Ribosomal RNA content in microcolony forming soil bacteria measured by quantitative 16S rRNA hybridization and image analysis
Ribosomal RNA content in microcolony forming soil bacteria measured by quantitative 16S rRNA hybridization and image analysis
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DOI：
10.1111/j.1574-6941.2001.tb00870.x
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发表时间：
2001-11-01
影响因子：
4.2
通讯作者：
Hansen, M
中科院分区：
文献类型：
--
作者：
Binnerup, SJ;Bloem, J;Hansen, M
研究了产碱杆菌A2的生长速率、rRNA浓度和rRNA操纵子数量之间的相关性。荧光假单胞菌R2 f和芽孢杆菌B1细胞在1/10浓度胰蛋白酶大豆肉汤（1/10 TSB）液体培养基中呈指数生长，并在漂浮在1/10 TSB上的聚碳酸酯膜滤器上生长至微菌落（mCFU）大小。rRNA的浓度也确定在细胞中形成的mCFU的根际和散装土壤样品从大麦（大麦）微观实验的膜上孵育后。采用直接在聚碳酸酯滤膜上进行荧光原位杂交的方法，结合激光共聚焦扫描显微镜和图像分析，测量了mCFU内单个细胞的探针强度。我们发现，在膜上形成mCFU的细胞的rRNA浓度略高于在液体培养基中生长的细胞。产碱杆菌属A2、荧光假单胞菌R2 f和芽孢杆菌属B1的生长速率和rRNA浓度的平均值分别为0.31、0.61和0.63 h（-1），以及52、63和146单位/细胞面积。当生长在膜上时。这三种细菌携带的rrna操纵子的数量被确定为2到3个，4个和7到9个。产碱菌A2只携带2 ~ 3个rRNA操纵子，其rRNA含量最低。此外，与荧光假单胞菌R2 f和芽孢杆菌B1相比，该微生物的生长速率较低。虽然荧光假单胞菌R2 f和芽孢杆菌B1具有相同的生长速率，但芽孢杆菌B1表达的rRNA浓度要高得多。这很好地反映了该细菌携带的大量rRNA操纵子。在两种环境中，根际和散装土壤样品孵育后获得的mCFU的平均探测强度变化超过4倍。表达低浓度rRNA的mCFU形成细菌的百分比在根际中至少与在散装土壤中一样高。背后携带高拷贝数的rRNA操纵子和保持高浓度的rRNA在生长过程中的基本原理进行了讨论。(C)2001年，欧洲微生物学会联合会。由Elsevier Science B. V.出版，版权所有。
The correlation between the growth rate, rRNA concentration and number of rrna operons was studied in Alcaligenes sp. A2. Pseudomonas fluorescens R2f and Bacillus sp. B1 cells grown exponentially in liquid 1/10 strength tryptic soy broth (1/10 TSB) medium and grown to microcolony (mCFU) size on polycarbonate membrane filters floating on 1/10 TSB. The rRNA concentration was also determined in cells forming mCFUs after incubation on membranes of rhizosphere and bulk soil samples taken from a barley (Hordeum vulgare) microcosm experiment. A protocol for fluorescent in situ hybridization directly on polycarbonate membrane filters combined with confocal laser scanning microscopy and image analysis was used to measure the probing intensity from individual cells within the mCFUs, We found that cells forming mCFU on membranes had a rRNA concentration slightly higher than cells grown in fluid medium. Mean values of growth rates and rRNA concentration measured as a probing intensity per cell area were 0.31, 0.61 and 0.63 h(-1) and 52, 63 and 146 units per cell area for Alcaligenes sp. A2, P. fluorescens R2f, and Bacillus sp. B1, respectively. when grown on membranes. The number of rrna operons carried by the three bacteria was determined to be between two to three, four and seven to nine. Alcaligenes sp, A2 which carried only two to three rrna operons had the lowest concentration of rRNA. Furthermore this organism had a lower growth rate compared to P. fluorescens R2f, and Bacillus sp. B1. Although P. fluorescens R2f and Bacillus sp. B1 had the same growth rate, Bacillus sp. B1 expressed a much higher rRNA concentration. which reflected well the high number of rrna operons carried by this bacterium. The mean probing intensity of mCFUs obtained after incubation of rhizosphere and bulk soil samples varied more than four-fold in both environments. The percentage of mCFU forming bacteria expressing a low concentration of rRNA was at least as high in the rhizosphere as in the bulk soil. The rationale behind carrying a high copy number of rrna operons and maintaining high concentrations of rRNA during growth is discussed. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.