王玲玲,劉永杰,鄭海學(xué),張克山,劉湘濤
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山羊流產(chǎn)嗜衣原體廣東株的鑒定及分子特征分析
王玲玲,劉永杰,鄭海學(xué),張克山,劉湘濤
中國農(nóng)業(yè)科學(xué)院蘭州獸醫(yī)研究所,家畜疫病病原生物學(xué)國家重點(diǎn)實(shí)驗(yàn)室,國家口蹄疫參考實(shí)驗(yàn)室,蘭州730046
摘要:目的確診疑似羊衣原體感染的病例,分析羊衣原體分子特征。方法從廣東某羊場(chǎng)采集疑似羊流產(chǎn)嗜衣原體病例的子宮內(nèi)羊水,采用現(xiàn)場(chǎng)病理解剖觀察、病料觸片吉姆薩染色、顯微鏡觀察、特異性目的基因ompA擴(kuò)增和序列測(cè)定及遺傳進(jìn)化關(guān)系分析等方法進(jìn)行了該病例的確診及病原分子特征分析。結(jié)果現(xiàn)場(chǎng)解剖發(fā)現(xiàn)和羊流產(chǎn)嗜衣原體感染癥狀極其吻合,吉姆薩染色后顯微鏡觀察可見衣原體特有的特征,自病料中擴(kuò)增出特異性目的基因片段,表明該病例為山羊感染流產(chǎn)嗜衣原體引起?;蛐蛄羞z傳進(jìn)化分析表明該流產(chǎn)嗜衣原體(GenBank登錄號(hào)KP984478)與2013年公布的中國貴州分離株KF130872遺傳關(guān)系最近(同源性為99.1%),屬于同一進(jìn)化分支,與2002年公布的德國分離株AJ004873遺傳關(guān)系最遠(yuǎn)(同源性為98.2%)。結(jié)論本研究為山羊流產(chǎn)嗜衣原體的最新流行病學(xué)動(dòng)態(tài)奠定了基礎(chǔ)。
關(guān)鍵詞:流產(chǎn)嗜衣原體;鑒定;分子特征分析
Supported by the National Natural Science Foundation of China(No. 31201914), the China Post Doctoral Science Foundation(No. 2013M530683), and the China Agriculture Research System(No. CARS-39)
羊流產(chǎn)衣原體病又稱為母羊地方性流產(chǎn),是流產(chǎn)嗜衣原體(Chlamydophilaabortus,C.abortus)引起的一種接觸性人獸共患傳染病[1-2]。衣原體科分為衣原體屬(Chlamydia)和嗜衣原體屬(Chlamydophila),流產(chǎn)嗜衣原體曾經(jīng)被稱為鸚鵡熱衣原體血清1型,是引起山羊和綿羊繁殖障礙的重要原因[3-4]。本病在許多國家和地區(qū)均有發(fā)生[5-6],母羊感染流產(chǎn)衣原體后一般表現(xiàn)為隱性感染,直到發(fā)生妊娠后出現(xiàn)流產(chǎn)、早產(chǎn)、死產(chǎn)或產(chǎn)弱羔,新生羔羊發(fā)生腦炎、關(guān)節(jié)炎,種公羊發(fā)生睪丸炎、附睪炎[7]。女性感染本病主要表現(xiàn)是盆腔炎[8],孕婦感染后可造成流產(chǎn)、早產(chǎn)、死產(chǎn),嚴(yán)重者可發(fā)生膿毒敗血癥,對(duì)孕婦的生命安全有嚴(yán)重威脅[9-10]。
由于本病與布病等疾病臨床癥狀的相似性,且感染后有較長的潛伏期[11],所以僅靠臨床癥狀觀察,病理剖檢等常規(guī)方法確診還有一定困難,需配合一些實(shí)驗(yàn)室診斷方法才能確診。目前,衣原體病的實(shí)驗(yàn)室診斷通常采用染色和鏡檢、補(bǔ)體結(jié)合試驗(yàn)、間接血凝試驗(yàn)、ELISA、PCR擴(kuò)增等,其中PCR檢測(cè)因其快速靈敏而被廣泛使用[12-13]。ompA基因是衣原體的主要外膜蛋白基因,常用于衣原體的鑒定和進(jìn)化分析[14-15]。本文從廣東某羊場(chǎng)的疑似病例中采取病料并進(jìn)行了病理切片染色、ompA基因的擴(kuò)增以及基于ompA基因的遺傳進(jìn)化分析。
1材料與方法
1.1材料病料取自廣東某羊場(chǎng)疑似衣原體感染的流產(chǎn)母羊的羊水、胎兒胎衣等。
1.2方法
1.2.1現(xiàn)場(chǎng)病理剖檢現(xiàn)場(chǎng)觀察流產(chǎn)母羊胎盤、子宮等的病變情況,流產(chǎn)胎兒的皮膚、黏膜等的病變情況
