PMID(sorted ascending)
basa regulates cell wall organization and asexual/sexual sporulation ratio in aspergillus nidulans.sphingolipid c4 hydroxylase catalyzes the conversion of dihydrosphingosine to phytosphingosine. in saccharomyces cerevisiae, sur2 is essential for sphingolipid c4 hydroxylation activity but not essential for normal growth. here we demonstrate that the aspergillus nidulans sur2 homolog basa is also required for phytosphingosine biosynthesis but is also essential for viability. we previously reported that a point missense mutation in basa resulted in aberrant cell wall thickening. here our data su ...200717409079
further characterization of the signaling proteolysis step in the aspergillus nidulans ph signal transduction pathway.the aspergillus nidulans ph-responsive transcription factor pacc is modulated by limited, two-step proteolysis. the first, ph-regulated cleavage occurs in the 24-residue highly conserved "signaling protease box" in response to the alkaline ph signal. this is transduced by the pal signaling pathway, containing the predicted calpain-like cysteine protease and likely signaling protease, palb. in this work, we carried out classical mutational analysis of the putative signaling protease palb, and we ...200717416893
the sska and srra response regulators are implicated in oxidative stress responses of hyphae and asexual spores in the phosphorelay signaling network of aspergillus nidulans.histidine-to-aspartate (his-asp) phosphorelay (or two-component) systems are common signal transduction mechanisms implicated in a wide variety of cellular responses to environmental stimuli in both prokaryotes and eukaryotes. for a model filamentous fungi, aspergillus nidulans, in this study we first compiled a complete list of his-asp phosphorelay components, including 15 genes for his-kinase (hk), four genes for response regulator (rr), and only one for histidine-containing phosphotransfer in ...200717420584
developmental regulation of the glyoxylate cycle in the human pathogen penicillium marneffei.penicillium marneffei is a thermally dimorphic opportunistic human pathogen with a saprophytic filamentous hyphal form at 25 degrees c and a pathogenic unicellular yeast form at 37 degrees c. during infection. p. marneffei yeast cells exist intracellularly in macrophages. to cope with nutrient deprivation during the infection process, a number of pathogens employ the glyoxylate cycle to utilize fatty acids as carbon sources. the genes which constitute this pathway have been implicated in pathoge ...200617427290
purification and characterization of the feii- and alpha-ketoglutarate-dependent xanthine hydroxylase from aspergillus nidulans.his6-tagged xanthine/alpha-ketoglutarate (alphakg) dioxygenase (xana) of aspergillus nidulans was purified from both the fungal mycelium and recombinant escherichia coli cells, and the properties of the two forms of the protein were compared. evidence was obtained for both n- and o-linked glycosylation on the fungus-derived xana, which aggregates into an apparent dodecamer, while bacterium-derived xana is free of glycosylation and behaves as a monomer. immunological methods identify phosphothreo ...200717429948
target-based approach to inhibitors of histone arginine methyltransferases.lysine and arginine methyltransferases participate in the post-translational modification of histones and regulate key cellular functions. so far only one arginine methyltransferase inhibitor discovered by random screening was available. we present the first target-based approach to protein arginine methyltransferase (prmt) inhibitors. homology models of human and aspergillus nidulans prmt1 were generated from available x-ray structures of rat prmts. the nci diversity set was filtered by a targe ...200717432842
genetic manipulation of aspergillus nidulans: meiotic progeny for genetic analysis and strain construction.the multicellular microbial eukaryote aspergillus nidulans is an excellent model for the study of a wide array of biological processes. studies in this system contribute significantly to understanding fundamental biological principles and are relevant for biotechnology and industrial applications, as well as human, animal and plant fungal pathogenesis. a. nidulans is easily manipulated using classical and molecular genetics. here, we describe the storage and handling of a. nidulans and procedure ...200717446881
genetic manipulation of aspergillus nidulans: heterokaryons and diploids for dominance, complementation and haploidization analyses.the haploid microbial eukaryote aspergillus nidulans is a powerful genetic system, which allows analysis of a broad range of biological phenomena. in addition to conventional analysis of meiotic progeny in a single generation, parasexual analysis affords a rapid and convenient method for genetic analysis. we describe the construction of a. nidulans heterokaryons and diploids for use in genetic analysis to determine dominance and conduct complementation tests. we also describe the rapid mapping o ...200717446882
comparative studies of differential expression of chitinolytic enzymes encoded by chia, chib, chic and naga genes in aspergillus nidulans.n-acetyl-d-glucosamine, chito-oligomers and carbon starvation regulated chia, chib, and naga gene expressions in aspergillus nidulans cultures. the gene expression patterns of the main extracellular endochitinase chib and the n-acetyl-beta-d-glucosaminidase naga were similar, and the chib-naga enzyme system may play a morphological and/or nutritional role during autolysis. alterations in the levels of reactive oxygen species or in the glutathione-glutathione disulfide redox balance, characterist ...200617455791
targeting polyamines of aspergillus nidulans by sirna specific to fungal ornithine decarboxylase gene.aspergillus nidulans is a filamentous, ubiquitous and opportunistic pathogenic fungus, which causes fatal invasive aspergillosis among immunocompromised patients. as a prelude to the investigations on the possible control of human fungal diseases by selective targeting of fungal polyamines that are essential for fungal growth and development by rnai strategy, we have examined the effect of sirna specific to a key polyamine biosynthesis gene ornithine decarboxylase (odc) on the in vitro germinati ...200717464842
mitotic recombination accelerates adaptation in the fungus aspergillus nidulans.understanding the prevalence of sexual reproduction in eukaryotes is a hard problem. at least two aspects still defy a fully satisfactory explanation, the functional significance of genetic recombination and the great variation among taxa in the relative lengths of the haploid and diploid phases in the sexual cycle. we have performed an experimental study to explore the specific advantages of haploidy or diploidy in the fungus aspergillus nidulans. comparing the rate of adaptation to a novel env ...200717465683
coupling the gal4 uas system with alcr for versatile cell type-specific chemically inducible gene expression in arabidopsis.the aspergillus alc regulon encodes a transcription factor, alcr, which regulates transcription from cognate promoters such as alca(p). in the presence of suitable chemical inducers, alcr activates gene expression from alca(p). the alc regulon can be transferred to other species and can be used to control the expression of reporter, metabolic and developmental genes in response to low-level ethanol exposure. in this paper, we describe a versatile system for targeting the alc regulon to specific ...200717470056
