-
Waste Management (New York, N.Y.) Jun 2024This study aims to investigate the microbiological working environment of biowaste workers, focusing on airborne fungal and bacterial species exposure, size...
This study aims to investigate the microbiological working environment of biowaste workers, focusing on airborne fungal and bacterial species exposure, size distribution, and species on workers' hands. The research, conducted across six plants with 45 personal exposure assessments, revealed a total of 150 bacterial species and 47 fungal species on workers' hands, including 19 and 9 species classified in risk class 2 (RC2), respectively. Workers' exposure analysis identified 172 bacterial and 32 fungal species, with several in RC2. In work areas, 55 anaerobic bacterial species belonging to RC2 were found. Different species compositions were observed in various particle size fractions, with the highest species richness for anaerobic bacteria in the fraction potentially depositing in the secondary bronchi and for fungi in the pharynx fraction. The geometric mean aerodynamic diameter (D) of RC2 anaerobic bacteria was 3.9 µm, <1.6 µm for Streptomyces, 3.4 µm for Aspergillus, and 2.0 µm for Penicillium. Overlapping species were identified on workers' hands, in their exposure, and in work areas, with Bacillus amyloliquefaciens, Leuconostoc mesenteroides, Bacillus cereus, Enterococcus casseliflavus, and Aspergillus niger consistently present. While the majority of RC2 bacterial species lacked documented associations with occupational health problems, certain bacteria and fungi, including Bacillus cereus, Escherichia coli, Enterobacter, Klebsiella pneumonia, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Lichtheimia corymbifera, Lichtheimia ramosa, and Paecilomyces variotii, have previously been linked to occupational health issues. In conclusion, biowaste workers were exposed to a wide range of microorganisms including RC2 species which would deposit in different parts of the airways.
Topics: Humans; Fungi; Bacteria; Occupational Exposure; Air Microbiology; Hand; Environmental Monitoring; Inhalation Exposure; Air Pollutants, Occupational
PubMed: 38788497
DOI: 10.1016/j.wasman.2024.05.018 -
Toxins May 2024The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the...
The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the surroundings. Chitin is a vital structural element in fungal cell wall. Chitin deacetylase (CDA) can transform chitin into chitosan through deacetylation, providing various biological functions across fungal species. Although this modification is widespread in fungi, the biological functions of CDA enzymes in remain largely unexplored. In this study, we aimed to investigate the biofunctions of the CDA family in . The genome contains six annotated putative chitin deacetylases. We constructed knockout strains targeting each member of the CDA family, including Δ, Δ, Δ, Δ, Δ, and Δ. Functional analyses revealed that the deletion of CDA family members neither significantly affects the chitin content nor exhibits the expected chitin deacetylation function in . However, the Δ strain displayed distinct phenotypic characteristics compared to the wild-type (WT), including an increased conidia count, decreased mycelium production, heightened aflatoxin production, and impaired seed colonization. Subcellular localization experiments indicated the cellular localization of CDA6 protein within the cell wall of filaments. Moreover, our findings highlight the significance of the CBD1 and CBD2 structural domains in mediating the functional role of the CDA6 protein. Overall, we analyzed the gene functions of CDA family in , which contribute to a deeper understanding of the mechanisms underlying aflatoxin contamination and lay the groundwork for potential biocontrol strategies targeting .
Topics: Aspergillus flavus; Amidohydrolases; Aflatoxins; Fungal Proteins; Chitin; Cell Wall
PubMed: 38787069
DOI: 10.3390/toxins16050217 -
Journal of Fungi (Basel, Switzerland) May 2024Autophagy, a conserved cellular recycling process, plays a crucial role in maintaining homeostasis under stress conditions. It also regulates the development and...
