Role of the JAK-STAT pathway in protection of hydrogen peroxide preconditioning against apoptosis induced by oxidative stress in PC12 cells

The aim of this study was to investigate the role of JAK-STAT pathway in the cytoprotection afforded by preconditioning with H₂O₂. It was shown that (1) Preconditioning with 100 μmol/L H₂O₂ can markedly protect PC12 cells against apoptosis and cytotoxicity induced by 300 μmol/L H₂O₂; (2) The expression and tyrosine phosphorylation of JAK2, not JAK1 were rapidly increased at 5 min after H₂O₂ preconditioning; (3) The expression of STAT1 and STAT3 were significantly increased at 15 min after H₂O₂ preconditioning, and the pTyr-STAT1 and pTyr-STAT3 were markedly increased at 60 min after H₂O₂ preconditioning; (4) Pretreatment with the JAK inhibitor AG-490 (10 μmol/L) 20 min before H₂O₂ preconditioning blocked not only the activation of JAK2, STAT1 and STAT3, but also the cytoprotection of H₂O₂ preconditioning against apoptosis and cytotoxicity induced by oxidative stress. These findings suggested that preconditioning with H₂O₂ activated the JAK-STAT pathway that played an important role in the cytoprotection induced by H₂O₂ preconditioning.     

中国人类遗传资源共享利用的标准化研究

中国人类遗传资源平台是国家自然资源科技共享平台的一部分。为规范我国人类遗传资源的收集、整理、整合、保存及共享利用, 在我国相关法律法规的支持下, 作者参照国内外资源整合成功的经验, 对我国人类遗传资源的整理整合及共享利用的标准化进行了研究, 文中简要报道人类遗传资源整理整合、数据库建设及共享利用的标准化研究结果。     

Characterization of a novel C-type lectin-like gene, LSECtin: demonstration of carbohydrate binding and expression in sinusoidal endothelial cells of liver and lymph node

A new C-type lectin-like gene encodes 293 amino acids and maps to chromosome 19p13.3 adjacent to the previously described C-type lectin genes, CD23, dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), and DC-SIGN-related protein (DC-SIGNR). The four genes form a tight cluster in an insert size of 105 kb and have analogous genomic structures. The new C-type lectin-like molecule, designated liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin), is a type II integral membrane protein of approximately 40 kDa in size with a single C-type lectin-like domain at the COOH terminus, closest in homology to DC-SIGNR, DC-SIGN, and CD23. LSECtin mRNA was only expressed in liver and lymph node among 15 human tissues tested, intriguingly neither expressed on hematopoietic cell lines nor on monocyte-derived dendritic cells (DCs). Moreover, LSECtin is expressed predominantly by sinusoidal endothelial cells of human liver and lymph node and co-expressed with DC-SIGNR. LSECtin binds to mannose, GlcNAc, and fucose in a Ca(2+)-dependent manner but not to galactose. Our results indicate that LSECtin is a novel member of a family of proteins comprising CD23, DC-SIGN, and DC-SIGNR and might function in vivo as a lectin receptor.     

Parameters controlling the gene-targeting frequency at the Sphingomonas species rrn site and expression of the methyl parathion hydrolase gene

AIMS: To investigate the key parameters controlling the exogenous methyl parathion hydrolase (MPH) gene mpd-targeting frequency at the ribosomal RNA operon (rrn) site of Sphingomonas species which has a wide range of biotechnological applications. METHODS AND RESULTS: Targeting vectors with different homology lengths and recipient target DNA with different homology identities were used to investigate the parameters controlling the targeting frequency at the Sphingomonas species rrn site. Targeting frequency decreased with the reduction of homology length, and the minimal size for normal homologous recombination was >100 bp. Homologous recombination could succeed even if there were 3-4% mismatches; however, targeting frequency decreased with increasing sequence divergence. The Red recombination system could increase the targeting frequency to some extent. Targeting of the mpd gene to the rrn site did not affect cell viability and resulted in an increase of MPH-specific activity in recombinants. CONCLUSIONS: Targeting frequency was affected by homology length, identity and the Red recombination system. The rrn site is a good target site for the expression of exogenous genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This work is useful as a foundation for a better understanding of recombination events involving homologous sequences and for the improved manipulation of Sphingomonas genes in biotechnological applications.     

Cloning of the flap endonuclease-1 gene in Bombyx mori and identification of an antiapoptotic function

The flap endonuclease-1 (FEN-1) gene is involved in DNA replication and repair, and it maintains genomic stability as well as the accuracy of DNA replication under normal growth conditions. However, FEN-1 also plays an important role in apoptosis and cancer development. We cloned the BmFEN-1 gene from Bombyx mori, which was 1343?bp in length and possessed an 1143?bp ORF (123-1266). It consists of seven introns and eight exons that encode a protein with 380 amino acids that has the typical XPG domain. The N-terminal motif is located at amino acids 95-105, and the proliferating cell nuclear antigen interaction motif is located at amino acids 337-344. RNA interference-mediated reduction of BmFEN-1 expression induced cell cycle arrest in S phase in BmE-SWU1?cells. These results suggest that BmFEN-1 can inhibit apoptosis and promote cell proliferation.     

