Esterase Isoenzyme Variation in the Genus Saprolegnia, with Particular Reference to the Fish-pathogenic S. diclina-parasitica Complex

Beakes, Gordon W.; Ford, Henry

doi:10.1099/00221287-129-8-2605

Cited by 22 publications

(32 citation statements)

References 22 publications

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“…In this study, the zoospores of tested and reference isolates, which exhibited repeated zoospore emergence (including Spt), were allowed to swim for 150 min in each generation, and they could produce 4 zoospore generations. Hence, our study indicates that the relationship between the length of swimming time and maximal number of zoospore generations in Saprolegnia isolates is similar, although the isolates are genetically different (Table 1).Variations of oogonium morphology (Willoughby 1978), esterase enzyme profiles (Beakes & Ford 1983) and cyst ornamentation (Grandes et al 2000) have been used to distinguish subgroups of Saprolegnia parasitica. In this study, a relationship between zoospore behavior and host-specificity was observed.…”

mentioning

confidence: 72%

Prevalence of a single fish-pathogenic Saprolegnia sp. clone in Finland and Sweden

Bangyeekhun¹,

Pylkkö²,

Vennerström³

et al. 2003

Dis. Aquat. Org.

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Thirty-one isolates of Saprolegnia sp., most originating from infected salmon or trout, were characterised genetically and physiologically. The majority (6 of 31) of the isolates from several widely separated geographical locations was found to be genetically almost identical as assessed by RAPD-PCR. The remaining isolates belonged to 3 different groups with 1 to 3 representatives each. It is suggested that the first group of isolates represents a virulent form of the organism that has been widely spread by clonal propagation. The ability to repeated zoospore emergence, as an alternative to direct germination, seems to characterise specific Saprolegnia genotypes that may have adapted to certain hosts.KEY WORDS: Saprolegnia · Saprolegniosis · Fish disease · Random amplification of polymorphic DNA RAPD · Repeated zoospore emergence Resale or republication not permitted without written consent of the publisherDis Aquat Org 53: [47][48][49][50][51][52][53] 2003 guished the fish lesion isolates from the water isolates, and Beakes (1983) was able to identify S. parasitica from S. diclina. Variation in esterase isoenzyme patterns (Beakes & Ford 1983) and differences in radial growth rate (Willoughby & Copland 1984, Hatai et al. 1990) have been used for determining distinct groups of fish lesion isolates. Restriction fragment length polymorphisms (RFLPs) are useful for classification of Saprolegnia and could distinguish S. parasitica from S. diclina (Molina et al. 1995). Also, random amplification of polymorphic DNA polymerase chain reaction (RAPD-PCR;Welsh & McClelland 1990, Williams et al. 1990) has been applied for analysis of the fish pathogenic Saprolegnia genome (Diéguez-Uribeondo et al. 1996, Bangyeekhun et al. 2001). This latter method provides a sensitive and rapid assay for the assessment of genetic distance between different isolates.In the present study, we applied the RAPD-PCR technique and the presence or absence of repeated zoospore emergence to characterise Saprolegnia sp. isolates obtained from Finland and Sweden to investigate the epidemiology of the saprolegniosis in this region. We found that the majority of the isolates belonged to a single genetically defined group that probably has been widely spread by clonal propagation. MATERIALS AND METHODSSaprolegnia strains. Thirty-one isolates of Saprolegnia spp. were isolated from infected tissue of the brown trout Salmo trutta m. lacustris, trout S. trutta, whitefish Coregonus lavaretus, rainbow trout Oncorhynchus mykiss, brook trout Salvelinus fontinalis, landlocked salmon Salmo salar m. sebago, salmon S. salar, noble crayfish Astacus astacus, and pond water from 6 different locations in Finland and 1 location in Sweden. The isolates from Finland are designated FinX, where X is the isolation number and the isolates from Sweden are designated Swe203 and Swe239 (see Table 1). The following reference isolates were used for comparison: S. parasitica (Spt) isolated from freshwater crayfish Astacus leptodactylus (Söderhäll et al. 1991), S. parasit...

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mentioning

confidence: 72%

Prevalence of a single fish-pathogenic Saprolegnia sp. clone in Finland and Sweden

Bangyeekhun¹,

Pylkkö²,

Vennerström³

et al. 2003

Dis. Aquat. Org.

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“…Neish and Green (1976) introduced the use of nuclear and satellite DNA base composition to the taxonomy of SaproZegnia. Beakes and colleagues (Beakes and Ford, 1983;Wood, 1988;Beakes, Wood and Burr, 1994) employed isozyme analysis to study S. parasitica populations in Great Britain. Their important studies support the hypothesis that a type of SaproZegnia with long hooks on its secondary cysts, is a, if not the most, common Saprolegnia on salmon.…”

Section: Introductionmentioning

confidence: 99%

Identification of Saprolegnia Spp. Pathogenic in Chinook Salmon : Final Report.

