PMID(sorted descending)
sequence, regulation, and mutational analysis of the gene encoding urate oxidase in aspergillus nidulans.the uaz gene of aspergillus nidulans codes for a protein of 301 amino acids. the open reading frame is interrupted by two introns. a comparison with the open reading frames of 10 other urate oxidases reveals a number of scattered universally conserved residues and four clusters of high similarity. two of these are of unknown function, and the other two are the putative sites for copper binding and the signal sequence for peroxisomal entry, respectively. this comparison also reveals that there ar ...19938226863
sequence and regulation of the uapa gene encoding a uric acid-xanthine permease in the fungus aspergillus nidulans.the nucleotide sequence of the uapa gene, coding for the uric acid-xanthine permease of aspergillus nidulans, has been determined. the predicted uapa gene product comprises 595 amino acids (m(r) 63,365); it is a highly hydrophobic protein with 12-14 putative transmembrane segments and shows no striking similarity to any other membrane protein of either prokaryotes or eukaryotes, except for a short highly hydrophobic amino acid sequence conserved in a number of different permeases. the presence o ...19938226862
a novel phage lambda replacement cre-lox vector that has automatic subcloning capabilities.we have developed a novel phage lambda replacement cloning vector, lambda pan. lambda pan allows one to automatically subclone the insert as a plasmid using the cre-loxp site-specific recombination system. this eliminates the need to subclone insert fragments and permits the rapid structural analysis of insert dna. lambda pan is similar to other phage lambda replacement vectors taking inserts ranging in size from 5 to 19 kb. we have placed the pyrg gene of aspergillus nidulans on the vector as a ...19938224901
heterologous protein secretion directed by a repressible acid phosphatase system of aspergillus niger.a new expression-secretion system of aspergillus niger which directs the secretion of heterologous proteins is described. the promoter and signal peptide-encoding region of the phosphate-repressible apha gene of a. niger, when fused to the coding region of the human interferon alpha 2 (hifn alpha 2)-encoding gene (hifn alpha 2), drives the expression of this gene and the secretion of the hifn alpha 2 protein. synthesis of hifn alpha 2 in either a. niger or a. nidulans transformants carrying thes ...19938224863
characterisation, cloning and integrative properties of the gene encoding urate oxidase in aspergillus nidulans.a number of mutations have been obtained which define the structural gene (uaz) coding for urate oxidase in linkage group i of aspergillus nidulans. this gene has been cloned by transformation of a uaz- null mutant. a chromosome i/viii translocation which splits the gene has been defined both genetically and physically. all known mutations are contained in a 1-kb fragment, itself contained in the probe which recognizes a 1.2-kb inducible message. plasmids carrying uaz show a strict bias towards ...19938224862
galactose oxidase: molecular analysis and mutagenesis studies. 19938224504
preliminary studies of two active site mutants of galactose oxidase. 19938224464
heat resistance of fungi from soil.the survival of fungi from soil samples has been investigated after exposure to temperatures of 60, 70, 80 and 90 degrees c in sabouraud agar. the least resistant fungi surviving 60 degrees c for 60 min were the aspergillus (a.) niger group, chaetomium spp, penicillium spp, and scytalidium lignicola. none of these survived 70 degrees c for 10 min. the next group surviving 70 degrees c for 60 min included the a. glaucus group, byssochlamys nivea, dichotomomyces cejpii, gelasinospora spp, rhizocto ...19938217516
the avr9 race-specific elicitor of cladosporium fulvum is processed by endogenous and plant proteases.the avirulence gene avr9 of the fungal tomato pathogen cladosporium fulvum encodes a race-specific peptide elicitor that induces a hypersensitive response in tomato plants carrying the complementary resistance gene cf9. the avr9 gene is highly expressed when c. fulvum is growing in the plant and the elicitor accumulates in infected leaves as a 28-amino acid (aa) peptide. in c. fulvum grown in vitro, the peptide elicitor is not produced in detectable amounts. to produce significant amounts of the ...19938208859
expression of the 3-phosphoglycerate kinase gene (pgka) of penicillium chrysogenum.the sequence of the penicillium chrysogenum pgka gene promoter was determined up to 952 nucleotides (nt) 5' to the major transcriptional start point (position +1), and contains a 38 bp pyrimidine-rich region within which transcription initiates at this and two minor sites (-11, -23). a 21 bp segment (-99 to -79) closely matches a region which is essential for the expression of the aspergillus nidulans pgka gene. a further region was found with similarity to sequences in other a. nidulans promote ...19948190080
variability of aspergillus nidulans antigens with media and time and temperature of growth.the influence of culture medium and time and temperature of growth on the appearance of aspergillus nidulans antigens was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by silver staining or western blot (immunoblot), of the proteins present in total cellular extracts or culture supernatants. samples in the exponential, deceleration, and stationary growth phases were selected by biochemical, morphological, and ultrastructural criteria. protein and antigen patte ...19948188355
