Rapidly Solidified Melt-spun Bi-Sn Ribbons: Surface Composition Issues

Tin-bismuth alloy ribbons were produced using melt-spinning technique. The two main surfaces (in contact with the rotating wheel and exposed to the air) were characterized with Optical Microscopy and AFM, revealing that the surface exposed to the air is duller (due to a long-range heterogeneity) than the opposite surface. Also the XPS chemical composition revealed many differences between them both on the corrosion extension and on the total relative amounts of tin and bismuth. For instance, for the specific case of an alloy with a composition Bi-4 wt % Sn, the XPS atomic ratios Sn/Bi are 1.1 and 3.7 for the surface in contact with the rotating wheel and for the one exposed to air, respectively, showing, additionally, that a large segregation of tin at the surface exists (nominal ratio should be 0.073). This segregation was interpreted as the result of the electrochemical process yielding the corrosion products

Quinone oxidoreductase from Staphylococcus aureus

Funding Information: Helena Gaspar is acknowledged for the HPLC analyses and Bruno Victor for advice on modelling. F.M.S. and M.S.S. are recipients of fellowships by Fundação para a Ciência e a Tecnologia (PD/BD/128213/2016 and PD/BD/128202/2016, respectively, both within the scope of the PhD program Molecular Biosciences PD/00133/2012). A.B. is recipient of a fellowship by Fundação para a Ciência e a Tecnologia UI/BD/153052/2022. The work was funded by Fundação para a Ciência e a Tecnologia ( PTDC/BIA-BQM/2599/2021 to M.M.P). The project was further supported by UIDB/04046/2020 and UIDP/04046/2020 Centre grants from FCT , Portugal (to BioISI), by LISBOA-01-0145-FEDER-007660 cofunded by FEDER through COMPETE2020-POCI and by Fundação para a Ciência e a Tecnologia and by UIDB/04612/2020 and UIDP/04612/2020 research unit grants from FCT (to Mostmicro). The NMR spectrometers are part of the National NMR Network (PTNMR) and are supported by Infrastructure Project N° 022161 (co-financed by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC). Funding Information: Helena Gaspar is acknowledged for the HPLC analyses and Bruno Victor for advice on modelling. F.M.S. and M.S.S. are recipients of fellowships by Fundação para a Ciência e a Tecnologia (PD/BD/128213/2016 and PD/BD/128202/2016, respectively, both within the scope of the PhD program Molecular Biosciences PD/00133/2012). A.B. is recipient of a fellowship by Fundação para a Ciência e a Tecnologia UI/BD/153052/2022. The work was funded by Fundação para a Ciência e a Tecnologia (PTDC/BIA-BQM/2599/2021 to M.M.P). The project was further supported by UIDB/04046/2020 and UIDP/04046/2020 Centre grants from FCT, Portugal (to BioISI), by LISBOA-01-0145-FEDER-007660 cofunded by FEDER through COMPETE2020-POCI and by Fundação para a Ciência e a Tecnologia and by UIDB/04612/2020 and UIDP/04612/2020 research unit grants from FCT (to Mostmicro). The NMR spectrometers are part of the National NMR Network (PTNMR) and are supported by Infrastructure Project N° 022161 (co-financed by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC). Publisher Copyright: © 2022 The Author(s)Staphylococcus aureus is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial bacterial infections. Even so, its energy metabolism is still under explored and its respiratory enzymes have been vastly overlooked. In this work, we unveil the dihydroorotate:quinone oxidoreductase (DHOQO) from S. aureus, the first example of a DHOQO from a Gram-positive organism. This protein was shown to be a FMN containing menaquinone reducing enzyme, presenting a Michaelis-Menten behaviour towards the two substrates, which was inhibited by Brequinar, Leflunomide, Lapachol, HQNO, Atovaquone and TFFA with different degrees of effectiveness. Deletion of the DHOQO coding gene (Δdhoqo) led to lower bacterial growth rates, and effected in cell morphology and metabolism, most importantly in the pyrimidine biosynthesis, here systematized for S. aureus MW2 for the first time. This work unveils the existence of a functional DHOQO in the respiratory chain of the pathogenic bacterium S. aureus, enlarging the understanding of its energy metabolism.publishersversionpublishe

Mechanical Properties of Human Bronchial Epithelial Cells Expressing Wt- and Mutant CFTR

Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). A single recessive mutation, the deletion of phenylalanine 508 (F508del), causes severe CF and resides on 70% of mutant chromosomes. Disorganization of the actin cytoskeleton has been previously reported in relation to the CF phenotype. In this work, we aimed to understand this alteration by means of Atomic Force Microscopy and Force Feedback Microscopy investigation of mechanical properties of cystic fibrosis bronchial epithelial (CFBE) cells stably transduced with either wild type (wt-) or F508del-CFTR. We show here that the expression of mutant CFTR causes a decrease in the cell’s apparent Young modulus as compared to the expression of the wt protein