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Lian Fei Cao, Huo Qing Zheng, Qi Yan Shu, Fu Liang Hu and Zi Wei Xu

Abstract

China is the largest producer and exporter of royal jelly in the world. The high production of royal jelly in China is mainly attributed to a high royal jelly-producing lineage of honeybees (Apis mellifera) (HRJB). However, few studies have been conducted on the genetic characterization of HRJB. In this study, the mitochondrial DNA intergenic region between cytochrome oxidase I and II (COI-COII) and the mitochondrial NADH dehydrogenase subunit 2 sequences (ND2) were determined for 90 HRJB colonies, collected from the regions of China where HRJB originated, and 25 unimproved A. m. ligustica colonies from China. COI-COII sequence analysis revealed two mitotypes (C1 and C2d) in HRJB colonies and one mitotype (C1) in unimproved A. m. ligustica colonies. The main mitotype (C1) in HRJB accounted for 93% of the colonies. Based on ND2 sequences, four and two mitotypes were found in HRJB and unimproved A. m. ligustica colonies, respectively. Sequence alignment showed that nucleotides in three positions of the ND2 sequence were different between the main mitotype of HRJB and that of unimproved A. m. ligustica. Our study suggested that HRJB was bred from A. m. ligustica and possibly had genetic characteristics different from unimproved A. m. ligustica.

Open access

Fei Song, Haoyu Xia, Puyou Jia, Meng Zhang, Lihong Hu and Yonghong Zhou

Abstract

In this work, an environmentally friendly type plasticizer was introduced. The synthesis consisted of two steps. In the first step, castor oil (CO) was acrylated and then the acrylated castor oil (ACO) was epoxidized with the presence of formic acid and hydrogen peroxide in the second step. The epoxidized acrylated castor oil (EACO) was characterized by FTIR and 1H-NMR techniques. The EACO was used as a main plasticizer to obtain plasticized PVC materials and compared with DOP. The results showed that EACO improved polyvinyl-chloride (PVC) plasticization performance and reduced Tg from 81.06°C to 1.40°C. Plasticized PVC materials with EACO showed similar mechanical properties and better thermal stability than DOP. EACO had better volatility stabilities, migration and solvent extraction in PVC than DOP. EACO can be used to replace DOP to prepare soft films.

Open access

Lu-Lu Wang, Shi-Ying Lu, Pan Hu, Bao-Quan Fu, Yan-Song Li, Fei-Fei Zhai, Dan-Di Ju, Shi-Jun Zhang, Bing Su, Yu Zhou, Zeng-Shan Liu and Hong-Lin Ren

Abstract

Introduction: Peroxiredoxin 6 (Prdx6) is a bifunctional protein with glutathione peroxidase activity and phospholipase A2 activity. Previous studies have shown a significant positive correlation between the intracellular survival ability of Brucella and Prdx6. Here, the Prdx6 enzyme with a single activity was constructed to facilitate study of the relationship between the single function of Prdx6 and Brucella infection.

Material and Methods: The target open reading frame (ORF) DNAs of Prdx6 with a single active centre were prepared using gene splicing by overlap extension PCR (SOE-PCR), and the recombinant eukaryotic expression plasmids inserted by Prdx6 with the single activity centre were constructed and transfected into murine Raw264.7 macrophages. The glutathione peroxidase activity and phospholipase A2 activity of the constructed Prdx6 were examined.

Results: The core centres (Ser32 and Cys47) of Prdx6 were successfully mutated by changing the 94th nucleotide from T to G and the 140th nucleotide from G to C in the two enzyme activity cores, respectively. The constructed recombinant plasmids of Prdx6 with the single active centre were transfected into murine macrophages showing the expected single functional enzyme activity, which MJ33 or mercaptosuccinate inhibitors were able to inhibit.

Conclusion: The constructed mutants of Prdx6 with the single activity cores will be a benefit to further study of the biological function of Prdx6 with different enzyme activity.

Open access

Jingfei Jiang, Rongdong Hu, Fei Zhang and Yong Dou

Abstract

The Sparse Coding (SC) model has been proved to be among the best neural networks which are mainly used in unsupervised feature learning for many applications. Running a sparse coding algorithm is a time-consuming task due to its large scale and processing characteristics, which naturally leads to investigating FPGA acceleration. Fixed-point arithmetic can be used when implementing SC in FPGAs to reduce the execution time, but the implications for accuracy are not clear. Previous studies have focused only on accelerators using some fixed bitwidths on other neural networks models. Our work gives a comprehensive evaluation to demonstrate the bit-width effect on SCs, achieving the best performance and area efficiency. The method of data format conversion and the matrix blocking are the main factors considered according to the situation of hardware implementation. The simulation method of the simple truncation, the representation of the domain constraint and the matrix blocking with different parallelism were evaluated in this paper. The results have shown that the fixedpoint bit-width did have effect on the performance of SC. We must limit the representation domain of the data carefully and select an available bit-width according to the computation parallelism. The result has also shown that using a fixed-point arithmetic can guarantee the precision of the SC algorithm and get acceptable convergence speed.