Aspergillus Flavus Var Research Articles

Compilation of secondary metabolites produced by fungal strains identified as Aspergillus flavus var. oryzae (formerly Aspergillus oryzae), with a review of biotechnological applications, and computational studies of their anti-COVID-19 activity

Compilation of secondary metabolites produced by fungal strains identified as Aspergillus flavus var. oryzae (formerly Aspergillus oryzae), with a review of biotechnological applications, and computational studies of their anti-COVID-19 activity

Phylogenetic Analysis Of Endophytic Fungi Isolate from Bellucia pentamera Naudin Based On ITS rDNA

Endophytic fungi can produce secondary metabolites of endophytic fungi isolated from host plants. The purpose of this study is to identify and analyze the sequencing of endophytic fungi isolates with ITS and Beta-tubulin markers and phylogenetic trees. The endophytic fungi isolate DKJ1, DKJ3a, DKJ3c and DKJ4 were successfully isolated from the cardia plant (Bellucia pentamera Naudin) indicated by Aspergillus niger group, Aspergillus fumigatus group and Penicillium sp. The results of the sequencing analysis of isolates DKJ1, DKJ3a, DKJ3c, and DKJ4 were successfully amplified with an annealing temperature of 54ºC with a pair of ITS1-ITS4 primers with a molecular weight of 570 bp and a Beta-Tubulin primer with an annealing temperature of 56.1ºC molecular weight of 550 bp. From the results of identification and analysis of DNA sequencing of endophytic fungi DKJ1, DKJ3a, DKJ3c and DKJ4 with the primary pair of ITS and Beta-tubulin shows that the phylogenetic tree is different from the species obtained. ITS DKJ1 isolates have similarities with the species Aspergillus piperis CBS 112811, ITS DKJ3c has similarities with the species Aspergillus flavus var flavus strain ATCC 16833, ITS DKJ3a has similarities with Penicillium rolfsii strain NRRL 1078 species and ITS DKJ4 has similarities with Penicillium oxalicum NRRL 787 species. Whereas isolate from DKJ1 Beta-Tubulin has similarities with NRRL 4875 Aspergillus tubingensis species, DKJ3c has similarities with species of Aspergillus novoparasiticus strain DTO 223-C4 and DKJ4 has a similarity with Penicillium guaibinensis species. But there are similarities based on Cluster A (Aspergillus Group) and Cluster B (Penicillium Group) on phylogenetic trees.

Optimization of inulinase production by a newly isolated strain Aspergillus flavus var. flavus by solid state fermentation of Saccharum arundinaceum

Abstract The present study deals with the use of mangrove soil, a new source for the isolation of an inulinase producing strain followed by the enzyme production and optimization using hardy sugarcane, “Saccharum arundinaceum”, a novel substrate. Four fungal isolates were obtained from the primary screening in inulin media. In the secondary screening, only Aspergillus flavus var. flavus strain ATCC 16883, a new strain, showed the zone of hydrolysis surrounding the fungal growth on the inulin medium plate. The action pattern of inulinase was determined by thin layer chromatography which confirmed it to be exoinulinase in nature. Solid state fermentation of A. flavus ATCC 16883 using Saccharum arundinaceum showed a maximum inulinase activity of 3.48U/gds after 96 h. The inulinase nature of the enzyme was confirmed by the resultant I/S ratio of 2.56. Central Composite Design (CCD) was used to optimize the media components and obtain a quadratic model using the five significant nutrients namely, inulin, K2HPO4, (NH4)2SO4, KH2PO4 and NaCl. Using the optimum conditions of (g/gds) inulin- 0.1, K2HPO4- 0.05, (NH4)2SO4- 0.002, KH2PO4- 0.005 and NaCl- 0.02, the inulinase activity was determined as 8.57U/gds which was 2.50-fold higher than the initial unoptimized conditions.

Characterization and anti-Aspergillus flavus impact of nanoparticles synthesized by Penicillium citrinum.

This work was conducted to evaluate the ability of grape molding fungus; Penicillium citrinum to synthesize silver nanoparticles (Ag NPs). The potency of biosynthesized Ag NPs was checked against the aflatoxigenic Aspergillus flavus var. columnaris, isolated from sorghum grains. Biosynthesized Ag NPs were characterized and confirmed in different ways. X ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM) and optical absorption measurements confirmed the bio-synthesis of Ag NPs. The in vitro antifungal investigation showed that biosynthesized Ag NPs were capable of inhibiting the growth of aflatoxigenic A. flavus var. columnaris. Utilization of plant pathogenic fungi in the Ag NPs biosynthesis as well as the use of bio-Ag NPs to control fungal plant diseases instead of chemicals is promising. Further work is needed to confirm the efficacy of the bio-Ag NPs against different mycotoxigenic fungi and to determine the potent applicable doses.

