3个马群感染马泰勒虫的分子病原学调查

试验采用显微镜观察、PCR和竞争性酶联免疫吸附试验(competitive enzyme-linked immunosorbentassay,cELISA)等方法对贵州矮马、西南马和伊犁马的马泰勒虫病的感染状况进行研究。结果显示,从32份新鲜的血液涂片中,观察到形态完整的马泰勒虫(Theileria equi)虫体,检出率12.5%。从贵州矮马、西南马及伊犁马3个马群血液总DNA中都检测到马泰勒虫的18S rRNA基因片段,与已知序列的同源性为97%~100%;相比之下,贵州矮马与伊犁马的阳性率相近,分别为76.62%和73.81%,西南马较低,仅为33.33%。另外,经cELISA检测,与伊犁马(31.71%)相比,贵州矮马和西南马血液中抗马泰勒虫抗体的阳性率较低,分别为24.68%和12.12%,并与两个马群的血液理化指标存在一定的联系:与中性细胞数量、γ-谷氨酰转移酶和肌酸激酶的含量呈弱正相关;与红细胞、白细胞、血小板、淋巴细胞数量及血红蛋白含量呈弱负相关。这些研究结果提示3个马群中均存在较高比例的马泰勒虫感染。     

马泰勒虫和驽巴贝斯虫半胱氨酸蛋白酶截短基因的克隆表达及其生物信息学分析

旨在克隆、表达马泰勒虫（Theileria equi）和驽巴贝斯虫（Babesia caballi）半胱氨酸蛋白酶（cystein protease,CP）基因,并对其进行生物信息学预测和分析。提取马泰勒虫和驽巴贝斯虫的DNA,以此为模板扩增目的基因。利用克隆技术和原核表达系统克隆表达CP,用尿素透析法进行纯化。通过Dot blot验证其与相应阳性血清特异性反应。应用MAGA软件和Prot Param、TMHMM、SignalP-5.0、Antibody Epitope Prediction、SYFPEITHⅡ、ProPred及EzMol^2.1等在线分析软件分析T.equi-CP和B.caballi-CP的基因及其蛋白序列。成功构建了重组质粒GST-T.equi-CP和GST-B.caballi-CP,经SDS-PAGE试验结果显示该基因表达的蛋白以包涵体形式高效表达,并能与相应阳性血清特异性反应。对T.equi-CP和B.caballi-CP基因编码蛋白进行系统发育分析发现,与其他原虫物种相比,系统发育分析结果与其原生动物学分类结果一致。经生物信息学分析预测显示,两个CP蛋白为亲水性蛋白,无跨膜区,不属于跨膜蛋白,无Th细胞表位,在细胞质、线粒体和细胞核中定位较多。其中T.equi-CP蛋白的相对分子质量为29 948.60,等电点为5.53,稳定系数为22.50。B.caballi-CP蛋白的相对分子质量为14 603.62,等电点为8.54,稳定系数为47.69,有信号肽区域。T.equi-CP和B.caballi-CP蛋白具有良好的反应原性,作为亲水性膜外蛋白,无Th细胞表位,在细胞质、线粒体和细胞核中定位较多等,可能说明CP在马梨形虫逃避宿主免疫反应,参与增殖、分化及程序性细胞死亡等发挥作用。本研究为T.equi-CP和B.caballi-CP蛋白的功能研究与马梨形虫的致病机制研究提供了理论依据。     

Prokaryotic Expression of the Cysteine Proteinase Gene of Xinjiang Strain of Theileria equi/Babesia caballi and Its Bioinformatics Analysis

