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991.
为了创制OsBTF3基因沉默的水稻植株、验证该基因在水稻籽粒相关性状中的功能、评价其在水稻遗传改良中潜在的应用价值,设计和合成OsBTF3基因序列的引物、扩增部分基因片段,构建RNAi基因沉默载体、通过农杆菌介导转化愈伤组织、植株再生、潮霉素抗性筛选和PCR验证、定量分析OsBTF3基因表达量,测定转基因水稻籽粒相关性状。结果表明,成功地获得了20个T1代OsBTF3-RNAi转基因株系,OsBTF3基因表达量得到显著的抑制和干扰,抑制效果平均达到85%;与野生型对照株相比,5个所测定RNAi转基因株系的穗长、穗粒数、千粒重和穗粒重等籽粒相关性状明显地减小或降低。因此,RNAi介导的基因沉默导致了OsBTF3基因表达水平抑制以及在籽粒性状中的功能缺失;OsBTF3可能是一个调控水稻籽粒相关性状重要的功能基因。 相似文献
992.
Xiaowei Xu Sulin Ren Xiaoxiao Chen Jun Ge Zhenxing Xu Hongying Huang Honglin Sun Yue Gu Tong Zhou Jianqiang Li Hanmei Xu 《Virologica Sinica》2014,(6)
Despite the long availability of a traditional prophylactic vaccine containing the HBV surface antigen(HBsA g) and aluminum adjuvant, nearly 10% of the population remains unable to generate an effective immune response. Previous studies have indicated that hepatitis B virus(HBV) PreS 2-S is abundant in T/B cell epitopes, which induces a stronger immune response than HBsA g, particularly in terms of cytotoxic T lymphocyte(CTL) reaction. In the current study, the HBV PreS 2-S gene encoding an extra26 amino acids(PreS 2 C-terminus) located at the N-terminus of HBsA g was cloned into the pV CH1300 expression vector. Pre S2-S expressed in the methylotrophic yeast, Hansenula polymorpha, was produced at a yield of up to 250 mg/L. Subsequent purification steps involved hydrophobic adsorption to colloidal silica, ion-exchange chromatography and density ultracentrifugation. The final product was obtained with a total yield of ~15% and purity of ~99%. In keeping with previous studies, ~22 nm viruslike particles were detected using electron microscopy. The generated PreS 2-S antigen will be further studied for efficacy and safty in animals. 相似文献
993.
Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an imidazole ring have been reported. These analogues include methyl 1-(2-hydroxyethoxymethyl)imidazole-4, 5-dicarbo-xylate (1), 4,5-dicarbamoyl-1-(2-hydroxyethoxymethyl)imidazole (2), 4,5-dicyano-1-(2-hydroxyethoxymethyl)imidazole (4), Methyl 1-(2-bromoethoxymethyl)imidazole-4,5-dicarboxylate (7), 4,5-dicyano-(2-bromoethoxymethyl)imidazole (8), and Methyl 1-(2-phosphonomethoxyethyl)imidazole (10). Also reported are a few potential prodrugs of the above compounds, including the acetyl derivatives 5 and 6 (of 1 and 4, respectively), and the diethyl phosphonate ester 9 (of 10). In addition, the corresponding benzyl-protected precursors 11 and 12 (of 1 and 4, respectively), along with their common hydrolysis product, 1-(2-benzyloxy-ethoxymethyl)-4,5-imidazoledicarboxylic acid (3), are reported. Another potential prodrug included in the list is 1-(2-acetoxyethyl)-4,5-dicyanoimidazole (15). The compounds were screened for in vitro antiviral activity against a wide variety of herpes and respiratory viruses. The most active compound was the phosphonate analogue 9 which exhibited an anti-measles virus activity with an EC50 of <2.5 microg/mL and an SI value of > 176. 相似文献
994.
995.
Structures of mono-doped fullerenes, C59Xn and C59X(6mn)m (X=Bm, N+, P+, As+, Si), the isoelectronic analogues to C60 and C606m with 60 and 66 pi-electrons, have been investigated at the B3LYP/6-31G* level of density functional theory. On the basis of the computed nucleus independent chemical shifts (NICS) at the cage center and also at the center of individual rings as magnetic criteria, heterofullerenes with 60 pi-electrons are as aromatic as the parent C60, while those with 66 pi-electrons are much less aromatic than C606m. The very distinct endohedral chemical shifts of the 66 pi-electron systems may be useful to identify the heterofullerenes through their endohedral 3He NMR chemical shifts. 相似文献
996.
997.
