Höfte M, Buysens S, Koedam N, Cornelis P
Laboratorium voor Fytopathologie & Fytovirologie, Universiteit Gent, Belgium.
Biometals. 1993 Summer;6(2):85-91. doi: 10.1007/BF00140108.
Zinc concentrations ranging between 0.1 and 1 mM only slightly reduced maximal growth of wild-type Pseudomonas aeruginosa 7NSK2 in iron-limiting casamino acid medium, but had a clear negative effect on the growth of mutant MPFM1 (pyoverdin negative) and especially mutant KMPCH (pyoverdin and pyochelin negative). Production of pyoverdin by wild-type strain 7NSK2 was significantly increased in the presence of 0.5 mM zinc and could not be repressed by iron even at a concentration of 100 microM. Siderophore detection via isoelectrofocusing revealed that mutant KMPCH did not produce any siderophores, while mutant MPFM1 overproduced a siderophore with an acidic isoelectric point, most likely pyochelin. Pyochelin production by MPFM1 was stimulated by the presence of zinc in a similar way as pyoverdin for the wild-type. Analysis of outer membrane proteins revealed that three iron regulated outer membrane proteins (IROMPs) (90, 85 and 75 kDa) were induced by iron deficiency in the wild-type, while mutants were found to have altered IROMP profiles. Zinc specifically enhanced the production of a 85 kDa IROMP in 7NSK2, a 75 kDa IROMP in MPFM1 and a 90 kDa IROMP in KMPCH.
在铁限制的酪蛋白氨基酸培养基中，锌浓度在0.1至1 mM之间仅略微降低了野生型铜绿假单胞菌7NSK2的最大生长，但对突变体MPFM1（绿脓菌素阴性）尤其是突变体KMPCH（绿脓菌素和绿脓杆菌素阴性）的生长有明显的负面影响。在存在0.5 mM锌的情况下，野生型菌株7NSK2的绿脓菌素产量显著增加，即使在100 microM的浓度下铁也无法抑制其产生。通过等电聚焦进行的铁载体检测表明，突变体KMPCH不产生任何铁载体，而突变体MPFM1过量产生一种具有酸性等电点的铁载体，很可能是绿脓杆菌素。与野生型的绿脓菌素一样，锌的存在以类似方式刺激了MPFM1的绿脓杆菌素产生。外膜蛋白分析表明，野生型中三种铁调节外膜蛋白（IROMPs）（90、85和75 kDa）由缺铁诱导，而发现突变体具有改变的IROMP图谱。锌特异性增强了7NSK2中85 kDa IROMP的产生、MPFM1中75 kDa IROMP的产生以及KMPCH中90 kDa IROMP的产生。
