Search Results (48)

Reactive oxygen species (ROS) are critical drivers of redox-associated biogeochemical processes within the rhizosphere, yet the mechanisms of their generation under contaminant stress remain poorly understood. A 24-day pot cultivation experiment with four treatments (control, naphthalene, phenanthrene, and anthracene) was conducted to investigate how polycyclic aromatic hydrocarbons (PAHs) alter the production of three kinds of ROS (e.g., O₂^•−, H₂O₂, and ^•OH) in the maize rhizosphere. PAHs promoted the production of rhizosphere ROS, and the promotion effects were compound-dependent, following the order of anthracene > phenanthrene ~ naphthalene. The increases in O₂^•− content were 55.6%, 14.3%, and 17.9% under anthracene, phenanthrene, and naphthalene treatments. The H₂O₂ content was enhanced by 58.6% under anthracene treatment, 10.4% under phenanthrene treatment, and 15.4% under naphthalene treatment. The ^•OH concentrations increased by 62.5%, 21.1%, and 0.5% under anthracene, phenanthrene, and naphthalene exposure, respectively. Importantly, the variations in rhizosphere ROS’ content simultaneously fluctuated with stem length, photosynthetic rates, root exudates, dissolved organic carbon (DOC), water-soluble phenols, and enzymes activities induced by PAHs stress. Statistical analysis suggested PAH stress enhanced maize biomass (particularly stem growth), thereby improving photosynthetic efficiency and thus stimulating root exudate release. Root exudates could promote water-soluble phenol and DOC release and enhance microorganism reproduction, thereby mediating abiotic ROS’ production via electron transfer and biotic ROS’ production via extracellular release. These findings clarify the response of rhizosphere ROS to PAHs stress, providing valuable insights for rhizosphere-ROS-mediated remediation of soil pollutants. Full article

Squalene is a triterpene with potent biological activities. Squalene (C₃₀H₅₀) is a linear polyunsaturated hydrocarbon composed of six isoprene units and six carbon–carbon double bonds. It serves as an essential precursor for sterols, steroid hormones, and vitamin D in humans and exhibits antioxidant, anti-tumor, and lipid-regulating properties. In plants, squalene is produced via the mevalonate (MVA) and 2-C-methyl-D-erythritol-4-phosphate (MEP) pathways. The key rate-limiting enzymes in these pathways include 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), farnesyl diphosphate synthase (FPS), and squalene synthase (SQS). Camellia oleifera, a unique woody oil crop native to China, is valued for its high-quality edible oil and as a rich natural source of squalene. This review provides a systematic overview of recent progress in squalene biosynthesis in C. oleifera. It summarizes the structural characteristics and biosynthetic routes. It further elaborates on the multi-level regulatory network modulated by transcription factors (WRKY, bHLH, MYB, and ERF), phytohormones (jasmonic acid, abscisic acid, and gibberellin), and abiotic factors (light and drought). Notably, this review distinguishes earlier foundational studies from recent breakthroughs and integrates emerging progress on squalene’s non-canonical functions and pathway crosstalk. It further highlights novel regulatory mechanisms unique to C. oleifera (e.g., CoWRKY15, CoMYB1, and CoMYC2). By bridging molecular regulation with practical breeding and metabolic engineering, this review lays a solid theoretical foundation for cultivating high-squalene C. oleifera varieties. It represents a prominent innovation relative to previously published studies. Full article

