We investigated the ability of the aquatic fern Azolla to take up ciprofloxacin (Cipro), as well as the effects of that antibiotic on the N-fixing process in plants grown in medium deprived (-N) or provided (+N) with nitrogen (N). Azolla was seen to accumulate Cipro at concentrations greater than 160 μg g⁻¹ dry weight when cultivated in 3.05 mg Cipro l⁻¹, indicating it as a candidate for Cipro recovery from water. Although Cipro was not seen to interfere with the heterocyst/vegetative cell ratios, the antibiotic promoted changes with carbon and nitrogen metabolism in plants. Decreased photosynthesis and nitrogenase activity, and altered plant's amino acid profile, with decreases in cell N concentrations, were observed. The removal of N from the growth medium accentuated the deleterious effects of Cipro, resulting in lower photosynthesis, N-fixation, and assimilation rates, and increased hydrogen peroxide accumulation. Our results shown that Cipro may constrain the use of Azolla as a biofertilizer species due to its interference with nitrogen fixation processes.

Attention has been paid to the environmental distribution and fate of nanomedicines. However, their effects on the toxicity of environmental pollutants are lack of knowledge. In this study, the negatively charged poly (ethylene glycol)-b-poly (L-lactide-co-glycolide) (mPEG-PLA) and positively charged polyethyleneimine-palmitate (PEI-PA) nanomicelles were synthesized and served as model drug carriers to study the interaction and combined toxicity with dichlorodiphenyltrichloroethane (DDT). DDT exerted limited effect on the biointerfacial behavior of mPEG-PLA nanomicelles, whereas it significantly mitigated the attachment of PEI-PA nanomicelles on the model cell membrane as monitored by quartz crystal microbalance with dissipation (QCM-D). The cytotoxicity of DDT towards NIH 3T3 cells was greatly decreased by either co-treatment or pre-treatment with the nanomicelles according to the results of real-time cell analysis (RTCA). The cell viability of NIH 3T3 exposed to DDT was increased up to 90% by the co-treatment with mPEG-PLA nanomicelles. Three possible reasons were proposed: (1) decreased amount of free DDT in the cell culture medium due to the partitioning of DDT into nanomicelles; (2) mitigated cellular uptake of nanomicelle-DDT complexes due to the complex agglomeration or electrostatic repulsion between complexes and cell membrane; (3) detoxification effect in the lysosome upon endocytosis of nanomicelle-DDT complexes.

The phenylurea herbicide, linuron (LIN), is used to control various types of weeds. Despite its efficient role in controlling weeds, it presents a persistent problem to the environment. In the current study, phytoremediation properties of transgenic CYP1A2 Arabidopsis thaliana plants to LIN were assessed. CYP1A2 gene was firstly cloned and expressed in bacteria before proceeding to plants. In presence of LIN, The growth of CYP1A2 expressing bacteria was superior compared to control bacteria transformed with the empty bacterial expression vector pET22b(+). No clear morphological changes were detected on CYP1A2 transgenic plants. However, significant resistance to LIN herbicide application either via spraying the foliar parts of the plant or via supplementation of the herbicide in the growth medium was observed for CYP1A2 transformants. Plant growth assays under LIN stress provide strong evidence for the enhanced capacity of transgenic lines to grow and to tolerate high concentrations of LIN compared to control plants. HPLC analyses showed that detoxification of LIN by bacterial extracts and/or transgenic plant leaves is improved as compared to the corresponding controls. Our data indicate that over expression of the human CYP1A2 gene increases the phytoremediation capacity and tolerance of Arabidopsis thaliana plants to the phenylurea herbicide linuron.

Drill cuttings leave behind thousands of tons of residues without adequate treatment, generating a large environmental liability. Therefore knowledge about the microbial community of drilling residue may be useful for developing bioremediation strategies. In this work, samples of drilling residue were enriched in different culture media in the presence of petroleum, aiming to select potentially oil-degrading bacteria and biosurfactant producers. Total DNA was extracted directly from the drill cutting samples and from two enriched consortia and sequenced using the Ion Torrent platform. Taxonomic analysis revealed the predominance of Proteobacteria in the metagenome from the drill cuttings, while Firmicutes was enriched in consortia samples. Functional analysis using the Biosurfactants and Biodegradation Database (BioSurfDB) revealed a similar pattern among the three samples regarding hydrocarbon degradation and biosurfactants production pathways. However, some statistical differences were observed between samples. Namely, the pathways related to the degradation of fatty acids, chloroalkanes, and chloroalkanes were enriched in consortia samples. The degradation colorimetric assay using dichlorophenolindophenol as an indicator was positive for several hydrocarbon substrates. The consortia were also able to produce biosurfactants, with biosynthesis of iturin, lichnysin, and surfactin among the more abundant pathways. A microcosms assay followed by gas chromatography analysis showed the efficacy of the consortia in degrading alkanes, as we observed a reduction of around 66% and 30% for each consortium in total alkanes. These data suggest the potential use of these consortia in the bioremediation of drilling residue based on autochthonous bioaugmentation.

