Comparing the influence of humic/fulvic acid and tannic acid on Cr(VI) adsorption onto polystyrene microplastics: Evidence for the formation of Cr(OH)3 colloids

Microplastics (MPs) can act as vectors for various contaminants in the aquatic environment. Although some research has investigated the adsorption characteristics and influencing factors of metals/organic molecules on MPs, the effects of dissolved organic matter (DOM) (which are ubiquitous active species in ecosystems) on metal oxyanions such as Cr(VI) capture by MPs are largely unknown. This study explored the adsorption behaviors and mechanisms of Cr(VI) oxyanions onto polystyrene (PS) MPs using batch adsorption experiments and multiple spectroscopic methods. The effects of representative DOM components (i.e., humic acid (HA), fulvic acid (FA) and tannic acid (TA)) on Cr(VI) capture by PS were particularly studied. Results revealed a significantly enhanced adsorption of Cr(VI) on PS in the presence of TA. The Cr(VI) adsorption capacity was increased from 2876 μg g^-1 to 4259 μg g^-1 and 5135 μg g^-1 when the TA concentrations raised from 0 to 10 and 20 mg L^-1, respectively. Combined microscopic and spectroscopic investigations revealed that Cr(VI) was reduced to Cr(III) by TA and formed stable Cr(OH)₃ colloids on PS surfaces. Contrarily, HA and FA inhibited Cr(VI) adsorption onto PS, especially at pH > 2.0 and higher DOM concentrations, due to site competition and electrostatic repulsion. Increase in pH was found to reduce zeta potentials of MPs, resulting in inhibited Cr(VI) adsorption. The adsorbed Cr(VI) declined with increasing ionic strength, implying that outer-sphere surface complexation affected the adsorption process in the presence of DOM. These new findings improved our fundamental understanding of the fate of Cr(VI) and MPs in DOM-rich environmental matrices.

Synthesis and pharmacological characterization of multiply substituted 2H-chromene derivatives as P2Y6 receptor antagonists

P2Y6 receptor (P2Y6R) antagonists represent potential drugs for treating cancer, pain, neurodegeneration, asthma, diabetes, colitis and other disorders. However, there are few chemical classes of known competitive antagonists. We recently explored the structure activity relationship (SAR) of 2H-chromene derivatives as P2Y6R antagonists of moderate affinity. New analogues in this series modified at five positions were synthesized and shown to antagonize Ca2+ transients induced by the native agonist UDP in human (h) P2Y6R-expressing (but not turkey P2Y1R-, hP2Y2R- or hP2Y4R-expressing) astrocytoma cells. Alternatives to the reported 2-(trifluoromethyl)- and 3-nitro- substitutions of this scaffold were not identified. However, 6‑fluoro 11 and 6‑chloro 12 analogues displayed enhanced potency compared to other halogens, although still in the 1 - 2 µM range. Similar halogen substitution at 5, 7 or 8 positions reduced affinity. 5- or 8‑Triethylsilylethynyl extension maintained hP2Y6R affinity, with IC50 0.46 µM for 26 (MRS4853). The 6,8‑difluoro analogue 27 (IC50 2.99 µM) lacked off-target activities among 45 sites examined, unlike earlier analogues that bound to biogenic amine receptors. 11 displayed only one weak off-target activity (σ2). Mouse P2Y6R IC50s of 5, 25, 26 and 27 were 4.94, 17.6, 6.15 and 17.8 µM, respectively, but most other analogues had reduced affinity (>20 µM) compared to the hP2Y6R. These analogues are suitable for evaluation in in vivo inflammation and cancer models, which will be performed in the future studies.

A synthetically benign one-pot construction of enamino-xanthene dyes

Polyhydroxylated phenols are components of biomass and precursors of pigments in plants. This paper reports a novel entry to xanthene dyes, involving the reaction of 2,4,6-trihydroxybenzaldehyde with primary aliphatic amines. This catalyst-free synthesis exhibits a high atom economy and can be conducted under eco-friendly conditions and operational simplicity.

