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Nowadays, contamination by polycyclic aromatic hydrocarbons (PAHs) has become a serious problem all over the world; in particular, high-molecular-weight PAHs (HWM PAHs, four to seven rings) are more harmful to human health and environment due to their more complex structure and metabolic pathway. Biodegradation of PAHs with six or more rings, such as indeno[1,2,3-cd]pyrene (IcdP), was rarely described. An IcdP-degrading strain, Rhodococcus aetherivorans IcdP1, was isolated from HWM PAH-contaminated soil. It could grow on and efficiently degrade various HWM PAHs, such as IcdP, benzo[a]pyrene, and benzo[j]fluoranthene. It showed highest degrading ability toward IcdP (> 70% within 10 days). The IcdP degradation was initiated by ring hydroxylation with multiple pathways, including the hydroxylation at the 1,2 and 7,8 positions, according to the relevant metabolites detected, e.g., cyclopenta[cd]pyrene-3,4-dicarboxylic acid and 2,3-dimethoxy-2,3-dihydrofluoranthene. The transcriptional patterns of the genes encoding ring-hydroxylating oxygenases (RHOs) and cytochrome P450 monooxygenases (CYP450s) under the induction of IcdP, pyrene, and benzo[b]fluoranthene (BbF) were compared to determine the key initial RHOs in the conversion of IcdP. The expression of genes encoding RHOs 1892–1894, 1917–1920, and 4740–4741 was induced strictly by IcdP, and the amino acid sequences of these proteins showed very low identities with their homologs. These results suggested that IcdP was degraded through a dioxygenation-initiated metabolism pattern, and RHOs 1892–1894, 1917–1920, and 4740–4741 responded to the initial ring cleavage of IcdP through 1,2-dihydrodiol or 7,8-dihydrodiol. The studies would contribute to the understanding of the molecular mechanism of initial degradation of IcdP.

Nowadays, contamination by polycyclic aromatic hydrocarbons (PAHs) has become a serious problem all over the world; in particular, high-molecular-weight PAHs (HWM PAHs, four to seven rings) are more harmful to human health and environment due to their more complex structure and metabolic pathway. Biodegradation of PAHs with six or more rings, such as indeno[1,2,3-cd]pyrene (IcdP), was rarely described. An IcdP-degrading strain, Rhodococcus aetherivorans IcdP1, was isolated from HWM PAH-contaminated soil. It could grow on and efficiently degrade various HWM PAHs, such as IcdP, benzo[a]pyrene, and benzo[j]fluoranthene. It showed highest degrading ability toward IcdP (> 70% within 10 days). The IcdP degradation was initiated by ring hydroxylation with multiple pathways, including the hydroxylation at the 1,2 and 7,8 positions, according to the relevant metabolites detected, e.g., cyclopenta[cd]pyrene-3,4-dicarboxylic acid and 2,3-dimethoxy-2,3-dihydrofluoranthene. The transcriptional patterns of the genes encoding ring-hydroxylating oxygenases (RHOs) and cytochrome P450 monooxygenases (CYP450s) under the induction of IcdP, pyrene, and benzo[b]fluoranthene (BbF) were compared to determine the key initial RHOs in the conversion of IcdP. The expression of genes encoding RHOs 1892–1894, 1917–1920, and 4740–4741 was induced strictly by IcdP, and the amino acid sequences of these proteins showed very low identities with their homologs. These results suggested that IcdP was degraded through a dioxygenation-initiated metabolism pattern, and RHOs 1892–1894, 1917–1920, and 4740–4741 responded to the initial ring cleavage of IcdP through 1,2-dihydrodiol or 7,8-dihydrodiol. The studies would contribute to the understanding of the molecular mechanism of initial degradation of IcdP. [ABSTRACT FROM AUTHOR]

Lesion to the retinal pigment epithelium (RPE) is a crucial event in the development of age-related macular degeneration (AMD), the leading cause of blindness in industrialized countries. Tobacco smoking and high-energy visible blue (HEV; 400-500 nm) light exposure are major environmental risk factors for AMD. Individually, they have been shown to cause damage to the RPE. Tobacco smoke contains toxic polycyclic aromatic hydrocarbons (PAH) that can accumulate in RPE and which absorb HEV light. It can thus be postulated that the interaction between both factors in RPE cells can have a synergic toxic effect to the RPE. To test this hypothesis, cultured human RPE cells (ARPE19) were treated with nanomolar concentrations of benzo[a]pyrene (BaP) or indeno[1,2,3-cd]pyrene (IcdP), then exposed to HEV light using an irradiation system that mimics the solar spectrum normally transmitted to the retina through the human ocular media. Using mitochondrial network morphology changes and key features of AMD-related RPE defects such as apoptotic cell death and oxidative stress, we demonstrate that a synergistic phototoxicity is generated when nanomolar concentrations (≤ 500 nM) of IcdP interact with sub-lethal amounts of HEV light. Indeed, we found IcdP to be at least 3000 times more toxic for RPE cells when irradiated with HEV light. This synergy translates into disruption of mitochondrial network, ROS enhanced accumulation and apoptosis of RPE cells. Our results underline an important interplay between two environmental risk factors involved in AMD progression and strongly indicate that IcdP, upon interaction with HEV light, may initiate the biological mechanisms underlying the association between cigarette smoking and AMD-related RPE degeneration. [ABSTRACT FROM AUTHOR]

