Comparative Analysis of the Inhibitory Mechanism of Aß1-42 Aggregation by Diruthenium Complexes.

There is a growing interest in the search for metal-based therapeutics for protein misfolding disorders such as Alzheimer's disease (AD). A novel and largely unexplored class of metallodrugs is constituted by paddlewheel diruthenium complexes, which exhibit unusual water solubility and stability and unique coordination modes to proteins. Here, we investigate the ability of the complexes [Ru2Cl(DPhF)(O2CCH3)3]·H2O (1), [Ru2Cl(DPhF)2(O2CCH3)2]·H2O (2), and K2[Ru2(DPhF)(CO3)3]·3H2O (3) (DPhF- = N,N'-diphenylformamidinate) to interfere with the amyloid aggregation of the Aß1-42 peptide. These compounds differ in charge and steric hindrance due to the coordination of a different number of bulky ligands. The mechanisms of action of the three complexes were studied by employing a plethora of physicochemical and biophysical techniques as well as cellular assays. All these studies converge on different mechanisms of inhibition of amyloid fibrillation: complexes 1 and 2 show a clear inhibitory effect due to an exchange ligand process in the Ru2 unit aided by aromatic interactions. Complex 3 shows no inhibition of aggregation, probably due to its negative charge in solution. This study demonstrates that slight variations in the ligands surrounding the bimetallic core can modulate the amyloid aggregation inhibition and supports the use of paddlewheel diruthenium complexes as promising therapeutics for Alzheimer's disease.

A Diruthenium Metallodrug as a Potent Inhibitor of Amyloid-ß Aggregation: Synergism of Mechanisms of Action.

The physical and chemical properties of paddlewheel diruthenium compounds are highly dependent on the nature of the ligands surrounding the bimetallic core. Herein, we compare the ability of two diruthenium compounds, [Ru2Cl(D-p-FPhF)(O2CCH3)3]·H2O (1) (D-p-FPhF- = N,N'-bis(4-fluorophenyl)formamidinate) and K3[Ru2(O2CO)4]·3H2O (2), to act as inhibitors of amyloid aggregation of the Aß1-42 peptide and its peculiar fragments, Aß1-16 and Aß21-40. A wide range of biophysical techniques has been used to determine the inhibition capacity against aggregation and the possible mechanism of action of these compounds (Thioflavin T fluorescence and autofluorescence assays, UV-vis absorption spectroscopy, circular dichroism, nuclear magnetic resonance, mass spectrometry, and electron scanning microscopy). Data show that the most effective inhibitory effect is shown for compound 1. This compound inhibits fiber formation and completely abolishes the cytotoxicity of Aß1-42. The antiaggregatory capacity of this complex can be explained by a binding mechanism of the dimetallic units to the peptide chain along with π-π interactions between the formamidinate ligand and the aromatic side chains. The results suggest the potential use of paddlewheel diruthenium complexes as neurodrugs and confirm the importance of the steric and charge effects on the properties of diruthenium compounds.

Effect of Equatorial Ligand Substitution on the Reactivity with Proteins of Paddlewheel Diruthenium Complexes: Structural Studies.

The paddlewheel [Ru2Cl(O2CCH3)4] complex was previously reported to react with the model protein hen egg white lysozyme (HEWL), forming adducts with two diruthenium moieties bound to Asp101 and Asp119 side chains upon the release of one acetate. To study the effect of the equatorial ligands on the reactivity with proteins of diruthenium compounds, X-ray structures of the adducts formed when HEWL reacts with [Ru2Cl(D-p-FPhF)(O2CCH3)3] [D-p-FPhF = N,N'-bis(4-fluorophenyl)formamidinate] under different conditions were solved. [Ru2Cl(D-p-FPhF)(O2CCH3)3] is bonded through their equatorial positions to the Asp side chains. Protein binding occurs cis or trans to D-p-FPhF. Lys or Arg side chains or even main-chain carbonyl groups can coordinate to the diruthenium core at the axial site. Data help to understand the reactivity of paddlewheel diruthenium complexes with proteins, providing useful information for the design of new artificial diruthenium-containing metalloenzymes with potential applications in the fields of catalysis, biomedicine, and biotechnology.

