Aspergillus Fumigatus Research Articles

A Rapid Colorimetric and Fluorescent Assay of Aspergillus Fumigatus in Food by Loop-Mediated Isothermal Amplification.

Aspergillus fumigatus is a foodborne mycete that can induce recurrent pneumonia, but the current detection methods have insufficient sensitivity and rapidity. Here, we aim to develop an efficient and sensitive loop-mediated isothermal amplification (LAMP) primer set for A. fumigatus detection. First, we designed a novel set of LAMP primers by targeting the Beta-tubulin (β-tub) gene. The LAMP reaction system was optimized by screening reaction temperature and betaine concentration. And then, the specificity of the proposed primers was verified by using 10 interferent microorganism species. The sensitivity of the designed method was compared with that of polymerase chain reaction (PCR) on pure cultures and complex matrix. The accuracy and response time of the method were examined by simulated samples. Our proposed primer set could accurately detect A. fumigatus from different food matrices with no response to other microorganisms. More intriguingly, this method possessed a low limit of detection (2 copies/reaction, 10-fold less than PCR), a short measuring time (<30 min), and a naked-eye readability. A real sample test demonstrates the good recovery rate and accuracy in apple, corn, milk, and other food matrix. Our proposed β-tub primer set provides great potential for rapid assessment of A. fumigatus contamination in food by integrating portable equipment and microscale reaction system.

Incidence and Outcomes of Infectious Keratitis After Corneal Collagen Cross-Linking Over 10 years From a Tertiary Care Center in South India.

The purpose of this study was to report the incidence and outcomes of infectious keratitis after corneal collagen cross-linking (CXL) over 10 years in South India. Patients who underwent CXL for progressive keratoconus between January 2011 and December 2020 and those with infectious keratitis were identified from an electronic database system. The clinical and microbiological profiles of those affected were extracted from the case files and included in the analysis, whereas viral keratitis was excluded. Eleven eyes with post-CXL infectious keratitis were identified, with 3842 CXL procedures (0.21%) occurring in-house, while 3 were referred from outside. The mean age of the patients was 21.8 ± 7.8 years, and 7 (64%) were male. Six eyes (54%) had conventional isotonic CXL, whereas 5 had hypotonic CXL when pachymetry was <400 μm. Six eyes (54%) presented with hypopyon at a median of 3 days after CXL. Culture of the corneal scrapings grew methicillin-sensitive Staphylococcus aureus in 4 patients, methicillin-sensitive Staphylococcus epidermidis in 2, Aspergillus fumigatus in 1, Aspergillus flavus in 1, Haemophilus parainfluenzae in 1, and no organisms in 2 patients. Almost all the isolates were resistant to ciprofloxacin and other fluoroquinolones. The majority of eyes responded well to intensive topical antibiotics guided by antibiograms and regained 6/18 vision (median). Therapeutic keratoplasty was needed in 2 eyes while cyanoacrylate glue was needed in another 2 eyes. Post-CXL infections are rare, most frequently caused by antibiotic-resistant commensals, and resemble the clinical spectrum and outcomes of non-CXL-related infectious keratitis in most cases.

The mammalian Ire1 inhibitor, 4µ8C, exhibits broad anti-Aspergillus activity in vitro and in a treatment model of fungal keratitis

