Artiles
Review
28 July 2023Challenging Post-translational Modifications in the Cell-free Protein Synthesis System
Post-translational modifications (PTMs) represent a cornerstone in the complexity of the proteome, significantly contributing to diversifying protein structure and function. PTMs can considerably influence protein function, stability, localization, and interactions with other molecules. Therefore, it is important when choosing a protein expression system to ensure the precise incorporation of PTMs during protein synthesis, which is paramount for producing biologically active proteins. The cell-free protein synthesis (CFPS) system has emerged as a powerful protein synthesis platform and research toolkit in synthetic biology. The open nature of the system allows the reaction environment to be tailored to any protein of interest to promote specific PTMs, thus allowing for the production of a protein with desired modifications. This review presents various PTMs achieved in the CFPS systems, providing insights into current challenges, successes, and future prospects.
Review
24 July 2023Creating Shape Memory Polymers from Biobased Resources
Developing polymer materials from biomass is a promising pathway to address serious environmental and resource issues. To date, a series of biobased general polymer materials have been successfully industrialized. However, exploring highly valuable functional polymers and intelligent polymer materials from biomass, such as shape memory polymers (SMPs) and self-healing materials, is still a great challenge. The present review intends to bridge a sustainable pathway for the creation of SMPs from biobased resources. Thus, we first recall some backgrounds of the design principle of SMPs and highlight the biobased monomers or building blocks for SMPs, and then we focus on the main varieties of biobased SMPs to clarify their fabricating approaches, functionalizing strategies, new manufacturing methods and the application potential.
Article
20 July 2023Fine-scale Genetic Structure of Geographically Distinct Patrilineal Lineages Delineates Southward Migration Routes for Han Chinese
The Han Chinese (HAN) represent the world’s largest ethnic group, and their genetic structure has been the focus of numerous studies. Yet previous studies failed to draw out finer population stratification of patrilineal HAN, due to limitations in sample size and genetic marker density. This essay employs a Y-haplogroup frequency dataset from virtually whole China aiming to draw out a detailed genetic structure of the patrilineal HAN. We provide an overview of the Y chromosome haplogroup distributions, and find that the patrilineal HAN can be divided into five geographic subgroups. Analysis of Molecular Variance (AMOVA) provided further support for the five-substructure model. By comparing patrilineal and matrilineal descent, we revealed stronger geographical aggregation for patrilineal HAN. Moreover, populations with patrilineal descent showed lower levels of haplogroup diversity (HD) compared to those with matrilineal descent, suggesting potential population bottleneck of patrilineal HAN. The larger HD among northern patrilines verified historical migration of HAN from north to south, which validated by neighbor joining tree (NJ-tree). Overall, we speculate the southward migration routes for Han Chinese, and the HAN south of the Nanling Mountains may have entered via the middle reaches of the Yangtze River, rather than via eastern coastal provinces.
Article
19 July 2023Hydroxybenzoic Acid Production Using Metabolically Engineered Corynebacterium glutamicum
Hydroxybenzoic acids (HBAs), including 4-HBA, 3-HBA, and 2-HBA, are valuable platform chemicals for production of commodity materials and fine chemicals. Herein, we employed metabolic engineering techniques to enhance the production of these HBAs in Corynebacterium glutamicum ATCC 13032. Our approach augmented the shikimate pathway and eliminated genes associated with HBA degradation, particularly phenol 2-monooxygenase encoded by cg2966. Increased titers of 3-HBA and 4-HBA were achieved via selection of suitable promoters for 3-hydroxybenzoate synthase and chorismate pyruvate lyase. A tac-M1 promoter was suitable for chorismate pyruvate lyase expression and 8.3 g/L of 4-HBA production was achieved. Efficient production of 2-HBA was enabled by maintaining a balanced expression of isochorismate synthase and isochorismate pyruvate lyase. Consequently, strains KSD5-tacM1-H and KSD5-J2-PE exhibited production levels of 19.2 g/L of 3-HBA and 12.9 g/L of 2-HBA, respectively, using 1 L jar fermenter containing 80 g/L of glucose. Therefore, this engineered strain platform holds significant potential for production of other valuable products derived from chorismate.
Perspective
06 July 2023An Extremely Long Span of the Sun-Earth Pattern in the History of China
Chinese people believe that they are descendants of the prehistory Emperors Yan and Huang, while Yan (hot/red) and Huang (yellow) are the colors of the sun and earth. In the Dahecun style of Yangshao Culture archaeological culture of the legendary Yan and Huang’s period, the patterns of the sun and earth were frequently painted on the religious potteries, implying that the paired symbols might refer to the two emperors. However, the same paired pattern appeared in Shangshan Culture much earlier than Yangshao, indicating that the worship of Sun-Earth might have a quite long history prior to the two emperors. The pattern was inherited in the populations of China till today. The Jade Bi-Cong group of late Neolithic and early Bronze Age China also showed the same meanings and shapes. We found that the Sun-Earth pattern was quite common on the traditional brocade belts woven in the countryside around Shanghai. The origin of the sun shape was easy to understand, while that of the earth shape, a cross with or without an outline square, was hard to trace. Recent archaeological discovery in Shangshan Culture of a kind of yellow pyramid stone provided a new clue to the origin of earth symbol.
