Towards high-resolution water isotope analysis in ice cores using laser ablation - cavity ring-down spectroscopy.

A new micro-destructive technique for high-resolution water isotope analysis of ice samples using a Laser Ablation (LA) system coupled with a Cavity Ring Down Spectrometer (CRDS) is presented. This method marks the first time water isotope analysis is conducted directly on the ice, bypassing the traditional steps of melting and vaporizing the ice sample, thanks to the direct transition of ice into water vapour through the laser ablation process. A nanosecond ArF laser ablation system (193 nm) with an integrated two-volume ablation chamber was successfully coupled to a CRDS analyzer, utilizing nitrogen as the carrier gas.

The actinomycete Kitasatospora sp. SeTe27, subjected to adaptive laboratory evolution (ALE) in the presence of selenite, varies its cellular morphology, redox stability, and tolerance to the toxic oxyanion.

The effects of oxyanions selenite (SeO) in soils are of high concern in ecotoxicology and microbiology as they can react with mineral particles and microorganisms. This study investigated the evolution of the actinomycete Kitasatospora sp. SeTe27 in response to selenite.

Insights into the Synergistic Antibacterial Activity of Silver Nitrate with Potassium Tellurite against .

The constant, ever-increasing antibiotic resistance crisis leads to the announcement of "urgent, novel antibiotics needed" by the World Health Organization. Our previous works showed a promising synergistic antibacterial activity of silver nitrate with potassium tellurite out of thousands of other metal/metalloid-based antibacterial combinations. The silver-tellurite combined treatment not only is more effective than common antibiotics but also prevents bacterial recovery, decreases the risk of future resistance chance, and decreases the effective concentrations.

An upgraded CFA - FLC - MS/MS system for the semi-continuous detection of levoglucosan in ice cores.

A new Continuous Flow Analysis (CFA) system coupled with Fast Liquid Chromatography - tandem Mass Spectrometry (FLC-MS/MS) has been recently developed for determining organic markers in ice cores. In this work we present an upgrade of this innovative technique, optimized for the detection of levoglucosan in ice cores, a crucial tracer for reconstructing past fires. The upgrade involved a specific optimization of the chromatographic and mass spectrometric parameters, allowing for a higher sampling resolution (down to 1 cm) and the simultaneous collection of discrete samples, for off-line analysis of water stable isotopes and additional chemical markers.

Non-Equilibrium Fractionation Factors for D/H and O/O During Oceanic Evaporation in the North-West Atlantic Region.

Ocean isotopic evaporation models, such as the Craig-Gordon model, rely on the description of nonequilibrium fractionation factors that are, in general, poorly constrained. To date, only a few gradient-diffusion type measurements have been performed in ocean settings to test the validity of the commonly used parametrization of nonequilibrium isotopic fractionation during ocean evaporation. In this work, we present 6 months of water vapor isotopic observations collected from a meteorological tower located in the northwest Atlantic Ocean (Bermuda) with the objective of estimating nonequilibrium fractionation factors (, ‰) for ocean evaporation and their wind speed dependency.

Tolerance, Adaptation, and Cell Response Elicited by sp. Facing Tellurite Toxicity: A Biological and Physical-Chemical Characterization.

The intense use of tellurium (Te) in industrial applications, along with the improper disposal of Te-derivatives, is causing their accumulation in the environment, where oxyanion tellurite (TeO) is the most soluble, bioavailable, and toxic Te-species. On the other hand, tellurium is a rare metalloid element whose natural supply will end shortly with possible economic and technological effects. Thus, Te-containing waste represents the source from which Te should be recycled and recovered.

Tellurite and Selenite: how can these two oxyanions be chemically different yet so similar in the way they are transformed to their metal forms by bacteria?

This opinion review explores the microbiology of tellurite, TeO and selenite, SeO oxyanions, two similar Group 16 chalcogen elements, but with slightly different physicochemical properties that lead to intriguing biological differences. Selenium, Se, is a required trace element compared to tellurium, Te, which is not. Here, the challenges around understanding the uptake transport mechanisms of these anions, as reflected in the model organisms used by different groups, are described.

