A Ran-independent pathway for export of spliced mRNA

All major nuclear export pathways so far examined follow a general paradigm. Specifically, a complex is formed in the nucleus, containing the export cargo, a member of the importin-beta family of transporters and RanGTP. This complex is translocated across the nuclear pore to the cytoplasm, where hydrolysis of the GTP on Ran is stimulated by the GTPase-activating protein RanGAP. The activity of RanGAP is increased by RanBP1, which also promotes disassembly of RanGTP-cargo-transporter complexes. Here we investigate the role of RanGTP in the export of mRNAs generated by splicing. We show that nuclear injection of a Ran mutant (RanT24N) or the normally cytoplasmic RanGAP potently inhibits the export of both tRNA and U1 snRNA, but not of spliced mRNAs. Moreover, nuclear injection of RanGAP together with RanBP1 blocks tRNA export but does not affect mRNA export. These and other data indicate that export of spliced mRNA is the first major cellular transport pathway that is independent of the export co-factor Ran.     

Legal Professionals' Knowledge of Eyewitness Testimony in China: A Cross-Sectional Survey

Purpose

To examine legal professionals’ knowledge of a wide range of factors that affect eyewitness accuracy in China.

Methods

A total of 812 participants, including 210 judges, 244 prosecutors, 202 police officers, and 156 defense attorneys, were asked to respond to 12 statements about eyewitness testimony and 3 basic demographic questions (i.e., gender, age, and prior experience).

Results

Although the judges and the defense attorneys had a somewhat higher number of correct responses than the other two groups, all groups showed limited knowledge of eyewitness testimony. In addition, the participants’ responses to only four items (i.e., weapon focus, attitude and expectations, child suggestibility, and the impact of stress) were roughly unanimous within the four legal professional groups. Legal professionals’ gender showed no significant correlations with their knowledge of eyewitness testimony. Prior experiences were significantly and negatively correlated with the item on the knowledge of forgetting curve among judges but positively correlated with two items (i.e., attitudes and exposure time) among defense attorneys and with 4 statements (i.e., the knowledge of attitudes and expectations, impact of stress, child witness accuracy, and exposure time) among prosecutors.

Conclusions

The findings suggest that knowledge of the factors that influence eyewitness accuracy must be more effectively communicated to legal professionals in the future.     

褐飞虱翊型分化遗传规律的研究

以褐飞虱Nilaparvata lugens (Stal)长翅型(macroptery,简称M)、短翅型(brachyptery,简称B)的遗传纯系为实验材料,进行亲本、稻株生育期、虫口密度三因子交互实验。结果表明：(1)在环境条件(指稻株生育期、虫口密度等)一致时,B♀×B♂、B♀×M♂、M♀×B♂、M♀×M♂四种亲本组合的F1代短翅型成虫百分率分别为：98%、92%、64%、29%,各亲本组合间差异极显著;(2)亲本相同时,将F1代褐飞虱初孵若虫多头词养(多于l0头/株)在黄熟期稻株上,其长翅型雌、雄成虫百分数均高于灌浆期稻株上;(3)单头饲养实验中发现,不论亲本组合、稻株生育期如何,雌虫绝大多数分化为短翅型,而雄虫则几乎全为长翅型。这表明褐飞虱的翅型分化遗传由一个受多种因子影响的调控体系决定,且调控作用与性别有关。     

Isolation and characterization of a Pti1 homologue from soybean

A full-length gene GmPti1 was identified from soybean in an EST sequencing project by its homology to tomato Pti1. It encoded a protein of 366 amino acids. RT-PCR analysis showed that the GmPti1 expression was induced by salicylic acid and wounding. The deduced amino acid sequence had a Ser/Thr/Tyr kinase domain. GmPti1 protein was expressed in E. coli as an MBP fusion, purified by amylose resin and examined for its autophosphorylation ability. The phosphorylation assay in vitro showed that GmPti1 had kinase activity in the presence of Mn2+. These results demonstrated that GmPti1 represented a new Pti1-like gene, unlike the two published genes sPti1a and sPti1b, which encoding proteins had no autophosphorylation ability.     

Mechanism of bFGF-binding Peptide Reversing Adriamycin Resistance in Human Gastric Cancer Cells

Development of drug resistance is a challenging problem in cancer chemotherapy. It has been shown that basic fibroblast growth factor (bFGF) plays an important role in an epigenetic mechanism of drug resistance. We have isolated a bFGF binding peptide P7 with inhibitory activity against bFGF-induced proliferation of human gastric cancer cells by screening a phage display library. In this study, we found that P7 peptide also has efficacy of reversing bFGF-induced resistance to Adriamycin (ADM) in human gastric cancer cells. Further investigations with SGC-7901 cells revealed that inhibition of Akt activation triggered by bFGF, and reversal of bFGF-induced up-regulation of Bcl-2 and XIAP and down-regulation of Bax, contribute to P7 peptide counteracting the anti-apoptotic effect of bFGF, and further reversing bFGF-induced resistance to ADM. The results suggested that the bFGF-binding peptide may have therapeutic potential of drug resistance in gastric cancer.     

