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排序方式: 共有237条查询结果,搜索用时 15 毫秒
121.
Munir Iqbal Tahir Yaqub Nadia Mukhtar Muhammad Z Shabbir John W McCauley 《Veterinary research》2013,44(1):100
Genetic changes in avian influenza viruses influence their infectivity, virulence and transmission. Recently we identified a novel genotype of H9N2 viruses in widespread circulation in poultry in Pakistan that contained polymerases (PB2, PB1 and PA) and non-structural (NS) gene segments identical to highly pathogenic H7N3 viruses. Here, we investigated the potential of these viruses to cause disease and assessed the transmission capability of the virus within and between poultry and wild terrestrial avian species. Groups of broilers, layers, jungle fowl, quail, sparrows or crows were infected with a representative strain (A/chicken/UDL-01/08) of this H9N2 virus and then mixed with naïve birds of the same breed or species, or different species to examine transmission. With the exception of crows, all directly inoculated and contact birds showed clinical signs, varying in severity with quail showing the most pronounced clinical signs. Virus shedding was detected in all infected birds, with quail showing the greatest levels of virus secretion, but only very low levels of virus were found in directly infected crow samples. Efficient virus intra-species transmission was observed within each group with the exception of crows in which no evidence of transmission was seen. Interspecies transmission was examined between chickens and sparrows and vice versa and efficient transmission was seen in either direction. These results highlight the ease of spread of this group of H9N2 viruses between domesticated poultry and sparrows and show that sparrows need to be considered as a high risk species for transmitting H9N2 viruses between premises. 相似文献
122.
Arafa NM 《Pakistan journal of biological sciences: PJBS》2010,13(20):966-976
The study aimed to evaluate the effect Echinacea extract (E) on the testicular antioxidants function in normal rats or that subjected to anti-androgenic compound, cyproterone acetate (CA). Rats were divided into 5 groups treated daily via an oral tube for two intervals 2 and 4 weeks, 1st control, 2nd E (Echinacea treated group in dose 63 mg kg(-1)), 3rd CA (cyproterone acetate treated group in dose 25 mg kg(-1)), 4th E+CA and 5th E as prophylactic one week before E+CA treatment with the same aforementioned E or CA doses. The body, testes, epididymis and vas deferens weights were recorded. Sperm count, Nitric Oxide (NO), calcium ion (Ca2+) and malondialdhyde (MDA) contents in addition to superoxide dismutase (SOD), glutathione S-transferase (GST) activities were determined in testicular tissues. CA exhibited direct negative effect on reproductive organs weight and significant reducing effect on sperm count and Ca2+ contents. SOD and GST activities significantly decreased in addition to significant increase in NO, MDA contents reflecting the oxidative status of testis in CA treated rats. The prophylactic effect of E treatment, in time related manner, showed significant improvement in the antioxidant status of the testicular tissue which is more pronounced as compared to E+CA treatment. 相似文献
123.
Nadia Bertazzon Michele Borgo Stefano Vanin Elisa Angelini 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):185-197
The genetic variability among Grapevine leafroll-associated virus 2 (GLRaV-2) isolates was investigated in several grapevine accessions from various geographic origins in three genomic fragments,
which encode the 70 kDa heat-shock protein homologue, the coat protein and the ∼60 kDa protein. The majority of the isolates
were identical or only slightly different from one another and formed a monophyletic group. Several other variants were found
which differed greatly from the main cluster and were mostly present in autochthonous or specific vine cultivars. Phylogenetic
analyses on the CP gene sequences, including the isolates analyzed in this work and some others from related literature, allowed
five clades to be identified (PN, H4, RG, BD and PV20). Biological trials for graft incompatibility and leafroll symptoms
revealed that GLRaV-2 divergent variants had different pathological properties, mainly according to their phylogenetic grouping.
The BD isolate seemed to be a mild variant of the virus, because it was unable to induce graft incompatibility and it rarely
caused leafroll symptoms. The RG isolate appeared to be a more virulent variant, given the strong decrease in rooted grafted
grapevines obtained in nursery, in particular with the use of certain rootstocks; however, it does not induce leafroll symptoms.
The variants belonging to the PN group, which were the most widespread, caused both graft incompatibility and leafroll symptoms,
according to the viral variant. Graft incompatibility also proved to depend strongly on the rootstock used. 相似文献
124.
Guangling Jiao Joseph P. M. Hui Ian W. Burton Marie-Hélène Thibault Claude Pelletier Josée Boudreau Nadia Tchoukanova Balaji Subramanian Yahia Djaoued Stephen Ewart Jacques Gagnon Kathryn Vanya Ewart Junzeng Zhang 《Marine drugs》2015,13(6):3849-3876
Northern shrimp (Pandalus borealis) oil, which is rich in omega-3 fatty acids, was recovered from the cooking water of shrimp processing facilities. The oil contains significant amounts of omega-3 fatty acids in triglyceride form, along with substantial long-chain monounsaturated fatty acids (MUFAs). It also features natural isomeric forms of astaxanthin, a nutritional carotenoid, which gives the oil a brilliant red color. As part of our efforts in developing value added products from waste streams of the seafood processing industry, we present in this paper a comprehensive characterization of the triacylglycerols (TAGs) and astaxanthin esters that predominate in the shrimp oil by using HPLC-HRMS and MS/MS, as well as 13C-NMR. This approach, in combination with FAME analysis, offers direct characterization of fatty acid molecules in their intact forms, including the distribution of regioisomers in TAGs. The information is important for the standardization and quality control, as well as for differentiation of composition features of shrimp oil, which could be sold as an ingredient in health supplements and functional foods. 相似文献
125.
