Formação de classes ordinais após a aprendizagem de seqüências independentes

A aquisição de relações ordinais entre estímulos arbitrários é uma importante habilidade comportamental, requisito para a aprendizagem de comportamentos acadêmicos, especialmente a alfabetização. O propósito deste estudo foi investigar o efeito do ensino de seqüências de dois termos com sobreposição na emergência de relações ordinais com mais de dois estímulos. A sobreposição ocorre quando o último estímulo em uma seqüência de dois estímulos é o primeiro de outra seqüência (e.g., S1 -> S2 e S2 ->S3, onde S2 é o estímulo sobreposto). Nas Etapas 1 e 2 de um experimento conduzido com cinco estudantes do ensino fundamental foram ensinadas seqüências de dois termos com os cinco estímulos de um conjunto A (A1 -> A2, A2 -> A3, A3 -> A4, A4 ->A5) e os cinco de um conjunto B (B1 -> B2, B2 ->B3, B3 -> B4, B4 -> B5). Estabelecida essa linha de base, foram conduzidos testes da emergência de relações ordinais com três, quatro e cinco termos dos conjuntos A e B, separadamente. A Etapa 3 avaliou se estímulos das seqüências ensinadas eram mutuamente substituíveis, com base na mesma função ordinal (primeiro, secundo, etc.). Os estudantes compuseram as relações ordinais ensinadas e apresentaram relações ordinais emergentes com estímulos dos conjuntos A e B, separadamente. Três estudantes também realizaram a substituição mútua entre estímulos dos conjuntos A e B na Etapa 3. Esses resultados sugerem a formação de cinco classes de estímulos (A1B1, A2B2, etc.), cada uma consistindo de estímulos que ocuparam a mesma função ordinal em diferentes seqüências. Os resultados têm implicações para a análise de comportamento simbólico complexo. Merecem consideração, também, aspectos metodológicos que favoreceram a aprendizagem relacional e a emergência de comportamento novo.

Crystal structure, DNA binding studies, nucleolytic property and topoisomerase I inhibition of zinc complex with 1,10-phenanthroline and 3-methyl-picolinic acid

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

PRP8 intein in Ajellomycetaceae family pathogens: Sequence analysis, splicing evaluation and homing endonuclease activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complex mating behavior in Adelosgryllus rubricephalus (Orthoptera, Phalangopsidae, Grylloidea)

Descrevemos o comportamento reprodutivo de Adelosgryllus rubricephalus Mesa & Zefa, 2004. em observações realizadas em laboratório verificamos a seguinte seqüência no comportamento de acasalamento: (1) reconhecimento sexual por antenação; (2) corte, em que o macho volta seu abdômen em direção à fêmea, vibra as antenas médio-lateralmente, treme o corpo ântero-posteriormente e estridula intermitentemente, enquanto a fêmea receptiva toca a ponta do abdômen, os cercos e os fêmures posteriores do macho, com seus palpos ou tarsos anteriores; o macho então fica imóvel por alguns segundos, expõe o espermatóforo e ambos retomam a seqüência comportamental descrita acima; (3) cópula: o macho coloca-se sob a fêmea, com suas tégminas inclinadas para frente, anexa sua genitália à dela e promove a transferência do esperma; a fêmea desce de cima do macho e ocorre brevemente a posição end-to-end durante a separação do casal; (4) pós-cópula: não há comportamento de guarda; o macho retém o espermatóforo e o ingere. Quantificamos o intervalo de tempo das principais etapas do acasalamento e discutimos suas possíveis implicações no comportamento observado.

