scholarly journals Characterization of Antifungal Lipopeptide Biosurfactants Produced by Marine Bacterium Bacillus sp. CS30

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 199 ◽  
Author(s):  
Shimei Wu ◽  
Ge Liu ◽  
Shengnan Zhou ◽  
Zhenxia Sha ◽  
Chaomin Sun
Keyword(s):  
Antifungal Activity ◽  
High Performance ◽  
Magnaporthe Grisea ◽  
Antifungal Agents ◽  
Reversed Phase ◽  
Plant Diseases ◽  
Cold Seep ◽  
Bacillus Sp ◽  
Final Purification Step ◽  
Bacterium Bacillus

This study was initiated to screen for marine bacterial agents to biocontrol Magnaporthe grisea, a serious fungal pathogen of cereal crops. A bacterial strain, isolated from the cold seep in deep sea, exhibited strong growth inhibition against M. grisea, and the strain was identified and designated as Bacillus sp. CS30. The corresponding antifungal agents were purified by acidic precipitation, sequential methanol extraction, Sephadex LH-20 chromatography, and reversed phase high-performance liquid chromatography (RP-HPLC), and two antifungal peaks were obtained at the final purification step. After analysis by mass spectrometry (MS) and tandem MS, two purified antifungal agents were deduced to belong to the surfactin family, and designated as surfactin CS30-1 and surfactin CS30-2. Further investigation showed that although the antifungal activity of surfactin CS30-1 is higher than that of surfactin CS30-2, both of them induced the increased generation of reactive oxygen species (ROS) and caused serious damage to the cell wall and cytoplasm, thus leading to the cell death of M. grisea. Our results also show the differences of the antifungal activity and antifungal mechanism of the different surfactin homologs surfactin CS30-1 and surfactin CS30-2, and highlight them as potential promising agents to biocontrol plant diseases caused by M. grisea.

scholarly journals Antifungal Activity of Silver Ions and Nanoparticles on Phytopathogenic Fungi

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1037-1043 ◽  
Author(s):  
Young-Ki Jo ◽  
Byung H. Kim ◽  
Geunhwa Jung
Keyword(s):  
Antifungal Activity ◽  
Colony Formation ◽  
Magnaporthe Grisea ◽  
Silver Ions ◽  
Pathogenic Fungi ◽  
Chloride Ions ◽  
Plant Diseases ◽  
Plant Pathogenic Fungi ◽  
In Planta

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.

Isolation, identification, and antifungal activity of a macrolide antibiotic, oligomycin A, produced by Streptomyces libani

1999 ◽  
Vol 77 (6) ◽  
pp. 850-858 ◽  
Author(s):  
Beom Seok Kim ◽  
Surk Sik Moon ◽  
Byung Kook Hwang
Keyword(s):  
Antifungal Activity ◽  
Magnaporthe Grisea ◽  
Macrolide Antibiotic ◽  
Oryza Sativa L ◽  
Plant Diseases ◽  
Broth Culture ◽  
Molecular Formula ◽  
Leaf Blast ◽  
Cucumis Sativus L ◽  
Oligomycin A

The antibiotic As1A, strongly inhibitory to Phytophthora capsici Leonian in vitro and in vivo, was isolated from the broth culture of Streptomyces libani Baldacci & Grein using various chromatographic procedures. The molecular formula of the antibiotic As1A was deduced to be C45H74O11 (M+H, m/z 791.5307) by high resolution fast atom bombardment - mass spectroscopy. The analysis of 1H-NMR (nuclear magnetic resonance) and 13C-NMR spectroscopy, DEPT experiment, and two-dimensional NMR spectral data revealed that the antibiotic is a macrolide antibiotic having a 26-membered alpha, beta-unsaturated macrolactone ring with a conjugated diene fused to a bicyclic spiroketal. Based on the comparison of NMR data and other chemical properties, the antibiotic As1A turned out to have the same structure as oligomycin A. The antibiotic As1A showed a high level of inhibitory activity against Botrytis cinerea Pers.: Pers., Cladosporium cucumerinum Ellis & Arthur, Colletotrichum lagenarium (C.P. Robin) Berkhout, Magnaporthe grisea (Herb.) Barr, and P. capsici, ranging from 3 to 5 µg·mL-1 of MICs. However, no antimicrobial activity was found against yeasts and bacteria. In further evaluation under greenhouse conditions, developments of the Phytophthora disease, anthracnose, and leaf blast were markedly inhibited on pepper (Capsicum annuum L. cv. Hanbyul), cucumber (Cucumis sativus L. cv. Baekrokdadaki), and rice (Oryza sativa L. cv. Nakdong) plants by treatments with the antibiotic As1A, respectively. Control efficacies of the antibiotic As1A against these plant diseases were in general similar to those of metalaxyl, chlorothalonil, and tricyclazole. The antibiotic As1A did not show any phytotoxicity on pepper, cucumber, and rice plants even at 500 µg·mL-1.Key words: Streptomyces libani, oligomycin A, antifungal activity, plant disease control.

