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purification and characterization of two extracellular beta-glucosidases from aspergillus nidulans.two beta-glucosidases, p-i and p-ii, were purified from the culture filtrate of aspergillus nidulans. the m(r) values of p-i and p-ii were about 125,000 and 50,000, respectively. the isoelectric point, optimal ph and temperature, michaelis constants for several substrates and inhibition constants for glucose and glucono-delta-lactone of each enzyme were determined. we conclude that the high affinity toward cellobiose and low inhibition by glucose of these enzymes may offer significant advantages ...19921426998
the use of simulated annealing in chromosome reconstruction experiments based on binary scoring.we present a method of combinatorial optimization, simulated annealing, to order clones in a library with respect to their position along a chromosome. this ordering method relies on scoring each clone for the presence or absence of specific target sequences, thereby assigning a digital signature to each clone. specifically, we consider the hybridization of oligonucleotide probes to a clone to constitute the signature. in that the degree of clonal overlap is reflected in the similarity of their ...19921427046
selective expression of a major allergen and cytotoxin, asp f i, in aspergillus fumigatus. implications for the immunopathogenesis of aspergillus-related diseases.asp f i is a major 18-kda aspergillus fumigatus allergen and a member of the mitogillin family of cytotoxins. the nucleotide sequence of the asp f i gene was determined by sequencing polymerase chain reaction products amplified from a. fumigatus spore dna. the entire 678-bp dna includes an 81-bp leader sequence, preceding the n-terminal alanine codon, a 52-bp intron, and a 444-bp open reading frame, encoding a 149-amino acid protein (m(r) 16,899), which is 99% homologous to mitogillin from asper ...19921431110
analysis of the site of action of the amdr product for regulation of the amds gene of aspergillus nidulans.the amdr gene of aspergillus nidulans regulates a number of structural genes in response to omega amino acid inducers. the site of action of the amdr product on expression of the amds gene was investigated by studying the effects of changes in the 5' region of amds, generated in vitro, on the induction, and on responses of an amds-lacz fusion gene to an amdrc allele. a sequence was identified that is sufficient for amdr regulation and that shows identity with sequences involved in amdr regulatio ...19921435733
prediction of transmembrane topology of f0 proteins from escherichia coli f1f0 atp synthase using variational and hydrophobic moment analyses.the a subunit, a membrane protein from the e. coli f1f0 atp synthase has been examined by fourier analysis of hydrophobicity and of amino-acid residue variation. the amino-acid sequences of homologous subunits from vibrio alginolyticus, saccharomyces cerevisiae, neurospora crassa, aspergillus nidulans, schizosaccharomyces pombe and candida parapsilosis were used in the variability analysis. by fourier analysis of sequence variation, two transmembrane helices are predicted to have one face in con ...19921445940
structural and functional analysis of the amdr regulatory gene of aspergillus oryzae.we have isolated the aspergillus oryzae homologue of the amdr regulatory gene of aspergillus nidulans by cross hybridization. sequence analysis and functional studies have shown that the amdr genes are highly conserved and functionally interchangeable between the two species. the homology between the two genes extends throughout most of the coding sequences, including sequences encoding the dna-binding domain and putative activation domains. two regions of nonconserved sequence were also identif ...19921452021
an inducible expression system for the production of human lactoferrin in aspergillus nidulans.the production and secretion of human lactoferrin (hlf) in aspergillus nidulans is described. the hlf cdna was expressed under the control of the strong ethanol-inducible alcohol dehydrogenase (alca) promoter. recombinant hlf (re-hlf) is produced at levels up to 5 micrograms/ml. approximately 30% of the re-hlf produced in this system is secreted into the growth medium. the re-hlf is indistinguishable from native hlf with respect to size and immunoreactivity. furthermore, re-hlf is functional by ...19921452033
cloning and molecular characterization of the glyceraldehyde-3-phosphate dehydrogenase-encoding gene and cdna from the plant pathogenic fungus glomerella cingulata.the glyceraldehyde-3-phosphate dehydrogenase gene (gpda) has been identified from a genomic dna library prepared from the plant pathogenic fungus glomerella cingulata. nucleotide sequence data revealed that this gene codes for a putative 338-amino-acid protein encoded by two exons of 129 and 885 bp, separated by an intron 216 bp long. the 5' leader sequence is also spliced by an intron of 156 bp. a cdna clone was prepared using the polymerase chain reaction, the sequence of which was used to con ...19921452034
purification, properties and primary structure of thioredoxin from aspergillus nidulans.this paper reports the purification and the properties of a thioredoxin from the fungus aspergillus nidulans. this thioredoxin is an acidic protein which exhibits an unusual fluorescence emission spectrum, characterized by a high contribution of tyrosine residues. thioredoxin from a. nidulans cannot serve as a substrate for escherichia coli thioredoxin reductase. corn nadp-malate dehydrogenase is activated by this thioredoxin in the presence of dithiothreitol, while fructose-1,6-bisphosphatase i ...19921459127
developmental and light regulation of eas, the structural gene for the rodlet protein of neurospora.the surface of many fungal spores is covered by a hydrophobic sheath termed the rodlet layer. we have determined that the rodlet protein of neurospora crassa is encoded by a cloned gene designated bli-7, and that bli-7 is identical to the known gene eas (easily wettable). using eas dna as a probe we show that eas mrna is abundant in illuminated mycelia and conidiophores but is not detectable or is barely detectable in dark-grown mycelia, mature macroconidia, microconidia, and ascospores. mutatio ...19921459459
the developmentally regulated aspergillus nidulans wa gene encodes a polypeptide homologous to polyketide and fatty acid synthases.the aspergillus nidulans wa gene is required for synthesis of a green pigment present in the walls of mature asexual spores (conidia); wa mutants produce colorless (white) conidia. we determined the transcriptional structure and dna sequence of the wa gene. wa consists of 5 exons separated by short (40-60 bp) introns. the processed transcript has the potential to encode a protein consisting of 1986 amino acid residues. the predicted wa polypeptide showed extensive sequence similarities with bact ...19921465094
