Keevil C W, Davies D B, Spillane B J, Mahenthiralingam E
Pathogenic Microbes Research Laboratory, PHLS Centre for Applied Microbiology and Research, Salisbury, Wilts., UK.
J Gen Microbiol. 1989 Apr;135(4):851-63. doi: 10.1099/00221287-135-4-851.
Neisseria gonorrhoeae strains P9-2 (PenS) and KW2 (PenR) were grown in chemostats of nonferrous design at constant growth rate, pH and dissolved oxygen tension. Iron limitation (micromax 0.1 h-1) was imposed by omitting iron salts from the defined medium and titrating increasing concentrations of the non-metabolizable iron chelators ovotransferrin and Desferal, to progressively decrease the growth yield. Metabolic activity during iron limitation was very high, with a qGlc which was 2- or 11-fold greater than during cystine- or glucose-limited growth, respectively. More aspartate and isoleucine were metabolized during cystine-limited growth, while more glutamate, proline and serine were metabolized during glucose- or iron-limited growth. Significant concentrations of alanine or valine were excreted during cystine- or glucose-limited growth, respectively. Iron-limited growth of an initial inoculum of non-piliated, transparent colony-forming (P-O-) gonococci resulted in the selection of 100% piliated bacteria. Initial inocula of P+O- gonococci retained this phenotype for over 100 generations. Iron-limited gonococci were extremely virulent in the guinea-pig subcutaneous chamber model and inocula of even 12 bacteria grew rapidly and persisted. By contrast, cystine-limited (iron-replete) gonococci retained piliation but did not survive in the chambers. Transition from iron-limited to glucose-limited growth resulted in marked loss of piliation but the bacteria remained virulent. Loss of virulence did not correlate with susceptibility to killing by normal human serum, nor with changes in the content or composition of lipooligosaccharide, which contained 2.9, 3.7, 4.3 and 4.8 kDa moieties. Additional proteins were detectable in Sarkosyl-purified outer membranes of iron-limited gonococci but several proteins with molecular masses similar to those described in the literature for iron-restricted gonococci were detectable in cystine- or glucose-limited bacteria.
淋病奈瑟菌菌株P9 - 2（青霉素敏感型）和KW2（青霉素耐药型）在非铁制恒化器中以恒定的生长速率、pH值和溶解氧张力进行培养。通过在限定培养基中省略铁盐并滴定增加浓度的不可代谢铁螯合剂卵转铁蛋白和去铁胺，施加铁限制（最大生长速率0.1 h⁻¹），以逐步降低生长产量。铁限制期间的代谢活性非常高，其葡萄糖代谢率（qGlc）分别比胱氨酸限制或葡萄糖限制生长期间高2倍或11倍。在胱氨酸限制生长期间，更多的天冬氨酸和异亮氨酸被代谢，而在葡萄糖或铁限制生长期间，更多的谷氨酸、脯氨酸和丝氨酸被代谢。在胱氨酸或葡萄糖限制生长期间，分别排出了显著浓度的丙氨酸或缬氨酸。未形成菌毛、透明菌落形成（P - O⁻）的淋球菌初始接种物在铁限制条件下生长，导致100%形成菌毛的细菌被筛选出来。P⁺O⁻淋球菌的初始接种物在超过100代中保持了这种表型。铁限制的淋球菌在豚鼠皮下腔室模型中极具毒性，即使接种12个细菌也能快速生长并持续存在。相比之下，胱氨酸限制（铁充足）的淋球菌保留了菌毛，但在腔室中无法存活。从铁限制生长转变为葡萄糖限制生长导致菌毛显著丧失，但细菌仍具有毒性。毒力丧失与对正常人血清杀伤的敏感性无关，也与脂寡糖的含量或组成变化无关，脂寡糖含有2.9、3.7、4.3和4.8 kDa的部分。在铁限制淋球菌的十二烷基肌氨酸钠纯化外膜中可检测到额外的蛋白质，但在胱氨酸或葡萄糖限制的细菌中也可检测到几种分子量与文献中描述的铁限制淋球菌相似的蛋白质。
