Two new dianthramide glucosides with cardiomyocytes protective activity from Aconitum carmichaelii

Two new dianthramide glucosides, N-(2′-β-d-glucopyranosyl-5′-hydroxysalicyl)-4-hydroxy-3-methoxyanthranilic acid methyl ester (1) and N-(2′-β-d-glucopyranosyl-5′-hydroxysalicyl)-4-hydroxyanthranilic acid methyl ester (2), together with five known glycosides, were isolated from the lateral roots of Aconitum carmichaelii. Their structures were elucidated by spectroscopic analyses. In the in vitro assays, compounds 1 and 2 showed activity against pentobarbital sodium-induced cardiomyocytes damage by recovering beating rhythm and increasing the cell viability.     

miR-22 regulates C2C12 myoblast proliferation and differentiation by targeting TGFBR1

Recently, miR-22 was found to be differentially expressed in different skeletal muscle growth period, indicated that it might have function in skeletal muscle myogenesis. In this study, we found that the expression of miR-22 was the most in skeletal muscle and was gradually up-regulated during mouse myoblast cell (C2C12 myoblast cell line) differentiation. Overexpression of miR-22 repressed C2C12 myoblast proliferation and promoted myoblast differentiation into myotubes, whereas inhibition of miR-22 showed the opposite results. During myogenesis, we predicted and verified transforming growth factor beta receptor 1 (TGFBR1), a key receptor of the TGF-β/Smad signaling pathway, was a target gene of miR-22. Then, we found miR-22 could regulate the expression of TGFBR1 and down-regulate the Smad3 signaling pathway. Knockdown of TGFBR1 by siRNA suppressed the proliferation of C2C12 cells but induced its differentiation. Conversely, overexpression of TGFBR1 significantly promoted proliferation but inhibited differentiation of the myoblast. Additionally, when C2C12 cells were treated with different concentrations of transforming growth factor beta 1 (TGF-β1), the level of miR-22 in C2C12 cells was reduced. The TGFBR1 protein level was significantly elevated in C2C12 cells treated with TGF-β1. Moreover, miR-22 was able to inhibit TGF-β1-induced TGFBR1 expression in C2C12 cells. Altogether, we demonstrated that TGF-β1 inhibited miR-22 expression in C2C12 cells and miR-22 regulated C2C12 cell myogenesis by targeting TGFBR1.     

Ecological restoration and factors regulating phytoplankton community in a hypertrophic shallow lake,Lake Taihu,China

A restoration program for the control of cyanobacterial blooms and the re-establishment of submerged macrophytes was conducted in Meiliang Bay of Lake Taihu since 2003. The effect of this ecological projects on plankton community and water quality, and factors regulating phytoplankton community were investigated in 2005. In general, some improvements of water quality occurred in the ecological restoration region, especially in the region of restoring aquatic macrophytes, where we detected significant reduction of nutrients. However, it seems the abundance of phytoplankton cannot be effectively control by the present ecological engineering. The phytoplankton abundance was high in the target restoration zone. Results of CCA and correlation analysis indicate that the phytoplankton community was mainly controlled by physico-chemical factors. Cyanobacteria species were positively related with pH, temperature, TP and TSS, while negatively related with TN, TN/TP and conductivity. The most discriminant variable was TN/TP, which explained 15% of the total variance of phytoplankton. However, TN was more important for the fluctuation of TN/TP than TP. It suggested that TN may be the ultimate factor controlling the phytoplankton community in Lake Taihu. Variation partitioning analysis showed that the pure contribution of crustacean was low for the variation of phytoplankton, suggesting that top-down control by crustacean zooplankton was weak in Lake Taihu. In general, this study suggested the reduction of nutrient load should be more important than top-down control using zooplankton for the ecosystem restoration in Lake Taihu.     

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)。     

同位素示踪技术在丛枝菌根真菌生态学研究中的应用

丛枝菌根(arbuscular mycorrhizal,AM)真菌是生态系统中重要的土壤微生物之一。AM真菌菌丝体网络是由AM真菌菌丝体在土壤生态系统中连接两株或两株以上植物根系所形成的菌丝体网络。随着菌根学研究的深入,如何直观的揭示AM真菌的生态学功能已经成为相关领域关注的热点问题。研究发现,利用同位素示踪技术可以开展AM真菌与宿主植物对土壤矿质营养的吸收、转运等方面的研究,以及菌丝体网络对不同宿主植物之间营养物质的分配研究和AM真菌在生态系统生态学中的功能研究。基于此,为了阐明同位素示踪技术在AM真菌研究中的价值,围绕菌根学最新研究进展,系统回顾了利用同位素示踪技术探究AM共生体对不同元素吸收和转运的机制、同位素示踪技术在AM真菌菌丝体网络研究中的价值和利用同位素示踪技术研究AM真菌在生态系统中的功能,为AM真菌生态学功能的研究提供理论基础,并对本领域未来的研究方向和应用前景进行展望。     

CDK5-Mediated Phosphorylation-Dependent Ubiquitination and Degradation of E3 Ubiquitin Ligases GP78 Accelerates Neuronal Death in Parkinson’s Disease

