Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, China.
Department of Biology, Hamilton College, Clinton, New York, United States of America.
PLoS One. 2020 Aug 28;15(8):e0238167. doi: 10.1371/journal.pone.0238167. eCollection 2020.
The ciliated protozoan Cryptocaryon irritans infects a wide range of marine fish and causes the highly lethal white spot disease. This parasite possesses three morphologically and physiologically distinct life stages: an infectious theront, a parasitic trophont, and an asexually reproductive tomont. In the past few years, several attempts have been made to help elucidate how C. irritans transforms from one stage to another using transcriptomic or proteomic approaches. However, there has been no research studying changes in transcription profiles between different time points of a single C. irritans life stage-the development of this parasite. Here we use RNA-seq and compare gene expression profiles of theront cells collected by 1 and 10 hrs after they emerged from tomonts. It has been shown that infectivity of theront cells declines 6-8 hours post-emergence, and we used this characteristic as a physiological marker to confirm the aging of theront cells. We identified a total of 41 upregulated and 90 downregulated genes that were differentially expressed between young and aging theront cells. Using Blast2Go to further analyze functions of these genes, we show that genes related to energy production are downregulated, but quite surprisingly many genes involved in transcription/translation processes are upregulated. We also show that expression of all nine detectable agglutination/immobilization antigen genes, with great sequence divergence, is invariably downregulated. Functions of other differentially expressed genes and indications are also discussed in our study.
纤毛原生动物 Cryptocaryon irritans 感染了广泛的海洋鱼类，并导致高度致命的白点病。这种寄生虫具有三种形态和生理上明显不同的生命阶段：传染性游仆虫、寄生滋养体和无性繁殖的裂殖体。在过去的几年中，人们已经尝试使用转录组学或蛋白质组学方法来帮助阐明 C. irritans 如何从一个阶段转变为另一个阶段。然而，还没有研究研究单个 C. irritans 生命阶段（寄生虫的发育）的不同时间点之间转录谱的变化。在这里，我们使用 RNA-seq 并比较了从裂殖体中出现后 1 小时和 10 小时收集的游仆虫细胞的基因表达谱。已经表明，游仆虫细胞的感染力在出现后 6-8 小时下降，我们使用这个特征作为生理标记来确认游仆虫细胞的老化。我们总共鉴定了 41 个上调和 90 个下调的基因，这些基因在年轻和老化的游仆虫细胞之间差异表达。使用 Blast2Go 进一步分析这些基因的功能，我们表明与能量产生相关的基因下调，但令人惊讶的是，许多与转录/翻译过程相关的基因上调。我们还表明，所有九个可检测的凝集/固定抗原基因的表达，具有很大的序列差异，始终下调。我们还讨论了其他差异表达基因的功能和指示。
