细菌胞外多糖生物合成多水平调控

在依赖C_(55)-Lipid-p糖基载体脂的细菌胞外多糖生物合成中,糖基底物、糖基-核苷酸和C_(55)-Lipid-p糖基载体脂是糖基的三级供体。细菌通过糖基三级供体多水平控制胞外多糖生物合成。了解胞外多糖生物合成多水平调控对微生物胞外多糖发酵生产有重要的指导意义。例如,筛选底物吸收能力强或C_(55)-Lipid-p含量高的菌株,或通过控制发酵条件维持C_(55)-Lipid-p糖基载体脂高效的运载活性皆能提高胞外多糖的发酵水平。底物的吸收和代谢流向控制     

马尾松花粉醇提物降脂作用与预防肥胖的实验研究

本实验通过观察马尾松花粉醇提物对小鼠脂质代谢的影响来探讨其抑制肥胖的初步机制.实验采用随机分组对照方法,对不同组的小鼠进行不同的干预处理.实验结果显示与高脂组(FC)组相比3个醇提物组在终体重、体重净增加和体重增加率方面都有明显降低(P＜0.01);体脂含量也有不同程度降低但未出现显著性差异;血脂中总胆固醇(TC)水平有不同程度的降低,并且甘油三酯(TG)都有明显降低(P＜0.01),高密度脂蛋白胆固醇(HDLC)水平都有显著性升高(P＜0.01);瘦素(LEP)和脂联素(ADP)水平都有不同程度升高;肝脏和脂肪组织中的肉碱棕榈酰转移酶(CPT-I)酶含量水平都得到显著升高(P＜0.01).上述结果证明马尾松花粉醇提物可以明显控制小鼠的体重增长以及改善体内脂质代谢水平,证明松花粉醇提物在抑制肥胖方面具有重要作用.     

高脂饮食及运动对2型糖尿病大鼠脂联素、瘦素及血糖水平的影响

目的：观察高脂饮食及运动对糖尿病大鼠脂联素、瘦素及血糖水平的影响。方法：选取SD清洁大鼠80只,雌雄各半,随机分为5组（n=16）：空白对照组（A）,普通饮食组（B）,高脂饮食组（C）,普通饮食干预组（普通饮食+运动干预,D）,高脂饮食干预组（高脂饮食+运动干预,E）;除空白组外,其余四组均给予高糖高脂饲料喂养6周后,腹腔链脲佐菌素（30 mg/kg）制备2型糖尿病模型（T2DM）;大鼠建模后,空白组、普通饮食组及普通饮食干预组给予常规饲料,高脂组及高脂饮食干预组大鼠给予高脂饲料,普通饮食干预组及高脂饮食干预组给予运动干预,采用滚筒训练器进行运动,运动频率为每天1次,每周6次,持续6周。6周后测量大鼠脂联素、瘦素、血糖及相关生化指标。结果：除空白组外,其余四组大鼠实验后脂联素水平明显降低（P<0.05）、瘦素、血糖、糖化血红蛋白、甘油三酯明显升高（P<0.05）;高脂饮食组大鼠瘦素、血糖、糖化血红蛋白、甘油三酯水平明显高于高脂饮食干预组（P<0.01）;高脂饮食干预组大鼠瘦素、血糖、糖化血红蛋白、甘油三酯水平高于普通饮食组（P<0.05）;普通饮食组瘦素、血糖、糖化血红蛋白、甘油三酯水平高于普通饮食干预组（P<0.05）;T2DM大鼠模型各组瘦素、血糖、糖化血红蛋白、甘油三酯水平均明显高于对照组（P<0.01）。高脂饮食组大鼠脂联素水平明显低于高脂饮食干预组（P<0.01）;高脂饮食干预组脂联素水平低于普通饮食组（P<0.05）;普通饮食组脂联素水平低于普通饮食干预组（P<0.05）;T2DM大鼠模型各组脂联素水平均明显低于对照组（P<0.01）。脂联素与血糖,瘦素与血糖均有相关性（R<-0.06/R>0.06,P<0.05）。结论：严格的饮食控制及运动有助于控制2型糖尿病大鼠血糖水平的稳定,其可能与控制调节大鼠体内瘦素及脂联素水平有关。     

