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排序方式: 共有196条查询结果,搜索用时 31 毫秒
111.
Jun Matsuzaki Mariko Norisada Jun Kodaira Makoto Suzuki Takeshi Tange 《Trees - Structure and Function》2005,19(2):198-203
The lower foliar photosynthetic rates seen in shoots in the upper crowns of tall trees than those in seedlings could be caused by extrinsic factors, such as hydraulic conductance, for shoots or by irreversible intrinsic change in the meristems during tree development. To clarify which is most significant, we compared foliar gas exchange characteristics and water relations among scions of Japanese cedar (Cryptomeria japonica D. Don) grafted into the upper crowns of tall trees, rooted cuttings developed from scions of the same clones, and intact shoots in the upper crowns of the tall trees. Grafted shoots had the same water regime as intact shoots, as confirmed by their similar water potentials at the turgor loss point, which were more negative than those of the rooted cuttings. No significant difference was observed between the grafted and intact shoots in their light-saturated photosynthetic rate (Pmax), stomatal conductance (gs), photosynthetic capacity, carboxylation efficiency, ratio of intercellular to ambient CO2 concentration (Ci/Ca), and carbon isotope composition (13C). Compared with the rooted cuttings, the grafted shoots showed significantly lower Pmax, gs, photosynthetic capacity, and carboxylation efficiency (to 49%, 31%, 68%, and 65%, respectively). The Ci/Ca and 13C indicated significantly stronger instantaneous and long-term stomatal limitation in the grafted shoots than in the rooted cuttings. These indicate that changes in extrinsic factors can reduce foliar photosynthetic rates in shoots in the upper crowns of tall trees as a result of stronger stomatal limitation and reduced photosynthetic activity, without irreversible intrinsic changes in the meristems. 相似文献
112.
Komatsu T Oguro Y Teramura Y Takeoka S Okai J Anraku M Otagiri M Tsuchida E 《Biochimica et biophysica acta》2004,1675(1-3):21-31
The recombinant human serum albumin (rHSA) dimer, which was cross-linked by a thiol group of Cys-34 with 1,6-bis(maleimido)hexane, has been physicochemically characterized. Reduction of the inert mixed-disulfide of Cys-34 beforehand improved the efficiency of the cross-linking reaction. The purified dimer showed a double mass and absorption coefficient, but unaltered molar ellipticity, isoelectric point (pI: 4.8) and denaturing temperature (65 degrees C). The concentration dependence of the colloid osmotic pressure (COP) demonstrated that the 8.5 g dL(-1) dimer solution has the same COP with the physiological 5 g dL(-1) rHSA. The antigenic epitopes of the albumin units are preserved after bridging the Cys-34, and the circulation lifetime of the 125I-labeled variant in rat was 18 h. A total of 16 molecules of the tetrakis[(1-methylcyclohexanamido)phenyl]porphinatoiron(II) derivative (FecycP) is incorporated into the hydrophobic cavities of the HSA dimer, giving an albumin-heme hybrid in dimeric form. It can reversibly bind and release O2 under physiological conditions (37 degrees C, pH 7.3) like hemoglobin or myoglobin. Magnetic circular dichroism (CD) revealed the formation of an O2-adduct complex and laser flash photolysis experiments showed the three-component kinetics of the O2-recombination reaction. The O2-binding affinity and the O2-association and -dissociation rate constants of this synthetic hemoprotein have also been evaluated. 相似文献
113.
Yuji Taniguchi Cornelia Appiah-Kwarteng Mami Murakami Junpei Fukumoto Kisaburo Nagamune Tomohide Matsuo Tatsunori Masatani Hirotaka Kanuka Tokio Hoshina Katsuya Kitoh Yasuhiro Takashima 《Parasitology international》2018,67(5):587-592
The virulence of a type III Toxoplasma gondii strain isolated in Japan and designated here as TgCatJpGi1/TaJ was examined in mice and micro minipigs in this study. Despite its type III genotype, oral or intraperitoneal inoculation of cysts from it resulted in severe virulence in C57BL/6J and BALB/c mice. In contrast, mice inoculated with a high dose of TgCatJpGi1/TaJ tachyzoites showed no obvious clinical signs of infection, and all of them survived for >21?days post-inoculation. Furthermore, no clinical signs of infection were seen when micro minipigs were inoculated with 900 cysts. Interestingly, our allelic type screening of the virulence-related rop5, rop16, rop17, and rop18 genes, as based on restriction fragment length polymorphism analysis (RFLP), revealed that the RFLP patterns for TgCatJpGi1/TaJ were identical to those from nonvirulent type III parasites. These results suggest that TgCatJpGi1/TaJ possesses an unknown virulence factor or factors. 相似文献
114.
