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Enhanced production of ergothioneine in Aspergillus oryzae

Wang Lihong,Tian Xueqin,Xue Pinghong,Deng Yunhong,Gao Rui,Hu Zhihong

Ergothioneine (EGT) is a rare amino acid with potent antioxidant and anti-inflammatory properties, with a wide range of applications in food, cosmetics, and medicine. In the present study, Aspergillus oryzae , a common edible fungus, was engineered as an optimal host for EGT production. Moreover, two endogenous genes involved in EGT biosynthesis were characterized. The homolog AoEgt1 was shown to be localized in the vacuoles, whereas the homolog AoEgt2 was found in the peroxisomes. Overexpression of EGT biosynthetic genes from different organisms enhanced EGT production, yielding 15.17 mg EGT/g of dry weight. Using glucose as the carbon source and supplementing methionine (Met) as a precursor further increased EGT production to 20.03 mg EGT/g of dry weight, constituting an eight-fold increase compared to the wild-type strain. This study discusses the successful construction of a high-yielding A. oryzae strain for EGT biosynthesis, providing a novel strategy for efficient EGT synthesis. Key points • Two newly described homologs, AoEgt1 and AoEgt2, were identified in A. oryzae. • AoEgt1 and AoEgt2 were found to contribute to EGT biosynthesis. • EGT production was significantly increased by overexpression of Egt1 and Egt2. • Glucose and Met supplementation in the medium increased EGT production.

Outstanding Reviewers for Sensors & Diagnostics in 2024

We would like to take this opportunity to thank all of Sensors & Diagnostics's reviewers for helping to preserve quality and integrity in chemical science literature. We would also like to highlight the Outstanding Reviewers for Sensors & Diagnostics in 2024.

Readdressing of Magnetoelectric Effect in Bulk BiFeO3

Xin Xin Shi,Xiao Qiang Liu,Xiang Ming Chen

After decades of study, BiFeO 3 is still the most promising single-phase multiferroic material due to its large polarization and high operating temperature, drawing much attention. As a typical type-I multiferroic material, the magnetoelectric coupling in BiFeO 3 is deemed to be weak due to the different origins of its ferroelectricity and magnetism. Here, the magnetoelectric effect in bulk BiFeO 3 is readdressed both theoretically and experimentally. Based on the Dzyaloshinsky–Moriya interaction scenario, the magnetoelectric effect in BiFeO 3 is actually strong, with a coupling energy of about 1.25 meV and a magnetism-coupled parasitic polarization comparable to that of the type-II multiferroics. However, such strong magnetoelectric coupling also causes the cycloidal spin structure, which inhibits the observation of linear magnetoelectric coupling in bulk BiFeO 3 . To resolve this contradiction, Sm-substitution is utilized to suppress the magnetoelectric effect and unlocks the weak ferromagnetism. At an optimized composition, such a weak ferromagnetic state can be switched back to the cycloidal state by an electric field, thus realizing electrical control of the magnetism. It has been argued that field-controlled phase transition is a promising path to colossal magnetoelectric effect. It is of pioneering significance for further investigations down this road.

Continuously tunable multistability in DNA replication networks

Zhong Rui,Fu Yanjie,Jiang Shubao,Wang Shan,Yue Liang,Tan Weihong

Multistable systems, ideally, could stabilize at any desired, switchable state within a continuous spectrum. However, conventional systems, constrained by signal-mediated mutual activation or inhibition, are limited to a finite set of discrete steady states. Here, we propose a rational framework for achieving continuously tunable multistability through reversible displacement reaction-mediated competition between positive autoregulatory DNA polymerization/nicking modules. This framework harnesses the chemical energy of dNTP hydrolysis to suppress spontaneous interconversion between modules for stabilizing at any target state along a continuous compositional gradient. With unparalleled tunability, the framework enables continuous, orthogonal state transitions and concentration-adaptive molecular memory in response to transient stimuli. Moreover, the single-stranded DNAs generated by polymerization/nicking reactions can be customized with predefined structures and functions, enabling continuously multistable control over downstream processes, e.g., biocatalysis and RNA transcription, while maintaining multistability. This framework establishes a versatile and robust platform for developing chemical and material systems with continuously tunable multistability.

Enhanced thermoelectric properties in Ag-rich AgSbSe2

Xiao-Cun Liu,Yan-Min Wang,Mei-Li Qi,Ming-Yan Pan

In this paper, we report remarkably improved thermoelectric properties of p-type Ag-rich AgSbSe 2 . Polycrystalline bulk samples of Ag 1+ x Sb 1- x Se 2 (x ​= ​0, 0.01, 0.02, 0.03) were prepared from high purity elements and densified by spark plasma sintering. The X-ray diffraction analysis indicates the formation of solid solution and Ag 2 Se second phase in Ag-rich samples. The existence of Ag 2 Se precipitates is further confirmed by differential scanning calorimetric measurements and scanning electron microscopy images. The increased carrier concentrations combined with the modified band structures lead to the enhanced power factor in Ag 1+ x Sb 1- x Se 2 . Ag 2 Se particles act as phonon scattering centres and reduce the lattice thermal conductivity. This, together with the increased power factor, further enhances the thermoelectric figure of merit ZT . The maximum ZT value at 673 ​K increases from 0.44 for pristine AgSbSe 2 to 1.02 for Ag 1.02 Sb 0.98 Se 2 , which is more than two times enhancement.

