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Developing methylotrophic cell factories that can efficiently catalyze organic one-carbon (C1) feedstocks derived from electrocatalytic reduction of carbon dioxide into bio-based chemicals and biofuels is of strategic significance for building a carbon-neutral, sustainable economic and industrial system. With the rapid advancement of RNA sequencing technology and mass spectrometer analysis, researchers have used these quantitative microbiology methods extensively, especially isotope-based metabolic flux analysis, to study the metabolic processes initiating from C1 feedstocks in natural C1-utilizing bacteria and synthetic C1 bacteria. This paper reviews the use of advanced quantitative analysis in recent years to understand the metabolic network and basic principles in the metabolism of natural C1-utilizing bacteria grown on methane, methanol, or formate. The acquired knowledge serves as a guide to rewire the central methylotrophic metabolism of natural C1-utilizing bacteria to improve the carbon conversion efficiency, and to engineer non-C1-utilizing bacteria into synthetic strains that can use C1 feedstocks as the sole carbon and energy source. These progresses ultimately enhance the design and construction of highly efficient C1-based cell factories to synthesize diverse high value-added products. The integration of quantitative biology and synthetic biology will advance the iterative cycle of understand--design--build--testing--learning to enhance C1-based biomanufacturing in the future. [ABSTRACT FROM AUTHOR]

Fusarium head blight ( FHB) is a severe global wheat disease that may cause severe yield losses, especially during epidemic years. Transforming the regulatory genes in the metabolic pathways of disease resistance into wheat via transgenic methods is one way to improve resistance to FHB. Sc NPR1 ( Secale cereale- NPR1) , a regulatory gene for systemic acquired resistance ( SAR), was isolated from S. cereale cv Jingzhouheimai and transformed into the moderately FHB-susceptible wheat variety Ningmai 13. RT- PCR analysis indicated that the Sc NPR1 gene was stably expressed in transgenic plants. An evaluation of the resistance to FHB revealed that six Sc NPR1 transgenic lines ( NP1, NP2, NP3, NP4, NP5 and NP6) exhibited significantly higher FHB resistance than the wild-type wheat Ningmai 13 and the null-segregated plants. The expression of pathogenesis-related ( PR) genes after Fusarium graminearum inoculation was earlier or higher than those in the wild-type variety Ningmai 13. The high expression in the early stages of PR genes should account for the enhanced FHB resistance in the transgenic lines. Our results suggest that overexpression of Sc NPR1 could be used to improve FHB resistance in wheat. [ABSTRACT FROM AUTHOR]

Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression. [ABSTRACT FROM AUTHOR]

Studies of the extraction kinetics of cerium(IV) from H2SO4–HF solutions with Cyanex 923 in n-heptane have been carried out using a constant interfacial area cell with laminar flow. The experimental hydrodynamic conditions were chosen so that the contribution of diffusion to the measured rate of reaction was minimized. The data were analyzed in terms of pseudo-first order constants. The results were compared with those of the system without HF. It was concluded that the addition of HF reduces the activation energy for the forward rate from 46.2 to 36.5 kJ mol−1 while it has an opposite effect on the activation energy for the reverse process(the activation energy increased from 23.3 to 90.8 kJ mol−1). Thus, HF can accelerate the rate of cerium(IV) extraction. At the same time, the extraction rate is controlled by a mixed chemical reaction–diffusion rather than by a chemical reaction alone. A rate equation has also been obtained. [Copyright &y& Elsevier]

Phase behavior of the extraction system, Cyanex 923–heptane/H2SO4–H2O has been studied. The third phase appeared at different aqueous H2SO4 concentration with varying initial Cyanex 923 concentration and temperature affects its appearance. Almost all of H2SO4 and H2O are extracted into the middle phase. The H2SO4 concentration in the third phase increases with the increasing aqueous acid concentration (CH2SO4,b) while the water content first increases and then reaches a constant value at CH2SO4,b=11.3 mol l−1. In the region of CH2SO4,b higher than 5.2 mol l−1, the composition of the middle phase is only related to the equilibrium concentration of H2SO4 in the bottom phase. H2SO4 and H2O are transferred into the middle phase mainly by their coordination with Cyanex 923 when CH2SO4,b is less than 11.3 mol l−1. When CH2SO4,b is higher than 11.3 mol l−1, excess H2SO4 is solubilized into the polar layer of the aggregates. In the region considered, the extracted complex changes from C923 · H2SO4 to C923 · H2SO4 · H2O and then to C923 · (H2SO4)2 · H2O. [Copyright &y& Elsevier]