Taenia crassiceps: Fate of cysticerci following ingestion by the mouse

Cysticerci of Taenia crassiceps were administered to mice by gavage to determine whether enteral or parenteral infections would establish consistently. Some worms survived in the small intestine up to 16 days, whereas others penetrated through the gut wall into the peritoneal cavity within 24 hr. Similar proportions of different doses of worms reached the peritoneal cavity regardless of the size of the inoculum and sex or strain of mice used. In addiiton, it was shown that mice may acquire an intraperitoneal infection with T. crassiceps by eating the carcass of an infected mouse.     

猪囊尾蚴磷蛋白在毕赤酵母中的表达及初步应用

将猪囊虫磷蛋白P2基因克隆到毕赤酵母表达系统分泌性表达载体pPIC9K中,构建了重组表达载体pPIC9K-P2。经测序证明基因序列完全正确,从而大量制备重组质粒pPIC9K-P2,并用SalⅠ、BglⅡ 两种内切酶分别线性化,然后分别电转化毕赤酵母菌种GS115,采用G418抗性梯度筛选得到高拷贝重组菌株,利用MM和MD培养基鉴定重组菌株Mut表型,然后用甲醇进行诱导表达;并对表达产物通过SDS-PAGE、Westernblot和ELISA分析,结果表明,重组菌株成功地分泌表达了分子量大小为12.6kD,表达量占分泌总蛋白的33%,且具有免疫反应活性的重组磷蛋白,从而解决了囊虫病诊断抗原来源问题并为研制新型猪囊虫疫苗奠定了基础。     

Biotransformation of monoterpenoids, (−)- and menthols, terpinolene and carvotanacetone by Aspergillus species

Four monoterpenoids, (−)- and (+)-menthols, terpinolene and carvotanacetone were biotransformed by Aspergillus niger and several related species. Aspergillus niger converted (−)-menthol to 1-, 2-, 6-, 7-, and 9-hydroxymenthols and the mosquito repellent-active 8-hydroxymenthol. On the other hand, (+)-menthol was smoothly biotransformed by A. niger to give 7-hydroxymenthol. Aspergillus cellulosae biotransformed (−)-menthol specifically to 4-hydroxymenthol. Terpinolene and (−)-carvotanacetone were converted by A. niger to two , β-unsaturated ketones, a fenchane-type compound and diastereoisomeric p-menthane-2,9-diols and 8-hydroxycarvomenthol, respectively.     

Taenia saginata and T. hydatigena: intramuscular vaccination of calves with oncospheres

This is a preliminary attempt to immunize calves against bovine cysticercosis (Cestoda) by intramuscular injection of artificially hatched homologous or heterologous oncospheres. In the first two experiments five calves were vaccinated with the oncospheres of Taenia saginata. These calves, together with five controls, were subsequently challenged orally with the eggs of T. saginata. At autopsy all the vaccinated animals harbored a colony of living cysticerci at the site of injection. Three of these calves were completely protected against the oral challenge, and in the other two, only one, and two cysticerci, respectively were found in the sites of election. The five controls harbored 1154, 1680, 820, 960, and 1820 living cysticerci, respectively, in the sites of election.     

Prediction of viability of porcine neurocysticercosis with proton magnetic resonance spectroscopy: correlation with histopathology

Neurocysticercosis (NCC) is the most frequent parasitic disease of central nervous system. In our earlier study, we had observed creatine [(creatine + phosphocreatine); (tCr)] on ex vivo proton MR spectroscopy (1H MRS) in some of the cysticercus cyst fluid samples obtained from swine's brain parenchyma. In current study, swine brains of freshly slaughtered animals naturally infected with NCC were subjected to ex vivo magnetic resonance (MR) imaging on a 1.5Tesla MR system. Cysticercus cysts (n = 12) were removed from these brains and were labeled depending upon presence or absence of edema around cysts as observed on imaging. Cysticercus cyst fluid (100 microl) was subjected to different 1H MRS experiments and results were compared with histopathological examinations to look for any relationship between tCr and parameters like quantification of musculature, and cellular infiltration in wall of the parasite. Histopathology of cyst wall was categorized into two groups based on cellular characteristics and the amount of musculature. Grade I cysts (n = 5) with no or minimal inflammation and large amount of musculature showed tCr on 1H MRS. However, grade II cysts (n = 7) with profuse inflammation and less amount of musculature in the cyst wall lacked tCr. Higher amount of musculature in grade I cysts was associated with higher concentration of tCr in the cyst fluid (r2 = 0.93, P = 0.007). Creatine appears to be a marker of innocuous and viable NCC.     

Taenia crassiceps: Basic mechanisms of endocytosis in the cysticercus

The effects of glucose, yeast extract, fetal bovine serum albumin, and ruthenium red on endocytosis of smooth micropinocytotic vesicles (pinosomes) in the tegument of the cysticercus of Taenia crassiceps have been investigated stereologically. Glucose has been shown to stimulate pinocytosis, whether it was used alone or in combination with yeast extract or bovine serum albumin. Yeast extract was a stimulant of endocytosis. Bovine serum albumin was the most potent stimulant of all the substances investigated in this study. Although the time of incubation in ruthenium red was the same for all incubation experiments, varied numbers of ruthenium red-containing pinosomes were observed in different experiments. The role of ruthenium red as a stimulant and/or initiator of endocytosis and the possible explanations for differences in ruthenium red uptake are discussed.     

The stimulation of resistance in sheep to Fasciola hepatica by infection with Cysticercus tenuicollis

Infection of sheep with Cysticerus tenuicollis for 12 weeks generated a high level of protection (> 95%) against intra-ruminal challenge with metacercariae of Fasciola hepatica as measured by recovery of flukes from liver and bile ducts and counts of fluke eggs in faeces. The animals were resistant to Fasciola whether challenge was superimposed upon the cestode infection or after removal of the cestode with mebendazole.Previous infection with C. tenuicollis also protected against the pathogenic effects of challenge infection with F. hepatica. Liver fibrosis was much less extensive in resistant sheep than controls and PCV's were not affected although these were reduced during fluke infection in the control animals.     

猪囊尾蚴CE18重组蛋白的复性纯化及抗原性鉴定

猪囊尾蚴CE18重组蛋白(rCE18)在大肠杆菌表达后形成包涵体, 为了获得高纯度的、有生物活性的rCE18, 本研究采用超声破碎菌体, 0.2%、2% DOC(脱氧胆酸钠)逐次洗涤包涵体及0.9% SKL(十二烷基肌氨酸钠)溶解包涵体后, 利用透析与凝胶过滤层析技术相结合对rCE18进行复性和纯化。同时, 采用GST-FF亲和柱层析及SDS-PAGE胶回收蛋白两种方法纯化rCE18, 比较三者的纯化效果。并通过间接ELISA检测复性蛋白的生物学活性。结果表明: 经透析与凝胶层析复性纯化后的rCE18蛋白的纯度可达到60%以上, 活性回收率为41.3%, 间接ELISA证实, 复性后的rCE18蛋白能特异性识别猪囊虫阳性血清, 检测敏感性高达97.2%, 与全囊虫抗原检测的符合率为100%。本试验初步建立了猪囊尾蚴rCE18包涵体纯化及复性的有效方法, 为猪囊尾蚴rCE18蛋白的诊断应用奠定了基础。