Stimuli-Responsible SNARF Derivatives as a Latent Ratiometric Fluorescent Probe

Fluorescence imaging is a powerful technique for continuous observation of dynamic intracellular processes of living cells. Fluorescent probes bearing a fluorescence switching property associated with a specific recognition or reaction of target biomolecule, that is, stimuli-responsibility, are important for fluorescence imaging. Thus, fluorescent probes continue to be developed to support approaches with different design strategies. When compared with simple intensity-changing fluorescent probes, ratiometric fluorescent probes typically offer the advantage of less sensitivity to errors associated with probe concentration, photobleaching, and environmental effects. For intracellular usage, ratiometric fluorescent probes based on small molecules must be loaded into the cells. Thus, probes having intrinsic fluorescence may obscure a change in intracellular signal if the background fluorescence of the remaining extracellular probes is high. To overcome such disadvantages, it is necessary to minimize the extracellular background fluorescence of fluorescent probes. Here, the design strategy of the latent ratiometric fluorescent probe for wash-free ratiometric imaging using a xanthene dye seminapthorhodafluor (SNARF) as the scaffold of fluorophore is discussed.

Coinage Metal-Catalyzed Asymmetric Reactions of ortho-Alkynylaryl and Heteroaryl Aldehydes and Ketones

Coinage metals have become the metal of choice due to their excellent catalytic activity in organic transformation processes. Combining various chiral ligands and coinage metals became a productive area of research and access to heterocyclic derivatives according to an efficient and sustainable manner. This review was devoted to the various recently developed coinage metal-catalyzed domino processes of ortho-alkynylaryl and heteroaryl aldehydes and ketones leading to functionalized heterocycles. Various gold chiral complexes were presented, and methods of preparations of chromenes along with indoles were covered. Ag-chiral complexes are also prone to interesting activities such as cyclization followed by reduction and functionalization with enolizable ketones or (diazomethyl)phosphonate. Asymmetric Cu-catalyzed domino cyclization and asymmetric transfer hydrogenation reactions efficiently led to functionalized chromenes. Some remarkable examples involving copper associated with ruthenium in the context of a cyclization and asymmetric hydrogenation process were also presented.

A novel class of xanthene dyes with chemically linked UV absorber molecule and their photophysical properties

In this paper, we prepared a new class of chemically linked UV absorber XU2 & XU3, and their photophysical, chemical properties and substrate durability were investigated. Spectroscopic behavior at various solvent and pH levels for this dye solution has been evaluated. Successfully designed an open ring form of xanthene moiety, linked a UV absorber to it, and made XU2 & XU3 that have shown good absorbance and emission band maxima at all solvents and pH mediums. Further, the found UV-Vis absorbance band maxima (λ_max), PL emission maxima (λ_em), molar extinction coefficient (ε_max) and Stokes shifts (ΔνST) when compared to commercially available dye 1. The synthesised XU2 & XU3 have shown brilliant results from exposed UV light at irradiation processing time, due to the light energy passes through the molecule by keto-enol tautomerisation between phenolic hydrogen and carbonyl carbon like a six-member ring. So it can be acted as radioless behaviour in the visible region, and it can relax the energy without any assistance. Hence, the UV absorber has protected the compound like a UV Resistance.

Kinetics of cadmium (Cd), nickel (Ni), and lead (Pb) release from fulvic acid: Role of re-association reactions and quantitative models

Dissolved organic matter (DOM), a ubiquitous ligand for heavy metals, plays a crucial role in regulating the bioavailability and fate of heavy metals in the environment. However, owing to complex structure and heterogeneity of DOM, it is still challenging to develop kinetics models to predict the rates of heavy metal reactions with DOM. In this study, we investigated the kinetics of Cd, Ni, and Pb release from a typical fulvic acid (FA) under a wide range of experimental conditions using a competing ligand exchange (CLE) method. Among three metals, Cd showed the fastest release from FA while Ni and Pb had slower release rates. Reaction pH also had different impact on the release rates of the three metals, presumably attributed to different proton/metal exchange ratios for the metal ion complexation with FA. We formulated a kinetics model for Cd, Ni, and Pb release from FA by considering metal ions dissociation from FA, re-association of metal ions with FA, and metal ion uptake by the resin in the CLE experiments. The chemical speciation model WHAM 7 was used to predict the local equilibrium status that the kinetic reactions were away from, which help to derive the kinetic parameters based on the equilibrium parameters. For both Cd and Pb, model calculations were sensitive to the re-association rates, especially at high pH, while for Ni, the impact of the re-association rates was less significant. Based on the model parameters obtained in this study, our model simulations have also demonstrated that metal-FA complexes may undergo different rates of dissociation in the environment, affecting the dynamic speciation and transfer of metals to other biological processes. This work has provided a quantitative tool for predicting metal release from DOM, which would be useful for predicting the bioavailability and fate of heavy metals in the environment.