Food-deceptive orchids exhibit significant phenotypic variability in floral traits. However, the diversity of their floral low-volatility and volatile organic compounds (VOCs) remains poorly understood. This study investigated floral diversity in the orchid Anacamptis longicornu across six Sardinian populations to evaluate the influence of environmental factors and colour polymorphism on low-volatility and volatile profiles. Chemical profiles of flower extracts obtained through steam distillation followed by liquid–liquid extraction were characterized using GC/MS analysis. A total of 79 compounds were identified, primarily saturated and unsaturated hydrocarbons, alcohols, ketones, aldehydes, esters, mono- and sesquiterpenes. Dominant compounds across both violet and white morphs included nonadecane, eicosane, octadecane, henicosane, and docosane. Significant chemical variability was detected among populations and between colour morphs, indicating that colour polymorphism substantially shapes floral profiles. Environmental heterogeneity also emerged as a critical driver, with populations exposed to extreme conditions exhibiting increased chemical diversity. Furthermore, greater geographical distance among populations correlated with higher dissimilarity in floral profiles. This study provides the first comprehensive characterization of floral diversity in A. longicornu, confirming that phenotypic variability extends to chemical traits in food-deceptive orchids. Our results highlight that the diversification in food-deceptive orchids arises from a combination of biotic and abiotic drivers. Full article

The Black Sea is highly vulnerable to environmental degradation, making the evaluation of contaminant transfer within its food webs essential for ecosystem protection, sustainable resource management, and human health risk assessment. Marine organisms accumulate contaminants through three main processes: bioconcentration (direct uptake from the abiotic environment), biomagnification (trophic transfer through consumption of contaminated prey), and bioaccumulation, which integrates contaminants from all exposure pathways. Despite numerous studies reporting contaminant concentrations in Black Sea waters, sediments, and biota, integrated analyses of trophic transfer within both pelagic and benthic food webs in the Romanian coastal sector remain limited. This study assessed the bioamplification of heavy metals—HMs, persistent organic pollutants—POPs (OCPs, PCBs) and polycyclic aromatic hydrocarbons—PAHs along the main pelagic and benthic food webs in the Romanian coastal sector, based on concentrations measured in representative invertebrate and fish species. The results revealed a compartment-driven contamination pattern, with the benthic food web functioning as an important reservoir and transfer pathway. Heavy metals showed variable and context-dependent trophic transfer, with selective amplification for Cu and Ni in some benthic links, trophic dilution or neutral transfer for Cd and Pb, and more consistent retention for Cr. In contrast, several PCB congeners showed clear biomagnification, particularly in benthic predator–prey relationships. PAHs displayed compound-dependent trophic transfer, with more pronounced amplification in benthic pathways. Overall, biomagnification was stronger for organic pollutants, particularly PCBs, than for heavy metals. The study contributes to two United Nations Sustainable Development Goals (SDGs): SDG 14 (Life Below Water) and SDG 12 (Responsible Consumption and Production). Full article

The Santos Estuarine System, one of the most anthropogenically impacted coastal regions in Brazil, was studied using benthic foraminiferal assemblages to determine four distinct stages of organic pollution. Predictive models combined with the Ecological Quality Status (EcoQs) index were applied to relate pollution stages to abiotic parameters (total organic carbon, mud content, and salinity variability) and organic contaminants, including aliphatic (AHs) and aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs), and coprostanol. The pollution gradient ranged from low (São Vicente Channel and Santos Bay, characterized by Ammonia tepida and medium coprostanol concentrations), to moderate (Santos Channel, with Bulimina elongata and Triloculina sp.1), high (Bertioga Channel, showing Cribroelphidium poeyanum, Paratrochammina sp.1, high levels of LABs, and TOC), and severe (Upper Estuary, marked by Ammonia sp.1 and high concentrations of PAHs and coprostanol). A linear discriminant analysis (LDA) demonstrated an overall accuracy of 70%, suggesting that the discriminant model performs reasonably well in predicting the predictive ability of foraminifera species to distinguish between areas with varying pollution status based on organic pollutants. Also, the potential use of the EcoQs index in assessing the environmental quality of a subtropical estuary subjected to organic pollution was demonstrated. Full article

