CHEMOSPHERE

Enhancement of medium-chain fatty acids production from sewage sludge fermentation by zero-valent iron
Lou T, Yin Y and Wang J
The effect of zero-valent iron (ZVI) dosage on medium-chain fatty acids (MCFAs) production from sewage sludge fermentation was explored. ZVI within a dosage of 2-20 g/L favored MCFAs production. Adding 20 g/L ZVI (ZVI20) increased the MCFAs and long-chain alcohols (LCAs) production to 4079.0 mg/L and 93.1 mg/L, the electron transfer efficiency of MCFAs and MCFAs selectivity were also increased by over 40% and 25% than the control. This may be due to the enriched MCFAs-producing genera, like Romboutsia and Paraclostridium. 2 g/L ZVI favorably strengthened the RBO pathway and facilitated intracellular electron generation. Moreover, ZVI facilitated the extracellular electron transfer, and cytochrome C was most enriched by ZVI20. The low MCFAs production in the ZVI50 group might be due to the inhibition of acetyl-CoA and ATP synthesis. These results provided a deep insight into the effects of ZVI dosage on MCFAs production and the specific mechanisms.
Lignocellulosic carbon sheets-based hybrid electrochemical sensor for ultra-sensitive detection of chloramphenicol
Nehru R, Gnanakrishnan S, Chen CW and Dong CD
Efficient detection of chloramphenicol (CAP) in the environment and food products is crucial for addressing global health and environmental safety concerns. This study presents the development of a cost-effective hybrid electrocatalyst comprising lignocellulosic carbon sheets, graphene oxide, and manganese oxide (LCSs/GO@MnO) for CAP detection using a simple electrochemical sensor fabricated on a glassy carbon electrode (GCE) substrate. The synergistic interaction between LCSs, GO, and MnO enhance the electroactive surface area of GCE, facilitating effective dispersion and electrode modification. This composite material significantly improves electrical conductivity and provides numerous electroactive sites for electrochemical CAP detection via voltammetric techniques. The developed sensor demonstrates a rapid electron transfer rate, enhancing electrode sensitivity for CAP detection at a low overpotential (-0.5717 V) and an optimal pH (7.0). The sensor exhibits a wide linear range (0.017-477.247 μM), excellent sensitivity (105.22 μA μM cm), and a low limit of detection (1.2 nM) with enhanced charge carrier efficiency. Additionally, the sensor shows good cycle stability, reproducibility, selectivity, and trace-level CAP sensing applicability in food samples at a low cost. These features make the sensor a promising platform for monitoring antibiotics in various applications.
Melamine - a PMT/vPvM substance as a generic indicator for anthropogenic activity and urbanisation? An explorative study on melamine in the water cycle and soil
Warner W and Licha T
Melamine has a high production volume today and is spread ubiquitously in the anthropogenic technosphere. It is released steadily to the water cycle by many sources. Even though melamine has low direct toxicity, chronic exposure can cause nephrolithiasis and disrupt the endocrine system. Most data on melamine are based on case studies with, when compared, partially contradictive implications. As melamine is a compound of many sources (SMS), v persistent, mobile (vPvM), and toxic (PMT) it has the potential to break through natural barriers posing a potential risk to drinking water resources. This study combines existing data with own measurements gathered through various individual monitoring campaigns with the aim to gain new insights into its environmental behaviour and hotspots. Samples from surface water bodies, groundwater, wastewater (treated, untreated), and soil samples were analysed regarding their melamine concentration via liquid chromatography coupled with tandem mass spectrometry (LC-MSMS). Besides three drinking water samples, melamine could be found in all water samples (n=632) of this study, with a maximum concentration of 1 289 ng/L in drinking water and 1 120 ng/L in groundwater. While a constant baseline melamine concentration with an event-based release could be observed in most surface water bodies, higher concentrations towards Western Europe (urbanisation and chemical industry) was observed for wastewater. A similar pattern was found in the spatial distribution of melamine in agricultural soils towards an urban/suburban area, as some pesticides can function as precursors for melamine. As, in general, melamine concentrations were higher towards urbans centres melamine can also be classified as an indicator of anthropogenic activity and urbanisation, but also spotlights on these areas as hotspots for potentially many compounds of the human technosphere. We call policy to shift from the existing one-size-fits-all solution to more flexible and risk-based approaches to prepare for future challenges.
