Germ Tube Mediated Invasion of Batrachochytrium dendrobatidis in Amphibian Skin Is Host Dependent
Germ Tube Mediated Invasion of Batrachochytrium dendrobatidis in Amphibian Skin Is Host Dependent
复制标题
两栖动物皮肤中的生殖管介导的 Batrachochytrium dendrobatidis 的入侵是宿主依赖性的
作者：
P. Van Rooij;A. Martel;K. D’Herde;Melanie Brutyn;S. Croubels;R. Ducatelle;F. Haesebrouck;F. Pasmans
树突巴氏杆菌(Batrachochytrium Dendrobatidis，Bd)是一种两栖类真菌皮肤病的病原体，也是世界范围内两栖动物数量下降的驱动力。我们重点研究了Bd在三种两栖动物中感染的早期阶段，这些物种对丝状真菌病有不同的易感性。将毛叶猴、蓝爪哇和非洲爪哇的皮肤外植体暴露于Bd中3~5天。用光学显微镜和透射电子显微镜观察了BD与两栖动物皮肤的早期相互作用。为了在体外验证观察结果，我们与实验感染的青蛙的皮肤进行了比较。此外，还进行了体外实验，以阐明蓝藻在细胞内定植的过程。BD与两栖动物皮肤的早期相互作用是：游动孢子附着在宿主皮肤上，游动孢子萌发，生殖管发育，穿透皮肤细胞，在宿主皮肤侵袭生长，导致宿主细胞细胞质的丧失。接种毛霉菌和蓝乳杆菌皮片后24 h内即有内生生物发育，孢子囊位于细胞内。提供了细胞内定植是如何建立的，以及BD定植如何深入皮肤的证据。较老的叶状体形成根状结构，向更深的皮肤层扩散，在宿主细胞内形成肿胀，最终形成新的叶状体。在X.laevis中，Bd与皮肤的相互作用仅限于共生状态，并在皮肤上形成孢子囊。只有浅表的表皮受到影响。表皮细胞似乎被用作营养来源，不形成细胞内的菌体。体外实验数据与所研究的蛙种实验感染后的结果一致。这些数据表明，树枝杆菌的定植策略依赖于寄主，定植的程度很可能由寄主表皮的固有特征决定。
Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines. We focussed on the early stages of infection by Bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. Skin explants of Alytes muletensis, Litoria caerulea and Xenopus leavis were exposed to Bd in an Ussing chamber for 3 to 5 days. Early interactions of Bd with amphibian skin were observed using light microscopy and transmission electron microscopy. To validate the observations in vitro, comparison was made with skin from experimentally infected frogs. Additional in vitro experiments were performed to elucidate the process of intracellular colonization in L. caerulea. Early interactions of Bd with amphibian skin are: attachment of zoospores to host skin, zoospore germination, germ tube development, penetration into skin cells, invasive growth in the host skin, resulting in the loss of host cell cytoplasm. Inoculation of A. muletensis and L. caerulea skin was followed within 24 h by endobiotic development, with sporangia located intracellularly in the skin. Evidence is provided of how intracellular colonization is established and how colonization by Bd proceeds to deeper skin layers. Older thalli develop rhizoid-like structures that spread to deeper skin layers, form a swelling inside the host cell to finally give rise to a new thallus. In X. laevis, interaction of Bd with skin was limited to an epibiotic state, with sporangia developing upon the skin. Only the superficial epidermis was affected. Epidermal cells seemed to be used as a nutrient source without development of intracellular thalli. The in vitro data agreed with the results obtained after experimental infection of the studied frog species. These data suggest that the colonization strategy of B. dendrobatidis is host dependent, with the extent of colonization most likely determined by inherent characteristics of the host epidermis.
DOI：
10.1073/pnas.1111915108
发表时间：
2011-11-15
影响因子：
11.1
作者：
Farrer, Rhys A.;Weinert, Lucy A.;Fisher, Matthew C.
通讯作者：
Fisher, Matthew C.