| penicillin biosynthesis. | | 1994 | 7765141 |
| carbon metabolism. | | 1994 | 7765142 |
| vectors for genetic manipulation. | | 1994 | 7765143 |
| homologous recombination. | | 1994 | 7765145 |
| translational suppression. | | 1994 | 7765146 |
| linkage map and locus list. | | 1994 | 7765147 |
| gene symbols. | | 1994 | 7765148 |
| media. | | 1994 | 7765149 |
| sources of strains, vectors, libraries. | | 1994 | 7765150 |
| development of a new transformant selection system for penicillium chrysogenum: isolation and characterization of the p. chrysogenum acetyl-coenzyme a synthetase gene (faca) and its use as a homologous selection marker. | a new transformation system for the filamentous fungus penicillium chrysogenum is described, based on the use of the homologous acetyl-coenzyme a synthetase (faca) gene as a selection marker. acetate-non-utilizing (fac-) strains of p. chrysogenum were obtained by positive selection for spontaneous resistance to fluoroacetate. among these fac mutants putative faca strains were selected for a loss of acetyl-coenzyme a (coa) synthetase activity. the faca gene, coding for the enzyme acetyl-coa synth ... | 1993 | 7765289 |
| isolation and characterization of two chitin synthase genes from aspergillus nidulans. | two chitin synthase genes, designated chsa and chsb, were isolated from aspergillus nidulans with the saccharomyces cerevisiae chs2 gene as the hybridization probe. nucleotide sequencing showed that chsa and chsb encoded polypeptides consisting of 1013 and 916 amino acid residues, respectively; the hydropathy profiles of the enzymes were similar to those of other fungal chitin synthases. northern analysis indicated that both genes were transcribed, suggesting that cellular chitin in a. nidulans ... | 1994 | 7765508 |
| genetic modification of an echinocandin b-producing strain of aspergillus nidulans to produce mutants blocked in sterigmatocystin biosynthesis. | the production of echinocandin b (ecb), a lipopolypeptide used for chemical manufacture of the anti-candida agent cilofungin, was accomplished by fermentation using a strain of aspergillus nidulans. in addition to ecb, this fermentation also produces a significant amount of sterigmatocystin (st), a potent carcinogen structurally related to the aflatoxins. mutants blocked in the st biosynthetic pathway were created by genetic modification of the polyploid production strain c747. the following ste ... | 1994 | 7765669 |
| isolation of a chitin synthase gene (chsc) of aspergillus nidulans. | we isolated a class i chitin synthase gene (chsc) from aspergillus nidulans. expression of this gene was confirmed by northern analysis and by sequencing of the pcr-amplified dna fragments from cdna. chsc disruptants showed no difference of morphology in the asexual cycle and no difference of growth rate compared to a wild-type strain. | 1994 | 7765719 |
| antifungal effects of allium sativum (garlic) extract against the aspergillus species involved in otomycosis. | otomycosis due to saprophytic keratolytic fungi represents a small percentage of clinical external otitis. although there are certain antibacterial and antifungal agents available, they usually are very caustic, potentially ototoxic and cannot be used if the ear drum is perforated. garlic is utilized as a folk medicine in many countries for its antimicrobial and other beneficial properties. in response to a lack of otic preparations, the authors studied the efficacy of garlic extracts against th ... | 1995 | 7765862 |
| purification of a heat-stable chitin deacetylase from aspergillus nidulans and its role in cell wall degradation. | an extracellular chitin deacetylase activity has been purified to homogeneity from autolyzed cultures of aspergillus nidulans. this enzyme is an acidic glycoprotein with a pi of 2.75 and a 28% (wt/wt) carbohydrate content. the apparent m(r) of the enzyme estimated by sds/page and superose 12 (f.p.l.c.) was around 27,000. the enzyme had an optimum ph at 7.0 and was stable in the ph range 4.0-7.5. its optimum temperature of reaction was 50 degrees c, and it was stable from 30 degrees to 100 degree ... | 1995 | 7765883 |
| extragenic suppressors of a dynein mutation that blocks nuclear migration in aspergillus nidulans. | cytoplasmic dynein is a large molecular weight protein complex that functions as a microtubule-dependent, negative, end-directed "motor." mutations in nuda, which encodes the heavy chain of cytoplasmic dynein, inhibit nuclear migration in aspergillus nidulans. this paper describes the selection and characterization of extragenic suppressors of the nuda1 mutation preparatory to the identification of other proteins that interact directly or indirectly with the cytoplasmic dynein heavy chain. to fa ... | 1995 | 7768435 |
| polarity of meiotic gene conversion is 5' to 3' within the niad gene of aspergillus nidulans. | we have examined polarity of meiotic gene conversion in the niia-niad gene cluster of aspergillus nidulans in two-point crosses. the type and position of the mutations represented by the niad alleles and the correlation between the relative frequency of gene conversion and the physical position of these mutations were determined. we show that polarity of meiotic gene conversion is 5' to 3' (transcribed strand) within the niad gene. additional crosses involving a niia allele and a niad allele sho ... | 1995 | 7770039 |
| isolation and characterisation of genes for sulphate activation and reduction in aspergillus nidulans: implications for evolution of an allosteric control region by gene duplication. | a region of the aspergillus nidulans genome carrying the sa and sc genes, encoding paps reductase and atp sulphurylase, respectively, was isolated by transformation of an sa mutant with a cosmid library. the genes were subcloned and their functions confirmed by retransformation and complementation of a. nidulans strains carrying sa and sc mutations. the physical distance of 2 kb between the genes corresponds to a genetic distance of 1 cm. while the deduced amino acid sequence of the sa gene prod ... | 1995 | 7770049 |
| genes for beta-lactam antibiotic biosynthesis. | the genes pcbab, pcbc and pende encoding enzymes involved in the biosynthesis of penicillin have been cloned from penicillium chrysogenum and aspergillus nidulans. they are clustered in chromosome i (10.4 mb) of p. chrysogenum, but they are located in chromosome ii of penicillium notatum (9.6 mb) and in chromosome vi (3.0 mb) of a. nidulans. expression studies have shown that each gene is expressed as a single transcript from separate promoters. enzyme regulation studies and gene expression anal ... | 1995 | 7771766 |
| characterization of a prolactin-inducible gene, clone 15, in t cells. | to examine how prl regulates lymphocyte proliferation, a number of prl-activated genes were identified from a prl-dependent rat t lymphoma cell line, nb2. one of the downstream genes in the prl signaling cascade was identified as clone 15 (c15). prl stimulation of quiescent nb2 t cells results in the expression of a 1.7-kilobase c15 mrna, which reaches maximum levels between 8 and 10 h after stimulation. corresponding [3h]thymidine incorporation experiments show that the maximum level of c15 mrn ... | 1995 | 7776977 |
