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91.
Michal Bista Siglinde Wolf Kareem Khoury Kaja Kowalska Yijun Huang Ewa Wrona Marcelino Arciniega Grzegorz M. Popowicz Tad A. Holak Alexander Dömling 《Structure (London, England : 1993)》2013,21(12):2143-2151
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93.
Angela Ivask Imbi Kurvet Kaja Kasemets Irina Blinova Villem Aruoja Sandra Suppi Heiki Vija Aleksandr K?kinen Tiina Titma Margit Heinlaan Meeri Visnapuu Dagmar Koller Vambola Kisand Anne Kahru 《PloS one》2014,9(7)
The concept of nanotechnologies is based on size-dependent properties of particles in the 1–100 nm range. However, the relation between the particle size and biological effects is still unclear. The aim of the current paper was to generate and analyse a homogenous set of experimental toxicity data on Ag nanoparticles (Ag NPs) of similar coating (citrate) but of 5 different primary sizes (10, 20, 40, 60 and 80 nm) to different types of organisms/cells commonly used in toxicity assays: bacterial, yeast and algal cells, crustaceans and mammalian cells in vitro. When possible, the assays were conducted in ultrapure water to minimise the effect of medium components on silver speciation. The toxic effects of NPs to different organisms varied about two orders of magnitude, being the lowest (∼0.1 mg Ag/L) for crustaceans and algae and the highest (∼26 mg Ag/L) for mammalian cells. To quantify the role of Ag ions in the toxicity of Ag NPs, we normalized the EC50 values to Ag ions that dissolved from the NPs. The analysis showed that the toxicity of 20–80 nm Ag NPs could fully be explained by released Ag ions whereas 10 nm Ag NPs proved more toxic than predicted. Using E. coli Ag-biosensor, we demonstrated that 10 nm Ag NPs were more bioavailable to E. coli than silver salt (AgNO3). Thus, one may infer that 10 nm Ag NPs had more efficient cell-particle contact resulting in higher intracellular bioavailability of silver than in case of bigger NPs. Although the latter conclusion is initially based on one test organism, it may lead to an explanation for “size-dependent“ biological effects of silver NPs. This study, for the first time, investigated the size-dependent toxic effects of a well-characterized library of Ag NPs to several microbial species, protozoans, algae, crustaceans and mammalian cells in vitro. 相似文献
94.
Haslene-Hox H Oveland E Berg KC Kolmannskog O Woie K Salvesen HB Tenstad O Wiig H 《PloS one》2011,6(4):e19217
Major efforts have been invested in the identification of cancer biomarkers in plasma, but the extraordinary dynamic range in protein composition, and the dilution of disease specific proteins make discovery in plasma challenging. Focus is shifting towards using proximal fluids for biomarker discovery, but methods to verify the isolated sample's origin are missing. We therefore aimed to develop a technique to search for potential candidate proteins in the proximal proteome, i.e. in the tumor interstitial fluid, since the biomarkers are likely to be excreted or derive from the tumor microenvironment. Since tumor interstitial fluid is not readily accessible, we applied a centrifugation method developed in experimental animals and asked whether interstitial fluid from human tissue could be isolated, using ovarian carcinoma as a model. Exposure of extirpated tissue to 106 g enabled tumor fluid isolation. The fluid was verified as interstitial by an isolated fluid:plasma ratio not significantly different from 1.0 for both creatinine and Na(+), two substances predominantly present in interstitial fluid. The isolated fluid had a colloid osmotic pressure 79% of that in plasma, suggesting that there was some sieving of proteins at the capillary wall. Using a proteomic approach we detected 769 proteins in the isolated interstitial fluid, sixfold higher than in patient plasma. We conclude that the isolated fluid represents undiluted interstitial fluid and thus a subproteome with high concentration of locally secreted proteins that may be detected in plasma for diagnostic, therapeutic and prognostic monitoring by targeted methods. 相似文献
95.
