PARASITOLOGY RESEARCH
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2019
·Vol. 118
·期 3
·935-944
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IF 2.067
Ye Shu,Xia Ningbo,Zhao Pengfei,Yang Jichao,Zhou Yanqin,Shen Bang,Zhao Junlong
Toxoplasma gondii is a ubiquitous parasitic protozoan infecting humans and a wide variety of animals. Fast-replicating tachyzoites during acute infection and slowly growing bradyzoites during chronic infection are the two basic forms of T. gondii in intermediate hosts. Interconversion between the two contributes to the transmission and pathogenesis of this parasite. Secretory micronemal proteins are thought to mediate interactions with host cells and facilitate parasite invasion, therefore the majority of them are highly expressed in tachyzoites. Micronemal protein 13 (MIC13) is unique in that its expression is low in tachyzoites and is upregulated under bradyzoite-inducing conditions. Previous attempts to disrupt this gene were not successful, implying that it may play critical roles during parasite growth. However, in this study, MIC13 was successfully disrupted in type 1 strain RH and type 2 strain ME49 using CRISPR/Cas9-mediated gene disruption techniques. Consistent with its low expression in tachyzoites and increased expression under stress or bradyzoite-inducing conditions, MIC13-inactivated mutants displayed normal growth, host cell invasion, intracellular replication, and egress, as well as acute virulence at the tachyzoite stage. However, under stress conditions, such as high pH or oxygen limitation, MIC13-disrupted parasites showed significantly slower growth rates compared to the parental strains, suggesting that it is required for optimal parasite growth under bradyzoite-inducing or stress conditions. This is the first micronemal protein reported to have such expression pattern and function modes, which expands our understanding of the diverse functions of micronemal proteins.
研究领域:
寄生虫学
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分子生物学
·
传染病学
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DOI
PubMed
高影响因子
Parasites & Vectors
·
2025
·Vol. 18
·期 1
·1-15
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IF 3.5
Geng Xiao-Ling,Li Jing-Yu,Xu Huan-Yu,Wu Jiang-Ping,Tao De-Liang,Chen Jin-Ming,Fan Ying-Ying,Yang Xin,Song Jun-Ke,Zhao Guang-Hui
Background The pathogenicity of Toxoplasma gondii is closely associated with its intracellular lytic cycle in host cells. Currently, the mechanisms by which T. gondii completes the lytic cycle remain unclear. The proline metabolism has been reported to be crucial for intracellular growth of pathogens by providing energy and nutrients. However, it remains unclear whether the intracellular growth and pathogenicity of T. gondii are related to proline metabolism.Methods The gene-edited strains of proline dehydrogenase (Tgprodh) were constructed by using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR–Cas9) technology. The effects of the Tgprodh gene on the growth in vitro and pathogenicity in vivo of the tachyzoites for T. gondii were studied through proliferation, plaque, invasion, egress and virulence assays. The effects of the Tgprodh gene on mitochondrial function were studied by using reactive oxygen species (ROS), mitochondrial membrane potential (∆Ψm), adenosine triphosphate (ATP) assay kits, mitochondrial DNA (mtDNA) copy numbers, transmission electron microscopy (TEM) analysis, and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). The effects of the Tgprodh gene on proline metabolism were studied by using l-proline (L-Pro), l-glutamic acid (L-Glu), l-glutamine (L-Gln) assay kits, and RT-qPCR.Results TgPRODH, the first rate-limiting enzyme in proline metabolism, was identified to be encoded by T. gondii and localized in the cytoplasm of T. gondii. Deletion of the Tgprodh gene resulted in significant growth inhibition in vitro and reduced pathogenicity in vivo of T. gondii. Further study found that deletion of the Tgprodh gene caused damage to the mitochondrial morphology, decreased membrane potential, mtDNA copy numbers, and the production of ATP and ROS. The expression of genes for maintaining mitochondrial integrity was downregulated in the Tgprodh-knockout strain of T. gondii, while complementation of the Tgprodh gene restored these defects in this parasite. Meantime, the deletion of the Tgprodh gene resulted in the accumulation of proline, reduced the contents of glutamate and glutamine, and affected the expression of genes related to proline catabolism in T. gondii.Conclusion sThe present study found the significance of the Tgprodh gene for the intracellular growth and pathogenicity of T. gondii through regulating mitochondrial function and the proline metabolism and provided a novel insight to reveal intracellular survival strategies of T. gondii.Graphical
