The Experts below are selected from a list of 4938 Experts worldwide ranked by ideXlab platform
Wilfried Haas - One of the best experts on this subject based on the ideXlab platform.
-
Snail odour-clouds: spreading and contribution to the transmission success of Trichobilharzia ocellata (Trematoda, Digenea) Miracidia
Oecologia, 2005Co-Authors: J Hertel, Martin Kalbe, Bernhard Haberl, Alexander Holweg, Wilfried HaasAbstract:Chemical communication among freshwater organisms is an adaptation to improve their coexistence. Here,we focus on the chemical cues secreted by the freshwater gastropod Lymnaea stagnalis, which are known to stimulate behavioural responses of Trichobilharzia ocellata (Plathelminthes, Digenea, Trematoda) Miracidia. Such responses are commonly claimed to influence transmission positively, but in response to chemical cues Miracidia randomly change their swimming direction. This kind of response does not necessarily increase transmission, because Miracidia may be trapped at the periphery of very large snail odour-clouds, which may prevent them from approaching the snail. On the other hand, the odour clouds may be too small to improve host-localisation. To shed light on these scenarios, the spreading of molecules released around L. stagnalis (active space) was visualised by recording host-finding responses of T. ocellata Miracidia when they approached snails. Behavioural responses of Miracidia indicated the spreading of compounds forming an attractive active space only around the host-snail L. stagnalis, but not around sympatric non-host-snail species. The active space increased approximately linearly with the time the snail rested at the same spot and within 5 min it reached a volume of more than 30 times that of the snail. We also demonstrated in a large-scale experiment, that the active space of L. stagnalis significantly increases the transmission success of T. ocellata Miracidia. Additionally, the microhabitat selection of T. ocellata Miracidia was studied, demonstrating that peripheral locations near the water surface were preferred, which are also preferred sites of L. stagnalis. Improved chemoperception and microhabitat selection may have been a consequence of coevolution with snails and benefited Miracidia, which became efficient transmissive stages.
-
heredity of specific host finding behaviour in schistosoma mansoni Miracidia
Parasitology, 2004Co-Authors: Martin Kalbe, Bernhard Haberl, J Hertel, Wilfried HaasAbstract:Two strains of Schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of Miracidia to snail-conditioned water. An Egyptian strain of S. mansoni , capable of distinguishing its host snail Biomphalaria alexandrina from other snails was cycled repeatedly through Biomphalaria glabrata , the intermediate host of a Brazilian strain known to respond even to non-susceptible snails with high intensity. After 5 cycles in the non-natural host, Miracidia of the Egyptian strain still retained their preference for the original host snail. In a second experiment, host-finding behaviour of hybrids between these two parasite strains was studied. In the F 1 generation, hybrids of both parental combinations showed the same low degree of specificity as the pure-bred Brazilian strain. Approximately one quarter of F 2 hybrids proved to be as discriminatory as the Egyptian strain, confirming dominant Mendelian inheritance of non-specificity in schistosome Miracidial host-finding behaviour. Moreover, hybrids seem to have lost the ability to develop in B. alexandrina , possibly suggesting a link between host recognition and host compatibility. The heredity of this behavioural trait is of evolutionary and epidemiological significance, since a shift to low host-finding specificity might have been a prerequisite for S. mansoni to acquire new host snails after being introduced to South America by the slave trade.
-
Schistosoma mansoni Miracidial host-finding: Species specificity of an Egyptian strain
Parasitology Research, 1996Co-Authors: Martin Kalbe, Bernhard Haberl, Wilfried HaasAbstract:The effect of snail-conditioned water (SCW) from Biomphalaria alexandrina , a pigmented and an albino strain of B. glabrata , and Lymnaea stagnalis on the host-finding behavior of Miracidia of two Brazilian and one Egyptian strain of Schistosoma mansoni was studied. Miracidia of the Egyptian strain significantly preferred their suitable host B. alexandrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. However, Miracidia of both Brazilian strains did not differentiate between SCW from three of the snail species; only the pigmented B. glabrata elicited weaker responses. The releasing cues of SCW for Miracidial host-finding phases are macromolecular glycoconjugates. An analysis of SCW by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotting, and subsequent carbohydrate detection showed that the band patterns of glycoconjugates differed significantly among the four snail strains. Therefore, differing chemical characteristics of the signaling glycoconjugates could be the basis for the observed host specificity in Miracidial host-finding.
