两株新分离的APMV-I毒株感染SPF鸡的超微病理变化     

袁莉民  王永坤  朱国强  郁斌 《畜牧兽医学报》2004,35(5):565-569

将APMV-I鹅源分离株YG97鸡源分离株Y98和NDV强毒株F48E8感染SPF鸡，运用透射电镜观察该2株病毒分离株对机体细胞的影响，结果显示3株禽副黏病毒均引起机体肝、胰、脾、肾、心、胃、十二指肠和直肠等实质器官组织细胞的超微病变，如黏膜上皮细胞多处受损，表面微绒毛脱落；实质细胞核固缩、凝聚、凹陷、核多形性，线粒体嵴断裂、空泡样变、膜溶解，粗面内质网扩张、囊泡变，细胞浆的囊泡内及细胞浆内存在有囊膜的成熟病毒粒子等，但YG97和Y98对不同实质器官的组织细胞超微病变程度不一：胃、肝、胰、脾、肾超微病变比心脏的超微病变严重。电镜观察结果还表明：3株禽副黏病毒引起宿主细胞的超微病变有2种形式：坏死性病变和凋亡性病变。  相似文献   

感染白粉病小麦叶片细胞的超微变化   总被引：2，自引：0，他引：2  

兰景华 《西南大学学报(自然科学版)》1992,14(4):289-291

小麦感染白粉病菌后,叶片叶绿体肿胀,双层膜不完整或消失,基粒片层排列疏松紊乱,细胞中出现许多由单层膜围成的大小不等的空胞和类似纤维状的膜状物,细胞核膜消失,质壁分离.  相似文献   

西藏沙化动态及其原区   总被引：1，自引：0，他引：1  

徐志高李凤武  孙继霖 《中南林业调查规划》2006,25(3):15-18

西藏自治区是我国沙化最严重的地区之一。2004年调查结果表明，西藏沙化面积为216842．7km^2其中重度以上的沙化面积占总沙化面积的91．53％；沙化类型以戈壁占绝对优势：草地、未利用地是主要的沙化土地利用类型。全区沙化总体上呈恶化趋势，沙化土地面积增加，沙化程度加剧，但拉萨、山南等地沙化土地有所减少。西藏土地沙化变化是受自然因素与人为因素共同作用的结果。  相似文献   

Rural depopulation and recent landscape changes in a Mediterranean region: Consequences to the breeding avifauna   总被引：8，自引：0，他引：8  

Eric Preiss  Jean-Louis Martin  Max Debussche 《Landscape Ecology》1997,12(1):51-61

We studied the vegetational and avifaunistic changes following rural depopulation in an area covering 2,600 ha north of Montpellier (Southern France). The study area is covered by a mosaic of Mediterranean habitats that includes cultivation, grasslands, shrublands, and woodlands and is representative of the natural features present and of the human usage practiced so far in this part of the Mediterranean. We sampled the vegetation and the bird fauna in the same 193 census plots in 1978 and in 1992. At both the habitat and landscape scales the cover of woody plants increased significantly. Open habitats tend to disappear. As a consequence the abundance of open-habitat bird species decreased significantly whereas the abundance of forest birds increased significantly. These changes favor a pool of forest species widespread in western Europe and reduce habitat availability for open habitat and shrubland species. Many of the latter are Mediterranean species whose distribution in Western Europe could become reduced under current landscape dynamics. Our observation of more woodlands and their typical birds and of less open habitats and their associated avifauna is not consistent with the traditional worry shown by the public and the managers about the regression of forests and woodlands in the Northern Mediterranean as a consequence of fire.  相似文献   

离体条件下水稻种衣剂对串珠镰刀菌生长及形态毒理影响     

刘西莉  张龙  李健强  房双龙 《植物病理学报》2002,32(4):332-337

 检测了黑龙江水稻主产区4个当地主栽品种的种子内部镰刀菌寄藏情况,测定了20%克福甲和20%克多甲种衣剂对种子带菌消毒处理效果及对水稻串珠镰刀菌(Fusarium moniliforme)的抑菌作用和联合毒力,并借助扫描电镜观察了上述2种混配种衣剂对串珠镰刀菌的形态毒理影响。结果表明,种子内部镰刀菌的分离频率高达56.7%~96.0%,其中串珠镰刀菌的分离频率为32.6%~48.2%,2种种衣剂对带菌种子具有显著的消毒处理效果。20%克福甲和20%克多甲种衣剂对镰刀菌F.moniliforme的毒力指数分别为457.11和802.04,增效倍数分别为6.53和0.13。20%克多甲种衣剂(多菌灵:甲基立枯磷为5:5,W/W)对串珠镰刀菌的抑菌作用优于20%克福甲种衣剂(福美双:甲基立枯磷为8:6,W/W),增效作用低于20%克福甲种衣剂。电镜观察表明,种衣剂低浓度至高浓度处理下均可引起串珠镰刀菌菌丝不同程度的异常生长,表现为主菌丝局部膨大或形成菌丝束,菌丝顶端异常膨大、缢缩或形成穗状和花絮状分枝。  相似文献   

