Chlorophenol stress affects aromatic amino acid biosynthesis-a genome-wide study

Phenolic compounds in water: Review of occurrence, risk, and retention by membrane technology

Phenolic compounds are one of the main contributors to water source contamination worldwide. In this review, the data collected on Elsevier, Scopus, and Pubmed, considering papers published between 2000 and 2023, showed more than 60 different phenols have been identified in water matrix (<0.065-179,000,000 ng L-1). The highest concentration reported was in surface water canals in India. The most recurrent and studied compound was bisphenol A (n = 93) in concentrations ranging from 0.45 to 2,970,000 ng L-1. The solid phase extraction (HBL Oasis cartridge) and methanol as solvent was the method of pre-concentration most used followed by gas chromatography for the determination of phenols in water samples. The importance of drinking water guidelines incorporating more phenolic compounds was emphasized given the variety of these compounds quantified in water matrix. The human health risk assessment (HRA) was performed for the min-max concentrations of the pollutants reported in the literature. High HRA even at the lowest concentrations for 2-nitrophenol, 2,6-dichlorophenol, 3,4,5-trichlorophenol, 2,3,4,6-tetrachlorophenol, and 2,4-dinitrophenol was recognized. The cancer risk estimated was considered possible for 3-methylphenol, 2,4-dimethylphenol, 2,4,6-trichlorophenol, pentachlorophenol, and 2,4-dinitrophenol in the highest concentrations. The in-depth discussion of mechanisms, advantages, challenges, and carbon footprint of membrane technologies in water treatment and phenols retention demonstrated the great potential and trends for the production of safe drinking water, highlighting reverse osmosis, as a mature technology, and membrane distillation, as an emergent technology.

Validation of the Pathogenic Effect of IGHMBP2 Gene Mutations Based on Yeast S. cerevisiae Model

Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a heritable neurodegenerative disease characterized by rapid respiratory failure within the first months of life and progressive muscle weakness and wasting. Although the causative gene, IGHMBP2, is well defined, information on IGHMBP2 mutations is not always sufficient to diagnose particular patients, as the gene is highly polymorphic and the pathogenicity of many gene variants is unknown. In this study, we generated a simple yeast model to establish the significance of IGHMBP2 variants for disease development, especially those that are missense mutations. We have shown that cDNA of the human gene encodes protein which is functional in yeast cells and different pathogenic mutations affect this functionality. Furthermore, there is a correlation between the phenotype estimated in in vitro studies and our results, indicating that our model may be used to quickly and simply distinguish between pathogenic and non-pathogenic mutations identified in IGHMBP2 in patients.

Enhanced Bioremediation of 4-Chlorophenol by Electrically Neutral Reactive Species Generated from Nonthermal Atmospheric-Pressure Plasma

4-Chlorophenol (4-CP) is a chlorinated aromatic compound with broad industrial applications. It is released into the environment as an industrial byproduct and is highly resistant to biodegradation. Pseudomonas sp. in the environment and activated sludge are used for 4-CP bioremediation; however, the degradation of 4-CP takes a long time. Consequently, the toxicity of 4-CP is a major barrier to its bioremediation. In this study, we investigated the synergistic effect of electrically neutral reactive species on the bacterial bioremediation of 4-CP. Our results showed that the concentration of 4-CP decreased from 2.0 to 0.137 mM and that it was converted to 4-chlorocatechol (4-CC; 0.257 mM), 4-chlororesorcinol (0.157 mM), hydroquinone (0.155 mM), and trihydroxy chlorobenzene and their respective ring-cleaved products following irradiation of neutral reactive species. These compounds were less toxic than 4-CP, except for 4-CC, which reduced the toxicity of 4-CP to Pseudomonas putida. When the neutral reactive species-treated 4-CP fraction was added to P. putida cultured in a synthetic sewage medium for 48 h, the 4-CP concentration was reduced to 0.017 mM, whereas nontreated 4-CP (2.0 mM) was hardly degraded by P. putida. These results suggest that the biodegradation of 4-CP can be efficiently improved by combining irradiation of neutral reactive species with microbial treatment. The irradiation of neutral reactive species of environmental pollutants may additionally lead to further improvements in bioremediation processes.

