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Javier Dieguezuribeondo - One of the best experts on this subject based on the ideXlab platform.
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Saprolegnia milanezii sp nov a new species of Saprolegniales oomycota straminipila from brazil
Phytotaxa, 2016Co-Authors: Sarah Cristina Oliveira Rocha, Jose Vladimir Sandovalsierra, Danilo Reis Goncalves, Javier Dieguezuribeondo, Agostina V. Marano, Ana Lucia De Jesus, Gustavo Henrique Jeronimo, Carmen Lidia Amorim PireszottarelliAbstract:Saprolegnia milanezii sp. nov . is described as a new species of the genus Saprolegnia (Saprolegniales, Oomycota). It has been collected from freshwater samples at “Parque Estadual da Ilha do Cardoso”, Cananeia, Sao Paulo State, Brazil. This species is characterized by rare antheridia, extended stalk near the oogonial septum and subcentric oospores. Phylogenetic analysis using concatenated ITS and LSU rDNA regions confirmed the position of this new species into the genus Saprolegnia as sister group of S. furcata .
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a comprehensive protocol for improving the description of Saprolegniales oomycota two practical examples Saprolegnia aenigmatica sp nov and Saprolegnia racemosa sp nov
PLOS ONE, 2015Co-Authors: Jose Vladimir Sandovalsierra, Javier DieguezuribeondoAbstract:The description, identification and classification of organisms are the pillar in biodiversity and evolutionary studies. The fungal-like organism Saprolegnia contains important animal pathogens. However, its taxonomy is weak, making it difficult to perform further studies. This problem mainly arises from the unavailability of suitable holotypes. We propose a standardized protocol for describing Saprolegnia spp. that includes good cultural practices and proper holotype preservation. In order to illustrate this new proposal, we describe two species, Saprolegnia aenigmatica sp. nov. and Saprolegnia racemosa sp. nov., based on the recently described molecular operational taxonomic units (MOTUs), phylogenetic relationships, and the analyses of morphological features. We show that they belong to two different MOTUs that are grouped into two sister clades. Morphologically, we find that S. racemosa exhibits a species-specific character, i.e., aggrupation of oogonia in racemes, while S. aenigmatica does not have any specific characters. Analyses of a combined set of characters, i.e., length and breadth of sporangia, length/breadth ratio (l/b) of oogonia, cyst and oospore diameter, and the number of oospores per oogomium, allow distinguishing these two species. To improve Saprolegnia taxonomy, we propose to incorporate into the protologue: (i) several isolates of the new species; (ii) the rDNA sequences to compare them to data-bases of Saprolegnia sequences of reference; (iii) a phylogenetic analysis to check relationships with other species; (iv) to preserve holotypes in absolute ethanol and to include lyophilized material from holotype; and (v) the ex-type as a pure culture from single-spore isolates stored in at least two different collections.
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Saprolegnia species affecting the salmonid aquaculture in chile and their associations with fish developmental stage
Aquaculture, 2014Co-Authors: Jose Vladimir Sandovalsierra, Luis Zaror, María P. Martín, Fadua Latifeugenin, Javier DieguezuribeondoAbstract:article The rapid increase in the aquaculture production of salmonids has been followed by a rise in several diseases. In particular, saprolegniosis can account for at least 10% of the annual economic loss in salmonids. In this study, we investigated the main Saprolegnia species involved in saprolegniosis of salmonids in Chile, and their association with specific developmental stages of the host fish. For this purpose, we studied 244 isolates of Saprolegnia- affected Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and king salmon (Oncorhynchus tshawytscha) from the salmon farming regions, using a recently developed identification strategy based on mo- lecular taxonomical operational units. We found that the Saprolegnia species associated with diseased salmon were Saprolegnia australis, Saprolegnia delica, Saprolegnia diclina, Saprolegnia ferax, Saprolegnia parasitica and two new Saprolegnia species observed during this study. In order to determine whether there were any specific species associations with different stages in the fish life cycle, we applied mosaic plots and correspondence anal- yses for categorical data. These analyses showed a strong association of S. parasitica with samples from the adult stage of the fish (χ 2 = 196.29, p b 0.0001), while the species S. australis, S. diclina and Saprolegnia sp. 2 were
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molecular identification of a bronopol tolerant strain of Saprolegnia australis causing egg and fry mortality in farmed brown trout salmo trutta
