The complete chloroplast genome of an ornamental orchid, Vanda coerulescens (Orchidaceae).

Though the chloroplast genomes of several Vanda species have been sequenced, there is little information about the complete chloroplast (cp) genome of Vanda coerulescens. Herein, we established the cp genome of V. coerulescens. The chloroplast genome circle was 149,410 bp in length, with the structure of an 85,954 bp large single-copy (LSC) region and a 11,526 bp small single-copy (SSC) region, which separated by two inverted repeat (IRs) regions of 25,965 bp. It encoded 130 genes, including 74 protein-coding genes, 38 tRNA genes and 8 rRNA genes. The overall GC-content of the whole plastome is 36.7%, whereas the corresponding values of the LSC, SSC, and IR regions ranged from 28.2% to 43.1%. In addition, the phylogenetic analysis base on 20 chloroplast genomes of Orchidaceae indicates that V. brunnea is closely related to V. coerulescens. This announcement of the complete V. coerulescens cp genome sequence could provide valuable information for further genetic modification and phylogenetic study in Vanda genus.

The complete chloroplast genome of Liparis nervosa (Orchidaceae).

Liparis nervosa, a terrestrial orchid was widely used as a traditional medicinal plant in China. In this study, we assembled the complete chloroplast genome of L. nervosa using Illumina sequencing data. The whole genome is 158,716 bp, contains a large single-copy region (LSC 86,010 bp), a small single-copy region (SSC 18,276 bp), and a pair of inverted repeats (IR 27,215 bp). The complete genome has 132 genes, including 77 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. In addition, a maximum-likelihood phylogenetic analysis demonstrated that L. nervosa was most closely related to Oberonia japonica. This work provides a theoretical basis for the development of conservation strategies of L. nervosa.

Chloroplast characterizations and phylogenetic position of an endangered orchid, Vanda coerulea (Orchidaceae).

Vanda coerulea possess a high ornamental value and medical effect against glaucoma and cataract. The whole complete chloroplast (cp) genome of V. coerulea and the phylogenetic position based on the cp sequences remain unclear. Herein, we report the complete chloroplast genome of V. coerulea. The chloroplast genome was 149,376 bp in length, including a large single-copy (LSC) region of 86,100 bp, a small single-copy (SSC) region of 11,702 bp, and two inverted repeat (IRs) regions of 25,787 bp. A total of 129 genes were characterized, including 74 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. The overall GC content was 36.6%, and GC percentages range from 27.9% to 43.2% throughout LSC, IRs, and SSC regions. Phylogenetic analysis based on 20 chloroplast genomes of Orchidaceae indicated that V. coerulea is closely related to V. brunnea. Our study provides a valuable resource for the identification and distinction of Vanda genus, and will lay a foundation for further research and conservation measures of V. coerulea.

Morphological Variation and Recovery Mechanism of Residual Crude Oil by Biosurfactant from Indigenous Bacteria: Macro- and Pore-Scale Experimental Investigations.

Microbial enhanced oil recovery (MEOR) is being used more widely, and the biological contributions involved in MEOR need to be identified and quantified for the improvement of field applications. Owing to the excellent interfacial activity and the wide distribution of producing strains in oil reservoirs, lipopeptides have proved to be an essential part of the complex mechanisms in MEOR. In this study, crude lipopeptides were produced by a strain isolated from an indigenous community in an oil reservoir. It was found that crude lipopeptides can effectively reduce the IFT (interfacial tension) to 10(-1)~10(-2) mN/m under high salinity without forming stable emulsions, and the wettability of natural sandstone can be enhanced (Amott index, from 0.36 to 0.48). The results of core flooding experiments indicate that an additional 5.2% of original oil in place can be recovered with a 9.5% reduction of injection pressure. After the shut-in period, the wettability of the core, the reduction of injection pressure, and the oil recovery can be improved to 0.63, 16.2% and 9.6%, respectively. In the microscopic flooding experiments, the crude oil in membrane, cluster, and throat states contribute nearly 90% in total of the additional oil recovery, and the recovery of membranestate oil was significantly enhanced by 93.3% after shut in. Based on the results in macro and pore scale, the IFT reduction and the wettability alteration are considered primary contributors to oil recovery, while the latter was more dominant after one shut-in period.

[Formation mechanism of by-product PCBs in the p-DCB production].

A typical p-DCB production process was selected in this study. A series of p-DCB product samples, 1 Japanese sample and 1 chlorobenzene sample were collected and analyzed for by-product polychlorinated biphenyls (PCBs). It is a common phenomenon that byproduct PCBs exists in the p-DCB production process. The PCBs levels in the p-DCB samples were 62-781 ng/g and the highest WHO-TEQ in the process was 0.24 ng/g, while the PCBs level in the Japanese sample reached 881 ng/g. PCB31 was the dominate PCB congener in all the p-DCB samples with the maximum 98.5% of the total PCBs. Maximum content of PCBs was TrCBs in the p-DCB samples with the next TeCBs, DiCBs and PeCBs, while MoCBs were the highest in the chlorobenzene sample. Furthermore, a formation mechanism of PCBs in the production process was proposed and proved by the analysis result. It suggested that the formation of PCBs form the condensation of polychlorobenzenes had a relation with the concentration of polychlorobenzenes and the chlorine position in the benzene ring.