Tracing PAH emissions from leisure boats in a low tidal coastal area, including comparison with Environmental Quality Standards (EQS)
Nordberg K, Björk G, Abrahamsson K, Josefsson S and Lundin L
The approximately 850,000 recreational boats in Sweden, has shown to have a significant impact on the marine environment of the Swedish west coast. The extensive weather-protected archipelagos and fjords with minor tidal activity, offers excellent conditions to uncover traces of leisure boats exhaust from the background. In this study we focus on polycyclic aromatic hydrocarbons (PAHs) from boat exhausts in surface sediments and water (using SPMD) in a busy harbour and a pristine fjord. The PAH analyses were performed using gas chromatography - mass spectrometry after suitable extraction procedures. Concentrations of total PAHs in water and sediments was 4-8 ng/L and 200-5500 ng/g respectively. In addition to PAH measurements, we used the number of documented motorboat passages together with residence time of water, to quantify the concentration enhancement of up to 40% due to recreational boating. Here we have for the first time succeeded in distinguishing the leisure boat PAH signature in coastal marine environments. This by combining our data and observed compositions from lakes where emissions from leisure boats is documented as a dominating source of pollution. Comparisons with Environmental Quality standards (EQS) showed elevated levels of up to more than five times in the most exposed sediments, while the water concentrations were below the EQS. The study concludes that boating activities significantly contribute to PAH-levels in these coastal environments, with implications for environmental management and pollution mitigation strategies.
Microbial function matters: Microbiome-aware nano-ecotoxicology needs functional endpoints besides compositional data
Ouwehand J, Peijnenburg WJGM and Vijver MG
The microbiome provides an active barrier to the external environment and aids in the metabolism of the host. Nanomaterials are known to interact with this microbiome host plane. Given the recent advances in techniques to study the microbiome, there has been a vast increase in studies trying to find causality in host response via the microbiome in nano-ecotoxicology. Our review integrates the latest advancements in understanding the microbiome's role in elucidating host health related to nanomaterial exposure, thereby explicitly emphasizing the gap between compositional and functional studies. Both the techniques used to interfere and the current understanding of microbiome-host relationships in nano-ecotoxicology are discussed. To further highlight the functional side of the microbiome, we performed an explorative meta-analysis to bridge the gap between top-down and bottom-up studies. This review gives a perspective on generalising microbiome-aware nano-ecotoxicology and discusses methodologies to enhance the interpretation of nanomaterial or chemical exposure to host-microbiome interactions. The current study discloses that correlations built on compositional data are not a good proxy for host outcome and more in-depth analysis coupled with functional analysis should be explored more in microbiome-aware nano-ecotoxicology.
Thermal modulation of insecticide-induced hormetic and oxidative responses in insect pests
Silva APN, Andrade ES, Nascimento VL and Haddi K
Environmental global changes are dramatically affecting agroecosystems. Insects have been shown to present various responses to multi-stress conditions (i.e., increase in temperature and exposure to contaminants). However, there is a knowledge gap on how temperature can modulate the hormetic effects in individuals sublethally exposed to chemical stressors. Here, we investigated how temperature (15, 20, 25, and 28 ºC) modulates the effects of lethal and sublethal exposure to insecticides (imidacloprid) on the longevity, fecundity, and oxidative stress of a pest insect, the aphid Mysus persicae. Our results showed additive and interactive effects of temperature and insecticide on the stimulatory and oxidative responses of the insect pest. Overall, imidacloprid was 2.4-fold less toxic at 15 ºC (3.547 μg/ml) than at 20 ºC (1.482 μg/ml) and 24.6 to 19.8-fold less toxic than at 25 ºC (0.144 μg/ml) and 28 ºC (0.179 μg/ml) respectively. Furthermore, although the exposure of female aphids to most sublethal concentrations resulted in a decrease in their longevity and fecundity compared to the control, some of the sublethal concentrations produced positive effects in these parameters for the exposed individuals. The magnitude of induced sublethal effects varied between temperatures and occurred in similar ranges of low concentrations at temperatures 15 °C and 20 °C, and at temperatures 25 °C and 28 °C. Additionally, imidacloprid low concentrations induced a temperature-dependent production of reactive oxygen species in exposed insects at 12 and 24 hours after exposure indicating oxidative stress. Our study supplies valuable data on how temperature modulates pesticide-mediated hormesis that can alter ecological interactions and functions within agroecosystems with potential implications in pest management.
