Disentangling microbial coupled fillers mechanisms for the permeable layer optimization process in multi-soil-layering systems.

The multi-soil-layering (MSL) systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater. However, the role of the seemingly simple permeable layer has been overlooked, potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems. In this paper, the mechanism among diverse substrates (zeolite, green zeolite and biological ceramsite) coupled microorganisms in different systems (activated bacterial powder and activated sludge) for rural domestic wastewater purification was investigated. The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8% for COD, 97.1% for TP, and 98.8% for NH4+-N. Notably, activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder. Zeolite attained an impressive 89.4% NH4+-N desorption efficiency, with a substantive fraction of NH4+-N manifesting as exchanged ammonium. High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor, with anaerobic bacteria conspicuously absent. And the heterotrophic nitrification-aerobic denitrification (HN-AD) process was significant, with the presence of denitrifying phosphorus-accumulating organisms (DPAOs) for simultaneous nitrogen and phosphorus removal. This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems, but also provides valuable insights for optimizing MSL system construction, operation, and rural domestic wastewater treatment.

Comparative genomics of the carmine cochineal symbiont Candidatus Dactylopiibacterium carminicum reveals possible protection to the host against viruses via CRISPR/Cas.

We present new genomes from the bacterial symbiont Candidatus Dactylopiibacterium carminicum obtained from non-domesticated carmine cochineals belonging to the scale insect Dactylopius (Hemiptera: Coccoidea: Dactylopiidae). As Dactylopiibacterium has not yet been cultured in the laboratory, metagenomes and metatranscriptomics have been key in revealing putative symbiont functions. Dactylopiibacterium is a nitrogen-fixing beta-proteobacterium that may be vertically transmitted and shows differential gene expression inside the cochineal depending on the tissue colonized. Here we found that all cochineal species tested had Dactylopiibacterium carminicum which has a highly conserved genome. All Dactylopiibacterium genomes analyzed had genes involved in nitrogen fixation and plant polymer degradation. Dactylopiibacterium genomes resemble those from free-living plant bacteria, some found as endophytes. Notably, we found here a new putative novel function where the bacteria may protect the insect from viruses, since all Dactylopiibacterium genomes contain CRISPRs with a spacer matching nucleopolyhedrovirus that affects insects.

Metagenomic unveils the promotion of mainstream PD-anammox process at lower nZVI concentration and inhibition at higher dosage.

The partial-denitrification-anammox (PdNA) process exhibits great potential in enabling the simultaneous removal of NO3--N and NH4+-N. This study delved into the impact of exogenous nano zero-valent iron (nZVI) on the PdNA process. Adding 10 mg L-1 of nZVI increased nitrogen removal efficiency up to 83.12 % and maintained higher relative abundances of certain beneficial bacteria. The maximum relative abundance of Candidatus Brocadia (1.6 %), Candidatus Kuenenia (1.5 %), Ignavibacterium (1.3 %), and Azospira (1.2 %) was observed at 10 mg L-1 of nZVI. However, the greatest relative abundance of Thauera (1.3 %) was recorded under 50 mg L-1. Moreover, applying nZVI selectively enhanced the abundance of NO3--N reductase genes. So, keeping the nZVI concentration at 10 mg L-1 or below is advisable to ensure a stable PdNA process in mainstream conditions. Considering nitrogen removal efficiency, using nZVI in the PD-anammox process could be more cost-effective in enhancing its adoption in industrial and mainstream settings.

Feasibility of simultaneous optimization of Anammox start-up and nitrogen removal performance by intermittent dosing of nanoscale zero-valent iron.

The long acclimation period and sensitivity to environmental conditions of Anammox are the bottlenecks for its promotion and application. An innovative strategy was adopted to accelerate functional microbial enhancement and improve nitrogen removal performance by inoculating cryopreserved Anammox sludge and activated sludge with intermittent dosing of nanoscale zero-valent iron (nZVI). The acclimation time was shortened by 76 days with nitrogen removal efficiency (NRE) reaching up to 91.07 %. Anammox, NDFO (nitrate/nitrite-dependent Fe(II) oxidation), Feammox (Fe(III) reduction coupled with anaerobic ammonium oxidation) and abiotic reactions were coupled in the system with nZVI, contributing to 69.79 %, 15.14 %, 9.84 % and 0.25 % of nitrogen removal, respectively. Further microbial analysis demonstrated significant enrichment of functional microorganisms such as Candidatus Jettenia, Acidovorax and Comamonas. High-efficient nitrogen removal was attribute to the increase of functional genes involved in Anammox, electronic transfer, heme C synthesis and iron metabolism. This work provides an inspiring idea for the mainstream Anammox application.

