antisuppressor mutations reduce misreading of the genetic code in aspergillus nidulans.antisuppressor mutations were isolated in a strain containing the omnipotent suppressor suac109. the antisuppressors reduce the activity of translational suppressors in vivo and counteract most aspects of the pleiotropic phenotype associated with the suac and the suaa suppressor mutations. using an homologous system for cell-free translation, we have measured translational accuracy in two antisuppressor strains with the genotype suac109 and either the asub11 or the asud14 antisuppressor mutation ...19911878998
characterization of interspecific hybrids within the aspergillus nidulans group by isoenzyme analysis.a comparison of interspecific hybrids within the aspergillus nidulans species group was made by isoenzyme analysis. the gel electrophoretic patterns of the parental species were distinct for most of the enzymes tested. the hybrids were distinguishable from their parents by isoenzyme patterns. the appearance of novel bands in all the interspecific hybrids indicated that nuclear fusion could have occurred. in most hybrids the appearance of the parental bands showed nonpreferential, partial chromos ...19911878817
unusual metabolism of the yeast actin amino this paper we have examined the post-translational modifications of the nh2 terminus of actin from the yeast saccharomyces cerevisiae. like actins examined previously, this actin contains an acetylated nh2 terminus. actins in other organisms undergo a unique post-translational processing event in which the initial amino acid(s) are removed by an actin-specific processing enzyme in an acetylation-dependent reaction. this is defined as actin processing. in yeast, actin retains its initiator met ...19911885608
genetic transformation of auxotrophic mutants of the filamentous yeast trichosporon cutaneum using homologous and heterologous marker genes.a transformation system for the filamentous yeast trichosporon cutaneum based on auxotrophic markers is presented and techniques for the induction, isolation and characterization of mutants are described. a number of auxotrophic mutants were isolated and characterized by using biosynthetic precursors and/or inhibitors. a mutant unable to grow in the presence of ornithine could be complemented successfully by spheroplast transformation experiments using the cloned aspergillus nidulans ornithine t ...19911897316
identification of a telomeric fragment from the right arm of chromosome iii of aspergillus nidulans.a minimum of 11 bands hybridising to an oligonucleotide complementary to the putative telomeric repeat sequence (ttaggg)n was visible in a southern blot of ecori-digested aspergillus nidulans genomic dna. all 11 were sensitive to bal 31 exonuclease digestion, consistent with telomeric locations. blots of dna from aneuploid strains deleted for a dispensable, extreme distal region on the right arm of chromosome iii lack a 1.3-kb ecori band, indicating that this fragment is located at or near the c ...19911884987
mutations in the small subunit of cyanobacterial ribulose-bisphosphate carboxylase/oxygenase that modulate interactions with large the cyanobacterium anacystis nidulans (synechococcus pcc6301), ribulose 1,5-bisphosphate carboxylase/oxygenase (rbu-p2 carboxylase) is composed of eight large subunits and eight small subunits. there are three regions of the small subunit that contain amino acids that are conserved throughout evolution, from bacteria to higher plants. since the function of the small subunit is not fully understood, site-directed mutagenesis was performed on highly conserved residues in the first and second co ...19911902220
gamma-tubulin is present in drosophila melanogaster and homo sapiens and is associated with the centrosome.the mipa gene of a. nidulans encodes a newly discovered member of the tubulin superfamily of proteins, gamma-tubulin. in a. nidulans, gamma-tubulin is essential for nuclear division and microtubule assembly and is associated with the spindle pole body, the fungal microtubule organizing center. by low stringency hybridizations we have cloned cdnas from d. melanogaster and h. sapiens, the predicted products of which share more than 66% amino acid identity with a. nidulans gamma-tubulin. gamma-tubu ...19911904010
isolation and characterisation of nuv11, a mutation affecting meiotic and mitotic recombination in aspergillus nidulans.a mutant of aspergillus nidulans, designated nuv11, has been isolated as hypersensitive to the monofunctional alkylating agent mnng and the quasi-uv-mimetic mutagen 4-nqo. the mutation was recessive, resulting from mutation of a single gene which mapped to chromosome iv, and was non-allelic to the previously characterised repair-deficient mutations uvsb and uvsh which are also located on this linkage group. the nuv11 mutation results in slow growth, deficient intragenic and intergenic meiotic re ...19911909187
molecular organisation of the malate synthase genes of aspergillus nidulans and neurospora crassa.the sequencing and comparison of the genes encoding the glyoxylate bypass enzyme malate synthase of aspergillus nidulans (acue) and neurospora crassa (acu-9) are presented. the predicted amino acid sequences of the a. nidulans and n. crassa enzymes are 538 and 542 residues respectively and the proteins are 87% homologous. in fungi, the malate synthase proteins are located in glyoxysomes and the deduced acue and acu-9 proteins both contain a c-terminal s-k-l sequence, which has been implicated in ...19911832736
polyethylene glycol-induced internalization of bacteria into fungal protoplasts: electron microscopic study and optimization of experimental conditions.we studied the mechanism of internalization of escherichia coli into saccharomyces cerevisiae induced by polyethylene glycol (peg) and optimized the experimental conditions. transmission electron microscope studies revealed that the principal factor involved in the internalization was the degree of cell aggregation attained. internalization occurred mainly by an endocytosis-like mechanism and took place during the elimination of peg. the optimum conditions were to treat a mixed pellet of both mi ...19911854204
isolation and developmentally regulated expression of an aspergillus nidulans phenol oxidase-encoding gene, ivob.ivory (ivo) mutants of aspergillus nidulans lack conidiophore pigmentation. we have cloned ivob which codes for a conidiophore-specific phenol oxidase (ahtase) via the adjacent selectable ured gene. gene-library transformants of a ured4 strain proved defective for the vector, but we recovered both ured and ivob from a lambda library of transformant dna. the ivob transcription unit was localized to a sali-xbai 3-kb fragment and its 5' end was located by hybridization with an oligodeoxyribonucleot ...19911901560
structure and evolution of 5s rrna genes and pseudogenes in the genus aspergillus.we have cloned and determined the nucleotide sequence of 18 dna fragments hybridizing to 5s rrna from two aspergillus species--a. wentii and a. awamori. four of the analyzed sequences were pseudogenes. the gene sequences of these two species were very similar and differed from aspergillus nidulans at both constant and microheterogeneous sites.19911920453