This study aimed to clone and express cysteine proteinase (CP) gene of Theileria equi and Babesia caballi. The CP proteins were analyzed using bioinformatics tools and online databases. The total DNA of T. equi and B. caballi as the template sequence for PCR. The CP genes were cloned, expressed using the cloning technique and prokaryotic expression system, respectively. Then the recombinant CP (rCP) proteins were purified by Urea dialysis. Finally the specific reaction of polyclonal horse anti-CP serum with rCPs was analyzed through Dot blot method. The CPs were predicted and analyzed by the software MAGA, Prot Param, TMHMM, SignalP-5.0, Antibody Epitope Prediction, SYFPEITHⅡ, ProPred and EzMol^2.1 respectively. The CP genes were successfully amplified from DNA of T. equi and B. caballi and expressed in the inclusion body fractions, Dot blot assay indicated that the recombinant protein could react with polyclonal horse anti - CP serum. Compared with T. equi-CP and B. caballi-CP, different protozoon CP genes were highly conserved in evolution, and phylogenetic analysis results were consistent with their protozoon taxonomy. The bioinformatics analysis revealed that two CPs are the hydrophilic protein instead of a transmembrane one, no transmembrane domain, no Th cell epitope was found, and more localized in the cytoplasm, mitochondria and nuclei. The relative molecular weight (MW) of T. equi-CP was 29 948.60, the theoretical isoelectric point (pI) was 5.53, stability coefficient was 22.50; B. caballi-CP’MW was 14 603.62, the theoretical pI was 8.54, stability coefficient was 47.69, but signal peptide was contained. The CPs have good reactionogenicity, as the hydrophilic extracellular proteins with no Th cell epitope, and more localized in the cytoplasm, mitochondria and nuclei, which helped T. equi and B. caballi avoid host immune response outside the cell membrane and the CPs involved in proliferation, differentiation and programmed cell death. In conclusion, a theoretical basis was provided for the study on CP’s functions and the pathogenesis of T. equi and B. caballi.     

利用微卫星标记研究贵州矮马和伊犁马的遗传多样性

试验通过9个微卫星座位对贵州矮马和伊犁马2个品种共84匹马进行了遗传多样性检测,以8%非变性聚丙烯酰胺凝胶电泳分离PCR扩增产物,并用银染法显色,计算各微卫星位点的等位基因频率、有效等位基因数(Ne)、杂合度(H)和多态信息含量(PIC)。结果表明,9个微卫星座位中COR059检出的变异最大,AHT040的变异最小;伊犁马的Ne、H和PIC的平均值高于贵州矮马;2个群体的平均遗传分化系数为0.041。说明2个品种都有丰富的遗传多样性,贵州矮马的基因较伊犁马更为纯合。     

中国不同地区羊吕氏泰勒虫分子流行病学调查及遗传进化分析

为了解吕氏泰勒虫在中国不同地区山羊和绵羊中的流行情况,本研究应用基于吕氏泰勒虫18S rRNA基因位点的PCR检测方法,对采自中国河南、甘肃、陕西、山西、贵州、云南、新疆7个地区的281份羊血液样品进行检测,并对阳性样品测序以进行序列分析。结果显示,羊吕氏泰勒虫总感染率为35.23%（99/281）。不同采样点羊吕氏泰勒虫感染率差异极显著（P<0.01）,其中河南省羊吕氏泰勒虫感染率最高（98%,49/50）,新疆最低（0）。绵羊和山羊吕氏泰勒虫感染率分别为51.67%（31/60）和30.77%（68/221）,差异极显著（P<0.01）;放牧羊吕氏泰勒虫感染率（41.55%,86/207）极显著高于舍饲羊（17.57%,13/74）（P<0.01）;羊吕氏泰勒虫感染率在春、夏、秋及冬四季分别为56.00%（28/50）、42.75%（59/138）、9.43%（5/53）和17.50%（7/40）,差异极显著（P<0.01）;≥ 12月龄和<12月龄羊吕氏泰勒虫感染率分别为33.50%（67/200）和39.51%（32/81）,差异不显著（P>0.05）。此外,遗传进化分析表明,本研究获得的羊吕氏泰勒虫分离株与中国流行的吕氏泰勒虫分离株同源性高达99.60%以上,且位于同一分支上。本研究为进一步了解中国不同地区羊吕氏泰勒虫的流行现状及分布提供了重要参考依据。     

