大菱鲆29个脂质代谢相关基因的组织表达

不同鱼类的脂肪组织分布模式具有高度多样性。大菱鲆具有相对特殊的脂质储存模式;鳍条附近皮下脂肪组织是其重要的脂肪存储部位。为了更好地了解大菱鲆的脂质代谢生理,本实验初步研究了29个脂质代谢相关基因在大菱鲆体内的组织表达,这些基因参与了脂肪生成、脂肪酸β氧化、甘油酯的生物合成和水解、脂质运输以及相关的脂代谢转录调控过程。从30尾鱼(10尾混样作为一个重复)中采集眼、鳃、脑、皮肤、肌肉、肝脏、胃、肾脏、脾脏、心脏、前肠、幽门盲囊、后肠、盲肠和脂肪等共15个组织样本进行qRT-PCR分析。结果显示,肠和脑中脂肪生成基因表达量高,肝脏和肌肉脂肪生成基因表达量低。肠内大部分载脂蛋白和脂质代谢相关转录因子的基因表达水平也较高。肌肉中脂肪酸β氧化相关基因的表达水平较低。细胞内甘油酯酶在脑、眼和心脏中高表达。研究表明,在大菱鲆体内,肠道可能不仅是脂质摄取的场所,也是大菱鲆体内重要的脂肪代谢器官。本研究为进一步探讨大菱鲆脂代谢特征及探索不同储脂类型鱼类中脂肪代谢的多样性提供了基础数据,也将有助于在分子水平上进一步研究鱼类的脂质代谢调节。

PPARγ的分子生物学及其作用

PPARγ是一种能调控参与脂肪细胞分化，脂质储存，胰岛素敏感的一大类基因表达的核受体，它能与其天然配基，如前列腺素J2，脂肪酸衍生物结合并被其活化，合成的配基：thiazolidinediones及非甾体类抗炎性药物是PPARγ的拮抗剂，最近的研究表明，这种核受体在调节糖尿病及肥胖的代谢，细胞周期调控，癌基因，炎症及动脉粥样硬化的形成中起着重要的作用。

Effects of Subcutaneous Fat Stores on Serum Phospholipids and Nonesterified Fatty Acid Lipid Fractions in Periparturient Dairy Cows

Negative energy balance in early lactating dairy cows results in a massive release of fatty acids （FA） into the blood in nonesterified fatty acids （NEFA） form. Large quantities of circulating NEFA may alter the serum FA profile of phospholipids （PL） fraction, which is responsible for cellular plasma membrane integrity and intercellular signaling. The objective of this study was to determine the effects of subcutaneous fat stores, as assessed by body condition score （BCS） on a scale of one to five, around the time of calving and the subsequent lipomobilization on FA profile of serum NEFA and PL lipid fractions, and on productive performance. Based on BCS, cows were retrospectively dichotomized into two groups： over-conditioned （BCS _〉 3.25） and control （BCS _〈 3.0）. 22 cows had serum samples obtained at -28, -7, 8, 18 and 28 d relative to parturition and analyzed for the FA profile of the NEFA and PL fractions. As expected, over-conditioned cows had greater total plasma NEFA concentrations and decreased dry matter intake. Milk yield and composition did not differ between groups. More importantly however, several FA in the NEFA fraction of plasma lipids varied significantly, including C14：1, C16：0, C18：0 and C20：3n3. In the PL fraction, other FA varied significantly by BCS around time of parturition, including C16：0, C17：0, total C18：2 cis, and C20：2. In summary, BCS did affect FA profile of serum NEFA and PL lipid fractions. This may have drastic consequences for circulating immune cells and their ability to fight infection by altering their FA profile.

Effect of Storage Time and Temperature on Phenolic, Flavonoid Contents and Antioxidant Properties of Milled Rice

The objective of this study was to determine the phenolic, flavonoid contents and amioxidant properties in the milled rice cv. Khaw Dawk Mali 105 during storage for 0-7 months at different temperatures. The total phenolic content of non-stored rice was 17.02 mg/g and 7-month stored rice at 25℃ was 6.07 ＋ 0.01 mg/g while storage for 7 months at 37 ℃, the phenolic contents was 7.29±0.35 mg/g. The total flavonoid content of non-stored rice was 13.26 ± 0.01 mg/g and 7 month stored rice at 25 ℃ was 6.74±0.01 mg/g while storage for 7 months at 37℃, the flavonoid content was 6.45 ± 0.12 mg/g. The antioxidant property determined by 1, 1-diphenyl-2-picrylhydrazyl （DPPH） radical expressed in the value of EC50 （DPPH） of non-stored rice was 0.27 mg/mL and 7-month stored rice at 25℃ was 12.15 mg/mL while storage for 7 months at 37℃, the antioxidant property was 6.34 mg/mL. The antioxidant property determined by lipid peroxidation expressed in the value of EC50 （lipid peroxidation） of non-stored rice was 0.12 mg/mL and 7 month stored rice at 25℃ was 1.18 rag/mL while storage for 7-months at 37 ℃, the antioxidant property was 1.10 mg/mL. The results showed that storage time at 25℃ and 37 ℃ caused decrease of extractable phenolic and flavonoid contents and antioxidant activities of the milled rice however 7-month stored milled rice at 37 ℃ milled rice at 25 ℃.

Cidea controls lipid droplet fusion and lipid storage in brown and white adipose tissue

Excess lipid storage in adipose tissue results in the development of obesity and other metabolic disorders including diabetes,fatty liver and cardiovascular diseases.The lipid droplet(LD)is an important subcellular organelle responsible for lipid storage.We previously observed that Fsp27,a member of the CIDE family proteins,is localized to LD-contact sites and promotes atypical LD fusion and growth.Cidea,a close homolog of Fsp27,is expressed at high levels in brown adipose tissue.However,the exact role of Cidea in promoting LD fusion and lipid storage in adipose tissue remains unknown.Here,we expressed Cidea in Fsp27-knockdown adipocytes and observed that Cidea has similar activity to Fsp27 in promoting lipid storage and LD fusion and growth.Next,we generated Cidea and Fsp27 double-deficient mice and observed that these animals had drastically reduced adipose tissue mass and a strong lean phenotype.In addition,Cidea/Fsp27 double-deficient mice had improved insulin sensitivity and were intolerant to cold.Furthermore,we observed that the brown and white adipose tissues of Cidea/Fsp27double-deficient mice had significantly reduced lipid storage and contained smaller LDs compared to those of Cidea or Fsp27single deficient mice.Overall,these data reveal an important role of Cidea in controlling lipid droplet fusion,lipid storage in brown and white adipose tissue,and the development of obesity.

The size matters： regulation of lipid storage by lipid droplet dynamics

Adequate energy storage is essential for sustaining healthy life. Lipid droplet （LD） is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways： neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.