The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lage Cerenius - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic relationships among plant and animal parasites and saprotrophs in Aphanomyces oomycetes
Fungal Genetics and Biology, 2009Co-Authors: Javier Dieguezuribeondo, E Kozubikova, Carol E Windels, Isabel Ballesteros, Lage Cerenius, Howard Kator, John J. Weiland, M A Garcia, Maria P MartinAbstract:Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.
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lack of specificity of the molecular diagnostic method for identification of Aphanomyces astaci
Bulletin Francais De La Peche Et De La Pisciculture, 2007Co-Authors: Isabel Ballesteros, Lage Cerenius, Maria P Martin, Kenneth Söderhäll, M T Telleria, Javier DieguezuribeondoAbstract:A recent PCR-test developed for identification of Aphanomyces astaci , the organism responsible for crayfish plague, provided false positives for Aphanomyces frigidophilus , Aphanomyces repetans , and some Saprolegnia spp. Real-time PCR showed that with the designed primers, A. astaci and A. frigidophilus cannot be distinguished. The results of this study show that this particular crayfish plague PCR-test ought to be improved and that molecular-based techniques need to be contrasted to histological evidences and disease history.
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physiological and genetic characterisation of some new Aphanomyces strains isolated from freshwater crayfish
Veterinary Microbiology, 2004Co-Authors: Felix Royo, Eakaphun Bangyeekhun, Kenneth Söderhäll, Gunnar Andersson, Jose Luis Muzquiz, Lage CereniusAbstract:Five Aphanomyces strains were isolated during suspected outbreaks of crayfish disease in Spain and Italy. Genetic and physiological evidence show that the strains isolated from the freshwater crayfish Procambarus clarkii and Pacifastacus leniusculus, do not fit into any previously identified group of Aphanomyces astaci and are not capable of killing crayfish following standardised experimental infection. RAPD-PCR and ITS sequencing analysis show a high degree of similarity between the new isolates, while they are clearly different from the A. astaci reference strains. They do, however, possess some properties, which are commonly associated with parasitic species such as repeated zoospore emergence and the lack of sexual reproduction. The five isolates share some physiological properties i.e. a high growth rate, and germination in response to nutrients and, in contrast to A. astaci, they do not express chitinase constitutively during growth or sporulation. Until their taxonomic status is fully elucidated we suggest that the new isolates be given the tentative species name Aphanomyces repetans.
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molecular characterization of the fish pathogenic fungus Aphanomyces invadans
Journal of Fish Diseases, 2003Co-Authors: J H Lilley, Somkiat Kanchanakhan, V Panyawachira, Supranee Chinabut, D Hart, Lage CereniusAbstract:Aphanomyces invadans (Saprolegniaceae) is a peronosporomycete fungus associated with the serious fish disease, epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis. In this study, interspecific relationships were examined between A. invadans isolates and other aquatic animal pathogenic Saprolegniaceae, and saprophytic Saprolegniaceae from EUS-affected areas. Restriction fragment length polymorphisms and sequences of ribosomal DNA confirmed that A. invadans is distinct from all other species studied. A sequence from the internal transcribed spacer region ITS1, unique to A. invadans, was used to design primers for a PCR-based diagnostic test. Intraspecific relationships were also examined by random amplification of polymorphic DNA using 20 isolates of A. invadans from six countries. The isolates showed a high degree of genetic homogeneity using 14 random ten-mer primers. This provides evidence that the fungus has spread across Asia in one relatively rapid episode, which is consistent with reports of outbreaks of EUS. Physiological distinctions between A. invadans and other Aphanomyces species based on a data set of 16 growth parameters showed remarkable taxonomic congruence with the molecular phylogeny.
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host prophenoloxidase expression in freshwater crayfish is linked to increased resistance to the crayfish plague fungus Aphanomyces astaci
Cellular Microbiology, 2003Co-Authors: Lage Cerenius, Eakaphun Bangyeekhun, Pia Keyser, Irene SoderhallAbstract:Host prophenoloxidase expression in freshwater crayfish is linked to increased resistance to the crayfish plague fungus, Aphanomyces astaci.
Harri Kokko - One of the best experts on this subject based on the ideXlab platform.
