Bienenschäden durch Blattlausbekämpfungsaktionen

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Determination of benzoyl peroxide and benzoic acid levels by HPLC during wheat flour bleaching process

Freshly milled wheat flour has a pale yellow color due to its carotenoids content. Benzoyl peroxide is a bleaching agent typically used to give such flour a better appearance. This free-radical initiator promotes carotenoids oxidation, thereby producing less colored compounds, and benzoic acid is a main final product. Samples of wheat flour were treated with 150 ppm of benzoyl peroxide to begin a bleaching process, and then subjected to ethyl ether extraction at different intervals of time. Benzoyl peroxide and benzoic acid levels in these extracts were monitored by means of HPLC in individual experiences. The resulting concentration of benzoyl peroxide after 9 days of contact with the bleaching agent was 11 ppm, dropping afterward to nondetectable levels. A maximum value for benzoic acid of 16 ppm was found after 12 h of bleaching. Subsequently this level decreased continuously until reaching a residual value of 6 ppm after 3 months.     

Identification of F strain Mycoplasma gallisepticum isolates by detection of an immunoreactive protein

Commercial laying hens were examined microbiologically at necropsy 31 or 42 weeks after aerosol vaccination with the F strain of Mycoplasma gallisepticum (MG). Mycoplasma isolates were studied in Western blots probed with polyclonal antiserum raised in rabbits to F strain immunogen. The persistence of the vaccine strain was demonstrated by detection of a 75-kilodalton immunoreactive protein, which was present in all MG isolates and thought to be a unique marker of the F strain. Use of PCA-F to probe Western blots allowed simultaneous identification of non-MG isolates, non-F strains of MG, and the F strain of MG.     

Viral antibody studies of laboratory dogs with diarrheal disease

Viral antibody studies were done on laboratory dogs in an epizootic of gastrointestinal disease. Increased hemagglutination-inhibition antibody titers to a parvovirus (PV) antigenically related to feline panleukopenia virus were found in convalescent serum specimens of 78% (20/26) of the affected dogs and in 83% (5/6) of apparently healthy dogs. With one exception, all dogs tested had significant levels of hemagglutination-inhibition antibody to this PV. Similar increased antibody titers were found to feline panleukopenia virus. Also, neutralizing antibody responses were detected to the canine coronavirus in 24% (6/25) and canine herpesvirus in 45% (10/22) of the affected dogs. However, antibody titers did not increase to canine distemper virus, infectious canine hepatitis virus, canine parainfluenza virus, or minute virus of canines. Subsequent serotesting of the colony provided evidence that additional PV infections occurred in pups from each of 8 litters born 3 to 8 months after the epizootic. These findings indicated the continued presence of the PV for more than 1 year in the infected colony. Of 19 laboratory personnel who worked with the affected dogs, none, including 4 with a concurrent diarrheal disease, developed or had antibodies to the PV or canine coronavirus.