In vitro antimicrobial efficacy of Rhynchostegium vagans A. Jaeger (moss) against commonly occurring pathogenic microbes of Indian sub-tropics

ObjectiveTo study the antimicrobial effect of organic extracts with a standard dose of Rhynchostegium vagans (R. vagans) on pathogenic bacteria and fungi. MethodsR. vagans was extracted in solvents (ethanol and acetone) and the extracts were evaluated for antimicrobial activity by using disc diffusion assay. Minimum inhibitory concentration and minimum bactericidal/fungicidal concentration was observed by employing micro broth dilution method. Mode of inhibition of ethanolic extract against Aspergillus flavus var. columnaris (A. flavus var. columnaris) was assessed by scanning electron microscopy. ResultsIt was found that the ethanolic extract of R. vagans was the most potent with lowest minimum inhibitory concentration (3.91 to 61.25 μg/mL) and minimum bactericidal/fungicidal concentration (3.91 to 500 μg/mL), respectively. Significant morphological and ultrastructural alterations were seen in A. flavus var. columnaris. Among microorganisms, Gram negative bacteria (Escherichia coli, Erwinia chrysanthemi and Salmonella enterica) and fungi (A. flavus var. columnaris and Aspergillus parasiticus var. globosus) were found more sensitive. Ethanolic extract was found superior over the antibiotics (chloramphenicol and fluconazole). ConclusionsR. vagans exhibited effective antimicrobial activity against all the microorganisms. The moss can be used as a broad spectrum herbal antimicrobial agent in pharmaceutics.

Вплив іонів металів та специфічних хімічних реагентів на активність α-амілаз Aspergillus flavus var. Oryzae і Bacillus subtilis

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.

An Evaluation of Aflatoxin and Cyclopiazonic Acid Production in Aspergillus oryzae

To date, edible fungi such as Aspergillus flavus var. oryzae (A. oryzae) has been considered as safe. However, some strains can produce mycotoxins. Thus, the biosynthetic ability to produce mycotoxins should be reevaluated to determine the safety of edible fungi. We analyzed the production of aflatoxins and cyclopiazonic acid (CPA) from edible fungi such as A. oryzae isolated from various Korean foods using multiplex PCR, enzyme-linked immunosorbent assay, and high-performance liquid chromatography (HPLC). In the multiplex PCR analysis of aflatoxin biosynthetic genes omtB, aflR, ver-1, and omtA, 5 of 19 Aspergillus strains produced all PCR products. Among them, aflatoxin B1 and aflatoxin B2 were detected from only A. flavus KACC 41403 by HPLC. Aflatoxins were not detected from the other four strains that produced all positive PCR bands. Aflatoxin also was not detected from 12 strains that had PCR patterns without aflR or ver-1 and from 2 strains that did not produce any of the expected PCR products. Only the seven A. oryzae strains that produced all of the positive PCR bands including the CPA biosynthetic genes maoA, dmaT, and pks-nrps produced CPA. CPA and aflatoxin production must be evaluated before A. oryzae strains are used for the development of fermented foods.

Cellulose decomposing fungi and cellulase activity as affected by amistar and moncut fungicides

Spray application of the two fungicides; Amistar (25% Azoxystrobin) and Moncut (25% Flutolanil) on faba bean plants in the field exhibited an inhibitive effect on the total and individual counts of cellulose decomposing fungi associated with roots and shoots of plants. The inhibitive effect of these fungicides depended mainly on the fungicide concentration. The inhibitive effect was increased with the increase in fungicide concentration at different periods of treatment. Forty four fungal isolates representing 35 species and 2 varieties belonging to 19 genera were screened for their abilities to produce exo-β-1,4 glucanase and endo-β-1,4 glucanase enzymes. All fungal isolates tested had the ability to produce cellulase enzymes, but with variable degrees. For exo-β-1, 4 glucanase, six isolates (represent 13.7% of total isolates) showed high cellulase activity. However, twenty one isolates (47.7% of total isolates) were found to be moderate in their cellulase activity. The remaining isolates (17 isolates, represent 38.6% of total isolates) were low producers of cellulase. For endo-β-1, 4 glucanase enzyme, five isolates (represent 11.4% of total isolates) showed high cellulase activity and twenty one isolates (47.7% of total isolates) had moderate ability to produce cellulase. The remaining isolates (18 isolates, represent 40.9% of total isolates) were low producers of cellulase. When these fungicides (at 100-800 ppm) were incorporated individually into the liquid culture medium specified for growth and an extracellular cellulase production was exerted an inhibitive effect on both mycelial growth and cellulase production of Aspergillus flavus var. columnaris, A. fumigatus, A. ochraceous, Mucor hiemalis and Trichoderma harzianum. Key words: Fungicides, faba bean, cellulose decomposing fungi, cellulase enzymes.

