Carbon metabolism of a novel isolate from Lacticaseibacillus rhamnosus Probio-M9 derived through space mutant.

AIMS: Carbon source is a necessary nutrient for bacterial strain growth. In industrial production, the cost of using different carbon sources varies greatly. Moreover, the complex environment in space may cause metabolic a series of changes in the strain, and this method has been successfully applied in some basic research. To date, space mutagenesis is still limited number of studies, particularly in carbon metabolism of probiotics. METHODS AND RESULTS: HG-R7970-41 was isolated from bacterium suspension (Probio-M9) after space flight, which can produce capsular polysaccharide after space mutagenesis. Phenotype Microarray (PM) was used to evaluated the metabolism of HG-R7970-41 in 190 single carbon sources. RNA sequencing and total protein identification of two strains revealed their different carbon metabolism mechanisms. PM results demonstrated the metabolism of 10 carbon sources were different between Probio-M9 and HG-R7970-41. Transcriptomic and proteomic analyses revealed that this change in carbon metabolism of HG-R7970-41 mainly related to changes in phosphorylation and the glycolysis pathway. Based on the metabolic mechanism of different carbon sources and related gene cluster analysis, we found that the final metabolic activities of HG-R7970-41 and Probio-M9 were mainly regulated by PTS-specific membrane embedded permease (EII), carbohydrate kinase and two rate-limiting enzymes (phosphofructokinase (PFK) and pyruvate kinase (PYK)) in the glycolysis pathway. The expanded culture test also confirmed that HG-R7970-41 had different metabolic characteristics from original strain. CONCLUSIONS: These results suggested that space environment could change carbon metabolism of Probio-M9. The new isolate (HG-R7970-41) showed a different carbon metabolism pattern from the original strain mainly by the regulation of two rate-limiting enzymes.

Overlooked interconversion between tetracyclines and their 4-epimers in soil and effects on soil resistome and bacterial community.

With the widespread use of tetracycline antibiotics (TCs) and the application of manure fertilizer in farmland, TCs and their metabolites especially 4-epimers have been heavily detected in agricultural soil. However, existing studies have focused on the residual and environmental behavior of maternal TCs, and few studies have looked at the ecotoxicity of their 4-epimers in soil. In this study, the degradation and interconversion of tetracycline (TC), oxytetracycline (OTC) and their 4-epimers (4-epitetracycline, ETC; 4-epioxytetracycline, OTC) were revealed. Their effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial community in soil were also investigated in comparison. The results showed that the 4-epimers could be substantially transformed to their parents and degraded as a whole. The degradation rates of four selected pollutants are followed: TC > OTC > ETC > EOTC. This indicated that when TCs entered the soil, part of TCs transformed into slower-degraded 4-epimers, and these 4-epimers could also be converted back to their antibiotic parents, causing the long-term residue of TCs in soil. When added to the soil alone, TC and OTC significantly promoted the proliferation of most ARGs and MGEs, among them, trb-C, IS1247 and IS1111 were the top three genes in abundance. ETC and EOTC had little effect at the beginning. However, as the 4-epimers continuously converted into their parents after one month of cultivation, ETC and EOTC treatments showed similar promoting effect on ARGs and MGEs, indicating that the effect of ETC and EOTC on soil resistome was lagged and mainly caused by their transformed parents. Nocardioides, unclassified_Rhizobiaceae, norank_Sericytochromatia, Microlunatus, Solirubrobacter and norank_67-14 were the most frequent hosts of ARGs, Most of which belong to the phylum Actinobacteria. Due to their large transformation to TCs, slow degradation rate and potential effects on soil microbes and ARGs, the harm of TCs' 4-epimers on soil ecosystem cannot be ignored.

Identification of novel dual-target 4-hydroxyphenylpyruvate dioxygenase & phytoene dehydrogenase inhibitors via multiple virtual screening.

