945 resultados para Reactive species of oxygen


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Wyeomyia forcipenis sp.n. is described from specimens caught in Jacarepaguá. State of Rio de Janeiro, Brazil. The male genitalia and the chaetotaxy of the pupa and larva are figured. This species is close to Wy. bourrouli (Lutz, 1905), being distinguished particularly by the shape of the hind plate of the phallosome.

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The male and female of Psychodopygus leonidasdeanei n.sp., (Diptera : Psychodidae) are described and illustrated from specimens collected in Shannon traps near Santarém, Pará State, Brazil. This species is a member of the squamiventris series and information is given on the distribution of the members of this series in Pará. A pictorial guide to separate the males and some females from others in the series is given.

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Otodistomum cestoides (van Beneden, 1871) (Azygiidae: Digenea) is reported for the first time from Psammobatis scobina and Raja flavirostris. The skates were caught off the coast of San Antonio, Chile.

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Culex siphanulatus, sp. n. is described from specimens collected in bromeliads of the coast of Rio de Janeiro State, Brazil. The description includes illustrations of female, male genitalia and chaetotaxy of pupa and larva. This species is easily distinguished from the others of subgenus Microculex and does not belong to any of the four series proposed for the grouping of its species.

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Oxygen uptake was studied during the establishment of cephalocaudal polarity in the very early chick embryo, i.e., 10 hr before (stage VI) and at laying (stage X). Oxygen fluxes in minute regions of the intact blastoderms were measured in vitro by scanning microspectrophotometry in the presence or absence of glucose. The oxygen consumption of the whole blastoderm remained constant (6 nmol O2 X hr-1) throughout the period studied, although the number of cells increased more than twofold. The regional oxygen fluxes varied from 0.41 to 1.13 nmol O2 X hr-1 X mm-2 at stage VI and from 0.42 to 0.70 nmol O2 X hr-1 X mm-2 at stage X. At stage VI, the oxygen flux in the center of the blastoderm was significantly higher than that in its periphery. This pattern remained evident when the values were corrected for cell number or for cytoplasmic volume. At stage X, there was a tendency for the oxygen fluxes to decrease from the posterior to the anterior regions of the area pellucida. Thus the pattern of oxidative metabolism in the late uterine embryos seems to change from radial to bilateral. This change of symmetry probably reflects the process of formation of the embryonic axis. In addition, the fact that the oxygen uptake was similar in the presence or absence of glucose suggests that early chick embryos metabolize essentially intracellular stores.

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Pygmy Shrews in North America have variously been considered to be one species (Sorex hoyi) or two species (S. hoyi and S. thompsoni). Currently, only S. hoyi is recognized. In this study, we examine mitochondrial DNA sequence data for the cytochrome b gene to evaluate the level of differentiation and phylogeographic relationships among eleven samples of Pygmy Shrews from across Canada. Pygmy Shrews from eastern Canada (i.e., Ontario, Quebec, New Brunswick, Nova Scotia, and Prince Edward Island) are distinct from Pygmy Shrews from western Canada (Alberta, Yukon) and Alaska. The average level of sequence divergence between these clades (3.3%) falls within the range of values for other recognized pairs of sister species of shrews. A molecular clock based on third position transversion substitutions suggests that these two lineages diverged between 0.44 and 1.67 million years ago. These molecular phylogenetic data. combined with a reinterpretation of previously published morphological data, are suggestive of separate species status for S. hoyi and S. thompsoni as has been previously argued by others. Further analysis of specimens from geographically intermediate areas (e.g., Manitoba. northern Ontario) is required to determine if there is secondary contact and/or introgression between these two putative species.

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The male adult of Culex (Melanoconion) anoplicitus, a new species from Southern Tropical Atlantic System of Brazil, South America, is described and illustrated. Identification may be made by characteristic morphological aspects of genitalia which are peculiar to this species.

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Three new species of Neotropical Sarcophagidae are described. Miltogrammatinae: Oebalia costarica sp. n (Costa Rica) and Senotainia trifida sp. n. (Chile), of which the latter is the first representative of the subfamily with a tripartite phallotreme. Sarcophaginae: Johnsonia woodorum sp. n. (Costa Rica, Panama).

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Four new species of Periscelididae are described from Brazil - Neoscutops cariri, sp. n., and Scutops marcgrafi sp. n., from the northern extreme of the Atlantic Forest, S. lopesi, sp. n., from southeastern Brazil, and S. goianiensis, from central Brazil. S. chapmani is herein synonymezed to S. fascipennis. A key is provided for the known species of Neoscutops and Scutops. A brief discussion is made about the possiblem phylogenetic relationships among the species of each of these two genera.

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A new species of Stylogaster is described from Roraima, Brazil. It belongs to the neglecta-group of species.

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Female and male of Dasybasis diaguita n. sp. from high area of NW of Argentina is described and illustrated.

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A key is given for the identification of females of all Holarctic species included into this genus, and keys are provided for distinguishing third instar larvae and puparia of two Palaeartic species. In addition to these, the description of the A. monachae (Kr.) female has been expanded.

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Several stylopized specimens were found among the Hymenoptera collection of the Instituto Oswaldo Cruz (Rio de Janeiro, Brazil). A paper by Kogan & Oliveira (1966) described the parasites of Polybia represented among those specimens. I describe herein the first neotropical species of the genus Crawfordia parasitizing species of Psaenithia (Andrenidae, Panurgini). The presence of vestigial thoracic segmentation of the female cephalothorax is a peculiar trait of this genus of Strepsiptera. Triungulinids are described in detail for the first time in this genus.