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排序方式: 共有260条查询结果,搜索用时 21 毫秒
1.
Takakazu Yumoto 《Ecological Research》1987,2(2):133-145
Animal pollination in a warm temperate evergreen broad-leaved forest was observed on Yaku-shima Island, south of Kyushu, Japan.
Three groups of plants were categorized: canopy-flowering tree species, understory-flowering tree species, and climber and
epiphyte species. Each of these formed different pollination systems. The canopy-flowering tree species had shallow, dish-shaped
flowers and utilized various types of opportunistic pollinators. Most of the climber and epiphyte species had deep, tube-shaped
flowers and specialized pollinators, although some climber species which bloomed in the canopy especially in winter, had opportunistic
pollinators. The understory-flowering tree species had large dish- or funnel-shaped flowers and endothermic pollinators able
to tolerate the dark and cold conditions under the canopy. The individual trees of canopy-flowering tree species produced
large numbers of flowers simultaneously (mass-flowering) and had a well synchronized flowering period. Each canopy-flowering
tree species segregated its flowering time from those of the anothers. Climber and epiphyte species and most of the understory-flowering
tree species produced small numbers of flowers sequentially (extended flowering) and showed a long flowering period. 相似文献
2.
K Ogawa M Tashima Y Yumoto T Okuda H Sawada M Okuma Y Maruyama 《Nucleic acids research》1990,18(23):7169
3.
Setsuzo Tada Katsuya Gomi Katsuhiko Kitamoto Kojiro Takahashi Gakuzo Tamura Shodo Hara 《Molecular & general genetics : MGG》1991,229(2):301-306
Summary Northern blot analysis of glucose-grown and starch-grown mycelia of Aspergillus oryzae R11340 was conducted using the cloned Taka-amylase A (TAA) gene as a probe. The amount of mRNA homologous to the TAA gene was increased when this fungus was grown with starch as a sole carbon source. In order to analyze the induction mechanism, we inserted the Escherichia coli uidA gene encoding -glucuronidase (GUS) downstream of the TAA promoter and introduced the resultant fusion gene into the A. oryzae genome. Production of a functional GUS protein was induced by starch, but not by glucose. When the effects of various sugars on expression of the fusion gene were examined, the results suggested that the expression of the fusion gene was under control of the TAA gene promoter. 相似文献
4.
Makoto Kato Tamiji Inoue Abang Abdul Hamid Teruyoshi Nagamitsu Mahamud Ben Merdek Abdul Rahman Nona Takao Itino Seiki Yamane Takakazu Yumoto 《Population Ecology》1995,37(1):59-79
Nocturnal flying insects were collected monthly for 13 months using ultra violet light-traps set at various vertical levels in a weakly-seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non-random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule-feeders and in phloem-feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem-feeders, seed-feeders, wood-borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem-, ovule-, seed-, root-, fungal-feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level. 相似文献
5.
Juichi Yamagiwa Ndunda Mwanza Takakazu Yumoto Tamaki Maruhashi 《Primates; journal of primatology》1994,35(1):1-14
Details are presented of the composition of the diet of eastern lowland gorillas, derived mainly from a study of their fresh
trails and fecal analysis, during the course of an entire year in the tropical lowland forests of the Itebero region, Zaire.
Gorillas ate 194 plant foods from 121 species and 45 families. They consumed 48 species of fruits; and 89% of fecal samples
contained fruit seeds, but fruits were a relatively small part (25%) of the total number of food items. The composition of
their diet changed seasonally. When consumption of fruit decreased in the long rainy and the long dry seasons, the gorillas
ate, in addition to Zingiberaceae and Marantaceae, many kinds of leaf and bark, which may be an important buffer against the
shortage of fruits. Gorillas also fed regularly on ants (Ponerinae), and the frequency of consumption showed small seasonal
variations. From a comparison of diet composition, eastern lowland gorillas appeared to be intermediate between the other
two subspecies. The choice of food showed differences in preference of fruits and insects between subspecies and may reflect
high similarities within subspecies in lowland and montane forests. 相似文献
6.
Studies on aspartase VIII. Protease-mediated activation: comparative survey of protease specificity for activation and peptide cleavage 总被引:1,自引:0,他引:1
The active species of aspartase from Escherichia coli is further 3-5 fold activated upon limited proteolysis with trypsin releasing carboxy-terminal peptides as reported previously (N. Yumoto, M. Tokushige, and R. Hayashi. Biochim. Biophys. Acta, 616, 319 (1980) ). Survey of the protease specificity for the activation revealed that subtilisin BPN' and several other proteases having far broader substrate specificity than trypsin also activated the enzyme. The results of sequence analyses revealed that subtilisin BPN' cleaved mainly the serylarginine bond near the carboxy-terminal and released an octapeptide, while trypsin cleaved mainly the arginyltyrosine bond which is just next to the subtilisin cleavage site. These results suggest that the protease-mediated activation does not necessarily require a site-specific peptidyl cleavage, but the cleavage of any bond within a certain region centered at arginine, the eighth residue from the carboxy-terminal, is sufficient. 相似文献
7.
