Flavus Isolate Research Articles

Bacteria-mediated green synthesis of silver nanoparticles and their antifungal potentials against Aspergillus flavus.

The best biocontroller Bacillus subtilis produced silver nanoparticles (AgNPs) with a spherical form and a 62 nm size through green synthesis. Using UV-vis spectroscopy, PSA, and zeta potential analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy, the properties of synthesized silver nanoparticles were determined. Silver nanoparticles were tested for their antifungicidal efficacy against the most virulent isolate of the Aspergillus flavus fungus, JAM-JKB-BHA-GG20, and among the 10 different treatments, the treatment T6 [PDA + 1 ml of NP (19: 1)] + Pathogen was shown to be extremely significant (82.53%). TG-51 and GG-22 were found to be the most sensitive groundnut varieties after 5 and 10 days of LC-MS QTOF infection when 25 different groundnut varieties were screened using the most toxic Aspergillus flavus isolate JAM- JKB-BHA-GG20, respectively. In this research, the most susceptible groundnut cultivar, designated GG-22, was tested. Because less aflatoxin (1651.15 g.kg-1) was observed, treatment T8 (Seed + Pathogen + 2 ml silver nanoparticles) was determined to be much more effective. The treated samples were examined by Inductively Coupled Plasma Mass Spectrometry for the detection of metal ions and the fungicide carbendazim. Ag particles (0.8 g/g-1) and the fungicide carbendazim (0.025 g/g-1) were found during Inductively Coupled Plasma Mass Spectrometry analysis below detectable levels. To protect plants against the invasion of fungal pathogens, environmentally friendly green silver nanoparticle antagonists with antifungal properties were able to prevent the synthesis of mycotoxin by up to 82.53%.

Preliminary study for evaluation of some fungicides against Aspergillus flavus isolated from historical illuminated paper manuscript dated back to the Mamluk period

Various valuable illuminated paper manuscripts in museums and libraries suffer from fungal deterioration. The treatment and protection of illuminated paper manuscripts from fungal damage is an important process. Therefore, the current study aimed to evaluate different fungicides against fungi isolated from historical illuminated paper manuscript dated back to the Mamluk period (1250–1516 AD). Fungi isolated from infected historical illuminated paper manuscripts were identified and their cellulolytic enzyme activity was performed. The identified fungi were A. fumigatus, A. niger, A. flavus, Alternaria alternate, and Trichoderma sp. Isolate (4-1), identified as Aspergillus flavus, possessed the highest cellulase activity. This isolate was tested against the following fungicides: azoxystrobin, boscalid, difenoconazole, dimethomorph, propiconazole, pyraclostrobin, and thiophanate-methyl at concentrations from 1 to 200 ppm, nanoparticles of TiO2 and SiO2 at concentrations of 0.5%, and 1% and mixtures of fungicides [difenoconazole + propiconazole (1:1)] at 100 and 200 ppm and [boscalid + pyraclostrobin (2:1)] at 150 and 300 ppm. The disc diffusion method (DDM) was used to evaluate the efficiency of the prepared individual and mixed fungicides against Aspergillus flavus (4-1) isolate. The results of this study revealed that treatments with individual difenoconazole at 200 ppm exhibited the best antifungal activity, followed by the propiconazole fungicide. Further research is needed to evaluate the in vitro practical application of these fungicides with infected illuminated paper samples with Aspergillus flavus agents in the field.

