title: Physiological and genetic characterisation of some new Aphanomyces strains isolated from freshwater crayfish.
abstract: 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.
authors.affiliation: Department of Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden.
authors.forename: Félix
authors.initials: F
authors.lastname: Royo
authors.forename: Gunnar
authors.initials: G
authors.lastname: Andersson
authors.forename: Eakaphun
authors.initials: E
authors.lastname: Bangyeekhun
authors.forename: Jóse Luis
authors.initials: JL
authors.lastname: Múzquiz
authors.forename: Kenneth
authors.initials: K
authors.lastname: Söderhäll
authors.forename: Lage
authors.initials: L
authors.lastname: Cerenius
mesh_terms: D000818:Animals; D044744:Aphanomyces / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D003400:Astacoidea / Q000382:microbiology*; D001483:Base Sequence; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021901:DNA, Intergenic / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary*; D007239:Infections / Q000382:microbiology / Q000662:veterinary*; D007558:Italy / Q000453:epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013030:Spain / Q000453:epidemiology; D013172:Spores, Fungal / Q000254:growth & development; D014871:Water Microbiology
chemical_list: D004271:DNA, Fungal; D021901:DNA, Intergenic; D002686:Chitin; D002688:Chitinases