National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, 201306, Shanghai, People's Republic of China.
Published: March 2020
AI Article Synopsis
Article Abstract
Quorum sensing, bacterial cell-to-cell communication via small signaling molecules regulates virulence in many bacterial pathogens, and is a promising target for antivirulence therapy, which may inhibit virulence rather than cell growth and division. Herein, Bacillus strains capable of degrading QS molecules from freshwater environments were screened as potential aquaculture probiotics. A total of 34 Bacillus strains were isolated. Strain T-1 was selected with "H" streaking and double layer agar plate methods using Chromabacterium violaceum ATCC12472 as reporter, and eventually identified as Bacillus licheniformis based on biochemical and molecular identification. Quorum quenching by T-1 was confirmed using C. violaceum CV026. T-1 was non-hemolytic in vitro. In biocontrol experiments, T-1 reduced the pathogenicity of Aeromonas hydrophila cb15 in zebrafish co-injected intraperitoneally with both strains, achieving a relative percentage survival of 70%. Determination and analysis of the T-1 draft genome using the Illumina Hiseq 2500 platform identified the quorum quenching gene ytnP, encoding an acyl-homoserine lactone metallo-β-lactamase, as a potential QS quencher in T-1. In conclusion, B. licheniformis T-1 could be a safe and effective quorum quenching bacterium for protecting hosts against pathogenic bacterial infections in aquaculture.
The persistent increase in multidrug-resistant pathogens has catalyzed the creation of novel strategies to address antivirulence and anti-infective elements. Such methodologies aim to diminish the selective pressure exerted on bacterial populations, decreasing the likelihood of resistance emergence. This review explores the role of biofilm formation as a significant virulence factor and its impact on the development of antimicrobial resistance (AMR).
Nitrogen emissions up to the standard are a major challenge for wastewater treatment plants in alpine and high-altitude areas. The dosing of carriers can improve the nitrogen removal efficiency of the system at low temperatures; however, the mechanism of action of sludge and biofilm in nitrogen removal remains unclear. This study elucidated the internal mechanism of nitrogen removal via the function of microbial metabolism in sludge and biofilm at low temperatures.
Bacteria have developed a cell-to-cell communication system called quorum sensing (QS), allowing them to regulate group behavior and synchronize the expression of virulence factors, responsible for increasing their infection capacity and resistance to antimicrobials. Although the control of microbial infections through the inhibition of microbial growth has traditionally been the basis of antimicrobial chemotherapy, the emergence of antimicrobial resistance has led to the search for new microbial control strategies, namely through the inhibition of QS. Among the agents studied to inhibit this bacterial communication are essential oils (EO), which are considered very effective QS inhibitors.
Microcystin-LRs (MC-LR) produced by harmful cyanobacterial blooms (HCBs) pose significant hepatotoxic risks to both the environment and public health. Despite the identification and characterization of a limited number of MC-LR degrading bacteria, the challenge of safely removing MC-LRs from freshwater systems without disrupting aquatic ecosystems remains substantial. This study focused on the isolation of lactic acid bacteria from Bapshikhe, a traditional Korean fermented food, and investigated the mechanisms underlying the degradation of MC-LRs by these bacteria.
Unlabelled: is a Gram-negative opportunistic pathogen that poses a significant public health threat, particularly in healthcare settings. A key determinant of virulence is the regulated synthesis and release of extracellular products, which is controlled by a cell density-dependent signaling system known as quorum sensing (QS). uses a complex QS network, including two systems that rely on diffusible N-acylhomoserine lactone (AHL) signal molecules.
