oalib
Search Results: 1 - 10 of 72 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /72
Display every page Item
New Virgulid Cercaria (Trematoda, Lecithodendroidea) from the Mollusk Melanopsis praemorsa (Melanopsidae) from Azerbaijan Water Bodies. Morphology and Chaetotaxy of Cercaria agstaphensis 11
A. A. Manafov
Vestnik Zoologii , 2011, DOI: 10.2478/v10058-011-0007-4
Abstract: An illustrated morphological description with chaetotaxy and differential diagnosis of the new form of virgulid cercaria — Cercaria agstaphensis 11 from freshwater prosobranchial mollusks Melanopsis praemorsa (Linnaeus, 1758) are given. Special attention is paid to the tegument armament, the structure of glandular apparatus, excretory system, digestive system, the structure of the sensory apparatus and other larval morphological characters.
Molecular Phylogeny and Estimated Time of Divergence in the Central European Melanopsidae: Melanopsis, Fagotia and Holandriana (Mollusca: Gastropoda: Cerithioidea)
Marcin Smoleń , Andrzej Falniowski
Folia Malacologica , 2009, DOI: 10.2478/v10125-009-0001-4
Abstract: Three European melanopsids: Melanopsis parreyssii (Philippi, 1847) from Ochiul Mare (Romania), Fagotia acicularis (A. Férussac, 1828) from a spring near Crisul Negru (Romania), and Holandriana holandri (C. Pfeiffer, 1828) from Lake Skutari (Montenegro), as well as Melanopsis costata Oliver, 1804 from Iraq, are considered is this paper. Eight partial sequences of ribosomal 18S, and seven of mitochondrial COI were analysed. Maximum likelihood trees based on 18S confirm the placement of the Melanopsidae within the Cerithioidea, as well as the monophyly of the latter group. The COI-based tree confirms the placement of the Melanopsidae within the Cerithioidea, but does not confirm the monophyly of either Melanopsidae or Cerithioidea. The results suggest that Fagotia should be synonymised with Melanopsis, Holandriana is a distinct genus, and Melanopsis costata is not congeneric with M. parreyssii. The application of molecular clock, with one point calibration for COI for the Hydrobiidae, estimated the times of divergence as 2.53±0.56 Mya for M. parreyssii and F. acicularis, 9.49±1.67 Mya for M. parreyssii and H. holandri, and 10.71±1.88 Mya for F. acicularis and H. holandrii. 2.5 Mya coincides with the beginning of the glacial period in Europe, and 8-12 Mya was the time when Lake Pannon covered the largest area.
Studies on Cercariae from Kuwait Bay. XI. Description and surface topography of Cercaria kuwaitae XI sp.n. (Digenea: Echinostomatidae)
Abdul-Salam, J;Sreelatha, BS;
Memórias do Instituto Oswaldo Cruz , 1999, DOI: 10.1590/S0074-02761999000600007
Abstract: a new echinostome cercaria, cercaria kuwaitae xi sp.n., from the prosobranch gastropod cerithidea cingulata (gmelin) from kuwait bay is described. the new cercaria is characterized by 23 collar spines and primary excretory tubules with distinct diverticula. the cercaria encysts in the snail host and is similar to those of acanthoparyphium sp. the surface topography of the redia, cercaria and metacercarial cyst wall is studied by scanning electron microscopy. this is the first echinostome cercaria to be recorded in a gastropod from the arabian gulf region.
Studies on Cercariae from Kuwait Bay. XI. Description and surface topography of Cercaria kuwaitae XI sp.n. (Digenea: Echinostomatidae)
Abdul-Salam J,Sreelatha BS
Memórias do Instituto Oswaldo Cruz , 1999,
Abstract: A new echinostome cercaria, Cercaria kuwaitae XI sp.n., from the prosobranch gastropod Cerithidea cingulata (Gmelin) from Kuwait Bay is described. The new cercaria is characterized by 23 collar spines and primary excretory tubules with distinct diverticula. The cercaria encysts in the snail host and is similar to those of Acanthoparyphium sp. The surface topography of the redia, cercaria and metacercarial cyst wall is studied by scanning electron microscopy. This is the first echinostome cercaria to be recorded in a gastropod from the Arabian Gulf region.