Effective bioremediation of soil from the Burgan oil field (Kuwait) using compost: A comprehensive hydrocarbon and DNA fingerprinting study.

An innovative combination of metagenomic profiling of microbial communities and GC-MS & Pyrolysis-GC-MS fingerprinting methods were used to assess the biodegradation of contaminated soil from the Burgan oil field in Kuwait. The soil was treated with (sludge) compost in microcosms to evaluate the feasibility of this material for bioremediation purposes. The most favourable trial showed a > 80% decrease in TPH, thereby indicating strong potential for full-scale application using a cost-effective technology and thus in line with the principles of the circular economy. The microbial study showed that compost addition enhanced the organic matter and nutrient content of the soil. However, the microorganisms in the compost did not seem to play a relevant role in bioremediation, meaning that compost amendments serve as a biostimulation rather than a bioaugmentation approach. The chemical study of the distinct oil fractions revealed rapidly biodegraded compounds (alkanes, alkyl-aromatics, etc.) and others that were much more refractory (hopanes, benzohopanes, etc.). Of note, although heavy fractions are usually considered recalcitrant to biodegradation, we observed incipient degradation of the asphaltene fraction by means of double-shot thermodesorption and pyrolysis. Finally, chemical fingerprinting also revealed that the treated soil contained some of the compounds found in the compost, such as coprostanol, cholesterol, and plant sterols. This observation would support the use of these compounds as proxies to monitor the effects of compost and to adjust dosages in real-scale bioremediation treatments.

Activating Killer-Cell Immunoglobulin-Like Receptors Are Associated With the Severity of Coronavirus Disease 2019.

BACKGROUND: Etiopathogenesis of the clinical variability of the coronavirus disease 2019 (COVID-19) remains mostly unknown. In this study, we investigate the role of killer cell immunoglobulin-like receptor (KIR)/human leukocyte antigen class-I (HLA-I) interactions in the susceptibility and severity of COVID-19. METHODS: We performed KIR and HLA-I genotyping and natural killer cell (NKc) receptors immunophenotyping in 201 symptomatic patients and 210 noninfected controls. RESULTS: The NKcs with a distinctive immunophenotype, suggestive of recent activation (KIR2DS4low CD16low CD226low CD56high TIGIThigh NKG2Ahigh), expanded in patients with severe COVID-19. This was associated with a higher frequency of the functional A-telomeric activating KIR2DS4 in severe versus mild and/or moderate patients and controls (83.7%, 55.7% and 36.2%, P < 7.7 × 10-9). In patients with mild and/or moderate infection, HLA-B*15:01 was associated with higher frequencies of activating B-telomeric KIR3DS1 compared with patients with other HLA-B*15 subtypes and noninfected controls (90.9%, 42.9%, and 47.3%; P < .002; Pc = 0.022). This strongly suggests that HLA-B*15:01 specifically presenting severe acute respiratory syndrome coronavirus 2 peptides could form a neoligand interacting with KIR3DS1. Likewise, a putative neoligand for KIR2DS4 could arise from other HLA-I molecules presenting severe acute respiratory syndrome coronavirus 2 peptides expressed on infected an/or activated lung antigen-presenting cells. CONCLUSIONS: Our results support a crucial role of NKcs in the clinical variability of COVID-19 with specific KIR/ligand interactions associated with disease severity.

Design and catalytic studies of structural and functional models of the catechol oxidase enzyme.

