猪多杀性巴氏杆菌的分离鉴定及oppA基因遗传进化分析     

李红婕  董紫凡  车勇良  周伦江  王隆柏  白丁平 《中国畜牧兽医》2022,49(12):4786-4794

【目的】了解福建省猪场猪多杀性巴氏杆菌（Pasteurella multocida,Pm）的流行及oppA基因遗传进化情况。【方法】本研究采用细菌分离培养、生化试验、16S rRNA PCR扩增测序、PCR荚膜分型、oppA基因克隆及相似性分析、动物回归试验等方法对分离菌株进行鉴定和分析。【结果】本研究共分离到10株菌,分离菌在血平板上形成淡灰白色、湿润光滑、奶油露珠状菌落;分离菌株能酵解蔗糖、果糖、麦芽糖和甘露醇,不能分解葡萄糖、枸橼酸盐、乳糖、硫化氢等,与多杀性巴氏杆菌生化特性基本一致;分离菌株16S rRNA序列与GenBank中登录的多杀性巴氏杆菌相似性达99.9%以上,10株分离菌均为多杀性巴氏杆菌;PCR荚膜分型显示,6株分离菌为荚膜A型,4株为荚膜D型;基于oppA基因的遗传进化树显示,10株分离菌均位于同一分支内;动物回归试验结果显示,在24 h内攻毒小鼠死亡率较高（21/30）,分离菌有较强的致病力。【结论】福建省猪场猪多杀性巴氏杆菌流行菌株的荚膜血清型主要是A和D型,且大部分菌株都来源于共同的祖先,本研究结果丰富了猪多杀性巴氏杆菌的流行病学资料,并为该病的防控奠定基础。  相似文献   

非洲猪瘟疫苗研究进展     

李运娜  王冠  贾皓  戴晓光  苏胜杰  王旭红 《畜牧与饲料科学》2022,43(1):115-118

非洲猪瘟（African swine fever,ASF）是由非洲猪瘟病毒（African swine fever virus,ASFV）引起的家猪和野猪的急性、出血性传染病,强毒株感染猪的致死率接近100%,给养猪业造成巨大经济损失。ASFV在猪群中可以快速有效传播,在环境中可稳定存在,为ASF的防控带来了挑战。研究人员一直致力于ASF疫苗的研究,迄今为止,仍没有有效的疫苗投入市场。综述了ASF灭活疫苗、减毒活疫苗、亚单位疫苗、DNA疫苗、病毒活载体疫苗的研究情况,以期为ASF疫苗的有效研发提供参考。  相似文献   

A型塞尼卡病毒检测方法及疫苗研究进展     

王迁迁  于永乐  李月华  董雅琴  尼博  刘拂晓 《中国畜牧兽医》2022,49(6):2336-2346

A型塞尼卡病毒（Senecavirus A,SVA）也称为塞尼卡谷病毒（Seneca Valley virus,SVV）,属于小RNA病毒科塞尼卡病毒属成员。SVA主要引起猪的水泡性疾病,与口蹄疫、水泡性口炎、猪水泡病等临床症状相似,可导致新生仔猪急性死亡,严重影响养猪业发展。自2015年广东省发生SVA感染以来,中国多省份陆续有该病发生的报道。当前,中国因猪群缺乏针对SVA的免疫屏障,加之该病传染性较强,存在大范围暴发的潜在风险。如何有效防控SVA感染是迫切需要解决的问题。目前已开发出多种SVA诊断方法用于进行实验室及现场条件下早期的鉴别诊断。SVA的分离鉴定、原位杂交和免疫组化可用于检测病原体的存在及其与组织内形态学变化关系;血清学诊断方法包括基于不同结构蛋白的间接ELISA方法、竞争ELISA方法、均相光激化学发光免疫技术和病毒中和试验,用免疫学方法检测抗体有助于了解SVA感染进程,是临床诊断的主要手段;病毒核酸检测方法主要有PCR技术、等温扩增技术、基因组测序等分子生物学技术,在病毒感染的早期快速检测及检测新发病毒中具有重要作用。目前仍无商品化疫苗预防SVA感染,但科研人员已研发出了灭活疫苗、弱毒疫苗、核酸疫苗和亚单位疫苗等多种具有潜力的候选疫苗。笔者系统总结了SVA检测方法及疫苗研发的最新进展,以期为SVA感染的防控提供参考依据。  相似文献   

