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Here we describe the analysis of the structure of the lipopolysaccharide (LPS) from Caulobacter crescentus strain JS1025, a derivative of C. crescentus CB15 NA1000 with an engineered amber mutation in rsaA, leading to the loss of the protein S-layer and gene CCNA_00471 encoding a putative GDP-l-fucose synthase. LPS was isolated using an aqueous membrane disruption method. Polysaccharide and core oligosaccharide were produced by mild acid hydrolysis and analyzed by nuclear magnetic resonance spectroscopy and chemical methods. Spectra revealed the presence of two polysaccharides, one of them, a rhamnan, could be removed using periodate oxidation. Another polymer, built from 4-amino-4-deoxy-d-rhamnose (perosamine), mannose, and 3-O-methyl-glucose, should be the O-chain of the LPS according to genetic data. The attribution of the rhamnan as a part of LPS or a separate polymer was not possible.

Lipopolysaccharide, nuclear magnetic resonance, extracellular polysaccharides, Caulobacter crescentus

NCBI PubMed ID: 25498010
Publication DOI: 10.1016/j.carres.2014.10.003
Journal NLM ID: 0043535
Publisher: Elsevier
Correspondence: J. Smit
Institutions: National Research Council of Canada, 100 Sussex Drive, Building Sussex, Room 3079, Ottawa, Ontario K1A 0R6, Canada, Department of Microbiology and Immunology, 2350 Health Sciences Mall, Life Sciences Centre, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
Methods: 13C NMR, 1H NMR, methylation, periodate oxidation, gel filtration, NMR-2D, GC-MS, SDS-PAGE, sugar analysis, TLC, 31P NMR, acid hydrolysis, mild acid hydrolysis, NMR-1D, reduction with NaBD4, de-N-acylation

Lipopolysaccharide, nuclear magnetic resonance, extracellular polysaccharides, Caulobacter crescentus

Diabetes mellitus, characterized by hyperglycemia and insulin resistance, is a disorder of the endocrine metabolic system which has emerged as a common chronic disease worldwide. Euglena gracilis polysaccharides have ideal development potential in the treatment of diabetes. However, their structure and bioactivity are largely unclear. A novel purified water-soluble polysaccharide (EGP-2A-2A) from E. gracilis with a molecular weight of 130.8 kDa consisted of xylose, rhamnose, galactose, fucose, glucose, arabinose, and glucosamine hydrochloride. The SEM image for EGP-2A-2A suggested a rough surface with the presence of globule-like protrusions. Methylation and NMR spectral analyses revealed that EGP-2A-2A was mainly composed of →6)-β-D-Galp-(1→2)-α-D-Glcp-(1→2)-α-L-Rhap-(1→3)-α-L-Araf-(1→6)-β-D-Galp-(1→3)-α-D-Araf-(1→3)-α-L-Rhap-(1→4)-β-D-Xylp-(1→6)-β-D-Galp-(1→ with complex branching structure. EGP-2A-2A significantly increased glucose consumption and glycogen content in IR-HeoG2 cells and modulates glucose metabolism disorders by regulating PI3K, AKT, and GLUT4 signaling pathways. EGP-2A-2A significantly suppressed TC, TG, and LDL-c levels, and enhanced that of HDL-c. EGP-2A-2A ameliorated abnormalities caused by disorders of glucose metabolism and the hypoglycemic activity of EGP-2A-2A may be mainly positively related to its high glucose content and the β-configuration in the main chain. These results suggested that EGP-2A-2A played an important role in alleviating disorders of glucose metabolism through insulin resistance and has the potential for development as a novel functional food with nutritional and health benefits.

polysaccharide, Structural characterization, Euglena gracilis, insulin resistance, type 2 diabetes

NCBI PubMed ID: 36906209
Publication DOI: 10.1016/j.ijbiomac.2023.12398
Journal NLM ID: 7909578
Publisher: Butterworth-Heinemann
Correspondence: C. Zhao
Institutions: College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou 362000, China, Fujian Province Key Laboratory for the Development of Bioactive Material from Marine Algae, Quanzhou Normal University, Quanzhou 362000, China, State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China, Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Methods: 13C NMR, 1H NMR, methylation, NMR-2D, GC-MS, sugar analysis, Western blotting, FTIR, HPLC, statistical analysis, cytotoxicity assay, HPGPC, SEM, TG, UV-VIS, inhibitory studies, TC, glucose uptake assay, IF

In this study, two extracellular polysaccharides (TEPS1 and TEPS2) were isolated from the endophytic fungus (Talaromyces purpureogenus) and purified by DEAE-Sepharose Fast Flow column using NaCl as gradient eluent. The HPLC analysis displayed that TEPS1 was composed of mannose (38.70%), ribose (25.02%), glucose (19.34%), and galactose (16.94%) while the TEPS2 composed by mannose (100%). The NMR results indicated that TEPS1 exhibited α-glycosidic configurations. The both polysaccharides, TEPS1 and TEPS2 were exhibited a good antioxidant activity in terms of DPPH, ABTS, and •OH scavenging. However, TEPS1 showed a higher antioxidant activity than TEPS2. The IC50 of TEPS1 were 32.16, 192.57, and 54.67 μg/mL-1, for DPPH, ABTS, and •OH radical scavenging, respectively. Furthermore, TEPS1 showed the high cellular antioxidant and wound healing activity in the human embryonic kidney (HEK293) cell line. Overall, these two polysaccharides were promising in antioxidant activity.

extracellular polysaccharides, Antioxidant activity, structure characteristics, Talaromyces purpureogenus

NCBI PubMed ID: 36260249
Publication DOI: 10.1007/s12010-022-04187-x
Journal NLM ID: 8208561
Publisher: Humana Press
Correspondence: M.H. Wang
Institutions: Department of Bio-Health Convergence, Kangwon National University, Chuncheon, 200-701, South Korea, Chuncheon Center, Korea Basic Science Institute (KBSI), Chuncheon, 24341, Republic of Korea
Methods: 13C NMR, 1H NMR, methylation, NMR-2D, GC-MS, sugar analysis, MALDI-TOF MS, FTIR, HPLC, CC, antioxidant activities, cytotoxicity assay, radical scavenging assay, isolation, UV-vis, wound healing assay