The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Gilles Dreyfuss - One of the best experts on this subject based on the ideXlab platform.
-
Fasciola hepatica: development of redial generations in experimental infections of Pseudosuccinea columella
Parasitology research, 2014Co-Authors: Y. Dar, Daniel Rondelaud, Philippe Vignoles, Gilles DreyfussAbstract:Experimental infections of Egyptian Pseudosuccinea columella with one or two miracidia of Fasciola hepatica per snail were carried out to determine the developmental pattern (normal or abnormal) of redial generations and specify the number of free rediae developing in snails according to their generation. Controls were constituted by a French population of Galba truncatula infected according to the same protocol. Most infected P. columella showed a normal development of redial generations (96.2-98.1 vs 75.5-85.7% for G. truncatula). In each redial category, free rediae were more numerous in P. columella than in G. truncatula, and their number were also greater in the two-miracidia groups than in single-Miracidium infections for each lymnaeid considered separately. This increase in redial production was mainly due to the number of first mother (R1a) rediae producing daughter rediae only: 2 per P. columella (vs one redia in G. truncatula) in single-Miracidium groups and 3.1 (vs 1.9) in the two-miracidia groups. In P. columella, the mean total number of free rediae developing in single-Miracidium and bimiracidial infections was 77.2 and 117.6, respectively (instead of 33.5 and 52.1 rediae in G. truncatula). The number of F. hepatica rediae present in P. columella was related to the number of fully grown sporocysts and the quantity of R1a rediae which developed into the snail body.
-
Fasciola hepatica: the infectivity of cattle-origin miracidia had increased over the past years in central France.
Parasitology Research Journal of Parasitology, 2007Co-Authors: Gilles Dreyfuss, Philippe Vignoles, Daniel RondelaudAbstract:A retrospective study on experimental infections of Galba truncatula, originating from four populations, was carried out to determine the infectivity of Fasciola hepatica miracidia in snails either subjected to single-Miracidium or bimiracidial exposures in 2006 and to compare it with results found before 1990 in other experiments using the same protocol. In single-Miracidium infections, the prevalence of snail infection was significantly greater in 2006 than in experiments performed before 1980, while snail survival at day 30 postexposure showed insignificant differences. In bimiracidial infections, snail survival in two snail groups was significantly lower in 2006 than in experiments performed from 1981 to 1990, while insignificant differences were found for the other two populations of G. truncatula. Compared to results found between 1981 and 1990, the prevalence of snail infection did not significantly differ in 2006. In each population considered alone, the mean number of cercariae shed by infected snails did not significantly vary, whatever the date of experiment and the number of miracidia used for each exposure. The greater infectivity of F. hepatica miracidia towards snails might be the consequence of specific molecules such as triclabendazole used since 1990 to treat fasciolosis in cattle from central France.
-
Oviposition of Lymnaea truncatula infected by Fasciola hepatica under experimental conditions.
Parasitology research, 1999Co-Authors: Gilles Dreyfuss, Daniel Rondelaud, C. Vareille-morelAbstract:Experimental infections of Lymnaea truncatula by Fasciola hepatica (one, two, or three miracidia per snail) were carried out under laboratory conditions to analyze the oviposition of infected snails and determine the characteristics of their egg masses. In the infected snails from the three groups, egg-laying steadily decreased until week 4 postexposure and stopped afterward until the end of the experiment, except for the cercaria-shedding snails from the one-Miracidium group, for which low numbers of egg masses were noted between weeks 9 and 12. In uninfected snails the number of egg masses decreased until week 4 and remained low during subsequent weeks. At weeks 11 and 12 postexposure the natality rate was 98.9% in controls, 56% in the cercaria-shedding snails from the one-Miracidium group, and 59.2-68.5% in uninfected snails. In the cercaria-shedding snails from the one-Miracidium group the restoration of reproduction activity after week 8 may be explained by a lower parasite burden in these snails than in those from the two- and three-Miracidium groups.