ObjectiveThe fungal unfolded protein response consists of a two-component relay in which the ER-bound sensor, IreA, splices and activates the mRNA of the transcription factor, HacA. Previously, we demonstrated that hacA is essential for Aspergillus fumigatus virulence in a murine model of fungal keratitis (FK), suggesting the pathway could serve as a therapeutic target. Here we investigate the antifungal properties of known inhibitors of the mammalian Ire1 protein both in vitro and in a treatment model of FK.MethodsThe antifungal activity of Ire1 inhibitors was tested against conidia of several A. fumigatus isolates by a broth microdilution assay and against fungal biofilm by XTT reduction. The influence of 4μ8C on hacA mRNA splicing in A. fumigatus was assessed through gel electrophoresis and qRT-PCR of UPR regulatory genes. The toxicity and antifungal profile of 4μ8C in the cornea was assessed by applying drops to uninfected or A. fumigatus-infected corneas 3 times daily starting 4 hours post-inoculation. Corneas were evaluated daily through slit-lamp imaging and optical coherence tomography, or at endpoint through histology or fungal burden quantification via colony forming units.ResultsAmong six Ire1 inhibitors screened, the endonuclease inhibitor 4μ8C displayed the strongest antifungal profile with an apparent fungicidal action. The compound both blocked conidial germination and hyphal metabolism of A. fumigatus Af293 in the same concentration range that blocked hacA splicing and UPR gene induction (60-120 µM). Topical treatment of sham-inoculated corneas with 0.5 and 2.5 mM 4μ8C did not impact corneal clarity, but did transiently inhibit epithelialization of corneal ulcers. Relative to vehicle-treated Af293-infected corneas, treatment with 0.5 and 2.5 mM drug resulted in a 50% and &amp;gt;90% reduction in fungal load, respectively, the latter of which corresponded to an absence of clinical signs of infection or corneal pathology.ConclusionThe in vitro data suggest that 4μ8C displays antifungal activity against A. fumigatus through the specific inhibition of IreA. Topical application of the compound to the murine cornea can furthermore block the establishment of infection, suggesting this class of drugs can be developed as novel antifungals that improve visual outcomes in FK patients.

Integrated multi-omics identifies pathways governing interspecies interaction between A. fumigatus and K. pneumoniae.

Polymicrobial co- and superinfections involving bacterial and fungal pathogens pose serious challenges for diagnosis and therapy, and are associated with elevated morbidity and mortality. However, the metabolic dynamics of bacterial-fungal interactions (BFI) and the resulting impact on disease outcome remain largely unknown. The fungus Aspergillus fumigatus and the bacterium Klebsiella pneumoniae are clinically important pathogens sharing common niches in the human body, especially in the lower respiratory tract. We have exploited an integrated multi-omics approach to unravel the complex and multifaceted processes implicated in the interspecies communication involving these pathogens in mixed biofilms. In this setting, A. fumigatus responds to the bacterial challenge by rewiring its metabolism, attenuating the translational machineries, and by connecting secondary with primary metabolism, while K. pneumoniae maintains its central metabolism and translation activity. The flexibility in the metabolism of A. fumigatus and the ability to quickly adapt to the changing microenvironment mediated by the bacteria highlight new possibilities for studying the impact of cross-communication between competing interaction partners. The data underscore the complexity governing the dynamics underlying BFI, such as pronounced metabolic changes mounted in A. fumigatus interacting with K. pneumoniae. Our findings identify candidate biomarkers potentially exploitable for improved clinical management of BFI.

NCMP-29. BRAIN LESIONS IN A TEEN WITH NEWLY DIAGNOSED T-CELL ALL AND SARS-COV-2 INFECTION

Abstract T-cell Lymphoblastic Leukemia (T-cell ALL) accounts for up to 15% of all newly diagnosed cases of acute lymphoblastic leukemia in pediatric patients (0-18 years old). Patients are at risk of opportunistic infections during induction therapy with up to 2% developing blood stream infections when their absolute neutrophil count is above 1,500. We report a case of a 15-year-old female with High-Risk T-cell ALL, CNS1 (negative CNS disease), presenting with three days of headaches, photophobia, and non-neutropenic fever. She completed induction chemotherapy one week earlier with vincristine, daunorubicin, calaspargase and a 28-day course of dexamethasone. On physical exam, she had no focal deficits or changes in sensation or strength. CBC was notable for a white blood cell count: 7500, hemoglobin: 8.6, platelets: 328,000 and ANC (Absolute Neutrophil Count): 4700. The patient was also COVID positive on admission. A contrast enhanced MRI brain demonstrated multiple diffusion restricting and peripherally enhancing lesions, concerning for intracranial abscesses. Neurosurgery performed a burr hole craniotomy and aspirated 5 mL of purulent drainage, the culture of which grew Aspergillus fumigatus complex. The patient was started empirically on Voriconazole, in addition to broad spectrum antibiotic coverage pending culture results, due to excellent CNS penetration and proven superiority to amphotericin-based therapy for invasive aspergillosis. Micafungin was added due to CT chest demonstrating nodular infiltrates, suggesting primary pulmonary aspergillosis with CNS dissemination. The patient improved symptomatically without further sequelae. Patients with COVID-19 on prolonged courses of corticosteroids are at higher risk of developing fungal co-infections regardless of neutrophil count. While pulmonary aspergillosis is the most common location of a COVID-19 aspergillus coinfection, there have been documented reports of intracranial micro-abscesses. Contrast-enhanced brain MRI should be obtained in any patient with a recent history of COVID-19 presenting with new neurological symptoms, especially in a patient with a recent history of corticosteroids.

