Mazars E, Odberg-Ferragut C, Dei-Cas E, Fourmaux M N, Aliouat E M, Brun-Pascaud M, Mougeot G, Camus D
INSERM (U. 42), Villeneuve d'Ascq, France.
J Eukaryot Microbiol. 1995 Jan-Feb;42(1):26-32. doi: 10.1111/j.1550-7408.1995.tb01536.x.
Pneumocystis carinii is an opportunistic agent found in the lung of various mammals which often causes severe pneumonia in immunocompromised humans, especially in AIDS patients. In the past several years significant additions have been made to the collection of knowledge we have concerning the genetic diversity of P. carinii. These additions provide new understanding of Pneumocystis transmission and the effect of possible reservoirs of Pneumocystis in the various species. In this study, a 400-bp fragment of the thymidylate synthase (TS) gene of P. carinii has been amplified by PCR from 43 parasite isolates obtained from 4 mammalian host species: rat, mouse, rabbit and human. A probe selected from the TS gene sequence of rat-derived P. carinii was hybridized with the amplified products from rat- and mouse-derived P. carinii, but not with rabbit or human P. carinii DNA. Restriction profiles were performed on amplified fragments from all isolates, and the 4 nucleotide sequences of the TS gene fragment amplified from rat, mouse, rabbit and human P. carinii were determined. Differences were detected in the gene fragment in P. carinii isolates from the 4 host species; however no difference was revealed in P. carinii isolates within a single host species, whatever the host strain or its geographic origin. Thus, the sequence differences of the P. carinii TS gene appeared as host-species specific. A specific probe which recognized all human P. carinii isolates was defined.
卡氏肺孢子虫是一种在多种哺乳动物肺部发现的机会性病原体，它常导致免疫功能低下的人类，尤其是艾滋病患者发生严重肺炎。在过去几年中，我们对卡氏肺孢子虫遗传多样性的认识有了显著增加。这些新认识为肺孢子虫的传播以及不同物种中肺孢子虫可能的储存宿主的影响提供了新的理解。在本研究中，通过聚合酶链反应（PCR）从4种哺乳动物宿主物种（大鼠、小鼠、兔子和人类）获得的43个寄生虫分离株中扩增出了卡氏肺孢子虫胸苷酸合成酶（TS）基因的一个400碱基对片段。从大鼠来源的卡氏肺孢子虫TS基因序列中选择的一个探针与大鼠和小鼠来源的卡氏肺孢子虫的扩增产物杂交，但不与兔子或人类来源的卡氏肺孢子虫DNA杂交。对所有分离株的扩增片段进行了限制性酶切图谱分析，并测定了从大鼠、小鼠、兔子和人类卡氏肺孢子虫中扩增出的TS基因片段的4个核苷酸序列。在来自4种宿主物种的卡氏肺孢子虫分离株的基因片段中检测到了差异；然而，在单一宿主物种内的卡氏肺孢子虫分离株中未发现差异，无论宿主菌株或其地理来源如何。因此，卡氏肺孢子虫TS基因的序列差异表现为宿主物种特异性。定义了一种能识别所有人类卡氏肺孢子虫分离株的特异性探针。
