TitleAbstractYear(sorted descending)
requirement of laea for secondary metabolism and sclerotial production in aspergillus flavus.the nuclear regulator laea has been shown to govern production of multiple secondary metabolites in aspergillus nidulans and aspergillus fumigatus. herein we examine the role of this protein in aspergillus flavus. similarly as in other aspergilli, laea had a major effect on a. flavus secondary metabolism where deltalaea and over-expression laea (oe::laea) strains yielded opposite phenotypes resulting in decreased (increased) secondary metabolite production. the two mutant strains also exhibited ...200818667168
[evolution of meiosis of unicellulate and multicellular eucaryotes. aromorphosis at the cellular level].an attempt was undertaken to apply the concept elaborated for the evolution of multicellular organisms to that of unicellular eucaryotes. the latter's meiosis was formed on the basis of combination on three intracellular processes: 1) homologous dna recombination, 2) chromosome disjunction with the assistance of mitotic apparatus, and 3) formation of "linear" chromosome elements consisting of specific proteins. mechanism of homologous chromosome recombination was inherited from the archibacteria ...200818669302
norsolorinic acid inhibits proliferation of t24 human bladder cancer cells by arresting the cell cycle at the g0/g1 phase and inducing a fas/membrane-bound fas ligand-mediated apoptotic pathway.1. norsolorinic acid, isolated from aspergillus nidulans, has been shown to have antiproliferative activity in t24 human bladder cancer cells by arresting the cell cycle at the g(0)/g(1) phase and inducing apoptosis. the aim of the present study was to investigate the antiproliferative activity of norsolorinic acid in t24 human bladder cancer cells. 2. the effects of norsolorinic acid (1, 5, 10 and 20 micromol/l) on the proliferation of t24 cells and on the distribution of cells within different ...200818671724
dissecting individual steps of nitrogen transcription factor cooperation in the aspergillus nidulans nitrate cluster.summary: in the ascomycete fungus aspergillus nidulans, the transcriptional activation of nitrate assimilating genes (niia, niad) depends on the cooperativity between a general nitrogen status-sensing regulator (the gata factor area) and a pathway-specific activator (the zn-cluster regulator nira). because nitrate assimilation leads to intracellular ammonium formation, it is difficult to determine the individual contributions of nira and area in this complex activation/inactivation process. in a ...200818673441
dissecting colony development of neurospora crassa using mrna profiling and comparative genomics approaches.colony development, which includes hyphal extension, branching, anastomosis, and asexual sporulation, is a fundamental aspect of the life cycle of filamentous fungi; genetic mechanisms underlying these phenomena are poorly understood. we conducted transcriptional profiling during colony development of the model filamentous fungus neurospora crassa, using 70-mer oligonucleotide microarrays. relative mrna expression levels were determined for six sections of defined age excised from a 27-h-old n. ...200818676954
the aspergillus nidulans stress response transcription factor stza is ascomycete-specific and shows species-specific polymorphisms in the c-terminal region.orthologues of the aspergillus nidulans gene stza were identified and characterised in an additional 19 fungi. these orthologues were restricted to, and found within all the pezizomycotina subphyla of the ascomycota, for which data are available, but not the saccharomycotina or taphrinomycotina subphyla. intron analysis indicated that both intron loss and gain have occurred in this gene. the orthologous proteins demonstrate considerable size variation (between 663 and 897 amino acids); with almo ...200818678248
farnesol induces the transcriptional accumulation of the aspergillus nidulans apoptosis-inducing factor (aif)-like mitochondrial oxidoreductase.farnesol (foh) is a non-sterol isoprenoid produced by dephosphorylation of farnesyl pyrophosphate, a catabolite of the cholesterol biosynthetic pathway. these isoprenoids inhibit proliferation and induce apoptosis. it has been shown previously that foh triggers morphological features characteristic of apoptosis in the filamentous fungus aspergillus nidulans. here, we investigate which pathways are influenced through foh by examining the transcriptional profile of a. nidulans exposed to this isop ...200818681941
regulation of apical dominance in aspergillus nidulans hyphae by reactive oxygen fungal hyphae, apical dominance refers to the suppression of secondary polarity axes in the general vicinity of a growing hyphal tip. the mechanisms underlying apical dominance remain largely undefined, although calcium signaling may play a role. here, we describe the localized accumulation of reactive oxygen species (ros) in the apical region of aspergillus nidulans hyphae. our analysis of atma (atm) and prpa (parp) mutants reveals a correlation between localized production of ros and enforc ...200818689883
