RESUMO
The astA gene encoding an alternative sulfate transporter was originally cloned from the genome of the Japanese Aspergillus nidulans isolate as a suppressor of sulfate permease-deficient strains. Expression of the astA gene is under the control of the sulfur metabolite repression system. The encoded protein transports sulfate across the cell membrane. In this study we show that AstA, having orthologs in numerous pathogenic or endophytic fungi, has a second function and, depending on growth conditions, can be translocated into mitochondria. This effect is especially pronounced when an astA-overexpressing strain grows on solid medium at 37 °C. AstA is also recruited to the mitochondria in the presence of mitochondria-affecting compounds such as menadione or antimycin A, which are also detrimental to the growth of the astA-overexpressing strain. Disruption of the Hsp70-Porin1 mitochondrial import system either by methylene blue, an Hsp70 inhibitor, or by deletion of the porin1-encoding gene abolishes AstA translocation into the mitochondria. Furthermore, we observed altered ATP levels and sulfite oxidase activity in the astA-overexpressing strain in a manner dependent on sulfur sources. The presented data indicate that AstA is also involved in the mitochondrial sulfur metabolism in some fungi, and thereby indirectly manages redox potential and energy state.
Assuntos
Trifosfato de Adenosina/metabolismo , Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Proteínas Fúngicas/metabolismo , Mitocôndrias/metabolismo , Sulfito Oxidase/metabolismo , Endocitose , Endófitos/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Modelos Biológicos , Oxirredução , Fenótipo , Filogenia , Enxofre/metabolismoRESUMO
Neutrophils are primary phagocytes of the innate immune system that generate reactive oxygen species (ROS) and mediate host defense. Deficient phagocyte NADPH oxidase (PHOX) function leads to chronic granulomatous disease (CGD) that is characterized by invasive infections, including those by the generally non-pathogenic fungus Aspergillus nidulans The role of neutrophil ROS in this specific host-pathogen interaction remains unclear. Here, we exploit the optical transparency of zebrafish to image the effects of neutrophil ROS on invasive fungal growth and neutrophil behavior in response to Aspergillus nidulans In a wild-type host, A. nidulans germinates rapidly and elicits a robust inflammatory response with efficient fungal clearance. PHOX-deficient larvae have increased susceptibility to invasive A. nidulans infection despite robust neutrophil infiltration. Expression of subunit p22phox (officially known as CYBA), specifically in neutrophils, does not affect fungal germination but instead limits the area of fungal growth and excessive neutrophil inflammation and is sufficient to restore host survival in p22phox-deficient larvae. These findings suggest that neutrophil ROS limits invasive fungal growth and has immunomodulatory activities that contribute to the specific susceptibility of PHOX-deficient hosts to invasive A. nidulans infection.
Assuntos
Aspergilose/imunologia , Aspergillus nidulans/crescimento & desenvolvimento , NADPH Oxidases/metabolismo , Neutrófilos/enzimologia , Animais , Aspergillus nidulans/patogenicidade , Doença Granulomatosa Crônica/enzimologia , Inflamação/enzimologia , Modelos Animais , NADPH Oxidases/deficiência , Espécies Reativas de Oxigênio/metabolismo , Peixe-ZebraRESUMO
Plant-extract mediated nanoparticles synthesis is a viable alternative to chemical reduction techniques. Here, we report the microwave-assisted rapid synthesis of silver and gold nanoparticles by the phytoreducer Stereospermum suaveolens for the first time. The formation of the nascent silver and gold nanoparticles is confirmed by their intense surface plasmon resonance peaks at 431 and 585 nm in UV-visible spectroscopy. The poly phenolic and alcoholic functional groups present in the aqueous root bark extract that performed the bioreduction processes have been detected using Fourier transform infrared spectroscopy. Powder X-ray diffraction and selected area electron diffraction patterns settled face centered cubic crystal structures to both silver and gold nanoparticles with a preferred orientation towards the (111) plane. Transmission electron microscopic analysis proved more or less spherical geometry of the silver and gold nanoparticles with average diameter of 49.77 ± 11.64 and 27.19 ± 5.96 nm, respectively. The nanoparticles showed excellent free-radical scavenging activity than the root bark extract Stereospermum suaveolens and the IC50 values obtained were 108.36 ± 1.62, 45.59 ± 0.18, 34.53 ± 0.31 µg/mL, respectively, for the extract, gold and silver nanoparticles. The metal nanoparticles have accomplished good antimicrobial properties towards bacterial and fungal pathogens and were demonstrated herein. The antiproliferative effects of the synthesized silver and gold nanoparticles on human lung adenocarcinoma cells A549 were studied using the MTT assay and the obtained IC50 values 33.81 ± 0.72 and 52.97 ± 0.73 µg/mL lies in the clinical range.
