Comparison of the rodlet layer proteins of Aspergillus flavus and Aspergillus fumiguatus
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap Velos
ORGANISM(S): Aspergillus Fumigatus Af293 Aspergillus Flavus Frr 342
SUBMITTER: 
Jeya Maheshwari Jayapal
LAB HEAD: K. Dharmalingam
PROVIDER: PXD020592 | Pride | 2021-09-09
REPOSITORIES: Pride
Publications
Species-Specific Immunological Reactivities Depend on the Cell-Wall Organization of the Two <i>Aspergillus</i>, <i>Aspergillus fumigatus</i> and <i>A. flavus</i>.
Wong Sarah Sze Wah SSW Venugopalan Lakshmi Prabha LP Beaussart Audrey A Karnam Anupama A Mohammed Mohammed Razeeth Shait MRS Jayapal Jeya Maheshwari JM Bretagne Stéphane S Bayry Jagadeesh J Prajna Lalitha L Kuppamuthu Dharmalingam D Latgé Jean-Paul JP Aimanianda Vishukumar V
Frontiers in cellular and infection microbiology 20210225
Although belong to the same genus, <i>Aspergillus fumigatus</i> is primarily involved in invasive pulmonary infection, whereas <i>Aspergillus flavus</i> is a common cause of superficial infection. In this study, we compared conidia (the infective propagules) of these two <i>Aspergillus</i> species. In immunocompetent mice, intranasal inoculation with conidia of <i>A. flavus</i> resulted in significantly higher inflammatory responses in the lungs compared to mice inoculated with <i>A. fumigatus</ ...[more]
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Project description: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 understand host response to infection by the fungus, transcription of approximately 9,000 maize genes were monitored during the host-pathogen interaction with a custom-designed Affymetrix GeneChip® DNA array. More than 1,000 maize genes were found differentially expressed at a fold change of 2 or greater. 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 A. flavus induced metabolic changes in the kernel, including the production of a defense response, as well as a disruption in kernel development. Maize kernels were mock inoculated at the blister (R2) or dough (R4) stage or inoculated with A. flavus at the blister (R2), milk (R3), dough (R4), or dent (R5) stage, and harvested 4 days later. Each treatment consisted of three biological replications. For each biological replication, 8 kernels were ground and RNA was isolated and further processed.
2014-05-14 | E-GEOD-57629 | biostudies-arrayexpress
Project description:Aspergillus flavus is a common saprophyte and opportunistic pathogen producing aflatoxin (AF) and many other secondary metabolites. 5-Azacytidine (5-AC), a derivative of nucleoside cytidine, is widely used for studies in epigenetics and cancer biology as an inactivator of DNA methyltransferase and is also used for studying secondary metabolism in fungi. Our previous studies showed that 5-AC affects development and inhibits AF production in A. flavus, and that A. flavus lacks DNA methylation. How this common DNA methyltransferase inhibitor affects development and AF production is not clear. In this study, we applied an RNA-Seq approach to elucidate the mechanism of 5-ACM-bM-^@M-^Ys effect on A. flavus. In our current study, we identified 240 significantly differently expressed (Q-value<0.05) genes after 5-AC treatment, including two backbone genes in secondary metabolite clusters #27 and #35, which are involved in development or survival of sclerotia. With 5-AC treatment, about three quarters of the genes in the AF biosynthetic gene cluster in A. flavus were down-regulated to a certain degree. Strikingly, at least two genes aflI and aflLa, were completely inhibited. Interestingly, several genes involved in fungal development were down-regulated, especially veA, which is a gene that encodes protein bridges VelB and LaeA. This result supports the hypothesis that 5-AC affects development and AF production through weakening or even interrupting the connection between VelB and LaeA and then causing dysregulation of the expression pattern of genes involved in development and secondary metabolism. Our results improved the A. flavus genome annotation, provided a comprehensive view of the transcriptome of A. flavus responding to 5-AC and confirmed that fungal development and secondary metabolism are co-regulated. In additon, the RNA-Seq data of another sample treated with gallic acid was used to improve A. flavus genome annotation. mRNA of Aspergillus flavus cultured in three different culture media PDB, PDB+5-AC(5-Azacytidine),and PDB+GA(gallic acid) was subjected to sequence independently.
2013-06-15 | E-GEOD-40202 | biostudies-arrayexpress
Project description:The molecular mechanisms underlying aflatoxin production have been well-studied in strains of the fungus Aspergillus flavus (A. flavus) under artificial conditions. However, aflatoxin biosynthesis has rarely been studied in natural isolates of A. flavus strains. In the present study, tandem mass tag (TMT) labeling and high-performance liquid chromatography (HPLC) coupled with tandem-mass spectrometry analysiswere used for proteomic quantification in natural isolates of high- and low-aflatoxin-yield A. flavus strains.
