Effect of various dietary proteins on the processes of lipid transport in the blood serum

The influence of isocaloric semi-synthetic rations with varying protein components (casein, wheat gluten, isolates of cotton, soybean and rice proteins) on lipid transport processes in the blood serum was studied in experiments on made August rats. It has been shown that the alimentary proteins studied affect blood serum lipids and lipoproteins by altering lypolysis activity in the serum, by modifying the hepatic production of high-density lipoproteins and their free cholesterol, by disturbance of low-density lipoprotein degradation. The rest mechanisms regulating lipid transport in the blood serum are changed insignificantly.     

Effect of dietary fats and carbohydrates on protein restoration in the myocardium

A study was made of the effect of high-fatty and high-carbohydrate diets on the rate of the renewal of individual rat myocardial proteins, particularly on the half-life and the constant of degradation of proteins of sarcoplasm, myosin and actin. Unlike the control diet, the high-carbohydrate diet increased the rate of myosin renewal by 25%, while the fatty diet retarded 20% the rate of the renewal of the main contractile myocardial protein. Similar changes were also found for proteins of sarcoplasma: with the high-carbohydrate diet the rate of the renewal increased 10%, whereas with the high-fatty one it diminished 47%. The rate of actin renewal dropped 11% with the high-carbohydrate diet and 30% with the high-fatty diet. Unbalance in carbohydrate and fatty supply of the body produces appreciable changes in the rate of the renewal of individual proteins of the rat myocardium.     

Effect of enterococcin A 2000 on biological and synthetic phospholipid membranes

Lactic acid bacterium isolated from Bulgarian cheese and identified as Enterococcus faecium produces a small hydrophobic peptide substance (enterococcin A 2000) with broad spectrum of antimicrobial activity. The wide range of enterococcin antibacterial activity of this compound against Gram-positive, as well as against some Gram-negative bacteria, suggests a single mechanism of action. The mode of action of enterococcin A 2000 was studied in intact liver mitochondria and synthetic phospholipid liposomes used as model systems. Enterococcin A 2000 stimulated the ATPase activity in intact mitochondria. The kinetic curve of ATP hydrolysis differed from that obtained in presence of dinitrophenol (DNP) and showed a character similar to the ATP hydrolysis in the presence of classic ionophores. Enterococcin A 2000, when bound to synthetic phospholipid liposomes, permeabilized liposomes liberating the marker carboxyfluorescein (CF).     

Effect of alimentary alpha-tocopherol deficiency on the fatty acid composition of phospholipids in the subcellular membranes of the liver cells and high density lipoproteins in the blood plasma

In experiments on rats a positive correlation was demonstrated between the changes in the fatty-acid composition of hepatocytic intracellular membrane phospholipids and blood plasma high density lipoproteins. The data obtained evidence the existence in the blood of several mechanisms of alpha-tocopherol deficiency action on hepatocytic phospholipids and blood plasma protein-lipid complexes.     

Effect of various dietary fats and proteins on serum cholesterol level in rats

A 60 day experiment on growing rats was performed to evaluate the effect of two protein sources (casein and soybean protein isolate) and four fats (olive oil, OO; evening primrose oil, EO; linseed oil, LO; and butter, B) on plasma lipoprotein fractions: total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol (LDL‐C) and triacylglycerol (TAG) levels. The different protein and fat sources had no influence on body weight gain of rats. Fats had no significant effect on TC and LDL‐C. Significant differences were found only in HDL‐C. OO gave the lowest (43.3 mg dl^?1) and EO the highest (54.4 mg dl^?1) value. Proteins had a significant influence on all lipids analysed. Soybean protein caused higher TC (78.5 vs 67.9 mg dl^?1), HDL‐C and TAG levels but significantly lowered LDL‐C in the plasma of rats. These results suggest that protein has a stronger effect on cholesterol level than fat. © 2002 Society of Chemical Industry     

磷脂结构、膳食来源及营养学研究进展北大核心CSCD

磷脂是一类复合极性脂质,拥有独特的生理活性,对维持机体正常生命活动以及营养健康起着至关重要的作用。为了对膳食磷脂的营养学研究以及相关代谢疾病的预防提供参考,对磷脂的结构组成与生理活性、膳食来源及其营养学特性进行了综述。根据分子结构,磷脂可以分为不同的类型,也具有不同的生理功能以及营养特性;此外,磷脂的膳食来源丰富,但不同膳食来源的磷脂组成及含量存在差异。不同类型磷脂在改善记忆、提高免疫力以及预防心脑血管等代谢性疾病方面都发挥着很大的作用。     