The catechol oxidase activity of three copper/bicompartmental salen derivatives has been studied. One mononuclear, [CuL] (1), one homometallic, [Cu2L(NO3)2] (2), and one heterometallic, [CuMnL(NO3)2] (3) complexes were obtained using the ligand H2L = N,N'-bis(3-methoxysalicylidene)-1,3-propanediamine through different synthetic methods (electrochemical, chemical and solid state reaction). The structural data indicate that the metal ion disposition models the active site of type-3 copper enzymes, such as catechol oxidase. In this way, their ability to act as functional models of the enzyme has been spectrophotometrically determined by monitorization of the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butyl-o-benzoquinone (3,5-DTBQ). All the complexes show significant catalytic activity with ratio constants (kobs) lying in the range (223-294) × 10-4 min-1. A thorough kinetic study was carried out for complexes 2 and 3, since they show structural similarities with the catechol oxidase enzyme. The greatest catalytic activity was found for the homonuclear dicopper compound (2) with a turnover value (kcat) of (3.89 ± 0.05) × 106 h-1, which it is the higher reported to date, comparable to the enzyme itself (8.25 × 106 h-1).

Wickerhamiella verensis f.a. sp. nov., a novel yeast species isolated from subsoil groundwater contaminated with hydrocarbons and from a human infection.

Yeast strains belonging to a novel anamorphic yeast species were isolated from subsoil groundwater contaminated with hydrocarbons in a metal working factory located in northern Spain, and from a human infection in the USA. Comparison of ITS sequences between the isolates revealed 0.2 % divergence between the Spanish isolates and 0.46 % divergence between those and the USA isolate. Phylogenetic analysis based on the D1/D2 domains of the LSU rRNA gene showed that these isolates belong to the Wickerhamiella clade with W. sorbophila and W. infanticola as their closest relatives. Sequence divergence between the new isolates and W. sorbophila and W. infanticola was 1.97 and 1.79 %, respectively. The isolates in the novel species are not fermentative and pseudohyphae were not produced. Sexual reproduction was not observed for individual isolates or in mixtures of isolates. Conjugation between the isolates in the novel species and close relatives W. sorbophila and W. infanticola was not observed. These data support the proposal of Wickerhamiella verensis as a novel species, with CECT 12028T as the holotype.

Expected and Unexpected Imaging Findings after 90Y Transarterial Radioembolization for Liver Tumors.

Transarterial radioembolization (TARE), also called radioembolization or selective internal radiation therapy, is an interventional radiology technique used to treat primary liver tumors and liver metastases. The aim of this therapy is to deliver tumoricidal doses of radiation to liver tumors while selecting a safe radiation dose limit for nontumoral liver and lung tissue. Hence, correct treatment planning is essential to obtaining good results. However, this treatment invariably results in some degree of irradiation of normal liver parenchyma, inducing different radiologic findings that may affect follow-up image interpretation. When evaluating treatment response, the treated area size, tumor necrosis, devascularization, and changes seen at functional MRI must be taken into account. Unlike with other interventional procedures, with TARE, it can take several months for the tumor response to become evident. Ideally, responding lesions will show reduced size and decreased enhancement 3-6 months after treatment. In addition, during follow-up, there are many imaging findings related to the procedure itself (eg, peritumoral edema, inflammation, ring enhancement, hepatic fibrosis, and capsular retraction) that can make image interpretation and response evaluation difficult. Possible complications, either hepatic or extrahepatic, also can occur and include biliary injuries, hepatic abscess, radioembolization-induced liver disease, and radiation pneumonitis or dermatitis. A complete understanding of these possible posttreatment changes is essential for correct radiologic interpretations during the follow-up of patients who have undergone TARE. ©RSNA, 2019.

Use of Endophytic and Rhizosphere Bacteria To Improve Phytoremediation of Arsenic-Contaminated Industrial Soils by Autochthonous Betula celtiberica.

