STRUCTURE FUNCTION SYNTHESIS AND GENETIC CONTROL OF BACTERIAL PILI AND A MOLECULAR MODEL FOR DNA AND RNA TRANSPORT IN GRAM NEGATIVE BACTERIA
STRUCTURE FUNCTION SYNTHESIS AND GENETIC CONTROL OF BACTERIAL PILI AND A MOLECULAR MODEL FOR DNA AND RNA TRANSPORT IN GRAM NEGATIVE BACTERIA
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DOI：
10.1111/j.2164-0947.1965.tb02342.x
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发表时间：
1965-01-01
期刊：
影响因子：
--
通讯作者：
BRINTON, CC
中科院分区：
文献类型：
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作者：
BRINTON, CC
细菌菌毛被定义为除鞭毛之外的任何形态上不同的细菌细胞丝状附属物。 pili 这个词源自拉丁语，意思是头发或头发状结构。它们广泛存在于革兰氏阴性细菌中，特别是从天然来源新鲜分离的菌株中。由于在通常的实验室条件下，显微镜下可见的菌毛对于生长或生存不是必需的，因此，菌毛细菌代表了在特殊条件下具有特殊功能的细胞的分化形式。本文介绍的工作是 1951 年至 1965 年间在匹兹堡大学和日内瓦大学生物物理系、剑桥分子生物学研究所、沃尔特·里德陆军研究所和匹兹堡大学医学院微生物学系进行的菌毛研究的简要总结。 1-11从形态上来说，菌毛太薄而无法通过普通光学显微镜看到，必须通过电子显微镜观察。尽管尚未对新菌毛种类进行详尽而系统的搜索，但已发现六种不同的形态类型，并按发现顺序编号或根据功能命名（表 1）。尽管对于给定类型来说，菌毛的直径相当恒定，但即使在同一细胞上的菌毛之间，它们的长度也是可变的。与鞭毛不同，它们是直的，有的看起来是刚性的。菌毛通常均匀分布在细胞的整个表面。图1显示了大肠杆菌K12 F-上存在的I型菌毛，图2显示了变形杆菌上的IV型菌毛和鞭毛；图3显示变形杆菌上的111型菌毛、IV型菌毛和鞭毛；图4显示了大肠杆菌K12 HfrC上的I型、V型和F菌毛。 F 菌毛覆盖有 RNA 雄性噬菌体 M12，F 菌毛是其受体。 IV 型菌毛具有螺旋表面精细结构，其螺距足够长，可以在显微照片中看到。仅对 I 型菌毛和 F 型菌毛进行了详细研究。 I型菌毛可以通过多种技术分离、浓缩和纯化。 5 最方便的方法是在高速混合器中机械搅拌两分钟将其从细胞中去除，并通过低速离心将其与脱毛细胞分离。在PH 3.92下进行等电沉淀，使上清液中的菌毛与一些杂质一起聚集，并且可以通过低速离心将它们浓缩。然后在冷条件下用 MgCl2 将重悬并中和的制剂制成 0.1 M。这特别聚集了 I 型菌毛，并出现强烈的流式双折射。通过低速离心除去结晶菌毛聚集体并重悬于蒸馏水中。再进行两次镁沉淀循环，产生菌毛悬浮液，根据紫外光谱、电子显微镜、化学分析、结晶度、
Bacterial pili are defined as any morphologically distinct filamentous appendage of bacterial cells other than flagella. The word pili is derived from the Latin word meaning hair or hair-like structure. They occur very widely among gram-negative bacteria, particularly on strains freshly isolated from natural sources. Since microscopically visible pili are not necessary for growth or viability under the usual laboratory conditions, piliated bacteria represent a differentiated form of the cell having special functions under special conditions. The work presented here is a brief summary of research on pili carried out between 1951 and 1965 at the Biophysics Departments of the University of Pittsburgh and the University of Geneva, the Institute for Molecular Biology at Cambridge, Walter Reed Army Institute of Research, and the Department of Microbiology of the University of Pittsburgh Medical School. 1-11Morphologically, pili are too thin to be visible by ordinary light microscopy and must be visualized by electron microscopy. Although an exhaustive and systematic search for new kinds of pili has not been made, six distinct morphological types have been found and numbered in order of discovery or named according to function (TABLE 1). Although the diameter of pili is quite constant for a given type, their length is variable even among pili on the same cell. Unlike flagella, they are straight, and some appear to be rigid. Pili are usually distributed evenly over the entire surface of the cell. FIGURE 1 shows Type I pili present on E. coli K12 F-, FIGURE 2 shows Type IV pili and flagella on Proteus; FIGURE 3 shows Type 111 pili, Type IV pili and flagella on Proteus; and FIGURE 4 shows Type I, Type V and F pili on E. coli K12 HfrC. The F pili are coveredwiththe RNA male phage M12 for which they are the receptor. The Type IV pili have a helical surface fine structure of sufficiently long pitch distance to be visible in the micrograph. Only Type I pili and F pili have been studied in detail. Type I pili may be isolated, concentrated and purified by several techniques. 5 The most convenient is to remove them from the cells by two minutes of mechanical agitation in a high speed mixer and separate them from the depiliated cells by low speed centrifugation. An isoelectric precipitation at PH 3.92 serves to aggregate the pili in the supernatant liquid along with some of the impurities, and they may be concentrated by low speed centrifugation. The resuspended and neutralized preparation is then made 0.1 M with MgC12 in the cold. This specifically aggregates Type I pili, and strong streaming birefringence appears. The crystalline pili aggregates are removed by low speed centrifugation and resuspended in distilled water. Two more cycles of magnesium precipitation yield a pili suspension which is pure by the criteria of UV spectroscopy, electron microscopy, chemical analysis, crystallinity,