Two important plant enzymes are 4-hydroxyphenylpyruvate dioxygenase (HPPD; EC 1.13.11.27), which is necessary for biosynthesis of plastoquinone and tocopherols, and phytoene dehydrogenase (PDS; EC 1.3.99.26), which plays an important role in colour rendering. Dual-target proteins that inhibit pigment synthesis will prevent resistant weeds and improve the spectral characteristics of herbicides. This study introduces virtual screening of pharmacophores based on the complex structure of the two targets. A three-dimensional database was established by screening 1,492,858 compounds based on the Lipinski principle. HPPD&PDS dual-target receptor-ligand pharmacophore models were then constructed, and nine potential dual-target inhibitors were obtained through pharmacophore modeling, molecular docking, and molecular dynamics simulations. Ultimately, ADMET prediction software yielded three compounds with high potential as dual-target herbicides. The obtained nine inhibitors were stable when combined with both HPPD and PDS proteins. This study offers guidance for the development of HPPD&PDS dual-target inhibitors with novel skeletons.

4-Hydroxyphenylpyruvate Dioxygenase Inhibitors: From Molecular Design to Synthesis.

Weed resistance is a critical issue in crop production. Among the known herbicides, 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors are crucial for addressing weed resistance. HPPD inhibitors constitute a pivotal aspect of contemporary crop protection strategies. The advantages of these herbicides are their broad weed spectrum, flexible application, and excellent compatibility with other herbicides. They also exhibit satisfactory crop selectivity and low toxicity and are environmentally friendly. An increasing number of new HPPD inhibitors have been designed by combining computer-aided drug design with conventional design approaches. Herein, the molecular design and structural features of innovative HPPD inhibitors are reviewed to guide the development of new HPPD inhibitors possessing an enhanced biological efficacy.

Dual-recognition "turn-off-on" fluorescent Biosensor triphenylamine-based continuous detection of copper ion and glyphosate applicated in environment and living system.

Heavy metal Cu2+ emitted in industry and residues of glyphosate pesticides are pervasive in ecosystems, accumulated in water bodies and organisms' overtime, constituting hazard to human and ecological balance. The development of rapid, highly selective, reversibility and sensitive biosensor in vivo detection for Cu2+ and glyphosate was imminent. A novel dual-recognition fluorescence biosensor MPH was successfully synthesized based on triphenylamine, which demonstrated remarkable ratiometric fluorescence quenching toward Cu2+, while MPH-Cu2+ (1:1) ensemble exhibited ratiometric fluorescence restoration for glyphosate, both with observable color changes in daylight and UV lamp. The biosensor exhibited rapid, outstanding selectivity, anti-interference, and multiple cycles reversibility through "turn-off-on" fluorescence towards Cu2+ and glyphosate, respectively. Surprisingly, the clearly binding mechanisms of MPH to Cu2+ and MPH-Cu2+ ensemble to glyphosate were determined, respectively, based on the Job's plot, FT-IR, ESI-HRMS, 1H NMR titration and theoretical calculations of dynamics and thermodynamics. In addition, biosensor MPH demonstrated successful detection of Cu2+ and glyphosate across diverse environmental samples including tap water, extraction solutions of traditional Chinese medicine honeysuckle and soil samples. In the meantime, fluorescence imaging of Cu2+ and glyphosate at both micro and macro scales in various living organisms, such as rice roots, MCF-7 cells, zebrafish, and mice, were successfully achieved. Overall, this work was expected to become a promising and versatile fluorescence biosensor for rapid and reversible detection of Cu2+ and glyphosate both in vitro and vivo.

Transparent Superhydrophobic and Self-Cleaning Coating.