characterization of the amda-regulated acia gene of aspergillus nidulans.the structure, function and regulation of the acetate inducible acia gene of aspergillus nidulans was analysed. the acia locus was mapped to chromosome 1 at a position where no acetate inducible gene has been previously located. the nucleotide sequence of acia was determined, the structures of two transcripts were determined and the sequences of the polypeptide products of the gene were deduced. construction of an acia loss-of-function mutant was achieved via insertional inactivation, but it did ...19921465107
identification of functional regions of the positively acting regulatory gene amdr from aspergillus nidulans.the amdr (inta) regulatory gene of aspergillus nidulans encodes a 765-amino-acid polypeptide which determines the omega-amino acid induction of at least five structural genes. the amdr polypeptide contains a potential zn(ii)2cys6 dna-binding motif which has been shown to be present in the n-terminal region of a large number of fungal activator proteins. in vitro mutagenesis of the fourth cysteine of this motif abolishes amdr function as shown by loss of complementation of an amdr- mutation and b ...19921479891
mitotic regulation in aspergillus nidulans.the nima and bime genes of aspergillus nidulans respectively encode a 79 kda protein kinase that is a positive regulator of mitosis and a 229 kda protein that is a negative regulator of mitosis. either overproduction of nima or inactivation of bime can induce mitosis and override the checkpoint associated with incomplete dna replication. double mutants between temperature-sensitive nima and bime alleles undergo chromatin condensation and spindle polymerization at restrictive temperature, suggest ...19921483343
isolation of an aspergillus terreus mutant impaired in arginine biosynthesis and its complementation with the argb gene from aspergillus nidulans.using filtration enrichment techniques, an aspergillus terreus arginine auxotrophic strain which contains a mutation that abolishes ornithine transcarbamylase (otcase) activity has been isolated. this mutant has been genetically transformed with the cloned aspergillus nidulans otcase gene. prototrophic transformants arose at a frequency of about 50 transformants per microgram of plasmid dna. southern blot analysis of dna from the transformants showed that the transforming dna was ectopically int ...19921490598
requirement for esp1 in the nuclear division of saccharomyces cerevisiae.mutations in the esp1 gene of saccharomyces cerevisiae disrupt normal cell-cycle control and cause many cells in a mutant population to accumulate extra spindle pole bodies. to determine the stage at which the esp1 gene product becomes essential for normal cell-cycle progression, synchronous cultures of esp1 mutant cells were exposed to the nonpermissive temperature for various periods of time. the mutant cells retained viability until the onset of mitosis, when their viability dropped markedly. ...19921493337
a dominant selectable marker that is meiotically stable in neurospora crassa: the amds gene of aspergillus nidulans.when neurospora crassa is transformed using a neurospora gene as the selectable marker, the vegetatively stable transformants obtained cannot be used successfully in a cross because the selectable marker will be inactivated by the process of rip (repeat-induced point mutation). introduction of the acetamidase-encoding gene amds of aspergillus nidulans into n. crassa by transformation yielded transformants that would grow in minimal medium containing acetamide as a sole nitrogen source. in mitoti ...19921494342
characterization of the aspergillus niger pelb gene: structure and regulation of expression.the nucleotide sequence of pelb, a member of the aspergillus niger pectin lyase multigene family, has been determined. the pelb gene product, plb, shares 65% amino acid identity with pectin lyase a (pla) and 60% with pectin lyase d (pld). although growth of pelb multicopy transformants on pectin-containing media results in elevated pelb mrna levels, pectin lyase b (plb) is barely detectable. this is probably due to degradation of plb by acid proteases, since multicopy transformants grown on pect ...19921495474
npk1, a nonessential protein kinase gene in saccharomyces cerevisiae with similarity to aspergillus nidulans nima.a new protein kinase gene [called npk1 (for nonessential protein kinase)] has been found on chromosome i of saccharomyces cerevisiae between cdc15 and ade1. the 435 amino acid/48 kda gene product is very similar to known protein kinases. it is most closely related to the nima protein of aspergillus nidulans, displaying 45.9% identity and 63.5% similarity in the protein kinase domain. a 1.4 kb transcript of the npk1 gene was detected. disruption of the npk1 gene impedes neither growth on glucose ...19921495480
arginine and proline genes of aspergillus niger.aspergillus niger mutants defective in arginine or proline biosynthesis have been isolated and 12 genetic loci were identified. mutation was induced by low doses uv, and mutants were isolated after filtration enrichment. the mutants were classified according to their phenotype in growth tests and were further characterized in complementation tests. the arginine auxotrophic mutants represent nine complementation groups. three additional complementation groups were found for mutants that could gro ...19921497330
early developmental events during asexual and sexual sporulation in aspergillus nidulans. 19921504597
control of gene expression in the catabolic pathways of aspergillus nidulans: a personal and biased account. 19921504607
protein synthesis in aspergillus nidulans.in this review of protein synthesis, we have described a system for translation of mrna using extracts of a. nidulans. this system is useful for characterizing mutants suspected to have defects in protein synthesis and for assessing the toxicity of various antibiotics and their effects on misreading the genetic code. the well developed genetical system of a. nidulans has enabled us to map at least 27 new genes whose mutation disturbs the level of translational accuracy. these mutants could be us ...19921504608
mutational analysis of calmodulin in saccharomyces cerevisiae.calmodulin is well characterized as an intracellular ca2+ receptor in nonproliferating tissues such as muscle and brain. several observations indicate that calmodulin is also required for cellular growth and division. deletion of the calmodulin gene is a lethal mutation in saccharomyces cerevisiae, schizosaccharomyces pombe and aspergillus nidulans. expression of calmodulin antisense rna in mouse c127 cells causes a transient arrest at g1 and metaphase. although these results indicate calmodulin ...19921505005
isolation of a gene required for programmed initiation of development by aspergillus nidulans.in contrast to many other cases in microbial development, aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation. mutations in the acod locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. we show that unlike wild-type strains, acod deletion mutants are unable to make conidiophores under optimal growth condit ...19921508186