comparative in vitro activities of posaconazole, voriconazole, itraconazole, and amphotericin b against aspergillus and rhizopus, and synergy testing for rhizopus.we compared the in vitro activities of posaconazole, voriconazole, itraconazole, and amphotericin b against clinical isolates of aspergillus spp. and rhizopus spp., and explored the in vitro interaction between posaconazole and amphotericin b against rhizopus spp. clinical strains of 82 aspergillus spp. (43 aspergillus fumigatus, 29 a. flavus, 7 a. niger, 2 a. terreus, 1 a. nidulans) and 11 rhizopus oryzae isolates were tested in accordance with clsi m38-a microdilution guidelines. in vitro acti ...200819180726
construction of a citrinin gene cluster expression system in heterologous aspergillus oryzae.filamentous fungi are considered an attractive resource for the discovery and production of bioactive compounds. to facilitate molecular breeding, biosynthetic genes must be rapidly identified. but, even after the chemical structure of a compound is identified, finding the corresponding biosynthetic genes in the fungal genome still remains a challenge. in an attempt to overcome this difficulty and to easily characterize each gene in a cluster, we constructed a heterologous expression system usin ...200819111642
arfb links protein lipidation and endocytosis to polarized growth of aspergillus nidulans.aspergillus nidulans undergoes polarized hyphal growth during the majority of its life cycle. regulatory mechanisms for hyphal polarity have been intensively investigated in a variety of filamentous fungi. two important cellular processes, which have received recent attention, include protein myristoylation and endocytosis. it is clear that protein myristoylation is essential for polarity establishment because germinating a. nidulans conidia lost polarity in the presence of cerulenin, a lipid me ...200819704790
[in vitro activity of anidulafungin. comparison with the activity of other echinocandins].anidulafungin is a new echinocandin that acts by inhibiting (1,3)-beta-d-glucan synthesis in the fungal cell wall. this agent is a semisynthetic lipopeptide synthesized from a fermentation product of aspergillus nidulans. the spectrum of activity of anidulafungin includes candida and aspergillus, the two main etiological agents causing invasive fungal infections. this drug is also active against strains of these genera resistant to azoles or amphotericin b. however, anidulafungin is not active a ...200819572429
comparative evolutionary histories of the fungal chitinase gene family reveal non-random size expansions and contractions due to adaptive natural selection.gene duplication and loss play an important role in the evolution of novel functions and for shaping an organism's gene content. recently, it was suggested that stress-related genes frequently are exposed to duplications and losses, while growth-related genes show selection against change in copy number. the fungal chitinase gene family constitutes an interesting case study of gene duplication and loss, as their biological roles include growth and development as well as more stress-responsive fu ...200819204807
roles of the aspergillus nidulans homologues of tup1 and ssn6 in chromatin structure and cell viability.for three different carbon catabolite repressible promoters, alca, alcr and the bidirectional promoter prnd-prnb, a deletion of rcoa, the aspergillus nidulans homologue of tup1, does not result in carbon catabolite derepression. surprisingly, it results in disruption of the chromatin default structure of alcr and prnd-prnb promoters. in these promoters, and at variance with the wild type, repression occurs in the absence of nucleosome positioning. for alcr, repression occurs together with a nucl ...200819054105
the fate of gene duplicates in the genomes of fungal pathogens.understanding how molecular changes underlie phenotypic variation within and between species is one of the main goals of evolutionary biology and comparative genetics. the recent proliferation of sequenced fungal genomes offers a unique opportunity to start elucidating the extreme phenotypic diversity in the kingdom fungi.1-4 we attempted to investigate the contribution of gene families to the evolutionary forces shaping the diversity of pathogenic lifestyles among the fungi.5 we studied a famil ...200819513258
effect of some food preservatives on the lipolytic activity of beef luncheon fungi.beef luncheon meat is one of the most popular meals in several countries in the world including egypt. thirty one fungal species and 3 species varieties were recovered from 30 samples of beef luncheon meat collected from different supermarkets in qena. alternaria, aspergillus, emericella, mucor, mycosphaerella, penicillium and rhizopus were the most common genera on the two types of media. from the above genera, the most prevalent species were alternaria alternate, aspergillus flavus, a. fumigat ...200823997619
