101 resultados para biological species

em Scielo Saúde Pública - SP


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The use of wild oat races in artificial hybridization with cultivated oat (Avena sativa L.) has been used as a way of increasing the variability. This work aimed to identify the variability for plant height and flowering date of groups of cultivated oat genotypes, wild introductions of A. fatua L. and segregating populations of natural crosses between A. sativa and A. fatua. Wide genetic variability was observed for both traits in the groups and between them. The wild group of A. fatua L. showed high plants with early maturity, but in the segregating group there was reduced plant height and early maturity. The wild introductions of A. fatua L. studied in this work can be used in oat breeding programs to increase genetic variability by transferring specific characters into the cultivated germ plasm.

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A generalized comprehensive scheme concerning the movement of materials into living cells and tissues is presented. It is designed for use by investigators and teachers who, is assumed, have a previous knowledge of the subject as well as familiarity with previously published literature on the subject. Footnotes to figure 2 X = a constituent component material, arising from extermal sources or through metabolism, capable of migration under favorable conditions. e, i, ec, ic, mc = subscripts indicating location. oC = oxidized cytoplasmic constituents specifically concerned in unidirectional (here invardly directed), diffetial translocation of a particular material X. rC = reduced cytoplasmic constituents specifically concerned. XF = specific free energy (2) of a constituent component in in external or internal phases or in cytoplasm. D = diffusion (4). EA = exchange adsorption (4). MA= metabolic accumulation (4), CI = differentially characteristic cytoplasmic interaction (4) between oC and X, determined by the genetic constitution of the biological species. ▬▬▬>= migration, where permeability to the material involved is relatively high; and ~~~~->, where relatively low. <▬▬▬>= chemical reactions. ▬▬▬>= energy changes of X; diffusion is characteristically with the direction in which the concentration or activity of the constituent decreases, exchange adsorption may be with or against the direction of concentration or activity decrease.

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Nitric oxide (NO·) has been identified as a principal regulatory molecule of the immune system and the major cytotoxic mediator of activated immune cells. NO· can also react rapidly with a variety of biological species, particularly with the superoxide radical anion O2·- at almost diffusion-limited rates to form peroxynitrite anion (ONOO-). ONOO- and its proton-catalyzed decomposition products are capable of oxidizing a great diversity of biomolecules and can act as a source of toxic hydroxyl radicals. As a consequence, a strategy for the development of molecules with potential trypanocidal activities could be developed to increase the concentration of nitric oxide in the parasites through NO·-releasing compounds. In this way, the rate of formation of peroxynitrite from NO· and O2·- would be faster than the rate of dismutation of superoxide radicals by superoxide dismutases which constitute the primary antioxidant enzymatic defense system in trypanosomes. The adenosine transport systems of parasitic protozoa, which are also in certain cases implicated in the selective uptake of active drugs such as melarsoprol or pentamidine, could be exploited to specifically target these NO·-releasing compounds inside the parasites. In this work, we present the synthesis, characterization and biological evaluation of a series of molecules that contain both a group which would specifically target these drugs inside the parasites via the purine transporter, and an NO·-donor group that would exert a specific pharmacological effect by increasing NO level, and thus the peroxynitrite concentration inside the parasite.

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The behavior of T. cruzi strains from S. Felipe - BA (19 SF, 21 SF and 22 SF) classified as Type II Zymodeme 2, was investigated after passage through the authoctonous (P. megistus) and foreign vectors (T. infestans and R. prolixus). For each strain Swiss mice were infected: I - with blood forms (control); II - with metacyclic forms (MF) from P. megistus; III - with MF from T. infestans; IV - with MF from R. prolixus. Inocula: MF from the three species of triatomine, 60 to 120 days after feeding in infected mice, adjusted to 10 4. Biological behavior in mice (parasitemia, morphology, mortality, virulence and pathogenicity) after passage through triatomine was compared with data from the same strain in control mice. Isoenzymic electrophoresis (ASAT, ALAT, PGM, GPI) were also performed after culture into Warren medium. The three strains maintained the isoenzyme profiles (zymodeme 2), in the control groups and after passages through different species of triatomine. Biological characterization disclosed Type II strains patterns for all groups. An increased virulence was observed with the 22 SF strain isolated from P. megistus and T. infestans and higher levels of parasitemia and predominance of slender forms in mice inoculated with the 19 SF and 21 SF from these same species. Results indicate that the passage through the two species T. infestans and P. megistus had a positive influence on the virulence of the regional strains of S. Felipe, regardless of being autocthonous (P. megistus) or foreign to the area (T. infestans).

