Amplification of benzo[a]pyrene toxicity persistence in earthworms by polystyrene nanoplastics: From organismal health to molecular responses.

Typically, nanoplastics (NPs) are contaminated before entering soil, and the impact of NPs on the biotoxicity of Persistent Organic Pollutants (POPs) they carry remains unclear. This study simulated two environmentally relevant scenarios: singular exposure of benzo[a]pyrene (BaP) in soil and exposure via NPs loading (NP-BaP). Correlation analysis and machine learning revealed that injury in earthworms exposed for 28 days was significantly associated with NPs.

Compound effect and mechanism of oxidative damage induced by nanoplastics and benzo [a] pyrene.

Nanoplastics and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soil environments. In order to objectively evaluate the toxic interaction between polystyrene nanoplastics (PS NPs) and benzo [a] pyrene (BaP), oxidative damage at the level of earthworm cells and biomacromolecules was investigated by experiments combined with molecular dynamics simulation. Studies on cells reveal that PS NPs and BaP had synergistic toxicity when it came to causing oxidative stress.

Nitrogen and sulfur co-doped carbon quantum dots as "on-off-on" fluorescence probes to detect Hg and MnO and improving the photostability of Rhodamine B.

Background: Carbon quantum dot (CQDs) are zero-dimensional carbon nanomaterials with a size of less than 10 nm CQDs are widely used in the field of ion detection by virtue of their fluorescence characteristics such as strong fluorescence intensity, good optical stability and tunable emission wavelength. Although the traditional atomic absorption method, electrochemical method and other metal ion detection methods are highly sensitive, the operation is complex, expensive and limited by the site. Therefore, we prepared the N, S-CQDs capable of detecting Hg and MnO in water with the advantages of simple operation, low cost, and direct visual signal.

Combined toxicity of micro/nanoplastics loaded with environmental pollutants to organisms and cells: Role, effects, and mechanism.

Micro/nanoplastics (MPs/NPs) are ubiquitous in the environment and living organisms have been exposed to these substances for a long time. When MPs/NPs enter different organisms, they transport various pollutants, including heavy metals, persistent organic pollutants, drugs, bacteria, and viruses, from the environment. On this basis, this paper summarizes the combined toxicity induced by MPs/NPs accumulating contaminants from the environment and entering organisms through a systematic review of 162 articles.

Novel highly selective fluorescence sensing strategy for Mercury(Ⅱ) in water based on nitrogen-doped carbon quantum dots.

In this work, a fluorescent signal-closing probe of nitrogen-doped carbon quantum dots (NCQDs) was developed for quantitative detection of mercury ions (Hg). In this detection system, the NCQDs with high quantum yield (QY, 63.80 %) were synthesized via simple hydrothermal method with Methyl Glycine Diacetic acid Trisodium Salt (MGDA) and m-phenylenediamine (MPD) as carbon and nitrogen sources.

Preparation of nitrogen-doped carbon quantum dots from chelating agent and used as fluorescent probes for accurate detection of ClO and Cr(Ⅵ).

In this study, a novel ionic sensor based on nitrogen-doped carbon quantum dots (N-CQDs) was developed for sensitive detection of hypochlorite ions (ClO) and dichromate ions (Cr(Ⅵ)) by fluorescence spectrometry. The N-CQDs was synthesized by hydrothermal method using Methyl Glycine Diacetic acid Trisodium Salt (MGDA) and Ethylenediamine (EDA) with bright blue fluorescence, high fluorescence quantum yield, abundant surface groups and good dispersion. The N-CQDs had a remarkable emission characteristic at 450 nm under the ultraviolet light of 350 nm, and the ClO and Cr(Ⅵ) ions could quantificationally quench the fluorescence of this emission band.

Degradation of a non-oxidizing biocide in circulating cooling water using UV/persulfate: Kinetics, pathways, and cytotoxicity.

In industry, isothiazolinone (a mixture containing 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and 2-methyl-4-isothiazolin-3-one (MIT), CMIT-MIT) as a non-oxidizing biocide is extensively used to control the growth of microorganisms in the circulating cooling water system, which potentially threatens the ecological environment and human health. In this work, the oxidative degradation of CMIT-MIT by UV/persulfate (PS) technology on a laboratory-scale was systematically investigated. The degradation of CMIT-MIT was greatly improved by UV/PS compared with only UV or oxidant.

Probing the biological toxicity of pyrene to the earthworm Eisenia fetida and the toxicity pathways of oxidative damage: A systematic study at the animal and molecular levels.

