福寿螺休眠期体内广州管圆线虫生长发育及其感染性的观察研究

目的 了解福寿螺处于休眠期对其体内感染的广州管圆线虫幼虫生长发育及其感染性的影响。 方法 来自实验室的广州管圆线虫L1幼虫感染福寿螺，感染后第1 天螺置于25.0～25.5 ℃ 恒温室中休眠，观察体内幼虫生长发育情况，第13天起解剖观察幼虫生长发育情况。感染后第20 天福寿螺置冬季室内自然变温条件下休眠2个月，每隔10 d观察螺体内幼虫活力。检获的L3幼虫经口或腹腔注射感染SD大鼠，观察其感染性。同时观察螺的生存与体重变化情况，并以水族缸饲养螺作平行对照。 结果 25.0～25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育，且其幼虫发育历期为（16.3±0.6） d，显著快于水族缸饲养螺（17.6±0.96）d（t=5.72，P<0.01）。冬季室内自然变温条件下的休眠螺，生存率高于水族缸饲养螺（P<0.05),体重下降率为（33.5±4.3）%, 也高于水族缸饲养螺[（9.0±2.3）%, t=10.68， P<0.01]。但随着休眠期的延长其死亡率增高（x²=18.31，P<0.01）。从存活螺体内检获的不同活力的L3幼虫均可感染SD大鼠。 结论 25.0～25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育，冬季室内自然变温条件下螺休眠或水族缸饲养，其体内幼虫均具有感染性。 感染的福寿螺越冬方式，休眠明显优于水族缸饲养。     

广东省首次广州管圆线虫感染局部暴发的流行病学调查

目的了解一起外来民工集体感染广州管圆线虫疫情的流行因素。方法对广宁县文坑村疑似广州管圆线虫感染的云南白族民工、其他民工和当地居民进行现场流行病学调查;采集疑似病人和部分民工血清检测广州管圆线虫抗体;在疫点及周围捕捉老鼠,采集福寿螺、东风螺和新鲜鼠粪进行病原学检查。结果2007年3月24日17名云南白族民工共同进食在居住地附近的田地里采集的福寿螺,其中先后有6人发病,罹患率为35.29%(6/17),全部患者均进食过生螺肉。仅捕获黄胸鼠1只,未发现广州管圆线虫感染;采集新鲜鼠粪8份,其广州管圆线虫感染率为75%(6/8)。检查福寿螺189只,平均感染率为2.12%(4/189),感染度为平均每只螺含37条广州管圆线虫幼虫,其中大福寿螺的感染率较高,为21.43%(3/14);未采集到东风螺。采集5份患者和2份无症状民工的血清,其中2份患者血清的广州管圆线虫抗体呈弱阳性。结论广宁县横山镇文坑村是广州管圆线虫病的重要自然疫源地。外来民工同吃生福寿螺是引起广州管圆线虫感染局部暴发的主要因素。     

广州及其周边地区福寿螺体内广州管圆线虫感染的现状调查

目的了解广州及其周边地区福寿螺感染广州管圆线虫的情况，为防治提供依据。方法．人式消化174只福寿螺。显微镜下检查消化液中有无广州管圆线虫幼虫。结果广东省广州市花都区、广州市越秀区、兴宁、化州、蕉岭、茂名等六地的福寿螺感染率分别为25．0％、23．1％、24．2％、18．5％、14．3％、13．3％，广东省东莞采集的福寿螺未发现感染广州管圆线虫。结论广东省广州市花都区、广州市越秀区、兴宁、化州、蕉岭、茂名等六地存在广州管圆线虫的自然疫源地。     