Autophagy, a conserved cellular recycling process, plays a crucial role in maintaining homeostasis under stress conditions. It also regulates the development and virulence of numerous filamentous fungi. In this study, we investigated the specific function of ATG8, a reliable autophagic marker, in the opportunistic pathogen . To investigate the role of in , the deletion and complemented mutants of were generated according to the homologous recombination principle. Deletion of showed a significant decrease in conidiation, spore germination, and sclerotia formation compared to the WT and strains. Additionally, aflatoxin production was found severely impaired in the ∆ mutant. The stress assays demonstrated that ATG8 was important for response to oxidative stress. The fluorescence microscopy showed increased levels of reactive oxygen species in the ∆ mutant cells, and the transcriptional result also indicated that genes related to the antioxidant system were significantly reduced in the ∆ mutant. We further found that ATG8 participated in regulating the pathogenicity of on crop seeds. These results revealed the biological role of ATG8 in , which might provide a potential target for the control of and AFB1 biosynthesis.
PubMed: 38786704
DOI: 10.3390/jof10050349 -
Journal of Fungi (Basel, Switzerland) Apr 2024The tomato ( Mill.) is considered to be one of the products with the highest demand due to its nutritional value; however, it is susceptible to infection by fungi during...
The tomato ( Mill.) is considered to be one of the products with the highest demand due to its nutritional value; however, it is susceptible to infection by fungi during its pre- and postharvest stages. In this research, three commercial products (1% Citrocover, 1% Citro 80, and 0.002% Microdyn) and two coatings based on 1.0% chitosan/0.1% lime or 0.1% orange essential oils were evaluated in vitro and on Saladette tomatoes that were previously inoculated with four postharvest fungi. The application of the commercial citrus-based product Citrocover was highly effective in reducing the in vitro development of , , and , but not . The sanitizer Microdyn promoted infections with most fungi. Citrus-based products were effective in reducing infections with in the tomatoes during storage. Overall, mycotoxin production was very low for all treatments. The use of commercial citrus-based products and coatings did not alter the weight loss, firmness, or total soluble solid contents of the treated tomatoes. The changes observed were, rather, associated with the normal ripening process of Saladette tomatoes. The commercial citrus-based products satisfactorily controlled the in vitro growth of the fungi , , and .
PubMed: 38786664
DOI: 10.3390/jof10050309 -
Antibiotics (Basel, Switzerland) May 2024Simple low-cost, nontoxic, environmentally friendly plant-extract-based polymer films play an important role in their application in medicine, the food industry, and...
Simple low-cost, nontoxic, environmentally friendly plant-extract-based polymer films play an important role in their application in medicine, the food industry, and agriculture. The addition of silver nanoparticles to the composition of these films enhances their antimicrobial capabilities and makes them suitable for the treatment and prevention of infections. In this study, polymer-based gels and films (AgRonPVA) containing silver nanoparticles (AgNPs) were produced at room temperature from fresh red onion peel extract ("Ron"), silver nitrate, and polyvinyl alcohol (PVA). Silver nanoparticles were synthesized directly in a polymer matrix, which was irradiated by UV light. The presence of nanoparticles was approved by analyzing characteristic local surface plasmon resonance peaks occurring in UV-Vis absorbance spectra of irradiated experimental samples. The proof of evidence was supported by the results of XRD and EDX measurements. The diffusion-based method was applied to investigate the antimicrobial activity of several types of microbes located in the environment of the produced samples. Bacteria ATCC 29213, ATCC BAA 747, and ATCC 15442; yeasts CBS 8836 and ATCC 90028; and microscopic fungi assays BTL G-33 and BTL G-38 were used in this investigation. The greatest effect was observed on Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa bacteria, defining these films as potential candidates for antimicrobial applications. The antimicrobial features of the films were less effective against fungi and the weakest against yeasts.
PubMed: 38786169
DOI: 10.3390/antibiotics13050441 -
Journal of the Science of Food and... May 2024The recurrent contaminations of feed materials with mycotoxigenic fungi can endanger both farmed animals and humans. Biosynthesized nanomaterials are assumingly the...
BACKGROUND
The recurrent contaminations of feed materials with mycotoxigenic fungi can endanger both farmed animals and humans. Biosynthesized nanomaterials are assumingly the ideal agents to overcome fungal invasion in feed/foodstuffs, especially when utilizing sustainable sources for synthesis. Herein, the phycosynthesis of selenium nanoparticles (SeNPs) was targeted using Cystoseira myrica algal extract (CE), and the conjugation of CE/SeNPs with chitosan nanoparticles (NCt) to produce potential antifungal nanocomposites for controlling Aspergillus flavus isolates in fish feed.
