环烷酸铜对离体小瓜虫杀灭效果的研究

采用0.05、0.1、0.2、0.4、0.8mg/L 5个浓度梯度的环烷酸铜溶液对小瓜虫成虫、幼虫以及孢囊进行离体杀灭试验,结果表明:0.1~0.2mg/L环烷酸铜溶液对小瓜虫幼虫及成虫都有较强杀灭作用,0.4~0.8 mg/L环烷酸铜能控制小瓜虫包囊分裂。     

肉桂活性成分肉桂醛杀灭离体多子小瓜虫效果

研究从肉桂中分离纯化出具有抑杀多子小瓜虫活性的化合物。以乙醇为提取剂,用索氏超声提取法从肉桂中提取浸膏,再用石油醚、乙酸乙酯、甲醇为萃取剂,萃取不同有效组分,以不同浓度分别进行杀灭离体多子小瓜虫实验,发现石油醚萃取物的杀虫效果最优。然后对石油醚萃取物采用硅胶层析柱和制备型高效液相色谱进行分离纯化,利用质谱和核磁波谱分析,最终鉴定其杀虫活性成分为肉桂醛;将肉桂醛溶于二甲基亚砜并用二倍梯度稀释法配成不同浓度的药液测试其对离体小瓜虫的杀灭活性。结果表明,100%杀灭滋养体和感染性幼虫的剂量分别为50和8 mg/L,半数有效浓度分别为13.9和1.8 mg/L;使用剂量在50 mg/L可完全抑制小瓜虫包囊孵化。     

20种中草药杀灭离体小瓜虫的药效研究

选用20种不同中草药,研究其不同浓度的水提物对多子小瓜虫(Ichthyophthirius multifiliis)成虫、包囊和幼虫的离体杀灭实验效果。结果显示:0.1 g/L槟榔和乌梅对各个阶段的虫体均有杀灭效果,0.1 g/L大黄和黄芩1 h内对幼虫有杀灭效果,1.0 g/L浓度能杀灭成虫和包囊,表明槟榔、乌梅、大黄、黄芩的杀虫效果相对较好;贯众、乌药、枳壳等13种中药浓度达到10 g/L、50 g/L或100 g/L才具有一定杀虫作用,但效果不很显著;熟地黄、茯苓和黄芪即使浓度达到100 g/L时,也不能杀灭虫体。     

青蒿末水浸提液对多子小瓜虫杀灭效果的研究

采用0.05、0.1、0.5、1.0以及5.0 g/L 5个浓度梯度的青蒿末水浸提液对多子小瓜虫成虫、幼虫及孢囊进行离体杀灭试验。结果表明:0.5 g/L以上浓度的青蒿末水浸提液可完全杀灭多子小瓜虫的幼虫,0.1～1.0 g/L浓度可部分杀灭成虫,1.0 g/L浓度可部分抑制孢囊分裂,5.0 g/L浓度可完全杀灭成虫和孢囊。     

青蒿素对小瓜虫病治疗作用初探

小瓜虫病是由小瓜虫感染各种淡水鱼类引起的疾病，此病最明显的症状就是鱼体表形成白点，所以生产上又称“白点”病。以前国内治疗小瓜虫病常采用硝酸亚汞、孔雀石绿、福尔马林等药物，但由于这些药物有致癌、致突变性、毒性大的缺点，而且低毒药物对小瓜虫胞囊和寄生在鱼身上的虫体的杀灭作用不明显，冈此，筛选高效、低毒、低残留的无公害药物迫在眉睫。本文就青蒿素对小瓜虫病的治疗效果做了初步研究。     

槟榔防治小瓜虫病初报

多子小瓜虫为纤毛虫纲,膜口亚目,凹口科,小瓜虫属。其幼虫钻入鱼体表上皮层或鳃组织间刺激周围的上皮细胞增生,剥食吸收上皮细胞及血球营养造成寄主烦躁不安最后死亡。由于其特殊生物学特性,容易形成胞囊,能抵御外界不利环境及一般药物作用,所以难以找到理想的药物进行治疗。治     

生姜、辣椒治疗小瓜虫病的效用试验

小瓜虫,隶属寡膜纲,膜口亚纲,膜口目。凹口科,小瓜虫属,是鱼类的主要寄生虫之一,常寄生在鱼类的皮肤、鳍、鳃、头、口腔及眼等处,形成胞囊呈白色小点状,肉眼可见,俗称白点病。感染小瓜虫后鱼体焦躁不安,摄食减少,寄生部位充血、发炎,组织增生,特别是鳃部寄生将影响呼吸,造成大批鱼死亡,死亡率可达60％～70％,给养殖生产带来严重损失。至于治疗此病的药物,虽然报道的不少,如硝酸亚汞、醋酸亚汞、孔雀石绿、福尔马林、硫酸铜等,     

