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Kitahara, Haruo ; Watanabe, Akira ; Togawa, Kazuhiro
概要:
Synthetic routes are described a new protecting glucopyranoside. 1,2,3, 4-tetra-O(4-methoxyphenylmethyl) -a-D-glucopyranoside. This compound was synthesized via sixsteps and may be interesting as a building block for the
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synthesis of Oligosaccharides.
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| 2.
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Kitahara, Haruo ; Arai, Ken-ichiro
概要:
Two new copper reagents containg sulfur atom are described. Although there have been manyreports on the copper reagents.
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little is known on the disulfinyl copper reagents. In thiscommunication, we wish to report conjugate addition reactions of two new copper reagents toα,β-unsaturated carbonyl compounds.
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| 3.
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Masaki, Shinzo
概要:
Series of experiments have been carried out with eggs of the Emma field cricket (=Gryllulus mitratus in former publicati
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ons) in order to analyse the effects of temperature in early stages of development on the intensity of diapause, which supervenes at around the time the eggs absorb water. In the first series, batches of pre-diapause eggs were first exposed to different temperatures, respectively, and after the completion of water uptake each batch was further divided and transferred to temperatures of the second exposure for hatching. The results show that the higher the temperature in the first exposure, the longer was the hatching time at each temperature of the second exposure. When pre-diapause eggs had initially been kept at different temperatures and, soon after the onset of diapause, were subjected to cold exposure (6℃), the median effective duration of this treatment for the rupture of diapause was strikingly shorter in those eggs first kept at a low temperature (20℃) than in those kept at a high (30℃). From this it was concluded that the preliminary temperature treatment affects the intensity of diapause. In further experiments, eggs were first exposed to a high temperature for different periods, or for the same period (one week) in different stages, and kept at a low temperature in the remaining stages. From the record of their hatching time, it was suggested that the eggs were responsive to the diapause-intensifying action of high temperature in the late pre-diapause and early diapause stages.
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| 4.
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Masaki, Shinzo
概要:
A northern (Sapporo) and a southern (Koti) strain of the Emma field cricket (Teleogryllus sp.) were reared for three successive generations in the laboratory, and the characters responsible for the seasonal rhythm of their
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development were investigated. It was found that the embryonic diapause was obligate in both strains, but that the eggs of the northern strain were able to complete diapause at a lower temperature and also in a much shorter time than were those of the southern strain. The rate of post-diapause embryonic and nymphal development was again more rapid in the northern than in the southern strain. The northern adults tended to be smaller in body size than the southern ones, and this difference seemed to be related to their different rates of development. F 1 hybrids obtained by intercrossing of the second generation adults of the two strains were physiologically, as well as morphologically, intermediate between the parent strains, and it was suggested that the polygenes controlling the rate of nymphal development might be located in the autosomes and X-chromosome. From these results it is concluded that in the Emma field cricket the adaptation of the seasonal rhythm of development to local climatic conditions is genetically controlled. The implication of this variability was discussed to a certain extent.
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| 5.
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Masaki, Shinzo
概要:
Crickets are convenient systems for studying life-cycle evolution. They show a considerable diversity in life-cycle types, being homodynamic in some parts of the tropics and heterodynamic with various kinds of diapause and other
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regulatory responses in the temperate region. Crickets are relatively free from constraints by food supply, because they are omnivorous. Therefore, their geographical variation may clearly reflect climatic selection as exemplified by latitudinal dines in adult size, egg size and ovipositor length. These morphometric dines are closely related to development time, egg diapause and photoperiodic responses, indicating that crickets are highly variable within the framework of their species-specific patterns of life cycle. More fundamental variation is divergence in life-cycle pattern that may be associated with speciation, because closely related species are often different in their life-cycle patterns (e.g., homodynamic versus heterodynamic, or egg overwintering versus larval overwintering). Evolutionary flexibility of life-cycle traits may be assessed by studying cricket populations under special natural or artificial conditions. In Japan, a population of the nemobiine cricket (Dianemobius mikado) introduced from a temperate to a subtropical island has almost lost egg diapause presumably in the last 130 years. At volcanic geothermal spots in the northern island (Hokkaido), presumptive relict populations of the nemobiine species Dianemobius nigrofasciatus occur and sing in mid-winter, but this cricket retains the photoperiodic response of a southern bivoltine type. In the subtropical nemobiine D. fascipes, artificial selection has been effective in changing the incidence and depth of diapause, and strains comparable to the tropical and temperate forms were established. The responsiveness to photoperiod in wing-form determination was also remarkably changed by selection, but this change was not associated with a change in critical photoperiod. Alternated selection in the opposite directions at photoperiods above and below the critical value to be selected was necessary to shift the critical photoperiod.
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| 6.
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Masaki, Shinzo
概要:
The ground cricket, tentatively identified as Pteronemobius tapro-banensis WALKER, regulates its egg diapause, growth ra
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te, and wing form in response to photoperiod. These responses seem to be physiologically independent of one another, for each of them shows not only a photoperiodic curve, but also a geographic pattern, of its own. Geographic variations in diapause and development indicate at least three different life cycles. (i) A univoltine cycle with eggoverwintering would be prevalent to the north of about 35°N, because the egg enters diapause even in long days (>14 hr), and the nymph controls its growth by a response of short-day type. (ii) A multivoltine cycle with egg-overwintering would be common between 28 and 35°N, because the egg averts diapause in long days, and the long-day retardation of nymphal growth is somewhat reduced. (iii) A multivoltine cycle with nymphal overwintering would occur to the south of about 28°N, because the egg diapause is virtually absent and the nymphal growth is retarded in short days (<14 hr). The last type probably represents a distinct species.
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| 7.
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Masaki, Shinzo
概要:
To stimulate further study on seasonal adaptations in insects, two hypotheses are proposed, one accounting for latitudinal variations in diapause intensity and the other pertaining to the phenotypic plasticity of critical photoperiod
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for diapause induction. (1) In some species with constant voltinism, diapause intensity increases southward to cope with higher risks of untimely termination of diapause before winter. In other species with variable voltinism, it decreases southward presumably because of stronger selection for nondiapause phenotypes and positive correlations between diapause intensity and incidence. (2) Clinal variations of critical photoperiod for diapause induction may be mimicked by phenotypic responses to temperature. Such plasticity expands the latitudinal range of adaptation. In a noctuid moth, the critical photoperiod is increased by long photoperiods in the early stage of development, so that photoperiod itself may also be involved in phenotypic adaptation to climatic gradients.
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| 8.
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Masaki, Shinzo
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Masaki, Shinzo
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| 10.
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Masaki, Shinzo
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