The identification of airborne bacteria has traditionally been performed by retrieval in culture media, but the bacterial diversity in the air is underestimated using this method because many bacteria are not readily cultured. Advances in DNA sequencing technology have produced a broad knowledge of genomics and metagenomics, which can greatly improve our ability to identify and study the diversity of airborne bacteria. However, researchers are facing several challenges, particularly the efficient retrieval of low-density microorganisms from the air and the lack of standardized protocols for sample collection and processing. In this study, we tested three methods for sampling bioaerosols — a Durham-type spore trap (Durham), a seven-day recording volumetric spore trap (HST), and a high-throughput 'Jet' spore and particle sampler (Jet) — and recovered metagenomic DNA for 16S rDNA sequencing. Samples were simultaneously collected with the three devices during one week, and the sequencing libraries were analyzed. A simple and efficient method for collecting bioaerosols and extracting good quality DNA for high-throughput sequencing was standardized. The Durham sampler collected preferentially Cyanobacteria, the HST Actinobacteria, Proteobacteria and Firmicutes, and the Jet mainly Proteobacteria and Firmicutes. The HST sampler collected the largest amount of airborne bacterial diversity. More experiments are necessary to select the right sampler, depending on study objectives, which may require monitoring and collecting specific airborne bacteria.

This study describes the capacity of different sorbents to form stable biofilms under highly hydrocarbon-polluted conditions and the degrading capacity of the microbiota present in the biofilm. With this aim, microcosms were designed in a 1 L beaker with 400 mL of culture medium or polluted wastewater and an amount equivalent of 200 mL of the selected sorbent carrier, made of cork and/or polypropylene meltblown. The culturable bacteria adhered to the sorbent carrier were quantified, and the time course of the hydrocarbon concentration was studied together with the formation of a biofilm on the carrier’s surface. The results revealed a different performance of the carriers in terms of bacterial adhesion, significantly reduction in the hydrocarbon content in water at the end of the assays, and a biofilm tolerance to high hydrocarbon concentration in the polluted water. From these results, it was concluded that the use of a sorbent, hydrophobic cork, or meltblown polypropylene, together with indigenous microbiota, constitutes a promising technology for the treatment of hydrocarbon-polluted water.

Adult females of the estuarine crab Neohelice granulata were exposed during the 3-month pre-reproductive period (winter) to the herbicide glyphosate, the most used pesticide in Argentina, at three different concentrations (0.02, 0.2, and 1 mg/L, as active ingredient). At the end of the in vivo assay, the body weight gain and the ovarian growth were estimated, the last one in terms of the gonadosomatic index (GSI), the relative proportion of the different kind of oocytes, and their relative size. A decrease in the body weight gain was observed by effect of pure glyphosate, at all concentrations assayed. Although no differences in either the GSI or vitellogenic protein content of the ovary were noted between any glyphosate concentration and control, a higher proportion of reabsorbed vitellogenic oocytes was observed in the ovaries of crabs exposed to glyphosate at 1 mg/L, together with an increased area of previtellogenic oocytes. These effects were confirmed in vitro, at a glyphosate concentration of 0.2 mg/L. In fact, a higher area of previtellogenic oocytes was seen when glyphosate was added to the culture medium containing ovarian tissue, but a significant higher incidence of reabsorbed vitellogenic oocytes was seen only when eyestalk tissue was also added to the vials, suggesting that the secretion of some neurohormone involved in reabsorption is enhanced. The obtained results indicate that glyphosate is able to harm, in the studied species, both somatic and the ovarian growth.

