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Journal of Agricultural and Food... May 2024contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination....
contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (H and C NMR). Then, the efficiency of BAC against ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of . Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.
Topics: Aspergillus flavus; Benzimidazoles; Chitosan; Fungicides, Industrial; Microbial Sensitivity Tests; Aflatoxins; Antifungal Agents; Spores, Fungal
PubMed: 38687832
DOI: 10.1021/acs.jafc.4c01010 -
Investigative Ophthalmology & Visual... Apr 2024Fungal endophthalmitis is characterized by chronic inflammation leading to the partial or complete vision loss. Herein, we analyzed the transcriptomic landscape of...
PURPOSE
Fungal endophthalmitis is characterized by chronic inflammation leading to the partial or complete vision loss. Herein, we analyzed the transcriptomic landscape of Aspergillus flavus (A. flavus) endophthalmitis in C57BL/6 mice to understand the host-pathogen interactions.
METHODS
Endophthalmitis was induced by intravitreal injection of A. flavus spores in C57BL/6 mice and monitored for disease progression up to 72 hours. The enucleated eyeballs were subjected to histopathological analysis and mRNA sequencing using the Illumina Nextseq 2000. Pathway enrichment analysis was performed to further annotate the functions of differentially expressed genes (DEGs) and validation of cytokines was performed in vitreous of patients with fungal endophthalmitis using multiplex ELISA.
RESULTS
Transcriptomic landscape of A. flavus endophthalmitis revealed upregulated T-cell receptor signaling, PI3K-AKT, MAPK, NF-κB, JAK-STAT, and NOD like receptor signaling pathways. We observed significant increase in the T-cells during infection especially at 72 hours infection along with elevated expression levels of IL-6, IL-10, IL-12, IL-18, IL-19, IL-23, CCR3, and CCR7. Furthermore, host-immune response associated genes, such as T-cell interacting activating receptor, TNF receptor-associated factor 1, TLR1, TLR9, and bradykinin receptor beta 1, were enriched. Histopathological assessment validated the significant increase in inflammatory cells, especially T-cells at 72 hours post-infection along with increased disruption in the retinal architecture. Additionally, IL-6, IL-8, IL-17, TNF-α, and IL-1β were also significantly elevated, whereas IL-10 was downregulated in vitreous of patients with Aspergillus endophthalmitis.
CONCLUSIONS
Regulating T-cell influx could be a potential strategy to modulate the excessive inflammation in the retina and potentially aid in better vision recovery in fungal endophthalmitis.
Topics: Animals; Aspergillus flavus; Mice; Mice, Inbred C57BL; Disease Models, Animal; Eye Infections, Fungal; Endophthalmitis; Aspergillosis; Adaptive Immunity; Immunity, Innate; Gene Expression Profiling; Cytokines; Transcriptome; Enzyme-Linked Immunosorbent Assay; Vitreous Body
PubMed: 38687493
DOI: 10.1167/iovs.65.4.44 -
Pesticide Biochemistry and Physiology May 2024Aspergillus flavus is a ubiquitous facultative pathogen that routinely infects important crops leading to formation of aflatoxins during crop development and after...
Aspergillus flavus is a ubiquitous facultative pathogen that routinely infects important crops leading to formation of aflatoxins during crop development and after harvest. Corn and peanuts in warm and/or drought-prone regions are highly susceptible to aflatoxin contamination. Controlling aflatoxin using atoxigenic A. flavus is a widely adopted strategy. However, no A. flavus genotypes are currently approved for use in China. The current study aimed to select atoxigenic A. flavus endemic to Guangxi Zhuang Autonomous Region with potential as active ingredients of aflatoxin biocontrol products. A total of 204 A. flavus isolates from corn, peanuts, and field soil were evaluated for ability to produce the targeted mycotoxins. Overall, 57.3% could not produce aflatoxins while 17.15% were incapable of producing both aflatoxins and CPA. Atoxigenic germplasm endemic to Guangxi was highly diverse, yielding 8 different gene deletion patterns in the aflatoxin and CPA biosynthesis gene clusters ranging from no deletion to deletion of both clusters. Inoculation of corn and peanuts with both an aflatoxin producer and selected atoxigenic genotypes showed significant reduction (74 to 99%) in aflatoxin B (AFB) formation compared with inoculation with the aflatoxin producer alone. Atoxigenic genotypes also efficiently degraded AFB (61%). Furthermore, atoxigenic isolates were also highly efficient at reducing aflatoxin concentrations even when present at lower concentrations than aflatoxin producers. The use of multiple atoxigenics was not always as effective as the use of a single atoxigenic. Effective atoxigenic genotypes of A. flavus with known mechanisms of atoxigenicity are demonstrated to be endemic to Southern China. These A. flavus may be utilized as active ingredients of biocontrol products without concern for detrimental impacts that may result from introduction of exotic fungi. Field efficacy trials in the agroecosystems of Southern China are needed to determine the extent to which such products may allow the production of safer food and feed.
