Search

Sepsis‐induced metabolic dysfunction contributes to organ failure and death. L‐carnitine has shown promise for septic shock, but a recent phase II study of patients with vasopressor‐dependent septic shock demonstrated a non‐significant reduction in mortality. We undertook a pharmacometabolomics study of these patients (n = 250) to identify metabolic profiles predictive of a 90‐day mortality benefit from L‐carnitine. The independent predictive value of each pretreatment metabolite concentration, adjusted for L‐carnitine dose, on 90‐day mortality was determined by logistic regression. A grid‐search analysis maximizing the Z‐statistic from a binomial proportion test identified specific metabolite threshold levels that discriminated L‐carnitine responsive patients. Threshold concentrations were further assessed by hazard ratio and Kaplan‐Meier estimate. Accounting for L‐carnitine treatment and dose, 11 1H‐NMR metabolites and 12 acylcarnitines were independent predictors of 90‐day mortality. Based on the grid‐search analysis numerous acylcarnitines and valine were identified as candidate metabolites of drug response. Acetylcarnitine emerged as highly viable for the prediction of an L‐carnitine mortality benefit due to its abundance and biological relevance. Using its most statistically significant threshold concentration, patients with pretreatment acetylcarnitine greater than or equal to 35 µM were less likely to die at 90 days if treated with L‐carnitine (18 g) versus placebo (p = 0.01 by log rank test). Metabolomics also identified independent predictors of 90‐day sepsis mortality. Our proof‐of‐concept approach shows how pharmacometabolomics could be useful for tackling the heterogeneity of sepsis and informing clinical trial design. In addition, metabolomics can help understand mechanisms of sepsis heterogeneity and variable drug response, because sepsis induces alterations in numerous metabolite concentrations.

Mupirocin is a clinically important antibiotic produced by Pseudomonas fluorescens NCIMB 10586 that is assembled by a complex trans-AT polyketide synthase. The polyketide fragment, monic acid, is esterified by a 9-hydroxynonanoic acid (9HN) side chain which is essential for biological activity. The ester side chain assembly is initialised from a 3-hydroxypropionate (3HP) starter unit attached to the acyl carrier protein (ACP) MacpD, but the fate of this species is unknown. Herein we report the application of NMR spectroscopy, mass spectrometry, chemical probes and in vitro assays to establish the remaining steps of 9HN biosynthesis. These investigations reveal a complex interplay between a novel iterative or "stuttering" KS-AT didomain (MmpF), the multidomain module MmpB and multiple ACPs. This work has important implications for understanding the late-stage biosynthetic steps of mupirocin and will be important for future engineering of related trans-AT biosynthetic pathways (e.g. thiomarinol). ispartof: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION vol:61 issue:50 ispartof: location:Germany status: published

Background Oral administration of purified omega-3 (ω-3) PUFAs is associated with changes to the fecal microbiome. However, it is not known whether this effect is associated with increased PUFA concentrations in the gut. Objectives We investigated the luminal bioavailability of oral ω-3 PUFAs (daily dose 1 g EPA and 1g DHA free fatty acid equivalents as triglycerides in soft-gel capsules, twice daily) and changes to the gut microbiome, in the ileum. Methods Ileostomy fluid (IF) and blood were obtained at baseline, after first capsule dosing (median 2 h), and at a similar time after final dosing on day 28, in 11 individuals (median age 63 y) with a temporary ileostomy. Fatty acids were measured by LC–tandem MS. The ileal microbiome was characterized by 16S rRNA PCR and Illumina sequencing. Results There was a mean 6.0 ± 9.8-fold and 6.6 ± 9.6-fold increase in ileal EPA and DHA concentrations (primary outcome), respectively, at 28 d, which was associated with increased RBC ω-3 PUFA content (P ≤ 0.05). The first oral dose did not increase the ileal ω-3 PUFA concentration except in 4 individuals, who displayed high luminal EPA and DHA concentrations, which reduced to concentrations similar to the overall study population at day 28, suggesting physiological adaptation. Bacteroides, Clostridium, and Streptococcus were abundant bacterial genera in the ileum. Ileal microbiome variability over time and between individuals was large, with no consistent change associated with acute ω-3 PUFA dosing. However, high concentrations of EPA and DHA in IF on day 28 were associated with higher abundance of Bacteroides (r2 > 0.86, P 0.94, P

The synthesis of new Schrock–Osborn Rh(i) pre-catalysts with ortho-substituted DPEphos ligands, [Rh(DPEphos-R)(NBD)][BArF4] [R = Me, OMe, iPr; ArF = 3,5-(CF3)2C6H3], is described. Along with the previously reported R = H variant, variable temperature 1H NMR spectroscopic and single-crystal X-ray diffraction studies show that these all have axial (C–H)⋯Rh anagostic interactions relative to the d8 pseudo square planar metal centres, that also result in corresponding downfield chemical shifts. Analysis by NBO, QTAIM and NCI methods shows these to be only very weak C–H⋯Rh bonding interactions, the magnitudes of which do not correlate with the observed chemical shifts. Instead, as informed by Scherer's approach, it is the topological positioning of the C–H bond with regard to the metal centre that is important. For [Rh(DPEphos–iPr)(NBD)][BArF4] addition of H2 results in a Rh(iii) iPr–C–H activated product, [Rh(κ3,σ-P,O,P-DPEphos-iPr′)(H)][BArF4]. This undergoes H/D exchange with D2 at the iPr groups, reacts with CO or NBD to return Rh(i) products, and reaction with H3B·NMe3/tert-butylethene results in a dehydrogenative borylation to form a complex that shows both a non-classical B–H⋯Rh 3c-2e agostic bond and a C–H⋯Rh anagostic interaction at the same metal centre., Rh(i) complexes of ortho-substituted DPEphos-R (R = H, Me, OMe, iPr) ligands show anagostic interactions; for R =iPr C–H activation/dehydrogenative borylation forms a product exhibiting both B–H/Rh 3c-2e agostic and C–H/Rh anagostic motifs.

A more complete and holistic view on host-microbe interactions is needed to understand the physiological and cellular barriers that affect the efficacy of drug treatments and allow the discovery and development of new therapeutics. Here, we developed a multimodal imaging approach combining histopathology with mass spectrometry imaging (MSI) and same section imaging mass cytometry (IMC) to study the effects of Salmonella Typhimurium infection in the liver of a mouse model using the S. Typhimurium strains SL3261 and SL1344. This approach enables correlation of tissue morphology and specific cell phenotypes with molecular images of tissue metabolism. IMC revealed a marked increase in immune cell markers and localization in immune aggregates in infected tissues. A correlative computational method (network analysis) was deployed to find metabolic features associated with infection and revealed metabolic clusters of acetyl carnitines, as well as phosphatidylcholine and phosphatidylethanolamine plasmalogen species, which could be associated with pro-inflammatory immune cell types. By developing an IMC marker for the detection of Salmonella LPS, we were further able to identify and characterize those cell types which contained S. Typhimurium.