| a case of chronic necrotizing pulmonary aspergillosis due to aspergillus nidulans. | a 55-year old man without immunosuppression clinically showed a coin lesion in the right lower lung on the chest radiographs. aspergillus nidulans was isolated and identified in both trans-bronchial lung biopsy specimen and resected tissue. the specimens revealed characteristics of chronic necrotizing pulmonary aspergillosis pathologically. very few reports on cases of pulmonary aspergillosis due to a. nidulans exist, and we were not able to find any reports of similar cases. this case may be th ... | 1994 | 7777037 |
| the genetics of nuclear migration in fungi. | | 1995 | 7779511 |
| a heuristic approach to the analysis of enzymic catalysis: reaction of delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-alpha-aminobutyrate and delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-allylglycine catalyzed by isopenicillin n synthase isozymes. | isopenicillin n synthase (ipns) catalyzes the oxidative cyclization of delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-valine to isopenicillin n. it is proposed that the multiple products produced from certain substrate analogues result from pathway branching after formation of a ferryl oxene intermediate. we have been interested in ascertaining the reasons for multiple product formation. one possibility is that the products are predisposed toward formation once the beta-lactam ring and the ferryl ox ... | 1995 | 7779800 |
| sequence analysis of the aspergillus nidulans pectate lyase pela gene and evidence for binding of promoter regions to crea, a regulator of carbon catabolite repression. | the nucleic acid and deduced amino-acid sequences of the pectate lyase gene (pela) from aspergillus nidulans are presented. the pela gene contains two short introns, 68 and 49 bp in length, and encodes a peptide of 326 amino acids. five transcriptional start sites are clustered between 65 and 79 bp upstream of the start codon as determined by primer extension. comparison of the amino-acid sequences of pectate or pectin lyases from bacteria, fungi and plants revealed less than 30% overall identit ... | 1995 | 7788717 |
| molecular cloning and analysis of nre, the major nitrogen regulatory gene of penicillium chrysogenum. | we have isolated the penicillium chrysogenum nre gene which is homologous to the major nitrogen regulatory genes area from aspergillus nidulans and nit-2 from neurospora crassa. overall, nre shows 60% identity to area and 30% identity to nit-2 at the amino-acid level. the gene encodes a protein of 835 amino-acid residues and contains a single cys2/cys2-type zinc finger with an adjacent basic region and a putative acidic activation region. in the dna-binding domain, 98% of the amino-acid residues ... | 1995 | 7788718 |
| a mini-promoter lacz gene fusion for the analysis of fungal transcription control sequences. | a system for the in vivo analysis of fungal transcription control sequences, based on a mini-promoter, was designed. the mini-promoter, providing all sequences necessary and sufficient for transcription initiation, was derived from the aspergillus nidulans gpda promoter region. transcription initiation was not affected by the introduction of transcription control sequences directly upstream from the mini-promoter. furthermore, the expression of the mini-promoter was not affected by wide-domain c ... | 1995 | 7789794 |
| a mutualistic fungal symbiont of perennial ryegrass contains two different pyr4 genes, both expressing orotidine-5'-monophosphate decarboxylase. | a fragment of the claviceps purpurea pyr4 gene, encoding orotidine-5'-monophosphate decarboxylase (omp decarboxylase), was used to screen a genomic library from an isolate of a fungus, acremonium sp. (designated lp1), which grows as an endophyte in perennial ryegrass (lolium perenne). three positive clones, lambda mc11, lambda mc12 and lambda mc14, were isolated. two of these clones, lambda mc12 and lambda mc14, were overlapping clones from the same locus, while lambda mc11 was from a different ... | 1995 | 7789808 |
| crystal structure of isopenicillin n synthase is the first from a new structural family of enzymes. | penicillin antibiotics are all produced from fermentation-derived penicillins because their chemical synthesis is not commercially viable. the key step in penicillin biosynthesis, in which both the beta-lactam and thiazolidine rings of the nucleus are created, is mediated by isopenicillin n synthase (ipns), which binds ferrous iron and uses dioxygen as a cosubstrate. in a unique enzymatic step, with no chemical precedent, ipns catalyses the transfer of four hydrogen atoms from its tripeptide sub ... | 1995 | 7791906 |
| direct analysis of native and chimeric gata specific dna binding proteins from aspergillus nidulans. | in aspergillus nidulans the regulatory gene area is responsible for mediating nitrogen metabolite repression. the area product (area) represents an example of the gata family of dna binding proteins, which are characterised by the presence of a gata domain consisting of a zinc finger within a highly conserved region of 52 amino acids. among the other transcription factors included in this family is the principal erythroid transcription factor, gata-1, which contains two gata domains. in order to ... | 1994 | 7816601 |
| isolation and characterization of an aspergillus nidulans gene encoding an alkaline protease. | we have cloned an aspergillus nidulans gene (prta) encoding an alkaline protease (alp) by probing an a. nidulans library with a fragment amplified from an aspergillus oryzae alp-encoding gene. the nucleotide (nt) sequence of prta was determined. the structure of prta is similar to that of the a. oryzae alp-encoding gene. the prta gene is composed of four exons which are separated by three introns of 59, 57 and 54 nt. the deduced amino acid sequence of the prta product shows a high degree of simi ... | 1994 | 7821793 |
| overexpression of two penicillin structural genes in aspergillus nidulans. | we have placed two different penicillin structural genes from aspergillus nidulans, ipna (encoding isopenicillin n synthetase, ipns) and acya (encoding acyl-coa:6-aminopenicillanic acid acyltransferase, aat), under the control of the strong alca promoter [alca(p)]. single copies of these transcriptional fusions were targeted to the same chromosomal location and conditions have been worked out which simultaneously allow induction of the alca(p) and support penicillin biosynthesis. transcriptional ... | 1995 | 7823906 |
| heterologous expression of the cytotoxin restriction in aspergillus nidulans and aspergillus niger. | the cdna clone of restrictocin was placed under the control of the glucoamylase promoter from aspergillus awamori and was transformed into aspergillus nidulans and aspergillus niger. site-specific changes were introduced into cdna constructs and these were transformed into a. nidulans. the secretion signal sequence was deleted from one form of the gene and three mutations introduced single amino acid substitutions into the protein. culture conditions were optimized for maximum expression levels ... | 1994 | 7827506 |
