Science.gov

Sample records for aflatoxigenic aspergillus flavus

  1. Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields.

    PubMed

    Sebők, Flóra; Dobolyi, Csaba; Zágoni, Dóra; Risa, Anita; Krifaton, Csilla; Hartman, Mátyás; Cserháti, Mátyás; Szoboszlay, Sándor; Kriszt, Balázs

    2016-12-01

    Due to the climate change, aflatoxigenic Aspergillus species and strains have appeared in several European countries, contaminating different agricultural commodities with aflatoxin. Our aim was to screen the presence of aflatoxigenic fungi in maize fields throughout the seven geographic regions of Hungary. Fungi belonging to Aspergillus section Flavi were isolated in the ratio of 26.9% and 42.3% from soil and maize samples in 2013, and these ratios decreased to 16.1% and 34.7% in 2014. Based on morphological characteristics and the sequence analysis of the partial calmodulin gene, all isolates proved to be Aspergillus flavus, except four strains, which were identified as Aspergillus parasiticus. About half of the A. flavus strains and all the A. parasiticus strains were able to synthesize aflatoxins. Aflatoxigenic Aspergillus strains were isolated from all the seven regions of Hungary. A. parasiticus strains were found in the soil of the regions Southern Great Plain and Southern Transdanubia and in a maize sample of the region Western Transdanubia. In spite of the fact that aflatoxins have rarely been detected in feeds and foods in Hungary, aflatoxigenic A. flavus and A. parasiticus strains are present in the maize culture throughout Hungary posing a potential threat to food safety.

  2. Characterization of aflatoxigenic and non-aflatoxigenic Aspergillus flavus isolates from pistachio.

    PubMed

    Hua, Sui Sheng T; McAlpin, Cesaria E; Chang, Perng-Kuang; Sarreal, Siov Bouy L

    2012-02-01

    Pistachio is a popular snack food. Aflatoxin contamination of pistachio nuts is a serious problem for many producing countries. The development of biological control methods based on ecological parameters is an environmentally friendly approach. Thirty-eight Aspergillus flavus isolates collected from a pistachio orchard in California (CA) were analyzed for production of aflatoxin (AF), cyclopiazonic acid (CPA), vegetative compatibility groups (VCGs), and mating types. All aflatoxigenic isolates produced both AFB1 and CPA. The most toxigenic one was CA28 which produced 164 μg AFB1 per 5 ml PDA fungal culture and small sclerotia (S strain, sclertoium size less than 400 μm). The other aflatoxigenic strains produce AFB1 ranging from 1.2 μg to 80 μg per 5 ml fungal culture. Twenty-one percent of the CA isolates produced AFB1, 84% produced CPA and half formed sclerotia on at least one of three tested media. The 38 CA isolates formed 26 VCGs, 6 of which had two or more isolates and 20 contained single isolates. The S strain isolates belong to 4 different VCGs. Genomic profiling by a retrotransposon DNA probe revealed fingerprint patterns that were highly polymorphic. The predicted VCGs (Pred-VCGs) based on a similarity coefficient >80% matched the VCGs of multiple isolates determined by complementation. All isolates within a VCG had the same mating-type gene of either MAT1-1 or MAT1-2. Uncorrected and VCG-corrected MAT1-1 and MAT1-2 among the isolates were equally distributed.

  3. 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...

  4. Inhibitory Effects of Thai Essential Oils on Potentially Aflatoxigenic Aspergillus parasiticus and Aspergillus flavus.

    PubMed

    Jantapan, Kittika; Poapolathep, Amnart; Imsilp, Kanjana; Poapolathep, Saranya; Tanhan, Phanwimol; Kumagai, Susumu; Jermnak, Usuma

    2017-01-01

     The antiaflatoxigenic and antifungal activities of essential oils (EOs) of finger root (Boesenbergia rotunda (L.) Mansf.), pine (Pinus pinaster), rosewood (Aniba rosaedora), Siam benzoin (Styrax tonkinensis), Thai moringa (Moringa oleifera), and ylang ylang (Cananga odorata) were tested for Aspergillus parasiticus and Aspergillus flavus in potato dextrose broth. Aflatoxin B1 (AFB1) was extracted from culture using a QuEChERS-based extraction procedure and analyzed with high performance liquid chromatography (HPLC) coupled to a fluorescence detector. EO of pine showed the greatest inhibition of growth and AFB1 production of A. parasiticus, followed by EOs of rosewood, finger root, Siam benzoin, and ylang ylang. EO of finger root gave the best inhibitory effects on A. flavus, followed by EOs of rosewood, pine, ylang ylang, and Siam benzoin. EO of Thai moringa did not show any significant inhibition of aflatoxigenic fungi. The antiaflatoxigenic activities of EOs correlated with their antifungal activities in the dosedependent manner. Comparison of the application of the five selected EOs in peanut pods by direct and vapor exposure indicated that the AFB1 production inhibitory effects of the five EOs by direct exposure were faster and more effective than by vapor exposure. EO of finger root showed the best inhibition of AFB1 production of A. flavus in peanut pods by direct exposure, followed by EOs of pine, rosewood, ylang ylang, and Siam benzoin.

  5. Reduction of aflatoxins, cyclopiazonic acid and fumonisins in corn by biocontrol strains of non-aflatoxigenic Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of field studies in corn (maize) evaluated the ability of non-aflatoxigenic biocontrol strains of Aspergillus flavus to reduce, through competitive exclusion, production in kernels of aflatoxins and cyclopiazonic acid (CPA) by A. flavus and fumonisins by Fusarium verticillioides. The abili...

  6. 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

  7. Co-inoculating of aflatoxigenic and non-aflatoxigenic strains of Aspergillus flavus to study fungal invasion, colonization, and competition in maize kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A currently utilized pre-harvest bio-control method involves field inoculations with non-aflatoxigenic Aspergillus flavus, a tactic shown to strategically displace the native aflatoxin producing strain and effectively decrease aflatoxin contamination in corn. The present in situ study focuses on tra...

  8. Use of a Granular Bioplastic Formulation for Carrying Conidia of a Non-aflatoxigenic Strain of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research demonstrated that aflatoxin contamination in corn grown in Mississippi is reduced by field application of wheat grains pre-inoculated with the non-aflatoxigenic Aspergillus flavus strain NRRL 30797. To facilitate field applications of the biocontrol isolate, a series of laboratory ...

  9. 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...

  10. Expression of Genes by Aflatoxigenic and Nonaflatoxigenic Strains of Aspergillus flavus Isolated from Brazil Nuts.

    PubMed

    Baquião, Arianne Costa; Rodriges, Aline Guedes; Lopes, Evandro Luiz; Tralamazza, Sabina Moser; Zorzete, Patricia; Correa, Benedito

    2016-08-01

    The aims of the present study were to monitor the production of aflatoxin B1 (AFB1) and mycelial growth, and to evaluate the expression of genes directly and indirectly involved in the biosynthesis of aflatoxins by Aspergillus flavus isolated from Brazil nuts. Six previously identified A. flavus strains were grown on coconut agar at 25°C for up to 10 days. Mycotoxins were separated by high-performance liquid chromatography and fungal growth was measured daily using the diametric mycelial growth rate. Transcriptional analysis was performed by real-time polymerase chain reaction (PCR) after 2 and 7 d of incubation using specific primers (aflR, aflD, aflP, lipase, metalloprotease, and LaeA). Three (50%) of the six A. flavus isolates produced AFB1 (ICB-1, ICB-12, and ICB-54) and three (50%) were not aflatoxigenic (ICB-141, ICB-161, and ICB-198). Aflatoxin production was observed from d 2 of incubation (1.5 ng/g for ICB-54) and increased gradually with time of incubation until d 10 (15,803.6 ng/g for ICB-54). Almost all A. flavus isolates exhibited a similar gene expression pattern after 2 d of incubation (p > 0.10). After 7 d of incubation, the LaeA (p < 0.05) and metalloprotease (p < 0.05) genes were the most expressed by nonaflatoxigenic strains, whereas aflatoxigenic isolates exhibited higher expression of the aflR (p < 0.05) and aflD genes (p < 0.05). Our results suggest that the expression of aflR and aflD is correlated with aflatoxin production in A. flavus and that overexpression of aflR could affect the transcriptional and aflatoxigenic pattern (ICB-54). Elucidation of the molecular mechanisms that regulate the secondary metabolism of toxigenic fungi may permit the rational silencing of the genes involved and consequently the programmed inhibition of aflatoxin production. Knowledge of the conditions, under which aflatoxin genes are expressed, should contribute to the development of innovative and more cost-effective strategies to

  11. 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...

  12. Comparison of major biocontrol strains of non-aflatoxigenic Aspergillus flavus for the reduction of aflatoxins and cyclopiazonic acid in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of toxigenic Aspergillus flavus in maize through competitive displacement by non-aflatoxigenic strains was evaluated in a series of field studies. Four sets of experiments were conducted between 2007 to 2009 to assess the competitiveness of non-aflatoxigenic strains when challen...

  13. Co-inoculation of aflatoxigenic and non-aflatoxigenic strains of Aspergillus flavus to study fungal invasion, colonization, and competition in maize kernels.

    PubMed

    Hruska, Zuzana; Rajasekaran, Kanniah; Yao, Haibo; Kincaid, Russell; Darlington, Dawn; Brown, Robert L; Bhatnagar, Deepak; Cleveland, Thomas E

    2014-01-01

    A currently utilized pre-harvest biocontrol method involves field inoculations with non-aflatoxigenic Aspergillus flavus strains, a tactic shown to strategically suppress native aflatoxin-producing strains and effectively decrease aflatoxin contamination in corn. The present in situ study focuses on tracking the invasion and colonization of an aflatoxigenic A. flavus strain (AF70), labeled with green fluorescent protein (GFP), in the presence of a non-aflatoxigenic A. flavus biocontrol strain (AF36), to better understand the competitive interaction between these two strains in seed tissue of corn (Zea mays). Corn kernels that had been co-inoculated with GFP-labeled AF70 and wild-type AF36 were cross-sectioned and observed under UV and blue light to determine the outcome of competition between these strains. After imaging, all kernels were analyzed for aflatoxin levels. There appeared to be a population difference between the co-inoculated AF70-GFP+AF36 and the individual AF70-GFP tests, both visually and with pixel count analysis. The GFP allowed us to observe that AF70-GFP inside the kernels was suppressed up to 82% when co-inoculated with AF36 indicating that AF36 inhibited progression of AF70-GFP. This was in agreement with images taken of whole kernels where AF36 exhibited a more robust external growth compared to AF70-GFP. The suppressed growth of AF70-GFP was reflected in a corresponding (upto 73%) suppression in aflatoxin levels. Our results indicate that the decrease in aflatoxin production correlated with population depression of the aflatoxigenic fungus by the biocontrol strain supporting the theory of competitive exclusion through robust propagation and fast colonization by the non-aflatoxigenic fungus.

  14. Mechanisms of antifungal and anti-aflatoxigenic properties of essential oil derived from turmeric (Curcuma longa L.) on Aspergillus flavus.

    PubMed

    Hu, Yichen; Zhang, Jinming; Kong, Weijun; Zhao, Gang; Yang, Meihua

    2017-04-01

    The antifungal activity and potential mechanisms in vitro as well as anti-aflatoxigenic efficiency in vivo of natural essential oil (EO) derived from turmeric (Curcuma longa L.) against Aspergillus flavus was intensively investigated. Based on the previous chemical characterization of turmeric EO by gas chromatography-mass spectrometry, the substantially antifungal activities of turmeric EO on the mycelial growth, spore germination and aflatoxin production were observed in a dose-dependent manner. Furthermore, these antifungal effects were related to the disruption of fungal cell endomembrane system including the plasma membrane and mitochondria, specifically i.e. the inhibition of ergosterol synthesis, mitochondrial ATPase, malate dehydrogenase, and succinate dehydrogenase activities. Moreover, the down-regulation profiles of turmeric EO on the relative expression of mycotoxin genes in aflatoxin biosynthetic pathway revealed its anti-aflatoxigenic mechanism. Finally, the suppression effect of fungal contamination in maize indicated that turmeric EO has potential as an eco-friendly antifungal agent.

  15. 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...

  16. Aflatoxin B1 Degradation by Metabolites of Phoma glomerata PG41 Isolated From Natural Substrate Colonized by Aflatoxigenic Aspergillus flavus

    PubMed Central

    Shcherbakova, Larisa; Statsyuk, Natalia; Mikityuk, Oleg; Nazarova, Tatyana; Dzhavakhiya, Vitaly

    2015-01-01

    Background: Aflatoxin B1 (AFB1), produced by Aspergillus flavus, is one of the most life threatening food contaminants causing significant economic losses worldwide. Biological AFB1 degradation by microorganisms, or preferably microbial enzymes, is considered as one of the most promising approaches. Objectives: The current work aimed to study the AFB1-degrading metabolites, produced by Phoma glomerata PG41, sharing a natural substrate with aflatoxigenic A. flavus, and the preliminary determination of the nature of these metabolites. Materials and Methods: The AFB1-degrading potential of PG41 metabolites was determined by a quantitative high performance liquid chromatography (HPLC) of residual AFB1 after 72 hours incubation at 27ºC. The effects of pH, heat, and protease treatment on the AFB1-destroying activity of extracellular metabolites were examined. Results: The AFB1-degrading activity of protein-enriched fractions, isolated from culture liquid filtrate and cell-free extract, is associated with high-molecular-weight components, is time- and pH-dependent, thermolabile, and is significantly reduced by proteinase K treatment. The AFB1 degradation efficiency of these fractions reaches 78% and 66%, respectively. Conclusions: Phoma glomerata PG41 strain sharing natural substrate with toxigenic A. flavus secretes metabolites possessing a significant aflatoxin-degrading activity. The activity is associated mainly with a protein-enriched high-molecular-weight fraction of extracellular metabolites and appears to be of enzymatic origin. PMID:25789135

  17. Use of a granular bioplastic formulation for carrying conidia of a non-aflatoxigenic strain of Aspergillus flavus.

    PubMed

    Accinelli, Cesare; Saccà, M Ludovica; Abbas, Hamed K; Zablotowicz, Robert M; Wilkinson, Jeffery R

    2009-09-01

    Previous research demonstrated that aflatoxin contamination in corn is reduced by field application of wheat grains pre-inoculated with the non-aflatoxigenic Aspergillus flavus strain NRRL 30797. To facilitate field applications of this biocontrol isolate, a series of laboratory studies were conducted on the reliability and efficiency of replacing wheat grains with the novel bioplastic formulation Mater-Bi to serve as a carrier matrix to formulate this fungus. Mater-Bi granules were inoculated with a conidial suspension of NRRL 30797 to achieve a final cell density of approximately log 7 conidia/granule. Incubation of 20-g soil samples receiving a single Mater-Bi granule for 60-days resulted in log 4.2-5.3 propagules of A. flavus/g soil in microbiologically active and sterilized soil, respectively. Increasing the number of granules had no effect on the degree of soil colonization by the biocontrol fungus. In addition to the maintenance of rapid vegetative growth and colonization of soil samples, the bioplastic formulation was highly stable, indicating that Mater-Bi is a suitable substitute for biocontrol applications of A. flavus NRRL 30797.

  18. 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

  19. Non-aflatoxigenic Aspergillus flavus to prevent aflatoxin contamination in crops: advantages and limitations

    PubMed Central

    Ehrlich, Kenneth C.

    2014-01-01

    Aspergillus flavus is a diverse assemblage of strains that include aflatoxin-producing and non-toxigenic strains with cosmopolitan distribution. The most promising strategy currently being used to reduce preharvest contamination of crops with aflatoxin is to introduce non-aflatoxin (biocontrol) A. flavus into the crop environment. Whether or not introduction of biocontrol strains into agricultural fields is enough to reduce aflatoxin contamination to levels required for acceptance of the contaminated food as fit for consumption is still unknown. There is no question that biocontrol strains are able to reduce the size of the populations of aflatoxin-producing strains but the available data suggests that at most only a four- to five-fold reduction in aflatoxin contamination is achieved. There are many challenges facing this strategy that are both short term and long term. First, the population biology of A. flavus is not well understood due in part to A. flavus’s diversity, its ability to form heterokaryotic reproductive forms, and its unknown ability to survive for prolonged periods after application. Second, biocontrol strains must be selected that are suitable for the environment, the type of crop, and the soil into which they will be introduced. Third, there is a need to guard against inadvertent introduction of A. flavus strains that could impose an additional burden on food safety and food quality, and fourth, with global warming and resultant changes in the soil nutrients and concomitant microbiome populations, the biocontrol strategy must be sufficiently flexible to adapt to such changes. Understanding genetic variation within strains of A. flavus is important for developing a robust biocontrol strategy and it is unlikely that a “one size fits all” strategy will work for preharvest aflatoxin reduction. PMID:24575088

  20. RNA interference-mediated control of Aspergillus flavus in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Aflatoxigenic Aspergillus flavus is a frequent contaminant of agricultural commodities such as corn, peanut, tree nuts and cottonseed. Ingestion of foods, especially corn, contaminated with aflatoxins has been implicated in acute toxicoses while chronic, low-level exposure can lead to...

  1. 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...

  2. Distribution of aflatoxigenic Aspergillus section Flavi in commercial poultry feed in Nigeria.

    PubMed

    Ezekiel, C N; Atehnkeng, J; Odebode, A C; Bandyopadhyay, R

    2014-10-17

    The distribution and aflatoxigenicity of Aspergillus section Flavi isolates in 58 commercial poultry feed samples obtained from 17 states in five agro-ecological zones (AEZs) in Nigeria were determined in order to assess the safety of the feeds with respect to aflatoxin-producing fungi. Correlation was also performed for incidence of species, aflatoxin-producing ability of isolates in vitro, and aflatoxin (AFB1) concentrations in the feed. A total of 1006 Aspergillus section Flavi isolates were obtained from 87.9% of the feed samples and identified as Aspergillus flavus, unnamed taxon SBG, Aspergillus parasiticus and Aspergillus tamarii. A. flavus was the most prevalent (91.8%) of the isolates obtained from the feed in the AEZs while A. parasiticus had the lowest incidence (0.1%) and was isolated only from a layer mash sample collected from the DS zone. About 29% of the Aspergillus isolates produced aflatoxins in maize grains at concentrations up to 440,500μg/kg B and 341,000μg/kgG aflatoxins. The incidence of toxigenic isolates was highest (44.4%) in chick mash and lowest (19.9%) in grower mash. The population of A. flavus in the feed had positive (r=0.50) but non significant (p>0.05) correlations with proportion of toxigenic isolates obtained from the feed while SBG had significant (p<0.001) positive (r=0.99) influence on AFB1 concentrations in the feed. Poultry feed in Nigerian markets are therefore highly contaminated with aflatoxigenic Aspergillus species and consequently, aflatoxins. This is a potential threat to the poultry industry and requires urgent intervention.

  3. Assessment of aflatoxigenic Aspergillus and other fungi in millet and sesame from Plateau State, Nigeria

    PubMed Central

    Ezekiel, C.N.; Udom, I.E.; Frisvad, J.C.; Adetunji, M.C.; Houbraken, J.; Fapohunda, S.O.; Samson, R.A.; Atanda, O.O.; Agi-Otto, M.C.; Onashile, O.A.

    2014-01-01

    Sixteen fonio millet and 17 sesame samples were analysed for incidence of moulds, especially aflatoxigenic Aspergillus species, in order to determine the safety of both crops to consumers, and to correlate aflatoxin levels in the crops with levels produced by toxigenic isolates on laboratory medium. Diverse moulds including Alternaria, Aspergillus, Cercospora, Fusarium, Mucor, Penicillium, Rhizopus and Trichoderma were isolated. Aspergillus was predominantly present in both crops (46–48%), and amongst the potentially aflatoxigenic Aspergillus species, A. flavus recorded the highest incidence (68% in fonio millet; 86% in sesame kernels). All A. parvisclerotigenus isolates produced B and G aflatoxins in culture while B aflatoxins were produced by only 39% and 20% of A. flavus strains isolated from the fonio millet and sesame kernels, respectively. Aflatoxin concentrations in fonio millet correlated inversely (r = −0.55; p = 0.02) with aflatoxin levels produced by toxigenic isolates on laboratory medium, but no correlation was observed in the case of the sesame samples. Both crops, especially sesame, may not be suitable substrates for aflatoxin biosynthesis. This is the first report on A. parvisclerotigenus in sesame. PMID:24772370

  4. 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...

  5. Clonality and sex impact aflatoxigenicity in Aspergillus populations

    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 are aflatoxins. Aspergillus flavus is the dominant aflatoxin-producing species in the majority of crops. Populatio...

  6. 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...

  7. 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

    2016-01-04

    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.

  8. Draft Genome Sequence of an Aflatoxigenic Aspergillus Species, A. bombycis

    PubMed Central

    Moore, Geromy G.; Mack, Brian M.; Beltz, Shannon B.; Gilbert, Matthew K.

    2016-01-01

    Aspergillus bombycis was first isolated from silkworm frass in Japan. It has been reportedly misidentified as A. nomius due to their macro-morphological and chemotype similarities. We sequenced the genome of the A. bombycis Type strain and found it to be comparable in size (37 Mb), as well as in numbers of predicted genes (12,266), to other sequenced Aspergilli. The aflatoxin gene cluster in this strain is similar in size and the genes are oriented the same as other B- + G-aflatoxin producing species, and this strain contains a complete but nonfunctional gene cluster for the production of cyclopiazonic acid. Our findings also showed that the A. bombycis Type strain contains a single MAT1-2 gene indicating that this species is likely heterothallic (self-infertile). This draft genome will contribute to our understanding of the genes and pathways necessary for aflatoxin synthesis as well as the evolutionary relationships of aflatoxigenic fungi. PMID:27664179

  9. 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...

  10. Aspergillus flavus: The Major Producer of Aflatoxin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is an opportunistic pathogen of crops. It is important because it produces aflatoxin as a secondary metabolite in the seeds of a number of crops both before and after harvest. Aflatoxin is a potent carcinogen that is highly regulated in most countries. In the field, aflatoxin i...

  11. 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...

  12. 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.

  13. Evolutionary relationships among Aspergillus flavus vegetative compatibility groups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a fungal plant pathogen of many diverse crops including cotton, peanuts, maize, almond, and pistachio. During infection by A. flavus, crops are frequently contaminated with highly carcinogenic aflatoxins. A. flavus populations are composed of numerous vegetative compatibility g...

  14. 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...

  15. 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...

  16. Draft genome sequence of an aflatoxigenic Aspergillus species, A. bombycis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of the A. bombycis Type strain was sequenced using a Personal Genome Machine, followed by annotation of its predicted genes. The genome size for A. bombycis was found to be approximately 37 Mb and contained 12,266 genes. This announcement introduces a sequenced genome for an aflatoxigenic...

  17. 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...

  18. 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...

  19. 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...

  20. 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 ...

  1. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Aspergillus flavus AF36; exemption... FOOD Exemptions From Tolerances § 180.1206 Aspergillus flavus AF36; exemption from the requirement of a... pesticide Aspergillus flavus AF36 in or on cotton, gin byproducts; cotton, hulls; cotton, meal;...

  2. 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.

  3. Genomic sequence for the aflatoxigenic filamentous fungus Aspergillus nomius

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of the A. nomius type strain was sequenced using a personal genome machine. Annotation of the genes was undertaken, followed by gene ontology and an investigation into the number of secondary metabolite clusters. Comparative studies with other Aspergillus species involved shared/unique ge...

  4. Genomic sequence of the aflatoxigenic filamentous fungus Aspergillus nomius

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus nomius is an opportunistic pathogen and one of the three most important producers of aflatoxins in section Flavi. This fungus has been reported to contaminate agricultural commodities, but it has also been sampled in non-agricultural soils so the host range is not well known. Having a si...

  5. Aflatoxin production and oxidative stress in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The colonization of crops by Aspergillus flavus results in the production of aflatoxins. Aflatoxin production is also exacerbated by abiotic stresses in the field. Here, we investigated the role of reactive oxygen species (ROS), which accumulate in plant tissues in response to drought and heat stres...

  6. 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...

  7. 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...

  8. 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...

  9. Aflatoxigenic Fungi and Aflatoxins in Portuguese Almonds

    PubMed Central

    Rodrigues, P.; Venâncio, A.; Lima, N.

    2012-01-01

    Aflatoxin contamination of nuts is an increasing concern to the consumer's health. Portugal is a big producer of almonds, but there is no scientific knowledge on the safety of those nuts, in terms of mycotoxins. The aim of this paper was to study the incidence of aflatoxigenic fungi and aflatoxin contamination of 21 samples of Portuguese almonds, and its evolution throughout the various stages of production. All fungi belonging to Aspergillus section Flavi were identified and tested for their aflatoxigenic ability. Almond samples were tested for aflatoxin contamination by HPLC-fluorescence. In total, 352 fungi belonging to Aspergillus section Flavi were isolated from Portuguese almonds: 127 were identified as A. flavus (of which 28% produced aflatoxins B), 196 as typical or atypical A. parasiticus (all producing aflatoxins B and G), and 29 as A. tamarii (all nonaflatoxigenic). Aflatoxins were detected in only one sample at 4.97 μg/kg. PMID:22666128

  10. 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...

  11. 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...

  12. 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.

  13. Aspergillus flavus impairs antioxidative enzymes of Sternochetus mangiferae during mycosis.

    PubMed

    Jayanthi, Kamala P D; Ayyasamy, Arthikirubha; Kempraj, Vivek; Aurade, Ravindra M; Govindan, Selvakumar; Verghese, Abraham

    2015-01-01

    Insects depend upon cuticular, humoral and cellular defenses to resist mycosis. However, entomopathogenic fungi through co-evolution have developed mechanisms to counter such defenses. Although a plethora of mechanisms of mycosis by entomopathogenic fungi are well-established, studies on the impairment of insects' antioxidative enzymes during mycosis remain elusive. Here, we used the interaction of Sternochetus mangiferae and its associated entomopathogenic fungus, Aspergillus flavus, as a model to validate our hypothesis. Uninfected insects were exposed to fungal spores for infection to occur. We observed symptoms of mycosis within 48 h of incubation period. Biochemical studies on antioxidative enzymes namely catalase, peroxidase and phenoloxidase, in infected and uninfected insects revealed decreased activity of these enzymes. It appears that A. flavus disables the host's antioxidative enzyme system that plays a crucial role in elimination of oxidative toxins produced during mycosis.

  14. Expression profiling of non-aflatoxigenic Aspergillus parasiticus mutants obtained by 5-azacytosine treatment or serial mycelial transfer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and Aspergillus parasiticus. Repeated serial mycelial transfer or treatment of A. parasiticus with 5-azacytidine produced mutants with a fluffy phenotype and loss of aflatoxin production. To understand how the...

  15. 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...

  16. 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

  17. Chemoprevention by essential oil of turmeric leaves (Curcuma longa L.) on the growth of Aspergillus flavus and aflatoxin production.

    PubMed

    Sindhu, S; Chempakam, B; Leela, N K; Suseela Bhai, R

    2011-05-01

    Turmeric is well known for a wide range of medicinal properties. Essential oil of turmeric leaves (Curcuma longa L.) were evaluated at varying concentrations of 0.01, 0.05, 0.1, 0.5, 0.75, 1.0 and 1.5% (v/v) in Yeast Extract Sucrose (YES) broth inoculated with spore suspension of Aspergillus flavus of 10(6)conidia/ml. These were evaluated for their potential in the control of aflatoxigenic fungus A. flavus and aflatoxin production. Turmeric leaf oil exhibited 95.3% and 100% inhibition of toxin production respectively at 1.0% and 1.5%. The extent of inhibition of fungal growth and aflatoxin production was dependent on the concentration of essential oil used. The oil exhibited significant inhibition of fungal growth as well as aflatoxins B(1) and G(1) production. The LD(50) and LD(90) were also determined. GC-MS analysis of the oil showed α-phellandrene, p-cymene and terpinolene as the major components in turmeric leaf oil. The possibility of using these phytochemical components as bio-preservatives for storage of spices is discussed.

  18. Aflatoxin production by entomopathogenic isolates of Aspergillus parasiticus and Aspergillus flavus.

    PubMed

    Drummond, J; Pinnock, D E

    1990-05-01

    Fourteen isolates of Aspergillus parasiticus and 2 isolates of Aspergillus flavus isolated from the mealybug Saccharicoccus sacchari were analyzed for production of aflatoxins B1, B2, G1, and G2 in liquid culture over a 20-day period. Twelve Aspergillus isolates including 11 A. parasiticus and 1 A. flavus produced aflatoxins which were extracted from both the mycelium and culture filtrate. Aflatoxin production was detected at day 3 and was detected continually for up to day 20. Aflatoxin B1 production was greatest between 7 and 10 days and significantly higher quantities were produced by A. flavus compared to A. parasiticus. Aflatoxin production was not a stable trait in 1 A. parasiticus isolate passaged 50 times on agar. In addition to loss of aflatoxin production, an associated loss in sporulation ability was also observed in this passaged isolate, although it did maintain pathogenicity against S. sacchari. An aflatoxin B1 concentration of 0.16 micrograms/mealybug (14.2 micrograms/g wet wt) was detected within the tissues of infected mealybugs 7 days after inoculation. In conclusion, the ability of Aspergillus isolates to produce aflatoxins was not essential to the entomopathogenic activity of this fungus against its host S. sacchari.

  19. Reduction of aflatoxin production by Aspergillus flavus and Aspergillus parasiticus in interaction with Streptomyces.

    PubMed

    Verheecke, C; Liboz, T; Anson, P; Diaz, R; Mathieu, F

    2015-05-01

    The aim of this study is to investigate aflatoxin gene expression during Streptomyces-Aspergillus interaction. Aflatoxins are carcinogenic compounds produced mainly by Aspergillus flavus and Aspergillus parasiticus. A previous study has shown that Streptomyces-A. flavus interaction can reduce aflatoxin content in vitro. Here, we first validated this same effect in the interaction with A. parasiticus. Moreover, we showed that growth reduction and aflatoxin content were correlated in A. parasiticus but not in A. flavus. Secondly, we investigated the mechanisms of action by reverse-transcriptase quantitative PCR. As microbial interaction can lead to variations in expression of household genes, the most stable [act1, βtub (and cox5 for A. parasiticus)] were chosen using geNorm software. To shed light on the mechanisms involved, we studied during the interaction the expression of five genes (aflD, aflM, aflP, aflR and aflS). Overall, the results of aflatoxin gene expression showed that Streptomyces repressed gene expression to a greater level in A. parasiticus than in A. flavus. Expression of aflR and aflS was generally repressed in both Aspergillus species. Expression of aflM was repressed and was correlated with aflatoxin B1 content. The results suggest that aflM expression could be a potential aflatoxin indicator in Streptomyces species interactions. Therefore, we demonstrate that Streptomyces can reduce aflatoxin production by both Aspergillus species and that this effect can be correlated with the repression of aflM expression.

  20. 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. Elmitwalli; Fatma, Helmi M.; Rizk, Mohammed A.; Hagrassy, Abeer F.

    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.

  1. 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...

  2. 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.

  3. 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...

  4. 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...

  5. Transcriptomic profiling of decanal effects on Aspergillus flavus gene expression in development and secondary metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a saprophyte and an opportunistic plant pathogen. It is capable of producing carcinogenic aflatoxins. We treated A. flavus CA42 with the volatile decanal and analyzed changes in the transcriptomic profiles at different stages of growth and development. Paired-end RNA-Seq reads ...

  6. 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...

  7. Degeneration of aflatoxin gene cluster in Aspergillus flavus from Africa and North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is the primary causal agent of food and feed contamination with the toxic fungal metabolites aflatoxins. Aflatoxin-producing potential of A. flavus is known to vary among isolates. The genes involved in aflatoxin biosynthesis are clustered together and the order of genes within th...

  8. 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. ...

  9. Ageratum conyzoides essential oil as aflatoxin suppressor of Aspergillus flavus.

    PubMed

    Nogueira, Juliana H C; Gonçalez, Edlayne; Galleti, Silvia R; Facanali, Roseane; Marques, Márcia O M; Felício, Joana D

    2010-01-31

    Aflatoxin B(1) (AFB(1)) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oil of Ageratum conyzoides, on the mycelial growth and aflatoxin B(1) production by Aspergillus flavus were studied. Cultures were incubated in yeast extract-sucrose (YES) broth for days at 25 degrees C at the following different concentrations of the essential oil (from 0.0 to 30mug/mL). The essential oil inhibited fungal growth to different extents depending on the concentration, and completely inhibited aflatoxin production at concentrations above 0.10microg/mL. The analysis of the oil by GC/MS showed that its main components are precocene II (46.35%), precocene I (42.78%), cumarine (5.01%) and Trans-caryophyllene (3.02%). Comparison by transmission electron microscopy of the fungal cells, control and those incubated with different concentrations of essential oil, showed ultra-structural changes which were concentration dependent of the essential oil of A. conyzoides. Such ultra-structural changes were more evident in the endomembrane system, affecting mainly the mitochondria. Degradation was also observed in both surrounding fibrils. The ability to inhibit aflatoxin production as a new biological activity of A.conyzoides L. indicates that it may be considered as a useful tool for a better understanding of the complex pathway of aflatoxin biosynthesis.

  10. Modelling Aspergillus flavus growth and aflatoxins production in pistachio nuts.

    PubMed

    Marín, Sonia; Ramos, Antonio J; Sanchis, V

    2012-12-01

    Aflatoxins (AFs) are the main contaminants in pistachio nuts. AFs production in pistachio has been attributed to Aspergillus flavus. The aim of this study was to apply existing models to predict growth and AFs production by an A. flavus isolated from pistachios as a function of moisture content and storage temperature of pistachios in order to test their usefulness and complementarities. A full factorial design was used: the moisture content levels assayed were 10, 15, 20, 25 and 30% and incubation temperatures were 10, 15, 20, 25, 30, 37 and 42 °C. Both kinetic and probability models were built to predict growth of the strain under the assayed conditions. Among the assayed models, cardinal ones gave a good quality fit for radial growth rate data. Moreover, the progressive approach, which was developed based on a reduced number of experimental points led to an improved prediction in the validation step. This is quite significant as may allow for improved experimental designs, less costly than full factorial ones. Probability model proved to be concordant in 91% of the calibration set observations. Even though the validation set included conditions around the growth/no-growth interface, there was a 100% agreement in the predictions from the data set (n = 16, cut off = 0.5) after 60 days. Similarly, the probability for AF presence was rightly predicted in 89% of the cases. According to our results EC maximum aflatoxin levels would be surpassed in a period as short as 1 month if pistachio nuts reach 20 °C, unless %mc is ≤10%.

  11. An attempt to model the probability of growth and aflatoxin B1 production of Aspergillus flavus under non-isothermal conditions in pistachio nuts.

    PubMed

    Aldars-García, Laila; Ramos, Antonio J; Sanchis, Vicente; Marín, Sonia

    2015-10-01

    Human exposure to aflatoxins in foods is of great concern. The aim of this work was to use predictive mycology as a strategy to mitigate the aflatoxin burden in pistachio nuts postharvest. The probability of growth and aflatoxin B1 (AFB1) production of aflatoxigenic Aspergillus flavus, isolated from pistachio nuts, under static and non-isothermal conditions was studied. Four theoretical temperature scenarios, including temperature levels observed in pistachio nuts during shipping and storage, were used. Two types of inoculum were included: a cocktail of 25 A. flavus isolates and a single isolate inoculum. Initial water activity was adjusted to 0.87. Logistic models, with temperature and time as explanatory variables, were fitted to the probability of growth and AFB1 production under a constant temperature. Subsequently, they were used to predict probabilities under non-isothermal scenarios, with levels of concordance from 90 to 100% in most of the cases. Furthermore, the presence of AFB1 in pistachio nuts could be correctly predicted in 70-81 % of the cases from a growth model developed in pistachio nuts, and in 67-81% of the cases from an AFB1 model developed in pistachio agar. The information obtained in the present work could be used by producers and processors to predict the time for AFB1 production by A. flavus on pistachio nuts during transport and storage.

  12. 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...

  13. 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...

  14. RmtA, a putative arginine 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...

  15. 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...

  16. Potential for aflatoxin B1 and B2 production by Aspergillus flavus strains isolated from rice samples

    PubMed Central

    Lai, Xianwen; Zhang, He; Liu, Ruicen; Liu, Chenglan

    2014-01-01

    In this study, we investigated the potential for aflatoxin B1 (AFB1) and B2 (AFB2) production in rice grain by 127 strains of Aspergillus flavus isolated from rice grains collected from China. These strains were inoculated onto rice grains and incubated at 28 °C for 21 days. AFB1 and AFB2 were extracted and quantified by high-performance liquid chromatography coupled with fluorescence detection. Among the tested strains, 37% produced AFB1 and AFB2 with levels ranging from 175 to 124 101 μg kg−1 for AFB1 and from not detected to 10 329 μg kg−1 for AFB2. The mean yields of these isolates were 5884 μg kg−1 for AFB1 and 1968 μg kg−1 for AFB2. Overall, most of the aflatoxigenic strains produced higher levels of AFB1 than AFB2 in rice. The obtained information is useful for assessing the risk of aflatoxin contamination in rice samples. PMID:25737649

  17. Production and characterization of a bioflocculant produced by Aspergillus flavus.

    PubMed

    Aljuboori, Ahmad H Rajab; Idris, Azni; Abdullah, Norhafizah; Mohamad, Rosfarizan

    2013-01-01

    The production and characterization of a bioflocculant, IH-7, by Aspergillus flavus was investigated. About 0.4 g of purified bioflocculant with an average molecular weight of 2.574 × 10(4)Da could be obtained from 1L of fermentation medium. The bioflocculant mainly consisted of protein (28.5%) and sugar (69.7%), including 40% of neutral sugar, 2.48% of uronic acid and 1.8% amino sugar. The neutral sugar components are sucrose, lactose, glucose, xylose, galactose, mannose and fructose at a molar ratio of 2.4:4.4:4.1:5.8:9.9:0.8:3.1. Fourier-transform infrared spectroscopy analysis revealed that purified IH-7 contained hydroxyl, amide, carboxyl and methoxyl groups. The elemental analysis of purified IH-7 showed that the weight fractions of the elements C, H, O, N and S were 29.9%, 4.8%, 34.7%, 3.3%, and 2.0%, respectively. IH-7 had good flocculating rate in kaolin suspension without cation addition and stable over wide range of pH and temperature.

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

    PubMed

    Narayanan, Karthik; Parameswaran, Binod; Pandey, Ashok

    2016-07-03

    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.

  19. 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...

  20. Bioaccumulation potential of Aspergillus niger and Aspergillus flavus for removal of heavy metals from paper mill effluent.

    PubMed

    Thippeswamy, B; Shivakumar, C K; Krishnappa, M

    2012-11-01

    In the present study Aspergillus niger and Aspergillus flavus isolated from paper mill effluent showed tolerance and accumulation of toxic metals Ni, Zn, Cd, Pb, Cr and Cu from synthetic medium and paper mill effluent. Physico-chemical and heavy metals characterization of industrially treated paper mill effluent showed insignificant reduction in BOD, hardness, TDS and heavy metals as compared to permissible limits of BIS and WHO. A. niger and A. flavus were treated with synthetic medium containing 100-1000 mg l(-1) of six heavy metals. A. niger was able to tolerate and grow in 1000 mg l(-1) Pb, 500 mg l(-1) Cu, 250 mg l(-1) Zn and 100 mg l(-1) Cr, Ni respectively. No growth of A. niger was observed in 100 mg l-(-1) of Cd. A. flavus was capable to tolerate and grow in 1000 mg l(-1) Pb, Zn and Ni, 100mg l(-1) Cu. A. flavus growth was completely inhibited in 100 mg l(-1) of Cd and Cr. The Cd, Zn, Cu and Pb reduction were found significant (p < 0.05) in the paper effluent inoculated with A. niger and A. flavus biomass compared to industrial treated effluent. A. niger and A. flavus accumulated maximum of Pb (75.82%) followed by Zn (49.40%) > Cu (45.34%) > Ni (25.20%), while only 41% Cr was accumulated by A. nigerfrom 100 mg l(-1) of Cr solution.

  1. 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.

  2. 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...

  3. 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

  4. Effect of Equisetum arvense and Stevia rebaudiana extracts on growth and mycotoxin production by Aspergillus flavus and Fusarium verticillioides in maize seeds as affected by water activity.

    PubMed

    Garcia, Daiana; Ramos, Antonio J; Sanchis, Vicente; Marín, Sonia

    2012-02-01

    Cereals are a very important part of the human and animal diets. However, agricultural products can be contaminated by moulds and their mycotoxins. Plant extracts, particularly those of Equisetum arvense and Stevia rebaudiana have been reported previously to contain antioxidant compounds which may have antifungal properties. In this study, E. arvense and S. rebaudiana extracts were tested for their control of mycotoxigenic fungi in maize. The extracts were tested separately and as a mixture for their effect on growth of Aspergillus flavus and Fusarium verticillioides. Extracts were added to unsterilised inoculated maize at different water activity (a(w)) levels (0.85-0.95). Moulds were inoculated and incubated for 30 days. Results confirmed that the extract of E. arvense and a mixture 1:1 of Equisetum-Stevia may be effective for the inhibition of both growth of A. flavus and aflatoxin production at high water activity levels (pre-harvest conditions). In general, growth of the F. verticillioides was reduced by the use of plant extracts, especially at 0.95 a(w). However, fumonisin presence was not significantly affected. E. arvense and S. rebaudiana extracts could be developed as an alternative treatment to control aflatoxigenic mycobiota in moist maize.

  5. Xerophilic aflatoxigenic black tea fungi and their inhibition by Elettaria cardamomum and Syzygium aromaticum extracts.

    PubMed

    Al-Sohaibani, Saleh; Murugan, K; Lakshimi, G; Anandraj, K

    2011-10-01

    Black tea is consumed worldwide and is believed to play a role in cancer prevention. Xerophilic aflatoxigenic fungi are highly hazardous contaminants of tea since they are associated with tea quality impairment and human health risk. The present study reports isolation of such xerophilic and aflatoxigenic fungi associated with marketed tea. Twenty different tea samples collected from the local markets of Tamilnadu, India were investigated for fungal contamination. The results indicated contamination by 0.38% Aspergillus flavus. Other common contaminant fungi including Penicillium spp. (0.30%), Pacelomyces spp. (0.14%), and Mucor spp. (0.19%) were also isolated. Amongst the fungi isolated Aspergillus niger ML01 and A. flavus ML02 were found to be xerophilic aflatoxigenic mycoflora. Phylogenetic analysis based on 28S rRNA revealed their close ancestry. The chloroform and acetone extracts of spices Elettaria cardamomum and Syzygium aromaticum exhibited antifungal inhibitory activity on growth and toxin elaboration of both these xerophilic tea contaminants A. niger ML01 and A. flavus ML02. The results advocate the use of these spices plant or their extracts as novel antimicrobials which may add preservation and flavour in marketed tea.

  6. 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,...

  7. 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,...

  8. 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,...

  9. 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...

  10. Oxidative stress and carbon metabolism influence Aspergillus flavus transcriptome composition and secondary metabolite production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of crops with aflatoxin is a serious threat to global food safety. Aflatoxin production by Aspergillus flavus has been shown to be exacerbated by drought stress in the field and by oxidative stress in vitro. We examined the transcriptomes of three toxigenic and three atoxigenic isolate...

  11. 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...

  12. Use of functional genomics to assess the climate change impact on Aspergillus flavus and aflatoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is an opportunistic pathogenic fungus that infects several crops of agricultural importance, among them, corn, cotton, and peanuts. Once established as a pathogen the fungus may secrete secondary metabolites commonly known as mycotoxins, that if consumed by humans or animals may r...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. Quantitative trait loci (QTL) for reducing Aspergillus flavus infection and aflatoxin accumulation in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin produced by Aspergillus flavus in corn poses significant health risks for both humans and livestock. Corn growers suffer huge economic losses due to increased aflatoxin accumulation in grain especially under drought and higher temperature stress conditions. Exploitation of host plant resi...

  18. 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...

  19. 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...

  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. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. Farnesol induces apoptosis-like cell death in the pathogenic fungus Aspergillus flavus.

    PubMed

    Wang, Xiaoyun; Wang, Youzhi; Zhou, Yuguang; Wei, Xinli

    2014-01-01

    Farnesol (FOH) is known to induce apoptosis in some fungi and mammalian cells. We treated Aspergillus flavus, one of the leading causes of human invasive aspergillosis and a key producer of the most potent naturally occurring hepatocarcinogenic compounds, with FOH to assess its effect on the viability of the fungus. FOH strongly inhibited germination and growth of A. flavus and induced markers for apoptosis including nuclear condensation, phosphatidylserine (PS) externalization, DNA fragmentation and intracellular reactive oxygen species (ROS) generation, metacaspase activation and abnormal cellular ultrastructure. Moreover, FOH-induced apoptosis in A. flavus was inhibited by the broad-spectrum caspase inhibitor Z-VAD-fmk and partially inhibited by the ROS scavenger l-proline, which suggests that FOH induces apoptosis in A. flavus via a mechanism involving metacaspase activation and ROS production.

  8. Aflatoxin Production of Species and Strains of the Aspergillus flavus Group Isolated from Field Crops

    PubMed Central

    Schroeder, H. W.; Boller, R. A.

    1973-01-01

    Peanuts, cottonseed, rice, and sorghum from Texas were sampled over a 3-year period. To insure adequate isolation of alfatoxin-producing species of fungi, low-quality lots were sampled at a rate greater than their respective proportional representation. Aflatoxins were found each year in peanut and cottonseed and were found in 2 of 3 years in rice and sorghum. Aflatoxins were detected in all four crops. The Aspergillus flavus group was much more prevalent in peanut and rice than in cottonseed and sorghum. Of the isolates of the A. flavus group, 96% from peanuts, 79% from cottonseed, 49% from sorghum, and 35% from rice produced aflatoxins. The average toxin production of isolates from rice was much less than that from peanuts, cottonseed, or sorghum. More than 90% of all isolates of the A. flavus group were identified as the species A. flavus. A. parasiticus was isolated from all four crops. Only A. parasiticus produced aflatoxin G. PMID:4197766

  9. Detection of aflatoxigenic aspergillus flavus contamination of coconut (cocos nucifera) nutmeat (copra) using ammonia treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For many crops government regulations define mycotoxin contamination levels that represent the primary determinants of quality, value and possible uses of crops. Quality can be raised in some crops by lowering the mycotoxin level through removal of infected products. In the case of copra, the drie...

  10. Visualization of aflatoxigenic Aspergillus flavus contamination of coconut (Cocos nucifera) nutmeat (Copra) using ammonia treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For many crops government regulations define mycotoxin contamination levels that reflect the primary determinants of quality, value and possible uses of crops. Quality can be raised by lowering the mycotoxin level through a remediation process. In the case of copra, the dried nutmeat of the coconu...

  11. Seed-Derived Ethylene Facilitates Colonization but Not Aflatoxin Production by Aspergillus flavus in Maize

    PubMed Central

    Wang, Shi; Park, Yong-Soon; Yang, Yang; Borrego, Eli J.; Isakeit, Tom; Gao, Xiquan; Kolomiets, Michael V.

    2017-01-01

    Ethylene (ET) emitted by plant tissues has been broadly reported to play important roles in plant development, response to environmental stresses and defense against certain pathogens. Recent evidence obtained from using in vitro fungal cultures exposed to ET suggested that exogenous ET may regulate the production of aflatoxin by Aspergilli. However, the function of endogenous, seed-derived ET has not been explored. In this study, we found that the maize lipoxygenase lox3 mutant, previously reported to be susceptible to Aspergillus spp., emitted greater levels of ET upon A. flavus infection, suggesting the potential involvement of endogenous ET in the susceptibility of maize to A. flavus. Supporting this idea, both colonization and conidiation of A. flavus were reduced in wild-type (WT) kernels treated with AgNO3, an ET synthesis inhibitor. There was no ET emission from non-viable kernels colonized by A. flavus, suggesting that living seed but not the fungus itself was the primary source of ET released upon infection with A. flavus. The kernels of acs2 and acs6, two ET biosynthetic mutants carrying Mutator transposons in the ACC synthase genes, ACS2 and ACS6, respectively, displayed enhanced seed colonization and conidiation, but not the levels of aflatoxin, upon infection with A. flavus. Surprisingly, both acs2 and acs6 mutant kernels emitted greater levels of ET in response to infection by A. flavus as compared with WT seed. The increased ET in single mutants was found to be due to overexpression of functional ACS genes in response to A. flavus infection. Collectively, these findings suggested that ET emitted by infected seed facilitates colonization by A. flavus but not aflatoxin production.

  12. Functional Analysis of the Nitrogen Metabolite Repression Regulator Gene nmrA in Aspergillus flavus.

    PubMed

    Han, Xiaoyun; Qiu, Mengguang; Wang, Bin; Yin, Wen-Bing; Nie, Xinyi; Qin, Qiuping; Ren, Silin; Yang, Kunlong; Zhang, Feng; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    In Aspergillus nidulans, the nitrogen metabolite repression (NMR) regulator NmrA plays a major role in regulating the activity of the GATA transcription factor AreA during nitrogen metabolism. However, the function of nmrA in A. flavus has not been previously studied. Here, we report the identification and functional analysis of nmrA in A. flavus. Our work showed that the amino acid sequences of NmrA are highly conserved among Aspergillus species and that A. flavus NmrA protein contains a canonical Rossmann fold motif. Deletion of nmrA slowed the growth of A. flavus but significantly increased conidiation and sclerotia production. Moreover, seed infection experiments indicated that nmrA is required for the invasive virulence of A. flavus. In addition, the ΔnmrA mutant showed increased sensitivity to rapamycin and methyl methanesulfonate, suggesting that nmrA could be responsive to target of rapamycin signaling and DNA damage. Furthermore, quantitative real-time reverse transcription polymerase chain reaction analysis suggested that nmrA might interact with other nitrogen regulatory and catabolic genes. Our study provides a better understanding of NMR and the nitrogen metabolism network in fungi.

  13. Functional Analysis of the Nitrogen Metabolite Repression Regulator Gene nmrA in Aspergillus flavus

    PubMed Central

    Han, Xiaoyun; Qiu, Mengguang; Wang, Bin; Yin, Wen-Bing; Nie, Xinyi; Qin, Qiuping; Ren, Silin; Yang, Kunlong; Zhang, Feng; Zhuang, Zhenhong; Wang, Shihua

    2016-01-01

    In Aspergillus nidulans, the nitrogen metabolite repression (NMR) regulator NmrA plays a major role in regulating the activity of the GATA transcription factor AreA during nitrogen metabolism. However, the function of nmrA in A. flavus has not been previously studied. Here, we report the identification and functional analysis of nmrA in A. flavus. Our work showed that the amino acid sequences of NmrA are highly conserved among Aspergillus species and that A. flavus NmrA protein contains a canonical Rossmann fold motif. Deletion of nmrA slowed the growth of A. flavus but significantly increased conidiation and sclerotia production. Moreover, seed infection experiments indicated that nmrA is required for the invasive virulence of A. flavus. In addition, the ΔnmrA mutant showed increased sensitivity to rapamycin and methyl methanesulfonate, suggesting that nmrA could be responsive to target of rapamycin signaling and DNA damage. Furthermore, quantitative real-time reverse transcription polymerase chain reaction analysis suggested that nmrA might interact with other nitrogen regulatory and catabolic genes. Our study provides a better understanding of NMR and the nitrogen metabolism network in fungi. PMID:27933036

  14. Application of loop-mediated isothermal amplification assays for direct identification of pure cultures of Aspergillus flavus, A. nomius, and A. caelatus and for their rapid detection in shelled Brazil nuts.

    PubMed

    Luo, Jie; Taniwaki, Marta H; Iamanaka, Beatriz T; Vogel, Rudi F; Niessen, Ludwig

    2014-02-17

    Brazil nuts have a high nutritional content and are a very important trade commodity for some Latin American countries. Aflatoxins are carcinogenic fungal secondary metabolites. In Brazil nuts they are produced predominantly by Aspergillus (A.) nomius and A. flavus. In the present study we applied and evaluated two sets of primers previously published for the specific detection of the two species using loop-mediated isothermal amplification (LAMP) technology. Moreover, a primer set specific for A. caelatus as a frequently occurring non-aflatoxigenic member of Aspergillus section Flavi in Brazil nuts was newly developed. LAMP assays were combined with a simplified DNA release method and used for rapid identification of pure cultures and rapid detection of A. nomius and A. flavus from samples of shelled Brazil nuts. An analysis of pure cultures of 68 isolates representing the major Aspergillus species occurring on Brazil nuts showed that the three LAMP assays had individual accuracies of 61.5%, 84.4%, and 93.3% for A. flavus, A. nomius, and A. caelatus, respectively when morphological identification was used as a reference. The detection limits for conidia added directly to the individual LAMP reactions were found to be 10⁵ conidia per reaction with the primer set ID9 for A. nomius and 10⁴ conidia per reaction with the primer set ID58 for A. flavus. Sensitivity was increased to 10¹ and 10² conidia per reaction for A. nomius and A. flavus, respectively, when sample preparation included a spore disruption step. The results of LAMP assays obtained during the analysis of 32 Brazil nut samples from different regions of Brazil and from different steps in the production process of the commodity were compared with results obtained from mycological analysis and aflatoxin analysis of corresponding samples. Compared with mycological analysis of the samples, the Negative Predictive Values of LAMP assays were 42.1% and 12.5% while the Positive Predictive Values were 61

  15. 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...

  16. Comparison of soil and corn kernel Aspergillus flavus populations: evidence for niche specialization.

    PubMed

    Sweany, Rebecca Ruth; Damann, Kenneth Eugene; Kaller, Michael Douglas

    2011-08-01

    Aspergillus flavus is considered a generalist-opportunistic pathogen, but studies are beginning to show that A. flavus populations have strains specific to various hosts. The research objective was to determine whether A. flavus soil populations consist of solely saprophytic strains and strains which can be facultatively parasitic on corn. A. flavus was isolated from both corn kernels and soil within 11 Louisiana fields. Sixteen vegetative compatibility groups (VCGs) were identified among 255 soil isolates. Only 6 of the 16 VCGs were identified in the 612 corn isolates and 88% of corn isolates were in two VCGs, whereas only 5% of soil isolates belonged to the same two VCGs. Isolates were characterized for aflatoxin B1 production and sclerotial size. A random subset of the isolates (99 from corn and 91 from soil) were further characterized for simple-sequence repeat (SSR) haplotype and mating type. SSR polymorphisms revealed 26 haplotypes in the corn isolates and 78 in the soil isolates, and only 1 haplotype was shared between soil and corn isolates. Corn and soil populations were highly significantly different for all variables. Differences between corn and soil populations indicate that some soil isolates are not found in corn and some isolates have become specialized to infect corn. Further understanding of A. flavus virulence is important for development of resistant hybrids and for better biological control against toxigenic A. flavus.

  17. Genome Sequence of Aspergillus flavus NRRL 3357, a Strain That Causes Aflatoxin Contamination of Food and Feed.

    PubMed

    Nierman, William C; Yu, Jiujiang; Fedorova-Abrams, Natalie D; Losada, Liliana; Cleveland, Thomas E; Bhatnagar, Deepak; Bennett, Joan W; Dean, Ralph; Payne, Gary A

    2015-04-16

    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 immunocompromised human patients. Here, we report the genome sequence of strain NRRL 3357.

  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. 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...

  20. 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...

  1. Unravelling the diversity of the cyclopiazonic acid family of mycotoxins in Aspergillus flavus by UHPLC Triple-TOF HRMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclopiazonic acid (a-cyclopiazonic acid, a-CPA) is an indole-hydrindane-tetramic acid neurotoxin produced by various fungal species, including the notorious food and feed contaminant Aspergillus flavus. Despite its discovery in A. flavus cultures, approximately 40 years ago, its contribution to the...

  2. 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, ...

  3. 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.

  4. Trailing or paradoxical growth of Aspergillus flavus exposed to caspofungin is independent of genotype.

    PubMed

    Hadrich, Inès; Neji, Sourour; Makni, Fattouma; Ayadi, Ali; Elloumi, Moez; Ranque, Stéphane

    2014-12-01

    There are limited data on in vitro susceptibility testing of echinocandins against Aspergillus species. The objective of this study was to describe the phenotypes of Aspergillus flavus observed on exposure to caspofungin in vitro and to test whether these phenotypes were associated with A. flavus genotypes. The caspofungin MICs of 37 A. flavus clinical isolates collected from 14 patients with invasive aspergillosis were determined using Etest assays. Caspofungin MICs ranged from 0.012 to 0.064 mg l(-1); the modal MIC was 0.023 mg l(-1) and the MIC₅₀ and MIC₉₀ were 0.032 and 0.064 mg l(-1), respectively. A clear end point was noted in 24 (65 %) isolates, whereas seven (19 %) displayed a trailing effect and six (16 %) showed paradoxical growth when exposed to caspofungin. In these A. flavus isolates, the absence of a significant population structure or genetic differentiation indicated that trailing or paradoxical growth phenotypes were independent of microsatellite genotype.

  5. Microsatellite typing of Aspergillus flavus in patients with various clinical presentations of aspergillosis.

    PubMed

    Hadrich, Inès; Neji, Sourour; Drira, Inès; Trabelsi, Houwaida; Mahfoud, Nedia; Ranque, Stéphane; Makni, Fattouma; Ayadi, Ali

    2013-08-01

    Aspergillus flavus is the second most important Aspergillus species associated with aspergillosis and the incidence of infections caused by it are increasing in the immunocompromised population. This species is of major epidemiological importance in regions with a dry and hot climate. Despite the growing clinical significance of A. flavus, data on its molecular epidemiology are scarce. This study was aimed at examining whether isolates from distinct genotypes were involved in distinct clinical forms of aspergillosis. Sixty-three clinical isolates of A. flavus recovered from 35 patients with various clinical presentations of aspergillosis were characterized by microsatellite typing. The highest discriminatory power for a single locus was obtained with the AFLA1 marker, which had 14 distinct alleles and a 0.903 D value. The combination of all six markers yielded 48 different genotypes with a 0.994 D value. There was a considerable genetic diversity in the isolates and patients with invasive aspergillosis were usually colonized by multiples genotypes. There was no evidence that a given genotype was associated with a particular clinical presentation of A. flavus aspergillosis. The occurrence of more than one genotype in clinical samples indicates that a patient may be infected by multiple genotypes and that any particular isolate from a clinical specimen may not necessarily be the one causing aspergillosis.

  6. Effects of citral on Aspergillus flavus spores by quasi-elastic light scattering and multiplex microanalysis techniques.

    PubMed

    Luo, Man; Jiang, Li-Ke; Huang, Yao-Xiong; Xiao, Ming; Li, Bo; Zou, Guo-Lin

    2004-04-01

    Citral refined from Litsea cubeba oil has been found to have a strong influence on fungi, especially Aspergillus flavus. Multiplex microanalysis and quasi-elastic light scattering techniques were applied to study the effects of citral on Aspergillus flavus spores from the levels of membrane, organelle and intracellular macromolecule. It was found that citral injured the wall and the membrane of A. flavus spore, resulting in decrease of its elasticity. After entering the cell, citral not only influenced the genetic expression of mitochondrion reduplication and its morphology, but also changed the aggregation of protein-like macromolecules. As a result, cells, organelles and macromolecules lost their normal structures and functions, eventually leading to the loss of germination ability of A. flavus spores. Since Litsea cubeba oil as food additive and antifungal agent is safe and less poisonous, it is important to elucidate the inhibitory mechanisms of Litsea cubeba oil on the germination ability of A. flavus spore.

  7. Characterization of Iranian nonaflatoxigenic strains of Aspergillus flavus based on microsatellite-primed PCR

    PubMed Central

    Houshyarfard, Mahmoud; Rouhani, Hamid; Falahati-Rastegar, Mahrokh; Malekzadeh-Shafaroudi, Saeid; Mahdikhani-Moghaddam, Esmat

    2015-01-01

    Out of fifty-two Iranian nonaflatoxigenic strains of Aspergillus flavus,collected from various substrates (soil and kernel) and sources (peanut, corn and pistachio), fifteen representatives were selected according to their different geographical origins (six provinces: Guilan and Golestan, Ardebil, Fars, Kerman and Semnan) and vegetative compatibility groups (VCGs, IR1 to IR15) for microsatellite-primed PCR analysis. Two inter-simple sequence repeat (ISSR) primers AFMPP and AFM13 were used to determine polymorphism and the relationship among strain isolates. A. flavus isolates were identified by their morphologies and their identities were confirmed by PCR amplification using the specific primer pair ITS1 and ITS4. The results revealed variations in the percentages of polymorphisms. In the ISSR analysis, primers AFMPP and AFM13 generated a total of 18 and 23 amplicons among the fungal strains, out of which 12 (66.7%) and 22 (95.7%) were polymorphic, respectively. Cluster analysis of the ISSR data was carried out using 1 D DNA gel image analysis. The two dendrograms obtained through these markers showed six different clusterings of testing nonaflatoxigenic A. flavus L strains, but we noticed that some clusters were different in some cases. The microsatellite-primed PCR data revealed that the Iranian nonaflatoxigenic isolates of A. flavus were not clustered according to their origins and sources. This study is the first to characterize Iranian nonaflatoxigenic isolates of A. flavus using ISSR markers. PMID:27843995

  8. The mechanism of antifungal action of essential oil from dill (Anethum graveolens L.) on Aspergillus flavus.

    PubMed

    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.

