Effects of bacteria on the growth of an amoeba infecting the gills of turbot

Paniagua, E.; Paramá, A.; Iglesias, R.; Sanmartín, M. L.; Leiro, J.

doi:10.3354/dao045073

Cited by 12 publications

(11 citation statements)

References 23 publications

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“…This result suggests that at a low density, Aeromonas spp . is internalized by amoebae or that Aeromonas may be used as a food source by the amoebae A. castellanii , as has been suggested (Paniagua et al. , 2001).…”

Section: Discussionmentioning

confidence: 81%

Aeromonas–Acanthamoeba interaction and early shift to a viable but nonculturable state of Aeromonas by Acanthamoeba

et al. 2008

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Aims: To investigate the hypothesis that amoeba may comprise a significant environmental reservoir for Aeromonas, Acanthamoeba-Aeromonas interaction experiments were performed. Methods and Results: Acanthamoeba were grown in monoculture and co-cultures with three different species of Aeromonas. Survival, invasion and viable but nonculturable state experiments were performed. We showed that at a low initial bacterial cell density, growth of Aeromonas spp. was inhibited by Acanthamoeba castellanii, while A. castellanii growth was unaffected. In contrast, a high initial bacterial cell density, Aeromonas hydrophila AEW44 and Aeromonas veronii biovar sobria AEW104 suppressed the growth of A. castellanii. Fluorescent and phase-contrast microscopic observations of GFP tagged Aer. hydrophila AEW44 demonstrated that the bacterial cells aggregated on A. castellanii cells after 15 min of incubation and internalized. Aeromonas hydrophila AEW44 cells were found to be actively moving. Interestingly, Aer. hydrophila AEW44 cells shifted more rapidly to a viable but nonculturable form when co-cultured with A. castellanii than in monoculture. Conclusions: We demonstrated that Aeromonas spp. are able to interact with and to infect the protozoan A. castellanii under laboratory conditions. Significance and Impact of the Study: Free-living amoeba might play a role as reservoir for Aeromonas, and thus may increase the transmission of Aeromonas by acting as a vehicle.

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Section: Discussionmentioning

confidence: 81%

Aeromonas–Acanthamoeba interaction and early shift to a viable but nonculturable state of Aeromonas by Acanthamoeba

et al. 2008

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“…Previous researchers suggest that other infectious amoebae may feed on gill bacteria (Noble et al 1997) and perhaps attain bloom populations in the presence of abundant food organisms (Kent et al 1988). In vitro growth of trophozoites of a Platyamoeba strain isolated from the diseased gill tissues of cultured turbot increased considerably in the presence of Aeromonas hydrophila, Vibrio natriegens, Pseudomonas nautica and Escherichia coli (Paniagua et al 2001). Similarly, the number of Acanthamoeba castellanii and A. polyphaga were enhanced by cocultivation with the Gram negative bacteria, Xanthomonas maltophilia, Flavobacterium breve and Pseudomonas paucimobilis (Bottone et al 1992).…”

Section: Discussionmentioning

confidence: 99%

Influence of salmonid gill bacteria on development and severity of amoebic gill disease

Embar-Gopinath¹,

Bütler²,

Nowak³

2005

Dis. Aquat. Org.