肠道修复：一种利用益生菌减少重金属积累的新思路

近年来受到重金属工业废水的排放及人类日常活动的影响,我国大面积土壤中重金属含量急剧增高。不同重金属可能通过食物链进入人体,给人类健康带来隐患。因此,减少重金属在动物体肠道中的积累是降低重金属危害的一个重要课题。研究显示,一些益生菌能够在体内外环境中有效地结合重金属,但人们对益生菌结合重金属的能力,及其对重金属的肠道修复机理了解较少。本文针对目前镉、铅、铬等重金属对环境与动物体健康造成严重危害的现状,分析了各类重金属的污染来源,概括了益生菌在环境与动物体肠道中对各种重金属的修复情况及作用机理,重点考察了益生菌在动物体肠道环境中与重金属相互作用的机理研究,同时对未来利用益生菌制剂直接减少人体肠道内重金属积累进行了展望。     

介绍一套从水—空气界面的脂单层制备水相中平面脂双层的新装置

本文介绍了一种从水—空气界面的脂单层形成平面双分子脂膜的新装置。它可以控制膜两侧溶液的不同成分;脂双层两边的脂单层具有不同成分;还可使脂双层膜中少带或不带碳氢溶剂,因而其电容性质与生物膜更为接近。我们用它测定了不对称双分子层脂膜的电特性,进行了膜上离子通道性质及脂质体与BLM的融合等的研究。     

不同负荷的运动干预对糖尿病大鼠血清脂联素的影响

目的:观察不同运动强度下糖尿病大鼠血清脂联素的影响,并初步探讨血清脂联素与血清胰岛素的关系。方法:将SD大鼠分为5组:正常对照组(CON组)、糖尿病非运动组(DM0组)、糖尿病小强度运动组(DM1组)、糖尿病中等强度运动组(DM2组)和糖尿病大强度运动组(DM3组),每组6只。采用高糖高脂饮食饲养4周后一次性腹腔注射链脲佐菌素(Streptozotocin)制备糖尿病大鼠模型。6周跑台运动前后检测大鼠尾静脉空腹血清胰岛素(FINS)、血清脂联素(ADIPO)水平。结果 :小强度FINS和APIDO无明显变化,中强度FINS和APIDO明显升高,大强度运动组FINS和APIDO明显升高。脂联素与胰岛素水平相关性分析:DM1组无明显相关性,DM2组和DM3组有正相关性。结论:不同运动强度下糖尿病大鼠血清脂联素水平不一致,而且胰岛素水平与脂联素水平存在一定的变化关系。     

饲料糖和脂水平对团头鲂生长性能及血浆代谢物的影响

实验以初重(6.20±0.01) g的团头鲂(Megalobrama amblycephala)幼鱼为研究对象, 分别投喂高糖低脂(HCLL, 45%糖和2%脂)、中糖中脂(MCML, 30%糖和8%脂)和低糖高脂(LCHL, 15%糖和14%脂)的3种等氮饲料56d, 以探究饲料不同糖和脂水平对团头鲂生长性能、鱼体生化组成、营养沉积及血浆代谢物的影响。实验结果显示, 饲料糖和脂水平对团头鲂摄食率无显著性影响。随饲料糖水平降低和脂水平升高, 团头鲂幼鱼特定生长率和饲料效率提高。高糖低脂饲料未造成肝脏糖原或甘油三酯含量的显著沉积, 且各饲料组间肝体比、脏体比及肥满度均无显著性差异。饲料糖和脂水平对团头鲂鱼体生化组成无显著性影响, 但随饲料糖水平降低和脂水平增加, 团头鲂蛋白沉积率升高, 脂肪沉积率降低。另外, 血浆葡萄糖、甘油三酯、游离脂肪酸和胆固醇含量各组间均无显著性差异。低糖高脂组血浆低密度脂蛋白胆固醇显著升高, 表明肝脏将脂质转运至外周组织以维持肝脏脂稳态。研究结果表明, 团头鲂对饲料脂利用优于糖类, 且具有较好地应答饲料糖和脂水平的代谢机制, 研究结果可为团头鲂的饲料配方设计提供支撑。     

突触的结构及其传递功能

一、突触的概述 1.突触的定义人和动物体的许多器官、组织的活动是通过激素传递和神经冲动的传导来实现的。前者是由某些特殊细胞释放的激素来进行调节,后者由神经系统来进行控制,其速度和选择性较前者更为优越,是调节控制体内器官、组织活动的最复杂而又最灵敏的系统。     

