Hincha Dirk K, Rennecke Petra, Oliver Ann E
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany.
Eur Biophys J. 2008 Apr;37(4):503-8. doi: 10.1007/s00249-007-0245-0. Epub 2007 Dec 7.
Sugars play an important role in the desiccation tolerance of most anhydrobiotic organisms. It has been shown in previous studies that different structural families of oligosaccharides have different efficacies to interact with phospholipid headgroups and protect membranes from solute leakage during drying. Here, we have compared three families of linear oligosaccharides (fructans (inulins), malto-oligosaccharides, manno-oligosaccharides) for their chain-length dependent protection of egg phosphatidylcholine liposomes against membrane fusion. We found increased protection with chain length up to a degree of polymerization (DP) of 5 for malto-oligosaccharides, and a decrease for inulins and manno-oligosaccharides. Differential scanning calorimetry measurements showed that for all sugars the glass transition temperature (T(g)) increased with DP, although to different degrees for the different oligosaccharide families. Higher T(g) values resulted in reduced membrane fusion only for malto-oligosaccharides below DP5. Contrary to expectation, for inulins, manno-oligosaccharides and malto-oligosaccharides of a DP above five, fusion increased with increasing T(g), indicating that other physical parameters are more important in determining the ability of different sugars to protect membranes against fusion during drying. Further research will be necessary to experimentally define such parameters.
糖类在大多数脱水生物的耐干燥性中起着重要作用。先前的研究表明，不同结构家族的寡糖与磷脂头部基团相互作用以及在干燥过程中保护膜防止溶质泄漏的效果不同。在此，我们比较了三类线性寡糖（果聚糖（菊粉）、麦芽寡糖、甘露寡糖）对鸡蛋磷脂酰胆碱脂质体膜融合的链长依赖性保护作用。我们发现，麦芽寡糖在聚合度（DP）达到5之前，随着链长增加保护作用增强，而菊粉和甘露寡糖则降低。差示扫描量热法测量表明，对于所有糖类，玻璃化转变温度（T(g)）均随DP升高，尽管不同寡糖家族升高的程度不同。仅对于DP低于5的麦芽寡糖，较高的T(g)值导致膜融合减少。与预期相反，对于DP高于5的菊粉、甘露寡糖和麦芽寡糖，融合随着T(g)升高而增加，这表明在确定不同糖类在干燥过程中保护膜防止融合的能力方面，其他物理参数更为重要。需要进一步开展研究以通过实验确定此类参数。
