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1.
The photosystem II core complex purified from digitonin extractsof spinach chloroplasts was resolved into two chlorophyll-proteincomplexes by digitonin polyacrylamide gel electrophoresis aftertreatment with 1 M potassium thiocyanate. One of the chlorophyll-proteincomplexes resolved consisted of 47, 32, 30 and 9 kDa polypeptidesand the other was complementally composed of only the 43 kDapolypeptide. The former complex was highly active in the photoreductionof 2, 6-dichlorophenol indophenol by 1,5-diphenylcarbazide andretained all of the components responsible for the electrontransport from the secondary electron donor (Z) to the primaryelectron acceptor (QA). EPR signal IIfast and IIslow were alsopreserved in this complex although their hyperfine structureswere largely modified. The complex was estimated to contain1.8 molecules of plastoquinone A as well as 1.5, 3.7 and 3.9molecules of cytochrome b559, pheophytin and ß-carotene,respectively, per QA. These results indicate that potassiumthiocyanate specifically removes the 43 kDa polypeptide fromthe PS II core complex leaving the electron transport systemin an almost intact state. (Received June 17, 1987; Accepted October 23, 1987) 相似文献
2.
Ryozo Oishi Naoto Adachi Keishi Okada Nobuyuki Muroi Kiyomi Saeki 《Journal of neurochemistry》1990,55(6):1899-1904
To clarify the regulation of central histaminergic (HAergic) activity by cholinergic receptors, the effects of drugs that stimulate the cholinergic system on brain histamine (HA) turnover were examined, in vivo, in mice and rats. The HA turnover was estimated from the accumulation of tele-methylhistamine (t-MH) during the 90-min period after administration of pargyline (65 mg/kg, i.p.). In the whole brain of mice, oxotremorine, at doses higher than 0.05 mg/kg, s.c., significantly inhibited the HA turnover, this effect being completely antagonized by atropine but not by methylatropine. A large dose of nicotine (10 mg/kg, s.c.) also significantly inhibited the HA turnover. This inhibitory effect was antagonized by mecamylamine but not by atropine or hexamethonium. A cholinesterase inhibitor, physostigmine, at doses higher than 0.1 mg/kg, s.c., significantly inhibited the HA turnover. This effect was antagonized by atropine but not at all by mecamylamine. None of these cholinergic antagonists used affected the steady-state t-MH level or HA turnover by themselves. In the rat brain, physostigmine (0.1 and 0.3 mg/kg, s.c.) also decreased the HA turnover. This inhibitory effect of physostigmine was especially marked in the striatum and cerebral cortex where muscarinic receptors are present in high density. Oxotremorine (0.2 mg/kg, s.c.) and nicotine (1 mg/kg, s.c.) also decreased the HA turnover in the rat brain. However, these effects showed no marked regional differences. These results suggest that the stimulation of central muscarinic receptors potently inhibits the HAergic activity in the brain and that strong stimulation of central nicotinic receptors can also induce a similar effect. 相似文献
3.
Recombinational hotspot specific to female meiosis in the mouse major histocompatibility complex 总被引:13,自引:0,他引:13
Toshihiko Shiroishi Naoto Hanzawa Tomoko Sagai Masahiro Ishiura Takashi Gojobori Michael Steinmetz Kazuo Moriwaki 《Immunogenetics》1990,31(2):79-88
Thewm7 haplotype of the major histocompatibility complex (MHC), derived from the Japanese wild mouseMus musculus molossinus, enhances recombination specific to female meiosis in theK/A
interval of the MHC. We have mapped crossover points of fifteen independent recombinants from genetic crosses of thewm7 and laboratory haplotypes. Most of them were confined to a short segment of approximately 1 kilobase (kb) of DNA between theA
3 andA
2 genes, indicating the presence of a female-specific recombinational hotspot. Its location overlaps with a sex-independent hotspot previously identified in theMus musculus castaneus CAS3 haplotype. We have cloned and sequenced DNA fragments surrounding the hotspot from thewm7 haplotype and the corresponding regions from the hotspot-negative B10.A and C57BL/10 strains. There is no significant difference between the sequences of these three strains, or between these and the published sequences of the CAS3 and C57BL/6 strains. However, a comparison of this A3/A2 hotspot with a previously characterized hotspot in theE gene revealed that they have a very similar molecular organization. Each hotspot consists of two elements, the consensus sequence of the mouse middle repetitive MT family and the tetrameric repeated sequences, which are separated by 1 kb of DNA.The nucleotide sequence data reported in this paper have been submitted to the DNA Data Bank of Japan nucleotide sequence database and have been assigned the accession numbers d90007-9.
