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221.
Avian reoviruses are transmitted vertically via the egg and horizontally following the ingestion of infected faecal material. Experiments conducted on eight one-day-old specific pathogen free chicks provide evidence for occasional infection through broken skin and localisation in the hock joint. 相似文献
222.
Subcellular distribution of copper in the liver of fetal deer in the last month of gestation 总被引:2,自引:0,他引:2
M J Leighton T J Peters R Hill G D Smith W Holt D M Jones 《Research in veterinary science》1990,49(3):298-305
Fetal deer, in the last month of gestation, accumulate high concentrations of copper in the liver. Livers from fetal deer in late gestation were homogenised and fractionated by continuous sucrose density gradient centrifugation. The distribution of copper closely followed that of DNA; approximately two thirds of the metal was localised to the nuclear fractions with the remaining third in the cytosolic fractions. The fractionation procedure was repeated with digitonin, a lysosomal perturbant: lysosomes were disrupted and the marker enzyme, N-acetyl-beta-glucosaminidase, shifted from the particulate fractions to the cytosolic fractions; the distribution of copper was unaffected. Differential centrifugation of homogenate confirmed that approximately two thirds of the copper was associated with the nuclear fraction. Further confirmation of a nuclear localisation of copper was provided by X-ray microanalysis of purified nuclei. 相似文献
223.
Only two of 49 cats undergoing surgical ligation of congenital extra- and intrahepatic portosystemic shunts died perioperatively, a mortality rate comparable with the mortality rates of dogs undergoing surgical attenuation of congenital portosystemic shunts and cats in which the shunts are attenuated with an ameroid ring constrictor. Thirty (83 per cent) of the 36 cats for which long-term information was available were still alive at a median follow-up period of 47 months (range six to 105 months); the outcome was excellent (no clinical signs) in 20 of them (median follow-up 37 months, range six to 105 months) and good (minimal clinical signs) in seven (median follow-up 39 months, range 10 to 73 months) and none of these 27 cats was on any long-term medication or special diet. The only major cause of morbidity was the development of neurological signs in 18 (37 per cent) of the cats. These included seizures and a wide variety of other neurological signs, and their development and persistence was not affected by the presence of preoperative seizures, the type of shunt, the degree of shunt attenuation or the age of the cat. The serum concentrations of ammonia and preprandial bile acids were normal or significantly below normal in the cats with neurological signs. Liver histopathology was similar in the cats with and without neurological signs. Ten (56 per cent) of the 18 cats that developed neurological signs recovered normal neurological function long term. 相似文献
224.
Eckert RE Neuder LE Bell JL Trujillo JC Jones SL 《Veterinary immunology and immunopathology》2007,118(3-4):294-303
The goal of this study was to define the role for p38 mitogen-activated kinase (MAPK) in the signaling mechanism regulating pro-inflammatory cyclooxygenase (COX) gene expression in lipopolysaccharide (LPS)-activated equine leukocytes for the purposes of identifying novel targets for anti-inflammatory therapy in endotoxemic horses. The p38 MAPK has been shown to positively regulate inflammatory gene expression in human leukocytes and can be activated by a variety of stimuli including LPS, TNF-alpha, and IL-1. Activation-associated phosphorylated p38 MAPK has been implicated in the up-regulation of several inflammatory genes, including COX-2 which ultimately results in the production of prostanoids that are responsible for the pathophysiology associated with endotoxemia. Our hypothesis is that activation of p38 MAPK is essential for LPS-induced COX-2 expression in equine peripheral blood leukocytes. We tested our hypothesis by investigating the effects of the specific p38 MAPK inhibitors SB203580 and SB202190 on LPS-induced COX-2 protein expression and PGE(2) production in equine leukocytes. LPS stimulation activated p38 MAPK and increased COX-2 expression in a dose-dependent manner with maximal activation observed after 30min and 4h, respectively, at a concentration of 10 ng/ml LPS. In contrast, LPS stimulation did not affect COX-1 protein expression. Pretreatment with SB203580 or SB202190 significantly inhibited LPS-induced activation-associated p38 MAPK phosphorylation, COX-2 mRNA and protein levels, and PGE(2) production in equine leukocytes. Maximal inhibition of LPS-induced COX-2 protein expression was achieved at a concentration of 10 microM SB203580. We concluded that p38 MAPK is essential for LPS-induced COX-2 expression suggesting that p38 MAPK is a potential target for anti-inflammatory therapy during equine endotoxemia. 相似文献
225.