Zebrafish (Danio rerio) as a Model System to Investigate the Role of the Innate Immune Response in Human Infectious Diseases

The zebrafish (Danio rerio) has emerged as a valuable model for studying host-pathogen interactions due to its unique combination of characteristics. These include extensive sequence and functional conservation with the human genome, optical transparency in larvae that allows for high-resolution visualization of host cell-microbe interactions, a fully sequenced and annotated genome, advanced forward and reverse genetic tools, and suitability for chemical screening studies. Despite anatomical differences with humans, the zebrafish model has proven instrumental in investigating immune responses and human infectious diseases. Notably, zebrafish larvae rely exclusively on innate immune responses during the early stages of development, as the adaptive immune system becomes fully functional only after 4–6 weeks post-fertilization. This window provides a unique opportunity to isolate and examine infection and inflammation mechanisms driven by the innate immune response without the confounding effects of adaptive immunity. In this review, we highlight the strengths and limitations of using zebrafish as a powerful vertebrate model to study innate immune responses in infectious diseases. We will particularly focus on host-pathogen interactions in human infections caused by various bacteria (Clostridioides difficile, Staphylococcus aureus, and Pseudomonas aeruginosa), viruses (herpes simplex virus 1, SARS-CoV-2), and fungi (Aspergillus fumigatus and Candida albicans).

Investigation of Potent Antifungal Metabolites from Marine Streptomyces bacillaris STR2 (MK045300) from Western Algeria

Fungal infections significantly threaten public health, and many strains are resistant to antifungal drugs. Marine Actinobacteria have been identified as the generators of powerful bioactive compounds with antifungal activity and can be used to address this issue. In this context, strains of Actinomycetes were isolated from the marine area of Rachgoun Island, located in western Algeria. The isolates were phenotypically and genetically characterized. The most potent antifungal isolate was selected, and its crude extract was purified and characterized by the GC/MS method. The results revealed that the STR2 strain showed the strongest activity against at least one target fungal species tested on a panel of fungal pathogens, including Candida albicans, Aspergillus fumigatus, Aspergillus niger, and Fusarium oxysporum. The molecular assignment of the STR2 strain based on the 16S rRNA gene positioned this isolate as a Streptomyces bacillaris species. The presence of safranal (2,3-dihydro-2,2,6-trimethylbenzaldehyde) in the crude chloroform extract of Streptomyces bacillaris STR2 strain was discovered for the first time in bacteria using chromatographic analysis of its TLC fractions. Moreover, certain molecules of biotechnological interest, such as phenols, 1,3-dioxolane, and phthalate derivatives, were also identified. This study highlights the potential of marine actinomycetes to produce structurally unique natural compounds with antifungal activity.

The epidemiological characteristics of invasive pulmonary aspergillosis and risk factors for treatment failure: a retrospective study

ObjectiveThe incidence of invasive pulmonary aspergillosis (IPA) is increasing gradually. This study analysed the epidemiological characteristics and prognostic factors of patients with IPA and explored the risk factors affecting prognosis.Materials and methodsThe clinical data and treatment of 92 patients with IPA were retrospectively analysed, and the patients were followed for 12 weeks. Patients were divided into an effective treatment group and an ineffective treatment group, and the risk factors affecting prognosis were discussed.ResultsA total of 92 patients met the IPA inclusion criteria, and the most common genus of Aspergillus was Aspergillus fumigatus. The incidence of IPA was highest in patients with malignant tumours. IPA often coexisted with infections caused by other pathogens. We divided the patients into an effective treatment group and an ineffective treatment group according to prognosis. Compared with those in the effective treatment group, the procalcitonin (PCT) level, lactate dehydrogenase-to-albumin ratio (LDH/ALB) and neutrophil-to-lymphocyte ratio (NLR) in the ineffective treatment group were greater, the serum albumin level was lower, and the imaging findings revealed less nodules and bronchial wall thickening (P < 0.05). Among these factors, a decrease in the serum albumin concentration, an increase in the PCT level, coinfection and less bronchial wall thickening on imaging were independent risk factors for aspergillosis treatment failure.ConclusionA decreased albumin level, an elevated PCT level, coinfection, and less bronchial wall thickening were independent risk factors for treatment failure in patients with IPA. Attention should be given to the albumin level, coinfection status and imaging findings of patients.

