Prediction of Ubiquitination Sites by Using the Composition of k-Spaced Amino Acid Pairs

As one of the most important reversible protein post-translation modifications, ubiquitination has been reported to be involved in lots of biological processes and closely implicated with various diseases. To fully decipher the molecular mechanisms of ubiquitination-related biological processes, an initial but crucial step is the recognition of ubiquitylated substrates and the corresponding ubiquitination sites. Here, a new bioinformatics tool named CKSAAP_UbSite was developed to predict ubiquitination sites from protein sequences. With the assistance of Support Vector Machine (SVM), the highlight of CKSAAP_UbSite is to employ the composition of k-spaced amino acid pairs surrounding a query site (i.e. any lysine in a query sequence) as input. When trained and tested in the dataset of yeast ubiquitination sites (Radivojac et al, Proteins, 2010, 78: 365–380), a 100-fold cross-validation on a 1∶1 ratio of positive and negative samples revealed that the accuracy and MCC of CKSAAP_UbSite reached 73.40% and 0.4694, respectively. The proposed CKSAAP_UbSite has also been intensively benchmarked to exhibit better performance than some existing predictors, suggesting that it can be served as a useful tool to the community. Currently, CKSAAP_UbSite is freely accessible at http://protein.cau.edu.cn/cksaap_ubsite/. Moreover, we also found that the sequence patterns around ubiquitination sites are not conserved across different species. To ensure a reasonable prediction performance, the application of the current CKSAAP_UbSite should be limited to the proteome of yeast

Identifying the structure of Zn-N-2 active sites and structural activation

Identification of active sites is one of the main obstacles to rational design of catalysts for diverse applications. Fundamental insight into the identification of the structure of active sites and structural contributions for catalytic performance are still lacking. Recently, X-ray absorption spectroscopy (XAS) and density functional theory (DFT) provide important tools to disclose the electronic, geometric and catalytic natures of active sites. Herein, we demonstrate the structural identification of Zn-N-2 active sites with both experimental/theoretical X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. Further DFT calculations reveal that the oxygen species activation on Zn-N-2 active sites is significantly enhanced, which can accelerate the reduction of oxygen with high selectivity, according well with the experimental results. This work highlights the identification and investigation of Zn-N-2 active sites, providing a regular principle to obtain deep insight into the nature of catalysts for various catalytic applications

Enhanced thylakoid photoprotection can increase yield and canopy radiation use efficiency in rice

High sunlight can raise plant growth rates but can potentially cause cellular damage. The likelihood of deleterious effects is lowered by a sophisticated set of photoprotective mechanisms, one of the most important being the controlled dissipation of energy from chlorophyll within photosystem II (PSII) measured as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity remains uncertain because it momentarily reduces the quantum efficiency of photosynthesis. Here we used plants overexpressing the gene encoding a central regulator of NPQ, the protein PsbS, within a major crop species (rice) to assess the effect of photoprotection at the whole canopy scale. We accounted for canopy light interception, to our knowledge for the first time in this context. We show that in comparison to wild-type plants, psbS overexpressors increased canopy radiation use efficiency and grain yield in fluctuating light, demonstrating that photoprotective mechanisms should be altered to improve rice crop productivity

Effect of high-pressure torsion on microstructure, mechanical properties and corrosion resistance of cast pure Mg

© 2018, The Author(s). High-pressure torsion (HPT) processing was applied to cast pure magnesium, and the effects of the deformation on the microstructure, hardness, tensile properties and corrosion resistance were evaluated. The microstructures of the processed samples were examined by electron backscatter diffraction, and the mechanical properties were determined by Vickers hardness and tensile testing. The corrosion resistance was studied using electrochemical impedance spectroscopy in a 3.5% NaCl solution. The results show that HPT processing effectively refines the grain size of Mg from millimeters in the cast structure to a few micrometers after processing and also creates a basal texture on the surface. It was found that one or five turns of HPT produced no significant difference in the grain size of the processed Mg and the hardness was a maximum after one turn due to recovery in some grains. Measurements showed that the yield strength of the cast Mg increased by about seven times whereas the corrosion resistance was not significantly affected by the HPT processing

