Spoilage of refrigerated Litopenaeus vannamei: eavesdropping on Acinetobacter acyl-homoserine lactones promotes the spoilage potential of Shewanella baltica

Abstract

and are among the predominant spoilage bacteria in refrigerated shrimp (). are incapable of producing acyl-homoserine lactone (AHL) quorum sensing signals, but can respond to environmental AHLs. In this paper, was found to produce three AHLs, i.e. -butanoyl-l-homoserine lactone (C4-HSL),-(3-oxohexanoyl)-l-homoserine lactone (O-C6-HSL) and -(3-oxooctanoyl)-l-homoserine lactone (O-C8-HSL), according to thin-layer chromatography using the bioreporter A136. The agar diffusion and β-galactosidase assays revealed that could eavesdrop on these three AHLs from. Eavesdropping on AHLs especially C4-HSL was found to boost the growth of particularly under nutrient limiting conditions (up to 40-fold increase) in the co-culture experiments. The azocasein assay revealed that produced fourfold more extracellular proteases in response to AHLs. As demonstrated by the biofilm crystal violet staining assay and confocal laser scanning microscopy, eavesdropping also decreased the biofilm-forming capacity of . By inoculation of and onto surface-sterilized shrimp, eavesdropping was found to endow a growth advantage to in vivo, resulting in a 0.5 day shortened shelf life of shrimp according to total volatile basic nitrogen levels and sensory analysis. Overall, the AHL-dependent eavesdropping increased the spoilage potential of , providing a fresh perspective on the spoilage process of refrigerated, and this may inspire the development of novel preservation techniques in the future to further reduce post-harvest loss of shrimp.

Involvement of Exogenous N-Acyl-Homoserine Lactones in Spoilage Potential of Pseudomonas fluorescens Isolated From Refrigerated Turbot

“…While it is difficult to fully define the causes of this phenomenon, the results obtained here suggested that P. fluorescens have the ability of utilizing non-secreted AHLs to regulate their growth. These findings agreed with those of Zhu et al (2018), who showed that exogenous AHLs can be utilized by S. baltica through the LuxR receptor to promote growth.…”

“…Cultures without P. fluorescens showed no significant AHLs depletion. Similarly, the determination of β-galactosidase by Zhu et al (2018) revealed that S. baltica could eavesdrop on the ambient AHLs produced by Acinetobacter , and AHL activity of pure Acinetobacter culture was significantly higher than that of the co-culture of S. baltica and Acinetobacter with an inoculation ratio of 1:1. Notably, the content of C 4 -HSL in P. fluorescens cultures did not change dramatically after incubation compared to that of C 14 -HSL, although C 4 -HSL plays the most important role in biofilm and protease experiments.…”

Spoilage‐related microbiota in fish and crustaceans during storage: Research progress and future trends

“…Moreover, some studies (Huang et al., 2018; Jia, Liu, et al., 2018; Wang et al., 2014; Zhuang et al., 2019) characterized the microbiota composition before sensory rejection point and found out that some bacteria (e.g., Acinetobacter ) could be dominant before spoilage, although its predominance was finally occupied by SSOs. These bacteria are expected to promote the spoilage potential of SSOs by QS or metabiosis (Zhu et al., 2018), although their real roles in fish spoilage need further explorations. To conclude, sampling time in microbiota research largely depends on the aim of the study.…”

Isolation and identification of proteolytic, amylolytic, lipolytic, and chitinolytic bacteria from shrimp waste

“…anthropi, P. aeruginosa, V. alginolyticus, V. parahaemolyticus, B. velezensis and Shewanella spp. Shewanella genus have been described among the predominant spoilage bacteria in refrigerated shrimp (Litopenaeus vannamei) (Zhu et al 2018). Burkholderia cepacia has also been isolated from marine environments (Alkhunni et al 2017).…”