‘红颜’草莓菌根磷转运蛋白基因的克隆及荧光定量表达分析

 采用MEGA5.0 软件对9 个森林草莓无机磷转运蛋白序列及58 个已知的其它植物磷转运蛋 白的氨基酸序列进行聚类分析,发现5 个基因与菌根磷转运蛋白基因分支聚在一起,初步判断是候选的 草莓菌根磷转运蛋白。根据其基因序列设计引物获得了5 个‘红颜’草莓候选菌根磷转运蛋白基因全长。 实时荧光定量PCR 结果表明,FaPT4、FaPT5 和FaPT8 在草莓菌根中显著上调表达,结合聚类分析结果, 证明这3 个基因是‘红颜’草莓菌根磷转运蛋白基因。     

藜麦活性成分研究进展

藜麦是苋科藜属一年生双子叶植物, 作为一种营养价值突出的功能性健康食品, 不仅富含多酚、黄酮、皂苷、多糖、多肽、蜕皮激素等活性成分, 还含有丰富的维生素、必需氨基酸、矿物质(K、P、Mg、Ca、Zn、Fe)等营养物质, 具有均衡补充营养、增强机体功能、抗氧化、降血糖、降血脂、抗炎、提高免疫、防治心血管疾病以及抗菌抗溃疡等生理活性, 尤其适于高血糖、高血压、高血脂、心脏病等慢性病人群及婴幼儿、孕产妇、儿童、学生、老年人等人群食用。藜麦因其全面的营养价值和食用功能特性, 且优于大多数谷物, 成为适宜人类食用的全营养食品。本文综述藜麦的活性成分及其生理功能作用, 并展望其在食品工业中的发展前景, 旨在对藜麦产业、食品保健和医药研发等领域提供重要的参考价值。     

对马铃薯类受体激酶CRK基因家族的鉴定及响应病原真菌信号的表达分析

富含半胱氨酸的类受体激酶(cysteine-rich receptor-like kinase,CRK)在植物生长发育和环境适应过程中发挥重要的作用。本研究鉴定了马铃薯CRK(StCRK)家族成员,并对其理化性状、进化特征、亚细胞定位、染色体位置和表达模式进行分析。鉴定获得8个StCRKs,其氨基酸序列大小为459~686 aa,分子量介于50.75~77.50 kD,等电点介于5.84~8.75,主要位于质膜。进化分析将来自马铃薯、拟南芥、香蕉、苹果、水稻、番茄和棉花的CRKs分为9个亚组,2号、3号和5号染色体上的StCRKs分布于亚组I(6个成员)和VI(2个成员);存在2个串联重复基因簇,包含4个成员。StCRKs启动子区域存在多种顺式调控元件,主要响应激素、低温、防卫和逆境等信号。接种晚疫病菌(Phytophthora infestans,Pi)和干腐病菌(Fusarium sulphureum,Fs)后,分别发现8个和6个StCRKs为差异表达。其中,StCRK4和StCRK8响应Pi和Fs信号,在接种以上2种病原菌后,表达量上调8倍以上,推测其响应多个真菌信号,可能在马铃薯对真菌病害的广谱抗性中起重要作用,可作为进一步抗病研究和功能分析的候选基因。     

Preventive effects of taurine on development of hepatic steatosis induced by a high-fat/cholesterol dietary habit

Nonalcoholic fatty liver (NAFL) is also called hepatic steatosis and has become an emergent liver disease in developed and developing nations. This study was to exam the preventive effects of taurine (Tau) on the development of hepatic steatosis via a hamster model. Although hepatic steatosis of hamsters was induced by feeding a high-fat/cholesterol diet, drinking water containing 0.35 and 0.7% Tau improved (p < 0.05) the serum lipid profile. Meanwhile, the smaller (p < 0.05) liver sizes and lower (p < 0.05) hepatic lipids in high-fat/cholesterol dietary hamsters drinking Tau may be partially due to higher (p < 0.05) fecal cholesterol, triacylglycerol, and bile acid outputs. In the regulation of lipid homeostasis, drinking a Tau solution upregulated (p < 0.05) low-density lipoprotein receptor and CYP7A1 gene expressions in high-fat/cholesterol dietary hamsters, which result in increased fecal cholesterol and bile acid outputs. Drinking a Tau solution also upregulated (p < 0.05) peroxisome proliferator-activated receptor-α (PPAR-α) and uncoupling protein 2 (UPC2) gene expressions in high-fat/cholesterol dietary hamsters, thus increasing energy expenditure. Besides, Tau also enhanced (p < 0.05) liver antioxidant capacities (GSH, TEAC, SOD, and CAT) and decreased (p < 0.05) lipid peroxidation (MDA), which alleviated liver damage in the high-fat/cholesterol dietary hamsters. Therefore, Tau shows preventive effects on the development of hepatic steatosis induced by a high-fat/cholesterol dietary habit.     

