Riccati-type equations, generalised WZNW equations, and multidimensional Toda systems

We associate to an arbitrary $\mathbb Z$-gradation of the Lie algebra of a Lie group a system of Riccati-type first order differential equations. The particular cases under consideration are the ordinary Riccati and the matrix Riccati equations. The multidimensional extension of these equations is given. The generalisation of the associated Redheffer--Reid differential systems appears in a natural way. The connection between the Toda systems and the Riccati-type equations in lower and higher dimensions is established. Within this context the integrability problem for those equations is studied. As an illustration, some examples of the integrable multidimensional Riccati-type equations related to the maximally nonabelian Toda systems are given.Comment: LaTeX2e, 18 page

The complex Sine-Gordon equation as a symmetry flow of the AKNS Hierarchy

It is shown how the complex sine-Gordon equation arises as a symmetry flow of the AKNS hierarchy. The AKNS hierarchy is extended by the ``negative'' symmetry flows forming the Borel loop algebra. The complex sine-Gordon and the vector Nonlinear Schrodinger equations appear as lowest negative and second positive flows within the extended hierarchy. This is fully analogous to the well-known connection between the sine-Gordon and mKdV equations within the extended mKdV hierarchy. A general formalism for a Toda-like symmetry occupying the ``negative'' sector of sl(N) constrained KP hierarchy and giving rise to the negative Borel sl(N) loop algebra is indicated.Comment: 8 pages, LaTeX, typos corrected, references update

Transcriptomic analysis of plasmid and plasmid-related chromosomal ORFs in C. trachomatis strains with different cell-appetence

Despite the undergoing chromosomal size-reduction of Chlamydia trachomatis, almost all strains maintain the conserved 7,5kb plasmid. It has been recently considered a virulence factor, as plasmid-bearing strains evidenced a higher ability to successfully colonize epithelial cells and sustain infection than plasmidless strains. However, the biological role of the eight plasmid ORFs remains poorly characterized. Thus, we aim to correlate the relative expression of each plasmid ORFs with the number of plasmids per genome as well as with the relative expression of chromosomal genes that seem to be regulated by the plasmid, during the whole Chlamydia developmental cycle. Both the transcriptomic analysis of all the selected ORFs and the determination of the plasmid copy number were performed by qPCR in prototype and currently circulating strains with distinct cell-appetence and ecological success, throughout Chlamydia developmental cycle. So far, our results indicate: 1) huge differences (up to 100-fold) in the expression levels between plasmid ORFs; 2) for the same ORF, different expression levels and profiles among strains; 3) variation in the number of plasmids per genome during the infectious cycle; 4) the higher expression level of the plasmid ORFs do not seem to correlate with a higher number of plasmids per genome. These results, together with our ongoing transcriptomic survey of the plasmid-related chromosomal genes, will contribute to shed some light on the molecular function of the plasmid ORFs in chlamydial biology

Influência da quantidade de ração sobre o desempenho reprodutivo de leitoas do primeiro o terceiro cio.

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Molecular features underlying the higher ecological success of C. trachomatis E and F genotypes

In the light of the >98% genomic similarity among Chlamydia trachomatis serovars, the higher worldwide ecological success of E and F is enigmatic. We intend to provide a quick overview of the molecular data that distinguish these from the remaining strains. Examples are: - E and F possess a similar chromosomal genetic make-up distinct from the remaining genotypes. Some loci linked to this independent co-segregation comprehend membrane proteins, hypothetical virulence factors, and regulatory regions (published data). - Some loci reveal nonrandom mutational patterns, where mutations exclusive of E and F are clustered in specific protein domains, likely promoting strains functional and/or structural attributes (published data). - Based on data from a worldwide survey, MOMP of E and F exhibit the lowest mutation rate (22.3-fold lower), implying more fitted antigenic profiles to deal with host immunity (published data). - The likelihood of E and F strains to undergo genetic recombination is about 12-fold lower than that of the other genotypes (P<10-2), suggesting a putative clonal evolution, where superimposed favorable clones may be strongly maintained in vivo (preliminary data from our lab). - Strains E and F do not seem to originate higher infectious load in vivo, when compared with other genital genotypes (published data). Full-genomic data from multiple and diverse clinical isolates will be essential to decipher the secret behind the higher ecological success of E and F strains

Single-cell functional and chemosensitive profiling of combinatorial colorectal therapy in zebrafish xenografts.

Cancer is as unique as the person fighting it. With the exception of a few biomarker-driven therapies, patients go through rounds of trial-and-error approaches to find the best treatment. Using patient-derived cell lines, we show that zebrafish larvae xenotransplants constitute a fast and highly sensitive in vivo model for differential therapy response, with resolution to reveal intratumor functional cancer heterogeneity. We screened international colorectal cancer therapeutic guidelines and determined distinct functional tumor behaviors (proliferation, metastasis, and angiogenesis) and differential sensitivities to standard therapy. We observed a general higher sensitivity to FOLFIRI [5-fluorouracil(FU)+irinotecan+folinic acid] than to FOLFOX (5-FU+oxaliplatin+folinic acid), not only between isogenic tumors but also within the same tumor. We directly compared zebrafish xenografts with mouse xenografts and show that relative sensitivities obtained in zebrafish are maintained in the rodent model. Our data also illustrate how KRAS mutations can provide proliferation advantages in relation to KRASWT and how chemotherapy can unbalance this advantage, selecting for a minor clone resistant to chemotherapy. Zebrafish xenografts provide remarkable resolution to measure Cetuximab sensitivity. Finally, we demonstrate the feasibility of using primary patient samples to generate zebrafish patient-derived xenografts (zPDX) and provide proof-of-concept experiments that compare response to chemotherapy and biological therapies between patients and zPDX. Altogether, our results suggest that zebrafish larvae xenografts constitute a promising fast assay for precision medicine, bridging the gap between genotype and phenotype in an in vivo setting.info:eu-repo/semantics/publishedVersio

