Studies on spore dimorphism of the microsporidia

本研究的目的是确定家蚕微孢子虫两种类型的孢子在家蚕幼虫细胞中的发育情况，并检测其他微孢子虫是否产生这两种类型的孢子。这些孢子首先是在培养细胞中发现的，其次是N。接种家蚕。其中一种类型的孢子的特征是3-5个极管盘绕，早期发育(接种后36h)，并自发排出一个短的极管。另一种为极管10~12圈，发育较晚(接种后54h)。结果表明：1)经口接种后，两种类型的孢子在家蚕幼虫中肠上皮细胞中发育。2)一新的微孢子虫。是从草坪地老虎中分离出来的。这种微孢子虫产生的两种孢子与家蚕中发现的完全相同，但它不通过口服孢子感染家蚕，其孢子也不与用抗家蚕微孢子单抗致敏的乳胶粒发生反应。这种微孢子虫在整个发育过程中有两个双核排列的核。一个分生孢子产生两个孢子，没有孢子囊泡。因此，它是另一种微孢子虫。从德氏链霉菌中分离得到。3)我们还鉴定了在培养细胞中发育的两种类型的白僵菌孢子。此外，还分离到一个早期发育的孢子，并成功地接种到培养细胞上，获得了较高的侵染率。这些结果表明，这种孢子二型性是微孢子虫属微孢子虫的共同特征。

The purpose of present research was to make sure the development of two types of spores of Nosema bombycis in cells of the silkworm larvae, and examine other microsporidia whether they produce the two types of spores or not. Those spores were discovered first in cultured cells after N . bombycis was inoculated. One type of those spors is characterized by 3 to 5 coils of the polar tube, early development (36 h postinoculation), and the spontaneous discharge of a short polar tube. The other is characterized by 10 to 12 coils of the polar tube and the late development (54 h postinoculation).The results are summerized as below, 1) The two types of spores were confirmed to develop in midgut epithelial cells of the silkworm larvae after peroral inoculation. 2) A new Nosema sp. was isolated from the lawn grass cutworm, Spodoptera deprauata. This microsporidium produced two types of spores exactly the same ones as found in N.bombycis, while it did not infect the silkworm by oral administration of spores, and its spores did not react with latex particles whic had been sensitized with a monoclonal antibody against spores of N.bombycis. This microsporidium had two nuclei in diplokaryotic arrangement throughout its development. A meront gave rise to two spores, and there was no sporophorous vesicle. Hence it is another Nosema sp. isolated from S.deprauata. 3) We also identified the two types of spores in N.furnacalis developing in cultured cells. Furthermore, one of spore, early developing one, was isolated and successfully inoculated onto cultured cells, giving high rate of infection.These results indicate that this spore dimorphism is a character shared by microsporidia belonging to the genus Nosema.