ecological and physiological studies on soil fungi at western region, libya.sixty three species and 5 varieties belonging to 30 fungal genera were collected from 75 soil samples. cultivated (29 genera and 58 species + 5 var.), desert (22 and 35 + 2 var.) and saline soil (21 and 41 + 1 var.) fungi were recovered on glucose-, cellulose- and 50% sucrose-czapek's agar at 28℃. the most common genera were alternaria, aspergillus, emericella, fusarium, mycosphaerella, nectria and penicillium. the most prevalent species from the three types of soils on the three types of media ...200823997599
mechanism to combat cobalt toxicity in cobalt resistant mutants of aspergillus nidulans.characteristics of fungal species tolerant to high levels of metals in natural environment can be amplified by isolation and selection of resistant mutants. step-by-step culturing led to identification of highly stable co-resistant (co(r)) mutants of a. nidulans. based on two distinct morphological features, co-resistant mutants were categorized as co(r)i and co(r)ii. the two mutants varied in their growth behavior and colony morphology that were reflected in supplemented as well as unsupplement ...200723100687
development and characterization of nickel accumulating mutants of aspergillus nidulans.stable mutants of aspergillus nidulans, resistant to 1 mm ni were developed by step-by-step repeated culturing of the fungus on the medium containing increasing concentrations of nickel chloride. characterization of mutants could differentiate them into two categories ni(r) i and ni(r) ii. each category of mutants exhibited alterations in growth, conidial germination and melanin secretion both in ni-free and ni-containing media. ni(r) ii mutants were little slow in growth with sparse mycelia and ...200723100672
biodiversity of epilithic cyanobacteria from freshwater streams of kakoijana reserve forest, assam, india.the biodiversity of epilithic cyanobacteria from one of the unexplored habitats of freshwater streams of kakoijana reserve forest of assam, india was estimated. this paper lists a total of 29 species representing 18 genera of 12 families and 4 orders as per recent system of classification. morphological descriptions, common habitats and distribution pattern were described for each species identified that were represented systematically. of these 29 species, 11 were unicellular, 9 non-heterocytou ...200723100670
an activating mutation of the sclerotinia sclerotiorum pac1 gene increases oxalic acid production at low ph but decreases virulence.summary the production of oxalic acid by sclerotinia sclerotiorum is regulated by the ambient ph environment. this regulation and that of a few investigated ph-responsive genes is mediated in part by the zinc finger transcription factor encoded by pac1, an orthologue of the aspergillus nidulans pacc gene. we manipulated the pac1 sequence by site-directed mutagenesis to create a dominant activating pac1(c) mutation and introduced this allele into a pac1 loss-of-function (deltapac1) strain. consis ...200720507525
antimicrobial, wound healing and antioxidant activities of anthocephalus cadamba.anthocephalus cadamba (roxb.) miq. syn a. chinensis (lamk) a. rich (rubiaceae) is ethnomedicinally widely used in the form of paste by tribe in western ghats for treating skin diseases. in this context, antimicrobial potential of a. cadamba against a wide range of microorganisms was studied. to validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing. the alchoholic and aqueou ...200720161916
oxylipins as developmental and host-fungal communication signals.pathogenic microbes and their hosts have acquired complex signalling mechanisms to appraise themselves of the environmental milieu in the ongoing battle for survival. several recent studies have implicated oxylipins as a novel class of host-microbe signalling molecules. oxylipins represent a vast and diverse family of secondary metabolites that originate from the oxidation or further conversion of polyunsaturated fatty acids. among the microbial oxylipins, the fungal oxylipins are best character ...200717276068
phosphopantetheinyl transferase cfwa/npga is required for aspergillus nidulans secondary metabolism and asexual development.polyketide synthases (pkss) and/or nonribosomal peptide synthetases (nrpss) are central components of secondary metabolism in bacteria, plants, and fungi. in filamentous fungi, diverse pkss and nrpss participate in the biosynthesis of secondary metabolites such as pigments, antibiotics, siderophores, and mycotoxins. however, many secondary metabolites as well as the enzymes involved in their production are yet to be discovered. both pkss and nrpss require activation by enzyme members of the 4'-p ...200717277172