Synthesis and Antifungal Activities of Drimane-Amide Derivatives from Sclareol

2018 ◽  
Vol 21 (7) ◽  
pp. 501-509 ◽  
Author(s):  
Miaofeng Ma ◽  
Jili Feng ◽  
Dezhi Wang ◽  
Shu-Wei Chen ◽  
Hui Xu
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Antifungal Agents ◽  
Control Plant ◽  
Phytopathogenic Fungi ◽  
Plant Diseases ◽  
Economic Losses ◽  
Mycelium Growth ◽  
Amide Derivatives

Aim and Objective: Plant diseases are caused by fungal pathogens lead to severe economic losses in many agriculture crops. And the increasing resistance of many fungi to commonly used antifungal agents necessitates the discovery and development of new fungicides. So this study was focused on synthesizing novel skeleton compounds to effectively control plant diseases. Materials and Methods: A series of drimane-amide derivatives were designed, synthesized by aminolysis reaction of amine with intermediate sclareolide which was prepared from sclareol. The structures of all the synthesized compounds were confirmed using 1H NMR, 13C NMR, and HRMS (ESI) spectroscopic data. Their in vitro antifungal activity were preliminarily evaluated by using the mycelium growth rate method against five phytopathogenic fungi: Botrytis cinerea, Glomerella cingulata, Alternaria alternate, Alternaria brassicae, and Fusarium graminearum. Results: 23 target compounds were successfully obtained in yields of 52-95%. Compounds A2 and A3 displayed favorable inhibitory potency against B. cinerea, G. cingulata and A. brassicae with IC50 values ranging from 3.18 to 10.48 µg/mL. These two compounds displayed higher fungicidal activity than sclareol against all the tested phytopathogenic fungi, and were more effective than the positive control thiabendazole against A. alternate and A. brassicae. The structure-activity relationship studies of compounds A1-10 indicated that both the position and type of substituent on the phenyl ring had significant effects on antifungal activity. Conclusion: The drimane-amide derivatives A2 and A3 were the most promising derivatives and should be selected as new templates for the potential antifungal agents.

A primary study on nattokinase of bacterium Bacillus sp. isolated from nem chua

2015 ◽  
Vol 37 (1se) ◽  
Author(s):  
Nguyen Quynh Uyen ◽  
Hoang Thu Ha ◽  
Nguyen Hong Nhung ◽  
Phan Thi Ha ◽  
Nguyen Huynh Minh Quyen
Keyword(s):  
Primary Study ◽  
Bacillus Sp ◽  
Bacterium Bacillus

Development and Validation of A Reversed Phase-High Performance Liquid Chromatography Method for the Quantitative Estimation of Ramipril Drug Content from Formulated Dosage Form

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Raju Chandra ◽  
Manisha Pant ◽  
Harchan Singh ◽  
Deepak Kumar ◽  
Ashwani Sanghi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Active Ingredient ◽  
High Performance ◽  
Limit Of Detection ◽  
Quantitative Estimation ◽  
Reversed Phase ◽  
Uv Detector ◽  
Chromatography Method ◽  
Drug Content

A reliable and reproducible reversed-phase high performance liquid chromatography (RP-HPLC) was developed for the quantitative determination of Remipril drug content from marketed bulk tablets. The active ingredient of Remipril separation achieved with C18 column using the methanol water mobile phase in the ratio of 40:60 (v/v). The active ingredient of the drug content quantify with UV detector at 215 nm. The retention time of Remipril is 5.63 min. A good linearity relation (R2=0.999) was obtained between drug concentration and average peak areas. The limit of detection and limit of quantification of the instrument were calculated 0.03 and 0.09 µg/mL, respectively. The accuracy of the method validation was determined 102.72% by recoveries method.

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