Two amino acids missing of MtrA resulted in increased erythromycin level and altered phenotypes in Saccharopolyspora erythraea.

The MtrA-MtrB two-component regulatory system is highly conserved in Actinobacteria and plays crucial roles in cell cycle progression, cell morphology, antibiotic resistance, and osmoprotection. Previously, we revealed that the MtrA protein of Saccharopolyspora erythraea E3 strain (a high erythromycin-producing strain) had a two amino acid (H197 and V198) deletion in the DNA recognition helices of the C-terminal domain compared to the wild type S. erythraea strain NRRL2338. Here, we identified mepA (encoding a membrane protein related to metalloendopeptidases) as an MtrA target gene, and found that deleting the two amino acids in MtrA (MtrAdel) resulted in the loss of its DNA-binding activity for the mepA gene. The mutant MtrAdel lost its regulatory activity and affected various physiological functions consistent with mtrA deletion, including increased erythromycin biosynthesis, enhanced antibiotic resistance, deregulated osmoprotection, and improved transport of substances. The introduction of the wild type mtrA gene into the S. erythraea E3 strain with the mtrAdel gene decreased the erythromycin yield by approximately 50%, confirming that MtrA repressed erythromycin production. These findings demonstrate that MtrA is an important pleiotropic regulator of erythromycin biosynthesis, antibiotic resistance, osmoprotection, and substance transport in S. erythraea and provide new insights for improving erythromycin production. Future studies linking the molecular effects of MtrA to these phenotypes will improve our understanding of the MtrA-MtrB two-component regulatory system in Actinobacteria.

Preparation of molecularly imprinted polymeric microspheres based on distillation-precipitation polymerization for an ultrasensitive electrochemical sensor.

A highly sensitive electrochemical sensor based on a carbon paste electrode (CPE) modified with molecularly imprinted polymeric microspheres (MIPMSs) was developed for the determination of bisphenol A (BPA). For the first time BPA-imprinted MIPMSs were prepared via distillation precipitation polymerization, and then the polymeric microspheres were involved in producing the MIPMS-modified CPE (MIPMS/CPE). The polymers obtained were observed via a scanning electron microscope and its dynamic and static adsorption performances were investigated. Cyclic voltammetry and electrochemical impedance spectroscopy were performed to study the preparation process and electrochemical behavior of the modified carbon paste electrodes with [Fe(CN)6]3-/4- ions acting as electrical indicators. Compared with the bulk MIP packed sensor, the MIPMS/CPE exhibits a higher sensing response and better reproducibility. The detection linear range for BPA is 1 × 10-11-1 × 10-7 M with a detection limit of 2.8 × 10-12 M (S/N = 3) under the optimal experimental conditions. Moreover, the MIPMS/CPE exhibited good selectivity and stability. The developed sensor can determine BPA in real samples including soil, milk and water rapidly and accurately after simple sample pretreatment.

An ultrasensitive and selective electrochemical sensor for determination of estrone 3-sulfate sodium salt based on molecularly imprinted polymer modified carbon paste electrode.

A highly sensitive and selective electrochemical sensor based on carbon paste electrode (CPE) modified with molecularly imprinted polymers (MIPs) has been developed for the determination of estrone 3-sulfate sodium salt (ESS). MIPs were prepared in polar medium via bulk polymerization and characterized by scanning electron microscopy and infrared spectroscopy. Cyclic voltammetry was performed to the study preparation process and binding behavior of the MIP-modified CPE (MIP/CPE) toward ESS. The conditions for preparing MIPs and MIP/CPE as well as ESS detection were optimized. Under the optimal experimental conditions, the detection linear range for ESS is 4 × 10-12 to 6 × 10-9 M with a limit of detection of 1.18 × 10-12 M (S/N = 3). In addition, the sensor exhibits high binding affinity toward ESS over its structural analogues with excellent repeatability and stability. The fabricated MIP/CPE was then successfully employed to detect ESS in pregnant mare urine (PMU) without any pretreatment, and the average recoveries were from 99.6 to 104.9% with relative standard deviation less than 3.0%. High-performance liquid chromatography was adopted as a reference to validate the established approach in detecting ESS and their results showed good agreement. The as-prepared sensor has high potential to be a decent tool for on-site determination of ESS in PMU in a fast and convenient manner. Graphical Abstract ᅟ.

The impact of financial development on enterprise green innovation under low carbon pilot city.