Morphed aflaxotin concentration produced by Aspergillus flavus strain VKMN22 on maize grains inoculated on agar culture

This study identified and monitored the levels of aflatoxins (B1 and B2) produced by Aspergillus flavus isolate VKMN22 (OP355447) in maize samples sourced from a local shop in Johannesburg, South Africa. Maize samples underwent controlled incubation after initial rinsing, and isolates were identified through morphological and molecular methods. In another experiment, autoclaved maize grains were intentionally re-inoculated with the identified fungal isolate using spore suspension (106 spore/mL), after which 1 g of the contaminated maize sample was inoculated on PDA media and cultured for seven days. The aflatoxin concentrations in the A. flavus contaminated maize inoculated on culture media was monitored over seven weeks and then measured using liquid chromatography–mass spectroscopy (LC-MS). Results confirmed the successful isolation of A. flavus strain VKMN22 with accession number OP355447, which consistently produced higher levels of AFB1 compared to AFB2. AF concentrations increased from week one to five, then declined in week six and seven. AFB1 levels ranged from 594.3 to 9295.33 µg/kg (week 1–5) and then reduced from 5719.67 to 2005 µg/kg in week six and seven), while AFB2 levels ranged from 4.92 to 901.67 µg/kg (weeks 1–5) and then degraded to 184 µg/kg in week six then 55.33 µg/kg (weeks 6–7). Levene's tests confirmed significantly higher mean concentrations of AFB1 compared to AFB2 (p ≤ 0.005). The study emphasizes the importance of consistent biomonitoring for a dynamic understanding of AF contamination, informing accurate prevention and control strategies in agricultural commodities thereby safeguarding food safety.

Telomere-to-telomere genome assembly of the aflatoxin biocontrol agent Aspergillus flavus isolate La3279 isolated from maize in Nigeria.

Here, we report the complete genome of the non-aflatoxigenic Aspergillus flavus isolate La3279, which is an active ingredient of the aflatoxin biocontrol product Aflasafe. The chromosome-scale assembly clarifies the deletion pattern in the aflatoxin biosynthesis gene cluster and corrects a misidentified assembly previously published for this isolate.

Microscopic fungi of wheat grain in the Polissya zone

The article presents the data on the quantitative and qualitative composition of micromycetes of wheat grain grown in the Polissya region. During the research period, an average of 2.88-104 ± 3.62-103 colony forming units (CFU) per 1 g of grain was found in wheat grain samples collected in the Polissya region. Twenty species of microscopic fungi belonging to 9 genera were isolated from the wheat grain of the Polissya zone. Among them were the genera Alternaria (92.5 %), Mucor (92.5 %), Aspergillus (83.0 %), Penicillium (47.2 %), Fusarium (60.4 %), Phoma (15,.1 %), Mycelia (15.1 %), Trichotecium (1.9 %) and Monascus (1.9 %) of the samples. Aspergillus niger (17.0 %), Aspergillus candidus (9.4 %), and Aspergillus terreus (1.9 %) were detected less frequently among Aspergillus. Fusarium spp. (17.0 %), Fusarium oxysporum, Fusarium moniliforme, Fusarium semitectum in (5.7 %), and Fusarium culmorum (3.8 %) of the samples were identified among Fusarium. A smaller number of microscopic fungi species represents the endophytic mycobiota of wheat grain. Among the isolates of micromycetes isolated from the Polissya zone, pure cultures were obtained from F. sporotrichiella var. tricinctum isolate 1218/4, and F. sporotrichiella isolate 1218/5. These isolates were atoxic against the test culture Candida pseudotropicalis strain 44 PC, but F. sporotrichiella var. tricinctum 1218/4 produced a growth retardation zone with Rf 0.05 and produced an unidentified trichothecene mycotoxin (TTMT). Among the isolated fungi, Aspergillus flavus isolate 1219/3 and Aspergillus flavus isolate 1221/1 were the first to produce kojic and aspergillic acids and the second to synthesize penicillic and aspergillic acids. To reduce the negative effect of the mycotoxin deoxynivalenol on the body of chickens of the meat and egg breed Adler Silver, the birds were fed the sorbent “Mikosorb”. It was found that when added to the diet, the sorbent “Mikosorb” in the amount of 2.0 % of the total feed weight reduces the negative effect of deoxynivalenol on the body of chickens of the experimental group. This was confirmed by a 12.0 % reduction in bird mortality. Feeding “Microsorb” in the amount of 2.0 % by weight of complete feed contributed to an increase in the average daily weight gain of poultry during the experiment by 5.43 % compared to the experimental group that consumed feed with the toxin deoxynivalenol (DON). During the experiment, the birds of the experimental group No. 2 consumed 28.91 kg of feed more than group No. 2. Feeding the sorbent “Mikosorb” in the amount of 2.0 % of the feed weight to chickens of the meat and egg breed Adler silver contributes to an increase in gross weight gain by 9.69 kg during the experiment. The use of “Mikosorb” in the technology of feeding chickens of experimental group No. 2 contributed to an increase in the profitability of poultry production by up to 12.0 % compared to poultry that consumed feed affected by DON toxin. After analyzing the scientific results from the literature and our research results, we concluded that the abovementioned studies on wheat grain should be carried out throughout Ukraine during harvesting and storage in warehouses or storages.