研究领域:
寄生虫学
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微生物学
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分子生物学
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细胞生物学
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遗传学
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生物化学
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产品关联
DOI
PubMed
高影响因子
EXPERIMENTAL PARASITOLOGY
·
2016
·
IF 1.623
Xiaochuan Zhang,Lili Jin,Zhe Cui,Changhao Zhang,Xue Wu,Hyun Park,Hongmei Quan,Chunmei Jin
Toxoplasma gondii ( T . gondii ) is an important pathogen which can causes serious public health problems. Since the current therapeutic drugs for toxoplasmosis present serious host toxicity, research on effective and new substances of relatively low toxicity is urgently needed. This study was carried out to evaluate the anti-parasitic effect of oxymatrine (OM) and matrine (ME) against T . gondii in vitro and in vivo . In our study, the anti- T . gondii activities of ME and OM were evaluated in vitro using cell counting kit-8 assay, morphological observation and trypan blue exclusion assay. In vivo , mice were sacrificed four days post-infection and ascites were drawn out to determine the extent of tachyzoite proliferation. Viscera indexes and liver biochemical parameters, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione (GSH) and malondialdehyde (MDA), were examined to evaluate the toxicity of compounds to mice. As a result, OM and ME showed anti- T . gondii activity but low selectivity toxicity to HeLa cells. Both compounds also significantly decreased the number of tachyzoites in peritoneal cavity and recovered the levels of ALT, AST, GSH and MDA in liver. Moreover, the mice treated with OM or ME achieved better results in viscera index and survival rate than that of spiramycin. These results suggest that OM and ME are likely the sources of new drugs for toxoplasmosis, and further studies will be necessary to compare the efficacy of drug combination, as well as identify its action of mechanism.
研究领域:
寄生虫学
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药理学
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传染病学
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产品关联
DOI
PubMed
高影响因子
MICROBIAL PATHOGENESIS
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2023
·
IF 3.8
Yuxiao Qian,Yuqian Jiang,Hongrong Hong,Xinxin Gao,Wei Liu,Meiyi Chen,Qinqin Jin,Zha Jin,Xin Li,Xiaocen Wang,Jianhua Li,Quan Liu,Xichen Zhang,Nan Zhang,Zhengkai Wei
Pigeons are natural intermediate host of Neospora caninum ( N. caninum ). In comparison to ruminants, N. caninum causes milder clinical symptoms and less financial loss to pigeons. Natural infectious rates and high prevalence of N. caninum in pigeons, and death cases of N. caninum- infected pigeons under experimental conditions have been reported, but the detailed pathological characteristics and congenital immunological responses of pigeons-infected with N. caninum remain not well described. In this study, pigeons were infected intraperitoneally with 10 7 N. caninum tachyzoites . N. caninum in tissues was detected by qPCR. Pathological changes of tissues were examined by hematoxylin-eosin staining. Blood smears were prepared for counting eosinophils changes in blood. Heterophil extracellular traps (HETs) in vivo and in vitro were quantified by Pico Green. N. caninum- induced HETs structures were observed by immunofluorescence staining. The model of pigeons-infected with N. caninum was successfully established. Lung and duodenum were the main target organs of pigeons-infected with N. caninum . N. caninum caused hemorrhage, edema and inflammatory cell infiltration in liver, pulmonary congestion and hemorrhage, organizational destruction in lung, and shorter villi or even disappear in duodenum. N. caninum also increased the number of eosinophils in blood of pigeons. Moreover, N. caninum -induced HETs release in the congenital immunological system of pigeons were first demonstrated, and the HETs structures were consisted of DNA as the skeleton and modified with citH3 and elastase . N. caninum -induced HETs release was related with NADPH oxidase , TLR 2 and 4, ERK 1/2 and p38 MAPK signaling pathways , and glycolysis. In summary, it is the first report on the detailed pathological characteristics and congenital immunological responses of pigeons-infected with N. caninum , which may provide theoretical basis for the prevention and control of Neosporosis in pigeons.
研究领域:
兽医学
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免疫学
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病理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）