Evaluation of Trypsin Treatment on the Inactivation of Bovine Herpesvirus Type 1 on In Vitro Produced Pre-implantation Embryos     

M D'Angelo  JA Visintin  LJ Richtzenhain  RF Gonçalves 《Reproduction in domestic animals》2009,44(3):536-539

The aim of this study was to evaluate the efficiency of trypsin treatment on the inactivation of bovine herpesvirus type 1 (BoHV-1) on in vitro produced by fertilization and artificially infected bovine embryos. Bovine embryos on day 7 were exposed with 10 μl of BoHV-1, Los Angeles strain 10^7.5 TCID. These embryos and control embryos were divided in two groups: submitted to the sequential washes or to the trypsin treatment according to the International Embryo Transfer Society (IETS) guidelines. The embryos and the last washing drop of each group were used as inoculum to infect Madin Darby bovine kidney (MDBK) cells and submitted to nested PCR reaction using the primer that encodes the gene conserved region of virus glycoprotein gB. The data have shown that the control embryos and their last washing drop were negative. The exposed embryos that were treated with trypsin have shown positive results on the n-PCR and MDBK culture, and their last washing drop were negative. Our data have demonstrated that the trypsin treatment was not able to eliminate the BHV-1 of the embryos, suggesting an interaction between virus and embryo.  相似文献   

Pulmonary function and metabolic physiology of theropod dinosaurs     

JA Ruben  Dal Sasso C  NR Geist  WJ Hillenius  TD Jones  M Signore 《Science (New York, N.Y.)》1999,283(5401):514-516

Ultraviolet light analysis of a fossil of the theropod dinosaur Scipionyx samniticus revealed that the liver subdivided the visceral cavity into distinct anterior pleuropericardial and posterior abdominal regions. In addition, Scipionyx apparently had diaphragmatic musculature and a dorsally attached posterior colon. These features provide evidence that diaphragm-assisted lung ventilation was present in theropods and that these dinosaurs may have used a pattern of exercise physiology unlike that in any group of living tetrapods.  相似文献   

Climate-Ocean Variability and Ecosystem Response in the Northeast Pacific   总被引：1，自引：0，他引：1  

JA McGowan  DR Cayan  LM Dorman 《Science (New York, N.Y.)》1998,281(5374):210-216

The role of climatic variation in regulating marine populations and communities is not well understood. To improve our knowledge, the sign, amplitude, and frequency of climatic and biotic variations should be compared as a necessary first step. It is shown that there have been large interannual and interdecadal sea-surface temperature changes off the West Coast of North America during the past 80 years. Interannual anomalies appear and disappear rather suddenly and synchronously along the entire coastline. The frequency of warm events has increased since 1977. Although extensive, serial, biological observations are often incomplete, it is clear that climate-ocean variations have disturbed and changed our coastal ecosystems.  相似文献   

Evidence for extreme climatic warmth from late cretaceous arctic vertebrates   总被引：1，自引：0，他引：1  

JA Tarduno  DB Brinkman  PR Renne  RD Cottrell  H Scher  P Castillo 《Science (New York, N.Y.)》1998,282(5397):2241-2244

A Late Cretaceous (92 to 86 million years ago) vertebrate assemblage from the high Canadian Arctic (Axel Heiberg Island) implies that polar climates were warm (mean annual temperature exceeding 14 degreesC) rather than near freezing. The assemblage includes large (2.4 meters long) champsosaurs, which are extinct crocodilelike reptiles. Magmatism at six large igneous provinces at this time suggests that volcanic carbon dioxide emissions helped cause the global warmth.  相似文献   

Killer whale predation on sea otters linking oceanic and nearshore ecosystems   总被引：2，自引：0，他引：2  

JA Estes  MT Tinker  TM Williams  DF Doak 《Science (New York, N.Y.)》1998,282(5388):473-476

After nearly a century of recovery from overhunting, sea otter populations are in abrupt decline over large areas of western Alaska. Increased killer whale predation is the likely cause of these declines. Elevated sea urchin density and the consequent deforestation of kelp beds in the nearshore community demonstrate that the otter's keystone role has been reduced or eliminated. This chain of interactions was probably initiated by anthropogenic changes in the offshore oceanic ecosystem.  相似文献   

Protactinium-231 and thorium-230 abundances and high scavenging rates in the western arctic ocean     

HN Edmonds  SB Moran  JA Hoff  JN Smith  RL Edwards 《Science (New York, N.Y.)》1998,280(5362):405-407

The Canadian Basin of the Arctic Ocean, largely ice covered and isolated from deep contact with the more dynamic Eurasian Basin by the Lomonosov Ridge, has historically been considered an area of low productivity and particle flux and sluggish circulation. High-sensitivity mass-spectrometric measurements of the naturally occurring radionuclides protactinium-231 and thorium-230 in the deep Canada Basin and on the adjacent shelf indicate high particle fluxes and scavenging rates in this region. The thorium-232 data suggest that offshore advection of particulate material from the shelves contributes to scavenging of reactive materials in areas of permanent ice cover.  相似文献