Hendry A T, Dillon J R
Can J Microbiol. 1984 Nov;30(11):1319-25. doi: 10.1139/m84-212.
Growth inhibition by phenylalanine (0.25 mmol/L in defined agar media) was present in about 1% of over 1000 clinical isolates of Neisseria gonorrhoeae isolates tested. Turbidometry of several phenylalanine-sensitive isolates showed that their growth rates decreased in proportion to phenylalanine concentrations up to about 1 mmol/L. The growth rate was unaffected if 0.04 mmol/L tyrosine was also present. The phenylalanine analogue DL-3-fluorophenylalanine inhibited the growth of all 23 isolates further tested on agar. This inhibition was depressed by phenylalanine in all 17 phenylalanine-resistant isolates. Phenylalanine plus tyrosine were required to derepress the analogue inhibition in the other six phenylalanine-sensitive isolates. Phenylalanine-sensitive isolates may have a defect in aromatic amino acid synthesis, not involving auxotrophy, but manifested through regulation of the pathways. Phenylalanine effectively repressed tyrosine and phenylalanine synthesis. In 125 isolates including 85 beta-lactamase producers (PPNG) and 32 phenylalanine-sensitive isolates, phenylalanine inhibited 63.2% of 38 PPNG isolates carrying the 3.2 megadalton (Md) plasmid, but only one of 47 PPNG isolates carrying the 4.5 Md plasmid. PPNG isolates are most often of the proline, ornithine, or nonrequiring auxotypes. Phenylalanine sensitivity did not appear to be auxotype dependent.
在检测的1000多株淋病奈瑟菌临床分离株中，约1%的菌株在限定琼脂培养基中（苯丙氨酸浓度为0.25 mmol/L）出现生长抑制。对几株对苯丙氨酸敏感的分离株进行比浊法检测发现，在苯丙氨酸浓度高达约1 mmol/L时，其生长速率随苯丙氨酸浓度成比例下降。如果同时存在0.04 mmol/L酪氨酸，则生长速率不受影响。苯丙氨酸类似物DL-3-氟苯丙氨酸抑制了在琼脂上进一步检测的所有23株分离株的生长。在所有17株对苯丙氨酸耐药的分离株中，苯丙氨酸可抑制这种抑制作用。在其他6株对苯丙氨酸敏感的分离株中，需要苯丙氨酸加酪氨酸来解除类似物的抑制作用。对苯丙氨酸敏感的分离株可能在芳香族氨基酸合成方面存在缺陷，这与营养缺陷无关，而是通过途径调节表现出来。苯丙氨酸有效地抑制了酪氨酸和苯丙氨酸的合成。在125株分离株中，包括85株β-内酰胺酶产生菌（PPNG）和32株对苯丙氨酸敏感的分离株，苯丙氨酸抑制了携带3.2兆道尔顿（Md）质粒的38株PPNG分离株中的63.2%，但仅抑制了携带4.5 Md质粒的47株PPNG分离株中的1株。PPNG分离株最常见的是脯氨酸、鸟氨酸或非营养缺陷型。苯丙氨酸敏感性似乎与营养缺陷型无关。
