水稻根际耐镉细菌碳源代谢功能分析

为探明前期分离得到的3株水稻根际耐镉细菌碳源代谢特性,在进行生理生化鉴定的基础上,采用BIOLOG ECO微平板法,分析了3株细菌(菌株A、菌株B和菌株C)的碳源代谢功能。生理生化试验结果表明,3株菌均属于革兰氏阴性细菌,且均具有极生鞭毛,菌株C的生理生化鉴定为铜绿假单胞菌,菌株A与菌株B为假单胞菌属的其他种,结果与之前的分子生物学鉴定结果一致。BIOLOG分析结果表明,3株菌株在培养72 h的AWCD(平均颜色变化率)均接近最大值,在培养24 h时的AWCD存在显著差异,这种差异主要体现在对氨基酸的利用上。在对提供的31种单一碳源利用上,3株菌对N-乙酰-D-葡萄糖胺、L-精氨酸、L-天冬酰胺、甲叉丁二酸、腐胺、4-羟基苯甲酸、丙酮酸甲酯、吐温-40和吐温-80的利用率均较高,且对L-精氨酸、甲叉丁二酸、丙酮酸甲酯的利用率存在显著差异。本研究结果对深入了解耐镉菌株增殖所需要的碳源以及将来优化耐镉细菌最适培养基提供了理论依据,也为构建相应的基因工程菌提供了微生物资源。

Analysis of carbon source metabolism functions of cadmium-tolerantbacteria separated from rice (Oryza satiua) rhizosphere

To understand metabolic abilities of carbon sources in three cadmium-tolerant bacteria (strain A, strain B and strain C) isolated from rice rhizosphere soils, basic characteristics of bacteria strains were determined by physiological and biochemical reactions and metabolic functions of carbon sources analyzed via the BIOLOG ECO plate method. The main principle was based on the fact that color-reduction reaction showed differences in carbon source utilization. The physiological and biochemical characteristics showed that all three bacteria strains behaved as Gram-negative with born flagellum. Strain C was identified as Pseudomonas aeruginosa, while strains A and B both belonged to different Pseudomonas species. The conclusions on physiological and biochemical characteristics were the same as in previous molecular identifications. BIOLOG ECO analysis showed that average well color development (AWCD) nearly approached the maximum after culturing the strains for 72 hours. Significant differences were noted in AWCD among cultured strains for 24 hours, dominated by amino acid utilization efficiency. Among the thirty-one single carbon sources used, higher utilization rates were noted in nine compounds. The compounds included N-Acetyl-D- glucosamine, L-Arginine, L-Asparagine, Itaconic acid, Putrescicine, 4-Hydroxy benzoic acid, Pyruvic acid methyl ester, Tween 40 and Tween 80. Also significant differences were detected among the three bacteria strains regarding utilization rates of L-Arginine, Itaconic acid and Pyruvic acid methyl ester. On the basis of carbon source utilization, more information was gathered on strain functions. Thus this study expanded our knowledge on needed carbon sources for cadmium-tolerant strain growth. The study also taught us optimization strategy of cultured media which was beneficial for future research work. Furthermore, it provided precious microorganism resources for constructing corresponding bacteria gene engineering.