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71.
Ueno S Kashimoto T Susa N Shiho K Seki T Ito N Takeda-Homma S Nishimura Y Sugiyama M 《Free radical research》2007,41(11):1246-1252
Hydroxyl radical (·OH) generation in the kidney of mice treated with ferric nitrilotriacetate (Fe-NTA) or potassium bromate (KBrO3) in vivo was estimated by the salicylate hydroxylation method, using the optimal experimental conditions we recently reported. Induction of DNA lesions and lipid peroxidation in the kidney by these nephrotoxic compounds was also examined. The salicylate hydroxylation method revealed significant increases in the ·OH generation after injection of Fe-NTA or KBrO3 in the kidneys. A significant increase in 8-hydroxy-2'-deoxyguanosine in nuclei of the kidney was detected only in the KBrO3 treated mice, while the comet assay showed that the Fe-NTA and KBrO3 treatments both resulted in significant increases in DNA breakage in the kidney. With respect to lipid peroxidation, the Fe-NTA treatment enhanced lipid peroxidation and ESR signals of the alkylperoxy radical adduct. These DNA breaks and lipid peroxidation mediated by ·OH were diminished by pre-treatment with salicylate in vivo. These results clearly demonstrated the usefulness of the salicylate hydroxylation method as well as the comet assay in estimating the involvement of ·OH generation in cellular injury induced by chemicals in vivo. 相似文献
72.
This study describes Homevaleia gouldii H. Nishida, Pigg, Kudo et Rigby gen. et sp. nov., an ovule-bearing glossopterid organ, based on a combination of recently
collected permineralized specimens from the Late Permian Homevale Station locality in the Bowen Basin of Queensland, Australia,
and on previously studied material from the 1977 Gould and Delevoryas study. Homevaleia, which resembles the compression–impression genus Dictyopteridium, is an inrolled megasporophyll with a distinct keel that bears numerous (over 70) stalked ovules on its adaxial surface.
Ovules are small, oval, with an elaborate mesh-like structure that is developed from the outermost integumentary layers. Specimens
interpreted as representing different developmental stages show there is an apparent interrelationship between megagametophyte
development and the opening of the surrounding fertile structure for pollination. Together, new information provided by this
material enables better understanding of glossopterid reproductive structure and its function in one distinctive form. 相似文献
73.
Under laboratory conditions, spores of ectomycorrhizal fungi usually germinate very poorly or not at all. In a previous study,
we showed that spores of the ectomycorrhizal fungus Suillus bovinus germinated through the combination of activated charcoal treatment of media and co-culture with seedlings of Pinus densiflora, which suggested that some substances contained in root exudates induced the germination. Among the compounds reported from
root exudates, flavonoids have been elucidated to play various and substantial roles in plant–microbe interactions; we therefore
investigated the effects of flavonoids on basidiospore germination of S. bovinus by the diffusion gradient assay on water agar plates pretreated with charcoal powder. Seven out of the 11 flavonoids tested,
hesperidin, morin, rutin, quercitrin, naringenin, genistein, and chrysin, had greater effects than controls, whereas flavone,
biochanin A, luteolin, and quercetin showed no positive effects. The effective concentration presumably corresponded to several
micromolar levels, which was equivalent to those effective for pollen development, nod gene induction, and spore germination of F. solani f. sp. pisi and AM fungi. The results suggest that flavonoids play a role as signaling molecules in symbiotic relationships between woody
plants and ectomycorrhizal fungi. 相似文献
74.
75.
Kensuke Nakata Yusuke Shigemiya 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(4):954-963
Animal body coloration serves several functions such as thermoregulation, camouflage, aposematism, and intraspecific communication. In some orb‐web spiders, bright and conspicuous body colours are used to attract prey. On the other hand, there are other species whose body colour does not attract prey. Using a spider species showing individual body‐colour variation, the present study aimed to determine whether or not the variation in body colour shows a correlation with predation rates. We studied the orb‐web spider (Cyclosa argenteoalba) using both field observations and T‐maze experiments, in which the prey were exposed to differently coloured spiders. Cyclosa argenteoalba has silver‐ and black‐coloured areas on its dorsal abdomen, with the ratio of these two colours varying continuously among individuals. The bright and conspicuous silver area reflects ultraviolet light. Results of both field observations and colour choice experiments using Drosophila flies as prey showed that darker spiders have a greater chance of capturing prey than silver spiders. This indicates that body‐colour variation affects predation success among individuals and that the bright silver colour does not function to attract prey in C. argenteoalba. 相似文献
76.
77.
Kurata H Otsuki K Kusumi K Kurono M Terakado M Seko T Mizuno H Ono T Hagiya H Minami M Nakade S Habashita H 《Bioorganic & medicinal chemistry letters》2011,21(5):1390-1393
Structure-activity relationship of sphingosine-1-phosphate receptor agonist was examined. In terms of reducing the flexibility of molecule, hit compound 1 was modified to improve S1P1 agonistic activity as well as selectivity over S1P3 agonistic activity. Novel S1P agonists with cinnamyl scaffold or 1,2,5,6-tetrahydropyridine scaffold were identified. 相似文献
78.
Saito T Obitsu T Kondo T Matsui T Nagao Y Kusumi K Matsumura N Ueno S Kishi A Katsumata S Kagamiishi Y Nakai H Toda M 《Bioorganic & medicinal chemistry》2011,19(18):5432-5445
To identify an orally active corticotropin-releasing factor 1 receptor antagonist, a series of 6,7-dihydro-5H-cyclopenta[d]pyrazolo[1,5-a]pyrimidines and their derivatives were designed, synthesized and evaluated. An in vitro study followed by in vivo and pharmacokinetic studies of these heterotricyclic compounds led us to the discovery of an orally active CRF1 receptor antagonist. The results of a structure-activity relationship study are presented. 相似文献
79.
We report the synthesis and characterization of the arsonic acid-presenting superparamagnetic iron oxide (SPIO). We used arsonoacetic acid as the ligand for SPIOs in aqueous media. The surface modification of the SPIOs was accomplished via the ligand exchange from undecanoic acid to the carboxyl moiety of arsonoacetic acid. Consequently, the well-dispersed arsonic acid-presenting SPIOs in water were obtained. We found that the dispersion state of the arsonic acid-presenting SPIOs can be sharply regulated by pH changes in the biological significant region. The well dispersion state of the arsonic acid-presenting SPIOs can be maintained at the neutral pH region. In contrast, the arsonic acid-presenting SPIOs can sensitively form the aggregation below pH 6.1. Moreover, these dispersion states can be controlled reversibly by the pH alteration in the narrow region. 相似文献
80.