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排序方式: 共有405条查询结果,搜索用时 31 毫秒
51.
在紫薇上,有3种白粉菌寄生——Uncinulliella australiana,Erysiphe lagerstroemiae和Phyllactinia corylea经研究,在昆明地区紫薇上的白粉菌应为Uncinulliella australiana,这与雅安地区所发生的紫薇白粉菌同属一种。菌丝体在紫薇芽鳞下越冬,春天来临或给予合适的条件,菌丝体便开始发育蔓延,对紫薇造成初侵染。分生孢子的散布受降水、温度相对湿度及风速的影响。降水明显对分生孢子散布不利。分生孢子散布具有明显的昼夜变化节律。在一年中,紫薇白粉病在春季开始发生,雨季(6月到9月)达到高峰,在晚秋停止了发展。 相似文献
52.
卵孢白僵菌感染草地蛴螬的研究 总被引:3,自引:0,他引:3
从湖南南山牧场草地上自然罹病的蛴螬虫体上分离出一株卵孢白僵菌。在室内和野外人工草地进行蛴螬活虫感染试验,结果表明,在室内用卵孢白僵菌孢子液感染蛴螬活虫,30天内蛴螬感染率达64.6─92.1%;野外草地试验,用卵孢白僵菌制成菌剂拌少量细土撤于地表,20天内,蛴螬感染率为70%以上。 相似文献
53.
Fusarium oxysporum对苗期大豆具有较强的致病作用。病原菌自伤口或直接侵入大豆幼苗根部的皮层组织,随着病原菌的侵入和扩展,细胞出现坏死,组织发生崩解,根部组织表现红褐色病斑。环境因素对病原菌的侵染时期和在大豆体内潜育时间的长短有着明显的影响。侵染时期主要受病原菌侵入前自身所处状态和寄主的影响,侵入后潜育时间的长短则受植株状态的影响。土壤环境条件直接影响着病原菌的侵入和寄主的抗病性,间接影响着病原菌在大豆植株体内的扩展和病症的表现。 相似文献
54.
青海牦牛和藏羊泡球蚴的感染及病理形态学观察 总被引:2,自引:0,他引:2
对青海高原地区牦牛和藏羊体内多房棘球蚴的感染进行调查,感染率分别为4.7%和5.4%;用病理组织学技术对牦牛和藏羊体内寄生的泡球蚴形态结构进行观察,证实大部分泡球蚴结构受损或退化,虽然部分结构高度分化,但不产生或极少产生原头蚴,并对其流行病学意义进行了讨论。 相似文献
55.
Martins ML Vieira FN Jerônimo GT Mouriño JL Dotta G Speck GM Bezerra AJ Pedrotti FS Buglione-Neto CC Pereira G 《Fish physiology and biochemistry》2009,35(1):219-222
This study evaluated the total and differential leukocyte counting and the phagocytic activity in Nile tilapia Oreochromis niloticus experimentally injected with Enterococcus sp. in the swim bladder. Fish were distributed in four treatments in triplicates of non-injected fish, fish injected with
1 ml of sterile saline solution 0.65%, and fish injected with 1 × 103 and 1 × 106 colony-forming units (CFU) of Enterococcus diluted in 1 ml sterile saline. Twenty-four hours after injection, the fish were anesthetized and the blood collected for
white blood cell (WBC) counts, differential counting of WBC, and phagocytic activity of blood leukocytes. The increased numbers
of WBC and lymphocytes were followed by decreased number of monocyte after infection. The percentages of phagocytic activities
in the blood were 55.3 and 55.9%, respectively, in tilapia injected with 1 × 103 and 1 × 106 CFU/ml. 相似文献
56.
弓形虫可感染多种动物引起严重的弓形虫病,为了对不同宿主感染的弓形虫株基因型差异及不同基因型弓形虫虫株的致病力差异进行进一步研究,弓形虫基因型的分析多采用限制性片段长度多态性PCR(PCR-RFLP)、随机扩增多态性DNA、多位点PCR-RFLP分析、DNA序列分析和微卫星DNA序列分析等技术,扩增位点多选择SAG1、SAG2、SAG3、BTUB和GRA6等遗传标记。传统的弓形虫基因型主要有3个,随着基因型研究的不断深入,越来越多的基因型被发现。本文就弓形虫基因分型研究进展进行讨论分析。 相似文献
57.