This work involved the laboratory modeling of biogenic and biogenically mediated corrosion of AISI 304 stainless steel under geochemical conditions representative of the geological disposal of radioactive waste at the Yeniseisky site (Russia). Experiments with a single glucose stimulation of a microbial community sampled from a depth of 450 m established that the initial dominance of organotrophic microflora (primarily genera such as Xanthobacterium, Novosphingobium, Hydrogenophaga, and Pseudomonas) during the first stage (up to 30 days) led to the formation of a microbial biofilm. This biofilm resulted in uniform surface corrosion at a rate of up to 16 µm/year, which is more than 30 times higher than the corrosion rate in the abiotic control. This acceleration is attributed to the accumulation of microbial metabolites, including acetate, ethanol, formate, succinate, n-butyrate, and lactate. The subsequent development of chemotrophic iron- and sulfur-cycling microflora (dominated by genera such as Sideroxydans, Pseudomonas, Geobacter, Desulfuromonas, Desulfovibrio, and Desulfomicrobium) during the second stage of microbial succession (days 60–120) led to the formation of a pit density 10 times greater than that in the abiotic control. It is important to note that the maximum corrosion rates and pit densities were observed upon the addition of a mixture of glucose and sulfate. An assessment of the role of various microbial metabolites and medium components using the potentiodynamic method demonstrated that the combined presence of hydrocarbonate, sulfide, and microbial metabolites in the solution caused a more than fivefold increase in the corrosion current. Thus, the results demonstrate the complex nature of corrosion processes under conditions modeling the geological disposal of radioactive waste, where biological and abiotic factors interact, creating a synergistic effect that significantly enhances corrosion. Full article

Traditional diets based on diverse edible plants are increasingly threatened by climate change, which exposes crops to abiotic and biotic stressors such as drought, soil salinity, UV radiation, microorganisms, and insect herbivory. Understanding how these conditions influence both the nutritional and nutraceutical profiles, as well as the availability of key compounds, is essential to preserve their functional value. Piper auritum Kunth, used in Mexican gastronomy, was selected to assess two abiotic stress scenarios: drought stress (DS) and salicylic acid (SA) to simulate plant defense against pathogens and/or predators. We evaluated proximate composition, dietary fiber, total phenolics, total flavonoids, antioxidant capacity, low molecular weight carbohydrates (LMWCs), monomeric composition, and essential oil volatiles. Additionally, the simulated gastrointestinal digestion (INFOGEST) with an additional rat small-intestine extract (RSIE) revealed that both SA and DS shifted sugar distribution, especially for soluble and structural pools. SA treatment correlated with synthesis of secondary metabolites, particularly oxygenated and hydrocarbon terpenes. Both abiotic stressors modulated LMWC release during digestion, altering the distribution of sugars such as raffinose and galacturonic acid, with potential prebiotic implications. Essential oil analysis revealed stress-specific shifts in volatile composition, particularly in safrole, β-caryophyllene, and related terpenes. Beyond individual compound changes, the combined evaluation of composition, antioxidant properties, and volatile profile provides a comprehensive view of how abiotic stress can reshape the functional potential of P. auritum. To our knowledge, this is the first report on LMWC relative abundance across INFOGEST stages for a quelite species and on the integrated effect of DS and SA on its chemical profile. These findings highlight the importance of including compound release and functional traits, alongside chemical characterization, in future assessments of traditional plants under climate-related stress to safeguard their contribution to sustainable diets. Full article

Coal mining and consumption, a persistent source of global energy, pose significant occupational health risks. Through a bibliometric analysis of 562 publications (2001–2025), this review delineates the evolution from conventional metrics (mass concentration, free silica content) toward advanced characterization of mineralogical/geochemical heterogeneity and component dependent toxicity mechanisms. Evidence confirms that multiple toxic elements are enriched in the respirable fraction, with bioaccessibility critically governed by particle size, host phase, and chemical speciation. In vitro studies using simulated lungs and gastrointestinal fluids demonstrate that acidic environments significantly accelerate toxic metal dissolution, triggering oxidative stress. While the bioaccessibility of inorganic constituents has been extensively studied, that of complex organic pollutants, particularly polycyclic aromatic hydrocarbons, remains a critical knowledge gap. Oxidative stress is now recognized as a pivotal mechanism linking coal dust exposure to inflammation and genotoxic damage. Emerging abiotic toxicity indicators, such as environmentally persistent free radicals and oxidative potential, offer promising avenues for understanding and risk prediction; however, their analytical methodologies require further standardization and refinement. This review provides a scientific foundation for developing a next-generation risk assessment framework that integrates multi-dimensional coal dust characteristics, bioaccessibility, and oxidative potential, thereby guiding future research to better protect the health of coal miners. Full article

