Alban P Scott, Johnson Paul W, Nelson David R
Department of Biochemistry, Microbiology, and Molecular Genetics1, and Electron Microscope Facility2, University of Rhode Island, Kingston, RI 02881, USA.
Microbiology (Reading). 2000 Jan;146 ( Pt 1):119-127. doi: 10.1099/00221287-146-1-119.
It has been demonstrated previously that motile Borrelia burgdorferi cells transform into non-motile cyst-forms when incubated for several weeks in BSKII (a complex medium) lacking rabbit serum. B. burgdorferi cells cannot synthesize fatty acids de novo and serum is thought to provide a source of fatty acids and lipids. When B. burgdorferi cells were serum-starved in defined RPMI medium, -90% of the cells formed spherical cysts within 48 h. Cyst formation was inhibited by tetracycline. Cyst opening and recovery of vegetative cells was rapidly induced by the addition of either BSKII or rabbit serum. The percentage of viable cells recovered from cysts ranged from 2.9% to 52-5%. Viability was inversely proportional to cyst age. Protein synthesis by B. burgdorferi during serum starvation was examined by labelling cells with Tran35S-Label and analysing the labelled proteins by two-dimensional gel electrophoresis and fluorography. The synthesis of over 20 proteins was induced during serum starvation. Western blots of proteins from vegetative cells and cysts probed with sera from either B. burgdorferi-infected humans or monkeys revealed that several cyst proteins were antigenic. These data suggest that cells of B. burgdorferi, although possessing a small genome and extremely limited biosynthetic capabilities, rapidly respond to conditions of serum starvation by inducing changes in protein synthesis and cell morphology. This study may help explain how cells of B. burgdorferi can survive periods of nutrient deprivation in different hosts and host tissues.
先前已经证明，运动性的伯氏疏螺旋体细胞在缺乏兔血清的BSKII（一种复合培养基）中孵育数周后会转变为不运动的囊肿形式。伯氏疏螺旋体细胞不能从头合成脂肪酸，血清被认为是脂肪酸和脂质的来源。当伯氏疏螺旋体细胞在限定的RPMI培养基中血清饥饿时，-90%的细胞在48小时内形成球形囊肿。囊肿形成受到四环素的抑制。通过添加BSKII或兔血清可迅速诱导囊肿开放和营养细胞的恢复。从囊肿中回收的活细胞百分比在2.9%至52-5%之间。活力与囊肿年龄成反比。通过用Tran35S-Label标记细胞并用二维凝胶电泳和荧光自显影分析标记蛋白，研究了血清饥饿期间伯氏疏螺旋体的蛋白质合成。血清饥饿期间诱导了20多种蛋白质的合成。用来自感染伯氏疏螺旋体的人类或猴子的血清对营养细胞和囊肿的蛋白质进行免疫印迹分析，结果显示几种囊肿蛋白具有抗原性。这些数据表明，伯氏疏螺旋体细胞虽然基因组小且生物合成能力极其有限，但通过诱导蛋白质合成和细胞形态的变化对血清饥饿条件迅速做出反应。这项研究可能有助于解释伯氏疏螺旋体细胞如何在不同宿主和宿主组织的营养剥夺期存活下来。
