Search

The electron-transfer flavoprotein dehydrogenase gene (ETFDH) encodes the ETF-ubiquinone oxidoreductase (ETF-QO) and has been reported to be the major cause of multiple acyl-CoA dehydrogenase deficiency (MADD). In this study, we present the clinical and molecular diagnostic challenges, at the DNA and RNA levels, involved in establishing the genotype of four MADD patients with novel ETFDH variants: a missense variant, two deep intronic variants and a gross deletion. RNA sequencing allowed the identification of the second causative allele in all studied patients. Simultaneous DNA and RNA investigation can increase the number of MADD patients that can be confirmed following the suggestive data results of an expanded newborn screening program. In clinical practice, accurate identification of pathogenic mutations is fundamental, particularly with regard to diagnostic, prognostic, therapeutic and ethical issues. Our study highlights the importance of RNA studies for a definitive molecular diagnosis of MADD patients, expands the background of ETFDH mutations and will be important in providing an accurate genetic counseling and a prenatal diagnosis for the affected families.

Background The impairment of the hepatic enzyme phenylalanine hydroxylase (PAH) causes elevation of phenylalanine levels in blood and other body fluids resulting in the most common inborn error of amino acid metabolism (phenylketonuria). Persistently high levels of phenylalanine lead to irreversible damage to the nervous system. Therefore, early diagnosis of the affected individuals is important, as it can prevent clinical manifestations of the disease. Methods In this report, the biochemical and genetic findings performed in 223 patients diagnosed through the Portuguese Neonatal Screening Program (PNSP) are presented. Results Overall, the results show that a high overlap exists between different types of variants and phenylalanine levels. Molecular analyses reveal a wide mutational spectrum in our population with a total of 56 previously reported variants, most of them found in compound heterozygosity (74% of the patients). Intragenic polymorphic markers were used to assess the haplotypic structure of mutated chromosomes for the most frequent variants found in homozygosity in our population (p.Ile65Thr, p.Arg158Gln, p.Leu249Phe, p.Arg261Gln, p.Val388Met, and c.1066‐11G>A). Conclusion Our data reveal high heterogeneity at the biochemical and molecular levels and are expected to provide a better understanding of the molecular basis of this disease and to provide clues to elucidate genotype–phenotype correlations., The present study identify and characterize the variants underlying PKU in affected individuals in the Portuguese PKU/HPA cohort. Biochemical data, haplotic analysis and genetic findings performed in 223 patients diagnosed through the Portuguese Neonatal Screening Program (PNSP) is presented. The information obtained will improve the diagnostic applicability of mutational analysis and the capacity to predict the evolution of the disease.

Glutaric aciduria type 1 (GA-1) is a rare but treatable inherited disease caused by deficiency of glutaryl-CoA dehydrogenase activity due to GCDH gene mutations. In this study, we report 24 symptomatic GA-1 Brazilian patients, and present their clinical, biochemical, and molecular findings. Patients were diagnosed by high levels of glutaric and/or 3-hydroxyglutaric and glutarylcarnitine. Diagnosis was confirmed by genetic analysis. Most patients had the early-onset severe form of the disease and the main features were neurological deterioration, seizures and dystonia, usually following an episode of metabolic decompensation. Despite the early symptomatology, diagnosis took a long time for most patients. We identified 13 variants in the GCDH gene, four of them were novel: c.91 + 5G > A, c.167T > G, c.257C > T, and c.10A > T. The most common mutation was c.1204C > T (p.R402W). Surprisingly, the second most frequent mutation was the new mutation c.91 + 5G > A (IVS1 ds G-A + 5). Our results allowed a complete characterization of the GA-1 Brazilian patients. Besides, they expand the mutational spectrum of GA-1, with the description of four new mutations. This work reinforces the importance of awareness of GA-1 among doctors in order to allow early diagnosis and treatment in countries like Brazil where the disease has not been included in newborn screening programs. info:eu-repo/semantics/publishedVersion

