Effect of time and temperature on ochratoxin A production by Aspergillus ochraceus

1973 ◽  
Vol 19 (10) ◽  
pp. 1259-1263 ◽  
Author(s):  
Gerald A. Sansing ◽  
Norman D. Davis ◽  
Urban L. Diener
Keyword(s):  
Ochratoxin A ◽  
Nutrient Solution ◽  
Yeast Extract ◽  
Aspergillus Ochraceus ◽  
Shake Culture ◽  
High Ph ◽  
Stationary Culture ◽  
Ph Values

Peak ochratoxin A production by Aspergillus ochraceus occurred at 25C after 10 and 12 days incubation on a nutrient solution of 4% sucrose and 2% yeast extract. Optimal mycelial production was at 20 and 25C at 6, 8, and 10 days incubation. High pH values of 7.6–8.2 coincided with high ochratoxin production at 25C at 8-14 days incubation. Maximal amounts of ochratoxin A were produced by A. ochraceus in 25 ml of medium/125-ml flask and 75 ml of medium/500-ml flask at 25C in stationary culture in 8 days. Ochratoxin A was not produced in this medium in shake culture.

Inhibition of Production of Cyclopiazonic Acid and Ochratoxin A by the Fungicide Iprodione‡

1997 ◽  
Vol 60 (7) ◽  
pp. 849-852 ◽  
Author(s):  
CÉLESTIN MUNIMBAZI ◽  
JYOTI SAXENA ◽  
WEI-YUN J. TSAI ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Ochratoxin A ◽  
Incubation Period ◽  
Aspergillus Flavus ◽  
Growth Medium ◽  
Yeast Extract ◽  
Active Ingredient ◽  
Cyclopiazonic Acid ◽  
Aspergillus Ochraceus ◽  
Growth Media ◽  
Yeast Extract Sucrose

Aspergillus flavus NRRL 1290 and Aspergillus ochraceus NRRL 3174 were grown on a glucose-salts medium and yeast extract-sucrose broth containing the fungicide iprodione at concentrations of 0, 1,3,5, 10, 15, and 20 μg of active ingredient per ml of growth medium. Cultures were analyzed for cyclopiazonic acid, ochratoxin A, and mycelium production after 4,7, 10, 14, and 21 days of incubation at 25°C. Increasing concentrations of iprodione in the growth media resulted in greater reduction of cyclopiazonic acid, ochratoxin A, and mycelium production at the end of each incubation period. More than 50% reduction of cyclopiazonic acid, ochratoxin A, and mycelium production was observed when iprodione was added to growth media at a concentration of 5 μg/ml of medium. Higher concentrations of iprodione (10 to 20 μg/ml of growth medium) inhibited the production of cyclopiazonic acid and mycelium by A. flavus NRRL 1290 almost completely, but not the production of ochratoxin A and mycelium by A. ochraceus NRRL 3174.

scholarly journals Ochratoxin A 'in vitro' biosynthesis by the Aspergillus ochraceus E'G isolate

2009 ◽  
pp. 69-77 ◽  
Author(s):  
Aleksandra Bocarov-Stancic ◽  
Aleksandra Miljkovic ◽  
Radmila Resanovic ◽  
Ksenija Nesic ◽  
Vesna Jacevic ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Yeast Extract ◽  
Toxin Production ◽  
Aspergillus Ochraceus ◽  
Submerged Cultivation ◽  
Wheat Grain ◽  
Liquid Media ◽  
Potato Dextrose Broth ◽  
Solid Substrates

This paper deals with the biosynthetic capacity for ochratoxin A (OTA) production by Aspergillus ochraceus E'G isolate derived from A. ochraceus CBS 108.08 strain, during 2007. Preliminary analysis of fungal potential for the production of OTA were performed according to the modified method of Filtenborg et al. (1983). Toxin production was tested in the following liquid media: (i) glucose-peptone-yeast extract broth (GPY - pH 5.6), (ii) potato-dextrose broth (PDB - pH 6.9), (iii) yeast extract-sucrose broth (YES - pH 6.5), and (iv) YES broth supplemented with 0.23 mg/l ZnSO4 x 5 H2O (YESZn - pH 6.5) after stationary and submerged cultivation. Dynamics of OTA biosynthesis was tested after the cultivation of A. ochraceus E'G on natural solid substrates, such as wet sterilized rice, corn and wheat grain. Cultivations were performed during different time periods (ranging from four days to few weeks) at different temperatures (ranging from 21?C to 30?C). The presence of OTA was determined as follows: (i) in liquid media according to the method of Balzer et al. (1978) modified by Bocarov-Stancic et al. (2003), and (ii) in the solid substrates according to the Serbian official methods for sampling and analyzing of fodder (Official Gazette of SFRY, No. 15/87). After the cultivation of A. ochraceus E'G isolate in liquid media, the highest yield of OTA (6.4 mg/l) was obtained after submerged cultivation in PDB (4 days, 128 rpm, 21-23?C). In the case of cultivation on solid substrates, the highest amount of OTA (800.0 mg/kg of dry matter) was recorded after several week long cultivation on wheat grain at 30?1?C.