pulsed field gel electrophoresis reveals chromosome length differences between strains of cladosporium fulvum (syn. fulvia fulva).methods are described for the electrophoretic separation of chromosome-sized dna molecules from the fungal tomato pathogen cladosporium fulvum (syn. fulvia fulva). using a hexagonal electrode array and switching times of 75 min at 45 v for 14 days, nine bands could be resolved. by comparison with co-electrophoresed aspergillus nidulans chromosomal dna (which was resolved into seven bands), the sizes of the c. fulvum bands are estimated to be between 1.9 mb and 5.4 mb. the two largest bands are b ...19911921976
analysis of the crea gene, a regulator of carbon catabolite repression in aspergillus nidulans.the complete nucleotide sequence derived from a genomic clone and two cdna clones of the crea gene of aspergillus nidulans is presented. the gene contains no introns. the derived polypeptide of 415 amino acids contains two zinc fingers of the c2h2 class, frequent s(t)pxx motifs, and an alanine-rich region indicative of a dna-binding repressor protein. the amino acid sequence of the zinc finger region has 84% similarity to the zinc finger region of mig1, a protein involved in carbon catabolite re ...19911922072
nira, the pathway-specific regulatory gene of nitrate assimilation in aspergillus nidulans, encodes a putative gal4-type zinc finger protein and contains four introns in highly conserved regions.the nucleotide sequence of nira, mediating nitrate induction in aspergillus nidulans, has been determined. alignment of the cdna and the genomic dna sequence indicates that the gene contains four introns and encodes a protein of 892 amino acids. the deduced nira protein displays all characteristics of a transcriptional activator. a putative double-stranded dna-binding domain in the amino-terminal part comprises six cysteine residues, characteristic for the gal4 family of zinc finger proteins. an ...19911922075
genome analysis of imperfect fungi: electrophoretic karyotyping and characterization of the nuclear gene coding for glyceraldehyde-3-phosphate dehydrogenase (gpd) of curvularia lunata.the gene coding for glyceraldehyde-3-phosphate dehydrogenase (gpd) has been isolated from a genomic library of the filamentous fungus curvularia lunata. the coding region of this gene consists of 1014 nucleotides and is interrupted by four introns. the gpd gene product shows a high degree of sequence identity with the corresponding proteins of various species belonging to both taxonomically related (e.g., aspergillus nidulans), as well as more divergent, taxa. using contour-clamped homogeneous e ...19911934112
hygromycin- and paromomycin-resistant mutants of aspergillus nidulans alter translational fidelity.mutants of aspergillus nidulans resistant to the aminoglycoside antibiotics paromomycin and hygromycin b have been isolated and their growth characteristics are described here. most paromomycin mutants were cross-resistant to hygromycin and geneticin. all the hygromycin-resistant mutants were slightly cross-resistant to geneticin. out of the 15 mutants tested 14 had drug-resistant ribosomes in vitro and all 12 of those investigated further had reduced levels of translational misreading. five new ...19911934127
cloning, sequencing and expression of the schwanniomyces occidentalis nadp-dependent glutamate dehydrogenase gene.the cloned nadp-specific glutamate dehydrogenase (gdh) genes of aspergillus nidulans (gdha) and neurospora crassa (am) have been shown to hybridize under reduced stringency conditions to genomic sequences of the yeast schwanniomyces occidentalis. using 5' and 3' gene-specific probes, a unique 5.1 kb bcli restriction fragment that encompasses the entire schwanniomyces sequence has been identified. a recombinant clone bearing the unique bcli fragment has been isolated from a pool of enriched clone ...19911934128
structure of the aspergillus niger pela gene and its expression in aspergillus niger and aspergillus nidulans.aspergillus niger pectin lyases are encoded by a multigene family. the complete nucleotide sequence of the pectin lyase pla-encoding gene pela has been determined. comparison of the deduced amino acid sequence with the deduced amino acid sequence of the other characterized pectin lyase, pld, shows that the proteins share 69% amino acid identity. when grown on media with pectin as the sole carbon source, a. niger transformants containing multiple copies of the pela gene show raised mrna levels an ...19911934134
transformation of aspergillus terreus with the hygromycin b resistance marker from escherichia coli.aspergillus terreus was transformed to hygromycin b resistance using a bacterial resistance gene under the control of aspergillus nidulans regulatory sequences. southern hybridization of transformants indicated that in most of the cases the vector dna was integrated into the recipient chromosome in the form of tandem arrays. transformants were mitotically stable in both selective and non-selective medium and retained their capacity to produce xylanase or glucoamylase activities.19911936947
the tubb alpha-tubulin gene is essential for sexual development in aspergillus nidulans.the filamentous fungus aspergillus nidulans has two genes encoding alpha-tubulin, tuba and tubb. mutational analysis of tuba has demonstrated that the tuba gene is essential for mitosis and nuclear migration. in this study we have deleted the tubb gene by replacing it with a selectable marker and have named this new allele tubb delta. the results demonstrate that the tubb gene is not required for vegetative growth or asexual reproduction, nor is it required for the initiation or early stages of ...19911936991
analysis of aspergillus nidulans conidial antigens and their prevalence in other aspergillus species.aspergillus nidulans is an ascomycetous fungus that reproduces asexually by forming multicellular conidiophores and uninucleate spores called conidia. these elements constitute the main vehicle for the transmission of this and other pathogenic aspergillus species and are the starting point of the different forms of aspergillosis. in order to use a. nidulans as a potential source of useful antigens for the immunodiagnosis of these diseases, we have examined the total protein composition of conidi ...19911937806
the influence of solvent stress on mms-induced genetic change in saccharomyces cerevisiae.mms induced mitotic recombination but not mitotic chromosome loss when tested in pure form in strain d61.m of saccharomyces cerevisiae, confirming previous results of albertini (1991), whereas in aspergillus nidulans it also induced chromosomal malsegregation in addition to mitotic recombination (käfer, 1988). however, induction of mitotic chromosome loss was observed in combination with strong inducers of chromosome loss such as the aprotic polar solvents ethyl acetate and to a lesser extent me ...19911944341
cell biology. never-in-mitosis in mitosis. 19911944528
the regulatory gene area mediating nitrogen metabolite repression in aspergillus nidulans. mutations affecting specificity of gene activation alter a loop residue of a putative zinc finger.the regulatory gene area mediating nitrogen metabolite repression in aspergillus nidulans has been sequenced and its transcript mapped and orientated. a single orf can encode a protein of 719 amino acids. a 52 amino acid region including a putative 'zinc finger' strongly resembles putative dna binding regions of the major regulatory protein of erythroid cells. the derived protein sequence also contains a highly acidic region possibly involved in gene activation and 22 copies of the motif s(t)pxx ...19901970293
