Showing papers by "Universidade Federal de Santa Catarina published in 2007"

Atlantic reef fish biogeography and evolution

Abstract: Aim To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment. Location Atlantic Ocean. Methods The distributions of 2605 species of reef fishes were compiled for 25 areas of the Atlantic and southern Africa. Maximum-parsimony and distance analyses were employed to investigate biogeographical relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e. speciation processes), and evaluate the operation of the main biogeographical barriers and/or filters. Results Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical provinces in the Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2) isolation as a result of biogeographical barriers, and (3) stochastic accretion by means of dispersal between provinces. The timing of divergence events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and Benguela) clearly act as ‘filters’ by restricting dispersal but at the same time allowing occasional crossings that apparently lead to the establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences among provinces, apparently provide a mechanism for much of the recent diversification of reef fishes in the Atlantic. Main conclusions Our data set indicates that both historical events (e.g. Tethys closure) and relatively recent dispersal (with or without further speciation) have had a strong influence on Atlantic tropical marine biodiversity and have contributed to the biogeographical patterns we observe today; however, examples of the latter process outnumber those of the former.

Procedimentos metodológicos na construção do conhecimento científico: a pesquisa bibliográfica

Abstract: This article concerns bibliographic research in the context of production of knowledge, as a methodological procedure that offers the researcher the possibility of seeking solutions to a research problem. It recognizes the need to present the scientific method chosen by the researcher; to present the forms of construction of the methodological design and the choice of procedures; and demonstrates how the presentation and analysis of the data obtained is configured. It also presents a methodological design of successive approximations, considering that the flexibility in the apprehension of data guarantees the dialectical movement in which the object of study can be constantly revised. That is, it postulates that bibliographic research involves conducting a tireless movement of apprehension of objectives, observance of steps, reading, questioning and critical interlocution with the bibliographic material and this demands epistemological vigilance.

The history of star-forming galaxies in the Sloan Digital Sky Survey

Abstract: This paper, the sixth in the Semi-Empirical Analysis of Galaxies series, studies the evolution of 82 302 star-forming (SF) galaxies from the Sloan Digital Sky Survey. Star formation histories (SFHs) are derived from detailed spectral fits obtained with our publicly available spectral synthesis code STARLIGHT. Our main goals are to explore new ways to derive SFHs from the synthesis results and apply them to investigate how SFHs vary as a function of nebular metallicity (Zneb). A number of refinements over our previous work are introduced, including (1) an improved selection criterion; (2) a careful examination of systematic residuals around Hβ; (3) self-consistent determination of nebular extinctions and metallicities; (4) tests with several Zneb estimators; (5) a study of the effects of the reddening law adopted and of the relation between nebular and stellar extinctions and the interstellar component of the Na I D doublet.

Seasonality of influenza in Brazil: a traveling wave from the Amazon to the subtropics

Abstract: Influenza circulation and mortality impact in tropical areas have not been well characterized. The authors studied the seasonality of influenza throughout Brazil, a geographically diverse country, by modeling influenza-related mortality and laboratory surveillance data. Monthly time series of pneumonia and influenza mortality were obtained from 1979 to 2001 for each of the 27 Brazilian states. Detrended time series were analyzed by Fourier decomposition to describe the amplitude and timing of annual and semiannual epidemic cycles, and the resulting seasonal parameters were compared across latitudes, ranging from the equator (+5 degrees N) to the subtropics (-35 degrees S). Seasonality in mortality was most pronounced in southern states (winter epidemics, June-July), gradually attenuated toward central states (15 degrees S) (p < 0.001), and remained low near the equator. A seasonal southward traveling wave of influenza was identified across Brazil, originating from equatorial and low-population regions in March-April and moving toward temperate and highly populous regions over a 3-month period. Laboratory surveillance data from recent years provided independent confirmation that mortality peaks coincided with influenza virus activity. The direction of the traveling wave suggests that environmental forces (temperature, humidity) play a more important role than population factors (density, travel) in driving the timing of influenza epidemics across Brazil.

Connecting TNF-alpha signaling pathways to iNOS expression in a mouse model of Alzheimer's disease: relevance for the behavioral and synaptic deficits induced by amyloid beta protein.