226.
Summary A polymorphic microsatellite locus has been located closely linked to the Waxy gene of rice. Primers were designed to allow detection of the microsatellite by utilising the polymerase chain reaction. In screen of 13 commercial rice varieties, four different alleles were found, demonstrating the potential of this marker in commercial rice breeding for starch quality.Abbreviations RFLP
Restriction Fragment Length Polymorphism
- PCR
Polymerase Chain Reaxtion 相似文献
227.
The use of bulked leaf samples from individual plants for amplified fragment length polymorphism (AFLP) analysis was evaluated
as a tool for assessment of genetic diversity in white clover (Trifolium repens L.). Bulking of leaf samples produced slightly simpler AFLP profiles compared to the combined profiles of individual plants
from the same cultivar. Approximately 90% of bands which were present in individual plants were present in bulked samples
of the same cultivar. The majority of those absent were rare bands, shared by less than 25% of individual plants. Replicate
bulk samples gave almost identical banding patterns, demonstrating the robustness of the bulked AFLP technique. Cluster analysis
of AFLP data derived from individual plants resulted in a phenogram similar to that produced from data derived from bulked
samples of the same plants. AFLP analysis of bulked samples detected significant amounts of genetic variability among 52 cultivars
and accessions with genetic similarity values ranging from 0.42 to 0.92. However, cluster analysis of AFLP data only partially
reflected the geographic origin of cultivars and accessions and was not congruent with cluster analysis based on variation
for morphophysiological characters. Bulked AFLP analysis provides a powerful tool for rapid assessment of genetic variability
in white clover and may also be used for cultivar identification.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
228.
Abscisic acid, gibberellin and cell viability in cereal aleurone 总被引:3,自引:0,他引:3
Paul C. Bethke Angelika Fath Yoav N. Spiegel Yong-sic Hwang Russell L. Jones 《Euphytica》2002,126(1):3-11
The aleurone layer of cereals is a secretory tissue whose activity is regulated by abscisic acid (ABA) and gibberellins (GAs).
Whereas GA triggers enzyme synthesis and secretion and initiates a program that culminates in cell death, ABA prevents enzyme
production and cell death. Reactive oxygen species (ROS) are key players in regulating cell viability and GA sensitizes the
aleurone cell to ROS. Sensitivity of GA-treated cells results in part from a reduction in steady-state amounts of mRNAs encoding
enzymes that scavenge ROS. mRNAs encoding catalase, superoxide dismutase and ascorbate peroxidase are almost undetectable
in aleurone layers 24 h after incubation in GA. For layers incubated in ABA, however, the amounts of these mRNAs increase.
Western blotting and enzyme activity assays confirm that GA but not ABA reduced the amount and activity of ROS scavenging
enzymes (Fath et al., 2001b). Substantial amounts of ROS are produced by enzymes engaged in lipid metabolism, and by the electron
transport chain in the mitochondria. Aleurone layers contain abundant stores of triglycerides and ROS are produced as these
lipids are rapidly converted to sugars. We hypothesize that the ROS produced in GA-treated aleurone cells bring about cell
death by disrupting the plasma membrane. Aleurone cells incubated in ABA, on the other hand, are better able to maintain redox
balance. ABA does not initiate rapid triglyceride metabolism, and the activities of ROS-scavenging enzymes remain high in
ABA-treated cells. We conclude that GA initiates a metabolic cascade in aleurone cells that results in death from ROS. ABA
maintains viability by keeping ROS under control.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
229.
Summary The sensitivity of Fragaria seedlings to colchicine is dependent on the plant organ that is treated. Complete immersion of seedlings in a 1.5% colchicine solution results in total lethality, whereas the survival rates were more than 75% even at concentrations of 3.0% when only shoot apices were treated. High proportions of polyploids were isolated by treating shoot apices of seedlings with a 2.0% colchicine solution for 24–28 h. The dropper method is preferred to the tube method as it involves a minimum of manipulation and requires simple equipment. A differential response to colchicine was observed within and between different diploid species, diploid and tetraploid hybrids. 相似文献
230.