an eight-subunit cop9 signalosome with an intact jamm motif is required for fungal fruit body formation.fruit body formation in filamentous fungi is a complex and yet hardly understood process. we show here that protein turnover control is crucial for aspergillus nidulans development. deletion of genes encoding cop9 signalosome (csn) subunits 1, 2, 4, or 5 resulted in identical blocks in fruit body formation. the csn multiprotein complex controls ubiquitin-dependent protein degradation in eukaryotes. six csn subunits interacted in a yeast two-hybrid analysis, and the complete eight-subunit csn was ...200717470786
multiple fungal enzymes possess cysteine synthase activity in vitro.we present evidence that there are at least three aspergillus nidulans enzymes which catalyze in vitro the reaction of o-acetylserine (oas) with sulfide forming cysteine. this activity is shared by cysteine synthase (cs) encoded by the cysb gene, homocysteine synthase encoded by cysd and by at least one more enzyme. moreover, arginine, histidine or proline starvation leads to derepression of cs activity even in the cysb,cysd double mutant strains, while neither cysb nor cysd gene transcription i ...200717482430
role of respiration in the germination process of the pathogenic mold aspergillus fumigatus.inhalation of resting conidia is usually the first step of a systemic infection caused by the opportunistic fungal pathogen aspergillus fumigatus. in the lung, the inhaled spores encounter an environment that permits germination. however, the relative importance of certain environmental conditions for conidial activation and subsequent hyphae formation has so far not been analyzed in detail. in this study, we studied the role of oxygen during germination. we found that inhibitors of the respirat ...200717486408
eurotiomycetes: eurotiomycetidae and chaetothyriomycetidae.the class eurotiomycetes (ascomycota, pezizomycotina) is a monophyletic group comprising two major clades of very different ascomycetous fungi: (i) the subclass eurotiomycetidae, a clade that contains most of the fungi previously recognized as plectomycetes because of their mostly enclosed ascomata and prototunicate asci; and (ii) the subclass chaetothyriomycetidae, a group of fungi that produce ascomata with an opening reminiscent of those produced by dothideomycetes or sordariomycetes. in this ...200617486980
the mitochondrial genome from the thermal dimorphic fungus paracoccidioides brasiliensis.we present here the sequence of the mitochondrial dna of the pathogenic thermodimorphic fungus paracoccidioides brasiliensis, agent of an endemic disease in most south american countries. the sequenced genome has 71 334 bp and is organized as a circular molecule with two gaps of unknown size flanking the middle exon of the nad5 gene. we located genes coding for the three subunits of the atp synthase (atp6, atp8 and atp9), the apocytochrome b (cob), three subunits of the cytochrome c oxidase enzy ...200717492801
the aspergillus nidulans putative kinase, kfsa (kinase for septation), plays a role in septation and is required for efficient asexual spore aspergillus nidulans nuclear division and cytokinesis are coupled processes during asexual sporulation. metulae, phialides and conidia contain a single nucleus. here we describe the role of a putative saccharomyces cerevisiae kin4-related kinase, kfsa (kinase for septation) in the control of septum formation in a. nidulans. the kfsa deletion caused an increase in the number of conidiophores with septa in their stalks from 20% in wild type to 60% in the mutant strain. interestingly, 7% of metu ...200717500016
human nima-related kinase 6 is one of the fe65 ww domain binding proteins.the aspergillus nidulans protein nima (never in mitosis, gene a) is a protein kinase required for initiation of mitosis, whereas its inactivation is necessary for mitotic exit. here, we present evidence that human nek6 is associated with fe65. based on the presence of fe65 ww domain binding motifs ((267)pplp(270)) in the nek6 catalytic domain, we observed that nek6 interacts physically with fe65 both in vivo and in vitro, using a pull-down approach. additionally, we detected co-localization of n ...200717512906
regulation of expression and kinetic modeling of substrate interactions of a uracil transporter in aspergillus nidulans.early genetic evidence suggested that a. nidulans possesses at least one uracil transporter. a gene, named furd, was recently identified by reverse genetics and in silico approaches and we confirm here that it encodes a high-affinity, high-capacity, uracil transporter. in this work, we study the regulation of expression of furd and develop a kinetic model describing transporter-substrate interactions. the furd gene is not expressed in resting conidiospores, is transcriptionally activated and rea ...200717520477
synthetic ecosystems based on airborne inter- and intrakingdom communication.intercellular communication within an organism, between populations, or across species and kingdoms forms the basis of many ecosystems in which organisms coexist through symbiotic, parasitic, or predator-prey relationships. using multistep airborne communication and signal transduction, we present synthetic ecosystems within a mammalian cell population, in mice, or across species and kingdoms. inter- and intrakingdom communication was enabled by using sender cells that produce volatile aldehydes ...200717551014
molecular cloning, characterization, and expression of a chitinase from the entomopathogenic fungus paecilomyces javanicus.paecilomyces javanicus is an entomopathogenic fungus of coleopteran and lepidopteran insects. here we report on cloning, characterization, and expression patterns of a chitinase from p. javanicus. a strong chitinase activity was detected in p. javanicus cultures added to chitin. the full-length cdna, designated pjchi-1, was cloned from mycelia by using both degenerate primer/reverse transcription polymerase chain reaction (rt-pcr) amplification and 5'-/3'-race extension. the 1.18-kb cdna gene co ...200717551789
steric analysis of 8-hydroxy- and 10-hydroxyoctadecadienoic acids and dihydroxyoctadecadienoic acids formed from 8r-hydroperoxyoctadecadienoic acid by hydroperoxide isomerases.8-hydroxyoctadeca-9z,12z-dienoic acid (8-hode) and 10-hydroxyoctadeca-8e,12z-octadecadienoic acid (10-hode) are produced by fungi, e.g., 8r-hode by gaeumannomyces graminis (take-all of wheat) and aspergillus nidulans, 10s-hode by lentinula edodes, and 10r-hode by epichloe typhina. racemic [8-(2)h]8-hode and [10-(2)h]10-hode were prepared by oxidation of 8- and 10-hode to keto fatty acids by dess-martin periodinane followed by reduction to hydroxy fatty acids with nab(2)h(4). the hydroxy fatty ac ...200717553451
interaction of hapx with the ccaat-binding complex--a novel mechanism of gene regulation by iron.iron homeostasis requires subtle control systems, as iron is both essential and toxic. in aspergillus nidulans, iron represses iron acquisition via the gata factor srea, and induces iron-dependent pathways at the transcriptional level, by a so far unknown mechanism. here, we demonstrate that iron-dependent pathways (e.g., heme biosynthesis) are repressed during iron-depleted conditions by physical interaction of hapx with the ccaat-binding core complex (cbc). proteome analysis identified putativ ...200717568774
characterization of afpa, an alkaline foam protein from cultures of fusarium culmorum and its identification in infected malt.the objective of this study was to evaluate the capability of fusarium culmorum to produce non-hydrophobin surface-active proteins in vitro, to isolate and characterize such proteins from liquid cultures, to analyse their effect on overfoaming (gushing) of beer and to elucidate their prevalence in pure cultures and infected malt.200717584451
