Arsenic-resistant bacteria isolated from contaminated sediments of the Orbetello Lagoon, Italy, and their characterization

AIMS: The aim of this study was to isolate arsenic-resistant bacteria from contaminated sediment of the Orbetello Lagoon, Italy, to characterize isolates for As(III), As(V), heavy metals resistance, and from the phylogenetic point of view. METHODS AND RESULTS: Enrichment cultures were carried out in the presence of 6.75 mmol l(-1) of As(III), allowing isolation of ten bacterial strains. Four isolates, ORAs1, ORAs2, ORAs5 and ORAs6, showed minimum inhibitory concentration values equal or superior to 16.68 mmol l(-1) and 133.47 mmol l(-1) in the presence of As(III) and As(V), respectively. Isolate ORAs2 showed values of 1.8 mmol l(-1) in the presence of Cd(II) and 7.7 mmol l(-1) of Zn(II), and isolate ORAs1 pointed out a value of 8.0 mmol l(-1) in the presence of Cu(II). Analysis of 16S rRNA gene sequences revealed that they can be grouped in the three genera Aeromonas, Bacillus and Pseudomonas. Phylogenetic analysis of the four more arsenic-resistant strains was also performed. CONCLUSION: Isolates are highly resistant to both As(III) and As(V) and they could represent good candidates for bioremediation processes of native polluted sediments. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides original results on levels of resistance to arsenic and to assigning genera of bacterial strains isolated from arsenic-polluted sediments

Arsenic precipitation by an anaerobic arsenic-respiring bacterial strain isolated from the polluted sediments of Orbetello Lagoon, Italy

AIMS: To isolate and characterize an anaerobic bacterial strain from the deeper polluted lagoon sediment able to use as electron acceptors [As(V)] and sulfate (SO4(2-)), using lactate as an electron donor. METHODS AND RESULTS: Methods for isolation from polluted lagoon sediments included anaerobic enrichment cultures in the presence of As(V) and SO4(2-). Reduction of As(V) to As(III) was observed during the growth of the bacterial strain, and the final concentration of As(III) was lower than the initial As(V) one, suggesting the immobilization of As(III) in the yellow precipitate. The precipitate was identified by energy dispersive spectroscopy X-ray as arsenic sulfide. Scanning electron microscopy (SEM) revealed rod-shaped bacterial cells embedded in the precipitate, where net-like formations strictly related to the bacterial cells were visible. The surface of the precipitate showed the adhesion of bacterial cells, forming clusters. Transmission electron microscopy (TEM) also highlighted precipitates inside the bacterial cells and on their surface. Following 16S rRNA sequencing, the bacterial strain 063 was assigned to the genus Desulfosporosinus. CONCLUSIONS: This study reports, for the first time, the isolation from the polluted lagoon sediments of a strain capable of respiring and using As(V) and SO4(2-) as electron acceptors with lactate as the sole carbon and energy source with the formation of an arsenic sulfide precipitate. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of these properties provides novel insight into the possible use of the anaerobic strain in bioremediation processes and also adds to the knowledge on the biogeochemical cycling of arsenic

Measuring emptiness: Validation of the Italian version of the Subjective Emptiness Scale in clinical and non-clinical populations

Background: Although a feeling of emptiness is listed only as a symptom of the DSM-5 borderline personality disorder, it is commonly encountered in other disorders. The aim of this study was to validate the Italian version of the Subjective Emptiness Scale (SES-I), a 7-item self-report instrument assessing the feeling of emptiness. Methods: Participants in one clinical group (n = 63) and one non-clinical group (n = 48) completed the SES-I along with several other instruments. A principal component analysis was used to analyze the structure of the SES-I and Cronbach's alpha and Rho's Spearman were used to establish aspects of reliability and validity, respectively. Results: The SES-I has a unidimensional structure reflecting the core feature of the feeling of emptiness. It showed an excellent internal consistency (a = 0.92) and convergent validity, as demonstrated by significant correlations with scores on the Beck Depression Inventory – II and conceptually related scales and subscales of the Millon Clinical Multiaxial Inventory – III and Personality Inventory for DSM-5. Divergent validity was also demonstrated for the SES-I. SES-I scores in the clinical group were significantly higher than in the non-clinical group. A significant relationship was not found between the feeling of emptiness and self-harming behavior, impulsivity and acting-out. Limitations: A small sample size, several significant differences between the clinical and non-clinical groups and diagnostic heterogeneity in the clinical group limit generalizability of the study. Conclusion: The SES-I is a valid and reliable instrument, which should improve assessment of the feeling of emptiness and help clinicians better understand this complex phenomenon

Metallurgical and statistical approaches to the study of cast iron street furniture

The evolution of microstructure in relation to dating and nationality of origin was investigated in twenty-four cast iron objects of street furniture produced between XIX and XX centuries in United Kingdom, France, and Italy. Chemical composition of the metalworks was evaluated by glow-discharge optical emission spectrometry. Fragments from the cast irons were analyzed by optical microscopy and scanning electron microscopy with energy-dispersive spectroscopy. Form, distribution, and size of graphite were evaluated in the microstructure according to standard EN ISO 945-1:2008. An image analysis software was employed to quantify the area fraction of graphite in the matrix, major axis, and shape factor of graphite lamellae, area fraction of manganese sulfides (ψS), area fraction of steadite, and number of eutectic cells per area unit. All data were grouped and linear discrimination analysis (LDA) was applied to assess the group assignment and the probability of correct classification for each metalwork. The results showed that the microstructural features were compatible with those of cast irons produced in the XIX and XX centuries. Values of ψS also suggested re-melting of cast irons, associated with recycling of cast iron and/or steel scraps. The high values of steadite found in the metalworks are probably due to the excellent castability required for complex shape castings in these centuries. The LDA multivariate analysis allowed to discriminate cast irons based on the year of manufacturing and the nationality of origin

Role of the tricuspid annulus in functional tricuspid regurgitation development after early isolated mitral valve surgery: is it an old story?