comparison and cross-species expression of the acetyl-coa synthetase genes of the ascomycete fungi, aspergillus nidulans and neurospora crassa.the genes encoding the acetate-inducible enzyme acetyl-coenzyme a synthetase from neurospora crassa and aspergillus nidulans (acu-5 and faca, respectively) have been cloned and their sequences compared. the predicted amino acid sequence of the aspergillus enzyme has 670 amino acid residues and that of the neurospora enzyme either 626 or 606 residues, depending upon which of the two possible initiation codons is used. the amino acid sequences following the second alternative aug show 86% homology ...19901972535
restriction enzyme analysis of mitochondrial dna of the aspergillus flavus group: a. flavus, a. parasiticus, and a. nomius.mitochondrial dna restriction fragment length polymorphisms were identified that clearly distinguish aspergillus flavus, a. parasiticus, and a. nomius. mitochondrial dnas of a. flavus and a. parasiticus were found to be circular, and their size was estimated size to be 32 kilobases. a restriction map was constructed for the mitochondrial genome of an a. parasiticus isolate by using four restriction endonucleases. four genes tested were found to have the same order as in the mitochondrial genome ...19901976299
use of nuclear dna restriction fragment length polymorphisms to analyze the diversity of the aspergillus flavus group: a. flavus, a. parasiticus, and a. nomius.recombinant dna clones carrying high-copy or low-copy sequences from aspergillus nidulans and neurospora crassa were used to identify restriction fragment length polymorphisms (rflps) diagnostic for members of the a. flavus group: a. flavus, a. parasiticus, and a. nomius. these fungi were resolved into three distinct categories when they were grouped according to rflp patterns. subgroups within these categories were also evident. this limited rflp analysis of nuclear dna of members of the a. fla ...19901976300
premeiotic disruption of the neurospora crassa malate synthase gene by native and divergent dnas.repeat-induced point mutation (rip) has been used to generate new mutations in the previously uncharacterised gene for malate synthase in neurospora crassa. molecular clones carrying the am (nadp-glutamate dehydrogenase) gene and the malate synthase gene from either n. crassa or aspergillus nidulans have been introduced into neurospora as ectopic duplicate copies by transformation, selecting for the am+ function in a deletion host. a number of meiotic progeny derived from these transformants wer ...19901979142
sequences of isopenicillin n synthetase genes suggest horizontal gene transfer from prokaryotes to eukaryotes.evolutionary distances between bacterial and fungal isopenicillin n synthetase (ipns) genes have been compared to distances between the corresponding 5s rrna genes. the presence of sequences homologous to the ipns gene has been examined in dnas from representative prokaryotic organisms and ascomycotina. the results of both analyses strongly support two different events of horizontal transfer of the ipns gene from bacteria to filamentous fungi. this is the first example of such a type of transfer ...19901979440
restriction fragment length polymorphisms in isolates of aspergillus fumigatus probed with part of the intergenic spacer region from the ribosomal rna gene complex of aspergillus nidulans.differences in restriction fragment length polymorphisms (rflps) have been detected in isolates of aspergillus fumigatus. genomic dna from 11 isolates was digested with ecori, separated by electrophoresis, southern blotted and probed with dna from the intergenic spacer or non-transcribed spacer region of the rrna gene complex of aspergillus nidulans. three distinct rflp patterns were detected which differed from the control patterns observed with a. nidulans, aspergillus flavus and aspergillus n ...19901980128
aspergillus nidulans weta activates spore-specific gene expression.the aspergillus nidulans weta gene is required for synthesis of cell wall layers that make asexual spores (conidia) impermeable. in weta mutant strains, conidia take up water and autolyze rather than undergoing the final stages of maturation. weta is activated during conidiogenesis by sequential expression of the brla and abaa regulatory genes. to determine whether weta regulates expression of other sporulation-specific genes, its coding region was fused to a nutritionally regulated promoter tha ...19911986246
crna encodes a nitrate transporter in aspergillus nidulans.the nucleotide sequence of the aspergillus nidulans crna gene for the transport of the anion nitrate has been determined. the crna gene specifies a predicted polypeptide of 483 amino acids (molecular weight 51,769). a hydropathy plot suggests that this polypeptide has 10 membrane-spanning helices with an extensive hydrophilic region between helices six and seven. no striking homology was observed between the crna protein and other reported membrane proteins of either prokaryotic or eukaryotic or ...19911986367
molecular cloning and functional characterization of the pathway-specific regulatory gene nira, which controls nitrate assimilation in aspergillus nidulans.we have cloned an 11-kbp segment of the genomic dna of aspergillus nidulans which complements mutations in nira, the pathway-specific regulatory gene of the nitrate assimilation pathway. gene disruption in the corresponding region of the nuclear dna leads to a phenotype and a gene complementation pattern indistinguishable from that observed in known noninducible nira mutants. transformation studies with subclones of the 11-kbp genomic segment showed that a nonreverting null mutation nira87, maps ...19911990284
parallel activation of the nima and p34cdc2 cell cycle-regulated protein kinases is required to initiate mitosis in a. nidulans.we show that in aspergillus nidulans, p34cdc2 tyrosine dephosphorylation accompanies activation of p34cdc2 as an h1 kinase at mitosis. however, the nima5 mutation arrests cells in g2 with p34cdc2 tyrosine dephosphorylated and fully active as an h1 kinase. activation of nima is therefore not required for p34cdc2 activation. furthermore, mutation of nimt, which encodes a protein with 50% similarity to fission yeast cdc25, causes a g2 arrest and prevents tyrosine dephosphorylation of p34cdc2 but do ...19911913824
an autonomously replicating plasmid transforms aspergillus nidulans at high frequency.from an unstable aspergillus nidulans colony, resulting from transformation with an a. nidulans gene bank, a plasmid was reisolated which transformed a. nidulans at a frequency of 20,000 transformants per 10(6) protoplasts at near saturation levels of transforming dna. this represents a 250-fold enhancement of transformation efficiency over that found for typical integrative vectors such as pilj16, the plasmid used in gene bank constructions. the plasmid, designated arp1, is 11.5 kb in size, and ...19912013411
