Interactions of biofilm polysaccharides produced by human infective bacteria with molecules of the quorum sensing system. A microscopy and NMR study.

Biofilms are the most common lifestyle adopted by bacterial communities where cells live embedded in a self-produced hydrated matrix. Although polysaccharides are considered essential for matrix architecture, their possible functional roles are still rather unexplored. The primary structure of polysaccharides produced by Klebsiella pneumoniae and species of the Burkholderia cepacia Complex revealed a composition rich in rhamnose.

Bacillus subtilis EpsA-O: A novel exopolysaccharide structure acting as an efficient adhesive in biofilms.

Extracellular polysaccharides are crucial components for biofilm development. Although Bacillus subtilis is one of the most characterized Gram-positive biofilm model system, the structure-function of its exopolysaccharide, EpsA-O, remains to be elucidated. By combining chemical analysis, NMR spectroscopy, rheology, and molecular modeling, high-resolution data of EpsA-O structure from atom to supramolecular scale was obtained.

Limosilactobacillus fermentum strains MC1 and D12: Functional properties and exopolysaccharides characterization.

Lactic acid bacteria (LAB) produce a broad spectrum of exopolysaccharides (EPSs), commonly used as texturizers in food products. Due to their potential contribution to LAB probiotic properties, like adhesion to human epithelial cells and competitive exclusion of pathogens from human intestinal epithelial cells, this study was focussed on the structural and functional characterization of the EPSs produced by two Limosilactobacillus fermentum strains - MC1, originating from mother's milk, and D12, autochthonous from Croatian smoked fresh cheese. Whole-genome sequencing and functional annotation of both L.

Development and Application of a High-Throughput Method for the Purification and Analysis of Surface Carbohydrates from .

(Kp) is a Gram-negative bacterium, and a leading cause of neonatal sepsis in low- and middle-income countries, often associated with anti-microbial resistance. Two types of polysaccharides are expressed on the Kp cell surface and have been proposed as key antigens for vaccine design: capsular polysaccharides (known as K-antigens, K-Ags) and O-antigens (O-Ags). Historically, Kp has been classified using capsule serotyping and although 186 distinct genotypes have been predicted so far based on sequence analysis, many structures are still unknown.

serotype 33G: genetic, serological, and structural analysis of a new capsule type.

(the pneumococcus) is a bacterial pathogen with the greatest burden of disease in Asia and Africa. The pneumococcal capsular polysaccharide has biological relevance as a major virulence factor as well as public health importance as it is the target for currently licensed vaccines. These vaccines have limited valency, covering up to 23 of the >100 known capsular types (serotypes) with higher valency vaccines in development.

Microscopy and modelling investigations on the morphology of the biofilm exopolysaccharide produced by Burkholderia multivorans strain C1576.

Bacteria form very often biofilms where they embed in a self-synthesized matrix exhibiting a gel-like appearance. Matrices offer several advantages, including defence against external threats and the easiness of intercellular communication. In infections, biofilm formation enhances bacteria resistance against antimicrobials, causing serious clinical problems for patients' treatments.

The Effect of Mushroom Culture Filtrates on the Inhibition of Mycotoxins Produced by and .

Two of the mycotoxins of greatest agroeconomic significance are aflatoxin B (AFB), and ochratoxin A (OTA). It has been reported that extracts from some wood-decaying mushrooms, such as and showed the ability to inhibit AFB or OTA biosynthesis. Therefore, in our study, a wide screening of 42 isolates of different ligninolytic mushrooms was assayed for their ability to inhibit the synthesis of OTA in and AFB in , in order to find a metabolite that can simultaneously inhibit both mycotoxins.

The Bep gene cluster in Burkholderia cenocepacia H111 codes for a water-insoluble exopolysaccharide essential for biofilm formation.

Burkholderia cenocepacia is an opportunistic pathogen isolated from cystic fibrosis patients where it causes infections that are extremely difficult to treat with antibiotics, and sometimes have a fatal outcome. Biofilm is a virulence trait of B. cenocepacia, and is associated with infection persistence and increased tolerance to antibiotics.

