Toxicity of Protease-Resistant Domains from the Delta-Endotoxin of \u3ci\u3eBacillus thuringiensis\u3c/i\u3e subsp. \u3ci\u3eisraelensis\u3c/i\u3e in \u3ci\u3eCulex quinquefasciatus\u3c/i\u3e and \u3ci\u3eAedes aegypti\u3c/i\u3e Bioassays

The mosquitocidal glycoprotein endotoxin of Bacillus thuringiensis subsp. israelensis was digested with chymotrypsin to yield protease-resistant domains which were then separated from smaller protease digestion products by high-performance liquid chromatography. Once purified, the domains no longer bound wheat germ agglutinin, a lectin which binds N-acetylglucosamine (GlcNAc) and GlcNAc oligomers. Purified protease-resistant domains were as toxic for Culex quinquefasciatus larvae as intact solubilized toxin. In separate experiments, the toxicity of chymotrypsin-digested endotoxin for Aedes aegypti larvae was reduced fivefold or more. A model is presented in which GlcNAc-containing oligosaccharides are required for toxicity for A. aegypti larvae but not C. quinquefasciatus larvae

Pathogenicity of \u3ci\u3eEscherichia coli\u3c/i\u3e O157:H7 in the Intestines of Neonatal Calves

Cattle are an important reservoir of Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains, foodborne pathogens that cause hemorrhagic colitis and hemolytic uremic syndrome in humans. EHEC O157:H7 strains are not pathogenic in calves \u3e3 weeks old. Our objective was to determine if EHEC O157:H7 strains are pathogenic in neonatal calves. Calves(A/E) lesions in both the large and small intestines by 18 h postinoculation. The severity of diarrhea and inflammation, and also the frequency and extent of A/E lesions, increased by 3 days postinoculation. We conclude that EHEC O157:H7 strains are pathogenic in neonatal calves. The neonatal calf model is relevant for studying the pathogenesis of EHEC O157:H7 infections in cattle. It should also be useful for identifying ways to reduce EHEC O157:H7 infections in cattle and thus reduce the risk of EHEC O157:H7 disease in humans

EC90-219 1990 Nebraska Swine Report

This 1990 Nebraska Swine Report was prepared by the staff in Animal Science and cooperating departments for use in the Extension and Teaching programs at the University of Nebraska-Lincoln. Authors from the following areas contributed to this publication: Swine Nutrition, swine diseases, pathology, economics, engineering, swine breeding, meats, agronomy, and diagnostic laboratory. It covers the following areas: breeding, disease control, feeding, nutrition, economics, housing and meats