Effect of amistar and moncut fungicides on fungi of faba bean plant and amylase activity

Amistar (Azoxystrobin 25%) and moncut (Flutolanil 25%) fungicides were used for treatment of faba bean plants in the field. Foliar application of the two fungicides by three doses exhibited a toxic effect on the total and individual fungal species associated with the roots and shoots of plant. The inhibitive effect of these fungicides depended mainly on the fungicide concentration. The inhibitive effect increased with increasing concentration of fungicide at different periods of treatment. The ability of different fungal isolates to produce amylase enzymes was tested. Among 44 fungal isolates screened for amylase production, 19 isolates (43.2% of total isolates) exhibited high amylase activity. However 16 isolates (36.4% of total isolates) exhibited moderate amylase activity whereas the remaining 9 isolates (20.4% of total isolates) were low producers of amylase. When the two fungicides individually incorporated into the culture medium for amylase production (at 100 to 800 ppm) an inhibitive effect was exerted on the fungal growth and amylase production of Aspergillus flavus var. columnaris, Aspergillus tamarii, Penicillium chrysogenum and Penicillium funiculosum. Key words: Fungicides, faba bean fungi, amylase enzymes.

Decolourisation of model and industrial dyes by mitosporic fungi in different culture conditions

Six mitosporic fungi belonging to five species (Aspergillus flavus var. flavus, Aspergillus ochraceus, Cladosporium cladosporioides, Penicillium glabrum and Penicillium verrucosum) were selected from a screening on 258 fungal strains as the most promising for their ability to remove 2 model dyes in solid conditions. Hence they were tested in liquid conditions for their ability to decolourise 3 model dyes and 9 industrial dyes widely used in the textile industry. The influence of the culture medium, particularly its carbon:nitrogen ratio, on biomass development and decolourisation capacity was considered. All the strains were able to grow in the dyed media and displayed various degrees of decolourisation according to the dye and culture medium. The decolourisation was due to biosorption phenomena. Aspergillus ochraceus performed the highest decolourisation yield being able to remove all dyes over 90%. This strain was also found very effective, both in the living and inactivated form, against simulated effluents that mimicked the recalcitrance of real wastewaters being composed of ten different dyes at high concentration (1,000 ppm), in saline solution.

AFLATOXINAS - ASPECTOS CLÍNICOS E TOXICOLÓGICOS EM SUÍNOS

Aflatoxinas são metabólitos fúngicos produzidos por linhagens de Aspergillus flavus var. parasiticus encontrados ubiquitariamente nos substratos alimentares que compõe a dieta dos suínos. A aflatoxicose dos suínos é uma doença dependente da dose ingerida e do tempo de exposição, caracterizando-se principalmente pela atividade hepatotóxica desta micotoxina. Na suinocultura os maiores problemas são provocados por doses subclínicas onde esta intoxicação se manifesta na forma de prejuízos sobre o desempenho traduzidos principalmente por uma baixa conversão alimentar e por imunodepressão.

Fungal flora and mycotoxins of six kinds of nut seeds for human consumption in Saudi Arabia

A wide range of moulds representing several genera and species, was recorded in this study from 5 seed samples of each almond, cashew nut, chestnut, hazelnut, pistachio nut and walnut collected from different markets in Ar' Ar, Saudi Arabia. The total counts of fungi were widely fluctuated between 1960-7704 and 1948-7434 colonies/g dry seeds on glucose-Czapek's and glycerol agar media at 28 degrees C, respectively, and represented twenty genera, 53 species and 2 varieties of fungi. The prevalent fungi on the 2 agar media were Aspergillus flavus, A. niger and Penicillium chrysogenum. On glucose-Czapek's agar, Rhizopus stolonifer and Aspergillus flavus var. columnaris were isolated from all 6 kinds of nut, A. parasiticus from 5 kinds and A. fumigatus from 4 kinds with high frequencies. Eurotium species were completely absent on glucose-Czapek's agar but they were isolated in high frequency from all kinds of nut on glycerol agar medium. The different nut samples were analyzed by thin layer chromatography for the presence of aflatoxins B1, B2, G1 & G2, citrinin, ochratoxins, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin and zearalenone. Aflatoxins B1 & G1 were detected in 3 out of the 5 samples tested of chestnut at concentrations ranging between 20 to 60 micrograms/kg. All other samples of almond, cashew nut, hazelnut, pistachio nut, and walnut that were analyzed were mycotoxin free.