Cocoa-associated filamentous fungi for the biocontrol of aflatoxigenic Aspergillus flavus.

Aflatoxin and other mycotoxin contamination are major threats to global food security and present an urgent need to secure the global food crop against spoilage by mycotoxigenic fungi. Cocoa material is noted for naturally low aflatoxin contamination. This study was designed to assess the potential for harnessing cocoa-associated filamentous fungi for the biocontrol of aflatoxigenic Aspergillus flavus. The candidate fungi were isolated from fermented cocoa beans collected from four cocoa-growing areas in Ghana. Molecular characterization included Internal Transcribed Spacer (ITS)-sequencing for identification and polymer chain reaction (PCR) to determine mating type. Effects of the candidate isolates on growth and aflatoxin-production by an aflatoxigenic A. flavus isolate (BANGA1) were assessed. Aflatoxin production was monitored by UV fluorescence and quantified by enzyme-linked immunosorbent assay (ELISA). Thirty-six filamentous fungi were cultured and identified as Aspergillus, Cladosporium, Lichtheimia, or Trichoderma spp. isolates. The isolates generally interacted negatively with BANGA1 growth and aflatoxin production. The Aspergillus niger and Aspergillus aculeatus biocontrol candidates showed the strongest colony antagonism (54%-94%) and reduction in aflatoxin production (12%-50%) on agar. In broth, the A. niger isolates reduced aflatoxin production by up to 97%. Metabolites from the A. niger isolates showed the strongest inhibition of growth by BANGA1 and inhibited aflatoxin production. Four of the candidate isolates belonged to the MAT1-1 mating type and 12 identified as MAT1-2. This may be indicative of the potential for genetic recombination events between fungi in the field, a finding which is particularly relevant to the risk posed by A. flavus biocontrol measures that rely on atoxigenic A. flavus strains.

Combining ability of experimental maize lines for yield and aflatoxin in the southeastern United States

AbstractAflatoxin contamination of maize (Zea mays L.) grain presents risks to animal and human health and causes economic losses for growers, particularly in the southeastern United States. Development of hybrids with genetic resistance to aflatoxin contamination by Aspergillus flavus will reduce these risks. Two factorial crossing experiments were conducted to evaluate yield, agronomic traits, and aflatoxin in maize hybrids. In Experiment 1, 18 aflatoxin‐resistant (GT) lines were each crossed to six testers. In Experiment 2, 13 of the same lines were each crossed to 10 different testers. Each experiment was conducted for 2 years at Tifton, GA, and commercial check hybrids were included for comparison. Ears were inoculated with A. flavus isolate NRRL 3357 using the side‐needle technique 14 days after silking. Aflatoxin was quantified after harvest. Broad sense heritability for aflatoxin was low in Experiment 1 (H2 = 0.09) but was higher in Experiment 2 (H2 = 0.27). Heritability was moderate to high for plant height (H2 = 0.49–0.51) and days to silking (H2 = 0.54–0.72). Among experimental lines, GT1209 and GT1309 had consistent positive general combining ability (GCA) for yield, whereas GT1203 and GT1204 had consistent negative (favorable) GCA for aflatoxin. Significant GCA effects, both positive and negative, for aflatoxin were also observed among testers in both experiments. Some experimental hybrids had yields that were comparable to commercial checks while also having lower aflatoxin, demonstrating the progress made in improvement of both traits in maize hybrids adapted to the Southern United States.