锌-α2-糖蛋白与体脂

锌-α2-糖蛋白(zincα2 glycoprotein,ZAG)是一种新的脂肪因子,它能促进脂肪分解代谢。ZAG与体脂存在一定的联系:恶病质患者体脂减少,血清ZAG浓度显著升高;肥胖患者体脂增多,血清ZAG水平比正常人低;在一些疾病状态下ZAG表达上调,引起体脂下降。本文就不同状态下体脂与ZAG表达之间的关系进行综述。     

不同亚型脂联素与非酒精性脂肪性肝病的关系

目的:探究总脂联素(total adiponectin,total APN)和高分子量脂联素(high-molecular-weight adiponectin,HMW APN)与非酒精性脂肪性肝病(Nonalcoholic Fatty Liver Disease,NAFLD)的关系。方法:连续纳入50名男性健康男性及50名非酒精性脂肪性肝病男性患者,收集患者临床资料及其他临床生化数据,通过ELISA法检测总脂联素、支链氨基酸及可溶性晚期糖基化终末产物含量,Western blot法测定高分子量、中分子量和低分子量脂联素水平,进一步分析其相关性。结果:与对照组的健康受试者相比,NAFLD患者的总脂联素和三种不同形式的脂联素水平均显著降低。在NAFLD患者中,总脂联素与身高(R=-0.270, P=0.032)和羧甲基赖氨酸(R=-0.259, P=0.040)显著负相关;高分子量脂联素与空腹血糖(R=0.350, P=0.016)显著正相关,与丙氨酸氨基转移酶(R=-0.321, P=0.029)和天门冬氨酸氨基转移酶(R=-0.295, P=0.045)显著负相关。结论:总脂联素和三种不同形式的脂联素水平均与NAFLD呈显著负相关。     

Factors influencing the levels of fatty acid synthase complex activity in fowl

There is a notable discrepancy between the FAS (fatty acid synthase) activity of four types of fowl (egg chicken, meat chicken, egg duck, and meat duck) with distinctively different body fat levels. There is a 14.8 fold difference per unit body weight between the maximum and minimum FAS activities. The three major factors affecting this discrepancy are liver weight per unit body weight, which is 2.3 times greater in meat ducks than in egg chickens, the amount of FAS protein per gram of liver, which is 1.85 times greater in meat ducks than in egg chickens, and the FAS specific activity in meat ducks, which is 3.5 times greater in meat ducks than in egg chickens. Within the same species of egg chickens, the abdomen fat per kg of body weight at 470 days after egg production is 66 times greater than 90 days before egg production and the liver FAS activity is increased 9.6 fold. The 9.6 fold FAS activity increase resulted from an increase in the specific activity, since the liver weight per kilogram of body weight remained constant at approx. 20 grams and the FAS weight per gram of liver also remained constant at approx. 4.5 mg. This shows that the control of the basic FAS activity level which is closely related to the level of body fat does not mainly arise from genetic control. For the same kind of fowl, the control of the basic FAS activity level occurs after gene expression. It is suggested that control may be imposed in the folding phase when new peptides give rise to functional proteins.     

Strain differences in the dose-response curves of adrenalectomized, starved-refed rats to dehydroepiandrosterone (DHEA)

The effects of adrenalectomy and dehydroepiandrosterone (DHEA) doses (0, 15, 30, 60, 120 and 240 mg/kg/day ip) on hepatic enzyme activity and lipid content and on the amount of epididymal fat pad lipid were studied in starved-refed BHE and Sprague-Dawley rats. BHE rats had significantly greater relative liver size, glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) activities, and percentage liver lipid but less epididymal fat pad lipid than Sprague-Dawley rats. Adrenalectomized (ADX) rats consumed significantly less food, gained less weight per day, and had less lipid in their livers and fat pads than intact rats. As the level of DHEA increased from 0 to 240 mg/kg/day there was a significant linear decrease in average daily weight gain, food intake, G6PD activity, and percentage liver lipid. At the 15 mg/kg/day dose, G6PD activity was significantly reduced without reductions in the other parameters measured. At the 120 mg/kg/day dose, however, weight gain, food intake, G6PD activity, and percentage liver lipid were significantly lower than that of the controls. At this dose DHEA treatment reduced food intake by 17% whereas it diminished average daily weight gain and G6PD activity by 30 and 56%, respectively. The 240 mg/kg/day dose of DHEA significantly reduced food intake, weight gain, liver lipid, G6PD activity, and ME activity. Intact and ADX BHE rats reduced their G6PD activity and liver lipid more rapidly than Sprague-Dawley rats as the level of DHEA administered increased. ADX Sprague-Dawley rats receiving DHEA had greater liver lipid content and enzyme activity than their intact counterparts whereas the reverse situation was true in BHE rats. These data indicate that the effect of DHEA on body weight gain, food intake, and hepatic and peripheral adiposity are dependent on the strain of rat, the adrenal status, and the DHEA dose.     

