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Sarangi N.P. Athukorala Khalid Y. Rashid Teresa de Kievit 《Biocontrol Science and Technology》2010,20(8):875-890
Pseudomonas chlororaphis strain PA23 has demonstrated excellent biocontrol in the canola phyllosphere. This bacterium produces the non-volatile antibiotics phenazine and pyrrolnitrin as well as the volatile antibiotics nonanal, benzothiazole and 2-ethyl-1-hexanol. In vitro experiments were conducted to study the effects of different mutations on the production of these three organic volatile antibiotics by PA23. In planta experiments in the greenhouse investigated the role of the non-volatile antibiotics on root colonization and biocontrol ability of PA23 against Sclerotinia sclerotiorum on sunflower. Analysis of phenazine- and pyrrolnitrin-deficient Tn mutants of PA23 revealed no differences in production of the three volatile antibiotics. On all sampling dates, PA23 applied alone or in combination with the mutants showed significantly higher (P = 0.05) root bacterial number and Sclerotinia wilt suppression (P = 0.05). Decline of the bacterial population seemed to be inversely proportional to/or negatively correlated with the number of antibiotics produced by PA23 but the relative importance of phenazine or pyrrolnitrin on root colonization and/or wilt suppression was not clear. In several cases, the strains producing at least one antibiotic maintained relatively higher bacterial numbers than non-producing strains. However, by 6 weeks after sowing, there was a rapid and significant (P = 0.05) increase in the proportion of introduced bacteria capable of producing at least one antibiotic over the total bacterial population. Furthermore, combining certain mutants with PA23 reduced the root colonization and biocontrol ability of PA23. Strain PA23-314 (gacS mutant) showed competitive colonization in comparison to the other mutants for most sampling dates. 相似文献
2.
Karawita R Senevirathne M Athukorala Y Affan A Lee YJ Kim SK Lee JB Jeon YJ 《Marine biotechnology (New York, N.Y.)》2007,9(4):479-490
The enzymatic extracts from seven species of microalgae (Pediastrum duplex, Dactylococcopsis fascicularis, Halochlorococcum porphyrae, Oltmannsiellopsis unicellularis, Achnanthes
longipes, Navicula sp. and Amphora coffeaeformis) collected from three habitats (freshwater, tidal pool, and coastal benthic) at Jeju Island in Korea were investigated for
their antioxidant activity. Of the extracts tested, the AMG 300 L (an exo 1, 4-α-d-glucosidase) extract of P. duplex, the Viscozyme extract of Navicula sp., and the Celluclast extract of A. longipes provided the most potential as antioxidants. Meanwhile, the Termamyl extract of P. duplex in an H2O2 scavenging assay exhibited an approximate 60% scavenging effect. In this study, we report that the DNA damage inhibitory
effects of P. duplex (Termamyl extract) and D. fascicularis (Kojizyme extract) were nearly 80% and 69% respectively at a concentration of 100 μg/ml. Thus, it is suggested that the microalgae
tested in this study yield promising DNA damage inhibitory properties on mouse lymphoma L 5178 cells that are treated with
H2O2. Therefore, microalgae such as P. duplex may be an excellent source of naturally occurring antioxidant compounds with potent DNA damage inhibition potential. 相似文献
3.
Evaluation of biomolecular interactions of sulfated polysaccharide isolated from Grateloupia filicina on blood coagulation factors 总被引:2,自引:0,他引:2
Athukorala Y Jung WK Park PJ Lee YJ Kim SK Vasanthan T No HK Jeon YJ 《Journal of microbiology and biotechnology》2008,18(3):503-511
An edible marine red alga, Grateloupia filicina, collected from Jeju Island of Korea was hydrolyzed by cheap food-grade carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, and Ultraflo) to investigate its anticoagulant activity. Among the tested enzymatic extracts of G. filicina, a Termamyl extract showed the highest anticoagulant activity. Anion-exchange chromatography on DEAE-cellulose and gelpermeation chromatography on Sepharose-4B were used to purify the active polysaccharide from the crude polysaccharide fraction of G. filicina. The purified sulfated polysaccharide (0.42 sulfate/total sugar) showed approximately 1,357 kDa molecular mass and was comprised mainly of galactose (98%) and 1-2% of glucose. The sample showed potential anticoagulant activity on activated partial thromboplastin time (APTT) and thrombin time (TT) assays. The purified G. filicina anticoagulant (GFA) inhibited the coagulation factor X (92%), factor II (82%), and factor VII (68%) of the coagulation cascade, and the molecular interaction (protein-polysaccharide) was highly enhanced in the presence of ATIII (antithrombin III). The dissociation constant of polysaccharide towards serine proteins decreased in the order of FXa (58.9 nM) >FIIa (74.6 nM) >FVII (109.3 nM). The low/less cytotoxicity of the polysaccharide benefits its use in the pharmaceutical industry; however, further studies that would help us to elucidate the mechanism of its activity are needed. 相似文献
4.
