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排序方式: 共有1194条查询结果,搜索用时 31 毫秒
71.
对海洋中筛选的酒香酵母(Brettanomyces sp.)7-3产DHA条件进行了优化,结果表明培养基最佳组成为葡萄糖10 g/L, 蔗糖10 g/L,酵母膏20 g/L,(NH4)2SO4 10 g/L,NaHCO3 1 g/L,K2HPO4 6 g/L,ZnSO4 0.1 g/L,MgSO4 0.1 g/L,CaCl2 0.5 g/L,Na2EDTA 0.2 g/L,FeC6H5O7·3H2O 0.01 g/L.摇瓶培养最佳条件为培养初始pH=6.0,培养温度25 ℃,装液量为100 mL(在500 mL摇瓶中),培养时间为84 h,优化后油脂与DHA产量分别提高了3.3和3.8倍. 相似文献
72.
Quantification of Protein‐Induced Membrane Remodeling Kinetics In Vitro with Lipid Multilayer Gratings
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Troy W. Lowry Plengchart Prommapan Aubrey Kusi‐Appiah Nicholas Vafai Ewa A. Bienkiewicz David H. Van Winkle Scott M. Stagg Steven Lenhert 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(4):506-515
The dynamic self‐organization of lipids in biological systems is a highly regulated process that enables the compartmentalization of living systems at micro‐ and nanoscopic scales. Consequently, quantitative methods for assaying the kinetics of supramolecular remodeling such as vesicle formation from planar lipid bilayers or multilayers are needed to understand cellular self‐organization. Here, a new nanotechnology‐based method for quantitative measurements of lipid–protein interactions is presented and its suitability for quantifying the membrane binding, inflation, and budding activity of the membrane‐remodeling protein Sar1 is demonstrated. Lipid multilayer gratings are printed onto surfaces using nanointaglio and exposed to Sar1, resulting in the inflation of lipid multilayers into unilamellar structures, which can be observed in a label‐free manner by monitoring the diffracted light. Local variations in lipid multilayer volume on the surface is used to vary substrate availability in a microarray format. A quantitative model is developed that allows quantification of binding affinity (K D) and kinetics (kon and koff). Importantly, this assay is uniquely capable of quantifying membrane remodeling. Upon Sar1‐induced inflation of single bilayers from surface supported multilayers, the semicylindrical grating lines are observed to remodel into semispherical buds when a critical radius of curvature is reached. 相似文献
73.
In several termite species, distinct differences in the composition of cuticular hydrocarbons among colonies correspond to
high genetic divergence of mitochondrial DNA sequences. These observations suggest that hydrocarbon phenotypes represent cryptic
species. Different cuticular hydrocarbon phenotypes also are found among colonies of fungus-growing termites of the genus
Macrotermes. To determine if these hydrocarbon differences in Macrotermes also indicate cryptic species, we sequenced the mitochondrial CO I gene from species in West and East Africa. Among individuals
of a supposed species but belonging to different cuticular hydrocarbon phenotypes, the genetic distances are much smaller
than distances between species. Unlike what has been observed in other termites, Macrotermes hydrocarbon phenotypes do not represent cryptic species. Our findings suggest fundamental differences in the evolution and/or
function of cuticular hydrocarbons among different termite lineages.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
74.
H. J. YARDLEY 《International journal of cosmetic science》1987,9(1):13-19
From the time an epidermal cell leaves the basal layer to the time it is desquamated, the cell lipids change dramatically, both qualitatively and quantitatively. The most abundant lipid class in basal cells is phospholipid with the remaining lipid being accounted for by roughly equal proportions of cholesterol, non-esterified fatty acid, triacylglycerol and glycolipid: minor components include cholesteryl esters and ceramide. In contrast, approximately half of the lipid in a desquamated cell consists of ceramide, with the remainder consisting largely of cholesterol and non-esterified fatty acid. Immediately before desquamation, small concentrations of cholesteryl sulphate and glycolipid have been found and there is evidence that these polar lipids are important components of the water barrier and also contribute towards the physical integrity of the lower part of the stratum corneum. The change in lipid content as cornification proceeds is no less dramatic than the change in lipid composition. A basal cell contains about 10 pg lipid, whereas a desquamated stratum corneum cell contains approximately six times this amount. The change in lipid composition of a cell undergoing cornification results, therefore, largely from de novo synthesis of lipid, especially cholesterol, non-esterified fatty acid and ceramide.