RESULTS
The phycosynthesis of SeNPs with CE was effectually carried out and validated using visible/UV analysis, X-ray diffraction and transmission microscopy; CE/SeNPs had diameters of 8.7 nm and spherical shapes. NCt/CE/SeNPs nanocomposite (173.3 nm mean diameter) was achieved and the component interactions were validated via infrared spectroscopic analysis. The antifungal assessment of screened nanomaterials against three Aspergillus flavus strains indicated that NCt/CE/SeNPs exceeded the fluconazole action using qualitative/quantitative assays. Severe alteration/distortions in A. flavus mycelial structure and morphology were microscopically observed within 48 h of NCt/CE/SeNPs treatment. The treatment of feed ingredients (crushed corn and feed powder) by blending with nanomaterials (NCt, CE/SeNPs and NCt/CE/SeNPs) led to significant reduction in A. flavus count/growth after storage for 7 days; NCt/CE/SeNPs could completely inhibit any fungal growth in feed material.
CONCLUSION
The pioneering phycosynthesis of CE/SeNPs and their nanoconjugation with NCt generated bioactive antifungal agents to control A. flavus strains. The innovatively constructed NCt/CE/SeNPs nanocomposite is advised for application as an effectual, biosafe and natural fungicidal conjugate for the protection of fish feed from mycotoxigenic fungi. © 2024 Society of Chemical Industry.
PubMed: 38775588
DOI: 10.1002/jsfa.13604 -
AMB Express May 2024The growth of material science and technology places a high importance on the creation of better processes for the synthesis of copper nanoparticles. So that, an easy,...
The growth of material science and technology places a high importance on the creation of better processes for the synthesis of copper nanoparticles. So that, an easy, ecological, and benign process for producing copper nanoparticles (CuNPs) has been developed using candy leaf (Stevia rebaudiana) leaves aqueous extract for the first time. UV-visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Fourier transmission infrared (FTIR), and zeta potential were applied to demonstrate strong characterization for the biosynthesized stevia-CuNPs. The UV-visible absorbance at 575 nm of surface plasmon resonance (SPR) was 1.2. The particle size mean diameter was recorded as 362.3 nm with - 10.8 mV zeta potential. The HR-TEM scanning revealed 51.46-53.17 nm and spherical-shaped stevia-CuNPs surrounded by coat-shell proteins. The cytotoxicity and cytocompatibility activity assay revealed that stevia-CuNPs was safe in lower concentrations and had a significant cell viability reduction in higher concentrations. The produced stevia-CuNPs were applied as antimicrobial agents against eight pathogenic bacteria and five fungi strains. The inhibitory action of the stevia-CuNPs was more pronounced in bacteria than in fungi, and they likewise demonstrated further inhibition zones in Staphylococcus aureus (50.0 mm) than in Aspergillus flavus (55.0 mm). With inhibition zone sizes of 50.0 mm and 47.0 mm and 50 µg/ml minimum inhibitory concentration, S. aureus and A. flavus were the most inhibited pathogens. The minimum lethal effect (MLC) estimate for S. aureus was 50 µg/ml, whereas 75 µg/ml for A. flavus. The stevia-CuNPs mode of action was characterized as bactericidal/fungicidal as the ratio of MIC to MLC was estimated to be equal to or less than 2. After all, stevia-CuNPs could be used as an alternative to commercial antibiotics to solve the problem of multidrug-resistant (MDR) microorganisms.
PubMed: 38761277
DOI: 10.1186/s13568-024-01707-2 -
International Journal of Food... Jun 2024Aspergillus flavus is a notorious fungus that contaminates food crops with toxic aflatoxins, posing a serious threat to human health and the agricultural economy. To...
