High mutation rate of foot-and-mouth disease virus treated with hydroxylamine

Abstract

SummaryIt was found experimentally that 39% of the surviving plaque-forming units are mutants when the total infectivity of the treated sample is decreased by one neperian logarithm through inactivation with hydroxylamine.

Attenuation of foot-and-mouth disease virus by chemical means

“…At the latter time, a 103 reduction in surviving particles (PFU) was observed, with 70% chances to clone a mutant (2). It can be seen in Table 2 that the untreated clones (C1) have a lowAlogl0 which is reached 4 days after inoculation.…”

“…Two clones were isolated from plaques formed at time 0 hour and 2 clones from plaques obtained at time 1 hour after the beginning of the treatment. At the latter time, a 10 ~ reduction of surviving PFU had taken place, with over a 40% chance (2) to c]one a mutant out of the population. The clones obtained were tested for attenuation (Table 1) as well as for plaque size.…”

“…Since the character that one sets out to modifiy is in this case presumably complex, the expectation that one single mutagenic event will suffice to achieve it is slight. Former calculations (2), however, if applicable to attenuation, give a measure of the chance that one character linked to virulence might be modified during a mutagenic treatment. This chance is quite high.…”

“…The induction of mutations of viral hereditary characters by hydroxylamine is well established (1) and can be applied to foot-and-mouth disease virus (2). This mutagenic property has been however usually assessed only on viral biologic and chemical properties of a simple nature such as sensitivity to inhibitors (3), size of plaques (4), color of stained plaques (5), etc.…”