The aim of this study was to investigate the potential of indigenous arsenic-tolerant bacteria to enhance arsenic phytoremediation by the autochthonous pseudometallophyte Betula celtiberica The first goal was to perform an initial analysis of the entire rhizosphere and endophytic bacterial communities of the above-named accumulator plant, including the cultivable bacterial species. B. celtiberica's microbiome was dominated by taxa related to Flavobacteriales, Burkholderiales, and Pseudomonadales, especially the Pseudomonas and Flavobacterium genera. A total of 54 cultivable rhizobacteria and 41 root endophytes, mainly affiliated with the phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria, were isolated and characterized with respect to several potentially useful features for metal plant accumulation, such as the ability to promote plant growth, metal chelation, and/or mitigation of heavy-metal stress. Seven bacterial isolates were further selected and tested for in vitro accumulation of arsenic in plants; four of them were finally assayed in field-scale bioaugmentation experiments. The exposure to arsenic in vitro caused an increase in the total nonprotein thiol compound content in roots, suggesting a detoxification mechanism through phytochelatin complexation. In the contaminated field, the siderophore and indole-3-acetic acid producers of the endophytic bacterial consortium enhanced arsenic accumulation in the leaves and roots of Betula celtiberica, whereas the rhizosphere isolate Ensifer adhaerens strain 91R mainly promoted plant growth. Field experimentation showed that additional factors, such as soil arsenic content and pH, influenced arsenic uptake in the plant, attesting to the relevance of field conditions in the success of phytoextraction strategies.IMPORTANCE Microorganisms and plants have developed several ways of dealing with arsenic, allowing them to resist and metabolize this metalloid. These properties form the basis of phytoremediation treatments and the understanding that the interactions of plants with soil bacteria are crucial for the optimization of arsenic uptake. To address this in our work, we initially performed a microbiome analysis of the autochthonous Betula celtiberica plants growing in arsenic-contaminated soils, including endosphere and rhizosphere bacterial communities. We then proceeded to isolate and characterize the cultivable bacteria that were potentially better suited to enhance phytoextraction efficiency. Eventually, we went to the field application stage. Our results corroborated the idea that recovery of pseudometallophyte-associated bacteria adapted to a large historically contaminated site and their use in bioaugmentation technologies are affordable experimental approaches and potentially very useful for implementing effective phytoremediation strategies with plants and their indigenous bacteria.

Radiological anatomy assessment of the fissura pterygomaxillaris for a surgical approach to ganglion pterygopalatinum.

The ganglion pterygopalatinum has become a therapeutic target to treat various pain syndromes in recent years. It is located in the fossa pterygopalatina, and the fissura pterygomaxillaris is the main access to surgically approach this structure. Recently, the neuromodulation of the ganglion pterygopalatinum by microstimulator implantation has become the first therapeutic line in refractory cluster headache treatment. This invasive technique is performed transorally through the fissura pterygomaxillaris, and is limited by the size of the implantation device, which requires an opening of at least 2 mm. Therefore, extensive knowledge about the anatomy of the fissura pterygomaxillaris prior to surgery is necessary to predict the success of both the approach and intervention. Likewise, establishing a morphological typology of the different fissura pterygomaxillaris variations would be a valuable predictive tool in the clinical practice. In this work, an anatomical analysis was performed of the morphological characteristics of the 242 fissurae pterygomaxillares, which corresponded to 121 adult patients, 58 males and 63 females, aged between 18 and 87 years. For each subject, right and left fissures were studied with radiological computed tomography images. Aperture fissura pterygomaxillaris measurements were taken in an upper (Measure A), middle (Measure B) and lower craneo-caudal third (Measure C). Intra-subject differences were studied between the measurements taken of each patient's right and left fissures, and the inter-subject measures in which fissures were compared according to patients' age and gender. The obtained results showed no significant differences between each patient's right and left fissures in any three measurements taken. Intra-subject differences were not significant for gender or age. No statistically significant differences were found for the inter-subject measures between the measures of fissures according to patients' age. However, our data revealed that males' fissurae pterygomaxillares were significantly larger than those of females in all three measures. Having analysed fissures, a typological classification was made according to the morphological patterns found. A 2-mm limiting measure was considered, and Measures A, B and C of each fissure were classified depending on whether they had a value above or equal to 2 mm, or below 2 mm. With this classification criterion, four fissurae pterygomaxillares types were obtained. Type I and II fissure values (with a higher prevalence) were equal to or were greater than 2 mm in all three measures, or in two measures. Type III fissure values were only greater than or equal to 2 mm in Measure A, whereas all the Type IV fissure values were below 2 mm. Future studies are necessary to correlate the fissure types successfully proposed in the surgical ganglion pterygopalatinum approach.