2022-02-17 | PXD027517 | Pride
Project description:Aspergillus flavus first gained scientific attention for its production of aflatoxin, the most potent naturally occurring toxin and hepatocarcinogenic secondary metabolite. For several decades, The DNA methylation status of A. flavus remains to be controversial. We first applied bisulfite sequencing, the gold standard at present, in conjunction with a biological replicate strategy to investigate the DNA methylation profiling of A. flavus genome. Our results reveal that the DNA methylation level of this fungus turns out to be negligible, comparable to the unmethylated lambda DNA we set as the false positive control of our bisulfite experiments. When comparing the DNA methyltransferase homolog of A. flauvs with that from several selected hypermethylated speices, we find that the DNA methyltransferase homolog of A.flavus as well as the other Aspergillus members groups closely with the RID from Neurospora crassa and Masc1 from Ascobolus immerses, which has been reported as DMT-incapable, but it diverges distantly from the other capable DNA methyltransferases. We observe significant depletion of repeat components within the A. flavus, which may possibly explain the lack of DNA methylation in this fungus. What's more, the RIP-index of the repeat of A. flavus turns out to be higher than the fungi without RID-like enzyme, suggesting this asexual fungus may possibly possess RIP process during the obscure sexual-stage which is very evanescent and may potentially related to DNA methylation. This work contributes to our understanding on the DNA methylation status of A. flavus. Also, it reinforces our views on the DNA methylation in fungal species. What's more, our strategy of applying bisulfite sequencing to DNA methylation detection on species with low DNA methylation may serve as a reference for later scientific investigations on other hypomethylated species. Two replicates were subjected to bisulfite conversion independently, unmethylated lambda DNA as a false positive control is added to both replicates.
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2022-06-06 | PXD030912 | Pride
Project description:Aflatoxin contamination caused by the opportunistic pathogen A. flavus is a major concern in maize production prior to harvest and during storage. Previous studies indicate that both constitutive and induced resistance are involved in maize kernel defense against A. flavus infection, little is known about molecular mechanisms of mature kernels in response to fungal infection. The purpose of this study is to determine gene expression differences in maize kernels between resistant and susceptible lines in response to A. flavus challenge. To avoid the environmental effects in the field inoculation, a laboratory based inoculation technique Kernel Screening Assay (KSA) was used to challenge kernels with A. flavus. After 72 hours incubation of inoculated and noninculated mature kernels, gene expression profiles of two Near Isogenic Lines (NIL) of Eyl25 (A. flavus resistant) and Eyl31 (A. flavus susceptible) were compared using oligonucleotide array. Direct comparisons were designed. The comparisons of NIL Eyl25 and Eyl31 include: Treated/Control, Control/Control and Treated/Treated. After 72 hours incubation under KSA conditions, forty seeds used in each A. flavus inoculated and noninculated group were bulked to extract total RNA. Four technical replications were performed in each comparison including two dye-swaps, total 16 hybridization reactions.
2010-10-01 | E-GEOD-19883 | biostudies-arrayexpress
Project description:Several are the inputs which are able to modulate mycotoxin synthesis. In particular, when a fungus receives an external stimulus reacts by activating, through a quite well-defined signal cascade, an evident switch in its lifestyle. This profound change is also due to the activation of global gene regulators and, in particular, of transcription factors able to switch on the mycotoxin gene clusters expression. Aflatoxins (AF) are harmful carcinogenic compounds produced mainly by Aspergillus flavus and A. parasiticus. AF are produced during the contamination of maize kernels into the field, even if their role in phyto-toxicity is not yet assessed. Nevertheless, AF biosynthesis is tightly regulated by host-derived signals. Recently, the nature of some of these signals have been elucidated. In particular, a role in susceptibility and resistance of maize to A. flavus contamination has been assigned to some plant oxylipins. These findings draw a scenario in which a complex interplay is under way between A. flavus and maize. For uncovering all the implications of this cross-talk we decide to follow a holistic approach. In particular, we designed experimental conditions aimed to mimic the different phases of A. flavus infection cycle on maize and then by performing a microarray analysis on the harvested mycelia. The microarray data set has been processed for performing the differential expression analysis of almost 14000 gene probes, the pathway analysis based on the gene ontology and inter pro annotations, the secondary metabolites cluster co-expression analysis and an identification of groups of co-expressed neighbor genes, possibly associated with production of secondary metabolites. Analysis of 12 microarrays monitoring gene expression of Aspergillus flavus over various growth conditions
2013-09-19 | E-GEOD-28163 | biostudies-arrayexpress
Project description:Naturally occurring Antisense Transcripts (NATs) compose an emerging group of regulatory RNAs. These regulatory elements appear in all organisms examined, but little is known about global expression of NATs in fungi. Analysis of currently available EST sequences suggests that 352 cis NATs are present in Aspergillus flavus. An Affymetrix GeneChip® microarray containing probes for these cis NATs, as well as all predicted genes in A. flavus, allowed a whole genome expression analysis of these elements in response to two ecologically important temperatures for the fungus. RNA expression analysis showed that 32 NATs and 2709 genes were differentially expressed between 37°C, the optimum temperature for growth, and 28°C, the conducive temperature for the biosynthesis of aflatoxin (AF) and many other secondary metabolites. These NATs correspond to sense genes with diverse functions including transcription initiation, carbohydrate processing and binding, temperature sensitive morphogenesis, and secondary metabolism. This is the first report of a whole genome transcriptional analysis of NAT expression in a fungus and shows that although less than 10% of putative NATs are differentially expressed in response to temperature, some of the NAT-cis gene interactions are likely to be important. Keywords: temperature response 3 samples (reps) for each temperature treatment were analyzed with a total of 6 samples.