湖南省抽样点广州管圆线虫宿主分布及其感染情况调查

目的了解湖南地区广州管圆线虫宿主及疫源地的分布。方法从野外、餐饮店、农贸市场等场所采集食用淡水螺、陆生螺、蛞蝓、虾、溪蟹、鱼和青蛙,用组织捣碎匀浆法及过筛沉淀法检查中间宿主、转续宿主体内的广州管圆线虫幼虫;解剖检查野鼠心肺广州管圆线虫成虫。结果7县(市、区)有5县(市、区)从野外捕获到福寿螺;3县从野外捕获中国圆田螺、中华圆田螺、方形环棱螺和蛞蝓,检查均未发现广州管圆线虫幼虫;7县(市、区)均未发现褐云玛瑙螺。6县(市)解剖褐家鼠、黄胸鼠、鼩鼱3种鼠,仅在1只褐家鼠的心脏和肺检获广州管圆线虫成虫8条。结论福寿螺在湖南南部地区分布广泛,首次证实湖南存在广州管圆线虫疫源地。     

用多重PCR技术检测小管福寿螺体内广州管圆线虫幼虫

目的建立一种多重PCR方法检测小管福寿螺体内的广州管圆线虫幼虫。方法根据广州管圆线虫核糖体小亚基rDNA基因序列(GenBank登录号为AY295804)设计特异性引物,并与小管福寿螺16srDNA的特异性引物组合,建立多重PCR检测方法。分别以阳性和阴性小管福寿螺DNA为模板进行多重PCR扩增,电泳鉴定并测序。用阴性小管福寿螺DNA倍比稀释200条广州管圆线虫Ⅲ期幼虫DNA模板,使之浓度分别为1200ng/μl、120ng/μl、12ng/μl、1200pg/μl、120pg/μl和12pg/μl,检测该方法的敏感性。野外采集小管福寿螺172只,肺检法检测后,进行多重PCR扩增,计算敏感性和特异性。结果电泳和测序结果证实该多重PCR检测方法能有效扩增出目的片段,小管福寿螺和广州管圆线虫的目的片段分别为550和405bp。该方法可检测出广州管圆线虫Ⅲ期幼虫DNA的最小浓度为120pg/μl。肺检法和多重PCR法检测均为阳性结果的45只,两法均为阴性的100只。肺检法为阴性、多重PCR法为阳性的24只,肺检法为阳性而多重PCR法检测为阴性的3只。多重PCR的敏感性和特异性分别为93.8%(45/48)和80.6%(100/124)。多重PCR法的阳性检出率为40.1%(69/172),肺检法阳性检出率为27.9%(48/172),差异具有统计学意义(χ2=14.8,P0.01)。结论建立了检测小管福寿螺体内广州管圆线虫的多重PCR方法。     

Bioaccumulation and toxicity of copper in outdoor freshwater microcosms

This study characterizes the effects of copper (Cu) on Florida apple snails (Pomacea paludosa) and mosquito fish (Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m³ fiberglass microcosm tanks. Introducing juvenile apple snails (≤7 d old) and mosquito fish (2-3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 μg/L, respectively and decreased to low saturation levels of about ≤9 μg/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model (L_∞) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g. Growth rate (k) of the snails increased in order of shell height (0.459), shell length (0.550), and shell weight (0.598). There was no reproduction in the snails in any treatments including the reference during the exposure phase. However, Cu did not affect reproduction of fish during this period. Copper concentrations in periphyton from Equus, SRB, and AGLR microcosms ranged from 2 to 62, 31 to 371, and 13 to 478 mg/kg, respectively. Copper concentrations in fish at the beginning, days 30 and 150 of the study ranged from 3.19 to 7.53 mg/kg and were not significantly different from the different treatments. Average Cu concentrations in the soft tissue of dead snails from SRB and AGLR microcosms were 4602 mg/kg dw (ranged from 2913 to 8370 mg/kg dw) and 2824 mg/kg dw (ranged from 2118 to 3600 mg/kg dw), respectively. The Cu concentrations in the soft tissue of dead snails found in this study were higher than the tissue Cu concentrations in live aquatic organisms reported in the literature. These high Cu concentrations in edible apple snail soft tissue might pose a risk to Florida apple snail predators, including the snail kite. The post-exposure phase, with snails exposed to only water (i.e., no soils) showed depuration of copper from apple snails and reproduction in all treatments.     

