Morphological characterization of the tunic in the edible ascidian, Halocynthia roretzi (Drasche), with remarks on 'soft tunic syndrome' in aquaculture
Morphological characterization of the tunic in the edible ascidian, Halocynthia roretzi (Drasche), with remarks on 'soft tunic syndrome' in aquaculture
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DOI：
10.1111/j.1365-2761.2009.01034.x
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发表时间：
2009-05-01
影响因子：
2.5
通讯作者：
Azumi, K.
中科院分区：
文献类型：
--
作者：
Hirose, E.;Ohtake, S-I;Azumi, K.
“软被膜综合征”是可食用海鞘（Halocynthia roretzi（Drasche））水产养殖中的一个严重问题，并且经常导致大规模死亡。在这里，我们描述了被膜形态的完整和患病海鞘揭示它们之间的结构差异。在形态学上，患病的被膜与完整的被膜没有很大的不同，尽管前者比后者更薄更软。虽然几种类型的细胞分布在被膜中，但两组的细胞类型及其细胞形态几乎相同。由于在完整或患病的被膜中均未发现细菌/原生动物细胞，因此它们不是软被膜综合征的直接原因。最显着的差异是在束的被膜纤维组成的被膜矩阵;在完整的被膜，厚束交织形成一个坚定的矩阵，而在软被膜，被膜纤维不形成厚束。此外，在患病的鳞茎中发现了低纤维密度的区域。因此，软被膜综合征可能导致束形成抑制和被膜束降解，形成低纤维密度区域，尽管原因尚不清楚。
'Soft tunic syndrome' is a serious problem in the aquaculture of the edible ascidian, Halocynthia roretzi (Drasche), and often leads to mass mortality. Here, we describe the tunic morphology of intact and diseased ascidians to reveal structural differences between them. Morphologically, diseased tunics are not very different from intact tunics, although the former are thinner and softer than the latter. While several types of cells are distributed in the tunic, the cell types and their cytomorphologies were almost identical in both groups. As bacterial/protozoan cells were not found in either intact or diseased tunics, they are not the direct cause of soft tunic syndrome. The most remarkable difference was in the bundles of tunic fibres that compose the tunic matrix; in intact tunics, the thick bundles interlace to form a firm matrix, whereas in soft tunics, the tunic fibres do not form thick bundles. Furthermore, areas of low fibre density were found in diseased tunics. Therefore, soft tunic syndrome probably causes inhibition of bundle formation and degradation of tunic bundles, creating areas of low fibre density, although the causes remain unknown.