Systems of oligonucleotide chemical replicator molecules provide some of the finest, empirically realizable models of prebiotic evolution. Yet, a full understanding of their eco-evolutionary implications is hampered by conflicting assumptions, modeling strategies, and therefore predictions in the literature. Here we construct a model of these systems that accounts for the reversible association of templates and copies, ultimately leading to self-inhibition and sub-exponential growth. We show that, contrary to predictions from simplified model descriptions, there are well-defined limits on the attainable diversity of different replicator species. We also demonstrate that increasing the overall concentration of the system increases diversity, but counterintuitively, an analogous increase in the available resource concentration has the opposite effect. Most notably, if an exponentially-growing replicator is also present in the system, it absorbs any increase in the total replicator concentration, while the concentrations of the sub-exponential replicators remain unchanged. In the context of prebiotic evolution, this means that in high-concentration local environments, an exponential replicator can reach disproportionately high concentrations even if its copying rate is lower than that of the sub-exponential replicators. In a variable environment, this can lead to the eventual stochastic extinction of its competitors, with the exponentially growing species taking over the community.
Japanese beetle, Popillia japonica Newman, is an invasive species that attacks many field and ornamental crops. Intercropping soybean with sorghum is suggested as a strategy to reduce the abundance of P. japonica throughout soybean fields. The mechanism by which this affects P. japonica is unknown but may arise from a difference in the host plant compounds emitted by the intercropped plants because P. japonica responds to olfactory cues. In this study, we investigated a semiochemical-based mechanism for the behavioral response of P. japonica to intercropping soybean with sorghum by (1) evaluating P. japonica behavioral responses to solvent extracts from monocropped soy, intercropped soy, and a mixture of soy and sorghum extracts in no-choice video-tracking and preference in a release-recapture dual-choice assay to host stimuli from plants; and (2) applying solid-phase microextraction (SPME) in conjunction with gas chromatography coupled with mass spectrometry (GC-MS) to characterize the semiochemical profiles of each extract. We found unique semiochemical profiles among our treatments, with 1-octen-3-ol and 1-octanol characteristic of monocropped soybean and dodecane-1-iodo primarily in sorghum extracts. Nevertheless, our treatments did not significantly affect movement or orientation by P. japonica compared to controls, nor did conspecifics exhibit a significant preference for any of the treatments in a dual-choice assay at a local scale. Therefore, if intercropping soybean with sorghum significantly affects the behavior of P. japonica in the field, it may occur at a different scale, or in response to non-olfactory stimuli (e.g., visual, habitat, or landscape cues) rather than semiochemical cues.
In evolutionary terms, chemical senses are the oldest sensory modality and play key roles in ecological functions such as orientation, foraging, and socio-sexual communication. Chemical perception encompasses olfaction, taste, and chemesthesis, and has been widely studied across vertebrates. However, these senses remain poorly documented in marine mammals, particularly cetaceans. The transition from land to water profoundly reshaped cetacean sensory systems, and for decades they were considered incapable of chemoreception, implying a complete regression. Recent studies challenge this view, suggesting a more complex and incomplete regression. In this review, we synthesize current knowledge from different perspectives, using an integrative framework. First, we examine the anatomical basis of chemoreception, identifying relevant structures enabling this process and their development across early life stages. Second, we explore genetic and molecular foundations, focusing on genes underlying the development and function of chemical receptors. Third, we review behavioural evidence, highlighting experimental studies on cetacean responses to chemical cues in ecological contexts such as predator-prey interactions, foraging, and social behaviour. This approach allows us to characterize and quantify chemosensory regression in cetaceans and confirms divergent evolutionary trajectories between odontocetes and mysticetes. We also identify key unresolved questions: (1) cetaceans appear to use social chemical signals, but the mechanisms remain unknown; (2) reliance on taste is still debated, with conflicting findings; (3) the ontogeny of chemical senses remains poorly understood; and (4) alternative chemical modalities such as chemesthesis have been largely overlooked despite hypothesis on their potential ecological importance.