Effect of vitamin A deficiency on ATPase activity and the transport functions of erythrocyte membranes

Influence of vitamin A deficiency on ATPase activity in erythrocytes was studied experimentally. It was shown that activity of Mg2+, Na+, K+-ATPase increased, while that of Na+, K+-ATPase decreased under such conditions. The assay of K+ and Na+ in erythrocytes and plasma revealed diminished K+ content in erythrocytes and its elevated level in plasma, Na+ concentration in erythrocytes rose. The author considers that disorders of protein biosynthesis (at the level of translation) in hypovitaminosis A are responsible for the results obtained.     

Molecular property-affinity relationship of the interaction between dietary polyphenols and bovine milk proteins

The relationship between the molecular properties of dietary polyphenols and their affinities for bovine milk proteins (BMP) was investigated. The affinities of polyphenols for BMP were determined by means of fluorescence titration. The affinities of polyphenols for BMP increased with increasing partition coefficient and decreased with increasing hydrogen bond acceptor number of the polyphenol. From this point, the hydrophobic force played an important role in the binding interaction between polyphenols. It was found that the topological polar surface area value decreases with increasing binding constant of the polyphenol for BMP, which illustrates that the glycosylation of hydroxyl groups in polyphenols weakens their binding affinity for BMP. A strong correlation between Mulliken electronegativity and binding affinity was found (R = 0.64626), and Mulliken electronegativity values were found to increase with increasing binding constant of polyphenols for BMP. This illustrates that electrostatic interactions play a key role in binding dietary polyphenols to BMP.     

膳食油脂与非酒精性脂肪肝病形成相关研究进展

市场中的膳食油脂产品琳琅满目,消费者在选择食用油的过程中通常会考虑其对健康的影响,尤其是广泛流行的营养代谢性疾病非酒精性脂肪肝病（NAFLD）。我国NAFLD的患病率持续增长,给个人和社会造成巨大的压力。大量的研究表明,膳食油脂与NAFLD的形成关系密切,合理的膳食用油能有效预防NAFLD。通过对油脂脂肪酸链长、饱和度及双键位置、奇偶性与NAFLD形成的相关研究进行梳理,结合饮食模式综述了膳食油脂与NAFLD形成相关研究进展,以期为学术探索和日常膳食油脂提供依据。     

Effect of a dietary regimen with separated administration of protein on liver in the rat]

Rats received a protein-deficient standard diet and, separately at different hours of the day, protein (casein). The control group was given the standard diet added with casein. The livers of the rats were examined for histological and ultrastructural changes. The smallest changes were observed in animals which had received protein at eight o'clock. The control animals and the animals which had received protein at thirteen and nineteen o'clock, respectively, showed slight fatty infiltration of the liver.     

Effect of dietary fat and lactation status on insulin binding to bovine milk fat globule membranes

Lactating cows were used to examine the relationship between lactation status and insulin binding to milk fat globule membranes. Variables evaluated were daily milk yield, stage of lactation, breed, age, lactation number, daily milk fat and protein yields, milk fat and protein percentages, breeding status, body weight, body weight.75, and mammary health. Milk yield was correlated with insulin binding and accounted for 20% of the binding variability. No other variables were related to insulin binding. Insulin binding to milk fat globule membranes increased with supplemental dietary fat up to 4% added fat in the diet dry matter. Milk fat globule membranes may provide a useful model for assessing insulin receptor regulation in the mammary gland. Sources of variation in insulin binding to mammary membranes remain to be identified.     

Effect of soybean trypsin inhibitor and chicken ovomucoid on the immunogenic and sensitizing properties of various dietary proteins

Adult male guinea pigs were sensitized by intragastric administration of bovine serum albumin (BSA) and chick ovalbumin (OA) and their mixtures with soybean Kunitz trypsin inhibitor (SBTI) and chick ovomucoid (OM). Sensitization of the animals was evaluated by the anaphylactic shock reaction and also by the levels of serum specific IgG antibodies against BSA and OA as measured in the solid phase radioimmunoassay. The experiment revealed pronounced desensitizing properties of SBTI combined both with OA and BSA. OM produced no effect on the animal sensitization caused by OA and enhanced the BSA-induced sensitization. The results obtained demonstrate the necessity of differential approach to the evaluation of the action of varying trypsin inhibitors on food sensitization.     

