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Sample records for flavus aspergillus niger

  1. Antibiotic Extraction as a Recent Biocontrol Method for Aspergillus Niger andAspergillus Flavus Fungi in Ancient Egyptian mural paintings

    NASA Astrophysics Data System (ADS)

    Hemdan, R.; et al.

    Biodeterioration of mural paintings by Aspergillus niger and Aspergillus flavus Fungi has been proved in different mural paintings in Egypt nowadays. Several researches have studied the effect of fungi on mural paintings, the mechanism of interaction and methods of control. But none of these researches gives us the solution without causing a side effect. In this paper, for the first time, a recent treatment by antibiotic "6 penthyl α pyrone phenol" was applied as a successful technique for elimination of Aspergillus niger and Aspergillus flavus. On the other hand, it is favorable for cleaning Surfaces of Murals executed by tembera technique from the fungi metabolism which caused a black pigments on surfaces.

  2. [Effect of alcoholic extracts of wild plants on the inhibition of growth of Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium moniliforme and Fusarium poae moulds].

    PubMed

    Tequida-Meneses, Martín; Cortez-Rocha, Mario; Rosas-Burgos, Ema Carina; López-Sandoval, Susana; Corrales-Maldonado, Consuelo

    2002-06-01

    Fungicidal activity of wild plants Larrea tridentata, Karwinskia humboldtiana, Ricinus communis, Eucalyptus globulus, Ambrosia ambrosioides, Nicotiana glauca, Ambrosia confertiflora, Datura discolor, Baccharis glutinosa, Proboscidea parviflora, Solanum rostratum, Jatropha cinerea, Salpianthus macrodonthus y Sarcostemma cynanchoides was evaluated against the moulds species Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium poae y Fusarium moniliforme moulds species. Alcoholic extracts 6% (w/v) were prepared using six grams of dried plant powders (leaves and stems) and alcohol (70% ethanol or 70% methanol). A spore suspension (1x10(6); ufc/ml) of each mould was prepared by adding saline solution (0.85%) and 0.1% tween 80. The extracts were mixed with Czapeck yeast agar (CYA) at 45-50 degrees C in 1:10 relation on Petri dishes. Triplicate Petri dishes of each treatment and for each mould were centrally inoculated and three Petri dishes were used without treatment as controls. The inoculated dishes and controls were incubated at 25 +/- 2 degrees C for eight days. The incubated dishes were examined each 48 h and after the colony diameter (radial growth) was measured. Two mould species were controlled by L. tridentata, B. glutinosa and P. parviflora. Extracts of L. tridentata in methanol or ethanol at 41.5-100% inhibited all six species of moulds. PMID:12828509

  3. Hybridization between Aspergillus flavus and Aspergillus parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To date the sexual stages or teleomorphs have been described for three aflatoxigenic species in Aspergillus section Flavi: Petromyces flavus, P. parasiticus and P. nomius. In this study we examined the possibility of interspecific matings between A. flavus and A. parasiticus. These species can b...

  4. 76 FR 16297 - Aspergillus flavus

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of the microbial pesticide, Aspergillus flavus AF36, in or on corn food and feed commodities, when applied/used as an antifungal agent. The Arizona Cotton Research and Protection Council submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an amendment to the......

  5. Sexual reproduction in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is the major producer of carcinogenic aflatoxins in crops worldwide and is also an important opportunistic human pathogen in aspergillosis. The sexual state of this heterothallic fungus is described from crosses between strains of the opposite mating type. Sexual reproduction oc...

  6. Cryptic Sexuality in Aspergillus parasiticus and A. flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascomycetous fungi of the genus Aspergillus comprise a wide variety of species of biotechnological importance (e.g. A. sojae, A. oryzae, A. niger) as well as pathogens and toxin producers (e.g. A. flavus, A. parasiticus, A. fumigatus, A. nidulans). With the exception of A. nidulans, which is a homot...

  7. NITRIFICATION BY ASPERGILLUS FLAVUS1

    PubMed Central

    Marshall, K. C.; Alexander, M.

    1962-01-01

    Marshall, K. C. (Cornell University, Ithaca, N. Y.) and M. Alexander. Nitrification by Aspergillus flavus. J. Bacteriol. 83:572–578. 1962.—Aspergillus flavus has been shown to produce bound hydroxylamine, nitrite, and nitrate when grown in peptone, amino acid, or buffered ammonium media. Free hydroxylamine was not detected in these cultures, but it was found in an unbuffered ammonium medium in which neither nitrite nor nitrate was formed. Evidence was obtained for the presence of β-nitropropionic acid in the filtrate of an actively nitrifying culture. Alumina treatment of an ammonium medium prevented the formation by growing cultures of nitrite and nitrate but not bound hydroxylamine. The effect of alumina treatment was reversed by the addition of 10−3m CeCl3 to the medium. Extracts of the fungus contained peroxidase and an enzyme capable of catalyzing the production of nitrite from β-nitropropionic acid. The nitrite-forming enzyme is apparently specific for β-nitropropionate; no activity was found with nitromethane, nitroethane, and nitropropane as substrates. Nitrate was not reduced to nitrite nor was nitrite oxidized to nitrate by the hyphal extracts. The significance of these observations in nitrification by A. flavus is discussed. PMID:14470254

  8. Genomics of Aspergillus flavus mycotoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aspergilli show immense ecological and metabolic diversity. To date, the sequences of fifteen different Aspergillus genomes have been determined providing scientists with an exciting resource to improve the understanding of Aspergillus molecular genomics. Aspergillus flavus, one of the most wide...

  9. Aspergillus flavus Genomics for Controlling Aflatoxin Contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main objectives of the Aspergillus flavus genomics program are to identify genes and regulatory components involved in aflatoxin biosynthesis for solving aflatoxin contamination in agricultural crops. A. flavus Expressed Sequence Tags (EST), microarray and whole genome sequencing have been achi...

  10. Recombination and cryptic heterokaryosis in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a pathogen of many agronomically important crops worldwide and can also cause human and animal diseases. A. flavus is the major producer of aflatoxins (AFs), which are carcinogenic secondary metabolites. In the United States, mycotoxins have been estimated to cause agricultur...

  11. Interaction between maize seed and Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is an opportunistic fungal pathogen that colonizes maize seeds and contaminates them with aflatoxin. The fungus is localized in the endosperm and aleurone. To investigate the plant microbe interaction, we conducted histological and molecular studies to characterize the internal co...

  12. Evaluation of aflatoxin degradation by Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are highly toxic and hepatocarcinogenic compounds produced by Aspergillus flavus and A. parasiticus during infection of corn (maize), peanuts, cotton seed, and tree nuts (Figure 1). To minimize exposure to aflatoxins the U.S. Food and Drug Administration enforces a 20 ppb limit of aflatox...

  13. Genomic analysis of aspergillus flavus pathogenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and Fusarium verticillioides colonize developing maize seeds and contaminate them with mycotoxins. Maize genotypes differ in resistance to these fungi, but incorporation of adequate resistance into desirable hybrids has been challenging.Little is known about pathogenesis of seeds...

  14. Cyclopiazonic acid biosynthesis by Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclopiazonic acid (CPA) is an indole-tetramic acid mycotoxin produced by some strains of Aspergillus flavus. Characterization of the CPA biosynthesis gene cluster confirmed that formation of CPA is via a three-enzyme pathway. This review examines the structure and organization of the CPA genes, elu...

  15. Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines w...

  16. Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

    PubMed Central

    Chang, Perng-Kuang; Ehrlich, Kenneth C.; Fujii, Isao

    2009-01-01

    Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations. PMID:22069533

  17. Nuclear heterogeneity in conidial populations of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a major producer of aflatoxin and an opportunistic pathogen for a wide range of hosts. Understanding genotypic and phenotypic variations within strains of A. flavus is important for controlling disease and reducing aflatoxin contamination. A. flavus is multinucleate and predomi...

  18. Ecology, development and gene regulation in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is one of the most widely known species of Aspergillus. It was described as a species in 1809 and first reported as a plant pathogen in 1920. More recently, A. flavus has emerged as an important opportunistic pathogen and is now rec¬ognized as the second leading cause of aspergill...

  19. A first glance into the genome sequence of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins, produced by Aspergillus flavus and A. parasiticus, are toxic and carcinogenic metabolites. They contaminate agricultural crops before harvest and post harvest grains during storage. In order to reduce and eliminate aflatoxin contamination of food and feed, Aspergillus flavus genomics p...

  20. Scleral Buckle Infection with Aspergillus Flavus

    PubMed Central

    Bouhaimed, Manal; Al-Dhibi, Hassan; Al-Assiri, Abdullah

    2008-01-01

    Purpose: To present a case of scleral buckle infection with Aspergillus flavus in a tertiary eye center in Saudi Arabia. Methods: A retrospective case report of a 28-year-old Saudi male who presented with a six-month history of conjunctival injection and discharge from the left eye which had undergone uncomplicated conventional retinal detachment surgery, at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia, in the form of cryopexy, subretinal fluid drainage and scleral buckle (grooved segmental sponge and circumferential band with sleeve) for a macula on retinal detachment four years earlier. A diagnosis of infected extruded scleral buckle was made and the buckle was removed. Results: The infected scleral buckle was removed under local anesthesia with administration of sub-conjunctival irrigation of 50 mg solution of Vancomycin, and sub-conjunctival injection of 25mg of Vancomycin. Post operative microbiological studies revealed infection with silver staining of moderate Aspergillus flavus hyphae. Visual acuity of the left eye improved from 20/200 before surgery to 20/60 in the two years follow-up visit. Conclusion: This case report indicates the importance of considering infection with multiple organisms – including fungal ones – in cases of scleral buckle infections in our population. PMID:20379425

  1. Biotransformation of Stypotriol triacetate by Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Areche, Carlos; Vaca, Inmaculada; Labbe, Pamela; Soto-Delgado, Jorge; Astudillo, Luis; Silva, Mario; Rovirosa, Juana; San-Martin, Aurelio

    2011-07-01

    Biological transformation of the meroditerpenoid, stypotriol triacetate ( 1) by the fungi Aspergillus niger, Cunninghamella elegans, Gibberella fujikuroi and Mucor plumbeus was studied. The incubation of 1 with A. niger yielded the new compound 6',14-diacetoxy-stypol-4,5-dione ( 2) whose structure was established by 1H, 13C and 2D NMR and supported by DFT/GIAO.

  2. Nutrient environment influences competition among Aspergillus flavus genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Structures of Aspergillus flavus populations, shaped by intraspecific competition, influence the incidences and severities of crop aflatoxin contamination. Competition for nutrients may be one factor modulating intraspecific interactions, but influences of specific types and concentrations of nutrie...

  3. Population shifts and mating-type heterokaryosis in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a fungal pathogen of many agronomically important crops worldwide. We sampled A. flavus strains from a cornfield in Rocky Mount, NC. This field was planted in 2010 and plots were inoculated at tasselling with either AF36 or NRRL 21882 (=Afla-Guard) biocontrol strains, both of...

  4. Mating-type heterokaryosis and population shifts in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a fungal pathogen of many agronomically important crops worldwide. We sampled A. flavus strains from a cornfield in Rocky Mount, NC. This field was planted in 2010 and plots were inoculated at tasselling with either AF36 or NRRL 21882 (=Afla-Guard) biocontrol strains, both of...

  5. The maize rachis affects Aspergillus flavus movement during ear development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus expressing green fluorescent protein (GFP) was used to follow infection in ears of maize hybrids resistant and susceptible to the fungus. Developing ears were needle-inoculated with GFP-transformed A. flavus 20 days after silk emergence, and GFP fluorescence in the pith was evalu...

  6. Potential of Aspergillus flavus Genomics for Applications in Biotechnology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a common saprophyte and opportunistic pathogen that survives in the natural environment by extracting nutrition from plant debris, insect carcasses and a variety of other carbon sources. A. flavus produces numerous secondary metabolites and hydrolytic enzymes. The primary obj...

  7. Population structure of Aspergillus flavus before and after biocontrol treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a fungal pathogen of many important crops worldwide. We sampled A. flavus strains from a cornfield in Rocky Mount, North Carolina, over a period of two years. Plots were inoculated at tasselling with either AF36 or NRRL 21882 (=Afla-Guard) biocontrol strains, both of which are ...

  8. Population dynamics of Aspergillus flavus following biocontrol treatment of corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a fungal pathogen of many agronomically important crops worldwide. We sampled A. flavus strains from a cornfield in Rocky Mount, North Carolina, over a period of two years. The field was planted in 2010 and plots were inoculated at tasselling with either AF36 or NRRL 21882 (=Af...

  9. Sexual reproduction in Aspergillus flavus sclerotia naturally produced in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is the major producer of carcinogenic aflatoxins worldwide in crops. Populations of A. flavus are characterized by high genetic variation and the source of this variation is likely sexual reproduction. The fungus is heterothallic and laboratory crosses produce ascospore-bearing ...

  10. Population ecology of Aspergillus flavus associated with Mississippi Delta Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the source of Aspergillus flavus is required to effectively manage within-field aflatoxin contamination of maize (Zea mays L.). Studies assessed the density of A. flavus propagules and other soil microflora (Fusarium spp., total fungi) associated with Mississippi Delta soils, and corr...

  11. What can Aspergillus flavus genome offer for mycotoxin research?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genomic study of filamentous fungi has made significant advances in recent years, and the genomes of several species in the genus Aspergillus have been sequenced, including Aspergillus flavus. This ubiquitous mold is present as a saprobe in a wide range of agricultural and natural habits, and c...

  12. WHOLE GENOME COMPARISON OF ASPERGILLUS FLAVUS AND A. ORYZAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a plant and animal pathogen that also produces the potent carcinogen aflatoxin. Aspergillus oryzae is a closely related species that has been used for centuries in the food fermentation industry and is generally regarded as safe (GRAS). Whole genome sequences for these two fu...

  13. Characterization of aflatoxigenic Aspergillus flavus and A. parasiticus strain isolates from animal feedstuffs in northeastern Iran

    PubMed Central

    Davari, E; Mohsenzadeh, M; Mohammadi, Gh; Rezaeian-Doloei, R

    2015-01-01

    Aflatoxins are secondary toxic metabolites produced by some Aspergillus spp. particularly, Aspergillus flavus and A. parasiticus that contaminate food and feed. The objective of this study was to evaluate the contamination of feedstuffs with Aspergillus spp. and detect genes involved in the aflatoxin biosynthesis pathway of A. flavus and A. parasiticus isolates. A total of 110 cow feed samples (comprised of silage, concentrate, hay and total mixed ration) from 30 industrial and semi-industrial dairy farms of Khorasan Razavi province, northeastern Iran, were examined using cultural and PCR methods. 68 (61.82%) Aspergillus spp. were isolated from 110 samples of feedstuff. The predominant Aspergillus isolates were A. fumigates (21.81%), followed by A. flavus (17.27%), A. niger (10%), A. parasiticus (8.18%), and A. oryzae (4.54%). Fungal contamination levels of industrial and semi-industrial dairy farm samples were not significantly different (P>0.05). Using four sets of primers, a quadruplex PCR was developed to detect genes (nor1, ver1, omtA and aflR) at different loci coding enzymes in the aflatoxin biosynthesis pathway of A. flavus and A. parasiticus strains. Out of 28 strains of A. flavus and A. parasiticus, 10 isolates (35.71%) showed a quadruplet pattern indicating the important genes involved in the aflatoxin biosynthesis pathway, encoded for functional products. These isolates were confirmed to be aflatoxigenic by Thin Layer Chromatography. 18 isolates (64.29%) had three, two and single molecular patterns. The results obtained by this study show that rapid and specific detection of aflatoxigenic molds is important to ensure the microbiological safety of feedstuffs. PMID:27175167

  14. Nitrification of Aspartate by Aspergillus flavus

    PubMed Central

    Hatcher, H. J.; Schmidt, E. L.

    1971-01-01

    Heterotrophic conversion of l-aspartic acid to nitrification products by Aspergillus flavus was studied in a replacement incubation system. Numerous amino acids supported nitrification; aspartate and glutamate were about equivalent as the best sources of nitrate. Addition of sodium bicarbonate to the incubation system substantially enhanced nitrate formation for all nitrifiable amino acids except aspartic acid, but the basis for the bicarbonate effect is obscure. The yield of nitrate from l-aspartate was not approached by forms of aspartic acid resulting from substitution on the beta carbon, the amino nitrogen, or the gamma carboxyl group or by aspartate presented as the d-configuration. There was no relationship between nitrate formation and the occurrence of such possible intermediates as nitrite, bound hydroxylamine, ammonia, aspergillic acid, and beta-nitropropionic acid. Uniformly labeled 14C-l-aspartate that was nitrified in replacement incubation led to no accumulation of label in possible nitrification products in the culture filtrate. Label was found in components of the mycelium after acid hydrolysis, with heaviest accumulation in what appeared to be glucosamine and an unidentified compound, possibly acetylglucosamine. Detectable label was redistributed into serine, glycine, and threonine. Images PMID:5549699

  15. Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B₁.

    PubMed

    Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan

    2014-11-01

    Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment. PMID:25401962

  16. Comparison of different inoculating methods to evaluate the pathogenicity and virulence of Aspergillus niger on two maize hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year field study was conducted to determine the effects of inoculation techniques on the aggressiveness of Aspergillus niger kernel infection in A. flavus resistant and susceptible maize hybrids. Ears were inoculated with the silk-channel, side-needle, and spray techniques 7 days after midsilk...

  17. Enhanced diversity and aflatoxigenicity in interspecific hybrids of Aspergillus flavus and Aspergillus parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and A. parasiticus are two of the most important aflatoxin-producing species that contaminate agricultural commodities worldwide. Both species are heterothallic and undergo sexual reproduction in laboratory crosses. Here, we examine the possibility of interspecific matings betwe...

  18. Population ecology of Aspergillus flavus associated with Mississippi Delta soils.

    PubMed

    Zablotowicz, R M; Abbas, H K; Locke, M A

    2007-10-01

    Understanding the source of Aspergillus flavus is required to manage aflatoxin contamination of maize (Zea mays L.). Studies assessed A. flavus propagules, Fusarium spp., and total fungi associated with Mississippi Delta soils. Soils from 12 and 15 sites were collected in 2000 and 2001, respectively. The propagule density of A. flavus ranged from log(10) 2.0 to 4.3 colony-forming units (cfu) g(-1) soil, while total fusaria ranged from log(10) 3.0 to 5.4 cfu g(-1) soil. The highest populations of A. flavus were associated with soils containing higher organic matter, especially in sites under a no-tillage management. The frequency of aflatoxin production in isolates ranged from 13 to 81% depending on soil. In 2001, there was a highly significant correlation between A. flavus and the history of maize cultivation. Soil fertility factors such as organic matter content, nitrate and extractable phosphorus correlated with the density of Aspergillus, Fusarium spp., and total fungi. The relationship between soil parameters and Aspergillus populations may be useful in predicting the contribution of soil microflora to aflatoxin contamination. PMID:17886181

  19. Nonaflatoxigenic Aspergillus flavus TX9-8 Competitively Prevents Aflatoxin Production by A. flavus Isolates of Large and Small Sclerotial Morphotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxigenic Aspergillus flavus is the main etiological agent for aflatoxin contamination of crops. Using nonaflatoxigenic A. flavus isolates to competitively exclude toxigenic A. flavus isolates in agricultural fields has become an adopted approach to reduce aflatoxin contamination. We determined th...

  20. Evidence of aneuploidy modulating aflatoxigenicity in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a well-known pathogen of many important agricultural commodities and is a major producer of aflatoxins, which are carcinogenic polyketides that pose a serious health risk to humans and animals. Aflatoxin contamination in peanut exports worldwide accounts for as much as $450 mi...

  1. Mating-type heterokaryosis in Aspergillus flavus in North Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a well-known pathogen of many important agricultural commodities and is a major producer of aflatoxins (AFs), which are carcinogenic polyketides that pose a serious health risk to humans and animals. Recently, heterokaryosis and the presence of cryptic alleles were shown to ex...

