Effects of Exogenous Lanthanum Nitrate on the Active Substance Content and Antioxidant Activity of Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes).

Cordyceps militaris is a medicinal and edible mushroom. Researchers often add exogenous substances to the culture medium to increase the active substance content in C. militaris.

Paternal reprogramming-escape histone H3K4me3 marks located within promoters of RNA splicing genes.

Motivation: Exposure of mouse embryos to atrazine decreased histone tri-methylation at lysine 4 (H3K4me3) and increased expression of alternatively spliced RNA in the third generation. Specificity protein (SP) family motifs were enriched in the promoters of genes encoding differentially expressed alternative transcripts.

Results: H3K4me3 chromatin immunoprecipitation sequencing (ChIP-seq) of mouse sperm, preimplantation embryo development and male gonad primordial germ cells (PGCs) were analysed to identify the paternal reprogramming-escape H3K4me3 regions (RERs).

Ecotoxicological effects of graphene oxide on the protozoan Euglena gracilis.

Potential environmental risks posed by nanomaterials increase with their extensive production and application. As a newly emerging carbon material, graphene oxide (GO) exhibits excellent electrochemical properties and has promising applications in many areas. However, the ecotoxicity of GO to organisms, especially aquatic organisms, remains poorly understood.

Inhibition mechanism of lanthanum ion on the activity of horseradish peroxidase in vitro.

In order to understand the inhibition mechanism of lanthanum ion (La(3+)) on the activity of horseradish peroxidase (HRP), the effects of La(3+) on the activity, electron transfer and conformation of HRP in vitro were investigated by using cyclic voltammetry (CV), atomic force microscopy (AFM), circular dichroism (CD), high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that La(3+) can combine with the amide groups of the polypeptide chain in HRP molecule, forming the complex of La(3+) and HRP (La-HRP). The formation of the La-HRP complex causes the destruction of the native structure of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure extent of active center, Fe(III) of the porphyrin ring of HRP molecule.

Inhibition mechanism of Tb(III) on horseradish peroxidase activity.

The inhibition mechanism of Tb(III) on horseradish peroxidase (HRP) in vitro was discussed. The results from MALDI-TOF/MS and X-ray photoelectron spectroscopy (XPS) showed that Tb(III) mainly interacts with the O-containing groups of the amides in the polypeptide chains of the HRP molecules and forms the complex of Tb(III)-HRP, and, in the complex, the molar ratio Tb(III)/HRP is 2 : 1. The results from CD and atomic force microscopy (AFM) indicated that the coordination effect between Tb(III) and HRP can lead to the conformation change in the HRP molecule, in which the contents of alpha-helix and beta-sheet conformation in the peptide of the HRP molecules is decreased, and the content of the random coil conformation is increased.

One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III).

One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III) was investigated using some biophysical and biochemical methods. Firstly, it was found that a large amount of Tb(III) can be distributed on the cell wall, that some Tb(III) can enter into the horseradish cell, indicating that peroxidase was mainly distributed on cell wall, and thus that Tb(III) would interact with horseradish peroxidase (HRP) in the plant. In addition, peroxidase bioactivity was decreased in the presence of Tb(III).

Subcellular location of horseradish peroxidase in horseradish leaves treated with La(III), Ce(III) and Tb(III).

The agricultural application of rare-earth elements (REEs) would promote REEs inevitably to enter in the environment and then to threaten the environmental safety and human health. Therefore, the distribution of the REEs ion, (141)Ce(III) and effects of La(III), Ce(III) and Tb(III) on the distribution of horseradish peroxidase (HRP) in horseradish mesophyll cells were investigated with electron microscopic radioautography and transmission electron microscopic cytochemistry. It was found for the first time that REEs ions can enter into the mesophyll cells, deposit in both extra and intra-cellular.

Spectroscopic studies of interactions involving horseradish peroxidase and Tb3+.

The spectroscopic properties of interactions involving horseradish peroxidase (HRP) and Tb3+ in the simulated physiological solution was investigated with some electrochemical and spectroscopic methods, such as cyclic voltammetry (CV), circular dichroism (CD), X-ray photoelectron spectroscopy (XPS) and synchronous fluorescence (SF). It was found that Tb3+ can coordinate with oxygen atoms in carbonyl groups in the peptide chain of HRP, form the complex of Tb3+ and HRP (Tb-HRP), and then lead to the conformation change of HRP. The increase in the random coil content of HRP can disturb the microstructure of the heme active center of HRP, in which the planarity of the porphyrin cycle in the heme group is increased and then the exposure extent of the electrochemical active center is decreased.

[Spectra studies on the interaction of Mn2+ and poly N-isopropylacrylamide].

The interaction of Mn2+ and poly (N-isopropylacrylamide) (PNIPAAm) was studied by using UV-Vis, FTIR and fluorescence spectroscopic methods. The results indicated that Mn2+ could be bonded to oxygen atoms of carbonyl in PNIPAAm and form the complex of Mn2+ -PNIPAAm. It was found that there existed efficient Förster energy transfer from Mn2+ to PNIPAAm due to the emission spectra of Mn2+ overlapping the excitation spectra of PNIPAAm and that the emission peak of Mn2+ at 561 nm disappeared in Mn2+ -PNIPAAm complex.