Induction of L-form-like cell shape change of Bacillus subtilis under microculture conditions
Induction of L-form-like cell shape change of Bacillus subtilis under microculture conditions
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DOI：
10.1099/mic.0.26259-0
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发表时间：
2003-09-01
期刊：
影响因子：
2.8
通讯作者：
Fukui, K
中科院分区：
文献类型：
--
作者：
Shingaki, R;Kasahara, Y;Fukui, K
在CI琼脂培养基（添加微量酵母提取物和酪蛋白氨基酸的Spizizen基本培养基）上的微量培养条件下，在枯草芽孢杆菌菌株168中观察到显著的细胞形状变化。在盖玻片下培养的细胞在形态上从杆状变为球形，大而不规则的形状，与L型细胞非常相似。仅在CI培养基中观察到细胞形状的变化，而在单独的Spizizen基本培养基或其他丰富培养基中未观察到细胞形状的变化。盖玻片下生长的细胞和CI琼脂平板上生长的细胞的全细胞蛋白质谱在几个方面不同。串联质谱分析的9个凝胶带，不同的蛋白质表达的两种条件之间表明，硝酸盐呼吸和发酵相关的蛋白质表达在盖玻片下生长的变形细胞。当培养基中加入过量的KNO 3时，CI培养物的细胞形状变化受到抑制。用0.1%KNO3生长的正常杆状细胞和不使用KNO 3生长的形状改变的细胞的全细胞蛋白分析揭示，在形状改变的细胞中支链α-酮酸脱氢酶复合物（由bfmB基因座编码）的表达升高。bfmB位点的失活导致细胞形状变化的抑制，并且其中bfmB表达由IPTG诱导的细胞确实显示形状变化。透射电子显微镜下观察到形态改变的细胞壁变薄，用0.1 M蔗糖溶液固定的细胞的质体变薄。阐明细胞壁变薄的机制可能会导致开发一种新型的细胞壁生物合成抑制剂。
A remarkable cell shape change was observed in Bacillus subtilis strain 168 under microculture conditions on CI agar medium (Spizizen's minimal medium supplemented with a trace amount of yeast extract and Casamino acids). Cells cultured under a cover glass changed in form from rod-shaped to spherical, large and irregular shapes that closely resembled L-form cells. The cell shape change was observed only with CI medium, not with Spizizen's minimum medium alone or other rich media. The whole-cell protein profile of cells grown under cover glass and cells grown on CI agar plates differed in several respects. Tandem mass analysis of nine gel bands which differed in protein expression between the two conditions showed that proteins related to nitrate respiration and fermentation were expressed in the shape-changed cells grown under cover glass. The cell shape change of CI cultures was repressed when excess KNO3 was added to the medium. Whole-cell protein analysis of the normal rod-shaped cells grown with 0.1 % KNO3 and the shape-changed cells grown without KNO3 revealed that the expression of the branched-chain a-keto acid dehydrogenase complex (coded by the bfmB gene locus) was elevated in the shape-changed cells. Inactivation of the bfmB locus resulted in the repression of cell shape change, and cells in which bfmB expression was induced by IPTG did show changes in shape. Transmission electron microscopy of ultrathin sections demonstrated that the shape-changed cells had thin walls, and plasmolysis of cells fixed with a solution including 0.1 M sucrose was observed. Clarifying the mechanism of thinning of the cell wall may lead to the development of a new type of cell wall biosynthetic inhibitor.