  2. Genetic Response to Seed Colonizatin by Aspergillus flavus in Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies to evaluate peanut genotypes for in vitro resistance to seed colonization by Aspergillus flavus have not resulted in the development of cultivars with resistance to aflatoxin contamination in the field. New breeding lines showing pre-harvest field resistance to aflatoxin contaminat...

  3. Regulation of Aspergillus flavus Aflatoxin Biosynthesis and Development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The filamentous fungus Aspergillus flavus produces a family of potent mutagenic and carcinogenic compounds collectively known as aflatoxins (AF). These secondary metabolites contaminate a number of oilseed crops during growth of the fungus and this can result in severe negative economic and health i...

  4. Characterization of toxigenic and atoxigenic Aspergillus flavus isolates from pistachio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty eight Aspergillus flavus isolates collected from a pistachio orchard in California were analyzed for production of aflatoxin (AF), cyclopiazonic acid (CPA), vegetative compatibility groups (VCGs) and mating types. All toxigenic isolates produced both AFB1 and CPA. Twenty-one percent of the i...

  5. METHODS TO SAMPLE AIR BORNE PROPAGULES OF ASPERGILLUS FLAVUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several techniques (cyclone samplers, filter samplers and rotorods) were evaluated for detection of airborne Aspergillus flavus Link propagules in a cultivated region of southwest Arizona. Cyclone samplers operated continuously for 168 h (7 d) collected a dry sample that was ideal for quantificatio...

  6. Sexual reproduction in Aspergillus flavus and A. parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and A. parasiticus are potent producers of carcinogenic and hepatotoxic aflatoxins, polyketide-derived secondary metabolites that contaminate a wide variety of agricultural crops. Strains with opposite mating-type genes MAT1-1 and MAT1-2 within each species were crossed in an att...

  7. Recombination and cryptic heterokaryosis in experimental populations of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus infects both plants and animals, and is of toxicological importance due to its production of aflatoxins (AFs) and other mycotoxins. Mycotoxins can cause agricultural losses totaling upwards of $1.4 billion annually. Recent efforts to reduce AF concentrations have focused on the us...

  8. Molecular characterization of atoxigenic Aspergillus flavus isolates collected in China.

    PubMed

    Wei, Dandan; Zhou, Lu; Selvaraj, Jonathan Nimal; Zhang, Chushu; Xing, Fuguo; Zhao, Yueju; Wang, Yan; Liu, Yang

    2014-07-01

    Aspergillus flavus strains were isolated from peanut fields of Liaoning, Shandong, Hubei and Guangdong Provinces in China, and identified through phenotypic and molecular approaches. Of the 323 A. flavus strains isolated, 76 strains did not produce aflatoxins detectable by UPLC. The incidence of atoxigenic A. flavus strains decreased with increase in temperature and increased with increase in latitude in different geographical locations. Amplification of all the aflatoxin genes in the aflatoxin gene cluster in the atoxigenic isolates showed that there were 25 deletion patterns (A-Y), with 22 deletion patterns identified for the first time. Most of the atoxigenic A. flavus isolates with gene deletions (97%) had deletions in at least one of the four genes (aflT, nor-1, aflR, and hypB), indicating that these four genes could be targeted for rapid identification of atoxigenic strains. The atoxigenic isolates with gene deletions, especially the isolates with large deletions, are potential candidates for aflatoxin control. PMID:24879349

  9. Aspergillus flavus SUMO Contributes to Fungal Virulence and Toxin Attributes.

    PubMed

    Nie, Xinyi; Yu, Song; Qiu, Mengguang; Wang, Xiuna; Wang, Yu; Bai, Youhuang; Zhang, Feng; Wang, Shihua

    2016-09-01

    Small ubiquitin-like modifiers (SUMOs) can be reversibly attached to target proteins in a process known as SUMOylation, and this process influences several important eukaryotic cell events. However, little is known regarding SUMO or SUMOylation in Aspergillus flavus. Here, we identified a novel member of the SUMO family in A. flavus, AfSumO, and validated the existence of SUMOylation in this pathogenic filamentous fungus. We investigated the roles of AfsumO in A. flavus by determining the effects of AfsumO mutations on the growth phenotype, stress response, conidia and sclerotia production, aflatoxin biosynthesis, and pathogenicity to seeds, and we found that SUMOylation plays a role in fungal virulence and toxin attributes. Taken together, these results not only reveal potential mechanisms of fungal virulence and toxin attributes in A. flavus but also provide a novel approach for promising new control strategies of this fungal pathogen. PMID:27532332

  10. Environmental and Developmental Factors Influencing Aflatoxin Production by Aspergillus flavus and Aspergillus parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic mycotoxins formed by a number of fungi in the genus Aspergillus. The major fungi responsible for aflatoxin formation in crop seeds in the field and in storage are Aspergillus flavus and A. parasiticus. This review emphasizes developmental, environmental, biological and ...

  11. Shedding light on Aspergillus niger volatile exometabolome

    PubMed Central

    Costa, Carina Pedrosa; Gonçalves Silva, Diogo; Rudnitskaya, Alisa; Almeida, Adelaide; Rocha, Sílvia M.

    2016-01-01

    An in-depth exploration of the headspace content of Aspergillus niger cultures was performed upon different growth conditions, using a methodology based on advanced multidimensional gas chromatography. This volatile fraction comprises 428 putatively identified compounds distributed over several chemical families, being the major ones hydrocarbons, alcohols, esters, ketones and aldehydes. These metabolites may be related with different metabolic pathways, such as amino acid metabolism, biosynthesis and metabolism of fatty acids, degradation of aromatic compounds, mono and sesquiterpenoid synthesis and carotenoid cleavage. The A. niger molecular biomarkers pattern was established, comprising the 44 metabolites present in all studied conditions. This pattern was successfully used to distinguish A. niger from other fungi (Candida albicans and Penicillium chrysogenum) with 3 days of growth by using Partial Least Squares-Discriminant Analysis (PLS-DA). In addition, PLS-DA-Variable Importance in Projection was applied to highlight the metabolites playing major roles in fungi distinction; decreasing the initial dataset to only 16 metabolites. The data pre-processing time was substantially reduced, and an improvement of quality-of-fit value was achieved. This study goes a step further on A. niger metabolome construction and A. niger future detection may be proposed based on this molecular biomarkers pattern. PMID:27264696

  12. Shedding light on Aspergillus niger volatile exometabolome.

    PubMed

    Costa, Carina Pedrosa; Gonçalves Silva, Diogo; Rudnitskaya, Alisa; Almeida, Adelaide; Rocha, Sílvia M

    2016-01-01

    An in-depth exploration of the headspace content of Aspergillus niger cultures was performed upon different growth conditions, using a methodology based on advanced multidimensional gas chromatography. This volatile fraction comprises 428 putatively identified compounds distributed over several chemical families, being the major ones hydrocarbons, alcohols, esters, ketones and aldehydes. These metabolites may be related with different metabolic pathways, such as amino acid metabolism, biosynthesis and metabolism of fatty acids, degradation of aromatic compounds, mono and sesquiterpenoid synthesis and carotenoid cleavage. The A. niger molecular biomarkers pattern was established, comprising the 44 metabolites present in all studied conditions. This pattern was successfully used to distinguish A. niger from other fungi (Candida albicans and Penicillium chrysogenum) with 3 days of growth by using Partial Least Squares-Discriminant Analysis (PLS-DA). In addition, PLS-DA-Variable Importance in Projection was applied to highlight the metabolites playing major roles in fungi distinction; decreasing the initial dataset to only 16 metabolites. The data pre-processing time was substantially reduced, and an improvement of quality-of-fit value was achieved. This study goes a step further on A. niger metabolome construction and A. niger future detection may be proposed based on this molecular biomarkers pattern. PMID:27264696

  13. Potential involvement of Aspergillus flavus laccases in peanut invasion at low water potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus (Link) accumulates aflatoxins in peanuts, mainly affecting immature kernels during drought. Peanut invasion by A. flavus induces synthesis of phytoalexins, mostly stilbenoids, as a plant defense mechanism. Fungal laccases are often related to pathogenicity, and among other subst...

  14. Genes Differentially Expressed by Aspergillus flavus Strains After Loss of Aflatoxin Production by Serial Transfers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic fungal secondary metabolites produced by Aspergillus flavus and other closely related species. To better understand the molecular events that are associated with aflatoxin production, three separate nonaflatoxigenic A. flavus strains were produced through serial transfer...

  15. Comparative Genomics of Aspergillus flavus and A. oryzae: An Early View

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus produces aflatoxins and is the second leading cause of aspergillosis in immunocompromised individuals. Aspergillus oryzae, on the other hand, has been used for centuries in Japan for the fermentation of food. The recently available whole genome sequences of Aspergillus flavus an...

  16. Lipids in Aspergillus flavus-maize interaction

    PubMed Central

    Scarpari, Marzia; Punelli, Marta; Scala, Valeria; Zaccaria, Marco; Nobili, Chiara; Ludovici, Matteo; Camera, Emanuela; Fabbri, Anna A.; Reverberi, Massimo; Fanelli, Corrado

    2014-01-01

    In some filamentous fungi, the pathways related to the oxidative stress and oxylipins production are involved both in the process of host-recognition and in the pathogenic phase. In fact, recent studies have shown that the production of oxylipins in filamentous fungi, yeasts and chromists is also related to the development of the organism itself and to mechanisms of communication with the host at the cellular level. The oxylipins, also produced by the host during defense reactions, are able to induce sporulation and to regulate the biosynthesis of mycotoxins in several pathogenic fungi. In A. flavus, the oxylipins play a crucial role as signals for regulating the biosynthesis of aflatoxins, the conidiogenesis and the formation of sclerotia. To investigate the involvement of an oxylipins based cross-talk into Z. mays and A. flavus interaction, we analyzed the oxylipins profile of the wild type strain and of three mutants of A. flavus that are deleted at the Aflox1 gene level also during maize kernel invasion. A lipidomic approach has been addressed through the use of LC-ToF-MS, followed by a statistical analysis of the principal components (PCA). The results showed the existence of a difference between the oxylipins profile generated by the WT and the mutants onto challenged maize. In relation to this, aflatoxin synthesis which is largely hampered in vitro, is intriguingly restored. These results highlight the important role of maize oxylipin in driving secondary metabolism in A. flavus. PMID:24578700

  17. Fingernail Onychomycosis Due to Aspergillus niger.

    PubMed

    Kim, Dong Min; Suh, Moo Kyu; Ha, Gyoung Yim; Sohng, Seung Hyun

    2012-11-01

    Onychomycosis is usually caused by dermatophytes, but some species of nondermatophytic molds and yeasts are also associated with nail invasion. Aspergillus niger is a nondermatophytic mold which exists as an opportunistic filamentous fungus in all environments. Here, we report a case of onychomycosis caused by A. niger in a 66-year-old female. The patient presented with a black discoloration and a milky white base and onycholysis on the proximal portion of the right thumb nail. Direct microscopic examination of scrapings after potassium hydroxide (KOH) preparation revealed dichotomous septate hyphae. Repeated cultures on Sabouraud's dextrose agar (SDA) without cycloheximide produced the same black velvety colonies. No colony growth occurred on SDA with cycloheximide slants. Biseriate phialides covering the entire vesicle with radiate conidial heads were observed on the slide culture. The DNA sequence of the internal transcribed spacer region of the clinical sample was a 100% match to that of A. niger strain ATCC 16888 (GenBank accession number AY373852). A. niger was confirmed by KOH mount, colony identification, light microscopic morphology, and DNA sequence analysis. The patient was treated orally with 250 mg terbinafine daily and topical amorolfine 5% nail lacquer for 3 months. As a result, the patient was completely cured clinically and mycologically. PMID:23197914

  18. The complete mitochondrial genome sequence of Aspergillus flavus.

    PubMed

    Yan, Zhengsong; Chen, Dan; Shen, Yiping; Ye, Baodong

    2016-07-01

    Aspergillus flavus is a haploid filamentous fungus that is common in the environment and has been implicated in human infections. The complete mitochondrial genome of A. flavus has been determined by high-throughput sequencing technology in this work. Our study revealed that the mitochondrial genome of A. flavus is 31,602 bp long, with an A + T content of 74.83%, which consists of a usual set of mitochondrial proteins and RNA genes, including large and small ribosomal RNAs, 15 proteins, and 20 tRNA genes and contains two introns. Notably, it also contains two hypothetical proteins without obvious homology to any known proteins. All structural genes are located on one strand and are apparently transcribed in one direction. Codon usage analysis indicated that all protein coding genes employ the standard fungal mitochondrial start and stop codons; and the nucleotide bias toward AT was also reflected in the codon usage. The complete mitochondrial genomes of A. flavus would be useful for future investigation of the genetic, evolution, and clinical identification of Aspergillus species. PMID:25922962

  19. Genomics of peanut-Aspergillus flavus interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination caused by Aspergillus fungi is a great concern in peanut production worldwide. Pre-harvest Aspergillii infection and aflatoxin contamination are usually severe in peanuts that are grown under drought stressed conditions. Genomic research can provide new tools and resources to...

  20. Transcriptomic profiling of Aspergillus flavus in response to 5-azacytidine.

    PubMed

    Lin, Jian-Qing; Zhao, Xi-Xi; Zhi, Qing-Qing; Zhao, Ming; He, Zhu-Mei

    2013-07-01

    Aspergillus flavus is a common saprophyte and opportunistic pathogen producing aflatoxin (AF) and many other secondary metabolites. 5-Azacytidine (5-AC), a derivative of the nucleoside cytidine, is widely used for studies in epigenetics and cancer biology as an inactivator of DNA methyltransferase and is also used for studying secondary metabolism in fungi. Our previous studies showed that 5-AC affects development and inhibits AF production in A. flavus, and that A. flavus lacks DNA methylation. In this study, an RNA-Seq approach was applied to explore the mechanism of 5-AC's effect on A. flavus. We identified 240 significantly differentially expressed (Q-value<0.05) genes after 5-AC treatment, including two backbone genes respectively in secondary metabolite clusters #27 and #35. These two clusters are involved in development or survival of sclerotia. GO functional enrichment analysis showed that these significantly differentially expressed genes were mainly involved in catalytic activity and proteolytic functions. The expressed transcripts of most genes in the AF biosynthetic gene cluster in A. flavus showed no significant changes after treatment with 5-AC and were expressed at low levels, and the transcription regulator genes aflR and aflS in this cluster did not show differential expression relative to the sample without 5-AC treatment. We found that the veA gene, which encodes protein bridges VelB and LaeA, decreased profoundly the expressed transcripts, and brlA, which encodes an early regulator of development, increased its transcripts in A. flavus after 5-AC treatment. Our data support a model whereby 5-AC affects development through increasing the expression of brlA by depressing the expression of veA and AF production through suppressing veA expression and dysregulating carboxypeptidase activity, which then prevents the aflatoxisomes (vesicles) from performing their normal function in AF formation. Furthermore, the suppressed veA expression weakens or

  1. Host Genes Involved in the Interaction between Aspergillus flavus and Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination caused by Aspergillus flavus is a major concern in maize production. Understanding the complex interrelationships of genes during the A. flavus-maize interaction may be the key to developing strategies to interrupt the aflatoxin contamination process. The A. flavus Genome Seq...

  2. Genetic variability of Aspergillus flavus isolates from a Mississippi corn field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Aspergillus flavus represents a major threat to food safety and food security on a worldwide scale. Corn, peanuts, cotton, rice and edible nuts, can be colonized by A. flavus strains that produce carcinogenic aflatoxins. A biological strategy for control of toxigenic A. flavus starins inv...

  3. Atoxigenic Aspergillus flavus endemic to Italy for biocontrol of aflatoxins in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective biological control of aflatoxin­producing Aspergillus flavus with atoxigenic members of that species requires suitable A. flavus well adapted to and resident in target agroecosystems. Eighteen atoxigenic isolates of A. flavus endemic in Italy were compared for ability to reduce aflatoxin c...

  4. Selection of Aspergillus flavus isolates for biological control of aflatoxins in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Aspergillus flavus is responsible for producing carcinogenic mycotoxins, the aflatoxins, on corn (maize) and other crops. An additional harmful toxin, cyclopiazonic acid, is produced by some isolates of A. flavus. Several A. flavus strains that do not produce one or both of these mycoto...

  5. Aspergillus flavus and aflatoxin B1 in flour production.

    PubMed

    Halt, M

    1994-10-01

    This paper discusses the results of investigations of contamination with aflatoxin-producing fungi and aflatoxin B1 affecting 545 samples of wheat grains, 475 samples of intermediate products of wheat grain being milled to flour (like middlings) and 238 samples of flour. A significant contamination with moulds was detected in analyzed samples. Although Aspergillus (34.87%) and Penicillium (32.37%) dominated, other types were also present, e.g., Cladosporium, Fusarium, Mucor, Alternaria, Rhizopus, Absidia and Trichoderma (listed in order of frequency). The presence of Aspergillus flavus, the known aflatoxin producer, was detected in 9.94% of analyzed samples. Isolates of A. Flavus were capable of producing aflatoxin B1 under favourable conditions. Aflatoxin B1 was found in 76.8% of samples contaminated with A. flavus. The highest contamination with aflatoxin B1 was detected in wheat grain samples (mean value of 16.3 micrograms/kg) and in intermediate products of wheat grain being milled to flour (mean value of 11.13 micrograms/kg). Contamination was lower in flour samples (mean value of 4.13 micrograms/kg). With regard to proposed standards given by the FAO and WHO, under which the content of aflatoxin should not exceed 30 micrograms/kg in food products, only two of 96 samples did not meet these criteria. PMID:7859854

  6. Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

    NASA Astrophysics Data System (ADS)

    Ribeiro, J.; Cavaglieri, L.; Vital, H.; Cristofolini, A.; Merkis, C.; Astoreca, A.; Orlando, J.; Carú, M.; Dalcero, A.; Rosa, C. A. R.

    2011-05-01

    The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B 1 and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

  7. The population genomics of mycotoxin diversity in Aspergillus flavus and Aspergillus parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins, and especially the aflatoxins, are an enormous problem in agriculture, with aflatoxin B1 being the most carcinogenic known natural compound. The worldwide costs associated with aflatoxin monitoring and crop losses are in the hundreds of millions of dollars. Aspergillus flavus and A. par...

  8. Development and evaluation of peanut germplasm with resistance to Aspergillus flavus from core collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut (Arachis hypogaea L.), one of the main oil and cash crops in the world, is susceptible to Aspergillus flavus, resulting in loss in quality. Aspergillus flavus infection is a problem for peanut production and industry in China. Therefore, it is imperative to develop new peanut germplasm with ...

  9. Microbial transformation of curcumol by Aspergillus niger.

    PubMed

    Chen, Li-Xia; Zhang, Hui; Zhao, Qian; Yin, Shi-Yu; Zhang, Zhong; Li, Tian-Xian; Qiu, Feng

    2013-02-01

    Curcumol is a representative index component for the quality control of the essential oil of Curcuma wenyujin Y.H. Chen et C. Ling, an antivirus and anticancer drug in China. Microbial transformation of curcumol (1) by Aspergillus niger AS 3.739 yielded two products. Their structures were elucidated as 3alpha-hydroxycurcumol (2) and 3alpha-(4'-methoxy-succinyloxy)-curcumol (3) by extensive spectroscopic methods including 2D-NMR and HRESI-MS. Among them, 3 is a new compound. Esterification of the substrate with succinic acid is a novel reaction in the field of microbial transformation of natural products. Compound 2, the major transformation product of 1, was a high regio- and stereo-specific hydroxylation product and showed significant antiviral effects. PMID:23513713

  10. A tyrosinase inhibitor from Aspergillus niger.

    PubMed

    Vasantha, K Y; Murugesh, C S; Sattur, A P

    2014-10-01

    Tyrosinase, in the presence of oxygen, is the main culprit in post harvest browning of food products, resulting in the drop in its commercial value. In an effort to seek natural tyrosinase inhibitors for food applications, a screening programme was undertaken. Of the 26 fungal cultures isolated from soil samples of Agumbe forest, India, one isolate S16, identified as Aspergillus niger, gave an inhibition of 84 % against the enzyme. The inhibitor was isolated by following an enzyme inhibition assay guided purification protocol. The structure of the inhibitor was elucidated and found to be kojic acid. The IC50 of the Competitive inhibitor was found to be 8.8 μg with a Ki of 0.085 mM. PMID:25328242

  11. Structure analysis of an Aspergillus flavus kernels population in North Italy. First analysis of an Aspergillus flavus kernels population based on vegetative compatibility groups in Northern Italy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to gain insight into the causal agents of aflatoxin contamination of maize in Italy, populations of Aspergillus flavus on maize produced in the most affected area were characterized. Forty-six percent of A. flavus, isolated from maize kernels collected in 5 districts of northern Italy betwe...