the polygalacturonases of aspergillus niger are encoded by a family of diverged genes.aspergillus niger produces several polygalacturonases that, with other enzymes, are involved in the degradation of pectin. one of the two previously characterized genes coding for the abundant polygalacturonases i and ii (pgi and pgii) found in a commercial pectinase preparation was used as a probe to isolate five more genes by screening a genomic dna library in phage lambda embl4 using conditions of moderate stringency. the products of these genes were detected in the culture medium of aspergil ...19921511691
effect of restrictive conditions on the growth and morphology of a temperature-sensitive mannose-requiring mutant of aspergillus nidulans.when incubated at 45 degrees c in the absence of added mannose, pregrown hyphae of a temperature-sensitive, mannose-relief mutant (mnra455) of aspergillus nidulans grew normally for a short time (4-5 h) before exhibiting an abnormal morphology consisting of the production by hyphae of discrete spherical swellings called balloons. these swellings could be up to 10 microns in diameter and were produced either at or behind the hyphal apex. often only one swelling was produced in association with ea ...19921516805
stua is required for cell pattern formation in aspergillus.the stunted (stua) gene product is required for the orderly differentiation and spatial organization of cell types of the aspergillus nidulans conidiophore. expression of the stua gene is complex. two transcripts, stua alpha and stua beta, are initiated from separate promoters. transcription of both rnas increases approximately 50-fold during the establishment of developmental competence. induction-dependent transcriptional and post-transcriptional regulatory mechanisms further enhance expressio ...19921516832
chromatin structure of schizosaccharomyces pombe. a nucleosome repeat length that is shorter than the chromatosomal dna length.we have used new methods for chromatin isolation, together with conventional methods for measuring the nucleosome repeat length, to determine the repeat length of schizosaccharomyces pombe chromatin. we obtain a result of 156(+/- 2) bp. equivalent results are obtained using a psoralen crosslinking method for measuring the repeat length in viable spheroplasts. that result, together with other control experiments, rules out many possible artifacts. the measured value of 156(+/- 2) bp is smaller th ...19921518041
phase i study of yk-176 (2'-deoxycoformycin) in patients with adult t-cell leukemia-lymphoma. the dcf study group.yk-176 is a newly isolated 2'-deoxycoformycin (dcf), a potent inhibitor of adenosine deaminase, produced by aspergillus nidulans. in a cooperative phase i study, yk-176 was administered to 22 patients, comprising 18 with adult t-cell leukemia-lymphoma (atl), two with cutaneous t-cell lymphoma (ctcl), one with lymphoblastic lymphoma of t-cell type and one with carcinoma of the uterine cervix. doses of yk-176 ranged from 3.0 to 9.0 mg/m2 and were given intravenously for three consecutive days. gen ...19921518164
protein structure of pig liver 4-aminobutyrate aminotransferase and comparison with a cdna-deduced sequence.the amino acid sequence of pig liver 4-aminobutyrate aminotransferase has been determined by gas-phase sequencing of proteolytically derived peptide fragments. the sequence differs substantially from that predicted for the same enzyme on the basis of the sequence of cdna derived from pig brain in recently published work [kwon, o., park, j. & churchich, j. e. (1992) j. biol. chem. 267, 7215-7216]. apart from a few minor differences, the two sequences are completely different in the segment of pro ...19921521531
isolation and characterization of an analogue-resistant aminoacyl-trna synthetase mutant in aspergillus nidulans.six mutants resistant to p-fluorophenylalanine (fpa) were selected on a medium containing aspartate as the sole source of nitrogen using a phenylalanine-requiring (phena)auxotroph of a. nidulans as the wild type. the mutants, on the basis of genetic characterization, were found to be alleilic and located on the left arm of the linkage group iii, approximately 13 map unit left to meth h locus, henceforth assigned to the symbol fpav. at a fixed concentration of phenylalanine (23 micrograms/ml), th ...19921521872
[influence of heavy metal ions on the electrophysical properties of anacystis nidulans and escherichia coli cells].the influence of heavy metal ions (ag+, cu2+, cd2+, pb2+, mn2+, zn2+, gd3+, 1 microm-1 mm) on anacystis nidulans and escherichia coli cells has been studied by means of electrophoresis and electro-orientation spectroscopy methods. it has been shown that changes of cell electrophoretic mobility (em) and low-frequency (20 hz) electro-orientation effect (eoe) observed with the increase of metal cation concentration characterize the adsorption of these ions on surface layers of cell envelopes. the d ...19921522819
binding selectivity of rhizoxin, phomopsin a, vinblastine, and ansamitocin p-3 to fungal tubulins: differential interactions of these antimitotic agents with brain and fungal tubulins.the binding of four potent antimitotic agents, rhizoxin (rzx), phomopsin a (pms-a), ansamitocin p-3 (asmp-3), and vinblastine (vlb), to tubulins from rzx-sensitive and -resistant strains of aspergillus nidulans, schizosaccharomyces pombe, and saccharomyces cerevisiae was investigated. mycelial extracts to which rzx could bind contained beta-tubulin with asn as the 100th amino acid residue (asn-100) in all cases, and those without affinity for rzx contained beta-tubulins with either ile-100 or va ...19921530630
characterization of the glyoxysomal isocitrate lyase genes of aspergillus nidulans (acud) and neurospora crassa (acu-3).the nucleotide sequences of the genes encoding the acetate-inducible glyoxylate cycle enzyme isocitrate lyase from the ascomycete fungi aspergillus nidulans (acud) and neurospora crassa (acu-3) are presented. the respective a. nidulans and n. crassa genes are interrupted at identical positions by two introns and encode proteins of 538 and 543 amino acids, which have 75% identity. the predicted protein sequences do not demonstrate the c-terminal tripeptide s-k-l that has been implicated in peroxi ...19921531185
starch digestion and adsorption by beta-amylase of emericella nidulans (aspergillus nidulans).a mutant strain of emericella nidulans mnu 82 was isolated by multistep mutation. the beta-amylase produced by the mutant was able to digest raw starch. it was readily and strongly adsorbed onto raw starch at ph 5.0. the enzyme to starch ratio was 1950 u/g starch. the enzyme showed no correlation between the capacity of raw starch digestion and adsorption of the enzyme.19921533208
an extra copy of nimecyclinb elevates pre-mpf levels and partially suppresses mutation of nimtcdc25 in aspergillus nidulans.previous work has shown that nima encodes a cell cycle regulated protein kinase that is required along with the p34cdc2 histone h1 kinase (mpf) for mitosis in aspergillus nidulans. we have now identified two other gene products required for mitosis in a.nidulans. nimt encodes a protein similar to the fission yeast cdc25 tyrosine phosphatase and is required for the conversion of pre-mpf to mpf and nime encodes a b-type cyclin which is a subunit of mpf. a new genetic interaction between nimecyclin ...19921534750
