Isolation and characterization of 3-acetamido-3,6-dideoxy-L-glucose from the core oligosaccharides obtained from the aquatic gram-negative bacteria Aeromonas hydrophila and Vibrio anguillarum

1981 ◽  
Vol 59 (11-12) ◽  
pp. 877-879 ◽  
Author(s):  
Joseph H. Banoub ◽  
Derek H. Shaw

The amino sugar 3-acetamido-3,6-dideoxy-L-glucose has been isolated and characterized from the core oligosaccharide obtained from the bacterial lipopolysaccharides of Aeromonas hydrophila and Vibrio anguillarum. This is the first occasion in which a dideoxyamino sugar has been confirmed as a constituent of the core oligosaccharide rather than the O-polysaccharide.

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 646
Author(s):  
Rossella Di Guida ◽  
Angela Casillo ◽  
Antonietta Stellavato ◽  
Celeste Di Meo ◽  
Soichiro Kawai ◽  
...  

Lipopolysaccharides (LPS) are surface glycoconjugates embedded in the external leaflet of the outer membrane (OM) of the Gram-negative bacteria. They consist of three regions: lipid A, core oligosaccharide (OS), and O-specific polysaccharide or O-antigen. Lipid A is the glycolipid endotoxin domain that anchors the LPS molecule to the OM, and therefore, its chemical structure is crucial in the maintenance of membrane integrity in the Gram-negative bacteria. In this paper, we reported the characterization of the lipid A and OS structures from Pseudoalteromonas nigrifaciens Sq02-Rifr, which is a psychrotrophic Gram-negative bacterium isolated from the intestine of Seriola quinqueradiata. The immunomodulatory activity of both LPS and lipid A was also examined.


Author(s):  
Jianli Wang ◽  
Wenjian Ma ◽  
Yu Fang ◽  
Hao Liang ◽  
Huiting Yang ◽  
...  

Gram-negative bacteria are intrinsically resistant to antibiotics due to the presence of the cell envelope, but mechanisms are still not fully understood. In this study, a series of mutants that lack one or more major components associated with the cell envelope were constructed from Escherichia coli K-12 W3110. WJW02 can only synthesize Kdo 2 -lipid A which lacks the core oligosaccharide portion of lipopolysaccharide. WJW04, WJW07 and WJW08 were constructed from WJW02 by deleting the gene clusters relevant to the biosynthesis of exopolysaccharide, flagella and fimbria, respectively. WJW09, WJW010 and WJW011 cells cannot synthesize exopolysaccharide, flagella and fimbria, respectively. Comparing to the wild type W3110, mutants WJW02, WJW04, WJW07 and WJW08 cells showed decreased resistance to more than 10 different antibacterial drugs, but not the mutants WJW09, WJW010 and WJW011. This indicates that the core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in E. coli and the 1 st heptose in core oligosaccharide portion is critical. Furthermore, the removal of the core oligosaccharide of LPS leads to influences on cell wall morphology, cell phenotypes, porins, efflux systems, and the respond behaviors to antibiotic stimulation. The results demonstrated the important role of lipopolysaccharide on the antibiotic resistance of Gram-negative bacteria.


2015 ◽  
Vol 61 (6) ◽  
pp. 429-435 ◽  
Author(s):  
C.S. Neethu ◽  
K.M. Mujeeb Rahiman ◽  
A.V. Saramma ◽  
A.A. Mohamed Hatha

Isolation and characterization of heterotrophic Gram-negative bacteria was carried out from the sediment and water samples collected from Kongsfjord, Arctic. In this study, the potential of Arctic bacteria to tolerate heavy metals that are of ecological significance to the Arctic (selenium (Se), mercury (Hg), cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) was investigated. Quantitative assay of 130 isolates by means of plate diffusion and tube dilution methods was carried out by incorporation of different concentrations of metals. Growth in Se and Pb at a concentration of 3000 μg/L was significantly lower (P ≤ 0.0001) than at 2000 μg/L. The minimum inhibitory concentration for Cd and Hg was 50 μg/L (P ≤ 0.0001, F = 264.23 and P ≤ 0.0001, F = 291.08, respectively) even though in the tube dilution test, Hg-containing tubes showed much less growth, revealing its superior toxicity to Cd. Thus, the level of toxicity of heavy metals was found to be in the order of Hg > Cd > Cu > Zn > Pb > Se. Multiple-metal-resistant isolates were investigated for their resistance against antibiotics, and a positive correlation was observed between antibiotic and metal resistance for all the isolates tested. The resistant organisms thus observed might influence the organic and inorganic cycles in the Arctic and affect the ecosystem.


2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.


1977 ◽  
Vol 34 (8) ◽  
pp. 1244-1249 ◽  
Author(s):  
G. L. Bullock ◽  
H. M. Stuckey

Filtration (25 nm) and ultraviolet irradiation dosages of 13,100–29,400 microwatt seconds per square centimetre (μW∙s∙cm−2) effected a 99.98–100% reduction of five gram-negative fish pathogens — Aeromonas salmonicida, A. hydrophila, Vibrio anguillarum, Pseudomonas fluorescens, and the enteric redmouth organism in 12.5 °C clear spring water or spring water containing particulate matter. Filtration and a dosage of 4500 μW∙s∙cm−2 killed 99.83–100% of test strains in spring water and 4000–4750 μW∙s∙cm−2 killed 99.33–99.99% in water with particulate matter. Irradiation of unfiltered water containing particulate matter was less effective, especially at dosages of 5000 μW∙s∙cm−2 or less, which killed 97–99.94% of strains. Filtration and 13,100 μW∙s∙cm−2 irradiation of water containing A. salmonicida prevented transmission of furunculosis. Key words: ultraviolet irradiation, bacterial fish pathogens, water disinfection


2019 ◽  
Vol 6 (3) ◽  
pp. 467-478 ◽  
Author(s):  
Miranda J. Wallace ◽  
Suresh Dharuman ◽  
Dinesh M. Fernando ◽  
Stephanie M. Reeve ◽  
Clifford T. Gee ◽  
...  

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