expression of the noncatalytic domain of the nima kinase causes a g2 arrest in aspergillus nidulans.temperature-sensitive mutation of the nima gene of aspergillus nidulans causes a reversible g2 arrest, whereas overexpression of nima causes premature entry into mitosis from which the cells cannot exit. the nima gene encodes a ser/thr-specific protein kinase (nima) which contains an extended cooh-terminal noncatalytic domain. to evaluate the role of this enzyme in nuclear division control, we introduced various mutant nima cdnas under the control of the inducible alcohol dehydrogenase gene prom ...19948187763
identification of nitrate transporter genes in chlamydomonas reinhardtii.the chlamydomonas reinhardtii nar-2, nar-3, and nar-4 genes, which are within a nitrate-regulated gene cluster containing the nitrate reductase structural gene nit-1, have been related to nitrate transport. mutant strains defective in nitrate transport and having an active nitrate reductase have been genetically constructed. their nitrate non-utilizing phenotype has been directly complemented by transformation using the pco-5 plasmid which carries the nar-2, nar-3, and nar-4 clustered genes. int ...19948180624
characterization of a 3-dehydroquinase gene from actinobacillus pleuropneumoniae with homology to the eukaryotic genes qa-2 and qute.a gene was cloned from actinobacillus pleuropneumoniae strain 4074 by complementation of an arod strain of escherichia coli. the e. coli gene arod codes for a 3-dehydroquinase enzyme of type i, active in the aromatic biosynthesis pathway. the a. pleuropneumoniae gene, termed aroq, displays no base or amino acid sequence homology to arod of e. coli. it is instead homologous to the qute and qa-2 genes, respectively of aspergillus nidulans and neurospora crassa. these genes code for 3-dehydroquinas ...19948170389
microtubule organizing centers and gamma-tubulin.the polar assembly of cellular microtubules is organized by microtubule organizing centers (mtocs). eukaryotic cells across different species, and different cell types within single species, have morphologically diverse mtocs, which have the common function of organizing microtubule arrays by initiating microtubule assembly and anchoring microtubules by their slow-growing 'minus' ends, thus ensuring that the rapidly growing 'plus' ends extend distally. the past few years have witnessed a variety ...19948167026
homology at the amino acid level between plant phytochromes and a regulator of asexual sporulation in emericella (= aspergillus) nidulans.protein sequence comparison between the n-terminal regions of the brla (bristle a) protein of the ascomycete fungus aspergillus nidulans and a number of plant phytochromes has demonstrated a moderate level of sequence similarity. the region of similarity corresponds to the phytochrome domains believed to be responsible for photoreception and which undergo light-induced conformational changes, although a putative chromophore-binding site is not evident. over 22% of residues are conserved and 24% ...19948165242
homologs of the yeast neck filament associated genes: isolation and sequence analysis of candida albicans cdc3 and cdc10.morphogenesis in the yeast saccharomyces cerevisiae consists primarily of bud formation. certain cell division cycle (cdc) genes, cdc3, cdc10, cdc11, cdc12, are known to be involved in events critical to the pattern of bud growth and the completion of cytokinesis. their products are associated with the formation of a ring of neck filaments that forms at the region of the mother cell-bud junction during mitosis. morphogenesis in candida albicans, a major fungal pathogen of humans, consists of bot ...19948152419
identification and characterization of aspergillus nidulans mutants defective in cytokinesis.filamentous fungi undergo cytokinesis by forming crosswalls termed septa. here, we describe the genetic and physiological controls governing septation in aspergillus nidulans. germinating conidia do not form septa until the completion of their third nuclear division. the first septum is invariantly positioned at the basal end of the germ tube. block-and-release experiments of nuclear division with benomyl or hydroxyurea, and analysis of various nuclear division mutants demonstrated that septum f ...19948150280
in vitro binding of the two-finger repressor crea to several consensus and non-consensus sites at the ipna upstream region is context dependent.the two zinc-fingers of the aspergillus nidulans repressor crea recognize the consensus hexanucleotide 5'-syggrg-3'. we have determined all the crea binding sites in a approximately 2 kb region upstream the ipna gene. our analysis shows that (i) crea binds to certain consensus sites in a context-dependent manner; (ii) five non-consensus 6-bp sequences are also recognized by crea; this non-canonical binding correlates with the presence of a second, neighbouring crea binding site, suggesting that ...19948143847
sulfur amino acid metabolism and its regulation in fungi: studies with aspergillus nidulans. 19938140816
