黄土高原常见造林树种光合蒸腾特征

为改善黄土丘陵沟壑区水土流失现状,该区长期以来开展了大量的植被建设,但是,植物的适应性及生长状况如何,还不十分清楚。为探讨造林树种对环境的适应性,从光合、蒸腾和生理生态指标出发,对黄土高原3个主要退耕还林树种：刺槐、沙棘、山杏的适应性进行了研究,并对其适宜性进行了评价。研究结果表明：沙棘不同坡位最大净光合速率Pmax、光补偿点LSP较其它两个树种占明显优势,特别是在上坡位Pmax、LSP分别达到了22.8μmol·m^-2s^-1、520μmol·m^-2s^-1,具有较高的同化代谢能力,该物种较适应该地区的强光环境,适宜种植于阳坡或坡顶;山杏LSP相对较低,而表观量子效率α明显高于沙棘、刺槐,并在下坡位达到最大值0.069,说明它主要利用弱光进行光合作用,适宜种植于阴坡或坡脚等弱光环境中,但由于山杏水分利用效率WUE较低,可能对环境带来不良影响,山杏叶片含水量为65.1%,明显高于其它两个树种,而叶绿素含量仅为0.94mg/g与刺槐沙棘的2.34mg/g和2.00mg/g相差很大,这可能是导致其WUE较低的一个原因;刺槐在上坡位的光合生理参数与山杏相差不大,但是随坡位下降其α、净光合速率Pn较山杏明显偏低各个坡位受限明显,容易形成老头树。     

不同盐碱类型胁迫对红地球/贝达葡萄植株离子分布的影响

以盆栽红地球/贝达葡萄为试材,定量浇灌NaCl、Na₂SO₄、NaHCO₃、NH₄Cl和(NH₄)₂SO₄,筛选导致葡萄叶片黄化的盐、碱离子,研究不同盐碱类型胁迫对葡萄植株离子分布的影响.结果表明： NaHCO₃对植株影响最大,叶片在处理14 d时出现黄化症状,而NaCl和NH₄Cl处理28 d时出现黄化症状.NaHCO₃和NaCl处理均显著增加了植株各器官中Na^+含量,NaHCO₃处理根中Na⁺含量是对照的 6.4倍;这两种盐处理均降低了除叶片外其他器官中的K⁺含量,NaHCO₃处理显著降低了各器官中K/Na,根中K/Na仅为0.1,NaCl处理降低了除茎外其他器官中K/Na;这两种盐处理还降低了Ca²⁺、Mg²⁺、Fe²⁺向地上部的运输.NH₄Cl、(NH₄)₂SO₄和Na₂SO₄处理降低了植株各器官中K/Na,以NH₄Cl处理显著.碱性盐NaHCO₃对葡萄叶片黄化影响最大,其次是中性盐NaCl,再次是NH₄Cl,而(NH₄)₂SO₄和Na₂SO₄影响较小.     

5种光合细菌种间原生质体融合及优良农用融合子的筛选鉴定

处于对数生长期的光合细菌球形红假单胞菌(Rhodopseudomonassphaeroides)、沼泽红假单胞菌(Rhodopseudomonaspalustris)、嗜酸红假单胞菌(Rhodopseudomdnasacidophila)、深红红螺菌(Rhodospirarubrum)、万尼氏红微菌(Rhodomocrobiumvannielii),经溶菌酶(3mg/L)处理50min后,获得了它们的菌体形成的原生质体,其再生率分别为80%、71%、82%、61%、74%.取等量的亲本菌株在35%的PEG(MW6000)诱导下两两融合5min,共10种组合.其融合率为球×沼2.5×10-4、球×嗜2.1×10-4、球×深2.0×10-4、球×万2.1×10-4、沼×嗜2.8×10-4、沼×深2.4×10-4、沼×万2.6×10-4、嗜×深2.0×10-4、嗜×万2.3×10-4、深×万2.4×10-4.经影印法鉴定:形成的融合子可以分别生长于以相应的有机物为唯一碳源的培养基上,所有融合子体积均相当于两亲本株体积之和,融合子菌落形态特征介于两亲本株之间.从中随机挑选100个融合子,以辣椒苗作为靶标植物,从上述融合子中筛选到了1株具有显著促进作物生长、提高抗病性的融合子.     