Context-specific metabolic network reconstruction of a naphthalene-degrading bacterial community guided by metaproteomic data.

MOTIVATION: With the advent of meta-'omics' data, the use of metabolic networks for the functional analysis of microbial communities became possible. However, while network-based methods are widely developed for single organisms, their application to bacterial communities is currently limited. RESULTS: Herein, we provide a novel, context-specific reconstruction procedure based on metaproteomic and taxonomic data. Without previous knowledge of a high-quality, genome-scale metabolic networks for each different member in a bacterial community, we propose a meta-network approach, where the expression levels and taxonomic assignments of proteins are used as the most relevant clues for inferring an active set of reactions. Our approach was applied to draft the context-specific metabolic networks of two different naphthalene-enriched communities derived from an anthropogenically influenced, polyaromatic hydrocarbon contaminated soil, with (CN2) or without (CN1) bio-stimulation. We were able to capture the overall functional differences between the two conditions at the metabolic level and predict an important activity for the fluorobenzoate degradation pathway in CN1 and for geraniol metabolism in CN2. Experimental validation was conducted, and good agreement with our computational predictions was observed. We also hypothesize different pathway organizations at the organismal level, which is relevant to disentangle the role of each member in the communities. The approach presented here can be easily transferred to the analysis of genomic, transcriptomic and metabolomic data.

SrMnO3 Thermochromic Behavior Governed by Size-Dependent Structural Distortions.

The influence of particle size in both the structure and thermochromic behavior of 4H-SrMnO3 related perovskite is described. Microsized SrMnO3 suffers a structural transition from hexagonal (P63/mmc) to orthorhombic (C2221) symmetry at temperature close to 340 K. The orthorhombic distortion is due to the tilting of the corner-sharing Mn2O9 units building the 4H structural type. When temperature decreases, the distortion becomes sharper reaching its maximal degree at ∼125 K. These structural changes promote the modification of the electronic structure of orthorhombic SrMnO3 phase originating the observed color change. nano-SrMnO3 adopts the ideal 4H hexagonal structure at room temperature, the orthorhombic distortion being only detected at temperature below 170 K. A decrease in the orthorhombic distortion degree, compared to that observed in the microsample, may be the reason why a color change is not observed at low temperature (77 K).

The significance of metabolic alkalosis on acute decompensated heart failure: the ALCALOTIC study.

AIMS: To determine the prevalence and the impact on prognosis of metabolic alkalosis (MA) in patients admitted for acute heart failure (AHF). METHODS AND RESULTS: The ALCALOTIC is a multicenter, observational cohort study that prospectively included patients admitted for AHF. Patients were classified into four groups according to their acid-base status on admission: acidosis, MA, respiratory alkalosis, and normal pH (reference group for comparison). Primary endpoint was all-cause in-hospital mortality, and secondary endpoints included 30/90-day all-cause mortality, all-cause readmission, and readmission for HF. Associations between endpoints and acid-base alterations were estimated in a multivariate Cox regression model including sex, age, comorbidities, and Barthel index and expressed as hazard ratio (HR) with 95% confidence interval (95% CI). Six hundred sixty-five patients were included (84 years and 57% women), and 40% had acid-base alterations on admission: 188 (28%) acidosis and 78 (12%) alkalosis. The prevalence (95% CI) of MA was 9% (6.8-11.2%). Patients with MA were more women; had fewer comorbidities, better renal function, and higher left ventricle ejection fraction values; and received more treatment with oral acetazolamide during hospitalization and at discharge. MA was not associated with a higher risk of in-hospital mortality and 30/90-day all-cause mortality or readmissions but was associated with a significant increase in readmissions for HF at 30 and 90 days (adjusted HR [95% CI] 3.294 [1.397-7.767], p = 0.006 and 2.314 [1.075-4.978], p = 0.032). CONCLUSION: The prevalence of MA in patients admitted for AHF was 9%, and its presence was associated with more readmissions for HF but not with all-cause mortality.