Nobuo Kato Michio Ohta Yoshichika Arakawa Setsuko Naito Tsuyoshi Sugiyama Hideo Ito Nobuo Kido Kyoyu Sasaki Junpei Asai 《Microbiology and immunology》1996,40(6):407-413
An R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (O3–:K1–) formed crystals, whose shapes were elongated hexagonal plates, trapezoid plates, and rhomboid plates, and whose greatest dimensions were 3.1 × 0.8 μm, when it was suspended in 50 mM Tris buffer at pH 8.5 containing 5 mM MgCl2 and kept at 4 C for as long as 870 days. K. pneumoniae LEN-111 synthesized LPS molecules possessing incomplete repeating units of the O-antigenic polysaccharide portion besides the R-form LPS because of a leaky characteristic, but crystals consisted exclusively of the R-form LPS. Although the size of crystals was not large enough for X-ray analysis and limited crystallographic information was available, it was suggested that the crystals consist of hexagonal lattices with an a axis of 4.62 Å and c axis of 79.8 ±2.6 Å. The present results showed that R-form LPS lacking the O-antigenic polysaccharide portion tends to form crystals during long-term incubation in Tris buffer at pH 8.5 containing MgCl2 at 4 C. 相似文献
115.
Isolation of Hemagglutinin and Neuraminidase Subunits of Hemagglutinating Virus of Japan 总被引:3,自引:3,他引:0 下载免费PDF全文
Koichiro Maeno Tetsuya Yoshida Masao Iinuma Yoshiyuki Nagai Toshisada Matsumoto Junpei Asai 《Journal of virology》1970,6(4):492-499
When purified hemagglutinating virus of Japan (HVJ) was treated with trypsin, two major surface antigens were released from the virus. The "hemagglutinin" subunits obtained by this method were reactive with homologous hemagglutination-inhibition antibody and could be detected by an antibody-blocking test. They adsorbed to but did not agglutinate red cells and thus appeared to be "monovalent." The neuraminidase subunits were obtained in fully active form and did not adsorb to red cells. This finding suggests that these two activities of HVJ are associated with different subunits of the virus particle. The hemagglutinin and neuraminidase subunits could be partially separated by zonal rate centrifugation or gel filtration on Sephadex G-200. The molecular weights estimated for these subunits were approximately 124,000 and 114,000, respectively. After treatment with trypsin, virus-associated hemagglutinin and neuraminidase activities were both reduced significantly. The electron micrographs of such trypsinized virus particles showed complete or partial loss of surface projections. These results suggested that the subunits obtained by this method seemed to be those projections liberated from the virus by the action of trypsin. 相似文献
116.
Junpei Zhou Pengjun Shi Huoqing Huang Yanan Cao Kun Meng Peilong Yang Rui Zhang Xiaoyan Chen Bin Yao 《Applied microbiology and biotechnology》2010,88(6):1297-1309
The α-galactosidase gene, galA17, was cloned from Flavobacterium sp. TN17, a symbiotic bacterium isolated from the gut of Batocera horsfieldi larvae. The 2,205-bp full-length gene encodes a 734-residue polypeptide (GalA17) containing a putative 28-residue signal
peptide and a catalytic domain belonging to glycosyl hydrolase family 36 (GH 36). The deduced amino acid sequence of galA17 was most similar to a putative α-galactosidase from Pedobacter sp. BAL39 (EDM38577; 66.6% identity) and a characterized α-galactosidase from Carnobacterium piscicola BA (AAL27305; 30.1%). Phylogenetic analysis revealed that GalA17 was similar to GH 36 α-galactosidases from symbiotic bacteria
sharing two putative catalytic motifs, KWD and SDXXDXXXR, in which D480, S548, D549, and R556 were essential for α-galactosidase
activity based on site-directed mutagenesis. Purified recombinant GalA17 showed apparent optimal activity at pH 5.5 and 45°C;
exhibited strong resistance to digestion by trypsin, α-chymotrypsin, collagenase, and proteinase K; and efficiently hydrolyzed
several synthetic and natural substrates (p-nitrophenyl-α-d-galactopyranoside, stachyose, melibiose, raffinose, soybean meal, locust bean gum, and guar gum). 相似文献
117.
