Identification and Characterization of Extracellular Cyclic Dipeptides As Quorum-Sensing Signal Molecules from Shewanella baltica, the Specific Spoilage Organism of Pseudosciaena crocea during 4 °C Storage
Identification and Characterization of Extracellular Cyclic Dipeptides As Quorum-Sensing Signal Molecules from Shewanella baltica, the Specific Spoilage Organism of Pseudosciaena crocea during 4 °C Storage
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DOI：
10.1021/jf403918x
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发表时间：
2013-11-27
影响因子：
6.1
通讯作者：
Lin, Junda
中科院分区：
文献类型：
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作者：
Gu, Qingqing;Fu, Linglin;Lin, Junda
群体感应（QS）信号分子能够介导腐败细菌内特定基因的表达，从而响应于群体密度，因此与食品腐败有关。从4 ℃贮藏的大黄鱼中分离到102株腐败菌，经鉴定为希瓦氏菌属60株，48株（47.1%）为S.波罗的海。此外，还比较了三种不同S.通过总挥发性盐基氮（TVB-N）和感官分析（异味）比较波罗的海（baltica）菌株（00 A、00 B和00 C）。此外，四个环二肽（diketopiperazines，DKPs）的功能作为QS信号分子分离和表征的胞外代谢物的S。通过气相色谱-质谱联用（GC-MS）分析，发现波罗的海00 C的腐败活性最强。通过添加四种合成的DKP，S.波罗的海可以大大加强。到目前为止，这是首次尝试将DKPs表征为S.波罗的海。我们的研究可能会提供一些证据的作用，DKP参与微生物腐败。
Quorum-sensing (QS) signaling molecules are able to mediate specific gene expression inside spoilage bacteria in response to population density and thus are implicated in food spoilage. In the present work, a total of 102 strains of spoilage bacteria were isolated from Pseudosciaena crocea at 4 degrees C storage, and of these, 60 strains were identified as Shewanella spp., and 48 strains (47.1%) were identified as S. baltica. In addition, the spoilage capabilities of three different S. baltica strains (00A, 00B, and 00C) were compared by total volatile base nitrogen (TVB-N) and sensory analysis (off-odors). Furthermore, four cyclic dipeptides (diketopiperazines, DKPs) that function as QS signal molecules were isolated and characterized from the extracellular metabolites of S. baltica 00C which had the strongest spoilage activity based on gas chromatography mass spectrometry (GC-MS). By supplementation of four synthesized DKPs, the spoilage capability of S. baltica could be significantly enhanced. So far, this was the first attempt to characterize DKPs as the signaling molecules in QS of S. baltica. Our study may provide some evidence of the role of DKPs involved in microbial spoilage.