%0 Journal Article
%T Incorporation of phosphatidylcholine into Escherichia coli membrane affects secretion of penicillin b-lactamase<br>掺入大肠杆菌膜中的磷脂酰胆碱(PC)影响青霉素b-内酰胺酶的分泌
%A Xueli Cai
%A Yang Li
%A Wenjing Xuan
%A Xinguo Wang
%A <br>蔡雪丽
%A 李洋
%A 宣文静
%A 王行国
%J 微生物学报
%D 2008
%I 
%X OBJECTIVE: To study the biological function of phosphatidylcholine in bacteria, the borrelial pcs gene was inserted into ptac85 plasmid. Then E. coli Top10 pcs+ was constructed via the transformation of the recombinant plasmid. Phosphatidylcholine (30%) in total phospholipids was achieved when the bacterial cells were incubated in Luria-Bertani (LB) medium supplemented with 1% choline and induced by 0.5 mmol/L isopropy-beta-D-thiogalactoside (IPTG) for 4-8 hours at 37 degrees C. METHODS: Ampicillin inhibitionof E. coli Top10 pcs+ was tested at first, and then beta-lactamase activity in periplasm was examined. Finally Western blot was used to detect the amount of beta-lactamase in both bacterial periplasm and cytoplasm. RESULTS: Antibiotic tests showed that high concentrations of ampicillin inhibited the growth of E. coli Top100 pcs+ with an IC50 of 70-800 microg/mL. Active assays revealed that the beta-lactamase activity in periplasm was only 1/5 of that for the control strain E. coli Top10/p(tac)85. Western blotting confirmed that the low activity of beta-lactamase in E. coli Top10 pcs+ resulted from a lower amount of beta-lactamase in its periplasm. CONCLUSION: Our results demonstrated that the phospatidylcholine incorporated into bacterial membrane retarded secretion of Escherichia coli penicillin beta-lactamase from cytoplasm into periplasm, which suggested that phosphatidylcholine might play a role in the regulation of protein secretion in those bacteria able to synthesize phosphatidylcholine.
%K Phosphatidylcholine
%K b-lactamase
%K protein secretion
%K Ampicillin<br>磷脂酰胆碱
%K β-内酰胺酶
%K 氨苄青霉素
%K 蛋白分泌
%K 掺入
%K 大肠
%K 菌膜
%K 磷脂酰胆碱
%K 影响
%K 氨苄青霉素
%K 内酰胺酶
%K penicillin
%K secretion
%K membrane
%K Escherichia
%K coli
%K phosphatidylcholine
%K Incorporation
%K 作用
%K 蛋白转运
%K 调节
%K 空间
%K 转运途径
%K 双分子层
%K 抗性
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=A3C6BA55AB623B90FA9104CFFC826F3C&aid=B74BF849F85B41AE37E48FB342505D7E&yid=67289AFF6305E306&vid=B6DA1AC076E37400&iid=E158A972A605785F&sid=8C8D895E58E44DBB&eid=ABF2590617D31FFD&journal_id=0001-6209&journal_name=微生物学报&referenced_num=0&reference_num=21