a one-pot chemoenzymatic synthesis for the universal precursor of antidiabetes and antiviral bis-indolylquinones.bis-indolylquinones represent a class of fungal natural products that display antiretroviral, antidiabetes, or cytotoxic bioactivities. recent advances in aspergillus genomic mining efforts have led to the discovery of the tdia-e-gene cluster, which is the first genetic locus dedicated to bis-indolylquinone biosynthesis. we have now genetically and biochemically characterized the enzymes tdia (bis-indolylquinone synthetase) and tdid (l-tryptophan:phenylpyruvate aminotransferase), which, together ...200717584611
nek7 is a centrosomal kinase critical for microtubule nucleation.nima in aspergillus nidulans is a mitotic kinase for chromosome condensation and segregation. we characterized nek7, a human homologue of aspergillus nima. nek7 was located at the centrosome throughout the cell cycle. temporal localization of nek7 at midbody of the cytokinetic cell was also observed. nek7 knockdown by rnai caused a prometaphase arrest of the cell cycle with monopolar or disorganized spindle. we propose that such defects in spindle assembly are resulted from reduction in microtub ...200717586473
analysis of septins across kingdoms reveals orthology and new motifs.septins are cytoskeletal gtpase proteins first discovered in the fungus saccharomyces cerevisiae where they organize the septum and link nuclear division with cell division. more recently septins have been found in animals where they are important in processes ranging from actin and microtubule organization to embryonic patterning and where defects in septins have been implicated in human disease. previous studies suggested that many animal septins fell into independent evolutionary groups, conf ...200717601340
a clc chloride channel plays an essential role in copper homeostasis in aspergillus nidulans at increased extracellular copper concentrations.a putative clc voltage-gated anion channel gene from aspergillus nidulans (anclca) is characterised. the expression of the anclca cdna restored the iron-limited growth of the saccharomyces cerevisiae clc null mutant strain (gef1) suggesting that anclca functions as a chloride channel. an anclca conditional mutant was created and exhibited a strong and specific growth inhibition in the presence of extracellular copper concentrations >18 microm. this sensitivity was shown to be the result of a hyp ...200717601488
mpka-dependent and -independent cell wall integrity signaling in aspergillus nidulans.cell wall integrity signaling (cwis) maintains cell wall biogenesis in fungi, but only a few transcription factors (tfs) and target genes downstream of the cwis cascade in filamentous fungi are known. because a mitogen-activated protein kinase (mpka) is a key cwis enzyme, the transcriptional regulation of mpka and of cell wall-related genes (cwgs) is important in cell wall biogenesis. we cloned aspergillus nidulans mpka; rlma, a tf gene orthologous to saccharomyces cerevisiae rlm1 that encodes r ...200717601879
transformation of taxol-producing endophytic fungi by restriction enzyme-mediated integration (remi).the remi method was used to introduce the plasmid pv2 harboring the hygromycin b phosphotransferase (hph) gene controlled by the aspergillus nidulans trpc promoter and the trpc terminator into a taxol-producing endophytic fungus bt2. remi transformation yielded stable transformants capable of continuing to grow on pda medium containing 125 mug ml(-1) hygromycin b. the transformation efficiency was about 5-6 transformants mug(-1) plasmid dna. the presence of hph gene in transformants was confirme ...200717608701
fungal photoreceptors: sensory molecules for fungal development and behaviour.light regulates fungal development and behaviour and activates metabolic pathways. in addition, light is one of the many signals that fungi use to perceive and interact with the environment. in the ascomycete neurospora crassa blue light is perceived by the white collar (wc) complex, a protein complex formed by wc-1 and wc-2. wc-1 is a protein with a flavin-binding domain and a zinc-finger domain, and interacts with wc-2, another zinc-finger domain protein. the wc complex operates as a photorece ...200717609765
histone deacetylase activity regulates chemical diversity in aspergillus.bioactive small molecules are critical in aspergillus species during their development and interaction with other organisms. genes dedicated to their production are encoded in clusters that can be located throughout the genome. we show that deletion of hdaa, encoding an aspergillus nidulans histone deacetylase (hdac), causes transcriptional activation of two telomere-proximal gene clusters--and subsequent increased levels of the corresponding molecules (toxin and antibiotic)--but not of a telome ...200717616629
characterization of the bzip-type transcription factor napa with reference to oxidative stress response in aspergillus nidulans.microorganisms growing in natural habitats are constantly confronted with a wide variety of external stresses. here we provide several lines of experimental evidence for the thesis that the filamentous fungus aspergillus nidulans has a homolog of the ap-1-like bzip transcription factor, which is known to play general roles in oxidative responses in many types of yeast.200717617701
novel reporter gene expression systems for monitoring activation of the aspergillus nidulans hog pathway.the aspergillus nidulans high-osmolarity glycerol response (anhog) pathway is involved in osmoadaptation. we found that fludioxonil, a fungicide, causes improper activation of hoga mitogen-activated protein kinase (mapk) in a. nidulans. here we present novel reporter systems for monitoring activation of the anhog pathway. the promoter region of gfdb (glycerol-3-phosphate dehydrogenase), whose expression depends on the presence of hoga, was fused to a beta-glucuronidase uida gene (gus) to constru ...200717617716
gene duplication, modularity and adaptation in the evolution of the aflatoxin gene cluster.the biosynthesis of aflatoxin (af) involves over 20 enzymatic reactions in a complex polyketide pathway that converts acetate and malonate to the intermediates sterigmatocystin (st) and o-methylsterigmatocystin (omst), the respective penultimate and ultimate precursors of af. although these precursors are chemically and structurally very similar, their accumulation differs at the species level for aspergilli. notable examples are a. nidulans that synthesizes only st, a. flavus that makes predomi ...200717620135
neuronal migration: unraveling the molecular pathway with humans, mice, and a fungus.this review highlights the utility of comparative genetics in understanding the molecular mechanisms that underlie neuronal migration. it is apparent from studies in humans, mice, and a fungus that nuclear migration is a key component of neuronal migration and that both are dependent on a dynamic microtubule network. in vertebrates regulation of this network involves a complex pathway that is dependent on extracellular guidance cues, membrane-bound receptors, intracellular signaling molecules, p ...200717629745
aspergillus nidulans conidiation genes dewa, flug, and stua are differentially regulated in early vegetative growth.microarray analysis was used to identify transcriptional changes in early vegetative growth of the filamentous fungus aspergillus nidulans. the results suggest that the previously identified conidiation genes dewa, flug, and stua may function in isotropic expansion during early vegetative growth and asexual reproduction.200717630328