| overexpression of flba, an early regulator of aspergillus asexual sporulation, leads to activation of brla and premature initiation of development. | aspergillus nidulans reproduces asexually by forming thousands of mitotically derived spores atop highly specialized multicellular organs termed conidiophores. we have identified a gene called flba (for fluffy low brla expression) that is required for initiation of a. nidulans conidiophore development. flba mutants form abnormal colonies that have a distinct fluffy phenotype characterized by tightly interwoven aerial hyphae that autolyse as the colony matures. the requirement for flba in conidio ... | 1994 | 7830576 |
| two new genes involved in signalling ambient ph in aspergillus nidulans. | two new genes, palh and pali, where mutations mimic the effects of acidic growth ph have been identified in aspergillus nidulans. a palh mutation is phenotypically indistinguishable from mutations in the pala, palb, palc, and palf genes, whereas pali mutations differ only in that they allow some growth at ph 8. mutations in pala, b, c, f, and h are epistatic to a pali mutation and the significance of this epistasis is discussed. additionally, pale and palb mutations have been shown to be allelic ... | 1994 | 7830727 |
| the vitamin d3 hydroxylase-associated protein is a propionamide-metabolizing amidase enzyme. | previously we isolated a novel protein that coimmunoprecipitates with the 1,25-dihydroxyvitamin d3-24r-hydroxylase and 25-hydroxyvitamin d3-1 alpha-hydroxylase. this kidney-specific protein found in the inner membrane of mitochondria is named the vitamin d3 hydroxylase-associated protein (vdhap). to determine a putative function for this protein, an extensive computer search of the deduced amino acid sequence of vdhap was performed. a blast homology search identified amino acid residues 133 thro ... | 1995 | 7840608 |
| nitrogen regulation in fungi. | nitrogen regulation has been extensively studied in fungi revealing a complex array of interacting regulatory genes. the general characterisation of the systems in aspergillus nidulans and neurospora crassa shall be briefly described, but much of this paper will concentrate specifically on the recent molecular characterisation of area, the principle regulatory gene from a. nidulans which mediates nitrogen metabolite repression. three areas shall be explored in detail, firstly the dna binding dom ... | 1994 | 7847882 |
| regulatory circuits of the amds gene of aspergillus nidulans. | the amds gene codes for an acetamidase enzyme that hydrolyses acetamide to acetate and ammonium thus providing a. nidulans with a source of carbon and nitrogen. the exceptionally favourable genetics of this system combined with molecular analysis have enabled many regulatory circuits affecting amds to be identified genetically. characterization of the regulatory genes and the definition of the cis-acting sites involved have been done using both in vivo and in vitro mutagenesis. recent results on ... | 1994 | 7847883 |
| expression of genes and processing of enzymes for the biosynthesis of penicillins and cephalosporins. | the genes pcbab, pcbc and pende encoding the enzymes (alpha-aminoadipyl-cysteinyl-valine synthetase, isopenicillin n synthase and isopenicillin n acyltransferase, respectively) involved in the biosynthesis of penicillin have been cloned from penicillin chrysogenum and aspergillus nidulans. they are clustered in chromosome i (10.4 mb) of p. chrysogenum, in chromosome ii of penicillium notatum (9.6 mb) and in chromosome vi (3.0 mb) of a. nidulans. each gene is expressed as a single transcript from ... | 1994 | 7847890 |
| molecular genetics of aspergillus pathogenicity. | aspergillus fumigatus is the most frequent cause of invasive pulmonary aspergillosis (ipa), a life-threatening disease of immunosuppressed patients. in addition to a number of general physiological attributes of this fungus, it has been suggested that extracellular elastase and toxins might facilitate its growth in lung tissue. we have investigated the roles of two extracellular proteins, an alkaline protease with elastase activity (afalp), and the ribotoxin restrictocin in murine models of ipa. ... | 1994 | 7847892 |
| heterologous transformation of zalerion arboricola. | a heterologous dna-mediated transformation system was developed for the pneumocandin-producing fungus z. arboricola that was based on either conferral of hygromycin b resistance or complementation of a nitrate reductase mutant. hygromycin-resistant transformants were selected with plasmid pcsn43 which contains the e. coli hygromycin b phosphotransferase gene under the control of aspergillus nidulans trpc transcription signals. transformation frequencies were about four transformants per microgra ... | 1994 | 7859303 |
| molecular karyotype alterations induced by transformation in aspergillus nidulans are mitotically stable. | clamped homogeneous electric field (chef)-gel electrophoresis was used to define the electrophoretic molecular karyotype of aspergillus nidulans strain oc-1 before and after protoplast-based genetic transformation. the transforming dna caused alterations in the molecular karyotypes in all transformants examined. rather dramatic changes were observed in karyotypes, including apparent chromosome loss, massive size alterations, and the appearance of large chromosomes. changes in molecular karyotype ... | 1994 | 7859304 |
| additive action of partial heterokaryon incompatibility (partial-het) genes in aspergillus nidulans. | we have observed partial heterokaryon-incompatibility reactions in combinations of field isolates of a. nidulans. we have demonstrated that partial heterokaryon incompatibility is genetically controlled by genes (partial-het genes) operating in the same manner as the previously-described het genes. our results also reveal that partial-het genes can act additively in causing heterokaryon incompatibility and that partial heterokaryon incompatibility is not a barrier to the horizontal transfer of a ... | 1994 | 7859306 |
| transformation of botrytis cinerea with the hygromycin b resistance gene, hph. | a transformation method has been developed for the phytopathogenic fungus botrytis cinerea. protoplasts were transformed with pan7-1 plasmid carrying the escherichia coli hygromycin phosphotransferase gene (hph), conferring hygromycin b resistance, downstream from an aspergillus nidulans promoter. molecular analysis, showed that transformation resulted in an integration of the plasmid into different regions of the b. cinerea genome and occurred through non-homologous recombination. the frequency ... | 1994 | 7859308 |
