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排序方式: 共有1532条查询结果,搜索用时 15 毫秒
1.
Shigeo Koyasu Makoto Asada Akio Fukuda Yoshimi Okada 《Journal of molecular biology》1981,153(2):471-475
The mode of polymerization of two species of flagellins, flagellin A and flagellin B, in polar flagella of Caulobacter crescentus was examined. By immunological staining we found that 1 to 1.2 μm of the portion of the flagellar filament proximal to the cell was composed of flagellin B, whereas about 5 μm of the distal portion was composed of flagellin A. This result, together with the previous observation that a flagellin B-less mutant cannot form normal flagella but instead forms stubs in spite of their high level of flagellin A synthesis, indicates that flagellin B is very important for the formation of complete flagella and/or for the initiation of filament formation from the hook. 相似文献
2.
Shinsaku Tokuda Young Hak Kim Hisako Matsumoto Shigeo Muro Toyohiro Hirai Michiaki Mishima Mikio Furuse 《PloS one》2015,10(12)
The relationship between chronic inflammation and cancer is well known. The inflammation increases the permeability of blood vessels and consequently elevates pressure in the interstitial tissues. However, there have been only a few reports on the effects of hydrostatic pressure on cultured cells, and the relationship between elevated hydrostatic pressure and cell properties related to malignant tumors is less well understood. Therefore, we investigated the effects of hydrostatic pressure on the cultured epithelial cells seeded on permeable filters. Surprisingly, hydrostatic pressure from basal to apical side induced epithelial stratification in Madin-Darby canine kidney (MDCK) I and Caco-2 cells, and cavities with microvilli and tight junctions around their surfaces were formed within the multi-layered epithelia. The hydrostatic pressure gradient also promoted cell proliferation, suppressed cell apoptosis, and increased transepithelial ion permeability. The inhibition of protein kinase A (PKA) promoted epithelial stratification by the hydrostatic pressure whereas the activation of PKA led to suppressed epithelial stratification. These results indicate the role of the hydrostatic pressure gradient in the regulation of various epithelial cell functions. The findings in this study may provide clues for the development of a novel strategy for the treatment of the carcinoma. 相似文献
3.
Atsuko Matsuoka Akiko Hirosawa Shinasku Natori Shigeo Iwasaki Toshio Sofuni Motoi Ishidate Jr. 《Mutation research》1989,215(2):179-185
The chromosomal aberration test using a Chinese hamster lung cell line (CHL) was carried out on ptaquiloside and its related compounds, hypoloside B, hypoloside C, illudin M and illudin S. Ptaquiloside induced chromosomal aberrations at doses as low as 4.5 μg/ml (0.0113 mM). The clastogenic effect was ph-dependent. The same activity was observed at a 90-fold higher dose at pH 5.3 in the culture medium compared with the activity at pH 74. or pH 8.0. Both hypoloside B and hypoloside C were also clastogenic at almost the same dose levels as that of ptaquiloside. Illudin M and illudin S were also potet clastogens and induced aberrations at much lower doses than ptaquiloside. These results suggest that the clastogenic effect is involved in the mechanism of carcinogenic potency of ptaquiloside in animals. 相似文献
4.
Yasuaki Kagotani Setsuji Hisano Yoshihiro Tsuruo Shigeo Daikoku Yasuhiko Okimura Kazuo Chihara 《Cell and tissue research》1990,262(1):47-52
Summary Certain populations of arginine vasopressin (AVP) neurons in the magnocellular paraventricular nucleus became immunoreactive for neuropeptide Y (NPY) when rats were treated with colchicine or monosodium glutamate (MSG). The co-storage of these peptides was examined by empooying a post-embedding electron-microscopic immunohistochemistry technique using goldlabeled antibodies to the two peptides. In colchicinetreated rats, the neuronal perikarya contained numerous secretory granules showing co-storage of the two peptides. The cells of the MSG-treated rats were characterized by having well-developed Golgi bodies with the granular structures also co-storing the two peptides, although the secretory granules in the perikarya were rather fewer than in the colchicine-treated rats. It is concluded that the destruction of the arcuate nucleus by MSG-treatment may potentiate the synthesis of NPY in AVP neurons, the synthesis of which is latent in intact animals. 相似文献
5.
