A novel genomic island encodes vibrioferrin synthesis in the marine pathogen Photobacterium damselae subsp. damselae.

In this study, we identified and analyzed a novel genomic island (GI), named pddGI-1, located on chromosome II of certain strains of the marine pathogen Photobacterium damselae subsp. damselae (Pdd). This GI shares structural similarities with other GIs found in Vibrio species, such as the Vibrio seventh pandemic island-II (VSP-II) of V.

Outer membrane vesicles (OMVs) from Tenacibaculum maritimum as a potential vaccine against fish tenacibaculosis.

Outer membrane vesicles (OMVs) have been gained increasing attention in vaccinology due to their ability to induce strong protective humoral and cell-mediated immunity. The Gram-negative bacterium Tenacibaculum maritimum, the causative agent of marine tenacibaculosis, poses a significant challenge to the global aquaculture industry due to its difficult prophylaxis. In previous studies, we demonstrated that OMV production is a key virulence mechanism in T.

O-versus S-Metal Coordination of the Thiocarboxylate Group: An NMR Study of the Two Tautomeric Forms of the Ga(III)-Photoxenobactin E Complex.

Photoxenobactin E () is a natural product with an unusual thiocarboxylic acid terminus recently isolated from an entomopathogenic bacterium. The biosynthetic gene cluster associated with photoxenobactin E, and other reported derivatives, is very similar to that of piscibactin, the siderophore responsible for the iron uptake among bacteria of the family, including potential human pathogens. Here, the reisolation of from the fish pathogen RV22 cultured under iron deprivation, its ability to chelate Ga(III), and the full NMR spectroscopic characterization of the Ga(III)-photoxenobactin E complex are presented.

Remodulation of bacterial transcriptome after acquisition of foreign DNA: the case of -HPI high-pathogenicity island in .

The high-pathogenicity island -HPI is widespread in and encodes the siderophore piscibactin, as well as the regulator PbtA that is essential for its expression. In this work, we aim to study whether PbtA directly interacts with -HPI promoters. Furthermore, we hypothesize that PbtA, and thereby the acquisition of -HPI island, may also influence the expression of other genes elsewhere in the bacterial genome.

The secretome of the fish pathogen includes soluble virulence-related proteins and outer membrane vesicles.

, the etiological agent of tenacibaculosis in marine fish, constitutively secretes extracellular products (ECPs) in which protein content has not been yet comprehensively studied. In this work, the prevalence of extracellular proteolytic and lipolytic activities related to virulence was analyzed in 64 strains belonging to the O1-O4 serotypes. The results showed the existence of a great intra-specific heterogeneity in the enzymatic capacity, particularly within serotype O4.

The Sigma Factor AsbI Is Required for the Expression of Acinetobactin Siderophore Transport Genes in .

subsp. (), a Gram-negative bacterium causing furunculosis in fish, produces the siderophores acinetobactin and amonabactins in order to extract iron from its hosts. While the synthesis and transport of both systems is well understood, the regulation pathways and conditions necessary for the production of each one of these siderophores are not clear.

Structural Requirements for Ga Coordination in Synthetic Analogues of the Siderophore Piscibactin Deduced by Chemical Synthesis and Density Functional Theory Calculations.

Stereoselective total synthesis of several analogues of piscibactin (Pcb), the siderophore produced by different pathogenic Gram-negative bacteria, was performed. The acid-sensitive αmethylthiazoline moiety was replaced by a more stable thiazole ring, differing in the configuration of the OH group at the C-13 position. The ability of these Pcb analogues to form complexes with Ga as a mimic of Fe showed that the configuration of the hydroxyl group at C-13 as 13 is crucial for the chelation of Ga to preserve the metal coordination, while the presence of a thiazole ring instead of the αmethylthiazoline moiety does not affect such coordination.

Identification of Key Functions Required for Production and Utilization of the Siderophore Piscibactin Encoded by the High-Pathogenicity Island -HPI in .

Piscibactin is a widespread siderophore system present in many different bacteria, especially within the family. Previous works showed that most functions required for biosynthesis and transport of this siderophore are encoded by the high-pathogenicity island -HPI. In the present work, using as a model, we could identify additional key functions encoded by -HPI that are necessary for piscibactin production and transport and that have remained unknown.