Impact of climate and bulking materials on characteristics of compost from ecological toilets

2012 ◽  
Vol 2 (2) ◽  
pp. 79-86 ◽  
Author(s):  
James W. McKinley ◽  
Rebecca E. Parzen ◽  
Álvaro Mercado Guzmán
Keyword(s):  
Low Carbon ◽  
Pathogen Inactivation ◽  
High Ph ◽  
Moisture Contents ◽  
Urine Diversion ◽  
Ph Values ◽  
Dominant Process ◽  
Nitrogen Ratio ◽  
Storage Times ◽  
Carbon Concentrations

Urine-diversion dehydration toilets (UDDT) are common throughout the developing world, and the toilet product is widely used as compost. There is no comprehensive research to date that characterizes the compost to determine its quality, extent of pathogen inactivation, and the effects of climate and bulking materials on the compost. Compost was collected from 45 UDDT in Bolivia and analyzed for physical, chemical, and biological parameters. Eighty percent and 56% of samples did not meet acceptable compost guidelines for moisture content and pH, respectively, indicating desiccation was the dominant process in UDDT. Bulking materials significantly impacted compost characteristics in terms of pH, carbon, carbon-to-nitrogen ratio, and carbon stability (P < 0.05). Composts with ash exhibited, on average, low carbon concentrations (4.9%) and high pH values (9.7), which can be harmful to plants and composting microorganisms. Composts with sawdust exhibited, on average, high carbon concentrations (40.0%) and carbon-to-nitrogen ratios (31.0). Climate had no significant impact on chemical characteristics, however composts from humid regions had significantly higher moisture contents (34.4%) than those from arid climates (24.8%) (P < 0.05). Viable Ascaris lumbricoides ova were identified in 31% of samples, including samples with high pH, low moisture contents, and long storage times.

Bioproduction of ochratoxin A and penicillic acid by members of the Aspergillus ochraceus group

1972 ◽  
Vol 18 (5) ◽  
pp. 631-636 ◽  
Author(s):  
Alex Ciegler
Keyword(s):  
Quantitative Analysis ◽  
Low Temperature ◽  
Ochratoxin A ◽  
Acid Synthesis ◽  
Aspergillus Ochraceus ◽  
Cereal Grains ◽  
Liquid Media ◽  
Penicillic Acid ◽  
Group A ◽  
Fluorescent Derivatives

Various strains of species belonging to the Aspergillus ochraceus group (A. ochraceus, A. sclerotiorum, A. alliaceus, A. ostianus, A. melleus, and A. sulphureus) can produce two mycotoxins, ochratoxin A and penicillic acid, on liquid media and in cereal grains. The quantity of each toxin produced is influenced by temperature; low temperature (10 and 20C) favor penicillic acid synthesis and higher (28C), ochratoxin A production. Generally penicillic acid is produced in yields about one to three magnitudes greater than ochratoxin A. A simple fluorodensitometric method for concomitant quantitative analysis of the two toxins has been developed based on conversion of penicillic acid and ochratoxin A to fluorescent derivatives by treatment with ammonia fumes.

Genetic relationships among Brazilian strains of Aspergillus ochraceus based on RAPD and ITS sequences

2004 ◽  
Vol 50 (11) ◽  
pp. 985-988 ◽  
Author(s):  
Maria Helena Pelegrinelli Fungaro ◽  
Marciane Magnani ◽  
Laurival Antônio Vilas-Boas ◽  
Patrícia Cristina Vissotto ◽  
Márcia Cristina Furlaneto ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Sequence Data ◽  
Genetic Relationships ◽  
Its Region ◽  
Aspergillus Ochraceus ◽  
Coffee Bean ◽  
Coffee Beans ◽  
Major Species ◽  
Group A ◽  
Group B

Ochratoxin A (OA) is a mycotoxin that has been found in coffee beans and coffee beverages. Its toxicological profile includes carcinogenicity, nephrotoxicity, and immunotoxicity. Aspergillus ochraceus is the major species responsible for OA production in Brazilian coffee beans. The genetic relationships among 25 A. ochraceus strains collected from Brazilian coffee-bean samples were determined based on RAPD and internal transcribed spacer (ITS) sequence data. The isolates were resolved into 2 distinct groups, one with 4 strains (group A) and the other with 21 strains (group B). Specific nucleotide variations characterizing group A and B were found for both ITS1 and ITS2 regions. Group B is a new group proposed here to accommodate the majority of the Brazilian isolates. Each group was found to contain both toxigenic and nontoxigenic strains, indicating that there is no association between molecular genotypes and the ability to produce OA.Key words: Aspergillus ochraceus, ochratoxin A, ITS region (ITS1–5.8S–ITS2), RAPD.

