肥胖与减肥的分子生物学进展

肥胖已成为社会公共健康问题．随着细胞与分子生物学技术的发展和应用，c出基因、瘦素、瘦素受体及瘦素作用机制，解耦联蛋白分子及其解耦联作用机理，抵抗素基因、抵抗素分子及抵抗素的生物学效应等方面取得了重要进展，为运动减肥提供了新的科学理论依据．     

脂肪细胞因子及其在2型糖尿病中的作用与机制

脂肪组织不仅是储存脂肪的场所,还是一个功能活跃的内分泌器官,能分泌多种生物活性物质,这些物质统称为脂肪因子.其中有的是近几年发现的,有的则是早已发现但在最近几年才发现其在糖尿病中的作用.本文侧重对将其中的脂联素、内脏脂肪素、瘦素、肿瘤坏死因子α、抵抗素在2型糖尿病的病理生理过程中的一些作用及其机制进行探讨.     

瘦素对妊娠及胎儿发育的影响

瘦素(Leptin)是由脂肪组织分泌的激素,主要功能是调控进食、能量消耗及体重.近年来研究表明瘦素在青春发育期及期后维持下丘脑垂体性腺正常功能中起着重要的作用,同时发现瘦素与生殖也有密切的关系.文章就瘦素的基本结构与功能、瘦素受体,瘦素与妊娠及胎儿发育,瘦素与妊高症的关系做一综述.     

瘦素对ob/ob小鼠脂肪含量的影响

瘦素是由ob基因鳊码、在脂肪组织合成分泌的蛋白质类激素，主要功能是调控进食、能量度体重．瘦素和其他激素一样，需要与特异的受体结合才能发辉其生物学作用．瘦素的发现，为进一步研究肥胖的发生机制及预防和治疗肥胖开辟了一条崭新的途径，也对我们的科研工作提出了更高的要求．     

Srpr基因遗传变异Leu104Ser与小鼠血液胰岛素及瘦素水平关系的研究

目的:探讨信号识别颗粒受体(Srpr)基因遗传变异Leu104Ser与小鼠血液胰岛素及瘦素水平的关系。方法:在小鼠Srpr基因中寻找位于编码区的遗传变异,在14种品系共270只小鼠中分析该遗传变异与小鼠血液胰岛素及瘦素水平间的关联。进一步分析Srpr基因所在染色体区域(Chr9:34.6Mb～35.6Mb)所有基因在胰岛β细胞和脂肪细胞的表达情况,以进一步确定Srpr基因与小鼠血液胰岛素及瘦素水平的关联。结果:在小鼠Srpr基因中寻找编码区突变遗传变异Leu104Ser,携带104Ser遗传变异的小鼠血液胰岛素及瘦素水平明显升高(P值均<0.01)。并且Srpr基因是附近10Mb染色体区域唯一在胰岛β细胞和脂肪细胞高表达的基因。结论:Srpr基因遗传变异Leu104Ser与小鼠血液胰岛素及瘦素水平升高有关,提示Srpr基因可能参与肥胖及糖尿病的发生。     

运动对糖耐量减低患者血清抵抗素、脂联素和胰岛素敏感性的影响

探讨运动对糖耐量减低（IGT）患者血清抵抗素、脂联素和胰岛素敏感性的影响．56名中老年IGT患者随机分为3组：对照组（18例）、健步走组（19例）、健步走＋抗阻力组（19例）,健步走组采取24周健步走运动处方锻炼．健步走＋抗阻力组采取健步走和抗阻力运动相结合的运动处方锻炼,运动干预前后采用放射免疫法测定血清胰岛素、抵抗素、血清脂联素。计算胰岛素抵抗指数（HOMA-IR）．健步走组、健步走＋抗阻力组的抵抗素、脂联素和HOMA-IR与对照组相比均有极其显著性差异（P〈0．01）;健步走组与健步走＋抗阻力组的抵抗素和HOMA-IR与健步走组相比无显著性差异（P〉0．05）,脂联素比较有极其显著性差异（P〈0．01）．运动可改善IGT患者的代谢水平．健步走＋抗阻力运动对脂联素的影响较单纯健步走更为明显．     

线粒体解耦联蛋白2与能量代谢

通过资料收集法,综述了线粒体解耦联蛋白2（uncoupling protein2,UCP2）研究方面的进展.研究发现UCP2功能复杂,在自由基、胰岛素、脂肪酸代谢等生理活动中起影响作用,是能量代谢过程中的一种重要的蛋白。     

水杨酸信号分子在植物抗病反应中的作用

水杨酸是一个重要的能激活植物抗病防卫基因的信号分子.文章介绍了水杨酸的基本特性,生物合成及在植物抗病反应中的作用机理.     

