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1.
Comparative development of the narrow pinnules of rheophyticOsmunda lancea and of the broad pinnules of a related dryland species,O. japonica, was examined and the origin of rheophytic stenophylly was discussed. The mature leaves and their various parts ofO. lancea are smaller and narrower than those ofO. japonica. The young pinnules ofO. lancea at the initiation of cell expansion are smaller than those ofO. japonica. The growth pattern of the pinnules is fundamentally the same in the two species, but pinnule growth period is shorter inO. lancea than inO. japonica. While the largest growth rate in pinnule length is quite similar, inO. lancea the pinnules are less elongated and much less broadened during ontogeny. Cell expansion in the mesophyll and epidermis proceeds
acropetally and toward the margin along the axes of costules and veins. Although the numbers of mesophyll and epidermal cells
between two adjacent veinlets are almost the same inO. lancea andO. japonica, during the subsequent growth period inO. lancea, the cells expand to a smaller extent and the veinlets become more narrowly oblique to the costule. This oblique distortion
of laminar segments framed by veins causes stenophylly, an allometric modification. The stenophylly ofO. lancea is believed to have arisen by heterochronic evolution, in particular, progenesis. 相似文献
2.
Severe combined immune deficiency (scid) mice are assumed to have two types of abnormalities: one is high radiosensitivity and the other is abnormal recombination
in immunoglobulin and T-cell receptor genes. The human chromosome 8 q1.1 region has an ability to complement the scid aberrations. Moreover, the localization of the subunit DNA-dependent protein kinase [DNA-PKcs] participating in DNA double-strand break repair in the same locus was clarified. In scid mouse cells, the number of DNA-PKcs products and extent of DNA-PK activity remarkably decrease. These observations gave rise to the assumption that DNA-PKcs is the scid factor itself. In order to determine whether the DNA-PK
cs
gene is the scid gene, we isolated the mouse DNA-PK
cs
gene and investigated its chromosomal locus by fluorescence in situ hybridization (FISH). Consequently, it became clear that
the mouse DNA-PK
cs
gene existed in the centromeric region of mouse chromosome 16, determined by cross-genetic study, as a scid locus. This finding strongly suggests that mouse DNA-PK
cs
is the scid gene.
Received: 22 March 1996 相似文献
3.
Fumio Yamazaki Ryoko Sone Nobuharu Fujii Haruo Ikegami 《International journal of biometeorology》1993,37(4):212-217
Based on the hypothesis that the relation between sweating rate and body temperature should be different during exercise and rest after exercise, we compared the sweating response during exercise and recovery at a similar body temperature. Healthy male subjects performed submaximal exercise (Experiment 1) and maximal exercise (Experiment 2) in a room at 27° C and 35% relative humidity. During exercise and recovery of 20 min after exercise, esophageal temperature (Tes), mean skin temperature, mean body temperature (
), chest sweating rate (
), and the frequency of sweat expulsion (F
SW) were measured. In both experiments,
andF
SW were clearly higher during exercise than recovery at a similar body temperature (Tes,
).
was similar during exercise and recovery, or a little less during the former, at a similarF
SW. It is concluded that the sweating rate during exercise is greater than that during recovery at the same body temperature, due to greater central sudomotor activity during exercise. The difference between the two values is thought to be related to non-thermal factors and the rate of change in mean skin temperature. 相似文献
4.
Yoshizawa Itsuo Nagata Kyoko Ohuchi Ryoko Itoh Shinji Kanaiwa Yoshio Amiya Takashi 《Steroids》1980,36(1):87-96
Two D-homosteroids were isolated from the hydrolyzate of 5β-pregnane -3α,20α-diol disulfate (II) when it was refluxed in 3N hydrochloric acid. The structures of these steroids have been elucidated as 17α-methyl-D-homo-5β-androstane-3α, 17aβ-diol (VI) and 17α-methyl-17aγb-chloro-D-homo-5β-androstan-3α-ol (VIII) by instrumental analyses. The former was identical with a synthetic specimen derived from 5β-pregnane-3α,20β-diol di-sulfate (IV) by uranediol rearrangement. The main hydrolyzates obtained were 17α-ethyl-17β-methyl-18-nor-5β-androst-13-en-3α-ol (V) and 5β-pregnane-3α, 20α-diol (III). 相似文献
5.
Ryoko Imaichi 《Journal of plant research》1983,96(3):159-170
The third petiolar bud ofHypolepis punctata appears on the basiscopic lateral side of the petiole above the fairly developed first petiolar bud. This investigation clarified
the fact that the third bud is formed neither by the activity of the meristem of the first bud nor by the meristem directly
detached from the shoot apical meristem, but is initiated in the cells involved in the abaxial basal part of the elevated
portion of the leaf primordium. Thus the third bud is of phyllogenous origin. This investigation further revealed that the
cells to initiate the third bud are originally located in the abaxial side of the leaf apical cell complex like the cells
to initiate the first bud, but are not incorporated into the meristem of the first.
After the first, second and third petiolar buds have been initiated, they are carried up into fairly high regions on the petiolar
base by the intercalary growth which occurs in the leaf base below the insertion level of the first and the second buds. 相似文献
6.