Survival ofAspergillus flavusSclerotia and Conidia Buried in Soil in Illinois or Georgia

We examined the survival of sclerotia and conidia produced by Aspergillus flavus var. flavus and A. flavus var. parasiticus that were buried at a depth of 10-12 cm for up to 36 mo (October 1986 to October 1989) in sandy field soils near Kilbourne, Illinois, or Tifton, Georgia. Substantial losses of conidial inoculum were recorded after the first year of burial in Georgia and after the second year of burial in Illinois. Conidia of A. f. parasiticus survived for longer periods in soil than did conidia of A. f. flavus. Most sclerotia from eight A. flavus strains were viable at the conclusion of the experiment (Illinois, 77-99% viability; Georgia, 68-100% viability), as measured by colony growth of A. flavus on potato dextrose agar. None of these sclerotia, however, germinated sporogenically on sand in moist chambers. Production of large numbers of fungal propagules in the soil suggested that some of the sclerotia varied according to strain and location; numbers were maximum after the first growing season. Fungal colonization of A. flavus sclerotia buries in Georgia was dominated by Paecilomyces lilacinus; in Illinois the sclerotia were colonized most frequently by P. lilacinus and Periconia macrospinosa.

Paecilomyces Lilacinus, a Colonist of Aspergillus Flavus Sclerotia Buried in Soil in Illinois and Georgia

(1990). Paecilomyces Lilacinus, a Colonist of Aspergillus Flavus Sclerotia Buried in Soil in Illinois and Georgia. Mycologia: Vol. 82, No. 3, pp. 393-395.

Entomotoxigenic Potential of Wild and Domesticated Yellow-Green Aspergilli: Toxicity to Corn Earworm and Fall Armyworm Larvae

Corn earworm (Heliothis zea) and fall armyworm (Spodoptera frugiperda) larvae were fed on diets consisting of maize kernels fermented (8 da; 28 C) with individual strains of “wild” or domesticated yellow-green aspergini (e.g., wild isolates = Aspergillus flavus var. flavus, A. flavus var. parasiticus; domesticated, non-aflatoxigenic koji molds = A. flavus var. oryzae, A. flavus var. sojae). Kernels fermented with individual strains of var. sojae were less toxic to larvae than kernels fermented with isolates of the related wild variety parasiticus. Likewise, kernels fermented with isolates of var. flavus were, with one exception (NRRL 6513), more toxic to fall armyworm larvae than kernels fermented with isolates of the related domesticated variety oryzae. As a group, strains of var. oryzae were no less toxic to corn earworm larvae than the var. flavus strains that were tested. Toxic fungal metabolities are believed to be the direct cause of larval mortality because dead larvae were not colonized by fungal hyphae. This is consistent with the hypothesis that wild strains of A. flavus produce a suite of defensive entomotoxic metabolites having no adaptive value in a koji environment. We suggest that koji molds used in food fermentations be screened by means of insect bioassays as a relevant test of the toxigenic potential of individual domesticated strains.

Entomotoxigenic Potential of Wild and Domesticated Yellow-Green Aspergilli: Toxicity to Corn Earworm and Fall Armyworm Larvae

Corn earworm (Heliothis zea) and fall armyworm (Spodoptera frugiperda) larvae were fed on diets consisting of maize kernels fermented (8 da; 28 C) with individual strains of or domesticated yellow-green aspergilli (e.g., wild isolates = Aspergillus flavus var. flavus, A. flavus var. parasiticus; domesticated, non-aflatoxigenic koji molds = A. flavus var. oryzae, A. flavus var. sojae). Kernels fermented with individual strains of var. sojae were less toxic to larvae than kernels fermented with isolates of the related wild variety parasiticus. Likewise, kernels fermented with isolates of var. flavus were, with one exception (NRRL 6513), more toxic to fall armyworm larvae than kernels fermented with isolates of the related domesticated variety oryzae. As a group, strains of var. oryzae were no less toxic to corn earworm larvae than the var. flavus strains that were tested. Toxic fungal metabolities are believed to be the direct cause of larval mortality because dead larvae were not colonized by fungal hyphae. This is consistent with the hypothesis that wild strains ofA. flavus produce a suite of defensive entomotoxic metabolites having no adaptive value in a koji environment. We suggest that koji molds used in food fermentations be screened by means of insect bioassays as a relevant test of the toxigenic potential of individual domesticated strains.

