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Cellular and Molecular Life Sciences :... May 2024Aspergillus ochraceus is the traditional ochratoxin A (OTA)-producing fungus with density-dependent behaviors, which is known as quorum sensing (QS) that is mediated by...
Aspergillus ochraceus is the traditional ochratoxin A (OTA)-producing fungus with density-dependent behaviors, which is known as quorum sensing (QS) that is mediated by signaling molecules. Individual cells trend to adapt environmental changes in a "whole" flora through communications, allowing fungus to occupy an important ecological niche. Signals perception, transmission, and feedback are all rely on a signal network that constituted by membrane receptors and intracellular effectors. However, the interference of density information in signal transduction, which regulates most life activities of Aspergillus, have yet to be elucidated. Here we show that the G protein-coupled receptor (GPCR) to cAMP pathway is responsible for transmitting density information, and regulates the key point in life cycle of A. ochraceus. Firstly, the quorum sensing phenomenon of A. ochraceus is confirmed, and identified the density threshold is 10 spores/mL, which represents the low density that produces the most OTA in a series quorum density. Moreover, the GprC that classified as sugar sensor, and intracellular adenylate cyclase (AcyA)-cAMP-PKA pathway that in response to ligands glucose and HODEs are verified. Furthermore, GprC and AcyA regulate the primary metabolism as well as secondary metabolism, and further affects the growth of A. ochraceus during the entire life cycle. These studies highlight a crucial G protein signaling pathway for cell communication that is mediated by carbohydrate and oxylipins, and clarified a comprehensive effect of fungal development, which include the direct gene regulation and indirect substrate or energy supply. Our work revealed more signal molecules that mediated density information and connected effects on important adaptive behaviors of Aspergillus ochraceus, hoping to achieve comprehensive prevention and control of mycotoxin pollution from interrupting cell communication.
Topics: Quorum Sensing; Aspergillus ochraceus; Signal Transduction; Glucose; Cyclic AMP; Adenylyl Cyclases; Receptors, G-Protein-Coupled; Fungal Proteins; Ochratoxins
PubMed: 38806811
DOI: 10.1007/s00018-024-05160-z -
EFSA Journal. European Food Safety... Apr 2024The food enzyme oryzin (EC 3.4.21.63) is produced with the non-genetically modified strain AE-P by Amano Enzyme Inc. The food enzyme was considered free from viable...
The food enzyme oryzin (EC 3.4.21.63) is produced with the non-genetically modified strain AE-P by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in nine food manufacturing processes. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.1 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1862 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 18,620. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and 31 matches were found, including one food allergen (melon). The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme, particularly in individuals sensitised to melon, cannot be excluded, but would not exceed the risk from consumption of this food. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 38634008
DOI: 10.2903/j.efsa.2024.8713 -
Heliyon Apr 2024Marine fungi represent an important proportion of the microbial diversity in the oceans. They are attractive candidates for biotechnological purposes and industrial...
Marine fungi represent an important proportion of the microbial diversity in the oceans. They are attractive candidates for biotechnological purposes and industrial applications. Despite an increasing interest in mycology, marine fungi associated with sponges and algae have been poorly studied in Mauritius. The objectives of this study were to: 1) use multigene phylogenetic analyses to identify isolated marine fungi; 2) determine the differences in the antimicrobial and antioxidant properties of the fungal extracts; and 3) assess their enzyme activities and dye decolorization potential. Five fungal isolates , , and sp. were identified based on phylogenetic analyses. There was no significant difference in the antimicrobial properties of the liquid and solid media extracts unlike the antioxidant properties (p < 0.05). The solid media extract of (F2-SF) had a minimum inhibitory concentration of 0.156 mg/ml against while (F25-SF) had a minimum inhibitory concentration of 0.313 and 2.5 mg/ml against and . The solid media extract of sp. (F34-SF) had a minimum inhibitory concentration of 0.195 and 1.563 mg/ml against , and . An IC of 78.92 ± 4.71 μg/ml in the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, ferric reducing antioxidant power (FRAP) value of 11.17 ± 0.20 mM Fe/g dry weight extract (DWE) and total phenolic content 360.35 ± 10.31 mg GAE/g DWE was obtained with the solid media extract of (F2-SF). (F25-SF) and sp. (F34-SF) solid media extracts showed lower IC values in the DPPH assay and higher total phenolic content as compared to the liquid media extracts. was a good producer of the enzymes DNAse and lipase and had maximum percentage dye decolorization of 79.40 ± 17.72% on Congo red. An enzymatic index ≥ 2 was found for the DNAse and lipase and the maximum percentage dye decolorization of 87.18 ± 3.80% was observed with on Methylene blue. Regarding sp., it was a moderate producer of the three enzymes amylase, DNAse and protease and had a maximum dye decolorization potential of 56.29 ± 6.51% on Crystal violet. This study demonstrates that Mauritian marine fungi possess good bioactive properties, enzymatic and dye decolorization potentials, that can potentially be considered for use in pharmaceutical and industrial applications.
