The effects of nitroquine on the sporogony of Plasmodium yoelii werestudied with electron microscope.The drug was given by feeding female mosqui-toes directly in the form of mixture with sucrose solution.Scanning elec...The effects of nitroquine on the sporogony of Plasmodium yoelii werestudied with electron microscope.The drug was given by feeding female mosqui-toes directly in the form of mixture with sucrose solution.Scanning electronmicroscopic studies revealed that the oocysts were smaller and markedly degener-ated.Surface of the oocysts was rough and uneven.Under transmission electronmicroscope,the cytoplasm of the affected oocysts contained vacuoles.Mitochondrial and nuclear membrane was damaged.The number of residualbodies increased.Formation of sporoblast did not occur in most of the affectedoocysts.The nuclear membranes of the degenerated sporozoites became thick-ened and the density of nucleus matrix markedly decreased.The results indicatedthat nuclei and the membrane system were mainly affected.展开更多
Malaria endemic zones are mostly located on third world countries, where antimalarials are not easily found or patients cannot afford them, and in consequence, they must turn toward natural products or phytomedicines....Malaria endemic zones are mostly located on third world countries, where antimalarials are not easily found or patients cannot afford them, and in consequence, they must turn toward natural products or phytomedicines. In the present study, the effect of Hinotnia latiflora (Hl) methanolic stem bark extract (HlMeOHe) on the ultrastructure of the asexual intraerythrocytic stages of Plasmodium yoelii yoelii (Pyy) after a Peters’ four-day oral treatment was assessed by transmission electron microscopy (TEM), as well as the parasite development on blood smears, analyzed by light microscopy. Likewise, extract was subjected to qualitative tests adopting standard procedures for identification of phytoconstituents;its antioxidant activity was evaluated according to the method of Brand-Williams and by the radical cation decolorization assay. Results showed higher percentage of rings and lower percentage of trophozoites and schizonts in the treated animals, in comparison with those of the control groups, which demonstrated lower percentage of rings and trophozoites, and schizonts in higher number. Images of TEM showed in some treated parasites, mild parasite membranes, organelle swelling and ribosomal depletion. The phytochemical profile demonstrated that the extract contains alkaloids, tannis, steroids, terpenoids, flavonoids, phenolics and saponins. The obtained values of the half maximal inhibitory concentration (IC50) in μg/mL, for both antioxidant assays were of 423.83 and 202.95 respectively. It is concluded that HlMeOHe altered the development of the intraerythrocytic asexual stages and the ultrastructure of Pyy, and due to its phytochemical constituents, showed an in vitro antioxidant activity.展开更多
The isolation and study of genes that are differentially expressed in malaria infected mosquitoes is important for the elucidation of basic molecular mechanisms underlying vector parasite interactions. When screenin...The isolation and study of genes that are differentially expressed in malaria infected mosquitoes is important for the elucidation of basic molecular mechanisms underlying vector parasite interactions. When screening against a previously established cDNAs pool representing specifically expressed genes in the mosquito Anopheles stephensi infected by Plasmodium yoelii, it was found that one of these encodes a protein with extensive sequence similarity to the Drosophila melanogaster ubiquitin C terminal hydrolase(UCTH). Similarity alignment showed that the fragment is 89% identical at amino acid level to the corresponding region of the known An. gambiae EST sequence, as well as 63% identical to that of both the fruitfly and human sequence. Virtual Northern blot expression dynamics of the gene indicated that it was up regulated significantly in the mosquito at least 1 7 days post infection, consistent with the critical transition stages of midgut invasion and relocation of sporozoites from the oocysts to the salivary glands during parasite development. Rather little is known about the role of the ubiquitin pathway in the activation of the mosquito innate immune system. The results indicate that the gene is related to malaria infection in mosquito. The cloning and expression profile analysis of As UCTH enables us to make predictions as to the roles it may play during malaria infection.展开更多
