scholarly journals Mycosynthesis of Silver Nanoparticles Using Screened Trichoderma Isolates and Their Antifungal Activity against Sclerotinia sclerotiorum

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1955 ◽  
Author(s):  
Ali Athafah Tomah ◽  
Iman Sabah Abd Alamer ◽  
Bin Li ◽  
Jing-Ze Zhang
Keyword(s):  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Sclerotinia Sclerotiorum ◽  
Direct Interaction ◽  
Hyphal Growth ◽  
Interaction Patterns ◽  
Fungal Cell ◽  
Trichoderma Species ◽  
Sclerotial Formation ◽  
Myceliogenic Germination

To control the disease caused by Sclerotinia sclerotiorum, a total of 15 isolates of the Trichoderma species was screened for the biosynthesis of silver nanoparticles (AgNPs). Among them, the highest yield occurred in the synthesis of AgNPs using a cell-free aqueous filtrate of T.virens HZA14 producing gliotoxin. The synthetic AgNPs were charactered by SEM, EDS, TEM, XRD, and FTIR. Electron microscopy studies revealed that the size of AgNPs ranged from 5–50 nm and had spherical and oval shapes with smooth surfaces. Prepared AgNPs interacted with protein, carbohydrate and heterocyclic compound molecules, and especially, interaction patterns of AgNPs with the gliotoxin molecule were proposed. The antifungal activity assays demonstrated that percentage inhibition of the prepared AgNPs was 100, 93.8 and 100% against hyphal growth, sclerotial formation, and myceliogenic germination of sclerotia at a concentration of 200 μg/mL, respectively. The direct interaction between nanoparticles and fungal cells, including AgNPs’ contact, accumulation, lamellar fragment production and micropore or fissure formation on fungal cell walls, was revealed by SEM and EDS. These will extend our understanding of the mechanisms of AgNPs’ action for preventing diversified fungal disease.

Effect of temperature during sclerotial formation, sclerotial dryness, and relative humidity on myceliogenic germination of sclerotia of Sclerotinia sclerotiorum

1998 ◽  
Vol 76 (3) ◽  
pp. 494-499 ◽  
Author(s):  
H C Huang ◽  
C Chang ◽  
G C Kozub
Keyword(s):  
Relative Humidity ◽  
Sclerotinia Sclerotiorum ◽  
Hyphal Growth ◽  
Effect Of Temperature ◽  
Limited Growth ◽  
Moist Sand ◽  
Sclerotial Formation ◽  
Seed Rot ◽  
Myceliogenic Germination ◽  
Exogenous Nutrients

A study was conducted to determine the effect of sclerotial dryness, temperature during sclerotia formation, and relative humiditiy during incubation on myceliogenic germination of sclerotia of two isolates of Sclerotinia sclerotiorum (Lib.) De Bary. In the absence of exogenous nutrients, sclerotia germinated more readily at 100% RH than at 95% RH or lower. Desiccation of sclerotia is an important factor affecting myceliogenic germination and hyphal growth. At high humidity, either in an atmosphere with 100% RH or on moist sand, desiccant-dried sclerotia germinated readily and produced vigorous hyphal growth that often developed into colonies. On the other hand, fresh, untreated sclerotia germinated less readily and produced limited growth of hyphae that rarely developed into colonies. There was generally no effect of temperature at which sclerotia formed on germination. The incidence of seed rot and seedling wilt of sunflower was significantly (p < 0.05) higher when desiccant-dried sclerotia were used as inoculum rather than fresh sclerotia.Key words: Sclerotinia sclerotionum, sclerotia, myceliogenic germination, sclerotinia wilt of sunflower, relative humidity.

scholarly journals Antifungal activity of silver nanoparticles during in-vitro culture of Stevia rebaudiana Bertoni

2019 ◽  
Author(s):  
Marco A. Ramírez-Mosqueda ◽  
Lino Sánchez-Segura ◽  
Sandra L. Hernández-Valladolid ◽  
Elohim Bello-Bello ◽  
Jericó J. Bello-Bello
Keyword(s):  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Cell Walls ◽  
Multiphoton Microscopy ◽  
Stevia Rebaudiana ◽  
Fungal Cell ◽  
Stevia Rebaudiana Bertoni ◽  
Transmission Electron ◽  
Ca 50

AbstractContamination by fungi and bacteria during the in-vitro propagation of plants leads to considerable losses of biological material and precludes phytosanitary certification. The anti-microbial effect of silver nanoparticles (AgNPs) may be an alternative for the eradication of in-vitro contaminants. This study evaluated the microbicidal activity of AgNPs on a recurrent fungus during the micropropagation of stevia (Stevia rebaudiana Bertoni). First, the fungus was isolated and identified at a molecular level by the sequencing and analysis of the ITS4/ITS5 rDNA region. The results of the phylogenetic analysis of various fungi species showed that the strain under study (16-166-H) belongs to the genus Sordaria and is 86.74% similar to S. tomento-alba (strain CBS 260.78). Subsequently, the inhibition of the growth of S. tomento-alba was tested under different concentrations of AgNPs (0, 25, 50, 100, and 200 mg L−1), observing that 50 and 100 mg L−1 achieve ca. 50% growth inhibition (IC50), while 200 mg L−1 produces a drastic inhibition. On the other hand, the shape and size of AgNPs was examined using transmission electron microscopy (TEM), and the transport and accumulation of AgNPs in S. tomento-alba cells were monitored through multiphoton microscopy. The morphological and fluorescence analyses showed that AgNPs display different sizes, with larger nanoparticles retained in fungal cell walls while smaller AgNPs penetrate into fungal cells. Probably, apoplastic and symplastic mechanisms involved in the accumulation and transport of AgNPs affect the metabolic processes of the fungus, thus inhibiting its growth. These results suggest that AgNPs possess antifungal activity and can be used in the eradication of contaminants during the in-vitro culture of plant species.

