PMID(sorted descending)
sterigmatocystin biosynthesis in aspergillus nidulans requires a novel type i polyketide synthase.a filamentous fungus, aspergillus nidulans, produces the carcinogenic mycotoxin sterigmatocystin (st), which is a polyketide-derived secondary metabolite. a gene (pksst) encoding the st polyketide synthase (pksst) in a. nidulans was cloned, sequenced, and characterized. large induced deletion mutants, which did not make st or any st intermediates, were used to identify genes associated with st biosynthesis. among the transcripts detected within the deletion region, which showed developmental exp ...19957642507
carbon source-dependent regulation of the acetyl-coenzyme a synthetase-encoding gene acs1 from saccharomyces cerevisiae.the yeast acs1 gene, encoding acetyl-coenzyme a synthetase (acs), was cloned using colony hybridization and a faca probe from aspergillus nidulans. the complete sequence of 1.5 kb of the acs1 upstream region was determined. northern hybridization revealed a strong depression of acs1 transcripts in a strain grown on the nonfermentable carbon sources, acetate or ethanol. in contrast to a previous report, delta acs1 null mutants did not exhibit a growth defect on acetate medium. indeed, enzyme assa ...19957642141
structure, organization and promoter expression of the actin-encoding gene in trichoderma reesei.the single gene encoding actin (act) in the cellulolytic filamentous fungus trichoderma reesei (tr) has been isolated and characterized. the gene contains five introns located in identical positions when compared to the putative ancestral actin genes (act) present in thermomyces lanuginosus and aspergillus nidulans. the 5' untranslated region (utr) of the gene contains a tata-like sequence (taata), a c + t-rich region and a potential ccaat motif. this region was used as a homologous promoter to ...19957642121
effects of leader sequences upon the heterologous expression of restrictocin in aspergillus nidulans and aspergillus niger.the effects of altered leader sequences on the secretion and localization of restrictiocin expression in aspergillus nidulans and aspergillus niger were investigated. the region encoding the leader sequence of the aspergillus restrictus restrictocin (res) gene was altered and variants were expressed under the glucoamylase (glaa) promoter in a. nidulans and a. niger. the entire restrictocin leader sequence was replaced by the glaa leader sequence in one variant. in another, the signal sequence of ...19957641142
the basal level of transcription of the alc genes in the ethanol regulon in aspergillus nidulans is controlled both by the specific transactivator alcr and the general carbon catabolite repressor the a. nidulans ethanol utilization pathway, specific induction is mediated by the transactivator alcr which is subject to strong positive autogenous regulation and activates the transcription of the two structural genes alca and alda. carbon catabolite repression is mediated by crea which represses directly the transacting gene alcr and the two structural genes. we show here that the basal expression of the alcr and alca genes is also controlled by the two regulatory circuits, positively by ...19957635218
isolation of a functional homolog of the cell cycle-specific nima protein kinase of aspergillus nidulans and functional analysis of conserved investigate the degree of conservation of the cell cycle-specific nima protein kinase of aspergillus nidulans, and to help direct its functional analysis, we cloned a homolog (designated nim-1) from neurospora crassa. over the catalytic domain nim-1 is 75% identical to nima, but overall the identity drops to 52%. nim-1 was able to functionally complement nima5 in a. nidulans. mutational analysis of potential activating phosphorylation sites found in nima, nim-1, and related protein kinases wa ...19957629122
sequence and structure of penicillium chrysogenum phog, homologous to an acid phosphatase-encoding gene of aspergillus nidulans.a penicillium chrysogenum (pc) gene (phog), homologous to an aspergillus nidulans (an) gene which confers phosphate-non-repressible acid phosphatase (apase) activity, has been cloned and sequenced. the 2.9-kb genomic sequence corresponds to two orfs of 149 and 1630 bp encoding a protein of 593 amino acids (aa). as verified by cdna sequencing, the coding region is interrupted by an 85-bp intron. the deduced aa sequence of phog reveals 61% aa identity to the translated long orf of the an apase-enc ...19957628710
activation of the aspergillus pacc transcription factor in response to alkaline ambient ph requires proteolysis of the carboxy-terminal moiety.extremes of ph are an occupational hazard for many microorganisms. in addition to efficient ph homeostasis, survival effectively requires a regulatory system tailoring the syntheses of molecules functioning beyond the cell boundaries (permeases, secreted enzymes, and exported metabolites) to the ph of the growth environment. our previous work established that the zinc finger pacc transcription factor mediates such ph regulation in the fungus aspergillus nidulans in response to a signal provided ...19957628696