Imaging mass cytometry (IMC) offers the opportunity to image metal- and heavy halogen-containing xenobiotics in a highly multiplexed experiment with other immunochemistry-based reagents to distinguish uptake into different tissue structures or cell types. However, in practice, many xenobiotics are not amenable to this analysis, as any compound which is not bound to the tissue matrix will delocalize during aqueous sample-processing steps required for IMC analysis. Here, we present a strategy to perform IMC experiments on a water-soluble polysarcosine-modified dendrimer drug-delivery system (S-Dends). This strategy involves two consecutive imaging acquisitions on the same tissue section using the same instrumental platform, an initial laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MSI) experiment followed by tissue staining and a standard IMC experiment. We demonstrated that settings can be found for the initial ablation step that leave sufficient residual tissue for subsequent antibody staining and visualization. This workflow results in lateral resolution for the S-Dends of 2 μm followed by imaging of metal-tagged antibodies at 1 μm.

Accumulation of misfolded host proteins is central to neuropathogenesis of numerous human brain diseases including prion and prion-like diseases. Neurons of retina are also affected by these diseases. Previously, our group and others found that prion-induced retinal damage to photoreceptor cells in mice and humans resembled pathology of human retinitis pigmentosa caused by mutations in retinal proteins. Here, using confocal, epifluorescent and electron microscopy we followed deposition of disease-associated prion protein (PrPSc) and its association with damage to critical retinal structures following intracerebral prion inoculation. The earliest time and place of retinal PrPSc deposition was 67 days post-inoculation (dpi) on the inner segment (IS) of cone photoreceptors. At 104 and 118 dpi, PrPSc was associated with the base of cilia and swollen cone inner segments, suggesting ciliopathy as a pathogenic mechanism. By 118 dpi, PrPSc was deposited in both rods and cones which showed rootlet damage in the IS, and photoreceptor cell death was indicated by thinning of the outer nuclear layer. In the outer plexiform layer (OPL) in uninfected mice, normal host PrP (PrPC) was mainly associated with cone bipolar cell processes, but in infected mice, at 118 dpi, PrPSc was detected on cone and rod bipolar cell dendrites extending into ribbon synapses. Loss of ribbon synapses in cone pedicles and rod spherules in the OPL was observed to precede destruction of most rods and cones over the next 2–3 weeks. However, bipolar cells and horizontal cells were less damaged, indicating high selectivity among neurons for injury by prions. PrPSc deposition in cone and rod inner segments and on the bipolar cell processes participating in ribbon synapses appear to be critical early events leading to damage and death of photoreceptors after prion infection. These mechanisms may also occur in human retinitis pigmentosa and prion-like diseases, such as AD.

We assessed whether soil with high Cr contamination could be reclaimed by alkali, mineral, and organic acid-based ligands (OABLs) washing. We tested HNO3, H2SO4, HCl, NaOH, H2O2, lactic acid (LA), malic acid (MA), oxalic acid (OA), and citric acid (CA), together with EDTA, obtaining the highest efficiencies in presence of 1 M sulfuric acid (98%). Nonetheless we noted that using OABLs, we obtained a Cr(III) removal efficiency similar to the one obtained using mineral acids. Indeed 1 M of LA and MA and 0.8 M of OA allowed obtaining, respectively, 88%, 75%, and 67% removal percentage. The extraction process with OABLs was strongly dependent on intraparticle diffusion of Cr-LA, Cr-MA, and Cr-OA complexes. We also determined the apparent diffusion coefficients. Residual toxicity of treated soils was tested with the nematode, Caenorhabditis elegans. The OABL washing generally allowed getting a soil without Cr and with reduced toxicity. However, the washing process also removed other cations that acted as nutrients. Consequently, we conducted toxicity tests on enriched soil and found that the mortality index improved. In some cases (LA and MA), mortality was comparable to that observed with uncontaminated control samples. In contrast, when contaminated soils were washed with sulfuric acid, in all conditions, we observed significant ecotoxicity. Therefore, we concluded that only the OABL treatment provided a non-toxic soil that could be reused for anthropic activities.

International audience; We present a new cell membrane modification methodology where the inherent heart tissue homing properties of the infectious bacteria Streptococcus gordonii are transferred to human stem cells. This is achieved via the rational design of a chimeric protein-polymer surfactant cell membrane binding construct, comprising the cardiac fibronectin (Fn) binding domain of the bacterial adhesin protein CshA fused to a supercharged protein. Significantly, the protein-polymer surfactant hybrid spontaneously inserts into the plasma membrane of stem cells without cytotoxicity, instilling the cells with a high affinity for immobilized fibronectin. Moreover, we show that this cell membrane reengineering approach significantly improves retention and homing of stem cells delivered either intracardially or intravenously to the myocardium in a mouse model.

PurposeThe naturally-occurring omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) is safe, well-tolerated and inexpensive, making it an attractive anti-cancer intervention. However, EPA has only modest anti-colorectal cancer (CRC) activity, when used alone. Both cyclooxygenase (COX) isoforms metabolise EPA and are over-expressed in CRC cells. We investigated whether COX inhibition increases the sensitivity of CRC cells to growth inhibition by EPA.MethodsA panel of 18 human and mouse CRC cell lines was used to characterize the differential sensitivity of CRC cells to the growth inhibitory effects of EPA. The effect of CRISPR-Cas9 genetic deletion and pharmacological inhibition of COX-1 and COX-2 on the anti-cancer activity of EPA was determined using in vitro and in vivo models.ResultsGenetic ablation of both COX isoforms increased sensitivity of CT26 mouse CRC cells to growth inhibition by EPA in vitro and in vivo. The non-selective COX inhibitor aspirin and the selective COX-2 inhibitor celecoxib increased sensitivity of several human and mouse CRC cell lines to EPA in vitro. However, in a MC38 mouse CRC cell tumour model, with dosing that mirrored low-dose aspirin use in humans, thereby producing significant platelet COX-1 inhibition, there was ineffective intra-tumoral COX-2 inhibition by aspirin and no effect on EPA sensitivity of MC38 cell tumours.ConclusionCyclooxygenase inhibition by non-steroidal anti-inflammatory drugs represents a therapeutic opportunity to augment the modest anti-CRC activity of EPA. However, intra-tumoral COX inhibition is likely to be critical for this drug-nutrient interaction and careful tissue pharmacodynamic profiling is required in subsequent pre-clinical and human studies.