Deciphering of seed Health of common food grains (wheat, rice) of North Eastern UP and Gurgaon Haryana, India

The stored random samples of food seeds of wheat and rice (60 samples) were purchased from places of Eastern UP and Gurgaon district Haryana. Its moisture contents were estimated. The Mycological investigations of wheat seeds revealed presence of a total number of 16 fungal species viz., Alternaria alternata, Aspergillus candidus, Aspergillus flavus, A. niger, A. ochraceous, A. phoenicis, A. tamari, A. terreus, A. sydowi, Fusarium moniliforme, F. oxysporum F. solani, P. glabrum, Rhizopus nigricans, Trichoderma viride and Trichothecium roseum. While mycological analysis of rice seeds showed presence of 15 fungal species viz., Alternaria padwickii, A. oryzae, Curvularia lunata, Fusarium moniliforme, Aspergillus clavatus, A. flavus, A. niger, Cladosporium sp., Nigrospora oryzae, Alternaria tenuissima, Chaetomium globosum, F. solani, Microascus cirrosus, Helminthosporium oryzae, Pyricularia grisea. It also projected variation in presence of fungal species in blotter and agar plate method of analysis. In wheat Blotter method of analysis showed 16 fungal species while agar plate depicted 13 fungal species. In rice Agar plate method depicted presence of 15 fungal species while blotter method shows presence of 12 fungal species. The insect analysis revealed that wheat samples were infected with Tribolium castaneum. While rice seeds sample showed presence of insect Sitophilus oryzae. The investigations revealed that Aspergillus flavus, A. niger, Sitophilus oryzae and Tribolium castaneum caused reduction in seed weight loss, seed germination, carbohydrate and protein contents of common food grains (wheat, rice). It also revealed that randomly selected A. flavus isolate 1 of wheat showed higher potential of aflatoxin B1 production (1392.940 μg/l) while rice isolate 2 showed 1231.117 μg/l production.

Impacts of Temperature and Water Activity Interactions on Growth, Aflatoxin B1 Production and Expression of Major Biosynthetic Genes of AFB1 in Aspergillus flavus Isolates.

The contamination of peanuts, with Aspergillus flavus and subsequent aflatoxins (AFs) is considered to be one of the most serious, safety problems in the world. Water activity (aw) and temperature are limiting, factors for fungal growth and aflatoxin production during storage. The objectives of this study were to integrate data on the effects of temperature (34, 37, and 42 °C) and water activity (aw; 0.85, 0.90, and 0.95) on growth rate aflatoxin B1 (AFB1) production and up- or-downregulation of the molecular expression of biosynthetic AFB1 genes divided into three types based on their A. flavus isolate composition and AFB1 capacity in vitro: A. flavus KSU114 (high producer), A. flavus KSU114 (low producer), and A. flavus KSU121 (non-producer). The A. flavus isolates were shown to be resilient in terms of growth on yeast extract sucrose agar media when exposed to temperature and water activity as pivotal environmental factors. The optimal conditions for the fungal growth of three isolates were a temperature of 34 °C and water activity of 0.95 aw; there was very slow fungal growth at the highest temperature of 42 °C, with different aw values causing inhibited fungal growth. The AFB1 production for the three isolates followed the same pattern with one exception: A. flavus KSU114 failed to produce any AFB1 at 42 °C with different aw values. All tested genes of A. flavus were significantly up- or downregulated under three levels of interaction between temperature and aw. The late structural genes of the pathway were significantly upregulated at 34 °C under aw 0.95, although aflR, aflS and most of the early structural genes were upregulated. Compared to 34 °C with an aw value of 0.95, most of the expressed genes were significantly downregulated at 37 and 42 °C with aw values of 0.85 and 0.90. Additionally, two regulatory genes were downregulated under the same conditions. The expression level of laeA was also completely associated with AFB1 production, while the expression level of brlA was linked to A. flavus colonization. This information is required to forecast the actual effects of climate change on A. flavus. The findings can be applied to improve specific food technology processes and create prevention strategies to limit the concentrations of potential carcinogenic substances in peanuts and their derivatives.