Surface roughness and low surface energy are key elements for the artificial preparation of biomimetic superhydrophobic materials. However, the presence of micro-/nanostructures and the corresponding increase in roughness can increase light scattering, thereby reducing the surface transparency. Therefore, designing and constructing superhydrophobic surfaces that combine superhydrophobicity with high transparency has been a continuous research focus for researchers and engineers. In this study, a transparent superhydrophobic coating was constructed on glass substrates using hydrophobic fumed silica (HF-SiO2) and waterborne polyurethane (WPU) as raw materials, combined with a simple spray-coating technique, resulting in a water contact angle (WCA) of 158.7 ± 1.5° and a sliding angle (SA) of 6.2 ± 1.8°. Characterization tests including SEM, EDS, LSCM, FTIR, and XPS revealed the presence of micron-scale protrusions and a nano-scale porous network composite structure on the surface. The presence of HF-SiO2 not only provided a certain roughness but also effectively reduced surface energy. More importantly, the coating exhibited excellent water-repellent properties, extremely low interfacial adhesion, self-cleaning ability, and high transparency, with the light transmittance of the coated glass substrate reaching 96.1% of that of the bare glass substrate. The series of functional characteristics demonstrated by the transparent superhydrophobic HF-SiO2@WPU coating designed and constructed in this study will play an important role in various applications such as underwater observation windows, building glass facades, automotive glass, and goggles.

In vitro generation of trophoblast like stem cells from goat pluripotent stem cells.

Since the first mouse induced pluripotent stem cells (iPSCs) was derived, the in vitro culture of domestic iPSCs functionally and molecularly comparable with mouse iPSCs has been a challenge. Here, we established dairy goat iPSCs (giPSCs) from goat ear fibroblast cells with mouse iPSCs morphology, the expression of pluripotent markers and differentiation ability in vitro delivered by piggyBac transposon with nine Dox-inducible exogenous reprogramming factors. These reprogramming factors were bOMSK (bovine OCT4, CMYC, SOX2, and KLF4), pNhL (porcine NANOG and human LIN28), hRL (human RARG and LRH1), and SV40 Large T. Notably, AF-giPSCs (induced in activin A and bFGF condition) were capable of differentiation in embryoid bodies in vitro and could contribute to interspecies chimerism in mouse E6.5 embryos in vitro, demonstrating that AF-giPSCs have the developmental capability to generate some embryonic cell lineages. Moreover, Wnt/ß-catenin signaling has an important role in driving goat induced trophoblast-like stem cells (giTLSCs) from Dox-independent giPSCs. This study will support further establishment of the stable giPSC lines without any integration of exogenous genes.

Biotemplated Fe/La-co-doped TiO2 for photocatalytic depth treatment of compressed leachate from refuse transfer station.

Compressed leachate is a contaminated liquid containing various organic and inorganic pollutants produced in municipal refuse transfer stations, which pollute soil and groundwater, posing serious risks to the environment and human health. The Environmental Technology Co., Ltd. (Shenzhen, Guangdong Province, South China) treated compressed leachate obtained from a refuse transfer station. The chemical oxygen demand (COD) (641.2 mg/L) of treated compressed leachate did not meet the wastewater quality standards in China for discharge into municipal sewers (COD ≤ 500 mg/L) and the company's design discharge requirements (COD ≤ 400 mg/L). Therefore, their further in-depth treatment is necessary. To this end, waste tobacco leaves were used as the biotemplate herein, and Fe/La-co-doped TiO2 (xFe,yLa)-TTiO2(g) was synthesized using a solvothermal-assisted biotemplating method. The photocatalytic depth treatment of compressed leachate was performed under simulated solar light using the prepared catalysts. After (3Fe,3La)-TTiO2(g) treatment, the COD of the leachate decreased from 641.2 to 280.1 mg/L, and the COD removal rate was 1.2, 1.1, and 1.6 times higher than that of pure Fe-doped, La-doped and non-biological template TiO2, respectively. Characterization confirmed that the biological template endowed the catalyst with a unique morphology and high specific surface area. Its rich activity sites are conducive to enhancing the adsorption capacity of pollutants and providing an ideal place for photocatalytic reactions. Co-doping with iron and lanthanum ions altered the band structure of TiO2 and promoted the interconversion of Fe3+/Fe2+ and La3+/La2+ during photocatalysis. First-principles density functional theory simulations demonstrated that co-doping Fe and La in TiO2 created impurity levels that facilitated the transfer of photogenerated electrons. This study provides a new purification pathway for the depth treatment of compressed leachate.

