Production of aflatoxin by Aspergillus wentii Wehmer

1969 ◽  
Vol 15 (8) ◽  
pp. 895-898 ◽  
Author(s):  
H. W. Schroeder ◽  
M. Jacqueline Verrett
Keyword(s):  
Chick Embryo ◽  
Aflatoxin Production ◽  
Single Spore ◽  
Two Cultures ◽  
Additional Requirement ◽  
Field Corn ◽  
Parent Culture ◽  
Aspergillus Wentii ◽  
Aflatoxin B

Two cultures of Aspergillus wentii isolated from white field corn were tested through three consecutive single-spore generations for the ability to produce aflatoxins. Aflatoxin production by A. wentii was established. Production was low and variable. The variability was apparently not due to inhomogeneity in the parent culture. The identity of aflatoxin B1 was confirmed by chemical derivative tests and by the chick embryo bioassay. The ability to accumulate, as well as to produce, the aflatoxins is suggested as an additional requirement to qualify a fungus as an aflatoxin producer.

Control of Aspergillus flavus and aflatoxin production with spices in culture medium and rice

2013 ◽  
Vol 6 (1) ◽  
pp. 43-50 ◽  
Author(s):  
V. Aiko ◽  
A. Mehta
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Culture Broth ◽  
Minimum Inhibitory Concentrations ◽  
Food Grains ◽  
Star Anise ◽  
Aflatoxin B ◽  
Layer Chromatography

Cinnamon, cardamom, star anise and clove were studied for their effect on growth of Aspergillus flavus and aflatoxin B1 (AFB1) synthesis. The experiments were carried out in yeast extract sucrose culture broth as well as in rice supplemented with spices. AFB1 produced was analysed qualitatively and quantitatively using thin layer chromatography and high performance liquid chromatography, respectively. At a concentration of 10 mg/ml, cardamom and star anise did not exhibit any antifungal or anti-aflatoxigenic activity in culture broth, whereas cinnamon and clove inhibited A. flavus growth completely. The minimum inhibitory concentrations of cinnamon and clove were 4 and 2 mg/ml, respectively. Concentrations of cinnamon and clove below their minimum inhibitory concentrations showed enhanced fungal growth, while AFB1 synthesis was reduced. Clove inhibited the synthesis of AFB1 significantly up to 99% at concentrations ≥1.0 mg/ml. The spices also inhibited AFB1 synthesis in rice at 5 mg/g, although fungal growth was not inhibited. Clove and cinnamon inhibited AFB1 synthesis significantly up to 99 and 92%, respectively, and star anise and cardamom by 41 and 23%, respectively. The results of this study suggest the use of whole spices rather than their essential oils for controlling fungal and mycotoxin contamination in food grains.

Optimization of Chick Embryotoxicity Bioassay for Testing Toxicity Potential of Fungal Metabolites

1987 ◽  
Vol 70 (6) ◽  
pp. 1049-1055 ◽  
Author(s):  
Dan B Prelusky ◽  
Robert M G Hamilton ◽  
Brian C Foster ◽  
Locksley H Trenholm ◽  
Brian K Thompson
Keyword(s):  
Chick Embryo ◽  
Dose Response ◽  
Rapid Decrease ◽  
Fungal Metabolites ◽  
Toxic Compounds ◽  
Satisfactory Model ◽  
Toxicity Potential ◽  
Carrier Solvent ◽  
Testing Toxicity ◽  
Aflatoxin B

Abstract The optimization of a simple, sensitive procedure using a chick embryotoxicity screening test (CHEST) bioassay for detection of toxic compounds is presented. Dosing protocols of eggs, using several mycotoxins (aflatoxin B„ deoxynivalenol, T-2 toxin) and appropriate controls, were evaluated for embryonic sensitivity, overall practicality of the procedure, and consistency of results. It was found that both type of carrier solvent and volume injected could significantly affect overall embryonic mortality. The chick embryo was most sensitive to the effects of toxins and solvents after 1 or 2 days of incubation; a rapid decrease in response was observed as the age of the embryo at dosing increased. Following administration of the toxins just below the shell membrane by way of a small hole (<0.5 mm diameter) punched in the shell, a good dose-response (°/o mortality) could be obtained regardless of the site of injection (except directly into the yolk), although dosing via the air sac position resulted in a slightly better statistical outcome. Although some variations in calculated LD50 values were found among repeated assays, statistical analyses showed that the differences were not due to dosing protocol but to the variations in embryo sensitivities among batches of eggs. Thus, if standard reference toxins for comparison are run concurrently, the CHEST assay can prove to be a very satisfactory model, as well as having considerable flexibility to be adapted to the needs and resources of many laboratories.

