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991.
Kotoku N Kato T Narumi F Ohtani E Kamada S Aoki S Okada N Nakagawa S Kobayashi M 《Bioorganic & medicinal chemistry》2006,14(22):7446-7457
In order to increase metabolic stability and water solubility of arenastatin A, an extremely potent cytotoxic depsipeptide from the Okinawan marine sponge of Dysidea arenaria, several 15,20-triamide analogues with a polar substituent on the phenyl ring were synthesized. The 15,20-triamide analogues with a polar substituent (24, 30, and 31) showed increased solubility to MeOH and stronger cytotoxicity against KB cells in comparison with the parental 15,20-triamide analogue (2). Furthermore, the diethylamine analogue (30) exhibited in vivo anti-tumor activity against subcutaneously implanted murine sarcoma. 相似文献
992.
Denitrificationis a biological processin which nitrateand/or nitrite is reduced to gaseous nitrogen,dinitrogen(N2)or nitrous oxide(N2O)while carbon dioxide is thesecond gaseous product of the process.This is one of themain mechanisms of the global nitrogen cycle,and playsanimportant role as the reverse reaction of nitrogen fixa-tion in maintaining global environmental homeostasis[1].Denitrification has beenlongthought to be a unique char-acteristic of prokaryotes[2,3].Anumber of bacteria(such… 相似文献
993.
Guianfranco Mazzei Ryohei Ikegami Nona Abolhassani Naoki Haruyama Kunihiko Sakumi Takashi Saito Takaomi C. Saido Yusaku Nakabeppu 《Aging cell》2021,20(8)
Insulin resistance and diabetes mellitus are major risk factors for Alzheimer''s disease (AD), and studies with transgenic mouse models of AD have provided supportive evidence with some controversies. To overcome potential artifacts derived from transgenes, we used a knock‐in mouse model, AppNL−F/NL−F , which accumulates Aβ plaques from 6 months of age and shows mild cognitive impairment at 18 months of age, without the overproduction of APP. In the present study, 6‐month‐old male AppNL−F/NL−F and wild‐type mice were fed a regular or high‐fat diet (HFD) for 12 months. HFD treatment caused obesity and impaired glucose tolerance (i.e., T2DM conditions) in both wild‐type and AppNL−F/NL−F mice, but only the latter animals exhibited an impaired cognitive function accompanied by marked increases in both Aβ deposition and microgliosis as well as insulin resistance in the hippocampus. Furthermore, HFD‐fed AppNL−F/NL−F mice exhibited a significant decrease in volume of the granule cell layer in the dentate gyrus and an increased accumulation of 8‐oxoguanine, an oxidized guanine base, in the nuclei of granule cells. Gene expression profiling by microarrays revealed that the populations of the cell types in hippocampus were not significantly different between the two mouse lines, regardless of the diet. In addition, HFD treatment decreased the expression of the Aβ binding protein transthyretin (TTR) in AppNL−F/NL−F mice, suggesting that the depletion of TTR underlies the increased Aβ deposition in the hippocampus of HFD‐fed AppNL−F/NL−F mice. 相似文献
994.
Inoue T Nagatomi Y Kinami T Uyama A Mochizuki N 《Bioscience, biotechnology, and biochemistry》2010,74(12):2518-2522
Moromi (the fermented mash) of "mugi shochu" that had been artificially contaminated with pesticides was distilled to elucidate the fate of pesticides in the distillation process. The pesticides residing in the distillate were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Of the analyzed pesticides (249 compounds), 89% were not detected in the distillate, showing that the distillation process minimized the risk of pesticide contamination. 相似文献
995.
Asako Matsumoto Kohji Uchida Yuriko Taguchi Naoki Tani Yoshihiko Tsumura 《Journal of plant research》2010,123(5):689-699
The genetic diversity and population structure of hinoki (Chamaecyparis obtusa) in Japan were investigated by examining the distribution of alleles at 13 microsatellite loci in 25 natural populations
from Iwaki in northern Japan to Yakushima Island in southern Japan. On average, 26.9 alleles per locus were identified across
all populations and 4.0% of the genetic variation was retained among populations (G
ST = 0.040). According to linkage disequilibrium analysis, estimates of effective population size and detected evidence of bottleneck
events, the genetic diversity of some populations may have declined as a result of fragmentation and/or over-exploitation.
The central populations located in the Chubu district appear to have relatively large effective population sizes, while marginal
populations, such as the Yakushima, Kobayashi and Iwaki populations, have smaller effective population sizes and are isolated
from the other populations. Microsatellite analysis revealed the genetic uniqueness of the Yakushima population. Although
genetic differentiation between populations was low, we detected a gradual cline in the genetic structure and found that locus
Cos2619 may be non-neutral with respect to natural selection. 相似文献
996.
Yasunori Fukumoto Yuuki Obata Kenichi Ishibashi Naoki Tamura Ikue Kikuchi Kazumasa Aoyama Yasuyuki Hattori Kunihiko Tsuda Yuji Nakayama Naoto Yamaguchi 《Cytotechnology》2010,62(1):73-82
Introduction of genetic material into cells is an essential prerequisite for current research in molecular cell biology. Although
transfection with commercially available reagents results in excellent gene expression, their high costs are obstacles to
experimentation with a large number or large scales of transfection. The cationic polymer linear-polyethylenimine (MW 25,000)
(PEI), one of the most cost-effective vehicles, facilitates DNA compaction by polyplex formation, which leads to efficient
delivery of DNA into cells by endocytosis. However, the use of PEI is still limited because of substantial cytotoxicity and
intolerable deterioration in transfection efficiency by its low stability. Here, we show that acidification of PEI is important
for its transfection activity. Dissolving PEI powder in 0.2N HCl confers a long shelf-life for PEI storage at 4 and −80 °C,
and the polyplex formation of plasmid DNA with PEI is optimized in lactate-buffered saline at pH 4.0. Furthermore, changing
the culture medium at 8–12 h posttransfection can minimize the cytotoxicity of PEI without sacrificing the high transfection
efficiency comparable to that of commercial reagents. The cost per test using acidified PEI is drastically reduced to approximately
1:10,000, compared with commercial reagents. Thus, we conclude that acidification of PEI satisfactorily accomplishes cost-effective,
high-efficiency transfection. 相似文献
997.