Whisler¹

1997

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“…Many pathogenic strains of Saprolegnia spp. isolated from fish lesions apparently lack a sexual stage (Beakes & Ford 1983) including these catfish isolates. One would assume that asexual reproduction or sexual propagation in homothallic strains may lead to clonal propagation, i.e.…”

Section: Discussionmentioning

confidence: 98%

“…Physiological properties of Saprolegnia have been used for the classification of different subgroups within a species. Studies with esterase isoenzyme patterns (Beakes & Ford 1983) and the relationships between growth rate and temperature (Willoughby & Copland 1984, Hatai et al 1990) identified different groups of fish lesion isolates. In this study, there were differences between the hyphal radial growth rate of Saprolegnia sp.…”

mentioning

confidence: 99%

Characterisation of Saprolegnia sp. isolates from channel catfish

Bangyeekhun¹,

Quiniou²,

Bly³

et al. 2001

Dis. Aquat. Org.

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Nineteen channel catfish isolates of Saprolegnia sp. obtained from 5 separate fish farms in Mississippi, which became affected by winter kill syndrome during 1991 and 1996, were investigated with respect to physiological characteristics and genetic variation. Isolates of S. parasitica from crayfish and S. diclina were included for comparison. Most strains of catfish isolates grew well at 20 and 30°C. Repeated zoospore emergence was found in catfish isolates of Saprolegnia sp. and S. parasitica, but not in S. diclina. Random amplification of polymorphic DNA polymerase chain reaction (RAPD-PCR) was applied for a further characterisation of the isolates. The RAPD analysis among Saprolegnia spp. isolates was constructed from 686 amplified products in 67 separable positions and indicated that the catfish isolates of Saprolegnia sp. are composed of 3 genetically distinct groups.KEY WORDS: Saprolegnia · Saprolegniosis · Fish disease · Random amplification of polymorphic DNA (RAPD) Resale or republication not permitted without written consent of the publisherDis Aquat Org 45: [53][54][55][56][57][58][59] 2001 signs of winter saprolegniosis (formerly termed winter kill syndrome). In the case of one fish, isolates were obtained from the eye and fin. All catfish were obtained from catfish farms, at least 50 miles (~80 km) apart, but located within the Mississippi Delta, USA. Isolates obtained in 1991 are designated CF91 and comprise CF91-1 (now deposited in the American Type Culture Collection; ATCC # 200048), CF91-2, CF91-4, CF91-5, CF91-6 and CF91-9. All 1991 isolates were collected from different fish in one pond at Dyche Plantation catfish farm (designated Farm 1, Table 1; Bly et al. 1992, wherein these isolates are referred to as CF1 through CF9). All other isolates collected from catfish were obtained in 1996 and are designated as CF96. CF96-1 through CF96-13 were obtained from different places of origin (see Table 1) in order to determine if geography had an effect on Saprolegnia spp. genetic variation. Four farms were sampled in 1996, TAM-AN (Farm 2), Holly Ridge (Farm 3), Topcat (Farm 4) and Higg (Farm 5). Other strains, i.e. S. parasitica (Spt) isolated from freshwater crayfish Astacus leptodactylus (Söderhäll et al. 1991) and S. diclina (Sdi; ATCC # 42062), were included for comparison. All isolates were maintained on PG-1 agar medium (Unestam 1965).Hyphal radial growth rate. The inoculum was prepared by cutting at the advancing edges of a young colony grown on PG-1 agar with a 6 mm diameter borer. The different Saprolegnia isolates were inoculated on a fresh PG-1 agar dish. The colony hyphal radial growth rates were determined as described by Trinci (1969) at 20 and 30°C. Comparisons of hyphal growth rate between isolates were made using a Student's t-test. Differences were considered significant at p ≤ 0.05.Repeated zoospore emergence. Repeated zoospore emergence was performed according to the method described by Diéguez-Uribeondo et al. (1994). Briefly, mycelia were grown in PG-1 drop cultures ...

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Esterase Isoenzyme Variation in the Genus Saprolegnia, with Particular Reference to the Fish-pathogenic S. diclina-parasitica Complex

Cited by 22 publications

References 22 publications

Prevalence of a single fish-pathogenic Saprolegnia sp. clone in Finland and Sweden

Prevalence of a single fish-pathogenic Saprolegnia sp. clone in Finland and Sweden

Identification of Saprolegnia Spp. Pathogenic in Chinook Salmon : Final Report.

Characterisation of Saprolegnia sp. isolates from channel catfish

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