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Volume 43, Issue 1
Displaying 1-10 of 10 articles from this issue
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C. AUERBACH, D. RAMSAY1968 Volume 43 Issue 1 Pages 1-8
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn a doubly auxotrophic strain of Neurospora, diepoxybutane produces many adenine-reversions and very few inositol-reversions. This does not appear to be due to selective elimination of potential inositol-reversions by inositol-less death. The selectivity of diepoxybutane in this system could be strikingly reduced when treatment was given to a growing culture instead of in vitro to conidia. Possible reasons for this are discussed. Whatever the interpretation of these data, they argue against explaining this case of mutagen specificity solely by the specificity of chemical reactions between mutagen and DNA.View full abstractDownload PDF (964K) -
T. IMAIZUMI1968 Volume 43 Issue 1 Pages 9-14
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe estimation of recombination frequencies by the method of maximum likelihood was investigated on backcrosses when one character is partially manifested. The estimation was performed for tri-coupling backcrosses with some discussions about their consistent simultaneous estimates.View full abstractDownload PDF (422K) -
K. WAKE, H. OCHIAI, S. TANIFUJI1968 Volume 43 Issue 1 Pages 15-26
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSBiochemical analyses with DNA and histones extracted from ovules of cold treated Trillium and of the control were undertaken.
When the DNA fraction of cold treated plants was treated with sequential RNase-trypsin-chloroform procedure after SDS-phenol extraction, supplemental minor peaks in MAK-column chromatographical profile were detected.
Histones extracted from cold treated plants were different from those of the control in a high ratio of p-histone/s-histone and in the relative ratios of the fractions separated by CMC-column chromatography.
A possible relationship between differential staining of heterochromatin in the mitotic chromosomes and these biochemical phenomena was discussed.View full abstractDownload PDF (1299K) -
P.G. KALE1968 Volume 43 Issue 1 Pages 27-31
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSSpontaneous crossover values from males of D. ananassae showed great individual variation. From such a variable population two-way selection was started selecting randomly twenty heterozygous males from testcross progeny of a male with highest crossing over and from one with lowest values. Similar selection was continued for 15 generations. Wide variations in generation means were observed. The high line exceeds the low line significantly in mean crossover frequency. The difference in the two lines was established although the progressive increase was not significant. Since the difference in the two lines was established the effect of selection is genetic.View full abstractDownload PDF (525K) -
HIDETOSHI KISHIKAWA1968 Volume 43 Issue 1 Pages 33-42
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe cytological behavior of accessory chromosomes in the plants with seven and eight accessories was investigated in meiosis. The results are summarized as follows:
1. Notwithstanding the fact that both of the plants have a large number of accessory chromosomes, the accessory chromosomes pair very well with each other and form many radial multivalents. In the radial multivalent of even valency two types were distinguished; that is, the one is symmertical and the other asymmetrical. The mode of configurations in the 7acc. plant was 1IV++1II+1I followed by 3II+1I; and in the 8acc. plant 1IV+2II followed by 1VIII.
2. The disjunction of accessory chromosomes at anaphase I was not unusual, being determined by the type of metaphase I configuration. That is, in most of cells 3-4 and 5-2 distributions were observed in the 7acc. plant; and 4-4 and 5-3 in the 8acc. plant. The cells with one or two laggards of accessory chromosomes were considerably observed, but the number of micronuclei in tetrads was a very few. This indicates that the meiotic elimination of accessory chromosomes is suprisingly low.
3. The cytological behavior in different species with many accessory chromosomes and the numerical limit of accessory chromosomes contained per plant were dicussed.View full abstractDownload PDF (2249K) -
TEIJI IIJIMA, YUTAKA SAKAMOTO1968 Volume 43 Issue 1 Pages 43-48
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDefective phages φ170dg recombined with the related phages λ, 434, 82 or φ80 when one of the related phages is superinfected to a defective lysogenic strain φ170dg, or when a doubly lysogenic strain (φ170dg)(φ) was induced with UV irradiation. The resulted particles having the immune specificity of φ170 always have the host range of the colysogenizing phage, that is, φ170hy type.
When a defective lysogenic strain was spotted on a hetero-immune indicator, the recombinant type phage is responsible to form a lytic zone. The recombination was also confirmed by using various λsus mutants. In lysates prepared from doubly lysogenic strain (φ170dg)(λsus) contained both φ170hy and φ170hysus, or φ170hysus alone according to the sus markers used. From the recovery of the sus markers among φ170hy particles, we may assume the defective region of φ170dg.