Signal transducer and activator of transcription （STAT） proteins play an important role in cytokine signaling pathways and regulation of immune responses. The balance of the phosphorylated （activated） STAT1 （pST...Signal transducer and activator of transcription （STAT） proteins play an important role in cytokine signaling pathways and regulation of immune responses. The balance of the phosphorylated （activated） STAT1 （pSTAT1） and STAT3 （pSTAT3） has been documented in cancer immunology. In this study, we investigated the dynamic balance of pSTAT1 and pSTAT3 in C57BL/6 mice infected with either a nonlethal （Py17XNL） or lethal （Py17XL） strain of Plasmodium yoelii. Both Py17XNL and Py17XL infections induced a maximum activation of STAT1 and STAT3 on the first day after parasite inoculation. Additionally, the Py17XNL infection induced a pSTAT1- dominant response in mice during the early stage of infection, with the resolution of parasitemia. In contrast, Py17XL infection induced a pSTAT3-dominant response during the early phase of infection, with the death of the animals. Our results indicated that maximum activation of STAT1 and STAT3 occurred much earlier than the peak levels of cytokines induced by Plasmodium yoelii infection based on previous reports and that infection with Py17XNL and Py17XL induced different dynamic patterns of pSTAT1 and pSTAT3 balance.展开更多
Background:Leukaemia is a malignant leukocyte disorder with a high fatality rate,and current treatments for this disease are unsatisfactory.Therefore,new therapeutic strategies for leukaemia must be developed.Malaria ...Background:Leukaemia is a malignant leukocyte disorder with a high fatality rate,and current treatments for this disease are unsatisfactory.Therefore,new therapeutic strategies for leukaemia must be developed.Malaria parasite infection has been shown to be effective at combating certain neoplasms in animal experiments.This study is to demonstrate the anti-leukaemia activity of malaria parasite Plasmodium yoelii(P.yoelii)infection,.Methods:In this study,the proportion of CD3,CD19,CD11b and Mac-3 cells was analysed by flow cytometry;the levels of IFN-γand TNF-αin individual serum samples were measured by enzyme-linked immunosorbent assay,and the phagocytic activity of macrophages and natural killer(NK)cell activity were measured by flow cytometry.Results:We found that P.yoelii infection significantly attenuated the growth of WEHI-3 cells in mice.In addition,tumor cell infiltration into the murine liver and spleen was markedly reduced.We also demonstrated that malaria parasite infection elicited anti-leukaemia activity by promoting immune responses,including increasing the surface markers of T cells(CD3)and B cells(CD19);decreasing the surface markers of monocytes(CD11b)and macrophages(Mac-3);inducing the secretion of IFN-γand TNF-α;and increasing NK cell and macrophage activity.Conclusions:Malaria parasite infection significantly decreases the number of myeloblasts and inhibits neoplasm proliferation in mice.In addition,malaria parasite infection inhibits murine leukaemia by promoting immune responses.展开更多
Mannliche Wistar Ratten wurden intravenos mit 700 ×103 Sporozoiten von Plasmodium yoelii infiziert. Den Versuchstieren wurde 2 und 24 Stunden nach der Infektion 700 mg/kg eines Extraktes von Chrysanthemum morifol...Mannliche Wistar Ratten wurden intravenos mit 700 ×103 Sporozoiten von Plasmodium yoelii infiziert. Den Versuchstieren wurde 2 und 24 Stunden nach der Infektion 700 mg/kg eines Extraktes von Chrysanthemum morifolium in die Bauchhohle gespritzt. 40 Stunden nach der Infektion wurden die Tiere getotet und in Leberdunnschnitten wurde die exoerythrozytare Schizogonie bestimmt. Es wurde gefunden, daβ zwar das Eindringen der Sporozoiten in die Leberzellen nicht gehemmt wurde,jedoch die intrazellulare Reifung zu infektiosen Formen der exoerythrozytare Schizogonie deutlich gehemmt war.展开更多
Anopheles stephenst, infected with Plasinodium yoelii, was fed with 10% sucrose solution contatning 1% difluoromethylornithine (DFMO) to induce oocyst degeneration of the malaria parasites. On the 11th day after infec...Anopheles stephenst, infected with Plasinodium yoelii, was fed with 10% sucrose solution contatning 1% difluoromethylornithine (DFMO) to induce oocyst degeneration of the malaria parasites. On the 11th day after infection, the effects of mosquito hemocytes On the normal and degenerated oocysts were observed under transmission electron microscope. In the control group, no hemocyte could be found around the normally-developed oocysts. In the DFMO-treated group, all the oocysts underwent degeneration in various degrees and some of them were melanized. All the oocysts were attached by one or more hemocytes of the kind of granulocytes.There were many granules with microtubular structure in the cytoplasm of the hemocytes and in the space between the hemocyte and the oocyst. The findings suggest that the degeneration of oocysts can attract the hemocytes to attach around them and the latter can release granules and possibly other substances to cause encapsulation and melanization of the oocvsts.展开更多
