Grant W D, Sutherland I W, Wilkimson J F
J Bacteriol. 1970 Jul;103(1):89-96. doi: 10.1128/jb.103.1.89-96.1970.
The nucleotide pools of certain mucoid, colanic acid-synthesizing strains of Escherichia coli, Salmonella typhimurium, and Aerobacter cloacae were examined, and in all cases the nucleotide sugars uridine-5'-diphosphate glucose (UDPG), uridine-5'-diphosphate galactose (UDPGal), guanosine-5'-diphosphate fucose (GDPF), and uridine-5'-diphosphate glucuronic acid (UDPGA) were detected. It is postulated that these nucleotide sugars are precursors in the synthesis of colanic acid. The levels of these nucleotide sugars and of the enzymes involved in their synthesis were examined in a number of mucoid strains and compared with the levels found in certain strains which were repressed in the synthesis of colanic acid, only becoming mucoid when grown in the presence of p-fluorophenylalanine (PFA). The levels of UDPG and UDPGal and the enzymes involved in their synthesis were substantially the same in both mucoid and repressed types, but the levels of UDPGA and GDPF and of some of the enzymes involved in their synthesis were much higher in mucoid strains. When repressed strains were grown in the presence of PFA, the levels of UDPGA and GDPF approached those found in mucoid strains. The existence of an operon, containing genes coding for certain key enzymes involved in colanic acid synthesis has been suggested.
对某些能合成类粘蛋白、柯氏酸的大肠杆菌、鼠伤寒沙门氏菌和阴沟肠杆菌菌株的核苷酸库进行了检测，在所有情况下均检测到了核苷酸糖，即尿苷 - 5'-二磷酸葡萄糖（UDPG）、尿苷 - 5'-二磷酸半乳糖（UDPGal）、鸟苷 - 5'-二磷酸岩藻糖（GDPF）和尿苷 - 5'-二磷酸葡糖醛酸（UDPGA）。据推测，这些核苷酸糖是柯氏酸合成的前体。在一些类粘蛋白菌株中检测了这些核苷酸糖及其合成相关酶的水平，并与某些在柯氏酸合成中受到抑制、仅在对氟苯丙氨酸（PFA）存在下生长时才变为类粘蛋白的菌株中的水平进行了比较。类粘蛋白型和受抑制型菌株中UDPG和UDPGal及其合成相关酶的水平基本相同，但类粘蛋白菌株中UDPGA和GDPF及其合成相关的一些酶的水平要高得多。当受抑制菌株在PFA存在下生长时，UDPGA和GDPF的水平接近类粘蛋白菌株中的水平。有人提出存在一个操纵子，其中包含编码柯氏酸合成中某些关键酶的基因。
