Photosynthesis, the basal manufacturing process in the earth is habitually restricted by airborne micropollutants such as phenanthrene (PHE). Here, we show that 24-epibrassinolide (EBR), a bioactive plant steroid is able to keep higher photosynthetic capacity consistently for a long period under a shoot-imposed PHE stress in tomato. EBR-promoted photosynthetic capacity and efficiency eventually resulted in a 37.5% increase of biomass under PHE stress. As primary response, transcripts of antioxidant genes were remarkably induced by EBR in PHE-treated plants. Activities of antioxidant and detoxification enzymes were also enhanced by EBR. Notably, EBR-induced higher antioxidant potential was associated with reduced levels of H2O2 and O2—, resulting in a 32.7% decrease of content of malondialdehyde in the end of experiment and relatively healthy chloroplast ultrastructure in EBR + PHE treatment compared with PHE alone. These results indicate that EBR alleviates shoot-imposed PHE phytotoxicity by maintaining a consistently higher photosynthetic capacity and antioxidant potential in tomato.

During the last few years, the induction of toxicological mechanisms by atmospheric ultrafine particles (UFP) has become one of the most studied topics in toxicology and a subject of huge debates. Fine particles (FP) and UFP collected at urban and rural sites in Lebanon were studied for their chemical composition and toxicological effects. UFP were found more enriched in trace elements, secondary inorganic ions, total carbon and organic compounds than FP. For toxicological analysis, BEAS-2B cells were exposed for 24, 48 and 72 h to increasing concentrations of FP, water-UFP suspension (UFPw) and UFP organic extract (UFPorg). Our findings showed that UFP caused earlier alterations of mitochondrial metabolism and membrane integrity from the lowest concentrations. Moreover, a significant induction of CYP1A1, CYP1B1 and AhRR genes expression was showed after cells exposure to UFPorg and to a lesser extent to UFPw and FP samples.

Endocrine disrupting chemicals, such as the free estrogens 17β-estradiol (E2), estrone (E1) and the conjugated estrogen estrone-sulfate (E1-3S) are found at low concentration levels in the environment. This is somehow contradictory to the strong sorption and high degradation potentials found in laboratory experiments. In particular, the fate and transport behavior of conjugated estrogens is poorly understood, and the importance of enzymes triggering the transformation pathways has received little attention. To address these deficiencies, the present research uses packed laboratory soil columns with pulse injections of free estrogens, either E2 or E1, or E1-3S, to provide sound evidence of the transformation pathways. It is further shown that (i) transport of free estrogens is subject to strong retardation and degradation, (ii) the transport of conjugated estrogens is less retarded and only to a minor degree affected by degradation, and (iii) arylsulfotransferase is the enzyme triggering the transformation reaction.

A multi-biomarker approach, including several lysosomal parameters, activity and mRNA expression of antioxidant enzymes, and DNA damage, was employed to investigate the nominal effects of 0.3 ng/L fluoxetine (FX) and 0.3 ng/L propranolol (PROP) alone or in combination (0.3 ng/L FX + 0.3 ng/L PROP) on Mediterranean mussels after a 7 day treatment. FX co-exposure appears to facilitate PROP bioaccumulation because PROP only accumulated in digestive gland of FX + PROP treated mussels. Lysosomal parameters were significantly impaired by FX + PROP treatment, while no clear antioxidant responses at the catalytic and transcriptional levels were observed. Biomarker responses led to a “medium stress level” diagnosis in FX + PROP treated mussels, according to the Expert System, whereas 0.3 ng/L PROP or FX alone did not induce consistent stress conditions. These findings suggest vulnerability of coastal marine mussels to FX and PROP contamination at environmentally relevant levels.

Biodegradation of diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) by three marine algae was investigated. When they were coexistent, DBP was degraded more quickly than DEP. The first-order biodegradation rate constants of DBP in the algal solutions were in the order of Cylindrotheca closterium (0.0169h−1)>Dunaliella salina (0.0035h−1) and Chaetoceros muelleri (0.0034h−1). When singly existed, DEP was degraded more quickly than in a mixture with DBP, indicating that DBP had inhibitory effect on the biodegradation of DEP. Moreover, the degradation trends of DEP and DBP in both extra- and intracellular crude extracts were similar to those in algal solutions. At the end, DEP was largely in water phase, whereas DBP remained in both water phase and algal phase. It can be concluded that biodegradation of DEP was mainly by algal extracellular enzymes, and both extra- and intracellular enzymes played key roles in the degradation of DBP.

