Microsporidia are highly specialized obligate intracellular parasites that can infect a wide variety of animals ranging from protists to mammals. The classical concept of the parasite invasion into a host cell involve...Microsporidia are highly specialized obligate intracellular parasites that can infect a wide variety of animals ranging from protists to mammals. The classical concept of the parasite invasion into a host cell involves its polar tube acting as a needle-syringe system. However, recent studies show microsporidian spores can also gain access to host cells by phagocytosis. The present study investigated the phagocytic uptake process of causative agent of the pebrine disease, Nosema bombycis, in several insect cell lines. We observed KOH-treated spores and cold-storaged spores can be easily uptaken by all the studied cell types 4 h post inoculation. In contrast, large numbers of freshly recovered spores remained in the culture medium. To further investigate the intracellular fates of KOH-treated spores and cold-storaged spores, electron and fluorescence microscopy were performed. No intracellular germination or subsequent parasite development were observed. Intracellular spores can be detected in host cells by polyclonal antibody 7 d post inoculation, suggesting phagocytized N. bombycis could not be digested by these non-professional phagocytes. Our results suggest that, phagocytic uptake of N. bombycis spores might represent a defense mechanism of the host cells and the intact spore wall barrier enable freshly recovered spores to keep resistance to this mechanism.展开更多
Objective:To evaluate the anti-microsporidial effects of the active component of Nigella sativa seeds,thymoquinone,against Encephalitozoon intestinalis using an in vitro model.Methods:Anti-microsporidial effect of thy...Objective:To evaluate the anti-microsporidial effects of the active component of Nigella sativa seeds,thymoquinone,against Encephalitozoon intestinalis using an in vitro model.Methods:Anti-microsporidial effect of thymoquinone against Encephalitozoon intestinalis was evaluated by using various concentrations of thymoquinone(0,1,5,10,15,20,30,35,and 40μM)and sterile dimethyl sulfoxide.Real time PCR was used to evaluate the inhibitory effects of thymoquinone on the life cycle of Encephalitozoon intestinalis.Results:The cytotoxic effect of thymoquinone on HEK293 cell line was observed with 30,35,and 40μM concentrations of thymoquinone after 24,48,and 72 hours of incubation.It was observed that 10,15,20,and 30μM concentrations of thymoquinone decreased the spore density compared with the control;however,it was significant only at 30μM.Conclusions:Thymoquinone shows potent anti-microsporidial effects against Encephalitozoon intestinalis in the in vitro model;however,the toxic concentrations of thymoquinone are also toxic to the host cells.展开更多
Microsporidia are a group of intracelluar eukaryotic parasites,which can infected almost all animals,including human beings.Till now,no mitochodria but mitosome,a remnant of mitochondria was discovered in this phylum....Microsporidia are a group of intracelluar eukaryotic parasites,which can infected almost all animals,including human beings.Till now,no mitochodria but mitosome,a remnant of mitochondria was discovered in this phylum.We present here the mitochondrial pyruvate dehydrogenase E1(PDH,including PDHα and PDHβ)of the microsporidian Nosema bombycis,the pathogen of silkworm pébrine.Compared with PDH of microsporidian Encephalitozoon cuniculi and Antonospora locustae,both subunits are conserved.The phylogeny indicated that both subunits are mitochondrial.The syntenic maps revealed the subunits organization of NbPDH is distributed in different scaffolds,similar to that of EcPDH but different with AlPDH,and the relationship between phylogeny tree and organization of PDH suggest that the AlPDH subunits organization is the ancestral style of microsporidia,and through the genome evolution,the reshuffling of the chromosome of microsporidia occurred,the adjacent style of ALPDHE1 organization changed,and the two subunits separated and located to different chromosomes in E.cuniculi.For N.bombycis and N.ceranae,they locate to different scaffolds.In order to determine NbPDH subcellular localizations,we prepared the polyclonal antibodies against NbPDH prokaryotic fusion proteins,and adopted the colloidal gold immunological electron microscopy,the expression signals of NbPDH were observed in spores however,the subcellular localization were not definited.In general,through comparison of three microsporidian PDH molecular phylogeny,subunits organization in chromosomes,localization indicated that PDH is an interesting marker in microsporidia evolution.展开更多
Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity a...Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most （even if closely related） remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis： microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.展开更多
Invasive alien species, such as the multicoloured Asian ladybird Harmonia axyridis, are often regarded as major drivers ofbiodiversity loss. Therefore understanding which characteristics or mechanisms contribute to th...Invasive alien species, such as the multicoloured Asian ladybird Harmonia axyridis, are often regarded as major drivers ofbiodiversity loss. Therefore understanding which characteristics or mechanisms contribute to their invasive success is important. Here the role of symbiotic microsporidia in the hemolymph of H. axyridis was investigated in the context of intraguild predation between wild-caught H. axyridis and the native ladybird species Coccinella septempunctata. The microsporidia were recently discussed to contribute to the unpalatability of Harmonia for other coccinellids during intraguild predation and to function as ＂biological weapons＂. In the present study, visual detection of microsporidia in hemolymph samples revealed that 73.5 % of H. axyridis were infected. Intraguild predation experiments between larvae of the two species showed a significant competitive advantage for H. axyridis, even against larger larvae of C. septempunctata. Adult C. septempunctata always killed and fed on H. axyridis larvae. However only 11.4 % （4 of 47） of C. septempunctata that fed on infected H. axyridis died within 4 months. In contrast to previous studies this suggests that microsporidia or harmonine, the chemical defense compound of H. axyridis, do not lead to death of C. septempunctata preying on larvae ofH. axyridis. Instead our results support the idea that competitive advantage during intraguild predation greatly facilitates the success of H. axyridis and that this may help this highly invasive species to outcompete native species. The impact of microsporidia on Harmonia itself as well as on interspecific interactions require further studies.展开更多
Endoreticulatus bombycis is a new pathogenic microspordia isolated from the silkworm larvae. With polymerase chain reaction (PCR) method,we amplified a fragment of the core sequence of the small subunit ribosomal RNA ...Endoreticulatus bombycis is a new pathogenic microspordia isolated from the silkworm larvae. With polymerase chain reaction (PCR) method,we amplified a fragment of the core sequence of the small subunit ribosomal RNA (SSUrRNA) of Endoreticulatus bombycis. The SSUrRNA fragment was inserted into pMD18-T Vector and then cloned. It had a length of 1 230 nucleotides and a percentage GC content of 51.3%. The accession number in GenBank is gi11181769|AY009115. The secondary structure model of the SSUrRNA of Endoreticulatus bombycis was constructed both on the bases of the sequence alignment and RNAFOLD program of the PC-GENE package. The secondary structure model revealed that Endoreticulatus bombycis lacked many eukaryotic helices, such as helix10, helix 11, helix 18, helix 43 and helix 46,but it has V4 region and has more of prokaryotic character. Analyzed by Blast, Endoreticulatus bombycis, Endoreticulatus schubergi and Pleistophora sp.(Sd-Nu-IW8201) have a high similarity, over 98%. Phylogeny tree of Endoreticulatus and Pleistophora species showed that Endoreticulatus and Pleistophora sp.(Sd-Nu-IW8201) was in a group and the other Pleistophora species were in another group .展开更多
微孢子虫(microsporidia)是一类细胞内专性寄生的单细胞真核生物,虽然分子生物学的研究证据表明其与真菌(fun-gi)存在亲缘关系,但这些证据均是基于单个或少数几个基因构建系统进化树而得出的。利用家蚕微孢子虫全基因组数据,采用基于基...微孢子虫(microsporidia)是一类细胞内专性寄生的单细胞真核生物,虽然分子生物学的研究证据表明其与真菌(fun-gi)存在亲缘关系,但这些证据均是基于单个或少数几个基因构建系统进化树而得出的。利用家蚕微孢子虫全基因组数据,采用基于基因同源性的Darkhorse基因组统计方法,鉴定家蚕微孢子虫基因组中每个基因的来源谱系,并通过全基因组谱系可能性指数(lineage probability index,LPI)分析微孢子虫与其他物种的亲缘关系。结果表明家蚕微孢子虫与其他微孢子虫的LPI加权平均值为0.93,具有最近的亲缘关系,与真菌界的LPI加权平均值为0.65,与原生生物界的LPI加权平均值为0.38。由此证明微孢子虫与真菌存在着更近的亲缘关系,微孢子虫门属于真菌界而非原生生物界。展开更多