malvolio, the drosophila homologue of mouse nramp-1 (bcg), is expressed in macrophages and in the nervous system and is required for normal taste behaviour.we report the sequence, expression pattern and mutant phenotype of malvolio (mvl), the drosophila homologue of mammalian natural resistance-associated macrophage proteins (nramps). in the mouse, this novel transporter is encoded by bcg, a dominant gene that confers natural resistance to intracellular parasites. mvl was identified in a screen for mutants that affect taste behaviour. we show that loss-of-function as well as insertional mutants in mvl display defects in taste behaviour with no alte ...19957621816
niaa, the structural nitrate reductase gene of phytophthora infestans: isolation, characterization and expression analysis in aspergillus nidulans.the nitrate reductase (nr) gene niaa of the oomycete phytophthora infestans was selected from a gene library by heterologous hybridization. niaa occurs as a single-copy gene ant its expression is regulated by the nitrogen source. the nucleotide sequence of niaa was determined and comparison of the deduced amino-acid sequence of 902 residues with nrs of higher fungi and plants revealed a significant homology, particularly within the three cofactor-binding domains for molybdenum, heme and fad. the ...19957614559
aspergillus nidulans mutants affected in acetate metabolism isolated as lipid nonutilizers.interest in extracellular fungal lipases has increased mainly because of their industrial applications. however, no studies have been done on a genetically well characterized filamentous fungus like aspergillus nidulans. here we show that a. nidulans produces an extracellular lipase when grown in solid or liquid cultures containing lipids as carbon source. this lipase is glucose-repressed in a crea-independent fashion. seven mutants isolated by their inability to utilize lipids as sole carbon so ...19957614370
nudf, a nuclear migration gene in aspergillus nidulans, is similar to the human lis-1 gene required for neuronal migration.during a study of the genetics of nuclear migration in the filamentous fungus aspergillus nidulans, we cloned a gene, nudf, which is required for nuclear migration during vegetative growth as well as development. the nudf protein level is controlled by another protein nudc, and extra copies of the nudf gene can suppress the nudc3 mutation. nudf encodes a protein with 42% sequence identity to the human lis-1 (miller-dieker lissencephaly-1) gene, which is required for proper neuronal migration dur ...19957612965
a single amino acid change in a pathway-specific transcription factor results in differing degrees of constitutivity, hyperinducibility and derepression of several structural genes.unyc462 is a gain-of-function mutation in the purine catabolism positive regulatory gene of aspergillus nidulans. this allele leads to a constitutive, hyperinducible and derepressed expression of a least three genes controlled by uay, and this occurs at different levels depending on the target gene. the uayc462 allele was mapped physically in relation to known loss-of-function alleles and sequenced. uayc462 is a one-base change in codon 222, resulting in a serine to leucine change. we propose th ...19957602582
the positively acting amda gene of aspergillus nidulans encodes a protein with two c2h2 zinc-finger motifs.semi-dominant mutations in the amda gene lead to elevated expression of the gene encoding acetamidase, amds. these mutations also cause constitutive expression of the acetate-inducible gene, acia. in the amds 5' regulatory region, two cis-acting mutations, amdl66 and amdl666, have been isolated which specifically affect amda activation of amds. these mutations are a duplication and a triplication of an 18 bp ga-rich sequence, thought to define the amda site of action within the amds promoter reg ...19957596297
nucleotide sequence and characterization of the large mitochondrial rrna gene of penicillium urticae, and its comparison with those of other filamentous fungi.the nucleotide sequence of a large rrna gene and its flanking regions in cloned fragments of mitochondrial dna from a patulin producer, penicillium urticae nrrl2159a, was determined by dideoxy sequencing, and the 5' end and intron-exon border of the 1-rrna gene were determined by primer extension analysis and rna sequencing, respectively. in addition to the extensive sequence homology of the 3' end of the p. urticae mt 1-rrna gene with those of aspergillus nidulans and neurospora crassa, the p. ...19957592555
