Numerous bacteria, including pollutant-degrading bacteria can enter the viable but nonculturable state (VBNC) when they encounter harsh environmental conditions. VBNC bacteria, as a vast majority of potent microbial resource can be of great significance in environmental rehabilitation. It is necessary to study the VBNC state of pollutant-degrading bacteria under various stress conditions. The aim of this study was to determine whether Rhodococcus biphenylivorans could enter the VBNC state under oligotrophic and low temperature conditions, and to examine the changes of morphology, enzymatic activity and gene expressions that might underline such state. The obtained results indicated that R. biphenylivorans TG9T could enter into the VBNC state and recover culturability under favorable environmental conditions. Results from Illumina high throughput RNA-sequencing revealed that the up-regulated genes related to ATP accumulation, protein modification, peptidoglycan biosynthesis and RNA polymerase were found in the VBNC cells, and the down-regulated genes mainly encoded hypothetical protein, membrane protein and NADH dehydrogenase subunit, which render VBNC cells more tolerant to survive under inhospitable conditions. This study provides new insights into prevention and control of the VBNC state of pollutant-degrading bacteria for their better capabilities in environmental rehabilitation.

No abstract

DNA methyltransferase 3B (DNMT3B) mediates gene silencing via epigenetic mechanisms during hepatocellular carcinoma (HCC) progression. We aimed to identify novel targets of DNMT3B and their potential regulatory mechanisms in HCC. Metastasis suppressor 1 (MTSS1) was one of the DNMT3B targets and selected for further study. DNMT3B overexpression was detected in 81.25% of clinical HCC specimens and was negatively associated with MTSS1 in HCC cells and clinical samples. The underlying mechanism by which DNMT3B silences MTSS1 was studied using a combination of methylation-specific polymerase chain reaction (PCR) and bisulfite genome sequencing, chromatin immunoprecipitation-PCR and luciferase reporter assays. We found that the MTSS1 promoter region was sparsely methylated, and the methylation inhibitors failed to abolish DNMT3B-mediated MTSS1 silencing. DNMT3B protein bound directly to the 5 0 -flanking region (À865/À645) of the MTSS1 gene to inhibit its transcription. The functional role of MTSS1 was investigated using in vitro and in vivo tumorigenicity assays. As a result, MTSS1 exerted tumor suppressor effects and arrested cells in the G2/M phase, but not the G1/S phase of the cell cycle when it was depleted or overexpressed in HCC cells. Taken together, MTSS1, a novel target of DNMT3B, is repressed by DNMT3B via a DNA methylation-independent mechanism. MTSS1 was further characterized as a novel tumor suppressor gene in HCC. These findings highlight how DNMT3B regulates MTSS1, and such data may be useful for the development of new treatment options for HCC.

A conventional plate count is the most commonly employed method to estimate the number of living bacteria in environmental samples. In fact, judging the level of viable culture by plate count is limited, because it is often several orders of magnitude less than the number of living bacteria actually present. Most of the bacteria are in "viable but non-culturable" (VBNC) state, whose cells are intact and alive and can resuscitate when surrounding conditions are more favorable. The most exciting recent development in resuscitating VBNC bacteria is a bacterial cytokine, namely, the resuscitation-promoting factor (Rpf), secreted by Micrococcus luteus, which promotes the resuscitation and growth of high G+C Gram-positive organisms, including some species of the genus Mycobacterium. However, most of studies deal with VBNC bacteria only from the point of view of medicine and epidemiology. It is therefore of great significance to research whether these VBNC state bacteria also possess some useful environmental capabilities, such as degradation, flocculation, etc. Further studies are needed to elucidate the possible environmental role of the VBNC bacteria, rather than only considering their role as potential pathogens from the point view of epidemiology and public health. We have studied the resuscitation of these VBNC bacteria in polluted environments by adding culture supernatant containing Rpf from M. luteus, and it was found that, as a huge microbial resource, VBNC bacteria could provide important answers to dealing with existing problems of environmental pollution. This mini-review will provide new insight for considering the potentially environmental functions of VBNC bacteria.

