Mutants of a Bacteriophage of Bacillus Megatherium

Murphy, James S.

doi:10.1084/jem.96.6.581

Cited by 7 publications

(6 citation statements)

References 5 publications

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“…In a previous report, the recombination phenomenon was shown to occur in the plaque mutant phages of B. ~g a l ~i u m 899a (1). The present study is an amplification of thl.g work.…”

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confidence: 57%

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Recombinations of Mutant Phages of Bacillus Megatherium 899a

Murphy

1953

Journal of Experimental Medicine

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In a previous report, the recombination phenomenon was shown to occur in the plaque mutant phages of B. ~g a l~i u m 899a (1). The present study is an amplification of thl.g work. Data are included on the percentages of recombination of the mutants isolated to date, and on the results of an analysis of these percentages. The B. megatherium system is unique in that all the mutants studied and most of the recombinants found can be readily recognized without recourse to special techniques. It is possible, in at least one case, to recognize plaques of phages with three mutations since each mutant produces its own characteristic effect on the plaque morphology.Phage recombination has been extensively studied by Hershey and coworkers (2-5) who have shown that the patterns of recombination of T2 coliphage mutants are essentially the same as those patterns found in the genetics of higher animals and are apparently genetic in nature. A further refinement of the work has been made by Doermann and Hill (6) using coliphage T4, a virus closely related to T2. Their findings were used to test a theory advanced by Visconti and Delbriick (7) which indicates that the coliphage T2 recombination can be explained on exactly the same basis as gene recombination in higher animals, with the major hypothesis that several rounds of mating occur during each infectious cycle. Doermann and Hill's results were in close agreement with those predicted by the hypothesis for five rounds of mating.Burner (8) and Hirst and Gotlieb (14) have been able to demonstrate recombination with influenza virus and Burner has suggested the possibility that the phenomenon, if it occurs naturally, might play a role in the sudden changes in virulence that are found. Magerials and MethodsPhage from B. megaIherium 899a (lysogenic) was used throughout all the studies, using methods previously reported (1, 9). The recombination experiments were done in a highly standardized way. The two phages under study were added simultaneously to a tube con-

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“…In a previous report, the recombination phenomenon was shown to occur in the plaque mutant phages of B. ~g a l ~i u m 899a (1). The present study is an amplification of thl.g work.…”

supporting

confidence: 57%

“…Phage from B. megaIherium 899a (lysogenic) was used throughout all the studies, using methods previously reported (1,9). The recombination experiments were done in a highly standardized way.…”

Section: Magerials and Methodsmentioning

confidence: 99%

Recombinations of Mutant Phages of Bacillus Megatherium 899a

Murphy

1953

Journal of Experimental Medicine

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“…Table III gives a description of the various mutants found and illustrates them. Mutants already described have been starred (3,4). It will be seen that no radically different types have been found except u which is very turbid.…”

Section: O A~papaginementioning

confidence: 70%

“…However, the task of completely differentiating these phages is beyond the scope of this project. In spite of these diflicul- (3,4) and are included here merely for comparative purposes. N •ffi normal size.…”

Section: O A~papaginementioning

confidence: 99%

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Some Mutant Phages Produced Directly by Bacillus Megatherium 899a With Their Rate of Occurrence

Murphy

1954

Journal of Experimental Medicine

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The purpose of this study is to find out if bacteriophage mutants are produced directly by the lysogenic bacterial strain Bacillus megatherium 899a (1) and, if so, what types and frequencies are to be found. The results indicate that in all probability phage mutants are produced directly from lysogenic B. megatkeriura 899a and occur with a frequency of about one recognizable plaque mutant per 2000 normal individuals.The experiment was designed to show whether passage through a sensitive cell was a major factor in the apparent production of mutants. The possibility of passage through a sensitive cell in the lysogenic culture was controlled by contrasting B. megatherium 899a growing in two media, one in which infection was virtually certain (peptone) and one in which it was highly unlikely (asparagine) (2). If the number of mutants was approximately the same in the two cultures, it would show that the infection of a sensitive cell occurring in the lysogenic culture did not play an important role in the production of mutants. If there was a significant variation in the two cultures and it could be demonstrated that the two mutation rates were not correlated, the plating suspension could be ruled out in the occurrence of mutants.The results indicate that sensitive cells in the lysogenic culture do not play a significant role. The plating suspension test did not reveal as clear cut a result but gives every reason to believe that mutants are produced directly by B. megatherium 899a (lysogenic).An attempt has been made to isolate and classify all the mutant phages recognized during this study and data are included which give some indication of the frequency of occurrence of these mutants. Several new mutants have been found, increasing the number described to 19 (3, 4). Materials and MethodsBacterial strains.--B, megatherium 899a (lysogenic) isolated by den Dooren de Jong (1) was sent to this laboratory by" Gratia in 1949. It has been transferred weekly on 2 per cent 657

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Génétique des Bactériophages

Fredericq

1958

Handbuch Der Virusforschung

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Mutants of a Bacteriophage of Bacillus Megatherium

Cited by 7 publications

References 5 publications

Recombinations of Mutant Phages of Bacillus Megatherium 899a

Recombinations of Mutant Phages of Bacillus Megatherium 899a

Some Mutant Phages Produced Directly by Bacillus Megatherium 899a With Their Rate of Occurrence

Génétique des Bactériophages

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