Virulence exaltation of Clostridium perfringens strains from bovines

Ten out of eighty-nine strains biochemically identified as Clostridium perfringens, isolated from bovine organs, were selected by their different results showed in toxigenicity test on mice. Those and the standard strains, ATCC types A, B, C, and D, had their virulence exalted through serial intramuscular inoculation into guinea pigs. Results showed that, for toxigenic strains (6), one or two passages were enough to cause exaltation, while for the atoxigenic (4), five or six inoculations were needed. Esterase electrophoresis of standard and isolated strains, with and without exaltation, was performed. Electrophoresis analysis permits the following conclusions: strains that do not show any clinical symptoms in mice, when exalted demonstrate decreased esterase activity; on the contrary, it is increased when correlated with animal symptoms.

Esterase electrophoresis of Clostridium perfringens bovine strains

Eighty-nine of 144 isolates of Clostridium perfringens abtained from 187 samples of 71 bovine in several Brazilian states were submitted to esterase electrophoresis for typing. Mobilites electrophoresis, as parameter, were settled down by isolates from ATCC pattern of types A, B, C, and D. Of the 89 isolates, 43 (48.3 per cent) were characterized as electrophoretic type A, 20 (22.5 per cent) as D, 18 (20.2 per cent) as C, and 3 (3.4 per cent) as B. Five (5.6 per cent) isolates did not identity with any type. Similarly esterase electrophoresis enabled the typing of 94.4 per cent of the isolates, demonstrating to be an appropriate method for animal sample analyses.

Toxigenicity characterization of Clostridium perfringens from bovine isolates

Clinical samples from 71 bovine from different Brazilian states were processed for the analysis of anaerobe organisms with emphasis on the isolation and characterization of Clostridium spp. From these eighty-nine Clostridium perfringens strains were recovered: 32 from liver, 19 from intestinal contents, 14 from kidney, 6 from rumen, 5 from nervous system, 4 from bone marrow, 2 from udder tract, blood, spleen and lung, and one from muscle. Four reference Clostridium perfringens types A, B, C, and D were used as controls in this study. All isolates were cultivated in appropriate media, and after centrifugation the supernatant and sediment were separated. From pure supernatant post exopolysaccharide (EPS) extraction, mouse toxigenicity tests were performed, determining protein and protein plus carbohydrate, respectively. ELISA was performed from sediments. The results showed that 51 (57.3 per cent) of the isolates were toxigenic to mice when inoculated by intraperitoneal route; bacteria from different organs had variable patterns of toxigenicity. Toxigenicity of EPS extracts was only expressed when protein concentration was 0.04 mg/mL and between 0.31 and 0.5 mg/mL for carbohydrate. Isolates were characterized as toxigenic when showing optimum protein and carbohydrate concentrations.

Purification and characterization of toxins from wheat isolates of Drechslera tritici-repentis, Bipolaris bicolor, and Bipolaris sorokiniana

Low molecular weight metabolites produced by Bipolaris bicolor, Bipolaris sorokiniana, and Drechslera tritici-repentis are considered to be toxins that facilitate disease in wheat cultivars. Several such toxins were isolated from these fungi. Electrophoresis demonstrated bands of proteins that reduce shoot inhibition in susceptible plants but not in resistant plants. Chlorophyll content was reduced during the first 10 hours of light in the susceptible plants and after 18 hours in the resistant plants. The enzyme beta-1,3-glucanase increased in the resistant plants after treatment with toxins, but in the susceptible plants this enzyme decreased compared to the control. This suggests that the toxin was a protein and the susceptible plants needed other mechanisms for induce resistance.