Effects on animal growth and lipid composition of heart, liver, and adipose tissue in male rats fed different levels and types of fats

Weanling male rats were fed diets containing 5, 10, or 20% (by weight) fat. Diets were made isocaloric by decreasing the amount of starch as the diet fat level increased. At each fat level, three oil mixtures were fed which contained 13, 32, or 79% saturated fatty acids. The polyunsaturate level was 11% of total fatty acids in all mixtures. After 12 weeks, animals eating the high fat diets had gained significantly less weight and had eaten less feed. These animals also had significantly lighter livers and more liver lipids. The level and type of fat in the diet affected the amount (mg/g) of several phospholipids in the liver and heart. The fatty acid patterns (total saturates, n - 3, n - 6 fatty acids) of the major phospholipids were generally constant, the monounsaturated fatty acids being the major exception.     

布朗族成人的身体成分分析

本文采用生物阻抗分析法,研究了布朗族成人的体成分特点。我们在云南省测量了604例（男性248例,女性356例）布朗族成人19项身体成分指标,运用Excel 2003、Spss 19.0对其各项指标进行统计分析。结果显示,男性全身脂肪分布特征为躯干和下肢的脂肪率都大于上肢脂肪率,女性脂肪率从大到小依次为下肢、躯干、上肢;男、女性双侧下肢脂肪率和肌肉量接近,左上肢肌肉量低、脂肪率高;布朗族男性的身高、体质量、肌肉量、推定骨量、总能量代谢、水分率、内脏脂肪等级均大于女性,而体脂率、BMI小于女性。随着年龄的增长,布朗族成人身体肌肉量、骨量、下肢脂肪率、能量代谢等呈明显下降,而内脏脂肪等级明显增加。与云南汉族比较,布朗族成人的体脂率较低、肌肉较发达。     

Whole wheat versus mixed layer diet as supplementary feed to layers foraging a sequence of different forage crops

In many cases health and welfare problems are observed in organic egg production systems, as are high environmental risks related to nutrient leaching. These disadvantages might be reduced if the layers are allowed to utilise their ability to forage to a higher degree thereby reducing the import of nutrients into the system and stimulating the hens to perform a natural behaviour. However, very little is known about the ability of modern high-producing layers to take advantage of foraging to cover their nutritional needs, and the aim of the present work was to clarify this subject. Six flocks, each of 26 hens and one cock, were moved regularly in a rotation between different forage crops for a period of 130 days. Half of the flocks were fed typical layer feed for organic layers and half were fed whole wheat. The forage crops consisted of grass/clover, pea/vetch/oats, lupin and quinoa. At the beginning of the experiment, wheat-fed hens had a lower intake of supplementary feed (wheat) and a lower laying rate, egg weight and body weight. However, after a period of 6 to 7 weeks, the intake of wheat increased to approximately 100 g per hen per day and the laying rate increased to the same level as for the hens fed layer feed. For both groups of hens egg weight and body weight increased during the remaining part of the experiment. Crop analysis revealed different food preferences for hens fed layer feed and wheat-fed hens. Wheat-fed hens ate less of the cultivated seeds, whereas the amounts of plant material, oyster shells, insoluble grit stone and soil were larger in the crops from wheat-fed hens. Floor eggs were significantly more frequent in the hens fed layer feed, whereas wheat-fed hens only rarely laid floor eggs. Irrespective of treatment, hens were found to have excellent health and welfare. We conclude that nutrient-restricted, high-producing organic layers are capable of finding and utilising considerable amounts of different feed items from a cultivated foraging area without negative effects on their health and welfare.     

