Thomas K R, Davis B
Microbios. 1980;28(112):69-80.
The effect of various osmotica and lytic enzyme treatments, on the release of stable protoplasts from Aspergillus niger and two strains of Aspergillus fumigatus, has been investigated. Most osmotica supported protoplast release at a concentration of 0.6 M except for CaCl2 and Ca(NO3)2. Supplementation of 0.6 M KCl with 0.2 M CaCl2 enhanced release from both species, but depended upon strain of organism, concentration of osmoticum and enzyme system employed. More protoplasts were released at low concentrations of KCl and/or when chitinase was present in the digestion medium. This enhancement effect was concerned with the Ca2+ ion since addition of Ca(NO3)2 also gave a higher yield and EDTA severely depressed protoplast release. Further investigations suggested that the effect of Ca2+ was not primarily acting as a supplementary osmoticum or concerned with protoplast membrane stabilization. Experiments using 45CaCl2 showed that the enhancement effect was probably due to Ca2+ affecting chitinase activity.
研究了各种渗透压剂和裂解酶处理对黑曲霉和两株烟曲霉释放稳定原生质体的影响。除CaCl₂和Ca(NO₃)₂外，大多数渗透压剂在0.6 M浓度下均能支持原生质体释放。用0.2 M CaCl₂补充0.6 M KCl可增强两种菌的原生质体释放，但这取决于生物体的菌株、渗透压剂浓度和所用的酶系统。在低浓度KCl下和/或消化培养基中存在几丁质酶时，会释放出更多原生质体。这种增强作用与Ca²⁺离子有关，因为添加Ca(NO₃)₂也能获得更高的产量，而EDTA会严重抑制原生质体释放。进一步的研究表明，Ca²⁺的作用主要不是作为补充渗透压剂或与原生质体膜稳定有关。使用⁴⁵CaCl₂的实验表明，增强作用可能是由于Ca²⁺影响了几丁质酶的活性。
