Structural Diversity among Core Oligosaccharides.

The genus presents five different pathogenic species: , , , and . These species cause infections mainly in fish, but they can also infect reptiles, birds or humans. Lipopolysaccharide (endotoxin) plays an important role in the pathogenesis of these bacteria.

Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility.

The study of glycosylation in prokaryotes is a rapidly growing area. Bacteria harbor different glycosylated structures on their surface whose glycans constitute a strain-specific barcode. The associated glycans show higher diversity in sugar composition and structure than those of eukaryotes and are important in bacterial-host recognition processes and interaction with the environment.

Complete Characterization of the O-Antigen from the LPS of .

species are found in the aquatic environment, drinking water, bottled mineral water, and different types of foods, such as meat, fish, seafood, or vegetables. Some of these species are primary or opportunistic pathogens for invertebrates and vertebrates, including humans. Among the pathogenic factors associated with these species, there are the lipopolysaccharides (LPSs).

Polar Flagella Glycosylation in : Genomic Characterization and Involvement of a Specific Glycosyltransferase (Fgi-1) in Heterogeneous Flagella Glycosylation.

Polar flagella from mesophilic strains have previously been shown to be modified with a range of glycans. Mass spectrometry studies of purified polar flagellins suggested the glycan typically includes a putative pseudaminic acid like derivative; while some strains are modified with this single monosaccharide, others modified with a heterologous glycan. In the current study, we demonstrate that genes involved in polar flagella glycosylation are clustered in highly polymorphic genomic islands flanked by pseudaminic acid biosynthetic genes ().

Nanoliposomes encapsulating immunostimulants modulate the innate immune system and elicit protection in zebrafish larvae.

Here we present immunostimulant-loaded nanoliposomes (NL) as a strategy to protect zebrafish larvae against bacterial infection. The NL encapsulate crude lipopolysaccharide (LPS) from E. coli and polyinosinic:polycytidylic acid (Poly I:C), a synthetic analogue of viral dsRNA.

Characterizing bacterial glycoproteins with LC-MS.

Though eukaryotic glycoproteins have been studied since their discovery in the 1930s, the first bacterial glycoprotein was not identified until the 1970s. As a result, their role in bacterial pathogenesis is still not well understood and they remain an understudied component of bacterial virulence. In recent years, mass spectrometry has emerged as a leading technology for the study of bacterial glycoproteins, largely due to its sensitivity and versatility.

The Complete Structure of the Core Oligosaccharide from Edwardsiella tarda EIB 202 Lipopolysaccharide.

The chemical structure and genomics of the lipopolysaccharide (LPS) core oligosaccharide of pathogenic strain EIB 202 were studied for the first time. The complete gene assignment for all LPS core biosynthesis gene functions was acquired. The complete structure of core oligosaccharide was investigated by ¹H and C nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry MS, and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry.

Structural Characterization of Core Region in Erwinia amylovora Lipopolysaccharide.

() is the first bacterial plant pathogen described and demonstrated to cause fire blight, a devastating plant disease affecting a wide range of species including a wide variety of . In this study, we reported the lipopolysaccharide (LPS) core structure from strain CFBP1430, the first one for an highly pathogenic strain. The chemical characterization was performed on the mutants (lacking only the O-antigen LPS with a complete LPS-core), and (outer-LPS core mutants).

Comparative Genomics of the Aeromonadaceae Core Oligosaccharide Biosynthetic Regions.

Lipopolysaccharides (LPSs) are an integral part of the Gram-negative outer membrane, playing important organizational and structural roles and taking part in the bacterial infection process. In , , and , three different genomic regions taking part in the LPS core oligosaccharide (Core-OS) assembly have been identified, although the characterization of these clusters in most aeromonad species is still lacking. Here, we analyse the conservation of these LPS biosynthesis gene clusters in the all the 170 currently public genomes, including 30 different species, and characterise the structure of a putative common inner Core-OS in the family.

The Animal Model Determines the Results of Virulence Factors.

The selection of an experimental animal model is of great importance in the study of bacterial virulence factors. Here, a bath infection of zebrafish larvae is proposed as an alternative model to study the virulence factors of . Intraperitoneal infections in mice and trout were compared with bath infections in zebrafish larvae using specific mutants.

Whole-Genome Sequence of Aeromonas hydrophila Strain AH-1 (Serotype O11).

Aeromonas hydrophila is an emerging pathogen of aquatic and terrestrial animals, including humans. Here, we report the whole-genome sequence of the septicemic A. hydrophila AH-1 strain, belonging to the serotype O11, and the first mesophilic Aeromonas with surface layer (S-layer) to be sequenced.

Genome Sequence of Aeromonas hydrophila Strain AH-3 (Serotype O34).

Aeromonas hydrophila is an emerging pathogen of poikilothermic animals, from fish to mammals, including humans. Here, we report the whole-genome sequence of the A. hydrophila AH-3 strain, isolated from a fish farm goldfish septicemia outbreak in Spain, with a characterized polar and lateral flagellum glycosylation pattern.

The FlgT Protein Is Involved in Aeromonas hydrophila Polar Flagella Stability and Not Affects Anchorage of Lateral Flagella.

Aeromonas hydrophila sodium-driven polar flagellum has a complex stator-motor. Consist of two sets of redundant and non-exchangeable proteins (PomA/PomB and PomA2/PomB2), which are homologs to other sodium-conducting polar flagellum stator motors; and also two essential proteins (MotX and MotY), that they interact with one of those two redundant pairs of proteins and form the T-ring. In this work, we described an essential protein for polar flagellum stability and rotation which is orthologs to Vibrio spp.

