Microbial mixotrophic denitrification using iron(II) as an assisted electron donor.

Mixotrophic denitrification processes have a great potential in nitrogen removal in biological wastewater treatment processes. However, so far, few studies have focused on the mixotrophic denitrification system using Fe(II) as an exclusively assisted electron donors and the underlying mechanisms in such a process remain unclear. Furthermore, the mechanisms by which microorganisms cover carbon, nitrogen, phosphorus and iron in an iron-assisted mixotrophic system remain unrevealed. In this work, we explore the feasibility of using Fe(II) as an assisted electron donor for enhancing simultaneous nitrogen and phosphorus removal via long-term reactor operation and batch tests. The results show that Fe(II) could provide electrons for efficient nitrate reduction and that biological reactions played a predominant role in these systems. In these systems Thermomonas, a strain of nitrate-reduction Fe(II)-oxidation bacterium, was enriched and accounted for a maximum abundance of 60.2%. These findings indicate a great potential of the Fe(II)-assisted mixotrophic denitrification system for practical use as an efficient simultaneous nitrogen and phosphorus removal process.

MDM2 promotes epithelial-mesenchymal transition and metastasis of ovarian cancer SKOV3 cells.

BACKGROUND: Metastasis accounts for the most lethal reason for the death of ovarian cancer patients, but remains largely untreated. Epithelial-mesenchymal transition (EMT) is critical for the conversion of early-stage ovarian tumours into metastatic malignancies. Thus the exploration of the signalling pathways promoting EMT would open potential opportunities for the treatment of metastatic ovarian cancer. Herein, the putative role of MDM2 in regulating EMT and metastasis of ovarian cancer SKOV3 cells was investigated. METHODS: The regulatory effects by MDM2 on cell motility was emulated by wound-healing and transwell assays. The effects on EMT transition and Smad pathway were studied by depicting the expression levels of epithelial marker E-cadherin as well as key components of Smad pathway. To evaluate the clinical relevance of our findings, the correlation of MDM2 expression levels with the stages of 104 ovarian cancer patients was investigated by immunohistochemistry assay. RESULTS: We demonstrate that MDM2 functions as a key factor to drive EMT and motility of ovarian SKOV3 cells, by facilitating the activation of TGF-ß-Smad pathway, which results in the increased transcription of snail/slug and the subsequent loss of E-cadherin levels. Such induction of EMT is sustained in either E3 ligase-depleted MDM2 or E3 ligase inhibitor HLI-373-treated cells, while being impaired by the N-terminal deletion of MDM2, which is also reflected by the inhibitory effects against EMT by Nutlin-3a, the N-terminal targeting agent. The expression levels of MDM2 is highly correlated with the stages of the ovarian cancer patients, and the higher expression of MDM2 together with TGFB are closely correlated with poor prognosis and predict a high risk of ovarian cancer patients. CONCLUSIONS: This study suggests that MDM2 activates Smad pathway to promote EMT in ovarian cancer metastasis, and targeting the N-terminal of MDM2 can reprogram EMT and impede the mobility of cancer cells.

PSY-1, a Taxus chinensis var. mairei extract, inhibits cancer cell metastasis by interfering with MMPs.

Cancer is the most common disease worldwide, with death often occurring as a result of metastasis. Thus, interfering with metastasis has been regarded as a promising strategy to improve the current cancer treatments. However, exploration and development of novel anti-metastatic agents remains a major challenge. Recent evidence indicated that a polysaccharide isolated from Taxus yunnanensis suppressed tumor cells proliferation. With the objective of seeking bioactive extracts, we had previously isolated, purified and characterized a complex, water-soluble polysaccharides, PSY-1, from the leaves of Taxus chinensis var. mairei, and identified its anti-neoplastic effects. In this study, we focused on the effects of PSY-1 on cancer metastasis and its mechanism(s). The results illustrated that PSY-1 effectively suppressed the migration and invasion ability of the melanoma cancer cell line B16-F10, caused down-regulation of MMP-2 and MMP-9, and that the NF-kappaB pathway was involved in the anti-metastatic effects imposed by PSY-1.