accurate prediction of the aspergillus nidulans terrequinone gene cluster boundaries using the transcriptional regulator laea.laea is a regulatory protein of the genus aspergillus which controls global expression of secondary metabolism gene clusters. during a previous genome-wide transcriptional profiling screen, numerous novel gene clusters were found to be regulated by laea including a cluster required for the production of the antitumor agent terrequinone a. beginnings and ends of secondary metabolite gene clusters are difficult to predict by gene sequence alone, but sharp demarcation of transcriptional control by ...200717291795
genotoxicity (mitotic recombination) of the cancer chemotherapeutic agents cisplatin and cytosine arabinoside in aspergillus nidulans.cisplatin (cis-diamminedichloroplatinum, cis-ddp) and cytosine arabinoside (ara-c) are anticancer drugs used in the treatment of human cancer. the two chemotherapeutic drugs were tested in current research for their recombinogenic potential in diploid cells of aspergillus nidulans. non-cytotoxic concentrations of ara-c (0.4 and 0.8 microm) and cis-ddp (1.5, 3.0 and 6.0 microm) were strong recombinagens in a. nidulans ut448//a757 diploid strain, which induced homozygosis of recessive genetic mark ...200717306432
small molecule inhibitors of histone arginine methyltransferases: homology modeling, molecular docking, binding mode analysis, and biological evaluations.the screening of the inhibition capabilities of dye-like small molecules from a focused library against both human prmt1 and aspergillus nidulans rmta is reported as well as molecular modeling studies (homology modeling, molecular docking, and 3-d qsar) of the catalytic domain of the prmt1 fungal homologue rmta. the good correlation between computational and biological results makes rmta a reliable tool for screening arginine methyltransferase inhibitors. in addition, the binding mode analyses o ...200717323938
the evolutionary history of cytochrome p450 genes in four filamentous ascomycetes.the cytochrome p450 system is important in fungal evolution for adapting to novel ecological niches. to elucidate the evolutionary process of cytochrome p450 genes in fungi with different life styles, we studied the patterns of gene gains and losses in the genomes of four filamentous ascomycetes, including two saprotrophs (aspergillus nidulans (an) and neurospora crassa (nc)) and two plant pathogens (fusarium graminearum (fg) and magnaporthe grisea (mg)).200717324274
transcriptional control of gluconeogenesis in aspergillus nidulans.aspergillus nidulans can utilize carbon sources that result in the production of tca cycle intermediates, thereby requiring gluconeogenesis. we have cloned the acug gene encoding fructose-1,6 bisphosphatase and found that expression of this gene is regulated by carbon catabolite repression as well as by induction by a tca cycle intermediate similar to the induction of the previously studied acuf gene encoding phosphoenolpyruvate carboxykinase. the acun356 mutation results in loss of growth on gl ...200717339216
characterization of the nika histidine kinase implicated in the phosphorelay signal transduction of aspergillus nidulans, with special reference to fungicide responses.we recently compiled a complete list of phosphorelay signal transduction components in the model filamentous fungus aspergillus nidulans. in this study, we characterized a histidine protein kinase (designated nika) that is found in many fungi, with special reference to responses to potent fungicides (iprodione and fludioxonil). we provided evidence that not only nika, but also two downstream response regulators (sska and srra) are crucially implicated in the mode of action of these fungicides, a ...200717341812
genomics of aspergillus oryzae.the genome sequence of aspergillus oryzae, a fungus used in the production of the traditional japanese fermentation foods sake (rice wine), shoyu (soy sauce), and miso (soybean paste), has revealed prominent features in its gene composition as compared to those of saccharomyces cerevisiae and neurospora crassa. the a. oryzae genome is extremely enriched with genes involved in biomass degradation, primary and secondary metabolism, transcriptional regulation, and cell signaling. even compared to t ...200717341818
the proline permease of aspergillus nidulans: functional replacement of the native cysteine residues and properties of a cysteine-less transporter.the major proline transporter (prnb) of aspergillus nidulans belongs to the amino acid polyamine organocation (apc) transporter superfamily. members of this family have not been subjected to systematic structure-function relationship studies. in this report, we examine the functional replacement of the three native cys residues (cys54, cys352 and cys530) of prnb and the properties of an engineered cys-less prnb protein, as background for employing a cys-scanning mutagenesis approach. we show tha ...200717350864
the tightly regulated promoter of the xana gene of aspergillus nidulans is included in a aspergillus nidulans the xana gene codes for a xanthine alpha-ketoglutarate-dependent dioxygenase, an enzyme only present in the fungal kingdom. the 5' region of this gene, including its putative promoter and the first 54 codons of the open reading frame, together with the first intron is duplicated in the genome. this duplication corresponds to a helitron, a eukaryotic element proposed to transpose replicatively by the rolling circle mechanism. we show that the regulation of xana conforms to ...200717367381
