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贝氏隐孢子虫在鸡胚绒毛尿囊膜上发育过程的研究 总被引：1，自引：0，他引：1
借助微分干涉显微镜（NIC）对贝氏隐孢子虫（C. Baileyi）在鸡胚CAM上的发育过程进行了研究。整个发育周期为96小时，全部发育过程包括：脱囊 — 裂殖生殖 — 配子生殖 — 孢子生殖，共4个阶段。裂殖生殖共产生3代裂殖体，在第Ⅰ、Ⅲ代裂殖体中分别含有8个裂殖子，在第Ⅱ代裂殖体中含有4个裂殖子。孢子化过程在CAM内胚层上皮细胞表面的带虫空泡内完成，并产生薄壁型和厚壁型两种卵囊。首次提出虫体具有群体寄生现象和同步发育特征；描述了C. Baileyi的运动期虫体离开母体和发育为滋养体的动态变化过程；应用由粪便中纯化的卵囊直接感染鸡胚成功 。并用37℃水浴脱囊，脱囊率达60%左右，表明温度对隐孢子虫的脱囊具有重要作用，无需胰酶和牛胆酸钠的参与。动物回归试验表明：C. Baileyi不能经胚胎途径造成感染，在CAM上发育的C. Baileyi卵囊对雏鸡具有较强的感染性。 相似文献
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作为5年期专项规划之一的省、市级“国土资源信息化规划”,在实践中发挥的作用仍然比较有限,其中既有人们对该规划的认识不足因素,也有规划编制与实施过程本身的原因.该研究结合实际参与的有关规划编制与实施跟踪,分析了该专项规划的目标定位、操作流程以及目前存在的一些问题,再通过借鉴现代软件业的“统一过程管理(Unified Process,UP)”方法,提出了省、市级国土资源信息化5年期规划从规划立项、调研分析、规划编制、反馈评审、跟踪实施与评估总结的“规划生命周期管理”框架.以该框架为基础,结合广东省的实际情况,对广东省国土资源信息化“十三五”规划的相关内容进行了初步探讨. 相似文献
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H. C. Biggs E. McClain G. L. Muller M. Anthonissen K. M. Hare 《Preventive veterinary medicine》1998,33(1-4):267-282
A model was developed for predicting outbreaks of Oestrus ovis throughout the main sheep farming areas of Namibia. Pupal developmental periods were studied, concomitant air and soil temperatures enabling degree-day calculations to be made for prediction of adult fly strike. Monitoring of larval infection established seasonal incidence of O. ovis infestation and acted as verification of predictions. The establishment of relevant isothermal maps for Namibia made possible extrapolation from the several study sites to the entire sheep farming area. Retrospective and actual predictions of the important first peak after winter were considered accurate enough to recommend timing of control measures. No evidence of overwintering of first stage instars was found, the strategy used instead being extended pupation. Adult fly energy reserves were determined. 相似文献
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针对集中供气型沼气工程加温需求和地源热泵式系统存在地下侧土壤温度回补问题,提出了太阳能-地源热泵复合式沼气池加热系统(ISGSHPS),并从经济和环保两方面将该系统与地源热泵和电热膜加热系统进行分析比较得出系统的最优太阳能集热面积。结果表明:最优集热面积主要与每年总加热时间、电价有关。系统最经济加热时间段为每年10月至次年5月;在电价低于0.5元/(kW.h)时,ISGSHPS不如单独的地源热泵系统经济;在电价0.5~1.0元/(kW.h)和高于1.0元/(kW.h)时,ISGSHPS的最优集热面积分别为24 m2和32 m2。目前,最合理的太阳能投资面积为24 m2,生命周期为20年的ISGSHPS相对地源热泵和电热膜系统总节约费用分别为10 830元和59 244元,CO2减排量约为74 t和266 t,有较大的投资潜力。 相似文献
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Bernard Tivoli Sabine Banniza 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):59-76
Asochyta blights of grain legumes are caused by fungal pathogens in the genus Ascochyta. Different species infect the different legume species, and in pea three species including Phoma medicaginis var. pinodella have been implicated in ascochyta blight. The impact of the diseases varies between crops, countries, seasons and cropping
systems, and yield loss data collected under well-defined conditions is scarce. However, ascochyta blights are considered
major diseases in many areas where legumes are grown. Symptoms appear on all aerial parts of the plant, and lesions are similar
for most of the species, except for M. pinodes and P. medicaginis var. pinodella. Infected seed, stubble and/or air-borne ascospores are major sources of primary inoculum. Their importance varies between
species and also between regions. All Ascochyta spp. produce rain-splashed conidia during the cropping season which are responsible for the spread of the disease within
the crop canopy. Only in pea are ascospores involved in secondary disease spread. Limited data suggests that Ascochyta spp. may be hemibiotrophs; however, toxins characteristic for necrotrophs have been isolated from some of the species. Modelling
of ascochyta blights is still in the developmental stage and implementation of such models for disease forecasting is the
exception. 相似文献
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