Significance of β2‐Toxigenic Clostridium perfringens Infections in Animals and Their Predisposing Factors – A Review

The novel β2‐toxin of Clostridium perfringens has recently been described as the cause of enteric diseases in animals. The biological activity of β2‐toxin is similar to that of the β1‐toxin with a possibly weaker cytotoxic activity. However, the production of β2‐toxin in vitro is not seen in all β2‐toxin‐gene (cpb2)‐positive C. perfringens strains, and to deduce a clinical importance solely from the detection of cpb2 is difficult. Detection of cpb2‐positive C. perfringens from various animal species with and without enteric diseases demonstrates the wide distribution of cpb2 in nature, and the presence of cpb2 gene is therefore not considered a risk by itself. Predisposing factors like low trypsin activity in the intestinal tract, antibiotic and/or antiphlogistic treatment or changes in diet can result in the selection of β2‐toxigenic C. perfringens which may lead to enteritis or enterotoxaemia.     

Gibbsite and halloysite decomposition in strongly acid podzolic soils developed from granitic saprolite of the Bayerischer Wald

The present study reports the occurrence of gibbsite and halloysite in soils derived from granitic saprolites and from glacial deposits formed from granitic saprolites of the Bayerischer Wald (Germany). Both minerals are common in soils of this area. They were formed in the initial stages of weathering, most probably before the Pleistocene and in a warmer climate. Under present conditions halloysite and gibbsite are unstable in the surface soils, as indicated by a decrease in gibbsite concentration towards the surface and by an undersaturation of the equilibrium soil solution with respect to both minerals. It is assumed that the strongly acid conditions and the high concentration of organic compounds in the surface horizons lead to dissolution of gibbsite and possibly to transformation of halloysite to kaolinite.     

Processes of collating a European fisheries database to meet the objectives of the European Union Water Framework Directive

Abstract  FIsh Database of European Streams, a common database for the FAME project, was merged using existing data on electric fishing and environmental data. FIsh Database of European Stream is a relational database with eight tables. Metrics based on classification of fish species into guilds were calculated, and provided in separate tables. FIsh Database of European Stream contained information about 150 freshwater fish species, from 12 countries, 17 ecoregions, 40 main river regions, 2651 rivers and 8228 sites. Examples of data coverage and use are given. Relationships between environmental variables were illustrated using principal component analysis, which resulted in three environmental components – latitude, size and altitude. Environmental component scores were correlated with fish metrics used in the European Fish Index. Results exemplify how fish guilds reflect gradients in environmental variation. Benefits and problems concerning standardisation and data availability at the global level are discussed.     

Literarische Berichte

Ohne Zusammenfassung     

The joint action of fungicides in mixtures: comparison of two methods for synergy calculation

Two methods for evaluating the joint action of fungicides in mixtures were analysed. In order to obtain a relatively rapid answer on the type of interaction between fungicides in a mixture (additivity, synergism or antagonism), one can apply the Abbott formula to data on fungus survival. Tests with this method will not be accurate at high effective dose values. A more accurate determination of the joint action of fungicides can be made by the Wadley method, applied to data on effective doses. This involves more experimental work than the Abbott method. Optimization of mixing ratios of fungicides required a set of experimental data on effective doses with several mixing ratios.     

The detection of obligate anaerobic bacteria in udder secretions of dry cattle with mastitis during summer: a comparison between gas-liquid chromatography and bacteriological culturing methods

Udder secretions sampled during the summer in 1984 and 1985 from mastitic quarters of 51 non-lactating cattle, mainly heifers less than 2 years of age, were examined bacteriologically for the presence of (facultative) aerobic and obligate anaerobic bacteria (OAB) and by gas-liquid chromatography (GLC) in order to detect volatile fatty acids (VFA), metabolic end-products of OAB. Forty-nine samples yielded positive cultures and in 20 cases these were mixtures of (facultative) aerobes and OAB. Only two specimens appeared to be sterile and from one specimen only were OAB cultured. Corynebacterium pyogenes was isolated from 35% of the cases and Peptococcus indolicus and Fusobacterium necrophorum from 31 and 22%, respectively. In most specimens (19/21) which yielded OAB after culturing, VFA (C3-C6) could be detected by GLC. Detection of VFA in summer mastitis secretions appeared to be a useful technique to evaluate the importance and association of OAB with summer mastitis. Because samples can be easily collected and stored at -20 degrees C, this is especially advantageous in situations where adequate facilities for the isolation of OAB are not readily available.