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291.
Yukiko Makino Shigeru Ohta Yoshikazu Tasaki Osamu Tachikawa Masaki Kashiwasake Masaaki Hirobe 《Journal of neurochemistry》1990,55(3):963-970
Serotonin binding protein (SBP) is a vesicular protein found in neurectoderm-derived cells that store 5-hydroxytryptamine (5-HT, serotonin), such as central and peripheral serotonergic neurons and paraneurons (parafollicular cells of the thyroid). 5-HT is stored as a complex with SBP in vivo. Two forms of the protein are found. These differ in molecular mass: one is 45 kDa and the other 56 kDa. It has been suggested that the 56-kDa form of SBP may be the precursor of the 45-kDa form. To study the relationship between these two proteins, we have used a covalently bound radiolabeled probe to analyze their binding domains. A photoaffinity reagent, N-(4-azido-2-nitrophenyl)-5-hydroxytryptamine (NAP-5-HT), was synthesized and characterized by nuclear magnetic resonance spectroscopy, mass spectra, and UV-visible absorption spectra. A 1 M excess of NAP-5-HT inhibited the binding of [3H]5-HT to SBP by 50%. NAP[3H]5-HT was also synthesized and attached to both high- and low-affinity binding sites on both forms of SBP. The high-affinity constants for 45-kDa and 56-kDa proteins were 0.8 nM and 0.02 nM, respectively, whereas the low-affinity constants were 0.3 microM and 0.15 microM. When the high-affinity site of partially purified SBP was photoaffinity-labeled with the reagent, two covalently labeled proteins (45 kDa and 56 kDa) were found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Inhibition of the labeling of both proteins by 50% was observed in the presence of a 15-fold molar excess of 5-HT.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
292.
4-Hydroxytetrahydroisoquinoline (4OH-TIQ) was detected as a metabolite of a possible parkinsonism-inducing substance, tetrahydroisoquinoline (TIQ), in rat liver microsomes and rat urine. Urinary excretion of 4OH-TIQ was significantly reduced in female DA rat, an animal model of a poor debrisoquine metabolizer. The female DA rat also showed significantly higher brain accumulation of TIQ. These results suggest that the metabolic detoxication process is depressed and TIQ accumulation in the brain is enhanced in a poor debrisoquine metabolizer, which may be one possible explanation for poor debrisoquine metabolizers being susceptible to Parkinson's disease. 相似文献
293.
Manabu Suno Takayuki Kunisawa Akio Yamagishi Takashi Ono Joe Yamamoto Takehiro Yamada Yoshikazu Tasaki Keiko Shimizu Hiroshi Iwasaki Kazuo Matsubara 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(16-17):1705-1708
Landiolol hydrochloride, a new adrenergic β1-selective antagonist having an ultra-short half-life, is used to prevent tachyarrhythmia during surgery. Since landiolol is thought to be rapidly hydrolyzed to an inactivate metabolite by esterases, quantification of the drug concentration in the blood is impractical. The landiolol concentration in blood was halved within 5 min after blood sampling. This degradation was effectively prevented by pre-treatment with neostigmine (100 μg) in the sampling tube, but not by EDTA pre-treatment, indicating that landiolol could be metabolized by pseudocholinesterase in plasma. After the one-step solid-phase extraction, fluorescence detection of landiolol reduced chromatographic background signals and then improved assay sensitivity to the lower limit of 10 ng/ml in blood; this reproducible approach yielded coefficient variation of less than 6%. The blood concentration-time profile of landiolol hydrochloride in patients of the present investigation afforded more practical assessment than previously reported studies, thus improving accuracy and facilitating detailed pharmacokinetic study in relation to the pharmacological action of drug. 相似文献
294.
Yamahata C Collard D Takekawa T Kumemura M Hashiguchi G Fujita H 《Biophysical journal》2008,94(1):63-70
The study of the electrical properties of DNA has aroused increasing interest since the last decade. So far, controversial arguments have been put forward to explain the electrical charge transport through DNA. Our experiments on DNA bundles manipulated with silicon-based actuated tweezers demonstrate undoubtedly that humidity is the main factor affecting the electrical conduction in DNA. We explain the quasi-Ohmic behavior of DNA and the exponential dependence of its conductivity with relative humidity from the adsorption of water on the DNA backbone. We propose a quantitative model that is consistent with previous studies on DNA and other materials, like porous silicon, subjected to different humidity conditions. 相似文献
295.
296.
Shibata T Takahashi Y Tasaki J Saito Y Izutsu Y Maéno M 《Mechanisms of development》2008,125(3-4):284-298
We have characterized a cDNA clone, rdd (repeated D domain-like), that encodes for a secretory protein consisting of repeated domains of cysteine-rich sequence. Whole-mount in situ hybridization analysis revealed that rdd2, rdd3 and rdd4 are transiently expressed in the ventral and lateral mesoderm and the overlying ectoderm at the late gastrula and tailbud stages. Morpholino oligonucleotide (MO) was used to inhibit the translation of endogenous rdd3 and rdd4, and we found that the circulation of red blood cells completely disappears in the MO-injected tadpoles. Histological analysis showed that formation of the ventral aorta, dorsal aorta and posterior cardinal vein in the trunk region was severely disorganized in these animals. Injection of MO affected the expression of alpha-globin, a terminal differentiation marker of red blood cells, but did not affect the expression of scl, flk-1 or tie-2, suggesting that angiopoietic and hematopoietic precursor cells differentiate normally in the rdd-depleted embryo. The transplantation of labeled tissues followed by tracing of the donor cells revealed a role of rdds in migration of the embryonic angioblasts and myeloid cells. These observations first demonstrate the role of the novel cysteine-rich proteins in migration of the embryonic cells. 相似文献
297.
