Construction of a food-grade expression vector for application to lactic acid bacteria（LAB） is of importance for dairy fermentation system. An α-galactosidase（aga） gene encoding an enzyme degrading melibiose was ...Construction of a food-grade expression vector for application to lactic acid bacteria（LAB） is of importance for dairy fermentation system. An α-galactosidase（aga） gene encoding an enzyme degrading melibiose was amplified by PCR from the plasmid p RAF800 of Lactococcus lactis NZ9000. The aga gene was introduced into pMG36 e to substitute the p rimary antibiotic selectable marker of pMG36 e, resulting in construction of a new food-grade expression vector pMG36-aga. To testify the expression efficiency of exogenous gene in pMG36-aga, a 1.5 kb long α-amylase（amy） gene from Ba cillus li cheniformis was cloned by PCR and introduced into the plasmid pMG36-aga. The resultant plasimd pMG36-aga-amy was transformed into L. lactis ML23 by electroporation. The positive clones were selected with the medium containing melibiose as the sole carbon source. Th e selection efficiency of aga was 8.71×103 CFU with a standard deviation of 9.1×102 CFU ？g-1 DNA of pMG36-aga. Furthermore, the SDS-PAGE analysis showed that the pMG36-aga-amy expressed a 56.4 kDa protein which was the same as the putati ve molecular weight of α-amylase. The starch plate assay also indicated that L. lactis ML23 displayed high activity of α-amylase by expressing of amy gene of pMG36-aga-amy.展开更多
The study investigated the relationship among remittances,financial development and economic growth in a panel of 20 sub-Saharan African countries over the period of 2000 and 2015.The study used both Pooled Mean Group...The study investigated the relationship among remittances,financial development and economic growth in a panel of 20 sub-Saharan African countries over the period of 2000 and 2015.The study used both Pooled Mean Group and Mean Group/ARDL estimations with panel unit root and cointegration tests.After establishing cointegration,remittances and financial development were found to have positive effects on economic growth both in the short and the long run.The interactive term showed that financial development acted as a substitute in the remittances-growth relationship.Finally,unidirectional causal relationships were found to exist from GDP to remittances and from financial development to GDP.However,no causality existed between remittances and financial development in the SSA countries.展开更多
Dear Editor,Plant mitochondria are essential organelles of plant cells and play crucial roles in oxidative phosphorylation and diverse metabolic processes(Wang et al.,2024).Mitochondria have an endosymbiotic origin,li...Dear Editor,Plant mitochondria are essential organelles of plant cells and play crucial roles in oxidative phosphorylation and diverse metabolic processes(Wang et al.,2024).Mitochondria have an endosymbiotic origin,likely from a proteobacterial lineage that branched off before the divergence of known alphaproteobacterial groups(Martijn et al.,2018),and contain their own genetic materials,known as plant mitochondrial genomes(PMGs).PMGs exhibit unique features that may result from mechanisms different from those of nuclei and plastids,such as DNA repair(Chevigny et al.,2020),mRNA splicing(Novikova and Belfort.2017;Guo et al.,2020),transcription regulation,and foreign sequence integration.Recent advances in genome editing technologies have facilitated targeted modifications of PMGs,enabling the functional characterization of mitochondrial genes and the generation of desirable phenotypes(Forner et al.,2023;Xu et al.,2024).Accurate annotations of PMGs are a prerequisite for basic and applied research on mitochondria,such as studies of PMG evolution or targeted breeding of new crop varieties by PMG engineering.展开更多
基金supported by the National High-Tech R&D Program of China (863 Program, 2006AA10Z317)
文摘Construction of a food-grade expression vector for application to lactic acid bacteria（LAB） is of importance for dairy fermentation system. An α-galactosidase（aga） gene encoding an enzyme degrading melibiose was amplified by PCR from the plasmid p RAF800 of Lactococcus lactis NZ9000. The aga gene was introduced into pMG36 e to substitute the p rimary antibiotic selectable marker of pMG36 e, resulting in construction of a new food-grade expression vector pMG36-aga. To testify the expression efficiency of exogenous gene in pMG36-aga, a 1.5 kb long α-amylase（amy） gene from Ba cillus li cheniformis was cloned by PCR and introduced into the plasmid pMG36-aga. The resultant plasimd pMG36-aga-amy was transformed into L. lactis ML23 by electroporation. The positive clones were selected with the medium containing melibiose as the sole carbon source. Th e selection efficiency of aga was 8.71×103 CFU with a standard deviation of 9.1×102 CFU ？g-1 DNA of pMG36-aga. Furthermore, the SDS-PAGE analysis showed that the pMG36-aga-amy expressed a 56.4 kDa protein which was the same as the putati ve molecular weight of α-amylase. The starch plate assay also indicated that L. lactis ML23 displayed high activity of α-amylase by expressing of amy gene of pMG36-aga-amy.
文摘The study investigated the relationship among remittances,financial development and economic growth in a panel of 20 sub-Saharan African countries over the period of 2000 and 2015.The study used both Pooled Mean Group and Mean Group/ARDL estimations with panel unit root and cointegration tests.After establishing cointegration,remittances and financial development were found to have positive effects on economic growth both in the short and the long run.The interactive term showed that financial development acted as a substitute in the remittances-growth relationship.Finally,unidirectional causal relationships were found to exist from GDP to remittances and from financial development to GDP.However,no causality existed between remittances and financial development in the SSA countries.
基金supported by the CAMS Innovation Fund for Medical Sciences(CIFMS)(2021-I2M-1-022)the National Science&Technology Fundamental Resources Investigation Program of China(2018FY100705)the Provincial Special Project for Construction of Innovation Demonstration Area at Chenzhou City under National Sustainable Development Plan(2023sfq04).
文摘Dear Editor,Plant mitochondria are essential organelles of plant cells and play crucial roles in oxidative phosphorylation and diverse metabolic processes(Wang et al.,2024).Mitochondria have an endosymbiotic origin,likely from a proteobacterial lineage that branched off before the divergence of known alphaproteobacterial groups(Martijn et al.,2018),and contain their own genetic materials,known as plant mitochondrial genomes(PMGs).PMGs exhibit unique features that may result from mechanisms different from those of nuclei and plastids,such as DNA repair(Chevigny et al.,2020),mRNA splicing(Novikova and Belfort.2017;Guo et al.,2020),transcription regulation,and foreign sequence integration.Recent advances in genome editing technologies have facilitated targeted modifications of PMGs,enabling the functional characterization of mitochondrial genes and the generation of desirable phenotypes(Forner et al.,2023;Xu et al.,2024).Accurate annotations of PMGs are a prerequisite for basic and applied research on mitochondria,such as studies of PMG evolution or targeted breeding of new crop varieties by PMG engineering.