非洲猪瘟病毒感染后猪外周血淋巴细胞Toll样受体信号通路的lncRNA-mRNA分析     

陈世钰  崔帅  蒋亚君  鑫婷  王洋  郝玉欣  黄建新  郭晓宇  朱鸿飞  吴佳俊  贾红 《中国畜牧兽医》2022,49(7):2677-2687

【目的】丰富非洲猪瘟病毒（African swine fever virus,ASFV）感染后猪外周血淋巴细胞长链非编码RNA（long non-coding RNA,lncRNA）表达谱,并进一步挖掘影响Toll样受体信号通路的调控网络。【方法】试验动物感染ASFV,于第7天采集外周血并分离得到外周血淋巴细胞,运用Illumina高通量组学测序对外周血淋巴细胞中lncRNA进行测序,原始数据经处理后筛选获得差异表达的lncRNA,并进行靶基因预测,利用生物信息学方法对靶基因进行GO功能和KEGG信号通路富集分析,初步绘制与Toll样受体信号通路相关的lncRNA-mRNA调控网络,并对lncRNA-ENSSSCG00000041959在内的4个lncRNAs进行实时荧光定量RT-PCR验证。【结果】共筛选到73个差异表达的lncRNAs,其中上调表达lncRNAs 38个,下调表达lncRNAs 35个。GO功能分析结果显示,靶基因显著富集在调节免疫系统过程、防御反应、生物刺激、病毒反应和先天性免疫;KEGG信号通路富集分析显示,大部分靶基因与细胞循环、疾病及免疫应答有关,其中免疫相关信号通路有Toll样受体信号通路、TNF信号通路、产生IgA的肠道免疫网络等。进一步挖掘出lncRNA-ENSSSCG00000041959-RIPK1和lncRNA-ENSSSCG00000041959-IRAK1可能是影响Toll样受体信号通路的重要调控网络,实时荧光定量RT-PCR与测序结果一致。【结论】本研究初步鉴定出lncRNA-ENSSSCG00000041959-RIPK1和lncRNA-ENSSSCG00000041959-IRAK1可能是影响Toll样受体信号通路的lncRNA-mRNA调控网络,为进一步探索lncRNA调控ASFV感染机体免疫反应奠定了理论基础。  相似文献   

Tree and crop productivity in gliricidia/maize/pigeonpea cropping systems in southern Malawi     

P.W. Chirwa  C.R. Black  C.K. Ong  J.A. Maghembe 《Agroforestry Systems》2003,59(3):265-277

This study examined the hypothesis that incorporation of Gliricidia sepium (Jacq.) Walp.) (gliricidia), a fast-growing, nitrogen-fixing tree, into agroforestry systems in southern Malawi may be used to increase the input of organic fertilizer and reduce the need for expensive inorganic fertilizers. The productivity of maize (Zea mays L.), pigeonpea (Cajanus cajan L.) and gliricidia grown as sole stands or in mixed cropping systems was examined at Makoka Research Station (latitude 15° 30′ S, longitude 35° 15′ E) and a nearby farm site at Nazombe between 1996 and 2000. Treatments included gliricidia intercropped with maize, with or without pigeonpea, and sole stands of gliricidia, maize and pigeonpea. Trees in the agroforestry systems were pruned before and during the cropping season to provide green leaf manure. Maize yields and biomass production by each component were determined and fractional light interception was measured during the reproductive stage of maize. Substantial quantities of green leaf manure (2.4 to 9.0 Mg ha⁻¹ year⁻¹) were produced from the second or third year after tree establishment. Green leaf manure and fuelwood production were greatest when gliricidia was grown as unpruned sole woodlots (c. 8.0 and 22 Mg ha⁻¹ year⁻¹ respectively). Improvements in maize yield in the tree-based systems also became significant in the third year, when c. 3.0 Mg ha⁻¹ of grain was obtained. Tree-based cropping systems were most productive and exhibited greater fractional light interception (c. 0.6 to 0.7) than cropping systems without trees (0.1 to 0.4). No beneficial influence of pigeonpea on maize performance was apparent either in the presence or absence of gliricidia at either site in most seasons. However, as unpruned gliricidia provided the greatest interception of incident solar radiation (>0.9), coppicing may be required to reduce shading when gliricidia is grown together with maize. As pigeonpea production was unaffected by the presence of gliricidia, agroforestry systems containing gliricidia might be used to replace traditional maize + pigeonpea systems in southern Malawi. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