Article
05 July 2023Photocatalytic Efficiency of Suspended and Immobilized TiO2 P25 for Removing Myclobutanil, Penconazole and Their Commercial Formulations
Fungicide application in viticulture is a major source of surface and groundwater contamination. It is therefore essential to find solutions to stop this environmental pollution. Heterogeneous photocatalysis is an advanced oxidation method for the degradation and mineralization of organic pollutants in water. TiO2 P25 photocatalyst in suspension has been used for removing the fungicides Myclobutanil and Penconazol, and their respective commercial formulations Systhane and Topas, in contaminated water. The apparent kinetic constants kapp of fungicides removal over 30 min batch treatment was higher for a mixture of pure molecules of Myclobutanil and Penconazol than for a mixture of their commercial formulations (17.5 × 10−3 by comparison with 10.3 × 10−3 min−1 for Myclobutanil, and 10.0 × 10−3 by comparison with 2.80 × 10−3 min−1 for Penconazol). TOC removal constants kTOC were similar for the two mixtures, due to the presence of mineral and organic additives in the commercial formulations. To easily recover the photocatalyst after fungicide removal, TiO2 P25 has been supported on β-SiC foam. Fungicides degradation was lower with supported photocatalysts than with the suspension of photocatalyst nanoparticles (NPs) because of a lower concentration of active sites on the supported photocatalyst than in the catalyst suspension. However, catalyst recovery and reuse after fungicide removal is obviously easier with TiO2/β-SiC material than with a suspension of TiO2 which requires long and expensive filtration operations.
Article
14 June 2023Spatio-temporal Evolution and Influencing Factors of Farmland Circulation Price at the County Level in China
Farmland circulation is an important way to achieve moderate scale operation to ensure food security. Based on the spatial analysis and spatial econometric model, this paper studies the spatial-temporal evolution and influencing factors of cultivated land transfer price at the county level in China from 2015 to 2020. The results revealed the following: (1) the circulation price of farmland generally shows paddy field > irrigated land > dry land > other cultivated land. The farmland circulation price in Huang-Huai-Hai Plain is always the highest, whereas that in Qinghai–Tibet Plateau is always the lowest. (2) The spatial pattern of farmland circulation price is high in the south and low in the north, presenting an inverted U-shaped structure from east to west in 2015, and high in the east and low in the west, presenting an inverted U-shaped structure from north to south in 2020. Moreover, the spatial agglomeration was enhanced. (3) With the development of land market and urbanization, the restriction of natural factors of cultivated land on the farmland circulation price weakens, while the socio-economic attribute of cultivated land constantly strengthens. Based on the results, this paper puts forward some suggestions to prevent the overcapitalization of land.
Perspective
12 June 2023Encounter between Present Female Characters and Neolithic Inscribed Symbols Prior to Oracle-bone Inscriptions
Inscribed symbols of Neolithic Age were sometimes suspected to be initial writing prior to developed writing system. The earliest developed writing system in China was Oracle-bone inscriptions (OBIs) of Bronze Age and researchers have long sought its predecessor. Here, we reported that two continuous symbols on a stone ax of Neolithic Liangzhu culture found their identical duplicates in a unique writing system on brocade belts woven by present women in Shanghai suburb. Women in this group duplicated the hereditary text for weddings only once each generation in the past, and they can still interpret these two characters, implying that the two identical Liangzhu symbols may have the similar meanings. The meanings and patterns are both similar to those in OBIs, suggesting that Liangzhu symbols might be one of the predecessors of OBIs. Integrating philology, genetics, linguistics, and folklore, we discussed that special small population may inherit both the genetic structure and convert culture for extremely long time, such as this population in southern Shanghai.
Article
01 June 2023Transparent, Hydrolysable and Flame Retarded Bio-based Epoxy Resins via Catalyst-free Polymerization of Triglycidyl Isocyanurate and Aliphatic Diacids
In this study, transparent and hydrolysable intrinsic flame retarded epoxy resins were synthesized successfully by melting polymerization without any catalyst, simply from bio-based triglycidyl isocyanurate and aliphatic diacids. Due to the possibility of transesterification along with the ring-opening reaction, the most suitable feed ratio of [COOH]/[epoxy] is found to be 60%. By changing the carbon number of diacid from 8 to 12, ER08-60, ER10-60 and ER12-60 were synthesized. The flame retardancy of ER08-60 is found to be excellent, with a UL-94 rating at V-0 and a LOI value at 27.6%. It is revealed from this study that upon heating isocyanurate ring decomposes first and CO2 released prevents the contact of materials with oxygen, thus preventing further combustion. The tensile strength and bending strength of ER08-60 can reach 86.6 MPa and 75.4 MPa, respectively. Additionally, all epoxy resins are able to hydrolyze quickly in both acid and alkaline solutions. It is worth to mention that these epoxy resins are transparent, with a transmittance of around 85%.
Article
31 May 2023Nitrogen-controlled Valorization of Xylose-derived Compounds by Metabolically Engineered Corynebacterium glutamicum
The implementation of bioprocesses in an economically feasible and industrial competitive manner requires the optimal allocation of resources for a balanced distribution between biomass formation and product synthesis. The decoupling of growth and production in two-stage bioprocesses, aiming to ensure sufficient growth before the onset of production, is particularly relevant when target products inhibit growth. In order to avoid expensive inducer molecules, continuing process monitoring, elaborate individual process optimization, and strain engineering, we developed and applied nitrogen deprivation-induced expression of genes for product biosynthesis. Two native nitrogen deprivation-inducible promoters were identified and shown to function for dynamic growth-decoupled gene expression or CRISPRi-mediated gene knockdown in C. glutamicum with superior induction factors than the standard IPTG-inducible Ptrc promoter. Valorization of xylose to produce either the sugar acid xylonic acid or the sugar alcohol xylitol from xylose as sole source of carbon and energy was demonstrated. Competitive titers of up to 34 g·L−1 xylonate and 13 g·L−1 xylitol were achieved in two-stage processes. We discussed that the transfer to bioprocesses with C. glutamicum using carbon sources other than xylose appears straightforward in particular regarding production of growth-inhibitory compounds by their growth-decoupled fermentative production.