| aspergillus nidulans apsa (anucleate primary sterigmata) encodes a coiled-coil protein required for nuclear positioning and completion of asexual development. | many fungi are capable of growing by polarized cellular extension to form hyphae or by isotropic expansion to form buds. aspergillus nidulans anucleate primary sterigmata (apsa) mutants are defective in nuclear distribution in both hyphae and in specialized, multicellular reproductive structures, called conidiophores. apsa mutations have a negligible effect on hyphal growth, unlike another class of nuclear distribution (nud) mutants. by contrast, they almost completely block entry of nuclei into ... | 1995 | 7860626 |
| myoa of aspergillus nidulans encodes an essential myosin i required for secretion and polarized growth. | we have identified and cloned a novel essential myosin i in aspergillus nidulans called myoa. the 1,249-amino acid predicted polypeptide encoded by myoa is most similar to the amoeboid myosins i. using affinity-purified antibodies against the unique myosin i carboxyl terminus, we have determined that myoa is enriched at growing hyphal tips. disruption of myoa by homologous recombination resulted in a diploid strain heterozygous for the myoa gene disruption. we can recover haploids with an intact ... | 1995 | 7860631 |
| molecular similarity matrices and quantitative structure-activity relationships: a case study with methodological implications. | recently, statistical analysis of molecular similarity matrices has been applied to the quantitative structure-activity relationship (qsar) analysis of a number of molecular series. this paper addresses a number of methodological issues relative to the similarity matrices. a series of halogenated aliphatic hydrocarbons, for which the mutation (aneuploidy) induction ability had previously been determined, was used as test bench. the chemical information carried by the similarity matrices was show ... | 1995 | 7861411 |
| gene inactivation in the plant pathogen glomerella cingulata: three strategies for the disruption of the pectin lyase gene pnla. | the feasibility of performing routine transformation-mediated mutagenesis in glomerella cingulata was analysed by adopting three one-step gene disruption strategies targeted at the pectin lyase gene pnla. the efficiencies of disruption following transformation with gene replacement- or gene truncation-disruption vectors were compared. to effect replacement-disruption, g. cingulata was transformed with a vector carrying dna from the pnla locus in which the majority of the coding sequence had been ... | 1995 | 7862090 |
| yeast proteins can activate expression through regulatory sequences of the amds gene of aspergillus nidulans. | the upstream regulatory region of the amds gene of aspergillus nidulans contains a ccaat sequence known to be important in setting both basal and depressed levels of expression. we have investigated whether the ccaat-binding hap2/3/4 complex of the yeast saccharomyces cerevisiae can recognise this sequence in an amds context. sequences from the 5' region of amds were cloned in front of the cyc1-lacz fusion gene bearing a minimal promoter and transformed into wild-type and hap2 strains of yeast. ... | 1995 | 7862093 |
| glucose-induced inactivation of isocitrate lyase in aspergillus nidulans. | the existence of a second mechanism of catabolite control of isocitrate lyase of aspergillus nidulans, in addition to the carbon catabolite repression phenomenon recently reported was analysed. isocitrate lyase was rapidly and specifically inactivated by glucose. the inactivation was irreversible at all stages in the presence of cycloheximide, showing that reactivation depends on de novo protein synthesis. in addition, analysis of glucose-induced inactivation of isocitrate lyase in a cread-30 st ... | 1994 | 7872837 |
| extracellular arabinases in aspergillus nidulans: the effect of different cre mutations on enzyme levels. | the regulation of the syntheses of two arabinan-degrading extracellular enzymes and several intracellular l-arabinose catabolic enzymes was examined in wild-type and carbon catabolite derepressed mutants of aspergillus nidulans. alpha-l-arabinofuranosidase b, endoarabinase, l-arabinose reductase, l-arabitol dehydrogenase, xylitol dehydrogenase, and l-xylulose reductase were all inducible to varying degrees by l-arabinose and l-arabitol and subject to carbon catabolite repression by d-glucose. wi ... | 1994 | 7872840 |
| the use of electrospray mass spectrometry to identify an essential arginine residue in type ii dehydroquinases. | the arginine-specific reagent phenylglyoxal has been used to identify a hyper-reactive arginine residue which is essential for activity in the type ii dehydroquinases of streptomyces coelicolor and aspergillus nidulans. electrospray mass spectrometry was used both to characterise the phenylglyoxal modified protein, and to identify the phenylglyoxal modified peptides following enzymatic digestion. the advantages of using electrospray mass spectrometry for monitoring arginine modication aimed at i ... | 1995 | 7875309 |
| transformation of aspergillus nidulans by microprojectile bombardment on intact conidia. | this paper describes transformation of intact conidia of aspergillus nidulans, auxotrophic for arginine, by using the biolistic process. the plasmid employed was pfb39, carrying the argb gene. the transformation frequency obtained was 81 transformants/microgram of dna. classical genetics and molecular analysis were conducted to analyse transformants and to determine in which chromosome integration took place. | 1995 | 7875577 |
| cloning and molecular characterization of hxa, the gene coding for the xanthine dehydrogenase (purine hydroxylase i) of aspergillus nidulans. | we have cloned and sequenced the hxa gene coding for the xanthine dehydrogenase (purine hydroxylase i) of aspergillus nidulans. the gene codes for a polypeptide of 1363 amino acids. the sequencing of a nonsense mutation, hxa5, proves formally that the clones isolated correspond to the hxa gene. the gene sequence is interrupted by three introns. similarity searches reveal two iron-sulfur centers and a nad/fad-binding domain and have enabled a consensus sequence to be determined for the molybdenum ... | 1995 | 7876088 |
| cointegration of transforming dnas in aspergillus nidulans: a model using autonomously-replicating plasmids. | transforming dnas form cointegrates in aspergillus nidulans by homologous and non-homologous recombination as well as by end-to-end ligation of linear fragments. this process has been studied by means of a model in which the linkage of a marker gene to the origin of autonomous replication ama1 was selected for. recombinant plasmids were rescued into escherichia coli and subjected to restriction mapping and sequence analysis. it was shown that circular dna molecules recombined predominantly withi ... | 1994 | 7882430 |
| the aspergillus pacc zinc finger transcription factor mediates regulation of both acid- and alkaline-expressed genes by ambient ph. | the ph regulation of gene expression in aspergillus nidulans is mediated by pacc, whose 678 residue-derived protein contains three putative cys2his2 zinc fingers. ten paccc mutations mimicking growth at alkaline ph remove between 100 and 214 c-terminal residues, including a highly acidic region containing an acidic glutamine repeat. nine pacc+/- mutations mimicking acidic growth conditions remove between 299 and 505 c-terminal residues. deletion of the entire pacc coding region mimics acidity bu ... | 1995 | 7882981 |