response regulators srra and sska are central components of a phosphorelay system involved in stress signal transduction and asexual sporulation in aspergillus nidulans.among eukaryotes, only slime molds, fungi, and plants contain signal transduction phosphorelay systems. in filamentous fungi, multiple sensor kinases appear to use a single histidine-containing phosphotransfer (hpt) protein to relay signals to two response regulators (rr). in aspergillus nidulans, the rr sska mediates activation of the mitogen-activated protein kinase saka in response to osmotic and oxidative stress, whereas the functions of the rr srra were unknown. we used a genetic approach t ...200717630329
neurospora crassa ve-1 affects asexual conidiation.the velvet factor of the homothallic fungus aspergillus nidulans promotes sexual fruiting body formation. the encoding vea gene is conserved among fungi, including the ascomycete neurospora crassa. there, the orthologous ve-1 gene encodes a deduced protein with high similarity to a. nidulans vea. cross-complementation experiments suggest that both the promoter and the coding sequence of n. crassa ve-1 are functional to complement the phenotype of an a. nidulans deletion mutant. moreover, ve-1 ex ...200817631397
the thioredoxin system of the filamentous fungus aspergillus nidulans: impact on development and oxidative stress response.redox regulation has been shown to be of increasing importance for many cellular processes. here, redox homeostasis was addressed in aspergillus nidulans, an important model organism for fundamental biological questions such as development, gene regulation or the regulation of the production of secondary metabolites. we describe the characterization of a thioredoxin system from the filamentous fungus a. nidulans. the a. nidulans thioredoxin a (antrxa) is an 11.6-kda protein with a characteristic ...200717631497
a small membrane-peripheral region close to the active center determines regioselectivity of membrane-bound fatty acid desaturases from aspergillus nidulans.fatty acid desaturases catalyze the introduction of double bonds at specific positions of an acyl chain and are categorized according to their substrate specificity and regioselectivity. the current understanding of membrane-bound desaturases is based on mutant studies, biochemical topology analysis, and the comparison of related enzymes with divergent functionality. because structural information is lacking, the principles of membrane-bound desaturase specificity are still not understood despit ...200717636265
protein environment facilitates o2 binding in non-heme iron enzyme. an insight from oniom calculations on isopenicillin n synthase (ipns).binding of dioxygen to a non-heme enzyme has been modeled using the oniom combined quantum mechanical/molecular mechanical (qm/mm) method. for the present system, isopenicillin n synthase (ipns), binding of dioxygen is stabilized by 8-10 kcal/mol for a qm:mm (b3lyp:amber) protein model compared to a quantum mechanical model of the active site only. in the protein system, the free energy change of o2 binding is close to zero. two major factors consistently stabilize o2 binding. the first effect, ...200717637052
a single acyl-coa dehydrogenase is required for catabolism of isoleucine, valine and short-chain fatty acids in aspergillus acyl-coa dehydrogenase has been identified as part of the mitochondrial beta-oxidation pathway in the ascomycete fungus aspergillus nidulans. disruption of the scda gene prevented use of butyric acid (c(4)) and hexanoic acid (c(6)) as carbon sources and reduced cellular butyryl-coa dehydrogenase activity by 7.5-fold. while the mutant strain exhibited wild-type levels of growth on erucic acid (c(22:1)) and oleic acid (c(18:1)), some reduction in growth was observed with myristic acid (c(14)). ...200817656140
asexual recombination in a uvsh mutant of aspergillus nidulans.mutations in the gene uvsh of aspergillus nidulans result in increased spontaneous chromosome instability and increased intragenic and intergenic mitotic recombination in homozygous diploids. the aim of the present work was to obtain a uvs mutant of a. nidulans and to use it for the isolation of asexual recombinants (parameiotic segregants). the mutant uvsh, named b511, showed normal frequency of meiotic recombination in sexual crosses and high frequency of parameiotic segregants in the parasexu ...200717657356
dioctatin a is a strong inhibitor of aflatoxin production by aspergillus parasiticus.dioctatin a (dota), a metabolite of streptomyces, is known to be an inhibitor of human dipeptidyl aminopeptidase ii. here, it was found that dota strongly inhibited aflatoxin production by aspergillus parasiticus, with an ic50 value of 4.0 microm. the mycelial growth of the fungus was not affected by the addition of dota at a concentration of 50 microm, but inhibition of conidiation was observed at the same concentration. dota inhibited production of norsolorinic acid, an early biosynthetic inte ...200717660441
mating type and the genetic basis of self-fertility in the model fungus aspergillus nidulans.sexual reproduction occurs in two fundamentally different ways: by outcrossing, in which two distinct partners contribute nuclei, or by self-fertilization (selfing), in which both nuclei are derived from the same individual. selfing is common in flowering plants, fungi, and some animal taxa. we investigated the genetic basis of selfing in the homothallic fungus aspergillus nidulans. we demonstrate that alpha and high-mobility group domain mating-type (mat) genes, found in outcrossing species, ar ...200717669651
rapid isolation of fungal genomic dna suitable for long distance pcr.a quick and reliable method for screening fungal transformants for specific genetic modifications is essential for many molecular applications. we have compared the applicability of a few rapid dna extraction methods for myrothecium and aspergillus and tested the resulting dna as to its suitability for pcr. for myrothecium gramineum, the highest dna concentration was obtained with the procedure described by n. vanittanakom et al. (j clin microbiol 2002, 40: 1739-1742). for a. nidulans, concentra ...200717680211
secondary chemicals protect mould from fungivory.the vast repertoire of toxic fungal secondary metabolites has long been assumed to have an evolved protective role against fungivory. it still remains elusive, however, whether fungi contain these compounds as an anti-predator adaptation. we demonstrate that loss of secondary metabolites in the soil mould aspergillus nidulans causes, under the attack of the fungivorous springtail folsomia candida, a disadvantage to the fungus. springtails exhibited a distinct preference for feeding on a mutant d ...200717686752
evidence for post-translational regulation of nrta, the aspergillus nidulans high-affinity nitrate, influx and efflux of (13)no(3)(-), and net fluxes of (14)no(3)(-) and (14)no(2)(-), were measured in aspergillus nidulans mutants niad171 and niia5, devoid of nitrate reductase (nr) and nitrite reductase (nir) activities, respectively. transcript and protein abundances of nrta, the a. nidulans principal high-affinity no(3)(-) transporter, were determined using semiquantitative reverse transcription-polymerase chain reaction and western blots, respectively. (13)no(3)(-) influx in niad171 wa ...200717688585