Effects of energetic compounds on soil microbial communities and functional genes at a typical ammunition demolition site
Zhu Y, Zhao S, Qi S, Zhang H, Zhang X, Li S, Wang X, Gu J, Zhang T, Xi H and Liu X
High concentrations of energetic compounds such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in military-contaminated sites pose a serious threat to human health and ecosystems. Better understanding about their effects on microbial diversity and functional genes in soil of ammunition demolition sites is required. In this study, the information of soil microbial community composition was obtained by macrogenome sequencing, and the impacts of energetic compounds on microbial community structure at the level of functional genes and enzymes based on Nr (Non-Redundant Protein Sequence Database), KEGG (Kyoto Encyclopedia of Genes and Genomes), CAZy (Carbohydrate-Active En-zymes Database) and other databases were discussed. The results showed that soil microbial diversity and functional gene abundance decreased significantly with the increase of the concentrations of energetic compounds. Conversely, the relative abundance of Proteobacteria increased significantly, reaching over 80% in the heavily TNT-contaminated area near explosive-waste water pool. Furthermore, functional gene analysis indicated that Proteobacteria had an advantage in degrading energetic compounds, and thus had the potential to improve the soil quality at ammunition demolition sites. This study provides a scientific basis for the future remediation and management of contaminated soils at ammunition demolition sites, as well as for the selection of efficient degraders of energetic compounds.
A high-rate A2O bioreactor with airlift-driven circulation and anoxic hybrid growth for enhanced carbon and nutrient removal from a nutrient rich wastewater
Rahimi Z, Zinatizadeh AA, Zinadini S, van Loosdrecht M and Batstone DJ
Within this research, a one-stage hybrid dual internal circulation airlift A2O (DCAL-A2O) bioreactor was designed and operated to simultaneously remove carbon, nitrogen and phosphorous (CNP) from milk processing wastewater (MPW) in different operational circumstances. The substantial operating variables monitored in this work were including hydraulic retention time (HRT), airflow rate (AFR) and aeration volume ratio (AVR) ranged from 7-15 h, 1-3 L/min and 0.324-0.464, respectively. From the view point of economics and process function, the optimum conditions were obtained at the HRT, AFR and AVR of 10 h, 2 L/min and 0.464, respectively. At the optimum conditions TCOD, TN, TP removal efficiencies and effluent turbidity were reported to be 97 %, 90 %, 92 % and 9 NTU, respectively. The impact of wastewater biodegradability (BOD/COD) was evaluated on the bioreactor performance using two other wastewaters i.e. soft drink (SDW) and soybean oil plant wastewaters (SOW) in comparison with the MPW. Removal efficiencies for TCOD and TN exceeding 80 % were observed. The feeding location revealed a prominent impact on the TN and phosphorous removal efficiencies (both ≥ 80 %) related to the availability degree of the readily biodegradable organic substrate to denitrifiers and PAOs. The rise in HRT, AFR and AVR resulted in reducing microbial secretions as SMP present in sludge and bioreactor effluent as well as loosely bounded EPS (LB-EPS), reported to be 26, 28, 32.5 and 194.4 mg/L TOC, respectively. Different bacteria species were present at optimum conditions confirming concurrent CNP removal in a single body. Finally, the operating cost evaluation verified the effectiveness of the hybrid airlift A2O treating the MPW.
Machine Learning Models for Quantitatively Prediction of Toxicity in Macrophages Induced by Metal Oxide Nanoparticles
Wang T, Huang Y, Zhang H, Li X and Li F
As nanotechnology advances, metal oxide nanoparticles (MeONPs) increasingly come into contact with humans. The inhaled MeONPs cannot be effectively cleared by cilia or lung mucus. In the last decade, potential immune toxicity arising from exposure to MeONPs has been extensively debated, as lung macrophage is the main pathway for cleaning inhaled exogenous particles. However, their toxicity on lung macrophages has rarely been quantitatively predicted in silico due to the complexity of responses in macrophages and the intricate properties of MeONPs. Here, machine learning (ML) methods were used to establish models for quantitatively predicting the toxicity of MeONPs in macrophages. A multidimensional dataset including 240 data points covering the lethality, biochemical behaviors, and physicochemical properties of 30 MeONPs was obtained. ML models based on different algorithms with high prediction accuracy were constructed by addressing the issue of class imbalance during the training process. The models were verified by 10-fold cross-validation and external validation. The best-performed model has an R of 0.85 and 0.90 in the 10-fold cross-validation and external test set, respectively; and Q of 0.88 and 0.90 in the 10-fold cross-validation and test set, respectively. Five parameters that impact toxicity were identified and the toxicity mechanisms were elucidated by ML analysis. The prediction results can be used to fill the data gap in the risk assessment of nanomaterials. The framework offers valuable insights for designing and utilizing safe nanoparticles, as well as aiding in decision-making processes aimed at protecting the environment and public health.
