Chemical control of fungal growth and ochratoxin A production by Aspergillus isolated from Moroccan grapes

2018 ◽  
Vol 7 (2) ◽  
pp. 84-91
Author(s):  
Adil Laaziz ◽  
Souad Qjidaa ◽  
Yousra El Hammoudi ◽  
Abdelouahed Hajjaji ◽  
Amina Bouseta
Keyword(s):  
Ochratoxin A ◽  
Radial Growth ◽  
Culture Medium ◽  
Fungal Growth ◽  
Sublethal Concentration ◽  
Agar Culture ◽  
Total Inhibition ◽  
Yeast Autolysate ◽  
Germination And Growth ◽  
Czapek Yeast Autolysate Agar

The aim of this study was to evaluate the effect of three fungicides azoxystrobin (Ortiva), hexaconazole (Hexa) and pyrimethanil (Pyrus) for their ability to inhibit the radial growth and ochratoxin A (OTA) production by five ochratoxigenic strains of Aspergillus carbonarius and A. niger previously iso-lated from Moroccan grapes. Our results showed that, the addition of the fungicides to the Czapek Yeast Autolysate agar culture medium reduced the growth of the ochratoxigenic strains. Pyrimethanil caused total inhibition of spore germination and growth of the five strains, for all dose tested. Where-as hexaconazole totally inhibited the growth of 4 strains and gave growth for the MUCL 49227 strain (2.67 mm/day) at sublethal concentration. The reduction in radial growth was less marked for azoxystrobin, with growth rate varying between 0 and 6.37 mm/day depending on the strain and the azoxystrobin concentration. Analysis of variance showed that the effect of single factors (fungicides, concentration and strain) and their interactions on growth and OTA production were highly significant (P=0.000).These findings suggest that the use of tested fungicides have to potential for reduction in production of OTA.

Effect of five fungicides on growth and ochratoxin A production by two Aspergillus carbonarius and Aspergillus niger isolated from Moroccan grapes

2014 ◽  
Vol 4 (3) ◽  
pp. 118-126
Author(s):  
Souad Zouhair ◽  
Souad Qjidaa Qjidaa ◽  
Atar Selouane ◽  
Driss Bouya ◽  
Cony Decock ◽  
...  
Keyword(s):  
Growth Rate ◽  
Ochratoxin A ◽  
Fungal Growth ◽  
Inhibitory Effect ◽  
Aspergillus Carbonarius ◽  
Total Inhibition ◽  
Germination And Growth ◽  
Dose Dependent Increase ◽  
Dose Dependent

Five fungicides azoxystrobin (ortiva), benomyl (benlate), hexaconazole (hexa), pyrimethanil (scala) and thiabendazole (tectocal) were tested sepa-rately in vitro for their ability to inhibit the growth of two ochratoxigenic strains of A. niger and A. carbonarius previously isolated from grapes. All fungicides effectively reduced the growth rate of A. carbonarius and A. niger from 34 to 100% at the recommended dose (RD). Thiabendazole caused total inhibition of spore germination and growth of the two strains, regardless of the doses assayed. Benomyl completely inhibited growth of A. niger whereas for A. carbonarius, concentrations above 0.02xRD were required to prevent the growth. The inhibitory effect of hexaconazole, azoxystrobin and pyrime-thanil was dose-dependent. At sub-lethal concentrations of three fungicides, a dose-dependent increase in in ochratoxin A biosynthesis by two strains was observed. The use of fungicide should be checked for its ability to inhibit fungal growth as well as for their effect in terms of mycotoxins biosynthesis.

Effect of culture medium, temperature and incubation time on growth and ochratoxin A production by Aspergillus tubingensis and A. niger isolated from Moroccan vineyards

2015 ◽  
Vol 4 (6) ◽  
pp. 290-299
Author(s):  
Atar Selouane ◽  
Souad Qjidaa ◽  
Souad Zouhair ◽  
Ahmed Lebrihi ◽  
Driss Bouya ◽  
...  
Keyword(s):  
Incubation Time ◽  
Growth Rates ◽  
Radial Growth ◽  
Culture Medium ◽  
Culture Media ◽  
Fungal Growth ◽  
Maximal Growth ◽  
Aspergillus Tubingensis ◽  
Medium Temperature ◽  
Total Inhibition

  The effects of culture media (YES, CYA, SNM), temperature (10, 15, 20, 25, 30 and 37°C), incubation time (5, 10, 15 and 20 days) and their interactions on radial growth and OTA production by six A. tubingensis and two A. niger were studied. Growth rate increased as temperature increased, regardless of the culture media and isolates. Total inhibition of fungal growth of all strains on the three culture media was observed at 10°C. Mean growth rates calcu-lated for A. niger (2 isolates) and A. tubingensis (6 isolates) revealed that optimal temperatures for growth were observed at 30-37°C on CYA and YES media with maximal growth rates of 5.7 and 5.4 mm/day for A. niger and A. tubingensis cultivated in YES medium, respectively. Growth on SNM medium is generally slow, regardless the temperature and strain used. For both spe-cies, maximum means growth rates were determined at 37°C (3.7-3.8 mm/day). For OTA production, an incubation period of 5 days is sufficient to de-tect the OTA. Levels of this toxin are dependent on temperature, incubation time and strain. In the A. tubingensis specie, maximum of 0.710 μg/g of OTA was obtained after 10 days of incubation at 25°C on SNM medium while for A. niger, the maximum (0.36 μg/g) was obtained on CYA medium. The opti-mum conditions for OTA production are 25 °C/10 days. Analysis of variance showed that the effects of single factors (culture medium, temperature, in-cubation time and strain) and their interactions on growth and OTA produc-tion were highly significant (P=0.000).