The Human Milk Microbiota Produces Potential Therapeutic Biomolecules and Shapes the Intestinal Microbiota of Infants.

Human milk not only provides a perfect balance of nutrients to meet all the needs of the infant in the first months of life but also contains a variety of bacteria that play a key role in tailoring the neonatal faecal microbiome. Microbiome analysis of human milk and infant faeces from mother-breastfed infant pairs was performed by sequencing the V1-V3 region of the 16S rRNA gene using the Illumina MiSeq platform. According to the results, there is a connection in the composition of the microbiome in each mother-breastfed infant pair, supporting the hypothesis that the infant's gut is colonised with bacteria from human milk.

Rapid generation of Shigella flexneri GMMA displaying natural or new and cross-reactive O-Antigens.

Generalized modules for membrane antigens (GMMA) are exosomes released from engineered Gram-negative bacteria and represent an attractive vaccine platform for the delivery of the O-Antigen (OAg), recognized as the key target for protective immunity against several pathogens such as Shigella. Shigella is a major cause of disease in Low- and Middle-Income countries and the development of a vaccine needs to deal with its large serotypic diversity. All S.

Pellicle Biofilm Formation in J2315 is Epigenetically Regulated through WspH, a Hybrid Two-Component System Kinase-Response Regulator.

The chemosensory signal transduction system Wsp regulates biofilm formation and related phenotypes by influencing cyclic-di-GMP (c-di-GMP) levels in bacterial cells. This is typically achieved by activation of the diguanylate cyclase WspR, through phosphorylation of its phosphoreceiver domain. The Wsp system of Burkholderia cenocepacia J2315 is in one operon with the hybrid response regulator/histidine kinase but lacks the diguanylate cyclase which is located in a different operon.

Characterisation of a new cell wall teichoic acid produced by Listeria innocua ŽM39 and analysis of its biosynthesis genes.

Listeria innocua is genetically closely related to the foodborne human pathogen Listeria monocytogenes. However, as most L. innocua strains are non-pathogenic, it has been proposed as a surrogate organism for determining the efficacy of antimicrobial strategies against L.

Lyophilized alginate-based microspheres containing Lactobacillus fermentum D12, an exopolysaccharides producer, contribute to the strain's functionality in vitro.

Lactobacillus (Limosilactobacillus) fermentum D12 is an exopolysaccharide (EPS) producing strain whose genome contains a putative eps operon. Whole-genome analysis of D12 was performed to disclose the essential genes correlated with activation of precursor molecules, elongation and export of the polysaccharide chain, and regulation of EPS synthesis. These included the genes required for EPS biosynthesis such as epsA, B, C, D and E, also gt, wzx, and wzy and those involved in the activation of the precursor molecules galE, galT and galU.

Oligosaccharides Derived from Tramesan: Their Structure and Activity on Mycotoxin Inhibition in and .

Food and feed safety are of paramount relevance in everyday life. The awareness that different chemicals, e.g.

The biofilm of Burkholderia cenocepacia H111 contains an exopolysaccharide composed of l-rhamnose and l-mannose: Structural characterization and molecular modelling.

Burkholderia cenocepacia belongs to the Burkholderia Cepacia Complex, a group of 22 closely related species both of clinical and environmental origin, infecting cystic fibrosis patients. B. cenocepacia accounts for the majority of the clinical isolates, comprising the most virulent and transmissible strains.

Proteomic Studies of the Biofilm Matrix including Outer Membrane Vesicles of C1576, a Strain of Clinical Importance for Cystic Fibrosis.

Biofilms are aggregates of microbial cells encased in a highly hydrated matrix made up of self-produced extracellular polymeric substances (EPS) which consist of polysaccharides, proteins, nucleic acids, and lipids. While biofilm matrix polysaccharides are unraveled, there is still poor knowledge about the identity and function of matrix-associated proteins. With this work, we performed a comprehensive proteomic approach to disclose the identity of proteins associated with the matrix of biofilm-growing C1576 reference strain, a cystic fibrosis clinical isolate.

