Kobayashi Yosuke, Iwata Hisashi, Yoshida Junjiro, Ogihara Jun, Kato Jun, Kasumi Takafumi
College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa 252-0880, Japan.
College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa 252-0880, Japan.
J Biosci Bioeng. 2015 Oct;120(4):405-10. doi: 10.1016/j.jbiosc.2015.02.014. Epub 2015 Mar 17.
Moniliella megachiliensis, the osmo-tolerant basidiomycetous yeast was found to accumulate intracellularly energy-storing carbohydrates (trehalose and glycogen) along with polyols (glycerol and erythritol) up to stationary growth phase. In trehalose-loaded cell, osmotic-stress resulted in the rapid generation of glycerol, and oxidative stress with menadione resulted in the rapid generation of erythritol. Under either of these conditions, the levels of the energy-storing carbohydrates were depleted, while little glucose uptake was observed. These results suggested that the intracellular pools of trehalose and glycogen were rapidly converted to glycerol in response to osmotic stress, and to erythritol in response to oxidative stress and altered redox balance. Expression of tps1 encoding trehalose synthetic enzymes paralleled trehalose accumulation in the cell during the culture in 2% glucose, in contrast, expression of tpp1 or tpp2 encoding trehalose-6-phosphate phosphatase was little increased under the same condition. Expression of tre (tre1/tre2) encoding trehalose hydrolase (trehalase) increased with time associated with depletion of trehalose during oxidative stress. From these results, we concluded that glycerol and erythritol, the compatible solutes in M. megachiliensis were metabolically interrelated to energy-storing carbohydrates such as trehalose or glycogen during conditions of osmotic or oxidative stress.
巨大智利念珠菌是一种耐渗透压的担子菌酵母，在稳定生长期之前，其细胞内会积累储能碳水化合物（海藻糖和糖原）以及多元醇（甘油和赤藓糖醇）。在负载海藻糖的细胞中，渗透压胁迫会导致甘油快速生成，而甲萘醌引发的氧化应激会导致赤藓糖醇快速生成。在这两种情况下，储能碳水化合物的水平都会降低，同时观察到葡萄糖摄取很少。这些结果表明，细胞内的海藻糖和糖原池会在渗透压胁迫下快速转化为甘油，在氧化应激和氧化还原平衡改变时快速转化为赤藓糖醇。在2%葡萄糖培养基中培养期间，编码海藻糖合成酶的tps1的表达与细胞中海藻糖的积累平行，相反，在相同条件下，编码海藻糖-6-磷酸磷酸酶的tpp1或tpp2的表达几乎没有增加。编码海藻糖水解酶（海藻糖酶）的tre（tre1/tre2）的表达随着氧化应激期间海藻糖的消耗而增加。从这些结果中，我们得出结论，在渗透压或氧化应激条件下，巨大智利念珠菌中的相容性溶质甘油和赤藓糖醇与海藻糖或糖原等储能碳水化合物在代谢上相互关联。
