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411.
Flow of Latex suspension with high concentration between plate glasses was observed through an optical microscope. Size of aggregates of Latex particles was estimated by measuring area of a region without particles behind an obstacle in the flow region (this technique had been developed by one of the authors). At the same time, viscosity and elasticity of the suspension were measured by a cone-plate viscometer, and relations between the aggregate size and these properties were obtained. A simple model based on the Stokes law of resistance and the Maxwell model for viscoelastic materials is proposed to explain these relations. The theoretical results agree with the present experiment. 相似文献
412.
Plant pigments: the many faces of light perception 总被引:1,自引:0,他引:1
Rog��rio Falleiros Carvalho Massanori Takaki Ricardo Antunes Azevedo 《Acta Physiologiae Plantarum》2011,33(2):241-248
Good reviews have been published over the years regarding many aspects of plant response to light, such as important advances in understanding the molecular mechanisms of light perception, signaling and control of gene expression by the photoreceptors. Moreover, many efforts have been undertaken on the manipulation of these mechanisms to improve horticultural crop production. In this paper we present an overview about the photoreceptors, the relationship between their absorptive and reflective properties and their control of plant development as well perspectives focused on photomorphogenesis manipulation. 相似文献
413.
Yoshihide Takaki Takayuki Kawahara Hisashi Kitamura Ko-ichi Endo Takuma Kudo 《Conservation Genetics》2009,10(2):269-279
Japanese goshawk was classified as a vulnerable species in the Red Data Book. There have been possibilities of a decrease
of genetic diversity accompanied by habitat loss and genetic pollution due to hybridization with escaping imported goshawks.
In this paper, genetic diversity, gene flow and conservation of Northern Goshawk (Accipiter gentilis) in Japan are discussed and compared with that in Central Asia. We used 11 newly developed microsatellite markers and also
adopted six previously published markers. Genetic diversity was shown to be maintained with 0.58 as mean heterozygosity and
3.95 as mean allelic richness. The degree of genetic differentiation across all populations was low (Nei’s genetic differentiation
index = 0.036, Wright’s genetic differentiation index = 0.039), possibly due to gene flow via adjacent regions (average number
of migrants = 4.26; 0.68–20.30). However, it is possible that slight differentiation resulted from the short divergence time
and/or inflow of escaping imported individuals. We recommend that goshawks in eastern Japan should be managed as a single
unit. They do not appear to be under threat genetically at present, but there is the potential for rapid loss of genetic diversity.
For future conservation, investigations of dispersal routes and actual conditions of gene flow are also recommended. To prevent
further inflow of escaping goshawks into natural populations, it is desirable to reduce importation of goshawks and to enact
a regulation obliging purchasers to register imported goshawks.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
414.
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416.
Conditioned medium from density-inhibited V79 Chinese hamster cell cultures, given as a post-treatment to UV-irradiated homologous cells, was demonstrated to reduce the lethal action of ultraviolet light by temporarily blocking DNA replication. Since the increased survival was not affected by various nontoxic concentrations of caffeine, such protective effect would be attributable to the prolonged intervention of excision repair before DNA replication during the post-treatment period. The influence of conditioned medium on the UV-induced mutation at the ouabain-resistance locus was also examined and a significant decrease in mutation frequency was noted. The observed reduction in killing and mutation as a result of post-incubation in conditioned medium, which delays DNA replication, would be interpreted as evidence that conditioned medium provides a longer period of time for an error-free excision-repair process, leaving lesion in DNA available for error-prone post-replication repair. 相似文献
417.
418.
R. Takaki J. Ono M. Nakamura Y. Yokogawa S. Kumae T. Hiraoka K. Yamaguchi K. Hamaguchi S. Uchida 《In vitro cellular & developmental biology. Plant》1986,22(3):120-126
Summary Six glucagon-secreting cell lines designated as In-R1G1,-G3,-G7,-G9,-G10, and-G11 were isolated from insulinoma cells (In-111-R1)
by single cell cloning. A small amount of insulin was also detectable in the incubation medium when hormone secretion was
stimulated by the addition of arginine or theophylline. These cell lines grew as monolayers and the population doubling times
varied from 16.8 to 28.8 h. Karyologically these clones were aneuploid and the modes of chromosome numbers were 61 to 70.
Electron microscopic examination of one of these clones showed that these cells contained moderately developed Golgi apparatus
and a few secretory granules, which more or less resembled α-cell granules. By gell filtration study of the incubation medium,
glucagon and glucagonlike material were eluted. The molecular weight of the latter was approximately 9000, which suggested
the concomitant secretion of rpoglucagon into the medium. The levels of secreted glucagon in basal state were 0.3 to 3.0 ng/106 cells/2 h. Glucagon secretion was markedly enhanced in the presence of amino acids. Glucagon secretion increased slightly
in the presence of high concentration of glucose in Hanks' balanced salt solution; however it was not affected by the varying
concentrations of glucose when the cells were incubated in complete media with amino acids. Glucagon secretion was also stimulated
by the addition of theophylline. These clonal cell lines seem to provide a useful tool for investigating the mechanism of
glucagon secretion. 相似文献
419.
Yukari Yoshida-Takashima Yoshihiro Takaki Shigeru Shimamura Takuro Nunoura Ken Takai 《Extremophiles : life under extreme conditions》2013,17(3):405-419
Epsilonproteobacteria are among the predominant primary producers in deep-sea hydrothermal vent ecosystems. However, phages infecting deep-sea vent Epsilonproteobacteria have never been isolated and characterized. Here, we successfully isolated a novel temperate phage, NrS-1, that infected a deep-sea vent chemolithoautotrophic isolate of Epsilonproteobacteria, Nitratiruptor sp. SB155-2, and its entire genome sequence was obtained and analyzed. The NrS-1 genome is linear, circularly permuted, and terminally redundant. The NrS-1 genome is 37,159 bp in length and contains 51 coding sequences. Five major structural proteins including major capsid protein and tape measure protein were identified by SDS-PAGE and mass spectrometry analysis. NrS-1 belongs to the family Siphoviridae, but its sequence and genomic organization are distinct from those of any other previously known Siphoviridae phages. Homologues of genes encoded in the NrS-1 genome were widely distributed among the genomes of diverse Epsilonproteobacteria. The distribution patterns had little relation to the evolutionary traits and ecological and physiological differentiation of the host epsilonproteobacterial species. The widespread occurrence of phage genes in diverse Epsilonproteobacteria supports early co-evolution between temperate phages and Epsilonproteobacteria prior to the divergence of their habitats and physiological adaptation. 相似文献
420.