Schistosoma mansoni: the effect of dexamethasone on the cercaria-schistosomulum transformation, in vivo
Melo, Alan Laue de;Hermeto, Marco Victor;Bicalho, Rosilene Siray;Vargas, Ant?nio Pedro;Favaretto, Fábio Júnior Oliveira;Pereira, Leógeues Horácio;
Revista do Instituto de Medicina Tropical de S?o Paulo , 1994, DOI: 10.1590/S0036-46651994000100014
Abstract: treatment with dexamethasone (dms) in the early phases of the experimental schistosoma mansoni infection causes an indirect effect on the cercaria-schistosomulum transformation process. this is observed when naive albino mice are treated with that drug (50 mg/kg, subcutaneously) and infected intraperitonealy 01 hour later with about 500 s. mansoni cercariae (le strain). an inhibition in the host cell adhesion to the larvae, with a simultaneous delay in the cercaria-schistosomulum transformation, is observed. this effect is probably due to a blockade of the neutrophil migration to the peritoneal cavity of mice, by an impairment of the release of chemotactic substances. such delay probably favors the killing of s. mansoni larvae, still in the transformation process, by the vertebrate host defenses, as the complement system.
Cercaria of the Trematode Plagiorchis Mutationis (Trematoda, Plagiorchiidae) from the Pond Snails, Lymnaea Stagnalis, in Ukraine
O. P. Zhytova
Vestnik Zoologii , 2010, DOI: 10.2478/v10058-010-0022-x
Abstract: Morphological characteristics and measurements of Plagiorchis mutationis Panova, 1927 cercaria found for the first time in the intermediate host, pond snail Lymnaea stagnalis in Ukraine are given.
THE EFFECT OF SCHISTOSOMA MANSONI CERCARIA INFECTION AND TREATMENT WITH NIRIDAZOLE ON TESTICULAR HISTOLOGY OF THE MICE.
SYLVNUS JOSIAH DAFUR, PATRICIA MANKO LAR
African Journal of Clinical and Experimental Microbiology , 2003,
Abstract: The testicular histology of mice infected with Schistosoma mansoni (S.mansoni) cercaria and treated with Niridazole was examined. The results reveal that infection of mice with Schistosoma mansoni cercariae resulted in distortion of the testicular cyto-architecture including disruption of spermatogenesis as shown by the absence of spermatozoa in the lumen of the sominiferous tubule and distruction of the inter-tubular connective tissue of the infected mice. These changes were reversed to normalcy following two-course treatment of the infected mice with Niridazole after five weeks. (Af. J. of Clinical and Experimental Microbiology: 2003 4(1): 2-5)
Adhesion of Cercaria (Larva of Helminth Parasites) to Host by Lectins- Carbohydrates Bonds as a Model for Evaluation of Schistosoma Entrance Mechanisms in Cercarial Dermatitis
A Farahnak,N Dabagh
Iranian Journal of Public Health , 2008,
Abstract: Background: Cercariae (larva of helminth parasites) are covered by a thick glycocalyx coat, which serves as an osmotic protection during their free existence, and contain carbohydrates conjugated as glycoproteins, glycolipids and mucopolysaccharides. Although, limited studies have been made on life cycle of cercariae from fresh water snails, however, carbohydrate studies on cercariae have not been done in Iran so far. This study was made to determine the cercariae specifications from Lymnaea gedrosiana and evaluation of surface carbohydrates as receptors for host lectins in a host-parasite relationship system as a model in human schistosomiasis including cercarial dermatitis in Khuzestan Province. Methods: For this purpose, snails were collected from Dezful region in Khuzestan Province and cercariae were obtained by shedding method and identified by valuable keys. Experimental infection was established in the Culex pipiens (Culicidae mosquitoes) larvae for further identification and mode of adhesion. To detect the mode of adhesion, surface carbohydrates of cercariae were detected by lentil (Lens culinaris) lectins. Results: Examined snails were infected with xiphidiocerceria of trematodes and metacercariae were obtained from Culex pipiens. Also, Mannose monosaccharides- CH2OH (CHOH) 4CHO - were detected particularly on the glands of cercariae. Conclusion: Adhesion of cercariae to their host by lectins-carbohydrates bonds is the first stage of host-parasite relationship. This phenomenon could be happened for animal schistosome's cercaria in cercarial dermatitis.