Welsh onion (Allium fistulosum L.) is a globally significant culinary vegetable with extensive cultivation and high application value. In China, Welsh onion is vulnerable to drought and strong-light stress in summer production, resulting in growth inhibition and quality decline. This study utilized LED-intelligent spectral-customized lamps to simulate high-light stress and a 10% PEG-6000 Hoagland solution to simulate drought stress. The effects of different stress treatments on the nutritional quality, volatile compounds, and mineral element composition of the edible portions were systematically analyzed. The results demonstrated that drought stress significantly promoted the accumulation of alcoholic compounds in leaf tissues while reducing the content of sulfur-containing compounds. High-light stress markedly increased the levels of hydrocarbon compounds in leaves. Sulfur-containing compounds in leaf tissues were predominantly disulfides, but under combined drought and high-light stress, their content decreased, while the proportion of trisulfides significantly increased. Volatile compounds in pseudostems were primarily composed of sulfur-containing and aldehyde compounds, yet their levels markedly declined under combined stress. Additionally, combined stress led to reductions in pyruvic acid, soluble sugars, and soluble protein content in the edible portions, while the crude fiber content increased, thereby significantly impairing nutritional quality. This study provides a scientific basis for understanding the abiotic stress response mechanisms of Welsh onion and offers valuable insights for cultivation management and quality regulation. Full article

The effectiveness of thermal treatment technologies for the remediation of soils contaminated with heavy hydrocarbons has been extensively documented in the scientific literature. In general, high-concentration crude-oil-contaminated soil is treated with high-temperature thermal desorption (HTTD) in order to achieve high remediation efficiency. However, this process has the unintended consequence of destroying soil fertility. Low-temperature thermal desorption (LTTD) represents an alternative approach that has been developed with the objective of remediating heavily crude-oil-contaminated soil in a more rapid and cost-effective manner while simultaneously enhancing soil fertility. The thermal desorption unit (TDU) was employed using both LTTD and HTTD, operating at 300 °C and 500 °C, respectively, with a 30 min residence time in the kiln. The concentration of total petroleum hydrocarbons (TPH) in both the LTTD- and HTTD-treated soils was found to be less than 1% by weight, thereby below regulatory standards. The environmental impacts of both processes were assessed using the OpenLCA software version 2.0. The HTTD process exhibited a total abiotic depletion potential (ADP) impact of 1.63 × 10⁻⁴ MJ and a global warming potential (GWP) of 414 kg CO₂-eq. In contrast, LTTD demonstrated lower impacts, with an ADP of 1.29 × 10⁻⁴ MJ and a GWP of 278 kg CO₂-eq. The transition from HTTD to LTTD resulted in a notable reduction in ADP by 20.5% and in GWP by 32.9%. The application of LTTD-treated soil coated with coke or carbonized residues has been demonstrated to serve as an effective soil amendment, with the capacity to sequester approximately 50% of organic hydrocarbon contaminants. The results of this study illustrate the potential of LTTD for not only economical and rapid soil remediation but also the enhancement of soil quality through beneficial reuse. Full article

