-
Toxins May 2024Mycotoxins, secondary metabolites synthesized by various filamentous fungi genera such as , , , , and , are potent toxic compounds. Their production is contingent upon... (Review)
Review
Mycotoxins, secondary metabolites synthesized by various filamentous fungi genera such as , , , , and , are potent toxic compounds. Their production is contingent upon specific environmental conditions during fungal growth. Arising as byproducts of fungal metabolic processes, mycotoxins exhibit significant toxicity, posing risks of acute or chronic health complications. Recognized as highly hazardous food contaminants, mycotoxins present a pervasive threat throughout the agricultural and food processing continuum, from plant cultivation to post-harvest stages. The imperative to adhere to principles of good agricultural and industrial practice is underscored to mitigate the risk of mycotoxin contamination in food production. In the domain of food safety, the rapid and efficient detection of mycotoxins holds paramount significance. This paper delineates conventional and commercial methodologies for mycotoxin detection in ensuring food safety, encompassing techniques like liquid chromatography, immunoassays, and test strips, with a significant emphasis on the role of electrochemiluminescence (ECL) biosensors, which are known for their high sensitivity and specificity. These are categorized into antibody-, and aptamer-based, as well as molecular imprinting methods. This paper examines the latest advancements in biosensors for mycotoxin testing, with a particular focus on their amplification strategies and operating mechanisms.
Topics: Mycotoxins; Biosensing Techniques; Food Safety; Food Contamination; Food Microbiology; Humans; Animals
PubMed: 38922144
DOI: 10.3390/toxins16060249 -
Toxins May 2024produces fumonisins, which are mycotoxins inhibiting sphingolipid biosynthesis in humans, animals, and other eukaryotes. Fumonisins are presumed virulence factors of...
produces fumonisins, which are mycotoxins inhibiting sphingolipid biosynthesis in humans, animals, and other eukaryotes. Fumonisins are presumed virulence factors of plant pathogens, but may also play a role in interactions between competing fungi. We observed higher resistance to added fumonisin B (FB) in fumonisin-producing than in nonproducing , and likewise between isolates of and differing in production of sphinganine-analog toxins. It has been reported that in , ceramide synthase encoded in the fumonisin biosynthetic gene cluster is responsible for self-resistance. We reinvestigated the role of and by generating a double mutant strain in a background. Nearly unchanged resistance to added FB was observed compared to the parental strain. A recently developed fumonisin-sensitive baker's yeast strain allowed for the testing of candidate ceramide synthases by heterologous expression. The overexpression of the yeast gene, but not , increased fumonisin resistance. High-level resistance was conferred by , but not by . Likewise, strong resistance to FB was caused by overexpression of the presumed "housekeeping" ceramide synthases , , and , located outside the fumonisin cluster, indicating that possesses a redundant set of insensitive targets as a self-resistance mechanism.
Topics: Fumonisins; Fusarium; Oxidoreductases; Drug Resistance, Fungal; Fungal Proteins; Aspergillus; Alternaria
PubMed: 38922130
DOI: 10.3390/toxins16060235 -
Journal of Fungi (Basel, Switzerland) Jun 2024, as a main decay fungus of goji berry, can produce mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). Carvacrol (CVR)...
, as a main decay fungus of goji berry, can produce mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). Carvacrol (CVR) has exhibited a broad-spectrum antifungal activity in vitro. We assumed that CVR can also be applied to control rot on goji berries and mycotoxins produced by the pathogens. To investigate whether CVR impacts the accumulation of mycotoxins and cell membrane damage of , the antifungal activity of CVR on the fungal growth and mycotoxin production was evaluated in this study. The results showed that the minimum inhibitory concentration (MIC) of CVR against was 0.12 µL/mL. Meanwhile, the destruction of plasma membrane integrity, cytoplasmic leakage, intracellular oxidative damage, and inhibitory effect in vivo were also observed in treated with CVR. Moreover, CVR significantly reduced the accumulation of AOH, AME, and TeA. Transcriptomic profiling was performed by means of comparative RNA-Seq analysis to research the gene expression level of , which attested to significant changes in nitrogen metabolism, carbon utilization, fatty acid oxidation, and antioxidant enzymes in CVR-treated . This study suggests a new understanding of the molecular mechanism of response to CVR treatment in , indicating that CVR is a novel antifungal agent with the potential to be applied to various fungi.
