旋毛虫起源、进化及其宿主的感染来源与途径

毛形属在距今27 500万年前从毛形科中正式分化出来,各旋毛虫种间的遗传差异形成于距今的1 500万~2 000万年间。对亚洲和欧洲的共110个Trichinella spiralis地理隔离株的线粒体基因分析结果显示,欧洲地理株间仅存1个碱基差异,具有高度的一致性,而亚洲地理株间则具有8个碱基差异,存在明显的种内差异。依据线粒体累积变异速率计算,T.spiralis由亚洲传播至欧洲的时期大约在60 00年~16 000年以前。不同种旋毛虫对动物的感染具有一定的异嗜性,而宿主感染旋毛虫的途径则主要来源于水平传播,即食用感染有虫体的肉类;机械性传播,即经粪便、土壤、废水、食腐性昆虫的机械性传播;垂直传播,目前在人类、豚鼠中有检出报道。     

中国奶牛养殖生产布局时空演变分析

本研究基于2001—2017年中国奶牛存栏量统计数据,运用奶牛养殖布局指数、奶牛养殖重心模型和空间自相关模型分析方法,分析中国奶牛养殖生产布局在时间和空间上的演变过程和特征。结果表明:①东北和内蒙古产区奶牛存栏量呈下降趋势,华北产区保持稳定上升,西部产区缓慢上升,南方产区和大城市周边产区呈下降趋势;内蒙古、新疆和黑龙江稳居奶牛养殖主产区的主导地位,但优势逐渐减弱,以河南为代表的新兴产区奶牛养殖发展迅速。②奶牛养殖重心呈现出先向东南方向移动再向西南方向移动的演变趋势。③省际间奶牛存栏量具有全局空间正相关性且相关性不断增强,并已在黑龙江、山西、贵州、广东、海南、云南、广西、河南、陕西、青海、吉林、辽宁和河南出现局部地理集聚现象。最后,提出促进我国奶业发展的相关建议。     

Analysis on Genetic Diversity and Phyletic Evolution of mtDNA Cytb Gene in Zhongdian Yak

In order to investigate the genetic diversity and the origin of evolutionary relationship of Zhongdian yak,we analyzed the complete sequence of 15 individuals Cytb gene,its sequence polymorphism was analyzed,and the phylogenetic tree was constructed.The results showed that the length of the nucleotide sequence were 1 140 bp,with nucleotide frequencies of 26.3%,31.8%,13.1% and 28.8% for T,A,G and C,respectively.Three haplotypes were identified of 15 individuals,with 3 polymorphic sites,including two conversions,one transversion,haplotype diversity was 0.2571 and nucleotide diversity was 0.00035.Phylogenetic analysis suggested that Zhongdian yak and Bos mutusc clustered firstly,then gathered with Bison bison,which indicated that there were high genetic similarity and closer genetic relationship,genetic similarity with other cattle genus was relatively low.Combining with the proof of molecular biology and paleontology,the result supported the point that Bos grunniens and Bos mutus were classified as an alone genus in Bovinae.     

基因2型猪繁殖与呼吸综合征病毒的遗传变异与演化

作为一种RNA病毒,猪繁殖与呼吸综合征病毒(PRRSV)极易变异,具有快速演化且易与其他毒株发生重组的特性,不同PRRSV毒株又存在着明显的致病性表型差异,异源毒株间交叉保护较差,这也是迄今为止PRRSV未得到有效控制的最主要的原因之一,PRRSV给全球养猪业带来了不可估量的经济损失。自上世纪80年代发现以来,基因2型PRRSV不断变异与演化,根据ORF5基因遗传进化分析,其被划分为9个谱系,我国主要以谱系1,3,5,8为主。本文从自然流行毒株、疫苗演化毒株、重组毒株3个方面对基因2型PRRSV的遗传变异与演化进行了综述,以期为PRRSV分子流行病学的研究及其免疫防控提供参考依据。     