Enhanced antifungal activity of siRNA-loaded anionic liposomes against the human pathogenic fungus Aspergillus fumigatus.

We developed siRNA-loaded anionic liposomes, co-encapsulating low-dose amphotericin B, to enhance siRNA penetration through the fungal cell wall of Aspergillus fumigatus. Targeting mRNAs of three key genes, these liposomes visibly inhibited fungal growth, demonstrating for the first time the antifungal potential of siRNA against human fungal pathogens.

Tracking the uptake of labelled host-derived extracellular vesicles by the human fungal pathogen Aspergillus fumigatus

Abstract Extracellular vesicles (EVs) have gained attention as facilitators of intercellular as well as interkingdom communication during host-microbe interactions. Recently we showed that upon infection, host polymorphonuclear leukocytes produce antifungal EVs targeting the clinically important fungal pathogen Aspergillus fumigatus; however, the small size of EVs (&amp;lt; 1 µm) complicates their functional analysis. Here, we employed a more tractable, reporter-based system to label host alveolar epithelial cell-derived EVs and enabled their visualisation during in vitro A. fumigatus interaction. Fusion of EV marker proteins (CD63, CD9, and CD81) with a Nanoluciferase (NLuc) and a green fluorescent protein (GFP) facilitated their relative quantification by luminescence and visualization by a fluorescence signal. The use of an NLuc fused with a GFP is advantageous as it allows for quantification and visualisation of EVs simultaneously without additional external manipulation and to distinguish subpopulations of EVs. Using this system, visualisation and tracking of EVs was possible using confocal laser scanning microscopy and advanced imaging analysis. These experiments revealed the propensity of host cell-derived EVs to associate with the fungal cell wall and ultimately colocalize with the cell membrane of A. fumigatus hyphae in large numbers. In conclusion, we have created a series of tools to better define the complex interplay of host-derived EVs with microbial pathogens.

Clinical applications of immunoglobulin G against different individual Aspergillus species for the diagnosis of chronic pulmonary aspergillosis among at-risk populations

ABSTRACT Aspergillus fumigatus-specific IgG is often used as a diagnostic test for chronic pulmonary aspergillosis (CPA), but few studies have evaluated the performance and serology of IgGs from species other than A. fumigatus. In this study, we evaluated the serology and performance of different Aspergillus species-specific IgG antibodies in patients with CPA and at-risk populations and whether different Aspergillus species-specific IgGs could be of clinical utility and aid in the diagnosis of CPA caused by all Aspergillus species. A total of 187 participants were included between 2020 and 2022 (12 with CPA, 75 with old tuberculosis [TB], 45 with active TB and 55 with bronchiectasis). We measured the serum Aspergillus fumigatus, flavus, terreus, niger-specific, and mixed Aspergillus IgG levels (Phadia ImmunoCap). The correlation was the strongest between A. fumigatus and A. niger (Spearman’s rank: 0.940), followed by A. niger and A. flavus (Spearman’s rank: 0.915). A. terreus-specific IgG was less strongly correlated with the other three Aspergillus species-specific IgG (Spearman’s rank: 0.828–0.849). A. flavus (4 of 6, 67%) was the dominant species. Using the at-least-one-positive approach, the highest performance was obtained when A. fumigatus and A. flavus IgGs were used (sensitivity, 0.75; specificity, 0.84). Significant cross-reactivity exists among different Aspergillus-species IgGs although the correlation may be less significant for A. terreus. In addition to the commonly used A. fumigatus IgG test, IgGs specific to local prevalent Aspergillus species may provide additional clinical utility.

