| 摘要: |
| 于1993年11月和1994年11月在海南省临高县新盈珍珠贝养殖场采集患病或濒死的大珠母贝幼贝，采用组织切片和扫描电镜技术对其病原类立克次体（Rickettsia-likeorganism，RLO）的包涵体进行组织学和超微结构研究，以期找出RLO包涵体在宿主细胞内形态发生的内在规律。结果表明，RLO包涵体寄生在宿主多处内脏组织，但RLO具有明显的嗜细胞特异性，感染的靶细胞为上皮（或表皮）、结缔组织和血管内皮细胞；包涵体存在不同的发育时期，可分为颗粒前期和颗粒期，后者又可分为颗粒Ⅰ—Ⅲ期；包涵体是由两种颗粒外包一界膜而形成，其中小而纤细的颗粒可能为游离的RLO，大而圆形的颗粒可能是吞噬溶酶体内RLO繁殖形成的微克隆。 |
| 关键词: 大珠母贝 类立克次体 包涵体 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院重点课题资助项目，KS85－121号 |
附件 |
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| STUDIES ON THE RICKETTSIA-LIKE ORGANISM DISEASES OF TROPICAL MARINE PEARL OYSTER—THE MORPHOLOGY, MORPHOGENESIS AND ULTRASTRUCTURE OF RLOINCLUSIONS, AN AGENT FOR PINCTADA MAXIMA |
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WU Xin-zhong, PAN Jin-pei
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South China Sea Institute of Oceanology,the Chinese Academy of Sciences,Guanhzhou,510301
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| Abstract: |
| The morphology, morphogenesis and ultrastructure of rickettsia-like organism (RLO) inclusion in 5-month-old diseased or moribund pearl oysters, Pinctada maxima, collected from the Xinying Bay, Hainan Island in November 1993 and November 1994 were described. For a histological examination the mantle, gills, hepatopancreas (including parts of stomach and intestine), return, adductor muscle, foot muscle and keber’s organ were dissected and fixed in bouin’s fixative and 4% neutral formalin fixative. Sections were stained with routine Ehrlich’s H.E procedure and special methods including Gram-Weigert’s staining and Ziehl-Neelsen and Wade-Fite for acid-fast staining. For scanning electron microscopy (SEM) analysis fresh specimens were fixed in 2% glutaraldehyde. The selected small pieces (1mm3) of mantle tissues were shaved with a double edged razor blade and washed with a sodium cacodylate buffer (three time, 30min/time). Dried tissues with the shaved surfaces exposed were sputter coated with gold-palladium. The characteristics of RLO inclusion distributions in tissues showed that all kinds of epithelial, connective tissue and endothelial cells are the target cells for RLO infection. The morphology and size of inclusions from different tissues are different. The inclusions are Gram negative but variable with developing inclusions, Acid-fast-positive in which bright red when stained with Wade-Fite’s stain and reddish black when stained with Ziehl-Neelsen’s stain. Pregranular and granular stages of developing inclusions were noted under light microscopic examination. The granular stage may be distinguished from stage I to stage III (gsI to gsIII). At the pregranular stage (pgi) the inclusions do not contain granules. Gram stain was poor and host cell has slightly hypertrophied. From granular stage I to stage III, inclusions contain developing granules which became more (tens up to 100) and larger (1.0–4.0μm as measured in gsIII inclusions). Gram stain varied from pale red or pale blue to purplish red with blue and host cell becoming much more hypertrophied, at last ruptured. Ulreastructurally, two stereo-structure granules, small granules (average 645.85×359.09μm) and large granules (average 2090.93×1556.08μm), in inclusion positive host cells were observed under SEM, in which some small granules were undergoing transverse binary fission (Fig.1:b) and budding division (Fig.1:c), and the large granule was undergoing ruptured with organism escaping (Fig.1:d). Combined the present results observed by light and SEM with previous transmission electron microscopy. It is suggested that RLO inclusions consist of two different granules surrounded by a membrane-bound, in which the fine granules may be free individual RLO and the large granules may be RLO microclonies involved in phagolysosomes. |
| Key words: Pinctada maxima, Rickettsia-like organism, Inclusions |