  12. How Peroxisomes Affect Aflatoxin Biosynthesis in Aspergillus Flavus

    PubMed Central

    Reverberi, Massimo; Punelli, Marta; Smith, Carrie A.; Zjalic, Slaven; Scarpari, Marzia; Scala, Valeria; Cardinali, Giorgia; Aspite, Nicaela; Pinzari, Flavia; Payne, Gary A.; Fabbri, Anna A.; Fanelli, Corrado

    2012-01-01

    In filamentous fungi, peroxisomes are crucial for the primary metabolism and play a pivotal role in the formation of some secondary metabolites. Further, peroxisomes are important site for fatty acids β-oxidation, the formation of reactive oxygen species and for their scavenging through a complex of antioxidant activities. Oxidative stress is involved in different metabolic events in all organisms and it occurs during oxidative processes within the cell, including peroxisomal β-oxidation of fatty acids. In Aspergillus flavus, an unbalance towards an hyper-oxidant status into the cell is a prerequisite for the onset of aflatoxin biosynthesis. In our preliminary results, the use of bezafibrate, inducer of both peroxisomal β-oxidation and peroxisome proliferation in mammals, significantly enhanced the expression of pex11 and foxA and stimulated aflatoxin synthesis in A. flavus. This suggests the existence of a correlation among peroxisome proliferation, fatty acids β-oxidation and aflatoxin biosynthesis. To investigate this correlation, A. flavus was transformed with a vector containing P33, a gene from Cymbidium ringspot virus able to induce peroxisome proliferation, under the control of the promoter of the Cu,Zn-sod gene of A. flavus. This transcriptional control closely relates the onset of the antioxidant response to ROS increase, with the proliferation of peroxisomes in A. flavus. The AfP33 transformant strain show an up-regulation of lipid metabolism and an higher content of both intracellular ROS and some oxylipins. The combined presence of a higher amount of substrates (fatty acids-derived), an hyper-oxidant cell environment and of hormone-like signals (oxylipins) enhances the synthesis of aflatoxins in the AfP33 strain. The results obtained demonstrated a close link between peroxisome metabolism and aflatoxin synthesis. PMID:23094106

  13. Draft Genome Sequence of Aspergillus niger Strain An76

    PubMed Central

    Gong, Weili; Cheng, Zhi; Zhang, Huaiqiang; Liu, Lin; Gao, Peiji

    2016-01-01

    The filamentous fungus Aspergillus niger has become one of the most important fungi in industrial biotechnology, and it can efficiently secrete both polysaccharide-degrading enzymes and organic acids. We report here the 6,074,961,332-bp draft sequence of A. niger strain An76, and the findings provide important information related to its lignocellulose-degrading ability. PMID:26893421

  14. Effect of corn and peanut cultivation on soil populations of Aspergillus flavus and A. parasiticus in southwestern Georgia.

    PubMed Central

    Horn, B W; Greene, R L; Dorner, J W

    1995-01-01

    The effect of corn and peanut cultivation on the proportion of Aspergillus flavus to A. parasiticus in soil was examined. Soil populations were monitored in three fields during three different years in southwestern Georgia. Each field was planted in both peanuts and corn, and soil was sampled within plots for each crop. A. flavus and A. parasiticus were present in similar proportions in plots from all fields at the beginning of the growing season. A. terreus, A. niger, and A. fumigatus were the other dominant aspergilli in soil. Fields A and B did not show drought stress in peanut or corn plants, and soil populations of A. flavus and A. parasiticus remained stable during the course of the year. In field C, drought stress in corn plants with associated A. flavus infection and aflatoxin contamination greatly increased soil populations of A. flavus relative to A. parasiticus upon dispersal of corn debris to the soil surface by a combine harvester. Colonization of organic debris after it has been added to the soil may maintain soil populations of A. parasiticus despite lower crop infection. PMID:7618858

  15. Copper induction and differential expression of laccase in Aspergillus flavus.

    PubMed

    Gomaa, Ola M; Momtaz, Osama A

    2015-03-01

    Aspergillus flavus was isolated from soil and exhibited laccase activity under both constitutive and copper induced conditions. Spiking the medium with 1 mM copper sulfate resulted in an increase in the activity which reached 51.84 U/mL, a distinctive protein band was detected at 60 kDa. The extracellular enzyme was purified 81 fold using gel filtration chromatography and resulted in two different laccase fractions L1 and L2, the latter had a higher enzymatic activity which reached 79.57 U/mL and specific activity of 64.17 U/μg protein. The analysis of the spectrum of the L2 fraction showed a shoulder at 330 nm which is characteristic for T2/T3 copper centers; both copper and zinc were detected suggesting that this is an unconventional white laccase. Primers of laccase gene were designed and synthesized to recover specific gene from A. flavus . Sequence analysis indicated putative laccase (Genbank ID: JF683612) at the amino acid level suggesting a close identity to laccases from other genera containing the copper binding site. Decolorization of textile waste water under different conditions showed possible application in bioremediation within a short period of time. The effect of copper on A. flavus was concentration dependent. PMID:26221119

  16. AMINO ACID SUPPLEMENTATION REVEALS DIFFERENTIAL REGULATION OF AFLATOXIN BIOSYNTHESIS IN ASPERGILLUS FLAVUS NRRL 3357 AND ASPERGILLUS PARASITICUS SRRC 143

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic and carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and A. parasiticus. In order to better understand the molecular mechanisms that regulate aflatoxin production, the biosynthesis of the toxin in A. flavus and A. parasiticus grown in yeast extract su...

  17. Evaluation of intraspecific competition (Aspergillus flavus Link) and aflatoxin formation in suspended disc culture and preharvest maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The abilities of non-aflatoxin producing strains of Aspergillus flavus NRRL 32354; 18543; 21882; 21368 as well as domesticated koji strains Aspergillus oryzae (syn. A. flavus var. oryzae) NRRL 451; 1911; 5592; 6271; 30038 to interfere with aflatoxin formation by A. flavus NRRL 3357; 32355 were exami...

  18. Aspergillus Niger Genomics: Past, Present and into the Future

    SciTech Connect

    Baker, Scott E.

    2006-09-01

    Aspergillus niger is a filamentous ascomycete fungus that is ubiquitous in the environment and has been implicated in opportunistic infections of humans. In addition to its role as an opportunistic human pathogen, A. niger is economically important as a fermentation organism used for the production of citric acid. Industrial citric acid production by A. niger represents one of the most efficient, highest yield bioprocesses in use currently by industry. The genome size of A. niger is estimated to be between 35.5 and 38.5 megabases (Mb) divided among eight chromosomes/linkage groups that vary in size from 3.5 - 6.6 Mb. Currently, there are three independent A. niger genome projects, an indication of the economic importance of this organism. The rich amount of data resulting from these multiple A. niger genome sequences will be used for basic and applied research programs applicable to fermentation process development, morphology and pathogenicity.

  19. Biosorption potency of Aspergillus niger for removal of chromium (VI).

    PubMed

    Srivastava, Shaili; Thakur, Indu Shekhar

    2006-09-01

    Aspergillus niger isolated from soil and effluent of leather tanning mills had higher activity to remove chromium. The potency of Aspergillus niger was evaluated in shake flask culture by absorption of chromium at pH 6 and temperature 30 degrees C. The results of the study indicated removal of more than 75% chromium by Aspergillus niger determined by diphenylcarbazide colorimetric assay and atomic absorption spectrophotometry after 7 days. Study of microbial Cr(VI) reduction and identification of reduction intermediates has been hindered by the lack of analytical techniques that can identify the oxidation state with subcellular spatial resolution. Therefore, removal of chromium was further substantiated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), which indicated an accumulation of chromium in the fungal mycelium. PMID:16874547

  20. Dual genome microarray: Fusarium verticillioides and Aspergillus flavus gene expression in co-culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins produced by Aspergillus flavus, and fumonisins produced by Fusarium verticillioides, are prominent among the mycotoxins associated with economic losses to the maize grain industry worldwide. F. verticillioides is also recognized as a systemic endophyte of maize that prevents opportunisti...

  1. Evaluation of Atoxigenic Strains of Aspergillus flavus as Potential Biocontrol Agents for Aflatoxin in Maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination resulting from maize infection by Aspergillus flavus is both an economic concern and public health concern. Therefore, strategies for controlling maize contamination are being investigated. Abilities of 11 naturally occurring atoxigenic strains in Nigeria to reduce aflatox...

  2. Gene Profiling for Studying the Mechanism of Aflatoxin Biosynthesis in Aspergillus flavus and A. parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic and carcinogenic polyketide metabolites produced by certain fungal species, including Aspergillus flavus and A. parasiticus. Because many internal and external factors, such as nutrition and environment affect aflatoxin biosynthesis, we have analyzed the transcriptome of A. fla...

  3. Twenty-four microsatellite markers for the aflatoxin-producing fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus infects both plants and humans and contaminates diverse agricultural crops with aflatoxins, highly carcinogenic fungal metabolites. We describe 24 microsatellite markers developed to assess genetic diversity and recombination within and between three vegetative compatibility group...

  4. Recombination, balancing selection and geographic subdivision among worldwide populations of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a global agent of aflatoxin contamination of economically important crops such as corn, peanuts, and cottonseed. Extensive studies have elucidated the biochemical and regulatory mechanisms of aflatoxin production, but basic knowledge of the evolutionary processes that maintain ...

  5. Flocculation behavior and mechanism of bioflocculant produced by Aspergillus flavus.

    PubMed

    Aljuboori, Ahmad H Rajab; Idris, Azni; Al-joubory, Hamid Hussain Rijab; Uemura, Yoshimitsu; Ibn Abubakar, B S U

    2015-03-01

    In this study, the flocculation behavior and mechanism of a cation-independent bioflocculant IH-7 produced by Aspergillus flavus were investigated. Results showed 91.6% was the lowest flocculating rate recorded by IH-7 (0.5 mg L(-1)) at pH range 4-8. Moreover, IH-7 showed better flocculation performance than polyaluminum chloride (PAC) at a wide range of flocculant concentration (0.06-25 mg L(-1)), temperature (5-45 °C) and salinity (10-60% w/w). The current study found that cation addition did not significantly enhance the flocculating rate and IH-7 is a positively charged bioflocculant. These findings suggest that charge neutralization is the main flocculation mechanism of IH-7 bioflocculant. IH-7 was significantly used to flocculate different types of suspended solids such as activated carbons, kaolin clays, soil solids and yeast cells. PMID:25560664

  6. Characterization of an Aspergillus flavus alkaline protease and its role in the infection of maize kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 33 kDa protein present in Aspergillus flavus infected maize embryo tissue was identified as a fungal alkaline protease (ALP). This protein became one of the major extracellular proteins of A. flavus in potato dextrose broth medium cultural filtrate after 3 days, but was expressed at low levels or ...

  7. Green Fluorescent Protein as a Reporter To Monitor Gene Expression and Food Colonization by Aspergillus flavus

    PubMed Central

    Du, Wanglei; Huang, Zhengyu; Flaherty, Joseph E.; Wells, Kevin; Payne, Gary A.

    1999-01-01

    Transformants of Aspergillus flavus containing the Aequorea victoria gfp gene fused to a viral promoter or the promoter region and 483 bp of the coding region of A. flavus aflR expressed green fluorescence detectable without a microscope or filters. Expression of green fluorescent protein fluorescence was correlated with resistance to aflatoxin accumulation in five corn genotypes inoculated with these transformants. PMID:9925624

  8. The release of the Aspergillus flavus whole genome sequence for public access

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are produced by Aspergillus flavus and A. parasiticus. These toxic and carcinogenic compounds contaminate pre-harvest agricultural crops in the field and post-harvest grains during storage. In order to reduce and eliminate aflatoxin contamination of food and feed, Aspergilllus flavus wh...

  9. Identification of hydrolytic activities expressed by Aspergillus flavus grown on cotton carpel tissue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus secreted at least two endoxylanase activities, two esterase activities and a pectolytic activity when grown on a medium containing cotton carpel tissue as a sole carbon source. A concentrated sample of A. flavus growth medium (6-day) was subjected to gel filtration chromatography...

  10. Integrated database for identifying candate genes for Aspergillus flavus resistance in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus Link:Fr, an opportunistic fungus that produces aflatoxin, is pathogenic to maize and other oilseed crops. Aflatoxin is a potent carcinogen, and its presence markedly reduces the value of grain. Understanding and enhancing host resistance to A. flavus infection and/or subsequent af...

  11. IDENTIFICATION OF MAIZE KERNEL ENDOSPERM PROTEINS ASSOCIATED WITH RESISTANCE TO AFLATOXIN CONTAMINATION BY ASPERGILLUS FLAVUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogens produced mainly by Aspergillus flavus during infection of susceptible crops, such as maize (Zea mays L.). Previously, embryo proteins from maize genotypes resistant or susceptible to A. flavus infection were compared using proteomics and resistance-associated proteins wer...

  12. Recombination and lineage-specific gene loss in the aflatoxin gene cluster of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins produced by Aspergillus flavus are potent carcinogens that contaminate agricultural crops. Recent efforts to reduce aflatoxin concentrations in crops have focused on biological control using nonaflatoxigenic A. flavus strains AF36 (= NRRL 18543) and NRRL 21882 (the active component of af...

  13. Developing an in vitro method to assess aflatoxin biosynthesis suppression in Aspergillus flavus through RNAi technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The soil-inhabitant fungus Aspergillus flavus is consistently associated with agronomical fields, where it promptly colonizes important crops such as corn (Zea mays) and peanuts (Arachis hypogaea). The consumption of A. flavus-contaminated of food grains poses a potential threat for human and animal...

  14. Effect of sexual recombination on population diversity in aflatoxin production by Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is the major producer of carcinogenic aflatoxins (AFs) in crops worldwide. Recent efforts to reduce AF concentrations in crops have focused on the use of two non-aflatoxigenic A. flavus strains, AF36 and NRRL 21882 (Afla-Guard), as biological control agents. These products are a...

  15. A GOOD ENDOPHYTE OF MAIZE: ACREMONIUM ZEAE ANTIBIOTICS INHIBITORY TO ASPERGILLUS FLAVUS AND FUSARIUM VERTICILLIOIDES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The maize endophyte Acremonium zeae Gams and Sumner is antagonistic to kernel rotting and mycotoxin producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for antagonism and interferes with A. flavus infection and aflatoxin contamination of preharvest maize kernels. Chemi...

  16. EST Profiling for Elucidation of Molecular Regulation of Aflatoxin bBiosynthesis in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic and carcinogenic polyketide metabolites produced by fungal species, including Aspergillus flavus and A. parasiticus. Many internal and external factors, such as nutrition and environment, affect aflatoxin biosynthesis. A. flavus EST has been carried out and a microarray has be...

  17. Aspergillus Flavus/Aflatoxin Occurrence and Expression of Aflatoxin Biosynthesis Genes in Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins (AF) are carcinogenic metabolites produced by several species of Aspergillus, including A. flavus. Although A. flavus is readily isolated from environmental samples, soil and plant material are considered the natural habitat of this fungus. Studies were conducted on a Dundee silt loam to ...

  18. The potential role of oxidative stress in Aspergillus flavus survivability and aflatoxin biosynthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination of food and feed occurs due to growth of Aspergillus flavus. This poses a serious health risk because of aflatoxin’s toxic and carcinogenic properties which negatively impact human and livestock health. Colonization and subsequent aflatoxin production by A. flavus is typicall...

  19. Volatile profiles of toxigenic and non-toxigenic Aspergillus flavus using SPME for solid phase extraction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxigenic and atoxigenic strains of Aspergillus flavus were grown on potato dextrose agar (PDA) and wetted sterile, cracked corn for 21 and 14 days, respectively. Volatile compounds produced by A. flavus, as well as those present in the PDA controls and sterile cracked corn, were collected using sol...

  20. Formation of Aspergillus flavus sclerotia on corn grown under different drought stress conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a major producer of carcinogenic aflatoxins worldwide in corn, peanuts, tree nuts, cottonseed, spices and other crops. Many countries have strict limits on the amount of aflatoxins permitted in human commodities and animal feed. Sclerotia produced by A. flavus serve several f...

  1. Molecular markers associated with resistance to Aspergillus flavus in maize: QTL and discriminant analyses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination of maize (Zea mays L.) grain caused by Aspergillus flavus is a serious health hazard to animals and humans. Resistance to infection by A. flavus is poorly understood. The objectives of this investigation were to identify potential candidate markers associated with resistance ...

  2. NON-TOXIGENIC ASPERGILLUS FLAVUS ISOLATES FOR REDUCING AFLATOXIN IN MISSISSIPPI DELTA CORN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential for two non-toxigenic isolates of Aspergillus flavus CT3 and K49 isolated from the Mississippi Delta to reduce aflatoxin contamination of corn was assessed in a field study. These two isolates exhibited comparable growth and aggressiveness as the toxigenic A. flavus isolate F3W4. The...

  3. Genetic Isolation among Sympatric Vegetative Compatibility Groups of the aflatoxin-producing fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus, fungal pathogen of animals and both wild and economically important plants, is most recognized for producing aflatoxin, a cancer-causing secondary metabolite, that contaminates food and animal feed globally. A. flavus is asexual and has a vegetative incompatibility system that li...

  4. Aspergillus flavus Genomic Data Mining Provides Clues for Its Use in Producing Biobased Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is notorious for its ability to produce aflatoxins. It is also an opportunistic pathogen that infects plants, animals and human beings. The ability to survive in the natural environment, living on plant tissues (leaves or stalks), live or dead insects make A. flavus a ubiquitous...

  5. A two-dimenstional proteome reference map of the aflatoxigenic fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The description of A. flavus proteome provides insight into its basic biology and a basis for its future proteomic investigations. Aspergillus flavus is a widely distributed fungal pathogen that infects important agricultural commodities (maize, tree nuts, etc.) and contaminates them with aflatoxin...

  6. The launch of the Aspergillus flavus genome browser and limited release of whole genome sequence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are produced by Aspergillus flavus and A. parasiticus. These toxic and carcinogenic compounds contaminate pre-harvest agricultural crops in the field and post-harvest grains during storage. In order to reduce and eliminate aflatoxin contamination of food and feed, Aspergilllus flavus wh...

  7. Sexual recombination and the possibility of cryptic heterokaryosis in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus infects both plants and animals and is of toxicological importance due to its production of aflatoxins (AFs). Recent efforts to reduce AF concentrations have focused on the use of the biocontrols AF36 and Afla-Guard®, both of which contain nonaflatoxigenic A. flavus strains as an ...

  8. Aspergillus flavus Blast2GO gene ontology database: elevated growth temperature alters amino acid metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The availability of a representative gene ontology (GO) database is a prerequisite for a successful functional genomics study. Using online Blast2GO resources we constructed a GO database of Aspergillus flavus. Of the predicted total 13,485 A. flavus genes 8,987 were annotated with GO terms. The mea...

  9. Sexual reproduction in Aspergillus flavus sclerotia: acquisition of novel alleles from soil populations and uniparental mitochondrial inheritance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus colonizes agricultural commodities worldwide and contaminates them with carcinogenic aflatoxins. The high genetic diversity of A. flavus populations is largely due to sexual reproduction characterized by the formation of ascospore-bearing ascocarps embedded within sclerotia. A. ...

  10. Community structure of Aspergillus flavus and persistence of the atoxigenic strain A flavus AF36 in applied fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic and carcinogenic metabolites produced by several fungi in Aspergillus Section Flavi that frequently contaminate crops. Aflatoxins impact the value of crops. The use of atoxigenic strains of A. flavus to displace aflatoxin producers is a proven method to reduce aflatoxin contamin...

