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| 2. |
- Dieguez-Uribeondo, Javier, et al.
(författare)
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Pathogens, parasites and ectocommensals.
- 2006
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Ingår i: Atlas of crayfish in Europe. - : Publications Scientifiques du Muséum National d'Histoire Naturelle Vol. 64 “Patrimoines Naturels”. - 9782856535790 - 2856535798 ; , s. 135-155
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Bokkapitel (populärvet., debatt m.m.)
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| 3. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes)
- 2009
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 46:5, s. 365-376
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 4. |
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| 5. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Physiological characterization of Saprolegnia parasitica isolates from brown trout
- 1996
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 140:3, s. 247-257
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Tidskriftsartikel (refereegranskat)abstract
- Saprolegnia parasitica has caused large mortalities in brown trout, Salmo trutta, in Spain. Several strains of Saprolegnia parasitica have been isolated from these epizootics and characterized regarding their physiological adaptation and genetic diversity
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| 6. |
- Diéguez-Uribeondo, Javier, et al.
(författare)
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Re-evaluation of the enigmatic species complex Saprolegnia diclina-Saprolegnia parasitica based on morphological, physiological and molecular data
- 2007
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 44:7, s. 585-601
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships among isolates of the Saprolegnia diclina-Saprolegnia parasitica complex were investigated based on ITS rDNA sequences, and correlated with morphological and physiological characters. The isolates studied belong to five phylogenetically separate clades. The majority of presumed parasitic isolates, mostly isolated from fish lesions, fell within a clade that comprises isolates which has been variously named as S. diclina Type 1, S. parasitica, Saprolegnia salmonis or just as unnamed Saprolegnia sp. Presence of bundles of long-hooked hairs on secondary cysts, high frequency of retracted germination, and oogonia production at 7 degrees C (when occurring) were characteristic of this clade. A single isolate identified as S. diclina Type 2 clustered in a clade along with Saprolegnia ferax isolates. The isolates identified as S. diclina s. str. (S. diclina Type 3) distributed in two clades and appeared closely related to Saprolegnia multispora and to a number of Chilean isolates identified as Saprolegnia australis. The ITS sequences of clade I were almost identical even though the isolates were of diverse geographical origins and showed physiological and morphological differences and variations in their pathogenicity. This suggest these species reproduces clonally even in apparently sexually competent isolates. Adaptation to parasitism in Saprolegnia might have occurred at spore level by the development of long-hooked hairs to facilitate host attachment and selection of a retracting germination. The use of the name S. parasitica should be assigned to isolates of clade I that contained isolates forming cysts with bundles of long-hooked hairs.
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| 8. |
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| 9. |
- Jiang, Rays H. Y., et al.
(författare)
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Distinctive Expansion of Potential Virulence Genes in the Genome of the Oomycete Fish Pathogen Saprolegnia parasitica
- 2013
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 9:6, s. e1003272-
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Tidskriftsartikel (refereegranskat)abstract
- Oomycetes in the class Saprolegniomycetidae of the Eukaryotic kingdom Stramenopila have evolved as severe pathogens of amphibians, crustaceans, fish and insects, resulting in major losses in aquaculture and damage to aquatic ecosystems. We have sequenced the 63 Mb genome of the fresh water fish pathogen, Saprolegnia parasitica. Approximately 1/3 of the assembled genome exhibits loss of heterozygosity, indicating an efficient mechanism for revealing new variation. Comparison of S. parasitica with plant pathogenic oomycetes suggests that during evolution the host cellular environment has driven distinct patterns of gene expansion and loss in the genomes of plant and animal pathogens. S. parasitica possesses one of the largest repertoires of proteases (270) among eukaryotes that are deployed in waves at different points during infection as determined from RNA-Seq data. In contrast, despite being capable of living saprotrophically, parasitism has led to loss of inorganic nitrogen and sulfur assimilation pathways, strikingly similar to losses in obligate plant pathogenic oomycetes and fungi. The large gene families that are hallmarks of plant pathogenic oomycetes such as Phytophthora appear to be lacking in S. parasitica, including those encoding RXLR effectors, Crinkler's, and Necrosis Inducing-Like Proteins (NLP). S. parasitica also has a very large kinome of 543 kinases, 10% of which is induced upon infection. Moreover, S. parasitica encodes several genes typical of animals or animal-pathogens and lacking from other oomycetes, including disintegrins and galactose-binding lectins, whose expression and evolutionary origins implicate horizontal gene transfer in the evolution of animal pathogenesis in S. parasitica.
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| 10. |
- Korkut, Gül Gizem, 1986-
(författare)
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Interaction between crayfish and some microorganisms; Effect of temperature
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Innate immunity, which constitutes the first line of defense in vertebrates, is the only immune system that invertebrates rely on to protect themselves from pathogens. The invertebrate immune system is composed of cellular and humoral components. Cellular immunity is phagocytosis, opsonization and encapsulation. The humoral part is mainly composed of the events taking place upon secretion of granules and the enzymes within that lead to the lysis of the pathogen by antimicrobial peptides (AMPs) and the melanization cascade. The Prophenoloxidase (proPO) activating system is an important pathway that is stored in the granules of semigranular and granular hemocytes (blood cells). These cells will degranulate and release the proPO system when activated upon pathogen recognition. This cascade results in the melanization reaction and to trap and eliminate pathogens. White spot syndrome virus (WSSV) is a deadly pathogen mainly targeting crustaceans and causing huge economic losses since its first emergence in 1992 in Taiwan. It is known that WSSV disables the immune system of the host by interfering with the proPO cascade. Temperature is a restricting factor for the WSSV infections however it is not known if its affects are on host immunity or on the virus itself.With the aim of elucidating WSSV infection, we studied the virus entry mechanisms. By crosslinking WSSV with the hemocytes we showed that a new clip-domain serine protease (PlcSP) plays an important role during the WSSV infection in crayfish by means of interacting with WSSV envelope protein VP28. Moreover, we have shown that the viral entry is inhibited at cold temperatures due to temperature’s inhibitory effect on PlcSP expression. We also showed that by slowing down of the host’s metabolism hence proliferation in host tissue either by low temperature or cell cycle inhibitors, we could inhibit WSSV replication once it has entered the host cell. We tested if the temperature effects host or pathogen, or both, we investigated the mortalities, phagocytosis, bacterial clearance, total hemocyte counts, degranulation and melanization rate of crayfish under a cold and warm temperature by using two strains of gram-negative bacteria and LPS. It is apparent that the cellular immunity is more effective at low temperature while the humoral immunity can become overactivated and toxic for the host at higher temperature. Furthermore, we aimed to study the cleavage specificity for PlcSP since it is predicted to be secreted from hemocytes and takes part in the serine protease cascade during melanization reaction.
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