Polycyclic aromatic hydrocarbon-contaminated soils: bioaugmentation of autochthonous bacteria and toxicological assessment of the bioremediation process by means of Vicia faba L.

Two bacterial strains, Achromobacter sp. (ACH01) and Sphingomonas sp. (SPH01), were isolated from a heavily polycyclic aromatic hydrocarbon (PAH)-contaminated soil (5431.3 ± 102.3 ppm) for their capacity to use a mixture of anthracene, pyrene, phenanthrene and fluorene as sole carbon sources for growth and for the capacity to produce biosurfactants. The two strains were exploited for bioaugmentation in a biopile pilot plant to increase the bioavailability and the degradation of the residual PAH contamination (99.5 ± 7.1 ppm) reached after 9 months of treatment. The denaturing gel gradient electrophoresis (DGGE) profile of the microbial ecology of the soil during the experimentation showed that the bioaugmentation approach was successful in terms of permanence of the two strains in the soil in treatment. The bioaugmentation of the two bacterial isolates positively correlated with the PAH depletion that reached 7.9 ± 2 ppm value in 2 months of treatment. The PAH depletion was assessed by the loss of the phyto-genotoxicity of soil elutriates on the model plant Vicia faba L., toxicological assessment adopted also to determine the minimum length of the decontamination process for obtaining both the depletion of the PAH contamination and the detoxification of the soil at the end of the process. The intermediate phases of the bioremediation process were the most significant in terms of toxicity, inducing genotoxic effects and selective DNA fragmentation in the stem cell niche of the root tip. The selective DNA fragmentation can be related to the selective induction of cell death of mutant stem cells that can compromise offsprings

Mineral nutrients in soil and pea plants after exposition to TiO2 nanoparticles through a biosolid-amended soil

In addition to the benefits derived from nanotechnology, there is also concern about the potential risks of engineered nanoparticles (ENPs) when released into the environment. Their possible accumulation and effects in agricultural soils and Nanonnovation 2018 Conference & Exibition crops are closely linked to food and agriculture safety. Particular attention has been focused on the reuse of biosolids from wastewater treatment plants that are considered a cost-effective practice for the improvement of nutrients and organic matter in agricultural soils and, but also a sink of contaminants such as nanoparticles (NPs). TiO2NPs have a global production of about 10.000 tons/year and it are among the most extensively used ENPs. Moreover, dissimilar or inconclusive results have been reported concerning the impact of TiO2 NPs on the soil-crop system, thus more information regarding their behavior are necessary. This study aimed to evaluate the potential effects of TiO2 NPs (anatase and rutile) and larger particles (bulk) on the availability of soil nutrients and on the nutritional status of Pisum sativum plants, simulating low (80 mg/kg) and high load of TiO2 (800 mg/kg ) in a biosolid-amended soil. Treated soils were analyzed for N, P, K, Ca, Mg, Mn, Fe, Cu, Zn, soil microbial community, and plants grown in laboratory for 30d were analyzed for growth, pigments and mineral nutrition. Results showed that the treatment with TiO2 at macro- and nano-scale significantly reduced the availability of Mn, Fe and P in soils, this last more evident for the NPs treatments. Indeed, the soil bacterial diversity was reduced when the mixture of anatase and rutile were spiked in the biosolid-amended soil at high concentration. Moreover, the pea plants from treated soils showed an imbalance in the mineral nutrition, with reduction in the plant tissues of Mn and K and increase of N. This study pose a reflection on the use of biosolid, which could act as a vehicle for the spread and accumulation of ENPs in agro-ecosystems

Pleurotus ostreatus spent mushroom substrate for the degradation of polycyclic aromatic hydrocarbons: the case study of a pilot dynamic biopile for the decontamination of a historically contaminated soil

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are hazardous contaminants. Bio-based technology is among recommended practices for the recovery of PAH contaminatedmatrices. The objective of the study was to validate the exploitation of spent mushroom substrate (SMS), an organic waste deriving from the industrial production of Pleurotus ostreatus, as bulking agent in a dynamic biopile pilot plant, because of the SMS potential oxidative capacity towards aromatic recalcitrant compounds. The dynamic biopile pilot plant treated 7 tons of a historically PAH contaminated soil (6469±423mg PAHs kg−1), classified as dangerous waste. RESULTS: Themixing of SMSwith soilwasmandatory for the depletion of PAHs, which after 8months,were at significantly lower concentrations (112±5mg PAHs kg−1). The treated soil was capable of reintroduction to the industrial site of origin. However, a residual genotoxicity of soil elutriates at the end of the process wasmeasured on root tips of Vicia faba L. CONLUSIONS: The SMS derived from the industrial production of P. ostreatus is exploitable as a versatile low cost organic substrate with oxidative capacity towards PAHs and its exploitation as a bulking agent in biopiles is advantageous for the disposal of the organic waste

Hif1α down-regulation is associated with transposition of great arteries in mice treated with a retinoic acid antagonist

