Introduction: A recent study in Kenya highlighted a promising advance in malaria control by demonstrating that infecting mosquitoes with the endosymbiont Microsporidia MB blocks Plasmodium transmission. However, the i...Introduction: A recent study in Kenya highlighted a promising advance in malaria control by demonstrating that infecting mosquitoes with the endosymbiont Microsporidia MB blocks Plasmodium transmission. However, the influence of biotic and abiotic factors such as diet, relative humidity (RH) and temperature on this infection remains poorly studied. This study, aimed to gain a better understanding of this relationship. Methods: To highlight the influence of diet quantity, we defined a range of 3 quantities: 0.00375 g, 0.015 g and 0.09 g. Each quantity was tested on two groups of larvae: a group of 150 larvae infected with Microsporidia MB (MB+), and a group of 150 larvae not infected with Microsporidia MB (MB−) (control group), each divided into three replicates of 50 larvae. Each replicate was fed each morning with the assigned quantity until the pupal stage. In addition to this factor, we investigated the influence of temperature and RH. We defined three temperature-RH combinations: 21˚C-80% RH, 39˚C-50% RH, and 27˚C-75% RH. Each combination was tested on two groups of larvae: a group of 150 MB+ larvae and a group of 150 MB− larvae, each divided into three replicates of 50 larvae. Each replicate was subjected to the assigned combination until pupation. Pupae that had reached the adult stage were tested by PCR to determine their Microsporidia MB infection status for each factor studied. Results: The results showed that only the lowest quantity (0.00375 g) significantly reduced the prevalence of Microsporidia MB compared with the medium quantity (chi-2 test, χ2 = 4.9088, df = 1, p = 0.02672) and the high quantity (chi-2 test, χ2 = 4.7958, df = 1, p = 0.02853). As for temperature and RH, the combination 39˚C-50% RH led to a significant reduction in the prevalence of Microsporidia MB compared with the combination 27˚C-75% RH (chi-2 test, χ2 = 6.3736, ddl = 1, p = 0.01158) and that 21˚C-80% RH (chi-2 test, χ2 = 9.983, ddl = 1, p = 0.00158). Conclusion: This work contributes to a better understanding of some key factors linked to Microsporidia MB infection in mosquitoes. However, further research on several generations is necessary to draw more comprehensive conclusions.展开更多
Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide ...Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide resistance in vectors undermine the fight against vectors. Endonsymbiotic fungi can be a good candidate to include in the existence of Arsenal. However, we know little about endosymbiotic fungi transmission and its impact on malaria transmission. In this paper, the authors aimed to investigate Microsporidia sp MB transgenerational and sexual autodissemination and malaria parasites within Anopheline mosquitoes. Methods: An entomology survey was conducted in Burkina Faso for one year (June 2020 to June 2021) using the Residual Fauna Capture method. Infection rates in collected females, sexual autodissemination of Microsporidia sp MB in both Microsporidia sp MB negative females and Microsporidia sp MB negative males through mating, transgenerational prevalence from parents to offsprings and the correlation between Microsporidia sp MB and Plasmodium falciparum were investigated. Results: Results show Microsporidia sp MB infection in An. gambaie s.l in Burkina Faso. The prevalence was significantly higher (21.78%) in An. coluzzii than An. gambiae s.s (16.89%) (p-value = 0.03). Sexual auto-dissemination of Microsporidia sp MB in Microsporidia sp MB uninfected females was significantly 3-fold lower than those in Microsporidia sp MB uninfected males (9.23% and 33.33%, p-value = 0.03) during mating for An. coluzzii lines. Microsporidia sp MB prevalence was significantly higher through mosquitos’ generations in An. gambaie s.s than An. coluzzii (30.23% vs 26.41%, p-value Microsporidia sp MB and Plasmodium infection rate with 73% of Microsporidia sp MB positive mosquitoes which were negative at Plasmodium infection (p-value Conclusions: Our findings pave the road to developing new malaria control technologies by making Microsporidia sp MB-positive males sexually competitive with wild males to spread the fungus to wild female mosquitoes.展开更多
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
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 ph...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 El （PDH, including PDHα and PDHβ） of the microsporidian Nosema bombycis, the pathogen of silkworm pebrine. Compared with PDH of microsporidian Encephalitozoon cuniculi and Antonospora locustae, both subunits are eonscrced. 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 AIPDH, 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 mierosporidian PDH molecular phylogeny, subunits organization in chromosomes, localization indicated that PDH is an interesting marker in microsporidia evolution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
