Molecular inhibition mechanisms of cell migration and invasion by coix polysaccharides in A549 NSCLC cells via targeting S100A4.

S100 calcium binding protein A4 (S100A4) promotes extracellular signal transduction, intercellular adhesion, motility and mobility. Different extracts from Coix lachryma-jobi have been used for the treatment of various types of cancer in Asia. In our previous study, the polysaccharide fraction extact, CP1, induced cell apoptosis of non­small cell lung cancer cells. In the current study, CP1 inhibited migration and invasion of A549 cells in a scratch wound healing assay and matrigel invasion assay, respectively. Furthermore, reverse transcription­polymerase chain reaction and western blotting demonstrated that CP1 downregulated the gene and protein expression levels of S100A4. In silico docking analysis demonstrated that polysaccharides may not interfere with dimerization, whereas, the affinity of polysaccharides for an S100A4­NMIIA pocket was margnially greater than at the dimerization sites. Thus, CP1 inhibited A549 cell migration and invasion potentially via downregulation of S100A4, and may also interact with the binding site of S100A4­NMIIA, which indicated that CP1 has potential as an alternative cancer chemotherapeutic by targeting S100A4.

The correlation of the presence and expression levels of cry genes with the insecticidal activities against Plutella xylostella for Bacillus thuringiensis strains.

The use of Bacillus thuringiensis (Bt) strains with high insecticidal activity is essential for the preparation of bioinsecticide. In this study, for 60 Bt strains isolated in Taiwan, their genotypes and the correlation of some cry genes as well as the expression levels of cry1 genes, with their insecticidal activities against Plutella xylostella, were investigated. Pulsed field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) results revealed that the genotypes of these Bt strains are highly diversified. Also, a considerable number of the Bt strains isolated in Taiwan were found to have high insecticidal activities. Since strains that showed individual combined patterns of PFGE and RAPD exhibited distinct insecticidal activities against P. xylostella, thus, these genotypes may be useful for the identification of the new Bt strains and those which have been used in bioinsecticides. In addition, although the presence of cry2Aa1 may have a greater effect on the insecticidal activity of Bt strains in bioassay than other cry genes, only high expression level of cry1 genes plays a key role to determine the insecticidal activity of Bt strains. In conclusion, both RAPD and PFGE are effective in the differentiation of Bt strains. The presence of cry2Aa1 and, especially, the expression level of cry1 genes are useful for the prediction of the insecticidal activities of Bt strains against P. xylostella.

The relative efficacy of different strain combinations of lactic acid bacteria in the reduction of populations of Salmonella enterica Typhimurium in the livers and spleens of mice.

Multispecies probiotics have been reported to be more effective than monostrain probiotics in health promoting for the host. In this study, 12 lactic acid bacteria (LAB) strains were selected based on the level of induction of tumor necrosis factor (TNF)-α in RAW 264.7 macrophage cells. Their adherence to Caco-2 cells and inhibitory effects on Salmonella invasion of Caco-2 cells were compared. Strains with different probiotic properties were then combined and BALB/c mice were fed with LAB strains for 63 days; then the mice were challenged with Salmonella on day 64. For Salmonella-unchallenged mice that received a multistrain combination of LAB strains that have greater TNF-α production in macrophages, greater adherence and inhibit Salmonella invasion of Caco-2 cells to a greater extent, their peritoneal macrophages had greater phagocytic activity. For Salmonella-challenged mice, a significant reduction of Salmonella cells in the livers and spleens of the mice was observed 8 days post challenge. The addition of 12% skim milk powder together with LAB strain combinations significantly enhanced the reduction of Salmonella cells in the mice livers and spleens. In conclusion, we have shown that LAB strain combinations with particular probiotic properties when fed to mice can inhibit Salmonella invasion of the liver and spleen.

Antagonistic activity of spent culture supernatants of lactic acid bacteria against Helicobacter pylori growth and infection in human gastric epithelial AGS cells.

We investigated the bactericidal activity and exclusion effect of 10 strains of lactic acid bacteria (LAB) isolated from different commercial food products and infant feces against Helicobacter pylori (H. pylori) in human gastric epithelial AGS cells. Antagonistic activity of spent culture supernatants (SCS) from LAB (LAB-SCS) was tested, and the content of organic acids in SCS was analyzed with high-performance liquid chromatography (HPLC). In addition, the bactericidal activities of LAB-SCS were estimated by a time-kill assay and by measuring the exclusion effect of LAB-SCS against H. pylori in AGS cells. The results showed that SCS from certain strains with higher concentrations of organic acids dramatically decreased the viability of H. pylori. We also proved that the organic acids could inhibit H. pylori adhesion and invasion of AGS cells. Furthermore, the concentration and speciation of organic acids in SCS after fermentation of LAB are important factors in the inhibition of H. pylori infection. In addition, the in vitro methods used in this study might provide for the rapid screening of potential probiotics with anti-H. pylori activity in the dairy industry.

Viable counts, characteristic evaluation for commercial lactic acid bacteria products.

Eight commercial lactic acid bacteria (LAB) products were assayed for their LAB cell counts, acid and bile tolerance, and adherence to human intestinal epithelium. Results showed that the viable cell densities in liquid products, such as fermented milk samples, were higher than those in the solid products. In two solid products, viable LAB counts were not found indicating the incorrect labeling on the package. With a simulated human gastrointestinal digestion system, LAB strains from different commercial products were found to have different acid and bile tolerance. Twenty five LAB isolates from five commercial products were assayed for their antagonistic activities against bacterial pathogens, such as Staphylococcus aureus, Escherichia coli including enterotoxigenic strain, and Salmonella typhimurium. The spent culture supernatant (SCS) from some LAB isolates significantly inhibited the growth of these indicator bacteria. Among these 25 isolates, only five from one commercial product exhibited weak adherence to the human intestinal epithelial cells (Int-407). The rest showed no adherence at all. In conclusion, only few commercial LAB products meet the basic requirements for probiotic functions.