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the signal crayfish pacifastacus leniusculus in lake tahoe usa hosts multiple Aphanomyces species
Journal of Invertebrate Pathology, 2019Co-Authors: Jenny Makkonen, Harri Kokko, Judson A Ward, John Umek, Raine Kortet, Adam Petrusek, Gokhan Gokmen, Japo JussilaAbstract:Abstract The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lake Tahoe, California, providing 35 axenic cultures of A. astaci as well as two apparently undescribed Aphanomyces spp. isolates. Based on the results of ITS-, chitinase-, mitochondrial rnnS- and rnnL-sequences and microsatellite markers combined, the Lake Tahoe A. astaci isolates were identical to isolates of A. astaci B-haplogroup commonly detected in Europe, and infection experiments confirmed their high virulence towards noble crayfish. One of the two undescribed Aphanomyces spp. isolates was highly similar to an Aphanomyces lineage detected previously in crustacean zooplankton (Daphnia) in Central Europe, while the other was distinct and most closely related (ITS sequence similarity of 93%) to either A. astaci or to Aphanomyces fennicus isolated recently from Astacus astacus in Finland. Neither of the two Aphanomyces spp. isolates caused crayfish mortality under experimental conditions. Our results indicate that the populations of North American signal crayfish can act as carriers of both pathogenic and non-pathogenic Aphanomyces at the same time. Furthermore, considering that a limited number of crayfish individuals from a single location yielded multiple distinct Aphanomyces isolates, our results suggest that substantial species diversity within this genus remains undescribed.
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Mitochondrial genomes and comparative genomics of Aphanomyces astaci and Aphanomyces invadans
Scientific Reports, 2016Co-Authors: Jenny Makkonen, Arto Vesterbacka, Frank Martin, Javier Diéguez-uribeondo, Jari Jussila, Raine Kortet, Harri KokkoAbstract:The genus Aphanomyces (Saprolegniales, Oomycetes) includes species with a variety of ecologies from saprotrophs to plant and animal parasites. Two important species in this genus are A. astaci, the cause of crayfish plague and its close relative, A. invadans , which causes the epizootic ulcerative syndrome on fish. In this study, we have assembled and annotated the mitochondrial (mt) genomes of A. astaci and A. invadans from the whole genome shotgun sequence reads (PRJNA187372; PRJNA258292, respectively). The assembly was generated from A. astaci Pc-genotype strain APO3 and A. invadans strain NJM9701. The sizes of the mtDNAs were 49,489 bp and 49,061 bp for A. astaci and A. invadans, respectively. The species shared similar genetic content and organization encoding 35 proteins, two ribosomal RNAs, three putative open reading frames and 33 transfer RNAs of 19 amino acids for peptide synthesis. Both species also had a large inverted repeat region (LIR) of approximately 12 kb, the LIR contained large and small ribosomal RNAs and eight protein coding genes. These annotated mt genomes serve as a valuable genetic backbone for further development of diagnostic methods and phylogenetic and migration studies of the animal parasitic species of Aphanomyces .
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the signal crayfish is vulnerable to both the as and the psi isolates of the crayfish plague
Knowledge and Management of Aquatic Ecosystems, 2014Co-Authors: Hamdi Aydin, Harri Kokko, Jenny Makkonen, Raine Kortet, H Kukkonen, Japo JussilaAbstract:Key-words: Aphanomyces astaci, susceptible signal crayfish, mortality, stress, molting The carrier status and possible elevated tolerance of the signal crayfish (Pacifastacus leniusculus) against the crayfish plague disease agent (Aphanomyces astaci) has been speculated for several decades. We studied experimentally the responses of the signal crayfish from two Finnish populations against the crayfish plague infection by using two crayfish plague isolates with differing virulences; the highly virulent PsI-isolate and the mid virulent As-isolate. The studied signal crayfish came from two origins: the wild Leppavirta population and the Raukola farmed population of mixed genetic background. Both test groups were infected with A. astaci isolates using the challenge of 10000 spores mL −1 . The isolates were PsIPuujarvi (UEF8866-2) from Lake Puujarvi signal crayfish (year 2003) and As-Kivesjarvi (Evira6462/06) from Lake Kivesjarvi noble crayfish (year 2005 epidemic) in Finland. The crayfish were sampled prior to the experimental challenge with A. astaci to evaluate their A. astaci carrier status. The mortality, molting, feeding activity and other behavior of the crayfish were followed during the experiment. We observedincreasedmortality of the infected groups, related to the molting in some cases, and delayed molting. The impacts of the intense crayfish plague infection on the signal crayfish were clear and the studied populations showed differences in their reactions that are potentially explained by differing physiological conditions and different molt cycle phase. The results show that infection of both tested crayfish plague genotypes affects signal crayfish and is likely one of the main reasons behind losses among signal crayfish populations.