Formation of phenonium ions through anchimeric assistance (neighboring-group participation) of aryl rings has been known since 1949. Although these reactive intermediates have been studied extensively by physical organic chemists, their potential as control elements in synthesis is underutilized. Presented here are our laboratory’s recently reported first examples of regiodivergent openings of nonsymmetrical phenonium ions with chloride nucleophiles. The selectivity of these processes is under reagent control. The reactions are operationally simple and permit the stereospecific synthesis of complex chiral building blocks from readily accessible epoxide starting materials.1 Introduction2 Select Examples of Phenonium Ion Methodology3 Regiodivergent Opening of Nonsymmetrical Phenonium Ions4 Summary and Outlook

A detailed study of H3B·NMeH2 dehydropolymerization using the cationic precatalyst [Rh(DPEphos)(H2BNMe3(CH2)2tBu)][BArF4] identifies the resting state as dimeric [Rh(DPEphos)H2]2 and boronium [H2B(NMeH2)2]+ as the chain-control agent. [Rh(DPEphos)H2]2 can be generated in situ from Rh(DPEphos)(benzyl) and catalyzes polyaminoborane formation (H2BNMeH)n [Mn = 15 000 g mol–1]. Closely related Rh(Xantphos)(benzyl) operates at 0.1 mol % to give a higher molecular weight polymer [Mn = 85 000 g mol–1] on the gram scale with low residual [Rh], 81 ppm. This insight offers a mechanistic template for dehydropolymerization.

With growing understanding of the underlying pathways of polyketide biosynthesis, along with the continual expansion of the synthetic biology toolkit, it is becoming possible to rationally engineer and fine-tune the polyketide biosynthetic machinery for production of new compounds with improved properties such as stability and/or bioactivity. However, engineering the pathway to the thiomarinol antibiotics has proved challenging. Here we report that genes from a marine Pseudoalternomonas sp. producing thiomarinol can be expressed in functional form in the biosynthesis of the clinically important antibiotic mupirocin from the soil bacterium Pseudomonas fluorescens. It is revealed that both pathways employ the same unusual mechanism of tetrahydropyran (THP) ring formation and the enzymes are cross compatible. Furthermore, the efficiency of downstream processing of 10,11-epoxy versus 10,11-alkenic metabolites are comparable. Optimisation of the fermentation conditions in an engineered strain in which production of pseudomonic acid A (with the 10,11-epoxide) is replaced by substantial titres of the more stable pseudomonic acid C (with a 10,11-alkene) pave the way for its development as a more stable antibiotic with wider applications than mupirocin., Where the sea meets the land: the mupirocin biosynthetic gene cluster (BGC) from the terrestrial bacterium Pseudomonas fluorescens was repurposed via a plug-and-play approach with heterologous genes from the marine strain that produces thiomarinol.

The cell surfaces of many bacteria carry filamentous polypeptides termed adhesins that enable binding to both biotic and abiotic surfaces. Surface adherence is facilitated by the exquisite selectivity of the adhesins for their cognate ligands or receptors and is a key step in niche or host colonization and pathogenicity. Streptococcus gordonii is a primary colonizer of the human oral cavity and an opportunistic pathogen, as well as a leading cause of infective endocarditis in humans. The fibrillar adhesin CshA is an important determinant of S. gordonii adherence, forming peritrichous fibrils on its surface that bind host cells and other microorganisms. CshA possesses a distinctive multidomain architecture comprising an N-terminal target-binding region fused to 17 repeat domains (RDs) that are each ∼100 amino acids long. Here, using structural and biophysical methods, we demonstrate that the intact CshA repeat region (CshA_RD1–17, domains 1–17) forms an extended polymeric monomer in solution. We recombinantly produced a subset of CshA RDs and found that they differ in stability and unfolding behavior. The NMR structure of CshA_RD13 revealed a hitherto unreported all β-fold, flanked by disordered interdomain linkers. These findings, in tandem with complementary hydrodynamic studies of CshA_RD1–17, indicate that this polypeptide possesses a highly unusual dynamic transitory structure characterized by alternating regions of order and disorder. This architecture provides flexibility for the adhesive tip of the CshA fibril to maintain bacterial attachment that withstands shear forces within the human host. It may also help mitigate deleterious folding events between neighboring RDs that share significant structural identity without compromising mechanical stability.

We report the first examples of selective and regiodivergent opening of unsymmetrical phenonium ions with chloride ions. These reactions are enabled by the dual role of SnCl4 and TiCl4 as Lewis acids and chloride nucleophiles. Reagent control dictates addition of chloride at either the substituted internal position (SnCl4) or unsubstituted terminal position (TiCl4) of the phenonium ion. These reactions are highly selective, stereospecific, operationally simple, and proceed in good to excellent yields. Diverse product utility is demonstrated.

Mupirocin, a commercially available antibiotic produced by Pseudomonas fluorescens NCIMB 10586, and thiomarinol, isolated from the marine bacterium Pseudoalteromonas sp. SANK 73390, both consist of a polyketide-derived monic acid homologue esterified with either 9-hydroxynonanoic acid (mupirocin, 9HN) or 8-hydroxyoctanoic acid (thiomarinol, 8HO). The mechanisms of formation of these deceptively simple 9HN and 8HO fatty acid moieties in mup and tml, respectively, remain unresolved. To define starter unit generation, the purified mupirocin proteins MupQ, MupS, and MacpD and their thiomarinol equivalents (TmlQ, TmlS and TacpD) have been expressed and shown to convert malonyl coenzyme A (CoA) and succinyl CoA to 3-hydroxypropionoyl (3-HP) or 4-hydroxybutyryl (4-HB) fatty acid starter units, respectively, via the MupQ/TmlQ catalyzed generation of an unusual bis-CoA/acyl carrier protein (ACP) thioester, followed by MupS/TmlS catalyzed reduction. Mix and match experiments show MupQ/TmlQ to be highly selective for the correct CoA. MacpD/TacpD were interchangeable but alternate trans-acting ACPs from the mupirocin pathway (MacpA/TacpA) or a heterologous ACP (BatA) were nonfunctional. MupS and TmlS selectivity was more varied, and these reductases differed in their substrate and ACP selectivity. The solution structure of MacpD determined by NMR revealed a C-terminal extension with partial helical character that has been shown to be important for maintaining high titers of mupirocin. We generated a truncated MacpD construct, MacpD_T, which lacks this C-terminal extension but retains an ability to generate 3-HP with MupS and MupQ, suggesting further downstream roles in protein–protein interactions for this region of the ACP