Insight into complexation of Cd(II) and Cu(II) to fulvic acid based on feature recognition of PARAFAC combined with 2DCOS

Fulvic acid which could govern the environmental geochemistry behavior of heavy metals is considered as the eco-friendly substances for controlling heavy metal pollutants in environment. Knowledge on the individual fulvic acid ligand is crucial to characterize the effect of fulvic acid on the migration and toxicity of metal pollutants. Herein, fulvic acid substances were analyzed by fluorescence quenching associated with parallel factor analysis (PARAFAC). Three components were identified based on PARAFAC. Furthermore, two-dimensional correlation spectroscopy (2DCOS) associated with complexation model were used to elucidate the Cd(II)- and Cu(II)-binding characteristics of the individual fulvic acid ligand. The Cd(II)- and Cu(II)-binding capability and speed of different fulvic acid ligands were revealed and theoretical guidance and technical support were provided for the practical application. The Cd(II) contaminated soil could be amended with high fulvic acid ligands A1 and Y2 containing composting products and the Cu(II) contaminated soil could be amended with high fulvic acid ligands Y1, T1 and A1 containing composting products to control the pollution and improve the soil condition. Based on these excellent results, the different fulvic acid ligands-contaminants-binding properties was characterized for the theoretical supporting of environmental pollution control.

Dissipative self-assembly of a proline catalyst for temporal regulation of the aldol reaction

The spatiotemporal regulation of chemical reactivity in biological systems permits a network of metabolic reactions to take place within the same cellular environment. The exquisite control of reactivity is often mediated by out-of-equilibrium structures that remain functional only as long as fuel is present to maintain the higher energy, active state. An important goal in supramolecular chemistry aims to develop functional, energy dissipating systems that approach the sophistication of biological machinery. The challenge is to create strategies that couple the energy consumption needed to promote a molecule to a higher energy, assembled state to a functional property such as catalytic activity. In this work, we demonstrated that the assembly of a spiropyran (SP) dipeptide (1) transiently promoted the proline-catalyzed aldol reaction in water when visible light was present as fuel. The transient catalytic activity emerged from 1 under light illumination due to the photoisomerization of the monomeric, O-protonated (1-MCH⁺) merocyanine form to the spiropyran (1-SP) state, which rapidly assembled into nanosheets capable of catalyzing the aldol reaction in water. When the light source was removed, thermal isomerization to the more stable MCH⁺ form caused the nanosheets to dissociate into a catalytically inactive, monomeric state. Under these conditions, the aldol reaction could be repeatedly activated and deactivated by switching the light source on and off.

Nasal protection strategy reduces the incidence of nasal pressure injuries during nasotracheal intubation: Meta-analysis with trial sequential analysis

BACKGROUND

Nasal pressure injury is a serious problem during nasotracheal intubation. We performed this systematic review and meta-analysis to determine whether use of a nasal protection strategy (a protective dressing or a modified fixation method for the tracheal tube) reduces the incidence of nasal pressure injury during nasotracheal intubation.

METHODS

Literature searches were performed using three electronic databases. Data from each of the eligible trials were combined, and calculations were made using DerSimonian and Laird random effects models. The pooled effect estimates for nasal pressure injury were evaluated using the relative risk and 95% confidence interval, the Cochrane Q statistic, and the I2 statistic. We also performed trial sequential analysis (TSA) to assess sensitivity to prevent type I error. We separated patients into subgroups to analyze the incidence of nasal pressure injury according to whether a protective dressing or a modified fixation method for the tracheal tube was used.

RESULTS

The literature search yielded five eligible trials. Meta-analysis of these trials showed that a nasal protection strategy significantly reduced the incidence of nasal pressure injury during nasotracheal intubation (relative risk (RR) 0.34; 95% confidence interval (CI) 0.21-0.56; P < .0001; Cochrane's Q = 5.86, I2 = 32%). The TSA boundary for futility could not be calculated because of an insufficient sample size. In subgroup analysis, both methods significantly reduced the incidence of nasal pressure injury during nasotracheal intubation.

CONCLUSIONS

The findings of this meta-analysis suggest that a nasal protection strategy significantly reduces the incidence of nasal pressure injury during nasotracheal intubation. During nasotracheal intubation, the use of a protective dressing or modified fixation method for the tracheal tube can prevent to the incidence of nasal pressure injuries. However, the number of samples in our meta-analysis was too small for TSA and further studies are required.

TRIALS REGISTRATION

PROSPERO (International Prospective Register of Systematic Reviews; registration number 252091).

Increased frequency of angiotensin converting enzyme D allele in Chinese Han patients with idiopathic pulmonary fibrosis: A systematic review and meta-analysis

BACKGROUND

To explore the association between Angiotensin Converting Enzyme (ACE) insert(I)/defect(D) gene polymorphism and the susceptibility to idiopathic pulmonary fibrosis (IPF).