  11. Glucoamylase production by a newly isolated strain of Aspergillus niger

    SciTech Connect

    Sinkar, V.P.; Lewis, N.F.

    1982-01-01

    Glucoamylase production by Aspergillus niger 57 was studied in complex and synthetic media under stationary vs. submerged conditions. Stationary cultivation resulted in significantly greater yields than did submerged culture. Crude enzyme activity was optimum at 60 degrees and pH 4.0.

  12. rmtA, encoding a putative anginine methyltransferase, regulates secondary metabolism and development in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is found colonizing numerous oil seed crops such as corn, peanuts, sorghum, treenuts and cotton worldwide, contaminating them with aflatoxin and other harmful potent toxins. In the phylogenetically related model fungus Aspergillus nidulans, the methyltransferase, RmtA, has been de...

  13. Non-aflatoxigenic Aspergillus flavus isolates reduce aflatoxins, cyclopiazonic acid and fumonisin in corn (maize)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus strains vary widely in their production of aflatoxins and cyclopiazonic acid (CPA). A total of 500 Aspergillus strains isolated from a variety of sources showed 16.4% were negative for both aflatoxin and CPA, 41.3% were positive for both mycotoxins, 13.0% were positive only fo...

  14. NsdC and NsdD affect Aspergillus flavus morphogenesis and aflatoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transcription factors NsdC and NsdD have been shown to be necessary for sexual development in Aspergillus nidulans. Herein we examine the role of these proteins in development and aflatoxin production of the agriculturally important, aflatoxin-producing fungus, Aspergillus flavus. We found tha...

  15. Sexual reproduction influences aflatoxin chemotype diversity in worldwide populations of Aspergillus flavus and A. parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic polyketides produced by several Aspergillus species that contaminate food crops worldwide. Aspergillus flavus and A. parasiticus are the most common agents of aflatoxin contamination of oil-rich crops. The genes involved in aflatoxin biosynthesis are clustered and convert acetat...

  16. RNA interference reduces aflatoxin accumulation by Aspergillus flavus in peanut seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are among the most powerful carcinogens in nature. They are produced by the fungal pathogen Aspergillus flavus Link and other Aspergillus species. Aflatoxins accumulate in many crops, including rice, wheat, oats, pecans, pistachios, soybean, cassava, almonds, peanuts, beans, corn and cot...

  17. Population genetics as a tool for understanding toxigenesis in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species in Aspergillus section Flavi commonly infect agricultural staples such as corn, peanuts, cottonseed, and tree nuts and produce an array of mycotoxins, the most potent of which is aflatoxin. Aspergillus flavus is the dominant aflatoxin-producing species in the majority of crops. Populations...

  18. Lack of aflatoxin production by Aspergillus flavus on a resistant peanut line is associated with delayed expression of aflatoxin genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins, produced by Aspergillus flavus and Aspergillus parasiticus, are the most toxic fungal secondary metabolites and the most potent carcinogens that contaminate agricultural commodities such as peanuts, cotton and corn. Understanding the underlying mechanisms of crop resistance to fungal in...

  19. Development and Evaluation of an Affymetrix array for Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-species Affymetrix GeneChip array was developed to study development, metabolism and pathogenicity of A. flavus. This chip based on the whole genome sequence of A. flavus, contains 13,000 A. flavus genes, 8,000 maize genes and 25 human and mouse innate immune response genes, as well as the ...

  20. Decontamination of Aspergillus flavus and Aspergillus parasiticus spores on hazelnuts via atmospheric pressure fluidized bed plasma reactor.

    PubMed

    Dasan, Beyhan Gunaydin; Mutlu, Mehmet; Boyaci, Ismail Hakki

    2016-01-01

    In this study, an atmospheric pressure fluidized bed plasma (APFBP) system was designed and its decontamination effect on aflatoxigenic fungi (Aspergillus flavus and Aspergillus parasiticus) on the surface of hazelnuts was investigated. Hazelnuts were artificially contaminated with A. flavus and A. parasiticus and then were treated with dry air plasma for up to 5min in the APFBP system at various plasma parameters. Significant reductions of 4.50 log (cfu/g) in A. flavus and 4.19 log (cfu/g) in A. parasiticus were achieved after 5min treatments at 100% V - 25kHz (655W) by using dry air as the plasma forming gas. The decontamination effect of APFBP on A. flavus and A. parasiticus spores inoculated on hazelnuts was increased with the applied reference voltage and the frequency. No change or slight reductions were observed in A. flavus and A. parasiticus load during the storage of plasma treated hazelnuts whereas on the control samples fungi continued to grow under storage conditions (30days at 25°C). Temperature change on hazelnut surfaces in the range between 35 and 90°C was monitored with a thermal camera, and it was demonstrated that the temperature increase taking place during plasma treatment did not have a lethal effect on A. flavus and A. parasiticus spores. The damage caused by APFBP treatment on Aspergillus spp. spores was also observed by scanning electron microscopy. PMID:26398284

  1. Inhibition of Aflatoxin Production of Aspergillus flavus by Lactobacillus casei

    PubMed Central

    Chang, Injeong

    2007-01-01

    Lactobacillus casei KC-324 was tested for its ability to inhibit aflatoxin production and mycelial growth of Aspergillus flavus ATCC 15517 in liquid culture. Aflatoxin B1 biosynthesis and mycelial growth were inhibited in both simultaneous culture and individual antagonism assays,suggesting that the inhibitory activity was due to extracellular metabolites produced in cell-free supernatant fluids of the cultured broth of L. casei KC-324. In cell-free supernatant fluids of all media tested,deMan,Rogosa and Sharpe broth,potato dextrose broth,and Czapek-Dox broth + 1% yeast extract showed higher antiaflatoxigenic activity. In these case, fungal growths, however, was not affected as measured by mycelial dry weight. The antiaflatoxigenic metabolites from L. casei KC-324 were produced over wide range of temperatures between 25℃ and 37℃. However, these metabolites were not thermostable since the inhibitory activity of the supernatant was inactivated within 30 minutes at 100℃ and 121℃. The inhibitory activity was not influenced by changing pH of supernatant between 4 and 10. However,the antiaflatoxigenic activity was slightly reduced at pH 10. PMID:24015075

  2. Aspergillus flavus-Induced Brain Abscess in an Immunocompetent Child

    PubMed Central

    Al-Maskari, Nawal; Hussain, Ibrahim; Jumaa, Suleiman; Al-Shail, Essam A.

    2016-01-01

    Intracranial aspergillosis is an extremely rare manifestation of invasive aspergillosis in immunocompetent children and is associated with high morbidity and mortality. We report a 12-year-old immunocompetent male child who was referred to the King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia, in May 2010 after a sudden-onset headache and loss of consciousness. Brain imaging revealed a large right space-occupying occipital lesion and the patient underwent a craniotomy and resection. Histopathology of the lesion revealed necrotising granulomatous fungal encephalitis with many hyphae engulfed by multinucleated giant histiocytes. Two days later, a computed tomography scan showed debulking of the fungal mass and the patient was discharged on oral voriconazole. However, imaging at a six-week follow-up showed progression of the abnormality. A residual or persistent fungal brain lesion was suspected. Further neurosurgical resection of the lesion was performed and cultures showed growth of Aspergillus flavus. The patient was treated successfully with antifungal therapy over the following two years. PMID:27226920

  3. Production of chitin deacetylase by Aspergillus flavus in submerged conditions.

    PubMed

    Narayanan, Karthik; Parameswaran, Binod; Pandey, Ashok

    2016-07-01

    Chitosan is a biopolymer obtained by deacetylation of chitin and has been proven to have various applications in industry and biomedicine. Deacetylation of chitin using the enzyme chitin deacetylase (CDA) is favorable in comparison to the hazardous chemical method involving strong alkali and high temperature. A fungal strain producing CDA was isolated from environmental samples collected from coastal regions of South Kerala, India. It was identified as Aspergillus flavus by morphological characteristics and ITS DNA analysis. Nutritional requirement for maximum production of CDA under submerged condition was optimized using statistical methods including Plackett-Burman and response surface methodology central composite design. A 5.98-fold enhancement in CDA production was attained in shake flasks when the fermentation process parameters were used at their optimum levels. The highest CDA activity was 57.69 ± 1.68 U under optimized bioprocess conditions that included 30 g L(-1) glucose, 40 g L(-1) yeast extract, 15 g L(-1) peptone, and 7 g L(-1) MgCl2 at initial media pH of 7 and incubation temperature of 32°C after 48 hr of incubation, while the unoptimized basal medium yielded 9.64 ± 2.04 U. PMID:26474347

  4. Toward elucidation of genetic and functional genetic mechanisms in corn host resistance to Aspergillus flavus infection and aflatoxin contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic mycotoxins produced by the fungus Aspergillus flavus. Aflatoxin contamination in pre-harvest corn profusely happens when heat and drought field conditions favor A. flavus colonization. Commercial corn hybrids are generally susceptible to A. flavus infection. An ideal cont...

  5. Production of extremophilic bacterial cellulase enzymes in aspergillus niger.

    SciTech Connect

    Gladden, John Michael

    2013-09-01

    Enzymes can be used to catalyze a myriad of chemical reactions and are a cornerstone in the biotechnology industry. Enzymes have a wide range of uses, ranging from medicine with the production of pharmaceuticals to energy were they are applied to biofuel production. However, it is difficult to produce large quantities of enzymes, especially if they are non-native to the production host. Fortunately, filamentous fungi, such as Aspergillus niger, are broadly used in industry and show great potential for use a heterologous enzyme production hosts. Here, we present work outlining an effort to engineer A. niger to produce thermophilic bacterial cellulases relevant to lignocellulosic biofuel production.

  6. 77 FR 14287 - Aspergillus flavus AF36; Amendment to an Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ...This regulation amends the existing temporary tolerance exemption for Aspergillus flavus AF36 by establishing a permanent exemption from the requirement of a tolerance for residues of the microbial pesticide, Aspergillus flavus AF36, in or on pistachio when applied as an antifungal agent and used in accordance with good agricultural practices. On behalf of the Arizona Cotton Research and......

  7. RNA sequencing of an nsdC mutant reveals global regulation of secondary metabolic gene clusters in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The zinc finger transcription factor nsdC is required for both sexual development and aflatoxin production in the saprophytic fungus Aspergillus flavus. While previous work with an nsdC knockout mutant was conducted in Aspergillus nidulans and A. flavus strain 3357, here we demonstrate perturbations...

  8. Purification and immobilization of Aspergillus niger. beta. -xylosidase

    SciTech Connect

    Oguntimein, G.B.; Reilly, P.J.

    1980-01-01

    ..beta..-Xylosidase from a commercial Aspergillus niger preparation was purified by differential ammonium sulfate precipitation and either gel permeation or cation exchange chromatography, giving 16-fold purification in 32% yield for the first technique or 27-fold purification in 19% yield for the second. Enzyme prepared by this method was immobilized to 10 different carriers, but only when it was bound to alumina with TiCl/sub 4/ and to alkylamine porous silica with glutaraldehyde were substantial efficiencies and stabilities achieved.

  9. Structure elucidation of metabolites of swertiamarin produced by Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Jun, Chang; Xue-Ming, Zhao; Chang-Xiao, Liu; Tie-Jun, Zhang

    2008-04-01

    The in vitro metabolism of swertiamarin was carried out in preparative scale using the fungus Aspergillus niger and the metabolites were isolated by semi-preparative HPLC combined with liquid-liquid extraction. Two metabolites, erythrocentaurin and one new compound were obtained and identified by 1H, 13C and 2D NMR and high resolution MS. The anti-inflammatory activity of the novel metabolite was tested and compared with that of swertiamarin in a mice model.

  10. Analytical and computational approaches to define the Aspergillus niger secretome

    SciTech Connect

    Tsang, Adrian; Butler, Gregory D.; Powlowski, Justin; Panisko, Ellen A.; Baker, Scott E.

    2009-03-01

    We used computational and mass spectrometric approaches to characterize the Aspergillus niger secretome. The 11,200 gene models predicted in the genome of A. niger strain ATCC 1015 were the data source for the analysis. Depending on the computational methods used, 691 to 881 proteins were predicted to be secreted proteins. We cultured A. niger in six different media and analyzed the extracellular proteins produced using mass spectrometry. A total of 222 proteins were identified, with 39 proteins expressed under all six conditions and 74 proteins expressed under only one condition. The secreted proteins identified by mass spectrometry were used to guide the correction of about 20 gene models. Additional analysis focused on extracellular enzymes of interest for biomass processing. Of the 63 glycoside hydrolases predicted to be capable of hydrolyzing cellulose, hemicellulose or pectin, 94% of the exo-acting enzymes and only 18% of the endo-acting enzymes were experimentally detected.

  11. Hyperspectral imagery for observing spectral signature change in Aspergillus flavus

    NASA Astrophysics Data System (ADS)

    DiCrispino, Kevin; Yao, Haibo; Hruska, Zuzana; Brabham, Kori; Lewis, David; Beach, Jim; Brown, Robert L.; Cleveland, Thomas E.

    2005-11-01

    Aflatoxin contaminated corn is dangerous for domestic animals when used as feed and cause liver cancer when consumed by human beings. Therefore, the ability to detect A. flavus and its toxic metabolite, aflatoxin, is important. The objective of this study is to measure A. flavus growth using hyperspectral technology and develop spectral signatures for A. flavus. Based on the research group's previous experiments using hyperspectral imaging techniques, it has been confirmed that the spectral signature of A. flavus is unique and readily identifiable against any background or surrounding surface and among other fungal strains. This study focused on observing changes in the A. flavus spectral signature over an eight-day growth period. The study used a visible-near-infrared hyperspectral image system for data acquisition. This image system uses focal plane pushbroom scanning for high spatial and high spectral resolution imaging. Procedures previously developed by the research group were used for image calibration and image processing. The results showed that while A. flavus gradually progressed along the experiment timeline, the day-to-day surface reflectance of A. flavus displayed significant difference in discreet regions of the wavelength spectrum. External disturbance due to environmental changes also altered the growth and subsequently changed the reflectance patterns of A. flavus.

  12. The effect of 2-phenylethanol treatment on Aspergillus flavus transcriptome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pichia anomalais, which produces the antimicrobial volatile 2-phenylethanol (2-PE), is effective in reducing A. flavus growth and aflatoxin production. We treated A. flavus NRRL3357 with 2-PE and analyzed changes in the transcriptomic profiles at different stages of fungal growth. RNA-Seq reads from...

  13. Functional Genomic Analysis of Aspergillus flavus Interacting with Resistant and Susceptible Peanut

    PubMed Central

    Wang, Houmiao; Lei, Yong; Yan, Liying; Wan, Liyun; Ren, Xiaoping; Chen, Silong; Dai, Xiaofeng; Guo, Wei; Jiang, Huifang; Liao, Boshou

    2016-01-01

    In the Aspergillus flavus (A. flavus)–peanut pathosystem, development and metabolism of the fungus directly influence aflatoxin contamination. To comprehensively understand the molecular mechanism of A. flavus interaction with peanut, RNA-seq was used for global transcriptome profiling of A. flavus during interaction with resistant and susceptible peanut genotypes. In total, 67.46 Gb of high-quality bases were generated for A. flavus-resistant (af_R) and -susceptible peanut (af_S) at one (T1), three (T2) and seven (T3) days post-inoculation. The uniquely mapped reads to A. flavus reference genome in the libraries of af_R and af_S at T2 and T3 were subjected to further analysis, with more than 72% of all obtained genes expressed in the eight libraries. Comparison of expression levels both af_R vs. af_S and T2 vs. T3 uncovered 1926 differentially expressed genes (DEGs). DEGs associated with mycelial growth, conidial development and aflatoxin biosynthesis were up-regulated in af_S compared with af_R, implying that A. flavus mycelia more easily penetrate and produce much more aflatoxin in susceptible than in resistant peanut. Our results serve as a foundation for understanding the molecular mechanisms of aflatoxin production differences between A. flavus-R and -S peanut, and offer new clues to manage aflatoxin contamination in crops. PMID:26891328

  14. Transcriptome analysis of Aspergillus niger grown on sugarcane bagasse

    PubMed Central

    2011-01-01

    Background Considering that the costs of cellulases and hemicellulases contribute substantially to the price of bioethanol, new studies aimed at understanding and improving cellulase efficiency and productivity are of paramount importance. Aspergillus niger has been shown to produce a wide spectrum of polysaccharide hydrolytic enzymes. To understand how to improve enzymatic cocktails that can hydrolyze pretreated sugarcane bagasse, we used a genomics approach to investigate which genes and pathways are transcriptionally modulated during growth of A. niger on steam-exploded sugarcane bagasse (SEB). Results Herein we report the main cellulase- and hemicellulase-encoding genes with increased expression during growth on SEB. We also sought to determine whether the mRNA accumulation of several SEB-induced genes encoding putative transporters is induced by xylose and dependent on glucose. We identified 18 (58% of A. niger predicted cellulases) and 21 (58% of A. niger predicted hemicellulases) cellulase- and hemicellulase-encoding genes, respectively, that were highly expressed during growth on SEB. Conclusions Degradation of sugarcane bagasse requires production of many different enzymes which are regulated by the type and complexity of the available substrate. Our presently reported work opens new possibilities for understanding sugarcane biomass saccharification by A. niger hydrolases and for the construction of more efficient enzymatic cocktails for second-generation bioethanol. PMID:22008461

  15. Mutagenesis and genetic characterisation of amylolytic Aspergillus niger.

    PubMed

    Shafique, Sobiya; Bajwa, Rukhsana; Shafique, Shazia

    2010-07-01

    Aspergillus niger FCBP-198 was genetically modified for its ability to reveal extra cellular alpha-amylase enzyme activity. From 76 efficient mutants isolated after ultraviolet (UV) irradiation, An-UV-5.6 was selected as the most efficient UV mutant, with 76.41 units mL(-1) of alpha-amylase activity compared to wild (34.45 units mL(-1)). In case of ethyl methane sulphonate (EMS), among 242 survivors, 74 were assayed quantitatively and An-Ch-4.7 was found to be the most competent, as it exhibited a three-fold increase in alpha-amylase activity (89.38 units mL(-1)) than the parental strain. Genetic relationships of the mutants of A. niger FCBP-198 were analysed with a randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Results obtained from the comparison between genotypes of A. niger FCBP-198 showed differences in the sizes and numbers of amplified fragments per primer for each isolate. The dendrogram showed that genotypes An-Ch-4.7 and An-Ch-4.2 were distinctly classified into one category, while the isolates An-UV-5.6, An-UV-5.1 and A. niger FCBP-198 have the nearest genetic relationship. The five isolates from A. niger FCBP-198 genotypes shared an average of 65% bands. PMID:19764004

  16. Volatile trans-2-hexenal a soybean aldehyde inhibits Aspergillus flavus growth and aflatoxin production in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trans-2-hexenal, a volatile aldehyde, is produced by soybean [Glycine max (L.) Merr] and other plants via the lipoxygenase pathway. In vitro tests showed it significantly (p< 0.001) reduced Aspergillus flavus germinating conidial viability at 10 µM, with approximately 95% viability reduction observ...

  17. Managing and Monitoring of Aspergillus flavus in Corn Using Bioplastic-based Formulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, we evaluated the feasibility of bioplastic-based formulations for delivering a non-aflatoxigenic strain of Aspergillus flavus and for monitoring Aspergilli with the final objective of controlling aflatoxin contamination in corn. Field application of inoculated bioplastic granules show...

  18. Hyperspectral image classification and development of fluorescence index for single corn kernels infected with Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic secondary metabolites predominantly produced by the fungi Aspergillus flavus and A. parasiticus. Aflatoxin contaminated corn is toxic to domestic animals when ingested in feed and is a known carcinogen associated with liver and lung cancer in humans. Consequently, aflatoxin leve...

  19. Aspergillus flavus whole genome and EST sequence releases and construction of homologous gene search blast server

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic and carcinogenic secondary metabolites. These compounds, produced by Aspergillus flavus and A. parasiticus, contaminate pre-harvest agricultural crops in the field and post-harvest grains during storage. In order to reduce and eliminate aflatoxin contamination of food and feed...

