Identification of a marine antagonistic strain JG1 and establishment of a polymerase chain reaction detection technique based on the gyrB gene

Abstract

A marine antagonistic bacterium, JG1, was isolated from rearing water of healthy turbot (Scophthalmus maximus) in Qingdao, China. Strain JG1 was Gramnegative, straight rod and motile by polar £agella. The colony, when cultured for 24 h under room temperature, produced a yellow pigment. On the basis of morphological, physiological and biochemical characteristics, along with 16S rDNA sequence analysis, JG1 was identi¢ed as Pseudoalteromonas £avipulchra. JG1 had good inhibitory e¡ects on several bacterial pathogens of aquaculture in the genusVibrio (V. anguillarum, V. alginolyticus,V. campbellii, V. harveyi,V. mimicus, V. parahaemolyticus and V. tubiashii) and Aeromonas (A. hydrophila and A. salmonicida). No mortality occurred 14 days after zebra ¢sh and 7 days after mantis shrimp were intraperitoneally injected with JG1 at 10 6 CFU per animal, and 7 days after scallop and clam were immersed in JG1 at 10 7 CFU mL À 1 . A good antagonistic e¡ect on several bacterial pathogens and nontoxicity to the above-mentioned animals make JG1 a potential probiotic in aquaculture. In addition, a fast detection technique based on polymerase chain reaction ampli¢cation of the gyrB gene was established to allow us to determine the fate of JG1 when it is applied in aquaculture in the future.

Purification and characterization of antibacterial compounds of Pseudoalteromonas flavipulchra JG1

“…Antibacterial spectrum of JG1 P. flavipulchra JG1 was originally isolated from rearing water of healthy turbot (Scophthalmus maximus) in Qingdao, China, and the bacterial culture had excellent inhibitory effects against bacterial pathogens of aquaculture including species of Vibrio and Aeromonas (Jin et al, 2010). In this study, JG1 was found to inhibit another 17 of the 19 Vibrio strains tested, the exceptions being V. proteolyticus LMG 3772 and V. xuii LMG 21346, and five Bacillus strains.…”

“…P. flavipulchra JG1, which has a golden yellow colour, has excellent antibacterial activities, especially against pathogens in marine aquaculture. Since JG1 is an indigenous bacterium in aquaculture water which is harmless to aquatic animals (Jin et al, 2010), and its antibacterial activity is similar to that of some antibiotics, JG1 and/or its products have the potential to be used as probiotics or antibiotics in aquaculture.…”

“…Vibrio harveyi, Vibrio mimicus, Vibrio parahaemolyticus and Vibrio tubiashii, and Aeromonas hydrophila and Aeromonas salmonicida, and was nontoxic to zebra fish and mantis shrimp (Jin et al, 2010). P. flavipulchra strain C2, which was isolated from the encrusting pore coral Montipora aequituberculata from the Kenting coast of Southern Taiwan, was found to exhibit antibacterial activity against several meticillin-resistant S. aureus strains and to synthesize an antibacterial protein (Chen et al, 2010).…”

Myroides phaeus sp. nov., isolated from human saliva, and emended descriptions of the genus Myroides and the species Myroides profundi Zhang et al. 2009 and Myroides marinus Cho et al. 2011

“…Extraction and purification of total genomic DNA from the cells and PCR amplification of the 16S rRNA gene were performed as described by Jin et al (2010). The nearly complete 16S rRNA gene sequence (1356 nt) of strain MY15…”

Genome Sequence of Pseudoalteromonas flavipulchra JG1, a Marine Antagonistic Bacterium with Abundant Antimicrobial Metabolites

“…The marine antagonistic bacterium Pseudoalteromonas flavipulchra JG1, with a golden yellow color, was isolated from water used to rear healthy turbot (Scophthalmus maximus) in Qingdao, China (7). JG1 was confirmed to show excellent antibacterial activities against many fish pathogens and could synthesize a range of antibacterial compounds, including the protein PfaP and five small molecules (12).…”