Effects of polyphenolic compounds on tumor necrosis factor-α (TNF-α)-induced changes of adipokines and oxidative stress in 3T3-L1 adipocytes

Over the last few decades, obesity has become a global epidemic in both developed and developing countries. Recent studies have indicated that obesity is closely associated with chronic inflammation characterized by abnormal levels of adipocytokines and inflammatory cytokines in adipocytes. The aim of this work was to study the effects of 21 polyphenolic compounds on tumor necrosis factor-α (TNF-α)-induced changes of adipokines and oxidative stress in 3T3-L1 adipocytes. The results showed that p-coumaric acid, quercetin, and resveratrol have greater inhibition (p < 0.05) of a TNF-α-induced increase in the production of interleukin-6 (IL-6) among 21 tested polyphenolic compounds. p-Coumaric acid, quercetin, and resveratrol demonstrated inhibitions of TNF-α-induced changes in levels of monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1), and intracellular reactive oxygen species (ROS) in 3T3-L1 adipocytes. Furthermore, p-coumaric acid, quercetin, and resveratrol increased levels (p < 0.05) of secreted adiponectin, superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and glutathione S-transferase (GST) in TNF-α-treated 3T3-L1 adipocytes. These results indicate that the inhibition of TNF-α-induced changes of adipokines and oxidative stress by some polyphenolic compounds might have further implications in preventing obesity-related pathologies.     

Gelation of protein recovered from whole Antarctic krill (Euphausia superba) by isoelectric solubilization/precipitation as affected by functional additives

This study demonstrated that the novel isoelectric solubilization/precipitation can be applied to recover functional muscle protein in a continuous mode from whole Antarctic krill. Protein recovered from whole krill had a much lower ash content than whole krill, suggesting good removal of inedible impurities (shell, appendages, etc.). Lipids were retained to a higher degree with krill protein solubilized at acidic rather than basic pH. The viscoelastic modulus (G') showed that recovered krill protein failed to form heat-induced gel unless beef plasma protein (BPP) was added. Therefore, protease inhibitors are suggested for development of krill-derived products. Even with BPP, the G' decreased between 45 and 55 degrees C. However, krill protein solubilized at acidic pH had a higher decrease of the G' than the protein solubilized at basic pH, likely due to krill endogenous cathepsin L. Krill protein-based gels developed from protein solubilized at basic pH, especially pH 12.0, had better texture (torsion and Kramer tests and texture profile analysis) than acidic counterparts, possibly due to higher proteolysis and denaturation at acidic pH. Gels made from protein solubilized at acidic pH were brighter and whiter likely due to a higher lipid content.     

Distinctive antioxidant and antiinflammatory effects of flavonols

The antioxidant and antiinflammatory effects of flavonols have been suggested to be structure-related. Results revealed that selected flavonols, including fisetin (F), kaempferol (K), morin (MO), myricetin (MY), and quercetin (Q), exhibited distinctive free radical scavenging properties against different kinds of free radicals. The H donation (DPPH bleaching) potential was Q > F approximately equals MY > MO > K, indicating that the presence of a 3',4'-catechol moiety in the B ring correlated with high activity. The 4'-OH in the B ring was suggested to be important for reducing xanthing/xanthine oxidase-generated superoxide; while an additional OH moiety on the ortho sites (3' or 5') attenuated the effect as the observed inhibitory potency was K approximately equals MO > Q > F > MY. The relative inhibitory effect for Fenton-mediated hydroxyl radical was K approximately equals MO approximately equals Q > F > MY. This result implies the involvement of 4-keto, 5-OH region in Fe++ chelating and the negative effect of pyrogallol moiety in the B ring. Similar to the inhibitory activity against a N-formyl-methionyl-leucyl-phenylalanine (f-MLP)-stimulated oxidative burst in human polymorphonuclear neutrophils (PMN), our result showed that the structural peculiarity of the di-OH in the B ring obviously rendered F, Q, and MO more potent as ROS inhibitors than MY and K, which have tri- and mono-OH in the B ring, respectively. All of the previous data indicated that the structure prerequisite to reinforce the free radical scavenging activity varies with the type of free radical. We further analyzed the effects of flavonols on nitric oxide (NO) production in endotoxin-stimulated murine macrophages, RAW264.7 cells. Results showed that all flavonols (up to 10 microM) inhibited NO production without exerting detectable cytotoxicity. F, K, and Q dose-dependently repressed iNOS mRNA expression and prostaglandin E2 (PGE2) production, in part through an attenuating NF-kappaB signaling pathway. This result indicates that flavonols, despite structural similarity, have different antioxidant and antiinflammatory effects.     

沟垄覆膜对连作马铃薯土壤酶活性、理化性状及产量的影响

以当地主栽品种"新大坪"为试验材料,采用大田定位试验,研究了平畦不覆膜(CK)、平畦覆膜(T1)、全膜垄播(T2)、全膜沟播(T3)、半膜垄播(T4)、半膜沟播(T5)6种栽培模式对连作马铃薯土壤酶活性、理化性状及产量的影响。结果表明,沟垄覆膜栽培可不同程度提高马铃薯连作田土壤过氧化氢酶、脲酶、碱性磷酸酶的活性,其中T2对3种酶活性的提高效果最为显著;沟垄覆膜可降低土壤pH,从而改善马铃薯根际土壤的理化性状,且以T2对土壤化学性质的改善最为明显,沟垄覆膜可不同程度提高土壤电导率;此外,沟垄覆膜栽培还可以显著提高马铃薯块茎的产量,其中T2增产幅度最高可达75%。本研究以期为半干旱地区马铃薯连作障碍的克服及提高马铃薯产量提供理论依据。