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491.
492.
Localization of subspecies of protein kinase C in the mammalian central nervous system 总被引:6,自引:0,他引:6
Activation of protein kinase C (PKC) is regulated by dual second messengers; diacylglycerol (DG) produced by receptor mediated hydrolysis of phosphatidylinositol and Ca2+ which is released by inositol 1,4,5-triphosphate (IP3) from intracellular stores in the endoplasmic reticulum. In the mammalian central nervous system, available evidence suggests that PKC plays a prominent role in the processing of neuronal signals and in the short-term or long-term modulation of synaptic transmission. This enzyme is a member of a family consisting of at least eight subspecies, , βI, βII, γ, δ, , ζ and η. The homologous structure of each subspecies makes difficult resolution of the enzymological properties of the enzyme. The distinct functional roles of PKC subspecies in mammalian tissues have been elucidated by defining the localization of each subspecies. We identified -, βI-, βII- and γ-PKC subspecies in the rat brain by in situ hybridization and by light and electron microscopic immunohistochemistry, using antibodies specific for each subspecies. Most immunoreactions of the , βI, βII and γ subspecies were evident in neurons and there were few, if any, in glial cells. In this article, we summarize known cellular and subcellular localizations of PKC subspecies in mammalian CNS and some aspects of current studies in neuronal functions regulated by this enzyme are discussed. 相似文献
493.
Peter P. Wambua Kazuya Iwabuchi Chikako Iwabuchi Kazumasa Ogasawara Yasushi Itoh Hisashi Arase Masaharu Kajiwara Toshihiko Gotohda Ki-ichi Kajino Robert A. Good Kazunori Ono 《Microbiology and immunology》1994,38(11):879-890
Thymocytes which have developed in the C3H thymus showed depressed proliferative responses to stimulation with anti-CD3 antibody as compared with those which have developed in the thymus of other strains of mice (i.e. AKR). The present study was conducted to analyze immunological functions of the thymic stromal cell population (low-density adherent cells, LDAC) in the C3H mice using allogeneic bone marrow (BM) chimeras established by BM transplantation in the reciprocal combination of AKR and C3H mice as donor or recipient. The thymic LDAC from C3H mice or the [AKR(donor)→C3H(recipient)] chimeras contained a high proportion of Mac-1+ cells as compared to AKR mice or the [C3H→AKR] chimeras. The proportion of Mac-1+ cells paralleled the IL-1- and PGE2-secreting ability of the LDAC cultured either in the presence or absence of LPS and also paralleled the antigen-presenting cell functions of the LDAC. Furthermore, after anti-CD3 stimulation the PGE2 inhibited more profoundly proliferative responses of [AKR→C3H] or normal C3H thymocytes than those of the [C3H→AKR] chimera or normal AKR thymocytes. A PGE2 inhibitor, indomethacin, reversed the depressed responses of the thymocytes which had developed in the C3H thymus. These findings suggest that the lower responsiveness of thymocytes from [AKR→C3H] chimeras to anti-CD3 stimulation may be attributable to large amounts of PGE2 secreted by LDAC and/or to increased sensitivity of thymocytes themselves to PGE2. 相似文献
494.
Maroko Myohara Chikako Yoshida-Noro Fumiko Kobari and Shin Tochinai 《Development, growth & differentiation》1999,41(5):549-555
Enchytraeus japonensis, a recently described terrestrial oligochaete, reproduces asexually by fragmentation and subsequent regeneration. Taking notice of its high potential as a new material for regeneration study, detailed studies were undertaken on the regeneration and reproduction of E. japonensis. The full-grown body divided into 6-13 fragments that regenerated into complete individuals in 4 days, grew to full length in 10 days, and then fragmented again. Regeneration of the head and tail was epimorphic, involving blastema formation, while old segments in the regenerating fragment morphallactically transformed into the appropriate segments to retain the proper body proportions, which could be visualized by histochemistry for alkaline phosphatase. Artificially cut fragments regenerated either normally or into dicephalic monsters with biaxial heads depending on the conditions. Fragmentation could be induced by decapitation, and sexual reproduction was also found inducible in the laboratory. These findings, together with its simple metameric morphology and ease of culture and handling, suggest that E. japonensis is an excellent material for studying animal regeneration. 相似文献
495.
Brown algae are members of the Stramenopiles and their gametes generally have two heterogeneous flagella: a long anterior flagellum (AF) with mastigonemes and a short posterior flagellum (PF). In this study, swimming paths and flagellar waveforms in free-swimming and thigmotactic-swimming male and female gametes and in male gametes during chemotaxis, were quantitatively analysed in the model brown alga Ectocarpus siliculosus. This analysis was performed using a high-speed video camera. It was revealed that the AF plays a role in changing the locomotion of male and female gametes from free-swimming to thigmotactic-swimming and also in changing the swimming path of male gametes from linear to circular during chemotaxis. In the presence of a sex pheromone, male gametes changed their swimming path from linear (swimming path curvature, 0–0.02 µm–1) to middle and small circular path (swimming path curvature, 0.04–0.20 µm–1). The flagellar asymmetry and the deflection angle of the AF became larger, whereas the oscillation pattern of the AF was stable. However, there was no correlation between the flagellar asymmetry and the deflection angle of the AF and the path curvature when the male gametes showed middle to small circular paths. The PF irregularly changed the deflection angle and the oscillation pattern was unstable depending on the gradient of the sex pheromone concentration. AF waveforms were independent of PF locomotion during chemotaxis. This means that the AF has the ability to change the swimming path of male gametes – for example, from a highly linear path to a circular path – while changes in locomotion from a middle circle path to a small circle path is the result of beating of the PF. 相似文献
496.