-
Paramphistomum daubneyi : the development of redial generations in the snail Lymnaea truncatula
Parasitology research, 1996Co-Authors: M. Abrous, Daniel Rondelaud, Gilles DreyfussAbstract:Rediae of Paramphistomum daubneyi were counted and measured in Lymnaea truncatula to elucidate the variability in the numbers of free rediae and cercariae occurring between naturally infected snails and experimental single-Miracidium infections. Experiments were performed using one Miracidium per snail and snail raising was carried out at 20°C. Two redial generations succeeded each other in the snail until day 49. A mean of 8–10 rediae differentiated in the sporocyst at days 7 and 14; the remaining germ balls and redial embryos decreased in number after day 21. First-generation rediae became free in the snail’s body starting at day 14 and their number increased to a mean of 7.5 at day 49, with a maximum of 10 rediae being detected in 1 snail. They produced second-generation rediae, which exited from the body starting at day 28, and then cercariae, which exited from day 42 onward. The count of second-generation rediae was 6–6.2/snail at day 49, with a maximum of 12 being detected in 1 snail; they produced only cercariae.
-
Paramphistomum daubneyi and Fasciola hepatica: the effect of dual infection on prevalence and cercarial shedding in preadult Lymnaea glabra.
The Journal of parasitology, 1996Co-Authors: M. Abrous, Daniel Rondelaud, Gilles DreyfussAbstract:Preadult Lymnaea glabra measuring 4-6 mm in height were each exposed to 1 Paramphistomum daubneyi Miracidium before being exposed to 1 Miracidium of Fasciola hepatica. Total prevalence of infection in the snail groups from 3 different populations ranged from 33% to 39%. In each group, snails harboring larval forms of P. daubneyi, F. hepatica, or both, were noted. If the results from the 3 snail populations are pooled, the total prevalence of snail infection was 13.6% in snails harboring only F. hepatica larvae, 13% in those harboring only P. daubneyi larvae, and 10% in those with both trematodes. Cercarial shedding was obtained from snails harboring F. hepatica larval forms; in the case of snails infected with both trematodes, the mean number of metacercariae ranged from 13 to 21 for F. hepatica, and from 8 to 14 for P. daubneyi. No infected snails were found in snail groups exposed only to 1 trematode miracidia.
V. R. Southgate - One of the best experts on this subject based on the ideXlab platform.
-
The in vitro transformation of the Miracidium to the mother sporocyst of Schistosoma margrebowiei; changes in the parasite surface and implications for interactions with snail plasma factors.
Parasitology, 1992Co-Authors: B. E. Daniel, T. M. Preston, V. R. SouthgateAbstract:SUMMARYThe in vitro transformation of the Miracidium to the mother sporocyst of Schistosoma margrebowiei was initiated by placing the Miracidium in mammalian physiological saline. The transformation occurs in stages: the cilia cease beating; the ciliated plates become detached from the intercellular ridges and underlying muscle layers; the intercellular ridges spread over the body surface eventually forming a new tegument; the sporocyst changes from an ovoid to a tubular shape in about 48 h at room temperature. The surfaces of the Miracidium, sporocyst and cercaria of S. margrebowiei display stage-specific carbohydrates on their surfaces as indicated by lectin staining. Ricin120 stains the cilia alone of the Miracidium whereas peanut agglutinin stains the larval surface except for the cilia. The intercellular ridges of the Miracidium stain with concanavalin A and wheat germ agglutinin, and these lectins stain the entire surface of the mature mother sporocyst. The cercaria is the only larval stage which stains positively with asparagus pea lectin. Bulinus nasutus is incompatible with Schistosoma margrebowiei; the haemolymph of this snail contains an agglutinin which agglutinates a wide variety of mammalian erythrocytes including those of human ABO blood groups. The haemagglutinin titre of B. nasutus plasma is reduced after incubation with miracidia of S. margrebowiei indicating that the agglutinin is absorbed onto the surface of this larval stage but not that of the mother sporocyst or cercaria. The possible roles of agglutinins in host–parasite interactions together with the significance of the differences in the surface carbohydrates of the larval stages are discussed.
Daniel Rondelaud - One of the best experts on this subject based on the ideXlab platform.
