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991.
To evaluate the effects of air pollution on the decline of Pinus densiflora forests, various research has been conducted around Mt. Gokurakuji (34° 23N, 132° 19E, 693 m a.s.l.) north of the Seto Inland Sea, west Japan. To investigate the mechanisms responsible for decreases in photosynthesis (Pn) and stomatal conductance (gl), 13C of needles and seasonal changes in the water content (WC) and abscisic acid concentration (ABA) of needles were measured in various stands. The 13C values were less negative in declining stands and younger needles. ABA and WC were not correlated with each other. WC decreased consistently with needle age while the ABA showed a minimum in August and a smaller content in older needles. Monthly precipitation and the daily maximum vapor pressure were not correlated with ABA and WC. In declining stands, WC and ABA tended to be higher and lower, respectively, than in nondeclining stands. These results suggest that the trees in declining stands received less water stress than those in nondeclining stands and the differences in gl and 13C are not caused by the difference in water stress. The possibilities of the effects of air pollution and the infection of pine-wood nematode on the physiological decline on the pine needles are discussed. 相似文献
992.
AimsThe potential of human mesenchymal stem cell-like stroma prepared from placental/umbilical cord blood for hematopoietic regeneration by X-irradiated hematopoietic stem cells is herein assessed.Main methodsPlacental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells were applied to a regenerative ex vivo expansion of X-irradiated human CD34+ cells in a serum-free liquid culture supplemented with a combination of interleukine-3 plus stem cell factor plus thrombopoietin.Key findingsThe total number of cells and of lineage-committed myeloid hematopoietic progenitor cells generated in the co-culture of both non-irradiated and X-irradiated cells with stromal cells was significantly higher than those in the stroma-free culture. In addition, the number of CD34+ cells and CD34+/CD38? cells, immature hematopoietic stem/progenitor cells also increased more than the stroma-free culture. The stromal cells produced various types of cytokines, although there was little difference between the co-cultures of non-irradiated and X-irradiated cells with stromal cells. Furthermore, when X-irradiated cells came in contact with stromal cells for 16 h before cytokine stimulation, a similar degree of hematopoiesis was observed, thus suggesting the critical role of cell-to-cell interaction.SignificanceThe present results showed the potential efficacy of human mesenchymal stem cell-like stroma for hematopoietic regeneration from irradiated hematopoietic stem/progenitor cells. 相似文献
993.
Identification of maize silicon influx transporters 总被引:1,自引:1,他引:0
Maize (Zea mays L.) shows a high accumulation of silicon (Si),but transporters involved in the uptake and distribution havenot been identified. In the present study, we isolated two genes(ZmLsi1 and ZmLsi6), which are homologous to rice influx Sitransporter OsLsi1. Heterologous expression in Xenopus laevisoocytes showed that both ZmLsi1 and ZmLsi6 are permeable tosilicic acid. ZmLsi1 was mainly expressed in the roots. By contrast,ZmLsi6 was expressed more in the leaf sheaths and blades. Differentfrom OsLsi1, the expression level of both ZmLsi1 and ZmLsi6was unaffected by Si supply. Immunostaining showed that ZmLsi1was localized on the plasma membrane of the distal side of rootepidermal and hypodermal cells in the seminal and crown roots,and also in cortex cells in lateral roots. In the shoots, ZmLsi6was found in the xylem parenchyma cells that are adjacent tothe vessels in both leaf sheaths and leaf blades. ZmLsi6 inthe leaf sheaths and blades also exhibited polar localizationon the side facing towards the vessel. Taken together, it canbe concluded that ZmLsi1 is an influx transporter of Si, whichis responsible for the transport of Si from the external solutionto the root cells and that ZmLsi6 mainly functions as a Si transporterfor xylem unloading. 相似文献
994.
995.
Toshifumi Sakaguchi Masaki Kato Naoki Kuriyama Harutaka Niiyama Shougo Hamada Yasutaka Morita Eiichi Tamiya 《Current microbiology》2009,59(1):88-94
Conjugal mating between selenate-reducing Citrobacter sp. strain JSA and Escherichia coli S17-1 bearing pSUP2021 allowed transposon mutagenesis and chromosomal transformation. Kanamycin-resistant transconjugants
were obtained successfully by this method from a freshwater selenate-respiring Citrobacter sp. strain JSA. The maximum frequency of kanamycin-resistant Tn5 transconjugants was 3.6 × 10−6 per recipient of this strain. Of these transconjugants, eight strains of selenate reduction-deficient transconjugants living
by nitrate reduction were obtained in the strain JSA. Moreover, the same phenotype of deficient mutant was created by chemical
mutagenesis with ethylmethanesulfonate. The results strongly indicate that selenate reducing anaerobic respiration was independent
of nitrate reduction in the Citrobacter sp. isolate strain JSA. 相似文献
996.
