the pho80-like cyclin of aspergillus nidulans regulates development independently of its role in phosphate saccharomyces cerevisiae, phosphate acquisition enzymes are regulated by a cyclin-dependent kinase (pho85), a cyclin (pho80), the cyclin-dependent kinase inhibitor pho81, and the helix-loop-helix transcription factor pho4 (the pho system). previous studies in aspergillus nidulans indicate that a pho85-like kinase, phoa, does not regulate the classic pho system but regulates development in a phosphate-dependent manner. a pho80-like cyclin has now been isolated through its interaction with phoa ...200415247298
a role for cred, a carbon catabolite repression gene from aspergillus nidulans, in aspergillus nidulans, it is known that creb encodes a deubiquitinating enzyme that forms a complex with the wd40 motif containing protein encoded by crec, that mutations in these genes lead to altered carbon source utilization and that the cred34 mutation suppresses the phenotypic effects of mutations in crec and creb. therefore, cred was characterized in order to dissect the regulatory network that involves the creb-crec deubiquitination complex. cred contains arrestin domains and py motifs ...200415255903
physiological and morphological changes in autolyzing aspergillus nidulans cultures.physiological and morphological changes in carbon-limited autolyzing cultures of aspergillus nidulans were described. the carbon starvation arrested conidiation while the formation of filamentous and "yeast-like" hyphal fragments with profoundly altered metabolism enabled the fungus to survive the nutritional stress. the morphological and physiological stress responses, which maintained the cellular integrity of surviving hyphal fragments at the expense of autolyzing cells, were highly concerted ...200415259768
on the mechanism of action of the antifungal agent propionate.propionate is used to protect bread and animal feed from moulds. the mode of action of this short-chain fatty acid was studied using aspergillus nidulans as a model organism. the filamentous fungus is able to grow slowly on propionate, which is oxidized to acetyl-coa via propionyl-coa, methylcitrate and pyruvate. propionate inhibits growth of a. nidulans on glucose but not on acetate; the latter was shown to inhibit propionate oxidation. when grown on glucose a methylcitrate synthase deletion mu ...200415265042
the ganb galpha-protein negatively regulates asexual sporulation and plays a positive role in conidial germination in aspergillus nidulans.we isolated the ganb gene encoding the galpha-protein homolog from aspergillus nidulans. to investigate the cellular function of ganb, various mutant strains were isolated. deletion of constitutively inactive ganb mutants showed conidiation and derepressed brla expression in a submerged culture. constitutive activation of ganb caused a reduction in hyphal growth and a severe defect in asexual sporulation. we therefore propose that ganb may negatively regulate asexual sporulation through the brla ...200415280244
molecular cloning and characterization of a cdna encoding the n-acetyl-beta-d-glucosaminidase homologue of paracoccidioides brasiliensis.a cdna encoding the n-acetyl-beta-d-glucosaminidase (nag) protein of paracoccidioides brasiliensis, pb nag1, was cloned and characterized. the 2663-nucleotide sequence of the cdna consisted of a single open reading frame encoding a protein with a predicted molecular mass of 64.73 kda and an isoeletric point of 6.35. the predicted protein includes a putative 30-amino-acid signal peptide. the protein as a whole shares considerable sequence similarity with 'classic' nag. the primary sequence of pb ...200415283239
vea is required for toxin and sclerotial production in aspergillus was long been noted that secondary metabolism is associated with fungal development. in aspergillus nidulans, conidiation and mycotoxin production are linked by a g protein signaling pathway. also in a. nidulans, cleistothecial development and mycotoxin production are controlled by a gene called vea. here we report the characterization of a vea ortholog in the aflatoxin-producing fungus a. parasiticus. cleistothecia are not produced by aspergillus parasiticus; instead, this fungus produces sp ...200415294809
rapid differentiation of aspergillus species from other medically important opportunistic molds and yeasts by pcr-enzyme immunoassay.we developed a pcr-based assay to differentiate medically important species of aspergillus from one another and from other opportunistic molds and yeasts by employing universal, fungus-specific primers and dna probes in an enzyme immunoassay format (pcr-eia). oligonucleotide probes, directed to the internal transcribed spacer 2 region of ribosomal dna from aspergillus flavus, aspergillus fumigatus, aspergillus nidulans, aspergillus niger, aspergillus terreus, aspergillus ustus, and aspergillus v ...200415297489
the metarhizium anisopliae trp1 gene: cloning and regulatory analysis.the trp1 gene from the entomopathogenic fungus metarhizium anisopliae, cloned by heterologous hybridization with the plasmid carrying the trpc gene from aspergillus nidulans, was sequence characterized. the predicted translation product has the conserved catalytic domains of glutamine amidotransferase (g domain), indoleglycerolphosphate synthase (c domain), and phosphoribosyl anthranilate isomerase (f domain) organized as nh2-g-c-f-cooh. the orf is interrupted by a single intron of 60 nt that is ...200415297933
isocitrate lyase from aspergillus nidulans: crystallization and x-ray analysis of a glyoxylate cycle enzyme.isocitrate lyase (icl) from the filamentous fungus aspergillus nidulans catalyzes the first committed step of the carbon-conserving glyoxylate bypass. this enzyme has been crystallized by the hanging-drop method of vapour diffusion using polyethylene glycol 2000 as the precipitant. diffraction patterns show that the crystals diffract to beyond 2.5 a and are probably in space group p4(2)2(1)2 with unit-cell dimensions of a = b = 91.9 and c = 152.7 a, with one molecule in the asymmetric unit. the ...199715299923
effect of ph on the stability of pleurotus eryngii versatile peroxidase during heterologous production in emericella nidulans.complementary dna (cdna) encoding the new versatile peroxidase from the ligninolytic basidiomycete pleurotus eryngii has been expressed in the ascomycete emericella nidulans. in recombinant e. nidulans cultures, the ph reached values as high as 8.3, correlating with a sharp decrease in peroxidase activity. peroxidase was rapidly inactivated at alkaline ph, but was comparatively stable at acidic ph. the peroxidase inactivation in alkaline buffer could be reversed by adding ca(2+) and lowering the ...200415300480
chpa, a cysteine- and histidine-rich-domain-containing protein, contributes to maintenance of the diploid state in aspergillus nidulans.the alternation of eukaryotic life cycles between haploid and diploid phases is crucial for maintaining genetic diversity. in some organisms, the growth and development of haploid and diploid phases are nearly identical, and one might suppose that all genes required for one phase are likely to be critical for the other phase. here, we show that targeted disruption of the chpa (cysteine- and histidine-rich-domain- [chord]-containing protein a) gene in haploid aspergillus nidulans strains gives ri ...200415302831