Thick shells and medially wedged posts increase foot orthoses medial longitudinal arch stiffness: an experimental study.

BACKGROUND: Foot orthoses (FOs) are commonly prescribed devices to attenuate biomechanical deficits and improve physical function in patients with musculoskeletal disorders. It is postulated that FOs provide their effects through the production of reaction forces at the foot-FOs interface. An important parameter to provide these reaction forces is their medial arch stiffness. Preliminary results suggest that adding extrinsic additions to FOs (e.g., rearfoot posts) increases their medial arch stiffness. A better understanding of how FOs medial arch stiffness can be modulated by changing structural factors is necessary to better customise FOs for patients. The objectives of this study were to compare FOs stiffness and force required to lower the FOs medial arch in three thicknesses and two models (with and without medially wedged forefoot-rearfoot posts). METHODS: Two models of FOs, 3D printed in Polynylon-11, were used: (1) without extrinsic additions (mFO), and (2) with forefoot-rearfoot posts and a 6o medial wedge (FO6MW). For each model, three thicknesses (2.6 mm, 3.0 mm, and 3.4 mm) were manufactured. FOs were fixed to a compression plate and vertically loaded over the medial arch at a rate of 10 mm/minute. Two-way ANOVAs and Tukey post-hoc tests with Bonferroni corrections were used to compare medial arch stiffness and force required to lower the arch across conditions. RESULTS: Regardless of the differing shell thicknesses, the overall stiffness was 3.4 times greater for FO6MW compared to mFO (p < 0.001). FOs with 3.4 mm and 3.0 mm thicknesses displayed 1.3- and 1.1- times greater stiffness than FOs with a thickness of 2.6 mm. FOs with a thickness of 3.4 mm also exhibited 1.1 times greater stiffness than FOs with a thickness of 3.0 mm. Overall, the force to lower the medial arch was up to 3.3 times greater for FO6MW than mFO and thicker FOs required greater force (p < 0.001). CONCLUSIONS: An increased medial longitudinal arch stiffness is seen in FOs following the addition of 6o medially inclined forefoot-rearfoot posts, and when the shell is thicker. Overall, adding forefoot-rearfoot posts to FOs is significantly more efficient than increasing shell thickness to enhance these variables should that be the therapeutic aim.

The microbiome of a brownfield highly polluted with mercury and arsenic.