  9. 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

  10. Survival of Aspergillus flavus and Fusarium moniliforme in High-Moisture Corn Stored Under Modified Atmospheres

    PubMed Central

    Wilson, David M.; Huang, L. H.; Jay, Edward

    1975-01-01

    Freshly harvested high-moisture corn with 29.4% moisture and corn remoistened to 19.6% moisture were inoculated with Aspergillus flavus Link ex Fr. and stored for 4 weeks at about 27 C in air (0.03% CO2, 21% O2, and 78% N2) and three modified atmospheres: (i) 99.7% N2 and 0.3% O2; (ii) 61.7% CO2, 8.7% O2, and 29.6% N2; and (iii) 13.5% CO2, 0.5% O2, and 84.8% N2. Kernel infections by A. flavus, Fusarium moniliforme (Sheld.) Snyd. et Hans., and other fungi were monitored weekly. The modified-atmosphere treatments delayed deterioration by A. flavus and F. moniliforme, but their growth was not completely stopped. A. flavus survived better in the remoistened than in the freshly harvested corn. F. moniliforme survived in both. A. flavus and F. moniliforme were the dominant fungi in corn removed from the modified atmospheres and exposed to normal air for 1 week. PMID:811165

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

    PubMed

    Solorzano, Cesar D; Abbas, Hamed K; Zablotowicz, Robert M; Chang, Perng-Kuang; Jones, Walker A

    2014-01-01

    A nontoxigenic Aspergillus flavus strain, K49, is currently being tested as a biological control agent in corn fields in the Mississippi Delta. However, little is known about the overall genetic diversity of A. flavus from year to year in corn fields and specifically in Mississippi. Our objective was to assess the genetic variability of A. flavus isolates from different seasons, inoculum sources, and years, from a no-till corn field. Of the 175 A. flavus isolates examined, 74 and 97 had the typical norB-cypA type I (1.5 kb) and type II (1.0 kb) deletion patterns, respectively. Variability in the sequence of the omtA gene of the majority of the field isolates (n = 118) was compared to strain K49. High levels of haplotypic diversity (24 omtA haplotypes; Hd = 0.61 ± 0.04) were found. Among the 24 haplotypes, two were predominant, H1 (n = 71), which consists of mostly toxigenic isolates, and H49 (n = 18), which consists of mostly atoxigenic isolates including K49. Toxigenic isolates were prevalent (60%) in this natural population. Nonetheless, about 15% of the population likely shared the same ancestral origin with K49. This study provides valuable information on the diversity of A. flavus. This knowledge can be further used to develop additional biological control strains.

  12. 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...

  13. 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...

  14. Workflow to study genetic biodiversity of aflatoxigenic Aspergillus spp. in Georgia, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut seeds were sampled from the entire state of Georgia in 2014. More than 600 isolates of Aspergillus spp. were collected using modified-dichloran rose Bengal (MDRB) medium, 240 of those isolates were fingerprinted with 25 InDel markers within the aflatoxin-biosynthesis gene cluster (ABC). Clust...

  15. Spatial Relationships of Soil Texture and Crop Rotation to Aspergillus flavus Community Structure in South Texas.

    PubMed

    Jaime-Garcia, Ramon; Cotty, Peter J

    2006-06-01

    ABSTRACT Aspergillus flavus, the causal agent of aflatoxin contamination of cottonseed, is a natural inhabitant of soils. A. flavus can be divided into the S and L strains, of which the S-strain isolates, on average, produce greater quantities of aflatoxins than the L-strain isolates. Aflatoxin contamination can be severe in several crops in South Texas. The structure of A. flavus communities residing in soils of South Texas was determined from 326 soil samples collected from 152 fields located from the Rio Grande Valley in the south to Fort Bend County in the north from 2001 through 2003. Analysis of variance indicated significant differences in the incidence of A. flavus isolates belonging to the S strain (percent S) among regions. The Coastal Bend (30.7%) and Upper Coast (25.5%) regions had significantly higher percent S incidence than the Rio Grande Valley (4.8%). No significant differences in percent S among years were detected. The CFU per gram of soil were not significantly different among regions. Strain S incidence was positively correlated with clay content and negatively correlated with sand content. Fields cropped to cotton the previous year had a higher S-strain incidence, whereas fields cropped to corn had greater total quantities of A. flavus propagules. Maps of S-strain patterns show that the S strain constitutes >30% of the overall A. flavus community in the area extending from the central Coastal Bend region to the central Upper Coast region. The west Rio Grande Valley had the lowest S-strain incidence (<10%). Geographic variation in S-strain incidence may influence the distribution of aflatoxin contamination in South Texas.

  16. Rapid detection of Aspergillus flavus in rice using biofunctionalized carbon nanotube field effect transistors.

    PubMed

    Villamizar, Raquel A; Maroto, Alicia; Rius, F Xavier

    2011-01-01

    In the present study, we have used carbon nanotube field effect transistors (FET) that have been functionalized with protein G and IgG to detect Aspergillus flavus in contaminated milled rice. The adsorbed protein G on the carbon nanotubes walls enables the IgG anti-Aspergillus antibodies to be well oriented and therefore to display full antigen binding capacity for fungal antigens. A solution of Tween 20 and gelatine was used as an effective blocking agent to prevent the non-specific binding of the antibodies and other moulds and also to protect the transducer against the interferences present in the rice samples. Our FET devices were able to detect at least 10 μg/g of A. flavus in only 30 min. To evaluate the selectivity of our biosensors, Fusarium oxysporum and Penicillium chrysogenum were tested as potential competing moulds for A. flavus. We have proved that our devices are highly selective tools for detecting mycotoxigenic moulds at low concentrations in real samples.

  17. Effects of nitrogen metabolism on growth and aflatoxin biosynthesis in Aspergillus flavus.

    PubMed

    Wang, Bin; Han, Xiaoyun; Bai, Youhuang; Lin, Zhenguo; Qiu, Mengguang; Nie, Xinyi; Wang, Sen; Zhang, Feng; Zhuang, Zhenhong; Yuan, Jun; Wang, Shihua

    2017-02-15

    Aflatoxins (AFs), produced mainly by Aspergillus flavus and Aspergillus parasiticus, are strongly toxic and carcinogenic. Here, we showed that glutamine is the optimal nitrogen source for AF-production in A. flavus grown in Czapek Dox medium. Additionally, 4mM glutamine was the threshold for high production of aflatoxin B1. However, no significant impact of glutamine synthetase inhibitor was detected for on AF biosynthesis. In contrast, rapamycin could significantly suppress the glutamine inducing effect on AFs production, simultaneously inhibiting the fungal growth and conidiation. To identify the genes and regulatory networks involved in AFs biosynthesis, especially concerning the nitrogen source metabolism pathway and the target of rapamycin (TOR) signaling pathway, we obtained transcriptomes for A. flavus under treatment of three nitrogen sources by RNA-sequencing. We identified 1429 differentially expressed genes. Through GO and KEGG pathway analyses, the relationship between nitrogen metabolism and AFs biosynthesis was revealed, and the effects of TOR inhibitor were confirmed. Additionally, the quantitative real-time PCR results verified the credibility and reliability of the RNA-seq data, and were consistent with the other experimental results. Our research laid the foundation for a primary study on the involvement of the nitrogen regulatory network and TOR signaling pathway in AF biosynthesis.

  18. 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.

  19. 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

  20. Sequence breakpoints in the aflatoxin biosynthesis gene cluster and flanking regions in nonaflatoxigenic Aspergillus flavus isolates.

    PubMed

    Chang, Perng-Kuang; Horn, Bruce W; Dorner, Joe W

    2005-11-01

    Aspergillus flavus populations are genetically diverse. Isolates that produce either, neither, or both aflatoxins and cyclopiazonic acid (CPA) are present in the field. We investigated defects in the aflatoxin gene cluster in 38 nonaflatoxigenic A. flavus isolates collected from southern United States. PCR assays using aflatoxin-gene-specific primers grouped these isolates into eight (A-H) deletion patterns. Patterns C, E, G, and H, which contain 40 kb deletions, were examined for their sequence breakpoints. Pattern C has one breakpoint in the cypA 3' untranslated region (UTR) and another in the verA coding region. Pattern E has a breakpoint in the amdA coding region and another in the ver1 5'UTR. Pattern G contains a deletion identical to the one found in pattern C and has another deletion that extends from the cypA coding region to one end of the chromosome as suggested by the presence of telomeric sequence repeats, CCCTAATGTTGA. Pattern H has a deletion of the entire aflatoxin gene cluster from the hexA coding region in the sugar utilization gene cluster to the telomeric region. Thus, deletions in the aflatoxin gene cluster among A. flavus isolates are not rare, and the patterns appear to be diverse. Genetic drift may be a driving force that is responsible for the loss of the entire aflatoxin gene cluster in nonaflatoxigenic A. flavus isolates when aflatoxins have lost their adaptive value in nature.

  1. 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.

  2. 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

  3. Aspergillus flavus dose-response curves to selected natural and synthetic antimicrobials.

    PubMed

    López-Malo, Aurelio; Alzamora, Stella M; Palou, Enrique

    2002-03-01

    The effects of selected concentrations of antimicrobials from natural (vanillin, thymol, eugenol, carvacrol or citral) or synthetic (potassium sorbate or sodium benzoate) origin on Aspergillus flavus lag time inoculated in laboratory media formulated at water activity (a(w)) 0.99 and pH 4.5 or 3.5, were evaluated. Time to detect a colony with a diameter > 0.5 mm was determined. Mold response was modeled using the Fermi function. Antimicrobial minimal inhibitory concentration (MIC) was defined as the minimal required inhibiting mold growth for 2 months. Fermi function successfully captured A. flavus dose-response curves to the tested antimicrobials with a highly satisfactory fit. Fermi equation coefficients, Pc and k, were used to compare antimicrobials and assess the effect of pH. Important differences in Pc and k were observed among antimicrobials, being natural antimicrobials less pH dependent than synthetic antimicrobials. A large Pc value represents a small antimicrobial effect on A. flavus lag time; thus, high concentrations are needed to delay growth. A. flavus exhibited higher sensitivity to thymol, eugenol, carvacrol, potassium sorbate (at pH 3.5), and sodium benzoate (at pH 3.5) than to vanillin or citral. MICs varied from 200 ppm of sodium bcnzoate at pH 3.5 to 1800 ppm of citral at both evaluated pHs.

  4. 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

  5. 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.

  6. Aspergillus flavus infection induces transcriptional and physical changes in developing maize kernels

    PubMed Central

    Dolezal, Andrea L.; Shu, Xiaomei; OBrian, Gregory R.; Nielsen, Dahlia M.; Woloshuk, Charles P.; Boston, Rebecca S.; Payne, Gary A.

    2014-01-01

    Maize kernels are susceptible to infection by the opportunistic pathogen Aspergillus flavus. Infection results in reduction of grain quality and contamination of kernels with the highly carcinogenic mycotoxin, aflatoxin. To understanding host response to infection by the fungus, transcription of approximately 9000 maize genes were monitored during the host-pathogen interaction with a custom designed Affymetrix GeneChip® DNA array. More than 4000 maize genes were found differentially expressed at a FDR of 0.05. This included the up regulation of defense related genes and signaling pathways. Transcriptional changes also were observed in primary metabolism genes. Starch biosynthetic genes were down regulated during infection, while genes encoding maize hydrolytic enzymes, presumably involved in the degradation of host reserves, were up regulated. These data indicate that infection of the maize kernel by A. flavus induced metabolic changes in the kernel, including the production of a defense response, as well as a disruption in kernel development. PMID:25132833

  7. 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....

  8. Controlling Aspergillus flavus and Aspergillus parasiticus growth and aflatoxin production in poultry feed using carvacrol and trans-cinnamaldehyde.

    PubMed

    Yin, Hsin-Bai; Chen, Chi-Hung; Kollanoor-Johny, Anup; Darre, Michael J; Venkitanarayanan, Kumar

    2015-09-01

    Aflatoxins (AF) are toxic metabolites primarily produced by molds, Aspergillus flavus and Aspergillus parasiticus. Contamination of poultry feed with AF is a major concern to the poultry industry due to severe economic losses stemming from poor performance, reduced egg production, and diminished egg hatchability. This study investigated the inhibitory effect of 2 generally regarded as safe (GRAS), natural plant compounds, namely carvacrol (CR) and trans-cinnamaldehyde (TC), on A. flavus and A. parasiticus growth and AF production in potato dextrose broth (PDB) and in poultry feed. In broth culture, PDB supplemented with CR (0%, 0.02%, 0.04% and 0.08%) or TC (0%, 0.005%, 0.01% and 0.02%) was inoculated with A. flavus or A. parasiticus (6 log CFU/mL), and mold counts and AF production were determined on days 0, 1, 3, and 5. Similarly, 200 g portions of poultry feed supplemented with CR or TC (0%, 0.4%, 0.8%, and 1.0%) were inoculated with each mold, and their counts and AF concentrations in the feed were determined at 0, 1, 2, 3, 4, 8, and 12 weeks of storage. Moreover, the effect of CR and TC on the expression of AF synthesis genes in A. flavus and A. parasiticus (aflC, nor1, norA, and ver1) was determined using real-time quantitative PCR (RT-qPCR). All experiments had duplicate samples and were replicated 3 times. Results indicated that CR and TC reduced A. flavus and A. parasiticus growth and AF production in broth culture and chicken feed (P<0.05). All tested concentrations of CR and TC decreased AF production in broth culture and chicken feed by at least 60% when compared to controls (P<0.05). In addition, CR and TC down-regulated the expression of major genes associated with AF synthesis in the molds (P<0.05). Results suggest the potential use of CR and TC as feed additives to control AF contamination in poultry feed.

  9. Potential of essential oils for protection of grains contaminated by aflatoxin produced by Aspergillus flavus

    PubMed Central

    Esper, Renata H.; Gonçalez, Edlayne; Marques, Marcia O. M.; Felicio, Roberto C.; Felicio, Joana D.

    2014-01-01

    Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oils of Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) on the mycelial growth and aflatoxin B1 production by Aspergillus flavus have been studied previously in culture medium. The aim of this study was to evaluate aflatoxin B1 production by Aspergillus flavus in real food systems (corn and soybean) treated with Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) essential oils. Samples with 60 g of the grains were treated with different volumes of essential oils, 200, 100, 50, and 10 μL for oregano and 50, 30, 15, and 10 μL for mentrasto. Fungal growth was evaluated by disk diffusion method. Aflatoxin B1 production was evaluated inoculating suspensions of A. flavus containing 1.3 × 105 spores/mL in 60 g of grains (corn and soybeans) after adjusting the water activity at 0.94. Aflatoxin was quantified by photodensitometry. Fungal growth and aflatoxin production were inhibited by essential oils, but the mentrasto oil was more effective in soybeans than that of oregano. On the other hand, in corn samples, the oregano essential oil was more effective than that of mentrasto. Chemical compositions of the essential oils were also investigated. The GC/MS oils analysis showed that the main component of mentrasto essential oil is precocene I and of the main component of oregano essential oil is 4-terpineol. The results indicate that both essential oils can become an alternative for the control of aflatoxins in corn and soybeans. PMID:24926289

  10. Potential of essential oils for protection of grains contaminated by aflatoxin produced by Aspergillus flavus.

    PubMed

    Esper, Renata H; Gonçalez, Edlayne; Marques, Marcia O M; Felicio, Roberto C; Felicio, Joana D

    2014-01-01

    Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oils of Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) on the mycelial growth and aflatoxin B1 production by Aspergillus flavus have been studied previously in culture medium. The aim of this study was to evaluate aflatoxin B1 production by Aspergillus flavus in real food systems (corn and soybean) treated with Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) essential oils. Samples with 60 g of the grains were treated with different volumes of essential oils, 200, 100, 50, and 10 μL for oregano and 50, 30, 15, and 10 μL for mentrasto. Fungal growth was evaluated by disk diffusion method. Aflatoxin B1 production was evaluated inoculating suspensions of A. flavus containing 1.3 × 10(5) spores/mL in 60 g of grains (corn and soybeans) after adjusting the water activity at 0.94. Aflatoxin was quantified by photodensitometry. Fungal growth and aflatoxin production were inhibited by essential oils, but the mentrasto oil was more effective in soybeans than that of oregano. On the other hand, in corn samples, the oregano essential oil was more effective than that of mentrasto. Chemical compositions of the essential oils were also investigated. The GC/MS oils analysis showed that the main component of mentrasto essential oil is precocene I and of the main component of oregano essential oil is 4-terpineol. The results indicate that both essential oils can become an alternative for the control of aflatoxins in corn and soybeans.

  11. An opportunistic human pathogen on the fly: strains of Aspergillus flavus vary in virulence in Drosophila melanogaster.

    PubMed

    Ramírez-Camejo, Luis A; Torres-Ocampo, Ana P; Agosto-Rivera, José L; Bayman, Paul

    2014-02-01

    Aspergilloses are fungal diseases in humans and animals that is caused by members of the genus Aspergillus. Aspergillus flavus is an important opportunistic pathogen, second only to A. fumigatus as a cause of human aspergillosis. Differences in virulence among A. flavus isolates from clinical and other substrates and mating types are not well known. The fruit fly Drosophila melanogaster has become a model organism for investigating virulence of human pathogens due to similarities between its immune system and that of mammals. In this study we used D. melanogaster as a model host to compare virulence among A. flavus strains obtained from clinical sources as compared with other substrates, between isolates of different mating types, and between isolates of A. flavus and A. fumigatus. Anesthetized flies were infected with A. flavus; mortality ranged from 15% to >90%. All strains were virulent, but some were significantly more so than others, which in turn led to the wide mortality range. Clinical strains were significantly less virulent than environmental strains, probably because the clinical strains were from culture collections and the environmental strains were recent isolates. Mean virulence did not differ between MAT1-1 and MAT1-2 mating types and the phylogeny of A. flavus isolates did not predict virulence. A. flavus was on average significantly more virulent than A. fumigatus on two lines of wild-type flies, Canton-S and Oregon-R. D. melanogaster is an attractive model to test pathogenicity and could be useful for identifying genes involved in virulence.

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

    PubMed

    Sobolev, Victor S; Krausert, Nicole M; Gloer, James B

    2016-01-27

    Two new stilbene derivatives have been isolated from peanut seeds challenged by an Aspergillus flavus strain, along with chiricanine B, which has not been previously reported from peanuts, as well as a stilbenoid reported previously only as a synthetic product. The structures of these new putative phytoalexins were determined by analysis of (1)H and (13)C NMR, HRESIMS, MS(n), and UV data. The new stilbenoids were named arahypin-13 (21), arahypin-14 (22), and arahypin-15 (23). Together with other known bioactive peanut stilbenoids that were also produced in the challenged seeds, these new compounds may play a defensive role against invasive fungi.

  13. Unravelling the Diversity of the Cyclopiazonic Acid Family of Mycotoxins in Aspergillus flavus by UHPLC Triple-TOF HRMS

    PubMed Central

    Uka, Valdet; Moore, Geromy G.; Arroyo-Manzanares, Natalia; Nebija, Dashnor; De Saeger, Sarah; Diana Di Mavungu, José

    2017-01-01

    Cyclopiazonic acid (α-cyclopiazonic acid, α-CPA) is an indole-hydrindane-tetramic acid neurotoxin produced by various fungal species, including the notorious food and feed contaminant Aspergillus flavus. Despite its discovery in A. flavus cultures approximately 40 years ago, its contribution to the A. flavus mycotoxin burden is consistently minimized by our focus on the more potent carcinogenic aflatoxins also produced by this fungus. Here, we report the screening and identification of several CPA-type alkaloids not previously found in A. flavus cultures. Our identifications of these CPA-type alkaloids are based on a dereplication strategy involving accurate mass high resolution mass spectrometry data and a careful study of the α-CPA fragmentation pattern. In total, 22 CPA-type alkaloids were identified in extracts from the A. flavus strains examined. Of these metabolites, 13 have been previously reported in other fungi, though this is the first report of their existence in A. flavus. Two of our metabolite discoveries, 11,12-dehydro α-CPA and 3-hydroxy-2-oxo CPA, have never been reported for any organism. The conspicuous presence of CPA and its numerous derivatives in A. flavus cultures raises concerns about the long-term and cumulative toxicological effects of these fungal secondary metabolites and their contributions to the entire A. flavus mycotoxin problem. PMID:28098779

  14. Production, purification and characterization of an extracellular alpha-amylase enzyme isolated from Aspergillus flavus.

    PubMed

    Abou-Zeid, A M

    1997-01-01

    Filamentous fungi isolated from cereals were screened for their ability to produce alpha-amylase (1,4-alpha-glucan glucanohydrolase, EC 3.2.1.1). A selected strain identified as Aspergillus flavus showed high enzymatic activity. A single extracellular alpha-amylase was purified to homogeneity by a starch adsorption method. The molecular weight (M(r)) of the A. flavus alpha-amylase was approximately 75,000 +/- 3,000 by polyacrylamide gel electrophoresis (PAGE) and that of the subunit was approximately 75,000 +/- 3000 SDS-PAGE. The optimal activity of the purified enzyme was achieved at pH 7.0 and 30 degrees C. K+ ions increased the alpha-amylase activity, but Mg2+ did not greatly affect enzyme activity. Mn2+, Zn2+, Cu2+ and Fe3+ ions strongly inhibited the enzyme activity. The products of hydrolysis of native starch by the A. flavus enzyme were mainly glucose as well as unidentified oligosaccharides.

  15. Adenylate Cyclase AcyA Regulates Development, Aflatoxin Biosynthesis and Fungal Virulence in Aspergillus flavus

    PubMed Central

    Yang, Kunlong; Qin, Qiuping; Liu, Yinghang; Zhang, Limei; Liang, Linlin; Lan, Huahui; Chen, Chihao; You, Yunchao; Zhang, Feng; Wang, Shihua

    2016-01-01

    Aspergillus flavus is one of the most important opportunistic pathogens of crops and animals. The carcinogenic mycotoxin, aflatoxins produced by this pathogen cause a health problem to human and animals. Since cyclic AMP signaling controls a range of physiological processes, like fungal development and infection when responding to extracellular stimuli in fungal pathogens, in this study, we investigated the function of adenylate cyclase, a core component of cAMP signaling, in aflatoxins biosynthesis and virulence on plant seeds in A. flavus. A gene replacement strategy was used to generate the deletion mutant of acyA that encodes the adenylate cyclase. Severe defects in fungal growth, sporulation and sclerotia formation were observed in the acyA deletion mutant. The defect in radical growth could be partially rescued by exogenous cAMP analog. The acyA mutant was also significantly reduced in aflatoxins production and virulence. Similar to the former studies in other fungi, The acyA mutant showed enhancing tolerance to oxidative stress, but more sensitive to heat stress. Overall, the pleiotropic defects of the acyA deletion mutant indicates that the cAMP-PKA pathway is involved in fungal development, aflatoxins biosynthesis and plant seed invasion in A. flavus. PMID:28066725

  16. Antifungal properties and inhibitory effects upon aflatoxin production of Thymus vulgaris L. by Aspergillus flavus Link.

    PubMed

    Kohiyama, Cássia Yumie; Yamamoto Ribeiro, Milene Mayumi; Mossini, Simone Aparecida Galerani; Bando, Erika; Bomfim, Natália da Silva; Nerilo, Samuel Botião; Rocha, Gustavo Henrique Oliveira; Grespan, Renata; Mikcha, Jane Martha Graton; Machinski, Miguel

    2015-04-15

    The antifungal and antiaflatoxigenic properties of Thymus vulgaris essential oil (TEO) were evaluated upon Aspergillus flavus "in vitro". Suspension containing 10(6) of A. flavus were cultivated with TEO in concentrations ranging from 50 to 500 μg/mL. TEO reached minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 250 μg/mL. Inhibition of ergosterol biosynthesis was detected at a concentration of 100 μg/mL of TEO. Morphological evaluation performed by both light microscopy and scanning electron microscopy showed that antifungal activity of TEO could be detected starting at a concentration of 50 μg/mL and the fungicide effect at a concentration of 250 μg/mL. TEO completely inhibited production of both B1 and B2 aflatoxins (AFB1 and AFB2) at a concentration of 150 μg/mL. This way, fungal biomass development and aflatoxin production were dependent on TEO concentration. Therefore, TEO was capable of controlling the growth of A. flavus and its production of aflatoxins.

  17. Using Predictions Based on Geostatistics to Monitor Trends in Aspergillus flavus Strain Composition.

    PubMed

    Orum, T V; Bigelow, D M; Cotty, P J; Nelson, M R

    1999-09-01

    ABSTRACT Aspergillus flavus is a soil-inhabiting fungus that frequently produces aflatoxins, potent carcinogens, in cottonseed and other seed crops. A. flavus S strain isolates, characterized on the basis of sclerotial morphology, are highly toxigenic. Spatial and temporal characteristics of the percentage of the A. flavus isolates that are S strain (S strain incidence) were used to predict patterns across areas of more than 30 km(2). Spatial autocorrelation in S strain incidence in Yuma County, AZ, was shown to extend beyond field boundaries to adjacent fields. Variograms revealed both short-range (2 to 6 km) and long-range (20 to 30 km) spatial structure in S strain incidence. S strain incidence at 36 locations sampled in July 1997 was predicted with a high correlation between expected and observed values (R = 0.85, P = 0.0001) by kriging data from July 1995 and July 1996. S strain incidence at locations sampled in October 1997 and March 1998 was markedly less than predicted by kriging data from the same months in prior years. Temporal analysis of four locations repeatedly sampled from April 1995 through July 1998 also indicated a major reduction in S strain incidence in the Texas Hill area after July 1997. Surface maps generated by kriging point data indicated a similarity in the spatial pattern of S strain incidence among all sampling dates despite temporal changes in the overall S strain incidence. Geostatistics provided useful descriptions of variability in S strain incidence over space and time.

  18. Antifungal activity of a liposomal itraconazole formulation in experimental Aspergillus flavus keratitis with endophthalmitis.

    PubMed

    Leal, André Ferraz Goiana; Leite, Melyna Chaves; Medeiros, Caroline Sanuzi Quirino; Cavalcanti, Isabella Macário Ferro; Wanderley, Almir Gonçalves; Magalhães, Nereide Stela Santos; Neves, Rejane Pereira

    2015-04-01

    The aim of this study was to assess the efficacy of topical application of a liposomal formulation of itraconazole for the treatment of experimental keratitis with endophthalmitis caused by Aspergillus flavus. The liposomes were obtained by the lipid film hydration method followed by sonication. Adult female Wistar rats (weighing 200-220 g) were immunosuppressed by intraperitoneal injection of 150 mg/kg of cyclophosphamide 3 days before infection by exposure to the fungus A. flavus (10(7) spores/ml). Forty-eight hours later, the animals were treated with the liposomal formulation. For comparison, one group of animals (n = 6) was treated with the same drug not encapsulated. At the end of the experiment, the animals were evaluated for clinical signs and number of colony forming units (CFU/g), along with direct microscopic examination. The results indicated that the liposomal formulation of itraconazole has better antifungal activity than the unencapsulated drug in the treatment of fungal keratitis with endophthalmitis caused experimentally by A. flavus in Wistar rats.

  19. Oxidative stress and carbon metabolism influence Aspergillus flavus transcriptome composition and secondary metabolite production

    PubMed Central

    Fountain, Jake C.; Bajaj, Prasad; Pandey, Manish; Nayak, Spurthi N.; Yang, Liming; Kumar, Vinay; Jayale, Ashwin S.; Chitikineni, Anu; Zhuang, Weijian; Scully, Brian T.; Lee, R. Dewey; Kemerait, Robert C.; Varshney, Rajeev K.; Guo, Baozhu

    2016-01-01

    Contamination of crops with aflatoxin is a serious global threat to food safety. Aflatoxin production by Aspergillus flavus is exacerbated by drought stress in the field and by oxidative stress in vitro. We examined transcriptomes of three toxigenic and three atoxigenic isolates of A. flavus in aflatoxin conducive and non-conducive media with varying levels of H2O2 to investigate the relationship of secondary metabolite production, carbon source, and oxidative stress. We found that toxigenic and atoxigenic isolates employ distinct mechanisms to remediate oxidative damage, and that carbon source affected the isolates’ expression profiles. Iron metabolism, monooxygenases, and secondary metabolism appeared to participate in isolate oxidative responses. The results suggest that aflatoxin and aflatrem biosynthesis may remediate oxidative stress by consuming excess oxygen and that kojic acid production may limit iron-mediated, non-enzymatic generation of reactive oxygen species. Together, secondary metabolite production may enhance A. flavus stress tolerance, and may be reduced by enhancing host plant tissue antioxidant capacity though genetic improvement by breeding selection. PMID:27941917

  20. Lactobacillus casei CRL 431 and Lactobacillus rhamnosus CRL 1224 as biological controls for Aspergillus flavus strains.

    PubMed

    Bueno, Dante J; Silva, Julio O; Oliver, Guillermo; González, Silvia N

    2006-10-01

    The effect of two species of lactobacilli, Lactobacillus casei CRL 431 and Lactobacillus rhamnosus CRL 1224, on growth of different Aspergillus flavus strains was determined. A. flavus strains (Ap, TR2, or CF80) were grown in LAPTg broth at 37 degrees C for 7 days as a single culture and in association with L. casei CRL 431 or L. rhamnosus CRL 1224 at initial inoculum ratios of 1:1, 1:10, and 1:100. In most cases, the mixed cultures had a lower fungal growth and a lower pH than the control cultures. Mycelial dry weight was reduced to 73 and 85% using L. casei CRL 431 and L. rhamnosus CRL 1224, respectively. The pH decrease in mixed cultures when the fungal mycelial dry weight is reduced may play an important role in inhibition. The number of viable bacteria was variably affected by fungal growth. These results indicate that L. casei CRL 431 and L. rhamnosus CRL 1224 may be useful as potential biocontrol agent against A. flavus.

  1. Heterologous, Expression, and Characterization of Thermostable Glucoamylase Derived from Aspergillus flavus NSH9 in Pichia pastoris

    PubMed Central

    Karim, Kazi Muhammad Rezaul; Hossain, Md. Anowar; Sing, Ngieng Ngui; Mohd Sinang, Fazia; Hussain, Mohd Hasnain Md.; Roslan, Hairul Azman

    2016-01-01

    A novel thermostable glucoamylase cDNA without starch binding domain (SBD) of Aspergillus flavus NSH9 was successfully identified, isolated, and overexpressed in Pichia pastoris GS115. The complete open reading frame of glucoamylase from Aspergillus flavus NSH9 was identified by employing PCR that encodes 493 amino acids lacking in the SBD. The first 17 amino acids were presumed to be a signal peptide. The cDNA was cloned into Pichia pastoris and the highest expression of recombinant glucoamylase (rGA) was observed after 8 days of incubation period with 1% methanol. The molecular weight of the purified rGA was about 78 kDa and exhibited optimum catalytic activity at pH 5.0 and temperature of 70°C. The enzyme was stable at higher temperature with 50% of residual activity observed after 20 min at 90°C and 100°C. Low concentration of metal (Mg++, Fe++, Zn++, Cu++, and Pb++) had positive effect on rGA activity. This rGA has the potential for use and application in the saccharification steps, due to its thermostability, in the starch processing industries. PMID:27504454

  2. RmtA, a Putative Arginine Methyltransferase, Regulates Secondary Metabolism and Development in Aspergillus flavus

    PubMed Central

    Satterlee, Timothy; Cary, Jeffrey W.; Calvo, Ana M.

    2016-01-01

    Aspergillus flavus colonizes numerous oil seed crops such as corn, peanuts, 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 described to be involved in epigenetics regulation through histone modification. Epigenetics regulation affects a variety of cellular processes, including morphogenesis and secondary metabolism. Our study shows that deletion of rmtA in A. flavus results in hyperconidiating colonies, indicating that rmtA is a repressor of asexual development in this fungus. The increase in conidiation in the absence of rmtA coincides with greater expression of brlA, abaA, and wetA compared to that in the wild type. Additionally, the rmtA deletion mutant presents a drastic reduction or loss of sclerotial production, while forced expression of this gene increased the ability of this fungus to generate these resistant structures, revealing rmtA as a positive regulator of sclerotial formation. Importantly, rmtA is also required for the production of aflatoxin B1 in A. flavus, affecting the expression of aflJ. Furthermore, biosynthesis of additional metabolites is also controlled by rmtA, indicating a broad regulatory output in the control of secondary metabolism. This study also revealed that rmtA positively regulates the expression of the global regulatory gene veA, which could contribute to mediate the effects of rmtA on development and secondary metabolism in this relevant opportunistic plant pathogen. PMID:27213959

  3. Aspergillus flavus induces granulomatous cerebral aspergillosis in mice with display of distinct cytokine profile.

    PubMed

    Anand, R; Shankar, J; Tiwary, B N; Singh, A P

    2015-04-01

    Aspergillus flavus is one of the leading Aspergillus spp. resulting in invasive aspergillosis of central nervous system (CNS) in human beings. Immunological status in aspergillosis of central nervous system remains elusive in case of both immunocompetent and immunocompromised patients. Since cytokines are the major mediators of host response, evaluation of disease pathology along with cytokine profile in brain may provide snapshots of neuro-immunological response. An intravenous model of A. flavus infection was utilized to determine the pathogenicity of infection and cytokine profile in the brain of male BALB/c mice. Enumeration of colony forming units and histopathological analyses were performed on the brain tissue at distinct time periods. The kinetics of cytokines (TNF-α, IFN-γ, IL-12/IL-23p40, IL-6, IL-23, IL-17A and IL-4) was evaluated at 6, 12, 24, 48, 72 and 96h post infection (hPI) in brain homogenates using murine cytokine specific enzyme linked immunosorbent assay. Histological analysis exhibited the hyphae with leukocyte infiltrations leading to formation of granulomata along with ischemia and pyknosis of neurons in the brain of infected mice. Diseased mice displayed increased secretion of IFN-γ, IL-12p40 and IL-6 with a concomitant reduction in the secretion of Th2 cytokine IL-4, and Th17 promoting cytokine, IL-23 during the late phase of infection. A.flavus induced inflammatory granulomatous cerebral aspergillosis in mice, characterized by a marked increase in the Th1 cytokines and neurons undergoing necrosis. A marked increase in necrosis of neurons with concurrent inflammatory responses might have led to the host mortality during late phase of infection.

  4. Effects of Gamma and Electron Beam Radiation on Brazil Nuts Artificially Inoculated with Aspergillus flavus.

    PubMed

    Assunção, Ednei; Reis, Tatiana Alves; Baquião, Arianne Costa; Corrêa, Benedito

    2015-07-01

    The aim of this study was to evaluate the effects of gamma radiation (GR) and electron beam (EB) on Brazil nut samples contaminated with Aspergillus flavus. Fifty samples were spread with an A. flavus suspension and incubated at 30°C and a relative humidity of 93%. After 15 days of incubation, mycobiota and aflatoxin analysis were performed. The samples were divided into three groups (control, group 1, and group 2) that received radiation doses of 0 kGy (control) and 5 and 10 kGy each of GR and EB (groups 1 and 2). Noninoculated samples were irradiated with the same doses for sensory evaluation. The results showed that after 15 days of incubation, the average water activity of the samples was 0.80. The irradiation with GR and EB at doses of 5 and 10 kGy was able to eliminate A. flavus in Brazil nut samples. Aflatoxin analysis showed that EB doses of 5 and 10 kGy reduced aflatoxin B1 levels by 53.32 and 65.66%, respectively, whereas the same doses of GR reduced the levels of this toxin by 70.61 and 84.15% compared with the level in the control groups. Sensory evaluation demonstrated that the texture and odor of irradiated Brazil nut samples were acceptable. The taste evaluation indicated that 5 kGy of GR was judged acceptable. The results highlight that both irradiation processes (5- and 10-kGy doses) showed efficiency in A. flavus and aflatoxin elimination. GR and EB treatments resulted in some alterations in the sensory attributes of samples with the doses used in this study; however, Brazil nut samples irradiated with 5-kGy GR doses were considered acceptable.

  5. Buckwheat achenes antioxidant profile modulates Aspergillus flavus growth and aflatoxin production.

    PubMed

    Chitarrini, G; Nobili, C; Pinzari, F; Antonini, A; De Rossi, P; Del Fiore, A; Procacci, S; Tolaini, V; Scala, V; Scarpari, M; Reverberi, M

    2014-10-17

    Buckwheat (Fagopyrum spp.) is a "pseudo-cereal" of great interest in the production of healthy foods since its flour, derived from achenes, is enriched with bioactive compounds and, due to the absence of gluten, may be used in composition of celiac diets. Amongst buckwheat species, F. tataricum achenes possess a larger amount of the antioxidant flavenol rutin than the common buckwheat F. esculentum. Ongoing climate change may favor plant susceptibility to the attack by pathogenic, often mycotoxigenic, fungi with consequent increase of mycotoxins in previously unexploited feeds and foodstuffs. In particular, Aspergillus flavus, under suitable environmental conditions such as those currently occurring in Italy, may produce aflatoxin B1 (AFB1), the most carcinogenic compound of fungal origin which is classified by IARC as Category 1. In this study, the viable achenes of two buckwheat species, F. tataricum (var. Golden) and F. esculentum (var. Aelita) were inoculated with an AFB1-producing A. flavus NRRL 3357 to analyze their relative performances against fungal invasion and toxin contamination. Notably, we sought the existence of a correlation between the amount of tocols/flavonols in the achenes of buckwheat, infected and non-infected with A. flavus, and to analyze the ability of the pathogen to grow and produce toxin during achene infection. Results suggest that achenes of F. tataricum, the best producer of antioxidant compounds in this study, are less susceptible to A. flavus infection and consequently, but not proportionally, to mycotoxin contamination compared with F. esculentum. Moreover, rutin-derived quercetin appears to be more efficient in inhibiting aflatoxin biosynthesis than the parent compound.

  6. Identification of two aflatrem biosynthesis gene loci in Aspergillus flavus and metabolic engineering of Penicillium paxilli to elucidate their function.

    PubMed

    Nicholson, Matthew J; Koulman, Albert; Monahan, Brendon J; Pritchard, Beth L; Payne, Gary A; Scott, Barry

    2009-12-01

    Aflatrem is a potent tremorgenic toxin produced by the soil fungus Aspergillus flavus, and a member of a structurally diverse group of fungal secondary metabolites known as indole-diterpenes. Gene clusters for indole-diterpene biosynthesis have recently been described in several species of filamentous fungi. A search of Aspergillus complete genome sequence data identified putative aflatrem gene clusters in the genomes of A. flavus and Aspergillus oryzae. In both species the genes for aflatrem biosynthesis cluster at two discrete loci; the first, ATM1, is telomere proximal on chromosome 5 and contains a cluster of three genes, atmG, atmC, and atmM, and the second, ATM2, is telomere distal on chromosome 7 and contains five genes, atmD, atmQ, atmB, atmA, and atmP. Reverse transcriptase PCR in A. flavus demonstrated that aflatrem biosynthesis transcript levels increased with the onset of aflatrem production. Transfer of atmP and atmQ into Penicillium paxilli paxP and paxQ deletion mutants, known to accumulate paxilline intermediates paspaline and 13-desoxypaxilline, respectively, showed that AtmP is a functional homolog of PaxP and that AtmQ utilizes 13-desoxypaxilline as a substrate to synthesize aflatrem pathway-specific intermediates, paspalicine and paspalinine. We propose a scheme for aflatrem biosynthesis in A. flavus based on these reconstitution experiments in P. paxilli and identification of putative intermediates in wild-type cultures of A. flavus.

  7. Gene expression profiling and identification of resistance genes to aspergillus flavus infection in peanut through EST and microarray strategies.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus and A. parasiticus infect peanut seeds and produce aflatoxins, which are associated with various diseases in domestic animals and humans throughout the world. The most cost-effective strategy to minimize aflatoxin contamination involves the development of peanut cultivars that are...

  8. Effects of laeA deletion on Aspergillus flavus conidial development and hydrophobicity may contribute to loss of aflatoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The laeA gene encodes a nuclear protein that governs production of multiple fungal secondary metabolites. We examined the effects of laeA deletion in an Aspergillus flavus strain. Compared to wild type, expression of genes involved in secondary metabolism, conidiation and hydrophobicity was drastica...

  9. Comparison of the side-needle and knife techniques for inducing Aspergillus flavus infection and aflatoxin accumulation in corn hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin in corn grain is a problem in many areas of the world. Any combination of environmentally stressful or agronomically unfavorable conditions can increase the likelihood of Aspergillus flavus infection and production of aflatoxin in the corn grain. In the absence of a consistent natural A....

  10. Evaluation of recycled bioplastic pellets and a sprayable formulation for application of an Aspergillus flavus biocontrol strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biocontrol of Aspergillus flavus using inoculated bioplastic granules has been proven to be effective under laboratory and field conditions. In the present study, the use of low-density pellets from recycled bioplastic as a biocontrol strain carrier was evaluated. Applying recycled bioplastic pell...

  11. Identification of maize genes associated with host plant resistance and susceptibility to Aspergillus flavus infection and aflatoxin accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus infection and aflatoxin contamination of maize pose negative impacts in agriculture and health. Commercial maize hybrids are generally susceptible to this fungus. Significant levels of host plant resistance have been observed in certain maize inbred lines. This study was conducted...

  12. Comparison of expression of secondary metabolite biosynthesis cluster genes in Aspergillus flavus, A. parasiticus, and A. oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 55 secondary metabolite biosynthesis gene clusters are predicted to be present in the Aspergillus flavus genome. In spite of this the biosynthesis of only a few metabolites, such as the aflatoxin, cyclopiazonic acid and aflatrem, has been correlated with a particular gene cluster. Using RN...

  13. Characterization of a maize association mapping panel for new sources of Aspergillus flavus and aflatoxin accumulation resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays L.) susceptibility to ear rot and aflatoxin accumulation by Aspergillus flavus (Link:Fr) causes significant economic and human health damage worldwide. Although host plant resistance is an ideal solution to the problem, no commercial varieties display sufficient levels of resistance ...

  14. Evaluation of the expression genes associated with resistance to Aspergillus flavus colonization and aflatoxin production in different maize lines.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are carcinogenic toxic compounds produced by Aspergillus flavus during infection of crops including maize (Zea mays L.). Contamination of maize with aflatoxin is exacerbated by late season drought stress. Previous studies have implicated numerous resistance-associated proteins (RAPs) that...

  15. Community structure of Aspergillus flavus and A. parasiticus in major almond producing areas of California, United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several nut crops including almonds, pistachios, and walnuts can become contaminated with mycotoxins. Of greatest economic significance are aflatoxins, which are mainly produced by members of Aspergillus section Flavi. The distribution of the two sclerotial-size morphotypes of A. flavus (i.e. S and ...

  16. Aspergillus flavus growth and aflatoxin production as influenced by total lipid content during growth and development of cottonseed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus infects several food and feed crops such as corn, cotton, peanuts and tree nut crops and contaminates the seed with carcinogenic aflatoxins. These susceptible crops contain rich reserves of lipids and fatty acids. The nature of relationship between lipids and the ability of the f...

  17. Inhibition of Aspergillus flavus on agar media and brown rice cereal bars using cold atmospheric plasma treatment.

    PubMed

    Suhem, Kitiya; Matan, Narumol; Nisoa, Mudtorlep; Matan, Nirundorn

    2013-02-01

    This study aimed to optimize the operating parameters of cold atmospheric plasma treatment to inhibit the growth of Aspergillus flavus on agar media and brown rice cereal bars. The effects of argon plasma jet treatment on the growth of A. flavus on malt extract agar (MEA) at powers of 20 W and 40 W with exposure times at 5, 15 and 25 min were studied using response surface methodology (RSM) with a central composite face-centered (CCF) design. Multiple regression analysis indicated that plasma treatment at 40 W for 25 min is most effective for inhibiting growth of A. flavus on the agar medium. On brown rice cereal bars, plasma powered at 40 W for 20 min was capable of giving protection against A. flavus growth for up to 20 days under storage conditions of 25°C and 100% RH. These results demonstrated the potential of cold atmospheric plasma jet treatment to control mold growth on various food products.

  18. Menadione-Induced Oxidative Stress Re-Shapes the Oxylipin Profile of Aspergillus flavus and Its Lifestyle

    PubMed Central

    Zaccaria, Marco; Ludovici, Matteo; Sanzani, Simona Marianna; Ippolito, Antonio; Aiese Cigliano, Riccardo; Sanseverino, Walter; Scarpari, Marzia; Scala, Valeria; Fanelli, Corrado; Reverberi, Massimo

    2015-01-01

    Aspergillus flavus is an efficient producer of mycotoxins, particularly aflatoxin B1, probably the most hepatocarcinogenic naturally-occurring compound. Although the inducing agents of toxin synthesis are not unanimously identified, there is evidence that oxidative stress is one of the main actors in play. In our study, we use menadione, a quinone extensively implemented in studies on ROS response in animal cells, for causing stress to A. flavus. For uncovering the molecular determinants that drive A. flavus in challenging oxidative stress conditions, we have evaluated a wide spectrum of several different parameters, ranging from metabolic (ROS and oxylipin profile) to transcriptional analysis (RNA-seq). There emerges a scenario in which A. flavus activates several metabolic processes under oxidative stress conditions for limiting the ROS-associated detrimental effects, as well as for triggering adaptive and escape strategies. PMID:26512693

  19. Larval Preference and Performance of Amyelois transitella (Navel Orangeworm, Lepidoptera: Pyralidae) in Relation to the Fungus Aspergillus flavus.

    PubMed

    Ampt, Eline A; Bush, Daniel S; Siegel, Joel P; Berenbaum, May R

    2016-02-01

    The navel orangeworm, Amyelois transitella (Walker), is a polyphagous pest of California nut crops and is responsible for extensive losses in the United States. It directly damages crops by feeding and contaminating nuts with frass and webbing and vectors saprophytic fungi that infect crops. The navel orangeworm is commonly associated with Aspergillus species, including the toxigenic Aspergillus flavus, which causes crop loss by producing carcinogens, including aflatoxin B1. This lepidopteran-fungus association is the most economically serious pest complex in Central Valley orchards, and evidence indicates that this relationship is mutualistic. We assessed preference and performance of navel orangeworm larvae associated with A. flavus in behavioral bioassays in which neonates were allowed to orient within arenas to media with or without fungal tissue, and performance bioassays in which larvae were reared with and without A. flavus on potato dextrose agar (PDA) and a semidefined almond PDA diet to evaluate effects on development and pupal weight. Navel orangeworm larvae were attracted to A. flavus and developed faster in its presence, indicating a nutritional benefit to the caterpillars. Larvae reached pupation ∼33% faster on diet containing A. flavus, and pupal weights were ∼18% higher for males and ∼13% higher for females on this diet. Our findings indicate that A. flavus plays an important role in larval orientation and development on infected hosts. The preference-performance relationship between navel orangeworms and Aspergillus flavus is consistent with a facultative mutualism that has broad implications for pest management efforts and basic understanding of Lepidoptera-plant interactions.

  20. The inhibitory effects of Curcuma longa L. essential oil and curcumin on Aspergillus flavus link growth and morphology.

    PubMed

    Dias Ferreira, Flávio; Mossini, Simone Aparecida Galerani; Dias Ferreira, Francine Maery; Arrotéia, Carla Cristina; da Costa, Christiane Luciana; Nakamura, Celso Vataru; Machinski, Miguel

    2013-01-01

    The essential oil from Curcuma longa L. was analysed by GC/MS. The major components of the oil were ar-turmerone (33.2%), α -turmerone (23.5%) and β -turmerone (22.7%). The antifungal activities of the oil were studied with regard to Aspergillus flavus growth inhibition and altered morphology, as preliminary studies indicated that the essential oil from C. longa inhibited Aspergillus flavus Link aflatoxin production. The concentration of essential oil in the culture media ranged from 0.01% to 5.0% v/v, and the concentration of curcumin was 0.01-0.5% v/v. The effects on sporulation, spore viability, and fungal morphology were determined. The essential oil exhibited stronger antifungal activity than curcumin on A. flavus. The essential oil reduced the fungal growth in a concentration-dependent manner. A. flavus growth rate was reduced by C. longa essential oil at 0.10%, and this inhibition effect was more efficient in concentrations above 0.50%. Germination and sporulation were 100% inhibited in 0.5% oil. Scanning electron microscopy (SEM) of A. flavus exposed to oil showed damage to hyphae membranes and conidiophores. Because the fungus is a plant pathogen and aflatoxin producer, C. longa essential oil may be used in the management of host plants.

  1. The Inhibitory Effects of Curcuma longa L. Essential Oil and Curcumin on Aspergillus flavus Link Growth and Morphology

    PubMed Central

    Mossini, Simone Aparecida Galerani; Ferreira, Francine Maery Dias; Arrotéia, Carla Cristina; da Costa, Christiane Luciana; Nakamura, Celso Vataru; Machinski Junior, Miguel

    2013-01-01

    The essential oil from Curcuma longa L. was analysed by GC/MS. The major components of the oil were ar-turmerone (33.2%), α-turmerone (23.5%) and β-turmerone (22.7%). The antifungal activities of the oil were studied with regard to Aspergillus flavus growth inhibition and altered morphology, as preliminary studies indicated that the essential oil from C. longa inhibited Aspergillus flavus Link aflatoxin production. The concentration of essential oil in the culture media ranged from 0.01% to 5.0% v/v, and the concentration of curcumin was 0.01–0.5% v/v. The effects on sporulation, spore viability, and fungal morphology were determined. The essential oil exhibited stronger antifungal activity than curcumin on A. flavus. The essential oil reduced the fungal growth in a concentration-dependent manner. A. flavus growth rate was reduced by C. longa essential oil at 0.10%, and this inhibition effect was more efficient in concentrations above 0.50%. Germination and sporulation were 100% inhibited in 0.5% oil. Scanning electron microscopy (SEM) of A. flavus exposed to oil showed damage to hyphae membranes and conidiophores. Because the fungus is a plant pathogen and aflatoxin producer, C. longa essential oil may be used in the management of host plants. PMID:24367241

  2. Control of Aspergillus flavus in maize with plant essential oils and their components.

    PubMed

    Montes-Belmont, R; Carvajal, M

    1998-05-01

    The effects of 11 plant essential oils for maize kernel protection against Aspergillus flavus were studied. Tests were conducted to determine optimal levels of dosages for maize protection, effects of combinations of essential oils, and residual effects and toxicity of essential oils to maize plants. Principal constituents of eight essential oils were tested for ability to protect maize kernels. Essential oils of Cinnamomum zeylanicum (cinnamon), Mentha piperita (peppermint), Ocimum basilicum (basil), Origanum vulgare (origanum), Teloxys ambrosioides (the flavoring herb epazote), Syzygium aromaticum (clove), and Thymus vulgaris (thyme) caused a total inhibition of fungal development on maize kernels. Thymol and o-methoxycinnamaldehyde significantly reduced maize grain contamination. The optimal dosage for protection of maize varied from 3 to 8%. Combinations of C. zeylanicum with the remaining oils gave efficient control. A residual effect of C. zeylanicum was detected after 4 weeks of kernel treatment. No phytotoxic effect on germination and corn growth was detected with any of these oils.

  3. Inactivation of Aspergillus flavus spores in a sealed package by cold plasma streamers

    NASA Astrophysics Data System (ADS)

    Sohbatzadeh, F.; Mirzanejhad, S.; Shokri, H.; Nikpour, M.

    2016-06-01

    The main objective of this study is to investigate the inactivation efficacy of cold streamers in a sealed package on pathogenic fungi Aspergillus flavus ( A. flavus) spores that artificially contaminated pistachio surface. To produce penetrating cold streamers, electric power supply was adapted to deposit adequate power into the package. The plasma streamers were generated by an alternating high voltage with carrier frequency of 12.5 kHz which was suppressed by a modulated pulsed signal at frequency of 110 Hz. The plasma exposition time was varied from 8 to 18 min to show the effect of the plasma treatment on fungal clearance while the electrode and sample remained at room temperature. This proved a positive effect of the cold streamers treatment on fungal clearance. Benefits of deactivation of fungal spores by streamers inside the package include no heating, short treatment time and adaptability to existing processes. Given its ability to ensure the safety and longevity of food products, this technology has great potential for utilization in food packaging and processing industry. In this study, moisture and pH changes of pistachio samples after plasma streamers treatment were also investigated.

  4. Increased susceptibility and reduced phytoalexin accumulation in drought-stressed peanut kernels challenged with Aspergillus flavus.

    PubMed Central

    Wotton, H R; Strange, R N

    1987-01-01

    Three genotypes of peanut (Arachis hypogaea L.), with ICG numbers 221, 1104, and 1326, were grown in three replicate plots and drought stressed during the last 58 days before harvest by withholding irrigation water. Within each plot there were eight levels of stress ranging from 1.1 to 25.9 cm of water. Kernels harvested from the plots were hydrated to 20% moisture and challenged with Aspergillus flavus. Fungal colonization, aflatoxin content, and phytoalexin accumulation were measured. Fungal colonization of non-drought-stressed kernels virtually ceased by 3 days after inoculation, when the phytoalexin concentration exceeded 50 micrograms/g (fresh weight) of kernels, but the aflatoxin concentration continued to rise exponentially for an additional day. When fungal colonization, aflatoxin production, and phytoalexin accumulation were measured 3 days after drought-stressed material was challenged, the following relationships were apparent. Fungal colonization was inversely related to water supply (r varied from -0.848 to -0.904, according to genotype), as was aflatoxin production (r varied from -0.876 to -0.912, according to genotype); the phytoalexin concentration was correlated with water supply when this exceeded 11 cm (r varied from 0.696 to 0.917, according to genotype). The results are discussed in terms of the critical role played by drought stress in predisposing peanuts to infection by A. flavus and the role of the impaired phytoalexin response in mediating this increased susceptibility. PMID:3105455

  5. Genetic transformation system for the aflatoxin-producing fungus Aspergillus flavus.

    PubMed Central

    Woloshuk, C P; Seip, E R; Payne, G A; Adkins, C R

    1989-01-01

    A heterologous transformation system was developed for Aspergillus flavus with efficiencies greater than 20 stable transformants per micrograms of DNA. Protoplasts of uracil-requiring strains of the fungus were transformed with plasmid and cosmid vectors containing the pyr-4 gene of Neurospora crassa. Transformants were selected for their ability to grow and sporulate on medium lacking uracil. Vector DNA appeared to integrate randomly into the genome of A. flavus with a tendency for multiple, tandem insertion. Transformants with single or multiple insertions were stable after five consecutive transfers on medium containing uracil. Uracil-requiring recipient strains were obtained either by UV-irradiating conidia and selecting colonies resistant to 5-fluoroorotic acid or by transferring the mutated pyr locus to strains by parasexual recombination. This is the first report of a transformation system for an aflatoxin-producing fungus. The transformation system and the availability of aflatoxin-negative mutants provide a new approach to studying the biosynthesis and regulation of aflatoxin. Images PMID:2495764

  6. Survey of Thymus migricus essential oil on aflatoxin inhibition in Aspergillus flavus.

    PubMed

    Alizadeh, Alireza; Sharaifi, Rohollah; Javan-Nikkhah, Mohammad; Sedaghat, Narges

    2010-01-01

    Essential oil components as result of non host disease resistance of plants have high capability to introduce as alternative of chemical pesticides. Thymus migricus essential oil was selected to investigation of its antifungal activity on survival and growth of Aspergillus flavus. For obtain essential oil first Leaves and flowers of Th. migricus collected then dried. The Essential oil was extracted by means of hydro-distillation and afterwards GC-MS analysis was performed to identify their components. The main constituents that resulted were Thymol (44.9%), Geraniol (10.8%), gamma-Terpinene (10.3%), Citronellol (8.5%) and p-Cymene (7.2%). EC50 and MIC (Minimum Inhibitory Concentration) of Th. migricus oil against A. flavus was 324.42 microl/l and 451.62 microl/l, respectively. Whereas EC50 and MIC for chemical thiabendazol was 650 microl/l and 1635 microl/l, respectively. The EC50 and MIC concentrations of Th. migricus oil in antifungal activity examination were used in aflatoxin inhibition test. Result of HPTLC measurement showed that both of concentrations inhibit aflatoxin production completely compares to control with 7.63 ppm aflatoxin production. In other word, Th. migricus oil can suppress aflatoxin production in concentrations lower than EC50 for mycelium growth.

  7. Aspergillus flavus growth in the presence of chemical preservatives and naturally occurring antimicrobial compounds.

    PubMed

    López-Malo, Aurelio; Maris Alzamora, Stella; Palou, Enrique

    2005-03-15

    The combined effects of water activity ([a(w)] 0.99 or 0.95), pH (4.5 or 3.5) and antimicrobial agent (potassium sorbate, sodium benzoate, sodium bisulfite, carvacrol, citral, eugenol, thymol, or vanillin) concentration (0, 100, 200 up to 1800 ppm) on the growth of Aspergillus flavus were evaluated in potato dextrose agar (PDA). Mold spore germination time and radial growth rates (RGR) were significantly (p<0.05) affected by the variables. For equal antimicrobial concentration, reduction in pH or a(w) had important effects, lowering RGR and delaying germination time. Depending on a(w) and pH, increase in antimicrobial concentration slightly reduced RGR until a critical concentration where RGR was drastically reduced or mold growth was inhibited. Germination time increased as antimicrobial agent concentration increased and when a(w) and pH decreased. Important antimicrobial differences were observed, being, in general, the natural antimicrobials less pH-dependent than chemical preservatives. A. flavus exhibited higher sensitivity to thymol, eugenol, carvacrol, potassium sorbate, sodium bisulfite, and sodium benzoate (at pH 3.5) than to vanillin or citral.

  8. Identification of Fourier transform infrared photoacoustic spectral features for detection of Aspergillus flavus infection in corn.

    PubMed

    Gordon, S H; Schudy, R B; Wheeler, B C; Wicklow, D T; Greene, R V

    1997-04-01

    Aspergillus flavus and other pathogenic fungi display typical infrared spectra which differ significantly from spectra of substrate materials such as corn. On this basis, specific spectral features have been identified which permit detection of fungal infection on the surface of corn kernels by photoacoustic infrared spectroscopy. In a blind study, ten corn kernels showing bright greenish yellow fluorescence (BGYF) in the germ or endosperm and ten BGYF-negative kernels were correctly classified as infected or not infected by Fourier transform infrared photoacoustic spectroscopy. Earlier studies have shown that BGYF-positive kernels contain the bulk of the aflatoxin contaminating grain at harvest. Ten major spectral features, identified by visual inspection of the photoacoustic spectra of A. flavus mycelium grown in culture versus uninfected corn, were interpreted and assigned by theoretical comparisons of the relative chemical compositions of fungi and corn. The spectral features can be built into either empirical or knowledge-based computer models (expert systems) for automatic infrared detection and segregation of grains or kernels containing aflatoxin from the food and feed supply.

  9. A Novel Y319H Substitution in CYP51C Associated with Azole Resistance in Aspergillus flavus

    PubMed Central

    Paul, R. A.; Meis, J. F.

    2015-01-01

    This study aimed to explore any mutation in the CYP51 gene conferring azole resistance in Aspergillus flavus. Two voriconazole-resistant and 45 voriconazole-susceptible isolates were included in the study. Sequence analysis demonstrated a T1025C nucleotide change in CYP51C, resulting in the Y319H amino acid substitution in one resistant isolate. However, the earlier described T788G mutation in CYP51C conferring voriconazole resistance in A. flavus isolates was present in all isolates, irrespective of their susceptibility status. PMID:26248359

  10. Genome-wide transcriptome analysis of cotton (Gossypium hirsutum L.) identifies candidate gene signatures in response to aflatoxin producing fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are toxic metabolites and potent carcinogen produced from asexual fungi Aspergillus flavus and A. parasiticus. Aflatoxins can contaminate cottonseed under conducive preharvest and postharvest conditions. U.S. federal regulations restrict the use of aflatoxin contaminated cottonseed at >20...

  11. Global Phosphoproteomic Analysis Reveals the Involvement of Phosphorylation in Aflatoxins Biosynthesis in the Pathogenic Fungus Aspergillus flavus

    PubMed Central

    Ren, Silin; Yang, Mingkun; Li, Yu; Zhang, Feng; Chen, Zhuo; Zhang, Jia; Yang, Guang; Yue, Yuewei; Li, Siting; Ge, Feng; Wang, Shihua

    2016-01-01

    Aspergillus flavus is a pathogenic fungus that produces toxic and carcinogenic aflatoxins and is the causative agent of aflatoxicosis. A growing body of evidence indicates that reversible phosphorylation plays important roles in regulating diverse functions in this pathogen. However, only a few phosphoproteins of this fungus have been identified, which hampers our understanding of the roles of phosphorylation in A. flavus. So we performed a global and site-specific phosphoproteomic analysis of A. flavus. A total of 598 high-confidence phosphorylation sites were identified in 283 phosphoproteins. The identified phosphoproteins were involved in various biological processes, including signal transduction and aflatoxins biosynthesis. Five identified phosphoproteins associated with MAPK signal transduction and aflatoxins biosynthesis were validated by immunoblotting using phospho-specific antibodies. Further functional studies revealed that phosphorylation of the MAP kinase kinase kinase Ste11 affected aflatoxins biosynthesis in A. flavus. Our data represent the results of the first global survey of protein phosphorylation in A. flavus and reveal previously unappreciated roles for phosphorylation in the regulation of aflatoxins production. The generated dataset can serve as an important resource for the functional analysis of protein phosphorylation in A. flavus and facilitate the elucidation of phosphorylated signaling networks in this pathogen. PMID:27667718

  12. Transcriptome analysis of Aspergillus flavus reveals veA-dependent regulation of secondary metabolite gene clusters, including the novel aflavarin cluster

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The global regulatory veA gene governs development and secondary metabolism in numerous fungal species, including Aspergillus flavus. This is especially relevant since A. flavus infects crops of agricultural importance worldwide, contaminating them with potent mycotoxins. The most well-known are afl...

  13. Use of UHPLC high-resolution Orbitrap mass spectrometry to investigate the genes involved in the production of secondary metabolites in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Aspergillus flavus is known for its ability to produce the toxic and carcinogenic aflatoxins in food and feed. While aflatoxins are of most concern, A. flavus is predicted to be capable of producing many more metabolites based on a study of its complete genome sequence. Some of these meta...

  14. Environmental distribution and genetic diversity of vegetative compatibility groups determine biocontrol strategies to mitigate aflatoxin contamination of maize by Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize infected by aflatoxin-producing Aspergillus flavus may become contaminated with aflatoxins and as a result, threaten human health, food security, and farmers’ income in developing countries where maize is a staple. Environmental distribution and genetic diversity of A. flavus can influence the...

  15. Functional characterization of a veA-dependent polyketide synthase gene in Aspergillus flavus necessary for the synthesis of asparasone, a sclerotium-specific pigment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The filamentous fungus, Aspergillus flavus, produces the toxic and carcinogenic, polyketide synthase (PKS)-derived family of secondary metabolites termed aflatoxins. While analysis of the A. flavus genome has identified many other PKSs capable of producing secondary metabolites, to date, only a few ...