a novel nitrite reductase gene from the cyanobacterium plectonema boryanum.the gene (nira) for nitrite reductase was cloned from the nonheterocystous, filamentous cyanobacterium plectonema boryanum. the predicted protein consists of 654 amino acids and has a calculated molecular weight of 72,135. the deduced amino acid sequence from positions 1 to 511 is strongly similar to the entire sequence of the ferredoxin-dependent nitrite reductases from other phototrophs, while the remainder of the protein is unique to the plectonema nitrite reductase. the c-terminal portion of ...19957592378
phanerochaete chrysosporium glyoxal oxidase is encoded by two allelic variants: structure, genomic organization, and heterologous expression of glx1 and glx2.a cdna clone (glx-2c) encoding glyoxal oxidase (glox) was isolated from a phanerochaete chrysosporium lambda gt11 library, and its nucleotide sequence was shown to be distinct from that of the previously described clone glx-1c (p. j. kersten and d. cullen, proc. natl. acad. sci. usa 90:7411-7413, 1993). genomic clones corresponding to both cdnas were also isolated and sequenced. overall nucleotide sequence identity was 98%, and the predicted proteins differed by a single residue: lys-308<==>thr- ...19957592374
a lacz reporter fusion method for the genetic analysis of regulatory mutations in pathways of fungal secondary metabolism and its application to the aspergillus nidulans penicillin pathway.secondary metabolism, usually superfluous under laboratory conditions, is intrinsically elusive to genetic analysis of its regulation. we describe here a method of analyzing regulatory mutations affecting expression of secondary metabolic genes, with an aspergillus nidulans penicillin structural gene (ipna [encoding isopenicillin n-synthase]) as a model. the method is based on a targeted double integration of a lacz fusion reporter gene in a chromosome different from that containing the penicill ...19957592369
post-transcriptional control and kinetic characterization of proline transport in germinating conidiospores of aspergillus the filamentous fungus aspergillus nidulans, l-proline uptake is mediated by the product of the prnb gene which codes for a member of a family of amino acid transporters found both in pro- and eukaryotes. regulation of prnb gene expression has previously been studied in great detail at the molecular level. however, no studies have addressed possible post-transcriptional controls or the kinetic characterisation of the prnb transporter. here we develop a rapid and efficient method for direct up ...19957590163
molecular biological analysis of a bidirectional hydrogenase from 8.9-kb segment with hydrogenase genes from the cyanobacterium anabaena variabilis has been cloned and sequenced. the sequences show homology to the methyl-viologen-reducing hydrogenases from archaebacteria and, even more striking, to the nad(+)-reducing enzymes from alcaligenes eutrophus and nocardia opaca as well as to the nadp(+)-dependent protein from desulfovibrio fructosovorans. the cluster from a. variabilis contains genes coding for both the hydrogenase heterodimer (hoxh and hoxy) and ...19957588754
design of an object-oriented database for reverse genetics.we present the design of an object-oriented database system for reverse genetics applications. such a database will encapsulate not only the data in the genetic and physical maps, but also the methods used to create the maps as well as methods to link them to other databases, such as genbank, pir, and medline. the purpose of this database is to provide the fungal genetics community with an electronic tool for identifying the biochemical function of any dna fragment in the database--electronic re ...19937584341
aspergillus fumigatus antigens.cytosolic fractions of mycelial extracts from aspergillus nidulans, a. flavus, and three different isolates of a. fumigatus, grown to stationary phase in czapek-dox-aoac medium, were tested by immunoblotting for the presence of antigens reactive to 80 serum samples from aspergilloma patients. fifty control serum samples were used to determine the specificity of the reactions. in the a. fumigatus cytosolic fraction a group of four main antigenic bands (p90, p60, p40 and p37) was consistently reco ...19957582030
does gene palb regulate the transcription or the post-translational modification of pi-repressible phosphatases of aspergillus nidulans?when grown on low-pi medium, the chaa1 pabaa1 palb7 mutant of aspergillus nidulans excretes an acid phosphatase with steady-state kinetic properties, temperature sensitivity and electrophoretic mobility different from those of the enzyme excreted by the pabaa1 strain. the enzyme excreted by the pabaa1 strain at ph 6.5 showed pnp-p activity with negative cooperativity (k0.5 = 0.87 +/- 0.06 mm, n = 0.68 +/- 0.03) whereas the enzyme excreted by the chaa1 pabaa1 palb7 mutant showed michaelian kineti ...19957581026
