Phenotypic analyses of ΔwcoA and ΔwcoB mutants in Fusarium fujikuroi reveal dark and light-dependent functions as a white-collar complex.

The Fusarium fujikuroi fungus, known as a biotechnological source of gibberellins, has a complex secondary metabolism that responds to various environmental signals, including the availability of light and nitrogen. White collar complex proteins, consisting of the flavoprotein WC1 and its partner WC2, are widespread in fungi where they play a central role in the regulation of numerous genes in response to light. Fusarium fungi possess one copy of each WC gene, named wcoA and wcoB in F.

The RNAi Machinery in the Fungus Is Not Very Active in Synthetic Medium and Is Related to Transposable Elements.

Small RNAS (sRNAs) participate in regulatory RNA interference (RNAi) mechanisms in a wide range of eukaryotic organisms, including fungi. The fungus , a model for the study of secondary metabolism, contains a complete set of genes for RNAi pathways. We have analyzed by high-throughput sequencing the content of sRNAs in total RNA samples of grown in synthetic medium in the dark or after 1 h of illumination, using libraries below 150 nt, covering sRNAs and their precursors.

Three Genes Involved in Different Signaling Pathways, , , and , Participate in the Regulation of Fusarin Biosynthesis in .

The phytopathogenic fungus has a rich secondary metabolism which includes the synthesis of very different metabolites in response to diverse environmental cues, such as light or nitrogen. Here, we focused our attention on fusarins, a class of mycotoxins whose synthesis is downregulated by nitrogen starvation. Previous data showed that mutants of genes involved in carotenoid regulation (, encoding a RING finger protein repressor), light detection (, White Collar photoreceptor), and cAMP signaling (AcyA, adenylate cyclase) affect the synthesis of different metabolites.

Bioavailability and provitamin A activity of neurosporaxanthin in mice.

Various species of ascomycete fungi synthesize the carboxylic carotenoid neurosporaxanthin. The unique chemical structure of this xanthophyll reveals that: (1) Its carboxylic end and shorter length increase the polarity of neurosporaxanthin in comparison to other carotenoids, and (2) it contains an unsubstituted β-ionone ring, conferring the potential to form vitamin A. Previously, neurosporaxanthin production was optimized in Fusarium fujikuroi, which allowed us to characterize its antioxidant properties in in vitro assays.

HmbC, a Protein of the HMG Family, Participates in the Regulation of Carotenoid Biosynthesis in .

In the fungus , carotenoid production is up-regulated by light and down-regulated by the CarS RING finger protein, which modulates the mRNA levels of carotenoid pathway genes ( genes). To identify new potential regulators of genes, we used a biotin-mediated pull-down procedure to detect proteins capable of binding to their promoters. We focused our attention on one of the proteins found in the screening, belonging to the High-Mobility Group (HMG) family that was named HmbC.

Water treatment membranes embedded with a stable and bactericidal nanodiamond material.

Filtration has emerged as a critical technology to reduce waterborne diseases caused by poor water quality. Filtration technology presents key challenges, such as membrane selectivity, permeability and biofouling. Nanomaterials can offer solutions to these challenges by varying the membranes' mechanical and bactericidal properties.

Photoreceptors.

Light is an important modulating signal in fungi. species stand out as research models for their phytopathogenic activity and their complex secondary metabolism. This includes the synthesis of carotenoids, whose induction by light is their best known photoregulated process.

Relation between CarS expression and activation of carotenogenesis by stress in .

a model organism for secondary metabolism in fungi, produces carotenoids, terpenoid pigments with antioxidant activity. Previous results indicate that carotenoid synthesis in is stimulated by light or by different stress conditions and downregulated by a RING finger protein encoded by gene. Here, we have analyzed the effects of three stressors, nitrogen scarcity, heat shock, and oxidative stress.

The lncRNA Is a -Related Regulatory Element with Broad Effects on the Transcriptome.

