两种不同训练时程方法对海马损伤大鼠水迷宫成绩的影响

为探讨训练时程对大鼠水迷宫成绩的影响,采用直流电解法建立双侧背侧海马损伤大鼠模型,并通过5d(5dtraining)和7d训练(7dtraining)两种不同时程法检测海马损伤大鼠的空间学习记忆能力。结果表明,两种训练法均反映大鼠空间学习能力减退,而在检测空间记忆障碍时则略有不同。与5d训练法相比,7d训练法不仅显示大鼠穿台次数下降,且其在目标象限中的停留时间百分比亦下降。     

Disruption of the tryptophan binding site in the human serum albumin dimer

Monomer and dimer fractions of human serum albumin (HSA) obtained from charcoal-treated Fraction V HSA have very similar fluorescence and circular dichroism spectra, but the dimer neither binds l-tryptophan nor reacts rapidly with p-nitrophenyl acetate. The latter reaction presumably occurs in a major binding site of the monomer as many strongly bound ligands including l-tryptophan, small fatty acid anions (e.g., S.-W. M. Koh and G. E. Means, 1979, Arch. Biochem. Biophys.192, 73–79), and several drugs (e.g, N. P. Sollenne and G. E. Means, 1979, Mol. Pharmacol.15, 754–757) all decrease rates of reaction in direct proportion to their concentration. Binding data for those ligands indicate the presence of less than one binding site per molecule of charcoal-treated Fraction V HSA, and thus appear to reflect only its content of albumin monomer. The absence of that binding site in the dimer may reflect its inclusion within the dimer interface.     

Epidermal growth factor up-regulates the expression of nestin through the Ras-Raf-ERK signaling axis in rat vascular smooth muscle cells

The contractile-synthetic phenotypic modulation of vascular smooth muscle cells (VSMCs) is a key event during atherosclerosis progression. Although many studies have reported possible cytokines and growth factors implicated to this process, the critical factors affecting the VSMC phenotype remain unclear due to the lack of early de-differentiation marker identifications. In this study, we showed that nestin, an intermediate filament protein, is expressed in primary cultures of rat VSMCs representing the synthetic phenotype and its expression is diminished as these cells re-differentiate after serum deprivation. However, the regulation of nestin expression was never reported despite its common usage as an early differentiation marker. Herein, we showed that nestin expression is regulated by epidermal growth factor (EGF) via de novo RNA and protein synthesis. Furthermore, signaling analyses revealed that the EGF-induced nestin re-expression is mediated through the activation of the Ras-Raf-ERK signaling axis. This is the first report to show that nestin expression is regulated by an extracellular signaling molecule.     

中国梨木虱若虫的排蜜规律及蜜露中氨基酸成分的研究

本文研究了中国梨木虱 Psylla chinensis Yang et Li若虫期的排蜜规律及蜜露中氨基酸成分。结果表明 ,若虫随着龄期的增大 ,体重增加 ,日平均排蜜量也不断增多 ,每头夏型若虫一生排蜜量为630 3.38μg。在室内条件下 ,若虫排蜜量与昼夜节律有关 ,夜间排蜜量为一昼夜的 2 / 3。温度对若虫排蜜量有一定影响 ,在 2 5℃条件下排蜜量最大。若虫蜜露中氨基酸含量为 4 .4 5% ,其中天门冬氨酸和谷氨酸含量较高 ,分别占所测定的 17种氨基酸的 4 2 .11%和 2 7.5% ,蜜露中氨基酸的种类及含量与其所寄生的梨树叶片中氨基酸的种类及含量有密切关系     

Intergeneric Somatic Hybrid Plants Between Citrus and Poncirus trifoliata and Evaluation of Their Root Rot Resistance

Protoplasts of Page tangelo (Citrus reticulata Blanco×C. paradisi Macf.) cell suspension culture were electrically fused with mesophyll protoplasts isolated from trifoliate orange (Poncirus trifoliata (L.) Raf.). More than 150 plantlets regenerated after 4-5 months of culture. The regenerated plants were trifoliate with well developed root systems. Root-tip chromosome counting of more than 20 randomly selected plants revealed that they were all tetraploids (2n=4x=36). RAPD analysis of 7 randomly selected plants verified their hybridity. Inoculation of citrus Phytophthora parasitica Dastar toxin on leaves of somatic hybrids and both parental genotypes showed that Page tangelo was moderately susceptible, and trifoliate orange was highly resistant while the somatic hybrids were resistant. The potential of this somatic hybrid as rootstock is also discussed.     

斑马鱼socs2的TALEN敲除及其敲除胚胎的生长研究

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The various effects of fractionated oxidized low density lipoproteins on the growth of smooth muscle cells in culture

The effects of fractionated oxidized low density lipoproteins (oxidized LDL) on the growth of vascular smooth muscle cells (VSMC) and their relationship to the formation of lysophosphatidylcholine (lyso-PC) as well as the activation of protein kinase C (PKC) were studied. VSMC were isolated from porcine aorta by explant culture. LDL was isolated from porcine blood by sequential ultracentrifugation and oxidized LDL was obtained by incubating LDL with 5 µM CuSO₄ at 37° C for various lengths of time. Our results showed that LDL oxidized for 12 h and eluted from fast protein liquid chromatography at 43 min inhibited the growth of VSMC, and that LDL oxidized for longer than 48 h and eluted at 48 min stimulated the growth of VSMC. The formation of lyso-PC in the oxidized LDL correlated well with its stimulatory effect, suggesting that lyso-PC is responsible for the mitogenic effect of oxidized LDL. This stimulatory effect of oxidized LDL was inhibited by staurosporine, a PKC inhibitor. Treatment with oxidized LDL increased the activity of membrane PKC, but it decreased that of cytosolic PKC, suggesting the translocation of PKC from cytosol to the membrane in the presence of oxidized LDL. These results suggested that the oxidized LDL-stimulated VSMC growth was mediated by the formation of lyso-PC and the activation of PKC.     

植物种质离体保存技术研究进展

本文综述了国内外植物种质离体保存技术最新研究进展。科学家们已发展了一系列行之有效的离体保存技术体系,进一步建立长期、安全、适用的离体保存技术体系及探索保存过程中遗传变异情况是今后的重要研究方向。