弓形虫病是由刚地弓形虫引起的人兽共患寄生虫病，速殖子与缓殖子的相互转换是致病的生物学基础。缓殖子时期支链淀粉大量聚集且支链淀粉的变化会导致脑包囊数量明显减少，表明支链淀粉对缓殖子发育极为重要。α-AMY1是支链淀粉分解过程中的关键酶且在缓殖子时期表达明显上调，但是对弓形虫α-AMY1如何调控支链淀粉的分解以及缓殖子发育尚不清楚。因此，本项目以缓殖子时期支链淀粉大量聚集为出发点，对弓形虫α-AMY1进行遗传编辑；对过表达弓形虫α-AMY1的蛋白进行纯化，SPRi分析其有效抑制剂并作用于CDPK2敲除虫株，明确α-AMY1与CDPK2调控支链淀粉的关系；对弓形虫α-AMY1敲除株/互补株进行体内外生物学功能研究，检测弓形虫的支链淀粉及小鼠感染时脑包囊数量变化等，明确α-AMY1调控支链淀粉分解及缓殖子发育的功能。预期结果将为阐明弓形虫速殖子与缓殖子的转换、研发抗缓殖子药物奠定理论基础。

Toxoplasmosis caused by the Toxoplasma gondii infecting most nucleated cells is one of the most common parasitic zoonoses worldwide. The interconversion between tachyzoites and bradyzoites is the biological basis of pathogenesis. A characterisitc of T. gondii bradyzoite presents amylopectin granules, and altered amylopectin digestion results in the reduction of brain cyst numbers. This indicates that amylopectin store plays key roles for the development of bradyzoites. α-amylase (α-AMY1) is a pivotal enzyme in the digestion of amylopectin process, and has a high transcription in the bradyzoites. However, it is yet to know the mechanisms in regard to the regulation of amylopectin digestion and the development of bradyzoites. Thus, this study will focus on the amylopectin accumulation in the bradyzoites, and analyse the functional characteristics of Toxoplasma gondii α-AMY1 based on the CRISPR/Cas9 genome editing. The recombinant α-AMY1 protein will be purified from the ptubTgα-AMY1 strain by anti-flag affinity gel, then inhibitors will be screened by SPRi and applied to the CDPK2 knockout strain. It will elucidate the interaction between α-AMY1 and CDPK2 in the regulation of amylopectin. The biological function of T. gondii α-AMY1 knockout and complement parasites will be analyzed in vivo and in vitro, including detecting the amylopectin in the parasites and counting the brain cyst numbers. It will elucidate the function of α-AMY1 in the regulation of amylopectin digestion and development of bradyzoites. Together, these results will lay a foundation for elucidating the inteconversion between tachyzoites and bradyzoites, and for developing effective drugs against bradyzoites.