Defective region of a given φ170dg was also assumed by complementation test, using Pm- (φ170dg) and various λsus mutants. From the results obtained by these methods, similarity of arrangement of genetic markers on the chromosome of λ and φ170 was assumed.View full abstractDownload PDF (666K) -
TOSIHIDE H. YOSIDA, HIROSHI OHARA, ROBERT A. ROOSA1968 Volume 43 Issue 1 Pages 49-56
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSChromosomes of sensitive and 5-fluorodeoxyuridine (FUDR) resistant sublines of mouse lymphocytic leukemia, P388, growing in vitro were observed. Chromosome number and karyotypes in the FUDR-resistant subline differed from those in the parental sensitive line both in the mode of total chromosome numbers (49 in the sensitive and 40 in the resistant sublines) and in the number of biarmed chromosomes (14 and 21, respectively). A sequential event of chromosomal damage, elimination and selection was considered as a cause of development of altered karyotypes in the FUDR-resistant subline.View full abstractDownload PDF (2124K) -
SADAO ICHIKAWA, ARNOLD H. SPARROW1968 Volume 43 Issue 1 Pages 57-63
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSInflorescences of Tradescantia virginiana L. HV Purple Dome (2n=24), heterozygous for flower color, were exposed to 100 to 500R of 137Cs gamma rays over a 16-hour period. Stamen hairs from both irradiated and unirradiated flowers were observed daily for 26 days after irradiation, and number and position of the somatic mutations (blue to pink) induced in the stamen hair cells were recorded.
Somatic mutations were induced at a rate of 4.75×10-4 mutant events per meristematic hair cell per R in the essentially single-meristematic-cell system. Using the mutant cells as markers it was estimated that the gamma rays evidently induced mitotic delay, lengthened cell cycle time and an impairment of normal reproductive integrity. The effect increased with increasing exposures.
The average daily increase in number of hair cells per terminal mutant event varied from 2.6 after 100R to 0.56 after 500R. The average mitotic cycle times estimated also varied from 17.5 hours after 100R to a maximum of 80 hours after 500R, an increase of approximately 4.6-fold in cycle time. However, the length of the mitotic cycle approached the control rate even after 500R after about 15 daysView full abstractDownload PDF (804K) -
KAZUO NAKATA, MASAO TANAKA1968 Volume 43 Issue 1 Pages 65-71
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSFlower buds varying in stages of development were harvested from tobacco plants (Nicotiana Tabacum). One of the five anthers from each flower bud was used to determine the stage of pollen development. According to this procedure all flower buds were classified into nine groups ranging from the stage of archesporial cells to that of mature pollen grains. The remaining anthers from each flower bud of every group were placed in a Erlenmeyer flask containing 40ml of solid tobacco C medium (Hildebrandt 1962) and then transferred to the modified RM-1964 medium (Linsmaier and Skoog 1965) containing 4mg/l of kinetin and 2mg/l of IAA. Fifteen days after the transfer, many embryoids appeared suddenly from the inside of dehisced anther which had been cultured from tetrad stage and these embryoids developed later into visible buds having dicotyledones. At the same time, callus was formed around the basal part of the buds. Forty five days later, numerous embryoids appeared from the proliferating callus. Chromosome counts conducted on a squashed preparation of the leaf primordia revealed that a young plant had 24 somatic chromosomes. This fact and that the embryoids appeared from the inside of dehisced anther and were easily removed from the wall suggest that they might be originated from developing germ cells. With regard to chromosome numbers of the plants, there are some possibilities that diploids or polyploids might appear from the proliferating callus.
Microscopic observation of cultured germ cells revealed their morphological changes into the following types: 1) Ellipsoidal, shrivelled pollen grains, 2) Germinated pollen, grains, 3) Hypertrophied pollen grains with transparent cell walls and abundant starch grains, 4) Pollen grians developing into yellowish, multicellular bodies which later give rise to embryoids.
It is very interesting that embryoids can be differentiated from germ cells at the tetrad stage.View full abstractDownload PDF (1371K) -
A REVIEW WITH ORIGINAL DATASAMUEL H. HORI1968 Volume 43 Issue 1 Pages 73-84
Published: 1968
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSStudies on multiple molecular forms (isoenzymes) of the glucose 6-phosphate dehydrogenase in animals including man so far published were reviewed.
Comparison was made among glucose 6-phosphate dehydrogenase isoenzymes from some rodents and man with regard to their electrophoretic mobility, intracellular location and sensitivity to inhibitors. It has been shown that the animals studied possess two major isoenzymes, fast and slow moving, and that they apparently differ in the intracellular location and sensitivity to inhibitors. The results suggest a possible functional differentiation between these two major isoenzymes.View full abstractDownload PDF (1655K)
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