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41.
Artificial extracellular matrix (ECM) proteins have been designed that have strong cell-adhesive activity and active functional units that inhibit network formation among vascular endothelial cells. A laminin-derived sequence (YIGSR) that blocks migration of vascular endothelial cells was designed to incorporate into an elastin-derived structural unit. The designed ECM fusion protein also had a cell-adhesive RGDN sequence that conferred an intense migration-inhibitory effect. The resultant ECM showed cell-adhesive activity superior to that of the synthetic YIGSR peptide and it blocked the migration of vascular endothelial cells. Furthermore, the designed ECM inhibited the angiogenic activity of a collagen gel. The engineering strategy of designing multi-functional ECM proteins could be applied to support novel tissue engineering techniques. 相似文献
42.
Larsen A Kolind K Pedersen DS Doering P Pedersen MO Danscher G Penkowa M Stoltenberg M 《Histochemistry and cell biology》2008,130(4):681-692
Traumatic brain injury results in loss of neurons caused as much by the resulting neuroinflammation as by the injury. Gold salts are known to be immunosuppressive, but their use are limited by nephrotoxicity. However, as we have proven that implants of pure metallic gold release gold ions which do not spread in the body, but are taken up by cells near the implant, we hypothesize that metallic gold could reduce local neuroinflammation in a safe way. Bio-liberation, or dissolucytosis, of gold ions from metallic gold surfaces requires the presence of disolycytes i.e. macrophages and the process is limited by their number and activity. We injected 20-45 mum gold particles into the neocortex of mice before generating a cryo-injury. Comparing gold-treated and untreated cryolesions, the release of gold reduced microgliosis and neuronal apoptosis accompanied by a transient astrogliosis and an increased neural stem cell response. We conclude that bio-liberated gold ions possess pronounced anti-inflammatory and neuron-protective capacities in the brain and suggest that metallic gold has clinical potentials. Intra-cerebral application of metallic gold as a pharmaceutical source of gold ions represents a completely new medical concept that bypasses the blood-brain-barrier and allows direct drug delivery to inflamed brain tissue. 相似文献
43.
Induction of endothelial apoptosis by 4-hydroxyhexenal. 总被引:1,自引:0,他引:1
Ji Young Lee Jeong Hwan Je Dae Hyun Kim Sang Woon Chung Yani Zou Nam Deuk Kim Mie Ae Yoo Hyung Suck Baik Byung Pal Yu Hae Young Chung 《European journal of biochemistry》2004,271(7):1339-1347
Lipid peroxidation and its products such as 4-hydroxy-2-nonenal (HNE) and 4-hydroxyhexenal (HHE) are known to affect redox balance during aging and various degenerative processes, including vascular dysfunction. Deterioration of the endothelial cells that line the vascular wall is known to be an underlying cause of vascular dysfunction. At present, little is known about the mechanism by which HHE induces endothelial cell death (i.e. apoptosis), although HNE-induced apoptotic cell death has been reported. The aim of this study was to determine whether apoptosis induced by HHE in endothelial cells involves peroxynitrite (ONOO(-)). Our results show that in endothelial cells HHE triggers apoptotic cell death by inducing apoptotic Bax coupled with a decrease in anti-apoptotic Bcl-2. Results show that HHE induces reactive oxygen species (ROS), nitric oxide, and ONOO(-) generation, leading to redox imbalance. Furthermore, the antioxidant N-acetyl cysteine, ROS scavenger, and penicillamine, an ONOO(-) scavenger, were found to block HHE-mediated apoptosis. We used confocal laser microscopy to estimate the ability of these inhibitors to attenuate HHE-induced intracellular ONOO(-) levels thus confirming the oxidative mediation of apoptosis in endothelial cells. These findings strongly suggest that accumulated HHE triggers reactive species-mediated endothelial apoptosis, leading to vascular dysfunction as well as vascular aging. During aging, increased lipid peroxidation and its associated production of HHE may exacerbate the weakened redox balance, leading to various chronic degenerative processes including vascular dysfunction. 相似文献
44.
Selection of mRNA 5'-untranslated region sequence with high translation efficiency through ribosome display 总被引:1,自引:0,他引:1
Mie M Shimizu S Takahashi F Kobatake E 《Biochemical and biophysical research communications》2008,373(1):48-52
The 5′-untranslated region (5′-UTR) of mRNAs functions as a translation enhancer, promoting translation efficiency. Many in vitro translation systems exhibit a reduced efficiency in protein translation due to decreased translation initiation. The use of a 5′-UTR sequence with high translation efficiency greatly enhances protein production in these systems. In this study, we have developed an in vitro selection system that favors 5′-UTRs with high translation efficiency using a ribosome display technique. A 5′-UTR random library, comprised of 5′-UTRs tagged with a His-tag and Renilla luciferase (R-luc) fusion, were in vitro translated in rabbit reticulocytes. By limiting the translation period, only mRNAs with high translation efficiency were translated. During translation, mRNA, ribosome and translated R-luc with His-tag formed ternary complexes. They were collected with translated His-tag using Ni-particles. Extracted mRNA from ternary complex was amplified using RT-PCR and sequenced. Finally, 5′-UTR with high translation efficiency was obtained from random 5′-UTR library. 相似文献
45.