Fungal Biology, 2014Co-Authors: Svetlana Rezinciuc, Jose Vladimir Sandovalsierra, Javier DieguezuribeondoAbstract:Some species of the genus Saprolegnia, such as Saprolegnia diclina and Saprolegnia ferax are responsible for devastating infections on salmonid eggs. Members of this group cause Saprolegniasis, a disease resulting in considerable economic losses in aquaculture. Although both S. diclina and S. ferax have received much attention, the role of other Saprolegnia species in infecting fish eggs is less known. For this purpose, we have investigated the aetiology of chronic egg mortality events occurring in farmed brown trout, Salmo trutta. A total of 48 isolates were obtained from eggs with signs of infection as well as from water samples. A molecular analysis based on nrDNA internal transcribed spacer (ITS) operational taxonomic units indicated that the majority of the isolates correspond to Saprolegnia australis. All isolates of S. australis exhibited the same random amplified polymorphic DNA (RAPD) band patterns suggesting that a single strain is implicated in egg infections. The isolates followed Koch postulates using trout eggs and fry. Under standard concentrations of bronopol commonly used in farms, these isolates could grow, but not sporulate. However, both growth and sporulation were recovered when treatment was removed. This study shows that S. australis can infect and kill salmon eggs, and helps in defining oomycetes core pathogens.
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differences in susceptibility to Saprolegnia infections among embryonic stages of two anuran species
Oecologia, 2011Co-Authors: Maria Jose Fernandezbeneitez, Manuel E Ortizsantaliestra, Miguel Lizana, Javier DieguezuribeondoAbstract:Many amphibians are known to suffer embryonic die-offs as a consequence of Saprolegnia infections; however, little is known about the action mechanisms of Saprolegnia and the host–pathogen relationships. In this study, we have isolated and characterized the species of Saprolegnia responsible for infections of embryos of natterjack toad (Bufo calamita) and Western spadefoot toad (Pelobates cultripes) in mountainous areas of Central Spain. We also assessed the influence of the developmental stage within the embryonic period on the susceptibility to the Saprolegnia species identified. Only one strain of Saprolegnia was isolated from B. calamita and identified as S. diclina. For P. cultripes, both S. diclina and S. ferax were identified. Healthy embryos of both amphibian species suffered increased mortality rates when exposed to the Saprolegnia strains isolated from individuals of the same population. Embryonic developmental stage was crucial in determining the sensitivity of embryos to Saprolegnia infection. The mortalities of P. cultripes and B. calamita embryos exposed at Gosner stages 15 (rotation) and 19 (heart beating) were almost total 72 h after challenge with Saprolegnia, while those exposed at stage 12 (late gastrula) showed no significant effects at that time. This is the first study to demonstrate the role of embryonic development on the sensitivity of amphibians to Saprolegnia.
Ida Skaar - One of the best experts on this subject based on the ideXlab platform.
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efficacy and safety of boric acid as a preventive treatment against Saprolegnia infection in nile tilapia oreochromis niloticus
Scientific Reports, 2019Co-Authors: Shimaa E Ali, Ida Skaar, Oystein Evensen, Amr Ahmed Abdelrahim Gamil, Harrison CharokarisaAbstract:Saprolegniosis is a worldwide fungal-like infection affecting freshwater fishes and their eggs. Reports show high mortalities and subsequent economic losses annually from Saprolegnia infections. Most therapeutants against Saprolegnia spp. infections are inefficient and some have negative impact on the environment. In this study, we have investigated the ability of boric acid (BA) to prevent Saprolegnia infection in Nile tilapia (Oreochromis niloticus). BA inhibited radial growth of Saprolegnia hyphae in vitro. Complete in vitro growth inhibition was found at a concentration of ≥0.6 g/L. Inhibitory effects were also observed in vivo when Nile tilapia were experimentally challenged with Saprolegnia spores and followed over 10 days post challenge and under continuous exposure to different BA concentrations. No signs of saprolegniosis were observed in fish treated with BA at concentrations of 0.4 g/L and above. Comet assay revealed that BA has low toxicity in tilapia continuously exposed to concentrations of 0.2–0.6 g/L for 96 h. Additionally, no significant histomorphological changes were observed in BA-treated fish compared to non-treated controls. Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) enzyme levels indicated reduction in systemic tissue damage associated with Saprolegnia infection. This study demonstrates the potential of BA as a prophylactic measure against Saprolegnia infection in tilapia, and we recommend additional studies on environmental impact.