A novel pressed coal from citrus and cooking oil wastes using fungi

Nowadays renewable energy with low prices is a global target that has taken the attention to compare alternatives energy sources with fossil fuels. Therefore, this study was established to find suitable and sustainable alternative low-cost fuels source. Cooking oil waste (COW) was mixed with non-pretreated citrus tree fibers (CTF) (0.5 mL to 1 g ratio) and pressed to formulate coal (CTF/COW). Otherwise, this mixture was subjected to in situ fungal pretreated using Aspergillus flavus isolate to simplify the mixture composition and pressed to offer in a usable form with enhancing their heating value for the first time. CTF/COW was characterized using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM) and thermal analysis (TGA) before and after treatment. The fungal isolate was observed with enzyme productivity and activity of CMCase, avicelase, xylanase, mannanase, α-glucosidase, β-glucosidase, lignin peroxidase and lipase according to enzyme assays and the chemical compositions of CTF before and after fungal treatment, where the best PH for enzymes extraction was between 5 and 7. The fungal enzymes increased the heating value by about two and half folds in comparison with non-pretreated coal. Moreover, the calorific value of tCTF/COW was 43,422 kJ/kg, which was higher than CTF recorded 18,214 kJ/kg and COW recorded 39,823 kJ/kg. Our result suggests that fungal treatment of the mixture of citrus trees and cooking oil waste presents as a promising low-cost and eco-friendly coal.Graphical

Molecular Identification of Aspergillus flavus isolated from some maize (Zea mays L.) varieties across Abuja, Nigeria

This study aims at isolating and molecularly characterizing Aspergillus flavus from maize (Zea mays L.) varieties (Samaz 15,20, 37, 52, Oba super 6, 9, 39, 98, and DK 777) obtained across Abuja, Nigeria. Maize varieties were obtained across the district areas of Abuja namely; Kuje, Kwali, Gwagalada, AMAC, Abaji, Bwari and UniAbuja Experimental field. The potato dextrose agar as a medium was used in growing the fungi from the maize varieties seeds for 7 days at 25oC and then sub-cultured to obtain an isolate into potato dextrose broth. The mycelial mass produced was processed to extract its DNA using genomic DNA extraction of Zymo, D6005 for fungi and bacteria. Molecular Identification of the Internal transcribed spacer (ITS) region for each A. flavus isolate was carried out with ITS1 and ITS4 primers. anf18S rRNA gene region was also amplified with ITS5 and ITS4 primers. 2.0% agarose gels were electrophoresed for 30 minutes in 0.5× buffer, Dye and 60 mM EDTA at 80 V. A gel documentation system was used in determining PCR product sizes by evaluating with internal Mol. Wt. Standards of Thermo Scientific GeneRuler 100 bp DNA Ladder. Fifteen (15) of the twenty (20) fungal isolates were found to be positive with PCR amplification of ITS regions and amplicon sizes of 600 base pairs (bp) for A. flavus were obtained. All the twenty isolates have the presence of 18S rRNA 300-400bp. Thirteen of the fungal growth from the fourteen maize varieties obtained across Abuja were identified as A. flavus.

Lessons Learned: the Importance of Biological Curation.

