Investigations on the role of the salmon louse, Lepeophtheirus salmonis (Caligidae), as a vector in the transmission of Aeromonas salmonicida subsp. salmonicida

2016 ◽  
Vol 39 (10) ◽  
pp. 1165-1178 ◽  
Author(s):  
C W Novak ◽  
D L Lewis ◽  
B Collicutt ◽  
K Verkaik ◽  
D E Barker
Keyword(s):  
Aeromonas Salmonicida ◽  
Lepeophtheirus Salmonis ◽  
Salmon Louse

Diel vertical distribution of early marine phase juvenile pink salmon (Oncorhynchus gorbuscha) and behaviour when exposed to salmon louse (Lepeophtheirus salmonis)

2011 ◽  
Vol 89 (9) ◽  
pp. 796-807 ◽  
Author(s):  
S. Tang ◽  
A.G. Lewis ◽  
M. Sackville ◽  
L. Nendick ◽  
C. DiBacco ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Pink Salmon ◽  
Distribution Patterns ◽  
Oncorhynchus Gorbuscha ◽  
Lepeophtheirus Salmonis ◽  
Night Time ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Salmon Louse ◽  
Seawater Acclimation

We observed diel vertical migration patterns in juvenile pink salmon ( Oncorhynchus gorbuscha (Walbaum, 1792)) and tested the hypothesis that fish behaviour is altered by exposure to sea lice copepodids. Experiments involved replicated field deployments of a large (9 m) plankton column, which provided a vertical distribution enclosure under natural light and salinity conditions. Diel vertical distributions of juvenile pink salmon were observed during the first 3 weeks of seawater acclimation in both the presence and the absence of the ectoparasitic salmon louse ( Lepeophtheirus salmonis (Krøyer, 1838)). Immediately upon entering seawater, juvenile pink salmon preferred the top 1 m of the water column, but they moved significantly deeper down the vertical water column as seawater acclimation time increased. A significant diel migration pattern was observed, which involved a preference for the surface at night-time, compared with daytime. When fish in the column were exposed to L. salmonis copepodids for 3 h, 43%–62% of fish became infected, fish expanded their vertical distribution range, and significant changes in vertical distribution patterns were observed.

scholarly journals 4-hydroxyphenylpyruvate dioxygenase thermolability is responsible for temperature-dependent melanogenesis inAeromonas salmonicidasubsp.salmonicida

2018 ◽  
Author(s):  
Yunqian Qiao ◽  
Jiao Wang ◽  
He Wang ◽  
Baozhong Chai ◽  
Chufeng Rao ◽  
...  
Keyword(s):  
Cold Water ◽  
Biological Significance ◽  
Adaptive Strategy ◽  
Aeromonas Salmonicida ◽  
Temperature Dependent ◽  
Ideal Model ◽  
Melanin Production ◽  
Water Fish ◽  
Insight Into

AbstractAeromonas salmonicidasubsp.salmonicida(A.s.s) is a major pathogen affecting fisheries worldwide. It is a well-known member of the pigmentedAeromonasspecies, which produces melanin at ≤ 22 °C. However, melanogenesis decreases as the culture temperature increases and is completely suppressed at 30-35 °C while bacterial growth is not affected. The mechanism and biological significance of this temperature-dependent melanogenesis are not clear. Heterologous expression of anA.s.s.4-hydroxyphenylpyruvate dioxygenase (HppD), the most crucial enzyme in the HGA-melanin synthesis pathway, results in thermosensitive pigmentation inEscherichia coli, suggesting that HppD plays a key role in this process. In the current study, we demonstrated that the extreme thermolability of HppD is responsible for the temperature-dependent melanization ofA.s.s.Substitutions in three residues, Ser18, Pro103, or Leu119 of HppD fromA.s.sincreases the thermolability of this enzyme and results in temperature-independent melanogenesis. Moreover, replacing the corresponding residues of HppD fromAeromonasmedia strain WS, which forms pigment independent of temperature, with those ofA.s.sHppD leads to thermosensitive melanogenesis. Structural analysis suggested that mutations at these sites, especially at position P103, can strengthen the secondary structure of HppD and greatly improve its thermal stability. In addition, we found that HppD sequences of allA.s.sisolates are identical and that two of the three residues are completely conserved withinA.s.sisolates, which clearly distinguishes these from otherAeromonasstrains. We suggest that this property represents an adaptive strategy to the psychrophilic lifestyle ofA.s.s.ImportanceAeromonas salmonicidasubsp.salmonicida(A.s.s) is the causative agent of furunculosis, a bacterial septicemia of cold water fish of theSalmonidaefamily. As it has a well-defined host range,A.s.shas become an ideal model to investigate the co-evolution of host and pathogen. For many pathogens, melanin production is associated with virulence. Although other species ofAeromonascan produce melanin,A.s.sis the only member of this genus that has been reported to exhibit temperature-dependent melanization. Here we demonstrate that thermosensitive melanogenesis inA.s.sstrains is due to the thermolability of 4-hydroxyphenylpyruvate dioxygenase (HppD). The strictly conservedhppDsequences amongA.s.sand the exclusive thermosensitive pigmentation of these strains might provide insight into the role of melanin in the adaptation to a particular host, and offer a novel molecular marker to readily differentiateA.s.sstrains from otherA. salmonicidasubspecies andAeromonasspecies.

scholarly journals Rainbow trout Oncorhynchus mykiss skin responses to salmon louse Lepeophtheirus salmonis: From copepodid to adult stage

2020 ◽  
Vol 103 ◽  
pp. 200-210 ◽  
Author(s):  
Sussie Dalvin ◽  
Louise v.G. Jørgensen ◽  
Per W. Kania ◽  
Sindre Grotmol ◽  
Kurt Buchmann ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Adult Stage ◽  
Lepeophtheirus Salmonis ◽  
Salmon Louse ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Skin Responses

scholarly journals Ultrastructure of the cuticle of the chalimus larva of the salmon louse Lepeophtheirus salmonis (Krøyer, 1837) (Copepoda: Caligidae)

2000 ◽  
Vol 69 (1-2) ◽  
pp. 39-49 ◽  
Author(s):  
J.E. Bron ◽  
A.P. Shinn ◽  
C. Sommerville
Keyword(s):  
Lepeophtheirus Salmonis ◽  
Free Living ◽  
Salmon Louse ◽  
Parasitic Species

The cuticle of the chalimus II stage of Lepeophtheirus salmonis (Copepoda: Caligidae) comprised a four-layered epicuticle with a pronounced fuzzy coat which was separated from the outer and inner procuticles by a layer of transitional procuticle. The cuticle is underlain by a single-layered epidermis which overlies integumental glands and chromatophores. The structure of this cuticle is very similar to that described for free-living copepods and does not display the modifications associated with more highly transformed parasitic species.

Genetic variation in resistance of Atlantic salmon (Salmo salar) to the salmon louse Lepeophtheirus salmonis

Aquaculture ◽  
2005 ◽  
Vol 247 (1-4) ◽  
pp. 145-151 ◽  
Author(s):  
Kari Kolstad ◽  
Peter Andreas Heuch ◽  
Bjarne Gjerde ◽  
Trygve Gjedrem ◽  
Ragnar Salte
Keyword(s):  
Genetic Variation ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Lepeophtheirus Salmonis ◽  
Salmon Louse ◽  
Atlantic Salmon Salmo Salar
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