Aspergillus flavus is a notorious fungus that contaminates food crops with toxic aflatoxins, posing a serious threat to human health and the agricultural economy. To overcome the inadequacy of traditional control methods and meet consumer preferences for natural-sources additives, there is an urgent demand for novel biocontrol agents that are safe and efficient. This study aims to investigate the antifungal properties of a novel antifungal agent derived from the biologically safe Lactiplantibacillus plantarum WYH. Firstly, antifungal peptides (AFPs) with a molecular weight of less than 3kD, exhibiting remarkable temperature stability and effectively retarding fungal growth in a dose-dependent manner specifically against A. flavus, were concentrated from the fermentation supernatant of L. plantarum WYH and were named as AFPs-WYH. Further analysis demonstrated that AFPs-WYH might exert antifungal effects through the induction of oxidative stress, disruption of mitochondrial function, alteration of membrane permeability, and cell apoptosis in A. flavus. To further validate our findings, a transcriptomics analysis was conducted on A. flavus treated with 2 and 5 mg/mL of AFPs-WYH, which elucidated the potential effect of AFPs-WYH administration on the regulation of genes involved in impairing fungal development and preventing aflatoxin biosynthesis pathways. Overall, AFPs-WYH reduced the A. flavus proliferation and affected the AFB biosynthesis, exhibiting a promising potential for food industry applications as a biopreservative and biocontrol agent.
Topics: Aspergillus flavus; Antifungal Agents; Biological Control Agents; Food Contamination; Lactobacillus plantarum; Fermentation; Peptides; Aflatoxins; Oxidative Stress
PubMed: 38759292
DOI: 10.1016/j.ijfoodmicro.2024.110727 -
Designed Monomers and Polymers 2024A new class of biologically active polyazomethine/pyrazole and their related nanocomposites, polyazomethine/pyrazole/zinc oxide nanoparticles, have been successfully...
A new class of biologically active polyazomethine/pyrazole and their related nanocomposites, polyazomethine/pyrazole/zinc oxide nanoparticles, have been successfully synthesized through the polycondensation technique in the form of polyazomethine pyrazole (PAZm/Py) and polyazomethine/pyrazole/zinc oxide nanoparticles (PAZm/Py/ZnO). The polymeric nanocomposites were prepared with a 5% loading of zinc oxide nanofiller using the same preparation technique, in addition to the help of ultrasonic radiation. The characteristics of the new polymers, such as solubility, viscometry, and molecular weight, were examined. All the polymers were completely soluble in the following solvents: concentrated sulfuric acid, formic acid, dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran. Furthermore, the weight loss of the polyazomethine pyrazole (4, 5, and 6) at 800 °C was 67%, 95%, and 86%, respectively, which indicates the thermal stability of these polymers. At 800 °C, the polyazomethine/pyrazole/zinc oxide nanoparticles (a, b, and c) lost 74%, 68%, and 75% of their weight, respectively. This shows that adding zinc oxide nanoparticles made these compounds more stable at high temperatures. The X-Ray diffraction pattern of the polyazomethine pyrazole (PAZm/Py) shows a number of sharp peaks with varying intensities. The polymers that were studied had straight crystal structures. Furthermore, the measurements of polyazomethine/pyrazole/zinc oxide nanoparticles (PAZm/Py/ZnO) indicate a good merging of zinc oxide nanoparticles into the matrix of polymers. The antimicrobial activity of polymers and polymer nanocomposites was tested against some selected bacteria and fungi. The synthesized polymer (c) shows the highest activity against the two types of gram-negative bacteria selected. Most tested compounds were found to be effective against gram-positive bacteria except polyazomethine pyrazole (PAZm/Py) and polyazomethine pyrazole (PAZm/Py), which do not exhibit any activity. The synthesized polymers and their related nanocomposites were tested for their ability to kill the chosen fungi. All of them were effective against Aspergillus flavus, but only polyazomethine pyrazole (PAZm/Py) and polyazomethine/pyrazole/zinc oxide (PAZm/Py/ZnO) were effective against Candida albicans.
PubMed: 38756722
DOI: 10.1080/15685551.2024.2352897 -
Allergologie Select 2024None.
None.
PubMed: 38756207
DOI: 10.5414/ALX02444E