We obtained a novel carbohydrate-binding peptide having a helix-loop-helix scaffold from a random peptide library. The helix-loop-helix peptide library randomized at five amino acid residues was displayed on the major coat protein of a filamentous phage. Affinity selection with a ganglioside, Galbeta1-3GalNAcbeta1-4(Neu5Acalpha2-3)Galbeta1-4Glcbeta1-1'Cer (GM1), gave positive phage clones. Surface plasmon resonance spectroscopy showed that a corresponding 35-mer synthetic peptide had high affinity for GM1 with a dissociation constant of 0.24 microM. This peptide preferentially binds to GM1 rather than asialo GM1 and GM2, suggesting that a terminal galactose and sialic acid are required for the binding as for cholera toxin. Circular dichroism spectroscopic studies indicated that a helical structure is important for the affinity and specificity. Furthermore, alanine scanning at randomized positions showed that arginine and phenylalanine play an especially important role in the recognition of carbohydrates. Such a de novo helix-loop-helix peptide would be available for the design of carbohydrate-binding proteins. 相似文献
46.
Fusao Ota Masayuki Yamato Mie Hayashi Masayuki Ota Tetsuro Koga Ahmed Sherin Chiharu Mukai Kentaro Sakai Shigeru Yamamoto 《Microbiological research》2002,157(4):305
Twenty four reference strains (serotype a-h) belonging to the mutans group of streptococci were compared for DNA fragment patterns of rDNA after treatment with Hind III. It was shown that Streptococcus cricetus (serotype a), S. rattus (serotype b), and S. downei (serotype h) reveals comparatively homogeneous patterns while S. mutans (serotype c, e and f) exhibits differences between the different serotypes as well as within single serotypes. S. sobrinus had an intermediary diversity. These data support the previous findings that S. mutans is heterogeneous at the serological, biochemical and genetical level. 相似文献
47.
Thermal modeling of the malignant woman's breast 总被引:3,自引:0,他引:3
In this paper the conceptual three-dimensional model of the normal woman's breast presented in Osman and Afify, is developed into a detailed quantitative model of the malignant woman's breast. This model takes into consideration the effect of tumor size and location on the metabolic heat production, blood perfusion rate, and thermal contour plot of the malignant breast for each tumor size, depth, and location. Also the results of this investigation show that a hot spot in the malignant woman's breast thermal contour plot may not be directly related to an embedded tumor beneath the breast surface. 相似文献
48.
49.
Changes of aliphatic C–H bonds in cyanobacteria during experimental thermal maturation in the presence or absence of silica as evaluated by FTIR microspectroscopy 下载免费PDF全文
Motoko Igisu Tadashi Yokoyama Yuichiro Ueno Satoru Nakashima Mie Shimojima Hiroyuki Ohta Shigenori Maruyama 《Geobiology》2018,16(4):412-428
Aliphatic C–H bonds are one of the major organic signatures detected in Proterozoic organic microfossils, and their origin is a topic of interest. To investigate the influence of the presence of silica on the thermal alteration of aliphatic C–H bonds in prokaryotic cells during diagenesis, cyanobacteria Synechocystis sp. PCC6803 were heated at temperatures of 250–450°C. Changes in the infrared (IR) signals were monitored by micro‐Fourier transform infrared (FTIR) spectroscopy. Micro‐FTIR shows that absorbances at 2,925 cm?1 band (aliphatic CH2) and 2,960 cm?1 band (aliphatic CH3) decrease during heating, indicating loss of the C–H bonds, which was delayed by the presence of silica. A theoretical approach using solid‐state kinetics indicates that the most probable process for the aliphatic C–H decrease is three‐dimensional diffusion of alteration products under both non‐embedded and silica‐embedded conditions. The extrapolation of the experimental results obtained at 250–450°C to lower temperatures implies that the rate constant for CH3 (kCH3) is similar to or lower than that for CH2 (kCH2; i.e., CH3 decreases at a similar rate or more slowly than CH2). The peak height ratio of 2,960 cm?1 band (CH3)/2,925 cm?1 band (CH2; R3/2 values) either increased or remained constant during the heating. These results reveal that the presence of silica does affect the decreasing rate of the aliphatic C–H bonds in cyanobacteria during thermal maturation, but that it does not significantly decrease the R3/2 values. Meanwhile, studies of microfossils suggest that the R3/2 values of Proterozoic prokaryotic fossils from the Bitter Springs Group and Gunflint Formation have decreased during fossilization, which is inconsistent with the prediction from our experimental results that R3/2 values did not decrease after silicification. Some process other than thermal degradation, possibly preservation of specific classes of biomolecules with low R3/2 values, might have occurred during fossilization. 相似文献
50.