-
Fasciola hepatica: development of redial generations in experimental infections of Pseudosuccinea columella
Parasitology research, 2014Co-Authors: Y. Dar, Daniel Rondelaud, Philippe Vignoles, Gilles DreyfussAbstract:Experimental infections of Egyptian Pseudosuccinea columella with one or two miracidia of Fasciola hepatica per snail were carried out to determine the developmental pattern (normal or abnormal) of redial generations and specify the number of free rediae developing in snails according to their generation. Controls were constituted by a French population of Galba truncatula infected according to the same protocol. Most infected P. columella showed a normal development of redial generations (96.2-98.1 vs 75.5-85.7% for G. truncatula). In each redial category, free rediae were more numerous in P. columella than in G. truncatula, and their number were also greater in the two-miracidia groups than in single-Miracidium infections for each lymnaeid considered separately. This increase in redial production was mainly due to the number of first mother (R1a) rediae producing daughter rediae only: 2 per P. columella (vs one redia in G. truncatula) in single-Miracidium groups and 3.1 (vs 1.9) in the two-miracidia groups. In P. columella, the mean total number of free rediae developing in single-Miracidium and bimiracidial infections was 77.2 and 117.6, respectively (instead of 33.5 and 52.1 rediae in G. truncatula). The number of F. hepatica rediae present in P. columella was related to the number of fully grown sporocysts and the quantity of R1a rediae which developed into the snail body.
-
Fasciola hepatica: the infectivity of cattle-origin miracidia had increased over the past years in central France.
Parasitology Research Journal of Parasitology, 2007Co-Authors: Gilles Dreyfuss, Philippe Vignoles, Daniel RondelaudAbstract:A retrospective study on experimental infections of Galba truncatula, originating from four populations, was carried out to determine the infectivity of Fasciola hepatica miracidia in snails either subjected to single-Miracidium or bimiracidial exposures in 2006 and to compare it with results found before 1990 in other experiments using the same protocol. In single-Miracidium infections, the prevalence of snail infection was significantly greater in 2006 than in experiments performed before 1980, while snail survival at day 30 postexposure showed insignificant differences. In bimiracidial infections, snail survival in two snail groups was significantly lower in 2006 than in experiments performed from 1981 to 1990, while insignificant differences were found for the other two populations of G. truncatula. Compared to results found between 1981 and 1990, the prevalence of snail infection did not significantly differ in 2006. In each population considered alone, the mean number of cercariae shed by infected snails did not significantly vary, whatever the date of experiment and the number of miracidia used for each exposure. The greater infectivity of F. hepatica miracidia towards snails might be the consequence of specific molecules such as triclabendazole used since 1990 to treat fasciolosis in cattle from central France.
-
Oviposition of Lymnaea truncatula infected by Fasciola hepatica under experimental conditions.
Parasitology research, 1999Co-Authors: Gilles Dreyfuss, Daniel Rondelaud, C. Vareille-morelAbstract:Experimental infections of Lymnaea truncatula by Fasciola hepatica (one, two, or three miracidia per snail) were carried out under laboratory conditions to analyze the oviposition of infected snails and determine the characteristics of their egg masses. In the infected snails from the three groups, egg-laying steadily decreased until week 4 postexposure and stopped afterward until the end of the experiment, except for the cercaria-shedding snails from the one-Miracidium group, for which low numbers of egg masses were noted between weeks 9 and 12. In uninfected snails the number of egg masses decreased until week 4 and remained low during subsequent weeks. At weeks 11 and 12 postexposure the natality rate was 98.9% in controls, 56% in the cercaria-shedding snails from the one-Miracidium group, and 59.2-68.5% in uninfected snails. In the cercaria-shedding snails from the one-Miracidium group the restoration of reproduction activity after week 8 may be explained by a lower parasite burden in these snails than in those from the two- and three-Miracidium groups.
