Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
development of fluorescent-antibody reagents for demonstration of pseudallescheria boydii in tissues.we prepared fluorescent-antibody reagents to detect and identify pseudallescheria boydii in tissue. antisera to broken mycelium and condidia (particulate antigens) and to culture filtrates (soluble antigens) of p. boydii were produced in rabbits. antisera and globulin fractions of the antisera were labeled with fluorescein isothiocyanate and evaluated for their ability to stain p. boydii in tissues. the conjugates were first tested with cultures of 25 p. boydii isolates and 26 heterologous fungi ...19836195179
high-frequency conversion to a "fluffy" developmental phenotype in aspergillus spp. by 5-azacytidine treatment: evidence for involvement of a single nuclear gene.transient exposure of mycelia from aspergillus niger and aspergillus nidulans to the cytidine analog 5-azacytidine, leading to no more than 0.3 to 0.5% substitution for cytosine by 5-azacytosine in a. nidulans dna, resulted in the conversion of a high fraction of the cell population (more than 20%) to a mitotically and meiotically stable "fluffy" developmental phenotype. the phenotypic variants are characterized by the developmentally timed production of a profuse fluffy network of undifferentia ...19836197627
cloning of aspergillus nidulans ribosomal dna in shotgun experiments using the ek2 vector lambda gtwest.t5-622.ecori fragments of aspergillus nidulans dna were cloned in a shotgun type experiment using the ek2 vector lambda gtwest.t5-622. in situ plaque hybridization was used to screen for hybrid phage particles containing sequences coding for ribosomal rna. four clones selected from the whole gene bank were characterized further. two of them contain sequences homologous to a 3.6 kb fragment of a. nidulans rdna.19836198874
transcription of the rrna gene cluster in aspergillus nidulanss.transcription of rdna in aspergillus nidulans was examined by hybridizing labeled cloned rdna fragments to blots of rna gels. one processing pathway was found.198324173152
mitochondrial four-point crosses in aspergillus nidulans : mapping of a suppressor of a mitochondrially inherited cold-sensitive mutation.four-point mitochondrial crosses were conducted in heterokaryons of aspergillus nidulans. the mutations used were (olia1), conferring resistance to oligomycin, (cama112), conferring resistance to chloramphenicol; (cs-67), conferring cold-sensitivity, and ( sumd16), a suppressor of (cs-67). initially, the crosses were conducted by observing the segregation of extranuclear markers in heterokaryotic sectors emerging from the original point of heterokaryosis. this showed that (cama112), (cs-67) and ...198317246113
molecular cloning and sequence analysis of the cyanobacterial gene for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase.ribulose-1,5-bisphosphate carboxylase/oxygenase consists of large subunits (ls) and small subunits. in plants, the ls is encoded in chloroplast dna and the small subunit, in nuclear dna. in cyanobacteria, both subunits are thought to be encoded in chromosomal dna because of prokaryotes. the gene for the ls of ribulose-1,5-bisphosphate carboxylase/oxygenase from a cyanobacterium, anacystis nidulans 6301, has been cloned in pbr322 and subjected to sequence analysis. the coding region contains 1,41 ...198316593333
the mitochondnal genome of aspergillus nidulans contains reading frames homologous to the human urfs 1 and 4.a 2830-bp segment of the mitochondrial genome of the fungus aspergillus nidulans was sequenced and shown to contain two unidentified reading frames (urfs). these reading frames are 352 and 488 codons in length, and would specify unmodified proteins of mol. wts. 39,000 and 54,000, respectively. the derived amino acid sequences indicate that these genes are equivalent to the human mitochondrial urfs 1 and 4, with 39% amino acid homology for urf1 and 26% for urf4. both urfs were shown by secondary ...198311894959
chilling-susceptibility of the blue-green alga anacystis nidulans: iii. lipid phase of cytoplasmic membrane.the lipid phase of cytoplasmic membrane was studied by freeze-fracture electron microscopy in the chilling-susceptible blue-green alga, anacystis nidulans. at growth temperatures, intramembrane particles were distributed at random in the fracture faces of cytoplasmic membrane, whereas, at chilling temperatures, the fracture faces were composed of particle-free and particle-containing regions. these findings indicate that lipids of the cytoplasmic membrane were in the liquid-crystalline state at ...198216662143
nitrogen metabolite repression in aspergillus nidulans: a farewell to tama?previous work has established that nitrogen metabolite repression in aspergillus nidulans is mediated by the positive acting regulatory gene area. pateman and kinghorn (1977) proposed that the gene tama plays an equally important regulatory role in nitrogen metabolite repression as the result of work with "tama(r)-50," an "allele" leading to inability to utilise nitrogen sources other than ammonium, and "tama(d)-1," an "allele" leading to nitrogen metabolite derepression. both "tama(r)-50" and " ...198224186552
a single mutation leads to loss of glutamine synthetase and relief of ammonium repression in aspergillus.glutamine synthetase activity in the ascomycete fungus aspergillus nidulans is regulated by nitrogen source. the lowest activities are obtained when the fungus is grown on l-glutamine, and the highest activities when grown on l-glutamate + arabinose. glutamine auxotrophs of the fungus have been isolated, and one of these mutant strains, glna-1, has been shown to lack the enzyme glutamine synthetase. the mutation is recessive, and is located on the right arm of chromosome ii. in addition to aboli ...198224186546
