oocyst Dotaz Zobrazit nápovědu
- MeSH
- Apicomplexa patogenita růst a vývoj účinky léků MeSH
- dezinficiencia MeSH
- kokcidióza veterinární MeSH
- skot MeSH
- Check Tag
- skot MeSH
- MeSH
- feces parazitologie MeSH
- kokcidióza diagnóza MeSH
- protozoální infekce diagnóza MeSH
- Publikační typ
- kazuistiky MeSH
Pojednáno o problému, jakými prostředky možno destruovat oocysty v odchovnách drůbeže zamořených kokcidiozou a uvedena řada přípravků, jimiž je možno toho dosáhnout za předpokladu důkladného očištění podlah a zařízení od|choven
OBJECTIVES: Studies on the pathogenesis and immune responses of Cryptosporidium infection and development of drugs and vaccines use mostly immunocompromised mouse models. In this study, we establish an immunocompetent mouse model of cryptosporidiosis with high intensity and long duration of infection. METHODS: We have obtained a Cryptosporidium tyzzeri isolate from laboratory mice, and infect adult C57BL/6 J mice experimentally with the isolate for determinations of infectivity, infection patterns, pathological changes, and transcriptomic responses. RESULTS: The isolate has an ID50 of 5.2 oocysts, with oocyst shedding lasting at high levels for >2 months. The oocyst shedding is boosted by immunosuppression of animals and suppressed by paromomycin treatment. The isolate induces strong inflammatory and acquired immune responses, but down-regulates the expression of α-defensins in epithelium. Comparative genomics analysis has revealed significant sequence differences from other isolates in subtelomeric genes. The down-regulation of the expression of α-defensins may be responsible for the high-intensity and long-lasting infection in this animal model. CONCLUSIONS: The immunocompetent mouse model of cryptosporidiosis developed has the advantages of high oocyst shedding intensity and long oocyst shedding duration. It provides an effective mechanism for the propagation of Cryptosporidium, evaluations of potential therapeutics, and studies of pathogen biology and immune responses.
- MeSH
- alfa-defensiny * MeSH
- Cryptosporidium parvum * MeSH
- Cryptosporidium * fyziologie MeSH
- feces MeSH
- kryptosporidióza * patologie MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- oocysty MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This study aimed to evaluate and document the excystation process of Cryptosporidium muris oocysts in various incubation media, and to monitor the behaviour of excysting and freshly excysted sporozoites. A test of oocyst viability, using fluorescent double staining with fluorescein diacetate and propidium iodide, was performed prior to each experimental assay. Light microscope observations confirmed that relatively often only three sporozoites were released; the fourth one either left the oocyst later together with a residual body or remained trapped within the oocyst wall. These results suggest that successful oocyst excystation is not limited by the viability of all four sporozoites. Darkening of oocysts to opaque and their specific movement (the so-called "oocyst dancing") preceded the final excystation and liberation of sporozoites, while the dormant oocysts appeared refractive. The process of excystation in C. muris is not gradual as generally described in cryptosporidia but very rapid in an eruptive manner. Experiments were performed using oocysts stored at 4 °C for various time periods, as well as oocysts freshly shed from host rodents (Mastomys coucha) of different ages. The most suitable medium supporting high excystation rate (76 %) and prolonged motility of sporozoites was RPMI 1640, enriched with 5 % bovine serum albumin (BSA). Our results emphasize that to reliably evaluate the success of in vitro excystation of cryptosporidia, not only the number of released sporozoites in a set time period should be taken into consideration but also their subsequent activity (motility), as it is expected to be essential for the invasion of host cells.
- MeSH
- Cryptosporidium účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- kultivační média farmakologie MeSH
- mikrobiální viabilita účinky léků MeSH
- oocysty fyziologie MeSH
- propidium MeSH
- sporozoiti účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Excystation of sporozoites of Cryptosporidium parvum from oocysts is essential for successful in vitro assays. It has also been traditionally used as a measure for oocyst viability and infectivity. Laboratories use various excystation protocols so there is a need to clarify which method is the best. In this study, six different protocols for in vitro excystation of C. parvum oocysts were compared to find the most efficient excystation method (expressed as percentage excystation). Tested protocols differed in chemical pre-incubation steps, excystation media or time of incubation. There were significant differences in percentage of excysted oocysts among groups excysted by different methods. There were also significant differences in percentage of excysted oocysts between methods using pre-incubation with sodium hypochlorite and those without. The other variables examined; the presence of trypsin, kind of excystation medium and the incubation time, did not show statistical differences in percentage excystation among groups. Pre-incubation steps which included sodium hypochlorite, enhancing the permeability of the oocysts were found to increase the excystation ratio and methods using this step were the most effective.
- MeSH
- chlornan sodný farmakologie MeSH
- Cryptosporidium parvum účinky léků fyziologie MeSH
- kultivační média farmakologie MeSH
- oocysty účinky léků MeSH
- parazitologie metody MeSH
- permeabilita účinky léků MeSH
- trypsin farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