Won-Kyo Jung Yasantha Athukorala Young-Jae Lee Seon Heui Cha Chi-Ho Lee Thava Vasanthan Kwang-Sik Choi Sang-Ho Yoo Se-Kwon Kim You-Jin Jeon 《Journal of applied phycology》2007,19(5):425-430
Surface plasmon resonance is an important technique for studying molecular interactions and was used to investigate the molecular
interaction of anticoagulant sulfated polysaccharides purified from an enzymatic hydrolysate of the brown alga Ecklonia cava (ECA) with blood coagulation factors. In a direct binding assay, binding affinity between ECA/antithrombin III (ATIII) and
activated blood coagulation factors was in the order: factor VIIa (FVIIa) > factor Xa (FXa) > thrombin (FIIa); kinetic analysis
determined K
D values of ECA for FVIIa, FXa, and FIIa of 15.1, 45.0 and 65.0 nM, respectively. Therefore, ECA strongly and selectively (FVII,
FX, and FII) enhanced ATIII-mediated coagulation factor inhibition in both the extrinsic and common coagulation pathways.
This may contribute to its high anticoagulant activity in vitro. The low cytotoxicity of ECA to venous endothelial cell line
(ECV-304) also expands its value in future in vivo studies. However, to utilize it as a model for novel anticoagulant agents,
its possible interference with other anticoagulant mechanisms must be addressed. 相似文献
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6.
Antiproliferative activity of sulfated polysaccharide isolated from an enzymatic digest of Ecklonia cava on the U-937 cell line 总被引:1,自引:0,他引:1
Yasantha Athukorala Gin Nae Ahn Young-Heun Jee Gi-Young Kim Soo-Hyun Kim Jin-Hwan Ha Jung-Sook Kang Ki-Wan Lee You-Jin Jeon 《Journal of applied phycology》2009,21(3):307-314
A sulfated polysaccharide purified from a brown alga Ecklonia cava, having high anticoagulant activity was investigated for its antiproliferative effect on murine colon carcinoma (CT-26),
human leukemic monocyte lymphoma (U-937), human promyelocytic leukemia (HL-60), and mouse melanoma (B-16) cell lines. The
sulfated polysaccharide isolated and purified from an enzymatic extract of E. cava had a good selective tumor cell growth inhibition effect; its effect on HL-60 and U-937 was especially promising. The IC50 value for the sulfated polysaccharide from E. cava (ECSP) on U-937 was 43.9 μg mL−1. The presence of the sample in the cell culture media stimulated the induction of apoptosis, revealed by nuclear staining
with Hoechst 33342. The apoptosis induction was confirmed by the cell cycle analysis, while pronounced sub-G1 phase arrests
of 9.5% and 13.8% were also clearly observed when the cells were treated at 15 and 30 μg mL−1 of ECSP in the U-937 cell line, respectively. After a 24-h incubation period, ECSP dose-dependently enhanced the DNA fragmentation
on the U-937 cell line as observed in the agarose gel electrophoresis assay. To rule out the action mechanism of ECSP for
its anticancer activity, some western blot analyses were conducted with several antibodies (caspase-7, caspase-8, Bax, Bcl-xL,
and PARP) and ECSP had a clear effect on the caspase -7 and 8 which cleave protein substrates, including PARP, an inducer
of apoptosis responsible for DNA cleavage. Moreover, ECSP controlled the cellular transmembrane molecules like Bax and Bcl-xL.