scholarly journals Effect of Lactic Acid Bacteria Strains on the Growth and Aflatoxin Production Potential of Aspergillus parasiticus, and Their Ability to Bind Aflatoxin B1, Ochratoxin A, and Zearalenone in vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Cleide Oliveira de Almeida Møller ◽  
Luisa Freire ◽  
Roice Eliana Rosim ◽  
Larissa Pereira Margalho ◽  
Celso Fasura Balthazar ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Ochratoxin A ◽  
Aspergillus Parasiticus ◽  
Potassium Phosphate ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Binding Studies ◽  
Aflatoxin B

The increased consumption of plant-based foods has intensified the concern related to mycotoxin intoxication. This study aimed to investigate the effect of selected lactic acid bacteria (LAB) strains on the growth of Aspergillus parasiticus NRRL 2999 and its production of aflatoxin (AF). The ability of the heat-killed (100°C for 1 h) LAB strains to bind aflatoxin M1 (AFM1) in milk and aflatoxin B1 (AFB1), ochratoxin A (OTA), and zearalenone (ZEN) in potassium phosphate buffer (PPB) was also evaluated in vitro. Ten LAB strains were tested individually, by inoculating them simultaneously with the fungus or after incubation of the fungus for 24 or 48 h at 25°C. Double layer yeast extract sucrose (YES) agar, de Man Rogosa and Sharpe (MRS) agar, and YES broth were incubated for 7 days at 25°C to follow the development of the fungus. Levilactobacillus spp. 3QB398 and Levilactobacillus brevis 2QB422 strains were able to delay the growth of A. parasiticus in YES broth, even when these strains were inoculated 24 h after the fungus. The inhibitory effect of these LAB strains was confirmed by the reduction of fungus colony size, suggesting dominance of LAB by competition (a Lotka-Voltera effect). The production of AFB1 by A. parasiticus was inhibited when the fungus was inoculated simultaneously with Lactiplantibacillus plantarum 3QB361 or L. plantarum 3QB350. No AFB1 was found when Levilactobacillus spp. 2QB383 was present, even when the LAB was inoculated 48 h after the fungus. In binding studies, seven inactivated LAB strains were able to promote a reduction of at least 50% the level of AFB1, OTA, and ZEN. This reduction varied depending on the pH of the PPB. In milk, however, only two inactivated LAB strains were able to reduce AFM1, with a reduction of 33 and 45% for Levilactobacillus spp. 3QB398 (Levilactobacillus spp.) and L. brevis 2QB422, respectively. Nevertheless, these results clearly indicate the potential of using LAB for mycotoxin reduction.

SURVIVAL OF SINGLE-BASIDIOSPORE ISOLATES OF RHIZOCTONIA PRATICOLA AND RHIZOCTONIA SOLANI

1964 ◽  
Vol 10 (5) ◽  
pp. 739-746 ◽  
Author(s):  
George C. Papavizas
Keyword(s):  
Organic Matter ◽  
Rhizoctonia Solani ◽  
High Tolerance ◽  
Single Spore ◽  
Time Rate ◽  
Unamended Soil ◽  
Parent Culture ◽  
Oat Straw ◽  
Rhizoctonia Praticola ◽  
Rate Of Decline

Twenty randomly selected single-basidiospore isolates from each of Rhizoctonia praticola and R. solani differed considerably in their tolerance to CO2, competitive saprophytic activity, and ability to survive within precolonized substrate segments incubated in soils with or without pentachloronitrobenzene (PCNB) or oat straw. With a few exceptions, isolates possessing high saprophytic activity also possessed high tolerance to CO2 and high surviving ability in precolonized substrate. Several single-spore isolates of R. solani possessed higher ability for saprophytic survival in organic matter and lower CO2-sensitivity than their parent culture. Survival of single-basidiospore isolates in precolonized substrate segments was greater in unamended soil or soil amended with oat straw than in soil treated with PCNB. Mature oat straw reduced surviving ability of several isolates, whereas it increased surviving ability of others above that observed in unamended soil. The isolates whose surviving ability was increased by oat straw were mostly those possessing high saprophytic activity in unamended soil. Saprophytic activity and virulence of all isolates tested declined with time. Rate of decline of virulence was much more rapid for weak than strong saprophytes.

