Autoinducer-2-like Activity in Lactic Acid Bacteria Isolated from Minced Beef Packaged under Modified Atmospheres

Abstract

Fifteen fingerprints (assigned to Leuconostoc spp., Leuconostoc mesenteroides, Weissella viridescens, Leuconostoc citreum, and Lactobacillus sakei) of 89 lactic acid bacteria (LAB) isolated from minced beef stored under modified atmospheres at various temperatures were screened for their ability to exhibit autoinducer-2 (AI-2)-like activity under certain growth conditions. Cellfree meat extracts (CFME) were collected at the same time as the LAB isolates and tested for the presence of AI-2-like molecules. All bioassays were conducted using the Vibrio harveyi BAA-1117 (sensor 1(-), sensor 2(+)) biosensor strain. The possible inhibitory effect of meat extracts on the activity of the biosensor strain was also evaluated. AI-2-like activity was observed for Leuconostoc spp. isolates, but none of the L. sakei strains produced detectable AI-2-like activity. The AI-2-like activity was evident mainly associated with the Leuconostoc sp. B 233 strain, which was the dominant isolate recovered from storage at 10 and 15°C and at the initial and middle stages of storage at chill temperatures (0 and 5°C). The tested CFME samples displayed low AI-2-like activity and inhibited AI-2 activity regardless of the indigenous bacterial populations. The LAB isolated during meat spoilage exhibited AI-2-like activity, whereas the LAB strains retrieved depended on storage time and temperature. The production of AI-2-like molecules may affect the dominance of different bacterial strains during storage. The results provide a basis for further research concerning the effect of storage temperature on the expression of genes encoding AI-2 activity and on the diversity of the ephemeral bacterial population.

Ιn Vitro Screening of γ-Aminobutyric Acid and Autoinducer-2 Signalling in Lactic Acid Bacteria Exhibiting Probiotic Potential Isolated from Natural Black Conservolea Olives

“…For this assay, two strains of Vibrio harveyi were used: V. harveyi BAA-1117 (ATCC BB-170) as biosensor and V. harveyi BAA-1119 (ATCC BB152) as positive control. Vibrio strains were cultured in Autoinducer Bioassay (AB) broth [35], and incubated with agitation (160 rpm) at 30 • C for 24 h. The cultures used directly in the bioassay were prepared by transferring a single colony from AB agar in 10 mL of AB broth, and incubating with agitation (160 rpm) at 30 • C for 16 h. For the growth of the LAB strains, quarter-strength brain heart infusion (BHI) broth (Lab M Limited, Lancashire, United Kingdom) was used as previously reported [36]. The AI-2 activity bioassay was performed as described previously [37].…”

“…According to the results obtained, the selected strains exhibiting probiotic potential did not show detectable AI-2 activity under these growth conditions. Generally, diverse results have been reported with regard to the ability of LAB to produce AI-2 molecules [24,36,51]. The detection of AI-2 molecules has been proven to be growth-medium dependent [52,53].…”

Assessment of the effect of a Salmonella enterica ser. Typhimurium culture supernatant on the single-cell lag time of foodborne pathogens

“…Despite the fact that the presence of QS signal molecules in food systems has been demonstrated (Blana and Nychas, 2014;Blana et al, 2011;Nychas et al, 2009), their exact role has not been completely exemplified. The majority of studies on cell-to-cell communication have focused on assessing the molecular aspects and the genetic processes underlying this phenomenon (Surette and Bassler, 1998;Taga et al, 2003), with relatively limited attention being paid to how both intraand inter-species communication modulate bacterial growth responses.…”

In vitro probiotic attributes of lactic acid bacteria and their spoilage potential in meat products

“…The selected strains from the previous tests were further evaluated regarding their potential haemolytic activity and antimicrobial activity according to Argyri et al (2013) (Blana, Doulgeraki and Nychas, 2011). The AI-2 activity bioassay was performed as described previously (Surette and Bassler, 1998).…”

“…According to the results obtained, the selected strains exhibiting probiotic potential did not show detectable AI-2 activity under these growth conditions. Generally, diverse results have been reported with regard to the ability of LAB to produce AI-2 molecules (Moslehi-Jenabian, Gori and Jespersen, 2009;Blana, Doulgeraki and Nychas, 2011;Park et al 2016). The detection of AI-2 molecules has been proven to be growth-medium dependent (Surette and Bassler, 1999;De Keersmaecker and Vanderleyden, 2003).…”