内毒素介导动物急性肾功能衰竭机理的试验研究   总被引：2，自引：0，他引：2  

吴立夫  周建国 《畜牧兽医学报》2005,36(3):283-287

为了阐明内毒素介导急性肾功能衰竭的机理,观察了内毒素性肾功能衰竭家兔血液凝固性变化和肾脏的病理形态学变化。与对照组家兔比较,模型组家兔血小板计数和血浆纤维蛋白原含量极显著降低(P<0 01),出血时间、凝血时间、凝血酶原时间和白陶土部分凝血活酶生成时间显著或极显著延长(P<0 05,P<0 01)。另一方面,内毒素注射在全部模型组家兔导致了弥漫性血管内凝血,71.4%的肾小球中发现了微血栓,肾小球纤维素密度指数达60 6%。此外,96.2%的肾小管上皮细胞变性坏死,84.1%的肾小管中有管型形成。对照组家兔均未发现这些病理变化。上述试验结果揭示,内毒素引发了弥漫性血管内凝血,而肾小球毛细血管内广泛形成的微血栓阻断了肾小球毛细血管血流,从而导致肾小球滤过率降低,这是内毒素介导急性肾功能衰竭的首要机理。此外,肾小管上皮细胞的变性、坏死可损害其重吸收和分泌功能,管型形成可阻塞肾小管管腔并增大肾球囊内的压力,这些也都是在内毒素介导急性肾功能衰竭发生发展过程中起重要作用的因素。  相似文献   

芦苇和白刺空间格局对青土湖生态输水的响应     

陈政融  刘世增  刘淑娟  孙涛 《草业科学》2015,(12):1960-1968

石羊河尾闾湖——青土湖位于腾格里沙漠和巴丹吉林沙漠边缘,是阻隔两大沙漠合围的生态屏障。自2010年开始连续5年向青土湖进行生态输水并形成一定规模的水面,对促进区域植被恢复和保护民勤湖区绿洲具有重要的生态意义。本研究选用2008年、2010年、2011年、2012年、2013年、2014年的高分辨率遥感影像资料同时结合研究区的实地调查资料,对形成人工水面的面积和输水前后的芦苇(Phragmites australis)、白刺(Nitraria tangutorum)群落面积进行了统计分析和对比。结果表明,5年连续输水形成叠加效应,水面面积成倍增加,芦苇相对频度逐年增加和白刺相对频度逐年减少,芦苇群落(Form.P.australis)面积增加了8.43倍,临接水域和水域中的白刺群落(Form.N.tangutorum)消失,白刺面积减少了68.00%。人工输水促进了芦苇群落依水蔓延,镶嵌于水域成片分布;距水面50 m范围的白刺群落由连续成片成点状。输水促进了湿生植物生长,导致荒漠植物种退化。  相似文献   

王家沟小流域50a土地利用动态变化分析   总被引：2，自引：1，他引：1  

张勇  蔡继清  孙雁君  杜轶 《山西农业科学》2011,39(8):897-899

以经过50多a水土保持综合治理的王家沟小流域为研究对象,利用其1959—2008年土地利用数据,对该流域土地利用动态变化进行分析。结果表明,调整土地利用结构是王家沟小流域水土保持综合治理的一项关键性措施。  相似文献   

Effects of burning on soil macrofauna in a savanna-woodland under different experimental fuel load treatments     

《Applied soil ecology》2014

In West African savanna-woodland, the use of prescribed burning as a management tool has ecological implications for the soil biota. Yet, the effects of fire on soil inhabiting organisms are poorly understood. The aim of this study was to examine the responses of soil macro-invertebrates to early fires in a Sudanian savanna-woodland on a set of experimental plots subject to different fuel load treatments. The abundance of major macro-invertebrate taxa and functional groups, and taxon richness were quantified in soil cores collected from three different soil layers before and immediately after burning. The results indicated that, overall, there was substantial spatial and temporal variation in the composition of macro-invertebrate assemblages. The immediate effects of fire were to reduce total invertebrate numbers and numbers of many invertebrate groups dramatically. This is probably due to the fact that many of the surface-dwelling macrofauna perished as a result of less favorable microclimate due to fire, diminished resources, or migrate to safer environments. Fuel load treatment did not affect the community taxonomic richness or abundance of the soil-dwelling fauna. Furthermore, annual changes in community composition were more pronounced at the burnt site than in the control. This could be related to the inter-annual difference in precipitation pattern recorded during the two-year study period at our site. Since soil macrofauna population declines in fire-disturbed areas, increasing fire prevalence may jeopardize the long-term conservation of fire sensitive macrofauna groups. Special fire management attention is therefore recommended with due consideration to the type of burning and fuel properties to avoid the detrimental effects of intense fire affecting the resilience of savanna soil macrofauna species.  相似文献   

一起山羊地方性鼻内肿瘤的诊断     

王景  周曼  何亚鹏  付明哲  许信刚 《动物医学进展》2017,38(2)

陕西省某山羊养殖场发生一起山羊鼻内肿瘤病,通过流行病学和临床症状调查、病理剖检、病理切片检查进行初步诊断。其次根据GenBank收录的山羊地方性鼻内肿瘤病毒基因组序列设计1对特异性引物,通过PCR方法从肿瘤组织中扩增获得目的片段并测序。序列比对分析表明,该目的基因和山羊地方性鼻内肿瘤病毒高度相似,最终确定该病为山羊地方性鼻内肿瘤病毒引起的山羊地方性鼻内肿瘤(ENT)。  相似文献