  20. Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress and future perspectives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The colonization of maize (Zea mays L.) and peanut (Arachis hypogaea L.) by the fungal pathogen Aspergillus flavus and A. parasiticus results in the contamination with carcinogenic mycotoxins known as aflatoxins leading to economic losses as well as a potential health threat to human. The interactio...

  1. Identification of novel metabolites from Aspergillus flavus by high resolution and multiple stage mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus contains more than 55 gene clusters which are predicted to encode proteins involved in secondary metabolite production. One of these, cluster 27, contains a polyketide synthase (pks27) gene which encodes a protein that is highly homologous to the aflatoxin cluster PKS. Comparative...

  2. Genome wide association mapping of Aspergillus flavus and aflatoxin accumulation resistance in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of maize with aflatoxin, produced by the fungus Aspergillus flavus, has severe health and economic consequences. Efforts to reduce aflatoxin accumulation in maize have focused on identifying and selecting germplasm with natural host resistance factors, and several maize lines with sign...

  3. Ear Rot, Aflatoxin Accumulation, and Fungal Biomass in Maize after Inoculation with Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin, a toxin produced by the fungus Aspergillus flavus Link:Fries, occurs naturally in maize (Zea mays L.). Aflatoxin is a potent human carcinogen and is toxic to livestock, pets, and wildlife. When contaminated with aflatoxin, the value of maize grain is markedly reduced. Eight germplasm l...

  4. Isolation of maize soil and rhizosphere bacteria with antagonistic activity against Aspergillus flavus and Fusarium verticillioides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial isolates from Mississippi maize field soil and maize rhizosphere samples were evaluated for their potential as biological control agents against Aspergillus flavus and Fusarium verticillioides. Isolated strains were screened for antagonistic activities in liquid co-culture against A. flav...

  5. Is rachis lignification a deterrent to Aspergillus flavus movement through the developing maize ear?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In previous research, the proteomes of the immature rachis of Aspergillus flavus resistant and susceptible maize inbreds were compared using differential-in-gel electrophoresis (DIGE). One of the proteins that was 66-fold more abundant in the resistant inbred MP313E than in the susceptible inbred S...

  6. The inhibitory effect of Bacillus megaterium on aflatoxin biosynthetic pathway gene expression in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is one of the major fungal mold that colonize peanut in the field and during storage. The impacts to human and animal health and to economy in agriculture and commerce are significant since this mould produces the most potent natural toxins, aflatoxins, which are carcinogenic, mut...

  7. Insights into sexual reproduction in Aspergillus flavus from variation in experimental crosses and natural populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus contaminates many important crops worldwide and is the major producer of aflatoxins, which are cancer-causing secondary metabolites. Biological control is the most effective means of reducing inoculum levels of detrimental aflatoxin-producing fungal pathogens in agricultural syst...

  8. Isolation and structural elucidation of acidic terpenoid phytoalexins in maize and their interactions with Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants use a variety of physical and chemical defenses in response to herbivory and pathogen attack. Infection of maize by the fungal pathogen Aspergillus flavus results in the accumulation of aflatoxins, which are among the most detrimental biogenic substances known to man. The majority of maize de...

  9. Intraspecific competition during infection by Aspergillus flavus is influenced by plant host species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Communities of Aspergillus flavus are composed of diverse genotypes that collectively influence incidence and severity of crop aflatoxin contamination. Isolates vary in competitive ability on maize, but empirical data on the extent to which host-specific influences determine outcomes of competition ...

  10. Genes differentially expressed by Aspergillus flavus strains after loss of aflatoxin production by serial transfers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic fungal secondary metabolites produced by Aspergillus flavus and other closely related species. Levels of aflatoxins in agricultural commodities are stringently regulated by many countries and thus aflatoxins are a major concern to both producers and consumers. A cluster...

  11. Crop rotation and soil temperature influence the community structure of Aspergillus flavus in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus, the most important cause of aflatoxin contamination has two major morphotypes commonly named S and L strains. Strain S isolates, on average, produce more aflatoxins than the strain L isolates. The S strain has been implicated as the primary causal agent of several contamination e...

  12. Aflatoxigenesis induced in Aspergillus flavus by oxidative stress and reduction by phenolic antioxidants from tree nuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almonds, pistachios, and walnuts grown in California have an aggregate value of over $3.3 billion, with a large proportion of the crop being exported. However, these tree nuts can be subject to contamination by aflatoxins, metabolites produced primarily by Aspergillus flavus and parasiticus, and im...

  13. RNA-seq analysis of an nsdC mutant in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The C2H2-type transcription factor NsdC (Never in Sexual Development C) has been shown to play a role in asexual development and secondary metabolite production in Aspergillus flavus, an agriculturally relevant, aflatoxin-producing species. The nsdC knoackout mutant demonstrates perturbed morphologi...

  14. Influence of Gene Expression on Variable Aflatoxin Production by Different Strains of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a globally distributed fungus. It causes disease in human and crop plants due to the production of numerous conidia dispersed by air movement and possibly by insects. The fungus is an economically important food contaminant because it produces the most potent natural carcinogen...

  15. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  16. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  17. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  18. Aspergillus flavus Aflatoxin Occurrence and Expression of Aflatoxin Biosynthesis Genes in Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The carcinogen, aflatoxin B1 (AFB1) produced by Aspergillus flavus, is a major food safety concern in crops. However, information on AFB1 occurrence in soil and crop residue is scarce. A series of experiments investigated the occurrence of AFB1 in soil and corn residues, and ascertained the ecology ...

  19. Identifying cotton (Gossypium hirsutum L.) genes induced in response to Aspergillus flavus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination in cottonseed, caused primarily by Aspergillus flavus, is a global concern in terms of food safety and economy. Current strategies to reduce the risk of aflatoxin contamination rely mostly upon biological control with non-aflatoxigenic strains and chemical control measures. ...

  20. CONSTRUCTION OF EXPRESSION CASSETTES TO CONFER RESISTANCE TO ASPERGILLUS FLAVUS IN COTTON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have been working to develop cotton that is resistant to the fungal pathogen Aspergillus flavus using a genetic engineering approach. Success of this project depends upon the identification of appropriate regulatory elements, as well as structural genes that can be linked to confer a new pathoge...

  1. Potential roles of environmental oxidative stress in aflatoxin production revealed in the Aspergillus flavus transcriptome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination caused by Aspergillus flavus infection in crops is known to be exacerbated primarily by abiotic stresses such as drought stress, and biotic stresses such as arthropod infestation. These stresses result in the production and accumulation of reactive oxygen species (ROS) in the...

  2. A maize lectin-like protein with antifungal activity against Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The filamentous fungus, Aspergillus flavus, causes an ear rot on maize and produces a mycotoxin, aflatoxin, in colonized maize kernels. Aflatoxins are carcinogenic to humans and animals upon ingestion. The presence of aflatoxins in food and feed is strictly regulated by several governmental agenci...

  3. Comparison of Inoculation Methods for Evaluating Maize for Resistance to Aspergillus flavus Infection and Aflatoxin Accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin, the most potent carcinogen found in nature, is produced by the fungus Aspergillus flavus. Aflatoxin occurs naturally in maize, Zea mays L. Growing maize hybrids with genetic resistance to aflatoxin contamination is generally considered a highly desirable way to reduce losses to aflatoxin....

  4. Evidence of extensive recombination in the aflatoxin gene cluster of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic compounds produced by several Aspergillus species that contaminate crops worldwide. A. flavus is the most common agent of aflatoxin contamination of corn, peanuts, cottonseed, figs and tree nuts in the US. Extensive studies have elucidated the biochemical and regulatory mechan...

  5. Evaluation of the atoxigenic Aspergillus flavus strain AF36 in pistachio orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was a...

  6. Aspergillus flavus Genomics as a Tool for Studying the Mechanism of Aflatoxin Formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a pathogen that infects plants, animals, and humans. It produces the most potent carcinogens, known as aflatoxins, when it infects agricultural crops. In order to devise strategies to control aflatoxin contamination of pre-harvest agricultural crops and post harvest grains du...

  7. New Monomeric Stilbenoids from Peanut (Arachis hypogaea) Seeds Challenged by an Aspergillus flavus Strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new stilbene derivatives have been isolated from peanut seeds challenged by an Aspergillus flavus strain, along with chiricanine B that has not been reported from peanuts, as well as a stilbenoid that has been known as a synthetic product. The structures of these new putative phytoalexins were d...

  8. Efficacy of water dispersible formulations of biocontrol strains of Aspergillus flavus for aflatoxin management in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field experiments were conducted in 2011 and 2012 to evaluate the efficacy of water dispersible granule (WDG) formulations of biocontrol strains of Aspergillus flavus in controlling aflatoxin contamination of corn. In 2011, when aflatoxin was present at very high levels, no WDG treatment provided s...

  9. Identification of atoxigenic Aspergillus flavus isolates to reduce aflatoxin contamination of maize in Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acute aflatoxin poisonings (aflatoxicosis) in Kenya have led to the deaths of several hundred people between 2004 and 2006. Etiology of contamination in the outbreak districts (Eastern Province) identified an unusual fungal community structure dominated by the highly toxigenic Aspergillus flavus S s...

  10. Testing the efficacy of eGFP-transformed Aspergillus flavus as biocontrol strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current biological control methods to prevent pre-harvest aflatoxin contamination of corn, cottonseed, and ground and tree nuts involve field inoculation of non-aflatoxigenic Aspergillus flavus. To date, the efficacy of this approach requires annual reapplication of the biocontrol agent. The reason ...

  11. Transcriptomic analysis reveal diverse responses to environmental oxidative stress in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought stress predisposes oilseed crops such as maize and peanut to infection by Aspergillus flavus resulting in their contamination with aflatoxins. Drought stress in plants results in the accumulation of reactive oxygen species (ROS) in their tissues, and these ROS have been shown to stimulate af...

  12. Inhibitory effects of gossypol-related compounds on growth of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gossypolone demonstrated growth inhibitory activity against Aspergillus flavus isolate AF13. Growth inhibition was concentration dependent, with a 50% effective dose of 90 µg gossypolone per mL of medium (165 µM). Growth inhibition levels of up to 95% were achieved with gossypolone concentrations ...

  13. Comparative transcriptome analysis of Aspergillus flavus isolates under different oxidative stresses and culture media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and aflatoxin contamination in the field are known to be influenced by numerous stress factors, particularly drought and heat stress. However, the purpose of aflatoxin production is unknown. Here, we report transcriptome analyses comprised of 282.6 Gb of sequencing data describing...

  14. Understanding the Genetics of Regulation of Aflatoxin Production and Aspergillus flavus Development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are polyketide-derived, toxic and carcinogenic secondary metabolites produced primarily by two fungal species, Aspergillus flavus and A. parasiticus, on crops such as corn, peanuts, cottonseed and treenuts. Regulatory guidelines issued by the U.S. Food and Drug Administration (FDA) preve...

  15. Application of biotechnology towards the enhancement of maize resistance to aflatoxin contamination by Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of maize with aflatoxins by the fungi Aspergillus flavus and A. parasiticus poses serious health hazards to humans and animals worldwide. This important fact and the regulations instituted in many countries to control the occurrence of aflatoxins in foods and feed have stimulated rese...

  16. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  17. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger may be safely used... the carbohydrase and cellulase enzyme product. (d) The additive is used or intended for use as...

  18. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  19. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  20. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  1. Contribution of arginase to manganese metabolism of Aspergillus niger.

    PubMed

    Keni, Sarita; Punekar, Narayan S

    2016-02-01

    Aspects of manganese metabolism during normal and acidogenic growth of Aspergillus niger were explored. Arginase from this fungus was a Mn[II]-enzyme. The contribution of the arginase protein towards A. niger manganese metabolism was investigated using arginase knockout (D-42) and arginase over-expressing (ΔXCA-29) strains of A. niger NCIM 565. The Mn[II] contents of various mycelial fractions were found in the order: D-42 strain < parent strain < ΔXCA-29 strain. While the soluble fraction forms 60% of the total mycelial Mn[II] content, arginase accounted for a significant fraction of this soluble Mn[II] pool. Changes in the arginase levels affected the absolute mycelial Mn[II] content but not its distribution in the various mycelial fractions. The A. niger mycelia harvested from acidogenic growth media contain substantially less Mn[II] as compared to those from normal growth media. Nevertheless, acidogenic mycelia harbor considerable Mn[II] levels and a functional arginase. Altered levels of mycelial arginase protein did not significantly influence citric acid production. The relevance of arginase to cellular Mn[II] pool and homeostasis was evaluated and the results suggest that arginase regulation could occur via manganese availability. PMID:26679485

  2. Biotransformations of organic compounds mediated by cultures of Aspergillus niger.

    PubMed

    Parshikov, Igor A; Woodling, Kellie A; Sutherland, John B

    2015-09-01

    Many different organic compounds may be converted by microbial biotransformation to high-value products for the chemical and pharmaceutical industries. This review summarizes the use of strains of Aspergillus niger, a well-known filamentous fungus used in numerous biotechnological processes, for biochemical transformations of organic compounds. The substrates transformed include monocyclic, bicyclic, and polycyclic aromatic hydrocarbons; azaarenes, epoxides, chlorinated hydrocarbons, and other aliphatic and aromatic compounds. The types of reactions performed by A. niger, although not unique to this species, are extremely diverse. They include hydroxylation, oxidation of various functional groups, reduction of double bonds, demethylation, sulfation, epoxide hydrolysis, dechlorination, ring cleavage, and conjugation. Some of the products may be useful as new investigational drugs or chemical intermediates. PMID:26162670

  3. Steady-state shear characteristics of Aspergillus niger broths

    SciTech Connect

    Svihla, C.K.; Dronawat, S.N.; Hanley, T.R.

    1995-12-31

    It can be difficult to obtain reliable rheological data for filamentous fermentation broths using conventional instruments. One common approach is to measure the torque drawn by an impeller rotating in the suspension. Many previous workers have assumed that the applicable shear rate in such a device is related to the impeller speed by a fluid-independent constant determined by calibration with Newtonian and non-Newtonian fluids. The rheology of Aspergillus niger broths have been characterized using the impeller viscometer approach. The changes in the broth rheology were measured, and used to interpret the growth of biomass and the evolution of the microorganism morphology.

  4. A survey on distribution and toxigenicity of Aspergillus flavus from indoor and outdoor hospital environments.

    PubMed

    Sepahvand, Asghar; Shams-Ghahfarokhi, Masoomeh; Allameh, Abdolamir; Jahanshiri, Zahra; Jamali, Mojdeh; Razzaghi-Abyaneh, Mehdi

    2011-11-01

    In the present study, genetic diversity and mycotoxin profiles of Aspergillus flavus isolated from air (indoors and outdoors), levels (surfaces), and soils of five hospitals in Southwest Iran were examined. From a total of 146 Aspergillus colonies, 63 isolates were finally identified as A. flavus by a combination of colony morphology, microscopic criteria, and mycotoxin profiles. No Aspergillus parasiticus was isolated from examined samples. Chromatographic analyses of A. flavus isolates cultured on yeast extract-sucrose broth by tip culture method showed that approximately 10% and 45% of the isolates were able to produce aflatoxin B(1) (AFB(1)) and cyclopiazonic acid (CPA), respectively. Around 40% of the isolates produced sclerotia on Czapek-Dox agar. The isolates were classified into four chemotypes based on the ability to produce AF and CPA that majority of them (55.5%) belonged to chemotype IV comprising non-mycotoxigenic isolates. Random amplified polymorphic DNA (RAPD) profiles generated by a combination of four selected primers were used to assess genetic relatedness of 16 selected toxigenic and non-toxigenic isolates. The resulting dendrogram demonstrated the formation of two separate clusters for the A. flavus comprised both mycotoxigenic and non-toxigenic isolates in a random distribution. The obtained results in this study showed that RAPD profiling is a promising and efficient tool to determine intra-specific genetic variation among A. flavus populations from hospital environments. A. flavus isolates, either toxigenic or non-toxigenic, should be considered as potential threats for hospitalized patients due to their obvious role in the etiology of nosocomial aspergillosis. PMID:22083786

  5. Aspergillus flavus and fusarium verticillioides induce tissue specific gene expression of PRms and UGT in maize kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and Fusarium verticillioides are fungal pathogens capable of colonizing maize kernels and contaminating them with mycotoxins. Development of effective control strategies is extremely difficult because pathogenesis and host response remain poorly understood. In this study, we monit...

  6. Sequence of host contact influences the outcome of competition among Aspergillus flavus isolates during host tissue invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of aflatoxin contamination by Aspergillus flavus is achieved by competitive exclusion of aflatoxin producers by atoxigenic strains. However, factors dictating the extent to which competitive displacement occurs during host infection are unknown. The role of preemptive exclusion in...

  7. Aspergillus flavus diversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humans and animals are exposed to aflatoxins, toxic carcinogenic fungal metabolites, through consumption of contaminated food and feed. Aspergillus flavus, the primary causal agent of crop aflatoxin contamination, is composed of phenotypically and genotypically diverse vegetative compatibility group...

  8. Aspergillus flavus and Fusariumverticillioides Induce Tissue Specific Gene Expression of PRms and UGT in Maize Seed before Fungal Colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and Fusariumverticillioides are fungal pathogens that colonize maize seeds and contaminate them with mycotoxins. To investigate the plant microbe interactions, we conducted histological and molecular studies to characterize the internal colonization of maize seed by the two fungal...

  9. Effect of sexual recombination on population diversity in aflatoxin production by Aspergillus flavus and evidence for cryptic heterokaryosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is the major producer of carcinogenic aflatoxins (AFs) in crops worldwide. Natural populations of A. flavus show tremendous variation in AF production, some of which can be attributed to environmental conditions, differential regulation of the AF biosynthetic pathway, and deletio...

  10. Aspergillus flavus Genomics for Development of Strategies to Interrupt Aflatoxin Formation and Discovery of Fungal Enzymes for Biofuel Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus produces toxic and the most carcinogenic mycotoxins, the aflatoxins. The primary objectives of our A. flavus genomics program are to reduce and eliminate aflatoxin contamination in food and feed and control fungal infection in preharvest crops such as corn, cotton, peanut and tre...

  11. The role of Aspergillus flavus veA in the production of extracellular proteins during growth on starch substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aflatoxin-producer and opportunistic plant pathogenic, filamentous fungus Aspergillus flavus is responsible for the contamination of corn and other important agricultural commodities. In order to obtain nutrients from the host A. flavus produces a variety of extracellular hydrolytic enzymes. Int...

  12. Elucidation of veA Dependent Genes Associated with Aflatoxin and Sclerotial Production in Aspergillus flavus by Functional Genomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aflatoxin-producing fungi, Aspergillus flavus and A. parasiticus, form structures called sclerotia that allow for survival under adverse conditions. Deletion of the veA gene in A. flavus and A. parasiticus blocks production of aflatoxin, as well as sclerotial formation. We used microarray tech...

  13. Toxigenic Aspergillus flavus and other fungi of public health concern in food and organic matter in southwest Nigeria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six Aspergillus flavus isolates out of 17 fungal isolates were sampled from diverse food and organic matter in southwest Nigeria. All the A. flavus samples produced aflatoxin and cyclopiazonic acid. These six isolates constitute a ready mycobank of toxigenic species for analytical research involving...

  14. PR10 expression in maize and its effect on host resistance against Aspergillus flavus infection and aflatoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays L.) is a major crop susceptible to Aspergillus flavus infection and subsequent contamination with aflatoxins, the potent carcinogenic secondary metabolites of the fungus. Protein profiles of maize genotypes resistant and susceptible to A. flavus infection and/or aflatoxin contaminati...

  15. The master transcription factor MtfA governs aflatoxin production, morphological development, and pathogenicity in the fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus produces a variety of toxic secondary metabolites, among them the aflatoxins (AFs) are the most well-known. These compounds are highly mutagenic and carcinogenic, particularly AFB1. A. flavus is capable of colonizing economically important crops contaminating them with AFs. Molecu...

