Biotype status and distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) in Shandong province of China based on mitochondrial DNA markers

Bemisia tabaci has caused significant crop losses in China during the last decade. Recent research has shown that two potentially invasive variants, biotypes B and Q, have been found in several regions of China. Our objective was to determine the biotype status and the distribution of B. tabaci in Shandong province, an important agricultural region of China. Based on mitochondrial DNA markers, both biotypes B and Q were detected, with B being the predominant biotype. The results indicate that the more recently introduced biotype Q has not only been located in China but also has established and spread in some regions.     

Hemopoietic cell expression of the chemokine decoy receptor D6 is dynamic and regulated by GATA1

D6 scavenges inflammatory chemokines and is essential for the regulation of inflammatory and immune responses. Mechanisms explaining the cellular basis for D6 function have been based on D6 expression by lymphatic endothelial cells. In this study, we demonstrate that functional D6 is also expressed by murine and human hemopoietic cells and that this expression can be regulated by pro- and anti-inflammatory agents. D6 expression was highest in B cells and dendritic cells (DCs). In myeloid cells, LPS down-regulated expression, while TGF-beta up-regulated expression. Activation of T cells with anti-CD3 and soluble CD28 up-regulated mRNA expression 20-fold, while maturation of human macrophage and megakaryocyte precursors also up-regulated D6 expression. Competition assays demonstrated that chemokine uptake was D6 dependent in human leukocytes, whereas mouse D6-null cells failed to uptake and clear inflammatory chemokines. Furthermore, we present evidence indicating that D6 expression is GATA1 dependent, thus explaining D6 expression in myeloid progenitor cells, mast cells, megakaryocytes, and DCs. We propose a model for D6 function in which leukocytes, within inflamed sites, activate D6 expression and thus trigger resolution of inflammatory responses. Our data on D6 expression by circulating DCs and B cells also suggest alternative roles for D6, perhaps in the coordination of innate and adaptive immune responses. These data therefore alter our models of in vivo D6 function and suggest possible discrete, and novel, roles for D6 on lymphatic endothelial cells and leukocytes.     

Regulation of alternative splicing of Bcl-x by IL-6, GM-CSF and TPA

The splicing of many alternative exons in the precursor messenger RNA (pre-mRNA) is regulated by extracellular factors but the underlying molecular bases remain unclear. Here we report the differential regulation of Bcl-x pre-mRNA splicing by extracellular factors and their distinct requirements for pre-mRNA elements. In K562 leukemia cells, treatment with interleukin-6 (IL-6) or granulocyte-macrophage colony stimulating factor (GM-CSF) reduced the proportion of the Bcl-xL variant mRNA while treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) had no effect. In U251 glioma cells, however, TPA efficiently increased the Bcl-xL level. These regulations were also seen for a transfected splicing reporter mini-gene. Further analyses of deletion mutants indicate that nucleotides 1-176 of the downstream intron are required for the IL-6 effect, whereas additional nucleotides 177-284 are essential for the GM-CSF effect. As for the TPA effect, only nucleotides 1-76 are required in the downstream intron. Thus, IL-6, GM-CSF and TPA differentially regulate Bcl-x splicing and require specific intronic pre-mRNA sequences for their respective effects.     

Moderate mechanical stimulation rescues degenerative annulus fibrosus by suppressing caveolin-1 mediated pro-inflammatory signaling pathway

Mechanical loading can induce or antagonize the extracellular matrix (ECM) synthesis, proliferation, migration, and inflammatory responses of annulus fibrosus cells (AFCs), depending on the loading mode and level. Caveolin-1 (Cav1), the core protein of caveolae, plays an important role in cellular mechanotransduction and inflammatory responses. In the present study, we presented that AFCs demonstrated different behaviors when subjected to cyclic tensile strain (CTS) for 24 h at a magnitude of 0%, 2%, 5% and 12%, respectively. It was found that 5% CTS had positive effects on cell proliferation, migration and anabolism, while 12% CTS had the opposite effects. Besides, cells exposed to interleukin-1β stimulus exhibited an increase expression in inflammatory genes, and the expression of these genes decreased after exposure to moderate mechanical loading with 5% CTS. In addition, 5% CTS decreased the level of Cav1 and integrin β1 and exhibited anti-inflammatory effects. Moreover, the expression of integrin β1 and p-p65 increased in AFCs transfected with Cav1 plasmids. In vivo results revealed that moderate mechanical stimulation could recover the water content and morphology of the discs. In conclusion, moderate mechanical stimulation restrained Cav1-mediated signaling pathway and exhibited anti-inflammatory effects on AFCs. Together with in vivo results, this study expounds the underlying molecular mechanisms on the effect of moderate mechanical stimulation on intervertebral discs (IVDs) and may provide a new therapeutic strategy for the treatment of IVD degeneration.     