Relation of pretreatment sequence diversity in NS5A region of HCV genotype 1 with immune response between pegylated-INF/ribavirin therapy outcomes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hydroxymethylnitrofurazone:Dimethyl-beta-cyclodextrin Inclusion Complex: A Physical-Chemistry Characterization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metamorphism and PGE-Au content of chromitite from the Ipanema mafic/ultramafic Complex, Minas Gerais, Brazil

The Santa Cruz massif, which forms part of the Ipanema mafic/ultramafic Complex, Minas Gerais, Brazil, has an exposed upward sequence of metadunite, metaharzburgite (including three separate chromitite layers), metapyroxenite, metagabbro, and metaanorthosite. Primary igneous chromite grains in the main chromitite layer are poikiloblastic and tectonically fragmented, and have a narrow (10-20 mum) margin of chromian spinel. Cataclased chromite fragments are extensively replaced and mantled by chromian spinel; they have a composite margin comprised of an inner zone of more aluminous spinel and an euhedral outer zone of more Cr-rich spinel, representing granulite and amphibolite facies metamorphic events, respectively. The contents of platinum-group elements (PGE) and Au in chromite separates are relatively high (Os 45, Ir 23, Ru 136, Rh 19, Pt 98, Pd 63, and Au 83 ppb), and significantly enriched (similar to 4x) over whole rock values. Platinum-group minerals are not observed and micrometre-sized inclusions of sulfide minerals (chalcopyrite and pentlandite) in relict chromite are rare. However, comparison of mineral proportions in the separated chromite and whole rock shows that the precious metals are hosted predominantly in the relict igneous chromite grains, rather than the secondary chromian spinel and primary and secondary Mg-rich silicates. The major element composition and average chondrite-normalized PGE pattern of the separated chromite correspond to S-poor stratiform chromitite. We suggest that the precious metals accumulated with chromite during crystallization of a S-poor magma, and were not remobilized in the relict chromite during the subsequent high grade metamorphism.

Genetic variability of Brazilian strains of the Microcystis aeruginosa complex (Cyanobacteria/Cyanophyceae) using the phycocyanin intergenic spacer and flanking regions (cpcBA)

The genetic and morphological variability among 15 Brazilian strains of Microcystis aeruginosa (Kütz.) Kütz. collected from four locations was examined and compared with several reference strains of M. aeruginosa, M. viridis (A. Br.) Lemm. and M. wesenbergii (Kom.) Kom. in Kondr. Brazilian strains were classified by morphological features and by comparison of the nucleotide sequences of the cpcBA intergenic spacer and flanking regions. Our results indicate that Brazilian strains classified as M. aeruginosa are phylogenetically diverse compared with reference strains of M. aeruginosa and that the current taxonomy underestimates genetic diversity within M. aeruginosa. The data also demonstrate that morphological criteria alone are inadequate to characterize Microcystis species. Although colonial characters were shown to vary considerably in culture, some genetic lineages demonstrated consistent cellular diameter ranges, indicating that cell size has value as a taxonomic character. The detection of six M. aeruginosa genotypes in a single water body indicates that morphological approaches can also seriously underestimate the diversity of Microcystis bloom populations.

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.

Taenia solium and Taenia saginata: Identification of sequence characterized amplified region (SCAR) markers

Cysticercosis is one of the most important zoonosis, not only because of the effects on animal health and its economic consequences, but also due to the serious danger it poses to humans. The two main parasites involved in the taeniasis-cysticercosis complex in Brazil are Taenia saginata and Taenia solium. Differentiating between these two parasites is important both for disease control and for epidemiological studies. The purpose of this work was to identify genetic markers that could be used to differentiate these parasites. Out of 120 oligonucleotide decamers tested in random amplified polymorphic DNA (RAPD) assays, 107 were shown to discriminate between the two species of Taenia. Twenty-one DNA fragments that were specific for each species of Taenia were chosen for DNA cloning and sequencing. Seven RAPD markers were converted into sequence characterized amplified region (SCAR) markers with two specific for T. saginata and five specific for T. solium as shown by agarose gel electrophoresis. These markers were developed as potential tools to differentiate T. solium from T. saginata in epidemiological studies. © 2007 Elsevier Inc. All rights reserved.