Lettuce plants were exposed to different toxic levels of arsenic (As) to induce an oxidative stress response, and the role of nitric oxide (NO) (provided as sodium nitroprusside (SNP)) as an attenuating agent of this stress condition was evaluated. Plants were treated with 50 μM of As with or without 100 μM SNP added to the nutrient solution. The hydrogen peroxide, superoxide anion, and malondialdehyde concentrations and enzymatic activities were measured. The increase in As concentration detected in the leaves was followed by a significant increase in H₂O₂ and malondialdehyde (MDA) concentrations. However, the presence of SPN promoted a reduction in the concentration of these oxidative agents and also reduced the translocation of As to the shoots. The enzymatic activities in the plants exposed to As were increased, which indicates the active participation of these enzymes in the reduction of oxidative stress induced by the metalloid. In the plants exposed to As and SNP, the enzymatic activities were not so high; this result was possibly related to the direct action of NO in scavenging the generated toxic metabolites and with the reduction in the translocation of the pollutant to the shoots. Lettuce and leaves of other vegetables are usually ingested, and this study shows an alternative to avoid human contamination with As.

The purpose of this review is to describe how plants take up lead and its distribution to plant parts, morphological, physiological, and biological effects of lead on plants, sequestration strategies, and tolerance mechanisms including detoxification. How lead despite its lack of essential function in plants, causes phytotoxicity by changing cell membrane permeability, by reacting with active groups of different enzymes involved in plant metabolism by reacting with the phosphate groups of adenosine diphosphate (ADP) or adenosine-5′-triphosphate (ATP). Moreover, we also address role of hyperaccumulating plants in lead absorption. How synthetic chelators such as ethylenediaminetetraacetic acid (EDTA) enhances the availability of heavy metal lead in soils and increase phytoextraction efficiency in aboveground harvestable plant parts through enhancing the metal solubility and translocation from roots to shoots, metal tolerance, and future prospectives to decrease lead pollution.

Tremendous surge in the industrialization and infrastructure development worldwide have led to a significant rise in environmental pollutants in the last 2–3 decades. Pollutants in the natural environment consist of highly diversified and complex mixtures. A single biomarker cannot be used to assess a complete identification of environmental pollutants. In this context, it is highly recommended by environmental scientists to evaluate a set of complementary biomarkers for the complete assessment of toxic burden of complex environmental pollutants in the exposed organisms. Moreover, a multiple biomarker approach for the stress assessment is believed to have high sensitivity and could be done in comparatively lesser measuring time. The present article focuses on the viability of usage of xenobiotic detoxification enzymes viz. phase I and II as the toxicity biomarkers. As far as our knowledge goes, we are for the first time reporting phase I and phase II enzymes together as potential toxicity biomarkers in a single article.

The mutagenic and genotoxic activity of vinasses collected from a fuel alcohol plant, located in the municipality of Frontino, Northwestern Colombia, were evaluated. Two samples obtained from an 82-L capacity hybrid reactor (UASB-anaerobic filter (AF)-UASB) were studied under laboratory conditions after being treated with biological oxidation, the first, and the second with Fenton reaction consecutively. Mutagenicity was evaluated in vitro by the Ames test using strains TA98 and TA100 with and without S9 metabolic activation. The genotoxic analysis was conducted using the Allium cepa roots assay where chromosomal aberrations were used as clastogenic or aneugenic response markers, and micronuclei as mutagenic response. The Ames test results showed a strain-dependent positive linear association with the vinasse sample concentration before treatment (dose–response effect). Unlike TA100, strain TA98 showed a mutagenic effect in both the presence and absence of metabolic enzymes. After the biological oxidation treatment, vinasse mutagenicity significantly decreased. Finally, after Fenton treatment, the sample did not induce any mutagenic event. Genotoxic activity was observed in all three samples, but there was a higher frequency in the vinasse sample before treatment. Concerning the frequency of micronuclei, no clear association was observed with either the concentration or the type of sample.

The feasibility of using cell-free extracts of nitrifying sludge to treat synthetic wastewater containing 4-methylphenol and ammonium was examined. Nitrifying cells were broken by sonication and encapsulated into calcium alginate. Cell-free extracts (CFE) of nitrifying sludge oxidized 4-methylphenol threefold faster than whole-cells, but CFE were not able to oxidize ammonium. The CFE encapsulated into calcium alginate (CFEA) displayed partial nitrification and 4-methylphenol oxidation. Five hours was enough to oxidize 100 % of ammonium and 4-methylphenol, at volumetric rates of 20.80 mg N/L h and 42.86 mg C/L h, respectively. It is inferred that an interaction between the CFE and calcium alginate resulted in the protection of the enzymes.