A field experiment was carried out to study the changes of soil bacteria, fungi and actinomycetes in saline-sodic soils for different numbers of cultivated years under drip irrigation. The drip irrigation had substantial effects on levels of bacteria, fungi and actinomycetes. With increased number of cultivated years under drip irrigation, the soil biological properties were greatly improved. After three years of cultivation, the respective increases in the levels of bacteria, fungi and actinomycetes were 103.7, 72.7 and 58.2 times those of uncultivated land. In the vertical direction, the colony forming units of bacteria, fungi and actinomycetes all decreased with increased soil depth. We forecast that the soil microbial characteristics in drip-irrigated saline-sodic soils should match those of natural Leymus chinensis grassland after 6-7 years of cultivation.

Bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) have been shown to exhibit a synergistic effect to promote bone repair and healing. In this study, we constructed a novel adenovirus with high coexpression of BMP2 and bFGF and evaluated its effect on osteogenic differentiation of goat bone marrow progenitor cells (BMPCs). Recombinant adenovirus Ad-BMP2-bFGF was constructed by using the T2A sequence. BMPCs were isolated from goats by density gradient centrifugation and adherent cell culture, and were then infected with Ad-BMP2-bFGF or Ad-BMP2. Expression of BMP2 and bFGF was detected by ELISA, and alkaline phosphatase (ALP) activity was detected by an ALP assay kit. In addition, von Kossa staining and immunocytochemical staining of collagen II were performed on BMPCs 21 days after infection. There was a high coexpression of BMP2 and bFGF in BMPCs infected with Ad-BMP2-bFGF. Twenty-one days after infection, ALP activity was significantly higher in BMPCs infected with Ad-BMP2-bFGF than in those infected with Ad-BMP2. Larger and more mineralized calcium nodules, as well as stronger collagen II staining, were observed in BMPCs infected with Ad-BMP2-bFGF than in those infected with Ad-BMP2. In summary, we developed a novel adenovirus vector Ad-BMP2-bFGF for simultaneous high coexpression of BMP2 and bFGF, which could induce BMPCs to differentiate efficiently into osteoblasts.