METHODS

Searching PubMed, EMbase, CENTRAL, MEDLINE, CBM, China National Knowledge Infrastructure, WanFang Database and VIP Chinese Science database through a computer and collect the literature from China and foreign countries published before January 22, 2022. Screen the literatures and extract data such as first author, year of publication, diagnostic criteria and gene frequency, and draw a funnel chart and perform Begg's Test and Egger's test to evaluate publication bias. The influence analysis was performed for heterogeneous results and at the same time, the trial sequential analysis (TSA) was also conducted to confirm the robustness of the meta-analysis results. Registration number: CRD42021259341.

RESULTS

There were a total of 4 literatures (4 studies conducted in the Chinese Han population), and a total of 292 IPF patients and 351 healthy controls were included in this study. The results showed that in the Chinese Han population, the ACE I/D gene polymorphism was associated with the susceptibility of IPF (D vs I: [odds ratio, OR] = 0.53, 95% confidence interval [95%CI] [0.42, 0.67], P < .00001; DD vs II: [OR] = 0.37, 95%CI [0.24, 0.57], P < .00001; DD vs II + ID:[OR] = 0.30, 95%CI [0.21, 0.43], P < .00001), and the angiotensin II (Ang Ⅱ) level of IPF patients was higher than that of the control group (mean difference [MD] = 14.29, 95%CI [11.20,17.37], P < .00001).The TSA also confirmed that D allele was closely related to the susceptibility of IPF.

CONCLUSION

In the Chinese Han population, the D allele of the ACE I/D gene polymorphism is associated with the susceptibility of IPF.

Molecular spectroscopic and molecular simulation studies on the interaction of oral contraceptive drug Ormeloxifene with CT-DNA

The interaction between oral contraceptive drug Ormeloxifene (ORM) and calf thymus DNA (CT-DNA) was studied using UV-Vis, fluorescence, circular dichroism (CD) and ¹H NMR spectral techniques under physiological buffer (pH 7.4). Competitive binding assays with ethidium bromide (EB) and Hoechst 33258, viscosity measurements, KI quenching studies, molecular docking and metadynamics simulation studies were also substantiated the spectroscopic results. ORM is found to binds in the minor groove of CT-DNA as evidenced by: (1) non-displacement of EB from EB/CT-DNA complex; (2) appreciable displacement of Hoechst 33258 from its CT-DNA complex; (3) slight alteration in the CD signal; (4) small shifts (Δδ < 0.033 ppm) without broadening in ¹H NMR signals and (5) the nearly equal extent of quenching of fluorescence of ORM by KI in the absence and presence of CT-DNA. Negative values of both enthalpy and entropy changes pointed out that the interaction between ORM and CT-DNA is governed mainly by H-bonding and van der Waals forces. Negative free energy change suggested a spontaneous interaction between ORM and CT-DNA. The free energy landscape of the binding process was computed using metadynamics simulation. The simulation study results disclosed that ORM binds to the minor groove of DNA through H-bonding and π-π stacking interactions. The results of molecular docking and simulation studies corroborate the available experimental data.

Physiology and proteomics reveal Fulvic acid mitigates Cadmium adverse effects on growth and photosynthetic properties of lettuce

Understanding the molecular mechanisms of plants in response to Cd stress is crucial for improving plants adaptation to Cd stress. Fulvic acid (FA) is an active humic substance that is often used as a soil conditioner. However, there are few reports on the role of FA against Cd stress. The aim of this study was to determine the effects of Fulvic acid on alleviation of Cd toxicity in lettuce (Lactuca sativa L) under hydroponic conditions. Our results showed that 20 μmol/L Cd stress significantly reduced photosynthetic pigment metabolism and the expression of photosynthetic apparatus-related proteins, thereby inhibiting photosynthetic electron transport, net photosynthetic rate and negatively affecting photosynthetic carbon assimilation and growth of lettuce. However, proteomic findings suggest that the application of FA can reduce the adverse effects of Cd contamination. Compared to Cd stress alone, FA significantly increased the expression of Light-harvesting proteins, reaction center and electron transport-related proteins. Further results showed that FA at 0.5 g/L reduced the uptake of Cd by the roots, resulting in a 23.5% reduction in total Cd content in lettuce. Moreover, FA enhanced S metabolism and rebuilt redox homeostasis in cells. Overall, these findings provide new insights into the mechanism of cadmium toxicity mitigation in lettuce by FA. Which is recommended as an eco-friendly tool for improving the photosynthesis performance and biomass of lettuce under Cd stress.