Plants available to wild herbivores, especially browsers, often contain plant secondary metabolites (PSMs). Herbivores have evolved behavioral, physiological, and microbial mechanisms for avoiding and detoxifying PSMs. The detoxification limitation hypothesis suggests that herbivores can reduce toxicity by consuming a mixture of PSMs to avoid overloading a particular detoxification pathway. Although this hypothesis has been examined for smaller mammalian hindgut-fermenters, less is known about responses to PSM mixtures in wild ruminants. To assess the role of host and microbial responses to PSM composition, we used controlled feeding trials to measure voluntary dry matter and PSM intake, urinary excretion of glucuronic acid (GA, a byproduct of PSM detoxification through conjugation), and the diversity and relative abundance of gastrointestinal bacterial families in the feces of two species of captive-raised deer (Odocoileus hemionus, O. virginianus). Deer were fed five mixtures of four purified PSMs that included two same-chemical class mixtures, two different-class mixtures, and one 4-way mixture of all chemicals. Overall, we found that PSM composition had minimal effect on intake, that GA was a consistent physiological biomarker of PSM intake regardless of PSM composition, and that dietary phenolics may influence microbial communities more than monoterpenes. Our results partially conformed to the detoxification limitation hypothesis, where deer consumed less of one same-class mixture (monoterpenes) than different-class mixtures. Our results point to the complexity of the interplay between different behavioral, physiological, and microbial mechanisms that can mediate the consequences of PSMs.
Chemical cues play an important role in mammalian communication, often reflecting an individual's physiological state. Non-invasive sampling of such informative cues holds great potential for wildlife monitoring. Endangered apex predators such as big cats are elusive and challenging to monitor. While existing monitoring techniques estimate numbers or densities, they often fail to provide crucial demographic and physiological information. We adapted a headspace solid-phase field sampling technique adapted for sampling volatiles from urine and faeces of captive Bengal tigers and Indian leopards of known age and sex, and from urine of identified wild Bengal tigers of known age, sex, and reproductive status. Volatiles extracted from these samples were analysed using Thermal Desorption- Gas Chromatography-Mass Spectrometry. The random forest algorithm was used to identify compounds that might be cues for species, age, sex, and reproductive state. Species classification accuracy was consistently high with both urine (0.79 + 0.009) and scat (0.75 + 0.029) volatiles. Classification accuracy of urine volatiles was high for females and young individuals in leopards and tigers, but lower for males and old individuals. Scat volatiles performed better across groups. We also identified putative chemical markers for epilepsy and reproductive state in tigers. This study presents the first chemical characterization of tiger and leopard scats and the first sampling of tiger odours from the wild. Our simple and cost-effective method of sampling tiger and leopard odours offers a novel method of chemical fingerprinting to monitor populations in situ. Importantly, this sampling method and analytical pipeline is broadly applicable to other mammalian species for conservation and ecological studies.
Haematobia irritans (L.) (Diptera: Muscidae), commonly known as the horn fly, is one of the most economically significant ectoparasites of cattle worldwide, causing substantial losses in meat, milk, and hide production. Its management has historically relied on broad-spectrum insecticides, whose overuse has driven the emergence of resistant populations and raised environmental concerns, emphasizing the urgent need to alternative, ecofriendly control strategies. A key yet underexplored aspect of horn fly biology is behind one of its characteristic behaviors, oviposition behavior: gravid females deposit eggs almost exclusively in very fresh cattle dung, a preference that diminishes rapidly with time post-defecation. Although volatile organic compounds (VOCs) from dung are known to mediate this behavior, the biological origin of these chemical cues remains poorly characterized. This review proposes that microbial volatile organic compounds (mVOCs) produced by the cattle dung microbiota-particularly anaerobic bacteria derived from the bovine rumen-are major elicitors of horn fly oviposition behavior, constituting a transkingdom chemical signaling system. By systematically cross-referencing VOCs reported in fresh cattle dung with compounds known to elicit electrophysiological and behavioral responses in H. irritans, we identified four key semiochemicals of probable microbial origin: phenol, p-cresol, indole, and α-pinene, produced by bacterial families including Enterobacteriaceae, Clostridiaceae, Paenibacillaceae, and Lactobacillaceae. The temporal decline in dung attractiveness is proposed to reflect the succession of the microbial community from anaerobic to aerobic dominance, with a concomitant shift in the mVOC profile. This hypothesis is further supported by the observation that the early developmental stages of H. irritans harbor an anaerobe-dominated microbiota. This framework may provide opportunities for the development of environmentally friendly blends for horn fly management.