The molecular mechanisms responsible for the loss of dopaminergic neurons in Parkinson’s disease (PD) remain obscure. Loss of function of E3 ubiquitin ligases is associated with mitochondria dysfunction, dysfunction of protein degradation, and α-synuclein aggregation, which are major contributors to neurodegeneration in PD. Recent research has thus focused on E3 ubiquitin ligase glycoprotein 78 (GP78); however, the role of GP78 in PD pathogenesis remains unclear. Notably, cyclin-dependent kinase 5 (CDK5) controls multiple cellular events in postmitotic neurons, and CDK5 activity has been implicated in the pathogenesis of PD. Thus, we addressed the relationship between CDK5 and GP78 in MPTP-based PD models. We found that GP78 expression is decreased in MPTP-based cellular and animal PD models, and CDK5 directly phosphorylated GP78 at Ser516, which promoted the ubiquitination and degradation of GP78. Importantly, overexpression of GP78 or interference of GP78 Ser516 phosphorylation protected neurons against MPP⁺-induced cell death. Thus, our research reveals that the CDK5-GP78 pathway is involved in the pathogenesis of PD and could be a novel candidate drug target for the treatment of PD.     

Cyanidin-3-glucoside, a natural product derived from blackberry, exhibits chemopreventive and chemotherapeutic activity

Epidemiological data suggest that consumption of fruits and vegetables has been associated with a lower incidence of cancer. Cyanidin-3-glucoside (C3G), a compound found in blackberry and other food products, was shown to possess chemopreventive and chemotherapeutic activity in the present study. In cultured JB6 cells, C3G was able to scavenge ultraviolet B-induced *OH and O2-* radicals. In vivo studies indicated that C3G treatment decreased the number of non-malignant and malignant skin tumors per mouse induced by 12-O-tetradecanolyphorbol-13-acetate (TPA) in 7,12-dimethylbenz[a]anthracene-initiated mouse skin. Pretreatment of JB6 cells with C3G inhibited UVB- and TPA-induced transactivation of NF-kappaB and AP-1 and expression of cyclooxygenase-2 and tumor necrosis factor-alpha. These inhibitory effects appear to be mediated through the inhibition of MAPK activity. C3G also blocked TPA-induced neoplastic transformation in JB6 cells. In addition, C3G inhibited proliferation of a human lung carcinoma cell line, A549. Animal studies showed that C3G reduced the size of A549 tumor xenograft growth and significantly inhibited metastasis in nude mice. Mechanistic studies indicated that C3G inhibited migration and invasion of A549 tumor cells. These finding demonstrate for the first time that a purified compound of anthocyanin inhibits tumor promoter-induced carcinogenesis and tumor metastasis in vivo.     

柞蚕热休克蛋白70基因的克隆和序列分析

HSP70蛋白是受热等因素刺激后而诱导产生的蛋白质,是热休克蛋白家族中最重要的一员。采用RT-PCR方法克隆了柞蚕(Antheraea pernyi)热休克蛋白70基因(HSP70)的ORF序列(GenBank登录号:GU945199),该片段的序列长度为1905bp。生物信息学分析表明,该序列共编码634个氨基酸,预测蛋白的等电点和分子量大小分别为5.62kD和69.5kD。具有HSP70的保守性结构特征,与天蚕(Antheraea yamamai)、家蚕(Bombyx mor)、甘蓝夜蛾(Mamestra brassicae)、棉铃虫(Heliothis viriplaca)、甜菜夜蛾(Spodoptera exigua)、烟草夜蛾(Manduca sexta1)、膜翅目寄生蜂(Cotesia rubecula)的同源性分别为95.7%、78.5%、76.1%、77.3%、76.6%、74.7%、65.9%。根据它们的一级结构构建了系统进化树,进一步确立了它们之间的亲缘关系。     

钼,铁,硫化合物激活曝氧的棕色固氮菌固氮酶钼铁蛋白的研究

曝氧后,棕色固氮菌(Azotobacter vinelandii)固氮酶钼铁蛋白的催化活性和圆二色信号都显著降低,而吸收光谱则显著增加。与钼、铁、硫化合物和二硫苏糖醇组成的重组溶液保温后,曝氢蛋白的圆二色信号和吸收光谱几乎完全恢复至天然状态的同时,乙炔还原活性也得到了显著的恢复,表明重组溶液可使曝氧蛋白中的 P-cluster和其它活性部位都得到了不同程度的修复。     

抗呼吸道合胞病毒(RSV)单克隆抗体的制备及其对RSV病毒株抗原性的分析

用呼吸道合胞病毒R6(武汉地方株)活毒滴鼻加用戍二醛固定的病毒感染的Hela细胞免疫BALB/C鼠,取脾细胞与小鼠骨髓瘤SP_2/0细胞融合,培育出分泌抗呼吸道合胞病毒单克隆抗体的杂交瘤细胞13株,这些细胞的染色体数为94至104条,其分泌的抗体分别属于鼠IgC_1、IgG_(2a)、IgG_(2b)亚类。腹水荧光抗体滴度为1:10000～1:100000。其中五株单抗有中和病毒作用,尤其是两株中和放价达1:128。应用免疫转印法证实了这些单抗分别能识别RSV6种主要结构蛋白,用7株识别不同病毒结构蛋白的单抗对12株合胞病毒进行抗原性分析,可将这些病毒区分为二个血清型,即A亚型和B亚型。