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941.
Hisashi Kato-Noguchi Yoshiko Fushimi Yukitoshi Tanaka Toshiaki Teruya Kiyotake Suenaga 《Plant Growth Regulation》2011,65(2):299-304
Since red pine (Pinus densiflora Sieb. et Zucc.) often forms sparse forest floors where herbaceous plants do not grow well, allelopathy of red pine was investigated.
A growth inhibitory substance was isolated from an aqueous methanol extract of red pine needles and determined by spectral
data as abscisic acid-β-d-glucopyranosyl ester (ABA-GE). This substance inhibited root and shoot growth of cress and E. crus-galli seedlings at concentrations greater than 0.1 μM. The concentrations required for 50% growth inhibition on roots and shoots
of cress were 0.23 and 0.61 μM, respectively, and those of E. crus-galli were 1.1 and 2.8 μM, respectively. The activity of ABA-β-d-glucosidase, which liberates free ABA from ABA-GE, in cress and E. crus-galli seedlings was 13–29 nmol mg−1 protein min−1. Endogenous concentration of ABA-GE in the pine needles was 4.1–21.5 μmol kg−1 and the concentration in soil water of the pine forest was 2.5 μM. The effectiveness of ABA-GE on growth inhibition and the
occurrence of ABA-GE in pine needles and soil water suggest ABA-GE may play an important role in the allelopathy of red pine
resulting in the formation of sparse forest floors. 相似文献
942.
Aspergillus awamori K4 β-xylosidase has broad acceptor specificity. It has been used to synthesize a sugar fatty acid ester via its transxylosylation
activity. One xylosyl residue was initially transferred to hexamethylene glycol as a linker with a yield of 0.36 g/g xylobiose.
Linoleic acid was subsequently linked to one terminal hydroxyl side of the transfer product hydroxyhexyl xyloside through
an esterification reaction catalyzed by a lipase. The synthesis of hexyl linoleoyl xyloside was confirmed by TOF-MS analysis.
The binding with a linker improved the esterification reaction because of the hydrophobic hexamethylene chain and also prevented
steric hindrance by the xylosyl residue. This sugar fatty acid ester synthesis method using transglycosylation should facilitate
the production of emulsifiers or surfactants with various functions. 相似文献
943.
Takeichi T Takarada-Iemata M Hashida K Sudo H Okuda T Kokame K Hatano T Takanashi M Funabe S Hattori N Kitamura O Kitao Y Hori O 《Neurochemistry international》2011,59(1):21-27
N-myc downstream-regulated gene 2 (Ndrg2) is a differentiation- and stress-associated molecule predominantly expressed in astrocytes in the central nervous system (CNS). To study the expression and possible role of Ndrg2 in quiescent and activated astrocytes, mice were administrated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP), a Parkinson disease (PD)-related neurotoxin which causes both neurodegeneration and glial activation. Immunohistological analysis revealed that Ndrg2 was highly expressed in both types of astrocytes, but less so in astrocytes during the early process of activation. Ndrg2 was also expressed in astrocyte-like cells, but not in neurons, in human brains from PD and Cortico-basal degeneration (CBD) patients. In cultured astrocytes, gene silencing of Ndrg2 significantly enhanced the numbers of 5-bromo-2′-deoxy-uridine (BrdU)-incorporated and proliferating cell nuclear antigen (PCNA)-positive cells, and reduced the length of cell processes and the amount of F-actin. In contrast, adenovirus-mediated overexpression of Ndrg2 significantly reduced the numbers of BrdU-incorporated and PCNA-positive cells, and enhanced the amount of F-actin. Fractionation and immunocytochemical analysis further revealed that Ndrg2 was located in different cellular fractions including the cytosol and cell surface membranes. These results suggest that Ndrg2 may regulate astroglial activation through the suppression of cell proliferation and stabilization of cell morphology. 相似文献
944.
945.
Lancefield group C Streptococcus dysgalactiae (GCSD) is known as a causative agent of bovine mastitis and cardiopulmonary diseases in humans. Recently, GCSD has been isolated from diseased fish in Japan. Almost all culture supernatants and sodium dodecyl sulfate extracts obtained from GCSD isolated from farmed fish possessed serum opacity activity. Serum opacity factor (SOF) is a bifunctional cell-associated protein that causes serum opacification. In this study, a gene coding SOF, which was named sof-FD, was identified from GCSD isolated from fish. The amino acid sequence of sof-FD showed 40.1-46.5% identity to those of other SOFs from mammalian strains of S. dysgalactiae and Streptococcus pyogenes. Repetitive fibronectin binding domains were also observed in sof-FD, the structures of which were similar to those of other SOFs, as previously reported. The amino acid sequence of SOF was identical among fish isolates. A primer set targeting the sof-FD gene was designed and applied to a PCR assay for discriminating fish isolates from mammalian isolates. 相似文献
946.