Topics: Aspergillus flavus; Arachis; Zea mays; China; Aflatoxins; Biological Control Agents; Food Contamination; Genotype
PubMed: 38685218
DOI: 10.1016/j.pestbp.2024.105887 -
The Malaysian Journal of Pathology Apr 2024Invasive aspergillosis is the second most common invasive human mycosis but susceptibility data of Aspergillus species is limited. Antifungal treatment of aspergillosis...
Invasive aspergillosis is the second most common invasive human mycosis but susceptibility data of Aspergillus species is limited. Antifungal treatment of aspergillosis is often done empirically without knowing the true susceptibility. Therefore, we aimed to determine antifungal susceptibility of Aspergillus species isolated from various clinical specimens over a 1-year period. We identified 28 Aspergillus isolates by sequencing the internal transcribed spacer (ITS) and β-tubulin genes and performed antifungal susceptibility testing on these isolates using Sensititre YeastOne. The isolates were identified as Aspergillus niger (60.7%), A. fumigatus (21.4%), A. flavus (10.7%), A. chevalieri (3.6%) and A. tubingensis (3.6%). Based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) Antifungal Clinical Breakpoint for Aspergillus spp., 16/17 (94.1%) A. niger isolates were susceptible to amphotericin B, all six isolates (100%) of A. fumigatus were susceptible to amphotericin B, itraconazole and voriconazole, but only 5/6 (83.3%) A. fumigatus were susceptible to posaconazole. Meanwhile, all three (100%) A. flavus isolates were susceptible to itraconazole. There are no other breakpoints established by the EUCAST for other antifungal-species combinations. In conclusions, Aspergillus niger remains the most commonly isolated species from clinical specimens and Aspergillus isolates at our centre are still largely susceptible to amphotericin B, echinocandins and most azoles. This information is valuable in guiding antifungal therapy in the treatment of aspergillosis.
Topics: Humans; Antifungal Agents; Aspergillus; Microbial Sensitivity Tests; Aspergillosis; Female; Male; Adult; Middle Aged; Aged
PubMed: 38682846
DOI: No ID Found -
Journal of Hazardous Materials Jun 2024Nitric oxide (NO) is a signaling molecule with diverse roles in various organisms. However, its role in the opportunistic pathogen Aspergillus flavus remains unclear....
Nitric oxide (NO) is a signaling molecule with diverse roles in various organisms. However, its role in the opportunistic pathogen Aspergillus flavus remains unclear. This study investigates the potential of NO, mediated by metabolites from A. oryzae (AO), as an antifungal strategy against A. flavus. We demonstrated that AO metabolites effectively suppressed A. flavus asexual development, a critical stage in its lifecycle. Transcriptomic analysis revealed that AO metabolites induced NO synthesis genes, leading to increased intracellular NO levels. Reducing intracellular NO content rescued A. flavus spores from germination inhibition caused by AO metabolites. Furthermore, exogenous NO treatment and dysfunction of flavohemoglobin Fhb1, a key NO detoxification enzyme, significantly impaired A. flavus asexual development. RNA-sequencing and metabolomic analyses revealed significant metabolic disruptions within tricarboxylic acid (TCA) cycle upon AO treatment. NO treatment significantly reduced mitochondrial membrane potential (Δψm) and ATP generation. Additionally, aberrant metabolic flux within the TCA cycle was observed upon NO treatment. Further analysis revealed that NO induced S-nitrosylation of five key TCA cycle enzymes. Genetic analysis demonstrated that the S-nitrosylated Aconitase Acon and one subunit of succinate dehydrogenase Sdh2 played crucial roles in A. flavus development by regulating ATP production. This study highlights the potential of NO as a novel antifungal strategy to control A. flavus by compromising its mitochondrial function and energy metabolism.
Topics: Citric Acid Cycle; Aspergillus flavus; Nitric Oxide; Mitochondria; Antifungal Agents; Membrane Potential, Mitochondrial; Spores, Fungal; Fungal Proteins
PubMed: 38678711
DOI: 10.1016/j.jhazmat.2024.134385 -
Molecules (Basel, Switzerland) Apr 2024Wall. Ex Besser is a folklore medicinal plant that belongs to Asteraceae family and a treasure trove of drugs. The aim of this research study was to investigate the...