Carotenoid biosynthesis in the fungus is regulated by environmental factors, with light being the main stimulating signal. The CarS RING-finger protein plays an important role in the downregulation of structural genes of the carotenoid pathway. A recent transcriptomic analysis on the effect of mutation identified a gene for a long non-coding RNA (lncRNA) upstream of , called , the deletion of which results in increased mRNA levels and lack of carotenoid production.

Impact of the White Collar Photoreceptor WcoA on the Transcriptome.

The proteins of the White Collar 1 family (WC) constitute a major class of flavin photoreceptors, widely distributed in fungi, that work in cooperation with a WC 2 protein forming a regulatory complex. The WC complex was investigated in great detail in , a model fungus in photobiology studies, where it controls all its major photoresponses. The fungus , a model system in the production of secondary metabolites, contains a single WC-1 gene called .

Controlled Transcription of Regulator Gene by Tet-on or by a Strong Promoter Confirms Its Role as a Repressor of Carotenoid Biosynthesis in .

Carotenoid biosynthesis is a frequent trait in fungi. In the ascomycete , the synthesis of the carboxylic xanthophyll neurosporaxanthin (NX) is stimulated by light. However, the mutants of the gene, encoding a protein of the RING finger family, accumulate large NX amounts regardless of illumination, indicating the role of CarS as a negative regulator.

Neurosporaxanthin Overproduction by and Evaluation of Its Antioxidant Properties.

Neurosporaxanthin (NX) is a carboxylic carotenoid produced by some filamentous fungi, including species of the genera and . NX biosynthetic genes and their regulation have been thoroughly investigated in , an industrial fungus used for gibberellin production. In this species, carotenoid-overproducing mutants, affected in the regulatory gene , exhibit an upregulated expression of the NX pathway.

Osmotolerance as a determinant of microbial ecology: A study of phylogenetically diverse fungi.

Osmotic stress induced by high solute concentration can prevent fungal metabolism and growth due to alterations in properties of the cytosol, changes in turgor, and the energy required to synthesize and retain compatible solutes. We used germination to quantify tolerance/sensitivity to the osmolyte KCl (0.1-4.

A novel lncRNA as a positive regulator of carotenoid biosynthesis in Fusarium.

The fungi Fusarium oxysporum and Fusarium fujikuroi produce carotenoids, lipophilic terpenoid pigments of biotechnological interest, with xanthophyll neurosporaxanthin as the main end product. Their carotenoid biosynthesis is activated by light and negatively regulated by the RING-finger protein CarS. Global transcriptomic analysis identified in both species a putative 1-kb lncRNA that we call carP, referred to as Fo-carP and Ff-carP in each species, upstream to the gene carS and transcribed from the same DNA strand.

Modulation of Activity of a Carotenoid Pathway Through the Use of the TeT-on Regulatory System: Application in the Fungus Fusarium fujikuroi.

Carotenoids are widespread pigments in photosynthetic species, but they are also found in nonphotosynthetic microorganisms, such as bacteria and fungi. The amenability of fungi to genetic studies have made some fungal species advantageous models in the study of the genetics and biochemistry of carotenoid biosynthesis, while others have been used for biotechnological carotenoid production. The availability of molecular techniques that allow modulating the expression of target genes is a powerful tool in the manipulation of carotenoid synthesis.

Comparative transcriptomic analysis unveils interactions between the regulatory CarS protein and light response in Fusarium.

Background: The orange pigmentation of the agar cultures of many Fusarium species is due to the production of carotenoids, terpenoid pigments whose synthesis is stimulated by light. The genes of the carotenoid pathway and their regulation have been investigated in detail in Fusarium fujikuroi. In this and other Fusarium species, such as F.

HPLC Analysis of Carotenoids in Neurosporaxanthin-Producing Fungi.

The ascomycetous fungi Fusarium fujikuroi and Neurospora crassa are widely used as research models in the study of secondary metabolism and photobiology, respectively. Both fungi exhibit a similar carotenoid pathway, for which all the genes and enzymes have been identified. Under standard laboratory conditions, either F.