1.2.2病理切片吉姆薩染色將采集的患病羊的羊水進(jìn)行直接涂片,用甲醇固定3 min,吉姆薩染色液染色30 min后,用純化水洗脫。晾干后置于顯微鏡下觀察。
引物設(shè)計(jì) 根據(jù)GenBank上C.abortusompA基因序列設(shè)計(jì)ompA基因特異性擴(kuò)增引物,上游引物:5′-ATGAAAAAACTCTTGAAATCG-3′,下游引物:5′-TTAGAATCTGAATTGAGCA。引物由上海生工有限公司合成。
1.2.3ompA基因擴(kuò)增用DNA提取試劑盒從病料中提取DNA,用上述引物進(jìn)行PCR擴(kuò)增。反應(yīng)體系為DNA聚合酶(5 U/μL)0.25 μL,10×buffer 5μL,dNTP mixture 4 μL,上下游引物(20 μmol/μL)各1 μL,ddH2O 33.75 μL。反應(yīng)條件:95 ℃ 預(yù)變性 5 min ;94 ℃變性 50 s,52 ℃退火 50 s,72 ℃ 延伸 1 min , 35 個(gè)循環(huán)后, 72℃延伸10 min。反應(yīng)結(jié)束后取 5 μL 擴(kuò)增產(chǎn)物進(jìn)行瓊脂糖凝膠電泳,檢測(cè)擴(kuò)增結(jié)果。
1.2.4序列測(cè)定及分析經(jīng)電泳檢測(cè)片段大小合適的擴(kuò)增產(chǎn)物附上下游引物送出測(cè)序。利用MEGA軟件將測(cè)序確證的ompA基因序列與GenBank中已公布的其他菌株ompA序列進(jìn)行比對(duì),并進(jìn)行基因序列同源性分析和遺傳進(jìn)化關(guān)系分析。
2結(jié)果
2.1剖檢變化對(duì)發(fā)病羊進(jìn)行剖檢,可見病羊胎衣不下,子宮內(nèi)膜出血、壞死,胎兒全身水腫等羊流產(chǎn)嗜衣原體感染的典型癥狀(圖1)。
A:胎衣不下; B:胎兒全身水腫;C:子宮內(nèi)膜出血壞死
2.2羊水吉姆薩染色將采集的流產(chǎn)母羊的羊水涂片、固定、染色后,顯微鏡下可觀察到圓形或橢圓形的包涵體(圖2)。
→示意包涵體
2.3ompA基因擴(kuò)增用上述特異性引物進(jìn)行PCR擴(kuò)增,結(jié)束后進(jìn)行瓊脂糖凝膠電泳,得到大小約為1 200 bp的片段,符合預(yù)期結(jié)果(圖3)。
2.4序列測(cè)定及分析 序列測(cè)定結(jié)果顯示ompA基因全長1 170 bp,GC含量為44.36%,編碼390個(gè)氨基酸。將該基因序列提交GenBank獲得序列號(hào)KP984478。將該序列和已經(jīng)公布的ompA序列用MEGA軟件進(jìn)行比對(duì)分析并構(gòu)建系統(tǒng)進(jìn)化樹(從1~1 058 bp),結(jié)果表明本次測(cè)定的流產(chǎn)嗜衣原體與已公布的流產(chǎn)嗜衣原體ompA基因序列同源性為98.2%~99.1%,與AJ004873同源性最低,與KF130872同源性最高(圖2)。對(duì)17個(gè)NCBI的編號(hào)進(jìn)行列表,并標(biāo)注相關(guān)信息(表1)。
圖3 羊流產(chǎn)衣原體ompA基因擴(kuò)增
GenBankHostStrainYearM73036L39020AJ005618KF130872EF202609AJ005615AJ005613AJ005617AJ004875AJ004874DQ227703DQ471955AF272945AJ440239AJ004873EU086705DQ478954OvisariesBostauruSusscrofaGoatPigSusscrofaSusscrofaSusscrofaSusscrofaSusscrofa———SheepCapraaegagrus——————Swine———B577BA1pmSH1———cp/12pmd623pm112pm225pm326pm234———TWC+3/95-HLLGOCLH196OCLH196B11011———19931995200020132006199819981998199819982005200620002002200220072006
注:“——”表示無相關(guān)信息。
Note:“——”Denotes no information.
