Influence of dietary catechols on the growth of enteropathogenic bacteria
Influence of dietary catechols on the growth of enteropathogenic bacteria
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DOI：
10.1016/j.ijfoodmicro.2007.07.039
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发表时间：
2007-11-01
影响因子：
5.4
通讯作者：
Lyte, Mark
中科院分区：
文献类型：
--
作者：
Freestone, Primrose P. E.;Walton, Nicholas J.;Lyte, Mark
从最广泛的意义上说，可能作为辅助因子使细菌性肠道病原体在胃肠道环境中复制的饮食成分仍然是未知的。最近的研究表明，食物中的某些非营养成分，如儿茶酚胺，可以促进革兰氏阴性病原体在可能反映胃肠道环境的铁限制性介质中复制的能力。本报告探讨是否其他，非儿茶酚胺，膳食儿茶酚，广泛存在于植物性食品，也可以影响肠道病原体的生长在铁限制性的环境，如可能会发现在胃肠道。在本研究中，我们研究了一系列富含儿茶酚的食品，从饮料（茶和咖啡）水果和蔬菜提取物，以及纯化制剂的常用食用儿茶酚（儿茶素，绿原酸，咖啡酸和单宁酸），调节革兰氏阴性肠道病原体大肠杆菌O 15：H7和沙门氏菌肠道SV Enteriditis的生长的能力。在铁充足的富培养基以及铁限制的基础培养基中检测了响应于饮食儿茶酚（0.05- 5.0%v/v的饮料或水果/蔬菜提取物; 10-200 μ M的纯化儿茶酚）的时间依赖性生长，所述铁限制的基础培养基设计成反映更具有人类和动物组织特征的铁限制环境。在含铁丰富的培养基中获得的结果证明了对邻苯二酚的剂量依赖性抑菌作用，与先前的研究一致。然而，在铁限制培养基中，所有的饮食儿茶酚产生显着的生长刺激高达4个对数大于非补充对照。在存在或不存在膳食儿茶酚的情况下生长的细菌中，测量从Fe-55标记的乳铁蛋白和转铁蛋白中摄取放射性标记的Fe-55的机制研究表明，儿茶酚刺激细菌生长的能力取决于从铁螯合糖蛋白中提供铁。尿素凝胶分析转铁蛋白孵育的存在下，膳食儿茶酚证实，这些化合物直接螯合和去除转铁蛋白复合。铁.用E. coli O 157：H7 entA和tonB突变体进一步表明，生长刺激反应需要功能性铁载体合成和摄取系统。与先前报道了膳食儿茶酚的抗微生物活性的研究相反，本研究表明，在铁限制条件下，食物中的这些非营养成分可以提供铁并使肠道细菌病原体生长。(C)2007 Elsevier B. V.保留所有权利。
The dietary constituents that may act, in the broadest sense, as co-factors to enable bacterial enteropathogens to replicate in gastrointestinal environments are still largely unknown. Recent work has demonstrated that certain non-nutritional components of food, such as the catecholamines, can contribute to the ability of Gram-negative pathogens to replicate in iron-restrictive media that may be reflective of gastrointestinal environments. The present report examines whether other, non-catecholamine, dietary catechols, which occur widely in plant foods, can also influence enteropathogen growth in an iron-restrictive environment such as might be found in the gastrointestinal tract. In the present study, we have examined the ability of a range of catechol-rich foodstuffs, ranging from beverages (tea and coffee) to fruit and vegetable extracts, as well as purified preparations of commonly consumed dietary catechols (catechins, chlorogenic acid, caffeic acid and tannic acid), to modulate the growth of the Gram-negative enteric pathogens Escherichia coli O15:H7 and Salmonella enterica SV Enteriditis. Time-dependent growth in response to dietary catechols (0.05-5.0% v/v of beverage or fruit/vegetable extracts; 10-200 mu M of purified catechols) was examined in an iron-replete, rich medium as well as in an iron-limited, basal medium designed to reflect the iron-restricted environment that is more characteristic of human and animal tissues. Results obtained in iron-replete, rich medium demonstrated dose-dependent bacteriostatic effects to am catechols, consistent with previous studies. However, in iron-restricted medium, all of the dietary catechols produced marked growth stimulation of up to 4 logs greater than non-supplemented controls. Mechanistic studies measuring the uptake of radiolabelled Fe-55 from Fe-55 labelled lactoferrin and transferrin in bacteria grown in the presence or absence of dietary catechols demonstrated that the ability of catechols to stimulate bacterial growth was dependent on the provision of iron from iron-sequestering glycoproteins. Urea gel analysis of transferrin incubated in the presence of the dietary catechols confirmed that these compounds were directly chelating and removing transferrin-complexed. iron. Analysis using E. coli O157:H7 entA and tonB mutants further showed that a functional siderophore synthesis and uptake system was required for the growth-stimulatory response. In contrast to previous studies, which have reported the anti-microbial activity of dietary catechols, the present study demonstrates that these non-nutritional components of foods can, under iron-restrictive conditions, provide iron and enable the growth of enteric bacterial pathogens. (C) 2007 Elsevier B.V. All rights reserved.