Assessment of ecological conditions over China's coastal areas based on land use/cover change.

Studying the changes of land use and its impacts on ecological condition in coastal areas is of great significance for understanding the evolution of the regional ecological conditions and even global change. In this study, the study area encompassed 10 provincial administrative units of China's coastal areas, covering a total of 56 cities. Based on the land use and land cover data in 1980, 1990, 1995, 2000, 2005, 2010 and 2015 and the corresponding elevation data, we assessed ecological conditions and its temporal dynamic evolution and spatial differentiation characteristics with the ecological grade index method. The effects of the elevation differentiation and land-sea gradient on the ecological condition in China's coastal areas were analyzed. The results showed that the ecological conditions of China's coastal areas were basically stable and deteriorated on the whole although partially improved from 1980 to 2015. With Hangzhou Bay as a boundary-belt, ecological conditions in southern parts were better than that in the northern parts. The ecological grade index differed significantly with the variation of elevation. The areas with elevation below 10 m were in rela-tively poor ecological condition, and the regions below 30 m had the most obvious changes of ecological conditions. Moreover, the ecological conditions increased with elevation, with a gradual turnaround trend of improvement at above 400 m. There was a gradient characteristic of the ecological grade index in China's coastal areas, showing a high-low-high pattern from land to sea. Furthermore, the maximum value of ecological condition changes appeared at a distance of 10 km to the coastline, and the values decreased with the increasing of distance to the coastline.

Characterization of an aerobic denitrifier Pseudomonas stutzeri strain XL-2 to achieve efficient nitrate removal.

An aerobic denitrifier was newly isolated and identified as Pseudomonas stutzeri strain XL-2. Strain XL-2 removed 97.9% of nitrate with an initial concentration about 100 mg/L. Nitrogen balance indicates that 12.4% of the initial nitrogen was converted to N2O, and 62.4% was converted to N2. Single factor experiments indicate that the optimal conditions for nitrate removal were C/N ratio of 10, temperature of 30 °C and shaking speed of 120 rpm. Sequence amplification indicates that the denitrification genes of napA, nirS, norB and nosZ were present in strain XL-2. Combined with nitrogen balance, strain XL-2 presents the metabolic pathway of NO3- → NO2- → NO  →  N2O → N2 under aerobic conditions. The expression of napA and nirS might be responsible for the tolerance of dissolved oxygen by strain XL-2 during denitrification process.

Identification of Binding Modes for Amino Naphthalene 2-Cyanoacrylate (ANCA) Probes to Amyloid Fibrils from Molecular Dynamics Simulations.

The amino naphthalene 2-cyanoacrylate (ANCA) probe is a kind of fluorescent amyloid binding probe that can report different fluorescence emissions when bound to various amyloid deposits in tissue, while their interactions with amyloid fibrils remain unclear due to the insoluble nature of amyloid fibrils. Here, all-atom molecular dynamics simulations were used to investigate the interaction between ANCA probes with three different amyloid fibrils. Two common binding modes of ANCA probes on Aß40 amyloid fibrils were identified by cluster analysis of multiple simulations. The van der Waals and electrostatic interactions were found to be major driving forces for the binding. Atomic contacts analysis and binding free energy decomposition results suggested that the hydrophobic part of ANCA mainly interacts with aromatic side chains on the fibril surface and the hydrophilic part mainly interacts with positive charged residues in the ß-sheet region. By comparing the binding modes with different fibrils, we can find that ANCA adopts different conformations while interacting with residues of different hydrophobicity, aromaticity, and electrochemical properties in the ß-sheet region, which accounts for its selective mechanism toward different amyloid fibrils.