脂联素基因及其在动物生产中的研究进展

脂联素是脂肪细胞所分泌的细胞因子,是迄今为止所发现的唯一与肥胖呈负相关的脂肪细胞因子,具有调节葡萄糖、脂肪酸代谢及调控生物体能量稳态等功能。现就脂联素的基因结构、生物学功能及其在动物生产中的研究进展作一综述。以期为动物分子育种研究提供新的思路。     

小麦多酚氧化酶研究进展

多酚氧化酶(polyphenol oxidase,PPO)是引起面条等面制食品颜色褐变的主要因素,研究小麦多酚氧化酶活性的遗传规律及其与面团色泽的关系对改良面粉色泽具有重要意义.多酚氧化酶活性是受多基因控制、且遗传力低的数量性状,易受环境条件影响,发掘可应用于小麦多酚氧化酶活性辅助选择的分子标记,将有助于小麦面粉颜色性状的遗传改良.本文综述了小麦多酚氧化酶的生理功能及作用机理,重点阐述了小麦多酚氧化酶的基因定位、分子标记及遗传分析对低多酚氧化酶活性小麦新品种选育及遗传研究的意义.     

固有无序蛋白质(IDPs)的预测和分子动力学模拟研究

固有无序蛋白质是一类在生理状态下没有固定三维结构,却可以发挥正常生物学功能的蛋白质.对这类蛋白质系统深入的研究丰富了人们对蛋白质生物学功能的认识.固有无序蛋白质预测经过十多年发展,已经成为发现新固有无序蛋白质的重要工具;而分子动力学模拟则为我们从微观上研究固有无序蛋白构象变化过程、分析固有无序蛋白与其他分子的相互作用,以及揭示这类蛋白质的特征等发挥了不可替代的作用.     

X-ray Crystallography of biological macromolecules

The three-dimensional structures of thousands of biological macromolecules have been determined by X-ray diffraction, since the first structures were reported about half a century ago. The structures revealed how critical the shapes and sizes of the molecules are to perform various biological processes in living creatures. In addition to providing atomic details of how the molecules function and interact with other molecules, the structures help in designing medicines. K Suguna is at the Molecular Biophysics Unit Indian Institute of Science Bangalore. Her research involves the determination of the crystal structures of macromolecules by the X-ray diffraction method. She is interested in the structures and functions of biological macromolecules.     

Investigation of structures similarity of organic substances

According to similarity property principle, structurally similar molecules tend to have similar properties. Similar molecules exhibit similar biological activities. However, there is no hard and fast rule that the compounds with similar chemical structure will have similar functions. There are several compounds of similar chemical structure with significantly different biological actions and activities. Structure similarity of natural products can be investigated using Tanimoto coefficient and Euclidean distance measurements. To do this, the molecules are decomposed into smaller fragments, and a dictionary, of the fragments are prepared. Using the dictionary, 2D fingerprints are formed. With the fingerprints Tanimoto coefficient and Euclidean distance are quantitated.     

Resistin levels of serum and follicular fluid in non-obese patients with polycystic ovary syndrome during IVF cycles

INTRODUCTION Polycystic ovary syndrome (PCOS) is a leading cause of anovulatory infertility and affects 5%~10% of reproductive age women (Dunaif, 1997). It is characterized by hyperandrogenemia and chronic anovulation and is associated with insulin resistance, obesity and increased risk for type 2 diabetes (Kno- chenhauer et al., 1998). Insulin resistance is thought to play an important role in aetiology of PCOS (Chang et al., 1983; Shoupe et al., 1983). In vitro and in vivo studies …     

Relationship between resistin level in serum and acute coronary syndrome or stable angina pectoris