Apoptotic effects of over-expressed estrogen receptor-beta on LoVo colon cancer cell is mediated by p53 signalings in a ligand-dependent manner

Epidemiologic studies reported that the prevalence of hereditary non-polyposis colon cancer (HNPCC) in male is about 1.5-fold higher than that in female. Decreases in circulatory estradiol (E2) have been reported to downregulate the expression of E2 receptor (ER) and significantly increase the risk of colorectal cancer. Patients that received E2 replacement therapy were found to have a reduction in the incidence of colon adenoma and carcinoma. Furthermore, significant decreases in the expression of ER have been found in colorectal cancer specimens. These data strongly suggest the protective roles of E2 and ER against colorectal cancer. However, the mechanisms remain unexplored. LoVo cells were transient transfected to overexpress ER-beta, DNA fragmentation and caspase activity assay were performed to evaluate apoptotic effects. Western blotting was used to evaluate protein levels, and luciferase activity assay to measure the TNF-alpha promoter activity. Our data clearly demonstrated that E2 and ER-beta alone could upregulate p21 and p27 proteins, which further activate caspase-8 and caspase-9 to induce apoptosis in LoVo cell, and the ER-beta. effects were enhanced by E2. However, overexpressed ER-beta did not influence the expression and promoter activity of TNF-alpha. In addition, E2 and overexpressed ER-beta downregulated the beta-catenin proteins which cause the downregulation of its target genes, cyclin D1 and Rb, to inhibit the cell cycle and cell proliferation. The results indicate that overexpressed ER-beta may induce LoVo cell apoptosis and anti-proliferation by increasing p53 signaling in a ligand-dependent manner, and without hTNF-alpha involvement. Efforts aiming at enhancing ER-beta expression and/or activity may prove to be an attractive alternative therapy against colorectal cancer.     

Ammonia-induced structural changes of the oxygen-evolving complex in photosystem II as revealed by light-induced FTIR difference spectroscopy

Light-induced Fourier transform infrared difference spectroscopy has been applied to studies of ammonia effects on the oxygen-evolving complex (OEC) of photosystem II (PSII). We found that NH(3) induced characteristic spectral changes in the region of the symmetric carboxylate stretching modes (1450-1300 cm(-1)) of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra of PSII. The S(2) state carboxylate mode at 1365 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectrum of the controlled samples was very likely upshifted to 1379 cm(-1) in that of NH(3)-treated samples; however, the frequency of the corresponding S(1) carboxylate mode at 1402 cm(-1) in the same spectrum was not significantly affected. These two carboxylate modes have been assigned to a Mn-ligating carboxylate whose coordination mode changes from bridging or chelating to unidentate ligation during the S(1) to S(2) transition [Noguchi, T., Ono, T., and Inoue, Y. (1995) Biochim. Biophys. Acta 1228, 189-200; Kimura, Y., and Ono, T.-A. (2001) Biochemistry 40, 14061-14068]. Therefore, our results show that NH(3) induced significant structural changes of the OEC in the S(2) state. In addition, our results also indicated that the NH(3)-induced spectral changes of the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the temperature of the FTIR measurement. Among the temperatures we measured, the strongest effect was seen at 250 K, a lesser effect was seen at 225 K, and little or no effect was seen at 200 K. Furthermore, our results also showed that the NH(3) effects on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the concentrations of NH(4)Cl. The NH(3)-induced upshift of the 1365 cm(-1) mode is apparent at 5 mM NH(4)Cl and is completely saturated at 100 mM NH(4)Cl concentration. Finally, we found that CH(3)NH(2) has a small but clear effect on the spectral change of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum of PSII. The effects of amines on the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra (NH(3) > CH(3)NH(2) > AEPD and Tris) are inverse proportional to their size (Tris approximately AEPD > CH(3)NH(2) > NH(3)). Therefore, our results showed that the effects of amines on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are sterically selective for small amines. On the basis of the correlations between the conditions (dependences on the excitation temperature and NH(3) concentration and the steric requirement for the amine effects) that give rise to the NH(3)-induced upshift of the 1365 cm(-)(1) mode in the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII and the conditions that give rise to the altered S(2) state multiline EPR signal, we propose that the NH(3)-induced upshift of the 1365 cm(-1) mode is caused by the binding of NH(3) to the site on the Mn cluster that gives rise to the altered S(2) state multiline EPR signal. In addition, we found no significant NH(3)-induced change in the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum at 200 K. Under this condition, the OEC gives rise to the NH(3)-stabilized g = 4.1 EPR signal and a suppressed g = 2 multiline EPR signal. Our results suggest that the structural difference of the OEC between the normal g = 2 multiline form and the NH(3)-stabilized g = 4.1 form is small.     