Wall. Ex Besser is a folklore medicinal plant that belongs to Asteraceae family and a treasure trove of drugs. The aim of this research study was to investigate the phytoconstituents, antimicrobial activity, antioxidant, anti-inflammatory, cytotoxicity and wound healing potential of leaf extract (ALE). Phytochemical analysis of the ALE was carried out by Soxhlet extraction and GCMS (gas chromatography-mass spectrometry) analysis. Antimicrobial activity was performed by the agar well diffusion method against selected bacterial and fungal strains. Free radical scavenging potential was evaluated by DPPH (2,2-Diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (Ferric reducing antioxidant power) assays. Anti-inflammatory activity was performed by enzyme inhibition assay-COXII. The cytotoxicity of ALE on HaCaT cells was studied via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. An in vitro scratch assay was performed for the evaluation of the wound healing property of ALE. It showed satisfactory antimicrobial activity against (14.2 ± 0.28 mm), (17.6 ± 0.52 mm), (13.1 ± 0.37 mm), (17.3 ± 0.64 mm), (9.4 ± 0.56 mm), (12.7 ± 0.53 mm), (15.3 ± 0.25 mm) and (17.6 ± 0.11 mm). In ALE, 36 phytochemicals were detected by GCMS analysis, but 22 were dominant. Moreover, the ALE was effective in scavenging free radicals with different assays and exhibited reasonable anti-inflammatory activity. The MTT assay revealed that ALE had a cytotoxic effect on the HaCaT cells. The scratch assay showed 94.6% wound closure (after 24 h incubation) compared to the positive control Cipladine, which is remarkable wound healing activity. This is the first report on the wound healing property of , which can serve as a potential agent for wound healing and extends knowledge on its therapeutic potential.
Topics: Artemisia; Plant Extracts; Plant Leaves; Humans; Antioxidants; Phytochemicals; Anti-Infective Agents; Microbial Sensitivity Tests; Anti-Inflammatory Agents; Wound Healing; Candida albicans; HaCaT Cells; Gas Chromatography-Mass Spectrometry; Anti-Bacterial Agents; Cell Survival; Biphenyl Compounds; Picrates
PubMed: 38675649
DOI: 10.3390/molecules29081829 -
Toxins Apr 2024Velvet (VeA), a light-regulated protein that shuttles between the cytoplasm and the nucleus, serves as a key global regulator of secondary metabolism in various species...
Velvet (VeA), a light-regulated protein that shuttles between the cytoplasm and the nucleus, serves as a key global regulator of secondary metabolism in various species and plays a pivotal role in controlling multiple developmental processes. The gene was chosen for further investigation through CHIP-seq analysis due to significant alterations in its interaction with VeA under varying conditions. This gene (AFLA_006970) contains a Septin-type guanine nucleotide-binding (G) domain, which has not been previously reported in (). The functional role of in was elucidated through the creation of a gene knockout mutant and a gene overexpression strain using a well-established dual-crossover recombinational technique. A comparison between the wild type (WT) and the Δ mutant revealed distinct differences in morphology, reproductive capacity, colonization efficiency, and aflatoxin production. The mutant displayed reduced growth rate; dispersion of conidial heads; impaired cell wall integrity; and decreased sclerotia formation, colonization capacity, and aflatoxin levels. Notably, Δ exhibited complete growth inhibition under specific stress conditions, highlighting the essential role of in . This study provides evidence that positively influences aflatoxin production, morphological development, and pathogenicity in .
Topics: Aspergillus flavus; Aflatoxins; Fungal Proteins; Gene Expression Regulation, Fungal; Virulence; Spores, Fungal
PubMed: 38668599
DOI: 10.3390/toxins16040174 -
BMC Microbiology Apr 2024Kojic acid is a wonderful fungal secondary metabolite that has several applications in the food, medical, and agriculture sectors. Many human diseases become resistant...
Production of kojic acid by Aspergillus flavus OL314748 using box-Behnken statistical design and its antibacterial and anticancer applications using molecular docking technique.
