Food-bacteria interplay: pathometabolism of emetic Bacillus cereus.
Food-bacteria interplay: pathometabolism of emetic Bacillus cereus.
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DOI：
10.3389/fmicb.2015.00704
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发表时间：
2015
影响因子：
5.2
通讯作者：
Gohar M
中科院分区：
文献类型：
--
作者：
Ehling-Schulz M;Frenzel E;Gohar M
蜡样芽孢杆菌是一种革兰氏阳性内生孢子形成细菌，以其广泛的表型特征而闻名，使其能够占据不同的生态位。虽然B.催吐剂B的产生是高度动态的，而且是随机的。蜡状菌毒素催泪素仅限于与不同环境生境相关的具有特定基因型特征的菌株。Cereulide是一种离子型十二肽，由一种具有不寻常模块结构的酶复合物非核糖体产生，称为Cereulide合成酶（Ces非核糖体肽合成酶）。ces基因座在与B相关的巨毒力质粒上编码。炭疽毒素质粒pXO 1。Cereulide是一种高度耐热和耐pH的分子，在食物中形成，在摄入后几小时引起呕吐，并且被证明是胃肠炎症状的直接原因;偶尔它涉及严重的临床表现，包括急性肝衰竭。催吐剂B中毒素基因表达的调控。蜡状芽孢杆菌的毒素基因表达涉及到中央转录调节因子，如CodY和AbrB，从而将毒素基因表达与生命周期阶段和特定条件（如食物基质中遇到的营养供应）密不可分地联系起来。虽然近年来在催泪素毒素合成的分子和生化表征方面取得了相当大的进展，但对毒素合成在B生命周期中的嵌入知之甚少。蜡状。缺乏关于食物环境中毒素产生信号的信息。本文综述了催吐B中催吐素毒素合成的复杂调控网络，讨论了催吐素毒素合成的内在和外在因素。并强调如何解开这些过程可以导致新的有效战略，以防止毒素合成的食品生产和加工链的发展。
Bacillus cereus is a Gram-positive endospore forming bacterium known for its wide spectrum of phenotypic traits, enabling it to occupy diverse ecological niches. Although the population structure of B. cereus is highly dynamic and rather panmictic, production of the emetic B. cereus toxin cereulide is restricted to strains with specific genotypic traits, associated with distinct environmental habitats. Cereulide is an ionophoric dodecadepsipeptide that is produced non-ribosomally by an enzyme complex with an unusual modular structure, named cereulide synthetase (Ces non-ribosomal peptide synthetase). The ces gene locus is encoded on a mega virulence plasmid related to the B. anthracis toxin plasmid pXO1. Cereulide, a highly thermo- and pH- resistant molecule, is preformed in food, evokes vomiting a few hours after ingestion, and was shown to be the direct cause of gastroenteritis symptoms; occasionally it is implicated in severe clinical manifestations including acute liver failures. Control of toxin gene expression in emetic B. cereus involves central transcriptional regulators, such as CodY and AbrB, thereby inextricably linking toxin gene expression to life cycle phases and specific conditions, such as the nutrient supply encountered in food matrices. While in recent years considerable progress has been made in the molecular and biochemical characterization of cereulide toxin synthesis, far less is known about the embedment of toxin synthesis in the life cycle of B. cereus. Information about signals acting on toxin production in the food environment is lacking. We summarize the data available on the complex regulatory network controlling cereulide toxin synthesis, discuss the role of intrinsic and extrinsic factors acting on toxin biosynthesis in emetic B. cereus and stress how unraveling these processes can lead to the development of novel effective strategies to prevent toxin synthesis in the food production and processing chain.