Mechanism of Bacterial Cell Flocculation by Extracellular Materials from Nocardia Amarae.

发现amarae Nocardia YK1产生细菌絮凝诱导物质FIX：絮凝诱导剂x。FIX对增殖细胞有絮凝作用；静息条件下，固定诱导的絮凝反应减慢。FIX对革兰氏阴性至阳性菌的絮凝诱导具有广谱性。在FIX的作用下，环裂无色杆菌IAM1013、钙酸不动杆菌IAM1517、枯草芽孢杆菌IAM1069、大肠杆菌iam600 -1、大肠杆菌IAM1239、黄疸杆菌IAM1667、肺炎克雷伯菌IAM1102、黄疸微球菌IAM1313和恶臭假单胞菌IAM1002分别形成絮凝体，蜡状芽孢杆菌IAM1029不形成絮凝体。对诺卡菌YK1产生的生物絮凝剂FIX进行了分选，发现絮凝剂是三种以上物质的混合物。虽然单个组分在pH 5 ~ 7时不表现出絮凝剂的能力，但在pH 7时，各组分混合后出现了协同絮凝作用。红外分光光度分析表明，该组分的主要成分可能为多肽。酶解肽段导致絮凝活性消失。

The fact that Nocardia amarae YK1 produced bacterial flocculation-inducing substances (FIX : Flocculation Inducer-X) was discovered. FIX had a function of flocculating the proliferating cells ; FIX-induced flocculation was retarded in resting cell conditions.FIX had a broad spectrum on flocculation induction from gram-negative to -positive bacteria. In the presence of FIX, Achromobacter cycloclastus IAM1013, Acinetobacter calcoaceticus IAM1517, Bacillus subtilis IAM1069, Escherichia coliC600-1, E. coli IAM1239, Flavobacterium lutescens IAM1667, Klebsiella pneumoniae IAM1102, Micrococcus luteus IAM1313 and Pseudomonas putida IAM1002 formed flocs, respectively, though B. cereus IAM1029 exhibited no flocculation.The fractionation of bioflocculant FIX produced by Nocardia amarae YK1 revealed that the flocculant was a mixture of more than three substances. Although individual fractions did not exhibit the ability of flocculant at pH 5 to 7, synergetic flocculation was observed at pH 7 after mixing the fractions. Infrared spectrophotometry suggested that the chief components of the frctions might be peptides. Enzymatic digestion of peptide moiety results in disappearance of flocculation activity.