Urban Pigeons as Reservoirs of Critical Pathogens: Improved protocol for sequencing pigeon faeces in disease monitoring

The spread of pathogens by animals is a serious issue around the world that causes a severe threat to human health. Feral pigeons (Columba livia forma domestica) that live in urban areas are zoonotic carriers of various pathogens that can be transmitted to humans by faecal contamination. This study aimed to detect the presence of bacterial, viral, and specifically fungal pathogens in pigeon faeces based on the World Health Organization's (WHO) priority pathogen list published in 2022. Fresh faecal samples were collected at Uppsala, Central Station, and Svandammen, the pigeons' most relevant gathering spots and feeding sites. Genomic DNA was directly extracted from these samples, and ScilifeLab performed High throughput sequencing through Oxford Nanopore Technologies(ONT) (PromethION). Metagenomic analysis revealed that most of the critically prioritized viral and bacterial pathogens listed by WHO were present in pigeon faeces. Regarding fungal pathogens, which were the main objective of this study, samples from both studied locations contained all critical, high and, medium-important fungal pathogens published in the WHO list, such as Aspergillus fumigatus, Candida albicans, Candida auris, Cryptococcus neoformans, Nakaseomyces glabratus, Candida tropicalis, and Cryptococcus gattii. These fungal pathogens pose the risk of invasive fungal diseases and severe infections in low-immunity individuals and vulnerable populations. The findings indicate the importance of conducting further research to comprehensively understand potential exposure to feral pigeons. Furthermore, keeping pigeons away from sensitive areas, such as hospitals, and implementing measures to control pigeon populations can significantly decrease the spread of pathogens.

Pulmonary Aspergillosis: An Observation from a Tertiary Care Hospital of Western Uttar Pradesh

Background: Aspergillus is the most frequently occurring fungal infection in immunocompromised patients with a high mortality rate. Invasive pulmonary aspergillosis is the most serious entity on the spectrum of pulmonary aspergillosis. Limited studies on the occurrence of pulmonary aspergillosis from this geographical area prompted us to carry out this study. Materials and Methods: This hospital-based cross-sectional observational study was carried out in the Postgraduate Department of Microbiology of a tertiary care medical teaching hospital in western Uttar Pradesh for one year. A total of 1032 respiratory samples were subjected for isolation and identification of fungal pathogens by direct microscopic examination (KOH mount) and culture on Sabouraud dextrose agar. Results: The isolation rate of pulmonary aspergilli was 6.97%. The majority of the respiratory samples received were sputum 900 (87.2%) followed by bronchoalveolar lavage fluid 132 (12.7%). The pulmonary pathology was predominantly seen in the age group of 41–50 years (25%). Male patients (69%) were predominant. The majority of the samples (50%) were from the respiratory medicine ward followed by the respiratory medicine ICU (25%). Aspergillus fumigatus (58%) was the predominant species isolated followed by Aspergillus flavus (25%). Conclusion: Isolation of Aspergillus species from patients of pulmonary pathology needs to be correlated clinically to rule out colonization as they may need proper antifungal treatment. Indiscriminate use of antifungals may lead to the emergence of antifungal drug resistance.

Prevalence of inhaled allergen sensitization among patients with suspected allergic diseases in Sichuan province: 3-year data from a single center.

