Ranjit N, Jones M K, Stenzel D J, Gasser R B, Loukas A
Division of Infectious Diseases and Immunology, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, QLD 4006, Australia.
Int J Parasitol. 2006 May 31;36(6):701-10. doi: 10.1016/j.ijpara.2006.01.015. Epub 2006 Mar 6.
The gastrointestinal tracts of multi-cellular blood-feeding parasites are targets for vaccines and drugs. Recently, recombinant vaccines that interrupt the digestion of blood in the hookworm gut have shown efficacy, so we explored the intestinal transcriptomes of the human and canine hookworms, Necator americanus and Ancylostoma caninum, respectively. We used Laser Microdissection Microscopy to dissect gut tissue from the parasites, extracted the RNA and generated cDNA libraries. A total of 480 expressed sequence tags were sequenced from each library and assembled into contigs, accounting for 268 N. americanus genes and 276 A. caninum genes. Only 17% of N. americanus and 36% of A. caninum contigs were assigned Gene Ontology classifications. Twenty-six (9.8%) N. americanus and 18 (6.5%) A. caninum contigs did not have homologues in any databases including dbEST-of these novel clones, seven N. americanus and three A. caninum contigs had Open Reading Frames with predicted secretory signal peptides. The most abundant transcripts corresponded to mRNAs encoding cholesterol-and fatty acid-binding proteins, C-type lectins, Activation-Associated Secretory Proteins, and proteases of different mechanistic classes, particularly astacin-like metallopeptidases. Expressed sequence tags corresponding to known and potential recombinant vaccines were identified and these included homologues of proteases, anti-clotting factors, defensins and integral membrane proteins involved in cell adhesion.
多细胞吸血寄生虫的胃肠道是疫苗和药物的作用靶点。最近，能够阻断钩虫肠道内血液消化的重组疫苗已显示出疗效，因此我们分别探究了人体钩虫美洲板口线虫和犬钩虫犬钩口线虫的肠道转录组。我们使用激光显微切割显微镜从寄生虫中分离肠道组织，提取RNA并构建cDNA文库。每个文库共对480个表达序列标签进行了测序并组装成重叠群，其中包括268个美洲板口线虫基因和276个犬钩口线虫基因。美洲板口线虫重叠群中只有17%、犬钩口线虫重叠群中只有36%被赋予了基因本体分类。26个（9.8%）美洲板口线虫重叠群和18个（6.5%）犬钩口线虫重叠群在包括dbEST在内的任何数据库中都没有同源物——在这些新克隆中，7个美洲板口线虫重叠群和3个犬钩口线虫重叠群具有带有预测分泌信号肽的开放阅读框。最丰富的转录本对应于编码胆固醇和脂肪酸结合蛋白、C型凝集素、激活相关分泌蛋白以及不同机制类别的蛋白酶（特别是类虾红素金属肽酶）的mRNA。鉴定出了与已知和潜在重组疫苗相对应的表达序列标签，其中包括蛋白酶、抗凝血因子、防御素以及参与细胞黏附的整合膜蛋白的同源物。
