Lipid composition and the synthesis system that responds to environmental change in Stapylococcus aureus.

金黄色葡萄球菌的脂类组成和合成系统随环境压力而变化。心磷脂(CL)是细菌的主要磷脂成分，在响应高渗透压过程中起着重要作用。心磷脂的相对含量从10%(在含0.85%NaC_1的介质中)增加到50%(在含10%的NaC_1介质中)，而磷脂酰甘油(PG)从占总磷脂的65%降至40%。赖氨酸磷脂酰甘油含量保持不变。心磷脂合成基因(CLS)被认为在响应高渗透压中起关键作用。克隆了CLS基因，并在金黄色葡萄球菌中高效表达。它没有产生较高的CL含量。金黄色葡萄球菌上的缺陷菌株即使经过多次试验也无法分离出来。在大肠杆菌中，成功地分离到了缺失或破坏的cls基因，据报道该菌株在细胞分裂过程中表现出一定的紊乱。CLS在金黄色葡萄球菌中似乎是必不可少的，但进一步的试验应该继续进行。在金黄色葡萄球菌的三个西格玛因子中，西格玛B(σ^a B)被认为与CLS的表达有关。σ^B在金黄色葡萄球菌中的过表达增加了CL的含量，但该基因的缺陷并不影响CL的合成。σ^B在CL合成中的调控作用有待进一步研究。既然赖氨酰磷脂酰甘油基因的破坏可以促进CL的合成，那么膜脂组成和功能的调控机制就需要基于基因组网络信息进行更全面的研究。在报告中，从分子结构、功能和形态发生方面简要讨论了对细菌细胞膜的更全面的洞察。

The lipids composition and the synthesis system in Staphylococcus aureus are changeable depending upon environmental stresses. Cardiolipin(CL), a major phospholipids component of the bacteria, has been suggested to play important role in responding to high osmotic pressure. The relative content of cardiolipin increased from 10% ( in 0.85% NaC1 containing medium) to 50%( in 10% NaC1 containing medium), while phsphatidylglycerol(PG) decreased from 65% to 40% of the total phospholipids. Lysylphosphatidylglycerol content remained constant. Cardiolipin synthesis genes(cls) was suspected to play key role in responding to high osmotic pressure. The cls was cloned and expressed in over expression system in S. aureus. It did not produce higher content of CL. The defective strain on S. aureus could not be isolated even after many trials. In E. coli, the defective or destructed cls gene was successfully isolated and it was reported that the strain showed some disorders in cell division process. The cls appears to be essential in S. aueus but further trial should be continued. Among the three sigma factors of S. aureus, sigma B (σ^a B) was suggested to be correlated with the cls expression. The over expression ofσ^B in S. aureus enhanced CL content but the defect of the gene did not affect CL synthesis. The regulatory role of σ^B in CL synthesis needs to further study. Since the destruction of lysylphosphatidylglycerol gene was reported to enhance CL synthesis, the regulatory mechanism of membrane lipid composition and the function should be more globally studied basing on the genome-net work information. In the report, more global insight into bacterial cell membrane was briefly discussed in terms of the molecular structure, function and morphogenesis.