贵州矮马血清蛋白的多态性研究

以西南马为对照,采用非变性聚丙烯酰胺凝胶电泳技术对31匹贵州矮马的转铁蛋白(TF)、白蛋白(Alb)、α^1-B糖蛋白(AlB)3种血清蛋白进行了多态性研究。结果表明,AlB位点呈现单态,TF、Alb蛋白位点均表现出不同程度的多态性。Alb位点共发现6种蛋白型,对应3个等位基因,贵州矮马Alb位点的基因频率分别为A(0.2097)、B(0.5645)、C(0.2258);TF位点共发现8种蛋白型对应5个等位基因,贵州矮马TF位点的基因频率分别为A(0.0484)、B(0.5806)、C(0.1129)、D(0.1452)、E(0.1129)。Alb、TF位点的多态信息含量(PIC)和遗传杂合度均较大,说明贵州矮马的遗传多样性较高,具有较大的选育空间。但是贵州矮马在白蛋白及转铁蛋白位点的杂合度均低于西南马,说明在相对闭锁的环境中生存的贵州矮马,保持了较为纯净的原始基因库。贵州矮马的Alb和TF的个体识别率及累积非父排除率均较高,提示这两个蛋白的多态性可应用于贵州矮马的谱系鉴定和个体鉴别。     

黑色素皮质激素受体1基因248位点多态性与中国马品种毛色的相关性分析

在欧洲马品种中,黑色素皮质激素受体1(melanocortin receptor 1,MC1R)基因第248位碱基有C/T多态性,纯合的T248位点决定欧洲马的栗毛色。针对MC1R基因的248位点设计了2对特异性引物,采用等位基因特异性PCR技术,研究3个中国马品种MC1R基因型与栗色毛之间的关系。经扩增获得两种DNA片段,克隆测序后证明,扩增片段确为MC1R基因,两种DNA片段序列在基因的248位点的确呈现C/T多态性,但检测126份贵州矮马、西南马和新疆伊犁马血液样本,全部为杂合基因型(Ee),其中包括栗毛、黑毛、骝毛3种单毛色及3种复毛色。这些研究结果提示,MC1R基因中248位点的多态性与国内3个马品种的栗色毛之间没有直接的相关性。     

The use of an enzyme-linked immunosorbent assay for tropical theileriosis research in Morocco

An enzyme-linked immunosorbent assay (ELISA) using sonicated purified Theileria annulata piroplasms was compared with an indirect immunofluorescent antibody test (IFAT) during a vaccination trial in cattle to test different doses and passage numbers of an attenuated T. annulata-infected lymphoblastoid cell-line, and also with Giemsa-stained blood smears during an epidemiological field study of tropical theileriosis in Morocco. The sensitivities of both the ELISA (0.56) and the IFAT using T. annulata piroplasm antigen (0.56) were lower than the IFAT using schizont antigen (0.94) for detecting serum antibodies from 18 cattle immunised 38 days previously with cell-line. The ELISA was, however, the most sensitive test after 180 days (0.50 compared with 0.06 for the piroplasm IFAT and 0.39 for the schizont IFAT), and each test detected antibodies in all sera after challenge with live T. annulata sporozoites. There were minor differences in the ability of blood smear examinations and the ELISA to detect infected and uninfected cattle in the field study at the start and end of the disease season. Initially, the sensitivity and specificity of blood smears were both 0.96 and for the ELISA were 0.83 and 0.86, whereas at the end of the season sensitivity and specificity of blood smears were 0.96 and 0.86 and for the ELISA were 0.95 and 0.94. The specificity of the ELISA was affected by the presence of calves with colostral antibodies, and if these were disregarded the specificities before and after the season were 0.94 and 1.00.     

不同用途马肢体各部位比例差异性分析研究

本试验通过测定纯血马×伊犁马、奥尔洛夫马×伊犁马、俄罗斯速步马×伊犁马和汉诺威马4个类型马细分体尺,并计算各体尺比例及体尺指数等指标,分析各体尺、体尺指数及各比例差异性。结果表明,在体高、体长、胸围、管围、颈长、肱骨长、背长、腰椎长、尻长、尻高、股骨长和胫骨长等体尺方面,纯血马×伊犁马、奥尔洛夫马×伊犁马、俄罗斯速步马×伊犁马均极显著低于汉诺威马（P<0.01）;体躯指数方面,纯血马×伊犁马显著高于奥尔洛夫马×伊犁马（P<0.05）;肱骨长/背长、股骨长/背长和胫骨长/背长方面,纯血马×伊犁马、奥尔洛夫马×伊犁马、俄罗斯速步马×伊犁马均极显著低于汉诺威马（P<0.01）;奥尔洛夫马×伊犁马和俄罗斯速步马×伊犁马之间所有指标差异均不显著（P>0.05）。本试验结果表明不同用途马匹体型结构具有一定差异性,为不同用途马匹的培育提供数据参考。     