Corrigendum to "Antifouling activity and ecotoxicological profile of the cyanobacterial oxadiazine Nocuolin A" [Chemosphere 365 (2024), 143318]
Pereira S, Oliveira IB, Sousa ML, Gonçalves C, Preto M, Turkina MV, Vasconcelos V, Campos A and Almeida JR
Unveiling the green synthesis of WO nanoparticles by using beetroot (Beta vulgaris) extract for photocatalytic oxidation of rhodamine B
Anggraini F, Fatimah I, Ramanda GD, Nurlela N, Wijayanti HK, Sagadevan S, Oh WC and Doong RA
Tungsten oxide (WO) nanoparticles (WONPs) were prepared using beetroot (Beta vulgaris) extract. The synthesis was optimized by evaluating the effect of pH during the reduction of the WO precursor and sintering temperature. Physicochemical characterization of the formed nanoparticles was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance UV-visible spectroscopy. Furthermore, the prepared WONPs were employed as photocatalyst for rhodamine B removal over the photocatalytic oxidation mechanism. Synthesis optimization revealed that a single phase of WONPs obtained by reduction at pH 4 and a sintering temperature of 550°C. XRD and XPS measurements revealed that the single-phase WONPs was obtained with a crystallite size of 26.4 nm. SEM and transmission electron microscopy (TEM) indicated polymorphic forms, predominantly as nanorods, with a mean particle size of 24 nm. The WONPs have a band gap energy of 2.9 eV, supporting their performance as a photocatalyst. Evaluation of the photocatalytic activities of WONPs represents high activity and reusability of the material. A removal efficiency of 99.67% was achieved during 30 min of treatment under UV light illumination. A study on the effect of scavengers revealed the important role of hydroxy radicals in the photocatalysis mechanism. WONPs can be recycled and reused for photocatalysis, maintaining photoactivity for five cycles.
The role of habitat preference and feeding strategy on exposure to microplastic pollution in freshwater fish species
Ceylan L, Arı H and Erdoğan Ş
Microplastic (MP) pollution has been observed in a variety of ecosystems, but there is a limited number of studies on reservoir ecosystems. The aim of this study was to determine the levels of MP contamination in sediment, water and commercially important fish species (Cyprinus carpio, Perca fluviatilis, Atherina boyeri and Sander lucioperca) collected from the Yamula Reservoir in Türkiye. Water samples were collected at five stations. Four sediment samples were collected from the lake. As sediments from the lake represent a vital element of the lake ecosystem, they function as a historical archive that reflects alterations in land use and the characteristics of the lake over time. The average amounts of MPs observed in sediment and water samples were 0.12 MP/g and 0.58 MP/m respectively. The digestive systems of 30 individuals of each fish species were examined. The highest amount of MP was observed for C. carpio (6 ± 5.9 MP/individual), while the lowest amount of MP was observed for A. boyeri (1.8 ± 1.7 MP/individual). MP abundance in S. lucioperca and P. fluviatilis was 2 ± 2.8 and 4.6 ± 6.3 MP per individual. The most commonly observed polymer types were polypropylene (67%), polyvinyl alcohol (13%), polyethylene resin (13%) and high-density polyethylene (7%). The pollution load indexes determined for each fish species from the highest to the lowest were as follows: 1.83 (C. carpio) 1.6 (S. lucioperca) 1.05 (P. fluviatilis) and, 1 (A. boyeri). The findings of the study indicate that all sampling stations, including both sediment and water, are contaminated with MPs. Furthermore, the results demonstrate that all examined fish species ingest MPs. Additionally, the results indicate that fish inhabiting a wide range of habitats and consuming diverse diets are more susceptible to MP contamination.
