摘要：
As the first nucleoside antibiotic discovered in fungi, cordycepin, with its various biological activities, has wide applications. At present, cordycepin is mainly obtained from the natural fruiting bodies of Cordyceps militaris. However, due to long production periods, low yields, and low extraction efficiency, harvesting cordycepin from natural C. militaris is not ideal, making it difficult to meet market demands. In this study, an engineered Yarrowia lipolytica YlCor-18 strain, constructed by combining metabolic engineering strategies, achieved efficient de novo cordycepin production from glucose. First, the cordycepin biosynthetic pathway derived from C. militaris was introduced into Y. lipolytica. Furthermore, metabolic engineering strategies including promoter, protein, adenosine triphosphate, and precursor engineering were combined to enhance the synthetic ability of engineered strains of cordycepin. Fermentation conditions were also optimized, after which, the production titer and yields of cordycepin in the engineered strain YlCor-18 under fed-batch fermentation were improved to 4362.54 mg/L and 213.85 mg/g, respectively, after 168 h. This study demonstrates the potential of Y. lipolytica as a cell factory for cordycepin synthesis, which will serve as the model for the green biomanufacturing of other nucleoside antibiotics using artificial cell factories.
摘要：
Sesquiterpene lactone artemisinin is one of the main agents used to treat malaria. Artemisinin is produced in the glandular secretory trichomes (GSTs) of Artemisia annua. The plant hormones and metabolic pathways regulate the artemisinin content of A. annua. It was possible to examine the functions of auxin, an important plant hormone, in the development of GSTs in A. annua by enhancing the expression of iaaM, which encodes a tryptophan monooxygenase involved in the biosynthesis of auxin. Additionally, the effects of co-overexpression of aldehyde dehydrogenase 1 (ALDH1), P450 monooxygenase (CYP71AV1), and iaaM on the density, length, and width of GSTs and the contents of artemisinin were further investigated. Results indicated that overexpression of iaaM might increase the density, length, and width of GSTs by enhancing auxin biosynthesis. This study also proved the key regulatory role of ALDH1 in the biosynthesis of artemisinin. Moreover, co-overexpression of ALDH1, CYP71AV1, and iaaM successfully increased the density, length, and width of GSTs and improved the artemisinin content in A. annua. Therefore, we established a theoretical basis for modifying artemisinin accumulation in this study by regulating the expression of auxin and artemisinin synthesis-related genes using a metabolic engineering method.
通讯机构：
[Guangfu Feng; Jun Fang] S;School of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China<&wdkj&>School of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
通讯机构：
[Xiangyang Lu; Yun Tian] C;College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
关键词：
Cordycepin;Microbial sources;De novo biosynthesis;Metabolic engineering;Synthetic biology
摘要：
Background: Cordycepin is one of the nucleoside compounds with various nutraceutical and health-promoting functions, which makes it widely used in nutraceutical and pharmaceutical fields. Traditionally, cordycepin is mainly extracted from the natural fruiting bodies of Cordyceps spp.. However, the collection of natural Cordyceps willlead to the depletion of wild resources and the decline of biodiversity, as well as damage to the local fragile ecological environment.Scope and approach: This review provides the microbial resources of cordycepin and introduces the relationship between key metabolic pathways, transcription factors, and cordycepin biosynthesis in artificial cultured cordycepin-producing strains. In addition, the methods of strain improvement and genetic engineering to in-crease cordycepin production were reviewed, and the possibility of using synthetic biology to construct cell factories to increase cordycepin production was discussed.Key findings and conclusions: The analysis of the cordycepin biosynthesis pathway in fungi is of great guiding significance for the improvement of cordycepin production capacity. The construction of cell factories using synthetic biology and systematic metabolic engineering can be used as a green and energy-saving alternative method for the industrial production of cordycepin.
