Dynamic failure characteristics of surrounding rocks under different lateral pressure coefficients in deep tunnel transient excavation.

A novel transient unloading testing system was adopted to simulate the transient excavation of tunnels under different lateral pressure coefficients (k 0). The results show that the transient excavation of a tunnel induces significant stress redistributions and concentrations, particle displacements and vibrations to the surrounding rocks. The decrease of k 0 enhances the dynamic disturbance of transient tunnel excavation, and especially when k 0 = 0.4 and 0.2, the tensile stress can be observed on the top of the tunnel. The peak particle velocity (PPV) of the measuring points on the top of the tunnel decreases with the increasing distance between the tunnel boundary and measuring point. The transient unloading wave is generally concentrated on lower frequencies in the amplitude-frequency spectrum under the same unloading conditions, especially for lower k 0 values. In addition, the dynamic Mohr-Coulomb criterion was used to reveal the failure mechanism of a transient excavated tunnel by involving the loading rate effect. It is found that the excavation damaged zone (EDZ) of the tunnel is dominated by the shear failure, and the number of the shear failure zones increases with the decrease of k 0. The EDZ of tunnels after transient excavations varies from ring-shape to egg-shape and X-type shear with the decrease of k 0. The evolution of the EDZ induced by the transient unloading is associated with k 0, i.e., the shear failure of surrounding rocks mainly occurs in the stress redistribution stage under high k 0 (1.0-0.7), while the dramatic destruction of surrounding rocks is more prone to occur after the transient unloading process when k 0 ≤ 0.6.

Unnatural tetradeoxy echinocandins produced by gene cluster design and heterologous expression.

The hydroxyl groups in the amino acid residues of echinocandin B were related to the biological activity, the instability, and the drug resistance. The modification of hydroxyl groups was expected to obtain the new lead compounds for next generation of echinocandin drug development. In this work one method for heterologous production of the tetradeoxy echinocandin was achieved. A reconstructed biosynthetic gene cluster for tetradeoxy echinocandins composed of ecdA/I/K and htyE was designed and successfully hetero-expressed in Aspergillus nidulans. The target product of echinocandin E (1) together with one unexpected derivative echinocandin F (2), were isolated from the fermentation culture of engineered strain. Both of compounds were unreported echinocandin derivatives and the structures were identified on the basis of mass and NMR spectral data analysis. Compared with echinocandin B, echinocandin E demonstrated superior stability and comparable antifungal activity.

Presence, Mode of Action, and Application of Pathway Specific Transcription Factors in Aspergillus Biosynthetic Gene Clusters.

Fungal secondary metabolites are renowned toxins as well as valuable sources of antibiotics, cholesterol-lowering drugs, and immunosuppressants; hence, great efforts were levied to understand how these compounds are genetically regulated. The genes encoding for the enzymes required for synthesizing secondary metabolites are arranged in biosynthetic gene clusters (BGCs). Often, BGCs contain a pathway specific transcription factor (PSTF), a valuable tool in shutting down or turning up production of the BGC product. In this review, we present an in-depth view of PSTFs by examining over 40 characterized BGCs in the well-studied fungal species Aspergillus nidulans and Aspergillus fumigatus. Herein, we find BGC size is a predictor for presence of PSTFs, consider the number and the relative location of PSTF in regard to the cluster(s) regulated, discuss the function and the evolution of PSTFs, and present application strategies for pathway specific activation of cryptic BGCs.

Heteroexpression of Aspergillus nidulans laeA in Marine-Derived Fungi Triggers Upregulation of Secondary Metabolite Biosynthetic Genes.

Fungi are a prospective resource of bioactive compounds, but conventional methods of drug discovery are not effective enough to fully explore their metabolic potential. This study aimed to develop an easily attainable method to elicit the metabolic potential of fungi using Aspergillus nidulans laeA as a transcription regulation tool. In this study, functional analysis of Aspergillus nidulans laeA (AnLaeA) and Aspergillus sp. Z5 laeA (Az5LaeA) was done in the fungus Aspergillus sp. Z5. Heterologous AnLaeA-and native Az5LaeA-overexpression exhibited similar phenotypic effects and caused an increase in production of a bioactive compound diorcinol in Aspergillus sp. Z5, which proved the conserved function of this global regulator. In particular, heteroexpression of AnLaeA showed a significant impact on the expression of velvet complex genes, diorcinol synthesis-related genes, and different transcription factors (TFs). Moreover, heteroexpression of AnLaeA influenced the whole genome gene expression of Aspergillus sp. Z5 and triggered the upregulation of many genes. Overall, these findings suggest that heteroexpression of AnLaeA in fungi serves as a simple and easy method to explore their metabolic potential. In relation to this, AnLaeA was overexpressed in the fungus Penicillium sp. LC1-4, which resulted in increased production of quinolactacin A.

Flavobacterium ajazii sp. nov., Isolated from Seaweed of Gouqi Island, China.