the aspergillus nidulans abaa gene encodes a transcriptional activator that acts as a genetic switch to control development.the aspergillus nidulans abaa gene encodes a protein containing an atts dna-binding motif and is required for the terminal stages of conidiophore development. results from gel mobility shift and protection, missing-contact, and interference footprint assays showed that abaa binds to the sequence 5'-cattcy-3', where y is a pyrimidine, making both major- and minor-groove contacts. multiple abaa binding sites are present in the cis-acting regulatory regions of several developmentally controlled str ...19948139553
the alcohol dehydrogenase gene adh1 is induced in aspergillus flavus grown on medium conducive to aflatoxin aspergillus flavus cdna library was screened by differential hybridization to isolate clones corresponding to genes that are actively transcribed under culture conditions conducive to aflatoxin biosynthesis. one clone with a 1.28-kb insert was isolated, and its nucleotide sequence was determined. the nucleotide sequence of this clone had 75% dna identity to those of the alcohol dehydrogenase genes from aspergillus nidulans, and the putative polypeptide translated from the cdna sequence had 82 ...19948135521
cytoplasmic dynein is involved in nuclear migration in aspergillus nidulans.nuclear migration plays an important role in the growth and development of many organisms including the multinuclear fungus aspergillus nidulans. we have identified four genes, nuda, nudc, nudf, and nudg, in which temperature-sensitive mutations affect nuclear distribution. in this report, we describe the cloning of the nuda gene by complementation of the mutant phenotype by using a chromosome viii-specific cosmid library. a genomic fragment of nuda hybridized to an mrna of approximately 14 kb. ...19948134356
at least three genes are responsible for benomyl-resistance in metarhizium anisopliae.four benomyl-resistant mutants isolated from metarhizium anisopliae were 10 to 500 times more resistant than the original mt strain. the resistance markers analysed in three of these mutants were due to three different mutations and no additive effect of these genes was observed in double mutants. the four mutants presented normal conidiation in the presence or absence of benomyl and no sensitivity or resistance to temperature. probably m. anisopliae has a mechanism of benomyl resistance differi ...19948127229
alpha-l-arabinofuranosidase production by aspergillus nidulans.the effects of some physico-chemical parameters on production of extracellular alpha-l-arabinofuranosidase by aspergillus nidulans were examined. highest levels of alpha-l-arabinofuranosidase were generated with cultures grown on 1% (w/v) purified beet pulp arabinan at 30 degrees c and at an initial ph of 7.0. the enzyme was shown to be very sensitive to the action of proteases. zymogram overlay of a protein profile obtained by sds-page revealed the occurrence of a band (m(r) 36,000) exhibiting ...19948125239
regulation of the expression of the isocitrate lyase gene (acud) of aspergillus nidulans.analysis of the promoter region of the acetate-induced isocitrate lyase gene (acud) of aspergillus nidulans is described. transcription start sites were detected at positions -163, -170 and approximately -281 upstream of the atg. transcription analysis showed that the acud gene is transcribed during growth on acetate but not on hexoses or glycerol. expression of the acud gene was studied under inducing and repressing conditions in cre+, crea, creb and crec mutant strains, showing that the crea(d ...19948121406
an 'instant gene bank' method for gene cloning by mutant complementation.we describe a new method of gene cloning by complementation of mutant alleles which obviates the need for construction of a gene library in a plasmid vector in vitro and its amplification in escherichia coli. the method involves simultaneous transformation of mutant strains of the fungus aspergillus nidulans with (i) fragmented chromosomal dna from a donor species and (ii) dna of a plasmid without a selectable marker gene, but with a fungal origin of dna replication ('helper plasmid'). transform ...19948121403
an "instant gene bank" method for heterologous gene cloning: complementation of two aspergillus nidulans mutants with gaeumannomyces graminis dna.we present a novel technique for gene cloning by complementation of mutations in aspergillus nidulans with dna from a heterologous organism, gaeumannomyces graminis. this technique bypasses the time-consuming and difficult construction of gene libraries, making it both rapid and simple. the method relies on recombination between a fungal replicating vector phelp1 and linear g. graminis genomic dna during co-transformation. we were able to complement two out of seven a. nidulans mutants tested an ...19948121400
identification of substrate specificity determinants for the cell cycle-regulated nima protein kinase.nima is a cell cycle-regulated protein kinase required for the g2/m transition in the filamentous fungus aspergillus nidulans. previous biochemical characterization of the recombinant enzyme indicated that nima is a protein serine/threonine specific kinase with beta-casein being the best substrate from the many proteins and peptides tested (lu, k.p., osmani, s.a., and means, a.r. (1993) j. biol. chem. 268, 8769-8776). however, substrate specificity or physiologically relevant substrates for nima ...19948120013
