Sun Jinchun, Jin Jinshan, Beger Richard D, Cerniglia Carl E, Chen Huizhong
Division of Systems Biology, National Center for Toxicological Research, US FDA, 3900 NCTR Rd, Jefferson, AR, 72079-9502, USA.
Division of Microbiology, National Center for Toxicological Research, US FDA, 3900 NCTR Rd, Jefferson, AR, 72079-9502, USA.
J Ind Microbiol Biotechnol. 2017 Oct;44(10):1471-1481. doi: 10.1007/s10295-017-1970-8. Epub 2017 Aug 7.
Dyes containing one or more azo linkages are widely applied in cosmetics, tattooing, food and drinks, pharmaceuticals, printing inks, plastics, leather, as well as paper industries. Previously we reported that bacteria living on human skin have the ability to reduce some azo dyes to aromatic amines, which raises potential safety concerns regarding human dermal exposure to azo dyes such as those in tattoo ink and cosmetic colorant formulations. To comprehensively investigate azo dye-induced toxicity by skin bacteria activation, it is very critical to understand the mechanism of metabolism of the azo dyes at the systems biology level. In this study, an LC/MS-based metabolomics approach was employed to globally investigate metabolism of azo dyes by Staphylococcus aureus as well as their effects on the metabolome of the bacterium. Growth of S. aureus in the presence of Sudan III or Orange II was not affected during the incubation period. Metabolomics results showed that Sudan III was metabolized to 4-(phenyldiazenyl) aniline (48%), 1-[(4-aminophenyl) diazenyl]-2-naphthol (4%) and eicosenoic acid Sudan III (0.9%). These findings indicated that the azo bond close to naphthalene group of Sudan III was preferentially cleaved compared with the other azo bond. The metabolite from Orange II was identified as 4-aminobenzene sulfonic acid (35%). A much higher amount of Orange II (~90×) was detected in the cell pellets from the active viable cells compared with those from boiled cells incubated with the same concentration of Orange II. This finding suggests that Orange II was primarily transported into the S. aureus cells for metabolism, instead of the theory that the azo dye metabolism occurs extracellularly. In addition, the metabolomics results showed that Sudan III affected energy pathways of the S. aureus cells, while Orange II had less noticeable effects on the cells. In summary, this study provided novel information regarding azo dye metabolism by the skin bacterium, the effects of azo dyes on the bacterial cells and the important role on the toxicity and/or inactivation of these compounds due to microbial metabolism.
含有一个或多个偶氮键的染料广泛应用于化妆品、纹身、食品饮料、制药、印刷油墨、塑料、皮革以及造纸工业。此前我们报道过，生活在人体皮肤上的细菌能够将一些偶氮染料还原为芳香胺，这引发了人们对人体皮肤接触偶氮染料（如纹身油墨和化妆品着色剂配方中的偶氮染料）的潜在安全担忧。为了通过皮肤细菌激活全面研究偶氮染料诱导的毒性，在系统生物学水平上了解偶氮染料的代谢机制至关重要。在本研究中，采用基于液相色谱/质谱的代谢组学方法全面研究金黄色葡萄球菌对偶氮染料的代谢及其对该细菌代谢组的影响。在孵育期间，金黄色葡萄球菌在苏丹III或橙黄II存在下的生长未受影响。代谢组学结果表明，苏丹III被代谢为4-（苯基重氮基）苯胺（48%）、1-[(4-氨基苯基)重氮基]-2-萘酚（4%）和二十碳烯酸苏丹III（0.9%）。这些发现表明，与苏丹III的另一个偶氮键相比，靠近萘基团的偶氮键优先断裂。橙黄II的代谢产物被鉴定为4-氨基苯磺酸（35%）。与用相同浓度橙黄II孵育的煮沸细胞相比，在活性活细胞的细胞沉淀中检测到的橙黄II量要高得多（约90倍）。这一发现表明，橙黄II主要被转运到金黄色葡萄球菌细胞内进行代谢，而不是偶氮染料代谢发生在细胞外的理论。此外，代谢组学结果表明，苏丹III影响金黄色葡萄球菌细胞的能量途径，而橙黄II对细胞的影响较小。总之，本研究提供了关于皮肤细菌对偶氮染料代谢、偶氮染料对细菌细胞的影响以及微生物代谢对这些化合物毒性和/或失活的重要作用的新信息。
