保加利亚乳酸杆菌分解多种尿毒素的定向诱变

Directed mutagenesis of lactobacillus bulgaricus for decomposition of uremic toxins

目的选育一株能分解多种尿毒素的益生菌为慢性肾衰的肠道细菌疗法提供新菌种。方法原始保加利亚乳酸杆菌先经尿毒症患者血清诱导培养,后用物理(紫外线)和化学(硫酸二乙酯)双重多次诱变方法对其进行诱变,以肌酐分解率为观察指标,筛选出具有高效分解肌酐的乳酸菌,测定其遗传稳定性并观察其对尿素氮、尿酸、血磷、甲状旁腺素、同型半胱氨酸的分解能力。结果从大量突变株中选育出一株高效分解尿毒素的菌株DUC3-17,其肌酐、尿素氮、尿酸、血磷、甲状旁腺素、同型半胱氨酸的分解率为17.23%,36.02%,9.84%,15.73%,78.26%,12.69%。经5次传代其分解力仍稳定。原始菌株不具有分解上述毒素的能力。结论运用尿毒症患者血清定向诱导后经硫酸二乙酯-紫外线复合诱变的方法,成功获得一株高效分解多种尿毒素的保加利亚乳酸工程菌,其尿毒素分解力能够稳定遗传。

Objective We aimed to obtain a strain of probiotics from lactobacillus bulgaricus capable to decompose uremic toxins, to provide a new strain of intestinal bacterium for the treatment of chronic renal failure. Method The original lactobacillus bulgaricus was induced by incubation in uremic patients＇ sera, and then repeatedly induced by physical （ultraviolet radiation） and chemical （diethyl sulfate） methods. We used the decomposition ability to creatinine as the index, to select the strains capable to efficiently decompose creatinine, and then to test their genetic stability and their decomposition abilities to urea, uric acid, serum phosphate, parathyroid hormone, and homocysteine. Result After the inductive and mutagenic treatments, we obtained a strain of DUC3-17. The decomposition rates of this strain for creatinine, urea nitrogen, uric ac- id, phosphorus, parathyroid hormone and homocysteine were 17.23%, 36.02%, 9.84%, 15.73%, 78.26%, and 12.69%, respectively. These abilities were stable after 5 passages. The original lactobacillus bulgaricus did not have these abilities. Conclusion We used directed induction and physical and chemical methods to lactoba- cillus bulgaricus, and obtained a mutant strain that has greater abilities to decompose uremic toxins and was genetically stable.