27 resultados para Classificació AMS::92 Biology and other natural sciences

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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The reproductive biology and pollination mechanisms of Govenia utriculata (Sw.) Lindl. were studied in a mesophytic semideciduous forest at Serra do Japi, south-eastern Brazil. The floral visitors and pollination mechanisms were recorded, and experimental pollinations were carried out to determine the breeding system of this species. Populations of G. utriculata growing at Serra do Japi are exclusively visited and pollinated by two species of hoverflies in the genus Salpingogaster (Diptera: Syrphidae) that are attracted by deceit to the flowers of this orchid species. The lip apex and the column base present small brownish and yellow to orange spots that mimic pollen clusters. Govenia utriculata is self-compatible, but pollinator dependent. Natural fruit set was low (10%), but similar to that of other non-obligatorily autogamous sympatric orchid species that occur at Serra do Japi and of other fly-pollinated orchid species pollinated through deceptive mechanisms.

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Context. Compact groups of galaxies are entities that have high densities of galaxies and serve as laboratories to study galaxy interactions, intergalactic star formation and galaxy evolution. Aims. The main goal of this study is to search for young objects in the intragroup medium of seven compact groups of galaxies: HCG 2, 7, 22, 23, 92, 100 and NGC 92 as well as to evaluate the stage of interaction of each group. Methods. We used Fabry-Perot velocity fields and rotation curves together with GALEX NUV and FUV images and optical R-band and HI maps. Results. (i) HCG 7 and HCG 23 are in early stages of interaction; (ii) HCG 2 and HCG 22 are mildly interacting; and (iii) HCG 92, HCG 100 and NGC 92 are in late stages of evolution. We find that all three evolved groups contain populations of young blue objects in the intragroup medium, consistent with ages < 100 Myr, of which several are younger than < 10 Myr. We also report the discovery of a tidal dwarf galaxy candidate in the tail of NGC 92. These three groups, besides containing galaxies that have peculiar velocity fields, also show extended HI tails. Conclusions. Our results indicate that the advanced stage of evolution of a group, together with the presence of intragroup HI clouds, may lead to star formation in the intragroup medium. A table containing all intergalactic HII regions and tidal dwarf galaxies confirmed to date is appended.

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Mycoplasma suis, the causative agent of porcine infectious anemia, has never been cultured in vitro and mechanisms by which it causes disease are poorly understood. Thus, the objective herein was to use whole genome sequencing and analysis of M. suis to define pathogenicity mechanisms and biochemical pathways. M. suis was harvested from the blood of an experimentally infected pig. Following DNA extraction and construction of a paired end library, whole-genome sequencing was performed using GS-FLX (454) and Titanium chemistry. Reads on paired-end constructs were assembled using GS De Novo Assembler and gaps closed by primer walking; assembly was validated by PFGE. Glimmer and Manatee Annotation Engine were used to predict and annotate protein-coding sequences (CDS). The M. suis genome consists of a single, 742,431 bp chromosome with low G+C content of 31.1%. A total of 844 CDS, 3 single copies, unlinked rRNA genes and 32 tRNAs were identified. Gene homologies and GC skew graph show that M. suis has a typical Mollicutes oriC. The predicted metabolic pathway is concise, showing evidence of adaptation to blood environment. M. suis is a glycolytic species, obtaining energy through sugars fermentation and ATP-synthase. The pentose-phosphate pathway, metabolism of cofactors and vitamins, pyruvate dehydrogenase and NAD(+) kinase are missing. Thus, ribose, NADH, NADPH and coenzyme A are possibly essential for its growth. M. suis can generate purines from hypoxanthine, which is secreted by RBCs, and cytidine nucleotides from uracil. Toxins orthologs were not identified. We suggest that M. suis may cause disease by scavenging and competing for host nutrients, leading to decreased life-span of RBCs. In summary, genome analysis shows that M. suis is dependent on host cell metabolism and this characteristic is likely to be linked to its pathogenicity. The prediction of essential nutrients will aid the development of in vitro cultivation systems.

