State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2010;22(2):168-75. doi: 10.1016/s1001-0742(09)60089-9.
A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR (MC-RR) at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.
从中国滇池中分离到的一株菌株 USTB-05，以 16.7mg/L/天的速度降解微囊藻毒素 RR（MC-RR）。16S rDNA 序列分析表明，该菌株为鞘氨醇单胞菌属。鉴定了鞘氨醇单胞菌属 USTB-05 对 MC-RR 的酶促降解途径。MC-RR 的 Adda-Arg 肽键被切断，然后 Adda 的氨基和精氨酸的羧基上各加上一个氢和一个羟基，形成中间产物，在最初的几个小时内。然后，通过脱水反应，精氨酸上氨基的两个氢与相邻碳原子上的羟基反应，形成一条线性 MC-RR，其中两条小肽环作为最终产物在 24 小时后形成。这些生物降解途径与其他菌株报道的途径不同，这表明由于天然湖泊和水库中的各种细菌，MC-RR 可能经历不同的转化，形成不同的产物。