genomics-driven discovery of pks-nrps hybrid metabolites from aspergillus the postgenomic era it has become increasingly apparent that the vast number of predicted biosynthesis genes of microorganisms is not reflected by the metabolic profile observed under standard fermentation conditions. in the absence of a particular (in most cases unknown) trigger these gene loci remain silent. because these cryptic gene clusters may code for the biosynthesis of important virulence factors, toxins, or even drug candidates, new strategies for their activation are urgently neede ...200717369821
the light-dependent regulator velvet a of aspergillus nidulans acts as a repressor of the penicillin biosynthesis.the biosynthesis of the beta-lactam antibiotic penicillin in aspergillus nidulans is catalysed by three enzymes that are encoded by the genes acva, ipna and aata. several studies have indicated that these genes are controlled by a complex regulatory network, including a variety of cis-acting dna elements and regulatory factors. until now, however, relatively little information is available on external signals and their transmission influencing the expression of the structural genes. here, we sho ...200717375284
a regulator of a g protein signalling (rgs) gene, cag8, from the insect-pathogenic fungus metarhizium anisopliae is involved in conidiation, virulence and hydrophobin synthesis.regulators of the g protein signalling (rgs) pathway have been implicated in the control of a diverse array of cellular functions, including conidiation in filamentous fungi. however, the regulatory processes involved in conidiation in insect-pathogenic fungi are poorly understood. since conidia are the infective propagules in these fungi, an understanding of the regulatory processes involved in conidiation is essential to the development of an effective biocontrol fungus. here, the cloning and ...200717379711
interactions of isopenicillin n synthase with cyclopropyl-containing substrate analogues reveal new mechanistic insight.isopenicillin n synthase (ipns), a non-heme iron oxidase central to penicillin and cephalosporin biosynthesis, catalyzes an energetically demanding chemical transformation to produce isopenicillin n from the tripeptide delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-valine (acv). we describe the synthesis of two cyclopropyl-containing tripeptide analogues, delta-(l-alpha-aminoadipoyl)-l-cysteinyl-beta-methyl-d-cyclopropylglycine and delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-cyclopropylglycine, desig ...200717397141
a homologue of the aspergillus velvet gene regulates both cephalosporin c biosynthesis and hyphal fragmentation in acremonium chrysogenum.the aspergillus nidulans velvet (vea) gene encodes a global regulator of gene expression controlling sexual development as well as secondary metabolism. we have identified the vea homologue acvea from acremonium chrysogenum, the major producer of the beta-lactam antibiotic cephalosporin c. two different disruption strains as well as the corresponding complements were generated as a prelude to detailed functional analysis. northern hybridization and quantitative real-time pcr clearly indicate tha ...200717400783
a type b feruloyl esterase from aspergillus nidulans with broad ph applicability.a hypothetical protein an1772.2 of aspergillus nidulans was found to have a 56% identity with a known type c ferulic acid esterase (fae) from talaromyces stipitatus. in addition, it contained a 13-amino acid conserved region flanking the characteristic g-x-s-x-g motif of a serine esterase, suggesting a fae function for the protein. the putative fae was successfully cloned from the genomic dna and expressed in saccharomyces cerevisiae. the recombinant protein exhibited high fae activities. theref ...200717043824
nuclear export of the transcription factor nira is a regulatory checkpoint for nitrate induction in aspergillus nidulans.nira, the specific transcription factor of the nitrate assimilation pathway of aspergillus nidulans, accumulates in the nucleus upon induction by nitrate. nira interacts with the nuclear export factor kapk, which bridges an interaction with a protein of the nucleoporin-like family (npla). nitrate induction disrupts the nira-kapk interaction in vivo, whereas kapk associates with nira when this protein is exported from the nucleus. a kpak leptomycin-sensitive mutation leads to inducer-independent ...200717116695