鸡源致病性奇异变形杆菌的分离鉴定与遗传进化分析

为了解鸡源奇异变形杆菌的耐药情况、致病力和遗传特征,本试验从凉山地区分离得到2株细菌（YLF1、WS）,通过培养特征、镜检特征和16S rRNA序列测定对分离菌进行鉴定及致病性试验;采用（K-B）法检测分离菌对14种常用抗生素（包括β-内酰胺类、头孢烯类、氨基糖苷类、四环素类、氟喹诺酮类、大环内酯类）的敏感性;并与GenBank中公布的21种不同来源的变形杆菌16S rRNA基因序列进行遗传进化分析。结果表明,YLF1、WS菌株均具有迁徙性和β-溶血生长特征,镜检为革兰氏阴性长短不一的杆菌或球菌,经16S rRNA基因鉴定与GenBank中奇异变形杆菌同源性均在99%以上,YLF1、WS菌株确定为奇异变形杆菌,均表现为多重耐药,耐药率分别为78.6%（11/14）和71.4%（10/14）;雏鸡致死率均为80%;YLF1、WS菌株与日本人体分离株、中国新疆黄牛分离株和中国广东土壤分离株同源性最高,达99.9%;与来自中国河南、中国新疆及印度的鸡源奇异变形杆菌同源性较高（98.9%~99.3%）,遗传关系密切。表明凉山地区鸡群中存在奇异变形杆菌感染,分离株有较高的致病力和较强的耐药性,也提示分离菌可能来源于环境、感染鸡或其他动物,同时存在人畜共患的潜在危险。     

动物营养学研究方法进展

综述了动物营养学研究方法的发展历程,即由传统动物营养学向系统动物营养学的发展,以及各学科在动物营养研究方法中的应用。     

中国古代音乐的演变及审美特征

中国古代最早形成并自觉走向成熟的是音乐。"天人合一"的中和美,色彩斑斓的音色美,超逸、洒脱的空灵美,是中国古代音乐最主要的审美特征。     

The origin,evolution, cultivation,dissemination, and diversification of Asian and African rices

Summary Available evidences drawn from biosystematics, evolutionary biology, biogeography, archaeology, history, anthropology, paleo-geology and paleo-meteorology are pooled to reconstruct the series of events that led to the cosmopolitan cultivation of the Asian cultivated rice (O. sativa) and the regionalized planting of the African cultigen (O. glaberrima) in West Africa. The genus Oryza originated in the Gondwanaland continents and, following the fracture of the supercontinent, became widely distributed in the humid tropics of Africa, South America, South and Southeast Asia, and Oceania. The two cultivated species have had a common progenitor in the distant past. Parallel and independent evolutionary processes occurred in Africa and in Asia, following the sequence of: wild perennialwild annualcultivated annual. The weed races also contributed to the differentiation of the cultivated annuals. The corresponding members of the above series are O. longistaminata Chev. et Roehr., O. barthii A. Chev., O. glaberrima Steud., and the stapfii forms of O. glaberrima in Africa; O. rufipogon Griff., O. nivara Sharma et Shastry, O. sativa L., and the spontanea forms of O. sativa in Asia.The differentiation and diversification of the annuals in South Asia were accelerated by marked climatic changes following the last glacial age, dispersal of plants over latitude or altitude, human selection, and manipulation of the cultural environment.Cultivation of rice began in many parts of South and Southeast Asia, probably first in Ancient India. Cultural techniques such as puddling and transplanting were first developed in north and central China and later transmitted to Southeast Asia. Wetland culture preceded dryland culture in China, but in hilly areas of Southeast Asia, dryland cultivation is older than lowland culture. The planting method progressed from shifting cultivation to direct sowing in permanent fields, then to transplanting in bunded fields.Widespread dispersal of the Asian cultigen led to the formation of three eco-geographic races (Indica. Sinica or Japonica, and Javanica) and distinct cultural types in monsoon Asia (upland, lowland, and deep water). Varietal types changed readily within the span of a millenium, largely due to cultivators' preferences, socio-religious traditions, and population pressure. Genetic differentiation developed parallel to the ecologic diversification process.The African cultigen developed later than the Asian cultigen and has undergone less diversification. The wild races in South America and Oceania retain their primitive features mainly due to lack of cultivation pressure or dispersal.Both the African and Asian rices are still undergoing evolutionary changes at habitats where the wild, weed, and cultivated races co-exist.     

初探草坪起源与演化,兼论草坪的概念

草坪为一类特殊的草地。草坪起源的关键在于草坪草的分化发生。草坪草、草坪起源及早期演化 ,都是地史时期内 ,特定的气候 -生物 -土壤协同演化 (Coordinateevolution)的产物。移栽自然草坪 ,开始向人工草坪过渡。人工草地的出现 ,通过“重牧”、“刈割”等导致人工草坪的诞生 ;剪草机的发明标志着现代草坪的降临     

基于翻转课堂模式的园林史教学改革探索

FC模式即"翻转课堂",也称为"颠倒课堂",是利用信息技术"翻转"知识传授和知识内化2个学习过程的全新教学模式。园林史是风景园林专业的重要专业基础课程,笔者经过历年园林史课程教学实践经验的积累,结合地区实际,探索了基于翻转课堂理念的园林史教学模式改革的实施途经,以期合理地解决好传统园林史教学革新中的相关问题。通过改进多媒体教学方式,高效利用课堂时间,充分发挥学生的学习主动性,进而提高教学效果和学生的学习兴趣,为园林史教学改革提供参考。