prp8 intein in fungal pathogens: target for potential antifungal drugs.inteins are self-splicing intervening sequences in proteins, and inteins of pathogenic organisms can be attractive drug targets. here, we report an intein in important fungal pathogens including aspergillus fumigatus, aspergillus nidulans, histoplasma capsulatum, and different serotypes of cryptococcus neoformans. this intein is inside the extremely conserved and functionally essential prp8 protein, and it varies in size from 170 aa in c. neoformans to 819 aa in a. fumigatus, which is caused by ...200415304322
effect of vitamin e on autolysis and sporulation of aspergillus nidulans.the morphologic and physiologic effects of vitamin e, a powerful antioxidant, on the autolysis and sporulation of aspergillus nidulans fgsc26 were studied. in carbon-depleted submerged cultures, reactive oxygen species (ros) accumulated in the cells and, concomitantly, progressing autolysis was observed, which was characterized by decreasing dry cell masses and pellet diameters as well as by increasing extracellular chitinase activities. vitamin e supplemented at a concentration of 1 g/l hindere ...200415304761
influence of fadag203r and deltaflba mutations on morphology and physiology of submerged aspergillus nidulans cultures.morphologic and physiologic changes taking place in carbon-limited submerged cultures of aspergillus nidulans deltaflba and fadag203r strains were studied. loss-of-function mutation of the flba gene resulted in an altered germination with unusually thick germination tubes, "fluffy" pellet morphology, as well as a reduced fragmentation rate of hyphae during autolysis. in the fadag203r mutant strain, conidiophores formed in the stationary phase of growth, and the size of pellets shrank considerabl ...200415304762
histone methyltransferases in aspergillus nidulans: evidence for a novel enzyme with a unique substrate specificity.we have studied enzymes involved in histone arginine methylation in the filamentous fungus aspergillus nidulans. three distinct protein arginine methyltransferases (prmts) could be identified, which all exhibit intrinsic histone methyltransferase activity when expressed as glutathione s-transferase (gst) fusion proteins. two of these proteins, termed rmta (arginine methyltransferase a) and rmtc, reveal significant sequence homology to the well-characterized human proteins prmt1 and prmt5, respec ...200415311944
an appropriate increase in the transcription of aspergillus nidulans uvsc improved gene targeting efficiency.gene targeting to knock out the activity of specific genes has become important due to recent progress in genomics research. but this technique is still unavailable for many organisms, including economically important microorganisms, due to the high background of ectopic integration during genetic transformation. strategies to improve targeting efficiency have included manipulating the expression of genes that are involved in homologous recombination. in this study, transcription of aspergillus ...200415322347
unprecedented mechanism of chain length determination in fungal aromatic polyketide synthases.fungal aromatic polyketides show remarkable structural diversity fundamentally derived from variations in chain length and cyclization pattern. their basic skeletons are synthesized by multifunctional iterative type i polyketide synthases (pkss). recently, we have found that the c-terminal thioesterase (te)-like domain of aspergillus nidulans wa catalyzes claisen-type cyclization to form the b-ring of naphthopyrone ywa1. here we report the unprecedented mechanism of chain length determination by ...200415324811
a single subunit of a heterotrimeric ccaat-binding complex carries a nuclear localization signal: piggy back transport of the pre-assembled complex to the unresolved question concerns the nuclear localization of the heterotrimeric ccaat-binding complex, which is evolutionarily conserved in eukaryotic organisms including fungi, plants and mammals. all three subunits are necessary for dna binding. in the filamentous fungus aspergillus nidulans the corresponding complex was designated ancf (a.nidulans ccaat-binding factor). ancf consists of the hapb, hapc and hape subunits. here, by using various green fluorescent protein constructs, a nuclear loc ...200415327951
identification and characterization of a novel delta12-fatty acid desaturase gene from rhizopus arrhizus.based on the sequence information of delta12-fatty acid desaturase genes (from mucor circinelloides, mortierella alpina, mucor rouxii and aspergillus nidulans), which were involved in the conversion from c18:1 to c18:2, a cdna sequence putatively encoding a delta12-fatty acid desaturase was isolated from rhizopus arrhizus using the combination of reverse transcription-polymerase chain reaction (rt-pcr) and rapid amplification of cdna ends (race) methods. sequence analysis indicated that it had a ...200415327973
terbinafine resistance mediated by salicylate 1-monooxygenase in aspergillus nidulans.resistance to antifungal agents is a recurring and growing problem among patients with systemic fungal infections. uv-induced aspergillus nidulans mutants resistant to terbinafine have been identified, and we report here the characterization of one such gene. a sib-selected, 6.6-kb genomic dna fragment encodes a salicylate 1-monooxygenase (sala), and a fatty acid synthase subunit (fasc) confers terbinafine resistance upon transformation of a sensitive strain. subfragments carrying sala but not f ...200415328121
the gpra and gprb genes encode putative g protein-coupled receptors required for self-fertilization in aspergillus nidulans.the filamentous fungus aspergillus nidulans possesses both asexual and sexual reproductive cycles. sexual fruiting bodies (cleistothecia) can be formed in both homothallic (self) and heterothallic (outcross) conditions. in this study, we characterized two genes, gpra and gprb, that are predicted to encode putative g protein-coupled receptors (gpcrs) similar to fungal pheromone receptors. deletion (delta) of gpra or gprb resulted in the production of a few small cleistothecia carrying a reduced n ...200415341643
the aspergillus nidulans npka gene encodes a cdc2-related kinase that genetically interacts with the uvsbatr kinase.the dna damage response is a protective mechanism that ensures the maintenance of genomic integrity. we have used aspergillus nidulans as a model system to characterize the dna damage response caused by the antitopoisomerase i drug, camptothecin. we report the molecular characterization of a p34cdc2-related gene, npka, from a. nidulans. the npka gene is transcriptionally induced by camptothecin and other dna-damaging agents, and its induction in the presence of camptothecin is dependent on the u ...200415342504
characterization of the aspergillus parasiticus delta12-desaturase gene: a role for lipid metabolism in the aspergillus-seed the mycotoxigenic oilseed pathogens aspergillus flavus and aspergillus parasiticus and the model filamentous fungus aspergillus nidulans, unsaturated fatty acids and their derivatives act as important developmental signals that affect asexual conidiospore, sexual ascospore and/or sclerotial development. to dissect the relationship between lipid metabolism and fungal development, an a. parasiticus delta(12)-desaturase mutant that was unable to convert oleic acid to linoleic acid and was thus i ...200415347747
