Enhanced Production of Active Ecumicin Component with Higher Antituberculosis Activity by the Rare Actinomycete sp. MJM5123 Using a Novel Promoter-Engineering Strategy.

Ecumicins are potent antituberculosis natural compounds produced by the rare actinomycete sp. MJM5123. Here, we report an efficient genetic manipulation platform of this rare actinomycete.

[Remediation performance and mechanism of aquatic plants for iron polluted water].

To solve the yellow colorization in water caused by iron ion, we evaluated the remediation performances of six aquatic plant species (Hygroryza aristata, Myriophyllum verticillatum, Hydrocotyle verticillata, Jussiaea stipulacea, Pistia stratiotes and Rotala rotundifolia) using hydroponic experiment. Effects of iron concentration, pH, plant biomass on iron removal were investigated, and the intensification of removing iron incurred by aeration was also discussed. Results showed that all the examined plant species could improve both divalent iron and total iron removal, but with significant difference in their performance.

[Relationship between terminal sialyl and fucosyl residues of glycans on cell surface and cell biological behaviors].

The relationship between the structures of glycans on the surface of H7721 cells, a human hepatocarcinoma cell line, and the cell behaviors was studied by using neuraminidase and alpha-L-fucosidase to remove the terminal sialyl or fucosyl residues of surface glycans respectively. The cell adhesion to fibronectin (Fn), laminin (Ln) and human umbilical vein epithelial cell (HUVEC), as well as cell chemotactic migration and invasion were selected as the parameters of the cell behaviors. It was found that sialyl residue was not essential for the cell adhesion to Fn, but was important in the cell adhesion to Ln and chemotactic cell invasion, and very crucial in the cell adhesion to HUVEC and chemotactic migration.

Relations of the type and branch of surface N-glycans to cell adhesion, migration and integrin expressions.

The relations between the structure of cell surface N-glycans to cell behaviors were studied in H7721 human hepatocarcinoma cell line, which predominantly expressed complex-type N-glycans on the surface. 1-Deoxymannojirimycin (DMJ) and swaisonine (SW), the specific inhibitor of Golgi alpha-mannosidase II or I, were selected to block the processing of N-glycans at the steps of high mannose and hybrid type respectively. All-trans retinoic acid (ATRA) and antisense cDNA of N-acetylglucosaminyltransferase-V (GnT-V) were used to suppress the expression of GnT-V and decreased the GlcNAc beta1,6-branching or tri-/tetra-antennary structure of surface N-glycans.

Effect of N-acetylglucosaminyltransferase V on the expressions of other glycosyltransferases.

Transfection of sense cDNA of N-acetylglucosaminyltransferase V (GnTV) into H7721 human hepatocellular carcinoma cells resulted in the decreased expression of surface sialyl Lewis X (SLe(x)), a sialylated fucose-containing antigen. The enzymatic mechanisms were speculated to be the concomitantly decreased expression of alpha1,3-fucosyltransferase (FucT)-III, -VI, -VII and the branching enzyme of O-glycans, core 2-beta1,6-N-acetylglucosaminyltransferase (C2GnT)-I, -II. These two glycosyltransferase families were suggested to be the key enzymes in the synthesis of SLe(x).

Forskolin up-regulates metastasis-related phenotypes and molecules via protein kinase B, but not PI-3K, in H7721 human hepato-carcinoma cell line.

Forskolin (FSK) is known as an up-regulator of intracellular cAMP and inhibitor of cancer growth and metastasis. The effects of FSK on the metastasis potential and its mechanisms were studied using a human hepatocarcinoma cell line, H7721. It was found that FSK stimulated cell growth, increased cAMP in the cells, and enhanced the metastasis-related phenotypes, including adhesion to laminin (Ln) and human umbilical vein epithelial cells (HUVEC), chemotactic migration and invasion.

Regulation on the expression and N-glycosylation of integrins by N-acetylglucosaminyltransferase V.

The expressions of integrin alpha5, beta1, and alpha6 were studied in H7721 cells by means of flow cytometric and RT-PCR method after transfected with sense and antisense cDNA of N-acetylglucosaminyltransferase V (GnT-V). The transfected cells were characterized by Northern blot. It was found that the order of expression from high to low was beta1>alpha5>alpha6.

Insulin/protein kinase B signalling pathway upregulates metastasis-related phenotypes and molecules in H7721 human hepatocarcinoma cell line.

The effect of insulin on cancer metastatic potential was studied in a human hepatocarcinoma cell line, H7721. Cell adhesion to human umbilical vein endothelial cells (HUVECs) and laminin as well as chemotactic cell migration and invasion were selected as the indices of metastasis-related phenotypes for assessment of metastatic potential ex vivo. The results indicated that insulin enhanced all of these metastasis-related phenotypes.

Alteration in the expression of early stage processing enzymes of N-glycan during myeloid and monocytoid differentiation of HL-60 cells.

The expressions of the enzymes participating in the early stage of N-glycan processing, Golgi alpha-Mase-I, alpha-Mase-II and GnT-I, GnT-II, were studied before and after HL-60 cells were differentiated to myelocytes or monocytes induced by ATRA or PMA, respectively. It was found that alpha-Mase-I activity and GnT-I mRNA were decreased by both ATRA and PMA, while alpha-Mase-II and GnT-II were altered insignificantly. The down-regulation of alpha-Mase-I and GnT-I was cell specific, since ATRA up-regulated alpha-Mase-I and GnT-I in the H7721 hepatocarcinoma cell line.

Regulation of Phospholipase D Activity in Human Hepatocacinoma Cells by Protein Kinases and D-sphingosine.

The effects of some inhibitors of protein kinase C(PKC) and tyrosine protein kinase(TPK)as well as the antibodies to PKC isotypes on the activity of phosphatidylcholine-specific phospholipase D(PLD)in 7721 human hepatocarcinoma cells were determined in order to study the regulation of PKC and TPK on PLD in these cells. It was found that all of the four inhibitors of PKC (chelerythrine, H-7, calphostin C and stausporine) and two inhibitors of TPK (tyrphostin 46 and genistein) partially inhibited the basal activity of PLD. Among them, the inhibition rates of staurosporine and calphostin C were the highest.