Partial characterization of the mode of action of benzoic acid on aflatoxin biosynthesis

1977 ◽  
Vol 23 (11) ◽  
pp. 1580-1584 ◽  
Author(s):  
Nduka Uraih ◽  
Timothy R. Cassity ◽  
John R. Chipley
Keyword(s):  
Benzoic Acid ◽  
Sodium Benzoate ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Aflatoxin Production ◽  
Acetyl Derivative ◽  
Cell Free Extract ◽  
Synthetic Media ◽  
Aflatoxin B ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Yellow Compound

Aflatoxin production by a toxigenic strain of Aspergillus flavus was greatly reduced by benzoic acid and sodium benzoate in synthetic media. The reduction was accompanied by the appearance of a yellow pigment. Spectral analyses partially characterized this pigment as closely related to an acetyl derivative of a versiconal-type compound. A cell-free extract prepared from A. flavus grown in synthetic media was active in converting this yellow compound into aflatoxin B1 in the presence of reduced nicotinamide adenine dinucleotide phosphate at 25 °C (pH 7.4). In the presence of benzoic acid and its salt or autoclaved cell-free extract, conversion of yellow compound to aflatoxin B1 was prevented. These results suggest that the yellow compound is an intermediate in the secondary metabolic cycle involved in aflatoxin B1 production. Benzoic acid, sodium benzoate, or autoclaving the cell-free extract appear to have respectively blocked or denatured an enzymatic step late in the biosynthetic pathway of aflatoxin B1.

Variability of uredial cultures of Puccinia graminis tritici derived from 'vegetative' axenic mycelium

1978 ◽  
Vol 56 (7) ◽  
pp. 855-861 ◽  
Author(s):  
G. J. Green ◽  
P. G. Williams ◽  
D. J. Maclean
Keyword(s):  
Growth Rate ◽  
Mitotic Division ◽  
Reduction Division ◽  
Puccinia Graminis ◽  
Diploid Nucleus ◽  
Two Cultures ◽  
Puccinia Graminis Tritici ◽  
Parent Culture ◽  
Axenic Cultures ◽  
Implant Technique

Two of 26 'vegetative' axenic cultures of Puccinia graminis tritici were induced to infect wheat by the epidermal stripping and mycelial implant technique. Only one of these two cultures produced urediospores and could be propagated on wheat. The urediospores obtained from implants had poor infectivity and there was a long incubation period. Single pustule isolates varied in growth rate, colour, virulence, sporulation, pustule type, and number of nuclei per spore. The uredial cultures comprised two groups: (1) one group with dikaryotic spores which resembled the parent culture race 126-Anz-6,7, Sydney University No. 334; (2) another group with monokaryotic spores which varied widely. The variability of the uredial cultures is interpreted as evidence that the diploid nucleus of the 'vegetative' axenic cultures originated by fusion of two haploid nuclei and divided in two ways: firstly, by a reduction division that produced two haploid nuclei and reconstituted a dikaryon similar to race 126-Anz-6,7, and secondly, by a mitotic division that produced diploids, variant aneuploids, and possibly mitotic recombinants.

Inhibitory effect of molybdenum and vanadium salts on aflatoxin B1 synthesis by Aspergillus flavus

1981 ◽  
Vol 27 (9) ◽  
pp. 962-967 ◽  
Author(s):  
C. J. Rabie ◽  
C. J. Meyer ◽  
Laetitia van Heerden ◽  
Annelie Lübben
Keyword(s):  
Trace Elements ◽  
Aspergillus Flavus ◽  
Basal Medium ◽  
Sodium Molybdate ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Complete Medium ◽  
Ammonium Heptamolybdate ◽  
Vanadium Salts ◽  
Aflatoxin B