-
Snail-host-finding by Miracidia and Cercariae: Chemical Host Cues
Parasitology Today, 1995Co-Authors: Wilfried Haas, B. Haberl, M. Kalbe, M. KörnerAbstract:Snails act as intermediate hosts in trematode life cycles, and many studies have dealt with the question of how Miracidia, mainly of schistosomes, find and recognize their snail hosts. However, the published results on the chemical snail host cues that attract Miracidia of Schistosoma mansoni have been contradictory. Here, Wilfried Haas, Bernhard Haberl, Martin Kalbe and Martina Korner review data that indicate that macromolecular glycoproteins are the attractants, and that schistosome Miracidia can distinguish between snail strains during their chemo-orientation towards the hosts. in echinostome life cycles gastropods also act as second intermediate hosts and are actively invaded by cercariae. However, these cercariae approach their snail hosts with types of chemo-orientation that differ from those of Miracidia, and they respond to small molecular host cues
Bernhard Haberl - One of the best experts on this subject based on the ideXlab platform.
-
Snail odour-clouds: spreading and contribution to the transmission success of Trichobilharzia ocellata (Trematoda, Digenea) Miracidia
Oecologia, 2005Co-Authors: J Hertel, Martin Kalbe, Bernhard Haberl, Alexander Holweg, Wilfried HaasAbstract:Chemical communication among freshwater organisms is an adaptation to improve their coexistence. Here,we focus on the chemical cues secreted by the freshwater gastropod Lymnaea stagnalis, which are known to stimulate behavioural responses of Trichobilharzia ocellata (Plathelminthes, Digenea, Trematoda) Miracidia. Such responses are commonly claimed to influence transmission positively, but in response to chemical cues Miracidia randomly change their swimming direction. This kind of response does not necessarily increase transmission, because Miracidia may be trapped at the periphery of very large snail odour-clouds, which may prevent them from approaching the snail. On the other hand, the odour clouds may be too small to improve host-localisation. To shed light on these scenarios, the spreading of molecules released around L. stagnalis (active space) was visualised by recording host-finding responses of T. ocellata Miracidia when they approached snails. Behavioural responses of Miracidia indicated the spreading of compounds forming an attractive active space only around the host-snail L. stagnalis, but not around sympatric non-host-snail species. The active space increased approximately linearly with the time the snail rested at the same spot and within 5 min it reached a volume of more than 30 times that of the snail. We also demonstrated in a large-scale experiment, that the active space of L. stagnalis significantly increases the transmission success of T. ocellata Miracidia. Additionally, the microhabitat selection of T. ocellata Miracidia was studied, demonstrating that peripheral locations near the water surface were preferred, which are also preferred sites of L. stagnalis. Improved chemoperception and microhabitat selection may have been a consequence of coevolution with snails and benefited Miracidia, which became efficient transmissive stages.
-
heredity of specific host finding behaviour in schistosoma mansoni Miracidia
Parasitology, 2004Co-Authors: Martin Kalbe, Bernhard Haberl, J Hertel, Wilfried HaasAbstract:Two strains of Schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of Miracidia to snail-conditioned water. An Egyptian strain of S. mansoni , capable of distinguishing its host snail Biomphalaria alexandrina from other snails was cycled repeatedly through Biomphalaria glabrata , the intermediate host of a Brazilian strain known to respond even to non-susceptible snails with high intensity. After 5 cycles in the non-natural host, Miracidia of the Egyptian strain still retained their preference for the original host snail. In a second experiment, host-finding behaviour of hybrids between these two parasite strains was studied. In the F 1 generation, hybrids of both parental combinations showed the same low degree of specificity as the pure-bred Brazilian strain. Approximately one quarter of F 2 hybrids proved to be as discriminatory as the Egyptian strain, confirming dominant Mendelian inheritance of non-specificity in schistosome Miracidial host-finding behaviour. Moreover, hybrids seem to have lost the ability to develop in B. alexandrina , possibly suggesting a link between host recognition and host compatibility. The heredity of this behavioural trait is of evolutionary and epidemiological significance, since a shift to low host-finding specificity might have been a prerequisite for S. mansoni to acquire new host snails after being introduced to South America by the slave trade.