Offprint requests to: T. Shiroishi. 相似文献
4.
Naoto Sugiura 《Journal of Ethology》1994,12(2):131-139
Anthidium septemspinosum is a solitary, tube-nesting bee. Studies onA. septemspinosum were made to investigate how offspring sex ratios were influenced by maternal conditions. Males were generally larger than
females, indicating that parental investment between sexes differed. Body size was related to male mating success, but was
not related to nesting success of females. Large and young mother bees, who had more ability to invest, invested more in male
offspring while small and old mothers invested more in female offspring. These results indicate that mother bees of this species
are able to adaptively manipulate offspring sex ratio in relation to their ability to invest in offspring, as predicted in
mammals by Trivers & Willard (1973). 相似文献
5.
Postnatal change in the distribution of actin filaments in endothelial cells was studied in the rat aorta by use of rhodamine-phalloidin staining and confocal laser scanning microscopy. Endothelial cells of the rat aorta possessed two populations of actin filament bundles, namely, peripheral bands at the cell border and stress fibers running longitudinally in the cytoplasm. Aortic endothelial cells of the neonatal rat contained only stress fibers, whereas those of the 10-day-old rat developed both peripheral bands and stress fibers. After 20 days of age, aortic endothelial cells had predominantly peripheral bands with occasional stress fibers around the branch orifices. During postnatal development the length density of stress fibers in aortic endothelial cells decreased, whereas individual stress fibers in endothelial cells were shortened. Electron-microscopic observation revealed that the high intercellular boundaries of aortic endothelial cells at birth decreased in height and developed cytoplasmic interdigitations after 20 days of age. The occurrence of peripheral bands at the cell border is thought to be closely related to formation of cytoplasmic interdigitation which strengthens the mechanical connection between endothelial cells against increasing transmural pressure. Expression of stress fibers in aortic endothelial cells of the neonatal rat is supposed to be affected by longitudinal elongation of the developing aorta, whereas their postnatal decrease is though to be correlated with the change of fluid shear stress loaded in the aortic endothelium. 相似文献
6.
Elucidation of the mechanism enhancing the avidity of lectin with oligosaccharides on the solid phase surface 总被引:3,自引:2,他引:1
The mechanism underlying molecular recognition of lectins waselucidated by a novel solid phase binding assay system basedon surface plasmon resonance. When the apparent affinities ofinteractions between chitooligosaccharides and wheat germ agglutininwere compared between lectin-immobilized and oligosaccharide-immobilizedassay systems, the affinity constants (Ka) calculated for theformer system were in good agreement with the previously reportedvalues measured in solution. On the other hand, in the lattersystem, the calculated Ka could be more than 10,000 times higherthan the values in solution at lower lee tin concentrations.To elucidate the reason for this, we systematically investigatedthe effects of the oligosaccha-ride immobilized density andthe lectin valence on the apparent affinity in the oligosaccharide-immobilizedassay system. Both the apparent association (kass) and dissociationrate constants (kdiss) showed a tendency to decrease as theoligosaccharide density increased. This effect was most remarkablefor the interaction possessing an extremely fast intrinsic Kass.Oligomerization of lectin enhanced the avidity due to a significantreduction in kdiss. These phenomena could be explained by consideringthe nonhomogeneous conditions under which binding occurred.The reaction in a nonhomogeneous state is limited by the masstransport effect, and the effect of rebinding becomes so largethat it cannot be disregarded. These findings are the firstto demonstrate the importance of the mass transport effect inmodulating the affinity of lectin for oligosaccharides on asolid phase surface. avidity clustering effect lectin mass transport surface plasmon resonance 相似文献
7.
Naoto Sugiura 《Ecological Research》1995,10(2):171-177
Anthecological observations of an orchidBletilla striata were carried out in Kobe, Japan. The purplish pink flowers were visited by 26 species of insects belonging to Hymenoptera,
Diptera and Lepidoptera, although the flower did not offer food rewards of any kind. Candidates for pollination were seven
species of aculeate Hymenoptera with a body size that well fitted the space in between the column and labellum. The most effective
candidate was the male of the longhorn beeTetralonia nipponensis, judging from its abundance and legitimate intrafloral behavior. The female ofT. nipponensis and the other six species also contributed to promote out-crossing, but to a lesser extent than the maleT. nipponensis, since they occasionally exhibited illegitimate intrafloral behaviors for pollination and also, their flower visitation rate
was lower. 相似文献
8.
9.
OsWRKY28, a PAMP-responsive transrepressor, negatively regulates innate immune responses in rice against rice blast fungus 总被引:1,自引:0,他引:1
10.