| flbd encodes a myb-like dna-binding protein that coordinates initiation of aspergillus nidulans conidiophore development. | the timing of asexual fruiting body formation during aspergillus nidulans colony development is precisely regulated so that conidiophores are typically produced 1-2 mm behind the growing edge of the colony. mutations in any of four a. nidulans genes, flbb, flbc, flbd, or flbe, result in colonies that are delayed at least 24 hr in their ability to initiate conidiophore development resulting in fluffy colonies with conidiophores forming in the center, at least 12-15 mm behind the growing edge. the ... | 1995 | 7883170 |
| amino acid transporters of lower eukaryotes: regulation, structure and topogenesis. | lower eukaryotes such as the yeast saccharomyces cerevisiae and the filamentous fungus aspergillus nidulans possess a multiplicity of amino acid transporters or permeases which exhibit different properties with respect to substrate affinity, specificity, capacity and regulation. regulation of amino acid uptake in response to physiological conditions of growth is achieved principally by a dual mechanism; control of gene expression, mediated by a complex interplay of pathway-specific and wide-doma ... | 1995 | 7888172 |
| the nima protein kinase is hyperphosphorylated and activated downstream of p34cdc2/cyclin b: coordination of two mitosis promoting kinases. | initiation of mitosis in aspergillus nidulans requires activation of two protein kinases, p34cdc2/cyclin b and nima. forced expression of nima, even when p34cdc2 was inactivated, promoted chromatin condensation. nima may therefore directly cause mitotic chromosome condensation. however, the mitosis-promoting function of nima is normally under control of p34cdc2/cyclin b as the active g2 form of nima is hyperphosphorylated and further activated by p34cdc2/cyclin b when cells initiate mitosis. to ... | 1995 | 7889944 |
| mitotic destruction of the cell cycle regulated nima protein kinase of aspergillus nidulans is required for mitotic exit. | nima is a cell cycle regulated protein kinase required, in addition to p34cdc2/cyclin b, for initiation of mitosis in aspergillus nidulans. like cyclin b, nima accumulates when cells are arrested in g2 and is degraded as cells traverse mitosis. however, it is stable in cells arrested in mitosis. nima, and related kinases, have an n-terminal kinase domain and a c-terminal extension. deletion of the c-terminus does not completely inactivate nima kinase activity but does prevent functional compleme ... | 1995 | 7889945 |
| starvation stress modulates the expression of the aspergillus nidulans brla regulatory gene. | expression of the aspergillus nidulans brla gene plays a fundamental role in the switch from vegetative growth to asexual reproduction. using a media-shifting protocol to induce submerged sporulation and brla-lacz as an expression marker, it was shown that carbon and nitrogen starvation stress induced brla transcription to different degrees. glucose starvation induced bria rapidly to high levels and resulted in spore formation on reduced conidiophores, whereas nitrogen starvation induced brla gr ... | 1995 | 7894714 |
| carbon regulation of penicillin biosynthesis in aspergillus nidulans: a minor effect of mutations in creb and crec. | transcription of the aspergillus nidulans ipna gene is under carbon regulation. loss-of-function mutations in creb or crec do not cause full derepression of ipna transcript levels in sucrose-grown mycelia and do not elevate repressed penicillin levels, indicating that neither of these genes plays a major regulatory role in penicillin biosynthesis. however, these mutations reduce external ph acidification, accelerate sucrose degradation and result in extracellular accumulation of resulting d-gluc ... | 1995 | 7896078 |
| site-directed mutagenesis of nitrate reductase from aspergillus nidulans. identification of some essential and some nonessential amino acids among conserved residues. | nitrate reductase is a multiredox enzyme possessing three functional domains associated with the prosthetic groups fad, heme iron, and molybdopterin. in aspergillus nidulans, it is encoded by the niad gene. a homologous transformation system has been used whereby a major deletion at the niianiad locus of the host was repaired by gene replacement. employing site-directed mutagenesis and this transformation system, nine niad mutants were generated carrying specific amino acid substitutions. mutant ... | 1995 | 7896804 |
| sexual origins of british aspergillus nidulans isolates. | aspergillus nidulans is a holomorphic fungus, capable of producing both meiotically and mitotically derived spores. meiosis may be an evolutionary relic in this species because it is potentially capable of mitotic recombination and because most aspergilli lack the ability to produce meiotic spores. we tested the null hypothesis that meiosis has been a major factor in the origin of strains of a. nidulans from great britain by estimating linkage disequilibrium among restriction fragment length pol ... | 1994 | 7907796 |
| isolation of the faca (acetyl-coa synthetase) gene of phycomyces blakesleeanus. | a 5.6 kb dna fragment from the fungus phycomyces blakesleeanus has been cloned and sequenced. the fragment contains a gene that probably codes for the enzyme acetyl-coenzyme a synthetase (faca). the amino acid sequence deduced for the p. blakesleeanus protein is highly homologous to those of acetyl-coa-synthetases from other organisms. when placed under the control of a constitutive promoter from aspergillus nidulans, the cloned gene complemented a faca- mutation of this organism. in p. blakesle ... | 1994 | 7914670 |
| assignment of rflp, rapd and isoenzyme markers to aspergillus nidulans chromosomes, using chromosome-substituted segregants of a hybrid of a. nidulans and a. quadrilineatus. | chromosome-substituted haploid segregants were selected from among the benomyl-induced progeny of an interspecific hybrid produced by polyethylene-glycol-induced fusion of protoplasts of an aspergillus nidulans 'master strain' and an a. quadrilineatus auxotrophic mutant. these segregants were examined by rflp, rapd, and isoenzyme analysis. the a. nidulans ribosomal repeat unit was assigned to chromosome v, while the bena and the pyrg genes were assigned to linkage groups viii and i, respectively ... | 1994 | 7915967 |
| characterization of an aspergillus nidulans genomic dna fragment conferring phosphate-non-repressible acid-phosphatase activity. | a clone from an aspergillus nidulans library was identified by its ability to confer enhanced staining for acid phosphatase (apase) activity upon phosphatase-deficient a. nidulans mutants. this apase activity is not repressed by high phosphate concentrations in the medium. the 2.9-kb nucleotide sequence in the region of the clone responsible for the effect reveals two potential protein-coding genes with a common n terminus. one corresponds to an open reading frame (orf) with no introns, encoding ... | 1993 | 7916713 |