Energy recovery from syngas and pyrolysis wastewaters with anaerobic mixed cultures.

The anaerobic digestion of aqueous condensate from fast pyrolysis is a promising technology for enhancing carbon and energy recovery from waste. Syngas, another pyrolysis product, could be integrated as a co-substrate to improve process efficiency. However, limited knowledge exists on the co-fermentation of pyrolysis syngas and aqueous condensate by anaerobic cultures and the effects of substrate toxicity. This work investigates the ability of mesophilic and thermophilic anaerobic mixed cultures to co-ferment syngas and the aqueous condensate from either sewage sludge or polyethylene plastics pyrolysis in semi-batch bottle fermentations. It identifies inhibitory concentrations for carboxydotrophic and methanogenic reactions, examines specific component removal and assesses energy recovery potential. The results show successful co-fermentation of syngas and aqueous condensate components like phenols and N-heterocycles. However, the characteristics and load of the aqueous condensates affected process performance and product formation. The toxicity, likely resulting from the synergistic effect of multiple toxicants, depended on the PACs' composition. At 37 °C, concentrations of 15.6 gCOD/gVSS and 7.8 gCOD/gVSS of sewage sludge-derived aqueous condensate inhibited by 50% carboxydotrophic and methanogenic activity, respectively. At 55 °C, loads between 3.9 and 6.8 gCOD/gVSS inhibited by 50% both reactions. Polyethylene plastics condensate showed higher toxicity, with 2.8 gCOD/gVSS and 0.3 gCOD/gVSS at 37 °C decreasing carboxydotrophic and methanogenic rates by 50%. At 55 °C, 0.3 gCOD/gVSS inhibited by 50% CO uptake rates and methanogenesis. Increasing PAC loads reduced methane production and promoted short-chain carboxylates formation. The recalcitrant components in sewage sludge condensate hindered e-mol recovery, while plastics condensate showed high e-mol recoveries despite the stronger toxicity. Even with challenges posed by substrate toxicity and composition variations, the successful conversion of syngas and aqueous condensates highlights the potential of this technology in advancing carbon and energy recovery from anthropogenic waste streams.

Strengthening nitrogen removal of rural wastewater treatment in humus biochemical system under low dissolved oxygen conditions: Sludge and microbial characteristics.

To achieve efficient and cost-effective treatment for the rural wastewater, a novel humus biochemical system (HBS) process derived from humus bio-functional material was proposed to treat rural wastewater under low dissolved oxygen (DO) conditions, and the operational performance, sludge characteristics, and microbial community in HBS were systematically investigated in this study. The results indicated that the HBS reactor could be operated stably under low DO levels of 0.2-0.8 mg/L, and maintained high removal efficiencies of 96.4%, 96.0%, and 88.2% for chemical oxygen demand, ammonia nitrogen, and total nitrogen, with corresponding effluent concentrations of 11.0, 1.7, and 5.1 mg/L, respectively. The sludge produced from HBS was characterized by relatively large particle size, complex structural morphology, and abundant humic substances, which favorably improved the system stability. Illumina sequencing demonstrated that HBS reactor possessed high microbial abundance and diversity and was enriched with plenty of nitrifying and denitrifying bacteria, which synergistically intensified the whole biological nitrogen removal process in this system. The study presented the feasibility and adaptability of HBS for energy-efficient rural wastewater treatment.

Determination of ammonia nitrogen by surface-enhanced Raman spectroscopy and DFT studies.

