Quorum sensing signal production by sponge-associated bacteria isolated from the Red Sea, Egypt

Abstract

Bacteria regulate their social activities and physiological processes through a quorum sensing (QS) mechanism. Many bacteria inhabit the mesohyl matrix of sponges. This symbiotic relationship is believed to contribute to the health and nutrition of sponges by production of protective antibiotics, the acquisition of limiting nutrients and nitrogen fixation. Marine isolates were analysed by bioassays using two different acylated homoserine lactone (AHL) reporter bacteria Chromobacterium violaceum 026 (CV026) and Agrobacterium tumefaciens KYC55. Thirty four marine isolates activated the A. tumefaciens and produce blue color. Using degenerate LuxS primers, partial LuxS gene sequences were detected in both Gram-negative and Gram-positive species including Bacillus species, Proteus species, uncultured Bacterium species, Micrococcus species and Bacterium NLAE-zl-H221. Using degenerate LuxR primers, partial LuxR gene sequences were detected in Proteus spp., Providencia species and Bacterium NLAE-zl-H221. Partial LuxS gene sequences were detected in both Gramnegative and Gram-positive. The results thus assure the fact that LuxS gene has been proposed to be a universal interspecies signaling molecule. This study showed that, Proteus mirabilis strain SZH18, Proteus vulgaris and Bacterium NLAE-zl-H221 have both luxS and luxR genes, thus it was claimed that these isolates have the potential to use two different QS systems, for intraspecies communication and communication with other species.

Detectable quorum signaling molecule via PANI-metal oxides nanocomposites sensors

“…This bacterial strain is responsible for the expression of a lacZ fusion in response to the C 6 -HSL. This leads to cleavage of 5-Bromo-4-chloro-3indolylgalactopyranoside (X-Gal) (Promega, Madison, WI, USA) and staining the agar plates with blue color as an indication for the C 6 -HSL and recorded as a positive result 58 . The C 6 -HSL production was assessed as (+ 1) for the positive medium production of the C 6 -HSL in comparison to the positive (+ ve) and negative (-ve) controls 58 .…”

“…This leads to cleavage of 5-Bromo-4-chloro-3indolylgalactopyranoside (X-Gal) (Promega, Madison, WI, USA) and staining the agar plates with blue color as an indication for the C 6 -HSL and recorded as a positive result 58 . The C 6 -HSL production was assessed as (+ 1) for the positive medium production of the C 6 -HSL in comparison to the positive (+ ve) and negative (-ve) controls 58 . Further information describing the procedure of the colorimetric detection of the C 6 -HSL using the biosensor colorimetric technique was demonstrated in the supplementary materials.…”

Chitosan–Aspirin Combination Inhibits Quorum-Sensing Synthases (lasI and rhlI) in Pseudomonas aeruginosa

“…tumefaciens KYC55 (pJZ372; pJZ384; pJZ410) was used as a biosensor for the AHLs. A. tumefaciens was cultured in AT limited salt medium supplemented with 100 g mL −1 spectinomycin, 100 g mL −1 gentamicin, and 4 g mL −1 tetracycline to preserve the required plasmids [17]. The antibiotics and chemicals were purchased from Sigma-Aldrich, Germany.…”

Quorum-Signaling Molecule Detection Based on Composite Sensors: Metal Oxides/Conducting Polymer

“…This bacterial strain is responsible for the expression of a lacZ fusion in response to the C 6 -HSL. This leads to cleavage of 5-Bromo-4-chloro-3indolylgalactopyranoside (X-Gal) (Promega, Madison, WI, USA) and staining the agar plates with blue color as an indication for the C 6 -HSL and recorded as a positive result [45]. The C 6 -HSL production was assessed as (+ 1) for the positive medium production of the C 6 -HSL in comparison to the positive (+ ve) and negative (-ve) controls [45].…”