scholarly journals Fungicidal effect of silver nanoparticles on toxigenic fungi in cocoa

2016 ◽  
Vol 51 (12) ◽  
pp. 1929-1936 ◽  
Author(s):  
Raquel Villamizar-Gallardo ◽  
Johann Faccelo Osma Cruz ◽  
Oscar Orlando Ortíz-Rodriguez
Keyword(s):  
Silver Nanoparticles ◽  
Fusarium Solani ◽  
Theobroma Cacao ◽  
Mycelial Growth ◽  
Culture Media ◽  
Fungal Growth ◽  
Inhibitory Effect ◽  
Plant Tissues ◽  
Inhibition Effect ◽  
Toxigenic Fungi

Abstract: The objective of this work was to evaluate the microbicidal effect of silver nanoparticles (AgNPs) on potentially toxigenic fungi affecting cocoa (Theobroma cacao) crops. These fungi, isolated from diseased cocoa pods, were characterized phenotypically and genotypically. The microbicidal effect was assessed by measuring radial mycelial growth, in synthetic culture media, and at different AgNP concentrations in plant tissues. The inhibition effect was monitored in Petri dishes, and changes in fungal structures were observed through scanning electron microscopy. Two potentially toxigenic fungi were highly prevalent: Aspergillus flavus and Fusarium solani. The inhibition assays, performed in liquid and solid synthetic culture media, showed that AgNPs did not significantly affect the growth of these fungi, even at the highest concentration (100 ppm). By contrast, they showed a positive inhibitory effect in plant tissues, especially in the cortex, when infected with A. flavus, in which an 80 ppm dose completely inhibited fungal growth. However, once fungi have managed to penetrate inside the pods, their growth is unavoidable, and AgNP effect is reduced. On F. solani, the studied nanomaterial only induced some texture and pigmentation changes. The microbicidal effect of chemically synthesized silver nanoparticles is greater in plant tissues than in culture media.

scholarly journals Selection of filamentous fungi that are resistant to the herbicides atrazine, glyphosate and pendimethalin

2021 ◽  
Vol 43 ◽  
pp. e51656
Author(s):  
Nara Priscila Barbosa Bravim ◽  
Anatércia Ferreira Alves ◽  
José Fábio França Orlanda ◽  
Patricia Barbosa Rodrigues Silva
Keyword(s):  
Filamentous Fungi ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Agricultural Soils ◽  
Culture Media ◽  
Fusarium Verticillioides ◽  
Fungal Growth ◽  
Relative Growth ◽  
Maximum Inhibition ◽  
Selection Of

The objective of the present study was to isolate fungi from agricultural soils and evaluate fungal growth in culture medium contaminated with atrazine, glyphosate and pendimethalin. Filamentous fungi were isolated from agricultural soils and cultured in a modified culture medium containing 0, 10, 20, 50, and 100 μg mL-1 atrazine, glyphosate and pendimethalin for 14 days at 28°C. The fungi that presented optimal and satisfactory growth were plated in Sabouraud culture medium with 4% dextrose and containing the herbicides at concentrations of 0, 10, 20, 50, and 100 μg mL-1 for seven days at 28°C. The mean mycelial growth values were submitted to analysis of variance and the Tukey test (p < 0.05%) for comparison and relative growth determination, and maximum inhibition rates were calculated. The isolated fungi Aspergillus fumigatus, Fusarium verticillioides and Penicillium citrinum were shown to be resistant to atrazine, glyphosate and pendimethalin. F. verticillioides showed higher mean mycelial growth in the culture media contaminated with atrazine and glyphosate than the other two fungi. In the culture medium contaminated with pendimethalin, F. verticillioides, and A. fumigatus presented the highest mean mycelial growth values.

scholarly journals In vitro inhibition of Fusarium solani by Trichoderma harzianum and biofertilizer

2021 ◽  
Vol 10 (3) ◽  
pp. e5210312994
Author(s):  
Paula Fernanda de Azevedo ◽  
Ana Carolina de Almeida ◽  
Rodrigo Domiciano Marques ◽  
Christiane Luciana da Costa ◽  
Anderson Roberto Benedetti ◽  
...  
Keyword(s):  
Trichoderma Harzianum ◽  
Spore Germination ◽  
Fusarium Solani ◽  
Mycelial Growth ◽  
Culture Media ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Sporulation Rate ◽  
Biological Fertilizer

