Properties of Extracellular Enzymes from <i>Aphanomyces astaci</i> and Their Relevance in the Penetration Process of Crayfish Cuticle

Söderhäll, Kenneth; Unestam, Torgny

doi:10.1111/j.1399-3054.1975.tb03883.x

Cited by 48 publications

(17 citation statements)

References 27 publications

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“…In inoculated sugarbeet seedlings, the protease activities were detected prior to or concomitant with the onset of disease symptoms and the activities were capable of digesting protein extracted from sugarbeet hypocotyls. Also, Soederhaell and Unestam (1975) found protease activity in culture filtrates from the crayfish plague parasite, Aphanomyces astaci. In addition, Dieguez-Uribeondo and Cerenius (1988) reported that species of Aphanomyces that attack fish (e.g., A. invidans) and crayfish (e.g., A. astaci) have been shown to produce abundant extracellular protease.…”

Section: Discussionmentioning

confidence: 99%

Antifungal activity of sodium chloride on Saprolegnia diclina and Aphanomyces sp.

Ali

2013

Acta Mycol

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Sixteen identified and three unidentified species belonging to six genera of zoosporic fungi were isolated from forty water samples which were collected from different fish and fish hatcheries farms at Abbassa city, Sharkiya governorate, Egypt, using sesame seeds baiting technique at 20±2°C. Saprolegnia and Achlya contributed the broadest spectra of species diversity amongst the other genera of zoosporic fungi. Saprolegnia diclina and Aphanomyces sp. were the most prevalent species of zoosporic fungi. The abundance of zoosporic fungal species in these aquacultures was correlated with some physicochemical characteristics of the water samples. The two dominant species of zoosporic fungi were tested for their tolerance of NaCl solution and its impact on some morphological and metabolic activities of these fungi. Saprolegnia diclina tolerated concentrations of NaCl solution till 12000 μg/ml whereas the maximum resistance of Aphanomyces sp. was 8000 μg/ml. The examined morphological aspects of the two studied fungal species, which included the colony diameters, the vegetative hyphae, zoosporogenesis, zoospores discharge, sexual reproductive structures and gemmae formation, were generally affected depending upon the tested fungal species and the applied dose of NaCl solution. The low treatments of NaCl solution were significantly stimulative compared with the control for protease production by S. diclina but higher doses were significantly suppressive. A significant decline in protease activity at all applications was found when Aphanomyces sp. was treated with NaCl solution. The total free amino acids and total protein content of S. diclina and Aphanomyces sp. mycelia were almost significantly increased relative to untreated controls at the low dose of NaCl solution and they were significantly dropped at the higher concentrations by the two zoosporic fungi.

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Section: Discussionmentioning

confidence: 99%

Antifungal activity of sodium chloride on Saprolegnia diclina and Aphanomyces sp.

Ali

2013

Acta Mycol

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“…Many marine bacterial, fungal and protozoan pathogens secrete proteases during in vitro culture, suggesting that protease release could be important in pathogenesis. Examples include the salmon pathogen Aeromonas salmonicida (Rockey et al 1988), the crayfish pathogen Aphanomyces astaci (Söderhäll & Unestam 1975), and the oyster parasite Perkinsus marinus . Uronema marinum, a histophagous parasitic ciliate of the olive flounder Paralichthys olivaceus, has also been reported to secrete proteases during in vitro culture Identification and partial characterisation of metalloproteases secreted by a Mesanophrys-like ciliate parasite of the Norway lobster Nephrops norvegicus (Lee et al 2003); in this case, secreted proteases may be directly responsible for many of the clinical symptoms associated with the disease, such as tissue necrosis.…”

Section: Introductionmentioning

confidence: 99%

Identification and partial characterisation of metalloproteases secreted by a Mesanophrys-like ciliate parasite of the Norway lobster Nephrops norvegicus

Small¹,

Neil²,

Taylor³

et al. 2005

Dis. Aquat. Org.