characterization and localization of the cytoplasmic dynein heavy chain in aspergillus nidulans.migration of nuclei throughout the mycelium is essential for the growth and differentiation of filamentous fungi. in aspergillus nidulans, the nuda gene, which is involved in nuclear migration, encodes a cytoplasmic dynein heavy chain. in this paper we use antibodies to characterize the aspergillus cytoplasmic dynein heavy chain (acdhc) and to show that the acdhc is concentrated at the growing tip of the fungal mycelium. we demonstrate that four temperature-sensitive mutations in the nuda gene r ...19957568239
fungal metabolic model for human type i hereditary tyrosinaemia.type i hereditary tyrosinaemia (ht1) is a severe human inborn disease resulting from loss of fumaryl-acetoacetate hydrolase (fah). homozygous disruption of the gene encoding fah in mice causes neonatal lethality, seriously limiting use of this animal as a model. we report here that faha, the gene encoding fah in the fungus aspergillus nidulans, encodes a polypeptide showing 47.1% identity to its human homologue, faha disruption results in secretion of succinylacetone (a diagnostic compound for h ...19957568087
the intergenic region between the divergently transcribed niia and niad genes of aspergillus nidulans contains multiple nira binding sites which act bidirectionally.the niad and niia genes of aspergillus nidulans, which code, respectively, for nitrate and nitrite reductases, are divergently transcribed, and their atgs are separated by 1,200 bp. the genes are under the control of the positively acting nira transcription factor, which mediates nitrate induction. the dna binding domain of nira was expressed as a fusion protein with the glutathione s-transferase of schistosoma japonicum. gel shift and footprint experiments have shown that in the intergenic regi ...19957565720
the aspergillus parasiticus polyketide synthase gene pksa, a homolog of aspergillus nidulans wa, is required for aflatoxin b1 biosynthesis.aflatoxins comprise a group of polyketide-derived carcinogenic mycotoxins produced by aspergillus parasiticus and aspergillus flavus. by transformation with a disruption construct, pxx, we disrupted the aflatoxin pathway in a. parasiticus srrc 2043, resulting in the inability of this strain to produce aflatoxin intermediates as well as a major yellow pigment in the transformants. the disruption was attributed to a single-crossover, homologous integration event between pxx and the recipient a. pa ...19957565588
a pre-induction sporulation gene from aspergillus nidulans.asexual sporulation in aspergillus nidulans is an inducible developmental process controlled by genes that act before and after the inductive stimulus is applied. genes that act before induction (pre-induction genes) potentially represent functions required for response to induction. this report describes the isolation and characterization of the acob pre-induction gene which was cloned by complementation of a thermosensitive aconidial mutant followed by gene rescue. genetic analysis and gene di ...19957551046
cloning and nucleotide sequence of the calmodulin-encoding gene (cmda) from aspergillus oryzae.a cdna and genomic gene encoding calmodulin were isolated from aspergillus oryzae using a part of the calmodulin gene from a. nidulans as a hybridization probe. the gene was in a 3.4-kb sphi fragment and southern-blot analysis of genomic dna suggested the existence of a single copy of the calmodulin gene in a. oryzae. the nucleotide sequence analysis showed that the gene consists of five introns and six exons. although the nucleotide sequence homology with that of a. nidulans was not so high (68 ...19957549095
analysis of a mycotoxin gene cluster in aspergillus nidulans.aspergillus nidulans has functioned as a model system for the study of fungal genetics since the 1950s. application of methodologies ranging from mendelian genetics to the most sophisticated molecular biological techniques have resulted in a detailed understanding of genes and pathways involved in primary metabolism, secondary metabolism and development in a. nidulans. we have taken advantage of this background in developing a. nidulans as a genetic system to study the molecular mechanisms regul ...19957546572
copper-induced changes in the urea uptake and urease activity in the cyanobacteria anabaena doliolum and anacystis nidulans: interaction with sulphur containing amino acids.copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria anabaena doliolum and anacystis nidulans. copper, at and above 5 mumol/l concentration, inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner. however, the urea uptake and urease activity systems in a. nidulans appeared slightly more tolerant to copper than than of a. doliolum. the inhibitory effect of copper on urea uptake and urease ...19957546344
salt sensitivity and arginine toxicity in aspergillus nidulans. 19957538946