scholarly journals Inhibition of the Growth and Development of Sclerotinia sclerotiorum (Lib.) De Bary by Combining Azoxystrobin, Penicillium chrysogenum VKM F-4876d, and Bacillus Strains

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2520
Author(s):  
Vera V. Yaderets ◽  
Nataliya V. Karpova ◽  
Elena V. Glagoleva ◽  
Alexander I. Ovchinnikov ◽  
Kseniya S. Petrova ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Sclerotinia Sclerotiorum ◽  
Plant Pathogen ◽  
Penicillium Chrysogenum ◽  
Growth And Development ◽  
Crop Protection ◽  
Pathogenic Fungi ◽  
Fungal Cell ◽  
Bacillus Strains

Sclerotinia sclerotiorum (Lib.) de Bary is a plant pathogen with a wide host range, which causes significant yield and storage losses of edible roots and other plant products. Due to its ability to sclerotia formation, the efficient control of this pathogen is complicated. The study of five Bacillus strains (B. subtilis VKM B-3154D, VKM B-3155D, VKM B-3505D, VKM B-2998D, and B. amyloliquefaciens VKM B-3153D) showed their ability to produce polyene antibiotics suppressing the growth and development of plant pathogenic fungi. The maximum concentration of polyene compounds was revealed for B. subtilis VKM B-2998D. A high in vitro antifungal activity of a dry mycelium biomass (DMP) of Penicillium chrysogenum VKM F-4876D, B. subtilis VKM B-2998D, and their combination has been demonstrated in relation to S. sclerotiorum. A combined application of DMP (0.3 g/L) and azoxystrobin at low dosage (2.5 mg/L) showed a high suppressing activity towards S. sclerotiorum (100% growth inhibition) including inhibition of a sclerotia formation that may be useful for the development of efficient methods of crop protection against this plant pathogen. A high performance liquid chromatography (HPLC) analysis of DMP revealed the presence of mevastatin suggesting the mechanism of the DMP antifungal activity is based on the blocking of the ergosterol (the main component of fungal cell walls) biosynthesis. The results of the study provide a prerequisite to the development of biopreparations to control S. sclerotiorum, whose use may provide a reduction of concentrations of fungicides used in agriculture and the corresponding reduction of their negative xenobiotic impact on the environment and recovery of the ecological balance in the soil.

scholarly journals The newly synthesized thiazole derivatives as potential antifungal compounds against Candida albicans

2021 ◽  
Author(s):  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Gumieniczek ◽  
Maria Malm ◽  
Krzysztof Z. Łączkowski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Cell Membrane ◽  
Mode Of Action ◽  
Thiazole Derivatives ◽  
Fungal Cell ◽  
Erythrocyte Lysis ◽  
Low Cytotoxicity ◽  
High Antifungal Activity

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract

scholarly journals Biodirected Synthesis of Silver Nanoparticles Using Aqueous Honey Solutions and Evaluation of Their Antifungal Activity against Pathogenic Candida Spp.

2021 ◽  
Vol 22 (14) ◽  
pp. 7715
Author(s):  
Grzegorz Czernel ◽  
Dominika Bloch ◽  
Arkadiusz Matwijczuk ◽  
Jolanta Cieśla ◽  
Monika Kędzierska-Matysek ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Fungal Growth ◽  
Disc Diffusion ◽  
Candida Spp ◽  
Antifungal Effect ◽  
Synthesis Of Nanoparticles ◽  
Honey Solution ◽  
Diffusion Assay

Silver nanoparticles (AgNPs) were synthesized using aqueous honey solutions with a concentration of 2%, 10%, and 20%—AgNPs-H2, AgNPs-H10, and AgNPs-H20. The reaction was conducted at 35 °C and 70 °C. Additionally, nanoparticles obtained with the citrate method (AgNPs-C), while amphotericin B (AmB) and fluconazole were used as controls. The presence and physicochemical properties of AgNPs was affirmed by analyzing the sample with ultraviolet–visible (UV–Vis) and fluorescence spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS). The 20% honey solution caused an inhibition of the synthesis of nanoparticles at 35 °C. The antifungal activity of the AgNPs was evaluated using opportunistic human fungal pathogens Candida albicans and Candida parapsilosis. The antifungal effect was determined by the minimum inhibitory concentration (MIC) and disc diffusion assay. The highest activity in the MIC tests was observed in the AgNPs-H2 variant. AgNPs-H10 and AgNPs-H20 showed no activity or even stimulated fungal growth. The results of the Kirby–Bauer disc diffusion susceptibility test for C. parapsilosis strains indicated stronger antifungal activity of AgNPs-H than fluconazole. The study demonstrated that the antifungal activity of AgNPs is closely related to the concentration of honey used for the synthesis thereof.

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