Takeo Kishimoto Ryoko Kuriyama Hisayo Kondo Haruo Kanatani 《Experimental cell research》1982,137(1):121-126
It has been known in amphibians and starfishes that a cytoplasmic factor called maturation-promoting factor (MPF), produced in maturing oocytes under the influence of the maturation-inducing hormones, can induce germinal vesicle breakdown (GVBD) and the subsequent process of meiotic maturation. The present study revealed that injection of cytoplasm of maturing starfish oocytes (starfish MPF) into immature sea cucumber oocytes brought about maturation of the recipients. Amphibian MPF obtained from mature oocytes of Xenopus laevis or Bufo bufo was found to induce maturation of starfish oocytes following injection. Cytoplasm taken from cleaving starfish blastomeres induced maturation when injected into immature starfish oocytes. The maturation-inducing activity of cytoplasm of starfish blastomeres changed along with the mitotic cell cycle during 1- to 4-cell stages so far tested and reached a peak just before cleaving. Furthermore, an extract of mammalian cultured cells, CHO or V-79, synchronized in M phase, induced GVBD in starfish oocytes following injection, whereas S phase extract had little activity. These facts suggest that MPF generally brings about nuclear membrane breakdown in both meiosis and mitosis, and that the nature of MPF is very similar among vertebrates and invertebrates. 相似文献
7.
Ryoko Imaichi 《Journal of plant research》1980,93(1):25-38
Anatomical and developmental studies have been made ofHistiopteris incisa in order to obtain a reasonable interpretation of the so-called extra-axillary bud. Single, or rarely two extra-axillary
buds arise on the lateral side of the petiolar base. The branch trace appears to depart from the basiscopic margin of the
leaf trace. At the earliest stage of the leaf initiation, the leaf apical cell is cut off in one of the prismatic cells of
the shoot apical meristem. The leaf apical cell, then, cuts off segments successively to form a well-defined group of derivatives.
On the other hand, a well-recognized cell group called “outer neighboring cell group”,onc, is found adjacent to the abaxial boundary of the derivatives of the leaf apical cell. This group of cells does not originate
directly in the mother cell of the leaf apical cell. The primordium of the extra-axillary bud is always initiated in the superficial
pillar-shaped cell layer ofonc. The leaf primordium may consist of two parts, the distal part derived from the leaf apical cell and the basal part from
the adjacent cells includingonc. These facts suggest that the extra-axillary bud is of foliar nature.
This study was partly supported by a Grant-in-Aid for Encouragement of Young Scientists by the Ministry of Education of Japan;
no. 374222 in 1978. 相似文献
8.
Ryoko Kakihana 《Life sciences》1976,18(10):1131-1137
The adrenocortical response to ethanol, histamine and electric shock was studied in the Short-Sleep (SS) and Long-Sleep (LS) mice. The plasma corticosterone levels measured at 60 min following ethanol injection were consistently higher in LS mice (males and females) than in SS mice. The corticosterone levels determined 60 min after histamine injection (50 mg/kg) or electric foot shock were not statistically different in these two lines of mice. The initial rise of the corticosteroid after ethanol injection was identical in SS and LS mice, whereas the costicosteroid response to mild stress of saline injection was different: SS mice showed higher levels of corticosterone than LS mice at 20 and 30 min after the injection. Corticosterone increment attributable to alcohol stress clearly seemed greater in LS than in SS mice, even though the adrenals of the SS mice were 20–30% heavier than those of LS. The possible significance of these endocrine differences with respect to sensitivity to ethanol and behavioral arousal level was discussed. 相似文献
9.
In a number of animal species soluble NADH-cytochrome b5 reductase of erythrocytes was compared with membrane-bound NADH-cytochrome b5 reductase of liver microsomes by using an antibody to purified NADH-cytochrome b5 reductase from rat liver microsomes. The results obtained indicated clearly that they are immunologically very similar to each other. The data with erythrocyte ghosts suggested that cytochrome b5 and NADH-cytochrome b5 reductase are also present in the ghost. 相似文献
10.
Takayoshi Yamagishi Toshihiko Serikawa Ryoko Morita Shinichi Nakamura Shoki Nishida 《Microbiology and immunology》1976,20(5):397-403
TSN agar was applicable for enumeration of Clostridium perfringens in fecal samples of adults but not in those of infants. It was demonstrated using TSN agar that some healthy aged adults had persistently carried C. perfringens at levels ranging from 107 to 109, while some others ranged from 103 to 106 per ml volume of fecal sample although all of these adults had the same diets. In the test for agglutinability of isolates of C. perfringens collected from two elderly adults, a younger adult and a baby, it was demonstrated that most of the isolates obtained from an aged adult of high levels for 19 months belonged the same serotype, while rapid alteration of serotypes could be observed in three other persons with high or low levels. In spite of as many as 109 C. perfringens per ml of feces, no trace of α-toxin could be detected in the fecal samples. In in vitro tests, fecal suspension suppressed the production of α-toxin although it allowed the organism to grow sufficiently. 相似文献