  16. rtfA, a putative RNA-Pol II transcription elongation factor gene, is necessary for normal morphological and chemical development in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The filamentous fungus Aspergillus flavus is an agriculturally important opportunistic plant pathogen that produces potent carcinogenic compounds called aflatoxins. We identified the A. flavus rtfA gene, the ortholog of rtf1 in S. cerevisiae and rtfA in A. nidulans. Interestingly, rtfA has multiple ...

  17. Analysis of an nsdC mutant in Aspergillus flavus reveals an extensive role in the regulation of several secondary metabolic gene clusters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a saprophytic fungus that can invade and contaminate agronomically important crops. The fungus produces a number of toxic secondary metabolites, such as aflatoxin, which are synthesized from genes located in close proximity with each other on the chromosome. A. flavus has appro...

  18. Identification of Aspergillus (A. flavus and A. niger) Allergens and Heterogeneity of Allergic Patients' IgE Response.

    PubMed

    Vermani, Maansi; Vijayan, Vannan Kandi; Agarwal, Mahendra Kumar

    2015-08-01

    Aspergillus species (A. flavus and A. niger) are important sources of inhalant allergens. Current diagnostic modalities employ crude Aspergillus extracts which only indicate the source to which the patient has been sensitized, without identifying the number and type of allergens in crude extracts. We report a study on the identification of major and minor allergens of the two common airborne Aspergillus species and heterogeneity of patients' IgE response to them. Skin prick tests were performed on 300 patients of bronchial asthma and/or allergic rhinitis and 20 healthy volunteers. Allergen specific IgE in patients' sera was estimated by enzyme allergosorbent test (EAST). Immunoblots were performed to identify major/minor allergens of Aspergillus extracts and to study heterogeneity of patients'IgE response to them. Positive cutaneous responses were observed in 17% and 14.7% of patients with A. flavus and A. niger extracts, respectively. Corresponding EAST positivity was 69.2% and 68.7%. In immunoblots, 5 allergenic proteins were identified in A. niger extract, major allergens being 49, 55.4 and 81.5 kDa. Twelve proteins bound patients' IgE in A. flavus extract, three being major allergens (13.3, 34 and 37 kDa). The position and slopes of EAST binding and inhibition curves obtained with individual sera varied from patient to patient. The number and molecular weight of IgE-binding proteins in both the Aspergillus extracts varied among patients. These results gave evidence of heterogeneity of patients' IgE response to major/minor Aspergillus allergens. This approach will be helpful to identify disease eliciting molecules in the individual patients (component resolved diagnosis) and may improve allergen-specific immunotherapy.

  19. Stimulation by Hyphopichia burtonii and Bacillus amyloliquefaciens of aflatoxin production by Aspergillus flavus in irradiated maize and rice grains

    SciTech Connect

    Cuero, R.G.; Smith, J.E.; Lacey, J.

    1987-05-01

    Aspergillus flavus was grown on maize and rice extract agars and on irradiated viable cracked maize and rice grains, either in pure culture or in dual culture with wild strains of either Hyphopichia burtonii or Bacillus amyloliquefaciens. Aflatoxin production by A. flavus and its growth and interactions with the other microorganisms were studied at three water activities (a/sub w/) (0.98, 0.95, and 0.90) and two temperatures (25 and 16/sup 0/C). Both H. burtonii and B. amyloliquefaciens markedly stimulated growth and aflotoxin production by A. flavus on cracked maize, especially at 25/sup 0/C and 0.95 and 0.98 a/sub w/. No aflatoxin was detected in pure cultures of A. flavus on cracked rice after 12 days of incubation at 25/sup 0/C, but some was produced by mixed cultures at 16/sup 0/C and 0.98 a/sub w/. The morphological interactions among A. flavus, H. burtonii, and B. amyloliquefaciens were also examined on maize and rice extract agars under similar controlled conditions.

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

    PubMed

    Gilbert, Matthew K; Mack, Brian M; Wei, Qijian; Bland, John M; Bhatnagar, Deepak; Cary, Jeffrey W

    2016-01-01

    The filamentous fungus, Aspergillus flavus (A. flavus) is an opportunistic pathogen capable of invading a number of crops and contaminating them with toxic secondary metabolites such as aflatoxins. Characterizing the molecular mechanisms governing growth and development of this organism is vital for developing safe and effective strategies for reducing crop contamination. The transcription factor nsdC has been identified as being required for normal asexual development and aflatoxin production in A. flavus. Building on a previous study using a large (L)-sclerotial morphotype A. flavus nsdC mutant we observed alterations in conidiophore development and loss of sclerotial and aflatoxin production using a nsdC mutant of a small (S)-sclerotial morphotype, that normally produces aflatoxin and sclerotia in quantities much higher than the L-morphotype. RNA sequencing analysis of the nsdC knockout mutant and isogenic control strain identified a number of differentially expressed genes related to development and production of secondary metabolites, including aflatoxin, penicillin and aflatrem. Further, RNA-seq data indicating down regulation of aflatrem biosynthetic gene expression in the nsdC mutant correlated with HPLC analyses showing a decrease in aflatrem levels. The current study expands the role of nsdC as a globally acting transcription factor that is a critical regulator of both asexual reproduction and secondary metabolism in A. flavus.

  1. ROS Involves the Fungicidal Actions of Thymol against Spores of Aspergillus flavus via the Induction of Nitric Oxide

    PubMed Central

    Shen, Qingshan; Zhou, Wei; Li, Hongbo; Hu, Liangbin; Mo, Haizhen

    2016-01-01

    Aspergillus flavus is a well-known pathogenic fungus for both crops and human beings. The acquisition of resistance to azoles by A. flavus is leading to more failures occurring in the prevention of infection by A. flavus. In this study, we found that thymol, one of the major chemical constituents of the essential oil of Monarda punctate, had efficient fungicidal activity against A. flavus and led to sporular lysis. Further studies indicated that thymol treatment induced the generation of both ROS and NO in spores, whereas NO accumulation was far later than ROS accumulation in response to thymol. By blocking ROS production with the inhibitors of NADPH oxidase, NO generation was also significantly inhibited in the presence of thymol, which indicated that ROS induced NO generation in A. flavus in response to thymol treatment. Moreover, the removal of either ROS or NO attenuated lysis and death of spores exposed to thymol. The addition of SNP (exogenous NO donor) eliminated the protective effects of the inhibitors of NADPH oxidase on thymol-induced lysis and death of spores. Taken together, it could be concluded that ROS is involved in spore death induced by thymol via the induction of NO. PMID:27196096

  2. Milk kefir: ultrastructure, antimicrobial activity and efficacy on aflatoxin B1 production by Aspergillus flavus.

    PubMed

    Ismaiel, Ahmed A; Ghaly, Mohamed F; El-Naggar, Ayman K

    2011-05-01

    The association of kefir microbiota was observed by electron microscopic examination. Scanning electron microscopic (SEM) observations revealed that kefir grain surface is very rough and the inner portions had scattered irregular holes on its surface. The interior of the grain comprised fibrillar materials which were interpreted as protein, lipid and a soluble polysaccharide, the kefiran complex that surrounds yeast and bacteria in the grain. Yeast was observed more clearly than bacteria on the outer portion of the grain. Transmission electron microscopic (TEM) observations of kefir revealed that the grain comprised a mixed culture of yeast and bacteria growing in close association with each other. Microbiota is dominated by budded and long-flattened yeast cells growing together with lactobacilli and lactococci bacteria. Bacterial cells with rounded ends were also observed in this mixed culture. Kefir grains, kefir suspensions, and kefiran were tested for antimicrobial activities against several bacterial and fungal species. The highest activity was obtained against Streptococcus faecalis KR6 and Fusarium graminearum CZ1. Growth of Aspergillus flavus AH3 producing for aflatoxin B1 for 10 days in broth medium supplemented with varying concentrations of kefir filtrate (%, v/v) showed that sporulation was completely inhibited at the higher concentrations of kefir filtrate (7-10%, v/v). The average values of both mycelial dry weights and aflatoxin B1 were completely inhibited at 10% (v/v). This is the first in vitro study about the antifungal characteristics of kefir against filamentous fungi which was manifested by applying its inhibitory effect on the productivity of aflatoxin B1 by A. flavus AH3.

  3. Misidentification of Aspergillus nomius and Aspergillus tamarii as Aspergillus flavus: characterization by internal transcribed spacer, β-Tubulin, and calmodulin gene sequencing, metabolic fingerprinting, and matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    PubMed

    Tam, Emily W T; Chen, Jonathan H K; Lau, Eunice C L; Ngan, Antonio H Y; Fung, Kitty S C; Lee, Kim-Chung; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

    2014-04-01

    Aspergillus nomius and Aspergillus tamarii are Aspergillus species that phenotypically resemble Aspergillus flavus. In the last decade, a number of case reports have identified A. nomius and A. tamarii as causes of human infections. In this study, using an internal transcribed spacer, β-tubulin, and calmodulin gene sequencing, only 8 of 11 clinical isolates reported as A. flavus in our clinical microbiology laboratory by phenotypic methods were identified as A. flavus. The other three isolates were A. nomius (n = 2) or A. tamarii (n = 1). The results corresponded with those of metabolic fingerprinting, in which the A. flavus, A. nomius, and A. tamarii strains were separated into three clusters based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC MS) analysis. The first two patients with A. nomius infections had invasive aspergillosis and chronic cavitary and fibrosing pulmonary and pleural aspergillosis, respectively, whereas the third patient had A. tamarii colonization of the airway. Identification of the 11 clinical isolates and three reference strains by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) showed that only six of the nine strains of A. flavus were identified correctly. None of the strains of A. nomius and A. tamarii was correctly identified. β-Tubulin or the calmodulin gene should be the gene target of choice for identifying A. flavus, A. nomius, and A. tamarii. To improve the usefulness of MALDI-TOF MS, the number of strains for each species in MALDI-TOF MS databases should be expanded to cover intraspecies variability.

  4. Autoxidated linolenic acid inhibits aflatoxin biosynthesis in Aspergillus flavus via oxylipin species.

    PubMed

    Yan, Shijuan; Liang, Yating; Zhang, Jindan; Chen, Zhuang; Liu, Chun-Ming

    2015-08-01

    Aflatoxins produced by Aspergillus species are among the most toxic and carcinogenic compounds in nature. Although it has been known for a long time that seeds with high oil content are more susceptible to aflatoxin contamination, the role of fatty acids in aflatoxin biosynthesis remains controversial. Here we demonstrate in A. flavus that both the saturated stearic acid (C18:0) and the polyunsaturated linolenic acid (C18:3) promoted aflatoxin production, while C18:3, but not C18:0, inhibited aflatoxin biosynthesis after exposure to air for several hours. Further experiments showed that autoxidated C18:3 promoted mycelial growth, sporulation, and kojic acid production, but inhibited the expression of genes in the AF biosynthetic gene cluster. Mass spectrometry analyses of autoxidated C18:3 fractions that were able to inhibit aflatoxin biosynthesis led to the identification of multiple oxylipin species. These results may help to clarify the role of fatty acids in aflatoxin biosynthesis, and may explain why controversial results have been obtained for fatty acids in the past.

  5. Nutritional changes in powdered red pepper upon in vitro infection of Aspergillus flavus

    PubMed Central

    Tripathi, Smita; Mishra, H.N.

    2009-01-01

    Quantitative losses in various biochemical constituents like capsaicin, carotenes, ascorbic acid, polyphenols, mineral matter, sugars (soluble and insoluble), protein and fat were estimated after the successful growth of Aspergillus flavus for 30 days on powdered red pepper. The fungal biomass was measured by ergosterol content and Aflatoxin B1 by HPLC. Amongst the various nutritional constituents evaluated for nutritional losses and changes the highest nutritional loss was reported in total carotenoids (88.55%) followed by total sugars (85.5%). The protein content of the infected sample increased from 18.01% to 23%. The nutritional profile of chilli powder (Capsicum annum var. sannam L.) shows highest share of total soluble sugars (32.89%) and fiber content (21.05%), followed by protein (18.01%) and fat (13.32%) making it an ideal solid- substrate for mould growth. At the end of incubation the fungal biomass was 192. 25 mg / 100 gram powder, total plate count 17.5 X 10 4 CFU/g and Aflatoxin B1 content was 30.06 μg / kg. PMID:24031333

  6. Effect of Zataria multiflora Boiss. essential oil on colony morphology and ultrastructure of Aspergillus flavus.

    PubMed

    Gandomi, Hassan; Misaghi, Ali; Basti, Afshin Akhondzadeh; Hamedi, Hassan; Shirvani, Zahra Ramezani

    2011-09-01

    The mode of inhibitory action of Zataria multiflora Boiss. essential oil (EO) on the fungus, Aspergillus flavus, was studied by colony morphology examination, light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The EO at concentrations used in this study suppressed the size of the colony as well as sporulation. SEM of mycelia treated with given concentrations of EO showed morphological alterations ranging from loss of turgidity and uniformity of mycelia at low concentrations of EO to evident destruction of the hyphae at higher concentration of EO. Semi-thin sections of mycelia exposed to different concentrations of EO were analysed by light microscopy and revealed that the major change at level as low as 50 ppm of EO was limited to vacuolisation of cytoplasm resulting in cell swelling, while at higher concentrations, detachment of the cell membrane from the cell wall, deformation of mycelia and shedding the cytoplasm from the cell were the main alterations. These damages were well documented by TEM, which showed that the main sites of action of EO were the plasma membrane and cell wall. In conclusion, morphological and structural changes observed in this study may be one of the mechanisms involved in growth inhibition of the fungi and reducing aflatoxin production.

  7. Comparative analysis of NBS-LRR genes and their response to Aspergillus flavus in Arachis

    PubMed Central

    Song, Hui; Wang, Pengfei; Li, Changsheng; Han, Suoyi; Zhao, Chuanzhi; Xia, Han; Bi, Yuping; Guo, Baozhu; Zhang, Xinyou

    2017-01-01

    Studies have demonstrated that nucleotide-binding site–leucine-rich repeat (NBS–LRR) genes respond to pathogen attack in plants. Characterization of NBS–LRR genes in peanut is not well documented. The newly released whole genome sequences of Arachis duranensis and Arachis ipaënsis have allowed a global analysis of this important gene family in peanut to be conducted. In this study, we identified 393 (AdNBS) and 437 (AiNBS) NBS–LRR genes from A. duranensis and A. ipaënsis, respectively, using bioinformatics approaches. Full-length sequences of 278 AdNBS and 303 AiNBS were identified. Fifty-one orthologous, four AdNBS paralogous, and six AiNBS paralogous gene pairs were predicted. All paralogous gene pairs were located in the same chromosomes, indicating that tandem duplication was the most likely mechanism forming these paralogs. The paralogs mainly underwent purifying selection, but most LRR 8 domains underwent positive selection. More gene clusters were found in A. ipaënsis than in A. duranensis, possibly owing to tandem duplication events occurring more frequently in A. ipaënsis. The expression profile of NBS–LRR genes was different between A. duranensis and A. hypogaea after Aspergillus flavus infection. The up-regulated expression of NBS–LRR in A. duranensis was continuous, while these genes responded to the pathogen temporally in A. hypogaea. PMID:28158222

  8. Effects of various acids and salts on growth and aflatoxin production by Aspergillus flavus NRRL 3145.

    PubMed

    Uraih, N; Chipley, J R

    1976-01-01

    The effects of sodium chloride, sodium acetate, benzoic acid, sodium benzoate, malonic acid, and sodium malonate on growth and aflatoxin production by Aspergillus flavus were investigated in synthetic media. Sodium chloride at concentrations equivalent to or greater than 12 g/100 ml inhibited growth and aflatoxin production, while at 8 g or less/100 ml, growth and aflatoxin production were stimulated. At 2 g or less/100 ml, sodium acetate also stimulated growth and aflatoxin production, but reduction occurred with 4 g or more/100 ml. Malonic acid at 10, 20, 40, and 50 mM reduced growth and aflatoxin production (over 50%) while sodium malonate at similar concentrations but different pH values had the opposite effect. Benzoic acid (pH 3.9) and sodium benzoate (pH 5.0) at 0.4 g/100 ml completely inhibited growth and aflatoxin production. Examination of the effect of initial pH indicated that the extent of inhibitory action of malonic acid and sodium acetate was a function of initial pH. The inhibitory action of benzoic acid and sodium benzoate appeared to be a function of undissociated benzoic acid molecules. Aflatoxin reduction was usually accompanied by an unidentified orange pigment, while aflatoxin stimulation was accompanied by unidentified blue and green fluorescent spots but with lower Rf values that aflatoxins B1, G1, B2, and G2 standards.

  9. Effect of climate change on Aspergillus flavus and aflatoxin B1 production.

    PubMed

    Medina, Angel; Rodriguez, Alicia; Magan, Naresh

    2014-01-01

    This review considers the available information on the potential impact of key environmental factors and their interactions on the molecular ecology, growth and aflatoxin production by Aspergillus flavus in vitro and in maize grain. The recent studies which have been carried out to examine the impact of water activity × temperature on aflatoxin biosynthesis and phenotypic aflatoxin production are examined. These have shown that there is a direct relationship between the relative expression of key regulatory and structural genes under different environmental conditions which correlate directly with aflatoxin B1 production. A model has been developed to integrate the relative expression of 10 biosynthetic genes in the pathway, growth and aflatoxin B1 (AFB1) production which was validated under elevated temperature and water stress conditions. The effect of interacting conditions of aw × temperature × elevated CO2 (2 × and 3 × existing levels) are detailed for the first time. This suggests that while such interacting environmental conditions have little effect on growth they do have a significant impact on aflatoxin biosynthetic gene expression (structural aflD and regulatory aflR genes) and can significantly stimulate the production of AFB1. While the individual factors alone have an impact, it is the combined effect of these three abiotic factors which have an impact on mycotoxin production. This approach provides data which is necessary to help predict the real impacts of climate change on mycotoxigenic fungi.

  10. Sexual Reproduction in Aspergillus flavus Sclerotia: Acquisition of Novel Alleles from Soil Populations and Uniparental Mitochondrial Inheritance

    PubMed Central

    Horn, Bruce W.; Gell, Richard M.; Singh, Rakhi; Sorensen, Ronald B.; Carbone, Ignazio

    2016-01-01

    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. flavus is heterothallic and laboratory crosses between strains of the opposite mating type produce progeny showing genetic recombination. Sclerotia formed in crops are dispersed onto the soil surface at harvest and are predominantly produced by single strains of one mating type. Less commonly, sclerotia may be fertilized during co-infection of crops with sexually compatible strains. In this study, laboratory and field experiments were performed to examine sexual reproduction in single-strain and fertilized sclerotia following exposure of sclerotia to natural fungal populations in soil. Female and male roles and mitochondrial inheritance in A. flavus were also examined through reciprocal crosses between sclerotia and conidia. Single-strain sclerotia produced ascospores on soil and progeny showed biparental inheritance that included novel alleles originating from fertilization by native soil strains. Sclerotia fertilized in the laboratory and applied to soil before ascocarp formation also produced ascospores with evidence of recombination in progeny, but only known parental alleles were detected. In reciprocal crosses, sclerotia and conidia from both strains functioned as female and male, respectively, indicating A. flavus is hermaphroditic, although the degree of fertility depended upon the parental sources of sclerotia and conidia. All progeny showed maternal inheritance of mitochondria from the sclerotia. Compared to A. flavus populations in crops, soil populations would provide a higher likelihood of exposure of sclerotia to sexually compatible strains and a more diverse source of genetic material for outcrossing. PMID:26731416

  11. Impact of the antifungal protein PgAFP from Penicillium chrysogenum on the protein profile in Aspergillus flavus.

    PubMed

    Delgado, Josué; Owens, Rebecca A; Doyle, Sean; Asensio, Miguel A; Núñez, Félix

    2015-10-01

    Antifungal proteins produced by molds are generally small, highly basic, and cysteine-rich. The best known effects of these proteins include morphological changes, metabolic inactivation, and membrane perturbation on sensitive fungi. Reactive oxygen species (ROS) generation leads to apoptosis, with G -protein playing a key role in transduction of cell death signals. The antifungal protein PgAFP from Penicillium chrysogenum inhibits growth of some toxigenic molds. Here we analyzed the effect of the antifungal protein PgAFP on the growth of Aspergillus flavus. For this, comparative proteomic analysis was used to identify the whole protein profile and protein change in abundance after PgAFP treatment. PgAFP provoked metabolic changes related to reduced energy metabolism, cell wall integrity alteration, and increased stress response due to higher levels of ROS. The observed changes in protein abundance, favoring a higher glutathione concentration as well as the increased abundance in heat shock proteins, do not seem to be enough to avoid necrosis. The decreased chitin deposition observed in PgAFP-treated A. flavus is attributed to a lower relative quantity of Rho1. The reduced relative abundance of a β subunit of G -protein seems to be the underlying reason for modulation of apoptosis in PgAFP-treated A. flavus hyphae. We propose Rho1 and G -protein subunit β CpcB to be the main factors in the mode of action of PgAFP in A. flavus. Additionally, enzymes essential for the biosynthesis of aflatoxin were no longer detectable in A. flavus hyphae at 24 h, following treatment with PgAFP. This presents a promising effect of PgAFP, which may prevent A. flavus from producing mycotoxins. However, the impact of PgAFP on actual aflatoxin production requires further study.

  12. Sexual Reproduction in Aspergillus flavus Sclerotia: Acquisition of Novel Alleles from Soil Populations and Uniparental Mitochondrial Inheritance.

    PubMed

    Horn, Bruce W; Gell, Richard M; Singh, Rakhi; Sorensen, Ronald B; Carbone, Ignazio

    2016-01-01

    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. flavus is heterothallic and laboratory crosses between strains of the opposite mating type produce progeny showing genetic recombination. Sclerotia formed in crops are dispersed onto the soil surface at harvest and are predominantly produced by single strains of one mating type. Less commonly, sclerotia may be fertilized during co-infection of crops with sexually compatible strains. In this study, laboratory and field experiments were performed to examine sexual reproduction in single-strain and fertilized sclerotia following exposure of sclerotia to natural fungal populations in soil. Female and male roles and mitochondrial inheritance in A. flavus were also examined through reciprocal crosses between sclerotia and conidia. Single-strain sclerotia produced ascospores on soil and progeny showed biparental inheritance that included novel alleles originating from fertilization by native soil strains. Sclerotia fertilized in the laboratory and applied to soil before ascocarp formation also produced ascospores with evidence of recombination in progeny, but only known parental alleles were detected. In reciprocal crosses, sclerotia and conidia from both strains functioned as female and male, respectively, indicating A. flavus is hermaphroditic, although the degree of fertility depended upon the parental sources of sclerotia and conidia. All progeny showed maternal inheritance of mitochondria from the sclerotia. Compared to A. flavus populations in crops, soil populations would provide a higher likelihood of exposure of sclerotia to sexually compatible strains and a more diverse source of genetic material for outcrossing.

  13. Rapid detection of aflatoxigenic Aspergillus sp. in herbal specimens by a simple, bendable, paper-based lab-on-a-chip.

    PubMed

    Chaumpluk, Piyasak; Plubcharoensook, Pattra; Prasongsuk, Sehanat

    2016-06-01

    Postharvest herbal product contamination with mycotoxins and mycotoxin-producing fungi represents a potentially carcinogenic hazard. Aspergillus flavus is a major cause of this issue. Available mold detection methods are PCR-based and rely heavily on laboratories; thus, they are unsuitable for on-site monitoring. In this study, a bendable, paper-based lab-on-a-chip platform was developed to rapidly detect toxigenic Aspergillus spp. DNA. The 3.0-4.0 cm(2) chip is fabricated using Whatman™ filter paper, fishing line and a simple plastic lamination process and has nucleic acid amplification and signal detection components. The Aspergillus assay specifically amplifies the aflatoxin biosynthesis gene, aflR, using loop-mediated isothermal amplification (LAMP); hybridization between target DNA and probes on blue silvernanoplates (AgNPls) yields colorimetric results. Positive results are indicated by the detection pad appearing blue due to dispersed blue AgNPls; negative results are indicated by the detection pad appearing colorless or pale yellow due to probe/target DNA hybridization and AgNPls aggregation. Assay completion requires less than 40 min, has a limit of detection (LOD) of 100 aflR copies, and has high specificity (94.47%)and sensitivity (100%). Contamination was identified in 14 of 32 herbal samples tested (43.75%). This work demonstrates the fabrication of a simple, low-cost, paper-based lab-on-a-chip platform suitable for rapid-detection applications.

  14. In vitro activities of five antifungal agents against 199 clinical and environmental isolates of Aspergillus flavus, an opportunistic fungal pathogen.

    PubMed

    Khodavaisy, S; Badali, H; Hashemi, S J; Aala, F; Nazeri, M; Nouripour-Sisakht, S; Sorkherizi, M S; Amirizad, K; Aslani, N; Rezaie, S

    2016-06-01

    Aspergillus flavus is the second leading cause of invasive and non-invasive aspergillosis, as well as the most common cause of fungal sinusitis, cutaneous infections, and endophthalmitis in tropical countries. Since resistance to antifungal agents has been observed in patients, susceptibility testing is helpful in defining the activity spectrum of antifungals and determining the appropriate drug for treatment. A collection of 199 clinical and environmental strains of Aspergillus flavus consisted of clinical (n=171) and environmental (n=28) were verified by DNA sequencing of the partial b-tubulin gene. MICs of amphotericin B, itraconazole, voriconazole, posaconazole, and MEC of caspofungin were determined in accordance with the Clinical and Laboratory Standards Institute M38-A2 document. Caspofungin, followed by posaconazole, exhibited the lowest minimum inhibitory concentrations (MIC). All isolates had caspofungin MEC90 (0.063μg/ml) lower than the epidemiologic cutoff values, and 3.5% of the isolates had amphotericin B MIC higher than the epidemiologic cutoff values. However, their clinical effectiveness in the treatment of A. flavus infection remains to be determined.

  15. Efficacy of two chemical coagulants and three different filtration media on removal of Aspergillus flavus from surface water.

    PubMed

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

    2014-02-01

    Aquatic fungi are common in various aqueous environments and play potentially crucial roles in nutrient and carbon cycling as well as interacting with other organisms. Species of Aspergillus are the most common fungi that occur in water. The present study was undertaken to elucidate the efficacy of two coagulants, aluminum sulfate and ferric chloride, used at different concentrations to treat drinking water, in removing Aspergillus flavus, as well as testing three different filtration media: sand, activated carbon, and ceramic granules, for their removal of fungi from water. The results revealed that both coagulants were effective in removing fungi and decreasing the turbidity of drinking water, and turbidity decreased with increasing coagulant concentration. Also, at the highest concentration of the coagulants, A. flavus was decreased by 99.6% in the treated water. Among ceramic granules, activated carbon, and sand used as media for water filtration, the sand and activated carbon filters were more effective in removing A. flavus than ceramic granules while simultaneously decreasing the turbidity levels in the test water samples. Post-treatment total organic carbon (TOC) and total nitrogen (TN) concentrations in the experimental water did not decrease; on the contrary, TN concentrations increased with the increasing dosage of coagulants. The filtration process had no effect in reducing TOC and TN in tested water.

  16. Effects of soil moisture and temperature on preharvest invasion of peanuts by the Aspergillus flavus group and subsequent aflatoxin development.

    PubMed Central

    Hill, R A; Blankenship, P D; Cole, R J; Sanders, T H

    1983-01-01

    Four soil temperature and moisture treatment regimens were imposed on Florunner peanuts 94 days after planting in experimental plots in 1980. At harvest (145 days after planting), the incidence of the Aspergillus flavus group and the aflatoxin concentration were greatest in damaged kernels. Extensive colonization of sound mature kernels (SMK) by the A. flavus group occurred with the drought stress treatment (56% kernels colonized); colonization was less in the irrigated plot (7%) and the drought stress plot with cooled soil (11%) and was intermediate in the irrigated plot with heated soil (26%). Aflatoxin was virtually absent from SMK with the last three treatments, but it was found at an average concentration of 244 ppb (ng/g) in drought-stressed SMK. Colonization of SMK by the A. flavus group and aflatoxin production were greater with hot dry conditions. Neither elevated temperature alone nor drought stress alone caused aflatoxin contamination in SMK. When the ratio of SMK colonized by A. flavus compared with A. niger was greater than 19:1, there was aflatoxin contamination, but there was none if this ratio was less than 9:1. Irrigation caused a higher incidence of A. niger than drought did. This may have prevented the aflatoxin contamination of undamaged peanuts. PMID:6402980

  17. Characterization of a fungistatic substance produced by Aspergillus flavus isolated from soil and its significance in nature.

    PubMed

    Chen, Yen-Ting; Lin, Mei-Ju; Yang, Ching-Hui; Ko, Wen-Hsiung

    2011-10-01

    A fungus capable of using vegetable tissues for multiplication in soil was isolated and identified as Aspergillus flavus based on morphological characteristics and sequence similarity of ITS and 28S. When grown in liquid medium prepared from the same vegetable tissues used in soil amendment, the isolate of A. flavus produced a substance capable of preventing disease development of black leaf spot of mustard cabbage caused by Alternaria brassicicola and inhibiting the germination of A. brassicicola conidia. The inhibitory substance was fungistatic, and was very stable under high temperature and high or low pH value. It was soluble in ethanol or methanol, moderately soluble in water, and insoluble in acetone, ethyl acetate or ether. The inhibitor is not a protein and has no charges on its molecule. This is the first discovery of the production of a fungistatic substance by this deleterious fungus. Results from this study suggest the possession of a strong competitive saprophytic ability by A. flavus, which in turn may explain the widespread occurrence of this fungus in soils. Production of a fungistatic substance when A. flavus was grown in medium prepared from vegetable tissues suggests the importance of antibiotic production in its competitive saprophytic colonization of organic matters in soils.

  18. Effect of water activity and temperature on growth of three Penicillium species and Aspergillus flavus on a sponge cake analogue.

    PubMed

    Abellana, M; Sanchis, V; Ramos, A J

    2001-12-30

    This study compared the effect of temperature and water activity and their interactions on the rate of mycelial growth of Penicillium aurantiogriseum, P. chrysogenum, P. corylophilum and Aspergillus flavus on a sponge cake analogue. As expected, growth rates showed dependence on a(w), and temperature. However, no significant differences were observed in the growth rates of different isolates. The minimum a(w) values for growth of the Penicillium spp. was 0.85-0.90. A. flavus was able to grow at 0.90 a(w) when the temperature was above 15 degrees C. This study has shown that fungal growth by these species on a sponge cake analogue, with a composition similar to usual bakery products, is prevented if the a(w) is kept at < 0.85.

  19. The Master Transcription Factor mtfA Governs Aflatoxin Production, Morphological Development and Pathogenicity in the Fungus Aspergillus flavus

    PubMed Central

    Zhuang, Zhenhong; Lohmar, Jessica M.; Satterlee, Timothy; Cary, Jeffrey W.; Calvo, Ana M.

    2016-01-01

    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 a number of economically-important crops, such as corn, cotton, peanut and tree nuts, and contaminating them with AFs. Molecular genetic studies in A. flavus could identify novel gene targets for use in strategies to reduce AF contamination and its adverse impact on food and feed supplies worldwide. In the current study, we investigated the role of the master transcription factor gene mtfA in A. flavus. Our results revealed that forced overexpression of mtfA results in a drastic decrease or elimination of several secondary metabolites, among them AFB1. The reduction in AFB1 was accompanied by a decrease in aflR expression. Furthermore, mtfA also regulates development; conidiation was influenced differently by this gene depending on the type of colonized substrate. In addition to its effect on conidiation, mtfA is necessary for the normal maturation of sclerotia. Importantly, mtfA positively affects the pathogenicity of A. flavus when colonizing peanut seeds. AF production in colonized seeds was decreased in the deletion mtfA strain and particularly in the overexpression strain, where only trace amounts were detected. Interestingly, a more rapid colonization of the seed tissue occurred when mtfA was overexpressed, coinciding with an increase in lipase activity and faster maceration of the oily part of the seed. PMID:26805883

  20. Isolation of Alkaline and Neutral Proteases from Aspergillus flavus var. columnaris, a Soy Sauce Koji Mold

    PubMed Central

    Impoolsup, Attawut; Bhumiratana, Amaret; Flegel, Timothy W.

    1981-01-01

    Two different extracellular proteases, protease I (P-I), an alkaline protease, and protease II (P-II) a neutral protease, from Aspergillus flavus var. columnaris were partially purified by using (NH4)2SO4 precipitation, diethylaminoethyl-Sephadex A-50 chromatography, carboxymethylcellulose CM-52 chromatography, and Sephadex G-100 gel filtration. The degree of purity was followed using polyacrylamide gel electrophoresis. The activity of P-I was completely inhibited by 0.1 mM phenylmethylsulfonyl fluoride, and that of P-II was completely inhibited by 1 mM ethylenediaminetetraacetate. By using these inhibitors with extracts of wheat bran koji, the proportions of total activity that could be assigned to P-I and P-II were 80 and 20%, respectively. This compared favorably with activities estimated by using polyacrylamide gel electrophoresis slices (82 and 18%, respectively). Extracts from factory-run soybean koji gave comparable results. Both enzymes demonstrated maximum activity at 50 to 55°C and only small changes in activity between pH 6 and 11. For P-I, activity was somewhat higher from pH 8.0 to 11.0, whereas for P-II it was somewhat higher from pH 6 to 9. In the presence of 18% NaCl, the activities of both P-I and P-II dropped by approximately 90 and 85%, respectively. P-I was inferred to possess aminopeptidase activity since it could hydrolyze l-leucyl-p-nitroanilide hydrochloride. P-II was devoid of such activity. The ramifications of the results for factory-produced soy sauce koji are discussed. Images PMID:16345858

  1. A Caleosin-Like Protein with Peroxygenase Activity Mediates Aspergillus flavus Development, Aflatoxin Accumulation, and Seed Infection

    PubMed Central

    Almousally, Ibrahem; Shaban, Mouhnad; Blee, Elizabeth

    2015-01-01

    Caleosins are a small family of calcium-binding proteins endowed with peroxygenase activity in plants. Caleosin-like genes are present in fungi; however, their functions have not been reported yet. In this work, we identify a plant caleosin-like protein in Aspergillus flavus that is highly expressed during the early stages of spore germination. A recombinant purified 32-kDa caleosin-like protein supported peroxygenase activities, including co-oxidation reactions and reduction of polyunsaturated fatty acid hydroperoxides. Deletion of the caleosin gene prevented fungal development. Alternatively, silencing of the gene led to the increased accumulation of endogenous polyunsaturated fatty acid hydroperoxides and antioxidant activities but to a reduction of fungal growth and conidium formation. Two key genes of the aflatoxin biosynthesis pathway, aflR and aflD, were downregulated in the strains in which A. flavus PXG (AfPXG) was silenced, leading to reduced aflatoxin B1 production in vitro. Application of caleosin/peroxygenase-derived oxylipins restored the wild-type phenotype in the strains in which AfPXG was silenced. PXG-deficient A. flavus strains were severely compromised in their capacity to infect maize seeds and to produce aflatoxin. Our results uncover a new branch of the fungal oxylipin pathway and may lead to the development of novel targets for controlling fungal disease. PMID:26116672

  2. Effects of Cymbopogon citratus L. essential oil on the growth, morphogenesis and aflatoxin production of Aspergillus flavus ML2-strain.

    PubMed

    Helal, G A; Sarhan, M M; Abu Shahla, A N K; Abou El-Khair, E K

    2007-02-01

    The mycelial growth of Aspergillus flavus Link was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek's liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 65% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. flavus hyphae after treatment with C. citratus essential oil. The hyphal diameter decreased and hyphal wall appeared as precipitates and disappeared in some regions. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca(+2), K(+) and Mg(+2) leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated and unsaturated fatty acids increased. One of the most important results obtained during this study was the ability of C. citratus essential oil at its sublethal dose to completely inhibit aflatoxin B(1) production from A. flavus. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegradation and storage contaminating fungi and also in fruit juice preservation.

  3. Beyond aflatoxin: four distinct expression patterns and functional roles associated with Aspergillus flavus secondary metabolism gene clusters

    PubMed Central

    Georgianna, D. Ryan; Fedorova, Natalie D.; Burroughs, James L.; Dolezal, Andrea L.; Bok, J.; Horowitz-Brown, S.; Woloshuk, Charles P.; Yu, Jiujiang; Keller, Nancy P.; Payne, Gary A.

    2014-01-01

    SUMMARY Species of Aspergillus produce a diverse array of secondary metabolites, and recent genomic analysis predicts that these species have the capacity to synthesize many more compounds. It has been possible to infer the presence of 55 gene clusters associated with secondary metabolism in A. flavus, however, only three metabolic pathways - aflatoxin, cyclopiazonic acid (CPA), and aflatrem - have been assigned to these clusters. To gain insight into the regulation of, and infer ecological significance for the 55 secondary metabolite gene clusters predicted in A. flavus, we examined their expression over 28 diverse conditions. Variables included culture media and temperature, fungal development, colonization of developing maize seeds, and misexpression of laeA, a global regulator of secondary metabolism. Hierarchical clustering analysis of expression profiles allowed us to categorize the gene clusters into four distinct clades. Gene clusters for the production of aflatoxins, CPA, and seven other unknown compound(s) were identified as belonging to one clade. To further explore the relationships found by gene expression analysis, aflatoxin and CPA production were quantified under five different cell culture environments known to be conducive or non-conducive for aflatoxin biosynthesis and during colonization of developing maize seeds. Results from these studies showed that secondary metabolism gene clusters have distinctive gene expression profiles. Aflatoxin and CPA were found to have unique regulation but are similar enough that they would be expected to co-occur in substrates colonized with A. flavus. PMID:20447271

  4. Effect of Various Compounds Blocking the Colony Pigmentation on the Aflatoxin B1 Production by Aspergillus flavus

    PubMed Central

    Dzhavakhiya, Vitaly G.; Voinova, Tatiana M.; Popletaeva, Sofya B.; Statsyuk, Natalia V.; Limantseva, Lyudmila A.; Shcherbakova, Larisa A.

    2016-01-01

    Aflatoxins and melanins are the products of a polyketide biosynthesis. In this study, the search of potential inhibitors of the aflatoxin B1 (AFB1) biosynthesis was performed among compounds blocking the pigmentation in fungi. Four compounds—three natural (thymol, 3-hydroxybenzaldehyde, compactin) and one synthetic (fluconazole)—were examined for their ability to block the pigmentation and AFB1 production in Aspergillus flavus. All compounds inhibited the mycelium pigmentation of a fungus growing on solid medium. At the same time, thymol, fluconazole, and 3-hydroxybenzaldehyde stimulated AFB1 accumulation in culture broth of A. flavus under submerged fermentation, whereas the addition of 2.5 μg/mL of compactin resulted in a 50× reduction in AFB1 production. Moreover, compactin also suppressed the sporulation of A. flavus on solid medium. In vivo treatment of corn and wheat grain with compactin (50 μg/g of grain) reduced the level of AFB1 accumulation 14 and 15 times, respectively. Further prospects of the compactin study as potential AFB1 inhibitor are discussed. PMID:27801823

  5. Identification and quantification of a toxigenic and non-toxigenic Aspergillus flavus strain in contaminated maize using quantitative real-time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins, which are produced by the fungus Aspergillus flavus, are toxic to humans, livestock, and pets. The value of maize (Zea mays) grain is markedly reduced when contaminated with aflatoxin. Plant resistance and biological control using non-toxin producing strains are considered effective st...

  6. Transcriptome analysis of Aspergillus flavus reveals isolate specific gene profiles in the response to oxidative stresses and carbon sources in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination of peanut and maize is exacerbated by drought stress. Reactive oxygen species (ROS) are produced in host plants during drought/heat stress, and are hypothesized to stimulate aflatoxin production. In order to better understand why Aspergillus flavus produces aflatoxin and the ...

  7. The major volatile compound 2-phenylethanol from the biocontrol yeast Pichia anomala inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a globally distributed fungus and an important food contaminant because it produces the most potent natural carcinogenic compound known as aflatoxin (AF) B1. The major volatile from a yeast strain, Pichia anomala WRL-076 was identified by SPEM-GC/MS analysis to be 2-phenylethan...

  8. A public platform for the verification of the phenotypic effect of candidate genes for resistance to aflatoxin accumulation and Aspergillus flavus infection in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A public candidate gene testing pipeline for resistance to aflatoxin accumulation or Aspergillus flavus infection in maize is presented here. The pipeline consists of steps for identifying, testing, and verifying the association of any maize gene sequence with resistance under field conditions. Reso...

  9. An Aspergillus flavus secondary metabolic gene cluster containing a hybrid PKS-NRPS is necessary for synthesis of the 2-pyridones, leporins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of the filamentous fungus, Aspergillus flavus, has been shown to harbor as many as 55 putative secondary metabolic gene clusters including the one responsible for production of the toxic and carcinogenic, polyketide synthase (PKS)-derived family of secondary metabolites termed aflatoxins....

  10. RNAi silencing of the 14 kDa trypsin inhibitor protein in maize and its effect on host resistance against Aspergillus flavus infection/aflatoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays L.) is one of the major crops susceptible to Aspergillus flavus Link ex. Fries infection and subsequent aflatoxin contamination. Previous studies found the expression of an antifungal 14 kDa trypsin inhibitor (TI) was associated with maize aflatoxin resistance. To further investigate...

  11. Application of a modified culture medium for the simultaneous counting of molds and yeasts and detection of aflatoxigenic strains of Aspergillus flavus and Aspergillus parasiticus.

    PubMed

    Jaimez, J; Fente, C A; Franco, C M; Cepeda, A; Vázquez, B I

    2003-02-01

    Molds and yeasts from 91 samples of feed and raw materials used in feed formulation were enumerated on a new culture medium to which a beta cyclodextrin (beta-W7M 1.8-cyclodextrin) had been added. This medium was compared with other media normally used in laboratories for the routine analysis of fungi, such as Sabouraud agar, malt agar supplemented with 2% dextrose, and potato dextrose agar. When a t test for paired data (0.05 significance level, 95% confidence interval) was applied, no statistically significant differences between the results obtained with the new culture medium and those obtained with the other media used to enumerate molds and yeasts were found. For the evaluation of contamination due to aflatoxin for all of the samples, Sabouraud agar and yeast extract agar, both supplemented with 0.3% beta-W7M 1.8-cyclodextrin, and APA (aflatoxin-producing ability) medium were used. Aflatoxin was detected in 21% of the feed samples and in 23% of the raw-material samples analyzed, with maximal amounts of 2.8 and 6.0 microg of aflatoxin B1 per kg, respectively, being detected. In any case, the aflatoxin contents found exceeded the legally stipulated limits. The t test for paired data (0.05 significance level, 95% confidence interval) did not show statistically significant differences between the results obtained with the different culture media used for the detection of aflatoxins. The advantage of the new medium developed (Sabouraud agar with 0.3% beta-W7M 1.8-cyclodextrin) is that it allows simultaneous fungal enumeration and determination (under UV light) of the presence of aflatoxin-producing strains without prior isolation and culture procedures involving expensive and/or complex specific media and thus saves work, time, and money.

  12. Could biorational insecticides be used in the management of aflatoxigenic Aspergillus parasiticus and its insect vectors in stored wheat?

    PubMed Central

    Khan, Tiyyabah; Shahid, Ahmad Ali

    2016-01-01

    Insect pests in stored wheat cause significant losses and play an important role in the dispersal of viable fungal spores of various species including aflatoxin producing Aspergillus parasiticus. The problem of insecticide resistance in stored insects and environmental hazards associated with fumigants and conventional grain protectants underscore the need to explore reduced risk insecticides to control stored insects with the ultimate effect on aflatoxin production. The purpose of this study was to investigate the insecticidal potential of four biorational insecticides: spinosad, thiamethoxam, imidacloprid and indoxacarb, on wheat grains artificially infested with Rhyzopertha dominica/Sitophilus oryzae and/or A. parasiticus spores, and the subsequent effect on aflatoxin production. Spinosad and thiamethoxam were the most effective insecticides against R. dominica compared to S. oryzae followed by imidacloprid. Spinosad applied at 0.25–1 ppm and thiamethoxam at 2 and 4 ppm concentrations resulted in complete mortality of R. dominica. However, indoxacarb was more toxic against S. oryzae compared to R. dominica. Wheat grains inoculated with R. dominica/S. oryzae +spores elicited higher aflatoxin levels than wheat grains inoculated with or without insecticide+spores. In all the treatment combinations containing insects, aflatoxin production was dependent on insects’ survival rate. In addition, thiamethoxam and imidacloprid had also a significant direct effect on reducing aflatoxin production. Aflatoxin levels were lower in the treatment combinations with any concentration of thiamethoxam/imidacloprid+spores as compared to wheat grains inoculated with spores only. Correlation analyses revealed highly significant and positive association between moisture contents/insect survival rate and production of aflatoxin levels, and insect survival rate and moisture contents of the wheat grains. In conclusion, the results of the present study provide baseline data on the use

  13. Pyrolysis-gas-liquid chromatography of fungi: differentiation of species and strains of several members of the Aspergillus flavus group.

    PubMed

    Vincent, P G; Kulik, M M

    1970-12-01

    Four fungi of the Aspergillus flavus group were differentiated to the species level and strain level by pyrolysis-gas-liquid chromotography. Comparisons of pyrochromatograms revealed more similarities than dissimilarities among both species and strains in the pyrolytic elution patterns. Quantitative analysis was made by comparing the number of peaks in which two strains or reference species agreed or disagreed, the degree of superimposability between the pyrolytic elution patterns of strains and reference species, and the presence or absence of peaks for strain pairs within each species. The accuracy and precision of these techniques suggest that pyrolysis-gas-liquid chromatography may have wide application in the detection, enumeration, and identification of fungi by nonmycologically trained personnel.

  14. The inhibitory effect of Bacillus megaterium on aflatoxin and cyclopiazonic acid biosynthetic pathway gene expression in Aspergillus flavus.

    PubMed

    Kong, Qing; Chi, Chen; Yu, Jiujiang; Shan, Shihua; Li, Qiyu; Li, Qianting; Guan, Bin; Nierman, William C; Bennett, Joan W

    2014-06-01

    Aspergillus flavus is one of the major moulds that colonize peanut in the field and during storage. The impact to human and animal health, and to the economy in agriculture and commerce, is significant since this mold produces the most potent known natural toxins, aflatoxins, which are carcinogenic, mutagenic, immunosuppressive, and teratogenic. A strain of marine Bacillus megaterium isolated from the Yellow Sea of East China was evaluated for its effect in inhibiting aflatoxin formation in A. flavus through down-regulating aflatoxin pathway gene expression as demonstrated by gene chip analysis. Aflatoxin accumulation in potato dextrose broth liquid medium and liquid minimal medium was almost totally (more than 98 %) inhibited by co-cultivation with B. megaterium. Growth was also reduced. Using expression studies, we identified the fungal genes down-regulated by co-cultivation with B. megaterium across the entire fungal genome and specifically within the aflatoxin pathway gene cluster (aflF, aflT, aflS, aflJ, aflL, aflX). Modulating the expression of these genes could be used for controlling aflatoxin contamination in crops such as corn, cotton, and peanut. Importantly, the expression of the regulatory gene aflS was significantly down-regulated during co-cultivation. We present a model showing a hypothesis of the regulatory mechanism of aflatoxin production suppression by AflS and AflR through B. megaterium co-cultivation.

  15. Effect of Zataria multiflora Boiss. essential oil on growth and aflatoxin formation by Aspergillus flavus in culture media and cheese.

    PubMed

    Gandomi, Hassan; Misaghi, Ali; Basti, Afshin Akhondzadeh; Bokaei, Saeed; Khosravi, Alireza; Abbasifar, Arash; Javan, Ashkan Jebelli

    2009-10-01

    The effect of Zataria multiflora Boiss. essential oil (EO) against growth, spore production and aflatoxin formation by Aspergillus flavus ATCC 15546 was investigated in synthetic media as well as Iranian ultra-filtered white cheese in brine. EO effectively inhibited radial growth and spore production on potato dextrose agar (PDA) in a dose-dependent manner. At 200 ppm, the radial growth and sporulation reduced by 79.4% and 92.5%, respectively. The growth was completely prevented at EO400 ppm on PDA, and minimum fungicidal concentration (MFC) of the oil was estimated at 1000 ppm. The oil also significantly suppressed mycelial growth and aflatoxin synthesis in broth medium at all concentrations tested (P<0.05). At 150 ppm of EO, the mycelial growth and aflatoxin accumulation reduced by 90% and 99.4%, respectively. The EO at all concentrations tested, had an inhibitory effect against radial fungal growth and aflatoxin production by A. flavus in cheese. However, no concentration of EO examined was able to completely inhibit the growth and aflatoxin production in cheese. The results suggested the potential substitution of the antifungal chemicals by this EO as a natural inhibitor to control the growth of molds in foods such as cheese.

  16. Effect of Citrus reticulata and Cymbopogon citratus essential oils on Aspergillus flavus growth and aflatoxin production on Asparagus racemosus.

    PubMed

    Singh, Priyanka; Shukla, Ravindra; Kumar, Ashok; Prakash, Bhanu; Singh, Shubhra; Dubey, Nawal Kishore

    2010-09-01

    Essential oils extracted from Citrus reticulata and Cymbopogon citratus were tested in vitro against the toxigenic strain of Aspergillus flavus, isolated from the tuberous roots of Asparagus racemosus, used in preparation of herbal drugs. The essential oils completely inhibited the growth of A. flavus at 750 ppm and also exhibited a broad fungitoxic spectrum against nine additional fungi isolated from the roots. Citrus reticulata and Cymbopogon citratus essential oils completely inhibited aflatoxin B(1) production at 750 and 500 ppm, respectively. During in vivo investigation, the incidence of fungi and aflatoxin B(1) production decreased considerably in essential oil-treated root samples. The findings thus indicate possible exploitation of the essential oils as effective inhibitor of aflatoxin B(1) production and as post-harvest fungitoxicant of traditionally used plant origin for the control of storage fungi. These essential oils may be recommended as plant-based antifungals as well as aflatoxin B(1) suppressors in post-harvest processing of herbal samples.

  17. Antifungal activity evaluation of Mexican oregano (Lippia berlandieri Schauer) essential oil on the growth of Aspergillus flavus by gaseous contact.

    PubMed

    Gómez-Sánchez, Aída; Palou, Enrique; López-Malo, Aurelio

    2011-12-01

    The antifungal activity of Mexican oregano (Lippia berlandieri Schauer) essential oil by gaseous contact on the growth of Aspergillus flavus at selected essential oil concentrations (14.7, 29.4, 58.8, or 117.6 μl of essential oil per liter of air) and temperatures (25, 30, or 35°C) was evaluated in potato dextrose agar formulated at water activity of 0.98 and pH 4.0. Mold growth curves were adequately fitted (0.984 < R(2) < 0.999) by the modified Gompertz model. The effect of the independent variables (concentration of essential oil and temperature) on the estimated model parameters (reciprocal of growth rate [1/ν(m)] and lag time [λ]) were evaluated through polynomial equations. Both ν(m) and λ were significantly (P < 0.05) affected by the independent variables; ν(m) decreased and λ increased as essential oil concentration increased and temperature decreased, which suggests that Mexican oregano essential oil retards or inhibits mold germination stage. Further, minimum fungistatic and fungicide essential oil concentrations at 30 and 35°C were determined. Mexican oregano essential oil applied in gas phase exerts important antifungal activity on the growth of A. flavus, suggesting its potential to inhibit other food spoilage molds.

  18. Cinnamaldehyde inhibits fungal growth and aflatoxin B1 biosynthesis by modulating the oxidative stress response of Aspergillus flavus.

    PubMed

    Sun, Qi; Shang, Bo; Wang, Ling; Lu, Zhisong; Liu, Yang

    2016-02-01

    Cinnamaldehyde (CIN) is a promising natural preservative and generally recognized as safe for commodities as well as consumers. In this work, the antifungal effects of CIN on Aspergillus flavus were evaluated both in solid and in liquid culture conditions. Our results indicated that CIN effectively inhibited radial growth, spore production, mycelium formation, and aflatoxin B1 biosynthesis by A. flavus in a dose-dependent manner. At the concentration of 104 mg L(-1), CIN exposure was able to completely inhibit fungal growth as well as aflatoxin B1 production. Furthermore, the inhibitory activities of CIN were closely connected with the treatment period and the tested fungal species. Compared with the control strains, CIN dose dependently changed the morphology and ultrastructure of mycelium in different degree. Especially, the reduction of hydrogen peroxide was considered to follow the destruction of mitochondrial. Meanwhile, CIN significantly cut the levels of lipid peroxidation and reduced glutathione. The activity of total superoxide dismutase was significantly inhibited after CIN treatment at the end of incubation, whereas the activities of catalase and glutathione peroxidase were opposite. These results indicated that the inhibitory effect of CIN could attribute to oxidative stress alleviation possibly induced by modifications of cellular structure as well as redox status.

  19. Analysis of genetic and aflatoxin diversity among Aspergillus flavus strains isolated from sorghum seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 34 A. flavus isolates were recovered from sorghum seeds sampled across five states in India. Our study included (1) species confirmation through PCR assay, (2) an aflatoxin cluster genotype assay using developed multiplex PCR, (3) quantification of total aflatoxin concentrations by the iC...

  20. Transcriptional profiles uncover Aspergillus flavus-induced resistance in maize kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin contamination caused by the opportunistic pathogen A. flavus is a major concern in maize production prior to harvest and during storage, and also a concern in many other crops, such as peanuts, cottonseed, tree nuts, and rice. Although a number of resistant maize lines with low aflatoxin c...

  1. Inhibition of the Aspergillus flavus Growth and Aflatoxin B1 Contamination on Pistachio Nut by Fengycin and Surfactin-Producing Bacillus subtilis UTBSP1

    PubMed Central

    Farzaneh, Mohsen; Shi, Zhi-Qi; Ahmadzadeh, Masoud; Hu, Liang-Bin; Ghassempour, Alireza

    2016-01-01

    In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut. PMID:27298596

  2. A Network Approach of Gene Co-expression in the Zea mays/Aspergillus flavus Pathosystem to Map Host/Pathogen Interaction Pathways

    PubMed Central

    Musungu, Bryan M.; Bhatnagar, Deepak; Brown, Robert L.; Payne, Gary A.; OBrian, Greg; Fakhoury, Ahmad M.; Geisler, Matt

    2016-01-01

    A gene co-expression network (GEN) was generated using a dual RNA-seq study with the fungal pathogen Aspergillus flavus and its plant host Zea mays during the initial 3 days of infection. The analysis deciphered novel pathways and mapped genes of interest in both organisms during the infection. This network revealed a high degree of connectivity in many of the previously recognized pathways in Z. mays such as jasmonic acid, ethylene, and reactive oxygen species (ROS). For the pathogen A. flavus, a link between aflatoxin production and vesicular transport was identified within the network. There was significant interspecies correlation of expression between Z. mays and A. flavus for a subset of 104 Z. mays, and 1942 A. flavus genes. This resulted in an interspecies subnetwork enriched in multiple Z. mays genes involved in the production of ROS. In addition to the ROS from Z. mays, there was enrichment in the vesicular transport pathways and the aflatoxin pathway for A. flavus. Included in these genes, a key aflatoxin cluster regulator, AflS, was found to be co-regulated with multiple Z. mays ROS producing genes within the network, suggesting AflS may be monitoring host ROS levels. The entire GEN for both host and pathogen, and the subset of interspecies correlations, is presented as a tool for hypothesis generation and discovery for events in the early stages of fungal infection of Z. mays by A. flavus. PMID:27917194

  3. A Network Approach of Gene Co-expression in the Zea mays/Aspergillus flavus Pathosystem to Map Host/Pathogen Interaction Pathways.

    PubMed

    Musungu, Bryan M; Bhatnagar, Deepak; Brown, Robert L; Payne, Gary A; OBrian, Greg; Fakhoury, Ahmad M; Geisler, Matt

    2016-01-01

    A gene co-expression network (GEN) was generated using a dual RNA-seq study with the fungal pathogen Aspergillus flavus and its plant host Zea mays during the initial 3 days of infection. The analysis deciphered novel pathways and mapped genes of interest in both organisms during the infection. This network revealed a high degree of connectivity in many of the previously recognized pathways in Z. mays such as jasmonic acid, ethylene, and reactive oxygen species (ROS). For the pathogen A. flavus, a link between aflatoxin production and vesicular transport was identified within the network. There was significant interspecies correlation of expression between Z. mays and A. flavus for a subset of 104 Z. mays, and 1942 A. flavus genes. This resulted in an interspecies subnetwork enriched in multiple Z. mays genes involved in the production of ROS. In addition to the ROS from Z. mays, there was enrichment in the vesicular transport pathways and the aflatoxin pathway for A. flavus. Included in these genes, a key aflatoxin cluster regulator, AflS, was found to be co-regulated with multiple Z. mays ROS producing genes within the network, suggesting AflS may be monitoring host ROS levels. The entire GEN for both host and pathogen, and the subset of interspecies correlations, is presented as a tool for hypothesis generation and discovery for events in the early stages of fungal infection of Z. mays by A. flavus.

  4. Mycotoxin production and predictive modelling kinetics on the growth of Aspergillus flavus and Aspergillus parasiticus isolates in whole black peppercorns (Piper nigrum L).

    PubMed

    Yogendrarajah, Pratheeba; Vermeulen, An; Jacxsens, Liesbeth; Mavromichali, Evangelia; De Saeger, Sarah; De Meulenaer, Bruno; Devlieghere, Frank

    2016-07-02

    The growth and mycotoxin production of three Aspergillus flavus isolates and an Aspergillus parasiticus isolate were studied in whole black peppercorns (Piper nigrum L.) using a full factorial design with seven water activity (aw) (0.826-0.984) levels and three temperatures (22, 30 and 37°C). Growth rates and lag phases were estimated using linear regression. Diverse secondary models were assessed for their ability to describe the radial growth rate as a function of individual and combined effect of aw and temperature. Optimum radial growth rate ranged from 0.75±0.04 to 2.65±0.02mm/day for A. flavus and 1.77±0.10 to 2.50±0.10mm/day for A. parasiticus based on the Rosso cardinal estimations. Despite the growth failure of some isolates at marginal conditions, all the studied models showed good performance to predict the growth rates. Validation of the models was performed on independently derived data. The bias factors (0.73-1.03), accuracy factors (0.97-1.36) and root mean square error (0.050-0.278) show that the examined models are conservative predictors of the colony growth rate of both fungal species in black peppers. The Rosso cardinal model can be recommended to describe the individual aw effect while the extended Gibson model was the best model for describing the combined effect of aw and temperature on the growth rate of both fungal species in peppercorns. Temperature optimum ranged from 30 to 33°C, while aw optimum was 0.87-0.92 as estimated by multi-factorial cardinal model for both species. The estimated minimum temperature and aw for A. flavus and A. parasiticus for growth were 11-16°C and 0.73-0.76, respectively, hence, achieving these conditions should be considered during storage to prevent the growth of these mycotoxigenic fungal species in black peppercorns. Following the growth study, production of mycotoxins (aflatoxins B1, B2, G1, G2, sterigmatocystin and O-methyl sterigmatocystin (OMST)) was quantified using LC-MS/MS. Very small

  5. Development of the dichlorvos-ammonia (DV-AM) method for the visual detection of aflatoxigenic fungi.

    PubMed

    Yabe, Kimiko; Hatabayashi, Hidemi; Ikehata, Akifumi; Zheng, Yazhi; Kushiro, Masayo

    2015-12-01

    Aflatoxins (AFs) are carcinogenic and toxic secondary metabolites produced mainly by Aspergillus flavus and Aspergillus parasiticus. To monitor and regulate the AF contamination of crops, a sensitive and precise detection method for these toxigenic fungi in environments is necessary. We herein developed a novel visual detection method, the dichlorvos-ammonia (DV-AM) method, for identifying AF-producing fungi using DV and AM vapor on agar culture plates, in which DV inhibits the esterase in AF biosynthesis, causing the accumulation of anthraquinone precursors (versiconal hemiacetal acetate and versiconol acetate) of AFs in mycelia on the agar plate, followed by a change in the color of the colonies from light yellow to brilliant purple-red by the AM vapor treatment. We also investigated the appropriate culture conditions to increase the color intensity. It should be noted that other species producing the same precursors of AFs such as Aspergillus nidulans and Aspergillus versicolor could be discriminated from the Aspergillus section Flavi based on the differences of their phenotypes. The DV-AM method was also useful for the isolation of nonaflatoxigenic fungi showing no color change, for screening microorganisms that inhibit the AF production by fungi, and for the characterization of the fungi infecting corn kernels. Thus, the DV-AM method can provide a highly sensitive and visible indicator for the detection of aflatoxigenic fungi.