nitrate reductase and nitrite reductase transcript levels in various mutants of aspergillus nidulans: confirmation of autogenous regulation.the regulation of the expression of the a. nidulans niia and niad genes (encoding nitrite reductase and nitrate reductase activities, respectively) was investigated by northern blotting. it was demonstrated that expression of the niia and niad genes is controlled at the level of mrna accumulation and that mutations within the nira and area regulatory genes, as well as certain mutations within niad itself or cnxe (for its molybdenum cofactor), markedly affect niia and niad transcript levels.19921538701
kinesin-related cut7 protein associates with mitotic and meiotic spindles in fission yeast.several mitotic and meiotic gene products are related to the microtubule motor kinesin, providing insight into the molecular basis of the complex motile events responsible for spindle formation and function. of these genes, three have been shown to affect spindle structure when mutated. the most severe phenotype is seen in aspergillus nidulans bimc and schizosaccharomyces pombe cut7 mutants. in both fungi the intranuclear spindle is bipolar, with microtubules that emanate from spindle pole bodie ...19921538784
gamma-tubulin is a centrosomal protein required for cell cycle-dependent microtubule nucleation.gamma-tubulin is a newly identified member of the tubulin family whose sequence is highly conserved from yeast to man. this minor microtubule protein is localized to the microtubule organizing centres and a mutation in the gene encoding it produces a microtubuleless mitotic arrest in the filamentous fungus aspergillus nidulans. here we investigate the in vivo function of gamma-tubulin in mammalian cells using a synthetic peptide to generate a polyclonal antibody that binds to a highly conserved ...19921538786
the aspergillus niger niad gene encoding nitrate reductase: upstream nucleotide and amino acid sequence comparisons.the aspergillus niger niad gene has been sequenced and the inferred nitrate reductase (nr) protein found to consist of 867 amino acid residues (97 kda). the gene is interrupted by six small introns, as deduced by comparison with the niad gene of aspergillus nidulans. the positions of these putative introns are conserved between the two fungi, although the sequences are dissimilar. the niia gene, encoding nitrite reductase, the second reductive step in the nitrate assimilation pathway, is tightly ...19921541396
inducible alkyltransferase dna repair proteins in the filamentous fungus aspergillus nidulans.we have investigated the response of the filamentous fungus aspergillus nidulans to low, non-killing, doses of the alkylating agent mnng (n-methyl-n'-nitro-n-nitrosoguanidine). such treatment causes a substantial induction of dna alkyltransferase activity, with the specific activity in treated cells increasing up to one hundred-fold. fluorography reveals the two main inducible species as proteins of 18.5 kda and 21 kda, both of which have activity primarily against o6-methylguanine (o6-meg) lesi ...19921542560
structure of the aspergillus nidulans qut repressor-encoding gene: implications for the regulation of transcription initiation.the nucleotide (nt) sequence of the qutr gene has been determined and shown to encode an inferred protein (qutr) of 929 amino acids (aa). the inferred aa sequence shows a high level of similarity throughout its length with the aa sequence of the three c-terminal domains (shikimate kinase; 3-dehydroquinase; shikimate dehydrogenase) of the pentafunctional arom protein of aspergillus nidulans that catalyses steps 2-6 in the shikimate pathway. the inferred qutr aa sequence has a completely conserved ...19921544567
transfer of isolated nuclei into protoplasts of aspergillus nidulans.nuclei were isolated from protoplasts of a haploid auxotrophic aspergillus nidulans strain. transformation of protoplasts prepared from a complementary haploid auxotrophic strain with these purified nuclei resulted in both heterokaryotic and diploid colonies. the nutritionally-complementing colonies appeared at a frequency of 5 x 10(-7) to 10(-8).19921547859
a comparison of the enzymological and biophysical properties of two distinct classes of dehydroquinase enzymes.this paper compares the biophysical and mechanistic properties of a typical type i dehydroquinase (dhqase), from the biosynthetic shikimate pathway of escherichia coli, and a typical type ii dhqase, from the quinate pathway of aspergillus nidulans. c.d. shows that the two proteins have different secondary-structure compositions; the type i enzyme contains approx. 50% alpha-helix while the type ii enzyme contains approx. 75% alpha-helix. the stability of the two types of dhqase was compared by de ...19921554351
protein kinases from aspergillus nidulans that phosphorylate the carboxyl-terminal domain of the largest subunit of rna polymerase ii.three serine kinases which phosphorylate the ctd of rna polymerase ii have been identified in aspergillus nidulans. the kinases (ki, kii, kiii) were identified using a synthetic peptide containing four copies of the ctd consensus heptamer repeat, and differ in chromatographic behavior, and apparent molecular mass (ki approximately 60kda; kii approximately 82kda; kiii approximately 43 kda). kiii utilized, in addition to peptide, histone h1 as substrate, whereas casein was not phosphorylated by an ...19921556138
disruption of a magnaporthe grisea cutinase gene.using a one-step strategy to disrupt cut1, a gene for cutinase, cut1- mutants were generated in two strains of magnaporthe grisea. one strain, pathogenic on weeping lovegrass and barley and containing the arg3-12 mutation, was transformed with a disruption vector in which the aspergillus nidulans argb+ gene was inserted into cut1. prototrophic transformants were screened by southern hybridization, and 3 of 53 tested contained a disrupted cut1 gene (cut1::argb+). a second strain, pathogenic on ri ...19921557024
sequence analysis of the gene coding for glyceraldehyde-3-phosphate dehydrogenase (gpd) of podospora anserina: use of homologous regulatory sequences to improve transformation efficiency.the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of podospora anserina has been isolated from a genomic library by heterologous hybridization with the corresponding gene of curvularia lunata. the coding region consists of 1014 nucleotides and is interrupted by a single intron. the amino-acid sequence encoded by the gpd gene shows a high degree of sequence identity with the corresponding gene products of various fungi. multiple alignments of all fungal gpd sequences so far available result ...19921563046