Studies on the degradation of trace phenol and indole odorants by chlorine and permanganate in drinking water treatment

The frequent detection of phenols and indoles in source water gives rise to concern about the taste and odor problems mainly caused by some chemicals. Exploration for the efficient removal of trace amounts of phenols and indoles in source water is imperative. This study investigated the removals and oxidation kinetics of 3-methylphenol (3-MP), 2,6-dichlorophenol (2,6-DCP), indole and 3-methylindole (3-MI) by NaClO and KMnO₄. The results showed that the selected chemical odorants could be removed by NaClO and KMnO₄. Meanwhile, the oxidation processes could be well described by the second-order kinetics model, in which kinetics constants of chemical odorants were from 1.44 × 10⁴ to 1.45 × 10⁶ L·mol^-1·min^-1 and followed the order 3-MI > indole> 3-MP> 2,6-DCP by NaClO. However, the kinetics constants for the selected chemical odorants were also determined from 1.10 × 10³ to 2.25 × 10⁴ L·mol^-1·min^-1 and in the order 2,6-DCP> 3-MI> 3-MP > indole by KMnO₄. The phenols degradation mechanisms by NaClO are chlorine substitution, and the products generated are 3,4,6-trichloro-2-methylphenol, 2,4,6-trichlorophenol, etc. And that of indoles are chlorine substitution and hydroxylation by NaClO, which generated 6-chloroindole, 2,6-dichloroaniline, etc. The phenols degradation pathways are oxidative coupling reactions by KMnO₄, and that of indoles are hydroxylation reactions by KMnO₄. This study provides a further basis for NaClO and KMnO₄ oxidation to remove trace phenols and indoles in drinking water pre-treatments.

Review on the hazardous applications and photodegradation mechanisms of chlorophenols over different photocatalysts

Chlorophenols are very important environmental pollutants, which have created huge problems for both aquatic and terrestrial lives. Therefore, their removal needs urgent, effective, and advanced technologies to safeguard our environment for future generation. This review encompasses a comprehensive study of the applications of chlorophenols, their hazardous effects and photocatalytic degradation under light illumination. The effect of various factors such as pH and presence of different anions on the photocatalytic oxidation of chlorophenols have been elaborated comprehensively. The production of different oxidizing agents taking part in the photodegradation of chlorophenols are given a bird eye view. The photocatalytic degradation mechanism of different chlorophenols over various photocatalyts has been discussed in more detail and elaborated that how different photocatalysts degrade the same chlorophenols with the aid of different oxidizing agents produced during photocatalysis. Finally, a future perspective has been given to deal with the effective removal of these hazardous pollutants from the environment.

Influence of tetraconazole on the proteome profile of Saccharomyces cerevisiae Lalvin T73™ strain

This work aimed to evaluate the modifications on the proteome profile of Saccharomyces cerevisiae T73™ strain as a consequence of its adaptive response to the presence of tetraconazole molecules in the fermentation medium. Pasteurised grape juices were separately supplemented with tetraconazole or a commercial formulation containing 12.5% w/v of tetraconazole at two concentration levels. In addition, experiments without fungicides were developed for comparative purposes. Proteome profiles of yeasts cultured in the presence or absence of fungicide molecules were different. Independently of the fungicide treatment applied, the highest variations concerning the control sample were observed for those proteins involved in metabolic processes, especially in the metabolism of nitrogen compounds. Tetraconazole molecules altered the abundance of several enzymes involved in the biosynthesis of amino acids, purines, and ergosterol. Moreover, differences in the abundance of several enzymes of the TCA cycle were found. Changes observed were different between the active substance and the commercial formulation. SIGNIFICANCE: The presence of fungicide residues in grape juice has direct implications on the development of the aromatic profile of the wine. These alterations could be related to changes in the secondary metabolism of yeasts. However, the molecular mechanisms involved in the response of yeasts to fungicide residues remains quite unexplored. Through this exhaustive proteomic study, alterations in the amino acids biosynthesis pathways due to the presence of the tetraconazole molecules were observed. Amino acids are precursors of some important higher alcohols and ethyl acetates (such as methionol, 2-phenylethanol, isoamyl alcohol or 2-phenylacetate). Besides, the effect of tetraconazole on the ergosterol biosynthesis pathway could be related to a higher production of medium-chain fatty acids and their corresponding ethyl acetates.