  6. Biodiversity of Aspergillus species in some important agricultural products.

    PubMed

    Perrone, G; Susca, A; Cozzi, G; Ehrlich, K; Varga, J; Frisvad, J C; Meijer, M; Noonim, P; Mahakarnchanakul, W; Samson, R A

    2007-01-01

    The genus Aspergillus is one of the most important filamentous fungal genera. Aspergillus species are used in the fermentation industry, but they are also responsible of various plant and food secondary rot, with the consequence of possible accumulation of mycotoxins. The aflatoxin producing A. flavus and A. parasiticus, and ochratoxinogenic A. niger, A. ochraceus and A. carbonarius species are frequently encountered in agricultural products. Studies on the biodiversity of toxigenic Aspergillus species is useful to clarify molecular, ecological and biochemical characteristics of the different species in relation to their different adaptation to environmental and geographical conditions, and to their potential toxigenicity. Here we analyzed the biodiversity of ochratoxin producing species occurring on two important crops: grapes and coffee, and the genetic diversity of A. flavus populations occurring in agricultural fields. Altogether nine different black Aspergillus species can be found on grapes which are often difficult to identify with classical methods. The polyphasic approach used in our studies led to the identification of three new species occurring on grapes: A. brasiliensis, A. ibericus, and A. uvarum. Similar studies on the Aspergillus species occurring on coffee beans have evidenced in the last five years that A. carbonarius is an important source of ochratoxin A in coffee. Four new species within the black aspergilli were also identified in coffee beans: A. sclerotioniger, A. lacticoffeatus, A. sclerotiicarbonarius, and A. aculeatinus. The genetic diversity within A. flavus populations has been widely studied in relation to their potential aflatoxigenicity and morphological variants L- and S-strains. Within A. flavus and other Aspergillus species capable of aflatoxin production, considerable diversity is found. We summarise the main recent achievements in the diversity of the aflatoxin gene cluster in A. flavus populations, A. parasiticus and the non

  7. Molecular variation analysis of Aspergillus flavus using polymerase chain reaction-restriction fragment length polymorphism of the internal transcribed spacer rDNA region

    PubMed Central

    Zarrin, Majid; Erfaninejad, Maryam

    2016-01-01

    Aspergillus flavus is the second most common disease-causing species of Aspergillus in humans. The fungus is frequently associated with life-threatening infections in immunocompromised hosts. The primary aim of the present study was to analyze the genetic variability among different isolates of A. flavus using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP). A total of 62 A. flavus isolates were tested in the study. Molecular variability was searched for by analysis of the PCR amplification of the internal transcribed spacer (ITS) regions of ribosomal DNA using restriction enzymes. PCR using primers for ITS1 and ITS4 resulted in a product of ~600 bp. Amplicons were subjected to digestion with restriction endonucleases EcoRI, HaeIII and TaqI. Digestion of the PCR products using these restriction enzymes produced different patterns of fragments among the isolates, with different sizes and numbers of fragments, revealing genetic variability. In conclusion, ITS-RFLP is a useful molecular tool in screening for nucleotide polymorphisms among A. flavus isolates. PMID:27588085

  8. Natural maize phenolic acids for control of aflatoxigenic fungi on maize.

    PubMed

    Nesci, A; Gsponer, N; Etcheverry, M

    2007-06-01

    Natural phytochemicals may be an alternative to synthetic chemicals for controlling fungal growth and mycotoxin production in stored maize. A key to progress in this field is to select the best natural maize phytochemicals to be applied in a storage maize ecosystem. This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 20 to 30 mM and in 5 combinations on Aspergillus flavus Link and A. parasiticus Speare populations and aflatoxin B(1) production. Studies on Aspergillus population and aflatoxin B(1) production were carried out in maize grain in relation to a water activity a(w) of 0.99, 0.97, 0.95, and 0.93. CA and FA at concentrations of 25 to 30 mM, respectively, and CA-FA mixture T9 (25 + 30 mM) were the treatments most effective at inhibiting A. flavus and A. parasiticus population at all a(w) assayed after 11 d of incubation. At all a(w) values, the mixture CA-FA T9 (25 + 30 mM) completely inhibited (100%) aflatoxin B(1) production by both strains at a(w)= 0.99, 0.97, 0.95, and 0.93. Decreased aflatoxin B(1) levels in comparison with the control were observed with mixtures CA-FA T6 (10 + 25 mM), T7 (20 + 20 mM), and T8 (20 + 30 mM) of both strains in the majority of a(w) assayed. The data show that CA and FA could be considered as effective fungitoxicants for A. flavus and A. parasiticus in maize in the a(w) range 0.99 to 0.93. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize.

  9. Behaviour of Aspergillus flavus and Fusarium graminearum on rice as affected by degree of milling, temperature, and relative humidity during storage.

    PubMed

    Choi, Seonyeong; Jun, Hyejung; Bang, Jihyun; Chung, Soo-Hyun; Kim, Yoonsook; Kim, Byeong-Sam; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

    2015-04-01

    We investigated the survival and growth patterns of Aspergillus flavus and Fusarium graminearum, as well as mycotoxin production, on Korean rice as affected by the degree of milling (rough, brown, and white rice) and storage conditions (21 °C/85% relative humidity [RH], 21 °C/97% RH, and 30 °C/85% RH). When rice was stored at 21 °C/85% RH, the population of A. flavus remained constant and aflatoxin was not produced, regardless of the degree of milling. At 21 °C/97% RH and 30 °C/85% RH, the populations of A. flavus increased significantly (P ≤ 0.05) and aflatoxins were produced. The highest population of A. flavus and highest amount of aflatoxin B1 were observed on brown rice stored at 21 °C/97% RH. For F. graminearum, when stored at 85% RH, the populations were reduced to less than a detectable level (5 CFU/g of rice) within 120 days and no deoxynivalenol (DON) was produced, regardless of the degree of milling and storage temperature. However, at 21 °C/97% RH, the population of F. graminearum increased significantly (P ≤ 0.05) and DON was produced on all types of rice. Findings from this study provide insights concerning storage conditions necessary to prevent growth and mycotoxin production by A. flavus and F. graminearum on Korean rice with different degrees of milling.

  10. Perillaldehyde, a Promising Antifungal Agent Used in Food Preservation, Triggers Apoptosis through a Metacaspase-Dependent Pathway in Aspergillus flavus.

    PubMed

    Tian, Jun; Wang, Yanzhen; Lu, Zhaoqun; Sun, Chunhui; Zhang, Man; Zhu, Aihua; Peng, Xue

    2016-10-05

    In the present study, we provide detailed insights into perillaldehyde (PAE)'s mechanisms of action on Aspergillus flavus and offer evidence in favor of the induction of an apoptosis-like phenotype. Specifically, PAE's antifungal mode of action was investigated through the detection of mitochondrial membrane potential (MtΔψ) and phosphatidylserine (PS) exposure, as well as intracellular Ca(2+) level, reactive oxygen species accumulation, and metacaspase activation. This was done by way of fluorometry, measuring DNA fragmentation, and condensation by fluorescent microscopy. Furthermore, we searched for phenotypic changes characteristic of apoptosis by transmission electron microscopy and flow cytometry, determining the amount of cytochrome c released using Western blotting. Results indicated that cultivation of A. flavus in the presence of PAE caused depolarization of MtΔψ, rapid DNA condensation, large-scale DNA fragmentation, and an elevation of intracellular Ca(2+) level. The percentage of early apoptotic cells with exposure of PS were 27.4% and 48.7%, respectively, after 9 h incubations with 0.25 and 0.5 μL/mL of PAE. The percentage of stained cells with activated intracellular metacaspases exposed to PAE at concentrations of 0.25 and 0.5 μL/mL compared with control subjects were increased by 28.4 ± 3.25% and 37.9 ± 4.24%, respectively. The above results has revealed that PAE induces fungal apoptosis through a caspase-dependent mitochondrial pathway. In all, our findings provide a novel mechanism for exploring a possible antifungal agent used in food preservation.

  11. Identification of lipoxygenase (LOX) genes from legumes and their responses in wild type and cultivated peanut upon Aspergillus flavus infection

    PubMed Central

    Song, Hui; Wang, Pengfei; Li, Changsheng; Han, Suoyi; Lopez-Baltazar, Javier; Zhang, Xinyou; Wang, Xingjun

    2016-01-01

    Lipoxygenase (LOX) genes are widely distributed in plants and play crucial roles in resistance to biotic and abiotic stress. Although they have been characterized in various plants, little is known about the evolution of legume LOX genes. In this study, we identified 122 full-length LOX genes in Arachis duranensis, Arachis ipaënsis, Cajanus cajan, Cicer arietinum, Glycine max, Lotus japonicus and Medicago truncatula. In total, 64 orthologous and 36 paralogous genes were identified. The full-length, polycystin-1, lipoxygenase, alpha-toxin (PLAT) and lipoxygenase domain sequences from orthologous and paralogous genes exhibited a signature of purifying selection. However, purifying selection influenced orthologues more than paralogues, indicating greater functional conservation of orthologues than paralogues. Neutrality and effective number of codons plot results showed that natural selection primarily shapes codon usage, except for C. arietinum, L. japonicas and M. truncatula LOX genes. GCG, ACG, UCG, CGG and CCG codons exhibited low relative synonymous codon usage (RSCU) values, while CCA, GGA, GCU, CUU and GUU had high RSCU values, indicating that the latter codons are strongly preferred. LOX expression patterns differed significantly between wild-type peanut and cultivated peanut infected with Aspergillus flavus, which could explain the divergent disease resistance of wild progenitor and cultivars. PMID:27731413

  12. Solid-state fermentation of palm kernel cake with Aspergillus flavus in laterally aerated moving bed bioreactor.

    PubMed

    Wong, Yoke Phooi; Saw, Horng Yuan; Janaun, Jidon; Krishnaiah, Kamatam; Prabhakar, Auti

    2011-05-01

    Solid-state fermentation (SSF) was employed to enhance the nutritive values of palm kernel cake (PKC) for poultry feeding. Aspergillus flavus was isolated from local PKC and utilized to increase the mannose content of PKC via the degradation of β-mannan in PKC; evaluation was done for batch SSF in Erlenmeyer flasks and in a novel laterally aerated moving bed (LAMB) bioreactor. The optimum condition for batch SSF in flasks was 110% initial moisture content, initial pH 6.0, 30 °C, 855 μm particle size, and 120 h of fermentation, yielding 90.91 mg mannose g⁻¹ dry PKC (5.9-fold increase). Batch SSF in the LAMB at the optimum condition yielded 79.61 mg mannose g⁻¹ dry PKC (5.5-fold increase) within just 96 h due to better heat and mass transfer when humidified air flowed radially across the PKC bed. In spite of a compromise of 12% reduction in mannose content when compared with the flasks, the LAMB facilitated good heat and mass transfer, and improved the mannose content of PKC in a shorter fermentation period. These attributes are useful for batch production of fermented PKC feed in an industrial scale.

  13. Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus

    PubMed Central

    El Khoury, Rhoda; Caceres, Isaura; Puel, Olivier; Bailly, Sylviane; Atoui, Ali; Oswald, Isabelle P.; El Khoury, André; Bailly, Jean-Denis

    2017-01-01

    Of all the food-contaminating mycotoxins, aflatoxins, and most notably aflatoxin B1 (AFB1), are found to be the most toxic and economically costly. Green farming is striving to replace fungicides and develop natural preventive strategies to minimize crop contamination by these toxic fungal metabolites. In this study, we demonstrated that an aqueous extract of the medicinal plant Micromeria graeca—known as hyssop—completely inhibits aflatoxin production by Aspergillus flavus without reducing fungal growth. The molecular inhibitory mechanism was explored by analyzing the expression of 61 genes, including 27 aflatoxin biosynthesis cluster genes and 34 secondary metabolism regulatory genes. This analysis revealed a three-fold down-regulation of aflR and aflS encoding the two internal cluster co-activators, resulting in a drastic repression of all aflatoxin biosynthesis genes. Hyssop also targeted fifteen regulatory genes, including veA and mtfA, two major global-regulating transcription factors. The effect of this extract is also linked to a transcriptomic variation of several genes required for the response to oxidative stress such as msnA, srrA, catA, cat2, sod1, mnsod, and stuA. In conclusion, hyssop inhibits AFB1 synthesis at the transcriptomic level. This aqueous extract is a promising natural-based solution to control AFB1 contamination. PMID:28257049

  14. Aspergillus flavus Conidia-derived Carbon/Sulfur Composite as a Cathode Material for High Performance Lithium–Sulfur Battery

    NASA Astrophysics Data System (ADS)

    Xu, Maowen; Jia, Min; Mao, Cuiping; Liu, Sangui; Bao, Shujuan; Jiang, Jian; Liu, Yang; Lu, Zhisong

    2016-01-01

    A novel approach was developed to prepare porous carbon materials with an extremely high surface area of 2459.6 m2g‑1 by using Aspergillus flavus conidia as precursors. The porous carbon serves as a superior cathode material to anchor sulfur due to its uniform and tortuous morphology, enabling high capacity and good cycle lifetime in lithium sulfur-batteries. Under a current rate of 0.2 C, the carbon-sulfur composites with 56.7 wt% sulfur loading deliver an initial capacity of 1625 mAh g‑1, which is almost equal to the theoretical capacity of sulfur. The good performance may be ascribed to excellent electronic networks constructed by the high-surface-area carbon species. Moreover, the semi-closed architecture of derived carbons can effectively retard the polysulfides dissolution during charge/discharge, resulting in a capacity of 940 mAh g‑1 after 120 charge/discharge cycles.

  15. ord1, an oxidoreductase gene responsible for conversion of O-methylsterigmatocystin to aflatoxin in Aspergillus flavus.

    PubMed Central

    Prieto, R; Woloshuk, C P

    1997-01-01

    Among the enzymatic steps in the aflatoxin biosynthetic pathway, the conversion of O-methylsterigmatocystin to aflatoxin has been proposed to be catalyzed by an oxidoreductase. Transformants of Aspergillus flavus 649WAF2 containing a 3.3-kb genomic DNA fragment and the aflatoxin biosynthesis regulatory gene aflR converted exogenously supplied O-methylsterigmatocystin to aflatoxin B1. A gene, ord1, corresponding to a transcript of about 2 kb was identified within the 3.3-kb DNA fragment. The promoter region presented a putative AFLR binding site and a TATA sequence. The nucleotide sequence of the gene revealed an open reading frame encoding a protein of 528 amino acids with a deduced molecular mass of 60.2 kDa. The gene contained six introns and seven exons. Heterologous expression of the ord1 open reading frame under the transcriptional control of the Saccharomyces cerevisiae galactose-inducible gal1 promoter results in the ability to convert O-methylsterigmatocystin to aflatoxin B1. The data indicate that ord1 is sufficient to accomplish the last step of the aflatoxin biosynthetic pathway. A search of various databases for similarity indicated that ord1 encodes a cytochrome P-450-type monooxygenase, and the gene has been assigned to a new P-450 gene family named CYP64. PMID:9143099

  16. Effect of Capsicum carotenoids on growth and aflatoxins production by Aspergillus flavus isolated from paprika and chilli.

    PubMed

    Santos, L; Kasper, R; Sardiñas, N; Marín, S; Sanchis, V; Ramos, A J

    2010-12-01

    The aim of this study was to determine the effect of a carotenoid mixture (Capsantal FS-30-NT), containing capsanthin and capsorubin, on growth and aflatoxins (AF) production of AF-producing Aspergillus flavus isolates. Each isolate, previously isolated from paprika and chilli, was inoculated on Czapek Yeast extract Agar (CYA) medium supplemented with different amounts of capsantal (0-1%) and incubated at 10, 15 and 25 °C during 21 days. Growth rates and lag phases were obtained, and AF production was determined at 7, 14 and 21 days. None of the isolates grew at 10 °C and one isolate (UdLTA 3.193) hardly grew at 15 °C. Capsantal addition had no effect over lag phases and growth rates at 15 °C. At 25 °C capsantal reduced growth rates and increased lag phases. However, the effect of capsantal on AF production was inconclusive, because it depended on temperature or time, and most of the times it was not significant. Low temperature has been a crucial factor in AF production, regardless of the capsantal concentration tested. Industrial storage temperature for paprika and chilli use to be approximately 10 °C, so if this temperature is maintained mould growth and AF production should be prevented.

  17. Use of a Repetitive DNA Probe To Type Clinical and Environmental Isolates of Aspergillus flavus from a Cluster of Cutaneous Infections in a Neonatal Intensive Care Unit

    PubMed Central

    James, Michael J.; Lasker, Brent A.; McNeil, Michael M.; Shelton, Mark; Warnock, David W.; Reiss, Errol

    2000-01-01

    Aspergillus flavus is second to A. fumigatus as a cause of invasive aspergillosis, but no standard method exists for molecular typing of strains from human sources. A repetitive DNA sequence cloned from A. flavus and subcloned into a pUC19 vector, pAF28, was used to type 18 isolates from diverse clinical, environmental, and geographic sources. The restriction fragment length polymorphisms generated with EcoRI- or PstI-digested genomic DNA and probed with digoxigenin-labeled pAF28 revealed complete concordance between patterns. Eighteen distinct fingerprints were observed. The probe was used to investigate two cases of cutaneous A. flavus infection in low-birth-weight infants in a neonatal intensive care unit (NICU). Both infants were transported by the same ambulance and crew to the NICU on the same day. A. flavus strains of the same genotype were isolated from both infants, from a roll of tape used to fasten their umbilical catheters, from a canvas bag used to store the tape in the ambulance, and from the tape tray in the ambulance isolette. These cases highlight the need to consider exposures in critically ill neonates that might occur during their transport to the NICU and for stringent infection control practices. The hybridization profiles of strains from a second cluster of invasive A. flavus infections in two pediatric hematology-oncology patients revealed a genotype common to strains from a definite case patient and a health care worker. A probable case patient was infected with a strain with a genotype different from that of the strain from the definite case patient but highly related to that of an environmental isolate. The high degree of discrimination and reproducibility obtained with the pAF28 probe underscores its utility for typing clinical and environmental isolates of A. flavus. PMID:11015372

  18. Efficacy of a coating composed of chitosan from Mucor circinelloides and carvacrol to control Aspergillus flavus and the quality of cherry tomato fruits

    PubMed Central

    de Souza, Evandro L.; Sales, Camila V.; de Oliveira, Carlos E. V.; Lopes, Laênia A. A.; da Conceição, Maria L.; Berger, Lúcia R. R.; Stamford, Thayza C. M.

    2015-01-01

    Cherry tomato (Lycopersicon esculentum Mill) fruits are susceptible to contamination by Aspergillus flavus, which may cause the development of fruit rot and significant postharvest losses. Currently there are significant drawbacks for the use of synthetic fungicides to control pathogenic fungi in tomato fruits, and it has increased the interest in exploring new alternatives to control the occurrence of fungal infections in these fruits. This study evaluated the efficacy of chitosan (CHI) from Mucor circinelloides in combination with carvacrol (CAR) in inhibiting A. flavus in laboratory media and as a coating on cherry tomato fruits (25°C, 12 days and 12°C, 24 days). During a period of storage, the effect of coatings composed of CHI and CAR on autochthonous microflora, as well as on some quality characteristics of the fruits such as weight loss, color, firmness, soluble solids, and titratable acidity was evaluated. CHI and CAR displayed MIC valuesof 7.5 mg/mL and 10 μL/mL, respectively, against A. flavus. The combined application of CHI (7.5 or 3.75 mg/mL) and CAR (5 or 2.5 μL/mL) strongly inhibited the mycelial growth and spore germination of A. flavus. The coating composed of CHI (3.75 mg/mL) and CAR (2.5 or 1.25 μL/mL) inhibited the growth of A. flavus in artificially contaminated fruits, as well as the native fungal microflora of the fruits stored at room or low temperature. The application of the tested coatings preserved the quality of cherry tomato fruits as measured by some physicochemical attributes. From this, composite coatings containing CHI and CAR offer a promising alternative to control postharvest infection caused by A. flavus or native fungal microflora in fresh cherry tomato fruits without negatively affecting their quality over storage. PMID:26257717

  19. Effect of temperature and water activity on gene expression and aflatoxin biosynthesis in Aspergillus flavus on almond medium.

    PubMed

    Gallo, Antonia; Solfrizzo, Michele; Epifani, Filomena; Panzarini, Giuseppe; Perrone, Giancarlo

    2016-01-18

    Almonds are among the commodities at risk of aflatoxin contamination by Aspergillus flavus. Temperature and water activity are the two key determinants in pre and post-harvest environments influencing both the rate of fungal spoilage and aflatoxin production. Varying the combination of these parameters can completely inhibit or fully activate the biosynthesis of aflatoxin, so it is fundamental to know which combinations can control or be conducive to aflatoxin contamination. Little information is available about the influence of these parameters on aflatoxin production on almonds. The objective of this study was to determine the influence of different combinations of temperature (20 °C, 28 °C, and 37 °C) and water activity (0.90, 0.93, 0.96, 0.99 aw) on growth, aflatoxin B1 (AFB1) production and expression of the two regulatory genes, aflR and aflS, and two structural genes, aflD and aflO, of the aflatoxin biosynthetic cluster in A. flavus grown on an almond medium solidified with agar. Maximum accumulation of fungal biomass and AFB1 production was obtained at 28 °C and 0.96 aw; no fungal growth and AFB1 production were observed at 20 °C at the driest tested conditions (0.90 and 0.93 aw). At 20° and 37 °C AFB1 production was 70-90% lower or completely suppressed, depending on aw. Reverse transcriptase quantitative PCR showed that the two regulatory genes (aflR and aflS) were highly expressed at maximum (28 °C) and minimum (20 °C and 37 °C) AFB1 production. Conversely the two structural genes (aflD and aflO) were highly expressed only at maximum AFB1 production (28 °C and 0.96-0.99 aw). It seems that temperature acts as a key factor influencing aflatoxin production which is strictly correlated to the induction of expression of structural biosynthesis genes (aflD and aflO), but not to that of aflatoxin regulatory genes (aflR and aflS), whose functional products are most likely subordinated to other regulatory processes acting at post-translational level

  20. Biotechnological advances for combating Aspergillus flavus and aflatoxin contamination in crops.

    PubMed

    Bhatnagar-Mathur, Pooja; Sunkara, Sowmini; Bhatnagar-Panwar, Madhurima; Waliyar, Farid; Sharma, Kiran Kumar

    2015-05-01

    Aflatoxins are toxic, carcinogenic, mutagenic, teratogenic and immunosuppressive byproducts of Aspergillus spp. that contaminate a wide range of crops such as maize, peanut, and cotton. Aflatoxin not only affects crop production but renders the produce unfit for consumption and harmful to human and livestock health, with stringent threshold limits of acceptability. In many crops, breeding for resistance is not a reliable option because of the limited availability of genotypes with durable resistance to Aspergillus. Understanding the fungal/crop/environment interactions involved in aflatoxin contamination is therefore essential in designing measures for its prevention and control. For a sustainable solution to aflatoxin contamination, research must be focused on identifying and improving knowledge of host-plant resistance factors to aflatoxin accumulation. Current advances in genetic transformation, proteomics, RNAi technology, and marker-assisted selection offer great potential in minimizing pre-harvest aflatoxin contamination in cultivated crop species. Moreover, developing effective phenotyping strategies for transgenic as well as precision breeding of resistance genes into commercial varieties is critical. While appropriate storage practices can generally minimize post-harvest aflatoxin contamination in crops, the use of biotechnology to interrupt the probability of pre-harvest infection and contamination has the potential to provide sustainable solution.

  1. Genome-Wide Transcriptome Analysis of Cotton (Gossypium hirsutum L.) Identifies Candidate Gene Signatures in Response to Aflatoxin Producing Fungus Aspergillus flavus.

    PubMed

    Bedre, Renesh; Rajasekaran, Kanniah; Mangu, Venkata Ramanarao; Sanchez Timm, Luis Eduardo; Bhatnagar, Deepak; Baisakh, Niranjan

    2015-01-01

    Aflatoxins are toxic and potent carcinogenic metabolites produced from the fungi Aspergillus flavus and A. parasiticus. Aflatoxins can contaminate cottonseed under conducive preharvest and postharvest conditions. United States federal regulations restrict the use of aflatoxin contaminated cottonseed at >20 ppb for animal feed. Several strategies have been proposed for controlling aflatoxin contamination, and much success has been achieved by the application of an atoxigenic strain of A. flavus in cotton, peanut and maize fields. Development of cultivars resistant to aflatoxin through overexpression of resistance associated genes and/or knocking down aflatoxin biosynthesis of A. flavus will be an effective strategy for controlling aflatoxin contamination in cotton. In this study, genome-wide transcriptome profiling was performed to identify differentially expressed genes in response to infection with both toxigenic and atoxigenic strains of A. flavus on cotton (Gossypium hirsutum L.) pericarp and seed. The genes involved in antifungal response, oxidative burst, transcription factors, defense signaling pathways and stress response were highly differentially expressed in pericarp and seed tissues in response to A. flavus infection. The cell-wall modifying genes and genes involved in the production of antimicrobial substances were more active in pericarp as compared to seed. The genes involved in auxin and cytokinin signaling were also induced. Most of the genes involved in defense response in cotton were highly induced in pericarp than in seed. The global gene expression analysis in response to fungal invasion in cotton will serve as a source for identifying biomarkers for breeding, potential candidate genes for transgenic manipulation, and will help in understanding complex plant-fungal interaction for future downstream research.

  2. In vitro effect of some fungicides on growth and aflatoxins production by Aspergillus flavus isolated from Capsicum powder.

    PubMed

    Santos, L; Marin, S; Sanchis, V; Ramos, A J

    2011-01-01

    The aim of this study was to determine the effect of some pre-harvest fungicides on growth and aflatoxin (AF) production of three Aspergillus flavus strains found in Capsicum powder. Each isolate, previously isolated from paprika, chilli and smoked paprika, was inoculated on yeast extract sucrose agar and on a 3% paprika extract agar medium supplemented with different fungicides and incubated at 20 and 30°C during 7 days. Growth measurements were obtained on days 3, 5 and 7, and the AF production was determined on day 7. The significance of the effects of the factors (strain, medium, temperature, time and fungicides) and their interaction over colony diameter and AF production was determined. Temperature constrained the effectiveness of fungicides in reducing growth, the fungicides being most effective at 20°C. The efficacy of the fungicides over AF production depended on the medium used and temperature. The most effective fungicides in inhibiting growth and AF production, regardless of the strain tested or applied conditions, were tebuconazole 25% and mancozeb 80% applied at a concentration of 0.75 and 3.5 g l(-1), respectively. Care should thus be taken in the choice of a suitable fungicide because their effectiveness may depend on intra-specific variation and temperature. Moreover, it is necessary to take into account that the most efficient fungicide in reducing growth is not always the best choice for pre-harvest treatments because it may promote AF production. Thus, the best fungicide is the one that can simultaneous prevent growth and AF production.

  3. A study on trypsin, Aspergillus flavus and Bacillus sp. protease inhibitory activity in Cassia tora (L.) syn Senna tora (L.) Roxb. seed extract

    PubMed Central

    2011-01-01

    Background Proteases play an important role in virulence of many human, plant and insect pathogens. The proteinaceous protease inhibitors of plant origin have been reported widely from many plant species. The inhibitors may potentially be used for multiple therapeutic applications in viral, bacterial, fungal diseases and physiological disorders. In traditional Indian medicine system, Cassia tora (Senna tora) is reportedly effective in treatment of skin and gastrointestinal disorders. The present study explores the protease inhibitory activity of the above plant seeds against trypsin, Aspergillus flavus and Bacillus sp. proteases. Methods The crushed seeds of Cassia tora were washed thoroughly with acetone and hexane for depigmentation and defatting. The proteins were fractionated by ammonium sulphate (0-30, 30-60, 60-90%) followed by dialysis and size exclusion chromatography (SEC). The inhibitory potential of crude seed extract and most active dialyzed fraction against trypsin and proteases was established by spot test using unprocessed x-ray film and casein digestion methods, respectively. Electrophoretic analysis of most active fraction (30-60%) and SEC elutes were carried employing Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Gelatin SDS-PAGE. Inhibition of fungal spore germination was studied in the presence of dialyzed active inhibitor fraction. Standard deviation (SD) and ANOVA were employed as statistical tools. Results The crude seeds' extract displayed strong antitryptic, bacterial and fungal protease inhibitory activity on x-ray film. The seed protein fraction 30-60% was found most active for trypsin inhibition in caseinolytic assay (P < 0.001). The inhibition of caseinolytic activity of the proteases increased with increasing ratio of seed extract. The residual activity of trypsin, Aspergillus flavus and Bacillus sp. proteases remained only 4, 7 and 3.1%, respectively when proteases were incubated with 3 mg ml-1 seed protein

  4. [THE EFFECT OF METAL IONES AND SPECIFIC CHEMICAL REAGENTS ON THE ACTIVITY OF ASPERGILLUS FLAVUS VAR. ORYZAE AND BACILLUS SUBTILIS α-AMYLASES].

    PubMed

    Avdiyuk, K V; Varbanets, L D

    2015-01-01

    The effect of cations and anions on the activity of Aspergillus flavus var. oryzae and Bacillus subtilis α-amylases showed that the tested enzymes are sensitive to most of cations and resistant to anions. The most significant inhibitory effects on the activity of A. flavus var. oryzae α-amylase have been demonstrated by Al3+ and Fe3+ ions, while on the activity of B. subtilis α-amylase - Hg2+, Cu2+ and Fe3+ ions. Inactivation of A. flavus var. oryzae and B. subtilis α-amylases in the presence of EGTA is indicated on the presence within their structure of metal ions. An important role in the enzymatic catalysis of both enzymes play carboxyl groups as evidenced by their inhibition of 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide. Inhibition of B. subtilis α-amylase by p-chloromercuribenzoate, N-ethylmaleimide and sodium sulfite is indicated on the probable involvement of the sulfhydryl groups in the functioning of the enzyme. Unlike most studied glycosidases the tested enzymes do not contain histidine imidazole group in the active center.

  5. Effects of temperature, water activity and incubation time on fungal growth and aflatoxin B1 production by toxinogenic Aspergillus flavus isolates on sorghum seeds.

    PubMed

    Lahouar, Amani; Marin, Sonia; Crespo-Sempere, Ana; Saïd, Salem; Sanchis, Vicente

    2016-01-01

    Sorghum, which is consumed in Tunisia as human food, suffers from severe colonization by several toxigenic fungi and contamination by mycotoxins. The Tunisian climate is characterized by high temperature and humidity that stimulates mold proliferation and mycotoxin accumulation in foodstuffs. This study investigated the effects of temperature (15, 25 and 37°C), water activity (aw, between 0.85 and 0.99) and incubation time (7, 14, 21 and 28 d) on fungal growth and aflatoxin B1 (AFB1) production by three Aspergillus flavus isolates (8, 10 and 14) inoculated on sorghum grains. The Baranyi model was applied to identify the limits of growth and mycotoxin production. Maximum diameter growth rates were observed at 0.99 a(w) at 37°C for two of the isolates. The minimum aw needed for mycelial growth was 0.91 at 25 and 37°C. At 15°C, only isolate 8 grew at 0.99 a(w). Aflatoxin B1 accumulation could be avoided by storing sorghum at low water activity levels (≤0.91 a(w)). Aflatoxin production was not observed at 15°C. This is the first work on the effects of water activity and temperature on A. flavus growth and AFB1 production by A. flavus isolates on sorghum grains.

  6. Efficacy of Mentha spicata essential oil in suppression of Aspergillus flavus and aflatoxin contamination in chickpea with particular emphasis to mode of antifungal action.

    PubMed

    Kedia, Akash; Dwivedy, Abhishek Kumar; Jha, Dhruva Kumar; Dubey, Nawal Kishore

    2016-05-01

    The present study reports in vivo antifungal and antiaflatoxigenic efficacy of Mentha spicata essential oil (EO) against toxigenic Aspergillus flavus strain LHP(C)-D6 in chickpea food system up to 12 months of storage. In addition, the mode of antifungal action of EO was also determined to understand the mechanism of fungal growth inhibition. The in vivo study with different concentrations of M. spicata EO showed dose-dependent decrease in fungal colony count as well as aflatoxin B1 concentration. The EO caused >50% protection in inoculated sets and >70% protection in uninoculated sets of chickpea food system against A. flavus at 1.0 μL mL(-1) air concentration. However, at the same concentration, EO caused 100% inhibition to aflatoxin B1 production in both sets when analyzed through high-performance liquid chromatography (HPLC). The antifungal target of EO in fumigated cells of A. flavus was found to be the plasma membrane when analyzed through electron microscopic observations and ions leakage test. The EO fumigated chickpea seeds showed 100% seed germination and seedling growth after 12 months of storage. Based on these observations, M. spicata EO can be recommended as plant-based preservative for safe protection of food commodities during storage conditions against fungal and most importantly mycotoxin contaminations.

  7. The major volatile compound 2-phenylethanol from the biocontrol yeast, Pichia anomala, inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus.

    PubMed

    Hua, Sui Sheng T; Beck, John J; Sarreal, Siov Bouy L; Gee, Wai

    2014-05-01

    Aspergillus flavus is a ubiquitous saprophyte that is able to produce the most potent natural carcinogenic compound known as aflatoxin B1 (AFB1). This toxin frequently contaminates crops including corn, cotton, peanuts, and tree nuts causing substantial economic loss worldwide. Consequently, more than 100 countries have strict regulations limiting AFB1 in foodstuffs and feedstuffs. Plants and microbes are able to produce volatile compounds that act as a defense mechanism against other organisms. Pichia anomala strain WRL-076 is a biocontrol yeast currently being tested to reduce AF contamination of tree nuts in California. We used the SPME-GC/MS analysis and identified the major volatile compound produced by this strain to be 2-phenylethanol (2-PE). It inhibited spore germination and AF production of A. flavus. Inhibition of AF formation by 2-PE was correlated with significant down regulation of clustering AF biosynthesis genes as evidenced by several to greater than 10,000-fold decrease in gene expression. In a time-course analysis we found that 2-PE also altered the expression patterns of chromatin modifying genes, MYST1, MYST2, MYST3, gcn5, hdaA and rpdA. The biocontrol capacity of P. anomala can be attributed to the production of 2-PE, which affects spore germination, growth, toxin production, and gene expression in A. flavus.

  8. Suppression of Aflatoxin Biosynthesis in Aspergillus flavus by 2-Phenylethanol Is Associated with Stimulated Growth and Decreased Degradation of Branched-Chain Amino Acids.

    PubMed

    Chang, Perng-Kuang; Hua, Sui Sheng T; Sarreal, Siov Bouy L; Li, Robert W

    2015-09-24

    The saprophytic soil fungus Aspergillus flavus infects crops and produces aflatoxin. Pichia anomala, which is a biocontrol yeast and produces the major volatile 2-phenylethanol (2-PE), is able to reduce growth of A. flavus and aflatoxin production when applied onto pistachio trees. High levels of 2-PE are lethal to A. flavus and other fungi. However, at low levels, the underlying mechanism of 2-PE to inhibit aflatoxin production remains unclear. In this study, we characterized the temporal transcriptome response of A. flavus to 2-PE at a subinhibitory level (1 μL/mL) using RNA-Seq technology and bioinformatics tools. The treatment during the entire 72 h experimental period resulted in 131 of the total A. flavus 13,485 genes to be significantly impacted, of which 82 genes exhibited decreased expression. They included those encoding conidiation proteins and involved in cyclopiazonic acid biosynthesis. All genes in the aflatoxin gene cluster were also significantly decreased during the first 48 h treatment. Gene Ontology (GO) analyses showed that biological processes with GO terms related to catabolism of propionate and branched-chain amino acids (valine, leucine and isoleucine) were significantly enriched in the down-regulated gene group, while those associated with ribosome biogenesis, translation, and biosynthesis of α-amino acids OPEN ACCESS Toxins 2015, 7 3888 were over-represented among the up-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that metabolic pathways negatively impacted among the down-regulated genes parallel to those active at 30 °C, a condition conducive to aflatoxin biosynthesis. In contrast, metabolic pathways positively related to the up-regulated gene group resembled those at 37 °C, which favors rapid fungal growth and is inhibitory to aflatoxin biosynthesis. The results showed that 2-PE at a low level stimulated active growth of A. flavus but concomitantly rendered decreased activities in

  9. Functional characterization of a veA-dependent polyketide synthase gene in Aspergillus flavus necessary for the synthesis of asparasone, a sclerotium-specific pigment.

    PubMed

    Cary, Jeffrey W; Harris-Coward, Pamela Y; Ehrlich, Kenneth C; Di Mavungu, José Diana; Malysheva, Svetlana V; De Saeger, Sarah; Dowd, Patrick F; Shantappa, Sourabha; Martens, Stacey L; Calvo, Ana M

    2014-03-01

    The filamentous fungus, Aspergillus flavus, produces the toxic and carcinogenic, polyketide synthase (PKS)-derived family of secondary metabolites termed aflatoxins. While analysis of the A. flavus genome has identified many other PKSs capable of producing secondary metabolites, to date, only a few other metabolites have been identified. In the process of studying how the developmental regulator, VeA, affects A. flavus secondary metabolism we discovered that mutation of veA caused a dramatic down-regulation of transcription of a polyketide synthase gene belonging to cluster 27 and the loss of the ability of the fungi to produce sclerotia. Inactivation of the cluster 27 pks (pks27) resulted in formation of greyish-yellow sclerotia rather than the dark brown sclerotia normally produced by A. flavus while conidial pigmentation was unaffected. One metabolite produced by Pks27 was identified by thin layer chromatography and mass spectral analysis as the known anthraquinone, asparasone A. Sclerotia produced by pks27 mutants were significantly less resistant to insect predation than were the sclerotia produced by the wild-type and more susceptible to the deleterious effects of ultraviolet light and heat. Normal sclerotia were previously thought to be resistant to damage because of a process of melanization similar to that known for pigmentation of conidia. Our results show that the dark brown pigments in sclerotia derive from anthraquinones produced by Pks27 rather than from the typical tetrahydronapthalene melanin production pathway. To our knowledge this is the first report on the genes involved in the biosynthesis of pigments important for sclerotial survival.

  10. Inhibitory Effect of Cinnamaldehyde, Citral, and Eugenol on Aflatoxin Biosynthetic Gene Expression and Aflatoxin B1 Biosynthesis in Aspergillus flavus.

    PubMed

    Liang, Dandan; Xing, Fuguo; Selvaraj, Jonathan Nimal; Liu, Xiao; Wang, Limin; Hua, Huijuan; Zhou, Lu; Zhao, Yueju; Wang, Yan; Liu, Yang

    2015-12-01

    In order to reveal the inhibitory effects of cinnamaldehyde, citral, and eugenol on aflatoxin biosynthesis, the expression levels of 5 key aflatoxin biosynthetic genes were evaluated by real-time PCR. Aspergillus flavus growth and AFB1 production were completely inhibited by 0.80 mmol/L of cinnamaldehyde and 2.80 mmol/L of citral. However, at lower concentration, cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L) significantly reduced AFB1 production with inhibition rate of 68.9%, 95.4%, and 41.8%, respectively, while no effect on fungal growth. Real-time PCR showed that the expressions of aflR, aflT, aflD, aflM, and aflP were down-regulated by cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L). In the presence of cinnamaldehyde, AflM was highly down-regulated (average of 5963 folds), followed by aflP, aflR, aflD, and aflT with the average folds of 55, 18, 6.5, and 5.8, respectively. With 0.80 mmol/L of eugenol, aflP was highly down-regulated (average of 2061-folds), followed by aflM, aflR, aflD, and aflT with average of 138-, 15-, 5.2-, and 4.8-folds reduction, respectively. With 0.56 mmol/L of citral, aflT was completely inhibited, followed by aflM, aflP, aflR, and aflD with average of 257-, 29-, 3.5-, and 2.5-folds reduction, respectively. These results suggest that the reduction in AFB1 production by cinnamaldehyde, eugenol, and citral at low concentration may be due to the down-regulations of the transcription level of aflatoxin biosynthetic genes. Cinnamaldehyde and eugenol may be employed successfully as a good candidate in controlling of toxigenic fungi and subsequently contamination with aflatoxins in practice.

  11. Bioprocess and biotecnology: effect of xylanase from Aspergillus niger and Aspergillus flavus on pulp biobleaching and enzyme production using agroindustrial residues as substract.

    PubMed

    de Alencar Guimaraes, Nelciele Cavalieri; Sorgatto, Michele; Peixoto-Nogueira, Simone de Carvalho; Betini, Jorge Henrique Almeida; Zanoelo, Fabiana Fonseca; Marques, Maria Rita; de Moraes Polizeli, Maria de Lourdes Teixeira; Giannesi, Giovana C

    2013-01-01

    This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50°C, the xylanase of A. niger retained over 85% activity with 2 h of incubation, and A. flavus had a half-life of more than 75 minutes. At 55°C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45 minutes. The xylanase activity of A. niger and A. flavus were somehow protected in the presence of glycerol 5% when compared to the control (without additives). On the biobleaching assay it was observed that the xylanase from A. flavus was more effective in comparison to A. niger. The kappa efficiency corresponded to 36.32 and 25.93, respectively. That is important to emphasize that the cellulase activity was either analyzed and significant levels were not detected, which explain why the viscosity was not significantly modified.

  12. Development of a PCR protocol to detect aflatoxigenic molds in food products.

    PubMed

    Luque, M Isabel; Rodríguez, Alicia; Andrade, María J; Martín, Alberto; Córdoba, Juan J

    2012-01-01

    Aflatoxins are secondary metabolites produced mainly by Aspergillus species growing in foodstuffs. Because aflatoxins have important health effects, the detection of early contamination of foods by aflatoxigenic molds should be useful. In the present work, a reliable conventional PCR method for detecting aflatoxigenic molds of various species was developed. Fifty-six aflatoxigenic and nonaflatoxigenic strains commonly reported in foodstuffs were tested. Aflatoxin production was first confirmed by micellar electrokinetic capillary electrophoresis or/and high-pressure liquid chromatography-mass spectrometry. Based on the conserved regions of the O-methyltransferase gene (omt-1) involved in the aflatoxin biosynthetic pathway, six primer pairs were designed. With only the designed primer pair AFF1-AFR3, the expected PCR product (381 bp) was obtained in all of the tested aflatoxigenic strains of various species and genera. Amplification products were not obtained with this primer pair for any of the nonaflatoxigenic reference molds. However, an amplicon of 453 bp was obtained for all aflatoxigenic and nonaflatoxigenic mold reference strains with a PCR protocol based on the constitutive fungal β-tubulin gene, which was used as a positive fungal control. The PCR protocol based on omt-1 detected as little as 15 pg of DNA from aflatoxigenic molds and 10(2) to 10(3) CFU/g in contaminated food samples. This PCR protocol should be used as a routine technique to detect aflatoxigenic molds in foods.

  13. Responses of Aspergillus flavus to Oxidative Stress Are Related to Fungal Development Regulator, Antioxidant Enzyme, and Secondary Metabolite Biosynthetic Gene Expression

    PubMed Central

    Fountain, Jake C.; Bajaj, Prasad; Nayak, Spurthi N.; Yang, Liming; Pandey, Manish K.; Kumar, Vinay; Jayale, Ashwin S.; Chitikineni, Anu; Lee, Robert D.; Kemerait, Robert C.; Varshney, Rajeev K.; Guo, Baozhu

    2016-01-01

    The infection of maize and peanut with Aspergillus flavus and subsequent contamination with aflatoxin pose a threat to global food safety and human health, and is exacerbated by drought stress. Drought stress-responding compounds such as reactive oxygen species (ROS) are associated with fungal stress responsive signaling and secondary metabolite production, and can stimulate the production of aflatoxin by A. flavus in vitro. These secondary metabolites have been shown to possess diverse functions in soil-borne fungi including antibiosis, competitive inhibition of other microbes, and abiotic stress alleviation. Previously, we observed that isolates of A. flavus showed differences in oxidative stress tolerance which correlated with their aflatoxin production capabilities. In order to better understand these isolate-specific oxidative stress responses, we examined the transcriptional responses of field isolates of A. flavus with varying levels of aflatoxin production (NRRL3357, AF13, and Tox4) to H2O2-induced oxidative stress using an RNA sequencing approach. These isolates were cultured in an aflatoxin-production conducive medium amended with various levels of H2O2. Whole transcriptomes were sequenced using an Illumina HiSeq platform with an average of 40.43 million filtered paired-end reads generated for each sample. The obtained transcriptomes were then used for differential expression, gene ontology, pathway, and co-expression analyses. Isolates which produced higher levels of aflatoxin tended to exhibit fewer differentially expressed genes than isolates with lower levels of production. Genes found to be differentially expressed in response to increasing oxidative stress included antioxidant enzymes, primary metabolism components, antibiosis-related genes, and secondary metabolite biosynthetic components specifically for aflatoxin, aflatrem, and kojic acid. The expression of fungal development-related genes including aminobenzoate degradation genes and conidiation

  14. Susceptibility of strawberries, blackberries, and cherries to Aspergillus mold growth and aflatoxin production.

    PubMed

    Llewellyn, G C; Eadie, T; Dashek, W V

    1982-05-01

    The susceptibility of blackberries, cherries, and strawberries to Aspergillus growth and aflatoxin production has been examined. Three aflatoxigenic isolates of Aspergillus, A. flavus ATCC 15548 and NRRL 3251 as well as A. parasiticus NRRL 2999, were cultured on homogenates of the fruits for 14 days at 28 +/- 2 degrees C. Percent mycelial growth and spore infestation were determined each day with a calibrated grid. At day 14 each culture was frozen at -5 degrees C until aflatoxins were extracted with methylene chloride and water. Aflatoxins were separated by thin layer chromatography (TLC) with benzene-methanol-acetic acid (90 + 5 + 5). This extraction and solvent system provided satisfactory separations of the aflatoxins and was free of background interference on the TLC plates. Although all fruits served as substrates for both Aspergillus growth and aflatoxin production, cherries appeared to be a more favorable substrate than did blackberries, and the latter was more favorable than strawberries. Whereas A. flavus produced both B1 and G1 on all substrates, it yielded B2 and G2 only on cherries. Although A. parasiticus NRRL 2999 synthesized B1, B2, G1, and G2 on both blackberries and cherries, no aflatoxins were detected on strawberries. In contrast, A. flavus NRRL 3251 failed to produce detectable levels of aflatoxin on any substrate. All substrates supported both mycelial growth and subsequent sporulation with cherries greater than blackberries greater than strawberries.

  15. Characterization of Aspergillus species on Brazil nut from the Brazilian Amazonian region and development of a PCR assay for identification at the genus level

    PubMed Central

    2014-01-01

    Background Brazil nut is a protein-rich extractivist tree crop in the Amazon region. Fungal contamination of shells and kernel material frequently includes the presence of aflatoxigenic Aspergillus species from the section Flavi. Aflatoxins are polyketide secondary metabolites, which are hepatotoxic carcinogens in mammals. The objectives of this study were to identify Aspergillus species occurring on Brazil nut grown in different states in the Brazilian Amazon region and develop a specific PCR method for collective identification of member species of the genus Aspergillus. Results Polyphasic identification of 137 Aspergillus strains isolated from Brazil nut shell material from cooperatives across the Brazilian Amazon states of Acre, Amapá and Amazonas revealed five species, with Aspergillus section Flavi species A. nomius and A. flavus the most abundant. PCR primers ASP_GEN_MTSSU_F1 and ASP_GEN_MTSSU_R1 were designed for the genus Aspergillus, targeting a portion of the mitochondrial small subunit ribosomal RNA gene. Primer specificity was validated through both electronic PCR against target gene sequences at Genbank and in PCR reactions against DNA from Aspergillus species and other fungal genera common on Brazil nut. Collective differentiation of the observed section Flavi species A. flavus, A. nomius and A. tamarii from other Aspergillus species was possible on the basis of RFLP polymorphism. Conclusions Given the abundance of Aspergillus section Flavi species A. nomius and A. flavus observed on Brazil nut, and associated risk of mycotoxin accumulation, simple identification methods for such mycotoxigenic species are of importance for Hazard Analysis Critical Control Point system implementation. The assay for the genus Aspergillus represents progress towards specific PCR identification and detection of mycotoxigenic species. PMID:24885088

  16. Identification and Quantification of a Toxigenic and Non-Toxigenic Aspergillus flavus Strain in Contaminated Maize Using Quantitative Real-Time PCR

    PubMed Central

    Mylroie, J. Erik; Ozkan, Seval; Shivaji, Renuka; Windham, Gary L.; Alpe, Michael N.; Williams, W. Paul

    2016-01-01

    Aflatoxins, which are produced by Aspergillus flavus, are toxic to humans, livestock, and pets. The value of maize (Zea mays) grain is markedly reduced when contaminated with aflatoxin. Plant resistance and biological control using non-toxin producing strains are considered effective strategies for reducing aflatoxin accumulation in maize grain. Distinguishing between the toxin and non-toxin producing strains is important in determining the effectiveness of bio-control strategies and understanding inter-strain interactions. Using polymorphisms found in the fungal rRNA intergenic spacer region (IGS) between a toxigenic strain of A. flavus (NRRL 3357) and the non-toxigenic strain used in the biological control agent Afla-Guard® (NRRL 21882), we developed a set of primers that allows for the identification and quantification of the two strains using quantitative PCR. This primer set has been used to screen maize grain that was inoculated with the two strains individually and co-inoculated with both strains, and it has been shown to be effective in both the identification and quantification of both strains. Screening of co-inoculated ears from multiple resistant and susceptible genotypic crosses revealed no significant differences in fungal biomass accumulation of either strain in the field tests from 2010 and 2011 when compared across the means of all genotypes. Only one genotype/year combination showed significant differences in strain accumulation. Aflatoxin accumulation analysis showed that, as expected, genotypes inoculated with the toxigenic strain accumulated more aflatoxin than when co-inoculated with both strains or inoculated with only the non-toxigenic strain. Furthermore, accumulation of toxigenic fungal mass was significantly correlated with aflatoxin accumulation while non-toxigenic fungal accumulation was not. This primer set will allow researchers to better determine how the two fungal strains compete on the maize ear and investigate the interaction

  17. An industry perspective on the use of "atoxigenic" strains of Aspergillus flavus as biological control agents and the significance of cyclopiazonic acid.

    PubMed

    King, Eileen D; Bobby Bassi, Albeit B; Ross, David C; Druebbisch, Bernd

    2011-08-01

    Several nonaflatoxigenic strains of Aspergillus flavus have been registered in the United States to reduce aflatoxin accumulation in maize and other crops, but there may be unintended negative consequences if these strains produce cyclopiazonic acid (CPA). AF36, a nonaflatoxigenic, CPA-producing strain has been shown to produce CPA in treated maize and peanuts. Alternative strains, including Afla-Guard® brand biocontrol agent and K49, do not produce CPA and can reduce both aflatoxin and CPA in treated crops. Chronic toxicity of CPA has not been studied, and recent animal studies show significant harmful effects from short-term exposure to CPA at low doses. Grower and industry confidence in this approach must be preserved through transparency.

  18. Efficacy of the combined application of chitosan and Locust Bean Gum with different citrus essential oils to control postharvest spoilage caused by Aspergillus flavus in dates.

    PubMed

    Aloui, Hajer; Khwaldia, Khaoula; Licciardello, Fabio; Mazzaglia, Agata; Muratore, Giuseppe; Hamdi, Moktar; Restuccia, Cristina

    2014-01-17

    This study reports the efficacy of the combined application of chitosan (CH) and Locust Bean Gum (LBG) in combination with different citrus essential oils (EOs) to inhibit Aspergillus flavus in vitro and on artificially infected dates for a storage period of 12 days. The effect of these treatments on the fruits' sensory characteristics was evaluated to verify the complete absence of off-odours and off-flavours. Bergamot EO was the most effective in reducing mycelial growth, followed by bitter orange EO. Both bergamot and bitter orange oils significantly reduced conidial germination and a complete inhibition was obtained at concentrations higher than 2%. The mixtures based on CH-2% (v/v) bergamot EO or CH-2% (v/v) bitter orange EO proved to be the most effective coatings to reduce conidial germination resulting in an 87-90% inhibition compared with the control. In fruit decay assays coatings based on CH incorporating citrus oils were able to reduce fungal decay in the range of 52-62% at day 12. The study results and the complete absence of off-flavours and off-odours demonstrate the potential of CH coatings carrying citrus EOs at sub-inhibitory concentrations to control postharvest growth of A. flavus in dates.

  19. Occurrence of aflatoxins in mahua (Madhuca indica Gmel.) seeds: synergistic effect of plant extracts on inhibition of Aspergillus flavus growth and aflatoxin production.

    PubMed

    Sidhu, O P; Chandra, Harish; Behl, H M

    2009-04-01

    Occurrence of aflatoxin in Madhuca indica Gmel. seeds was determined by competitive ELISA. Eighty percent of mahua seed samples were found to be contaminated with aflatoxin. Total aflatoxin content ranged from 115.35 to 400.54ppb whereas the concentration of AFB(1) was in the range of 86.43 to 382.45ppb. Mahua oil was extracted by cold press expeller and analysed for contamination of aflatoxin in both the oil and cake samples. Total aflatoxin and aflatoxin B(1) were 220.66 and 201.57ppb in oil as compared to that in cake samples where it was 87.55 and 74.35ppb, respectively. Various individual and combined plant extracts were evaluated for their efficacy against growth of Aspergillus flavus and aflatoxin production in vitro. Combination of botanicals were found to be more effective in controlling fungal growth and aflatoxin production than individual extracts. Results of the present study suggests that synergistic effect of plant extracts can be used for control of fungal growth and aflatoxin production. These natural plant products may successfully replace synthetic chemicals and provide an alternative method to protect mahua as well as other agricultural commodities of nutritional significance from toxigenic fungi such as A. flavus and aflatoxin production.

  20. Biosorption characteristics of Aspergillus flavus biomass for removal of Pb(II) and Cu(II) ions from an aqueous solution.

    PubMed

    Akar, Tamer; Tunali, Sibel

    2006-10-01

    The Pb(II) and Cu(II) biosorption characteristics of Aspergillus flavus fungal biomass were examined as a function of initial pH, contact time and initial metal ion concentration. Heat inactivated (killed) biomass was used in the determination of optimum conditions before investigating the performance of pretreated biosorbent. The maximum biosorption values were found to be 13.46 +/- 0.99 mg/g for Pb(II) and 10.82 +/- 1.46 mg/g for Cu(II) at pH 5.0 +/- 0.1 with an equilibrium time of 2 h. Detergent, sodium hydroxide and dimethyl sulfoxide pretreatments enhanced the biosorption capacity of biomass in comparison with the heat inactivated biomass. The biosorption data obtained under the optimum conditions were well described by the Freundlich isotherm model. Competitive biosorption of Pb(II) and Cu(II) ions was also investigated to determine the selectivity of the biomass. The results indicated that A. flavus is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution.

  1. Laetiporus sulphureus, edible mushroom from Serbia: investigation on volatile compounds, in vitro antimicrobial activity and in situ control of Aspergillus flavus in tomato paste.

    PubMed

    Petrović, Jovana; Glamočlija, Jasmina; Stojković, Dejan S; Ćirić, Ana; Nikolić, Miloš; Bukvički, Danka; Guerzoni, Maria Elisabetta; Soković, Marina D

    2013-09-01

    The volatile compounds of fruiting bodies of wild Laetiporus sulphureus (Bull.) Murrill, growing on willow trees from Serbia, were isolated and extracted using methanol, acetone and dichloromethane and investigated by GC/MS-SPME. A total of 56 components were identified in the extracts. Hydrocarbons predominated (76.90%, 77.20%, and 43.10%) in dichloromethane, acetone and methanol extracts, respectively. Fatty acids, esters and sesquiterpenes were present in amounts equal or lower than 2.00%. Ketones were represented with moderate amount with the exception of methanol extract where it reached as much as 28.90% of the total investigated compounds. Extracts were also tested for antimicrobial activity with and without the addition of food additive - potassium disulfite in vitro against eight bacterial and eight fungal species, and in situ in tomato paste against Aspergillus flavus. All the tested extracts showed good antimicrobial activity, but methanol extract with addition of E224 showed the best antimicrobial activity in vitro. In situ results indicate complete inhibition of A. flavus growth in tomato paste after 15 days of the treatment. This study is the first report on volatile composition of L. sulphureus growing wild in Serbia. We describe for the first time the application of its extract as antifungal food preservative.

  2. In vitro experimental environments lacking or containing soil disparately affect competition experiments of Aspergillus flavus and co-occurring fungi in maize grains.

    PubMed

    Falade, Titilayo D O; Syed Mohdhamdan, Sharifah H; Sultanbawa, Yasmina; Fletcher, Mary T; Harvey, Jagger J W; Chaliha, Mridusmita; Fox, Glen P

    2016-07-01

    In vitro experimental environments are used to study interactions between microorganisms, and to predict dynamics in natural ecosystems. This study highlights that experimental in vitro environments should be selected to match closely the natural environment of interest during in vitro studies to strengthen extrapolations about aflatoxin production by Aspergillus and competing organisms. Fungal competition and aflatoxin accumulation were studied in soil, cotton wool or tube (water-only) environments, for Aspergillus flavus competition with Penicillium purpurogenum, Fusarium oxysporum or Sarocladium zeae within maize grains. Inoculated grains were incubated in each environment at two temperature regimes (25 and 30°C). Competition experiments showed interaction between the main effects of aflatoxin accumulation and the environment at 25°C, but not so at 30°C. However, competition experiments showed fungal populations were always interacting with their environments. Fungal survival differed after the 72-h incubation in different experimental environments. Whereas all fungi incubated within the soil environment survived, in the cotton wool environment none of the competitors of A. flavus survived at 30°C. With aflatoxin accumulation, F. oxysporum was the only fungus able to interdict aflatoxin production at both temperatures. This occurred only in the soil environment and fumonisins accumulated instead. Smallholder farmers in developing countries face serious mycotoxin contamination of their grains, and soil is a natural reservoir for the associated fungal propagules, and a drying and storage surface for grains on these farms. Studying fungal dynamics in the soil environment and other environments in vitro can provide insights into aflatoxin accumulation post-harvest.

  3. Genetic Analysis of the Aspergillus flavus Vegetative Compatibility Group to Which a Biological Control Agent That Limits Aflatoxin Contamination in U.S. Crops Belongs.

    PubMed

    Grubisha, Lisa C; Cotty, Peter J

    2015-09-01

    Some filamentous fungi in Aspergillus section Flavi produce carcinogenic secondary compounds called aflatoxins. Aflatoxin contamination is routinely managed in commercial agriculture with strains of Aspergillus flavus that do not produce aflatoxins. These non-aflatoxin-producing strains competitively exclude aflatoxin producers and reshape fungal communities so that strains with the aflatoxin-producing phenotype are less frequent. This study evaluated the genetic variation within naturally occurring atoxigenic A. flavus strains from the endemic vegetative compatibility group (VCG) YV36. AF36 is a strain of VCG YV36 and was the first fungus used in agriculture for aflatoxin management. Genetic analyses based on mating-type loci, 21 microsatellite loci, and a single nucleotide polymorphism (SNP) in the aflC gene were applied to a set of 237 YV36 isolates collected from 1990 through 2005 from desert legumes and untreated fields and from fields previously treated with AF36 across the southern United States. One haplotype dominated across time and space. No recombination with strains belonging to VCGs other than YV36 was detected. All YV36 isolates carried the SNP in aflC that prevents aflatoxin biosynthesis and the mat1-2 idiomorph at the mating-type locus. These results suggest that VCG YV36 has a clonal population structure maintained across both time and space. These results demonstrate the genetic stability of atoxigenic strains belonging to a broadly distributed endemic VCG in both untreated populations and populations where the short-term frequency of VCG YV36 has increased due to applications of a strain used to competitively exclude aflatoxin producers. This work supports the hypothesis that strains of this VCG are not involved in routine genetic exchange with aflatoxin-producing strains.

  4. Genetic Analysis of the Aspergillus flavus Vegetative Compatibility Group to Which a Biological Control Agent That Limits Aflatoxin Contamination in U.S. Crops Belongs

    PubMed Central

    Cotty, Peter J.

    2015-01-01

    Some filamentous fungi in Aspergillus section Flavi produce carcinogenic secondary compounds called aflatoxins. Aflatoxin contamination is routinely managed in commercial agriculture with strains of Aspergillus flavus that do not produce aflatoxins. These non-aflatoxin-producing strains competitively exclude aflatoxin producers and reshape fungal communities so that strains with the aflatoxin-producing phenotype are less frequent. This study evaluated the genetic variation within naturally occurring atoxigenic A. flavus strains from the endemic vegetative compatibility group (VCG) YV36. AF36 is a strain of VCG YV36 and was the first fungus used in agriculture for aflatoxin management. Genetic analyses based on mating-type loci, 21 microsatellite loci, and a single nucleotide polymorphism (SNP) in the aflC gene were applied to a set of 237 YV36 isolates collected from 1990 through 2005 from desert legumes and untreated fields and from fields previously treated with AF36 across the southern United States. One haplotype dominated across time and space. No recombination with strains belonging to VCGs other than YV36 was detected. All YV36 isolates carried the SNP in aflC that prevents aflatoxin biosynthesis and the mat1-2 idiomorph at the mating-type locus. These results suggest that VCG YV36 has a clonal population structure maintained across both time and space. These results demonstrate the genetic stability of atoxigenic strains belonging to a broadly distributed endemic VCG in both untreated populations and populations where the short-term frequency of VCG YV36 has increased due to applications of a strain used to competitively exclude aflatoxin producers. This work supports the hypothesis that strains of this VCG are not involved in routine genetic exchange with aflatoxin-producing strains. PMID:26092465

  5. Vitality Stains and Real Time PCR Studies to Delineate the Interactions of Pichia anomala and Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to probe the effect of the yeast, P. anomala against A flavus by using real time RT-PCR technique and vitality fluorescent stains. Yeast and fungi were inoculated into a 250 ml-flask containing 50 ml potato dextrose broth (PDB) at yeast to fungus (Y : F) ratios of ...

  6. Facing the problem of "false positives": re-assessment and improvement of a multiplex RT-PCR procedure for the diagnosis of A. flavus mycotoxin producers.

    PubMed

    Degola, F; Berni, E; Spotti, E; Ferrero, I; Restivo, F M

    2009-02-28

    The aim of our research project was to consolidate a multiplex RT-PCR protocol to detect aflatoxigenic strains of Aspergillus flavus. Several independent A. flavus strains were isolated from corn and flour samples from the North of Italy and from three European countries. Aflatoxin producing/not producing phenotype was assessed by qualitative and quantitative assays at day five of growth in aflatoxin inducing conditions. Expression of 16 genes belonging to the aflatoxin cluster was assayed by multiplex or monomeric RT-PCR. There is a good correlation between gene expression and aflatoxin production. Strains that apparently transcribed all the relevant genes but did not release aflatoxin in the medium ("false positives") were re-assessed for mycotoxin production after extended growth in inducing condition. All the "false positive" strains in actual fact were positive when aflatoxin determination was performed after 10 days of growth. These strains should then be re-classified as "slow aflatoxin accumulators". To optimise the diagnostic procedure, a quintuplex RT-PCR procedure was designed consisting of a primer set directed against four informative aflatoxin cluster genes and the beta-tubulin gene as an internal amplification control. In conclusion we have provided evidence for the robustness and reliability of our RT-PCR protocol in discriminating mycotoxin producer from non-producer strains of A. flavus. and the molecular procedure we devised is a promising tool with which to screen and control the endemic population of A. flavus colonising different areas of the World.

  7. Environmental distribution and genetic diversity of vegetative compatibility groups determine biocontrol strategies to mitigate aflatoxin contamination of maize by Aspergillus flavus.