In silico scrutiny of genes revealing phylogenetic congruence with clinical prevalence or tropism properties of Chlamydia trachomatis strains

Microbes possess a multiplicity of virulence factors that confer them the ability to specifically infect distinct biological niches. Contrary to what is known for other bacteria, for the obligate intracellular human pathogen Chlamydia trachomatis, the knowledge of the molecular basis underlying serovars’ tissue specificity is scarce. We examined all ~900 genes to evaluate the association between individual phylogenies and cell-appetence or ecological success of C. trachomatis strains. Only ~1% of the genes presented a tree topology showing the segregation of all three disease groups (ocular, urogenital, and lymphatic) into three wellsupported clades. Approximately 28% of the genes, which include the majority of the genes encoding putative type III secretion system effectors and Inc proteins, present a phylogenetic tree where only lymphogranuloma venereum strains form a clade. Similarly, an exclusive phylogenetic segregation of the most prevalent genital serovars was observed for 61 proteins. Curiously, these serovars are phylogenetically cosegregated with the lymphogranuloma venereum serovars for ~20% of the genes. Some clade-specific pseudogenes were identified (novel findings include the conserved hypothetical protein CT037 and the predicted a-hemolysin CT473), suggesting their putative expendability for the infection of particular niches. Approximately 3.5% of the genes revealed a significant overrepresentation of nonsynonymous mutations, and the majority encode proteins that directly interact with the host. Overall, this in silico scrutiny of genes whose phylogeny is congruent with clinical prevalence or tissue specificity of C. trachomatis strains may constitute an important database of putative targets for future functional studies to evaluate their biological role in chlamydial infections.This work was supported by a grant, ERA-PTG/0004/2010, from Fundação para a Ciência e a Tecnologia (FCT) (to J.P.G.), in the frame of ERA-NET PathoGenoMics. A.N. is recipient of a FCT post-doctoral fellowship (SFRH/BPD/75295/2010), V.B. and R.F. are recipients of Ph.D. fellowships (SFRH/BD/68527/2010 and SFRH/BD/68532/2010, respectively) from FCT, and V.D. is a recipient of fellowship on behalf of the grant ERA-PTG/0004/2010

Carbon stocks and pools in relation to the texture of kaolinitic soils from the Brazilian East Coast.

Extremely kaolinitic soils of Tertiary age elevations on the Brazilian east coast present a wide range of texture, which is recognized as one of the main factors controlling the soil organic matter contents. This study aimed to investigate the organic C storage of different compartments of kaolinitic soils. The studied soils had a wide particle size gradient, were under native forest vegetation, and located on Brazil?s eastern coast (Coruripe - CF, Umbaúba - UF, Nova Viçosa - VF, Sooretama - SF, and Itaboraí - IF). The forest cover of all sites allows to record soil properties reference values for a land use condition closer to that of the original sites. We determined soil organic C (SOC) content and SOC stock up to a depth of 1 m, C of topsoil (0.00-0.08 m), aggregate size classes, and dissolved organic carbon (DOC) of the soil surface horizon (A horizon). Soil C stocks at the 0.00-1.00 m depth ranged from 105 to 137 Mg ha-1 and were not regulated by soil texture. The SF soils stored more C up to a depth of 1 m, while lower mean C stocks were found for UF and CF soils. Soil texture was not a reliable index to predict the C contents of the aggregate size classes of the 0.00-0.08 m layer (within each class and in total, using equivalent soil mass of the classes). The most clayey soils had a high percentage of 2-4 mm aggregates and, as a consequence, high aggregate stability indices, which are positively correlated to silt plus clay contents of the soil surface horizon. The proportion of DOC in relation to the total organic C of the surface soil horizon was high for IF and UF areas, which are the less preserved forest fragments among all studied fragments

Anatomia de algumas ocorrências de gemas e seu enquadramento em protocolos de ordenamento territorial – contributo para uma reflexão sobre o estatuto dos depósitos gemíferos portugueses

[Abstract] Anatomy and Classification of Portuguese Gemstone Deposits and their inclusion in Territorial Management Protocols - The concept of gemstone resources includes the consideration of aspects such as the genetic type of deposits, geographical location and geological characterization of the ores. Based on archeological evidences and assuming the geological potentiality it is possible to consider the existence of resources base with gem quality, in Portugal. The main deposits are related to residual granite systems. In order to ensure a sustainable use, economical or patrimonial, it is necessary to classify these occurrences in a context of land management. This paper presents the typology of the most interesting occurrences considering its economical and patrimonial potentiality

Propriedades Métricas da Escala Aachen Aphasia Test

No contexto atual do exercício da profissão de enfermagem, com exigência crescente a nível de eficácia, eficiência e prática baseada na evidência, torna-se imperativa a utilização de instrumentos de avaliação e medida, devidamente validados para as populações que assistem e avaliam. O objetivo deste estudo foi conhecer as propriedades métricas da escala Aachen Aphasia Test (AAT), aplicada a pessoas que sofreram um Acidente Vascular Cerebral (AVC). Foi realizada uma revisão sistemática da literatura, através de bases de dados eletrónicas, nos últimos 5 anos. Selecionaram-se 4 artigos que cumpriam os critérios, relacionados com a temática. Pouca informação foi obtida relacionada com as propriedades métricas da AAT. Apenas um dos artigos aborda informações exatas e referentes às propriedades métricas da sua adaptação para a versão Portuguesa, que de acordo com os autores consultados são robustas, comparáveis às da versão Alemã. Os restantes estudos recorrem a este instrumento como padrão na comparação com outros instrumentos