2,4-Dichlorophenol induces DNA damage through ROS accumulation and GSH depletion in goldfish Carassius auratus

2,4-Dichlorophenol (2,4-DCP) is one of the most abundant chlorophenols in the aquatic environment and has been frequently detected in surface waters. Although ecological and cellular toxicity of 2,4-DCP has aroused the public concern, few reports focus on the genotoxicity, especially on DNA double strand breaks (DSBs), of 2,4-DCP in fish. The present study aims to explore the genotoxic effect of 2,4-DCP on DSBs in goldfish Carassius auratus and to further elucidate its potential mechanism. The results showed that 2,4-DCP significantly induced DSBs (detected by neutral comet assay) in erythrocytes and hepatocytes of goldfish in a dose-dependent manner, indicating a genotoxicity of 2,4-DCP on fish. The total antioxidant capability and the content of reduced glutathione (GSH) were significantly decreased, while the level of reactive oxygen species (ROS) was significantly increased in a dose-dependent manner in erythrocytes and hepatocytes, suggesting an oxidative stress caused by 2,4-DCP in fish. N-acetyl-l-cysteine, a precursor of GSH and a ROS scavenger, significantly impaired 2,4-DCP-induced ROS overproduction and DSBs, which proves that ROS accumulation and GSH depletion are involved in 2,4-DCP-induced DNA damage in fish. Environ. Mol. Mutagen. 59:798-9, 2018. © 2018 Wiley Periodicals, Inc.

Endoplasmic reticulum stress is involved in 2,4-dichlorophenol-induced hepatotoxicity

2,4-Dichlorophenol (2,4-DCP) is an environmental pollutant exhibiting a wide spectrum of toxic effects. We investigated the toxic effects and potential mechanisms underlying 2,4-DCP-induced hepatotoxicity. In vitro, 2,4-DCP caused hepatotoxicity manifested by a decrease in cell viability and inhibition of colony formation. Bip and CHOP expression was up-regulated at the mRNA and protein levels. Moreover, 2,4-DCP induced eIF2α phosphorylation and Xbp1 mRNA splicing, indicating that endoplasmic reticulum (ER) stress was activated after exposure of HL7702 cells to 2,4-DCP for 12 hr. Furthermore, the mitochondrial membrane potential collapsed and apoptosis was triggered after exposure to 2,4-DCP for 24 hr. In vivo, 2,4-DCP caused histological changes in the liver, and dramatically elevated the serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels of mice. ER stress was also triggered in the liver of mice on days 1 and 3. The ER stress inhibitor TUDCA could partly relieve the liver damage, as indicated by the restoration of serum ALT and AST levels. Taken together, our results demonstrated that ER stress may serve as an early warning mechanism against 2,4-DCP-induced hepatotoxicity, and severe ER stress may lead to apoptosis.

2,4-dichlorophenol induces ER stress-mediated apoptosis via eIF2α dephosphorylation in vitro

2,4-Dichlorophenol (2,4-DCP) has been widely used to produce herbicides and pharmaceutical intermediates, which exhibits various toxic effects including apoptosis. However, the mechanisms underlying 2,4-DCP-induced apoptosis, especially mediated by endoplasmic reticulum (ER) stress, are still unknown. In the present study, the mouse embryonic fibroblasts (MEFs) were used as an in vitro model system to figure out whether 2,4-DCP could induce ER stress, and further to elucidate the role of ER stress in 2,4-DCP-induced apoptosis. The results showed that 2,4-DCP dramatically caused the decrease of cell viability, the increase of apoptotic cells, the collapse of mitochondrial membrane potential (MMP) and the activation of caspase-3, suggesting that 2,4-DCP did induce apoptosis. Meanwhile, 2,4-DCP acted similarly as ER stress agonist tunicamycin (Tu) to activate all three branches (IRE1α, ATF6 and eIF2α) of ER stress. Furthermore, repression of ER stress or inhibition of eIF2α dephosphorylation significantly alleviated 2,4-DCP-induced apoptosis. Taking these results together, the present study firstly showed that 2,4-DCP induced ER stress-mediated apoptosis via eIF2α dephosphorylation in mammalian cells. These findings will provide new insights into the mechanisms underlying apoptosis after chlorophenols exposure.

Saccharomyces cerevisiae as a model in ecotoxicological studies: A post-genomics perspective

The budding yeast Saccharomyces cerevisiae represents a well-consolidated and widely used eukaryotic model, with a number of features that make it an ideal organism to carry out functional toxicological studies. Several advantages are permitted by the use of yeast cells, as the possibility to identify molecular biomarkers, unknown mechanisms of action and novel potential targets. Thanks to the evolutionary conservation, yeast can provide also useful clues allowing the prioritization of more complex analyses and toxicity predictions in higher eukaryotes. The last two decades were incredibly fruitful for yeast "omics", but referring to the analysis of the effects of pesticides on yeast much still remains to be done. Furthermore, a deeper knowledge of the effects of environmental pollutants on biotechnological processes associated with the use of yeasts is to be hoped.