Low-carbon pilot city (LCPC) plays a pivotal role in stimulating green innovation among enterprises. However, relying solely on policy often proves less effective, necessitating support from financial development. Yet, current research frequently overlooks the impact of financial development on LCPC policy. Drawing on economic, management, and organizational psychology theories, we investigate the influence of the financial development level on enterprise green innovation in LCPC, utilizing data from listed companies between 2010 and 2018. The main finding is that LCPC facilitates institutional-level green innovation. Concurrently, financial development augments the effectiveness of LCPC policy, further expediting green innovation activities among enterprises in these pilot cities. Heterogeneity analyses reveal that financial development significantly promotes green innovation, particularly among state-owned enterprises, those with myopic management, non-high technology industries, and businesses in the southern region within LCPC. Mechanism tests identify enterprises' financing constraints and R&D investment levels as key pathways through which financial development fosters green economic development in LCPC. This study provides micro-level evidence from China elucidating the effects of environmental policies and offers practical implications for the low-carbon transformation of the manufacturing sector amid peak emissions and carbon-neutral targets. Additionally, it provides valuable guidance for other emerging economies seeking enhanced resource and environmental protection through the implementation of energy-saving and emission-reduction fiscal policy.

Magnetic anisotropy and planar topological Hall effect in SrMnxIr1-xO3films.

Strong Coulomb repulsion and spin-orbit coupling are known to give rise to exotic physical phenomena in transition metal oxides. Here, we report magnetic and transport characteristics of (001) oriented epitaxial SrMnxIr1-xO3thin films, having both 3dand 5delements on the perovskiteBsites. With the increase of Mn concentration, perpendicular magnetic anisotropy (PMA) decreases gradually in accompany with the magnetic easy axis tilting away from the out-of-plane [001] direction. X-ray absorption spectroscopy reveals that Mnegelectrons preferentially occupy thed3z2-r2orbital, which produces the observed PMA in the framework of spin-orbital coupling. A planar topological Hall effect appears in SrMnxIr1-xO3films withxabout 0.30 when the magnetic field is applied along the current, which is a result of the noncoplanar spin structure due to the competition among the PMA, the magnetic exchange interaction and the Zeeman energy. These results provide an example to show the subtle balance among complex competitions in materials with both strong correlation and spin-orbit coupling.

Characteristics of plant growth-promoting rhizobacteria SCPG-7 and its effect on the growth of Capsicum annuum L.

The strain SCPG-7 was isolated from saline soil in a cotton field. It is confirmed that the strain SCPG-7 is Pseudomonas sp. by means of the analysis of its phenotypic features and 16S rRNA sequence. SCPG-7 was capable of dissolving mineral tri-calcium phosphate (Ca3(PO4)2) and tri-magnesium phosphate (Mg3(PO4)2). In contrast, no showing iron phosphate (FePO4) or aluminum phosphate (AlPO4) solubilizing activities were detected by this experimental approach. The ratio of the dissolved P diameter to the colony diameter was 1.86. To study the phosphate dissolving mechanisms of the strain, we analyzed the changes of the pH value, the soluble phosphate content, the concentration of alkaline phosphatase, and the production of organic acid in the insoluble phosphate liquid medium. 2-keto-D-gluconicacid, α-ketoglutaric acid, succinic acid, etc. were characterized by LC-MS/MS in NBRIP medium. The concentration of 2-keto-D-gluconicacid increased to 88.6 mg/L after being cultured for 216 h. The strain decreased the pH value of the medium from 7.4 to 4.7 and the released soluble phosphate up to 516 mg/L, which proved the production of organic acids and alkaline phosphatase to be mechanism for solubilizing P. Under low phosphorus stress, Pseudomonas global regulatory protein PhoB regulates the transcription of the alkaline phosphatase gene. IAA and siderophore were secreted by SCPG-7. After treatment with SCPG-7, the individual plant height and dry weight of pepper increased by 23.3 and 31.2%, respectively, compared to the control group. The results show that the strain SCPG-7 has the potential to convert insoluble inorganic phosphorus to plant-available phosphorus. It can enhance soil phosphorus release through biological pathways, thereby increasing crop yield, and providing germplasm resources for the development of biological fertilizers.

Toward Multifunctional Electronics: Flexible NBT-Based Film with a Large Electrocaloric Effect and High Energy Storage Property.