Les lipides de l'épiderme 相似文献
Les lipides de l'épiderme 相似文献
75.
Intidhar Bouali Hajer Trabelsi Ikram Bou Abdallah Ali Albouchi Lucy Martine Stéphane Grégoire Ghaith Bouzaien Mhemmed Gandour Sadok Boukhchina Olivier Berdeaux 《Journal of the American Oil Chemists' Society》2013,90(12):1869-1876
Among oil compounds, fatty acids, tocopherols and xanthophylls (lutein and zeaxanthin) are of special interest due to their nutritional properties. The identification and quantification of these compounds in pecan nuts (Carya illinoinensis) could therefore be very useful to produce functional foods rich in compounds of this type. This paper reports studies on their accumulation and the effect of ripening on the content of these high value-added compounds. The total lipid content increased during the ripening. Saturated and polyunsaturated fatty acids decreased significantly, whereas, monounsaturated fatty acids increased during the ripening of pecan nut fruit. Maximum levels of total tocopherol (279.53 mg/kg oil) and xanthophyll (6.18 mg/kg oil) were detected at 20th weeks after the flowering date. These amounts decreased gradually as ripening advances. The early stages of pecan ripening seem to have nutritional and pharmaceutical interests. These results may be useful for evaluating the pecan nut quality and determining the optimal period when the pecans accumulated the maximum of these nutritional and healthy compounds. 相似文献
76.
Santiago P. Aubourg Vanesa Losada & Ricardo Prego 《International Journal of Food Science & Technology》2007,42(12):1456-1464
Lipid and trace mineral composition were studied in different sites of the edible flesh of farmed and wild turbot (Psetta maxima). Lipid matter (total content, sterols, tocopherols) showed to accumulate in the edge zone (EZ), except for phospholipid (PL), which provided a distribution that was found to be independent from the kind of turbot and the zone considered. Fatty acid composition of total lipids showed a non‐homogeneous distribution, as the EZ exhibited a different fatty acid group composition (higher monounsaturated and lower polyunsaturated and ω3/ω6 ratio values) than the other zones considered; fewer differences were observed by considering the PL fatty acid composition. Most minerals (Ca, Cu, Fe, Mn and Se) studied showed to be homogeneously distributed along the muscle sites of the wild fish, while more differences were obtained when considering the farmed one. For both kinds of turbots, the most important difference was obtained in the case of Zn, as a largely higher content in the EZ than in the other zones was detected. A close relationship between Zn and total lipid contents (r2 = 0.90 and 0.76 for farmed and wild turbots, respectively) was observed. 相似文献
77.
Alok K. Hazra Somiranjan Ghosh Shivaji Banerjee Biswapati Mukherjee 《Journal of the American Oil Chemists' Society》1998,75(11):1673-1678
The puffer fishes Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris, and L. inermis of Indian coastal waters are wasted in huge quantity. The livers of these fishes were investigated for their lipid contents
and fatty acid compositions in different seasons. It was found that monsoon season is the suitable time to obtain the maximal
lipids (40.1–48.8%) from their livers, an amount similar to cod liver lipid content (39.5–55.0%). The fatty acids were mostly
saturates and monoenes (60–70%). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations (7–12%) were high
during monsoon season. Neutral lipids were the predominant lipid class (>80%) and comprised triglycerides (277–674 mg/g) and
cholesterol (0.6–3.1 mg/g). Quality indices of puffer liver lipids, e.g., specific gravity, refractive index, acid value,
iodine value, saponification value and unsaponifiable matter, were evaluated. Puffer liver lipids were quantitatively and
qualitatively comparable to other commercially important marine fish oils. The overall study suggests the possibility of future
commercial utilization of liver lipids from puffer, an unconventional, cheap, and easily available source. 相似文献
78.