Objective To investigate the relationship between serum resistin level and acute coronary syndrome (ACS) or stable angina pectoris (SAP). Methods Sixty-five patients, with coronary artery disease, were enrolled and divided into three subgroupsacute myocardial infarction (AMI), unstable angina pectoris (UAP) and SAP, and 26 healthy people were recruited as controls in the cross-sectional study. Serum resistin levels were determined by ELISA (enzyme-linked immunosorbent assay), and WBC (white blood cell count), hsCRP (high sensitive C-reaction protein), CKmax (maximum ofcreatinkinase), CK-MBmax (maximum of isozyme of creatinkinase) and cTnImax (maximum oftroponin) were measured by standard laboratory methods. Results The serum resistin levels were 4 folds higher in AMI patients, 2.43 folds in UAP patients and 1.12 folds in SAP patients than in the healthy controls (P＜0.05). The resistin levels were also significantly different between AMI [(8.16±0.79) ng/ml], UAP [(5.59±0.75) ng/ml]and SAP [(3.45±0.56) ng/ml] groups (P＜0.01); WBC, hsCRP, CKmax, CK-MBmax and cTnImax were significantly increased in AMI patients over UAP and SAP patients. Spearman analysis showed that serum resistin levels were positively correlated with WBC (r=0.412, P=0.046), hsCRP (r=0.427, P=0.037), CKmax, CK-MBmax and cTnImax (r=0.731, 0.678, 0.656; P＜0.01). ConclusionSerum resistin levels increased with inflammatory factors and myocardial impairment. The results suggest that human resistin might play an important role in the pathogenesis of atherosclerosis and AMI as an inflammatory factor.     

Effects of over-expressing resistin on glucose and lipid metabolism in mice

Resistin, a newly discovered peptide hormone mainly secreted by adipose tissues, is present at high levels in serum of obese mice and may be a potential link between obesity and insulin resistance in rodents. However, some studies of rat and mouse models have associated insulin resistance and obesity with decreased resistin expression. In humans, no relationship between resistin level and insulin resistance or adiposity was observed. This suggests that additional studies are necessary to determine the specific role of resistin in the regulation of energy metabolism and adipogenesis. In the present study, we investigated the effect of resistin in vivo on glucose and lipid metabolism by over-expressing resistin in mice by intramuscular injection of a recombinant eukaryotic expression vector pcDNA3.1-Retn encoding porcine resistin gene. After injection, serum resistin and serum glucose (GLU) levels were significantly increased in the pcDNA3.1-Retn-treated mice; there was an obvious difference in total cholesterol (TC) level between the experiment and the control groups on Day 30. In pcDNA3.1-Retn-treated mice, both free fatty acid (FFA) and high density lipoprotein (HDL) cholesterol levels were markedly lower than those of control, whereas HDL cholesterol and triglyceride (TG) levels did not differ between the two groups. Furthermore, lipase activity was expressly lower on Day 20. Our data suggest that resistin over-expressed in mice might be responsible for insulin resistance and parameters related to glucose and lipid metabolism were changed accordingly.     

Resistin levels of serum and follicular fluid in non-obese patients with polycystic ovary syndrome during IVF cycles

Objectives: To measure serum and follicular resistin, steroids hormone levels in women with PCOS (polycystic ovary syndrome) (BMI (body mass index)<25 kg/m²), to assess possible correlations of resistin to hormonal and metabolic parameters and to analyze the clinical outcomes of in vitro fertilization-embryo transfer (IVF-ET) in women with PCOS and tubal infertility. Study design: We analyzed the clinical outcomes of IVF-ET in women with PCOS (BMI<25 kg/m²) and tubal infertility during the years 2002 to 2004 and compared the serum and follicular fluid resistin levels, estradiol (E₂), progesterone (P), testosterone (T) levels in 20 PCOS and 20 healthy, age-matched women without PCOS during IVF-stimulated cycles. The correlations between the resistin levels and the outcomes of IVF-ET were evaluated. Results: No significant differences in resistin levels of either serum or follicular fluid between PCOS and control group were found. However, resistin levels in serum were higher than that in follicular fluid in both groups. Multiple regression analysis showed that resistin levels in serum did not correlate with BMI, estradiol, LH (luteinizing hormone) and insulin level in fasting blood. No significant correlations were found between follicular fluid reisistin levels and fertilization rate, implantation rate, clinical pregnancy rate or early miscarriage rate in both PCOS and control groups. Conclusion: Our results show that resistin does not have correlation with the hormonal and metabolic parameters as well as the outcomes of IVF. These data suggest that resistin is unlikely to be a local determinant factor in steroidogenesis and growth and maturation of oocytes during IVF-ET in lean women with PCOS.