文摘The effects of nitroquine on the sporogony of Plasmodium yoelii werestudied with electron microscope.The drug was given by feeding female mosqui-toes directly in the form of mixture with sucrose solution.Scanning electronmicroscopic studies revealed that the oocysts were smaller and markedly degener-ated.Surface of the oocysts was rough and uneven.Under transmission electronmicroscope,the cytoplasm of the affected oocysts contained vacuoles.Mitochondrial and nuclear membrane was damaged.The number of residualbodies increased.Formation of sporoblast did not occur in most of the affectedoocysts.The nuclear membranes of the degenerated sporozoites became thick-ened and the density of nucleus matrix markedly decreased.The results indicatedthat nuclei and the membrane system were mainly affected.
文摘Malaria endemic zones are mostly located on third world countries, where antimalarials are not easily found or patients cannot afford them, and in consequence, they must turn toward natural products or phytomedicines. In the present study, the effect of Hinotnia latiflora (Hl) methanolic stem bark extract (HlMeOHe) on the ultrastructure of the asexual intraerythrocytic stages of Plasmodium yoelii yoelii (Pyy) after a Peters’ four-day oral treatment was assessed by transmission electron microscopy (TEM), as well as the parasite development on blood smears, analyzed by light microscopy. Likewise, extract was subjected to qualitative tests adopting standard procedures for identification of phytoconstituents;its antioxidant activity was evaluated according to the method of Brand-Williams and by the radical cation decolorization assay. Results showed higher percentage of rings and lower percentage of trophozoites and schizonts in the treated animals, in comparison with those of the control groups, which demonstrated lower percentage of rings and trophozoites, and schizonts in higher number. Images of TEM showed in some treated parasites, mild parasite membranes, organelle swelling and ribosomal depletion. The phytochemical profile demonstrated that the extract contains alkaloids, tannis, steroids, terpenoids, flavonoids, phenolics and saponins. The obtained values of the half maximal inhibitory concentration (IC50) in μg/mL, for both antioxidant assays were of 423.83 and 202.95 respectively. It is concluded that HlMeOHe altered the development of the intraerythrocytic asexual stages and the ultrastructure of Pyy, and due to its phytochemical constituents, showed an in vitro antioxidant activity.
文摘The isolation and study of genes that are differentially expressed in malaria infected mosquitoes is important for the elucidation of basic molecular mechanisms underlying vector parasite interactions. When screening against a previously established cDNAs pool representing specifically expressed genes in the mosquito Anopheles stephensi infected by Plasmodium yoelii, it was found that one of these encodes a protein with extensive sequence similarity to the Drosophila melanogaster ubiquitin C terminal hydrolase(UCTH). Similarity alignment showed that the fragment is 89% identical at amino acid level to the corresponding region of the known An. gambiae EST sequence, as well as 63% identical to that of both the fruitfly and human sequence. Virtual Northern blot expression dynamics of the gene indicated that it was up regulated significantly in the mosquito at least 1 7 days post infection, consistent with the critical transition stages of midgut invasion and relocation of sporozoites from the oocysts to the salivary glands during parasite development. Rather little is known about the role of the ubiquitin pathway in the activation of the mosquito innate immune system. The results indicate that the gene is related to malaria infection in mosquito. The cloning and expression profile analysis of As UCTH enables us to make predictions as to the roles it may play during malaria infection.
基金for providing the Py17XNL strain and the Malaria Research and Reference Reagent Resource Center (MR4, MAL88851-01265293) for donating the Py17XL strain of Plasmodium yoelii.