The non-specific immunity can induce iron deprivation as a defense mechanism against potential bacterial pathogens, but little information is available as to its role in Antarctic fish. In this study the response of iron metabolism related genes was evaluated in liver and head kidney of the Antarctic notothenoids Notothenia coriiceps and Notothenia rossii 7 days after lipopolysaccharide (LPS) injection. Average plasma Fe2+ concentration was unaffected by treatment in any of the species. The gene expression response to LPS varied between tissues and species, being stronger in N. coriiceps and more prominent in the head kidney than liver. The reaction to LPS was marked by increased individual variability in most genes analyzed, even when the change in expression was not statistically significant, suggesting different individual sensitivity and coping responses in these wild fish. We found that iron related genes had an attenuated and homogenous response to LPS but there was no detectable relationship between plasma Fe2+ and gene expression. However, overall in both tissues and species LPS exposure set a multilevel response that concur to promote intracellular accumulation of iron, an indication that Antarctic Notothenoids use innate nutritional immunity as a resistance mechanism against pathogens. FCT-NSFC/0002/2016; CCMAR/Multi/04326/2013; PTDC/BIAANM/3484/2014 info:eu-repo/semantics/publishedVersion

Investigation of the excited state decay dynamics of transition metal systems is a crucial step for the development of photoswitchable molecular based ma- terials with applications in growing fields as energy conversion, data storage or molecular devices. The photophysics of these systems is an entangled problem arising from the interplay of electronic and geometrical rearrangements that take place on a short time scale. Several factors play a role in the process: various electronic states of di↵erent spin and chemical character are involved, the system undergoes important structural variations and several nonradiative processes can occur. Computational chemistry is a useful tool to get insight into the micro- scopic description of the photophysics of these materials since it provides unique information about the character of the electronic spin states involved, the ener- getics and time evolution of the system. In this review article, we present an overview of the state of the art methodologies available to address the several aspects that have to be incorporated to properly describe the deactivation of excited states in transition metal complexes. The most recent developments in theoretical methods are discussed and illustrated with examples.

Core level binding energies, directly measured by X-ray photoelectron spectroscopy (XPS), provide unique information regarding the chemical environment of atoms in a given system. However, interpretation of XPS in extended systems may not be straightforward and requires assistance from theory. The different state-of-the-art theoretical methods commonly used to approach core level binding energies and their shifts with respect to a given reference are reviewed and critically assessed with special emphasis on recently developed theoretical methods and with a focus on future applications in materials and surface sciences.

Spin-orbit couplings have been calculated in twenty snapshots of a molecular dynamics trajectory of [Fe(bpy)3]2+ to address the importance of geometrical distortions and second-order spin-orbit coupling on the intersystem crossing rate constants in the light-induced spin crossover process. It was found that the effective spin-orbit coupling between the 3MLCT and 5T2 state is much larger than the direct coupling in the symmetric structure, which opens the possibility of a direct 3MLCT-5T2 deactivation without the intervention of triplet metal-centered states. Based on the calculated deactivation times, we conclude that both the direct path- way and the one involving intermediate triplet states are active in the ultrafast population of the metastable HS state, bringing in agreement two experimental observations that advocate for either deactivation mechanism. This resolves a long-standing dispute about the deactivation mechanism of Fe(II)-polypyridyl complexes in particular, and about light-induced magnetism in transition metal complexes in general.