Obesity induced caveolin-1 impairs osteogenesis via activating mitophagy and inhibiting Sirt1 signaling.

Obesity has become a major global health problem and the effect on bone formation has received increasing attention. However, the interaction between obesity and bone metabolism is complex and still not fully understood. Here, we show that caveolin-1 (Cav1), a membrane scaffold protein involved in regulating a variety of cellular processes, plays a key regulatory role as a bridge connecting obesity and bone metabolism. High-fat diet (HFD)-induced obese C57BL/6J mouse displayed a significant increase in Cav1 expression and lower osteogenic activity; In vitro treatment of osteoblastic MC3T3-E1 cells with 1 mM free fatty acids (FFA) significantly promoted Cav1 expression and PINK1/Parkin regulated mitophagy, but inhibited the expression of osteogenic marker genes. Conversely, reduced expression of the Cav1 gene prevented these effects. Both endogenous oxidative stress and Sirt1 pathway were also significantly reduced after Cav1 knockdown in FFA-treated cells. Finally, Cav1-Sirt1 docking and co-immunoprecipitation results showed that Cav1 interacted with Sirt1 and FFA enhanced the interaction. Taken together, these results suggest that obesity impairs bone development and formation through up-regulation of the Cav1 gene, which lead to inhibition of Sirt1/FOXO1 and Sirt1/PGC-1α signaling pathways through interacting with Sirt1 molecule, and an increase of mitophagy level.

High throughput identification of carbonyl compounds in natural organic matter by directional derivatization combined with ultra-high resolution mass spectrometry.

Carbonyl compounds are important components of natural organic matter (NOM) with high reactivity, so that play a pivotal role in the dynamic transformation of NOM. However, due to the lack of effective analytical methods, our understanding on the molecular composition of these carbonyl compounds is still limited. Here, we developed a high-throughput screening method to detect carbonyl molecules in complex NOM samples by combining chemical derivatization with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). In six different types of dissolved organic matter (DOM) samples tested in this study, 20-30 % of detected molecules contained at least one carbonyl group, with relative abundance accounted for 45-70 %. These carbonyl molecules displayed lower unsaturation level, lower molecular weight, and higher oxidation degree compared to non-carbonyl molecules. More importantly, the measured abundances of carbonyl molecules were consistent with the results of 13C nuclear magnetic resonance (NMR) analysis. Based on this method, we found that carbonyl molecules can be produced at DOM-ferrihydrite interface, thus playing a role in shaping the molecular diversity of DOM. This method has broad application prospects in screening carbonyl compounds from complex mixtures, and the same strategy can be used to directional identification of molecules with other functional groups as well.

Probiotic-derived amphiphilic exopolysaccharide self-assembling adjuvant delivery platform for enhancing immune responses.

Enhancing immune response activation through the synergy of effective antigen delivery and immune enhancement using natural, biodegradable materials with immune-adjuvant capabilities is challenging. Here, we present NAPSL.p that can activate the Toll-like receptor 4 (TLR4) pathway, an amphiphilic exopolysaccharide, as a potential self-assembly adjuvant delivery platform. Its molecular structure and unique properties exhibited remarkable self-assembly, forming a homogeneous nanovaccine with ovalbumin (OVA) as the model antigen. When used as an adjuvant, NAPSL.p significantly increased OVA uptake by dendritic cells. In vivo imaging revealed prolonged pharmacokinetics of NAPSL. p-delivered OVA compared to OVA alone. Notably, NAPSL.p induced elevated levels of specific serum IgG and isotype titers, enhancing rejection of B16-OVA melanoma xenografts in vaccinated mice. Additionally, NAPSL.p formulation improved therapeutic effects, inhibiting tumor growth, and increasing animal survival rates. The nanovaccine elicited CD4+ and CD8+ T cell-based immune responses, demonstrating the potential for melanoma prevention. Furthermore, NAPSL.p-based vaccination showed stronger protective effects against influenza compared to Al (OH)3 adjuvant. Our findings suggest NAPSL.p as a promising, natural self-adjuvanting delivery platform to enhance vaccine design across applications.

