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71.
Summary The structure of mesenchymal cells distributed in some of the hypendymal organs of the circumventricular system in the cat and rat was demonstrated after intravenous injection of high doses of horseradish peroxidase. These cellular elements were observed in the vicinity of blood vessels of the organon vasculosum laminae terminalis, subfornical organ and area postrema. Electron-microscopically, these cells located between the basal laminae of the brain parenchyma and the blood capillaries show long cellular processes encircling fenestrated capillaries. Light and electron-microscopic examination revealed that this cell type is identical with the horseradish peroxidase-uptake cells, previously reported in the vicinity of the hypophysial portal system. Such phagocytic cells may be considered as a cellular component intervening between the brain parenchyma and the blood stream, playing a role in selective barrier functions in the above-mentioned circumventricular organs where a blood-brain barrier in the classical sense of the definition is lacking.This work was supported by grant No. 437002 from the Ministry of Education, Science and Culture, Japan 相似文献
72.
Leaves of different ages from B. calycinum were exposed to 14CO2in light during day and night. The labelling pattern on thechromatogram differed with leaf age. Young leaves had similarpatterns to those of C3 plants during both day and night. Matureleaves showed high incorporation of 14C into C4 acids, especiallyat night. In contrast, no significant difference with leaf agewas observed in the pattern of dark 14CO2 fixation products.Study of the enzyme activity and the content of titratable acidat each leaf age suggested that high incorporation of 14C inC4 acids during the night was due to the simultaneous absorptionof CO2 by both enzymes RuDPcarboxylase and PEPcarboxylase. (Received November 24, 1977; ) 相似文献
73.
74.
Y Kitajima S Matsuhashi H Nishida Y Takasaki I Takahashi T Hisatsugu K Hori 《Journal of biochemistry》1991,109(4):544-550
Three monoclonal antibodies (MAbs1A2, 3C5, and 4C2) for human aldolase A [EC 4.1.2.13] were established. MAbs1A2, 3C5, and 4C2 were shown to belong to subclasses IgM, IgG1, and IgG2a, respectively. None of the MAbs inhibits aldolase A activity. Their epitopes were mapped in detail on the molecule by examining the reactivities of the MAbs to chimeric proteins between aldolases A and B [Kitajima et al. (1990) J. Biol. Chem. 265, 17493-17498] in ELISA and to the CNBr-cleaved fragments of aldolase A in immuno-blotting. MAbs1A2 and 3C5 reacted with sites located within amino acid residues 306-363 at the C-terminal region of the enzyme. MAb4C2 recognized an epitope of the enzyme present within amino acid residues 34-108 at the N-terminal region. In a competitive binding assay, MAbs1A2 and 3C5 competed with each other for binding to the antigen and also interfered with the binding of MAb4C2, whereas MAb4C2 failed to inhibit the binding of MAbs1A2 and 3C5 to the antigen. MAb3C5 showed a species-specificity in the reaction with the antigen; it reacted with human and rabbit aldolase A with similar reactivity but not at all with the rat and mouse enzymes, which differ from the human and rabbit enzymes in two amino acid residues at positions 328 and 348. Reactivities of MAbs to aldolase A were further examined with engineered enzymes containing an amino acid substitution.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
75.
Tokuo Ogawa Junichi Sugenoya Norikazu Ohnishi Keiko Natsume Megumi Ochiai Motohiko Nishida Norihiko Shinoda Kenichi Katoh Ritsuko Imamura 《International journal of biometeorology》1991,35(1):18-23
In an attempt to detect differences in the thermal effect of infrared irradiation of different wavelengths, transient sweating response to infrared irradiation in various spectral regions was examined. In Series 1, the ventral or dorsal surface of the nude subject was irradiated repetitively for a period of 4 min (2 min on, 2 min off) by each of three kinds of infrared heaters with main emissivity in near-infrared (NIR; 0.7–2.8 m), intermediate-infrared (MIR; 1.5–5.8 m), and far-infrared (FIR; 2.8–25 m) regions. The sweating response on a non-irradiated area tended to be the greatest with MIR, while the magnitude of the sweating response on the irradiated area showed no consistent differences among various wavelengths. The results infer that MIR stimulated cutaneous thomoreceptors most effectively, while its direct effect on local sweat gland activity was minimal. In Series 2, the effects of 9–12 min irradiations in more restricted ranges of wavelength were compared by the combination of the three kinds of heaters with filters (translucent to wavelength ranges of 1.3–2.7, 2.7–3.5, 3.6–8.0 m, respectively). The sweating response on a remote area was predominantly greater with the range of 2.7–3.5 m than with the other wavelength ranges, while the local effect on sweating was minimal with this range. The results of Series 2 reinforce those of Series 1, indicating that the degree of stimulation of cutaneous thermoreceptors and of direct thermal effect on sweat gland activity differ with spectral regions incident on the skin, thus affecting local and remote effects on the sweating response. 相似文献
76.
