Lophotrochozoan neuroanatomy: An analysis of the brain and nervous system of Lineus viridis(Nemertea) using different staining techniques

<p>Abstract</p> <p>Background</p> <p>The now thriving field of neurophylogeny that links the morphology of the nervous system to early evolutionary events relies heavily on detailed descriptions of the neuronal architecture of taxa under scrutiny. While recent accounts on the nervous system of a number of animal clades such as arthropods, annelids, and molluscs are abundant, in depth studies of the neuroanatomy of nemerteans are still wanting. In this study, we used different staining techniques and confocal laser scanning microscopy to reveal the architecture of the nervous system of <it>Lineus viridis </it>with high anatomical resolution.</p> <p>Results</p> <p>In <it>L. viridis</it>, the peripheral nervous system comprises four distinct but interconnected nerve plexus. The central nervous system consists of a pair of medullary cords and a brain. The brain surrounds the proboscis and is subdivided into four voluminous lobes and a ring of commissural tracts. The brain is well developed and contains thousands of neurons. It does not reveal compartmentalized neuropils found in other animal groups with elaborate cerebral ganglia.</p> <p>Conclusions</p> <p>The detailed analysis of the nemertean nervous system presented in this study does not support any hypothesis on the phylogenetic position of Nemertea within Lophotrochozoa. Neuroanatomical characters that are described here are either common in other lophotrochozoan taxa or are seemingly restricted to nemerteans. Since detailed descriptions of the nervous system of adults in other nemertean species have not been available so far, this study may serve as a basis for future studies that might add data to the unsettled question of the nemertean ground pattern and the position of this taxon within the phylogenetic tree.</p

O impacto da saúde intestinal na Ansiedade: uma abordagem funcional

Introdução: O equilíbrio da microbiota intestinal é essencial para a homeostase da saúde do hospedeiro. Quando ocorre alteração na diversidade ou densidade da população de microrganismos pode ocorrer desregulação da microbiota e instala-se um quadro de disbiose. Estudos recentes abordam a associação entre a microbiota intestinal e diferentes sistemas biológicos, dentre eles estuda-se o impacto no sistema nervoso central. Objetivo:&nbsp; identificar a relação da saúde intestinal na ansiedade e descrever os manejos da nutrição clínica funcional. Metodologia: Revisão narrativa de literatura realizada nas bases de dados National Library of Medicine (MEDLINE), Web of Science e Scientific Eletronic Library Online (SciELO), no período entre 2012-2022 utilizando os seguintes descritores: ansiedade, disbiose, microbiota intestinal, nutrição, compostos bioativos. Resultados: Estudos demonstraram que a suplementação de glutamina diminui os sintomas associados à disbiose e melhorou a permeabilidade intestinal. Com a redução dos FODMAPS foi evidenciado a melhora nos sintomas intestinais. Os prebióticos e probióticos mostraram-se fundamentais no aumento do número de atividade das bactérias intestinais, facilitando o processo digestivo, além de fortalecer o sistema imunológico. As evidências apontam que a dieta mediterrânea auxilia na microbiota intestinal, aumentando a concentração de ácidos graxos de cadeia curta, contribuindo para melhora nos sintomas de disbiose, e consequentemente, no quadro de ansiedade. Conclusão: As condutas nutricionais abordadas demonstram uma relação entre a dieta, a saúde intestinal e conseguinte nos sintomas de ansiedade, porém faz-se necessário que mais estudos relacionados especificamente ao tema da saúde mental sejam realizados para auxiliar o tratamento dietoterápico nessas situações

Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary

<p>Abstract</p> <p>Background</p> <p>Invertebrate nervous systems are highly disparate between different taxa. This is reflected in the terminology used to describe them, which is very rich and often confusing. Even very general terms such as 'brain', 'nerve', and 'eye' have been used in various ways in the different animal groups, but no consensus on the exact meaning exists. This impedes our understanding of the architecture of the invertebrate nervous system in general and of evolutionary transformations of nervous system characters between different taxa.</p> <p>Results</p> <p>We provide a glossary of invertebrate neuroanatomical terms with a precise and consistent terminology, taxon-independent and free of homology assumptions. This terminology is intended to form a basis for new morphological descriptions. A total of 47 terms are defined. Each entry consists of a definition, discouraged terms, and a background/comment section.</p> <p>Conclusions</p> <p>The use of our revised neuroanatomical terminology in any new descriptions of the anatomy of invertebrate nervous systems will improve the comparability of this organ system and its substructures between the various taxa, and finally even lead to better and more robust homology hypotheses.</p

Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

The $B_s^0\to J/\psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$\beta$ measurement from $B^0\to J/\psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}$. This is the most precise measurement to date

Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201

Intrinsic Determinants of Aβ12–24 pH-Dependent Self-Assembly Revealed by Combined Computational and Experimental Studies

The propensity of amyloid- (A) peptide to self-assemble into highly ordered amyloid structures lies at the core of their accumulation in the brain during Alzheimer's disease. By using all-atom explicit solvent replica exchange molecular dynamics simulations, we elucidated at the atomic level the intrinsic determinants of the pH-dependent dimerization of the central hydrophobic segment A and related these with the propensity to form amyloid fibrils measured by experimental tools such as atomic force microscopy and fluorescence. The process of A dimerization was evaluated in terms of free energy landscape, side-chain two-dimensional contact probability maps, -sheet registries, potential mean force as a function of inter-chain distances, secondary structure development and radial solvation distributions. We showed that dimerization is a key event in A amyloid formation; it is highly prompted in the order of pH 5.02.98.4 and determines further amyloid growth. The dimerization is governed by a dynamic interplay of hydrophobic, electrostatic and solvation interactions permitting some variability of -sheets at each pH. These results provide atomistic insight into the complex process of molecular recognition detrimental for amyloid growth and pave the way for better understanding of the molecular basis of amyloid diseases