the role of thiol species in the hypertolerance of aspergillus sp. p37 to arsenic.aspergillus sp. p37 is an arsenate-hypertolerant fungus isolated from a river in spain with a long history of contamination with metals. this strain is able to grow in the presence of 0.2 m arsenate, i.e. 20-fold higher than the reference strain, aspergillus nidulans ts1. although aspergillus sp. p37 reduces as(v) to as(iii), which is slowly pumped out of the cell, the measured efflux of oxyanions is insufficient to explain the high tolerance levels of this strain. to gain an insight into this p ...200415364940
efficient gene disruption in the koji-mold aspergillus sojae using a novel variation of the positive-negative method.when no phenotypic screen is available, gene disruption in the koji-mold aspergillus sojae is a time-consuming process, owing to the low frequency of homologous recombination. to achieve efficient gene disruption in the koji-mold, we developed a novel positive-negative selection method to enrich for homologous recombinants. the pyrg gene from a. sojae was used as a positive selection marker for transformants, and the olic31 gene of a. nidulans, which codes for a mutant form of subunit 9 of the f ...200415375695
functional analysis of the homoserine o-acetyltransferase gene and its identification as a selectable marker in gibberella zeae.we used restriction enzyme-mediated integration (remi) to identify a methionine auxotrophic mutant of gibberella zeae, an important cereal pathogen. in addition to its methionine requirement, the g. zeae remi mutant designated z43r3912 showed pleiotropic phenotypes, including reduced virulence on host plants and lack of sexual development. outcrossing of z43r3912 with a mat1-1 deletion strain confirmed that the mutation of z43r3912 was tagged with the hygromycin b resistance marker. the vector i ...200415378266
inhibitors of types i and ii dehydroquinase.inhibitors of varying potency have been developed for types i and ii 3-dehydroquinate dehydratase (dehydroquinase), enzymes from the shikimate and quinate pathways that catalyse the dehydration of dehydroquinate to dehydroshikimate. these inhibitors have resulted from enzyme mechanistic studies and from the direct search for enzyme inhibitors with herbicidal, fungicidal or antimicrobial potential. this review discusses the design of the various inhibitors that have been produced so far and some ...200415379642
unique biosynthesis of dehydroquinic acid?a search of the genomic sequences of the thermophilic microorganisms aquifex aeolicus, archaeoglobus fulgidus, methanobacterium thermoautotrophicum, and methanococcus jannaschii for the first seven enzymes (arog, b, d, e, k, a, and c ) involved in the shikimic acid biosynthetic pathway reveal two key enzymes are missing. the first enzyme in the pathway, 3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthase (arog) and the second enzyme in the pathway, 5-dehydroquinic acid synthase (arob) are " ...200415381397
multi-copy suppression of an aspergillus nidulans mutant sensitive to camptothecin by a putative monocarboxylate transporter.the mono carboxylate transporter (mct) is a family of membrane proteins from the major facilitator superfamily (mfs) of transporters. here, we report the first identified aspergillus nidulans mct homologue, amca. the amca gene was isolated by high copy number suppression of the hydroxyurea (hu) sensitivity of an a. nidulans camptothecin-sensitive mutant. expression of amca is increased when hyphae are grown in media containing acetate or pyruvate as single carbon source, and after exposure to se ...200415386109
[pathogenic power of aspergillus nidulans under experimental conditions]. 195015424397
combining transcriptome data with genomic and cdna sequence alignments to make confident functional assignments for aspergillus nidulans genes.whole genome sequencing of several filamentous ascomycetes is complete or in progress; these species, such as aspergillus nidulans, are relatives of saccharomyces cerevisiae. however, their genomes are much larger and their gene structure more complex, with genes often containing multiple introns. automated annotation programs can quickly identify open reading frames for hypothetical genes, many of which will be conserved across large evolutionary distances, but further information is required t ...200415449589
[rgs proteins (regulators of g protein signaling) and their roles in regulation of immune response].rgs proteins (regulators of g-protein signaling) comprise a protein family responsible for regulating g proteins. by enhancing the gtpase activity of the a subunit, they speed up the reconstruction of the heterotrimeric structure of g protein, thus inhibiting its signal transduction. sst2 protein in yeast saccharomyces cervisiae, flba in fungus aspergillus nidulans, and egl-10 in the nematode caenorhabditis elegans are the first native g regulators with gtpase activity (gaps:--gtpase-activating ...200415459549
comparison of ligand-induced conformational changes and domain closure mechanisms, between prokaryotic and eukaryotic dehydroquinate synthases.dehydroquinate synthase (dhqs) is a potential target for the development of novel broad-spectrum antimicrobial drugs, active against both prokaryotes and lower eukaryotes. structures have been reported for aspergillus nidulans dhqs (andhqs) in complexes with a range of ligands. analysis of these andhqs structures showed that a large-scale domain movement occurs during the normal catalytic cycle, with a complex series of structural elements propagating substrate binding-induced conformational cha ...200415465043
double-joint pcr: a pcr-based molecular tool for gene manipulations in filamentous fungi.gene replacement via homologous double crossover in filamentous fungi requires relatively long (preferentially >0.5 kb) flanking regions of the target gene. for this reason, gene replacement cassettes are usually constructed through multiple cloning steps. to facilitate gene function studies in filamentous fungi avoiding tedious cloning steps, we have developed a pcr-assisted dna assembly procedure and applied it to delete genes in filamentous fungi. while the principle of this procedure is esse ...200415465386
identification and complementation of abnormal hyphal branch mutants ahba1 and ahbb1 in aspergillus nidulans.branching generates new axes of polar growth in filamentous fungi and is critical for development, reproduction, and pathogenicity. to investigate branching we screened an aspergillus nidulans temperature-sensitive mutant collection for abnormal hyphal branch (ahb) mutants. we identified two mutants, ahba1, which showed reduced branching relative to wild type at restrictive temperature, and ahbb1, which showed increased branching relative to wild type at restrictive temperature. both mutants als ...200415465388
the aspergillus fumigatus cell wall is organized in domains that are remodelled during polarity establishment.aspergillus fumigatus is a life-threatening and increasingly frequent pathogen of the immunocompromised. like other filamentous fungi a. fumigatus grows in a highly polar manner, adding new cell wall to the apical region of hyphae. mabs were raised against isolated a. fumigatus cell walls. fifteen antibodies bound reproducibly to isolated cell walls in elisas and to the walls of intact cells in immunofluorescence experiments. surprisingly, individual mabs showed distinct patterns of localization ...200415470106