Fast Liquid Chromatography Coupled with Tandem Mass Spectrometry for the Analysis of Vanillic and Syringic Acids in Ice Cores.

The development of new analytical systems and the improvement of the existing ones to obtain high-resolution measurements of chemical markers in samples from ice cores, is one of the main challenges the paleoclimatic scientific community is facing. Different chemical species can be used as markers for tracking emission sources or specific environmental processes. Although some markers, such as methane sulfonic acid (a proxy of marine productivity), are commonly used, there is a lack of data on other organic tracers in ice cores, making their continuous analysis analytically challenging.

Transcriptomic Analysis of the Dual Response of Rhodococcus aetherivorans BCP1 to Inorganic Arsenic Oxyanions.

Bacterial strains belonging to the genus are able to degrade various toxic organic compounds and tolerate high concentrations of metal(loid)s. We have previously shown that Rhodococcus aetherivorans BCP1 is resistant to various levels of the two arsenic inorganic species, arsenite [As(III)] and arsenate [As(V)]. However, while arsenite showed toxic effects at concentrations as low as 5 mM, arsenate at 30 mM boosted the growth rate of BCP1 cells and was toxic only at concentrations of >100 mM.

Sediment quality of the Ridracoli fresh water reservoir in Italy: Insights from aqua regia digestion and sequential extractions.

The inter-element relationships and the forms in which metals exist strongly influence their mobility and, in turn, have a signature on the environment and human health. Located in the northern Apennines within the Emilia-Romagna region, the Ridracoli artificial lake is one of Italy's most important reservoirs that provides drinking water for about one million people. This work characterized the reservoir sediments by ICP-MS after aqua regia digestion (ARD), comparing the limits by law to assess environmental compliance and XRF data from the same sample-set taken as total concentrations.

Methods for radioactivity measurements in drinking water using gamma spectrometry.

In this study, three methods to measure activity concentrations of radionuclides through high resolution gamma spectrometry are developed, optimized, and tested on drinking water samples. Two pre-concentration methods (partial evaporation and ion-exchange resins) were optimized for accuracy, precision, detection limits, costs, preparation, and measurements times. A new sampling method for Rn was designed and optimized to directly sample water from the tap, reducing and minimizing losses of radon during the sampling.

Molecular characterization of microbial communities in a peat-rich aquifer system contaminated with chlorinated aliphatic compounds.

In an aquifer-aquitard system in the subsoil of the city of Ferrara (Emilia-Romagna region, northern Italy) highly contaminated with chlorinated aliphatic toxic organics such as trichloroethylene (TCE) and tetrachloroethylene (PCE), a strong microbial-dependent dechlorination activity takes place during migration of contaminants through shallow organic-rich layers with peat intercalations. The in situ microbial degradation of chlorinated ethenes, formerly inferred by the utilization of contaminant concentration profiles and Compound-Specific Isotope Analysis (CSIA), was here assessed using Illumina sequencing of V4 hypervariable region of 16S rRNA gene and by clone library analysis of dehalogenase metabolic genes. Taxon-specific investigation of the microbial communities catalyzing the chlorination process revealed the presence of not only dehalogenating genera such as Dehalococcoides and Dehalobacter but also of numerous other groups of non-dehalogenating bacteria and archaea thriving on diverse metabolisms such as hydrolysis and fermentation of complex organic matter, acidogenesis, acetogenesis, and methanogenesis, which can indirectly support the reductive dechlorination process.

Processing of Metals and Metalloids by : Cell Resistance Mechanisms and Synthesis of Metal(loid)-Based Nanostructures.

Metal(loid)s have a dual biological role as micronutrients and stress agents. A few geochemical and natural processes can cause their release in the environment, although most metal-contaminated sites derive from anthropogenic activities. Actinobacteria include high GC bacteria that inhabit a wide range of terrestrial and aquatic ecological niches, where they play essential roles in recycling or transforming organic and inorganic substances.

