Deoxymikanolide adversely altered physiology and ultrastructure of Ralstonia solanacearum.

Deoxymikanolide (DEO) was isolated from Mikania micrantha Bunge and identified as a novel antibacterial compound previously. However, the mode of antimicrobial mechanism of DEO was not clear but hypothesized to affect the morphology and physiology of Ralstonia solanacearum cells. In this study, we confirmed our hypothesis via transmission electron microscopy (TEM) observation and comprehensive physiological analyses, including electric conductivity, glycan and phosphorus metabolism, activities of antioxidant enzymes (catalase, peroxidase, and superoxide dismutase), intrabacterial reactive oxygen species (ROS), and malondialdehyde (MDA) levels. We found that glycan and phosphorus metabolism, electric conductivity, intracellular ROS and MDA levels of R. solanacearum cells were significantly increased, while the activities of three antioxidant enzymes were significantly inhibited by DEO treatment. Moreover, TEM analysis showed that DEO treatment led to an early-stage of cell shrinkage, intermediate-stages of cytoplasmic damage, and a final-stage of cell disruption. Altogether, our data presented here indicate that DEO could adversely affect the physiology and morphology of R. solanacearum cells and be treated as an alternative antibacterial treatment in the future.

Label-free quantitative proteomics analysis of Humulus scandens (Lour.) Merr. leaves treated by an odor compound of Periploca sepium Bunge.

The odor compound from Periploca sepium Bunge, 2-hydroxy-4-methoxy-benzaldehyde (HMB), is an allelochemical agent and is one of the least investigated isomers of vanillin. In this study, we used label-free quantitative proteomics analysis technology to investigate the effect of HMB on the protein expression of Humulus scandens (Lour.) Merr. leaves in July 2019 on Guiyang. A total of 269 proteins of 624 identified proteins were differentially expressed, among which 21.18% of the proteins were up-regulated and 32.71% down-regulated. These proteins were classified into 11 cell components and more than 20% of differentially expressed proteins were located in cell membrane and chloroplast. Functional classification analysis showed that 12 molecular functions were altered upon HMB treatment, and the ratio of catalytic activity was the highest (19.53%). At least 12 biological functions were affected, which involved small molecule metabolic processes, organic substance metabolic processes, gene expression, and photosynthesis. Our data provide resources and insights into the biochemical mechanism by which HMB kills weeds.

Lily extracts inhibit the proliferation of gastric carcinoma SGC-7901 cells by affecting cell cycle progression and apoptosis via the upregulation of caspase-3 and Fas proteins, and the downregulation of FasL protein.

The present study aimed to investigate the effect of alkaloids and carbinol extracts from lily on the proliferation of SGC-7901 cells, as well as the underlying mechanism. SGC-7901 cells were incubated with different concentrations of alkaloid or carbinol extracts for 24, 48 or 72 h. MTT assays were used to measure the inhibition rate of SGC-7901 cell proliferation. Inverted phase contrast and fluorescence microscopy was used to observe morphological changes of SGC-7901 cells. Flow cytometry was employed to detect cell cycle progression and apoptosis rates of SGC-7901 cells. Western blotting was performed to measure the expression of caspase-3, Fas and Fas ligand (FasL) proteins in SGC-7901 cells. The inhibition rate of SGC-7901 cell proliferation was significantly enhanced with increasing drug concentrations and time elapsed. Treatment with alkaloid or carbinol extracts deteriorated the morphology of SGC-7901 cells in a dose-dependent manner. Alkaloid and carbinol extracts arrested SGC-7901 cells in the G2/M phase, and induced apoptosis in a dose-dependent manner. Alkaloid and carbinol extracts enhanced caspase-3, and Fas expression, but reduced FasL expression in SGC-7901 cells. The present study demonstrated that alkaloids and carbinol extracts from lily inhibited the proliferation of gastric carcinoma SGC-7901 cells by arresting cells in the G2/M phase. The upregulation of caspase-3 and Fas proteins, and the downregulation of FasL protein may be an important mechanism for the induction of SGC-7901 cell apoptosis.

Effects of salinomycin and 17­AAG on proliferation of human gastric cancer cells in vitro.