Soil fertilization is a common practice in modern agriculture, undertaken to prevent nutrient deficiency in crops. However, fertilization is costly and causes environmental pollution. The cultivation of plants that tolerate low nutrient supplies may circumvent this problem. Here, we report the generation of Arabidopsis thaliana plants that tolerate boron (B)-deficient conditions due to the overexpression of BOR1, an efflux B transporter that is required for efficient xylem loading of B. In several independently generated transgenic plants expressing BOR1 or BOR1-GFP under the control of the cauliflower mosaic virus 35S RNA promoter, root-to-shoot translocation of B was enhanced and shoot growth was greater under B-limiting conditions compared with wild-type plants. In addition, the transgenic plants showed increased translocation of B, especially to the shoot apex, and set seed normally under B-limiting conditions, under which wild-type plants failed to set seed. This study therefore reports plants that show improved seed yields compared with wild-type under nutrient-deficient conditions as a result of increased production of an essential mineral nutrient transporter. 相似文献
118.
119.
Nakae Y Hirasaka K Goto J Nikawa T Shono M Yoshida M Stoward PJ 《Histochemistry and cell biology》2008,129(4):489-501
Dystrophic muscles suffer from enhanced oxidative stress. We have investigated whether administration of an antioxidant, epigallocatechin-3-gallate
(EGCG), a component of green tea, reduces their oxidative stress and pathophysiology in mdx mice, a mild phenotype model of human Duchenne-type muscular dystrophy. EGCG (5 mg/kg body weight in saline) was injected
subcutaneously 4× a week into the backs of C57 normal and dystrophin-deficient mdx mice for 8 weeks after birth. Saline was injected into normal and mdx controls. EGCG had almost no observable effects on normal mice or on the body weights of mdx mice. In contrast, it produced the following improvements in the blood chemistry, muscle histology, and electrophysiology
of the treated mdx mice. First, the activities of serum creatine kinase were reduced to normal levels. Second, the numbers of fluorescent lipofuscin
granules per unit volume of soleus and diaphragm muscles were significantly decreased by about 50% compared to the numbers
in the corresponding saline-treated controls. Third, in sections of diaphragm and soleus muscles, the relative area occupied
by histologically normal muscle fibres increased significantly 1.5- to 2-fold whereas the relative areas of connective tissue
and necrotic muscle fibres were substantially reduced. Fourth, the times for the maximum tetanic force of soleus muscles to
fall by a half increased to almost normal values. Fifth, the amount of utrophin in diaphragm muscles increased significantly
by 17%, partially compensating for the lack of dystrophin expression. 相似文献
120.
Takuro Sado Fumio Miyamoto Kuniichiro Yano Ichiro Sako Hideo Ose Junpei Watanabe 《Bioscience, biotechnology, and biochemistry》2013,77(2):77-82
Nineteen new alkylmercurithio derivatives were synthesized, and their antibacterial and antifungal activities were studied in comparison with Thimerosal, a representative commercial mercurial disinfectant. All the substances tested showed stronger activities than the latter agent. Among them, methylmercurithioacetamide was recognized as the most suitable remedy for dermatomycosis because of its high solubility and stability in alcoholic solvents for tincture preparation, its good effect in the treatment of experimental trichophytosis of guinea-pigs, its low, acute and chronic toxicities and its lack of clinical side effects. 相似文献