基金supported by the National Natural Science Foundation of China (30771456)
文摘Microsporidia are highly specialized obligate intracellular parasites that can infect a wide variety of animals ranging from protists to mammals. The classical concept of the parasite invasion into a host cell involves its polar tube acting as a needle-syringe system. However, recent studies show microsporidian spores can also gain access to host cells by phagocytosis. The present study investigated the phagocytic uptake process of causative agent of the pebrine disease, Nosema bombycis, in several insect cell lines. We observed KOH-treated spores and cold-storaged spores can be easily uptaken by all the studied cell types 4 h post inoculation. In contrast, large numbers of freshly recovered spores remained in the culture medium. To further investigate the intracellular fates of KOH-treated spores and cold-storaged spores, electron and fluorescence microscopy were performed. No intracellular germination or subsequent parasite development were observed. Intracellular spores can be detected in host cells by polyclonal antibody 7 d post inoculation, suggesting phagocytized N. bombycis could not be digested by these non-professional phagocytes. Our results suggest that, phagocytic uptake of N. bombycis spores might represent a defense mechanism of the host cells and the intact spore wall barrier enable freshly recovered spores to keep resistance to this mechanism.
文摘Objective:To evaluate the anti-microsporidial effects of the active component of Nigella sativa seeds,thymoquinone,against Encephalitozoon intestinalis using an in vitro model.Methods:Anti-microsporidial effect of thymoquinone against Encephalitozoon intestinalis was evaluated by using various concentrations of thymoquinone(0,1,5,10,15,20,30,35,and 40μM)and sterile dimethyl sulfoxide.Real time PCR was used to evaluate the inhibitory effects of thymoquinone on the life cycle of Encephalitozoon intestinalis.Results:The cytotoxic effect of thymoquinone on HEK293 cell line was observed with 30,35,and 40μM concentrations of thymoquinone after 24,48,and 72 hours of incubation.It was observed that 10,15,20,and 30μM concentrations of thymoquinone decreased the spore density compared with the control;however,it was significant only at 30μM.Conclusions:Thymoquinone shows potent anti-microsporidial effects against Encephalitozoon intestinalis in the in vitro model;however,the toxic concentrations of thymoquinone are also toxic to the host cells.
基金supported by the Project of Chongqing Science and Technology Commission(CSTC,2006AA5019)National Basic Research Program of China under the grant No.2005CB121000
文摘Microsporidia are a group of intracelluar eukaryotic parasites,which can infected almost all animals,including human beings.Till now,no mitochodria but mitosome,a remnant of mitochondria was discovered in this phylum.We present here the mitochondrial pyruvate dehydrogenase E1(PDH,including PDHα and PDHβ)of the microsporidian Nosema bombycis,the pathogen of silkworm pébrine.Compared with PDH of microsporidian Encephalitozoon cuniculi and Antonospora locustae,both subunits are conserved.The phylogeny indicated that both subunits are mitochondrial.The syntenic maps revealed the subunits organization of NbPDH is distributed in different scaffolds,similar to that of EcPDH but different with AlPDH,and the relationship between phylogeny tree and organization of PDH suggest that the AlPDH subunits organization is the ancestral style of microsporidia,and through the genome evolution,the reshuffling of the chromosome of microsporidia occurred,the adjacent style of ALPDHE1 organization changed,and the two subunits separated and located to different chromosomes in E.cuniculi.For N.bombycis and N.ceranae,they locate to different scaffolds.In order to determine NbPDH subcellular localizations,we prepared the polyclonal antibodies against NbPDH prokaryotic fusion proteins,and adopted the colloidal gold immunological electron microscopy,the expression signals of NbPDH were observed in spores however,the subcellular localization were not definited.In general,through comparison of three microsporidian PDH molecular phylogeny,subunits organization in chromosomes,localization indicated that PDH is an interesting marker in microsporidia evolution.