  16. Evaluation of resistance to aflatoxin contamination in kernels of maize genotypes using a GFP-expressing Aspergillus flavus strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation of resistance or susceptibility of corn inbreds to infection by Aspergillus flavus was evaluated by a kernel screening assay. A GFP-expressing strain of A. flavus was used to accomplish this study to measure fungal spread and aflatoxin levels in real time. Among the four inbreds tested, ...

  17. Field Assessment of Non-toxigenic Aspergillus flavus Strain K49 in Competitive Displacement of Toxigenic Isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-toxigenic strains of Aspergillus flavus offer the potential to control aflatoxin contamination by competitive displacement of indigenous populations of A. flavus colonizing corn grain. Two sets of experiments were conducted to assess the competitiveness of strain K49 when challenged against two...

  18. Genome sequence of Aspergillus flavus NRRL 3357, a strain that causes aflatoxin contamination of food and feed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination of food and livestock feed results in significant annual crop losses internationally. Aspergillus flavus is the major fungus responsible for this loss. Additionally, A. flavus is the second leading cause of aspergillosis in immune compromised human patients. Here we report th...

  19. Identification of Aspergillus flavus isolates as potential biocontrol agents of aflatoxin contamination in crops.

    PubMed

    Rosada, L J; Sant'anna, J R; Franco, C C S; Esquissato, G N M; Santos, P A S R; Yajima, J P R S; Ferreira, F D; Machinski, M; Corrêa, B; Castro-Prado, M A A

    2013-06-01

    Aspergillus flavus, a haploid organism found worldwide in a variety of crops, including maize, cottonseed, almond, pistachio, and peanut, causes substantial and recurrent worldwide economic liabilities. This filamentous fungus produces aflatoxins (AFLs) B1 and B2, which are among the most carcinogenic compounds from nature, acutely hepatotoxic and immunosuppressive. Recent efforts to reduce AFL contamination in crops have focused on the use of nonaflatoxigenic A. flavus strains as biological control agents. Such agents are applied to soil to competitively exclude native AFL strains from crops and thereby reduce AFL contamination. Because the possibility of genetic recombination in A. flavus could influence the stability of biocontrol strains with the production of novel AFL phenotypes, this article assesses the diversity of vegetative compatibility reactions in isolates of A. flavus to identify heterokaryon self-incompatible (HSI) strains among nonaflatoxigenic isolates, which would be used as biological controls of AFL contamination in crops. Nitrate nonutilizing (nit) mutants were recovered from 25 A. flavus isolates, and based on vegetative complementation between nit mutants and on the microscopic examination of the number of hyphal fusions, five nonaflatoxigenic (6, 7, 9 to 11) and two nontoxigenic (8 and 12) isolates of A. flavus were phenotypically characterized as HSI. Because the number of hyphal fusions is reduced in HSI strains, impairing both heterokaryon formation and the genetic exchanges with aflatoxigenic strains, the HSI isolates characterized here, especially isolates 8 and 12, are potential agents for reducing AFL contamination in crops. PMID:23726204

  20. Extracellular Xylanolytic and Pectinolytic Hydrolase Production by Aspergillus flavus Isolates Contributes to Crop Invasion

    PubMed Central

    Mellon, Jay E.

    2015-01-01

    Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium utilizing larch xylan as a sole carbon substrate. Four of the tested isolates produced reasonably high levels of esterase activity, while the atoxigenic biocontrol agent NRRL 21882 isolate esterase level was significantly lower than the others. Atoxigenic A. flavus isolates 19, 22, K49, AF36 (the latter two are biocontrol agents) and toxigenic AF13 produced copious levels of pectinolytic activity when grown on a pectin medium. The pectinolytic activity levels of the atoxigenic A. flavus 17 and NRRL 21882 isolates were significantly lower than the other tested isolates. In addition, A. flavus isolates that displayed high levels of pectinolytic activity in the plate assay produced high levels of endopolygalacturonase (pectinase) P2c, as ascertained by isoelectric focusing electrophoresis. Isolate NRRL 21882 displayed low levels of both pectinase P2c and pectin methyl esterase. A. flavus appears capable of producing these hydrolytic enzymes irrespective of aflatoxin production. This ability of atoxigenic isolates to produce xylanolytic and pectinolytic hydrolases mimics that of toxigenic isolates and, therefore, contributes to the ability of atoxigenic isolates to occupy the same niche as A. flavus toxigenic isolates. PMID:26295409

  1. Extracellular Xylanolytic and Pectinolytic Hydrolase Production by Aspergillus flavus Isolates Contributes to Crop Invasion.

    PubMed

    Mellon, Jay E

    2015-08-01

    Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium utilizing larch xylan as a sole carbon substrate. Four of the tested isolates produced reasonably high levels of esterase activity, while the atoxigenic biocontrol agent NRRL 21882 isolate esterase level was significantly lower than the others. Atoxigenic A. flavus isolates 19, 22, K49, AF36 (the latter two are biocontrol agents) and toxigenic AF13 produced copious levels of pectinolytic activity when grown on a pectin medium. The pectinolytic activity levels of the atoxigenic A. flavus 17 and NRRL 21882 isolates were significantly lower than the other tested isolates. In addition, A. flavus isolates that displayed high levels of pectinolytic activity in the plate assay produced high levels of endopolygalacturonase (pectinase) P2c, as ascertained by isoelectric focusing electrophoresis. Isolate NRRL 21882 displayed low levels of both pectinase P2c and pectin methyl esterase. A. flavus appears capable of producing these hydrolytic enzymes irrespective of aflatoxin production. This ability of atoxigenic isolates to produce xylanolytic and pectinolytic hydrolases mimics that of toxigenic isolates and, therefore, contributes to the ability of atoxigenic isolates to occupy the same niche as A. flavus toxigenic isolates. PMID:26295409

  2. Characterization of Humanized Antibodies Secreted by Aspergillus niger

    PubMed Central

    Ward, Michael; Lin, Cherry; Victoria, Doreen C.; Fox, Bryan P.; Fox, Judith A.; Wong, David L.; Meerman, Hendrik J.; Pucci, Jeff P.; Fong, Robin B.; Heng, Meng H.; Tsurushita, Naoya; Gieswein, Christine; Park, Minha; Wang, Huaming

    2004-01-01

    Two different humanized immunoglobulin G1(κ) antibodies and an Fab′ fragment were produced by Aspergillus niger. The antibodies were secreted into the culture supernatant. Both light and heavy chains were initially synthesized as fusion proteins with native glucoamylase. After antibody assembly, cleavage by A. niger KexB protease allowed the release of free antibody. Purification by hydrophobic charge induction chromatography proved effective at removing any antibody to which glucoamylase remained attached. Glycosylation at N297 in the Fc region of the heavy chain was observed, but this site was unoccupied on approximately 50% of the heavy chains. The glycan was of the high-mannose type, with some galactose present, and the size ranged from Hex6GlcNAc2 to Hex15GlcNAc2. An aglycosyl mutant form of antibody was also produced. No significant difference between the glycosylated antibody produced by Aspergillus and that produced by mammalian cell cultures was observed in tests for affinity, avidity, pharmacokinetics, or antibody-dependent cellular cytotoxicity function. PMID:15128505

  3. Putative Aspergillus niger-induced oxalate nephrosis in sheep.

    PubMed

    Botha, C J; Truter, M; Bredell, T; Lange, L; Mülders, M S G

    2009-03-01

    A sheep farmer provided a maize-based brewer's grain (mieliemaroek) and bales of Eragrostis curvula hay to ewes and their lambs, kept on zero-grazing in pens. The 'mieliemaroek' was visibly mouldy. After 14 days in the feedlot, clinical signs, including generalised weakness, ataxia of the hind limbs, tremors and recumbency, were noticed. Six ewes died within a period of 7 days. A post mortem examination was performed on 1 ewe. The carcass appeared to be cachectic with mild effusions into the body cavities; mild lung congestion and pallor of the kidneys were observed. Microscopical evaluation revealed nephrosis and birefringent oxalate crystals in the renal tubules when viewed under polarised light. A provisional diagnosis of oxalate nephrosis with subsequent kidney failure was made. Amongst other fungi, Aspergillus niger was isolated from 'mieliemaroek' samples submitted for fungal culture and identification. As A. niger is known to synthesise oxalates, a qualitative screen to detect oxalic acid in the mieliemaroek and purified A. niger isolates was performed using high-performance liquid chromatography (HPLC). Oxalic acid was detected, which supported a diagnosis of soluble oxalate-induced nephropathy. PMID:19653520

  4. Heterogeneity of Aspergillus niger Microcolonies in Liquid Shaken Cultures▿ †

    PubMed Central

    de Bekker, Charissa; van Veluw, G. Jerre; Vinck, Arman; Wiebenga, L. Ad; Wösten, Han A. B.

    2011-01-01

    The fungus Aspergillus niger forms (sub)millimeter microcolonies within a liquid shaken culture. Here, we show that such microcolonies are heterogeneous with respect to size and gene expression. Microcolonies of strains expressing green fluorescent protein (GFP) from the promoter of the glucoamlyase gene glaA or the ferulic acid esterase gene faeA were sorted on the basis of diameter and fluorescence using the Complex Object Parametric Analyzer and Sorter (COPAS) technology. Statistical analysis revealed that the liquid shaken culture consisted of two populations of microcolonies that differ by 90 μm in diameter. The population of small microcolonies of strains expressing GFP from the glaA or faeA promoter comprised 39% and 25% of the culture, respectively. Two populations of microcolonies could also be distinguished when the expression of GFP in these strains was analyzed. The population expressing a low level of GFP consisted of 68% and 44% of the culture, respectively. We also show that mRNA accumulation is heterogeneous within microcolonies of A. niger. Central and peripheral parts of the mycelium were isolated with laser microdissection and pressure catapulting (LMPC), and RNA from these samples was used for quantitative PCR analysis. This analysis showed that the RNA content per hypha was about 45 times higher at the periphery than in the center of the microcolony. Our data imply that the protein production of A. niger can be improved in industrial fermentations by reducing the heterogeneity within the culture. PMID:21169437

  5. Detection of Aspergillus flavus in stored peanuts using real-time PCR and the expression of aflatoxin genes in toxigenic and atoxigenic A. flavus isolates.

    PubMed

    Mahmoud, Mohamed A

    2015-04-01

    Aspergillus flavus is the main species from section Flavi responsible for aflatoxin accumulation in stored peanuts. Rapid methods to detect A. flavus could help to prevent aflatoxins from entering the food chain. A real-time polymerase chain reaction (RTi-PCR) assay was standardized for rapid, specific, and sensitive detection of A. flavus in stored peanuts. A. flavus was detected in 53.6% and 50% of peanut samples by RTi-PCR and A. flavus and Aspergillus parasiticus agar culture, respectively, with 95% agreement between them. Twenty-two A. flavus isolates were screened using high-performance liquid chromatography for their capacity to produce aflatoxin AFB1 (B1). B1 was produced by >72% of the isolates. Sixteen isolates produced B1 at concentrations ranging from 1.64 to 109.18 μg/mL. Four aflatoxin biosynthetic pathway genes (aflD, aflM, aflP, and aflQ) were evaluated using PCR and reverse-transcription PCR in 22 A. flavus isolates from peanut kernels with the aim of rapidly and accurately differentiating toxigenic and atoxigenic isolates. The PCR amplification of genes did not correlate with aflatoxin production capability. The expression of aflD and aflQ was a good marker for differentiating toxigenic from atoxigenic isolates. PMID:25621617

  6. Antifungal activity of extracts of Rosmarinus officinalis and Thymus vulgaris against Aspergillus flavus and A. ochraceus.

    PubMed

    Centeno, S; Calvo, M A; Adelantado, C; Figueroa, S

    2010-05-01

    The antifungal activity of ethanolic extracts of Rosmarinus officinalis and Thymus vulgaris were tested against strains of Aspergillus flavus and A. ochraceus, since these two species are common contaminants of cereals and grains and are able to produce and accumulate mycotoxins. The methodology used is based on measuring the inhibition halos produced by discs impregnated with the extracts and establishing their Minimum Inhibitory Concentration (MIC) as well as the Minimum Fungicide Concentration (MFC). The results obtained suggest that the assayed extracts affect the proper development of A. flavus and A. ochraceus; leading to a lower MIC (1200 ppm) and MFC (2400 ppm) for T. vulgaris extract against A. ochraceus than against A. flavus. The results show, that the extracts of Rosmarinus officinalis and Thymus vulgaris used at low concentrations could have significant potential for the biological control of fungi in foodstuffs. PMID:20973400

  7. Morphology engineering of Aspergillus niger for improved enzyme production.

    PubMed

    Driouch, Habib; Sommer, Becky; Wittmann, Christoph

    2010-04-15

    Supplementation with silicate microparticles was used as novel approach to control the morphological development of Aspergillus niger, important as the major world source of citric acid and higher-value enzymes, in submerged culture. With careful variation of size and concentration of the micromaterial added, a number of distinct morphological forms including pellets of different size, free dispersed mycelium, and short hyphae fragments could be reproducibly created. Aluminum oxide particles similarly affected morphology, showing that this effect is largely independent of the chemical particle composition. Image analysis of morphological development of A. niger during the cultivation process showed that the microparticles influence the morphology by collision-induced disruption of conidia aggregates and probably also the hindrance of new spore-spore interactions in the very early stage of the process. Exemplified for different recombinant A. niger strains enzyme production could be strongly enhanced by the addition of microparticles. Linked to the formation of freely dispersed mycelium, titers for glucoamylase (GA) expressed as intracellular enzyme (88 U/mL) and fructofuranosidase secreted into the supernatant (77 U/mL), were up to fourfold higher in shake flasks. Moreover, accumulation of the undesired by-product oxalate was suppressed by up to 90%. The microparticle strategy could be successfully transferred to fructofuranosidase production in bioreactor, where a final titer of 160 U/mL could be reached. Using co-expression of GA with green fluorescent protein, enzyme production was localized in the cellular aggregates of A. niger. For pelleted growth, protein production was maximal only within a thin layer at the pellet surface and markedly decreased in the pellet interior, whereas the interaction with the microparticles created a highly active biocatalyst with the dominant fraction of cells contributing to production. PMID:19953678

  8. Expression of human α1-proteinase inhibitor in Aspergillus niger

    PubMed Central

    Karnaukhova, Elena; Ophir, Yakir; Trinh, Loc; Dalal, Nimish; Punt, Peter J; Golding, Basil; Shiloach, Joseph

    2007-01-01

    Background Human α1-proteinase inhibitor (α1-PI), also known as antitrypsin, is the most abundant serine protease inhibitor (serpin) in plasma. Its deficiency is associated with development of progressive, ultimately fatal emphysema. Currently in the United States, α1-PI is available for replacement therapy as an FDA licensed plasma-derived (pd) product. However, the plasma source itself is limited; moreover, even with efficient viral inactivation steps used in manufacture of plasma products, the risk of contamination from emerging viruses may still exist. Therefore, recombinant α1-PI (r-α1-PI) could provide an attractive alternative. Although r-α1-PI has been produced in several hosts, protein stability in vitro and rapid clearance from the circulation have been major issues, primarily due to absent or altered glycosylation. Results We have explored the possibility of expressing the gene for human α1-PI in the filamentous fungus Aspergillus niger (A. niger), a system reported to be capable of providing more "mammalian-like" glycosylation patterns to secretable proteins than commonly used yeast hosts. Our expression strategy was based on fusion of α1-PI with a strongly expressed, secreted leader protein (glucoamylase G2), separated by dibasic processing site (N-V-I-S-K-R) that provides in vivo cleavage. SDS-PAGE, Western blot, ELISA, and α1-PI activity assays enabled us to select the transformant(s) secreting a biologically active glycosylated r-α1-PI with yields of up to 12 mg/L. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis further confirmed that molecular mass of the r-α1-PI was similar to that of the pd-α1-PI. In vitro stability of the r-α1-PI from A. niger was tested in comparison with pd-α1-PI reference and non-glycosylated human r-α1-PI from E. coli. Conclusion We examined the suitability of the filamentous fungus A. niger for the expression of the human gene for α1-PI, a medium size glycoprotein of high

  9. Molecular characterization of aflatoxigenic and non-aflatoxigenic Aspergillus flavus isolates collected from corn grains.

    PubMed

    Mahmoud, M A; Ali, H M; El-Aziz, A R M; Al-Othman, M R; Al-Wadai, A S

    2014-01-01

    Twelve species from six fungal genera were found to be associated with corn (Zea mays L.) grain samples collected from three main regions of Saudi Arabia. The average frequencies of the most common genera were Aspergillus (11.4%), Fusarium (9.5%), Penicillium (5.1%), and Alternaria (5.8%). Fifteen isolates of Aspergillus flavus were screened by HPLC for their ability to produce aflatoxins (AF). The percentage of aflatoxigenic A. flavus isolates was 53%. Eight isolates produced AF, at concentrations ranging 0.7-2.9 ppb. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) molecular markers were used to genetically characterize isolates of A. flavus and to discriminate between the aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, which was useful for genetic characterization. The clustering in the RAPD and ISSR dendrograms obtained was unrelated to geographic origin. The RAPD and ISSR markers could not discriminate between aflatoxigenic and non-aflatoxigenic isolates, but the ISSR primers were somewhat better. PMID:25501147

  10. [Aflatoxins produced by Aspergillus flavus in soya and other legumes].

    PubMed

    Topsy, K

    1977-01-01

    There is no doubt that our programme of applied nutrition must include soya on account of the high nutritive value of the legume. This underlines research undertaken here regarding the risks of contamination by A. flavus and the subsequent formation of aflatoxins on and in soya beans. We have studied on parallel lines soya beans and other legumes important in the local dietary habits. These legumes are either obtained locally or imported. On every specimen of legume we have tried to confirm, or otherwise, the presence of A. flavus and the aflatoxins. This was followed by experimenting on the conditions for growth and formation of aflatoxins on every one of the legumes. During subsequent experiments we have studied mixtures of legumes containing soya. Research on these lines has shown the inhibitory effects of legumes such as lentils, dried garden peas, Bengal gram, green peas, red peas, and broad beans on the growth of A. flavus and the formation of aflatoxins. Groundnut, on the other hand, seems to encourage such growth and such formation. The results of the experiments carried out, as above, lead us to conclude that soya must form part of our national food monitoring programme. PMID:418721

  11. ADOPTING SELECTED HYDROGEN BONDING AND IONIC INTERACTIONS FROM ASPERGILLUS FUMIGATUS PHYTASE STRUCTURE IMPROVES THE THERMOSTABILITY OF ASPERGILLUS NIGER PHYA PHYTASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although it has been widely used as a feed supplement to reduce manure phosphorus pollution of swine and poultry, Aspergillus niger PhyA phytase is unable to withstand heat inactivation during feed pelleting. Crystal structure comparisons with its close homolog, the thermostable Aspergillus fumigatu...