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Aceria guerreronis Keifer (Acari: Eriophyidae) is a major pest of coconut fruits (Cocos nucifera L.) in many countries of the Americas, Africa, and parts of Asia. Considerable attention has been given to studies of biological control agents of A. guerreronis. Proctolaelaps bulbosus Moraes, Reis and Gondim Jr. is a predator recently discovered in association with A. guerreronis. Nothing is known about its biology. The aim of this study was to determine suitable food sources for P. bulbosus, among items commonly found on coconut fruits, including A. guerreronis. Food sources evaluated included the mites A. guerreronis, Steneotarsonemus concavuscutum Lofego and Gondim Jr., and Tyrophagus putrescentiae (Schrank), the fungus Rhizopus aff. stolonifer (Ehrenb.) Vuill and coconut pollen; the mite Tetranychus urticae Koch was also included in the assessments, for being a commonly used prey for mass production and laboratory rearing of predatory mites. Proctolaelaps bulbosus was able to develop up to adulthood when fed A. guerreronis, R. aff. stolonifer and T. putrescentiae. It had the highest population growth rates when feeding on the former (R (o) = 17.5; r (m) = 0.392). These results indicate that A. guerreronis is the most suitable food for P. bulbosus among the possible food sources found on coconut fruits and that P. bulbosus can survive in the absence of eriophyid using R. aff. stolonifer as a food source.

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This study reports on the views of Primary Health Care (PHC) providers in Southeast Brazil on the use of alcohol and other drugs which reflect stigma, moralization, or negative judgment. Six hundred nine PHC professionals from the Brazilian states of Sao Paulo and Minas Gerais took part in the study. The majority (86.5%) of these professionals were female. Attitudes toward the use of alcohol and other drugs were evaluated in comparison to Hansen`s disease, obesity, depression, schizophrenia. HIV/AIDS, and tobacco use. The use of tobacco, marijuana/cocaine, and alcohol were the most negatively judged behaviors (p < 0.05). Nursing assistants and community health care workers demonstrated the severest judgment of alcohol use. In addition, marijuana/cocaine addicts and alcoholics suffered the highest rate of rejection by professionals. The hypothesis that the use of alcohol and other drugs is a behavior stigmatized by health professionals being confirmed, it is important to develop strategies for changing provider attitudes in order to provide a higher quality of service to these patients. This study is important as a first study among PHC professionals about social stigma of alcohol and other drugs users. (C) 2009 Elsevier Ltd. All rights reserved.

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To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.

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Fire is an important factor in several ecosystems, affecting plant population biology. Campos grasslands are under constant influence of disturbance, mostly grazing and fire. However, few studies evaluated the effect of fire on plant population biology of grassland species. Therefore, we aim to analyze the effect of fire on the population biology of four species, from different functional groups and regeneration strategies: Chaptalia runcinata (forb, resprouter, absence of belowground organ), Vernonia flexuosa (forb, resprouter, presence of rhizophore), Eupatorium ligulaefolium (shrub, resprouter, presence of xylopodium) and Heterothalamus psiadioides (shrub, obligate seeder). Seven plots were established in different sites in southern Brazil: frequently burned (FB) and excluded from fire since 6 years (E). All plots were subjected to controlled burns during summer. Before experiments, populations were sampled. Further observations were carried out after 90 and after 360 days of fire experiments. In addition, we counted the number of seedlings and resprouters recruited after fire. Heat shock experiments were conducted with two species (H. psiadioides and V. flexuosa), as well as the study of the bud bank of the following species: E. ligulaefolium and V. flexuosa. The obligate seeder species had all individuals killed by fire and established only after 1 year. Resprouters, however, showed new stems immediately after fire. E. ligulaefolium and V. flexuosa showed only vegetative regeneration from belowground organs and more individuals in excluded sites 1 year after the fire. The bud bank of E. ligulaefolium tended to be larger in excluded sites, whilst V. flexuosa showed an opposite result. High temperatures did not enhance nor kill seeds from both studied species. Vegetative regeneration was the most important strategy for all studied species, except for H. psiadioides, the obligate seeder species. Fire thus, plays an important role on population structure and demography, being also important for plant recruitment.