Proper species identification of sequenced fungal isolates or strains is imperative for the interpretation of genomics data. Through this letter (1), and through another recently published research note (2), it has come to our attention that one of the isolates presented in our previous publication (3) was misidentified. The presumptive Aspergillus parasiticus isolate NRRL 2999 has been shown to be an Aspergillus flavus isolate, a clonal derivative of A. flavus NRRL 3357 (2). In our recent publication presenting two new reference genomes for A. flavus (4), we performed a phylogenomics analysis of several publicly available Aspergillus assemblies and noted the sequence similarity between A. flavus NRRL 3357 and A. parasiticus NRRL 2999. We also noted a close relationship between A. flavus WRRL 1519 and A. oryzae RIB40 and that A. oryzae RIB40 grouped among A. flavus isolates, not as an outgroup. Based on these analyses, we concluded that the A. flavus species is polyphyletic. The revelation that NRRL 2999 is indeed an A. flavus isolate clonal to NRRL 3357 (2) does point toward A. flavus as a distinct species from A. parasiticus but does not change the conclusion of the potential polyphyletic nature of A. flavus based on the position of A. oryzae in the analysis (4). All additional conclusions were based on phylogenetic relationships defined within the scope of the manuscript (4) and were therefore independent of species labels.

Production of monoclonal antibodies against AFLM (Ver-1), a middle key protein involved in aflatoxin biosynthesis

Aflatoxins are potent carcinogens, mutagens and teratogens, and are harmful to both humans and animals. As many as 30 genes are involved in aflatoxin biosynthesis. Among them, aflM (ver-1) gene was predicted to encode a 28-kDa NADPH-dependent ketoreductase (AFLM), which catalyzed middle enzymatic steps in aflatoxin biosynthetic pathway. AFLM (Ver-1) was proved to be necessary for conversion of versicolorin A (VERA) to demethylsterigmatocystin (DMST) in aflatoxin B1 (AFB1) biosynthesis. For these reasons, aflM gene was cloned and specific monoclonal antibodies for AFLM was developed to better define potential pathways of AFLM involved in AFB1 biosynthesis. Monoclonal antibodies 11B2-1D7 and 3G5-4E7 were successfully screened out by immunizing mouse. Immunoblot analysis revealed that both had high sensitivity and specificity to identify native AFLM protein in A. flavus with detection limit of 11 ​ng/mL and 8 ​ng/mL respectively. These results showed that it was suitable for quantitative detection of AFLM in A. flavus isolate. Further investigation revealed that aflatoxin accumulations of various A. flavus were not dependent on AFLM biosynthesis. Overall, this is the first report for development for AFLM monoclonal antibody development and application in A. flavus quantitative detection.

The Elevated Endogenous Reactive Oxygen Species Contribute to the Sensitivity of the Amphotericin B-Resistant Isolate of Aspergillus flavus to Triazoles and Echinocandins.

Aspergillus flavus has been frequently reported as the second cause of invasive aspergillosis (IA), as well as the leading cause in certain tropical countries. Amphotericin B (AMB) is a clinically important therapy option for a range of invasive fungal infections including invasive aspergillosis, and in vitro resistance to AMB was associated with poor outcomes in IA patients treated with AMB. Compared with the AMB-susceptible isolates of A. terreus, the AMB-resistant isolates of A. terreus showed a lower level of AMB-induced endogenous reactive oxygen species (ROS), which was an important cause of AMB resistance. In this study, we obtained one AMB-resistant isolate of A. flavus, with an AMB MIC of 32 μg/mL, which was sensitive to triazoles and echinocandins. This isolate presented elevated endogenous ROS levels, which strongly suggested that no contribution of decreased AMB-induced endogenous ROS for AMB-resistance, opposite to those observed in A. terreus. Further, we confirmed that the elevated endogenous ROS contributed to the sensitivity of the AMB-resistant A. flavus isolate to triazoles and echinocandins. Further investigation is needed to elucidate the causes of elevated endogenous ROS and the resistance mechanism to AMB in A. flavus.

Chromosome assembled and annotated genome sequence of Aspergillus flavus NRRL 3357.

