Sediment quality classification in freshwater lakes predicted by the history of treatment with copper-based aquatic algaecides.

Copper-based aquatic algaecides have been widely used in the management of aquatic macrophyte and harmful algal blooms for decades due to their effectiveness and low cost. However, repeated treatment of freshwater lakes results in the accumulation of copper in the sediment, which may adversely affect the ecosystem of the lakes through toxicity to benthic invertebrates and other organisms. Consequently, copper-based aquatic herbicides and algaecides have been frequently subjected to regulations aimed at preventing further ecological deterioration in treated waterbodies. Many states in the US are taking or considering taking an approach that limits or prohibits copper treatment in waterbodies. Freshwater lakes with extensive historical copper treatments typically have significantly higher concentrations of copper in the sediment than untreated lakes. However, the correlation between the extent of the treatments and level of copper accumulation in the sediment has not been quantitatively characterized. In the present study, between 2006 and 2017, copper concentrations were measured in the sediment from selected lakes in New York State with different histories of copper-based aquatic algaecide treatment. Analysis of these data confirmed findings from earlier studies conducted by New York State that lakes with histories of copper treatment have significantly higher copper concentrations in the sediment. It also demonstrated that sediment copper concentrations were significantly higher in the sublittoral zone than the littoral zone in treated lakes. Moreover, a positive correlation was detected between sediment copper concentrations and the total number of treatments with copper-based aquatic algaecide for both littoral and sublittoral zones (p-value = 7.94 × 10-8 and 3.1 × 10-13 , respectively). This relationship can be used as a screening tool for regulatory agencies to identify lakes with sediment copper levels possibly higher than the toxicity threshold for aquatic life. Consequently, additional ecological risk assessment may be required before allowing future treatment with copper-based aquatic algaecides. Integr Environ Assess Manag 2024;00:1-12. © 2024 SETAC.

Potential of Copper and Copper Compounds for Anticancer Applications.

Inducing cancer cell death has always been a research hotspot in life sciences. With the continuous deepening and diversification of related research, the potential value of metal elements in inducing cell death has been explored. Taking iron as an example, ferroptosis, mainly characterized by increasing iron load and driving the production of large amounts of lipid peroxides and eventually leading to cell death, has recently attracted great interest in the cancer research community. After iron, copper, a trace element, has received extensive attention in cell death, especially in inducing tumor cell death. Copper and its complexes can induce autophagy or apoptosis in tumor cells through a variety of different mechanisms of action (activation of stress pathways, arrest of cell cycle, inhibition of angiogenesis, cuproptosis, and paraptosis), which are promising in cancer therapy and have become new hotspots in cancer treatment research. This article reviews the main mechanisms and potential applications of novel copper and copper compound-induced cell death, focusing on copper compounds and their anticancer applications.

Copper-Based Compounds against Erwinia amylovora: Response Parameter Analysis and Suppression of Fire Blight in Apple.

Fire blight, caused by Erwinia amylovora, is one of the major bacterial disease of apple and pear, causing enormous economic losses worldwide. Several control measures against E. amylovora have been reported till date, however, none of them have proved to be effective significantly against the pathogen. In this study, mechanisms of the copper-based control agents (CBCAs): copper oxychloride (COCHL), copper oxide (COX), copper hydroxide (CHY), copper sulfate basic (CSB), and tribasic copper sulfate (TCS) and their disease severity reduction efficacy against E. amylovora were analyzed. Bis-1,3-dibutylbarbituric acid trimethine oxonol, carboxyl fluorescein diacetate succinimidyl ester, and 5-cyano-2,3-ditolyl tetrazolium chloride staining were used to check the damage of membrane potential, cytoplasmic pHin, and respiration of CBCAs-treated E. amylovora, respectively. High disturbance in the membrane potential of E. amylovora was found under COX and COCHL treatments. Similarly, higher significant changes in the inner cytoplasmic pHin were observed under COX, COCHL, and TCS treatment. CHY and COCHL-treated E. amylovora showed a significant reduction in respiration. In vitro bioassay results revealed that CHY, CSB, and TCS at 2,000 ppm reduced the severity of fire blight both in pre- and post-treatment of CBCAs in immature apple fruits and seedlings. Overall, the most effective CBCAs against E. amylovora could be CHY at 2,000 ppm as its showed inhibition mechanisms and disease severity reduction.

Toward a harmonized methodology to analyze field side effects of two pesticide products on earthworms at the EU level.

