淡水鱼类常见寄生虫病综合防治技术

<正>一、淡水鱼类寄生虫病的发病规律淡水鱼类寄生虫病可分为两大类,一是单细胞原生动物寄生虫;二是多细胞后生大型寄生虫。1、单细胞原生动物寄生虫病(1)粘孢子虫病。其中碘泡虫病危害较广,碘泡虫形成的胞囊,大的肉眼可见。鲢碘泡虫主要为害白鲢的中枢神经系统和感觉器官、体表、鳃、心脏、血液等,致使病鱼狂游乱窜,打圈,狂跳出水面,鱼体极度消瘦,尾上翘,肝、脾萎缩,腹腔积水,肠内无食物等症状。饼形碘泡虫主要寄生于草鱼     

论淡水鱼类寄生虫病防治

<正>1淡水鱼类寄生虫病的发病规律淡水鱼类寄生虫病可分为两大类,一是单细胞原生动物寄生虫;二是多细胞后生大型寄生虫。1.1单细胞原生动物寄生虫病(1)粘孢子虫病。其中碘泡虫病危害较广,碘泡虫形成的胞囊,大的肉眼可见。鲢碘泡虫主要为害白鲢的中枢神经系统和感觉器官、体表、鳃、心脏、血液等,致使病鱼狂游乱窜,打圈,狂跳出水面,鱼体极度消瘦,尾上翘,肝、脾萎缩,腹腔积水,肠内无食物等症状。饼形碘泡虫主要寄生于草鱼种的     

双斑东方鲀海盘虫病病原鉴定和鳃组织病理观察

海盘虫Haliotrema sp.病是双斑东方鲀Takifugu bimaculatus养殖生产上主要致死性病害之一，为深入了解该病，本研究中从2016年6月—2019年6月对池塘养殖的双斑东方鲀海盘虫病发病情况进行调查，利用形态学观察、几丁质结构特征分析和分子生物学技术对病原虫体进行鉴定与分析，并观察病鱼鳃组织病理变化。结果表明：该病春末夏初和秋季易发，发病时病鱼主要症状为缓游于水面，食欲减退或不摄食；体色苍白，体形消瘦，尾鳍、臀鳍缺损，鳃丝上有大量海盘虫虫体，鳃片黏液多，肝脏、脾脏充血；病原虫体经形态学观察和几丁质结构特征分析，鉴定为双裂海盘虫H.bilobatus,双斑东方鲀为其宿主新记录；对该虫体18S rDNA和28S rDNA(C1～D2区)基因片段扩增测序分析显示，其18S rDNA序列(1 282 bp)与栉齿刺尾鲷海盘虫H.ctenochaeti、丝蝴蝶鱼海盘虫H.aurigae等序列相似，一致性达97.68%～98.30%,其28S rDNA序列(886 bp)(C1～D2区)与镰茎海盘虫H.sicklocirrus序列最相似，但一致性仅达90.28%;基于18S rDNA和28S rDNA序列构建的系统发育树均显示，双裂海盘虫单为独立分支，为NCBI基因数据库未登记海盘虫属虫种；鳃组织病理学观察发现，虫体寄生导致双斑东方鲀鳃丝机械损伤、鳃上皮组织增生或脱落，甚至引起鳃组织病变、出血，重度感染会引发鳃小片坏死、崩解，大量黏液浸润鳃丝，从而使病鱼呼吸困难而死亡。研究表明，双裂海盘虫为福建池塘养殖双斑东方鲀海盘虫病的感染病原，该病春末夏初和秋季易流行。     

大泷六线鱼链球菌病的病原及其防治

2008年9月,辽宁省某养殖场养殖的大泷六线鱼Hexagrammos otakii暴发链球菌病,患病鱼鳃盖内侧发红,体表无明显症状。对病鱼进行细菌分离,从脑部分离出纯度较高的细菌,并经人工感染试验确定了该菌的致病性。对该细菌进行形态观察、生理生化特征比较及16S rRNA分子鉴定,测定了16S rRNA基因序列,并构建系统发育树。结果表明,该致病菌(ZG0990)与海豚链球菌Streptococcus iniae的相似性最高(99.48%)。药敏试验表明,该致病菌对青霉素G、先锋Ⅴ和呋喃妥因等多种药物敏感,并且将青霉素G按质量分数为0.1%的量拌饲投喂病鱼,取得了良好的治疗效果。     