based on biochemical and physiological behavior, where is aspergillus egyptiacus better placed?physiological and biochemical properties were tested in 45 isolates of aspergillus egyptiacus (16 isolates), emericella nidulans (16) and aspergillus versicolor (13). the three fungal species exhibited common and similar features. the big similarity between a. egyptiacus and e. nidulans was greater than between a. egyptiacus and a. versicolor. it included the inability to produce base either from sodium citrate or lactic acid media, growth at 45 degrees c (thermophilicity), and production of ver ...19947537240
nitrite reductase gene cloning of amycolatopsis mediterranei u-32.southern blot analysis showed great homology existed between niad (nr gene) of aspergillus nidulans and a. mediterranei u-32 chromosome dna. a 5.0kb psti fragment from a. mediterranei u-32 complementary to a. nidulans niad gene was cloned in e. coli nm522 using niad as a probe. an identical dna band was observed through back-hybridization of the cloned dna fragment to psti digest of a. mediterranei u-32 chromosome dna. its 2.1 kb smai-ecorv fragment can only hybridize with total rna from nitrate ...19947534488
molecular and cellular parameters controlling the immunogenicity of foreign b- or t-cell epitopes expressed by recombinant vectors.extensive work is being performed to develop live recombinant bacterial vaccines. the use of non-pathogenic bacteria or attenuated strains derived from pathogens may allow protection against the pathogen and at the same time induce immunity against one or several foreign antigens expressed by the recombinant micro-organism. several bacteria such as attenuated salmonella or bcg have been used successfully in several experimental models to induce protective immune responses against several pathoge ...19947525391
cell cycle-dependent expression of nek2, a novel human protein kinase related to the nima mitotic regulator of aspergillus nidulans.the serine/threonine protein kinase nima of aspergillus nidulans is required for entry into mitosis and may function in parallel to the universal mitotic inducer p34cdc2. here, we report the isolation of complementary dnas encoding nek2 and nek3, two novel human protein kinases structurally related to nima. sequence comparisons revealed several unique features which may define a family of nima-related protein kinases. nek2 was chosen for further study since it represents the closest known mammal ...19947522034
mycoflora of post-harvest maize and wheat grains and the implication of their contamination by molds.thirteen fungi including toxigenic aspergillus nidulans and a. clavatus were isolated from the grains. the isolated fungi grew well at 25-30 degrees c. a. clavatus and a. nidulans were grown in liquid maize yeast extract medium and wheat yeast extract medium. both fungi produced amylases on the two media and on the basal medium at 30 degrees c. during incubation more total reducing sugars were detected in maize grains than in wheat while non-reducing sugars were detected than reducing sugars in ...19947518052
a test for uniparental disomy in saccharomyces cerevisiae.uniparental disomy is a condition in a diploid organisms where one parental chromosome is absent and its homolog from the other parent duplicated. it can be a cause of genetic somatic disease in mammals because of imprinting. imprinting creates a sex-specific pattern of epigenetic gene inactivation at least in mammals and, consequently, a complete set of both maternal and paternal chromosomes is required for normal development. moreover, it has been shown for several types of tumors that recessi ...19947512218
the genetic activity of 6-n-hydroxylaminopurine in aspergillus nidulans.the activity of a base analog (6-n-hydroxylaminopurine, hap) has been tested on aspergillus nidulans. in germinating haploid conidia hap is a strong mutagen, while it does not have any activity in resting conidia. moreover, hap does not increase the frequency of recombination in germinating conidia. the mutagenic activity of this base analog has also been tested in diploid conidia of a. nidulans; in fact, it has been shown (pavlov et al., 1991) that the hap-induced frequency of heteroallelic rec ...19947510841
genotoxic activity of mebendazole in aspergillus nidulans.mebendazole is an anthelmintic drug widely used in cuba and in mexico. its interaction with tubulin interferes with the assemblage of the mitotic apparatus in the parasite cells, thus suggesting a possible genotoxic activity leading to chromosomal malsegregation. the heterozygous diploid strain d30 of aspergillus nidulans was used to establish the ability of mebendazole to induce mitotic recombination and/or chromosomal non-disjunction, and the haploid strain fgsc #219 of a. nidulans was used to ...19947510023
metabolism of folate glutamates in aspergillus nidulans. 19937508173
