口蹄疫病毒抗原保护剂的研究

[目的]研究几种(海藻糖、蔗糖、山梨醇、聚乙烯吡咯烷酮、硫脲、明胶、L-精氨酸、抗坏血酸)保护剂,为口蹄疫抗原保护剂配方的形成提供参考。[方法]用三因素、三水平、双重复正交试验方法筛选出了对口蹄疫病毒(FMDV)抗原保护效果最好的I(4#)保护剂配方,以加保护剂A(已申请专利)的病毒为对照,比较其在不同条件下的TCID50和146s抗原的含量。[结果]通过方差分析4#保护剂保存病毒测得TCID50极显著的高于1、3、5、6、7、8号,显著高于2、9。将4#保护剂加入被保存的病毒抗原中,分别于4℃下保存90、120、150 d,其logTCID50分别为5.3、5.0和4.5,而加保护剂A(已申请专利)的对照病毒则为5.0、4.5和4.3;在37℃下保存40、50和60 h,其logT-CID50分别为4.5、2.5和1.0;而加保护剂A的对照病毒则为3.5、1.5和0.5,为了进一步验证保护剂对FMDV抗原的保护性能,进行了FMDV146s抗原含量的测定。分别于4℃下保存150 d,37℃下保存40 h,测得结果分别为0.796、0.462μg/ml,而加保护剂A的对照病毒则为0.602、0.307μg/ml。[结论]该复合配方保护剂I(4#)对FMDV有效抗原的保护作用优于保护剂A,尤其是病毒保护剂对提高FMDV的冷冻保存时间和耐热效能作用明显。     

A rapid method to monitor fungicide sensitivity in the pecan scab pathogen, Fusicladium effusum

Commercial production of pecans in the southeastern U.S. relies on fungicide applications to control scab, caused by Fusicladium effusum. Under intense disease pressure, 10–15 applications may be made per season and the potential development of fungicide resistance is a major concern. A rapid method was developed to determine sensitivity of the pathogen to protectant chemicals based on conidia germination, and to fungicides active on post-appressorial pathogen stages based on micro-colony growth. This method uses conidia transferred directly from lesions to fungicide-amended media. Using this method, sensitivity profiles were determined for isolates from three non-treated orchards with little or no fungicide use histories and from 33 commercial orchards in 2008 with a history of fungicide use. Compared to the non-treated orchards, significant reductions in in vitro sensitivity were detected in 20 orchards to fentin hydroxide, in 4 orchards to dodine, in 6 orchards to thiophanate-methyl and in 20 orchards to propiconazole. The novel methodology will be useful for monitoring fungicide sensitivity of F. effusum populations and evaluating resistance management programs in commercial pecan orchards.     

氯霉素速测金标试纸条及其保护剂配方研究

 【目的】研制出一种适合于氯霉素残留快速测定的金标试纸条,并对该试纸条的保护剂进行研究,使得研制出的试纸条保存期足够的长。【方法】根据竞争性金免疫层析法原理,研制了氯霉素速测金标试纸条,并选择了蔗糖、葡聚糖、聚乙烯吡咯烷酮（PVP）、聚乙二醇（PEG）、牛血清蛋白（BSA）、表面活性剂Tween20、防腐剂等物质,采用经验尝试法配制了一系列的配方,对试纸条不同部位进行处理,通过37℃和60℃下热稳定性测试,并与未经稳定剂处理的对照进行比较,筛选出适宜的试纸条保护剂。【结果】经该复合保护剂处理的氯霉素速测金标试纸条,在4℃、37℃和60℃下分别保存180 d、30 d和10 d,显色基本不变,对于标准溶液,其检测灵敏度（目测）可达到1.5 ng?ml-1。未经该复合保护剂处理的氯霉素速测金标试纸条,在4℃、37℃和60℃下保存60 d、3 d和1 d后就迅速失活,无法用于检测。【结论】 研制出的氯霉素金标试纸条检测灵敏度较高（对于添加样品,检测灵敏度为0.75～1.5 ng?ml-1）,经保护剂处理后,4℃下至少可保存半年。     

Toxicity and protectant potential of camphor,a major component of essential oil of Ocimum kilimandscharicum,against four stored product beetles

The biological activity of camphor, a major component of essential oil of the basil shrub, Ocimum kilimandscharicum, against the beetles, Sitophilus granarius, S. zeamais, Tribolium castaneum and Prostephanus truncatus, was investigated in the laboratory using contact toxicity, grain treatment and repellency assays. Camphor applied either topically, impregnated on filter papers or whole wheat and maize grains was highly toxic to all the four species. Beetle mortality was dosage-dependent with the highest doses of 100 mg/ filter paper and 100 mug/insect evoking over 93% and 100% mortalities, respectively, in S. granarius, S. zeamais and P. truncatus after 24 h exposure. Similar doses induced 70% and 100% mortality in T. castaneum. Camphor impregnated on the grain surface was more effective than on filter paper. There was, however, highly significant reduction in toxicity in grain after only 24 h following treatment. Development of eggs and immature stages within grain kernels, as well as progeny emergence, was completely inhibited in camphor-treated grain. Camphor was also highly repellent to the beetles with overall repellency in the range of 80 - 100%. The potential use of suitable products derived from O. kilimandscharicum as supplementary or alternative grain protectants against insect damage in traditional grain storage in developing countries is discussed.     

Preservation of <Emphasis Type="Italic">Alfalfa mosaic virus</Emphasis> by freezing and freeze-drying and similarities to Cucumoviruses

Alfalfa mosaic virus (AMV) belongs to the genus Alfamovirus of the family Bromoviridae, for which the virions are stabilized by dominant protein–RNA interactions. The infectivity of purified AMV preparations stored frozen at −20°C decreased to 10–20% in 2 years. In addition, the virion peak profiles after sucrose density gradient centrifugation (SDGC) was reduced to a single, broad peak as a result of virus particle degradation, and the peaks for the extracted virion RNA decreased. However, additives such as 0.5% peptone or 2.5% sucrose were markedly protective such that infectivity and the SDGC profiles of the virus particles and virion RNA remained essentially unchanged after 5–8 years of freezing. Infectivity of the purified AMV decreased to c. 50%, and virus particles deteriorated immediately after freeze-drying. The addition of 1.0–7.5% sucrose suppressed alterations in infectivity, particle morphology and virion RNA after freeze-drying and other preservation processes. The characteristics of AMV preservation were similar to those reported in a previous study on cucumoviruses. Consequently, viruses belonging to the Bromoviridae may preserve well with sucrose in conjunction with freezing or freeze-drying.