| isolation and characterization of cdna and genomic promoter region for a heat shock protein 30 from aspergillus nidulans. | a cdna encoding for a heat shock protein 30 (hsp30) of aspergillus nidulans and the promoter region of its gene were analyzed for their primary structures. the promoter region had no heat shock element but possessed three inverted repeat sequences. northern blot hybridization indicated that the expression of the hsp30 gene was high at a normal temperature and was slightly accelerated at elevated temperatures in a. nidulans cells. although the deduced amino acid sequence of the a. nidulans hsp30 ... | 1994 | 7918658 |
| mitochondrial dna restriction fragment length polymorphisms in field isolates of the aspergillus niger aggregate. | the mitochondrial dnas (mtdnas) and the ribosomal repeat unit (ribosomal dna, rdna) of black aspergillus isolates collected in various parts of the world were examined. wide-ranging mtdna variation was observed in natural populations of the aspergillus niger aggregate. most isolates were classifiable as a. niger or aspergillus tubingensis according to their rdna and mtdna patterns. the mtdna variation was distributed unevenly in the populations studied. the mtdnas of most of the isolates collect ... | 1994 | 7922884 |
| phenotypic and epistatic grouping of hypo- and hyper-rec mus mutants in aspergillus. | the mutants musk to muss of aspergillus nidulans are sensitive to methyl-methanesulfonate (mms) and several of them are meiotic-defective and alter mitotic recombination frequencies. all were found to be cross-sensitive to 4-nitro-quinoline-n-oxide (4-nqo) but unexpectedly none of them was hypersensitive to gamma-rays and few to uv light. double mus; uvs mutants were constructed to test for interactions with uvs mutations of the four epistatic groups of aspergillus, "uvsf", "uvsc", "uvsi", and " ... | 1994 | 7923408 |
| the aspergillus nidulans flug gene is required for production of an extracellular developmental signal and is related to prokaryotic glutamine synthetase i. | mutations in the aspergillus nidulans flug gene disrupt the programmed induction of asexual sporulation and result in formation of fluffy colonies that are characterized by undifferentiated cotton-like masses of vegetative cells. we show that the flug mutant phenotype is suppressed when flug mutant colonies are grown next to wild-type colonies even if the two strains are separated by dialysis membrane with a 6000- to 8000-dalton pore size. flug encodes a cytoplasmically localized approximately 9 ... | 1994 | 7926755 |
| rodletless mutants of aspergillus fumigatus. | conidia of aspergillus fumigatus adhere in vitro to host proteins and cells via the outer cell wall layer. the roda gene of a. fumigatus was cloned by homology with the roda gene of aspergillus nidulans, which is involved in the structure of the rodlets characteristic of the surface layer. the a. fumigatus roda protein sequence has 85% similarity to that of a. nidulans roda; the sequence codes for a hydrophobin, a low-molecular-weight protein moderately hydrophobic and rich in cysteines. the gen ... | 1994 | 7927699 |
| hyp1, a hydrophobin gene from aspergillus fumigatus, complements the rodletless phenotype in aspergillus nidulans. | aspergillus fumigatus produces conidia that are highly dispersable and resistant to degradation. we have sought to analyze these properties by studying the rodlets which form the outer spore coat protein. degenerate primers based on hydrophobins in other fungi were applied to genomic dna from a. fumigatus in pcr. a product of this reaction with similarity to an aspergillus nidulans gene as judged by southern hybridization was chosen for further study. cloning and sequencing revealed a gene with ... | 1994 | 7927700 |
| a novel murine gene encoding a 216-kda protein is related to a mitotic checkpoint regulator previously identified in aspergillus nidulans. | we describe the isolation and characterization of a novel mouse gene, tsg24, which displays striking sequence similarities to the aspergillus nidulans bime gene. the bime gene has been shown to be a mitotic checkpoint regulator, negatively regulating entry into mitosis in a. nidulans. the tsg24 gene was found to contain a long open reading frame of 1944 amino acids, encoding a polypeptide with a calculated molecular mass of 216,087 da. we have developed an antibody directed against the product o ... | 1994 | 7929068 |
| general primer-mediated pcr for detection of aspergillus species. | a pcr assay was developed for the diagnosis of invasive aspergillosis in immunocompromised patients. for this purpose, the complete nucleotide sequences of the genes encoding the 18s rrna of aspergillus nidulans, aspergillus terreus, aspergillus niger, and aspergillus flavus were elucidated and aligned to the sequences of aspergillus fumigatus and other clinically relevant prokaryotic and eukaryotic microorganisms. genus-specific sequences could be identified in the v7 to v9 region of 18s rrna. ... | 1994 | 7929762 |
| the omps gene of vibrio cholerae encodes a growth-phase-dependent maltoporin. | the outer membrane of vibrio cholerae contains a maltose-inducible major protein, omps (43 kda), that is common to different isolates. nucleotide sequence analysis of the corresponding structural gene, omps, revealed an open reading frame encoding a 412-amino-acid polypeptide. the amino acid sequence of omps is similar to that of lamb, the escherichia coli maltoporin, and to scry or klebsiella pneumoniae, although the antigenic determinants of these proteins are different. the cloned omps gene c ... | 1993 | 7934851 |
| a study of the alkaline proteases secreted by different aspergillus species. | strains from several species of aspergillus were grown in the presence of soluble collagen, and the major secreted proteins present in the culture fluid were examined for proteolytic activity. the possibility of relatedness among the alkaline proteases secreted by aspergillus was studied by probing extracts from the various species with polyclonal antisera raised to the isolated alkaline proteases of a. fumigatus and a. oryzae. the pathogenic species a. flavus, a. terreus and a. nidulans hydroly ... | 1993 | 7935565 |
| high-level expression of human superoxide dismutase in the cyanobacterium anacystis nidulans 6301. | a chemically synthesized gene encoding human cuzn superoxide dismutase (hsod) was cloned into the shuttle vector pbax18r and expressed in anacystis nidulans 6301 (synechococcus sp. strain pcc 6301) under the control of a ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbc) promoter derived from a. nidulans 6301. the sequences immediately upstream from the hsod coding region and the distances between the ribosomal binding site and atg initiation codon strongly affected the expression of the ... | 1994 | 7937873 |
