Codon usage characteristics of PB2 gene in influenza A H7N9 virus from different host species.

The influenza A H7N9 virus is a highly contagious virus which can only infect poultry before early 2013. But after that time, it widely caused human infections in China and brought Southeast Asia great threaten in the public health area. The coding gene for polymerase basic protein 2 (PB2) in influenza A H7N9 virus encodes the PB2 protein, which is a part of the RNA polymerase. The enzyme lacks a correction function during its own replication process, so the mutation frequency of the influenza A H7N9 virus gene is high and the PB2 gene is also included. To investigate the codon usages characteristics of PB2 gene, gene sequences of 12 kinds of poultry are downloaded form the gene bank (NCBI) and their codon usage characteristics such as the effective number of codons (ENC), the evolutionary relationship of the sequences, the codon adaptation index (CAI), the correspondence analysis (COA), the relative synonymous codon usage (RSCU) and their PR2-bias are compared and studied. The value of these reults showed that there is a low codon usage bias in the PB2 gene. Then, the differences between the codon usages of PB2 gene from 12 kinds of poultry are compared and their potential applications are discussed. These results could lay a foundation for other further study on the evolution of H7N9.

Comprehensive Analysis and Comparison on the Codon Usage Pattern of Whole Mycobacterium tuberculosis Coding Genome from Different Area.

Phenomenon of unequal use of synonymous codons in Mycobacterium tuberculosis is common. Codon usage bias not only plays an important regulatory role at the level of gene expression, but also helps in improving the accuracy and efficiency of translation. Meanwhile, codon usage pattern of Mycobacterium tuberculosis genome is important for interpreting evolutionary characteristics in species. In order to investigate the codon usage pattern of the Mycobacterium tuberculosis genome, 12 Mycobacterium tuberculosis genomes from different area are downloaded from the GeneBank. The correlations between G3, GC12, whole GC content, codon adaptation index, codon bias index, and so on of Mycobacterium tuberculosis genomes are calculated. The ENC-plot, relationship between A3/(A3 + T3) and G3/(G3 + C3), GC12 versus GC3 plot, and the RSCU of overall/separated genomes all show that the codon usage bias exists in all 12 Mycobacterium tuberculosis genomes. Lastly, relationship between CBI and the equalization of ENC shows a strong negative correlation between them. The relationship between protein length and GC content (GC3 and GC12) shows that more obvious differences in the GC content may be in shorter protein. These results show that codon usage bias existing in the Mycobacterium tuberculosis genomes could be used for further study on their evolutionary phenomenon.

Design and experiment of a neural signal detection using a FES driving system.

The channel bridging, signal regenerating, and functional rebuilding of injured nerves is one of the most important issues in life science research. In recent years, some progresses in the research area have been made in repairing injured nerves with microelectronic neural bridge. Based on the previous work, this paper presents a neural signal detection and functional electrical stimulation (FES) driving system with using high performance operational amplifiers, which has been realized. The experimental results show that the designed system meets requirements. In animal experiments, sciatic nerve signal detection, regeneration and function rebuilding between two toads have been accomplished successfully by using the designed system.