Cassava root rot causes significant production losses. Difficulties of management, along with the lack of chemical fungicides officially registered by the Ministry of Agriculture, Livestock and Supply (MAPA), require alternative control methods. This study investigated the in vitro antagonistic activity of Trichoderma harzianum as well as a biological fertilizer MICROGEO® on Fusarium solani. The phytophatogenic strains of F. solani, called F1 and F2 were isolated from rotted cassava tubers and T. harzianum, strain ESALQ 1306, from a biological fungicide. Continuous liquid composting of bovine ruminal content, water and MICROGEO® produced the biological fertilizer. Dual culture method was used at the bioassay with T. harzianum. Sterilized (St) and unsterilized (USt) biological fertilizer were tested in different concentrations (% v/v) diluted in the culture media. Colony diameters were measured daily in order to establish the mycelial growth velocity index, inhibition percentage, aside from the sporulation rate and spore germination percentage. The mycelial growth of F. solani isolates was interrupted after hyphae encounter with T. harzianum, due to the occurrence of mycoparasitism, but without influence on the sporulation rate. Sterilized biological fertilizer induced no biocontrol, whereas the unsterilized product (concentration 2.5%) inhibited approximately 64% and 85% of the mycelial growth of isolates F1 and F2, respectively. Moreover, spore germination declined with increasing concentration. In conclusion, T. harzianum and the unsterilized biofertilizer showed in vitro antagonistic activity on F. solani.

scholarly journals Effect of Culture Media, Temperature and pH on Growth of Sphaeropsis Tumefaciens, Hedges

1969 ◽  
Vol 69 (3) ◽  
pp. 391-396
Author(s):  
Sol D. Rodríguez ◽  
Rocío Rodríguez ◽  
Pedro L. Meléndez
Keyword(s):  
Mycelial Growth ◽  
Culture Media ◽  
Fungal Growth ◽  
Effective Medium ◽  
Fruit Peel

Of twenty-eight culture media evaluated for S. tumefaciens growth and sporulation, Czapek solution agar was the most effective medium for the induction of sporulation. Optimum mycelial growth was observed on citron fruit peel agar, V-8, and citron branch agar 3 days after inoculation at 28° C. However, most media were effective in stimulating mycelial growth after 7 days of incubation. Optimum fungal growth was obtained at 30° to 35° C and at pH 4.0.

scholarly journals Radiation Synthesis of Silver Nanoparticles/Chitosan for Controlling Leaf Fall Disease on Rubber Trees Causing by Corynespora cassiicola

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Le Thi An Nhien ◽  
Nguyen Duc Luong ◽  
Le Thi Thuy Tien ◽  
Le Quang Luan
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Fungal Growth ◽  
Corynespora Cassiicola ◽  
Sem Images ◽  
Inhibition Effect ◽  
Foliar Treatment ◽  
Inhibitory Efficiency

Silver nanoparticles (AgNPs) were successfully prepared by γ-rays irradiation of solution containing 1.0–10 mM of silver nitrate and 1% chitosan. The optical characteristics and particles sizes of AuNPs were determined by UV-Vis spectra and TEM images, respectively. The size of AgNPs increased by the increase of silver concentration or the decrease of chitosan molecular weight in irradiated solution. The in vitro test showed that AgNPs inhibited the growth of Corynespora cassiicola on rubber-leaf extract media with the inhibitory efficiency of 52.1–100% by treatment of AgNPs with particle size from 15 to 5 nm, respectively. In addition, antifungal activity was found to reach ~100% by the addition of 90 ppm AgNPs. The in vivo foliar treatment of AgNPs on 9-month-old rubber plants showed that the treatment with 2.5–12.5 ppm AgNPs on tested plants after inoculation by spraying with C. cassiicola spores enhanced the rate of non-disease-infected plants from 6.0 to 93.3%, respectively, compared to the untreated control. The inhibition effect of AgNPs on fungal growth of C. cassiicola mycelial was also elucidated via SEM images. The AgNPs/chitosan synthesized by γ-irradiation is potentially promising to use as a fungicidal product for treating C. cassiicola, a serious pathogen fungus on rubber trees.

A Study of Aflatoxin Production by Aspergillus Flavus Growing on Wallboard

1997 ◽  
Vol 2 (4) ◽  
pp. 36-42 ◽  
Author(s):  
Carol Y. Rao ◽  
Richard C. Fink ◽  
Linda B. Wolfe ◽  
Daniel F. Liberman ◽  
Harriet A. Burge
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Building Materials ◽  
Culture Media ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Culture Collection ◽  
Indoor Environments ◽  
Toxigenic Fungi ◽  
Aflatoxin Concentration