欧洲鳗的小瓜虫病及其防治

欧洲鳗小瓜虫病流行广,对苗种的危害尤为严重。水温、水质以及药物的使用对小瓜虫表一定影响。绿色鱼药敌瓜虫的有效浓度为５ｍｇ／Ｌ,它和食盐合用可增强其药效。     

孔雀石绿治疗小瓜虫病试验

小瓜虫病的病原体是纤毛虫纲多子小瓜虫(Ichthyophthirius multifiliis Fouquet)。它是池塘养鱼中一种常见的流行病，一般在春末夏初的鱼苗、鱼种培育池里发生，以致引起鱼苗鱼种大量死亡。中国科学院水生生物研究所曾发表过文章，阐述可用硝酸亚汞浸洗或泼洒的办法进行防治，其他单位也曾报导过一些用药物防治小瓜虫病的方法。     

匙吻鲟小瓜虫病的观察与防治

匙吻鲟Ｐｏｌｙｏｄｏｎｓｐａｔｈｕｌａ隶属于匙吻鲟科Ｐｏｌｙｏｄｏｎ ｔｉｄａｅ,主要分布于美洲北部,我国从1990年开始从美国引进。通过10多年的引进与推广,在受精卵孵化、仔鱼培育、苗种培育等方面取得一定的进展,不少地方已开展了人工养殖。但在匙吻鲟苗种培育过程中,有些地方发生了小瓜虫病,致使苗种大量死亡,造成严重损失。现将我们1998年和2000年进行的小瓜虫病的观察与防治总结如下。1　基本情况匙吻鲟苗种系从美国引进受精卵,在实验室内经孵化、仔幼鱼培育而成。养殖容器为长方形(90ｃｍ×50ｃｍ×70ｃｍ)和圆形(直径135ｃ…     

小瓜虫抑动抗原研究综述

小瓜虫是重要的淡水鱼类寄生虫.小瓜虫抑动抗原是重要的保护性抗原,它在防治小瓜虫这类体表寄生虫方面有着巨大应用潜力.本文阐述了小瓜虫抑动抗原的发现过程及其生物学意义,并介绍了抑动抗原免疫学研究进展.本综述旨为抑动抗原在小瓜虫疫苗研制中的应用提供理论依据,也为其他体表寄生虫保护性抗原的研究提供参考.     

简并PCR扩增小瓜虫抑动抗原基因的ORF

抑动蛋白是小瓜虫(Ichthyophthiriusmultifiliis)体表纤毛的主要构成部分,也是宿主免疫系统发挥抗虫免疫时的主要识别抗原。根据已经报道的3种抑动蛋白N端及C端保守的多肽片断,设计了一对简并引物P6/P7,以小瓜虫分离株IchFJ9的基因组为模板,成功扩增了抑动蛋白编码区(ORF)的全长基因序列。扩增的iagFJ9基因全长1398bp,编码466个氨基酸,包含18个非标准密码子TAA(Glu,Q)推导的氨基酸序列包含6个以CPXGT为起始的串联重复单位,具有抑动蛋白的特征性结构。同源比较分析显示,扩增的iagFJ9基因与已知的小瓜虫抑动蛋白基因IAG52A基因具有88%同源率。证实了iagFJ9是一个新发现的抑动蛋白基因,用简并PCR技术去发现小瓜虫抑动蛋白基因家族新基因是可行的。     

Cell-mediated immune response of goldfish, Carassiusaurafus (L.), to Ichthyophthirius multifiliis

Goldfish, Carassius auratus (L.), were intraperitoneally injected with two doses of Ichthyophthirius multifiliis (each containing 2.3 × 10⁶ live tomites) in saline, 30 days apart. The control fish were injected with saline only. Two weeks after the last vaccination, fish of both groups were intradermally injected with 2.5 × 10⁵ live tomites for skin tests. The skin at the antigen-injected site of the vaccinated fish increased in thickness from 8 h onwards and reached a peak at 24 h. Histological study showed a heavy infiltration of mononuclear leucocytes at the antigen-injected site. In contrast, no such changes were encountered in control fish. The migration area of pronephros cells from the vaccinated fish was significantly inhibited, in vitro, compared to controls with the presence of antigens. These findings suggest that the tomite-vaccinated fish produced a cell-mediated immune response. However, vaccinated fish also exhibited significantly higher titres of immobilizing antibodies in their sera and mucus than the controls. Therefore, it is likely that both humoral and cell-mediated immune responses have to work closely together to eliminate the infectious tomites of I. multifiliis which succeed in penetrating the fish epithelial tissues.     