  12. The Mechanism of Antifungal Action of Essential Oil from Dill (Anethum graveolens L.) on Aspergillus flavus

    PubMed Central

    Tian, Jun; Ban, Xiaoquan; Zeng, Hong; He, Jingsheng; Chen, Yuxin; Wang, Youwei

    2012-01-01

    The essential oil extracted from the seeds of dill (Anethum graveolens L.) was demonstrated in this study as a potential source of an eco-friendly antifungal agent. To elucidate the mechanism of the antifungal action further, the effect of the essential oil on the plasma membrane and mitochondria of Aspergillus flavus was investigated. The lesion in the plasma membrane was detected through flow cytometry and further verified through the inhibition of ergosterol synthesis. The essential oil caused morphological changes in the cells of A. flavus and a reduction in the ergosterol quantity. Moreover, mitochondrial membrane potential (MMP), acidification of external medium, and mitochondrial ATPase and dehydrogenase activities were detected. The reactive oxygen species (ROS) accumulation was also examined through fluorometric assay. Exposure to dill oil resulted in an elevation of MMP, and in the suppression of the glucose-induced decrease in external pH at 4 µl/ml. Decreased ATPase and dehydrogenase activities in A. flavus cells were also observed in a dose-dependent manner. The above dysfunctions of the mitochondria caused ROS accumulation in A. flavus. A reduction in cell viability was prevented through the addition of L-cysteine, which indicates that ROS is an important mediator of the antifungal action of dill oil. In summary, the antifungal activity of dill oil results from its ability to disrupt the permeability barrier of the plasma membrane and from the mitochondrial dysfunction-induced ROS accumulation in A. flavus. PMID:22272289

  13. Degeneration of aflatoxin gene clusters in Aspergillus flavus from Africa and North America.

    PubMed

    Adhikari, Bishwo N; Bandyopadhyay, Ranajit; Cotty, Peter J

    2016-12-01

    Aspergillus flavus is the most common causal agent of aflatoxin contamination of food and feed. However, aflatoxin-producing potential varies widely among A. flavus genotypes with many producing no aflatoxins. Some non-aflatoxigenic genotypes are used as biocontrol agents to prevent contamination. Aflatoxin biosynthesis genes are tightly clustered in a highly conserved order. Gene deletions and presence of single nucleotide polymorphisms (SNPs) in aflatoxin biosynthesis genes are often associated with A. flavus inability to produce aflatoxins. In order to identify mechanisms of non-aflatoxigenicity in non-aflatoxigenic genotypes of value in aflatoxin biocontrol, complete cluster sequences of 35 A. flavus genotypes from Africa and North America were analyzed. Inability of some genotypes to produce aflatoxin resulted from deletion of biosynthesis genes. In other genotypes, non-aflatoxigenicity originated from SNP formation. The process of degeneration differed across the gene cluster; genes involved in early biosynthesis stages were more likely to be deleted while genes involved in later stages displayed high frequencies of SNPs. Comparative analyses of aflatoxin gene clusters provides insight into the diversity of mechanisms of non-aflatoxigenicity in A. flavus genotypes used as biological control agents. The sequences provide resources for both diagnosis of non-aflatoxigenicity and monitoring of biocontrol genotypes during biopesticide manufacture and in the environment. PMID:27576895

  14. Investigations on the Antifungal Effect of Nerol against Aspergillus flavus Causing Food Spoilage

    PubMed Central

    Tian, Jun; Zeng, Xiaobin; Zeng, Hong; Feng, Zhaozhong; Miao, Xiangmin; Peng, Xue

    2013-01-01

    The antifungal efficacy of nerol (NEL) has been proved against Aspergillus flavus by using in vitro and in vivo tests. The mycelial growth of A. flavus was completely inhibited at concentrations of 0.8 μL/mL and 0.1 μL/mL NEL in the air at contact and vapor conditions, respectively. The NEL also had an evident inhibitory effect on spore germination in A. flavus along with NEL concentration as well as time-dependent kinetic inhibition. The NEL presented noticeable inhibition on dry mycelium weight and synthesis of aflatoxin B1 (AFB1) by A. flavus, totally restraining AFB1 production at 0.6 μL/mL. In real food system, the efficacy of the NEL on resistance to decay development in cherry tomatoes was investigated in vivo by exposing inoculated and control fruit groups to NEL vapor at different concentration. NEL vapors at 0.1 μL/mL air concentration significantly reduced artificially contaminated A. flavus and a broad spectrum of fungal microbiota. Results obtained from presented study showed that the NEL had a great antifungal activity and could be considered as a benefit and safe tool to control food spoilage. PMID:24453813

  15. Loss of msnA, a putative stress regulatory gene, in Aspergillus parasiticus and Aspergillus flavus increased production of conidia, aflatoxins and kojic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of the harmful carcinogenic aflatoxins by Aspergillus parasiticus and Aspergillus flavus has been postulated to be a mechanism to relieve oxidative stress. The msnA gene, the ortholog of Saccharomyces cerevisiae MSN2 associated with multi-stress response, of the two species was disrupted....

  16. Aspergillus flavus biomass in maize estimated by quantitative real-time polymerase chain reaction is strongly correlated with aflatoxin concentration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus causes Aspergillus ear rot of maize and produces aflatoxins. There are published assertions that resistance to aflatoxin accumulation and pathogen colonization are distinct traits in maize. However, the levels of colonization are difficult to characterize for a pathogen such as ...

  17. Genome Sequences of Eight Aspergillus flavus spp. and One A. parasiticus sp., Isolated from Peanut Seeds in Georgia

    PubMed Central

    Wang, Xinye Monica; Palencia, Edwin R.

    2016-01-01

    Aspergillus flavus and A. parasiticus fungi produce carcinogenic mycotoxins in peanut seeds, causing considerable impact on both human health and the economy. Here, we report nine genome sequences of Aspergillus spp., isolated from Georgia peanut seeds in 2014. The information obtained will lead to further biodiversity studies that are essential for developing control strategies. PMID:27081142

  18. Genome Sequences of Eight Aspergillus flavus spp. and One A. parasiticus sp., Isolated From Peanut Seeds in Georgia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and A. parasiticus fungi, carcinogen-mycotoxins producers, infect peanut seeds, causing considerable impact on both human health and the economy. Here we report 9 genome sequences of Aspergillus spp. isolated from peanut seeds. The information obtained will allow conducting biodiv...

  19. Clustered Genes Involved in Cyclopiazonic Acid Production are Next to the Aflatoxin Biosynthesis Gene Cluster in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclopiazonic acid (CPA), an indole-tetramic acid toxin, is produced by many species of Aspergillus and Penicillium. In addition to CPA Aspergillus flavus produces polyketide-derived carcinogenic aflatoxins (AFs). AF biosynthesis genes form a gene cluster in a subtelomeric region. Isolates of A. fla...

  20. Distribution and conformation of crystalline nigeran in hyphal walls of Aspergillus niger and Aspergillus awamori.

    PubMed Central

    Bobbitt, T F; Nordin, J H; Roux, M; Revol, J F; Marchessault, R H

    1977-01-01

    Hyphal walls of Aspergillus awamori containing increased amount of the alpha-glucan, nigeran, became correspondingly more opaque when viewed in the electron microscope as shadowed preparations. However, increased polymer deposition was not accompanied by any significant change in wall thickness. The nigeran of both A. awamori and Aspergillus niger occurred in situ in a crystalline conformation identical to that of single crystals prepared with pure polysaccharide. Furthermore, this polymer was the dominant crystalline material in the hyphae whether or not they were enriched in nigeran. Enzymic digestion of nigeran in A. niger and A. awamori revealed that the bulk of the polymer was exposed to the cell's exterior. However, a certain fraction was accessible to enzymic attack only after the wall was treated with boiling water. A third portion, detectable only by x-ray diffraction, was associated with other components and could not be extracted, even with prolonged boiling. It was removed by hot, dilute alkali and was associated in the wall with another glucan fraction. Dry heating of A. niger walls altered their susceptibility to enzymic digestion of nigeran in situ. It is proposed that this treatment introduces interstices in the crystal surface that facilitate attack. Images PMID:914782

  1. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Choudhury, Samrat Roy; Nair, Kishore K.; Kumar, Rajesh; Gogoi, Robin; Srivastava, Chitra; Gopal, Madhuban; Subhramanyam, B. S.; devakumar, C.; Goswami, Arunava

    2010-10-01

    Elemental sulfur (S0), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  2. Biotransformation of Steroids and Flavonoids by Cultures of Aspergillus niger.

    PubMed

    Parshikov, Igor A; Sutherland, John B

    2015-06-01

    Steroids are derivatives of the triterpenoid squalene, containing three fused cyclohexane rings and a cyclopentane ring, and flavonoids are derivatives of L-phenylalanine, containing two aromatic rings joined by a three-carbon bridge that may form part of a heterocyclic ring. A great variety of steroids and flavonoids are produced by plants, and many additional steroids are produced by animals or fungi. Because these compounds have many nutritional and pharmaceutical values, and many of them cannot be produced by chemical synthesis, biotechnological processes are being developed that use cultures of Aspergillus niger and other fungi to transform steroids and flavonoids to a variety of metabolites. These biochemical reactions, including hydroxylation, dehydrogenation, O-methylation, demethylation, cleavage of rings, epoxide hydrolysis, double bond reduction, and others, may be used for the production of higher-value compounds. PMID:25951777

  3. Biotransformation of germacranolide from Onopordon leptolepies by Aspergillus niger.

    PubMed

    Esmaeili, Akbar; Moazami, Nasrin; Rustaiyan, Abdolhossein

    2012-01-01

    Terpenes are present in the essential oils obtained from herbs and spices. They are produced by these plant species as a chemical defense mechanism against phytopathogenic microorganisms. Therefore, terpenes have attracted great attention in the food industry, e.g., they have been used in foods such as cheese as natural preservatives to prevent fungal growth. Herein, we describe the microbial transformation of onopordopicrin (1) by Aspergillus niger. Four product 11α H-dihydroonopordopicrin (2), 11β H-dihydroonopordopicrin (3), 3β-hydroxy-11β H-dihydroonopordopicrin (4), and 14-hydroxy-11β H-dihydroonopordopicrin (5) were obtained. Their structures were identified on the basis of chemical and spectroscopic data. All the four compounds were novel. PMID:22186324

  4. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    SciTech Connect

    Choudhury, Samrat Roy; Goswami, Arunava; Nair, Kishore K.; Kumar, Rajesh; Gopal, Madhuban; Devakumar, C.; Gogoi, Robin; Srivastava, Chitra; Subhramanyam, B. S.

    2010-10-04

    Elemental sulfur (S{sup 0}), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  5. Biotransformation of 6-dehydroprogesterone with Aspergillus niger and Gibberella fujikuroi.

    PubMed

    Ahmad, Malik Shoaib; Zafar, Salman; Yousuf, Sammar; Wahab, Atia-Tul-; Rahman, Atta-Ur-; Choudhary, M Iqbal

    2016-08-01

    Microbial transformation of 6-dehydroprogesterone (1) with Aspergillus niger yielded three new metabolites, including 6β-chloro-7α,11α-dihydroxypregna-4-ene-3,20-dione (2), 7α-chloro-6β,11α-dihydroxypregna-4-ene-3,20-dione (3), and 6α,7α-epoxy-11α-hydroxypregna-4-ene-3,20-dione (4), and two known metabolites; 6α,7α-epoxypregna-4-ene-3,20-dione (5), and 11α-hydroxypregna-4,6-diene-3,20-dione (6). Compounds 2, and 3 contain chlorohydrin moiety at C-6, and C-7, respectively. The biotransformation of 1 with Gibberella fujikuroi yielded a known compound, 11α,17β-dihydroxyandrosta-4,6-dien-3-one (7). PMID:27133903

  6. In-silico analysis of Aspergillus niger beta-glucosidases

    NASA Astrophysics Data System (ADS)

    Yeo S., L.; Shazilah, K.; Suhaila, S.; Abu Bakar F., D.; Murad A. M., A.

    2014-09-01

    Genomic data mining was carried out and revealed a total of seventeen β-glucosidases in filamentous fungi Aspergillus niger. Two of them belonged to glycoside hydrolase family 1 (GH1) while the rest belonged to genes in family 3 (GH3). These proteins were then named according to the nomenclature as proposed by the International Union of Biochemistry (IUB), starting from the lowest pI and glycoside hydrolase family. Their properties were predicted using various bionformatic tools showing the presence of domains for signal peptide and active sites. Interestingly, one particular domain, PA14 (protective antigen) was present in four of the enzymes, predicted to be involved in carbohydrate binding. A phylogenetic tree grouped the two glycoside hydrolase families with GH1 and GH3 related organisms. This study showed that the various domains present in these β-glucosidases are postulated to be crucial for the survival of this fungus, as supported by other analysis.

  7. Tandem shock waves to enhance genetic transformation of Aspergillus niger.

    PubMed

    Loske, Achim M; Fernández, Francisco; Magaña-Ortíz, Denis; Coconi-Linares, Nancy; Ortíz-Vázquez, Elizabeth; Gómez-Lim, Miguel A

    2014-08-01

    Filamentous fungi are used in several industries and in academia to produce antibiotics, metabolites, proteins and pharmaceutical compounds. The development of valuable strains usually requires the insertion of recombinant deoxyribonucleic acid; however, the protocols to transfer DNA to fungal cells are highly inefficient. Recently, underwater shock waves were successfully used to genetically transform filamentous fungi. The purpose of this research was to demonstrate that the efficiency of transformation can be improved significantly by enhancing acoustic cavitation using tandem (dual-pulse) shock waves. Results revealed that tandem pressure pulses, generated at a delay of 300 μs, increased the transformation efficiency of Aspergillus niger up to 84% in comparison with conventional (single-pulse) shock waves. This methodology may also be useful to obtain new strains required in basic research and biotechnology. PMID:24680880

  8. New pathway for the biodegradation of indole in Aspergillus niger

    SciTech Connect

    Kamath, A.; Vaidyanathan, C.S. )

    1990-01-01

    Indole and its derivatives form a class of toxic recalcitrant environmental pollutants. The growth of Aspergillus niger was inhibited by very low concentrations (0.005 to 0.02%) of indole, even when 125- to 500-fold excess glucose was present in the medium. When 0.02% indole was added, the fungus showed a lag phase for about 30 h and the uptake of glucose was inhibited. Indole was metabolized by a new pathway via indoxyl (3-hydroxyindole), N-formylanthranilic acid, anthranilic acid, 2,3-dihydroxybenzoic acid, and catechol, which was further degraded by an ortho cleavage. The enzymes N-formylanthranilate deformylase, anthranilate hydroxylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were induced by indole as early as after 5 h of growth, and their activities were demonstrated in a cell-free system.

  9. Preparation of 3-deacetyl cephalosporins by Aspergillus niger lipase.

    PubMed

    Carrea, G; Corcelli, A; Palmisano, G; Riva, S

    1996-12-20

    Lipase from Aspergillus niger was used for the selective hydrolysis of the 3-O-acetate of cephalosporin C to give an intermediate useful for further chemical elaborations. This lipase was purified to homogeneity and its properties compared with previously published data that present some discrepancies. The lipase proved to be very effective in catalyzing 3-O-acetate hydrolysis and versatile toward substitution on the beta-lactamic ring. In fact, as an example, two other cephalosporinic derivatives, cephalotin and cefotaxime, were efficiently deacetylated. The lipase was immobilized on Eupergit C and employed continuously in either a column or a batch reactor for 2 months without appreciable loss of activity. (c) 1996 John Wiley & Sons, Inc. PMID:18629943

  10. [Aspergillus niger alpha-N-acetylgalactosaminidase: isolation, purification and properties].

    PubMed

    Borzova, N V; Varbanets, L D

    2006-01-01

    alpha-N-acetylgalactosaminidase has been isolated from liquid culture of micromycete Aspergillus niger and purified 600 times by ammonium sulphate precipitation followed by ion exchange and gel-filtration chromatography on TSK-gels with specific activity 10.5 U/mg of protein. The preparation was homogenic: its molecular mass by the data of gel-filtration on Sepharose 6B was 430 kDa, on PAAGE in the system of DDSNa--70 kDa. That gives every reason to suppose oligomeric structure of the enzyme molecule. The carbohydrate component, including mannose, galactose, glucosamine and two nonidentified hexosamines was observed in alpha-N-acetylgalactosaminidase. Thermo- and pH- optima were 60 degrees C and pH 3.5, respectively. The enzyme was thermo- and pH-stable, resistant in storage. The enzyme was found to exhibit strict specificity in respect ofglycon. It was shown that enzyme was competitively inhibited by substrate and reaction product. Km and Vmax with respect to nitrophenyl substrate were 1.25 mM and 10.5 mkmole/min/mg of protein. The activity of glycosidase tested was independent of the presence of metal ions. The presence of carboxylic group of C-terminal aminoacid and imidazol group of hystidine in active centre of molecule was established. A number of natural and synthetic substrates were able to activate (50-200%) production of A. niger alpha-N-acetylgalactosaminidase. PMID:17290780

  11. Mapping the polysaccharide degradation potential of Aspergillus niger

    PubMed Central

    2012-01-01

    Background The degradation of plant materials by enzymes is an industry of increasing importance. For sustainable production of second generation biofuels and other products of industrial biotechnology, efficient degradation of non-edible plant polysaccharides such as hemicellulose is required. For each type of hemicellulose, a complex mixture of enzymes is required for complete conversion to fermentable monosaccharides. In plant-biomass degrading fungi, these enzymes are regulated and released by complex regulatory structures. In this study, we present a methodology for evaluating the potential of a given fungus for polysaccharide degradation. Results Through the compilation of information from 203 articles, we have systematized knowledge on the structure and degradation of 16 major types of plant polysaccharides to form a graphical overview. As a case example, we have combined this with a list of 188 genes coding for carbohydrate-active enzymes from Aspergillus niger, thus forming an analysis framework, which can be queried. Combination of this information network with gene expression analysis on mono- and polysaccharide substrates has allowed elucidation of concerted gene expression from this organism. One such example is the identification of a full set of extracellular polysaccharide-acting genes for the degradation of oat spelt xylan. Conclusions The mapping of plant polysaccharide structures along with the corresponding enzymatic activities is a powerful framework for expression analysis of carbohydrate-active enzymes. Applying this network-based approach, we provide the first genome-scale characterization of all genes coding for carbohydrate-active enzymes identified in A. niger. PMID:22799883

  12. Cryptic Sexuality Influences Aflatoxigenicity in Aspergillus parasiticus and A. flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascomycetous fungi of the genus Aspergillus comprise a wide variety of species of biotechnological importance as well as pathogens and toxin producers. Recent studies report A. fumigatus to be heterothallic and possibly undergoing sexual reproduction. We therefore investigated whether compatible mat...

  13. Induced Autolysis of Aspergillus oryzae (A. niger group)

    PubMed Central

    Emiliani, Ezio; de Davie, I. Ucha

    1962-01-01

    The examination of substances formed during induced autolysis by Aspergillus niger was continued in this work, which dealt in particular with carbohydrates. The autolysate contained a large amount of d-glucose (14 to 20% dry wt) and traces of glycolic aldehyde, dihydroxyacetone, ribose, xylose, and fructose. It also contained glycopeptides (about 10% dry wt), which were split from the cell wall during autolysis and which differed from one another in their level of polymerization and their composition. They were constituted by glucose and mannose, glucose and galactose, or mannose, glucose, and galactose (mannose being the most abundant in this case), and amino acids (chiefly alanine, serine, glutamic acid, and aspartic acid). During autolysis, only a part of the cell wall was dissolved, since it retained its shape. Upon further chemical hydrolysis, it produced mostly glucose and glucosamine, and smaller amounts of mannose, galactose, and amino acids. Presumably, glucomannoproteins and glucogalactoproteins were present in the intact cell as a macromolecular complex, constituting, together with chitin, the major part of the cell wall of Aspergillus. PMID:16349623

  14. Molecular characterisation of Aspergillus flavus isolates from peanut fields in India using AFLP

    PubMed Central

    Singh, Diwakar; Radhakrishnan, T.; Kumar, Vinod; Bagwan, N.B.; Basu, M.S.; Dobaria, J.R.; Mishra, Gyan P.; Chanda, S.V.

