【研究發展處訊】

微生物學系陳宜龍助理教授發表最新期刊論文

Identification of essential β‐oxidation genes and corresponding metabolites for oestrogen degradation by actinobacteria

作者：Tsun-Hsien Hsiao, Tzong-Huei Lee, Meng-Rong Chuang, Po-Hsiang Wang, Menghsiao Meng, Masae Horinouchi, Toshiaki Hayashi, Yi-Lung Chen, Yin-Ru Chiang

Microbial biotechnology (SCI)

卷冊：15 期：3

頁碼：949-966

出版日期：Mar. 2022

Abstract

Steroidal oestrogens (C₁₈) are contaminants receiving increasing attention due to their endocrine-disrupting activities at sub-nanomolar concentrations. Although oestrogens can be eliminated through photodegradation, microbial function is critical for removing oestrogens from ecosystems devoid of sunlight exposure including activated sludge, soils and aquatic sediments. Actinobacteria were found to be key oestrogen degraders in manure-contaminated soils and estuarine sediments. Previously, we used the actinobacterium Rhodococcus sp. strain B50 as a model microorganism to identify two oxygenase genes, aedA and aedB, involved in the activation and subsequent cleavage of the estrogenic A-ring respectively. However, genes responsible for the downstream degradation of oestrogen A/B-rings remained completely unknown. In this study, we employed tiered comparative transcriptomics, gene disruption experiments and mass spectrometry-based metabolite profile analysis to identify oestrogen catabolic genes. We observed the up-regulation of thiolase-encoding aedF and aedK in the transcriptome of strain B50 grown with oestrone. Consistently, two downstream oestrogenic metabolites, 5-oxo-4-norestrogenic acid (C₁₇) and 2,3,4-trinorestrogenic acid (C₁₅), were accumulated in aedF- and aedK-disrupted strain B50 cultures. Disruption of fadD3 [3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP)-coenzyme A-ligase gene] in strain B50 resulted in apparent HIP accumulation in oestrone-fed cultures, indicating the essential role of fadD3 in actinobacterial oestrogen degradation. In addition, we detected a unique meta-cleavage product, 4,5-seco-estrogenic acid (C₁₈), during actinobacterial oestrogen degradation. Differentiating the oestrogenic metabolite profile and degradation genes of actinobacteria and proteobacteria enables the cost-effective and time-saving identification of potential oestrogen degraders in various ecosystems through liquid chromatography–mass spectrometry analysis and polymerase chain reaction-based functional assays.

釋放到環境中的雌性激素會干擾其它生物的生理代謝，因此被視為一種環境荷爾蒙。所以，雌性激素如何被微生物分解是生物復育重要的一環。本篇研究指出細菌降解雌性激素所涉及基因的種類，及產生何種中間代謝物。應用本研究結果將有助於找出不同環境中的雌激素分解菌。

文章網頁連結: https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/1751-7915.13921

研究事務組提醒：教師如有最新發表於AHCI、SSCI、SCI、EI、TSSCI、THCI、「東吳大學外語學門獎勵名單」之期刊論文，歡迎將相關資訊e-mail至rad@scu.edu.tw，研究發展處將會公告於校園頭條，以廣交流。

【文圖/研究事務組游晴如組員】