Comparative study of apoptosis-related gene loci in human, mouse and rat genomes

Many genes are involved in mammalian cell apoptosis pathway. These apoptosis genes often contain characteristic functional domains, and can be classified into at least 15 functional groups, according to previous reports. Using an integrated bioinformatics platform for motif or domain search from three public mammalian proteomes (International Protein Index database for human, mouse, and rat), we systematically cataloged all of the proteins involved in mammalian apoptosis pathway. By localizing those proteins onto the genomes, we obtained a gene locus centric apoptosis gene catalog for human, mouse and rat.Further phylogenetic analysis showed that most of the apoptosis related gene loci are conserved among these three mammals. Interestingly, about one-third of apoptosis gene loci form gene clusters on mammal chromosomes, and exist in the three species, which indicated that mammalian apoptosis gene orders are also conserved. In addition, some tandem duplicated gene loci were revealed by comparing gene loci clusters in the three species. All data produced in this work were stored in a relational database and may be viewed at http://pcas.cbi.pku.edu.cn/database/apd.php.     

A Putative Plasma Membrane Cation/proton Antiporter from Soybean Confers Salt Tolerance in <Emphasis Type="Italic">Arabidopsis</Emphasis>

Cation transport is thought to be an important process for ion homeostasis in plant cells. Here, we report that a soybean putative cation/proton antiporter GmCAX1 may be a mediator of this process. GmCAX1 is expressed in all tissues of the soybean plants but at a lower level in roots. Its expression was induced by PEG, ABA, Ca²⁺, Na⁺ and Li⁺ treatments. The GmCAX1-GFP fusion protein was mainly localized in plasma membrane of the transgenic Arabidopsis plant cells and onion epidermal cells. Transgenic Arabidopsis plants overexpressing GmCAX1 accumulated less Na⁺, K⁺, and Li⁺, and were more tolerant to elevated Li⁺ and Na⁺ levels during germination when compared with the controls. These results suggest that GmCAX1 may function as an antiporter for Na⁺, K⁺ and Li⁺. Modulation of this antiporter may be beneficial for regulation of ion homeostasis and thus plant salt tolerance.     

双波长分光光度法测定肝素钠效价

本文介绍了在室温条件下,以天青作显色剂,用双波长分光光度法测定肝素钠的效价。本法快速准确,测定浓度0—20u/ml,相对误差在±4％以内,标准偏差0.19,变异系数2.5‰,与羊血浆法测定结果相差±4u/ml以内。     

Remodeling of the vascular tunica media is essential for development of collateral vessels in the canine heart

Previous studies have shown that neointima formation and adventitial remodeling play an important role in the enlargement of collateral vessels (CVs) during coronary arteriogenesis in the dog heart. In this study, we investigated the importance of remodeling of the tunica media in the same model. Basal membrane (BM), contractile and cytoskeletal components of smooth muscle cells (SMCs) were studied in growth of coronary CVs induced by chronic occlusion of the left circumflex (LCX) coronary artery by routine histology, electron microscopy (EM), and immunoconfocal microscopy using antibodies against α-smooth actin (α-SM actin), calponin, desmin, and laminin. In addition, matrix metalloproteinase-2 (MMP-2) and tissue inhibitor-1 of matrix metalloproteinase (TIMP-1) were investigated. The data showed that (1) in normal small arteries (NVs) laminin formed a network in which SMCs were encaged;α-SM actin, calponin and desmin were evenly expressed in SMCs; (2) in early (2 weeks) growing CVs the laminin network was disrupted, desmin was significantly reduced in SMCs, but α-SM actin and calponin still highly expressed; (3) in actively (6 weeks) growing CVs laminin was still weak in the tunica media (TM), but without network-like structure. Desmin was further reduced in SMCs of TM, whereas α-SM actin and calponin showed little changes, although they were significantly decreased in intimal SMCs; (4) in mature CVs, the network-like structure was re-formed, and α-SM actin, calponin, and desmin were all similar to that in normal vessels; (5) histology for BM confirmed laminin staining; (6) EM revealed that in NVs the SMCs contained abundant contractile filaments and were surrounded by a layer of BM whereas in growing CVs, BM structure was not observed, but the SMCs in the media still contained many myofilaments; (7) MMP-2 was highly expressed in the media of early growing vessels, but decreased in TM of actively growing vessels where TIMP-1 expression was high. In conclusion, our data revealed features of TM of growing CVs. Disruption and degradation of BM facilitate SMC proliferation, and together with reduction of desmin and fragmentation of the internal elastic lamina enable the vascular wall to expand and enlarge when blood pressure and shear stress increase. MMP2 may be an important player in regulating SMC phenotype, proliferation, migration and maintaining integrity of the vascular wall through governing proteolysis during arteriogenesis. (Mol Cell Biochem 264: 201–210, 2004)