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Latent crayfish plague (Aphanomyces astaci) infection in a robust wild noble crayfish (Astacus astacus) population
Aquaculture, 2011Co-Authors: Japo Jussila, Jenny Makkonen, Raine Kortet, Anssi Vainikka, Harri KokkoAbstract:article i nfo Apparently healthy wild noble crayfish (Astacus astacus) sampled from Lake Mikitanjarvi, Kainuu, Finland in 2009 and 2010 were discovered to be PCR-positive for Aphanomyces astaci. Detection prevalence was lower in 2009 than in 2010. Despite the detected sublethal infection, the Lake Mikitanjarvi population has been pro- ductive and is being under commercial exploitation. Even though it has been suggested frequently that noble crayfish might harbor subclinical crayfish plague infections, this is the first confirmed report, based on molec- ular evidence, of healthy A. astacus carrying A. astaci.
Japo Jussila - One of the best experts on this subject based on the ideXlab platform.
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the signal crayfish pacifastacus leniusculus in lake tahoe usa hosts multiple Aphanomyces species
Journal of Invertebrate Pathology, 2019Co-Authors: Jenny Makkonen, Harri Kokko, Judson A Ward, John Umek, Raine Kortet, Adam Petrusek, Gokhan Gokmen, Japo JussilaAbstract:Abstract The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lake Tahoe, California, providing 35 axenic cultures of A. astaci as well as two apparently undescribed Aphanomyces spp. isolates. Based on the results of ITS-, chitinase-, mitochondrial rnnS- and rnnL-sequences and microsatellite markers combined, the Lake Tahoe A. astaci isolates were identical to isolates of A. astaci B-haplogroup commonly detected in Europe, and infection experiments confirmed their high virulence towards noble crayfish. One of the two undescribed Aphanomyces spp. isolates was highly similar to an Aphanomyces lineage detected previously in crustacean zooplankton (Daphnia) in Central Europe, while the other was distinct and most closely related (ITS sequence similarity of 93%) to either A. astaci or to Aphanomyces fennicus isolated recently from Astacus astacus in Finland. Neither of the two Aphanomyces spp. isolates caused crayfish mortality under experimental conditions. Our results indicate that the populations of North American signal crayfish can act as carriers of both pathogenic and non-pathogenic Aphanomyces at the same time. Furthermore, considering that a limited number of crayfish individuals from a single location yielded multiple distinct Aphanomyces isolates, our results suggest that substantial species diversity within this genus remains undescribed.
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growth survival and spore formation of the pathogenic aquatic oomycete Aphanomyces astaci and fungus fusarium avenaceum are inhibited by zanthoxylum rhoifolium bark extracts in vitro
Fishes, 2018Co-Authors: Caterina Pagliarulo, Japo Jussila, Jenny Makkonen, Daniela Sateriale, Elisa Scioscia, Nunziatina De Tommasi, Roberta Colicchio, Chiara Pagliuca, Elena Scaglione, Paola SalvatoreAbstract:This study aimed to evaluate the in vitro activity of Zanthoxylum rhoifolium bark (Zr-b) extracts against pathogenic aquatic oomycete/fungal isolates that cause different diseases in native European crayfish resulting in an elevated mortality rate and severe economic repercussions. n-hexane, chloroform, chloroform–methanol (9:1) and methanol extracts of Zr-b were used to evaluate the antifungal activity against the strain UEF88662 of Aphanomyces astaci (oomycete) and the strain SMM2 of Fusarium avenaceum (fungus). The anti-oomycete and antifungal activity was quantitatively evaluated by growth, survival and sporulation microbiological assays. The extracts tested demonstrated a dose-dependent inhibitory effect on oomycete and fungal growth and survival, as well as on the production of oomycete and fungal spores. This work presents alternatives for the treatment and prevention of the spreading of Aphanomyces astaci and Fusarium avenaceum, the etiological agents of the diseases crayfish plague and brown spot disease, respectively. The antifungal properties of Zanthoxylum rhoifolium bark extracts warrant further research on their use in the prevention and treatment of both oomycete and fungal diseases. The antifungal properties of Zanthoxylum rhoifolium bark extracts, shown in vitro, indicate the possibility of their use in new therapeutic and prophylactic strategies, providing perspectives for the design of in vivo studies.
