• 作者： 林幸美；曾義雄
• 作者服務機構： 國立中興大學摘物學系
• 中文摘要： Xanthomonas oryzae在液體培養基中生長至靜止期時，?開始聚集細胞外多醣質(Exopolysaccharide，簡稱eps)，其聚集量在48?72小時之間達到極限。在一含有55mM磷酸鹽，pH7.15之基礎培養基內加予蔗糖、葡萄糖、甘露糖或半 乳糖?碳源以及以?酸鈉與半胱胺酸?氮源，於29℃下振溫培養可使菌體細胞與EPS之?量達到最高。以木糖為碳源亦 可得到良好之生長，但其供EPS合成之效果僅約?蔗糖之30﹪ 。受試離子中，鎂?供生長與EPS合成之必需，而且無法 由錳離子取代。缺鉀時生長不受.影響，但EPS之合成則受嚴重抑制。極低濃度之銅、?、汞離子或Tween 80?能對EPS 之合成?生抑制作用。其抑制可達50?60﹪。在靜止期前加入蛋白質合成抑制劑-氯絲黴素於培養液?能抑制EPS之合 成，但於停止生長後才加入者則否。此照顯示EPS之合成系統須有新合成之蛋白參予才能開始作用。
• 英文摘要： In a culture of Xanthomonas oryzae strain 604, exopolysaccharide (eps) started to accumulate at stationary phase and reached the greatest amount by 48-72 hr. Both cell yield and eps production performed best in the basal medium containing 55 mM phosphate, pH 7.15, supplemented with sucrose, glucose, mannose or galactose and Na-glutamate, at 29蚓 and aerated by shaking. Xylose also supported good growth; however, on this pentose the capacity of the cells to produce eps was about 30% of that observed on sucrose. Among the ions tested, Mg+t was essential for growth and eps production, and could not be replaced by Mn++. Deprivation of K+ strongly inhibited eps synthesis but not the growth. Very low concentrations of Cu++, Zn++, Hg++ or Tween 80 inhibited eps synthesis by 50-60%. Addition of chloramphenicol to growing cultures revealed that de novo synthesis of protein was necessary for eps synthesizing system to get to function.
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