泡球蚴福尔马林固定标本的分子生物学鉴定方法

目的用分子生物学的方法对福尔马林固定液中浸泡的泡球蚴标本进行鉴别诊断。方法从感染了多房棘球绦虫的大鼠体内提取泡球蚴病理组织,用福尔马林固定液分别浸泡6个月和12个月,将经浸泡后的组织提取DNA,用多房棘球绦虫的特异性引物Em H15/17进行扩增,与多房棘球绦虫的线粒体12S RNA序列对比,从而进行虫种鉴定。结果在扩增的43例样本中,福尔马林固定液中浸泡6个月和12个月的泡球蚴组织分别有25例和18例,经PCR扩增后比对,发现均与多房棘球绦虫具有相同的序列。结论用这种分子生物学的方法,可以使保存于福尔马林固定液中鼠来源的泡球蚴标本得到较满意的鉴定。预示这种方法对于人体来源的泡球蚴福尔马林固定标本的分子鉴定工作具有可行性。     

鲶源维氏气单胞菌的分离鉴定及药敏特性

为探明发病怀头鲶Silurus soldatovi的病原及其生物学特征,从发病怀头鲶体内分离出1株革兰氏阴性细菌SG-1,通过细菌形态学观察、理化特性、16S r DNA测序和构建系统发育进化树分析对其进行了鉴定。结果表明:分离菌SG-1菌株葡萄糖产气、氧化酶、硝酸盐还原为阳性,鸟氨酸脱羧酶、硫化氢为阴性;进一步采用PCR方法扩增其16S r DNA序列,测序获得片段大小为1409 bp,与维氏气单胞菌Aeromonas veronii模式菌株ATCC35624序列相似性达99.86%;构建系统发育树分析显示,分离菌与维氏气单胞菌自然聚为一支,最终判定SG-1菌株为维氏气单胞菌;人工感染斑马鱼Danio rerio、鲶S.soldatovi,其死亡率均达100%,病鱼呈现体表出血、肛门红肿、腹水等症状;药敏试验结果显示,该菌对头孢克肟、头孢哌酮、头孢噻肟、诺氟沙星、左氟沙星、恩诺沙星、氟苯尼考等药物敏感,对阿莫西林、氨苄西林、磺胺异恶唑、甲氧嘧啶、复方新诺明等耐药。本研究结果为了解维氏气单胞菌感染鲶的致病机理及其该病的预防治疗提供了科学参考。     

鲶源维氏气单胞菌的分离鉴定及药敏特性

为探明发病怀头鲶Silurus soldatovi的病原及其生物学特征,从发病怀头鲶体内分离出1株革兰氏阴性细菌SG-1,通过细菌形态学观察、理化特性、16S r DNA测序和构建系统发育进化树分析对其进行了鉴定。结果表明:分离菌SG-1菌株葡萄糖产气、氧化酶、硝酸盐还原为阳性,鸟氨酸脱羧酶、硫化氢为阴性;进一步采用PCR方法扩增其16S r DNA序列,测序获得片段大小为1409 bp,与维氏气单胞菌Aeromonas veronii模式菌株ATCC35624序列相似性达99.86%;构建系统发育树分析显示,分离菌与维氏气单胞菌自然聚为一支,最终判定SG-1菌株为维氏气单胞菌;人工感染斑马鱼Danio rerio、鲶S.soldatovi,其死亡率均达100%,病鱼呈现体表出血、肛门红肿、腹水等症状;药敏试验结果显示,该菌对头孢克肟、头孢哌酮、头孢噻肟、诺氟沙星、左氟沙星、恩诺沙星、氟苯尼考等药物敏感,对阿莫西林、氨苄西林、磺胺异恶唑、甲氧嘧啶、复方新诺明等耐药。本研究结果为了解维氏气单胞菌感染鲶的致病机理及其该病的预防治疗提供了科学参考。     

