scholarly journals Detection of Aflatoxigenic and Non-Aflatoxigenic Isolates of Aspergillus flavus Isolated From Some Clinical and Environmental Sources by HPLC and PCR Techniques

2018 ◽  
Vol 12 (1) ◽  
pp. 40-48
Author(s):  
Mushtak T.S. Al-Ouqaili ◽  
Mohammed H. Muslih ◽  
Salah M. A. Al-Kubaisi
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Target Genes ◽  
High Efficiency ◽  
High Sensitivity ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Genes Encoding ◽  
Hplc Technique

This study aimed to determine the role of polymerase chain reaction (PCR) and High-performance liquid chromatography (HPLC) technique in the discrimination between aflatoxigenic and non-aflatoxigenic isolates of Aspergillus flavus. The isolates were identified based on macroscopical and microscopical characteristics, and extracted aflatoxin was detected by HPLC technique. Furthermore, DNA was extracted from the all isolates and carried out by PCR to amplify target genes encoding for toxin production (nor-1, ver-1 and aflR). The results showed that the genes (aflR, nor-1) were found in 11 (73%) of isolates, while the (ver-1) gene appeared in 10 (67%) of isolates. Both aflatoxigenic and non-aflatoxigenic isolates were also determined depending on the amplification of gene sites in the targeted DNA. HPLC technique has also used with high efficiency to ensure the aflatoxin-producing isolates and to evaluate the level of aflatoxin B1 production for 15 isolates of A. flavus. Ten isolates were able to produce aflatoxin with rates ranged from 0.78 to 45.03 ppm. PCR technique has proved high efficiency in the differentiation between aflatoxigenic and non-aflatoxigenic isolates of A. flavus. Moreover, aflatoxin production was directly associated with gene appearance and gene detection. Also, HPLC technique is a standard and superb technique in identifying and analyzing aflatoxin with high sensitivity and accuracy.

scholarly journals Investigation of the Antifungal and Anti-Aflatoxigenic Potential of Plant-Based Essential Oils against Aspergillus flavus in Peanuts

2020 ◽  
Vol 6 (4) ◽  
pp. 383
Author(s):  
Premila Narayana Achar ◽  
Pham Quyen ◽  
Emmanuel C. Adukwu ◽  
Abhishek Sharma ◽  
Huggins Zephaniah Msimanga ◽  
...  
Keyword(s):  
Essential Oils ◽  
Aspergillus Flavus ◽  
High Performance ◽  
Opportunistic Infections ◽  
Aflatoxin Production ◽  
The United States ◽  
Microscopy Study ◽  
Aspergillus Species ◽  
Gas Chromatography Mass Spectrometry ◽  
Ammonia Vapor

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts.

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

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

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

scholarly journals Regulation of Morphology, Aflatoxin Production, and Virulence of Aspergillus flavus by the Major Nitrogen Regulatory Gene areA

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 718 ◽  
Author(s):  
Opemipo Esther Fasoyin ◽  
Kunlong Yang ◽  
Mengguang Qiu ◽  
Bin Wang ◽  
Sen Wang ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Regulatory Gene ◽  
Nitrogen Sources ◽  
Aflatoxin Production ◽  
Fungal Species ◽  
Complete Medium ◽  
Over Expression ◽  
Oxidative Stresses ◽  
Gata Transcription Factor

Aspergillus flavus is a renowned plant, animal and human pathogen. areA is a global nitrogen regulatory gene of the GATA transcription factor family, shown to be the major nitrogen regulator. In this study, we identified areA in A. flavus and studied its function. The AreA protein contained a signatory zinc finger domain, which is extremely conserved across fungal species. Gene deletion (ΔareA) and over-expression (OE::areA) strains were constructed by homologous recombination to elucidate the role of areA in A. flavus. The ΔareA strain was unable to efficiently utilize secondary nitrogen sources for growth of A. flavus, and it had poorly developed conidiophores, when observed on complete medium, resulting in the production of significantly less conidia than the wild-type strain (WT). Aflatoxin B1 (AFB1) production was reduced in ΔareA compared with the WT strain in most conditions tested, and ΔareA had impaired virulence in peanut seeds. areA also played important roles in the sensitivity of A. flavus to osmotic, cell wall and oxidative stresses. Hence, areA was found to be important for the growth, aflatoxin production and pathogenicity of A. flavus. This work sheds light on the function of areA in the regulation of the nitrogen metabolism of A. flavus, and consequently aims at providing new ways for controlling the crossover pathogen, A. flavus.

scholarly journals WHEEZE RECOGNITION BASED ON 2D BILATERAL FILTERING OF SPECTROGRAM

2006 ◽  
Vol 18 (03) ◽  
pp. 128-137 ◽  
Author(s):  
BOR-SHING LIN ◽  
BOR-SHYH LIN ◽  
HUEY-DONG WU ◽  
FOK-CHING CHONG ◽  
SAO-JIE CHEN
Keyword(s):  
High Performance ◽  
Analog Circuit ◽  
High Efficiency ◽  
Low Cost ◽  
High Sensitivity ◽  
Bilateral Filter ◽  
Recognition System ◽  
Detection Algorithm ◽  
Respiratory Sounds ◽  
Edge Preserving