Noriko Ohyama Michiko Torio Kentaro Nakashima Yuuki Koga Shunsuke Kanno Hisanori Nishio Kei Nishiyama Momoko Sasazuki Haru Kato Hiroshi Asakura Satoshi Akamine Masafumi Sanefuji Yoshito Ishizaki Yasunari Sakai Shouichi Ohga 《Annals of clinical microbiology and antimicrobials》2017,16(1):61
Background
Botulism is a potentially fatal infection characterized by progressive muscle weakness, bulbar paralysis, constipation and other autonomic dysfunctions. A recent report suggested that cancer chemotherapy might increase the risk for the intestinal toxemia botulism in both adults and children.Case presentation
We report a 5-year-old boy, who developed general muscle weakness, constipation, ptosis and mydriasis during the third induction therapy for relapsed acute myeloid leukemia. He had recent histories of multiple antibiotic therapy for bacteremia and intake of well water at home. Repeated bacterial cultures identified Clostridium botulinum producing botulinum neurotoxin A. Botulinum toxin A was isolated from his stools at 17, 21, and 23 days after the onset. Symptoms were self-limiting, and were fully recovered without anti-botulinum toxin globulin therapy.Conclusion
This is the second report of a pediatric case with cancer chemotherapy-associated intestinal toxemia botulism. Our case provides further evidence that the immunocompromised status due to anti-cancer treatments increases the risk for the development of botulism at all ages in childhood.298.
The critical role of disulfide bond formation in protein sorting in the endosperm of rice 总被引:1,自引:0,他引:1
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Kawagoe Y Suzuki K Tasaki M Yasuda H Akagi K Katoh E Nishizawa NK Ogawa M Takaiwa F 《The Plant cell》2005,17(4):1141-1153
Many seed storage proteins, including monomeric 2S albumin and polymeric prolamin, contain conserved sequences in three separate regions, termed A, B, and C, which contain the consensus motifs LxxC, CCxQL, and PxxC, respectively. Protein-sorting mechanisms in rice (Oryza sativa) endosperm were studied with a green fluorescent protein (GFP) fused to different segments of rice α-globulin, a monomeric, ABC-containing storage protein. The whole ABC region together with GFP was efficiently transported to protein storage vacuoles (type II protein bodies [PB-II]) in the endosperm cells and sequestered in the matrix that surrounds the crystalloids. Peptide Gln-23 to Ser-43 in the A region was sufficient to guide GFP to PB-II. However, GFP fused with the AB or B region accumulated in prolamin protein bodies. Substitution mutations in the CCxQL motif in the B region significantly altered protein localization in the endosperm cells. Furthermore, protein extracts containing these substituted proteins had increased amounts of the endoplasmic reticulum (ER) chaperons BiP (for binding protein), protein disulfide isomerase, and calnexin as a part of protein complexes that were insoluble in a detergent buffer. These results suggest that the ER chaperons and disulfide bonds formed at the dicysteine residues in CCxQL play critical roles in sorting fused proteins in the endosperm cells. 相似文献
299.
Mutation Detection in DNA Oligonucleotides Based on a Guanine Quenching Method Coupled with Enzymatic Digestion of Single-Stranded DNA 总被引:1,自引:0,他引:1
Maruyama T Shinohara T Ichinose H Kitaoka M Okamura N Kamiya N Goto M 《Biotechnology letters》2005,27(18):1349-1354
Fluorescence quenching by guanine allows DNA hybridization to be monitored and any point mutations in oligonucleotides to
be detected. However, fluorescence quenching is often affected by untargeted guanine located in a protruding end (single-strand
DNA) of the probe-target DNA duplex resulting in an unsatisfactory sensitivity. In the present study, we used enzymatic digestion
of the protruding end of a probe-target DNA duplex to avoid interference by untargeted guanine on fluorescence quenching for
detection of a nucleobase mutation. Enzymatic digestion of the protruding end of the DNA duplex fully prevented interference
by untargeted guanine, and produced a marked difference in the quenching ratios (36% for wild-type, and 0% for mutant). 相似文献
300.
Asano K Suzuki K Chiba M Sera K Asano R Sakai T 《Biological trace element research》2005,107(2):135-140
The concentrations of 28 elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si,
Sr, Ti, V, Y, and Zn) were measured in mane hair by the particle-induced X-ray emission method. Except for Br, Cl, K, S, and
P, the trace element concentrations in mane hair of horses are similar to literature values for human hair. The values obtained
are not dependent on the horse's age, breed, and sex and could be used as reference values in the assessment of diseases and
nutritional status in equines. 相似文献