Assuntos
Anti-Infecciosos , Antioxidantes , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus nidulans/crescimento & desenvolvimento , Bactérias/crescimento & desenvolvimento , Bignoniaceae/química , Ouro , Nanopartículas Metálicas/química , Extratos Vegetais/química , Prata , Células A549 , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Anti-Infecciosos/síntese química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Proliferação de Células/efeitos dos fármacos , Ouro/química , Ouro/farmacologia , Humanos , Casca de Planta/química , Raízes de Plantas/química , Prata/química , Prata/farmacologiaRESUMO
Aspergillus nidulans produces sterigmatocystin (ST), a precursor of a carcinogenic secondary metabolite aflatoxin (AF), during its developmental process. ST biosynthesis has been shown to be affected by various regulatory factors. In this study, we investigated the involvement of O-mannosyltransferases (PmtA, PmtB, PmtC), in ST production and morphological development. Deletion of pmtA (ΔpmtA), pmtB (ΔpmtB) or pmtC (ΔpmtC) caused no spore production and a significant decline of vegetative growth. A tremendous decline of ST level was observed in all Δpmt mutants at the third day after inoculation. By extending the growth period, ST production of ΔpmtA and ΔpmtB increased to the wild-type level 7 days after inoculation. On the other hand, ST was not detected from 7- or 14-day cultures in ΔpmtC. Expression levels of aflR gene, an essential regulator of the ST biosynthesis pathway, were also down-regulated in the Δpmt strains. By introducing the aflR overexpression cassette, ST production in the ΔpmtA and ΔpmtB significantly increased to levels comparable to the wild type. However, the presence of the aflR overexpression cassette could not improve ST production in the ΔpmtC mutant. These data suggest that the PMT family is a new endogenous factor that is required for ST biosynthesis in A. nidulans. These findings provide better understanding of the regulatory mechanisms of AF/ST biosynthesis, which can ultimately contribute to our ability to control aflatoxin contamination.
Assuntos
Aspergillus nidulans/metabolismo , Carcinógenos/metabolismo , Isoenzimas/metabolismo , Manosiltransferases/metabolismo , Esterigmatocistina/biossíntese , Aspergillus nidulans/enzimologia , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Técnicas de Silenciamento de Genes , Genes Fúngicos , Teste de Complementação Genética , Isoenzimas/genética , Manosiltransferases/genética , MutaçãoRESUMO
Phosphoribosyl pyrophosphate synthetase, which is encoded by the Prs gene, catalyses the reaction of ribose-5-phosphate and adenine ribonucleotide triphosphate (ATP) and has central importance in cellular metabolism. However, knowledge about how Prs family members function and contribute to total 5-phosphoribosyl-α-1-pyrophosphate (PRPP) synthetase activity is limited. In this study, we identified that the filamentous fungus Aspergillus nidulans genome contains three PRPP synthase-homologous genes (AnprsA, AnprsB and AnprsC), among which AnprsB and AnprsC but not AnprsA are auxotrophic genes. Transcriptional expression profiles revealed that the mRNA levels of AnprsA, AnprsB and AnprsC are dynamic during germination, hyphal growth and sporulation and that they all showed abundant expression during the vigorous hyphal growth time point. Inhibiting the expression of AnprsB or AnprsC in conditional strains produced more effects on the total PRPP synthetase activity than did inhibiting AnprsA, thus indicating that different AnPrs proteins are unequal in their contributions to Prs enzyme activity. In addition, the constitutive overexpression of AnprsA or AnprsC could significantly rescue the defective phenotype of the AnprsB-absent strain, suggesting that the function of AnprsB is not a specific consequence of this auxotrophic gene but instead comes from the contribution of Prs proteins to PRPP synthetase activity.