Allergic diseases are becoming increasingly common, and they are a threat to people's health. Exploring the distribution characteristics of allergen-specific immunoglobulin E (sIgE) in people from Sichuan province, southwest China, can provide clinical epidemiological data. This study enrolled 12,204 consecutive patients with suspected allergies from May 2018 to May 2021. Among the patients, 4206 were diagnosed with allergic rhinitis or asthma. The Rayto Lumiray 1600 detection system and sIgE and total IgE (tIgE) detection kits were used to measure the levels of nine common sIgE and tIgE. sIgE ≥ 0.35 IU/mL was considered positive. The sensitization rate of D1 (Dermatophagoides pteronyssinus) is the highest (22.97%), followed by D2 (Dermatophagoides farinae) (23.33%); M3 (Aspergillus fumigatus) has the lowest positive rate (1.5%). E5 (Canis familiaris) and I6 (Blatella germanica) exhibited relatively high sensitization rates (8.64% and 12.35%, respectively). Allergen sensitization was significantly higher in men than in women. Moreover, 90.3% of sensitization samples from D1 were combined with at least one of the other eight allergens. Similarly, a positive correlation was demonstrated between D1, D2, and E1 (Felis domesticus). In addition, patients with allergic rhinitis (91.88% and 91.54%, respectively), allergic asthma (72.44% and 74.01%, respectively), and allergic rhinitis with asthma (92.12% and 93.22%, respectively) were mainly sensitized to D1 and D2. D1, D2, I6, and E5 are the main allergens. Moreover, D1 and D2 are the main allergens in patients with respiratory allergic diseases. Research focusing on the distribution of allergens and the characteristics of hypersensitivity in different people helps prevent, diagnose, and treat allergic diseases.

Determination of some mycotoxins from poultry feed in Baghdad city

The aims of this study were to determine some mycotoxins and to isolate the fungi from chicken feed samples from broiler and layer farms in Baghdad city. The isolation rate (percentage) of fungi from poultry feed samples was Aspergillus niger 17.7%, Aspergillus flavus 14.7%, Aspergillus fumigatus 12.4%, Aspergillus ochraceus 10.7%, Penicillium spp. 9.3%, Fusarium spp. 9.3%, Rhizopus spp. 8.4%, Mucar spp. 8.4%, Absidia spp. 7.6% and Chrysonilia sitophila 1.5%, while the most common yeast genera were Candida spp. 44.8%, Candida albicans 20.7%, Cryptococcus neoformans 17.3%, Geotricum candidum 12% and Trichosorom spp. 5.2%. The mycotoxins ochratoxin A (OTA), deoxynivalenol (DON), fumonisin B1 (FB1) and zearalenone (ZON) were detected, and the percentages of these mycotoxins were 43.1%, 27.2%, 21.1% and 8.6%, respectively. This study indicates that the presence of mold that produce mycotoxins in poultry feed increases the risk of mycotoxins in feed, meat, eggs, etc. of animals and therefore humans, and we need to raise awareness of the Ministry of Agriculture and Health to prevent these measures to reduce the mycotoxin levels in poultry products.

Comparison of ISSR indicators in distinguishing aspergillus fumigatus isolates from different sources

Comparison of ISSR indicators in distinguishing aspergillus fumigatus isolates from different sources

Ozonation procedure for removal of mycotoxins in maize: A promising screening approach for improvement of food safety.

Mycotoxins are well known secondary metabolites of various fungi. They pose a significant threat to human and animal when present in food or feed. They can be responsible for losses in grain production and in livestock or human intoxication. In this study, several mycotoxins were detected in Aspergillus fumigatus contaminated maize kernels. The contaminated kernels were treated with gaseous ozone at a concentration of 500 and 3000 ppm for 1 hour. Depending on the specific compound, the contamination level was reduced by up to 100%. This screening research showed that a concentration of ozone as high as 3000 ppm could be sufficient to completely remove several toxic compounds from the maize matrix.

Spectrum and Antifungal Drug Resistance among Fungal Pathogens Isolated from Prison Inmates in Nairobi, Kenya

Background The emergence of antifungal resistance in fungal pathogens highlights the need for local epidemiological data to guide empirical therapy in clinical settings. Fungal research and anti-fungal drug resistance studies are limited in developing countries; hence, there is a need for burden estimation in low- and middle-income countries. This study aimed to determine the spectrum of fungal pathogens and the anti-fungal resistance profile of fungal pathogens isolated from the respiratory and urinary tracts of prison inmates in Nairobi, Kenya. Methods A cross-sectional study was conducted in which sputum and urine samples were obtained from inmates presenting with symptoms of respiratory and urogenital infections at a prison outpatient clinic. One hundred and sixty-two samples were collected and subjected to fungal investigation using standard protocols. Susceptibility to fluconazole, itraconazole, and voriconazole was assessed using standard broth microdilution. Clinical and sociodemographic data were obtained using a structured questionnaire. Results From the 162, 94 samples were positive for fungal pathogens, with an overall prevalence of 58%. Seventeen (18%) of the isolated fungi were Aspergillus fumigatus, Aspergillus flavus and Histoplasma. There was a statistically significant difference between fungal pathogens isolated from the respiratory and urogenital tracts in both sexes (p&lt;0.05). Antifungal susceptibility testing against itraconazole showed 2 of Aspergillus flavus and Aspergillus fumigatus were resistant. Conclusion Mycological agents are significant causes of respiratory and UTI infections among prison inmates, which could be attributed to prison conditions and misdiagnosis as bacterial infections. This highlights the need for specific control measures to reduce exposure to fungal infections in prisons and in the general population.

