The complete mitochondrial genome of Pseudofabraea citricarpa (Dermateaceae: Helotiales) causing Citrus target spot.

Pseudofabraea citricarpa (Dermateaceae: Helotiales) is known as a significant pathogen causing Citrus target spot disease and results in profound yield loss. In the present study, the complete mitochondrial genome (mitogenome) determined based on next-generation sequencing technology. The circular mitogenome (56,935 bp) comprised 14 conserved protein-coding genes (PCGs), 16 ORFs, two ribosomal RNA genes (rns and rnl), one non-coding RNA gene (rnpB), one ribosomal protein S3 (rps3) and 28 transfer RNA (tRNA) genes. The overall base composition is as follows: 36.08% A, 35.25% T, 13.04% C, and 15.63% G, with a GC content of 28.70%. The phylogenetic analysis shows that P. citricarpa, belonging to Dermateaceae, forms a separate clade and is sister to Sclerotiniaceae. The mitogenome of P. citricarpa reported in this study provides more molecular data for further research on the evolutionary relationships of Helotiales.

Polo-like kinase 4 is associated with advanced TNM stages and reduced survival and its inhibition improves chemosensitivity in colorectal cancer.

High expression of polo-like kinase 4 (PLK4) promotes tumorigenesis and is correlated with poor prognosis in several kinds of cancer. However, the prognostic value of PLK4 in colorectal cancer (CRC) has not been elucidated. The aim of the present study was to investigate the association between PLK4 and the prognosis and effect of PLK4 inhibition on chemosensitivity in CRC. A total of 142 patients with CRC were enrolled, and 142 pairs of CRC and para-carcinoma tissues were used to measure PLK4 protein expression using immunohistochemistry (IHC). Among them, 69 pairs were used to detect PLK4 mRNA expression using reverse transcription-quantitative PCR. In addition, PLK4-small interfering RNA (siRNA) was transfected into CRC cells, followed by 5-fluorouracil (5-FU) treatment for it was a fundamental chemotherapy for CRC. In addition, western blotting was used to detect PLK4 protein expression among human colonic epithelial cell and human CRC cell lines, including HCT-116, LoVo, SW480 and HT-29, as well as nuclear translocation of ß-catenin. The IHC score and mRNA expression of PLK4 were higher in CRC tissues compared with para-carcinoma tissues (both P<0.001). Furthermore, the IHC score of tumor PLK4 was not correlated with pathological grade (P=0.585), T stage (P=0.357), N stage (P=0.107225) or tumor-node-metastasis (TNM) stage (P=0.093). The mRNA expression of tumor PLK4 was positively correlated with N stage (P=0.019) and TNM stage (P=0.004), but not with pathological grade (P=0.498) or T stage (P=0.112). Of note, the high protein expression of tumor PLK4 was an independent factor for poor overall survival (OS; P=0.048). In addition, PLK4 was elevated in CRC cell lines; PLK4-siRNA reduced the 50% inhibitory concentration value of 5-FU in HCT-116 (4.4±0.1 µM vs. 7.6±1.4 µM) and LoVo cells (5.5±0.6 µM vs. 9.9±1.8 µM) (both P<0.05). Besides, PLK4-siRNA decreased nuclear translocation of ß-catenin. In conclusion, the high expression of tumor PLK4 was associated with advanced TNM stage and shorter OS in patients with CRC. In addition, targeting PLK4 improved chemosensitivity in CRC cells.

A Multi-Scale Simulation Study of Irradiation Swelling of Silicon Carbide.

Silicon carbide (SiC) is a promising structural and cladding material for accident tolerant fuel cladding of nuclear reactor due to its excellent properties. However, when exposed to severe environments (e.g., during neutron irradiation), lattice defects are created in amounts significantly greater than normal concentrations. Then, a series of radiation damage behaviors (e.g., radiation swelling) appear. Accurate understanding of radiation damage of nuclear materials is the key to the design of new fuel cladding materials. Multi-scale computational simulations are often required to understand the physical mechanism of radiation damage. In this work, the effect of neutron irradiation on the volume swelling of cubic-SiC film with 0.3 mm was studied by using the combination of molecular dynamics (MD) and rate theory (RT). It was found that for C-vacancy (CV), C-interstitial (CI), Si-vacancy (SiV), Si-interstitial (SiI), and Si-antisite (SiC), the volume of supercell increases linearly with the increase of concentration of these defects, while the volume of supercell decreases linearly with the increase of defect concentration for C-antisite (CSi). Furthermore, according to the neutron spectrum of a certain reactor, one RT model was constructed to simulate the evolution of point defect under neutron irradiation. Then, the relationship between the volume swelling and the dose of neutrons can be obtained through the results of MD and RT. It was found that swelling typically increases logarithmically with radiation dose and saturates at relatively low doses, and that the critical dose for abrupt transition of volume is consistent with the available experimental data, which indicates that the rate theory model can effectively describe the radiation damage evolution process of SiC. This work not only presents a systematic study on the relationship between various point defect and excess volume, but also gives a good example of multi-scale modelling through coupling the results of binary collision, MD and RT methods, etc., regardless of the multi-scale modelling only focus on the evolution of primary point defects.