Inducing Effect of Dihydroartemisinic Acid in the Biosynthesis of Artemisinins with Cultured Cells of Artemisia annua

Artemisinin has been used in the production of “artemisinin combination therapies” for the treatment of malaria. Feeding of precursors has been proven to be one of the most effective methods to enhance artemisinin production in plant cultured cells. At the current paper, the biosynthesis of artemisinin (ART) and its four analogs from dihydroartemisinic acid (DHAA) in suspension-cultured cells of Artemisia annua were investigated. ARTs were detected by HPLC/GC-MS and isolated by various chromatography methods. The structures of four DHAA metabolites, namely, dihydro-epi-deoxyarteannuin B, arteannuin I, arteannuin K, and 3-β-hydroxy-dihydro-epi-deoxyarteannuin B, were elucidated by physicochemical and spectroscopic analyses. The correlation between gene expression and ART content was investigated. The results of RT-PCR showed that DHAA could up-regulate expression of amorpha-4,11-diene synthase gene (ADS), amorpha-4,11-diene C-12 oxidase gene (CYP71AV1), and farnesyl diphosphate synthase gene (FPS) (3.19-, 7.21-, and 2.04-fold higher than those of control group, resp.), which indicated that biosynthesis processes from DHAA to ART were enzyme-mediated

Artemisinin biosynthesis and its regulatory enzymes: Progress and perspective

Artemisinin is an endoperoxidized sesquiterpene from the Chinese medicinal plant Artemisia annua, used as an effective anti-malarial drug. Its biosynthesis pathway has been investigated for many years for scientific interest and for potential manufacturing applications to fulfill the market demand. A number of regulatory enzymes of its biosynthesis process, including amorpha-4,11-diene synthase, CYP71AV1 and cytochrome P450 reductase, have been obtained and utilized to increase the content of artemisinin. However, a large knowledge gap still exists, and certain points of controversy have stirred debates within the field. In this review, the progress and perspective of artemisinin biosynthesis and its regulating enzymes are described

Recollements induced by good (co)silting dg-modules

summary:Let $U$ be a dg-$A$-module, $B$ the endomorphism dg-algebra of $U$. We know that if $U$ is a good silting object, then there exist a dg-algebra $C$ and a recollement among the derived categories ${\mathbf D}(C,d)$ of $C$, ${\mathbf D}(B,d)$ of $B$ and ${\mathbf D}(A,d)$ of $A$. We investigate the condition under which the induced dg-algebra $C$ is weak nonpositive. In order to deal with both silting and cosilting dg-modules consistently, the notion of weak silting dg-modules is introduced. Thus, similar results for good cosilting dg-modules are obtained. Finally, some applications are given related to good 2-term silting complexes, good tilting complexes and modules.\looseness -

Low temperature heat capacity study of Zn, Cd and Mn based coordination compounds synthesized using phenanthroline and halogenated benzoic acid

Four Zn, Cd and Mn based 1,10-phenanthroline and halogenated benzoic acid coordination compounds, formulated as Zn2(II)(H2O)(3)(phen)(SO4)center dot H2O (1, phen = 1,10-phenanthroline), Zn-II(Phen)(L-2)(2)(H2O) (2, L-2 = 2-chloro-4-fluorobenzoic acid), Mn-IV(phen)(L-1)(4) (3, L-1 = 2-Chloro-4,5-difluorobenzoic acid) and Cd-II(phen)(2)(NO3)(2) (4), were successfully synthesized and structurally characterized. The low temperature heat capacities of these four compounds were further investigated using a Physical Property Measurement System calorimetric method. The experimental heat capacities were fitted to a series of theoretical and empirical heat capacity models, and the corresponding thermodynamic functions were calculated in the temperature range from (0 to 300) K based on these models and fitting parameters. The low temperature fits indicated that compound 1 can be modeled using only lattice heat capacity contribution, compound 3 modeled using lattice and A(.2) term or Schottky heat capacity contributions, and compound 2 and 4 modeled using contributions from lattice, vacancies and one-dimensional phonons with a finite energy onset or gap

Phantom study of a self-shielded X-ray bone age assessment instrument against scattered radiation in children

Hand-wrist radiography is the most common and accurate method for evaluating children's bone age. To reduce the scattered radiation of radiosensitive organs in bone age assessment, we designed a small X-ray instrument with radioprotection function by adding metal enclosure for X-ray shielding. We used a phantom operator to compare the scattered radiation doses received by sensitive organs under three different protection scenarios (proposed instrument, radiation personal protective equipment, no protection). The proposed instrument showed greater reduction in the mean dose of a single exposure compared with radiation personal protective equipment especially on the left side which was proximal to the X-ray machine (≥80.0% in eye and thyroid,  ≥99.9% in breast and gonad). The proposed instrument provides a new pathway towards more convenient and efficient radioprotection. [Abstract copyright: © 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.