BACKGROUND Biomphalaria glabrata snails are widely distributed in schistosomiasis endemic areas like America and Caribe, displaying high susceptibility to infection by Schistosoma mansoni. After the availability of B. glabrata genome and transcriptome data, studies focusing on genetic markers and small non-coding RNAs have become more relevant. The small RNAs have been considered important through their ability to finely regulate the gene expression in several organisms, thus controlling the functions like cell growth, metabolism, and susceptibility/resistance to infection. OBJECTIVE The present study aims on identification and characterisation of the repertoire of small non-coding RNAs in B. glabrata (Bgl-small RNAs). METHODS By using small RNA sequencing, bioinformatics tools and quantitative reverse transcription polymerase chain reaction (RT-qPCR), we identified, characterised, and validated the presence of small RNAs in B. glabrata. FINDINGS 89 mature miRNAs were identified and five of them were classified as Mollusk-specific. When compared to model organisms, sequences of B. glabrata miRNAs showed a high degree of conservation. In addition, several target genes were predicted for all the mature miRNAs identified. Furthermore, piRNAs were identified in the genome of B. glabrata for the first time. The B. glabrata piRNAs showed strong conservation of uridine as first nucleotide at 5’ end, besides adenine at 10th position. Our results showed that B. glabrata has diverse repertoire of circulating ncRNAs, several which might be involved in mollusk susceptibility to infection, due to their potential roles in the regulation of S. mansoni development. MAIN CONCLUSIONS Further studies are necessary in order to confirm the role of the Bgl-small RNAs in the parasite/host relationship thus opening new perspectives on interference of small RNAs in the organism development and susceptibility to infection.

中文翻译：

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小RNA的深度测序揭示了光滑小球藻中miRNA和piRNA的全部组成。

背景技术欧洲草Bio蜗牛在美国和加勒比海等血吸虫病流行地区广泛分布，对曼氏血吸虫感染表现出很高的敏感性。在获得了B. glabrata基因组和转录组数据后，针对遗传标记和小的非编码RNA的研究变得更加相关。人们认为小RNA具有重要作用，因为它们能够精细调节几种生物体中的基因表达，从而控制细胞生长，代谢和对感染的敏感性/抵抗力等功能。目的本研究旨在鉴定和鉴定光滑芽孢杆菌中的小非编码RNA（Bgl-small RNA）的组成。方法通过小RNA测序，生物信息学工具和定量逆转录聚合酶链反应（RT-qPCR），我们鉴定，鉴定和验证了光滑小芽孢杆菌中小RNA的存在。结果鉴定出89个成熟的miRNA，其中五个被分类为软体动物特异性的。当与模型生物比较时，glabrata B. miRNA的序列显示出高度的保守性。另外，对于所有鉴定出的成熟miRNA，预测了几种靶基因。此外，piRNAs首次在光滑芽孢杆菌的基因组中鉴定。光滑芽孢杆菌piRNA除了在第10位的腺嘌呤外，在5'端还显示出尿苷作为第一个核苷酸的强保守性。我们的研究结果表明，光滑芽孢杆菌具有多种多样的循环ncRNA，其中一些可能与软体动物对感染的敏感性有关，由于它们在调节曼氏沙门氏菌发育中的潜在作用。主要结论为了确定Bgl-小RNA在寄生虫/宿主关系中的作用，有必要进行进一步的研究，从而为小RNA干扰生物发展和易感性开辟新的视角。