Abstract: Increased brain deposition of amyloid beta protein (Abeta) and cognitive deficits are classical signals of Alzheimer's disease (AD) that have been highly associated with inflammatory alterations. The present work was designed to determine the correlation between tumor necrosis factor-alpha (TNF-alpha)-related signaling pathways and inducible nitric oxide synthase (iNOS) expression in a mouse model of AD, by means of both in vivo and in vitro approaches. The intracerebroventricular injection of Abeta(1-40) in mice resulted in marked deficits of learning and memory, according to assessment in the water maze paradigm. This cognition impairment seems to be related to synapse dysfunction and glial cell activation. The pharmacological blockage of either TNF-alpha or iNOS reduced the cognitive deficit evoked by Abeta(1-40) in mice. Similar results were obtained in TNF-alpha receptor 1 and iNOS knock-out mice. Abeta(1-40) administration induced an increase in TNF-alpha expression and oxidative alterations in prefrontal cortex and hippocampus. Likewise, Abeta(1-40) led to activation of both JNK (c-Jun-NH2-terminal kinase)/c-Jun and nuclear factor-kappaB, resulting in iNOS upregulation in both brain structures. The anti-TNF-alpha antibody reduced all of the molecular and biochemical alterations promoted by Abeta(1-40). These results provide new insights in mouse models of AD, revealing TNF-alpha and iNOS as central mediators of Abeta action. These pathways might be targeted for AD drug development.

Involvement of glutamate and reactive oxygen species in methylmercury neurotoxicity

Abstract: This review addresses the mechanisms of methylmercury (MeHg)-induced neurotoxicity, specifically examining the role of oxidative stress in mediating neuronal damage. A number of critical findings point to a central role for astrocytes in mediating MeHg-induced neurotoxicity as evidenced by the following observations: a) MeHg preferentially accumulates in astrocytes; b) MeHg specifically inhibits glutamate uptake in astrocytes; c) neuronal dysfunction is secondary to disturbances in astrocytes. The generation of reactive oxygen species (ROS) by MeHg has been observed in various experimental paradigms. For example, MeHg enhances ROS formation both in vivo (rodent cerebellum) and in vitro (isolated rat brain synaptosomes), as well as in neuronal and mixed reaggregating cell cultures. Antioxidants, including selenocompounds, can rescue astrocytes from MeHg-induced cytotoxicity by reducing ROS formation. We emphasize that oxidative stress plays a significant role in mediating MeHg-induced neurotoxic damage with active involvement of the mitochondria in this process. Furthermore, we provide a mechanistic overview on oxidative stress induced by MeHg that is triggered by a series of molecular events such as activation of various kinases, stress proteins and other immediate early genes culminating in cell damage.

Antioxidant Activity and Total Phenolic Content of Some Brazilian Species

Abstract: The antioxidant activity of extracts and fractions of six vegetal species from the Brazilian Atlantic Forest were determined. The total antioxidant activity was assessed based on the scavenging activity of the stable DPPH free radical. Eight extracts or fractions of plants showed significant DPPH scavenging activity (IC50 � 10.0mg=mL) compared with the values obtained for ascorbic acid (IC50 ¼ 8.4mg=mL) and gallic acid (IC50 ¼ 2.6mg=mL). The extracts or fractions were as follows: ethanol extracts of leaves, flowers, and stems of Baccharis illinita DC., ethanol extracts of leaves and stems of B. platypoda DC., hydroalcoholic extract and ethyl acetate fraction of leaves of Cyathea phalerata Mart. and hydroalcoholic extract of bark of Trichilia catigua A. Juss. Seven flavonoids present in the plant extracts were also investigated. The most active compounds were taxifolin, quercetin, and luteolin, which possess the catechol group 3 0 ,4 0 diOH. In addition, the total phenolic or flavonoid contents of these extracts and fractions were evaluated. The phenolic content of the sample was determined using Folin-Ciocalteu reagent and varied from 489.07 to 11.29 mg=g dry weight expressed as gallic acid equivalents (GAE). The total flavonoid concentrations, detected using 2% aluminum chloride, varied from 61.82 to 5.6 mg quercetin equivalents (QE)=g dry weight. These results suggest that the level of antioxidant activity in these plants varies by a great extent. They also suggest that the phenolic content in these plants provides substantial antioxidant activity. The flora of Brazil appears to be a rich and interesting source for supplementary ethnomedical and phytochemical studies.

Oxidative stress in Perna perna and other bivalves as indicators of environmental stress in the Brazilian marine environment: antioxidants, lipid peroxidation and DNA damage.

Abstract: Oxidative stress can take place in marine bivalves under a series of environmental adverse conditions. The study of different systems related to oxidative stress in these organisms can give important information about their physiological status and also about environmental health. Bivalves have been proposed as good sentinel organisms in pollution monitoring studies through the analysis of biochemical biomarkers, and most of the biomarkers analyzed are those related to oxidative stress. However, it is very important to know how other environmental factors not associated to the presence of pollutants might affect these parameters. We have studied a series of mechanisms related to oxidative stress in mussels which inhabit the Brazilian coast, especially in Perna perna species, subjected to different stress conditions, such as the exposure to different contaminants in the laboratory and in the field, the exposure of mussels to air and re-submersion, simulating the tidal oscillations, and in mussels collected at different seasons. Both oxidative damage levels and antioxidant defense systems were strongly affected by the different environmental stress. This review summarizes the data obtained in some studies carried out in bivalves from the Brazilian coast.