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the signal crayfish is vulnerable to both the as and the psi isolates of the crayfish plague
Knowledge and Management of Aquatic Ecosystems, 2014Co-Authors: Hamdi Aydin, Harri Kokko, Jenny Makkonen, Raine Kortet, H Kukkonen, Japo JussilaAbstract:Key-words: Aphanomyces astaci, susceptible signal crayfish, mortality, stress, molting The carrier status and possible elevated tolerance of the signal crayfish (Pacifastacus leniusculus) against the crayfish plague disease agent (Aphanomyces astaci) has been speculated for several decades. We studied experimentally the responses of the signal crayfish from two Finnish populations against the crayfish plague infection by using two crayfish plague isolates with differing virulences; the highly virulent PsI-isolate and the mid virulent As-isolate. The studied signal crayfish came from two origins: the wild Leppavirta population and the Raukola farmed population of mixed genetic background. Both test groups were infected with A. astaci isolates using the challenge of 10000 spores mL −1 . The isolates were PsIPuujarvi (UEF8866-2) from Lake Puujarvi signal crayfish (year 2003) and As-Kivesjarvi (Evira6462/06) from Lake Kivesjarvi noble crayfish (year 2005 epidemic) in Finland. The crayfish were sampled prior to the experimental challenge with A. astaci to evaluate their A. astaci carrier status. The mortality, molting, feeding activity and other behavior of the crayfish were followed during the experiment. We observedincreasedmortality of the infected groups, related to the molting in some cases, and delayed molting. The impacts of the intense crayfish plague infection on the signal crayfish were clear and the studied populations showed differences in their reactions that are potentially explained by differing physiological conditions and different molt cycle phase. The results show that infection of both tested crayfish plague genotypes affects signal crayfish and is likely one of the main reasons behind losses among signal crayfish populations.
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Latent crayfish plague (Aphanomyces astaci) infection in a robust wild noble crayfish (Astacus astacus) population
Aquaculture, 2011Co-Authors: Japo Jussila, Jenny Makkonen, Raine Kortet, Anssi Vainikka, Harri KokkoAbstract:article i nfo Apparently healthy wild noble crayfish (Astacus astacus) sampled from Lake Mikitanjarvi, Kainuu, Finland in 2009 and 2010 were discovered to be PCR-positive for Aphanomyces astaci. Detection prevalence was lower in 2009 than in 2010. Despite the detected sublethal infection, the Lake Mikitanjarvi population has been pro- ductive and is being under commercial exploitation. Even though it has been suggested frequently that noble crayfish might harbor subclinical crayfish plague infections, this is the first confirmed report, based on molec- ular evidence, of healthy A. astacus carrying A. astaci.
Jenny Makkonen - One of the best experts on this subject based on the ideXlab platform.
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the signal crayfish pacifastacus leniusculus in lake tahoe usa hosts multiple Aphanomyces species
Journal of Invertebrate Pathology, 2019Co-Authors: Jenny Makkonen, Harri Kokko, Judson A Ward, John Umek, Raine Kortet, Adam Petrusek, Gokhan Gokmen, Japo JussilaAbstract:Abstract The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lake Tahoe, California, providing 35 axenic cultures of A. astaci as well as two apparently undescribed Aphanomyces spp. isolates. Based on the results of ITS-, chitinase-, mitochondrial rnnS- and rnnL-sequences and microsatellite markers combined, the Lake Tahoe A. astaci isolates were identical to isolates of A. astaci B-haplogroup commonly detected in Europe, and infection experiments confirmed their high virulence towards noble crayfish. One of the two undescribed Aphanomyces spp. isolates was highly similar to an Aphanomyces lineage detected previously in crustacean zooplankton (Daphnia) in Central Europe, while the other was distinct and most closely related (ITS sequence similarity of 93%) to either A. astaci or to Aphanomyces fennicus isolated recently from Astacus astacus in Finland. Neither of the two Aphanomyces spp. isolates caused crayfish mortality under experimental conditions. Our results indicate that the populations of North American signal crayfish can act as carriers of both pathogenic and non-pathogenic Aphanomyces at the same time. Furthermore, considering that a limited number of crayfish individuals from a single location yielded multiple distinct Aphanomyces isolates, our results suggest that substantial species diversity within this genus remains undescribed.