Ohno H Nakatsu Y Sakoda H Kushiyama A Ono H Fujishiro M Otani Y Okubo H Yoneda M Fukushima T Tsuchiya Y Kamata H Nishimura F Kurihara H Katagiri H Oka Y Asano T 《American journal of physiology. Cell physiology》2011,300(5):C1047-C1054
Glucose transporter 1 (GLUT1) is widely distributed throughout various tissues and contributes to insulin-independent basal glucose uptake. Using a split-ubiquitin membrane yeast two-hybrid system, we newly identified 4F2 heavy chain (4F2hc) as a membrane protein interacting with GLUT1. Though 4F2hc reportedly forms heterodimeric complexes between amino acid transporters, such as LAT1 and LAT2, and regulates amino acid uptake, we investigated the effects of 4F2hc on GLUT1 expression and the associated glucose uptake. First, FLAG-tagged 4F2hc and hemagglutinin-tagged GLUT1 were overexpressed in human embryonic kidney 293 cells and their association was confirmed by coimmunoprecipitation. The green fluorescent protein-tagged 4F2hc and DsRed-tagged GLUT1 showed significant, but incomplete, colocalization at the plasma membrane. In addition, an endogenous association between GLUT1 and 4F2hc was demonstrated using mouse brain tissue and HeLa cells. Interestingly, overexpression of 4F2hc increased the amount of GLUT1 protein in HeLa and HepG2 cells with increased glucose uptake. In contrast, small interfering RNA (siRNA)-mediated 4F2hc gene suppression markedly reduced GLUT1 protein in both cell types, with reduced glucose uptake. While GLUT1 mRNA levels were not affected by overexpression or gene silencing of 4F2hc, GLUT1 degradation after the addition of cycloheximide was significantly suppressed by 4F2hc overexpression and increased by 4F2hc siRNA treatment. Taken together, these observations indicate that 4F2hc is likely to be involved in GLUT1 stabilization and to contribute to the regulation of not only amino acid but also glucose metabolism. 相似文献
947.
948.
Yanaka M Honma T Sato K Shinohara N Ito J Tanaka Y Tsuduki T Ikeda I 《Bioscience, biotechnology, and biochemistry》2011,75(6):1098-1103
We investigated whether replicative senescence of endothelial cells contributed to the pathogenesis of atherosclerosis in human umbilical vein endothelial cells (HUVECs). HUVECs at a population-doubling level of 30 (PDL30) divided much more slowly than those at PDL9. The percentage of SA-β-Gal-positive cells and the mRNA expression levels of PAI-1 and p21 at PDL30 were significantly higher than those at PDL9. The changes induced by aging were evaluated according to the mRNA expression level of genes related to the endothelial cell function. The expression level of many adhesion molecules promoting monocytic adhesion was significantly increased, and monocytic adhesion on HUVECs was found to be significantly promoted by aging. Monocytic adhesion is an essential early event in the development of atherosclerosis, and our results suggest that replicative senescence of the vascular endothelial cells induced increased expression of adhesion molecules. The consequent increase in monocytic adhesion may then promote the pathogenesis of atherosclerosis. 相似文献
949.
Tashiro Y Inagaki A Shimizu M Ichikawa S Takaya N Nakajima-Kambe T Uchiyama H Nomura N 《Bioscience, biotechnology, and biochemistry》2011,75(3):605-607
Many Gram-negative bacteria release membrane vesicles (MVs), but their phospholipid properties are poorly understood. Phosphatidylglycerol was present at high levels in MVs derived from Pseudomonas aeruginosa, but not in the cellular outer membrane. The ratio of stearic acid in MVs was high compared to that in the cellular outer membrane. These findings suggest that membrane rigidity is associated with MV biogenesis. 相似文献
950.
Functional analysis of the cyclopiazonic acid biosynthesis gene cluster in Aspergillus oryzae RIB 40
The cyclopiazonic acid (CPA) nonproducing strain, Aspergillus oryzae RIB 40, does not biosynthesize cyclo-acetoacetyl-L-tryptophan (cAATrp) due to a truncation in the responsible PKS-NRPS gene. We found that RIB 40 converted cAATrp to 2-oxocyclopiazonic acid, the final product of CPA biosynthesis in A. oryzae. This indicates that the CPA biosynthesis gene cluster, except for the PKS-NRPS gene, is functional in RIB 40. 相似文献