Before plant protection product (PPP) marketing authorization, a risk assessment for nontarget soil organisms (e.g., earthworms) is required as part of Regulation (EC) No. 1107/2009. Following a stepwise approach, higher tier earthworm field studies are needed if they cannot demonstrate low long-term risk based on laboratory studies. The European guidance for terrestrial ecotoxicology refers to ISO guideline 11268-3 as a standard to conduct earthworm field studies. Assessment of such studies may be challenging, as no European harmonized guidance is available to properly analyze the accuracy, representativeness, and appropriateness of experimental designs, as well as the statistical analysis robustness of results and their scientific reliability. Following the ISO guideline 11268-3, a field study was performed in 2016-2017 (Versailles, France). An assessment of the first year of this field study was performed in agreement with the quality criteria provided in 2006 in the guidance document published by de Jong and collaborators and recommendations by Kula and collaborators that allows describing the protocol and results of earthworm field studies. Not only did we underline the importance of a detailed analysis of raw data on the effects of pesticides on earthworms in field situations, but we also provided recommendations to harmonize protocols for assessing higher tier field studies devoted to earthworms to advance a better assessment of PPP fate and ecotoxicity. In particular, we provided practical field observations related to the study design, pesticide applications, and earthworm sampling. Concurrently, in addition to the conventional earthworm community study, we propose carrying out an assessment of soil function (i.e., organic matter decomposition, soil structuration, etc.) and calculating diversity indices to obtain information about earthworm community dynamics after the application of PPPs. Finally, through field observations, any relevant observation of external and/or internal recovery should be reported. Integr Environ Assess Manag 2023;19:254-271. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Modification of the existing maximum residue levels for copper compounds in other small fruits and berries.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Spiess-Urania Chemicals GmbH submitted a request to the competent national authority in Austria to modify the existing maximum residue levels (MRLs) for the active substance copper compounds in the whole group of other small fruits and berries. The data submitted in support of the request were found to be sufficient to derive MRL proposals for the whole subgroup of other small fruits and berries. Adequate analytical methods for enforcement of mineral copper independently from its chemical form are available for matrices under consideration at the validated limit of quantification (LOQ) of 5 mg/kg. Based on indicative risk assessment results, EFSA concluded that the long-term intake of copper residues resulting from the intended and existing uses, natural background levels and monitoring levels might present a risk to consumer health. Although residues in other small fruits and berries are minor contributors to the overall consumer exposure, a risk management decision has to be taken on whether it is appropriate to increase the existing MRLs for these crops, given that a potential consumer intake concern could not be excluded.

Interference of phosphane copper (I) complexes of ß-carboline with quorum sensing regulated virulence functions and biofilm in foodborne pathogenic bacteria: A first report.

Foodborne pathogens are one of the major cause of food-related diseases and food poisoning. Bacterial biofilms and quorum sensing (QS) mechanism of cell-cell communication have also been found to be associated with several outbreaks of foodborne diseases and are great threat to food safety. Therefore, In the present study, we investigated the activity of three tetrahedrally coordinated copper(I) complexes against quorum sensing and biofilms of foodborne bacteria. All the three complexes demonstrated similar antimicrobial properties against the selected pathogens. Concentration below the MIC i.e. at sub-MICs all the three complexes interfered significantly with the quorum sensing regulated functions in C. violaceum (violacein), P. aeruginosa (elastase, pyocyanin and alginate production) and S. marcescens (prodigiosin). The complexes demonstrated potent broad-spectrum biofilm inhibition in Pseudomonas aeruginosa, E. coli, Chromobacterium violaceum, Serratia marcescens, Klebsiella pneumoniae and Listeria monocytogenes. Biofilm inhibition was visualized using SEM and CLSM images. Action of the copper(I) complexes on two key QS regulated functions contributing to biofilm formation i.e. EPS production and swarming motility was also studied and statistically significant reduction was recorded. These results could form the basis for development of safe anti-QS and anti-biofilm agents that can be utilized in the food industry as well as healthcare sector to prevent food-associated diseases.

Peer review of the pesticide risk assessment of the active substance copper compounds copper(I), copper(II) variants namely copper hydroxide, copper oxychloride, tribasic copper sulfate, copper(I) oxide, Bordeaux mixture.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, France, and co-rapporteur Member State, Germany, for the pesticide active substance copper compounds are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of copper compounds as a fungicide on grapes, tomatoes and cucurbits. The reliable end points appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Review of the existing maximum residue levels for copper compounds according to Article 12 of Regulation (EC) No 396/2005.

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance copper compounds. To assess the occurrence of copper compounds residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC and under Regulation (EC) No 1107/2009 as well as the European authorisations reported by Member States (including the supporting residues data). Considering the fact that copper is an element also naturally present in the environment, any data regarding the inherent content of copper in plant and livestock were also considered. Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Some information required by the regulatory framework was missing and a possible chronic risk to consumers was identified. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers. Measures for reduction of the consumer exposure may also be considered.

Synergistic effects between a copper-based metal Casiopeína III-ia and cisplatin.

