Evaluating the role of the Hippo pathway in the onset and disease progression of the SOD1 mouse model of amyotrophic lateral sclerosis

The Hippo pathway is a cell signaling pathway involved in organ size regulation and tumorigenesis in mammals. This pathway regulates the activity of Yes-associated protein (YAP), a transcriptional coactivator which binds to the transcription factor TEAD to promote expression of genes controlling growth and proliferation of tissues, as well as inhibition of apoptosis. The Hippo pathway has recently been implicated as a pathogenic mechanism in neurodegenerative disorders. Specifically, mammalian sterile 20 (Ste20)-like kinase 1 (MST1), a protein kinase in the Hippo pathway, has been found to promote neuronal death under conditions of oxidative stress. Moreover, homozygous deletion of MST1 in a mouse model of Amyotrophic Lateral Sclerosis (ALS) significantly delayed onset of neurodegenerative symptoms. We examined the expression levels of key Hippo pathway components in cortex, lumbar spinal cord, and gastrocnemius muscle samples of male and female G39A SOD1 mice using western blots. Our results revealed a significant increase in phosphorylated MST1 (pMST1) in lumbar spinal cord of presymptomatic transgenic animals, and found this increase to be sex and gene copy number dependent. These results suggest that the Hippo pathway is dysregulated in the SOD1 mouse model and that MST1 may play a critical role in pathogenesis and disease progression in ALS

Expressão heteróloga de uma trans-sialidase de Trypanosoma cruzi por Trypanosoma rangeli

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Biologia.O Trypanosoma rangeli é um parasito hemoflagelado, com capacidade de infectar animais incluindo o homem, nas Américas Central e do Sul. Sua distribuição geográfica, reservatórios e vetores são compartilhados com o Trypanosoma cruzi, agente etiológico da doença de Chagas. As Trans-sialidases (TS) de T. cruzi estão relacionadas ao processo de interação, penetração do parasito na célula hospedeira e seu escape do vacúolo fagocítico. O T. rangeli possui alguns genes da família das TS, não possuindo nenhuma atividade catalítica como perfaz algumas TS de T. cruzi (TcTS). O objetivo do presente estudo foi realizar a expressão heteróloga da TcTS de T. cruzi em T. rangeli buscando a geração de uma ferramenta para estudos da interação celular patógeno-hospedeiro. Para tanto, a partir da construção plasmidial que possui o gene da TcTS de T. cruzi foi confirmada a expressão heteróloga da TcTS de T. cruzi por T. rangeli por western blot e por microscopia de fluorescência. Ainda que preliminares, foram realizados ensaios de atividade TS nos parasitos transfectados. Os resultados confirmaram a expressão heteróloga da TcTS de T. cruzi por T. rangeli, além de apontar que o parasito transfectado possui uma TS ativa.Trypanosoma rangeli is an hemoflagellate parasite, with ability to infect animals including humans, in Central and South America. Geographical distribution, reservoirs and vectors are shared with Trypanosoma cruzi, etiological agent of Chagas disease. The trans-sialidases (TS) of T. cruzi are related to the processes of interaction, penetration of the parasite in the host cell and its evasion from parasitophorus vacuole T. rangeli revealed to have genes similar to TS family members but with no catalytic activity has been proved so far, as TS of T. cruzi (TcTS). The goal of this study was to perform the heterologous expression of TcTS of T. cruzi by T. rangeli to generate a tool for the study of host-pathogen interaction. Heterologous expression of TcTS by T. rangeli was confirmed by western blot and by fluorescence microscopy using antibodies directed to the catalytic site and terminal repeats of TcTS (SAPA). Although preliminary, TS activity tests in transfected flagellate was performed. The results confirm the heterologous expression of TcTS of T. cruzi by T. rangeli, in addition to pointing out that the transfected parasite has an active TS

Osservazioni sulla Continuità Hölderiana per un Minimo di un Funzionale Convesso con Crescite Non-Standard

A result for a problem of regularity for a type of functional with not standard growths

Unveiling the photophysics of thiourea from CASPT2/CASSCF potential energy surfaces and singlet/triplet excited state molecular dynamics simulations