introns and splicing elements of five diverse fungi.genomic sequences and expressed sequence tag data for a diverse group of fungi (saccharomyces cerevisiae, schizosaccharomyces pombe, aspergillus nidulans, neurospora crassa, and cryptococcus neoformans) provided the opportunity to accurately characterize conserved intronic elements. an examination of large intron data sets revealed that fungal introns in general are short, that 98% or more of them belong to the canonical splice site (ss) class (5'gu...ag3'), and that they have polypyrimidine tra ...200415470237
rapid production of gene replacement constructs and generation of a green fluorescent protein-tagged centromeric marker in aspergillus nidulans.a method to rapidly generate gene replacement constructs by fusion pcr is described for aspergillus nidulans. the utility of the approach is demonstrated by green fluorescent protein (gfp) tagging of a. nidulans ndc80 to visualize centromeres through the cell cycle. the methodology makes possible large-scale gfp tagging, promoter swapping, and deletion analysis of a. nidulans.200415470263
a functional screen identifies lateral transfer of beta-glucuronidase (gus) from bacteria to fungi.lateral gene transfer (lgt) from prokaryotes to microbial eukaryotes is usually detected by chance through genome-sequencing projects. here, we explore a different, hypothesis-driven approach. we show that the fitness advantage associated with the transferred gene, typically invoked only in retrospect, can be used to design a functional screen capable of identifying postulated lgt cases. we hypothesized that beta-glucuronidase (gus) genes may be prone to lgt from bacteria to fungi (thought to la ...200515483318
recent advances in the characterization of ambient ph regulation of gene expression in filamentous fungi and yeasts.all microorganisms must adapt to the ph of their environment. one aspect of this adaptation, particularly important for organisms that grow over a wide ph range, is the ability to express appropriately genes whose roles ultimately involve functions at the cell surface or in the environment. genes encoding permeases, secreted enzymes, enzymes involved in synthesis of exported metabolites such as toxins and antibiotics, and probably enzymes modifying secreted proteins posttranslationally all fall ...200415487944
gas-inducible transgene expression in mammalian cells and mice.we describe the design and detailed characterization of a gas-inducible transgene control system functional in different mammalian cells, mice and prototype biopharmaceutical manufacturing. the acetaldehyde-inducible alcr-p(alca) transactivator-promoter interaction of the aspergillus nidulans ethanol-catabolizing regulon was engineered for gas-adjustable transgene expression in mammalian cells. fungal alcr retained its transactivation characteristics in a variety of mammalian cell lines and reve ...200415502819
synthesis and antimicrobial activity of some netropsin analogues.nine novel lexitropsins were synthesized by linking two netropsin-like moieties through three different dicarboxylic acids; 9,10-dihydro-2,7-phenanthrenedicarboxylic acid; [(3-[[(carboxymethyl)amino]carbonyl]benzoyl)amino]acetic acid and indole-2,5-dicarboxylic acid. the netropsin residues were modified by the use of n-isopentylpyrrole, 5-methylthiophene or 5-isopropylthiazole heterocyclic building blocks in place of the usual n-methylpyrrole. the compounds were tested against five gram-positive ...200415505717
connection of propionyl-coa metabolism to polyketide biosynthesis in aspergillus nidulans.propionyl-coa is an intermediate metabolite produced through a variety of pathways including thioesterification of propionate and catabolism of odd chain fatty acids and select amino acids. previously, we found that disruption of the methylcitrate synthase gene, mcsa, which blocks propionyl-coa utilization, as well as growth on propionate impaired production of several polyketides-molecules typically derived from acetyl-coa and malonyl-coa-including sterigmatocystin (st), a potent carcinogen, an ...200415514053
[antibiotic properties of some species of genus aspergillus mich].antibiotic activity screening of some species of genus aspergillus (64 strains) to different test-organisms (gram positive, gram negative, phytopathogenic bacteria and yeasts) has been carried out. the researched strains a. parvulus, a. ochraceus, a. ustus, a. versicolor, a.fumigatus, a. niger, a. deflectus, a. clavatus were characterized by a wide spectrum of antibiotic activity; the strains a. flavipes, a. sydowii, a. terreus, a. flavus, a. nidulans, a. alliaceus, a. fluticulosus were characte ...200415515902
tama interacts with leub, the homologue of saccharomyces cerevisiae leu3p, to regulate gdha expression in aspergillus nidulans.previous studies have shown that expression of the gdha gene, encoding nadp-linked glutamate dehydrogenase (nadp-gdh), in aspergillus nidulans is regulated by the major nitrogen regulatory protein area and its co-activator tama. we show here that loss of tama function has a more severe effect on the levels of gdha expression than loss of area function. using tama as the bait in a yeast two-hybrid screen, we have identified a second protein that interacts with tama. sequencing analysis and functi ...200415517391
regulation of aflatoxin synthesis by fada/camp/protein kinase a signaling in aspergillus parasiticus.analysis of fada and pkaa mutants in the filamentous fungus aspergillus nidulans demonstrated that fada (galpha) stimulates cyclic amp (camp)-dependent protein kinase a (pka) activity resulting, at least in part, in inhibition of conidiation and sterigmatocystin (st) biosynthesis. in contrast, camp added to the growth medium stimulates aflatoxin (af) synthesis in aspergillus parasiticus. our goal was to explain these conflicting reports and to provide mechanistic detail on the role of fada, camp ...200415518351
the zn(ii)2cys6 putative aspergillus nidulans transcription factor repressor of sexual development inhibits sexual development under low-carbon conditions and in submersed we have characterized the putative zn(ii)2cys6 transcription factor rosa from the filamentous fungus aspergillus nidulans. the rosa gene encodes a protein of 713 aa, which shares 38% sequence similarity to pro1 from sordaria macrospora. in contrast to pro1, which promotes the transition from protoperithecia to perithecia, rosa is a negative regulator of sexual development in a. nidulans. transcript levels of rosa were usually very low and were only transiently upregulated upon carbon starva ...200515520269
a phylogenomic approach to reconstructing the diversification of serine proteases in fungi.using a phylogenomic approach with 10 fungi of very different virulence and habitat, we determined that there was substantial diversification of subtilase-type proteases early in ascomycete history (with subsequent loss in many lineages) but with no comparable diversification of trypsins. patterns of intron loss and the degree of divergence between paralogues demonstrated that the proliferation of proteinase k subtilases and subtilisin type subtilases seen in pathogenic ascomycetes (metarhizium ...200415525405
