Bjorn M J, Sokol P A, Iglewski B H
J Bacteriol. 1979 Apr;138(1):193-200. doi: 10.1128/jb.138.1.193-200.1979.
The effect of the iron content of the medium on the yields of extracellular products by seven distinct strains of Pseudomonas aeruginosa was examined. All strains showed at least an 85% decrease in toxin A yields when grown in medium containing 5.0 mug of iron per ml (high iron) as compared to 0.05 mug/ml (low iron), whereas bacterial growth increased approximately twofold. During the course of examining extracellular products produced by P. aeruginosa, we found many strains that produced an extracellular factor which agglutinated erythrocytes. This hemagglutinin was nondialyzable, heat stable, and resistant to Pronase and trypsin. The effect of iron on extracellular yields of hemagglutinin was strain dependent; four of seven strains showed decreases in hemagglutinin yields in high-iron medium. Similarly, the effect of increasing the iron concentration of the growth medium on yields of total extracellular proteases or on elastase was strain dependent. The amount of total extracellular protein was decreased by at least 31% in the high-iron medium for all strains of P. aeruginosa examined. Detailed studies on one strain (WR-9) showed that, in the presence of increasing amounts of iron in the medium, the extracellular yields of toxin A, protease, and hemagglutinin were decreased in a similar manner. In addition, the kinetics of release of these extracellular products were similar at a given iron concentration. Thus it appears that the yields of other extracellular products of P. aeruginosa besides toxin A are influenced by the concentration of iron in the growth medium.
研究了培养基中铁含量对7种不同铜绿假单胞菌菌株细胞外产物产量的影响。与每毫升含0.05微克铁（低铁）的培养基相比，所有菌株在每毫升含5.0微克铁（高铁）的培养基中生长时，毒素A产量至少降低85%，而细菌生长增加约两倍。在研究铜绿假单胞菌产生的细胞外产物过程中，我们发现许多菌株产生了一种能凝集红细胞的细胞外因子。这种血凝素不能透析、热稳定，且对链霉蛋白酶和胰蛋白酶有抗性。铁对血凝素细胞外产量的影响因菌株而异；7个菌株中有4个在高铁培养基中血凝素产量降低。同样，生长培养基中铁浓度增加对总细胞外蛋白酶或弹性蛋白酶产量的影响也因菌株而异。在所检测的所有铜绿假单胞菌菌株中，高铁培养基中总细胞外蛋白量至少减少31%。对一个菌株（WR-9）的详细研究表明，在培养基中铁含量增加的情况下，毒素A、蛋白酶和血凝素的细胞外产量以类似方式降低。此外，在给定铁浓度下，这些细胞外产物的释放动力学相似。因此，似乎除毒素A外，铜绿假单胞菌其他细胞外产物的产量也受生长培养基中铁浓度的影响。