Membrane topology of mouse stearoyl-CoA desaturase 1

Stearoyl-CoA desaturase (SCD) is an integral membrane protein anchored in the endoplasmic reticulum. It catalyzes the biosynthesis of monounsaturated fatty acids that are required for the synthesis of triglycerides, cholesteryl esters, and phospholipids. Four mouse isoforms of SCD (SCD1-4) and two human isoforms have been characterized. In the current study, we characterize the topology of the mouse SCD1 isoform. Hydropathy analysis of the 355-amino acid mouse SCD1 protein predicts that the protein contains four transmembrane domains (TMDs) and three loops connecting the membrane-spanning domains. To define the topology of the protein, recombinant SCD1 constructs containing epitope tags were transiently expressed in HeLa cells and analyzed by indirect immunofluorescence and cysteine derivatization. Our data provide evidence that the N and C termini of SCD1 are oriented toward the cytosol with four transmembrane domains separated by two very short hydrophilic loops in the ER lumen and one large hydrophilic loop in the cytosol. In addition, based on the previous observation that SCD is a thiol enzyme, we sought to investigate whether the cysteine residues were essential for enzyme activity through mutagenesis studies, and our data suggest that the cysteines in SCD are not catalytically essential.     

Role of nuclear chromogranin B in inositol 1,4,5-trisphosphate-mediated nuclear Ca2+ mobilization

Recently, secretory granule Ca(2+) storage protein chromogranin B (CGB) was shown to be present in the nucleoplasm proper in a complex structure that consists of the inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca(2+) channels and the phospholipids. Further, the amounts of IP(3)Rs present in the nucleus of bovine chromaffin cells were shown to be comparable to that of the endoplasmic reticulum. Therefore, we investigated here the potential contribution of nuclear CGB on the IP(3)-dependent Ca(2+) mobilization in the nucleus, using both neuroendocrine PC12 and nonneuroendocrine NIH3T3 cells. Chromogranin A (CGA) expression in the NIH3T3 cells, which do not contain intrinsic chromogranins, increased the IP(3)-induced Ca(2+) releases in the nucleus by 45%, while CGB expression in the same cells increased the IP(3)-induced Ca(2+) releases in the nucleus by 80%. Microinjection of IP(3) into the nucleus of CGB-expressing NIH3T3 cells increased the IP(3)-dependent nuclear Ca(2+) mobilization approximately 3-fold, whereas in CGA-expressing cells it remained the same as that of control cells. In contrast, inhibition of CGA expression in PC12 cells by siRNA treatment decreased the IP(3)-induced Ca(2+) releases in the nucleus by 17%, while inhibition of CGB expression decreased the IP(3)-induced Ca(2+) releases in the nucleus by 55%. Microinjection of IP(3) into the nucleus of siCGB-treated PC12 cells decreased the IP(3)-dependent nuclear Ca(2+) mobilization by approximately 75%, whereas in siCGA-treated cells it remained the same as that of control cells. Given the presence of CGB in the nucleus, these results further highlight the critical contribution of nuclear CGB in the IP(3)-induced Ca(2+) release in the nucleus.     

离乳大鼠假性性早熟模型的建立及对雌活性物质的应答

以雌激素含量明确的避孕药物作诱导剂观察了其对离乳Wistsar大鼠性成熟的影响,结果显示在给予避孕药后体重、乳腺、阴门、阴道上皮细胞、卵巢、子宫均发生类似人体假性性早熟变化,而肾上腺、脑垂体、甲状腺等与对照组比较均未见明显差异。