Assuntos
Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Hifas/crescimento & desenvolvimento , Ribose-Fosfato Pirofosfoquinase/genética , Esporos Fúngicos/crescimento & desenvolvimento , Trifosfato de Adenosina/química , Aspergillus nidulans/crescimento & desenvolvimento , Deleção de Genes , Técnicas de Inativação de Genes , Hifas/genética , Fosforribosil Pirofosfato/biossíntese , RNA Mensageiro/genética , Ribosemonofosfatos/química , Esporos Fúngicos/genéticaRESUMO
Fungal development and secondary metabolite production are coordinated by regulatory complexes as the trimeric velvet complex. Light accelerates asexual but decreases sexual development of the filamentous fungus Aspergillus nidulans. Changes in gene expression and secondary metabolite accumulation in response to environmental stimuli have been the focus of many studies, but a comprehensive comparison during entire development is lacking. We compared snapshots of transcript and metabolite profiles during fungal development in dark or light. Overall 2.014 genes corresponding to 19% of the genome were differentially expressed when submerged vegetative hyphae were compared to surface development. Differentiation was preferentially asexual in light or preferentially sexual connected to delayed asexual development in dark. Light induces significantly gene expression within the first 24-48h after the transfer to surfaces. Many light induced genes are also expressed in dark after a delay of up to two days, which might be required for preparation of enhanced sexual development. Darkness results in a massive transcriptional reprogramming causing a peak of lipid-derived fungal pheromone synthesis (psi factors) during early sexual development and the expression of genes for cell-wall degradation presumably to mobilize the energy for sexual differentiation. Accumulation of secondary metabolites like antitumoral terrequinone A or like emericellamide start under light conditions, whereas the mycotoxin sterigmatocystin or asperthecin and emodin appear under dark conditions during sexual development. Amino acid synthesis and pool rapidly drop after 72-96h in dark. Subsequent initiation of apoptotic cell-death pathways in darkness happens significantly later than in light. This illustrates that fungal adaptation in differentiation and secondary metabolite production to light conditions requires the reprogramming of one fifth of the potential of its genome.
Assuntos
Aspergillus nidulans/metabolismo , Aspergillus nidulans/efeitos da radiação , Perfilação da Expressão Gênica , Luz , Metaboloma , Metabolismo Secundário , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Fatores de TempoRESUMO
Protein ubiquitination is an evolutionarily conserved post-translational modification process in eukaryotes, and it plays an important role in many biological processes. Aspergillus nidulans, a model filamentous fungus, contributes to our understanding of cellular physiology, metabolism and genetics, but its ubiquitination is not completely revealed. In this study, the ubiquitination sites in the proteome of A. nidulans were identified using a highly sensitive mass spectrometry combined with immuno-affinity enrichment of the ubiquitinated peptides. The 4816 ubiquitination sites were identified in 1913 ubiquitinated proteins, accounting for 18.1% of total proteins in A. nidulans. Bioinformatic analysis suggested that the ubiquitinated proteins associated with a number of biological functions and displayed various sub-cellular localisations. Meanwhile, seven motifs were revealed from the ubiquitinated peptides, and significantly over-presented in the different pathways. Comparison of the enriched functional catalogues indicated that the ubiquitination functions divergently during growth of A. nidulans and Saccharomyces cerevisiae. Additionally, the proteins in A. nidulans-specific sub-category (cell growth/morphogenesis) were subjected to the protein interaction analysis which demonstrated that ubiquitination is involved in the comprehensive protein interactions. This study presents a first proteomic view of ubiquitination in the filamentous fungus, and provides an initial framework for exploring the physiological roles of ubiquitination in A. nidulans.
Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Proteínas Fúngicas/metabolismo , Lisina/metabolismo , Proteoma , Proteínas Ubiquitinadas/metabolismo , Motivos de Aminoácidos , Aspergillus nidulans/genética , Análise por Conglomerados , Biologia Computacional/métodos , Proteínas Fúngicas/genética , Perfilação da Expressão Gênica , Anotação de Sequência Molecular , Peptídeos/metabolismo , Matrizes de Pontuação de Posição Específica , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Proteômica/métodos , Proteínas Ubiquitinadas/genética , UbiquitinaçãoRESUMO
The cellular switch from symmetry to polarity in eukaryotes depends on the microtubule (MT) and actin cytoskeletons. In fungi such as Schizosaccharomyces pombe or Aspergillus nidulans, the MT cytoskeleton determines the sites of actin polymerization through cortical cell-end marker proteins. Here we describe A. nidulans MT guidance protein A (MigA) as the first ortholog of the karyogamy protein Kar9 from Saccharomyces cerevisiae in filamentous fungi. A. nidulans MigA interacts with the cortical ApsA protein and is involved in spindle positioning during mitosis. MigA is also associated with septal and nuclear MT organizing centers (MTOCs). Super-resolution photoactivated localization microscopy (PALM) analyses revealed that MigA is recruited to assembling and retracting MT plus ends in an EbA-dependent manner. MigA is required for MT convergence in hyphal tips and plays a role in correct localization of the cell-end markers TeaA and TeaR. In addition, MigA interacts with a class-V myosin, suggesting that an active mechanism exists to capture MTs and to pull the ends along actin filaments. Hence, the organization of MTs and actin depend on each other, and positive feedback loops ensure robust polar growth.
Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Proteínas Fúngicas/metabolismo , Centro Organizador dos Microtúbulos/metabolismo , Aspergillus nidulans/genética , Dineínas/metabolismo , Proteínas Fúngicas/genética , Microtúbulos/metabolismoRESUMO
Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
Assuntos
Antifúngicos/farmacologia , Proteínas Fúngicas/farmacologia , Neosartorya/química , Actinas/metabolismo , Apoptose/efeitos dos fármacos , Aspergillus nidulans/citologia , Aspergillus nidulans/efeitos dos fármacos , Aspergillus nidulans/crescimento & desenvolvimento , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Quitina/metabolismo , Endocitose/efeitos dos fármacos , Proteínas de Ligação ao GTP/metabolismo , Hifas/citologia , Hifas/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
The Spitzenkörper (SPK) is an accumulation of vesicles interleaved with actin microfilaments present at the cytosolic side of the apical plasma membrane (PM) of hyphal tips of many species of filamentous fungi. The physiological role of the SPK has captivated fungal biologists over the years, but only very recently this 'organelle' is starting to be understood in the molecular terminology used for cell biological models. One aspect that has received little attention is the role of cellular membrane asymmetry in the organization of membrane traffic, in particular in the genetic and cell biological model Aspergillus nidulans. The paper by Schultzhaus et al. (2015) in this issue breaks the ice, providing original insight that may foster research in phospholipid composition in the context of intracellular traffic and the organization of the SPK. Notably, it shows that like the stout Neurospora crassaâ SPK, the much slimmer one of A. nidulans, appears to be formed by different strata, altogether suggesting that the SPK might be a mosaic of exocytic carriers with different functional specializations, and a major sorting hub for intracellular membranes.
Assuntos
Adenosina Trifosfatases/metabolismo , Aspergillus nidulans/enzimologia , Aspergillus nidulans/crescimento & desenvolvimento , Endocitose , Proteínas Fúngicas/metabolismo , Hifas/crescimento & desenvolvimentoRESUMO
Endocytosis and exocytosis are strictly segregated at the ends of hyphal cells of filamentous fungi, with a collar of endocytic activity encircling the growing cell tip, which elongates through directed membrane fusion. It has been proposed that this separation supports an endocytic recycling pathway that maintains polar localization of proteins at the growing apex. In a search for proteins in the filamentous fungus Aspergillus nidulans that possess an NPFxD motif, which signals for endocytosis, a Type 4 P-Type ATPase was identified and named DnfA. Interestingly, NPFxD is at a different region of DnfA than the same motif in the Saccharomyces cerevisiae ortholog, although endocytosis is dependent on this motif for both proteins. DnfA is involved in asexual sporulation and polarized growth. Additionally, it is segregated within the Spitzenkörper from another Type 4 P-type ATPase, DnfB. Next, the phosphatidylserine marker GFP::Lact-C2 was expressed in growing hyphae, which revealed that this phospholipid is enriched on the cytosolic face of secretory vesicles. This distribution is affected by deleting either dnfA or dnfB. These findings provide evidence for the spatial and temporal segregation of Type4-ATPases in filamentous fungi, and the asymmetric distribution of phosphatidylserine to the Spitzenkörper in A. nidulans.
