Sakai Hiromichi, Kajiwara Susumu
Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, 226-8501, Japan.
Lipids. 2004 Jan;39(1):67-73. doi: 10.1007/s11745-004-1203-9.
The basidiomycetous mushroom Lentinula edodes (Shiitake) exhibits a unique process of cell differentiation termed "fruiting-body formation". To clarify the relationship between membrane lipids and fruiting-body formation in this fungus, we investigated variations in levels of phospholipids, cerebrosides, fatty acyl residues in the major phospholipids, and fatty acyl and sphingoid base residues in cerebrosides during vegetative growth and fruiting-body formation. PC, PE, and PS were the primary phospholipids in the cells of L. edodes. After a shift in growth temperature of L. edodes mycelia has been shifted from 25 to 18 degrees C, the proportion of unsaturated FA (UFA), such as linoleic acid (18:2) and oleic acid (18:1), increased. In contrast, during fruiting-body formation induced by the temperature downshift to 18 degrees C, 18:2 of PC in the primordia and fruiting bodies decreased, and the UFA of PE and 18:1 of PC increased compared with the proportions in mycelia growing at 18 degrees C. These results showed that the proportions of fatty acyl residues in PC and PE differed during fruiting-body formation in L. edodes. Moreover, the amount of cerebrosides in primordia increased compared with those in mycelia and fruiting bodies and, in these differentiating tissues, the proportion of 2-hydroxypentadecanoic acid increased whereas that of 2-hydroxyoctadecanoic acid decreased compared with that in the mycelia. However, the proportion of sphingoid base residues in cerebrosides did not change during fruiting-body formation in L. edodes.
担子菌香菇表现出一种独特的细胞分化过程，称为“子实体形成”。为了阐明这种真菌中膜脂与子实体形成之间的关系，我们研究了在营养生长和子实体形成过程中磷脂、脑苷脂、主要磷脂中的脂肪酰基残基以及脑苷脂中的脂肪酰基和鞘氨醇碱基残基水平的变化。磷脂酰胆碱（PC）、磷脂酰乙醇胺（PE）和磷脂酰丝氨酸（PS）是香菇细胞中的主要磷脂。香菇菌丝体的生长温度从25℃转变为18℃后，不饱和脂肪酸（UFA）如亚油酸（18:2）和油酸（18:1）的比例增加。相反，在温度降至18℃诱导子实体形成的过程中，原基和子实体中PC的18:2减少，与在18℃生长的菌丝体相比，PE的UFA和PC的18:1增加。这些结果表明，香菇在子实体形成过程中PC和PE中脂肪酰基残基的比例不同。此外，与菌丝体和子实体相比，原基中脑苷脂的含量增加，并且在这些分化组织中，与菌丝体相比，2-羟基十五烷酸的比例增加而2-羟基十八烷酸的比例降低。然而，香菇在子实体形成过程中脑苷脂中鞘氨醇碱基残基的比例没有变化。