-
Interactions related to non-host snails in the host-finding process of Euparyphium albuferensis and Echinostoma friedi (Trematoda: Echinostomatidae) Miracidia
Parasitology Research, 2003Co-Authors: Carla Muñoz-antoli, Rafael Toledo, María Trelis, Bernhard Haberl, Mónica Gozalbo, José-guillermo EstebanAbstract:In order to determine whether the Miracidia of Euparyphium albuferensis and Echinostoma friedi are sensitive to their host snail (HS) and capable of discriminating between HS and non-host snails (NHS), or whether these NHS can interfere and thus reduce the infection rates (decoy effect), a total of three experiments were conducted with HS, NHS and snail-conditioned water (SCW). Gyraulus chinensis is the HS for E. albuferensis Miracidia, while Physa acuta , Radix peregra and Lymnaea fuscus are considered NHS. For E. friedi Miracidia R. peregra , G. chinensis and L. fuscus are the HS, while P. acuta is the NHS. The NHS R . peregra produces the greatest decoy effect on Euparyphium albuferensis Miracidia, while R. peregra , as the HS of Echinostoma friedi Miracidia, is always subject to a NHS decoy effect. However, an increase in E. friedi Miracidia infectivity is observed in its HS G. chinensis , in the presence of SCW of P. acuta . These experimental results might explain the low prevalence of snails infected with E. albuferensis Miracidia in their natural habitat.
-
Schistosoma mansoni Miracidial host-finding: Species specificity of an Egyptian strain
Parasitology Research, 1996Co-Authors: Martin Kalbe, Bernhard Haberl, Wilfried HaasAbstract:The effect of snail-conditioned water (SCW) from Biomphalaria alexandrina , a pigmented and an albino strain of B. glabrata , and Lymnaea stagnalis on the host-finding behavior of Miracidia of two Brazilian and one Egyptian strain of Schistosoma mansoni was studied. Miracidia of the Egyptian strain significantly preferred their suitable host B. alexandrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. However, Miracidia of both Brazilian strains did not differentiate between SCW from three of the snail species; only the pigmented B. glabrata elicited weaker responses. The releasing cues of SCW for Miracidial host-finding phases are macromolecular glycoconjugates. An analysis of SCW by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotting, and subsequent carbohydrate detection showed that the band patterns of glycoconjugates differed significantly among the four snail strains. Therefore, differing chemical characteristics of the signaling glycoconjugates could be the basis for the observed host specificity in Miracidial host-finding.
Martin Kalbe - One of the best experts on this subject based on the ideXlab platform.
-
Snail odour-clouds: spreading and contribution to the transmission success of Trichobilharzia ocellata (Trematoda, Digenea) Miracidia
Oecologia, 2005Co-Authors: J Hertel, Martin Kalbe, Bernhard Haberl, Alexander Holweg, Wilfried HaasAbstract:Chemical communication among freshwater organisms is an adaptation to improve their coexistence. Here,we focus on the chemical cues secreted by the freshwater gastropod Lymnaea stagnalis, which are known to stimulate behavioural responses of Trichobilharzia ocellata (Plathelminthes, Digenea, Trematoda) Miracidia. Such responses are commonly claimed to influence transmission positively, but in response to chemical cues Miracidia randomly change their swimming direction. This kind of response does not necessarily increase transmission, because Miracidia may be trapped at the periphery of very large snail odour-clouds, which may prevent them from approaching the snail. On the other hand, the odour clouds may be too small to improve host-localisation. To shed light on these scenarios, the spreading of molecules released around L. stagnalis (active space) was visualised by recording host-finding responses of T. ocellata Miracidia when they approached snails. Behavioural responses of Miracidia indicated the spreading of compounds forming an attractive active space only around the host-snail L. stagnalis, but not around sympatric non-host-snail species. The active space increased approximately linearly with the time the snail rested at the same spot and within 5 min it reached a volume of more than 30 times that of the snail. We also demonstrated in a large-scale experiment, that the active space of L. stagnalis significantly increases the transmission success of T. ocellata Miracidia. Additionally, the microhabitat selection of T. ocellata Miracidia was studied, demonstrating that peripheral locations near the water surface were preferred, which are also preferred sites of L. stagnalis. Improved chemoperception and microhabitat selection may have been a consequence of coevolution with snails and benefited Miracidia, which became efficient transmissive stages.