Study of arsenic adsorption in calcareous soils: Competitive effect of phosphate, citrate, oxalate, humic acid and fulvic acid

Arsenic (As) bio-availability in the soil is influenced by different organic and inorganic anions. In the present study, the effects of various competitive agents, including phosphate, citrate, oxalate, humic acid (HA), and fulvic acid (FA), on the adsorption of As in calcareous soils were investigated. The results revealed the presence of phosphate, citrate, and oxalate in soil has a significant impact on the arsenic retention (adsorption) in soil which increases the As bio-availability. The negative impact of the competing anions was increased at higher concentrations. The Double Site Langmuir (DSL) isotherm was best fitted to the adsorption data, which indicates that most of the As adsorbed on the low-energy surfaces (non-specific adsorption by oxides, clays, and clay-size calcite). Accordingly, in soil 1, the DSL predicted that, due to phosphate, citrate, and oxalate competition (at a concentration of 10 mM), the adsorption capacity of the high- and low-energy surfaces decreased from 86.2 to 33.5, 82.1 and 61.3 mg/kg and from 663 to 659, 335.8, and 303.5 mg/kg, respectively, Moreover, after addition of phosphate, citrate, and oxalate to the soil-As system, the Langmuir constant of high-energy surfaces decreased from 0.686 to 0.074, 0.261, and 0.301 L/mg, respectively. No regular trend was observed for the Langmuir constant of low-energy surfaces. Similarly, in soils 2, 3, and 4, the adsorption capacities of both high- and low-energy surfaces as well as the Langmuir constant of high-energy surfaces decreased by the addition of phosphate, citrate, and oxalate to the soil-As system. HA and FA did not have a significant effect on the As adsorption behavior. Phosphate, citrate, and oxalate, as interfering oxyanions, increased the As bio-availability in the calcareous soils by decreasing the As adsorption.

Stimuli-Responsive Dendritic Macromolecules for Optical Detection of Metal Ions and Acidic Vapors by the Photoinduced Electron Transfer Mechanism: Paper-Based Indicator for Food Spoilage Sensing

Visual detection of analytes has been a significant challenge in the design and development of optical chemosensors. Sensing of analytes in aqueous solution by organic molecules has encountered some issues, such as poor water solubility and quenching of optical properties. In this study, a new category of smart dendritic macromolecules was designed and synthesized by functionalization of the poly(amidoamine) (PAMAM) dendrimer with spiropyran molecules to afford a photoluminescent dendritic structure (SP-PAMAM). Smart optical sensors were prepared by physical incorporation of four different oxazolidine derivatives containing hydroxyl and nitro substituted groups into the SP-PAMAM structure. Investigation of optical properties demonstrated photoinduced electron transfer (PET) between the spiropyran end group of SP-PAMAM and oxazolidine derivatives (in a concentration of about 0.0002 M), which can result in quenching of fluorescence emission of spiropyran photoswitch in the form of merocyanine (MC). Treatment of the oxazolidine-doped SP-PAMAM samples with metal ions resulted in changes in the PET mechanism (switching on or off), as observed in the case of Fe³⁺, Pb²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Co²⁺, and Ni²⁺ by different oxazolidine derivatives through various mechanisms (increase or decrease of fluorescence emission). These smart photoluminescent dendritic macromolecules have potential applications for photodetection of metal ions in aqueous media as optical chemosensors. In addition, the smart macromolecules displayed disconnection of PET between MC and oxazolidine and also showed red fluorescence emission under acidic conditions (pH 1-5). It is due to the protonation of the MC to MCH form and demonstrates a remarkable red shift in fluorescence spectra. The pH-responsivity of smart macromolecules was used for designing a paper-based pH indicator for visual detection of spoilage in the food industry, especially in the case of milk. The prepared papers applied on cap of the milk bottles did not show any fluorescence emission in the case of fresh milk; however, a red fluorescence emission was observed after milk spoilage as a result of adsorption of acidic volatile components generated by bacterial degradation and oxidation process on the paper surface. The reported smart papers can serve as optical portable pH indicators for timely detection of spoilage in food materials, which are usable in food packaging as smart indicator tags.

