Characterization of Quorum Sensing Signals in Coral-Associated Bacteria

2011 ◽  
Vol 61 (4) ◽  
pp. 783-792 ◽  
Author(s):  
Karina Golberg ◽  
Evgeni Eltzov ◽  
Maya Shnit-Orland ◽  
Robert S. Marks ◽  
Ariel Kushmaro
2010 ◽  
Vol 77 (4) ◽  
pp. 1181-1186 ◽  
Author(s):  
Filomena S. W. Ng ◽  
Daniel M. Wright ◽  
Stephen Y. K. Seah

ABSTRACTSsoPox, a bifunctional enzyme with organophosphate hydrolase andN-acyl homoserine lactonase activities from the hyperthermophilic archaeonSulfolobus solfataricus, was overexpressed and purified from recombinantPseudomonas putidaKT2440 with a yield of 9.4 mg of protein per liter of culture. The enzyme has a preference forN-acyl homoserine lactones (AHLs) with acyl chain lengths of at least 8 carbon atoms, mainly due to lowerKmvalues for these substrates. The highest specificity constant obtained was forN-3-oxo-decanoyl homoserine lactone (kcat/Km= 5.5 × 103M−1·s−1), but SsoPox can also degradeN-butyryl homoserine lactone (C4-HSL) andN-oxo-dodecanoyl homoserine lactone (oxo-C12-HSL), which are important for quorum sensing in ourPseudomonas aeruginosamodel system. WhenP. aeruginosaPAO1 cultures were grown in the presence of SsoPox-immobilized membranes, the production of C4-HSL- and oxo-C12-HSL-regulated virulence factors, elastase, protease, and pyocyanin were significantly reduced. This is the first demonstration that immobilized quorum-quenching enzymes can be used to attenuate the production of virulence factors controlled by quorum-sensing signals.


2014 ◽  
Vol 9 (2) ◽  
pp. 1934578X1400900
Author(s):  
Gennaro Roberto Abbamondi ◽  
Salvatore De Rosa ◽  
Carmine Iodice ◽  
Giuseppina Tommonaro

Four bacterial strains belonging to the genera Vibrio, Pseudoalteromonas and Photobacterium were isolated from the marine sponges Dysidea avara and Geodia cynodium. A Bacillus strain was isolated from Ircinia variabilis. A screening of molecules involved in quorum sensing (QS) was carried out by TLC-overlay and a new “plate T-streak” test. To analyze quorum quenching (QQ), a plate T-streak was performed with Chromobacterium violaceum. Strains of Vibrio isolated from both marine sponges and a strain of Photobacterium isolated from G. cynodium, activated QS bioreporters. A strain of Pseudoalteromonas isolated from D. avara showed QQ activity. Finally, it is reported that cyclic dipeptides isolated from strains of Vibrio sp. and Bacillus sp. (isolated from D. avara and I. variabilis, respectively) were involved in the QS mechanism. The simultaneous presence of bacteria that showed contrasting responses in bioassays for QS signal molecule synthesis in marine sponges could add an interesting dimension to the signalling interactions which may be happening in sponges.


2013 ◽  
Vol 164 (7) ◽  
pp. 749-760 ◽  
Author(s):  
Francisco Pérez-Montaño ◽  
Irene Jiménez-Guerrero ◽  
Rocío Contreras Sánchez-Matamoros ◽  
Francisco Javier López-Baena ◽  
Francisco Javier Ollero ◽  
...  

Author(s):  
Alberto Ruiz ◽  
Marta Herráez ◽  
Stefanie B. Costa‐Gutierrez ◽  
María Antonia Molina‐Henares ◽  
María Jesús Martínez ◽  
...  

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Rashid Pervez ◽  
Showkat Ahmad Lone ◽  
Sasmita Pattnaik

Abstract Background Entomopathogenic nematodes (EPNs) harboring symbiotic bacteria are one of the safest alternatives to the chemical insecticides for the control of various insect pests. Infective juveniles of EPNs locate a target insect, enter through the openings, and reach the hemocoel, where they release the symbiotic bacteria and the target gets killed by the virulence factors of the bacteria. Photorhabdus with Heterorhabditis spp. are well documented; little is known about the associated bacteria. Main body In this study, we explored the presence of symbiotic and associated bacteria from Heterorhabditis sp. (IISR-EPN 09) and characterized by phenotypic, biochemical, and molecular approaches. Six bacterial isolates, belonging to four different genera, were recovered and identified as follows: Photorhabdus luminescens, one each strain of Providencia vermicola, Pseudomonas entomophila, Alcaligenes aquatilis, and two strains of Alcaligenes faecalis based on the phenotypic, biochemical criteria and the sequencing of 16S rRNA gene. Conclusion P. luminescens is symbiotically associated with Heterorhabditis sp. (IISR-EPN 09), whereas P. vermicola, P. entomophila, A. aquatilis, and A. faecalis are the associated bacteria. Further studies are needed to determine the exact role of the bacterial associates with the Heterorhabditis sp.


2021 ◽  
Vol 9 (7) ◽  
pp. 1496
Author(s):  
Rubiyatno ◽  
Kazuhiro Mori ◽  
Daisuke Inoue ◽  
Sunah Kim ◽  
Jaecheul Yu ◽  
...  

Euglena gracilis produces paramylon, which is a feedstock for high-value functional foods and nutritional supplements. The enhancement of paramylon productivity is a critical challenge. Microalgae growth-promoting bacteria (MGPB) can improve microalgal productivity; however, the MGPB for E. gracilis remain unclear. This study isolated bacteria capable of enhancing E. gracilis growth and paramylon production under mixotrophic conditions. Enterobacter sp. CA3 and Emticicia sp. CN5 were isolated from E. gracilis grown with sewage-effluent bacteria under mixotrophic conditions at pH 4.5 or 7.5, respectively. In a 7-day E. gracilis mixotrophic culture with glucose, CA3 increased E. gracilis biomass and paramylon production 1.8-fold and 3.5-fold, respectively (at pH 4.5), or 1.9-fold and 3.5-fold, respectively (at pH 7.5). CN5 increased E. gracilis biomass and paramylon production 2.0-fold and 4.1-fold, respectively (at pH 7.5). However, the strains did not show such effects on E. gracilis under autotrophic conditions without glucose. The results suggest that CA3 and CN5 promoted both E. gracilis growth and paramylon production under mixotrophic conditions with glucose at pH 4.5 and 7.5 (CA3) or pH 7.5 (CN5). This study also provides an isolation method for E. gracilis MGPB that enables the construction of an effective E. gracilis–MGPB-association system for increasing the paramylon yield of E. gracilis.


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