Ammonia nitrogen is one of the most important indicators for evaluating the quality of water bodies. It is very difficult to determine ammonia nitrogen directly by Surface-enhanced Raman spectroscopy (SERS) in practice. In order to realize SERS determination of ammonia nitrogen, in this paper, SERS combined with density functional theory (DFT) was used to investigate why ammonia nitrogen needs to be derivatized to hexamethylenetetramine (HMTA) and why HMTA can be determined using SERS. The molecular electrostatic potential (MEP) results exhibit that there was no adsorption site on the surface of ammonia nitrogen, whereas its derivate HMTA had four available adsorption sites. This provides a basic guarantee for the SERS detection of HMTA. The molecular adsorption state of HMTA on the gold nanoparticles surface was concluded from the binding energies, the bond length, and the Raman activity spectra. Among them, the HMTA-Au4 complex has the lowest bond energy (-586.873 Kcal/mol) and the shortest bond length (2.161 Å), which is the most stable state and its Raman activity spectrum is the closest to the experimental data. Calculations results of frontier molecular orbital (FMO) demonstrate that the energy gap of HMTA and HMTA-Au4 complex are 0.30258 eV and 0.10947 eV, respectively, with a really obvious difference between them, which indicates that the HMAT-Au4 complex possessed higher chemical reactivity. In addition, charge transfer phenomenon on the MEP of HMTA-Au4 complex was deduced due to the change in the symmetry of its charge distribution, which can be explained the mechanism of chemical enhancement in the detection of HMTA by SERS. The selective enhancement at 1048 cm-1 peaks in theoretical spectrum and at 1044 peaks cm-1 in experimental spectrum provided theoretical and practical basis for indirect determination of ammonia nitrogen by SERS. The obtained results will help to better understand the reasons why some components are difficult to be directly determined by SERS, and why these components need to be derivatized. It provides a new method for components that are difficult to detect by SERS.

Both Short-term and Long-term Ozone Pollution Alters the Chemical Composition of rice Grain.

The increasing ground-level ozone (O3) is threatening food security, especially in Asian areas, where rice is one of the most important staple crops. O3 impacts on rice could be exacerbated by its spatiotemporal heterogeneity. To improve evaluation accuracy and develop effective adaptations, direct data is urgently needed. Studies on the short-term effects of O3 on rice grain, however, are lacking. Which may lead to an underestimation of the O3 impacts. Through a field experiment, we studied the responses of grain nitrogen, grain carbon, and grain protein in rice cultivars to elevated concentrations of O3 (40 ppb plus that in background air, eO3), especially examining the effects of short-term eO3 during different plant growth stages. We found that long-term eO3 increased grain nitrogen by 29.29% in a sensitive rice cultivar, and short-term eO3 at the tillering and jointing stages increased grain nitrogen by 19.31%, and the grain carbon to nitrogen ratio was decreased by 14.70%, and 21.14% by short-term and long-term eO3. Here we demonstrate that short-term eO3 may significantly affect the chemical composition of rice grains. Previous evaluations of the effects of eO3 may be underestimated. Moreover, changes in the grain nitrogen and grain protein were greater when the short-term eO3 was added to rice plants during the tillering and jointing stage, compared to heading and ripening stage. These results suggest that to improve the tolerance of rice to eO3 to achieve food security, studies on cultivar screening, as well as developing growth-stage-specific adaptations are needed in future.

Aspartate aminotransferase of Rhizobium leguminosarum has extended substrate specificity and metabolizes aspartate to enable N2 fixation in pea nodules.

Rhizobium leguminosarum aspartate aminotransferase (AatA) mutants show drastically reduced symbiotic nitrogen fixation in legume nodules. Whilst AatA reversibly transaminates the two major amino-donor compounds aspartate and glutamate, the reason for the lack of N2 fixation in the mutant has remained unclear. During our investigations into the role of AatA, we found that it catalyses an additional transamination reaction between aspartate and pyruvate, forming alanine. This secondary reaction runs at around 60 % of the canonical aspartate transaminase reaction rate and connects alanine biosynthesis to glutamate via aspartate. This may explain the lack of any glutamate-pyruvate transaminase activity in R. leguminosarum, which is common in eukaryotic and many prokaryotic genomes. However, the aspartate-to-pyruvate transaminase reaction is not needed for N2 fixation in legume nodules. Consequently, we show that aspartate degradation is required for N2 fixation, rather than biosynthetic transamination to form an amino acid. Hence, the enzyme aspartase, which catalyses the breakdown of aspartate to fumarate and ammonia, suppressed an AatA mutant and restored N2 fixation in pea nodules.

Short-term effects of ambient nitrogen dioxide on medical emergency calls for epileptic seizures: A time-series study.