conrad: gene prediction using conditional random fields.we present conrad, the first comparative gene predictor based on semi-markov conditional random fields (smcrfs). unlike the best standalone gene predictors, which are based on generalized hidden markov models (ghmms) and trained by maximum likelihood, conrad is discriminatively trained to maximize annotation accuracy. in addition, unlike the best annotation pipelines, which rely on heuristic and ad hoc decision rules to combine standalone gene predictors with additional information such as ests ...200717690204
light represses conidiation in koji mold aspergillus the filamentous fungus aspergillus oryzae, there has been no report on photoreaction. here we investigated the effect of light in a. oryzae and found that conidiation was repressed by white light. this reaction is contrary to that of other aspergilli, which show abundant conidiation under light. moreover, red light also caused reduced conidiation. genome sequencing of a. oryzae indicated the existence of homologs of some light-related genes in other filamentous fungi. to approach the molecula ...200717690479
pina from aspergillus nidulans binds to ps/pt-p motifs using the same loop i and xp groove as mammalian pin1.binding of the cdc25c-t48 ligand to pina from aspergillus nidulans has been characterised by the identification of 15n and 1h resonances from 1h-15n hsqc nmr titration experiments using previous backbone assignments. it is shown that the binding site for the cdc25c-t48 ligand with pina is the same as in the mammalian protein pin1, although with a reduced binding affinity. it had previously been proposed that the arginine residue (r17) in the loop i region of the pin1 ww domain is essential for b ...200717693144
palc, one of two bro1 domain proteins in the fungal ph signalling pathway, localizes to cortical structures and binds vps32.palc, distantly related to saccharomyces cerevisiae peripheral endosomal sorting complexes required for transport iii (escrt-iii) component bro1p and one of six aspergillus nidulans ph signalling proteins, contains a bro1 domain. green fluorescent protein (gfp)-tagged palc is recruited to plasma membrane-associated punctate structures upon alkalinization, when ph signalling is active. palc recruitment to these structures is dependent on the seven transmembrane domain (7-tmd) receptor and likely ...200717696968
femtochemistry in enzyme catalysis: dna photolyase.photolyase uses light energy to split uv-induced cyclobutane pyrimidine dimers in damaged dna. this photoenzyme encompasses a series of elementary dynamical processes during repair function from early photoinitiation by a photoantenna molecule to enhance repair efficiency, to in vitro photoreduction through aromatic residues to reconvert the cofactor to the active form, and to final photorepair to fix damaged dna. the corresponding series of dynamics include resonance energy transfer, intraprote ...200717703066
the aspergillus nidulans ceta and cala genes are involved in conidial germination and cell wall morphogenesis.the aspergillus nidulans genes ceta (an3079.2) and cala (an7619.2) encode a novel class of fungal thaumatin-like proteins of unknown function. deletion of ceta does not result in an observable phenotype [greenstein, s., shadkchan, y., jadoun, j., sharon, c., markovich, s., osherov, n., 2006. analysis of the aspergillus nidulans thaumatin-like ceta gene and evidence for transcriptional repression of pyr4 expression in the ceta-disrupted strain. fungal genet. biol. 43, 42-53]. we prepared knockout ...200817703972
transient disruption of non-homologous end-joining facilitates targeted genome manipulations in the filamentous fungus aspergillus nidulans.we have developed a transiently disrupted nkua system in aspergillus nidulans for efficient gene targeting. the nkua disruption was made by inserting a counter-selectable marker flanked by a direct repeat (dr) composed of nkua sequences. in the disrupted state, the non-homologous end-joining (nhej) activity is abolished and gene targeting can be performed with success rates identical to those obtained with permanent nkua knock-out strains. when gene targeting is complete, the functional nkua all ...200817703973
terrequinone a biosynthesis through l-tryptophan oxidation, dimerization and bisprenylation.the antitumor fungal metabolite terrequinone a, identified in extracts of aspergillus sp., is biosynthesized by the five-gene cluster tdia-tdie. in this work, we have overproduced all five proteins (tdia-tdie) in the bacterial host escherichia coli, fully reconstituting the biosynthesis of terrequinone a. this pathway involves aminotransferase activity, head-to-tail dimerization and bisprenylation of the scaffold to yield the benzoquinone natural product. we have established that tdid is a pyrid ...200717704773
arginine catabolism in aspergillus nidulans is regulated by the rrma gene coding for the rna-binding protein.expression of aspergillus nidulans arginine catabolism genes, agaa and otaa, is regulated at the level of transcription by a specific induction and two global carbon and nitrogen repression systems. post-transcriptional and/or post-translational mechanisms have also been proposed to operate additionally. gene tagging with transposon impala allowed us to select the rrma gene. rrma protein contains three conserved rrm domains, typical for rna-binding proteins. the gene has a complex structure with ...200717719249
role of the transcriptional activator xlnr of fusarium oxysporum in regulation of xylanase genes and virulence.fungal infection of plants involves degradation of the host cell wall through the action of lytic enzymes secreted by the pathogen. the role of these enzymes in virulence is difficult to determine due to their functional redundancy and, therefore, remains controversial. here, we have studied xlnr, a zinc-finger transcription factor from the vascular wilt pathogen fusarium oxysporum that is orthologous to the major transcriptional activator of xylanase genes in aspergillus spp. transcription of t ...200717722701
mitotic regulation by nima-related kinases.abstract: the nima-related kinases represent a family of serine/threonine kinases implicated in cell cycle control. the founding member of this family, the nima kinase of aspergillus nidulans, as well as the fission yeast homologue fin1, contribute to multiple aspects of mitotic progression including the timing of mitotic entry, chromatin condensation, spindle organization and cytokinesis. mammals contain a large family of eleven nima-related kinases, named nek1 to nek11. of these, there is now ...200717727698
the pan-ac assay: a single-reaction real-time pcr test for quantitative detection of a broad range of aspergillus and candida view of the growing incidence and the high mortality of invasive aspergillosis and candidiasis, adequate diagnostic techniques permitting timely onset of treatment are of paramount importance. more than 90 % of all invasive fungal infections in immunocompromised individuals can be attributed to candida and aspergillus species. to date, standardized techniques permitting rapid, sensitive and, no less importantly, economic screening for the clinically most relevant fungi are lacking. in the pre ...200717761478
fungal nucleobase transporters.early genetic and physiological work in bacteria and fungi has suggested the presence of highly specific nucleobase transport systems. similar transport systems are now known to exist in algae, plants, protozoa and metazoa. within the last 15 years, a small number of microbial genes encoding nucleobase transporters have been cloned and studied in great detail. the sequences of several other putative proteins submitted to databases are homologous to the microbial nucleobase transporters but their ...200717784857
