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151.
Chang VT Crispin M Aricescu AR Harvey DJ Nettleship JE Fennelly JA Yu C Boles KS Evans EJ Stuart DI Dwek RA Jones EY Owens RJ Davis SJ 《Structure (London, England : 1993)》2007,15(3):267-273
Glycoproteins present special problems for structural genomic analysis because they often require glycosylation in order to fold correctly, whereas their chemical and conformational heterogeneity generally inhibits crystallization. We show that the "glycosylation problem" can be solved by expressing glycoproteins transiently in mammalian cells in the presence of the N-glycosylation processing inhibitors, kifunensine or swainsonine. This allows the correct folding of the glycoproteins, but leaves them sensitive to enzymes, such as endoglycosidase H, that reduce the N-glycans to single residues, enhancing crystallization. Since the scalability of transient mammalian expression is now comparable to that of bacterial systems, this approach should relieve one of the major bottlenecks in structural genomic analysis. 相似文献
152.
Tatiana Dumitra Panaite Petru Alexandru Vlaicu Mariana Ropota Alexandru Radu Corbu Mihaela Saracila 《Archives of animal nutrition》2019,73(3):222-238
The aim of this study was to investigate the effects of simultaneous supplementation of laying hens with dietary sources of n-3 polyunsaturated fatty acids (PUFA) and carotenoids on egg quality, fatty acids and carotenoid profile of the egg yolk and on feed and yolk lipid peroxidation. A 6-week experiment was carried out with 53-week old laying hens (96 Tetra SL) assigned to a control and three treatment groups supplemented with 5% flaxseeds and different levels of dried tomato waste (DTW, 2.5%, 5.0% and 10.0%). Hens from the groups supplemented with 5% and 7.5% DTW had a significantly lower average daily feed intake and laying percentage as compared to the control. Increased doses of dietary DTW enhanced yolk Roche colour score in direct correlation with the enrichment of egg yolk in carotenoids but decreased their transfer efficiency from feed to egg. After 4 weeks, egg yolk from hens fed with 5% flaxseeds and 7.5% DTW had increased lutein and zeaxanthin levels (by 29% and 24%, respectively) and the colour score was 3.5 fold higher compared to the control group. As a result of the dietary supplementation with flaxseed, the n-3 fatty acid content was 3.1–3.7-fold higher in egg yolk compared with the control and the n-6/n-3 ratio decreased from 18.3 (control) to 4.1–5.4 in supplemented diets. Dietary supplementation with 5% DTW effectively prevented lipid oxidation of eggs enriched with n-3 PUFA, but the increase in DTW content depressed the absorption and deposition of n-3 PUFA in egg yolk. 相似文献
153.
Veronica Ionela Moroeanu Emanuel Vamanu Gabriela Paun Elena Neagu Oana Rodica Ungureanu Sandra A. V. Eremia Gabriel-Lucian Radu Robertina Ionescu Diana Roxana Pelinescu 《Indian journal of microbiology》2015,55(4):423-429
The main goal of our study was to evaluate the effect of the individual administration of five lyophilized lactic acid bacteria strains (Lactobacillus fermentum 428ST, Lactobacillus rhamnosus E4.2, Lactobacillus plantarum FCA3, Lactobacillus sp. 34.1, Weissella paramesenteroides FT1a) against the in vitro simulated microbiota of the human colon using the GIS1 system. The influence on the metabolic activity was also assessed by quantitative determination of proteins and polysaccharides at each segment of human colon. The obtained results indicated that the lactic acid bacteria L. rhamnosus E4.2 and W. paramesenteroides FTa1 had better efficiency in synthesising exopolysaccharides and also a better probiotic potential and therefore could be recommended for use in probiotics products or food industry. 相似文献
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Denisa Hathazi Sonia Diana Mahuţ Florina-Violeta Scurtu Cristina Bischin Corina Stanciu Amr Ali Attia Grigore Damian Radu Silaghi-Dumitrescu 《Journal of biological inorganic chemistry》2014,19(7):1233-1239
The reaction between nitrite and the oxy forms of globins has complex autocatalytic kinetics with several branching steps and evolves through chain reactions mediated by reactive species (including radicals) such as hydrogen peroxide, ferryl and nitrogen dioxide, starting with a lag phase, after which it proceeds onto an autocatalytic phase. Reported here are UV–Vis spectra collected upon stopped-flow mixing of myoglobin with a supraphysiological excess of nitrite. The best fit to the experimental data follows an A → B → C reaction scheme involving the formation of a short-lived intermediate identified as ferryl. This is consistent with a mechanism where nitrite binds to oxy myoglobin to generate an undetectable ferrous-peroxynitrate intermediate, whose decay leads to nitrate and ferryl. The ferryl is then reduced to met by the excess nitrite. DFT calculations reveal an essentially barrierless reaction between nitrite and the oxy heme, with a notable outer-sphere component; the resulting metastable ferrous-peroxynitrate adduct is found to feature a very low barrier towards nitrate liberation, with ferryl as a final product—in good agreement with experiment. 相似文献
157.
Tara Chestnut Chauncey Anderson Radu Popa Andrew R. Blaustein Mary Voytek Deanna H. Olson Julie Kirshtein 《PloS one》2014,9(9)
Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L−1. The highest density observed was ∼3 million zoospores L−1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free-living Bd in aquatic habitats over time. 相似文献
158.
Three different variants of photoactivatable caged paclitaxel (PTX) have been synthesized and their bioactivity was characterized in in vitro assays and in living cells. The caged PTXs contain the photoremovable chromophore 4,5-dimethoxy-2-nitrobenzyloxycarbonyl (Nvoc) attached to position C7, C2' and to both of these positions via a carbonate bond. Single caged PTXs remained biologically active even at low dosages. Double caging was necessary in order to fully inhibit its activity and to obtain a phototriggerable PTX that can be applied successfully at commonly used concentrations. Irradiation of solutions containing the double caged PTX allowed dose-dependent delivery of functional PTX. Light-triggered stabilization of microtubule assemblies in vitro and in vivo by controlled light exposure of tubulin solutions or cell cultures containing caged PTX was demonstrated. Short light exposure under a fluorescence microscope allowed controlled delivery of free PTX during imaging. 相似文献
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