Selective detection of Aeromonas spp. by a fluorescent probe based on the siderophore amonabactin.

Amonabactins, the siderophores produced by some pathogenic bacteria belonging to Aeromonas genus, can be used for the preparation of conjugates to be imported into the cell using their specific transport machinery. Herein, we report the design and synthesis of a new amonabactin-based fluorescent probe by conjugation of the appropriate amonabactin analogue to sulforhodamine B (AMB-SRB) using a thiol-maleimide click reaction. Growth promotion assays and fluorescence microscopy studies demonstrated that the AMB-SRB fluorescent probe was able to label the fish pathogenic bacterium A.

The Temperature-Dependent Expression of the High-Pathogenicity Island Encoding Piscibactin in Results From the Combined Effect of the AraC-Like Transcriptional Activator PbtA and Regulatory Factors From the Recipient Genome.

The high-pathogenicity island -HPI is widespread among encoding the piscibactin siderophore system. The expression of piscibactin genes in the fish pathogen is favored by low temperatures. However, information about the regulatory mechanism behind -HPI gene expression is scarce.

Susceptibility to Bismuth(III) of Aquaculture Bacterial Pathogens: Effectiveness of Bismuth-Deferiprone Therapy against Infection in Fish.

Bismuth is a heavy metal with antibacterial properties that has a long history of medicinal use. The results reported here suggest that bismuth(III) (chelated with deferiprone) could be used in aquaculture systems to treat bacterial disease outbreaks, greatly reducing antibiotic use. We tested bismuth susceptibility in a collection of aquaculture bacterial pathogens.

FrpA is the outer membrane piscibactin transporter in Vibrio anguillarum: structural elements in synthetic piscibactin analogues required for transport.

Piscibactin (Pcb) is a labile siderophore widespread among Vibrionaceae. Its production is a major virulence factor of some fish pathogens such as Photobacterium damselae subsp. piscicida and Vibrio anguillarum.

Produces Piscibactin and Amphibactin and Both Siderophores Contribute Significantly to Virulence for Clams.

is an inhabitant of mollusc microbiota and an opportunistic pathogen causing disease outbreaks in marine bivalve mollusc species including oysters and clams. Virulence of mollusc pathogenic vibrios is mainly associated with the production of extracellular products. However, siderophore production is a common feature in pathogenic marine bacteria but its role in fitness and virulence of mollusc pathogens remains unknown.

Draft Genome Sequences of Five Vibrio neptunius Strains Isolated from Hatcheries of Bivalve Mollusks.

is a Gram-negative bacterium that has been shown to cause disease in marine bivalve mollusk larvae. Here, we report the draft genome sequences and annotations of five strains isolated from larvae of European oyster () and Manila clam () at hatcheries in Galicia, northwest Spain.

The Vibriolysin-Like Protease VnpA and the Collagenase ColA Are Required for Full Virulence of the Bivalve Mollusks Pathogen .

is an important pathogen of bivalve mollusks worldwide. Several metalloproteases have been described as virulence factors in species of that are pathogenic to bivalves, but little is known about the contribution of these potential virulence factors to pathogenesis. In silico analysis of the genome of strain PP-145.

The marine bivalve molluscs pathogen Vibrio neptunius produces the siderophore amphibactin, which is widespread in molluscs microbiota.

Amphiphilic siderophores, including amphibactins, are the most abundant siderophores in oceans. Genes putatively encoding the amphibactin system were proposed in some bacteria and homologues of these genes are particularly abundant in multiple bacterial lineages inhabitant of low-iron seawater. However, since no defective mutant strains in any of these genes were studied to date, their role in amphibactin synthesis or uptake was not demonstrated.

Synthesis of Functionalized Magnetic Nanoparticles, Their Conjugation with the Siderophore Feroxamine and its Evaluation for Bacteria Detection.

