Maor-Landaw Keren, Smirnov Margarita, Brekhman Vera, Ofek-Lalzar Maya, Yahav Tal, Lotan Tamar
Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3498838, Israel.
Central Fish Health Laboratory, Department of Fisheries and Aquaculture, Ministry of Agriculture and Rural Development, Nir David 10803, Israel.
Microorganisms. 2022 Sep 23;10(10):1893. doi: 10.3390/microorganisms10101893.
Myxozoa (Cnidaria) is a large group of microscopic obligate endoparasites that can cause emerging diseases, affecting wild fish populations and fisheries. Recently, the myxozoan was found to infect the gills of hybrid tilapia (Nile tilapia () × Jordan/blue tilapia ()), causing high morbidity and mortality. Here, we used comparative transcriptomics to elucidate the molecular processes occurring in the fish host following infection by . Fish were exposed to pond water containing actinospores for 24 h and the effects of minor, intermediate, and severe infections on the sporulation site, the gills, and on the hematopoietic organs, head kidney and spleen, were compared. Enrichment analysis for GO and KEGG pathways indicated immune system activation in gills at severe infection, whereas in the head kidney a broad immune suppression included deactivation of cytokines and GATA3 transcription factor responsible for T helper cell differentiation. In the spleen, the cytotoxic effector proteins perforin and granzyme B were downregulated and insulin, which may function as an immunomodulatory hormone inducing systemic immune suppression, was upregulated. These findings suggest that is a highly efficient parasite that disables the defense mechanisms of its fish host hybrid tilapia.
粘孢子虫（刺胞动物门）是一大类微观专性内寄生虫，可引发新出现的疾病，影响野生鱼类种群和渔业。最近，发现这种粘孢子虫感染了杂交罗非鱼（尼罗罗非鱼（）×约旦/蓝罗非鱼（））的鳃，导致高发病率和死亡率。在此，我们使用比较转录组学来阐明鱼类宿主在被感染后发生的分子过程。将鱼暴露于含有放线孢子的池塘水中24小时，比较轻度、中度和重度感染对孢子形成部位、鳃以及造血器官（头肾和脾脏）的影响。基因本体（GO）和京都基因与基因组百科全书（KEGG）通路的富集分析表明，重度感染时鳃中的免疫系统被激活，而在头肾中则出现广泛的免疫抑制，包括细胞因子和负责辅助性T细胞分化的GATA3转录因子失活。在脾脏中，细胞毒性效应蛋白穿孔素和颗粒酶B下调，而可能作为诱导全身免疫抑制的免疫调节激素的胰岛素上调。这些发现表明，是一种高效的寄生虫，能够破坏其鱼类宿主杂交罗非鱼的防御机制。