A proposal of generic and subgeneric abbreviations for phlebotomine sandflies (diptera: psychodidae: phlebotominae) of the world

Abstract: The systematics of Phlebotomine sandflies has been studied and discussed since the beginning of the 20th century, and many systems have been proposed. Complex and well-based systems, dividing Phlebotominae in many genera and subgenera, proposed for Old and New World species, have been progressively understood and accepted by the workers in the subfamily. Due to its complex nature, a system of abbreviations, similar to that utilized for Culicidae, is proposed here for these groups of Phlebotominae. It uses two letters for genera and three for subgenera.

Dectin-1 Interaction with Mycobacterium tuberculosis Leads to Enhanced IL-12p40 Production by Splenic Dendritic Cells

Abstract: Dectin-1 is a fungal pattern recognition receptor that binds to beta-glucans and triggers cytokine production by facilitating interaction with TLR2 or by directly activating spleen tyrosine kinase (Syk). To assess the possible role of Dectin-1 in the innate response to mycobacteria, we used an in vitro system in which IL-12p40 production is measured in splenic dendritic cells (SpDC) following exposure to live Mycobacterium tuberculosis bacilli. Treatment of SpDC with laminarin or glucan phosphate, two molecules known to block Dectin-1-dependent activity, led to a reduction in M. tuberculosis-induced IL-12p40 as well as IL-12p70 production. Moreover, SpDC from Dectin-1-/- chimeric mice displayed reduced IL-12p40 production in response to mycobacteria when compared with Dectin-sufficient DC. Laminarin treatment also inhibited mycobacterial-induced IL-12p40 production in DC from TLR2-/- mice, arguing that Dectin-1 functions independently of TLR2 signaling in this system. Importantly, a Dectin-1 fusion protein was found to directly bind to live mycobacteria in a laminarin-inhibitable manner indicating the presence of ligands for the receptor in the bacterium and laminarin pretreatment resulted in reduced association of mycobacteria to SpDC. In additional experiments, mycobacterial stimulation was shown to be associated with increased phosphorylation of Syk and this response was inhibited by laminarin. Furthermore, pharmacologic inhibition of Syk reduced the M. tuberculosis-induced IL-12p40 response. Together, these findings support a role for Dectin-1 in promoting M. tuberculosis-induced IL-12p40 production by DC in which the receptor augments bacterial-host cell interaction and enhances the subsequent cytokine response through an unknown mechanism involving Syk signaling.

Reprodutibilidade e validade do Questionário Internacional de Atividade Física (IPAQ) em homens idosos

Abstract: It is necessary to efficiently and economically find means to quantify the level of physical activity of the population. Questionnaires are viable and economical; however, their trustworthiness is questionable. This study aimed to determine the reproducibility and validity of the International Physical Activity Questionnaire (IPAQ) in elderly men. The sampling was composed of 29 elderly men over the age of 60, average age of 66.6 years (SD = 4.3), who were members of the extension program at the Federal University of Santa Catarina. The instruments used were: a) IPAQ extended version; b) pedometer and c) Bouchard's Physical Activity Diary (PAD). For reproducibility, the IPAQ was applied twice with a 21 day interval (rs = 0.95). The statistical analysis used was Spearman Correlation (rs); Concordance Percentile (%C); Kappa Index (k); and Bland and Altman plot. The sample was divided using the median as criterion. The reproducibility showed a correlation of rs 0.95. The combination between IPAQ and PAD was: rs = 0.38; %C = 69 and k = 0.04. The combination between IPAQ and the Pedometer was: rs = 0.24; %C = 62 and k = 0.19. It was concluded that the validity varied from moderate to low while the reproducibility was adequate.