ecotoxicological aspects of aspergilli present in the phylloplane of stored leaves of chewing tobacco (nicotiana tobaccum).nine different species of aspergillus were isolated from the phylloplane of stored chewing tobacco (nicotiana tobaccum) of different ages. the maximum number of species were isolated from 12 and 18 month old leaves. a. ruber, a. ochraceus, a. flavus and a. nidulans were usually associated with older leaves while a. niger, a. fumigatus and a. flavus were isolated from 6 month old leaves. approximately 18% of aspergilli were found to be mycotoxigenic. sterigmatocystin was produced by three differe ...19912014047
regulation of invertase in aspergillus nidulans: effect of different carbon sources.aspergillus nidulans produces an extracellular beta-d-fructofuranoside fructohydrolase (invertase) when grown on a medium containing the beta-fructofuranosides sucrose or raffinose, indicating that synthesis is subject to induction by the substrate. on a growth medium containing sucrose, production was maximal at 15 h in cultures incubated at 28 c degrees. after this time the level of detectable invertase in the cultures declined. a proportion of the enzyme was secreted during the linear growth ...19912016586
isolation and nucleotide sequence of the aspergillus restrictus gene coding for the ribonucleolytic toxin restrictocin and its expression in aspergillus nidulans: the leader sequence protects producing strains from suicide.we describe the cloning and characterization of the gene coding for the ribotoxin restrictocin, from aspergillus restrictus (gene res, embl accession number x56176). this toxin is a potent inhibitor of protein synthesis in eucaryotes and is of potential interest as a component of immunotoxins. to analyze the mechanism of self-protection in the producing organism, the res gene was cloned into the vector pfb39 and introduced into aspergillus nidulans. the secretion of active restrictocin from tran ...19912020539
cloning and nucleotide sequence of the genomic ribonuclease t2 gene (rntb) from aspergillus oryzae.using synthetic oligonucleotide probes, we have cloned a genomic dna sequence encoding a ribonuclease (rnase) t2 gene (rntb) from aspergillus oryzae on a 4.8 kb hindiii fragment. dna sequence analysis of the rnase t2 revealed the following: (1) the gene is arranged as five exons and four introns; (2) the deduced amino acid sequence contains 239 amino acid residues of the mature enzyme. in addition, there exist 17 amino acid residues thought to be a signal peptide sequence at the n-terminus and 2 ...19911913876
heterologous transformation of cochliobolus lunatus.a dna mediated transformation system has been developed for the filamentous fungus cochliobolus lunatus. transformants were obtained by using plasmid pan 7-1 carrying the escherichia coli hygromycin b phosphotransferase gene (hph) fused to an aspergillus nidulans promoter. the integration of plasmid pan 7-1 into the fungal genome altered the ability of this microorganism to transform progesterone.19912037226
ph regulation of penicillin production in aspergillus shown by both bioassay and high-performance liquid chromatographic (hplc) analysis, penicillin g production by aspergillus nidulans is subject to regulation by the ph of the growth medium. penicillin titres were highest at alkaline ph and in strains carrying mutations in the regulatory gene pacc which mimics the effects of growth at alkaline ph. they were lowest at acid ph and in strains carrying mutations in the pala, palb, palc, pale or palf genes which mimic the effects of growth at acid p ...19912037230
a twin-reporter vector for simultaneous analysis of expression signals of divergently transcribed, contiguous genes in filamentous analyze the promoter region(s) of divergently transcribed fungal genes, a twin-reporter vector was constructed. this vector contains two divergently oriented reported genes, encoding escherichia coli beta-glucuronidase (uida) and e. coli beta-galactosidase (lacz). terminator regions of the aspergillus nidulans nitrate and nitrite reductase-encoding genes, niad and niia, respectively, have been cloned 3' to the reporter genes to ensure proficient transcription termination of the reporter genes ...19911916271
cloning and characterization of an amidase gene from rhodococcus species n-774 and its expression in escherichia coli.for investigation of an unknown open reading frame which is present upstream of the nitrile hydratase (nhase) gene from rhodococcus sp. n-774, a longer dna fragment covering the entire gene was cloned in escherichia coli. nucleotide sequencing and detailed subcloning experiments predicted a single open reading frame consisting of 521 amino acid residues of mr 54,671. the amino acid sequence, especially its nh2-terminal portion, showed significant homology with those of indoleacetamide hydrolases ...19912001397
glycerol catabolism in aspergillus nidulans.glycerol is catabolized in aspergillus nidulans by glycerol kinase and a mitochondrial fad-dependent sn-glycerol 3-phosphate dehydrogenase. the levels of both enzymes are controlled by carbon catabolite repression and by specific induction. biochemical and genetical analyses show that dihydroxyacetone and d-glyceraldehyde are converted into glycerol and then catabolized by the same pathway. d-glyceraldehyde can be reduced by nadp(+)-dependent glycerol dehydrogenase or by alcohol dehydrogenase i, ...19912033381
correct intron splicing generates a new type of a putative zinc-binding domain in a transcriptional activator of aspergillus nidulans.alcr is the pathway-specific transcriptional activator of the ethanol regulon in the filamentous fungus, aspergillus nidulans. the deduced amino acid sequence of a cdna clone, including the 5' part of the alcr-mrna, shows that a putative zn-binding domain of the all-cysteine class, exemplified by gal4 is present. this structure presents some striking features. at variance with other structures of this class, the binding domain is strongly asymmetrical. model building indicates that the zinc-bind ...19912053973
adenylate kinase isoenzymes in aspergillus nidulans.adenylate kinase isoenzymes localised in the mitochondria and in the cytosol have been detected in extracts of glucose-grown aspergillus nidulans using specific staining after electrophoresis on cellulose acetate. the isoenzymes have similar km values for amp, adp and mgatp2- but may differ in the mechanism used for internucleotide phosphate transfer.19912040420
the amdr product and a ccaat-binding factor bind to adjacent, possibly overlapping dna sequences in the promoter region of the aspergillus nidulans amds gene.the amds gene of aspergillus nidulans is regulated by a number of positively acting regulatory genes which act additively and independently. using gel mobility shift assays with crude nuclear extracts we show here that the product of one of these regulatory genes, the amdr gene, binds to dna fragments containing part of the promoter region of the amds gene. this confirms the earlier prediction from dna sequence data that amdr encodes a dna-binding protein containing a cysteine-rich 'zinc finger' ...19912041742
delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase from aspergillus nidulans. molecular characterization of the acva gene encoding the first enzyme of the penicillin biosynthetic pathway.the aspergillus nidulans gene (acva) encoding the first catalytic steps of penicillin biosynthesis that result in the formation of delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine (acv), has been positively identified by matching a 15-amino acid segment of sequence obtained from an internal cnbr fragment of the purified amino-terminally blocked protein with that predicted from the dna sequence. acva is transcribed in the opposite orientation to ipna (encoding isopenicillin n synthetase), with an ...19912061333
molecular cloning and characterization of the arod gene encoding 3-dehydroquinase from salmonella typhi.the arod gene from salmonella typhi, encoding 5-dehydroquinate hydrolyase (3-dehydroquinase), has been cloned into escherichia coli and the dna sequence determined. the arod gene was isolated from a cosmid gene bank by complementation of an s. typhimurium arod mutant. analysis of the dna sequence revealed the presence of an open reading frame capable of encoding a protein of 252 amino acids with a calculated mr of 27706. comparison of the deduced s. typhi 3-dehydroquinase protein sequence with t ...19912045778
in vitro studies with nine known or suspected spindle poisons: results in tests for chromosome malsegregation in aspergillus nidulans.within the framework of a coordinated collaborative study for evaluating assays for aneuploidy, nine known or suspected spindle poisons were tested in mitotic segregation assays with aspergillus nidulans. experiments with a. nidulans diploid strain p1 revealed a statistically significant increase of whole chromosome segregants (non-disjunctional diploids and haploids) after treatments with chloral hydrate (ch), thiabendazole (tb), thimerosal (tm) econazole (ez) and hydroquinone (hq). the latter ...19912056914
rodletless, a new aspergillus developmental mutant induced by directed gene inactivation.the aspergillus nidulans can41 transcription unit is activated by the brla regulatory gene early during development of the asexual reproductive apparatus, the conidiophore. disruption of can41 results in a novel mutant phenotype in which conidiophore cells and spores lack an external wall layer, the rodlet layer, making them less hydrophobic than in the wild type and leading to inefficient spore dispersal. the rodletless mutation defines a new locus on chromosome iii, roda. roda encodes a small, ...19912065971
expression of the aspergillus niger glucose oxidase gene in a. niger, a. nidulans and saccharomyces cerevisiae.we report the cloning of the aspergillus niger glucose oxidase gene and its use to elevate glucose oxidase productivity in a. niger by increasing the gene dosage. in addition, the gene has been introduced into a. nidulans where it provides the novel capacity to produce glucose oxidase. a plasmid, in which dna encoding the mature form of glucose oxidase was preceded by a saccharomyces cerevisiae secretion signal, effected high-level production of extracellular glucose oxidase in this yeast.19902076553
isolation and transcriptional characterization of a morphological modifier: the aspergillus nidulans stunted (stua) gene.the functions of at least four potential regulatory genes are known to overlap temporally during elaboration of the multicellular asexual reproductive apparatus (conidiophore) of aspergillus nidulans. one of these, the stua (stunted) gene, has been previously classified as a morphological modifier essential for correct spatial organization of the conidiophore. the gene was cloned by complementation of a strain carrying the stua1 mutation and has been localized to a 5.0 kb kpni fragment that enco ...19912062309
fungi of virgin and cultivated soil of salhiah desert, egypt.27 species and 13 genera of fungi were identified from virgin and cultivated soil of salhiah. the most abundant species of phosphate solubilizing fungi were aspergillus nidulans, a. niger, a flavus, penicillium lilacinum, p. frequentans and fusarium moniliforme. on cellulose agar the most prevalent species were chaetomium bostrychodes, c. olivaceum, humicola fuscoatra, aspergillus flavus, a. nidulans, a. niger, a. ochraceus, fusarium solani and f. oxysporum. on xylan agar aspergillus fumigatus, ...19902077791
genetic analysis of suppressors of the vea1 mutation in aspergillus nidulans.light-dependent conidiation in the filamentous ascomycete, aspergillus nidulans, is contingent on the allelic state of the velvet (vea) gene. light dependence is abolished by a mutation in this gene (vea1), which allows conidiation to occur in the absence of light. we have isolated and characterized six extragenic suppressors of vea1 that restore the light-dependent conidiation phenotype. alleles of four genes, defined by complementation tests, were subjected to extensive genetic and phenotypic ...19902076818
beta-lactam antibiotic biosynthetic genes have been conserved in clusters in prokaryotes and eukaryotes.a cosmid clone containing closely linked beta-lactam antibiotic biosynthetic genes was isolated from a gene library of flavobacterium sp. sc 12,154. the location within the cluster of the dna thought to contain the gene for delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase (acvs), the first step in the beta-lactam antibiotic biosynthetic pathway, was identified by a novel method. this dna facilitated the isolation, by cross-hybridization, of the corresponding dna from streptomyces clav ...19902107074
a critical arginine in the large subunit of ribulose bisphosphate carboxylase/oxygenase identified by site-directed mutagenesis.rapid inactivation by phenylglyoxal of ribulose bisphosphate carboxylase/oxygenase (ribulose-p2 carboxylase) from the cyanobacterium anacystis nidulans suggests the presence of an essential arginine, the modification of which is reduced in the presence of the substrate ribulose bisphosphate. arginine 292 in the large subunit of ribulose-p2 carboxylase from a. nidulans was chosen for site-directed mutagenesis studies on the basis of the complete conservation of this residue in corresponding seque ...19902108139
brla requires both zinc fingers to induce development.expression of the aspergillus nidulans brla gene induces a developmental pathway leading to the production of asexual spores. we have introduced mutations into brla that are expected to disrupt either or both cys2-his2 zn(ii) coordination sites postulated to exist in the brla polypeptide. the resultant brla alleles fail to induce either the asexual reproductive pathway or the expression of development-specific genes. these data support the hypothesis that brla encodes a nucleic acid-binding prot ...19902108321
chromosome-specific recombinant dna libraries from the fungus aspergillus nidulans.development of physical genomic maps is facilitated by identification of overlapping recombinant dna clones containing long chromosomal dna inserts. to simplify the analysis required to determine which clones in a genomic library overlap one another, we partitioned aspergillus nidulans cosmid libraries into chromosome-specific subcollections. the eight a. nidulans chromosomes were resolved by pulsed field gel electrophoresis and hybridized to filter replicas of cosmid libraries. the subcollectio ...19912057366