Midori Hiramatsu Rei Edamatsu Shigeo Suzuki Masakazu Shimada Akitane Mori 《Neurochemical research》1990,15(8):821-825
Inbred mutant El mice are highly susceptible to convulsive seizures upon tossing stimulation. The levels of excitatory (e.g. glutamate and aspartate) and inhibitory amino acids [e.g. -aminobutyrate (GABA)] were examined in discrete regions of stimulated El mice [El(+)] non-stimulated El mice [El(-)] and ddY mice, which do not have convulsive disposition. In comparison with ddY, a general increased levels of aspartate, glutamate, glutamine, and taurine were detected in brain regions of El(-). The levels of GABA and glycine were almost the same in ddY and El(-). Compared to El(+), the levels of aspartate, glutamate, glutamine, and GABA in El(-) were either the same or higher. In the case of taurine and glycine, the levels in El(-) were either the same or lower than El(+). Alanine is special in that El(-) have a higher level than El(+) in hippocampus but lower in cerebellum. Furthermore, while marked changes were registered in several brain regions, none of the amino acids investigated showed any significant differences in the hypothalamus of three different groups of mice. 相似文献
6.
Naoki Kachi 《Ecological Research》1990,5(2):185-194
A study was conducted on the germination traits and seed-bank dynamics ofOenothera glazioviana (=O. erythrosepala), which sets seed in August in sand-dune systems in Japan. More than 90% of freshly matured seeds germinated over a wide
range of temperature in light, but less than 10% did so in continuous darkness. Stratification (chilling under moist conditions)
was ineffective in diminishing the light-requirement for germination. When fresh seeds were imbibed for 24 h including a 12-h
light period, followed by 7-day air-drying, 94% of them became germinable in the dark at 25°C, but remained dormant at less
than 15°C. of seeds collected in March from capsules of dead plants, 58% germinated in the dark at 25°C. After four cycles
of alternatc 1-day wetting followed by 2-day drying or 1.5-day wetting followed by 1.5-day drying under a 12-h photoperiod,
the fraction of viable seeds declined from 76% to 40% and 22%, respectively, due to germination during the wet periods.
Seed-bag experiments were conducted in the field, using seeds given and not given a light-stimulus. Forty percent of the light-stimulated
seeds germinated in the soil, whereas the seeds without a light-stimulus remained dormant throughout the experiment. When
seeds were placed on the soil surface or at a depth of 0.5-1 cm, the proportion of germinable seeds declined during late spring
and autumn, but not during winter and early spring. The seed-bank size of a natural population just prior to current seed
dispersal was 2–3% of the seed production in the previous year, suggesting a high turnover rate of the seed-bank. 相似文献
7.
Dr. Ritsuko Katoh-Semba Hiroomi Keino Shigeo Kashiwamata 《Cell and tissue research》1988,252(1):133-139
Summary Recent reports have revealed that certain neurons do not survive in vitro in the presence of glucose, which is the primary substrate and exclusive source of energy in the brain. But these neurons can survive in the presence of low-molecular-weight agents such as pyruvate, which are supplied by glial cells (Selak et al. 1984). To test whether this result also holds true in vivo, we investigated the distribution of hexokinase, lipoic dehydrogenase, -hydroxybutyrate dehydrogenase, and glucose-6-phosphate dehydrogenase activities in the developing rat cerebellum. Hexokinase activity was relatively higher in glial cells than in neurons. After postnatal day 8, the activity of hexokinase could hardly be detected in Purkinje cells, whereas it was highest in Bergmann glial cells. Purkinje cells were the only type of neuron with high levels of lipoic dehydrogenase at all ages tested. -Hydroxybutylate dehydrogenase activity was also high in Purkinje cells, especially in those from young rats. Relatively high glucose-6-phosphate dehydrogenase activity was demonstrated in basket and stellate cells from adult brain. Thus, it appears that, in vivo, certain neurons utilize relatively little glucose, and it is indeed possible that glial cells may supply some substance(s) other than glucose, for example pyruvate, as the primary source of energy. 相似文献
8.