Adsorption of fulvic acid on mesopore-rich activated carbon with high surface area

The loss of dissolved organic matter (DOM), especially fulvic acid (FA), from soil by rainfall and runoff will reduce soil fertility and result in water pollution of DOM. Carbon materials including biochars (BCs) and activated carbons (ACs) are widely suggested for soil remediation and carbon immobilization. However, these suggested carbon materials are dominated by micropores, and largely limiting the adsorption capacity for FA. Therefore, a mesopore-rich activated carbon (KAC) with high surface area was prepared from bamboo chips to investigate the adsorption of FA. This KAC can adsorb FA more than ACs and BCs investigated in this study and reported in previous studies not only because of the high surface area (3108 m²/g), but also the higher mesopore volume proportion (57%). The negative pH effect on adsorption performance of KAC was weaker than that on AC and BC, because of the less polarity of KAC. Moreover, KAC was favorable to adsorb FA fractions with various molecular weights, higher aromaticity and higher polarity. This study indicated that KAC was a promising adsorbent for FA, and revealed the underlying adsorption mechanism of FA on KAC, which are helpful for the carbon immobilization and pollution control in soil.

Comparison of Sample Preparation Techniques for the (-)ESI-FT-ICR-MS Analysis of Humic and Fulvic Acids

Soil organic matter (SOM) plays a key role in the global carbon and nitrogen cycles. Soil biogeochemistry is regularly studied by extracting the base-soluble fractions of SOM: acid-insoluble humic acid (HA) and acid-soluble fulvic acid (FA). Electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry (ESI-FT-ICR-MS) is commonly utilized for molecularly characterizing these fractions. Different sample preparation techniques exist for the analysis of HA and FA though questions remain regarding data comparability following different preparations. Comparisons of different sample preparation techniques here revealed that the negative-mode ESI-FT-ICR-MS analytical window can be skewed to detect different groups of molecules, with primary differences in oxygenation, aromaticity, and molecular weight. It was also observed that HA and FA from soils versus an aquatic matrix behaved very differently. Thus, we conclude that sample preparation techniques determined to be "most optimal" in our study are in no way universal. We recommend that future studies of HA and FA involve similar comparative studies for determining the most suitable sample preparation technique for their particular type of HA or FA matrices. This will enhance data comparability among different studies and environmental systems and ultimately allow us to better understand the complex composition of environmental matrices.

Effect of the interaction of fulvic acid with Pb(II) on the distribution of Pb(II) between solid and liquid phases of four minerals

Lead (Pb) is one of the top metal pollutants worldwide, and its distribution between liquid and solid phases of soils is strongly controlled by its adsorption on minerals, organic matter, and their composites. This paper presented the effect of fulvic acid (FA) coexistence on the distribution of Pb(II) at the solid-liquid interface of four minerals, which provided reference for how to use humic substances to remove toxic Pb(II) in soils. The free Pb²⁺ of suspensions, measured by Pb ion selective electrode, was used to characterize the complexation of FA with Pb²⁺ at various pH. The adsorption isotherms of Pb(II) by montmorillonite, kaolinite, goethite, and gibbsite with and without FA were studied with batch experiments. Results indicated that the free Pb²⁺ decreased and complexed Pb(II) increased with the increase of FA concentration in Pb(II)-FA solutions, whether the initial concentration of Pb(II) was 0.1 or 1 mM. Pb²⁺ hydrolysis was low and the free Pb²⁺ concentration in pure lead solution without FA was generally unchanged with increasing solution pH at pH < 6.0. But free Pb²⁺ decreased with the increase of pH in the presence of FA, suggesting that the complexation ability of FA with Pb²⁺ increased with the increase of solution pH. The adsorption of Pb(II) by the minerals without FA followed the order: montmorillonite > kaolinite ≈ goethite > gibbsite at pH5.0. The Pb(II) adsorption by montmorillonite and kaolinite significantly enhanced with 1 g/L FA, while significantly inhibited with 3 g/L FA at low initial Pb(II) concentration. However, the effect of FA on Pb(II) adsorption by montmorillonite was greater than that of kaolinite, which was mainly related to the crystal layer structure, adsorption area, and cation exchange capacity of the minerals. The Pb(II) adsorption by goethite and gibbsite was significantly enhanced by the addition of both 1 g/L and 3 g/L FA, and the enhancement was more evident in goethite system. The effect of FA on the distribution of Pb(II) between solid and liquid phases of the minerals was determined by the factors such as the initial concentration ratio of FA to Pb(II), the adsorption capacity of minerals for FA, and the number of soluble complexes of FA with Pb²⁺. Therefore, the distribution of FA between solid and liquid of four minerals affected the distribution of Pb(II) between solid and liquid phases of the minerals greatly. The results can provide an important reference for understanding the distribution of Pb(II) and the dynamics and mobility of active components in polluted soils.

