Fabp4 contributes toward regulating inflammatory gene expression and oxidative stress in Ctenopharyngodon idella.

Fatty acid-binding protein (Fabp)-4 is a member of the FABP family. Mammalian fabp4 has been demonstrated to involve in inflammation and immunity, whereas the related data of fish fabp4 remain limited. Therefore, we further investigated the effects of fabp4 on immunity in Ctenopharyngodon idella. The fabp4 sequence spanned 405 bp was cloned first, sharing high identity to fabp4 from other fish and mammals. Fabp4 expression was the highest in the adipose tissue, followed by the heart, muscle, and liver. In vivo, lipopolysaccharide (LPS) triggered the expression of fabp4, toll-like receptor (tlr)-22, interleukin (il)-1ß, and tumor necrosis factor (tnf)-α in the kidney and spleen. In vitro, exposing C. idella CIK cells to LPS decreased their viability, and the expression of fabp4 was also increased by LPS. However, BMS309403, an inhibitor of FABP4, mitigated these effects. Furthermore, treating the cells with LPS or fabp4 overexpression plasmids resulted in reactive oxygen species (ROS) generation and upregulation of inflammatory genes expression, including tlr22, type-I interferon (ifn-1), interferon regulatory factor (irf)-7, tnfα, il-1ß, and interferon-ß promoter stimulator 1. These effects were ameliorated by preincubation with BMS309403. Moreover, incubating the cells with glutathione reduced the production of ROS and the expression of inflammatory genes that were evoked by LPS and plasmid treatments. These results showed that fabp4 acts as a pro-inflammatory molecule via elevating ROS levels, providing a novel understanding of the molecular regulation of innate immunity in teleosts.

[Spatial response of lake water quality to multi-scale landscape pattern of lakeside zone in agricultural watershed].

Understanding the response of water quality in lake to landscape pattern at different spatial scales in agricultural watershed is of great significance to water quality management. In this study, we classified seven riparian buffer zones of lakeside zone by ArcGIS and RS in the Honghu Lake, according to the five functional areas. The landscape metrics were analyzed at multiple buffer widths using Fragstats software. Mathematical statistical methods and models such as redundancy analysis were used to explore spatial relationship between water quality and landscape patterns. Results showed that: 1) The effect of landscape patterns on water quality was scale-dependent at multiple buffer widths. The highest total explanatory power between landscape characteristics and water quality was found at the 200 m buffer width, accounting for 86.1% of the total, which was the most effective spatial scale affecting water quality. 2) The landscape configuration (e.g., largest patch index, patch density) was more associated with water quality than landscape composition (e.g., the percent of landscape and evenness index). 3) The impacts of different landscape types on water quality varied. Agriculture land, affected by topography and cultivation mode, was the main influencing factor on the degradation of water quality at smaller buffer widths from 100 m to 500 m. Forests with higher density and area had more purification effect on water pollutants at the wider buffer widths from 1000 m to 5000 m. The impacts of grassland on water quality was similar with that of forests, but densely distributed urban land contributed to water quality degradation at the same buffer widths. This study could provide scientific reference for water quality management and landscape planning of lake basin in agricultural areas.