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Competence in Genetic Transformation Related To Colony Type and Fimbriation in Three Species of Moraxella
Author(s) -
Bøvre Kjell,
Frøholm Leif Oddvar
Publication year - 1972
Publication title -
acta pathologica microbiologica scandinavica section b microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-5563
DOI - 10.1111/j.1699-0463.1972.tb00191.x
Subject(s) - biology , dna , streptomycin , transformation (genetics) , microbiology and biotechnology , agar plate , mutant , genetics , bacteria , gene , antibiotics
Non‐fimbriated or weakly fimbriated cells from non‐corroding colonies (N type) and strongly fimbriated cells from agar‐corroding and often spreading colonies (SC or NSC types) of the bacterial species Moraxella nonliquefaciens, M. bovis and M. kingii were found to differ very distinctly when used as recipients in streptomycin resistance transformation. N type isolates of these species were always found to be deficient in competence, being either non‐transformable or weakly responding when exposed to autologous or homologous DNA extracted from streptomycin resistant mutants of N cells. Corresponding SC or NSC type isolates revealed much higher T/E (transformants/colony‐forming recipient units) ratios when exposed to the same N type DNA preparations (T/E = 10 ‐3 to 10 ‐2 or above in 11 strains, 10 ‐4 to 10 ‐5 in three strains; short‐term (20 min) DNA exposure). These values are from about 400 times to more than 10 6 times higher than the N type T/E ratios in individual strains. In the three strains with low SC or NSC T/E ratios, the corresponding N forms were either transformable by long‐term DNA exposure only or completely non‐transformable by any method. By using a modification of the long‐term DNA exposure technique for screening of competence on more than 14,000 single colonies, no spontaneous change of competence independent of variation in colony type and fimbriation could be detected in any direction, except for one single observation of genetically stable change from low‐level competence to incompetence in an N type variant. It is briefly discussed whether fimbriae could play a hitherto unknown active role as an important competence factor, or whether the cellular appendages may be functionally inert in this respect, only reflecting the presence of one or more such factor(s).