| rescue of yeast defective in mitochondrial atp synthase subunit 8 by a heterologous gene from aspergillus nidulans. | mitochondrial atp synthase subunit 8 of the yeast saccharomyces cerevisiae and of the filamentous fungus aspergillus nidulans have the same length and similar structural motifs. however, the two proteins share only 50% identical residues, with the conserved residues being concentrated in the n- and c-terminal domains. we have investigated whether it is amino acid sequence or overall structural motifs that are required for subunit 8 function. pcr was used to construct a gene encoding a. nidulans ... | 1994 | 7945306 |
| an analysis of the sequence of part of the right arm of chromosome ii of s. cerevisiae reveals new genes encoding an amino-acid permease and a carboxypeptidase. | we have analysed two new genes, ybr1007 and ybr1015, discovered during the systematic sequencing of chromosome ii of s. cerevisiae. ybr1007 shows strong similarities to amino-acid permeases, in particular the high-affinity proline permeases of s. cerevisiae and a. nidulans. the number and position of the predicted membrane-spanning domains suggest a conserved structure for these proteins, with 12 trans-membrane domains. ybr1015 shows strong similarities to serine carboxypeptidases; all three res ... | 1994 | 7954890 |
| premature chromatin condensation upon accumulation of nima. | the nima protein kinase of aspergillus nidulans is required for the g2/m transition of the cell cycle. mutants lacking nima arrest without morphological characteristics of mitosis, but they do contain an activated p37nimx kinase (the aspergillus homologue of p34cdc2). to gain a better understanding of nima function we have investigated the effects of expressing various nima constructs in aspergillus, fission yeast and human cells. our experiments have shown that the instability of the nima prote ... | 1994 | 7957060 |
| a cosmid with a hyr marker for fungal library construction and screening. | the construction of a double-cos-site cosmid vector, pmocosx, for use in making filamentous fungal genomic dna libraries, is described. the vector has features that allow for selection of clones introduced into fungi by transformation and for efficient chromosome walking experiments. these features include (i) two cos sites allowing for easy construction of libraries without requiring size selection of insert dna; (ii) an xhoi site for insertion of sau3ai or mboi partially digested genomic dna i ... | 1994 | 7959044 |
| virulence studies of aspergillus nidulans mutants requiring lysine or p-aminobenzoic acid in invasive pulmonary aspergillosis. | to identify steps in fungal intermediary metabolism required by aspergillus spp. during invasive pulmonary aspergillosis, we have developed murine models involving aspergillus nidulans as the inoculum. the advantages of using a. nidulans over aspergillus fumigatus or aspergillus flavus, which are the most common agents of clinical disease, are the well-understood genetics of a. nidulans and a large range of mutants of this species which are affected in a variety of metabolic pathways. comparison ... | 1994 | 7960102 |
| a single p34cdc2 protein kinase (encoded by nimxcdc2) is required at g1 and g2 in aspergillus nidulans. | we have cloned and sequenced a homolog of cdc2 from aspergillus nidulans that can complement the schizosaccharomyces pombe cdc2-33 mutation. the gene was deleted and is required for continued nuclear dna replication but not for mitochondrial dna replication. three different temperature-sensitive alleles were generated by reverse genetics. all of the mutations generate the nim phenotype of a. nidulans. the new gene was designated nimxcdc2 as it is not allelic to any of the other nim genes (nima t ... | 1994 | 7962194 |
| oxygen requirements of aspergillus species. | the growth of 24 aspergillus isolates at low oxygen tensions was assessed. isolates selected included a. fumigatus (10), a. terreus (6), a. niger (6), a. nidulans (1) and a. flavus (1). three different agar media were used--potato dextrose agar (pda), ph 5.6; brain heart infusion (bhi), ph 7.4; and a specially developed medium (hall's) containing resazurin--with oxygen concentrations of 0, 0.025, 0.1, 0.5 and 2.5%. the co2 concentration was 5%. agar plates were inoculated with 2 x 10(7) conidia/ ... | 1994 | 7966201 |
| a fast random cost algorithm for physical mapping. | ordering clones from a genomic library into physical maps of whole chromosomes presents a central computational/statistical problem in genetics. here we present a physical mapping algorithm for creating ordered genomic libraries or contig maps by using a random cost approach [berg, a. (1993) nature (london) 361, 708-710]. this random cost algorithm is 5-10 times faster than existing physical mapping algorithms and has optimization performance comparable to existing procedures. the speedup in the ... | 1994 | 7972016 |
| serological survey of infections in waterfowl in the guadalquivir marshes (spain). | a serological survey was performed in the guadalquivir marshes (southern spain) in order to determine the presence and diffusion of six infective agents in wild waterfowl. the analysis covered 712 waterfowl from 13 species belonging to five taxa (podicipediformes, ciconiiformes, anseriformes, gruiformes, and charadriiformes). a range of immunological techniques led to detection of antibodies against the six infective agents studied: chlamydia psittaci (13.3%), mycoplasma anatis (3.5%), pasteurel ... | 1994 | 7980291 |
| germinating conidiospores of aspergillus amino acid auxotrophs are hypersensitive to heat shock, oxidative stress and dna damage. | germinating conidiospores (conidia) of aspergillus nidulans amino acid-requiring strains are hypersensitive to heat, oxidative stress, uv radiation and chemical mutagens when compared with other strains. they also showed an increased mutation rate. sensitivity to stress conditions has been correlated with an abnormal ras/camp pathway in mutants of s. cerevisiae. we suggest that the ras/camp pathway is defective in germinating conidia of aspergillus amino acid auxotrophs and that this is responsi ... | 1994 | 7982501 |
| bidirectional gene transfer between aspergillus fumigatus and aspergillus nidulans. | a genomic dna library was constructed from a pathogenic strain of aspergillus fumigatus using the cosmid vector pcosax. cosmid clones with homologies to the roda, brla, flug, flba or trpc genes from a. nidulans were isolated from the library. each a. fumigatus clone was used to complement a strain of a. nidulans with a mutation in the homologous gene. a spontaneous white spored strain of a. fumigatus was isolated. the mutation was complemented by transforming the strain with a plasmid containing ... | 1994 | 7988865 |
| transcriptional regulation of the trichoderma longibrachiatum egl1 gene. | transcription of the trichoderma longibrachiatum egl1 gene is induced in the presence of lactose and beta-methylglucoside and repressed by glucose. a dna fragment containing 722 bp upstream of the atg codon has been sequenced. the gene has two major transcription start points (20 and 24 nucleotides upstream from the atg codon) and several transcription termination points (located in a region around 130 nt downstream of the stop codon). two 6-mer sequences (5'-ctggag-3') separated by 16 bp are pr ... | 1994 | 7988872 |