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growth survival and spore formation of the pathogenic aquatic oomycete Aphanomyces astaci and fungus fusarium avenaceum are inhibited by zanthoxylum rhoifolium bark extracts in vitro
Fishes, 2018Co-Authors: Caterina Pagliarulo, Japo Jussila, Jenny Makkonen, Daniela Sateriale, Elisa Scioscia, Nunziatina De Tommasi, Roberta Colicchio, Chiara Pagliuca, Elena Scaglione, Paola SalvatoreAbstract:This study aimed to evaluate the in vitro activity of Zanthoxylum rhoifolium bark (Zr-b) extracts against pathogenic aquatic oomycete/fungal isolates that cause different diseases in native European crayfish resulting in an elevated mortality rate and severe economic repercussions. n-hexane, chloroform, chloroform–methanol (9:1) and methanol extracts of Zr-b were used to evaluate the antifungal activity against the strain UEF88662 of Aphanomyces astaci (oomycete) and the strain SMM2 of Fusarium avenaceum (fungus). The anti-oomycete and antifungal activity was quantitatively evaluated by growth, survival and sporulation microbiological assays. The extracts tested demonstrated a dose-dependent inhibitory effect on oomycete and fungal growth and survival, as well as on the production of oomycete and fungal spores. This work presents alternatives for the treatment and prevention of the spreading of Aphanomyces astaci and Fusarium avenaceum, the etiological agents of the diseases crayfish plague and brown spot disease, respectively. The antifungal properties of Zanthoxylum rhoifolium bark extracts warrant further research on their use in the prevention and treatment of both oomycete and fungal diseases. The antifungal properties of Zanthoxylum rhoifolium bark extracts, shown in vitro, indicate the possibility of their use in new therapeutic and prophylactic strategies, providing perspectives for the design of in vivo studies.
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Mitochondrial genomes and comparative genomics of Aphanomyces astaci and Aphanomyces invadans
Scientific Reports, 2016Co-Authors: Jenny Makkonen, Arto Vesterbacka, Frank Martin, Javier Diéguez-uribeondo, Jari Jussila, Raine Kortet, Harri KokkoAbstract:The genus Aphanomyces (Saprolegniales, Oomycetes) includes species with a variety of ecologies from saprotrophs to plant and animal parasites. Two important species in this genus are A. astaci, the cause of crayfish plague and its close relative, A. invadans , which causes the epizootic ulcerative syndrome on fish. In this study, we have assembled and annotated the mitochondrial (mt) genomes of A. astaci and A. invadans from the whole genome shotgun sequence reads (PRJNA187372; PRJNA258292, respectively). The assembly was generated from A. astaci Pc-genotype strain APO3 and A. invadans strain NJM9701. The sizes of the mtDNAs were 49,489 bp and 49,061 bp for A. astaci and A. invadans, respectively. The species shared similar genetic content and organization encoding 35 proteins, two ribosomal RNAs, three putative open reading frames and 33 transfer RNAs of 19 amino acids for peptide synthesis. Both species also had a large inverted repeat region (LIR) of approximately 12 kb, the LIR contained large and small ribosomal RNAs and eight protein coding genes. These annotated mt genomes serve as a valuable genetic backbone for further development of diagnostic methods and phylogenetic and migration studies of the animal parasitic species of Aphanomyces .
