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Huang G.,Key Laboratory of South China Sea Fishery Resources Exploitation | Huang G.,Protection Collaborative Innovation Center | Huang G.,CAS South China Sea Fisheries Research Institute | Guo Y.,Key Laboratory of South China Sea Fishery Resources Exploitation | And 12 more authors.
Gene | Year: 2016

Amylase is one of the most important digestive enzymes for phytophagous animals. In this study, the cDNA, genomic DNA, and promoter region of the α-amylase gene of the pearl oyster Pinctada fucata were cloned by using reverse transcription-polymerase chain reaction (RT-PCR), rapid amplification of cDNA ends, and genome-walking methods. The full-length cDNA sequence was 1704 bp long and consisted of a 5'-untranslated region of 17 bp, a 3'-untranslated region of 118 bp, and a 1569-bp open reading frame encoding a 522-aa polypeptide with a 20-aa signal peptide. Sequence alignment revealed that P. fucata α-amylase (Pfamy) shared the highest identity (91.6%) with Pinctada maxima. The phylogenetic tree showed that it was closely related to P. maxima, based on the amino acid sequences. The genomic DNA was 10850 bp and contained nine exons, eight introns, and a promoter region of 3932 bp. Several transcriptional factors such as GATA-1, AP-1, and SP1 were predicted in the promoter region. Quantitative RT-PCR assay indicated that the relative expression level of Pfamy was significantly higher in the digestive gland than in other tissues (gonad, gills, muscle, and mantle) (P < 0.001). The expression level at salinity 27‰ was significantly higher than that at other salinities (P < 0.05). Expression reached a minimum when the algal food concentration was 16 × 104 cells/mL, which was significantly lower than the level observed at 8 × 104 cells/mL and 20 × 104 cells/mL (P < 0.05). Our findings provide a genetic basis for further research on Pfamy activity and will facilitate studies on the growth mechanisms and genetic improvement of the pearl oyster P. fucata. © 2016 Elsevier B.V.

Gu Y.-G.,CAS South China Sea Fisheries Research Institute | Gu Y.-G.,Key Laboratory of Fishery Ecology and Environment of Guangdong Province | Gu Y.-G.,Key Laboratory of South China Sea Fishery Resources Exploitation | Gao Y.-P.,CAS Guangzhou Institute of Geochemistry | And 3 more authors.
Applied Geochemistry | Year: 2016

The total concentrations and oral bioaccessibility of heavy metals in surface-exposed lawn soils from 28 urban parks in Guangzhou were investigated, and the health risks posed to humans were evaluated. The descending order of total heavy metal concentrations was Fe > Mn > Pb > Zn > Cu > Cr > Ni > Cd, but Cd showed the highest percentage bioaccessibility (75.96%). Principal component analysis showed that Grouped Cd, Pb, Cr, Ni, Cu and Zn, and grouped Cr and Mn could be controlled two different types of human sources. Whereas, Ni and Fe were controlled by both anthropogenic and natural sources. The carcinogenic risk probabilities for Pb and Cr to children and adults were under the acceptable level (<1 × 10-4). Hazard Quotient value for each metal and Hazard Index values for all metals studied indicated no significant risk of non-carcinogenic effects to children and adults in Guangzhou urban park soils. © 2016 Elsevier Ltd.

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