cloning and sequence determination of a cdna encoding aspergillus nidulans calmodulin-dependent multifunctional protein kinase.a partial cdna encoding aspergillus nidulans calmodulin-dependent multifunctional protein kinase (acmpk) was isolated from a lambda zap expression library by immunoselection using monospecific polyclonal antibodies to the enzyme. the sequence of both strands of the cdna (cmka) was determined. the deduced amino acid (aa) sequence contained all eleven consensus domains found in serine/threonine protein kinases [hanks et al., science 241 (1988) 42-52], as well as a putative calmodulin-binding domai ...19921563634
identification of the promoter region involved in the autoregulation of the transcriptional activator alcr in aspergillus nidulans.the alcr protein is the transcriptional activator of the ethanol utilization pathway in the filamentous fungus aspergillus nidulans. this activator belongs to a family of fungal proteins having a conserved dna-binding domain containing six cysteines (c6 class) with some striking features. at variance with other motifs of this class, the binding domain of alcr is strongly asymmetrical in relation to the central cysteines and moreover was predicted to adopt a helix-turn-helix structure. this domai ...19921569930
effects of mutagen-sensitive mus mutations on spontaneous mitotic recombination in aspergillus.methyl methane-sulfonate (mms)-sensitive, radiation-induced mutants of aspergillus were shown to define nine new dna repair genes, musk to muss. to test mus mutations for effects on mitotic recombination, intergenic crossing over was assayed between color markers and their centromeres, and intragenic recombination between two distinguishable ade alleles. of eight mutants analyzed, four showed significant deviations from mus+ controls in both tests. two mutations, musk and musl, reduced recombina ...19921582555
cooperative regulation of cell proliferation by calcium and calmodulin in aspergillus nidulans.calcium and calmodulin have been widely implicated in the control of cell proliferation. we have created a strain of the genetically tractable filamentous fungus, aspergillus nidulans, that is conditional for calmodulin expression. this was accomplished by replacing the unique endogenous calmodulin gene with one regulated by the inducible alcohol dehydrogenase (alca) gene promoter by homologous recombination. this strain cannot grow when the cells are incubated in medium containing a carbon sour ...19921584213
regulation of aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acva and ipna by glucose.expression of the aspergillus nidulans penicillin biosynthesis genes acva and ipna, encoding delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase and isopenicillin n synthetase, respectively, was analyzed. the intergenic region carrying the divergently oriented promoters was fused in frame in both orientations to escherichia coli lacz and e. coli uida reporter genes. each construct permits simultaneous expression studies of both genes. transformants of a. nidulans carrying a single copy o ...19921592830
functional analysis of the expression of the 3'-phosphoglycerate kinase pgk gene in aspergillus nidulans.a functional analysis of the aspergillus nidulans 3-phosphoglycerate kinase pgk promoter was undertaken using gene fusions to the lacz gene of escherichia coli, and introducing these into a beta-galactosidase-deficient strain of a. nidulans. expression of a particular gene fusion in transformed strains depends upon the site of integration of the vector into the genome, and when specifically targeted to the catabolic quinate dehydrogenase qute (selective marker) locus is directly proportional to ...19921603065
isolation and characterization of the aspergillus niger pyruvate kinase gene.the aspergillus niger gene encoding pyruvate kinase was cloned by heterologous hybridization using a fragment from the corresponding yeast gene as a probe. the primary structure of the gene, including 5' and 3' flanking sequences, was determined. the structural part of the a. niger pkia gene is 2054 bp long and is interrupted by seven putative introns. splicing of the intron sequences results in an open reading frame of 1578 bp, encoding a protein of 526 amino-acid residues and a molecular weigh ...19921611667
fungi associated with bovine abortion in the northern plains states (usa).mycotic infection was diagnosed in 6.8% of 6,858 cases of bovine abortion and stillbirth examined during a 9-year period. aspergilli were associated with approximately 5% of all abortion cases and 71% of 446 cases that were cultured for fungi and diagnosed as mycotic abortion. aspergillus fumigatus was the most frequent isolate (62%), followed by a. terreus (6.7%), emericella (aspergillus) nidulans (3.0%), a. flavus (2.9%), and e. rugulosus (less than 1.0%). zygomycetes (absidia, mortierella, rh ...19921616983
carbon catabolite repression can account for the temporal pattern of expression of a penicillin biosynthetic gene in aspergillus nidulans.aspergillus nidulans synthesizes penicillins as secondary metabolites when grown under certain culture conditions. broths containing carbon (c) sources that give rise to carbon catabolite repression (ccr) support a much lower antibiotic yield than broths with non-repressing c sources. steady-state levels of the isopenicillin n synthetase (ipns) gene transcript are considerably reduced in mycelia grown with repressing c sources and are depressed in mycelia grown with sugars which do not cause ccr ...19921625576
roles of fad and 8-hydroxy-5-deazaflavin chromophores in photoreactivation by anacystis nidulans dna photolyase.dna photolyase from the cyanobacterium anacystis nidulans contains two chromophores, flavin adenine dinucleotide (fadh2) and 8-hydroxy-5-deazaflavin (8-hdf) (eker, a. p. m., kooiman, p., hessels, j. k. c., and yasui, a. (1990) j. biol. chem. 265, 8009-8015). while evidence exists that the flavin chromophore (in fadh2 form) can catalyze photorepair directly and that the 8-hdf chromophore is the major photosensitizer in photoreactivation it was not known whether 8-hdf splits pyrimidine dimer direc ...19921639785
the bimb3 mutation of aspergillus nidulans uncouples dna replication from the completion of mitosis.a conditionally lethal mutation in the bimb gene of aspergillus nidulans disrupts the normal regulatory patterns associated with mitotic events. this results in dna replication in the absence of the completion of mitosis in the mutant at restrictive temperature. this defect yields large polyploid nuclei after several hours at restrictive temperature. the bimb gene has been cloned by genetic mapping and chromosome walking from the previously cloned amds gene. the cloned dna complements the temper ...19921639810
cloning of chromosome i dna from saccharomyces cerevisiae: analysis of the fun52 gene, whose product has homology to protein kinases.a gene whose product has homology to protein kinases and is closely related to the aspergillus nidulans nima cell-cycle gene was identified on chromosome i of the yeast, saccharomyces cerevisiae. this gene has been temporarily designated fun52, where fun is the acronym for 'function unknown now'. in a. nidulans, nima is required to enter mitosis. in addition, overexpression of nima causes premature onset of mitosis and cell cycle arrest. in contrast, s. cerevisiae cells that were either deleted ...19921644305