The Exopolysaccharide Cepacian Plays a Role in the Establishment of the - Symbiosis.

is a rhizobial strain that belongs to the beta-proteobacteria, a group known to form efficient nitrogen-fixing symbioses within root nodules of several legumes, including the agriculturally important common bean. The establishment of the symbiosis requires the exchange of rhizobial and plant signals such as lipochitooligosaccharides (Nod factors), polysaccharides, and flavonoids. Inspection of the genome of the competitive rhizobium revealed the presence of several polysaccharide biosynthetic gene clusters.

Determination of the capsular polysaccharide structure of the Klebsiella pneumoniae ST512 representative strain KPB-1 and assignments of the glycosyltransferases functions.

Klebsiella pneumoniae strain KPB-1 was isolated in early 2011 from the pleural fluid of an inpatient admitted at an Italian hospital. It was characterized to produce the KPC-3 carbapenemase and to belong to sequence type 512, a derivative of sequence type 258 clade II characterized by the cps-2 gene cluster. The K-antigen of K.

H111 Produces a Water-Insoluble Exopolysaccharide in Biofilm: Structural Determination and Molecular Modelling.

Biofilms are a multicellular way of life, where bacterial cells are close together and embedded in a hydrated macromolecular matrix which offers a number of advantages to the cells. Extracellular polysaccharides play an important role in matrix setup and maintenance. A water-insoluble polysaccharide was isolated and purified from the biofilm produced by strain H111, a cystic fibrosis pathogen.

The polysaccharide extracted from the biofilm of Burkholderia multivorans strain C1576 binds hydrophobic species and exhibits a compact 3D-structure.

Microorganisms often grow in communities called biofilms where cells are imbedded in a complex self-produced biopolymeric matrix composed mainly of polysaccharides, proteins, and DNA. This matrix, together with cell proximity, confers many advantages to these microbial communities, but also constitutes a serious concern when biofilms develop in human tissues or on implanted prostheses. Although polysaccharides are considered the main constituents of the matrices, their specific role needs to be clarified.

Structure of the capsular polysaccharide of the KPC-2-producing Klebsiella pneumoniae strain KK207-2 and assignment of the glycosyltransferases functions.

Klebsiella pneumoniae strain KK207-2 was isolated in 2010 from a bloodstream infection of an inpatient at an Italian hospital. It was previously found to produce the KPC-2 carbapenemase and to belong to clade 1 of sequence type 258. Genotyping of the conserved wzi and wzc genes from strain KK207-2 yielded contrasting results: the wzc-based method assigned the cps to a new K-type, while the wzi-based method assigned it to the known K41 K-type.

Influence of Bacterial Biofilm Polysaccharide Structure on Interactions with Antimicrobial Peptides: A Study on .

Balneotherapy is a clinically effective complementary approach in the treatment of low-grade inflammation- and stress-related pathologies. The biological mechanisms by which immersion in mineral-medicinal water and the application of mud alleviate symptoms of several pathologies are still not completely understood, but it is known that neuroendocrine and immunological responses—including both humoral and cell-mediated immunity—to balneotherapy are involved in these mechanisms of effectiveness; leading to anti-inflammatory, analgesic, antioxidant, chondroprotective, and anabolic effects together with neuroendocrine-immune regulation in different conditions. Hormesis can play a critical role in all these biological effects and mechanisms of effectiveness.

Physico-chemical properties of aqueous drug solutions: From the basic thermodynamics to the advanced experimental and simulation results.

The physical chemical properties of aqueous solutions of model compounds are illustrated in relation to hydration and solubility issues by using three perspectives: thermodynamic, spectroscopic and molecular dynamics simulations. The thermodynamic survey of the fundamental backgrounds of concentration dependence and experimental solubility results show some peculiar behavior of aqueous solutions with several types of similar solutes. Secondly, the use of a variety of experimental spectroscopic devices, operating under different experimental conditions of dimension and frequency, has produced a large amount of structural and dynamic data on aqueous solutions showing the richness of the information produced, depending on where and how the experiment is carried out.