Soil contamination by pyrene has increased over the years due to human-related activities, urgently demanding for remediation approaches to ensure human and environment safety. Within this frame, phytoremediation has been successfully applied over the years due to its green and cost-effectiveness features. The scope of this review includes the main phytoremediation mechanisms correlated with the removal of pyrene from contaminated soils and sediments to highlight the impact of different parameters and the supplement of additives on the efficiency of the treatment. Soil organic matter (SOM), plant species, aging time, environmental parameters (pH, soil oxygenation, and temperature) and bioavailability are among the main parameters affecting pyrene removal through phytoremediation. Phytoextraction only accounts for a small part of the entire phytoremediation process, but the addition of surfactants and chelating agents in planted soils could increase pyrene accumulation in plant tissues by 20% as a consequence of the increased pyrene bioavailability. Rhizodegradation is the main phytoremediation mechanism involved due to the activity of bacteria capable of degrading pyrene in the root area. Inoculated-planted soil treatments have the potential to decrease pyrene accumulation in shoots and roots by approximately 30 and 40%, respectively, further stimulating the proliferation of pyrene-degrading bacteria in the rhizosphere. Plant-fungi symbiotic association results in an enhanced accumulation of pyrene in shoots and roots of plants as well as a higher biodegradation. Finally, pyrene removal from soil can be improved in the presence of amendments, such as natural non-ionic surfactants, biochar, and bacterial mixtures.

Water splitting for renewable energy technologies necessitates the creation of low-cost, highly active, and stable electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which remains a challenging issue. Oxide-based catalysts, especially perovskites (ABO3), ruddlesden–popper perovskite (A2BO4) and pyrochlore-type oxides (A2B2O7), have attracted gotten much interest as electrocatalysts for water splitting because of their distinctive physical, chemical, and electronic properties. In this work, a scientometric analysis is conducted on developing various oxide-based catalysts for water splitting to explore further developments. Up to now, a total of 29,761 publications (between the years 1990–2020) have been obtained from the Web of Science (WoS) website by searching for these written documents on this subject with a variety of linking keywords. The derived documents were subjected to a scientometric study, which included a look at the contributing authors, publications, contributing countries, top citation bursts, and topic categories. Based on the information obtained, in this research area, the publications started to increase dramatically since 2012. In terms of scientific output on oxide-based catalysts for water splitting, China and the United States were discovered to be the world leaders.

Significant release of rare earth elements (REEs) into the environment is mainly due to active or abandoned mining sites, but their presence is globally increasing due to their use in several industrial sectors. The effects on primary producers as Raphidocelis subcapitata are still limited. This research focused on La and Ce as the two most widespread REEs that can be currently found up to hundreds of μg/L in water and wastewater. Microalgae were exposed to La and Ce for 3 days (pH = 7.8) (short-term exposure) to derive the effective concentrations inhibiting the growth on 10% (EC10) of the exposed population. EC10 values (0.5 mg/L of La and 0.4 mg/L of Ce) were used for the 28 days long-term exposure (renewal test) to observe after 7, 14, 21, and 28 days on a multi-endpoint basis microalgae growth inhibition (GI), biomarkers of stress (reactive oxygen species (ROS), superoxide dismutase (SOD), and catalase (CAT)), and bioconcentration. Results evidenced that La and Ce EC10 increased GI (day 28) up to 38% and 28%, respectively. ROS, CAT, and SOD activities showed differential responses from day 7 to day 14, 21, and 28, suggesting, in most of the cases, that La and Ce effects were counteracted (i.e., being the values at day 28 not significantly different, p > 0.05, from the relative negative controls), except for La-related ROS activities. La and Ce significantly bioconcentrated in microalgae populations up to 2- and 5-fold (i.e., at day 28 compared to day 7), in that order. Bioconcentrated La and Ce were up to 3157 and 1232 μg/g dry weight (day 28), respectively. These results suggested that low La and Ce concentrations can be slightly toxic to R. subcapitata having the potential to be bioaccumulated and potentially transferred along the food web.

The continuous dredging of sediments contaminated by polycyclic aromatic hydrocarbons such as phenanthrene (PHE) has required the employment of high–efficiency technologies, including sediment washing (SW). However, the large amount of generated spent SW effluents requires the development of effective, eco–friendly and cost–saving approaches, which can tackle the waste formation in favor of the recovery of chemicals. This study proposes the treatment of a spent SW solution containing ethanol (EtOH) as extracting agent, by testing different initial PHE concentrations (i.e. 20–140 mg L−1) within six consecutive cycles in a fed–batch bioreactor under aerobic conditions. The biological process achieved a PHE removal of 63–91% after the enrichment of PHE–degrading bacteria and the proper supplementation of nutrients, and was mainly affected by the initial PHE concentration value and the excessive decrease of pH and dissolved oxygen. Achromobacter, Sphingobacterium and Dysgonomonas genera were mainly involved in PHE degradation, which followed a first–order kinetic model (R2 = 0.652–0.928) with a degradation rate and half–life time of 0.127–1.177 d−1 and 0.589–2.912 d, respectively. A techno–economic assessment revealed that a virtuous operation of SW, EtOH recovery and biodegradation of the SW solution can allow the recovery of up to 1.35 tons of EtOH per ton of remediated sediment and the decrease of the overall costs by 50%.

Many opportunistic bacteria that infect the upper respiratory tract decorate their cell surface with phosphorylcholine to support colonisation and outgrowth. These surface modifications require the active import of choline from the host environment, a process thought to be mediated by a family of dedicated integral membrane proteins that act as choline permeases. Here, we present the expression and purification of the archetype of these choline transporters, LicB from Haemophilus influenzae. We show that LicB can be recombinantly produced in Escherichia coli and purified to homogeneity in a stable, folded state using the detergent n-dodecyl-β- d -maltopyranoside. Equilibrium binding studies with the fluorescent ligand dansylcholine suggest that LicB is selective towards choline, with reduced affinity for acetylcholine and no apparent activity towards other small molecules including glycine, carnitine and betaine. We also identify a conserved sequence motif within the LicB family and show that mutations within this motif compromise protein structure and function. Our results are consistent with previous observations that LicB is a specific high-affinity choline transporter, and provide an experimental platform for further studies of this permease family.

