Human bleomycin hydrolase regulates the secretion of amyloid precursor protein.

Human bleomycin hydrolase (hBH) is a neutral cysteine protease genetically associated with increased risk for Alzheimer disease. We show here that ectopic expression of hBH in 293APPwt and CHOAPPsw cells altered the processing of amyloid precursor protein (APP) and increased significantly the release of its proteolytic fragment, beta amyloid (Abeta). We also found that hBH interacted and colocalized with APP as determined by subcellular fractionation, in vitro binding assay, and confocal immunolocalization. Metabolic labeling and pulse-chase experiments showed that ectopic hBH expression increased secretion of soluble APPalpha/beta products without changing the half-life of cellular APP. We also observed that this increased Abeta secretion was independent of hBH isoforms. Our findings suggest a regulatory role for hBH in APP processing pathways.     

四川自贡大山铺成渝龟科—新属

描述了产自四川自贡大山铺恐龙化石坑中的三件龟甲标本,命名为一新属新种—周氏四川龟（Sichuanchelyschowigen．etsp．nov．）。该属以椎盾极横宽,中部缘盾极狭长为主要特征,它代表了成渝龟科中一类较特别的类型。     

玉米O2/o2近等基因系胚乳中基因表达差异分析

对玉米Hz85(O2/O2)和 Hz85(o2/o2)以及S7913(O2/O2)和 S7913 (o2/o2)两种不同核背景下的近等基因系(NIL),采用cDNA芯片杂交技术研究玉米o2突变基因及赖氨酸形成和胚乳发生相关基因在RNA水平上的表达差异。在两套NILs中检测到共同的表达差异克隆87个,对其序列分析得到26个TUGs（tentative unique genes）、11个未命名蛋白和6个新序列。这些TUGs分别参与了生长发育、胁迫响应、物质运输、信号转导、电子传递链、细胞防御、代谢等细胞过程,以及作为细胞组分和贮存蛋白。基于O2/o2 NILs间胚乳发育中基因表达的差异,讨论了o2籽粒中的不透明粉质胚乳形成的分子机制。     

GABA_B受体变构剂药学研究进展

γ-氨基丁酸B受体（GABAB receptor,GABABR）是最具有药理学意义的药物靶点之一,具有复杂而精细的激活机制。传统的GABABR靶点药物开发集中于激动剂和拮抗剂,这类药物受到多种因素的制约,包括较强的副作用、药物代谢困难、机体耐药性明显等。变构剂结合于正构位点之外,能够调节GABABR异源二聚体亚基或结构域间的相互作用。正向变构剂（positiveallosteric modulators,PAMs）和负向变构剂（negative allosteric modulators,NAMs）分别可以提高或降低GABABR的活性,并具有较高的特异性和药物安全性,同时还能够保持GABABR信号在时间和空间上的可控性。变构剂为GABABR靶点药物开发提供了新思路。     

湖南沅江鼎城段河蚬的性别组成与精子形态特征

本研究以湖南沅江鼎城段河蚬(Corbicula fluminea)为研究对象,在进一步验证该群体性别组成的基础上,分析壳长组成与性别比例之间关系,探讨该群体雄性、雌性和雌雄同体之间关系;同时以单鞭毛精子为参照,分析比较双鞭毛精子的形态特征,以期为我国河蚬的性别发生及生殖适应策略研究提供基础资料。结果显示：沅江鼎城段河蚬(n = 770)雄性、雌性和雌雄同体最小性成熟壳长分别为2.92 mm、5.66 mm和5.30 mm。697只性成熟河蚬中雄性、雌性和雌雄同体的比例近似1︰1︰6。雌雄同体的平均壳长[(22.55 ± 0.33)mm,n = 517]显著大于雄性[(20.44 ± 1.03)mm,n = 95]和雌性[(19.79 ± 0.99)mm,n = 85](P < 0.05),但雄性与雌性的平均壳长之间差异不显著(P > 0.05)。河蚬可以产生单鞭毛和双鞭毛两种类型的精子,单鞭毛精子头长范围4.93 ~ 21.79 μm,平均值(14.27 ± 0.82)μm(n = 30),双鞭毛精子头长范围10.29 ~ 22.04 μm,平均值(15.62 ± 0.62)μm(n = 26)。单、双鞭毛精子头长差异不显著(P > 0.05)。双鞭毛精子(n = 26)长尾的平均长度[(38.07 ± 1.44)μm]显著大于其短尾[(31.08 ± 1.60)μm]和单鞭毛精子(n = 30)尾部长度[(30.15 ± 1.75)μm](P < 0.01),但其短尾与单鞭毛精子的尾部平均长度之间无显著性差异(P > 0.05)。结果表明：湖南沅江鼎城段河蚬为雄性先熟,且可能存在雄性和(或)雌性向雌雄同体转换现象。河蚬具有单鞭毛型和双鞭毛型2种类型的精子,且双鞭毛精子的2个尾部不等长。同域共存河蚬的单鞭毛与双鞭毛精子在运动及受精能力方面的差异值得深入研究。     

