The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Brian L Fredensborg - One of the best experts on this subject based on the ideXlab platform.
-
establishment success of the beetle tapeworm hymenolepis diminuta depends on dose and host body condition
Insects, 2018Co-Authors: Suraj Dhakal, Nicolai V Meyling, Sebastian Micki Buss, Elizabeth J Cassidy, Brian L FredensborgAbstract:Parasite effects on host fitness and immunology are often intensity-dependent. Unfortunately, only few experimental studies on insect-parasite interactions attempt to control the level of infection, which may contribute substantial variation to the fitness or immunological parameters of interest. The tapeworm Hymenolepis diminuta-flour beetle Tenebrio molitor model-has been used extensively for ecological and evolutionary host-parasite studies. Successful establishment of H. diminuta Cysticercoids in T. molitor relies on ingestion of viable eggs and penetration of the gut wall by the onchosphere. Like in other insect models, there is a lack of standardization of the infection load of Cysticercoids in beetles. The aims of this study were to: (1) quantify the relationship between exposure dose and establishment success across several H. diminuta egg concentrations; and (2) test parasite establishment in beetles while experimentally manipulating host body condition and potential immune response to infection. Different egg concentrations of H. diminuta isolated from infected rat feces were fed to individual beetles 7-10 days after eclosion and beetles were exposed to starvation, wounding, or insertion of a nylon filament one hour prior to infection. We found that the establishment of Cysticercoids in relation to exposure dose could be accurately predicted using a power function where establishment success was low at three lowest doses and higher at the two highest doses tested. Long-term starvation had a negative effect on cysticercoid establishment success, while insertion of a nylon filament and wounding the beetles did not have any effect compared to control treatment. Thus, our results show that parasite load may be predicted from the exposure dose within the observed range, and that the relationship between dose and parasite establishment success is able to withstand some changes in host body condition.
-
efficacy of condensed tannins against larval hymenolepis diminuta cestoda in vitro and in the intermediate host tenebrio molitor coleoptera in vivo
Veterinary Parasitology, 2015Co-Authors: Suraj Dhakal, Nicolai V Meyling, Andrew R Williams, Irene Muellerharvey, Christos Fryganas, C M O Kapel, Brian L FredensborgAbstract:Natural anti-parasitic compounds in plants such as condensed tannins (CT) have anthelmintic properties against a range of gastrointestinal nematodes, but for other helminths such effects are unexplored. The aim of this study was to assess the effects of CT from three different plant extracts in a model system employing the rat tapeworm, Hymenolepis diminuta, in its intermediate host, Tenebrio molitor. An in vitro study examined infectivity of H. diminuta Cysticercoids (excystation success) isolated from infected beetles exposed to different concentrations of CT extracts from pine bark (PB) (Pinus sps), hazelnut pericarp (HN) (Corylus avellana) or white clover flowers (WC) (Trifolium repens), in comparison with the anthelmintic drug praziquantel (positive control). In the in vitro study, praziquantel and CT from all three plant extracts had dose-dependent inhibitory effects on cysticercoid excystation. The HN extract was most effective at inhibiting excystation, followed by PB and WC. An in vivo study was carried out on infected beetles (measured as cysticercoid establishment) fed different doses of PB, HN and praziquantel. There was a highly significant inhibitory effect of HN on cysticercoid development (p = 0.0002). Overall, CT showed a promising anti-cestodal effect against the metacestode stage of H. diminuta.
Tsuyoshi Takami - One of the best experts on this subject based on the ideXlab platform.
-
Hymenolepis nana: immunity against oncosphere challenge in mice previously given viable or non-viable oncospheres of H. nana, H. diminuta, H. microstoma and Taenia taeniaeformis.