Difference Analysis of Body Proportion in Different Uses Horse Breeds

Measuring subsection body measurements of Thoroughbred×Yili horses,Orlov trotter×Yili horses,Russia trotter×Yili horses and Hanoverian horse,and calculated the proportion and index,analysing differences in each body measurement,index and proportion.The results showed that the body height,body length,chest circumference,cannon bone circumference,neck length,humerus length,back length,lumbar spine,rump length,rump high,thighbone length and tibiae length of Thoroughbred×Yili horses,Orlov trotter×Yili horses and Russia trotter×Yili horses were extremely significantly lower than Hanoverian horse (P<0.01),the trunk index of Thoroughbred×Yili horse was significantly higher than Orlov trotter×Yili horses (P<0.05),the humerus length/back length,thighbone length/back length and tibiae length/back length of Thoroughbred×Yili horses,Orlov trotter×Yili horses and Russia trotter×Yili horses were extremely significantly lower than Hanoverian horse (P<0.01),all body measurements of Orlov trotter×Yili horses had no significant difference with Russia trotter×Yili horses (P>0.05).The experiment results showed that the difference in body structure of horses for different uses could provide data reference for breeding these horses.     

伊犁马MyoG基因外显子1多态性与肉质性状及肌纤维性状关联分析

为寻找伊犁马肉质性能的分子标记,试验以38匹伊犁马为材料,测定肉质性状（失水率、熟肉率、剪切力）和肌纤维性状（肌纤维横截面积、肌纤维直径、肌纤维密度）,利用PCR直接测序法检测肌细胞生成素（meyogenin,MyoG）基因外显子1在伊犁马群体中的多态性,并对MyoG基因SNPs不同基因型与肉质、肌纤维性状进行关联分析。结果表明,MyoG基因外显子1检测出5个突变位点,分别为SNP1（g.31187343 A>C）、SNP2（g.31187333 G>A）、SNP3（g.31187132 C>T）、SNP4（g.31187105 C>G）和SNP5（g.31187099 C>T）,其中SNP1为错义突变,碱基A突变为C使得氨基酸由苏氨酸突变为脯氨酸,其他位点均为无义突变。SNP3和SNP4为中度多态位点,SNP1和SNP2为低度多态位点,这4个位点均处于Hardy-Weinberg平衡状态。MyoG基因外显子1中SNP1和SNP4不同基因型个体失水率、熟肉率、肌纤维横截面积、肌纤维直径、肌纤维密度差异显著（P<0.05）;SNP3不同基因型个体熟肉率、肌纤维横截面积、肌纤维密度差异显著（P<0.05）;SNP2不同基因型个体各指标差异均不显著（P>0.05）。综上,伊犁马MyoG基因外显子1检测到5个多态位点,其中SNP1（g.31187343 A>C）、SNP3（g.31187132 C>T）和SNP4（g.31187105 C>G）位点不同基因型对肉质及肌纤维性状有显著影响,这些位点可作为伊犁马肉质性能潜在分子标记。     

不同妊娠状态伊犁马心率变异性变化规律研究

【目的】研究流产伊犁马与正常分娩伊犁马在妊娠期心率变异性(HRV)的变化规律,以防止不良妊娠结局的发生。【方法】选取妊娠时间为29孕周的伊犁马21匹(其中流产5匹,正常分娩16匹)及7匹空怀伊犁马,分别在妊娠中期第30孕周,妊娠后期第45孕周及分娩前后1天对母马进行24 h HRV采集,包括时域指标：全部R-R间期的平均值(Mean RR)、全部R-R间距的标准差(SDNN)、平均心率(Mean HR)、相邻R-R间期差值的均方根(RMSSD)、相邻R-R间距差>50 ms的个数(NN50)和相邻R-R-间距差>50 ms的个数占总心跳次数的百分比(pNN50);频域指标：极低频率(VLF)、低频功率(LF)和高频功率(HF);非线性指标：全部R-R间距的标准差(Y)(SD1)、全部R-R间距的标准差(X)(SD2)。【结果】时域指标中,流产组和正常分娩组Mean RR、SDNN、RMSSD、NN50、pNN50极显著或显著低于空怀组(P<0.01;P<0.05),Mean HR极显著高于流产组和正常分娩组(P<0.01);频域指标中,流产组和正常分娩组H...     