文摘Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most （even if closely related） remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis： microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.
文摘Invasive alien species, such as the multicoloured Asian ladybird Harmonia axyridis, are often regarded as major drivers ofbiodiversity loss. Therefore understanding which characteristics or mechanisms contribute to their invasive success is important. Here the role of symbiotic microsporidia in the hemolymph of H. axyridis was investigated in the context of intraguild predation between wild-caught H. axyridis and the native ladybird species Coccinella septempunctata. The microsporidia were recently discussed to contribute to the unpalatability of Harmonia for other coccinellids during intraguild predation and to function as ＂biological weapons＂. In the present study, visual detection of microsporidia in hemolymph samples revealed that 73.5 % of H. axyridis were infected. Intraguild predation experiments between larvae of the two species showed a significant competitive advantage for H. axyridis, even against larger larvae of C. septempunctata. Adult C. septempunctata always killed and fed on H. axyridis larvae. However only 11.4 % （4 of 47） of C. septempunctata that fed on infected H. axyridis died within 4 months. In contrast to previous studies this suggests that microsporidia or harmonine, the chemical defense compound of H. axyridis, do not lead to death of C. septempunctata preying on larvae ofH. axyridis. Instead our results support the idea that competitive advantage during intraguild predation greatly facilitates the success of H. axyridis and that this may help this highly invasive species to outcompete native species. The impact of microsporidia on Harmonia itself as well as on interspecific interactions require further studies.
文摘Endoreticulatus bombycis is a new pathogenic microspordia isolated from the silkworm larvae. With polymerase chain reaction (PCR) method,we amplified a fragment of the core sequence of the small subunit ribosomal RNA (SSUrRNA) of Endoreticulatus bombycis. The SSUrRNA fragment was inserted into pMD18-T Vector and then cloned. It had a length of 1 230 nucleotides and a percentage GC content of 51.3%. The accession number in GenBank is gi11181769|AY009115. The secondary structure model of the SSUrRNA of Endoreticulatus bombycis was constructed both on the bases of the sequence alignment and RNAFOLD program of the PC-GENE package. The secondary structure model revealed that Endoreticulatus bombycis lacked many eukaryotic helices, such as helix10, helix 11, helix 18, helix 43 and helix 46,but it has V4 region and has more of prokaryotic character. Analyzed by Blast, Endoreticulatus bombycis, Endoreticulatus schubergi and Pleistophora sp.(Sd-Nu-IW8201) have a high similarity, over 98%. Phylogeny tree of Endoreticulatus and Pleistophora species showed that Endoreticulatus and Pleistophora sp.(Sd-Nu-IW8201) was in a group and the other Pleistophora species were in another group .
文摘微孢子虫(microsporidia)是一类细胞内专性寄生的单细胞真核生物,虽然分子生物学的研究证据表明其与真菌(fun-gi)存在亲缘关系,但这些证据均是基于单个或少数几个基因构建系统进化树而得出的。利用家蚕微孢子虫全基因组数据,采用基于基因同源性的Darkhorse基因组统计方法,鉴定家蚕微孢子虫基因组中每个基因的来源谱系,并通过全基因组谱系可能性指数(lineage probability index,LPI)分析微孢子虫与其他物种的亲缘关系。结果表明家蚕微孢子虫与其他微孢子虫的LPI加权平均值为0.93,具有最近的亲缘关系,与真菌界的LPI加权平均值为0.65,与原生生物界的LPI加权平均值为0.38。由此证明微孢子虫与真菌存在着更近的亲缘关系,微孢子虫门属于真菌界而非原生生物界。