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Project description:Aspergillus flavus is one of the major fungal molds that colonize peanut in the field and during storage. The impact to human and animal health and to economy in agriculture and commerce are significant since this mold produces the most potent 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 to inhibit aflatoxin formation through down-regulating aflatoxin pathway gene expression in A. flavus as demonstrated by genechip analysis in liquid medium and peanuts. The results showed that aflatoxin accumulation in potato dextrose broth liquid medium and liquid minimal medium was almost totally (more than 98%) inhibited by B. megaterium. The expression of many of the aflatoxin biosynthetic genes in the fungus was confirmed to be turned down. Some of the target genes down-regulated by B. megaterium within the whole genome and within the aflatoxin pathway gene cluster (aflF, aflT, aflS, aflJ, aflL, aflX) were identified. These target 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 found to be significantly down-regulated. The effect of B. megaterium on aflatoxin biosynthesis and genes expression of pathogen was firstly tested in potato dextrose broth (PDB) and glucose minimal salts medium (MM). The cell suspension of B. megaterium (concentration in PDB and MM was finally adjusted to 108 CFU/ml) or sterile distilled water as a control was added into the 100 ml beaker flask containing 15 ml PDB or MM, respectively. Then 100 M-NM-<l of spore suspension (5 M-CM-^W 106 spores/ml) of A. flavus were added into each beaker flask. After 48 h of incubation at 28M-BM-0C at 200 rpm, mycelia were collected, fresh frozen with liquid nitrogen, ground to a fine powder in liquid nitrogen, and stored at -80M-BM-0C for further analysis. The effect of B. megaterium on aflatoxin biosynthesis and genes expression in the A. flavus fungal pathogen was also tested in two types of peanut kernels, UF 715133-1 and Jinhua 1012, respectively. Peanut kernels were wounded (6 mm diameter and approximately 3 mm deep) using a sterile borer and then 20 M-NM-<l of 1 M-CM-^W 108 CFU/ml cell suspension of B. megaterium was inoculated on wounded peanut kernels respectively. Sterile distilled water was also used for inoculation as control. Two hours after bacterial inoculation, 10 M-NM-<l A. flavus spore suspension was inoculated into each wound at a concentration of 106 spores/ml. The kernels were placed in artificial weather chamber to maintain high humidity (85%) and incubated at 28M-BM-0C for 7 days. Each treatment was replicated three times with 20 peanut kernels in each test. The mycelia on kernels were harvested at day 7 and fresh frozen immediately in liquid nitrogen, ground into powder, and stored at -80M-BM-0C for further analysis.
2013-10-22 | E-GEOD-51469 | biostudies-arrayexpress
Project description:To better understand the effect of temperature on mycotoxin biosynthesis, RNA-Seq technology was used to profile the Aspergillus flavus transcriptome under different temperature conditions. This approachallowed us to quantify transcript abundance for over 80% of fungal genes including 1,153 genes that were differentially expressed at 30M-BM-0C and 37M-BM-0C. Wleven of the 55 secondary metabolite clusters were up-regulated at the lower temperature, including aflatoxin biosynthesis genes, which were among the most highly up-expressed genes. On average, transcript abundance for the 30 aflatoxin biosynthesis genes was 3,300 times greater at 30M-BM-0C as compared to 37M-BM-0C. The results are consistent with the view that high temperature negatively affects aflatoxin production by turning down transcription of the two key transcriptional regulators, aflR and aflS. Subtle changes in the expression levels of aflS to aflR appear to control transcription activation of the aflatoxin cluster. 2 samples examined: from the fungus grown at 30M-BM-0C and 37M-BM-0C
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