Epidemiology of theilerioses in the Trans-Mara division, Kenya: Husbandry and disease background and preliminary investigations on theilerioses in calves

All the calves born (116) into 3 Maasai cattle herds in the Trans-Mara Division of Kenya, between August 1978 and October 1979, were recruited into a monthly health study which concentrated on theileriosis. Twenty-two of the calves died before they were 6 months of age, but the mortality only increased to 25% by the time the calves reached 18 months of age. The mean birth weight of calves was 17.5 kg while at 190 days post-birth the mean weight was 53.4 kg. The main causes of mortality were starvation (7.8%), neonatal diarrhoea (2.6%), chronic indigestion (2.6%) and theileriosis (2.6%) due to Theileria parva and T. mutans infections. The calves were infected with ticks from birth (mostly Rhipicephalus appendiculatus and Amblyomma spp.) and the first Theileria schizonts were detected on Day 17 post birth and reached a maximum of 18.4% of calves in the 11th week post-birth. Seasonal peaks of macroschizont incidence occurred in February and July. All calves had patent Theileria piroplasm infections by the time they were 5 months old and 44% had shown patent Theileria macroschizont infections by 6–7 months of age. Generally low parasitosis of Theileria piroplasms and schizonts occurred. Serology using the indirect fluorescent antibody test showed a high proportion of calves received antibodies against T. mutans and T. parva from their dams by way of colostrum. The majority of calves also had active antibody responses against T. mutans and T. parva by the time they were 6 months of age. There was a correlation between the pre-patent period of piroplasms and active antibody responses to T. mutans and between the prepatent period of schizonts and an antibody response to T. parva. Eighteen older calves developed T. velifera infections. “Turning sickness” due to Theileria infection in the brain was detected in older cattle. Other blood parasites such as Trypanosoma vivax, T. congolense, Anaplasma marginale and Babesia bigemina occurred at patent levels at a lower incidence than Theileria spp. and did not cause disease problems in the calves. The calf population was highly resistant to theileriosis since they had a 100% morbidity, but only 2.6% mortality. Theileria infections would appear to have an important effect on the growth of calves but this and many aspects of the epidemiology of theileriosis in the area required more intensive sampling.     

马生长激素基因多态性与体尺指标之间的关联性分析

为研究广西德保矮马、百色马和新疆伊犁马的生长激素(GH)基因多态性与体尺指标之间的相关性,本实验利用PCR-SSCP技术分析3个品种277匹马GH基因5′侧翼区、第3外显子、第4外显子、第5外显子的遗传多态性。结果表明:只有GH基因第5外显子出现多态性,表现为AA、BB和AB 3种基因型,其他片段未发现多态性。群体遗传学分析表明,等位基因A和B的基因频率相等;Hardy-Weinberg平衡检验显示,3个品种马均处于非平衡状态;它们的多态信息含量均为中度多态。统计分析表明,GH基因第5外显子的基因型与3个品种马体尺指标之间无显著相关性。     

Effects of Four Kinds of Diets on Nutrient Digestion,Metabolism and Blood Biochemical Indexes of One-year-old Yili Horse

Effects of four kinds of diets on nutrient digestion and metabolism and blood biochemical indexes of one-year-old Yili horse were studied in this experiment.16 health horses(all males) with an average body weight of (227.38±16.48)kg and similar age (one-year old) were used in a staging and grouping experiment design.First stage had groupsⅠ and Ⅱ,second stage had groups Ⅲ and Ⅳ.The horses of group Ⅰ were fed with alfalfa 8 kg/d,pelleted concentrate 0 kg/d; The horses of group Ⅱ were fed with alfalfa 7 kg/d,pelleted concentrate 1 kg/d;The horses of group Ⅲ were fed with alfalfa 6.3 kg/d,pelleted concentrate 1.7 kg/d;The horses of group Ⅳ were fed with alfalfa 5.6 kg/d,pelleted concentrate 2.4 kg/d.Each stage lasted for 21 d (15 d pretrial period and 6 d trial period).The results showed that the digestibility of DM,OM,CP and P were increased with increasing of feed levels of pelleted concentrate,while the digestibility of NDF,ADF and Ca showed downtrend.DE and ME were significantly increased with increasing of feed levels of pelleted concentrate (P > 0.05).N retention and retention rate showed an increasing tendency,N retention and retention rate of groups Ⅲ and Ⅳ were extremely significant higher than those in group Ⅰ (P < 0.01).Ca retention and retention rate decreased with increasing of feed levels of pelleted concentrate,and Ca retention and retention rate of group Ⅰ were extremely significant higher than those in groups Ⅱ,Ⅲ and Ⅳ (P < 0.01).P retention was extremely significant increased with increasing of feed levels of pelleted concentrate (P < 0.01).There were no significant difference in the content of TP among all trial groups (P > 0.05),but the content of BUN in groups Ⅱ,Ⅲ and Ⅳ were lower than those in group Ⅰ (P > 0.05).Thus,comprehensive nutrient digestion and metabolism,blood biochemical indicators of four of kinds diets in one-year-old Yili horse,the requirement of crude protein,digestible protein,metabolizable energy,digestible energy were 14.28,9.16 g/(kg·BW) and 1.74,1.41 MJ/(kg·BW),respectively.     