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a thicker chorion gives ova of atlantic salmon salmo salar l the upper hand against Saprolegnia infections
Journal of Fish Diseases, 2016Co-Authors: M M Songe, Mohammad Nasif Sarowar, Ida Skaar, Oystein Evensen, Ariane Willems, K Rajan, Keith Drynan, P Van WestAbstract:Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.
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Saprolegnia diclina iiia and s parasitica employ different infection strategies when colonizing eggs of atlantic salmon salmo salar l
Journal of Fish Diseases, 2016Co-Authors: M M Songe, Even Thoen, Oystein Evensen, Ariane Willems, J Wiiknielsen, P Van West, Ida SkaarAbstract:Here, we address the morphological changes of eyed eggs of Atlantic salmon, Salmo salar L. infected with Saprolegnia from a commercial hatchery and after experimental infection. Eyed eggs infected with Saprolegnia spp. from 10 Atlantic salmon females were obtained. Egg pathology was investigated by light and scanning electron microscopy. Eggs from six of ten females were infected with S. parasitica, and two females had infections with S. diclina clade IIIA; two Saprolegnia isolates remained unidentified. Light microscopy showed S. diclina infection resulted in the chorion in some areas being completely destroyed, whereas eggs infected with S. parasitica had an apparently intact chorion with hyphae growing within or beneath the chorion. The same contrasting pathology was found in experimentally infected eggs. Scanning electron microscopy revealed that S. parasitica grew on the egg surface and hyphae were found penetrating the chorion of the egg, and re-emerging on the surface away from the infection site. The two Saprolegnia species employ different infection strategies when colonizing salmon eggs. Saprolegnia diclina infection results in chorion destruction, while S. parasitica penetrates intact chorion. We discuss the possibility these infection mechanisms representing a necrotrophic (S. diclina) vs. a facultative biotrophic strategy (S. parasitica).
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diversity of aquatic pseudomonas species and their activity against the fish pathogenic oomycete Saprolegnia
PLOS ONE, 2015Co-Authors: Yiying Liu, Even Thoen, Ida Skaar, Vincent Bulone, Jos M. Raaijmakers, Elzbieta Rzeszutek, Menno Van Der Voort, Pieter C Dorrestein, Irene De BruijnAbstract:Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture.
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Phenotypic and genotypic analysis of Pseudomonas isolates.
2015Co-Authors: Yiying Liu, Even Thoen, Ida Skaar, Vincent Bulone, Jos M. Raaijmakers, Elzbieta Rzeszutek, Menno Van Der Voort, Pieter C Dorrestein, Irene De BruijnAbstract:The isolates were obtained from healthy salmon egg samples and salmon eggs infected with Saprolegnia. (A) Mean percentage of the number of bacterial isolates that were inhibitory to hyphal growth of Saprolegnia diclina VS20 and Saprolegnia parasitica CBS 223.65, tested by observation of an inhibition halo around the bacterial colony (right panel insert). (B) Mean percentage of the number of bacterial isolates that produce biosurfactants based on the drop collapse assay (right panel insert). Error bars represent the S.E.M. (N = 6). The asterisk indicates a statistically significant difference (P
Pieter Van West - One of the best experts on this subject based on the ideXlab platform.
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List of selected secreted proteins of Saprolegnia parasitica with their description and expression levels in different life stages.
2018Co-Authors: Svetlana Rezinciuc, Jose Vladimir Sandoval-sierra, Yolanda Ruiz-león, Pieter Van West, Javier Diéguez-uribeondoAbstract:List of selected secreted proteins of Saprolegnia parasitica with their description and expression levels in different life stages.