The Mycobacterium tuberculosis Rv2540c DNA sequence encodes a bifunctional chorismate synthase

Background. The emergence of multi- and extensively-drug resistant Mycobacterium tuberculosis strains has created an urgent need for new agents to treat tuberculosis (TB). The enzymes of shikimate pathway are attractive targets to the development of antitubercular agents because it is essential for M. tuberculosis and is absent from humans. Chorismate synthase (CS) is the seventh enzyme of this route and catalyzes the NADH- and FMN-dependent synthesis of chorismate, a precursor of aromatic amino acids, naphthoquinones, menaquinones, and mycobactins. Although the M. tuberculosis Rv2540c (aroF) sequence has been annotated to encode a chorismate synthase, there has been no report on its correct assignment and functional characterization of its protein product. Results. In the present work, we describe DNA amplification of aroF-encoded CS from M. tuberculosis (MtCS), molecular cloning, protein expression, and purification to homogeneity. N-terminal amino acid sequencing, mass spectrometry and gel filtration chromatography were employed to determine identity, subunit molecular weight and oligomeric state in solution of homogeneous recombinant MtCS. The bifunctionality of MtCS was determined by measurements of both chorismate synthase and NADH:FMN oxidoreductase activities. The flavin reductase activity was characterized, showing the existence of a complex between FMN ox and MtCS. FMNox and NADH equilibrium binding was measured. Primary deuterium, solvent and multiple kinetic isotope effects are described and suggest distinct steps for hydride and proton transfers, with the former being more rate-limiting. Conclusion. This is the first report showing that a bacterial CS is bifunctional. Primary deuterium kinetic isotope effects show that C4-proS hydrogen is being transferred during the reduction of FMNox by NADH and that hydride transfer contributes significantly to the rate-limiting step of FMN reduction reaction. Solvent kinetic isotope effects and proton inventory results indicate that proton transfer from solvent partially limits the rate of FMN reduction and that a single proton transfer gives rise to the observed solvent isotope effect. Multiple isotope effects suggest a stepwise mechanism for the reduction of FMNox. The results on enzyme kinetics described here provide evidence for the mode of action of MtCS and should thus pave the way for the rational design of antitubercular agents. © 2008 Ely et al; licensee BioMed Central Ltd.

At least two indigenous species of the Bemisia tabaci complex are present in Brazil

Bemisia tabaci is one of the most important global agricultural insect pests, being a vector of emerging plant viruses such as begomoviruses and criniviruses that cause serious problems in many countries. Although knowledge of the genetic diversity of B. tabaci populations is important for controlling this pest and understanding viral epidemics, limited information is available on this pest in Brazil. A survey was conducted in different locations of São Paulo and Mato Grosso states, and the phylogenetic relationships of B. tabaci individuals from 43 populations sampled from different hosts were analysed based on partial mitochondrial cytochrome oxidase 1 gene (mtCOI) sequences. According to the recently proposed classification of the B. tabaci complex, which employs the 3.5% mtCOI sequence divergence threshold for species demarcation, most of the specimens collected were found to belong to the Middle East-Asia Minor 1 species, which includes the invasive populations of the commonly known B biotype, within the Africa/Middle East/Asia Minor high-level group. Three specimens collected from Solanun gilo and Ipomoea sp. were grouped together and could be classified in the New World species that includes the commonly known A biotype. However, six specimens collected from Euphorbia heterophylla, Xanthium cavanillesii and Glycine maxima could not be classified into any of the 28 previously proposed species, although according to the 11% mtCOI sequence divergence threshold, they belong to the New World high-level group. These specimens were classified into a new recently proposed species named New World 2 that includes populations from Argentina. Middle East-Asia Minor 1, New World and New World 2 were differentiated by RFLP analysis of the mtCOI gene using TaqI enzyme. Taq I analysis in silico also differentiates these from Mediterranean species, thus making this method a convenient tool to determine population dynamics, especially critical for monitoring the presence of this exotic pest in Brazil. © 2012 Blackwell Verlag, GmbH.