the protein kinase c orthologue pkca plays a role in cell wall integrity and polarized growth in aspergillus nidulans.the calc2 mutation in aspergillus nidulans causes hypersensitivity to calcofluor white, along with other drug sensitivities that indicate a defect in cell wall integrity. we have cloned calc by complementation, isolating the a. nidulans orthologue of protein kinase c (pkca). the pkca allele of the calc2 strain contains a mutation predicted to introduce a charged arginine residue in place of neutral glycine at a conserved site located immediately beside the c1b regulatory domain. both pkca and ca ...200717118679
a chitinase gene, chib, involved in the autolytic process of aspergillus nidulans.chitinases are thought to be involved in the morphogenesis and autolysis of filamentous fungi. we cloned a gene (chib) encoding a class v chitinase from aspergillus nidulans. chib expressed in escherichia coli had chitin-hydrolyzing activity, indicating that chib encoded a chitinase. deletion of chib affected neither germination efficiency nor hyphal growth rate, but considerably reduced the intracellular and extracellular chitinase activities. the decrease in hyphal dry weight during autolytic ...200717119968
differential physiological and developmental expression of the uapa and azga purine transporters in aspergillus this article we study the cellular expression of uapa and azga, the two major purine transporters of aspergillus nidulans, by constructing strains expressing, from their native promoters, fully functional fluorescent (uapa-sgfp, azga-sgfp) or immunological (uapa-his) chimeric transporters. epifluorescence microscopy and immunodetection showed that under different physiological conditions and during aspergillus development: (i) uapa and azga expression in the plasma membrane becomes evident ea ...200717126042
aspergillus nidulans vea subcellular localization is dependent on the importin alpha carrier and on light.the vea gene is a light-dependent regulator governing development and secondary metabolism in aspergillus nidulans. we have identified a putative bipartite nuclear localization signal (nls) motif in the a. nidulans vea amino acid sequence and demonstrated its functionality when expressed in yeast. furthermore, migration of vea to the nucleus was dependent on the importin alpha. this bipartite nls is also functional when vea is expressed in a. nidulans. interestingly, we found that vea migration ...200717163983
an allosteric-feedback mechanism for protein-assisted group i intron splicing.the i-anii maturase facilitates self-splicing of a mitochondrial group i intron in aspergillus nidulans. binding occurs in at least two steps: first, a specific but labile encounter complex rapidly forms and then this intermediate is slowly resolved into a native, catalytically active rna/protein complex. here we probe the structure of the rna throughout the assembly pathway. although inherently unstable, the intron core, when bound by i-anii, undergoes rapid folding to a near-native state in th ...200717164477
optimization of heterologous production of the polyketide 6-msa in saccharomyces cerevisiae.polyketides are a group of natural products that have gained much interest due to their use as antibiotics, cholesterol lowering agents, immunosuppressors, and as other drugs. many organisms that naturally produce polyketides are difficult to cultivate and only produce these metabolites in small amounts. it is therefore of general interest to transfer polyketide synthase (pks) genes from their natural sources into heterologous hosts that can over-produce the corresponding polyketides. in this st ...200717171715
the first filamentous fungal genome sequences: aspergillus leads the way for essential everyday resources or dusty museum specimens?the published aspergillus genome sequences (a. nidulans, a. fumigatus, a. oryzae) and further sequence data from a. clavatus, neosartorya fischeri, a. flavus, a. niger, a. parasiticus and a. terreus are the first from a group of related filamentous fungi. they indicate the gains possible from genomic approaches, but also problems that arise after the sequences are finished. benefits include a greater understanding of genome structure and evolution, insights into gene regulation, predictions of n ...200717185529
susceptibility of environmental versus clinical strains of pathogenic aspergillus.the objective of this study was to compare the antifungal susceptibility profiles of 307 environmental strains and 139 clinical isolates of aspergillus belonging to six different species. clinical and environmental strains with minimal inhibitory concentrations (mics) or minimal effective concentrations >or=4microg/ml to amphotericin b (amb), itraconazole (itc), voriconazole and caspofungin were seldom detected. however, the susceptibility profile of environmental aspergillus non-fumigatus strai ...200717189101
novel phacb-encoded cytochrome p450 monooxygenase from aspergillus nidulans with 3-hydroxyphenylacetate 6-hydroxylase and 3,4-dihydroxyphenylacetate 6-hydroxylase activities.aspergillus nidulans catabolizes phenylacetate (phac) and 3-hydroxy-, 4-hydroxy-, and 3,4-dihydroxyphenylacetate (3-oh-phac, 4-oh-phac, and 3,4-dioh-phac, respectively) through the 2,5-dihydroxyphenylacetate (homogentisic acid) catabolic pathway. using cdna subtraction techniques, we isolated a gene, denoted phacb, which is strongly induced by phac (and its hydroxyderivatives) and encodes a new cytochrome p450 (cyp450). a disrupted phacb strain (delta phacb) does not grow on 3-hydroxy-, 4-hydrox ...200717189487