Foliar application of microdoses of sucrose to reduce codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) damage to apple trees
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126.
de Almeida NR Danelli MG da Silva LH Hagiwara MK Mazur C 《Journal of Feline Medicine and Surgery》2012,14(8):583-586
Peripheral blood smears of 1094 domestic cats were collected and tested by indirect immunofluorescence antibody assay for p27 antigen in cells to study the prevalence and risk factors for feline leukemia virus (FeLV) in the state of Rio de Janeiro. Sex, age, breed, outdoor access, neutering status, type of habitation (household, shelter, veterinary clinics and other places), number of household cats and clinical signs were registered on a form. Among the tested samples, 11.52% were positive. Risk factors for FeLV infection included outdoor access, age range between 1 and 5 years old, and cohabitation with numerous cats. 相似文献
127.
128.
Abdolali Hesami Nadia Jafari Malek Hossein Shahriari Mokhtar Zolfi 《Communications in Soil Science and Plant Analysis》2017,48(16):1943-1954
The present study was carried out to investigate the effect of nitrogen (N) and zinc (Zn) fertilization on yield components and composition of Phoenix dactylifera L. cv. Kabkab during two growing seasons. This study was conducted by using factorial experiment in randomized complete block design with four replications. Aqueous solution of Zn was injected to trunk at the rate of 0, 1.15, and 2.30 g L?1. N was applied at 0, 160, 345, and 460 g per palm tree. Sources of N and Zn were urea and zinc sulfate heptahydrate (ZnSO4.7H2O), respectively. Each year N fertilizer was added in two equal applications, one before flowering and one at fruit setting. N was applied at 1.5 m from the palm trunk. The trees were subjected to the usual farm management, for example, artificial pollination (only one source of pollen grains was used to avoid the metaxenic effects), pruning and irrigation. Results indicated that application of N and Zn had significant effects on fruit set, fruit yield, fruit weight, bunch weight, fruit size, N and Zn leaf contents, total soluble solids (TSS), reducing sugar and total sugar. However, more increments in these parameters were obtained with N in combination with Zn. The suitable combination of the nutrients found for date palm tree under the prevailing conditions was the application of 345 g N and 2.30 g L?1 Zn for injection. 相似文献
129.
Nadia Ghezal Asma Rinez Ines Zribi Muhammad Farooq Luigino Troisi Giuseppe Cannazza 《Journal of plant nutrition》2017,40(14):1993-2005
In this study, the influence of aqueous and organic extracts of different plant parts (flowers, leaves, and stems) of Typha angustifolia on the germination and early seedling growth of field pea (Pisum sativum L.) was evaluated. Chemical composition of extracts of different plant parts of Typha was also determined. Aqueous (20, 40, 60, 80, and 100 g L?1) and organic extracts (at 0.5, 1, and 2 mg mL?1) were applied to the seeds of two pea cultivars, Douce de Provence and Lincoln, placed in Petri dishes. Application of extracts had a beneficial effect on germination and early seedling growth of both pea cultivars. However, aqueous extract of leaves showed the most beneficial effect at 60 and 40 g L?1 for the cultivars Douce de Provence and Lincoln, respectively. The effect could be attributed to the allelochemicals present in the aqueous extracts. Petroleum ether and chloroform extracts of leaves had the most stimulating effect on the germination and early seedling growth of pea. Analysis of Typha extracts indicated the presence of vitamin E in leaves, which could be responsible forthis stimulation. Moreover, Typha leaves also had substantial amount of flavonoids. In conclusion, the allelopathic activity of of Typha was dependent on the plant part, the solvent nature, the concentration of the extracts tested, and on the pea cultivar. Application of leaf extract was the most effective in improving the germination rate and early seedling growth of pea. 相似文献
130.
Viktor V. Husak Nadia M. Mosiichuk Olga I. Kubrak Tetiana M. Matviishyn Janet M. Storey Kenneth B. Storey Volodymyr I. Lushchak 《Fish physiology and biochemistry》2018,44(3):841-852
Copper is an essential element, but at high concentrations, it is toxic for living organisms. The present study investigated the responses of goldfish, Carassius auratus, to 96 h exposure to 30, 300, or 700 μg L?1 of copper II chloride (Cu2+). The content of protein carbonyls was higher in kidney (by 158%) after exposure to 700 mg L?1 copper, whereas in gills, liver, and brain, we observed lower content of protein carbonyls after exposure to copper compared with control values. Exposure to copper resulted in increased levels of lipid peroxides in gills (76%) and liver (95–110%) after exposure to 300 and 700 μg L?1 Cu2+. Low molecular mass thiols were depleted by 23–40% in liver and by 29–67% in kidney in response to copper treatment and can be used as biomarkers toxicity of copper. The activities of primary antioxidant enzymes, superoxide dismutase and catalase, were increased in liver as a result of Cu2+ exposure, whereas in kidney catalase activity was decreased. The activities of glutathione-related enzymes, glutathione peroxidase, glutathione-S-transferase, and glutathione reductase were decreased as a result of copper exposure, but glutathione reductase activity increased by 25–40% in liver. Taken together, these data show that exposure of fish to Cu2+ ions results in the development of low/high intensity oxidative stress reflected in enhanced activities of antioxidant and associated enzymes in different goldfish tissues. 相似文献