PubMed: 38921388
DOI: 10.3390/jof10060402 -
Plant Physiology and Biochemistry : PPB Jun 2024The importance of metacaspases in programmed cell death and tissue differentiation is known, but their significance in disease stress response, particularly in a crop...
The importance of metacaspases in programmed cell death and tissue differentiation is known, but their significance in disease stress response, particularly in a crop plant, remained enigmatic. We show the tomato metacaspase expression landscape undergoes differential reprogramming during biotrophic and necrotrophic modes of pathogenesis; also, the metacaspase activity dynamics correlate with the disease progression. These stresses have contrasting effects on the expression pattern of SlMC8, a Type II metacaspase, indicating that SlMC8 is crucial for stress response. In accordance, selected biotic stress-related transcription factors repress SlMC8 promoter activity. Interestingly, SlMC8 exhibits maximum proteolysis at an acidic pH range of 5-6. Molecular dynamics simulation identified the low pH-driven protonation event of Glu246 as critical to stabilize the interaction of SlMC8 with its substrate. Mutagenesis of Glu246 to charge-neutral glutamine suppressed SlMC8's proteolytic activity, corroborating the importance of the amino acid in SlMC8 activation. The glutamic acid residue is found in an equivalent position in metacaspases having acidic pH dependence. SlMC8 overexpression leads to heightened ROS levels, cell death, and tolerance to PstDC3000, and SlMC8 repression reversed the phenomena. However, the overexpression of SlMC8 increases tomato susceptibility to necrotrophic Alternaria solani. We propose that SlMC8 activation due to concurrent changes in cellular pH during infection contributes to the basal resistance of the plant by promoting cell death at the site of infection, and the low pH dependence acts as a guard against unwarranted cell death. Our study confirms the essentiality of a low pH-driven Type II metacaspase in tomato biotic stress-response regulation.
PubMed: 38917737
DOI: 10.1016/j.plaphy.2024.108850 -
International Journal of Food... May 2024Alternaria alternata is part of a genus comprised of over 600 different species that occur all over the world and cause damage to humans, plants and thereby to the...
Alternaria alternata is part of a genus comprised of over 600 different species that occur all over the world and cause damage to humans, plants and thereby to the economy. Yet, even though some species are causing tremendous issues, the past years have shown that assigning newly found isolates to known species was rather inconsistent. Most identifications are usually done on the basis of spore morphology, chemotype and molecular markers. In this work we used strains isolated from the wild as well as commercial strains of the DSMZ (German collection of microorganisms and cell cultures) as a reference, to show, that the variation within the Alternaria alternata species is comparable to the variation between different species of the genus Alternaria in regards to spore morphology and chemotype. We compared the different methods of identification and discerned the concatenation of multiple molecular markers as the deciding factor for better identification. Up until this point, usually a concatenation of two or three traditional molecular markers was used. Some of those markers being stronger some weaker. We show that the concatenation of five molecular markers improves the likeliness of a correct assignment, thus a better distinction between the different Alternaria species.
PubMed: 38917488
DOI: 10.1016/j.ijfoodmicro.2024.110746 -
Plant Disease Jun 2024The Chinese quince (Chaenomeles sinensis (Thouin) Koehne), belongs to the Rosaceae family, is widely distributed throughout Asia, including Republic of Korea. It is used...
