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D T Suzuki

Publications and source records attributed to D T Suzuki.

At least 37 records · Page 2Linked to original sources
PubMed1971

Temperature-sensitive mutations in Drosophila melanogaster. VII. A mutation (para-ts) causing reversible adult paralysis.

A temperature-sensitive mutation, para(ts), in Drosophila melanogaster causes an immediate, but reversible, paralysis of adult flies when they are shifted from 22 degrees C to 29 degrees C. The mutation is a sex-linked recessive that maps 2.8 units to the left of f. Wild-type flies observed for 2-hr periods exhibited normal mobility at all temperatures between 22 degrees C and 35 degrees C. From 22 degrees C to 25 degrees C, para(ts) flies were wild type in walking, climbing, and flying ability. At 1-degree intervals above 25 degrees C, para(ts) flies became increasingly debilitated; at 29 degrees C, complete paralysis occurred. After flies were maintained for prolonged intervals at 29 degrees C, some activity could be recovered at that temperature. Studies of the behavior of mosaics at 29 degrees C revealed a requirement of the (+) allele in the head for mobility, and a thoracic component for proper leg movement. Normal electroretinograms were obtained at both 22 degrees C and 30 degrees C. The results suggest a temperature-sensitive defect in the nervous system.

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PubMed1971

Temperature-sensitive mutations in Drosophila melanogaster. 8. The homeotic mutant, ss a40a .

There exists in Drosophila a class of mutations called "homeotic" that cause changes in determination of the imaginal discs. The homeotic mutant, ss(a40a), was found to have a temperature-sensitive transformation of the arista segment of the antennal complex to a tarsus of the leg. In a selected stock penetrance was complete, so that at 29 degrees C normal aristae were produced, whereas at 17 degrees C complete tarsi developed in all flies. "Temperature-shift" studies revealed a temperature-sensitive period in the third larval instar. The temperature-initiated action of ss(a40a) does not appear to result from a simple wave or gradient of determination passing through the disc. Shifts up during the temperature-sensitive period yielded leg tissue proximally, which increased distally with progressively later shifts. Shifts down yielded leg tissue at the aristal base, which retreated with later shifts.

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PubMed1970

Temperature-sensitive mutations in Drosophila melanogaster. IV. A mutation affecting eye facet arrangement in a polarized manner.

Drosophila melanogaster females heterozygous for the mutation N(60g11) have wild type eyes when raised at 29 degrees C but a disrupted arrangement of facets and extra bristles at 21 degrees C. Shifts of cultures from one temperature to the other at different stages in development revealed that facet arrangement is altered by temperature during the third larval instar. The facet pattern is affected in a vertical wave that proceeds anteriorly from the posterior rim of the eye. The role of the Notch locus in development is briefly discussed.

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PubMed1970

Temperature-sensitive mutations in Drosophila melanogaster. V. A mutation affecting concentrations of pteridines.

A temperature-sensitive ras allele has an effective lethal phase at 29 degrees C about 12 hr after pupation and a temperature-sensitive period for lethality beginning midway through the third larval instar and ending around pupation. The mutation also alters the quantity of pteridines present in the eyes, testes, and Malpighian tubules at 29 degrees C. The temperature-sensitive period for pigment production in the Malpighian tubules occurs in the egg and first instar larvae, and in eyes and testes after pupation. The demonstrated autonomy of the mutant in the eyes implies the tissue-specific functioning of the gene. We suggest that the different temperature-sensitive periods for a single mutation indicate tissue-specific activation of a gene at different times during development, although the possibility of activation of preformed polypeptides has not been eliminated.

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PubMed1969

Temperature-sensitive mutations in Drosophila melanogaster. 3. Dominant lethals and semilethals on chromosome 2.

Dominant temperature-sensitive lethal and semilethal (DTS-L) mutations induced by ethyl methanesulfonate have been recovered in chromosome 2 of Drosophila melanogaster. The 19 (0.39% of the chromosomes screened) characterized had greater than 65 per cent viability at 22 degrees +/- 2 degrees C and less than 5 per cent at 29 degrees +/- 0.5 degrees C. Fifteen of the DTS-L's map genetically as point mutants, one appears to be a synthetic lethal, and the remaining three yielded sterile females. Ten different DTS mutants had a high survival in triploid females at 29 degrees C. Eleven DTS-L's were found to map in the same genetic region (dp-b). All behaved as recessive lethals at 22 degrees C and failed to survive at 22 degrees C when combined with mutants 3 and 12. Crosses of the 11 mutants in all possible pairwise combinations yielded a circular complementation map with a side branch. The effective lethal phases and temperature-sensitive periods during development were determined for 15 of the mutants.

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