Studies on the biosynthesis of aspergillin by Aspergillus niger.

Abstract

Two inhibitors of the biosynthesis of aspergillin, the black spore pigment of Aspergillus niger, have been investigated. 2,4-Dithiopyrimidine exerted its inhibitory effect by intracellularly chelating cupric ion required for normal pigmentation. Dimethylsulfoxide prevented the synthesis of certain phenolic precursors of the native pigment. Partial purification and characterization of pigments from mature cultures revealed the presence of at least three components: (i) a high-molecular-weight (-20,000) native pigment fraction in untreated mold cultures, (ii) a lower-molecular-weight (-5,000) melanin pigment found in both types of inhibited cultures, and (iii) a low-molecular-weight (368) green pigment found only in the 2,4-dithiopyrimidine-inhibited cultures and proposed to be a pentacyclic quinonoid derivative. A pathway for aspergillin biosynthesis is suggested based on these results.

Higher effectiveness of photoinactivation of bacterial spores, UV resistant vegetative bacteria and mold spores with 222 nm compared to 254 nm wavelength

“…This necessary UV fluence is only slightly higher than in the present investigation for the vegetative bacteria. Also responsible for the high UV resistance of A. niger is the black spore pigment aspergillin which is certainly able to absorb high amounts of the UV radiation to protect the cell [12]. If highly efficient repair mechanisms were responsible for the resistance, the inactivation curve would show a higher shoulder [13].…”

Fungal Pigments and Their Prospects in Different Industries

“…Erythroglaucin (red), physcion (yellow), catenarin (red), rubrocristin (red) [25] Aspergillus fumigatus Melanin (dark brown-black) [25,111] Aspergillus falconensis, Aspergillus fruticulosus Aspergillus nidulans Ascoquinone A (red), norsolorinic acid, sterigmatocystin (yellow), melanin (dark brown-black) [25,112,113] Aspergillus niger Flavioline (orange-red), N-naptho-γ-pyrones (yellow), aspergillin (black), azanigerones A-F, asperenone (yellow), melanin (dark brown-black) [25,61,110,114,115] Aspergillus nishimurae Anishidiol (yellow) [116] Aspergillus parvathecia, Aspergillus rugulosus, Aspergillus versicolor Sterigmatocystin (yellow) [25] Aspergillus purpureus Aspergillus sclerotioniger Uncharacterized (yellow) [61] Aspergillus sclerotiorum Neoaspergillic acid (yellow-green) [91] Aspergillus terreus Uncharacterized (yellow) [118] Aspergillus sp. Ferriaspergillin (red), ferrineoaspergillin (red) [119] Aspergillus sp.…”

“…Several members of the genus Aspergillus, such as Aspergillus niger, have been known to synthesize a wide variety of pigments, such as aspergillin, asperenone, azaphilones (azanigerones A-F), and melanin ( Figure 5a) [25,110,114,115]. Aspergillus nidulans was reported to produce ascoquinone A, norsolorinic acid, and melanin [25,112,113], whereas Aspergillus fumigatus was reported to produce melanin and melanin-like pigments [25,111].…”

Comparative Sensitivity of Trichophyton and Aspergillus Conidia to Inactivation by Violet-Blue Light Exposure

“…The high resistance of A. niger spores to 405 nm light is most likely due to possession of a multilayered pigmented spore coat containing aspergillin, a black coloured melanin-like compound making the spores particularly difficult to inactivate when exposed to visible light 26 and pulsed UV-light 27,28 . The presence of the aspergillin pigment explains why A. niger conidia are more resistant to 405 nm radiation than the conidia of T. rubrum, and indeed to the A. niger hyphae which is non-pigmented.…”