The cell envelope of gram-negative bacteria consists of two membranes, the inner and the outer membrane, that are separated by the periplasm. The outer membrane consists of phospholipids, lipopolysaccharides, integral membrane proteins, and lipoproteins. These components are synthesized in the cytoplasm or at the inner leaflet of the inner membrane and have to be transported across the inner membrane and through the periplasm to assemble eventually in the correct membrane. Recent studies in Neisseria meningitidis and Escherichia coli have led to the identification of several machineries implicated in these transport and assembly processes.

中文翻译：

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革兰氏阴性细菌外膜的生物发生。

革兰氏阴性细菌的细胞包膜由两层膜组成，内膜和外膜被周质分开。外膜由磷脂，脂多糖，整合膜蛋白和脂蛋白组成。这些成分在细胞质或内膜的内小叶中合成，必须转运穿过内膜并穿过周质，最终组装在正确的膜中。在脑膜炎奈瑟氏球菌和大肠杆菌中的最新研究已导致鉴定出与这些运输和组装过程有关的几种机械。