-
Fasciola hepatica: Characteristics of Infection inLymnaea truncatulain Relation to the Number of Miracidia at Exposure
Experimental parasitology, 1999Co-Authors: G Dreyfuss, Daniel Rondelaud, P. Vignoles, C. Vareille-morelAbstract:Experimental infections of Lymnaea truncatula by Fasciola hepatica were carried out in three snail populations to determine whether the number of miracidia used for each snail at exposure (1, 2, 5, 10, or 20 per snail) had any influence on the characteristics of Fasciola infection and metacercarial production. The number of miracidia had a significant influence on snail survival at day 30 postexposure and the frequency of infected L. truncatula that died without shedding (NCS snails). The frequency of NCS snails, the growth of cercaria-shedding snails throughout the experiment, the time between exposure and the first cercarial shedding, the duration of shedding, and the number of metacercariae were independent of the number of miracidia used for each snail. The highest metacercaria productivity for each Miracidium was found in single-Miracidium infections. Single-Miracidium infections were the most effective, as the mean number of cercariae was the same as in other groups, whereas their survival rate was much higher.
-
Paramphistomum daubneyi : the development of redial generations in the snail Lymnaea truncatula
Parasitology research, 1996Co-Authors: M. Abrous, Daniel Rondelaud, Gilles DreyfussAbstract:Rediae of Paramphistomum daubneyi were counted and measured in Lymnaea truncatula to elucidate the variability in the numbers of free rediae and cercariae occurring between naturally infected snails and experimental single-Miracidium infections. Experiments were performed using one Miracidium per snail and snail raising was carried out at 20°C. Two redial generations succeeded each other in the snail until day 49. A mean of 8–10 rediae differentiated in the sporocyst at days 7 and 14; the remaining germ balls and redial embryos decreased in number after day 21. First-generation rediae became free in the snail’s body starting at day 14 and their number increased to a mean of 7.5 at day 49, with a maximum of 10 rediae being detected in 1 snail. They produced second-generation rediae, which exited from the body starting at day 28, and then cercariae, which exited from day 42 onward. The count of second-generation rediae was 6–6.2/snail at day 49, with a maximum of 12 being detected in 1 snail; they produced only cercariae.
V Radev - One of the best experts on this subject based on the ideXlab platform.
-
argentophilic structures of the Miracidium of echinochasmus perfoliatus trematoda echinosmatidae
Parasite, 1998Co-Authors: Vassil Dimitrov, I Kanev, V Bezprozvanich, V RadevAbstract:Les auteurs decrivent les structures argyrophiles du Miracidium d'Echinochosmus perfoliotus. les poissons contenant les metacercaires a l'origine de la souche ont ete recoltes dans les environs de Vladivostok (Russie extreme orientales. les Miracidiums impregnes dans une solution de AgNO 3 a 0,5 %, portent 21 cellules ciliees disposees sur quatre rangees: 6 + 9 + 4 + 2. Sur le terebratorium on observe jusqu'a 23 structures identiques a des papilles, alignees selon trois axes et formant quatre groupes. Une papille est situee a la base de chaque cellule dorsale et ventrale de la premiere rangee et deux papilles a la base de chaque cellule laterale de cette meme rangee. les ocelles sont situes au-dessous de la premiere rangee de cellules ciliees. les deux pores excreteurs sont places au-dessus des cellules ciliees de la derniere rangee. Les resultats obtenus sont compares a ceux connus chez les autres especes du genre.
-
Argentophilic structures of the Miracidium of Echinochasmus perfoliatus (Trematoda: Echinosmatidae)
Parasite (Paris France), 1998Co-Authors: Vassil Dimitrov, I Kanev, V Bezprozvanich, V RadevAbstract:Argentophilic structures of the Miracidium of Echinochasmus perfoliatus were described from material collected in the vicinity of Vladivostok, Far East of Russia. Impregnated with 0.5% solution of AgNO3 Miracidium showed 21 epidermal plates arranged in four rows: 6 + 9 + 4 + 2. Up to 23 papilla-like structures on the terebratorium were arranged along three axes and in four groups. A single papilla was located at the base of each of ventral and dorsal epidermal plates of the first row. Two papillae were located at the base of each of lateral epidermal plates of the first row. The eyespots were located posterior to the first row of plates. Two excretory pores were located anterior to the last row of plates. The results obtained were compared with the argentophilic structures of closely related species of the genus Echinochasmus.