机体胆汁酸肠-肝轴的研究进展

机体肠道与肝脏间的交互作用形成肠-肝轴,后者的紊乱是肝脏疾病发生的重要原因,而良好的肠道稳态和肝脏的保护对维持机体内环境的稳定起着重要作用。胆汁酸(胆盐)作为肠-肝轴循环中的重要组成成分,不仅参与了机体营养物质的消化代谢,还作为一种信号分子和代谢调节因子,能够激活核受体和G蛋白偶联受体(GPCR)信号通路参与调节肝脏脂质、葡萄糖和能量平衡,维持机体代谢平衡。本文将结合近年来有关胆汁酸的研究进展,从胆汁酸的来源、在肠-肝轴中的循环以及胆汁酸在机体中的作用等方面进行综述,以加深对肠-肝轴重要性的理解。     

Ant versus bird exclusion effects on the arthropod assemblage of an organic citrus grove

1. Predation‐exclusion experiments have highlighted that top‐down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. 2. We conducted 1‐year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. 3. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant‐excluded than in control trees, whereas only dermapterans were more abundant in bird‐excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. 4. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator–prey system.     

Apolipoprotein A-I directly interacts with amyloid precursor protein and inhibits A beta aggregation and toxicity

Amyloid precursor protein (APP) is the source of the neurotoxic amyloid beta (Abeta) peptide associated with Alzheimer's disease. Apolipoprotein A-I (apoA-I), a constituent of high-density lipoprotein complexes, was identified by a yeast two-hybrid system as a strong and specific binding partner of full-length APP (APPfl). This association between apoA-I and APPfl was localized to the extracellular domain of APP (APPextra). Furthermore, the interaction between apoA-I and APPfl was confirmed by coprecipitation using recombinant epitope-tagged APPextra and purified apoA-I. Several functional domains have been identified in APPextra, and we focused on a possible interaction between apoA-1 and the pathologically important Abeta peptide, because APPextra contains the nontransmembrane domain of Abeta. The binding between apoA-I and Abeta was saturable (K(d) = 6 nM), specific, and reversible. APPextra also competed with apoA-I for binding to Abeta. Direct evidence for this interaction was obtained by the formation of an SDS-resistant Abeta-apoA-I complex in polyacrylamide gels. Competitive experiments with apolipoprotein E (isoforms E2 and E4) showed that apoA-I had a higher binding affinity for Abeta. We also found that apoA-I inhibited the beta-sheet formation of Abeta with a mean inhibitory concentration close to that of alpha2-macroglobulin. Finally, we demonstrated that apoA-I attenuated Abeta-induced cytotoxicity. These results suggest apoA-I binds to at least one extracellular domain of APP and has a functional role in controlling Abeta aggregation and toxicity.     

鄂西大蓟根的化学成分的研究

本题对菊科蓟属植物鄂西大蓟根Cirsium henryi的化学成分进行系统研究。采用硅胶柱色谱法分离了五个单体成分并以光谱分析法鉴定它们的结构:乙酰丁香酸(p-Hydroxycinnamic acid,1),原儿茶酸(protocate-chuic acid,2),香草酸(vanillic acid,3),二羟丙基软脂酸酯(2,3-dihydroxypropyl hexadecanoate,4)和胡萝卜苷(glucoraphenin,5)。这些化合物均为首次从该植物中分离得到。     

B 超引导下子宫内膜消融术治疗更年期功血51 例临床分析

目的:探讨在B超引导下子宫内膜消融术治疗更年期功血的效果。方法:扩张宫颈至6.5号,吸宫,在B超监视下由子宫右前壁始向外刮凝,依次顺时针方向刮凝宫腔2周。结果:治愈31例(60.8%),有效19例(37.3%),好转1例(1.9%),无效0例。结论:电凝刀子宫内膜消融术与其他更年期功血治疗方法相比,消融的范围及深度由B超监视,安全性高,创伤小,不开刀,恢复快,并且治愈率高,更容易在临床上推广。