Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
Parasit Vectors. 2022 Mar 2;15(1):70. doi: 10.1186/s13071-022-05191-0.
Ancylostoma species are hematophagous parasites that cause chronic hemorrhage in various animals and humans. Pangolins, also known as scaly anteaters, are mammals that live in soil environments where they are readily exposed to soil-borne parasitic nematodes. However, only a limited number of helminth species have been identified in this animal host so far.
Ancylostoma sp. was isolated from a wild pangolin, and the complete mitochondrial (mt) genome of Ancylostoma sp. was obtained by Illumina sequencing of total genomic DNA.
The circular complete mt genome that was assembled had a total length of 13,757 bp and comprised 12 protein-coding genes (PCGs), 22 transfer ribosomal RNAs, two ribosomal RNAs (rRNAs), two non-coding regions and one AT-rich region, but lacked the gene coding for ATPase subunit 8 (atp8). The overall AT content of the mt genome of Ancylostoma sp. was 76%, which is similar to that of other nematodes. The PCGs used two start codons (ATT and TTG) and three stop codons (TAA, TAG, and T). The nucleotide identity of the 12 PCGs ranged from 83.1% to 89.7% and had the highest sequence identity with Ancylostoma caninum among species in the Ancylostomatidae family. Also, the pangolin-derived Ancylostoma sp. lacked repeat sequences in the non-coding regions and in the unique sequence of the short non-coding regions, which differentiated it from other Ancylostoma species. In addition, phylogenetic analyses of 18S rRNA and mtDNA sequences revealed that the Ancylostoma sp. was positioned in a separate branch in the subfamily Ancylostomatinae along with other Ancylostoma species.
The Ancylostoma sp. isolated from a pangolin in this study was identified as a possible new Ancylostoma species. The identification of this Ancylostoma sp. from pangolin enriches our knowledge of the species in the Ancylostomatidae family and provides information that will lead to a better understanding of the taxonomy, diagnostics, and biology of hookworms.
Ancylostoma 是一种血吸性寄生虫，可导致多种动物和人类慢性出血。穿山甲又称鳞甲食蚁兽，是生活在土壤环境中的哺乳动物，容易接触到土壤传播的寄生性线虫。然而，到目前为止，在这种动物宿主中只鉴定出了有限数量的蠕虫物种。
从野生穿山甲中分离出Ancylostoma sp.，并通过对总基因组 DNA 进行 Illumina 测序获得 Ancylostoma sp.的完整线粒体 (mt) 基因组。
组装的圆形完整 mt 基因组全长 13757bp，包含 12 个蛋白质编码基因 (PCGs)、22 个转移核糖体 RNA、2 个核糖体 RNA (rRNA)、2 个非编码区和 1 个富含 AT 的区，但缺少 ATPase 亚基 8 (atp8) 的基因编码。Ancylostoma sp. mt 基因组的总 AT 含量为 76%，与其他线虫相似。PCGs 使用两个起始密码子 (ATT 和 TTG) 和三个终止密码子 (TAA、TAG 和 T)。12 个 PCGs 的核苷酸同一性范围为 83.1%至 89.7%，与Ancylostomatidae 家族中的Ancylostoma caninum 物种具有最高的序列同一性。此外，从穿山甲中分离出的 Ancylostoma sp. 在非编码区和短非编码区的独特序列中缺乏重复序列，这使其与其他 Ancylostoma 物种不同。此外，18S rRNA 和 mtDNA 序列的系统发育分析表明，Ancylostoma sp. 在Ancylostomatinae 亚科中与其他 Ancylostoma 物种一起位于一个单独的分支中。
从本研究中穿山甲中分离出的 Ancylostoma sp. 被鉴定为可能的新 Ancylostoma 物种。从穿山甲中鉴定出这种 Ancylostoma sp.丰富了我们对 Ancylostomatidae 科物种的了解，并提供了更好地了解钩虫分类学、诊断学和生物学的信息。
