An investigation on lead, cadmium and methylmercury in seafood of Zhoushan City / 预防医学

Objective To analysis status of lead,cadmium and methylmercury residue in commercially available seafood during 2013-2015 in Zhoushan area.Methods During the period of 2013 to 2015,3 kinds of 1 134 seafood samples from representative farmer market in four districts of Zhoushan were collected to detect the lead,cadmium and methylmereury residue in seafish,mollusks and shellfish.Kruskal-Wallis rank-sum test were used to compare the difference of heavy metal residue in different years of seafood and exact propability were used to evaluate the difference of edible safety in different years.Results Of 1 134 seafood samples,the content of lead,cadmium and methylmereury was 0.011 5-0.555,0.0003-0.328,ND-0.302 mg/kg,respectively.The over-standard rate of lead in 2013 and 2015 were 0.79％ and 0.53％,found in five samples of seafish and shellfish,and the over-standard rate of cadmium in 2013 was 0.79％,found in three samples of seafish.Methylmercury residue in seafood wsa not found exceed the standard.Conclusion The contamination of lead,cadmium and methylmercury residue in commercially available seafood during 2013-2015 in Zhoushan area was in low level,but the content of lead and cadmium in seafood was over-standard.We should pay more attention to the lead content in shellfish,and lead and cadmium content in sea fish.

The Benefit Risk Assessment of Consumption of Marine Species Based on Benefit-Risk Analysis for Foods (BRAFO)-tiered Approach / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To assess the net health effect caused by the consumption of specific marine species based on Benefit-Risk Analysis for Foods (BRAFO)-tiered approach.</p><p><b>METHODS</b>Twenty species were collected from the Zhoushan Archipelago, China. Concentrations of n-3 long-chain polyunsaturated fatty acids, methyl mercury (MeHg), and dioxin-like compounds (DLCs) in the samples were analyzed for benefit risk assessment based on BRAFO-tiered approach.</p><p><b>RESULTS</b>Based on the BRAFO-tiered approach, reference scenario (no intake) and alternative scenario (intake of specific species of 200 g/week) were determined. The exposure to MeHg/DLCs via alternative scenario of all studied species did not exceed provisional tolerable weekly/monthly intake. However, the adult population with high DLCs exposure in China would significantly exceed the upper limit of DLCs via an additional alternative scenario of some species such as Auxis thazard. The results of deterministic computation showed that alternative scenario of all studied species generated clear net beneficial effects on death prevention and child IQ gain.</p><p><b>CONCLUSION</b>The alternative scenario of all studied species could be recommended to population with average DLCs exposure, and the reference scenario of species with relatively high DLCs concentration could be recommended to population exposed to high DLCs.</p>

Fatty acid composition of edible marine fish in Zhoushan, Zhejiang province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the main fatty acids in edible marine fish from Zhoushan, Zhejiang province.</p><p><b>METHODS</b>From September to October 2011, a total of 186 edible marine fish (31 species,6 individual fishes/species) were collected in local markets. Total lipids of edible part were extracted by Folch's method and fatty acids were separated and quantified by gas chromatographic after the homogenization of edible part. The differences of composition of n-6 polyunsaturated fatty acid (n-6 PUFA), n-3 polyunsaturated fatty acid (n-3 PUFA),saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) among fishes were analyzed.</p><p><b>RESULTS</b>Among the 31 fishes, total lipids were highest in Auxis thazard ((13.2 ± 1.2)g/100 g edible part) and lowest in Thamnaconus modestus ((0.6 ± 0.1)g/100 g edible part). Total n-6 PUFA were highest in Mugil cephalus ((875.7 ± 506.4)mg/100 g edible part) and lowest in Seriola quinqueradiata((2.1 ± 1.9)mg/100 g edible part). Total n-3 PUFA were highest in Auxis thazard ((2623.8 ± 426.1)mg/100 g edible part) and lowest in Scoliodon sorrakowah ((82.0 ± 13.9)mg/100 g edible part). SFA were highest in Trachinotus ovatus((3014.9 ± 379.0)mg/100 g edible part) and lowest in Seriola quinqueradiata ((89.7 ± 5.8)mg/100 g edible part). MUFA were highest in Coilia nasus ((3335.7 ± 383.5)mg/100 g edible part) and lowest in Thamnaconus modestus ((32.1 ± 16.9)mg/100 g edible part).</p><p><b>CONCLUSION</b>There were significant differences of composition of total lipids and of fatty acids among 31 edible marine fish species from Zhoushan.</p>

Expression of phytase gene in Bombyx mori / 生物工程学报

Phytase gene of Aspergillus niger 963 was cloned into baculovirus transfer vector. DNA of the recombinant vector was co-transfected with Bm-BacPAK6 DNA into BmN cells, and recombinant virus was selected by plaque assays. The recombinant virus was identified by Dot blot and Southern-blot with the specific probe for phytase gene. Phytase gene was expressed in silkworm larvae and pupae. The expression product was 1.43 g/L haemolymph for silkworm larvae and 1.90 g/L haemolymph for pupae, respectively. The enzymic characteristicses of phytase expressed in baculovirus-expression system were studied in this paper.

Cloning and Overexpression of Phytase Gene appA form Escherichia coli / 微生物学通报

A strain Escherichia coli with high production of phytase was screened from pig excreta. Phytase gene appA, with 1,299 bp coding region in full length, was cloned from its genome by polymerase chain reaction (PCR) . The gene appA was then cloned into the prokaryotic expression vector pET-28a ( + ) . In the host BL21, the phytase appA was overexpressed by shaker-cultivation (up to 692 U/mL) . The enzymatic analysis of the prokaryotic derived appA phytase revealed that its optimal pH and temperature was 4.5 and 60℃, respectively.