domain-wide, locus-specific suppression of nitrogen metabolite repressed mutations in aspergillus nidulans.previous work has shown that loss of function mutations (designated are a(r)) in area, a positive acting regulatory gene mediating nitrogen metabolite repression in aspergillus nidulans, lead to inability to utilise nitrogen sources other than ammonium. this work establishes the existence of a gene designated areb where mutations can suppress area(r) mutations in a locus-specific manner for expression of apparently all of the genes under area control. areb mutations are partially dominant in dip ...198224186375
genetic map of mitochondrial dna in podospora anserina.in order to develop an eukaryotic vector with the podospora plasmid, further characterization is required of the mitochondrial dna into which this plasmid is integrated, a physical map (restriction sites) of the podospora chondriome (size 95 kb) has been completed. as prerequisite for the establishment of a genetic (functional) map, 70% of the chondriome was cloned in e. coli vectors. using mitochondrial genes from saccharomyces cerevisiae, six structural genes were located on the podospora chon ...198224186230
the effect of the synergy between sterigmatocystin and a fungal metabolite on bacillus subtilis. 19826175614
recombinogenic and mutagenic effects of the antitumor antibiotic bleomycin in aspergillus nidulans.bleomycin, an antibiotic and antineoplastic drug that inhibits dna synthesis and causes several types of chromosomal aberration, was found to increase mitotic recombination in aspergillus nidulans. heterozygous prototrophic diploid strains grown on media containing bleomycin produced significant increases of yellow and white sectors compared with controls. further, the increased colour segregants were due to mitotic crossing-over, whereas the non-dis junctional segregants remained at the control ...19826181398
effect of alpha-amanitin and actinomycin d on rna synthesis in the protoplasts of aspergillus nidulans.rna synthesis was studied in protoplasts from aspergillus nidulans, which remained metabolically active for several days under the appropriate conditions. it is concluded, that at certain actinomycin d concentrations the ribosomal rna synthesis can be selectively inhibited. however, alpha-amanitin at concentrations up to 400 micrograms/ml neither influenced the total nor the rna polymerase ii directed rna synthesis. it was possible to discriminate between the rna polymerase i or ii directed rna ...19826186893
l-histidine utilization in aspergillus nidulans.histidase activity rather than uptake of l-histidine is the limiting factor for the utilization of histidine as the sole nitrogen source for aspergillus nidulans. histidine cannot act as the sole carbon source, and evidence is presented indicating that this is attributable to an inability to convert histidine to l-glutamate in vivo. it has been shown that this fungus lacks an active urocanase enzyme and that histidine is quantitatively converted to urocanate, which accumulates in the extracellul ...19826120926
the regulation of nadp-linked isocitrate dehydrogenase in aspergillus nidulans.the regulation of nadp-linked isocitrate dehydrogenase (nadp-idh) has been studied in wild-type and mutant strains of aspergillus nidulans. in the wild-type strain studied, the levels of nadp-idh vary in a similar way to those of acetamidase, acetyl-coa synthase, isocitrate lyase and malate synthase under all growth conditions used. similarly, fac mutants, which are altered in the regulation of these enzymes of acetate utilization, are affected in nadp-idh levels in a parallel fashion, as are cr ...19826123545
international commission for protection against environmental mutagens and carcinogens. committee 2 final report. mutagenesis testing as an approach to carcinogenesis. 19826214712
intron within the large rrna gene of n. crassa mitochondria: a long open reading frame and a consensus sequence possibly important in splicing.we describe the sequence of the 2295 nucleotide long intron and 245 nucleotides of the flanking exon sequences within the large (24s) rrna gene of neurospora crassa mitochondria. the intron contains a long open reading frame, which could correspond to ribosomal protein s5. comparison with the corresponding intron of the large rrna gene of yeast mitochondria reveals a single highly homologous 57 nucleotide long sequence, including the sequence (formula; see text), which is present in virtually al ...19826218884
cell wall degradation in the autolysis of filamentous fungi.a systematic study on autolysis of the cell walls of fungi has been made on neurospora crassa, botrytis cinerea, polystictus versicolor, aspergillus nidulans, schizophyllum commune, aspergillus niger, and mucor mucedo. during autolysis each fungus produces the necessary lytic enzymes for its autodegradation. from autolyzed cultures of each fungus enzymatic precipitates were obtained. the degree of lysis of the cell walls, obtained from non-autolyzed mycelia, was studied by incubating these cell ...19826219290
genetic approaches to the analysis of microbial development. 19826297378
a new approach for molecular cloning in cyanobacteria: cloning of an anacystis nidulans met gene using a tn901-induced mutant.a new strategy for molecular cloning in the cyanobacterium anacystis nidulans r-2 is described. this strategy involved the use of a transposon and was developed for the cloning of a gene encoding methionine biosynthesis. a met::tn901 mutant was isolated. chromosomal dna fragments were cloned in the escherichia coli plasmid vector pacyc184. a recombinant plasmid carrying the inactivated met::tn901 gene was selected after transformation to e. coli. the cloned met::tn901 dna fragment was used as a ...19826298064
a physical map of the ribosomal dna repeat unit of aspergillus nidulans.the ribosomal dna repeat unit of aspergillus nidulans has been cloned in pbr322 and a restriction map constructed. the genes coding for the 17s, 5.8s and 25s rrnas are found in blocks separated by a 1.7 kb spacer region, with the 5.8s rna gene lying between the genes for the two larger rnas. the total length of the repeat unit is 7.7 kb. the 5s rrna is not present in the repeat unit.19826299883
