Zirong Xu

Oral vaccination with envelope protein VP28 against white spot syndrome virus in Procambarus clarkii using Bacillus subtilis as delivery vehicles

Aims:u2002 To achieve high‐level expression and secretion of active VP28 directed by a processing‐efficient signal peptide in Bacillus subtilis WB600 and exploit the possibility of obtaining an oral vaccine against white spot syndrome virus (WSSV) using vegetative cells or spores as delivery vehicles.

Protection of Procambarus clarkii against white spot syndrome virus using inactivated WSSV.

White spot syndrome virus (WSSV) is a highly pathogenic and prevalent virus infecting shrimp and other crustaceans. The potentiality of binary ethylenimine (BEI)-inactivated WSSV against WSSV in crayfish, Procambarus clarkii, was investigated in this study. Efficacy of BEI-inactivated WSSV was tested by vaccination trials followed by challenge of crayfish with WSSV. The crayfish injected with BEI-inactivated WSSV showed a better survival (P<0.05) to WSSV on the 7th and 21st day post-vaccination (dpv) compared to the control. Calculated relative percent survival (RPS) values were 77% and 60% on the 7th and 21st dpv for 2mM BEI-inactivated WSSV, and 63%, 30% on 7th and 21st dpv for 3mM BEI-inactivated WSSV. However, heat-inactivated WSSV did not provide protection from WSSV even on 7th dpv. In the inactivation process WSSV especially their envelope proteins maybe changed as happened to 3mM BEI and heat-inactivated WSSV particles. These results indicate the protective efficacy of BEI-inactivated WSSV lies on the integrity of envelope proteins of WSSV and the possibility of BEI-inactivated WSSV to protect P. clarkii from WSSV.

Immune responses of Fenneropenaeus chinensis against white spot syndrome virus after oral delivery of VP28 using Bacillus subtilis as vehicles

The protective efficacy of oral administration of VP28 using Bacillus subtilis as vehicles (rVP28-bs) in shrimp, Fenneropenaeus chinensis, upon challenge with white spot syndrome virus (WSSV) was investigated. The calculated relative percent survival (RPS) value of rVP28-bs fed shrimp was 83.3% when challenged on the 14th day post-administration, which is significantly higher (p < 0.001) than that of the group administered recombinant Escherichia coli over-expressing rVP28 (rVP28-e21). After immunization, activities of phenoloxidase (PO), superoxide dismutase (SOD) and inducible nitric oxide synthase (iNOS) in hemolymph were analyzed. It was found that the supplementation of rVP28-bs into shrimp food pellets resulted in the most pronounced increase of iNOS activity (p < 0.001), but had the least influence on activities of PO and SOD. Besides, in the shrimp orally administered with rVP28-bs, the caspase-3 activity was one-fifth that of the control, though the signs of apoptosis (chromatin margination, nuclear fragmentation and apoptotic bodies) could not be observed by transmission electron microscope (TEM). These results suggest that by oral delivery of rVP28-bs, shrimp showed significant resistance to WSSV and an effect on the innate immune system of shrimp. The remarkably enhanced level of iNOS after rVP28-bs administration might be responsible for antiviral defense in shrimp.

Mechanism of anti-angiogenic activities of chitooligosaccharides may be through inhibiting heparanase activity

Metastatic disease is the primary cause of death for most cancer patients. Angiogenesis is the formation of a new capillary network from pre-existing vessels and required for tumor vasculature. Heparanase, a beta-endoglucuronidase, assistants tumor invasion, metastasis and angiogenesis. Chitooligosaccharides (COS) is obtained by hydrolysis of chitosan. COS has been proved to be anti-angiogenesis activity. The mechanism of COS inhibits angiogenesis is not very clear, COS is hypothesized by author to be an inhibitor of heparanase.