The neuropeptide galanin (Gal) is a putative factor regulating puberty onset and reproduction through its actions on the pituitary. The present study investigated the pituitary responsiveness to galanin and the patterns of galanin receptors (Galrs) expression throughout the reproductive cycle of two years old male European sea bass (Dicentrarchus labrax), an important aquaculture species. Quantitative analysis of pituitary and hypothalamus transcript expression of four galr subtypes revealed differential regulation according to the testicular developmental stage, with an overall decrease in expression from the immature stage to the mid-recrudescence stage. Incubation of pituitary cells with mammalian 1–29 Gal peptide induced significant changes in cAMP concentration, with sensitivities that varied according to the testicular development stages. Furthermore 1–29 Gal was able to stimulate both follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) release from pituitary cell suspensions. The magnitude of the effects and effective concentrations varied according to reproductive stage, with generalized induction of Fsh and Lh release in animals sampled in January (full spermiation). The differential expression of galrs in pituitary and hypothalamus across the reproductive season, together with the differential effects of Gal on gonadotropins release in vitro strongly suggests the involvement of the galaninergic system in the regulation the hypothalamus-pituitary-gonad axis of male sea bass. This is to our knowledge the first clear evidence for the involvement of galanin in the regulation of reproduction in non-mammalian vertebrates., This work was supported by the Portuguese Foundation for Science and Technology [grant numbers SFRH/BPD/84033/2012, PTDC/MAR-BIO/3890/2012, UID/Multi/04326/2013]; the European Union Seventh Framework Programme [AQUAEXCEL grant number 262336]; the Spanish Ministry of Science and Innovation (MICINN) and the Spanish Ministry of the Economy and Competitiveness (MINECO) [KISSCONTROL project, AGL2009-11086]; the Spanish Ministry of the Economy and Competitiveness and the Regional Government of Valencia (REPROBASS project, PROMETEOII/2014/051).

We use a total energy difference approach to explore the ability of various density functional theory based methods in accounting for the differential effect of static electron correlation on the C(1s) and O(1s) core level binding energies (BEs) of the CO molecule. In particular, we focus on the magnitude of the errors of the computed C(1s) and O(1s) BEs and on their relative difference as compared to experiment and to previous results from explicitly correlated wave functions. Results show that the different exchange-correlation functionals studied here behave rather erratically and a considerable number of them lead to large errors in the BEs and/or the BE shifts. Nevertheless, the TPSS functional, its TPSSm and RevTPSS derivations, and its corresponding hybrid counterpart, TPSSh, perform better than average and provide BEs and BE shifts in good agreement with experiment.

Objective Birth prevalence of Cobalamin (Cbl) C or D defects in Portugal is an estimated 1:85,000, one of the highest worldwide. We compared the genotype/phenotype of patients identified with CblC or CblD before and after the implementation of expanded newborn screening. Methods Twenty-five Portuguese CblC/D patients, 14 symptomatic and 11 identified through screening, were diagnosed using gas chromatography or tandem mass spectrometry. Molecular characterization was performed through the study of MMACHC and MMADHC genes. Results The most common MMACHC mutation, c.271dupA, was present in 100% of MMACHC alleles of all CblC screened patients, in contrast with the 61% identified before expanded newborn screening. All studied cases (except one, who presented a CblD deficiency) presented a CblC defect. More CblC late-onset patients were diagnosed before the introduction of newborn screening than in the post newborn screening era, probably because some early onset patients died without a definitive diagnosis. Conclusion The molecular data found in this cohort contribute to the improvement of screening and diagnosis of Cbl defects and would enable a confirmatory diagnosis of these patients, reducing the need for complex, costly, laborious, and time-consuming biochemical/enzymatic tests.

10.1039/c3dt52027g The spin crossover behavior of the two [Fe(mtz)6](2+) complexes occupying different lattice sites in Fe(mtz)6(BF4)2 is addressed by combining quantum chemical calculations with a careful analysis of the crystal structure. It is first established from the calculations that the energy difference between high spin and low spin states depends on the orientation of the tetrazole ligands; small rotation angles favor the low spin state, while for angles larger than ~20° the high spin state is more stable. The crystal structure shows that the two complexes have different average rotation angles of the ligands. It is larger for the site that remains HS down to low temperatures and smaller for the site that shows spin crossover to LS. The origin of the different rotation angles is found to be determined by a subtle interplay amongst steric repulsion between the ligands, HF interactions between the complex and the counterions, and intersite interactions involving NH contacts and p-p interactions between the N[double bond, length as m-dash]N double bonds of the tetrazole rings.