Antibody mediated immune response against Ichthyophthirius multifiliis using excised skin from channel catfish, Ictalurus punctatus (Rafinesque), immune to Ichthyophthirius

This study investigated antibody mediated immune response against Ichthyophthirius multifiliis (Ich) by determining whether theronts would retain the potential for reinfection, both in vitro and in vivo, after treatment with the culture fluid of excised skin from channel catfish, Ictalurus punctatus , immune to Ich. The invasion was reduced significantly ( P  < 0.05) for theronts treated with the immune culture fluid compared with those treated with the culture fluid from naive fish. The treatment of theronts with the immune culture fluid greatly reduced the size and survival of trophonts compared with those treated with the culture fluid from naive fish. Fewer fish were infected and the infection density was less for fish exposed to theronts treated with immune culture fluid. The infection was severe for fish invaded by theronts treated with the culture fluid from naive fish, with a high number of infected fish and heavy density of trophonts per fish. All fish were infected by Ich when exposed to the theronts treated with the immunoadsorbed culture fluid. In summary, results of this study show that cutaneous antibodies in the culture fluid of excised skin from immune fish significantly reduces theront infectivity by immobilizing or weakening theronts.     

Attempts to control Ichthyophthirius multifiliis Fouquet (Ciliophora: Ophryoglenidae) by chemotherapy and electrotherapy

Abstract. New methods were studied for the control of Ichthyophthirius muttifiliis Fouquet, one of the most serious parasites of fish. Totals of 272 fish, 354 I. Multifiliis trophozoites and 562,500 tomites were used in the screening of amprolium, ronidizole, and silver nitrate for parasite control. In addition, 1,465 trophozoites and 600 tomites were subjected to pulsed DC electrotherapy trials. Silver nitrate at 0·67 ppm was 100% effective in eradicating tomites, while ronidizole at 750 ppm gave 100% and 97% control of trophozoites and tomites, respectively. Amprolium and electrotherapy were both ineffective against trophozoites and tomites. Silver nitrate has promise as a safe and effective alternative to chemicals currently used to control I. multifiliis .     

Susceptibility of three strains of blue catfish,Ictalurus furcatus (Valenciennes), to Ichthyophthirius multifiliis

This study compared the susceptibility of three blue catfish strains (D&B, USDA 101 and USDA 102) to the parasite Ichthyophthirius multifiliis (Ich). In Trial I, a cohabitation study (all strains stocked communally) was conducted and fish were exposed to theronts at 0, 200, 1000, 5000 or 25 000 theronts fish^?1, respectively. All fish died when exposed to theronts at 5000 or 25 000 theronts fish^?1. When exposed to 1000 theronts fish^?1, USDA 102 strain of blue catfish showed significantly lower mortality (78.5%) compared to USDA 101 and D&B strains (92.7% and 100%). In Trial II, the same three strains of blue fish were evaluated for their susceptibility to Ich with strains challenged in separate tanks by adding Ich theronts at 0, 200 and 1000 theronts fish^?1, respectively. All D&B and USDA 101 blue catfish died; however, 42.3% of USDA 102 strain survived the infection when exposed to 1000 theronts per fish. The results indicate that there are differences among strains of blue catfish for susceptibility to Ich, and these differences will be useful in the development of improved catfish germplasm for commercial aquaculture.     

Ichthyophthirius multifiliis: axenic isolation and short-term maintenance in selected monophasic media

Abstract. All stages in the life cycle of Ichthyophthirius multifiliis were successfully isolated axenically, without loss of viability, by use of 1% penicillin:streptomycin solution (100IUcm⁻³:100μg cm⁻³). Survival and development of each stage was investigated in selected monophasic media at 20°C. Parasite survival was extended over that observed in water controls, suggesting that both parasitic and free-living stages are capable of some degree of nutrient uptake. The tomite survived within the cyst for a maximum of 22 days when incubated in EMEM without added serum (EMEM-S) and diluted 50:50 with distilled water. Viable theronts survived for up to 5 days within EMEM, 3 days longer than controls, and mature trophonts survived, with no further development, for up to 16 days within Glasgow modification of EMEM with added 10% serum. Successful encystment and excystment was dependent on water and occurred only in diluted media. Delayed encystment was achieved by incubation in concentrated media, the production of sterile, viable theronts being delayed for up to 96h within EMEM-S, 72h later than normally observed in the aquatic environment. The significance of the results are discussed with regard to the routine maintenance of the parasite and future prospects for in vitro culture.     

Apoptosis in Ichthyophthirius multifiliis is associated with expression of the Fas receptor of theronts

The expression of type I membrane Fas receptors on the surface of Ichthyophthirius multifiliis (Ich) theronts and the possible association between Fas expression and theront apoptosis induced by the immune antibody was examined. Fas receptors were detected on the theront surface using fluorescein isothiocyanate-conjugated mouse monoclonal antibody against Fas. Fas-positive theronts significantly increased with time during in vitro incubation and with increasing theront concentration. Furthermore, the immune cutaneous antibody induced theront apoptosis; however, Fas ligand did not. A highly significant correlation was noted between theront Fas expression and immune cutaneous antibody-induced theront apoptosis. Numbers of apoptotic theronts increased with increasing number of Fas-positive theronts. The data indicated that theront apoptosis induced by immune cutaneous antibody appears to be positively correlated with the expression of Fas on the surface of Ich theronts.