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21.
《Free radical research》2013,47(6):323-327
Breath analysis is a non-invasive method for investigation of the volatile compounds produced by humans. Pentane has often been taken as an indicator of lipid peroxidation. Our purpose in this study was to determine its normal concentration in the breath of healthy humans. Using a specific and sensitive gas chromatography-mass spectrometry technique pentane concentrations in breath were lower than 10 pmoles/1. The high levels of pentane found by some authors in healthy humans were probably due to the coelution of pentane with isoprene, a volatile hydrocarbon present in human breath. 相似文献
22.
B. J. B. Wood P. H. K. Grimson J. B. German M. Turner 《Journal of biotechnology》1999,70(1-3):175-183
Interest is growing in algae as sources of medicinal and other potentially useful compounds, as well as their use in fish rearing. We are interested in their production of polyunsaturated fatty acids (PUFA). Photoautotrophic growth gives the highest levels of unsaturation in the fatty acid pool, but biomass concentrations are low. Heterotrophy on sugars gives higher biomass but seems to give more saturation in the fatty acids. In freshwater algae acetate has proved to be a good carbon source for photoheterotrophic growth, giving a crop with reasonably high levels of PUFA. In addition it is possible to regulate acetic acid addition through the pH change as acetate is used up in a well-aerated system, so achieving high biomass yields in the presence of relatively low acetate concentration. When we attempted to extend this to marine algae (principally species used in fish farming), we found that acetic acid was ineffective or sometimes toxic to most species tested, even at high pH. However, glycerol stimulated growth in a number of the algae. We report on this stimulation, and on the fatty acid composition of the resulting algal crop, discuss the problems in regulating the addition of this metabolite to algal cultures, and speculate on applications in the production of other useful algal metabolites. We also show that some of these algae used in fish farming grow best when the salinity of the water is rather less than that found in standard sea water. 相似文献
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24.
C6 glioma cells were stimulated with the beta-adrenergic agonist isoproterenol. The rate of cyclic AMP accumulation and lipid methylation increased. However, the elevated rate of lipid methylation did not affect the fluidity of the plasma membrane. It is concluded that lipid methylation is not responsible for making the plasma membrane more fluid during the beta-adrenergic response. 相似文献
25.
Changes in total nitrogen, soluble amino nitrogen, lipid and phytate contents, and in the activities of proteinase (pH 7.0), isocitrate lyase and phytase were followed in the endosperm, cotyledons, and axis during germination of fenugreek seeds and subsequent growth of the seedlings. The endosperm is comprised largely of cell-wall galactomannans: the majority of the seed total nitrogen, lipid and phytate (5%, 8%, 0.44% of seed dry weight respectively) is localised within the cotyledons as stored reserves. Germination is completed after 10–14 h from the start of imbibition, but the major reserves are not mobilised during the first 24 h. Then the total nitrogen content of the cotyledons starts to decrease and that of the axis increases; there is a concomitant accumulation of soluble amino nitrogen in both cotyledons and axis. An increase in proteinase activity in the cotyledons correlates well with the depletion of total nitrogen therein. Depletion of lipid and phytate reserves in the different seed tissues constitutes a late event, occurring after 50 h from the start of imbibition, and is coincident with the final disintegration of the endosperm tissue. The depletion of phytate and stored lipids is accompanied by an increase in phytase and isocitrate lyase activity. It appears that the products of lipid hydrolysis are converted by gluconeogenesis to serve as the major source of sugars for the growing axis after the endosperm galactomannan has been completely mobilised. 相似文献
26.
The outer membrane (OM) of Gram-negative bacteria exhibits unique lipid asymmetry that makes it an effective permeability barrier against toxic molecules, including antibiotics. Central to the maintenance of OM lipid asymmetry is the OmpC-Mla (maintenance of lipid asymmetry) system, which mediates the retrograde transport of phospholipids from the outer leaflet of the OM to the inner membrane. The molecular mechanism(s) of this lipid trafficking process is not fully understood; however, recent advances in structural elucidations and biochemical reconstitutions have provided detailed new insights. Here, we present an integrated understanding of how the OmpC-Mla system transports mislocalized phospholipids across the bacterial cell envelope. 相似文献
27.
《Saudi Journal of Biological Sciences》2022,29(3):1842-1852
The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H2O2 (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H2O2. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H2O2 only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress. 相似文献
28.
Advancements in chemical proteomics and mass spectrometry lipidomics are providing new opportunities to understand lipid kinase activity, specificity, and regulation on a global cellular scale. Here, we describe recent developments in chemical biology of lipid kinases with a focus on those members that phosphorylate diacylglycerols. We further discuss future implications of how these mass spectrometry–based approaches can be adapted for studies of additional lipid kinase members with the aim of bridging the gap between protein and lipid kinase–focused investigations. 相似文献
29.
Li Shichang Zhang Pengpeng Gu Shaobin Liu Hongxia Liu Ya Liu Shengnan 《Indian journal of microbiology》2013,53(3):343-351
In order to obtain lipid producing strain with high-yield, the wild type stain Rhodotorula glutinis was treated by low ion implantation, and optimization of fermentation medium for higher lipid yield was carried out using mutant strain. It was found that the strain had a higher positive mutation rate when the output power was 10 keV and the dose of N+ implantation was 80 × 2.6 × 1013 ions/cm2. Then a high-yield mutant strain D30 was obtained through cid-heating coupling ultrasonic method and lipid yield was 3.10 g/L. Additionally, the surface response method was used to optimize fermentation medium. The three significant factors (glucose, peptone, KH2PO4) were optimized using response surface methodology (RSM), and the optimized parameters of fermentation medium were as follows: glucose 73.40 g/L, peptone 1.06 g/L and KH2PO4 3.56 g/L. Finally the fermentation characteristic of high-yield mutation strain D30 was studied, when fermentation time was 10 days, which lipid yield increased to 7.81 g/L. Fatty acid composition of the lipid was determined by GC, and the most represented fatty acids of mutant D30 were C16:0 (11.4 %), C16:1 (5.66 %), C18:1 (49.3 %), and C18:2 (27.0 %). 相似文献
30.
Maria Pia Rigobello Guido Scutari Rita Boscolo Alberto Bindoli 《Free radical research》2013,47(10):1071-1077
The antioxidant properties of S -nitrosoglutathione, a nitric oxide-derived product were studied in different experimental systems. By using the crocin bleaching test, S -nitrosoglutathione, in the presence of copper ions, shows an antioxidant capacity about six times higher than that of Trolox c and referable to the interception of peroxyl radicals by nitric oxide. Copper alone shows a modest inhibitory action, which is about seven times lower than that of Trolox c. S -nitrosoglutathione prevents lipid peroxidation induced by the well-known Fe 2+ /ascorbate system (IC 50 =450 w M) and the inhibitory effect is strongly reinforced by the presence of copper ions (IC 50 =6.5 w M). In addition, cumene hydroperoxide-induced lipid peroxidation is markedly decreased by S -nitrosoglutathione, provided that copper ions, maintained reduced by ascorbate, are present. Decomposition of S -nitrosoglutathione through metal catalysis and/or the presence of reducing agents and the consequent release of nitric oxide are of crucial importance for eliciting the antioxidant power. In this way, copper ions and/or reducing species with low antioxidant potency are able to promote the formation of an extremely strong antioxidant species such as nitric oxide. 相似文献