    PubMed

    Atehnkeng, Joseph; Donner, Matthias; Ojiambo, Peter S; Ikotun, Babatunde; Augusto, Joao; Cotty, Peter J; Bandyopadhyay, Ranajit

    2016-01-01

    Maize infected by aflatoxin-producing Aspergillus flavus may become contaminated with aflatoxins, and as a result, threaten human health, food security and farmers' income in developing countries where maize is a staple. Environmental distribution and genetic diversity of A. flavus can influence the effectiveness of atoxigenic isolates in mitigating aflatoxin contamination. However, such information has not been used to facilitate selection and deployment of atoxigenic isolates. A total of 35 isolates of A. flavus isolated from maize samples collected from three agro-ecological zones of Nigeria were used in this study. Ecophysiological characteristics, distribution and genetic diversity of the isolates were determined to identify vegetative compatibility groups (VCGs). The generated data were used to inform selection and deployment of native atoxigenic isolates to mitigate aflatoxin contamination in maize. In co-inoculation with toxigenic isolates, atoxigenic isolates reduced aflatoxin contamination in grain by > 96%. A total of 25 VCGs were inferred from the collected isolates based on complementation tests involving nitrate non-utilizing (nit(-)) mutants. To determine genetic diversity and distribution of VCGs across agro-ecological zones, 832 nit(-) mutants from 52 locations in 11 administrative districts were paired with one self-complementary nitrate auxotroph tester-pair for each VCG. Atoxigenic VCGs accounted for 81.1% of the 153 positive complementations recorded. Genetic diversity of VCGs was highest in the derived savannah agro-ecological zone (H = 2.61) compared with the southern Guinea savannah (H = 1.90) and northern Guinea savannah (H = 0.94) zones. Genetic richness (H = 2.60) and evenness (E5  = 0.96) of VCGs were high across all agro-ecological zones. Ten VCGs (40%) had members restricted to the original location of isolation, whereas 15 VCGs (60%) had members located between the original source of isolation and a distance

  8. Beyond aflatoxin: four distinct expression patterns and functional roles associated with Aspergillus flavus secondary metabolism gene clusters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species of Aspergillus produce a diverse array of secondary metabolites, and recent genomic analysis has predicted that these species have the capacity to synthesize many more compounds. It has been possible to infer the presence of 55 gene clusters associated with secondary metabolism in Aspergill...

  9. The vegetative compatibility group to which the US biocontrol agent Aspergillus flavus AF36 belongs is also endemic to Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are naturally occurring and carcinogenic mycotoxins produced by several members of Aspergillus section Flavi. These potent toxins frequently contaminate maize in warm production areas. Maize provides over half the caloric intake for the majority of the population of Mexico. However, most ...

  10. Characterization of species of the Aspergillus section Nigri from corn field isolates co-infected with Aspergillus flavus/parasiticus species and the potential for ochratoxin A production.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Members of the Aspergillus section Nigri, known as black-spored aspergilli, can contaminate several substrates including maize. Although some species within the group can produce plant disease symptoms such as black mold in onions and maize ear rot, the main concern with A. niger aggregate contamina...

  11. Assessment of mycoflora and infestation of insects, vector of Aspergillus section Flavi, in stored peanut from Argentina.

    PubMed

    Nesci, Andrea; Montemarani, Analía; Etcheverry, Miriam

    2011-02-01

    The occurrence of spoilage fungi and Aspergillus section Flavi populations, the aflatoxins incidence, the role of insects as vectors of mycotoxin-producing fungi and the AFs-producing ability of the isolated species throughout the peanut (Arachis hypogaea L.) storage period were evaluated. Analyses of fungal populations from 95 peanut seed samples did not demonstrate significant differences between the incidences in each sampling period. Aspergillus section Flavi were isolated during all incubation periods. Cryptolestes spp. (Coleoptera: Cucujidae) were collected in August, September and October with 18, 16 and 28% of peanut samples contaminated, respectively. Insects isolated during August showed 69% of Aspergillus section Flavi contamination. A. flavus was the most frequently isolated (79%) from peanut seeds and from insect (59%). The greater levels of AFB1 were detected in September and October with a mean of 68.86 μg/kg and 69.12 μg/kg respectively. The highest proportion of A. flavus toxigenic strains (87.5%) was obtained in June. The presence of Aspergillus section Flavi and insect vectors of aflatoxigenic fungi presented a potential risk for aflatoxin production during the peanut storage period. Integrated management of fungi and insect vectors is in progress.

  12. Large crystal growth by thermal control allows combined X-ray and neutron crystallographic studies to elucidate the protonation states in Aspergillus flavus urate oxidase

    PubMed Central

    Oksanen, E.; Blakeley, M. P.; Bonneté, F.; Dauvergne, M. T.; Dauvergne, F.; Budayova-Spano, M.

    2009-01-01

    Urate oxidase (Uox) catalyses the oxidation of urate to allantoin and is used to reduce toxic urate accumulation during chemotherapy. X-ray structures of Uox with various inhibitors have been determined and yet the detailed catalytic mechanism remains unclear. Neutron crystallography can provide complementary information to that from X-ray studies and allows direct determination of the protonation states of the active-site residues and substrate analogues, provided that large, well-ordered deuterated crystals can be grown. Here, we describe a method and apparatus used to grow large crystals of Uox (Aspergillus flavus) with its substrate analogues 8-azaxanthine and 9-methyl urate, and with the natural substrate urate, in the presence and absence of cyanide. High-resolution X-ray (1.05–1.20 Å) and neutron diffraction data (1.9–2.5 Å) have been collected for the Uox complexes at the European Synchrotron Radiation Facility and the Institut Laue-Langevin, respectively. In addition, room temperature X-ray data were also collected in preparation for joint X-ray and neutron refinement. Preliminary results indicate no major structural differences between crystals grown in H2O and D2O even though the crystallization process is affected. Moreover, initial nuclear scattering density maps reveal the proton positions clearly, eventually providing important information towards unravelling the mechanism of catalysis. PMID:19586953

  13. Defense Responses to Mycotoxin-Producing Fungi Fusarium proliferatum, F. subglutinans, and Aspergillus flavus in Kernels of Susceptible and Resistant Maize Genotypes.

    PubMed

    Lanubile, Alessandra; Maschietto, Valentina; De Leonardis, Silvana; Battilani, Paola; Paciolla, Costantino; Marocco, Adriano

    2015-05-01

    Developing kernels of resistant and susceptible maize genotypes were inoculated with Fusarium proliferatum, F. subglutinans, and Aspergillus flavus. Selected defense systems were investigated using real-time reverse transcription-polymerase chain reaction to monitor the expression of pathogenesis-related (PR) genes (PR1, PR5, PRm3, PRm6) and genes protective from oxidative stress (peroxidase, catalase, superoxide dismutase and ascorbate peroxidase) at 72 h postinoculation. The study was also extended to the analysis of the ascorbate-glutathione cycle and catalase, superoxide dismutase, and cytosolic and wall peroxidases enzymes. Furthermore, the hydrogen peroxide and malondialdehyde contents were studied to evaluate the oxidation level. Higher gene expression and enzymatic activities were observed in uninoculated kernels of resistant line, conferring a major readiness to the pathogen attack. Moreover expression values of PR genes remained higher in the resistant line after inoculation, demonstrating a potentiated response to the pathogen invasions. In contrast, reactive oxygen species-scavenging genes were strongly induced in the susceptible line only after pathogen inoculation, although their enzymatic activity was higher in the resistant line. Our data provide an important basis for further investigation of defense gene functions in developing kernels in order to improve resistance to fungal pathogens. Maize genotypes with overexpressed resistance traits could be profitably utilized in breeding programs focused on resistance to pathogens and grain safety.

  14. Aflatoxins B and g contamination and aflatoxigenic fungi in nutmeg.

    PubMed

    Okano, Kiyoshi; Tomita, Tsuneyoshi; Ohzu, Yuji; Takai, Mitsuhiro; Ose, Ayaka; Kotsuka, Akiko; Ikeda, Naoko; Sakata, Junko; Kumeda, Yuko; Nakamura, Nobuya; Ichinoe, Masakatsu

    2012-01-01

    This study examined the distribution of aflatoxigenic fungi in 25 imported Indonesian nutmeg samples contaminated with aflatoxins Bs or Bs and Gs. The incidence of aflatoxigenic fungi in the samples contaminated with high levels of aflatoxin was significantly higher than that in the samples with low levels of the toxins(r=0.752). The aflatoxin production of isolates from the samples in cultures of YES broth was examined by means of TLC and HPLC analyses. The ability of isolates to produce aflatoxins did not necessarily correlate with the contamination levels of aflatoxin in the samples. We isolated aflatoxins B and G-producing fungi from 3 samples contaminated with the high levels of aflatoxins B and G. The aflatoxigenic isolates were identified as Aspergillus nomius and A. bombycis based on morphological characters, growth rates at 37°C and 42°C and also molecular-genetic methods. Our results indicate that these two species are mainly responsible for aflatoxin G contamination in nutmeg products.

  15. A Survey of Aflatoxin-Producing Aspergillus sp. from Peanut Field Soils in Four Agroecological Zones of China

    PubMed Central

    Zhang, Chushu; Selvaraj, Jonathan Nimal; Yang, Qingli; Liu, Yang

    2017-01-01

    Peanut pods are easily infected by aflatoxin-producing Aspergillus sp.ecies from field soil. To assess the aflatoxin-producing Aspergillus sp. in different peanut field soils, 344 aflatoxin-producing Aspergillus strains were isolated from 600 soil samples of four agroecological zones in China (the Southeast coastal zone (SEC), the Yangtze River zone (YZR), the Yellow River zone (YR) and the Northeast zone (NE)). Nearly 94.2% (324/344) of strains were A. flavus and 5.8% (20/344) of strains were A. parasiticus. YZR had the highest population density of Aspergillus sp. and positive rate of aflatoxin production in isolated strains (1039.3 cfu·g−1, 80.7%), the second was SEC (191.5 cfu·g−1, 48.7%), the third was YR (26.5 cfu·g−1, 22.7%), and the last was NE (2.4 cfu·g−1, 6.6%). The highest risk of AFB1 contamination on peanut was in YZR which had the largest number of AFB1 producing isolates in 1g soil, followed by SEC and YR, and the lowest was NE. The potential risk of AFB1 contamination in peanuts can increase with increasing population density and a positive rate of aflatoxin-producing Aspergillus sp. in field soils, suggesting that reducing aflatoxigenic Aspergillus sp. in field soils could prevent AFB1 contamination in peanuts. PMID:28117685

  16. Improvement of the antifungal activity of Litsea cubeba vapor by using a helium-neon (He-Ne) laser against Aspergillus flavus on brown rice snack bars.

    PubMed

    Suhem, Kitiya; Matan, Narumol; Matan, Nirundorn; Danworaphong, Sorasak; Aewsiri, Tanong

    2015-12-23

    The aim of this study was to improve the antifungal activity of the volatile Litsea cubeba essential oil and its main components (citral and limonene) on brown rice snack bars by applying He-Ne laser treatment. Different volumes (50-200 μL) of L. cubeba, citral or limonene were absorbed into a filter paper and placed inside an oven (18 L). Ten brown rice snack bars (2 cm wide × 4 cm long × 0.5 cm deep) were put in an oven and heated at 180 °C for 20 min. The shelf-life of the treated snack bars at 30 °C was assessed and sensory testing was carried out to investigate their consumer acceptability. A count of total phenolic content (TPC) and Fourier transform infrared spectroscopy (FTIR) on the properties of essential oil, citral, and limonene before and after the laser treatment was studied for possible modes of action. It was found that the laser treatment improved the antifungal activity of the examined volatile L. cubeba and citral with Aspergillus flavus inhibition by 80% in comparison with those of the control not treated with the laser. L. cubeba vapor at 100 μL with the laser treatment was found to completely inhibit the growth of natural molds on the snack bars for at least 25 days; however, without essential oil vapor and laser treatment, naturally contaminating mold was observed in 3 days. Results from the sensory tests showed that the panelists were unable to detect flavor and aroma differences between essential oil treatment and the control. Laser treatment caused an increase in TPC of citral oil whereas the TPC in limonene showed a decrease after the laser treatment. These situations could result from the changing peak of the aliphatic hydrocarbons that was revealed by the FTIR spectra.

  17. Abiotic factors and their interactions influence on the co-production of aflatoxin B(1) and cyclopiazonic acid by Aspergillus flavus isolated from corn.

    PubMed

    Astoreca, Andrea; Vaamonde, Graciela; Dalcero, Ana; Marin, Sonia; Ramos, Antonio

    2014-04-01

    The objectives of this study were i) to determine the effects of the interactions of water activity, temperature and incubation time on the co-production of AFB1 and CPA by isolates of Aspergillus flavus with different profile of mycotoxin production and ii) to identify the aW and temperature limiting conditions for the production of both mycotoxins. Fungi used in this study were selected because they belonged to different chemotypes: chemotype I (AFB1+/CPA+), III (AFB1+/CPA-) and IV (AFB1-/CPA+), respectively. Two culture media were used; Czapek yeast agar (CYA) and corn extract agar (CEM), at different incubated temperatures (10-40 °C) and aW levels (0.80-0.98). AFB1 and CPA production were analyzed after 7, 14, 21 and 28 days of incubation. Significant differences were observed with respect to mycotoxin production depending on the media evaluated. The AFB1 production occurred more favorably on CYA while the highest CPA concentrations were recorded on CEM. Within the range of aW evaluated in this study, 0.83 was the limiting level for both toxins production. The optimum conditions for AFB1 production occurred at 0.96 aW and 30 °C after 21 days of incubation, regardless of the media and isolate. Although different amounts of toxins were produced in each medium, the limiting and optimum conditions for their production were similar in both. No differences in the response of the three isolates to the abiotic factors discussed were observed despite belonging to different chemotypes. The determination of the thresholds of mycotoxins co-production, especially in the case of data obtained with the corn extract medium can be useful to avoid the conditions conducive to co-occurrence of these mycotoxins in corn.

  18. Microarray-Based Mapping for the Detection of Molecular Markers in Response to Aspergillus flavus Infection in Susceptible and Resistant Maize Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were (1) to evaluate differential gene expression levels for resistance to A. flavus kernel infection in susceptible (Va35) and resistant (Mp313E) maize lines using Oligonucleotide and cDNA microarray analysis, (2) to evaluate differences in A. flavus accumulation betwee...

  19. Description of Aspergillus flavus growth under the influence of different factors (water activity, incubation temperature, protein and fat concentration, pH, and cinnamon essential oil concentration) by kinetic, probability of growth, and time-to-detection models.

    PubMed

    Kosegarten, Carlos E; Ramírez-Corona, Nelly; Mani-López, Emma; Palou, Enrique; López-Malo, Aurelio

    2017-01-02

    A Box-Behnken design was used to determine the effect of protein concentration (0, 5, or 10g of casein/100g), fat (0, 3, or 6g of corn oil/100g), aw (0.900, 0.945, or 0.990), pH (3.5, 5.0, or 6.5), concentration of cinnamon essential oil (CEO, 0, 200, or 400μL/kg) and incubation temperature (15, 25, or 35°C) on the growth of Aspergillus flavus during 50days of incubation. Mold response under the evaluated conditions was modeled by the modified Gompertz equation, logistic regression, and time-to-detection model. The obtained polynomial regression models allow the significant coefficients (p<0.05) for linear, quadratic and interaction effects for the Gompertz equation's parameters to be identified, which adequately described (R(2)>0.967) the studied mold responses. After 50days of incubation, every tested model system was classified according to the observed response as 1 (growth) or 0 (no growth), then a binary logistic regression was utilized to model A. flavus growth interface, allowing to predict the probability of mold growth under selected combinations of tested factors. The time-to-detection model was utilized to estimate the time at which A. flavus visible growth begins. Water activity, temperature, and CEO concentration were the most important factors affecting fungal growth. It was observed that there is a range of possible combinations that may induce growth, such that incubation conditions and the amount of essential oil necessary for fungal growth inhibition strongly depend on protein and fat concentrations as well as on the pH of studied model systems. The probabilistic model and the time-to-detection models constitute another option to determine appropriate storage/processing conditions and accurately predict the probability and/or the time at which A. flavus growth occurs.

  20. Effect of antioxidants of aflatoxigenic molds

    SciTech Connect

    Ahmad, M.M.

    1986-01-01

    Growth and aflatoxin production by Aspergillus flavus and A. parasiticus were measured in synthetic media and chicken feed treated with butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ethoxyquin (EXQ), propyl gallate (PG) or t-butylhydroquinone (TBHQ) at 50-250 ..mu..g/g and 50-1000 ..mu..g/g, respectively. BHA at 50 ..mu..g/g in broth or agar inhibited growth and alfatoxin production by both molds. In poultry feeds, 1000 ..mu..g/g BHA was required to depress CO/sub 2/ production at day 5 of incubation, while 200 ..mu..g/g decreased aflatoxin B/sub 1/ 23.8%. BHT, EXQ, and PG had slight effects on mold growth while TBHQ enhanced growth on broth but reduced it on agar. Afaltoxin B/sub 1/ production was stimulated by EXQ, although G/sub 1/ production declines. Measurement of cellular constituents released from mycelia over 5 hours indicated that BHA doubled the release of UV-absorbing materials and increase by threefold the release of previously incorporated radiolabeled compounds. Furthermore, BHA inhibited the uptake of /sup 14/C-amino acids 8 and 44%, /sup 3/H-uridine 65 and 91%, and /sup 3/H-methyl thymidine 67 and 71%, for A. flavus and A. parasiticus, respectively, compared to untreated controls.

  1. Atypical Aspergillus parasiticus isolates from pistachio with aflR gene nucleotide insertion identical to Aspergillus sojae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are the most toxic and carcinogenic secondary metabolites produced primarily by the filamentous fungi Aspergillus flavus and Aspergillus parasiticus. The toxins cause devastating economic losses because of strict regulations on distribution of contaminated products. Aspergillus sojae are...

  2. 76 FR 16297 - Aspergillus flavus

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... or infectivity in animals exposed to high levels of this active ingredient. 2. Drinking water... observed by analysis of the active ingredient. Field trial data presented by the petitioner to EPA.... Gagliardi, PhD and J.L. Kough, PhD to S. Bacchus dated February 24, 2011 (available as...

  3. Regulation of aflatoxin biosynthesis and branched-chain amino acids metabolism in Aspergillus flavus by 2-phenylethanol reveal biocontrol mechanism of Pichia anomala

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pichia anomala WRL-076 is a biocontrol yeast which has been shown to inhibit growth and aflatoxin production of A. flavus. Using the SPME-GC/MS analysis we identified that the volatile, 2-phenylethanol (2-PE) produced by this yeast and demonstrated that the compound inhibited aflatoxin production. W...

  4. A network approach of gene co-expression in the zea mays/Aspergillus flavus pathosystem to map host/pathogen interaction pathways

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A gene co-expression network was generated using a dual RNA-seq study with the fungal pathogen A. flavus and its plant host Z. mays during the initial 3 days of infection. The analysis deciphered novel pathways and mapped genes of interest in both organisms during the infection. This network reveal...

  5. Microbiological and physicochemical factors affecting Aspergillus section Flavi incidence in Cavendish banana (Musa cavendishii) chips production in Southern Philippines.

    PubMed

    Sales, A C; Azanza, P V; Yoshizawa, T

    2005-01-01

    Microbiological and physicochemical factors affecting the incidence of Aspergillus section Flavi in dried Cavendish banana (Musa cavendishii) chips production in Southern Philippines were examined. The average counts of Aspergillus section Flavi (AFC) in fresh and dried Cavendish bananas from 10 production batches of the Philippine Agro-Industrial Development Cooperative in Davao del Norte, Southern Philippines were 1.2 x 10(2) and 1.6 x 10(2) cfu/g, respectively. Isolates from both samples were identified to be Aspergillus flavus based on spore type and conidial structure of isolates. An increasing trend in the AFC of Cavendish bananas was observed during dried banana chips processing. Variability in the AFC between production batches was attributed to differences in aerobic and fungal populations and physicochemical characteristics of the fruits, peel damage of the raw materials, concentration of AFC in the air and food-contact surfaces of the production area, and temperature and relative humidity (RH) conditions of the environment during production and storage. Physicochemical characteristics of Cavendish bananas from the receipt of raw materials up to the first day of drying were within the reported range of values allowing growth and toxin production by aflatoxigenic fungi. Air-borne AFC varied depending on the section of the production area examined. The close proximity of the waste disposal area from the production operation to the preparation, drying and storage areas suggests that cross-contamination, probably air-borne or insect-borne was a likely occurrence. The hands of workers were also identified as AFC sources. Results of this study highlight the need for the development of strategies to control aflatoxigenic fungi and aflatoxin contamination in Philippine dried Cavendish bananas.

  6. Mycobiota of ground red pepper and their aflatoxigenic potential.

    PubMed

    Ham, Hyeonheui; Kim, Sosoo; Kim, Min-Hee; Lee, Soohyung; Hong, Sung Kee; Ryu, Jae-Gee; Lee, Theresa

    2016-12-01

    To investigate contamination of ground red pepper with fungi and mycotoxin, we obtained 30 ground red pepper samples from 15 manufacturers in the main chili-pepper-producing areas in Korea. Fungal contamination was evaluated by spreading diluted samples on potato dextrose agar plates. The total fungi counts ranged from 0 to 7.3 × 10(3) CFU/g. In the samples, the genus Aspergillus had the highest incidence, while Paecilomyces was isolated most frequently. The next most frequent genera were Rhizopus, Penicillium, Cladosporium, and Alternaria. Within Aspergillus, A. ruber was predominant, followed by A. niger, A. amstelodami, A. ochraceus, A. terreus, A. versicolor, A. flavus, and A. fumigatus. The samples were analyzed for aflatoxins, ochratoxin A, and citrinin by ultra-perfomance liquid chromatography (UPLC) with a fluorescence detector. Ochratoxin A was detected from three samples at 1.03‒2.08 μg/kg, whereas no aflatoxins or citrinin were detected. To test the potential of fungal isolates to produce aflatoxin, we performed a PCR assay that screened for the norB-cypA gene for 64 Aspergillus isolates. As a result, a single 800-bp band was amplified from 10 A. flavus isolates, and one Aspergillus sp. isolate. UPLC analyses confirmed aflatoxin production by nine A. flavus isolates and one Aspergillus sp. isolate, which produced total aflatoxins at 146.88‒909.53 μg/kg. This indicates that continuous monitoring of ground red pepper for toxigenic fungi is necessary to minimize mycotoxin contamination.

  7. Direct and rapid discrimination of aflatoxigenic strains based on fibre-optic room temperature phosphorescence detection.

    PubMed

    Rojas-Durán, T; Sánchez-Barragán, I; Costa-Fernández, J M; Sanz-Medel, A

    2007-04-01

    An innovative analytical methodology for the rapid identification of aflatoxin-producing moulds belonging to Aspergillus genus is presented here. The procedure is based on the measurement, using a fibre-optic luminometer, of the room temperature phosphorescence (RTP) emitted by aflatoxins produced by isolated aflatoxigenic strains, cultured in a special culture medium consisting of malt extract agar modified with beta-cyclodextrin and sodium deoxycholate for RTP induction. Unequivocal detection of the presence of aflatoxins in the culture medium is achieved within the first 36 h of incubation at 32 degrees C, owing to the selectivity and sensitivity of the RTP emission, as compared with the minimum of 72 h needed using a conventional microbiological method. In a first step, the capability of aflatoxin standard solutions to emit analytically useful RTP was evaluated. In this line all experimental conditions were optimised for in vitro induction of RTP from aflatoxins. In a second step, a simple analytical test was developed and it has been evaluated for the rapid identification of aflatoxigenic strains, as a discriminating assay from non-aflatoxigenic strains based on the measurement of experimental RTP emission observed. Confirmation of aflatoxin production on the studied culture plates was accomplished by means of an HPLC/fluorescence reference method.

  8. The biodiversity of Aspergillus section Flavi in brazil nuts: from rainforest to consumer.

    PubMed

    Calderari, Thaiane O; Iamanaka, Beatriz T; Frisvad, Jens C; Pitt, John I; Sartori, Daniele; Pereira, Jose Luiz; Fungaro, Maria Helena P; Taniwaki, Marta H

    2013-01-01

    A total of 288 brazil nut samples (173 kernel and 115 shell) from the Amazon rainforest region and São Paulo State, Brazil were collected at different stages of brazil nut production. Samples were analysed for: percentages of aflatoxigenic fungal species and potential for aflatoxin production and presence of aflatoxins. Aspergillus nomius was the most common species found (1235 isolates) which amounted to 30% of the total species with potential to produce aflatoxins. This species is of concern since 100% of all isolates produced aflatoxins B(1), B(2), G(1) and G(2). Aspergillus flavus was almost equally common (1212 isolates) although only 46% produced aflatoxins under laboratory conditions, and only aflatoxins B(1) and B(2). Low number of other species with the potential to produce aflatoxins was isolated: Aspergillus arachidicola and Aspergillus bombycis produced B and G aflatoxins whilst Aspergillus pseudotamarii produced only aflatoxin B(1). The total aflatoxin levels found in samples taken from the rainforests was 0.7 μg/kg, from processing plants before and after sorting 8.0 and 0.1 μg/kg respectively, from street markets in the Amazon region 6.3 μg/kg and from supermarkets in São Paulo State 0.2 μg/kg. Processing, which included manual or mechanical sorting and drying at 60°C for 30 to 36 h, eliminated on average more than 98% of total aflatoxins. These results showed that sorting is a very effective way to decrease aflatoxin content in brazil nuts.

  9. Efficacy of Some Essential Oils Against Aspergillus flavus with Special Reference to Lippia alba Oil an Inhibitor of Fungal Proliferation and Aflatoxin B1 Production in Green Gram Seeds during Storage.

    PubMed

    Pandey, Abhay K; Sonker, Nivedita; Singh, Pooja

    2016-04-01

    During mycofloral analysis of green gram (Vigna radiata (L.) R. Wilczek) seed samples taken from different grocery stores by agar and standard blotter paper methods, 5 fungal species were identified, of which Aspergillus flavus exhibited higher relative frequency (75.20% to 80.60%) and was found to produce aflatoxin B1 . On screening of 11 plant essential oils against this mycotoxigenic fungi, Lippia alba essential oil was found to be most effective and showed absolute inhibition of mycelia growth at 0.28 μL/mL. The oil of L. alba was fungistatic and fungicidal at 0.14 and 0.28 μL/mL, respectively. Oil had broad range of fungitoxicity at its MIC value and was absolutely inhibited the AFB1 production level at 2.0 μL/mL. Chemical analysis of this oil revealed geranial (36.9%) and neral (29.3%) as major components followed by myrcene (18.6%). Application of a dose of 80 μL/0.25 L air of Lippia oil in the storage system significantly inhibited the fungal proliferation and aflatoxin production without affecting the seed germination rate. By the virtue of fungicidal, antiaflatoxigenic nature and potent efficacy in storage food system, L. alba oil can be commercialized as botanical fungicide for the protection of green gram seeds during storage.

  10. A Novel Non-Cumbersome Approach Towards Biosynthesis of Pectic-Oligosaccharides by Non-Aflatoxigenic Aspergillus sp. Section Flavi Strain EGY1 DSM 101520 through Citrus Pectin Fermentation

    PubMed Central

    Embaby, Amira M.; Melika, Ramy R.; Hussein, Ahmed; El-Kamel, Amal H.; Marey, Heba S.

    2016-01-01

    Pectic-Oligosaccharides (POS) have a growing potential in food and feed industries. To satisfy the demand of worldwide markets from POS and avoid the shortcomings of currently applied methodologies encountered in their preparation, the present study highlights a novel robust approach for POS biosynthesis. In the current approach, Aspergillus sp.section Flavi strain EGY1 DSM 101520 was grown on citrus pectin-based medium as a core POS production medium. POS' levels accumulated in the fungal fermentation broth were optimized through a three step sequential statistical mathematical methodology; Plackett-Burman design (PBD), Box-Behnken design (BBD) and canonical analysis. Three key determinants namely citrus pectin, peptone and NaH2PO4 were pointed out by PBD to impose significant consequences (P<0.05) on the process outcome (POS' levels). Optimal levels of these key determinants along with maximal of POS' levels were set by BBD and canonical analysis to be 2.28% (w/v) citrus pectin, 0.026% (w/v) peptone and 0.28% (w/v) NaH2PO4 to achieve a net amount of 1.3 g POS /2.28 g citrus pectin. Through this approach, a yield of 57% (w/w) POS of the total citrus pectin was obtained after 24 h of fungal growth on optimized citrus pectin–based medium. A fold enhancement of 13 times in POS' levels released in the fermentation fungal broth was realized by the end of the optimization strategy. This novel robust approach is considered a new insight towards POS biosynthesis via efficient, rapid and non-cumbersome procedure. To the best of authors' knowledge, the present work is the first article underlining detailed POS production from the fermentation broth of a fungus growing on citrus pectin-based medium. PMID:27992459

  11. Formation of 1-octen-3-ol from Aspergillus flavus conidia is accelerated after disruption of cells independently of Ppo oxygenases, and is not a main cause of inhibition of germination.

    PubMed

    Miyamoto, Kana; Murakami, Tomoko; Kakumyan, Pattana; Keller, Nancy P; Matsui, Kenji

    2014-01-01

    Eight-carbon (C8) volatiles, such as 1-octen-3-ol, are ubiquitous among fungi. They are the volatiles critical for aroma and flavor of fungi, and assumed to be signals controlling germination of several fungi. In this study, we found that intact Aspergillus flavus conidia scarcely synthesized C8 volatiles but repeated freeze-thaw treatment that made the cell membrane permeable promoted (R)-1-octen-3-ol formation. Loss or down regulation of any one of five fatty acid oxygenases (PpoA, PpoB, PpoC, PpoD or lipoxygenase) hypothesized contribute to 1-octen-3-ol formation had little impact on production of this volatile. This suggested that none of the oxygenases were directly involved in the formation of 1-octen-3-ol or that compensatory pathways exist in the fungus. Germination of the conidia was markedly inhibited at high density (1.0 × 10(9)spores mL(-1)). It has been postulated that 1-octen-3-ol is an autoinhibitor suppressing conidia germination at high density. 1-Octen-3-ol at concentration of no less than 10 mM was needed to suppress the germination while the concentration of 1-octen-3-ol in the suspension at 1.0 × 10(9) mL(-1) was under the detection limit (<1 µM). Thus, 1-octen-3-ol was not the principal component responsible for inhibition of germination. Instead, it was evident that the other heat-labile factor(s) suppressed conidial germination.

  12. Candida parapsilosis as a Potent Biocontrol Agent against Growth and Aflatoxin Production by Aspergillus Species

    PubMed Central

    Niknejad, F; Zaini, F; Faramarzi, MA; Amini, M; Kordbacheh, P; Mahmoudi, M; Safara, M

    2012-01-01

    Background: Aflatoxin contamination of food and feed stuff is a serious health problem and significant economic concerns. In the present study, the inhibitory effect of Candida parapsilosis IP1698 on mycelial growth and aflatoxin production in aflatoxigenic strains of Aspergillus species was investigated. Methods: Mycelial growth inhibitions of nine strains of aflatoxigenic and non-aflatoxigenic Aspergillus species in the presence of C. parapsilosis investigated by pour plate technique at different pH, temperature and time of incubation. Reduction of aflatoxin was evaluated in co-cultured fungi in yeast extract sucrose broth after seven days of incubation using HPLC method. The data were analyzed by SPSS 11.5. Results: The presence of the C. parapsilosis at different pH did not affect significantly the growth rate of Aspergillus isolates. On the other hand, temperature and time of incubation showed to be significantly effective when compared to controls without C. parapsilosis (P≤0.05). In aflatoxigenic strains, minimum percentage of reductions in total aflatoxin and B1, B2, G1, G2 fractions were 92.98, 92.54, 77.48, 54.54 and 72.22 and maximum percentage of reductions were 99.59, not detectable, 94.42, and not detectable in both G1 and G2, respectively. Conclusion: C. parapsilosis might employ as a good biocontrol agent against growth and aflatoxin production by aflatoxigenic Aspergillus species PMID:23308351

  13. Efficacy of corn silage inoculants on the fermentation quality under farm conditions and their influence on Aspergillus parasitucus, A. flavus and A. fumigatus determined by q-PCR.

    PubMed

    Dogi, Cecilia A; Pellegrino, Matías; Poloni, Valeria; Poloni, Luis; Pereyra, Carina M; Sanabria, Analía; Pianzzola, María Julia; Dalcero, Ana; Cavaglieri, Lilia

    2015-01-01

    Laboratory-scale silos were prepared to evaluate the efficacy of two different lactic acid bacteria (LAB) on the fermentation quality and mycobiota of corn silage. Their influence on Aspergillus species' variability by using the q-PCR technique was studied. Silage inoculated with Lactobacillus rhamnosus RC007 or L. plantarum RC009 were compared with uninoculated silage. Silos were opened after 1, 7, 45, 90 and 120 days after ensiling. At the end of the ensiling period, silos were left open for 7 days to evaluate aerobic stability. Rapid lactic acid production and decline in pH values were seen in the early stages of fermentation in silage inoculated with L. rhamnosus RC007. After aerobic exposure, a significant decline in lactic acid content was observed in untreated and L. plantarum RC009-inoculated silages. Counts for yeasted and toxigenic fungus remained lower, after aerobic exposure, in L. rhamnosus RC007-inoculated silage, in comparison with L. plantarum RC009 and uninoculated silages. Comparing the influence exerted by both BAL, it was observed that L. rhamnosus RC007 was more efficient at inhibiting the three fungal species tested whose DNA concentrations, determined by q-PCR, oscillated near the initial value (pre-ensiling maize). The ability of L. rhamnosus RC007 to produce lactic acid rapidly and the decline in pH values in the early stages of the fermentation along with the reduction of yeast and mycotoxicogenic fungus after aerobic exposure shows its potential as a bio-control inoculant agent in animal feed.

  14. Biodiversity of Aspergillus section Flavi in the United States: a review.

    PubMed

    Horn, Bruce W

    2007-10-01

    Fungi belonging to Aspergillus section Flavi are of great economic importance in the United States due to their ability to produce toxic and carcinogenic aflatoxins in agricultural commodities. Development of control strategies against A. flavus and A. parasiticus, the major aflatoxin-producing species, is dependent upon a basic understanding of their diversity in agricultural ecosystems. This review summarizes our current knowledge of species and population diversity in the United States in relation to morphology, mycotoxin production and genetic characters. The high genetic diversity in populations of aflatoxigenic fungi is a reflection of their versatile habits in nature, which include saprotrophic colonization of plant debris in soil and parasitism of seeds and grain. Genetic variation within populations may originate from a cryptic sexual state. The advent of intensive monoculture agriculture not only increases population size but also may introduce positive selective pressure for aflatoxin production due to its link with pathogenicity in crops. Important goals in population research are to determine how section Flavi diversity in agricultural ecosystems is changing and to measure the direction of this evolution.

  15. Thermophilic Fungi to Dominate Aflatoxigenic/Mycotoxigenic Fungi on Food under Global Warming

    PubMed Central

    Paterson, Robert Russell M.; Lima, Nelson

    2017-01-01

    Certain filamentous fungi produce mycotoxins that contaminate food. Mycotoxin contamination of crops is highly influenced by environmental conditions and is already affected by global warming, where there is a succession of mycotoxigenic fungi towards those that have higher optimal growth temperatures. Aflatoxigenic fungi are at the highest limit of temperature although predicted increases in temperature are beyond that constraint. The present paper discusses what will succeed these fungi and represents the first such consideration. Aflatoxins are the most important mycotoxins and are common in tropical produce, much of which is exported to temperate regions. Hot countries may produce safer food under climate change because aflatoxigenic fungi will be inhibited. The same situation will occur in previously temperate regions where these fungi have recently appeared, although decades later. Existing thermotolerant and thermophilic fungi (TTF) will dominate, in contrast to the conventional mycotoxigenic fungi adapting or mutating, as it will be quicker. TTF produce a range of secondary metabolites, or potential mycotoxins and patulin which may become a new threat. In addition, Aspergillus fumigatus will appear more frequently, a serious human pathogen, because it is (a) thermotolerant and (b) present on crops: hence this is an even greater problem. An incubation temperature of 41 °C needs employing forthwith to detect TTF. Finally, TTF in crops requires study because of the potential for diseases in humans and animals under climate change. PMID:28218685

  16. Thermophilic Fungi to Dominate Aflatoxigenic/Mycotoxigenic Fungi on Food under Global Warming.

    PubMed

    Paterson, Robert Russell M; Lima, Nelson

    2017-02-17

    Certain filamentous fungi produce mycotoxins that contaminate food. Mycotoxin contamination of crops is highly influenced by environmental conditions and is already affected by global warming, where there is a succession of mycotoxigenic fungi towards those that have higher optimal growth temperatures. Aflatoxigenic fungi are at the highest limit of temperature although predicted increases in temperature are beyond that constraint. The present paper discusses what will succeed these fungi and represents the first such consideration. Aflatoxins are the most important mycotoxins and are common in tropical produce, much of which is exported to temperate regions. Hot countries may produce safer food under climate change because aflatoxigenic fungi will be inhibited. The same situation will occur in previously temperate regions where these fungi have recently appeared, although decades later. Existing thermotolerant and thermophilic fungi (TTF) will dominate, in contrast to the conventional mycotoxigenic fungi adapting or mutating, as it will be quicker. TTF produce a range of secondary metabolites, or potential mycotoxins and patulin which may become a new threat. In addition, Aspergillus fumigatus will appear more frequently, a serious human pathogen, because it is (a) thermotolerant and (b) present on crops: hence this is an even greater problem. An incubation temperature of 41 °C needs employing forthwith to detect TTF. Finally, TTF in crops requires study because of the potential for diseases in humans and animals under climate change.

  17. Time-course of germination, initiation of mycelium proliferation and probability of visible growth and detectable AFB1 production of an isolate of Aspergillus flavus on pistachio extract agar.

    PubMed

    Aldars-García, Laila; Sanchis, Vicente; Ramos, Antonio J; Marín, Sonia

    2017-06-01

    The aim of this work was to assess the temporal relationship among quantified germination, mycelial growth and aflatoxin B1 (AFB1) production from colonies coming from single spores, in order to find the best way to predict as accurately as possible the presence of AFB1 at the early stages of contamination. Germination, mycelial growth, probability of growth and probability of AFB1 production of an isolate of Aspergillus flavus were determined at 25 °C and two water activities (0.85 and 0.87) on 3% Pistachio Extract Agar (PEA). The percentage of germinated spores versus time was fitted to the modified Gompertz equation for the estimation of the germination parameters (geometrical germination time and germination rate). The radial growth curve for each colony was fitted to a linear model for the estimation of the apparent lag time for growth and the growth rate, and besides the time to visible growth was estimated. Binary data obtained from growth and AFB1 studies were modeled using logistic regression analysis. Both water activities led to a similar fungal growth and AFB1 production. In this study, given the suboptimal set conditions, it has been observed that germination is a stage far from the AFB1 production process. Once the probability of growth started to increase it took 6 days to produce AFB1, and when probability of growth was 100%, only a 40-57% probability of detection of AFB1 production was predicted. Moreover, colony sizes with a radius of 1-2 mm could be a helpful indicator of the possible AFB1 contamination in the commodity. Despite growth models may overestimate the presence of AFB1, their use would be a helpful tool for producers and manufacturers; from our data 5% probability of AFB1 production (initiation of production) would occur when a minimum of 60% probability of growth is observed. Legal restrictions are quite severe for these toxins, thus their control from the early stages of contamination throughout the food chain is of paramount

  18. RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem.

    PubMed

    Arias, Renée S; Dang, Phat M; Sobolev, Victor S

    2015-12-21

    The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That represents 100 million tons of food being destroyed or diverted to non-human consumption each year. Aflatoxins are powerful carcinogens normally accumulated by the fungi Aspergillus flavus and A. parasiticus in cereals, nuts, root crops and other agricultural products. Silencing of five aflatoxin-synthesis genes by RNA interference (RNAi) in peanut plants was used to control aflatoxin accumulation following inoculation with A. flavus. Previously, no method existed to analyze the effectiveness of RNAi in individual peanut transgenic events, as these usually produce few seeds, and traditional methods of large field experiments under aflatoxin-conducive conditions were not an option. In the field, the probability of finding naturally contaminated seeds is often 1/100 to 1/1,000. In addition, aflatoxin contamination is not uniformly distributed. Our method uses few seeds per transgenic event, with small pieces processed for real-time PCR (RT-PCR) or small RNA sequencing, and for analysis of aflatoxin accumulation by ultra-performance liquid chromatography (UPLC). RNAi-expressing peanut lines 288-72 and 288-74, showed up to 100% reduction (p ≤ 0.01) in aflatoxin B1 and B2 compared to the control that accumulated up to 14,000 ng · g(-1) of aflatoxin B1 when inoculated with aflatoxigenic A. flavus. As reference, the maximum total of aflatoxins allowable for human consumption in the United States is 20 ng · g(-1). This protocol describes the application of RNAi-mediated control of aflatoxins in transgenic peanut seeds and methods for its evaluation. We believe that its application in breeding of peanut and other crops will bring rapid advancement in this important area of science, medicine and human nutrition, and will significantly contribute to the international effort to control aflatoxins, and potentially other

  19. RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem

    PubMed Central

    Arias, Renée S.; Dang, Phat M.; Sobolev, Victor S.

    2015-01-01

    The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That represents 100 million tons of food being destroyed or diverted to non-human consumption each year. Aflatoxins are powerful carcinogens normally accumulated by the fungi Aspergillus flavus and A. parasiticus in cereals, nuts, root crops and other agricultural products. Silencing of five aflatoxin-synthesis genes by RNA interference (RNAi) in peanut plants was used to control aflatoxin accumulation following inoculation with A. flavus. Previously, no method existed to analyze the effectiveness of RNAi in individual peanut transgenic events, as these usually produce few seeds, and traditional methods of large field experiments under aflatoxin-conducive conditions were not an option. In the field, the probability of finding naturally contaminated seeds is often 1/100 to 1/1,000. In addition, aflatoxin contamination is not uniformly distributed. Our method uses few seeds per transgenic event, with small pieces processed for real-time PCR (RT-PCR) or small RNA sequencing, and for analysis of aflatoxin accumulation by ultra-performance liquid chromatography (UPLC). RNAi-expressing peanut lines 288-72 and 288-74, showed up to 100% reduction (p≤0.01) in aflatoxin B1 and B2 compared to the control that accumulated up to 14,000 ng.g-1 of aflatoxin B1 when inoculated with aflatoxigenic A. flavus. As reference, the maximum total of aflatoxins allowable for human consumption in the United States is 20 ng.g-1. This protocol describes the application of RNAi-mediated control of aflatoxins in transgenic peanut seeds and methods for its evaluation. We believe that its application in breeding of peanut and other crops will bring rapid advancement in this important area of science, medicine and human nutrition, and will significantly contribute to the international effort to control aflatoxins, and potentially other mycotoxins in major

  20. Effects of temperature and medium composition on inhibitory activities of gossypol-related compounds against aflatoxigenic fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of temperature and medium composition on growth/aflatoxin inhibitory activities of gossypol, gossypolone and apogossypolone against Aspergillus flavus and A. parasiticus were investigated. The compounds were tested in a Czapek agar medium at 25 C, 31 C and 37 C at a concentration of 100 µg ...

  1. Biocontrol of Aspergillus flavus by Pichia anomala

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are extremely potent natural carcinogens and a major food safety concern because of potential contamination of food commodities. Threshold levels set by the U. S. Food and Drug Administration for aflatoxins in foods for domestic consumption are less than 20 parts/ billion (ppb). However, ...

  2. Detection and quantification of Aspergillus section Flavi spp. in stored peanuts by real-time PCR of nor-1 gene, and effects of storage conditions on aflatoxin production.

    PubMed

    Passone, María Alejandra; Rosso, Laura Cristina; Ciancio, Aurelio; Etcheverry, Miriam

    2010-04-15

    Aspergillus flavus and A. parasiticus are the main species from section Flavi responsible for aflatoxin accumulation in stored peanuts. A real-time PCR (RT-PCR) system directed against the nor-1 gene of the aflatoxin biosynthetic pathway as target sequence was applied to monitor and quantify Aspergillus section Flavi population in peanuts. Kernels were conditioned at four water activity (a(W)) levels and stored during a 4-month period. The quantification of fungal genomic DNA in naturally contaminated peanut samples was performed using TaqMan fluorescent probe technology. Sensitivity tests demonstrated that DNA amounts accounting for a single conidium of A. parasiticus RCP08300 can be detected. A standard curve relating nor-1 copy numbers to colony forming units (cfu) was constructed. Counts of species of Aspergillus section Flavi from unknown samples obtained by molecular and conventional count (CC) methodologies were compared. A correlation between cfu data obtained by RT-PCR and CC methods was observed (r=0.613; p<0.0001); and the former always showed values higher by 0.5-1 log units. A decrease of fungal density was observed throughout the storage period, regardless of the quantification methodology applied. Total aflatoxin levels ranging from 1.1 to 200.4 ng/g were registered in peanuts conditioned at the higher a(W) values (0.94-0.84 a(W)). The RT-PCR assay developed appears to be a promising tool in the prediction of potential aflatoxigenic risk in stored peanuts, even in case of low-level infections, and suitable for rapid, automated and high throughput analysis.

  3. Sex and recombination in aflatoxigenic Aspergilli: global implications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For most of the half century that aflatoxigenic species have been intensively studied, these molds were known only to reproduce asexually, with parasexuality found only in the laboratory between certain mutant strains. Therefore, the fairly recent discovery of their sexual (teleomorphic) states crea...

  4. Genetic diversity of Aspergillus species isolated from onychomycosis and Aspergillus hongkongensis sp. nov., with implications to antifungal susceptibility testing.

    PubMed

    Tsang, Chi-Ching; Hui, Teresa W S; Lee, Kim-Chung; Chen, Jonathan H K; Ngan, Antonio H Y; Tam, Emily W T; Chan, Jasper F W; Wu, Andrea L; Cheung, Mei; Tse, Brian P H; Wu, Alan K L; Lai, Christopher K C; Tsang, Dominic N C; Que, Tak-Lun; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

    2016-02-01

    Thirteen Aspergillus isolates recovered from nails of 13 patients (fingernails, n=2; toenails, n=11) with onychomycosis were characterized. Twelve strains were identified by multilocus sequencing as Aspergillus spp. (Aspergillus sydowii [n=4], Aspergillus welwitschiae [n=3], Aspergillus terreus [n=2], Aspergillus flavus [n=1], Aspergillus tubingensis [n=1], and Aspergillus unguis [n=1]). Isolates of A. terreus, A. flavus, and A. unguis were also identifiable by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The 13th isolate (HKU49(T)) possessed unique morphological characteristics different from other Aspergillus spp. Molecular characterization also unambiguously showed that HKU49(T) was distinct from other Aspergillus spp. We propose the novel species Aspergillus hongkongensis to describe this previously unknown fungus. Antifungal susceptibility testing showed most Aspergillus isolates had low MICs against itraconazole and voriconazole, but all Aspergillus isolates had high MICs against fluconazole. A diverse spectrum of Aspergillus species is associated with onychomycosis. Itraconazole and voriconazole are probably better drug options for Aspergillus onychomycosis.

  5. The population dynamics of aflatoxigenic aspergilli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the early eighteenth century, P.A. Micheli characterized the genus Aspergillus as an asexually reproducing species. Nearly a century later the first teleomorph was discovered and identified. Though other teleomorphs have been identified since Eurotium herbariorum (anamorph = A. glaucus), the ge...

  6. Potential of Aqueous Ozone to Control Aflatoxigenic Fungi in Brazil Nuts

    PubMed Central

    Morales-Valle, Héctor; Venâncio, Armando

    2013-01-01

    This study aimed to verify the use of aqueous ozone as alternative technology for fungal control. Brazil nuts sterilized were inoculated with either 1 × 106 or 1 × 107 conidia mL−1 of Aspergillus flavus (MUM 9201) to determine optimal treatment parameters and different aqueous ozone contact times. These assays showed that the effect of ozone is almost immediate against A. flavus, and the optimum ozone concentration depended on the number of initial viable spores on the shell. The remaining viable spores in the ozone solution were recorded, and the rate of inactivation for each treatment was determined by assessing the ratio between the cfu of each treatment and the control. The ozonized nuts were also cultured to recover the fungal population. Aqueous ozone was effective in reducing the conidia of A. flavus and the natural fungal population associated with Brazil nuts. Aqueous ozone presented a great potential to reduce microorganisms counts in Brazil nuts with a great potential use in packing houses for decontamination step. PMID:25937982

  7. High sequence variations in the region containing genes encoding a cellular morphogenesis protein and the repressor of sexual development help to reveal origins of Aspergillus oryzae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus oryzae and Aspergillus flavus are closely related fungal species. The A. flavus population that produces numerous small sclerotia (S strain) and aflatoxin has a unique 1.5 kb deletion in the norB-cypA region of the aflatoxin gene cluster (the S genotype). Phylogenetic studies have indica...

  8. A study on Aspergillus species in houses of asthmatic patients from Sari City, Iran and a brief review of the health effects of exposure to indoor Aspergillus.

    PubMed

    Hedayati, Mohammad T; Mayahi, Sabah; Denning, David W

    2010-09-01

    To study the distribution of Aspergillus spp. in outdoor and indoor air of asthmatic patients' houses, as well as a review on the health effects of exposure to indoor Aspergillus. Open plates containing malt extract agar media were used to isolate fungi from the indoor (n = 360) and outdoor (n = 180) air of 90 asthmatic patients' houses living in Sari City, Iran. Plates were incubated at room temperature for 7-14 days. Cultured Aspergillus spp. were identified by standard mycological techniques. All culture plates grew fungi, a testament to the ubiquitous nature of fungal exposure. Cladosporium spp. (29.2%), Aspergillus spp. (19.0%), and Penicillium spp. (18.3%) were most common inside the houses while Cladosporium spp. (44.5%), Aspergillus spp. (12.4%), and Alternaria spp. (11.1%) were most common outside the houses. Aspergillus flavus (30.1%) and A. fumigatus (23.1%) are the most commonly isolated species in indoor air. Aspergillus flavus (44.5%) and A. fumigatus (42.6%) were the most prevalent Aspergillus spp. outside. The most colony numbers of Aspergillus were isolated from kitchens (30.4%) and the least from bedrooms (21.1%). Aspergillus flavus was the most prevalent species in all sampled rooms except in the kitchen where A. fumigatus was the most common. Aspergillus flavus is the most prevalent species among the Aspergillus spp. in the indoor and outdoor of a warm climate area. In these areas, A. flavus can be a major source of allergen in the air. Therefore, minimizing indoor fungal exposure could play an important role in reducing allergic symptoms in susceptible persons.

  9. Septic arthritis due to tubercular and Aspergillus co-infection

    PubMed Central

    Kumar, Mukesh; Thilak, Jai; Zahoor, Adnan; Jyothi, Arun

    2016-01-01

    Aspergillus septic arthritis is a rare and serious medical and surgical problem. It occurs mainly in immunocompromised patients. Aspergillus fumigatus is the most common causative organism followed by Aspergillus flavus. The most common site affected is knee followed by shoulder, ankle, wrist, hip and sacroiliac joint. Debridement and voriconazole are primary treatment of articular aspergilosis. To the best of our knowledge, there are no reported cases of co-infection of tuberculosis (TB) and Aspergillus infecting joints. We report a case of co-infection of TB and A. flavus of hip and knee of a 60-year-old male, with type 2 diabetes mellitus. He was treated with debridement, intravenous voriconazole, and antitubercular drugs. PMID:27293296

  10. The distribution of Aspergillus spp. opportunistic parasites in hives and their pathogenicity to honey bees.

    PubMed

    Foley, Kirsten; Fazio, Géraldine; Jensen, Annette B; Hughes, William O H

    2014-03-14

    Stonebrood is a disease of honey bee larvae caused by fungi from the genus Aspergillus. As very few studies have focused on the epidemiological aspects of stonebrood and diseased brood may be rapidly discarded by worker bees, it is possible that a high number of cases go undetected. Aspergillus spp. fungi are ubiquitous and associated with disease in many insects, plants, animals and man. They are regarded as opportunistic pathogens that require immunocompromised hosts to establish infection. Microbiological studies have shown high prevalences of Aspergillus spp. in apiaries which occur saprophytically on hive substrates. However, the specific conditions required for pathogenicity to develop remain unknown. In this study, an apiary was screened to determine the prevalence and diversity of Aspergillus spp. fungi. A series of dose-response tests were then conducted using laboratory reared larvae to determine the pathogenicity and virulence of frequently occurring isolates. The susceptibility of adult worker bees to Aspergillus flavus was also tested. Three isolates (A. flavus, Aspergillus nomius and Aspergillus phoenicis) of the ten species identified were pathogenic to honey bee larvae. Moreover, adult honey bees were also confirmed to be highly susceptible to A. flavus infection when they ingested conidia. Neither of the two Aspergillus fumigatus strains used in dose-response tests induced mortality in larvae and were the least pathogenic of the isolates tested. These results confirm the ubiquity of Aspergillus spp. in the apiary environment and highlight their potential to infect both larvae and adult bees.

  11. Distribution and Toxigenicity of Aspergillus Species Isolated from Maize Kernels from Three Agro-ecological Zones in Nigeria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize samples were collected during a survey in three agro-ecological zones in Nigeria to determine the distribution and aflatoxin-producing potential of members of Aspergillus section Flavi. Among Aspergillus, A. flavus was the most predominant and L-strains constituted > 90% of the species identi...

  12. Toxigenic Aspergillus and Penicillium isolates from weevil-damaged chestnuts.

    PubMed

    Wells, J M; Payne, J A

    1975-10-01

    Aspergillus and Penicillium were among the most common genera of fungi isolated on malt-salt agar from weevil-damaged Chinese chestnut kernels (16.8 and 40.7% occurrence, respectively). Chloroform extracts of 21 of 50 Aspergillus isolates and 18 of 50 representative Penicillium isolates, grown for 4 weeks at 21.1 C on artificial medium, were toxic to day-old cockerels. Tweleve of the toxic Aspergillus isolates were identified as A. wentii, eight as A. flavus, and one as A. flavus var. columnaris. Nine of the toxic Penicillium isolates were identified as P. terrestre, three as P. steckii, two each as P. citrinum and P. funiculosum, and one each as P. herquei (Series) and P. roqueforti (Series). Acute diarrhea was associated with the toxicity of A. wentii and muscular tremors with the toxicity of P. terrestre, one isolate of P. steckii, and one of P. funiculosum.

  13. Draft genome sequences of two closely-related aflatoxigenic Aspergillus species obtained from the Ivory Coast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genomes of the A. ochraceoroseus and A. rambellii type strains were sequenced using a personal genome machine, followed by annotation of their genes. The genome size for A. ochraceoroseus was found to be approximately 23 Mb and contained 7,837 genes, while the A. rambellii genome was found to be...

  14. Rapid Differentiation of Aspergillus Species from Other Medically Important Opportunistic Molds and Yeasts by PCR-Enzyme Immunoassay

    PubMed Central

    de Aguirre, Liliana; Hurst, Steven F.; Choi, Jong Soo; Shin, Jong Hee; Hinrikson, Hans Peter; Morrison, Christine J.

    2004-01-01

    We developed a PCR-based assay to differentiate medically important species of Aspergillus from one another and from other opportunistic molds and yeasts by employing universal, fungus-specific primers and DNA probes in an enzyme immunoassay format (PCR-EIA). Oligonucleotide probes, directed to the internal transcribed spacer 2 region of ribosomal DNA from Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus terreus, Aspergillus ustus, and Aspergillus versicolor, differentiated 41 isolates (3 to 9 each of the respective species; P < 0.001) in a PCR-EIA detection matrix and gave no false-positive reactions with 33 species of Acremonium, Exophiala, Candida, Fusarium, Mucor, Paecilomyces, Penicillium, Rhizopus, Scedosporium, Sporothrix, or other aspergilli tested. A single DNA probe to detect all seven of the most medically important Aspergillus species (A. flavus, A. fumigatus, A. nidulans, A. niger, A. terreus, A. ustus, and A. versicolor) was also designed. Identification of Aspergillus species was accomplished within a single day by the PCR-EIA, and as little as 0.5 pg of fungal DNA could be detected by this system. In addition, fungal DNA extracted from tissues of experimentally infected rabbits was successfully amplified and identified using the PCR-EIA system. This method is simple, rapid, and sensitive for the identification of medically important Aspergillus species and for their differentiation from other opportunistic fungi. PMID:15297489

  15. Air-borne fungi in the air of Barcelona (Spain). III. The genus Aspergillus Link.

    PubMed

    Calvo, A; Guarro, J; Suarez, G; Ramirez, C

    1980-05-01

    During a survey on the presence of species of the genus Aspergillus in the air of the city of Barcelona (Spain), the following species were identified: Aspergillus flavus Link, A. niger van Tieghem, A. fumigatus Fresenius, A. clavatus Desmazières, A. terreus Thom, A. chevalieri (Mang.) Thom et Church, A. niveus Bloch, emend. Thom et Church, A. ochraceus Wilhelm, A. versicolor (Vuillemin) Tiraboschi, and A. amstelodami (Mang.) Church et Thom.

  16. Functional and phylogenetic analysis of the Aspergillus ochraceoroseus aflQ (ordA) gene ortholog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Within the Aspergillus parasiticus and A. flavus aflatoxin (AF) biosynthetic gene cluster the aflQ (ordA) and aflP (omtA) genes encode an oxidoreductase and methyltransferase, respectively. These genes are required for the final steps in the conversion of sterigmatocystin (ST) to aflatoxin B1 (AFB1...

  17. Understanding Nonaflatoxigenicity of Aspergillus sojae: A Windfall of Aflatoxin Biosynthesis Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus section Flavi includes aflatoxin-producing and nonproducing fungi. A. sojae is unable to produce aflatoxins and is generally recognized as safe for food fermentation. However, because of its taxonomical relatedness to aflatoxin-producing A. parasiticus and A. flavus, it is necessary to...

  18. Allergens/Antigens, toxins and polyketides of important Aspergillus species.

    PubMed

    Bhetariya, Preetida J; Madan, Taruna; Basir, Seemi Farhat; Varma, Anupam; Usha, Sarma P

    2011-04-01

    The medical, agricultural and biotechnological importance of the primitive eukaryotic microorganisms, the Fungi was recognized way back in 1920. Among various groups of fungi, the Aspergillus species are studied in great detail using advances in genomics and proteomics to unravel biological and molecular mechanisms in these fungi. Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus nidulans and Aspergillus terreus are some of the important species relevant to human, agricultural and biotechnological applications. The potential of Aspergillus species to produce highly diversified complex biomolecules such as multifunctional proteins (allergens, antigens, enzymes) and polyketides is fascinating and demands greater insight into the understanding of these fungal species for application to human health. Recently a regulator gene for secondary metabolites, LaeA has been identified. Gene mining based on LaeA has facilitated new metabolites with antimicrobial activity such as emericellamides and antitumor activity such as terrequinone A from A. nidulans. Immunoproteomic approach was reported for identification of few novel allergens for A. fumigatus. In this context, the review is focused on recent developments in allergens, antigens, structural and functional diversity of the polyketide synthases that produce polyketides of pharmaceutical and biological importance. Possible antifungal drug targets for development of effective antifungal drugs and new strategies for development of molecular diagnostics are considered.

  19. Isolation and characterization of Aspergillus parasiticus mutants with impaired aflatoxin production by a novel tip culture method.

    PubMed Central

    Yabe, K; Nakamura, H; Ando, Y; Terakado, N; Nakajima, H; Hamasaki, T

    1988-01-01

    A convenient procedure consisting of UV photography (K. Yabe, Y. Ando, M. Ito, and N. Terakado, Appl. Environ. Microbiol. 53:230-234, 1987) and a tip culture method has been devised for the isolation and characterization of Aspergillus parasiticus mutants relating to aflatoxin production. With the latter procedure, the production of aflatoxins excreted into the culture medium and precursors in the mycelium were easily measured quantitatively or semiquantitatively. A total of 38 mutants in which the aflatoxigenicity was decreased or lost were obtained by UV radiation; 3 were found to be blocked mutants, which accumulated the aflatoxin precursors versicolorin A or averantin. Images PMID:3178213

  20. Microclimatic conditions of Lasius flavus ant mounds

    NASA Astrophysics Data System (ADS)

    Véle, Adam; Holuša, Jaroslav

    2016-11-01

    Like other organisms, ants require suitable microclimatic conditions for their development. Thus, ant species inhabiting colder climates build nest mounds that rise above the soil surface, presumably to obtain heating from solar radiation. Although some ant species construct mounds of organic materials, which generate substantial heat due to microbial metabolism, Lasius flavus mounds consists mostly of soil, not organic material. The use of artificial shading in the current study demonstrated that L. flavus depends on direct solar radiation to regulate the temperature in its mound-like nests. Temperatures were much lower in shaded mounds than in unshaded mounds and were likely low enough in shaded mounds to reduce ant development and reproduction. In areas where L. flavus and similar ants are undesirable, they might be managed by shading.

  1. Microclimatic conditions of Lasius flavus ant mounds.

    PubMed

    Véle, Adam; Holuša, Jaroslav

    2016-11-23

    Like other organisms, ants require suitable microclimatic conditions for their development. Thus, ant species inhabiting colder climates build nest mounds that rise above the soil surface, presumably to obtain heating from solar radiation. Although some ant species construct mounds of organic materials, which generate substantial heat due to microbial metabolism, Lasius flavus mounds consists mostly of soil, not organic material. The use of artificial shading in the current study demonstrated that L. flavus depends on direct solar radiation to regulate the temperature in its mound-like nests. Temperatures were much lower in shaded mounds than in unshaded mounds and were likely low enough in shaded mounds to reduce ant development and reproduction. In areas where L. flavus and similar ants are undesirable, they might be managed by shading.

