Evaluation of biocontrol efficacy of rhizosphere Pseudomonas aeruginosa for management of Phytophthora capsici of pepper.

A significant population of biocontrol microorganisms resides in the rhizosphere of plants, which can be utilized for plant disease control. To explore the potential of rhizosphere soil microorganisms as biocontrol agents against pepper blight, a bacterial strain Pa608 was screened from rhizosphere soil of pepper and identified as Pseudomonas aeruginosa through morphological characteristics and 16S rRNA sequences. The result showed that the strain Pa608 demonstrated antagonistic activity against Phytophthora capsici, effectively suppressing mycelial growth.

Degraded polysaccharides from Porphyra haitanensis: purification, physico-chemical properties, antioxidant and immunomodulatory activities.

To explore effect of the structural properties of porphyra haitanensis polysaccharide on its biological activity, degraded porphyra polysaccharides were separated and purified by Cellulose DEAE-52 and Sephadex G-100 chromatography, obtaining three purified components (P1, P2 and P3). All the three components were sulfate polysaccharides containing the repeating units of → 3) β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →, and → 3) β-D-galactose (1 → 4) α-L-galactose-6-S (1 →, and → 3) 6-O-methyl-β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →. The molecular weight of the three fractions was measured to be 300.

Purification, characterization and antioxidant activity of polysaccharides from Porphyra haitanensis.

In order to study the antioxidant activity of Porphyra haitanensis polysaccharides and the effect of their structure on the antioxidant activity, the Porphyra haitanensis polysaccharide (PHP), prepared by hot water extraction and alcohol precipitation, was separated and purified by Cellulose DEAE-52 ion exchange and Sephadex G-100 column chromatography. Three purified components including PHP1, PHP2 and PHP3 were obtained, and chemical composition analysis and structural characterization were performed. The in vitro free radical scavenging activity of the purified polysaccharide fractions and their ability to relieve oxidative stress in macrophage RAW264.