1. The eye-antennal discs from the mature third-instar larvae (95 hours old after hatching at 25°C) of D. melanogaster were cultured in vitro in a synthetic medium, to investigate some effects of the cephalic complexes cultured together. 2. In comparison with culturing the eye-antennal discs alone, the culture of the eye-antennal discs together with the cephalic complexes showed more pronounced growth and differentiation of the eye discs. 3. The cephalic complexes of Oregon larvae were found to have effects of promoting growth and differentiation of the Oregon strain upon the eye discs of Bar larvae as well as those of Oregon larvae. 4. The cephalic complexes of Bar larvae showed to have effects performing the development of the Bar strain upon the eye discs of Oregon larvae as well as those of Bar larvae. 5. Those facts suggest that the genie action appears first on the brain and the“ring gland”in the cephalic complex, which then influence the growth and differentiation of the eye disc.
At MI in F1tabacum×alata, 1-6 bivalents were observed, and the most frequent configurations found were 3II+17I, and 4II+15I, although rarely trivalents occurred. According to Kostoff's description (1943), the hybrids, tabacum×alata and tabacum×Sanderae contained 5-9 bivalents and also some polyvalents. The writer (1953) reported that F1tabacum×sylvestris had 0-9 trivalents with mode 3. In F1tomentosa×sylvestris, Goodspeed (1934) counted 0-7 bivalents with mode 2-3, and Kostoff (1943) found a similar meiotic pairing behaviour. In F1tomentosiformis×sylvestris, closely related to the former, Kostoff (1943) observed somewhat fewer bivalents. The writer also observed that three hybrids sylvestris×tomentosiformis, sylvestris×tomentosa and sylvestris×otophora had each 1-9, 0-9 and 0-5 bivalents with each mode 4, 3 and 2 in the above cited order. These facts suggest that there are 2-4 pairs of homologous or partially homologous chromosomes between tomentosa group and sylvestris genomes. Accordingly, the bivalents found in F1tabacum×alata cannot be attributed simply to homologous relation between two subgenomes of N. tabacum and alata genome. At MI in F1tabacum×tomentosiformis, most frequent configuration found was 12II+12I and the next, 11II+1III+11I. Besides these configurations, a few deviations from them were found. This meiotic behaviour agrees with Goodspeed's findings (1934) in the same hybrid. Since the studies on F1tabacum×tomentosa by Goodspeed and Clausen (1928), N. tomentosa or N. tomentosiformis is recognized by many investigators to be one of the ancestors of N. tabacum.
The relation between genome constitution and flavonoid ingredients was investigated in Triticum and its related genera with the aid of two-dimensional paper chromatography. In all six genera were examined, namely Triticum (representatives of all 3 groups), Aegilops, Agropyrum, Haynaldia, rye and barley. The methanol extracts of fresh leaves were chromatographed. The solvents used were (1) organic phase of o-cresol-iso-propanol-water (5:1: 4) and (2) 10% acetic acid. Lead subacetate was found to be most effective as color reagent. All chromatograms were composed of yellowish and brownish spots; also a few spots of fluorescent substances were observed. The number of spots per chromatogram ranged from 7 to 13. Although identification of pigment spots was not carrid out, a certain relation was found between the pigment system and genome constitution of the examined materials. Within the genus Triticum, the pigment spots produced by one species seemed for the most part to correspond to those found in others, and to increase in number with the increasing number of genomes. Furthermore, spots produced by Agropyrum and Aegilops were partially similar to those of Triticum. Haynaldia and rye showed almost identical patterns of pigment spots, in particular with regard, to the two major pigments. However, they differed markedly from those of Triticum. Barley seemed to be quite different from all other examined genera.
This paper deals with the descriptions of the genic composition of the chinchilla rabbits and their offspring with black, dilute and white coats. In 132 litters with 808 offspring in total which were produced from the crossing of chinchilla rabbits, 694 chinchillas (85.9%), 44 dilute chinchillas (5.4%), 40 black (5.0%), and 30 white rabbits (3.7%) were produced. In reference to the gene symbols given for rabbit coat color by Castle (1930), the genic composition for the dilute, black and white rabbits are represented by the formulae, AA BB cchcch dd EE, aa BBcch cch DD EE, and ?? ?? cc ?? ??, respectively. In the crossing of the black rabbits there arised four individuals with black coats which are supposed to have the composition of aa cchcchDd. This suggests a possibility in producing the black rabbit laving aa cchcch DD, a pure black producer.
1) The relationship between phototaxis and tryptophan metabolism was investigated with a mutant “tan3” of D. melanogaster. 2) It has been found that “tan3” mutant flies, having little positive phototaxis, involve a little amounts of red and brown pigments in their eyes, as compared with those of wild type flies. 3) The amount of brown pigment in “tan3” mutant was increased by feeding the larvae with kynurenine or 3-hydroxykynurenine, and its positive phototaxis was simultaneously activated. These phenomena, however, have never been recognized by feeding the larvae with tryptophan. From these results, it was assumed that “tan3” might be a mutant having a very low metabolic activity between tryptophan and kynurenine. 4) The accumulation of cobalt was found in “tan3” eyes by feeding the larvae with kynurenine or 3-hydroxykynurenine, with an increase of brown pigment. This fact suggests that the cobalt-fuscanine named by Kikkawa and his coworkers may be produced in eye pigments and this metal containing pigment may take an important role in the activation of positive phototaxis.
The present paper describes the results of some observations on the behavior and mitotic cycle of tumor cells with lobated nuclei in the MTK-IV tumor. The MTK-IV tumor used here was induced by Tanaka and Kanô (Feb. 1954, unpublished) in the course of hepatoma-producing experiments through the application of azo-dyes in a Wistar rat. In the tumor samples taken during 53 to 102 transfer generations the frequency in occurrence of tumor cells with lobated nuclei of similar size was observed. Twenty to thirty percent of tumor cells was characterized by lobated nuclei. The daily observations of the frequency of cells with lobated nuclei showed that they increased during the early part of a transplant generation and decreased towards the latter part. Further, the mitotic rate of tumor cells with lobated nuclei is higher than that of regular mononucleate cells through the early part of a transplant generation. Morphological observations showed that different nuclear lobes of the same cell were synchronous in mitotic procedure, and that the prophasic changes proceeded normally in all of them. After the disappearance of the nuclear membrane, the metaphase plate was formed by the original chromosome grouping in different lobes. The metaphase was highly regular, and the anaphase also normal. The telophase proceeded regularly in its beginning. Later on during telophase, the swelling of telophase nuclei seemed to have influence on the formation of nuclear lobes The formation of lobated nuclei did not deal with the multipolar division at all. It is thus evident that the tumor cells with lobated nuclei of the MTK-IV do not represent degenerating cell types but are recognized as normally occurring stages in the mitotic cycle of tumor cells of this tumor.