Morales-Blancas Giselle Yamilet, Reyna-Terán José Daniel, Hernández-Eligio José Alberto, Ortuño-Pineda Carlos, Toribio-Jiménez Jeiry, Rodríguez-Barrera Miguel Ángel, Toledo-Hernández Erubiel, Rojas-Aparicio Augusto, Romero-Ramírez Yanet
Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Unidad Académica de Ciencias Químico- Biológicas, Universidad Autónoma de Guerrero, Avenida Lázaro Cárdenas sin número, Ciudad Universitaria, Chilpancingo, Guerrero, C. P. 39070, México.
Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, C. P. 62210, México.
World J Microbiol Biotechnol. 2023 Apr 28;39(7):177. doi: 10.1007/s11274-023-03630-3.
Benzopyrene is a high-molecular-weight polycyclic aromatic hydrocarbon that is highly recalcitrant and induces carcinogenic effects. CsrA is a conserved regulatory protein that controls the translation and stability of its target transcripts, having negative or positive effects depending on the target mRNAs. It is known that Bacillus licheniformis M2-7 has the ability to grow and survive in certain concentrations of hydrocarbons such as benzopyrene, prompted in part by CsrA, as is present in gasoline. However, there are a few studies that reveal the genes involved in that process. To identify the genes involved in the Bacillus licheniformis M2-7 degradation pathway, the plasmid pCAT-sp containing a mutation in the catE gene was constructed and used to transform B. licheniformis M2-7 and generate a CAT1 strain. We determined the capacity of the mutant B. licheniformis (CAT1) to grow in the presence of glucose or benzopyrene as a carbon source. We observed that the CAT1 strain presented increased growth in the presence of glucose but a statistically considerable decrease in the presence of benzopyrene compared with the wild-type parental strain. Additionally, we demonstrated that the Csr system positively regulates its expression since it was observed that the expression of the gene in the mutant strain LYA12 (M2-7 csrA:: Sp, SpR) was considerably lower than that in the wild-type strain. We were thus able to propose a putative regulation model for catE gene in B. licheniformis M2-7 strain by CsrA regulator in the presence of benzopyrene.
苯并芘是一种高分子量的多环芳烃，具有高度难降解性并可诱发致癌作用。CsrA是一种保守的调节蛋白，可控制其靶转录本的翻译和稳定性，根据靶mRNA的不同产生负向或正向影响。已知地衣芽孢杆菌M2-7有能力在一定浓度的碳氢化合物（如苯并芘）中生长和存活，这部分是由CsrA促成的，汽油中也存在CsrA。然而，揭示参与该过程的基因的研究较少。为了鉴定参与地衣芽孢杆菌M2-7降解途径的基因，构建了catE基因发生突变的质粒pCAT-sp，并用于转化地衣芽孢杆菌M2-7以产生CAT1菌株。我们测定了突变型地衣芽孢杆菌（CAT1）在以葡萄糖或苯并芘作为碳源的情况下生长的能力。我们观察到，与野生型亲本菌株相比，CAT1菌株在葡萄糖存在下生长增加，但在苯并芘存在下生长在统计学上有显著下降。此外，我们证明Csr系统对其表达有正向调节作用，因为观察到突变菌株LYA12（M2-7 csrA::Sp, SpR）中该基因的表达明显低于野生型菌株。因此，我们能够提出在苯并芘存在的情况下，CsrA调节因子对地衣芽孢杆菌M2-7菌株中catE基因的一种假定调节模型。