Jing‐Yuan Chuang Wei‐Hung Yang Hsien‐Te Chen Chun‐Yin Huang Tzu‐Wei Tan Yuh‐Tzy Lin Chin‐Jung Hsu Yi‐Chin Fong Chih‐Hsin Tang 《Journal of cellular physiology》2009,220(2):418-426
CCL5 (previously called RANTES) is in the CC‐chemokine family and plays a crucial role in the migration and metastasis of human cancer cells. On the other hand, the effect of CCL5 is mediated via CCR receptor. RT‐PCR and flow cytometry studies demonstrated CCR5 but not CCR1 and CCR3 mRNA in oral cancer cell lines, especially higher in those with high invasiveness (SCC4) as compared with lower levels in HSC3 cells and SCC9 cells. Stimulation of oral cancer cells with CCL5 directly increased the migration and metalloproteinase‐9 (MMP‐9) production. MMP‐9 small interfering RNA inhibited the CCL5‐induced MMP‐9 expression and thereby significantly inhibited the CCL5‐induced cell migration. Activations of phospholipase C (PLC), protein kinase Cδ (PKCδ), and NF‐κB pathways after CCL5 treatment was demonstrated, and CCL5‐induced expression of MMP‐9 and migration activity was inhibited by the specific inhibitor of PLC, PKCδ, and NF‐κB cascades. In addition, migration‐prone sublines demonstrate that cells with increasing migration ability had more expression of MMP‐9, CCL5, and CCR5. Taken together, these results indicate that CCL5/CCR5 axis enhanced migration of oral cancer cells through the increase of MMP‐9 production. J. Cell. Physiol. 220: 418–426, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
998.
Juxing Chen Jinzhi Wang Kathrin R. Meyers Caroline A. Enns 《Traffic (Copenhagen, Denmark)》2009,10(10):1488-1501
Transferrin receptor 2 (TfR2) is a homologue of transferrin receptor 1 (TfR1) but has distinct functions from TfR1 in iron homeostasis. In keeping with its proposed role in iron sensing, previous studies showed that TfR2 has a short half-life and that holo-Tf stabilizes TfR2 by redirecting it from a degradative pathway to a recycling pathway. In this study, we characterized how the endocytosis, recycling and degradation of TfR2 relates to its function and differs from TfR1. TfR2 endocytosis was adaptor protein-2 (AP-2) dependent. Flow cytometry analysis showed that TfR1 and TfR2 utilized the same endocytic pathway only in the presence of holo-Tf, indicating that holo-Tf alters the interaction of TfR2 with the endocytic machinery. Unlike TfR1, phosphofurin acidic cluster sorting protein 1 (PACS-1) binds to the cytoplasmic domain of TfR2 and data suggest that PACS-1 is involved in the TfR2 recycling. Depletion of TSG101 by siRNA or expression of a dominant negative Vps4 inhibited TfR2 degradation, indicating that TfR2 degradation occurs through a multivesicular body (MVB) pathway. TfR2 degradation is not mediated through ubiquitination on the single lysine (K31) in the cytoplasmic domain or on the amino terminal residue. No ubiquitination of TfR2 by HA-ubiquitin was detected, indicating a lack of direct TfR2 ubiquitination involvement in its degradation. 相似文献
999.
Ji-Fu Wei Xiao-long Wei Qiu-Yu Chen Tian Huang Li-Ya Qiao Wan-Yu Wang Yu-Liang Xiong Shao-Heng He 《Biochimica et Biophysica Acta (BBA)/General Subjects》2006
A novel phospholipase A2 (PLA2) with Asn at its site 49 was purified from the snake venom of Protobothrops mucrosquamatus by using SP-Sephadex C25, Superdex 75, Heparin-Sepharose (FF) and HPLC reverse-phage C18 chromatography and designated as TM-N49. It showed a molecular mass of 13.875 kDa on MALDI-TOF. TM-N49 does not possess enzymatic, hemolytic and hemorrhagic activities. It fails to induce platelet aggregation by itself, and does not inhibit the platelet aggregation induced by ADP. However, it exhibits potent myotoxic activity causing inflammatory cell infiltration, severe myoedema, myonecrosis and myolysis in the gastrocnemius muscles of BALB/c mice. Phylogenetic analysis found that that TM-N49 combined with two phospholipase A2s from Trimeresurus stejnegeri, TsR6 and CTs-R6 cluster into one group. Structural and functional analysis indicated that these phospholipase A2s are distinct from the other subgroups (D49 PLA2, S49 PLA2 and K49 PLA2) and represent a unique subgroup of snake venom group II PLA2, named N49 PLA2 subgroup. 相似文献
1000.
A novel diamino-substituted hypocrellin derived from hypocrellin B (HB) was synthesized by a mild method. The red absorption of the resulting product was significantly enhanced relative to the parent hypocrellins and any other hypocrellin derivatives, and the active oxygen species generating abilities were enhanced distinctly, which will remarkably improve its photodynamic therapy effectiveness. 相似文献