Bifidobacterium longum之生長特性及放射線耐受性

1洪茂欽

慈濟技術學院放射技術系

2廖明雄

慈濟醫學中心放射腫瘤科

3許文林

慈濟醫學中心放射腫瘤科

4蔡永川

慈濟醫學中心檢驗科

摘　要

本研究分析Bifidobacterium longum（長雙歧桿菌）在不同培養基及不同氣體培養環境下的生長增殖情形，並分析其對高能量X光的耐受程度。結果發現Bifidobacterium longum最容易在無氧的TYL培養基中生長增殖，從生長曲線得知，12小時前為遲緩期，12至36小時為對數生長期，36小時以後為穩定期。無氧環境下，在TYL培養基中生長的比在TYG培養基中快且多，而在含氧環境下則都無法生長。此外，從本研究中得知Bifidobacterium longum可耐受高達80 Gy的輻射劑量（單次照射，存活分率為22 ％；以分次照射每次給予2 Gy來估算，存活分率為67％），此劑量為臨床放射治療一般給予的總劑量，因此證實Bifidobacterium longum有很大的潛力做為癌症基因治療合併放射治療的載具，本研究也是首篇調查Bifidobacterium longum對放射線耐受性的研究。

關鍵字：Bifidobacterium longum、生長曲線、放射線耐受性



The Growth Characteristics and the Tolerance of Radiation for Bifidobacterium longum

1Mao-Chin Hung

Department of Radiological Technolongy

Tzu Chi College of Techology

2Ming-Hsiung Liaw

Department of Radiation Oncdogy

Tzu Chi General Hospital

3Wen-Lin Hsu

Department of Radiation Oncdogy

Tzu Chi General Hospital

4Yeong-Chu Tsai

Department of Pathology

Tzu Chi General Hospital

Abstract

The growth curves of Bifidobacterium longum in TYL and TYG media under the aerobic or anaerobic conditions, and its tolerance of high energy X-ray irradiation were investigated in this study. The result showed that Bifidobacterium longum grows and proliferates best in anaerobic TYL medium. It belongs to lag phase before 12 hours, log phase during 12 and 36 hours, and stationary phase after 36 hours. Bifidobacterium longum can also form colonies in anaerobic TYG medium after 5 days. However, the size and number of colonies are less than which in anaerobic TYL medium. It can not grow in aerobic TYL and TYG media. Bifidobacterium longum can tolerate radiation dose as high as 80 Gy, which is the total dose in clinical radiotherapy. Therefore, Bifidobacterium longum has the potential to be the vector for cancer gene therapy combining radiotherapy. Besides, this is the first study to investigate the tolerance of X-ray radiation for Bifidobacterium longum.

Key words:Bifidobacterium longum , growth curves, tolerance of X-ray radiation