4种日粮对1岁伊犁马消化代谢、血液生化指标的影响

试验旨在研究4种日粮对1岁伊犁马消化代谢、血液生化指标的影响。选用平均体重为(227.38± 16.48)kg的1岁伊犁马16匹,随机分为2组,每组8匹,采用分期分组的试验方法,分别为试验Ⅰ、Ⅱ、Ⅲ、Ⅳ组。试验Ⅰ组每匹马饲喂苜蓿干草8 kg/d、颗粒精料0 kg/d;试验Ⅱ组每匹马饲喂苜蓿干草7 kg/d、颗粒精料1 kg/d;试验Ⅲ组每匹马饲喂苜蓿干草6.3 kg/d、颗粒精料1.7 kg/d;试验Ⅳ组每匹马饲喂苜蓿干草5.6 kg/d、颗粒精料2.4 kg/d。进行21 d的消化代谢试验,其中预试期15 d,正试期6 d。结果表明,1岁伊犁马对干物质、有机物、粗蛋白质、磷的消化率随日粮中颗粒精料水平的增加呈增长趋势,而中性洗涤纤维、酸性洗涤纤维、钙的消化率呈下降趋势;消化能、代谢能随日粮中颗粒精料水平的增加呈增长趋势(P > 0.05);氮沉积量、氮沉积率随日粮中颗粒精料水平的增加而增长,其中试验Ⅲ、Ⅳ组氮沉积量、氮沉积率极显著高于试验Ⅰ组(P < 0.01);钙沉积量、钙沉积率随日粮中颗粒精料水平的增加而降低,且试验Ⅰ组极显著高于试验Ⅱ、Ⅲ、Ⅳ组(P < 0.01);磷沉积量随日粮中颗粒精料水平的增加而极显著增加(P < 0.01);各组血浆中总蛋白含量差异不显著(P > 0.05),但试验Ⅱ、Ⅲ、Ⅳ组血浆尿素氮含量均低于试验Ⅰ组(P > 0.05)。综合1岁伊犁马对4种日粮的消化代谢情况及血液生化指标,1岁伊犁马粗蛋白质适宜需要量为14.28 g/kg代谢体重,可消化蛋白适宜需要量为9.16 g/kg代谢体重,代谢能适宜需要量为1.74 MJ/kg代谢体重,消化能适宜需要量为1.41 MJ/kg代谢体重。     

Clearance of Theileria sergenti-infected bovine red blood cells in severe combined immune deficiency mice

Clearance of Theileria sergenti-infected bovine red blood cells (Bo-RBCs) from the blood circulation of severe combined immune deficiency (SCID) mice was studied to help understand the mechanisms of anemia developing in cattle infected with T. sergenti. For the clearance test, Bo-RBC samples having 2%, 58%, and 76% parasitemia and, as a control, parasite-free Bo-RBCs were prepared in the Bo-RBC-SCID mouse model. The T. sergenti-infected Bo-RBCs and the uninfected control Bo-RBCs were separately labeled with two, green and red, fluorescent dyes, mixed together, and injected intravenously into SCID mice. The blood samples collected at various time points were observed under a fluorescent microscope, and the numbers of green and red fluorescing RBCs were counted differentially to determine the clearance rates of T. sergenti-infected and uninfected Bo-RBCs. This test clearly demonstrated that the Bo-RBC samples having higher parasitemias were cleared faster from the blood circulation of SCID mice. The results suggest that the intravascular clearance system in SCID mice may have a mechanism by which T. sergenti-parasitized and non-parasitized Bo-RBCs are recognized and cleared differentially.     

