腔阔盘吸虫尾蚴及后蚴穿刺腺等腺体的组织化学及其功能的初步研究

本文报道应用组织化学反应方法初步观察了腔阔盘吸虫(Eurytrema coelomaticum)尾蚴及后蚴体中单细胞腺的组织化学成分及其生理功能。尾蚴的5对大单细胞腺主要分泌粘蛋白、酸性粘多糖及微量碱性蛋白质,当子胞蚴被排到外界时,此腺体物质分泌出充满子胞蚴内囊腔并包被着各尾蚴。尾蚴在此腺体分泌物保护下渡过其在外界生存的时间。尾蚴的4对小单细胞腺主要包含中性糖蛋白及结合氨基的蛋白质(可能是含酶物质),此腺体物质可能是在尾蚴进入昆虫宿主(草螽)体内穿钻其胃壁进入血腔时分泌出能溶解胃壁组织帮助尾蚴的穿钻行为。成熟后蚴的穿刺腺对PAS反应呈强阳性,其分泌物可以溶解囊蚴的囊壁,使后蚴迅速脱囊。各幼虫期其他器官组织的组化成分也经观察。

PRELIMINARY HISTOCHEMICAL STUDIES ON THE UNICELLULAR GLANDS OF THE CERCARIA AND METACERCARIA OF EURYTREMA COELOMATICUM, WITH SPECIAL EMPHASIS ON THEIR PHYSIOLOGICAL FUNCTION AND BEHAVIOR

There are two .type of unicellular glands situated on both sides of oesophagus and aceta-bulum on the fore and middle body of the ceraria of Eurylrema coelomaticum. The ducts of these glands are grouped in four bundles, two on each lateral side of the body, another along both sides of oesophagus. They proceed forward and open to the stylet pocket. This paper reports the result of our histochemical studies to inquire into the nature of their composition and the role their secretions play in the life and behavior of the cercaria. The techniques used included methods such as Periodic-acid-Schiff (with and without amylase digestion) for carbohydrates; Mucicarmine for mucoprotcin; Alcianblue-PAS for acid mucopolysaccharide and neutral mucopolysaccharide; Mercurybromophenol-blue (HgBPB) for basic protein and Ninhydrin-Schiff for Protein-boundamino (HN2). The results obtained may be summarized as follows:(1) Four pairs of small unicellular glands situated on both sides of oesophagus of the E. coelomaticum cercaria are identified as penetration glands, while the other five larger unicellular pairs occupying the dorsal and lateral parts of the acetabulum are gland cells containing muco-substances.(2) The small penetration gland cells contain mainly protein-bound-amino(NHs) and neutral mucopolysaccharide. The large mucosubstance gland cells contain mainly acid mucopolysaccharide and mucoprotein.(3) Almost the whole content of mucosubstances gland cells of the cercariae are being secreted, while the daughter sporocysts are expelled from the snail-host to the outside air. The secretions of these larger gland cells when secreted become the protective covering of the cercariae, inside the inner cyst wall. The function of the mucosubstance is for protecting the cercariae to bridge over the atmospheric influences (perhaps to avoid drying) before the cercariae are ingested by the meadow grasshopper, Conocephalus maculatus. Its function is so significantly observed by the contracting movement of the inner sporocyst wall.(4) During the whole cercarial stage the small penetration gland cells can be observed to contain their glandular material while after their penetrating into the haemocoel, the material diminishes. They can only be seen occasionaly in some one-day old metacercariae. The mucosubstances in the larger gland cells can not be seen at all inside the body of the insect host.(5) In mature metacercariae of 25 to 30 days another kind of penetration gland cells emerge. These new glands occupying the area between the oral sucker and acetabulum of the metacercaria. They contain PAS positive materials. The phenomenon of excystation of the ine-tacercarial cyst has been observed in vitro, when the cysts were treated with trypsin for a few minutes. The process continue to work and in four hours the metacercariae were completely excysted. Although trypsin seem to activate the process, its presence only stimulates the activity of the metacercaria inducing it to secrete the contents of the penetration glands. Very fine granules were observed to come out from the gland ducts and gather at their tips. These granules can dissolve the cyst wall making a tunnel through which the metacercaria emerges.(6) The body wall of daughter sporocyst and some other organs of the cercaria were also observed. The outer walls contain mainly neutral mucopolysaceharide, inner walls contain mainly acid mucopolysaccharide and both have some protein substances. The genital primordia in cercaria and metacercaria contain much DNA and some protein bound amino (NH,)- The outer layer of body cells and oral and ventral suckers in cercaria and metacercaria both contain glycogen.