Atractylenolide I (ATL-1) is the major sesquiterpenoid of Atractylodes macrocephala. This study was designed to investigate whether ATL-1 induced apoptosis in A549 and HCC827 cells in vitro and in vivo. In our results, ATL-1 significantly decreased the percentage of in vitro viability, in a dose-dependent manner. In addition, DAPI staining and flow cytometry tests demonstrated the induction of apoptosis by ATL-I. Western blot analysis indicated that the protein levels of caspase-3, caspase-9 and Bax were increased in A549 and HCC827 cells after ATL-I exposure; to the contrary, the expressions of Bcl-2, Bcl-XL were decreased after treatment with ATL-1. In the in vivo study, ATL-I effectively suppressed tumor growth (A549) in transplanted tumor nude mice with up-regulation of caspase-3, caspase-9, and Bax and down-regulation of Bcl-2 and Bcl-XL. In conclusion, our results demonstrated that ATL-I has significant antitumor activity in lung carcinoma cells, and the possible mechanism of action may be related to apoptosis induced by ATL-I via a mitochondria-mediated apoptosis pathway.

BackgroundEGFR mutation is a strong predictor of efficacy of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKIs) therapy in advanced non-small cell lung cancer (NSCLC). However, around 20–30 % of EGFR-mutated cases showed no response to EGFR-TKIs, suggesting that other determinants beyond EGFR mutation likely exist. This study analyzed the role of microRNAs (miRNAs) in primary resistance to EGFR-TKIs in advanced NSCLC patients with EGFR mutation.MethodsTraining group: 20 advanced NSCLC patients with EGFR 19 deletion treated with first-line EGFR-TKIs were enrolled; half of them had dramatic responses while the other half had primary resistance. Matched plasma samples were collected for miRNA profiling using TaqMan low-density array (TLDA). Bioinformatics analyses were used to identify related miRNAs possibly accounted for resistance. Testing group: Quantitative reverse transcriptase PCR (qRT-PCR) was employed to detect the level of miRNA with significant differential expression in the training set. Validation group: Another cohort with EGFR 19 deletion mutations, who had dramatically different responses to EGFR-TKI, was used to validate the difference of miRNA expression between the sensitive and resistant groups using RT-PCR.ResultsTraining group: 153 miRNAs were found to be differentially expressed between the sensitive and resistant groups. Potential target genes were predicted with a target scan database. Twelve differentially expressed miRNAs were selected for the analysis because of their known roles in tumorigenesis of lung cancer, resistance to drugs, and regulation of EGFR pathway. Training group: three out of the 12 miRNAs (miR-21, AmiR-27a, and miR-218) were verified to have significantly higher expression (PmiR-21 = 0.004, PmiR-27a = 0.009, PmiR-218 = 0.041, respectively) in the resistant group compared to the sensitive group. Validation group: The expression levels of these three miRNAs were validated to be significantly different (P = 0.011, 0.011, 0.026, respectively) in the validation cohort (n = 34).ConclusionsHigher expression levels of miR-21, AmiR-27a, and miR-218 detected in this study suggest potential roles of these miRNAs in primary resistance to EGFR-TKI in advanced NSCLC patients with EGFR exon 19 deletion mutations. These findings need to be further confirmed in a study with a larger sample size.

There is no effective systemic therapy for patients with advanced hepatocellular carcinoma (HCC) except liver transplantation. Sorafenib, a multikinase inhibitor, has been shown to significantly increase overall survival (OS) in a randomized, placebo-controlled, phase III trial of patients with HCC (SHARP). The aim of this study was to evaluate the effectiveness of sorafenib for advanced HCC by carrying out a meta-analysis of randomized controlled trials that compared sorafenib-based therapy with other agent-based therapy. Randomized controlled trials comparing sorafenib or combined chemotherapy with placebo or combined chemotherapy in advanced HCC between 2000 and 2008 were identified and the data were extracted from reports. Outcomes analyzed were objective response rate, time to progression (TTP), OS, and toxicity. The summary hazard ratios (HRs), odds ratios, and their 95% confidence intervals (CIs) for mortality, objective response rate, and toxicity were estimated. All statistical tests were two-sided. Three trials including 924 patients were identified. Sorafenib-based chemotherapy was also associated with a 79% prolongation of TPP (HR = 0.58, 95% CI = 0.49-0.69, P<0.001), and a 37.3% increase in OS (HR = 0.66, 95% CI = 0.55-0.78, P<0.001). Despite significant increases in the frequencies of hand-foot syndrome and diarrhea in patients receiving sorafenib-containing chemotherapy, no significant difference in other toxic events was observed. This meta-analysis suggests that sorafenib-based chemotherapy is superior to placebo-based chemotherapy in terms of TPP and OS without increase in severe toxic effects.

No abstract