Vaca S, Pérez S, Martínez G, Enriquez F
Escuela Nacional de Estudios Profesionales Iztacala, Universidad Nacional Autónoma de México, Tlanepantla, Edo. de México.
Rev Latinoam Microbiol. 1993 Jul-Sep;35(3):251-7.
FIZ15 phage of Pseudomonas aeruginosa causes lysogenic conversion in PAO1 strain. Lysogen shows increased adhesion to human buccal epithelial cells, increased resistance to 75 percent human serum bactericidal effect, and streptomycin resistant. These phenotypes apparently are due to a phage-induced superficial change on its own bacterial receptor, which probably is the O-antigen. In order to begin FIZ15 characterization, nitrous acid-induced clear-plaque mutants were obtained. They belonged to three complementation groups and mapping by two factor crosses revealed that they were closely linked. In a search for phage mutants that do not cause lysogenic conversion, two streptomycin-sensitive mutants were obtained by ethyl methane sulphonate mutagenesis of PAO1 lysogenic for FIZ15 (PIZ15 strain). One mutant (con1) showed and adhesion value similar to that of PAO1 and the other (con2) had an adhesion twofold and 1.3 times greater than PAO1 and PIZ15, respectively. con1 did not show increased serum resistance, whereas con2 was as resistant as PIZ15. Phages were isolated from the streptomycin sensitive mutants and used to relisogenize PAO1 to obtain the con1d and con2d lysogens. Adhesion and serum sensitivity of con1d was identical to that of PAO1 but con2d behaves like PIZ15. FIZ15 phage was unable to adsorb to PIZ15, con2 and con2d. On the other hand, FIZ15 phage adsorbs well to con1 and con1d but not to PIZ15. These results suggest that con1 mutation lies on the phage chromosome and con2 on the bacterial one. Finally, adhesion of all lysogens and PAO1 was stimulated 2-3 times by KCl and this effect was suppressed by and oxidative phosphorylation uncoupler.
铜绿假单胞菌的FIZ15噬菌体可导致PAO1菌株发生溶原性转化。溶原菌对人颊上皮细胞的黏附性增强，对75%人血清杀菌作用的抗性增强，且具有链霉素抗性。这些表型显然是由于噬菌体诱导其自身细菌受体发生表面变化所致，该受体可能是O抗原。为了开始对FIZ15进行特性分析，获得了亚硝酸诱导的透明噬菌斑突变体。它们属于三个互补群，通过双因子杂交作图显示它们紧密连锁。在寻找不引起溶原性转化的噬菌体突变体时，通过对FIZ15溶原性的PAO1（PIZ15菌株）进行甲磺酸乙酯诱变，获得了两个链霉素敏感突变体。一个突变体（con1）的黏附值与PAO1相似，另一个突变体（con2）的黏附性分别比PAO1和PIZ15高两倍和1.3倍。con1未表现出血清抗性增加，而con2与PIZ15一样具有抗性。从链霉素敏感突变体中分离出噬菌体，用于再次使PAO1溶原化以获得con1d和con2d溶原菌。con1d的黏附性和血清敏感性与PAO1相同，但con2d的行为与PIZ15相似。FIZ15噬菌体无法吸附到PIZ15、con2和con2d上。另一方面，FIZ15噬菌体能很好地吸附到con1和con1d上，但不能吸附到PIZ15上。这些结果表明，con1突变位于噬菌体染色体上，而con2突变位于细菌染色体上。最后，KCl可使所有溶原菌和PAO1的黏附性提高2至3倍，而这种效应可被氧化磷酸化解偶联剂抑制。