highly efficient concerted evolution in the ribosomal dna repeats: total rdna repeat variation revealed by whole-genome shotgun sequence data.repeat families within genomes are often maintained with similar sequences. traditionally, this has been explained by concerted evolution, where repeats in an array evolve "in concert" with the same sequence via continual turnover of repeats by recombination. another form of evolution, birth-and-death evolution, can also explain this pattern, although in this case selection is the critical force maintaining the repeats. the level of intragenomic variation is the key difference between these two ...200717200233
sulfate transport in aspergillus nidulans: a novel gene encoding alternative sulfate aspergillus nidulans sulfate is taken up by sulfate permease encoded by the sb gene. a unique tight auxotrophic mutant with an impaired promoter region of the sulfate permease gene, sb1(pr), was isolated. three suppressor genes were cloned by complementation of this mutation. one of them, described here, is the asta gene (alternative sulfate transporter) derived from a genomic library of the japanese a. nidulans iam 2006 strain. in the reference strain of glasgow origin the asta gene was foun ...200717223367
characterization of regulatory non-catalytic hexokinases in aspergillus nidulans.hexokinases catalyse the first step in glucose metabolism and play a role in glucose sensing in mammals, plants and fungi. we describe a new class of hexokinases that appear to be solely regulatory in function. the aspergillus nidulans hxkd gene (formerly named xprf) encodes a hexokinase-like protein. we constructed hxkddelta gene disruption mutants which showed increased levels of extracellular protease in response to carbon starvation. the hxkddelta mutations are not completely recessive, indi ...200717226029
aspergillus nidulans dis1/xmap215 protein alpa localizes to spindle pole bodies and microtubule plus ends and contributes to growth directionality.the dynamics of cytoplasmic microtubules (mts) is largely controlled by a protein complex at the mt plus end. in schizosaccharomyces pombe and in filamentous fungi, mt plus end-associated proteins also determine growth directionality. we have characterized the dis1/xmap215 family protein alpa from aspergillus nidulans and show that it determines mt dynamics as well as hyphal morphology. green fluorescent protein-tagged alpa localized to mt-organizing centers (centrosomes) and to mt plus ends. th ...200717237365
point mutations in the stem region and the fourth aaa domain of cytoplasmic dynein heavy chain partially suppress the phenotype of nudf/lis1 loss in aspergillus nidulans.cytoplasmic dynein performs multiple cellular tasks but its regulation remains unclear. the dynein heavy chain has a n-terminal stem that binds to other subunits and a c-terminal motor unit that contains six aaa (atpase associated with cellular activities) domains and a microtubule-binding site located between aaa4 and aaa5. in aspergillus nidulans, nudf (a lis1 homolog) functions in the dynein pathway, and two nudf6 partial suppressors were mapped to the nuda dynein heavy chain locus. here we i ...200717237507
a novel interaction between n-myristoylation and the 26s proteasome during cell morphogenesis.n-myristoylation is a protein lipidation event in which myristate is covalently linked to the n-terminal glycine of target proteins. in aspergillus nidulans, the n-myristoylation deficient swof1 mutant was previously shown to lose cell polarity during the early morphogenic event of germ tube emergence. to further investigate this defect, we mutagenized swof1 and recovered six partial suppressors designated ssf (suppressor of swof1). the secondary mutations enabled swof1 to partially bypass its g ...200717238925
development of novel real-time pcr assays for detection and differentiation of eleven medically important aspergillus and candida species in clinical the present study, novel real-time pcr assays targeting the fungal its2 region were developed for the detection and differentiation of medically important aspergillus species (aspergillus fumigatus, aspergillus flavus, aspergillus nidulans, aspergillus niger, and aspergillus terreus) and candida species (candida albicans, candida dubliniensis, candida glabrata, candida krusei, candida parapsilosis, and candida tropicalis) using a lightcycler instrument. the combination of a group-specific and ...200717251398
two aspergillus nidulans genes encoding methylenetetrahydrofolate reductases are up-regulated by homocysteine.methylenetetrahydrofolate reductase (mthfr) catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a co-substrate in the synthesis of methionine from homocysteine. we have cloned and characterized two aspergillus nidulans genes encoding mthfrs: meta and metf. mutations in either gene result in methionine requirement; the meta-encoded enzyme is responsible for only 10-15% of total mthfr activity. these two enzymes belong to different classes of mthfrs. mutations in ...200717257865
