scholarly journals Antifungal Factor Produced by Pseudomonas fluorescens against an Endophytic Fungus

1970 ◽  
Vol 9 ◽  
pp. 65-71 ◽  
Author(s):  
Rajani Malla ◽  
Suprada Pokharel
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Fluorescens ◽  
Endophytic Fungus ◽  
Plant Growth Promoting Rhizobacteria ◽  
Inhibitory Effect ◽  
Piriformospora Indica ◽  
Antifungal Substance ◽  
Transmission Electron ◽  
Inhibitory Compound ◽  
Plant Growth Promoting

Growth characteristics of Piriformospora indica an endophytic fungus with plant growth promoting rhizobacteria in an aspergillus medium were studied. P. indica showed promotional effects with species of Azotobacter chroococcum, Azospirillum brasilensis, Bradyrhizobium spp., and inhibitory effect with Pseudomonas fluorescens. The biochemical and molecular level of inhibitory factor produced by P. fluorescence suggests that the antifungal substance was thermolabile and the protease test showed it to be protease resistant in nature. Dialysis test indicated that this substance had a molecular weight of more than 12,000 kDa. The inhibitory substance turns out to be 'fungistatic' as well as 'fungicidal' in nature. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies showed the cell wall in damaged form suggesting the high potency of this antifungal substance. The inhibitory compound produced by P. fluorescence was suspected to be pyoverdine, a kind of siderophore, an iron containing substance. Key words: Pseudomonas fluorescens; Piriformospora indica; siderophore; rhizobacteria; TEM; SEM DOI: 10.3126/njst.v9i0.3167 Nepal Journal of Science and Technology 9 (2008) 65-71

scholarly journals Plant growth-promoting rhizobacteria induced resistance in Jatropha curcas through phenyl propanoid metabolism against Rhizoctoniabataticola

2017 ◽  
Vol 9 (1) ◽  
pp. 121-128
Author(s):  
S. Kumar ◽  
M. Singh ◽  
Sushil Sharma
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Jatropha Curcas ◽  
Root Rot ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Total Phenols ◽  
Phenyl Propanoid ◽  
Plant Growth Promoting ◽  
Growth Promoting

The root rot disease in Jatropha curcas L. caused by Rhizoctonia. bataticola (Taub.) Butler has been recorded in causing 10-12 per cent mortality of 20-30 days old seedlings of Jatropha curcasin southern Haryana. The incidence of this disease has also been observed from other parts of Haryana too. Induction of systemic resistance in host plants through microbes and their bioactive metabolites are attaining popularity in modern agricultural practices. Studies on the plant growth-promoting rhizobacteria induced resistance in Jatropha curcas through phenyl propanoid metabolism against Rhizoctoniabataticola were undertaken at Chaudhary Charan Singh, Haryana Agricultural University, Regional Research Station, Bawal. Three plant growth-promoting rhizobacteria (PGPRs) viz., Pseudomonas maltophila, Pseudomonas fluorescens and Bacillus subtilis were evaluated for their potential to induce systemic resistance in Jatropha against root rot. The maximum increase of 97 per cent in total phenols, 120 per cent in peroxidase, 123 per cent in polyphenol oxidase, 101 per cent in phenylalanine ammonia lyase and 298 per cent in tyrosine ammonia lyase was detected in plants raised with Pseudomonas fluorescens+ Rhizoctoniaba-taticola inoculation in Jatropha curcas at 10 days post inoculation against control except total phenols where it was maximum (99%) at 30 DPI. There was slight or sharp decline in these parameters with age irrespective of inoculations. The pathogen challenged plants showed lower levels of total phenols and enzymes. The observations revealed that seed bacterization with Pseudomonas fluorescens results in accumulation of phenolics and battery of enzymes in response to pathogen infection and thereby induce resistance systemically.

scholarly journals Clusterin in Alzheimer’s Disease: An Amyloidogenic Inhibitor of Amyloid Formation

2021 ◽  
Author(s):  
Panagiotis M. Spatharas ◽  
Georgia I. Nasi ◽  
Paraskevi L. Tsiolaki ◽  
Marilena K. Theodoropoulou ◽  
Nikos C. Papandreou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fluorescence Emission ◽  
Inhibitory Effect ◽  
Fibril Formation ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Dynamics Simulations ◽  
Peptide Analogues