3討論
肉羊的集約化、規(guī)?;l(fā)展是養(yǎng)羊業(yè)的一大趨勢(shì),但傳染病帶來的危害也更為嚴(yán)重。羊流產(chǎn)嗜衣原體感染引起的羊地方性流產(chǎn)主要通過呼吸道或消化道傳播,是導(dǎo)致羊繁殖障礙的主要原因之一,嚴(yán)重影響著養(yǎng)羊業(yè)的發(fā)展和相關(guān)從業(yè)人員的身體健康,近年來已逐漸引起關(guān)注[16-17]。前期研究表明,我國多個(gè)省份的羊衣原體感染率普遍較高,其中甘肅90.00%,寧夏67.74%,湖北60.00%,山東52.75%,吉林51.91%,并且不同年份的感染率呈上升趨勢(shì)[18]。
圖4 廣東分離株ompA基因遺傳進(jìn)化分析
疾病的快速診斷及分子特征分析可以了解疫病的分布規(guī)律,掌握本地的疫病流行情況以及流行株,從而針對(duì)性的制定方案預(yù)防疾病的發(fā)生,對(duì)于流行病學(xué)研究及疫病防控具有重要意義[19]。PCR檢測(cè)由于快速、靈敏、簡便等優(yōu)點(diǎn)在衣原體病的診斷中得到廣泛應(yīng)用。ompA基因編碼40 kDa的衣原體主要外膜蛋白,主要起到離子通道的作用,參與能量轉(zhuǎn)換[4,20-21]。羊流產(chǎn)衣原體病的分子生物學(xué)診斷中大多采用以ompA基因?yàn)閷?duì)象。
為確診該羊場(chǎng)的疑似衣原體感染病例,作者進(jìn)行了衣原體病原學(xué)檢測(cè),從切片中觀察到圓形或橢圓形的包涵體,PCR擴(kuò)增出流產(chǎn)嗜衣原體的ompA基因。結(jié)合臨床癥狀將疑似病例確診為流產(chǎn)嗜衣原體感染。遺傳進(jìn)化分析表明本次分離鑒定的流產(chǎn)嗜衣原體菌株與2013年公布的中國貴州分離株KF130872遺傳關(guān)系最近,屬于同一進(jìn)化分支。目前關(guān)于流產(chǎn)嗜衣原體的分子流行病學(xué)研究還較少,本次測(cè)定并提交的ompA基因序列為該病原的分子流行病學(xué)研究積累了資料,對(duì)于了解我國目前羊流產(chǎn)嗜衣原體的分子流行病學(xué)特點(diǎn)具有重要意義。
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DOI:10.3969/j.issn.1002-2694.2016.01.004
通訊作者:張克山, Email:zks009@126.com
中圖分類號(hào):R374
文獻(xiàn)標(biāo)識(shí)碼:A
文章編號(hào):1002-2694(2016)01-0017-04
Corresponding author:Zhang Ke-shan, Email:zks009@126.com
收稿日期:2015-07-13;修回日期:2015-11-17
Identification and molecular characteristic of Chlamydophila abortus Guangdong strain in goats
WANG Ling-ling,LIU Yong-jie,ZHENG Hai-xue,ZHANG Ke-shan,LIU Xiang-tao
(LanzhouVeterinaryResearchInstituteofChineseAcademyofAgricultureScience,StateKeyLaboratoryofVeterinaryEtiologicalBiology,NationalFoot-and-MouthDiseaseReferenceLaboratory,Lanzhou730046,China)
Abstract:To identify suspected goats enzootic abortion cases and analyze the molecular characteristic of the pathogen, tissue samples were collected and detected by pathology examination, GIMSA dying assay, microscopic examination, specific gene amplification and sequencing, and the phylogenic tree based on gene ompA was performed. Results showed that the pathologic changes were similar with Chlamydophila abortus (C. abortus) infection, the typical characters of Chlamydia infection were observed by microscope after GIMSA dying and specific gene ompA was amplified by PCR, indicating the disease was caused by C. abortus. Gene ompA sequence was submitted to GenBank and obtained accession number KP984478. Phylogenetic tree analysis revealed that the C. abortus strain identified had a closest genetic relationship with KF130872 isolated from Guizhou in 2013(with 99.1% homology), and had the farthest relationship with AJ004873 published in 2002(with 98.2% homology). Results of this paper laid the foundation for epidemiologic further study on C. abortus.
Keywords:Chlamydophila abortus; identification; molecular characteristic analysis
國家自然科學(xué)基金(NSFC-31201914),中國博士后科學(xué)基金(2013M530683), 國家現(xiàn)代肉羊產(chǎn)業(yè)技術(shù)體系(CARS-39)聯(lián)合資助