Search Results (64)

Melanin is a complex natural pigment that imparts a variety of colors to the fruiting bodies of edible fungi, influencing both their nutritional quality and commercial value. Stropharia rugosoannulata is an emerging type of edible fungus that has been widely cultivated in recent years. It can be categorized into red and yellow varieties based on cap color, while its pigment characteristics remain unclear. In this study, the melanins from the two varieties were obtained using an alkaline extraction and acid precipitation method, followed by comprehensive characterization of their chemical properties and ultrastructural features. Both melanins displayed distinct absorption maxima at approximately 211 nm. The melanin extracted from the red variety consisted of 55.63% carbon (C), 7.40% hydrogen (H), 30.23% oxygen (O), 5.99% nitrogen (N), and 0.64% sulfur (S), whereas the yellow variety comprised 52.22% C, 6.74% H, 29.70% O, 5.91% N, and 0.99% S. Both types of melanin included eumelanin and phaeomelanin forms, with eumelanin being the predominant type. Variations in the quantities and relative proportions of eumelanin and phaeomelanin contributed to the observed color differences in the mushroom caps. Ultrastructural micrographs revealed the melanins were primarily localized in the cell wall, consistent with findings in other fungal species. These findings contribute valuable insights into fundamental knowledge and potential applications of mushroom pigments. Full article

Oxidative stress and its relation to the onset of several chronic diseases have been increasingly highlighted in recent years. In parallel, there has been an increasing interest in the antioxidant properties of phytochemicals. Phytochemicals are products of plant secondary metabolism, including structural polysaccharides, unsaturated fatty acids, pigments (chlorophylls, carotenoids, and anthocyanins), or phenolic compounds. Phytochemicals can be obtained from lower and higher plants, their fruits, and even from macro- or microalgae. Their diverse structural features are linked to different beneficial effects through various molecular mechanisms, contributing to disease prevention. Beyond antioxidant activity, many phytochemicals also display anti-inflammatory, antidiabetic, anti-obesity, and neuroprotective effects, which can be intertwined. Beyond these, other natural antioxidants can also be obtained from animal, fungal, and bacterial sources. Thus, a wide range of antioxidants have the potential to be used as nutraceuticals with chemopreventive effects on the onset of various diseases related to antioxidant stress. Given their enormous structural and sourcing diversity, the present work provides an updated insight into the therapeutic and preventive potential of plant-derived antioxidants and nutraceuticals. Full article

The management of Dollar spot, the fungal disease of turfgrasses, is complicated and, today, tends to include new eco-friendly approaches. The aim of this study is to evaluate the effect of UV-B and UV-C lamps against the infection of Clarireedia species in warm- and cool-season turfgrasses. In vitro tests were performed to evaluate the growth of C. jacksonii mycelium on Potato Dextrose Agar, irradiated with UV-B and UV-C at heights of 5 and 15 cm, 5 s per day for three consecutive days. The same treatments, prolonged for seven days, were applied on naturally infected potted Agrostis stolonifera and Cynodon dactylon × C. transvaalensis, for in vivo tests. Disease severity, antioxidant capacity, and pigment content were assessed at the end of the experiment. Only UV-C reduced the growth of C. jacksonii after 48 h at 5 cm (−36%) and 72 h at both distances (−15 and −27%). Agrostis stolonifera showed symptoms, reduced by UV-C at 5 cm, and fungal structures, except in UV-C exposed samples. Total antioxidant capacity increased after UV-B exposure at 5 cm (+10%). No variations in terms of photosynthetic pigments were observed. These results confirm the potential of UV-C lamps for the containment of Dollar spot. Full article

Tattoos have been a ubiquitous phenomenon throughout history. Now, the demand for tattoo removal for aesthetic or practical reasons is growing rapidly. This study outlines the results of field investigations into the chemical and biological removal of tattoo inks (Hexadecachlorinate copper phthalocyanine—C₃₂Cl₁₆CuN₈—CAS no° 1328-53-6). FTIR, Py-GC/MS, and NMR analyses yielded intriguing profiles pertaining to the primary chemical constituents, along with others of an ambiguous nature. A bioremoval protocol was developed on a pork rind surface to simulate human tattooing. Two previously studied microbial strains were included in this analysis: (i) a bacterial culture of Pseudomonas stutzeri 5190 DSMZ viable cells and (ii) a fungal culture of Alternaria infectoria strain NIS4, the latter already isolated and identified. A combination of physical, chemical, and microbiological analyses, along with microscopic observations, was conducted. In our experimental conditions, inocula from environmental samples (soil and compost) were capable of inducing changes in even trace organic matter (glycerin and additives in pigments) used as a binder in emulsifiers in tattoo inks. Furthermore, the two microbial strains demonstrated promising potential for removing green tattoo ink. Finally, wastewater effluents containing green ink were recovered via electrochemical treatment, and the environmental impact in terms of the CO₂ equivalent of our experiments was assessed. The results are promising and warrant further investigation into the innovative biological and chemical removal of tattoo inks from human skin and wastewater, respectively. Full article

