Fructosan form Paenibacillus kribbensis PS04 enhance disease resistance against Rhizoctonia solani and tobacco mosaic virus

BACKGROUND: Rice sheath blight (caused by Rhizoctonia solani) and tobacco mosaic virus are very important plant diseases, causing a huge loss in global crop production. Paenibacillus kribbensis PS04 is a broad-spectrum biocontrol agent, used for controlling these diseases. Previously, extracellular polysaccharides (EPS) from P. kribbensis PS04 had been purified and their structure was inferred to be fructosan. This study aimed to evaluate the effects of exogenous EPS treatment on plant­pathogen interactions. RESULTS: Plant defense genes such as phenylalanine ammonia-lyase, catalase, chitinase, allene oxide synthase, and PR1a proteins were significantly induced by exogenous EPS treatment. Moreover, subsequent challenge of EPSpretreated plants with the pathogens (R. solani or tobacco mosaic virus) resulted in higher expression of defenseassociated genes. Increased activities of defense-associated enzymes, total phenols, and flavonoids were also observed in EPS pretreated plants. The contents of malondialdehyde in plants, which act as indicator of lipid peroxidation, were reduced by EPS treatment. CONCLUSIONS: This study comprehensively showed that EPS produced from P. kribbensis PS04 enhances disease resistance in plants by the activation of defense-associated genes as well as through the enhancement of activities of defense-related enzymes.

Antibacterial activity of the nisin-containing single-bond universal adhesive / 口腔疾病防治

Objective@#To investigate the antibacterial activity to Streptococcus mutans of a nisin-containing single-bond universal adhesive.@*Methods@#Nisin was mixed into the bonding agent to produce concentrations ranging from 0.01 g/mL to 0.05 g/mL for the experiments, and adhesive without nisin was used as the control. Dentin-resin specimens were prepared for the microtensile strength test to evaluate changes in the bonding strength. The proper concentrations were selected for more tests. ① An agar diffusion test was applied with filter paper to detect the release of nisin, and adhesive without nisin was used as the negative control, 0.01 g/mL Nisin aqueous solution was used as the positive control. ② Solidification; resin adhesive specimens were prepared for the assessment of direct contact inhibition activity. ③ Confocal laser scanning microscopy was used to examine the effect of the adhesive on the biological film activity and the ability of Streptococcus mutans to produce extracellular polysaccharides. @*Results @#Nisin did not significantly reduce the bond strength of the modified adhesive at 0.01-0.03 g/mL (P < 0.05); these concentrations were selected for the subsequent antibiosis experiment. Rings could not be observed in the agar diffusion test, except for in the group of adhesive modified with 0.01-0.03 g/mL nisin. Resin adhesive with 0.01-0.03 g/mL nisin could significantly inhibit the proliferation of Streptococcus mutans on the surface of the specimens. The confocal laser scanning microscopy results indicate that only the adhesive resin modified with nisin could reduce the bacteria in the biofilm and the production of extracellular polysaccharides.@*Conclusion@#Single-bond universal adhesive with 0.01-0.03 g/mL nisin can inhibit the growth of Streptococcus mutans and its biofilms on the bonding interface, as well as decrease the production of extracellular polysaccharides, and thus has the potential to decrease the occurrence of secondary caries.

Effects of extracellular polysaccharides from Paecilomyces Lilacinuson on phagocytosis function of mouse bone marrow-derived dendritic cells / 重庆医学

Objective To investigate the effects of Paecilomyces Lilacinuson extracellular polysaccharides on the phenotypic and function maturity of mouse dendritic ceils.Methods Mononuclear cells were isolated from the mouse bone marrow cavity and added with cytokines for obtaining the recombinant mouse granulocyte-macrophagocyte colony stimulating factor(rmGM-CSF),recombinant mouse interleukin 4(rmIL-4) was induced to differentiated to immature DCs.Then different concentrations of extracellular polysaccharides were used to conduct the intervention.The mature DCs surface marker CD11c,major histocompatibility complex Ⅱ (MHC Ⅱ),CD80,CD86 molecular expression and phagocytosing FITC-dextran ability was detected by the flow cytometry.The effect of the polysaccharides on DCs Toll-like receptor(TLR)2 mRNA and TLR4 mRNA expression was detected by RT-PCR.Results After 400 μg/mL polysaccharides action for 48 h,the expression of DCs surface molecules such as CD11c,MHC Ⅱ,CD80 and CD86 was significantly up-regulated compared with the blank control group (P＜0.05);after the polysaccharides action,the ability of DCs phagocytosing FITC-dextran was decreased,especially the effects of 300,400 μg/mL of polysaccharides were more significant compared with the control group (P＜0.05).In addition,the polysaccharides could down-regulate the expression of TLR2 mRNA and TLR4 mRNA in DCs,the DCs down-regulation effect after 100-400 μg/mL polysaccharides treatment,the difference compared with the blank control group was statistically significant(P＜0.05).Conclusion The extracellular polysaccharides can up-regulate the expression of DCs surface CD11c,MHC Ⅱ,CD80 and CD 86 molecules,decreases the phagocytosis ability and down-regulates the expression of TLR2 mRNA and TLR4 mRNA,which preliminarily indicates that the polysaccharides could stimulate the differentiation and maturation of murine DCs.

