The anti-cancer activity of polysaccharide prepared from Libyan dates (Phoenix dactylifera L.)

A glucan of cellular origin has been isolated from Libyan dates (Phoenix dactylifera L.) and the structure of the purified glucan was characterized using derivatisation methods including methylation, periodate oxidation, and acetolysis. Glucans were found to exhibit potent antitumor activity; this activity could be correlated to their (1→3)-β-d-glucan linkages. This is the first report on studies of antitumor active compounds occurring in dates.     

Polysaccharide conjugated laccase for the dye decolorization and reusability of effluent in textile industry

Nine different polysaccharides were screened for conjugation with laccase and evaluated for pH and thermal stability. All the polysaccharides decreased the thermal and pH stability of laccase at 50 °C and 60 °C, where conjugation with gum Arabic showing the most pronounced effect. Thermal instability of gum Arabic conjugated laccase was affirmed by differential scanning calorimeter while the structural changes in the conjugated laccase responsible for thermal instability was analysed by fluorescence spectrophotometer. The gum Arabic conjugated laccase showed an unusually high tolerance to sodium chloride, thermal instability and lower stability in alkaline conditions. Gum Arabic conjugated laccase was found to decolorize Remazol brilliant blue R in the textile effluent at a slower rate without any microbial growth which was unlike that observed in effluent treated with free laccase. Further, effluent treated with conjugated laccase enabled its reuse as liquor for the dyeing to get desired shade.     

Detection of polysaccharides and ultrastructural modification of the photobiont cell wall produced by two arginase isolectins fromXanthoria parietina

Morphological and structural studies carried out inXanthoria parietina reveal some fungal mechanisms to regulate both growth and development of the phycobiont as well as the number of photobiont cells present in the holobiont. This regulation is performed by phenolic acids and glycosyl-enzymes. An ultrastructural analysis using the polysaccharide detection technique PATAg shows that plasmolysis of cells occur when freshly isolated phycobionts are incubated with two arginase lectins (ABP, algal binding protein and SA, secreted arginase), with development of large cytoplasmic vesicles filled with amorphous polysaccharides that are exocyted to the periplasmic space. Finally, membranes of organelles and plasma membrane are altered and the cell wall is broken. The results presented here provide evidence of a possible fungus-to-algal action as deduced from the hemiparasitic symbiosis theory.