Kojic acid is a wonderful fungal secondary metabolite that has several applications in the food, medical, and agriculture sectors. Many human diseases become resistant to normal antibiotics and normal treatments. We need to search for alternative treatment sources and understand their mode of action. Aspergillus flavus ASU45 (OL314748) was isolated from the caraway rhizosphere as a non-aflatoxin producer and identified genetically using 18S rRNA gene sequencing. After applying the Box-Behnken statistical design to maximize KA production, the production raised from 39.96 to 81.59 g/l utilizing (g/l) glucose 150, yeast extract 5, KHPO 1, MgSO.7HO 2, and medium pH 3 with a coefficient (R) of 98.45%. Extracted KA was characterized using FTIR, XRD, and a scanning electron microscope. Crystalized KA was an effective antibacterial agent against six human pathogenic bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Serratia marcescens, and Serratia plymuthica). KA achieves high inhibition activity against Bacillus cereus, K. pneumonia, and S. plymuthica at 100 μg/ml concentration by 2.75, 2.85, and 2.85 compared with chloramphenicol which gives inhibition zones 1, 1.1, and 1.6, respectively. Crystalized KA had anticancer activity versus three types of cancer cell lines (Mcf-7, HepG2, and Huh7) and demonstrated high cytotoxic capabilities on HepG-2 cells that propose strong antitumor potent of KA versus hepatocellular carcinoma. The antibacterial and anticancer modes of action were illustrated using the molecular docking technique. Crystalized kojic acid from a biological source represented a promising microbial metabolite that could be utilized as an alternative antibacterial and anticancer agent effectively.
Topics: Aspergillus flavus; Pyrones; Anti-Bacterial Agents; Humans; Molecular Docking Simulation; Antineoplastic Agents; Microbial Sensitivity Tests; Cell Line, Tumor; Bacteria
PubMed: 38658810
DOI: 10.1186/s12866-024-03289-2 -
International Journal of Food... Jun 2024Aspergillus flavus is a fungus notorious for contaminating food and feed with aflatoxins. As a saprophytic fungus, it secretes large amounts of enzymes to access...
Aspergillus flavus is a fungus notorious for contaminating food and feed with aflatoxins. As a saprophytic fungus, it secretes large amounts of enzymes to access nutrients, making endoplasmic reticulum (ER) homeostasis important for protein folding and secretion. The role of HacA, a key transcription factor in the unfolded protein response pathway, remains poorly understood in A. flavus. In this study, the hacA gene in A. flavus was knockout. Results showed that the absence of hacA led to a decreased pathogenicity of the strain, as it failed to colonize intact maize kernels. This may be due to retarded vegetable growth, especially the abnormal development of swollen tips and shorter hyphal septa. Deletion of hacA also hindered conidiogenesis and sclerotial development. Notably, the mutant strain failed to produce aflatoxin B1. Moreover, compared to the wild type, the mutant strain showed increased sensitivity to ER stress inducer such as Dithiothreitol (DTT), and heat stress. It also displayed heightened sensitivity to other environmental stresses, including cell wall, osmotic, and pH stresses. Further transcriptomic analysis revealed the involvement of the hacA in numerous biological processes, including filamentous growth, asexual reproduction, mycotoxin biosynthetic process, signal transduction, budding cell apical bud growth, invasive filamentous growth, response to stimulus, and so on. Taken together, HacA plays a vital role in fungal development, pathogenicity and aflatoxins biosynthesis. This highlights the potential of targeting hacA as a novel approach for early prevention of A. flavus contamination.
Topics: Aspergillus flavus; Fungal Proteins; Unfolded Protein Response; Aflatoxins; Transcription Factors; Gene Expression Regulation, Fungal; Zea mays; Virulence; Aflatoxin B1; Endoplasmic Reticulum Stress
PubMed: 38653122
DOI: 10.1016/j.ijfoodmicro.2024.110693 -
Biotech (Basel (Switzerland)) Mar 2024In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against...
In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as a viable eco-friendly alternative. Microbial volatiles exhibit rapid diffusion rates, facilitating prompt chemical interactions. Moreover, microorganisms possess the capacity to emit volatiles constitutively, as well as in response to biological interactions and environmental stimuli. In addition to volatile compounds, these bacteria demonstrate the ability to produce soluble metabolites with antifungal properties, such as APE Vf, pyoverdin, and fragin. In this study, we identified two strains (BJa3 and MCal1) capable of inhibiting the in vitro mycelial growth of the phytopathogenic fungus , which serves as the causal agent of diseases in sugarcane and maize. Utilizing GC/MS analysis, we detected 47 distinct VOCs which were produced by these bacterial strains. Notably, certain volatile compounds, including 1-heptoxydecane and tridecan-2-one, emerged as primary candidates for inhibiting fungal growth. These compounds belong to essential chemical classes previously documented for their antifungal activity, while others represent novel molecules. Furthermore, examination via confocal microscopy unveiled significant morphological alterations, particularly in the cell wall, of mycelia exposed to VOCs emitted by both species. These findings underscore the potential of the identified BJa3 and MCal1 strains as promising agents for fungal biocontrol in agricultural crops.
PubMed: 38651488
DOI: 10.3390/biotech13020008