International journal for parasitology, 1991Co-Authors: Akira Ito, Kazuo Onitake, Junko Sasaki, Tsuyoshi TakamiAbstract:Abstract When mice, previously given oral inoculation with viable oncospheres of the heterologous cestode species ( Hymenolepis diminuta, H. microstoma. Taenia taeniaeformis ) and the homologous one ( H. nana ), were challenged with oncospheres of H. nana 4 days after the primary inoculation, they showed strong and complete resistance to H. nana challenge, respectively. However, the resistance was not evoked in mice given either infective eggs of Toxocara canis or non-viable oncospheres of all cestode species examined. Congenitally athymic nude mice given viable oncospheres did not show any resistance to H. nana either. Eosinophil infiltration around Cysticercoids of H. nana in the intestinal villi appeared to be more prominent in mice previously given viable oncospheres of H. diminuta than in mice given non-viable oncospheres or PBS only. Some of the eosinophils in the villus harboring cysticercoid(s) of H. nana invaded the epithelia in the former, whereas all eosinophils remained in the lamina propria in the latter. There was almost no eosinophil infiltration in nude mice. Microscopic observations revealed that oncospheres of H. diminuta , which require beetles as the intermediate host like H. microstoma , could invade the mouse intestinal tissue. Therefore, it is strongly suggested that the strong cross resistance to H. nana in mice, induced by oncospheres of all heterologous cestode species, is thymus-dependent and due to oncospheral invasion into the intestinal tissue of mice.
Suraj Dhakal - One of the best experts on this subject based on the ideXlab platform.
-
establishment success of the beetle tapeworm hymenolepis diminuta depends on dose and host body condition
Insects, 2018Co-Authors: Suraj Dhakal, Nicolai V Meyling, Sebastian Micki Buss, Elizabeth J Cassidy, Brian L FredensborgAbstract:Parasite effects on host fitness and immunology are often intensity-dependent. Unfortunately, only few experimental studies on insect-parasite interactions attempt to control the level of infection, which may contribute substantial variation to the fitness or immunological parameters of interest. The tapeworm Hymenolepis diminuta-flour beetle Tenebrio molitor model-has been used extensively for ecological and evolutionary host-parasite studies. Successful establishment of H. diminuta Cysticercoids in T. molitor relies on ingestion of viable eggs and penetration of the gut wall by the onchosphere. Like in other insect models, there is a lack of standardization of the infection load of Cysticercoids in beetles. The aims of this study were to: (1) quantify the relationship between exposure dose and establishment success across several H. diminuta egg concentrations; and (2) test parasite establishment in beetles while experimentally manipulating host body condition and potential immune response to infection. Different egg concentrations of H. diminuta isolated from infected rat feces were fed to individual beetles 7-10 days after eclosion and beetles were exposed to starvation, wounding, or insertion of a nylon filament one hour prior to infection. We found that the establishment of Cysticercoids in relation to exposure dose could be accurately predicted using a power function where establishment success was low at three lowest doses and higher at the two highest doses tested. Long-term starvation had a negative effect on cysticercoid establishment success, while insertion of a nylon filament and wounding the beetles did not have any effect compared to control treatment. Thus, our results show that parasite load may be predicted from the exposure dose within the observed range, and that the relationship between dose and parasite establishment success is able to withstand some changes in host body condition.
-
efficacy of condensed tannins against larval hymenolepis diminuta cestoda in vitro and in the intermediate host tenebrio molitor coleoptera in vivo
Veterinary Parasitology, 2015Co-Authors: Suraj Dhakal, Nicolai V Meyling, Andrew R Williams, Irene Muellerharvey, Christos Fryganas, C M O Kapel, Brian L FredensborgAbstract:Natural anti-parasitic compounds in plants such as condensed tannins (CT) have anthelmintic properties against a range of gastrointestinal nematodes, but for other helminths such effects are unexplored. The aim of this study was to assess the effects of CT from three different plant extracts in a model system employing the rat tapeworm, Hymenolepis diminuta, in its intermediate host, Tenebrio molitor. An in vitro study examined infectivity of H. diminuta Cysticercoids (excystation success) isolated from infected beetles exposed to different concentrations of CT extracts from pine bark (PB) (Pinus sps), hazelnut pericarp (HN) (Corylus avellana) or white clover flowers (WC) (Trifolium repens), in comparison with the anthelmintic drug praziquantel (positive control). In the in vitro study, praziquantel and CT from all three plant extracts had dose-dependent inhibitory effects on cysticercoid excystation. The HN extract was most effective at inhibiting excystation, followed by PB and WC. An in vivo study was carried out on infected beetles (measured as cysticercoid establishment) fed different doses of PB, HN and praziquantel. There was a highly significant inhibitory effect of HN on cysticercoid development (p = 0.0002). Overall, CT showed a promising anti-cestodal effect against the metacestode stage of H. diminuta.
Kenichi Okamoto - One of the best experts on this subject based on the ideXlab platform.