Abandoned brownfields represent a challenge for their recovery. To apply sustainable remediation technologies, such as bioremediation or phytoremediation, indigenous microorganisms are essential agents since they are adapted to the ecology of the soil. Better understanding of microbial communities inhabiting those soils, identification of microorganisms that drive detoxification process and recognising their needs and interactions will significantly improve the outcome of the remediation. With this in mind we have carried out a detailed metagenomic analysis to explore the taxonomic and functional diversity of the prokaryotic and eukaryotic microbial communities in soils, several mineralogically distinct types of pyrometallurgic waste, and groundwater sediments of a former mercury mining and metallurgy site which harbour very high levels of arsenic and mercury pollution. Prokaryotic and eukaryotic communities were identified, which turned out to be more diverse in the surrounding contaminated soils compared to the pyrometallurgic waste. The highest diversity loss was observed in two environments most contaminated with mercury and arsenic (stupp, a solid mercury condenser residue and arsenic-rich soot from arsenic condensers). Interestingly, microbial communities in the stupp were dominated by an overwhelming majority of archaea of the phylum Crenarchaeota, while Ascomycota and Basidiomycota fungi comprised the fungal communities of both stump and soot, results that show the impressive ability of these previously unreported microorganisms to colonize these extreme brownfield environments. Functional predictions for mercury and arsenic resistance/detoxification genes show their increase in environments with higher levels of pollution. Our work establishes the bases to design sustainable remediation methods and, equally important, to study in depth the genetic and functional mechanisms that enable the subsistence of microbial populations in these extremely selective environments.

Steric hindrance and charge influence on the cytotoxic activity and protein binding properties of diruthenium complexes.

Paddlewheel diruthenium complexes are being used as metal-based drugs. It has been proposed that their charge and steric properties determine their selectivity towards proteins. Here, we explore these parameters using the first water-soluble diruthenium complex bearing two formamidinate ligands, [Ru2Cl(DPhF)2(O2CCH3)2], and two derivatives, [Ru2Cl(DPhF)(O2CCH3)3] and K2[Ru2(DPhF)(CO3)3] (DPhF- = N,N'-diphenylformamidinate), with one formamidinate. Their protein binding properties have been assessed employing hen egg white lysozyme (HEWL). The results confirm the relationship between the type of interaction (coordinate/non-coordinate bonds) and the charge of diruthenium complexes. The crystallization medium is also a key factor. In all cases, diruthenium species maintain the M-M bond and produce stable adducts. The antiproliferative properties of these diruthenium complexes have been evaluated on an eukaryotic cell-based model. Our data show a correlation between the number of the formamidinate ligands and the anticancer activity of the diruthenium derivatives against human epithelial carcinoma cells. Increased cytotoxicity may be related to increased steric hindrance and Ru25+ core electronic density. However, the effect of increasing the lipophilicity of diruthenium species by introducing a second N,N'-diphenylformamidinate must be also considered. This work illustrates a systematic approach to shed light on the relevant properties of diruthenium compounds to design metal-based metallodrugs and diruthenium metalloenzymes.

Metagenomic Mining for Esterases in the Microbial Community of Los Rueldos Acid Mine Drainage Formation.

Acid mine drainage (AMD) systems are extremely acidic and are metal-rich formations inhabited by relatively low-complexity communities of acidophiles whose enzymes remain mostly uncharacterized. Indeed, enzymes from only a few AMD sites have been studied. The low number of available cultured representatives and genome sequences of acidophiles inhabiting AMDs makes it difficult to assess the potential of these environments for enzyme bioprospecting. In this study, using naïve and in silico metagenomic approaches, we retrieved 16 esterases from the α/ß-hydrolase fold superfamily with the closest match from uncultured acidophilic Acidobacteria, Actinobacteria (Acidithrix, Acidimicrobium, and Ferrimicrobium), Acidiphilium, and other Proteobacteria inhabiting the Los Rueldos site, which is a unique AMD formation in northwestern Spain with a pH of ∼2. Within this set, only two polypeptides showed high homology (99.4%), while for the rest, the pairwise identities ranged between 4 and 44.9%, suggesting that the diversity of active polypeptides was dominated not by a particular type of protein or highly similar clusters of proteins, but by diverse non-redundant sequences. The enzymes exhibited amino acid sequence identities ranging from 39 to 99% relative to homologous proteins in public databases, including those from other AMDs, thus indicating the potential novelty of proteins associated with a specialized acidophilic community. Ten of the 16 hydrolases were successfully expressed in Escherichia coli. The pH for optimal activity ranged from 7.0 to 9.0, with the enzymes retaining 33-68% of their activities at pH 5.5, which was consistent with the relative frequencies of acid residues (from 54 to 67%). The enzymes were the most active at 30-65°C, retaining 20-61% of their activity under the thermal conditions characterizing Los Rueldos (13.8 ± 0.6°C). The analysis of the substrate specificity revealed the capacity of six hydrolases to efficiently degrade (up to 1,652 ± 75 U/g at pH 8.0 and 30°C) acrylic- and terephthalic-like [including bis(2-hydroxyethyl)-terephthalate, BHET] esters, and these enzymes could potentially be of use for developing plastic degradation strategies yet to be explored. Our assessment uncovers the novelty and potential biotechnological interest of enzymes present in the microbial populations that inhibit the Los Rueldos AMD system.