A global perspective on carotenoids: Metabolism, biotechnology, and benefits for nutrition and health.

Carotenoids are lipophilic isoprenoid compounds synthesized by all photosynthetic organisms and some non-photosynthetic prokaryotes and fungi. With some notable exceptions, animals (including humans) do not produce carotenoids de novo but take them in their diets. In photosynthetic systems carotenoids are essential for photoprotection against excess light and contribute to light harvesting, but perhaps they are best known for their properties as natural pigments in the yellow to red range.

Carotenoid Biosynthesis in Fusarium.

Many fungi of the genus stand out for the complexity of their secondary metabolism. Individual species may differ in their metabolic capacities, but they usually share the ability to synthesize carotenoids, a family of hydrophobic terpenoid pigments widely distributed in nature. Early studies on carotenoid biosynthesis in have been recently extended in and , well-known biotechnological and phytopathogenic models, respectively.

Transcriptional basis of enhanced photoinduction of carotenoid biosynthesis at low temperature in the fungus Neurospora crassa.

Stimulation by light of carotenoid biosynthesis in the mycelia of the fungus Neurospora crassa starts with transient transcriptional induction of the structural genes of the pathway triggered by the White Collar photoreceptor complex. Most studies on this process were carried out under standard growth conditions, but photoinduced carotenoid accumulation is more efficient if the fungus is incubated at low temperatures, from 6 to 12 °C. We have investigated the transcriptional photoresponse at 8 °C of the genes for proteins that participate in the carotenoid pathway.

Strigolactone biosynthesis is evolutionarily conserved, regulated by phosphate starvation and contributes to resistance against phytopathogenic fungi in a moss, Physcomitrella patens.

In seed plants, strigolactones (SLs) regulate architecture and induce mycorrhizal symbiosis in response to environmental cues. SLs are formed by combined activity of the carotenoid cleavage dioxygenases (CCDs) 7 and 8 from 9-cis-β-carotene, leading to carlactone that is converted by cytochromes P450 (clade 711; MAX1 in Arabidopsis) into various SLs. As Physcomitrella patens possesses CCD7 and CCD8 homologs but lacks MAX1, we investigated if PpCCD7 together with PpCCD8 form carlactone and how deletion of these enzymes influences growth and interactions with the environment.

Carotenoid Cleavage Oxygenases from Microbes and Photosynthetic Organisms: Features and Functions.

Apocarotenoids are carotenoid-derived compounds widespread in all major taxonomic groups, where they play important roles in different physiological processes. In addition, apocarotenoids include compounds with high economic value in food and cosmetics industries. Apocarotenoid biosynthesis starts with the action of carotenoid cleavage dioxygenases (CCDs), a family of non-heme iron enzymes that catalyze the oxidative cleavage of carbon-carbon double bonds in carotenoid backbones through a similar molecular mechanism, generating aldehyde or ketone groups in the cleaving ends.

Expansion of Signal Transduction Pathways in Fungi by Extensive Genome Duplication.

Plants and fungi use light and other signals to regulate development, growth, and metabolism. The fruiting bodies of the fungus Phycomyces blakesleeanus are single cells that react to environmental cues, including light, but the mechanisms are largely unknown [1]. The related fungus Mucor circinelloides is an opportunistic human pathogen that changes its mode of growth upon receipt of signals from the environment to facilitate pathogenesis [2].

Improving cytotoxicity against cancer cells by chemo-photodynamic combined modalities using silver-graphene quantum dots nanocomposites.

The combination of chemotherapy and photodynamic therapy has emerged as a promising strategy for cancer therapy due to its synergistic effects. In this work, PEGylated silver nanoparticles decorated with graphene quantum dots (Ag-GQDs) were tested as a platform to deliver a chemotherapy drug and a photosensitizer, simultaneously, in chemo-photodynamic therapy against HeLa and DU145 cancer cells in vitro. Ag-GQDs have displayed high efficiency in delivering doxorubicin as a model chemotherapy drug to both cancer cells.