关键词：
aquatic plant;eutrophication;plant traitnetwork;littoral zone
摘要：
Our study elucidates how eutrophicationpromotes aquaticplant invasion based on 28 plant traits and highlights the importanceof mitigating eutrophication to combat plant invasion. Eutrophication and exotic species invasion are key driversof theglobal loss of biodiversity and ecosystem functions in lakes. We selectedtwo exotic plants (Alternanthera philoxeroides and Myriophyllum aquaticum) and twonative plants (Myriophyllum spicatum and Vallisneria spinulosa) to elucidatethe effect of eutrophication on exotic plant invasiveness. We foundthat (1) elevated nutrient favored invasion of exotic species andinhibited growth of native plants. Species combinations and plantdensities of native plants had limited effects on the resistance toinvasion of the exotics. (2) A. philoxeroides featured the tightest connectivity among traits, which is consistentwith its high competitive ability. Although eutrophication causedphysiological stress to A. philoxeroides, it could effectively regulate enzyme activity and alleviate thestress. (3) M. aquaticum possessedstrong tolerance to habitat disturbance and was highly disruptiveto the surrounding plants. Eutrophication will exacerbate the adverseeffects of M. aquaticum on the littoralecosystem. (4) Nutrient enrichment reduced the biomass and relativegrowth rates of V. spinulosa and loweredphenolics and starch contents of M. spicatum, thereby making them more susceptible to habitat fluctuations. Overall,our study highlights how eutrophication alters the invasiveness ofexotic plants and the resistance of native plants in the littoralzone, which is of relevance in a world with intensified human activities.
通讯机构：
[Bo Yang; Jun Fang] C;College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
关键词：
Bioconcentration and translocation factors;Co-occurrence network;Muti-metal(loid)s contamination;Phytoremediation;Predictive functional genes;Rhizospheric bacterial community
摘要：
Phytoremediation technology is an important approach applied to heavy metal remediation, and how to improve its remediation efficiency is the key. In this study, we compared the rhizospheric bacterial communities and metals contents in Miscanthus floridulus (M. floridulus) of four towns, including Huayuan Town (HY), Longtan Town (LT), Maoer Village (ME), and Minle Town (ML) around the lead-zinc mining area in Huayuan County, China. The roles of rhizospheric bacterial communities in assisting the phytoremediation of M. floridulus were explored. It was found that the compositions of the rhizospheric bacterial community of M. floridulus differed in four regions, but majority of them were heavy metal-resistant bacteria that could promote plant growth. Results of bioconcentration factors showed the enrichment of Cu, Zn, and Pb by M. floridulus in these four regions were significantly different. The Zn enrichment capacity of ML was the strongest for Cu and stronger than LT and ME for Pb. The enrichment capacity of LT and ML was stronger than HY and ME. These bacteria may influence the different heavy metals uptake of M. floridulus by altering the soil physiochemical properties (e.g., soil peroxidase, pH and moisture content). In addition, co-occurrence network analysis also showed that LT and ML had higher network stability and complexity than HY and ME. Functional prediction analysis of the rhizospheric bacterial community showed that genes related to protein synthesis (e.g., zinc-binding alcohol dehydrogenase/oxidoreductase, Dtx R family transcriptional regulators and ACC deaminase) also contributed to phytoremediation in various ways. This study provides theoretical guidance for selecting suitable microorganisms to assist in the phytoremediation of heavy metals.
关键词：
host immunity;intestinal microorganisms;metal metabolism;trace metal elements
摘要：
Trace metal elements, such as iron, copper, manganese, and zinc, are essential nutrients for biological processes. Although their intake demand is low, they play a crucial role in cell homeostasis as the cofactors of various enzymes. Symbiotic intestinal microorganisms compete with their host for the use of trace metal elements. Moreover, the metabolic processes of trace metal elements in the host and microorganisms affect the organism’s health. Supplementation or the lack of trace metal elements in the host can change the intestinal microbial community structure and function. Functional changes in symbiotic microorganisms can affect the host’s metabolism of trace metal elements. In this review, we discuss the absorption and transport processes of trace metal elements in the host and symbiotic microorganisms and the effects of dynamic changes in the levels of trace metal elements on the intestinal microbial community structure. We also highlight the participation of trace metal elements as enzyme cofactors in the host immune process. Our findings indicate that the host uses metal nutrition immunity or metal poisoning to resist pathogens and improve immunity.
摘要：
In recent years, the accelerated development of G-quadruplexes and hydrogels has driven the development of intelligent biomaterials. Based on the excellent biocompatibility and special biological functions of G-quadruplexes, and the hydrophilicity, high-water retention, high water content, flexibility and excellent biodegradability of hydrogels, G-quadruplex hydrogels are widely used in various fields by combining the dual advantages of G-quadruplexes and hydrogels. Here, we provide a systematic and comprehensive classification of G-quadruplex hydrogels in terms of preparation strategies and applications. This paper reveals how G-quadruplex hydrogels skillfully utilize the special biological functions of G-quadruplexes and the skeleton structure of hydrogels, and expounds its applications in the fields of biomedicine, biocatalysis, biosensing and biomaterials. In addition, we deeply analyze the challenges in preparation, applications, stability and safety of G-quadruplex hydrogels, as well as potential future development directions.