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reprint of Saprolegnia strains isolated from river insects and amphipods are broad spectrum pathogens
Fungal Biology, 2014Co-Authors: Mohammad Nasif Sarowar, Albert Hendrik Van Den Berg, Debbie Mclaggan, Mark R Young, Pieter Van WestAbstract:Saprolegnia species are destructive pathogens to many aquatic organisms and are found in most parts of the world. Reports based on phylogenetic analysis suggest that Saprolegnia strains isolated from aquatic animals such as crustaceans and frogs are close to Saprolegnia strains isolated from infected fish or fish eggs and vice versa. However, it has often been assumed that host specificity occurs for each individual isolate or strain. Here we demonstrate that Saprolegnia spp. can have multiple hosts and are thus capable of infecting different aquatic organisms. Saprolegnia delica, Saprolegnia hypogyna, and 2 strains of Saprolegnia diclina were isolated from aquatic insects and amphipods while S. delica, Saprolegnia ferax, Pythium pachycaule, and a Pythium sp. were isolated from the water of a medium to fast flowing river. The ITS region of the rRNA gene was sequenced for all isolates. In challenge experiments, all four isolates from insects were found to be highly pathogenic to eggs of Atlantic salmon (Salmo salar) and embryos of the African clawed frog (Xenopus laevis). We found that Saprolegnia spp. isolated from salmon eggs were also able to successfully establish infection in nymphs of stonefly (Perla bipunctata) and embryos of X. laevis). These results suggest that Saprolegnia spp. are capable of infecting multiple hosts, which may give them an advantage during seasonal variation in their natural environments.
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Saprolegnia strains isolated from river insects and amphipods are broad spectrum pathogens
Fungal Biology, 2013Co-Authors: Mohammad Nasif Sarowar, Albert Hendrik Van Den Berg, Debbie Mclaggan, Mark R Young, Pieter Van WestAbstract:Saprolegnia species are destructive pathogens to many aquatic organisms and are found in most parts of the world. Reports based on phylogenetic analysis suggest that Saprolegnia strains isolated from aquatic animals such as crustaceans and frogs are close to Saprolegnia strains isolated from infected fish or fish eggs and vice versa. However, it has often been assumed that host specificity occurs for each individual isolate or strain. Here we demonstrate that Saprolegnia spp. can have multiple hosts and are thus capable of infecting different aquatic organisms. Saprolegnia delica, Saprolegnia hypogyna, and 2 strains of Saprolegnia diclina were isolated from aquatic insects and amphipods while S. delica, Saprolegnia ferax, Pythium pachycaule, and a Pythium sp. were isolated from the water of a medium to fast flowing river. The ITS region of the rRNA gene was sequenced for all isolates. In challenge experiments, all four isolates from insects were found to be highly pathogenic to eggs of Atlantic salmon (Salmo salar) and embryos of the African clawed frog (Xenopus laevis). We found that Saprolegnia spp. isolated from salmon eggs were also able to successfully establish infection in nymphs of stonefly (Perla bipunctata) and embryos of X. laevis). These results suggest that Saprolegnia spp. are capable of infecting multiple hosts, which may give them an advantage during seasonal variation in their natural environments.
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The impact of the water moulds Saprolegnia diclina and Saprolegnia parasitica on natural ecosystems and the aquaculture industry
Fungal Biology Reviews, 2013Co-Authors: Albert Hendrik Van Den Berg, Javier Diéguez-uribeondo, Debbie Mclaggan, Pieter Van WestAbstract:Abstract A very large number of diseases in agriculture and aquaculture are caused by fungal-like micro-organisms, classified as Oomycetes or water moulds. Collectively, oomycetes represent a huge threat to global food security. In addition, several oomycetes can cause environmental disasters, by wiping out native species of trees, crustacians and amphibians. The group representing the aquatic oomycetes are relatively understudied in contrast to their terrestrial counterparts that predominantly infect plants (e.g. Phytophthora, Pythium and Bremia spp.). This review focuses on the unique characteristics of two aquatic Oomycetes, Saprolegnia parasitica and Saprolegnia diclina with respect to their impact on aquaculture, animal health and the surrounding environment. The species characteristics, ecology, biology, infectivity and identification methods are described and the latest research insights are discussed.
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Expressed sequence tags from the oomycete fish pathogen Saprolegnia parasitica reveal putative virulence factors
BMC microbiology, 2005Co-Authors: Trudy Torto-alalibo, Miaoying Tian, Kamal Gajendran, Mark E. Waugh, Pieter Van WestAbstract:Background The oomycete Saprolegnia parasitica is one of the most economically important fish pathogens. There is a dramatic recrudescence of Saprolegnia infections in aquaculture since the use of the toxic organic dye malachite green was banned in 2002. Little is known about the molecular mechanisms underlying pathogenicity in S. parasitica and other animal pathogenic oomycetes. In this study we used a genomics approach to gain a first insight into the transcriptome of S. parasitica.