Aspergillus flavus is an opportunistic pathogen of crops, including peanuts and maize, and is the second leading cause of aspergillosis in immunocompromised patients. A. flavus is also a major producer of the mycotoxin, aflatoxin, a potent carcinogen, which results in significant crop losses annually. The A. flavus isolate NRRL 3357 was originally isolated from peanut and has been used as a model organism for understanding the regulation and production of secondary metabolites, such as aflatoxin. A draft genome of NRRL 3357 was previously constructed, enabling the development of molecular tools and for understanding population biology of this particular species. Here, we describe an updated, near complete, telomere-to-telomere assembly and re-annotation of the eight chromosomes of A. flavus NRRL 3357 genome, accomplished via long-read PacBio and Oxford Nanopore technologies combined with Illumina short-read sequencing. A total of 13,715 protein-coding genes were predicted. Using RNA-seq data, a significant improvement was achieved in predicted 5’ and 3’ untranslated regions, which were incorporated into the new gene models.

Evaluate the Antifungal and detoxification activity of silver nanoparticles prepared with the Curcuma plant extract against Aflatoxin B1 in broiler feed.

The research was carried out in the laboratories of the Ministry of Science and Technology/Iraq. Green nanoparticles were prepared using turmeric (Curcuma plant) extracted by using biological methods and were characterized by using some techniques including Scanning Electron Microscopy (SEM), X-ray Diffractometer (XRD) and zeta potential Analyzer. The results showed that the spherical particles were shown individually or in the aggregate, crystalline, and the value zeta voltage at -33.22 mV. The inhibition activity of green nanoparticles was tested against Aspergillus flavus growth and compared with Basten fungicide as a comparison treatment and negative control sample. The results of nanoparticles showed high inhibitor activity in the 590.33 ppm concentration compared to negative control and comparative treatment in concentration 750 ppm. Feeds contaminated with A. flavus isolate were treated with cur. AgNPs at 590.33 ppm for a four-week (incubation period) and Aflatoxin B1. The results showed no Aflatoxin in feed samples were treated with nanoparticles while showing Aflatoxin B1 at a concentration of 38 ppb in control samples. To study the effect of cur. AgNPs against the fungal toxicity in meat broilers feeding to feeding contaminated with Aflatoxin B1 by using some blood and histopathological signs of bird’s liver. The results showed the nanoparticles treatment samples significant superiority compared with the positive control (contaminated with Aflatoxin B1) (p ≤0.01), and no significant differences with control treatment (feed free from any addition). We conclude that the use of green nanoparticles (Curcuma longa L.) produced by biological method as good alternatives to fungicides that harmful to public health and inhibitory activity of A. flavus and prevent the production of Aflatoxin B1 and improve the blood and histopathological signs of birds.

Molecular Identification and Antifungal Susceptibility of Yeasts and Molds Isolated from Patients with Otomycosis.

Fungal otitis externa, an infection of the external auditory canal caused by molds and yeasts, accounts for approximately 10-20% of ear canal infections accompanying high recurrence. The purpose of the current study was to assess the pattern of etiological agents of otomycosis and resistance profile as well as the rate of tympanic membrane perforation. A total of 1040 patients with symptoms of fungal otitis externa, in a period of two years, were investigated. The mycological tests revealed the presence of different fungi in 237 ears (22.8%). Fungal otitis was more related to filamentous fungi of the species Aspergillus flavus (54.43%), A. tubingensis (10.97%), and A. niger (8.86%), followed by yeasts, Candida orthopsilosis (7.59%), C. albicans (6.75%), and C. parapsilosis (5.06%). Tympanic membrane perforation rate was found to be 6.75% and was more common with otomycosis caused by A. flavus, A. tubingensis and C. albicans. In antifungal susceptibility tests, all tested drugs showed generally good activity against most isolates of molds and yeasts, while tolnaftate, clotrimazole, nystatin, and terbinafine had lowest effects. We found that among Aspergillus isolates, one A. niger isolate was resistant to voriconazole, and one A. flavus isolate was resistant to amphotericin B. Furthermore, among Candida species, three isolates of C. orthopsilosis showed high MIC values to fluconazole, two C. albicans isolates were considered fluconazole resistant and one isolate of C. parapsilosis was resistant to caspofungin and 3 isolates were resistant to fluconazole. Regarding the existence of the cases with perforated tympanic membrane and emerging species causing fungal otitis in the current report, the importance of the early physical examination, precise molecular identification, and the antifungal susceptibility evaluation is highlighted.

