Does Ralstonia eutropha, rich in poly‐β hydroxybutyrate (PHB), protect blue mussel larvae against pathogenic vibrios?

• Published in: Journal of Fish Diseases
• Main Authors: Van Hung, Nguyen, Bossier, Peter, Hong, Nguyen Thi X, Ludeseve, Christine, Garcia‐Gonzalez, Linsey, Nevejan, Nancy, De Schryver, Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Biology and Life Sciences; Mytilus edulis; poly-beta-hydroxybutyrate; Vibrio; virulence factors; GNOTOBIOTIC ARTEMIA-FRANCISCANA; OYSTER CRASSOSTREA-GIGAS; FLAGELLAR MOTILITY; MARINE-BACTERIA; PACIFIC OYSTER; GROWTH; PERFORMANCE; ACID; ENVIRONMENT; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://biblio.ugent.be/publication/8650913; http://hdl.handle.net/1854/LU-8650913; https://doi.org/10.1111/jfd.12981; https://biblio.ugent.be/publication/8650913/file/8650917

The natural amorphous polymer poly-beta-hydroxybutyrate (PHB-A: lyophilized Ralstonia eutropha containing 75% PHB) was used as a biological agent to control bacterial pathogens of blue mussel (Mytilus edulis) larvae. The larvae were supplied with PHB-A at a concentration of 1 or 10 mg/L for 6 or 24 hr, followed by exposure to either the rifampicin-resistant pathogen Vibrio splendidus or Vibrio coralliilyticus at a concentration of 10(5) CFU/ml. Larvae pretreated 6 hr with PHB-A (1 mg/L) survived a Vibrio challenge better relative to 24 hr pretreatment. After 96 hr of pathogen exposure, the survival of PHB-A-treated mussel larvae was 1.41- and 1.76-fold higher than the non-treated larvae when challenged with V. splendidus and V. coralliilyticus, respectively. Growth inhibition of the two pathogens at four concentrations of the monomer beta-HB (1, 5, 25 and 125 mM) was tested in vitro in LB35 medium, buffered at two different pH values (pH 7 and pH 8). The highest concentration of 125 mM significantly inhibited the pathogen growth in comparison to the lower levels. The effect of beta-HB on the production of virulence factors in the tested pathogenic Vibrios revealed a variable pattern of responses.