Ashton D H, Busta F F, Warren J A
Appl Microbiol. 1968 Apr;16(4):628-35. doi: 10.1128/am.16.4.628-635.1968.
Growth of Bacillus stearothermophilus strain NCA 1518 Smooth in Dextrose Tryptone Agar (DTA) was inhibited by sodium caseinate. Binding studies indicated that sodium caseinate, when present in DTA, had the capacity to effect an iron deficiency which could cause inhibition of growth. Additions of essential cations, iron (1 mM), calcium (5 mM), magnesium (10 mM), or hydrogen ion (pH 5.7), relieved inhibition. Responses to and interactions among these relief factors were analyzed statistically. Equations were fitted to the data and were used to estimate responses to all treatment combinations within the ranges tested. Results from these studies indicated that calcium, magnesium, and hydrogen ion acted by decreasing the binding capacity of the protein for iron, rendering this metal available for metabolic needs. Evidence was obtained that ferrous rather than ferric iron was the limiting factor in DTA containing sodium caseinate.
嗜热脂肪芽孢杆菌菌株NCA 1518 Smooth在葡萄糖胰蛋白胨琼脂（DTA）中的生长受到酪蛋白酸钠的抑制。结合研究表明，当酪蛋白酸钠存在于DTA中时，它有能力导致铁缺乏，从而抑制生长。添加必需阳离子，铁（1 mM）、钙（5 mM）、镁（10 mM）或氢离子（pH 5.7），可缓解抑制作用。对这些缓解因子之间的反应和相互作用进行了统计分析。将方程拟合到数据中，并用于估计在所测试范围内所有处理组合的反应。这些研究结果表明，钙、镁和氢离子的作用是降低蛋白质对铁的结合能力，使这种金属可用于代谢需求。有证据表明，在含有酪蛋白酸钠的DTA中，亚铁而非三价铁是限制因素。