Effect of the total replacement of fats in the diet with a phospholipid concentrate on oxidative phosphorylation in liver mitochondria and the lipid composition of the plasma and liver in rats

Experimental rats were given rations with 100% substitution of fats for phospholipid concentrate, during 1 and 3 months. It was found that such rations produced hypolipidemic and hypocholesterolemic effects, that were most pronounced at the end of the experiment. A control ration with sunflower oil containing high levels of unsaturated fatty acids induced accumulation of lipid peroxides in the hepatic tissue and blood plasma of the animals fed with the ration during 3 months. The ration containing the phospholipid concentrate did not produce such an effect. The data obtained have evidenced a positive influence of the phospholipid concentrate on the lipid metabolism parameters studied.     

Effect of cold storage and freezing of bovine and porcine liver on activity and subcellular distribution of mitochondrial enzymes

The subcellular distribution of the mitochondrial enzymes lipoamide dehydrogenase (LIPDH), citrate synthase (CS), and beta-hydroxyacyl-CoA-dehydrogenase (HADH) in bovine and porcine liver tissue was studied by measuring the enzyme activities in a phosphate buffer extract of tissue (total activity) and in liver press-juice (cell plasma). In slaughter-fresh liver most of the activity was located in the mitochondria. During storage of liver under refrigeration (+2 degrees C) for several days a large decrease in total LIPDH activity and a lesser decrease in HADH activity, but no change in CS activity were observed. There was no or only little release of the three enzymes into the cell plasma during storage; this indicates that storage of liver at +2 degrees C was not accompanied by a marked damage of mitochondria. Freezing (-20 degrees C) and thawing of bovine and porcine liver caused some losses of the total activity of HADH and particularly of LIPDH but not changes in CS activity. There was a considerable increase in the activities of LIPDH, CS, and HADH in the press juice after freezing and thawing of liver tissue. Apparently freezing of liver results in damage to the mitochondria and, therefore, in a partial release of the three enzymes from the inner membrane of the mitochondrion into the cell plasma. By storage of liver under refrigeration the mitochondria became more sensitive to freezing and thawing. Prolonged frozen-storage of liver resulted in an increased release of LIPDH, CS, and HADH into the cell plasma.     

日粮亮氨酸水平与宫内发育迟缓对断奶仔猪肝脏抗氧化功能的影响

研究日粮亮氨酸水平与宫内发育迟缓（IUGR）对断奶仔猪肝脏抗氧化功能的影响。挑选16头正常初生重（NBW）仔猪和16头IUGR仔猪,公母各半。仔猪于14日龄断奶,采用2×2因子设计,一半NBW与IUGR断奶仔猪饲喂基础日粮,剩余断奶仔猪饲喂添加0.35%亮氨酸的实验日粮,即4个处理组,每个处理组8个重复,每个重复1头仔猪。实验期为21 d。结果表明:与NBW断奶仔猪相比,IUGR断奶仔猪肝脏总超氧化物歧化酶（T-SOD）活力显著降低,丙二醛（MDA）含量显著升高（p<0.05）。IUGR断奶仔猪肝脏线粒体锰超氧化物歧化酶（Mn-SOD）活力、谷胱甘肽过氧化物酶（GSH-Px）活力、还原型谷胱甘肽（GSH）含量较NBW断奶仔猪均显著降低（p<0.05）。另外,IUGR显著降低断奶仔猪肝脏核转录因子2（Nrf2）、超氧化物歧化酶1（SOD1）、超氧化物歧化酶2（SOD2）、谷胱甘肽过氧化物酶1（GPx1）mRNA表达量（p<0.05）。日粮添加0.35%亮氨酸可显著降低断奶仔猪肝脏MDA含量,显著提高SOD2 mRNA表达量（p<0.05）。高亮氨酸水平日粮可显著缓解IUGR介导断奶仔猪线粒体GSH含量降低与肝脏SOD2和GPx1mRNA表达下调（p<0.05）。因此,日粮添加0.35%亮氨酸,可降低断奶仔猪肝脏脂质过氧化程度,一定程度缓解了IUGR对断奶仔猪肝脏抗氧化功能的不良影响。