Sleator R D, Wouters J, Gahan C G, Abee T, Hill C
Department of Microbiology and National Food Biotechnology Centre, University College, Cork, Ireland.
Appl Environ Microbiol. 2001 Jun;67(6):2692-8. doi: 10.1128/AEM.67.6.2692-2698.2001.
The success of Listeria monocytogenes as a food-borne pathogen owes much to its ability to survive a variety of stresses, both in the external environment prior to ingestion and subsequently within the animal host. Growth at high salt concentrations and low temperatures is attributed mainly to the accumulation of organic solutes such as glycine betaine and carnitine. We utilized a novel system for generating chromosomal mutations (based on a lactococcal pWVO1-derived Ori(+) RepA(-) vector, pORI19) to identify a listerial OpuC homologue. Mutating the operon in two strains of L. monocytogenes revealed significant strain variation in the observed activity of OpuC. Radiolabeled osmolyte uptake studies, together with growth experiments in defined media, linked OpuC to carnitine and glycine betaine uptake in Listeria. We also investigated the role of OpuC in contributing to the growth and survival of Listeria in an animal (murine) model of infection. Altering OpuC resulted in a significant reduction in the ability of Listeria to colonize the upper small intestine and cause subsequent systemic infection following peroral inoculation.
单核细胞增生李斯特菌作为一种食源性病原体，其成功很大程度上归功于它在多种压力下存活的能力，无论是在摄入前的外部环境中，还是随后在动物宿主体内。在高盐浓度和低温下生长主要归因于有机溶质如甘氨酸甜菜碱和肉碱的积累。我们利用一种新型的产生染色体突变的系统（基于源自乳球菌pWVO1的Ori(+)RepA(-)载体pORI19）来鉴定李斯特菌的OpuC同源物。在两株单核细胞增生李斯特菌中对该操纵子进行突变，结果显示OpuC的观察活性存在显著的菌株差异。放射性标记的渗透溶质摄取研究以及在限定培养基中的生长实验表明，OpuC与李斯特菌中肉碱和甘氨酸甜菜碱的摄取有关。我们还研究了OpuC在动物（小鼠）感染模型中对李斯特菌生长和存活的作用。改变OpuC导致李斯特菌在经口接种后定殖于小肠上段并引起随后全身感染的能力显著降低。
