Hegermann J, Lünsdorf H, Overbeck J, Schrempf H
FB Biologie/Chemie, Angewandte Genetik der Mikroorganismen, Universität Osnabrück, Barbarastr 13, 49069, Osnabrück, Germany.
J Microsc. 2008 Jan;229(Pt 1):174-82. doi: 10.1111/j.1365-2818.2007.01863.x.
The distribution of polyphosphate (polyP) within the cytoplasmic membrane of Streptomyces lividans hyphae or protoplasts has been determined at high spatial resolution by elemental mapping using energy-filtered electron microscopy (EFTEM). The results revealed that polyP was best traceable after its interaction with lead ions followed by their precipitation as lead sulphide. Concomitant studies of the S.lividans wildtype (WT) strain and its co-embedded mutant DeltaK (lacking a functional kcsA gene) were conducted by labelling as the surface matrix of either one was labelled by cationic colloidal thorium dioxide. Within the WT strain, additional polyP was found to accumulate distinctly at the inner face of the cytoplasmic membrane. After removal of the cell wall (within protoplasts), the polyP-derived lead-sulphide (PbS) precipitate formed clusters of fibrillar material extending up to 50 nm into the cytoplasm. This feature was absent in the DeltaK mutant strain. Together the results revealed that the presence of the KcsA channel and the structured polyP coincide.
利用能量过滤电子显微镜（EFTEM）通过元素映射在高空间分辨率下测定了淡紫链霉菌菌丝或原生质体细胞质膜内多聚磷酸盐（polyP）的分布。结果表明，多聚磷酸盐与铅离子相互作用后，随后以硫化铅形式沉淀，此时最易于追踪。通过用阳离子胶体二氧化钍标记对淡紫链霉菌野生型（WT）菌株及其共包埋突变体DeltaK（缺乏功能性kcsA基因）进行了同步研究，因为其中任何一种的表面基质都用阳离子胶体二氧化钍标记。在WT菌株中，发现额外的多聚磷酸盐明显积聚在细胞质膜的内表面。去除细胞壁后（原生质体内），多聚磷酸盐衍生的硫化铅（PbS）沉淀形成了延伸至细胞质内达50 nm的纤维状物质簇。DeltaK突变菌株中不存在此特征。这些结果共同表明，KcsA通道的存在与结构化多聚磷酸盐是一致的。