文摘Signal transducer and activator of transcription （STAT） proteins play an important role in cytokine signaling pathways and regulation of immune responses. The balance of the phosphorylated （activated） STAT1 （pSTAT1） and STAT3 （pSTAT3） has been documented in cancer immunology. In this study, we investigated the dynamic balance of pSTAT1 and pSTAT3 in C57BL/6 mice infected with either a nonlethal （Py17XNL） or lethal （Py17XL） strain of Plasmodium yoelii. Both Py17XNL and Py17XL infections induced a maximum activation of STAT1 and STAT3 on the first day after parasite inoculation. Additionally, the Py17XNL infection induced a pSTAT1- dominant response in mice during the early stage of infection, with the resolution of parasitemia. In contrast, Py17XL infection induced a pSTAT3-dominant response during the early phase of infection, with the death of the animals. Our results indicated that maximum activation of STAT1 and STAT3 occurred much earlier than the peak levels of cytokines induced by Plasmodium yoelii infection based on previous reports and that infection with Py17XNL and Py17XL induced different dynamic patterns of pSTAT1 and pSTAT3 balance.
文摘Background:Leukaemia is a malignant leukocyte disorder with a high fatality rate,and current treatments for this disease are unsatisfactory.Therefore,new therapeutic strategies for leukaemia must be developed.Malaria parasite infection has been shown to be effective at combating certain neoplasms in animal experiments.This study is to demonstrate the anti-leukaemia activity of malaria parasite Plasmodium yoelii(P.yoelii)infection,.Methods:In this study,the proportion of CD3,CD19,CD11b and Mac-3 cells was analysed by flow cytometry;the levels of IFN-γand TNF-αin individual serum samples were measured by enzyme-linked immunosorbent assay,and the phagocytic activity of macrophages and natural killer(NK)cell activity were measured by flow cytometry.Results:We found that P.yoelii infection significantly attenuated the growth of WEHI-3 cells in mice.In addition,tumor cell infiltration into the murine liver and spleen was markedly reduced.We also demonstrated that malaria parasite infection elicited anti-leukaemia activity by promoting immune responses,including increasing the surface markers of T cells(CD3)and B cells(CD19);decreasing the surface markers of monocytes(CD11b)and macrophages(Mac-3);inducing the secretion of IFN-γand TNF-α;and increasing NK cell and macrophage activity.Conclusions:Malaria parasite infection significantly decreases the number of myeloblasts and inhibits neoplasm proliferation in mice.In addition,malaria parasite infection inhibits murine leukaemia by promoting immune responses.
文摘Mannliche Wistar Ratten wurden intravenos mit 700 ×103 Sporozoiten von Plasmodium yoelii infiziert. Den Versuchstieren wurde 2 und 24 Stunden nach der Infektion 700 mg/kg eines Extraktes von Chrysanthemum morifolium in die Bauchhohle gespritzt. 40 Stunden nach der Infektion wurden die Tiere getotet und in Leberdunnschnitten wurde die exoerythrozytare Schizogonie bestimmt. Es wurde gefunden, daβ zwar das Eindringen der Sporozoiten in die Leberzellen nicht gehemmt wurde,jedoch die intrazellulare Reifung zu infektiosen Formen der exoerythrozytare Schizogonie deutlich gehemmt war.
文摘Anopheles stephenst, infected with Plasinodium yoelii, was fed with 10% sucrose solution contatning 1% difluoromethylornithine (DFMO) to induce oocyst degeneration of the malaria parasites. On the 11th day after infection, the effects of mosquito hemocytes On the normal and degenerated oocysts were observed under transmission electron microscope. In the control group, no hemocyte could be found around the normally-developed oocysts. In the DFMO-treated group, all the oocysts underwent degeneration in various degrees and some of them were melanized. All the oocysts were attached by one or more hemocytes of the kind of granulocytes.There were many granules with microtubular structure in the cytoplasm of the hemocytes and in the space between the hemocyte and the oocyst. The findings suggest that the degeneration of oocysts can attract the hemocytes to attach around them and the latter can release granules and possibly other substances to cause encapsulation and melanization of the oocvsts.