This paper describes the design of a low-cost and high performance wheeze recognition system. First, respiratory sounds are captured, amplified and filtered by an analog circuit; then digitized through a PC soundcard, and recorded in accordance with the Computerized Respiratory Sound Analysis (CORSA) standards. Since the proposed wheeze detection algorithm is based on the spectrogram processing of respiratory sounds, spectrograms generated from recorded sounds have to pass through a 2D bilateral filter for edge-preserving smoothing. Finally, the processed spectra go through an edge detection procedure to recognize wheeze sounds.Experiment results show a high sensitivity of 0.967 and a specificity of 0.909 in qualitative analysis of wheeze recognition. Due to its high efficiency, great performance and easy-to-implement features, this wheeze recognition system could be of interest in the clinical monitoring of asthma patients and the study of physiological mechanisms in the respiratory airways.

Influence of refrigeration on aflatoxin production by strains of Aspergillus flavus

1969 ◽  
Vol 15 (6) ◽  
pp. 629-632 ◽  
Author(s):  
W. van Walbeek ◽  
T. Clademenos ◽  
F. S. Thatcher
Keyword(s):  
Aspergillus Flavus ◽  
Room Temperature ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Experimental Conditions ◽  
Liquid Cultures ◽  
High Concentrations

Strains of Aspergillus flavus that produce high concentrations of aflatoxin in cultures incubated at room temperature also produced these toxins in significant concentrations under conditions simulating household refrigeration (7.5° to 10 °C). The rate of toxin production at 10 °C was markedly influenced by preincubating cultures at room temperature for 24 hours. Solid cultures yielded higher concentrations of toxin than liquid cultures under the prevailing experimental conditions.

Effect of Laminarin on Aspergillus Flavus Growth and Aflatoxin Production

2011 ◽  
Vol 343-344 ◽  
pp. 1168-1171 ◽  
Author(s):  
Liang Bin Hu ◽  
Hong Bo Li ◽  
Jun Liang Sun ◽  
Jie Zeng
Keyword(s):  
Liquid Medium ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Biological Activities ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Aflatoxin Contamination ◽  
Laminaria Digitata ◽  
Inhibitory Effects ◽  
Mycelium Growth

Control of aflatoxin contamination has been a worldwide problem. Laminarin from Laminaria digitata is one kind of polysaccharides with multiple biological activities. In this paper, the inhibitory effects of Laminarin on the growth and toxin production of A. flavus was studied. The results indicated that 150 and 200 µg/mL of Laminarin ccould significantly inhibit the aflatoxin production in Sabouraud liquid medium (Sab), without affecting mycelium growth. In addition, the results also showed that certain concentration Laminaria could decrease the infection of peanut seeds by A. flavus as well as the contamination by aflatoxin B1.

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

2016 ◽  
Vol 9 (5) ◽  
pp. 665-672 ◽  
Author(s):  
M.K. Gilbert ◽  
B.M. Mack ◽  
G.A. Payne ◽  
D. Bhatnagar
Keyword(s):  
Climate Change ◽  
Functional Genomics ◽  
Aspergillus Flavus ◽  
Pathogenic Fungus ◽  
Regulatory Gene ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Transcriptomic Response ◽  
Climate Conditions ◽  
Change Impact

Aspergillus flavus is an opportunistic and pathogenic fungus that infects several crops of agricultural importance and under certain conditions may produce carcinogenic mycotoxins. Rising global temperatures, disrupted precipitation patterns and increased CO2 levels that are associated with future climate conditions are expected to impact the growth and toxigenic potential of A. flavus. Both laboratory and real world observations have demonstrated this potential, especially when examining the effects of water availability and temperature. Recent experiments have also established that CO2 may also be affecting toxin production. The application of current technologies in the field of functional genomics, including genomic sequencing, RNA-seq, microarray technologies and proteomics have revealed climate change-related, abiotic regulation of the aflatoxin cluster and influence on the plant-fungus interaction. Furthermore, elevated CO2 levels have been shown to impact expression of the aflatoxin biosynthetic regulatory gene aflR. The use of functional genomics will allow researchers to better understand the underlying transcriptomic response within the fungus to climate change, with a view towards predicting changes in fungal infection and toxin production associated with climate change.

scholarly journals MIR822 modulates monosporic female gametogenesis through an ARGONAUTE9-dependent pathway in Arabidopsis thaliana

2021 ◽  
Author(s):  
ANDREA TOVAR AGUILAR ◽  
Daniel GRIMANELLI ◽  
Gerardo Acosta Garcia ◽  
Jean Philippe Vielle Calzada ◽  
Jesus Agustin Badillo-Corona ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Flowering Plants ◽  
Loss Of Function ◽  
Genes Encoding ◽  
Functional Megaspore ◽  
Dependent Pathway ◽  
Female Gametogenesis

