Plant virus-based
nanoparticles are used as self-assembled protein
scaffolds for the construction of enzyme nanocarriers. To date, one-pot
production and coupling of both enzymes and scaffolds by genetic conjugation
have been demonstrated only in plants. Herein, we report bacterial
production and in vitro self-assembly of nanofilaments
for CO2 capture. Filamentous virus-like particles (VLPs)
were successfully formed by genetically fusing carbonic anhydrase
from Hydrogenovibrio marinus (hmCA) to the N terminus of the coat protein (CPPVY) of potato virus Y with a flexible linker. The instability of VLPs
against proteolytic degradation was circumvented by the periplasmic
export of the fusion protein. The truncated form of CPPVY coexpressed by internal translation was crucial for the successful
formation of long filamentous VLPs by alleviating steric hindrance via hybrid assembly. The fast and economic bottom-up fabrication
of highly active nanobiocatalyst allows the nanofilaments to be efficiently
used and recovered in potential biocatalytic and biosensor systems.
Carbonic anhydrase (CA) is an ultrafast enzyme that catalyzes the reversible conversion of carbon dioxide (CO2) to bicarbonate. CA is considered to be a green catalyst for enzyme-based CO2 capture and utilization. In particular, the CA of Thermovibrio ammonificans (taCA) has attracted increasing attention as a highly stable enzyme. However, the poor solubility and the low expression level in Escherichia coli have hampered further utilization of taCA. In a recent study, these limitations were partly resolved by using a small solubility-enhancing fusion tag named NEXT, which originates from the N-terminal extension of Hydrogenovibrio marinus CA. In this study, the NEXT tag was engineered by adding small peptides to the N terminus to further increase the production yield of NEXT-tagged taCA. The addition of ng3 peptide (His-Gly-Asn) originating from the N-terminal sequence of Neisseria gonorrhoeae CA improved the expression of NEXT-taCA, while the previously developed translation-enhancing element (TEE) and Ser-Lys-Ile-Lys (SKIK) tag were not effective. The expression test with all 16 codon combinations for the ng3 sequence revealed that the change in translation initiation rate brought about by the change in nucleotide sequence was not the primary determinant for the change in expression level. The modified ng3-NEXT tag may be applied to increase the production yields of various recombinant proteins.
Initially, we isolated the caffeic acid O-methyltransferase (COMT) gene from Miscanthus sinensis (accession number HM062766.1). Next, we produced transgenic tobacco plants with down-regulated COMT gene expression to study its control of total phenol and lignin content and to perform morphological analysis. These transgenic plants were found to have reduced PAL and ascorbate peroxidases expression, which are related to the phenylpropanoid pathway and antioxidant activity. The MsCOMT-down-regulated plants had decreased total lignin in the leaves and stem compared with control plants. Reduced flavonol concentrations were confirmed in MsCOMT-down-regulated transgenic plants. We also observed a morphological difference, with reduced plant cell number in transgenic plants harboring antisense MsCOMT. The transgenic tobacco plants with down-regulated COMT gene expression demonstrate that COMT plays a crucial role related to controlling lignin and phenol content in plants. Also, COMT activity may be related to flavonoid production in the plant lignin pathway.
: This study was carried out to compare the characteristics of seed germination and the first stage of growth in Cynanchum wilfordii (Maxim.) by different light conditions such ass fluorescent light, dark and light emitting diode (LED). There was not much difference from the germination rate of C. wilfordii (Maxim.) in different light conditions for 10 days. The highest of germination rate occurred over 91.11 percentage by LED red condition at 26℃. Also mean germination velocity and promptness index were represented the highest results of 2.3 ea/day and 52.67 under red light, respectively. But mean germination time under both LED red and blue light was represented low data that it takes over three days for germinating of seed. Even though handling both LED red and blue lights, the germination uniformity was not constant. These results may help our understanding of variations in germination characteristics for C. wilfordii (Maxim.) seeds treated under different light conditions.
: This study is part of research to develop the technology for managing major medicinal crops after harvest. We studied the optimal germination conditions of Cynanchum wilfordii (Maxim.) Hemsl. The mean germination time (MGT) of C. wilfordii seeds was higher after soaking for 4 days after storage at 5℃ for 8 weeks, than with germination at 25 ℃ (3 days). However, the germinative energy (GE) decreased as the number of days soaking increased. The greatest germination rate (83.3 ± 8.8%) was at 25℃ with no soaking of seeds stored at −20℃ for 8 weeks. Based on these results, we characterized the germination conditions of a major medicinal crop.
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