Short-term exposure to air pollution has previously been studied in relation to certain neurological disorders, but there is still a lack of convincing data linking air pollution to epileptic seizures. The study's goal was to investigate how exposure to ambient nitrogen dioxide (NO2) affected the number of patients seeking assistance at the Wuhan Emergency Medical Center due to epileptic seizures. We gathered data on medical emergency calls (MECs), daily ambient air pollution concentrations (SO2, NO2, PM2.5, PM10, CO, and O3), and meteorological variables in Wuhan, China, spanning from January 1, 2017, to November 30, 2019. To investigate the potential influence of ambient nitrogen dioxide on MECs for epileptic seizures, we carried out a time-series investigation using the general additive model (GAM). Additionally, analyses stratified by season, age, and gender were performed. A total of 8989 records of MECs for epileptic seizures were enrolled in our study during the period. Statistical analysis indicates that a rise of 10 µg/m3 in NO2 concentration is linked to a 0.17% increase in daily MECs for epileptic seizures (95% confidence interval [CI]: 0.02%, 0.32%). Furthermore, people aged 14-59 years were more susceptible(2.25%, P < 0.05). The short-term effects of NO2 exposure on daily MECs for epileptic seizures were stronger in warm seasons than in cool seasons (0.55% vs. -0.10%, P < 0.0001). Our findings suggests that short-term exposure to ambient NO2 was positively correlated with daily MECs for epileptic seizures in Wuhan, China. Additionally, we observed that these associations were stronger in patients aged above 14 but under 60 years and the warmer seasons (from April to September).

Nitrogen-Doped Porous Carbons Derived from Peanut Shells as Efficient Electrodes for High-Performance Supercapacitors.

The doping of porous carbon materials with nitrogen is an effective approach to enhance the electrochemical performance of electrode materials. In this study, nitrogen-doped porous carbon derived from peanut shells was prepared as an electrode for supercapacitors. Melamine, urea, urea phosphate, and ammonium dihydrogen phosphate were employed as different nitrogen dopants. The optimized electrode material PA-1-1 prepared by peanut shells, with ammonium dihydrogen phosphate as a nitrogen dopant, exhibited a N content of 3.11% and a specific surface area of 602.7 m2/g. In 6 M KOH, the PA-1-1 electrode delivered a high specific capacitance of 208.3 F/g at a current density of 1 A/g. Furthermore, the PA-1-1 electrode demonstrated an excellent rate performance with a specific capacitance of 170.0 F/g (retention rate of 81.6%) maintained at 20 A/g. It delivered a capacitance of PA-1-1 with a specific capacitance retention of 98.8% at 20 A/g after 5000 cycles, indicating excellent cycling stability. The PA-1-1//PA-1-1 symmetric supercapacitor exhibited an energy density of 17.7 Wh/kg at a power density of 2467.0 W/kg. This work not only presents attractive N-doped porous carbon materials for supercapacitors but also offers a novel insight into the rational design of biochar carbon derived from waste peelings.

Density Functional Theory Study of Triple Transition Metal Cluster Anchored on the C2N Monolayer for Nitrogen Reduction Reactions.

The electrochemical nitrogen reduction reaction (NRR) is an attractive pathway for producing ammonia under ambient conditions. The development of efficient catalysts for nitrogen fixation in electrochemical NRRs has become increasingly important, but it remains challenging due to the need to address the issues of activity and selectivity. Herein, using density functional theory (DFT), we explore ten kinds of triple transition metal atoms (M3 = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) anchored on the C2N monolayer (M3-C2N) as NRR electrocatalysts. The negative binding energies of M3 clusters on C2N mean that the triple transition metal clusters can be stably anchored on the N6 cavity of the C2N structure. As the first step of the NRR, the adsorption configurations of N2 show that the N2 on M3-C2N catalysts can be stably adsorbed in a side-on mode, except for Zn3-C2N. Moreover, the extended N-N bond length and electronic structure indicate that the N2 molecule has been fully activated on the M3-C2N surface. The results of limiting potential screen out the four M3-C2N catalysts (Co3-C2N, Cr3-C2N, Fe3-C2N, and Ni3-C2N) that have a superior electrochemical NRR performance, and the corresponding values are -0.61 V, -0.67 V, -0.63 V, and -0.66 V, respectively, which are smaller than those on Ru(0001). In addition, the detailed NRR mechanism studied shows that the alternating and enzymatic mechanisms of association pathways on Co3-C2N, Cr3-C2N, Fe3-C2N, and Ni3-C2N are more energetically favorable. In the end, the catalytic selectivity for NRR on M3-C2N is investigated through the performance of a hydrogen evolution reaction (HER) on them. We find that Co3-C2N, Cr3-C2N, Fe3-C2N, and Ni3-C2N catalysts possess a high catalytic activity for NRR and exhibit a strong capability of suppressing the competitive HER. Our findings provide a new strategy for designing NRR catalysts with high catalytic activity and selectivity.

