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BackgroundNonviral vectors are attractively used for gene therapy owing to their distinctive advantages. Our previous study has demonstrated that transfer of human IFNγ gene into nasopharyngeal carcinoma (NPC) by using a novel nonviral vector, minicircle (mc), under the control of cytomegalovirus (CMV) promoter was effective to inhibit tumor growth. However, therapies based on CMV promoter cannot express the targeted genes in cancer tissues. Previous studies indicated that the development of human NPC was closely associated with Epstein-Barr virus (EBV) and demonstrated the transcriptional enhancer function of oriP when bound by EBV protein. Therefore, the present study is to explore the targeted gene expression and the anti-tumor effect of a novel tumor-specific gene therapeutic system (mc-oriP-IFNγ) in which the transgene expression was under the transcriptional regulation of oriP promoter.Methodology/Principal FindingsDual-luciferase reporter assay and ELISA were used to assess the expression of luciferase and IFNγ. WST assay was used to assess the cell proliferation. RT-PCR was used to detect the mRNA level of EBNA1. RNAi was used to knockdown the expression of EBNA1. NPC xenograft models in nude mice were used to investigate the targeted antitumor efficacy of mc-oriP-IFNγ. Immunohistochemistry was used to detect the expression and the activity of the IFNγ in tumor sections. Our results demonstrated that mc-oriP vectors mediated comparable gene expression and anti-proliferative effect in the EBV-positive NPC cell line C666-1 compared to mc-CMV vectors. Furthermore, mc-oriP vectors exhibited much lower killing effects on EBV-negative cell lines compared to mc-CMV vectors. The targeted expression of mc-oriP vectors was inhibited by EBNA1-siRNA in C666-1. This selective expression was corroborated in EBV-positive and -negative tumor models.Conclusions/SignificanceThis study demonstrates the feasibility of mc-oriP-IFNγ as a safe and highly effective targeted gene therapeutic system for the treatment of EBV positive NPC.

Macrobrachium rosenbergii is an important aquaculture species known as the king of freshwater prawn. Macrobrachium rosenbergii displays remarkable sexual dimorphism, yet our knowledge of the molecular mechanism underpinning sex determination and differentiation of M. rosenbergii is still fragmentary. In this study, through in silico prediction and experimental characterization, we identified a new Dmrt gene (Mr-Dsx) from M. rosenbergii. The cDNA of Mr-Dsx included a 115 bp 5′ untranslated region (UTR), a 2,568 bp open reading frame (ORF) and a 259 bp 3′ UTR. Mr-Dsx was expressed in a wide range of tissues, and showed dynamic expression changes at different moulting stages in the testis, androgenic gland (AG) and eyestalk. In response to unilateral eyestalk ablation (UEA), Mr-Dsx was significantly induced in the testis and AG. Gene knockdown of Mr-Dsx resulted in pronounced suppression of the insulin-like androgenic hormone (IAG) gene. The results suggest that Mr-Dsx is likely to be negatively regulated by the eyestalk neurohormones, and Mr-Dsx may participate in the transcriptional activation of IAG. The study characterized the potential roles of a newly identified Dmrt homologue from M. rosenbergii, and would contribute to a deeper understanding of the molecular regulatory network underlying sex differentiation and moulting of prawns. K E Y W O R D S crustacean, Dmrt, Macrobrachium rosenbergii, moulting, sexual differentiation

A 4-week feeding trial was conducted to determine the effects of oxidized fish oil (OFO, POV: 234.84 meq kg À1 ) on growth performance and oxidative stress of Litopenaeus vannamei. Five diets containing various OFO levels (0, 25, 50, 75 and 100 g kg À1 ) with the same dietary lipid level were fed to L. vannamei. The results showed that the body weight gain and the specific growth rate of the shrimp fed with 50, 75 and 100 g kg À1 of OFO diets decreased significantly (P < 0.05), whereas the hepatosomatic index increased significantly (P < 0.05). The malondialdehyde concentrations in the serum and muscle of the shrimp fed with 50, 75 and 100 g kg À1 of OFO diets were significantly higher than that of the shrimp fed with fresh fish oil (P < 0.05). The total antioxidant competence decreased significantly compared with the control group. Therefore, dietary OFO affects the growth performance and increases the oxidative stress of shrimp.

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The effect of air exposure on antioxidant activities in Pacific white shrimp Litopenaeus vannamei was studied. The behavioral changes in the shrimp and the levels of superoxide dismutase (SOD), malondialdehyde (MDA), and total antioxidant competence (T‐AOC) in the muscles and hepatopancreas were determined after the shrimp were exposed to air and then resubmersed in water. Results showed that the duration of air exposure significantly influenced shrimp survival. The maximum air exposure period during which the shrimp could remain alive was 30 min. After 10 min of air exposure, the shrimp could survive when they were resubmersed in water. The T‐AOC in the hepatopancreas and muscles was significantly decreased in shrimp that were exposed to air for 20 min. The MDA content in the hepatopancreas was significantly higher for the 20‐, 30‐, and 40‐min air exposure groups than for the control group. During the resubmersion period, the MDA content in the shrimp hepatopancreas and muscles increased. For shrimp that were exposed to air for 10 min, SOD activities in the hepatopancreas and muscles were restored after 3 h of resubmersion in water. Our results indicate that air exposure can cause oxidative damage to Pacific white shrimp, but the damage can be reversed after the shrimp are resubmersed.

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