Shigella flexneri 2a and 3a, of which lactose infermentability is one of the important markers, were converted to lac⁺ and also to F'⁺ by transferring F-lac exogenote from Escherichia coli K12 F'⁺ strain. These F-lac Shigella have most of the properties characteristic for their parental S. flexneri except acquired characteristics of lactose fermentability and methylene blue resistance. All of the F-lac S. flexneri isolated were similar in antigenic structure to those of parental strains. They were insensitive to infection with male specific bacteriophage MS-2 of E. coli, but retained a sensivity to Shigella specific bacteriophage φS-123. A few trials for transfer of chromosome from male S. flexneri to F- E. coli were not successful, however transfer of F-genote was observed from male S. flexneri to female E. coli.

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The effect of atomic bomb radiation on antibody production was studied among persons living in 1961 who were exposed while in-utero to the atomic bomb in either Hiroshima or Nagasaki. They were inoculated with an Asian influenza virus vaccine. The relationship between the distance from the hypocenter at the time of the bombing and production of complement-fixing antibody to various types of influenza A virus was observed. The doctrine of original antigenic sin was applied to determine the effect. Patterns of the antibody levels in the group beyond 3, 000 m suggested that the virus of primary infection in the survivors was type Al. Significantly reduced Al type serum antibody levels were noted in both pre-and postvaccination sera of the subjects within 2, 000 m from hypocenter in Nagasaki.
The effect of a previous radiation exposure appeared much more clearly in heterotypic antibody response following Asian influenza vaccination, that is, the antibody responses to type Al viruses were almost completely suppressed in the subjects exposed within 1, 600 m in both cities despite the fact that the antibody responses to type A viruses were similar to those in the group beyond 3, 000 m. In contrast, homotypic antibody response to Asian type virus was rather enhanced in the subjects proximal exposed.

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In Tetrahymena pyriformis, the so-called “synchronous rounding” is shown when amino acids-starved cells are exposed to the cyclic temperature-treatment for synchronization. Although no division is seen in this system, the degree of synchrony, time sequence of the underlying change in “synchronous rounding” correspond exactly to those in synchronous division. In addition, the characteristic SH-changes preceding “synchronous rounding” are quite similar to those of synchronous division. Furthermore, the fact that only the supply of amino acids deflects “synchronous rounding” to synchronous division suggests a vital connection of the two systems. It can be concluded, therefore, that both systems have a common mechanism of phasing induced by the heat-treatment.
By scrutinizing “synchronous rounding” in reference to the prerequisites for synchronous division, the following are concluded. (1) The response of the oxidative phosphorylation system to the heat-treatment may be a leading cause of inducing synchrony, and the presumptive regulator enzyme (particularly thermo-labile) must be involved in this metabolic system. (2) Characteristic changes in SH amounts would also have a close connection with the mechanism of phasing. They, however, may depend on the action of the oxidative phosphorylation system. (3) Synthesis of the specific protein after the heat-treatment may not account for phasing itself, but it is sine qua non for synchronous division. (4) Synchronous division may occur only when protein synthesis is superimposed upon the active rhythm of the oxidative phosphorylation system and characteristic SH-changes which are phased by the heat-treatment.

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The larvae of Sarcophaga peregrina do not pupate in a wet condition. If they are placed in a glass vessel containing a certain amount of water, their pupation delays for 100 hr or more. The cause of this delayed pupation is neither a direct action of water to their integument nor disturbance of respiration, because the pupation takes place even in a wet vessel, if they have been previously exposed to a dry situation for a certain period.
The mature larvae transferred into a dry vessel from a wet one always pupate 18 to 24 hr later. Ligation experiments show that the hormone inducing the pupation is released 6 hr after transference to a dry condition. When the ligation is made in the middle of the animal, behind the brain and the ring gland, the hind part of it readily pupates by an injection of ecdysone. The results of these experiments suggest that retardation of ecdysone release is the final reason for the delayed pupation. It seems likely that their removal from water contact induces the secretion of ecdysone from the ring gland.

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