Cnidarian jellyfish-the medusa phase of medusozoans-are gaining recognition as important prey for a variety of predators in marine trophic webs. However, their traits as prey remain poorly understood. In this study, we examined the defensive traits of jellyfish, focusing specifically on cnidocyte-independent chemical defenses that serve as strategies against consumers, pathogens, and biofouling. To investigate these anti-consumer chemical defenses, we selected three sympatric jellyfish species: the hydromedusan Spirocodon saltatrix and the scyphomedusan moon jellyfish Aurelia coerulea as prey, and the scyphomedusan Japanese sea nettle Chrysaora pacifica as the predator. Using these species, we conducted feeding experiments, ablation of potential defensive organs, and analyses of compounds released by the prey. We found that: (1) in feeding experiments, S. saltatrix individuals exhibited an involution behavior, in which they strongly contracted and retracted their tentacles inside the umbrella when captured by C. pacifica, thereby escaping, whereas A. coerulea individuals were consumed without escaping; (2) a series of surgical ablation experiments indicated that the umbrella integument of S. saltatrix possesses a defensive function; (3) gas chromatography-mass spectrometry (GC-MS) analyses showed that S. saltatrix releases C8 to C9 alcohols and aldehydes when its integument is damaged; (4) behavioral experiments demonstrated that these compounds deter feeding by the predatory jellyfish; (5) these compounds inhibited biofilm formation by the sympatric bacterium Ectopseudomonas sp. isolated from sediment, indicating their antifouling role, though their effects on planktonic biofouling remain to be tested; and (6) the experimentally determined effective concentrations were higher than the bulk measured concentrations. Therefore, we hypothesize that the natural microscale concentrations of these compounds at the injured integument are sufficiently high to match the effective thresholds, suggesting that they function as defensive agents. Thus, our study demonstrates that S. saltatrix utilizes involution behavior and its integument to avoid predation. To our knowledge, this is the first report of exumbrellar integumental defense in a cnidarian jellyfish with suggestive evidence of chemical defense using oxidized derivatives of unsaturated fatty acids.
All animals produce semiochemicals (i.e., scent)-chemical cues that elicit physiological or behavioral responses in other individuals. Scent detection and discrimination is a fundamental aspect of the social system of many animal species, and is particularly important for snakes and other squamate reptiles. Snakes rely extensively on chemosensory information in most aspects of their life, and have a highly derived tongue-vomeronasal sensory system that is active when exploring novel chemical cues. While the role of non-volatile semiochemicals in snake behavior has received a great deal of attention, measuring how volatile, airborne semiochemicals influence behavior has been understudied due to methodological hurdles. To explore this knowledge gap, we developed a novel bioassay to test the ability of snakes to discriminate among airborne semiochemicals from other individuals. Initial experiments using this bioassay demonstrate that prairie rattlesnakes (Crotalus viridis) can use airborne semiochemicals to discriminate between conspecifics and heterospecifics (gopher snakes, Pituophis catenifer), but not between different conspecific individuals. We discuss the further implications of these findings, highlighting the utility of our experimental approach for addressing future questions related to the relationships between semiochemical production, perception, and social behavior.
