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131.
Ichiro Tayasu Toshio Nakamura Hirotaka Oda Fujio Hyodo Yoko Takematsu Takuya Abe 《Ecological Research》2002,17(2):195-206
Stable (13C and 15N) and radio- (14C, 137Cs and 210Pb) isotopes were determined for termites that
have been sampled from a dry evergreen forest in Thailand. A wood-feeding termite, Microcerotermes crassus, was separated from soil-feeders: Termes propinquus, Termes comis and Dicuspiditermes makhamensis by 13C and 15N values. The Termes group in Thailand had less diverse values in 13C and 15N than those in Australia, where the feeding habits of the Termes group are more diverse. Other soil-feeding termites produced similar 13C values, but a larger range in 15N values. 14C-percent modern carbon (pMC) values suggest that the soil-feeding termites used younger carbon than the wood-feeding termites, and this was consistent with the termites from Cameroon, central Africa. Values of 13C and 14C-pMC indicate that surface soil was used by a soil-feeding termite, D. makhamensis, in making the nest mounds, and deeper soil (10–30 cm) by a fungus-growing termite, Macrotermes carbonarius. 210Pb and 137Cs were scarcely incorporated into the termites, although 214Pb was recovered from the workers. The results suggest that stable- and radioisotopes are useful in the study of detritivorous animals, organic matter decomposition and ecosystem engineering.Takuya Abe - deceased. 相似文献
132.
Seko T Kato M Kohno H Ono S Hashimura K Takenobu Y Takimizu H Nakai K Maegawa H Katsube N Toda M 《Bioorganic & medicinal chemistry letters》2002,12(17):2267-2269
This study was performed to determine the structure-activity relationships (SAR) of L-cysteine based N-type calcium channel blockers. Basic nitrogen was introduced into the C-terminal lipophilic moiety of L-cysteine with a view toward improvement of its physicochemical properties. L-Cysteine derivative 9 was found to be a potent and selective N-type calcium channel blocker with IC(50) of 0.33 microM in calcium influx assay using IMR-32 cells and was 15-fold selective for N-type calcium channels over L-type channels. Compound 9 showed improved oral analgesic efficacy in the rat formalin induced pain model and the rat chronic constriction injury (CCI) model, which is one of the most reliable models of chronic neuropathic pain, without any significant effect on blood pressure or neurological behavior. 相似文献
133.
Matsumoto K Tsukahara Y Uemura T Tsunoda K Kume H Kawasaki S Tadano J Matsuya T 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2002,773(2):135-142
A new fluorescent europium chelate labeling reagent, 5-(4"-chlorosulfo-1',1"-diphenyl-4'-yl)-1,1,1,2,2-pentafluoro-3,5-pentanedione (CDPP), was synthesized for the time-resolved fluorometric detection of HPLC. The label can be directly bound to amino or phenolic hydroxyl groups of analytes with its chlorosulfonyl group, and the labeled analytes are separated on a HPLC column. After separation, EuCl(3), TOPO (tri-n-octylphosphine oxide), and Triton X-100 were added by post-column introduction to the eluent, and the fluorescence of the europium chelate was measured with the time-resolved fluorometric detector. Estrone (E1), 17beta-estradiol (E2), ethynylestradiol (EE2) and estriol (E3) were measured with the detection limits of 0.65, 0.65, 0.65 and 0.60 ng/ml, respectively. The recovery for river water samples was in the range of 86.0-105.1% with the RSD of 1.9-5.8%. The method was applied to the analysis of a river water sample and estrone (E1) was determined to be 2.1 ng/l. The results and processing have been compared with those of a GC-MS method and a high degree of correlation (r> or =0.98) was observed. 相似文献
134.
Recent progress and problems in animal cloning 总被引:4,自引:0,他引:4
It is remarkable that mammalian somatic cell nuclei can form whole individuals if they are transferred to enucleated oocytes. Advancements in nuclear transfer technology can now be applied for genetic improvement and increase of farm animals, rescue of endangered species, and assisted reproduction and tissue engineering in humans. Since July 1998, more than 200 calves have been produced by nuclear transfer of somatic cell nuclei in Japan, but half of them were stillborn or died within several months of parturition. Morphologic abnormalities have also been observed in cloned calves and embryonic stem cell-derived mice. In this review, we discuss the present situation and problems with animal cloning and the possibility for its application to human medicine. 相似文献
135.
Isolation and identification of EG-VEGF/prokineticins as cognate ligands for two orphan G-protein-coupled receptors 总被引:8,自引:0,他引:8
Masuda Y Takatsu Y Terao Y Kumano S Ishibashi Y Suenaga M Abe M Fukusumi S Watanabe T Shintani Y Yamada T Hinuma S Inatomi N Ohtaki T Onda H Fujino M 《Biochemical and biophysical research communications》2002,293(1):396-402
Endocrine gland-derived vascular endothelial growth factor (EG-VEGF, identical to prokineticin 1) is a novel peptide recently identified as a selective mitogen for endocrine gland endothelial cells. The present study demonstrates that EG-VEGF/prokineticin 1 and a peptide closely related to EG-VEGF, prokineticin 2, are cognate ligands of two orphan G-protein-coupled receptors designated ZAQ (=EG-VEGF/PK-R1) and I5E (=EG-VEGF/PK-R2). EG-VEGF/prokineticin 1 and prokineticin 2 induced a transient increase in intracellular calcium ion concentration ([Ca(2+)](i)) with nanomolar potency in Chinese hamster ovary (CHO) cells expressing EG-VEGF/PK-R1 and -R2 and bind to these cells with high affinity and with different receptor selectivity. EG-VEGF/prokineticins provoke rapid phosphorylation of p44/42 MAP kinase and DNA synthesis in the bovine adrenal capillary endothelial cells (BACE). The mRNAs of both EG-VEGF/PK-R1 and -R2 were expressed in BACE. The identification of the receptors for EG-VEGF/prokineticins may provide a novel molecular basis for the regulation of angiogenesis in endocrine glands. 相似文献
136.
Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W. F. Wight, respectively, during mulching to investigate the properties and estimate changes in lignin composition and content. Since the Klason lignin residue originated from components highly resistant to degradation by acid, the methoxyl content of Klason residue was used to estimate the lignin content of leaf litter. Quantitative analysis of presumed lignin-derived fragments, by use of alkaline nitrobenzene oxidation and ozonation methods, suggested that the estimated lignin content approximates that of the real lignin content of leaves, which is greatly overestimated by the Klason procedure. The estimated lignin contents ranged from 3.9 to 10.0% while the Klason lignan residue varied from 37.1 to 46.7% in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure. 相似文献
137.
Kawakami T Nagata T Muraguchi A Nishimura T 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,787(1):223-229
Apoptosis is an essential process for selection of T lymphocytes specific for foreign antigen in the process of mammalian thymus maturation. Proteomics, a comprehensive study of proteins expressed in a cell, will facilitate the systematic analysis of protein molecules related to such a complicated biological system. Protein expression profiles including information about protein signatures, localization and their quantitative changes with extracellular stimulations are extremely useful to construct intracellular pathway models resulting in the apoptotic cell death. 相似文献
138.
Interaction between leukemic-cell VLA-4 and stromal fibronectin is a decisive factor for minimal residual disease of acute myelogenous leukemia 总被引:27,自引:0,他引:27
Matsunaga T Takemoto N Sato T Takimoto R Tanaka I Fujimi A Akiyama T Kuroda H Kawano Y Kobune M Kato J Hirayama Y Sakamaki S Kohda K Miyake K Niitsu Y 《Nature medicine》2003,9(9):1158-1165
Bone-marrow minimal residual disease (MRD) causes relapse after chemotherapy in patients with acute myelogenous leukemia (AML). We postulate that the drug resistance is induced by the attachment of very late antigen (VLA)-4 on leukemic cells to fibronectin on bone-marrow stromal cells. We found that VLA-4-positive cells acquired resistance to anoikis (loss of anchorage) or drug-induced apoptosis through the phosphatidylinositol-3-kinase (PI-3K)/AKT/Bcl-2 signaling pathway, which is activated by the interaction of VLA-4 and fibronectin. This resistance was negated by VLA-4-specific antibodies. In a mouse model of MRD, we achieved a 100% survival rate by combining VLA-4-specific antibodies and cytosine arabinoside (AraC), whereas AraC alone prolonged survival only slightly. In addition, overall survival at 5 years was 100% for 10 VLA-4-negative patients and 44.4% for 15 VLA-4-positive patients. Thus, the interaction between VLA-4 on leukemic cells and fibronectin on stromal cells may be crucial in bone marrow MRD and AML prognosis. 相似文献
139.
Chiba T Li YH Yamane T Ogikubo O Fukuoka M Arai R Takahashi S Ohtsuka T Ohkubo I Matsui N 《Peptides》2003,24(5):773-778
In order to find the most effective antagonist for dipeptidyl peptidase III degrading enkephalin, we synthesized hemorphin-like pentapeptides with aliphatic or aromatic amino acids at the N-termini, such as VVYPW, LVYPW, IVYPW, YVYPW, FVYPW and WVYPW. Among those pentapeptides, IVYPW and WVYPW showed the strongest inhibitory activity toward rDPP III. The K(i) values of IVYPW and WVYPW were 0.100+/-0.011 and 0.126+/-0.015 microM (mean+/-S.E.), respectively. The order of K(i) values was Ile> or =Trp>Phe> or =Tyr>Leu>Ala>Val>Ser>Gly. rDPP III activity is inhibited in a non-competitive manner by these peptides. The peptide VYPW did not inhibit rDPP III activity, but the sequence is essential for the expression of inhibitory activity. 相似文献
140.
Masahiko?HirataEmail author Mihoko?Nakagawa Harumi?Funakoshi Takuya?Iwamoto Waka?Otozu Daisuke?Kiyota Shirou?Kuroki Kiichi?Fukuyama 《Journal of Ethology》2003,21(2):161-168
Distance between dam and offspring (1–121 days old) in a herd of Japanese Black cattle (Bos taurus) grazing a tropical grass (Paspalum notatum) pasture (1.5 ha) was investigated during 7-h grazing periods over grazing seasons from May (spring) to October (autumn).
The mother–young distance was not constant throughout the grazing period, repeatedly increasing and decreasing. Although significant
periodicity was always detected in the mother–young distance, there was no consistent dominant cycle, indicating the complexity
of the within-day pattern of mother–young distance. The mean mother–young distance over the grazing period increased as a
calf aged, reaching a plateau at an age of about 33 days. The mean distance of a calf from its mother was usually shorter
than that from a non-mother cow, with the difference between the mean distances decreasing sharply until a calf became about
35 days old. The results and literature show that mutual independence of mother and young rapidly develops in the first 30–50 days
after parturition.
Electronic Publication 相似文献