In the present work, the synthesis of magnetic nanoparticles, its coating with SiO2, followed by its amine functionalization with (3-aminopropyl)triethoxysilane (APTES) and its conjugation with deferoxamine, a siderophore recognized by Yersinia enterocolitica, using a succinyl moiety as a linker are described. Magnetic nanoparticles (MNP) of magnetite (Fe3O4) were prepared by solvothermal method and coated with SiO2 (MNP@SiO2) using the Stöber process followed by functionalization with APTES (MNP@SiO2@NH2). Then, feroxamine was conjugated with the MNP@SiO2@NH2 by carbodiimide coupling to give MNP@SiO2@NH2@Fa.

The Expression of Virulence Factors in Is Dually Regulated by Iron Levels and Temperature.

causes a hemorrhagic septicemia that affects cold- and warm-water adapted fish species. The main goal of this work was to determine the temperature-dependent changes in the virulence factors that could explain the virulence properties of for fish cultivated at different temperatures. We have found that although the optimal growth temperature is around 25°C, the degree of virulence of RV22 is higher at 15°C.

Outer membrane protein FrpA, the siderophore piscibactin receptor of Photobacterium damselae subsp. piscicida, as a subunit vaccine against photobacteriosis in sole (Solea senegalensis).

Photobacteriosis caused by Photobacterium damselae subsp. piscicida (Pdp) remains one of the main infectious diseases affecting cultured fish in Mediterranean countries. Diverse vaccine formulations based in the use of inactivated bacterial cells have been used with unsatisfactory results, especially in newly cultured species like sole (Solea senegalensis).

The Outer Membrane Protein FstC of subsp. Acts as Receptor for Amonabactin Siderophores and Displays a Wide Ligand Plasticity. Structure-Activity Relationships of Synthetic Amonabactin Analogues.

Amonabactins are a group of four related catecholate siderophores produced by several species of the genus , including and the fish pathogen subsp. Although the gene cluster encoding amonabactin biosynthesis also contains a gene that could encode the ferri-siderophore receptor (), to date there is no experimental evidence to explain its role. In this work, we report the identification of the amonabactins' outer membrane receptor and the determination of the minimal structural parts of these siderophores involved in the molecular recognition by their cognate receptor.

The Fish Pathogen Under Iron Deprivation Produces the Siderophore Piscibactin.

is the causative agent of vibriosis, mainly in salmonid fishes, and its virulence mechanisms are still not completely understood. In previous works we demonstrated that possess several iron uptake mechanisms based on heme utilization and siderophore production. The aim of the present work was to confirm the production and utilization of piscibactin as a siderophore by .

Preparation of functionalized magnetic nanoparticles conjugated with feroxamine and their evaluation for pathogen detection.

This work reports the preparation of a conjugate between amino-functionalized silica magnetite and the siderophore feroxamine. The morphology and properties of the conjugate and intermediate magnetic nanoparticles (MNPs) were examined by powder X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), magnetization studies, zeta potential measurements, Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) mapping. Furthermore, this study investigated the interaction between the functionalized magnetic NPs and wild type (WC-A) using Scanning Electron Microscopy (SEM) and TEM images.

The Siderophore Piscibactin Is a Relevant Virulence Factor for Favored at Low Temperatures.

causes vibriosis, a hemorrhagic septicaemia that affects many cultured marine fish species worldwide. Two catechol siderophores, vanchrobactin and anguibactin, were previously identified in this bacterium. While vanchrobactin is a chromosomally encoded system widespread in all pathogenic and environmental strains, anguibactin is a plasmid-encoded system restricted to serotype O1 strains.

Methodological evaluation of DNA-based molecular keys to identify categories of mislabelling in commercial products from genus Merluccius spp.

The large variety of fish formats which are globally commercialized supports use of meta-evaluation studies to test discrimination power among molecular keys available for traceability of highly-degraded and/or chemically-modified DNA material. This paper shows that a combination of DNA identification methods validated for genus Merluccius allows 100% species assignment in hake products and offers higher diagnostic power (97% on products) than individual methods, i.e.

Secreted Citrate Serves as Iron Carrier for the Marine Pathogen subsp .

subsp () is a that has a wide pathogenic potential against many marine animals and also against humans. Some strains of this bacterium acquire iron through the siderophore vibrioferrin. However, there are virulent strains that do not produce vibrioferrin, but they still give a strong positive reaction in the CAS test for siderophore production.