神经酰胺脂质体——含角质层脂质膜的脂质体 总被引:4,自引:0,他引:4
角质层的渗透屏障大多是由饱和脂质如神经酰胺、胆固醇和游离脂肪酸组成。它是物质交换的有效阻隔并防止皮肤干燥。神经酰胺脂质体(Cerasomes)是一种脂质体,它的膜是由最重要的角质层脂质组成的。神经酰胺脂质体作为类皮肤膜的来源,它能加快受损屏障层的再生、降低皮肤刺激,并且它还提供了将角质层脂质应用于化妆品中简单而有效的途径。 相似文献
79.
Niall W. G. Young Paul Wassell Johan Wiklund Mats Stading 《International Journal of Food Science & Technology》2008,43(11):2083-2089
Ultrasonic velocity profiling with pressure difference (UVP‐PD) was demonstrated to be a successful, non‐invasive, in‐line measurement system for instantaneous velocity and rheological flow profiling of complex, opaque fat blends. Model systems of 25% Akomic, 75% rapeseed oil; and 25% Akomic, 74% rapeseed oil and 1% Grindsted® Crystalliser 110 were compared under real process conditions with UVP‐PD. Results indicated that the sample containing the crystalliser had twice the viscosity of the control. These in‐line results are in agreement with previous off‐line results, and offer the chance to probe the mechanics of fat blend physics under real, dynamic conditions. 相似文献
80.
Robert L. Wolff Frédérique Pédrono Anne M. Marpeau William W. Christie Frank D. Gunstone 《Journal of the American Oil Chemists' Society》1998,75(11):1637-1641
The fatty acid compositions of the seeds from three Taxus (yew) species and one Torreya species belonging to the Taxaceae family [Taxus cuspidata (Japanese yew), T. chinensis (Chinese yew), T. baccata (English yew), and Torreya grandis (Chinese nutmeg yew)] have been established. These compositions were compared with those previously published for T. canadensis (Canadian yew) and Torreya nucifera. In Taxus species, as well as in Torreya species, Δ5-olefinic acids are present in the seed lipids from all species analyzed. In Taxus, 5,9-18:2 (taxoleic) acid is the prominent Δ5-olefinic acid. It represents between 9.5 and 16.2% of total fatty acids. Other
Δ5-olefinic acids that occur in low amounts are 5,9,12-18:3 (<3.5%), 5,11-20:2 (<0.3%), 5,11,14-20:3 (<2.2%), and 5,11,14,17-20:4
(<0.3%) acids. In Torreya species, the major Δ5-olefinic acid is 5,11,14-20:3 (sciadonic) acid (between 6.7 and 11.2%). In contrast to Taxus species, the 5,9-18:2 and 5,9,12-18:3 acids are scarce in Torreya species: less than 0.1%. Also, the 9,12,15-18:3 acid content is significantly lower in Torreya than in Taxus. The prominence of taxoleic acid among Δ5-olefinic acids in the seed lipids is a unique characteristic of the genus Taxus that isolates it from all other Coniferophytes analyzed so far. However, this feature is not shared by other Taxaceae species,
such as Torreya, and with regard to their seed fatty acid compositions, the family Taxaceae appears particularly heterogeneous. Our observations
favor the hypothesis that in Gymnosperm seeds, there might exist two Δ5-desaturases, one specific for unsaturated acids with
a Δ9-ethylenic bond (active in Taxus but not in Torreya), and the other specific for unsaturated acids with a Δ11-ethylenic bond (active in Torreya but not in Taxus). Our data also highlight the importance of the elongase(s) in the metabolism of fatty acids in Gymnosperm seeds. 14-Methylhexadecanoic
acid, a habitual component of Pinaceae and Ginkgo biloba seed lipids, could not be detected in the Taxaceae studied here. 13C nuclear magnetic resonance spectroscopy of the oils from both genera has confirmed that Δ5-olefinic acids are apparently
excluded from the internal position of triacylglycerols, which is a characteristic common to all Gymnosperm species analyzed
so far, and consequently of great antiquity in their life history. 相似文献