acfkh1, a novel member of the forkhead family, associates with the rfx transcription factor cpcr1 in the cephalosporin c-producing fungus acremonium the filamentous fungus acremonium chrysogenum, a complex regulatory network of transcription factors controls the expression of at least seven cephalosporin c biosynthesis genes. the rfx transcription factor cpcr1 binds to regulatory sequences in the promoter region of cephalosporin c biosynthesis genes, and is involved in the transcriptional regulation of the pcbc gene which encodes isopenicillin n synthase. in this study, we used cpcr1 in a yeast two-hybrid screen to identify potential prot ...200415527986
the fungal stre-element-binding protein seb1 is involved but not essential for glycerol dehydrogenase (gld1) gene expression and glycerol accumulation in trichoderma atroviride during osmotic stress.fungi counteract extracellular osmotic pressure by producing intracellular polyols to prevent loss of water. in yeast osmotic signaling involves a map-kinase pathway culminating at the stre-binding transcription factors msn2/4. we investigated the role of a putative stre-binding orthologue of trichoderma atroviride, seb1, in osmotic stress signaling. t. atroviride, subjected to osmotic stress (10% glucose or glycerol, 1m kcl or nacl), responds by raising its intracellular glycerol level. in cont ...200415531216
modulation of the ligand binding properties of the transcription repressor nmra by gata-containing dna and site-directed mutagenesis.nmra is a negative transcription-regulating protein that binds to the c-terminal region of the gata transcription-activating protein area. the proposed molecular mechanism of action for nmra is to inhibit area binding to its target promoters. in contrast to this proposal, we report that a c-terminal fragment of area can bind individually to gata-containing dna and nmra and that in the presence of a mixture of gata-containing dna and nmra, the area fragment binds preferentially to the gata-contai ...200415537757
missense mutations that inactivate the aspergillus nidulans nrta gene encoding a high-affinity nitrate transporter.the transport of nitrate into prokaryotic and eukaryotic cells, of considerable interest to agriculture, ecology, and human health, is carried out by members of a distinct cluster of proteins within the major facilitator superfamily. to obtain structure/function information on this important class of nitrate permeases, a collection of chemically induced mutations in the nrta gene encoding a 12-transmembrane domain, high-affinity nitrate transporter from the eukaryote aspergillus nidulans was iso ...200515545642
rna silencing in aspergillus nidulans is independent of rna-dependent rna polymerases.the versatility of rna-dependent rna polymerases (rdrps) in eukaryotic gene silencing is perhaps best illustrated in the kingdom fungi. biochemical and genetic studies of schizosaccharomyces pombe and neurospora crassa show that these types of enzymes are involved in a number of fundamental gene-silencing processes, including heterochromatin regulation and rna silencing in s. pombe and meiotic silencing and rna silencing in n. crassa. here we show that aspergillus nidulans, another model fungus, ...200515545645
penicillium chrysogenum glucose oxidase -- a study on its antifungal effects.purification and characterization of the high molecular mass candida albicans-killing protein secreted by penicillium chrysogenum.200415546411
the role of microtubules in rapid hyphal tip growth of aspergillus nidulans.the filamentous fungus aspergillus nidulans grows by polarized extension of hyphal tips. the actin cytoskeleton is essential for polarized growth, but the role of microtubules has been controversial. to define the role of microtubules in tip growth, we used time-lapse microscopy to measure tip growth rates in germlings of a. nidulans and in multinucleate hyphal tip cells, and we used a green fluorescent protein-alpha-tubulin fusion to observe the effects of the antimicrotubule agent benomyl. hyp ...200515548594
mitochondrial beta-oxidation in aspergillus nidulans.beta-oxidation (beta-ox) occurs exclusively in the peroxisomes of saccharomyces cerevisiae and other yeasts, leading to the supposition that fungi lack mitochondrial beta-ox. here we present unequivocal evidence that the filamentous fungus aspergillus nidulans houses both peroxisomal and mitochondrial beta-ox. while growth of a peroxisomal beta-ox disruption mutant (deltafoxa) was eliminated on a very long-chain fatty acid (c(22:1)), growth was only partially impeded on a long-chain fatty acid ( ...200415554960
partial nuclear pore complex disassembly during closed mitosis in aspergillus nidulans.many organisms undergo closed mitosis and locate tubulin and mitotic kinases to nuclei only during mitosis. how this is regulated is unknown. interestingly, the nima kinase of aspergillus nidulans interacts with two nuclear pore complex (npc) proteins and nima is required for mitotic localization of the cdk1 kinase to nuclei. therefore, we wished to define the mechanism by which the npc is regulated during a. nidulans' closed mitosis.200415556859
patterns of intron gain and loss in fungi.little is known about the patterns of intron gain and loss or the relative contributions of these two processes to gene evolution. to investigate the dynamics of intron evolution, we analyzed orthologous genes from four filamentous fungal genomes and determined the pattern of intron conservation. we developed a probabilistic model to estimate the most likely rates of intron gain and loss giving rise to these observed conservation patterns. our data reveal the surprising importance of intron gain ...200415562318
the role of the kinesin motor kipa in microtubule organization and polarized growth of aspergillus nidulans.polarized growth in filamentous fungi requires the integrity of the microtubule (mt) cytoskeleton. we found that growing mts in aspergillus nidulans merge at the center of fast growing tips and discovered that a kinesin motor protein, kipa, related to tea2p of schizosaccharomyces pombe, is required for this process. in a deltakipa strain, mt plus ends reach the tip but show continuous lateral movement. hyphae lose directionality and grow in curves, apparently due to mislocalization of the vesicl ...200515563609
survey of simple sequence repeats in completed fungal genomes.the use of simple sequence repeats or microsatellites as genetic markers has become very popular because of their abundance and length variation between different individuals. ssrs are tandem repeat units of 1 to 6 base pairs that are found abundantly in many prokaryotic and eukaryotic genomes. this is the first study examining and comparing ssrs in completely sequenced fungal genomes. we analyzed and compared the occurrences, relative abundance, relative density, most common, and longest ssrs i ...200515563717
alcohol-mediated haemolysis in yeast.although yeast are generally non-haemolytic, we have found that addition of alcohol vapour confers haemolytic properties on many strains of yeast and other fungi. we have called this phenomenon 'microbial alcohol-conferred haemolysis' (mach). mach is species- and strain-specific: whereas all six candida tropicalis strains tested were haemolytic in the presence of ethanol, none among 10 c. glabrata strains tested exhibited this phenomenon. among 27 c. albicans strains and 11 saccharomyces cerevis ...200415565638