-
heredity of specific host finding behaviour in schistosoma mansoni Miracidia
Parasitology, 2004Co-Authors: Martin Kalbe, Bernhard Haberl, J Hertel, Wilfried HaasAbstract:Two strains of Schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of Miracidia to snail-conditioned water. An Egyptian strain of S. mansoni , capable of distinguishing its host snail Biomphalaria alexandrina from other snails was cycled repeatedly through Biomphalaria glabrata , the intermediate host of a Brazilian strain known to respond even to non-susceptible snails with high intensity. After 5 cycles in the non-natural host, Miracidia of the Egyptian strain still retained their preference for the original host snail. In a second experiment, host-finding behaviour of hybrids between these two parasite strains was studied. In the F 1 generation, hybrids of both parental combinations showed the same low degree of specificity as the pure-bred Brazilian strain. Approximately one quarter of F 2 hybrids proved to be as discriminatory as the Egyptian strain, confirming dominant Mendelian inheritance of non-specificity in schistosome Miracidial host-finding behaviour. Moreover, hybrids seem to have lost the ability to develop in B. alexandrina , possibly suggesting a link between host recognition and host compatibility. The heredity of this behavioural trait is of evolutionary and epidemiological significance, since a shift to low host-finding specificity might have been a prerequisite for S. mansoni to acquire new host snails after being introduced to South America by the slave trade.
-
Schistosoma mansoni Miracidial host-finding: Species specificity of an Egyptian strain
Parasitology Research, 1996Co-Authors: Martin Kalbe, Bernhard Haberl, Wilfried HaasAbstract:The effect of snail-conditioned water (SCW) from Biomphalaria alexandrina , a pigmented and an albino strain of B. glabrata , and Lymnaea stagnalis on the host-finding behavior of Miracidia of two Brazilian and one Egyptian strain of Schistosoma mansoni was studied. Miracidia of the Egyptian strain significantly preferred their suitable host B. alexandrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. However, Miracidia of both Brazilian strains did not differentiate between SCW from three of the snail species; only the pigmented B. glabrata elicited weaker responses. The releasing cues of SCW for Miracidial host-finding phases are macromolecular glycoconjugates. An analysis of SCW by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotting, and subsequent carbohydrate detection showed that the band patterns of glycoconjugates differed significantly among the four snail strains. Therefore, differing chemical characteristics of the signaling glycoconjugates could be the basis for the observed host specificity in Miracidial host-finding.
J Hertel - One of the best experts on this subject based on the ideXlab platform.
-
Snail odour-clouds: spreading and contribution to the transmission success of Trichobilharzia ocellata (Trematoda, Digenea) Miracidia
Oecologia, 2005Co-Authors: J Hertel, Martin Kalbe, Bernhard Haberl, Alexander Holweg, Wilfried HaasAbstract:Chemical communication among freshwater organisms is an adaptation to improve their coexistence. Here,we focus on the chemical cues secreted by the freshwater gastropod Lymnaea stagnalis, which are known to stimulate behavioural responses of Trichobilharzia ocellata (Plathelminthes, Digenea, Trematoda) Miracidia. Such responses are commonly claimed to influence transmission positively, but in response to chemical cues Miracidia randomly change their swimming direction. This kind of response does not necessarily increase transmission, because Miracidia may be trapped at the periphery of very large snail odour-clouds, which may prevent them from approaching the snail. On the other hand, the odour clouds may be too small to improve host-localisation. To shed light on these scenarios, the spreading of molecules released around L. stagnalis (active space) was visualised by recording host-finding responses of T. ocellata Miracidia when they approached snails. Behavioural responses of Miracidia indicated the spreading of compounds forming an attractive active space only around the host-snail L. stagnalis, but not around sympatric non-host-snail species. The active space increased approximately linearly with the time the snail rested at the same spot and within 5 min it reached a volume of more than 30 times that of the snail. We also demonstrated in a large-scale experiment, that the active space of L. stagnalis significantly increases the transmission success of T. ocellata Miracidia. Additionally, the microhabitat selection of T. ocellata Miracidia was studied, demonstrating that peripheral locations near the water surface were preferred, which are also preferred sites of L. stagnalis. Improved chemoperception and microhabitat selection may have been a consequence of coevolution with snails and benefited Miracidia, which became efficient transmissive stages.
