中国鲎变形细胞超微结构的进一步观察

FURTHER OBSERVATIONS ON THE ULTRASTRUCTURE OF AMOEBOCYTES OF THE HORSESHOE CRAB, TACHYPLEUS TRIDENTATUS LEACH

中国鲎的变形细胞可在血液中发育成熟,根据其超微结构,可分为原始变形细胞、幼变形细胞和变形细胞三个阶段。 变形细胞受到外环境或内毒素的刺激后,第一型颗粒出现一系列变化,最终把内容物释放到细胞外。与此同时,细胞表面形成若干胞质性突起,边缘带分散断裂,质膜下和胞质性突起中出现微丝。第二型颗粒无变化,提示它们和血液凝胶化过程无直接关系。

In an earlier paper the author had studied the amoebocytes ef the horseshoe crab, Tachypleus tridentatus Leach, with electron microscope to reveal their ultrastructure, including a new type of granules, the type 2 granules. This present paper is a follow-up of the previous work, and reports herewith the results on the ultrastrueture of the amoebocytes taken from the normal blood, the anticoagulated blood and the anticoagu-lated blood before exposed to O111 B4 endotoxin.1. So far, the origin, development, and site of production of the amoebocytes haven't been clarified. We found a small number of immature and maturing amoebocytes in the circulating blood, some being in mitosis. This finding suggests that at least some amoebocytes could differentiate and mature in the circulating blood. The author proposes that the development of an amoebocyte could be divided into three stages, namely amoeboblast, proamoebocyte and amoebocyte.2. In the amoebocytes activited by endotoxin or certain exogenous factors, the type 1 granules underwent a series of changes including swelling, appearance of subu-nits within granular contents, fusion of limiting membrane, with plasma membrane, and release of their contents by exocytosis. Because the subunits always appear within the contents in newly formed granules, it was suspected that they may represent an integral part of the granular contents, which couldn't be recognized as the granule came to maturity. Their reappearance may be a necessary step towards exocytosis.3. During the development of amoebocytes the type 2 granules make their appearance much earlier than that of type 1 granules. Type 2 granules didn't show any ultrastruetural change after the cell had been activated, suggesting that they have no relation to the clotting process. Occasionally type 2 granules were seen to be enclosed within some vaeuoles of double-layered limiting membrane, therefore their participation in the a,utophagic process, as well as their lysosomal nature, should be suspected.4. Both microtubules and microfilaments showed a series of changes during the activation of amoebocytes. It was speculated that the chief component of microfilament may be aetin.