Of the > 1000 known species of North American click beetles (Coleoptera: Elateridae), sex pheromones have only been identified from a handful of species. Here, we report the identification of 5-methylhexyl (Z)-4-decenoate as the female-produced pheromone of the elaterid Elater abruptus Say (subfamily Elaterinae), a species native to the northeastern United States. The pheromone was species-specific in the geographic region where it was tested, attracting only males of the target species. Ovipositor extracts contained a number of related esters, but only two, hexyl (Z)-4-decenoate and 5-methylhexyl (Z)-4-decenoate, elicited responses from antennae of male beetles in coupled gas chromatography-electroantennogram assays. In a field experiment, traps baited with 5-methylhexyl (Z)-4-decenoate, and those baited with the blend of that compound and hexyl (Z)-4-decenoate, captured significantly more beetles than did control traps. Hexyl (Z)-4-decenoate as a single component did not attract significant numbers of beetles. This phenomenon of the production of a number of inactive analogs and homologs of a pheromone component has been reported previously for a number of other elaterid species, and it remains unclear what purpose these apparently redundant compounds may serve.
Residual kanamycin (Kana) in water bodies threatens ecological safety and human health, driving demand for straightforward and sensitive detection tools. In this work, we present a label-free electrochemical sandwich aptasensor that achieves ultrasensitive Kana detection by synergizing split-aptamer recognition with signal amplification through flower-like gold nanostructures (AuNFs). The split aptamer fragments (SPA1/SPA2) remain separate in the absence of target, minimizing background from nonspecific folding. Upon Kana introduction, a SPA1-Kana-SPA2 ternary complex assembles on the AuNF-modified ITO electrode, providing a scaffold for intercalation of the redox indicator ferrocene-naphthalimide (FND). The consequent accumulation of FND results in a markedly enhanced differential pulse voltammetry response. The three-dimensional AuNFs offer a large electroactive surface for high-density probe immobilization and efficient electron transfer. The sensor exhibits a linear response for Kana from 5 nM to 2 μM with a detection limit of 0.2 nM (3σ/k). It also shows excellent selectivity over analogous aminoglycosides, good reproducibility, and acceptable storage stability. The aptasensor was successfully applied to the analysis of real water samples, yielding recoveries of 86.4-116.8%, consistent with HPLC-MS measurements. This work provides a sensitive, selective, and reliable platform for on-site monitoring of Kana in water.
Juniperus sabina is a dominant species in the desert and mountain ecosystems. There have been reports evaluating its chemical composition and biochemical values, however, investigation on its allelopathic effect which might facilitate its dominance remains largely unexplored, with the major responsible allelochemicals undetermined. In this study, we compared the allelopathic effects of the aqueous extract, ethanol extract, as well as the essential oil (EO) of J. sabina on seed germination and seedling growth of two receiver species, the dicot plant lettuce (Lactuca sativa) and the monocot plant ryegrass (Lolium perenne). Both the extracts and the EO exhibited significant allelopathic effects, with the EO showing the strongest inhibitory effect on the receiver plants: the IC50 values of the EO, the aqueous extract and the ethanol extract on lettuce were 0.203, 2.544 and 8.142 mg/mL, and 1.042, 4.802, and 4.898 mg/mL on ryegrass, respectively; indeed, the EO completely inhibited seed germination of both tested species at a concentration of 4 mg/mL. GC/MS analysis revealed that sabinene (40.1%) and cedrol (12.74%) were the most abundant constituents of the EO. Further bioassays simulating natural conditions confirmed that volatile organic compounds (VOCs) exerted significant inhibitory effects on seed germination and root length development of tested plants. Furthermore, the EO negatively impacted the cell division of Allium sativum, suggesting that it may disrupt the cell division process to suppress plant growth. Taken together, these results suggest that J. Sabina is capable of producing active volatile compounds with allelopathic activity to inhibit seedling growth of receiver species by interfering with the cell division process, which partly explains why it is a dominant species in the communities.