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ABSTRACT:The relationship between salmonid gill bacteria and Neoparamoeba sp., the aetiological agent of amoebic gill disease (AGD) was determined in vivo. Fish were divided into 4 groups and were subjected to following experimental infections: Group 1, amoebae only; Group 2, Staphylococcus sp. and amoebae; Group 3, Winogradskyella sp. and amoebae; Group 4, no treatment (control). Fish (Groups 1, 2 and 3) were exposed to potassium permanganate to remove the natural gill microflora prior to either bacterial or amoebae exposure. AGD severity was quantified by histological analysis of gill sections to determine the percentage of lesioned filaments and the number of affected lamellae within each lesion. All amoebae infected groups developed AGD, with fish in Group 3 showing significantly more filaments with lesions than other groups. Typically lesion size averaged between 2 to 4 interlamellar units in all AGD infected groups. The results suggest that the ability of Neoparamoeba sp. to infect filaments and cause lesions might be enhanced in the presence of Winogradskyella sp. The possibility is proposed that the prevalence of more severe AGD is due to the occurrence of Winogradskyella sp. at high concentrations on the gills.KEY WORDS: Neoparamoeba · Winogradskyella · AGD · Potassium permanganate · Protozoan diseases · Salmon diseases · Amoeba · Bacteria Resale or republication not permitted without written consent of the publisherDis Aquat Org 67: [55][56][57][58][59][60] 2005 MATERIALS AND METHODS Fish. Atlantic salmon Salmo salar L. (n = 72; mean weight = 88 g) were acclimatised to sea water (35 ‰, 1 µm filtered) over a week in 6 identical recirculating systems each consisting of three 70 l tanks (n = 4 fish per tank) and a 70 l reservoir. A sentinel population (n = 12) of the same body weight was acclimatised in a static tank (210 l). Following acclimatisation, fish in the recirculating systems were divided into 3 treatment groups (n = 12 fish per treatment). Each treatment was duplicated. The 4th group was the sentinel population (n = 12). Fish in Group 1 were exposed to amoebae only (positive control); Group 2, Gram positive bacteria (Staphylococcus sp.) and amoebae; Group 3, Gram negative bacteria (Winogradskyella sp.) and amoebae; Group 4 did not receive any treatment. Sea water temperature was maintained at 16 ± 0.5°C, pH 8.2, dissolved oxygen 7.6 mg l -1 , salinity 35 ‰ and total ammonia-nitrogen below 0.2 mg l -1 . Sufficient air supply was maintained in the tanks throughout the experiment by using aerators.Neoparamoeba sp. isolation. Neoparamoeba sp. were harvested from the AGD affected Atlantic salmon held in the Aquaculture Centre, University of Tasmania, Launceston by a method described by Morrison et al. (2004). In brief, infected gills were removed from AGD affected Atlantic salmon after euthanasia (anaesthetic overdose at 20 ml l -1 Aqui-S ® ). Gills were transported to the laboratory in sterile sea water (SS) containing antibiotic and antimycotic solution (5% v/v 5000 IU ml -1 penicillin and 5 mg...

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“…Hence, the well-known predator of bacteria would become a prey to be parasitized. Therefore, A. salmonicida strains virulent for fish have also been demonstrated to be virulent for amoeba (Paniagua et al, 2001;Daher et al, 2011), and it has been confirmed with our wt (JF2267) and ΔascV (JF2747) mutant strains that this cytotoxic effect was associated with the T3SS (Froquet et al, 2007). For example, in V. parahaemolyticus, it has been demonstrated that the T3SS-2 promotes survival of the bacterium in the interaction with diverse protist taxa and that the enhanced persistence is due to T3SS-2 effectors mediated cytotoxicity [some of which being homologous to A. salmonicida effectors (Table 1)] and facultative parasitism of V. parahaemolyticus on coexisting protists (Matz et al, 2011).…”

Section: The Origin Of the T3ss-induced Virulence Of A Salmonicida -mentioning

confidence: 99%

Aeromonas salmonicida subsp. salmonicida in the light of its type‐three secretion system

Bergh

Frey

2013

Microbial Biotechnology

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Aeromonas salmonicida subsp. salmonicida is an important pathogen in salmonid aquaculture and is responsible for the typical furunculosis. The type-three secretion system (T3SS) is a major virulence system. In this work, we review structure and function of this highly sophisticated nanosyringe in A. salmonicida. Based on the literature as well as personal experimental observations, we document the genetic (re)organization, expression regulation, anatomy, putative functional origin and roles in the infectious process of this T3SS. We propose a model of pathogenesis where A. salmonicida induces a temporary immunosuppression state in fish in order to acquire free access to host tissues. Finally, we highlight putative important therapeutic and vaccine strategies to prevent furunculosis of salmonid fish.

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Effects of bacteria on the growth of an amoeba infecting the gills of turbot

Cited by 12 publications

References 23 publications

Aeromonas–Acanthamoeba interaction and early shift to a viable but nonculturable state of Aeromonas by Acanthamoeba

Aeromonas–Acanthamoeba interaction and early shift to a viable but nonculturable state of Aeromonas by Acanthamoeba

Influence of salmonid gill bacteria on development and severity of amoebic gill disease

Aeromonas salmonicida subsp. salmonicida in the light of its type‐three secretion system

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