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A ciliate parasite, tentatively identified as Mesanophrys sp. of Norway lobstersNephrops norvegicus, is demonstrated to secrete several proteases into the culture medium (modified Nephrops saline). Analyses using substrate-impregnated sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed 12 activity bands differing greatly in mobility in the gels. The complete inhibition of proteolytic activity by 1,10-phenanthroline indicated that the proteases are of the metallo class. The proteases were active at the physiological temperature (8°C) and haemolymph pH (7.8) of the host. The proteases were selective in the degradation of several host proteins, including the myosin heavy chain, which is a major structural component of lobster muscle. Consequently, these proteases may have important roles in several aspects of the host -parasite interaction including invasion, nutrient uptake by the ciliate, and pathogenesis.KEY WORDS: Ciliate · Parasite · Proteases · Secreted · Pathology Resale or republication not permitted without written consent of the publisherDis Aquat Org 67: [225][226][227][228][229][230][231] 2005 ( Lee et al. 2003); in this case, secreted proteases may be directly responsible for many of the clinical symptoms associated with the disease, such as tissue necrosis.Several reports of Mesanophrys spp. infections in crustaceans have indicated that these ciliates infiltrate and consume host tissues and haemocytes (Poisson 1930, Bang et al. 1972, Messick & Small 1996. The discovery of a Mesanophrys-like parasitic ciliate infecting Norway lobsters Nephrops norvegicus, and isolation of the ciliate via in vitro cultivation, has allowed proteolytic factors that may play a role in the parasite's establishment and proliferation to be investigated. This paper reports on the characterisation of these proteases, and suggests ways in which they may be involved in the pathogenesis of ciliate disease in lobsters. MATERIALS AND METHODSIsolation and cultivation of the ciliate parasite. Routine screening of Nephros norvegicus from the Clyde Sea area for the parasitic dinoflagellate Hematodinium sp. led to the discovery and identification of a ciliate infection in several Norway lobsters (Small et al. 2005). Haemolymph samples were withdrawn aseptically from the base of the fifth pereiopod using a 1 ml disposable syringe and 25-gauge needle following sterilisation of the cuticle with 70% (v/v) ethanol. Ciliate infections were diagnosed by viewing haemolymph smears using light microscopy. Parasitic ciliates were isolated in 3.5 cm well plates with 0.2 ml infected haemolymph added to 5 ml culture medium in each well. The culture medium comprised 10% (v/v) ) and streptomycin (10 µg ml -1 ) were added to inhibit bacterial contamination. The medium was filter-sterilised (0.2 µm) after the addition of all constituents. Cultures were incubated at 8°C. Serial subculturing gave rise to axenic cultures.Experimental subcultures for protease analyses were initiated with the addition of 1 × 10 5 ciliate...

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“…Fungal and oomycete pathogens on insects and crustaceans secrete several types of lytic enzymes, including lipases, proteases and chitinases (Unestam 1966, Söderhäll & Unestam 1975, Persson et al 1984, Samuels et al 1989, Clarkson & Charnley 1996, Dieguez-*Corresponding author. E-mail: lage.cerenius@ebc.uu.se Uribeondo & Cerenius 1998, Vilcinscas & Götz 1999.…”

Section: Introductionmentioning

confidence: 99%

Analysis of chitinase expression in the crayfish plague fungus Aphanomyces astaci

Andersson¹,

Cerenius²

2002

Dis. Aquat. Org.

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Chitinase, as determined by enzymatic activity in the growth medium and by transcription of the chitinase gene AaChi1, is expressed at a high level during vegetative growth of the crayfish pathogen Aphanomyces astaci and expression is not further stimulated by chitin. Expression is not detected in zoospores and it does not increase to high levels until late during germination. Upon sporulation, chitinase expression increases to levels comparable with those seen in fast-growing mycelium. This pattern of chitinase expression is a common feature of strains representing all currently known genotypes of A. astaci, suggesting that it is an adaptation to the exclusively parasitic life-style of this species. In contrast, other Aphanomyces spp. including the saprophytes, A. laevis and A. stellatus, produce significant amounts of chitinase only in the presence of chitin. The pattern of chitinase expression is one of very few qualitative physiological characteristics known which can distinguish A. astaci from other parasitic and saprophytic species and may thus be of practical use for identification.

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Properties of Extracellular Enzymes from Aphanomyces astaci and Their Relevance in the Penetration Process of Crayfish Cuticle

Cited by 48 publications

References 27 publications

Antifungal activity of sodium chloride on Saprolegnia diclina and Aphanomyces sp.

Antifungal activity of sodium chloride on Saprolegnia diclina and Aphanomyces sp.

Identification and partial characterisation of metalloproteases secreted by a Mesanophrys-like ciliate parasite of the Norway lobster Nephrops norvegicus

Analysis of chitinase expression in the crayfish plague fungus Aphanomyces astaci

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