Biotechnology of Rhodococcus for the production of valuable compounds.

Bacteria belonging to Rhodococcus genus represent ideal candidates for microbial biotechnology applications because of their metabolic versatility, ability to degrade a wide range of organic compounds, and resistance to various stress conditions, such as metal toxicity, desiccation, and high concentration of organic solvents. Rhodococcus spp. strains have also peculiar biosynthetic activities that contribute to their strong persistence in harsh and contaminated environments and provide them a competitive advantage over other microorganisms.

Structural and electrochemical characterization of lawsone-dependent production of tellurium-metal nanoprecipitates by photosynthetic cells of Rhodobacter capsulatus.

Cells of the facultative photosynthetic bacterium Rhodobacter capsulatus exploit the simultaneous presence in the cultural medium of the toxic oxyanion tellurite (TeO) and the redox mediator lawsone (2-hydroxy-1,4-naphthoquinone) by reducing tellurite to metal Te nanoprecipitates (TeNPs) outside the cells. Here we have studied the mechanism by which lawsone interacts with metabolically active cells and analysed both structure and composition of the TeNPs collected from the growth medium of phototrophycally grown R. capsulatus.

Methodology choice could affect air quality interpretation? A case study for an international airport, Marco Polo, Venice.

Venice Marco Polo Airport (VCE) is one of the most important airport of Italy, but is also placed in a delicate context; due to the proximity of the airport to the Venice historical city and the fragile ecosystem of the Lagoon that surround the city. For all these reasons the priority was to assess the possible impact of Marco Polo Airport in Venice area. For this reason a collaboration between Save Spa, the company that manage Marco Polo airport, and the Department of Environmental Sciences, Informatics and Statistics, of Ca' Foscari University was stated in order to: (I) understand the impact on air quality of an airport structure in a vulnerable context (II)analyze the airport emission trend (III) analyze how the number of flights and aircraft type can influence emission.

Identification of Resistance Genes and Response to Arsenic in BCP1.

Arsenic (As) ranks among the priority metal(loid)s that are of public health concern. In the environment, arsenic is present in different forms, organic or inorganic, featured by various toxicity levels. Bacteria have developed different strategies to deal with this toxicity involving different resistance genetic determinants.

Human and environmental factors affecting the activity of I and Cs in urban wastewater: A case study.

The analysis of radionuclides content in the waste product of urban wastewater treatment (i.e. sewage sludges) is of great concern for both the safety of workers and in a re-use perspective of the final product.

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves.

Chemical mobility of crystalline and amorphous SiO plays a fundamental role in several geochemical and biological processes, with silicate minerals being the most abundant components of the Earth's crust. Although the oldest evidences of life on Earth are fossilized in microcrystalline silica deposits, little is known about the functional role that bacteria can exert on silica mobility at non-thermal and neutral pH conditions. Here, a microbial influence on silica mobilization event occurring in the Earth's largest orthoquartzite cave is described.

Some facts about the respiratory enzymes of Pseudomonas pseudoalcaligenes KF707 recently renamed as Pseudomonas furukawaii sp. nov., type strain KF707.

Kimura and co-workers (Kimura N et al. Int J Syst Evol Microbiol 2018;68:1429-1435) recently proposed renaming the obligate aerobe Pseudomonas pseudoalcaligenes KF707 as Pseudomonas furukawiisp. nov.

Aerobic Growth of BCP1 Using Selected Naphthenic Acids as the Sole Carbon and Energy Sources.

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability.

Assembly, growth and conductive properties of tellurium nanorods produced by Rhodococcus aetherivorans BCP1.

Tellurite (TeO) is a hazardous and toxic oxyanion for living organisms. However, several microorganisms can bioconvert TeO into the less toxic form of elemental tellurium (Te). Here, Rhodococcus aetherivorans BCP1 resting (non-growing) cells showed the proficiency to produce tellurium-based nanoparticles (NPs) and nanorods (NRs) through the bioconversion of TeO, depending on the oxyanion initial concentration and time of cellular incubation.