fungal catabolic gene regulation: molecular genetic analysis of the amds gene of aspergillus nidulans.aspergillus nidulans is an excellent experimental organism for the study of gene regulation. genetic and molecular analyses of trans-acting and cis-acting mutations have revealed a complex pattern of regulation involving multiple independent controls. expression of the amds gene is regulated by the facb and amda genes which encode positively acting regulatory proteins mediating a major and a minor form of acetate induction respectively. the product of the amdr gene mediates omega amino acid indu ...19938119589
induction of pseudohyphal growth by overexpression of phd1, a saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.when starved for nitrogen, mata/mat alpha cells of the budding yeast saccharomyces cerevisiae undergo a dimorphic transition to pseudohyphal growth. a visual genetic screen, called phd (pseudohyphal determinant), for s. cerevisiae pseudohyphal growth mutants was developed. the phd screen was used to identify seven s. cerevisiae genes that when overexpressed in mata/mat alpha cells growing on nitrogen starvation medium cause precocious and unusually vigorous pseudohyphal growth. phd1, a gene whos ...19948114741
two novel deduced serine/threonine protein kinases from saccharomyces cerevisiae.we have cloned genes for two closely related protein kinase (pk) homologues from saccharomyces cerevisiae. sequence alignment of the kinase domain with previously characterized pk reveals the highest degree of similarity with second messenger-regulated kinases. rck1 encodes a 58-kda protein, and is weakly expressed. rck2 encodes a 65-kda protein, and transcripts from this gene are readily detected. rck1 has been mapped to the l arm of chromosome vii, and rck2 to chromosome xii. disruption of the ...19948112585
characterisation of the gene encoding acetyl-coa synthetase in penicillium chrysogenum: conservation of intron position in plectomycetes.acetyl-coenzyme a synthetase (acs; ec from some plectomycete fungi is possibly involved in an accessory step of penicillin biosynthesis, in addition to its role in primary metabolism. we present the characterisation of the gene encoding this enzyme in penicillium chrysogenum, which we designated acua. sequencing of genomic and cdna clones showed that the coding region was interrupted by five introns, located at the same positions as those present in the aspergillus nidulans homologue. t ...19938103029
toxin-deficient mutants from a toxin-sensitive transformant of cochliobolus heterostrophus.tox1 is the only genetic element identified which controls production of t-toxin, a linear polyketide involved in the virulence of cochliobolus heterostrophus to its host plant, corn. previous attempts to induce toxin-deficient (tox-) mutants, using conventional mutagenesis and screening procedures, have been unsuccessful. as a strategy to enrich for tox- mutants, we constructed a tox1+ strain that carried the corn t-urf13 gene (which confers t-toxin sensitivity) fused to a fungal mitochondrial ...19948088521
biolistic transformation of conidia of botryotinia fuckeliana.botryotinia fuckeliana, the causal agent of grey mould, was biolistically transformed to hygromycin b resistance using a plasmid (poht) containing a bacterial hygromycin phosphotransferase gene fused to regulatory sequences from aspergillus nidulans. multiple copies of the plasmid, precipitated onto tungsten particles, were delivered into the conidia by a helium-driven gene gun. southern analysis showed that the plasmid was integrated into the fungal genome at one single locus. after five subseq ...19948087880
transformation of trichoderma reesei based on hygromycin b resistance using homologous expression signals.trichoderma reesei was transformed to hygromycin b resistance using a novel vector, which contains the e. coli hygromycin b phosphotransferase gene (hph) fused between promoter and terminator elements of the homologous trichoderma pki1 (coding for pyruvate kinase) and cbh2 (coding for cellobiohydrolase ii) genes, respectively. transformation frequencies of over 1,800--2,500 transformants/micrograms dna were obtained, which is a 15--20-fold increase over that with pan7-1, which contains hph betwe ...19948082210
a new selection method for isolating mutants defective in acetate utilisation in aspergillus nidulans.propionate medium is normally toxic for the growth of aspergillus nidulans. spontaneous mutations relieving the toxicity to propionate, which arose on propionate medium, have been shown to be mutations in acetate metabolism. one acu- mutant is allelic with acua (the structural gene for acetyl-coa synthetase), another with acub (the regulatory gene involved in the induction of enzymes concerned with acetate metabolism, including acetyl-coa synthetase), and a third mutant, acuo, represents a new a ...19948082165
