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451.
Dinsmore AD Hsu MF Nikolaides MG Marquez M Bausch AR Weitz DA 《Science (New York, N.Y.)》2002,298(5595):1006-1009
We present an approach to fabricate solid capsules with precise control of size, permeability, mechanical strength, and compatibility. The capsules are fabricated by the self-assembly of colloidal particles onto the interface of emulsion droplets. After the particles are locked together to form elastic shells, the emulsion droplets are transferred to a fresh continuous-phase fluid that is the same as that inside the droplets. The resultant structures, which we call "colloidosomes," are hollow, elastic shells whose permeability and elasticity can be precisely controlled. The generality and robustness of these structures and their potential for cellular immunoisolation are demonstrated by the use of a variety of solvents, particles, and contents. 相似文献
452.
Wang X Wu YC Fadok VA Lee MC Gengyo-Ando K Cheng LC Ledwich D Hsu PK Chen JY Chou BK Henson P Mitani S Xue D 《Science (New York, N.Y.)》2003,302(5650):1563-1566
During apoptosis, phosphatidylserine, which is normally restricted to the inner leaflet of the plasma membrane, is exposed on the surface of apoptotic cells and has been suggested to act as an "eat-me" signal to trigger phagocytosis. It is unclear how phagocytes recognize phosphatidylserine. Recently, a putative phosphatidylserine receptor (PSR) was identified and proposed to mediate recognition of phosphatidylserine and phagocytosis. We report that psr-1, the Caenorhabditis elegans homolog of PSR, is important for cell corpse engulfment. In vitro PSR-1 binds preferentially phosphatidylserine or cells with exposed phosphatidylserine. In C. elegans, PSR-1 acts in the same cell corpse engulfment pathway mediated by intracellular signaling molecules CED-2 (homologous to the human CrkII protein), CED-5 (DOCK180), CED-10 (Rac GTPase), and CED-12 (ELMO), possibly through direct interaction with CED-5 and CED-12. Our findings suggest that PSR-1 is likely an upstream receptor for the signaling pathway containing CED-2, CED-5, CED-10, and CED-12 proteins and plays an important role in recognizing phosphatidylserine during phagocytosis. 相似文献
453.
Serums of patients with intracranial meningiomas reacted in immunofluorescence assays with cell cultures and tumor imprints prepared from human meningiomas. Antibody in these serums appears to be specific for antigens in meningioma tissue and shows some cross-reactivity with neoplastic tissue of glial origin. 相似文献
454.
Dillin A Hsu AL Arantes-Oliveira N Lehrer-Graiwer J Hsin H Fraser AG Kamath RS Ahringer J Kenyon C 《Science (New York, N.Y.)》2002,298(5602):2398-2401
To explore the role of mitochondrial activity in the aging process, we have lowered the activity of the electron transport chain and adenosine 5'-triphosphate (ATP) synthase with RNA interference (RNAi) in Caenorhabditis elegans. These perturbations reduced body size and behavioral rates and extended adult life-span. Restoring messenger RNA to near-normal levels during adulthood did not elevate ATP levels and did not correct any of these phenotypes. Conversely, inhibiting respiratory-chain components during adulthood only did not reset behavioral rates and did not affect life-span. Thus, the developing animal appears to contain a regulatory system that monitors mitochondrial activity early in life and, in response, establishes rates of respiration, behavior, and aging that persist during adulthood. 相似文献
455.
Chemical bioinduction of rubber in guayule plant 总被引:1,自引:0,他引:1
The treatment of young guayule plants with 2-(3,4-dichlorophenoxy)-triethylamine stimulated the accumulation of polyisoprenoid rubber in the stem and root tissues. This finding suggests that rubber productivity can be improved by the use of chemical agents on guayule and other rubber-forming plants. 相似文献
456.
This study used recycled fibers and inflaming retarding fibers to form composite nonwoven and then compounded with PU foam preparing composite board with sound-absorbing, thermal-insulating and cushion properties. Effects of foam density and composite nonwoven on three properties of PU composite board have studied. Result shows that, with increase of foam density, composite boards had higher sound absorbing coefficient at medium and high frequencies, lower thermal insulation as well as firstly improved and then decreased cushion property. After assessment, the optimal foam density was 60 kg/m3. For diverse requirements, PU foam matches with different kinds of composite nonwoven to achieve excellent cushion property. The resulting composite board can effectively ease hurts from rigid wall, and could be applied in kindergarten, music hall, audio-visual room, pub and recreational centre etc in the future. 相似文献
457.
Breadfruit (Artocarpus communis Moraceae) is cultivated in tropical and subtropical regions as a traditional starch crop and also has potential medicinal properties. The aim of this work was to study the in vitro anticancer activity of compounds isolated from the leaves of Artocarpus communis. Three new geranyl chalcone derivatives including isolespeol (1), 5'-geranyl-2',4',4-trihydroxychalcone (2), and 3,4,2',4'-tetrahydroxy-3'-geranyldihydrochalcone (3), together with two known compounds lespeol (4) and xanthoangelol (5), were isolated from the leaves of Artocarpus communis. The structures of 1- 5 were elucidated by spectroscopy and through comparison with data reported in the literature. The effects of geranyl chalcone derivatives (1- 5) on the viability of human cancer cells (including SW 872, HT-29, COLO 205, Hep3B, PLC5, Huh7, and HepG2 cells) were investigated. The results indicate that isolespeol (1) showed the highest inhibitory activity with an IC 50 value of 3.8 muM in SW 872 human liposarcoma cells. Treatment of SW 872 human liposarcoma cells with isolespeol (1) caused the loss of mitochondrial membrane potential (DeltaPsim). Western blotting revealed that isolespeol (1) stimulated increased protein expression of Fas, FasL, and p53. The expression ratios of pro- and antiapoptotic Bcl-2 family members were also changed by isolespeol (1) treatment to subsequently induce the activation of caspase-9 and caspase-3, which was followed by cleavage of poly (ADP-ribose) polymerase (PARP). These results demonstrate that isolespeol (1) induces apoptosis in SW 872 cells through Fas- and mitochondria-mediated pathways. 相似文献
458.
