N-acyl homoserine lactone-degrading microbial enrichment cultures isolated from Penaeus vannamei shrimp gut and their probiotic properties in Brachionus plicatilis cultures

Abstract

Three bacterial enrichment cultures (ECs) were isolated from the digestive tract of Pacific white shrimp Penaeus vannamei, by growing the shrimp microbial communities in a mixture of N-acyl homoserine lactone (AHL) molecules. The ECs, characterized by denaturing gradient gel electrophoresis analysis and subsequent rRNA sequencing, degraded AHL molecules in the degradation assays. Apparently, the resting cells of the ECs also degraded one of the three types of quorum-sensing signal molecules produced by Vibrio harveyi in vitro [i.e. harveyi autoinducer 1 (HAI-1)]. The most efficient AHL-degrading ECs, EC5, was tested in Brachionus experiments. EC5 degraded the V. harveyi HAI-1 autoinducer in vivo, neutralizing the negative effect of V. harveyi autoinducer 2 (AI-2) mutant, in which only the HAI-1-and CAI-1-mediated components of the quorum-sensing system are functional on the growth of Brachionus. This suggests that EC5 interferes with HAI-1-regulated metabolism in V. harveyi. These AHL-degrading ECs need to be tested in other aquatic systems for their probiotic properties, preferably in combination with specific AI-2-degrading bacteria.

Exploiting Quorum Sensing To Confuse Bacterial Pathogens

“…EC5 was able to enhance growth of B. plicatilis challenged with V. harveyi mutants lacking functional AI-2 signaling but not those lacking only AHL QS. This indicated that EC5 was capable of degrading 3OHC4HSL and alleviating AHL-mediated growth defects but was unable to inhibit AI-2, and it suggested that probiotic treatment combining AHL-degrading ECs with AI-2-inhibitory bacteria or compounds may be an effective way to protect B. plicatilis during aquaculture (363). More recently, Nhan et al tested ECs from two types of sea bass for their abilities to improve the health of shrimp larvae exposed to waters contaminated with V. harveyi (364).…”

Degradation of N-Acylhomoserine Lactone Quorum Sensing Signaling Molecules by Potato Root Surface-Associated Chryseobacterium Strains

“…carotovorum (6). AHL-producing and -degrading bacteria coexist in various ecosystems, for example, Penaeus vannamei in shrimp gut and the intestine of Japanese ayu fish (12,25). These bacteria might have different strategies to gain competitive advantages.…”

Quorum sensing and quorum quenching in Vibrio harveyi: lessons learned from in vivo work

“…Enzymes that are able to inactivate AHLs have been discovered in different Gram-negative species belonging to the a-proteobacteria , the b-proteobacteria (Leadbetter and Greenberg, 2000;Lin et al, 2003;Uroz et al, 2003) and the gproteobacteria (Uroz et al, 2003) as well as in some Gram-positive species (Dong et al, 2002;Lee et al, 2002;Uroz et al, 2003). Interestingly, Tinh et al (2007a) very recently isolated AHL-degrading enrichment cultures from the digestive tract of healthy Pacific white shrimp (Penaeus vannamei). The enrichment cultures protected rotifers from the negative effects of an AI-2 non-producing V. harveyi mutant, suggesting that the bacteria interfered with HAI-1-regulated gene expression in vivo.…”