Assuntos
Adenosina Trifosfatases/metabolismo , Aspergillus nidulans/enzimologia , Aspergillus nidulans/crescimento & desenvolvimento , Endocitose , Proteínas Fúngicas/metabolismo , Hifas/crescimento & desenvolvimento , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/isolamento & purificação , Aspergillus nidulans/genética , Transporte Biológico , Exocitose , Proteínas Fúngicas/genética , Hifas/enzimologia , Hifas/ultraestrutura , Mutação , Fenótipo , Fosfatidilserinas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/enzimologiaRESUMO
Aspergillus nidulans is an important mold and a model system for the study of fungal cell biology. In addition, invasive A. nidulans pulmonary infections are common in humans with chronic granulomatous disease. The morphological and biochemical transition from dormant conidia into active, growing, filamentous hyphae requires the coordination of numerous biosynthetic, developmental, and metabolic processes. The present study exhibited the diversity of roles performed by seven phosphatases in regulating cell cycle, development, and metabolism in response to glucose and alternative carbon sources. The identified phosphatases highlighted the importance of several signaling pathways regulating filamentous growth, the action of the pyruvate dehydrogenase complex as a metabolic switch controlling carbon usage, and the identification of the key function performed by the α-ketoglutarate dehydrogenase during germination. These novel insights into the fundamental roles of numerous phosphatases in germination and carbon sensing have provided new avenues of research into the identification of inhibitors of fungal germination, with implications for the food, feed, and pharmaceutical industries.
Assuntos
Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Metabolismo Basal , Carbono/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Aspergillus nidulans/crescimento & desenvolvimento , Ciclo Celular/genética , Ciclo do Ácido Cítrico , Análise por Conglomerados , Etanol/metabolismo , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Glicerol/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Redes e Vias Metabólicas , Mutação , Consumo de Oxigênio , Monoéster Fosfórico Hidrolases/genética , Esporos Fúngicos , Trealose/metabolismoRESUMO
P-type Ca(2+)-transporting ATPases are Ca(2+) pumps, extruding cytosolic Ca(2+) to the extracellular environment or the intracellular Ca(2+) store lumens. In budding yeast, Pmr1 (plasma membrane ATPase related), and Pmc1 (plasma membrane calcium-ATPase) cannot be deleted simultaneously for it to survive in standard medium. Here, we deleted two putative Ca(2+) pumps, designated AnPmrA and AnPmcA, from Aspergillus nidulans, and obtained the mutants ΔanpmrA and ΔanpmcA, respectively. Then, using ΔanpmrA as the starting strain, the promoter of its anpmcA was replaced with the alcA promoter to secure the mutant ΔanpmrAalcApmcA or its anpmcA was deleted completely to produce the mutant ΔanpmrAΔpmcA. Different from the case in Saccharomyces cerevisiae, double deletion of anpmrA and anpmcA was not lethal in A. nidulans. In addition, deletion of anpmrA and/or anpmcA had produced growth defects, although overexpression of AnPmc1 in ΔanpmrAalcApmcA could not restore the growth defects that resulted from the loss of AnPmrA. Moreover, we found AnPmrA was indispensable for maintenance of normal morphogenesis, especially in low-Ca(2+)/Mn(2+) environments. Thus, our findings suggest AnPmrA and AnPmcA might play important roles in growth, morphogenesis and cell wall integrity in A. nidulans in a different way from that in yeasts.
Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Parede Celular/enzimologia , Proteínas Fúngicas/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , Aspergillus nidulans/enzimologia , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Cálcio/metabolismo , Parede Celular/genética , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Viabilidade Microbiana , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Deleção de SequênciaRESUMO
Conidial germination is fundamentally important to the growth and dissemination of most fungi. It has been previously shown (K. Hayer, M. Stratford, and D. B. Archer, Appl. Environ. Microbiol. 79:6924-6931, 2013, http://dx.doi.org/10.1128/AEM.02061-13), using sugar analogs, that germination is a 2-stage process involving triggering of germination and then nutrient uptake for hyphal outgrowth. In the present study, we tested this 2-stage germination process using a series of nitrogen-containing compounds for the ability to trigger the breaking of dormancy of Aspergillus niger conidia and then to support the formation of hyphae by acting as nitrogen sources. Triggering and germination were also compared between A. niger and Aspergillus nidulans using 2-deoxy-D-glucose (trigger), D-galactose (nontrigger in A. niger but trigger in A. nidulans), and an N source (required in A. niger but not in A. nidulans). Although most of the nitrogen compounds studied served as nitrogen sources for growth, only some nitrogen compounds could trigger germination of A. niger conidia, and all were related to L-amino acids. Using L-amino acid analogs without either the amine or the carboxylic acid group revealed that both the amine and carboxylic acid groups were essential for an L-amino acid to serve as a trigger molecule. Generally, conidia were able to sense and recognize nitrogen compounds that fitted into a specific size range. There was no evidence of uptake of either triggering or nontriggering compounds over the first 90 min of A. niger conidial germination, suggesting that the germination trigger sensors are not located within the spore.