仿桑园优质土壤肥料的研究(Ⅲ)──仿桑园优质土壤肥料试验     

李茂贞  许乐春  张君启  赵才宝  王福平  田伟  谢广华 《河北林果研究》1996,(1)

以桑园优质土壤中主要矿质营养的数量及比例为基础，研制了仿优质土壤桑树专用肥料，按照山东省棕壤、褐土、潮土３大类土壤测定肥效，经过３ａ的小区试验、中试及推广，认为该肥能有效地提高桑叶产量并能改进叶质，经济效益较高。  相似文献   

沼肥对促进脐橙生长及提高产量与品质的效果研究   总被引：1，自引：0，他引：1  

胡永军 《林业调查规划》2004,29(2):102-104

对沼肥在脐橙上的施肥效果进行分析研究，得出沼肥对脐橙根、茎、叶的生长及花蕾的形成有明显的促进作用，对提高脐橙产量，增加糖分含量，改善果品品质，减少病虫害的发生有明显的作用。  相似文献   

Nitrogen mineralization patterns of leaf-twig mixtures from tropical leguminous trees     

M. Constantinides  J. H. Fownes 《Agroforestry Systems》1993,24(3):223-231

Green manure applications in alley cropping systems often include twigs despite their potential to absorb (immobilize) nitrogen (N). To assess the impact of twigs on net N mineralization or immobilization from hedge row cuttings, we separated cuttings fromCalliandra calothyrsus andGliricidia sepium into leaf-only, twig-only, and mixed (leaf + twig) fractions and incubated them with moist soil in the laboratory. Soil extractable inorganic N did no differ among treatments after two weeks, but after four and eight weeks was greatest in leaf-only, and least in twig-only treatments. After two weeks, extractable N from the leaf-only treatment rose steadily, while that from the twig-only and mixed treatments was variable due to periods of net mineralization and net immobilization. The pattern of variation in mixed treatments paralleled that of twig-only, indicating that net immobilization in the mixture was largely caused by the presence of twigs. Extractable N from the mixture was somewhat lower than that predicted from the sum of leaf-only and twig-only treatments. We conclude that twigs in green manure reduce short-term N availability to associated crops in agroforestry systems.  相似文献   

Organic Matter Added to Bareroot Nursery Beds Influences Soil Properties and Morphology of Fraxinus pennsylvanica and Quercus rubra Seedlings     

Anthony S. Davis  Douglass F. Jacobs  Kevyn E. Wightman  Zonda K. D. Birge 《New Forests》2006,31(2):293-303

Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings (Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha⁻¹ (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m³ ha⁻¹. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl). Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak, but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the proper balance can improve seedling morphological quality and positively influence soil chemical properties.  相似文献   

基于UPLC-MS/MS同时测定猪粪便中5种兽药残留量的研究     

顾欣 《中国兽药杂志》2015,49(10):32-35

为了建立同时测定猪粪便中二甲氧苄啶、磺胺对甲氧嘧啶、恩诺沙星、金霉素、泰乐菌素5种兽药残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法,样品经McIllvaineNa_2EDTA缓冲溶液提取,C18粉吸附杂质,HLB固相萃取小柱净化,浓缩富集后用0.1%甲酸甲醇溶液复溶,过滤上机,基质液外标法定量。结果显示,5种兽药在10~500μg/kg的质量浓度范围内线性良好,在添加浓度50~500μg/kg,平均回收率为53%~85%,RSD为1.87%~18.81%。该方法具有较好的准确度与精密度,能快速、准确测定猪粪便中5种兽药残留,为养殖环节实时监测兽药使用情况提供了技术支持。  相似文献