A simple method for the measurement of the behavioral responses of Drosophilamelanogaster to the various sugars and a method for recording nerve responses from a single chemosensory hair were described and the results were analyzed. The fly showed preference for maltose, sucrose, glucose, fructose, xylose, lactose, mannose and galactose, especially for the former four sugars, in the preference-aversion test between sugar and water. Electrophysiological responses from a labellar hair by stimulation of those sugars showed that the labellar hair examined was sensitive to maltose, sucrose, glucose and fructose, giving a series of spikes different from those initiated by NaCl and water. The magnitude of nerve responses to these four sugars was arranged in the order of the maximal number of impulses from high to low as follows: maltose, sucrose, glucose and fructose. The labellar hair examined was insensitive to xylose, lactose, mannose and galactose.
The genetic determinant of O-3 of Salmonella senftenberg (O-1, 3, 19) is considered to be sitiuated at O locus near his on the chromosome and that of O-1, 19 close to pro. The prophage attachment site of ε34 is assumed to be located in the region of leu- pro-nic on the chromosome.
An experiment was conducted to find the relation between dispersive behavior and fitness using six strains of D. melanogaster. The dispersive behavior of a strain is quite different in the pure and the mixed condition. Both accelerations and diminutions of dispersive activity were detected. The activity of se strain was stimulated by other strains used, while cn bw strain reduced its activity except in the case of mixture with wa. The dispersive activity is negatively correlated with fitness so that the usual conjecture that less fit flies may be those “forced” to migrate seems to hold.
For callus induction and restoration of plants from callus tissue of buckwheat, kinetin showed no effect, but supplements of 2, 4-D (10mg/l) to White's basal medium induced calluses from germinating seeds. Callus tissues subcultured for 48 months grew vigorously on the modified White's basal medium. Nearly 40.5% of cells of callus tissues which were subcultured 6-36 months had the diploid chromosome number 16. The cell population became much more uniform in chromosome number after a longer period of subculture. Shoot and root formation were not found on the proliferating calluses in White's basal medium and modified white's basal medium. However, transfer to modified RM-1964 medium after one or two months resulted in a tendency towards organ-forming capacity. The five restored plants obtained showed normal chromosome constitution.
The chromosomes of 22 Japanese weevils were studied in the male germ line using modern squash preparations. The results are summarized in Table 1. Nineteen species have an Xyp sex-determining mechanism, but three lacked first metaphases, so that the mode of association of the X and y is uncertain.
1. The natural populations of D. immigyans were sampled at various places on three main islands of Hawaii and the inversion polymorphism examined in 1532 “egg samples” and 103 “male samples”. The samples at different places on each island were from dissimilar habitats. 2. Three inversions of Chromosomes II were widespread throughout the islands and always present in all the populations studied (except for a few inadequately sampled populations). 3. Within each island there is a general similarity from population to population in the relative frequencies of these inversions and in the amount of inversions per individual. 4. Nonetheless, signficant differences in some inversion frequencies occurred between certain localities with dissimilar environmental conditions. 5. There were consistent results to indicate that the relative frequencies of the inversions remained fairly stable throughout the considerable periods of time in every population sampled more than twice. The general stability is considered to be maintained by selective differences on chromosomal types. 6. The relative distribution of the inversions were distinct from one island to another; the differences among islands are considered to be racial differences. 7. We are inclined to suggest that the differences shown in (4) and (6) are mostly due to adaptive response, perfected by natural selection, to differences in environmental conditions. 8. The magnitude of inversions per individual observed in the Hawaiian population of D. immigrans show a much higher range compared to that reported by other workers for continental areas. 9. One paracentric and one pericentric inversions were detected in the Hawaii populations, each at different local; they are probably endemic to the island.