Assuntos
Aminoácidos/farmacologia , Aspergillus nidulans/efeitos dos fármacos , Aspergillus niger/efeitos dos fármacos , Compostos de Nitrogênio/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus niger/crescimento & desenvolvimento , Radioisótopos de Carbono/análise , Cisteína/farmacologia , Desoxiglucose/farmacologia , Galactose/farmacologia , Hifas , Serina/farmacologia , Esporos Fúngicos/crescimento & desenvolvimento , Valina/farmacologiaRESUMO
Stripe rust is one of the most serious wheat diseases worldwide. The fungus Puccinia striiformis f. sp. tritici (Pst), the causal agent of this disease, is an obligate biotrophic basidiomycete fungus. Numerous studies have shown that dyneins play important roles during fungal growth and propagation. However, knowledge is limited regarding the function of dyneins in Pst. In this study, we cloned the dynein light chain gene PsDLC1 from Pst and characterized its expression. The function of PsDLC1 was determined by heterologous mutant complementation. Expression of PsDLC1 in Aspergillus nidulans partially complemented the defects of the ΔnudG mutant, indicating that PsDLC1 belongs to the dynein light chain LC8 family. In addition, PsDLC1 was identified in Pst using virus-induced gene silencing (VIGS). Knockdown of PsDLC1 produces no significant effect on Pst growth and development, indicating that PsDLC1 is unnecessary for Pst infection of wheat.
Assuntos
Basidiomycota/crescimento & desenvolvimento , Basidiomycota/genética , Dineínas/genética , Dineínas/metabolismo , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Basidiomycota/isolamento & purificação , Clonagem Molecular , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Deleção de Genes , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Teste de Complementação Genética , Doenças das Plantas/microbiologia , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Triticum/microbiologiaRESUMO
Nitric oxide (NO) is a toxic reactive nitrogen species that induces microbial adaption mechanisms. Screening a genomic DNA library identified a new gene, ntpA, that conferred growth tolerance upon Aspergillus nidulans against exogenous NO. The gene encoded a cysteine-rich 23-amino-acid peptide that reacted with NO and S-nitrosoglutathione to generate an S-nitrosated peptide. Disrupting ntpA increased amounts of cellular S-nitrosothiol and NO susceptibility. Thioredoxin and its reductase denitrosated the S-nitrosated peptide, decreased cellular S-nitrosothiol and conferred tolerance against NO, indicating peptide-mediated catalytic NO removal. The peptide binds copper(I) in vitro but is dispensable for metal tolerance in vivo. NO but not metal ions induced production of the peptide and ntpA transcripts. We discovered that the thionein family of peptides has NO-related functions and propose that the new peptide be named NO-inducible nitrosothionein (iNT). The ubiquitous distribution of iNT-like polypeptides constitutes a potent NO-detoxifying mechanism that is conserved among various organisms.
Assuntos
Aspergillus nidulans/metabolismo , Proteínas Fúngicas/metabolismo , Óxido Nítrico/metabolismo , S-Nitrosoglutationa/metabolismo , Tiorredoxinas/metabolismo , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Proteínas Fúngicas/genética , Genes Fúngicos/genética , Óxido Nítrico/antagonistas & inibidores , Espécies Reativas de Nitrogênio/metabolismoRESUMO
Translationally controlled tumor protein (TCTP) is a highly conserved and ubiquitously expressed protein present in all eukaryotes. Cellular functions of TCTP include growth promoting, allergic response and responses to various cellular stresses, but the functions in filamentous fungi have not been reported. In this report, we characterized an Aspergillus nidulans TCTP (TcpA) with high similarity to TCTP. The level of tcpa mRNA was relatively high, both during vegetative growth stage and at early phases of development. TcpA was found predominantly in the nucleus during germination and mycelial growth, and was localized in cytoplasm and nuclei of vesicles on stipes during conidia development. Deletion of tcpA resulted in abnormal hyphal branch formation during vegetative growth. The tcpA deletion inhibited sexual development, but enhanced asexual development via induction of brlA expression. These results imply that TcpA is involved in normal hyphal branch establishment during vegetative growth and also has a role in the balance between asexual and sexual differentiation.
Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Biomarcadores Tumorais/metabolismo , Proteínas Fúngicas/metabolismo , Hifas/crescimento & desenvolvimento , Aspergillus nidulans/citologia , Aspergillus nidulans/genética , Biomarcadores Tumorais/genética , Núcleo Celular/química , Citoplasma/química , Proteínas Fúngicas/genética , Deleção de Genes , Perfilação da Expressão Gênica , Hifas/citologia , Hifas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteína Tumoral 1 Controlada por TraduçãoRESUMO
Deneddylases remove the ubiquitin-like protein Nedd8 from modified proteins. An increased deneddylase activity has been associated with various human cancers. In contrast, we show here that a mutant strain of the model fungus Aspergillus nidulans deficient in two deneddylases is viable but can only grow as a filament and is highly impaired for multicellular development. The DEN1/DenA and the COP9 signalosome (CSN) deneddylases physically interact in A. nidulans as well as in human cells, and CSN targets DEN1/DenA for protein degradation. Fungal development responds to light and requires both deneddylases for an appropriate light reaction. In contrast to CSN, which is necessary for sexual development, DEN1/DenA is required for asexual development. The CSN-DEN1/DenA interaction that affects DEN1/DenA protein levels presumably balances cellular deneddylase activity. A deneddylase disequilibrium impairs multicellular development and suggests that control of deneddylase activity is important for multicellular development.
Assuntos
Aspergillus nidulans , Endopeptidases , Complexos Multiproteicos , Peptídeo Hidrolases , Ubiquitinas , Aspergillus nidulans/genética , Aspergillus nidulans/crescimento & desenvolvimento , Complexo do Signalossomo COP9 , Endopeptidases/genética , Endopeptidases/metabolismo , Regulação Fúngica da Expressão Gênica , Células HeLa , Humanos , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Mutação , Proteína NEDD8 , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Processamento de Proteína Pós-Traducional , Proteólise , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Ubiquitinas/genética , Ubiquitinas/metabolismoRESUMO
The filamentous fungus Aspergillus nidulans carries a single gene for the S-adenosylmethionine (SAM) synthetase SasA, whereas many other organisms possess multiple SAM synthetases. The conserved enzyme catalyzes the reaction of methionine and ATP to the ubiquitous methyl group donor SAM. SAM is the main methyl group donor for methyltransferases to modify DNA, RNA, protein, metabolites, or phospholipid target substrates. We show here that the single A. nidulans SAM synthetase encoding gene sasA is essential. Overexpression of sasA, encoding a predominantly cytoplasmic protein, led to impaired development including only small sterile fruiting bodies which are surrounded by unusually pigmented auxiliary Hülle cells. Hülle cells are the only fungal cell type which does not contain significant amounts of SasA. Sterigmatocystin production is altered when sasA is overexpressed, suggesting defects in coordination of development and secondary metabolism. SasA interacts with various metabolic proteins including methionine or mitochondrial metabolic enzymes as well as proteins involved in fungal morphogenesis. SasA interaction to histone-2B might reflect a putative epigenetic link to gene expression. Our data suggest a distinct role of SasA in coordinating fungal secondary metabolism and development.
Assuntos
Aspergillus nidulans/enzimologia , Aspergillus nidulans/crescimento & desenvolvimento , Proteínas Fúngicas/metabolismo , Metionina Adenosiltransferase/metabolismo , Esterigmatocistina/metabolismo , Sequência de Aminoácidos , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Metionina Adenosiltransferase/química , Metionina Adenosiltransferase/genética , Dados de Sequência Molecular , Filogenia , Alinhamento de SequênciaRESUMO
Cutinases are versatile carboxylic ester hydrolases with great potential in many biocatalytic processes, including biodiesel production. Genome sequence analysis of the model organism Aspergillus nidulans reveals four genes encoding putative cutinases. In this work, we purified and identified for the first time a cutinase (ANCUT2) produced by A. nidulans. ANCUT2 is a 29-kDa protein which consists of 255 amino acid residues. Comparison of the amino acid sequence of ANCUT2 with other microbial cutinase sequences revealed a high degree of homology with other fungal cutinases as well as new features, which include a serine-rich region and conserved cysteines. Cutinase production with different lipidic and carbon sources was also explored. Enzyme activity was induced by olive oil and some triacylglycerides and fatty acids, whereas it was repressed by glucose (1%) and other sugars. In some conditions, a 22-kDa post-translational processing product was also detected. The cutinase nature of the enzyme was confirmed after degradation of apple cutin.