Martínez-Álvarez José A, Coria-Alcaraz Sandra Ethelvina, Ramírez-Montiel Fátima Berenice, Medina-Nieto Ana Laura, Andrade-Guillen Sairy Yarely, Gutiérrez Fátima Tornero-, Rangel-Serrano Ángeles, Vargas-Maya Naurú Idalia, García-Contreras Rodolfo, Padilla-Vaca Felipe, Franco Bernardo
División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Zip Code 36050, Guanajuato, Mexico.
División de Ciencias Naturales y Exactas, Departamento de Farmacia, Universidad de Guanajuato, Zip Code 36050, Guanajuato, Mexico.
Arch Microbiol. 2025 Sep 9;207(10):259. doi: 10.1007/s00203-025-04437-6.
Plasmids are fundamental to molecular biology and biotechnology, playing a crucial role in bacterial evolution. Some plasmids are linked to complex cellular dynamics, including pathogenicity islands, antibiotic resistance, and gene mobilization. This study reports the isolation and sequencing of two cryptic plasmids with different electrophoretic mobilities from the Escherichia coli clinical isolate O55. This strain was isolated based on its capacity to bind mannoses on the surface of yeast cells, a property that could be counteracted with methyl α-D-mannoside, a feature used to characterize yeast cell agglutination and, more recently, to assess virulence in Entamoeba histolytica. The strain exhibited no growth differences compared to the laboratory strain E. coli BW25113. Attempts to transform the plasmids independently were unsuccessful; however, they remained stable when the cells were co-transformed. Sequence analysis revealed that both plasmids have conserved counterparts in GenBank (over 100 sequences in Enterobacteriaceae) and can be classified into two distinct groups, regardless of host strain or species. Additionally, in E. coli and Klebsiella pneumoniae isolates, the smaller plasmid was identified as an integrated copy into the genome, aligning with the observation that the plasmids cannot be maintained separately. ORF content analysis identified only putative proteins except for two, one associated with the resistance to aminoglycosides (a functional aminoglycoside O-phosphotransferase), a putative sulfonamide resistance gene, and another associated with a replication protein, suggesting that one plasmid regulates the replication of the other based on AlphaFold3 DNA-protein models. Our findings underscore the importance of further analyzing plasmids in next-generation sequencing data from clinical samples to enhance our understanding of plasmid biology and their impact on the dissemination of pathogenesis-related traits in bacteria.
质粒是分子生物学和生物技术的基础，在细菌进化中起着关键作用。一些质粒与复杂的细胞动态相关，包括致病岛、抗生素抗性和基因转移。本研究报告了从大肠杆菌临床分离株O55中分离出两种具有不同电泳迁移率的隐蔽质粒并进行测序。该菌株是根据其结合酵母细胞表面甘露糖的能力分离出来的，这种特性可以被α-D-甲基甘露糖苷抵消，这一特征用于表征酵母细胞凝集，最近也用于评估溶组织内阿米巴的毒力。与实验室菌株大肠杆菌BW25113相比，该菌株没有生长差异。单独转化这些质粒的尝试未成功；然而，当细胞共转化时，它们保持稳定。序列分析表明，这两种质粒在GenBank中都有保守的对应序列（肠杆菌科中有超过100个序列），并且可以分为两个不同的组，无论宿主菌株或物种如何。此外，在大肠杆菌和肺炎克雷伯菌分离株中，较小的质粒被鉴定为基因组中的整合拷贝，这与质粒不能单独维持的观察结果一致。开放阅读框（ORF）内容分析仅鉴定出两个推定蛋白以外的推定蛋白，一个与对氨基糖苷类的抗性相关（一种功能性氨基糖苷O-磷酸转移酶），一个推定的磺胺抗性基因，另一个与复制蛋白相关，这表明一种质粒根据AlphaFold3 DNA-蛋白质模型调节另一种质粒的复制。我们的研究结果强调了在临床样本的下一代测序数据中进一步分析质粒的重要性，以增强我们对质粒生物学及其对细菌中致病相关性状传播影响的理解。