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P>Many hemoglobin-derived peptides are present in mouse brain, and several of these have bioactive properties including the hemopressins, a related series of peptides that bind to cannabinoid CB1 receptors. Although hemoglobin is a major component of red blood cells, it is also present in neurons and glia. To examine whether the hemoglobin-derived peptides in brain are similar to those present in blood and heart, we used a peptidomics approach involving mass spectrometry. Many hemoglobin-derived peptides are found only in brain and not in blood, whereas all hemoglobin-derived peptides found in heart were also seen in blood. Thus, it is likely that the majority of the hemoglobin-derived peptides detected in brain are produced from brain hemoglobin and not erythrocytes. We also examined if the hemopressins and other major hemoglobin-derived peptides were regulated in the Cpefat/fat mouse; previously these mice were reported to have elevated levels of several hemoglobin-derived peptides. Many, but not all of the hemoglobin-derived peptides were elevated in several brain regions of the Cpefat/fat mouse. Taken together, these findings suggest that the post-translational processing of alpha and beta hemoglobin into the hemopressins, as well as other peptides, is up-regulated in some but not all Cpefat/fat mouse brain regions.

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This paper presents an overview of the results obtained during the Joint Experiments organized in the framework of the IAEA Coordinated Research Project on `Joint Research Using Small Tokamaks` that have been carried out on the tokamaks CASTOR at IPP Prague, Czech Republic (2005), T-10 at RRC `Kurchatov Institute`, Moscow, Russia (2006), and the most recent one at ISTTOK at IST, Lisbon, Portugal, in 2007. Experimental programmes were aimed at diagnosing and characterizing the core and the edge plasma turbulence in a tokamak in order to investigate correlations between the occurrence of transport barriers, improved confinement, electric fields and electrostatic turbulence using advanced diagnostics with high spatial and temporal resolution. On CASTOR and ISTTOK, electric fields were generated by biasing an electrode inserted into the edge plasma and an improvement of the global particle confinement induced by the electrode positive biasing has been observed. Geodesic acoustic modes were studied using heavy ion beam diagnostics on T-10 and ISTTOK and correlation reflectometry on T-10. ISTTOK is equipped with a gallium jet injector and the technical feasibility of gallium jets interacting with plasmas has been investigated in pulsed and ac operation. The first Joint Experiments have clearly demonstrated that small tokamaks are suitable for broad international cooperation to conduct dedicated joint research programmes. Other activities within the IAEA Coordinated Research Project on Joint Research Using Small Tokamaks are also overviewed.

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Trehalase (EC 3.2.1.28) hydrolyzes only alpha, alpha`- trehalose and is present in a variety of organisms, but is most important in insects and fungi. Crystallographic data showed that bacterial trehalase has 0312 and E496 as the catalytical residues and three Arg residues in the active site. Those residues have homologous in all family 37 trehalases including Spodoptera frugiperda trehalase (0322, E520, R169, R227, R287). To test the role of these residues, mutants of trehalase were produced. All mutants were at least four orders of magnitude less active than wild type trehalase and no structural difference between these mutants and wild type enzyme were discernible by circular dichroism. D322A and E520 pH-activity profile lacked the alkaline arm and the acid arm, respectively, suggesting that D322 is the acid and E520 the basic catalyst. Azide increases E520A activity three times, confirming its action as the basic catalyst. Taking into account the decrease in activity after substitution for alanine residue, the three arginine residues are as important as the catalytical ones to trehalase activity. This clarifies the previous misidentification of an Arg residue as the acid catalyst. As far as we know, this is the first report on the functional identification residues important for trehalase activity. (C) 2010 Elsevier Ltd. All rights reserved.

