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Background Bacteria have developed different mechanisms for the transformation of metalloid oxyanions to non-toxic chemical forms. A number of bacterial isolates so far obtained in axenic culture has shown the ability to bioreduce selenite and tellurite to the elemental state in different conditions along with the formation of nanoparticles—both inside and outside the cells—characterized by a variety of morphological features. This reductive process can be considered of major importance for two reasons: firstly, toxic and soluble (i.e. bioavailable) compounds such as selenite and tellurite are converted to a less toxic chemical forms (i.e. zero valent state); secondly, chalcogen nanoparticles have attracted great interest due to their photoelectric and semiconducting properties. In addition, their exploitation as antimicrobial agents is currently becoming an area of intensive research in medical sciences. Results In the present study, the bacterial strain Ochrobactrum sp. MPV1, isolated from a dump of roasted arsenopyrites as residues of a formerly sulfuric acid production near Scarlino (Tuscany, Italy) was analyzed for its capability of efficaciously bioreducing the chalcogen oxyanions selenite (SeO 3 2− ) and tellurite (TeO 3 2− ) to their respective elemental forms (Se 0 and Te 0 ) in aerobic conditions, with generation of Se- and Te-nanoparticles (Se- and TeNPs). The isolate could bioconvert 2 mM SeO 3 2− and 0.5 mM TeO 3 2− to the corresponding Se 0 and Te 0 in 48 and 120 h, respectively. The intracellular accumulation of nanomaterials was demonstrated through electron microscopy. Moreover, several analyses were performed to shed light on the mechanisms involved in SeO 3 2− and TeO 3 2− bioreduction to their elemental states. Results obtained suggested that these oxyanions are bioconverted through two different mechanisms in Ochrobactrum sp. MPV1. Glutathione (GSH) seemed to play a key role in SeO 3 2− bioreduction, while TeO 3 2− bioconversion could be ascribed to the catalytic activity of intracellular NADH-dependent oxidoreductases. The organic coating surrounding biogenic Se- and TeNPs was also characterized through Fourier-transform infrared spectroscopy. This analysis revealed interesting differences among the NPs produced by Ochrobactrum sp. MPV1 and suggested a possible different role of phospholipids and proteins in both biosynthesis and stabilization of such chalcogen-NPs. Conclusions In conclusion, Ochrobactrum sp. MPV1 has demonstrated to be an ideal candidate for the bioconversion of toxic oxyanions such as selenite and tellurite to their respective elemental forms, producing intracellular Se- and TeNPs possibly exploitable in biomedical and industrial applications.

Background Large-scale cultivation of microalgae provides a carbon–neutral source of biomass for extracting valuable compounds and producing renewable fuels. Owing to their high metabolic activity and rapid reproduction rates, Chlorella species are highly productive when grown in photobioreactors. However, wild-type strains have some biological limitations that make algal bioproducts more expensive than those from more traditional sources. Domestication is thus required for improving strains. Engineering Chlorella species has been made difficult by their chemically complex and highly resistant cell wall, making transformation difficult. Cell wall also restricts diffusion of organic solvents; thus, limiting the extraction of valuable intracellular compounds. Obtaining strains with weakened cell wall is crucial to enhance the extractability of intracellular molecules, reducing the costs of biomass disruption, and to improve genetic transformation efficiency. Results We developed a mutagenesis pipeline combined with single-cell fluorescence scanning on the microalga Chlorella vulgaris to identify mutants with altered cell wall properties. We used the fluorescent dyes erythrosin B and calcofluor white, as markers for cell wall permeability and for binding the structural polysaccharides of the cell wall, respectively. Flow cytometry with fluorescence-activated cell sorting was employed to enrich mutagenized populations with altered emission profiles. After a first round of mutagenesis, we found six mutants with significantly higher cell permeability to erythrosin B than the wild type (CWP lines) and altered cell wall structure and composition. A second round of mutagenesis on a selected CWP strain, followed by selection for lower calcofluor white signal, resulted in the isolation of CFW lines, which exhibited reduced mechanical resistance when the biomass was subjected to cell disruption procedures. This two-steps procedure allowed us to identify new mutant strains with both an increased cell wall permeability and a reduced mechanical resistance, making a novel step towards Chlorella domestication. Conclusions This study demonstrated the feasibility of using mutagenesis and phenotypic selection based on flow cytometry screening to alter the cell wall of C. vulgaris and identify promising strains with improved traits for industrial applications.

To introduce the fundamental concepts and formalism of Quantum Mechanics at the base of Quantum Calculus and Quantum Cryptography we developed an experiment-based module centered on the use of a Mach-Zehnder laser interferometer equipped with linear polarizers. By analyzing the constructive and destructive interference, students are guided to understand the meaning of mutual exclusivity and incompatibility of polarization states (H, V) and (45°, 135°). A MATLAB simulation allows the understanding of the experimental results in terms of single photons. The module was tested as a pilot intervention on a group of Computer Science PhD students at the University of Verona.