Facile synthesis of Bi3O(OH)(AsO4)2 and simultaneous photocatalytic oxidation and adsorption of Sb(III) from wastewater.

Antimony (Sb) decontamination in water is necessary owing to the worsening pollution which seriously threatens human life safety. Designing bismuth-based photocatalysts with hydroxyls have attracted growing interest because of the broad bandgap and enhanced separation efficiency of photogenerated electron/hole pairs. Until now, the available photocatalysis information regarding bismuth-based photocatalysts with hydroxyls has remained scarce and the contemporary report has been largely limited to Bi3O(OH)(PO4)2 (BOHP). Herein, Bi3O(OH)(AsO4)2 (BOHAs), a novel ultraviolet photocatalyst, was fabricated via the co-precipitation method for the first time, and developed to simultaneous photocatalytic oxidation and adsorption of Sb(III). The rate constant of Sb(III) removal by the BOHAs was 32.4, 3.0, and 4.3 times higher than those of BiAsO4, BOHP, and TiO2, respectively, indicating that the introduction of hydroxyls could increase the removal of Sb(III). Additionally, the crucial operational parameters affecting the adsorption performance (catalyst dosage, concentration, pH, and common anions) were investigated. The BOHAs maintained 85% antimony decontamination of the initial yield after five successive cycles of photocatalysis. The Sb(III) removal involved photocatalytic oxidation of adsorbed Sb(III) and subsequent adsorption of the yielded Sb(V). With the acquired knowledge, we successfully applied the photocatalyst for antimony removal from industrial wastewater. In addition, BOHAs could also be powerful photocatalysts in the photodegradation of organic pollutants studies of which are ongoing. It reveals an effective strategy for synthesizing bismuth-based photocatalysts with hydroxyls and enhancing pollutants' decontamination.

Direct electrospinning for producing multiple activity nanofibers consisting of aggregated luteolin/hydroxypropyl-gamma-cyclodextrin inclusion complex.

Hydroxypropyl-gamma-cyclodextrin (HPγCD) inclusion complex nanofibers (Lut/HPγCD-IC-NF) containing Luteolin (Lut) were prepared by electrospinning technology. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectra confirmed the formation of Lut/HPγCD-IC-NF. Scanning electron microscopy (SEM) images showed that the morphology of Lut/HPγCD-IC-NF was uniform and bead-free, suggesting that self-assembled aggregates, macromolecules with higher molecular weights, were formed by strong hydrogen bonding interactions between the cyclodextrin inclusion complexes. Confocal laser scanning microscopy (CLSM) images showed that Lut was distributed in Lut/HPγCD-IC-NF. Proton nuclear magnetic resonance (1H NMR) spectroscopy revealed the change in chemical shift of the proton peak between Lut and HPγCD, confirming the formation of inclusion complex. Thermogravimetric analysis (TGA) proved that Lut/HPγCD-IC-NF had good thermal stability. The phase solubility test confirmed that HPγCD had a solubilizing effect on Lut. When the solubility of HPγCD reached 10 mM, the solubility of Lut increased by 15-fold. The drug loading test showed that the content of Lut in fibers reached 8.57 ± 0.02 %. The rapid dissolution experiment showed that Lut/HPγCD-IC-NF dissolved within 3 s. The molecular simulation provides three-dimensional evidence for the formation of inclusion complexes between Lut and HPγCD. Antibacterial experiments showed that Lut/HPγCD-IC-NF had enhanced antibacterial activity against S. aureus. Lut/HPγCD-IC-NF exhibited excellent antioxidant properties with a free radical scavenging ability of 89.5 ± 1.1 %. In vitro release experiments showed Lut/HPγCD-IC-NF had a higher release amount of Lut. In conclusion, Lut/HPγCD-IC-NF improved the physicochemical properties and bioavailability of Lut, providing potential applications of Lut in the pharmaceutical field.