Currently, the environmental impact of ubiquitous plastic debris triggered quite some public attention. However, the global impact of microplastic on human health is by and large either unknown or neglected. By looking at the underlying biochemical mechanisms leading to the global health threat microplastic was discovered to carry persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAH), to marine life. The effect of microplastic-ingestion in the human body remains unfortunately somewhat elusive as of yet. For this reason, we screened for compounds binding to the human estrogen receptor α (ERα) and identified the PAH compounds indeno[1,2,3- cd pyrene (Indpy) and picene (Pice) with a high binding affinity. We applied next generation sequencing to analyze the differentially expressed genes in MCF-7 cells after treatment with Indpy and Pice. We found 8 upregulated genes: ABCC5 , CCNG2 , CYP1A1 , DDIT4 , IER3 , RUNX2 , STC2 , and SLC7A5 and 14 downregulated genes: ADORA1 , CEBPB , CELSR2 , CTSD , CXCL12 , KRT19 , PGR , PKIB , RARA , RET , SEMA3B , SIAH2 , TFAP2C , and XBP1 induced by both ligands and associated with ESR1 -regulation. The altered gene expression may influence cell proliferation and metastasis, favoring cancer development with a poor response to therapy. In addition, we confirmed the binding of Indpy and Pice to ERα using molecular docking and microscale thermophoresis. ERα activation was measured with ESR1 -overexpressing HEK293 (HEK-ESR1) cells and confirmed for Indpy. In conclusion, we showed an ESR1 -mediated influence of the PAH compounds Indpy and Pice on the gene expression pattern of MCF-7 cells, possibly also promoting breast cancer development in patients. • Indeno[1,2,3- cd pyrene and Picene interact with the estrogen receptor α. • Both polycyclic aromatic hydrocarbons promote cancer development in MCF-7 cells. • RNA-sequencing reveals differentially expressed genes after treatment with PAHs. [ABSTRACT FROM AUTHOR]

• Modified method for heat capacity determination of powdered samples was tested. • Low-temperature heat capacities for three PAHs were measured. • It was found that obsolete data for Al 2 O 3 and Cu are frequently used. Experimental heat capacities of three polycyclic aromatic hydrocarbons (PAHs), benzo[b]fluoranthene (CAS RN: 205-99-2), benzo[k]fluoranthene (CAS RN: 207-08-9), and indeno[1,2,3-cd]pyrene (CAS RN: 193-39-5) in the temperature range (2–300) K are reported (to our knowledge for the first time). Commercially available relaxation calorimeter was used for measurement. Performance of the apparatus was tested by measuring the heat capacity of copper and sapphire. However, PAHs are available in a form of powder and therefore cannot be directly placed on measuring platform as e.g. copper specimen; moreover, sample sublimation cannot be ruled out. Modified three-step method using powder sample or powder sample pressed into a pellet and inserted into aluminium DSC pans of different weights was tested by measurement of anthracene heat capacity, for which high quality data are available in the literature. Pellets of higher weight in a pan of higher mass yielded results in the best accordance with the literature data; this method was applied also for measurement of benzoic acid heat capacity. Finally, datasets on heat capacity of benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, and indeno[1,2,3- cd ]pyrene were recorded, smoothed and standard thermodynamic functions in the temperature range (0–300) K were calculated; standard entropy in crystalline state at 298.15 K is 270.1 ± 5.4 J·K−1·mol−1 for benzo[b]fluoranthene, 263.5 ± 5.3 J·K−1·mol−1 for benzo[k]fluoranthene, and 272.8 ± 5.4 J·K−1·mol−1 for indeno[1,2,3-cd]pyrene. [ABSTRACT FROM AUTHOR]

Dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) is one of the most interesting sample preparation techniques developed in recent years. Although several applications have been reported, the potentiality and limitations of this simple and rapid extraction technique have not been made sufficiently explicit. In this work, the extraction efficiency of DLLME-SFO for pollutants from different chemical families was determined. Studied compounds include: 10 polycyclic aromatic hydrocarbons, 5 pesticides (chlorophenoxy herbicides and DDT), 8 phenols and 6 sulfonamides, thus, covering a large range of polarity and hydrophobicity (LogKow 0-7, overall). After optimization of extraction conditions using 1-dodecanol as extractant, the procedure was applied for extraction of each family from 10-mL spiked water samples, only adjusting sample pH as required. Absolute recoveries for pollutants with LogKow 3-7 were >70% and recovery values within this group (18 compounds) were independent of structure or hydrophobicity; the precision of recovery was very acceptable (RSD<12%) and linear behavior was observed in the studied concentration range (r(2)>0.995). Extraction recoveries for pollutants with LogKow 1.46-2.8 were in the range 13-62%, directly depending on individual LogKow values; however, good linearity (r(2)>0.993) and precision (RSD<6.5%) were also demonstrated for these polar solutes, despite recovery level. DLLME-SFO with 1-dodecanol completely failed for extraction of compounds with LogKow≤1 (sulfa drugs), other more polar extraction solvents (ionic liquids) should be explored for highly hydrophilic pollutants., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Aqueous concentrations of individual polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in coastal sites of two marine protected areas (MPAs), that is, Asinara and the La Maddalena Archipelago, in Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even in very low concentrations of (pgL(-1)), in seawater. The results reveal significant differences between the two sampling areas relative to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were generally observed at levels below the detection limits of the utilised method., (Copyright © 2013 Elsevier Ltd. All rights reserved.)