The social amoeba Polysphondylium pallidum loses encystation and sporulation, but can still erect fruiting bodies in the absence of cellulose.
The social amoeba Polysphondylium pallidum loses encystation and sporulation, but can still erect fruiting bodies in the absence of cellulose.
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DOI：
10.1016/j.protis.2014.07.003
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发表时间：
2014-09
期刊：
影响因子：
2.5
通讯作者：
Schaap, Pauline
中科院分区：
文献类型：
--
作者：
Du, Qingyou;Schaap, Pauline
关键词：
变形虫和其他自由移动的原生生物在受到压力时会分化成有壁的包囊。作为包囊，阿米巴病原体对杀生物剂具有抗性，从而妨碍治疗和根除。由于缺乏基因修饰程序，包囊形成的机制在很大程度上尚未探索。遗传上易处理的盘基网柄菌变形虫需要纤维素合成酶来形成具有富含纤维素的柄细胞和孢子细胞的多细胞果实。变形虫的远亲苍白多软骨藻（Ppal），可以额外encyst单独响应压力。Ppal有两个纤维素合成酶基因，DcsA和DcsB，我们单独和组合删除。Dcsa突变体形成子实体与正常的柄，但他们的孢子和孢囊壁缺乏纤维素，这抹杀了孢子的抗逆性，使孢囊完全不能生存。一个dcsa-/dcsb-突变体没有壁孢子，柄细胞或孢囊，虽然简单的果结构形成了一滴变形虫细胞休息的鞘柱腐烂的细胞。DcsB在前柄和柄细胞中表达，而DcsA另外在孢子和孢囊中表达。我们的结论是，纤维素是必不可少的包囊和纤维素合成酶可能是一个合适的药物，以防止包囊和使阿米巴病原体对传统抗生素敏感的目标。
Amoebas and other freely moving protists differentiate into walled cysts when exposed to stress. As cysts, amoeba pathogens are resistant to biocides, preventing treatment and eradication. Lack of gene modification procedures has left the mechanisms of encystation largely unexplored. Genetically tractable Dictyostelium discoideum amoebas require cellulose synthase for formation of multicellular fructifications with cellulose-rich stalk and spore cells. Amoebas of its distant relative Polysphondylium pallidum (Ppal), can additionally encyst individually in response to stress. Ppal has two cellulose synthase genes, DcsA and DcsB, which we deleted individually and in combination. Dcsa- mutants formed fruiting bodies with normal stalks, but their spore and cyst walls lacked cellulose, which obliterated stress-resistance of spores and rendered cysts entirely non-viable. A dcsa-/dcsb- mutant made no walled spores, stalk cells or cysts, although simple fruiting structures were formed with a droplet of amoeboid cells resting on an sheathed column of decaying cells. DcsB is expressed in prestalk and stalk cells, while DcsA is additionally expressed in spores and cysts. We conclude that cellulose is essential for encystation and that cellulose synthase may be a suitable target for drugs to prevent encystation and render amoeba pathogens susceptible to conventional antibiotics.
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DOI：
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发表时间：
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影响因子：
11.1
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DOI：
10.1073/pnas.0901617106
发表时间：
2009-04-28
影响因子：
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作者：
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通讯作者：
Schaap, Pauline