Planchon Stella, Desvaux Mickaël, Chafsey Ingrid, Chambon Christophe, Leroy Sabine, Hébraud Michel, Talon Régine
INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France.
J Proteome Res. 2009 Apr;8(4):1797-809. doi: 10.1021/pr8004056.
Staphylococcus xylosus is a Gram-positive bacterium found on the skin of mammals and frequently isolated from food plants and fermented cheese or meat. To gain further insight in protein determinants involved in biofilm formation by this coagulase-negative Staphylococcus, a comparative proteomic analysis between planktonic and sessile cells was performed. With the use of a protocol previously developed, protein patterns of the cytoplasmic and cell envelope fractions were compared by 2-DE. Following protein identification by MALDI-TOF mass spectrometry and bioinformatic analyses, this study revealed differences in expression levels of 89 distinct proteins with 55 up-expressed and 34 down-expressed proteins in biofilm compared to planktonic cells. Most proteins differentially expressed were related to nitrogen and carbon metabolisms. Besides amino acid biosynthesis and protein translation, protein determinants related to protein secretion were up-expressed in biofilm, suggesting a more active protein trafficking in sessile cells. While up-expression of several enzymes involved in pentose phosphate and glycolytic pathways was observed in biofilm, connections with unexpected metabolic routes were further unravelled. Indeed, this proteomic analysis allowed identifying novel proteins that could be involved in a previously uncovered exopolysaccharide biosynthetic pathway in S. xylosus as well as several enzymes related to polyketide biosynthesis. This findings are particularly relevant considering exopolysaccharide production in S. xylosus is ica-independent contrary to coagulase-negative model strain Staphylococcus epidermidis RP62A.
木糖葡萄球菌是一种革兰氏阳性菌，存在于哺乳动物的皮肤上，经常从食用植物、发酵奶酪或肉类中分离出来。为了进一步深入了解这种凝固酶阴性葡萄球菌生物膜形成过程中的蛋白质决定因素，对浮游细胞和固着细胞进行了比较蛋白质组学分析。使用先前开发的方案，通过二维电泳比较细胞质和细胞包膜组分的蛋白质模式。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）和生物信息学分析进行蛋白质鉴定后，本研究揭示了89种不同蛋白质的表达水平差异，与浮游细胞相比，生物膜中有55种蛋白质表达上调，34种蛋白质表达下调。大多数差异表达的蛋白质与氮和碳代谢有关。除了氨基酸生物合成和蛋白质翻译外，与蛋白质分泌相关的蛋白质决定因素在生物膜中表达上调，这表明固着细胞中的蛋白质运输更为活跃。虽然在生物膜中观察到参与磷酸戊糖途径和糖酵解途径的几种酶表达上调，但与意外代谢途径的联系进一步被揭示。事实上，这种蛋白质组学分析能够鉴定出可能参与木糖葡萄球菌中先前未发现的胞外多糖生物合成途径的新蛋白质，以及几种与聚酮化合物生物合成相关的酶。考虑到与凝固酶阴性模式菌株表皮葡萄球菌RP62A不同，木糖葡萄球菌的胞外多糖产生不依赖ica，这些发现尤为重要。