Cooperative RNA Polymerase Molecules Behavior on a Stochastic Sequence-Dependent Model for Transcription Elongation

The transcription process is crucial to life and the enzyme RNA polymerase (RNAP) is the major component of the transcription machinery. The development of single-molecule techniques, such as magnetic and optical tweezers, atomic-force microscopy and single-molecule fluorescence, increased our understanding of the transcription process and complements traditional biochemical studies. Based on these studies, theoretical models have been proposed to explain and predict the kinetics of the RNAP during the polymerization, highlighting the results achieved by models based on the thermodynamic stability of the transcription elongation complex. However, experiments showed that if more than one RNAP initiates from the same promoter, the transcription behavior slightly changes and new phenomenona are observed. We proposed and implemented a theoretical model that considers collisions between RNAPs and predicts their cooperative behavior during multi-round transcription generalizing the Bai et al. stochastic sequence-dependent model. In our approach, collisions between elongating enzymes modify their transcription rate values. We performed the simulations in Mathematica® and compared the results of the single and the multiple-molecule transcription with experimental results and other theoretical models. Our multi-round approach can recover several expected behaviors, showing that the transcription process for the studied sequences can be accelerated up to 48% when collisions are allowed: the dwell times on pause sites are reduced as well as the distance that the RNAPs backtracked from backtracking sites. © 2013 Costa et al.

Using the bottom-up and outside-in sequence for panfacial fracture management: Does it provide a clinical significance?

Panfacial fractures usually refer to simultaneous facial fractures, which affect the upper, middle, and lower thirds of the face. The management of panfacial fracture is complex because of the lack of reliable landmarks. Literature has shown many approaches for management of panfacial fractures. Every segment of bone has a precise function in the repair. Therefore, the bottom-up and outside-in sequence is the most widely used approach in the management of panfacial fractures. These facial fractures present remarkable challenges for both experienced and inexperienced surgeons. This article aimed to report a case of a panfacial fracture (mandibular condylar and symphysis fractures associated with an atypical Le Fort III fracture) in a 48-year-old man. The patient was successfully treated using bottom-up and outside-in sequence by accessing all facial injuries. Postoperatively, radiograph examination revealed good reduction and fixation of titanium plates, and physical examination revealed good functional and esthetic outcomes. Copyright © 2013 by Mutaz B. Habal, MD.

Analysis of inteins in the Candida parapsilosis complex for simple and accurate species identification

Inteins are coding sequences that are transcribed and translated with flanking sequences and then are excised by an autocatalytic process. There are two types of inteins in fungi, mini-inteins and full-length inteins, both of which present a splicing domain containing well-conserved amino acid sequences. Full-length inteins also present a homing endonuclease domain that makes the intein a mobile genetic element. These parasitic genetic elements are located in highly conserved genes and may allow for the differentiation of closely related species of the Candida parapsilosis (psilosis) complex. The correct identification of the three psilosis complex species C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis is very important in the clinical setting for improving antifungal therapy and patient care. In this work, we analyzed inteins that are present in the vacuolar ATPase gene VMA and in the threonyl-tRNA synthetase gene ThrRS in 85 strains of the Candida psilosis complex (46 C. parapsilosis, 17 C. metapsilosis, and 22 C. orthopsilosis). Here, we describe an accessible and accurate technique based on a single PCR that is able to differentiate the psilosis complex based on the VMA intein. Although the ThrRS intein does not distinguish the three species of the psilosis complex by PCR product size, it can differentiate them by sequencing and phylogenetic analysis. Furthermore, this intein is unusually present as both mini- and full-length forms in C. orthopsilosis. Additional population studies should be performed to address whether this represents a common intraspecific variability or the presence of subspecies within C. orthopsilosis. Copyright © 2013, American Society for Microbiology. All Rights Reserved.