construction of a hybrid plasmid capable of replication in the bacterium escherichia coli and the cyanobacterium anacystis nidulans.a hybrid plasmid was constructed between the 5.3-megadalton plasmid (puh24) of anacystis nidulans r2 and the escherichia coli plasmid pbr322. this was accomplished by adding a transposon to pbr322 and transforming this dna into a. nidulans. one resultant hybrid, pls103, had a molecular weight of 6.8 x 10(6), replicated in both organisms, had unique sites for two restriction endonucleases, conferred ampicillin resistance on both organisms, and could be used as a cloning vector in a. nidulans.19826277870
restriction enzyme analysis of mitochondrial dna of members of the genus aspergillus as an aid in taxonomy.restriction endonuclease patterns of mitochondrial dna from seven species of the genus aspergillus (a. nidulans, a. wentii, a. awamori, a. niger, a. oryzae, a. tamarii and a. echinulatus) have been compared in order to test the phylogenetic relationships between these species. the fraction of restriction fragments common between all pairs of species from this set ranged from 0 to 1. the use of this approach for the taxonomy of the genus aspergillus is discussed. the postulated phylogenetic relat ...19826281364
organization of the ribosomal rna gene cluster in aspergillus nidulans.dna coding for ribosomal rna in aspergillus nidulans was found to consist of a unit 7.8 kb in size which is tandemly repeated in the genome and codes for 5.8s, 18s and 26s rrna. the repeat unit has been cloned, and its restriction map and the location of the individual rrna coding sequences within the unit have been established.19826282710
nucleotide sequence of a region of the mitochondrial genome of aspergillus nidulans including the gene for atpase subunit 6.a 1500 bp fragment of the aspergillus nidulans mitochondrial genome contains genes for arginine and asparagine trnas, an unassigned reading frame, and the structural gene for atpase subunit 6. the trna genes possess 66% nucleotide homology and possibly originated by a relatively recent duplication event. the unassigned reading frame displays a low level of homology with the human urf a6l. the predicted amino acid sequence of the a-nidulans atpase subunit 6 gene is 40% homologous to the yeast pol ...19826285306
cloning and expression in escherichia coli k-12 of the biosynthetic dehydroquinase function of the arom cluster gene from the eucaryote, aspergillus nidulans.a 1.35 md dna hindiii fragment containing part of the arom gene cluster or cluster gene of aspergillus nidulans encoding biosynthetic dehydroquinase (5-dehydroquinate hydrolyase) has been cloned in plasmid pbr322 on the basis of functional expression in escherichia coli. the fungal fragment on pbr322, designated phk29, complements a corresponding e. coli dehydroquinase structural gene (arod) mutation. phk29 contains one bamhi, hpaii, psti, smai, xhoi and surprisingly, one hindiii site since phk2 ...19826287167
nucleotide sequence of aspergillus nidulans mitochondrial genes coding for atpase subunit 6, cytochrome oxidase subunit 3, seven unidentified proteins, four trnas and l-rrna.the complete nucleotide sequence of a 14 kb segment of a. nidulans mtdna reveals a rather compact organization of genes transcribed from the same strand and coding for two functionally known proteins, seven unidentified polypeptides (urfs), 24 trnas and two rrnas. one of the urfs is located in the intron of the l-rrna gene and codes for a basic protein of 410 residues. the other urfs are in spacer regions and code for hydrophobic proteins. urfa is homologous to human urf4, and urfb produces a po ...19826290989
dna sequence of the region adjacent to the oxi1 and oxi2 genes from aspergillus nidulans mitochondrial dna. 19826184922
a cis-dominant mutation in aspergillus nidulans affecting the expression of the amds gene in the presence of mutations in the unlinked gene, amda.a mutant producing very high levels of the acetamidase enzyme encoded by the amds gene has been isolated in a strain containing the amda7 mutation, which itself causes high levels of this enzyme. genetic analysis has shown that this mutation, designated amdi66, is adjacent to the amds gene and is cis-dominant in its effect. the amdi66 mutation has little effect on amds expression when present in strains not containing the amda7 mutation. two other amda mutations investigated also interact with t ...19826759305
meiosis in aspergillus nidulans: another example for lacking synaptonemal complexes in the absence of crossover interference. 19826761318
a near terminal pericentric inversion leads to nitrogen metabolite derepression in aspergillus nidulans.the mutation xprd-1, previously shown to be an allele of the area gene and to lead to nitrogen metabolite derepression in aspergillus nidulans, is shown to be associated with a near terminal pericentric inversion in linkage group iii. the left arm break-point is between the adi and sc genes, and the right arm break-point is between the ornc and area genes but just centromere proximal to area. in crosses of xprd-1 strains to inversion-free strains one class of duplication-deficiency progeny is re ...19826761550
in vitro mutational studies with trifluralin and trifluorotoluene derivatives. 19826763485
clustering of spore-specific genes in aspergillus nidulans.we have investigated the chromosomal organization of genes that are expressed specifically in the asexual spores (conidia) of the ascomycete fungus aspergillus nidulans, using two experimental approaches. in the first, 30 different recombinant clones, containing long nuclear dna inserts and at least one spore-specific gene, were selected randomly. the total number of spore-specific genes present in each clone was then determined by rna blot analysis. in the second approach, several chromosomal r ...19826764535
the isolation of a fungal metabolite which exhibits antimicrobial synergy with sterigmatocystin. 19826802793
