In vitro larval migration and kinetics of exsheathment of Haemonchus contortus larvae exposed to four tropical tanniniferous plant extracts     

Alonso-Díaz MA  Torres-Acosta JF  Sandoval-Castro CA  Aguilar-Caballero AJ  Hoste H 《Veterinary parasitology》2008,153(3-4):313-319

As for some temperate forage, some tropical tanniniferous plants (TTP) from browsing might represent an alternative to chemical anthelmintic. The anthelmintic effect of four TTP (Acacia pennatula, Lysiloma latisiliquum, Piscidia piscipula, Leucaena leucocephala) on Haemonchus contortus was measured using two in vitro assays. First, the effects of increasing concentrations of lyophilized extracts (150, 300, 600, 1200 microg/ml PBS) were tested on H. contortus larvae (L(3)) using the larval migration inhibition (LMI) test. An inhibitor of tannin, polyvinyl polypyrrolidone (PVPP), was used to verify whether tannins were responsible for the AH effect. Secondly, the effects of extracts on larval exsheathment were examined. Larvae (L(3)) were in contact with extracts (1200 microg/ml) for 3h, and then were exposed to an artificial exsheathment procedure with observations of the process at 10 min intervals. A general lineal model (GLM) test was used to determine the dose effect in the LMI test and the difference of the percentage of exsheathed larvae between the control and the treatment groups. A Kruskal Wallis test was used to determine the effect of PVPP on LMI results. The LMI test showed a dose-dependent anthelmintic effect for A. pennatula, L. latisiliquum and L. leucocephala (P<0.01), which disappeared after PVPP addition, confirming the role of tannins. No effect was found for P. piscipula on H. contortus in the LMI test. However, all four plant extracts interfered with the process of L(3) exsheathment which might be involved as a mechanism of action of tannins on H. contortus larvae. A. pennatula, L. latisiliquum and L. leucocephala could be used as an anthelmintic for the control of H. contortus after confirmation based on in vivo studies.  相似文献   

The Current State of Solar Modeling     

J Christensen-Dalsgaard  W Dappen  SV Ajukov  ER Anderson  HM Antia  S Basu  VA Baturin  G Berthomieu  B Chaboyer  SM Chitre  AN Cox  P Demarque  J Donatowicz  WA Dziembowski  M Gabriel  DO Gough  DB Guenther  JA Guzik  JW Harvey  F Hill  G Houdek  CA Iglesias  AG Kosovichev  JW Leibacher  P Morel  CR Proffitt  J Provost  J Reiter  EJ Rhodes  FJ Rogers  IW Roxburgh  MJ Thompson  RK Ulrich 《Science (New York, N.Y.)》1996,272(5266):1286-1292

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.  相似文献   

Modeling the Exchanges of Energy, Water, and Carbon Between Continents and the Atmosphere   总被引：19，自引：0，他引：19  

PJ Sellers  RE Dickinson  DA Randall  AK Betts  FG Hall  JA Berry  GJ Collatz  AS Denning  HA Mooney  CA Nobre  N Sato  CB Field  A Henderson-Sellers 《Science (New York, N.Y.)》1997,275(5299):502-509

Atmospheric general circulation models used for climate simulation and weather forecasting require the fluxes of radiation, heat, water vapor, and momentum across the land-atmosphere interface to be specified. These fluxes are calculated by submodels called land surface parameterizations. Over the last 20 years, these parameterizations have evolved from simple, unrealistic schemes into credible representations of the global soil-vegetation-atmosphere transfer system as advances in plant physiological and hydrological research, advances in satellite data interpretation, and the results of large-scale field experiments have been exploited. Some modern schemes incorporate biogeochemical and ecological knowledge and, when coupled with advanced climate and ocean models, will be capable of modeling the biological and physical responses of the Earth system to global change, for example, increasing atmospheric carbon dioxide.  相似文献   

Experimental tunicamycin toxicity in cattle, sheep and pigs     

CA BOURKE  MJ CARRIGAN 《Australian veterinary journal》1993,70(5):188-189

  相似文献   

Systemic Immunosuppression by Methylprednisolone and Pregnancy Rates in Goats Undergoing the Transfer of Cloned Embryos     

C Feltrin  CA Cooper  N Mohamad‐Fauzi  VHV Rodrigues  LH Aguiar  S Gaudencio‐Neto  LT Martins  CEM Calderón  AS Morais  IS Carneiro  TM Almeida  ING Silva  JL Rodrigues  EA Maga  JD Murray  AB Libório  LR Bertolini  M Bertolini 《Reproduction in domestic animals》2014,49(4):648-656