cloning and expression of a hybrid streptomyces clavuligerus cefe gene in penicillium chrysogenum.a hybrid cefe gene was constructed by juxtaposing promoter sequences from the penicillium chrysogenum pcbc gene to the open reading frame of the streptomyces clavuligerus cefe gene. in s. clavuligerus the cefe gene codes for the enzyme penicillin n expandase [also known as deacetoxycephalosporin c synthetase (daocs)]. to insert the hybrid cefe gene into p. chrysogenum the vector pps65 was constructed; pps65 contains the hybrid cefe gene and the aspergillus nidulans amds gene. the amds gene encod ...19902111228
characterization of cryptic plasmids from marine cyanobacteria and construction of a hybrid plasmid potentially capable of transformation of marine cyanobacterium, synechococcus sp., and its transformation.among forty strains of marine cyanobacteria isolated in our laboratory, five strains had 1-3 different plasmids. the unicellular marine cyanobacterium, synechococcus sp. nkbg 042902, contains at least three plasmids (psy09, psy10, and psy11). however, these plasmids are cryptic. therefore, a hybrid plasmid pusy02 containing the 1.4-kb hindiii fragment of psy11 and escherichia coli plasmid puc18 was constructed. the plasmid pusy02 transformed both marine synechococcus sp. nkbg042902-yg1116, which ...19902112896
nitrate reactive structural gene mutants of aspergillus nidulans.two strains characterized as niad structural gene mutants in aspergillus nidulans produce a nitrate reductase which retains the ability to react with nitrate while lacking the ability to oxidize its naturally occurring substrate nadph. fifteen such nitrate reactive niad strains exhibited strong interallelic complementation when tested against strains bearing point mutations in eleven other loci essential to induction and synthesis of nitrate reductase in aspergillus. fourteen representatives of ...19912062247
upstream elements repress premature expression of an aspergillus developmental regulatory gene.the aspergillus nidulans abaa gene regulates intermediate steps in asexual reproductive development and is itself developmentally regulated. an 822-base-pair dna fragment from the abaa 5'-flanking region is sufficient to drive developmentally appropriate expression of the escherichia coli lacz gene. deletion analysis showed that this fragment contains elements that repress transcription in vegetative cells and immature conidiophores and that activate transcription later during development. a 45- ...19902117702
a case of cerebral aspergillosis caused by aspergillus nidulans. clinical, pathologic and mycologic identifications.a case of cerebral aspergillosis is reported, the presenting symptom was numbness of right face, which worsened after one year. ct-scan showed two enhanced low-density patches in the anterior and basal parts of right temporal lobe. during operation, an abscess in the deep part of right temporal lobe was revealed. the patient gradually felt amaurosis and oculomotor palsy of right eye. about six months later, she died from intracranial hypertension. biopsy, as well as autopsy findings suggested fu ...19902119968
molecular characterization of the acyl-coenzyme a:isopenicillin n acyltransferase gene (pende) from penicillium chrysogenum and aspergillus nidulans and activity of recombinant enzyme in escherichia coli.the final step in the biosynthesis of beta-lactam antibiotics in penicillium chrysogenum and aspergillus nidulans involves removal of the l-alpha-aminoadipyl side chain from isopenicillin n (ipn) and exchange with a nonpolar side chain. the enzyme catalyzing this reaction, acyl-coenzyme a:isopenicillin n acyltransferase (acyltransferase), was purified from p. chrysogenum and a. nidulans. based on nh2-terminal amino acid sequence information, the acyltransferase gene (pende) from p. chrysogenum a ...19902120195
functional expression of 8-hydroxy-5-deazaflavin-dependent dna photolyase from anacystis nidulans in streptomyces coelicolor.the gene encoding anacystis nidulans 5-deazaflavin-dependent photolyase (phr) was inserted into the streptomyces vector pij385 to form a transcriptional fusion with the neomycin resistance (aph) gene. the resulting plasmid, panpl, was introduced into streptomyces coelicolor, a host which exhibits no detectable photolyase activity and provides 5-deazaflavins. transformants expressed functional photolyase and could be cultured at much higher cell densities than a. nidulans. a two-step affinity pro ...19902120199
analysis of delta-l-alpha-aminoadipyl-l-cysteinyl-d-valine by ion chromatography and pulsed amperometric detection.a novel high-performance liquid chromatography (hplc) method is presented for the detection and trace level determination of the tripeptide delta-l-alpha-aminoadipyl-l-cysteinyl-d-valine (acv). the tripeptide, an intermediate in penicillin production, is derived from fungal fermentation. the technique relies on ion-exchange separation of the tripeptide on an anion-exchange column followed by detection by reduction on a gold electrode using pulsed amperometry. the sensitivity of direct determinat ...19902120274
qualitative and quantitative changes in beta-1,4-glucosidase accompanying growth of aspergillus nidulans.a comparative study of the wild type a. nidulans and a mutant strain aco-t69 (lacking conidia and cleistothecia) revealed the better production of beta-1,4-glucosidase in the former. the relative distribution of the enzyme levels in various morphological structures viz. somatic hyphae, spores and cleistothecia also showed a variation. highest specific activity was found in the cleistothecial extracts. the electrophoretic analysis of the wild type strain demonstrated the presence of three isoenzy ...19902120420
functional elements in the promoter region of the aspergillus nidulans gpda gene encoding glyceraldehyde-3-phosphate dehydrogenase.analysis of the promoter region of the highly expressed aspergillus nidulans gpda gene is described. the nucleotide (nt) sequence of a 1.3-kb region upstream from the atg was determined. comparison with promoter regions of other aspergillus and neurospora genes revealed several regions of similar sequence. both random and site-specific mutations were introduced into the promoter region of the gpda gene, and the resulting mutant promoters were fused to the escherichia coli lacz gene. the construc ...19902121607
n-acetyl-6-hydroxytryptophan oxidase, a developmentally controlled phenol oxidase from aspergillus nidulans.we have purified a specific phenol oxidase which is produced during conidiophore development in the fungus aspergillus nidulans. two active forms (a and b) have molecular masses of 50 and 48 kda respectively; they have identical n-termini (24 residues). we have analysed the metal ion content of the b form; it is unusual in consisting of one zinc and two copper atoms per molecule. a temperature-sensitive mutant (ivob192) produces a thermolabile enzyme, implying that ivob is the structural locus. ...19902126551
isolation and sequence analysis of a beta-tubulin gene from aspergillus flavus and its use as a selectable altered beta-tubulin gene that confers resistance to benomyl [whose active ingredient is 2-(methoxycarbonylamino)benzimidazole (mbc)] was isolated from a dna library of aspergillus flavus and used as a selectable marker for transformation. the beta-tubulin gene was cloned into a plasmid vector containing the pyr-4 gene of neurospora crassa, and transformants were selected either for uracil prototrophy or mbc resistance. transformants selected for uracil prototrophy were of three phenotypic cl ...19902128007
