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  • 學位論文

探討牛樟芝菌絲體中 4-acetylantroquinonol B 生合成途徑 polyketide pathway 下游步驟之機制

The Role of Downstream Steps of Polyketide Pathway in the Biosynthesis of 4-AAQB during Submerged Fermentation of Antrodia cinnamomea

指導教授 : 蔣丙煌
本文將於2025/08/16開放下載。若您希望在開放下載時收到通知,可將文章加入收藏

摘要


牛樟芝 (Antrodia cinnamomea) 是台灣原生種真菌,其液態發酵產出之菌絲體含有高量之具有抗癌功效的泛醌類 antroquinonol (AQ) 及 4-acetylantroquinonol B (4-AAQB) ,其中 4-AAQB是菌絲體中主要之抗肝癌化合物。本研究室過去曾利用超音波作為外力刺激,發現可有效促進液態發酵牛樟芝菌絲體中 4-AAQB 生合成,但是不能刺激 AQ 的生合成。本研究再次證實此一結果的正確性,而其原因可能是由於生合成途徑中的酵素活性受超音波改變所致。本研究原本預期,在可促進 4-AAQB 生合成的超音波處理條件下,牛樟芝應能更有效地運用六碳環前驅物 CoQ0 生合成 4-AAQB ,但結果卻不如預期,在給予超音波刺激下,外加的 CoQ0 無法有效被用於 4-AAQB 生合成。由 LC-MS-MS 分析則可推論, CoQ0 應可經由 polyketide pathway 被代謝為 CoQ3 與 CoQ3B ,故 CoQ0 應同時是 AQ 與 4-AAQB 的六碳環前驅物,而添加 CoQ0 無法提升 4-AAQB 產量可能是由於菌絲體中累積的 CoQ3B 與 AQB 無法進一步被轉為 4-AAQB 所致。此外,本研究也推論,超音波處理對 polyketide pathway 的主要影響,是能促進其中間產物 5-DMQ3B 轉為 CoQ3B 的步驟,並能抑制其下游產物 CoQ3 轉為 AQ 之步驟。若同時添加 CoQ0 並使用超音波處理,超音波的介入則可能會使部分外加的 CoQ0 被轉而用於其他代謝途徑而造成 CoQ3B 生合成減少,並可能抑制 5-DMQ3 與 6-DMQ3 轉為 CoQ3 之步驟,進而抑制 4-AAQB 及 AQ 的生合成。

並列摘要


Antrodia cinnamonea is an endemic fungus of Taiwan that specifically inhabits the decayed inner wall of stout camphor trees. The mycelia of A. cinnamonea produced through submerged fermentation are rich in anti-hepatic compounds such as antroquinonol (AQ) and 4-acetylantroquinonol B (4-AAQB), and the latter has been proven to possess the most potent anti-hepatocellular carcinoma function. Our laboratory has used ultrasound as an external force to promote 4-AAQB biosynthesis, and this study further confirmed that ultrasound treatment indeed could increase 4-AAQB production in the mycelia, but not AQ yield. We suspect that the enzymes involved in the biosynthesis of these two compounds responded differently to ultrasound treatment. We postulated that supplementation of the probable precursor CoQ0 along with ultrasound treatment during submerged fermentation should be able to to further stimulate the fungus to utilize CoQ0 to synthesize 4-AAQB. However, the results showed that ultrasound treatment with CoQ0 supplementation could not increase the yield of 4-AAQB. According to the results of LC-MS-MS analysis, CoQ0 was converted to CoQ3 and CoQ3B, therefore, it shuld be the precursor of both AQ and 4-AAQB. The fact that supplementation of CoQ0 could not increase 4-AAQB yield might be due to the accumulation of CoQ3B and AQB, because they could not further concvert to 4-AAQB. We could also deduce that the major influence of ultrasound treatment on polyketide pathway is to stimulate the intermediate 5-DMQ3B to convert to CoQ3B. Ultrasound treatment might also inhibit CoQ3 to convert to AQ. We also suspect that supplementation of CoQ0 along with ultrasound treatment would stimulate other metabolic pathways to utilize the CoQ0, which decreases the biosynthesis of CoQ3B, and thus decreases 4-AAQB yield. This combined treatment might also inhibit 5-DMQ3 and 6-DMQ3 to convert to CoQ3, and thus decreases AQ yield.

參考文獻


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