This paper proposes a parsimonious and model-consistent method for combining forecasts generated by structural microfounded models and judgmental forecasts. The method delivers along several dimensions. First, it improves the forecasting performance of the model. Second, it allows interpreting the judgmental forecasts through the lens of the model. Finally, it provides a framework to assess the informational content of the judgmental forecasters. I illustrate the proposed methodology with a real-time forecasting exercise using a simple neo-Keynesian dynamic stochastic general equilibrium model and the Survey of Professional Forecasters.

The evaluation of cell parietal components of yeasts is an important criterium for the selection of wine starters since they play a key role in the vinification process. The aim of this study was to characterize and compare the cell wall composition of four industrial (BM45, D47, EC1118, K1) and three native Saccharomyces cerevisiae (MY8, MY11, PEDRO2000E) wine strains by means of scanning and transmission electron microscopy and ATR-FTIR microspectroscopy. A statistically significant variability in the cell wall thickness and cell diameter was observed among the yeast cells, with native strains showing higher cell diameter values. FTIR microspectroscopy applied on the intact cells without any previous invasive treatment and on the separated cell walls highlighted profound differences among the strains in terms of the overall content of parietal polysaccharides as related to the thickness of the cell walls and in terms of the relative concentration of β-glucans and mannans in the cell walls. The strains EC1118, MY11, and PEDRO2000E showed a higher overall content of β-glucans and mannans, whose lower relative concentration in PEDRO2000E was compensated by a thicker cell wall; BM45 and D47 were characterized by a high relative concentration of polysaccharides in a thinner wall, while K1 and MY8 displayed a low relative concentration of polysaccharides. ATR-FTIR microspectroscopy allows identifying polysaccharide-rich yeast strains and can become a smart option for the selection of starter cultures to be used in oenology and for other applications in food industry, thanks to the interesting technological properties of parietal polysaccharides.

Applied optics offers a way to teach fundamental concepts of light properties and radiation-matter interaction through interdisciplinary experimental activities. In this framework, we designed a cross-disciplinary laboratorial activity on optics applied to artworks based on DIY instrumentation for the secondary school level. The teaching sequence includes inquiry-based seminars and laboratorial activities on imaging, spectrometry, infrared applications to conservation science.

• Expansins are cell wall proteins required for cell enlargement and cell wall loosening during many developmental processes. The involvement of the Petunia hybrida expansin A1 (PhEXPA1) gene in cell expansion, the control of organ size and cell wall polysaccharide composition was investigated by overexpressing PhEXPA1 in petunia plants. • PhEXPA1 promoter activity was evaluated using a promoter-GUS assay and the protein's subcellular localization was established by expressing a PhEXPA1-GFP fusion protein. PhEXPA1 was overexpressed in transgenic plants using the cauliflower mosaic virus (CaMV) 35S promoter. Fourier transform infrared (FTIR) and chemical analysis were used for the quantitative analysis of cell wall polymers. • The GUS and GFP assays demonstrated that PhEXPA1 is present in the cell walls of expanding tissues. The constitutive overexpression of PhEXPA1 significantly affected expansin activity and organ size, leading to changes in the architecture of petunia plants by initiating premature axillary meristem outgrowth. Moreover, a significant change in cell wall polymer composition in the petal limbs of transgenic plants was observed. • These results support a role for expansins in the determination of organ shape, in lateral branching, and in the variation of cell wall polymer composition, probably reflecting a complex role in cell wall metabolism.

In recent years dynamic stochastic general equilibrium models have emerged as important tools for forecasting and policy analysis, thanks to their attractive theoretical features and their improved forecasting ability. The recent crisis has brought new relevance to this question; key causes of the crisis and its protraction, such as the housing market, financial markets, the labour market and the fiscal sector, are often very stylised or missing in most policy macro-models. But if the model misses some crucial aspects of the economy's dynamics, then economists must expand the model to include those features. They therefore need tools to assess which of these channels and transmission mechanisms are relevant at various points in the conjuncture. This paper aims to make progress in this direction. The proposal is to exploit a data-rich environment and focus on the interaction between a large number of macroeconomic variables and the model to capture the likely sources and magnitude of the model misspecification.

Heterogeneous beliefs modify the New Keynesian Phillips curve by introducing a term in the cross-section distribution of expectations. We develop a novel functional data approach to estimation and inference in survey-based Phillips curves that accounts for variation in distributions of expectations, generalizing standard approaches. Our findings demonstrate the statistical and economic importance of heterogeneous beliefs for inflation dynamics, especially during periods of macroeconomic disruption.Our findings hold in similar form across two major economies.

We establish a set of novel empirical facts concerning cross-section distributions of inflation expectations reported in surveys. Almost all the variation in expectations about their mean may be summarized via three factors we call disagreement, skew, and shape. We adopt a functional principal component regression approach to estimating forward-looking models of inflation that exploits the heterogeneity present in individual-level data. By using survey information more effectively, our approach reveals an enhanced role for expectations in inflation dynamics that is robust to lagged inflation, trend inflation, and supply factors. Our findings hold in similar form across two major economies.