urea and thiourea transport in aspergillus nidulans.wild-type aspergillus nidulans has an active transport system specific for urea which concentrates urea at least 50-fold relative to the extracellular concentration. it is substrate concentration dependent, with an apparent km of 3 x 10-(5) m for urea. competition studies and the properties of mutants indicate that thiourea is taken up by the same system as urea. thiourea is toxic at 5mm to wild-type cells of aspergillus nidulans. mutants, designated urea1 to urea16, resistant to thiourea have b ...19826814421
de novo formation of the niad gene directed protomer in the nadph-nitrate reductase of aspergillus nidulans. 19826817753
positive regulation in a eukaryote, a study of the uay gene of aspergillus nidulans: i. characterization of alleles, dominance and complementation studies, and a fine structure map of the uay--oxpa cluster.in this paper we characterize genetically a positive eukaryotic regulatory gene: the uay gene of the ascomycete aspergillus nidulans. several steps in the uptake and degradation of purines are under the control of the uay gene (summarized in scazzocchio and gorton 1977). in the present paper 12 uay-mutations are characterized with respect to their inducibility for adenine deaminase, xanthine dehydrogenase (purine hydroxylase i) and urate oxidase and by the absence of the uric acid-xanthine perme ...19827049832
purification and characterization of the conidial laccase of aspergillus nidulans.conidial laccase of aspergillus nidulans was purified by standard protein purification methods. although the purified material showed a cluster of several protein bands on a nondenaturing gel, each of these protein bands had laccase activity. all bands of activity, however, were absent in a strain carrying a mutation in the structural gene for laccase. concentrated solutions (greater than 1 mg/ml) were bright blue, suggesting that, like other laccases, this enzyme contains copper. the enzyme con ...19827050088
aspergillus nidulans as a test organism for chemical mutagens.in the 3 strains of aspergillus nidulans used, bc reduced survival most and 4hmb least. similar trends were found when the effect on gene conversion was studied in a diploid strain and point mutation was scored in a haploid strain. none of the compounds had any effect on mitotic segregation.19827035880
testing for mitotic crossing over and induced aneuploidy using aspergillus nidulans as part of the ukems test programme. 19827035881
hydrolysis of vegetable oils and triglycerides by thermotolerant and zoopathogenic species of aspergillus from nigerian palm produce.the ability of aspergillus fumigatus fres. and aspergillus nidulans (eidam) wint obtained from nigerian palm produce to degrade vegetable oils and triglycerides and the production and activity of their extracellular lipases were studied. both species readily hydrolysed palm oil and palm kernel oil among others liberating free fatty acids in the process. good growth with mycelia production of both fungi were also recorded on the triglycerides used as sources of carbon at 37 degrees c with the bes ...19827040975
[genetic control of recombination processes in aspergillus nidulans. iv. the effect of uvs mutations on the frequency of spontaneous and nitrosomethylurea-induced intragenic mitotic recombination].effects of three uvs mutations were studied on spontaneous and nitrosomethyl-induced intragenic mitotic segregation in the metha region of the chromosome ii in aspergillus diploids homozygous for uvs and heteroallelic for metha mutation. the reversion frequencies of metha alleles in parent haploid strains were also determined. all the mutations increased the frequency of spontaneous and decreased that of induced intragenic mitotic recombination. the frequency of spontaneous reversions was decrea ...19827047300
ergosterol and lanosterol from aspergillus nidulans.ergosterol was identified as the major free sterol of aspergillus nidulans by thin-layer chromatography, alumina column chromatography, gas-liquid chromatography, high-performance liquid chromatography, uv spectroscopy, proton magnetic resonance spectroscopy and mass spectral analysis. lanosterol, the initial cyclized precursor of ergosterol, was identified as a minor component of the free sterols. in the steryl ester material, however, lanosterol was usually more abundant than ergosterol, sugge ...19827050295
a possible regulatory gene for the molybdenum-containing cofactor in aspergillus nidulans.aspergillus nidulans has three molybdoenzymes, nitrate reductase, purine hydroxylase i and purine hydroxylase ii. these three enzymes share a molybdenum-containing cofactor whose synthesis requires the integrity of five loci, designated cnxabc, cnxe, cnxf, cnxg and cnxh. here we report the existence of a sixth locus, designated cnxj, which might be involved inthe regulation of cofactor levels. when grown in the presence, but not in the absence, of tungstate or methylammonium, strains carrying cn ...19827050297
evaluation of 2 different genetic markers for the detection of frameshift and missense mutagens in a. nidulans.21 chemicals, known to induce missense and/or frameshift mutations directly, were assayed for their ability to forward mutate a haploid strain of a. nidulans. 2 genetic markers for forward mutations were used, namely 8-azaguanine resistance and induction of meth a1 suppressors. missense mutagens were usually active when tested with the plate-incorporation technique, whereas frameshift agents were ineffective; some of these, on the other hand, turned out to be positive when tested with a liquid-t ...19826750392
modification of chromosome instability in aspergillus nidulans.strains of aspergillus nidulans with a chromosome segment in duplicate show instability at mitosis; their colonies produce faster-growing sectors which arise from nuclei with spontaneous deletions in either duplicate segment. in an attempt to probe the deletion process, the effects of mutations causing sensitivity to uv treatment, and those of manganous ions, have been studied in strains carrying either dp(i,ii) or dp(iii,viii). for comparison, the effects of mn2+ on balanced and unbalanced dipl ...19826763939
