摘要
用两种方法分别洗除菌体胞外多糖(EPS)和脂多糖(LPS),经在大白菜幼苗上测定表明,菌体洗除 LPS 后对寄主根表的吸附能力明显减弱,吸附菌量随无 LPS 的菌体在混合接种体中比例的增高而降低,在无 LPS 的菌体接种体中加入 LPS 提取物,可使吸附能力恢复到正常水平;平行测定的 EPS 不发生上述影响。用 EPS 和 LPS 对根表进行预处理,均可明显抑制完整菌体(不洗,含 EPS 和 LPS)和无 EPS 的菌体对根表的吸附,但只有 LPS 预处理使无LPS 的菌体吸附量提高2—3倍。用大白菜对该菌的专化性细菌凝集素 Agin-SD60所作的菌体凝集试验表明,菌体洗除 LPS 后不再被 Agin-SD60所凝集。根据以上结果认为,菌体脂多糖在大白菜软腐欧文氏菌与寄主的接触识别中可作为细菌识别子起作用。
The cells of soft rot bacterium,Erwinia carotovora subsp,carotovora,were washedwith two methods to remove their extracellular saccharide(EPS)and lipopolysaccharide(LPS)and then inoculated to roots of Chinese cabbage seedlings,for testifying their adsorption on rootcells and root hairs.The bacterial numbers adsorbed irreversibly were detected,and ranged from3.63×10~7 CFU·g^(-1) to 1.32×10~8CFU·g^(-1) on ro(?)t cells and from 70bac.cm·cm^(-2) to 600bac·(?)m^(-2)on root hairs when the intact(unwashed,and EPS-and LPS-containing)bacteria were used asinocula at about 10~8CFU·ml^(-1).The LPS-free bateria showed about 92—97% decrease in amountof adsorbed bacteria in comparison with those of intact bacteria.The decrease degree of bacte-rial adsorption increased with the increment of LPS-free bacteria in the combined inoculum ofthem with intact ones.The adsorption ability of LPS-free bacteria could be recovered by add-ing purified LPS in their suspension.The EPS was also tested by the methods mentioned abo-ve,and no conspicuous effects were given on the bacterial adsorption.The root pretreatmentswith purified EPS and LPS could inhibit the adsorption of both intact and EPS-free bacteria,while only the pretreatments with LPS could enhance adsorption of LPS-free bacteria by 2—3rimes.The Agin-SD60,an agglutinin from seedlings of Chinese cabbage,was used in a concen-tration of 0.5μg·ml_(-1) to examine the differences in agglutination of different types of the bac-terial cells in term of surface saccharides.The EPS-free bacteria were able to be agglutinatedby the agglutinin better than intact ones.No agglutination was detected in the LPS-free bac-teria.From these results,it is seemed that the bacetrial lipopolysaccharide functions as the cog-non in recognition between the soft rot erwinia and chinese cabbage.
出处
《微生物学报》
CAS
CSCD
北大核心
1993年第2期144-150,共7页
Acta Microbiologica Sinica
关键词
大白菜
软腐欧文氏菌
脂多糖
吸附
Soft rot erwinia
Chinese cabbage
Adsorption
Lipolpolysaccharide