Mohammad Nasif Sarowar - One of the best experts on this subject based on the ideXlab platform.
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Saprolegnia molecular phylogeny among farmed teleosts in nova scotia canada
Journal of Fish Diseases, 2019Co-Authors: Mohammad Nasif Sarowar, Roland Cusack, James DustonAbstract:To identify the pathogens causing saprolegniosis among farmed fish in Nova Scotia, 172 infected tissues and 23 water samples were collected from six species of teleosts: Atlantic salmon (Salmo salar), brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus), brook trout (Salvelinus fontinalis), striped bass (Morone saxatilis) and rainbow trout (Oncorhynchus mykiss) at nine facilities over a 600 km range. Following laboratory culture, 132 isolates were recovered. Six species of oomycetes were identified from analysis of the internal transcribed spacer (ITS) sequence of the nrDNA: Saprolegnia parasitica, Saprolegnia ferax, Saprolegnia diclina, Saprolegnia aenigmatica, Saprolegnia torulosa, Saprolegnia sp. and Pythiopsis cymosa. Further phylogenetic analyses of the ITS and cytochrome c oxidase subunit 1 (Cox1) regions revealed four strains of Saprolegnia parasitica (named here as S1, S2, S3 and S4), of which S1 and S2 were common (37% and 42% of the isolates), and two strains of S. ferax. Among S. parasitica, S2 and S3 are more closely related to each other than to S1 based on the phylogenetic analyses and predicted RNA secondary structure of the ITS region. Sexual structures with a similar morphology were formed by S1 and S3 in vitro, but were not formed by S2.
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Molecular identification of oomycete species affecting aquaculture in Bangladesh
KeAi, 2019Co-Authors: Mohammad Nasif Sarowar, Tahmina Nasrin, Tania Naznin, Zakir Hossain, Md Jakir Hossain, Mohammad Matiur RahmanAbstract:Fish mycotic disease outbreaks occur due to infections with oomycete pathogens such as Saprolegnia spp. and Aphanomyces invadans, and cause large-scale fish production losses. Despite its negative impact on aquaculture, little is known about the diversity of oomycete pathogens. The aim of this study was to identify the diversity of pathogenic oomycetes causing infections in major aquaculture zones of Mymensingh and Jessore regions in Bangladesh. A total of 449 water and infected fish samples were collected from 28 fish farms in both regions of which 29 samples were able to grow out with mycelia on the Potato Dextrose Agar (PDA)/Glucose Peptone Yeast Agar (GPYA) plates. Sequence database searches using the rRNA Internal Transcribed Spacer (ITS) region revealed that 15 belonged to Pythium spp., 12 were Aphanomyces invadans and two corresponded to Saprolegnia parasitica. Five isolates of Pythium spp. were identified to the species level: one was closely related to Pythium catenulatum, four to Pythium rhizo-oryzae, rest were identified up to genus. The Pythium spp. were only isolated from water samples whereas A. invadans and S. parasitica were found in fish lesions. Phylogenetic analysis revealed that a single A. invadans clone exists in the sampled area. The results obtained confirm the existence of pathogenic oomycetes in Bangladesh fish farms and this will pave future research on diversity, prevention and control measures. Keywords: Oomycete, Saprolegnia, Aphanomyces invadans, Internal transcribed spacer (ITS), Phylogen
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a thicker chorion gives ova of atlantic salmon salmo salar l the upper hand against Saprolegnia infections
Journal of Fish Diseases, 2016Co-Authors: M M Songe, Mohammad Nasif Sarowar, Ida Skaar, Oystein Evensen, Ariane Willems, K Rajan, Keith Drynan, P Van WestAbstract:Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.