Taloring sawdust derived hydrochar via red mud for cadmium removal: Electron transfer insight and recyclability assessment
Cui T, Chen D, Duan R, Yang F, Li D, Tian L, Zhang Y, Wang H and Xu R
Iron modified bio-adsorbents gained a lot of attention recently, especially some iron-contain wastes were employed for fabrication. However, the influence of indigenous impurities in wastes was merely investigated. In this study, red mud (RM), an iron-rich by-product was employed as source to prepare Fe modified hydrochar (RM@HC) by a facile hydrothermal method, and then employed for Cd(II) removal from wastewater. The RM@HC demonstrated excellent adsorption performance with capacity of 598.26 mg/g and maintained with a wide pH range. Further, the removal mechanisms were comprehensively elucidated and calculated, which was attributed to the various interactions include physical adsorption (29.07%), reduction (27.61%), and co-precipitation (25.81%). Moreover, the abundant metal oxides in RM@HC contributed to the removal through co-precipitation by building a highly alkaline environment. This work provided a promising choice for the sustainable reutilization of RM by designing a green bio-adsorbent to remove heavy metals from wastewater.
Solid-state fermentation of green waste for the production of biostimulants to enhance lettuce (Lactuca sativa L.) cultivation under water stress: closing the organic waste cycle
Solano Porras RC, Ghoreishi G, Sánchez A, Barrena R, Font X, Ballardo C and Artola A
Food production faces important challenges such as water scarcity and the overall need of novel sustainable strategies. This study assesses the effect of the biostimulant produced through solid-state fermentation (SSF) of green waste (wood chips and grass residues) inoculated with Trichoderma harzianum with and without L-tryptophan as a precursor for indole-3-acetic acid (IAA) production, a well-known plant hormone. The fermented solid demonstrated significant positive effects on the growth of lettuce (Lactuca sativa L.) under different irrigation conditions. Substantial enhancements were observed in growth parameters such as fresh weight, plant height, leaf area and leaf quantity, along with chemical parameters including total phenol content, chlorophylls, carotenoids, and antioxidant activity (DPPH). The results also showed a positive impact on the nutritional quality of lettuce, particularly under normal irrigation conditions. In conclusion, this study highlights the biostimulant potential to improve the yield and nutritional quality of lettuce crops by reusing plant residues. Additionally, it poses the relevance of applying circular economy principles in sustainable agriculture and organic waste management.
Biogenic Sulfide by Sulfur Disproportionation Enhances Nitrate Removal and Reduces NO Production during Sulfur Autotrophic Denitrification
Lu Z, Xu Y, Liang C, Guo W, Ngo HH and Peng L
Sulfur autotrophic denitrification (SADN) is regarded as a cost-effective bioremediation technology for nitrate-contaminated water. Nevertheless, the low bioavailability of sulfur is a major challenge that hinders nitrogen removal efficiency. A sulfur autotrophic disproportionation (SADP) process was proposed to convert sulfur to biogenic sulfide, greatly increasing the availability of electron donors. Throughout the 201-day laboratory-scale test, it was observed that the SADP process achieved desirable performance with 198.87 ± 39.8 mg S/L biogenic sulfide production per day, which could provide sufficient electron donors for the SADN process in treatment of 671.22 ± 134.40 mg N/L/d nitrate. Microbial community analysis confirmed the presence and dominancy of sulfur-disproportionating bacteria (SDB) (e.g., Desulfocaspa sp. taking up to 8.27% of the entire microbial community), while Thiobacillus was the most dominant genus of sulfur oxidizing bacteria (SOB), accounting for 87.32% of the entire community. Further experiments revealed that the addition of chemical and biogenic sulfides enhanced the nitrate removal rate of the SADN process by a factor of 1.31 and 1.34, respectively. Additionally, biogenic sulfide was found to be the most effective nitrous oxide (NO) mitigator, reducing emission by 82% and 95% in denitrification and denitritation processes, respectively. The results demonstrated that the integrated SADP and SADN processes was a more effective and carbon-neutral alternative in treatment of nitrate-contaminated water.