in vivo overproduction of the pentafunctional arom polypeptide in aspergillus nidulans affects metabolic flux in the quinate pathway.the shikimate pathway and the quinic acid utilisation (qut) pathway of aspergillus nidulans and other fungi share the two common metabolic intermediates, 3-dehydroquinic acid (dhq) and dehydroshikimic acid (dhs), which are interconverted by two isoenzymes, catabolic 3-dehydroquinase, (cdhqase) and biosynthetic dehydroquinase, (bdhqase). bdhqase is one of five consecutive enzymatic activities associated with the pentafunctional arom protein encoded by the complex arom locus, whereas cdhqase is en ...19911648168
a cdna encoding rabbit muscle protein phosphatase 1 alpha complements the aspergillus cell cycle mutation, bimg11.the bimg11 allele causes a conditional growth defect in the fungus aspergillus nidulans preventing both progression through mitosis and normal polar growth. previously, we have shown that the bimg11 mutation increases the phosphorylation of nuclear proteins and that the gene encodes a protein similar to mammalian type 1 protein phosphatase. assay of protein phosphatase activity in protein extracts of aspergillus demonstrates directly that type 1 phosphatase activity is greatly reduced in the mut ...19911655766
diverse proteins homologous to inositol monophosphatase.bovine inositol monophosphatase (imp) and several homologous proteins were found to share two sequence motifs with bovine inositol polyphosphate 1-phosphatase (ipp). these motifs may correspond to binding sites within imp and ipp for inositol phosphates or for lithium, since both substances are bound by these proteins. this suggests that the proteins homologous to imp, which have diverse biological roles but whose function is not clear, may act by enhancing the synthesis or degradation of phosph ...19911660408
two alpha-tubulin genes of aspergillus nidulans encode divergent proteins.we have isolated and analyzed the tuba and tubb alpha-tubulin genes of aspergillus nidulans. the nucleotide sequences of these genes predict polypeptides of 447 amino acids for tuba and 450 for tubb. the predicted amino acids sequences exhibit 28% divergence between the two polypeptides. this is the second known case of such high divergence between alpha-tubulins within the same species. the tubb gene is unique in that it codes for an extra glycine residue between what are usually the second and ...19911672037
is there methylmalonyl coa mutase in aspergillus nidulans?in most animal species and many prokaryotes, methylmalonyl coa mutase catalyzes isomerization between methylmalonyl coa and succinyl coa using adenosylcobalamin as a cofactor. we describe the absence of this enzyme in aspergillus nidulans based on the absence of enzyme activity in vitro and the failure to metabolize methylmalonate or grow in media containing this organic acid as the sole carbon source. these data contrast previous assumptions that propionate may be metabolized through propionyl ...19911676260
isolation and expression of the acetate-inducible isocitrate lyase gene (acu-3) from neurospora crassa: evidence for a second constitutive isozyme.heterologous hybridisation of the aspergillus nidulans structural gene for isocitrate lyase (acud) to a lambda genomic library of neurospora crassa identified a recombinant phage containing the hybridising sequence on an internal 9 kb ecori fragment. a restriction fragment length polymorphism (rflp) enabled the fragment to be assigned to linkage group v (lg v), the location of the acetate-inducible isocitrate lyase, acu-3 of neurospora. functional ectopic complementation by co-transformation of ...19911681413
sequence and expression of gln3, a positive nitrogen regulatory gene of saccharomyces cerevisiae encoding a protein with a putative zinc finger dna-binding domain.the gln3 gene of saccharomyces cerevisiae is required for the activation of transcription of a number of genes in response to the replacement of glutamine by glutamate as source of nitrogen. we cloned the gln3 gene and constructed null alleles by gene disruption. gln3 is not essential for growth, but increased copies of gln3 lead to a drastic decrease in growth rate. the complete nucleotide sequence of the gln3 gene was determined, revealing one open reading frame encoding a polypeptide of 730 a ...19911682800
botran and bleomycin induce crossing-over, and bleomycin also increases aneuploidy in diploid strains of aspergillus.both bleomycin, an antineoplastic drug, and botran (2,6-dichloro-4-nitro-aniline), a fungicide, are known to inhibit growth and induce genetic segregation in diploid tester strains of aspergillus nidulans when present in agar media. to identify primary effects, samples of induced apparent crossover types were analysed in detail. for both compounds, coincident and consecutive events of mitotic crossing-over were found to be very frequent and such events showed a random distribution among isolated ...19901692105
characterization and comparison of mitochondrial dnas and rrnas from penicillium urticae and p. chrysogenum.mitochondrial dna (mt dna) from a patulin producer, penicillium urticae (synonym p. griseofulvum), was 27.8 kb +/- 0.6 kb in size by electron microscopy and 27.2 kb by agarose gel electrophoresis. restriction endonuclease maps for nine restriction enzymes were constructed, and eleven fragments which covered the total range of the mt dna were cloned into the escherichia coli plasmid vector puc19. southern analysis of the native genomes of p. urticae and p. chrysogenum with six of the cloned fragm ...19901697325
a negative regulator of mitosis in aspergillus is a putative membrane-spanning protein.the temperature-sensitive cell cycle mutation bime7 of aspergillus nidulans causes cells to become blocked in mitosis at a restrictive temperature. previous work has shown that this mitotic block is induced even when cells are arrested in the s or g2 phase. the mitotic block is also observed in cells carrying a null mutation in bime, obtained by molecular disruption of the gene (osmani, s.a., engle, d.b., doonan, j.h., and morris, n.r. (1988) cell 52, 241-251), indicating that a lack of bime fun ...19901697851
optimized vectors and selection for transformation of neurospora crassa and aspergillus nidulans to bleomycin and phleomycin resistance.to provide a dominant selectable marker for transformation of neurospora crassa strains lacking specific auxotrophic mutations, we have engineered the bleomycin (bm) resistance-encoding gene (ble) from the bacterial transposon tn5 for expression in n. crassa. the coding region of the ble gene was fused to the promoter and terminator regions of the n. crassa am gene. in some vectors, multiple cloning sites were placed flanking the ble gene to provide a versatile ble cassette. when introduced into ...19901699844