蝉花虫草活性成分的抗惊厥作用

本研究采用活性追踪的方法,逐步从人工培养蝉花虫草分离获得A（50%乙醇回流提取）、B（膜分离）、C（大孔树脂洗脱）和D（Sephadex LH20柱纯化）等4种样品,单一化合物D纯度为98.62%,鉴定为N6‐(2‐羟乙基)腺苷[N6‐(2‐hydroxyethyl)‐adenosine,HEA]。研究各样品对戊四唑（pentylenetetrazol,PTZ）诱导的小鼠惊厥模型的影响,以及选择性腺苷A1受体（AA1R）拮抗剂DPCPX或选择性腺苷A2A受体（AA2AR）拮抗剂ZM241385对HEA作用的影响,并采用苏木精-伊红（hematoxylin-eosin,HE）染色、免疫组化（immunohistochemical,IHC）染色和蛋白质免疫印迹（Western blot,WB）等技术进一步探究HEA抗惊厥作用的机制。结果表明,各样品（i.p.）均有抗惊厥活性,HEA（40–60mg/kg,i.p.）能显著延长惊厥小鼠的存活时间和降低死亡率,DPCPX（2mg/kg,i.p.）能够拮抗HEA的抗惊厥作用,而ZM241385无此作用;HE、IHC和WB的结果进一步揭示DPCPX显著降低HEA的作用。综上所述,蝉花虫草的HEA具有抗惊厥作用,并且可能通过激活腺苷A1受体而起作用。     

湖北旋覆花化学成分的研究(英文)

从湖北旋覆花(Inula hupehensis)地上部分分离得到19个化合物,经波谱数据分析分别鉴定为9-羟基-百里香酚(1),8,10-去氢-β-羟基-百里香酚(2),2-羟基-4-甲基苯乙酮(3),8,9-双羟基-9-百里香酚(4),10-羟基-8,9-双氧亚异丙基百里香酚(5),8,10-二羟基-9-异丁酰百里香酚(6),8-羟基-9-异丁酰-10-(2-甲基丁酰)百里香酚(7),8,9,10-三羟基百里香酚(8),8-羟基-9,10-二异丁酰百里香酚(9),neoechinulin A(10),3-醛基吲哚(11),3-羟乙酰基吲哚(12),丁香酸(13),4,6-二羟基-2-甲氧基苯乙酮(14),7-甲氧基-8-羟基香豆素(15),6-甲氧基山奈酚(16),(+)-正丁香酯素(17),β-棕榈精(18)和豆甾醇(19)。除了化合物8和9外,其他化合物均为首次从该植物中分离得到。     

多重连接探针扩增方法在假肥大性肌营养不良产前基因诊断中的应用

假肥大性肌营养不良(Duchenne/Becker muscular dystrophy, DMD/BMD)是一种由于DMD基因突变导致的X连锁隐性致死性遗传病。目前没有有效的治疗方法。为建立一种既可以对携带者进行检测又可以进行产前基因诊断的方法, 文章联合应用多重连接探针扩增技术(Multiplex ligation-dependent probe amplification, MLPA)和短串联重复序列(Short tandem repeats , STR)为遗传标记连锁分析的方法对26例有高风险再生育患儿的假肥大性肌营养不良家系的孕妇通过羊水穿刺进行产前基因诊断。26例进行产前基因诊断的羊水标本中有7例诊断为男性患儿, 4例诊断为女性携带者。MLPA可以作为筛查DMD基因缺失和重复突变的首选方法。联合应用MLPA和STR连锁分析, 可以提高假肥大性肌营养不良的产前基因诊断率。     