Bacterial inoculant-assisted phytoremediation affects trace element uptake and metabolite content in Salix atrocinerea.

Natural plant-associated microorganisms are of critical importance to plant growth and survival in field conditions under toxic concentrations of trace elements (TE) and these plant-microbial processes can be harnessed to enhance phytoremediation. The total bacterial diversity from grey willow (Salix atrocinerea) on a brownfield heavily-polluted with lead (Pb) and arsenic (As) was studied through pyrosequencing. Culturable bacteria were isolated and in vitro tested for plant growth-promotion (PGP) traits, arsenic (As) tolerance and impact on As speciation. Two of the most promising bacterial strains - the root endophyte Pantoea sp. AV62 and the rhizospheric strain Rhodococcus erythropolis AV96 - were inoculated in field to S. atrocinerea. This bioaugmentation resulted in higher As and Pb concentrations in both, roots and leaves of bacterial-inoculated plants as compared to non-inoculated plants. In consequence, bacterial bioaugmentation also affected parameters related to plant growth, oxidative stress, the levels of phytochelatins and phenylpropanoids, together with the differential expression of genes related to these tolerance mechanisms to TE in leaves. This study extends our understanding about plant-bacterial interactions and provides a solid basis for further bioaugmentation studies aiming to improve TE phytoremediation efficiency and predictability in the field.

Dolutegravir plus rilpivirine: benefits beyond viral suppression: DORIPEX retrospective study.

ABSTRACT: Switching dual therapy with dolutegravir (DTG) plus rilpivirine (RPV) was assessed in the SWORD-1 and SWORD-2 studies. Real-life data regarding the immunological impact of this approach on CD4+ and CD8+ T lymphocyte counts and the CD4/CD8 ratio are scarce. We evaluated this strategy on the basis of clinical practice data.A multicentric retrospective cohort study.Treatment-experienced virologically suppressed HIV-1-infected patients who were switched to DTG plus RPV were included. Using different models for paired data, we evaluated the efficacy and immune status in terms of CD4+ and CD8+ T-cell counts and CD4/CD8 ratio at 24 and 48 weeks of treatment.The study population comprised of 524 patients from 34 centers in Spain. Men accounted for 76.9% of patients, with a median age of 53 years. Patients receiving DTG plus RPV reached weeks 24 and 48 in 99.4% and 83.8% of cases, respectively, with only three (0.57%) virological failures. We found a significant decrease in CD8+ T-cell count (log OR -40) at week 24 and an increase in CD4+ T-cell count at week 48 (log OR +22.8). In acquired immunodeficiency syndrome-diagnosed patients, we found a significant increase in the CD4+ T-cell count at week 48 (log OR = 41.7, P = .0038), but no significant changes in the CD8+ T-cell count (log OR = -23.4, P = .54). No differences were found in the CD4/CD8 ratio between the acquired immunodeficiency syndrome subgroup and sex or age.In patients with controlled treatment, dual therapy with DTG plus RPV slightly improved the immune status during the first 48 weeks after switching, not only in terms of CD4+ T-cell count but also in terms of CD8+ T-cell count, with persistently high rates of viral control.