This work describes the decay mechanism of photoexcited thiourea, both in gas phase and in solution, from the information inferred from the topography of the excited and ground state potential energy surfaces and mixed singlet/triplet quantum classical molecular dynamics simulations. Our gas phase results reveal T1/S0 intersystem crossing as the dominant (49%) intrinsic decay channel to the ground state, which reaches a population of 0.28 at the final time of our simulations (10 ps). Population of the T1, would occur after internal conversion to the S1 from the spectroscopic S2 electronic state, followed by S1->T2 intersystem crossing and T2->T1 internal conversion processes. Minor decay channels occurring exclusively along the singlet manifold, i.e. S2->S0 (33%) and S1->S0 (18%), were also observed to play a role in the relaxation of photoexcited thiourea in the gas phase. The explicit incorporation of water-thiourea interactions in our simulations was found to provoke a very significant delay in the decay to the ground state of the system, with no transitions to the S0 being registered during the first 10 ps of our simulations. Intermolecular vibrational energy redistribution and explicit hydrogen bond interaction established between water molecules and the NH2 group of thiourea were found to structurally or energetically hamper the access to the intersystem crossing or internal conversion funnels with the ground state

An overview of nonadiabatic dynamics simulations methods, with focus on the direct approach versus the fitting of potential energy surfaces

We review state-of-the-art nonadiabatic molecular dynamics methods, with focus on the comparison of two general strategies: the "direct" one, in which the potential energy surfaces (PES) and the couplings between electronic states are computed during the integration of the dynamics equations; and the "PES-fitting" one, whereby the PES and couplings are preliminarily computed and represented as functions of the nuclear coordinates. Both quantum wavepacket dynamics (QWD) and classical trajectory approaches are considered, but we concentrate on methods for which the direct strategy is viable: among the QWD ones, we focus on those based on traveling basis functions. We present several topics in which recent progress has been made: quantum decoherence corrections in trajectory methods, the use of quasi-diabatic representations, the sampling of initial conditions and the inclusion of field-molecule interactions and of spin-orbit couplings in the dynamics. Concerning the electronic structure calculations, we discuss the use of ab initio, density functional and semiempirical methods, and their combination with molecular mechanics (QM/MM approaches). Within the semiempirical framework, we provide a concise but updated description of our own method, based on configuration interaction with floating occupation molecular orbitals. We discuss the ability of different approaches to provide observables directly comparable with experimental results and to simulate a variety of photochemical and photophysical processes. In the concluding remarks, we stress how the border between direct and PES-fitting methods is not so sharp, and we briefly discuss recent trends that go beyond this traditional distinction

Photochemistry. A modern theoretical perspective

This book offers an introduction to photochemistry for students with a minimal background in physical chemistry and molecular quantum mechanics. The focus is from a theoretical perspective and highlights excited state dynamics. The authors, experienced lecturers, describe the main concepts in photochemical and photophysical processes that are used as a basis to interpret classical steady-state experimental results (essentially product branching ratios and quantum yields) and the most advanced time-resolved techniques. A significant portion of the content is devoted to the computational techniques present in quantum chemistry and molecular dynamics. With its short summaries, questions and exercises, this book is aimed at graduate students, while its theoretical focus differentiates it from most introductory textbooks on photochemistry

Improving Guess Geminals for the Geminal Mean Field Configuration Interaction Method

The purpose of this letter is to show that a rotation of Hartree-Fock canonical orbitals which minimizes the lowest eigenvalues of a configuration interaction calculation limited to the mono-excitated configurations from a given orbital allows one to construct a better starting guess for the geminal mean field configuration interaction method

The photo-orientation of azobenzene in viscous solutions, simulated by a stochastic model

We report a computational study of the photo-orientation kinetics in a viscous solution of azobenzene in ethylene glycol, under irradiation with linearly polarized light. The development of anisotropy and its interplay with photoisomerization are simulated by a stochastic model. A distinctive feature of the model is that it takes into account the photo-orientation angular distributions, specific for each isomer, obtained by nonadiabatic dynamics simulations at the molecular level. We find that the anisotropy, as measured by optical absorption dichroism, does not necessarily increase monotonously with time. As expected, the photo-orientation turns out to be strongly coupled with photoisomerization, but the latter is not a mandatory ingredient of this phenomenon: we predict that any chromophore undergoing large amplitude geometry relaxation during its excited state dynamics can develop anisotropy under suitable conditions

Dynamics of acetone photodissociation: a surface hopping study

We present on the fly surface hopping simulations of the dynamics of photoexcited acetone in the n->pi* band, taking into account both the spin-orbit and the dynamic couplings and allowing for the C-C bond dissociation. The S0, S1, T1 and T2 states were considered and the propagation time was 50 ps. According to the simulation results, after excitation to S1 both Internal Conversion (IC) to S0 and InterSystem Crossing (ISC) to T1 or T2 take place at comparable rates; T2 plays an important role and the simultaneous treatment of the spin-orbit and dynamic couplings is shown to be mandatory to describe the photodynamics. We propose a mechanism that explains the observed fast and slow decay rates of the S1 state of acetone