Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093.
Appl Environ Microbiol. 1987 Mar;53(3):527-32. doi: 10.1128/aem.53.3.527-532.1987.
Many deep-sea bacteria are specifically adapted to flourish under the high hydrostatic pressures which exist in their natural environment. For better understanding of the physiology and biochemistry of these microorganisms, properties of the glucose transport systems in two barophilic isolates (PE-36, CNPT-3) and one psychrophilic marine bacterium (Vibrio marinus MP1) were studied. These bacteria use a phosphoenol-pyruvate:sugar phosphotransferase system (PTS) for glucose transport, similar to that found in many members of the Vibrionaceae and Enterobacteriaceae. The system was highly specific for glucose and its nonmetabolizable analog, methyl alpha-glucoside (a-MG), and exhibited little affinity for other sugars tested. The temperature optimum for glucose phosphorylation in vitro was approximately 20 degrees C. Membrane-bound PTS components of deep-sea bacteria were capable of enzymatically cross-reacting with the soluble PTS enzymes of Salmonella typhimurium, indicating functional similarities between the PTS systems of these organisms. In CNPT-3 and V. marinus, increased pressure had an inhibitory effect on a-MG uptake, to the greatest extent in V. marinus. Relative to atmospheric pressure, increased pressure stimulated sugar uptake in the barophilic isolate PE-36 considerably. Increased hydrostatic pressure inhibited in vitro phosphoenolpyruvate-dependent a-MG phosphorylation catalyzed by crude extracts of V. marinus and PE-36 but enhanced this activity in crude extracts of the barophile CNPT-3. Both of the pressure-adapted barophilic bacteria were capable of a-MG uptake at higher pressures than was the nonbarophilic psychrophile, V. marinus.
许多深海细菌专门适应在其自然环境中存在的高压下繁荣。为了更好地理解这些微生物的生理学和生物化学特性，研究了两种耐压分离株（PE-36、CNPT-3）和一种嗜冷海洋细菌（Vibrio marinus MP1）的葡萄糖转运系统的特性。这些细菌使用磷酸烯醇丙酮酸：糖磷酸转移酶系统（PTS）进行葡萄糖转运，类似于许多弧菌科和肠杆菌科成员中发现的 PTS。该系统对葡萄糖及其非代谢类似物甲基α-葡萄糖苷（a-MG）具有高度特异性，并且对测试的其他糖几乎没有亲和力。体外葡萄糖磷酸化的最适温度约为 20 摄氏度。深海细菌的膜结合 PTS 成分能够与鼠伤寒沙门氏菌的可溶性 PTS 酶发生酶促交叉反应，表明这些生物体的 PTS 系统之间存在功能相似性。在 CNPT-3 和 V. marinus 中，压力增加对 a-MG 摄取有抑制作用，在 V. marinus 中最为明显。与大气压相比，耐压分离株 PE-36 中的压力增加大大刺激了糖的摄取。增加的静水压力抑制了 V. marinus 和 PE-36 粗提物中磷酸烯醇丙酮酸依赖的 a-MG 磷酸化的体外催化，但增强了耐压分离株 CNPT-3 中该活性。两种适应压力的耐压细菌都能够在比非耐压嗜冷菌 V. marinus 更高的压力下摄取 a-MG。