the genetic toxicology in fungi of 4-chloromethylbiphenyl (4cmb), 4-hydroxymethylbiphenyl (4hmb) and benzyl chloride (bc). survey of the results of the u.k.e.m.s. collaborative genotoxicity trial 1981. 19826460178
extracellular siderophores of rapidly growing aspergillus nidulans and penicillium chrysogenum.the highly active extracellular siderophores previously detected in young cultures of aspergillus nidulans and penicillium chrysogenum have been identified as the cyclic ester fusigen (fusarinine c), and its open-chain form, fusigen b (fusarinine b).19826461636
studies on air-borne fungi at qena. iii. thermophilic fungi. 19826759940
temperature-shift analysis of conidial development in aspergillus nidulans. 19826813166
two-way selection of mutants and revertants to chloroneb resistance in aspergillus nidulans.5 mutants of aspergillus nidulans, selected for resistance to chloroneb, were also partially dependent on it. the resistance of these mutants to chloroneb was about 20-150 times higher than that of the original strain. the resistance marker was due to a mutation in a single gene, located in linkage group iii, and behaved as a recessive character. this genetic marker was distal in relation to galal with a recombination frequency of about 30-35%. the different levels of resistance were attributed ...19826750388
growth characteristics of aspergillus nidulans mutans defective in carbohydrate metabolism.several mutants aspergillus nidulans defective in carbohydrate metabolism were tested for growth on different carbon sources. d-galacturonate was found to be a substrate, useful to discriminate between mutants in pyruvate kinase, pyruvate dehydrogenase complex or pyruvate carboxylase. the results of these tests indicate how particular classes of mutants can be obtained and which substrates can be used preferentially for a rapid phenotypical screening of unknown mutants.19826751221
isoelectric focusing and two-dimensional analysis of purified nitrate reductase from aspergillus nidulans.the assimilatory nadph-nitrate oxidoreductase (ec 1.6.6.3) from aspergillus nidulans was purified by means of affinity chromatography and analyzed by agarose isoelectric focusing and two-dimensional electrophoresis. nadph-nitrate reductase activity was not activated by oxidation with potassium ferricyanide and was irreversibly inhibited by acrylamide. electrophoresis of nitrate reductase in 7% polyacrylamide gels resulted in rapid loss of enzyme activity. isoelectric focusing of purified enzyme ...19826751405
mitochondrial l-rrna from aspergillus nidulans: potential secondary structure and evolution.the alignment of gene sequences coding for a. nidulans mitochondrial l-rrna and e. coli 23s rrna indicates a strong conservation of primary and potential secondary structure of both rrna molecules, except that homologies to the 5'-terminal 5.8s-like region and the 3'-terminal 4.5s-like region of bacterial rrna are not detectable on mtdna. the structural organization of the a. nidulans mt l-rrna gene corresponds to that of yeast omega + strains: both genes are interrupted by a large intron sequen ...19826752884
the regulation of urease activity in aspergillus nidulans.aspergillus nidulans can utilize urea as a sole source of nitrogen but not as a carbon source. urea is degraded by a urease. mutation at any one of three genes, ureb, urec, and ured, may result in deficient urease activity. the ureb gene is closely linked to urea, the structural gene for the urea transport protein. the heat lability of ureb- revertant strain, intragenic complementation tests, and the linkage of ureb to urea suggest that ureb is the urease structural gene. the ured gene is probab ...19826753831
internal structure of a mitochondrial intron of aspergillus nidulans.the intron of the mitochondrial apocytochrome b gene, coba, of aspergillus nidulans has been subjected to sequence analysis. it contains an open reading frame of 957 base pairs contiguous with the preceding exon. regions of the translated open reading frames of coba and the third intron of the cob gene in yeast show high amino acid homology. comparison of the coba intron with this and other yeast introns indicates that coba codes for a maturase protein that splices out the intron encoding it and ...19826755468
making ends meet: a model for rna splicing in fungal mitochondria.on the basis of available nucleotide sequence and genetic data; we present a model for rna splicing in fungal mitochondria. seven intron rnas of two fungal species can form identical secondary structures, involving four conserved sequences, which bring the ends of each intron together and allow an internal guide rna sequence to pair with exon bases adjacent to the splice junctions. the splicing sites are thus aligned precisely within a conserved structure, which we suggest could present specific ...19826757759
purification and characterization of the assimilatory nadph-nitrate reductase of aspergillus nidulans.nadph-nitrate reductase [nadph : nitrate oxidoreductase, ec 1.6.6.3] was purified 500-fold from aspergillus nidulans with an overall yield of about 20%. the purified enzyme catalyzed nadph-nitrate, nadph-cytochrome c, fadh2-nitrate and reduced methyl viologen-nitrate reductase activities. its molecular weight was estimated to be 180,000 from the stokes radius and sedimentation coefficient. the oxidized enzyme exhibited an absorption spectrum having a peak at 412 nm and a broad shoulder at about ...19827042701
polyamine transport in aspergillus nidulans.the uptake of putrescine, spermidine and spermine was studied in aspergillus nidulans using 14c-labelled polyamines. active transport systems, inhibited by azide and regulated by nitrogen availability, exist at least for putrescine and spermidine. putrescine is taken up two to three times more rapidly than spermidine, reflecting a lower km for the former substrate. the two uptake systems appear to be independent, spermidine uptake being inhibited by both putrescine and spermine, while putrescine ...19827042908