the penicillium chrysogenum and aspergillus nidulans weta developmental regulatory genes are functionally equivalent.aspergillus nidulans and penicillium chrysogenum are related fungi that reproduce asexually by forming multicellular conidiophores and uninucleate conidia. in a. nidulans, spore maturation is controlled by the weta (aweta) regulatory gene. we cloned a homologous gene (pweta) from p. chrysogenum to determine if spore maturation is regulated by a similar mechanism in this species. the pweta and aweta genes are similar in structure and functional organization. the inferred polypeptides share 77% ov ...19948078481
cloning and characterization of the pda6-1 gene encoding a fungal cytochrome p-450 which detoxifies the phytoalexin pisatin from garden pea.the ability to detoxify pisatin, a phytoalexin produced by garden pea (pisum sativum), is controlled by a family of pda (pisatin demethylating ability) genes in the phytopathogenic fungus nectria haematococa, mp (mating population) vi. six known pda genes each encode characteristic levels of inducible enzyme activity and are associated with different degrees of virulence on pea. to elucidate the phenotypic differences associated with these genes, we have cloned and characterized the pda6-1 gene ...19948076822
evolution of transcription-regulating proteins by enzyme recruitment: molecular models for nitrogen metabolite repression and ethanol utilisation in eukaryotes.studies on the quinic acid utilisation gene (qut) cluster in aspergillus nidulans showed that the genes encoding transcriptional activator and repressor proteins evolved by co-opting duplicated copies of genes encoding metabolic enzymes. in order to test the hypothesis that this was a general route for the genesis of regulatory proteins, the origins of the major control protein mediating nitrogen metabolite repression (an example of inter-pathway regulation) and ethanol utilisation (an example o ...19948076813
the aspergillus nidulans crea protein mediates glucose repression of the ethanol regulon at various levels through competition with the alcr-specific transactivator.carbon catabolite repression in aspergillus nidulans is mediated by a negative-acting protein coded by the crea gene. we have investigated how crea controls the expression of the ethanol regulon genes. crea is a major component of the control of this regulon. its presence in the cell results in a permanent, albeit partial, repression of the alc genes under all physiological growth conditions, even when the fungus is grown on carbon sources considered to be non-repressing. a crucial step in the c ...19948076597
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 ...19948070419
hyphal tip extension in aspergillus nidulans requires the mana gene, which encodes phosphomannose isomerase.a strain of aspergillus nidulans carrying a temperature-sensitive mutation in the mana gene produces cell walls depleted of d-mannose and forms hyphal tip balloons at the restrictive temperature (b.p. valentine and b.w. bainbridge, j. gen. microbiol. 109:155-168, 1978). we have isolated and characterized the mana gene and physically located it between 3.5 and 5.5 kb centromere distal of the ribob locus on chromosome viii. the mana gene contains four introns and encodes a 50.6-kda protein which h ...19948065336
regulation of the xylanase-encoding xlna gene of aspergillus tubigensis.a gene encoding an endo-1,4-beta-xylanase from aspergillus tubigensis was cloned by oligonucleotide screening using oligonucleotides derived from amino acid sequence data obtained from the purified protein. the isolated gene was functional as it could be expressed in the very closely related fungus aspergillus niger. the xylanase encoded by this gene is synthesized as a protein of 211 amino acids. after cleavage of the presumed prepropeptide this results in a mature protein of 184 amino acids wi ...19948065265
synechocystis sp. pcc6803 fusb gene, located outside of the str operon, encodes a polypeptide related to protein synthesis factor ef-g.synechocystis sp. pcc6803, a cyanobacterium, possesses an unusual gene (fusb) which encodes a protein with strong homology to protein synthesis elongation factor g (ef-g), although it is not linked to the classical str operon. the fusb gene is redundant, since a synechocystis gene similar to str operon-encoded fusa genes of other bacteria is also present (based on pcr and hybridization results). there is no evidence for the presence of a fusb homologue in other bacteria. the synechocystis fusb g ...19948061323
enhancers of conidiation mutants in aspergillus nidulans.mutants at a number of loci, designated sthenyo, have been isolated as enhancers of the oligoconidial mutations at the meda locus. two loci have been mapped: stha on linkage group i, and sthb on linkage group v. two probable alleles have been identified at each locus but two further mutants were unlinked to either stha or sthb. neither stha nor sthb mutants have conspicuous effects on morphology on their own, nor could the stha1 sthb2 double mutant be distinguished from wild type. mutants at bot ...19948056325
synthesis of sterigmatocystin on a chemically defined medium by species of aspergillus and chaetomium.sterigmatocystin (st) is a secondary metabolite and a principal mycotoxin known to be produced by over 30 species of filamentous fungi. it is also one of the late intermediates in aflatoxin biosynthesis. we have tested the ability of 7 species of aspergillus, including 4 strains of a. versicolor, one species of bipolaris, and two species of chaetomium, to produce st on a sucrose-salts-phenylalanine defined medium as well as on three complex substrates. highest st production in our survey was by ...19948047108