effect of caspofungin on metabolite profiles of aspergillus species determined by nuclear magnetic resonance spectroscopy.invasive aspergillosis remains a potentially life-threatening infection, the incidence of which is increasing. current methods used to determine the susceptibilities of aspergillus strains to antifungal drugs are often unreliable. nuclear magnetic resonance (nmr) spectroscopy can identify the metabolic complement of microorganisms while monitoring nutrient utilization from the incubation medium. we used 600-mhz (1)h nmr spectroscopy to monitor the metabolic responses of five aspergillus species ...200717785514
one enzyme makes a fungal pathogen, but not a saprophyte, virulent on a new host plant.certain genes of nectria haematococca, a fingal pathogen of pea (pisum sativum), encode pisatin demethylase (pda), a cytochrome p-450 monoxygenase that detoxifies the phytoalexin pisatin. because pda is required by n.haematococca for pathogenicity on pea, pisatin helps defend pea against n. haematococca. the possibility that pisatin is a general defense factormicrothat is, that pda can confer pathogenicity to fungi not normally pathogenic on peamicrowas investigated. genes encoding pda were tran ...198917839018
lissencephaly and lis1: insights into the molecular mechanisms of neuronal migration and development.lissencephaly is a severe human neuronal migration defect characterized by a smooth cerebral surface, mental retardation and seizures. lis1 was first gene cloned in an organism important for neuronal migration, as it was deleted or mutated in patients with lissencephaly in a heterozygous fashion. studies in model organisms, particularly aspergillus nidulans, as well as those in the mouse, have uncovered an evolutionarily conserved pathway that involves lis1 and cytoplasmic dynein. this pathway c ...200717850624
transcriptional control of nmra by the bzip transcription factor meab reveals a new level of nitrogen regulation in aspergillus nidulans.fungi can use a diverse range of nitrogen sources. some nitrogen sources sustain a rapid growth rate and are used in preference to less readily metabolized nitrogen sources. the mechanisms involved in this control of nitrogen utilization have been studied in the model filamentous ascomycete, aspergillus nidulans. the gata transcription factor area is necessary for the expression of nitrogen-catabolic permeases and enzymes. area activity is controlled by multiple mechanisms including regulated ar ...200717854403
effect of selected natural dyes in reduction on colour changes of egyptian linen textiles by fungi.linen is the most historical egyptian textile fibre liable to fungal deterioration. fungal deterioration of dyed linen textiles may appear as undesirable different stains. in order to success in removing of fungal stains from biodeteriorated historical egyptian dyed linen textiles, it is necessary to understand the nature and causes of these stains, hence their subsequent removal. so this paper aims to investigate the effect of fungi on dyed linen textiles. in this study linen textile samples we ...200717867537
evaluation of thermophilic fungal consortium for paddy straw composting.out of 10 thermophilic fungi isolated from wheat straw, farm yard manure, and soil, only three showed highest cellobiase, carboxymethyl cellulase, xylanase, and fpase activities. they were identified as aspergillus nidulans (th(4)), scytalidium thermophilum (th(5)), and humicola sp. (th(10)). a fungal consortium of these three fungi was used to compost a mixture (1:1) of silica rich paddy straw and lignin rich soybean trash. the composting of paddy straw for 3 months, during summer period in nor ...200817874191
transcriptome analysis of the aspergillus nidulans atma (atm, ataxia-telangiectasia mutated) null mutant.atm is a phosphatidyl-3-kinase-related protein kinase that functions as a central regulator of dna damage response in eukaryotes. in humans, mutations in atm cause the devastating neurodegenerative disease ataxia-telangiectasia. previously, we characterized the homologue of atm (atma) in the filamentous fungus aspergillus nidulans. in addition to its expected role in the dna damage response, we found that atma is also required for polarized hyphal growth. our results suggested that atma probably ...200717880424
characterization and kinetics of the major purine transporters in aspergillus fumigatus.three genes encoding putative purine transporters have been identified in silico in the genome of aspergillus fumigatus by their very close similarity of their translation products to well-studied homologues in a. nidulans. two of these transporters, called afuapc and afazga, were found responsible for bulk uptake of purines and studied in detail herein. genetic knock-out analysis, regulation of transcription, direct purine uptake assays and heterologous expression in a. nidulans have unequivoca ...200817881254
isolation of aspergillus nidulans from a case of fungal rhinosinusitis: a case report.a rare species i.e. a. nidulans is reported as a causative agent of allergic fungal rhinosinusitis in this study. it is an increasingly recognized type of chronic recurring hypertrophic sinus disease. there are more than 185 species of aspergillus and over 95% of all infections are caused by a. fumigatus, a. flavus and a. niger. a. fumigatus alone accounts for the large majority of cases of both invasive and non invasive aspergillosis. a young immunocompetent lady presented with bilateral nasal ...200717883183
napa and napb are the aspergillus nidulans nap/set family members and napb is a nuclear protein specifically interacting with importin eukaryotic cells, importin alpha is the major carrier for transport protein cargoes into the nucleus. we characterize here kapa, the single aspergillus nidulans gene encoding an importin alpha. using an affinity approach, we identify six potential interactors of kapa(50), a deleted version of kapa lacking the autoinhibitory importin-beta-binding domain. one such interactor is napb, the a. nidulans orthologue of saccharomyces cerevisiae vps75p, a histone chaperone member of the nap/set family ...200817890114
aspergillus volatiles regulate aflatoxin synthesis and asexual sporulation in aspergillus parasiticus.aspergillus parasiticus is one primary source of aflatoxin contamination in economically important crops. to prevent the potential health and economic impacts of aflatoxin contamination, our goal is to develop practical strategies to reduce aflatoxin synthesis on susceptible crops. one focus is to identify biological and environmental factors that regulate aflatoxin synthesis and to manipulate these factors to control aflatoxin biosynthesis in the field or during crop storage. in the current stu ...200717890344
identification of dioxygenases required for aspergillus development. studies of products, stereochemistry, and the reaction mechanism.aspergillus sp. contain ppoa, ppob, and ppoc genes, which code for fatty acid oxygenases with homology to fungal linoleate 7,8-diol synthases (7,8-lds) and cyclooxygenases. our objective was to identify these enzymes, as ppo gene replacements show critical developmental aberrancies in sporulation and pathogenicity in the human pathogen aspergillus fumigatus and the genetic model aspergillus nidulans. the ppoas of a. fumigatus and a. nidulans were identified as (8r)-dioxygenases with hydroperoxid ...200717906293