A combined proteomic and immunologic approach for the analysis of Schistosoma mansoni cercariae and adult worm protein extracts and the detection of one of the vaccine candidates, Sm28GST, from a Venezuelan parasite isolate Aproximación al análisis proteómico e inmunológico de extractos proteicos de cercaria y verme adulto de Schistosoma mansoni y detección de uno de los candidatos a vacuna, Sm28GST, de un aislado venezolano
Sandra Losada,Laurence Sabatier,Philippe Hammann,Christelle Guillier
Investigación Clínica , 2011,
Abstract: Understanding the mode of Schistosoma mansoni larval invasion and the mechanism of immune evasion utilized by larvae and adult worms is essential for a rational development of vaccines or drugs to prevent or cure the disease. This parasite has a very complex molecular organization in all parasite stages, and identifying the major parasite proteins would give clues to schistosome metabolism and to the interaction of the parasite with the host immune system. Our goal was the evaluation of the protein parasite repertoire using a proteomic approach, and the characterization of protein extracts from two different parasite stages of a Venezuelan isolate, such as cercariae and adult worms, previously performed by other authors in some other strains. A comparison among authors was made. Besides, we aimed to identify different isoforms of one of the vaccine candidates, the gluthation-S-transferase protein (Sm28GST), by 2D SDS-PAGE and mass spectrometry, and to achieve its immunologic detection using sera from rabbits immunized with synthetic peptides derived from the Sm28GST protein. These techniques allowed the identification of some of the target molecules of the protective immune response that are being evaluated as potential members of a multi-component and multi-stage anti-S. mansoni vaccine and to clarify if the selected peptides induce antibodies that are able to recognize different isoforms of the Sm28GST Es esencial comprender la forma como las larvas de Schistosoma mansoni invaden y los mecanismos de evasión inmune utilizados por larvas y adultos, para el desarrollo racional de vacunas o drogas para prevenir o curar la esquistosomiasis. Este parásito tiene una organización molecular muy compleja en todos sus estadíos, por lo que la identificación de las proteínas más importantes es clave para investigar el metabolismo del esquistosoma y la interacción del parásito con el sistema inmune del hospedero. El objetivo de este trabajo fue evaluar el repertorio proteico del parásito utilizando una aproximación proteómica y la caracterización de extractos proteicos de dos estadios parasitarios diferentes de un aislado venezolano, como la cercaria y el verme adulto, previamente realizado por otros autores en otras aislados. Se realizó una comparación entre autores. Además, se identificaron diferentes isoformas de uno de los candidatos a vacuna, la glutation S transferasa (Sm28GST) por 2D SDS-PAGE y espectrometría de masas y se logró su detección inmunológica, usando sueros de conejos inmunizados con péptidos sintéticos derivados de la proteína Sm28GST. Estas téc
Secretory glands in cercaria of the neuropathogenic schistosome Trichobilharzia regenti - ultrastructural characterization, 3-D modelling, volume and pH estimations
Anna Ligasová, Jana Bulantová, Ond?ej ?ebesta, Martin Ka?ny, Karel Koberna, Libor Mike?
Parasites & Vectors , 2011, DOI: 10.1186/1756-3305-4-162
Abstract: The architecture and 3-D models of two types of acetabular penetration glands, their ducts and of the head gland are shown here. We characterized secretory vesicles in all three gland types by means of TEM and confirmed accuracy of the models obtained by confocal microscopy. The results of two independent approaches showed that the glands occupy ca. one third of cercarial body volume (postacetabular glands ca. 15%, circumacetabular 12% and head gland 6%). The inner environment within the two types of acetabular glands differed significantly as evidenced by dissimilar ability to bind fluorescent markers and by pH value which was higher in circumacetabular (7.44) than in postacetabular (7.08) glands.As far as we know, this is the first presentation of a 3-D model of cercarial glands and the first exact estimation of the volumes of the three gland types in schistosomes. Our comparisons between T. regenti and S. mansoni implied that the architecture and ultrastructure of the glands is most likely conserved within the family. Only minor variations were found between the two species. It seems that the differences in molecular composition have no effect on general appearance of the secretory cells in TEM. Fluorescent markers employed in this study, distinguishing between secretory vesicles and gland types, can be useful in further studies of mechanisms used by cercariae for host invasion. Results of the first attempts to estimate pH within schistosome glands may help further understanding of regulation of enzymatic activities present within the glands.Among several species of trematode cercariae penetrating the skin of vertebrate hosts, schistosomes are of particular interest as the causative agents of human disease (schistosomiasis - syn. Bilharziasis). The morphology and structure of penetration glands has been described in detail in Schistosoma mansoni cercariae. These glands are composed of five pairs of large secretory cells located in the vicinity of the ventral suck
Page 1 /72
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.