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41.
REASONS FOR PERFORMING STUDY: Surveillance of equine influenza viruses has suggested that strains included in currently licensed vaccines are a poor match for those predominantly circulating in the field. OBJECTIVE: To assess the ability of Duvaxyn IE-T Plus to provide cross protection against the newly evolved South Africa/4/03 (H3N8) strain of equine influenza virus. METHODS: The vaccine efficacy was evaluated by challenge infection with influenza strain A/eq/South Africa/4/03 (H3N8) 2 weeks after a primary course of 2 vaccinations with Duvaxyn IE-T Plus given at a 4-week interval. The outcome of challenge in vaccinated ponies was compared with that in unvaccinated animals. RESULTS: At the time of challenge, all vaccinated ponies had high levels of antibody to Newmarket/1/93, Newmarket/2/93 and South Africa/4/03 strains measured by single radial haemolysis. After challenge infection, there were statistically significantly decreased clinical scores and virus shedding was significantly lower in the vaccinated ponies compared to unvaccinated controls. CONCLUSION: Two doses of Duvaxyn IE-T Plus provides good clinical and virological protection against challenge with a variant virus 2 weeks after the 2 doses of vaccine. POTENTIAL RELEVANCE: When variant strains of equine influenza virus first emerge, booster immunisations with currently available vaccines may limit infection provided sufficiently high antibody levels are achieved, suggesting that vaccination in the face of an outbreak may be beneficial.  相似文献   
42.
Mucinous cholangiocarcinoma was diagnosed in a 14-year-old, castrated male, domestic shorthaired cat with marked peritoneal effusion. Cytological confirmation of malignancy by fluid analysis and fine-needle, ultrasound-guided aspiration of the liver was followed by histological examination of tissue samples obtained at surgery and necropsy. No observed response followed chemotherapy with doxorubicin and carboplatin. Electron microscopy and immunohistochemistry helped to further characterize this unusual tumor.  相似文献   
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Background

Invasive Australian populations of redlegged earth mite, Halotydeus destructor (Tucker), are evolving increasing organophosphate resistance. In addition to the canonical ace gene, the target gene of organophosphates, the H. destructor genome contains many radiated ace-like genes that vary in copy number and amino acid sequence. In this work, we characterise copy number and target-site mutation variation at the canonical ace and ace-like genes and test for potential associations with organophosphate insensitivity. This was achieved through comparisons of whole-genome pool-seq data from alive and dead mites following organophosphate exposure.

Results

A combination of increased copy number and target-site mutations at the canonical ace was associated with organophosphate insensitivity in H. destructor. Resistant populations were segregating for G119S, A201S, F331Y at the canonical ace. A subset of populations also had copy numbers of canonical ace > 2, which potentially helps overexpress proteins carrying these target-site mutations. Haplotypes possessing different copy numbers and target-site mutations of the canonical ace gene may be under selection across H. destructor populations. We also detected some evidence that increases in copy number of radiated ace-like genes are associated with organophosphate insensitivity, which might suggest potential roles in sequestration or breakdown of organophosphates.