The effects of the elements zinc, manganese, iron, copper, molybdenum, and vanadium, added in various salt forms, on mycelial weights and aflatoxin B1 accumulation in the mycelium of Aspergillus flavus were investigated in liquid shake cultures. Ammonium heptamolybdate, when added to a complete medium at concentrations of 50–100 mg/L, appreciably reduced aflatoxin B1 accumulation without affecting growth of the fungus. Sodium molybdate and sodium monovanadate also reduced aflatoxin B1 yields without affecting mycelial growth, but to a lesser extent.The addition of zinc sulphate stimulated aflatoxin B1 production in all media used. The influence of the other trace elements on aflatoxin production depended on the level of trace elements present in the basal medium. In general, manganese chloride had a stimulatory effect, whereas copper sulphate depressed yields.Mycelial levels of aflatoxin had peaked and then declined before mycelial dry weights had reached maximum.High yields of aflatoxin B1 were obtained in media having a final pH as low as pH 2.8.

scholarly journals Aspergillus flavus and Aflatoxin Contamination of Leguminous Trees of the Sonoran Desert in Arizona

2001 ◽  
Vol 91 (9) ◽  
pp. 913-919 ◽  
Author(s):  
María L. Boyd ◽  
Peter J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Sonoran Desert ◽  
Aflatoxin Production ◽  
Common Species ◽  
Aflatoxin Contamination ◽  
Leguminous Trees ◽  
Significant Growth ◽  
Tree Legumes ◽  
Aflatoxin B

Aspergillus spp. in section Flavi were frequently associated with desert tree legumes in uncultivated areas of the Sonoran Desert. Of 270 samples of debris and fruits of mesquite (Prosopis spp.), ironwood (Olneya tesota), acacia (Acacia spp.), and palo verde (Cercidium and Parkinsonia spp.), 87% were positive for A. flavus (S and L strains) and A. tamarii. A. flavus was the most common species (87%) among the 3,763 isolates examined. Mesquite pods were both the substrate from which A. flavus was recovered most frequently and the substrate from native habitats with the greatest aflatoxin content. In vitro, most desert legumes supported significant growth, reproduction, and aflatoxin production by A. flavus, with mesquite pods yielding 1 × 1010 propagules/g and 5,000 μg/kg of aflatoxin B1. Twenty percent of legume pods collected in the desert contained measurable quantities of aflatoxin, ranging from 1 to >2,500 μg/kg. Insect-damaged mesquite pods had significantly higher aflatoxin than intact pods. Legumes are apparently important reservoirs of aflatoxin-producing fungi and significant sources of aflatoxin contamination in the native Sonoran Desert habitats of Arizona.

Growth and aflatoxin production of an Italian strain of Aspergillus flavus: influence of ecological factors and nutritional substrates

2011 ◽  
Vol 4 (4) ◽  
pp. 425-432 ◽  
Author(s):  
P. Giorni ◽  
N. Magan ◽  
A. Pietri ◽  
P. Battilani
Keyword(s):  
Predictive Model ◽  
Aspergillus Flavus ◽  
Growth Rates ◽  
Fungal Growth ◽  
Ecological Factors ◽  
Quantitative Relationship ◽  
Aflatoxin Production ◽  
Optimum Temperature ◽  
Ripening Stages ◽  
Aflatoxin B

The aim of this study was to define quantitative relationships between temperature and water activity (aw), fungal growth and aflatoxin B1 (AFB1) production. A strain of Aspergillus flavus isolated from maize in north Italy, and previously tested and found positive for AFB1 production, was used for these experiments. The optimum temperature for AFB1 production was at 25 °C, slightly lower with respect to results obtained in other countries. 0.83 aw was the limit for growth of this strain of A. flavus after 60 days incubation at the optimum temperature. The solutes used to modify aw, glycerol and NaCl, influenced both growth and secondary metabolite production. Media modified with glycerol resulted in more AFB1 production when compared to the non-ionic solute NaCl added media. Maize based media, prepared with flour obtained from kernels at different ripening stages, only slightly influenced growth rates of A. flavus. The quantitative relationship obtained between fungal growth and AFB1 production in diverse temperature and aw levels were used to develop a valid predictive model for A. flavus presence and AFB1 production in the field.

Sign in / Sign up

Export Citation Format

Share Document