Changes in Small Intestinal Morphology and Digestive Enzyme Activity with Oral Administration of Copper-Loaded Chitosan Nanoparticles in Rats

The experiment was conducted to evaluate the effect of copper-loaded chitosan nanoparticles on the small intestinal morphology and activities of digestive enzyme and mucosal disaccharase in rats. Forty male Sprague–Dawley rats, with average body weight of 82xa0g, were randomly allotted to five groups (nu2009=u20098). All rats were received a basal diet (control) or the same basal diet added with 80xa0mg/kg BW CuSO4, 80xa0mg/kg BW chitosan (CS-I), 80xa0mg/kg BW copper-loaded chitosan nanoparticles (CSN-I), 160xa0mg/kg BW copper-loaded chitosan nanoparticles (CSN-II), respectively. The experiment lasted 21xa0days. The results showed that the villus heights of the small intestinal mucosa in groups CSN-I and CSN-II were higher than those of the control, group CuSO4 or CS-I. The crypt depth of duodenum and ileum mucosa in group CSN-I or CSN-II was depressed. Compared with the control, there were no significant effects of CuSO4 or CS-I on the villus height and crypt depth of small intestinal mucosa. Supplementation with CSN improved the activities of trypsin, amylase and lipase in the small intestinal contents and maltase, sucrase and lactase of duodenum, jejunum, and ileum mucosa while there were no significant effects of CuSO4 on the digestive enzyme activities of the small content compared with the control. The results indicated that intestinal morphology, activities of digestive enzyme in digesta and mucosal disaccharase were beneficially changed by treatment of copper-loaded chitosan nanoparticles.

Effects of Montmorillonite on Pb Accumulation, Oxidative Stress, and DNA Damage in Tilapia (Oreochromis niloticus) Exposed to Dietary Pb

In order to investigate the effects of montmorillonite (MMT) on reducing dietary lead (Pb) toxicity to tilapia (Oreochromis niloticus), 240 fish were randomly divided into four treatments denominated as follows: control treatment (fed with a basal diet), MMT treatment (fed with a basal diet added with 0.5% MMT), Pb treatment (fed with a basal diet added with 100xa0mg Pb per kilogram dry weight (dw)), and Pbu2009+u2009MMT treatment (fed with a basal diet added with 100xa0mg Pb per kilogram dw and 0.5% MMT). Changes in Pb accumulation, oxidative stress, and DNA damage in tilapia were measured after 60xa0days. DNA damage was assessed using comet assay. The results showed that MMT supplemented in diet significantly reduced Pb accumulation in kidney and blood of tilapia exposed to dietary Pb (Pu2009<u20090.05). Malondialdehyde level decreased insignificantly while levels of total antioxidant capacity and glutathione (GSH), activities of glutathione peroxidase, and superoxide dismutase increased insignificantly in kidney of tilapia in Pbu2009+u2009MMT treatment as compared to Pb treatment (Pu2009>u20090.05). Significant decreases in tail length, tail DNA, tail moment, and Olive tail moment of peripheral blood cells in Pbu2009+u2009MMT treatment were observed when compared with Pb treatment (Pu2009<u20090.05). The results indicated that dietary MMT supplementation could alleviate dietary Pb toxicity to tilapia effectively.

Developmental patterns in hormone and lipid metabolism of growing Jinhua and Landrace gilts

The aim of the present study was to investigate the developmental patterns of lipid metabolism, hormones and growth factor in Jinhua and Landrace gilts. Six purebred gilts of each breed were selected and slaughtered for analyses at 35, 80, and 125 d of age, respectively. Jinhua gilts contained less lean meat (P < 0.01), and more carcass fat (P < 0.05) compared with Landrace gilts. Serum leptin, insulin-like growth factor I (IGF-I) and insulin levels increased with age, whereas, free triiodothyronine (FT3) and free thyroxine (FT4) levels decreased with age in both breeds (P < 0.05). Jinhua gilts had lower (P < 0.05) serum IGF-I, FT3 and FT4 levels, and higher (P < 0.05) serum leptin and insulin levels compared with Landrace gilts. Fatty acid synthase (FAS) activity of Jinhua gilts was higher than that of Landrace gilts (P < 0.001), whereas Jinhua gilts had lower hormone-sensitive lipase (HSL) activity (P < 0.001). Jinhua gilts had lower (P < 0.05) levels of free fatty acid (FFA) and triacylglycerol (TG). T...