mitotic catastrophe is the mechanism of lethality for mutations that confer mutagen sensitivity in aspergillus nidulans.we have examined the consequences of treatment with dna-damaging agents of uvs mutants and the bimd6 mutant of aspergillus nidulans. we first established that wild-type aspergillus undergoes a cell cycle delay following treatment with the dna-damaging agents methyl methanesulfonate (mms) or ultraviolet light (uv). we have also determined that strains carrying the bimd6, uvsb110, uvsh77, uvsf201 and the uvsc114 mutations, all of which cause an increased sensitivity to dna-damaging agents, undergo ...19947506362
two group i introns with a c.g basepair at the 5' splice-site instead of the very highly conserved u.g basepair: is selection post-translational?in virtually all of the 200 group i introns sequenced thus far, the specificity of 5' splice-site cleavage is determined by a basepair between a uracil base at the end of the 5' exon and a guanine in an intron guide sequence which pairs with the nucleotides flanking the splice-site. it has been reported that two introns in the cytochrome oxidase subunit i gene of aspergillus nidulans and podospora anserina are exceptions to this rule and have a c.g basepair in this position. we have confirmed th ...19957501471
structural analysis of pks1, a polyketide synthase gene involved in melanin biosynthesis in colletotrichum lagenarium.albino mutants (pks-) of colletotrichum lagenarium form nonmelanized appressoria and possess little penetrating ability on the host plant. the defect in albino mutant 79215 (pks-) is considered to lie in pentaketide biosynthesis and/or pentaketide cyclization during melanin biosynthesis. the cosmid pac7, carrying the pks1 gene, when transformed into the albino mutant restores the wild-type melanin phenotype. we have determine the dna sequence and the transcriptional organization of the pks1 gene ...19957500937
signaling of ambient ph in aspergillus involves a cysteine aspergillus nidulans, the regulation of gene expression in response to changes in ambient ph is mediated by the pacc zinc finger transcriptional regulator. at alkaline ambient ph, pacc is proteolytically processed to a functional form serving as an activator of alkaline-expressed genes and a repressor of acid-expressed genes. this activation of pacc occurs in response to a signal mediated by the products of the pal genes. thus, the products of the pala, -b, -c, -f, -h, and -i genes constitute ...19957499363
monoclonal antibodies against a 97-kilodalton antigen from aspergillus flavus.we prepared a panel of five monoclonal antibodies (mabs) directed against aspergillus flavus that all reacted against one 97-kda antigen by western blot (immunoblot). flow cytometry demonstrated that these antibodies bound (in increasing degrees) to all morphologic stages of a. flavus growth: conidia, swollen conidia, and hyphae. cross-reactivity among species was examined by enzyme-linked immunosorbent assay of fungal culture filtrates. four mabs reacted with 10 of 11 a. flavus isolates, and th ...19947496924
an extreme crea mutation in aspergillus nidulans has severe effects on d-glucose utilization.aspergillus nidulans wild-type and the extreme carbon catabolite derepressed mutant cread-30 were characterized with respect to enzyme activities, metabolite concentrations and polyol pools all related to glycolysis, after growth on d-glucose. in the cread-30 strain the enzymes hexokinase and fructose-6-phosphate reductase showed a two- and threefold increase in activity, respectively, whereas phosphofructokinase and pyruvate kinase activity decreased two- and threefold, respectively, in compari ...19957496542
substrate specificity of nine nad(+)-dependent alcohol dehydrogenases in aspergillus aspergillus nidulans three alcohol dehydrogenases (adhs) have been described. adhi is induced by ethanol and is the physiological enzyme of ethanol utilization, adhii has not been attributed a function but is repressed by ethanol. the alcr regulatory protein acts positively to induce adhi, and negatively in its control of adhii. adhiii is specifically induced by anaerobic stress. we have characterized the substrate specificity of these three enzymes by looking at their staining profile on pol ...19957496541
insertion into aspergillus nidulans of functional udp-glcnac: alpha 3-d- mannoside beta-1,2-n-acetylglucosaminyl-transferase i, the enzyme catalysing the first committed step from oligomannose to hybrid and complex n-glycans.filamentous fungi are capable of secreting relatively large amounts of heterologous recombinant proteins. recombinant human glycoproteins expressed in this system, however, carry only carbohydrates of the oligomannose type limiting their potential use in humans. one approach to the problem is genetic engineering of the fungal host to permit production of complex and hybrid n-glycans. udp-glcnac:alpha 3-d-mannoside beta- 1,2-n-acetylglucosaminyltransferase i (gnt i) is essential for the conversio ...19957496151