evidence for the direct involvement of the proteasome in the proteolytic processing of the aspergillus nidulans zinc finger transcription factor pacc.the 72-kda zinc finger transcription factor pacc, distantly related to ci/gli developmental regulators, undergoes two-step proteolytic processing in response to alkaline ambient ph. "signaling protease" cleavage of pacc(72) removes a processing-inhibitory c-terminal domain, making its truncated pacc(53) product accessible to a second "processing" protease, yielding pacc(27). features of the processing proteolysis suggested the proteasome as a candidate protease. we constructed, using gene replac ...200717911112
a novel regulator couples sporogenesis and trehalose biogenesis in aspergillus nidulans.trehalose is a compatible osmolyte produced by bacteria, fungi, insects and plants to protect the integrity of cells against various environmental stresses. spores, the reproductive, survival and infection bodies of fungi require high amounts of trehalose for long-term survival. here, via a gain-of-function genetic screen, we identify the novel regulator vosa that couples the formation of spores and focal trehalose biogenesis in the model fungus aspergillus nidulans. the vosa gene is expressed s ...200717912349
self-fertility: the genetics of sex in lonely fungi.the genome of the fungus aspergillus nidulans encodes both of the mating-type regulators of sexuality, thus allowing self-fertility. pheromone signaling genes are induced during sexual development, as found in outcrossing species, but, surprisingly, the regulators do not control expression of these genes.200717925212
in vitro analysis of his-asp phosphorelays in aspergillus nidulans: the first direct biochemical evidence for the existence of his-asp phosphotransfer systems in filamentous fungi.his-asp phosphorelays are widespread signal transduction mechanisms in bacteria, fungi, and higher plants. in order to investigate a his-asp phosphorelay network in filamentous fungi, which has been genetically characterized in part, we attempted to construct an in vitro phosphotransfer network in aspergillus nidulans comprising all the necessary components. as a first step, we established an in vitro phosphotransfer system with a histidine-containing phosphotransmitter ypda, a response regulato ...200717928704
time fluctuations and imaging in the sers spectra of fungal hypha grown on nanostructured substrates.surface-enhanced raman scattering (sers) spectroscopy is an emerging technique in biomolecular analysis that can have a tremendous impact in the life sciences. we report on the sers imaging of fungal hyphae grown on nanostructured sers active substrates engineered using semiconductor technologies. time fluctuations in the intensity and band position in the sers spectra measured on the same sample position with 1 s integration time have been observed indicating that the sers signal arises from a ...200717944510
in vitro susceptibilities of aspergillus spp. causing otomycosis to amphotericin b, voriconazole and itraconazole.otomycosis is worldwide in distribution and most commonly caused by aspergillus species. amphotericin b, itraconazole and voriconazole are used for the treatment of aspergillosis, but recently an increase in resistance to these agents has been reported. we aimed at investigating the in vitro activities of amphotericin b, voriconazole and itraconazole against aspergillus isolates causing otomycosis. mycological analysis of samples from the ear canals of patients was performed by culturing onto sa ...200717944704
establishment of the ambient ph signaling complex in aspergillus nidulans: pali assists plasma membrane localization of palh.the aspergillus nidulans ambient ph signaling pathway involves two transmembrane domain (tmd)-containing proteins, palh and pali. we provide in silico and mutational evidence suggesting that pali is a three tmd (3-tmd) protein with an n-terminal signal peptide, and we show that pali localizes to the plasma membrane. pali is not essential for the proteolytic conversion of the pacc translation product into the processed 27-kda form, but its absence markedly reduces the accumulation of the 53-kda i ...200717951518
the penicillium chrysogenum antifungal protein paf, a promising tool for the development of new antifungal therapies and fungal cell biology recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due to their potential to prevent and combat microbial infections in all areas of life. a detailed knowledge about the function of such proteins is the most important requirement to consider them for future application. our research in recent years has been focused on the low molecular weight, cysteine-rich and cationic antifungal protein paf from penicillium chrysogenum, whic ...200817965829
transcriptional regulation of genes on the non-syntenic blocks of aspergillus oryzae and its functional relationship to solid-state cultivation.transcriptome analysis revealed close relationship between solid-state cultivation and the transcriptional regulation of the genes on the non-syntenic blocks (nsbs), which were characterized by the comparison of aspergillus oryzae genome with those of aspergillus fumigatus and aspergillus nidulans. average expression ratio of the genes on nsbs in solid-state cultivation was significantly higher than that on the syntenic blocks (sbs). of the induced genes, the genes relating to metabolism, which ...200817967552
isolation of four pepsin-like protease genes from aspergillus niger and analysis of the effect of disruptions on heterologous laccase expression.four new aspartic protease genes pepaa, pepab, pepac and pepad from aspergillus niger were identified using a comparative genomic approach. all four gene products have highly conserved attributes that are characteristic of aspartic proteases; however, each one has novel sequence features. the pepaa protease appears to represent an ortholog of a pepsin-type aspartic protease previously identified from talaromyces emersonii and scleotinia sclerotiorum. the pepab protease appears to be an ortholog ...200817977034
the aspergillus nidulans esdc (early sexual development) gene is necessary for sexual development and is controlled by vea and a heterotrimeric g protein.the esdc (early sexual development) gene was isolated by using an expressed sequence tag (est) as a probe from a genomic library of the early sexual developmental stage mycelia of aspergillus nidulans. the sequence analysis revealed that the esdc gene contains a 59bp intron and encodes a 266 amino acid polypeptide with a calculated molecular weight of 29.4kda. the esdc protein is conserved among filamentous fungi and has a domain with similarity to a glycogen binding domain conserved in the beta ...200817977758
the neurospora crassa uvs-3 epistasis group encodes homologues of the atr/atrip checkpoint control system.the mutagen sensitive uvs-3 and mus-9 mutants of neurospora show mutagen and hydroxyurea sensitivity, mutator effects and duplication instability typical of recombination repair and dna damage checkpoint defective mutants. to determine the nature of these genes we used cosmids from a genomic library to clone the uvs-3 gene by complementation for mms sensitivity. mutation induction by transposon insertion and rip defined the coding sequence. rflp analysis confirmed that this sequence maps in the ...200817983847
copa:gfp localizes to putative golgi equivalents in aspergillus nidulans.the golgi complex is a main component of the eukaryotic secretory system and functions to modify nascent proteins sent from the endoplasmic reticulum. ultrastructural studies of filamentous fungi have shown golgi to be individual smooth membrane cisternae that are referred to as golgi equivalents or dictyosomes. the aspergillus nidulans copa gene encodes a homolog of mammalian coat protein (alpha-cop), a constituent of the golgi-localized copi vesicle coat. here, the localization of a. nidulansa ...200717986089