Protection of Procambarus clarkii against white spot syndrome virus using recombinant subunit injection vaccine expressed in Pichia pastoris

The potentiality of injection vaccine against white spot syndrome virus (WSSV) in crayfish Procambarus clarkii was investigated. WSSV envelope proteins VP19 and VP28 were expressed in yeast Pichia pastoris GS115. The purified recombinant proteins (2 μg/g of crayfish) were injected intramuscularly, and the same dose injected as a booster shot on fifth day after vaccination. The vaccinated crayfish were divided into two even groups and later challenged orally by WSSV-infected dead crayfish muscle (2 g/individual) on the third and 21st days after the booster shot. The relative percent survival (RPS) in the third-day group was the highest in VP28 (91%), followed by VP19+VP28 (84%), and VP19 (45%). The RPS for the 21st-day group was the highest in VP28 (78%), followed by VP19+VP28 (76%), and VP19 (17%). Development of vaccine by using recombinant proteins VP19 and VP28 expressed in yeast is feasible.

Effects of Montmorillonite on Alleviating Dietary Cd-Induced Oxidative Damage in Carp (Carassius auratus)

The present study was designed to investigate the effects of montmorillonite (MMT) on dietary Cd-induced oxidative damage in liver and kidney of carp (Carassius auratus). One hundred eighty carp were randomly divided into four groups and fed with a basal diet, a basal diet supplemented with 0.5% MMT, Cd-comtaminated basal diet (120xa0mg Cd/kg dry weight) and Cd-contaminated basal diet supplemented with 0.5% MMT, respectively. After 60xa0days, fish were sacrificed to measure malondialdehyde (MDA) content and antioxidative indices in liver and kidney. The results showed that the exposure of carp to dietary Cd caused decreases in glutathione peroxidase activity, catalase activity, superoxide dismutase activity, glutathione content and total antioxidant capacity level, while MMT supplemented in diet compensated Cd-induced decreases in above antioxidant indices to some extent in liver and kidney. As compared with the control group, increases in MDA content were observed in both measured tissues of carp exposed to dietary Cd, while MDA content decreased in carp exposed to Cd-contaminated basal diet supplemented with MMT in comparison with the Cd-contaminated group. It was suggested that MMT, when co-administered with Cd in diet, could alleviate dietary Cd-induced oxidative damage in liver and kidney of carp.

Developmental changes of jejunal brush-border enzyme activity in growing Jinhua gilts.

Abstract The present study was aimed to investigate the developmental changes of small intestinal morphometry and jejunal brush-border enzyme activity in growing Jinhua gilts. The weight, length, and mucosa weight of the small intestine were measured at 35, 80 and 125 days of age, respectively. Sucrase, maltase, lactase and alkaline phosphatase (ALP) activities of the jejunal brush-border membrane were determined at the respective stages. Body weights and body weight gains significantly increased with age (P<0.05). Weights of the small intestine and of the intestinal mucosa increased faster from 35 to 80 d than from 80 to 125 d (P<0.05). Weights of the duodenum, jejunum, and ileum, and mucosa from the respective sections increased with age (P<0.05). Mucosa weight relative to the weight of the section was greater (P<0.05) for the duodenum, jejunum than for the ileum. Jejunal maltase and sucrase activity increased with age (P<0.05), whereas, lactose and ALP activity decreased with age (P<0.05) during growth. There was a 15-fold increase in both total jejunal maltase and sucrase activity from 35 to 125 days of age, and a 5-fold increase in both total jejunal lactase and ALP activity; the greatest rate of increase occurred between 35 and 80 days of age. The results suggest increases in body weight of growing Jinhua gilts are accompanied by significant developmental changes in intestinal weight, length and mucosal weights as well as jejunal brush border maltase, sucrase, lactase and ALP activities.