| characterization of an aspergillus nidulans l-arabitol dehydrogenase mutant. | the degradation pathway for l-arabinose, which consists of a sequence of alternating reduction and oxidation reactions prior to ultimate phosphorylation, was studied in aspergillus nidulans wild-type as well as in an l-arabinose non-utilizing mutant. the inability of the mutant to use l-arabinose was caused by the absence of l-arabitol dehydrogenase activity. the effect of the mutation on polyol accumulation patterns was studied upon growth on various carbon sources. the presence of l-arabinose ... | 1994 | 7988903 |
| highly-efficient transformation of the homobasidiomycete schizophyllum commune to phleomycin resistance. | regulatory sequences of the glyceraldehyde-3-phosphate-dehydrogenase (gpd) gene from the homobasidiomycete schizophyllum commune were fused to the coding sequence of the ble gene from streptoalloteichus hindustanus, which codes for a phleomycin-binding protein. the resulting construct transformed s. commune to phleomycin resistance at a high frequency (up to 10(4) transformants/microgram dna per 10(7) protoplasts) when regeneration was done in 0.5 m mgso4. a similar construct with regulatory seq ... | 1994 | 8001174 |
| transformation of aspergillus parasiticus using autonomously replicating plasmids from aspergillus nidulans. | a genetic transformation system for the aflatoxin-producing fungus aspergillus parasiticus using two autonomously replicating plasmids from a. nidulans (arp1 and pdhg25) is reported. transformation frequencies using the plasmid pdhg25 were from 5 x 10(2) to 2.5 x 10(4) transformants per 10(6) viable protoplasts and microgram dna. the stability of the plasmids in the transformants was also studied. this transformation system offers a new opportunity to clone genes related to aflatoxin production ... | 1994 | 8001767 |
| evolution of cytochrome oxidase, an enzyme older than atmospheric oxygen. | cytochrome oxidase is a key enzyme in aerobic metabolism. all the recorded eubacterial (domain bacteria) and archaebacterial (archaea) sequences of subunits 1 and 2 of this protein complex have been used for a comprehensive evolutionary analysis. the phylogenetic trees reveal several processes of gene duplication. some of these are ancient, having occurred in the common ancestor of bacteria and archaea, whereas others have occurred in specific lines of bacteria. we show that eubacterial quinol o ... | 1994 | 8013452 |
| the calmodulin-dependent protein phosphatase catalytic subunit (calcineurin a) is an essential gene in aspergillus nidulans. | the gene encoding the homologue of the catalytic subunit of the ca2+/calmodulin-regulated protein phosphatase 2b (calcineurin a) has been isolated from aspergillus nidulans. this gene, cnaa+, is essential in this fungal system. analysis of growth-arrested cells following gene disruption by homologous recombination reveals that they are blocked early in the cell cycle. the cnaa+ gene encodes a 2.5 kb mrna and the deduced protein sequence is highly homologous to the calcineurin a subunit of other ... | 1994 | 8013455 |
| aspergillus nidulans vera is required for production of the mycotoxin sterigmatocystin. | aspergillus nidulans produces the carcinogenic mycotoxin sterigmatocystin (st), the next-to-last precursor in the aflatoxin (af) biosynthetic pathway found in the closely related fungi aspergillus flavus and aspergillus parasiticus. we identified and characterized an a. nidulans gene, vera, that is required for converting the af precursor versicolorin a to st. vera is closely related to several polyketide biosynthetic genes involved in polyketide production in streptomyces spp. and exhibits exte ... | 1994 | 8017929 |
| evidence for a h+ nitrate symporter in aspergillus nidulans. | nitrate transport in aspergillus nidulans was dependent upon a consistent proton motive force (delta p) across the cell membrane which was maintained in a range of 105 (+/- 6.7) to 131 (+/- 3.4) mv over an external ph span of 5.5 to 7.5. the membrane potential (delta psi) measured by uptake of [3h]-tetra-phenylphosphonium bromide and the transmembrane ph difference (delta ph) measured by the distribution of 3h2o and [14c]- salicylic acid were used to compute the delta p present during transport ... | 1994 | 8022307 |
| mutants of aspergillus nidulans deficient in nuclear migration during hyphal growth and conidiation. | anucleate primary sterigmata (aps) mutants of aspergillus nidulans are partially blocked in conidiation (asexual sporulation) due to failure of the organized migration of nuclei into the conidiophore metulae. the mutants also have a slightly reduced hyphal growth rate and irregular distribution of nuclei in vegetative hyphae; the hyphal phenotype appears somewhat more variable than the conidiation defect. the mutants fall into two complementation groups, apsa and apsb, mapping on chromosomes iv ... | 1994 | 8025681 |
| analysis of the regulation of the aspergillus nidulans acud gene, encoding isocitrate lyase, by construction of a hybrid promoter. | in order to confirm functionally that a 208 bp fragment of the 5'-flanking sequence of the acud gene of aspergillus nidulans is the region responsible for acetate inducibility and catabolite repression, a hybrid promoter was constructed by insertion of this fragment into the promoter of the (highly expressed) olic gene of a. nidulans. analysis of expression of the lacz reporter gene fused to the olic/acud promoter showed induction by acetate at much higher levels than wild-type acud expression. ... | 1994 | 8028581 |
| evolutionary conservation of the transcribed spacer sequences of the rdna repeat unit in three species of the genus aspergillus. | we have cloned and sequenced the two intervening transcribed spacers in the rdna repeat unit of three aspergillus species--a. nidulans, a. awamori and a. wentii. the a. wentii and a. awamori spacers are almost identical and share a high degree of homology with the a. nidulans spacers. all spacers have a high g-c content (66%-76%) and the potential of forming complex secondary structures, which may indicate that they play a role in the maturation of pre-rrna molecules. | 1994 | 8030378 |
| developmental decisions in aspergillus nidulans are modulated by ras activity. | to better understand how ras controls development of multicellular organisms, we have chosen aspergillus nidulans as a model system. when grown on solid medium, this fungus follows a well-defined program of development, sequentially giving rise to several cell types which produce three distinct structures: vegetative hyphae, aerial hyphae, and the conidiophore structure. here we describe a ras homolog found in this fungus (aras) and demonstrate that it is an essential gene that regulates the ord ... | 1994 | 8035812 |