PubMed: 38623192
DOI: 10.1016/j.heliyon.2024.e28955 -
Antibiotics (Basel, Switzerland) Feb 2024Nowadays, unprecedented health challenges are urging novel solutions to address antimicrobial resistance as multidrug-resistant strains of bacteria, yeasts and moulds...
Nowadays, unprecedented health challenges are urging novel solutions to address antimicrobial resistance as multidrug-resistant strains of bacteria, yeasts and moulds are emerging. Such microorganisms can cause food and feed spoilage, food poisoning and even more severe diseases, resulting in human death. In order to overcome this phenomenon, it is essential to identify novel antimicrobials that are naturally occurring, biologically effective and increasingly safe for human use. The development of gemmotherapy extracts (GTEs) using plant parts such as buds and young shoots has emerged as a novel approach to treat/prevent human conditions due to their associated antidiabetic, anti-inflammatory and/or antimicrobial properties that all require careful evaluations. Seven GTEs obtained from plant species like the olive ( L.), almond ( L.), black mulberry ( L.), walnut ( L.), blackberry ( L.), blackcurrant ( L.) and bilberry ( L.) were tested for their antimicrobial efficiency via agar diffusion and microbroth dilution methods. The antimicrobial activity was assessed for eight bacterial (, , subsp. , , , , and ), five moulds (, , , , ) and one yeast strain (). The agar diffusion method revealed the blackberry GTE as the most effective since it inhibited the growth of three bacterial, four moulds and one yeast species, having considered the total number of affected microorganism species. Next to the blackberry, the olive GTE appeared to be the second most efficient, suppressing five bacterial strains but no moulds or yeasts. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for each GTE and the microorganisms tested. Noticeably, the olive GTE appeared to feature the strongest bacteriostatic and bactericidal outcome, displaying specificity for , and . The other GTEs, such as blueberry, walnut, black mulberry and almond (the list indicates relative strength), were more effective at suppressing microbial growth than inducing microbial death. However, some species specificities were also evident, while the blackcurrant GTE had no significant antimicrobial activity. Having seen the antimicrobial properties of the analysed GTEs, especially the olive and black mulberry GTEs, these could be envisioned as potential antimicrobials that might enhance antibiotic therapies efficiency, while the blackberry GTE would act as an antifungal agent. Some of the GTE mixtures analysed have shown interesting antimicrobial synergies, and all the antimicrobial effects observed argue for extending these studies to include pathological microorganisms.
