Response of hydrological ecosystem services to land-use change and risk assessment in Jiangxi Province, China.

Water bodies provide humans with important hydrological ecosystem services (HESs), directly or indirectly. Water yield, water conservation, and soil conservation are essential to HESs. Since China's reform and opening up, and with its rapid socio-economic development, land use in Jiangxi Province has undergone drastic change, resulting in threats to the ecological environment. This paper evaluates three HESs, water yield, water conservation, and soil conservation, in Jiangxi Province based on land use and rainfall data, quantifies the impacts of different land classes on each ecosystem, predicts future land use using the patch-generating land use simulation (PLUS) model, and finally, discusses the ecological risks in the study area. The following results were obtained: (1) The HESs in the basin increased and then decreased from 2000 to 2020, and the spatial distribution of water yield and water conservation was greatly influenced by rainfall. Soil conservation was mostly consistent with the elevation distribution. (2) Over time, the overall aggregation of HESs in the study area increased. There were small differences in the effects of various land uses on water yield and water conservation, and large differences in the effects on soil conservation. (3) The distribution of ecological risks was not affected by different land use strategies, with the lower ecological risk level 1 dominating. Most risk areas were present in Ganzhou, Ji'an, Shangrao, and Jiujiang. The ecological risk from urban sprawl (US) accounted for the most significant proportion, and that from the ecological protection (EP) strategy accounted for the lowest proportion. This study provides reference for sustainable land use development and ecological risk prevention in the study area.

Molecular detection of genotype II grass carp reovirus based on nucleic acid sequence-based amplification combined with enzyme-linked immunosorbent assay (NASBA-ELISA).

Grass carp reovirus (GCRV) is the causative agent of the grass carp hemorrhagic disease that has resulted in severe economic losses in the grass carp (Ctenopharyngodon idella) farming industry in China. Early diagnosis and vaccine administration are important priorities for GCRV control. In this study, a nucleic acid sequence-based amplification with enzyme-linked immunosorbent assay (NASBA-ELISA) was developed for to detect genotype II GCRV (GCRV- II). Primers specifically targeting viral RNA genome segment 6 were utilized for amplification in an isothermal digoxigenin-labeling NASBA process, resulting in DIG-labeled RNA amplicons. The amplicons were hybridized to specific biotinylated DNA probes and the products were detected colorimetrically using horseradish peroxidase and a microplate reader. The new method is able to detect GCRV at 14 copies/µL within 5h and had a diagnostic sensitivity and a specificity of 100% when GCRV-II and non-target virus were tested. This NASBA-ELISA was evaluated using a panel of clinical samples (n=103) to demonstrate that it is a rapid, effective and sensitive method for GCRV detection in grass carp aquaculture.