sepb: an aspergillus nidulans gene involved in chromosome segregation and the initiation of aspergillus nidulans conidia, cytokinesis (septation) is delayed until three rounds of nuclear division have been completed. this has permitted the identification of essential genes that are involved in the coordination of cytokinesis with nuclear division. conditional mutations in the sepb gene block septation but allow germinating spores to complete the first three rounds of nuclear division at restrictive temperature. sepb3 mutants demonstrate transient delays in m-phase, accumulate aneupl ...19957489714
stcs, a putative p-450 monooxygenase, is required for the conversion of versicolorin a to sterigmatocystin in aspergillus nidulans.sterigmatocystin (st) and aflatoxin are carcinogenic end point metabolites derived from the same biochemical pathway, which is found in several aspergillus spp. recently, an st gene cluster, containing approximately 25 distinct genes that are each proposed to function specifically in st biosynthesis, has been identified in aspergillus nidulans. each of these structural genes is named stc (sterigmatocystin) followed by a consecutive letter of the alphabet. we have previously described stcu (forme ...19957486998
the bgl1 gene of trichoderma reesei qm 9414 encodes an extracellular, cellulose-inducible beta-glucosidase involved in cellulase induction by sophorose.we have investigated the effect of disruption of the bgl1-(beta-glucosidase l-encoding) gene of trichoderma reesei on the formation of other beta-glucosidase activities and on the induction of cellulases. to this end the bgl1 locus was disrupted by insertion of the aspergillus nidulans amds (acetamidase-encoding) gene. the bgl1-disrupted strain did not produce the 75 kda extracellular beta-glucosidase on cellulose or lactose, but still formed beta-glucosidase activity on glucose, cellobiose, xyl ...19957476163
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
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 in which o-acetylhomoserine is an acceptor of the methylthio group. the first step on the salvage pathway of t ...19827052140
molecular and genetic methods for studying mitosis and spindle proteins in aspergillus nidulans. 19827050618
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
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
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
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 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
genetical and biochemical aspects of quinate breakdown in the filamentous fungus aspergillus 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
[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
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
purification and characterization of the assimilatory nadph-nitrate reductase of aspergillus nidulans.nadph-nitrate reductase [nadph : nitrate oxidoreductase, ec] 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
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
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
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
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
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
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
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
testing for mitotic crossing over and induced aneuploidy using aspergillus nidulans as part of the ukems test programme. 19827035881
aspergillus nidulans as a test organism for chemical 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
a method for the selection of deletion mutations in the l-proline catabolism gene cluster of aspergillus nidulans. 19817035292
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
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
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
[otomycosis in the south of chile]. 19817034110
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
the regulation of phosphoenolpyruvate carboxykinase and the nadp-linked malic enzyme in aspergillus has previously been suggested that the synthesis of phosphoenolpyruvate carboxykinase (ec 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
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
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
mutagenicity of pesticides evaluated by means of gene-conversion in saccharomyces cerevisiae and in aspergillus nidulans.nine pesticides, afugan, atrazine, benomyl, captan, daconil, melthaumittel, plantvax, saprol, and wepsin were tested for the induction of mitotic gene-conversion in two different eucaryotic microorganisms, saccharomyces cerevisae and aspergillus nidulans. in s cerevisiae the pesticides were also tested after mouse liver microsomal activation; in a nidulans all tests were performed using both resting and germinating conidia. among the tested pesticides, only captan revealed a consistent genetic a ...19807032901
sensitive detection of tritium in southern blot and plaque hybridizations. 19817032353
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