Shinji Fushiki Chikako Kinoshita Akihiro Nagata Yoko Tsutsumi Yoshio Nishizawa 《The Histochemical journal》1996,28(7):523-530
Summary Different protocols are described for the combined staining method by which argyrophilic nucleolar organizer region sites
can be evaluated in human astrocytes that are immunoreactive for glial fibrillary acidic protein. Among the four protocols
studied, the following method was superior to others in terms of unambiguous visualization of the regions in glial fibrillary
acidic protein-positive astrocytes; the first step was immunostaining for the protein with a blue colour reaction of alkaline
phosphatase, followed by sequential colloidal silver staining for the regions.
By this double staining method, we have demonstrated that the reactive astrocytes found in white matter around the metastatic
lesion of carcinoma and the infarction, contain more argyrophilic nucleolar organizer regions in terms of the count as well
as the area than glial fibrillary acidic protein-positive astrocytes present in the white matter of the normal brain.
In conclusion, the double staining may provide valuable information on the cellular activity of astroglia when performed on
routine formalin-fixed paraffin sections of the human brain. 相似文献
497.
Teratocarcinoma cells have a Ca2+-dependent cell-cell adhesion site (t-CDS) that is unique in being inactivated with trypsin in the absence of Ca2+ but not in the presence of Ca2+. Fab fragments of antibodies raised against teratocarcinoma F9 cells dissociated by treatment with trypsin and calcium (anti-TC-F9) inhibit the aggregation of teratocarcinoma cells mediated by t-CDS. This inhibitory effect of Fab is removed when anti-TC-F9 is absorbed with F9 cells treated with trypsin and calcium (TC-F9), but not when it is absorbed with F9 cells treated with trypsin and EGTA (TE-F9). Comparisons of cell-surface antigens reactive to anti-TC-F9 in TC-F9 cells with those in TE-F9 cells reveal that only one component, with an approximate molecular weight of 140,000 (p140), is detected specifically on the surface of TC-F9 cells. When TC-F9 cells are retrypsinized in the absence of Ca2+, a substance with an approximate molecular weight of 34,000 (p34) is released that can neutralize the aggregation-inhibitory effect of the Fab. This p34 interferes with the immunoprecipitation of p140 with anti-TC-F9, suggesting that p34 is a tryptic fragment of p140. Anti-TC-F9 Fab causes the dissociation of the monolayers of teratocarcinoma cells. This effect is removed by absorption of the Fab with p34 as well as with TC-F9 cells, but not with TE-F9 cells. These results suggest that p140 is essential for the function of t-CDS, and that this is an actual cell-adhesion molecule active in the establishment of monolayers of teratocarcinoma cells. 相似文献
498.
Chiho Kaneko Ryosuke Omori Michihito Sasaki Chikako Kataoka-Nakamura Edgar Simulundu Walter Muleya Ladslav Moonga Joseph Ndebe Bernard M. Hangombe George Dautu Yongjin Qiu Ryo Nakao Masahiro Kajihara Akina Mori-Kajihara Herman M. Chambaro Hideaki Higashi Chihiro Sugimoto Hirofumi Sawa Aaron S. Mweene Ayato Takada Norikazu Isoda 《PLoS neglected tropical diseases》2021,15(4)
BackgroundAn estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries.Methodology/Principal findingsA cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01–0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8–51.6%. This low coverage was principally attributed to the owners’ lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8–76.2%.Conclusions/SignificanceThis paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity. 相似文献
499.
500.
In the cytokinesis of brown algae, actin filaments appear like a plate at the intersecting region of microtubules (MTs) that emerge from the centrosomes after mitosis. The function of the actin plate itself is still unknown. To elucidate the relationship between the actin plate, MTs and membrane fusion, without inducing cytoskeleton depolymerization, the effect of brefeldin A (BFA), which prevents the production of vesicles from Golgi bodies, was examined in zygotes of Silvetia babingtonii. The beginning of mitosis was slightly delayed in zygotes under BFA compared with the controls. Almost all zygotes were inhibited for the progression of cytokinesis by BFA treatment. Ultrastructural observations showed that Golgi cisternae became fragmented or curled following continuous treatment with BFA, and the inhibitory status of cytokinesis between zygotes. The next cell cycle started before cytokinesis was completed. Although the appearance of the actin plate was not disturbed by BFA treatment, the behaviour of the actin plate during the transition between the first and second cell cycles could be classified into two patterns: it was either invisible upon the initiation of the next cell cycle, or a portion of it remained even though the next cell cycle had begun. In the latter case, a part of the actin plate seemed to associate with the new partially formed cell partition membrane, and MTs from the centrosomes were bound to it. The actin plate completely disappeared in the next mitosis, then re-emerged in the middle area of the four daughter nuclei. The results of the present study indicated that, under BFA treatment, the actin plate persisted until just before the beginning of the next mitotic phase, when the new, incomplete cell partition membrane was present, and MTs sustained the actin plate until next mitosis. 相似文献