Molt related mortalities of the Dungeness crab Cancer magister caused by a marine facultative ciliate Mesanophrys pugettensis

Morado, J. Frank; Giesecke, Ricardo; Syrjala, S. E.

doi:10.3354/dao038143

Cited by 19 publications

(20 citation statements)

References 18 publications

(24 reference statements)

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“…Morado et al (1999) suggested that Mesanophrys pugettensis enters the Dungeness crab via lesions in the epidermal surface associated with the moult cycle; inside they spread through the body and multiply to high densities in tissues and haemolymph. Hibbits & Sparks (1983) also suggested that the cuticle of the isopod Gnorimosphaeroma oregonensis is the location of initial ciliate invasion.…”

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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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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“…Dungeness crabs are susceptible to a variety of infective agents including a Chlamydia-like organism , a parasitic ciliate Me sanophrys pugettensis (Morado & Small 1994, Morado et al 1999, a rarely encountered Hematodinium-like parasitic dinoflagellate (Meyers & Burton 2009), and an unusual microsporidian, Nadelspora canceri (Olson et al 1994). The microsporidian N. canceri has unique needle-shaped spores and was originally described in Dungeness crabs from Alsea Bay, Oregon (Olson et al 1994), and was later identified in Dungeness crabs from Bodega Bay, California, to Gray's Harbor, Washington (Childers et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Ameson metacarcini sp. nov. (Microsporidia) infecting the muscles of Dungeness crabs Metacarcinus magister from British Columbia, Canada

Small

Meyer²,

Stentiford³

et al. 2014

Dis. Aquat. Org.

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The Dungeness crab Metacarcinus magister supports a large and valuable fishery along the west coast of North America. Since 1998, Dungeness crabs exhibiting pink-to orangecolored joints and opaque white musculature have been sporadically observed in low prevalence from the Fraser River delta of British Columbia, Canada. We provide histological, ultrastructural, and molecular evidence that this condition is caused by a new microsporidian parasite. Crabs displaying gross symptoms were confirmed to have heavy infections of ovoid-shaped microsporidian spores (~1.8 × 1.4 µm in size) within muscle bundles of the skeletal musculature. The parasite apparently infected the outer periphery of each muscle bundle, and then proliferated into the muscle fibres near the centre of each infected bundle. Light infections were observed in heart tissues, and occasionally spores were observed within the fixed phagocytes lining the blood vessels of the hepatopancreas. Transmission electron microscopy (TEM) revealed multiple life stages of a monokaryotic microsporidian parasite within the sarcoplasm of muscle fibres. Molecular analysis of partial small subunit rRNA sequence data from the new species revealed an affinity to Ameson, a genus of Microsporidia infecting marine crustaceans. Based on morphological and molecular data, the new species is distinct from Nadelspora canceri, a related microsporidian that also infects the muscles of this host. At present, little is known about the distribution, seasonality, and transmission of A. metacarcini in M. magister.

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“…This phenomenon is probably adaptive by avoiding exposure of the gammarids to pathogens during ecdysis, a period of high susceptibility to infection (Le Moullac et al 1997;Morado et al 1999). This plastic change in time to ecdysis in response to water quality is independent of levels of immune defences.…”

Section: Discussionmentioning

confidence: 99%

Condition-dependent ecdysis and immunocompetence in the amphipod crustacean, Gammarus pulex

et al. 2010

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The exoskeleton of arthropods forms an efficient protection against pathogens, but this first line of defence is periodically weakened during ecdysis, increasing the opportunity for surrounding pathogens to invade the body cavity. Since the richness of pathogens in the environment can be spatially and temporally variable, arthropods may have a fitness advantage in moulting in a place and time of low infection risk. Consistent with this hypothesis, we found that the amphipod crustacean, Gammarus pulex , exhibits temporal adjustment of the moult cycle in response to elevated risks of infection. Interestingly, this phenomenon is variable between two populations and independent of levels of immune defences. These results suggest that plasticity of the moult cycle in response to elevated risks of infection is adaptive and may result from adaptation to local variations in the risk of infection.

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Molt related mortalities of the Dungeness crab Cancer magister caused by a marine facultative ciliate Mesanophrys pugettensis

Cited by 19 publications

References 18 publications

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

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

Ameson metacarcini sp. nov. (Microsporidia) infecting the muscles of Dungeness crabs Metacarcinus magister from British Columbia, Canada

Condition-dependent ecdysis and immunocompetence in the amphipod crustacean, Gammarus pulex

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