Significant structural change in both O- and N-linked carbohydrate moieties of the antigenic galactomannan from Aspergillus fumigatus grown under different culture conditions
Significant structural change in both O- and N-linked carbohydrate moieties of the antigenic galactomannan from Aspergillus fumigatus grown under different culture conditions
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DOI：
10.1093/glycob/cwu091
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发表时间：
2015-01-01
期刊：
影响因子：
4.3
通讯作者：
Shibata, Nobuyuki
中科院分区：
文献类型：
--
作者：
Kudoh, Atsushi;Okawa, Yoshio;Shibata, Nobuyuki
侵袭性曲霉病是免疫功能低下患者发病和死亡的重要原因。这种感染的诊断通常采用酶免疫测定（EIA），一种高度敏感和特异性的系统，检测患者血清中的循环半乳甘露聚糖。虽然有许多烟曲霉半乳甘露聚糖的结构研究，在这些结果中存在一些不一致。本研究中，为了阐明半乳甘露聚糖的生长条件和结构之间的关系，我们培养了A。使用两种不同的酵母/真菌培养基，即酵母提取物-蛋白胨-葡萄糖（YPD）培养基和酵母氮基（YNB）培养基，将所述菌株接种到烟曲霉中。半乳甘露聚糖从所得的培养上清液制备的结构特征的H-1和C-13核磁共振，甲基化分析，乙酰化和α-甘露糖苷酶降解。这些测定揭示，来自YPD培养物的半乳甘露聚糖在O-和N-连接的碳水化合物部分中具有短的β-1，5-连接的半乳呋喃糖（Galf）寡糖链，而来自YNB培养物的半乳甘露聚糖掺入长的Galf寡糖链。基于EIA诊断系统，来自两种培养条件的半乳甘露聚糖的反应性显著不同。我们还证明了存在一种新的Galf含支链寡糖的O-连接的部分。
Invasive aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Diagnosis of this infection frequently employs detection of the circulating galactomannan in the patient serum using enzyme immunoassay (EIA), a highly sensitive and specific system. Although there are many structural studies of the galactomannan of Aspergillus fumigatus, some inconsistencies are present in these results. In this study, to clarify the relationship between the growth conditions and structure of the galactomannans, we cultured A. fumigatus using two distinct yeast/fungal cultivation media, i.e. the yeast extract-peptone-dextrose (YPD) medium and yeast nitrogen base (YNB) medium. Galactomannans prepared from the resulting culture supernatants were structurally characterized by H-1 and C-13 nuclear magnetic resonance, methylation analysis, acetolysis and alpha-mannosidase degradation. These assays revealed that the galactomannan from the YPD cultivation had short beta-1,5-linked galactofuranose (Galf) oligosaccharide chains in both the O- and N-linked carbohydrate moieties, while the galactomannan from the YNB cultivation incorporated long Galf oligosaccharide chains. The galactomannans derived from the two culture conditions significantly differed in reactivity based on the EIA diagnostic system. We also demonstrated the presence of a novel Galf-containing branched oligosaccharide in the O-linked moiety.