It is proposed a closed-loop treatment cycle for Cr(III) removal from contaminated soils (2080 mg/kg). The treatment includes the use of lactic acid as washing agent, and the recovery of both Cr(II) and lactic acid from the spent solution. Results indicate that Cr(III) removal efficiency can be very high, passing 70% in all tested operative conditions. The metal forms strong complexes with lactic acid, and therefore cannot be eliminated through direct precipitation simply increasing the pH value. Therefore, lactic acid is preliminarily extracted from the solution using n-butanol at very acidic pH. The obtained extraction degree is generally high, varying between 0.5 and 1 according to the amount of used n-butanol solution. After lactic acid extraction, almost 100% of chromium can be recovered through precipitation in alkaline conditions. Lactic acid, in turns, can be purified and reused for a new washing treatment, separating it from n-butanol solution through water extraction. The extraction efficiency is once more satisfying (around 0.5), and not dependent on the operative pH.

This study proposes the supplementation of digestate, fresh organic fraction of municipal solid waste (OFMSW) and a nutrient solution during the anaerobic biostimulation of marine sediments contaminated by polycyclic aromatic hydrocarbons (PAHs). The experimental activity was conducted with four PAHs (i.e. phenanthrene, anthracene, fluoranthene and pyrene) under controlled mesophilic conditions (37 ± 1 °C) in 100 mL serum bottles maintained at 130 rpm. After 120 days of incubation, the highest total PAH degradation of 53 and 55% was observed in the experiments with digestate + nutrients and OFMSW + nutrients, respectively. Phenanthrene was the most degraded PAH and the highest removal of 69% was achieved with OFMSW + nutrients. The anaerobic PAH degradation proceeded through the accumulation of volatile fatty acids and the production of hydrogen and methane as biogas constituents. The highest cumulative biohydrogen production of 80 mL H2·g VS−1 was obtained when OFMSW was used as the sole amendment, whereas the highest biomethane yield of 140 mL CH4·g VS−1 was obtained with OFMSW + nutrients. The evolution of PAH removal during anaerobic digestion revealed a higher impact of the methanogenic phase rather than acidogenic phase on PAH degradation.

Buried pipelines transporting dense phase Carbon dioxide CO2 are crucial to carbon reduction and climate change mitigating technologies such as Carbon Capture and Storage (CCS) and Carbon Capture Utilization and Storage (CCUS). One of the major challenges for optimum pipeline operating conditions is to avoid phase change of the compressed CO2 and maintain temperature and pressure above the critical point throughout the pipeline route. A suitable pipe-soil heat transfer model during design can mitigate this challenge. However, variations in annual ambient temperatures, ground temperature at pipeline burial depth and soil temperature profile behaviors with seasonal climatic conditions especially during winter and summer periods also affect the heat transfer process between the soil burial medium and the CO2 pipeline. Assuming steady state, this paper investigates the nearfield temperature distribution up to 3m lateral distance away from a buried dense phase CO2 pipeline by numerical simulation with a two-dimensional pipe-soil heat transfer model at a burial depth of 2.3m to pipe center using a finite volume computational code. Results show that thermal parameters such as thermal conductivity and the soil temperature profile influence the heat exchange between pipe walls and porous soil medium. Consequently, this study shows that the near-field temperature distribution and effect of heat around a buried CO2 pipeline diminishes with distance and burial depth further away within the immediate vicinity of the pipeline.

The air-stable, functionalized diphosphine Ph2PCH2CH2P(CH2CH2CO2Me)2 (L1) is the ligand for the Pt(0) complex that efficiently catalyzes the production of L1 from Ph2PCH2CH2PH2 and methyl acrylate....

Carbon‐carbon bond formation is a fundamental transformation in both synthetic chemistry and biosynthesis. Enzymes catalyze such reactions with exquisite selectivity which often cannot be achieved using non‐biological methods but may suffer from an intolerance of high temperature and the presence of organic solvents limiting their applications. Here we report the thermodynamic and kinetic stability of the β‐barrel natural Diels‐Alderase AbyU, which catalyzes formation of the spirotetronate core of the antimicrobial natural product abyssomicin C, with creation of 3 new asymmetric centers. This enzyme is shown to catalyze [4 + 2] cycloadditions at elevated temperature (up to 65 oC), and in the presence of organic solvents (MeOH, CH3CN and DMSO) and the chemical denaturant guanidinium hydrochloride, revealing that AbyU has potential widespread value as a biocatalyst.

The presence of beta‐branches in the structure of polyketides that possess potent biological activity underpins their widespread importance. Kalimantacin is a polyketide antibiotic with selective activity against staphylococci and its biosynthesis involves the unprecedented incorporation of three different and sequential beta‐branching modifications. Here we use purified single and multi‐domain enzyme components of the kalimantacin biosynthetic machinery to address in vitro how the pattern of beta‐branching in kalimantacin is controlled. Robust discrimination of enzyme products required the development of a generalisable assay, taking advantage of direct observe 13C NMR of a single carbon‐13 label incorporated into key biosynthetic mimics combined with favourable dynamic properties of an acyl carrier protein. We report a previously unassigned modular enoyl‐CoA hydratase (mECH) domain and the assembly of enzyme constructs and cascades that are able to generate each specific b‐branch.

We present a new cell membrane modification methodology where the inherent heart tissue homing properties of the infectious bacteria Streptococcus gordonii are transferred to human stem cells., We present a new cell membrane modification methodology where the inherent heart tissue homing properties of the infectious bacteria Streptococcus gordonii are transferred to human stem cells. This is achieved via the rational design of a chimeric protein–polymer surfactant cell membrane binding construct, comprising the cardiac fibronectin (Fn) binding domain of the bacterial adhesin protein CshA fused to a supercharged protein. Significantly, the protein–polymer surfactant hybrid spontaneously inserts into the plasma membrane of stem cells without cytotoxicity, instilling the cells with a high affinity for immobilized fibronectin. Moreover, we show that this cell membrane reengineering approach significantly improves retention and homing of stem cells delivered either intracardially or intravenously to the myocardium in a mouse model.

Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, due to impaired protein and lipid glycosylation. We identified two patients with defective serum transferrin glycosylation and mutations in the MAGT1 gene. These patients present with a phenotype that is mainly characterized by intellectual and developmental disability. MAGT1 has been described to be a subunit of the oligosaccharyltransferase (OST) complex and more specifically of the STT3B complex. However, it was also claimed that MAGT1 is a magnesium (Mg 2+ ) transporter. So far, patients with mutations in MAGT1 were linked to a primary immunodeficiency, characterized by chronic EBV infections attributed to a Mg 2+ homeostasis defect (XMEN). We compared the clinical and cellular phenotype of our two patients to that of an XMEN patient that we recently identified. All three patients have an N-glycosylation defect, as was shown by the study of different substrates, such as GLUT1 and SHBG, demonstrating that the posttranslational glycosylation carried out by the STT3B complex is dysfunctional in all three patients. Moreover, MAGT1 deficiency is associated with an enhanced expression of TUSC3, the homolog protein of MAGT1, pointing toward a compensatory mechanism. Hence, we delineate MAGT1-CDG as a disorder associated with two different clinical phenotypes caused by defects in glycosylation., SCOPUS: ar.j, info:eu-repo/semantics/published

ispartof: ACTA NEUROPATHOLOGICA vol:137 issue:5 pages:855-858 ispartof: location:Germany status: published

Two-dimensional transition metal dichalcogenides (TMDCs) are attracting a broad range of research interest. MoS2 is one of the most common TMDCs. Here, studies on the atomic scale characterization of MoS2 with particular emphasis on Raman spectroscopy and atomic force microscopy are reviewed.

A study into the effects of irradiation temperature on the damage structures that form during proton-irradiation has been carried out on two commercial Zr alloys in order to develop a more mechanistic understanding of the effect of niobium on dislocation loop evolution. The two Zr alloys (Zircaloy-2 and Low-Sn ZIRLO™) were proton irradiated to a damage level of ∼2 dpa at 280 °C, 350 °C and 450 °C. Detailed dislocation analysis was carried out using on-axis bright-field scanning transmission electron microscopy combined with spectral imaging and synchrotron x-ray line profile analysis. The analysis revealed a significant difference in the effect of irradiation temperature on loop size between the two alloys. In the case of the Nb-free Zr-alloy (Zircaloy-2), an increase in irradiation temperature results in a marked increase in a-loop diameter, by a factor of ∼7.5 from 280 to 450 °C, and a stark decrease in the dislocation line density. In contrast, the Nb-containing Zr-alloy (Low-Sn ZIRLO™) showed very little variation of loop size and line density over the same radiation temperature range. The STEM-based spectral imaging revealed irradiation-induced nano-clustering found throughout the matrix in Low-Sn ZIRLO™, which is not present in the case of Zircaloy-2. Therefore, it is proposed that Nb plays a crucial role in the evolution of dislocation loops in Zr through the formation of irradiation precipitation throughout the matrix.

We report a rapid solution-phase strategy to synthesize alloyed PtNi nanoparticles which demonstrate outstanding functionality for the oxygen reduction reaction (ORR). This one-pot co-reduction colloidal synthesis results in a monodisperse population of single-crystal nanoparticles of rhombic dodecahedral morphology, with Pt enriched edges and compositions close to Pt1Ni2. We use nanoscale 3D compositional analysis to reveal for the first time that oleylamine (OAm)-aging of the rhombic dodecahedral Pt1Ni2 particles results in Ni leaching from surface facets, producing aged particles with concave faceting, an exceptionally high surface area and a composition of Pt2Ni1. We show that the modified atomic nanostructures catalytically outperform the original PtNi rhombic dodecahedral particles by more than 2-fold and also yield improved cycling durability. Their functionality for the ORR far exceeds commercially available Pt/C nanoparticle electrocatalysts, both in terms of mass-specific activities (up to a 25-fold increase) and intrinsic area-specific activities (up to a 27-fold increase)., Comment: 14 pages, 4 figures, supplementary information

Thermal analysis of Silicon Carbide (SiC) power semiconductor packages is a crucial design step to ensure highly reliable device performance at elevated temperatures. The square-root-t extrapolation method is widely adopted to approximate the temperature development within the SiC die for short time transients when device temperature measurements cannot be performed. The reduced thermal resistance of the SiC die leads to smaller thermal time constants. Therefore, the approximation of the heat propagation in SiC devices also has to include the die attach. This paper analyzes the thermal behavior of SiC power semiconductor packages by means of comprehensive FEM simulations, allowing to more precisely determine the error of the temperature estimation based on the square-root-t approximation for SiC power devices.

Classical mammalian prions are assemblies of prion protein molecules that are extraordinarily transmissible, with a microgram of protein containing up to 108 lethal doses of infectivity1,2. Unlike most other pathologic and amyloidogenic proteins, prions typically contain glycolipid anchors 3 and abundant asparagine‐linked glycans4‐6. The infectious nature, complexity, and biophysical properties of prions have complicated structural analyses and stymied any prior elucidation of 3D conformation at the polypeptide backbone level7. Here we have determined the structure of the core of a fully infectious, brain‐derived prion by cryo‐electron microscopy with ∼3.1 Å resolution. The purified prions are amyloid fibrils comprised of monomers assembled with parallel in‐register intermolecular beta sheets and connecting chains. Residues ∼95‐227 of each monomer provide one rung of the ordered fibril core, with the glycans and glycolipid anchor projecting from the lateral surfaces of the fibril. The fibril ends, where prion growth occurs, are formed by single monomers in an extended serpentine combination of β‐ arches, a Greek key, and loops that presumably template the refolding of incoming monomers. Our results describe an atomic model to underpin detailed molecular hypotheses of how pathologic prion proteins can propagate as infectious agents, and how such propagation and associated pathogenesis might be impeded.

An ever-increasing array of imaging technologies are being used in the study of complex biological samples, each of which provides complementary, occasionally overlapping information at different length scales and spatial resolutions. It is important to understand the information provided by one technique in the context of the other to achieve a more holistic overview of such complex samples. One way to achieve this is to use annotations from one modality to investigate additional modalities. For microscopy-based techniques, these annotations could be manually generated using digital pathology software or automatically generated by machine learning (including deep learning) methods. Here, we present a generic method for using annotations from one microscopy modality to extract information from complementary modalities. We also present a fast, general, multimodal registration workflow [evaluated on multiple mass spectrometry imaging (MSI) modalities, matrix-assisted laser desorption/ionization, desorption electrospray ionization, and rapid evaporative ionization mass spectrometry] for automatic alignment of complex data sets, demonstrating an order of magnitude speed-up compared to previously published work. To demonstrate the power of the annotation transfer and multimodal registration workflows, we combine MSI, histological staining (such as hematoxylin and eosin), and deep learning (automatic annotation of histology images) to investigate a pancreatic cancer mouse model. Neoplastic pancreatic tissue regions, which were histologically indistinguishable from one another, were observed to be metabolically different. We demonstrate the use of the proposed methods to better understand tumor heterogeneity and the tumor microenvironment by transferring machine learning results freely between the two modalities.