Reinhard Renneberg Kenji Sonomoto Shigeo Katoh Atsuo Tanaka 《Applied microbiology and biotechnology》1988,28(1):1-7
Summary The oxygen-diffusivity (D
m
) of 16 different gels formed with synthetic prepolymers (photo-crosslinkable resins, urethane resins and photosensitive resins), and that of calcium alginate (for comparison) was determined, using an oxygen electrode covered by the gel membranes with stepwise enzymatic removal of O2 from the buffer solution. The water content of the gels was found to be decisive for the O2-diffusivity of the gels: gels with the highest water content showed also the highest D
m
. From these findings, the suitability of different polymeric gels for substrate conversion and biosensor systems could be predicted.Abbreviations
A
surface area of the cathode
-
c
O2-concentration in the membrane
-
d
m
total thickness of the membrane
-
D
m
O2-diffusivity in the membrane
- ENT, ENTP
polymers prepared from hydroxyethylacrylate
- ENTA, ENTC
isophorone diisocyanate and linear skeleton of different molecular weight of poly(ethylene glycol) (ENT) or poly(propylene glycol) (ENTP), resp. ENTA in addition bears anionic groups, ENTC cationic groups
-
F
Faraday's constant
-
i
s
steady-state O2 reduction current
-
N
number of electrons per mole unit of reaction
- PU
polyurethane polymers with poly(ethylene glycol) and poly(propylene glycol) parts in the diol moiety and isocyanate functional groups at both terminals of the prepolymer
- PVA-SbQ
polyvinyl alcohol stilbazolium polymer 相似文献
9.
Sachiko Aono Hiroshi Sato Reiji Semba Shigeo Kashiwamata Kanefusa Kato † Lawrence F. Eng† 《Journal of neurochemistry》1988,50(3):717-721
The behavior of marker proteins of glial cells [alpha-enolase, beta-S100 protein, and glial fibrillary acidic protein (GFAP)] was investigated quantitatively by using enzyme immunoassay systems during the development of cerebellar hypoplasia in jaundiced Gunn rats. A neuronal marker protein, gamma-enolase, was also measured as a reference. At postnatal day 8 corresponding to the early stage of cerebellar damage, the amount of beta-S100 on a protein basis was significantly higher in jaundiced homozygotes (jj) than in control nonjaundiced heterozygotes (j+), whereas no differences in alpha- and gamma-enolases and GFAP were observed between the two groups of rats. At days 15 and 30, which correspond, respectively, to the advanced and late stages of cerebellar damage, the three glial proteins, especially GFAP, were higher and the neuronal protein was lower in the jj rat cerebellum than in the control. These results are consistent with the reported histological observations that neuronal cells are vulnerable and damaged by bilirubin, whereas glial cells seem to be less sensitive. On the other hand, the amounts of beta-S100 and alpha-enolase per cerebellum were significantly lower in jj rats at days 15 and 30, as in the case of gamma-enolase, whereas that of GFAP remained at the same level as the control at day 15 and showed a slight but significant decrease at day 30. The possibility is suggested that beta-S100 and GFAP may be available as biochemical indicators of glial cells, especially in the early and advanced stages of cerebellar damage, respectively, but that alpha-enolase is less available. 相似文献
10.
Responses of seed germination to salinity were examined using 37 species collected from salt marshes, cliffs, and fore (unstable)
and hind (stable) sand dunes along Japanese coasts. For comparison, seed germination of nine inland species was also examined.
The soil salinities in salt marshes ranged from 150 to 300 mmol/L NaCl, whereas those in fore and hind dunes ranged from 0
to 150 mmol/L NaCl, with a few exceptions. Cliff soils showed relatively high salinities up to 300 mmol/L NaCl. Ciff and foredune
soils that encountered a typhoon and storm showed high salinities >300 mmol/L NaCl. Salt tolerance in seed germination of
coastal plants was ordered by comparing the responses of percentage and rate of germination to salinity conditions up to 200
mmol/L NaCl, being in the order of salt marsh>cliff>foredune≅hind dune≅inland. Thse results indicate that salt tolerance in
seed germination of coastal plants is closely related to the salinity conditions of their habitats. Germination experiments
under favorable conditions showed that a high percentage of the seeds of salt marsh species germinate rapidly, those of diff
species germinate slowly and those of foredune species exhibit a low percentage and low rate of germination. It seems that
these germination characteristics contribute to the success of germination at the ‘safe site’ and the subsequent survivorship
of emerged plants in their natural habitats. 相似文献