Effects of extracellular polysaccharides from Paecilomyces Lilacinuson on function of mouse bone marrow-derived dendritic cells / 中国免疫学杂志

Objective:To investigate the effects of the Paecilomyces Lilacinuson extracellular polysaccharides on the phenotypic and maturation of murine dendritic cells. Methods: Imature DCs were induced in vitro from the murine bone marrow cells in the presence of rmGM-CSF and rmIL-4, and then they were cultured with different dosage of the extracellular polysaccharides. The morphological characterization was analyzed under microscopy. The expressions of the DCs surface costimulating factors and phagocytic function to FITC-dextran were detected by flow cytometry. The level of IL-12 secreted by DCs was observed by ELISA. At the same time the influence of DCs on the proliferation of T cells was determined by MTT. Results:Treating with the polysaccharides for 48 h could up-regulate the expression of DCs surface molecules,such as CD11c,MHCⅡ,CD80 and CD86,and the 400 μg/ml was the optimal dose,comparing with the blank control group, the difference was significant (P<0. 01), contrast to LPS control group that was not different ( P<0. 05 ) . The uptaking FITC-dextran ability of the DCs treated with 300 μg/ml and 400 μg/ml polysaccharides was significant lower than the unstimulated DCs(P<0. 05). At the same time the extract at different concentration could distinctly enhance the proliferation of T cells by DCs too. Conclusion:The extracellular polysaccharides could stimulate the maturation of dendritic cells and induce the production of mature dendritic cells.

Extracellular polysaccharide production by a strain of Pleurotus djamor isolated in the south of Brazil and antitumor activity on Sarcoma 180

Polysaccharides with medicinal properties can be obtained from fruiting bodies, mycelium and culture broth of several fungus species. This work was carried out in batch culture using a stirred tank reactor with two different initial glucose concentrations (40-50 g/L) and pH values (3.0-4.0) to enhance extracellular polysaccharides production by Pleurotus djamor UNIVILLE 001 and evaluate antitumor effect of intraperitonial administration of Pleurotus djamor extract on sarcoma 180 animal model. According to factorial design, the low pH value (pH 3.0) led to a gain of 1.6 g/L on the extracellular polysaccharide concentration, while glucose concentration in the tested range had no significant effect on the concentration of polysaccharide. With 40 g/L initial glucose concentration and pH 3.0, it was observed that yield factor of extracellular polysaccharide on substrate (Y P/S = 0.072) and maximum extracellular polysaccharide productivity (Q Pmax = 11.26 mg/L.h) were about 188% and 321% respectively higher than those obtained in the experiment performed at pH 4.0. Under these conditions, the highest values of the yield factor of biomass on substrate (Y X/S = 0.24) and maximal biomass productivity (Q Xmax = 32.2 mg/L.h) were also reached. In tumor response study, mean tumor volume on the 21th day was 35.3 cm³ in untreated group and 1.6 cm³ in treated group (p = 0.05) with a tumor inhibition rate of 94%. These impressive results suggests an inhibitory effect of P.djamor extract on cancer cells.

Glycolytic activities in size-fractionated water samples: emphasis on rhamnosidase, arabinosidase and fucosidase activities

Glycolytic activities of eight enzymes in size-fractionated water samples from a eutrophic tropical reservoir are presented in this study, including enzymes assayed for the first time in a freshwater environment. Among these enzymes, rhamnosidase, arabinosidase and fucosidase presented high activity in the free-living fraction, while glucosidase, mannosidase and galactosidase exhibited high activity in the attached fraction. The low activity registered for rhamnosidase, arabinosidase and fucosidase in the attached fraction seemed contribute to the integrity of the aggregate and based on this fact, a protective role for these structures was proposed. The presented enzyme profiles and the differences in the relative activities probably reflected the organic matter composition as well as the metabolic requirements of the bacterial community, suggesting that bacteria attached to particulate matter had phenotypic traits distinct from those of free-living bacteria.