Effects of fulvic acid and humic acid from different sources on Hg methylation in soil and accumulation in rice

Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury (Hg) in paddy fields are still unclear. Here, fulvic acid (FA) and humic acid (HA) extracted from composted straw (CS), composted cow dung (CCD), peat soil (PM) and lignite coal (LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters (e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of MeHg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg (IHg) by 52.65% and 66.06% and of MeHg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of MeHg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.

Effect of fulvic acid concentration levels on the cleavage of piperazinyl and defluorination of ciprofloxacin photodegradation in ice

Ice is an important physical and chemical sink for various pollutants in cold regions. The photodegradation of emerging fluoroquinolone (FQ) antibiotic contaminants with dissolved organic matter (DOM) in ice remains poorly understood. Here, the photodegradation of ciprofloxacin (CIP) and fulvic acid (FA) in different proportions as representative FQ and DOM in ice were investigated. Results suggested that the photodegradation rate constant of CIP in ice was 1.9 times higher than that in water. When C_FA/C_CIP ≤ 60, promotion was caused by FA sensitization. FA increased the formation rate of cleavage in the piperazine ring and defluorination products. When 60 < C_FA/C_CIP < 650, the effect of FA on CIP changed from promoting to inhibiting. When 650 ≤ C_FA/C_CIP ≤ 2600, inhibition was caused by both quenching effects of 143.9%-51.3% and light screening effects of 0%-48.7%. FA inhibited cleavage in the piperazine ring for CIP by the scavenging reaction intermediate of aniline radical cation in ice. When C_FA/C_CIP > 2600, the light screening effect was greater than the quenching effect. This work provides new insights into how DOM affects the FQ photodegradation with different concentration proportions, which is beneficial for understanding the environmental behaviors of fluorinated pharmaceuticals in cold regions.

Synergistic Cytotoxic and Antimigratory Effect of Brazilein and Doxorubicin on HER2-Overexpressing Cells

OBJECTIVE

The present research aims to report cytotoxic and antimigratory activities of the oxidized form of brazilin, i.e., brazilein, and the effects of the combination of brazilein-doxorubicin on MCF-7/HER2 cells.

METHODS

The MTT assay was conducted to test the cytotoxic activity, while flow cytometry with PI and PI-annexin V staining were respectively performed for cell cycle and apoptosis analyses. Migration and invasion analyses were assessed via Boyden chamber assay, while HER2, Rac1, p120, MMP2, and MMP9 protein levels were determined by immunoblotting and gelatin zymography. Molecular docking of ligands with HER2, Src, PI3Kα, PI3KΔ, and PI3Kγ proteins was evaluated using MOE 2010.

RESULTS

The MTT assay showed that the IC50 value of brazilein against MCF-7/HER2 cells was 51 ± 2.1 µM. Moreover, brazilein and its combination with doxorubicin-induced G2/M accumulation and apoptosis. Combination of brazilein-doxorubicin inhibited cell migration and tended to decrease HER2, Rac1, p120, MMP2, and MMP9 protein expression levels. Based on our molecular docking study, the docking score of brazilein with PI3Kγ is comparable to that of the native ligand.

CONCLUSION

Taken together, a combination of brazilein-doxorubicin exhibited synergistic cytotoxic and antimigratory effects on MCF-7/HER2 cells.<br />.

Effects of environmental factor fulvic acid on AgNPs food chain delivery and bioavailability

Due to its antimicrobial activity, silver nanoparticles (AgNPs) have become the most commonly applied nanomaterials. However, the potential ecotoxicological toxicity of AgNPs in the environment is still unclear. Here we assessed the trophic transfer and toxicity of commercially manufactured polyvinyl pyrrolidone (PVP)-coated AgNPs using a model food chain from Escherichia coli (E. coli) to Caenorhabditis elegans (C. elegans). Our results demonstrated that AgNPs could be accumulated in E. coli and transferred to C. elegans that preyed on the bacteria. Although low concentration of AgNPs had no significant inhibition on E. coli, they could affect germ cell apoptosis, reproduction ability and population size of C. elegans through food chain. Importantly, natural organic matter (NOM), which is omnipresent in environmental system, could increase the accumulation of AgNPs in E. coli and C. elegans, and significantly enhance the ecotoxicity of AgNPs. Our findings indicated that potential risks of nanomaterial through food chain should be considered for higher trophic organisms. And environmental factors could play an important role in transport of nanomaterials and altering their accumulation and toxicity in ecosystem.