a protein kinase c-encoding gene, pkca, is essential to the viability of the filamentous fungus aspergillus nidulans.a protein kinase c (pkc)-encoding gene (pkca) was isolated from the filamentous fungus aspergillus nidulans. although we attempted to isolate pkca deletion mutants, we obtained only heterokaryons that had both deltapkca and pkca(+) nuclei. conidia produced by the heterokaryon germinated. the germ tubes, however, lysed frequently and no colony formation was observed, indicating that the pkca gene is essential to the viability of a. nidulans. we constructed conditional mutants (alca(p)-pkca mutant ...200717986778
basic-zipper-type transcription factor flbb controls asexual development in aspergillus nidulans.the fungal colony is a complex multicellular unit consisting of various cell types and functions. asexual spore formation (conidiation) is integrated through sensory and regulatory elements into the general morphogenetic plan, in which the activation of the transcription factor brla is the first determining step. a number of early regulatory elements acting upstream of brla (flug and flba-e) have been identified, but their functional relations remain to be further investigated. in this report we ...200817993569
expression of the fluorescence markers dsred and gfp fused to a nuclear localization signal in the arbuscular mycorrhizal fungus glomus, arbuscular mycorrhizal (am) fungi were monitored in vivo introducing the fluorescent reporters dsred and gfp (green fluorescent protein) in glomus intraradices using a biolistic approach and agrobacterium tumefaciens-mediated transformation. both reporter genes were fused to the nuclear localization signal of the aspergillus nidulans transcription factor stua to target fluorescence to nuclei. expression of dsred was driven by two glomus mosseae promoters highly expressed during early symbi ...200817995919
apical sterol-rich membranes are essential for localizing cell end markers that determine growth directionality in the filamentous fungus aspergillus filamentous fungi, hyphal extension depends on the continuous delivery of vesicles to the growing tip. here, we describe the identification of two cell end marker proteins, teaa and tear, in aspergillus nidulans, corresponding to tea1 and mod5 in schizosaccharomyces pombe. deletion of teaa or tear caused zig-zag-growing and meandering hyphae, respectively. the kelch-repeat protein teaa, the putatively prenylated tear protein, and the formin sepa were highly concentrated in the spitzenkörper, ...200818003978
regulation of hyphal morphogenesis by cdc42 and rac1 homologues in aspergillus nidulans.the ability of filamentous fungi to form hyphae requires the establishment and maintenance of a stable polarity axis. based on studies in yeasts and animals, the gtpases cdc42 and rac1 are presumed to play a central role in organizing the morphogenetic machinery to enable axis formation and stabilization. here, we report that cdc42 (moda) and rac1 (raca) share an overlapping function required for polarity establishment in aspergillus nidulans. nevertheless, cdc42 appears to have a more important ...200718005099
nitrite transport is mediated by the nitrite-specific high-affinity nita transporter and by nitrate transporters nrta, nrtb in aspergillus nidulans.disruption of the aspergillus nidulans high-affinity nitrate transporter genes (nrta and nrtb) prevents growth on nitrate but not nitrite. we identified a distinct nitrite transporter (k(m)=4.2+/-1 microm, v(max)=168+/-21 nmolmg(-1)dw(-1)h(-1)), designated nita. disruption of nrta, nrtb and nita blocked growth on nitrite, despite low rates of nitrite depletion we ascribe to passive nitrous acid permeation. growth of the single mutant nita16 on nitrite was wild-type, suggesting that nrta and/or n ...200818024100
the aspergillus nidulans enzyme tdib catalyzes prenyltransfer to the precursor of bioactive asterriquinones.the asterriquinones represent a class of ascomycete metabolic products whose significance stems from remarkable and useful pharmacological activities, among those antiretroviral (e.g., against the hi-virus), antitumor, and antidiabetes properties. recently, the first genetic locus for an asterriquinone, the clustered terrequinone genes tdia-e, was identified during a genome-wide screen in aspergillus nidulans for "orphan" natural product biosynthesis loci. here, we describe overexpression and ch ...200818029206
overexpression of the plg1 gene encoding pectin lyase in penicillium griseoroseum.the pectin lyase (pl) is an industrially important enzyme since it is used for maceration and clarification in the process of fruit juice production in food industries. in order to increase the yields of pectin lyase we cloned the plg1 (pectin lyase 1) from penicillium griseoroseum gene under the control of the strong constitutive promoter of the glyceraldehyde-3-phosphate dehydrogenase gene (gpda) and the terminator region of the tryptophan synthetase (trpc) gene from aspergillus nidulans (plas ...200818030511
characterization of active site variants of xanthine hydroxylase from aspergillus nidulans.xanthine/alpha-ketoglutarate (alphakg) dioxygenase (xana) is a non-heme mononuclear fe(ii) enzyme that decarboxylates alphakg to succinate and co(2) while hydroxylating xanthine to generate uric acid. in the absence of a xana crystal structure, a homology model was used to target several putative active site residues for mutagenesis. wild-type xana and ten enzyme variants were purified from recombinant escherichia coli cells and characterized. the h149a and d151a variants were inactive and the h ...200818036331
improved protocols for functional analysis in the pathogenic fungus aspergillus available whole genome sequence for aspergillus flavus provides the opportunity to characterize factors involved in pathogenicity and to elucidate the regulatory networks involved in aflatoxin biosynthesis. functional analysis of genes within the genome is greatly facilitated by the ability to disrupt or mis-express target genes and then evaluate their result on the phenotype of the fungus. large-scale functional analysis requires an efficient genetic transformation system and the ability to ...200718039373
ras gtpase-activating protein regulation of actin cytoskeleton and hyphal polarity in aspergillus nidulans.aspergillus nidulans gapa1, a mutation leading to compact, fluffy colonies and delayed polarity establishment, maps to a gene encoding a ras gtpase-activating protein. domain organization and phylogenetic analyses strongly indicate that gapa regulates one or more "true" ras proteins. a gapadelta strain is viable. gapa colonies are more compact than gapa1 colonies and show reduced conidiation. gapadelta strains have abnormal conidiophores, characterized by the absence of one of the two layers of ...200818039943
identification of nutrient-dependent changes in extracellular ph and acid phosphatase secretion in aspergillus nidulans.the present study was designed to identify nutrient-dependent changes in extracellular ph and acid phosphatase secretion in the bia1 palc4 mutant strain of aspergillus nidulans. the palc4 mutant was selected as lacking alkaline phosphatase, but having substantially increased acid phosphatase activity when grown on solid minimal medium under phosphate starvation, ph 6.5. gene palc was identified as a putative member of a conserved signaling cascade involved in ambient alkaline sensing whose sole ...200718050093
Displaying items 3601 - 3700 of 5149