The potential for exposure to mycotoxins in indoor environments is of increasing concern. In order to evaluate the potential for mycotoxin production by toxigenic fungi growing on water-damaged building materials, two aflatoxin producing strains of Aspergillus flavus (American Type Culture Collection 16875 and 15547) were inoculated onto culture media, plain wallboard, and vinyl wallpapered wallboard (cellulose-based and wheat-based wallpaper paste) and incubated at high relative humidity and room temperature for up to 16 weeks. Each sample was extracted with 60% methanol and aflatoxins in the crude extract were collected by immunoaffinity chromatography and quantified by fluorometry. Analysis by high performance liquid chromatography was performed for confirmation. Varying degrees of fungal growth were evident on all tested substrate types. Up to 4800 ppb of aflatoxin was detected when strain ATCC 16875 was grown on potato dextrose agar. However, when inoculation was standardized to minimize initial aflatoxin concentration in the inoculum, aflatoxin production was not detected on any wallboard sample under any of the incubation conditions provided. The presence of a toxigenic fungal strain on an indoor substrate does not necessarily indicate that the fungus is producing mycotoxins and our data provide evidence that wet wallboard is unlikely to provide appropriate conditions for aflatoxin production.

scholarly journals Effect of powdered spice treatments on mycelial growth, sporulation and production of aflatoxins by toxigenic fungi

2004 ◽  
Vol 28 (4) ◽  
pp. 856-862 ◽  
Author(s):  
Sára Maria Chalfoun ◽  
Marcelo Cláudio Pereira ◽  
Mario Lúcio V. Resende ◽  
Caroline Lima Angélico ◽  
Rozane Aparecida da Silva
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Flavus ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Culture Media ◽  
The Other ◽  
Toxigenic Fungi ◽  
Order Promising ◽  
Fungistatic Effect

The effect of ten powdered spice plants was evaluated at the concentration of 1, 2, 3 and 4% to observe the mycelial growth and sporulation of Aspergillus niger and Eurotium repens. The spices were added to the culture media PDA and CYA20S. Clove completely inhibited the mycelial growth of the tested fungi. The other spices: cinnamon, garlic, thyme, mint, anis, oregano and onion were, in a decreasing order, promising antifungals. Bay leaf and basil did not show a pronounced fungistatic effect. The antitoxigenic potential of the spices was tested against one aflatoxin-producing strain of AspergiIIus flavus. The spices were tested at the same concentrations previously mentioned and were added to the culture medium YES, appropriate for the production of those metabolites. Clove completely inhibited the mycelial growth of Aspergillus flavus. Cinnamon and anis totally inhibited the production of Bl and B2 aflatoxin. Both bay leaf and basil inhibited the synthesis of aflatoxin starting from the concentration of 2%. The other spices did not have a pronounced antiaflatoxigenic effect.

Inhibitory Effect of Beta-Ionone on Growth and Aflatoxin Production by Aspergillus parasiticus on Peanuts1

1986 ◽  
Vol 49 (7) ◽  
pp. 515-518 ◽  
Author(s):  
CHENG-I WEI ◽  
HSIOUKUN TAN ◽  
SAMUEL Y. FERNANDO ◽  
NAN-JING KO
Keyword(s):  
Sodium Hypochlorite ◽  
Direct Contact ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Distilled Water ◽  
Antifungal Compounds ◽  
Treatment Conditions

The volatile ketone (β-ionone showed a dose-related inhibition of fungal growth and aflatoxin production on peanuts after they were soaked in distilled water for 25 or 50 min, inoculated with spores, and incubated at 28°C for up to 2 weeks. For example, aflatoxin B1 (AFB1) production after 1 week of incubation was reduced to less than 11.0 and 6.7% of the control when 2.5 or 5 ml of (β-ionone/100 g of peanuts, respectively, was added to water-soaked (25 min) peanuts. For AFG1, production was reduced to 4.7 (2.5 ml) or 3.3% (5.0 ml) under the same treatment conditions. Unlike controls or those treated with less than 0.1 ml of β-ionone, peanuts treated with more than 0.25 ml of β-ionone had only sparse mycelial growth and supported only limited sporulation. The mycelia, after being transferred to fresh Mycological or Fluorescent Agar plates, still had the ability to form normal colonies and produce aflatoxins. This temporary limitation of fungal growth was also noticed for those Aspergillus cultures on Mycological Agar that had been treated with (β-ionone either by direct contact or volatile bioassay procedures. The fungus was still able to grow of Fluorescent Agar even after the infected peanuts were treated with sodium hypochlorite for 15 or 30 min, indicating that mycelial penetration into peanut tissues occurs. This may confer protection from the action of various antifungal compounds. This observtion is further supported by microscopic detection of mycelial fragments in peanut tissues.

scholarly journals Antifungal Activity of Copper, Zinc and Potassium Compounds on Mycelial Growth and Conidial Germination of Fusarium solani f. sp. piperis

2019 ◽  
pp. 1-11 ◽  
Author(s):  
Renata Aparecida Ahnert Dos Santos ◽  
Verônica D’Addazio ◽  
João Vitor Garcia Silva ◽  
Antelmo Ralph Falqueto ◽  
Marcelo Barreto da Silva ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fusarium Solani ◽  
Mycelial Growth ◽  
Fungal Growth ◽  
Conidial Germination ◽  
Piper Nigrum ◽  
Economic Damage ◽  
Potato Dextrose Agar Medium ◽  
Copper Zinc