Biosynthesis and Bio-sensing Applications of Silver and Gold Metal Nanoparticles

Biogenic nanoparticles have gained major interest because of their eco-friendly approach, as non-toxic chemicals are involved in the biosynthesis, and the preparation process carried out at ambient pressure and temperature. In the present study, two fungal strains (MM1and MM2) showed the ability to biosynthesize silver and gold nanoparticles, respectively, were isolated from local Egyptian soil samples. These two fungi were identified by the molecular technique 18srRNA as Aspergillus terreus isolate MM1-EGY and Aspergillus flavus isolate MM2-EGY. The biosynthesized silver nanoparticles by Aspergillus terreus isolate MM1-EGY exhibited UV absorbance around 420 nm and particle size range of 15-35 nm as measured by transmission electron microscopy (TEM). On the other hand, gold nanoparticles biosynthesized by Aspergillus flavus isolate MM2-EGY showed maximum UV/Vis absorbance around 550 nm and size range of 20-50 nm. The XRD of both AgNPs and AuNPS was constructed. The green synthesized gold nanoparticles were tested for sensitive and selective simultaneous voltammetric determination of neurotransmitter metabolite, vanillylmandelic acid (VMA) and homovanillic acids (HVA), while silver nanoparticles were applied for the fabrication of disposable screen-printed Ag/AgCl planner reference electrode.

Morphological and Molecular Characterization of Toxigenic Aspergillus flavus from Groundnut Kernels in Kenya.

Pathogenesis of Aspergillus flavus on important agricultural products is a key concern on human health due to the synthesis and secretion of the hazardous secondary metabolite, aflatoxin. This study identified and further characterized aflatoxigenic A. flavus from groundnuts sampled from sundry shops in Kenya using integrated morphological and molecular approaches. The groundnuts were plated on potato dextrose agar for isolation and morphological observation of A. flavus based on macroscopic and microscopic features. Molecular characterization was done through amplification and comparison of the partial sequence of the ITS1-5.8S-ITS2 region. The expression analysis of aflR, aflS, aflD, aflP, and aflQ genes in the aflatoxin biosynthesis pathways was conducted to confirm the positive identification of A. flavus. The gene expression also aided to delineate toxigenic isolates of A. flavus from atoxigenic ones. Morphologically, 18 isolates suspected to be A. flavus were identified. Out of these, 14 isolates successfully amplified the 500 bp ITS region of A. flavus or Aspergillus oryzae, while 4 isolates were not amplified. All the remaining 14 isolates expressed at least one of the aflatoxigenic genes but only 5 had all the genes expressed. Partial sequencing revealed that isolates 5, 11, 12, 13, and 15 had 99.2%, 97.6%, 98.4%, 97.5%, and 100% homology, respectively, to the A. flavus isolate LUOHE, ITS-5.8S-ITS2, obtained from the NCBI database. The five isolates were accurate identification of atoxigenic A. flavus. Precise identification of toxigenic strains of A. flavus will be useful in establishing control strategies of the fungus in food products.

BIOSYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF IRON OXIDE NANOPARTICLES SYNTHESIZED BY FUNGI

In the present study, extracellular synthesis of iron oxide nanoparticles (FeNPs) was achieved byAspergillus flavus isolate D05.The biosynthesized iron oxide nanoparticles have been widely favored because of biodegradablity, low toxicity and highly reactive surfaces. IONPs were synthesized through the reduction of aqueous Fe3+ ions. The obtained iron oxide nanoparticles were characterized by UV-vis spectroscopy, Fourier transforms infrared spectroscopy(FTIR), and Transmission electron microscope (TEM). TEM image of iron nanoparticles synthesized byAspergillus flavus sp. showed 28-33 nm sized particles.