The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona‐free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre‐treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona‐free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo‐ vs in vitro‐matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona‐free and zona‐intact goat cloned embryos.  相似文献   

Detection and Characterization of the Cumulene Carbenes H2C5 and H2C6     

MC McCarthy  MJ Travers  A Kovacs  W Chen  SE Novick  CA Gottlieb  P Thaddeus 《Science (New York, N.Y.)》1997,275(5299):518-520

Two cumulene carbenes, H2C5 and H2C6, were detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. Their rotational and leading centrifugal distortion constants were determined with high accuracy, such that the entire radio spectrum can now be calculated. Like the known carbenes H2C3 and H2C4, both molecules have singlet electronic ground states and linear carbon-chain backbones. They can be produced in sufficiently high concentrations in the laboratory that their electronic spectra, expected to lie in the visible, should be readily detectable by laser spectroscopy. The microwave spectra of other, more exotic isomers may be detectable as well.  相似文献   

ELISA在苏云金杆菌杀虫蛋白毒素检测中的应用及新进展     

吴瑞华李国勋  冯书亮王容燕王金耀  曹伟平杜立新 陈丹 《华北农学报》2007,22(B10):216-219

苏云金杆菌是目前应用较广泛的生物杀虫细菌之一，其产生的杀虫蛋白毒素是主要的杀虫成分，目前对苏云金杆菌的毒力和杀虫蛋白毒素的检测主要采用生物测定、SDS-PAGE等方法，但这些方法的灵敏度较差。本文综述了酶联免疫吸附分析法在苏云金杆菌蛋白毒素检测中的应用，以及在检测中采用的ELISA的类型和基本原理，并对其应用前景进行了展望。  相似文献   

球孢白僵菌生长及毒力影响因子的研究进展   总被引：1，自引：0，他引：1  

陆晴董建臻  曹伟平王金耀 冯书亮 《华北农学报》2007,22(B10):58-61

随着害虫综合治理的提出，昆虫病原真菌在防治农林害虫上的应用日趋广泛，白僵菌是世界各国研究应用最多的真菌杀虫剂。从白僵菌生长所需的营养、温湿度条件等方面的研究进展进行阐述，总结了提高菌株生长水平和杀虫效果的主要措施，以期对今后白僵菌的培养及应用提供参考。  相似文献   

Comparing the sensitivity of two in vitro assays to evaluate the anthelmintic activity of tropical tannin rich plant extracts against Haemonchus contortus     

Alonso-Díaz MA  Torres-Acosta JF  Sandoval-Castro CA  Hoste H 《Veterinary parasitology》2011,181(2-4):360-364

The present trial aimed at comparing the sensitivity of two in vitro methods, i.e. the larval migration inhibition assay (LMIA) and the larval exsheathment inhibition assay (LEIA), to evaluate the anthelmintic (AH) properties of tannin-rich plant extracts against Haemonchus contortus infective larvae. The two assays were applied on the same batch of H. contortus infective larvae exposed to water/acetonic extracts obtained from four tropical plants with different tannin contents: Acacia gaumeri, Brosimum alicastrum, Havardia albicans and Leucaena leucocephala. Increasing concentrations (0, 75, 150, 300, 600, 1200 μg/ml PBS) of lyophilized extracts were used in both in vitro assays. A general lineal model test was used to determine the dose-effect in the LMIA or the difference in the percentage of exsheathed larvae between the respective control and treated groups. The LMIA showed a dose-dependent AH effect for H. albicans (P<0.001) and A. gaumeri (P<0.05), but not for L. leucocephala and B. alicastrum. In contrast, the exsheathment process was significantly affected by all doses of H. albicans and A. gaumeri extracts and a significant dose-dependent effect was found for B. alicastrum and L. leucocephala. Calculation of lethal dose (LD) was possible with LEIA using B. alicastrum and L. leucocephala but not with H. albicans and A. gaumeri as the lowest tested concentration was achieving more than 50% inhibition. Calculation of LD with the LMIA results was not feasible. These results suggest that tannin-rich plant extracts are more potent inhibitors of the exsheathment of H. contortus L(3) larvae than their motility. This information underlines the difference of sensitivity between methodological procedures to evaluate the AH properties of plant extracts on the same nematode stage.  相似文献   

Histopathological,Immunohistochemical, Lectinhistochemical and Molecular Findings in Spontaneous Bovine Abortions by Campylobacter fetus     

EL Morrell  CG Barbeito  CA Odeón  EJ Gimeno  CM Campero 《Reproduction in domestic animals》2011,46(2):309-315

  相似文献