The aim of the present study was to investigate the effects and mechanisms of 17­AAG combined with salinomycin treatment on proliferation and apoptosis of the SGC­7901 gastric cancer cell line. An MTT assay was used to detect the proliferation of SGC­7901 cells. Morphological alterations of cells were observed under inverted phase­contrast and fluorescence microscopes. Cell cycle and apoptosis were assessed by flow cytometry analysis. The protein expression of nuclear factor (NF)­κB p65 and Fas­ligand (L) were evaluated by immunocytochemistry. Salinomycin with a concentration range of 1­32 µmol/l was demonstrated to inhibit growth of SGC­7901 cells effectively, affect the morphology and apoptosis rate of cells, and arrest SGC­7901 cells in S phase. Furthermore, salinomycin significantly increased the protein expression of Fas­L and decreased the protein expression of NF­κB p65. The alterations in SGC­7901 cells co­treated with salinomycin and 17­AAG were more significant compared with cells treated with one drug only. In conclusion, the individual use of salinomycin and combined use with 17­AAG may significantly inhibit SGC­7901 gastric cancer cell proliferation and induce cell apoptosis. The potential mechanisms may be associated with upregulation of Fas­L and downregulation of NF­κB. These results provide a basis for the potential use of salinomycin in gastric cancer treatment.

An in vitro study on the effects of the combination of salinomycin with cisplatin on human gastric cancer cells.

The present study aimed to investigate the anticancer effects of cisplatin (DDP) combined with salinomycin (SAL) on the gastric cancer cell line SGC­7901, as well as to explore the mechanisms underlying their actions. An MTT assay was used to evaluate the inhibitory effects of SAL, DDP and their combination on gastric cancer cell proliferation. Morphological alterations of cancer cells following treatment were observed under an inverted phase­contrast microscope and a fluorescence microscope. Cell cycle progression and apoptosis were analyzed using flow cytometry. The expression of nuclear factor (NF)­κB p65 and Fas protein ligand (L) in cancer cells was assessed using immunocytochemistry. The present results demonstrated that the combination of SAL and DDP significantly inhibited the proliferation (P<0.05) and altered the morphological characteristics of SGC­7901 cells, thus suggesting that SAL may enhance the susceptibility of gastric cancer cells to DDP. In addition, treatment with a combination of SAL and DDP resulted in S phase­arrest and increased the apoptotic rate of SGC­7901 cells. Furthermore, marked FasL upregulation and NF­κB p65 downregulation were observed in cancer cells treated with the combination of SAL and DDP. The results of the present study demonstrated that the combination of SAL and DDP induced the apoptosis of human gastric cancer cells, and suggested that the underlying mechanism may involve the upregulation of FasL and downregulation of NF­κB p65.

[Preparation and application of biotinylated anti-AIB1 moniclonal antibody].

OBJECTIVE: To cross-link the McAb 1A2E1 to BNHS reagents and apply this biotinylated McAb to detect AIB1 antigen of target cells. METHODS: The McAb 1A2E1 was mixed with BNHS reagents to generate Biotin-1A2E1. The competitive inhibition ELISA and immunocytochemical method were applied to detect the biologic activity of antibody. RESULTS: The antibody kept high biological activities (with a titer of 1 : 3200) and sensitivities in detecting the AIB1 protein of breast cancer cell. CONCLUSION: The method of preparing biotinylated McAb is successful, and the prepared biotinylated McAb can be applied to detect target cells which express AIB1 antigen. This McAb provide useful tool for tumor auxiliary diagnosis.

[Production and identification of monoclonal antibody against N terminal of AIB1].

OBJECTIVE: To make and identify the monoclonal antibody against AIB1-N. METHODS: BALB/c mice were immunized with purified GST-AIB1-N protein, McAb against AIB1-N was produced by hybridoma technique. ELISA and Western-blot were used to identify the immunoglobin subtype and specificity. Results A hybridoma cell was successfully produced to secrete the McAb against AIB1-N, which was identified to belong in IgG1 subtype. By western-blot, the McAb against AIB1 displayed strongly specificity and high affinity. CONCLUSION: The McAb against AIB1 protein may be a useful tool for studying the biological properties of AIB1 expression and the clinical laboratory detection.