Pyrene (Pyr), a widely used tetracyclic aromatic hydrocarbon, enters soil in large quantities and causes environmental pollution due to its production and mining. In order to systematically study the biotoxicity of pyrene to model organisms Eisenia fetida in soil, experiments were carried out from four dimensions: animal, tissue, cell and molecule. Experimental results proved that the mortality rate increased with increasing concentration and time of exposure to pyrene, while the mean body weight and spawning rate decreased.

A Pyrene Fluorescent Probe for Rapid Detection of Ferric Ions.

The 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) is a pyrene derivative with high fluorescence characteristics and is widely used in fluorescence tracer. This study aims at investigating a simple and fast fluorescence detection method for determining the concentration of ferric ion by using PTSA, which the principle is that the fluorescence quenching of PTSA by ferric ions. Theoretical and experimental methods were adopted to deeply analyze its detection performance and characteristics.

Toxic mechanism of pyrene to catalase and protective effects of vitamin C: Studies at the molecular and cell levels.

Polycyclic aromatic hydrocarbons, distributing extensively in the soil, would potentially threaten the soil organisms (Eisenia fetida) by triggering oxidative stress. As a ubiquitous antioxidant enzyme, catalase can protect organisms from oxidative damage. To reveal the potential impact of polycyclic aromatic hydrocarbon pyrene (Pyr) on catalase (CAT) and the possible protective effect of Ascorbic acid (vitamin C), multi-spectral and molecular docking techniques were used to investigate the influence of structure and function of catalase by pyrene.

Degradation of fluorescent dye-Solvent Green 7 (HPTS) in wastewater by advanced oxidation process.

Solvent Green 7 (HPTS) is a widely used fluorescent dye. As a kind of polycyclic aromatic hydrocarbon (PAHs) derivative, HPTS would cause pollution when it is discharged into the environment. This study adopted advanced oxidation processes (UV/HO) to degrade the HPTS in aqueous solution and investigated the effects of various factors on the degradation.

Probing the single and combined toxicity of PFOS and Cr(VI) to soil bacteria and the interaction mechanisms.

Many research focused on the removal of perfluorooctane sulfonic acid (PFOS) and hexavalent chromium (Cr(VI)) in some industrial wastewater (e.g. electroplating wastewater), but few research reported the combined toxicity of PFOS and Cr(VI) to soil bacteria.

Competition and enhancement effect in coremoval of atenolol and copper by an easily regenerative magnetic cation exchange resin.

This paper aimed to investigate the removal of combined Cu and atenolol (ATL) in aqueous solution by using a newly synthesized magnetic cation exchange resin (MCER) as the adsorbent. The MCER exhibited efficient removal performance in sole, binary, pre-loading and saline systems. The adsorption kinetics of Cu and ATL fitted both pseudo-first-order and pseudo-second order model, while better described by pseudo-second order model in binary system.

Probing the interactions between carboxylated multi-walled carbon nanotubes and copper-zinc superoxide dismutase at a molecular level.

In order to evaluate the toxicity of multi-walled carbon nanotubes (MWCNTs-COOH) at a molecular level, the effect of MWCNTs-COOH on antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) was investigated using fluorescence spectroscopy, UV/vis absorption spectroscopy, circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC). By deducting the inner filter effect (IFE), the fluorescence emission spectra and synchronous fluorescence spectra indicated that there were interactions between MWCNTs-COOH and Cu/ZnSOD. Moreover, the microenvironment of the amino acid residues in the enzyme was changed slightly.

Interaction of Cu(2+), Pb (2+), Zn (2+) with trypsin: what is the key factor of their toxicity?

Heavy metals possess great endangerment to environment even human health because of their indissolubility and bioaccumulation. The toxicity of heavy metal ions (Cu(2+), Pb(2+), Zn(2+)) to trypsin was investigated by fluorescence, synchronous fluorescence, UV-vis absorption, circular dichroism (CD) spectroscopy, isothermal titration calorimetry (ITC), and enzyme activity assay. The experimental results showed that toxic effect of heavy metal ions was due to their own characteristic, rather than the electric charges of the ion.

Spectroscopic investigations on the interaction between carbon nanotubes and catalase on molecular level.

The interactions between well-dispersed multiwalled carbon nanotubes (MWCNTs) and catalase (CAT) were investigated. The activity of CAT was inhibited with the addition of MWCNTs. After deducting the inner filter effect, the fluorescence spectra revealed that the tryptophan (Trp) residues were exposed and the fluorescence intensities of CAT increased with the increase in the MWCNTs concentration.

