Biodegradation of decabromodiphenyl ether (BDE 209) by a newly isolated bacterium from an e-waste recycling area

Abstract Polybrominated diphenyl ethers (PBDEs) have become widespread environmental pollutants all over the world. A newly isolated bacterium from an e-waste recycling area, Stenotrophomonas sp. strain WZN-1, can degrade decabromodiphenyl ether (BDE 209) effectively under aerobic conditions. Orthogonal test results showed that the optimum conditions for BDE 209 biodegradation were pH 5, 25 °C, 0.5% salinity, 150 mL minimal salt medium volume. Under the optimized condition, strain WZN-1 could degrade 55.15% of 65 μg/L BDE 209 under aerobic condition within 30 day incubation. Moreover, BDE 209 degradation kinetics was fitted to a first-order kinetics model. The biodegradation mechanism of BDE 209 by strain WZN-1 were supposed to be three possible metabolic pathways: debromination, hydroxylation, and ring opening processes. Four BDE 209 degradation genes, including one hydrolase, one dioxygenase and two dehalogenases, were identified based on the complete genome sequencing of strain WZN-1. The real-time qPCR demonstrated that the expression level of four identified genes were significantly induced by BDE 209, and they played an important role in the degradation process. This study is the first to demonstrate that the newly isolated Stenotrophomonas strain has an efficient BDE 209 degradation ability and would provide new insights for the microbial degradation of PBDEs

Widely targeted metabolomic analysis reveals that volatile metabolites in cigar tobacco leaves dynamically change during fermentation

Changes in volatile metabolites during cigar tobacco leaves fermentation as well as the metabolic pathways of metabolites with significant differences were investigated to determine the influence of cigar tobacco leaves fermentation on its flavor. The volatile substances in cigar tobacco leaves at different stages were detected by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the main differences in volatile substances in cigar tobacco leaves at different fermentation stages of Yunxue1 in Yuxi production area were analyzed by principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). The results show that in the process of cigar tobacco leaves fermentation (YXF0, YXF1, YXF2, YXF3, YXF4, YXF5), a total of 613 volatile metabolites were detected, and a significant difference was found in 263 kinds of metabolites. Among them, the main upregulated differential metabolites were 1,3,6,10-Cyclotetradecatetraene, 3,7,11-trimethyl-14-(1-methylethyl)-, [S-(E,Z,E,E)]-, Benzoic acid, Benzaldehyde, etc. While the main downregulated differential metabolites included beta.-Myrcene, trans-Farnesol, etc. The metabolites with significant differences are mainly concentrated in the biosynthesis of monoterpenes, diterpenes, sesquiterpenes and triterpenes, the degradation metabolism of amino acids, such as valine, leucine and isoleucine, and the biosynthesis of phenylpropyl. There were 8 different metabolites in 5 groups, including 4- (1-methylethyl) -1-cyclohexene-1-formaldehyde、2, 4-dihydroxyacetophenone、2-methylbutyl 3-methylbutyrate and methylpyrazine, all of which showed upregulation trend during fermentation. In the fermentation process, volatile metabolites participate in various synthesis and degradation pathways. The biosynthesis pathway of terpenes and amino acid synthesis and degradation pathway are connected to produce various terpenes, aldehydes and other substances, such as 1,3,6,10-Cyclotetradecatetraene, 3,7,11-trimethyl-14-(1-methylethyl)-, [S-(E,Z,E,E)]-、benzaldehyde and 4-hydroxybenzaldehyde, which are conducive to the overall flavor and quality of cigar tobacco leaves

Changes in physicochemical properties and microbial community succession during leaf stacking fermentation

Abstract Leaf stacking fermentation involves enzymatic actions of many microorganisms and is an efficient and environmentally benign process for degrading macromolecular organic compounds. We investigated the dynamics of metabolite profiles, bacterial and fungal communities and their interactions during fermentation using cigar leaves from three geographic regions. The results showed that the contents of total sugar, reducing sugar, starch, cellulose, lignin, pectin, polyphenol and protein in cigar tobacco leaves was significantly decreased during fermentation. Notably, the furfural, neophytadiene, pyridine, benzyl alcohol, geranylacetone, 3-hydroxy-2-butanone, N-hexanal, 3-Methyl-1-butanol and 2,3-pentanedione were important features volatile aroma compounds during fermentation. The α-diversity of fungi and bacteria initially increased and then decreased during fermentation. An analysis of variance showed that microbial diversity was influenced by fermentation stages and growing locations, in which the all stages had greater impacts on α- and β-diversity than all regions. Microbiome profiling had identified several core bacteria including Sphingomonas, Bacillus, Staphylococcus, Pseudomonas, Ralstonia, Massilia and Fibrobacter. Fungal biomarkers included Aspergillus, Penicillium, Fusarium, Cladosporium and Trichomonascus. Interestingly, the molecular ecological networks showed that the core taxa had significant correlations with metabolic enzymes and physicochemical properties; bacteria and fungi jointly participated in the carbohydrate and nitrogen compound degrading and volatile aroma compound chemosynthesis processes during fermentation. These studies provide insights into the coupling of material conversion and microbial community succession during leaf fermentation. Graphical abstrac

Nab-paclitaxel plus S-1 in advanced pancreatic adenocarcinoma (NPSPAC): a single arm, single center, phase II trial

