Talwalkar Akshat, Kailasapathy Kaila
Centre for Advanced Food Research, University of Western Sydney, Locked Bag 1797, SPDC, NSW 1797, Australia.
Curr Issues Intest Microbiol. 2004 Mar;5(1):1-8.
The various therapeutic benefits of Lactobacillus acidophilus and Bifidobacterium spp. have resulted in their increased incorporation into dairy foods such as yoghurts. Currently however, the efficacy of these probiotic bacteria is limited by their poor survival during the shelf life of yoghurt. Oxygen toxicity is widely considered to be responsible for the cell deaths of these bacteria. The intestinal origins and the microaerophilic and anaerobic characteristics of L. acidophilus and Bifidobacterium spp. respectively, can render them susceptible to oxygen contained in the food products. This review discusses the influence of the dissolved oxygen in yogurt on the viability of these bacteria. Suggested techniques to protect these probiotic bacteria from oxygen toxicity are evaluated. Although the problem of oxygen toxicity in probiotic bacteria is regarded as significant, little is known however about the cellular interaction of these bacteria with oxygen. This review summarizes what is known about the biochemistry of oxygen toxicity in these bacteria. The various metabolic and biochemical responses of L. acidophilus and Bifidobacterium to oxygen are examined. Additionally, the importance of NADH oxidase and NADH peroxidase in the oxygen tolerance of these bacteria is evaluated and assays used to measure their cellular concentrations are discussed.
嗜酸乳杆菌和双歧杆菌属的多种治疗益处促使它们更多地被添加到酸奶等乳制品中。然而目前，这些益生菌在酸奶保质期内的存活率较低，限制了它们的功效。人们普遍认为氧毒性是导致这些细菌细胞死亡的原因。嗜酸乳杆菌和双歧杆菌属分别起源于肠道，具有微需氧和厌氧特性，这使得它们易受食品中所含氧气的影响。本文综述了酸奶中溶解氧对这些细菌活力的影响。评估了保护这些益生菌免受氧毒性影响的建议技术。尽管益生菌中的氧毒性问题被认为很严重，但关于这些细菌与氧的细胞相互作用却知之甚少。本文总结了已知的这些细菌中氧毒性的生物化学知识。研究了嗜酸乳杆菌和双歧杆菌对氧的各种代谢和生化反应。此外，评估了NADH氧化酶和NADH过氧化物酶在这些细菌耐氧性中的重要性，并讨论了用于测量它们细胞浓度的测定方法。