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the signal crayfish is vulnerable to both the as and the psi isolates of the crayfish plague
Knowledge and Management of Aquatic Ecosystems, 2014Co-Authors: Hamdi Aydin, Harri Kokko, Jenny Makkonen, Raine Kortet, H Kukkonen, Japo JussilaAbstract:Key-words: Aphanomyces astaci, susceptible signal crayfish, mortality, stress, molting The carrier status and possible elevated tolerance of the signal crayfish (Pacifastacus leniusculus) against the crayfish plague disease agent (Aphanomyces astaci) has been speculated for several decades. We studied experimentally the responses of the signal crayfish from two Finnish populations against the crayfish plague infection by using two crayfish plague isolates with differing virulences; the highly virulent PsI-isolate and the mid virulent As-isolate. The studied signal crayfish came from two origins: the wild Leppavirta population and the Raukola farmed population of mixed genetic background. Both test groups were infected with A. astaci isolates using the challenge of 10000 spores mL −1 . The isolates were PsIPuujarvi (UEF8866-2) from Lake Puujarvi signal crayfish (year 2003) and As-Kivesjarvi (Evira6462/06) from Lake Kivesjarvi noble crayfish (year 2005 epidemic) in Finland. The crayfish were sampled prior to the experimental challenge with A. astaci to evaluate their A. astaci carrier status. The mortality, molting, feeding activity and other behavior of the crayfish were followed during the experiment. We observedincreasedmortality of the infected groups, related to the molting in some cases, and delayed molting. The impacts of the intense crayfish plague infection on the signal crayfish were clear and the studied populations showed differences in their reactions that are potentially explained by differing physiological conditions and different molt cycle phase. The results show that infection of both tested crayfish plague genotypes affects signal crayfish and is likely one of the main reasons behind losses among signal crayfish populations.
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Latent crayfish plague (Aphanomyces astaci) infection in a robust wild noble crayfish (Astacus astacus) population
Aquaculture, 2011Co-Authors: Japo Jussila, Jenny Makkonen, Raine Kortet, Anssi Vainikka, Harri KokkoAbstract:article i nfo Apparently healthy wild noble crayfish (Astacus astacus) sampled from Lake Mikitanjarvi, Kainuu, Finland in 2009 and 2010 were discovered to be PCR-positive for Aphanomyces astaci. Detection prevalence was lower in 2009 than in 2010. Despite the detected sublethal infection, the Lake Mikitanjarvi population has been pro- ductive and is being under commercial exploitation. Even though it has been suggested frequently that noble crayfish might harbor subclinical crayfish plague infections, this is the first confirmed report, based on molec- ular evidence, of healthy A. astacus carrying A. astaci.
Adam Petrusek - One of the best experts on this subject based on the ideXlab platform.
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the signal crayfish pacifastacus leniusculus in lake tahoe usa hosts multiple Aphanomyces species
Journal of Invertebrate Pathology, 2019Co-Authors: Jenny Makkonen, Harri Kokko, Judson A Ward, John Umek, Raine Kortet, Adam Petrusek, Gokhan Gokmen, Japo JussilaAbstract:Abstract The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lake Tahoe, California, providing 35 axenic cultures of A. astaci as well as two apparently undescribed Aphanomyces spp. isolates. Based on the results of ITS-, chitinase-, mitochondrial rnnS- and rnnL-sequences and microsatellite markers combined, the Lake Tahoe A. astaci isolates were identical to isolates of A. astaci B-haplogroup commonly detected in Europe, and infection experiments confirmed their high virulence towards noble crayfish. One of the two undescribed Aphanomyces spp. isolates was highly similar to an Aphanomyces lineage detected previously in crustacean zooplankton (Daphnia) in Central Europe, while the other was distinct and most closely related (ITS sequence similarity of 93%) to either A. astaci or to Aphanomyces fennicus isolated recently from Astacus astacus in Finland. Neither of the two Aphanomyces spp. isolates caused crayfish mortality under experimental conditions. Our results indicate that the populations of North American signal crayfish can act as carriers of both pathogenic and non-pathogenic Aphanomyces at the same time. Furthermore, considering that a limited number of crayfish individuals from a single location yielded multiple distinct Aphanomyces isolates, our results suggest that substantial species diversity within this genus remains undescribed.