-
Argentophilic Structures of the Miracidium of Echinostoma trivolvis (Cort, 1914) (Trematoda: Echinostomatidae)
The Journal of parasitology, 1995Co-Authors: Vassil Dimitrov, Ivan Kanev, Bernard Fried, V RadevAbstract:Argentophilic structures of the Miracidium of Echinostoma trivolvis were described from 80 specimens reared from material originally collected in eastern Pennsylvania, U.S.A. Miracidia were impregnated with 0.5% aqueous silver nitrate solution. The Miracidium has 18 epidermal plates arranged in 4 rows of 6 + 6 + 4 + 2 = 18. Up to 20 papillalike structures on the terebratorium were arranged along 3 axes and in 5 groups. A single papilla was located at the base of each of the 6 epidermal plates of the first row. The eyespots were located posterior to the first row of plates and 2 excretory pores were located anterior to the last row of plates.
R. Alan Wilson - One of the best experts on this subject based on the ideXlab platform.
-
The proteasome-ubiquitin pathway in the Schistosoma mansoni egg has development- and morphology-specific characteristics
Molecular and biochemical parasitology, 2010Co-Authors: William Mathieson, William Castro-borges, R. Alan WilsonAbstract:Schistosoma mansoni eggs, consisting of an ovum surrounded by nutritive vitelline cells packaged in a tanned protein shell, are produced by paired worms residing in the mesenteric veins of the human host. The vitelline cells are degraded as the larval Miracidium matures, the fully developed egg either crossing the gut wall to escape the host or becoming lodged in the host's tissues where it dies and disintegrates, inducing a potentially pathological immune response. Thus, the egg is central to both the transmission of the parasite and the aetiology of the disease. Here we present the first study investigating protein turnover in the egg. We establish that the ubiquitin-proteasome pathway (UPP) changes with egg development and furthermore, that the morphological components of the fully developed egg (the Miracidium and the subshell envelope) also exhibit different proteasome subunit expression profiles. We conclude that the UPP is responsible not only for degrading the vitelline cells but is also more highly developed in the envelope than in the Miracidium. The envelope is involved in the defence of the Miracidium and produces the proteins that the egg secretes, presumably to facilitate its escape from the host, so the UPP probably has a multi-faceted role in the egg's biology.
-
A comparative proteomic study of the undeveloped and developed Schistosoma mansoni egg and its contents: The Miracidium, hatch fluid and secretions
International journal for parasitology, 2009Co-Authors: William Mathieson, R. Alan WilsonAbstract:The schistosome egg is the key agent responsible both for transmission of the parasite from human to molluscan host, and is the primary cause of pathogenesis in schistosomiasis. Characterisation of its proteome is a crucial step in understanding the egg's interactions with the mammalian host. We devised a scheme to isolate undeveloped eggs from mature schistosome eggs by Percoll gradient and then fractionate the mature egg into miracidial, hatch fluid and secreted protein preparations. The soluble proteins contained within the five preparations were separated by two-dimensional electrophoresis and their spot patterns compared by image analysis. Large numbers of representative spots were then excised and subjected to tandem mass spectrometry to obtain identities. In this way, the principal components of each sub-proteome were established. Chaperones were the most abundant category, with heat shock protein 70 (HSP70) dominant in the undeveloped egg and Schistosoma mansoni protein 40 (Smp-40) in the Miracidium. Cytoskeletal proteins were expressed at similar levels in the undeveloped egg and Miracidium, with tubulins the most abundant. The proteins of energy metabolism reflected the change from anaerobic to aerobic metabolism as the Miracidium developed. None of the above categories was abundant in the hatch fluid but this peri-miracidial compartment was highly enriched for defence proteins such as thioredoxin. Hatch fluid also contained several host proteins and schistosome proteins of unknown function, highlighting its distinct nature and potentially its role. The egg secretions could not be compared with the other preparations due to their unique composition featuring the previously characterised IL-4-inducing principal of S. mansoni eggs (IPSE), Omega-1, egg secreted protein 15 (ESP15), a micro-exon gene 2 (MEG-2) protein and two members of the recently described MEG-3 family. This last preparation contains the subset of egg proteins that probably enables eggs to escape from host tissues and may also initiate granuloma formation, emphasising the need to establish fully the roles of its components in schistosome biology.