proteome map of aspergillus nidulans during osmoadaptation.the model filamentous fungus aspergillus nidulans, when grown in a moderate level of osmolyte (+0.6m kcl), was previously found to have a significantly reduced cell wall elasticity (biotech prog, 21:292, 2005). in this study, comparative proteomic analysis via two-dimensional gel electrophoresis (2de) and matrix-assisted laser desorption ionization/time-of-flight (maldi-tof) mass spectrometry was used to assess molecular level events associated with this phenomenon. thirty of 90 differentially e ...200717258477
synthesis, characterization and biological activity of complexes of 2-hydroxy-3,5-dimethylacetophenoneoxime (hdmaox) with copper(ii), cobalt(ii), nickel(ii) and palladium(ii).a new series of complexes of 2-hydroxy-3,5-dimethyl acetophenone oxime (hdmaox) with cu(ii), co(ii), ni(ii) and pd(ii) have been prepared and characterized by different physical techniques. infrared spectra of the complexes indicate deprotonation and coordination of the phenolic oh. it also confirms that nitrogen atom of the oximino group contributes to the complexation. electronic spectra and magnetic susceptibility measurements reveal square planar geometry for cu(ii), ni(ii) and pd(ii) comple ...200717258502
l-arginine influences the structure and function of arginase mrna in aspergillus nidulans.expression of the arginase structural gene (agaa) in aspergillus nidulans is subject to complex transcriptional and post-transcriptional regulation. arginase mrna has a long 5'-utr sequence. analysis of this sequence in silico revealed its putative complex secondary structure, the presence of arginine-binding motifs (arginine aptamers) and a short intron with two potential 3' splicing sites. in this report we present evidence that l-arginine (i) binds directly to the arginase 5'-utr; (ii) invoke ...200717261076
the aspergillus nidulans pkca gene is involved in polarized growth, morphogenesis and maintenance of cell wall integrity.the protein kinase c (pkc) family participates in maintaining integrity and growth of fungal cell walls. however, the precise molecular role of these proteins in the filamentous fungi remains unknown. in this work, pkca, the gene encoding the pkc homolog in the filamentous fungus aspergillus nidulans, was cloned and its function analyzed using a conditional alca-pkc mutant strain. repression of pkca expression resulted in increased conidial swelling, decreased rates of hyphal growth, changes in ...200717406869
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
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
suppression of the acuh13 and acuh31 nonsense mutations in the carnitine/acylcarnitine translocase (acuh) gene of aspergillus nidulans by the g265s substitution in the domain 2 of the release factor erf1.a search for suppressors of the carnitine/acylcarnitine translocase (cact) deficiency in aspergillus nidulans permitted the identification of the suae7 mutation, mapping at a new translational suppressor (suae) gene. the suae gene is essential in a. nidulans and encodes the eukaryotic release factor 1 (erf1). the suae7 mutation suppresses two acuh alleles (acuh13 and acuh31), both carrying nonsense mutations in the cact encoding gene that involve the replacement of a cag (gln) codon with a prema ...200716971148
role of microtubules in tip growth of fungi.polarized cell growth is observed ubiquitously in all living organisms. tip growth of filamentous fungi serves as a typical model for polar growth. it is well known that the actin cytoskeleton plays a central role in cellular growth. in contrast, the role of microtubules in polar growth of fungal tip cells has not been critically addressed. our recent study, using a green fluorescent protein (gfp)-labeled tubulin-expressing strain of the filamentous fungus aspergillus nidulans and treatment with ...200717021934
[ltr retrotransposons from genomes of aspergillus fumigatus and a. nidulans].fungi aspergillus spp. are able to infect all tissues and organs and often cause invasive mycosis (aspergillosis), which is usually a fatal disease, especially in the patients with compromised immune system. microbiological monitoring of these infectious agents is necessary in modem medical facilities. mobile elements can be used as markers for identification of species and strains of aspergillus found indoors as well as in aspergillosis diagnostics. genomic sequences of two representative asper ...200718240565
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
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
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
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
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