Abstract Background: Clusterin is a heterodimeric glycoprotein (α- and β-chain), which has been described as an extracellular molecular chaperone. In humans, clusterin is an amyloid associated protein, co-localizing with fibrillar deposits in Alzheimer’s disease. To clarify its implication in the disease, we provide evidence that clusterin has intrinsic amyloidogenic properties, which are intertwined with its inhibitory effect on amyloid-β fibril formation.Methods: Aggregation-prone regions of human clusterin were predicted by AMYLPRED. Synthetic peptide-analogues of each region underwent in vitro aggregation assays, namely, examination with transmission electron microscopy, X-Ray diffraction from oriented fibers, ATR FT-IR spectroscopy, and Congo Red birefringence assays. The same peptide-analogues were co-incubated with amyloid-β and their potential as inhibitors was tested with thioflavin T fluorescence emission measurements and transmission electron microscopy. Molecular dynamics simulations were performed to gain insight into the interaction between amyloid-β and the peptide-analogues.Results: Clusterin peptide-analogues form amyloid-like fibrils, as revealed by transmission electron microscopy. They can form fibers that give cross-β X-ray diffraction patterns and ATR FT-IR spectroscopy confirms the dominance of β-strand secondary structure. They also exhibit apple-green birefringence, when stained with Congo Red and examined between crossed polars of a polarizing light microscope. Furthermore, when amyloid-β is co-incubated with clusterin’s peptide analogues, it shows decreased thioflavin T fluorescence emission over time, while the formation of amyloid-β amyloid fibrils is diminished, as confirmed by transmission electron microscopy. The inhibitory effect of clusterin-peptide analogues on amyloid-β fibril formation was ascertained though molecular dynamics simulations. Conclusions: Clusterin has multiple aggregation-prone regions in its α-chain and these regions have a functional role in the inhibition of amyloid-β fibril formation.

scholarly journals Evaluation of Samarium Doped Hydroxyapatite, Ceramics for Medical Application: Antimicrobial Activity

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
C. S. Ciobanu ◽  
S. L. Iconaru ◽  
C. L. Popa ◽  
M. Motelica-Heino ◽  
D. Predoi
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Enterococcus Faecalis ◽  
Medical Application ◽  
Inhibitory Effect ◽  
Linear Increase ◽  
High Antibacterial Activity ◽  
Hydroxyapatite Ceramics ◽  
Transmission Electron

Samarium doped hydroxyapatite (Sm:HAp),Ca10-xSmx(PO4)6(OH)2(HAp), bionanoparticles with differentxSmhave been successfully synthesized by coprecipitation method. Detailed characterization of samarium doped hydroxyapatite nanoparticles (Sm:HAp-NPs) was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of samarium doped hydroxyapatite was assessed by cell viability. The antibacterial activity of the Sm:HAp-NPs was tested against Gram-negative bacteria (Pseudomonas aeruginosaandEscherichia coli) and Gram-positive bacteria (Enterococcus faecalisandStaphylococcus aureus). A linear increase of antimicrobial activity ofP. aeruginosahas been observed when concentrations of Sm:HAp-NPs in the samples withxSm=0.02were higher than 0.125 mg/mL. For Sm:HAp-NPs withxSm=0.05a significant increase of antibacterial activity onE. coliwas observed in the range 0.5–1 mg/mL. For low concentrations of Sm:HAp-NPs (xSm=0.05) from 0.031 to 0.125 mg/mL a high antibacterial activity onEnterococcus faecalishas been noticed. A growth of the inhibitory effect onS. aureuswas observed for all concentrations of Sm:HAp-NPs withxSm=0.02.

The use of microorganisms as bio-fertilizers in the cultivation of white lupine

2019 ◽  
Vol 17 (1) ◽  
pp. 813-822
Author(s):  
Hanna Sulewska ◽  
Karolina Ratajczak ◽  
Alicja Niewiadomska ◽  
Katarzyna Panasiewicz
Keyword(s):  
Pseudomonas Fluorescens ◽  
Field Experiments ◽  
Root Nodules ◽  
Control Object ◽  
Plant Growth Promoting Rhizobacteria ◽  
Dry Mass ◽  
Significant Strength ◽  
White Lupine ◽  
Plant Growth Promoting ◽  
The One

AbstractThe agricultural usability of bio-fertilizers, particularly including microbiological seed vaccines meet the recommendations for integrated protection/cultivation applicable in Poland. Combined vaccination seeds with Rhizobium bacteria together with endophitic bacteria from the group of Plant Growth Promoting Rhizobacteria (PGPR), increase the efficiency of biological nitrogen fixation and therefore stimulate the development and yielding of legume crops. This hypothesis was verified in a series of field experiments with white lupine conducted between 2016 and 2018 at Złotniki, Poland. The one-factor experiment consisted of different variants of inoculation including: seeds uninoculated, inoculated with nitragine, nitroflora, Pseudomonas fluorescens strain, Bacillus subtillis strain and seeds co-inoculated with Rhizobium from nitragine or nitroflora + Pseudomonas fluorescens, or + Bacillus subtillis. The experiment showed a positive response of white lupine to all tested seed vaccinations. The highest seed yield was found after seed inoculation with Rhizobium bacteria (from nitragine) and with co-inoculation Rhizobium with Pseudomonas fluorescens. The results indicated that plant height, the development of aboveground parts and roots as well as root nodules and the setting of pods and seeds on the plant increased significantly after seed co-inoculation of Rhizobium derived from the preparation of nitragine with Pseudomonas fluorescens, as compared to the control object without vaccination. A generally positive correlation was found between the number of root nodules, dry mass of nodules and yield, and an especially significant strength of this relationship was found in variant with co-inoculation Rhizobium with Pseudomonas fluorescens.