The TRPA1 Ion Channel Mediates Oxidative Stress-Related Migraine Pathogenesis.

Although the introduction of drugs targeting calcitonin gene-related peptide (CGRP) revolutionized migraine treatment, still a substantial proportion of migraine patients do not respond satisfactorily to such a treatment, and new therapeutic targets are needed. Therefore, molecular studies on migraine pathogenesis are justified. Oxidative stress is implicated in migraine pathogenesis, as many migraine triggers are related to the production of reactive oxygen and nitrogen species (RONS). Migraine has been proposed as a superior mechanism of the brain to face oxidative stress resulting from energetic imbalance. However, the precise mechanism behind the link between migraine and oxidative stress is not known. Nociceptive primary afferent nerve fiber endings express ion channel receptors that change harmful stimuli into electric pain signals. Transient receptor potential cation channel subfamily A member 1 (TRPA1) is an ion channel that can be activated by oxidative stress products and stimulate the release of CGRP from nerve endings. It is a transmembrane protein with ankyrin repeats and conserved cysteines in its N-terminus embedded in the cytosol. TRPA1 may be a central element of the signaling pathway from oxidative stress and NO production to CGRP release, which may play a critical role in headache induction. In this narrative review, we present information on the role of oxidative stress in migraine pathogenesis and provide arguments that TRPA1 may be "a missing link" between oxidative stress and migraine and therefore a druggable target in this disease.

Reducing Application of Nitrogen Fertilizer Increases Soil Bacterial Diversity and Drives Co-Occurrence Networks.

Reducing nitrogen fertilizer application highlights its role in optimizing soil bacterial communities to achieve sustainable agriculture. However, the specific mechanisms of bacterial community change under these conditions are not yet clear. In this study, we employed long-term field experiments and high-throughput sequencing to analyze how varying levels of nitrogen application influence the soil bacterial community structure and co-occurrence networks. The results show that reducing the nitrogen inputs significantly enhances the diversity and evenness of the soil bacterial communities, possibly due to the diminished dominance of nitrogen-sensitive taxa, which in turn liberates the ecological niches for less competitive species. Furthermore, changes in the complexity and stability of the bacterial co-occurrence networks suggest increased community resilience and a shift toward more mutualistic interactions. These findings underline the potential of reduced nitrogen application to alleviate competitive pressures among bacterial species, thereby promoting a more diverse and stable microbial ecosystem, highlighting the role of competitive release in fostering microbial diversity. This research contributes to our understanding of how nitrogen management can influence soil health and offers insights into sustainable agricultural practices.

Screening Cover Crops for Utilization in Irrigated Vineyards: A Greenhouse Study on Species' Nitrogen Uptake and Carbon Sequestration Potential.

This study examines the potential of 23 plant species, comprising 10 legumes, 9 grasses, and 4 forbs, as cover crops to enhance carbon (C) sequestration and soil nitrogen (N) in vineyards. After a 120-day evaluation period, cover crop biomass was incorporated into the soil, and grapevine seedlings were planted in its place. Among the established cover crops, the C input potential ranged from 0.267 to 1.69 Mg ha-1, and the N input potential ranged from 12.3 to 114 kg ha-1. Legume species exhibited up to threefold greater shoot dry weight (SDW) compared to grass species. Ladino white clover, Dutch white clover, and Clover blend were superior in SDW, total dry weight (TDW), total C content, and total N content. Legumes exhibited slightly higher root dry weight (RDW) than grasses, with the exception of Fall rye leading at 15 g pot-1, followed by Ladino white clover and Dutch white clover at an average of 12 g pot-1. Legumes, particularly clover blend and Alsike clover, displayed high shoot N concentration at an average of 2.95%. Root N concentration in Legumes (Fabaceae) were significantly higher at 1.82% compared to other plant families at 0.89%, while their root C/N ratio was lower at 18.3, contrasting with others at 27.7, resulting in a faster turnover. Biomass production exhibited a negative relationship (R2 = 0.51) with soil residual NO3-. Fall rye, Winfred brassica, and buckwheat had the highest N utilization efficiency (NUtE) values (ava. 121 g g-1). Alsike clover, Ladino white clover, and clover blend showed the highest N uptake efficiency (NUpE) values (ava. 75%). The Readily Available N (RAN) Reliance Index (RANRI) is introduced as a novel indicator for quantifying the extent to which a plant relies on RAN for its total N requirement. The RANRI value represents the percentage of the plant's total N sourced from RAN, ranging from 11% for legumes to 86% for grasses. This implies a substantial influx of nitrogen through a pathway independent of RAN in legumes. Grape shoot N concentration positively correlated with soil NO3- (R2 = 0.31) and cover crop C/N ratio (R2 = 0.17) but negatively correlated with cover crop TDW (R2 = 0.31). This study highlights legume plants as more effective in C and N assimilation during establishment but cautions about potential soil mineral N depletion before reaching their full biological N fixation capacity.