Hou TY Monk JM Fan YY Barhoumi R Chen YQ Rivera GM McMurray DN Chapkin RS 《The Biochemical journal》2012,442(1):27-37
Newly determined crystal structures of the photosynthetic RC (reaction centre) from two substrains of the non-sulfur purple bacterium Blastochloris viridis strain DSM 133, together with analysis of their gene sequences, has revealed intraspecies evolutionary changes over a period of 14?years. Over 100 point mutations were identified between these two substrains in the four genes encoding the protein subunits of the RC, of which approximately one-fifth resulted in a total of 16 amino acid changes. The most interesting difference was in the M subunit where the change from a leucine residue to glycine in the carotenoid-binding pocket allowed NS5 (1,2-dihydroneurosporene) to adopt a more sterically favoured conformation, similar to the carotenoid conformation found in other related RCs. The results of the present study, together with a high rate of mutations in laboratory bacterial cultures described recently, suggest that bacteria evolve faster than has been generally recognized. The possibility that amino acid changes occur within protein sequences, without exhibiting any immediately observable phenotype, should be taken into account in studies that involve long-term continuous growth of pure bacterial cultures. The Blc. viridis RC is often studied with sophisticated biophysical techniques and changes such as those described here may well affect their outcome. In other words, there is a danger that laboratory-to-laboratory variation could well be due to different groups not realising that they are actually working with slightly different proteins. A way around this problem is suggested. 相似文献
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98.
Ishfaq A. Sheikh Rola F. Turki Adel M. Abuzenadah Ghazi A. Damanhouri Mohd A. Beg 《PloS one》2016,11(3)
Phthalates are a class of high volume production chemicals used as plasticizers for household and industrial use. Several members of this chemical family have endocrine disrupting activity. Owing to ubiquitous environmental distribution and exposure of human population at all stages of life, phthalate contamination is a continuous global public health problem. Clinical and experimental studies have indicated that several phthalates are associated with adverse effects on development and function of human and animal systems especially the reproductive system and exposures during pregnancy and early childhood are by far of utmost concern. Sex hormone-binding globulin (SHBG) is a plasma carrier protein that binds androgens and estrogens and represents a potential target for phthalate endocrine disruptor function in the body. In the present study, the binding mechanism of the nine phthalates i.e. DMP, DBP, DIBP, BBP, DNHP, DEHP, DNOP, DINP, DIDP with human SHBG was delineated by molecular docking simulation. Docking complexes of the nine phthalates displayed interactions with 15–31 amino acid residues of SHBG and a commonality of 55–95% interacting residues between natural ligand of SHBG, dihydrotestosterone, and the nine phthalate compounds was observed. The binding affinity values were more negative for long chain phthalates DEHP, DNOP, DINP, and DIDP compared to short chain phthalates such as DMP and DBP. The Dock score and Glide score values were also higher for long chain phthalates compared to short chain phthalates. Hence, overlapping of interacting amino acid residues between phthalate compounds and natural ligand, dihydrotestosterone, suggested potential disrupting activity of phthalates in the endocrine homeostasis function of SHBG, with long chain phthalates expected to be more potent than the short chain phthalates. 相似文献
99.
Kelly Fishman Jennifer Baure Yani Zou Ting-Ting Huang Marta Andres-Mach Radoslaw Rola Tatiana Suarez Munjal Acharya Charles L. Limoli Kathleen R. Lamborn John R. Fike 《Free radical biology & medicine》2009,47(10):1459-1467
Ionizing irradiation significantly affects hippocampal neurogenesis and is associated with cognitive impairments; these effects may be influenced by an altered microenvironment. Oxidative stress is a factor that has been shown to affect neurogenesis, and one of the protective pathways that deal with such stress involves the antioxidant enzyme superoxide dismutase (SOD). This study addressed what impact a deficiency in cytoplasmic (SOD1) or mitochondrial (SOD2) SOD has on radiation effects on hippocampal neurogenesis. Wild-type (WT) and SOD1 and SOD2 knockout (KO) mice received a single X-ray dose of 5 Gy, and quantification of the survival and phenotypic fate of newly generated cells in the dentate subgranular zone was performed 2 months later. Radiation exposure reduced neurogenesis in WT mice but had no apparent effect in KO mice, although baseline levels of neurogenesis were reduced in both SOD KO strains before irradiation. Additionally, there were marked and significant differences between WT and both KO strains in how irradiation affected newly generated astrocytes and activated microglia. The mechanism(s) responsible for these effects is not yet known, but a pilot in vitro study suggests a “protective” effect of elevated levels of superoxide. Overall, these data suggest that under conditions of SOD deficiency, there is a common pathway dictating how neurogenesis is affected by ionizing irradiation. 相似文献
100.
Alejandro A Diaz Farbod N Rahaghi James C Ross Rola Harmouche Juerg Tschirren Raul San José Estépar George R Washko for the COPD Gene investigators 《Respiratory research》2015,16(1)