Advances in smart and wearable devices are driving innovations in multifunctional flexible materials at a tremendous pace. Here, drawing support from the unique flexible fluorophlogopite mica platform, we present a promising all-inorganic bendable Mn-modified 0.65(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-0.35SrTiO3 (NBBST) film with dual use in electrocaloric (EC) refrigeration and energy storage via a cost-effective transfer-free process. An appreciable room-temperature EC effect with adiabatic temperature change of 12 K and isothermal entropy of 18 J K-1 kg-1 was realized in the NBBST film, which benefits from the large change in dipolar ordering near depolarization temperature. Also, the film exhibits a broad operating temperature span over 25 °C because of its relaxor feature. Most importantly, the film can maintain a high EC performance either under bending deformation at 5 mm radius or after undergoing 104 bending-unbending cycles. Meanwhile, the flexible NBBST film possesses good energy storage property with a recoverable energy density of 56 J cm-3 and an efficiency of 66%. This is the first example of a lead-free all-inorganic multifunctional film capacitor toward the flexible EC refrigeration and energy storage devices. This work shows bright prospects in the emerging flexible e-market.

Flexible, Temperature-Resistant, and Fatigue-Free Ferroelectric Memory Based on Bi(Fe0.93Mn0.05Ti0.02)O3 Thin Film.

A recent hot-spot topic for flexible and wearable devices involves high-performance nonvolatile ferroelectric memories operating under compressive or tensile mechanical deformations. This work presents the direct fabrication of a flexible (Mn,Ti)-codoped multiferroic BiFeO3 film capacitor with Pt bottom and Au top electrodes on mica substrate. The fabricated polycrystalline Bi(Fe0.93Mn0.05Ti0.02)O3 film on mica exhibits superior ferroelectric switching behavior with robust saturated polarization ( Ps ∼ 93 µC/cm2) and remanent polarization ( Pr ∼ 66 µC/cm2) and excellent frequency stability (1-50 kHz) and temperature resistance (25-200 °C), as well as reliable long-lifetime operation. More saliently, it can be safely bent to a small radius of curvature, as low as 2 mm, or go through repeated compressive/tensile mechanical flexing for 103 bending times at 4 mm radius without any obvious deterioration in polarization, retention time at 105 s, or fatigue resistance after 109 switching cycles. These findings demonstrate a novel route to designing flexible BiFeO3-based ferroelectric memories for information storage and data processing, with promising applications in next-generation smart electronics.

Electrochemical sensing platform based on the biomass-derived microporous carbons for simultaneous determination of ascorbic acid, dopamine, and uric acid.

A novel and highly selective electrochemical sensing platform (ZnCl2-CF/GCE) based on combination of kiwi skin and zinc chloride nanoparticles was developed for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The constructed electrode shows a high surface area and micro-mesoporous structure. And the electrochemical behaviors of the electrode were further explored by cyclic voltammetry (CV), impedance analysis (EIS), and differential pulse voltammetry (DPV). Under the optimal conditions, the ZnCl2-CF provides a high sensitivity and selective signaling in the co-existence system of AA, DA, and UA with linear response ranges of 0.05-200 µM, 2-2000 µM, and 1-2500 µM, respectively. The detection limits (S/N = 3) were calculated to be 0.02 µM, 0.16 µM, and 0.11 µM, respectively. In addition, the method has been successfully applied to determine AA, DA, and UA in real samples, which provides potential applications in further sensing study.

Degradation of pendimethalin by the yeast YC2 and determination of its two main metabolites.

In this study, we isolated a yeast strain, YC2, by enrichment culture from pendimethalin-contaminated soil. The analysis of its phenotypic features and 26S rRNA sequence confirmed that the strain YC2 is Clavispora lusitaniae. According to the kinetics of pendimethalin degradation, YC2 could degrade 74% of 200 mg L-1 pendimethalin in CMB liquid culture over 8 days. LC-MS/MS was used to identify the metabolites of pendimethalin after degradation. This study confirmed that its metabolites consist of 1,2-dimethyl-3,5-dinitro-4-N(buta-1,3-dien-2-yl)-dinitrobenzenamine-N-oxide and 1,2-dimethyl-3,5-dinitro-4-N(prop-1-en-2-yl)-dinitrobenzenamine-N-oxide, which were broken down by a series of enzymatic reactions to produce CO2 and H2O. Thus, the study herein sheds light on the role of yeast in the degradation of pendimethalin.

Effects of testosterone and flutamide on reproduction in Brachionus calyciflorus.