scholarly journals Production of Ochratoxin A by Aspergillus ochraceus Isolated in Japan from Moldy Rice

1970 ◽  
Vol 20 (3) ◽  
pp. 452-454 ◽  
Author(s):  
Mikio Yamazaki ◽  
Yukio Maebayashi ◽  
Komei Miyaki
Keyword(s):  
Ochratoxin A ◽  
Aspergillus Ochraceus

scholarly journals DETERMINATION OF OPTIMUM CULTURE CONDITIONS FOR MYCELIAL GROWTH OF Macrolepiota procera MUSHROOM

2020 ◽  
Vol 19 (1) ◽  
pp. 11-20
Author(s):  
Aysun Pekşen ◽  
Beyhan Kibar
Keyword(s):  
Yeast Extract ◽  
Mycelial Growth ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
Malt Extract ◽  
The Public ◽  
Carbon And Nitrogen ◽  
Ph Values ◽  
Incubation Temperatures ◽  
Macrolepiota Procera

Macrolepiota procera, commonly called the Parasol Mushroom, is a delicious mushroom collected from the nature and commonly consumed by the public in many regions of Turkey. This study was conducted to determine the optimum culture conditions (pH, temperature, carbon and nitrogen sources) for mycelial growth of M. procera. Three pH values (pH 5.0, 5.5 and 6.0), four incubation temperatures (15, 20, 25 and 30°C), seven carbon (C) sources (dextrose, glucose, lactose, maltose, mannitol, sucrose and xylose) and six nitrogen (N) sources ((NH4)2HPO4, NH4NO3 and Ca(NO3)2, malt extract, peptone and yeast extract) were investigated. In the second step of the study, the effect of seven pH values (4.0, 4.5, 5.0, 5.5, 6.0, 6.5 and 7.0) on the mycelial colony diameter was examined at 20 and 25°C since these temperatures gave the best mycelial growth in the previously conducted temperature experiment. The best mycelial growth was determined at pH 6.0. The optimum temperature for mycelial growth of M. procera was found as 25°C. The use of glucose as carbon source and yeast extract and peptone as nitrogen source in the culture medium gave the best results for mycelial growth. Determining of optimum culture conditions for mycelial growth of M. procera will provide important contributions to the fortcoming studies on it’s commercially cultivation in Turkey.

Agrobacterium-mediated insertional mutagenesis of the ochratoxigenic fungus Aspergillus westerdijkiae

2007 ◽  
Vol 53 (1) ◽  
pp. 148-151 ◽  
Author(s):  
Marcia M Mata ◽  
Marta H Taniwaki ◽  
Beatriz T Iamanaka ◽  
Daniele Sartori ◽  
André L.M Oliveira ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Insertional Mutagenesis ◽  
Aspergillus Ochraceus ◽  
Agrobacterium Mediated Transformation ◽  
Morphological Variations ◽  
Carcinogenic Potential ◽  
Coffee Beans ◽  
Aspergillus Westerdijkiae ◽  
Polymerase Chain ◽  
First Time

Aspergillus westerdijkiae is a potent ochratoxin A (OTA) producer that has been found in coffee beans. OTA is known to have nephrotoxic effects and carcinogenic potential in animal species. Here we report for the first time the Agrobacterium-mediated transformation for Aspergillus westerdijkiae and the generation of ochratoxin-defective mutants. Conidia were transformed to hygromycin B resistance using strain AGL-1 of Agrobacterium tumefaciens. The obtained transformation frequency was up to 47 transformants per 106 target conidia. Among 600 transformants, approximately 5% showed morphological variations. Eight transformants with consistently reduced OTA production were obtained. Two of these transformants did not produce OTA (detection limit: 0.1 µg/kg); the other six mutants produced lower amounts of OTA (1%–32%) compared with the wild-type strain. By using thermal asymmetric interlaced polymerase chain reaction, we successfully identified a putative flavin adenine dinucleotide monooxygenase gene.Key words: Aspergillus ochraceus, Aspergillus westerdijkiae, Agrobacterium-mediated transformation, Agrobacterium-mediated insertional mutagenesis, ochratoxin A.

Resistance of Spirulina platensis to Ammonia at High pH Values

1991 ◽  
Vol 32 (7) ◽  
pp. 953-958 ◽  
Author(s):  
Shimshon Belkin ◽  
Sammy Boussiba
Keyword(s):  
Spirulina Platensis ◽  
High Ph ◽  
Ph Values
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