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Acetobacter pasteurianus is an acetic acid-producing Gram-negative bacterium commonly found associated with plants and plant products and widely used in the production of fermented foods, such as kefir and vinegar. Due to the acid conditions of the bacterium living habitat, uncommon structural features composing its cell envelope are expected. In the present work we have investigated the A. pasteurianus CIP103108 lipopolysaccharide (LPS) structure and immunoactivity. The structure of the lipid A and of two different O-polysaccharides was assessed. Furthermore, immunological studies with human cells showed a low immunostimulant activity of the isolated LPS, in addition to a slight capability to lower the NF-kB activation upon stimulation by toxic LPS.

Gram-negative bacteria, innate immunity, lipopolysaccharides (LPS), Acetobacter pasteurianus, MD2-TLR4

NCBI PubMed ID: 30098357
Publication DOI: 10.1016/j.ijbiomac.2018.08.035
Journal NLM ID: 7909578
Publisher: Butterworth-Heinemann
Correspondence: silipo@unina.it
Institutions: Department of Chemical Sciences, University of Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, I-80126 Napoli, Italy, IRD, Laboratoire des Symbioses Tropicales et Mediterraneennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J - Campus de Baillarguet, 34398 Montpellier Cedex 5, France, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy, Junior Group of Allergobiochemistry, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany, Airway Research Center North (ARCN), German Center for Lung Research, Borstel, Germany
Methods: 13C NMR, 1H NMR, methylation, gel filtration, NMR-2D, GC-MS, acid hydrolysis, GLC, mild acid hydrolysis, DOC-PAGE, MS/MS, MALDI-TOF MS, composition analysis, TLR4 activation assay

Lipopolysaccharide (LPS) is a crucial constituent of the outer membrane of most Gram-negative bacteria, playing a fundamental role in the protection of bacteria from environmental stress factors, in drug resistance, in pathogenesis, and in symbiosis. During the last decades, LPS has been thoroughly dissected, and massive information on this fascinating biomolecule is now available. In this Review, we will give the reader a third millennium update of the current knowledge of LPS with key information on the inherent peculiar carbohydrate chemistry due to often puzzling sugar residues that are uniquely found on it. Then, we will drive the reader through the complex and multifarious immunological outcomes that any given LPS can raise, which is strictly dependent on its chemical structure. Further, we will argue about issues that still remain unresolved and that would represent the immediate future of LPS research. It is critical to address these points to complete our notions on LPS chemistry, functions, and roles, in turn leading to innovative ways to manipulate the processes involving such a still controversial and intriguing biomolecule.

Lipopolysaccharide, LPS, structure, Pathogenesis, carbohydrate, function, gram negative bacteria

NCBI PubMed ID: 34286971
Publication DOI: 10.1021/acs.chemrev.0c01321
Journal NLM ID: 2985134R
Publisher: Chem Rev
Correspondence: Antonio Molinaro
Institutions: Department of Chemical Sciences, University of Naples Federico II, via Cinthia 4, 80126 Naples, Italy, Task Force on Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy, Research Center Borstel Leibniz Lung Center, Parkallee 4a, 23845 Borstel, Germany, Department of Agricultural Sciences, University of Naples Federico II, Via Universita 96, 80055 Portici, Naples, Italy, Department of Chemistry, School of Science, Osaka University, 1-1 Osaka University Machikaneyama, Toyonaka, Osaka 560-0043, Japan

Lipid A of Gram-negative bacteria is known to represent a central role for the immunological activity of endotoxin. Chemical structure and biosynthetic pathways as well as specific receptors on phagocytic cells had been clarified by the beginning of the 21st century. Although the lipid A of enterobacteria including Escherichia coli share a common structure, other Gram-negative bacteria belonging to various classes of the phylum Proteobacteria and other taxonomical groups show wide variety of lipid A structure with relatively decreased endotoxic activity compared to that of E. coli. The structural diversity is produced from the difference of chain length of 3-hydroxy fatty acids and non-hydroxy fatty acids linked to their hydroxyl groups. In some bacteria, glucosamine in the backbone is substituted by another amino sugar, or phosphate groups bound to the backbone are modified. The variation of structure is also introduced by the enzymes that can modify electrostatic charges or acylation profiles of lipid A during or after its synthesis. Furthermore, lipid A structure can be artificially modified or engineered by the disruption and introduction of biosynthetic genes especially those of acyltransferases. These technologies may produce novel vaccine adjuvants or antagonistic drugs derived from endotoxin in the future.

Lipopolysaccharide, lipid A, endotoxin, chemical structure, fatty acid, engineering

NCBI PubMed ID: 33668925
Publication DOI: 10.3390/ijms22052281
Journal NLM ID: 101092791
Publisher: Basel, Switzerland: MDPI
Correspondence: kawahara@kanto-gakuin.ac.jp
Institutions: Department of Biosciences, College of Science and Engineering, Kanto Gakuin University, Yokohama, Kanagawa 236-8501, Japan