Fran?oise P Sanches Thaise Y Tomokane Vania LR Da Matta Mary Marcondes Carlos EP Corbett Márcia D Laurenti 《Acta veterinaria Scandinavica》2014,56(1)
Background
There are only a few studies reporting the role of nitric oxide metabolites for controlling macrophage intracellular parasitism, and these are controversial. Therefore, the present study aimed to evaluate the expression of inducible nitric oxide synthase (iNOS) in the lymph nodes and spleen of dogs affected by visceral leishmaniasis through immunohistochemistry and to determine its correlation with tissue parasite burden and serum interferon (IFN)-γ levels. Twenty-eight dogs were selected and assigned to one of two groups, symptomatic (n = 18) and asymptomatic (n = 10), according to clinical status and laboratory evaluation. A negative control group (n = 6) from a non-endemic region for visceral leishmaniasis was included as well.Results
Parasite density (amastigotes/mm2) was similar between clinical groups in the lymph nodes (P = 0.2401) and spleen (P = 0.8869). The density of iNOS+ cells was higher in infected dogs compared to controls (P < 0.05), without a significant difference in lymph node (P = 0.3257) and spleen (P = 0.5940) densities between symptomatic and asymptomatic dogs. A positive correlation was found between the number of iNOS+ cells in lymph nodes and interferon-γ levels (r = 0.3776; P = 0.0303), and there was a negative correlation between parasites and iNOS+ cell densities both in lymph nodes (r = −0.5341; P = 0.0034) and spleen (r = −0.4669; P = 0.0329).Conclusion
The negative correlation observed between tissue parasitism and the expression of iNOS may be a reflection of NO acting on the control of parasites. 相似文献58.
In Latin and Central America and in most Asian countries, brucellosis remains an insufficiently studied disease. This study aims to determine the national and regional incidence of brucellosis among cattle (cows) and small ruminants (sheep, goats) in the Republic of Kazakhstan, as well as to identify the effect of climatic and geographical factors on the incidence rates. Thematic maps were created in an open geographic information system QGIS version 2.8. in order to identify the natural and socio-economic factors that influence the spread of the disease overlay method was used. Local cluster analysis was used in order to identify additional causes of the disease. Findings show the following values of Pearson correlation between the overall population and the number of animals infected: 0.68 for cows, p ≤ 0.005, and 0.56 for sheep and goats, p ≤ 0.03. Thus, the larger the heard in a given area, the greater likelihood of having brucellosis. Data processing reveals that Kazakhstan has almost twice as many regions good for cattle breeding as regions that are good for the small ruminants farming. The correlation variables for cattle and small ruminants are approximately the same. On the basis of the performed research the author proposes to amend the accepted methodology of epidemiology surveillance by the methods based on spatial (geographical) analysis. It is also proposed to adjust the process of breeding cattle and small ruminants considering the additional health recommendations that take into account the geographical aspects of the spread of the disease. 相似文献
59.
枣尺蠖核多角体病毒对6种幼虫感染试验 总被引:1,自引:0,他引:1
用枣尺蠖核多角体病毒 (CzNPN)天津毒株病毒悬液 ,采用浸叶法 ,浓度为 2 5× 1 0 7PIB/ml,分别感染饲喂枣尺蠖 (ChihuozaoYang)、槐尺蛾 (SemiothisacinerariaBremeretGrey)、柳毒蛾 (LeucomasalicisLinnaeus)、舞毒蛾[Lymantriadispar (Linnaeus) ]、折带黄毒蛾 [(Euproctisflava (Bremer) ]、榆叶蜂 (ArgecaptivaSmith) 6种 3~ 4龄的幼虫 ,仅枣尺蠖 1种幼虫感病死亡 ,而其它 5种幼虫未见到感病症状 ,说明CzNPV对原始寄主枣尺蠖有较强专一性 ,可作为枣尺蠖生物防治的一个重要措施 相似文献
60.