Influence of pH and Incubation Time on Ochratoxin A Production by Aspergillus carbonarius in Culture Media

2005 ◽  
Vol 68 (7) ◽  
pp. 1435-1440 ◽  
Author(s):  
A. ESTEBAN ◽  
M. L. ABARCA ◽  
M. R. BRAGULAT ◽  
F. J. CABAÑES
Keyword(s):  
Ochratoxin A ◽  
Culture Media ◽  
Aspergillus Carbonarius ◽  
Yeast Autolysate ◽  
Initial Ph ◽  
Wide Ph Range ◽  
Ph Range ◽  
Incubation Temperatures ◽  
Influence Of Ph ◽  
Czapek Yeast Autolysate Agar

The effect of pH (2 to 10) and temperature (15 and 30°C) on growth and production of ochratoxin A (OTA) of six strains of Aspergillus carbonarius was studied in two culture media: Czapek yeast autolysate agar and yeast extract sucrose agar. Isolates were selected by their different source and different reported ability to produce OTA. Regardless of the initial pH or the temperature tested, Czapek yeast autolysate agar has been shown to be the best culture medium for OTA production by A. carbonarius. In this medium, OTA was produced from pH 2 to 10 at the two incubation temperatures tested. The results obtained show the ability of A. carbonarius to not only grow but also produce OTA over a wide pH range at high or low temperatures. This may help explain why this species is considered the main OTA source in some substrata.

Studies on the Fungal Pathogen of Dutch Elm Disease

1981 ◽  
Vol 39 ◽  
pp. 400-401
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo
Keyword(s):  
Fungal Pathogen ◽  
Fungal Growth ◽  
Polymyxin B ◽  
The United States ◽  
Dutch Elm Disease ◽  
Effective Control ◽  
Sabouraud Agar ◽  
Total Inhibition ◽  
Zones Of Inhibition ◽  
Control Plate

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.

Inhibition of Fungal Growth by Macerated Plant Tissues in a Closed Environment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476e-476
Author(s):  
Craig S. Charron ◽  
Catherine O. Chardonnet ◽  
Carl E. Sams
Keyword(s):  
Radial Growth ◽  
Fungal Pathogens ◽  
Solid Phase ◽  
Indian Mustard ◽  
Fungal Growth ◽  
Allyl Isothiocyanate ◽  
Pythium Ultimum ◽  
Alternative Methods ◽  
Gas Chromatography Mass Spectrometry ◽  
Clean Air

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.

In Vitro Removal of Ochratoxin A by Wine Lactic Acid Bacteria

2007 ◽  
Vol 70 (9) ◽  
pp. 2155-2160 ◽  
Author(s):  
VINCENZO DEL PRETE ◽  
HECTOR RODRIGUEZ ◽  
ALFONSO V. CARRASCOSA ◽  
BLANCA de las RIVAS ◽  
EMILIA GARCIA-MORUNO ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Ochratoxin A ◽  
High Performance ◽  
Culture Medium ◽  
Degradation Products ◽  
Cell Binding ◽  
A Cell ◽  
In Vitro Interaction

A study was carried out to determine the in vitro interaction between ochratoxin A (OTA) and wine lactic acid bacteria (LAB). Fifteen strains belonging to five relevant oenological LAB species were grown in liquid synthetic culture medium containing OTA. The portion of OTA removed during the bacterial growth was 8 to 28%. The OTA removed from the supernatants was partially recovered (31 to 57%) from the bacterial pellet. Cell-free extracts of three representative strains were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade OTA was studied. OTA was not degraded by cell-free extracts of wine LAB strains, and no degradation products of OTA were detected in the high-performance liquid chromatograms of the methanol extract of the bacterial pellet. On the basis of these results, we conclude that OTA removal by wine LAB is a cell-binding phenomenon. The chemistry and the molecular basis of OTA binding to wine LAB remains unknown.

scholarly journals Biotransformation of ferulic acid by the phytopathogenic fungi Colletotrichum acutatum and Lasiodiplodia theobromae

2016 ◽  
Vol 69 (1) ◽  
pp. 7835-7844 ◽  
Author(s):  
Manuel Alejandro Numpaque ◽  
Jesús Humberto Gil González ◽  
Diego Luis Durango Restrepo
Keyword(s):  
Ferulic Acid ◽  
Culture Medium ◽  
Microbial Transformation ◽  
Phytopathogenic Fungi ◽  
Colletotrichum Acutatum ◽  
Lasiodiplodia Theobromae ◽  
Natural Production ◽  
Total Inhibition ◽  
Detoxification Mechanism ◽  
Economical Alternative

The microbial transformation of ferulic acid (FA) offers a cleaner, more economical alternative for the natural production of flavorings and fragrances. In the present study, the biotransformation of FA using the filamentous phytopathogenic fungi Colletotrichum acutatum and Lasiodiplodia theobromae was researched. Initially, the toxicity of FA against both fungi was evaluated; the FA displayed a moderate toxicity (total inhibition at concentrations ≥ 2000 mg L-1) and apparently a detoxification mechanism was present. Afterwards, the microorganisms were incubated with the substrate at room conditions using a Czapek-Dox culture medium. The results demonstrated that the FA was mainly converted to 4-vinylguaiacol, reaching the highest abundance within the first 48 hours. To a lesser extent, acetovanillone, ethylguaiacol, and vanillin, among others, were produced. Interestingly, the compounds generated in the biotransformation of FA with C. acutatum and L. theobromae have been used as flavorings. Based on the identified metabolites, a possible metabolic pathway was proposed.

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.

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