Witholt B, Boekhout M
Biochim Biophys Acta. 1978 Apr 4;508(2):296-305. doi: 10.1016/0005-2736(78)90332-2.
The restricted access of lysozyme to the murein layer of exponential phase Escherichia coli is enhanced considerably by osmotic shock. When cells suspended in Tris/EDTA/sucrose are diluted 11-fold in water or 10 mM EDTA in the presence of lysozyme, their susceptibility to lysozyme increases by a factor of 50--100, for both Escherichia coli JC411 and W3110, grown to the early exponential phase in unsuppleneted or supplemented minimal media, and in Brain Heart Infusion. Since an 11-fold dilution causes lysis of lysozyme spheroplasts, the effects of a 2-fold dilution have also been investigated. A 2-fold dilution of cell suspended in TrisEDTA/sucrose still increases their susceptibility to lysozyme by a factor of 10--50, but the resulting spheroplasts remain intact. EDTA is necessary to permit lysozyme access to the murein layer during the dilution, which is ineffective in the presence of 5 mM MgCl2. These results are discussed in terms of the formation of lysozyme spheroplasts from young Escherichia coli.
渗透压休克可显著增强溶菌酶对指数生长期大肠杆菌胞壁质层的限制性作用。当悬浮于Tris/EDTA/蔗糖中的细胞在溶菌酶存在的情况下用水或10 mM EDTA稀释11倍时，对于在未补充或补充了基本培养基以及脑心浸液中生长至早期指数生长期的大肠杆菌JC411和W3110而言，它们对溶菌酶的敏感性增加了50至100倍。由于11倍稀释会导致溶菌酶原生质球裂解，因此也研究了2倍稀释的效果。悬浮于TrisEDTA/蔗糖中的细胞进行2倍稀释后，其对溶菌酶的敏感性仍会增加10至50倍，但产生的原生质球保持完整。在稀释过程中，EDTA是使溶菌酶能够作用于胞壁质层所必需的，在5 mM MgCl2存在时该稀释无效。本文根据年轻大肠杆菌形成溶菌酶原生质球的情况对这些结果进行了讨论。