Novel selenium-containing photosensitizers for near-infrared fluorescence imaging-guided photodynamic therapy

Benzopyran nitrile dyes cannot be used as qualified photosensitizers due to the low quantum yield of triplet state. The benzopyran derivatives containing selenium instead of oxygen atom based on the heavy atom effect are expected to become potential agents for photodynamic therapy. In this paper, a series of selenium-containing photosensitizers (PS_X) were prepared according to this strategy. PS_X can effectively produce both singlet oxygen and superoxide anions upon laser irradiation. PS_X exhibited the emission wavelength at 500-800 nm and near-infrared (NIR) fluorescence imaging in HeLa cells. Excellent biocompatibility and phototoxicity further indicated that PS_X could be used as efficient photosensitizers for NIR fluorescence imaging and photodynamic therapy.

Identifying the anti-metastasis effect of Anhydroicaritin on breast cancer: Coupling network pharmacology with experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedium brevicornu Maxim. and Cullen corylifolium (L.) Medik. are part of a traditional Chinese medicine (TCM) drug pair (ECDP) widely used in the clinical treatment of breast cancer (BC). Both drugs have been proven to have anti-tumor effect. However, the active ingredients and molecular mechanism of ECDP remain to be explored.

AIM OF THE STUDY

To explore the efficacy and potential mechanisms of actions of herb pair through network pharmacology and in vitro and in vivo experiments.

MATERIALS AND METHODS

The active ingredients of ECDP were identified using high-performance liquid chromatography. The corresponding potential target genes for ECDP components and BC were extracted from established databases, and the protein-protein interaction network of shared genes was constructed using STRING database. The effective ingredients and targets of ECDP for BC were obtained through the TCMSP database and GeneCards database. The potential targets and pathways were selected through the protein interaction network and enrichment analysis. Proliferation and migration experiments in vitro and tumor growth in vivo were performed to evaluate the effects of Anhydroicaritin (AHI) on BC.

RESULTS

AHI is the potential candidate active ingredient of ECDP through TCMSP. Molecular docking revealed that AHI has excellent binding ability with TP53, VEGFA, MMP2, and Met. In vitro experiment results showed that AHI inhibits the growth of MDA-MB-231, 4T1, MCF-7, and SK-BR-3 BC cells. The inhibitory effect of AHI on triple-negative BC cells is more obvious. With the increase of AHI concentration, the colony-forming, migration, and metastasis abilities of the MDA-MB-231 and 4T1 cells gradually decreases. In addition, Western blot and reverse transcription polymerase chain reaction analyses results indicated that AHI downregulates HIF-1α/VEGFA signaling in triple-negative BC cells. AHI inhibits tumor growth and lung metastasis while downregulating the expression of HIF-1α and VEGFA.

CONCLUSION

AHI may play an anti-BC effect by inhibiting cancer cell proliferation, invasion, and metastasis. The results of this study may provide a theoretical basis for AHI research and the clinical application of ECDP in BC.

Controlled-release urea combined with fulvic acid enhanced carbon/nitrogen metabolic processes and maize growth

BACKGROUND

Controlled-release urea (CRU) or fulvic acid (FA), when applied, have been shown to increase nitrogen (N) use efficiency (NUE) or to stimulate plant growth, yet their interactive effects are not well explored. The objective of this study was to investigate the synergistic mechanisms of CRU combined with FA (CRU + FA) on maize (Zea mays L.) growth. Through the experimental design with five treatments, the N metabolism through the transcriptomic analysis of maize leaf, endogenous hormones, photosynthesis enzymes in maize leaf and root, and maize yield and NUE were evaluated.

RESULTS

Compared with CRU treatment, CRU + FA treatment significantly increased auxin, nitrate reductase, and glutamate dehydrogenase in leaf by 35.4%, 43.9%, 40.8% and 19.5%, respectively, as well as, the relative content of the leaf chlorophyll and photosynthetic rate by 14.8% and 45.6%, respectively, at 12-leaf collar stage; the carbon/nitrogen (C/N) metabolic process was significantly enriched in CRU + FA treatment by 312 and 418 genes, according to transcriptome profiles of C/N metabolic in leaves from various fertilizer treated maize; maize yield and NUE of CRU + FA treatment were increased by 6.3% and 38.4%, respectively.

CONCLUSIONS

These results demonstrated that CRU + FA is a viable fertilization scheme that can enhance maize growth, yield and NUE through their synergies in improving N uptake, promoting photosynthesis, increasing C/N metabolic processes, and enhancing enzyme activities. © 2021 Society of Chemical Industry.