胆固醇转运蛋白NPC1L1的研究进展

NPC1L1是近年来人们研究高脂血症的重点内容,该蛋白已被证实在胆固醇的肠道吸收和胆汁分泌中发挥了关键作用。NPC1L1调节体内胆固醇的生物合成,是维持生物体胆固醇动态平衡的重要因素,同时也是新型降脂药物依泽替米贝的作用靶点。     

Fat and cholesterol content and fatty acid composition of mares' colostrums and milk during five lactation months

In this study, the effect of the lactation stage on changes in the fat and cholesterol content and fatty acid composition of colostrum and milk of Wielkopolska mares' was investigated. Colostrum and milk samples from 10 lactating mares were collected at the beginning of lactation, on the 1st and 2nd day after foaling and then, starting from the first month of lactation, at 4 weeks' intervals up to the fifth month of lactation. Statistically significant differences were found between mares' colostrum and milk in the fat and cholesterol content as well as in the percentage rate of total fatty acids which occurred in significant quantities. Together with the lengthening of the lactation time, the content of fat and cholesterol in the mares' milk was observed to decrease. The authors also found a significant impact of the lactation period on changes in the ratio of polyenoic fatty acids from the n-6 to n-3 family. Bearing in mind the fat and cholesterol content and a more favourable (from the nutritional point of view) ratio of fatty acids from the family of n-6 to n-3, it is recommended to collect milk from mares in the 4th and 5th month of lactation.     

Alphaherpesvirus use and misuse of cellular actin and cholesterol

Two major structural elements of a cell are the cytoskeleton and the lipid membranes. Actin and cholesterol are key components of the cytoskeleton and membranes, respectively, and are involved in a plethora of different cellular processes. This review summarizes and discusses the interaction of alphaherpesviruses with actin and cholesterol during different stages of the replication cycle: virus entry, replication and assembly in the nucleus, and virus egress. Elucidating these interactions not only yields novel insights into the biology of these important pathogens, but may also shed new light on cell biological aspects of actin and cholesterol, and lead to novel avenues in the design of antiviral strategies.     

灵芝和菌糠降低鸡蛋胆固醇的试验研究

选取48周龄海兰褐商品蛋鸡120羽,随机分成3组,试验期为4周,对照组Ⅰ组喂基础日粮,试验Ⅱ组添加2.5g/kg灵芝,试验Ⅲ组添加2.5g/kg菌糠,在一致的背景下,探讨灵芝、菌糠对鸡蛋胆固醇的影响。结果表明:Ⅱ、Ⅲ组可降低蛋鸡血液甘油三酯(TG)、总胆固醇(TC)含量,增高血清高密度脂蛋白胆固醇(HDL-C)含量;3组之间料蛋比差异显著,Ⅱ、Ⅲ组料蛋比分别比对照组低6.4%(P<0.05)、11.0%(P<0.05)。Ⅱ、Ⅲ组平均产蛋率分别比对照组提高5.38%(P<0.05)和3.29%(P<0.05)。试验4周,Ⅱ、Ⅲ组鸡蛋胆固醇含量分别降低15.3%(P<0.05)和10.4%(P<0.05),且两组间差异显著(P<0.05),研究表明灵芝及菌糠均能提高蛋鸡生产性能,降低鸡蛋胆固醇含量。相比之下,灵芝是降低鸡蛋胆固醇较为理想的添加剂。     

Excess dietary cholesterol may have an adverse effect on growth performance of early post-larval Litopenaeus vannamei

One experiment was conducted to determine the nutritive value of cholesterol for post-larval shrimp, Litopenaeus vannamei. Four isoenergetic and isonitrogenous diets supplemented with four levels of cholesterol (D1, D2, D3 and D4 with 0, 0.5%, 1% and 2% cholesterol, respectively) were fed to triplicate groups of L. vannamei shrimp (mean initial wet weight 0.8 mg) for 27 days. After the trial, shrimp fed the D1 diet had the best growth performance (final body weights: FBW; weight gain: WG; specific growth rate: SGR), while there was no significant difference between diet treatments with respect to survival. The whole body crude protein level in the shrimp decreased with the increase in dietary cholesterol levels, while the whole body crude lipid level in shrimps in the D4 diet treatment was significantly higher (P < 0.05) than in other diet treatments. Dietary analysis indicated that the D1 diet contained 0.92% cholesterol prior to supplementation, which may have satisfied the dietary cholesterol requirement of post-larval L. vannamei; excess dietary cholesterol may thus lead to adverse effects on the growth performance of post-larval shrimp.     