PubMed: 38391567
DOI: 10.3390/antibiotics13020181 -
Toxins Dec 2023In the context of the mysterious Balkan endemic nephropathy of the 1900s, and the discovery in the 1960s of the potent mycotoxin ochratoxin A, experimental research... (Review)
Review
In the context of the mysterious Balkan endemic nephropathy of the 1900s, and the discovery in the 1960s of the potent mycotoxin ochratoxin A, experimental research projects sought to explore any inter-relationship. Experimental lifetime administration of the toxin to male rats had revealed renal DNA adducts with the toxin, correlated with renal tumours, confirmation of which required molecular evidence. Consequently, production of C-ochratoxin A of a high specific radioactivity was required, practical biosynthetic detail of which had not previously been published. A fermentation study of was carried out during 2002 for a European project, to select for the production of high-quality C-ochratoxin A, necessarily exploring for the maximum diversion of C-sodium acetate into the pentaketide portion of mycotoxin. Experimentation necessarily had to optimise the competitive context of fungal growth dynamics and addition of the biosynthetic precursor in the early days of shaken-flask fermentation before adding the radiolabelled precursor. From optimal fermentation, 50 mg of the C ochratoxin A was supplied within a European project for DNA adduct experimentation, but that proved negative as subsequently published. Experimental description of the radiolabelled ochratoxin A production was later made in a doctoral thesis, but is first publicised here. Further review of the literature reveals an explanation for the published failure to confirm rat DNA/ochratoxin A adduct formation, for which further experimentation is now recommended.
Topics: Male; Animals; Rats; Aspergillus ochraceus; Fermentation; Balkan Nephropathy; Mycotoxins; Ochratoxins
PubMed: 38251225
DOI: 10.3390/toxins16010008 -
Molecules (Basel, Switzerland) Dec 2023Biotransformation of ursonic acid () by two fungal strains CGMCC 3.5324 and CGMCC 3.407 yielded thirteen new compounds (, , -, and -), along with five recognized ones....
Biotransformation of ursonic acid () by two fungal strains CGMCC 3.5324 and CGMCC 3.407 yielded thirteen new compounds (, , -, and -), along with five recognized ones. The structural details of new compounds were determined through spectroscopic examination (NMR, IR, and HR-MS) and X-ray crystallography. Various modifications, including hydroxylation, epoxidation, lactonization, oxygen introduction, and transmethylation, were identified on the ursane core. Additionally, the anti-neuroinflammatory efficacy of these derivatives was assessed on BV-2 cells affected by lipopolysaccharides. It was observed that certain methoxylated and epoxylated derivatives (, , and ) showcased enhanced suppressive capabilities, boasting IC values of 8.2, 6.9, and 5.3 μM. Such ursonic acid derivatives might emerge as potential primary molecules in addressing neurodegenerative diseases.
Topics: Aspergillus ochraceus; Aspergillus oryzae; Crystallography, X-Ray; Biotransformation
PubMed: 38138433
DOI: 10.3390/molecules28247943 -
Chinese Herbal Medicines Oct 2023Gut microbiome is an intricate micro-ecosystem mediating the human health and drug efficacy. (PAL) is an edible and time-honored traditional Chinese medicine. Several...
OBJECTIVE
Gut microbiome is an intricate micro-ecosystem mediating the human health and drug efficacy. (PAL) is an edible and time-honored traditional Chinese medicine. Several pharmacological effects of PAL have been verified and gut bacteria are implied in its therapeutic actions. However, the detailed modulation of PAL on gut bacterial species and on gut fungi remains largely unknown. We, therefore, designed a preliminary experiment in normal mice to reveal the modulation effect of PAL on both gut bacteria and fungi, and explore the interaction between them.
METHODS
Herein, the aqueous extract of PAL was orally administrated to normal C57BL/6 mice for four weeks. The full-length 16S rRNA and ITS1/2 gene sequencing were explored to detect the taxa of gut bacteria and gut fungi after PAL treatment, respectively.
RESULTS
Oral administration of PAL notably enriched anti-inflammatory bacterial species such as spp. and , whereas decreased pro-inflammatory species such as . Simultaneously, PAL increased the abundance of gut fungi , sp. and sp., and decreased . Correlation network analysis identified two co-existing microbial groups (groups 1 and 2) that were negatively associated with each other. The group 1 comprised PAL-enriched bacteria and fungi, while group 2 was mainly normal chow-enriched bacteria and fungi. In group 1, , , and sp. MA 4787 were positively correlated with , and so on. In group 2, , and were positively related to spp.
