Mitochondria dynamic is regulated by different proteins, maintaining a balance between fission and fusion. An imbalance towards mitochondrial fission has been associated with tumor cell proliferation. The aim of this study was to analyze whether pectin modifies the viability of human colon cancer cells and the expression of proteins involved in mitochondrial fusion and fission. The human colon carcinoma cell line HT29 cells was growth in 10% fetal bovine serum in the absence and presence of pectin. Pectin reduced HT29 cell viability in a concentration-dependent manner, reaching a plateau at 150~300 μmol/L pectin. The presence of 200 μmol/L pectin reduced the expression of dynamin-related protein-1 and increased expression of the mitochondrial fusion-associated proteins mitofusin-1 and 2. Expression of cyclin B1, a protein involved in G2/M transition, was found decreased in pectin-incubated HT29 cells. Moreover, expression of p53 protein, the amount of p53 in the nucleous and β-galactosidase activity, which are all biomarkers for cellular senescence, were significantly higher in pectin-incubated HT29 cells than in HT29 cells incubated without pectin. Expression of the protein B-cell lymphoma 2 (Bcl-2) homologous antagonist/killer was increased in response to incubation with pectin. However, incubation with pectin did not affect expression of Bcl-2-associated X protein or Bcl-2, or the caspase-3 activity. Overall, we concluded that pectin reduces the viability of human HT29 colon cancer cells, which is accompanied with a shift in the expression of proteins associated with mitochondrial dynamics towards mitochondrial fusion. Moreover, incubation with pectin favors cellular senescence over apoptosis in HT29 cells.

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The pullout tests were carried out to investigate the effect of coating thickness on bond behavior (failure modes, bond strength, bond stress slip curves) between hot rolled plain steel bar (HPB) coated with polymer cement based coating and concrete. The results indicated the failure mode of the specimens is pullout. Suitable coating thickness could enhance the bond strength of steel bar embedded with concrete. By using contact surfaces with cohesive behavior in finite element software, the slip between coated plain steel bar and concrete can be realized. The results of numerical simulation are close to that of experiments, indicating that the model using contact surfaces with cohesive behavior can reasonably predict the results of pullout tests of HPB in concrete.

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