胆固醇氧化酶发酵研究

对从土壤中筛选到的菌株ＤＧＣ－００７进行ＵＶ诱变,选育到菌株ＤＧＣ－０４８．对影响突变株产酶的条件进行了优化,初步确定了ＤＧＣ－０４８合适的产酶摇瓶培养基组成．在发酵温度为３０℃,培养基起始ｐＨ７．５～８．０的条件下,接种量１０％,发酵４８ｈ,产酶可达３５０μｍｏｌ／（ｍｉｎ·Ｌ）     

光化学合成维生素D

本文报道了维生素D的发现以及它们的光化学合成与进展。中国科学院理化技术研究所开发了一条从胆固醇合成 7 DHC的新路线,提出了一条光化学合成维生素D3 的创新技术路线,并已经转让实施。同时还提出一条光化学合成维生素D2 的创新技术路线。     

一株具降胆固醇功能的海洋源植物乳杆菌的筛选及其益生性能分析

本文采用邻苯二甲醛法从喙鲸内脏中筛选分离出一株高效降胆固醇能力的乳酸菌HJ-S2,考察并研究了乳酸菌HJ-S2的体外益生性能。通过耐酸、耐胆盐测定菌株的益生作用,研究了其对致病菌的抑菌作用及对人结肠癌细胞HT-29的粘附能力,利用形态学、API50CH和16S rDNA对菌株进行鉴定。乳酸菌HJ-S2体外降胆固醇能力达到48.82%,在p H值3的酸性环境中培养3h耐受率达到82.73%,在含0.3%的胆盐环境中培养3 h耐受率达80.62%。菌株代谢物对致病菌大肠杆菌、金黄色葡萄球菌和沙门氏菌均有一定的抑菌作用,且菌株对人结肠癌细胞HT-29很强的粘附能力,粘附细菌数为132.52,经鉴定为植物乳杆菌Lactobacillus plantarum,并命名为HJ-S2(CGMCCNO:17720)。筛选得到的植物乳杆菌HJ-S2体外具有高效降胆固醇能力,可进一步开发为功能性微生态制剂。     

Diversity of Lipid Function in Atherogenesis: A Focus on Endothelial Mechanobiology

Atherosclerosis is one of the most important problems in modern medicine. Its high prevalence and social significance determine the need for a better understanding of the mechanisms of the disease’s development and progression. Lipid metabolism and its disorders are one of the key links in the pathogenesis of atherosclerosis. Lipids are involved in many processes, including those related to the mechanoreception of endothelial cells. The multifaceted role of lipids in endothelial mechanobiology and mechanisms of atherogenesis are discussed in this review. Endothelium is involved in ensuring adequate vascular hemodynamics, and changes in blood flow characteristics are detected by endothelial cells and affect their structure and function.     

Nutritional effects of mustard seed protein detoxified with aqueous isopropanol in young rats

The effect of removing anti‐nutritional factors from n‐hexane‐extracted mustard meal using 80% isopropanol (to reduce thioglucosides, phenolics, etc.) on growth, food efficiency ratio, serum and liver lipid profiles and protein content of young rats was examined. For this n‐hexane‐extracted mustard meal was extracted with 80% isopropanol giving a fraction with 68% protein and low residual thioglucoside (0.5%) as well as phenolic (0.3%) content. This isopropanol‐extracted mustard seed protein fraction reduced the growth of young rats slightly when compared with casein. The food efficiency ratio between rats fed isopropanol‐extracted mustard seed protein or casein did not differ, nor did the protein composition affect serum total cholesterol, triglyceride, HDL‐cholesterol, LDL‐cholesterol, VLDL‐cholesterol and LDL‐C/HDL‐C ratio. However, rats fed isopropanol‐extracted mustard seed protein showed a significantly lower (p<0.05) liver cholesterol concentration than rats fed casein. Liver triglyceride and phospholipid concentrations did not differ between rats fed the two proteins, nor was serum protein affected. This study indicates that extraction of hexane‐extracted mustard meal with 80% isopropanol reduced a number of anti‐nutritional factors like thioglucoside and phenolics. Furthermore the nutritional quality of mustard seed protein fraction is comparable to casein in respect to growth, food efficiency ratio, serum lipid and protein concentrations and organ weights.     

