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991.
1987~1992年连续6年研究结果表明,白跗平腹小蜂Anastatusalbitarsis对马尾松毛虫Dendrolimuspunctatus、柳杉毛虫Dendrolimuslatipennis、水青蛾Actiasseteneningpoana等13种主要森林害虫卵有较明显的抑制作用。在林间,该蜂对马尾松毛虫第1、2代卵的自然抑制力分别力16.55%和22.29%,对柳杉毛虫越冬代卵的自然抑制力为23.45%;对水青蛾第1、2代卵的抑制力分别力5.49%和2.63%;在林间,人为释放白跗平腹小蜂对第1代马尾松毛虫卵的校正抑制力为33.5%,在室内12.3~28℃范围内,每头雌峰对马尾松毛虫、水青蛾和柞蚕剖腹卵的日破坏数(寄生数)分别力15、18和26粒,一生破坏数分别为56、91和208粒。即使虫卵即将孵化,该峰同样亦能寄生,并羽化出正常的子代白跗平腹小蜂。  相似文献   
992.
Pasteurella multocida toxin (PMT) is the major virulence factor in Progressive Atrophic Rhinitis of swine. Other workers' previous findings that PMT was mitogenic for 3T3 fibroblasts, were confirmed in the present study. In addition, PMT stimulated 3T3 cells to release IL-6, but IL-1 alpha or TNF alpha were not detected in fibroblast supernatants sampled 24, 48, or 72 h after stimulation. In view of the role of IL-6 in osteoclastic bone resorption, these findings provide a new working hypothesis for investigations into the molecular pathogenesis of this important disease.  相似文献   
993.
Based on the Chiang's method, the life table for cats was constructed from the death data of 3936 cats. They died in the Kanto area and were buried in an animal cemetery in Tokyo from June 1981 through May 1982. This life table seems to be the first one for domestic pet cats. The expectation of life for cats was 4.2 years at age 0, 5.0 years at age 1, 5.4 years at age 4, 5.3 years at age 5, 3.5 years at age 10, and 2.2 years at age 15. The maximum age at death was 22 years. From age 0 to age 5, the probability of dying for cats was higher than that for dogs, but over 6 years of age it seemed that Gompertz's equation was applicable to this life table for cats. From these results, if the probability of dying for cats at early ages decreases, the fundamental pattern of dying curve for cats seems to be a similar figure of dogs. The life table was constructed for different breeds and localities. Comparing the expectation of life at age 1 (e1) of the two populations divided by breeds or localities, there was significant difference in the e1 among different localities but not among different breeds. These facts suggest the existence of some factors which may influence the life span of cats among different localities.  相似文献   
994.
M. Hühn 《Plant Breeding》1992,109(1):28-34
In many fields of application in plant breeding and crop science, ratios of two component traits X and Y are of interest (harvest index in cereals, leaf-to-stem ratio in forage legumes, height-to-diameter ratio in forest trees etc.). When selection is practised on the ratio X/Y of two traits X and Y, the experimenter may be interested in the resulting changes of both trait means. Based on improved approximations for the covariances between X and X/Y and between Y and X/Y and for the variance of X/Y the changes in the means of X and Y can be predicted by applying the regression approach from conventional selection theory. Explicit expressions for these correlated responses in X and Y when selection is practised on their ratio X/Y are derived and discussed. The different outcomes (decrease, zero change or increase) for the selection pressures on X and Y are characterized by phenotypic coefficients of variation of X and Y, phenotypic and genotypic correlations between X and Y and heritabilities of X and Y.  相似文献   
995.
The attenuation of a Babesia bovis strain depends on its protease content. The present work evaluates this parameter on a virulent strain, before and after attenuation by quick passages on splenectomized calves. The protease activity at different pH values was determined in protein fractions from the blood of calves. The enzymatic test showed marked differences between the protease content of both substrains.  相似文献   
996.
Lupus-Type "Anticoagulant" in a Dog With Hemolysis and Thrombosis   总被引:1,自引:1,他引:0  
A circulating anticoagulant was detected in a 2-year-old Chesapeake Bay Retriever with hemolytic anemia, nephrotic syndrome, thrombocytopenia, polyarthropathy, and pulmonary thromboembolism. A persistent prolongation of the activated partial thromboplastin time (aPTT) was detected, and it did not correct with repeated administration of fresh frozen plasma. The aPTT was still prolonged, with a 1:1 mixture of patient's plasma and normal dog plasma in vitro, suggesting the presence of a circulating inhibitor. Results of assays to characterize the inhibitor were compatible with those described for the lupus anticoagulant in human patients with systemic lupus erythematosus. Paradoxically, patients having the lupus anticoagulant are at increased risk for thrombosis. Pulmonary thromboembolism has been described as a frequent complication of immune-mediated hemolytic anemia in the dog, and the presence of a circulating anticoagulant should be considered as a potential mechanism.  相似文献   
997.
Bovine semen samples spiked with bovine herpesvirus 1 (BHV-1) were used to compare dot blot hybridization, polymerase chain reaction (PCR), and virus isolation for detection of BHV-1 in bovine semen. The PCR amplification used primers targeting the BHV-1 thymidine kinase gene and a nucleic acid releasing cocktail (GeneReleaser); the PCR product was used as the DNA probe in dot blot hybridization; virus isolation was done in primary bovine fetal testis (BFT) cell cultures. Semen diluted 1:20 in tissue culture medium had the least cytotoxicity and inhibition of viral cytopathic effects in BFT cells, allowing detection of 1 TCID50/100 microL of BHV-1 suspension by virus isolation. The presence of foreign DNA such as bovine sperm DNA or salmon sperm DNA increased the sensitivity of dot blot hybridization in detecting BHV-1, allowing detection of 20,000 TCID50/100 microL of neat semen. The inhibition of PCR amplification of BHV-1 DNA in bovine semen was eliminated by diluting the samples 1:20 in tissue culture medium. The best PCR amplification was obtained when semen was diluted 1:20 and when a reaction buffer of pH 9.0, with 1.0 mM MgCl2 was used. Under these conditions, the PCR followed by ethidium bromide staining of agarose gels could detect 1 TCID20/100 microL of sample, whereas PCR followed by Southern blot hybridization could detect 0.01 TCID50/100 microL of sample.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
998.
999.
The use of a cholecystostomy catheter for temporary bile diversion was investigated in four cats with experimentally induced extrahepatic bile duct obstruction. Eighteen days after ligation of the common bile duct, a 6.5 F accordion catheter was placed in the gallbladder with a 22 g Hawkins needle-guide system through a paracostal incision. Biochemical parameters and fasting serum bile acids were monitored for 16 days. There were significant decreases in mean total bilirubin, aspartate aminotransferase, and fasting serum bile acids within 72 hours of bile diversion, and in mean alanine aminotransferase within 96 hours. Attitude and appetite improved, and the catheter was tolerated well. Positive bile cultures developed in three cats. Histologic changes in the gallbladder included mucosal ulcerations, a mixed inflammatory cellular infiltration, and fibrosis of the submucosa.  相似文献   
1000.
The severity of charcoal root disease of conifer seedlings (Abies concolor, A. magnified, Pinus jeffreyi, P. lambertiana, and Pseudotsuga menziesii) was a power function of the sclerotial density of the fungus (Macrophomina phaseolina) in nursery soil.  相似文献   
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