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reprint of Saprolegnia strains isolated from river insects and amphipods are broad spectrum pathogens
Fungal Biology, 2014Co-Authors: Mohammad Nasif Sarowar, Albert Hendrik Van Den Berg, Debbie Mclaggan, Mark R Young, Pieter Van WestAbstract:Saprolegnia species are destructive pathogens to many aquatic organisms and are found in most parts of the world. Reports based on phylogenetic analysis suggest that Saprolegnia strains isolated from aquatic animals such as crustaceans and frogs are close to Saprolegnia strains isolated from infected fish or fish eggs and vice versa. However, it has often been assumed that host specificity occurs for each individual isolate or strain. Here we demonstrate that Saprolegnia spp. can have multiple hosts and are thus capable of infecting different aquatic organisms. Saprolegnia delica, Saprolegnia hypogyna, and 2 strains of Saprolegnia diclina were isolated from aquatic insects and amphipods while S. delica, Saprolegnia ferax, Pythium pachycaule, and a Pythium sp. were isolated from the water of a medium to fast flowing river. The ITS region of the rRNA gene was sequenced for all isolates. In challenge experiments, all four isolates from insects were found to be highly pathogenic to eggs of Atlantic salmon (Salmo salar) and embryos of the African clawed frog (Xenopus laevis). We found that Saprolegnia spp. isolated from salmon eggs were also able to successfully establish infection in nymphs of stonefly (Perla bipunctata) and embryos of X. laevis). These results suggest that Saprolegnia spp. are capable of infecting multiple hosts, which may give them an advantage during seasonal variation in their natural environments.
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Saprolegnia strains isolated from river insects and amphipods are broad spectrum pathogens
Fungal Biology, 2013Co-Authors: Mohammad Nasif Sarowar, Albert Hendrik Van Den Berg, Debbie Mclaggan, Mark R Young, Pieter Van WestAbstract:Saprolegnia species are destructive pathogens to many aquatic organisms and are found in most parts of the world. Reports based on phylogenetic analysis suggest that Saprolegnia strains isolated from aquatic animals such as crustaceans and frogs are close to Saprolegnia strains isolated from infected fish or fish eggs and vice versa. However, it has often been assumed that host specificity occurs for each individual isolate or strain. Here we demonstrate that Saprolegnia spp. can have multiple hosts and are thus capable of infecting different aquatic organisms. Saprolegnia delica, Saprolegnia hypogyna, and 2 strains of Saprolegnia diclina were isolated from aquatic insects and amphipods while S. delica, Saprolegnia ferax, Pythium pachycaule, and a Pythium sp. were isolated from the water of a medium to fast flowing river. The ITS region of the rRNA gene was sequenced for all isolates. In challenge experiments, all four isolates from insects were found to be highly pathogenic to eggs of Atlantic salmon (Salmo salar) and embryos of the African clawed frog (Xenopus laevis). We found that Saprolegnia spp. isolated from salmon eggs were also able to successfully establish infection in nymphs of stonefly (Perla bipunctata) and embryos of X. laevis). These results suggest that Saprolegnia spp. are capable of infecting multiple hosts, which may give them an advantage during seasonal variation in their natural environments.
Jose Vladimir Sandovalsierra - One of the best experts on this subject based on the ideXlab platform.
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Saprolegnia milanezii sp nov a new species of Saprolegniales oomycota straminipila from brazil
Phytotaxa, 2016Co-Authors: Sarah Cristina Oliveira Rocha, Jose Vladimir Sandovalsierra, Danilo Reis Goncalves, Javier Dieguezuribeondo, Agostina V. Marano, Ana Lucia De Jesus, Gustavo Henrique Jeronimo, Carmen Lidia Amorim PireszottarelliAbstract:Saprolegnia milanezii sp. nov . is described as a new species of the genus Saprolegnia (Saprolegniales, Oomycota). It has been collected from freshwater samples at “Parque Estadual da Ilha do Cardoso”, Cananeia, Sao Paulo State, Brazil. This species is characterized by rare antheridia, extended stalk near the oogonial septum and subcentric oospores. Phylogenetic analysis using concatenated ITS and LSU rDNA regions confirmed the position of this new species into the genus Saprolegnia as sister group of S. furcata .