In the ovule of flowering plants, the establishment of the haploid generation occurs when a somatic cell differentiates into a Megaspore Mother Cell (MMC) and initiates meiosis. As most flowering plants, Arabidopsis thaliana undergoes a monosporic type of gametogenesis; three meiotically derived cells degenerate without further division, and a single one, the functional megaspore (FM), divides mitotically to form the female gametophyte. In Arabidopsis, the ARGONAUTE4 clade proteins are involved in the control of megasporogenesis. In particular, mutations in ARGONAUTE9 (AGO9) lead to the ectopic differentiation of gametic precursors that can give rise female gametophytes. However, the genetic basis and molecular mechanisms that control monosporic gametogenesis remain largely unknown. Here, we show that Arabidopsis plants carrying loss-of-function mutations in the AGO9-interacting miR822a give rise to extranumerary surviving megaspores that acquire a FM identity and divide without giving rise to differentiated female gametophytes. The overexpression of three miR822a target genes encoding Cysteine/Histidine-Rich C1 domain proteins (DC1) phenocopy mir822a plants. The miR822a targets are overexpressed in ago9 mutant ovules, confirming that miR822a acts through an AGO9-dependent pathway to negatively regulate DC1 domain proteins. Our results identify a new role of miRNAs in the most prevalent form of female gametogenesis in flowering plants

scholarly journals Mycotoxigenic Aspergillus flavus from ginger and turmeric consumed in the Niger Delta Region of Nigeria

1970 ◽  
Vol 27 (2) ◽  
pp. 151
Author(s):  
V C Okereke, M I Godwin-Egein
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Uv Light ◽  
Aflatoxin Production ◽  
Malt Extract ◽  
Blue Fluorescence ◽  
Toxigenic Fungi ◽  
Orange Yellow ◽  
Southern Nigeria ◽  
Yellow Pigmentation

Ginger and turmeric sold in the open markets and retail outlets in southern Nigeria were sampled between April and August, 2017. This period coincided with the first bimodal peak of the rainy season of the 2017 cropping season. Malt extract agar (MEA) and Dichloran 18% glycerol (DG18) media were used to isolate fungi from samples with or without surface sterilisation. Aspergillus spp isolated were examined for the production of orange-yellow pigmentation and blue fluorescence on the reverse side of the plate on CAM under UV light. Aflatoxin production by Aspergillus flavus on yeast extract sucrose (YES) was verified quantitatively using High Performance Liquid Chromatography (HPLC). Data showed that Fusarium, Penicillium and Aspergillus spp were the dominant fungal flora. Toxigenic isolates of A. flavus; AFg1, AFg3, AFt1, and AFt3 produced both orange-yellow pigmentation and blue fluorescence on CAM. The production of AFB1 and AFB2 on YES medium was confirmed using HPLC. The occurrence of toxigenic fungi indicates that there is a potential risk of mycotoxin contamination in ginger and turmeric consumed in southern Nigeria and problems can arise from contamination with aflatoxins.

Maturation of TonEBP expression in developing rat kidney

2004 ◽  
Vol 287 (5) ◽  
pp. F878-F885 ◽  
Author(s):  
Ki-Hwan Han ◽  
Seung Kyoon Woo ◽  
Wan-Young Kim ◽  
Soo-Hyun Park ◽  
Jung-Ho Cha ◽  
...  
Keyword(s):  
Target Genes ◽  
Kidney Development ◽  
Rat Kidney ◽  
Renal Medulla ◽  
Organic Osmolytes ◽  
Vasa Recta ◽  
Enhancer Binding Protein ◽  
Genes Encoding ◽  
Urinary Concentrating Ability

Tonicity-responsive enhancer binding protein (TonEBP) is a transcriptional activator of the Rel family. In the renal medulla, TonEBP stimulates genes encoding proteins involved in cellular accumulation of organic osmolytes, the vasopressin-regulated urea transporters (UT-A), and heat shock protein 70. To understand the role of TonEBP in the development of urinary concentrating ability, TonEBP expression during rat kidney development was investigated. In embryonic kidneys, TonEBP immunoreactivity was detected 16 days postcoitus in the cytoplasm of the endothelial cells surrounding the medullary collecting ducts (MCD). By 20 days, TonEBP was detected in most tubular profiles in the medulla, including the loop of Henle and MCD, and interstitial cells. The intensity of TonEBP immunoreactivity was much higher in the vasa recta than the tubules. In addition, immunoreactivity was localized predominantly to the cytoplasm. On postnatal day 1, two major changes were observed. TonEBP immunoreactivity shifted to the nucleus, and the intensity of TonEBP immunoreactivity of the tubules increased dramatically. These changes were associated with an increase in TonEBP and sodium- myo-inositol cotransporter mRNA abundance. Thereafter, TonEBP expression in tubular profiles increased moderately. The adult pattern of TonEBP expression was established at postnatal day 21 coincident with full maturation of the renal medulla. Thus expression of TonEBP in developing kidneys occurred predominantly in the medulla and preceded expression of its target genes, including UT-A. These data suggest that TonEBP contributes to the development of urine-concentrating ability.

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