  2. Population structure and aflatoxin production by Aspergillus Sect. Flavi from maize in Nigeria and Ghana.

    PubMed

    Perrone, Giancarlo; Haidukowski, Miriam; Stea, Gaetano; Epifani, Filomena; Bandyopadhyay, Ranajit; Leslie, John F; Logrieco, Antonio

    2014-08-01

    Aflatoxins are highly toxic carcinogens that contaminate crops worldwide. Previous studies conducted in Nigeria and Ghana found high concentrations of aflatoxins in pre- and post-harvest maize. However, little information is available on the population structure of Aspergillus Sect. Flavi in West Africa. We determined the incidence of Aspergillus Sect. Flavi and the level of aflatoxin contamination in 91 maize samples from farms and markets in Nigeria and Ghana. Aspergillus spp. were recovered from 61/91 maize samples and aflatoxins B1 and/or B2 occurred in 36/91 samples. Three samples from the farms also contained aflatoxin G1 and/or G2. Farm samples were more highly contaminated than were samples from the market, in terms of both the percentage of the samples contaminated and the level of mycotoxin contamination. One-hundred-and-thirty-five strains representative of the 1163 strains collected were identified by using a multilocus sequence analysis of portions of the genes encoding calmodulin, β-tubulin and actin, and evaluated for aflatoxin production. Of the 135 strains, there were 110 - Aspergillus flavus, 20 - Aspergillus tamarii, 2 - Aspergillus wentii, 2 - Aspergillus flavofurcatus, and 1 - Aspergillus parvisclerotigenus. Twenty-five of the A. flavus strains and the A. parvisclerotigenus strain were the only strains that produced aflatoxins. The higher contamination of the farm than the market samples suggests that the aflatoxin exposure of rural farmers is even higher than previously estimated based on reported contamination of market samples. The relative infrequency of the A. flavus SBG strains, producing small sclerotia and high levels of both aflatoxins (B and G), suggests that long-term chronic exposure to this mycotoxin are a much higher health risk in West Africa than is the acute toxicity due to very highly contaminated maize in east Africa.

  3. Use of benzo analogs to enhance antimycotic activity of kresoxim methyl for control of aflatoxigenic fungal pathogens

    PubMed Central

    Kim, Jong H.; Mahoney, Noreen; Chan, Kathleen L.; Campbell, Bruce C.; Haff, Ronald P.; Stanker, Larry H.

    2014-01-01

    The aim of this study was to examine two benzo analogs, octylgallate (OG) and veratraldehyde (VT), as antifungal agents against strains of Aspergillus parasiticus and A.flavus (toxigenic or atoxigenic). Both toxigenic and atoxigenic strains used were capable of producing kojic acid, another cellular secondary product. A. fumigatus was used as a genetic model for this study. When applied independently, OG exhibits considerably higher antifungal activity compared to VT. The minimum inhibitory concentrations (MICs) of OG were 0.3–0.5 mM, while that of VT were 3.0–5.0 mM in agar plate-bioassays. OG or VT in concert with the fungicide kresoxim methyl (Kre-Me; strobilurin) greatly enhanced sensitivity of Aspergillus strains to Kre-Me. The combination with OG also overcame the tolerance of A. fumigatus mitogen-activated protein kinase (MAPK) mutants to Kre-Me. The degree of compound interaction resulting from chemosensitization of the fungi by OG was determined using checkerboard bioassays, where synergistic activity greatly lowered MICs or minimum fungicidal concentrations. However, the control chemosensitizer benzohydroxamic acid, an alternative oxidase inhibitor conventionally applied in concert with strobilurin, did not achieve synergism. The level of antifungal or chemosensitizing activity was also “compound—strain” specific, indicating differential susceptibility of tested strains to OG or VT, and/or heat stress. Besides targeting the antioxidant system, OG also negatively affected the cell wall-integrity pathway, as determined by the inhibition of Saccharomyces cerevisiae cell wall-integrity MAPK pathway mutants. We concluded that certain benzo analogs effectively inhibit fungal growth. They possess chemosensitizing capability to increase efficacy of Kre-Me and thus, could reduce effective dosages of strobilurins and alleviate negative side effects associated with current antifungal practices. OG also exhibits moderate antiaflatoxigenic activity. PMID

  4. Metabolomics Analysis Reveals Specific Novel Tetrapeptide and Potential Anti-Inflammatory Metabolites in Pathogenic Aspergillus species

    PubMed Central

    Lee, Kim-Chung; Tam, Emily W. T.; Lo, Ka-Ching; Tsang, Alan K. L.; Lau, Candy C. Y.; To, Kelvin K. W.; Chan, Jasper F. W.; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K. P.; Woo, Patrick C. Y.

    2015-01-01

    Infections related to Aspergillus species have emerged to become an important focus in infectious diseases, as a result of the increasing use of immunosuppressive agents and high fatality associated with invasive aspergillosis. However, laboratory diagnosis of Aspergillus infections remains difficult. In this study, by comparing the metabolomic profiles of the culture supernatants of 30 strains of six pathogenic Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, A. nomius and A. tamarii) and 31 strains of 10 non-Aspergillus fungi, eight compounds present in all strains of the six Aspergillus species but not in any strain of the non-Aspergillus fungi were observed. One of the eight compounds, Leu–Glu–Leu–Glu, is a novel tetrapeptide and represents the first linear tetrapeptide observed in Aspergillus species, which we propose to be named aspergitide. Two other closely related Aspergillus-specific compounds, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid, may possess anti-inflammatory properties, as 2-(sulfooxy)benzoic acid possesses a structure similar to those of aspirin [2-(acetoxy)benzoic acid] and salicylic acid (2-hydroxybenzoic acid). Further studies to examine the potentials of these Aspergillus-specific compounds for laboratory diagnosis of aspergillosis are warranted and further experiments will reveal whether Leu–Glu–Leu–Glu, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid are virulent factors of the pathogenic Aspergillus species. PMID:26090713

  5. In vitro susceptibilities of Aspergillus spp. causing otomycosis to amphotericin B, voriconazole and itraconazole.

    PubMed

    Kaya, Ayse Demet; Kiraz, Nuri

    2007-11-01

    Otomycosis is worldwide in distribution and most commonly caused by Aspergillus species. Amphotericin B, itraconazole and voriconazole are used for the treatment of aspergillosis, but recently an increase in resistance to these agents has been reported. We aimed at investigating the in vitro activities of amphotericin B, voriconazole and itraconazole against Aspergillus isolates causing otomycosis. Mycological analysis of samples from the ear canals of patients was performed by culturing onto Sabouraud Dextrose Agar and by evaluating microscopically. Aspergillus species were identified with colony morphology and microscopic appearance, and tested for susceptibilities to amphotericin B, itraconazole and voriconazole by the CLSI reference broth microdilution method (M38-A document). A total of 120 isolates from 120 patients, comprising 57 Aspergillus niger, 42 Aspergillus fumigatus, nine Aspergillus flavus, six Aspergillus nidulans and six Aspergillus terreus strains were tested. No resistance was determined against amphotericin B and voriconazole, while six A. fumigatus and three A. niger isolates were resistant to itraconazole. In vitro data obtained in this study showed the resistance to itraconazole, while all of the isolates were susceptible to voriconazole and amphotericin B. Voriconazole seemed to be an alternative in the treatment of infections related to Aspergillus spp. but further studies are needed to learn more about the antifungal resistance of different species of Aspergillus to different agents.

  6. 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...

  7. DOPA and DHN pathway orchestrate melanin synthesis in Aspergillus species.

    PubMed

    Pal, Anuradha K; Gajjar, Devarshi U; Vasavada, Abhay R

    2014-01-01

    Melanins are high molecular weight hydrophobic pigments that have been studied for their role in the virulence of fungal pathogens. We investigated the amount and type of melanin in 20 isolates of Aspergillus spp.; A. niger (n = 3), A. flavus (n = 5), A. tamarii (n = 3), A. terreus (n = 3), A. tubingensis (n = 3), A. sydowii (n = 3). Aspergillus spp. were identified by sequencing the internal transcribed spacer (ITS) region. Extraction of melanin from culture filtrate and fungal biomass was done and followed by qualitative and quantitative analysis of melanin pigment. Ultraviolet (UV), Fourier transformed infrared (FT-IR), and electron paramagnetic resonance (EPR) spectra analyses confirmed the presence of melanin. The melanin pathway was studied by analyzing the effects of inhibitors; kojic acid, tropolone, phthalide, and tricyclazole. The results indicate that in A. niger and A. tubingensis melanin was found in both culture filtrate and fungal biomass. For A. tamarii and A. flavus melanin was extracted from biomass only, whereas melanin was found only in culture filtrate for A. terreus. A negligible amount of melanin was found in A. sydowii. The maximum amount of melanin from culture filtrate and fungal biomass was found in A. niger and A. tamarrii, respectively. The DOPA (3,4-dihydroxyphenylalanine) pathway produces melanin in A. niger, A. tamarii and A. flavus, whereas the DHN (1,8-dihydroxynaphthalene) pathway produces melanin in A. tubingensis and A. terreus. It can be concluded that the amount and type of melanin in aspergilli largely differ from species to species.

  8. Characterization of filamentous fungi isolated from Moroccan olive and olive cake: toxinogenic potential of Aspergillus strains.

    PubMed

    Roussos, Sevastianos; Zaouia, Nabila; Salih, Ghislane; Tantaoui-Elaraki, Abdelrhafour; Lamrani, Khadija; Cheheb, Mostafa; Hassouni, Hicham; Verhé, Fréderic; Perraud-Gaime, Isabelle; Augur, Christopher; Ismaili-Alaoui, Mustapha

    2006-05-01

    During the 2003 and 2004 olive oil production campaigns in Morocco, 136 samples from spoiled olive and olive cake were analyzed and 285 strains were isolated in pure culture. Strains included 167 mesophilic strains belonging to ten genera: Penicillium, Aspergillus, Geotrichum, Mucor, Rhizopus, Trichoderma, Alternaria, Acremonium, Humicola, Ulocladium as well as 118 thermophilic strains isolated in 2003 and 2004, mainly belonging to six species: Aspergillus fumigatus, Paecilomyces variotii, Mucor pusillus, Thermomyces lanuginosus, Humicola grisea, and Thermoascus aurantiacus. Penicillium and Aspergillus, respectively, 32.3 and 26.9% of total isolates represented the majority of mesophilic fungi isolated. When considering total strains (including thermotolerant strains) Aspergillus were the predominant strains isolated; follow-up studies on mycotoxins therefore focused primarily on aflatoxins (AFs) and ochratoxin A (OTA) from the latter strains. All isolated Aspergillus flavus strains (9) and Aspergillus niger strains (36) were studied in order to evaluate their capacity to produce AFs and OTA, respectively, when grown on starch-based culture media. Seven of the nine tested A. flavus strains isolated from olive and olive cake produced AF B1 at concentrations between 48 and 95 microg/kg of dry rice weight. As for the A. niger strains, 27 of the 36 strains produced OTA.

  9. Bioleaching of serpentine group mineral by fungus Talaromyces flavus: application for mineral carbonation

    NASA Astrophysics Data System (ADS)

    Li, Z.; Lianwen, L.; Zhao, L.; Teng, H.

    2011-12-01

    Many studies of serpentine group mineral dissolution for mineral carbonation have been published in recent years. However, most of them focus mainly on either physical and chemical processes or on bacterial function, rather than fungal involvement in the bioleaching of serpentine group mineral. Due to the excessive costs of the magnesium dissolution process, finding a lower energy consumption method will be meaningful. A fungal strain Talaromyces flavus was isolated from serpentinic rock of Donghai (China). No study of its bioleaching ability is currently available. It is thus of great significance to explore the impact of T. flavus on the dissolution of serpentine group mineral. Serpentine rock-inhabiting fungi belonging to Acremonium, Alternaria, Aspergillus, Botryotinia, Cladosporium, Clavicipitaceae, Cosmospora, Fusarium, Monascus, Paecilomyces, Penicillium, Talaromyces, Trichoderma were isolated. These strains were chosen on the basis of resistance to magnesium and nickel characterized in terms of minimum inhibiting concentration (MIC). Specifically, the strain Talaromyces flavus has a high tolerance to both magnesium (1 mol/L) and nickel (10 mM/L), and we examine its bioleaching ability on serpentine group mineral. Contact and separation experiments (cut-off 8 000-14 000 Da), as well as three control experiments, were set up for 30 days. At least three repeated tests were performed for each individual experiment. The results of our experiments demonstrate that the bioleaching ability of T. flavus towards serpentine group mineral is evident. 39.39 wt% of magnesium was extracted from lizardite during the bioleaching period in the contact experiment, which showed a dissolution rate at about a constant 0.126 mM/d before reaching equilibrium in 13 days. The amount of solubilized Mg from chrysotile and antigorite were respectively 37.79 wt% and 29.78 wt% in the contact experiment. These results make clear the influence of mineral structure on mineral bioleaching

  10. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species.

    PubMed

    Zomorodian, Kamiar; Pourshahid, Seyedmohammad; Sadatsharifi, Arman; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity.

  11. In vitro activity of disinfectants against Aspergillus spp

    PubMed Central

    Mattei, A.S.; Madrid, I.M.; Santin, R.; Schuch, L.F.D.; Meireles, M.C.A.

    2013-01-01

    Fungi of the Aspergillus genus are widespread and contaminate the environment. Thousands of conidia are released from each phialide and dispersed in the air every day. These fungi are considered important mycose-causing agents in hospitals. Due to this, research to determine prevalent fungi from the Aspergillus genus in hospital environments, and an adequate disinfection program in these areas is are needed. This study evaluated the susceptibility of Aspergillus spp. isolated from a veterinary environment against four disinfectants. Successive dilutions of disinfectants (log2) were used according to CLSI M38-A2 microdilution technique adapted to chemical agents against 18 isolates of this genus. After 72 hours of incubation, the Minimum Inhibiting Concentration and Minimum Fungicidal Concentration capable of inhibiting 50% and 90% of the isolates were determined. Chlorexidine-cetrimine, benzalconium chloride and a chlorophenol derivative proved to be effective against all isolates with a lower MIC than that suggested by the manufacturer, except for the A. flavus strain. Sodium hypochlorite was ineffective against three A. fumigatus, three A. flavus and one A. niger isolate. These results demonstrated that all studied disinfectants were effective against environmental isolates, with the exception of sodium hypochlorite, which showed lower effectiveness. PMID:24294243

  12. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

    PubMed Central

    Pourshahid, Seyedmohammad; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity. PMID:27652264

  13. Aspergillus niger: an unusual cause of invasive pulmonary aspergillosis

    PubMed Central

    Person, A. K.; Chudgar, S. M.; Norton, B. L.; Tong, B. C.; Stout, J. E.

    2010-01-01

    Infections due to Aspergillus species cause significant morbidity and mortality. Most are attributed to Aspergillus fumigatus, followed by Aspergillus flavus and Aspergillus terreus. Aspergillus niger is a mould that is rarely reported as a cause of pneumonia. A 72-year-old female with chronic obstructive pulmonary disease and temporal arteritis being treated with steroids long term presented with haemoptysis and pleuritic chest pain. Chest radiography revealed areas of heterogeneous consolidation with cavitation in the right upper lobe of the lung. Induced bacterial sputum cultures, and acid-fast smears and cultures were negative. Fungal sputum cultures grew A. niger. The patient clinically improved on a combination therapy of empiric antibacterials and voriconazole, followed by voriconazole monotherapy. After 4 weeks of voriconazole therapy, however, repeat chest computed tomography scanning showed a significant progression of the infection and near-complete necrosis of the right upper lobe of the lung. Serum voriconazole levels were low–normal (1.0 μg ml−1, normal range for the assay 0.5–6.0 μg ml−1). A. niger was again recovered from bronchoalveolar lavage specimens. A right upper lobectomy was performed, and lung tissue cultures grew A. niger. Furthermore, the lung histopathology showed acute and organizing pneumonia, fungal hyphae and oxalate crystallosis, confirming the diagnosis of invasive A. niger infection. A. niger, unlike A. fumigatus and A. flavus, is less commonly considered a cause of invasive aspergillosis (IA). The finding of calcium oxalate crystals in histopathology specimens is classic for A. niger infection and can be helpful in making a diagnosis even in the absence of conidia. Therapeutic drug monitoring may be useful in optimizing the treatment of IA given the wide variations in the oral bioavailability of voriconazole. PMID:20299503

  14. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins

    PubMed Central

    Gong, An-Dong; Li, He-Ping; Shen, Lu; Zhang, Jing-Bo; Wu, Ai-Bo; He, Wei-Jie; Yuan, Qing-Song; He, Jing-De; Liao, Yu-Cai

    2015-01-01

    Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these microbes is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs) emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl)-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production during storage and possibly in the field. PMID:26500631

  15. Multilocus sequence analysis of Aspergillus Sect. Nigri in dried vine fruits of worldwide origin.

    PubMed

    Susca, Antonia; Perrone, Giancarlo; Cozzi, Giuseppe; Stea, Gaetano; Logrieco, Antonio F; Mulè, Giuseppina

    2013-07-15

    Dried vine fruits may be heavily colonized by Aspergillus species. The molecular biodiversity of an Aspergillus population (234 strains) isolated from dried vine fruit samples of worldwide origin were analyzed by investigating four housekeeping gene loci (calmodulin, β-tubulin, elongation factor 1-α, RPB2). Aspergillus Sect. Nigri was dominant and the strains were identified as A. tubingensis (138), A. awamori (38), A. carbonarius (27), A. uvarum (16) and A. niger (11). Four Aspergillus flavus strains were also identified from Chilean raisins. Two clusters closely related to the A. tubingensis species with a significant bootstrap (60% and 99%) were identified as distinct populations. Among the four loci, RPB2 showed the highest genetic variability. This is the first complete study on the worldwide distribution of black Aspergilli occurring on dried vine fruits identified by a molecular approach.

  16. The entomopathogenic potential of Aspergillus spp. in mosquitoes vectors of tropical diseases.

    PubMed

    de Moraes, A M; da Costa, G L; Barcellos, M Z; de Oliveira, R L; de Oliveira, P C

    2001-01-01

    Eleven strains of the most frequent Aspergillus species found in a survey of Brazilian mosquitoes collected in the states of Minas Gerais and Rio de Janeiro, Brazil, were used for bioassays in second-stage larvae of Aedes fluviatilis and Culex quinquefasciatus. Aspergillus ochraceus, A. kanagawaensis and one strain of A. sulphureus were most effective, causing mortality in at least 80% of the larvae of the two mosquito species tested. Variations in entomopathogenic capacity were observed in the experiments with strains of A. sulphureus, A. flavus and A. ochraceus.

  17. Aspergillus section Flavi and aflatoxins in Algerian wheat and derived products.

    PubMed

    Riba, Amar; Bouras, Noureddine; Mokrane, Salim; Mathieu, Florence; Lebrihi, Ahmed; Sabaou, Nasserdine

    2010-10-01

    Wheat and its derivatives are a very important staple food for North African populations. The aim of this study was to analyze populations of Aspergillus section Flavi from local wheat based on aflatoxins (AFs), cyclopiazonic acid (CPA) and sclerotia production, and also to evaluate AFs-contaminated wheat collected from two different climatic regions in Algeria. A total of 108 samples of wheat were collected during the following phases: pre-harvest, storage in silos and after processing. The results revealed that among the Aspergillus species isolated, those belonging to section Flavi were predominant. Of the 150 strains of Aspergillus section Flavi isolated, 144 were identified as Aspergillus flavus and 6 as Aspergillus tamarii. We showed that 72% and 10% of the A. flavus strains produced AFs and CPA, respectively. Among the 150 strains tested, 60 produced amounts of AFB1 ranging from 12.1 to 234.6 microg/g of CYA medium. Also, we showed that most strains produced large sclerotia. AFB1was detected by HPLC in 56.6% of the wheat samples and derived products (flour, semolina and bran) with contamination levels ranging from 0.13 to 37.42 microg/kg.

  18. Host-Induced Gene Silencing (HIGS) of aflatoxin synthesis genes in peanut and maize: use of RNA interference and genetic diversity of Aspergillus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Approximately 4.5 billion people are chronically exposed to aflatoxins, these are powerful carcinogens produced by Aspergillus flavus and A. parasiticus. High levels of aflatoxins in crops result in approximately 100 million metric tons of cereals, ¬nuts, root crops and other agricultural products ...

  19. Aflatoxin, Aspergillus, Maize, and the Relevance to Alternative Fuels (or Aflatoxin: What is It, Can We Get Rid of It, and Should the Ethanol Industry Care?)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The contamination of agricultural commodities by Aspergillus flavus and its subsequent production of aflatoxin is a well known problem. The resulting aflatoxin contamination if undetected results in fatal health issues for both man and animals. To prevent these effects regulatory limits on aflatox...

  20. New Additive for Culture Media for Rapid Identification of Aflatoxin-Producing Aspergillus Strains

    PubMed Central

    Fente, C. A.; Ordaz, J. Jaimez; Vázquez, B. I.; Franco, C. M.; Cepeda, A.

    2001-01-01

    A new reliable, fast, and simple method for the detection of aflatoxigenic Aspergillus strains, consisting of the addition of a cyclodextrin (a methylated β-cyclodextrin derivative) to common media used for testing mycotoxin production ability, was developed. We propose the use of this compound as an additive for fungal culture media to enhance the natural fluorescence of aflatoxins. The production of aflatoxins coincided with the presence of a bright blue or blue-green fluorescent area surrounding colonies when observed under long-wavelength (365-nm) UV light after 3 days of incubation at 28°C. The presence of aflatoxins was confirmed by extracting the medium with chloroform and examining the extracts by high-pressure liquid chromatography with fluorescence detection. PMID:11571194

  1. Development of RFLP-PCR method for the identification of medically important Aspergillus species using single restriction enzyme MwoI

    PubMed Central

    Diba, K.; Mirhendi, H.; Kordbacheh, P.; Rezaie, S.

    2014-01-01

    In this study we attempted to modify the PCR-RFLP method using restriction enzyme MwoI for the identification of medically important Aspergillus species. Our subjects included nine standard Aspergillus species and 205 Aspergillus isolates of approved hospital acquired infections and hospital indoor sources. First of all, Aspergillus isolates were identified in the level of species by using morphologic method. A twenty four hours culture was performed for each isolates to harvest Aspergillus mycelia and then genomic DNA was extracted using Phenol-Chloroform method. PCR-RFLP using single restriction enzyme MwoI was performed in ITS regions of rDNA gene. The electrophoresis data were analyzed and compared with those of morphologic identifications. Total of 205 Aspergillus isolates included 153 (75%) environmental and 52 (25%) clinical isolates. A. flavus was the most frequently isolate in our study (55%), followed by A. niger 65(31.7%), A. fumigatus 18(8.7%), A. nidulans and A. parasiticus 2(1% each). MwoI enabled us to discriminate eight medically important Aspergillus species including A. fumigatus, A. niger, A. flavus as the most common isolated species. PCR-RFLP method using the restriction enzyme MwoI is a rapid and reliable test for identification of at least the most medically important Aspergillus species. PMID:25242934

  2. What can comparative genomics tell us about species concepts in the genus Aspergillus?

    SciTech Connect

    Rokas, Antonis; payne, gary; Federova, Natalie D.; Baker, Scott E.; Machida, Masa; yu, Jiujiang; georgianna, D. R.; Dean, Ralph A.; Bhatnagar, Deepak; Cleveland, T. E.; Wortman, Jennifer R.; Maiti, R.; Joardar, V.; Amedeo, Paolo; Denning, David W.; Nierman, William C.

    2007-12-15

    Understanding the nature of species" boundaries is a fundamental question in evolutionary biology. The availability of genomes from several species of the genus Aspergillus allows us for the first time to examine the demarcation of fungal species at the whole-genome level. Here, we examine four case studies, two of which involve intraspecific comparisons, whereas the other two deal with interspecific genomic comparisons between closely related species. These four comparisons reveal significant variation in the nature of species boundaries across Aspergillus. For example, comparisons between A. fumigatus and Neosartorya fischeri (the teleomorph of A. fischerianus) and between A. oryzae and A. flavus suggest that measures of sequence similarity and species-specific genes are significantly higher for the A. fumigatus - N. fischeri pair. Importantly, the values obtained from the comparison between A. oryzae and A. flavus are remarkably similar to those obtained from an intra-specific comparison of A. fumigatus strains, giving support to the proposal that A. oryzae represents a distinct ecotype of A. flavus and not a distinct species. We argue that genomic data can aid Aspergillus taxonomy by serving as a source of novel and unprecedented amounts of comparative data, as a resource for the development of additional diagnostic tools, and finally as a knowledge database about the biological differences between strains and species.

  3. Evaluation of Chenopodium ambrosioides oil as a potential source of antifungal, antiaflatoxigenic and antioxidant activity.

    PubMed

    Kumar, Rajesh; Mishra, Ajay Kumar; Dubey, N K; Tripathi, Y B

    2007-04-10

    Essential oil extracted from the leaves of Chenopodium ambrosioides Linn. (Chenopodiaceae) was tested against the aflatoxigenic strain of test fungus Aspergillus flavus Link. The oil completely inhibited the mycelial growth at 100 microg/ml. The oil exhibited broad fungitoxic spectrum against Aspergillus niger, Aspergillus fumigatus, Botryodiplodia theobromae, Fusarium oxysporum, Sclerotium rolfsii, Macrophomina phaseolina, Cladosporium cladosporioides, Helminthosporium oryzae and Pythium debaryanum at 100 microg/ml. The oil showed significant efficacy in inhibiting the aflatoxin B1 production by the aflatoxigenic strain of A. flavus. During in vivo investigation it protected stored wheat from different storage fungi for one year. Chenopodium oil also exhibited potent antioxidant activity when tested by ABTS method. All these observations suggest the possible exploitation of the Chenopodium oil as potential botanical fungitoxicant in ecofriendly control of post harvest biodeterioration of food commodities from storage fungi.

  4. Detection of Aspergillus-specific antibodies by agar gel double immunodiffusion and IgG ELISA in feline upper respiratory tract aspergillosis.

    PubMed

    Barrs, V R; Ujvari, B; Dhand, N K; Peters, I R; Talbot, J; Johnson, L R; Billen, F; Martin, P; Beatty, J A; Belov, K

    2015-03-01

    Feline upper respiratory tract aspergillosis (URTA) is an emerging infectious disease. The aims of this study were: (1) to assess the diagnostic value of detection of Aspergillus-specific antibodies using an agar gel double immunodiffusion (AGID) assay and an indirect immunoglobulin G (IgG) ELISA; and (2) to determine if an aspergillin derived from mycelia of Aspergillus fumigatus, Aspergillus niger and Aspergillus flavus can be used to detect serum antibodies against cryptic Aspergillus spp. in Aspergillus section Fumigati. Sera from cats with URTA (group 1: n = 21) and two control groups (group 2: cats with other upper respiratory tract diseases, n = 25; group 3: healthy cats and cats with non-respiratory, non-fungal illness, n = 84) were tested. Isolates from cats with URTA comprised A. fumigatus (n = 5), A. flavus (n = 1) and four cryptic species: Aspergillus felis (n = 12), Aspergillus thermomutatus (Neosartorya pseudofischeri, n = 1), Aspergillus lentulus (n = 1) and Aspergillus udagawae (n = 1). Brachycephalic purebred cats were significantly more likely to develop URTA than other breeds (P = 0.013). The sensitivity (Se) of the AGID was 43% and the specificity (Sp) was 100%. At a cut-off value of 6 ELISA units/mL, the Se of the IgG ELISA was 95.2% and the Sp was 92% and 92.9% for groups 2 and 3 cats, respectively. Aspergillus-specific antibodies against all four cryptic species were detected in one or both assays. Assay Se was not associated with species identity. Detection of Aspergillus-specific antibodies by IgG ELISA has high Se and Sp for diagnosis of feline URTA.

  5. Fusarium and Aspergillus mycotoxins contaminating wheat silage for dairy cattle feeding in Uruguay.

    PubMed

    Del Palacio, Agustina; Bettucci, Lina; Pan, Dinorah

    Wheat is one of the most important cultivated cereals in Uruguay for human consumption; however, when harvest yields are low, wheat is usually used in ensiling for animal feeding. Ensiling is a forage preservation method that allows for storage during extended periods of time while maintaining nutritional values comparable to fresh pastures. Silage is vulnerable to contamination by spoilage molds and mycotoxins because ensilage materials are excellent substrates for fungal growth. The aim of the study was to identify the mycobiota composition and occurrence of aflatoxins and DON from wheat silage. A total of 220 samples of wheat were collected from four farms in the southwest region of Uruguay were silage practices are developed. The main fungi isolated were Fusarium (43%) and Aspergillus (36%), with Fusarium graminearum sensu lato and Aspergillus section Flavi being the most prevalent species. Aflatoxin concentrations in silo bags ranged from 6.1 to 23.3μg/kg, whereas DON levels ranged between 3000μg/kg and 12,400μg/kg. When evaluating aflatoxigenic capacity, 27.5% of Aspergillus section Flavi strains produced AFB1, 5% AFB2, 10% AFG1 and 17.5% AFG2. All isolates of F. graminearum sensu lato produced DON and 15-AcDON. The results from this study contribute to the knowledge of mycobiota and mycotoxins present in wheat silage.

  6. 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

    2014-11-13

    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.

  7. [Applications of molecular biology techniques for the control of aflatoxin contamination].

    PubMed

    Sanchis, V

    1993-02-01

    Aflatoxins are mycotoxins produced by species of Aspergillus flavus group. These toxins have received increased attention from the food industry and the general public because they shown a high toxicity against humans and animal. Different methods are applying to control the aflatoxin contamination. But these conventional methods do not seem to resolve the problem. So, new methods using techniques in biotechnology are now being developed: a) Inhibit the biosynthetic and secretory process responsible for aflatoxin contamination. b) Using biocompetitive agents that replace aflatoxigenic strains with non aflatoxigenic strains in the field. c) Using genetic engineering techniques to incorporate antifungal genes into specific plant species.

  8. Screening of Argentine plant extracts: impact on growth parameters and aflatoxin B1 accumulation by Aspergillus section Flavi.

    PubMed

    Bluma, R; Amaiden, M R; Etcheverry, M

    2008-02-29

    The effect of essential oils, ethanolic and aqueous extract of 41 vegetable species on Aspergillus section Flavi growth was evaluated. The in vitro screen was a two-stage process. A wide-spectrum initial screen which identified promising antifungal plant extracts was carried out first. After that, identified extracts were studied in more detail by in vitro assays. A total of 96 plant extracts were screened. Essential oils were found to be the most effective extract controlling aflatoxigenic strains. Clove, mountain thyme, poleo and eucalyptus essential oils were selected to study their antifungal effect. Studies on percentage of germination, germ-tube elongation rate, growth rate, and aflatoxin B1 accumulation were carried out. Clove, mountain thyme and poleo essential oils showed the most antifungal effect under all growth parameters analyzed as well as aflatoxin B1 accumulation. Our results suggest that mountain thyme and poleo, which are native vegetal species of Argentina, and clove essential oils could be used alone or in conjunction with other substances to control the presence of aflatoxigenic fungi in stored maize.

  9. Characterization of Aspergillus section Flavi isolated from organic Brazil nuts using a polyphasic approach.

    PubMed

    Reis, T A; Baquião, A C; Atayde, D D; Grabarz, F; Corrêa, B

    2014-09-01

    Brazil nut (Bertholletia excelsa), an important non-timber forest product from Amazonia, is commercialized in worldwide markets. The main importers of this nut are North America and European countries, where the demand for organic products has grown to meet consumers concerned about food safety. Thus, the precise identification of toxigenic fungi is important because the Brazil nut is susceptible to colonization by these microorganisms. The present study aimed to characterize by polyphasic approach strains of Aspergillus section Flavi from organic Brazil nuts. The results showed Aspergillus flavus as the main species found (74.4%), followed by Aspergillus nomius (12.7%). The potential mycotoxigenic revealed that 80.0% of A. flavus were toxin producers, 14.3% of which produced only aflatoxin B (AFB), 22.85% of which produced only cyclopiazonic acid (CPA), and 42.85% produced both them. All strains of A. nomius were AFB and AFG producers and did not produce CPA. There is no consensus about what Aspergillus species predominates on Brazil nuts. Apparently, the origin, processing, transport and storage conditions of this commodity influence the species that are found. The understanding about population of fungi is essential for the development of viable strategies to control aflatoxins in organic Brazil nuts.

  10. Effects of atmospheric pressure non-thermal plasma treatments on aflatoxigenic fungi and its host

    NASA Astrophysics Data System (ADS)

    Chen, Bo-Chen

    2015-09-01

    This experiment tests the ability of atmospheric pressure non-thermal plasma treatments in the prevention of fungi infection. There are charged particles, electric field, radicals and UV light inside plasmas and these elements might trigger different physical or chemical effects during non-thermal plasma treatments. In this experiment, the experimental samples received indirect plasma treatments with different time duration and gas compositions which mean only the remote effects caused by plasma treatments could be seen. In this work, plasmas were produced by dielectric barrier discharge method. The operation gases were air and a mixed gas of 97% He and 3%O2. After plasma treatments, fungi growth rate was observed by taking pictures and the existence of aflatoxin was qualitatively detected by black light method. The final results show that the radicals in both He/O2 and air plasma might facilitate fungi growth rate which means peanuts received indirect plasma treatments grew fungi faster than control group. The outcomes of aflatoxin detection also shows that the fungi grown on all the sample are aflatoxigenic fungi.

  11. Aspergillus spinal epidural abscess

    SciTech Connect

    Byrd, B.F. III; Weiner, M.H.; McGee, Z.A.

    1982-12-17

    A spinal epidural abscess developed in a renal transplant recipient; results of a serum radioimmunoassay for Aspergillus antigen were positive. Laminectomy disclosed an abscess of the L4-5 interspace and L-5 vertebral body that contained hyphal forms and from which Aspergillus species was cultured. Serum Aspergillus antigen radioimmunoassay may be a valuable, specific early diagnostic test when systemic aspergillosis is a consideration in an immunosuppressed host.

  12. Aspergillus spp. invasive external otitis: favourable outcome with a medical approach.

    PubMed

    Marchionni, E; Parize, P; Lefevre, A; Vironneau, P; Bougnoux, M E; Poiree, S; Coignard-Biehler, H; DeWolf, S E; Amazzough, K; Barchiesi, F; Jullien, V; Alanio, A; Garcia-Hermoso, D; Wassef, M; Kania, R; Lortholary, O; Lanternier, F

    2016-05-01

    Aspergillus spp. invasive external otitis (IEO) is a rare infection. We performed a seven-year, single-centre retrospective study from 2007 to 2014 including all patients with proven Aspergillus spp. IEO. Twelve patients were identified. All patients had a poorly controlled diabetes mellitus and one underwent solid organ transplant. The most frequently isolated species was Aspergillus flavus (n = 10) and voriconazole was the first-line therapy in all cases, with a median length of treatment of 338.5 days (158-804 days). None of the patients underwent extensive surgery. The clinical outcome was excellent. However, otological sequelae were reported, including hearing impairment (n = 7) and facial palsy (n = 3).

  13. Biology and ecology of mycotoxigenic Aspergillus species as related to economic and health concerns.

    PubMed

    Wilson, David M; Mubatanhema, Wellington; Jurjevic, Zeljko

    2002-01-01

    The fungal genus Aspergillus was established in 1729, and includes species that are adapted to a wide range of environmental conditions. Many aspergilli produce mycotoxins in foods that may be toxic, mutagenic or carcinogenic in animals. Most of the Aspergillus species are soil fungi or saprophytes but some are capable of causing decay in storage, disease in plants or invasive disease in humans and animals. Major agricultural commodities affected before or after harvest by fungal growth and mycotoxins include corn, peanuts, cottonseed, rice, tree nuts, cereal grains, and fruits. Animal products (meat, milk and eggs) can become contaminated because of diet. Aspergillus flavus, A. parasiticus, A. ochraceus, A. niger, A. fumigatus and other aspergilli produce mycotoxins of concern. These include the aflatoxins and ochratoxins, as well as cyclopiazonic acid, patulin, sterigmatocystin, gliotoxin, citrinin and other potentially toxic metabolites.

  14. Direct visual detection of aflatoxin synthesis by minicolonies of Aspergillus species.

    PubMed Central

    Lemke, P A; Davis, N D; Creech, G W

    1989-01-01

    Single-spore colonies of Aspergillus flavus and Aspergillus parasiticus, grown for 4 to 5 days at 25 degrees C on a coconut extract agar containing sodium desoxycholate as a growth inhibitor, produced aflatoxin, readily detectable as blue fluorescent zones under long-wave (365 nm) UV light. Over 100 colonies per standard petri dish were scored for aflatoxin production by this procedure. Progeny from some strains remained consistently stable for toxin production after repeated subculture, whereas instability for toxin synthesis was revealed among progeny from other strains. Spore color markers were used to rule out cross-contamination in monitoring strains. A yellow-spored and nontoxigenic strain of A. flavus, reported previously to produce aflatoxin in response to cycloheximide treatment, proved to be toxin negative even after repeated exposure to cycloheximide. Extended series of progeny from another strain of A. flavus and from a strain of A. parasiticus were each compared by this plating procedure and by fluorometric analysis for aflatoxin when grown in a coconut extract broth. Both of these strains showed variation for toxin synthesis among their respective progeny, and specific progeny showed a good correlation for aflatoxin synthesis when examined by the two procedures. Images PMID:2504116

  15. Environmental contamination by Aspergillus spp. in laying hen farms and associated health risks for farm workers.

    PubMed

    Cafarchia, Claudia; Camarda, Antonio; Iatta, Roberta; Danesi, Patrizia; Favuzzi, Vincenza; Di Paola, Giancarlo; Pugliese, Nicola; Caroli, Anna; Montagna, Maria Teresa; Otranto, Domenico

    2014-03-01

    Data on the occurrence and epidemiology of Aspergillus spp. in laying hens farms are scant. With the aims of determining levels of airborne contamination in laying hen farms and evaluating the potential risk of infection for workers and animals, 57 air samples from 19 sheds (Group I), 69 from faeces (Group II), 19 from poultry feedstuffs (Group III) and 60 from three anatomical sites (i.e. nostrils, pharynx, ears) of 20 farm workers (Group IV) were cultured. The Aspergillus spp. prevalence in samples ranged from 31.6% (Group III) to 55.5% (Group IV), whereas the highest conidia concentration was retrieved in Group II (1.2 × 10(4) c.f.u. g(-1)) and in Group III (1.9 × 10(3) c.f.u. g(-1)). The mean concentration of airborne Aspergillus spp. conidia was 70 c.f.u. m(-3) with Aspergillus fumigatus (27.3%) being the most frequently detected species, followed by Aspergillus flavus (6.3%). These Aspergillus spp. were also isolated from human nostrils (40%) and ears (35%) (P<0.05) (Group IV). No clinical aspergillosis was diagnosed in hens. The results demonstrate a relationship between the environmental contamination in hen farms and presence of Aspergillus spp. on animals and humans. Even if the concentration of airborne Aspergillus spp. conidia (i.e. 70 c.f.u. m(-3)) herein detected does not trigger clinical disease in hens, it causes human colonization. Correct management of hen farms is necessary to control environmental contamination by Aspergillus spp., and could lead to a significant reduction of animal and human colonization.

  16. Using aCGH to study intraspecific genetic variability in two pathogenic molds, Aspergillus fumigatus and Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intraspecific molecular divergence is the basis of all sequence-based typing methods employed in many clinical laboratories to differentiate strains of pathogenic fungi. We have examined the feasibility of using array comparative genomic hybridization (aCGH) approaches to explore the extent of gene...

  17. Antifungal Activity and Aflatoxin Degradation of Bifidobacterium Bifidum and Lactobacillus Fermentum Against Toxigenic Aspergillus Parasiticus

    PubMed Central

    Ghazvini, Roshanak Daie; Kouhsari, Ebrahim; Zibafar, Ensieh; Hashemi, Seyed Jamal; Amini, Abolfazl; Niknejad, Farhad

    2016-01-01

    Food and feedstuff contamination with aflatoxins (AFTs) is a serious health problem for humans and animals, especially in developing countries. The present study evaluated antifungal activities of two lactic acid bacteria (LAB) against growth and aflatoxin production of toxigenic Aspergillus parasiticus. The mycelial growth inhibition rate of A. parasiticus PTCC 5286 was investigated in the presence of Bifidobacterium bifidum PTCC 1644 and Lactobacillus fermentum PTCC 1744 by the pour plate method. After seven days incubation in yeast extract sucrose broth at 30°C, the mycelial mass was weighed after drying. The inhibitory activity of LAB metabolites against aflatoxin production by A. parasiticus was evaluated using HPLC method. B. bifidum and L. fermentum significantly reduced aflatoxin production and growth rate of A. parasiticus in comparison with the controls (p≤0.05). LAB reduced total aflatoxins and B1, B2, G1 and G2 fractions by more than 99%. Moreover, LAB metabolites reduced the level of standard AFB1, B2, G1 and G2 from 88.8% to 99.8% (p≤0.05). Based on these findings, B. bifidum and L. fermentum are recommended as suitable biocontrol agents against the growth and aflatoxin production by aflatoxigenic Aspergillus species. PMID:28077976

  18. Molecular analysis of Aspergillus section Flavi isolated from Brazil nuts.

    PubMed

    Gonçalves, Juliana Soares; Ferracin, Lara Munique; Carneiro Vieira, Maria Lucia; Iamanaka, Beatriz Thie; Taniwaki, Marta Hiromi; Pelegrinelli Fungaro, Maria Helena

    2012-04-01

    Brazil nuts are an important export market in its main producing countries, including Brazil, Bolivia, and Peru. Approximately 30,000 tons of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs with subsequent production of aflatoxins. In our study, Aspergillus section Flavi were isolated from Brazil nuts (Bertholletia excelsa), and identified by morphological and molecular means. We obtained 241 isolates from nut samples, 41% positive for aflatoxin production. Eighty-one isolates were selected for molecular investigation. Pairwise genetic distances among isolates and phylogenetic relationships were assessed. The following Aspergillus species were identified: A. flavus, A. caelatus, A. nomius, A. tamarii, A. bombycis, and A. arachidicola. Additionally, molecular profiles indicated a high level of nucleotide variation within β-tubulin and calmodulin gene sequences associated with high genetic divergence from RAPD data. Among the 81 isolates analyzed by molecular means, three of them were phylogenetically distinct from all other isolates representing the six species of section Flavi. A putative novel species was identified based on molecular profiles.

  19. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1 †

    PubMed Central

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

    2014-01-01

    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

  20. Monitoring of aflatoxin G1, B1, G2, and B2 occurrence in some samples of walnut.

    PubMed

    Habibipour, Reza; Tamandegani, Parisa Rahimi; Farmany, Abbas

    2016-12-01

    This research was conducted to monitor the aflatoxigenic fungi and aflatoxin contamination of walnut in the Hamedan province. For this purpose, 40 samples were analyzed. Aspergillus, Alternaria, Rhizopus, Cladosporium, Fusarium, yeast, and some different bacteria were isolated from walnuts. Aspergillus is the most frequent genus. Aspergillus flavus was predominantly isolated. HPLC was used for evaluation of aflatoxin contamination of walnut samples. Aflatoxins G1 (AFG1), B1 (AFB1), G2 (AFG2), and B2 (AFB2) were produced by 20 isolates. AFG1 and AFB1 were being predominant at concentration ranges of 1.7-18.2 and 0-8.2 ngg(-1), respectively. Highest levels were found in one sample that was highly contaminated with Aspergillus flavus/Aspergillus parasiticus. Methyl beta cyclodextrin also was performed for detection of aflatoxigenic Aspergillus isolates. The results showed that only 31.6% (p < 0.05) of A. flavus and A. parasiticus isolates were able to produce aflatoxin. A significant difference was shown between shielded and unshielded walnut in aflatoxin contamination. The content of aflatoxin in most of the walnut samples did not reach to maximum tolerable limit for aflatoxin B1 in EU standard (p > 0.05). Thus, systematic and continues monitoring of walnuts is recommended.

  1. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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, when applied/used as an antifungal agent....

  2. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NRRL 21882 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....

  3. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NRRL 21882 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....

  4. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NRRL 21882 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....

  5. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NRRL 21882 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....

  6. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NRRL 21882 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....

  7. Hypersensitivity Pneumonitis in a Housewife Exposed to Aspergillus flavus in Poor Living Conditions: A Case Report

    PubMed Central

    Estibeiro, Anita Sandhya Mendonca; Mesquita, Anthony Menezes

    2016-01-01

    Hypersensitivity Pneumonitis (HP) or Extrinsic Allergic Alveolitis (EAA) is a disease resulting from immunologically induced inflammation in response to inhalation of a wide variety of airborne allergens. The condition develops mainly in non atopic individuals sensitized to organic dust due to repeated exposures. It is a relatively rare disease constituting upto 2% of interstitial lung diseases. Knowledge of classical High Resolution Computed Tomography (HRCT) of lung findings aid in early diagnosis. We report a case of subacute hypersensitivity pneumonitis in a housewife who despite being symptomatic remained undiagnosed for two years. She showed a good response to therapy, but soon relapsed. Visit to her home revealed that she lived in a damp house full of moldy walls. PMID:26894116

  8. Aflatoxin production and environmental oxidative stress in Aspergillus flavus: Implications forhost resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The contamination of maize kernel tissues with aflatoxin is of major concern in global food production, particularly in developing countries. Resistance to aflatoxin is negatively influenced by environmental stress, namely drought stress. Given that reactive oxygen species (ROS) are known to accumul...

  9. New Perspectives for the Application of Bioplastic Materials in the Biocontrol of Aspergillus flavus in Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins are secondary metabolities produced by certain filamentous fungi that can contaminate a large variety of agricultural commodities before and after harvest. Among different mycotoxins, aflatoxins and especially aflatoxin B1 are of particular concern because they are potent natural carcino...

  10. Functional analysis and structure determination of alkaline protease from Aspergillus flavus.

    PubMed

    Syed, Rabbani; Rani, Roja; Sabeena; Masoodi, Tariq Ahmad; Shafi, Gowher; Alharbi, Khalid

    2012-01-01

    Proteases are one of the highest value commercial enzymes as they have broad applications in food, pharmaceutical, detergent, and dairy industries and serve as vital tools in determination of structure of proteins and polypeptides. Multiple application of these enzymes stimulated interest to discover them with novel properties and considerable advancement of basic research into these enzymes. A broad understanding of the active site of the enzyme and of the mechanism of its inactivation is essential for delineating its structure-function relationship. Primary structure analysis of alkaline protease showed 42% of its content to be alpha helix making it stable for three dimensional structure modeling. Homology model of alkaline protease has been constructed using the X-ray structure (3F7O) as a template and swiss model as the workspace. The model was validated by ProSA, SAVES, PROCHECK, PROSAII and RMSD. The results showed the final refined model is reliable. It has 53% amino acid sequence identity with the template, 0.24 Å as RMSD and has -7.53 as Z-score, the Ramachandran plot analysis showed that conformations for 83.4 % of amino acid residues are within the most favored regions and only 0.4% in the disallowed regions.

  11. Blocking aflatoxins in corn by using non-toxigenic strains of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are over 500 previously reported mycotoxins. However, only a few have been identified as important for food safety, including aflatoxins, fumonisins, cyclopiazonic acid (CPA), trichothecenes, zearalenone, ochratoxins, and patulin. Mycotoxins contaminate plant materials, causing acute and ch...

  12. Effects of hydrogen peroxide on different toxigenic and atoxigenic isolates of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, t...

  13. Role of plant elicitor peptides and phytoalexins in enhancing maize resistance to Aspergillus flavus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize responds to pests and pathogens with complex defense responses. To facilitate effective breeding for pest and pathogen resistance, we’re elucidating cellular and molecular functions of regulatory and metabolic components of these maize defense responses. Our studies of regulatory components ha...

  14. Grain chemical composition as affected by genetic backgrounds and toxigenic Aspergillus flavus inoculation in corn hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins are secondary metabolites commonly found in corn and known to cause health issues to human and animals. The relationship between corn grain inoculated with mycotoxins and grain nutrients (protein, oil, fatty acids, sugars, and amino acids) corn hybrids, especially stacked-gene hybrids is...

  15. Toxigenic potential of Aspergillus species occurring on maize kernels from two agro-ecological zones in Kenya.

    PubMed

    Okoth, Sheila; Nyongesa, Beatrice; Ayugi, Vincent; Kang'ethe, Erastus; Korhonen, Hannu; Joutsjoki, Vesa

    2012-10-25

    Two agro-ecological zones in Kenya were selected to compare the distribution in maize of Aspergillus spp. and their toxigenicity. These were Nandi County, which is the main maize growing region in the country but where no human aflatoxicoses have been reported, and Makueni County where most of the aflatoxicosis cases have occurred. Two hundred and fifty-five households were sampled in Nandi and 258 in Makueni, and Aspergillus was isolated from maize. Aspergillus flavus and A. parasiticus isolates were tested for the presence of aflD and aflQ genes. Positive strains were induced to produce aflatoxins on yeast extract sucrose and quantified using liquid chromatography-tandem mass spectrometry (LCMSMS). Aspergillus flavus was the most common contaminant, and the incidence of occurrence in Nandi and Makueni was not significantly different (82.33% and 73.26%, respectively). Toxigenic strains were more prevalent than non-toxigenic strains. All the toxigenic strains from Makueni were of the S-type while those from Nandi belonged to the l-type. Quantitative differences in aflatoxin production in vitro between isolates and between strains were detected with S strains producing relatively larger amounts of total aflatoxins, B toxins and lower values for G toxins. This was in accord with the frequent aflatoxicosis outbreaks in Makueni. However some L strains produced considerable amounts of B toxins. Given the widespread distribution of toxigenic strains in both regions, the risk of aflatoxin poisoning is high when favorable conditions for toxin production occur.

  16. Aspergillus Collagen-Like Genes (acl): Identification, Sequence Polymorphism, and Assessment for PCR-Based Pathogen Detection

    PubMed Central

    Tuntevski, Kiril; Durney, Brandon C.; Snyder, Anna K.; LaSala, P. Rocco; Nayak, Ajay P.; Green, Brett J.; Beezhold, Donald H.; Rio, Rita V. M.; Holland, Lisa A.

    2013-01-01

    The genus Aspergillus is a burden to public health due to its ubiquitous presence in the environment, its production of allergens, and wide demographic susceptibility among cystic fibrosis, asthmatic, and immunosuppressed patients. Current methods of detection of Aspergillus colonization and infection rely on lengthy morphological characterization or nonstandardized serological assays that are restricted to identifying a fungal etiology. Collagen-like genes have been shown to exhibit species-specific conservation across the noncollagenous regions as well as strain-specific polymorphism in the collagen-like regions. Here we assess the conserved region of the Aspergillus collagen-like (acl) genes and explore the application of PCR amplicon size-based discrimination among the five most common etiologic species of the Aspergillus genus, including Aspergillus fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus. Genetic polymorphism and phylogenetic analysis of the aclF1 gene were additionally examined among the available strains. Furthermore, the applicability of the PCR-based assay to identification of these five species in cultures derived from sputum and bronchoalveolar fluid from 19 clinical samples was explored. Application of capillary electrophoresis on nanogels was additionally demonstrated to improve the discrimination between Aspergillus species. Overall, this study demonstrated that Aspergillus acl genes could be used as PCR targets to discriminate between clinically relevant Aspergillus species. Future studies aim to utilize the detection of Aspergillus acl genes in PCR and microfluidic applications to determine the sensitivity and specificity for the identification of Aspergillus colonization and invasive aspergillosis in immunocompromised subjects. PMID:24123732

  17. Biological control of AFB1-producing Aspergillus section Flavi strains isolated from brewer's grains, alternative feed intended for swine production in Argentina.

    PubMed

    Asurmendi, Paula; García, María J; Ruíz, Francisco; Dalcero, Ana; Pascual, Liliana; Barberis, Lucila

    2016-07-02

    The aim of the present study was to investigate the inhibitory activity of lactic acid bacteria (LAB) isolated from brewer's grains on Aspergillus section Flavi growth and aflatoxin B1 production. The Aspergillus strains tested were inhibited by all the LAB strains assayed. The isolates Lactobacillus brevis B20, P. pentosaceus B86, Lactococcus lactis subsp. lactis B87, L. brevis B131, and Lactobacillus sp. B144 completely suppressed the fungal growth and reduced aflatoxin B1 production. In conclusion, LAB isolated from brewer's grains show a high inhibitory activity on fungal growth and aflatoxin biosynthesis by Aspergillus flavus and Aspergillus parasiticus. Further studies must be conducted to evaluate the success of in vitro assays under food environment conditions and to elucidate the antifungal mechanism of these strains.

  18. LAMP-PCR detection of ochratoxigenic Aspergillus species collected from peanut kernel.

    PubMed

    Al-Sheikh, H M

    2015-01-30

    Over the last decade, ochratoxin A (OTA) has been widely described and is ubiquitous in several agricultural products. Ochratoxins represent the second-most important mycotoxin group after aflatoxins. A total of 34 samples were surveyed from 3 locations, including Mecca, Madina, and Riyadh, Saudi Arabia, during 2012. Fungal contamination frequency was determined for surface-sterilized peanut seeds, which were seeded onto malt extract agar media. Aspergillus niger (35%), Aspergillus ochraceus (30%), and Aspergillus carbonarius (25%) were the most frequently observed Aspergillius species, while Aspergillus flavus and Aspergillus phoenicis isolates were only infrequently recovered and in small numbers (10%). OTA production was evaluated on yeast extract sucrose medium, which revealed that 57% of the isolates were A. niger and 60% of A. carbonarius isolates were OTA producers; 100% belonged to A. ochraceus. Only one isolate, morphologically identified as A. carbonarius, and 3 A. niger isolates unstably produced OTA. A polymerase chain reaction (PCR)-based identification and detection assay was used to identify A. ochraceus isolates. Using the primer sets OCRA1/OCRA2, 400-base pair PCR fragments were produced only when genomic DNA from A. ochraceus isolates was used. Recently, the loop-mediated isothermal amplification assay using recombinase polymerase amplification chemistry was used for A. carbonarius and A. niger DNA identification. As a non-gel-based technique, the amplification product was directly visualized in the reaction tube after adding calcein for naked-eye examination.

  19. Aflatoxin contamination in soybeans: role of proteinase inhibitors, zinc availability, and seed coat integrity.

    PubMed Central

    Stössel, P

    1986-01-01

    Soybean trypsin inhibitors are thought to ward off pathogens. Studies with aflatoxigenic strains of Aspergillus flavus and A. parasiticus, frequent soybean contaminants, revealed that trypsin inhibitors do not affect the growth of these fungi and aflatoxin production. Further, the availability of zinc, an essential mineral for aflatoxin synthesis that was thought to explain increased aflatoxin accumulation in cooked compared with raw soybeans, was shown to decrease upon cooking. Seed coat integrity, ensuring limited access and a low moisture content, is responsible for the slow colonization of the seed by A. flavus. Images PMID:3089160

  20. Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India.

    PubMed

    Sangeetha Devi, Rajendran; Rajesh Kannan, Velu; Nivas, Duraisamy; Kannan, Kanthaiah; Chandru, Sekar; Robert Antony, Arokiaswamy

    2015-07-15

    High density polyethylene (HDPE) is the most commonly found non-degradable solid waste among the polyethylene. In this present study, HDPE degrading various fungal strains were isolated from the polyethylene waste dumped marine coastal area and screened under in vitro condition. Based on weight loss and FT-IR Spectrophotometric analysis, two fungal strains designated as VRKPT1 and VRKPT2 were found to be efficient in HDPE degradation. Through the sequence analysis of ITS region homology, the isolated fungi were identified as Aspergillus tubingensis VRKPT1 and Aspergillus flavus VRKPT2. The biofilm formation observed under epifluorescent microscope had shown the viability of fungal strains even after one month of incubation. The biodegradation of HDPE film nature was further investigated through SEM analysis. HDPE poses severe environmental threats and hence the ability of fungal isolates was proved to utilize virgin polyethylene as the carbon source without any pre-treatment and pro-oxidant additives.

  1. Identification of Aspergillus Species Using Internal Transcribed Spacer Regions 1 and 2

    PubMed Central

    Henry, Travis; Iwen, Peter C.; Hinrichs, Steven H.

    2000-01-01

    Aspergillus species are the most frequent cause of invasive mold infections in immunocompromised patients. Although over 180 species are found within the genus, 3 species, Aspergillus flavus, A. fumigatus, and A. terreus, account for most cases of invasive aspergillosis (IA), with A. nidulans, A. niger, and A. ustus being rare causes of IA. The ability to distinguish between the various clinically relevant Aspergillus species may have diagnostic value, as certain species are associated with higher mortality and increased virulence and vary in their resistance to antifungal therapy. A method to identify Aspergillus at the species level and differentiate it from other true pathogenic and opportunistic molds was developed using the 18S and 28S rRNA genes for primer binding sites. The contiguous internal transcribed spacer (ITS) region, ITS 1–5.8S–ITS 2, from referenced strains and clinical isolates of aspergilli and other fungi were amplified, sequenced, and compared with non-reference strain sequences in GenBank. ITS amplicons from Aspergillus species ranged in size from 565 to 613 bp. Comparison of reference strains and GenBank sequences demonstrated that both ITS 1 and ITS 2 regions were needed for accurate identification of Aspergillus at the species level. Intraspecies variation among clinical isolates and reference strains was minimal. Sixteen other pathogenic molds demonstrated less than 89% similarity with Aspergillus ITS 1 and 2 sequences. A blind study of 11 clinical isolates was performed, and each was correctly identified. Clinical application of this approach may allow for earlier diagnosis and selection of effective antifungal agents for patients with IA. PMID:10747135

  2. Development in Aspergillus

    PubMed Central

    Krijgsheld, P.; Bleichrodt, R.; van Veluw, G.J.; Wang, F.; Müller, W.H.; Dijksterhuis, J.; Wösten, H.A.B.

    2013-01-01

    The genus Aspergillus represents a diverse group of fungi that are among the most abundant fungi in the world. Germination of a spore can lead to a vegetative mycelium that colonizes a substrate. The hyphae within the mycelium are highly heterogeneous with respect to gene expression, growth, and secretion. Aspergilli can reproduce both asexually and sexually. To this end, conidiophores and ascocarps are produced that form conidia and ascospores, respectively. This review describes the molecular mechanisms underlying growth and development of Aspergillus. PMID:23450714

  3. Mycoflora and ochratoxin A producing strains of Aspergillus in Algerian wheat.

    PubMed

    Riba, A; Mokrane, S; Mathieu, F; Lebrihi, A; Sabaou, N

    2008-02-29

    Wheat is a basic staple food for very large segments of the population of Algeria. The aim of this study is to analyse ochratoxin A (OTA)-producing mould and OTA-contaminated wheat. To evaluate the mycoflora and the potential for OTA production by Aspergillus strains, a total of 85 samples of wheat destined for human consumption were collected from two regions in Algeria (Tizi Ouzou and Setif) during the following phases: preharvest, storage in silos, and after processing. The mean value counts of fungi ranged from 275 to 1277 CFU g(-1). The dominant genus was Aspergillus, predominantly A. flavus, A. niger and A. versicolor. The other isolated species were A. ochraceus, A. alliaceus, A. carbonarius, A. terreus, A. fumigatus, A. candidus and Aspergillus spp. The occurrence and the levels of the genus Penicillium, Fusarium, Alternaria and Mucor were substantially lower than those of Aspergillus. The storage in silos shows high levels of Aspergillus (66 to 84%), especially A. flavus, but A. niger and other fungi were isolated at relatively low percentages. Equal distribution of the fungal contamination into the bran, flour and semolina fractions was observed from Flour Mill and Semolina Mill. The genus Aspergillus remained present at high levels at several phases of the production process. In addition, the ability to produce OTA by 135 isolates belonging to eleven species of Aspergillus and 23 isolates of Penicillium spp. was analyzed using fluorescent detection-based HPLC. Thus, it was found that 51 isolates (32.3%) were ochratoxigenic. All isolated strains of A. ochraceus (12) and A. alliaceus (6) produced OTA at concentrations ranging from 0.23 to 11.50 microg g(-1). Most of the A. carbonarius strains (80%) were OTA producers (0.01 to 9.35 microg g(-1)), whereas A. terreus (50%), A. niger (28%), A. fumigatus (40%), A. versicolor (18%) and Penicillium spp. (21.7%) were low level producers (0.01 to 0.07 microg g(-1)). The concentration of OTA was determined in 30

  4. Application of essential oils in maize grain: impact on Aspergillus section Flavi growth parameters and aflatoxin accumulation.

    PubMed

    Bluma, Romina V; Etcheverry, Miriam G

    2008-04-01

    The antifungal activity of Pimpinella anisum L. (anise), Pëumus boldus Mol (boldus), Hedeoma multiflora Benth (mountain thyme), Syzygium aromaticum L. (clove), and Lippia turbinate var. integrifolia (griseb) (poleo) essential oils (EOs) against Aspergillus section Flavi was evaluated in sterile maize grain under different water activity (a(w)) condition (0.982, 0.955, and 0.90). The effect of EOs added to maize grains on growth rate, lag phase, and aflatoxin B(1) (AFB(1)) accumulation of Aspergillus section Flavi were evaluated at different water activity conditions. The five EOs analyzed have been shown to influence lag phase and growth rate. Their efficacy depended mainly on the essential oil concentrations and substrate water activity conditions. All EOs showed significant impact on AFB(1) accumulation. This effect was closely dependent on the water activity, concentration, and incubation periods. Important reduction of AFB(1) accumulation was observed in the majority of EO treatments at 11 days of incubation. Boldus, poleo, and mountain thyme EO completely inhibited AFB(1) at 2000 and 3000 microg g(-1). Inhibition of AFB(1) accumulation was also observed when aflatoxigenic isolates grew with different concentration of EOs during 35 days.

  5. Identification by Molecular Methods and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and Antifungal Susceptibility Profiles of Clinically Significant Rare Aspergillus Species in a Referral Chest Hospital in Delhi, India.

