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Volume 46, Issue 1
Displaying 1-7 of 7 articles from this issue
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TORU ENDO1971 Volume 46 Issue 1 Pages 1-5
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe occurrence of three dimeric peroxidase isozymes specified by alleles Pe2A and Pe4A was confirmed from observation of a cross between two strains of Oryza perennis. The intensity ratio of the three isozyme bands, 2A, 3A and 4A, deviated from the expected distribution pattern in lemmas and paleas of the F1 plants and most of the F2 heterozygous segregants. Among 25 F2 heterozygotes, only one showed the expected distribution pattern. Both types of distribution pattern may be explained by differential allelic activities due to allele-specific inducing systems, though other factors may be involved.View full abstractDownload PDF (834K) -
TARO ITOH, KENJI MORISHITA1971 Volume 46 Issue 1 Pages 7-15
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe genetic feature of protoperithecium formation and the cause of its persistent variation in Neurospora crassa were investigated.
In the F1 progenies from reciprocal crossings between strains showing different ability of protoperithcium formation, most segregants showed the ability similar to the maternal parent.
The ability to form protoperithecia of a culture was generally transmitted to isolates obtained from single conidium, hyphal tip or hyphal segment. However, significant variations in the ability were observed depending on the kinds of cells isolated.
The ability of protoperithecium formation decreased during succesive transfers, and it was lost after several transfers.
The protoperithecium formation in the culture of heteroplasmic hyphae obtained by making anastomosis between two strains was more vigorous than either one of the parental strains.
From these results it was considered that a cytoplasmic factor is responsible for the protoperithecium formation, and the variation in the ability of protoperithecium formation among cultures from every sexual, asexual spores and hyphal segments may not only result from an irregular distribution of the cytoplasmic factors but also come from physiological abnormalities accompanied by cellular differentiation and aging, and regenerated by cellular meeting with other cytoplasm or nucleus.View full abstractDownload PDF (921K) -
MITSUO TSUJITA, SUSUMU SAKURAI1971 Volume 46 Issue 1 Pages 17-31
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe albino gene (al) is a simple recessive gene. Embryos homozygous for al develop normally to young larvae which are able to hatch out by chewing up the egg chorion and grow normally during the 1st instar. Their lethality appears immediately after the 1st molting.
The phenotype of lethal albino larvae resembles that of lethal lemon larvae. Neither can chew up mulberry leaves owing to insufficient sclerotization of the hypodermal cuticle.
Abnormal pteridine metabolism was found in the lethal albino larvae. It is assumed that a step of sepiapterin formation is blocked in their main pteridine metabolic activities.
It was found that al/al larval extracts have a lower activity of phenol oxidase than. +al/+al larval extracts.
It was suggested that al/al larval extracts have also a lower activity of phenylalaine hydroxylation than +al/+al larval extracts.
It seems that in the lethal albino larvae abnormal pteridine metabolism has some close relation to a defective phenylalanine metabolism.
Maternal effects of +al gene may explain why young al/al larvae do not show their lethal phenotype inside the eggs.View full abstractDownload PDF (1845K) -
MICHIHARU SEGAWA, SEKIKO KISHI, SEIZI TATUNO1971 Volume 46 Issue 1 Pages 33-39
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn both the female and male plants of Cycas revoluta, somatic chromosome was 2n=22, that is from 1st to 11th pair. The pairs from 1st to 10th were indistinguishable between the two sexes. In the female plant the chromosomes of the 11th pair were homomorphic, both being long and J-shaped. However, in the male plant the chromosomes of the 11th pair were heteromorphic; one is long and J-shaped, the other short and V-shaped. And this J-shaped one was indistinguishable from J-shaped ones of the 11th pair of the female plant. Therefore, the chromosomes of the 11th pair of both sexes are assumed to be the sex chromosomes; _??_ 2n=20+XX and _??_ 2n=20+XY.View full abstractDownload PDF (2764K) -
SYNERGISTIC INTERACTION BETWEEN SECOND AND THIRD CHROMOSOMES ON VIABILITY OF DROSOPHILA MELANOGASTERKAZUHIKO KOSUDA1971 Volume 46 Issue 1 Pages 41-52
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSHomozygous viability effects of 289 pairs of second and third chromosomes simultaneously extracted from a natural population were measured, separately and jointly. Frequencies of lethal second and third chromosomes were 15.9% and 26.7%, respectively. Random association between chromosome pairs was confirmed. Total homozygous load on two major autosomes was calculated to be 0.791 lethal equivalents per gamete. This total load was partitioned into loads of 0.481, 0.232, and 0.078 due to lethals, mild detrimentals, and severe detrimentals, respectively. The D/L ratio for second and third chromosomes are 0.681 and 0.674. The results indicate that there exists about 7% interchromosomal synergistic interaction between mildly deleterious genes on the two chromosomes, and an interchromosomal epistasis of 10% towards the positive direction was also measured in the artificially combined pairs of two major autosomes. It is remarkable that two cases of “interchromosomal synthetic lethals” were found out of 101, and only in the artificially combined pairs of chromosomes in which variance in the magnitude of interaction was significantly larger than that in natural pairs of chromosomes.View full abstractDownload PDF (1128K) -
SUMIKO NAKAI1971 Volume 46 Issue 1 Pages 53-60
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe pupal sheaths of a wild type strain of the housefly, Musca domestics L., contained a large amount of β-alanine, while those of bp (black-puparium) mutant contained less than one tenth of amount found in the wild type.
In this paper, the metabolism of β-alanine in the housefly was studied by injecting various radioisotopic compounds into early pupae of a wild type and bp mutant strains and tracing the radioactivities.
In puparium of the wild type strain, the content of β-alanine increased in parallel with the pupal coloration. This β-alanine was probably derived mainly from aspartic acid. The conclusion came from the experimental facts that when C14-aspartic acid was injected into early pupae of the wild type strain, as much as twenty percent of it was converted into C14-β-alanine within one hour, although no such conversion was observed when the same injection experiment was done for bp pupae.
On the other hand, uracil, orotic acid and carbamylaspartic acid were found to be precursors of β-alanine in both the wild type and bp mutant pupae. The percent conversion of these compounds into β-alanine was equal in both the strains. The small amount of β-alanine detected in pupal sheaths of bp mutant might come from the degradation of these compounds.
Between the two strains studied, no remarkable difference was observed in the degradation of β-alanine or incorporation of it into pupal sheaths.
Thus, the difference in β-alanine content in pupal sheaths between the wild type and bp mutant strains is probably due to the difference in biosynthesis of β-alanine between the strains. The bp of the housefly is a mutant which lacks the biosynthetic pathway to β-alanine from aspartic acid, and the presence of a larger amount of β-alanine in the wild type strain during the puparium formation may affect a series of reactions leading to puparium coloration.View full abstractDownload PDF (767K) -
ISAMU HAYATA, SHIN-ICHI SONTA, MASAHIRO ITOH, NORIO KONDO1971 Volume 46 Issue 1 Pages 61-64
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (1226K)
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