Alterations in the formation of lipopolysaccharide and membrane vesicles on the surface of Pseudomonas aeruginosa PAO1 under oxygen stress conditions
Alterations in the formation of lipopolysaccharide and membrane vesicles on the surface of Pseudomonas aeruginosa PAO1 under oxygen stress conditions
复制标题
DOI：
10.1099/mic.0.26443-0
复制
发表时间：
2003-10-01
期刊：
影响因子：
2.8
通讯作者：
Zeng, AP
中科院分区：
文献类型：
--
作者：
Sabra, W;Lünsdorf, H;Zeng, AP
据推测，铜绿假单胞菌中两种化学上不同类型的脂多糖（LPS），即一种细菌型特异性LPS（B带）和一种共同抗原LPS（A带）的相对表达的表型变异是一种重要的机制，使这种机会致病菌能够改变其表面特征以介导粘附并在极端条件下存活。为了进一步研究这一点，用在恒化器中在不同溶解氧张力（pO（2））下生长的细胞研究了铜绿假单胞菌PAO 1中两种不同类型的LPS的相对表达水平。当pO（2）从接近0增加到空气饱和度的350%时，A带LPS组成性表达。相反，B带LPS随pO（2）增加而显著增加。在pO（2）低于空气饱和度3%的条件下生长的细胞中几乎没有发现B带LPS。细胞的电子显微镜检查显示，在氧应激条件下，铜绿假单胞菌PAO 1表面膜囊泡（MV）的形成增加。铜绿假单胞菌培养物上清液对杂交瘤细胞系生长的毒性在从氧应激稳态培养物中采集的样品中显著增加。此外，连续流动生物膜培养物中的粘附研究揭示了在较高pO下生长的铜绿假单胞菌PAO 1中亲水表面的粘附性增加（2），这项工作中观察到的细胞表面组分和性质的氧依赖性改变为慢性感染的囊性纤维化患者中缺乏B带LIPS的铜绿假单胞菌的出现提供了可能的解释。这些结果也有助于理解铜绿假单胞菌中MV形成的过程。
It has been postulated that phenotypic variation in the relative expression of two chemically distinct types of lipopolysaccharide (LPS), a serotype-specific LPS (B-band) and a common antigen LPS (A-band) in Pseudomonas aeruginosa is an important mechanism enabling this opportunistic pathogen to alter its surface characteristics to mediate adhesion and to survive under extreme conditions. To further investigate this, the relative expression levels of the two distinct types of LPS in P. aeruginosa PAO1 were investigated with cells grown in a chemostat at different dissolved oxygen tensions (pO(2)). The A-band LPS was constitutively expressed as pO(2) was increased from nearly zero to 350% of air saturation. In contrast, the B-band LPS showed a remarkable increase with increased pO(2). Almost no B-band LPS was found in cells grown at a pO(2) of less than 3% of air saturation. Electron microscopic examination of cells revealed increased formation of membrane vesicles (MVs) on the surface of P. aeruginosa PAO1 under oxygen stress conditions. The toxicity of the supernatant of P. aeruginosa cultures to the growth of a hybridoma cell line significantly increased in samples taken from oxygen-stressed steady-state cultures. Furthermore, studies of adhesion in a continuous-flow biofilm culture revealed an increased adhesiveness for hydrophilic surfaces in P. aeruginosa PAO1 grown at a higher pO(2), The oxygen-dependent alterations of cell-surface components and properties observed in this work provide a possible explanation for the emergence of P. aeruginosa lacking the B-band LIPS in chronically infected cystic fibrosis patients. The results are also useful for understanding the processes involved in the formation of MVs in P. aeruginosa.