Biodegradation of diphenylarsinic acid to arsenic acid by novel soil bacteria isolated from contaminated soil 总被引:2,自引:0,他引:2
Naoki Harada Kazuhiro Takagi Koji Baba Kunihiko Fujii Akio Iwasaki 《Biodegradation》2010,21(3):491-499
Microorganisms capable of degrading diphenylarsinic acid (DPAA) were enriched from contaminated soil using the soil-charcoal
perfusion method. Two novel bacterial strains, L2406 and L2413, that can degrade DPAA in a mineral salt medium supplemented
with DPAA as the sole carbon source were isolated. Based on comparative morphology, physiology, and comparison of the 16S
rRNA gene sequences, both were presumed to be species closely related to Ensifer adhaerens. As the metabolites, phenylarsonic acid (PAA) was determined by liquid chromatography-mass spectrometry analysis as well
as three unknown peaks all of whose molecular weights were estimated to be 278. The increase of m/z = 16 from DPAA in the
unknowns suggests monohydroxylation of DPAA at the 2-, 3- and 4-positions. The ability of strains L2406 and L2413 to degrade
DPAA was suppressed in iron insufficient conditions, e.g. less than 7.2 μM iron in the culture medium. These facts strongly
suggest the following hypothesis: Monooxygenase works at the initial degradation step of DPAA degradation by the isolates;
and direct hydrolysis from DPAA to PAA is not likely to occur. In addition, release of arsenic acid from PAA by strain L2406
was confirmed by liquid chromatography-inductively coupled plasma mass spectrometry. From these results, strain L2406 was
considered to be capable of degrading DPAA to arsenic acid via PAA when DPAA was supplied as the sole carbon source. 相似文献
998.
Zhuo Xu Naoki Ichikawa Keisuke Kosaki Yoshihiko Yamada Takako Sasaki Lynn Y. Sakai Hisashi Kurosawa Nobutaka Hattori Eri Arikawa-Hirasawa 《Matrix biology》2010,29(6):461-470
Perlecan is a component of the basement membrane that surrounds skeletal muscle. The aim of the present study is to identify the role of perlecan in skeletal muscle hypertrophy and myostatin signaling, with and without mechanical stress, using a mouse model (Hspg2?/?-Tg) deficient in skeletal muscle perlecan. We found that myosin heavy chain (MHC) type IIb fibers in the tibialis anterior (TA) muscle of Hspg2?/?-Tg mice had a significantly increased fiber cross-sectional area (CSA) compared to control (WT-Tg) mice. Hspg2?/?-Tg mice also had an increased number of type IIx fibers in the TA muscle. Myostatin and its type I receptor (ALK4) expression was substantially decreased in the Hspg2?/?-Tg TA muscle. Myostatin-induced Smad activation was also reduced in a culture of myotubes from the Hspg2?/?-Tg muscle, suggesting that myostatin expression and its signaling were decreased in the Hspg2?/?-Tg muscle. To examine the effects of mechanical overload or unload on fast and slow muscles in Hspg2?/?-Tg mice, we performed tenotomy of the plantaris (fast) muscle and the soleus (slow) muscle. Mechanical overload on the plantaris muscle of Hspg2?/?-Tg mice significantly increased wet weights compared to those of control mice, and unloaded plantaris muscles of Hspg2?/?-Tg mice caused less decrease in wet weights compared to those of control mice. The decrease in myostatin expression was significantly profound in the overloaded plantaris muscle of Hspg2?/?-Tg mice, compared with that of control mice. In contrast, overloading the soleus muscle caused no changes in either type of muscle. These results suggest that perlecan is critical for maintaining fast muscle mass and fiber composition, and for regulating myostatin signaling. 相似文献
999.
Akio Uemura Tetsuo Takehara Takuya Miyagi Takahiro Suzuki Tomohide Tatsumi Kazuyoshi Ohkawa Tatsuya Kanto Naoki Hiramatsu Norio Hayashi 《Cancer immunology, immunotherapy : CII》2010,59(3):453-463
Although the anti-tumor effect of IL-12 is mediated mostly by IFNγ, which cell types most efficiently produce IFNγ and therefore
initiate or promote the anti-tumor effect of IL-12 has not been clearly determined. In the present study, we demonstrated
hydrodynamic injection of the IL-12 gene led to prolonged IFNγ production, NK-cell activation and complete inhibition of liver
metastasis of CT-26 colon cancer cells in wild-type mice, but not in IFNγ knockout mice. NK cells expressed higher levels
of STAT4 and upon IL-12 administration displayed stronger STAT4 phosphorylation and IFNγ production than non-NK cells. Adoptive
transfer of wild-type NK cells into IFNγ knockout mice restored IL-12-induced IFNγ production, NK-cell activation and anti-tumor
effect, whereas transfer of the same number of wild-type non-NK cells did not. In conclusion, NK cells are predominant producers
of IFNγ that is critical for IL-12 anti-tumor therapy. 相似文献