Abstract:Many bacteria biosynthesize structurally diverse exopolysaccharides (EPS) and excrete them into their surrounding environment. The EPS functional features have found many applications in industries such as cosmetics and pharmaceutics. In particular, some EPS produced by marine bacteria are composed of uronic acids, neutral sugars, and N-acetylhexosamines, and may also bear some functional sulfate groups. This suggests that they can share common structural features with glycosaminoglycans (GAG) like the two EPS… Show more
“…The EPS yield was higher in strain PQQ-42 (0.36 g l −1 ) than in strain PQQ-44 (0.15 g l −1 ), which confirmed the results observed by scanning electron microscopy. These EPS production values are similar to those obtained with other marine bacteria 42,43 .Figure 5Exopolysaccharide production in strains PQQ-42 and PQQ-44. Uranyl acetate staining of strains PQQ-42 ( a ) and PQQ-44 ( b ) as observed by transmission electron microscopy.…”
The Alteromonas stellipolaris strains PQQ-42 and PQQ-44, previously isolated from a fish hatchery, have been selected on the basis of their strong quorum quenching (QQ) activity, as well as their ability to reduce Vibrio-induced mortality on the coral Oculina patagonica. In this study, the genome sequences of both strains were determined and analyzed in order to identify the mechanism responsible for QQ activity. Both PQQ-42 and PQQ-44 were found to degrade a wide range of N-acylhomoserine lactone (AHL) QS signals, possibly due to the presence of an aac gene which encodes an AHL amidohydrolase. In addition, the different colony morphologies exhibited by the strains could be related to the differences observed in genes encoding cell wall biosynthesis and exopolysaccharide (EPS) production. The PQQ-42 strain produces more EPS (0.36 g l−1) than the PQQ-44 strain (0.15 g l−1), whose chemical compositions also differ. Remarkably, PQQ-44 EPS contains large amounts of fucose, a sugar used in high-value biotechnological applications. Furthermore, the genome of strain PQQ-42 contained a large non-ribosomal peptide synthase (NRPS) cluster with a previously unknown genetic structure. The synthesis of enzymes and other bioactive compounds were also identified, indicating that PQQ-42 and PQQ-44 could have biotechnological applications.
“…The EPS yield was higher in strain PQQ-42 (0.36 g l −1 ) than in strain PQQ-44 (0.15 g l −1 ), which confirmed the results observed by scanning electron microscopy. These EPS production values are similar to those obtained with other marine bacteria 42,43 .Figure 5Exopolysaccharide production in strains PQQ-42 and PQQ-44. Uranyl acetate staining of strains PQQ-42 ( a ) and PQQ-44 ( b ) as observed by transmission electron microscopy.…”
The Alteromonas stellipolaris strains PQQ-42 and PQQ-44, previously isolated from a fish hatchery, have been selected on the basis of their strong quorum quenching (QQ) activity, as well as their ability to reduce Vibrio-induced mortality on the coral Oculina patagonica. In this study, the genome sequences of both strains were determined and analyzed in order to identify the mechanism responsible for QQ activity. Both PQQ-42 and PQQ-44 were found to degrade a wide range of N-acylhomoserine lactone (AHL) QS signals, possibly due to the presence of an aac gene which encodes an AHL amidohydrolase. In addition, the different colony morphologies exhibited by the strains could be related to the differences observed in genes encoding cell wall biosynthesis and exopolysaccharide (EPS) production. The PQQ-42 strain produces more EPS (0.36 g l−1) than the PQQ-44 strain (0.15 g l−1), whose chemical compositions also differ. Remarkably, PQQ-44 EPS contains large amounts of fucose, a sugar used in high-value biotechnological applications. Furthermore, the genome of strain PQQ-42 contained a large non-ribosomal peptide synthase (NRPS) cluster with a previously unknown genetic structure. The synthesis of enzymes and other bioactive compounds were also identified, indicating that PQQ-42 and PQQ-44 could have biotechnological applications.
“…The marine environment and in particular extreme habitats, such as deep-sea hydrothermal vents constitute a potential resource of unknown bacteria that can synthesize EPS with unique structures (Delbarre-Ladrat, Sinquin, Lebellenger, Zykwinska, & Colliec-Jouault, 2014;Delbarre-Ladrat, Leyva Salas, Sinquin, Zykwinska, & Colliec-Jouault, 2017).…”
Polysaccharides have attracted much attention due to their interesting physico-chemical and also biological properties that are explored in food, cosmetic and pharmaceutical industries. GY785 exopolysaccharide (EPS) presenting an unusual structure is secreted by the deep-sea hydrothermal bacterium, Alteromonas infernus. Low-molecular weight (LMW) derivatives obtained by chemical depolymerization of the native high molecular weight (HMW) EPS were previously shown to exhibit biological properties similar to glycosaminoglycans (GAG). In the present study, in order to generate well defined derivatives with a better control of the depolymerization, an enzymatic approach was applied for the first time. Various commercially available enzymes were firstly screened for their depolymerizing activities, however none of them was able to degrade the polysaccharide. Enzymatic assays performed with A. infernus protein extracts have shown that the bacterium produces by itself endogenous enzymes able to depolymerize its own EPS. The oligosaccharides released by the enzymes were analyzed and their structures allowed to assess that the protein extract contains several depolymerizing activities.
“…Then, 200 µL of 10 mM Tris with 1mM EDTA (ethylenediaminetetraacetic acid) were added to the pellet; bacteria were lysed by heating at 95 • C for 10 min and cleared using centrifugation. The 16S rDNA gene was amplified directly from the supernatant (1 µL) using polymerase chain reaction (PCR) with 8F and 1489R primers as previously described [42]. PCR amplification was performed using a DreamTaq Green polymerase Master mix (Thermo Fisher Scientific, Illkirch, France).…”
Section: Identification Of the Ms969 Strainmentioning
In the marine environment, biofilm formation is an important lifestyle for microorganisms. A biofilm is comprised of cells embedded in an extracellular matrix that holds them close together and keeps the biofilm attached to the colonized surface. This predominant lifestyle and its main regulation pathway, namely quorum-sensing (QS), have been shown to induce specific bioactive metabolites. In this study, we investigated the biofilm formation by two marine bacteria belonging to the Vibrio species to discover potentially innovative bioactive compounds. We proposed a protocol to isolate biofilm extracts, to analyze their biochemical composition, and to compare them to planktonic cell extracts. Cells were grown attached to a plastic surface; extracts were prepared in water, NaOH, or in ethyl acetate and analyzed. Extracellular matrix components featured carbohydrates, proteins, lipids, and low amount of DNA. Carbohydrates appeared to be the main constituent of biofilm but also of the planktonic cell supernatant. Moreover, antimicrobial and QS-signaling activities were evidenced in extracts.
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