An experimental study of hypercholesterolemia-induced disorder of Oddi's sphincter

AIM:To investigate the functional changes and histopathological basis of Oddi’s sphincter under hypercholesterolemia. METHODS:Twenty - four New Zealand rabbits were equally divided into be groups ran- domly. Experimental groups Ⅰ and Ⅱ fed with cholesterol - added forage for 4 and 8 weeks respectively before sacri- ficed. Images, functions and histopathological characteristics of Oddi’s sphincters of experimental groups were studied and compared with control group by cholangiography, catheter manometry, and quantitative analysis of nitric oxide synthase. RESULTS: The hasal pressures of proximal low - pressure segment of Oddi’s sphincter of hath experimen- tal groups Ⅰand Ⅱ (20.9±6.1 mmHg, 25 .6±9.1 mmHg, respectively) were higher than those of control group sig- nificantly (11.7±2.8 mmHg, P < 0.01, P < 0.01 ). The hasal pressures of distal high - pressure "valve" segment of both experimental pops (138 .4±45. 5 mmHg and 144. 5 ±40 .4 mmHg, respectively) were significantly higher than those of coned group (69.3±9.8 mmHg, P < 0.01 and P<0.01). The gallbladder volUmes of experimental group Ⅰ and Ⅱ (3.4±1.0 mL and 3.9±1.9 mL) were significantly larger than those of control group (2.0 ±1.9 mL, P < 0.05 and P < 0.01 ). Between groups there were no significant differences in nitric oxide synthase con- tents. Enlargement of the cell volume, wavy distortion of the cell membrane, loosening and disarrangement of myofila- ment, uneven in size and distribution of dense body, angulation of longitudinal axis between dense body and myofila- ment, swelling, congregated at one end of nucleoulus and disappearance of cristae of plasmosomes and concertration of chromosome at nucleolus margin were observed in experimental groups under electron-microscope. CONCLUSION: The diastole function of Oddi’s sphincter could be damaged by hyperecholesterolemia, inducing a functional disorder of Oddi’s sphincter with increased resistance in bile excretion. The result is retertion of bile in the gallbladder.     

家蚕丝素蛋白对大鼠胆固醇代射的影响

研究了经酸解后制得的家蚕丝素蛋白氨基酸组成以及对高血脂实验鼠血清和肝脏内胆固醇及转氨酶的活性变化的影响。结果表明：所得的家蚕丝素蛋白粉氨基酸组成丰富，其中甘氨酸、丙氨酸、丝氨酸和酪氨酸含量占全部氨基酸总量的95%；家蚕丝素蛋白能显著地降低血清胆固醇含量和谷草转氨酶及谷丙转氨酶活性，提高动物肝组织中的胆固醇浓度和谷丙转氨酶的活性。     

布氏乳杆菌PG-7去除胆固醇和抗氧化能力的研究

从糖蒜中筛选分离到的一株具有降胆固醇和抗氧化能力的产乳酸菌株PG-7,该菌对胆固醇的去除率为58.1%,对DPPH自由基和超氧自由基的清除率分别为91.7%和16.2%。克隆了PG-7的16S rD-NA序列,并以其同源性为基础构建了相关属种的系统发育树。结果表明,该菌16S rDNA序列全长1 638 bp,BLAST显示该菌株与乳杆菌属同源;PG-7菌株在进化关系上与布氏乳杆菌属(Lactobacillus buchneri)聚成一族。将其鉴定为布氏乳杆菌属,命名为:Lactobacillus buchneri PG-7。     

卵黄和低密度脂蛋白对冷冻保存绵羊精子胆固醇、磷脂含量的影响

为了探索绵羊冷冻精液受精率低的原因,在稀释液中用低密度脂蛋白代替卵黄冷冻绵羊精液,研究LDL对冷冻中精子脂类含量的影响。结果表明,以卵黄稀释液冷冻精液,精子胆固醇含量从鲜精的234．54nmol／10^9降低到163．76nmol／10^9精子,胆固醇与磷脂的比值（c／p）从0．54下降到0．36;以9g／100mL LDL代替卵黄,冷冻后胆固醇含量为243．73nmol／10^9精子,c／p值保持在0．50。研究得出在卵黄稀释液中冷冻绵羊精液,精子胆固醇流失,c／p值下降;以LDL代替卵黄,可有效保护精子胆固醇,避免流失,维持了精子c／p值。