Multiphonon Process in Mn-Doped ZnO Nanowires

Jia-Min Lai,Muhammad Umair Farooq,Yu-Jia Sun,Ping-Heng Tan,Jun Zhang

The multiphonon process plays an essential role in understanding electron–phonon coupling, which significantly influences the optical and transport properties of solids. Multiphonon processes have been observed in many materials, but how to distinguish them directly by their spectral characteristics remains controversial. Here, we report high-order Raman scattering up to 10 orders and hot luminescence involving 11 orders of phonons in Mn-doped ZnO nanowires by selecting the excitation energy. Our results show that the intensity distribution of high-order Raman scattering obeys an exponential decrease as the order number increases, while hot luminescence is fitted with a Poisson distribution with a resonance factor. Their linewidth and frequency can be well explained by two different transition models. Our work provides a paradigm for understanding the multiphonon-involved decay process of an excited state and may inspire studies of the statistical characteristics of excited state decay.

Gas Generation Mechanism in Li-Metal Batteries

Huajun Zhao,Jun Wang,Huaiyu Shao,Kang Xu,Yonghong Deng

Gas generation induced by parasitic reactions in lithium-metal batteries (LMB) has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry, which occurs via the complex interplays among electrolytes, cathode, anode, and the decomposition species that travel across the cell. In this work, a novel in situ differential electrochemical mass spectrometry is constructed to differentiate the speciation and source of each gas product generated either during cycling or during storage in the presence of cathode chemistries of varying structure and nickel contents. It unambiguously excludes the trace moisture in electrolyte as the major source of hydrogen and convincingly identifies the layer-structured NCM cathode material as the source of instability that releases active oxygen from the lattice at high voltages when NCM experiences H2 → H3 phase transition, which in turn reacts with carbonate solvents, producing both CO 2 and proton at the cathode side. Such proton in solvated state travels across the cell and becomes the main source for hydrogen generated at the anode side. Mechanisms are proposed to account for these irreversible reactions, and two electrolyte additives based on phosphate structure are adopted to mitigate the gas generation based on the understanding of the above decomposition chemistries.

Fenpropathrin exposure induces neurotoxicity in zebrafish embryos

Yu Tingting,Xu Xiaowen,Mao Huiling,Han Xue,Liu Yulong,Zhang Hongying,Lai Jingli,Gu Jianfeng,Xia Mengling,Hu Chengyu,Li Dongming

Fenpropathrin has been a commonly used insecticide to control agricultural and household insects over a few decades. Up to now, fenpropathrin residue in soil and water has been often determined due to its widespread use, which poses serious threat to environment and aquatic organisms. The potential of fenpropathrin to affect aquatic lives is still poorly understood. In this study, we used zebrafish ( Danio rerio ) embryo as an experimental model system to evaluate the toxicity of fenpropathrin to the development of zebrafish nervous system. Zebrafish embryos were separately exposed to fenpropathrin at the dose of 0.016 mg/L, 0.032 mg/L, 0.064 mg/L, starting at 6 h post-fertilizationhpf (hpf) up to 96 hpf. The results showed that fenpropathrin exposure gives rise to physiological, behavioral, and neurodevelopmental impairments in zebrafish embryos, including enhanced acetylcholinesterase (AChE) activity, abnormal swimming behavior, karyopyknosis in brain cells, increased intercellular space, and uneven migration of neuron in brain area. In addition, the expressions of genes concerning neurodevelopment and neurotransmitter system were inhibited following fenpropathrin exposure. We also found that fenpropathrin exposure distinctly induced oxidative stress by increasing reactive oxygen species (ROS) generation and inhibiting the production of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). Expectedly, some apoptosis-associated genes were induced and the apoptosis appeared in the brain and heart cells of zebrafish embryos. Moreover, fenpropathrin exposure also inhibited the expressions of genes in Nrf2 signaling pathway, such as heme oxygenase-1 ( HO-1 ) and SOD . In summary, the results of this study indicate that oxidative stress-triggered apoptosis may be an underlying fundamental of fenpropathrin-induced neurotoxicity in zebrafish embryos.