棕色棉与白色棉缩合单宁单体儿茶素动态变化的比较

以棕色棉ANL-1’和白色棉‘泗棉3号’为材料,利用HPLc检测棉纤维发育过程中儿茶素的动态变化,结果表明：棉种皮中的儿茶素含量高于棉纤维中的,各种儿茶素单体（EGC、C、EC、EGCG、GCG、ECG、cG）的含量在花后30d迅速下降,其中在白色棉纤维中的下降幅度最大;棕色棉和白色棉发育期棉纤维中儿茶素存在很大差异,如棕色棉纤维中有Ec、CG,但在白色棉纤维中却没有发现。初步推断棕色棉与白色棉纤维中缩合单宁结构有较大不同,可能导致棉纤维颜色发生差异。     

A versatile and highly sensitive probe for Hg(II), Pb(II) and Cd(II) detection individually and totally in water samples

The detection of heavy metal ions using enzyme-linked immunosorbent assays (ELISA) has been reported by several research groups. However, highly sensitive and selective detection of total heavy metal ions using ELISA is a major technical limitation. Here we describe the development of a versatile and highly sensitive probe combining goat anti-mice IgG, colloidal gold nanoparticles (AuNPs) and horseradish peroxidase (HRP). We demonstrate the utility of this probe using three kinds of heavy metal complete antigens and three monoclonal antibodies (McAbs) in one ELISA system to establish a high-throughput screening protocol. The procedure was successfully applied to analysis of Hg(II), Pb(II) and Cd(II) individually and totally from different water samples. The sensitivities for the detection of Hg(II), Pb(II) and Cd(II) individually and totally are 27.4, 3.9, 15.8 and 18.2 nM, respectively. And all limit of detection (LODs) are lower than 1.2 nM. The recovery results obtained from the developed technique showed a good correlation (R² = 0.983) with those from ICP-MS. The major advantage of the probe is the versatility and high sensibility. The probe could be potentially used, upon demand, as a sensitive and versatile detector for a broad range of applications.     

The DNA-dependent protein kinase catalytic subunit is phosphorylated in vivo on threonine 3950, a highly conserved amino acid in the protein kinase domain

The protein kinase activity of the DNA-dependent protein kinase (DNA-PK) is required for the repair of DNA double-strand breaks (DSBs) via the process of nonhomologous end joining (NHEJ). However, to date, the only target shown to be functionally relevant for the enzymatic role of DNA-PK in NHEJ is the large catalytic subunit DNA-PKcs itself. In vitro, autophosphorylation of DNA-PKcs induces kinase inactivation and dissociation of DNA-PKcs from the DNA end-binding component Ku70/Ku80. Phosphorylation within the two previously identified clusters of phosphorylation sites does not mediate inactivation of the assembled complex and only partially regulates kinase disassembly, suggesting that additional autophosphorylation sites may be important for DNA-PK function. Here, we show that DNA-PKcs contains a highly conserved amino acid (threonine 3950) in a region similar to the activation loop or t-loop found in the protein kinase domain of members of the typical eukaryotic protein kinase family. We demonstrate that threonine 3950 is an in vitro autophosphorylation site and that this residue, as well as other previously identified sites in the ABCDE cluster, is phosphorylated in vivo in irradiated cells. Moreover, we show that mutation of threonine 3950 to the phosphomimic aspartic acid abrogates V(D)J recombination and leads to radiation sensitivity. Together, these data suggest that threonine 3950 is a functionally important, DNA damage-inducible phosphorylation site and that phosphorylation of this site regulates the activity of DNA-PKcs.     

Cardiovascular responses to intrathecal administration of endomorphins in anesthetized rats

Endomorphins (EMs), the endogenous, potent and selective mu-opioid receptor agonists, have been shown to decrease systemic arterial pressure (SAP) in rats after intravenous (i.v.) administration. In the present study, cardiovascular responses to intrathecal (i.t.) injection of EMs were investigated in urethane-anesthetized rats. It is noteworthy that EMs elicited decreases in SAP and heart rate (HR) in a dose-dependent manner; 10-300nmol/kg were injected intrathecally. Furthermore, these vasodepressor and bradycardic effects were significantly antagonized by naloxone (0.5mg/kg, i.t.). Interestingly, i.t. (5mg/kg) or i.v. (50mg/kg) administrations of N(omega)-nitro-l-arginine methylester (l-NAME) attenuated the vasodepressor and bradycardic effects. Moreover, pretreatment of the rats with muscarinic receptor antagonist atropine (2mg/kg, i.v.) and alpha-adrenoceptor antagonist phentolamine (1mg/kg, i.v.) significantly reduced the vasodepressor effects of EMs. Nevertheless, pretreatment with beta-adrenoceptor antagonist propranolol (2mg/kg, i.v.) could only block the bradycardia effects induced by EMs, but had no significant effects on the hypotension. In summary, all the results suggested that i.t. administration of EMs decreased SAP and HR which were possibly mediated by the activation of opioid receptors in the rat spinal cord. In addition, nitric oxide (NO) release in both the spinal cord and in peripheral tissues might regulate the cardiovascular activities of EMs, and the muscarinic receptor and adrenoceptor played an important role in the regulation of the cardiovascular responses to i.t. administration of EMs.