A novel bacterium designated SSM4.2T was isolated from seaweed of Gouqi Island, which is the center of the Zhoushan fishing ground in the East China Sea. Strain SSM4.2T was Gram-stain-negative, bright yellow-pigmented, short rod-shaped, non-flagellated, non-spore forming, aerobic and motile by gliding. Growth was observed at 4-37 °C (optimum 25-30 °C), pH 6.0-8.0 (optimum pH 7.0) and 0-2.0% (w/v) NaCl (optimum 0%) concentration. The strain was catalase- and oxidase-positive. Menaquinone-6 (MK-6) was found as the sole respiratory quinone and zeaxanthin as the main carotenoid pigment. The predominant fatty acids (≥ 10%) were iso-C15:0, iso-C15:1 G, iso-C17:0 3-OH and summed feature 3 (C16:1 ω7c /C16:1 ω6c). The major polar lipid was phosphatidylethanolamine (PE). The genome size was 5.7 Mbp. The DNA G + C content was 34.1 mol%. 16S rRNA gene sequence revealed that strain SSM4.2T belongs to the genus Flavobacterium and shares high-sequence similarity with F. limi KACC 18851T (98.1%), F. hydrophilum KACC 19591T (97.6%), F. defluvii KCTC 12612T (97.1%), F. cheongpyeongense KACC 19592T (97.0%) and F. fluviatile KCTC 52446T (96.9%). Strain SSM4.2T had 73.2-84.6% average nucleotide identity and 19.1-29.4% digital DNA-DNA hybridization values with its closest type strains. Based on its phenotypic, chemotaxonomic, phylogenetic and genomic features, strain SSM4.2T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium ajazii sp. nov. is proposed. The type strain is SSM4.2T (= KCTC 72807T = MCCC 1K04370T).

Neoadjuvant Chemoradiotherapy and Larynx-Preserving Surgery for Cervical Esophageal Cancer.

Neoadjuvant concurrent chemoradiotherapy (CCRT) followed by surgery is widely used for treating locally advanced esophageal cancer in the thorax. This study evaluated the feasibility of neoadjuvant CCRT as a larynx preservation strategy for treating cervical esophageal squamous cell carcinoma (SCC) by a multidisciplinary team. Fifteen patients with cervical esophageal SCC who received neoadjuvant CCRT and radical surgery at our institution were reviewed. All patients received CCRT using the intensity-modulated radiation therapy with 48 Gy to gross tumor and 43.2 Gy to regional lymphatic basin in 24 fractions. Side effects, clinical tumor responses, pathological responses, and surgical margin status were analyzed. Pathological T down-staging was noted in seven patients (46.7%); pathological complete response was achieved in three patients (20%). Fourteen patients (93.3%) had larynx preservation; eight patients (53.3%) achieved negative surgical margins. The 2-year overall survival, local relapse-free survival, and regional relapse-free survival were 50.6%, 62.2%, and 47.5%, respectively. Neoadjuvant CCRT and larynx-sparing surgery are feasible and tolerable in patients with cervical esophageal SCC. Prospectively designed studies for large patient groups and long-term follow-up results are needed for validating this multimodality therapy.

Application of resistance gene analog markers to analyses of genetic structure and diversity in rice.

Plant disease resistance gene analog (RGA) markers were designed according to the conserved sequence of known RGAs and used to map resistance genes. We used genome-wide RGA markers for genetic analyses of structure and diversity in a global rice germplasm collection. Of the 472 RGA markers, 138 were polymorphic and these were applied to 178 entries selected from the USDA rice core collection. Results from the RGA markers were similar between two methods, UPGMA and STRUCTURE. Additionally, the results from RGA markers in our study were agreeable with those previously reported from SSR markers, including cluster of ancestral classification, genetic diversity estimates, genetic relatedness, and cluster of geographic origins. These results suggest that RGA markers are applicable for analyses of genetic structure and diversity in rice. However, unlike SSR markers, the RGA markers failed to differentiate temperate japonica, tropical japonica, and aromatic subgroups. The restricted way for developing RGA markers from the cDNA sequence might limit the polymorphism of RGA markers in the genome, thus limiting the discriminatory power in comparison with SSR markers. Genetic differentiation obtained using RGA markers may be useful for defining genetic diversity of a suite of random R genes in plants, as many studies show a differentiation of resistance to a wide array of pathogens. They could also help to characterize the genetic structure and geographic distribution in crops, including rice, wheat, barley, and banana.

Surgical results of synchronous multiple primary lung cancers: similar to the stage-matched solitary primary lung cancers?

BACKGROUND: Treatment for synchronous multiple primary lung cancers (SMPLC) remains controversial. Some surgeons treat SMPLC like advanced lung cancer, whereas other surgeons treat SMPLC as separate primary lung cancers. In this study, survival of SMPLC patients and matched-stage solitary primary lung cancer (SPLC) patients after surgical treatment were compared. METHODS: Prospective medical records between 2001 and 2011 were retrospectively reviewed. RESULTS: A total of 1,995 patients underwent pulmonary resection for lung cancer in a tertiary referral center. Only 97 patients met the modified criteria of Martini and Melamed for SMPLC. The median follow-up time was 38.3 months. The 3-year and 5-year overall survival rates were 83.1% and 69.6%, respectively. In the univariate analysis, males, smokers, and tumor size greater than 3 cm demonstrated significantly worse survival. After multivariate analysis, only tumor size (p = 0.018; hazard ratio 3.199) was identified as an independent predictor of survival. In addition, there was no significant difference in overall survival between the matched-stage SMPLC and SPLC without mediastinal lymph node involvement. Subgroup analysis in the multiple synchronous adenocarcinoma (n = 78) group demonstrated no significant difference between similar and different comprehensive histologic subtyping with respect to overall survival (61.3% versus 68.8%, p = 0.474). CONCLUSIONS: The surgical results for SMPLC were compatible and acceptable with those for SPLC even with similar histologic subtyping, instead of T4 or M1 stages in the current TNM classification system. Preoperatively, tumor size was the only independent prognostic factor for SMPLC with surgical intervention.