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The amphiphilic polymer has excellent performance and is expected to replace traditional polymer oil-displacing agent in China. In this study, the iso-viscosity method evaluates the oil displacement performance of the betaine-type amphiphilic polymers with different content of hydrophobic groups in high salinity reservoirs. Rheometer, emulsion stability analyzer, laser particle size analyzer, and visualization of microscopic displacement are used to explore their oil displacement mechanism. The results show that the content of hydrophobic groups, and the recovery ratio of polymer flooding shows a positive correlation. The difference in the displacement performance reflects the difference in the viscoelasticity of the displacement system and the ability to emulsify crude oil. The synergistic effect of the two aspects further improves the oil washing efficiency. This study provides a reference for the practical application of the amphiphilic polymer, providing a theoretical basis to select polymer flooding agents in high salinity reservoirs. [ABSTRACT FROM AUTHOR]

Cinnamoyl-CoA reductases (CCR) is a key enzyme in lignin biosynthesis. CCR mostly exists in the form of gene family in plants. In this study, four family members of CCR (BnCCR, BnCCR-1, BnCCR-2, and BnCCR-3) were screened and cloned by ramie transcriptome information. Sequence analysis revealed that the four BnCCRs can be divided into three categories. BnCCR belonged to bona fide CCR group, BnCCR-1 was a CCR like protein, while BnCCR-2 and BnCCR-3 sequences were different from bona fide CCR in NADPH binding domain, catalytic triad, and CCR substrate binding site, and formed a new group in ramie. Transmembrane structure analysis showed that BnCCR contained two transmembrane regions, and the other three BnCCRs didn't contain transmembrane regions. Structural analysis indicated that the secondary and tertiary structure of the four BnCCRs were different, and the BnCCR-2 homologous modeling template was different from the other three BnCCRs. The qRT-PCR analysis demonstrated that BnCCR had higher expression levels in xylem at rapid growth stage, BnCCR-2 had the highest expression levels in phloem at rapid growth stage. In vitro enzyme activity analysis further found that BnCCR had typical bona fide CCR catalytic activity and substrate adaptability, while BnCCR-2 was different from the substrate adaptability of typical CCR, and had substrate specificity for cinnamoyl CoA and sinapoyl CoA. Therefore, BnCCR was involved in lignin biosynthesis, while BnCCR-2 was a new group with structure, tissue expression and in vitro biochemical function different from typical CCR. BnCCR-2 may not participate or not only participate in lignin biosynthesis, which provides a new reference for studying the evolution of CCR protein family. [ABSTRACT FROM AUTHOR]