Deciphering the Chemical Language of the Immunomodulatory Properties of Veillonella parvula Lipopolysaccharide.

Veillonella parvula, prototypical member of the oral and gut microbiota, is at times commensal yet also potentially pathogenic. The definition of the molecular basis tailoring this contrasting behavior is key for broadening our understanding of the microbiota-driven pathogenic and/or tolerogenic mechanisms that take place within our body. In this study, we focused on the chemistry of the main constituent of the outer membrane of V.

The chemistry of gut microbiome-derived lipopolysaccharides impacts on the occurrence of food allergy in the pediatric age.

Food allergy (FA) in children is a major health concern. A better definition of the pathogenesis of the disease could facilitate effective preventive and therapeutic measures. Gut microbiome alterations could modulate the occurrence of FA, although the mechanisms involved in this phenomenon are poorly characterized.

Extraction, Purification, and Chemical Degradation of LPS from Gut Microbiota Strains.

It is estimated that more than 500 different bacterial species colonize the human gut, and they are collectively known as the gut microbiota. Such a massive bacterial presence is now considered an additional organ of the human body, thus becoming the object of an intense and daily growing research activity. Gram-negative bacteria represent a large percentage of the gut microbiota strains.

Structural determination of the lipid A from the deep-sea bacterium Zunongwangia profunda SM-A87: a small-scale approach.

Zunongwangia profunda SM-A87 is a deep-sea sedimentary bacterium from the phylum Bacteroidetes, representing a new genus of Flavobacteriaceae. It was previously investigated for its capability of yielding high quantities of capsular polysaccharides (CPS) with interesting rheological properties, including high viscosity and tolerance to high salinities and temperatures. However, as a Gram-negative, Z.

The Unusual Lipid A Structure and Immunoinhibitory Activity of LPS from Marine Bacteria KMM 6172 and KMM 6221.

Gram-negative bacteria experiencing marine habitats are constantly exposed to stressful conditions dictating their survival and proliferation. In response to these selective pressures, marine microorganisms adapt their membrane system to ensure protection and dynamicity in order to face the highly mutable sea environments. As an integral part of the Gram-negative outer membrane, structural modifications are commonly observed in the lipopolysaccharide (LPS) molecule; these mainly involve its glycolipid portion, i.

Lipopolysaccharide from Gut-Associated Lymphoid-Tissue-Resident Alcaligenes faecalis: Complete Structure Determination and Chemical Synthesis of Its Lipid A.

Alcaligenes faecalis is the predominant Gram-negative bacterium inhabiting gut-associated lymphoid tissues, Peyer's patches. We previously reported that an A. faecalis lipopolysaccharide (LPS) acted as a weak agonist for Toll-like receptor 4 (TLR4)/myeloid differentiation factor-2 (MD-2) receptor as well as a potent inducer of IgA without excessive inflammation, thus suggesting that A.

A chronic strain of the cystic fibrosis pathogen Pandoraea pulmonicola expresses a heterogenous hypo-acylated lipid A.

Pandoraea sp. is an emerging Gram-negative pathogen in cystic fibrosis causing severe and persistent inflammation and damage of the lungs. The molecular mechanisms underlying the high pathogenicity of Pandoraea species are still largely unknown.

Pairing LPS Structure with Its Immunomodulatory Effects on Human Cellular Models.

The gut microbiota guide the development of the host immune system by setting a systemic threshold for immune activation. Lipopolysaccharides (LPSs) from gut bacteria are able to trigger systemic and local proinflammatory and immunomodulatory responses, and this capability strongly relies on their fine structures. Up to now, only a few LPS structures from gut commensals have been elucidated; therefore, the molecular motifs that may be important for LPS-mammalian cell interactions at the gut level are still obscure.