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A phytochemical investigation of the leaves and stems of Peperomia obtusifolia (Piperaceae) yielded a new flavone C-diglycoside isoswertisin-4`-methyl-ether-2 ``alpha-L-rhamnoside (1), along with four known compounds: isoswertisin-2 ``alpha-L-rhamnoside (2), (+)-diayangambin (3), 2-episesalatin (4) and corchoionoside C (5). The structures of the two flavone C-diglycosides (1, 2) were elucidated on the basis of 1D and 2D NMR spectroscopy and MS spectrometric data. These flavones were evaluated by bioautographic assay against Cladosporium cladosporioides and C. sphaerospermum and showed weak antifungal activity.

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There is a little-noticed trend involving human immunodeficiency virus (HIV)-infected patients suspected of having tuberculosis: the triple-treatment regimen recommended in Brazil for years has been potentially ineffective in over 30% of the cases. This proportion may be attributable to drug resistance (to at least 1 drug) and/or to infection with non-tuberculous mycobacteria. This evidence was not disclosed in official statistics, but arose from a systematic review of a few regional studies in which the diagnosis was reliably confirmed by mycobacterial culture. This paper clarifies that there has long been ample evidence for the potential benefits of a four-drug regimen for co-infected patients in Brazil and it reinforces the need for determining the species and drug susceptibility in all positive cultures from HIV-positive patients.

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We describe and illustrate the venom apparatus and other morphological characters of the recently described Martialis heureka ant worker, a supposedly specialized subterranean predator which could be the sole surviving representative of a highly divergent lineage that arose near the dawn of ant diversification. M. heureka was described as the single species of a genus in the subfamily, Martialinae Rabeling and Verhaagh, known from a single worker. However because the authors had available a unique specimen, dissections and scanning electron microscopy from coated specimens were not possible. We base our study on two worker individuals collected in Manaus, AM, Brazil in 1998 and maintained in 70% alcohol since then; the ants were partially destroyed because of desiccation during transport to São Paulo and subsequent efforts to rescue them from the vial. We were able to recover two left mandibles, two pronota, one dismembered fore coxa, one meso-metapropodeal complex with the median and hind coxae and trochanters still attached, one postpetiole, two gastric tergites, the pygidium and the almost complete venom apparatus (lacking the gonostylus and anal plate). We illustrate and describe the pieces, and compare M. heureka worker morphology with other basal ant subfamilies, concluding it does merit subfamilial status.

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In 2000, an outbreak of sylvatic yellow fever possibly occurred in gallery forests of the Grande river in the Paraná basin in the northwestern region of São Paulo state. The aim of this study was to obtain information on the bionomics of Haemagogus and other mosquitoes inside tree holes in that area. Eighteen open tree holes were sampled for immature specimens. Adults were collected twice a month in the forest in Santa Albertina county from July 2000 to June 2001. The seasonal frequency of fourth instars was obtained by the Williams geometric mean (Mw), while the adult frequency was estimated either by hourly arithmetic or the Williams' means. Cole's index was applied to evaluate larval inter-specific associations. Among the ten mosquito species identified, the most abundant was Aedes terrens Walker followed by Sabethes tridentatus Cerqueira and Haemagogus janthinomys Dyar. Larval and adult abundance of these species was higher in summer than in winter. Although larval abundance of Hg. janthinomys peaked in the rainy season, correlation with rainfall was not significant. Six groups of larval associations were distinguished, one of which the most positively stable. The Hg. janthinomys and Ae. terrens association was significant, and Limatus durhamii Theobald was the species with most negative associations.

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To determine the presence of Kaposi sarcoma-associated herpesvirus (KSHV) and other serologic markers, we tested serum specimens of 339 Amerindians, 181 rural non-Amerindians, and 1,133 urban blood donors (13 Amerindians) in the Brazilian Amazon. High KSHV seroprevalence in children and inverse association with herpes simplex virus type 2 indicates predominant nonsexual transmission among Amerindians.