Degradative potential of laccase and manganese peroxidase to mycotoxins on infected maize grains by fungi with docking interaction studies

Fungal infection in agricultural grains is a global problem, particularly if it is accompanied by mycotoxin production. In this study, the degradation of mycotoxins by laccase and manganese peroxidase was investigated. Aspergillus flavus, Aspergillus fumigatus, and Fusarium graminearum were recorded in infected maize grains. Aflatoxin B1 (AF B1) was detected (from 3.38 to 2.60 ppm) on the infected samples by fungi compared to other detected aflatoxins. Trichothecene (T-2) toxin and deoxynivalenol (DON) were recorded with concentrations ranging from 0.464 to 0.184 ppm and 0.370 to 0.214 ppm, respectively. The addition of laccase and manganese peroxidase to the inoculated medium with A. flavus and F. graminearum individually degraded the produced AF B1, B2, G1, G2, T-2 toxin, and DON from 5.0, 1.33, 0.76, 0.61, 0.63, and 0.38 ppm to 2.77, 0.66, 0.37, 0.15, 0.45, and 0.38 ppm using laccase, to 3.08, 1.25, 0.61, 0.39, 0.55, and 0.36 ppm using manganese peroxidase. The computational technique (docking) demonstrated the laccase and manganese peroxidase activities on aflatoxin and DON degradation. Consequently, the results suggested that laccase (PDB ID: 1HFU) and manganese peroxidase (PDB ID: 1MNP) promise innovative activity toward aflatoxin degradation, while 1HFU has more effect than 1MNP on DON degradation.

Intrinsic Natural Resistance of Various Plant Pathogens to Ipflufenoquin, a New DHODH (Dihydroorotate Dehydrogenase)-inhibiting Fungicide, in Relation to Unaltered Amino Acid Sequence of the Target Site.

In recent years, increasingly stringent pesticide regulations have made the development of new chemistries challenging. Under these regulations, the new fungicide ipflufenoquin (FRAC Code 52) was first released in Japan. Its mode of action is new; it inhibits dihydroorotate dehydrogenase (DHODH), a key enzyme in the biosynthesis of pyrimidine-based nucleotides. However, because it is a single-site inhibitor, the risk of resistance developing in pathogens must be carefully considered. The risk for dual use of DHODH inhibitors in agriculture and medicine has also become a great concern because a new antifungal olorofim is under development against human pathogens now and cross-resistance has recently been reported between ipflufenoquin and olorofim in Aspergillus fumigatus. In this study, the sensitivity to ipflufenoquin was examined in culture and in plants using "baseline" isolates, which had never been exposed to DHODH inhibitors. Isolates of Alternaria alternata, Botrytis cinerea, B. elliptica, Colletotrichum fioriniae, C. fructicola, C. nymphaeae, C. orbiculare, C. siamense, C. tropicale, C. truncatum, and Sclerotinia sclerotiorum were highly sensitive to ipflufenoquin in culture, but isolates of Coniella vitis, Corynespora cassiicola, Pseudocercospora fuligena, and Rhizoctonia solani were inherently resistant. Ipflufenoquin had low efficacy against C. cassiicola and C. vitis after inoculation of cucumber and grapevine leaves, respectively. To understand the mechanism of natural resistance, we analyzed the partial sequence of pyrE genes, which encode the DHODH enzyme, but did not find any differences in the deduced amino acids that were thought to be associated with resistance. Thus, mechanisms other than target-site mutations might be involved in the intrinsic resistance.