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The purpose of this work was to determine the diversity and population fluctuations of calliphorid flies in the Biological Reserve of Tinguá (ReBio-Tinguá), Nova Iguaçu, state of Rio de Janeiro, Brazil and to correlate their occurrence with the environmental variables of temperature, rainfall and relative air humidity. Specimens of Diptera were collected monthly between June 2002 and January 2005 using four traps placed at four points along a trail and exposed for 48 hours. The traps were baited with sardines and the trapped insects were stored in 70% alcohol. It was collected 8,528 calliphorids, thirteen species were identified among the blowflies including Laneela nigripes Guimarães 1977, Chrysomya megacephala (Fabricius, 1794), C. albiceps (Wiedemann, 1819), C. putoria (Wiedemann, 1830), Chloroprocta idioidea (Robineau-Devoidy, 1830), Cochliomyia macellaria (Fabricius, 1775), Hemilucilia semidiaphana (Rondani, 1850), H. segmentaria (Fabricius, 1805), Lucilia eximia (Wiedemann,1819), L. cuprina (Wiedemann, 1830), Paralucilia pseudolyrcea (Mello, 1969), Mesembrinella sp. and Eumesembrinella pauciseta (Aldrich, 1922). No significant correlation was found between the abundance of blowflies and the temperature and relative air humidity. Only C. megacephala and C. albiceps showed a positive and significant correlation with rainfall. An analysis of grouping by month (UPGMA) revealed no seasonal difference in the composition of the community, indicating that the community of calliphorid flies is probably more influenced by the ecological niches occupied by each species than by the seasons of the year.

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Litargus tetraspilotus LeConte, 1856 was collected feeding on Oidium sp. (Fungi, Ascomycota, Erysiphaceae) associated with fruit trees. This is the first time L. tetraspilotus is recorded in Brazil, totaling three species of Mycetophagidae for this country. This study aims to provide a complementary description of this species based on new characters and to present information on its life cycle under laboratory conditions and fluctuation in population in the field. During the period of inventories between July 2004 and August 2006, about every fifteen days, a total of 565 specimens of L. tetraspilotus were collected, with the highest abundance found on citrus plants, with values differing significantly between the two years. The population levels differed between the seasons; spring had the greatest abundance and autumn the least. There was a significant positive correlation of L. tetraspilotus abundance with rainfall and relative humidity. Mycetophagidae, as well as other mycophagous families of Brazilian coleopterans, are barely studied, warranting further future studies of their bioecology and systematics.

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Aleiodes Wesmael is the most diverse rogadine genus, with koinobiont endoparasitic development in Lepidoptera caterpillars resulting in mummification of the host remains. Aleiodes japi sp. nov. is described and illustrated. Type specimens of the new species were reared from Physocleora grosica and Ischnopteris sp. (Lepidoptera, Geometridae, Ennominae) larvae. Host larvae were collected on Alchornea triplinervia (Euphorbiaceae) at the Reserva Biológica Municipal da Serra do Japi, Jundiaí, São Paulo, Brazil. This is the second species of circumscriptus/gastritror group described from Brazil.

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The present work is a thorough investigation of the degree of reproductive isolation between Meccus mazzottii and Meccus longipennis, Meccus picturatus, Meccus pallidipennis and Meccus bassolsae, as well as between M. longipennis and M. picturatus. We examined fertility and segregation of morphological characteristics in two generations of hybrids derived from crosses between these species. The percentage of pairs with (fertile) offspring was highest in the set of crosses between M. longipennis and M. picturatus, and lowest between M. mazzottii and M. picturatus. Most first-generation (F1) individuals from crosses involving M. mazzottii were morphologically similar to this species, while only F1 x F1 progeny of parental crosses between M. mazzottii and M. longipennis had offspring second generation that looked like M. mazzottii. The results indicate that different degrees of reproductive isolation apparently exist among the species of the Phyllosoma complex examined in this study. The biological evidence obtained in this study does not support the proposal that M. longipennis and M. picturatus are full species. It could indicate on the contrary, that both could be considered as subspecies of a single polytypic species. On the other hand, biological evidence supports the proposal that M. mazzottii is a full species.

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The degree of reproductive isolation between Meccus phyllosomus and the remaining five species of the genus Meccus, as well as between Meccus bassolsae and Meccus pallidipennis, Meccus longipennis and Meccus picturatus, was examined. Fertility and the segregation of morphological characteristics were examined in two generations of hybrids from crosses between these species. The percentage of couples with offspring (fertile) was high in the vast majority of sets of crosses, with the exception of that between ♀M. phyllosomus and ♂Meccus mazzottii. In sets of crosses involving M. bassolsae specimens, no first-generation (F1) individuals were morphologically similar to M. bassolsae, but instead shared the morphology of the other parental species. A similar phenomenon was observed in most sets of crosses involving M. phyllosomus. These results indicated that different degrees of reproductive isolation exist among the species of Meccus involved in this study. The biological evidence obtained in this study does not support the proposal that M. bassolsae is a full species. It could indicate that, on the contrary, it should be considered a subspecies of a single polytypic species. The biological evidence does support the proposal that M. phyllosomus is a full species.

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A new Cervellus species is described from Brazil. The male to this genus is described for the first time as well its cocoon is illustrated. The specimens parasitize the papaya borer weevil Pseudopiazurus obesus (Boheman, 1838) (Coleoptera, Curculionidae) associated with Carica papaya Linnaeus, 1753 (Caricaceae) at Rio Grande do Norte and Bahia Brazilian States.