Kaori Tanaka Tsukasa Hori Naoki Hatakeyama Masaki Yamamoto Rumiko Takayama Yuko Yoto Nobuhiro Suzuki Toshiaki Hayashi Yukiho Ikeda Hiroshi Ikeda Tadao Ishida Hiroyuki Tsutsumi 《Microbiology and immunology》2009,53(6):319-322
BK polyomavirus (BKV) is ubiquitous among humans, usually infecting them asymptomatically during childhood. BKV persists in renal tissue of individuals and their progeny are excreted in urine, particularly in immunocompromised patients. JC virus, another human polyomavirus, has been considered to be transmitted from parents to children during prolonged cohabitation. However, BKV has been supposed to be transmitted not only within but also outside the family. In the present study, to clarify this possibility, we analyzed phylogenetically 35 BKV which were excreted in the urine by Japanese children and adults undergoing stem cell transplantation. Subtypes I, III and IV were detected in 15, two and one children and in 15, one and one adults, respectively. Among 15 subtype I isolates from children, three, four and eight belonged to subgroups Ia, Ib-1 and Ic, respectively. All the three children from whom Ia was detected were less than 9 years old. In contrast in the adults, three subtype I belonged to Ib-1 and the other 12 to Ic. These findings may reflect the recent transmission of BKV Ia strains to Japanese children. 相似文献
997.
Kazumi Shimono Mie Goto Takashi Kikukawa Seiji Miyauchi Mikako Shirouzu Naoki Kamo Shigeyuki Yokoyama 《Protein science : a publication of the Protein Society》2009,18(10):2160-2171
Cell‐free expression has become a highly promising tool for the efficient production of membrane proteins. In this study, we used a dialysis‐based Escherichia coli cell‐free system for the production of a membrane protein actively integrated into liposomes. The membrane protein was the light‐driven proton pump bacteriorhodopsin, consisting of seven transmembrane α‐helices. The cell‐free expression system in the dialysis mode was supplemented with a combination of a detergent and a natural lipid, phosphatidylcholine from egg yolk, in only the reaction mixture. By examining a variety of detergents, we found that the combination of a steroid detergent (digitonin, cholate, or CHAPS) and egg phosphatidylcholine yielded a large amount (0.3–0.7 mg/mL reaction mixture) of the fully functional bacteriorhodopsin. We also analyzed the process of functional expression in our system. The synthesized polypeptide was well protected from aggregation by the detergent‐lipid mixed micelles and/or lipid disks, and was integrated into liposomes upon detergent removal by dialysis. This approach might be useful for the high yield production of functional membrane proteins. 相似文献
998.
Shohei Hamada Tae-Dong Kim Takayoshi Suzuki Yukihiro Itoh Hiroki Tsumoto Hidehiko Nakagawa Ralf Janknecht Naoki Miyata 《Bioorganic & medicinal chemistry letters》2009,19(10):2852-2855
N-Oxalylglycine (NOG) derivatives were synthesized, and their inhibitory effect on histone lysine demethylase activity was evaluated. NOG and compound 1 inhibited histone lysine demethylases JMJD2A, 2C and 2D in enzyme assays, and their dimethyl ester prodrugs DMOG and 21 exerted histone lysine methylating activity in cellular assays. 相似文献
999.
1000.
Natsuko Miura Wataru Aoki Naoki Tokumoto Kouichi Kuroda Mitsuyoshi Ueda 《Applied microbiology and biotechnology》2009,85(2):293-301
We developed a novel method to coat living non-genetically modified (GM) cells with functional recombinant proteins. First,
we prepared GM yeast to secrete constructed proteins that have two domains: a functional domain and a binding domain that
recognizes other cells. Second, we cocultivated GM and non-GM yeasts that share and coutilize the medium containing recombinant
proteins produced by GM yeasts using a filter-membrane-separated cultivation reactor. We confirmed that GM yeast secreted
enhanced green fluorescent protein (EGFP) fusion proteins to culture medium. After cocultivation, EGFP fusion proteins produced
by GM yeast were targeted to non-GM yeast (Saccharomyces cerevisiae BY4741ΔCYC8 strain) cell surface. Yeast cell-surface engineering is a useful method that enables the coating of GM yeast cell surface
with recombinant proteins to produce highly stable and accumulated protein particles. The results of this study suggest that
development of cell-surface engineering from GM organisms (GMOs) to living non-GMOs by our novel cocultivation method is possible. 相似文献