local induction of the alc gene switch in transgenic tobacco plants by acetaldehyde.the alc promoter system, derived from the filamentous fungi aspergillus nidulans, allows chemically regulated gene expression in plants and thereby the study of gene function as well as metabolic and developmental processes. in addition to ethanol, this system can be activated by acetaldehyde, described as the physiological inducer in a. nidulans. here, we show that in contrast to ethanol, acetaldehyde allows tissue-specific activation of the alc promoter in transgenic tobacco plants. soil drenc ...200415574832
a rapid method for promoter exchange in aspergillus nidulans using recombinant pcr.recombinant pcr has been used to generate linear fragments for promoter replacement by transformation in aspergillus nidulans. a cassette vector carrying the pyr-4 non-homologous selectable marker and conditional promoter pr-alca was constructed for use as a template for pcr, and is suitable for testing the function of essential genes. two genes involved in polar growth, cota and bema, were used to assess the system. efficient targeting was possible with both genes using approximately 500bp of f ...200515588991
endogenous lipogenic regulators of spore balance in aspergillus nidulans.the ability of fungi to produce both meiospores and mitospores has provided adaptive advantages in survival and dispersal of these organisms. here we provide evidence of an endogenous mechanism that balances meiospore and mitospore production in the model filamentous fungus aspergillus nidulans. we have discovered a putative dioxygenase, ppoc, that functions in association with a previously characterized dioxygenase, ppoa, to integrate fatty acid derived oxylipin and spore production. in contras ...200415590815
fostua, encoding a basic helix-loop-helix protein, differentially regulates development of three kinds of asexual spores, macroconidia, microconidia, and chlamydospores, in the fungal plant pathogen fusarium oxysporum.the soil-borne fungus fusarium oxysporum causes vascular wilt of a wide variety of plant species. f. oxysporum produces three kinds of asexual spores, macroconidia, microconidia, and chlamydospores. falcate macroconidia are formed generally from terminal phialides on conidiophores and rarely from intercalary phialides on hyphae. ellipsoidal microconidia are formed from intercalary phialides on hyphae. globose chlamydospores with thick walls are developed by the modification of hyphal and conidia ...200415590816
potential link between the nima mitotic kinase and nuclear membrane fission during mitotic exit in aspergillus nidulans.we have isolated tinc as a nima-interacting protein by using the yeast two-hybrid system and have confirmed that tinc interacts with nima in aspergillus nidulans. the tinc-nima interaction is stabilized in the absence of phosphatase inhibitors and in the presence of kinase-inactive nima, suggesting that the interaction is enhanced when nima is not fully activated. tinc is a cytoplasmic protein. tinc homologues and a tinc-like protein (a. nidulans hetc) are conserved in other filamentous fungi. n ...200415590818
susceptibility of filamentous fungi to voriconazole tested by two microdilution methods.the growing number of fungal infections, coupled with emerging resistance to classical antifungal agents, has led to the development of new agents, among them voriconazole. susceptibility to voriconazole was tested by two microdilution techniques: the national committee for clinical laboratory standards reference method m38-a and a colorimetric method, sensititre yeastone. the study tested a total of 244 isolates: 223 aspergillus (136 aspergillus fumigatus, 37 a. niger, 26 a. terreus, 16 a. flav ...200515634979
proper folding of the antifungal protein paf is required for optimal activity.the penicillium chrysogenumantifungal protein paf is secreted into the supernatant after elimination of a preprosequence. paf is actively internalized into the hyphae of sensitive molds and provokes growth retardation as well as changes in morphology. thus far, no information is available on the exact mode of action of paf, nor on the function of its prosequence in protein activity. therefore, we sought to investigate the effects of secreted paf as well as of intracellularly retained pro-paf and ...200515636746
attachment of a histidine tag to the minimal zinc finger protein of the aspergillus nidulans gene regulatory protein area causes a conformational change at the dna-binding site.histidine (his) tags are one of the most popular fusion tags for the isolation of proteins via metal affinity chromatography. the fusion tag is routinely left attached to the protein when carrying out experiments, with the assumption that the addition has no effect on structure or function. in the present study, we have prepared four proteins of the gene regulatory protein area from aspergillus nidulans for crystallization experiments: a 91-amino acid peptide encompassing the minimal dna-binding ...200515642465
doxycycline-regulated gene expression in the opportunistic fungal pathogen aspergillus fumigatus.although aspergillus fumigatus is an important human fungal pathogen there are few expression systems available to study the contribution of specific genes to the growth and virulence of this opportunistic mould. regulatable promoter systems based upon prokaryotic regulatory elements in the e. coli tetracycline-resistance operon have been successfully used to manipulate gene expression in several organisms, including mice, flies, plants, and yeast. however, the system has not yet been adapted fo ...200515649330
nuclear envelope: nuclear pore complexity.a new study shows that the filamentous fungus, aspergillus nidulans, which has a closed mitosis, does not maintain a continuous permeability barrier during mitosis. this work challenges current views of the differences between closed and open mitosis and has implications for understanding mitotic specific changes in the nuclear pore complex and ran gtpase system in lower eukaryotes.200515649347
sepbctf4 is required for the formation of dna-damage-induced uvscrad51 foci in aspergillus nidulans.sepb is an essential, conserved protein required for chromosomal dna metabolism in aspergillus nidulans. homologs of sepb include yeast ctf4p and human hand-1. molecular and bioinformatic characterization of these proteins suggests that they act as molecular scaffolds. furthermore, recent observations implicate the yeast family members in lagging-strand replication and the establishment of sister-chromatid cohesion. here, we demonstrate that sepb functions in the a. nidulans dna damage response. ...200515654119
characterisation of aspergillus niger prolyl aminopeptidase.we have cloned a gene (papa) that encodes a prolyl aminopeptidase from aspergillus niger. homologous genes are present in the genomes of the eurotiales a. nidulans, a. fumigatus and talaromyces emersonii, but the gene is not present in the genome of the yeast saccharomyces cerevisiae. cell extracts of strains overexpressing the gene under the control of its own promoter showed a fourfold to sixfold increase in prolyl aminopeptidase activity, but no change in phenylalanine or leucine aminopeptida ...200515654623
