Effets de divers herbicides sur la croissance mycélienne de souches de Botrytis cinerea pers et de Penicillium expansum Link, sensibles ou résistantes à certains fongicides

Effects of various herbicides on mycelial growth of strains of Botrytis cinerea. Pers. and Pénicillium expansum Link, sensitive or resistant to certain fungicides Of seventy herbicides tested, thirty-eight were slightly toxic to B. cinerea (CI50, concentration giving 50% inhibition of the speed of mycelial growth, exceeding or equal to 100g of herbicide/ml of nutrient solution) and, of those, ten had no effect even at 1000 g/ml. The most active products (CI50 less than 10 g/ml) were Chlorthiamid, dichlobénil, nitrofen, propyzamide and phenolic derivatives (DNOC, ioxynil, PCP). In most cases P. expansum was less sensitive than B. cinerea except to endothal, propachlor, prynachlor and certain substituted ureas. Strains resistant to the benzimidazole fungicides (carbendazim, thiabendazole etc.) show increased sensitivity to certain carbamade herbicides (barban, chlorbufam etc.), this indicates the existence of a negative cross resistance between these groups of antimitotic pesticides. Strains resistant to the cyclic-imide fungicides (iprodionc, procymidone, vinclozolin) and to various aromatic compounds (biphenyl. chloroneb, dicloran etc.) may also be resistant to bipyridilium, dinitroanilinc and diphenylethcr herbicides, to chlorthamid. dichlobénil and oxadiazon. This cross resistance between pesticides with different biochemical modes of action has yet to be explained.     

Comparison of DNA probe test and cultivation methods for detection of Mycobacterium avium subsp paratuberculosis in caprine and ovine faeces

OBJECTIVE: To compare a DNA probe test with two cultivation methods for the detection of Mycobacterium avium subsp paratuberculosis in goat and sheep faeces. DESIGN: Comparison of the results of the three methods with histological examination as the reference standard. PROCEDURE: Faecal specimens were obtained from goats and sheep originating from flocks known to be affected with paratuberculosis and tested for Mycobacterium avium subsp paratuberculosis with a DNA probe test and two cultivation methods (old conventional culture and new double incubation method in Herrold's and Lowenstein-Jensen medium). RESULTS: In goats, the sensitivity of the various tests were for the DNA probe test 17.2%, for the double incubation culture method 25.4% and for the old conventional culture method 22.8% using the histopathological results as reference. In sheep the sensitivity of the various tests were for the DNA probe test 13.2%, for the double incubation culture method 8.8% and for the old conventional culture method 5.9% using the histopathological results as reference. The specificity of the above tests was 100% in goats and sheep and the specificity of the double incubation culture method in goats was 91%. CONCLUSIONS: The DNA probe test is a rapid and specific test that could be used in a control program if the sensitivity of the test were improved and possibly in combination with another test.     

Mitotic instability in Aspergillus nidulans caused by the fungicides iprodione,procymidone and vinclozolin

The fungicides iprodione, procymidone and vinclozolin were found to increase greatly the frequency of mitotic recombination in diploid colonies of Aspergillus niduluns. Although generally more potent, these fungicides do not appear to differ in their activity from members of a previously suggested ?aromatic hydrocarbon group’? with which they should be classified in this context.     

Natural and experimental infection of rodents (Rattus norvegicus) with Salmonella gallinarum]

Thirty five (35) rats (Rattus norvegicus) were trapped in the area of four egg producing poultry farms and were examined for Salmonella spp., micro-biologically. The samples were taken from liver, spleen and intestinal content. Cultures were made directly in MacConkey Agar, in Selenite broth and Rappaport Vassiliadis at 37 degrees C and 43 degrees C. Five strains of S. gallinarum and one strain of Salmonella subgroup II were isolated from the intestinal content of six rats. An experimental study was also carried out. Ten rats Rattus norvegicus were trapped near poultry farms of N. Greece. No Salmonella could be detected in their feces when examined three times by the Selenite 37 degrees C and Rappaport-Vassiliadis 37 degrees C methods. The rats were orally infected with an 18 hours culture of S. gallinarum (1 x 10(9)/ml microorganisms). One hundred and sixty samples of feces were periodically collected and examined for the isolation of the microorganism by the methods mentioned above. Although not any clinical sign of a disease was noticed, S. gallinarum was isolated from their feces up to 121 days post infection.     

Salmonella infection sources in poultry flocks in northern Greece]

From 10 egg production poultry farms 1516 samples were collected and examined for the presence of salmonella. The samples were: 201 chicken, 36 sparrows, 35 rats, 35 pools of 20 flies each, 450 eggs, 60 mattresses, 188 feces, 425 feedstuffs and 86 water samples. Salmonellae were isolated only from 163 (10.8%) samples. From the 146 (89.6%) of these S. gallinarum was isolated. From the rest 17 (10.4%) the following mobile salmonella strains were isolated: two strains of S. virchow and Salmonella of subgroup II, four strains of S. typhimurium var. Copenhagen, seven strains of S. Livingstone, one S. enteritidis and one S. infantis The S. gallinarum was isolated from dead or sick chicken (46%), eggs (10.4%), rats Rattus norvegicus (14.3%) and mattresses 1.6%. The mobile salmonellae were isolated from feedstuffs (2%), flies (14.3%), rats (2.8%), feces (1%). From the present study, it seems that rats, chicken and eggs are important for the salmonella dissemination.     

Tracking the evolution of a hydrothermal event plume with a RAFOS neutrally buoyant drifter

The migration and evolution of a deep ocean hydrothermal event plume were tracked with a neutrally buoyant RAFOS float. The float remained entrained in the plume for 60 days, and the plume vorticity was calculated directly from the anticyclonic motion of the float. Concentrations of suspended particles, particulate iron, and dissolved manganese in the plume did not decay significantly during the 60 days, which indicates that event plumes would be easily detectable a year after formation.     

A Salmonella abortusovis inactivated vaccine protects mice from abortion after challenge.

Two types of Salmonella abortusovis vaccines were prepared, one with aluminium hydroxide (vaccine A) and the other with water in oil (vaccine B) adjuvants. They were compared in a pregnant mouse model, aiming at protecting them from abortions after challenge with a virulent strain of S. abortusovis. The protection for vaccine A was from 74% to 77.6% and that for vaccine B from 71% to 79.6%. Abortions occurred 5-10 days post challenge and S. abortusovis was isolated from all aborted fetuses and from the liver and the spleen of their mothers at the end of the experiment (18 days post challenge). The presence of salmonella in the liver and the spleen of vaccinated non-pregnant but challenged mice was studied in a separate experiment. The bacterium was isolated from one out of 12 vaccinated mice 6 days post challenge as well as from the six controls.