White S A, Claus G W
J Bacteriol. 1982 May;150(2):934-43. doi: 10.1128/jb.150.2.934-943.1982.
By using membrane-bound dehydrogenases, Gluconobacter oxydans characteristically accomplishes single-step oxidation of many polyols and quantitative release of the oxidation product into the medium. These cells typically differentiate by forming intracytoplasmic membranes (ICM) after exponential growth on glycerol. Earlier experiments demonstrated that glycerol-grown cells containing ICM oxidized glycerol more rapidly than cells which were harvested during exponential growth and lacked ICM (Claus et al., J. Bacteriol. 123:1169-1183). This report demonstrates that ICM are also formed after growth on sorbitol. Sorbitol-grown, ICM-containing maximum stationary-phase (MSP) cells showed from 50 to 300% greater oxidation (respiration) rates on mannitol, glycerol, glucose, meso-erythritol, and meso-inositol than did exponential-phase (EXP) cells which lacked ICM. Both EXP and MSP cells exhibited maximum sorbitol oxidation at pH 5.0, 38 degrees C, and 5% (wt/vol) sorbitol. When assayed under these optimum conditions, ICM-containing MSP cells demonstrated a 72% increase in respiration on sorbitol compared with that of EXP cells lacking ICM (oxygen quotients of 3,100 and 1,800, respectively). Gas chromatographic studies showed that sorbose was the only detectable product released from cells during oxygen quotient analysis. The specific activity of particulate-bound sorbitol dehydrogenase from ICM-containing MSP cells was twice that obtained from particulate fractions prepared from EXP cells lacking ICM. These results show that neither ICM formation after exponential growth nor increased respiration of other polyols is dependent upon the polyol used to grow cells. Our results suggest that increased respiratory activity of MSP cells is caused both by ICM formation and by increased synthesis (or activity) of the polyol dehydrogenases found in these membranes.
通过使用膜结合脱氢酶，氧化葡萄糖杆菌的特点是能对多种多元醇进行单步氧化，并将氧化产物定量释放到培养基中。这些细胞通常在甘油上指数生长后通过形成胞内膜（ICM）进行分化。早期实验表明，含有ICM的甘油生长细胞比指数生长期间收获且缺乏ICM的细胞氧化甘油的速度更快（克劳斯等人，《细菌学杂志》123:1169 - 1183）。本报告表明，在山梨醇上生长后也会形成ICM。与缺乏ICM的指数期（EXP）细胞相比，含有ICM的山梨醇生长的最大稳定期（MSP）细胞在甘露醇、甘油、葡萄糖、内消旋赤藓醇和内消旋肌醇上的氧化（呼吸）速率高50%至300%。EXP细胞和MSP细胞在pH 5.0、38℃和5%（重量/体积）山梨醇条件下均表现出山梨醇氧化最大值。在这些最佳条件下进行测定时，与缺乏ICM的EXP细胞相比，含有ICM的MSP细胞在山梨醇上的呼吸作用增加了72%（氧商分别为3100和1800）。气相色谱研究表明，在氧商分析期间，山梨糖是细胞释放的唯一可检测产物。来自含有ICM的MSP细胞的颗粒结合山梨醇脱氢酶的比活性是从缺乏ICM的EXP细胞制备的颗粒级分中获得的比活性的两倍。这些结果表明，指数生长后ICM的形成以及其他多元醇呼吸作用的增加均不依赖于用于培养细胞的多元醇。我们的结果表明，MSP细胞呼吸活性的增加是由ICM的形成以及这些膜中发现的多元醇脱氢酶合成（或活性）增加共同引起的。
