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油脂是人体主要的三大营养素之一,合理膳食油脂对人体供能、提升免疫功能、维持神经和生理活性提供了保障。甘油三酯(TAG)作为食用油脂主要成分,在消化代谢后容易转化为储能脂肪,使机体负担较大。甘油二酯(DAG)是一种天然TAG替代脂,被证明具有多种营养功能。旨在为DAG作为新型健康油脂的应用提供理论基础,综述了DAG的代谢机制以及DAG主要的营养功能。DAG具有和TAG相似的理化性质,由于代谢途径与TAG的差异以及可以调控与脂肪氧化相关基因的表达,使DAG具有促进脂肪氧化、抑制体质量增加、降低内脏脂肪含量、改善血清胆固醇、调节血糖、降低血脂等多种功能。DAG的摄入可有效降低代谢综合征和心血管疾病发生的风险。 相似文献
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对乳酸发酵短杆菌生物合成赖氨酸的代谢途径及其代谢流量从理论上进行了分析,计算了乳糖发酵短杆菌合成赖氨酸的最大理论转化率。对代谢途径及其遗传调控进行了分析,通过NTG诱变育成了一株带有FP^S、AEG^r、Ma^r和Leu^-4种遗传标记的赖氨酸高产菌株,使赖氨酸的产量提高到54.6g/L,并分析了这些标记对代谢流量改变的影响。 相似文献
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Inclusion of fiber in the diet has been linked to the prevention of a range of illnesses and conditions. This review contains several ideas about the possible benefits of dietary fiber intake in patients with metabolic syndrome. The principal beneficial effects of a fiber-rich diet in these patients are: prevention of obesity, improved glucose levels, and control of the profile of blood lipids. We now also know that dietary fiber may favor the control of arterial blood pressure. Animal experiments have also shown the benefit of different types of fiber on these variables. Of particular relevance are the studies using obese Zucker rats, which present similar anomalies to those seen in patients with metabolic syndrome. There is therefore a growing interest in discovering new sources of natural fiber. Some of these different kinds of fiber may then be used as functional ingredients to obtain foods with properties that are beneficial to health. 相似文献
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醋酸高产菌株的选育及代谢控制发酵的研究 总被引:6,自引:1,他引:5
论述了利用紫外线诱变分离优良醋酸菌的方法及技术,同时通过实验对微生物的代谢机制、代谢控制醋酸菌发酵做了探讨。诱变菌株B9-1的产酸量可达7.55g/100mL,产酸能力稳定。是可进一步诱变提高产酸率并运用于生产的理想菌株。 相似文献
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《Journal of dairy science》2022,105(2):1768-1787
Newborn calves rely on lipids in colostrum for energy and immune function. The lipid concentration in colostrum, however, is highly variable, and little is known about its composition and maternal factors that influence its composition. The first objective was to measure plasma lipid composition of multiparous cows at 35 d before calving (BC; 35 ± 3 d; ± standard deviation) and 7 d BC (7 ± 2 d), their colostrum, and serum lipid composition of calves (24 h after birth) using multiple reaction monitoring profiling, which is an exploratory and highly sensitive lipidomic analysis method that screens lipids based on chemical functionality. Second, data were analyzed to determine if there were relationships between circulating lipids in the cow, colostrum lipids, and calf serum lipids. Third, relationships between markers of metabolic status of the cows and circulating and colostrum lipids were analyzed with correlation analysis. Blood was sampled and plasma prepared from multiparous cows (n = 16) at 35 and 7 d BC. Within 3 h of parturition, colostrum was collected from cows and fed to her calf. Calves received another feeding of colostrum within 12 h after birth and a serum sample was collected from each calf 24 h after the first feeding of colostrum. The metabolic status of cows was evaluated using insulin, glucose, and nonesterified fatty acid area under the curve in response to an intravenous glucose tolerance test performed at 3 wk BC. Lipids were extracted from plasma, colostrum, and calf serum and were analyzed using multiple reaction monitoring profiling. Concentration of lipids were calculated using spiked in standards and expressed as percent of lipids identified. Data were uploaded into MetaboAnalyst 5.0 for multivariate and univariate analysis. Principal component analysis indicated that circulating lipids in the cow and calf were distinct from lipids in colostrum. Phosphatidylglycerol (PG) concentration was greater in colostrum and calf serum than in cow plasma, with 23 of the 24 PG found in colostrum also found in calf serum. In response to intravenous glucose tolerance test in late gestation, nonesterified fatty acid area under the curve was positively related to total triacylglycerols lipids in 7 d BC plasma (r = 0.63) but negatively related to total membrane lipids in colostrum (r = ?0.55). Thus, the metabolic status of the dam influences circulating lipids and colostrum lipid content. Moreover, the circulating lipidome of the cow and calf are similar to one another and distinct from the colostrum lipidome, except for PG, where it appears that colostrum serves as the source for PG in the calf's circulation. 相似文献
