Brindley P J, Gazzinelli R T, Denkers E Y, Davis S W, Dubey J P, Belfort R, Martins M C, Silveira C, Jamra L, Waters A P
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
Am J Trop Med Hyg. 1993 Mar;48(3):447-56. doi: 10.4269/ajtmh.1993.48.447.
The tachyzoite of the human pathogen Toxoplasma gondii is morphologically indistinguishable from the proliferative stages of some other zoonotic coccidia, including Sarcocystis. To determine the identity of such coccidia obtained from human tissues and other sources, we compared riboprints (through restriction enzyme analysis of the polymerase chain reaction [PCR]-amplified small subunit rRNA gene) of the following protozoa: the RH and ts-4 strains of T. gondii, lines OH3 and S11, which are two recently isolated T. gondii-like parasites from Brazil, Neospora caninum, Sarcocystis species, and the malarial parasite Plasmodium berghei. In addition, the protozoan genomes were examined by PCR for homologs of surface antigen genes of T. gondii, and by Southern hybridization to the heterologous rRNA gene probe pSM 389. Strains OH3, S11, ts-4, and RH shared identical riboprints, and OH3, S11, and ts-4 have p22 and p30 surface antigen gene structures similar to RH. In contrast, riboprints for N. caninum and T. gondii differ with respect to Dde 1 sites, and moreover, their genomes vary significantly from one another at both the p22 and p30 gene loci. The riboprints of Sarcocystis and P. berghei differ markedly from T. gondii and N. caninum and from each other. Bam HI pSM 389 restriction fragment length polymorphisms differentiate ts-4 from RH, OH3, and S11. Our results confirm that OH3 and S11 are indeed T. gondii, but that N. caninum and T. gondii are likely to be separate species, thereby resolving previous uncertainties concerning the identity of these parasites. Together, the variation in riboprints and surface antigen gene structure reflects the phylogenetic diversity among these coccidia, and in addition, confirms the value of riboprinting in the identification of apicomplexan parasites such as T. gondii.
人类病原体刚地弓形虫的速殖子在形态上与包括肉孢子虫在内的其他一些人兽共患球虫的增殖阶段无法区分。为了确定从人体组织和其他来源获得的此类球虫的身份，我们比较了以下原生动物的核糖体印记（通过对聚合酶链反应[PCR]扩增的小亚基rRNA基因进行限制性酶切分析）：刚地弓形虫的RH和ts-4菌株、OH3和S11系，这是最近从巴西分离出的两种类似刚地弓形虫的寄生虫、犬新孢子虫、肉孢子虫属物种以及疟原虫伯氏疟原虫。此外，通过PCR检测原生动物基因组中刚地弓形虫表面抗原基因的同源物，并通过与异源rRNA基因探针pSM 389进行Southern杂交。OH3、S11、ts-4和RH菌株具有相同的核糖体印记，并且OH3、S11和ts-4具有与RH相似的p22和p30表面抗原基因结构。相比之下，犬新孢子虫和刚地弓形虫的核糖体印记在Dde 1位点上有所不同，而且它们的基因组在p22和p30基因位点上彼此也有显著差异。肉孢子虫和伯氏疟原虫的核糖体印记与刚地弓形虫和犬新孢子虫明显不同，且彼此也不同。Bam HI pSM 389限制性片段长度多态性可区分ts-4与RH、OH3和S11。我们的结果证实OH3和S11确实是刚地弓形虫，但犬新孢子虫和刚地弓形虫可能是不同的物种，从而解决了先前关于这些寄生虫身份的不确定性。核糖体印记和表面抗原基因结构的变化共同反映了这些球虫之间的系统发育多样性，此外，还证实了核糖体印记在鉴定诸如刚地弓形虫等顶复门寄生虫方面的价值。