DJ-1 mediates the resistance of cancer cells to dihydroartemisinin through reactive oxygen species removal.

Dihydroartemisinin (DHA), one of the main metabolites of artemisinin and its derivatives, presents anti-cancer potential in vitro and in vivo. To explore the mechanisms of resistance toward DHA, a DHA-resistant cell line, HeLa/DHA, was established with a resistance factor of 7.26 in vitro. Upon DHA treatment, apoptotic cells were significantly elicited in parental HeLa cells but minimally induced in HeLa/DHA cells. HeLa/DHA cells also displayed much less sensitivity to DHA-induced tumor suppression in cancer xenograft models than HeLa cells. Intriguingly, DHA-resistant cells did not display a multidrug-resistant phenotype. Based on a proteomic study employing LC-ESI-MS/MS together with pathway analysis, DJ-1 (PARK7) was found to be highly expressed in HeLa/DHA cells. Western blot and immunofluorescence assays confirmed the higher expression of DJ-1 in HeLa/DHA cells than in parental cells in both cell line and xenograft models. DJ-1 is translocated to the mitochondria of HeLa/DHA cells and oxidized, providing DJ-1 with stronger cytoprotection activity. Further study revealed that DJ-1 knockdown in HeLa/DHA cells abolished the observed resistance, whereas overexpression of DJ-1 endowed the parental HeLa cells with resistance toward DHA. Reactive oxygen species (ROS) were also significantly induced by either DHA or hydrogen peroxide in HeLa cells but not in resistant HeLa/DHA cells. When the cells were pretreated with N-acetyl-l-cysteine, the effect of DJ-1 knockdown on sensitizing HeLa/DHA cells to DHA was significantly attenuated. In summary, our study suggests that overexpression and mitochondrial translocation of DJ-1 provides HeLa/DHA cells with resistance to DHA-induced ROS and apoptosis.

[Smoking prevention and control among students of middle schools in Shanghai].

OBJECTIVE: To appraise the effectiveness of a school-based smoking control program and explore the effective smoking prevention and control intervention model in middle schools. METHODS: Through two phase cluster sampling, students in grade 1 and grade 2 of two schools were assigned to intervention group and control group. Comprehensive smoking intervention was implemented in the intervention group for one year. The assessment was carried out through three phases: baseline, after intervention, and 6-month after intervention. RESULTS: After intervention, the proportion of attempt smoking rate in the recent one year decreased from 9.7% to 4.2% and the heavy passive smoking rate declined from 15.5% to 12.2%. In addition, some knowledge, attitudes and skills related to tobacco prevention among the students in the intervention group were significantly improved and most effects can be sustained at 6-month follow up survey. CONCLUSION: It is concluded that tobacco control in middle school was effective and feasible and it should be closely integrated with tobacco control in the community.

[Smoking prevention and control among elementary school students in Xuhui district, Shanghai].

OBJECTIVE: To evaluate the effectiveness of a school-based smoking prevention and control intervention program among elementary school students. METHODS: Through two phase cluster sampling, 566 pupils in grade 4 and grade 5 of two schools were assigned to intervention group and control group. One year comprehensive smoking intervention was conducted in the intervention group. The assessment was carried out through three questionnaires: pre- and post-intervention, 6-month after intervention. RESULTS: After one year intervention, pupils in the intervention group significantly improved their knowledge and attitudes related to tobacco use. The rate of attempting smoking decreased form 7.8% to 2.6% and the rate of passive smoking from 53.6% to 41.8%. The difference between the intervention and control groups was statistically significant. However, several index started to decline at 6-month follow up survey. CONCLUSION: The result demonstrated the effectiveness and feasibility of tobacco control in elementary school and the positive effect must be developed.