Availability and quality of vegetation are critical factors influencing herbivore nutrition and population dynamics. Fourier-transform infrared spectroscopy (FTIR) offers a promising approach to analyze herbivore diets using spectral properties of phytochemicals to identify plant items. We evaluated the potential of FTIR to identify plant taxa and parts consumed by an herbivore species. Crop contents from 236 rock ptarmigan (Lagopus muta MONTIN) individuals from Iceland, collected over nine years, were separated into pure fractions of plant taxa and parts (e.g., berries, leaves) and analyzed using FTIR in the mid-IR region (4000 -400 cm⁻¹). We classified plant taxa and parts with PCA and Random Forests (RF) based on spectral signals. FTIR revealed distinct chemical fingerprints for plant taxa and parts, consistent with previously established variation in lipids, proteins, carbohydrates, and chemical defenses. RF yielded high classification accuracy for plant parts (96.7%) and moderate accuracy for taxa (85.5%), confirming the method's reliability. FTIR overcomes limitations of traditional genetic analyses by identifying plant parts with varying nutritional quality within species. FTIR provided insights into biochemical properties of plant items but could not distinguish chemically similar items. Future research should expand spectral reference libraries combining FTIR with quantification of phytochemicals and DNA metabarcoding.
A key postulate in chemical ecology is that specialist herbivore insects have evolved abilities to tolerate chemical defenses specific to their host plants. Nevertheless, past studies have shown that this assumption does not always hold true. Identifying the compounds responsible for this occasional paradigm shift is essential for improving our understanding of plant-insect interactions, and for the development of new control strategies against specialized insect pests. In this study, we examined the relationship between the chemistry of Sinapis alba L. (Brassicales: Brassicaceae) and adult feeding in Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), i.e., a Brassicaceae specialist and major oilseed rape pest. A variation in the ability of different S. alba cultivars to resist feeding by this insect pest was exploited to identify deterrent compounds. A comparative bioassay-guided fractionation approach led to the hypothesis that sinalbin, a glucosinolate specific to S. alba and few other brassicaceous species, might deter feeding of P. chrysocephala adults. Pure sinalbin was tested at various concentrations, confirming its deterrent effect at a concentration naturally found in leaves of two-week-old plants, i.e., 15 nmol.mg- 1 FW. Such results provide new insights into host selection mechanisms of Brassicaceae specialists, i.e., that avoidance of intact glucosinolates may also contribute to preference. From an applied perspective, the identification of sinalbin as a biomarker of resistance in S. alba has the potential to guide future efforts into the development of new management strategies for oilseed rape pests such as P. chrysocephala.
This work describes a cost-effective, label-free electrochemical biosensor for detecting 8-hydroxy-2'-deoxyguanosine (8OHdG), the most abundant biomarker for evaluating oxidative DNA damage and early cancer risk. The sensor was fabricated by modifying screen-printed carbon electrodes (SPCEs) with a novel composite of magnetic multiwalled carbon nanotubes dispersed in a molecularly imprinted polypyrrole layer (OMMWCNTs@MIPy). The material was thoroughly characterized, showing enhanced electrocatalytic activity and selective recognition of 8OHdG. Analytical performance was evaluated by differential pulse voltammetry (DPV) after systematic optimization of synthesis and measurement parameters. The proposed method exhibited suitable sensitivity and excellent repeatability (average intraday RSD 2.7% and interday RSD 5.0%). High selectivity was also confirmed, with no interference from coexisting species in real samples. The device remained stable for at least 50 measurements and after three months of storage. Validation in spiked biological matrices yielded satisfactory recovery values close to 100% using external calibration. These results demonstrate that the proposed biosensor is a robust, sustainable, low-cost, and portable alternative to conventional immunoassays, suitable for sensitive and real-time monitoring of 8OHdG in nucleic acid samples.
