ABSTRACT
The rice gall dwarf disease, caused by the Rice gall dwarf virus (RGDV) is a serious disease occurring in rice in many regions of Guangdong province. As a basis to control the disease we have studied the genomic diversity of a variety of isolates from different locations. Genome segment 8(S8), encoding a main outer capsid protein (Pns8) of RGDV five isolates (BL, CH, DQ, GZ, XY) from Guangdong province was cloned and sequenced. The results revealed that all the S8 segments of the five isolates consisted of 1 578 nucleotides and had a single open reading frame (ORF) extending for 1 301 nucleotides from nucleotide 21 which encoded a polypeptide of 426 amino acids with an estimated molecular weight of 47.4 kDa. The S8 full-length sequence and the ORF sequence shared 97.3%-98.8% and 97.3%-99.1% nucleotide sequence identities within the five Chinese isolates, and shared 94.8%-95.6% and 95.0%-96.0% identities with those of the Thailand isolate respectively. The deduced amino acid sequence of Pns8 in GZ isolate was identical to that in the Thailand isolate, while the amino acid sequence variability of Pns8 within five Chinese isolates ranged from 0.5% to 2.1%. These results indicate that the S8 segment of RGDV is highly conserved in different isolates from different locations. The S8 cDNA from the XY isolate was cloned into the plasmid vector pET-28b(+) and a fused expression protein with an apparent molecular mass of 51kDa was specifically detected in an analysis of Escherichia coli Rossetta(DE3)Ⅱcells. To our knowledge, this is the first report on analysis of the RGDV segment 8 sequence and genetic comparison of different RGDV isolates and their protein expression.
ABSTRACT
Butyric acid can be used to produce cellulose butyrate fiber and ester derivatives,and to be applied in foodstuffs and perfume industries.Recent researches have found that butyric acid is a preferred carbon source for colonic epithelial cells,and can inhibit histone deacetylase,showing great anticancer potentials.With more and more functions of butyric acid being found and applied in bio-related fields,and with consumer's growing preference to bioproducts,biotechnological production of butyric acid will receive more competence than petroleum-based chemical synthesis.Low product concentration and poor selectivity are presently the main restricting factors.Workers have made considerable progress on more cheep carbon sources,optimization of fermentation process,simplifying downstream processing,and genetic engineering of producing strains.Any achievement on these aspects in the future can contribute to put fermentation of butyric acid into industry.