The biodegradative threonine deaminase from Escherichia coli is activated allosterically by AMP. To identify the residues interacting with the phosphate group of AMP at the binding site, we used the affinity labeling reagent, adenosine diphosphopyridoxal (AP2-PL). In the absence of AMP, the enzyme formed the Schiff base with AP2-PL and Scatchard plot analysis showed a biphasic pattern, the respective Kd values for the high- and low-affinity binding phases being 20 and 110 microM. The former value is comparable to the Kd value of the enzyme for AMP. In the presence of AMP, the Schiff base formation was greatly reduced. Although the maximal activating effect of adenosine diphosphopyridoxine, a non-reactive derivative of AP2-PL, was about 13% of that of AMP, the half-saturation concentration was almost the same. These findings suggest that AP2-PL specifically labeled the lysyl residue(s) at the AMP-binding site of the enzyme. To identify the labeled residue(s), we reduced the modified enzyme with sodium borohydride, then cleaved it with cyanogen bromide and Achromobacter lyticus protease I. Reverse-phase HPLC was used to isolate two labeled peptides from the digest. Their amino acid compositions and sequences showed that Lys-111 and Lys-113 were labeled. We conclude that these two lysyl residues are located around the phosphate group of AMP at the allosteric regulation site of the enzyme. 相似文献
8.
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
9.
Tadashi Shimamura Satoe Iijima Mitsuhiro Hirayama Masato Iwashita Shigeru Akiyama Yuichi Takaku Sakae Yumoto 《Journal of trace elements in medicine and biology》2013,27(4):286-294
The concentrations of 22 major and trace elements in livers from rats aging from 5 to 113 weeks old were determined. The rats investigated were the same rats previously reported with respect to 29 elements in bones (femur) and 26 elements in kidneys. The samples were decomposed with high-purity nitric acid and hydrogen peroxide. Seven elements (Na, Mg, P, K, Ca, Fe and Zn) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and 15 elements (Mn, Co, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Pb and Bi) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of variance (ANOVA) for age variations indicated that the concentrations of many elements, such as Mg, P, K, Mn, Fe, Cu, Zn, Sr, Mo and Cd, were almost constant across the ages of the rats with the exception of 5 weeks old (p > 0.05). Arsenic, Pb and Bi showed significant increasing trends, while Na and Co showed decreasing trends (p < 0.01). Selenium showed a decreasing trend except at the initial stage of 5–9 weeks old. Calcium, Rb, Sn, Sb, Cs and Ba showed significant age-related variations, but their patterns were not monotonic. The liver clearly contrasts with the kidneys, in which many elements showed significant age-related variations with increasing trends. The concentration ranges of Mg, P, K, Mn, Cu, Zn, and Mo were controlled within 15% across all ages of rats. The homeostasis of the aforementioned elements may be well established in the liver. The toxic elements, such as Cd, Pb and Bi, showed a narrow concentration range among age-matched rats. 相似文献
10.
Yasuko Sekita Keiji Murakami Hiromichi Yumoto Hiroyuki Mizuguchi Takashi Amoh Satoshi Ogino 《Bioscience, biotechnology, and biochemistry》2016,80(6):1205-1213
Houttuynia cordata (HC) has been commonly used as many traditional remedies in local areas of Japan. Although many pharmacological activities of HC have been reported, the mechanism underlying the effect of HC remains unknown. We conducted the interview survey in Japan to verify how HC was actually used. The interview survey revealed that HC poultice (HCP) prepared from smothering fresh leaves of HC was most frequently used for the treatment of purulent skin diseases including furuncle and carbuncle with high effectiveness. Ethanol extract of HCP (eHCP) showed anti-bacterial effects against methicillin-resistant Staphylococcus aureus (MRSA), and showed an anti-biofilm activity against MRSA. eHCP showed dose-dependent inhibition of S. aureus lipoteichoic acid (LTA)-induced interleukin-8 and CCL20 production in human keratinocyte without any cytotoxicity. These results suggest that HCP is effective for skin abscess and its underlying mechanism might be the complicated multiple activities for both bacteria and host cells. 相似文献