Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, México.
Centro de Bioinvestigaciones (CeBio) and Centro de Investigación y Transferencia del Noroeste de Buenos Aires (CITNOBA-CONICET), Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino, Argentina.
BMC Genomics. 2018 Apr 27;19(1):296. doi: 10.1186/s12864-018-4696-8.
Chagas disease is a parasitic infection caused by Trypanosoma cruzi. It is an important public health problem affecting around seven to eight million people in the Americas. A large number of hematophagous triatomine insect species, occupying diverse natural and human-modified ecological niches transmit this disease. Triatomines are long-living hemipterans that have evolved to explode different habitats to associate with their vertebrate hosts. Understanding the molecular basis of the extreme physiological conditions including starvation tolerance and longevity could provide insights for developing novel control strategies. We describe the normalized cDNA, full body transcriptome analysis of three main vectors in North, Central and South America, Triatoma pallidipennis, T. dimidiata and T. infestans.
Two-thirds of the de novo assembled transcriptomes map to the Rhodnius prolixus genome and proteome. A Triatoma expansion of the calycin family and two types of protease inhibitors, pacifastins and cystatins were identified. A high number of transcriptionally active class I transposable elements was documented in T. infestans, compared with T. dimidiata and T. pallidipennis. Sequence identity in Triatoma-R. prolixus 1:1 orthologs revealed high sequence divergence in four enzymes participating in gluconeogenesis, glycogen synthesis and the pentose phosphate pathway, indicating high evolutionary rates of these genes. Also, molecular evidence suggesting positive selection was found for several genes of the oxidative phosphorylation I, III and V complexes.
Protease inhibitors and calycin-coding gene expansions provide insights into rapidly evolving processes of protease regulation and haematophagy. Higher evolutionary rates in enzymes that exert metabolic flux control towards anabolism and evidence for positive selection in oxidative phosphorylation complexes might represent genetic adaptations, possibly related to prolonged starvation, oxidative stress tolerance, longevity, and hematophagy and flight reduction. Overall, this work generated novel hypothesis related to biological adaptations to extreme physiological conditions and diverse ecological niches that sustain Chagas disease transmission.
恰加斯病是由克氏锥虫引起的寄生虫感染。它是一个重要的公共卫生问题，影响着美洲大约 700 万到 800 万人。大量的吸血三锥虫昆虫物种，占据着不同的自然和人为改造的生态位，传播这种疾病。三锥虫是长寿命的半翅目昆虫，它们已经进化到可以在不同的栖息地爆炸，以与它们的脊椎动物宿主联系。了解包括饥饿耐受和长寿在内的极端生理条件的分子基础，可以为开发新的控制策略提供见解。我们描述了北、中、南美洲三种主要传播媒介 Triatoma pallidipennis、T. dimidiata 和 T. infestans 的正常化 cDNA 和全身体转录组分析。
三分之二的从头组装转录组映射到 Rhodnius prolixus 基因组和蛋白质组。鉴定了 calycin 家族的三锥虫扩张和两种类型的蛋白酶抑制剂，pacifastins 和 cystatins。与 T. dimidiata 和 T. pallidipennis 相比，T. infestans 记录了大量转录活性的 I 类转座元件。在 Triatoma-R. prolixus 1:1 直系同源物中的序列同一性显示，参与糖异生、糖原合成和戊糖磷酸途径的四个酶的序列高度分化，表明这些基因的进化速度很高。此外，还发现了氧化磷酸化 I、III 和 V 复合物的几个基因存在正选择的分子证据。
蛋白酶抑制剂和 calycin 编码基因的扩张为快速进化的蛋白酶调节和吸血过程提供了线索。对施加代谢通量控制以合成代谢的酶的更高进化速度以及氧化磷酸化复合物中存在正选择的证据，可能代表与长期饥饿、氧化应激耐受、长寿、吸血和飞行减少有关的遗传适应。总的来说，这项工作产生了与维持恰加斯病传播的极端生理条件和多样化生态位的生物适应相关的新假设。