Dietary fat in the prevention of cardiovascular disease — a review

In developed countries atherosclerotic cardiovascular disease is the reason for about 50% of all deaths. With growing prosperity coronary heart disease (CHD) is becoming the major cause of premature death. Most complications of atherosclerosis occur unexpectedly and more than 50% of the patients developing a myocardial infarction do not survive more than one year. Because of the severe morbidity and high mortality primary prevention is likely to be the only solution. Epidemiological studies show a strong, positive relationship between plasma cholesterol concentrations and the incidence of CHD. People who immigrate from low‐risk to high‐risk areas usually acquire similar plasma cholesterol levels as the native population and a similar CHD risk. This demonstrates that environmental rather than genetic factors lead to the differences in cardiovascular risk and supports the notion that nutrition and lifestyle play a major role. The association between dietary intake of fat and cholesterol and the extent of atherosclerosis and CHD has been recognized in previous studies. The amount of saturated fat in the diet correlates stronger with the incidence of CHD than with total fat intake. The consumption of unsaturated fatty acids, however, appears to be beneficial, since it is inversely correlated with the plasma cholesterol concentration and risk of myocardial infarction. Lately additional nutritional factors like trans fatty acids with a negative influence on risk as well as positive factors like linolenic acid have attracted much attention. In conclusion, as a challenge to public health, preventive medicine needs to focus on changes in dietary habits with priority, particularly fat modification. A nutrition low in total fat primarily avoiding saturated and trans fatty acids, but rich in fruit and vegetables should be recommended.     

Barley β-glucan is effective as a hypocholesterolaemic ingredient in foods

Barley contains high levels of soluble dietary fibre, including mixed linked 1→3, 1→4β-D -glucans (β-glucan). An extract of β-glucan from waxy, hulless barley containing 56% total dietary fibre (TDF) was incorporated into flour tortillas, cornstarch pudding and apple granola bars to provide 2 g soluble fibre as β-glucan per serving. The foods were tested for objective functional properties. Flour tortillas with β-glucan were incorporated into rat diets and compared to diets containing an equivalent amount of cellulose, to test the fibre effect on growth and lipid metabolism parameters. Rats fed β-glucan tortillas had lower feed consumption and body weight (P<0·05) compared to those fed the cellulose tortillas, although feed/gain ratios were not different (P>0·05). Plasma LDL-cholesterol of rats fed β-glucan was lower (P<0·05) than cellulose-fed controls, although total cholesterol and triglycerides did not differ (P>0·05). Rats fed β-glucan tortillas had higher (P<0·05) faecal fat excretion, suggesting impairment of intestinal fat absorption. Liver composition data showed lower (P<0·05) levels of total lipid and cholesterol in β-glucan-fed rats. The results suggest that the barley β-glucan concentrate has potential as a food ingredient to provide supplemental soluble fibre which may be beneficial in reducing plasma LDL-cholesterol in humans. © 1998 SCI.     

Impaired Retromer Function in Niemann-Pick Type C Disease Is Dependent on Intracellular Cholesterol Accumulation

Niemann-Pick type C disease (NPC) is a rare inherited neurodegenerative disorder characterized by an accumulation of intracellular cholesterol within late endosomes and lysosomes due to NPC1 or NPC2 dysfunction. In this work, we tested the hypothesis that retromer impairment may be involved in the pathogenesis of NPC and may contribute to increased amyloidogenic processing of APP and enhanced BACE1-mediated proteolysis observed in NPC disease. Using NPC1-null cells, primary mouse NPC1-deficient neurons and NPC1-deficient mice (BALB/cNctr-Npc1m1N), we show that retromer function is impaired in NPC. This is manifested by altered transport of the retromer core components Vps26, Vps35 and/or retromer receptor sorLA and by retromer accumulation in neuronal processes, such as within axonal swellings. Changes in retromer distribution in NPC1 mouse brains were observed already at the presymptomatic stage (at 4-weeks of age), indicating that the retromer defect occurs early in the course of NPC disease and may contribute to downstream pathological processes. Furthermore, we show that cholesterol depletion in NPC1-null cells and in NPC1 mouse brains reverts retromer dysfunction, suggesting that retromer impairment in NPC is mechanistically dependent on cholesterol accumulation. Thus, we characterized retromer dysfunction in NPC and propose that the rescue of retromer impairment may represent a novel therapeutic approach against NPC.