野油菜黄单胞菌低温分泌黄原胶微细结构特征和化学特性

THE TINY STRUCTURE AND CHEMICAL PROPERTY FXANTHANSECRED BY XANTHOMONAS CAMPESTRIS UNDER LOW TEMPERATURE

首次发现２８℃培养至对数期且未分泌黄原胶的野油菜黄单胞菌（Ｘａｎｔｈｏｍｏｎａｓ ｃａｍｐｅｓｔｒｉｓ）移 至４℃低温培养仍合成分泌黄原胶。黄原胶低温分泌最微细的结构单位是微丝，多根微丝进一步组成 纤维、类似双螺旋或纤维束等级结构形式。低温分泌的黄原胶与２８℃常温分泌的黄原胶相比有相同 的化学组成与结构，但分子量、丙酮酸含量低。

We first find Xanthomonas campestris N. K-01 which don' t produce xanthan at 28℃ can synthesize and secrete the xanthan under low temperature (4℃). Little string is the most minute unit of the secreted under low temperature. Many little strings ecreted by bacterium cell extend to form a wider xanthan fiber. When depart from cell, xanthan fiber either twine to form double helix of bundle together. They are both advanced structures of the xanthan strings. Xanthan secreted under 4℃ has the same chemical composition and structure as that under 28℃, but lower moleculer weight and lower pyruvate content.