The Chinese quince (Chaenomeles sinensis (Thouin) Koehne), belongs to the Rosaceae family, is widely distributed throughout Asia, including Republic of Korea. It is used as a traditional treatment for asthma, common cold, and dry pharynx. Numerous recent pharmacological studies on antiinfluenza, antioxidant, and antidiabetic properties have confirmed the medicinal properties of the Chinese quince fruit (Chun et al., 2012). In March 2022, leaf spots on Chinese quince, resulting in defoliation, were observed in Andong, Gyeongsangbuk Province, Korea (Fig. 1A). The disease symptoms are dark brown spots on leaves. Later, the chlorophyll is lost, causing the entire leaf to become wilted and fell off (Fig. 1B). To identify the pathogen, symptomatic leaves were brought to the laboratory, cut into small pieces, and surface-disinfected in 70% ethanol for 15 s and rinsed with sterile distilled water (SDW). The specimens were then treated with 1% NaOCl for 15 s, followed by rinsing with SDW. Thus, surface-disinfected tissues were placed onto potato dextrose agar (PDA) plates and incubated at 25°C for 7 d. A total of four isolates were obtained from the infected leaves. The colonies were transferred onto freshly prepared PDA plates by the single spore method for further purification. GYUN-10746 isolate was selected as the representative strain among the four isolates and deposited in the Korean Agricultural Culture Collection (KACC 410367). They initially produced white mycelia, which turned dark brown or pale brown at the center and beige at the periphery after 7 d (Fig. 1C and D). Conidiophores were pyriform, sometimes ovoid, or ellipsoidal and brown, measuring 30.8 ± 0.49 × 12.9 ± 0.26 µm (length × width) (n=100) (Fig. 1E). The morphological characteristics were consistent with those of Alternaria alternata (Woudenberg et al. 2015). For molecular identification, DNA was amplified using the following primers: ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone et al. 1999), Gpd-R/Gpd-F (Berbee et al. 1999), Alt a1-F/Alt a1-R (Hong et al. 2005) and rpb2F/rpb2R (Liu et al. 1999) by PCR. DNA sequences from all 4 isolates (GYUN-10746, GYUN-11193, GYUN-11194 and GYUN-11195) were identical. The ITS (OP594615), TEF1-α (OR327062), GAPDH (OR372157), Alt a 1 (OR327061), and RPB2 (OR352741) sequences from the representative isolate GYUN-10746 were 100% identical to those of previously identified A. alternate isolates. A phylogenetic tree was constructed using sequences of ITS, TEF1-α, GAPDH, Alt a l, and RPB2 to illustrate their relationship with A. alternata and related Alternaria species (Fig. 2). For the pathogenicity test, healthy Chinese quince branch containing leaves were inoculated with 7-day-old mycelial plugs of A. alternata, while leaves on a branch inoculated with PDA plugs alone served as a control group. Thus inoculated branches were incubated at 25°C for 7 d. Disease symptoms were developed on leaves of the branches inoculated with mycelial plugs of the fungal pathogen (Fig. 1F), while no symptoms developed on control group. The resulting leaf spots resembled those on the original infected plants. To confirm Koch's postulates, the pathogen was re-isolated from inoculated leaves with identical morphological and molecular characteristics. To the best of our knowledge, this is the first report of leaf spot caused by A. alternata in C. sinensis in Korea. The identification of the pathogen may provide pertinent information for the development of disease controlling strategies.
PubMed: 38916907
DOI: 10.1094/PDIS-05-24-0984-PDN -
BioRxiv : the Preprint Server For... Jun 2024Vagal sensory neurons convey sensations from internal organs along the vagus nerve to the brainstem. Pruriceptors are a subtype of neurons that transmit itch and induce...
Vagal sensory neurons convey sensations from internal organs along the vagus nerve to the brainstem. Pruriceptors are a subtype of neurons that transmit itch and induce pruritus. Despite extensive research on the molecular mechanisms of itch, studies focusing on pruriceptors in the vagal ganglia still need to be explored. In this study, we characterized vagal pruriceptor neurons by their responsiveness to pruritogens such as lysophosphatidic acid, -alanine, chloroquine, and the cytokine oncostatin M. We discovered that lung-resident basophils produce oncostatin M and that its release can be induced by engagement of FcRI. Oncostatin M then sensitizes multiple populations of vagal sensory neurons, including Tac1 and MrgprA3 neurons in the jugular ganglia. Finally, we observed an increase in oncostatin M release in mice sensitized to the house dust mite or to the fungal allergen , highlighting a novel mechanism through which basophils and vagal sensory neurons may communicate during type I hypersensitivity diseases such as allergic asthma.
PubMed: 38915548
DOI: 10.1101/2024.06.11.598517 -
Food Additives & Contaminants. Part A,... Jun 2024Mycotoxins are secondary fungal metabolites harmful to humans and animals. Patulin (PAT) is a toxin found in different food products but especially in apples and their...