Theoretical Insights into Catalytic Mechanism of Protein Arginine Methyltransferase 1

Protein arginine methyltransferase 1 (PRMT1), the major arginine asymmetric dimethylation enzyme in mammals, is emerging as a potential drug target for cancer and cardiovascular disease. Understanding the catalytic mechanism of PRMT1 will facilitate inhibitor design. However, detailed mechanisms of the methyl transfer process and substrate deprotonation of PRMT1 remain unclear. In this study, we present a theoretical study on PRMT1 catalyzed arginine dimethylation by employing molecular dynamics (MD) simulation and quantum mechanics/molecular mechanics (QM/MM) calculation. Ternary complex models, composed of PRMT1, peptide substrate, and S-adenosyl-methionine (AdoMet) as cofactor, were constructed and verified by 30-ns MD simulation. The snapshots selected from the MD trajectory were applied for the QM/MM calculation. The typical S_N2-favored transition states of the first and second methyl transfers were identified from the potential energy profile. Deprotonation of substrate arginine occurs immediately after methyl transfer, and the carboxylate group of E144 acts as proton acceptor. Furthermore, natural bond orbital analysis and electrostatic potential calculation showed that E144 facilitates the charge redistribution during the reaction and reduces the energy barrier. In this study, we propose the detailed mechanism of PRMT1-catalyzed asymmetric dimethylation, which increases insight on the small-molecule effectors design, and enables further investigations into the physiological function of this family.     

S-腺苷甲硫氨酸的研究现状及应用前景

介绍了S-腺苷甲硫氨酸的制备方法及稳定性研究现状,并对其临床应用及市场前景进行了分析。     

丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制。因此,这些抑制物的脱除即所谓的"脱毒"步骤是正常进行后续酶解和发酵的前提条件。我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究。丝状真菌A.resinae ZN1转化糠醛的降解代谢途径可以简述为:糠醛首先快速地转化为毒性较低的糠醇;在有氧条件下,糠醇又再度生成不致对微生物产生危害的低浓度糠醛,糠醛继续氧化为糠酸。推测糠酸可能继续进入TCA循环,进而完成糠醛的完全降解。研究结果为将来加快丝状真菌A.resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据。     

A novel RGD-toxin protein,Lj-RGD3, from the buccal gland secretion of Lampetra japonica impacts diverse biological activities

RGD (Arg-Gly-Asp) motif toxin proteins from snake venoms, saliva glands secretion of leech or tick have typical characteristics of inhibiting platelet aggregation, angiogenesis, and tumor growth. Here we report cloning and characterization of a novel RGD-toxin protein from the buccal gland of Lampetra japonica. In an attempt to study the activities of anticoagulant in the buccal gland secretion of L. japonica, we established buccal gland cDNA library and identified a gene encoding a predicted protein of 118 amino acids with 3 RGD motifs. The predicted protein was named Lj-RGD3. We generated the cDNA of Lj-RGD3 and obtained the recombinant protein rLj-RGD3. The polyclonal antibodies against rLj-RGD3 recognized the native Lj-RGD3 protein in buccal gland secretion in Western blot analyses. The biological function studies reveal that rLj-RGD3 inhibited human platelet aggregation in a dose-dependent manner with IC₅₀ value at 5.277 μM. In addition, rLj-RGD3 repressed bFGF-induced angiogenesis in the chick chorioallantoic membrane model. rLj-RGD3 also inhibited the adhesion of ECV304 cells to vitronectin. Furthermore, rLj-RGD3 induced apoptosis and significantly inhibited proliferation, migration, and invasion evoked by bFGF in ECV304 cells. Taken together, these results suggested that rLj-RGD3 is a novel RGD-toxin protein possessing typical functions of the RGD-toxin protein.