An Ultra-broadband Metallic Plasmonic Antenna for Ultrasensitive Molecular Fingerprint Identification.

Near-field enhanced mid-infrared light-matter interactions via metallic plasmonic antennae (PA) have attracted much attention but are inevitably limited by the detuning between their narrow band and the broad applied spectral range. Here, we develop a new low-temperature incubation synthetic method to acquire uniform Ag microparticles (MPs) with numerous hotspots. Their plasmonic band is remarkably extended by the plasmonic coupling of numerous hotspots and covers the entire mid-infrared range (400-4000 cm-1). Hence, the almost complete molecular fingerprint of 4-mercaptobenzonitrile was successfully probed for the first time via resonant surface-enhanced infrared absorption (rSEIRA), and the rSEIRA spectra of different essential amino acids were further detected and exhibit a high spectral identification degree assisted by machine learning. This work changes the inertia perception of "narrow band and large size but small hotspot area" of mid-infrared metallic PA and paves the way for the ultrasensitive mid-infrared optical sensing.

Streptococcus hohhotensis sp. nov., isolated from the breast milk of a healthy woman.

Human breast milk contains lactic acid bacteria (LAB), which have an important influence on the composition of the intestinal microbia of infants. In this study, one strain of an α-hemolytic species of the genus Streptococcus, IMAU99199T, isolated from the breast milk of a healthy nursing mother in Hohhot city PR China, was studied to characterise its taxonomic status using phenotypic and molecular taxonomic methods. The results indicated that it represented a member of the mitis-suis clade, pneumoniae subclade of the genus Streptococcus. It is a Gram-stain-positive, catalase-negative and oxidase-negative bacterium, and the cells are globular, paired or arranged in short chains. The results of a phylogenetic analysis of its 16S rRNA gene and two housekeeping genes (gyrB and rpoB) placed it in the genus Streptococcus. A phylogenetic tree based on 135 single-copy genes sequences indicated that IMAU99199T formed a closely related branch well separated from 'Streptococcus humanilactis' IMAU99125, 'Streptococcus bouchesdurhonensis' Marseille Q6994, Streptococcus mitis NCTC 12261T, 'Streptococcus vulneris' DM3B3, Streptococcus toyakuensis TP1632T, Streptococcus pseudopneumoniae ATCC BAA-960T and Streptococcus pneumoniae NCTC 7465T. IMAU99199T and 'S. humanilactis' IMAU99125 had the highest average nucleotide identity (93.7 %) and digital DNA-DNA hybridisation (55.3 %) values, which were below the accepted thresholds for novel species. The DNA G+C content of the draft genome of IMAU99199T was 39.8 %. The main cellular fatty acids components of IMAU99199T were C16 : 0 and C16 : 1ω7. It grew at a temperature range of 25-45 °C (the optimum growth temperature was 37 °C) and a pH range of 5.0-8.0 (the optimum growth pH was 7.0). These data indicate that strain IMAU99199T represents a novel species in the genus Streptococcus, for which the name Streptococcus hohhotensis sp. nov. is proposed. The type strain is IMAU99199T (=GDMCC 1.1874T=KCTC 21155T).

Plasticity of Adipose Tissues: Interconversion among White, Brown, and Beige Fat and Its Role in Energy Homeostasis.