the polo-like kinase plka is required for initiation and progression through mitosis in the filamentous fungus aspergillus nidulans.polo-like kinases (plk) function during multiple stages of mitotic progression and in cytokinesis. we identified and cloned a plk homologue in aspergillus nidulans, plka, which is the first plk reported in a filamentous fungus and the largest member of the plk family to date. as plka was essential, the effects of overexpression and localization of protein in living cells were explored to determine plka function. overexpression of plka permitted hyphal formation, but blocked nuclear division in i ...200515659171
the class v chitin synthase gene csma is crucial for the growth of the chsa chsc double mutant in aspergillus nidulans.chsa and chsc are genes encoding class ii and i chitin synthases of aspergillus nidulans respectively. in a previous study, chsa chsc double mutants showed various growth defects, suggesting that their cell wall architecture was disorganized and their cell wall integrity diminished. here, we constructed chsa chsc chsd triple mutants and chsa chsc csma triple mutants to investigate the role of the class iv and class v chitin synthases, chsd and csma respectively, in maintaining the cell wall stru ...200515665472
expression of a cephalosporin c esterase gene in acremonium chrysogenum for the direct production of deacetylcephalosporin c.a recombinant fungal microorganism capable of producing deacetylcephalosporin c was constructed by transforming a cephalosporin c esterase gene from rhodosporidium toruloides into acremonium chrysogenum. the cephalosporin c esterase gene can be expressed from its endogenous r. toruloides promoter or from the aspergillus nidulans trpc promoter under standard acremonium chrysogenum fermentation conditions. the expression of an active cephalosporin c esterase enzyme in a. chrysogenum results in the ...200415672283
the aspergillus ph-responsive transcription factor pacc regulates virulence.the ability of a pathogen to adapt to the host environment is usually required for the initiation of disease. here we have investigated the importance of the aspergillus nidulans pacc-mediated ph response in the pathogenesis of pulmonary aspergillosis. using mutational analysis, we demonstrate that, in neutropenic mice, elimination of the a. nidulans ph-responsive transcription factor pacc, blocking the ambient ph signal transduction pathway or prevention of pacc proteolytic processing acutely a ...200515686555
ferrichrome in schizosaccharomyces pombe--an iron transport and iron storage compound.schizosaccharomyces pombe has been assumed not to produce siderophores. nevertheless, the genomic sequence of this fission yeast revealed the presence of siderophore biosynthetic genes for hydroxamates. applying a bioassay based on an aspergillus nidulans strain deficient in siderophore biosynthesis, and using reversed-phase hplc and mass spectrometry analysis, we demonstrate that s. pombe excretes and accumulates intracellularly the hydroxamate-type siderophore ferrichrome. under iron-limiting ...200415689108
efficient implementation of a generalized pair hidden markov model for comparative gene finding.the increased availability of genome sequences of closely related organisms has generated much interest in utilizing homology to improve the accuracy of gene prediction programs. generalized pair hidden markov models (gphmms) have been proposed as one means to address this need. however, all gphmm implementations currently available are either closed-source or the details of their operation are not fully described in the literature, leaving a significant hurdle for others wishing to advance the ...200515691859
metabolically independent and accurately adjustable aspergillus sp. expression system.filamentous fungi are well-established expression hosts often used to produce extracellular proteins of use in the food and pharmaceutical industries. the expression systems presently used in aspergillus species rely on either strong constitutive promoters, e.g., that for glyceraldehyde-3-phosphate dehydrogenase, or inducible systems derived from metabolic pathways, e.g., glaa (glucoamylase) or alc (alcohol dehydrogenase). we describe for aspergillus nidulans and aspergillus niger a novel expres ...200515691916
assessment of elasticity and topography of aspergillus nidulans spores via atomic force microscopy.previous studies have described both surface morphology and adhesive properties of fungal spores, but little information is currently available on their mechanical properties. in this study, atomic force microscopy (afm) was used to investigate both surface topography and micromechanical properties of aspergillus nidulans spores. to assess the influence of proteins covering the spore surface, wild-type spores were compared with spores from isogenic roda(+) and roda(-) strains. tapping-mode afm i ...200515691953
[in vitro activity of amphotericin b, itraconazole and voriconazole against 20 species of aspergillus using the sensititre microdilution method].the in vitro activity of antifungal agents against aspergillus has been recently investigated. we studied the susceptibility to amphotericin b, itraconazole and voriconazole of 68 strains belonging to 20 different aspergillus species.200515701327
transformation of fusarium oxysporum by particle bombardment and characterisation of the resulting transformants expressing a gfp transgene.fusarium is the causative agent of a variety of economically significant vascular wilt diseases of vegetables, flowers and field crops. the completion of the first fusarium genome and the availability of an est database now provides a platform for both forward and reverse genetic approaches to ascribe gene function in this phytopathogen. to underpin these strategies effective gene transfer procedures will be required. here we describe an efficient and robust procedure for fusarium oxysporum tran ...200415702267
csma, a class v chitin synthase with a myosin motor-like domain, is localized through direct interaction with the actin cytoskeleton in aspergillus of the essential features of fungal morphogenesis is the polarized synthesis of cell wall components such as chitin. the actin cytoskeleton provides the structural basis for cell polarity in aspergillus nidulans, as well as in most other eukaryotes. a class v chitin synthase, csma, which contains a myosin motor-like domain (mmd), is conserved among most filamentous fungi. the deltacsma null mutant showed remarkable abnormalities with respect to cell wall integrity and the establishment of po ...200515703213
regulation of penicillin biosynthesis in filamentous fungi.the beta-lactam antibiotic penicillin is one of the mainly used antibiotics for the therapy of infectious diseases. it is produced as end product by some filamentous fungi only, most notably by aspergillus (emericella) nidulans and penicillium chrysogenum. the penicillin biosynthesis is catalysed by three enzymes which are encoded by the following three genes: acva (pcbab), ipna (pcbc) and aata (pende). the genes are organised into a gene cluster. although the production of secondary metabolites ...200415719552
cloning and use of sc as homologous marker for aspergillus niger transformation.the sc sequence from aspergillus niger was cloned and developed into a homologous marker system for genetic transformation. the coding region of the sc gene amplified by pcr from the a. niger genome was provided with aspergillus nidulans expression signals (gpda promoter and trpc terminator). this chimeric construct was used to successfully transform a spontaneous sc- isolate of a. niger to prototrophy. the transformants analyzed by southern analysis showed integration of multiple copies of the ...200415722148