Tunable replica symmetry breaking in random laser

Jiangying Xia,Xiaojuan Zhang,Kaiming Zhou,Lin Zhang,Erlei Wang,Wenyu Du,Jiajun Ma,Siqi Li,Kang Xie,Benli Yu,Junxi Zhang,Zhijia Hu

Replica symmetry breaking (RSB) has been widely recognized as a statistical analysis approach to understand the disorder and nonlinear interactions in complex systems ranging from atoms to the cosmic scale. However, it is challenging to analyze the nonlinear optical characteristics of random laser (RL) in disordered gain medium via RSB due to the lack of a general RSB-based statistical analysis framework. In this work, we report the tunable RSB in polymer fiber RL, where the effects of temperature and different structures on RSB are investigated experimentally and theoretically. It experimentally proves that RSB in RL is not robust, and disorder and temperature are responsible for tunable RSB in RL, which contributes to the improvement of the statistical analysis framework for investigating the optical principles of RL using RSB. And the finding of the tunable RSB allows to investigate the dynamical differences for various RL systems, which broadens the directions for the use of spin-glass theory to explore the physical mechanism of RL.

Berberine attenuates hyperalgesia in mice with adenomyosis

Zhu Bo,Chen Yumei,Guo Min,zhang Chenhui,Huang Lingxiao,Pan Qiangwei,Lin Tao,Lu Yiyi,Shen Xiaolu,Zhang Hongping

Purpose Adenomyosis is a common gynecological disease, but its pathogenesis and treatment options are not yet completely clear. This study aimed to investigate the analgesic effect of berberine on tamoxifen-induced neonatal mouse adenomyosis and its curative effects on the disease. Methods The mouse adenomyosis model was established in neonatal female mice via oral administration of tamoxifen suspended solution. Adenomyosis mice were given berberine by intraperitoneal injection with the dosage of 5, 10, and 20 mg/kg body weight, respectively, at 17 weeks after birth. The pain sensation of the mice was evaluated by hotplate and tail-flick tests. The mRNA levels of gene expression were detected by RT-qPCR. The protein expression was analyzed by ELISA and Western blot. Results Berberine reduced the uterine weight, suppressed the myometrial infiltration of ectopic endometrium, improved the hotplate and tail-flick latency of the adenomyosis mice. Mechanistically, berberine downregulated the expression of genes related to pain and inflammation, such as TRPV1, COX-2, VEGF and OTR, impaired the inflammatory response at the DRG site, and inhibited the expression of TLR4 in DRG and uterine tissues. Conclusions Berberine attenuates hyperalgesia and exhibits analgesic and therapeutic effects on adenomyosis mice.

Selective biosynthesis of retinol in S. cerevisiae

Hu Qiongyue,Zhang Tanglei,Yu Hongwei,Ye Lidan

The vitamin A component retinol has become an increasingly sought-after cosmetic ingredient. In previous efforts for microbial biosynthesis of vitamin A, a mixture of retinoids was produced. In order to efficiently produce retinol at high purity, the precursor and NADPH supply was first enhanced to improve retinoids accumulation in the S. cerevisiae strain constructed from a β-carotene producer by introducing β-carotene 15,15ʹ-dioxygenase, following by screening of heterologous and endogenous oxidoreductases for retinal reduction. Env9 was found as an endogenous retinal reductase and its activity was verified in vitro. By co-expressing Env9 with the E. coli ybbO , as much as 443.43 mg/L of retinol was produced at 98.76% purity in bi-phasic shake-flask culture when the antioxidant butylated hydroxytoluene was added to prevent retinoids degradation. The retinol titer reached 2479.34 mg/L in fed-batch fermentation. The success in selective biosynthesis of retinol would lay a solid foundation for its biotechnological production. Graphical Abstract

Coalescence law of microdroplet swarms in microchannels

Chenghao Gao,Sida Ling,Zhuo Chen,Yundong Wang,Jianhong Xu

Droplet microfluidic technology refers to the technique of preparing and controlling microscale monodisperse droplets by shear force and interfacial tension of two immiscible phases accurately, which has a wide range of applications in biomedicine, chemical reaction enhancement, nanoparticle preparation, and other fields due to its efficient mass and heat transfer, easy manipulation, rapid response, and high throughput. In the application of droplet microfluidic technology, coalescence often occurs due to the structural complexity of microchannels, which limits the practical application performance. The mechanism of droplet coalescence has been widely studied in conventional reactors, among which the liquid film drainage theory is the most widely accepted. To achieve accurate control of the droplet coalescence process, there have been many studies on droplet coalescence in microchannels. A variety of microchannel structures have been proposed and the mechanism and influencing factors of double droplets coalescence have been explored. However, most of the existing studies on coalescence are based on cross structures, mainly studying the coalescence of double droplets in confined systems. There is still a lack of research on the coalescence process of droplet swarms, which is more widespread in practical applications. Therefore, this work used the rectangular expansion structure to realize the droplet coalescence and explored the effects of two-phase flow rate, continuous phase viscosity, surfactant concentration, and the size of expanding channel on the droplet coalescence behavior. The coalescence types, probabilities, and size distributions of microdroplet swarms under different factors were summarized. The time distribution of liquid film drainage in the droplet coalescence process and the influence of various factors on it were further analyzed based on the liquid film drainage theory.