The effects of testosterone and flutamide on reproduction in Brachionus calyciflorus were studied. Asexual reproduction in B. calyciflorus was not affected by testosterone at different concentrations of flutamide. Flutamide in combination with 0, 25, 50, or 75 µg L-1 testosterone had a significant effect on mixis rate. The combination of 5 µg L-1 flutamide with 25 µg L-1 or 50 µg L-1 testosterone resulted in a mixis rate that was 2.2× lower than that with flutamide alone. Fertilization rate was significantly decreased by 7.5 µg L-1 flutamide in combination with 25, 50, or 75 µg L-1 testosterone. The number of resting eggs produced per mictic female was significantly lower at all concentrations of testosterone. A low concentration of flutamide in combination with testosterone resulted in antagonism, increasing the number of resting eggs produced. However, when testosterone was combined with a higher concentration of flutamide, resting egg production declined. Therefore, long-term exposure to either testosterone, flutamide, or a combination of these two compounds may significantly reduce resting egg production in rotifers. This implies that resting egg production is affected differently by hormone pathways.

Draft Genome Sequence of the Plant Growth-Promoting Bacterium Pseudomonas sp. SCPG-7, Isolated from Saline Soil.

Pseudomonas sp. SCPG-7 was isolated from saline soil. The strain can increase the germination rate of cotton seeds and promote the growth of cotton seedlings under salt stress conditions. The genome is 6,256,198 bp long, containing 5,672 predicted open reading frames.

Purification and characterization of a novel ubiquitin-like antitumour protein with hemagglutinating and deoxyribonuclease activities from the edible mushroom Ramaria botrytis.

A novel ubiquitin-like antitumour protein (RBUP) was isolated from fruiting bodies of the edible mushroom Ramaria botrytis. The protein was isolated with a purification protocol involving ion exchange chromatography on DEAE-Sepharose fast flow and gel filtration on Sephadex G-75. SDS-PAGE, Native-PAGE and ultracentrifugation analysis disclosed that RBUP was a monomeric protein with a molecular weight of 18.5 kDa. ESI-MS/MS demonstrated that it shared 69% amino acid sequence similarity with Coprinellus congregates ubiquitin (gi|136667). The protein exhibiting strong anticancer activity towards A549 cells. Analysis by employing AO/EB staining and Annexin V-FITC/PI detection indicated that the cytotoxic effect of RBUP was mediated through induction of apoptosis. Furthermore, RBUP displayed hemagglutinating and deoxyribonuclease activities. A temperature of 40 °C and pH of 7.0 were required for optimal DNase activity. Therefore, it was estimated that RBUP exerted its antitumour effect by inducing apoptosis, and its hemagglutinating and DNase activities were also thought to participate in this effect. These results demonstrated that RBUP was a multifunctional protein with potential medicinal applications.

A novel polysaccharide with antioxidant, HIV protease inhibiting and HIV integrase inhibiting activities from Fomitiporia punctata (P. karst.) murrill (Basidiomycota, hymenochaetales).

A novel polysaccharide fraction (G1) was obtained from the fungus Fomitiporia punctata (P. Karst.) Murrill. G1 exhibited a molecular weight of approximately 151kDa. The FT-IR results suggested that the monosaccharide components of G1 possessed furanoid rings and there were ß-glycosidic bonds between the sugar units. The1H NMR results showed that G1 was composed of arabinose, fructose, galactose and glucose in the molar ratio of 1.6:3.8:19.7:19.7, as determined by gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). G1 produced significant antioxidant effects as evidenced by its potency in inhibiting erythrocyte hemolysis, and in scavenging hydroxyl radicals and superoxide radicals. The highest rates of inhibition achieved were 73.58%, 36.55% and 50.98% respectively. In addition, G1 brought about 19.6% inhibition of HIV-1 protease activity at the concentration of 50µg/mL. G1 displayed inhibitory activity toward HIV-1 integrase in the concentration range of 100-1000µg/mL. The present study indicates that G1 from Fomitiporia punctate (P. Karst.) Murrill is a novel natural antioxidant.

Characterization of Raoultella planticola Rs-2 microcapsule prepared with a blend of alginate and starch and its release behavior.

To judiciously use Raoultella planticola Rs-2 and develop its biodegradable and controlled-release formulations, Rs-2 was encapsulated with various combinations of sodium alginate (NaAlg) and starch. Sodium alginate, soluble starch, and CaCl2 showed good biocompatibility with Rs-2 for preparing microcapsules. These microcapsules were spherical in shape and their particle size, embedding rate, swelling ratio of Rs-2 microcapsules and release numbers of viable Rs-2 cells increased with the increasing of starch and NaAlg concentrations. Meanwhile, the biodegradability of the microcapsules constantly increases when the wt% of starch increased, but decreased when the amount of NaAlg increased. In addition, the release mechanism of microcapsules was consistent with that of the Ritger-Peppas model, which involves the Case II diffusion mechanism. In summary, the desired properties of the microcapsules can be modulated by varying the starch and alginate amounts of capsule materials. This process has broad application prospects to meet the needs of agricultural production.