-
heredity of specific host finding behaviour in schistosoma mansoni Miracidia
Parasitology, 2004Co-Authors: Martin Kalbe, Bernhard Haberl, J Hertel, Wilfried HaasAbstract:Two strains of Schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of Miracidia to snail-conditioned water. An Egyptian strain of S. mansoni , capable of distinguishing its host snail Biomphalaria alexandrina from other snails was cycled repeatedly through Biomphalaria glabrata , the intermediate host of a Brazilian strain known to respond even to non-susceptible snails with high intensity. After 5 cycles in the non-natural host, Miracidia of the Egyptian strain still retained their preference for the original host snail. In a second experiment, host-finding behaviour of hybrids between these two parasite strains was studied. In the F 1 generation, hybrids of both parental combinations showed the same low degree of specificity as the pure-bred Brazilian strain. Approximately one quarter of F 2 hybrids proved to be as discriminatory as the Egyptian strain, confirming dominant Mendelian inheritance of non-specificity in schistosome Miracidial host-finding behaviour. Moreover, hybrids seem to have lost the ability to develop in B. alexandrina , possibly suggesting a link between host recognition and host compatibility. The heredity of this behavioural trait is of evolutionary and epidemiological significance, since a shift to low host-finding specificity might have been a prerequisite for S. mansoni to acquire new host snails after being introduced to South America by the slave trade.
Taede Sminia - One of the best experts on this subject based on the ideXlab platform.
-
Analysis of surface carbohydrates of Trichobilharzia ocellata Miracidia and sporocysts using lectin binding techniques.
Parasitology, 1991Co-Authors: M J Gerhardus, J M Baggen, Wil P.w. Van Der Knaap, Taede SminiaAbstract:Miracidia and in vitro-derived primary sporocysts of the avian schistosome Trichobilharzia ocellata were studied for the expression and the characteristics of glycoconjugate moieties comprising the surface coat. Using a panel of 9 peroxidase labelled lectins, several different lectin binding sites were demonstrated on the larvae. Fixed Miracidia have binding sites for 7 of the lectins; wheat-germ agglutinin binds to both the ciliated plates and the tegumental ridges between them; the other 6 lectins bind to the plates only. Three of the Miracidia-binding lectins, wheat-germ agglutinin, concanavalin A and peanut agglutinin, also bind to fixed sporocysts. Since the Miracidial ridges are devoid of binding sites for concanavalin A and peanut agglutinin, whereas the sporocyst tegument binds these lectins, it appears that these sites become exposed during or shortly after transformation. In saturation experiments, low concentrations of peanut agglutinin and concanavalin A are bound more avidly by sporocysts than by Miracidia, indicating a higher binding affinity of the former. The two larval forms do not differ in affinity for wheat-germ agglutinin but they have different binding capacities; when offered in high concentrations, more of this lectin is bound by sporocysts than by Miracidia. Lectin binding was competitively inhibited by adding the appropriate free saccharides. Live larvae showed the same lectin binding pattern as did fixed specimens. Proteinase treatment reduced lectin binding to living and, to a lesser extent, to fixed larvae, suggesting that binding sites are constituents of proteoglycoconjugates. After SDS-PAGE of extracts from Miracidia and sporocysts and subsequent Western blotting, some of the lectins failed to bind glycoproteins, others reacted with an array of bands. The patterns differed among the lectins and each lectin gave different patterns for Miracidia and sporocysts. The results obtained with these two lectin-binding techniques support the conclusion that stage-specific proteoglycoconjugates occur at the surface of T. ocellata larvae.