genetical and biochemical aspects of quinate breakdown in the filamentous fungus aspergillus nidulans.in the ascomycetous fungus aspergillus nidulans, the expression of two inducible, contiguous or closely linked genes (qutb and qutc) which encode enzymes for quinate breakdown to protocatechuate, appears to be controlled by the product of a tightly linked third genet (quta). the qut gene cluster locates on chromosome viii. the catalytic steps required for this conversion are dehydrogenase, dehydroquinase, and dehydratase, and these activities are induced by the presence of quinate in a similar m ...19827049157
molecular and genetic methods for studying mitosis and spindle proteins in aspergillus nidulans. 19827050618
metabolism of 5'-methylthioadenosine in aspergillus nidulans. an alternative pathway for methionine synthesis via utilization of the nucleoside methylthio group.experiments in which 5'-methylthioadenosine was used as a culture supplement for methionine-requiring mutants of aspergillus nidulans with various enzymatic lesions indicated that the methylthio group derived from the nucleoside can be recycled to methionine. the results strongly suggest that methionine may be synthesized in the reaction catalyzed by homocysteine synthase (ec 4.2.99.10) in which o-acetylhomoserine is an acceptor of the methylthio group. the first step on the salvage pathway of t ...19827052140
mitotic aneuploidy induced by sodium deoxycholate in aspergillus nidulans.sodium deoxycholate is shown to induce aneuploidy in a heterozygous diploid strain of aspergillus nidulans. it is suggested that this is the result of interference with the normal functioning of the mitotic apparatus through disruption of the nuclear membrane. this effect limits the value of sodium deoxycholate as a paramorphogenic agent in the estimation of the genotoxic effects of environmental and genetic factors.19827038466
aspergillus nidulans: systems and results of tests for chemical induction of mitotic segregation and mutation. i. diploid and duplication assay systems. a report of the u.s. epa gene-tox program. 19827038472
aspergillus nidulans: systems and results of tests for induction of mitotic segregation and mutation. ii. haploid assay systems and overall response of all systems. a report of the u.s. epa gene-tox program. 19827038473
selection for increased penicillin titre following hybridization of divergent lines of aspergillus nidulans.sexual hybridization of two divergent lines of aspergillus nidulans, which had been selected for increased penicillin titre through successive cycles of mutagenesis, released considerable variation for this character. the recovery of segregants with titres equivalent to that of the unselected ancestor suggested that mutations in different genes had been selected in the two lines. however, complementary segregants with substantially improved titres were not found, indicating interactions, probabl ...19817040598
induction of fenarimol-efflux activity in aspergillus nidulans by fungicides inhibiting sterol biosynthesis.fungicides inhibiting sterol biosynthesis belong to chemically distinct classes such as imidazole, morpholine, pyridine, pyrimidine and triazole derivatives. incubation of mycelium of aspergillus nidulans for 90 min with representatives of these fungicides induced an efflux activity which prevented accumulation of fenarimol, a pyrimidine derivative, into the mycelium. induction of this efflux activity reduced the fungitoxicity of fenarimol. addition of oligomycin to mycelium in which fenarimol-e ...19817040601
biochemical analysis of mutants defective in nitrate assimilation in neurospora crassa: evidence for autogenous control by nitrate reductase.a biochemical analysis of mutants altered for nitrate assimilation in neurospora crassa is described. mutant alleles at each of the nine nit (nitrate-nonutilizing) loci were assayed for nitrite reductase activity, for three partial activities of nitrate reductase, and for nitrite reductase activity. in each case, the enzyme deficiency was consistent with data obtained from growth tests and complementation tests in previous studies. the mutant strains at these nit loci were also examined for alte ...19816460156
solubility of (1 leads to 3)-beta-d/(1 leads to 6)-beta-d-glucan in fungal walls: importance of presumed linkage between glucan and chitin.in saccharomyces cerevisiae, neurospora crassa, aspergillus nidulans and coprinus cinereus most of the alkali-insoluble (1 leads to 3)-beta-d/(1 leads to 6)-beta-d-glucan of the wall can be extracted with dimethyl sulphoxide. the same fraction, and in saccharomyces cerevisiae a small additional fraction, can be extracted by a destructive procedure involving 40% naoh at 100 degrees c. the small fraction of the glucan which resists this treatment becomes soluble after a subsequent treatment with h ...19816460846
regulation of nitrate reductase levels in the cyanobacteria anacystis nidulans, anabaena sp. strain 7119, and nostoc sp. strain 6719.the effect of the nitrogen source on the cellular activity of ferredoxin-nitrate reductase in different cyanobacteria was examined. in the unicellular species anacystis nidulans, nitrate reductase was repressed in the presence of ammonium but de novo enzyme synthesis took place in media containing either nitrate or not nitrogen source, indicating that nitrate was not required as an obligate inducer. nitrate reductase in a. nidulans was freed from ammonium repression by l-methionine-d,l-sulfoximi ...19816780511
nucleotide sequence of 5s ribosomal rna from aspergillus nidulans and neurospora crassa.the nucleotide sequences of 5s rrna molecules isolated from the cytosol and the mitochondria of the ascomycetes a. nidulans and n. crassa were determined by partial chemical cleavage of 3'-terminally labelled rna. the sequence identity of the cytosolic and mitochondrial rna preparations confirms the absence of mitochondrion-specific 5s rrna in these fungi. the sequences of the two organisms differ in 35 positions, and each sequence differs from yeast 5s rrna in 44 positions. both molecules conta ...19816453331