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Aphanomyces astaci presence in japan a threat to the endemic and endangered crayfish species cambaroides japonicus
Aquatic Conservation-marine and Freshwater Ecosystems, 2017Co-Authors: Agata Mrugala, Tadashi Kawai, Eva Kozubikovabalcarova, Adam PetrusekAbstract:Spread of the crayfish plague pathogen, Aphanomyces astaci, by North American crayfish species is considered one of the main reasons for substantial declines and local extinctions of native European crayfish populations. Owing to human introductions, several American crayfish species have become established throughout the world, and thus pose a potential threat to indigenous crayfish populations susceptible to crayfish plague. In Japan, two such widespread alien species, Procambarus clarkii and Pacifastacus leniusculus, were introduced for aquaculture purposes in the late 1920s and since then successfully expanded their ranges. Aggressive interactions with alien crayfish along with habitat modifications have been considered primarily responsible for drastic declines in populations of the Japanese endemic crayfish, Cambaroides japonicus, observed in the last few decades. However, the presence of the crayfish plague pathogen, to which Japanese crayfish are susceptible, may be expected, and could contribute to these declines. Only recently, A. astaci has been reported from Taiwan, and to our knowledge no study focusing on its presence outside of the Western Palearctic has been conducted. To fill this gap, 54 P. clarkii and 47 P. leniusculus individuals from five different Japanese locations were screened using molecular methods recommended by the World Organization for Animal Health. Aphanomyces astaci DNA was detected in all studied populations, altogether in 61% and 21% of examined individuals of P. clarkii and P. leniusculus, respectively. The results provide the first evidence of A. astaci presence in Japan and highlight the threat of pathogen transmission to C. japonicus populations. Copyright © 2016 John Wiley & Sons, Ltd.
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prevalence of the crayfish plague pathogen Aphanomyces astaci in populations of the signal crayfish pacifastacus leniusculus in france evaluating the threat to native crayfish
PLOS ONE, 2013Co-Authors: Lenka Filipova, Klara Matasova, Carine Delaunay, Adam Petrusek, Frederic GrandjeanAbstract:Aphanomyces astaci, the crayfish plague pathogen, first appeared in Europe in the mid-19th century and is still responsible for mass mortalities of native European crayfish. The spread of this parasite across the continent is especially facilitated by invasive North American crayfish species that serve as its reservoir. In France, multiple cases of native crayfish mortalities have been suggested to be connected with the presence of the signal crayfish Pacifastacus leniusculus, which is highly abundant in the country. It shares similar habitats as the native white-clawed crayfish Austropotamobius pallipes and, when infected, the signal crayfish might therefore easily transmit the pathogen to the native species. We investigated the prevalence of A. astaci in French signal crayfish populations to evaluate the danger they represent to local populations of native crayfish. Over 500 individuals of Pacifastacus leniusculus from 45 French populations were analysed, plus several additional individuals of other non-indigenous crayfish species Orconectes limosus, O. immunis and Procambarus clarkii. Altogether, 20% of analysed signal crayfish tested positive for Aphanomyces astaci, and the pathogen was detected in more than half of the studied populations. Local prevalence varied significantly, ranging from 0% up to 80%, but wide confidence intervals suggest that the number of populations infected by A. astaci may be even higher than our results show. Analysis of several individuals of other introduced species revealed infections among two of these, O. immunis and P. clarkii. Our results confirm that the widespread signal crayfish serves as a key reservoir of Aphanomyces astaci in France and therefore represents a serious danger to native crayfish species, especially the white-clawed crayfish. The prevalence in other non-indigenous crayfish should also be investigated as they likely contribute to pathogen transmission in the country.
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re examination of the prevalence of Aphanomyces astaci in north american crayfish populations in central europe by taqman mgb real time pcr
Diseases of Aquatic Organisms, 2011Co-Authors: E Kozubikova, Trude Vrålstad, Lenka Filipova, Adam PetrusekAbstract:We applied quantitative TaqMan minor groove binder real-time polymerase chain reaction (PCR) on DNA isolates from soft abdominal cuticle of 460 North American crayfish Orconectes limosus and Pacifastacus leniusculus, previously tested for Aphanomyces astaci presence by conventional semi-nested PCR. Both approaches target the internal transcribed spacers of the pathogen nuclear ribosomal DNA, but apply different specific sequence motifs and technologies. The real-time PCR approach seems to provide higher sensitivity; the number of crayfish that tested positive increased from 23 to 32%, and 10 additional crayfish populations were indicated as hosting the disease agent. However, the vast majority of newly recorded positives contained very low agent levels, from 5 to 50 PCR-forming units. An isolate producing a false positive result by the semi-nested PCR (apparently undescribed Aphanomyces related to A. astaci) remained negative using the real-time PCR. The present study shows that previous results based on the semi-nested PCR were not substantially influenced by false positives but might have suffered from some false negatives at low agent levels. Combining alternative methods may therefore provide more reliable conclusions on the pathogen's presence. Further, we found positive correlation between the prevalence of infection carriers in American crayfish populations and the average amounts of A. astaci DNA detected in infected local crayfish individuals.
