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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.  相似文献   
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An enzyme immunoassay that utilizes antigen bound to a matrix which can be removed from the substrate to stop development is described. The assay which is performed in glass or plastic disposable tubes uses Gel-Bond film strips for attachment of antigen. The only equipment requirements are a rotary shaker and a spectrophotometer (optional). The antigen coated strips are passed through a series of tubes containing test serum, wash solution, antibody-enzyme conjugate, wash solution and substrate-chromogen taking about 45 minutes to perform. In testing sera with or without antibody to Brucella abortus a very high correlation existed between same day tests and tests performed over several days as well as with data on the same sera obtained by an enzyme immunoassay in a microtiter format.  相似文献   
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Salivary glands from males of 3 Dermacentor species (D andersoni, D variabilis and D occidentalis) that were infected with either the Virginia or Idaho isolate of Anaplasma marginale as nymphs or adults were examined for colonies of A marginale by use of light and electron microscopy. Prior to dissection of salivary glands, exposed ticks were held at 25 C for 15 to 18 days, followed by a 3-day incubation at 37 C. Ticks of 2 species transmitted A marginale to calves; the third tick species was confirmed infected by demonstration of typical colonies in tick gut cells, but transmission was not attempted; Colonies of A marginale were seen with light microscopy in salivary glands of all 3 species of ticks; they were located in acinar cells that contained simple granules. Colonies varied morphologically from small, compact ones to larger structures that contained distinct organisms and often were adjacent to the host cell nucleus. Electron microscopy confirmed that the colonies were rickettsial organisms. Morphologic features of A marginale varied and included reticulated forms, forms with electron-dense centers, and small particles; these various forms were similar to those described previously in midgut epithelial cells of ticks. We believe that the organism seen within tick salivary glands may replicate in the glands before its transmission to the vertebrate host.  相似文献   
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The prevalance of Anaplasma marginale-infected cows, as determined by use of the modified rapid card agglutination (MRCA) test, was measured during a 4-year period (1980-1983). The prevalence of A marginale-infected cows, defined as positive reactors on the MRCA test, remained constant (31%-37%). The apparent incidence of A marginale transmission to susceptible cows was approximately 7% from 1980 to 1981, 8% from 1981 to 1982, and no transmission from 1982 to 1983. The occasional MRCA-positive cow became negative on the MRCA test, and 1 cow was determined to be free of A marginale infection by subinoculation of 100 ml of the cow's blood into a susceptible, splenectomized calf. Dermacentor andersoni, a known vector of A marginale, was often found on the cattle and in their environment. However, A marginale was not transmitted to susceptible, splenectomized calves, using collected ticks. Of 56 calves born to MRCA-positive cows, 82% were MRCA-positive within the first 3 months of life. These calves converted to MRCA-negative status and were determined to be free of A marginale infection by subinoculation of their blood into susceptible, splenectomized calves, indicating the passive transfer of colostral antibodies.  相似文献   
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Optimal reagent parameters for a haemolysis in gel test for detection of bovine anti-Brucella abortus antibody were established. Using an alkali-treated crude lipopolysaccharide antigen attached to J-negative bovine erythrocytes, 0.125 mg of antigen, 0.1 ml of erythrocytes and 0.4 ml of guinea pig complement were required to perform 15 tests with appropriate serum controls. The haemolysis in gel test and an IgM radioimmunoassay (RIA) procedure were compared for their ability to detect the onset of increased serum antibody levels and antibody levels in sera diluted to extinction. While the RIA was more sensitive in amount of antibody detected, the haemolysis in gel test was equally able to detect initiation of antibody synthesis.  相似文献   
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