microbial short-term assays with thiram in vitro.the fungicide thiram was assayed in the following tests in vitro, with and without metabolic activation: (1) prophage lambda induction of escherichia coli k12; (2) repair test in salmonella typhimurium (strains ta1538 and ta1978); (3) induction of gene mutations in aspergillus nidulans (metha1 suppressor induction). thiram was positive in the repair test and in the a. nidulans forward-mutation test (4-6 fold increase) in the absence of metabolic activation. a slight increase was observed in prop ...19816454074
adenosine triphosphatase of aspergillus nidulans: variation of ca2+-atpase isoenzymes. 19816456218
cellular and extracellular siderophores of aspergillus nidulans and penicillium chrysogenum.aspergillus nidulans and penicillium chrysogenum produce specific cellular siderophores in addition to the well-known siderophores of the culture medium. since this was found previously in neurospora crassa, it is probably generally true for filamentous ascomycetes. the cellular siderophore of a. nidulans is ferricrocin; that of p. chrysogenum is ferrichrome. a. nidulans also contains triacetylfusigen, a siderophore without apparent biological activity. conidia of both species lose siderophores ...19816242827
atpase activity in gal mutants of aspergillus nidulans. 19816458561
dominant spore color mutants of aspergillus nidulans defective in germination and sexual development.the ascomycete aspergillus nidulans produces green conidia (asexual spores). recessive mutants which produce yellow conidia have been previously isolated from haploid strains and have been shown to be deficient in laccase (diphenol oxidase), an enzyme that requires copper for activity. using a diploid parent strain, we isolated dominant yellow conidial mutants which, in the haploid state, produced even less laccase activity than a recessive mutant. three isolates of such mutants behaved similarl ...19817028722
rna synthesis during the germination of conidia of aspergillus nidulans.rna accumulates most rapidly in germinating conidia of aspergillus nidulans between 6 h and 14 h after the initiation of germination. 3h-adenine is incorporated into all classes of rna before the emergence of the germ tube, but most of the label appears in rrna. there is an increase in total rna polymerase activity, which occurs in parallel with the increase in rna synthesis. three peaks of rna polymerase activity were separated on phosphocellulose columns and their properties investigated.19817031437
sensitive detection of tritium in southern blot and plaque hybridizations. 19817032353
mutagenicity of methyl benzimidazole-2-yl carbamate (mbc) towards aspergillus nidulans (eidam) winter and cladosporium cucumerinum ellis & arth.the ability of methyl benzimidazol-2-yl carbamate (mbc) to induce point mutations to carboxin and mbc resistance was tested in aspergillus nidulans (eidam) winter and cladosporium cucumerinum ellis & arth. a sub-lethal concentration (e.d.50) of mbc, when incorporated into a complete agar medium, induced mbc resistance in germinating conidia of a. nidulans and carboxin resistance in germinating conidia of c. cucumerinum. the significance of these findings in relation to fungicide resistance in th ...19817010147
the ph dependence of the mutagenicity of methyl benzimidazol-2-yl carbamate (mbc) towards aspergillus nidulans (eidam) winter and cladosporium cucumerinum ellis & arth.the ability of methyl benzimidazol-2-yl carbamate (mbc) to induce point mutations to carboxin and mbc resistance in aspergillus nidulans (eidam) winter and cladosporium cucumerinum ellis & arth. was dependent upon the ph value of the agar medium into which it had been incorporated. the relevance of this in relation to testing chemicals for a possible mutagenic activity with microorganisms is discussed.19817010148
isolation of protoplasts from aspergillus nidulans conidiospores.protoplasts were prepared from conidiospores of aspergillus nidulans. the mononucleated conidia gave protoplasts of a uniform size, approximately 5-micron diameter, depending on the strain and the stabilizing medium used. conidia were preincubated with 2-deoxy-d-glucose in a minimal medium at 37 degrees c for 3 h. the swollen conidia were collected, resuspended in a buffer containing 0.4 m (nh4)2so4 as stabilizer, and incubated with oerskovia lytic enzymes at 30 degrees c for 3 or 4 h. approxima ...19817016284
naturally occurring diploid isolates of aspergillus nidulans.six wild isolates belonging to heterokaryon compatibility group a of the birmingham aspergillus nidulans collection were shown to be diploid. five were proven heterozygous for a naturally occurring conditional lethal haploid genotype. it is considered unlikely that these diploids arose by mutation in storage. consequently, somatic diploidy is a regular occurrence in the natural population of this saprophytic species.19817033446
mutagenicity of monoadducts and cross-links induced in aspergillus nidulans by 8-methoxypsoralen plus 365 nm radiation. 19817027284
mutagenicity of chemicals of industry and agricultural relevance in salmonella, streptomyces and aspergillus. 19817026896
growth-mediated metabolic activation of promutagens in aspergillus nidulans.7 procarcinogens belonging to different chemical classes (nitrosamines, hydrazoalkanes, oxazaphosphorines and aromatic amines) were tested in a. nidulans for the induction of point mutations with two genetic systems (8-ag resistance and induction of methionine suppressors). dimethylnitrosamine, diethylnitrosamine, nitrosomorpholine, dimethylhydrazine, procarbazine and cyclophosphamide gave positive results with a good dose--effect relationship in the growth-mediated assay, whereas they gave nega ...19817010140
a method for the selection of deletion mutations in the l-proline catabolism gene cluster of aspergillus nidulans. 19817035292
