ISSN:
1432-8798
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Following exposure of type 1 poliovirus (Mahoney and LSc 2ab strains) to guanidine hydrochloride, the presence of mutants resisting the action of the inhibitor could be demonstrated by means of the plaque method. Triple exposure to guanidine in increasing concentrations (70–150–250 μg/ml.) resulted in the isolation of highly resistant mutants, as compared to the parental strains, while a single exposure to 20–40 μg/ml. led to the demonstration of strains displaying an intermediate degree of resistance. Quantitative investigations of the resistance to 35 μg/ml. guanidine hydrochloride (i. e. to a concentration which still permits comparison with the parental strains) have shown the difference of susceptibility between the clonal strains obtained by the first method and the respective parental strains to be of the order of 106 in mutants of Mahoney virus and of the order of 105 in mutants of the LSc 2ab strain. The high degree of resistance of these mutants was further demonstrated by the fact that the maximum guanidine concentrations tolerated by the host cells (175–225 μg/ml.) still allowed the above mentioned clonal strains to display a plaque forming capacity of 10−1.2–10−4 as compared to that of the initial population, whereas similar resistance rates were displayed by the parental population only at concentrations as low as 10–25 μg/ml. Theg − character (guanidine resistance) proved to be stable in the course of 10 passages in the absence of the inhibitor, and the virus reconstituted from the infectious RNA extracted fromg − mutants maintained this character. A study of the correlation between guanidine resistance on the one hand, and the markersrct 40°, MS, E, as well as neurovirulence in monkeys, on the other, has shown that the presence of theg − character is not associated with any change in these markers, as compared to their pattern in theg + parental strains. This shows that guanidine resistance is controlled by a distinct portion of the genetic material and does not display the phenomenon of covariation with neurovirulence.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01555095
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