No abstract

No abstract

No abstract

The mycotoxins diacetoxyscirpenol, deoxynivalenol, and zearalenone, produced by Fusarium roseum, were found naturally occurring in mixed feed samples. In all cases analyzed, deoxynivalenol occurred together with zearalenone. The natural occurrence of zearalenone in sesame seed is reported for the first time. Strains of F. roseum isolated in various parts of the world from feed implicated in animal mycotoxicosis produced monoacetoxyscirpenol, diacetoxyscirpenol, deoxynivalenol, and zearalenone.

No abstract

No abstract

No abstract

The gene encoding an outer membrane lipoprotein (omlA) of Actinobacillus pleuropneumoniae serotype 5 was cloned, and the protein was expressed in Escherichia coli. One open reading frame of 1,104 bp was detected that encoded a protein (OmlA) with a predicted molecular mass of 40 kDa. A comparison with the omlA gene and the corresponding protein of A. pleuropneumoniae serotype 1 (G.-F. Gerlach, C. Anderson, S. Klashinsky, A. Rossi-Kampos, A. A. Potter, and P. J. Wilson, Infect. Immun. 61:565-572, 1993) revealed that the nucleic acid sequences had an overall sequence identity of 62.9% and the deduced amino acid sequences showed a sequence agreement of 57.3%. Both proteins were antigenically distinct. In a Western blot (immunoblot) analysis using a specific antiserum against A. pleuropneumoniae serotype 5 OmlA, a homologous protein was detected in the reference strains of A. pleuropneumoniae serotypes 5A, 5B, and 10. Pigs immunized with this recombinant protein were protected from death in an aerosol challenge experiment with an A. pleuropneumoniae serotype 5 isolate. Actinobacillus pleuropneumoniae is a highly infectious porcine respiratory tract pathogen (22). The disease caused by this bacterium is encountered worldwide and frequently causes severe losses in infected herds (21). Infected animals develop disease symptoms ranging from acute fibrinous pneumonia and pleuritis with high mortality to chronic lung lesions resulting in reduced growth rates (22). Pigs which survive an infection develop a protective immune response but can still be carriers of the pathogen (22). The rapid onset and severity of disease mean that losses may occur before antibiotic therapy has time to become effective. Attempts to immunize against A. pleuropneumoniae disease have been hampered by the occurrence of two biotypes and more than 14 serotypes (2, 6, 10-14, 16) and the lack of reliable cross-protection (9). It has been hypothesized that a cross-protective immune response might be achievable by immunization with a mixture of serotype-specific antigens that are recognized by convalescent sera (3). Recently, we were able to show that two recombinant proteins could protect pigs from death in an A. pleuropneumoniae serotype 7 challenge (17). One of these antigens was a truncated RTX toxin, and the other was an iron-regulated transferrin-binding protein. However, no cross-protection against A. pleuropneumoniae serotype 1 infection was observed (17). In order to achieve protection against A. pleuropneumoniae serotype 1 (3), we were successful in cloning and expressing a protective outer membrane lipoprotein (OmlA) of A. pleuropneumoniae serotype 1. In an A. pleuropneumoniae serotype 1 challenge experiment, all animals immunized with the recombinant OmlA were protected from death (3). However, antiserum raised against the transferrin-binding proteins of A. pleuropneumoniae serotypes