Conclusion

Different combinations of target-site mutations and (or) copy number variation in the canonical ace and ace-like genes may provide non-convergent ways for H. destructor to respond to organophosphate selection. However, these changes may only play a partial role in organophosphate insensitivity, which appears to have a polygenic architecture. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   
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In the High Plains, corn (Zea mays L.) is an important commodity for livestock feed. However, limited water resources and drought conditions continue to hinder corn production. Drought-tolerant (DT) corn hybrids could help maintain high yields under water-limited conditions, though consistent response of such hybrids is unverified. In this two-year study, the effects of three irrigation treatments were investigated for a DT and conventional maize hybrid, Pioneer AQUAMax P0876HR and Pioneer 33Y75, respectively. In 2013, the drier of the 2 years, irrigation amounts and crop water use (ETc) were greater for the conventional hybrid, but grain water use efficiency (WUE) and harvest index were significantly greater for the DT hybrid. In 2014, grain yields and WUE were not significantly different between hybrids. However, irrigation amounts, ETc and biomass yields were greater for the conventional hybrid. Results from both years indicate that the DT hybrid required less water to maximize grain yield as compared to the conventional hybrid. Producing relatively high yields with reduced amounts of water may provide a means for producers to continue corn production in a semiarid environment with declining water supplies.  相似文献   
47.
The commercial, welfare and environmental impacts of rearing small colonies of free-range chickens in newly planted woodland at two sites in the UK, during the first 2 years of the enterprise, were investigated. Newly planted rather than established trees were used so that commercially viable species could be planted in a way that would suit the management of the chicken enterprise, and small colonies were used so that farmers wishing to diversify could buy into the system progressively. It was anticipated that marketing a high specification product would provide an immediate income, whilst waiting for the future investment in trees to grow.  相似文献   
48.
Although there has been increasing research on the adoption of agroforestry technologies over the last decade, few such studies have assessed uptake over a long period and many are based on a single snapshot in time. Furthermore, most of these studies have mainly looked at non-adopters and adopters: only recently have social scientists considered testers. A further category of users neglected in adoption studies has been re-adopters of technologies. Studying this group provides an interesting and more nuanced understanding of adoption and re-adoption. Methodologically, most adoption studies use quantitative methods and fail to link their findings to wider socio-economic, political and institutional settings. This paper presents a study of the dynamics of improved tree fallow use by farmers in Siaya and Vihiga districts of western Kenya over a period of eight years. It uses both qualitative and quantitative data to critically discuss the motivations of adopters, testers/rejecters and re-adopters. The results show that the process of adoption is highly dynamic and variable with farmers planting improved fallows and discontinuing or re-adopting them due to a whole range of factors, of which soil fertility improvement is just one. These factors included incentives from projects, the tying of adoption to credit programmes, prestige, participation in seminars/tours and the availability of a seed market from projects promoting improved fallows. Farmers planting improved fallows for such reasons may be termed ‘pseudo-adopters’. There were significant differences in adoption between the two districts, with more farmers in Siaya planting improved fallows than in Vihiga. A majority of farmers in Vihiga (53%) who were given seed never planted improved fallows, even though they had been exposed to the technology. Some 40% of farmers in Siaya and 38% in Vihiga planted improved fallows but later rejected them. This has some important implications for research and development. For improved fallow technologies to be attractive to farmers, they must provide other tangible economic benefits besides soil fertility improvement. This presents a challenge to researchers who must better attune themselves to the needs and demands of farmers if they wish to see their research findings widely adopted.  相似文献   
49.
The marine microorganisms thraustochytrids have been explored for their potential in the production of various bioactive compounds, such as DHA, carotenoids, and squalene. Squalene is a secondary metabolite of the triterpenoid class and is known for its importance in various industrial applications. The bioinformatic analysis for squalene synthase (SQS) gene (the first key enzyme in the tri-terpenoid synthesis pathway), that is prevailing among thraustochytrids, is poorly investigated. In-silico studies combining sequence alignments and bioinformatic tools helped in the preliminary characterization of squalene synthases found in Aurantiochytrium limacinum. The sequence contained highly conserved regions for SQS found among different species indicated the enzyme had all the regions for its functionality. The signal peptide sequence and transmembrane regions were absent, indicating an important aspect of the subcellular localization. Secondary and 3-D models generated using appropriate templates demonstrated the similarities with SQS of the other species. The 3-D model also provided important insights into possible active, binding, phosphorylation, and glycosylation sites.  相似文献   
50.
过去人们常认为,由于刚出壳雏鸡的免疫系统尚未发育成熟,同时肠道内缺乏有益的微生物,因而处于高度的敏感期,此时接种沙门氏菌苗产生的保护作用很有限。然而,最新的研究表明,在这些敏感期接种疫苗,可诱发产生保护作用。  相似文献   
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