Organophosphate flame retardants (OPFRs) are emerging contaminants increasingly detected in marine environments due to their extensive industrial use and replacement of brominated flame retardants. Their occurrence in different environmental compartments, combined with the formation of transformation products, raises concerns regarding persistence, transport, and ecological risks. However, the simultaneous determination of OPFRs and their metabolites in complex marine matrices remains analytically challenging due to their diverse physicochemical properties and low environmental concentrations. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of eight OPFRs and three transformation products in seawater, sediments, and marine algae. The method combines solid-phase extraction for aqueous samples (200 mL) with ultrasound-assisted extraction for solid matrices, followed by chromatographic separation on a C18 column and multiple reaction monitoring (MRM) detection using electrospray ionization. Optimization of chromatographic and ionization parameters enabled the reliable separation and detection of compounds with diverse physicochemical characteristics within a single analytical run. The method demonstrated excellent linearity (R2 ≥ 0.99), satisfactory recoveries (74-105%), and good precision (relative standard deviation ≤ 10%) for all target analytes. Matrix effects, assessed by post-extraction addition, ranged from 77% to 108%, indicating only moderate signal suppression or enhancement depending on matrix type. Method detection limits ranged from 0.19 to 0.40 ng/L in seawater and remained below 0.5 ng/g in sediments and algae, confirming the suitability of the method for ultra-trace analysis. The proposed analytical approach enables the simultaneous assessment of OPFRs and transformation products in both abiotic and biotic marine compartments using a single harmonized workflow. The inclusion of algae alongside seawater and sediments provides a more comprehensive understanding of contaminant distribution and potential bioaccumulation pathways in marine ecosystems. The method represents a robust, sensitive, and reliable analytical tool suitable for environmental assessment, contamination surveillance, and large-scale marine monitoring programs.
As modern populations spend the majority of their time indoors, understanding indoor microbial ecology is crucial for public health. While research has addressed abiotic pollutants, the ecological dynamics of surface-associated mycobiomes remain insufficiently understood. This study assessed fungal communities across 25 types of public facilities in South Korea to evaluate the relative influence of environmental parameters and human-driven factors. A total of 327 surface samples from six surface types (handles, tables, chairs, walls, pillars, floors) were analyzed using internal transcribed spacer (ITS) sequencing, yielding 27 million reads and 31,721 amplicon sequence variants (ASVs). Although temperature and humidity significantly correlated with airborne fungal concentration, they exerted minimal influence on community diversity and structure. Instead, the intensity of human contact with indoor surfaces emerged as a primary driver of fungal community composition. We found that the relative abundance of the human-associated genus Malassezia is strongly associated with two distinct ecological states of indoor surface mycobiomes; high-Malassezia samples exhibited significantly distinct communities (ANOSIM R = 0.217, p < 0.001) and dense co-occurrence networks among genera of potential clinical relevance, with strong correlations between Malassezia and both Aspergillus and Cladosporium (|corr| = 0.81). These Malassezia-associated patterns persisting across diverse facilities demonstrate that human-driven microbes are the primary ecological drivers of surface mycobiomes in public spaces, providing foundational evidence for human contact-based microbial assessments in public health monitoring and hygiene-conscious environment design.
Kanamycin (Kana) residues in water pose significant threats to ecosystems and human health, highlighting the need for rapid and simple on-site monitoring methods. Conventional salt-induced aggregation of gold nanoparticles (AuNPs) for colorimetric detection often suffers from limited sensitivity and poor color contrast. Herein, we report a dual-mechanism enhanced colorimetric biosensor that combines charge neutralization by positively charged Kana with charge shielding by NaCl to amplify AuNPs aggregation. This synergistic effect triggers a distinct color change from wine-red to dark blue within 3 min, enabling rapid visual and quantitative detection of Kana. The aggregation behavior of AuNPs was characterized by UV-Vis spectroscopy, transmission electron microscopy, dynamic light scattering, and Zeta potential measurements. Under optimized conditions, the sensor exhibited a linear range of 5-250 nM with a limit of detection (LOD) of 4.4 nM based on UV-Vis analysis. Smartphone-based RGB analysis achieved instrument-free quantification in the range of 0-250 nM, with an LOD of 2.3 nM. The biosensor also demonstrated excellent selectivity toward Kana against common interfering substances and was successfully applied to spiked environmental water samples, yielding recoveries of 94.69%-105.90% with RSDs below 7.34%. This work provides a rapid, sensitive, and portable platform for on-site monitoring of antibiotic contamination.