-
Reconsideration of the effects of selfing on the viability of Hymenolepis nana
International journal for parasitology, 1993Co-Authors: F. Nakamura, Kenichi OkamotoAbstract:A single cysticercoid of Hymenolepis nana was orally administered to an SPF-ICR strain mouse which was congenitally free of H. nana. Gravid proglottids of the resulting adult worm (parental generation) were fed to flour beetles, Tribolium confusum. Six or 14 days later, one cysticercoid from the beetles was fed to each mouse. Gravid proglottids were subsequently recovered and fed to beetles as above. This procedure was repeated for more than 20 generations. H. nana can survive repeated selfing and has been maintained for at least 27 generations. No decrease in the proportion of Cysticercoids into adults with repeated selfing was observed in our experiments. Our results appear to conflict somewhat with results reported previously. This discrepancy may be due to a difference in mice used as experimental hosts, although some other causal factors, e.g. fluctuation of infective rate or difference in the varieties of H. nana strain used cannot be excluded.
Akira Ito - One of the best experts on this subject based on the ideXlab platform.
-
hymenolepis microstoma direct life cycle in immunodeficient mice
Journal of Helminthology, 2004Co-Authors: Jorn Andreassen, Akira Ito, Mamoru Ito, Minoru Nakao, Kazuhiro NakayaAbstract:The mouse bile duct tapeworm Hymenolepis microstoma requires beetles as the obligatory intermediate host. However, when congenitally athymic NMRI-nu mice were infected with the mature tapeworm and allowed to eat their own faeces with tapeworm eggs, the oncospheres penetrated the intestinal tissue and developed to Cysticercoids. After excysting, growth to adult worms occurs in the lumen of the small intestine and bile duct. Furthermore, the same happened when NMRI-nu mice, non-obese diabetic severe combined immunodeficiency (NOD/Shi-scid) mice and NOD/Shi-scid, IL-2 Rgamma(null) (NOG) mice were orally inoculated with shell-free eggs of this parasite. Differences between the Cysticercoids of H. microstoma and H. nana developed in the mouse intestinal tissues were: (i) the time course for the development of fully matured Cysticercoids of H. microstoma in mice was about 11 days but only 4 days for H. nana; and (ii) Cysticercoids of H. microstoma developed in mice had a tail while those of H. nana had none.
-
Eosinophil chemotactic factors from Cysticercoids of Hymenolepis nana
Journal of helminthology, 1998Co-Authors: A. Niwa, Kazuhito Asano, Akira ItoAbstract:A comparative study of eosinophil chemotactic factors was carried out using Cysticercoids and oncospheres of Hymenolepis nana. Cysticercoids showed twice the chemotactic activity for eosinophils than the oncospheres. Eosinophilia induced by oncospheres and Cysticercoids observed in secondary and primary infections, respectively, were discussed from the view point of the immunobiology of this parasite.
-
Hymenolepis nana: immunity against oncosphere challenge in mice previously given viable or non-viable oncospheres of H. nana, H. diminuta, H. microstoma and Taenia taeniaeformis.
International journal for parasitology, 1991Co-Authors: Akira Ito, Kazuo Onitake, Junko Sasaki, Tsuyoshi TakamiAbstract:Abstract When mice, previously given oral inoculation with viable oncospheres of the heterologous cestode species ( Hymenolepis diminuta, H. microstoma. Taenia taeniaeformis ) and the homologous one ( H. nana ), were challenged with oncospheres of H. nana 4 days after the primary inoculation, they showed strong and complete resistance to H. nana challenge, respectively. However, the resistance was not evoked in mice given either infective eggs of Toxocara canis or non-viable oncospheres of all cestode species examined. Congenitally athymic nude mice given viable oncospheres did not show any resistance to H. nana either. Eosinophil infiltration around Cysticercoids of H. nana in the intestinal villi appeared to be more prominent in mice previously given viable oncospheres of H. diminuta than in mice given non-viable oncospheres or PBS only. Some of the eosinophils in the villus harboring cysticercoid(s) of H. nana invaded the epithelia in the former, whereas all eosinophils remained in the lamina propria in the latter. There was almost no eosinophil infiltration in nude mice. Microscopic observations revealed that oncospheres of H. diminuta , which require beetles as the intermediate host like H. microstoma , could invade the mouse intestinal tissue. Therefore, it is strongly suggested that the strong cross resistance to H. nana in mice, induced by oncospheres of all heterologous cestode species, is thymus-dependent and due to oncospheral invasion into the intestinal tissue of mice.