含HSV-TK基因及IL-18基因复制缺陷型腺病毒载体的构建和鉴定

目的:分别构建含TK及IL-18基因的重组腺病毒载体,并进行鉴定。方法:通过DNA重组技术,构建含有目的基因的复制缺陷型腺病毒Ad CMV-TK及Ad CMV-IL-18;将上述重组腺病毒液感染293细胞,提取DNA,进行PCR鉴定;将病毒液感染293细胞,扩增病毒,用OD260法测定病毒滴度。结果:经PCR鉴定,鉴定正确的腺病毒命名为Ad CMV-TK及Ad CMV-IL-18,测定病毒滴度Ad CMV-TK=1.28×109 PFU/m L;Ad CMV-IL-18=1.28×109 PFU/m L。结论:成功构建了含HSV-TK基因及IL-18基因重组腺病毒载体,为肿瘤的基因治疗提供了理论依据及实验数据。     

论泥鳅病害的综合防治方法

<正>1寄生虫病1.1杯体虫病病鳅漂浮水面,游动吃力,状似缺氧浮头。鱼体发黑,仔细观察可见其鳃盖后缘略发红,鳍条残损。刺激鳃丝黏液分泌增加,鳃丝水肿充血,血窦数量明显增加,大量虫体寄生时,病鱼离群独游,不摄食,呼吸频率加快。该病是由杯体虫附着在泥鳅的皮肤、鳃上引起的寄生虫病。全国各养鳅地区都有发生,若大量寄生在体长1.5-2cm的鳅苗上,会造成鳅苗呼吸困难,严重时导致寄主死亡。该病一年四季均会发生,以5-8月较为普遍。     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

在市场中实践在实践中学习在学习中进步--工程公司市场化进程的回顾与展望

近两年来，工程公司在提高市场竞争意识、推动市场化进程中做了大量工作，其中坚持走出去的方针是我们自我加压、推行加快市场化步伐的一个重要战略步骤。     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

新形势下高校强化基建财务管理的探讨

在市场条件下高校基建财务人员在加强日常财务管理的同时,必须树立起高度的工作责任心,抓好事前监督、事中监督、事后监督三个环节,全面理解、贯彻执行《高等学校财务制度》,管好用好各项基本建设资金,提高基建财务管理水平,更好地完成高校各项基建任务,以有限的投资,最快的建设速度,获得最大的投资效益。     

2005年北京办公物业市场七大趋势

趋势一:CBD区域写字楼集中放量从各区域规划方案上看,CBD区域多数项目在03～04年处于项目的报批手续及拆阶段,预计2005年正式推向市场,因此2005年CBD区域将成为北京市场供应集中的域,区域即将供应的项目有北京财富中心(二期)、金地国际花园、万达广场、SOHO尚都、万通中心、世纪财富中心、怡禾国际中心、光华国际等。除去未知项目,2005CBD写字楼办公面积的供应量为60万平方米左右。中关村区域经过一段时间的集中供后开始逐步放缓,2005年供应的体量相对较大的项目有中关村金融中心、新中关。金街区域可能开盘的项目只有2个:英蓝国际中…     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

Variation in property taxation in Tulsa

Conclusions It may be reasonably concluded from this study that the range of variation in these ratios of assessed to actual value are of a reasonable size for the great majority of cases. The frequency distribution of these sample ratios was not normal, however, as was assumed a process of this type would produce. On the other hand, the failure of the regression analysis to identify any significant variables which would explain these variations would tend to re-enforce the assumption that the fluctuations were indeed of a random nature.To sum it up in one paragraph, aside from a few extreme cases, the assessing process appears to give estimates which are more consistent than would be expected under the assumption that any errors would be of a random nature, but the regression analysis was unable to isolate any particular socioeconomic characteristics which would explain the variation which was present.Financial support for this research project was furnished by the University of Tulsa.