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Green manuring is recognized as a viable alternative to improve nutrient cycling in soils. The aim of this study was to evaluate the phytomass production and nutrient accumulation in shoots of the summer green manures jack bean [Canavalia ensiformis (L.) DC.], dwarf pigeon pea (Cajanus cajanvar var. Flavus DC.), dwarf mucuna [Mucuna deeringiana (Bort) Merr] and sunn hemp (Crotalaria juncea L.), under nitrogen fertilization and/or inoculation with N-fixing bacteria. A split plot design was arranged with the four Fabaceae species as main plots and nitrogen fertilization (with and without) and inoculation with diazotrophic bacteria (with and without) as the subplots, in a 2² factorial. The experiment was arranged as a randomized complete block design with four replications. In the conditions of this trial, the sunn hemp had the highest production of shoot phytomass (12.4 Mg ha-1) and nutrient accumulation, while the dwarf mucuna had the lowest production of shoot phytomass (3.9 Mg ha-1) and nutrient accumulation. The results showed no effect of nitrogen fertilization or inoculation with N-fixing bacteria on the production of shoot phytomass and nutrient accumulation, except for inoculation without nitrogen fertilization, resulting in greater P accumulation (p <0.05) in the sunn hemp and greater Zn and Mn accumulation in the dwarf mucuna. These findings indicate that N fertilization or inoculation with N2-fixing bacteria for Fabaceae are low efficiency practices in the edaphoclimatic conditions of this study.

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Hamster inoculated intraperitoneally with 1 x 10(7) parasites of L. donovani and L. major-like of the New World were studied in groups of 15, 30, 60 and 90 days of infection. The parasite load and density showed progressive increase with the evolution of the infection and was higher in the L. donovani groups than in the L. major-like groups. The L. major-like groups showed parasite density higher in the spleen than in the liver and was similar in both organs in L. donovani groups. The histopathology showed a diffuse marked hyperplasia and hypertrophy of the reticuloendothelial system with high parasitism in the L. donovani groups while there was focal involvement of these organs in L. major-like groups, forming nodules of macrophages that were scantly parasitised. The biological behaviour could be useful in the preliminary studies of Leishmania strain in regional laboratories and understanding the histopathology of lesions caused by different leishmania species.

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INTRODUCTION: Triatoma pseudomaculata and T. wygodzinskyi (Hemiptera: Reduviidae: Triatominae) are two Brazilian vectors of Chagas disease. The first is an arboricolous species in sylvatic environment and considered a vector of T. cruzi in peridomestic structures; the second, a rupicolous species in the wild environment of no epidemiological importance. In order to test the assumption that sister species share biological traits, comparative studies of their development cycle and blood ingestion were conducted. METHODS: Eggs laid by five field females of each species were randomly selected. The nymphs were observed daily and fed on mice weekly. The time required to pass through the different stages to adulthood was recorded in days. The triatomines were weighed individually before and after feeding. The mortality rate according to each nymphal stage was calculated. RESULTS AND CONCLUSIONS: Analysis of the results shows that they display only minor biological differences even though they exhibit a distinct ecology. This suggests that the biological traits are important criteria to determine the relationship between species.

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INTRODUCTION: Visceral leishmaniasis presents urban behavior in some Brazilian cities, with domestic dogs as the main infection source. In Cuiabá, MT, canine visceral leishmaniasis was diagnosed and characterized as recommended by the Ministry of Health. METHODS: Biological samples from suspected canine carriers were analyzed by the isoenzyme electrophoresis technique. The 6PGDH enzyme and reference strain IOC/L0566 (MHOM/BR/1975/M2903) of Leishmania (Leishmania) infantum was used as one of the controls. RESULTS: Electrophoresis analysis revealed that the canine isolates belonged to the species L. (L.) infantum. CONCLUSIONS: The authors emphasize the importance of species characterization, particularly in areas of mixed infection like Cuiabá.

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Introduction Biological collections are depositories of information on different species and contribute to the knowledge, protection, conservation and maintenance of biodiversity. Methods A list of triatomine species currently included in the Collection of Chagas Disease Vectors (FIOCRUZ-COLVEC) was prepared from the database made available by the Reference Center on Environmental Information. Results COLVEC curatorship houses 4,778 specimens of triatomines, of which 811 come from other American countries (Argentina, Bolivia, Colombia, Costa Rica, the United States of America, Guatemala, Mexico, Peru, Uruguay and Venezuela) and 3,967 are autochthonous from Brazil. Altogether, 56 species of Chagas disease vectors are represented in the COLVEC: two species of the Tribe Cavernicolini Usinger, 1944; fifteen species of the tribe Rhodniini Pinto, 1926, of which 12 are of the genus Rhodnius and 3 are of the genus Psamolestes; and 39 species of the tribe Triatomini Jeannel, 1919, represented by the genus Dipetalogaster, two species of the genus Eratyrus, two of the genus Meccus, seven of the genus Panstrongylus and 27 of the genus Triatoma. Conclusions This list provides important data on the diversity of triatomines currently included in COLVEC, including the expanded area of Panstrongylus lutzi occurrence in the municipalities Pirapora and Januária, State of Minas Gerais. The maintenance and expansion of the collection ensures the preservation of biodiversity and further studies.