[en] Plant diversity is hypothesized to strengthen biological control by promoting top-down pressure of predators on herbivores. However, studies on the effects of plant diversity on actual predation rates are still scarce, particularly in forest ecosystems. We analyzed the effect of tree species richness, and the potential influence of neighbor tree density, on predation rates of arthropods and birds on artificial clay caterpillars in a large-scale forest biodiversity experiment in south-east China. Our study was focused on three broadleaved tree species that are frequently damaged by lepidopteran caterpillars. Predation rates were influenced by tree species richness on only one of the three tree species, on which arthropod predation increased and bird predation decreased with increasing tree species richness. Importantly, these relationships were mediated by neighbor tree density, being most pronounced when focal trees had fewer surrounding neighbor trees. Our findings indicate that low tree density reduced arthropod predator abundances and predation rates, but that negative effects of this reduction were compensated for in more diverse tree mixtures by a functionally more diverse predator community. In contrast, lower tree densities might have benefited insectivorous birds by making trees more accessible particularly in monocultures, which are often structurally more uniform and denser than tree mixtures. Overall, our results point to an important role of species-specific and density-dependent mechanisms in modifying the consequences of biodiversity loss on top-down effects in forest ecosystems. Future work should aim at separating the effects of different predator guilds and those of host diversity from host density.

[en] The object of this study was to investigate differential proteomic expressions in sheep sperm protein under two doses (0.5 and 0.3 kGy) heavy ion radiation. The current research presented the protein changes using two-dimensional gel electrophoresis (2-DE) after staining with silver nitrate, differential expression proteins were detected by PDQuest 8.0 software and subjected to ion trap mass spectrometer equipped with a Surveyor HPLC system, and differential spots of protein were identified. Results showed that eight common different expressed protein spots in two doses 2D gels were identified to be three up-regulated proteins (glutaredoxin -1, transcription factor AP -2-alpha and enolase). It was concluded that there was significant difference at protein level in sheep sperm after heavy ion radiation and differential proteome expression analysis may be useful to clarify the physiology state of sheep sperm in heavy ion radiation, which laid a foundation for the further studies on heavy ion radiation of sheep sperm proteomics. (authors)

[en] Highlights: • We identified and characterized GmMYB3a of R2R3 myeloblastosis repressor family. • GmMYB3a is induced by various abiotic stresses. • For this study, we used a transgenic soybean over-expressing GmMYB3a. • We evaluated the photosynthesis index under salt-alkali treatments. • GmMYB3a was found to negatively affect the response of plants to salt stress. Myeloblastosis (MYB) transcription factor (TF) plays a positive role in the growth and stress response of plants; however, information on the functions of MYB repressors in soybean is limited. In the present study, the gene GmMYB3a was identified and characterized as a member of the R2R3 MYB repressor family, which is induced by various abiotic stresses. To understand the functions of GmMYB3a, a transgenic soybean over-expressing GmMYB3a was obtained and the photosynthetic index under salt–alkali treatments was evaluated. The transgenic line exhibited a series of negative regulation relative to the wild-type control. Quantitative real time polymerase chain reaction revealed that the physiological parameters, including soluble sugar, free proline, and chlorophyll contents; and photosynthetic rate decreased in the transgenic plants. Furthermore, GmMYB3a overexpression down-regulated a set of key genes associated with plant defense signal pathways. These finding suggest that GmMYB3a negatively affects the response of plants to salt stress.

[en] The objective of this study was to investigate the proteome changes induced by heavy ion radiation using irradiated ram sperm by a two-dimensional electrophoresis (2-DE) analysis. The 2D gels were stained with Coomassie Brilliant Blue. Differentially expressed proteins were detected by PDQuest 8.0 software and subjected to ion trap mass spectrometer equipped with a surveyor HPLC system, and differential protein spots were identified. Results showed there are five differential protein spots in irradiated sperm gels, four up-regulated protein spots and one spot missed. The differentially expressed protein spots were identified to be two up-regulated proteins including enolase, and enolase 1. It was concluded there was proteome changes induced by heavy ion radiation in ram sperm, which may be useful to clarify the physiology state of ram sperm in heavy ion radiation and provide a theoretical basis for radiation ram breeding. (authors)