Mycotoxins are secondary fungal metabolites harmful to humans and animals. Patulin (PAT) is a toxin found in different food products but especially in apples and their derivative products. The most common fungi producers of this compound are and The production of patulin, as other mycotoxins, can be impacted by diverse phenomena such as water and nutrient availability, UV exposure, and the presence of antagonistic organisms. Consequently, gaining a comprehensive understanding of climate and environmental conditions is a crucial step in combating patulin contamination. In this study, moulds were isolated from 40 apple samples collected from seven locations across Hungary: Csenger, Damak, Pallag, Lövőpetri, Nagykálló, and Újfehértó. A total of 183 moulds were morphologically identified, with 67 isolates belonging to the , 45 to the , and 13 to the groups. The location possessed a higher influence than farming method on the distribution of mould genera. Despite the requirement of higher temperature, species dominated only for the region of Újfehértó with approximately 50% of the isolates belonging to the genus. Four of the seven locations assessed: Csenger, Debrecen-Pallag, Nyírtass and Nagykálló, were dominated by species. All isolates belonging to the genera and were tested for the presence of the isoepoxidone dehydrogenase () gene, a key player in the patulin metabolic pathway. To guarantee patulin production, this ability was confirmed with TLC assays. The only strain that presented a positive result was the strain B9/6, originated from the apple cultivar Golden Reinders grown in Debrecen-Pallag by integrated farming. Of the isolates only one strain, B10/6, presented a band of the right size (500-600 bp) for the gene. Further sequencing of the ITS gene showed that this strain should be classified as The TLC tests confirmed this microorganism as the only patulin producer under the studied conditions for its cluster.
PubMed: 38913828
DOI: 10.1080/19440049.2024.2364364 -
Microbiology Spectrum Jun 2024Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in as contributors to the virulence of . Here, we constructed and deletion mutants in...
UNLABELLED
Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in as contributors to the virulence of . Here, we constructed and deletion mutants in strain HWC168 to further reveal the effects of these genes on the biology and pathogenicity of . Deletion of and did not affect vegetative growth but did affect conidial maturation, with an increase in the percentage of abnormal conidia produced. Furthermore, we determined the expression patterns of genes involved in the conidiogenesis pathway and found that the regulatory gene was significantly upregulated and , a positive regulator for conidiation, was significantly downregulated in the mutant strains compared to the wild-type strain. These results suggest that AsCEP19 and AsCEP20 indirectly affect the conidial development and maturation of . Pathogenicity assays revealed significantly impaired virulence of Δ, Δ and Δ mutants on potato and tomato plants. Moreover, we performed localization assays with green fluorescent protein-tagged proteins in chili pepper leaves. We found that AsCEP19 can specifically localize to the chloroplasts of chili pepper epidermal cells, while AsCEP20 can localize to both chloroplasts and the plasma membrane. Weighted gene co-expression network analysis revealed enrichment of genes of this module in the photosynthesis pathway, with many hub genes associated with chloroplast structure and photosynthesis. These results suggest that chloroplasts are the targets for AsCEP19 and AsCEP20.
IMPORTANCE
is an important necrotrophic pathogen causing potato early blight. Previous studies have provide preliminary evidence that specific effectors AsCEP19 and AsCEP20 contribute to virulence, but their respective functions, localization, and pathogenic mechanisms during the infection process of remain unclear. Here, we have systematically studied the specific effectors AsCEP19 and AsCEP20 for the first time, which are essential for conidial maturation. The deletion of AsCEP19 and AsCEP20 can significantly impair fungal pathogenicity. Additionally, we preliminarily revealed that AsCEP19 and AsCEP20 target the chloroplasts of host cells. Our findings further enhance our understanding of the molecular mechanisms underlying the virulence of necrotrophic pathogens.
PubMed: 38912810
DOI: 10.1128/spectrum.04214-23 -
Frontiers in Plant Science 2024[This corrects the article DOI: 10.3389/fpls.2023.1278127.].
[This corrects the article DOI: 10.3389/fpls.2023.1278127.].
PubMed: 38911985
DOI: 10.3389/fpls.2024.1435731