This review explores the production of the fungal polysaccharide pullulan by mutants and natural isolates of Aureobasidium species using strain improvement. Pullulan is a neutral polysaccharide gum whose structure is a maltotriose-containing glucan. This polysaccharide gum has applications in the fields of food, pharmaceuticals, biomedical and wastewater treatment. The strain improvement of Aureobasidium species has focused on the pullulan production process, including the isolation of strains exhibiting reduced pigmentation, polysaccharide overproduction, the production of pullulan with variable molecular weight, and increased osmotolerant strains promoting pullulan production at high carbon source concentrations and pullulan production on hemicellulosic substrates. The majority of studies have emphasized the isolation of reduced pigmentation and pullulan hyperproducer strains since the goal of large-scale commercial pullulan production is to synthesize non-pigmented polysaccharides. A promising area of strain improvement is the isolation of strains that synthesize authentic pullulan from hemicellulosic substrates. If strain improvement in this area is successful, the goal of commercially producing pullulan at a competitive cost will eventually be achieved. Full article

In a survey of mycoviruses in Fusarium species that cause sugarcane Pokkah boeng disease, twelve Fusarium strains from three Fusarium species (F. sacchari, F. andiyazi, and F. solani) were found to contain Fusarium sacchari hypovirus 1 (FsHV1), which we reported previously. The genomes of these variants range from 13,966 to 13,983 nucleotides, with 98.6% to 99.9% nucleotide sequence identity and 98.70% to 99.9% protein sequence similarity. Phylogenetic analysis placed these FsHV1 variants within the Alphahypovirus cluster of Hypoviridae. Intriguingly, no clear correlation was found between the geographic origin and host specificity of these viral variants. Additionally, six out of the twelve variants displayed segmental deletions of 1.5 to 1.8 kilobases, suggesting the existence of defective viral dsRNA. The presence of defective viral dsRNA led to a two-thirds reduction in the dsRNA of the wild-type viral genome, yet a tenfold increase in the total viral dsRNA content. To standardize virulence across natural strains, all FsHV1 strains were transferred into a single, virus-free Fusarium recipient strain, FZ06-VF, via mycelial fusion. Strains of Fusarium carrying FsHV1 exhibited suppressed pigment synthesis, diminished microspore production, and a marked decrease in virulence. Inoculation tests revealed varying capacities among different FsHV1 variants to modulate fungal virulence, with the strain harboring the FsHV1-FSA1 showing the lowest virulence, with a disease severity index (DSI) of 3.33, and the FsHV1-FS1 the highest (DSI = 17.66). The identification of highly virulent FsHV1 variants holds promise for the development of biocontrol agents for Pokkah boeng management. Full article

Biofinish is an innovative wood protection system inspired by biological processes. It enhances the hydrophobicity of wood through oil treatment, resulting in improved dimensional stability. Living cells of the fungus Aureobasidium pullulans effectively protect wood from deterioration caused by other decaying fungi. The melanin pigment produced by the fungus provides an appealing dark surface and additionally protects the wood substrate against UV radiation. The significant advantage of Biofinish is its remarkable self-healing ability, which distinguishes it from conventional wood protection methods. This research aimed to explore fungal species colonising surfaces exposed to natural weathering and assess the survival of A. pullulans on wood surfaces coated with Biofinish during its in-service period. This study was performed on a facade composed of European larch wood (Larix decidua) treated with linseed oil and coated with Biofinish at the InnoRenew CoE building in Izola, Slovenia, following a 9-month exposure period. The majority of the detected species belonged to the genera Aureobasidium. The results indicated the survival and effective antagonistic action of A. pullulans, the living and active ingredient of the coating, against other wood-decaying fungi. Full article

