Fett W F, Wijey C, Lifson E R
U.S. Department of Agriculture, ARS, Eastern Regional Research Center, Philadelphia, Pennsylvania 19118.
FEMS Microbiol Lett. 1992 Dec 1;78(2-3):151-7. doi: 10.1016/0378-1097(92)90017-i.
Total genomic DNA of 13 pseudomonads representing rRNA homology groups I-IV were screened for sequences homologous to four Pseudomonas aeruginosa alginate (alg) genes by Southern hybridization. Biotinylated probes for three structural genes (algA, algC and algD) and one regulatory gene (algR1) were prepared. Genomic DNA of strains representing group I (P. syringae pv. glycinea, P. viridiflava and P. corrugata) hybridized with all four gene probes. Hybridizing fragments were of differing sizes, indicating that evolutionary divergence among group I members has occurred. P. corrugata has not been reported to synthesize alginate. Genomic DNA from representatives of groups II-IV gave no or very weak hybridization with the probes except for algC. This study indicates that the ability to produce alginic acid as an exopolysaccharide among the pseudomonads is restricted to members of rRNA homology group I in agreement with earlier physiological studies.
通过Southern杂交，对代表rRNA同源群I-IV的13株假单胞菌的全基因组DNA进行筛选，以寻找与4个铜绿假单胞菌藻酸盐（alg）基因同源的序列。制备了针对3个结构基因（algA、algC和algD）和1个调控基因（algR1）的生物素化探针。代表群I的菌株（大豆丁香假单胞菌丁香致病变种、绿黄假单胞菌和皱叶假单胞菌）的基因组DNA与所有4种基因探针杂交。杂交片段大小不同，表明群I成员之间发生了进化分歧。尚未报道皱叶假单胞菌能合成藻酸盐。除algC外，来自群II-IV代表菌株的基因组DNA与探针无杂交或杂交非常弱。这项研究表明，假单胞菌中产生藻酸作为胞外多糖的能力仅限于rRNA同源群I的成员，这与早期的生理学研究一致。