Corrigendum to 'Effects of dissolved organic matter from different sources on ritonavir photolysis' [Chemosphere 367 (2024) 143685]
Jia N, Shi Y, Qi J, Yang W, Bu Q, Zhao R, Yang L and Tang J
Bisphenols in Indoor Dust: A Comprehensive Review of Global Distribution, Exposure Risks, Transformation, and Biomonitoring
Moorchilot VS, Louis H, Haridas A, Praveena P, Arya SB, Nair AS, Aravind UK and Aravindakumar CT
Bisphenols (BPs) are pervasive environmental contaminants extensively found in indoor environments worldwide. Despite their ubiquitous presence and potential health risks, there remains a notable gap in the comprehensive reviews focusing on BPs in indoor dust. Existing literature often addresses specific aspects such as exposure pathways, transformation products, or biomonitoring techniques, but lacks a consolidated, in-depth review encompassing all these facets. This review provides a comprehensive overview of the global distribution of BPs, emphasizing their prevalence in diverse indoor settings ranging from households and workplaces to public areas. Variations in BP concentrations across these environments are explored, influenced by factors such as industrial activities, consumer product usage patterns, and geographical location. Exposure assessments highlight ingestion, inhalation, and dermal contact as primary pathways for BP exposure, with ingestion being particularly significant for vulnerable groups such as infants and young children. Studies consistently reveal higher concentrations of BPs in urban indoor dust compared to rural settings, reflecting the impact of urbanization and intensive consumer practices. Moreover, BPs from mobile sources like vehicles contribute significantly to overall human exposure, further complicating exposure assessments. The review also delves into the transformation of BPs within indoor environments, emphasizing the diverse roles of physical, chemical, and biological processes in generating various transformation products (TPs). These TPs can exhibit heightened toxicity compared to their parent compounds, necessitating deeper investigations into their environmental fate and potential health implications. Critical examination of biomonitoring techniques for BPs and their metabolites underscores the importance of non-invasive sampling methods, offering ethical advantages and practicality in assessing human exposure levels. The emerging use of bioindicators, encompassing plants, animals, and innovative approaches like spider webs, presents promising avenues for effectively monitoring environmental contamination.
Chlorination of Quorum Sensing Molecules: Kinetics and Transformation Pathways
Keltsch NG, Dietrich C, Wick A, Heermann R, Tremel W and Ternes TA
The impact of chlorination on quorum sensing molecules (QSMs) is not often addressed in disinfection research. Yet pathogenicity and biofilm formation are controlled by quorum sensing (QS) in many bacteria. Chemical transformation of the compounds could have an impact on all of these processes. For this reason, our study elucidated the reaction kinetics and transformation pathways of several N-acyl homoserine lactones (AHLs) and 2-heptyl-4-quinolone (HHQ) in contact with free available chlorine (FAC), a potent QS inhibitor. Both AHLs and HHQ, are known as QSMs for Gram-negative bacteria. Using FAC, a complete degradation of the target compound was observed for p-coumaroyl AHL (pC-AHL), C-AHL, HHQ and 3-Oxo-C-AHL. The reaction order for FAC varied between 1.19 (±0.07) (pC-AHL) to 1.62 (±0.13) (HHQ). This means that different reactive species (e.g. hypochlorous acid and dichlorine monoxide) are likely to be involved in the reaction mechanism. The first-order rate constants were strongly pH-dependent. For C-AHL and HHQ, the first-order rate constants decreased from pH 6.0 to pH 8.5. A maximum was observed for pC-AHL at pH 8.5 ranging from pH 6.0 to 10. In addition to the distribution of the reactive species, the phenol/phenolate ratio strongly influenced the first-order rate constants for pC-AHL. In total, at pH 7 (phosphate buffered) 29 transformation products were identified and the related transformation pathways were proposed via non-target and suspect screening of high-resolution mass spectrometry. The observed reaction mechanisms can be transferred to structurally similar QSMs to further understand QS-controlled processes during chlorination. We assumed that the transformation of the QSMs affects QS of the bacteria, thereby blocking QS-controlled processes such as biofilm formation.