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a comprehensive protocol for improving the description of Saprolegniales oomycota two practical examples Saprolegnia aenigmatica sp nov and Saprolegnia racemosa sp nov
PLOS ONE, 2015Co-Authors: Jose Vladimir Sandovalsierra, Javier DieguezuribeondoAbstract:The description, identification and classification of organisms are the pillar in biodiversity and evolutionary studies. The fungal-like organism Saprolegnia contains important animal pathogens. However, its taxonomy is weak, making it difficult to perform further studies. This problem mainly arises from the unavailability of suitable holotypes. We propose a standardized protocol for describing Saprolegnia spp. that includes good cultural practices and proper holotype preservation. In order to illustrate this new proposal, we describe two species, Saprolegnia aenigmatica sp. nov. and Saprolegnia racemosa sp. nov., based on the recently described molecular operational taxonomic units (MOTUs), phylogenetic relationships, and the analyses of morphological features. We show that they belong to two different MOTUs that are grouped into two sister clades. Morphologically, we find that S. racemosa exhibits a species-specific character, i.e., aggrupation of oogonia in racemes, while S. aenigmatica does not have any specific characters. Analyses of a combined set of characters, i.e., length and breadth of sporangia, length/breadth ratio (l/b) of oogonia, cyst and oospore diameter, and the number of oospores per oogomium, allow distinguishing these two species. To improve Saprolegnia taxonomy, we propose to incorporate into the protologue: (i) several isolates of the new species; (ii) the rDNA sequences to compare them to data-bases of Saprolegnia sequences of reference; (iii) a phylogenetic analysis to check relationships with other species; (iv) to preserve holotypes in absolute ethanol and to include lyophilized material from holotype; and (v) the ex-type as a pure culture from single-spore isolates stored in at least two different collections.
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Saprolegnia species affecting the salmonid aquaculture in chile and their associations with fish developmental stage
Aquaculture, 2014Co-Authors: Jose Vladimir Sandovalsierra, Luis Zaror, María P. Martín, Fadua Latifeugenin, Javier DieguezuribeondoAbstract:article The rapid increase in the aquaculture production of salmonids has been followed by a rise in several diseases. In particular, saprolegniosis can account for at least 10% of the annual economic loss in salmonids. In this study, we investigated the main Saprolegnia species involved in saprolegniosis of salmonids in Chile, and their association with specific developmental stages of the host fish. For this purpose, we studied 244 isolates of Saprolegnia- affected Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and king salmon (Oncorhynchus tshawytscha) from the salmon farming regions, using a recently developed identification strategy based on mo- lecular taxonomical operational units. We found that the Saprolegnia species associated with diseased salmon were Saprolegnia australis, Saprolegnia delica, Saprolegnia diclina, Saprolegnia ferax, Saprolegnia parasitica and two new Saprolegnia species observed during this study. In order to determine whether there were any specific species associations with different stages in the fish life cycle, we applied mosaic plots and correspondence anal- yses for categorical data. These analyses showed a strong association of S. parasitica with samples from the adult stage of the fish (χ 2 = 196.29, p b 0.0001), while the species S. australis, S. diclina and Saprolegnia sp. 2 were
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molecular identification of a bronopol tolerant strain of Saprolegnia australis causing egg and fry mortality in farmed brown trout salmo trutta
Fungal Biology, 2014Co-Authors: Svetlana Rezinciuc, Jose Vladimir Sandovalsierra, Javier DieguezuribeondoAbstract:Some species of the genus Saprolegnia, such as Saprolegnia diclina and Saprolegnia ferax are responsible for devastating infections on salmonid eggs. Members of this group cause Saprolegniasis, a disease resulting in considerable economic losses in aquaculture. Although both S. diclina and S. ferax have received much attention, the role of other Saprolegnia species in infecting fish eggs is less known. For this purpose, we have investigated the aetiology of chronic egg mortality events occurring in farmed brown trout, Salmo trutta. A total of 48 isolates were obtained from eggs with signs of infection as well as from water samples. A molecular analysis based on nrDNA internal transcribed spacer (ITS) operational taxonomic units indicated that the majority of the isolates correspond to Saprolegnia australis. All isolates of S. australis exhibited the same random amplified polymorphic DNA (RAPD) band patterns suggesting that a single strain is implicated in egg infections. The isolates followed Koch postulates using trout eggs and fry. Under standard concentrations of bronopol commonly used in farms, these isolates could grow, but not sporulate. However, both growth and sporulation were recovered when treatment was removed. This study shows that S. australis can infect and kill salmon eggs, and helps in defining oomycetes core pathogens.