Reef fish community structure on coastal islands of the southeastern Brazil: the influence of exposure and benthic cover

Abstract: Patterns of community structure in the marine environment are strongly influenced by population relationships to biotic and physical gradients. The aim of this work is to explore the relationships of tropical rocky reef fish assemblages to wave exposure and benthic coverage in a gradient of distance from the coast. The study was conducted on the Guarapari Islands, southeastern Brazilian coast. Fish were sampled by underwater visual census (166 transects) and benthic cover was estimated with quadrats (223 replicates). Two main kinds of habitats were found to be derived from the close interrelation between exposure and benthic coverage: (1) exposed areas subjected to major hydrodynamic forcing, and (2) sheltered or moderately exposed areas. The first group is associated with mid-water schooling species like planktivorous labrids and Chromis, piscivorous Caranx, as well as gregarious omnivores like Abudefduf and Diplodus. In terms of benthic composition, macroalgae and encrusting calcareous algae prevail in this high-energy habitat. The second group is characterized by site-attached and reef associated species like territorial pomacentrids, invertebrate feeders such as Halichoeres poeyi and Chaetodon striatus, and small cryptobenthic fishes (e.g. blenniids and labrisomids). Turf algae, zoanthids and massive corals dominate this environment. Environmental plasticity is also common with some genera showing high abundances in all habitats (e.g. Holocentrus, Haemulon, Acanthurus). Examples of the coupling of food availability and fish abundance were found. Planktivores, territorial herbivores, macroalgae browsers and spongivores were positively related with the abundance of their preferred food items along the exposure gradient. Within-family analyses of Pomacentridae and Labridae showed that niche partitioning is likely occurring and seems to be mediated by swimming ‘ability’ and associated feeding performance.

Inverse Semigroups and Combinatorial C*-Algebras

Abstract: We describe a special class of representations of an inverse semigroup S on Hilbert's space which we term "tight". These representations are supported on a subset of the spectrum of the idempotent semilattice of S, called the "tight spectrum", which is in turn shown to be precisely the closure of the space of ultra-filters, once filters are identified with semicharacters in a natural way. These representations are moreover shown to correspond to representations of the C*-algebra of the groupoid of germs for the action of S on its tight spectrum. We then treat the case of certain inverse semigroups constructed from a semigroupoid, generalizing and inspired by inverse semigroups constructed from ordinary and higher rank graphs. The tight representations of this inverse semigroup are in one-to-one correspondence with representations of the semigroupoid, and the semigroupoid algebra is given a groupoid model. The groupoid which arises from this construction is shown to be the same as the boundary path groupoid of Farthing, Muhly and Yeend, at least in the singly aligned, sourceless case.

Catalytic Promiscuity in Biomimetic Systems: Catecholase-like Activity, Phosphatase-like Activity, and Hydrolytic DNA Cleavage Promoted by a New Dicopper(II) Hydroxo-Bridged Complex

Abstract: Presented in this Communication are the structure, physicochemical properties, and catalytic promiscuity of a new dinuclear CuII(mu-OH)CuII complex containing a novel N,O-donor symmetric dinucleating ligand.

Effect of two active compounds obtained from the essential oil of Cordia verbenacea on the acute inflammatory responses elicited by LPS in the rat paw

Abstract: Background and purpose: α-Humulene and trans-caryophyllene are sesquiterpene compounds identified in the essential oil of Cordia verbenacea which display topical and systemic anti-inflammatory effects in different experimental models. However, the molecular mechanisms through which they exert their anti-inflammatory activity still remain unclear. Here, we evaluate the effects of α-humulene and trans-caryophyllene on the acute inflammatory responses elicited by LPS.

The relation between family socioeconomic trajectories from childhood to adolescence and dental caries and associated oral behaviours

Abstract: Objectives: To investigate the influence of family socioeconomic trajectories from childhood to adolescence on dental caries and associated behaviours. Design: Population-based birth cohort. Setting: Representative sample of the population of subjects born in 1982 in Pelotas, Brazil. Participants: Adolescents (n = 888) aged 15 years old were dentally examined and interviewed. Main outcome measures: Dental caries index (DMFT), care index (F/DMFT), tooth brushing, flossing and pattern of dental services use. Main results: Adolescents who were always poor showed, in general, a worse pattern of dental caries, whereas adolescents who never were poor had a better pattern of dental caries. Adolescents who had moved from poverty in childhood to non-poverty in adolescence and those who had moved from non-poverty in childhood to poverty in adolescence had similar dental pattern to those who were always poor except for the pattern of dental services use, which was higher in the first group. In all groups girls had fewer carious teeth, better oral hygiene habits and higher dental services use than boys. Conclusion: Poverty in at least one stage of the lifespan has a harmful effect on dental caries, oral behaviours and dental services use. Belonging to upwardly mobile families between childhood and adolescence only contributed to improved dental care.