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
文摘Introduction: A recent study in Kenya highlighted a promising advance in malaria control by demonstrating that infecting mosquitoes with the endosymbiont Microsporidia MB blocks Plasmodium transmission. However, the influence of biotic and abiotic factors such as diet, relative humidity (RH) and temperature on this infection remains poorly studied. This study, aimed to gain a better understanding of this relationship. Methods: To highlight the influence of diet quantity, we defined a range of 3 quantities: 0.00375 g, 0.015 g and 0.09 g. Each quantity was tested on two groups of larvae: a group of 150 larvae infected with Microsporidia MB (MB+), and a group of 150 larvae not infected with Microsporidia MB (MB−) (control group), each divided into three replicates of 50 larvae. Each replicate was fed each morning with the assigned quantity until the pupal stage. In addition to this factor, we investigated the influence of temperature and RH. We defined three temperature-RH combinations: 21˚C-80% RH, 39˚C-50% RH, and 27˚C-75% RH. Each combination was tested on two groups of larvae: a group of 150 MB+ larvae and a group of 150 MB− larvae, each divided into three replicates of 50 larvae. Each replicate was subjected to the assigned combination until pupation. Pupae that had reached the adult stage were tested by PCR to determine their Microsporidia MB infection status for each factor studied. Results: The results showed that only the lowest quantity (0.00375 g) significantly reduced the prevalence of Microsporidia MB compared with the medium quantity (chi-2 test, χ2 = 4.9088, df = 1, p = 0.02672) and the high quantity (chi-2 test, χ2 = 4.7958, df = 1, p = 0.02853). As for temperature and RH, the combination 39˚C-50% RH led to a significant reduction in the prevalence of Microsporidia MB compared with the combination 27˚C-75% RH (chi-2 test, χ2 = 6.3736, ddl = 1, p = 0.01158) and that 21˚C-80% RH (chi-2 test, χ2 = 9.983, ddl = 1, p = 0.00158). Conclusion: This work contributes to a better understanding of some key factors linked to Microsporidia MB infection in mosquitoes. However, further research on several generations is necessary to draw more comprehensive conclusions.
文摘Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide resistance in vectors undermine the fight against vectors. Endonsymbiotic fungi can be a good candidate to include in the existence of Arsenal. However, we know little about endosymbiotic fungi transmission and its impact on malaria transmission. In this paper, the authors aimed to investigate Microsporidia sp MB transgenerational and sexual autodissemination and malaria parasites within Anopheline mosquitoes. Methods: An entomology survey was conducted in Burkina Faso for one year (June 2020 to June 2021) using the Residual Fauna Capture method. Infection rates in collected females, sexual autodissemination of Microsporidia sp MB in both Microsporidia sp MB negative females and Microsporidia sp MB negative males through mating, transgenerational prevalence from parents to offsprings and the correlation between Microsporidia sp MB and Plasmodium falciparum were investigated. Results: Results show Microsporidia sp MB infection in An. gambaie s.l in Burkina Faso. The prevalence was significantly higher (21.78%) in An. coluzzii than An. gambiae s.s (16.89%) (p-value = 0.03). Sexual auto-dissemination of Microsporidia sp MB in Microsporidia sp MB uninfected females was significantly 3-fold lower than those in Microsporidia sp MB uninfected males (9.23% and 33.33%, p-value = 0.03) during mating for An. coluzzii lines. Microsporidia sp MB prevalence was significantly higher through mosquitos’ generations in An. gambaie s.s than An. coluzzii (30.23% vs 26.41%, p-value Microsporidia sp MB and Plasmodium infection rate with 73% of Microsporidia sp MB positive mosquitoes which were negative at Plasmodium infection (p-value Conclusions: Our findings pave the road to developing new malaria control technologies by making Microsporidia sp MB-positive males sexually competitive with wild males to spread the fungus to wild female mosquitoes.
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.
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 El （PDH, including PDHα and PDHβ） of the microsporidian Nosema bombycis, the pathogen of silkworm pebrine. Compared with PDH of microsporidian Encephalitozoon cuniculi and Antonospora locustae, both subunits are eonscrced. 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 AIPDH, 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 mierosporidian PDH molecular phylogeny, subunits organization in chromosomes, localization indicated that PDH is an interesting marker in microsporidia evolution
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.
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.