induced gene mutation and mitotic non-disjunction in a. nidulans.toxicants of different classes were analysed for capacity to induce gene mutation and mitotic non-disjunction in aspergillus nidulans, using selective and permissive tests, respectively. ethanol, amphotericin b and micanozole, all affecting membrane integrity, induced only non-disjunction, emphasizing the röle of the membrane in mitosis. benomyl and isopropyl-3-chlorophenyl carbamate (cipc), two pesticides which interfere with spindle system, induced only non-disjunction. conversely, mitomycin c ...19817036415
positive regulation in a eukaryote, a study of the uay gene of aspergillus nidulans. ii. identification of the effector binding protein.in this publication we report the identification of a protein likely to be coded by uay, a regulatory gene in the ascomycete aspergillus nidulans. uay is a positive control gene necessary for the expression of at least eight unlinked structural genes involved in purine uptake and degradation (scazzocchio and gorton 1977). the physiological effector of the uay system is uric acid, while some of its thioanalogs serve as gratuitous inducers. effector binding proteins were detected by binding to 2-t ...19817012545
the regulation of phosphoenolpyruvate carboxykinase and the nadp-linked malic enzyme in aspergillus nidulans.it has previously been suggested that the synthesis of phosphoenolpyruvate carboxykinase (ec 4.1.1.32) in aspergillus nidulans is regulated by a repression-derepression mechanism involving a glycolytic intermediate, and not by induction. results obtained using compounds that enter the tricarboxylic acid cycle via 2-oxoglutarate, and that can supply both a carbon and a nitrogen source for a. nidulans, suggest it is more likely that the synthesis of phosphoenolpyruvate carboxykinase is inducible, ...19817033461
mitotic processes which restore genome balance in aspergillus nidulans.previous work had shown that haploid strains of aspergillus nidulans with a duplicate chromosome segment (one in normal position, one translocated to another chromosome) were unstable at mitosis; genome balance was restored by spontaneous deletion of either duplicate segment. diploids with an extra, translocated segment showed high instability which was confined to the excess segments; loss of one of these, usually that in translocated position, gave balanced diploid nuclei and the loss was assu ...19817033469
[otomycosis in the south of chile]. 19817034110
organization of a gene cluster expressed specifically in the asexual spores of a. nidulans.we have investigated the organization and regulation of a 13.3 kb region of the aspergillus nidulans genome that is preferentially expressed during conidiophore development. this cloned dna segment codes for six polysomal poly(a)rnas present in dormant asexual spores (conidia) at from 8 to 50 copies per cell. the genes encoding these rnas occur once per haploid genome, are separate and distinct, appear to be colinear with their mature rna products and are present in both polarities. two of the g ...19817034956
splice points of the third intron in the yeast mitochondrial cytochrome b gene.we report the nucleotide sequences at the splicing junctions of intron 13 of the cytochrome b (box) "long" gene of the mitochondrion of saccharomyces cerevisiae and compare them with the homologous sequences in aspergillus nidulans. the two introns occupy exactly the same position and display an open reading frame in phase with the preceding exon at the 5' end and a blocked region at the 3' end.19817034963
a third unlinked gene controlling the pyruvate dehydrogenase complex in aspergillus nidulans.pyruvate dehydrogenase complex mutants of aspergillus nidulans were obtained by ultraviolet treatment and enrichment procedures. among 160 glycolytic mutants, 86 pyruvate dehydrogenase complex mutants (including some temperature-sensitive mutants) were found. in addition to genes pdha and pdhb, which are described in previous studies, a third gene, pdhc, controlling the function of the enzyme complex, was identified. the three genes were not linked and were mapped in the following linkage groups ...19817028719
the microbiology of spent mushroom compost and its dust.microorganisms in spent steamed mushroom compost and its dust were enumerated, and identified. some phase ii (indoor composting) compost samples were also examined. steaming of spent compost resulted in a 70-76% reduction in microbial numbers. total counts made with compost fusion agar were approximately two logs greater than those for nutrient agar. the most common bacterial isolate was bacillus licheniformis. the most common actinomycete isolates were streptomyces diastaticus and thermoactinom ...19817197578
growth characteristics of saccharomyces cerevisiae and aspergillus nidulans when biotin is replaced by aspartic and fatty acids.when either aerobic or anaerobic cultures of saccharomyces cerevisiae were supplemented with aspartic and fatty acids in place of biotin, stationary phase populations were very small compared with those obtained in the presence of biotin. similarly, these acids failed to fulfil the role of biotin-requiring strain of aspergillus nidulans. furthermore, a requirement for saturated fatty acid was found with anaerobically cultured s. cerevisiae. cells were fragmented when biotin was replaced by aspar ...19817033444
the mosaic organization of the apocytochrome b gene of aspergillus nidulans revealed by dna sequencing.the coding section of the apocytochrome b gene (coba) of the mitochondrial dna of aspergillus nidulans has been completely sequenced. the gene comprises two exons of 507 and 654 bp separated by one intron of approximately 1.1 kb. the derived amino acid sequence shows 61% homology with that of saccharomyces cerevisiae and 51% homology with the cognate human sequence. comparison of these sequences indicates that uga codes for tryptophan in the a. nidulans mitochondrial system. the intron is in exa ...19817034966
thiram-induced abnormal chromosome segregation in aspergillus nidulans. 19817027033
Refresh
firstprev
...41424344454647484950...
nextlast
Displaying items 4301 - 4400 of 5149