Terpenes and their derivatives comprise a diverse group of natural compounds with versatile medicinal properties. This article elucidates the general characteristics of fungal terpenes and terpenoids, encompassing their structure and biogenesis. The focal point of this work involves a comprehensive overview of these compounds, highlighting their therapeutic properties, mechanisms of action, and potential applications in treating specific skin conditions. Numerous isolated terpenes and terpenoids have demonstrated noteworthy anti-inflammatory and anti-microbial effects, rivalling or surpassing the efficacy of currently employed treatments for inflammation or skin infections. Due to their well-documented antioxidant and anti-cancer attributes, these compounds exhibit promise in both preventing and treating skin cancer. Terpenes and terpenoids sourced from fungi display the capability to inhibit tyrosinase, suggesting potential applications in addressing skin pigmentation disorders and cancers linked to melanogenesis dysfunctions. This paper further disseminates the findings of clinical and in vivo research on fungal terpenes and terpenoids conducted thus far. Full article

Seaweeds have been explored as a natural resource of compounds of interest due to their bioactivities. Although many studies report the interest and the application of seaweeds in various areas, from food or human health to the economy, these data mostly focus on raw extracts and not on specific compounds, such as seaweed pigments. Fungal infections of the skin, nails, and hair caused by dermatophytes are the most common fungal infections worldwide. These pathologies require long periods of topical and/or systemic treatment associated with adverse effects and increased antifungal resistance. So, this study had two objectives: the first was to isolate and characterize the pigments of the seaweeds Calliblepharis jubata and Fucus vesiculosus; the second was to assess their antifungal activity. The extraction of pigments was performed using a method of extraction by exhaustion, and the purification was achieved via column chromatography. Three techniques were used to characterize the pigments: thin-layer chromatography (TLC), UV–visible spectrophotometry, and Fourier-transform infrared spectroscopy (FTIR). The antifungal activity against the three most common dermatophytes, Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum canis, was evaluated using a microdilution methodology, following the EUCAST international standards. It was possible to observe that the extracts obtained from the seaweed C. jubata, corresponding to the purified pigment phycobiliprotein, and the crude extract (an enriched extract) showed antifungal activity against the three fungal agents of human skin infection. Full article

Pigments of fungal origin have aroused increasing interest in the food dye and cosmetic industries since the global demand for natural dyes has grown. Endophytic microorganisms are a source of bioactive compounds, and Amazonian plant species can harbor fungi with a wide range of biotechnological applications. Popularly known in Brazil as crajiru, Fridericia chica is a medicinal plant that produces a red pigment. In this study, a total of 121 fungi were isolated in potato dextrose agar from three plants. We identified nine pigment-producing endophytic fungi isolated from branches and leaves of F. chica. The isolates that showed pigment production in solid media were molecularly identified via multilocus analysis as Aspergillus welwitschiae, A. sydowii, Curvularia sp., Diaporthe cerradensis (two strains), Hypoxylon investiens, Neoscytalidium sp. (two strains) and Penicillium rubens. These isolates were subjected to submerged fermentation in two culture media to obtain metabolic extracts. The extracts obtained were analyzed in terms of their absorbance between 400 and 700 nm. The pigmented extract produced by H. investiens in medium containing yeast extract showed maximum absorbance in the red absorption range (UA₇₀₀ = 0.550) and significant antioxidant and antimicrobial activity. This isolate can thus be considered a new source of extracellular pigment. Full article

Constant monitoring is necessary for powdery mildew prevention in field crops because, as a fungal disease, it modifies the green pigments of the leaves and is responsible for production losses. Therefore, there is a need for solutions that assure early disease detection to realize proactive control and management of the disease. The methodology currently used for the identification of powdery mildew disease uses RGB leaf images to detect damage levels. In the early stage of the disease, no symptoms are visible, but this is a point at which the disease can be controlled before the symptoms appear. This study proposes the implementation of a support vector machine to identify powdery mildew on cucurbit plants using RGB images and color transformations. First, we use an image dataset that provides photos covering five growing seasons in different locations and under natural light conditions. Twenty-two texture descriptors using the gray-level co-occurrence matrix result are calculated as the main features. The proposed damage levels are ’healthy leaves’, ’leaves in the fungal germination phase’, ’leaves with first symptoms’, and ’diseased leaves’. The implementation reveals that the accuracy in the L * a * b color space is higher than that when using the combined components, with an accuracy value of 94% and kappa Cohen of 0.7638. Full article