Sentidos e significados do trabalho: explorando conceitos, variáveis e estudos empíricos brasileiros

Abstract: O artigo apresenta uma breve revisao da literatura sobre sentidos e significados que trabalhadores atribuem aos seus trabalhos e identifica perspectivas teoricas que diferenciam sentidos e significados, em contrapartida a outras que os tratam como um unico fenomeno. Foi possivel demonstrar que trata-se de tematica ainda pouco explorada e cuja maioria dos estudos esta baseada nas investigacoes desenvolvidas pelo Meaning of Work International Research Team ([MOW], 1987) e, mais recentemente, por Morin (2001). As variaveis adotadas nas pesquisas do fenomeno no Brasil advem, predominantemente, dos trabalhos do MOW e sao a centralidade do trabalho, as normas sociais do trabalho e os resultados valorizados do trabalho. Verifica-se a importância da multidisciplinaridade para a compreensao da atribuicao de sentidos e significados do trabalho pelos sujeitos dado que se trata de um construto psicologico multidimensional e dinâmico, e que resulta da interacao entre variaveis pessoais e ambientais relacionadas ao trabalho.

Tooth loss and associated socioeconomic, demographic, and dental-care factors in Brazilian adults: an analysis of the Brazilian Oral Health Survey, 2002-2003

Abstract: O objetivo deste estudo foi estimar a prevalencia de perdas dentarias em adultos de 35 a 44 anos de idade. Alem disso, foram testadas associacoes entre as perdas dentarias e condicoes demograficas, socio-economicas e com utilizacao de servicos odontologicos. Foram analisados os dados de 13.431 participantes do estudo epidemiologico nacional de saude bucal realizado em 2002-2003. O numero de perdas dentarias (£ 12 e > 12) foi o desfecho investigado. As variaveis independentes incluiram localizacao geografica, genero, cor da pele, idade, renda per capita, escolaridade, tempo decorrido desde a ultima consulta odontologica e tipo de servico utilizado. Foram estimadas as razoes de prevalencia bruta e ajustada atraves de regressao de Poisson. Edentulismo atingiu 9% da amostra; a mediana de dentes perdidos foi igual a 11. Perdas dentarias foram fortemente associadas com individuos residentes em zona rural, com as mulheres, com os mais pobres, com os de menor escolaridade e com aqueles de idade mais avancada. Usuarios do servico publico e aqueles que consultaram dentista ha mais tempo tambem apresentaram maior prevalencia do agravo mesmo apos o ajuste por variaveis socio-economicas e demograficas.

Effects of breastfeeding and sucking habits on malocclusion in a birth cohort study

Abstract: OBJECTIVE: To estimate the prevalence of malocclusion and to examine the effects of breastfeeding and non-nutritive sucking habits on dentition in six-year-old children. METHODS: A cross-sectional study was carried out nested into a birth cohort conducted in Pelotas, Southern Brazil, in 1999. A sample of 359 children was dentally examined and their mothers interviewed. Anterior open bite and posterior cross bite were recorded using the Foster & Hamilton criteria. Information regarding breastfeeding and non-nutritive sucking habits was collected at birth, in the first, third, sixth and 12th months of life, and at six years of age. Control variables included maternal schooling and child's birthweight, cephalic perimeter, and sex. Data were analyzed by Poisson regression. RESULTS: Prevalence of anterior open bite was 46.2%, and that of posterior cross bite was 18.2%. Non-nutritive sucking habits between 12 months and four years of age and digital sucking at age six years were the main risk factors for anterior open bite. Breastfeeding for less than nine months and regular use of pacifier between age 12 months and four years were risk factors for posterior cross bite. Interaction between duration of breastfeeding and the use of pacifier was identified for posterior cross bite. CONCLUSIONS: Given that breastfeeding is a protective factor for other diseases of infancy, our findings indicate that the common risks approach is the most appropriate for the prevention of posterior cross bite in primary or initial mixed dentition.

Proinflammatory and oxidative stress markers in patients with periodontal disease.

Abstract: Objective. To evaluate the involvement of proinflammatory and oxidative stress markers in gingival tissue in individuals with chronic periodontitis. Subject and methods. Eighteen subjects were divided in two groups: experimental (age 52.9±5.0) and control (age 51.1±9.6). The activities of enzymatic antioxidants such as catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase, nonenzymatic antioxidants: total glutathione and reduced glutathione, oxidized glutathione (GSSG), thiobarbituric acid reactive substances (TBARS), and myeloperoxidase activity (MPO) were evaluated in gingival tissues from interproximal sites. Statistical differences between groups were determined by independent Student t test and P<.05. Results. Individuals with periodontal disease exhibited a significant increase in the activities of MPO, GPx, GST, and also in TBARS and GSSG levels in gingival tissue compared to the control group (P<.05). Conclusion. The results of the present work showed an important correlation between oxidative stress biomarkers and periodontal disease.