Adaptation and validation of antibody-ELISA using dried blood spots on filter paper for epidemiological surveys of tsetse-transmitted trypanosomosis in cattle

The indirect enzyme-linked immunosorbent assay (ELISA) for the detection of anti-trypanosomal antibodies in bovine serum was adapted for use with dried blood spots on filter paper.

Absorbance (450 nm) results for samples were expressed as percent positivity, i.e. percentage of the median absorbance result of four replicates of the strong positive control serum.

The antibody-ELISA was evaluated in Zambia for use in epidemiological surveys of the prevalence of tsetse-transmitted bovine trypanosomosis. Known negative samples (sera, n=209; blood spots, n=466) were obtained from cattle from closed herds in tsetse-free areas close to Lusaka. Known positive samples (sera, n=367; blood spots, n=278) were obtained from cattle in Zambia's Central, Lusaka and Eastern Provinces, diagnosed as being infected with Trypanosoma brucei, T. congolense, or T. vivax using the phase-contrast buffy-coat technique or Giemsa-stained thick and thin blood smears. For sera (at a cut-off value of 23.0% positivity) sensitivity and specificity were 86.1 and 95.2%, respectively. For bloodspots (at a cut-off value of 18.8% positivity) sensitivity and specificity were 96.8 and 95.7%, respectively. The implications of persistence of antibodies following treatment or self-cure are discussed.     

新疆昭苏县不同季节和不同年龄段伊犁马消化道寄生虫感染情况的调查研究

试验旨在研究不同季节和不同年龄段伊犁马消化道主要寄生虫感染情况。在新疆昭苏县选取体重及健康状况相近的1岁（106匹）、2岁（116匹）及3岁（110匹）伊犁马,共计332匹,公母各半。分别于春季（4月）和秋季（10月）采集3个年龄的马匹粪便样品664份,每匹马2份（早、晚各1份）,用于寄生虫卵的鉴定和计数。结果表明,在不同年龄段春、秋两季伊犁马粪便中共鉴别出6种虫卵,分别是马圆线虫、毛圆线虫、细颈三齿线虫、马副蛔虫、马尖尾线虫、球虫,其中马圆线虫、毛圆线虫、细颈三齿线虫、马副蛔虫感染率较高。春季1岁、2岁、3岁伊犁马,马圆线虫感染率分别为98.11%、90.52%、88.18%;毛圆线虫感染率分别为95.28%、89.66%、97.27%;细颈三齿线虫感染率分别为85.85%、78.45%、87.27%;马副蛔虫感染率分别为46.23%、35.34%、29.09%。秋季1岁、2岁、3岁伊犁马,马圆线虫感染率分别为87.74%、69.83%、78.18%;毛圆线虫感染率分别为74.53%、79.31%、86.36%;细颈三齿线虫感染率分别为65.09%、68.10%、76.36%;马副蛔虫感染率分别为46.23%、35.34%、24.55%。由该试验结果可以得出,新疆昭苏县伊犁马感染率较高的寄生虫有马圆线虫、毛圆线虫、细颈三齿线虫及马副蛔虫;1岁马驹寄生虫感染率及虫卵数量普遍高于2岁和3岁马;春季寄生虫感染率普遍高于秋季。     

利用微卫星标记对宁强矮马和蒙古马遗传多样性的研究

通过8个微卫星位点的多态性检测对宁强矮马和蒙古马共83个个体进行了遗传多样性分析。计算各微卫星位点的等位基因频率、有效等位基因数(Ne)、多态信息含量(PIC)、杂合度(H)和F统计量。结果表明:8个微卫星座位中HMS2变异最大,HTG6变异最小;蒙古马的Ne、PIC、H的平均值均高于宁强马;总群体的平均遗传分化系数Fst为0.017(P<0.01),群体内近交系数Fis为0.171(P<0.01)。说明蒙古马和宁强矮马虽外形和性能上有很大差异,但在品种形成和进化上有着较近的遗传关系。