Accurate origin classification of chili powder is essential for consumer trust and regulatory compliance. In this study, combined near-infrared (NIR) spectroscopy and chemical composition analysis were integrated with machine learning to classify domestic (n = 54, Korea) and imported (n = 66, China and Vietnam) chili powder samples. Baseline analysis revealed systematic differences: domestic powders showed higher protein, calcium, and moisture contents, whereas imported samples contained more organic acids, sugars, and capsaicinoids. Using 16 NIR bands selected by the least absolute shrinkage and selection operator (LASSO), support vector machine (SVM) models achieved high accuracy, with Savitzky–Golay first derivative plus standard normal variate preprocessing yielding the best performance. The hybrid models enhanced reliability. NIR alone achieved high origin-classification accuracy in this dataset using as few as four selected bands; however, NIR combined with organic acid variables (NIR + org) consistently achieved 100% accuracy and showed improved probability reliability. Shapley additive explanation analysis showed that while O–H and C–H overtone bands drove the NIR spectral band-only models, the hybrid models emphasized organic acids and proximate components, providing clear chemical interpretability. The findings demonstrated that integrating NIR with targeted chemical variables enables robust, reliable, and interpretable origin classification, offering rapid screening and regulatory assurance.
With the phosphate fertilizer industry expanding to meet rising global demand, it generates substantial quantities of phosphogypsum (PG), a by-product with complex composition. The environmental challenges associated with long-term PG storage are becoming increasingly severe. This paper reviews the research progress and future prospects of PG from three perspectives: its compositional characteristics, pretreatment technologies and utilization. The Physicochemical characterization of PG are presented, and the correlations between various impurity components and application pathways are summarized. The characteristics and application scenarios of PG pretreatment technologies are discussed. Physical, chemical, and thermal treatment methods are found to be inadequate in impurity removal and associated with high costs. Biowashing method is recognized as a green approach with significant potential for impurity removal, and the development of "microbial-enzyme synergy" technologies and screen acid-resistant strains is required to balance cost reduction and safety. The current applications and limitations of PG in construction industry, agriculture, chemical industry and environment are summarized. Critical challenges include impurity-induced restrictions and the necessity for rigorous safety assessments in short-term (highway engineering) and long-term (artificial soil) large-scale applications. Finally, future research directions are proposed: screening acid-tolerant microorganisms, recovering high-value elements with low carbon emissions, evaluating the long-term performance of road materials, and optimizing the ecological safety of artificial soils. These efforts aim to promote the green treatment, efficient utilization and ecological recycling of PG.
Fusarium verticillioides and Aspergillus parasiticus are typical fungi of stored maize. To prevail over other organisms when competing for a substrate, fungi emit volatile organic compounds (VOCs) with different bioactivities. The aim of this study was to evaluate A. parasiticus and F. verticillioides interaction in maize grains stored in silo bags at different initial humidities (iH; 7.5% or 28%) for 28 days. For each treatment, dry grain weight loss, maize fungal infection, filamentous fungi count, ergosterol content, FB1 and AFB1 content, and VOCs were determined. In silo bags, A. parasiticus caused greater surface infection of the grains compared to F. verticillioides, both individually and in co-infection. In co-infection, the number of colony forming units (CFU/ g) of both fungi decreased at 28% of iH, while at 7.5% there was only a decrease in F. verticillioides. There was greater weight loss at 28% iH and in the presence of A. parasiticus. Fumonisin B1 decreased in co-infection. The ergosterol content increased at 28% iH. Qualitative and quantitative changes in VOCs profile were observed at different iH and according to the presence of fungi. 1-octen-3-ol, 3-octanone, methoxybenzene and 2-pentyl furan were the main VOCs identified. Of these compounds, 1-octen-3-ol reduced the growth and mycotoxin production of both fungi. The 1-octen-3-ol, along with other major VOCs, may support the natural regulatory mechanism between fungi during their interaction in maize stored in silo bags.