development of aspergillus oryzae thia promoter as a tool for molecular biological filamentous fungi, the repertoire of promoters available for exogenous gene expression is limited. here, we report the development and application of the thiamine-regulatable thia promoter (pthia) in aspergillus oryzae as a tool for molecular biological studies. when pthia was used to express the enhanced green fluorescent protein (egfp) reporter, the fluorescence in the mycelia was either repressed or induced in the presence or absence of thiamine in the culture media, respectively. in addit ...200515727819
loss of heterozygosity by mitotic recombination in diploid strain of aspergillus nidulans in response to castor oil plant detergent.somatic recombination in heterozygous diploid cells may be a promotional agent of neoplasms by inducing homozygosity of defective genes. tumor suppressor genes may in this way be completely suppressed in recombinant cells. in this work, the genotoxic effects of detergent derived from the castor oil plant (ricinus communis) in heterozygous diploid cells of aspergillus nidulans are evaluated. previous studies have evaluated the application of this substance in endodontic treatments as an irrigatin ...200415744430
in silico reconstruction of nutrient-sensing signal transduction pathways in aspergillus nidulans.we report here probable nutrient-sensing signal transduction pathways in aspergillus nidulans, a model filamentous fungus, based on sequence homology studies with known saccharomyces cerevisiae and schizosaccharomyces pombe proteins. specifically, we identified a. nidulans homologs for yeast proteins involved in (1) filamentation-invasion, (2) camp-pka, (3) pheromone response, (4) cell integrity and (5) tor signaling pathways. we have also studied autophagy, one of the most important cellular re ...200415752076
[genetic analysis and relationship to pathogenicity in botrytis cinerea].botrytis cinerea is a plant-pathogenic fungus that produces the disease known as grey mould in a wide variety of agriculturally important hosts in many countries. ten strains from different locations collected on different years have been isolated and characterized by several methods (morphological, biochemical, genetical and molecular). results showed that clear morphological differences exist between strains, and showing a relationship between the presence of sclerotia and pathogenicity. the c ...200015762780
[taxonomy and identification of the species involved in nosocomial aspergillosis].although aspergillus fumigatus is the most common etiological agent of invasive aspergillosis, other aspergillus spp. such as a . flavus, a. niger, a. terreus and a. nidulans (emericella nidulans) among others, have been also implicated. in this article, the taxonomy of the genus aspergillus and the characteristics of the species most frequently isolated from patients with nosocomial aspergillosis are reviewed.200015762792
[two cases of scalp wound colonization and respiratory tract by mycelial fungi].one case of colonization of a post-traumatic scalp wound by aspergillus nidulans and fusarium solani in a healthy adult patient is discussed. a second case of respiratory colonization by acrophialophora fusispora in a child with cystic fibrosis is presented. both cases are reported to illustrate the need of combined histologic and mycologic studies in evaluating patients in order to distinguish between colonization and invasion.200015762812
a c-terminal fragment of an intron-encoded maturase is sufficient for promoting group i intron i introns often encode proteins that catalyze site-specific dna hydrolysis. some of these proteins have acquired the ability to promote splicing of their cognate intron, but whether these two activities reside in different regions of the protein remains obscure. a crystal structure of i-anii, a dual function intron-encoded protein, has shown that the protein has two pseudo-symmetric domains of equal size. each domain contacts its dna substrate on either side of two cleavage sites. as a fir ...200515769873
cofactor processing in galactose oxidase.go (galactose oxidase; e.c. is a monomeric 68 kda enzyme that contains a single copper ion and an amino acid-derived cofactor. the enzyme is produced by the filamentous fungus fusarium graminearum as an extracellular enzyme. the enzyme has been extensively studied by structural, spectroscopic, kinetic and mutational approaches that have provided insight into the catalytic mechanism of this radical enzyme. one of the most intriguing features of the enzyme is the post-translational genera ...200415777009
[fatal aspergillus nidulans pneumonia]. 200415777589
evolution of a large ribosomal rna multigene family in filamentous fungi: birth and death of a concerted evolution eukaryotes, the primary components of the ribosome are encoded by multicopy nuclear ribosomal rna (rrna) genes: 28/26s, 18s, 5.8s, and 5s. copies of these genes are typically localized within tandem arrays and homogenized within a genome. as a result, nuclear rrna gene families have become a paradigm of concerted evolution. in filamentous fungi of the subphylum pezizomycotina, 5s rrna genes exist as a large and dispersed multigene family, with between 50 and 100 copies per genome. to determin ...200515784739
genes of the thymidine salvage pathway: thymine-7-hydroxylase from a rhodotorula glutinis cdna library and iso-orotate decarboxylase from neurospora crassa.genes for two enzymes in the thymidine salvage pathway, thymine-7-hydroxylase (thase; official name thymine dioxygenase) and iso-orotate decarboxylase (idcase) have been isolated from fungal sources. thase was isolated from a rhodotorula glutinis cdna library using a degenerate oligonucleotide based on the published amino acid sequence. the coding sequence was transferred to an escherichia coli expression system, from which recombinant thase activity was measured using 14c-labeled thymine. the t ...200515794921
a gene (pks2) encoding a putative 6-methylsalicylic acid synthase from glarea lozoyensis.a gene that encodes for a polyketide synthase (pks) was cloned from the fungus glarea lozoyensis and characterized. the gene (pks2) consists of four exons interrupted by three introns of 51, 59, and 65 bp, which are clustered at the 5' end. its predicted product is a 1791-amino-acid protein containing five catalytic motifs typical of fungal pkss, including a beta-ketosynthase, an acyltransferase, a dehydratase, a beta-ketoacyl reductase, and an acyl carrier region. the gene is transcribed from a ...200515800788
determination of the essentiality of the eight cysteine residues of the nrta protein for high-affinity nitrate transport and the generation of a functional cysteine-less transporter.all eight cysteine residues, c90, c94, c143, c147, c219, c325, c367, and c431, present in transmembrane domains of the aspergillus nidulans nrta nitrate transporter protein were altered individually by site-specific mutagenesis. the results indicate that six residues, c90, c147, c219, c325, c367, and c431, are not required for nitrate transport. although alterations of c94 and c143 are less well tolerated, these residues are not mandatory and their possible role is discussed. a series of constru ...200515807540
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