1.O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins.
Ghequire MG1, Dingemans J, Pirnay JP, De Vos D, Cornelis P, De Mot R. Microbiologyopen. 2014 Dec;3(6):875-84. doi: 10.1002/mbo3.210. Epub 2014 Sep 16.
Lectin-like bacteriocins of the LlpA family, originally identified in plant-associated bacteria, are narrow-spectrum antibacterial proteins composed of two tandemly organized monocot mannose-binding lectin (MMBL) domains. The LlpA-like bacteriocin of Pseudomonas aeruginosa C1433, pyocin L1, lacks any similarity to known P. aeruginosa bacteriocins. The initial interaction of pyocin L1 with target cells is mediated by binding to d-rhamnose, present in the common polysaccharide antigen of lipopolysaccharides (LPS), but the actual cytotoxic mechanism is unknown. In this study, we characterized the activity range of pyocin L1 and two additional L pyocins revealed by genome mining, representing two highly diverged LlpA groups in P. aeruginosa. The recombinant proteins exhibit species-specific antagonistic activities down to nanomolar concentrations against clinical and environmental P. aeruginosa strains, including several multidrug-resistant isolates.
2.A comb-like branched β-d-glucan produced by a Cordyceps sinensis fungus and its protective effect against cyclophosphamide-induced immunosuppression in mice.
Hu T1, Jiang C1, Huang Q2, Sun F1. Carbohydr Polym. 2016 May 20;142:259-67. doi: 10.1016/j.carbpol.2016.01.036. Epub 2016 Jan 19.
An exopolysaccharide (EPS) was fractionated from fermentation media of a Cordyceps sinensis fungus (Cs-HK1) by ethanol precipitation at 2/5 volume ratio of ethanol/media. Its structural characteristics were elucidated by FT-IR, GC, GC-MS, 1D and 2D NMR combined with periodate oxidation, Smith degradation, partial acid hydrolysis, and methylation analysis. Furthermore, the immunomodulatory activity of EPS was evaluated by the model of cyclophosphamide-induced immunosuppression. The results from monosaccharide composition and partial acid hydrolysis indicated that EPS almost consisted of glucose excluding a trace amount of mannose. GC-MS and NMR analysis further confirmed EPS had a linear backbone of (1→3)-β-d-glucopyranosyl residues with a single (1→6)-β-d-glucopyranosyl side-branching unit for every three β-d-glucopyranosyl residues, showing a comb-like β-d-glucan with short and intensive branches, which was responsible for high viscosity.
3.Purification, characterization and anti-diabetic activity of a polysaccharide from mulberry leaf.
Zhang Y1, Ren C2, Lu G2, Cui W2, Mu Z3, Gao H2, Wang Y2. Regul Toxicol Pharmacol. 2014 Dec;70(3):687-95. doi: 10.1016/j.yrtph.2014.10.006. Epub 2014 Oct 22.
In the present study, a high-purity polysaccharide from mulberry leaf (MLP) was purified and characterized, and its anti-diabetic effects were investigated in streptozotocin (STZ)-induced diabetic rats. Our results showed that the obtained MLP (purity 99.8%) was determined to be composed of d-arabinose, d-xylose, d-glucose, d-rhamnose and d-mannose with molar ratio of 1:2.13:6.53:1.04:8.73. Oral administration of MLP at 50-200mg/kgbodyweight daily for 5weeks significantly reduced the levels of fasting blood glucose (FBG), glycosylated serum protein (GSP), serum total cholesterol (TC), and serum triglyceride (TG), and increased the body weight, fasting insulin (FINS), C-peptide (C-P), liver glycogen, liver glucokinase, and serum high-density lipoprotein cholesterol (HDL-C). Moreover, MLP promoted marked pancreatic β-cell regeneration and insulin secretion, and reduced liver fat accumulation in diabetic rats. The treatment effect of MLP on diabetes was similar to the effect of antidiabetic drug glibenclamide.
4.[The synthesis of P1-[11-(anthracen-9-ylmethoxy)undecyl]-P2(2-Acetamido-2-deoxy-α-D-glucopyranosyl) diphosphate and the study of its acceptor properties in the enzymic reaction catalyzed by D-rhamnosyltransferase from Pseudomonas aeruginosa].
Vinnikova AN, Torgov VI, Utkina NS, Veselovsky VV, Druzhinina TN, Wang S, Brockhausen, Danilov LL. Bioorg Khim. 2015 Jan-Feb;41(1):121-3.
P1-[11-(Anthracen-9-ylmethoxy)undecyl]-P2-(2-acetamido-2-deoxy-α-D-glucopyranosyl) diphosphate, a fluorescent derivative of undecyl diphosphate 2-acetamido-2-deoxyglucose, was chemically synthesized. The ability of the compound to serve as acceptor substrate of D-rhamnose residue in the enzymatic reaction catalyzed by D-rhamnosyltransferase from Pseudomonas aeruginosa PAO1 was demonstrated.