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Biomedical subjects

T Iino

Publications and source records attributed to T Iino.

At least 163 records · Page 9Linked to original sources

The role of cAMP in flagellation of Salmonella typhimurium.

A mutational alteration either in adenylate cyclase (cya-) or in cyclic-3'5'-AMP (cAMP) receptor protein (crp-) rendered Salmonella typhimurium incapable of producing flagella. The amount of mRNA specific for flagellin in these mutants was almost negligible when assayed in an in vitro protein synthesizing system. A secondary mutation cfs, partially suppressing the cya- mutation, was identified among the revertants of cya-. A mutation in the same cistron as cfs resulted in a non-flagellate phenotype either by itself or in combination with cfs. The cistron, which was given the gene symbol flaT, was located between flaE and flaL. It was suggested that cAMP receptor protein together with cAMP modulates the gene flaT, which in turn acts as a positive effector on the synthesis of active mRNA specific for flagellin.

Adenylyl Cyclases↗

Phototactic response of aerobically cultivated Rhodospirillum rubrum.

Motile cells of aerobically cultivated Rhodospirillum rubrum, containing no detectable bacteriochlorophyll, assembled at a spot of strong light projected through a dark-field condenser. Far-red light was not effective, indicating that bacteriochlorophyll and thus photosynthetic metabolism was not responsible for the phenomenon. Bacteria moving towards the centre of the light spot changed direction less frequently than those moving towards the margin. They also responded to temporal changes in the intensity of light, altering their swimming direction more frequently after a sudden decrease in light intensity than after an abrupt increase.

Aerobiosis↗

Temporary expression of flagellar phase-1 in phase-2 clones of diphasic Salmonella.

Diphasic Salmonella strains, Salmonella typhimurium TM2, S. abony SW803 and their derivatives differing in flagellar shape and antigen type, were found to produce copolymer segments of phase-1 and phase-2 flagellins among flagella in phase 2, except for a strain which is non-flagellate in phase 1. The copolymer segments were not detected in phase-1 clones of any of the strains. The wave-forms of the copolymers are homologous with those of the copolymer filaments obtained by in vitro reconstitution of the corresponding phase-1 and phase-2 flagellins. Thus, in the mutant producing normal flagella in phase 1 and straight ones in phase 2, copolymer segments with curly or small waves appear among the straight filaments. Formation of the copolymers was attributed to temporary derepression of the structural gene for phase-1, flagellin, HI, in phase 2. Copolymerization occurred in a fraction of the phase-2 cell population at late exponential and early stationary phase in nutrient broth cultures. When a phase-2 cell was temporarily derepressed, the copolymers formed almost simultaneously in every growing flagellar filament of the cell. Their formation continued for a short period until the supply of phase-1 flagellin was exhausted after re-establishment of repression. This period was estimated to be 7-7 min on average, fluctuating between 4 and 13 min in a cell population of a straight flagellar mutant whose generation time was 55 min in late exponential phase.

Bacterial Proteins↗

Serological study of bacterial flagellar hooks.

Bacterial hooks were partially purified from flagella isolated from Salmonella SJ25, by treatment with heat to depolymerize flagellar filaments and with n-butanol and calcium chloride to remove membranes. Antihook serum was obtained from a rabbit inoculated with a preparation of hooks. The serum contained antibodies directed against the flagellar filament and cell membrane. These antibodies could be removed from the serum by absorption with purified flagellar filaments and cells of a nonflagellated mutant strain. It was shown by electron microscopy that anti-SJ25-hook antibody reacts with hooks from a number of strains of Salmonella which differed from SJ25 in H and O antigens, flagellar shape, and motility. Hooks possessed by various strains of Salmonella have a common antigenicity. In addition, anti-SJ25-hook cross-reacted with hooks from Escherichia coli W3110 but did not react at all which those from strains of Serratia, Proteus, Aerobacter, and Klebsiella. It is well known that bacteria stop moving upon addition of antiflagella serum to the medium. However, the addition of purified antihook was found to have little effect on motility. At physiological ionic strength and pH, flagellin (Salmonella) can polymerize into flagellar filaments only in the presence of seeds. It was shown that a crude preparation of hooks was able to initiate in vitro polymerization of flagellin.

Animals↗