Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA.
Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
Appl Environ Microbiol. 2021 Apr 27;87(10). doi: 10.1128/AEM.02082-20.
Leeches are found in terrestrial, aquatic, and marine habitats on all continents. Sanguivorous leeches have been used in medicine for millennia. Modern scientific uses include studies of neurons, anticoagulants, and gut microbial symbioses. , the European medicinal leech, maintains a gut community dominated by two bacterial symbionts, and , which sometimes account for as much as 97% of the total crop microbiota. The highly simplified gut anatomy and microbiome of make it an excellent model organism for studying gut microbial dynamics. The North American medicinal leech, , is a hirudinid leech native to Canada and the northern United States. In this study, we show that symbiont communities are very similar to those in We performed an extensive study using field-caught and purchased from two suppliers. Deep sequencing of the V4 region of the 16S rRNA gene allowed us to determine that the core microbiome of consists of , , and The analysis revealed that the compositions of the gut microbiomes of the two leech species were significantly different at all taxonomic levels. The value was highest at the genus and amplicon sequence variant (ASV) levels and much lower at the phylum, class, and order levels. The gut and bladder microbial communities were distinct. We propose that is an alternative to for studies of wild-caught animals and provide evidence for the conservation of digestive-tract and bladder symbionts in annelid models. Building evidence implicates the gut microbiome in critical animal functions such as regulating digestion, nutrition, immune regulation, and development. Simplified, phylogenetically diverse models for hypothesis testing are necessary because of the difficulty of assigning causative relationships in complex gut microbiomes. Previous research used as a tractable animal model of digestive-tract symbioses. Our data show that may work just as well without the drawback of being an endangered organism and with the added advantage of easy access to field-caught specimens. The similarity of the microbial community structures of species from two different continents reveals the highly conserved nature of the microbial symbionts in sanguivorous leeches.
蛭类分布于各大洲的陆地、水生和海洋生境中。吸血蛭类在医学上已经使用了数千年。现代科学用途包括对神经元、抗凝血剂和肠道微生物共生体的研究。欧洲医用水蛭维持着一种肠道群落，主要由两种细菌共生体和组成，有时占总作物微生物群的 97%。高度简化的肠道解剖结构和微生物组使它成为研究肠道微生物动态的理想模型生物。北美的医用水蛭，原产于加拿大和美国北部，是一种蛭科蛭类。在这项研究中，我们表明，其共生体群落与欧洲医用水蛭非常相似。我们使用从两个供应商购买的野外捕获的和进行了广泛的研究。16S rRNA 基因 V4 区的深度测序使我们能够确定的核心微生物组由、和组成。分析表明，两种蛭类的肠道微生物组在所有分类水平上的组成都有显著差异。值在属和扩增子序列变体（ASV）水平上最高，在门、纲和目水平上则低得多。肠道和膀胱微生物群落是不同的。我们提出可以替代欧洲医用水蛭用于野生动物的研究，并为环节动物模型中消化肠道和膀胱共生体的保护提供证据。越来越多的证据表明，肠道微生物组在调节消化、营养、免疫调节和发育等关键动物功能中发挥作用。由于在复杂的肠道微生物组中难以确定因果关系，因此需要简化的、系统发育多样的假设检验模型。以前的研究使用欧洲医用水蛭作为消化道共生的可处理动物模型。我们的数据表明，可能同样有效，而没有作为濒危生物的缺点，并且具有更容易获得野外捕获标本的额外优势。来自两个不同大陆的物种的微生物群落结构的相似性揭示了吸血蛭类肠道微生物共生体的高度保守性质。