Hepatic and adipose tissue lipogenic enzyme mRNA levels are suppressed by high fat diets in the rat

Small changes in lipogenic enzyme activity induced by dietary fats of different composition may, over the long term, have significant impact on the development of obesity. We have investigated the effect of high fat diets (45% of calories as fat) on abundance of mRNA encoding fatty acid synthetase (FAS) and glycerophosphate dehydrogenase (GPDH) in male Sprague-Dawley rats. When caloric intake was equal, the relative amount of hepatic FAS mRNA was greater in rats fed a saturated compared to a polyunsaturated fat diet. This difference could not be attributed to diet-induced changes in plasma insulin concentration. However, both fat diets suppressed hepatic FAS mRNA compared to a sucrose diet. Close correlation between FAS specific activity and the relative amount of mRNA suggested that regulation was mainly at a pre-translational level. Adipose tissue FAS mRNA was suppressed by the two fat diets equally while GPDH mRNA was unaffected by dietary composition. Retroperitoneal fat pads were significantly larger in rats fed saturated compared to those fed polyunsaturated fat for 26 weeks. We concluded that dietary saturated fats fail to suppress hepatic de novo lipogenesis as effectively as polyunsaturated fats, which may have implications for the prevention of obesity in humans.     

何首乌提取物对脂肪酸合酶的抑制作用

最新报道脂肪酸合酶 (FAS)是治疗肥胖症的潜在靶部位 ,但目前已知的FAS抑制剂还很少 .测定表明 ,中药何首乌提取物对FAS同时具有很强的快结合可逆抑制和慢结合不可逆抑制作用 .萃取的最佳溶剂为 4 0 %乙醇水溶液 .该提取物对FAS全反应的半抑制浓度为 0 .0 0 5mg ml(以萃取时中药重量计 ) ;不可逆抑制过程为两相 ,在 0 4 6mg ml浓度下在 0 5min内快相失活超过 5 0 % ,慢相在 32min时失活达 90 % .该提取物对FAS中的酮酰还原反应有强抑制 ,半抑制浓度为 0 0 18mg ml,对烯酰还原反应有弱抑制作用 .抑制动力学分析表明 ,何首乌提取物对FAS的抑制和底物NADPH之间呈非竞争性关系 ,和丙二酰辅酶A接近竞争性关系 ,而与乙酰辅酶A为反竞争性关系 .推测何首乌还含有作用于FAS中的丙二酰转酰酶的抑制剂 .用何首乌提取物口服饲喂大鼠 ,可明显减低大鼠摄食量和降低大鼠体重 ;实验结束时实验组大鼠肝脏FAS活性低于对照组 .以上结果表明 ,中药何首乌提取物对FAS有很强的抑制作用 ,其抑制能力明显强于已知抑制剂 ,其动力学表现也和已知抑制剂完全不同 ,预计为新的抑制剂 ,对研究FAS的作用机理及在防治肥胖症的应用上可能具有重要的价值     

绵羊肌肉中FAS基因和HSL基因的发育性变化及其对肌内脂肪含量的影响

选取不同日龄的雄性哈萨克羊和新疆细毛羊共54只,屠宰后取背最长肌,用索氏抽提法检测肌内脂肪(intramuscular fat,IMF)含量,用荧光实时定量PCR法检测肌肉脂肪酸合成酶(fatty acid synthase,FAS)和激素敏感脂肪酶(hormone-sensitive lipase,HSL)基因表达的发育性变化,并分析基因表达对肌内脂肪沉积的影响。结果表明:1)随着日龄的增加,雄性哈萨克羊的IMF含量持续上升,各生长时期差异显著(P<0.05),而新疆细毛羊的IMF含量在各生长时期无显著差异(P>0.05)。雄性哈萨克羊的IMF含量30~90日龄期间极显著高于新疆细毛羊(P<0.01)。2)FAS基因mRNA水平在哈萨克羊肌肉中初生时最高(P<0.05),然后随日龄的增加呈下降趋势;在新疆细毛羊肌肉中,FAS mRNA水平表现出"下降-上升-下降-上升"的发育模式,其中60日龄显著高于90日龄(P<0.05),其余日龄之间差异不显著。HSL基因在2品种绵羊肌肉中的表达模式基本类似,在哈萨克羊肌肉中随年龄的增加而下降,初生时的水平显著高于60~90日龄(P<0.05);在新疆细毛羊中30日龄时达到最高(P<0.01),到60日龄时下降到最低(P<0.05),随后保持这种低表达水平。3)FAS和HSL基因mRNA的表达量均与哈萨克羊IMF含量呈负相关,相关系数分别为:r=-0.485(P=0.02),r=-0.423(P=0.05);在哈萨克羊中两基因表达量水平比值(FAS:HSL)与IMF呈极显著负相关r=-0.552(P=0.01)。在新疆细毛羊中两基因的表达水平及比值均与IMF无显著相关性(P>0.05)。     

Impact of an energy- and nutrient-reduced diet containing 10% lignocellulose on animal performance,body composition and egg quality of dual purpose laying hens

In response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.