ABSTRACT
A detection method for furazolidone and florfenicol in soil with various environmental matrices was established using ultra performance liquid chromatography-tandem spectrometry (UPLC / MS / MS) technique. Extracting solution of a mixture of phosphate buffer (pH = 3) and acetonitrile (3 : 7, V/ V) was used in this experiment. The extracted water samples were enriched by SAX-HLB solid phase extraction column before the process of nitrogen blowing ( high purity nitrogen). The enriched antibiotics were desalted with 8 mL of methanol. Waters BEH C18(2. 1 × 100 mm) column was used for the sample separation. UPLC / MS / MS was carried out for qualitative and quantitative analysis under multi-reaction monitoring mode. The detection limit of the method was determined by 3 times of signal-to-noise ratio, and the limit of determination of the method was determined by 10 times of signal-to-noise ratio. The results showed that the detection limits of furazolidone and florfenicol were 1. 19 and 0. 41 μg / kg, respectively, and the limits of quantitation of furazolidone and florfenicol were 3. 40 and 1. 37 μg / kg, respectively. Besides, recovery experiment showed that, for the soil samples spiked with 50 μg / L furazolidone and florfenicol, the recoveries were 79% for florfenicol and 92% for furazolidone. Similarly, for the soil samples spiked with 200 μg / L furazolidone and florfenicol, the recoveries were 96% for furazolidone and 86% for florfenicol.
ABSTRACT
The cytolytic effect of perforin is a mechanism of anti-virus,killing microbial-infected cells and tumor cells.Perforin is a very important non-specific immune factors in fish.In order to understand the function of perforin,the cDNA of grass carp perforin C-terminal peptide was amplified from grass carp liver and kidney cDNA library.It contains a protein kinase C conserved region 2(C2).The cDNA was connected with pET32a,and transformed to expression bacteria DE3.PFP-C was expressed by a prokaryotic expression system and then purified by affinity chromatography.It showed a significant haemolytic activity when tested with rabbit red cells,the optimal pH for haemolytic activity was 7.5,and its haemolytic function dependents on Ca2+ apparently.