X-ray dynamical diffraction in amino acid crystals: a step towards improving structural resolution of biological molecules via physical phase measurements

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPIn this work, experimental and data analysis procedures were developed and applied for studying amino acid crystals by means of X-ray phase measurements. The results clearly demonstrated the sensitivity of invariant triplet phases to electronic charge distribution in D-alanine crystals, providing useful information for molecular dynamics studies of intermolecular forces. The feasibility of using phase measurements to investigate radiation damage mechanisms is also discussed on experimental and theoretical grounds.50689700CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP306982/2012-9452031/2015-02012/01367-212/15858-814/08819-114/21284-016/11812-4Acknowledgments are due to the Brazilian funding agencies CNPq (grant Nos. 306982/2012-9 and 452031/20150) and FAPESP (grant Nos. 2012/01367-2, 12/15858-8, 14/08819-1, 14/21284-0 and 16/11812-4), Diamond Light Source (proposal MT11922), and the Brazilian Synchrotron Light Source (proposals 17063, 18011 and 19018). We also thank Professor Lisandro P. Cardoso, Dr Steven Collins and Dr José Brandão-Neto for helpful discussions

The Egas Moniz histology digital platform : a dream that came true

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Sulforaphane induces oxidative stress and death by p53-independent mechanism: implication of impaired glutathione recycling

Sulforaphane (SFN) is a naturally-occurring isothiocyanate best known for its role as an indirect antioxidant. Notwithstanding, in different cancer cell lines, SFN may promote the accumulation of reactive oxygen species (ROS) and cause cell death e.g. by apoptosis. Osteosarcoma often becomes chemoresistant, and new molecular targets to prevent drug resistance are needed. Here, we aimed to determine the effect of SFN on ROS levels and to identify key biomarkers leading to ROS unbalance and apoptosis in the p53-null MG-63 osteosarcoma cell line. MG-63 cells were exposed to SFN for up to 48 h. At 10 μM concentration or higher, SFN decreased cell viability, increased the%early apoptotic cells and increased caspase 3 activity. At these higher doses, SFN increased ROS levels, which correlated with apoptotic endpoints and cell viability decline. In exposed cells, gene expression analysis revealed only partial induction of phase-2 detoxification genes. More importantly, SFN inhibited ROS-scavenging enzymes and impaired glutathione recycling, as evidenced by inhibition of glutathione reductase (GR) activity and combined inhibition of glutathione peroxidase (GPx) gene expression and enzyme activity. In conclusion, SFN induced oxidative stress and apoptosis via a p53-independent mechanism. GPx expression and activity were found associated with ROS accumulation in MG-63 cells and are potential biomarkers for the efficacy of ROS-inducing agents e.g. as co-adjuvant drugs in osteosarcoma

Analysis of longitudinal nef sequence variation throughout HIV-2 infection

Abstract publicado em: International Journal of Infectious Diseases. 2010;14(Supl 1).Background: Human Immunodeficiency Virus type 1 (HIV-1) and type 2 (HIV-2) may case a severe immunodeficiency in humans (AIDS). However HIV-2 is more frequently associated with lower levels of transmission and disease progression, compared with HIV-1 infections. The role of nef gene in vivo during the development of AIDS has been clearly demonstrated in simian immunodeficiency virus infected Rhesus macaques model, but the determinants which play a role in the pathogenesis of HIV are relatively poorly understood. However, even less is known about the role of nef in HIV-2 infections. Methods: In this study, it was analyzed the variation of 48 nef gene sequences, obtained from samples taken between 1994 and 2009, corresponding to 17 HIV-2-infected individuals with different clinical stages of infection. The sequences obtained by Nested PCR were classified by phylogenetic analysis and the functional protein motifs, described as important in CD4 and MHC-I downregulation and in viral infectivity were also analyzed. Results: In all individuals were identified nef sequences from group A of HIV-2, which encoded possible functional and complete protein. There was a greater conservation of residues in the Nef sequences of individuals in the symptomatic stage (63%), comparatively to individuals in the asymptomatic stage (19%). While some functional motifs (MGxxxS1, DDDD93, RR137 and DD205) and also residues (G128, I141 and L142) remained conserved, others (YSRF39, LRAR21, PxxP101, EE185) revealed changes during the follow-up period. The PxxP motif exhibited wide inter-individual variation in vivo from an HIV-1-like tetra-proline motif (PxxP)3 to disruption of the minimal core PxxPLR motif. The disruption was observed in 11 sequences exclusively from asymptomatic individuals (p=0.021). The sequence motif variation towards tetra-proline configuration was observed in 2 symptomatic individuals during time of infection. The results also revealed the existence of a negative selective pressure, as well as codons under positive pressure in the sequences. Conclusion: In this HIV-2-infected individuals studied, it was observed a need for a greater degree of Nef protein conservation in a symptomatic phase. Sequences altered and potentially critical for the Nef function in vivo, in earlier stages of infection, may contribute at some level to a different pattern in viral pathogenesis and disease progression

High pressure studies on bis(L-histidinate)nickel(II) monohydrate

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNCAP - FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICORaman spectra of bis (L-histidinate)nickel(11) monohydrate crystal were obtained for pressures up to 9.5 GPa. Our results show the disappearance of some of the Raman modes and the appearance of other modes. These modifications evidence that the sample undergoes phase transitions at around 0.8 and 3.2 GPa. The role played by the Ni ions and hydrogen bonds in the dynamics of the phase transitions is discussed. Under decompression, down to atmospheric pressure, the original Raman spectra are recovered, showing that both phase transitions are fully reversible.189258264CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNCAP - FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNCAP - FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO454941/2014-501/201