Daniel H. Buckley Varisa Huangyutitham Shi-Fang Hsu Tyrrell A. Nelson 《Soil biology & biochemistry》2008,40(6):1272-1283
Nucleic acid stable isotope probing (SIP) is a powerful tool that can identify and characterize the microorganisms that mediate specific soil processes and explore the flow of C and N through functional groups in the soil food web. While 13C–SIP has been used successfully in a range of applications, methodological constraints have limited the applicability of 15N-labelled compounds in nucleic acid SIP. However, 15N–DNA–SIP can now be achieved and this method when used with 15N2 provides a powerful new tool for characterizing free-living diazotrophs in natural ecosystems. A diverse array of non-cultivated diazotrophs have been observed in soil and yet the characteristics of these organisms and their environmental significance remain almost completely unknown. 15N2–DNA–SIP can identify those diazotrophs that are active in situ while providing access to gene sequences and genome fragments that can yield insights on their evolutionary history and functional capacities. Further insights on the ecology of free-living diazotrophs in soil can be provided by performing 15N2–DNA–SIP on microcosms in which the response of the diazotrophic community is determined in relation to experimental manipulation. We describe the use of 15N2–DNA–SIP to explore linkages between different C sources and N-fixation by specific diazotroph populations in soil. Methane addition to soil was observed to stimulate N-fixation and the organisms that were found to be responsible for this activity were Type II methanotrophs most closely related to the genus Methylocystis. This report provides insights on the use of nucleic acid SIP to identify and characterize microorganisms that mediate specific soil processes and represents the first time that a specific group of methanotrophs has been shown to mediate N-fixation while in the soil environment. 相似文献
459.
Luteolin ameliorates experimental lung fibrosis both in vivo and in vitro: implications for therapy of lung fibrosis 总被引:1,自引:0,他引:1
Chen CY Peng WH Wu LC Wu CC Hsu SL 《Journal of agricultural and food chemistry》2010,58(22):11653-11661
Lonicera japonica (Caprifoliaceae) has been known as an anti-inflammatory herb in traditional Chinese medicine for thousands of years and is used constantly for upper respiratory tract infections. Luteolin, an active flavonoid compound isolated from Lonicera japonica, has a spectrum of biological activities, especially with antioxidative and anti-inflammatory properties. However, whether luteolin has a direct inhibitory effect on lung fibrosis has not been established. In this study, we examined the effects of luteolin on lung fibrosis both in vivo and in vitro. We found that oral administration of luteolin (10 mg/kg) efficiently suppressed the neutrophil infiltration as well as TNF-α and IL-6 elevation in the bronchoalveolar lavage fluid in bleomycin-instilled C57BL/6J mice. Luteolin also alleviated collagen deposition, TGF-β1 expression, and lung fibrosis upon bleomycin instillation. A similar tendency was observed in both early and delayed luteolin-treated groups. Next, our in vitro studies showed that luteolin inhibited TGF-β1-induced α-SMA, type I collagen, and vimentin expression in primary cultured mouse lung fibroblasts. Moreover, luteolin significantly blocked TGF-β1-mediated epithelial marker (E-cadherin) downregulation and mesenchymal cell markers (fibronectin and vimentin) upregulation, as well as retaining epithelial morphology in human alveolar epithelial-derived A549 cells. Additionally, luteolin could attenuate TGF-β1-induced Smad3 phosphorylation in both lung fibroblasts and A549 cells. These findings suggest that luteolin has a potent antifibrotic activity; this effect was mediated, at least in part, by inhibition of lung inflammation and suppression of myofibroblast differentiation as well as epithelial-to-mesenchymal transition. 相似文献
460.
Hua KF Hsu HY Su YC Lin IF Yang SS Chen YM Chao LK 《Journal of agricultural and food chemistry》2006,54(2):306-311
Methanolic extracts from the seagrass Zostera japonica were extracted successively using n-hexane (n-C(6)H(14)), dichloromethane (CH(2)Cl(2)), ethyl acetate (EtOAc), and water to give the n-C(6)H(14) (16.8%), CH(2)Cl(2) (40.6%), EtOAc (34.1%), and H(2)O (8.5%) soluble fractions, respectively. We have demonstrated that the hexane fraction has the highest capacity to inhibit proIL-1beta expression as compared to other fractions in lipopolysaccharides (LPS)-stimulated J774A.1 murine macrophages. Further analysis of the composition and antiinflammatory activity of the subfraction H5 from hexane fraction showed that it had the best antiinflammatory capacity and that it's major constituents were fatty acids, including palmitic acid methyl ester (21.5%), palmitic acid (24.02%), linoleic acid methyl ester (13.09%), oleic acid methyl ester (8.41%), and linoleic acid (7.93%), respectively. H5 inhibited LPS-induced TNFalpha, IL-1beta, and IL-6 in a dose-dependent manner, suggesting that H5 is bioactive in antiinflammation in vitro. This study is the first to report the antiinflammatory activity of extracts obtained from the seagrass Z. japonica. 相似文献