Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia.
Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia.
Ecotoxicol Environ Saf. 2019 May 30;173:373-380. doi: 10.1016/j.ecoenv.2019.02.045. Epub 2019 Feb 20.
Glyphosate-based herbicides (GBHs) are the most widespread commonly used broad-spectrum herbicides that contaminate soils and waters, are toxic to bacteria, plants and animals, and have been classified as 'probably carcinogenic to humans' by the International Agency for Research on Cancer in 2015. Particular soil bacteria and fungi can degrade GBHs, hence, search for new GBH-degrading strains or microbial consortia, effective under specific growth conditions and local environment, seems to be a promising solution for bio-remediation of glyphosate-contaminated environment. Consequently, there is a need for rapid and informative methods to evaluate the GBH-induced changes of the metabolic pathways in cells, that may serve as indicators of GBH-degrading potential. Three new GBH-degrading bacterial strains, Pseudomonas sp., Actinobacteria and Serratia sp. were isolated from sludge of municipal waste water treatment plant (Daugavgriva, Riga, Latvia), agricultural soil and plant tissue, respectively. This study examined the response of these isolates to elevated concentrations of glyphosate (GLP) (100 and 500 mg/L) in GBH Klinik® 360 SL. The GBH-induced shift of metabolic activity in cells of Pseudomonas sp. was shown by tests on EcoPlates™. Fourier transform infrared (FTIR) spectroscopy analyses were used to evaluate the metabolomic response of bacteria to elevated concentrations of GBH in the growth environment. The spectra of Pseudomonas sp. and Serratia sp., incubated with and without GBH, were similar, thus indicating their GBH-resistance. The absorption at 1736 cm, assigned to ester carbonyl stretch vibrations, was detected in spectra of all three bacteria. The highest ester content was detected in Actinobacteria grown in medium with 1.0% molasses and 100 or 500 mg/L GLP in GBH Klinik®. An increase of cellular amounts of esters, either those of phospholipids or poly-β-hydroxybutyrates, indicates degradation of GLP. Therefore, monitoring the ester carbonyl stretch vibration band in FTIR spectra of bacterial biomass may speed up the search GBH-degrading strains. Microbiological tests and cell metabolic response studies by FTIR spectroscopy showed that the three new isolates of Pseudomonas sp., Actinobacteria and Serratia sp. were resistant to elevated concentrations of GBH Klinik® in growth environment and exhibited the potential for GBH degradation.
草甘膦基除草剂（GBHs）是最广泛使用的广谱除草剂，会污染土壤和水，对细菌、植物和动物有毒，并且在 2015 年被国际癌症研究机构归类为“可能对人类致癌”。特定的土壤细菌和真菌可以降解 GBHs，因此，寻找在特定生长条件和当地环境下有效的新的 GBH 降解菌株或微生物群落，似乎是生物修复草甘膦污染环境的一种有前途的方法。因此，需要快速且信息量丰富的方法来评估细胞中草甘膦诱导的代谢途径变化，这些变化可以作为草甘膦降解潜力的指标。从市政废水处理厂（拉脱维亚里加的道加瓦河）的污泥、农业土壤和植物组织中分别分离到了三种新的草甘膦降解细菌菌株，分别为假单胞菌、放线菌和沙雷氏菌。本研究检测了这些分离株对 Klinik®360 SL 草甘膦（GLP）（100 和 500mg/L）升高浓度的反应。通过 EcoPlates™测试显示了假单胞菌中草甘膦诱导的代谢活性变化。傅里叶变换红外（FTIR）光谱分析用于评估细菌在生长环境中对草甘膦升高浓度的代谢组响应。在有和没有草甘膦的情况下孵育的假单胞菌和沙雷氏菌的光谱相似，因此表明它们对草甘膦具有抗性。在所有三种细菌的光谱中都检测到了 1736cm 处的吸收峰，该峰被分配到酯羰基伸缩振动。在 1.0% 糖蜜和 100 或 500mg/L GLP 的 Klinik®中生长的放线菌中检测到的酯含量最高。细胞中酯的含量增加，无论是磷脂酯还是聚-β-羟基丁酸酯，都表明 GLP 的降解。因此，在 FTIR 光谱中监测细菌生物量的酯羰基伸缩振动带可能会加速对草甘膦降解菌株的搜索。微生物测试和 FTIR 光谱的细胞代谢反应研究表明，三种新的假单胞菌、放线菌和沙雷氏菌分离株在生长环境中对 Klinik®草甘膦的升高浓度具有抗性，并表现出草甘膦降解的潜力。