    PubMed

    Masih, Aradhana; Singh, Pradeep K; Kathuria, Shallu; Agarwal, Kshitij; Meis, Jacques F; Chowdhary, Anuradha

    2016-09-01

    Aspergillus species cause a wide spectrum of clinical infections. Although Aspergillus fumigatus and Aspergillus flavus remain the most commonly isolated species in aspergillosis, in the last decade, rare and cryptic Aspergillus species have emerged in diverse clinical settings. The present study analyzed the distribution and in vitro antifungal susceptibility profiles of rare Aspergillus species in clinical samples from patients with suspected aspergillosis in 8 medical centers in India. Further, a matrix-assisted laser desorption ionization-time of flight mass spectrometry in-house database was developed to identify these clinically relevant Aspergillus species. β-Tubulin and calmodulin gene sequencing identified 45 rare Aspergillus isolates to the species level, except for a solitary isolate. They included 23 less common Aspergillus species belonging to 12 sections, mainly in Circumdati, Nidulantes, Flavi, Terrei, Versicolores, Aspergillus, and Nigri Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identified only 8 (38%) of the 23 rare Aspergillus isolates to the species level. Following the creation of an in-house database with the remaining 14 species not available in the Bruker database, the MALDI-TOF MS identification rate increased to 95%. Overall, high MICs of ≥2 μg/ml were noted for amphotericin B in 29% of the rare Aspergillus species, followed by voriconazole in 20% and isavuconazole in 7%, whereas MICs of >0.5 μg/ml for posaconazole were observed in 15% of the isolates. Regarding the clinical diagnoses in 45 patients with positive rare Aspergillus species cultures, 19 (42%) were regarded to represent colonization. In the remaining 26 patients, rare Aspergillus species were the etiologic agent of invasive, chronic, and allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, keratitis, and mycetoma.

  6. Identification by Molecular Methods and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Antifungal Susceptibility Profiles of Clinically Significant Rare Aspergillus Species in a Referral Chest Hospital in Delhi, India

    PubMed Central

    Masih, Aradhana; Singh, Pradeep K.; Kathuria, Shallu; Agarwal, Kshitij

    2016-01-01

    Aspergillus species cause a wide spectrum of clinical infections. Although Aspergillus fumigatus and Aspergillus flavus remain the most commonly isolated species in aspergillosis, in the last decade, rare and cryptic Aspergillus species have emerged in diverse clinical settings. The present study analyzed the distribution and in vitro antifungal susceptibility profiles of rare Aspergillus species in clinical samples from patients with suspected aspergillosis in 8 medical centers in India. Further, a matrix-assisted laser desorption ionization–time of flight mass spectrometry in-house database was developed to identify these clinically relevant Aspergillus species. β-Tubulin and calmodulin gene sequencing identified 45 rare Aspergillus isolates to the species level, except for a solitary isolate. They included 23 less common Aspergillus species belonging to 12 sections, mainly in Circumdati, Nidulantes, Flavi, Terrei, Versicolores, Aspergillus, and Nigri. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identified only 8 (38%) of the 23 rare Aspergillus isolates to the species level. Following the creation of an in-house database with the remaining 14 species not available in the Bruker database, the MALDI-TOF MS identification rate increased to 95%. Overall, high MICs of ≥2 μg/ml were noted for amphotericin B in 29% of the rare Aspergillus species, followed by voriconazole in 20% and isavuconazole in 7%, whereas MICs of >0.5 μg/ml for posaconazole were observed in 15% of the isolates. Regarding the clinical diagnoses in 45 patients with positive rare Aspergillus species cultures, 19 (42%) were regarded to represent colonization. In the remaining 26 patients, rare Aspergillus species were the etiologic agent of invasive, chronic, and allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, keratitis, and mycetoma. PMID:27413188

  7. The potential of Origanum vulgare L. (Lamiaceae) essential oil in inhibiting the growth of some food-related Aspergillus species

    PubMed Central

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite

    2008-01-01

    Origanum vulgare L. (Lamiaceae) has been currently known for their interesting antimicrobial activity being regarded as alternative antimicrobial for use is food conservation systems. This study aimed to evaluate the effectiveness of O. vulgare essential oil in inhibiting the growth of some food-related Aspergillus species (A. flavus, A. parasiticus, A. terreus, A. ochraceus, A. fumigatus and A. niger). The essential oil revealed a strong anti-Aspergillus property providing an inhibition of all assayed mould strains. MIC values were between 80 and 20 μL/mL being found a MIC50 of 40 μL/mL. The essential oil at concentration of 80 and 40 μL/mL provided a fungicidal effect on A. flavus, A. fumigatus and A. niger noted by a total inhibition of the radial mycelial growth along 14 days of interaction. In addition, the essential oil was able to inhibit the mould spores germination when assayed at concentrations of 80 and 40 μL/mL. Our results showed the interesting anti-Aspergillus activity of O. vulgare essential oil supporting their possible use as anti-mould compound in food conservation. PMID:24031231

  8. Isolation of culturable mycobiota from agricultural soils and determination of tolerance to glyphosate of nontoxigenic Aspergillus section Flavi strains.

    PubMed

    Carranza, Cecilia S; Barberis, Carla L; Chiacchiera, Stella M; Dalcero, Ana María; Magnoli, Carina E

    2016-01-01

    Glyphosate-based herbicides are extensively used in Argentina's agricultural system to control undesirable weeds. This study was conducted to evaluate the culturable mycobiota [colony forming units (CFU) g(-1) and frequency of fungal genera or species] from an agricultural field exposed to pesticides. In addition, we evaluated the tolerance of A. oryzae and nontoxigenic A. flavus strains to high concentrations (100 to 500 mM - 17,000 to 84,500 ppm) of a glyphosate commercial formulation. The analysis of the mycobiota showed that the frequency of the main fungal genera varied according to the analyzed sampling period. Aspergillus spp. or Aspergillus section Flavi strains were isolated from 20 to 100% of the soil samples. Sterilia spp. were also observed throughout the sampling (50 to 100%). Aspergillus section Flavi tolerance assays showed that all of the tested strains were able to develop at the highest glyphosate concentration tested regardless of the water availability conditions. In general, significant reductions in growth rates were observed with increasing concentrations of the herbicide. However, a complete inhibition of fungal growth was not observed with the concentrations assayed. This study contributes to the knowledge of culturable mycobiota from agricultural soils exposed to pesticides and provides evidence on the effective growth ability of A. oryzae and nontoxigenic A. flavus strains exposed to high glyphosate concentrations in vitro.

  9. Effect of Carum copticum essential oil on growth and aflatoxin formation by Aspergillus strains.

    PubMed

    Kazemi, M

    2015-01-01

    The objectives of this study were to determine the antiaflatoxin B1 activity in vitro of the essential oil (EO) extracted from the seeds of Carum copticum and to evaluate its antifungal activity in vivo as a potential food preservative. The C. copticum EO exhibited noticeable inhibition on dry mycelium and synthesis of aflatoxin B1 (AFB1) by Aspergillus flavus, completely inhibiting AFB1 production at 4 μL/mL. C. copticum EOs showed the lowest percentages of decayed cherry tomatoes for all fungi compared with the control at 100 μL/mL with values of 5.01 ± 67% for A. flavus and 5.98 ± 54% for Aspergillus niger. The results indicated that the percentage of infected fruits is significantly (p < 0.01) reduced by the EO at 16°C for 30 days. In this case, the oil at 100 μL/mL concentration showed the highest inhibition of fungal infection with a value of 80.45% compared with the control. Thus, the EO of dill could be used to control food spoilage and as a potential source of food preservative.

  10. Flavone Biotransformation by Aspergillus niger and the Characterization of Two Newly Formed Metabolites

    PubMed Central

    Assawah, Suzan W.; El-Sharkawy, Saleh H.; Abdel-Salam, Amal

    2008-01-01

    Aspergillus niger isolated from Allium sativum was used at large scale fermentation (150 mg flavone/200 ml medium) to obtain suitable amounts of the products, efficient for identification. Then spectral analysis (UV, IR, 1H-NMR, 13C-NMR) and mass spectrometry were performed for the two products, which contributed to the identification process. The metabolite (1) was identified as 2'-hydroxydihydrochalcone, and the metabolite (2) was identified as 2'-hydroxyphenylmethylketone, which were more active than flavone itself. Antioxidant activities of the two isolated metabolites were tested compared with ascorbic acid. Antioxidant activity of metabolite (1) was recorded 64.58% which represented 79% of the antioxidant activity of ascorbic acid, and metabolite (2) was recorded 54.16% (67% of ascorbic acid activity). However, the antioxidant activity of flavone was recorded 37.50% which represented 46% of ascorbic acid activity. The transformed products of flavone have antimicrobial activity against Pseudomonas aeruginosa, Aspergillus flavus and Candida albicans, with MIC was recorded 250 µg/ml for metabolite (2) against all three organism and 500, 300, and 300 µg/ml for metabolite (1) against tested microorganisms (P. aeruginosa, Escherichia coli, Bacillus subtilis, and Klebsiella pneumonia, Fusarium moniliforme, A. flavus, Saccharomyces cerviceae, Kluveromyces lactis and C. albicans) at this order. PMID:23990746

  11. Chemical composition and antifungal activity of Hyptis Suaveolens (L.) Poit leaves essential oil against Aspergillus species

    PubMed Central

    Moreira, Ana Carolina Pessoa; de Oliveira Lima, Edeltrudes; Wanderley, Paulo Alves; Carmo, Egberto Santos; de Souza, Evandro Leite

    2010-01-01

    This study aimed to identify the constituents of the essential oil from Hyptis suaveolens (L.) leaves using a Gas Chromatograph - Mass Spectrometer and assess its inhibitory effect on some potentially pathogenic Aspergilli (A. flavus, A. parasiticus, A. ochraceus, A. fumigatus and A. niger). Eucaliptol (47.64 %) was the most abundant component in the oil, followed for gama-ellemene (8.15 %), beta-pynene (6.55 %), (+)-3-carene (5.16 %), trans-beta-cariophyllene (4.69 %) and germacrene (4.86 %). The essential oil revealed an interesting anti-Aspergillus property characterized by a Minimum Inhibitory Concentration and Minimum Fungicidal Concentration of 40 and 80 µL/mL, respectively. The oil at 80 and 40 µL/mL strongly inhibited the mycelial growth of A. fumigatus and A. parasiticus along 14 days. In addition, at 10 and 20 µL/mL the oil was able to cause morphological changes in A. flavus as decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure suggesting fungal wall degeneration. These findings showed the interesting anti-Aspergillus property of H. suaveolens leaves essential oil supporting its possible rational use as alternative source of new antifungal compounds to be applied in the aspergillosis treatment. PMID:24031459

  12. Multicenter Study of Isavuconazole MIC Distributions and Epidemiological Cutoff Values for Aspergillus spp. for the CLSI M38-A2 Broth Microdilution Method

    PubMed Central

    Chowdhary, A.; Gonzalez, G. M.; Lass-Flörl, C.; Martin-Mazuelos, E.; Meis, J.; Peláez, T.; Pfaller, M. A.; Turnidge, J.

    2013-01-01

    Epidemiological cutoff values (ECVs) were established for the new triazole isavuconazole and Aspergillus species wild-type (WT) MIC distributions (organisms in a species-drug combination with no detectable acquired resistance mechanisms) that were defined with 855 Aspergillus fumigatus, 444 A. flavus, 106 A. nidulans, 207 A. niger, 384 A. terreus, and 75 A. versicolor species complex isolates; 22 Aspergillus section Usti isolates were also included. CLSI broth microdilution MIC data gathered in Europe, India, Mexico, and the United States were aggregated to statistically define ECVs. ECVs were 1 μg/ml for the A. fumigatus species complex, 1 μg/ml for the A. flavus species complex, 0.25 μg/ml for the A. nidulans species complex, 4 μg/ml for the A. niger species complex, 1 μg/ml for the A. terreus species complex, and 1 μg/ml for the A. versicolor species complex; due to the small number of isolates, an ECV was not proposed for Aspergillus section Usti. These ECVs may aid in detecting non-WT isolates with reduced susceptibility to isavuconazole due to cyp51A (an A. fumigatus species complex resistance mechanism among the triazoles) or other mutations. PMID:23716059

  13. In vitro activities of amphotericin B and AmBisome against Aspergillus isolates recovered from Italian patients treated for haematological malignancies.

    PubMed

    Colozza, Camilla; Posteraro, Brunella; Santilli, Stefania; De Carolis, Elena; Sanguinetti, Maurizio; Girmenia, Corrado

    2012-05-01

    Although there is evidence that liposomal amphotericin B (AmBisome) is non-inferior to amphotericin B (AmB) in terms of in vivo efficacy, in vitro data regarding the activity of AmBisome against clinical isolates of Aspergillus are rare. In this study, the susceptibilities to AmB and AmBisome of 103 Aspergillus complex isolates (48 Aspergillus flavus, 33 Aspergillus fumigatus, 13 Aspergillus terreus and 9 Aspergillus niger) recovered from haematological patients with invasive infection were compared. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution (BMD) method according to the Clinical and Laboratory Standards Institute (CLSI), whilst AmB susceptibility was also determined by Etest. Using a susceptible/resistant MIC cut-off of 1mg/L, all A. fumigatus and A. niger complexes isolates were susceptible to both AmB and AmBisome. In contrast, 38.5% and 30.8% of the A. terreus complex isolates were resistant to AmB and AmBisome, respectively, with good agreement between BMD and Etest methods. With respect to A. flavus complex isolates, 43.7% and 16.7% were resistant by the BMD method to AmBisome and AmB, respectively. For isolates with discrepant results, AmB MICs obtained by Etest were higher than those obtained for AmB by the BMD method and they were closer to those obtained for AmBisome by BMD. Aspergillus flavus AmB MICs ranged from 0.5 mg/L to 2 mg/L by the BMD method and from 1 mg/L to >16 mg/L by the Etest method, and AmBisome MICs ranged from 0.06 mg/L to >16 mg/L by the BMD method. Etest appears to be superior to the CLSI BMD method using AmB in detecting AmB resistance of Aspergillus spp., although the CLSI BMD method might be a suitable procedure if AmBisome is used as the test drug.

  14. The effect of humidity after gamma-irradiation on aflatoxin B-1 production of A. Flavus in ground nutmeg and peanut

    NASA Astrophysics Data System (ADS)

    Hilmy, N.; Chosdu, R.; Matsuyama, A.

    1995-02-01

    The effect of humidity of 75 up to 97% after irradiation on radiosensitivity and aflatoxin B1 production of Aspergillus flavus isolated from Indonesian nutmeg were examined. Irradiation doses used were 0;0.5;1 and 3 kGy. Mould free ground nutmeg and peanut were used as the growth media, and about 10 8 of spores were used to contaminate each of the media. Aflatoxin productions were measured after having incubated 3 days up to 5 months under humidity of 91 and 97%. Prior to HPLC analysis, aflatoxin was cleaned-up using an immunoaffinity column. The results were: (1) A. flavus indicated no or almost no growth under RH of 85% or less. (2) Under 91-97% RH, growth of mycelium and toxin production were inhibited more or less by irradiation up to 1 kGy, although the effectiveness of irradiation varied with different RH and media during postirradiation incubation. (3) By 3 kGy or more, both mycelium growth and toxin production of the mould were found to be completely inhibited. (4) The production of aflatoxin in nutmeg began after having incubated for 25 and 45 days and in peanut for 3 and 6 days under 97 and 91% RH, respectively.

  15. Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production: a potential source of botanical food preservative

    PubMed Central

    Gemeda, Negero; Woldeamanuel, Yimtubezinash; Asrat, Daniel; Debella, Asfaw

    2014-01-01

    Objective To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. Method In vitro antifungal and antiaflatoxigenic activity of essential oils was carried out using poisoned food techniques, spore germination assay, agar dilution assay, and aflatoxin arresting assay on toxigenic strains of Aspergillus species. Results Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogenic isolates of Aspergillus species. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 µl/mL by essential oils of T. ammi. The oil also showed, complete inhibition of spore germination at a concentration of 2 µl/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting aflatoxin production from Aspergillus niger and Aspergillus flavus at 0.5 and 0.75 µl/mL, respectively. Cymbopogon martinii, Foeniculum vulgare and T. ammi oils as antifungal were found superior over synthetic preservative. Moreover, a concentration of 5 336.297 µl/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity and strengthening its traditional reputations. Conclusions In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by storage fungi. PMID:25183114

  16. Biomarkers of Aspergillus spores

    NASA Astrophysics Data System (ADS)

    Sulc, Miroslav; Peslova, Katerina; Zabka, Martin; Hajduch, Marian; Havlicek, Vladimir

    2009-02-01

    We applied both matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometric and 1D sodium dodecylsulfate polyacrylamide gel electrophoretic (1D-PAGE) approaches for direct analysis of intact fungal spores of twenty four Aspergillus species. In parallel, we optimized various protocols for protein extraction from Aspergillus spores using acidic conditions, step organic gradient and variable sonication treatment. The MALDI-TOF mass spectra obtained from optimally prepared samples provided a reproducible fingerprint demonstrating the capability of the MALDI-TOF approach to type and characterize different fungal strains within the Aspergillus genus. Mass spectra of intact fungal spores provided signals mostly below 20 kDa. The minimum material amount represented 0.3 [mu]g (10,000 spores). Proteins with higher molecular weight were detected by 1D-PAGEE Eleven proteins were identified from three selected strains in the range 5-25 kDa by the proteomic approach. Hemolysin and hydrophobin have the highest relevance in host-pathogen interactions.

  17. The Potential Inhibitory Effect of Cuminum Cyminum, Ziziphora Clinopodioides and Nigella Sativa Essential Oils on the Growth of Aspergillus Fumigatus and Aspergillus

    PubMed Central

    Khosravi, A.R.; Minooeianhaghighi, M.H.; Shokri, H.; Emami, S.A.; S.M., Alavi; Asili, J.

    2011-01-01

    The goals of this study were to evaluate the effectiveness of Cuminum cyminum, Ziziphora clinopodioides and Nigella sativa essential oils to inhibit the growth of Aspergillus fumigatus and A. flavus and to evoke ultrastructural changes. The fungi were cultured into RPMI 1640 media in the presence of oils at concentrations of 8, 6, 5, 4, 3, 2, 1.5, 1.25, 1, 0.75 and 0.5 mg/ml in broth microdilution and 2, 1.5, 1 and 0.5 mg/ml in broth macrodilution methods with shaking for 48 h at 28oC. Conidial and mycelial samples exposed to 0.25, 0.5, 1, 1.5 and 2 mg essential oils/ml for 5 days in 2% yeast extract granulated plus 15% Saccharose media were processed for transmission electron microscopy (TEM). Based on broth dilution methods, C. cyminum and to a lesser extent Z. clinopodioides oils exhibited the strongest activity against A. fumigatus and A. flavus with MIC90 ranging from 0.25 to 1.5 mg/ml, while the oil from N. sativa exhibited relatively moderate activity against two above fungi with MIC90 ranging from 1.5 to 2 mg/ml. The main changes observed by TEM were in the cell wall, plasma membrane and membranous organelles; in particular, in the nuclei and mitochondria. These modifications in fungal structure were associated with the interference of the essential oils with the enzymes responsible for cell wall synthesis, which disturbed normal growth. Moreover, the essential oils caused high vacuolation of the cytoplasm, detachment of fibrillar layer of cell wall, plasma membrane disruption and disorganization of the nuclear and mitochondrial structures. Aspergillus fumigatus and A. flavus growth inhibition induced by these oils were found to be well-correlated with subsequent morphological changes of the fungi exposed to different fungistatic concentrations of the oils. Our results show the anti-Aspergillus activities of C. cyminum, Z. clinopodioides and N. sativa essential oils, which strengthens the potential use of these substances as anti-mould in the future. PMID

  18. The potential inhibitory effect of cuminum cyminum, ziziphora clinopodioides and nigella sativa essential oils on the growth of Aspergillus fumigatus and Aspergillus.

    PubMed

    Khosravi, A R; Minooeianhaghighi, M H; Shokri, H; Emami, S A; S M, Alavi; Asili, J

    2011-01-01

    The goals of this study were to evaluate the effectiveness of Cuminum cyminum, Ziziphora clinopodioides and Nigella sativa essential oils to inhibit the growth of Aspergillus fumigatus and A. flavus and to evoke ultrastructural changes. The fungi were cultured into RPMI 1640 media in the presence of oils at concentrations of 8, 6, 5, 4, 3, 2, 1.5, 1.25, 1, 0.75 and 0.5 mg/ml in broth microdilution and 2, 1.5, 1 and 0.5 mg/ml in broth macrodilution methods with shaking for 48 h at 28(o)C. Conidial and mycelial samples exposed to 0.25, 0.5, 1, 1.5 and 2 mg essential oils/ml for 5 days in 2% yeast extract granulated plus 15% Saccharose media were processed for transmission electron microscopy (TEM). Based on broth dilution methods, C. cyminum and to a lesser extent Z. clinopodioides oils exhibited the strongest activity against A. fumigatus and A. flavus with MIC90 ranging from 0.25 to 1.5 mg/ml, while the oil from N. sativa exhibited relatively moderate activity against two above fungi with MIC90 ranging from 1.5 to 2 mg/ml. The main changes observed by TEM were in the cell wall, plasma membrane and membranous organelles; in particular, in the nuclei and mitochondria. These modifications in fungal structure were associated with the interference of the essential oils with the enzymes responsible for cell wall synthesis, which disturbed normal growth. Moreover, the essential oils caused high vacuolation of the cytoplasm, detachment of fibrillar layer of cell wall, plasma membrane disruption and disorganization of the nuclear and mitochondrial structures. Aspergillus fumigatus and A. flavus growth inhibition induced by these oils were found to be well-correlated with subsequent morphological changes of the fungi exposed to different fungistatic concentrations of the oils. Our results show the anti-Aspergillus activities of C. cyminum, Z. clinopodioides and N. sativa essential oils, which strengthens the potential use of these substances as anti-mould in the future.

  19. Aspergillus nidulans verA is required for production of the mycotoxin sterigmatocystin.

    PubMed Central

    Keller, N P; Kantz, N J; Adams, T H

    1994-01-01

    Aspergillus nidulans produces the carcinogenic mycotoxin sterigmatocystin (ST), the next-to-last precursor in the aflatoxin (AF) biosynthetic pathway found in the closely related fungi Aspergillus flavus and Aspergillus parasiticus. We identified and characterized an A. nidulans gene, verA, that is required for converting the AF precursor versicolorin A to ST. verA is closely related to several polyketide biosynthetic genes involved in polyketide production in Streptomyces spp. and exhibits extended sequence similarity to A. parasiticus ver-1, a gene proposed to encode an enzyme involved in converting versicolorin A to ST. By performing a sequence analysis of the region 3' to verA, we identified two additional open reading frames, designated ORF1 and ORF2. ORF2 is closely related to a number of cytochrome P-450 monooxygenases, while ORF1 shares identity with the gamma subunit of translation elongation factor 1. Given that several steps in the ST-AF pathway may require monooxygenase activity and that AF biosynthetic genes are clustered in A. flavus and A. parasiticus, we suggest that verA may be part of a cluster of genes required for ST biosynthesis. We disrupted the verA coding region by inserting the A. nidulans argB gene into the center of the coding region and transformed an A. nidulans argB2 mutant to arginine prototrophy. Seven transformants that produced DNA patterns indicative of a verA disruption event were grown under ST-inducing conditions, and all of the transformants produced versicolorin A but negligible amounts of ST (200-fold to almost 1,000-fold less than the wild type), confirming the hypothesis that verA encodes an enzyme necessary for converting versicolorin A to ST. Images PMID:8017929

  20. Determining the analytical specificity of PCR-based assays for the diagnosis of IA: What is Aspergillus?

    PubMed

    Morton, C Oliver; White, P Lewis; Barnes, Rosemary A; Klingspor, Lena; Cuenca-Estrella, Manuel; Lagrou, Katrien; Bretagne, Stéphane; Melchers, Willem; Mengoli, Carlo; Caliendo, Angela M; Cogliati, Massimo; Debets-Ossenkopp, Yvette; Gorton, Rebecca; Hagen, Ferry; Halliday, Catriona; Hamal, Petr; Harvey-Wood, Kathleen; Jaton, Katia; Johnson, Gemma; Kidd, Sarah; Lengerova, Martina; Lass-Florl, Cornelia; Linton, Chris; Millon, Laurence; Morrissey, C Orla; Paholcsek, Melinda; Talento, Alida Fe; Ruhnke, Markus; Willinger, Birgit; Donnelly, J Peter; Loeffler, Juergen

    2016-10-07

    A wide array of PCR tests has been developed to aid the diagnosis of invasive aspergillosis (IA), providing technical diversity but limiting standardisation and acceptance. Methodological recommendations for testing blood samples using PCR exist, based on achieving optimal assay sensitivity to help exclude IA. Conversely, when testing more invasive samples (BAL, biopsy, CSF) emphasis is placed on confirming disease, so analytical specificity is paramount. This multicenter study examined the analytical specificity of PCR methods for detecting IA by blind testing a panel of DNA extracted from a various fungal species to explore the range of Aspergillus species that could be detected, but also potential cross reactivity with other fungal species. Positivity rates were calculated and regression analysis was performed to determine any associations between technical specifications and performance. The accuracy of Aspergillus genus specific assays was 71.8%, significantly greater (P < .0001) than assays specific for individual Aspergillus species (47.2%). For genus specific assays the most often missed species were A. lentulus (25.0%), A. versicolor (24.1%), A. terreus (16.1%), A. flavus (15.2%), A. niger (13.4%), and A. fumigatus (6.2%). There was a significant positive association between accuracy and using an Aspergillus genus PCR assay targeting the rRNA genes (P = .0011). Conversely, there was a significant association between rRNA PCR targets and false positivity (P = .0032). To conclude current Aspergillus PCR assays are better suited for detecting A. fumigatus, with inferior detection of most other Aspergillus species. The use of an Aspergillus genus specific PCR assay targeting the rRNA genes is preferential.

  1. Aspergillus arthritis: analysis of clinical manifestations, diagnosis, and treatment of 31 reported cases.

    PubMed

    Gamaletsou, Maria N; Rammaert, Blandine; Bueno, Marimelle A; Sipsas, Nikolaos V; Moriyama, Brad; Kontoyiannis, Dimitrios P; Roilides, Emmanuel; Zeller, Valerie; Taj-Aldeen, Saad J; Henry, Michael; Petraitis, Vidmantas; Denning, David W; Lortholary, Olivier; Walsh, Thomas J

    2016-09-08

    Aspergillus arthritis is a debilitating form of invasive aspergillosis. Little is known about its epidemiology, clinical manifestations, laboratory features, treatment, and prognosis. Cases of Aspergillus arthritis were reviewed in the English literature from 1967 through 2015 for variables of arthritis with Aspergillus spp. recovered from joint and/or adjacent bone, underlying conditions, symptoms, signs, inflammatory biomarkers, diagnostic imaging, management, and outcome. Among 31 evaluable cases, 87% were males and 13% pediatric. Median age was 50 y (range 1-83 y). Seventeen (55%) patients were immunosuppressed with such conditions as hematological malignancies (26%), corticosteroids (39%), and/or transplantation (26%). Approximately one-half (52%) of patients had hematogenous seeding of the joint, and more than 80% had de novo infection with no prior antifungal therapy. Oligoarticular infection (2-3 joints) occurred in 45% and contiguous osteomyelitis was present in 61%. Clinical manifestations included pain (87%), edema (26%), and limited function (23%), with knees (35%), intervertebral discs (26%), and hips (16%) being most commonly infected. Aspergillus fumigatus constituted 77% of cases followed by Aspergillus flavus in 13%, Aspergillus niger in 3%, and not specified in 7%. Median ESR was 90 mm/hr and median CRP was 3.6 mg/dl. Median synovial fluid WBC was 17,200/μL (7,300-128,000) with 72% PMNs (range 61-92). Osteolysis occurred in 35%, and soft-tissue extension 47%. Nineteen patients (61%) were managed with combined medical and surgical therapy, 10 (32%) with medical therapy only, and 2 (6%) surgery only. Amphotericin B and itraconazole were the most frequently used agents with median duration of therapy of 219 days (range 30-545). Surgical interventions included debridement in 61%, drainage 19%, and amputation 6%. Complete or partial response was achieved in 71% and relapse occurred in 16%. Medical therapy was reinstituted with successful outcome in

  2. Previously unknown species of Aspergillus.

    PubMed

    Gautier, M; Normand, A-C; Ranque, S

    2016-08-01

    The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based identification of Aspergillus remains limited to the section or species-complex level. The current literature highlights two main features concerning these 'cryptic' Aspergillus species. First, the prevalence of such species in clinical samples is relatively high compared with emergent filamentous fungal taxa such as Mucorales, Scedosporium or Fusarium. Second, it is clearly important to identify these species in the clinical laboratory because of the high frequency of antifungal drug-resistant isolates of such Aspergillus species. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been shown to enable the identification of filamentous fungi with an accuracy similar to that of DNA sequence-based methods. As MALDI-TOF MS is well suited to the routine clinical laboratory workflow, it facilitates the identification of these 'cryptic' Aspergillus species at the routine mycology bench. The rapid establishment of enhanced filamentous fungi identification facilities will lead to a better understanding of the epidemiology and clinical importance of these emerging Aspergillus species. Based on routine MALDI-TOF MS-based identification results, we provide original insights into the key interpretation issues of a positive Aspergillus culture from a clinical sample. Which ubiquitous species that are frequently isolated from air samples are rarely involved in human invasive disease? Can both the species and the type of biological sample indicate Aspergillus carriage, colonization or infection in a patient? Highly accurate routine filamentous fungi identification is central to enhance the understanding of these previously unknown Aspergillus species, with a vital impact on further improved patient care.

  3. Disinfection efficacy of chlorine and peracetic acid alone or in combination against Aspergillus spp. and Candida albicans in drinking water.

    PubMed

    Sisti, Maurizio; Brandi, Giorgio; De Santi, Mauro; Rinaldi, Laura; Schiavano, Giuditta F

    2012-03-01

    The aim of the present study was to evaluate the fungicidal activity of chlorine and peracetic acid in drinking water against various pathogenic Aspergillus spp. and Candida albicans strains. A. nidulans exhibited the greatest resistance, requiring 10 ppm of chlorine for 30 min contact time for a complete inactivation. Under the same experimental conditions, peracetic acid was even less fungicidal. In this case, A. niger proved to be the most resistant species (50 ppm for 60 min for complete inactivation). All Aspergillus spp. were insensitive to 10 ppm even with extended exposure (>5 h). The combination of chlorine and peracetic acid against Aspergillus spp. did not show synergistic effects except in the case of A. flavus. Complete growth inhibition of C. albicans was observed after about 3 h contact time with 0.2 ppm. C. albicans was less sensitive to peracetic acid. Hence the concentrations of chlorine that are usually present in drinking water distribution systems are ineffective against several Aspergillus spp. and peracetic acid cannot be considered an alternative to chlorine for disinfecting drinking water. The combination of the two biocides is not very effective in eliminating filamentous fungi at the concentrations permitted for drinking water disinfection.

  4. Clinical implications of globally emerging azole resistance in Aspergillus fumigatus.

    PubMed

    Meis, Jacques F; Chowdhary, Anuradha; Rhodes, Johanna L; Fisher, Matthew C; Verweij, Paul E

    2016-12-05

    Aspergillus fungi are the cause of an array of diseases affecting humans, animals and plants. The triazole antifungal agents itraconazole, voriconazole, isavuconazole and posaconazole are treatment options against diseases caused by Aspergillus However, resistance to azoles has recently emerged as a new therapeutic challenge in six continents. Although de novo azole resistance occurs occasionally in patients during azole therapy, the main burden is the aquisition of resistance through the environment. In this setting, the evolution of resistance is attributed to the widespread use of azole-based fungicides. Although ubiquitously distributed, A. fumigatus is not a phytopathogen. However, agricultural fungicides deployed against plant pathogenic moulds such as Fusarium, Mycospaerella and A. flavus also show activity against A. fumigatus in the environment and exposure of non-target fungi is inevitable. Further, similarity in molecule structure between azole fungicides and antifungal drugs results in cross-resistance of A. fumigatus to medical azoles. Clinical studies have shown that two-thirds of patients with azole-resistant infections had no previous history of azole therapy and high mortality rates between 50% and 100% are reported in azole-resistant invasive aspergillosis. The resistance phenotype is associated with key mutations in the cyp51A gene, including TR34/L98H, TR53 and TR46/Y121F/T289A resistance mechanisms. Early detection of resistance is of paramount importance and if demonstrated, either with susceptibility testing or through molecular analysis, azole monotherapy should be avoided. Liposomal amphotericin B or a combination of voriconazole and an echinocandin are recomended for azole-resistant aspergillosis.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

  5. Aspergillus fumigatus in Poultry

    PubMed Central

    Arné, Pascal; Thierry, Simon; Wang, Dongying; Deville, Manjula; Le Loc'h, Guillaume; Desoutter, Anaïs; Féménia, Françoise; Nieguitsila, Adélaïde; Huang, Weiyi; Chermette, René; Guillot, Jacques

    2011-01-01

    Aspergillus fumigatus remains a major respiratory pathogen in birds. In poultry, infection by A. fumigatus may induce significant economic losses particularly in turkey production. A. fumigatus develops and sporulates easily in poor quality bedding or contaminated feedstuffs in indoor farm environments. Inadequate ventilation and dusty conditions increase the risk of bird exposure to aerosolized spores. Acute cases are seen in young animals following inhalation of spores, causing high morbidity and mortality. The chronic form affects older birds and looks more sporadic. The respiratory tract is the primary site of A. fumigatus development leading to severe respiratory distress and associated granulomatous airsacculitis and pneumonia. Treatments for infected poultry are nonexistent; therefore, prevention is the only way to protect poultry. Development of avian models of aspergillosis may improve our understanding of its pathogenesis, which remains poorly understood. PMID:21826144

  6. Aspergillus antigen skin test (image)

    MedlinePlus

    ... After 48 to 72 hours the site of injection is evaluated by a physician. If a positive reaction occurs (the test site is inflamed), the person has been exposed to the aspergillus mold and is at risk for developing aspergillosis.

  7. Modulation of antimicrobial metabolites production by the fungus Aspergillus parasiticus

    PubMed Central

    Bracarense, Adriana A.P.; Takahashi, Jacqueline A.

    2014-01-01

    Biosynthesis of active secondary metabolites by fungi occurs as a specific response to the different growing environments. Changes in this environment alter the chemical and biological profiles leading to metabolites diversification and consequently to novel pharmacological applications. In this work, it was studied the influence of three parameters (fermentation length, medium composition and aeration) in the biosyntheses of antimicrobial metabolites by the fungus Aspergillus parasiticus in 10 distinct fermentation periods. Metabolism modulation in two culturing media, CYA and YES was evaluated by a 22 full factorial planning (ANOVA) and on a 23 factorial planning, role of aeration, medium composition and carbohydrate concentration were also evaluated. In overall, 120 different extracts were prepared, their HPLC profiles were obtained and the antimicrobial activity against A. flavus, C. albicans, E. coli and S. aureus of all extracts was evaluated by microdilution bioassay. Yield of kojic acid, a fine chemical produced by the fungus A. parasiticus was determined in all extracts. Statistical analyses pointed thirteen conditions able to modulate the production of bioactive metabolites by A. parasiticus. Effect of carbon source in metabolites diversification was significant as shown by the changes in the HPLC profiles of the extracts. Most of the extracts presented inhibition rates higher than that of kojic acid as for the extract obtained after 6 days of fermentation in YES medium under stirring. Kojic acid was not the only metabolite responsible for the activity since some highly active extracts showed to possess low amounts of this compound, as determined by HPLC. PMID:24948950

  8. Larval morphology of Metaphycus flavus and its role in host attachment and larval cannibalism.

    PubMed

    Tena, A; Kapranas, A; Walker, G P; Garcia-Marí, F; Luck, R F

    2011-06-01

    Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50-70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.

  9. Epidemiological and Genomic Landscape of Azole Resistance Mechanisms in Aspergillus Fungi

    PubMed Central

    Hagiwara, Daisuke; Watanabe, Akira; Kamei, Katsuhiko; Goldman, Gustavo H.

    2016-01-01

    Invasive aspergillosis is a life-threatening mycosis caused by the pathogenic fungus Aspergillus. The predominant causal species is Aspergillus fumigatus, and azole drugs are the treatment of choice. Azole drugs approved for clinical use include itraconazole, voriconazole, posaconazole, and the recently added isavuconazole. However, epidemiological research has indicated that the prevalence of azole-resistant A. fumigatus isolates has increased significantly over the last decade. What is worse is that azole-resistant strains are likely to have emerged not only in response to long-term drug treatment but also because of exposure to azole fungicides in the environment. Resistance mechanisms include amino acid substitutions in the target Cyp51A protein, tandem repeat sequence insertions at the cyp51A promoter, and overexpression of the ABC transporter Cdr1B. Environmental azole-resistant strains harboring the association of a tandem repeat sequence and punctual mutation of the Cyp51A gene (TR34/L98H and TR46/Y121F/T289A) have become widely disseminated across the world within a short time period. The epidemiological data also suggests that the number of Aspergillus spp. other than A. fumigatus isolated has risen. Some non-fumigatus species intrinsically show low susceptibility to azole drugs, imposing the need for accurate identification, and drug susceptibility testing in most clinical cases. Currently, our knowledge of azole resistance mechanisms in non-fumigatus Aspergillus species such as A. flavus, A. niger, A. tubingensis, A. terreus, A. fischeri, A. lentulus, A. udagawae, and A. calidoustus is limited. In this review, we present recent advances in our understanding of azole resistance mechanisms particularly in A. fumigatus. We then provide an overview of the genome sequences of non-fumigatus species, focusing on the proteins related to azole resistance mechanisms. PMID:27708619

  10. Efficacy of Angelica archangelica essential oil, phenyl ethyl alcohol and α- terpineol against isolated molds from walnut and their antiaflatoxigenic and antioxidant activity.

    PubMed

    Prakash, Bhanu; Singh, Priyanka; Goni, Reema; Raina, Ajay Kumar Pandit; Dubey, N K

    2015-04-01

    Mold association, aflatoxin B1 contamination as well as oxidative deterioration of agri-food items during storage and processing are some global task for food industries. In view of the adverse effects of some synthetic preservatives on treated food items and subsequently on consumers health, recently plant based chemicals are encouraged by food industries as better alternatives of synthetics. The present study recommends the combination (1:1:1) of Angelica archangelica essential oil: Phenyl ethyl alcohol (PEA): α- terpineol as botanical preservative against molds, aflatoxin contamination and oxidative deterioration of walnut samples. Eight mold species were procured from stored walnut samples, including some aflatoxigenic Aspergillus flavus strains. The combination inhibited growth of aflatoxigenic strain Aspergillus flavus NKDW-7 and aflatoxin B1 production at 2.25 and 2.0 μL mL(-1) respectively. The IC50 value of the combination was recorded as 3.89 μL mL(-1), showing strong antioxidant potential. The antifungal action of the combination showed > 90 % decrease in ergosterol content in plasma membrane of A. flavus at 2.0 μL mL(-1). The LD50 of the combination, through oral administration on mice, was 9562.9 μL kg(-1) body weight, indication favourable safety profile as a plant based preservative. The combination may be recommended as safe preservative against molds, aflatoxin contamination and oxidative deterioration of walnut samples.

  11. Distribution and toxigenicity of Aspergillus species isolated from maize kernels from three agro-ecological zones in Nigeria.

    PubMed

    Atehnkeng, Joseph; Ojiambo, Peter S; Donner, Matthias; Ikotun, T; Sikora, Richard A; Cotty, Peter J; Bandyopadhyay, Ranajit

    2008-02-29

    Maize samples were collected during a survey in three agro-ecological zones in Nigeria to determine the distribution and aflatoxin-producing potential of members of Aspergillus section Flavi. The three agro-ecological zones were, Derived Savannah (DS) and Southern Guinea Savannah (SGS) in the humid south and North Guinea Savannah (NGS) in the drier north. Across agro-ecological zones, Aspergillus was the most predominant fungal genera identified followed by Fusarium with mean incidences of 70 and 24%, respectively. Among Aspergillus, A. flavus was the most predominant and L-strains constituted >90% of the species identified, while the frequency of the unnamed taxon S(BG) was <3%. The incidence of atoxigenic strains of A. flavus was higher in all the districts surveyed except in the Ogbomosho and Mokwa districts in DS and SGS zones, respectively, where frequency of toxigenic strains were significantly (P<0.05) higher than that of atoxigenic strains. The highest and lowest incidence of aflatoxin positive samples was recorded in the SGS (72%) and NGS (20%), respectively. Aflatoxin contamination in grain also followed a similar trend and the highest mean levels of B-aflatoxins were detected in maize samples obtained from Bida (612 ng g(-1)) and Mokwa (169 ng g(-1)) districts, respectively, in the SGS. Similarly, the highest concentrations of G-aflatoxins were detected in samples from Akwanga district in the SGS with a mean of 193 and 60 ng g(-1), respectively. When agro-ecological zones were compared, B-aflatoxins were significantly (P<0.05) higher in SGS than in NGS, and intermediate in maize samples from the DS agro-ecological zone.

  12. Aspergillus fumigatus and Aspergillosis

    PubMed Central

    Latgé, Jean-Paul

    1999-01-01

    Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy. PMID:10194462

  13. Tracheobronchial Manifestations of Aspergillus Infections

    PubMed Central

    Krenke, Rafal; Grabczak, Elzbieta M.

    2011-01-01

    Human lungs are constantly exposed to a large number of Aspergillus spores which are present in ambient air. These spores are usually harmless to immunocompetent subjects but can produce a symptomatic disease in patients with impaired antifungal defense. In a small percentage of patients, the trachea and bronchi may be the main or even the sole site of Aspergillus infection. The clinical entities that may develop in tracheobronchial location include saprophytic, allergic and invasive diseases. Although this review is focused on invasive Aspergillus tracheobronchial infections, some aspects of allergic and saprophytic tracheobronchial diseases are also discussed in order to present the whole spectrum of tracheobronchial aspergillosis. To be consistent with clinical practice, an approach basing on specific conditions predisposing to invasive Aspergillus tracheobronchial infections is used to present the differences in the clinical course and prognosis of these infections. Thus, invasive or potentially invasive Aspergillus airway diseases are discussed separately in three groups of patients: (1) lung transplant recipients, (2) highly immunocompromised patients with hematologic malignancies and/or patients undergoing hematopoietic stem cell transplantation, and (3) the remaining, less severely immunocompromised patients or even immunocompetent subjects. PMID:22194666

  14. Transformation of Aspergillus parasiticus with a homologous gene (pyrG) involved in pyrimidine biosynthesis

    SciTech Connect

    Skory, C.D.; Horng, J.S.; Pestka, J.J.; Linz, J.E. )

    1990-11-01

    The lack of efficient transformation methods for aflatoxigenic Aspergillus parasiticus has been a major constraint for the study of aflatoxin biosynthesis at the genetic level. A transformation system with efficiencies of 30 to 50 stable transformants per {mu}g of DNA was developed for A. parasiticus by using homologous pyrG gene. The pyrG gene from A. parasiticus was isolated by in situ plaque hybridization of a lambda genomic DNA library. Uridine auxotrophs of A. parasiticus ATCC 36537, a mutant blocked in aflatoxin biosynthesis, were isolated by selection on 5-fluoroorotic acid following nitrosoguanidine mutagenesis. Isolates with mutations in the pyrG gene resulting in elimination of orotidine monophosphate (OMP) decarboxylase activity were detected by assaying cell extracts for their ability to convert ({sup 14}C)OMP to ({sup 14}C)UMP. Transformation of A. parasiticus pyrG protoplasts with the homologous pyrG gene restored the fungal cells to prototrophy. Enzymatic analysis of cell extracts of transformant clones demonstrated that these extracts had the ability to convert ({sup 14}C)OMP to ({sup 14}C)UMP. Southern analysis of DNA purified from transformant clones indicated that both pUC19 vector sequences and pyrG sequences were integrated into the genome. The development of this pyrG transformation system should allow cloning of the aflatoxin-biosynthetic genes, which will be useful in studying the regulation of aflatoxin biosynthesis and may ultimately provide a means for controlling aflatoxin production in the field.

  15. 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

    ... practice on cotton in Arizona, California, and Texas without any reports of adverse dermal irritation or... strains, which are already present in the environment. Pistachio is grown in an arid environment, which... various levels of government or between ] the Federal Government and Indian tribes. Thus, EPA...

  16. Improved Enzyme Catalytic Characteristics upon Glutaraldehyde Cross-Linking of Alginate Entrapped Xylanase Isolated from Aspergillus flavus MTCC 9390

    PubMed Central

    Bhushan, Bharat; Pal, Ajay; Jain, Veena

    2015-01-01

    Purified fungal xylanase was entrapped in alginate beads. Its further cross-linking using glutaraldehyde resulted in large enzyme aggregates which may function as both a catalyst and a support material for numerous substrate molecules. Enzyme cross-linking presented a negative impact on enzyme leaching during repeated washings and recovery of enzyme activity was substantial after twelve cycles of usage. The entrapment followed by cross-linking doubled the total bound activity and also greatly improved the enzyme stability at extreme chemical environment. The wide pH stability, better thermo- and storage stability, lowered Km value, and protection from some metal ions are salient achievements of present immobilization. The study shows the efficacy, durability, and sustainability of immobilized catalytic system which could be efficiently used for various juice processing operations. PMID:26347814

  17. Inhibitory effect of the essential oil of Curcuma longa L. and curcumin on aflatoxin production by Aspergillus flavus Link.

    PubMed

    Ferreira, Flavio Dias; Kemmelmeier, Carlos; Arrotéia, Carla Cristina; da Costa, Christiane Luciana; Mallmann, Carlos Augusto; Janeiro, Vanderly; Ferreira, Francine Maery Dias; Mossini, Simone Aparecida Galerani; Silva, Expedito Leite; Machinski, Miguel

    2013-01-15

    Aflatoxins are highly toxic, mutagenic, teratogenic and carcinogenic mycotoxins. Consumption of aflatoxin-contaminated food and commodities poses serious hazards to the health of humans and animals. Turmeric, Curcuma longa L., is a native plant of Southeast Asia and has antimicrobial, antioxidant and antifungal properties. This paper reports the antiaflatoxigenic activities of the essential oil of C. longa and curcumin. The medium tests were prepared with the oil of C. longa, and the curcumin standard at concentrations varied from 0.01% to 5.0%. All doses of the essential oil of the plant and the curcumin standard interfered with mycotoxin production. Both the essential oil and curcumin significantly inhibited the production of aflatoxins; the 0.5% level had a greater than 96% inhibitory effect. The levels of aflatoxin B(1) (AFB(1)) production were 1.0 and 42.7 μg/mL, respectively, for the samples treated with the essential oil of C. longa L. and curcumin at a concentration of 0.5%.

  18. Larval preference and performance of Amyelois transitella (Navel orangeworm, Lepidoptera: Pyralidae) in relation to the fungus Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The navel orangeworm, Amyelois transitella (Walker), is a polyphagous pest of California nut crops and is responsible for extensive losses in the United States. It directly damages crops by feeding and contaminating nuts with frass and webbing and vectors saprophytic fungi that infect crops. The nav...

  19. Potential roles of secondary metabolite production in environmental oxidative stress responses revealed in the Aspergillus flavus transcriptome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The contamination of agricultural crops with aflatoxins is exacerbated in the dry and hot season worldwide, and poses a serious food security concern, particularly in developing countries. Drought stress results in the accumulation of reactive oxygen species (ROS) in the tissues of plants. Previousl...

  20. Mycological evaluation of chemically-treated unshelled peanuts.

    PubMed

    Ranzani, M R; Fonseca, H

    1995-01-01

    In the present work, the effect of propionic acid (ammonium salt) at 3000 mg/kg of unshelled peanuts (PA1) and at 5000 mg/kg (PA2), grapefruit seed extract at 5000 mg/kg (GF1) and 10,000 mg/kg (GF2), sodium orthophenylphenate at 2500 mg/kg (SOP1) and at 5000 mg/kg (SOP2) and thiabendazole at 1000 mg/kg (TBZ1) and at 5000 mg/kg (TBZ2) was studied for controlling total and potentially aflatoxigenic fungi in unshelled peanuts (UP). Samples of sound mature UP were moistened by adding water and kept refrigerated till they reached ca 16% moisture. The samples were then sprayed with the chemical solutions and incubated at 30 +/- 2 degrees C for 28 days. Control samples were sprayed with water. An evaluation of total and aflatoxigenic fungi was made, in pods of UP and in kernels obtained aseptically, before and at 7, 14, 21 and 28 days of incubation, by serial dilution in culture media Dichloran Rose Bengal Chloramphenicol (total fungi count) and in Aspergillus flavus parasiticus Agar (potentially aflatoxigenic count). In relation to the period and conditions of this experiment the overall best treatment was PA2, when the lowest average value of total and aflatoxigenic fungi were obtained in UP and were maintained in its kernels. Although SOP2 treatment could control fungal contamination in pods, it was not effective in controlling contamination through the kernels. The other treatments were ineffective.

  1. Obstructive cholelithiasis and cholecystitis in a kinkajou (Potos flavus).

    PubMed

    Potier, Romain; Reineau, Olivier

    2015-03-01

    A 14.5-yr-old female kinkajou (Potos flavus) was diagnosed with cholelithiasis after an episode of vomiting; diagnostics included biochemical analysis and abdominal ultrasound exam. Despite antimicrobial treatment, cholelithiasis led to cholecystitis. A cholecystotomy was performed to remove choleliths and inspissated bile. Morphological and spectroscopic properties of the choleliths were similar to those of gallstones from the brown pigment family and Streptococcus sp. and Escherichia coli were isolated from the bile. Biliary tract infection is directly related to pathogenesis of brown pigment gallstones. Serial ultrasound exams revealed that cholecystitis developed secondary to the presence of gallstones in the biliary tree. Despite full recovery postsurgery, the patient died 15 mo later from gallbladder necrosis. Based on the progression of this case, a cholecystectomy would be preferred over a cholecystotomy in similar cases, and the efficacy of long-acting antibiotics may not be adequate in nontarget species. Gallstones and biliary tract infection are rarely described in small domestic carnivores, and this is the first reported case in a kinkajou.

  2. Sexual recombination in Aspergillus tubingensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus tubingensis from section Nigri (Black Aspergilli) is closely related to A. niger and is used extensively in the industrial production of enzymes and organic acids. We recently discovered sexual reproduction in A. tubingensis and in this study, demonstrate that the progeny are products o...

  3. Effect of γ-radiation on the production of aflatoxin B1 by Aspergillus parasiticus in raisins (Vitis vinifera L.)

    NASA Astrophysics Data System (ADS)

    Kanapitsas, Alexandros; Batrinou, Anthimia; Aravantinos, Athanasios; Markaki, Panagiota

    2015-01-01

    Aflatoxin B1 (AFB1) mostly produced by Aspergillus flavus and Aspergillus parasiticus, is an extremely toxic and carcinogenic metabolite. The effect of gamma irradiation at dose of 10 kGy on the production of aflatoxin B1 (AFB1) inoculated by Aspergillus parasiticus in raisins (Vitis vinifera L.) and on AFB1 in contaminated samples, was investigated. Values of the amount of aflatoxin B1 produced on the 12th day of incubation, after irradiation, showed that gamma radiation exposure at 10 kGy decreased AFB1 production at 65% compared with the non-irradiated sample, on the same day. The application of 10 kGy gamma radiation directly on 100 ng of AFB1 which were spiked in raisins resulted in ~29% reduction of AFB1. According to the risk assessment analysis the Provisional Maximum Tolerable Daily Intake (PMTDI) of 1.0 ng AFB1 kg-1bw, indicates that consumers are less exposed to AFB1 from the irradiated raisins.

  4. Identification of Aspergillus species in Central Europe able to produce G-type aflatoxins.

    PubMed

    Baranyi, Nikolett; Despot, Daniela Jakšić; Palágyi, Andrea; Kiss, Noémi; Kocsubé, Sándor; Szekeres, András; Kecskeméti, Anita; Bencsik, Ottó; Vágvölgyi, Csaba; Klarić, Maja Šegvić; Varga, János

    2015-09-01

    The occurrence of potential aflatoxin producing fungi was examined in various agricultural products and indoor air in Central European countries including Hungary, Serbia and Croatia. For species identification, both morphological and sequence based methods were applied. Aspergillus flavus was detected in several samples including maize, cheese, nuts, spices and indoor air, and several isolates were able to produce aflatoxins. Besides, three other species of Aspergillus section Flavi, A. nomius, A. pseudonomius and A. parasiticus were also isolated from cheese, maize and indoor air, respectively. This is the first report on the occurrence of A. nomius and A. pseudonomius in Central Europe. All A. nomius, A. pseudonomius and A. parasiticus isolates were able to produce aflatoxins B1, B2, G1 and G2. The A. nomius isolate came from cheese produced very high amounts of aflatoxins (above 1 mg ml⁻¹). All A. nomius, A. pseudonomius and A. parasiticus isolates produced much higher amounts of aflatoxin G1 then aflatoxin B1. Further studies are in progress to examine the occurrence of producers of these highly carcinogenic mycotoxins in agricultural products and indoor air in Central Europe.

  5. In vitro activity of terbinafine and itraconazole against Aspergillus species isolated from otomycosis.

    PubMed

    Karaarslan, A; Arikan, S; Ozcan, M; Ozcan, K M

    2004-08-01

    The minimum inhibitory concentrations (MIC, microg ml-1) of itraconazole and terbinafine against overall 34 Aspergillus isolates from the external ear canals with otomycosis have been determined with M38-P microdilution method suggested by National Committee for Clinical Laboratory Standards (NCCLS). MIC intervals in 48 h determined by taking MIC-2 value of itraconazole (the lowest drug concentration causing 50% inhibition of visible fungal growth) and MIC-0 value of terbinafine (the lowest drug concentration causing 100% inhibition of visible fungal growth) as a basis have been found as follows: 0.125-1 and 0.06-0.5 microg ml-1 for A. niger (22 strains), 0.06-0.25 and 0.06-0.125 microg ml-1 for A. flavus (10 strains), 0.125 and 0.125-0.5 microg ml-1 for A. terreus (two strains). It has been observed that both of the antifungal agents showed an in vitro activity against all Aspergillus species tested.

  6. Influence of physical and chemical characteristics of wine grapes on the incidence of Penicillium and Aspergillus fungi in grapes and ochratoxin A in wines.

    PubMed

    Freire, Luísa; Passamani, Fabiana Reinis Franca; Thomas, Ariela Betsy; Nassur, Rita de Cássia Mirela Resende; Silva, Lais Mesquita; Paschoal, Fabiano Narciso; Pereira, Giuliano Elias; Prado, Guilherme; Batista, Luís Roberto

    2017-01-16

    The incidence of filamentous fungi and toxin levels in grapes and wines varies depending on the variety of grapes, the wine region, agricultural practices, weather conditions, the harvest and the winemaking process. In this sense, the objective of this study was to evaluate the diversity of Aspergillus and Penicillium fungi isolated from wine grapes of the semi-arid tropical region of Brazil, evaluate the presence of ochratoxin A (OTA) in the experimental wine and verify if there is a correlation between occurrence of these fungi and the physicochemical characteristics of the wine grapes grown in the region. For the isolation of fungi we used the direct plating technique. The presence of OTA in the experimental wine was detected by high-performance liquid chromatography. The species found were Aspergillus niger, A. carbonarius, A. aculeatus, A. niger Aggregate, A. flavus, A. sojae, Penicillium sclerotiorum, P. citrinum, P. glabrum, P. decumbens, P. solitum and P. implicatum. All isolates of A. carbonarius were OTA producers and all P. citrinum were citrinin producers. The highest concentration of OTA was found in red wine (0.29μg/L). All species identified in this study, except A. flavus, showed a positive correlation with at least one physicochemical parameter assessed, highlighting the pectin content, total sugar, total acidity and phenolic compounds.

  7. Myrmecophilous pygmephoroid mites (Acari: Pygmephoroidea) associated with Lasius flavus (Hymenoptera: Formicidae) in Russia.

    PubMed

    Khaustov, Alexander A

    2015-11-19

    Twenty four species of pygmephoroid mites (Acari: Pygmephoroidea: Neopygmephoridae, Scutacaridae, Microdispidae) are recorded from the ant Lasius flavus (Fabricius) or from its nests from Western Siberia and Crimea. Four of them of the genus Scutacarus Gros, 1845 (Acari: Scutacaridae), S. insolitus sp. nov., S. heterotrichus sp. nov., S. moseri sp. nov. and S. sibiriensis sp. nov. are described as new for science. Four species of scutacarid mites are recorded for the first time in Russia. The comparison of pygmephoroid mite communities associated with Lasius flavus from Crimean and West Siberian populations and notes on phoresy of pygmephoroid mites on ants are provided.

  8. The WOPR Domain Protein OsaA Orchestrates Development in Aspergillus nidulans

    PubMed Central

    Alkahyyat, Fahad; Ni, Min; Kim, Sun Chang; Yu, Jae-Hyuk

    2015-01-01

    Orchestration of cellular growth and development occurs during the life cycle of Aspergillus nidulans. A multi-copy genetic screen intended to unveil novel regulators of development identified the AN6578 locus predicted to encode a protein with the WOPR domain, which is a broadly present fungi-specific DNA-binding motif. Multi-copy of AN6578 disrupted the normal life cycle of the fungus leading to enhanced proliferation of vegetative cells, whereas the deletion resulted in hyper-active sexual fruiting with reduced asexual development (conidiation), thus named as osaA (Orchestrator of Sex and Asex). Further genetic studies indicate that OsaA balances development mainly by repressing sexual development downstream of the velvet regulator VeA. The absence of osaA is sufficient to suppress the veA1 allele leading to the sporulation levels comparable to veA+ wild type (WT). Genome-wide transcriptomic analyses of WT, veA1, and ΔosaA veA1 strains by RNA-Seq further corroborate that OsaA functions in repressing sexual development downstream of VeA. However, OsaA also plays additional roles in controlling development, as the ΔosaA veA1 mutant exhibits precocious and enhanced formation of Hülle cells compared to WT. The OsaA orthologue of Aspergillus flavus is able to complement the osaA null phenotype in A. nidulans, suggesting a conserved role of this group of WOPR domain proteins. In summary, OsaA is an upstream orchestrator of morphological and chemical development in Aspergillus that functions downstream of VeA. PMID:26359867

  9. The Use of the Mounds of Lasius flavus in Teaching Some Principles of Ecological Investigation

    ERIC Educational Resources Information Center

    King, T. J.; Woodell, S. R. J.

    1975-01-01

    Outlines the ecology of Lasius flavus ant hill, describes sampling techniques for the determination of the species composition of the surrounding vegetation, presents a table of typical results from an ant-hill practical, and lists suggestions for further experiments. (GS)

  10. Activity of a long-acting echinocandin, CD101, determined using CLSI and EUCAST reference methods, against Candida and Aspergillus spp., including echinocandin- and azole-resistant isolates

    PubMed Central

    Pfaller, Michael A.; Messer, Shawn A.; Rhomberg, Paul R.; Jones, Ronald N.; Castanheira, Mariana

    2016-01-01

    Objectives The objective of this study was to evaluate the in vitro activity of CD101, a novel echinocandin with a long serum elimination half-life, and comparator (anidulafungin and caspofungin) antifungal agents against a collection of Candida and Aspergillus spp. isolates. Methods CD101 and comparator agents were tested against 106 Candida spp. and 67 Aspergillus spp. isolates, including 27 isolates of Candida harbouring fks hotspot mutations and 12 itraconazole non-WT Aspergillus, using CLSI and EUCAST reference susceptibility broth microdilution (BMD) methods. Results Against WT and fks mutant Candida albicans, Candida glabrata and Candida tropicalis, the activity of CD101 [MIC90 = 0.06, 0.12 and 0.03 mg/L, respectively (CLSI method values)] was comparable to that of anidulafungin (MIC90 = 0.03, 0.12 and 0.03 mg/L, respectively) and caspofungin (MIC90 = 0.12, 0.25 and 0.12 mg/L, respectively). WT Candida krusei isolates were very susceptible to CD101 (MIC = 0.06 mg/L). CD101 activity (MIC50/90 = 1/2 mg/L) was comparable to that of anidulafungin (MIC50/90 = 2/2 mg/L) against Candida parapsilosis. CD101 (MIC mode = 0.06 mg/L for C. glabrata) was 2- to 4-fold more active against fks hotspot mutants than caspofungin (MIC mode = 0.5 mg/L). CD101 was active against Aspergillus fumigatus, Aspergillus terreus, Aspergillus niger and Aspergillus flavus (MEC90 range = ≤0.008–0.03 mg/L). The essential agreement between CLSI and EUCAST methods for CD101 was 92.0%–100.0% among Candida spp. and 95.0%–100.0% among Aspergillus spp. Conclusions The activity of CD101 is comparable to that of other members of the echinocandin class for the prevention and treatment of serious fungal infections. Similar results for CD101 activity versus Candida and Aspergillus spp. may be obtained with either CLSI or EUCAST BMD methods. PMID:27287236

  11. Biocontrol of Aspergillus species on peanut kernels by antifungal diketopiperazine producing Bacillus cereus associated with entomopathogenic nematode.

    PubMed

    Kumar, Sasidharan Nishanth; Sreekala, Sreerag Ravikumar; Chandrasekaran, Dileep; Nambisan, Bala; Anto, Ruby John

    2014-01-01

    The rhabditid entomopathogenic nematode associated Bacillus cereus and the antifungal compounds produced by this bacterium were evaluated for their activity in reducing postharvest decay of peanut kernels caused by Aspergillus species in in vitro and in vivo tests. The results showed that B. cereus had a significant effect on biocontrol effectiveness in in vitro and in vivo conditions. The antifungal compounds produced by the B. cereus were purified using silica gel column chromatography and their structure was elucidated using extensive spectral analyses. The compounds were identified as diketopiperazines (DKPs) [cyclo-(L-Pro-Gly), cyclo(L-Tyr-L-Tyr), cyclo-(L-Phe-Gly) and cyclo(4-hydroxy-L-Pro-L-Trp)]. The antifungal activities of diketopiperazines were studied against five Aspergillus species and best MIC of 2 µg/ml was recorded against A. flavus by cyclo(4-hydroxy-L-Pro-L-Trp). To investigate the potential application of cyclo(4-hydroxy-L-Pro-L-Trp) to eliminate fungal spoilage in food and feed, peanut kernels was used as a food model system. White mycelia and dark/pale green spores of Aspergillus species were observed in the control peanut kernels after 2 days incubation. However the fungal growth was not observed in peanut kernels treated with cyclo(4-hydroxy-L-Pro-L-Trp). The cyclo(4-hydroxy-L-Pro-L-Trp) was nontoxic to two normal cell lines [fore skin (FS) normal fibroblast and African green monkey kidney (VERO)] up to 200 µg/ml in MTT assay. Thus the cyclo(4-hydroxy-L-Pro-L-Trp) identified in this study may be a promising alternative to chemical preservatives as a potential biopreservative agent which prevent fungal growth in food and feed. To the best of our knowledge, this is the first report demonstrating that the entomopathogenic nematode associated B. cereus and cyclo(4-hydroxy-L-Pro-L-Trp) could be used as a biocontrol agents against postharvest fungal disease caused by Aspergillus species.

