Structural characterization and high-efficiency prebiotic activity of the polysaccharide from Tremella aurantialba endophytic bacteria.

Herein, the low-molecular-weight heteropolysaccharide (designated as TABP), with a weight-average Mw of 5408 Da, was produced by the endophytic bacterium Bacillus sp. TAB, which was initially isolated from the fruiting bodies of the wild Tremella aurantialba. A relatively high TABP accumulation was obtained and enhanced to 6.94 g/L in 5 L fed-batch fermentation by high-density cultivation. Monosaccharide composition analysis showed that the TABP comprised arabinose, glucosamine, galactose, glucose, and mannose with a molar ratio of 0.073: 0.145: 0.406: 0.182: 0.195, respectively. Methylation and NMR analyses indicated that TABP contained 1,4-linked ß-d-Galp and 1,4-linked ß-d-Manp pyranosyl backbone, extensively substituted at the side chains to form a complex structure. Prebiotic potential analysis exhibited significant growth-promoting effects for various lactic acid bacteria by more than 90 %. Overall, this study initially provides valuable insights into the endophytic exopolysaccharides from T. aurantialba and their biological activity, which provides prospective sources of prebiotics for functional foods and aids in understanding the endophytes symbiosis mechanism in edible mushrooms.

Correction: Root colonization and growth promotion of soybean, wheat and Chinese cabbage by Bacillus cereus YL6.

[This corrects the article DOI: 10.1371/journal.pone.0200181.].

Root colonization and growth promotion of soybean, wheat and Chinese cabbage by Bacillus cereus YL6.

Although phosphate-solubilizing bacteria (PSBs) are used in agricultural production, comprehensive research on PSB that colonize the rhizosphere of different plants and promote plant growth is lacking. This study was conducted to examine the growth-promoting effects and colonizing capacity of strain YL6, a PSB. YL6 not only increased the biomass of soybean and wheat in pot experiments but also increased the yield and growth of Chinese cabbage under field conditions. The observed growth promotion was related to the capacity of YL6 to dissolve inorganic and organic phosphorus and to produce indole-3-acetic (IAA) and gibberellin (GA). After applying YL6 to soybean, wheat and Chinese cabbage, the rhizosphere soil available phosphorus (available P) content increased by 120.16%, 62.47% and 7.21%, respectively, and the plant total phosphorus content increased by 198.60%, 6.20% and 78.89%, respectively, compared with plants not treated with YL6. To examine plant colonization, YL6 labeled with green fluorescent protein (YL6-GFP) was inoculated into the plant rhizosphere and found to first colonize the root surface and hairs and then to penetrate into the intercellular spaces and vessels. Collectively, these results demonstrate that YL6 promotes the growth of three different crops and colonizes them in a similar manner. The findings therefore provide a solid foundation for probing the mechanisms by which PSB affect plant growth.

Guaiol--a naturally occurring insecticidal sesquiterpene.

The dichloromethane fraction of Ferula ferulaeoides was analyzed by GC and GC-MS, and thirty-four compounds were identified. The main component in the fraction, guaiol (37.0%) was separated by chromatographic methods and identified from spectroscopic data, including 1H and 13C NMR, and X-ray crystallographic diffraction. Guaiol showed significant inhibition of aphids at a concentration of 70 mg/L. It also showed good contact activities against the 4th instar larvae of Mythimna separate and 3rd instar larvae of Plutella xylostella, with LD50 values of 0.07 and 8.9 mg/larva, as well as fumigation activity against the 4th instar larvae ofM. separata and adult Musca domestica, with LC50 values of 3.5 microL/L and 16.9 microL/L, respectively.

Phytopathogenic fungal inhibitors from celery seeds.

Extract of celery (Apium graveolens L.) seeds was investigated against phytopathogenic fungi. The light petroleum extract showed promising inhibition activities in the tests against Rhizoctonia solani and Fusarium oxysporum f. sp. vasinfecum. Chromatographic separation of the extract gave 19 fractions, one of which, QCZ-4, possessed significant inhibitory rates of 64.6%, 88.4% and 54.7% at a concentration of 100 ppm against R. solani, F. oxysporium f. sp. vasinfecum and Alternaria alternata, respectively. Major components in the active fraction were identified by GC-MS as p-(2-aminoethyl)phenol (39.7%), 3-(3,4-dimethybenzoyl) propionic acid (32.6%) and p-heptylphenol (26.9%).

[Effects of PreS2 synthetic peptides on infiltrating T lymphocyte subgroups expression in hepatocellular carcinoma].

OBJECTIVES: To explore whether PreS2 can change the percentage of T lymphocyte subgroups and the ration of CD4+/CD8+ in hepatocellular carcinoma (HCC) caused by HBV. METHODS: The P120-146 region composed by the way of Merrifield, which was the most intensive antigen in PreS2 peptides, served as the antigen after dissolved in 0.01 mol/L PBS. 12 patients were chosed as the subjects, who were pathologically diagnosed as HCC after operation, were HBsAg-, HBeAg-, anti-HBc, and HBV DNA positive in serum, and expressed HBsAg in HCC tissue. The monocytes were isolated and cultured in 96 microplate with 1x 10(6) cells in every well, then the PreS2 synthetic peptides was added in at the doses of 1microg, 5microg, and 10microg, also IL-2 with 500 U was added in. Seven days later, the percentage of CD3+, CD4+, CD8+, and the ratio of CD4+/CD8+ were detected. RESULTS: It was found that the percentage of CD4+ increased significantly (t = 3.508, P < 0.01), and the ratio of CD4+/CD8+ decreasedly obviously (t = 2.235, P < 0.05) in the 5microg PreS2 synthetic peptides group, compared with those in the control group. The percentage of CD3+ rised markedly in the IL-2 group, compared with that in the control group. CONCLUSION: With proper doses, PreS2 is capable of changing the expression of T lymphocyte subgroups in HCC tissue, increasing the percentage of CD4+ obviously and changing the motionless state of CD8+, to make the carcinoma cell killed through the action of CD4+ and CD8+.