Activity of glycosidases from freshwater heterotrophic microorganisms on the degradation of extracellular polysaccharide produced by Anabaena spiroides (Cyanobacteria)

The activity of specific glycosidases during the degradation of the extracellular polysaccharide (EPS) produced by Anabaena spiroides was determined using MUF-substrates (MUF-monosaccharides). Polysaccharide degradation was found to occur in a two-phase process. The first consisted of high enzymatic activity that consumed 41% of the EPS at a relatively high rate, while the second consumed the remaining polysaccharide (59%) at a slower rate. A transition phase from the higher to the slower degradation rates was marked by a replacement of bacterial populations from coccoid to bacillus cells. During the degradation process, the bacterial biomass increased with the decrease of EPS, as revealed by bacterial cell counts. The enzymatic activity detected through the substrates MUF-alpha-D- and MUF-beta-D-glucoside was higher than that detected by other substrates tested. The remaining glycosides were MUF-alpha-L-rhamnopyranoside, MUF-beta-D-galactoside, MUF-alpha-D-mannopyranoside, MUF-beta-D-fucoside, MUF-beta-D-mannopyranoside, MUF-alpha-L-arabinopyranoside, and MUF-beta-L-fucoside. The fluorescence emitted by each MUF-substrate was proportional to the concentration of the corresponding monosaccharide in A. spiroides EPS. This demonstrates the susceptibility of EPS produced by A. spiroides to enzymatic attack by bacterial populations.

A atividade de glicosidases durante a degradação do polissacarídeo extracelular (EPS) produzido por Anabaena spiroides foi detectada e quantificada utilizando-se MUF-substratos (MUF-monossacarídeos). O consumo total do polissacarídeo efetuou-se em duas fases, uma primeira de alta atividade enzimática que rapidamente consumiu 41% do polissacarídeo e uma segunda, mais lenta, que consumiu o polissacarídeo restante (59%). A mudança de fase coincidiu com a sucessão de uma população de bactérias cocóides por outra de bacilos. A biomassa bacteriana, quantificada por contagens de células, aumentou com a degradação do EPS. As atividades registradas através dos substratos 4-MUF-alfa-D- e 4-MUF-beta-D- glicosídeo foram mais altas quando comparadas aos demais substratos testados que foram: MUF-alfa-L-ramnopiranosídeo, MUF-beta-D-galactosídeo, MUF-alfa-D-manopiranosídeo, MUF-beta-D-fucosídeo, MUF-beta-D-manopiranosídeo, MUF-alfa-L-arabinopiranosídeo, e MUF-beta-L-fucosídeo. A fluorescência emitida a partir de cada um dos diferentes MUF-substratos foi, de modo geral, proporcional à concentração dos monossacarídeos correspondentes constituintes do polissacarídeo, um indício da susceptibilidade ao ataque enzimático microbiano do EPS produzido por A. spiroides.

Phylogenetic analysis of antarctic bacterium Pseudoalteromonas sp.S-15-13 and the effect of its extracellular polysaccha ride on proliferation of murine lymphocytes / 中国海洋药物

Objective To investigate the screening of the Antarctic bacteria producing the extracellular polysaccharides(EPS),identification of the bacterium S-15-13 producing higher EPS by 16SrDNA,and the effects of the extracellular polysaccharide(EPSⅠ)on the cellular immune response in mice. Methods The Antarctic bacteria producing extracellular polysaccharide were screened by microscope observation and staining method;the phylogenetic position of S-15-13 was determined on the basis of amplification,comparison and analysis of almost complete 16S rDNA sequence and the effect of its extracellular polysaccharide on proliferation of murine lymphocytes was determined by method of Heek.Results and Conclusion Out of 57 strains of the Antarctic bacteria,27 strains were found to produce EPS according to the staining technique.The result of 16SrDNA demonstrated that strain S-15-13 belong to the genus Pseudoalteromonas sp.The purified fractionⅠ(EPSⅠ) produced by the bacterial strain S-15-13 obviously promoted proliferation of lymphocytes when used alone or with(Con A.)