Bioremediation is a promising strategy to remove crude oil contaminants. However, limited studies explored the potential of bacterial consortia on crude oil biodegradation in high salinity soil. In this study, four halotolerant strains (Pseudoxanthomonas sp. S1-2, Bacillus sp. S2-A, Dietzia sp. CN-3, and Acinetobacter sp. HC8-3S), with strong environmental tolerance (temperature, pH, and salinity), distinctive crude oil degradation, and beneficial biosurfactant production, were combined to construct a bacterial consortium. The inoculation of the consortium successfully degraded 97.1% of total petroleum hydrocarbons in 10 days, with notable removal of alkanes, cycloalkanes, branched alkanes, and aromatic hydrocarbons. Functional optimization showed that this consortium degraded crude oil effectively in a broad range of temperature (20–37 °C), pH (6–9), and salinity (0–100 g/L). In salt-enriched crude-oil-contaminated soil microcosms, the simultaneous treatment of bioaugmentation and biostimulation achieved the highest crude oil degradation rate of 568.6 mg/kg/d, compared to treatments involving abiotic factors, natural attenuation, biostimulation, and bioaugmentation after 60 days. Real-time PCR targeting the 16S rRNA and alkB genes showed the good adaptability and stability of this consortium. The degradation property of the constructed bacterial consortium and the engineered consortium strategy may have potential use in the bioremediation of crude oil pollution in high-salinity soil. Full article

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that pose significant environmental and health risks. These compounds originate from both natural phenomena, such as volcanic activity and wildfires, and anthropogenic sources, including vehicular emissions, industrial processes, and fossil fuel combustion. Their classification as carcinogenic, mutagenic, and teratogenic substances link them to various cancers and health disorders. PAHs are categorized into low-molecular-weight (LMW) and high-molecular-weight (HMW) groups, with HMW PAHs exhibiting greater resistance to degradation and a tendency to accumulate in sediments and biological tissues. Soil serves as a primary reservoir for PAHs, particularly in areas of high emissions, creating substantial risks through ingestion, dermal contact, and inhalation. Coastal and aquatic ecosystems are especially vulnerable due to concentrated human activities, with PAH persistence disrupting microbial communities, inhibiting plant growth, and altering ecosystem functions, potentially leading to biodiversity loss. In plants, PAH contamination manifests as a form of abiotic stress, inducing oxidative stress, cellular damage, and growth inhibition. Plants respond by activating antioxidant defenses and stress-related pathways. A notable aspect of plant defense mechanisms involves plant-derived extracellular vesicles (PDEVs), which are membrane-bound nanoparticles released by plant cells. These PDEVs play a crucial role in enhancing plant resistance to PAHs by facilitating intercellular communication and coordinating defense responses. The interaction between PAHs and PDEVs, while not fully elucidated, suggests a complex interplay of cellular defense mechanisms. PDEVs may contribute to PAH detoxification through pollutant sequestration or by delivering enzymes capable of PAH degradation. Studying PDEVs provides valuable insights into plant stress resilience mechanisms and offers potential new strategies for mitigating PAH-induced stress in plants and ecosystems. Full article

In recent years, the exploration of oil and gas in China’s Precambrian strata has garnered significant attention, leading to notable advancements in exploration play assessment. However, there is a dearth of published literature on Proterozoic source rocks’ organic sources, sedimentary environments, marine hydrochemistry, and other attributes. This study focuses on investigating potential source rocks within the Hongshuizhuang and Xiamaling Formations in the Jibei Depression of North China. A comprehensive analysis was conducted to evaluate hydrocarbon generation characteristics, using hydrocarbon biomarkers and polar compounds as geochemical indicators for precursor biota and maturity levels. The results indicate high organic matter abundance with predominantly type I-II₁ organic matter composition in the studied source rocks. These samples are at an immature–low mature stage, with the potential for primarily generating aromatic crude oil. The parent material is mainly attributed to lower aquatic organisms, such as bacteria and algae. The sedimentary environment exhibits marine facies, characterized by high evaporation rates, salinity levels, and strong euxinic conditions, that led to sulfur incorporation into the organic matter matrix. It should be noted that correlations between biomarker parameters and maturity may not be fully applicable to ancient source rocks; however, the methyldibenzothiophene ratio (MDR) demonstrates a strong correlation with Tmax. The compounds and their total monoisotope ions abundance (TMIA) were primarily identified and analyzed using FT–ICR MS. It was observed that these compounds were influenced by the depositional environment and organic matter maturity. Importantly, it was clearly demonstrated that the DBE and carbon number range of CH compounds gradually increased with maturity, due to the removal of N, S, and O functional groups. Specifically, N₁ compounds predominantly consisted of carbazoles with short alkyl side chains which readily converted into N₁O_x compounds. On the other hand, O₁ compounds mainly comprised benzofurans with low abundance, indicating a reducing sedimentary environment, as suggested by their low TMIA values. Furthermore, S₁ compounds were primarily thiophenes whose DBE range and carbon number increased with maturity, possibly suggesting an abiotic input of inorganic sulfur. Notably, the maturity indices (MAT) proved suitable for Mesoproterozoic source rocks while exhibiting strong linear relationships. Full article