CONCLUSION
Altogether, this preliminary study first demonstrated the modulation effect of PAL on both gut bacteria and gut fungi, which may shed light on the elucidation of PAL's pharmacological mechanism.
PubMed: 38094014
DOI: 10.1016/j.chmed.2023.02.003 -
Heliyon Nov 2023Essential oils (EOs) are natural products called volatile oils or aromatic and ethereal oils derived from various parts of plants. They possess antioxidant and... (Review)
Review
Essential oils (EOs) are natural products called volatile oils or aromatic and ethereal oils derived from various parts of plants. They possess antioxidant and antimicrobial properties, which offer natural protection against a variety of pathogens and spoilage microorganisms. Studies conducted in the last decade have demonstrated the unique applications of these compounds in the fields of the food industry, agriculture, and skin health. This systematic article provides a summary of recent data pertaining to the effectiveness of EOs and their constituents in combating fungal pathogens through diverse mechanisms. Antifungal investigations involving EOs were conducted on multiple academic platforms, including Google Scholar, Science Direct, Elsevier, Springer, Scopus, and PubMed, spanning from April 2000 to October 2023. Various combinations of keywords, such as "essential oil," "volatile oils," "antifungal," and " species," were used in the search. Numerous essential oils have demonstrated both and antifungal activity against different species of , including , , A. , A. , and A. ochraceus. They have also exhibited efficacy against other fungal species, such as species, , and Alternaria. The findings of this study offer novel insights into inhibitory pathways and suggest the potential of essential oils as promising agents with antifungal and anti-mycotoxigenic properties. These properties could make them viable alternatives to conventional preservatives, thereby enhancing the shelf life of various food products.
PubMed: 37954273
DOI: 10.1016/j.heliyon.2023.e21386 -
Mycobiology 2023is one of the largest and diverse genera of fungi with huge economical, biotechnological, and social significance. Taxonomically, is divided into six subgenera...
is one of the largest and diverse genera of fungi with huge economical, biotechnological, and social significance. Taxonomically, is divided into six subgenera comprising 27 sections. In this study, 235 strains of subgenus (section: , , , , and ) preserved at the Korean Agricultural Culture Collection (KACC) were analyzed and re-identified using a combined dataset of partial β-tubulin (), Calmodulin () gene sequences and morphological data. We confirmed nineteen species to be priorly reported in Korea (, , , , , , , , , , , , , , , , , , and ). Among the studied strains, three species (, , and ), previously unreported or not officially documented, were discovered in Korea, to the best of our knowledge. We have given a detailed description of the characteristic features of the three species, which remain uncharted in Korea.
PubMed: 37929011
DOI: 10.1080/12298093.2023.2257997 -
Foods (Basel, Switzerland) Oct 2023and are important pathogenic fungi that pose a serious threat because of their ability to produce mycotoxins, including ochratoxin A (OTA) and aflatoxins (AFs). The...
and are important pathogenic fungi that pose a serious threat because of their ability to produce mycotoxins, including ochratoxin A (OTA) and aflatoxins (AFs). The main method of reducing these pathogens is the use of chemical fungicides, though recently there has been a focus on finding biological control agents. The obtained results from this study indicate the great potential of two wild yeast strains, PP3 and D10, in the biological control of and and reductions in the amount of OTA and AFs they produce. In vitro, the growth of the mycelium of pathogens was reduced by 41.21% to 53.64%, and spore germination was inhibited by 58.39% to 71.22%. Both yeast strains produced the enzymes chitinase, β-1,3-glucanase, and amylase, and PP3 additionally produced protease and cellulase. This yeast strain also had the ability to grow over a wide range of temperature (4-30 °C), salinity (0-12%) and pH (4-11) conditions. No growth of the yeast was observed at 37 °C, nor any biogenic amines or hydrogen sulfide production. Adding the tested yeast inoculum to the dough reduced OTA (within 14.55-21.80%) and AFs (within 18.10-25.02%) in the model bread.
PubMed: 37893764
DOI: 10.3390/foods12203871