Additive, subadditive or superadditive interactions observed in combination therapy play an important role in several treatments, particularly for cancer. The isobolographic analysis allows to establish the pharmacological interactions that exist between two drugs that are administered together in equieffective doses. In order to identify if the combination of two compounds presents synergistic interaction, the antiproliferative activity of CasIII-ia with analogue compounds or cisplatin in different molar ratios was evaluated. Results showed that this compound exhibited additive, subadditive or antagonic and superadditive or synergistic interactions, depending on the compound that accompanies it and the proportion of the compounds in the combination. One of the combinations increased the antiproliferative activity from 50 to 77% when the cells were exposed to 4.59 and 9.70 µM to CasIII-ia and cisplatin, respectively. Further studies of the toxicity and biochemical level of the interactions still remain to be studied on a in-vivo xenographed model.

Structure and Magnetic Property Control of Copper Hydroxide Acetate by Non-Classical Crystallization.

Copper hydroxide acetate (CHA), one layered hydroxide compound with tunable magnetism, attracts great interest because of its potential applications in memory devices. However, ferromagnetism for CHA is only demonstrated by means of GPa pressure. Herein, a new method is reported, involving the combination of different crystallization pathways to control crystallization of amorphous CHA toward the formation of CHA/polymer composites with tunable magnetic properties and even a tunability that can be tested at room temperature. By using poly[(ethylene glycol)6 methyl ether methacrylate]-block-poly[2-(acetoacetoxy) ethyl methacrylate] (PEGMA-b-PAEMA) diblock copolymers as additives in combination with a post-treatment process by ultracentrifugation, it is demonstrated that CHA and PEGMA-b-PAEMA form composites exhibiting different magnetic properties, depending on CHA in-plane nanostructures. Analytical characterization reveals that crystallization of CHA is induced by ultracentrifugation, during which CHA nanostructures can be well controlled by changing the degrees of polymerization of the PEGMA and PAEMA blocks and their block length ratios. These findings not only present the first example of using crystallization from polymer stabilized amorphous precursors toward the generation of magnetic nanomaterials with tunable magnetism but also pave the way for the future design of functional composite materials.

A heterobimetallic copper-titanium oxo cluster with a new structural motif.

ABSTRACT: Mixed-metal oxo clusters Cu4Ti5O6(OOCR)16 (OOCR = methacrylate, propionate) were obtained by reaction of titanium alkoxides and copper carboxylates with propionic or methacrylic acid.

Correlation between DNA interactions and cytotoxic activity of four new ternary compounds of copper(II) with N-donor heterocyclic ligands.

Four new ternary complexes of copper(II) were synthesized and characterized: [Cu(hyd)(bpy)(acn)(ClO4)](ClO4)] (1), [Cu(hyd)(phen)(acn)(ClO4)](ClO4)] (2), [Cu(Shyd)(bpy)(acn)(ClO4)](ClO4)] (3) and [Cu(Shyd)(phen)(acn)(ClO4)](ClO4)] (4), in which acn=acetonitrile; hyd=2-furoic acid hydrazide, bpy=2,2-bipyridine; phen=1,10-phenanthroline and Shyd=2-thiophenecarboxylic acid hydrazide. The cytotoxic activity of the complexes in a chronic myelogenous leukemia cell line was investigated. All complexes are able to enter cells and inhibit cellular growth in a concentration-dependent manner, with an activity higher than that of the corresponding free ligands. The substitution of Shyd for hyd increases the activity, while the substitution of bpy for phen renders the complex less active. Therefore, the most potent complex is 4 with an IC50 value of 1.5±0.2µM. The intracellular copper concentration needed to inhibit 50% of cell growth is approximately 7×10(-15)mol/cell. It is worth notifying that a correlation between cytotoxic activity, DNA binding affinity and DNA cleavage was found: 1<3<2<4.

Bis[4-amino-N-(pyrimidin-2-yl)benzenesulfonamido]diamminecopper(II): aqua or ammine ligands?

Diffraction results obtained at 100 and 291 K, the former at high resolution, are reported for the title compound, [Cu(C10H9N4O2S)2(NH3)2] or [Cu(sulfa)2(NH3)2] [Hsulfa is 4-amino-N-(pyrimidin-2-yl)benzenesulfonamide]. The Cu(II) cation is coordinated by two N-atom donors from a bidentate sulfa ligand, by two ammonia molecules in the equatorial plane and by a monohapto (η(1)) sulfadiazine at the apex of a distorted square pyramid. The present interpretation and two earlier reports [Brown, Cook & Sengier (1987). Acta Cryst. C43, 2332-2334; Tommasino, Renaud, Luneau & Pilet (2011). Polyhedron, 30, 1663-1670] disagree about the nature and geometry of the ligands. The relationship between the present result and the former is discussed, and evidence is provided that the latter erroneously assigned an ammine as an aqua ligand.