Measurement of the CP-violating phase β\beta in B0→J/ψπ+π−B^0\rightarrow J/\psi \pi^+\pi^- decays and limits on penguin effects

Time-dependent CP violation is measured in the $B^0\rightarrow J/\psi\pi^+\pi^-$ channel for each $\pi^+\pi^-$ resonant final state using data collected with an integrated luminosity of 3.0 fb$^{-1}$ in $pp$ collisions using the LHCb detector. The final state with the largest rate, $J/\psi\rho^0(770)$, is used to measure the CP-violating angle $2\beta^{\rm eff}$ to be $(41.7\pm 9.6_{-6.3}^{+2.8})^{\circ}$. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, $B_s^0\rightarrow J/\psi\phi$ decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase $\phi_s$ is limited to be within the interval [$-1.05^\circ$, +$1.18^\circ$] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.Comment: 18 pages, 6 figures; v2-updated from reviewers comments and added a figur

Measurement of CP violation parameters and polarisation fractions in Bs0→J/ψK‾∗0 {\mathrm{B}}_{\mathrm{s}}^0\to \mathrm{J}/\psi {\overline{\mathrm{K}}}^{\ast 0} decays

The first measurement of ${C\!P}$ asymmetries in the decay ${B_s^0\to J/\psi \overline{K}^{*}(892)^{0}}$ and an updated measurement of its branching fraction and polarisation fractions are presented. The results are obtained using data corresponding to an integrated luminosity of $3.0\,fb^{-1}$ of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of $7$ and $8\,\mathrm{TeV}$. Together with constraints from ${B^0\to J/\psi \rho^0}$, the results are used to constrain additional contributions due to penguin diagrams in the ${C\!P}$-violating phase ${{\phi}_{s}}$, measured through ${B_s^0}$ decays to charmonium.Comment: 39 pages, 7 tables, 8 figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-034.htm

Comparative neuroanatomy of Mollusks and Nemerteans in the context of deep metazoan phylogeny

Despite the plenty of molecular phylogenetic studies that emerged in recent years the position of major animal clades within the phylogenetic tree is still controversial. Therefore, the field of neurophylogeny that links the morphology of the nervous system to early evolutionary events emerged as a discipline that can be helpful for the inference of phylogenetic relationships as well as for the retracing of central nervous system evolution. So far, comparative neuroanatomical investigations in arthropods and annelids have suggested that certain brain centers are highly conserved during evolution. If structures like the mushroom bodies are indeed ancestral features of the bilaterian brain, we would expect to find similar neuropils in other invertebrate phyla as well. However, so far in depth studies of the detailed neuroanatomy of numerous invertebrate taxa are lacking. The present thesis therefore focuses on adding new comparative immunohistochemical data on the nervous system of the two lophotrochozoan phyla Mollusca and Nemertea. The first part of the thesis presents an extensive survey on the detailed neuroanatomy of the lesser-known branches of the phylum Mollusca: Caudofoveata, Solenogastres, Polyplacophora, and Scaphopoda. By comparing the neuroanatomy of those different taxa it is demonstrated that the presence of two pairs of nerve cords of the medullary type is the main unifying feature of the three non-conchiferan taxa. In other respects, the great diversity of the phylum Mollusca likewise results in a considerable variability of the nervous system. Taking the results of both aplacophoran taxa, the brain as well as the nerve cords of Caudofoveata and Solenogastres are built in a conspicuous different manner. Structures that are similar in the nervous system of Caudofoveata and Solenogastres are as well present in the Polyplacophora. Thus a monophyly of Aplacophora could not be confirmed. Comparing the nervous system of the Caudofoveata, Solenogastres, and Polyplacophora, the caudofoveate brain seems to be most complex among the non-conchiferan taxa because it exclusively shows a division into discrete sections. The neuroanatomical data presented here, are therefore not in accordance with the Adenopoda hypothesis placing Caudofoveata basal within Mollusca. The second part of the present thesis concentrates on the neuroanatomy of one representative of the phylum Nemertea. The nervous system of Lineus viridis basically consists of a well developed brain that reveals no compartmentalized neuropils. Paired medullary cords emanate posteriorly from the ventral lobes of the brain while paired cerebral organs are posteriorly attached to the dorsal lobes of the brain. By presenting a detailed view on the peripheral nervous system as well, this study reveals that nemerteans possess four distinct but interconnected nerve plexus. The results indicate that a subepidermal plexus most likely belongs to the ground pattern of Lophotrochozoa. Higher brain centers like the mushroom bodies that are typical for the arthropod and annelid brain could not been identified neither in the investigated molluscan taxa nor in the nemertean species. However, the nervous system of the investigated caudofoveate, scaphopod, and nemertean species exhibit clusters of cells resembling the globuli cells that characterize the arthropod and annelid mushroom body. Those globuli-like cell clusters are located in the precerebral ganglia of caudofoveates and the cerebral organs of nemerteans, respectively. Like the mushroom bodies of arthropods and annelids the precerebral ganglia as well as the cerebral organs are involved in the processing of olfactory information. Assuming that these cell clusters are indeed homologous, the present findings argue for the existence of mushroom body-like precursor structures in the last common ancestor of all protostomes. Besides the contribution to the evolution of certain brain centers in protostomes, the neuroanatomical data obtained in the present study are used for the construction of a data matrix that will result in a phylogenetic tree that is exclusively based on neuroanatomical data