Modeling the quenching of fluorescence from organic matter in Amazonian soils

Tadini, Amanda Maria; Mounier, Stéphane; Milori, Débora Marcondes Bastos Pereira

doi:10.1016/j.scitotenv.2019.134067

Cited by 17 publications

(16 citation statements)

References 34 publications

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“…According to its solubility in aqueous medium, HS is usually grouped in three fractions: humic acids (HA), fulvic acids (FA) and humin (HU). In the literature several studies are reported, with the most diverse purposes, involving HA from soils, due to its great agronomic importance (dos Santos et al, 2020;Bento et al, 2020;Canellas and Façanha, 2004;da Silva et al, 2020;Nebbioso and Piccolo, 2011;Novotny et al, 2009;Senesi et al, 2003;Tadini et al, 2020;Vergnoux et al, 2011). FA also have a great influence on soil functionality, however, the amount of studies regarding FA from soils in the literature is less compared to HA.…”

Section: Introductionmentioning

confidence: 99%

“…FA plays an important role in the mobility of metal ions, affecting their distribution, toxicity, and bioavailability in soils (Tadini et al, 2020;Zhu and Ryan, 2016;Zhu et al, 2014). Thus, the study of its role in the environment is also of great value.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the study of its role in the environment is also of great value. This fraction of HS is the most reactive, and the most mobile, due to its solubility with an abundance of oxygen-functional groups, that are responsible for the high complexation capacity with metals, especially copper ions (Tadini et al, 2020;Esteves da Silva et al, 1998). Copper is an essential micronutrient for plant growth and development, but both excess and lack can be harmful (Yruela, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The chelating properties of FA can either reduce toxicity when there is an excess of copper, or prevent it from precipitating as insoluble hydroxide, which renders it inaccessible to the plant (Boguta and Sokołowska, 2020;Bertoli et al, 2016;Stevenson, 1994). Tadini et al (2020) studied the interaction of copper with FA from Amazonian Spodosols. The FA showed greater interaction and quantity of complexation sites over the soil profile than the HA obtained from the same local.…”

Section: Introductionmentioning

confidence: 99%

“…Fluorescence excitation-emission matrix (EEM) coupled to parallel factor analysis (PARAFAC) has proved to be a powerful technique to investigate the binding properties between organic matter with metallic species, and this due to the high sensitivity, low cost and low sample volume (dos Santos et al, 2020;Tadini et al, 2020;Yuan et al, 2015;Mounier et al, 2011;Stedmon and Bro, 2008). Further, because different chemical species have different fluorescence lifetimes, it is also possible to study the fluorescence quenching mechanism through time-resolved fluorescence (TRF).…”

Section: Introductionmentioning

confidence: 99%

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Fulvic acids from Amazonian anthropogenic soils: Insight into the molecular composition and copper binding properties using fluorescence techniques

Santos

Fregolente

Mounier

et al. 2020

Ecotoxicology and Environmental Safety

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Fulvic acids (FA) are one of the components of humic substances and play an important role in the interaction with metallic species and, consequently, the bioavailability, distribution and toxicity of metals. However, only a few studies have investigated these FA properties in specific environment, such as anthropogenic soils. Therefore, knowledge about FA molecular composition as well as the FA-metal interaction is essential to predict their behavior in the soil. For this reason, the aim of this study was to investigate the molecular composition of FA extracted from two sites in an anthropogenic soil (Terra Mulata), from the Amazon region, as well as their interactions with Cu(II) ions as a model. Results from 13 C NMR, infrared and elemental analysis showed that these FA are composed mostly by alkyl structures and oxygenfunctional groups, e.g., hydroxyl, carbonyl and carboxyl. The interaction with Cu(II) ions was evaluated by fluorescence quenching, in which the FA showed both high quantity of complexing sites per gram of carbon and good affinity to interact with the metal when compared with other soil FA. The results showed that the complexation capacity was highly correlated by the content of functional groups, while the binding affinity was largely influenced by structural factors. In addition, through the lifetime decay given by time-resolved fluorescence, it was concluded that static quenching took place in FA and Cu(II) interaction with the formation of a non-fluorescent ground-state complex. Therefore, this fraction of soil organic matter will fully participate in complexation reactions, thereby influencing the mobility and bioavailability of metal in soils. Hence, the importance of the study, and the role of FA in the environment, can be seen especially in the Amazon, which is one of the most important biomes in the world.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fulvic acids from Amazonian anthropogenic soils: Insight into the molecular composition and copper binding properties using fluorescence techniques

Santos

Fregolente

Mounier

et al. 2020

Ecotoxicology and Environmental Safety

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Seasonal studies of aquatic humic substances from Amazon rivers: characterization and interaction with Cu (II), Fe (II), and Al (III) using EEM-PARAFAC and 2D FTIR correlation analyses

Constantino,

Bento,

Santos

et al. 2024

Environ Monit Assess

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Development of micro-zymography: Visualization of enzymatic activity at the microscopic scale for aggregates collected from the rhizosphere

et al. 2022

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Aims Visualization of enzymatic activity links microbial functioning to localization in heterogeneous soil habitats. To assess enzymatic reactions in soil thin layer at the microscopic level, we developed a micro-zymography approach and tested it by visualization of the potential activity of phosphomonoesterase for aggregates collected from the rhizosphere of Zea mays L. Methods We evaluated micro-zymography by applying fluorogenically-labeled substrate i) on individual soil aggregates freshly sampled from the rhizosphere, ii) on thin layers of aggregates (≈ 500 µm) saturated with substrate to assess the dynamics of phosphomonoesterase activity, and iii) on maize roots under laser scanning microscope upon the identified hotspots by membrane-based zymography. Results We found super transparent silicon as the most appropriate fixative to prevent sample drying. We optimized microscope settings to eliminate the soil auto-fluorescence. The fluorescent signal shifted from the free liquid phase towards the aggregate boundaries within 30 min after substrate addition and was finally detectable at the surface of a few aggregates. This was probably due to higher microbial abundance and enzymatic activity on the soil aggregates compared to the liquid phase. The enzymatic activity appeared patchy at the aggregate and root surfaces indicating heterogeneous distribution of hotspots. Conclusions The methodology including calibration, sample preparation, fixation, and monitoring was developed. The novel membrane-free micro-zymography approach is a promising tool to identify functional specificity and niche differentiation on roots and soil aggregates. This approach revealed unexplained complexity of competing processes (biochemical, hydrolytic, and physical) due to differently charged reaction products and enzyme-clay complexes.

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Modeling the quenching of fluorescence from organic matter in Amazonian soils

Cited by 17 publications

References 34 publications

Fulvic acids from Amazonian anthropogenic soils: Insight into the molecular composition and copper binding properties using fluorescence techniques

Fulvic acids from Amazonian anthropogenic soils: Insight into the molecular composition and copper binding properties using fluorescence techniques

Seasonal studies of aquatic humic substances from Amazon rivers: characterization and interaction with Cu (II), Fe (II), and Al (III) using EEM-PARAFAC and 2D FTIR correlation analyses

Development of micro-zymography: Visualization of enzymatic activity at the microscopic scale for aggregates collected from the rhizosphere

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