Structural characterization of the O-polysaccharide isolated from Franconibacter helveticus LMG23732(T)

The structure of the O-polysaccharide isolated from pectinolytic gram-negative bacterium Dickeya aquatica IFB0154 is different from the O-polysaccharides of other Dickeya species

The species Dickeya aquatica was established in 2014 after the genomic characterization of the pectinolytic bacteria isolated from water. It was demonstrated that D. aquatica was able to cause symptoms of soft rot on the fruit of tomato and cucumber. According to earlier works, lipopolysaccharides are regarded as an important virulence factor of Pectobacteriaceae. An O-specific polysaccharide containing d-Fuc and l-Rha was obtained by mild acid hydrolysis of the lipopolysaccharide of D. aquatica IFB0154 (strain Dw044 isolated in Finland). By means of compositional analyses and NMR spectroscopy, the chemical repeating unit of the polymer was identified as a linear disaccharide of the structure shown below. The rhamnose residue was partially acetylated at O-2 or O-3. OAc (~40%) ↓₂ →3)-α-d-Fucp-(1 → 4)-α-l-Rhap-(1→ ↑³ OAc (~30%) The O-polysaccharides isolated from Dickeya dianthicola IFB0485 and Dickeya zeae IPO946 have a different structure, identical to that previously described for several strains of Dickeya solani and Dickeya dadantii 3937.

Sida hermaphrodita seeds as the source of anti - Candida albicans activity

Sida hermaphrodita is a perennial herbaceous plant with potential economic importance; however, there is no information about its antimicrobial properties. The aim of our study was to analyze the morphology and metabolic activity of Candida albicans cells after exposure to the extract from S. hermaphrodita seeds, determine its cytotoxicity against human skin fibroblasts and carry out chemical analysis of the extract. Microscopic analysis showed that the crude seed extract (CSE) caused a significant decrease in the metabolic activity of fungal cells, clear cell deformation, and budding disturbances. The analysis of cytotoxicity showed no influence of the extract on the fibroblasts. The CSE and seed extract after dialysis (DSE) were analyzed using electrophoretic, chromatographic, and spectroscopic methods. SDS-PAGE electrophoresis showed the presence of proteins and carbohydrate compounds in the extract. The Raman spectroscopy analysis of the DSE confirmed the presence of proteins, while FTIR analyses revealed the occurrence of albumin-type proteins. The NMR and GC-MS analyses showed the presence of carbohydrates in the seed extract. The MALDI and ESI LC-MS/MS analysis of the CSE and the DSE fractions revealed the occurrence of vicilin-type and plant lipid transfer proteins. The seed extract is a promising formulation to use in C. albicans infections.

The uniform structure of O-polysaccharides isolated from Dickeya solani strains of different origin

O-polysaccharides were isolated from lipopolysaccharides obtained from four different strains of plant pathogenic bacteria belonging to the species Dickeya solani: two of them were isolated in Poland (IFB0099 and IFB0158), the third in Germany (IFB0223) and the last one, D. solani Type Strain IPO2222, originated from the Netherlands. In addition, the O-polysaccharide of a closely related species D. dadantii strain 3937 was isolated. The purified polysaccharides of the five strains were analyzed using NMR spectroscopy and chemical methods. Sugar and methylation analyses, including absolute configuration assignment, together with NMR data revealed that all O-polysaccharides tested are homopolymers of 6-deoxy-d-altrose (d-6dAlt) the following structure: →2)-β-d-6dAltp-(1→.