Recently, a disorder caused by the heterozygous de novo c.1267C>T (p.R423*) substitution in SLC37A4 has been described. This causes mislocalization of the glucose-6-phosphate transporter to the Golgi leading to a congenital disorder of glycosylation type II (SLC37A4-CDG). Only one patient has been reported showing liver disease that improved with age and mild dysmorphism. Here we report the second patient with a type II CDG caused by the same heterozygous de novo c.1267C>T (p.R423*) mutation thereby confirming the pathogenicity of this variant and expanding the clinical picture with type 1 diabetes, severe scoliosis, and membranoproliferative glomerulonephritis. Additional clinical and biochemical data provide further insight into the mechanism and prognosis of SLC37A4-CDG. keywords: CDG, G6PT1, glycogen storage disease, glycosylation, hepatopathy, SLC37A4 ispartof: JIMD Reports vol:58 issue:1 pages:122-128 ispartof: location:United States status: published

Prion diseases are progressive, neurodegenerative diseases affecting humans and animals. Also known as the transmissible spongiform encephalopathies, for the hallmark spongiform change seen in the brain, these diseases manifest increased oxidative damage early in disease and changes in antioxidant enzymes in terminal brain tissue. Superoxide dismutase 2 (SOD2) is an antioxidant enzyme that is critical for life. SOD2 knock-out mice can only be kept alive for several weeks post-birth and only with antioxidant therapy. However, this results in the development of a spongiform encephalopathy. Consequently, we hypothesized that reduced levels of SOD2 may accelerate prion disease progression and play a critical role in the formation of spongiform change. Using SOD2 heterozygous knock-out and litter mate wild-type controls, we examined neuronal long-term potentiation, disease duration, pathology, and degree of spongiform change in mice infected with three strains of mouse adapted scrapie. No influence of the reduced SOD2 expression was observed in any parameter measured for any strain. We conclude that changes relating to SOD2 during prion disease are most likely secondary to the disease processes causing toxicity and do not influence the development of spongiform pathology.

The photo-catalytic degradation of a textile azo-dye as Methyl Orange was studied in an innovative unit constituted by a channel over which a layer of titanium dioxide (TiO2) catalyst in anatase form was deposited and activated by UVB irradiation. The degradation kinetics were followed after variation of the chemical, physical, and hydraulic/hydrodynamic parameters of the system. For this purpose, the influence of the TiO2 dosage (g/cm3), dye concentration (mg/L), pH of the solution, flow-rate (L/s), hydraulic load (cm), and irradiation power (W) were evaluated on the degradation rates. It was observed that the maximum dosage of TiO2 was 0.79 g/cm3 while for higher dosage a reduction of homogeneity of the cement conglomerate occurred. The Langmuir&ndash, Hinshelwood (LH) kinetic model was followed up to a dye concentration around 1 mg/L. It was observed that with the increase of the flow rate, an increase of the degradation kinetics was obtained, while the further increase of the flow-rate associated with the modification of the hydraulic load determined a decrease of the kinetic rates. The results also evidenced an increase of the kinetic rates with the increase of the UVB intensity. A final comparison with other dyes such as Methyl Red and Methylene Blue was carried out in consideration of the pH of the solution, which sensibly affected the removal efficiencies.

This paper proposes an innovative bioaugmentation approach for the remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soils, based on a novel habitat-based strategy. This approach was tested using two inocula (i-24 and i-96) previously enriched through an anaerobic digestion process on wheat straw. It relies on the application of allochthonous microorganisms characterized by specific functional roles obtained by mimicking a natural hydrolytic environment such as the rumen. The inocula efficiency was tested in presence of naphthalene alone, benzo[a]pyrene alone, and a mix of both of them. In single-contamination tests, i-24 inoculum showed the highest biodegradation rates (84.7% for naphthalene and 51.7% for benzo[a]pyrene). These values were almost 1.2 times higher than those obtained for both contaminants with i-96 inoculum and in the control test in presence of naphthalene alone, while they were 3 times higher compared to the control test in presence of benzo[a]pyrene alone. In mixed-contamination tests, i-96 inoculum showed final biodegradation efficiencies for naphthalene and benzo[a]pyrene between 1.1 and 1.5 higher than i-24 inoculum or autochthonous biomass. Total microbial abundances increased in the bioaugmented tests in line with the PAH degradation. The microbial community structure showed the highest diversity at the end of the experiment in almost all cases. Values of the Firmicutes active fraction up to 7 times lower were observed in the i-24 bioaugmented tests compared to i-96 and control tests. This study highlights a successful bioaugmentation strategy with biological components that can be reused in multiple processes supporting an integrated and environmentally sustainable bioremediation system.

In the present work the use of a sequence of two solar photocatalytic processes was investigated for the removal of copper, iron, zinc and ethylenediaminedisuccinic acid (EDDS), used as chelating agent, from real soil washing effluents. Removal efficiencies of 93.5% (copper), 99.6% (iron), 99.4% (zinc), 97.2% (EDDS) and 80.7% (TOC) were achieved through outdoor solar photocatalytic treatments using parabolic trough collectors and carried out in Naples (Italy, N 40°50′, E 14°12′) in the period June–July 2015. These removal efficiencies were achieved for an incident UVA solar energy per unit volume (Qj,n) of 580 kJ·L−1, calculated by taking into account the irradiated surface area of the photoreactor estimated in the present work (9.79 × 10−2 m2) and the solar irradiance measurements collected during the experiments. The results suggest that the two-step solar process adopted can be proposed as a useful solution to the problem of heavy metals and chelating organic agents removals from soil washing. The ecotoxicological assessment, using different living organisms (Daphnia magna, Vibrio fischeri, Pseudokirchneriella subcapitata, Lepidium sativum and Caenorhabditis elegans), showed a noticeable decrease of the ecotoxicity of the soil washing effluents after the two-step photocatalytic process.