Obesity, characterized by the excessive accumulation of adipose tissue, has emerged as a major public health concern worldwide. To develop effective strategies for treating obesity, it is essential to comprehend the biological properties of different adipose tissue types and their respective roles in maintaining energy balance. Adipose tissue serves as a crucial organ for energy storage and metabolism in the human body, with functions extending beyond simple fat storage to encompass the regulation of energy homeostasis and the secretion of endocrine factors. This review provides an overview of the key characteristics, functional differences, and interconversion processes among white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue. Moreover, it delves into the molecular mechanisms and recent research advancements concerning the browning of WAT, activation of BAT, and whitening of BAT. Although targeting adipose tissue metabolism holds promise as a potential approach for obesity treatment, further investigations are necessary to unravel the intricate biological features of various adipose tissue types and elucidate the molecular pathways governing their interconversion. Such research endeavors will pave the way for the development of more efficient and targeted therapeutic interventions in the fight against obesity.

Design, Synthesis, and Biological Activity of Novel Phenyltriazolinone PPO Inhibitors Containing Five-Membered Heterocycles.

Protoporphyrinogen oxidase (PPO, EC 1.3.3.4) catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX, which is a key step in the synthesis of porphyrins in vivo. PPO inhibitors use protoporphyrinogen oxidase as the target and block the biosynthesis process of porphyrin by inhibiting the activity of the enzyme, eventually leading to plant death. In this paper, phenyl triazolinone was used as the parent structure, and the five-membered heterocycle with good herbicidal activity was introduced by using the principle of substructure splicing. According to the principle of bioisosterism, the sulfur atoms on the thiophene ring were replaced with oxygen atoms. Finally, 33 phenyl triazolinones and their derivatives were designed and synthesized, and their characterizations and biological activities were investigated. The in vitro PPO inhibitory activity and greenhouse herbicidal activity of 33 target compounds were determined, and compound D4 with better activity was screened out. The crop safety determination, field weeding effect determination, weeding spectrum determination, and crop metabolism study were carried out. The results showed that compound D4 showed good safety to corn, soybean, wheat, and peanut but poor selectivity to cotton. The field weeding effect of this compound is comparable to that of the commercial herbicide sulfentrazone. The herbicidal spectrum experiment showed that compound D4 had a wide herbicidal spectrum and a good growth inhibition effect on dicotyledonous weeds. Molecular docking results showed that compound D4 forms a hydrogen bond with amino acid residue Arg-98 in the tobacco mitochondria (mtPPO)-active pocket and forms two π-π stacking interactions with Phe-392. This indicates that compound D4 has stronger PPO inhibitory activity. This indicates that compound D4 has wide prospects for development.

Fulvic acid more facilitated the soil electron transfer than humic acid.

Humus substances (HSs) participate in extracellular electron transfer (EET), which is unclear in heterogeneous soil. Here, a microbial electrochemical system (MES) was constructed to determine the effect of HSs, including humic acid, humin and fulvic acid, on soil electron transfer. The results showed that fulvic acid led to the optimal electron transfer efficiency in soil, as evidenced by the highest accumulated charges and removal of total petroleum hydrocarbons after 140 days, with increases of 161% and 30%, respectively, compared with those of the control. However, the performance of MES with the addition of humic acid and humin was comparable to that of the control. Fulvic acid amendment enhanced the carboxyl content and oxidative state of dissolved organic matter, endowing a better electron transfer capacity. Additionally, the presence of fulvic acid induced an increase in the abundance of electroactive bacteria and organic degraders, extracellular polymeric substances and functional enzymes such as cytochrome c and NADH synthesis, and the expression of m tr C gene, which is responsible for EET enhancement in soil. Overall, this study reveals the mechanism by which HSs stimulate soil electron transfer at the physicochemical and biological levels and provides basic support for the application of bioelectrochemical technology in soil.