificity region of CryllA against mosquito larvae involved region 1 and probably also region 2, the specificity region of CryllA against gypsy moth larvae was located within region 2. [ABSTRACT FROM AUTHOR]

Presents a study which examined the proposed nomenclature based on hierarchical clustering for the Bacillus thuringiensis pesticidal crystal proteins. Background and history of pesticidal crystal proteins; Details on the proposed nomenclature; Robustness of the nomenclature.

Presents a study which determined the gene expression, structure and mechanism of Bacillus thuringiensis, a supplement to synthetic chemical pesticide application. Characteristics, ecology and prevalence of B. thuringiensis; Genetics and molecular biology; Toxin structure and biotechnology of B. thuringiensis.