Effects of Water and Nitrogen on Growth, Rhizosphere Environment, and Microbial Community of Sophora alopecuroides: Their Interrelationship.

The effective management of water and nitrogen is crucial in the artificial cultivation of medicinal plants. Sophora alopecuroides, a perennial herbaceous plant in the Fabaceae family, is extensively used in medicine, with alkaloids as its primary bioactive constituents. Nevertheless, there remains a significant knowledge gap regarding how rhizospheric microbial communities respond to varying water and nitrogen conditions and their intricate relationships with soil environments and the growth of S. alopecuroides. In this study, two-year-old S. alopecuroides were used in a two-factor, three-level water-nitrogen interaction experiment. The irrigation levels included W1 (30-35% of maximum water holding capacity), W2 (50-55%), and W3 (70-75%), while nitrogen levels comprised N1 (32 mg/kg), N2 (64 mg/kg), and N3 (128 mg/kg). The study assessed plant growth indicators, total alkaloid content, and rhizospheric soil physicochemical parameters of S. alopecuroides. High-throughput sequencing (16S rRNA and ITS) was employed to analyze variations in rhizospheric microbial community composition and structure. The results showed that Proteobacteria and Ascomycota are the predominant bacterial and fungal phyla in the rhizosphere microbial community of S. alopecuroides. The highest biomass and alkaloid accumulation of S. alopecuroides were observed under the N1W3 treatment (50% nitrogen application and 70-75% of maximum water holding capacity). Specifically, six bacterial genus-level biomarkers (TRA3_20, MND1, env_OPS_17, SBR1031, Haliangium, S0134_terrestrial_group) and six fungal genus-level biomarkers (Pseudeurotium, Rhizophagus, Patinella, Pseudeurotium, Patinella, Rhizophagus) were identified under the N1W3 treatment condition. In the partial least squares path modeling (PLS-PM), water and nitrogen treatments demonstrated markedly positive direct effects on soil physicochemical parameters (p < 0.01), while showing significant negative direct impacts on alkaloid accumulation and plant growth indicators (p < 0.05). Soil physicochemical parameters, in turn, significantly negatively affected the rhizosphere fungal community (p < 0.05). Additionally, the rhizosphere fungal community exhibited highly significant negative direct effects on both the plant growth indicators and total alkaloid content of S. alopecuroides (p < 0.01). This study provides new insights into the interactions among rhizosphere soil environment, rhizosphere microbiota, plant growth, and alkaloid accumulation under water and nitrogen regulation, offering a scientific basis for the water and nitrogen management in the cultivation of S. alopecuroides.

Development of a "Signal-On" Fluorescent Aptasensor for Highly Selective and Sensitive Detection of ZEN in Cereal Products Using Nitrogen-Doped Carbon Dots Based on the Inner Filter Effect.

This study aimed to develop a novel fluorescent aptasensor for the quantitative detection of zearalenone (ZEN), addressing the limitations of conventional detection techniques in terms of speed, sensitivity, and ease of use. Nitrogen-doped carbon dots (N-CDs) were synthesized via the hydrothermal method, resulting in spherical particles with a diameter of 3.25 nm. These N-CDs demonstrated high water solubility and emitted a bright blue light at 440 nm when excited at 355 nm. The fluorescence of N-CDs was quenched by dispersed gold nanoparticles (AuNPs) through the inner filter effect, while aggregated AuNPs induced by NaCl did not affect the fluorescence of N-CDs. The aptamer could protect AuNPs from NaCl-induced aggregation, but the presence of ZEN weakened this protective effect. Based on this principle, optimal conditions for ZEN detection included 57 mM NaCl, 12.5 nM aptamer concentration, incubation of AuNPs with NaCl for 15 min in Tris-EDTA(TE) buffer, and incubation of aptamer with ZEN and NaCl for 30 min. Under these optimized conditions, the "signal-on" fluorescent aptasensor for ZEN detection showed a linear range of 0.25 to 200 ng/mL with a low detection limit of 0.0875 ng/mL. Furthermore, the developed aptasensor exhibited excellent specificity and could rapidly detect ZEN in corn flour samples or corn oil, achieving satisfactory recovery rates ranging from 84.7% to 108.6%. Therefore, this study presents an economical, convenient, sensitive, and rapid method for accurately quantifying ZEN in cereal products.

