Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA.
Appl Environ Microbiol. 2013 Nov;79(22):6855-61. doi: 10.1128/AEM.01006-13. Epub 2013 Aug 23.
A study to determine the attachment of L. monocytogenes serotype 4b strain F2365 on vegetables and fruits was conducted. In an initial study, we screened 32 genes encoding surface proteins and lipases of the strain to find highly expressed genes on lettuce leaves. The results showed that transcription levels of LMOf2365_0413, LMOf2365_0498, LMOf2365_0859, LMOf2365_2052, and LMOf2365_2812 were significantly upregulated on lettuce leaves. In silico analysis showed that LMOf2365_0859 contains a putative cellulose binding domain. Thus, we hypothesized that this gene may be involved in an attachment to vegetables, and named it lcp (gene encoding Listeria cellulose binding protein [LCP]). lcp mutant (Δlcp) and lcp complement (F2365::pMAD::cat::lcp) strains were generated by homologous recombination. The abilities of a wild-type (WT) strain, the Δlcp strain, and the complemented strain to attach to lettuce leaves were evaluated, which indicated that the attachment of the Δlcp strain to lettuce was significantly less than that of the WT and the complemented strains. Similar results were observed for baby spinach and cantaloupe. Fluorescence microscopy and field emission scanning microscopy analysis further supported these findings. The binding of L. monocytogenes to cellulose was determined using cellulose acetate-coated plates. The results showed that a binding ability of the Δlcp strain was significantly lower than that of the wild type. Combined, these results strongly suggest that LCP plays an important role in an attachment to vegetables and fruits.
一项旨在确定李斯特菌 4b 血清型 F2365 菌株在蔬菜和水果上附着的研究。在初步研究中，我们筛选了该菌株编码表面蛋白和脂肪酶的 32 个基因，以找到在生菜叶片上高度表达的基因。结果表明，LMOf2365_0413、LMOf2365_0498、LMOf2365_0859、LMOf2365_2052 和 LMOf2365_2812 的转录水平在生菜叶片上显著上调。计算机分析表明，LMOf2365_0859 含有一个假定的纤维素结合结构域。因此，我们假设该基因可能参与与蔬菜的附着，并将其命名为 lcp（编码李斯特菌纤维素结合蛋白 [LCP] 的基因）。通过同源重组生成 lcp 突变体（Δlcp）和 lcp 互补（F2365::pMAD::cat::lcp）菌株。评估了野生型（WT）菌株、Δlcp 菌株和互补菌株附着在生菜叶片上的能力，结果表明，Δlcp 菌株对生菜的附着能力明显低于 WT 和互补菌株。在婴儿菠菜和哈密瓜上也观察到了类似的结果。荧光显微镜和场发射扫描显微镜分析进一步支持了这些发现。使用醋酸纤维素涂层板测定了李斯特菌与纤维素的结合能力。结果表明，Δlcp 菌株的结合能力明显低于野生型。综合这些结果强烈表明，LCP 在与蔬菜和水果的附着中起重要作用。
