Introduction: Nicotine degradation is a new strategy to block nicotine-induced pathology. The potential of human microbiota to degrade nicotine has not been explored. Aims: This study aimed to uncover the genomic potentials of human microbiota to degrade nicotine. Method: To address this issue, we performed a systematic annotation of Nicotine-Degrading Enzymes (NDEs) from genomes and metagenomes of human microbiota. A total of 26,295 genomes and 1,596 metagenomes for human microbiota were downloaded from public databases and five types of NDEs were annotated with a custom pipeline. We found 959 NdhB, 785 NdhL, 987 NicX, three NicA1, and three NicA2 homologs. Results: Genomic classification revealed that six phylum-level taxa, including Proteobacteria, Firmicutes, Firmicutes_A, Bacteroidota, Actinobacteriota, and Chloroflexota, can produce NDEs, with Proteobacteria encoding all five types of NDEs studied. Analysis of NicX prevalence revealed differences among body sites. NicX homologs were found in gut and oral samples with a high prevalence but not found in lung samples. NicX was found in samples from both smokers and non-smokers, though the prevalence might be different.

中文翻译：

---

人类微生物群中尼古丁降解酶分布的基因组和宏基因组见解

简介：尼古丁降解是阻止尼古丁引起的病理的一种新策略。人类微生物群降解尼古丁的潜力尚未被探索。目的：本研究旨在揭示人类微生物群降解尼古丁的基因组潜力。方法：为了解决这个问题，我们对人类微生物群的基因组和宏基因组中的尼古丁降解酶（NDE）进行了系统注释。从公共数据库下载了总共 26,295 个人类微生物组基因组和 1,596 个宏基因组，并使用自定义管道注释了五种类型的濒死体验。我们发现了 959 个 NdhB、785 个 NdhL、987 个 NicX、三个 NicA1 和三个 NicA2 同源物。结果：基因组分类显示，变形菌门、厚壁菌门、厚壁菌门_A、拟杆菌门、放线菌门和绿曲菌门等 6 个门级分类单元可以产生 NDE，其中变形菌门编码所研究的所有五种类型的 NDE。对 NicX 患病率的分析揭示了身体部位之间的差异。 NicX 同源物在肠道和口腔样本中被发现，且流行率很高，但在肺部样本中未发现。尽管患病率可能不同，但吸烟者和非吸烟者的样本中都发现了 NicX。