Sentinel lymph node biopsy as guidance for radical trachelectomy in young patients with early stage cervical cancer

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to assess the feasibility and accuracy of sentinel lymph nodes (SLNs) detection using 99mTc phytate in predicting pelvic lymph nodes status for radical abdominal trachelectomy (RAT) in patients with early stage cervical cancer.</p> <p>Methods</p> <p>Sixty-eight women with stage IA2-IB1 cervical cancer and scheduled to undergo fertility-sparing surgery enrolled in this study. 99mTc-labeled phytate was injected before surgery. Intraoperatively, SLNs were identified, excised, and submitted to fast frozen section. Systematic bilateral pelvic lymphadenectomy and/or para-aortic lymph node dissection was performed. Then RAT was performed in patients with negative SLNs. All nodes were sent for routine pathological examination and immunostained with anti-cytokeratin antibody to detect micrometastases. Outcomes of follow up and fertility were observed.</p> <p>Results</p> <p>SLNs were identified in 64 of 68 patients (94.1%). Of these, SLNs of 8 patients (11.8%) were positive on frozen sections and proved to be metastasis by final pathologic examination. The sensitivity, accuracy, and false negative rates were 100%, 100%, and 0%, respectively. All 60 patients with negative SLN underwent RAT successfully. Two relapses occurred and no one died of tumor progression during follow-up. Five of the 15 patients with procreative desire conceived 8 pregnancies (3 term delivery, 2 premature birth, 1 spontaneous abortion, and 2 were still in the duration of pregnancy) after surgery.</p> <p>Conclusions</p> <p>The identification of SLN using 99mTc-labeled phytate is accurate and safe to assess pelvic nodes status in patients with early cervical cancer. SLNs biopsy guided RAT is feasible for patients who desire to have fertility preservation.</p

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Comparative Transcriptomes Profiling of Photoperiod-sensitive Male Sterile Rice Nongken 58S During the Male Sterility Transition between Short-day and Long-day

<p>Abstract</p> <p>Background</p> <p>Photoperiod-sensitive genic male sterile (PGMS) rice, Nongken 58S, was discovered in 1973. It has been widely used for the production of hybrid rice, and great achievements have been made in improving rice yields. However, the mechanism of the male sterility transition in PGMS rice remains to be determined.</p> <p>Results</p> <p>To investigate the transcriptome during the male sterility transition in PGMS rice, the transcriptome of Nongken 58S under short-day (SD) and long-day (LD) at the glume primordium differentiation and pistil/stamen primordium forming stages was compared. Seventy-three and 128 differentially expressed genes (DEGs) were identified at the glume primordium differentiation and pistil/stamen primordium forming stages, respectively. Five and 22 genes were markedly up-regulated (≥ 5-fold), and two and five genes were considerably down-regulated (≥ 5-fold) under SD during the male sterility transition. Gene ontology annotation and pathway analysis revealed that four biological processes and the circadian rhythms and the flowering pathways coordinately regulated the male sterility transition. Further quantitative PCR analysis demonstrated that the circadian rhythms of <it>OsPRR1, OsPRR37, OsGI, Hd1, OsLHY </it>and <it>OsDof </it>in leaves were obviously different between Nongken 58S and Nongken 58 under LD conditions. Moreover, both <it>OsPRR37 </it>and <it>Hd1 </it>in the inflorescence displayed differences between Nongken 58S and Nongken 58 under both LD and SD conditions.</p> <p>Conclusion</p> <p>The results presented here indicate that the transcriptome in Nongken 58S was significantly suppressed under LD conditions. Among these DEGs, the circadian rhythm and the flowering pathway were involved in the male sterility transition. Furthermore, these pathways were coordinately involved in the male sterility transition in PGMS rice.</p