nitrate reductase of the ascomycetous fungus, leptosphaeria maculans: gene sequence and chromosomal location.the nitrate reductase (niad) gene was isolated from the phytopathogenic loculoascomycete leptosphaeria maculans by screening a genomic dna library with the aspergillus nidulans niad gene. the l. maculans niad gene is the first protein-encoding gene characterised from this fungus. it encodes a predicted protein of 893 amino acids and contains four putative introns at positions in the gene equivalent to those of four of the six introns in the a. nidulans niad gene. mutants defective in niad and mo ...19948041355
efficient independent activity of a monomeric, monofunctional dehydroquinate synthase derived from the n-terminus of the pentafunctional arom protein of aspergillus nidulans.the dehydroquinate synthase (dhq synthase) functional domain from the pentafunctional arom protein of aspergillus nidulans has previously been overproduced in escherichia coli [van den hombergh, moore, charles and hawkins (1992) biochem j. 284, 861-867]. we now report the purification of this domain to homogeneity and subsequent characterization. the monofunctional dhq synthase was found to retain efficient catalytic activity when compared with the intact pentafunctional arom protein of neurospo ...19948037684
developmental decisions in aspergillus nidulans are modulated by ras 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 ...19948035812
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.19948030378
analysis of the regulation of the aspergillus nidulans acud gene, encoding isocitrate lyase, by construction of a hybrid 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. ...19948028581
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 ...19948025681
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 ...19948022307
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 ...19948017929
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 ...19948013455
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 ...19948013452
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 ...19948001767
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 ...19948001174
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 ...19947988903
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 ...19947988872
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 ...19947988865
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 ...19947982501
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 ...19947980291
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 ...19947972016
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/ ...19947966201
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 ...19947962194
virulence studies of aspergillus nidulans mutants requiring lysine or p-aminobenzoic acid in invasive pulmonary 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 ...19947960102
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 ...19947959044
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 ...19947957060
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 ...19947954890
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 ...19947945306
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 ...19947937873
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 ...19937935565
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 ...19937934851
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. ...19947929762
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 ...19947929068
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 ...19947927700
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 ...19947927699
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 ...19947926755
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 " ...19947923408
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 ...19947922884
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 ...19947918658
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 ...19937916713
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 ...19947915967
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 ...19947914670
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 ...19947907796
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 ...19957896804
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 ...19957896078
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 ...19957894714
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 ...19957889945
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 ...19957889944
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 ...19957888172
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 ...19957883170
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 ...19957882981
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 ...19947882430
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 ...19957876088
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.19957875577
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 ...19957875309
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 ...19947872840
Displaying items 3401 - 3500 of 5149