Identification and pathogenicity of Vibrio parahaemolyticus isolates and immune responses of Penaeus (Litopenaeus) vannamei (Boone).

Five different Vibrio parahaemolyticus strains (SH8, SH108, SH58, AH5 and GD10) isolated from the hepatopancreas of moribund shrimp in farms of mainland China were identified and capable of inducing massive mortality of Penaeus (Litopenaeus) vannamei. The immersion challenge results with five isolates indicated variance of virulence, while only GD10 caused massive sloughing of tubule epithelial cells which was recognized as the most significant symptom of AHPND. Differences in immune responses were detected of P. vannamei during 48 h post-infection (p.i.) by injection or immersion challenge with V. parahaemolyticus (SH8, SH108 and GD10) isolates. When injected SH8 and SH108 isolates, the expression of lysozyme (LSZ) showing statistically significant upregulation at 16 and 48 h p.i. and that of Toll-like receptors (TLR) showed statistically significant upregulation at 48 h p.i. When immersion challenge with the GD10 isolate, TLR were upregulated after 8 h p.i. challenge with 10(4)  cfu mL(-1) ; however, LSZ was downregulated when challenged with 10(3)  cfu mL(-1) . The results suggested that LSZ and TLR serve as crucial molecular markers of innate immunity in shrimp against V. parahaemolyticus infection. LSZ is a vital marker for acute bacterial infection, while TLR serves as a crucial marker for chronic infection.

Assessment of serum antioxidant status in patients with silicosis.

Prolonged exposure to silica dust causes an imbalance in the generation of free radicals and in the antioxidant system, thereby inducing oxidative stress. The antioxidant status of 113 silicosis patients and 116 control subjects without silicosis was examined. Serum superoxide dismutase (SOD) activity and serum levels of malondialdehyde (MDA) and glutathione (GSH) were significantly higher in silicosis patients than in controls. The GSH level in patients with stage I silicosis was higher than that in patients with other stages, but there was no difference in serum MDA level and SOD activity between disease stages. The GSH level of patients who worked with air drills was significantly lower than that of patients in other occupations, whereas the MDA level was significantly elevated in patients who used air drills. Serum SOD activity did not differ significantly according to the occupational group. It is concluded that the measurement of serum SOD, GSH and MDA levels could be beneficial in the clinical evaluation of serum antioxidant status in silicosis patients.