    2015-01-01

    Aflatoxin contamination of peanut, due to infection by Aspergillus flavus, is a major problem of rain-fed agriculture in India. In the present study, molecular characterisation of 187 Aspergillus flavus isolates, which were sampled from the peanut fields of Gujarat state in India, was performed using AFLP markers. On a pooled cluster analysis, the markers could successfully discriminate among the ‘A’, ‘B’ and ‘G’ group A. flavus isolates. PCoA analysis also showed equivalent results to the cluster analysis. Most of the isolates from one district could be clustered together, which indicated genetic similarity among the isolates. Further, a lot of genetic variability was observed within a district and within a group. The results of AMOVA test revealed that the variance within a population (84%) was more than that between two populations (16%). The isolates, when tested by indirect competitive ELISA, showed about 68.5% of them to be atoxigenic. Composite analysis between the aflatoxin production and AFLP data was found to be ineffective in separating the isolate types by aflatoxigenicity. Certain unique fragments, with respect to individual isolates, were also identified that may be used for development of SCAR marker to aid in rapid and precise identification of isolates. PMID:26413047

  15. Molecular characterization of Aspergillus flavus and aflatoxin contamination of wheat grains from Saudi Arabia.

    PubMed

    Al-Wadai, A S; Al-Othman, M R; Mahmoud, M A; Abd El-Aziz, A R M

    2013-01-01

    Twelve species belonging to six fungal genera were found to be associated with wheat (Triticum aestivum L.) grain samples collected from three main regions in Saudi Arabia. The most common genera (average frequency) were Aspergillus (14.3%), Fusarium (29.1%), Penicillium (9.3%), and Alternaria (8.2%). Nineteen isolates of Aspergillus flavus were screened for their ability to produce aflatoxins using HPLC. Thirteen isolates produced aflatoxins ranging from 0.5 to 2.6 µg/kg. Inter-simple sequence repeats (ISSR), and random amplified polymorphic DNA (RAPD) molecular markers were used, with the aim of genetically characterizing strains of A. flavus to discriminate between aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, useful for genetic characterization. Clustering based on RAPD and ISSR dendograms was unrelated to geographic origin. RAPD and ISSR markers were not suitable to discriminate aflatoxigenic and non-aflatoxigenic isolates, but ISSR primers were better compared to RAPD. PMID:24065675

  16. Seventeen years of subcutaneous infection by Aspergillus flavus; eumycetoma confirmed by immunohistochemistry.

    PubMed

    Ahmed, Sarah A; Abbas, Manal A; Jouvion, Gregory; Al-Hatmi, Abdullah M S; de Hoog, G Sybren; Kolecka, Anna; Mahgoub, El Sheikh

    2015-12-01

    Chronic subcutaneous infections caused by Aspergillus species are considered to be extremely rare. Because these fungi are among the most common laboratory contaminants, their role as eumycetoma causative agents is difficult to ascertain. Here, we report the first case of A. flavus eumycetoma confirmed by isolation, molecular identification and immunohistochemical analysis. Patient was a 55-year-old male from Sudan suffering from eumycetoma on his left foot for a period of 17 years. He developed swelling, sinuses and white grain discharge was observed. He has been operated nine times and was treated with several regimens of ketoconazole and itraconazole without improvement. Initial diagnosis based on histology and radiology was Scedosporium eumycetoma. However, examination of the biopsy revealed A. flavus, which was identified by molecular analysis and MALDI-TOF MS. Immunohistochemistry using antibody directed against Aspergillus species was positive. Because of the earlier treatment failures with ketoconazole and itraconazole, therapy with voriconazole was initiated. However, in vitro susceptibility testing yielded a lower Minimum Inhibitory Concentration (MIC) value for itraconazole (0.25 μg ml(-1) ) than for voriconazole (1 μg ml(-1) ). Based on the presented results, A. flavus can be considered as one of the agents of white-grain eumycetoma. PMID:26497138

  17. Role of 3-Nitropropanoic Acid in Nitrate Formation by Aspergillus flavus1

    PubMed Central

    Doxtader, K. G.; Alexander, M.

    1966-01-01

    Doxtader, K. G. (Cornell University, Ithaca, N.Y.), and M. Alexander. Role of 3-nitropropanoic acid in nitrate formation by Aspergillus flavus. J. Bacteriol. 91:1186–1191. 1966.—Aspergillus flavus formed nitrate, 3-nitropropanoic acid (3-NPA), kojic acid, and a substance tentatively identified as N-formyl-N-hydroxy-glycine during growth in a medium with ammonium as sole nitrogen source. The concentration of the nitro compound reached a maximum prior to the appearance of nitrate; the 3-NPA level subsequently decreased with a concomitant increase in nitrate concentration. Replacement cultures of A. flavus produced nitrate from culture filtrates containing 3-NPA or from synthetic 3-NPA but not when supplied with fresh ammonium-sucrose medium, the nitrate-nitrogen formed being equivalent to 50% of the quantity of the 3-NPA-nitrogen initially present. Neither nitrate nor 3-NPA was synthesized by the fungus during growth in media with low pH or low ammonium concentrations. It is proposed that 3-NPA is either an intermediate or is in equilibrium with an intermediate in nitrification by the fungus. PMID:5929750

  18. Effects of Nutrients in Substrates of Different Grains on Aflatoxin B1 Production by Aspergillus flavus.

    PubMed

    Liu, Jie; Sun, Lvhui; Zhang, Niya; Zhang, Jiacai; Guo, Jiao; Li, Chong; Rajput, Shahid Ali; Qi, Desheng

    2016-01-01

    The current study was to better understand the potential factors affecting aflatoxin B1 (AFB1) accumulation varies between different grains. The nutrient composition and contents of defatted substrates were determined; additionally, according to the nutrient content of the substrates, the effects of starch, soluble sugars, amino acids, and trace elements on AFB1 production and mycelial growth in Czapek-Dox medium were examined. These results verified that removal of lipids from ground substrates significantly reduced the substrate's potential for AFB1 production by Aspergillus flavus. Maltose, glucose, sucrose, arginine, glutamic acid, aspartic acid, and zinc significantly induced AFB1 production up to 1.7- to 26.6-fold. And stachyose more significantly promoted A. flavus growth than the other nutrients. Thus, this study demonstrated that, combined with the nutrients content of grains, in addition to lipids, sucrose, stachyose, glutamic acid, and zinc might play key roles in various grains that are differentially infected by A. flavus. Particularly, two new nutrients (arginine and stachyose) of the grains we found significantly stimulate AFB1 production and A. flavus growth, respectively. The results provide new concepts for antifungal methods to protect food and animal feed from AFB1 contamination. PMID:27294129

  19. Aflatoxins in Rice Artificially Contaminated with Aflatoxin-producing Aspergillus flavus under Natural Storage in Japan.

    PubMed

    Sugihara, Satoshi; Doi, Hiroyuki; Kato, Masahiko; Mitoh, Yoshihiro; Tsuda, Toshihide; Ikeda, Satoru

    2016-06-01

    Aflatoxin (AFT) contamination is frequent in foods grown in tropical regions, including rice. Although AFTs are generally not found in temperate-region foods, global warming has affected typical temperate-region climates, potentially permitting the contamination of foods with AFT-producing Aspergillus flavus (A. flavus). Here we investigated the AFT production in rice during storage under natural climate conditions in Japan. We examined AFTs in brown rice and rough rice artificially contaminated with A. flavus for 1 year in Japan, and we subjected AFTs in white rice to the same treatment in airtight containers and examined the samples in warm and cold seasons, simulating the storage of white rice in general households. In the brown rice, AFTs increased after 2 months (March) and peaked after 9 months (October). The AFT contamination in the rough rice was minimal. After the polishing and cooking of the brown rice, AFTs were undetectable. In the white rice stored in airtight containers, AFTs increased after 1 month (August) and peaked after 2 months (September). Minimal AFTs were detected in the cold season. Thus, AFT contamination in rice may occur in temperate regions following A. flavus contamination. The storage of rice as rough rice could provide be useful for avoiding AFT contamination. PMID:27339205

  20. Role of Oxidative Stress in Sclerotial Differentiation and Aflatoxin B1 Biosynthesis in Aspergillus flavus

    PubMed Central

    Grintzalis, Konstantinos; Vernardis, Spyros I.; Klapa, Maria I.

    2014-01-01

    We show here that oxidative stress is involved in both sclerotial differentiation (SD) and aflatoxin B1 biosynthesis in Aspergillus flavus. Specifically, we observed that (i) oxidative stress regulates SD, as implied by its inhibition by antioxidant modulators of reactive oxygen species and thiol redox state, and that (ii) aflatoxin B1 biosynthesis and SD are comodulated by oxidative stress. However, aflatoxin B1 biosynthesis is inhibited by lower stress levels compared to SD, as shown by comparison to undifferentiated A. flavus. These same oxidative stress levels also characterize a mutant A. flavus strain, lacking the global regulatory gene veA. This mutant is unable to produce sclerotia and aflatoxin B1. (iii) Further, we show that hydrogen peroxide is the main modulator of A. flavus SD, as shown by its inhibition by both an irreversible inhibitor of catalase activity and a mimetic of superoxide dismutase activity. On the other hand, aflatoxin B1 biosynthesis is controlled by a wider array of oxidative stress factors, such as lipid hydroperoxide, superoxide, and hydroxyl and thiyl radicals. PMID:25002424

  1. RNA-Seq-Based Transcriptome Analysis of Aflatoxigenic Aspergillus flavus in Response to Water Activity

    PubMed Central

    Zhang, Feng; Guo, Zhenni; Zhong, Hong; Wang, Sen; Yang, Weiqiang; Liu, Yongfeng; Wang, Shihua

    2014-01-01

    Aspergillus flavus is one of the most important producers of carcinogenic aflatoxins in crops, and the effect of water activity (aw) on growth and aflatoxin production of A. flavus has been previously studied. Here we found the strains under 0.93 aw exhibited decreased conidiation and aflatoxin biosynthesis compared to that under 0.99 aw. When RNA-Seq was used to delineate gene expression profile under different water activities, 23,320 non-redundant unigenes, with an average length of 1297 bp, were yielded. By database comparisons, 19,838 unigenes were matched well (e-value < 10−5) with known gene sequences, and another 6767 novel unigenes were obtained by comparison to the current genome annotation of A. flavus. Based on the RPKM equation, 5362 differentially expressed unigenes (with |log2Ratio| ≥ 1) were identified between 0.99 aw and 0.93 aw treatments, including 3156 up-regulated and 2206 down-regulated unigenes, suggesting that A. flavus underwent an extensive transcriptome response during water activity variation. Furthermore, we found that the expression of 16 aflatoxin producing-related genes decreased obviously when water activity decreased, and the expression of 11 development-related genes increased after 0.99 aw treatment. Our data corroborate a model where water activity affects aflatoxin biosynthesis through increasing the expression of aflatoxin producing-related genes and regulating development-related genes. PMID:25421810

  2. Effects of Nutrients in Substrates of Different Grains on Aflatoxin B1 Production by Aspergillus flavus

    PubMed Central

    Liu, Jie; Sun, Lvhui; Zhang, Niya; Zhang, Jiacai; Guo, Jiao; Li, Chong; Rajput, Shahid Ali; Qi, Desheng

    2016-01-01

    The current study was to better understand the potential factors affecting aflatoxin B1 (AFB1) accumulation varies between different grains. The nutrient composition and contents of defatted substrates were determined; additionally, according to the nutrient content of the substrates, the effects of starch, soluble sugars, amino acids, and trace elements on AFB1 production and mycelial growth in Czapek-Dox medium were examined. These results verified that removal of lipids from ground substrates significantly reduced the substrate's potential for AFB1 production by Aspergillus flavus. Maltose, glucose, sucrose, arginine, glutamic acid, aspartic acid, and zinc significantly induced AFB1 production up to 1.7- to 26.6-fold. And stachyose more significantly promoted A. flavus growth than the other nutrients. Thus, this study demonstrated that, combined with the nutrients content of grains, in addition to lipids, sucrose, stachyose, glutamic acid, and zinc might play key roles in various grains that are differentially infected by A. flavus. Particularly, two new nutrients (arginine and stachyose) of the grains we found significantly stimulate AFB1 production and A. flavus growth, respectively. The results provide new concepts for antifungal methods to protect food and animal feed from AFB1 contamination. PMID:27294129

  3. The Aspergillus flavus Histone Acetyltransferase AflGcnE Regulates Morphogenesis, Aflatoxin Biosynthesis, and Pathogenicity

    PubMed Central

    Lan, Huahui; Sun, Ruilin; Fan, Kun; Yang, Kunlong; Zhang, Feng; Nie, Xin Y.; Wang, Xiunai; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    Histone acetyltransferases (HATs) help regulate fungal development and the production of secondary metabolites. In this study, we determined that the HAT AflGcnE influenced morphogenesis and aflatoxin biosynthesis in Aspergillus flavus. We observed that AflGcnE localized to the nucleus and cytoplasm during the conidial production and germination stages, while it was located mainly in the nucleus during the hyphal development stage. Deletion of AflgcnE inhibited the growth of A. flavus and decreased the hydrophobicity of the cell surface. The ΔAflgcnE mutant exhibited a lack of asexual sporulation and was unable to generate sclerotia. Additionally, AflgcnE was required to maintain cell wall integrity and genotoxic stress responses. Importantly, the ΔAflgcnE mutant did not produce aflatoxins, which was consistent with a significant down-regulation of aflatoxin gene expression levels. Furthermore, our data revealed that AflgcnE is a pathogenicity factor required for colonizing maize seeds. In summary, we revealed that A. flavus AflGcnE is crucial for morphological development, aflatoxin biosynthesis, stress responses, and pathogenicity. Our findings help clarify the functional divergence of GcnE orthologs, and may provide a possible target for controlling A. flavus infections of agriculturally important crops. PMID:27625637

  4. The DmtA methyltransferase contributes to Aspergillus flavus conidiation, sclerotial production, aflatoxin biosynthesis and virulence.

    PubMed

    Yang, Kunlong; Liang, Linlin; Ran, Fanlei; Liu, Yinghang; Li, Zhenguo; Lan, Huahui; Gao, Peili; Zhuang, Zhenhong; Zhang, Feng; Nie, Xinyi; Kalayu Yirga, Shimuye; Wang, Shihua

    2016-01-01

    DNA methylation is essential for epigenetic regulation of gene transcription and development in many animals, plants and fungi. We investigated whether DNA methylation plays a role in the development and secondary metabolism of Aspergillus flavus, identified the DmtA methyltransferase from A. flavus, and produced a dmtA knock-out mutant by replacing the dmtA coding sequence with the pyrG selectable marker. The A. flavus dmtA null mutant lines produced white fluffy mycelium in liquid medium, and displayed a slightly flavescent conidial pigmentation compared with the normal yellow of the wild-type strain when grown on agar. The ΔdmtA lines exhibited decreased conidiation and aflatoxin (AF) biosynthesis, compared with the wild-type line, suggesting that the DmtA knock-out affected the transcriptional level of genes in the AF cluster. In particular, sclerotia development and host colonization were altered in the dmtA null mutants. Green fluorescent protein tagging at the C-terminus of DmtA showed that DmtA localized to the nucleus and cytoplasm. DNA methylation content measurements in the dmtA mutants revealed no widespread DNA methylation in the mutants or wild-type lines. Thus, our findings suggest that DmtA, apart from being a C-5 cytosine methyltransferase in A. flavus, contributes to asexual development, aflatoxin biosynthesis, sclerotial production and virulence. PMID:26979781

  5. Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination.

    PubMed

    Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

    2013-10-01

    The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log10 control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log10 reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. PMID:23831798

  6. The Aspergillus flavus Histone Acetyltransferase AflGcnE Regulates Morphogenesis, Aflatoxin Biosynthesis, and Pathogenicity.

    PubMed

    Lan, Huahui; Sun, Ruilin; Fan, Kun; Yang, Kunlong; Zhang, Feng; Nie, Xin Y; Wang, Xiunai; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    Histone acetyltransferases (HATs) help regulate fungal development and the production of secondary metabolites. In this study, we determined that the HAT AflGcnE influenced morphogenesis and aflatoxin biosynthesis in Aspergillus flavus. We observed that AflGcnE localized to the nucleus and cytoplasm during the conidial production and germination stages, while it was located mainly in the nucleus during the hyphal development stage. Deletion of AflgcnE inhibited the growth of A. flavus and decreased the hydrophobicity of the cell surface. The ΔAflgcnE mutant exhibited a lack of asexual sporulation and was unable to generate sclerotia. Additionally, AflgcnE was required to maintain cell wall integrity and genotoxic stress responses. Importantly, the ΔAflgcnE mutant did not produce aflatoxins, which was consistent with a significant down-regulation of aflatoxin gene expression levels. Furthermore, our data revealed that AflgcnE is a pathogenicity factor required for colonizing maize seeds. In summary, we revealed that A. flavus AflGcnE is crucial for morphological development, aflatoxin biosynthesis, stress responses, and pathogenicity. Our findings help clarify the functional divergence of GcnE orthologs, and may provide a possible target for controlling A. flavus infections of agriculturally important crops. PMID:27625637

  7. Comparative Chemistry of Aspergillus oryzae (RIB40) and A. flavus (NRRL 3357)

    PubMed Central

    Rank, Christian; Klejnstrup, Marie Louise; Petersen, Lene Maj; Kildgaard, Sara; Frisvad, Jens Christian; Gotfredsen, Charlotte Held; Larsen, Thomas Ostenfeld

    2012-01-01

    Aspergillus oryzae and A. flavus are important species in industrial biotechnology and food safety and have been some of the first aspergilli to be fully genome sequenced. Bioinformatic analysis has revealed 99.5% gene homology between the two species pointing towards a large coherence in the secondary metabolite production. In this study we report on the first comparison of secondary metabolite production between the full genome sequenced strains of A. oryzae (RIB40) and A. flavus (NRRL 3357). Surprisingly, the overall chemical profiles of the two strains were mostly very different across 15 growth conditions. Contrary to previous studies we found the aflatrem precursor 13-desoxypaxilline to be a major metabolite from A. oryzae under certain growth conditions. For the first time, we additionally report A. oryzae to produce parasiticolide A and two new analogues hereof, along with four new alkaloids related to the A. flavus metabolites ditryptophenalines and miyakamides. Generally the secondary metabolite capability of A. oryzae presents several novel end products likely to result from the domestication process from A. flavus. PMID:24957367

  8. The DmtA methyltransferase contributes to Aspergillus flavus conidiation, sclerotial production, aflatoxin biosynthesis and virulence

    PubMed Central

    Yang, Kunlong; Liang, Linlin; Ran, Fanlei; Liu, Yinghang; Li, Zhenguo; Lan, Huahui; Gao, Peili; Zhuang, Zhenhong; Zhang, Feng; Nie, Xinyi; Kalayu Yirga, Shimuye; Wang, Shihua

    2016-01-01

    DNA methylation is essential for epigenetic regulation of gene transcription and development in many animals, plants and fungi. We investigated whether DNA methylation plays a role in the development and secondary metabolism of Aspergillus flavus, identified the DmtA methyltransferase from A. flavus, and produced a dmtA knock-out mutant by replacing the dmtA coding sequence with the pyrG selectable marker. The A. flavus dmtA null mutant lines produced white fluffy mycelium in liquid medium, and displayed a slightly flavescent conidial pigmentation compared with the normal yellow of the wild-type strain when grown on agar. The ΔdmtA lines exhibited decreased conidiation and aflatoxin (AF) biosynthesis, compared with the wild-type line, suggesting that the DmtA knock-out affected the transcriptional level of genes in the AF cluster. In particular, sclerotia development and host colonization were altered in the dmtA null mutants. Green fluorescent protein tagging at the C-terminus of DmtA showed that DmtA localized to the nucleus and cytoplasm. DNA methylation content measurements in the dmtA mutants revealed no widespread DNA methylation in the mutants or wild-type lines. Thus, our findings suggest that DmtA, apart from being a C-5 cytosine methyltransferase in A. flavus, contributes to asexual development, aflatoxin biosynthesis, sclerotial production and virulence. PMID:26979781

  9. 75 FR 9596 - Notice of Filing of a Pesticide Petition for Residues of a Aspergillus flavus AF36 on Corn Food...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-03

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Notice of Filing of a Pesticide Petition for Residues of a Aspergillus flavus AF36 on Corn Food... residues of the antifungal ] agent, Aspergillus flavus AF36, in or on corn food and feed commodities....

  10. Antimicrobial effects of ionizing radiation on artificially and naturally contaminated cacao beans. [Aspergillus flavus; Penicillium citrinum

    SciTech Connect

    Restaino, L.; Myron, J.J.J.; Lenovich, L.M.; Bills, S.; Tscherneff, K.

    1984-04-01

    With an initial microbial level of ca. 10/sup 7/ microorganisms per g of Ivory Coast cacao beans, 5 kGy of gamma radiation from a Co/sup 60/ source under an atmosphere of air reduced the microflora per g by 2.49 and 3.03 logs at temperatures of 35 and 50/sup 0/C, respectively. Bahia cacao beans were artificially contaminated with dried spores of Aspergillus flavus and Penicillium citrinum, giving initial fungal levels of 1.9 x 10/sup 4/ and 1.4 x 10/sup 3/ spores per g of whole Bahia cacao beans, respectively. The average D/sub 10/ values for A. flavus and P. citrinum spores on Bahia cacao beans were 0.66 and 0.88 kGy, respectively. 12 references.