基于线粒体COⅠ基因的广西不同地区福寿螺遗传多态性分析

目的 通过对广西不同地区福寿螺的COⅠ基因进行分析,以了解广西福寿螺种群的遗传多态性。方法 从南宁市横县、桂林市全州县和荔浦县、贺州市富川县、百色市田林县和崇左市凭祥县共计6个县区采集福寿螺样本,提取DNA并进行COⅠ基因的PCR扩增及测序。运用MAGE 7.0将本研究获得的单倍型与GenBank中的福寿螺单倍型使用邻接法构建系统进化树,并计算个体间的遗传距离,分析其遗传多样性。结果 COⅠ基因长度为493 bp,从11个样本鉴定出2种单倍型：单倍型1（Haplotype 1）和单倍型2（Haplotype 2）。其中9个样本为Haplotype 1,分别来源于南宁市横县（2个）、贺州市富川县（1个）、桂林市荔浦县（1个）、百色市田林县（2个）、崇左市凭祥县（3个）,该单倍型与小管福寿螺遗传距离最近,为0.047;2个样本为Haplotype 2,分别源自为南宁市横县和桂林市全州,与孤岛福寿螺遗传距离最近,为0.062。根据上述条件所构建的进化树形成了7个分支,分别为P. canaliculata、P. camena、P. insularum、P. paludosa、P. diffusa、P. haustrum、和外群Pilaconica。Haplotype 1与来自美国夏威夷 （GenBank登录号 EU 523129）的P. canaliculata组成一个分支,Haplotype 2与来自巴西（GenBank登录号EF514942）的P. insularum组成一个分支,且置信值均在98%以上。结论 初步判断广西地区存在小管福寿螺与孤岛福寿螺两种类型的福寿螺,其种群内没有发现遗传分化。     

Metal Contamination in the Sediment, Pondweed, and Snails of a Stream Receiving Effluent from a Lead/Zinc Mine in Southern China

This study assessed the potential of Potamogeton crispus and Pomacea canaliculata as biomonitors of sedimentary metal contamination. The results indicate P. crispus possesses several attributes of a biomonitor and its tissue concentrations of Cd, Pb and Zn may reflect the levels of sedimentary contamination by these metals. Although P. canaliculata can accumulate metals to high levels and serve as an indicator of metal contamination, its tissue metal concentrations did not correlate with those of the sediments or macrophytes.     

广州管圆线虫生活史动物模型的效果观察

目的 目的 观察人工建立广州管圆线虫生活史动物模型的效果, 为进一步开展广州管圆线虫病研究提供基础资 料。 方法 方法 从人工感染广州管圆线虫的福寿螺中分离出3期幼虫, 经灌胃感染SD大鼠。感染后第6周从大鼠粪便中分 离、 计数广州管圆线虫1期幼虫, 并将大鼠每天排出的1期幼虫人工感染健康福寿螺。3周后, 用胃蛋白酶消化法, 从福 寿螺内分离出广州管圆线虫3期幼虫。 结果 结果 SD大鼠感染广州管圆线虫3期幼虫后第6周, 其粪便中均检出1期幼虫, 并成功感染健康福寿螺得到3期幼虫。 结论 结论 在实验室条件下以每只大鼠50条广州管圆线虫3期幼虫的感染量可成功 建立广州管圆线虫生活史动物模型及其实验室种群。     

广州及其周边地区福寿螺体内广州管圆线虫感染的现状调查

目的了解广州及其周边地区福寿螺感染广州管圆线虫的情况,为防治提供依据。方法．人式消化174只福寿螺。显微镜下检查消化液中有无广州管圆线虫幼虫。结果广东省广州市花都区、广州市越秀区、兴宁、化州、蕉岭、茂名等六地的福寿螺感染率分别为25．0％、23．1％、24．2％、18．5％、14．3％、13．3％,广东省东莞采集的福寿螺未发现感染广州管圆线虫。结论广东省广州市花都区、广州市越秀区、兴宁、化州、蕉岭、茂名等六地存在广州管圆线虫的自然疫源地。