MECHANISM OF ENHANCEMENT OF MICROBIAL CELL HYDROPHOBICITY BY CATIONIC POLYMERS
MECHANISM OF ENHANCEMENT OF MICROBIAL CELL HYDROPHOBICITY BY CATIONIC POLYMERS
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DOI：
10.1128/jb.172.10.5650-5654.1990
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发表时间：
1990-10-01
影响因子：
3.2
通讯作者：
ROSENBERG, M
中科院分区：
文献类型：
--
作者：
GOLDBERG, S;DOYLE, RJ;ROSENBERG, M
聚阳离子聚合物在促进细胞与不同表面的黏附方面的作用已被注意到，但以前的研究未能描述这种黏附的机制。在本研究中，测试了三种聚阳离子聚合物(壳聚糖、聚L赖氨酸和溶菌酶)对微生物疏水性的影响，通过对碳氢化合物和聚苯乙烯的粘附性来确定。测试菌株(大肠杆菌、白色念珠菌和来自醋酸钙不动杆菌RAG-1的非疏水突变体MR-481)在不同聚阳离子存在下与十六烷旋转，并用比浊法测量黏附程度。在低浓度的壳聚糖(125至250微克/毫升)存在下，所有三个测试菌株的粘附率都从接近零的值上升到90%以上。粘附性是通过壳聚糖直接吸附到细胞表面而发生的，因为在聚合物存在下预培养的大肠杆菌细胞具有更高的粘附性，而经壳聚糖预处理的十六烷液滴随后无法与未处理的细胞结合。无机阳离子(Na+，Mg2+)抑制了壳聚糖介导的大肠杆菌与十六烷的黏附，可能是通过干扰导致聚合物吸附到细菌表面的静电相互作用来实现的。壳聚糖同样促进了大肠杆菌与聚苯乙烯的粘附性，其浓度略高于介导性粘附性十六烷的浓度。多聚L赖氨酸也促进微生物对十六烷的黏附，尽管在浓度上略高于壳聚糖。为了研究阳离子蛋白溶菌酶的影响，在0度条件下进行了粘附性研究。C(防止酶活性)，使用正辛烷作为测试碳氢化合物。当每毫升溶菌酶的用量为80ug时，大肠杆菌的粘附性增加了70%。当大肠杆菌表面带负电荷的羧酸残基被带正电荷的氨基取代时，所得到的细胞变得高度疏水，即使在没有聚阳离子的情况下也是如此。因此，在聚阳离子存在的情况下观察到的微生物细胞的“疏水性”可能是由于表面电负性的丧失。这些数据表明，聚阳离子聚合物的疏水性增强是一种普遍现象。
Polycationic polymers have been noted for their effects in promoting cell adhesion to various surfaces, but previous studies have failed to describe a mechanism dealing with this type of adhesion. In the present study, three polycationic polymers (chitosan, poly-L-lysine, and lysozyme) were tested for their effects on microbial hydrophobicity, as determined by adhesion to hydrocarbon and polystyrene. Test strains (Escherichia coli, Candida albicans, and a nonhydrophobic mutant, MR-481, derived from Acinetobacter calcoaceticus RAG-1) were vortexed with hexadecane in the presence of the various polycations, and the extent of adhesion was measured turbidimetrically. Adhesion of all three test strains rose from near zero values to over 90% in the presence of low concentrations of chitosan (125 to 250 .mu.g/ml). Adhesion occurred by adsorption of chitosan directly to the cell surface, since E. coli cells preincubated in the presence of the polymer were higher adherent, whereas hexadecane droplets pretreated with chitosan were subsequently unable to bind untreated cells. Inorganic cations (Na+, Mg2+) inhibited the chitosan-mediated adhesion of E. coli to hexadecane, presumably by interfering with the electrostatic interactions responsible for adsorption of the polymer to the bacterial surface. Chitosan similarly promoted E. coli adhesion to polystyrene at concentrations slightly higher than those which mediated adhesion to hexadecane. Poly-L-lysine also promoted microbial adhesion to hexadecane, although at concentrations somewhat higher than those observed for chitosan. In order to study the effect of the cationic protein lysozyme, adhesion was studied at 0.degree. C (to prevent enzymatic activity), using n-octane as the test hydrocarbon. Adhesion of E. coli increased by 70% in the presence of 80 .mu.g of lysozyme per ml. When the negatively charged carboxylate residues on the E. coli surface were substituted for positively charged ammonium groups, the resulting cells became highly hydrophobic, even in the absence of polycations. The observed "hydrophobicity" of the microbial cells in the presence of polycations is thus probably due to a loss of surface electronegativity. The data suggest that enhancement of hydrophobicity by polycationic polymers is a general phenomenon.