scholarly journals Sonochemical degradation of bisphenol A using persulfate activated by hematite nanoparticles (HNPs/PS)

2020 ◽  
Author(s):  
Mahboobeh Dehvari ◽  
Farshid Ghanbari ◽  
Mehdi Ahmadi
Keyword(s):  
Electron Microscopy ◽  
Bisphenol A ◽  
Oxygen Demand ◽  
Inhibitory Effect ◽  
Ultrasonic Power ◽  
Operational Parameters ◽  
Hematite Nanoparticles ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Mineralization Degree

Abstract In this study, hematite nanoparticles were used as persulfate activator for sonocatalytic degradation of bisphenol A (BPA). The physicochemical properties of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) analysis. The effect of different operational parameters such as pH, nanoparticle dosage, persulfate concentration, and ultrasonic power on catalytic activity were evaluated. The BPA degradation rate was improved when US irradiation was used simultaneously with HNPs for activating PS. According to the results, 98.94% of BPA (10 mg/L) was degraded within 15 min reaction time at 4 mM persulfate and 0.01 g/L α-Fe2O3 under ultrasonic irradiation of 250 W. The mineralization degree of BPA was determined by chemical oxygen demand (COD). 36.98% mineralization of BPA was achieved under optimum conditions. The quenching tests were done in the presence of different scavenger compounds. The results showed that both hydroxyl and sulfate radicals were reactive species in BPA degradation. According to the results of reusability test, the degradation efficiency was decreased to 86.34% indicating that HNPs can be recycled several times. Based on the results, all of the anions had the inhibitory effect on BPA degradation and most of the effect was related to hydrogen phosphate ions. The results showed that ultrasonic/hematite/ persulfate (US/HNPs/PS) process is an effective process for degradation of the organic pollutants.

scholarly journals Bacteriophage Prevalence in the Genus Azospirillum and Analysis of the First Genome Sequence of an Azospirillum brasilense Integrative Phage

2007 ◽  
Vol 74 (3) ◽  
pp. 861-874 ◽  
Author(s):  
Mickaël Boyer ◽  
Jacqueline Haurat ◽  
Sylvie Samain ◽  
Béatrice Segurens ◽  
Frédérick Gavory ◽  
...  
Keyword(s):  
Plant Growth Promoting Rhizobacteria ◽  
Complete Sequence ◽  
Pulsed Field Gel Electrophoresis ◽  
Double Stranded Dna ◽  
Transmission Electron ◽  
Circular Molecule ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Cd Genome ◽  
Phage Morphogenesis

ABSTRACT The prevalence of bacteriophages was investigated in 24 strains of four species of plant growth-promoting rhizobacteria belonging to the genus Azospirillum. Upon induction by mitomycin C, the release of phage particles was observed in 11 strains from three species. Transmission electron microscopy revealed two distinct sizes of particles, depending on the identity of the Azospirillum species, typical of the Siphoviridae family. Pulsed-field gel electrophoresis and hybridization experiments carried out on phage-encapsidated DNAs revealed that all phages isolated from A. lipoferum and A. doebereinerae strains had a size of about 10 kb whereas all phages isolated from A. brasilense strains displayed genome sizes ranging from 62 to 65 kb. Strong DNA hybridizing signals were shown for most phages hosted by the same species whereas no homology was found between phages harbored by different species. Moreover, the complete sequence of the A. brasilense Cd bacteriophage (ΦAb-Cd) genome was determined as a double-stranded DNA circular molecule of 62,337 pb that encodes 95 predicted proteins. Only 14 of the predicted proteins could be assigned functions, some of which were involved in DNA processing, phage morphogenesis, and bacterial lysis. In addition, the ΦAb-Cd complete genome was mapped as a prophage on a 570-kb replicon of strain A. brasilense Cd, and a region of 27.3 kb of ΦAb-Cd was found to be duplicated on the 130-kb pRhico plasmid previously sequenced from A. brasilense Sp7, the parental strain of A. brasilense Cd.

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