keratinophilic fungi and other moulds associated with air-dust particles from egypt.one-hundred and eleven species and three species varieties belonging to 39 genera were collected from 50 dust samples on the five media used at 28 degrees c. using the hair-baiting technique with horse hair, 10 species of chrysosporium were isolated: c. asperatum, c. state of arthroderma tuberculatum, c. indicum, c. inops, c. keratinophilum, c. merdarium, c. pannorum, c. queenslandicum, c. tropicum and c. xerophilum. true dermatophytes were isolated: trichophyton verrucosum and trichophyton sp. ...19901702081
cloning by differential screening of a xenopus cdna that encodes a kinesin-related protein.by differential screening of a xenopus egg cdna library, we selected nine clones (eg1 to eg9) corresponding to mrnas which are deadenylated and released from polysomes soon after fertilization. the sequence of one of these clones (eg5) revealed that the corresponding protein has the characteristic features of a kinesin-related protein. more specifically, eg5 was found to be nearly 30% identical to a kinesin-related protein encoded by bimc, a gene involved in nuclear division in aspergillus nidul ...19911710028
characterization of aspergillus nidulans mutants deficient in cell wall chitin or glucan.by screening for the osmotically remediable phenotype, mutations in two genes (orla and orlb) affecting the cell wall chitin content of aspergillus nidulans were identified. strains carrying temperature-sensitive alleles of these genes produce conidia which swell excessively and lyse when germinated at restrictive temperatures. growth under these conditions is remedied by osmotic stabilizers and by n-acetylglucosamine (glcnac). remediation by glcnac suggests that the mutations affect early steps ...19921729232
molecular characterization of the lam locus and sequences involved in regulation by the amdr protein of aspergillus nidulans.the lam locus of aspergillus nidulans consists of two divergently transcribed genes, lama and lamb, involved in the utilization of lactams such as 2-pyrrolidinone. both genes are under the control of the positive regulatory gene amdr and are subject to carbon and nitrogen metabolite repression. the lamb gene and the region between the two genes have been sequenced, and the start points of transcription have been determined. within the lam locus are two sequences with homology to elements, requir ...19921729609
an intragenic map of the brla locus of aspergillus nidulans.we have constructed an intragenic map for the aspergillus nidulans brla gene, mutants in which are distinguishable by visual criteria only. most of the leaky phenotype mutants map near the right (3') end. the gene shows distinct recombinational polarity consistent with recombination initiation at the promoter (centromere-proximal) end of the gene. brla12 and brla20 mutants gave abnormal dna restriction patterns consistent with the iii; viii and vi; viii translocations, respectively, determined b ...19921736092
codon usage in aspergillus nidulans.synonymous codon usage in genes from the ascomycete (filamentous) fungus aspergillus nidulans has been investigated. a total of 45 gene sequences has been analysed. multivariate statistical analysis has been used to identify a single major trend among genes. at one end of this trend are lowly expressed genes, whereas at the other extreme lie genes known or expected to be highly expressed. the major trend is from nearly random codon usage (in the lowly expressed genes) to codon usage that is high ...19911745237
heterologous expression of the aspergillus nidulans regulatory gene nira in fusarium oxysporum.we have isolated strains of fusarium oxysporum carrying mutations conferring a phenotype characteristic of a loss of function in the regulatory gene of nitrate assimilation (nira in aspergillus nidulans, nit-4 in neurospora crassa). one of these nir- mutants was successfully transformed with a plasmid containing the nira gene of a. nidulans. the nitrate reductase of the transformants is still inducible, although the maximum activity is lower than in the wild type. single and multiple integration ...19911756977
isolation and nucleotide sequence of the ribosomal protein s16-encoding gene from aspergillus nidulans.a genomic clone has been isolated from aspergillus nidulans which is homologous to the ribosomal (r) protein s16-encoding gene of saccharomyces cerevisiae (s16a) and the r-protein s19-encoding gene of rat (s19). the amino acid (aa) sequences, deduced from nucleotide (nt) sequence analysis, show that in both cases more than 63% of the aa are conserved. the proposed a. nidulans r-protein s16 gene (rps16) differs from that of s. cerevisiae in that it occurs as a single copy in the haploid genome (r ...19911761226
regulatory functions of calmodulin.calmodulin is a ca2+ binding protein present in all eukaryotic cells that serves as the primary intracellular receptor for ca2+. this 148 amino acid protein is involved in activation of more than 20 enzymes which mediate a wide variety of physiological processes. many of these enzymes are inhibited in an intramolecular manner and the ca(2+)-calmodulin complex relieves this inhibition. calmodulin is essential for life as disruption of the gene in genetically tractable organisms is lethal. this pr ...19911763137
the uay positive control gene of aspergillus nidulans: fine structure, isolation of constitutive mutants and reversion patterns.the product of the uay gene of aspergillus nidulans is necessary for the expression of at least eight genes coding for enzymes and permeases of the purine utilisation pathway. a detailed fine structure map has been constructed of this gene involving 13 presumed point mutations and eight deletions. gene conversion of these deletions was demonstrated. a technique was devised to select for constitutive mutations and two were obtained which map within the uay gene. we have shown that the most centro ...19911766434
molecular cloning of the uay regulatory gene of aspergillus nidulans reveals a favoured region for dna insertions.the cloning of the positive regulatory gene, uay, which mediates uric acid induction of enzymes and permeases of the purine degradation pathway in the fungus aspergillus nidulans is described here. the 4 kb uay transcript is constitutively synthesised, it is not repressed by ammonia and its transcription does not require the area wide-domain transcription factor. we have determined that four deletions, which have been genetically characterised, are confined to a segment of 0.9 kb. two other dele ...19911766435
isolation of nuclei from aspergillus nidulans protoplasts.intact nuclei were isolated from the protoplasts of the filamentous fungus aspergillus nidulans. the large amounts of protoplasts required for such nuclear preparations were produced from young mycelia grown in liquid culture. for final purification of the crude nuclear fraction, a nycodenz density-gradient centrifugation was applied. the resulting nuclei were of good purity and morphological state, as demonstrated by fluorescence microscopy and electronmicroscopy. the weight ratio of dna:rna:pr ...19911769520