This study proposes a comparison of different ex situ technologies aimed at the removal of polycyclic aromatic hydrocarbons from marine sediments in terms of performances, costs and energy balance. In accordance with the principles of water-energy nexus, anaerobic bioremediation, soil washing and thermal desorption were investigated under low liquid phase and temperature conditions using phenanthrene (PHE) as model compound. After 42 days of anaerobic bioremediation, the highest PHE biodegradation of 68 and 64% was observed under denitrifying and methanogenic conditions, respectively, accompanied by N2 and CH4 production and volatile fatty acid accumulation. During soil washing, more than 97% of PHE was removed after 60 min using a solid-to-liquid ratio of 1:3. Along the same treatment time, low-temperature thermal desorption (LTTD) allowed a PHE removal of 88% at 200 °C. The economic analysis indicated that LTTD resulted in a higher cost (i.e. 1782 € m−3) than bioremediation and soil washing (228 and 371 € m−3, respectively). The energy balance also suggested that bioremediation and soil washing are more sustainable technologies as a lower required energy (i.e. 16 and 14 kWh m−3, respectively) than LTTD (i.e. 417 kWh m−3) is needed.

The accumulation of trace metals in soils is one of the main drawbacks when reclaimed waters are used as irrigation sources in agriculture. Such secondary water sources often also contain high levels of salinity and in detail sodium. How the presence of sodium influences the fate of trace metals in the environment is still obscure and of primary importance in defining sustainable agricultural management guidelines. Standard OECD soil columns were subjected to 25 days irrigation with aqueous solutions containing trace concentrations of Cd, Cu, Ni and Zn at increasing sodium content. The dataset is supplementary to the data presented and discussed in “Effect of sodium concentration on mobilization and fate of trace metals in standard OECD soil” [1]. The leachates collected from the columns were deeply characterized in terms of concentration of metals, organic (monitored through UV-VIS, 3DEEM, E4/E6 ratio, COD) and inorganic matter (monitored as Al concentration). The dataset was analyzed by PCA and “Paerson” correlation coefficient. Keywords: Colloidal mobilization, Trace metals, Reclaimed wastewater, Soil pollution, Humic substances

Cerium (Ce, CeCl3) and Erbium (Er, ErCl3) are increasingly used in many electronic devices facilitating the alteration of their biogeochemical cycles (e.g. e-waste). Previous surveys stated that their environmental concentrations due to natural or anthropogenic events can reach up to 161 μg/L in ore mine effluent for Ce with a mean water concentration of 0.79 μg/L, and 11.9 μg/L for Er in ore mine effluents with a mean water concentration of 0.004 μg/L. Their potential effects onto aquatic organisms are still relatively unexplored. In this study, long-term multigenerational effects on Daphnia magna were assessed using various exposure times (3, 7, 14, and 21 days) in three generations (F0, F1 and F2). Each generation was exposed to environmental concentrations of Ce and Er (0.54 and 0.43 μg/L, respectively – mean values) and effects included organisms' size, parental reproduction, and survival, determination of reactive oxygen species (ROS), enzymatic activity (superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST)), gene expression of ATP-binding cassette (ABC) transporter, and uptake. Results evidenced that chronic multi-generational exposure of daphnids to Ce and Er reduced survival, growth and reproduction, decreasing ROS, SOD and CAT from F0 to F2. Ce reduced the number of generated offsprings after each generation, while Er delayed the time of offsprings emergence, but not their number. ROS, SOD, CAT and GST evidenced that Er is slightly more toxic than Ce. Up- and downregulation of genes was limited, but Ce and Er activated the ABC transporters. Uptake of Ce and Er decreased through exposure time and generations.

This paper analyzes the effect of caesium (Cs) concentration on seed germination, seedling growth, root uptake, and leaf uptake of Lactuca sativa to understand the potential transfer of the metal from contaminated soil to humans through the food chain. The results of germination experiments show that seed germination and seedling growth strongly depend on increasing Cs concentration, with a decrease in the number of germinated seeds compared to the control up to 13.6% and a reduction in seedling growth up to 10.3% at the highest Cs tested concentration (15 mM). Uptake experiments indicate a low transfer of Cs from soil to leaves and roots of the plants, ranging between 0.06% and 2.2%. The transfer is found to be a not-monotone function of soil potassium (K) content, with highest values corresponding to 1–2 mM K2SO4. Increasing concentrations of K lead to lower translocation of Cs from roots to leaves. Values above the average amount applied (20 and 40 mM K2SO4) almost stop the translocation, suggesting the use of a high amount of K2SO4 protects the food chain from Cs contamination.

The inadequate management of asbestos-cement products (ACP) and/or wastes (ACW) generates hazardous airborne dusts. For this reason, the EU is promoting the removal of ACP from utilities, public and private buildings and is looking for innovative ACW treatments alternative to the landfilling. The simultaneous treatment of ACW and orange pulp or cheese whey was attempted with a mesophilic dark fermentation (DF) process followed by a 12 h hydrothermal (HT) treatment carried out with the addition of lactic or oxalic acid at 100 °C and ambient pressure. The DF of orange pulp or cheese whey in the presence of 5 g L−1 ACW lasted 171 h and led to the production of 4 L H 2 and 5 L H 2 per litre of solution, respectively. During the DF, the dissolution of the ACW matrix was almost completed, and the partial collapse of the asbestos fibres was observed. Both the organic acids that were added during the HT tests at a concentration ≥2.5 g L−1 completely destroyed the asbestos fibres. However, when 1.25 g L−1 lactic or oxalic acid was added before the HT tests, few fibre fragments were found, and their chemical composition differed from that of chrysotile.

In this paper, the treatment of asbestos-cement waste (ACW) has been attempted by a dark fermentation (DF) pre-treatment followed by hydrothermal and anaerobic digestion (AD) treatments. During DF, glucose, employed as a biodegradable substrate, was mainly converted to H-2-rich biogas and organic acids (OAs). The latter caused the dissolution of the cement matrix and the partial structural collapse of chrysotile (white asbestos). To complete the chrysotile degradation, hydrothermal treatment of the DF effluents was performed under varying operating conditions (temperature, acid type, and load). After the addition of 5.0 g/L sulfuric acid, a temperature decrease, from 80 degrees C to 40 degrees C, slowed down the treatment. Similarly, at 100 degrees C, a decrease of sulfuric, lactic or malic acid load from 5.0 g/L to 1.0 g/L slowed down the process, regardless of acid type. The acid type did not affect the hydrothermal treatment but influenced the AD of the hydrothermal effluents. Indeed, when malic acid was used, the AD of the hydrothermally treated effluents resulted in the highest production of methane. At the end of the AD treatment, some magnesium ions derived from ACW dissolution participated in the crystallization of struvite, an ecofriendly phosphorous-based fertilizer.