[lung mycoses caused by opportunistic fungi]. 19902128860
structure and molecular mechanics of ferrirhodin.c41h64fen9o17.7 1/2h2o, mr = 1146.0, orthorhombic, p2(1)2(1)2(1), a = 9.740 (7), b = 16.764 (10), c = 32.632 (17) a, v = 5328 (6) a3, z = 4, d chi = 1.43 g cm-3, mo k alpha, lambda = 0.71069 a, mu = 3.26 cm-1, f(000) = 2428, t = 138 (2) k, r = 0.0986 for 3543 observed reflections. ferrirhodin, a ferrichrome siderophore (iron transport agent) was isolated from low-iron cultures of aspergillus versicolor and a. nidulans. the compound is isomeric with another microbial siderophore, ferrirubin, but ...19902088417
adenosine triphosphatases in p-fluorophenylalanine sensitive and resistant strains of aspergillus nidulans. 19902144842
immunoprecipitation distinguishes non-overlapping groups of snrnps in schizosaccharomyces pombe.the large number of snrnas in the fission yeast schizosaccharomyces pombe can be divided into four non-overlapping groups by immunoprecipitation with antibodies directed against mammalian snrnp proteins. 1) of the abundant snrnas, anti-sm sera precipitate only the spliceosomal snrnas u1, u2, u4, u5 and u6. surprisingly, three sm-sera tested distinguish between u2, u4 and u5 and u1 from s.pombe; one precipitating only u1 and two precipitating u2, u4 and u5 but not u1. 2) a group of 11 moderately ...19902144896
novel potential mitotic motor protein encoded by the fission yeast cut7+ gene.the structure equivalent to higher eukaryotic centrosomes in fission yeast, the nuclear membrane-bound spindle pole body, is inactive during interphase. on transition from g2 to m phase of the cell cycle, the spindle pole body duplicates; the daughter pole bodies seed microtubules which interdigitate to form a short spindle that elongates to span the nucleus at metaphase. we have identified two loci which, when mutated, block spindle formation. the predicted product of one of these genes, cut7+, ...19902145514
acyl coenzyme a: 6-aminopenicillanic acid acyltransferase from penicillium chrysogenum and aspergillus nidulans.a study of the final stages of the biosynthesis of the penicillins in penicillium chrysogenum has revealed two types of enzyme. one hydrolyses phenoxymethyl penicillin to 6-aminopenicillanic acid (6-apa). the other, also obtained from aspergillus nidulans, transfers a phenylacetyl group from phenylacetyl coa to 6-apa. the acyltransferase, purified to apparent homogeneity, had a molecular mass of 40 kda. it also catalyses the conversion of isopenicillin n (ipn) to benzylpenicillin (pen g) and hyd ...19902110531
[host-vector systems in filamentous fungi]. 19902148397
the upstream region of the ipns gene determines expression during secondary metabolism in aspergillus nidulans.we have constructed a translational fusion between the isopenicillin-n-synthetase-encoding gene (ipns) of aspergillus nidulans and the lacz gene of escherichia coli. recombinant strains carrying a single copy of the fusion integrated at the ipns locus produced beta-galactosidase (beta gal) during secondary metabolism. integration of the fusion at the argb locus results in a situation in which the only 5'-flanking sequences of the ipns gene upstream from the chimeric fused gene are those included ...19902115487
mutation of a gene that encodes a kinesin-like protein blocks nuclear division in a. a. nidulans, the temperature-sensitive cell cycle mutation bimc4 causes an elevated mitotic index at restrictive temperature. under restrictive conditions the mutation interferes with separation of the spindle pole bodies, causes abnormal spindle morphology, and prevents nuclear division. we have cloned and sequenced the wild-type bimc gene. the predicted protein product has homology to drosophila kinesin heavy chain. we conclude that this kinesin-like protein has an important role in nuclear ...19902138511
the beta-tubulin gene of epichloë typhina from perennial ryegrass (lolium perenne).epichloë typhina is a biotrophic fungal pathogen which causes choke disease of pooid grasses. the anamorphic state, acremonium typhinum, is placed in the section albo-lanosa along with related, mutualistic, seed-disseminated endophytes. as an initial study of gene structure and evolution in epichloë and related endophytes, the beta-tubulin gene, tub2, of the perennial ryegrass choke pathogen (etprg) was cloned and sequenced. the coding sequence and the predicted beta-tubulin amino acid sequence ...19902147581
induced expression of the aspergillus nidulans qute gene introduced by transformation into neurospora crassa.the qa-2 gene of neurospora crassa encodes catabolic dehydroquinase which catabolizes dehydroquinic acid to dehydroshikimic acid. the qute gene of aspergillus nidulans corresponds to the qa-2 gene of n. crassa. the plasmid peh1 containing the qute gene from a. nidulans was used to transform a qa-2- strain of n. crassa. in southern blot analyses, dnas isolated from these transformants hybridized specifically to the qute gene probe. northern blot analyses indicated that qute mrna was produced in t ...19902148798
of moulds and men, or two fingers are not better than one. 19902149222
abaa controls phialide differentiation in aspergillus nidulans.aspergillus nidulans is an ascomycetous fungus that reproduces asexually by forming multicellular conidiophores and uninucleate spores called conidia. loss of function mutations in the abacus a (abaa) regulatory locus result in formation of aberrant conidiophores that fail to produce conidia. wild-type conidiophores form two tiers of sterigmata. the first tier, metulae, divide to produce the second tier, phialides. phialides are sporogenous cells that produce conidia through a specialized apical ...19902152124
cloned manganese superoxide dismutase reduces oxidative stress in escherichia coli and anacystis nidulans.the mn superoxide dismutase gene of escherichia coli was subcloned into the e. coli-anacystis nidulans shuttle vector psg111 to make the plasmid pmyg1. transformation of e. coli hb101 with pmyg1 resulted in a 6-fold increase in superoxide dismutase activity. there was also induction of mn superoxide dismutase in the transformants upon exposure to paraquat, as evidenced by dramatically increased levels of the mn superoxide dismutase polypeptide in cytoplasmic extracts and a 16-fold further increa ...19902157207
endo-exonuclease of aspergillus nidulans.endo-exonuclease (ee) has been found in both active and inactive, but trypsin-activatable, forms in aspergillus nidulans. active ee was present mainly in nuclei, mitochondria, and vacuoles, while trypsin-activatable ee was mainly in the cytosol. the active form accounts for over 90% of the neutral deoxyribonuclease activity extracted from mycelia. a single strand (ss) dna-binding ee associated with a 28 kilodalton (kda) polypeptide was partially purified and characterized. it was found to closel ...19902161674
regulation of inorganic sulfate activation in filamentous fungi. allosteric inhibition of atp sulfurylase by 3'-phosphoadenosine-5'-phosphosulfate.atp sulfurylases from penicillium chrysogenum, penicillium duponti, aspergillus nidulans, and neurospora crassa are strongly inhibited by 3'-phosphoadenosine-5'-phosphosulfate (paps), the product of the second (adenosine-5'-phosphosulfate kinase-catalyzed) reaction in the two-step activation of inorganic sulfate. the v versus [paps] plots are sigmoidal. at physiological concentrations of mgatp (0.17-3 mm) and so4(2-) (0.4-10 mm), the [i]0.5 for paps inhibition of the p. chrysogenum enzyme is 35- ...19902162344