<p>Abstract</p> <p>Background</p> <p>Congenital heart defect (CHD) account for 25% of all human congenital abnormalities. However, very few CHD-causing genes have been identified so far. A promising approach for the identification of essential cardiac regulators whose mutations may be linked to human CHD, is the molecular and genetic analysis of heart development. With the use of a triple retinoic acid competitive antagonist (BMS189453) we previously developed a mouse model of congenital heart defects (81%), thymic abnormalities (98%) and neural tube defects (20%). D-TGA (D-transposition of great arteries) was the most prevalent cardiac defect observed (61%). Recently we were able to partially rescue this abnormal phenotype (CHD were reduced to 64.8%, p = 0.05), by oral administration of folic acid (FA). Now we have performed a microarray analysis in our mouse models to discover genes/transcripts potentially implicated in the pathogenesis of this CHD.</p> <p>Results</p> <p>We analysed mouse embryos (8.5 dpc) treated with BMS189453 alone and with BMS189453 plus folic acid (FA) by microarray and qRT-PCR. By selecting a fold change (FC) ≥ ± 1.5, we detected 447 genes that were differentially expressed in BMS-treated embryos vs. untreated control embryos, while 239 genes were differentially expressed in BMS-treated embryos whose mothers had also received FA supplementation vs. BMS-treated embryos. On the basis of microarray and qRT-PCR results, we further analysed the <it>Hif1α </it>gene. In fact <it>Hif1α </it>is down-regulated in BMS-treated embryos vs. untreated controls (FC_micro= -1.79; FC_qRT-PCR= -1.76; p = 0.005) and its expression level is increased in BMS+FA-treated embryos compared to BMS-treated embryos (FC_micro= +1.17; FC_qRT-PCR= +1.28: p = 0.005). Immunofluorescence experiments confirmed the under-expression of Hif1α protein in BMS-treated embryos compared to untreated and BMS+FA-treated embryos and, moreover, we demonstrated that at 8.5 dpc, Hif1α is mainly expressed in the embryo heart region.</p> <p>Conclusions</p> <p>We propose that Hif1α down-regulation in response to blocking retinoic acid binding may contribute to the development of cardiac defects in mouse newborns. In line with our hypothesis, when Hif1α expression level is restored (by supplementation of folic acid), a decrement of CHD is found. To the best of our knowledge, this is the first report that links retinoic acid metabolism to Hif1α regulation and the development of D-TGA.</p

RECOVERING OF DREDGED SEDIMENTS CONTAMINATED BY TOTAL PETROLEUM HYDROCARBON TO PRODUCTIVE SOILS: THE MYCOREMEDIATION APPROACH IN THE BIORESNOVA PROJECT

Chemo-physical treatments to remove salinity and metal contamination from dredged sediments were applied in combination to bio-based approaches (mycoremediation). New fungal specimen were isolated from the contaminated sediments, massively grown and re-inoculated in the matrix in treatment to remove the Total Petroleum Hydrocarbon contamination (TPH). Toxicological assays were exploited to estimate the sediment remediation efficiency over time. Indeed, the only chemical characterization of polluted matrices does not allow to predict the residual toxicity of the latter eventually related to the permanence of a residual contamination by the parental pollutants, to their degradation intermediates and/or to the synergic actions of the both. Higher plants (Vicia faba L.) were exploited as indicators of the quality of the treated sediments and used both for the continuous monitoring of the remediation processes and for the evaluation of the final product eco-safety. Biological parameters such as the genotoxicity by means of cytological analysis of mitotic behavior of root meristems were evaluated based on the detection of chromosomal aberrations in mitotic cells, and of micronuclei formation, detectable in interphase cells. The combination of the Chemo-physical and the Bio-based approach was able to remove the organic contamination (TPH) and the excess of sodium salts that constitute a critical point for the eventual re-allocation of dredged sediments. At the same time the sediments were detoxified and actually gained the biochemical traits of humified productive soils, eventually suitable for their safe re-allocation in the environment

A New Ciboria sp. for Soil Mycoremediation and the Bacterial Contribution to the Depletion of Total Petroleum Hydrocarbons

A Ciboria sp. strain (Phylum Ascomycota) was isolated from hydrocarbon-polluted soil of an abandoned oil refinery in Italy. The strain was able to utilize diesel oil as a sole carbon source for growth. Laboratory-scale experiments were designed to evaluate the use of this fungal strain for treatment of the polluted soil. The concentration of total petroleum hydrocarbons (TPH) in the soil was 8,538 mg/kg. Mesocosms containing the contaminated soil were inoculated with the fungal strain at 1 or 7%, on a fresh weight base ratio. After 90 days of incubation, the depletion of TPH contamination was of 78% with the 1% inoculant, and 99% with the 7% inoculant. 16S rDNA and ITS metabarcoding of the bacterial and fungal communities was performed in order to evaluate the potential synergism between fungi and bacteria in the bioremediation process. The functional metagenomic prediction indicated Arthrobacter, Dietzia, Brachybacerium, Brevibacterium, Gordonia, Leucobacter, Lysobacter, and Agrobacterium spp. as generalist saprophytes, essential for the onset of hydrocarbonoclastic specialist bacterial species, identified as Streptomyces, Nocardoides, Pseudonocardia, Solirubrobacter, Parvibaculum, Rhodanobacter, Luteiomonas, Planomicrobium, and Bacillus spp., involved in the TPH depletion. The fungal metabolism accelerated the onset of specialist over generalist bacteria. The capacity of the Ciboria sp. to deplete TPH in the soil in treatment was also ascertained