  12. Ecophysiological characterization of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger isolated from grapes in Spanish vineyards.

    PubMed

    García-Cela, E; Crespo-Sempere, A; Ramos, A J; Sanchis, V; Marin, S

    2014-03-03

    The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from different agroclimatic regions of Spain. Growth characterization (in terms of temperature and water activity requirements) of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium. A. tubingensis and A. niger showed higher maximum temperatures for growth (>45 °C versus 40-42 °C), and lower minimum aw requirements (0.83 aw versus 0.87 aw) than A. carbonarius. No differences in growth boundaries due to their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates from the hotter and drier region grew and produced OTA at lower aw than other isolates. However, little genetic diversity in A. carbonarius was observed for the microsatellites tested and the same sequence of β-tubulin gene was observed; therefore intraspecific variability did not correlate with the geographical origin of the isolates or with their ability to produce OTA. Climatic change prediction points to drier and hotter climatic scenarios where A. tubingensis and A. niger could be even more prevalent over A. carbonarius, since they are better adapted to extreme high temperature and drier conditions.

  13. Monitoring and determination of fungi and mycotoxins in stored Brazil nuts.

    PubMed

    Baquião, Arianne Costa; De Oliveira, Maitê M M; Reis, Tatiana A; Zorzete, Patrícia; Atayde, Danielle D; Corrêa, Benedito

    2013-08-01

    Brazil nut (Bertholletia excelsa) is an important commodity from the Brazilian Amazon, and approximately 37,000 tons (3.36 × 10⁷ kg) of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs, with subsequent production of mycotoxins. In this context, the objective of the present investigation was to evaluate the presence of fungi and mycotoxins (aflatoxins and cyclopiazonic acid) in 110 stored samples of cultivated Brazil nut (55 samples of nuts and 55 samples of shells) collected monthly for 11 months in Itacoatiara, State of Amazonas, Brazil. The samples were inoculated in duplicate onto Aspergillus flavus and Aspergillus parasiticus agar and potato dextrose agar for the detection of fungi, and the presence of mycotoxins was determined by high-performance liquid chromatography. The most prevalent fungi in nuts and shells were Aspergillus spp., Fusarium spp., and Penicillium spp. A polyphasic approach was used for identification of Aspergillus species. Aflatoxins and cyclopiazonic acid were not detected in any of the samples analyzed. The low water activity of the substrate was a determinant factor for the presence of fungi and the absence of aflatoxin in Brazil nut samples. The high frequency of isolation of aflatoxigenic Aspergillus section Flavi strains, mainly A. flavus, and their persistence during storage increase the chances of aflatoxin production on these substrates and indicates the need for good management practices to prevent mycotoxin contamination in Brazil nuts.

  14. Investigation of malic acid production in Aspergillus oryzae under nitrogen starvation conditions.

    PubMed

    Knuf, Christoph; Nookaew, Intawat; Brown, Stephen H; McCulloch, Michael; Berry, Alan; Nielsen, Jens

    2013-10-01

    Malic acid has great potential for replacing petrochemical building blocks in the future. For this application, high yields, rates, and titers are essential in order to sustain a viable biotechnological production process. Natural high-capacity malic acid producers like the malic acid producer Aspergillus flavus have so far been disqualified because of special growth requirements or the production of mycotoxins. As A. oryzae is a very close relative or even an ecotype of A. flavus, it is likely that its high malic acid production capabilities with a generally regarded as safe (GRAS) status may be combined with already existing large-scale fermentation experience. In order to verify the malic acid production potential, two wild-type strains, NRRL3485 and NRRL3488, were compared in shake flasks. As NRRL3488 showed a volumetric production rate twice as high as that of NRRL3485, this strain was selected for further investigation of the influence of two different nitrogen sources on malic acid secretion. The cultivation in lab-scale fermentors resulted in a higher final titer, 30.27 ± 1.05 g liter(-1), using peptone than the one of 22.27 ± 0.46 g liter(-1) obtained when ammonium was used. Through transcriptome analysis, a binding site similar to the one of the Saccharomyces cerevisiae yeast transcription factor Msn2/4 was identified in the upstream regions of glycolytic genes and the cytosolic malic acid production pathway from pyruvate via oxaloacetate to malate, which suggests that malic acid production is a stress response. Furthermore, the pyruvate carboxylase reaction was identified as a target for metabolic engineering, after it was confirmed to be transcriptionally regulated through the correlation of intracellular fluxes and transcriptional changes.

  15. Aspergillus Osteomyelitis of the Skull.

    PubMed

    Nicholson, Simon; King, Richard; Chumas, Paul; Russell, John; Liddington, Mark

    2016-07-01

    Osteomyelitis of the craniofacial skeleton is rare, with fungal pathogens least commonly implicated. The authors present 2 patients of osteomyelitis of the skull caused by Aspergillus spp. and discuss the diagnosis, clinicopathological course, and management strategies.Late recurrence seen in this type of infection warrants long-term follow-up and a high index of suspicion for the clinical signs associated with recurrence.Such patients would benefit from their surgical debridement being planned and managed via a specialist craniofacial unit, so as to utilize the most aesthetically sensitive approach and the experience of specialists from several surgical disciplines.

  16. Two novel species of Aspergillus section Nigri from indoor air

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus collinsii, Aspergillus floridensis, and Aspergillus trinidadensis are described as novel uniseriate species of Aspergillus section Nigri isolated from air samples. To describe the species we used phenotypes from 7-d Czapek yeast extract agar culture (CYA) and malt extract agar culture (M...

  17. Multicenter Study of Method-Dependent Epidemiological Cutoff Values for Detection of Resistance in Candida spp. and Aspergillus spp. to Amphotericin B and Echinocandins for the Etest Agar Diffusion Method.

    PubMed

    Espinel-Ingroff, A; Arendrup, M; Cantón, E; Cordoba, S; Dannaoui, E; García-Rodríguez, J; Gonzalez, G M; Govender, N P; Martin-Mazuelos, E; Lackner, M; Lass-Flörl, C; Linares Sicilia, M J; Rodriguez-Iglesias, M A; Pelaez, T; Shields, R K; Garcia-Effron, G; Guinea, J; Sanguinetti, M; Turnidge, J

    2017-01-01

    Method-dependent Etest epidemiological cutoff values (ECVs) are not available for susceptibility testing of either Candida or Aspergillus species with amphotericin B or echinocandins. In addition, reference caspofungin MICs for Candida spp. are unreliable. Candida and Aspergillus species wild-type (WT) Etest MIC distributions (microorganisms in a species-drug combination with no detectable phenotypic resistance) were established for 4,341 Candida albicans, 113 C. dubliniensis, 1,683 C. glabrata species complex (SC), 709 C. krusei, 767 C. parapsilosis SC, 796 C. tropicalis, 1,637 Aspergillus fumigatus SC, 238 A. flavus SC, 321 A. niger SC, and 247 A. terreus SC isolates. Etest MICs from 15 laboratories (in Argentina, Europe, Mexico, South Africa, and the United States) were pooled to establish Etest ECVs. Anidulafungin, caspofungin, micafungin, and amphotericin B ECVs (in micrograms per milliliter) encompassing ≥97.5% of the statistically modeled population were 0.016, 0.5, 0.03, and 1 for C. albicans; 0.03, 1, 0.03, and 2 for C. glabrata SC; 0.06, 1, 0.25, and 4 for C. krusei; 8, 4, 2, and 2 for C. parapsilosis SC; and 0.03, 1, 0.12, and 2 for C. tropicalis The amphotericin B ECV was 0.25 μg/ml for C. dubliniensis and 2, 8, 2, and 16 μg/ml for the complexes of A. fumigatus, A. flavus, A. niger, and A. terreus, respectively. While anidulafungin Etest ECVs classified 92% of the Candida fks mutants evaluated as non-WT, the performance was lower for caspofungin (75%) and micafungin (84%) cutoffs. Finally, although anidulafungin (as an echinocandin surrogate susceptibility marker) and amphotericin B ECVs should identify Candida and Aspergillus isolates with reduced susceptibility to these agents using the Etest, these ECVs will not categorize a fungal isolate as susceptible or resistant, as breakpoints do.

  18. Natural hybrids of the madtoms, Noturus flavus and Noturus insignis, from the Monongahela River drainage, West Virginia

    USGS Publications Warehouse

    Welsh, S.A.; Cincotta, Dan A.

    2004-01-01

    Natural hybridization is rare in the family Ictaluridae. Putative hybrids of the madtoms Noturus flavus and N. insignis were collected from Blackwater River, Monongahela River drainage, WV. Noturus flavus is native to the Monongahela River drainage, whereas N. insignis is nonnative. We quantified morphological differences among N. flavus, N. insignis, and putative hybrids by sheared principal components analysis of morphometric characters. Putative hybrids were intermediate in tooth patch dimensions, caudal fin pigmentation, length of the dorsal fin base, distance between the adipose/caudal notch and base of caudal fin, and position of anal fin. Hybridization between N. flavus and N. insignis is supported by morphological intermediacy, and may be linked to higher abundances of N. insignis or degraded habitat in the Blackwater River.

  19. Interaction of Wild Strains of Aspergilla with Aspergillus parasiticus ATCC15517 and Aflatoxin Production †

    PubMed Central

    Martins, H. Marina; Almeida, Inês; Marques, Marta; Bernardo, Fernando

    2008-01-01

    Aflatoxins are secondary metabolites produced by some competent mould strains of Aspergillus flavus, A. parasiticus and A. nomius. These compounds have been extensively studied with regards to their toxicity for animals and humans; they are able to induce liver cancer and may cause a wide range of adverse effects in living organisms. Aflatoxins are found as natural contaminants of food and feed; the main line of the strategy to control them is based on the prevention of the mould growth in raw vegetable or during its storage and monitoring of each crop batch. Mould growth is conditioned by many ecological factors, including biotic ones. Hazard characterization models for aflatoxins in crops must take into consideration biotic interactions between moulds and their potential effects on growth development. The aim of this work is to study the effect of the biotic interaction of 14 different wild strains of Aspergilla (different species), with a competent strain (Aspergillus parasiticus ATCC 15517) using an in vitro production model. The laboratory model used was a natural matrix (humidified cracked corn), on which each wild strain challenged the aflatoxin production of a producer strain. Cultures were incubated at 28°C for 12 days and sampled at the 8th and 12th. Aflatoxin detection and quantification was performed by HPLC using a procedure with a MRPL = 1 μg/kg. Results of those interactive cultures revealed both synergic and antagonistic effects on aflatoxin biosynthesis. Productivity increases were particularly evident on the 8th day of incubation with wild strains of A. flavipes (+ 70.4 %), A. versicolor (+ 54.9 %) and A. flavus 3 (+ 62.6 %). Antagonistic effects were found with A. niger (− 69.5%), A. fumigatus (− 47.6 %) and A. terreus (− 47.6 %) on the 12th day. The increased effects were more evident on the 8th of incubation and the decreases were more patent on the 12th day. Results show that the development of Aspergilla strains concomitantly with

  20. Enhancement of Seed Dehiscence by Seed Treatment with Talaromyces flavus GG01 and GG04 in Ginseng (Panax ginseng)

    PubMed Central

    Kim, Min-Jeong; Shim, Chang-Ki; Kim, Yong-Ki; Hong, Sung-Jun; Park, Jong-Ho; Han, Eun-Jung; Kim, Seok-Cheol

    2017-01-01

    Seed dehiscence of ginseng (Panax ginseng C. A. Mayer) is affected by moisture, temperature, storage conditions and microbes. Several microbes were isolated from completely dehisced seed coat of ginseng cultivars, Chunpoong and Younpoong at Gumsan, Korea. We investigated the potential of five Talaromyces flavus isolates from the dehiscence of ginseng seed in four traditional stratification facilities. The isolates showed antagonistic activities against fungal plant pathogens, such as Cylindrocarpon destructans, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia nivalis, Botrytis cinerea, and Phytophthora capsici. The dehiscence ratios of ginseng seed increased more than 33% by treatment of T. flavus GG01, GG02, GG04, GG12, and GG23 in comparison to control (28%). Among the treatments, the reformulating treatment of T. flavus isolates GG01 and GG04 showed the highest of stratification ratio of ginseng seed. After 16 weeks, the reformulating treatment of T. flavus isolates GG01 and GG04 significantly enhanced dehiscence of ginseng seed by about 81% compared to the untreated control. The candidate’s treatment of T. flavus GG01 and GG04 showed the highest decreasing rate of 93% in seed coat hardness for 112 days in dehiscence period. The results suggested that the pre-inoculation of T. flavus GG01 and GG04 found to be very effective applications in improving dehiscence and germination of ginseng seed. PMID:28167883

  1. Influence of herbicide glyphosate on growth and aflatoxin B1 production by Aspergillus section Flavi strains isolated from soil on in vitro assay.

    PubMed

    Barberis, Carla L; Carranza, Cecilia S; Chiacchiera, Stella M; Magnoli, Carina E

    2013-01-01

    The effect of six glyphosate concentrations on growth rate and aflatoxin B1 (AFB1) production by Aspergillus section Flavi strains under different water activity (aW) on maize-based medium was investigated. In general, the lag phase decreased as glyphosate concentration increased and all the strains showed the same behavior at the different conditions tested. The glyphosate increased significantly the growth of all Aspergillus section Flavi strains in different percentages with respect to control depending on pesticide concentration. At 5.0 and 10 mM this fact was more evident; however significant differences between both concentrations were not observed in most strains. Aflatoxin B1 production did not show noticeable differences among different pesticide concentrations assayed at all aW in both strains. This study has shown that these Aspergillus flavus and A. parasiticus strains are able to grow effectively and produce aflatoxins in high nutrient status media over a range of glyphosate concentrations under different water activity conditions.

  2. Evaluation of antifungal activity of free fatty acids methyl esters fraction isolated from Algerian Linum usitatissimum L. seeds against toxigenic Aspergillus

    PubMed Central

    Abdelillah, Amrouche; Houcine, Benmehdi; Halima, Dalile; Meriem, Chabane sari; Imane, Zaaboub; Eddine, Smahi Djamal; Abdallah, Moussaoui; Daoudi, Chabane sari

    2013-01-01

    Objective The aim of this study was to evaluate the antifungal activity of the major fraction of fatty acids methyl esters (FAMEs) isolated from Linum usitatissimum L. seeds oil collected from Bechar department (Algeria). Methods The assessment of antifungal activity was carried out in terms of percentage of radial growth on solid medium (potatoes dextrose agar PDA) and biomass growth inhibition on liquid medium (potatoes dextrose broth PDB) against two fungi. Results The FAMEs was found to be effective in inhibiting the radial mycelial growth of Aspergillus flavus more than Aspergillus ochraceus on all tested concentrations. The highest antifungal index was found to be (54.19%) compared to Aspergillus ochraceus (40.48%). The results of the antifungal activity of the FAMEs inhibition of biomass on liquid medium gave no discounted results, but this does not exclude the antifungal activity. Conclusions We can assume that the observed antifungal potency may be due to the abundance of linoleic and α-linolenic acids in linseed oil which appears to be promising to treat fungal infections, storage fungi and food spoilage in food industry field. PMID:23730556

  3. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species.

    PubMed

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species.

  4. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species

    PubMed Central

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species. PMID:24031186

  5. Inhibition of Aspergillus parasiticus and cancer cells by marine actinomycete strains

    NASA Astrophysics Data System (ADS)

    Li, Ping; Yan, Peisheng

    2014-12-01

    Ten actinomycete strains isolated from the Yellow Sea off China's coasts were identified as belonging to two genera by 16S rDNA phylogenetic analysis: Streptomyces and Nocardiopsis. Six Streptomyces strains (MA10, 2SHXF01-3, MA35, MA05-2, MA05-2-1 and MA08-1) and one Nocardiopsis strain (MA03) were predicted to have the potential to produce aromatic polyketides based on the analysis of the KSα (ketoacyl-synthase) gene in the type II PKS (polyketides synthase) gene cluster. Four strains (MA03, MA01, MA10 and MA05-2) exhibited significant inhibitory effects on mycelia growth (inhibition rate >50%) and subsequent aflatoxin production (inhibition rate >75%) of the mutant aflatoxigenic Aspergillus parasiticus NFRI-95. The ethyl acetate extracts of the broth of these four strains displayed significant inhibitory effects on mycelia growth, and the IC50 values were calculated (MA03: 0.275 mg mL-1, MA01: 0.106 mg mL-1, MA10: 1.345 mg mL-1 and MA05-2: 1.362 mg mL-1). Five strains (2SHXF01-3, MA03, MA05-2, MA01 and MA08-1) were selected based on their high cytotoxic activities. The ethyl acetate extract of the Nocardiopsis strain MA03 was particularly noted for its high antitumor activity against human carcinomas of the cervix (HeLa), lung (A549), kidney (Caki-1) and liver (HepG2) (IC50: 2.890, 1.981, 3.032 and 2.603 μg mL-1, respectively). The extract also remarkably inhibited colony formation of HeLa cells at an extremely low concentration (0.5 μg mL-1). This study highlights that marine-derived actinomycetes are a huge resource of compounds for the biological control of aflatoxin contamination and the development of novel drugs for human carcinomas.

  6. Aspergillus coronary embolization causing acute myocardial infarction.

    PubMed

    Laszewski, M; Trigg, M; de Alarcon, P; Giller, R

    1988-05-01

    An increased frequency of disseminated aspergillosis has been observed in the last decade, mostly occurring in immunocompromised patients including the bone marrow transplant population. Cardiac involvement by Aspergillus remains rare. We report the clinical and postmortem findings of an unusual case of Aspergillus pancarditis in a 7-year-old bone marrow transplant patient with Aspergillus embolization to the coronary arteries leading to a massive acute myocardial infarction. This case suggests that myocardial injury secondary to disseminated aspergillosis should be included in the differential diagnosis of chest pain in the immunocompromised pediatric patient.

  7. Toxic Effects of Modified Fenton Reactions on Xanthobacter flavus FB71†

    PubMed Central

    Büyüksönmez, Fatïh; Hess, Thomas F.; Crawford, Ronald L.; Watts, Richard J.

    1998-01-01

    The toxic effects of modified Fenton reactions on Xanthobacter flavus FB71, measured as microbial survival rates, were determined as part of an investigation of simultaneous abiotic and biotic oxidations of xenobiotic chemicals. A central composite, rotatable experimental design was developed to study the survival rates of X. flavus under various concentrations of hydrogen peroxide and iron(II) and at different initial cell populations. A model based on the experimental results, relating microorganism survival to the variables of peroxide, iron, and cellular concentrations was formulated and fit the data reasonably well, with a coefficient of determination of 0.76. The results of this study indicate that the use of simultaneous abiotic and biotic processes for the treatment of xenobiotic compounds may be possible. PMID:9758796

  8. Conidial Dihydroxynaphthalene Melanin of the Human Pathogenic Fungus Aspergillus fumigatus Interferes with the Host Endocytosis Pathway

    PubMed Central

    Thywißen, Andreas; Heinekamp, Thorsten; Dahse, Hans-Martin; Schmaler-Ripcke, Jeannette; Nietzsche, Sandor; Zipfel, Peter F.; Brakhage, Axel A.

    2011-01-01

    Aspergillus fumigatus is the most important air-borne fungal pathogen of humans. The interaction of the pathogen with the host's immune system represents a key process to understand pathogenicity. For elimination of invading microorganisms, they need to be efficiently phagocytosed and located in acidified phagolysosomes. However, as shown previously, A. fumigatus is able to manipulate the formation of functional phagolysosomes. Here, we demonstrate that in contrast to pigmentless pksP mutant conidia of A. fumigatus, the gray-green wild-type conidia inhibit the acidification of phagolysosomes of alveolar macrophages, monocyte-derived macrophages, and human neutrophil granulocytes. Therefore, this inhibition is independent of the cell type and applies to the major immune effector cells required for defense against A. fumigatus. Studies with melanin ghosts indicate that the inhibitory effect of wild-type conidia is due to their dihydroxynaphthalene (DHN)-melanin covering the conidia, whereas the hydrophobin RodA rodlet layer plays no role in this process. This is also supported by the observation that pksP conidia still exhibit the RodA hydrophobin layer, as shown by scanning electron microscopy. Mutants defective in different steps of the DHN-melanin biosynthesis showed stronger inhibition than pksP mutant conidia but lower inhibition than wild-type conidia. Moreover, A. fumigatus and A. flavus led to a stronger inhibition of phagolysosomal acidification than A. nidulans and A. terreus. These data indicate that a certain type of DHN-melanin that is different in the various Aspergillus species, is required for maximal inhibition of phagolysosomal acidification. Finally, we identified the vacuolar ATPase (vATPase) as potential target for A. fumigatus based on the finding that addition of bafilomycin which inhibits vATPase, led to complete inhibition of the acidification whereas the fusion of phagosomes containing wild-type conidia and lysosomes was not affected. PMID

  9. Conidial Dihydroxynaphthalene Melanin of the Human Pathogenic Fungus Aspergillus fumigatus Interferes with the Host Endocytosis Pathway.

    PubMed

    Thywißen, Andreas; Heinekamp, Thorsten; Dahse, Hans-Martin; Schmaler-Ripcke, Jeannette; Nietzsche, Sandor; Zipfel, Peter F; Brakhage, Axel A

    2011-01-01

    Aspergillus fumigatus is the most important air-borne fungal pathogen of humans. The interaction of the pathogen with the host's immune system represents a key process to understand pathogenicity. For elimination of invading microorganisms, they need to be efficiently phagocytosed and located in acidified phagolysosomes. However, as shown previously, A. fumigatus is able to manipulate the formation of functional phagolysosomes. Here, we demonstrate that in contrast to pigmentless pksP mutant conidia of A. fumigatus, the gray-green wild-type conidia inhibit the acidification of phagolysosomes of alveolar macrophages, monocyte-derived macrophages, and human neutrophil granulocytes. Therefore, this inhibition is independent of the cell type and applies to the major immune effector cells required for defense against A. fumigatus. Studies with melanin ghosts indicate that the inhibitory effect of wild-type conidia is due to their dihydroxynaphthalene (DHN)-melanin covering the conidia, whereas the hydrophobin RodA rodlet layer plays no role in this process. This is also supported by the observation that pksP conidia still exhibit the RodA hydrophobin layer, as shown by scanning electron microscopy. Mutants defective in different steps of the DHN-melanin biosynthesis showed stronger inhibition than pksP mutant conidia but lower inhibition than wild-type conidia. Moreover, A. fumigatus and A. flavus led to a stronger inhibition of phagolysosomal acidification than A. nidulans and A. terreus. These data indicate that a certain type of DHN-melanin that is different in the various Aspergillus species, is required for maximal inhibition of phagolysosomal acidification. Finally, we identified the vacuolar ATPase (vATPase) as potential target for A. fumigatus based on the finding that addition of bafilomycin which inhibits vATPase, led to complete inhibition of the acidification whereas the fusion of phagosomes containing wild-type conidia and lysosomes was not affected.

  10. Aspergillus Infections in Transplant Recipients

    PubMed Central

    Singh, Nina; Paterson, David L.

    2005-01-01

    Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes. PMID:15653818

  11. Three new species of Aspergillus section Flavi isolated from almonds and maize in Portugal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three new aflatoxin-producing species belonging to Aspergillus section Flavi are described, Aspergillus mottae, Aspergillus sergii and Aspergillus transmontanensis. These species were isolated from Portuguese almonds and maize. An investigation examining morphology, extrolites and molecular data was...

  12. Effect of Cymbopogon martinii, Foeniculum vulgare, and Trachyspermum ammi Essential Oils on the Growth and Mycotoxins Production by Aspergillus Species

    PubMed Central

    Woldeamanuel, Yimtubezinash; Asrat, Daniel; Debella, Asfaw

    2014-01-01

    This study was performed to investigate effect of essential oils on Aspergillus spore germination, growth, and mycotoxin production. In vitro antifungal and antiaflatoxigenic activities of Cymbopogon martinii, Foeniculum vulgare, and Trachyspermum ammi essential oils were carried out on toxigenic strains of Aspergillus species. Plant materials were hydrodistilled for 4-5 h in Clevenger apparatus. 0.25 μL/mL, 0.5 μL/mL, 1 μL/mL, 2 μL/mL, and 4 μL/mL concentrations of each essential oil were prepared in 0.1% Tween 80 (V/V). T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 μL/mL by essential oils of T. ammi. The oil also showed complete inhibition of spore germination at a concentration of 2 μL/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting toxin production from A. niger and A. flavus at 0.5 and 0.75 μL/mL, respectively. C. martinii, F. vulgare, and T. ammi oils as antifungals were found superior over synthetic preservative. Moreover, a concentration of 5336.297 μL/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity. In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by Aspergillus species. PMID:26904653

  13. Aspergillus waksmanii sp. nov. and Aspergillus marvanovae sp. nov., two closely related species in section Fumigati

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new and phylogenetically closely related species in Aspergillus section Fumigati are described and illustrated. Homothallic A. waksmanii was isolated from New Jersey soil (USA) and is represented by the ex-type isolate NRRL 179T (=CCF 4266= IBT 31900). Aspergillus marvanovae was isolated from wa...

  14. Aspergillus tubingensis and Aspergillus niger as the dominant black Aspergillus, use of simple PCR-RFLP for preliminary differentiation.

    PubMed

    Mirhendi, H; Zarei, F; Motamedi, M; Nouripour-Sisakht, S

    2016-03-01

    This work aimed to identify the species distribution of common clinical and environmental isolates of black Aspergilli based on simple restriction fragment length polymorphism (RFLP) analysis of the β-tubulin gene. A total of 149 clinical and environmental strains of black Aspergilli were collected and subjected to preliminary morphological examination. Total genomic DNAs were extracted, and PCR was performed to amplify part of the β-tubulin gene. At first, 52 randomly selected samples were species-delineated by sequence analysis. In order to distinguish the most common species, PCR amplicons of 117 black Aspergillus strains were identified by simple PCR-RFLP analysis using the enzyme TasI. Among 52 sequenced isolates, 28 were Aspergillus tubingensis, 21 Aspergillus niger, and the three remaining isolates included Aspergillus uvarum, Aspergillus awamori, and Aspergillus acidus. All 100 environmental and 17 BAL samples subjected to TasI-RFLP analysis of the β-tubulin gene, fell into two groups, consisting of about 59% (n=69) A. tubingensis and 41% (n=48) A. niger. Therefore, the method successfully and rapidly distinguished A. tubingensis and A. niger as the most common species among the clinical and environmental isolates. Although tardy, the Ehrlich test was also able to differentiate A. tubingensis and A. niger according to the yellow color reaction specific to A. niger. A. tubingensis and A. niger are the most common black Aspergillus in both clinical and environmental isolates in Iran. PCR-RFLP using TasI digestion of β-tubulin DNA enables rapid screening for these common species.

  15. Aspergillus brasiliensis sp. nov., a biseriate black Aspergillus species with world-wide distribution.

    PubMed

    Varga, János; Kocsubé, Sándor; Tóth, Beáta; Frisvad, Jens C; Perrone, Giancarlo; Susca, Antonia; Meijer, Martin; Samson, Robert A

    2007-08-01

    A novel species, Aspergillus brasiliensis sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on intergenic transcribed region, beta-tubulin and calmodulin gene sequences, by amplified fragment length polymorphism analysis and by extrolite profiles. A. brasiliensis isolates produced naphtho-gamma-pyrones, tensidol A and B and pyrophen in common with Aspergillus niger and Aspergillus tubingensis, but also several unique compounds, justifying their treatment as representing a separate species. None of the isolates were found to produce ochratoxin A, kotanins, funalenone or pyranonigrins. The novel species was most closely related to A. niger, and was isolated from soil from Brazil, Australia, USA and The Netherlands, and from grape berries from Portugal. The type strain of Aspergillus brasiliensis sp. nov. is CBS 101740(T) (=IMI 381727(T)=IBT 21946(T)).

  16. Stray dogs as reservoirs of the zoonotic agents Leptospira interrogans, Trypanosoma cruzi, and Aspergillus spp. in an urban area of Chiapas in southern Mexico.

    PubMed

    Jimenez-Coello, Matilde; Ortega-Pacheco, Antonio; Guzman-Marin, Eugenia; Guiris-Andrade, Dario M; Martinez-Figueroa, Laura; Acosta-Viana, Karla Y

    2010-03-01

    This investigation determined the presence and prevalence of the zoonotic agents Leptospira interrogans, Trypanosoma cruzi, and Aspergillus spp. in the stray dog population (a total of 224 stray dogs) in an urban area of Southern Mexico. Blood serum samples were taken from all dogs, and root hair samples were taken from dogs with skin lesions and partial alopecia. IgG antibodies for L. interrogans from 10 serovars were detected using the microscopic agglutination test. Immunofluorescence antibody test and Western blot assay were used for serologic diagnosis of T. cruzi. The Sabouraud medium was used to isolate Aspergillus spp. Prevalence of L. interrogans was 4.9%, which was determined by identifying only serovars Pyrogenes, which accounted for 3.6%, and Tarassovi, which constituted 1.3%, with titers from 1:100 to 1:800. Additionally, T. cruzi antibodies were detected in 4.5% of the dogs. Skin lesions were found in 43% of the dogs (98/224), and 35 cultures were positive for Aspergillus spp. (35.7%, p < 0.05, 95% confidence interval 2.45-3.67), identified as A. niger (82.8%), A. flavus (14.3%), and A. terreus (2.9%). This study demonstrates the presence of certain zoonotic agents (bacteria, protozoa, and fungi) in stray dogs living within the studied area. Dogs play an important role in the transmission of diseases that are potentially harmful to humans. Although the prevalence of canine leptospirosis and trypanosomiasis is not high in Southern Mexico compared with other tropical regions of Mexico, the presence of these zoonotic agents in the stray dog population demonstrates that the stray dog population in this region is a significant reservoir and potential source of infection in humans. Special care should be taken when handling stray dogs that exhibit skin lesions with partial alopecia, since a pathological Aspergillus sp. fungus may be present.

  17. Taxonomic Characterization, Evaluation of Toxigenicity, and Saccharification Capability of Aspergillus Section Flavi Isolates from Korean Traditional Wheat-Based Fermentation Starter Nuruk

    PubMed Central

    Bal, Jyotiranjan; Yun, Suk-Hyun; Chun, Jeesun; Kim, Beom-Tae

    2016-01-01

    The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation. This study was performed to classify the most efficient strains of Aspergillus section Flavi isolated from various types of traditional wheat nuruk, based on a polyphasic approach involving molecular and biochemical evaluation. A total of 69 strains were isolated based on colony morphology and identified as Aspergillus oryzae/flavus based on internal transcribed spacer and calmodulin gene sequencing. Interestingly, none were toxigenic based on PCR amplification of intergenic regions of the aflatoxin cluster genes norB-cypA and the absence of aflatoxin in the culture supernatants by thin-layer chromatography analysis. Saccharification capability of the isolates, assessed through α-amylase and glucoamylase activities, revealed that two isolates, TNA24 and TNA15, showed the highest levels of activity. Although the degrees of variation in α-amylase and glucoamylase activities among the isolates were higher, there were only slight differences in acid protease activity among the isolates with two, TNA28 and TNA36, showing the highest activities. Furthermore, statistical analyses showed that α-amylase activity was positively correlated with glucoamylase activity (p < 0.001), and therefore screening for either was sufficient to predict the saccharifying capacity of the Aspergillus strain. PMID:27790066

  18. Wild-Type MIC Distributions and Epidemiological Cutoff Values for the Triazoles and Six Aspergillus spp. for the CLSI Broth Microdilution Method (M38-A2 Document)▿

    PubMed Central

    Espinel-Ingroff, A.; Diekema, D. J.; Fothergill, A.; Johnson, E.; Pelaez, T.; Pfaller, M. A.; Rinaldi, M. G.; Canton, E.; Turnidge, J.

    2010-01-01

    Clinical breakpoints have not been established for mold testing. Wild-type (WT) MIC distributions (organisms in a species/drug combination with no detectable acquired resistance mechanisms) were defined in order to establish epidemiologic cutoff values (ECVs) for five Aspergillus spp. and itraconazole, posaconazole, and voriconazole. Also, we have expanded prior ECV data for Aspergillus fumigatus. The number of available isolates varied according to the species/triazole combination as follows: 1,684 to 2,815 for A. fumigatus, 323 to 592 for A. flavus, 131 to 143 for A. nidulans, 366 to 520 for A. niger, 330 to 462 for A. terreus, and 45 to 84 for A. versicolor. CLSI broth microdilution MIC data gathered in five independent laboratories in Europe and the United States were aggregated for the analyses. ECVs expressed in μg/ml were as follows (percentages of isolates for which MICs were equal to or less than the ECV are in parentheses): A. fumigatus, itraconazole, 1 (98.8%); posaconazole, 0.5 (99.2%); voriconazole, 1 (97.7%); A. flavus, itraconazole, 1 (99.6%); posaconazole, 0.25 (95%); voriconazole, 1 (98.1%); A. nidulans, itraconazole, 1 (95%); posaconazole, 1 (97.7%); voriconazole, 2 (99.3%); A. niger, itraconazole, 2 (100%); posaconazole, 0.5 (96.9%); voriconazole, 2 (99.4%); A. terreus, itraconazole, 1 (100%); posaconazole, 0.5 (99.7%); voriconazole, 1 (99.1%); A. versicolor, itraconazole, 2 (100%); posaconazole, 1 (not applicable); voriconazole, 2 (97.5%). Although ECVs do not predict therapy outcome as clinical breakpoints do, they may aid in detection of azole resistance (non-WT MIC) due to cyp51A mutations, a resistance mechanism in some Aspergillus spp. These ECVs should be considered for inclusion in the future CLSI M38-A2 document revision. PMID:20592159

  19. The Volatome of Aspergillus fumigatus

    PubMed Central

    Calvo, A. M.; Latgé, J. P.

    2014-01-01

    Early detection of invasive aspergillosis is absolutely required for efficient therapy of this fungal infection. The identification of fungal volatiles in patient breath can be an alternative for the detection of Aspergillus fumigatus that still remains problematic. In this work, we investigated the production of volatile organic compounds (VOCs) by A. fumigatus in vitro, and we show that volatile production depends on the nutritional environment. A. fumigatus produces a multiplicity of VOCs, predominantly terpenes and related compounds. The production of sesquiterpenoid compounds was found to be strongly induced by increased iron concentrations and certain drugs, i.e., pravastatin. Terpenes that were always detectable in large amounts were α-pinene, camphene, and limonene, as well as sesquiterpenes, identified as α-bergamotene and β-trans-bergamotene. Other substance classes that were found to be present in the volatome, such as 1-octen-3-ol, 3-octanone, and pyrazines, were found only under specific growth conditions. Drugs that interfere with the terpene biosynthesis pathway influenced the composition of the fungal volatome, and most notably, a block of sesquiterpene biosynthesis by the bisphosphonate alendronate fundamentally changed the VOC composition. Using deletion mutants, we also show that a terpene cyclase and a putative kaurene synthase are essential for the synthesis of volatile terpenes by A. fumigatus. The present analysis of in vitro volatile production by A. fumigatus suggests that VOCs may be used in the diagnosis of infections caused by this fungus. PMID:24906414

  20. Lignin-modifying enzymes of Flavodon flavus, a basidiomycete isolated from a coastal marine environment

    SciTech Connect

    Raghukumar, C.; D`Souza, T.M.; Thorn, R.G.; Reddy, C.A.

    1999-05-01

    A basidiomycetous fungus Flavodon flavus (Klotzsch) Ryvarden (strain 312), isolated from decaying sea grass from a coral lagoon off the west coast of India, mineralized nearly 24% of {sup 14}C-labeled synthetic lignin to {sup 14}CO{sub 2} in 24 days. When grown in low-nitrogen medium this fungus produced three major classes of extracellular lignin-modifying enzymes (LMEs): manganese-dependent peroxidase (MNP), lignin peroxidase (LIP), and laccase. Low MNP and laccase activities were seen in high-nitrogen medium, but no LIP activity was seen. In media containing lignocellulosic substrates such as pine, poplar, or sugarcane bagasse as the sole source of carbon and nitrogen, relatively high MNP and moderate levels of laccases were seen, but LIP production either was not seen or was minimal. LME production was also seen in media prepared with artificial seawater. Fast protein liquid chromatography and isoelectric focusing resolved LMEs into four isozymes each of MNP and LIP, while laccase isozymes were resolved into two groups, one group containing seven isozymes and the other group containing at least three isozymes. The molecular masses of the different isozymes were 43 to 99 kDa for MNP, 40 and 41.5 kDa for LIP, and 43 and 99 kDa for laccase. F. flavus showed effective degradation of various dye pollutants in media prepared with or without artificial seawater. This is the first report on the production of all three major classes of LMEs by F. flavus and points to the bioremediation potential of this organism in terrestrial as well as marine environments.

  1. ASPERGILLUS LUCHUENSIS , AN INDUSTRIALLY IMPORTANT BLACK ASPERGILLUS IN EAST ASIA

    PubMed Central

    Hong, Seung-Beom; Lee, Mina; Kim, Dae-Ho; Varga, Janos; Frisvad, Jens C.; Perrone, Giancarlo; Gomi, Katsuya; Yamada, Osamu; Machida, Masayuki; Houbraken, Jos; Samson, Robert A.

    2013-01-01

    Aspergilli known as black- and white-koji molds which are used for awamori, shochu, makgeolli and other food and beverage fermentations, are reported in the literature as A. luchuensis, A. awamori, A. kawachii, or A. acidus. In order to elucidate the taxonomic position of these species, available ex-type cultures were compared based on morphology and molecular characters. A. luchuensis, A. kawachii and A. acidus showed the same banding patterns in RAPD, and the three species had the same rDNA-ITS, β-tubulin and calmodulin sequences and these differed from those of the closely related A. niger and A. tubingensis. Morphologically, the three species are not significantly different from each other or from A. niger and A. tubingensis. It is concluded that A. luchuensis, A. kawachii and A. acidus are the same species, and A. luchuensis is selected as the correct name based on priority. Strains of A. awamori which are stored in National Research Institute of Brewing in Japan, represent A. niger (n = 14) and A. luchuensis (n = 6). The neotype of A. awamori (CBS 557.65 =  NRRL 4948) does not originate from awamori fermentation and it is shown to be identical with the unknown taxon Aspergillus welwitschiae. Extrolite analysis of strains of A. luchuensis showed that they do not produce mycotoxins and therefore can be considered safe for food and beverage fermentations. A. luchuensis is also frequently isolated from meju and nuruk in Korea and Puerh tea in China and the species is probably common in the fermentation environment of East Asia. A re-description of A. luchuensis is provided because the incomplete data in the original literature. PMID:23723998

  2. [Aspergillus fumigatus endocarditis in a patient with a biventricular pacemaker].

    PubMed

    Cuesta, José M; Fariñas, María C; Rodilla, Irene G; Salesa, Ricardo; de Berrazueta, José R

    2005-05-01

    Aspergillus fumigatus endocarditis is one of the rarest and severest complications in cardiological patients. We describe a patient with an intracardial pacemaker who was diagnosed as having Aspergillus fumigatus endocarditis. Postmortem examination showed a large, Aspergillus-infected thrombus encased in the right ventricle, pulmonary trunk and main pulmonary branches.

  3. Crystallization of engineered Thermus flavus 5S rRNA under earth and microgravity conditions.

    PubMed

    Lorenz, S; Perbandt, M; Lippmann, C; Moore, K; DeLucas, L J; Betzel, C; Erdmann, V A

    2000-04-01

    Thermus flavus 5S rRNA with a molecular weight of about 40 kDa was modified at the 5' and 3' ends. Crystals were obtained under earth and microgravity conditions. The best crystals were obtained during NASA space mission STS 94. For the first time, it was possible to collect a complete data set from 5S rRNA crystals to 7.8 A resolution and to assign the space group as R32, with unit-cell parameters a = b = 110.3, c = 387.6 A, alpha = beta = 90, gamma = 120 degrees.

  4. Response of Tridens flavus (L.) A. S. Hitchc. to soil nutrients and disturbance in an early successional old field

    USGS Publications Warehouse

    Honu, Y.A.K.; Gibson, D.J.; Middleton, B.A.

    2006-01-01

    Soil nutrients and disturbance are two of the main abiotic factors that influence plant dominance (canopy cover), density, and fecundity in early successional old field plant communities. The manner in which the dominant species in old field successional systems respond to the interaction of nutrients and disturbance is poorly known. We examined the dominance, density of flowering tillers, and reproductive output of Tridens flavus, a perennial, warm-season bunchgrass that is important in old field succession, to varying soil nutrient and disturbance regimes. We tested the hypothesis that the interaction between nutrients and disturbance would influence the performance (cover, density, fecundity) of T. flavus. To test this hypothesis, we subjected 25 m2 experimental plots to various combinations of fertilizer and mowing treatments for eight years after initially plowing the field. The performance of T. flavus was measured by estimating percent cover for 8 years (1996-2003) and both density of flowering tillers and reproductive output (panicle length and number of branches per panicle) for three years (2001-2003). The pattern of canopy cover of T. flavus over the first eight years of succession varied over time depending on mowing regime. Dominance was significantly higher in plots that were fertilized only in years one and five than in annually fertilized and unfertilized control plots. The length of panicles and density of flowering tillers were both significantly greater in annually mowed plots than in unmowed plots. In the absence of mowing in particular, T. flavus became overtopped by woody species and declined in this old field community. Therefore, disturbances such as mowing and fertilization may be important in maintaining grasses such as Tridens flavus in old fields.

  5. Aspergillus species cystitis in a cat.

    PubMed

    Adamama-Moraitou, K K; Paitaki, C G; Rallis, T S; Tontis, D

    2001-03-01

    A Persian male cat with a history of lower urinary tract disease was presented because of polydipsia, polyuria, constipation and nasal discharge. Ten weeks before admission, the cat had been treated for lower urinary tract disease by catheterisation and flushing of the bladder. The animal was thin, dehydrated, anaemic and azotaemic. Urine culture revealed Aspergillus species cystitis. Antibodies against Aspergillus nidulans were identified in serum. Fluconazole was administered orally (7.5 mg/kg, q 12 h) for 10 consecutive weeks. The azotaemia was resolved, the kidney concentrating ability was recovered and the cat has remained healthy without similar problems.

  6. Biocontrol of Aspergillus Species on Peanut Kernels by Antifungal Diketopiperazine Producing Bacillus cereus Associated with Entomopathogenic Nematode

    PubMed Central

    Kumar, Sasidharan Nishanth; Sreekala, Sreerag Ravikumar; Chandrasekaran, Dileep; Nambisan, Bala; Anto, Ruby John

    2014-01-01

    The rhabditid entomopathogenic nematode associated Bacillus cereus and the antifungal compounds produced by this bacterium were evaluated for their activity in reducing postharvest decay of peanut kernels caused by Aspergillus species in in vitro and in vivo tests. The results showed that B. cereus had a significant effect on biocontrol effectiveness in in vitro and in vivo conditions. The antifungal compounds produced by the B. cereus were purified using silica gel column chromatography and their structure was elucidated using extensive spectral analyses. The compounds were identified as diketopiperazines (DKPs) [cyclo-(L-Pro-Gly), cyclo(L-Tyr-L-Tyr), cyclo-(L-Phe-Gly) and cyclo(4-hydroxy-L-Pro-L-Trp)]. The antifungal activities of diketopiperazines were studied against five Aspergillus species and best MIC of 2 µg/ml was recorded against A. flavus by cyclo(4-hydroxy-L-Pro-L-Trp). To investigate the potential application of cyclo(4-hydroxy-L-Pro-L-Trp) to eliminate fungal spoilage in food and feed, peanut kernels was used as a food model system. White mycelia and dark/pale green spores of Aspergillus species were observed in the control peanut kernels after 2 days incubation. However the fungal growth was not observed in peanut kernels treated with cyclo(4-hydroxy-L-Pro-L-Trp). The cyclo(4-hydroxy-L-Pro-L-Trp) was nontoxic to two normal cell lines [fore skin (FS) normal fibroblast and African green monkey kidney (VERO)] up to 200 µg/ml in MTT assay. Thus the cyclo(4-hydroxy-L-Pro-L-Trp) identified in this study may be a promising alternative to chemical preservatives as a potential biopreservative agent which prevent fungal growth in food and feed. To the best of our knowledge, this is the first report demonstrating that the entomopathogenic nematode associated B. cereus and cyclo(4-hydroxy-L-Pro-L-Trp) could be used as a biocontrol agents against postharvest fungal disease caused by Aspergillus species. PMID:25157831

  7. Taxonomic Characterization and Secondary Metabolite Profiling of Aspergillus Section Aspergillus Contaminating Feeds and Feedstuffs

    PubMed Central

    Greco, Mariana; Kemppainen, Minna; Pose, Graciela; Pardo, Alejandro

    2015-01-01

    Xerophilic fungal species of the genus Aspergillus are economically highly relevant due to their ability to grow on low water activity substrates causing spoilage of stored goods and animal feeds. These fungi can synthesize a variety of secondary metabolites, many of which show animal toxicity, creating a health risk for food production animals and to humans as final consumers, respectively. Animal feeds used for rabbit, chinchilla and rainbow trout production in Argentina were analysed for the presence of xerophilic Aspergillus section Aspergillus species. High isolation frequencies (>60%) were detected in all the studied rabbit and chinchilla feeds, while the rainbow trout feeds showed lower fungal charge (25%). These section Aspergillus contaminations comprised predominantly five taxa. Twenty isolates were subjected to taxonomic characterization using both ascospore SEM micromorphology and two independent DNA loci sequencing. The secondary metabolite profiles of the isolates were determined qualitatively by HPLC-MS. All the isolates produced neoechinulin A, 17 isolates were positive for cladosporin and echinulin, and 18 were positive for neoechinulin B. Physcion and preechinulin were detected in a minor proportion of the isolates. This is the first report describing the detailed species composition and the secondary metabolite profiles of Aspergillus section Aspergillus contaminating animal feeds. PMID:26364643

  8. Taxonomic Characterization and Secondary Metabolite Profiling of Aspergillus Section Aspergillus Contaminating Feeds and Feedstuffs.

    PubMed

    Greco, Mariana; Kemppainen, Minna; Pose, Graciela; Pardo, Alejandro

    2015-09-02

    Xerophilic fungal species of the genus Aspergillus are economically highly relevant due to their ability to grow on low water activity substrates causing spoilage of stored goods and animal feeds. These fungi can synthesize a variety of secondary metabolites, many of which show animal toxicity, creating a health risk for food production animals and to humans as final consumers, respectively. Animal feeds used for rabbit, chinchilla and rainbow trout production in Argentina were analysed for the presence of xerophilic Aspergillus section Aspergillus species. High isolation frequencies (>60%) were detected in all the studied rabbit and chinchilla feeds, while the rainbow trout feeds showed lower fungal charge (25%). These section Aspergillus contaminations comprised predominantly five taxa. Twenty isolates were subjected to taxonomic characterization using both ascospore SEM micromorphology and two independent DNA loci sequencing. The secondary metabolite profiles of the isolates were determined qualitatively by HPLC-MS. All the isolates produced neoechinulin A, 17 isolates were positive for cladosporin and echinulin, and 18 were positive for neoechinulin B. Physcion and preechinulin were detected in a minor proportion of the isolates. This is the first report describing the detailed species composition and the secondary metabolite profiles of Aspergillus section Aspergillus contaminating animal feeds.

  9. The sexual state of Aspergillus parasiticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sexual state of Aspergillus parasiticus, a potent aflatoxin-producing fungus within section Flavi, is described. The production of nonostiolate ascocarps surrounded by a separate peridium within the stroma places the teleomorph in the genus Petromyces. Petromyces parasiticus differs from P. a...

  10. Kipukasins: Nucleoside derivatives from Aspergillus versicolor.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven new aroyl uridine derivatives (kipukasins A-G; 1-7) were isolated from solid-substrate fermentation cultures of two different Hawaiian isolates of Aspergillus versicolor. The structures of compounds 1-7 were determined by analysis of NMR and MS data. The nucleoside portion of lead compound 1...

  11. Genome sequence of Aspergillus luchuensis NBRC 4314

    PubMed Central

    Yamada, Osamu; Machida, Masayuki; Hosoyama, Akira; Goto, Masatoshi; Takahashi, Toru; Futagami, Taiki; Yamagata, Youhei; Takeuchi, Michio; Kobayashi, Tetsuo; Koike, Hideaki; Abe, Keietsu; Asai, Kiyoshi; Arita, Masanori; Fujita, Nobuyuki; Fukuda, Kazuro; Higa, Ken-ichi; Horikawa, Hiroshi; Ishikawa, Takeaki; Jinno, Koji; Kato, Yumiko; Kirimura, Kohtaro; Mizutani, Osamu; Nakasone, Kaoru; Sano, Motoaki; Shiraishi, Yohei; Tsukahara, Masatoshi; Gomi, Katsuya

    2016-01-01

    Awamori is a traditional distilled beverage made from steamed Thai-Indica rice in Okinawa, Japan. For brewing the liquor, two microbes, local kuro (black) koji mold Aspergillus luchuensis and awamori yeast Saccharomyces cerevisiae are involved. In contrast, that yeasts are used for ethanol fermentation throughout the world, a characteristic of Japanese fermentation industries is the use of Aspergillus molds as a source of enzymes for the maceration and saccharification of raw materials. Here we report the draft genome of a kuro (black) koji mold, A. luchuensis NBRC 4314 (RIB 2604). The total length of nonredundant sequences was nearly 34.7 Mb, comprising approximately 2,300 contigs with 16 telomere-like sequences. In total, 11,691 genes were predicted to encode proteins. Most of the housekeeping genes, such as transcription factors and N-and O-glycosylation system, were conserved with respect to Aspergillus niger and Aspergillus oryzae. An alternative oxidase and acid-stable α-amylase regarding citric acid production and fermentation at a low pH as well as a unique glutamic peptidase were also found in the genome. Furthermore, key biosynthetic gene clusters of ochratoxin A and fumonisin B were absent when compared with A. niger genome, showing the safety of A. luchuensis for food and beverage production. This genome information will facilitate not only comparative genomics with industrial kuro-koji molds, but also molecular breeding of the molds in improvements of awamori fermentation. PMID:27651094

  12. Aspergillus niger contains the cryptic phylogenetic species A. awamori.

    PubMed

    Perrone, Giancarlo; Stea, Gaetano; Epifani, Filomena; Varga, János; Frisvad, Jens C; Samson, Robert A

    2011-11-01

    Aspergillus section Nigri is an important group of species for food and medical mycology, and biotechnology. The Aspergillus niger 'aggregate' represents its most complicated taxonomic subgroup containing eight morphologically indistinguishable taxa: A. niger, Aspergillus tubingensis, Aspergillus acidus, Aspergillus brasiliensis, Aspergillus costaricaensis, Aspergillus lacticoffeatus, Aspergillus piperis, and Aspergillus vadensis. Aspergillus awamori, first described by Nakazawa, has been compared taxonomically with other black aspergilli and recently it has been treated as a synonym of A. niger. Phylogenetic analyses of sequences generated from portions of three genes coding for the proteins β-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species within this population, A. awamori. Morphological, physiological, ecological and chemical data overlap occurred between A. niger and the cryptic A. awamori, however the splitting of these two species was also supported by AFLP analysis of the full genome. Isolates in both phylospecies can produce the mycotoxins ochratoxin A and fumonisin B₂, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-γ-pyrones. In addition, sequence analysis of four putative A. awamori strains from Japan, used in the koji industrial fermentation, revealed that none of these strains belong to the A. awamori phylospecies.

  13. Thermal and optical characterization of biologically synthesized ZnS nanoparticles synthesized from an endophytic fungus Aspergillus flavus: A colorimetric probe in metal detection

    NASA Astrophysics Data System (ADS)

    Uddandarao, Priyanka; Balakrishnan, Raj Mohan

    2017-03-01

    Nanostructured semiconductor materials are of great importance for several technological applications due to their optical and thermal properties. The design and fabrication of metal sulfide nanoparticles with tunable properties for advanced applications have drawn a great deal of attention in the field of nanotechnology. ZnS is a potential II-IV group material which is used in hetero-junction solar cells, light emitting diodes, optoelectronic devices, electro luminescent devices and photovoltaic cells. Due to their multiple applications, there is a need to elucidate their thermal and optical properties. In the present study, thermal and optical properties of biologically synthesized ZnS nanoparticles are determined in detail with Thermal Gravimetric Analysis (TGA), Derivative Thermogravimetric Analysis (DTG), Differential Scanning Calorimeter (DSC), Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL) and Raman spectroscopy. The results reveal that ZnS NPs exhibit a very strong quantum confinement with a significant increase in their optical band gap energy. These biologically synthesized ZnS NPs contain protein residues that can selectively bind with metal ions in aqueous solutions and can exhibit an aggregation-induced color change. This phenomenon is utilized to quantitatively measure the metal concentrations of Cu2 + and Mn2 + in this study. Further the stability of nanoparticles for the metal sensing process is accessed by UV-Vis spectrometer, zeta potential and cyclic voltammeter. The selectivity and sensitivity of ZnS NPs indicate its potential use as a sensor for metal detection in the ecosystem.

  14. Genome-wide analysis of the Zn(II)2Cys6 zinc cluster-encoding gene family in Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteins with a Zn(II)2Cys6 domain, Cys-X2-Cys-X6-Cys-X5-12-Cys-X2-Cys-X6-9-Cys (hereafter, referred to as the C6 domain), form a subclass of zinc finger proteins found exclusively in fungi and yeast. Genome sequence databases of Saccharomyces cerevisiae and Candida albicans have provided an overvie...

  15. Reduction of IgE binding and nonpromotion of Aspergillus flavus fungal growth by simultaneously silencing Ara h 2 and Ara h 6 in peanut.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most potent peanut allergens, Ara h 2 and 6, were silenced in transgenic plants by RNA interference. Three independent transgenic lines were recovered after microprojectile bombardment, of which two contained single, integrated copies of the transgene. The third line contained multiple copies ...

  16. Behavioural development, fat reserves and their association with productivity in Lasius flavus founding queens

    NASA Astrophysics Data System (ADS)

    Norman, V. C.; Pamminger, T.; Hughes, W. O. H.

    2016-04-01

    Reproduction-related behaviours are key components determining individual fitness. Many behavioural traits are linked, and such trait associations often affect fitness. Here, we combine behavioural and physiological data during two critical time points of founding queens (early and late nest-founding stage) in the claustral ant Lasius flavus to assess how these factors affect their initial productivity. We show that most behavioural traits, except brood care behaviour, are plastic during queen development and demonstrate that there are alternative behavioural pathways to achieve high productivity under standardised conditions. These results indicate that queens can utilise multiple behavioural trait combinations to maximise reproductive output at the earliest, and arguably most critical, time of colony foundation.

  17. Antimicrobial Activity of Biocompatible Microemulsions Against Aspergillus niger and Herpes Simplex Virus Type 2

    PubMed Central

    Alkhatib, Mayson H; Aly, Magda M; Rahbeni, Rajaa A; Balamash, Khadijah S

    2016-01-01

    Background Microemulsions (MEs), which consist of oil, water, surfactants, and cosurfactants, have recently generated considerable interest as antimicrobial agents. Objectives To determine the antifungal and antiviral activities of three ME formulations (MEa, MEb, and MEc) that differ in their hydrophilicity. Methods The ME formulas were produced by mixing different fractions of Tween 80, Span 20, ethanol, oil, isopropyl myristate, and distilled water. The antifungal activity of the ME formulas against Aspergillus niger, A. flavus, Bacillus, Candida albicans, and C. glabrata were determined by the solid medium diffusion cytotoxicity test against the mitochondria, measuring the minimum inhibitory concentration, dry biomass, and leakage of potassium, and characterizing the cell morphology. The antiviral activities of the ME formulas against the herpes simplex virus type 2 (HSV-2) were determined using the cytopathic effect assay. Results Significant antimicrobial activities were recorded against A. niger and herpes simplex virus type 2 (HSV-2) when treated with MEb that had hydrophobic nanodroplets with an average diameter of 4.7 ± 1.22 nm. A volume of 0.1 mL of MEb (10 mL of potato dextrose broth) inhibited the germination of A. niger cells, reduced their dry biomass, enhanced the leakage of potassium from the cell membranes, affected their mitochondria, and altered the shape of their conidia, in addition to enlarging them. MEb was able to destroy the HSV-2 virus at a 200-fold dilution in Dulbecco’s modified eagle medium. Conclusions The water-in-oil ME with equivalent surfactant-to-oil ratio (MEb) has great potential as an antifungal and antiviral agent. PMID:27800146

  18. Novel fungal FAD glucose dehydrogenase derived from Aspergillus niger for glucose enzyme sensor strips.

    PubMed

    Sode, Koji; Loew, Noya; Ohnishi, Yosuke; Tsuruta, Hayato; Mori, Kazushige; Kojima, Katsuhiro; Tsugawa, Wakako; LaBelle, Jeffrey T; Klonoff, David C

    2017-01-15

    In this study, a novel fungus FAD dependent glucose dehydrogenase, derived from Aspergillus niger (AnGDH), was characterized. This enzyme's potential for the use as the enzyme for blood glucose monitor enzyme sensor strips was evaluated, especially by investigating the effect of the presence of xylose during glucose measurements. The substrate specificity of AnGDH towards glucose was investigated, and only xylose was found as a competing substrate. The specific catalytic efficiency for xylose compared to glucose was 1.8%. The specific activity of AnGDH for xylose at 5mM concentration compared to glucose was 3.5%. No other sugars were used as substrate by this enzyme. The superior substrate specificity of AnGDH was also demonstrated in the performance of enzyme sensor strips. The impact of spiking xylose in a sample with physiological glucose concentrations on the sensor signals was investigated, and it was found that enzyme sensor strips using AnGDH were not affected at all by 5mM (75mg/dL) xylose. This is the first report of an enzyme sensor strip using a fungus derived FADGDH, which did not show any positive bias at a therapeutic level xylose concentration on the signal for a glucose sample. This clearly indicates the superiority of AnGDH over other conventionally used fungi derived FADGDHs in the application for SMBG sensor strips. The negligible activity of AnGDH towards xylose was also explained on the basis of a 3D structural model, which was compared to the 3D structures of A. flavus derived FADGDH and of two glucose oxidases.

  19. Assessment of Cymbopogon citratus (DC.) stapf essential oil as herbal preservatives based on antifungal, antiaflatoxin, and antiochratoxin activities and in vivo efficacy during storage.

    PubMed

    Sonker, Nivedita; Pandey, Abhay K; Singh, Pooja; Tripathi, N N

    2014-04-01

    Thirty-five randomly collected samples of stored table grapes (Vitis vinifera L.) from different markets of Gorakhpur city, Uttar Pradesh, India, revealed occurrence of 11 types of fungi. Of which, Aspergillus flavus, Aspergillus niger, and Aspergillus ochraceus were dominant causing severe decay of grapes with 58%, 52%, and 67% incidence, respectively. On screening of 15 essential oils at 0.33 μL/mL, Cymbopogon citratus oil caused 100% mycelial inhibition against aforesaid dominant fungi. Oil was fungistatic at 0.29 μL/mL and exhibited broad fungitoxicity against other fruit rotting fungi associated with collected samples. C. citratus oil completely inhibited the growth and mycotoxin (AFB1 and OTA) secretion of the aflatoxigenic and ochratoxigenic strains of A. flavus, A. niger, and A. ochraceus at 0.8 μL/mL. E-Citral (52.9%) and Z-Citral (39.38%) were the major components of C. citratus oil during gas chromatography and gas chromatography-mass spectrometry analysis. Application of 200 and 300 μL of C. citratus oil on 1 kg of stored grapes showed enhancement of shelf life up to 10 d. The oil did not exhibit any phytotoxic effect on fruits. These results confirm that C. citratus oil could be a natural alternative to commercial fungicide for control of fruit rotting fungi of stored grapes.

  20. Microbiological and aflatoxin evaluation of Brazil nut pods and the effects of unit processing operations.

    PubMed

    Arrus, Katia; Blank, Greg; Clear, Randall; Holley, Richard A; Abramson, David

    2005-05-01

    Harvesting of Brazil nuts not only helps to preserve the Amazon rainforest but also provides income to individuals who would otherwise have little means of making a livelihood. Recently, the European Community has tightened the quality requirements for Brazil nuts, particularly with regard to aflatoxin levels and microbiological contamination. The objectives of this research were to gain a better understanding of the origin of aflatoxins on Brazil nuts and to microbiologically evaluate some of the operations involved in processing. In this regard, five Brazil nut pods were aseptically picked from trees located in each of three concessions of the Peruvian Amazon rainforest (Madre de Dios province). The exteriors of the pods and the nuts were examined for yeast and molds, including Aspergillus flavus and Aspergillus parasiticus, and for bacteria, including Salmonella and Escherichia coli. Brazil nuts obtained from various commercial process operations located in Peru were similarly evaluated. Exteriors of all Brazil nut pods did not contain A. parasiticus, and only pods from one concession yielded A. flavus isolates. All isolates tested were aflatoxigenic (630 to 915 ppb total aflatoxin). Coliforms, E. coli, and salmonellae were not recovered from any of the pods. Whole, in-shell nuts obtained after opening the pods yielded no A. flavus or A. parasiticus. Aflatoxins were not detected (detection limit 1.75 ppb) in any of the nuts. Whole, in-shell and shelled nuts from various process operations were all positive for A. flavus but negative for E. coli and salmonellae. Soaking of whole, in-shell nuts before cracking or shelling increased coliform numbers, whereas levels of A. flavus decreased. In order to gain a better understanding of the sanitary performance of the unit process operations, additional evaluations should be conducted on product lots processed on different days. Also, the microbiology of product processed from common lots should be followed through the