Theoretical methods together with appropriate surface models are capable of treating very large oxide systems with an increasing predictive power, especially for the ground-state properties and chemical reactivity. In any case, the progress in CI (configuration interaction) methods specially designed to reproduce excitation energies, such as difference-dedicated configuration interaction (DDCI), together with the remarkable advances in DFT and TD-DFT methods, which are nowadays applicable to cluster or periodic surface models, has paved the way for the study of more realistic systems. The modeling of dye-sensitized solar cells (DSSCs) where the oxide surface, the adsorbed dye, and the effect of the solvent are all taken into account simultaneously to predict the absorption spectrum of the corresponding system constitute no doubt a landmark toward the theoretically assisted prediction and engineering of more efficient DSSCs

We explore the excited state energy landscape of small polyhedral zinc sulfide clusters (Zn(4)S(4) and Zn(6)S(6)) using time-dependent density functional theory and correlated wave function based methods. We predict the optical absorption and photoluminescence spectra of the polyhedral clusters and demonstrate that, upon relaxation of the excited state, these nanostructures break symmetry and an electron and a hole localize on a small number of Zn (electron) and S (hole) centers. We further test several exchange-correlation potentials for their ability to recover the correlated wave function description of the excited state. Finally, we discuss how the degeneracy of excited states in nanostructures, such as those considered here, results in a Jahn-Teller distortion of the excited state geometry, and how numerical problems arising from this can be circumvented by starting the optimization of excited states from structures distorted along the ground state vibrational normal modes.

Aggregates of oxygen vacancies (F centers) represent a particular form of point defects in ionic crystals. In this study we have considered the combination of two oxygen vacancies, the M center, in the bulk and on the surface of MgO by means of cluster model calculations. Both neutral and charged forms of the defect M and ${M}^{+}$ have been taken into account. The ground state of the M center is characterized by the presence of two doubly occupied impurity levels in the gap of the material; in ${M}^{+}$ centers the highest level is singly occupied. For the ground-state properties we used a gradient corrected density functional theory approach. The dipole-allowed singlet-to-singlet and doublet-to-doublet electronic transitions have been determined by means of explicitly correlated multireference second-order perturbation theory calculations. These have been compared with optical transitions determined with the time-dependent density functional theory formalism. The results show that bulk M and ${M}^{+}$ centers give rise to intense absorptions at about 4.4 and 4.0 eV, respectively. Another less intense transition at 1.3 eV has also been found for the ${M}^{+}$ center. On the surface the transitions occur at 1.6 eV ${(M}^{+})$ and 2 eV (M). The results are compared with recently reported electron energy loss spectroscopy spectra on MgO thin films.

The weakly avoided crossing between the two lowest 1Σ+ electronic states of a series of alkali halide molecules has been studied by means of the recently reported multistate complete active space second-order perturbation theory, MS-CASPT2, method. For a large enough basis set and a complete active space self-consistent field that includes part of the radial and angular correlation of the outermost halide electrons, the calculated crossing distance is in very good agreement with that predicted from the Rittner empirical potential. The study of the relevant parameters corresponding to the crossing region on these molecules has been extended to include the effect of a uniform electric field and a generalization of the empirical Rittner formula that includes the electric field effects is presented. The predictions made by the MS-CASPT2 method are also in agreement with those derived from the generalized Rittner potential. Finally, the possible implications of the present work on electron transfer processes at metal electrodes are discussed.

We have determined cluster model wavefunctions to identify the origin of the trend for the chemical shifts of the core level binding energies of alkaline-earth atoms in ionic oxides with respect to bulk metals. We have identified two initial state effects, both electrostatic in nature, which fully determine the trend. The first one is the increase in the core level binding energies of the dication compared to the neutral metal atom; the second is the decrease of the dication binding energies induced by the Madelung potential of the ionic crystal. The sum of these two cancelling contributions reproduces the observed trend in chemical shifts from MgO to BaO. Chemical bonding effects, in particular the covalent interaction between the unoccupied d-levels of the dications and the oxygen anions, do not contribute in a significant way to the trend.