Isolation and Characterization of Sexual Spore Pigments from
            <i>Aspergillus nidulans</i>

Brown, Daren W.; Salvo, Joseph J.

doi:10.1128/aem.60.3.979-983.1994

Cited by 49 publications

(21 citation statements)

References 39 publications

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“…Sexual spores are the product of meiosis and essential for genetic recombination and species diversity and, in several species, are also airborne spores that would be exposed to UV radiation similarly to asexual spores [ 122 , 123 ]. Both trypacidin and endocrocin are produced in the asexual spore [ 75 , 86 ] and our studies (Palmer and Keller, unpublished data)—supported by an earlier investigation [ 124 ]—suggest that asperthecin is the red pigment characterizing the color of A. nidulans sexual ascospores. Assessment of spore viability of NR-PKS fungal mutants under UV conditions might shed light on a conserved role of these molecules to protect from specific abiotic stresses.…”

Section: Discussionsupporting

confidence: 84%

Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

Throckmorton

Wiemann

Keller

2015

Toxins

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Fungal polyketides are a diverse class of natural products, or secondary metabolites (SMs), with a wide range of bioactivities often associated with toxicity. Here, we focus on a group of non-reducing polyketide synthases (NR-PKSs) in the fungal phylum Ascomycota that lack a thioesterase domain for product release, group V. Although widespread in ascomycete taxa, this group of NR-PKSs is notably absent in the mycotoxigenic genus Fusarium and, surprisingly, found in genera not known for their secondary metabolite production (e.g., the mycorrhizal genus Oidiodendron, the powdery mildew genus Blumeria, and the causative agent of white-nose syndrome in bats, Pseudogymnoascus destructans). This group of NR-PKSs, in association with the other enzymes encoded by their gene clusters, produces a variety of different chemical classes including naphthacenediones, anthraquinones, benzophenones, grisandienes, and diphenyl ethers. We discuss the modification of and transitions between these chemical classes, the requisite enzymes, and the evolution of the SM gene clusters that encode them. Integrating this information, we predict the likely products of related but uncharacterized SM clusters, and we speculate upon the utility of these classes of SMs as virulence factors or chemical defenses to various plant, animal, and insect pathogens, as well as mutualistic fungi.

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Section: Discussionsupporting

confidence: 84%

Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

Throckmorton

Wiemann

Keller

2015

Toxins

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“…The hypothesis that fungal 'lignin' was involved is supported by our finding that fungalwall compoimds did accumulate substantially in standing-decaying sedge leaves (Table 4). Fungal-wall melanins (dark-brown phenolic polymers; see references in Brown & Salvo, 1994) would be expected to be at least equally as resistant to decay as the polymers built of the monomers of Table 4 (Newell, 1993a), and both of the fungal species that we observed on C. walteriana (see above) are dark-brown pigmented. Also, LC alteration (lysis/repolymerization?)…”

Section: Discussionmentioning

confidence: 85%

Productivities of microbial decomposers during early stages of decomposition of leaves of a freshwater sedge

et al. 1995

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1. We examined standing-senescing, standing-dead and recently fallen leaf blades of Carex walteriana in fens of the Okefenokee Swamp to determine the nature of the microbial decomposers in the early stages of decomposition, measuring both standing crops and productivities ([^H]leucine->protein method for bacteria, [^^C]acetate-^ergosterol for fungi). 2. Fungal standing crops (ergosterol) became detectable at the mid-senescence stage (leaves about half yellow-brown) and rose to 14-31 mg living-fungal C g"^ organic mass of the decaying system; bacterial standing crops (direct nucroscopy) were =s 0.2 mgC g"' imtil the fallen-leaf stage, when they rose to as high as 0.9 mgC g"^.3. Potential microbial specific growth rates were similar between fungi and bacteria, at about 0.03-0.06 day"', but potential production of fungal mass was 115-512 )j.gC g"ô rganic mass day-\ compared with 0-22 ^gC g'^ day-^ for bacteria. Rates of fungal production were about 6-foId lower on average than previously found for a saltmarsh grass, perhaps because much lower phosphorus concentrations in the freshwater fen limit fungal activity. 4. There was little change in lignocellulose (LC) percentage of decaying leaves, although net loss of organic mass at the fallen, broken stage was estimated to be 59%, suggesting that LC was lost at rates proportional to those for total organics during decay. Monomers of fungal-wall polymers (glucosamine and mannose) accumulated 2-to 4-fold during leaf decay. This may indicate that an increase found for proximate (aciddetergent) lignin could be at least partially due to accumulation of refractory fungal-wall material, including melanin. 5. A common sequence in decaying aquatic grasses is suggested: principally fungal alteration of LC during standing decay, followed by a trend toward bacterial decomposition of the LC after leaves fall and break into particles.

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“…Aflatoxins are produced also via the polyketide synthase pathway. The first stable intermediate in the aflatoxin biosynthesis pathway, norsolorinic acid, has a very similar structure to the pigments of A. flavus spores [24], suggesting that the aflatoxin and melanin biosynthetic pathways have common initial stages.…”

Section: Discussionmentioning

confidence: 99%

p-Cymene and its derivatives exhibit antiaflatoxigenic activities against Aspergillus flavus through multiple modes of action

et al. 2018

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Three monoterpenes, 1-methyl-4-(1-methylethyl)-benzene, and its derivatives, carvacrol and thymol, were tested for their antifungal and antiaflatoxigenic activities against Aspergillus flavus, and their potential in vitro mechanisms were evaluated. The monoterpenes significantly inhibited mycelial growth, spore production, and aflatoxin production in a dose-dependent manner. Furthermore, their antifungal effects were related to the suppression of fungal development regulatory genes (brlA, abaA, and wetA) and inhibition of ergosterol synthesis. Additionally, the down-regulation of the relative expression of genes related to aflatoxin biosynthesis (aflD, aflK, aflQ, and aflR) revealed an antiaflatoxigenic mechanism of the monoterpenes. These observations suggest that the three monoterpenes exhibit antiaflatoxigenic activities through multiple modes of action and may be useful for controlling aflatoxin contamination in food.

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Isolation and Characterization of Sexual Spore Pigments from Aspergillus nidulans

Cited by 49 publications

References 39 publications

Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

Productivities of microbial decomposers during early stages of decomposition of leaves of a freshwater sedge

p-Cymene and its derivatives exhibit antiaflatoxigenic activities against Aspergillus flavus through multiple modes of action

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