the fission yeast gamma-tubulin is essential for mitosis and is localized at microtubule organizing centers.gamma-tubulin exists in fission yeast as the product of an essential gene, encoding a 446 amino acid protein that is 77.3% identical to aspergillus nidulans gamma-tubulin. the gene disruption caused cell lethality, displaying condensed, undivided chromosomes with aberrant spindle structures. anti-gamma-tubulin staining showed that gamma-tubulin is located, throughout the wild-type cell cycle, at the spindle pole bodies (spbs), indicating that gamma-tubulin associates with interphase spb in the a ...19911770000
bima encodes a member of the tetratricopeptide repeat family of proteins and is required for the completion of mitosis in aspergillus nidulans.the recessive, temperature-sensitive bima1 mutation of aspergillus nidulans blocks nuclei in metaphase at restrictive temperature. to determine whether the bima product is essential, integrative transformation was used to create a mutation in the bima gene. the mutation was maintained in a heterokaryon and the phenotype of spores produced by the heterokaryon was analyzed. molecular disruption of the wild-type bima gene is recessive in the heterokaryon and causes a metaphase block, demonstrating ...19911770001
relationships between phosphatidylcholine content, chitin synthesis, growth, and morphology of aspergillus nidulans choc.the phosphatidylcholine (pc) content of aspergillus nidulans choc was varied by growing the auxotroph in medium containing various concentrations of choline chloride. direct linear correlations were observed between pc content and in vivo chitin synthase activity, between in vivo chitin synthase activity and mean hyphal extension rate, and between mean hyphal extension rate and hyphal growth unit length; hyphal growth unit length is a measure of hyphal branching. further, there was a correlation ...19911778430
the development of aspergillus niger var. awamori as a host for the expression and secretion of heterologous gene products. 19911783197
altered expression of the steroid bioconverting pathway in pan 7-1 transformants of cochliobolus lunatus.the filamentous fungus c. lunatus converts progesterone mainly to its 11 beta-hydroxy derivative. c. lunatus transformed with the plasmid pan 7-1, which contains the e. coli hph gene expressed under the control of the a. nidulans gpd and trpc expression signals, lacks this activity, but exhibits acetyl side chain degradation of progesterone through the reaction scheme progesterone----20 beta-hydroxy-progesterone----delta 4-androstene-3,17-dione---- testolactone + testosterone. the main part of t ...19911807829
mycofloral changes and aflatoxin contamination in stored chickpea seeds.chickpea seeds entering store carry a microflora of 'field' and 'storage' fungi. field fungi gradually disappear and storage fungi then predominate. these fungi especially aspergillus flavus, a. niger, a. nidulans, a. ochraceus and penicillium spp. grow vigorously and initiate grain spoilage and aflatoxin elaboration. the shift in mycofloral spectrum was more rapid in seeds stored in jute bags than those stored in metal bins. moisture content and aflatoxin contamination in seeds of jute bags was ...19911812019
role of the cell-cycle-regulated nima protein kinase during g2 and mitosis: evidence for two pathways of mitotic regulation. 19911819506
kinesin-like proteins of aspergillus nidulans. 19911819513
heterologous expression and regulation of the neurospora crassa nit-4 pathway-specific regulatory gene for nitrate assimilation in aspergillus nidulans.the nira gene of aspergillus nidulans and the nit-4 gene of neurospora crassa appear to be equivalent pathway-specific regulatory genes which mediate nitrate induction of nitrate reductase and nitrite reductase (nr and nir) activities. we have transformed the nit-4 wild-type (wt) gene into the a. nidulans loss-of-function (pleiotropic negative) nira 1 mutant strain. the nit-4 gene was found to complement the nira 1 mutation, thus permitting the nira 1 mutant strain to grow on nitrate or nitrite ...19911829047
[exogenous allergic alveolitis in tobacco industry workers]. 19911831935
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
sequence of the nuclear atp synthase subunit 9 gene of podospora anserina: lack of similarity to the mitochondrial genome.the nuclear gene coding for the mitochondrial subunit 9 of the f0f1-atp synthase complex was isolated from a genomic library of podospora anserina. nucleotide sequencing revealed an open reading frame capable to code for 144 amino acids including an amino-terminal pre-sequence of 63 amino acid residues for mitochondrial import of the pre-proteolipid. the p. anserina proteolipid shows extensive sequence identity with the corresponding gene products of the related filamentous fungi neurospora cras ...19911834355
cloning and molecular characterization of the acetamidase-encoding gene (amds) from aspergillus oryzae.we have isolated an acetamidase-encoding gene (amds) from aspergillus oryzae by heterologous hybridization using the corresponding aspergillus nidulans gene as a probe. the gene is located on a 3.5-kb saci fragment and its nucleotide (nt) sequence was determined. compared with the a. nidulans amds gene, the coding region of a. oryzae gene consists of seven exons interrupted by six introns and encodes 545 amino acid (aa) residues. the deduced aa sequence has a high degree of homology with that of ...19911840550
nit-4, a pathway-specific regulatory gene of neurospora crassa, encodes a protein with a putative binuclear zinc dna-binding domain.nit-4, a pathway-specific regulatory gene in the nitrogen circuit of neurospora crassa, is required for the expression of nit-3 and nit-6, the structural genes which encode nitrate and nitrite reductase, respectively. the complete nucleotide sequence of the nit-4 gene has been determined. the predicted nit4 protein contains 1,090 amino acids and appears to possess a single zn(ii)2cys6 binuclear-type zinc finger, which may mediate dna binding. site-directed mutagenesis studies demonstrated that c ...19911840634
temporal and spatial controls of aspergillus development.the mechanisms regulating elaboration of the multicellular asexual reproductive apparatus, the conidiophore, of the filamentous ascomycete aspergillus nidulans provide a model for the control of fungal development. recent advances have been made on three fronts. first, new physical and chemical signals have been discovered that control commitment of cells to the conidiation pathway. second, positively acting developmental regulatory genes have been cloned and characterized. in addition, evidence ...19911840892
domain structure and interaction within the pentafunctional arom polypeptide.the arom locus of aspergillus nidulans specifies a pentafunctional polypeptide catalysing five consecutive steps leading to the production of 5-enolpyruvylshikimate 3-phosphate in the shikimate pathway. aided by oligonucleotide-mediated site-directed mutagenesis, the whole arom locus and various overlapping subfragments from within it have been fused to the powerful hybrid trc promoter in the escherichia coli plasmid pkk233-2. expression of these subfragments in appropriate aro mutants of e. col ...19911849480
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
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