This single-arm, phase II trial is to investigate efficacy and safety of nab-paclitaxel plus S-1 as first-line treatment in advanced pancreatic cancer. Nab-paclitaxel was administered at 120 mg/m2 intravenously on day 1 and 8, S-1 was given twice a day orally on day 1-14 of each 21-day cycle, for 6 cycles. The primary endpoint was objective response rate (ORR), the secondary endpoints were progression-free survival (PFS), overall survival (OS) and safety. The ORR in intent-to-treat population (N=60) by either blinded independent review (BIR) or investigator assessment was 50.0%. Median PFS (mPFS) by BIR and median OS (mOS) were 5.6 months (95%CI, 4.6 to 6.6 m) and 9.4 months (95%CI, 8.0 to 10.8m), respectively. The most common grade 3 or 4 toxicities were leukopenia/neutropenia (35%) and fatigue (8.3%). Subgroup analyses based on BIR showed a remarkable ORR (>70%) was achieved in patients with female gender, ≥ 50% decline from baseline CA19-9, and developed grade 3 or 4 leukopenia/neutropenia. Remarkable survival benefit was statistically significant in female (mPFS: 7.7m, mOS: 18.2m), ≥ 50% decline from baseline CA19-9 (mPFS: 6.8m, mOS: 11.8m), objective responders (mPFS: 6.9m, mOS: 12.2m), and ECOG of 0 at baseline (mPFS: 7.5m, mOS: 16.1m). Nab-paclitaxel plus S-1 showed encouraging ORR and manageable toxicities, which is an effective alternative treatment regimen for advanced pancreatic cancer. (https://clinicaltrials.gov/ number, NCT02124317

High somatic mutations in circulating tumor DNA predict response of metastatic pancreatic ductal adenocarcinoma to first-line nab-paclitaxel plus S-1: prospective study

Abstract Aims We previously showed that the nab-paclitaxel plus S-1 (NPS) regimen had promising effects against metastatic pancreatic ducal adenocarcinoma (mPDAC), whose efficacy however could not be precisely predicted by routine biomarkers. This prospective study aimed to investigate the values of mutations in circulating tumor DNA (ctDNA) and their dynamic changes in predicting response of mPDAC to NPS chemotherapy. Methods Paired tumor tissue and blood samples were prospectively collected from patients with mPDAC receiving first-line NPS chemotherapy, and underwent next-generation sequencing with genomic profiling of 425 genes for ctDNA. High mutation allelic frequency (MAF) was defined as ≥ 30% and ≥ 5% in tumor tissue and blood, respectively. Kappa statistics were used to assess agreement between mutant genes in tumor and ctDNA. Associations of mutations in ctDNA and their dynamic changes with tumor response, overall survival (OS), and progression-free survival (PFS) were assessed using the Kaplan–Meier method, multivariable-adjusted Cox proportional hazards regression, and longitudinal data analysis. Results 147 blood samples and 43 paired tumor specimens from 43 patients with mPDAC were sequenced. The most common driver genes with high MAF were KRAS (tumor, 35%; ctDNA, 37%) and TP53 (tumor, 37%; ctDNA, 33%). Mutation rates of KRAS and TP53 in ctDNA were significantly higher in patients with liver metastasis, with baseline CA19-9 ≥ 2000 U/mL, and/or without an early CA19-9 response. κ values for the 5 most commonly mutated genes between tumor and ctDNA ranged from 0.48 to 0.76. MAFs of the genes mostly decreased sequentially during subsequent measurements, which significantly correlated with objective response, with an increase indicating cancer progression. High mutations of KRAS and ARID1A in both tumor and ctDNA, and of TP53, CDKN2A, and SMAD4 in ctDNA but not in tumor were significantly associated with shorter survival. When predicting 6-month OS, AUCs for the 5 most commonly mutated genes in ctDNA ranged from 0.59 to 0.84, larger than for genes in tumor (0.56 to 0.71) and for clinicopathologic characteristics (0.51 to 0.68). Repeated measurements of mutations in ctDNA significantly differentiated survival and tumor response. Among the 31 patients with ≥ 2 ctDNA tests, longitudinal analysis of changes in gene MAF showed that ctDNA progression was 60 and 58 days ahead of radiologic and CA19-9 progression for 48% and 42% of the patients, respectively. Conclusions High mutations of multiple driving genes in ctDNA and their dynamic changes could effectively predict response of mPDAC to NPS chemotherapy, with promising reliable predictive performance superior to routine clinicopathologic parameters. Inspiringly, longitudinal ctDNA tracking could predict disease progression about 2 months ahead of radiologic or CA19-9 evaluations, with the potential to precisely devise individualized therapeutic strategies for mPDAC

Correction to: Genetic characterization of Bacillus anthracis in Guizhou Province, Southwest of China

Abstract Erratum Upon publication of the original article (1) it was highlighted by the authors that a grant awarded to support the research work of the study was missed in the acknowledgements. It should also be acknowledged that the grant titled “Genotyping and Molecular Epidemiological Characteristic of Bacillus anthracis in Guizhou Province” awarded by the Program of Natural Science Foundation of Guizhou Province (Grant No. Qian Ke He J Word [2015] 2084)also contributed to the resources for this research. This has since been formally noted in this correction article