Villosiclava virens (anamorph: Ustilaginoidea virens) is the pathogen of rice false smut (RFS), which is a destructive rice fungal disease. The albino strain LN02 is a natural white-phenotype mutant of V. virens due to its incapability to produce toxic ustilaginoidins. In this study, three strains including the normal strain P1, albino strain LN02, and complemented strain uvpks1^C-1 of the LN02 strain were employed to investigate the activation of the ustilaginoidin biosynthesis gene uvpks1 in the albino strain LN02 to influence sporulation, conidia germination, pigment production, stress responses, and the inhibition of rice seed germination. The activation of the ustilaginoidin biosynthesis gene uvpks1 increased fungal tolerances to NaCl-induced osmotic stress, Congo-red-induced cell wall stress, SDS-induced cell membrane stress, and H₂O₂-induced oxidative stress. The activation of uvpks1 also increased sporulation, conidia germination, pigment production, and the inhibition of rice seed germination. In addition, the activation of uvpks1 was able to increase the mycelial growth of the V. virens albino strain LN02 at 23 °C and a pH from 5.5 to 7.5. The findings help in understanding the effects of the activation of uvpks1 in albino strain LN02 on development, pigment production, stress responses, and the inhibition of rice seed germination by controlling ustilaginoidin biosynthesis. Full article

Metarhizium robertsii microsclerotia are fungal aggregates composed of compacted, pigmented hyphae. As they are highly tolerant to desiccation and produce infective conidia, they are promising candidates to be formulated as bioinsecticides. Despite this potential, the nature of the pigments within these structures remains unclear. In this study, routine culture media used for the differentiation of M. robertsii microsclerotia were supplemented with four melanin inhibitors, and the resulting propagules were characterized. Inhibitors of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthetic pathway such as tricyclazole and guaiacol induced significant phenotypic and molecular modifications in the obtained M. robertsii propagules, which exhibited a more spherical shape, reduced size, and increased susceptibility to desiccation, heat, and oxidative stress than microsclerotia obtained without inhibitors. Additionally, genes encoding for a polyketide synthase (Mrpks2) and a putative 1,3,6,8-tetrahydroxynaphthalene reductase (Mrthnr), potentially involved in the DHN-melanin biosynthetic pathway, were upregulated in fungi grown in the inhibitor-added media. In conclusion, M. robertsii microsclerotia contain melanins of type DHN that might play a role in both microsclerotia differentiation and environmental stress tolerance. Full article

Synthetic dyes are generally not safe for human health or the environment, leading to the continuous search and growing demand for natural pigments that are considered safer, biodegrade more easily, and are environmentally beneficial. Among micro-organisms, fungi represent an emerging source of pigments due to their many benefits; therefore, they are readily viable on an industrial scale. Among all the bioactive pigments produced by fungi, melanin is an enigmatic, multifunctional pigment that has been studied for more than 150 years. This dark pigment, which is produced via the oxidative polymerization of phenolic compounds, has been investigated for its potential to protect life from all kingdoms, including fungi, from biotic and abiotic stresses. Over time, the research on fungal melanin has attracted a significant amount of scientific interest due to melanin’s distinct biological activities and multifarious functionality, which is well-documented in the literature and could possibly be utilized. This review surveys the literature and summarizes the current discourse, presenting an up-to-date account of the research performed on fungal melanin that encompasses its types, the factors influencing its bioactivity, the optimization of fermentation conditions to enhance its sustainable production, its biosynthetic pathways, and its extraction, as well as biochemical characterization techniques and the potential uses of melanin in a wide range of applications in various industries. A massive scope of work remains to circumvent the obstacles to obtaining melanin from fungi and exploring its future prospects in a diverse range of applications. Full article

Colorants have many applications in food, cosmetics, pharmaceutics, textile, paints, plastics, paper, ink and photographic industries. Colorants are classified according to their solubility into dyes and pigments. Those of natural origin have many advantages over synthetic ones, as natural colorants usually do not induce allergies or other health problems. In addition, their consumption in the food and drug industries is fortified with nutritional and health benefits as the majority of them possess antioxidant activity or can be used to produce some vitamins. Plants, animals, insects and microorganisms are rich sources of colorants. However, microbial pigments are favored over other natural pigments due to their higher yield, stability, economical production. Therefore, we focus in this review on fungal pigments, the history of their use, their chemistry and their applications in food and non-food fields. Additionally, the ability of the fungal genus, Epicoccum, to produce pigments is discussed. Moreover, the challenges and future prospects concerning fungal pigment production are highlighted in detail. Full article