Neoparamoeba perurans loses virulence during clonal culture

Bridle, Andrew R.; Davenport, Danielle; Crosbie, Philip; Polinski, Mark P.; Nowak, Barbara F.

doi:10.1016/j.ijpara.2015.04.005

Cited by 37 publications

(47 citation statements)

References 17 publications

(28 reference statements)

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“…; Bridle et al . ). High‐molecular‐weight antigenic (HMWA) glycoproteins that appear to be anchored into the amoeba plasma membrane, identified by immunogold labelling are present within an apparent cell membrane glycocalyx (Villavedra et al .…”

Section: Discussionmentioning

confidence: 97%

“…; Bridle et al . ) in salmon gill epithelial cell cultures. These data correspond with the current observations that tight membrane–membrane interaction is not necessary for induction of pavement cell epithelial necrosis by P. perurans .…”

Section: Discussionmentioning

confidence: 99%

“…This suggests the existence of cellular glycocalyx, but can also be a result of contraction of the amoebae away from the epithelial cells during the tissue handling as mentioned above (Roubal et al 1989). Amoebic attachment to the gill has been a focus for many studies (Butler & Nowak 2004;Lee et al 2006;Bridle et al 2015). High-molecular-weight antigenic (HMWA) glycoproteins that appear to be anchored into the amoeba plasma membrane, identified by immunogold labelling are present within an apparent cell membrane glycocalyx (Villavedra et al 2010).…”

Section: Discussionmentioning

confidence: 99%

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Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Wiik‐Nielsen

Kolstad

et al. 2016

Journal of Fish Diseases

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Amoebic gill disease (AGD) caused by the ectoparasite Paramoeba perurans affects several cultured marine fish species worldwide. In this study, the morphology and ultrastructure of P. perurans in vitro and in vivo was investigated using scanning and transmission electron microscopy (SEM and TEM, respectively). Amoebae cultures contained several different morphologies ranging from a distinct rounded cell structure and polymorphic cells with pseudopodia of different lengths and shapes. SEM studies of the gills of AGD-affected Atlantic salmon, Salmo salar L., revealed the presence of enlarged swellings in affected gill filaments and fusion of adjacent lamellae. Spherical amoebae appeared to embed within the epithelium, and subsequently leave hemispherical indentations with visible fenestrations in the basolateral surface following their departure. These fenestrated structures corresponded to the presence of pseudopodia which could be seen by TEM to penetrate into the epithelium. The membrane-membrane interface contained an amorphous and slightly fibrous matrix. This suggests the existence of cellular glycocalyces and a role for extracellular products in mediating pathological changes in amoebic gill disease.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Wiik‐Nielsen

Kolstad

et al. 2016

Journal of Fish Diseases

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“…The nucleic acid pellet was rinsed twice with 70% ethanol and resuspended in 50 µl of TE buffer (10 mM Tris, 1 mM EDTA, pH 8). Real-time PCR assays for Neoparamoeba perurans were conducted to quantify amoeba abundance for each sample using a CFX Connect PCR Detection System (Bio-Rad) to detect an N. perurans-specific 18S rRNA sequence as described by Bridle et al (2010), but with modifications (Bridle et al 2015). ).…”

Section: Amoeba Quantificationmentioning

confidence: 99%

Depth distribution of the amoebic gill disease agent, Neoparamoeba perurans, in salmon sea-cages

Wright¹,

Nowak²,

Oppedal³

et al. 2015

Aquacult. Environ. Interact.

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Identifying where and when parasites occur in farming environments is vital to understand transmission dynamics and develop preventative measures that reduce host−parasite encounters. A major parasite concern for Atlantic salmon farming is Neoparamoeba perurans, a marine amoeba that causes the potentially fatal amoebic gill disease (AGD), for which few control options exist. We explored whether free-living N. perurans abundance differs among depths in commercial Atlantic salmon Salmo salar sea-cages. Water samples collected from the surface to 10 m depth at multiple cage sites and times, and subsequently subjected to qPCR analysis, revealed that N. perurans abundance was influenced by depth at the time of year when amoeba numbers were highest, with more amoebae in surface waters. No distinct depth patterns were observed when amoebae were in low abundance. Across all times, temperature and salinity were largely homogeneous throughout cage depths. Possible factors explaining the presence of amoebae at the surface are discussed. Our results suggest that excluding caged salmon from upper cage depths where N. perurans is more abundant could be an effective management strategy to reduce the speed at which initial infections occur and delay the development of AGD outbreaks.

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“…During in vivo challenge experiments, an artificially elongated duration of attachment, during which parasitic amoeba could theoretically spend more time colonizing the gill substrate (Wiik‐Nielsen et al., ) than completing the natural emigration to the surrounding sea water, may lead to an increased level of disease progression and therefore an elevated immune response, which may not be comparable to the speed of disease progression found in the field. Nonetheless, with reported loss of virulence seen in cultured N. perurans possibly due to lack of attachment to gills (Bridle, Davenport, Crosbie, Polinski, & Nowak, ), increased attachment due to the use of isoeugenol‐based anaesthetics may help mitigate this problem, if similar attachment processes are involved.…”

Section: Discussionmentioning

confidence: 99%

Effect of repeated exposure to AQUI‐S^® on the viability and growth of Neoparamoeba perurans

Chance

Allcock

Secombes

et al. 2017

Journal of Fish Diseases

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There have been recent efforts amongst immunologists to develop approaches for following individual fish during challenges with viral and bacterial pathogens. This study contributes to assessing the feasibility of using such approaches to study amoebic gill disease (AGD). Neoparamoeba perurans, agent of AGD, has been responsible for widespread economic and fish loss in salmonid aquaculture. With the emergence of AGD in Europe, research into infection dynamics and host response has increased. This study investigated the effect of repeat exposure to anaesthesia, a necessary requirement when following disease progression in individual fish, on N. perurans. In vitro cultures of N. perurans were exposed every 4 days over a 28‐day period to AQUI‐S® (isoeugenol), a popular anaesthetic choice for AGD challenges, at a concentration and duration required to sedate post‐smolt salmonids. Population growth was measured by sequential counts of amoeba over the period, while viability of non‐attached amoeba in the culture was assessed with a vital stain. AQUI‐S® was found to be a suitable choice for in vivo ectoparasitic challenges with N. perurans during which repetitive anaesthesia is required for analysis of disease progression.

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Neoparamoeba perurans loses virulence during clonal culture

Cited by 37 publications

References 17 publications

Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Depth distribution of the amoebic gill disease agent, Neoparamoeba perurans, in salmon sea-cages

Effect of repeated exposure to AQUI‐S^® on the viability and growth of Neoparamoeba perurans

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Neoparamoeba perurans loses virulence during clonal culture

Cited by 37 publications

References 17 publications

Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills

Depth distribution of the amoebic gill disease agent, Neoparamoeba perurans, in salmon sea-cages

Effect of repeated exposure to AQUI‐S® on the viability and growth of Neoparamoeba perurans

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Effect of repeated exposure to AQUI‐S^® on the viability and growth of Neoparamoeba perurans