Humic substances are naturally occurring materials composed of complex biogenic mixtures of substituted aromatic and aliphatic hydrocarbon core materials derived from the degradation and decomposition of dead plant and animal matter. They are ubiquitous in both terrestrial and aquatic systems constituting biotic pools and are characterized by unique properties; they are amphiphilic redox compounds with exceptional chelating features. Humic substances play a crucial role in both agriculture and the environment as carbon sequestrators, soil improvers, plant health promoters, as well as stabilizers of soil aggregates and regulators of organic/inorganic nutrients bioavailability. This review article attempts to summarize current knowledge about the molecular nature and characterization techniques employed for the study of humic substances worldwide as the chemistry of their components differs markedly and depends on natural processes, several abiotic and biotic factors, the origin of the organic matter, and their complexation with inorganic, e.g., metal-ion, compounds. This work is equally concerned with the association of humic substances with dyes, a notorious pollutant, responsible for various environmental issues generally arising from the discharge of untreated effluents into soils and water bodies. Azo dyes, in particular, negatively affect soil microbial communities, as well as plant germination and growth. The aim is to feature the potential contribution of humic substances as novel materials for environment-friendly and sustainable processes. Full article

Psidium friedrichsthalianum (Myrtaceae) is a small tree with antioxidant activity in its fruits and antimicrobial activity in its leaves and thin branches. The present study analyzed the seasonal variability in the yield and essential oil composition of a P. friedrichsthalianum population in Belém, Brazil. Essential oils were obtained by hydrodistillation and analyzed by gas chromatography (GC) coupled to mass spectrometer (MS) and flame ionization detector (FID). Chemometric analyses were carried out to verify the climatic influence on the production and composition of the essential oil. The average oil yield in the dry season (August–February) was 0.5 ± 0.0%, and in the rainy season (March–May), it was 0.8 ± 0.0%, with statistical differentiation. There was a moderate correlation between oil yield and the collection area’s relative humidity (r = 0.63). The PCA and HCA analyses did not show differentiation between the P. friedrichsthalianum oil samples during the dry and rainy seasons. However, the class of monoterpene hydrocarbons presented a negative correlation with temperature (r = −0.81) and humidity (−0.80) of the sampled area. In the PCA and HCA studies, the samples were classified into three groups: Group I (leaf oils) was characterized by a higher content of α-pinene (6.3–18.0%), β-elemene (9.9–14.8%), caryophyllene oxide (4.3–16.3%), and β-pinene (4.8–13.4%). Group II (leaf oils) was defined by a higher content of selin-11-en-4-α-ol (4.6–15.6%), β-elemene (9.9–14.8%), α-pinene (6.3–18.0%), and E-caryophyllene (3.1–8.7%). Group III (fruits volatile concentrate) was characterized by a higher content of α-pinene (17.6%), α-terpineol (13.7%), and selin-11-en-4-α-ol (10.0%). There was significant seasonal variability in P. friedrichsthalianum, whose responses are directly linked to abiotic factors such as precipitation, insolation, humidity, and temperature. Full article