Effect of chemicals on fungal α-amylase activity

The effect of 8 growth regulators at concentrations of 1,000, 5,000 and 10,000 ppm on the activity of fungal (Aspergillus flavus var. columnaris) alpha-amylase was studied. Indol acetic acid (IAA) and naphthalene acetic acid (NAA) inhibited alpha-amylase activity by 2% and 7% at 1,000 ppm. The other 6 growth regulators, indol butyric acid (IBA), gibberellic acid, cumarin, cycocel (CCC), atonik-G and kylar, did not inhibit but stimulated alpha-amylase activity (0 to 9%) at 1,000 ppm. All growth regulators studied inhibited alpha-amylase activity at 5,000 and 10,000 ppm concentration except kylar. The effect of organic acids and formaldehyde at 0.01, 0.005, and 0.001 M was studied. Acetic acid stimulated alpha-amylase at all concentrations, but formic acid, oxalic acid, lactic acid and citric acid inhibited alpha-amylase activity by 91, 100, 100 and 79%, respectively, at a concentration of 0.01 M, while by 31, 100, 15 and 20%, respectively, at 0.005 M. Formaldehyde induced 7, 3 and 2% inhibition at 0.01, 0.005 and 0.001 M, respectively. At 0.01 M either sorbitol or fructose inhibited alpha-amylase by 8%, Maltose 7%, sucrose 6%, phenol, glucose and galactose each by 5%, ethanol, glycerol, arabinose and sodium benzoate each by 4%, isopropanol and mannitol 1%, but methanol and ammonium citrate dibasic did not inhibit alpha-amylase. The results indicate that CuCl2, SnCl2, AgNO3 and Fe2(SO4)3 were the strongest inhibitors, followed by Cd(C2H3O2), HgCl2, Na2-EDTA, Na2HPO4, and CaCl2 in decreasing order. NaCl, NaBr and Mn SO4 did not inhibit alpha-amylase at concentrations from 10 mM to 0.01 mM.

Radiosensitivity of toxigenic Aspergillus isolated from spices and destruction of aflatoxins by gamma-irradiation

Radiosensitivities of Aspergillus flavus var columnaris isolated from spices were investigated. The D 10 values and induction doses were 267–293 Gy and 75–165 Gy in wet conditions, respectively. In dry conditions, the survival curves were exponential and D 10 values were 538–600 Gy. The survival curves of standard strain of A. parasiticus IFO 30179 were similar both in wet and dry conditions. The necessary dose of 8 kGy for the destruction of these toxigenic Aspergillus was calculated from these values. Two of 11 strains of A. flavus var columnaris produced aflatoxins and the content of B 1 was especially high. In the study of irradiation effect on aflatoxins produced on polished rice, aflatoxins G 1 and B 1 were more radiosensitive than G 2 and B 2. However, these aflatoxins were very stable to radiation and the dose required for destruction was found to be more than 500 kGy. It is therfore concluded that the decontamination of molds by irradiation is necessary prior to their production of aflatoxins.

Occurrence of toxicity among protease, amylase, and color mutants of a nontoxic soy sauce koji mold

A soy sauce koji mold, Aspergillus flavus var. columnaris Raper and Fennel (ATCC 44310), was treated with UV irradiation to obtain mutant strains possessing high protease activities, high amylase activities, and light-colored conidia. Selected mutant strains were tested for toxicity, and some were found acutely toxic to weanling rats, although all were negative for aflatoxin production.

Effect of Aspergillus flavus mycotoxin on Culex mosquito larvae

An isolate of Aspergillus flavus var. columnaris recovered from moribund larvae of the mosquito Culex peus produced metabolites which caused mortality in larvae of C. peus and C. tarsalis. Production of these toxins in vitro on solid substrate rice was based on culture techniques used in making Ang kak. The effect of incubation time on mycotoxin production was determined for cultures fermented from 3 to 13 days. Mycotoxins produced by isolate FU-051 were extracted by refluxing the spent medium with chloroform. Fractionation on a silicic acid column with a methanol-chloroform (3:97 v v ) solvent mixture yielded two toxic fractions. Toxic activity was determined using a biological assay with mosquito larvae.