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61.
Karina Motta Melo Ingrid Reale Alves Julio Cesar Pieczarka José Augusto de Oliveira David Cleusa Yoshiko Nagamachi Cesar Koppe Grisolia 《Genetics and molecular biology》2013,36(3):425-429
The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities. 相似文献
62.
Yoshiko Hanaoka Fumihiko Takebe Yoshinobu Nodasaka Isao Hara Hidetoshi Matsuyama Isao Yumoto 《PloS one》2013,8(10)
A psychrotolerant and H2O2-resistant bacterium, Exiguobacterium oxidotolerans T-2-2T, exhibits extraordinary H2O2 resistance and produces catalase not only intracellularly but also extracellularly. The intracellular and extracellular catalases exhibited the same enzymatic characteristics, that is, they exhibited the temperature-dependent activity characteristic of a cold-adapted enzyme, their heat stabilities were similar to those of mesophilic enzymes and very high catalytic intensity. In addition, catalase gene analysis indicated that the bacterium possessed the sole clade 1 catalase gene corresponding to intracellular catalase. Hence, intracellular catalase is secreted into the extracellular space. In addition to intracellular and extracellular catalases, the inner circumference of the cells showed the localization of catalase in the mid-stationary growth phase, which was observed by immunoelectron microscopy using an antibody against the intracellular catalase of the strain. The cells demonstrated higher catalase activity in the mid-stationary growth phase than in the exponential growth phase. The catalase localized in the inner circumference can be dissociated by treatment with Tween 60. Thus, the localized catalase is not tightly bound to the inner circumference of the cells and may play a role in the oxidative defense of the cells under low metabolic state. 相似文献
63.
Seiji Hayashizaki Shinobu Hirai Yumi Ito Yoshiko Honda Yosefu Arime Ichiro Sora Haruo Okado Tohru Kodama Masahiko Takada 《PloS one》2013,8(10)
Dopamine regulates the psychomotor stimulant activities of amphetamine-like substances in the brain. The effects of dopamine are mediated through five known dopamine receptor subtypes in mammals. The functional relevance of D5 dopamine receptors in the central nervous system is not well understood. To determine the functional relevance of D5 dopamine receptors, we created D5 dopamine receptor-deficient mice and then used these mice to assess the roles of D5 dopamine receptors in the behavioral response to methamphetamine. Interestingly, D5 dopamine receptor-deficient mice displayed increased ambulation in response to methamphetamine. Furthermore, dopamine transporter threonine phosphorylation levels, which regulate amphetamine-induced dopamine release, were elevated in D5 dopamine receptor-deficient mice. The increase in methamphetamine-induced locomotor activity was eliminated by pretreatment with the dopamine transporter blocker GBR12909. Taken together, these results suggest that dopamine transporter activity and threonine phosphorylation levels are regulated by D5 dopamine receptors. 相似文献
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66.
Hironobu Morinaga Seiichiro Kizaki Tomohiro Takenaka Shuhei Kanesato Yuta Sannohe Ryu Tashiro Hiroshi Sugiyama 《Bioorganic & medicinal chemistry》2013,21(2):466-469
5-Bromouracil (BrU) was incorporated into three types of synthetic RNA and the products of the photoirradiated BrU-containing RNAs were investigated using HPLC and MS analysis. The photoirradiation of r(GCABrUGC)2 and r(CGAABrUUGC)/r(GCAAUUCG) in A-form RNA produced the corresponding 2′-keto adenosine (ketoA) product at the 5′-neighboring nucleotide, such as r(GCketoAUGC) and r(CGAketoAUUGC), respectively. The photoirradiation of r(CGCGBrUGCG)/r(CmGCACmGCG) in Z-form RNA produced the 2′-keto guanosine (ketoG) product r(CGCketoGUGCG), whereas almost no products were observed from the photoirradiation of r(CGCGBrUGCG)/r(CmGCACmGCG) in A-form RNA. The present results indicate clearly that hydrogen (H) abstraction by the photochemically generated uracil-5-yl radical selectively occurs at the C2′ position to provide a 2′-keto RNA product. 相似文献
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68.
Kenji Seiwa Yoshiko Miwa Shigetoshi Akasaka Hiroshi Kanno Mizuki Tomita Tomoyuki Saitoh Naoto Ueno Megumi Kimura Yoichi Hasegawa Miki Konno Kazuhiko Masaka 《Ecological Research》2013,28(1):29-41
To evaluate the extent to which landslides affect community dynamics and consequent species diversity in a beech-dominated forest, differences in the composition and size structure of tree species were compared between landslide and adjacent stable (control) stands. Demography and changes in size were compared between the two stands over a 5-year period about 60 years after a landslide. In the control stand, replacement occurred even amongst late-successional species, with beech (Fagus crenata)—the most dominant species—increasing in relative abundance. In the landslide stand, very few large individuals of late-successional species occurred, whereas large individuals of early-successional species occurred only in the landslide stand. The traits indicate that the landslide strongly facilitated species diversity, not only by reducing the dominance of late-successional species, but also by promoting recruitment of early-successional species. However, new recruitment of early-successional species was inhibited in the landslide stand, although we observed succeeding regeneration and subsequent population growth of late-successional species there. As a result, the relative dominance of late-successional species increased with succession after the landslide, thus decreasing future species diversity. In beech-dominant forest landscapes in Japan that include communities with different developmental stages, the mosaic of serial stages may facilitate species diversity after a landslide. 相似文献
69.
Naoko Yuno Ohta Yoshiko Segawa Sonoe Fujii Yumiko Fujiwara Mariko Kuchiba Teruyoshi Matoba 《Bioscience, biotechnology, and biochemistry》2013,77(7):1747-1754
The effect of various reagents on the formation and stability of heat-induced gels of sesame 13S globulins were investigated. Electrostatic interaction, the hydrophobic bond and the disulfide bond were important for forming the network structure of gels, and the hydrogen bond also had an influence on the formation of the gel. Hydrophobic bonds mainly contributed to the stability of the gel. Subunit analyses of the proteins solubilized from the gels showed the presence of a free acidic subunit (AS) and basic subunit (BS), a polymer of AS, a dimer of BS and the dimer of a fragment from AS or BS. From the results, sulfhydryl-disulfide exchange reactions during gelation are suggested. 相似文献
70.
Koshi Arai Tetsu Ando Sadahiro Tatsuki Kenji Usui Yoshiko Ohguchi Matsuo Kurihara 《Bioscience, biotechnology, and biochemistry》2013,77(12):3165-3168
Lipoxygenase-3, the major component of the enzyme in rice grain, was purified 2980-fold with a yield of 7% from embryos. The purified enzyme had a specific activity of 280 μmol O2 formed/min per mg protein. This enzyme was inactivated by SH compounds, such as cysteine and glutathione. The inactivation was prevented by the addition of catalase or replacement of the air by N2 gas. These two treatments were also effective for the stable storage of the purified enzyme. The molecular weights measured by sodium dodecyl sulfate gel and gradient gel electrophoresis were 93,000 and 89,000, respectively, indicating that the enzyme is a single polypeptide chain. The purified enzyme contained 0.73 Fe atom per molecule. The absorption spectrum suggested that the enzyme is a non-heme iron protein. Some similarities in amino-acid composition were observed between rice, soybean, and pea lipoxygenases. The purified enzyme specifically produced 9-d-hydroperoxy-10,12(E,Z)-octadecadienoic acid when linoleic acid was used as a substrate. 相似文献