RESUMO
Ultrastructural studies of spermiogenesis and sperm morphology have found many characters that are likely to provide clues to the phylogeny of the Platyhelminthes. However, the lack of information on many free-living groups has been a limiting factor. There is a single description of the spermatogenesis and spermatozoa in a Phaenocora species, namely P. anomalocoela, therefore a similar analysis was made in Phaenocora unipunctata to compare the intrageneric variation of sperm ultrastructure and spermatogenesis in the Neotyphloplanida. The comparison of the two Phaenocora species shows that several characters have the potential to be relevant to hypothesize phylogenetic relationships at different taxonomic levels. The presence of superficially incorporated axonemes outside the ring of cortical microtubules in the mature sperm cell, resulting from the fusion of the axonemes with the median cytoplasmic process during spermiogenesis, as well as the presence of a constant number of microtubules in the different regions of the spermatozoon, seem to constitute apomorphies of the genus Phaenocora. Furthermore, the presence of an axonemal spur, the compression of cortical microtubules by the rotation of the basal bodies during spermiogenesis, and the presence of a connection between the nucleus and the plasma membrane in the mature spermatozoon, support previous proposals that these characters are apomorphies of Dalytyphloplanida. The comparison of spermatogenesis and spermatozoa of P. unipunctata and P. anomalocoela demonstrates that studying intrageneric variation can give valuable insights into the significance of many characters proposed for phylogenetic studies of the Rhabdocoela.
Assuntos
Platelmintos/ultraestrutura , Espermatogênese/fisiologia , Espermatozoides/ultraestrutura , Animais , Masculino , Filogenia , Especificidade da EspécieRESUMO
Many species of turbellarians (Platyhelminthes) are known to live associated with other organisms, especially invertebrates, as commensals or parasites. The family Graffillidae (Rhabdocoela) includes two genera that parasitize mollusks, Graffílla and Paravortex. Within the latter genus, six species were described as associated with mollusks. In other instances, unnamed Paravortex species were mentioned as parasites of other bivalves and of the body surface of fishes. In the present work, a new Paravortex species that was found in the intestine of Mesodesma mactroides from the Atlantic coast of Uruguay is described. In addition, a bibliographical revision of the known Paravortex species with their respective hosts, location, and distribution is made. Paravortex nicolli, described by Szidat for the Argentinean coast, is mentioned for the first time after the original description, and the authorship and date of description of Paravortex tapetis Noury-Sraïri 1989 are elucidated.
Assuntos
Bivalves/parasitologia , Turbelários/anatomia & histologia , Turbelários/isolamento & purificação , Animais , Transtornos do Desenvolvimento Sexual , Intestinos/parasitologia , Turbelários/classificação , UruguaiRESUMO
To date, the monospecific Dendrorchis is represented by D. neivai, reported from Brazil and parasitizing Brycon lundi. Dendrorchis retrobiloba n. sp. is described from the swim bladder of Astyanax fasciatus from Cañada del Dragón stream in Montevideo, southern Uruguay (34 degrees 47'S, 56 degrees 14'W), and the emended diagnosis of Dendrorchis is given. The diagnosis of Dendrorchis has been modified to include the following characters: Phyllodistominae with flattened body, wider in the region posterior to acetabulum. Intestinal ceca sinuous or not. Testes branched or with superficial lobes. Ovary with deep or superficial lobes. Seminal receptacle present or absent. Vitellaria ellongate or pyriform. Uterus extends to posterior region and to portion of body anterior to acetabulum. Eggs oval, variable size, thin-shelled, without opercula. Dendrorchis retrobiloba n. sp. differs from D. neivai by having pyriform vitellaria, ovary larger than the testes and not deeply lobed, wider distribution of the uterus, smaller egg size, testes with superficial lobes, oral sucker wider than the acetabulum, shorter esophagus, 2 terminal lobes at the posterior end of the body, and much smaller body length. Despite being found in different hosts, both species of Dendrorchis parasitize the swim bladder of freshwater Characidae.
Assuntos
Doenças dos Peixes/parasitologia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Peixes , Trematódeos/anatomia & histologia , Infecções por Trematódeos/parasitologia , UruguaiRESUMO
This paper provides the first description of the Haswell cells at the ultrastructural level, as well as giving an insight into their function. Two species of Temnocephalidae were studied, Temnocephala iheringi and T. haswelli. Haswell cells are identical in both species, and their structure indicates that they have a secretory function. They are highly interdigitated with parenchymal cells and are usually joined to them by cup-like desmosomes. Nuclei are irregular, with a honeycomb structure and perichromatin granules. The most prominent organelle is granular endoplasmic reticulum, which is typically arranged in concentric rings that usually encircle a conspicuous Golgi complex. Secretion bodies are secreted via projections of the Haswell cells that reach the surface in the anterior portion of the body and in the tentacles. Distinct pores with a size and distribution consistent with the TEM observations were seen under SEM in these regions.
Assuntos
Turbelários/citologia , Animais , Núcleo Celular/ultraestrutura , Retículo Endoplasmático Rugoso/ultraestrutura , Complexo de Golgi/ultraestrutura , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Turbelários/fisiologia , Turbelários/ultraestruturaRESUMO
La población femenina en edad fértil de la comuna de Pichidegua es de 3.594 mujeres de las cuales 955 (26,5%) se encuentran en control de natalidad. De estas últimas, 920 (96,4%) son portadoras de dispositivos intrauterinos y 35 (3,6%) toman anticonceptivos orales. Entre abril de 1982 y mayo de 1984 se produjeron 39 embarazos en el grupo de las 920 portadoras de dispositivos (23 T de cobre y 16 Lippes). El trabajo analiza la distribuición por grupos de edad de estas 39 pacientes; su paridad; la edad gestacional a su ingreso a control; el tiempo de uso previo del dispositivo; la evolución del embarazo. Esto último fue más favorable cuando se extrajo precozmente el dispositivo