The mitogen-activated protein (MAP) kinases, a family of 40-45-kDa kinases whose activation requires both tyrosine and threonine/serine phosphorylations, are suggested to play key roles in various phosphorylation cascades. A previous study of Krebs and co-workers (Ahn, N. G., Seger, R., Bratlien, R. L., Diltz, C. D., Tonks, N. K., and Krebs, E. G. (1991) J. Biol. Chem. 266, 4220-4227) detected an activity in epidermal growth factor (EGF)-stimulated 3T3 cells that can stimulate inactive MAP kinases. We observed this activity in rat 3Y1 cells treated with various mitogenic factors and in PC12 cells treated with nerve growth factor (NGF). Its kinetics of activation and deactivation following EGF or NGF stimulation roughly paralleled that of MAP kinase. The MAP kinase activator required the presence of ATP and a divalent cation such as Mn2+ and Mg2+ and was inactivated by phosphatase 2A treatment in vitro. This activator has been isolated from EGF-stimulated 3Y1 cells by sequential chromatography and identified as a 45-kDa monomeric protein. It was able to activate mammalian and Xenopus MAP kinases in vitro and was very similar to Xenopus M phase MAP kinase activating factor, which was purified previously from mature oocytes (Matsuda, S., Kosako, H., Takenaka, K., Moriyama, K., Sakai, H., Akiyama, T., Gotoh, Y., and Nishida, E. (1992) EMBO J. 11, 973-982), in terms of its functional, immunological, and physicochemical properties. Thus, the same or a similar upstream activating factor may function in mitogen-induced and M phase-promoting factor-induced MAP kinase activation pathways. 相似文献
77.
Activation of mitogen-activated protein kinase and its activator by ras in intact cells and in a cell-free system. 总被引:10,自引:0,他引:10
S Hattori M Fukuda T Yamashita S Nakamura Y Gotoh E Nishida 《The Journal of biological chemistry》1992,267(28):20346-20351
Mitogen-activated protein (MAP) kinase is a serine/threonine kinase whose function is thought to be essential for the transduction of mitogenic signals. MAP kinase is activated by phosphorylation induced by a variety of extracellular stimuli, and its direct upstream activator has been identified. Using amphibian and mammalian systems, we show here that ras can activate MAP kinase and its activator. Injection of v-Ha-ras p21 into Xenopus immature oocytes activated both MAP kinase and maturation-promoting factor (MPF) activities. The activation of MAP kinase preceded that of MPF, demonstrating that ras activates MAP kinase in an MPF-independent pathway. Moreover, we found that the MAP kinase activator is also activated in ras-injected oocytes. Activation of MAP kinase and its activator occurred also when the v-Ki-ras gene was conditionally induced in rat fibroblastic 3Y1 cells. Furthermore, we observed that ras activated MAP kinase and its activator in a cell-free system prepared from Xenopus oocytes. Using an antibody against the Xenopus 45-kDa MAP kinase activator, we demonstrated that the 45-kDa activator molecule was activated by ras. These findings suggest that the MAP kinase activator/MAP kinase system may be the downstream components of ras signal transduction pathways. 相似文献
78.
Miya Hamai Toshisada Nishida Hiroyuki Takasaki Linda A. Turner 《Primates; journal of primatology》1992,33(2):151-162
Two cases of within-group infanticide and cannibalism were observed among the M Group chimpanzees of the Mahale Mountains,
Tanzania. In both cases, victimized infants were male, 5 – 6 months of age, and in good health when killed. Four to five years
have passed since the mothers of the victims immigrated into M Group as nulliparous immigrants. In one case the 2nd-ranking
male was observed to detach the infant from the mother's belly. Both infants were finally killed by the alpha male after several
adult males scrambled for the bodies. There was no evidence that the mothers had mated with males other than those of M Group.
Nor was there evidence that the mothers had restrictive mating relationships with some of the M Group adult males. What little
evidence is available shows that the mothers had mated mostly with adolescent and other immature males during their conception
cycles. However, at least in one case, the mother began to mate more with adult males rather than with immature males after
the infanticide. It is proposed that the function of within-group male infanticide can be explained by the male-male competition
hypothesis developed for hanuman langurs and other nonhuman primates. 相似文献
79.
Harufumi Nishida 《Journal of plant research》1991,104(3):253-273
Middle to Late Cretaceous permineralized plants hitherto described from Hokkaido, Japan are summarized. The fossil flora comprises
fungi, ferns, gymnosperms and angiosperms. Many modern fern families have been recognized including Anemiaceae, Cyatheaceae,
Dennstaedtiaceae, Gleicheniaceae Loxsomaceae, Lygodiaceae and Matoniaceae. Gymnosperms are most abundant in the flora. Some
recently-found materials are tentatively introduced with brief comments emphasizing their morphological and taxonomical significance.
A bisporangiate flower ofCycadeoidella japonica Ogura shows fine internal anatomy and provides evidence that the cycadeoidalean ovule was a cupulate, unitegmic structure.
Vascular tracheids in the synangial wall support the evolution of cycadeoidalean synangia from Paleozoic seed-fern synangia.
A new gymnosperm female fructification has a thick envelope comparable to an angiosperm carpel around a large seed. The angiosperms
contain various morphologies that require further extensive study. 相似文献
80.
Fluorescent microscopy was proved to be effective for structural identification of permineralized plant tissues in calcite
nodules from the Upper Cretaceous of Hokkaido, Japan. A minute, scale-like projection on the bract of a fossil Taxodiaceous
cone is identified as a true ovuliferous scale because it is bordered with a continuous epidermis that exhibits prominent
fluorescence. The presence of the ovuliferous scale suggests that the fossil is aTaiwania archetype. 相似文献