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
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
mutagenicity of monoadducts and cross-links induced in aspergillus nidulans by 8-methoxypsoralen plus 365 nm radiation. 19817027284
evolution of rrna and origin of mitochondria. 19817027053
thiram-induced abnormal chromosome segregation in aspergillus nidulans. 19817027033
mutagenicity of chemicals of industry and agricultural relevance in salmonella, streptomyces and aspergillus. 19817026896
fatty acid composition of oil synthesized by aspergillus nidulans.the filamentous fungus aspergillus nidulans eidam strain 300 was found to be capable of synthesizing 24.9% oil or remarkably low free fatty acidity, in a chemically defined medium with 34% glucose as sole carbon source. although the total content of oil synthesized was less, utilization of the carbon source is better as shown by the high (8.4) fat coefficient. the major component fatty acids of the oil were palmitic, stearic, oleic and linoleic and are influenced by the source of carbon. palmito ...19817026394
pyruvate carboxylase from aspergillus nidulans. regulatory properties. 19817026241
lipid components variation among the temperature-sensitive mutants and wild strain of aspergillus nidulans.the fungus aspergillus nidulans and its two temperature-sensitive mutants were grown in synthetic media at permissive and restrictive temperatures. after seven days of growth, total lipids were extracted and characterised from the mycelia. in the case of the wild strain, an increase in the incubation temperature resulted in an increase in the ratio of unsaturated to saturated fatty acids and was inversely proportional to the ratio of short chain to long chain fatty acids. it was interesting to n ...19817021468
induction of extracellular proteases by egg-white in aspergillus nidulans.aspergillus nidulans when supplemented with egg-white protein (1 %) produced considerable amounts of proteases extracellularly. the order of the appearance of the proteolytic enzymes growth on untreated and heat-inactivated egg-white were studied. they showed ph optima of 5, 7.2 and 9 when assayed at 37 degrees c. it is proposed that one of the factors leading to higher cell mass of a. nidulans in the presence of egg-white is the availability of protease-catalyzed hydrolyzed products of egg-whit ...19817021371
an alpha-amanitin-resistant dna-dependent rna polymerase ii from the fungus aspergillus alpha-amanitin-resistant dna-dependent rna polymerase ii has been purified from the lower eukaryote aspergillus nidulans to apparent homogeneity by extraction of the enzyme at low salt concentration, polymin p (polyethylene imine) fractionation, binding to ion-exchangers and density gradient centrifugation. by this procedure 0.4 mg of rna polymerase ii can be purified over 6,000-fold from 500 g (wet weight) of starting material with a yield of 25% and a specific activity of 550 units/mg. the ...19817021153
induction of point mutations by benomyl in dna-repair-deficient aspergillus nidulans. 19817019695
genetics of penicillin titre in lines of aspergillus nidulans selected through recurrent mutagenesis.genetic analyses of mutations for increased penicillin titre were carried out on two strains of aspergillus nidulans isolated after independent programmes of recurrent mutation and selection, similar to those used industrially for strain improvement. both selected strains were stable in terms of colony morphology and penicillins titre. backcrosses to the unselected ancestor indicated that the increased yield of each strain was due to an induced polygenic system with both additive and non-additiv ...19807019390
genetic evidence for a second asparaginase in aspergillus nidulans.the apna1 mutation strongly reduces l-asparagine utilization in aspergillus nidulans. the ahra1 mutation, leading to loss of an l-asparaginase (drainas et al., 1977), eliminates residual l-asparagine utilization in double mutant strains also carrying apna1. this additivity suggests that a. nidulans, like saccharomyces cerevisiae (jones, 1977; dunlop et al., 1978), has two l-asparaginases specified by apna and ahr a, respectively, apna has been mapped to a position on the left arm of linkage grou ...19807019388
a beta-tubulin mutation in aspergillus nidulans that blocks microtubule function without blocking assembly.we have isolated a heat-sensitive beta-tubulin mutation, bena33, that blocks nuclear division and nuclear movement at restrictive temperature. this blockage demonstrates that the beta tubulin encoded by the bena gene is essential to both processes. the blockage of both processes is suppressed by the alpha-tubulin mutation, tuba1; thus the alpha tubulin encoded by the tuba gene must also be involved in both processes. when bena33 is shifted from a permissive to restrictive temperature, nuclei are ...19817018696
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
Displaying items 3601 - 3700 of 5149