Interaction mechanism of Trp-Arg dipeptide with calf thymus DNA.

The interaction between Trp-Arg dipetide (WR) and calf thymus DNA (ctDNA) in pH 7.4 Tris-HCl buffer was investigated by multi-spectroscopic techniques and molecular modeling. The fluorescence spectroscopy and UV absorption spectroscopy indicated that WR interacted with ctDNA in a minor groove binding mode and the binding constant was 4.

Interactions of L-Arg with calf thymus DNA using neutral red dye as a fluorescence probe.

The interaction between l-Arg and calf thymus DNA (ctDNA) in sodium acetate-acetic acid buffer (pH=4) was investigated with the use of neutral red (NR) dye as a spectral probe coupled with UV-vis absorption, fluorescence, and circular dichroism (CD) spectroscopy technique. The UV absorption spectroscopy indicated that l-Arg interacted with ctDNA via electrostatic force and the fluorescence enhancing of the DNA-NR system verified the electrostatic interaction. In addition, detectable changes in the CD spectrum of ctDNA in the presence of l-Arg indicated conformational changes in the DNA double helix after interaction with the drug.

Toxic effects of different charged metal ions on the target--bovine serum albumin.

In this work, the toxic influence of metallic ions (Na+, Cu2+, Al3+) on the serum albumin were studied by fluorescence, resonance light scattering (RLS), synchronous fluorescence, UV-vis absorption and circular dichroism (CD) spectroscopy. The experimental results indicated that ion electric charge is not the main factor affecting the structure of bovine serum albumin (BSA). Na+ made the structure of BSA tighter and hydrophobicity enhanced, which improved fluorescence intensity, while Cu2+ could react with some functional groups of BSA, making the structure of BSA looser, so that the internal hydrophobic groups such as tryptophan (Trp) and other aromatic residues were gradually exposed.

Binding of oxytetracycline to bovine serum albumin: spectroscopic and molecular modeling investigations.

The residue of the widely used veterinary drug oxytetracycline (OTC) in the environment (e.g., animal food, soils, surface water, and groundwater) is potentially harmful.

Study on the genotoxic interaction of methyl violet with calf thymus DNA.

By utilizing ultraviolet (UV)-visible absorption spectroscopy, circular dichroism (CD), resonance light scattering (RLS), and transmission electron microscope (TEM) techniques, the toxic interaction of methyl violet (MV) with calf thymus DNA (ctDNA) was investigated at the molecular level. The UV-visible absorption spectra results showed that MV intercalated into ctDNA base pairs at low MV concentrations, while MV was attached to the negative charged phosphate groups at higher concentrations and the binding constant (K(theta)(25 degrees C)) was 1.80 x 10(3) L mol(-1).

Investigation on the toxic interaction of toluidine blue with calf thymus DNA.

The gene toxic interactions of toluidine blue (TB) with calf thymus DNA (ct-DNA) were examined in vitro with UV-visible absorption spectroscopy, fluorescence spectroscopy, fluorescence polarization and circular dichroism techniques. The experimental results showed that TB interacted with ct-DNA by two binding modes. At low TB concentrations, TB intercalated into the DNA base pairs.

New strategy for the evaluation of CdTe quantum dot toxicity targeted to bovine serum albumin.

The biological toxicity of CdTe quantum dots (QDs) to bovine serum albumin (BSA) has been investigated mainly by fluorescence spectra, UV-vis absorption spectra and circular dichroism (CD) under simulative physiological conditions. Fluorescence data revealed that the quenching mechanism of BSA by CdTe QDs was a static quenching process and the binding constant is 6.05x10(3) and the number of binding sites is 0.

Side-chain oxidative damage to cysteine on a glassy carbon electrode.

In this paper, oxidative damage to the cysteine (CySH) side-chain on a glassy carbon electrode (GCE) was investigated. Voltammetric studies show that there are three anodic peaks for the oxidation of CySH, which arise from (1) the oxidation of the -SH side-chain, forming cystine (0.71 V, vs.

Composition-ratio determination of Chrome Azurol S (CAS) with Cu(2+) and research on dynamic reaction process of CAS with EDTA.

The composition-ratio of Chrome Azurol S (CAS) with Cu(2+) and dynamic reaction process of CAS with EDTA were studied by spectrophotometry. The composition-ratio of Cu(2+) with CAS (2:1) was successfully determined using the method of lines and EDTA complexing substitution. The effects of temperature, time, pH, concentration of cetyltrimethylammonium bromide (CTMAB), and concentration of Cu(2+) on the absorption spectrum were also discussed.