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71.
72.
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
73.
Takashi Matsumoto Daisuke Yoshida Shigenobu Mizusaki Hideo Tomita Koichi Koshimizu 《Bioscience, biotechnology, and biochemistry》2013,77(4):861-864
The mutagenic activities of quinoline, isoquinoline, phenanthridine, benzo(f)quinoline, benzo(h)quinoline and their α-amino derivatives were compared in relation to the effect of structural changes using the Salmonella typhimurium test system. All mutagenic compounds tested require the liver microsomal fraction for their mutagenic activity. Phenanthridine, two benzoquinolines and quinoline were mutagenic. α-Amination of two benzoquinolines and quinoline resulted to increase their mutagenic activity intensively. Addition of a benzene ring to the benzene moiety of 2-aminoquinoline, so that two carbon atoms are shared, affected distinctly the increase in the mutagenic activity. The co-existence of benzoquinoline series with 2-aminobenzo(f)quinoline showed the clear synergistic action. 相似文献
74.
Mitsuru Ando Masayuki Nakagawa Toshiie Nakamura Kazuo Tomita 《Bioscience, biotechnology, and biochemistry》2013,77(4):803-809
Excretion, distribution and metabolism of the insecticide, Isoxathion, administered orally in male Wistar-strain rats, were investigated with a carbon-14 labeled chemical. During 96 hr, approximately 85% and 14% of the total radioactivity were excreted in the urine and feces. Distribution of isoxathion after oral administration in the rats was investigated by means of whole-body autoradiographic technique and measurement of radioactivity in the tissues. At least eleven radioactive metabolites were detected, four of which were structurally determined. They were 3-hydroxy-5-phenylisoxazole, 3-(β-d-glucopyranuronosyloxy)-5-phenylisoxazole, 5-phenyl-3-isoxazolyl sulfate and hippuric acid. 相似文献
75.
Fusao Tomita Hirofumi Nakano Haruo Honda Takeo Suzuki 《Bioscience, biotechnology, and biochemistry》2013,77(11):2183-2188
The isolation of chloramphenicol resistant strains from Corynebacterium hydrocarboclastus KY 4339 (rough type) was examined to seek a good source of corynecins (analogs of chloramphenicol). Various mutants resistant to chloramphenicol were isolated in the range from 50 to 1000 µg/ml by adaptation or induced mutagenesis by N-methyl-N′-nitro-N-nitro-soguanidine. Productivities of mutants related apparently to the degree of resistance from 50 to 500 µg/ml. Highly resistant mutants capable of growing in the presence of 1000 µg of chloramphenicol per ml showed decreased productivity which might be related to their lower growth rate in the fermentation medium.Further attempts to derive resistant mutants to structural analogs of aromatic amino acids resulted in only a slight improvement of productivity, indicating that aromatic amino acids might play minor regulatory roles in corynecins synthesis.The increase in productivity of corynecins by the best strain was about 4.5 fold of the parental strain. 相似文献
76.
Environmental perturbations influence telomere dynamics in long-lived birds in their natural habitat
Telomeres are regarded as markers of biological or cellular ageing because they shorten with the degree of stress exposure. Accordingly, telomere lengths should show different rates of change when animals are faced with different intensities of environmental challenges. However, a relationship between telomere length and the environment has not yet been tested within a natural setting. Here, we report longitudinal telomere dynamics in free-living, black-tailed gulls (Larus crassirostris) through the recapture of birds of a known age over 2–5 consecutive years. The rate of change in telomere lengths differed with respect to year but not sex or age. The years when gulls showed stable telomere lengths or increases in telomere lengths (from 2009 to 2010) and decreases in telomere lengths (from 2010 to 2011) were characterized by El Niño and the Great Japan Earthquake, respectively. Both events are suspected to have had long-lasting effects on food availability and/or weather conditions. Thus, our findings that telomere dynamics in long-lived birds are influenced by dramatic changes in environmental conditions highlight the importance of environmental fluctuations in affecting stress and lifespan. 相似文献
77.
The intrinsic optimum temperature for the development of ectotherms is one of the most important factors not only for their physiological processes but also for ecological and evolutional processes. The Sharpe–Schoolfield–Ikemoto (SSI) model succeeded in defining the temperature that can thermodynamically meet the condition that at a particular temperature the probability of an active enzyme reaching its maximum activity is realized. Previously, an algorithm was developed by Ikemoto (Tropical malaria does not mean hot environments. Journal of Medical Entomology, 45, 963–969) to estimate model parameters, but that program was computationally very time consuming. Now, investigators can use the SSI model more easily because a full automatic computer program was designed by Shi et al. (A modified program for estimating the parameters of the SSI model. Environmental Entomology, 40, 462–469). However, the statistical significance of the point estimate of the intrinsic optimum temperature for each ectotherm has not yet been determined. Here, we provided a new method for calculating the confidence interval of the estimated intrinsic optimum temperature by modifying the approximate bootstrap confidence intervals method. For this purpose, it was necessary to develop a new program for a faster estimation of the parameters in the SSI model, which we have also done. 相似文献
78.
Koji Sugiyama Mami Kawamura Hisato Tomita Shizuo Katamoto 《Journal of physiological anthropology》2013,32(1):2
The purpose of this study was to characterize responses in oxygen uptake (
), heart rate (HR), perceived exertion (OMNI scale) and integrated electromyogram (iEMG) readings during incremental Nordic walking (NW) and level walking (LW) on a treadmill. Ten healthy adults (four men, six women), who regularly engaged in physical activity in their daily lives, were enrolled in the study. All subjects were familiar with NW. Each subject began walking at 60 m/min for 3 minutes, with incremental increases of 10 m/min every 2 minutes up to 120 m/min
,
and HR were measured every 30 seconds, and the OMNI scale was used during the final 15 seconds of each exercise. EMG readings were recorded from the triceps brachii, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior muscles.
was significantly higher during NW than during LW, with the exception of the speed of 70 m/min (P < 0.01).
and HR were higher during NW than LW at all walking speeds (P < 0.05 to 0.001). OMNI scale of the upper extremities was significantly higher during NW than during LW at all speeds (P < 0.05). Furthermore, the iEMG reading for the VL was lower during NW than during LW at all walking speeds, while the iEMG reading for the BF and GA muscles were significantly lower during NW than LW at some speeds. These data suggest that the use of poles in NW attenuates muscle activity in the lower extremities during the stance and push-off phases, and decreases that of the lower extremities and increase energy expenditure of the upper body and respiratory system at certain walking speeds. 相似文献
79.
Issei Ueda Shingo Kakeda Keita Watanabe Reiji Yoshimura Taro Kishi Osamu Abe Satoru Ide Junji Moriya Asuka Katsuki Hikaru Hori Nakao Iwata Jun Nakamura Yukunori Korogi 《PloS one》2016,11(3)