Intake of Special Amino Acids Mixture Leads to Blunted Murine Colon Cancer Growth In Vitro and In Vivo.

Cancer cells require substantial amounts of energy and substrates for their metabolic hyperactivity, enabling the synthesis of new cells at the expense of healthy ones. Preliminary in vitro data suggest that a mix of free essential amino acids (EAA-mix) can promote cancer cell apoptosis by enhancing autophagy. This study aimed to confirm, both in vitro and in vivo, whether EAA intake could influence the development of colon cancer in mice. We investigated changes in cancer proliferation in CT26 cells treated with EAA-mix and in mice fed with EAA-rich modified diets (EAARD) as compared to those on a standard laboratory diet (StD). CT26 cells were injected subcutaneously (s.c.) or intraperitoneally (i.p.). After 21 days, tumors were removed and measured. In vitro data corroborated that EAA-mix impairs cancer growth by inducing apoptosis. In vivo data revealed that mice on StD developed significantly larger (s.c.) and more numerous (i.p.) cancers than those on EAARD. EAA administration appears to influence cancer cell survival with notable antiproliferative properties.

Effects of Nitrogen Accumulation, Transportation, and Grain Nutritional Quality and Advances in Fungal Endophyte Research in Quinoa (Chenopodium quinoa Willd.) Plants.

This study aims to understand the influence of nitrogen accumulation, fungal endophyte, yield, nitrogen use efficiency, and grain nutritional quality parameters on the yield of quinoa in some areas of China. The endophytic microbial community in plants plays a crucial role in plant growth, development, and health, especially in quinoa plants under different nitrogen fertilizer levels. The results from the present study indicated that appropriate nitrogen application significantly enhanced the nitrogen accumulation and yield of quinoa grains during maturity, increasing by 34.54-42.18% and 14.59-30.71%, respectively. Concurrently, protein content, amylose, total starch, ash, and fat content also increased, with respective growth rates of 1.15-18.18%, 30.74-42.53%, 6.40-12.40%, 1.94-21.94%, and 5.32-22.22%. Our constructed interaction network of bacterial and fungal communities revealed that bacteria outnumbered fungi significantly, and most of them exhibited synergistic interactions. The moderate increase in N150 was beneficial for increasing quinoa yield, achieving nitrogen use efficiency (NUE) of over 20%. The N210 was increased, and both the yield and NUE significantly decreased. This study provides novel insights into the impact of nitrogen fertilizer on quinoa growth and microbial communities, which are crucial for achieving agricultural sustainable development.

Recent Discovery of Nitrogen Heterocycles from Marine-Derived Aspergillus Species.

Nitrogen heterocycles have drawn considerable attention because of their structurally novel and significant biological activities. Marine-derived fungi, especially the Aspergillus species, possess unique metabolic pathways to produce secondary metabolites with novel structures and potent biological activities. This review prioritizes the structural diversity and biological activities of nitrogen heterocycles that are produced by marine-derived Aspergillus species from January 2019 to January 2024, and their relevant biological activities. A total of 306 new nitrogen heterocycles, including seven major categories-indole alkaloids, diketopiperazine alkaloids, quinazoline alkaloids, isoquinoline alkaloids pyrrolidine alkaloids, cyclopeptide alkaloids, and other heterocyclic alkaloids-are presented in this review. Among these nitrogen heterocycles, 52 compounds had novel skeleton structures. Remarkably, 103 compounds showed various biological activities, such as cytotoxic, antimicrobial, anti-inflammatory, antifungal, anti-virus, and enzyme-inhibitory activities, and 21 compounds showed potent activities. This paper will guide further investigations into the structural diversity and biological activities of nitrogen heterocycles derived from the Aspergillus species and their potential contributions to the future development of new natural drug products in the medicinal and agricultural fields.