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该研究利用代谢组学的技术手段对两个通过群体选育获得的云南普洱茶优良品种进行分析,结果表明:品种1(桃形叶)共检测和定量了798种代谢物,品种3(云瑰)共检测和定量了802种代谢物,二者之间有202种显著变化的代谢物(SCMs),品种1(桃形叶)较品种3(云瑰)有108种SCMs的丰度显著降低,而有94种显著增加。这些SCMs按照数量的多少通常可以分为黄酮、酚酸类、脂质、氨基酸及其衍生物、木脂素和香豆素、有机酸、生物碱、核苷酸及其衍生物、鞣质和其他类。且差异代谢物在49条KEGG通路中富集,大多数已经鉴定的差异代谢物存在于苯丙烷类生物合成、苯丙氨酸代谢、类黄酮的生物合成(包括黄酮及黄酮醇的生物合成),及氨基酸的生物合成等代谢途径中。这些显著差异代谢物可以用于为品种1(桃形叶)与品种3(云瑰)的监控茶叶适制性和品质控制提供理论依据和科学指导。 相似文献
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The objective of this work was to estimate the genetic variation of free fatty acids (FFA), glucose, growth hormone (GH), and insulin in juvenile male dairy calves and to assess the relationships, if present, with the fertility of their female offspring. This study used data from 1,498 (269.5 d of age ± 11.1) male calves from a multiple ovulation and embryo transfer breeding scheme (data collected from 1997 to 2002). Calves were Danish Holstein (n = 1,047), Danish Jersey (n = 200), and Red Dane (n = 251), and were sampled following an overnight fast at approximately 9 mo of age. Plasma samples were assayed for basal FFA, glucose, GH, and insulin. Estimated breeding values of female fertility (high values indicating better fertility), based on progeny-test results for approximately 100 daughters per sire, were available for a subset (n = 810) of the male calves as adult sires. Data from Danish Holstein alone or Danish Holstein, Red Dane, and Danish Jersey combined (all breeds) were analyzed for each trait. In both data sets, the estimates of heritabilities of glucose (0.27 ± 0.06), FFA (0.11 ± 0.05), and insulin (0.21 ± 0.06) were moderate, and that of GH (0.09 ± 0.05) was low. Correlations of estimated breeding values for fertility traits with glucose and FFA breeding values were negative, indicating that male calves with high glucose or FFA had female offspring with reduced fertility. Selection for bull calves with lower concentrations of glucose and FFA following an overnight fast could result in female offspring with genetically better fertility. Glucose and FFA may therefore be of interest to enhance selection for improved female fertility, as a measurement in young bulls. 相似文献
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对基于KEGG在线数据库、Uniprot-MetaCyc数据库,以及同源比对3种构建基因组规模代谢网络模型的方法进行了自动化研究。同时提出了基于反应式字符频度直方图的马氏距离比对算法,并应用于模型整合和模型核心反应的识别。上述自动化方法的研究均在树干毕赤酵母基因组规模代谢网络重构过程中得到运用实施,对于提高模型构建效率意义重大。 相似文献
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双乙酰是啤酒生产过程中由酵母在合成氨基酸的途径中产生的重要风味物质,其含量是衡量啤酒成熟的重要标志。本文简要综述了啤酒生产中双乙酰的形成机制和代谢调控研究进展。 相似文献
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In vivo and in vitro models of the human colonic flora. 总被引:5,自引:0,他引:5
The study of colonic flora composition and metabolism presents considerable methodological problems. Attempts to circumvent these problems have led to the development of numerous in vitro and in vivo models to simulate the human colon and its microbial population. In terms of in vivo models, conventional laboratory animals have many limitations. Data of greater relevance to man can be obtained by using germ-free rodents associated with human colonic bacteria. The applications of such animals to studies of toxicity of chemicals and gastrointestinal infections are discussed. The advantages and disadvantages of the various in vitro systems for studying gut microflora and its metabolic activity (from simple static cultures to the more sophisticated continuous and semicontinuous flow models) are reviewed. The apparatus involved is described together with practical information on media, running conditions, and sampling. The bacteriological and metabolic criteria for establishing the similarity of the models to the in situ colonic flora are also discussed. The final sections of the review are devoted to the major applications (current and future) of the models, including fermentation studies on dietary fiber, metabolism of nutrients and foreign compounds (including carcinogens) in food, and the investigation of colonization resistance. 相似文献