In consideration of the hazards associated with the presence of the textile azo-dye and their biotransformation products in the environment, the goal of this work was to study bioremediation process by the yeast strain Pichia kudriavzevii CR-Y103 related to the ability to degrade and detoxify the sulfonated Reactive Orange 16 azo-dye. In experimental conditions, the optimal inoculum/dye concentration ratio required for complete decolorization (100%) of culture medium and biomass within 24 h has been 1 g L⁻¹ yeast cell (dry weight)/50 mg L⁻¹ Reactive Orange 16. In the presence of 400 mg L⁻¹ of Reactive Orange 16 (RO16), 95% of the dye was removed after 72 h of incubation. Also, the yeast strain could decolorize other eight textile dyes (56.48–99.98% decolorization within 24 h). NADH-DCIP reductase and azo reductase activities were significantly increased (ca. 5.4 times and ca. 37 times, respectively) during the decolorization process. UV-VIS spectra, high-performance liquid chromatography (HPLC), and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of new biotransformation products in extracted metabolites, highlighting the partial biodegradation of the dye by the new yeast isolate. The phytotoxicity evaluation strongly supported the decreased toxicity of biodegraded products as minor inhibition on germination (%), root and shoots elongation of T. pratense L. and T. aestivum L. seedlings. Increasing of mitotic index value and decreasing the frequency of chromosomal aberrations in tested plant meristem cells treated with biodegraded products, compared with RO16 treatment (500 ppm), confirmed their slightly toxic nature. A cell viability assay also confirmed the reduced toxicity of biodegraded products on healthy monkey kidney cells (Vero cells).

The generation of ozone microbubbles (O₃MB) is an effective means of sterilizing plant culture media against bacteria and pathogens; however, the use of O₃MB can induce precipitation of metal ions from the medium, such as iron (Fe) and manganese (Mn), that are important to plant growth. Here, we evaluated whether addition of a chelator, either ethylenediaminetetraacetic acid (EDTA) or diethylenetriaminepentaacetic acid (DTPA), could prevent this side effect of O₃MB sterilization. We compared nutrient composition, medium sterility, and plant growth after various treatments (0, 0.1, 0.01, 0.001, or 0.0001% (w/v) of EDTA and DTPA addition after O3MB generation). Metal chelators (EDTA and DTPA) are widely used in algal and plant growth solutions to maintain iron (Fe) solubility in hydroponic solutions, EDTA is used in agriculture to remove heavy metals from heavily contaminated soils and also as a plant fertilizer, and DTPA has a wide range of applications including removal of heavy metals from agricultural soils. Thus, the available evidence indicates that addition of a chelator after O₃MB generation may prevent precipitation of oxidized Fe or Mn in a culture medium. The addition of a chelator resulted in a concentration-dependent reduction in precipitates and the maintenance of Fe and Mn concentrations in the medium. Although O₃MB sterilization did not affect plant growth, the addition of a chelator at concentrations of 0.1, 0.01, or 0.001% (w/v) had a significant deleterious effect. However, at a concentration of 0.0001%, the chelator had no significant effect on plant growth but did result in the maintenance of a higher Fe and Mn concentration compared to the O₃MB treated control. The addition of a chelator did not alter the sterilizing effects of O₃MB. These results indicate that the addition of a chelator at a concentration of 0.0001% to an O₃MB-sterilized culture medium enabled the retention of dissolved Fe and Mn without affecting plant growth. The use of O₃MB, plus a chelator, is an effective disinfection method in hydroponic culture.

In this paper, coke wastewater that had passed through biological and integrated membrane processes (filtration on sand bed—reverse osmosis) was chosen to assess the phytotoxicity of selected industrial wastewater with regard to the test plant—Vicia faba. An innovative research technique in vitro test was conducted in a large scale phytothrone chamber on two matrices: cotton and Murashige and Skoog Basal Medium (MSBM). The toxicity of wastewater was evaluated for samples: (1) treated in the treatment plant by biological processes, (2) filtrated through a sand bed and filtrated (3) reverse osmosis (RO) membrane. The results showed that there is a noticeable correlation between increasing concentrations of wastewater and seed germination of the test plant. Although the wastewater collected from the coke plant was treated biologically, it showed very high levels of germination inhibition (90–98% for cotton matrix and 92–100% for MSBM matrix) and strong toxic effects. The wastewater collected from the coke plant showed a significantly greater phytotoxic effect compared with those obtained from the effluent treated on a sand bed and in RO. However, wastewater, even after treatment on a sand bed (reduction of COD—39%, TN—46%, TOC—42%, TC—47%, SS—50%, 16PAHs—53%), was still toxic and germination inhibition was in the range of 24–48% for the cotton matrix and 14–54% for the MSBM matrix. The toxicity of wastewater treated in the membrane process was the lowest (reduction of COD—85%, TN—95%, TOC—85%, TC—86%, SS—98%, 16PAHs—67%). The germination inhibition was in the range of 4–10% for the cotton matrix and 2–12% for the MSBM matrix. These samples are classified as non-toxic or slightly toxic to the model plant. The present study highlights the necessity of monitoring not only the basic physical and chemical indicators (including the level of toxic substances as PAHs), but also their effect on the test organisms in wastewater samples.