Due to rapid urbanization and the implementation of ecological civilization construction in China, many industrial factories have been closed or relocated. Therefore, numbers of contaminated sites were generated with contaminated soils which may pose a risk to receptors living nearby. This study presented a spatial health risk assessment and hierarchical risk management policy making for mercury (Hg) in soils from a typical contaminated site in the Hunan Province, central China. Compared with the second class value (0.3 mg/kg) of the Chinese Environmental Quality Standard for Soils, the mean concentrations of Hg in the three soil depths exceeded the second class value. The non-carcinogenic risk of Hg probably posed adverse health effects in 41, 30 and 36 % of the surface soil, the moderate soil and subsoil, respectively, under a sensitive land scenario. The non-carcinogenic risk temporarily posed no adverse health effects in most areas under an insensitive land scenario except for the area around sampling site S29. Spatially, the central, southwest and northeast parts of the contaminated land under a sensitive land scenario should be regarded as the priority regions. For non-carcinogenic effects, the exposure pathways that resulted in the higher levels of exposure risk were ingestion and inhalation of vapors, followed by dermal contact and inhalation of particles. A risk-based integrated risk management policy including the hierarchical risk control values for different soil depths and the calculated remediation earthwork was proposed with consideration of the cost-benefit effect for the related decision-makers.

In the biosynthesis of pentalenolactone (1), PenE and PntE, orthologous proteins from Streptomyces exfoliatus and S. arenae, respectively, catalyze the flavin-dependent Baeyer-Villiger oxidation of 1-deoxy-11-oxopentalenic acid (4) to the lactone pentalenolactone D (5), in which the less-substituted methylene carbon has migrated. By contrast, the paralogous PtlE enzyme from S. avermitilis catalyzes the oxidation of 4 to neopentalenolactone D (6), in which the more substituted methane substitution has undergone migration. We report the design and analysis of 13 single and multiple mutants of PntE mutants in order to identify the key amino acids that contribute to the regiospecificity of these two classes of Baeyer-Villiger monooxygenases. The L185S mutation in PntE reversed the observed regiospecificity of PntE such that all recombinant PntE mutants harboring this L185S mutation acquired the characteristic regiospecificity of PtlE, catalyzing the conversion of 4 to 6 as the major product. The recombinant PntE mutant harboring R484L exhibited reduced regiospecificity, generating a mixture of lactones containing more than 17% of 6. These in vitro results were corroborated by analysis of the complementation of the S. avermitilis ΔptlED double deletion mutant with pntE mutants, such that pntE mutants harboring L185S produced 6 as the major product, while complemention of the ΔptlED deletion mutant with pntE mutants carrying the R484L mutation gave 6 as more than 33% of the total lactone product mixture.

Abstract:The whole mitochondrial genome sequence of red fox (Vuples vuples) was determined. It had a total length of 16 723 bp. As in most mammal mitochondrial genome, it contained 13 protein coding genes, two ribosome RNA genes, 22 transfer RNA genes and one control region. The base composition was 31.3% A, 26.1% C, 14.8% G and 27.8% T, respectively. The codon usage of red fox, arctic fox, gray wolf, domestic dog and coyote followed the same pattern except for an unusual ATT start codon, which initiates the NADH dehydrogenase subunit 3 gene in the red fox. A long tandem repeat rich in AC was found between conserved sequence block 1 and 2 in the control region. In order to confirm the phylogenetic relationships of red fox to other canids, phylogenetic trees were reconstructed by neighbor-joining and maximum parsimony methods using 12 concatenated heavy-strand protein-coding genes. The result indicated that arctic fox was the sister group of red fox and they both belong to the red fox-like clade in family Canidae, while gray wolf, domestic dog and coyote belong to wolf-like clade. The result was in accordance with existing phylogenetic results.

No abstract

AIMTo explore the functional role of cullin 4A (CUL4A), a core subunit of E3 ubiquitin ligase, in perihilar cholangiocarcinoma (PHCC).METHODSThe expression of CUL4A in PHCC cell lines was evaluated by Western blot and quantitative reverse transcription-polymerase chain reaction. Immunohistochemistry (IHC) was adopted to investigate the relationship between CUL4A expression and clinicopathological characteristics of PHCC. Univariate analysis and multivariate regression analysis were performed to analyze the risk factors related to overall survival (OS) and progression-free survival (PFS) of PHCC patients. Wound healing, Transwell and Matrigel assays were utilized to explore the function of CUL4A in PHCC metastasis. Furthermore, expression of epithelial to mesenchymal transition (EMT) markers was verified in cells with CUL4A knockdown or overexpression. The relationship between CUL4A expression and E-cadherin expression was also analyzed by IHC assay. Finally, the role of ZEB1 in regulating CUL4A mediated PHCC was detected by IHC, Western blot, Transwell and Matrigel assays.RESULTSCUL4A overexpression was detected in PHCC cell lines and clinical specimens. Clinicopathological analysis revealed a close correlation between CUL4A overexpression and tumour differentiation, T, N and TNM stages in PHCC. Kaplan-Meier analysis revealed that high CUL4A expression was correlated with poor OS and PFS of PHCC patients. Univariate analysis identified the following four parameters as risk factors related to OS rate of PHCC: T, N, TNM stages and high CUL4A expression; as well as three related to PFS: N stage, TNM stage and high CUL4A expression. Further multivariate logistic regression analysis identified high CUL4A expression as the only independent prognostic factor for PHCC. Moreover, CUL4A silencing in PHCC cell lines dramatically inhibited metastasis and the EMT. Conversely, CUL4A overexpression promoted these processes. Mechanistically, ZEB1 was discovered to regulate the function of CUL4A in promoting the EMT and metastasis.CONCLUSIONCUL4A is an independent prognostic factor for PHCC, and it can promote the EMT by regulating ZEB1 expression. CUL4A may be a potential therapeutic target for PHCC.