Taken together, the above results demonstrate that the apoptosis for antiproliferative effect of ECSP was clearly induced
on U-937 cells. 相似文献
7.
Objectives
To determine how important governmental, social, and economic factors are in driving antibiotic resistance compared to the factors usually considered the main driving factors—antibiotic usage and levels of economic development.Design
A retrospective multivariate analysis of the variation of antibiotic resistance in Europe in terms of human antibiotic usage, private health care expenditure, tertiary education, the level of economic advancement (per capita GDP), and quality of governance (corruption). The model was estimated using a panel data set involving 7 common human bloodstream isolates and covering 28 European countries for the period 1998–2010.Results
Only 28% of the total variation in antibiotic resistance among countries is attributable to variation in antibiotic usage. If time effects are included the explanatory power increases to 33%. However when the control of corruption indicator is included as an additional variable, 63% of the total variation in antibiotic resistance is now explained by the regression. The complete multivariate regression only accomplishes an additional 7% in terms of goodness of fit, indicating that corruption is the main socioeconomic factor that explains antibiotic resistance. The income level of a country appeared to have no effect on resistance rates in the multivariate analysis. The estimated impact of corruption was statistically significant (p< 0.01). The coefficient indicates that an improvement of one unit in the corruption indicator is associated with a reduction in antibiotic resistance by approximately 0.7 units. The estimated coefficient of private health expenditure showed that one unit reduction is associated with a 0.2 unit decrease in antibiotic resistance.Conclusions
These findings support the hypothesis that poor governance and corruption contributes to levels of antibiotic resistance and correlate better than antibiotic usage volumes with resistance rates. We conclude that addressing corruption and improving governance will lead to a reduction in antibiotic resistance. 相似文献8.
Seung-Hong Lee Yasantha Athukorala Jung-Suck Lee You-Jin Jeon 《Journal of applied phycology》2008,20(6):1053-1059
In this study, hot water extracts of 22 red algal species were evaluated for their potential anticoagulant activities. The
extracts from eight species (Grateloupia elliptica, Sinkoraena lancifolia, Halymenia dilatata, Grateloupia lanceolata, Lomentaria catenata, Martensia denticulata,
Schizymenia dubyi, Chondrus crispus) showed potent activated partial thromboplastin time (APTT). Of these eight algae, the crude polysaccharide fraction (CpoF)
from the hot water extracts of L. catenata and S. dubyi showed the highest APTT activity. Lomentaria catenata and S. dubyi were selected and an enzymatic digestion process which could effectively separate a crude polysaccharide fraction with higher
yields from raw algae materials was applied. The 10 enzymes tested included five carbohydrases and five proteases. The Ultraflo
and Celluclast digests of L. catenata and the AMG digest of S. dubyi exhibited the most potent anticoagulant activity. Furthermore, in both species, the active compounds were mainly concentrated
in the >30 kDa fraction through ultrafiltration and showed strong APTT (>1000) and thrombin time (TT) >1000 activity. The
active compounds were shown to be sulfated galactans with a greater than 80% galactose content and an 0.22 ∼ 0.31 sulfate
to total sugar ratio. 相似文献
9.
Anticoagulant activity of marine green and brown algae collected from Jeju Island in Korea 总被引:1,自引:0,他引:1
Twenty-two algal species were evaluated for their potential anticoagulant activities. Hot water extracts from selected species, Codium fragile and Sargassum horneri showed high activated partial thromboplastin time (APTT). Ultraflo extract of C. fragile and S. horneri exhibited the most potent anticoagulant activity. Furthermore, in both algal species, active compounds were mainly concentrated in >30kDa faction. The crude polysaccharide fraction (>30kDa; CpoF) of C. fragile composed of approximately 80% carbohydrate and approximately 19% of protein; the crude polysaccharide fraction (>30kDa; CpoF) of S. horneri was composed of 97% of carbohydrate and approximately 2% of protein. Therefore, most probably the active compound, or compounds of the algal species were related to high molecular weight polysaccharide, or a complex form with carbohydrate and protein (proteoglycan). 相似文献
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