Abstract Funding Acknowledgements Type of funding sources: None. Background. Functional Tricuspid Regurgitation (FTR) has been described as a common condition after isolated mitral valve (MV) surgery, affecting patients' prognosis. Thus, in cases without significant tricuspid regurgitation (TR) but tricuspid annular (TA) dilatation, TV annuloplasty is currently recommended. Studies suggesting the currently used cut-off for definition of TA dilatation were based on 2D echocardiography (2DE) and included patients treated with MV surgery with heterogeneous MV disease, degree of cardiac remodeling and heart rhythm. As the management of severe MR has moved towards an earlier surgical treatment, few data are available about the incidence of FTR in the population undergoing early isolated MV surgery without TR, but 2DE satisfying criteria for TA dilatation. Aims. To test, in patients treated with early isolated MV surgery for MV prolapse (MVP), without TR and either normal or dilated TA (i) if the currently used 2D TA cut-off is predictive of FTR and cardiac events development (ii) how right chambers' remodeling assessed by 3D echocardiography (3DE) affects TA dimension. Methods. We studied 159 patients (age 61 ± 11) treated with early isolated MV surgery between 2010 and 2017. Eligible patients were those with 3DE images; normal left and right ventricular (LV and RV) function; sinus rhythm; normal or elevated right ventricular systolic pulmonary artery pressure (sPAP); normal or dilated TA by 2DE; absent TR. The decision to not perform TV annuloplasty in patients with TA dilatation was based on the surgical inspection. All patients underwent a complete 2DE, 3DE analysis was performed using custom software, including LV, RV, left atrial (LA) and right atrial (RA) assessment. 3D TA dimension were obtained using MPR. Clinical and 2DE follow-up was performed at 36 ± 6 months after surgery, major adverse cardiac events (MACEs, including cardiac hospitalization, cardiac death, arrhythmias) and FTR were recorded. Results. Based on 2DE TA dimensions, patients were divided in group 1 (N = 68, 43%, TA≥21 mm/m²) and group 2 (N= 91, 57%, normal TA). Patients in group 1 showed larger RA volume, RV basal diameter and TA area (p < 0.05) by 3DE compared to group 2 (Table). At the multivariate analysis, only the 3D RA volume, RV basal diameter and RV function were independently correlated to the TA area (p < 0.05). At the follow-up, no differences were noted between groups in FTR development and MACEs at the Kaplan-Meier analysis (Fig.). At the COX analysis, 2DE TA dilatation failed to result a predictor of cardiovascular events (model's X2, p > 0.05). Conclusions. In patients undergoing early MV surgery, the currently defined TA dilatation by 2DE may not necessarily evolve in FTR, and a larger cut-off may be needed. In this population, the evaluation of right chambers' dimension and function may better define the probability to develop FTR. Abstract Figure. Fi

Free N-heterocyclic carbenes from Brønsted acidic ionic liquids: Direct detection by electrospray ionization mass spectrometry

Rationale: The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry. Methods: Three different Brønsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAI - H). The speciation of these compounds was then analysed by electrospray ionization ion-trap mass spectrometry in the negative ion mode. Results: The C2-H deprotonation of the imidazolium cation leading to the formation of the corresponding carbene is highly affected by the basic properties of the counter-anion. In the case of MAICl and MAI - H ionic liquids, no charged species corresponding to the free N-heterocyclic carbene was detected. On the contrary, in the presence of a sufficiently basic anion, such as acetate of MAIAc ionic liquid, an intense signal related to the free carbenic species was observed without the addition of an external base. Conclusions: In situ formation of free N-heterocyclic carbenes from Brønsted acidic ionic liquids was demonstrated, highlighting the crucial role of anion basicity in promoting the C2-H proton abstraction from imidazolium cations with a carboxylic side chain.Rationale The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry. Methods Three different Bronsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAI - H). The speciation of these compounds was then analysed by electrospray ionization ion-trap mass spectrometry in the negative ion mode. Results The C2-H deprotonation of the imidazolium cation leading to the formation of the corresponding carbene is highly affected by the basic properties of the counter-anion. In the case of MAICl and MAI - H ionic liquids, no charged species corresponding to the free N-heterocyclic carbene was detected. On the contrary, in the presence of a sufficiently basic anion, such as acetate of MAIAc ionic liquid, an intense signal related to the free carbenic species was observed without the addition of an external base. Conclusions In situ formation of free N-heterocyclic carbenes from Bronsted acidic ionic liquids was demonstrated, highlighting the crucial role of anion basicity in promoting the C2-H proton abstraction from imidazolium cations with a carboxylic side chain