Fusariosis is a disease that causes economic damage to black pepper (Piper nigrum L.) producers. Despite being a major disease, there is no record of efficient chemical control. Thus, the objective was to evaluate the antifungal activity of copper, zinc and potassium compounds in mycelial growth and conidial germination of Fusarium solani f. sp. piperis in vitro. For inoculation in PDA (Potato Dextrose Agar) medium, 7 mm discs from the pure culture were transferred to Petri dishes. The plates were incubated at 25ºC in a biochemical oxygen demand (BOD) chamber, with photoperiod of 12 h, for 15 days. Micronutrients were supplied as sulfates, CuSO4 (copper sulfate) and ZnSO4 (zinc sulfate), at concentrations of 1, 5, 10, 15 and 20 mmol/L. Potassium macronutrient (K) was supplied as KCl (potassium chloride) at concentrations of 30, 60, 90,120 and 150 mmol/L. The experiment was performed using a completely randomized design with 6 treatments and ten replications. CuSO4 showed fungicidal effect at concentrations of 10, 15 and 20 mmol/L. For ZnSO4 mycelial growth was completely inhibited at concentrations of 15 and 20 mmol/L. There was no inhibition or reduction of fungal growth in the presence of K. Copper and zinc at minimal concentrations were efficient in controlling mycelial growth and inhibition of spore germination of F. solani f. sp. piperis. In contrast, potassium did not exert fungicidal or fungistatic effect on the fungus.

scholarly journals Diffusible Compounds Produced by Hanseniaspora osmophila and Gluconobacter cerinus Help to Control the Causal Agents of Gray Rot and Summer Bunch Rot of Table Grapes

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 664
Author(s):  
Matías Olivera ◽  
Ninoska Delgado ◽  
Fabiola Cádiz ◽  
Natalia Riquelme ◽  
Iván Montenegro ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Biocontrol Agents ◽  
Environmental Cost ◽  
Antifungal Compounds ◽  
Table Grapes ◽  
Dual Cultures ◽  
Bunch Rot ◽  
Direct Bioautography

Gray and summer bunch rot are important diseases of table grapes due to the high economic and environmental cost of their control with synthetic fungicides. The ability to produce antifungal compounds against the causal agents Botrytis, Aspergillus, Penicillium, and Rhizopus of two microorganisms isolated from table grapes and identified as Hanseniaspora osmophila and Gluconobacter cerinus was evaluated. In dual cultures, both biocontrol agents (together and separately) inhibited in vitro mycelial growth of these pathogens. To identify the compounds responsible for the inhibitory effect, extractions were carried out with organic solvents from biocontrol agents separately. Through dual cultures with pathogens and pure extracts, only the hexane extract from H. osmophila showed an inhibitory effect against Botrytis cinerea. To further identify these compounds, the direct bioautography technique was used. This technique made it possible to determine the band displaying antifungal activity at Rf = 0.05–0.2. The compounds present in this band were identified by GC-MS and compared to the NIST library. The most abundant compounds, not previously reported, corresponded to alkanes, ketones, alcohols, and terpenoids. H. osmophila and G. cerinus have the potential to control the causal agents of gray and summer bunch rot of table grapes.

scholarly journals Application of Furcellaran Nanocomposite Film as Packaging of Cheese

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1428
Author(s):  
Agnieszka Pluta-Kubica ◽  
Ewelina Jamróz ◽  
Gohar Khachatryan ◽  
Adam Florkiewicz ◽  
Pavel Kopel
Keyword(s):  
Silver Nanoparticles ◽  
Nanocomposite Film ◽  
Microbiological Quality ◽  
Inhibitory Effect ◽  
Quality Properties ◽  
In Situ Method ◽  
And Migration ◽  
Total Bacteria

There is a serious need to develop and test new biodegradable packaging which could at least partially replace petroleum-based materials. Therefore, the objective of this work was to examine the influence of the recently developed furcellaran nanocomposite film with silver nanoparticles (obtained by an in situ method) on the quality properties of two cheese varieties: a rennet-curd (gouda) and an acid-curd (quark) cheese. The water content, physicochemical properties, microbiological and organoleptic quality of cheese, and migration of silver nanoparticles were examined. Both the number of Lactococcus and total bacteria count did not differ during storage of gouda regardless of the packaging applied. The number of Lactococcus decreased in analogous quark samples. The use of the film slowed down and inhibited the growth of yeast in gouda and quark, respectively. An inhibitory effect of this film on mold count was also observed; however, only regarding gouda. The level of silver migration was found to be lower in quark than in gouda. The film improved the microbiological quality of cheeses during storage. Consequently, it is worth continuing research for the improvement of this film in order to enable its use in everyday life.

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