The first sugar of the repeat units is essential for the Wzy polymerase activity and elongation of the O-antigen lipopolysaccharide.

In the Wzx/Wzy-dependent assembled pathway, the assembled O-antigen repeat units are translocated from the cytosolic to the periplasmic face of the inner membrane by a Wzx translocase and then polymerized by the integral membrane protein Wzy to form a glycan chain. We demonstrate that the activity of the Escherichia coli O-antigen polymerase (Wzy) is dependent on the first sugar of the O-antigen repeat unit to produce the O-antigen polymerization and therefore, there is a need for a concerted action with the enzyme transferring the initial HexNAc to undecaprenyl phosphate (UDP-HexNAc: polyprenol-P HexNAc-1-P transferase). Furthermore, in the case of Aeromonas hydrophila Wzy-O34 polymerization activity, the enzyme is permissive with the sugar at the nonreducing end of the O-antigen repeat unit.

The Aeromonas salmonicida Lipopolysaccharide Core from Different Subspecies: The Unusual subsp. pectinolytica.

Initial hydridization tests using Aeromonas salmonicida typical and atypical strains showed the possibility of different lipopolysaccharide (LPS) outer cores among these strains. By chemical structural analysis, LPS-core SDS-PAGE gel migration, and functional and comparative genomics we demonstrated that typical A. salmonicida (subsp.

Polar Glycosylated and Lateral Non-Glycosylated Flagella from Aeromonas hydrophila Strain AH-1 (Serotype O11).

Polar and but not lateral flagellin proteins from Aeromonas hydrophila strain AH-1 (serotype O11) were found to be glycosylated. Top-down mass spectrometry studies of purified polar flagellins suggested the presence of a 403 Da glycan of mass. Bottom-up mass spectrometry studies showed the polar flagellin peptides to be modified with 403 Da glycans in O-linkage.

The polar and lateral flagella from Plesiomonas shigelloides are glycosylated with legionaminic acid.

Plesiomonas shigelloides is the unique member of the Enterobacteriaceae family able to produce polar flagella when grow in liquid medium and lateral flagella when grown in solid or semisolid media. In this study on P. shigelloides 302-73 strain, we found two different gene clusters, one exclusively for the lateral flagella biosynthesis and the other one containing the biosynthetic polar flagella genes with additional putative glycosylation genes.

The Polymerization of Aeromonas hydrophila AH-3 O-Antigen LPS: Concerted Action of WecP and Wzy.

The repeat units of heteropolymeric O antigen are synthesized at the cytosolic side of the inner bacterial membrane via the Wzx/Wzy-dependent assembly pathway. After being translocated across the membrane by Wzx, each repeat unit is polymerized by Wzy to form a glycan chain. In this study, we demonstrate the need of the corresponding enzyme transferring the initial HexNAc to undecaprenol phosphate (lipid carrier), together with the corresponding O-antigen polymerase (Wzy), to produce the Aeromonas hydrophila O:34-antigen.

Functional Genomics of the Aeromonas salmonicida Lipopolysaccharide O-Antigen and A-Layer from Typical and Atypical Strains.

The A. salmonicida A450 LPS O-antigen, encoded by the wbsalmo gene cluster, is exported through an ABC-2 transporter-dependent pathway. It represents the first example of an O-antigen LPS polysaccharide with three different monosaccharides in their repeating unit assembled by this pathway.

Virulence Factors of Erwinia amylovora: A Review.

Erwinia amylovora, a Gram negative bacteria of the Enterobacteriaceae family, is the causal agent of fire blight, a devastating plant disease affecting a wide range of host species within Rosaceae and a major global threat to commercial apple and pear production. Among the limited number of control options currently available, prophylactic application of antibiotics during the bloom period appears the most effective. Pathogen cells enter plants through the nectarthodes of flowers and other natural openings, such as wounds, and are capable of rapid movement within plants and the establishment of systemic infections.

Functional Genomic Screen Identifies Klebsiella pneumoniae Factors Implicated in Blocking Nuclear Factor κB (NF-κB) Signaling.

Klebsiella pneumoniae is an etiologic agent of community-acquired and nosocomial pneumonia. It has been shown that K. pneumoniae infections are characterized by reduced early inflammatory response.

Molecular and chemical analysis of the lipopolysaccharide from Aeromonas hydrophila strain AH-1 (Serotype O11).

A group of virulent Aeromonas hydrophila, A. sobria, and A. veronii biovar sobria strains isolated from humans and fish have been described; these strains classified to serotype O11 are serologically related by their lipopolysaccharide (LPS) O-antigen (O-polysaccharide), and the presence of an S-layer consisting of multiple copies of a crystalline surface array protein with a molecular weight of 52 kDa in the form of a crystalline surface array which lies peripheral to the cell wall.

Role of Aeromonas hydrophila flagella glycosylation in adhesion to Hep-2 cells, biofilm formation and immune stimulation.

Polar flagellin proteins from Aeromonas hydrophila strain AH-3 (serotype O34) were found to be O-glycosylated with a heterogeneous heptasaccharide glycan. Two mutants with altered (light and strong) polar flagella glycosylation still able to produce flagella were previously obtained, as well as mutants lacking the O34-antigen lipopolysaccharide (LPS) but with unaltered polar flagella glycosylation. We compared these mutants, altogether with the wild type strain, in different studies to conclude that polar flagella glycosylation is extremely important for A.