817 resultados para key characters


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Not more than four species of cestodes of the genus Echinococcus Rudolphi, 1801, are recognized as valid. The larval stage of at least three of them is able to develop in man, causing respective types of hydatid disease. Accurate characterization of these cestodes, including both larval and adult stages, is essential for identification, upon which depends development of methods for preventing infection of man and domestic animals. Because morphological characteristics of the larval cestodes may be modified according to the species of host in which they develop, identification should be based upon taxonomic characters of specimens from the respective natural hosts, which can be identified by means of ecological investigations in endemic areas in combination with controlled infection of experimental animals. The morphological and biological characteristics of the known species are discussed, and the two species most important to public health and economically--E. granulosus (Batsch, 1786) and E. multilocularis Leuckart, 1863--are distinguished. French résumé: Trois espèces de cestodes du genre Echinococcus Rudolphi, 1801 ont été identifiées: E. granulosus (Batsch, 1786); E. multilocularis Leuckart, 1863; et E. oligarthrus (Diesing, 1863). On n'a pas encore déterminé avec certitude s'il fallait leur adjoindre E. patagonicus Szidat, 1960. Ce dernier mis à part, tous ces ténias sont connus pour provoquer chez l'homme des formes spécifiques d'échinococcose hydatique; l'infestation par les larves de E. granulosus est également fréquente chez les ongulés domestiques et la répartition de ce cestode est presque cosmopolite. E. multilocularis est très largement répandu dans l'hémisphère nord, tandis que E. oligarthrus ne se trouve que dans le centre et le sud de I'Amérique. Pour définir des critères morphologiques qui permettent de distinguer avec précision les différentes espèces d'Echinococcus, il convient de prendre les spécimens sur leurs hôtes naturels, sinon l'évolution du stade strobilaire se trouve habituellement retardée et le stade larvaire présente une gamme étendue de variations morphologiques. Pour identifier les hôtes naturels, il faut étudier l'écologie dans les zones d'éndemicité, ainsi que les manifestations de l'infection contrôlée chez des animaux d'expérience. Le stade strobilaire des ténias peut présenter plusieurs caractères spécifiques importants qui concernent notamment la taille, le nombre et la répartition des testicules, la position du pore génital dans les segments gravides, la forme de l'utérus gravide et, dans certains cas, la taille et la forme des crochets du rostre. La structure de la larve normalement développée est caractéristique de chacune des trois espèces relativement bien connues. Les caractéristiques biologiques jouent également un rôle important dans la différenciation de ces cestodes. Au stade larvaire, le laps de temps nécessaire au développement des scolex infectants est directement fonction de la durée de vie de l'hôte intermédiaire. La larve de E. multilocularis présente des scolex infectants dès le deuxième ou le troisième mois, alors qu'ils n'apparaissent qu'au bout d'un ou deux ans chez la larve de E. granulosus. Un tableau donne la liste comparative des caractéristiques taxonomiques qui permettent de faire la distinction entre ces deux espèces.

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Objectives: Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials: We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions: We have demonstrated, using immunohistochemistry and reverse transcription-polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin beta 1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction.

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Based on the morphology of workers, gynes and males, we revise the taxonomy of nominal taxa traditionally included by authors in the fungus-growing ant genus Mycetophylax. Our results indicate that Mycetophylax Emery (Myrmicocrypta brittoni Wheeler, 1907, type species, by designation of Emery, 1913; junior synonym of Cyphomyrmex conformis Mayr, 1884 by Kempf, 1962) includes M. conformis, M. simplex (Emery, 1888), and M. morschi (Emery, 1888) new combination (formerly in Cyphomyrmex), with several synonymies. Mycetophylax bruchi (Santschi, 1916) does not belong to the same genus and is diagnosed, in addition to other characters, by a psammophore arising at the anterior margin of the clypeus. For this species we are resurrecting from synonymy Paramycetophylax Kusnezov, 1956 (Mycetophylax bruchi as type species, by original designation, with M. cristulatus as its new synonym). Myrmicocrypta emeryi Forel, 1907 is the only attine in which females lack the median clypeal seta and have the antennal insertion areas very much enlarged and anteriorly produced, with the psammophore setae arising from the middle of the clypeus and not at its anterior margin as in Paramycetophylax. Notwithstanding its inclusion in Mycetophylax by recent authors, it is here recognized as belonging to a hitherto undescribed, thus far monotypic genus, Kalathomyrmex new genus (Myrmicocrypta emeryi as its type species, here designated). We redescribe workers, gynes and males of all species in the three genera and describe for the first time gynes of Mycetophylax conformis and M. simplex, males of M. simplex and M. morschi, and gynes of P. bruchi. Furthermore we present a key to the workers of the taxa treated here (most formerly included under the name Mycetophylax), a key to workers of the Mycetophylax in the revised sense, SEM pictures and high resolution AutoMontage(C) photographs of the species, along with maps of collection records and a summary of biological observations.

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Nycterilampus Montrouzier, 1860, from Oceania, is removed from junior synonymy with Tetrigus Candeze, 1857, and is redescribed and revalidated. The genus includes two species, N. lifuanus Montrouzier, 1860, and N. velutinus Fleutiaux, 1891 both from New Caledonia. A comparative study of the morphological characters of males and females, including the reproductive organs of the Nycterilampus species and Tetrigus parallelus Candeze, 1857 (type-species) is presented. A key to Nycterilampus species and their separation from Tetrigus parallelus is given.

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Two new species of Toxophora Meigen are described and illustrated-T. paulistana sp. nov. (Neotropical) and T. azteca sp. nov. (Nearctic and Neotropical). An identification key to the New World species is also presented. Morphological differences between populations of T. aurea Macquart (1848) are recorded, illustrated and added to the key. The new species are easily recognized by: scape with long, yellow scales laterally; presence of yellow scales on mesonotum margins; posterior margin of mesonotum with a pre-scutellar pair of setae; and yellow scales forming thin bands on posterior margins of abdominal tergites in T. paulistana sp. nov., and scape entirely covered with long dark-brown scales and yellow scales forming a broad, longitudinal stripe on center of abdominal tergites III-VII in T. azteca sp. nov.

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Three new species of Triplonychus Candeze, T. cruspinosus sp. nov., T. crassifemoris sp. nov. and T. tibialatus sp. nov., and a new species of Globothorax Fleutiaux, G. latidens sp. nov., from Brazil are described. Illustrations, photographic and SEM images are presented. A review of the diagnostic generic characters and a key to the species of Triplonychus and Globothorax from Brazil are also given.

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Generic characters of Irundisaua Martins & Galileo, 2005 are expanded (antennal formula, width of prosternal process inferior or equal to the diameter of procoxa, protibia enlarged and flattened) and two species are transferred from Acanthoderes Audinet-Serville, 1835: I. forsteri (Tippmann, 1960) comb. nov from Peru and Brazil (Amazonas) and I. ucayalensis (Tippmann,1960) comb. nov from Ecuador, Peru and Brazil (Amazonas).Three new genera are described: (1) Catuana gen. nov., type species, C. spinicornis (Tippmann, 1960) comb. nov, characterized by the mesosternal tubercle; (2) Mundeu gen. nov, type species, M. maculicollis (Bates, 1861) comb. nov, with rounded sides of protorax and expanded protibiae; (3) Urangaua gen. nov, with eyes divided and finelly granulated, length of antenomeres III-IV subequal to V-XI; the genus is proposed of two species: U. analis Melzer, 1935 comb. nov, type species, and U. subanalis (Zajciw,1964) comb. nov. A key to the species of Urangaua is added.