The outer membrane of a heterocyst‐forming cyanobacterium is a permeability barrier for uptake of metabolites that are exchanged between cells
The outer membrane of a heterocyst‐forming cyanobacterium is a permeability barrier for uptake of metabolites that are exchanged between cells
复制标题
形成异形胞的蓝细菌的外膜是吸收细胞间交换的代谢物的渗透性屏障
作者：
Kerstin Nicolaisen;Vicente Mariscal;R. Bredemeier;R. Pernil;S. Moslavac;R. López;I. Maldener;A. Herrero;E. Schleiff;E. Flores
多细胞鱼腥藻 sp。 PCC 7120 菌株是一种丝状蓝细菌，可以将 N2 固定在称为异形细胞的分化细胞中，异形细胞与邻近的光合营养细胞交换营养和调节化合物。该细菌的外膜沿着细丝连续，限定连续的周质空间。鱼腥藻 alr0075、alr2269 和 alr4893 基因产物被定性为 Omp85 样蛋白，通常参与外膜蛋白的生物发生。开放阅读框alr2269是操纵子的第一个基因，该操纵子还携带脂多糖脂质A生物合成的基因，包括alr2270（lpxC同源物）。携带失活alr2269或alr2270构建体的菌株显示出对红霉素、SDS、溶菌酶和蛋白酶K的敏感性增强，表明它们产生具有增加的渗透性的外膜。这些菌株进一步表现出对蔗糖、谷氨酸的摄取增加，以及在较小程度上对一些其他氨基酸的摄取增加。通过对野生型鱼腥藻丝进行机械断裂，可以增加对相同代谢物的吸收。这些结果证明，外膜是蔗糖和谷氨酸等代谢物的渗透性屏障，这些代谢物在形成异形囊的蓝细菌的固氮丝中进行细胞间交换。
The multicellular Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can fix N2 in differentiated cells called heterocysts, which exchange nutritional and regulatory compounds with the neighbour photosynthetic vegetative cells. The outer membrane of this bacterium is continuous along the filament defining a continuous periplasmic space. The Anabaena alr0075, alr2269 and alr4893 gene products were characterized as Omp85‐like proteins, which are generally involved in outer membrane protein biogenesis. Open reading frame alr2269 is the first gene of an operon that also carries genes for lipopolysaccharide lipid A biosynthesis including alr2270 (an lpxC homologue). Strains carrying inactivating alr2269 or alr2270 constructs showed enhanced sensitivity to erythromycin, SDS, lysozyme and proteinase K suggesting that they produce an outer membrane with increased permeability. These strains further exhibited increased uptake of sucrose, glutamate and, to a lesser extent, a few other amino acids. Increased uptake of the same metabolites was obtained by mechanical fragmentation of wild‐type Anabaena filaments. These results document that the outer membrane is a permeability barrier for metabolites such as sucrose and glutamate, which are subjected to intercellular exchange in the diazotrophic filament of heterocyst‐forming cyanobacteria.
影响因子：
3.5
作者：
Cormack, BP;Valdivia, RH;Falkow, S
通讯作者：
Falkow, S
DOI：
10.1073/pnas.0604744103
发表时间：
2006-08-01
影响因子：
11.1
作者：
Wu, Tao;McCandlish, Andrew C.;Kahne, Daniel
通讯作者：
Kahne, Daniel