cloning, characterization of the acyl-coa:6-amino penicillanic acid acyltransferase gene of aspergillus nidulans and linkage to the isopenicillin n synthase gene.the pende gene encoding acyl-coa:6-amino penicillanic acid acyltransferase (aat), the last enzyme of the penicillin biosynthetic pathway, has been cloned from the dna of aspergillus nidulans. the gene contains three introns which are located in the 5' region of the open reading frame. it encodes a protein of 357 amino acids with a molecular weight of 39,240 da. the pende gene of a. nidulans shows 73% similarity at the nucleotide level with the pende gene of penicillium chrysogenum. the a. nidula ...19902166227
efficient integrative transformation of the phytopathogenic fungus alternaria alternata mediated by the repetitive rdna attempt was made to transform alternaria alternata protoplasts using a plasmid vector, pdh25, bearing the escherichia coli hygromycin b (hy) phosphotransferase gene (hph) under the control of the aspergillus nidulans trpc promoter. transformants arose on a selective medium containing 100 micrograms hy/ml. there were two types of transformants, forming large and small colonies on the selective medium. transformation with one microgram of the vector produced an average of 4.5 large colonies and ...19902169442
insertional inactivation and cloning of the wa gene of aspergillus nidulans.we describe examples of wa gene inactivation (resulting in white conidiospores) obtained during transformation of aspergillus nidulans. one wa- transformant was obtained by transformation with a prn+ plasmid of a strain with green conidia (wa+) which was unable to catabolize l-proline (prn-). this transformant contains a very large number of plasmid copies integrated at a single site inseparable from the wa locus. passage of this transformant through the sexual cycle generated a variety of novel ...19902172077
spatial and biological characterisation of the complete quinic acid utilisation gene cluster in aspergillus nidulans.heterologous probing of restriction digests of chromosomal dna from aspergillus nidulans with radioactively labelled probes encoding dehydroshikimate dehydratase (qa-4) and a repressor gene (qa1-s) from neurospora crassa revealed a pattern of hybridisation inconsistent with an equivalent single copy of each gene in a. nidulans. screening of size-selected and total genome a. nidulans dna libraries allowed the isolation of four unique classes of sequence, two of which hybridised to the qa-4 probe, ...19902175387
transformation of aspergillus giganteus to hygromycin b resistance.a wild strain of a. giganteus was transformed to hygromycin b resistance using a bacterial resistance gene under the control of a. nidulans sequences. stable transformants arose by heterogenous integration, mainly of tandem repeats of vector dna at various sites in the host genome. between 6 and 30 resistant colonies were obtained per microgram dna per 3 x 10(3) viable protoplasts. vector dna could be recovered by transformation of escherichia coli with undigested genomic dna from aspergillus gi ...19902178785
chromosomal mapping of an alcc disruption with respect to amda in aspergillus nidulans.we report the use of the ribob gene for a gene replacement in the alcc gene of aspergillus nidulans, and show by "reverse genetics" that the alcc gene is very closely linked to the amda gene.19902178787
purification and characterization of cellulolytic enzymes produced by aspergillus nidulans.three exo-glucanases, two endo-glucanases and two beta-glucosidases were separated and purified from the culture medium of aspergillus nidulans. the optimal assay conditions for all forms of cellulase components ranged from ph 5.0 to 6.0 and 50 degrees c and 65 degrees c for exo-glucanases and endo-glucanases but 35 degrees c and 65 degrees c for beta-glucosidases. a close relation of enzyme stability to their optimal ph range was observed. all the cellulase components were stable for 10 min at ...19902179198
genotoxicity studies on the organophosphorus insecticide chloracetophone.chloracetophone (o,o-dimethyl-2,2,2-trichloro-1-(chloroacetoxy)phosphonate), a new insecticide of the organophosphorus group of pesticides, was tested for genotoxicity in a variety of systems with different genetic end-points and varying parameters. the test systems included 2 microbial systems, salmonella and aspergillus for point mutations and mitotic segregation, respectively, and human lymphocyte cultures and mammalian bone marrow cells (from rats and hamsters treated acutely and subacutely) ...19902179715
conidium differentiation in aspergillus nidulans wild-type and wet-white (weta) mutant strains.conidium (asexual spore) differentiation in wild-type and the wet-white (weta) mutant of aspergillus nidulans was compared in intact chains of successively older conidia. carbohydrate cytochemistry helped define three stages (stages i, ii, and iii) of wild-type conidium maturation on the basis of changes in the ultrastructure and composition of the conidium wall. conidia of the weta6 mutant strain formed normally but failed to mature during stages ii and iii. specifically, the inner wall layer o ...19902180753
mutants of aspergillus nidulans able to grow at extremely acidic ph acidify the medium less than wild type when grown at more moderate ph.mutations conferring the ability to grow on extremely acidic media have been selected in the fungus aspergillus nidulans and map to at least four genes. the mutations fall into two classes: those that confer acid resistance in media of both high and low buffering capacity and those that confer resistance only in media of low buffering capacity. in growth media of more moderate ph mutations of both classes result in reduced acidification of the medium.19902182381
a mutation affecting amds expression in aspergillus nidulans contains a triplication of a cis-acting regulatory aspergillus nidulans expression of the acetamidase structural gene, amds, is under the control of at least four regulatory genes including the trans-acting amda regulatory gene. a cis-acting mutation (amdi66) consisting of an 18 bp duplication in the 5' region of the amds gene results in very high levels of acetamidase activity but only in strains carrying semi-dominant mutations in the amda gene. in selecting for increased amds expression in an amdi66 and a+ strain, an a. nidulans strain wit ...19902187153
chloroacetaldehyde is a powerful inducer of mitotic aneuploidy in aspergillus nidulans.the vinyl chloride metabolite chloroacetaldehyde (caa) was tested for the induction of mitotic chromosome malsegregation in aspergillus nidulans. exposure of germinating conidia to caa (16-64 microm) produced high rates of abnormal colonies with segregation of the whole first chromosome in the diploid strain p1, and abnormal, putative hyperploids in the haploid strain 35, indicating that caa primarily induces abnormal chromosome segregation. comparative assays with the known spindle poison chlor ...19902188069
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