New insights into uranium stress responses of Arabidopsis roots through membrane- and cell wall-associated proteome analysis
Przybyla-Toscano J, Chetouhi C, Pennera L, Boursiac Y, Galeone A, Devime F, Balliau T, Santoni V, Bourguignon J, Alban C and Ravanel S
Uranium (U) is a non-essential and toxic metal for plants. In Arabidopsis thaliana plants challenged with uranyl nitrate, we showed that U was mostly (64-71% of the total) associated with the root insoluble fraction containing membrane and cell wall proteins. Therefore, to uncover new molecular mechanisms related to U stress, we used label-free quantitative proteomics to analyze the responses of the root membrane- and cell wall-enriched proteome. Of the 2,802 proteins identified, 458 showed differential accumulation (≥1.5-fold change) in response to U. Biological processes affected by U include response to stress, amino acid metabolism, and previously unexplored functions associated with membranes and the cell wall. Indeed, our analysis supports a dynamic and complex reorganization of the cell wall under U stress, including lignin and suberin synthesis, pectin modification, polysaccharide hydrolysis, and Casparian strips formation. Also, the abundance of proteins involved in vesicular trafficking and water flux was significantly altered by U stress. Measurements of root hydraulic conductivity and leaf transpiration indicated that U significantly decreased the plant's water flux. This disruption in water balance is likely due to a decrease in PIP aquaporin levels, which may serve as a protective mechanism to reduce U toxicity. Finally, the abundance of transporters and metal-binding proteins was altered, suggesting that they may be involved in regulating the fate and toxicity of U in Arabidopsis. Overall, this study highlights how U stress impacts the insoluble root proteome, shedding light on the mechanisms used by plants to mitigate U toxicity.
Assessment of multifunctional activity of graphene oxide and guar gum-based nanomaterials against Aedes aegypti
Saya L, Samal RR, Kumar S, Verma M, Singh WR and Hooda S
Nanomaterials have been receiving much research attention in controlling insect pests and vectors. Properties, such as small surface-to-volume ratio, low dosages, durability, solubility, enhanced target activity, pore size and surface characteristics have enabled the design of precise and targeted insecticides through adsorption, encapsulation, and conjugation. The reported study aims to evaluate the efficacy of graphene oxide (GO) and guar gum (GG)-based nanomaterials against early fourth instar of Aedes aegypti, a mosquito responsible for transmitting diseases like dengue fever, Zika, and chikungunya, among many others. GO and a total of eight nanomaterials (SA-1 to SA-8) were formulated using GO, GG and their combinations with ferrous oxide and copper oxide. Each material was characterized using various biophysical techniques. The materials were evaluated for larvicidal potential by assessing their efficacy on the survival and morphology of Ae. aegypti, while the contact irritancy activity focused on determining their irritant properties upon direct exposure to the female adults. The larvicidal and irritant bioassays, conducted with these nanomaterials at different concentrations, demonstrated concentration-dependent mortality and significant behavioral responses. The exposures with nanomaterials also resulted in a deposition of black soot on the larval cuticle. The most effective nanomaterial was found as ferrous oxide nanomaterial which induced 100% larval mortality as well as significant contact irritancy. The results indicate the potential use of GO and GG-based nanomaterials against Ae. aegypti after concentration optimization.
Exploring Strategies for Kitchen Waste Treatment and Remediation from the Perspectives of Microbial Ecology and Genomics
Gu Z, He L, Liu T, Xing M, Feng L and Luo G
Nowadays, the rapid growth of population has led to a substantial increase in kitchen waste and wasted sludge. Kitchen waste is rich in organic matter, including lignocellulose. Synergistic treatment involving kitchen waste and wasted sludge can enhance treatment process. Vermicomposting can facilitate microbial activities on organic matter. Nevertheless, the underlying mechanisms remain unclear. In this study, metagenomics was used to analyze microbial functional genes in vermicomposting. Redundancy analysis found that TOC, TN and DTN adversely affect earthworm growth and reproduction. The relative abundance of Bacteroidetes and Firmicutes were increased with earthworms, thereby potentially augmenting lignocellulose degradation. The predominant functional genes included amino acid, carbohydrate, and inorganic ion conversion and metabolism. Metagenomics analysis demonstrated that GH1, GH3, GH5, GH6, GH9, GH12, GH44, GH48 and GH74, GT41, GT4, GT2, and GT51 were dominant. Furthermore, there was higher abundance of carbohydrate-active enzymes in the vermicomposting, particularly during the later phases (30-45 days). Co-occurrence network revealed that Cellvibrio in the vermicomposting exhibited a relatively dense positive correlation with other microbial groups. The findings elucidated the mechanism of vermicomposting as a promising approach for managing kitchen waste and wasted sludge.