Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
light-induced absorbance changes in cell-free extracts of neurospora crassa. 2002135267
isolation and characterization of a mutant of neurospora crassa deficient in general amino acid permease activity.a mutant of neurospora crassa (pm-nbg27) was isolated on the basis of its resistance of p-fluoro-phenylalanine on ammonium-deficient vogel's medium. this mutant was found to be devoid of both conidial and post-conidial (after 180 min of preincubation) transport activity of all amino acids. genetic analysis of pm-nbg27 by crossing it to wild-type (74a) resulted in the predicted segregants exhibiting transport characteristics of pm-n, pm-b, pm-g, pm-nb, pm-ng, pm-bg and parental types. the above o ...2002127619
influence of an aggregated multienzyme system on transient time: kinetic evidence for compartmentation by an aromatic-amino-acid synthesizing complex of neurospora crassa.the aromatic complex of neurospora crassa is an aggregated multienzyme system which catalyzes five consecutive reactions in the central pathway leading to the biosynthesis of the aromatic amino acids. in an attempt to understand the physiological importance of this complex in particular, as well as the importance of cellular organization of enzyme systems in general, we have isolated the complex and have begun to characterize its catalytic properties. optimum conditions for the assay of the over ...2002128001
stimulation of folate metabolism by exogenous glycine in neurospora crassa wild type. 2002124265
regulation of 2-phosphoenolpyruvate carboxykinase and isocitrate lyase syntheses in neurospora crassa. 2002123004
genetic and metabolic regulation of purine base transport in neurospora crassa.neurospora crassa can utilize various purine bases such as xanthine or uric acid and their catabolic products as a nitrogen source. the early purine catabolic enzymes in this organism are regulated by induction and by ammonium repression. studies were undertaken to investigate purine base transport and its regulation in neurospora. the results of competition experiments with uric acid and xanthine transport strongly suggest that uric acid and xanthine share a common transport system. it was also ...2002139563
genetic evidence on the organization and action of the qa-1 gene product: a protein regulating the induction of three enzymes in quinate catabolism in neurospora crassa.the first three reactions in the catabolism of qainic acid in neurospora crassa are under the genetic control of the qa gene cluster. this cluster consists of three structural genes encoding three inducible enzymes plus a regulatory gene (qa-1+) whose diffusible product apparently acts in a positive fashion to initiate coordinate synthesis of the three enzymes when an appropriate inducer is present. genetic and biochemical evidence for both complementing and temperature-sensitive qa-1 alleles in ...2002123642
6-phosphogluconate dehydrogenase from neurospora crassa. 2002124005
enzymes of neurospora crassa which attack uv-irradiated dna.two excision-deficient mutants of neurospora crassa contain normal levels of two enzymes, a single-strand-specific exonuclease and a single-strand specific endonuclease, which attack uv-irradiated dna. mutants of n. crassa have been obtained in which the activity of the latter enzyme as well as an activity with native dna are simultaneously affected. these activities are also apparently low in excision-proficient uvs3 strain of n. crassa which has many of the characteristics of the reca mutants ...2002127578
siroheme: a prosthetic group of the neurospora crassa assimilatory nitrite reductase.the neurospora crassa assimilatory nitrite reductase (ec 1.6.6.4) catalyzes the nadph-dependent reduction of nitrite to ammonia, a 6-electron transfer reaction. highly purified preparations of this enzyme exhibit absorption spectra which suggest the presence of a heme component (wavelength maxima for oxidized senzyme: 390 and 578 nm). there is a close correspondence between nitrite reductase activity and absorbance at 400 nm when partially purified nitrite reductase preparations are subjected to ...2002126995
glycogen synthesis in the fungus neurospora crassa.an enzymic activity, obtained from neurospora crassa, catalyzing the incorporation of [14c]glucose from adp-[14c]glucose into a glucan of the glycogen type, is described. the properties of the adpglucose : glycogen glucosyltransferase as compared with those of the already known udp glucose : glycogen glucosyltransferase were studied. the radioactive products obtained with udp-14c]glucose or adp-[14c]glucose released all the radioactivity as maltose after alpha or beta amylase treatment. glucose ...2002148915
recombination in the am gene of neurospora crassa--a new model for conversion polarity and an explanation for a marker effect.it is argued that polarised intragenic recombination is not necessarily due to hybrid dna extending into the gene for variable distances from one side; it can as well be explained by hybrid dna usually covering the whole gene, the two complementary dna strands of the gene having unequal chances of undergoing the interchromatid transfer involved in hybrid dna formation, and excision from base-pair mismatches proceeding predominantly in one chemical direction (perhaps 5' to 3'). this alternative m ...2002130365
reproducibility of vitamin assays with mutants of neurospora crassa maintained by freeze-drying.three mutant strains (atcc 9277, atcc 9278, atcc 9683) of neurospora crassa requiring choline, inositol, and p-aminobenzoic acid respectively for normal growth were deposited at the atcc by g.w. beadle 30 years ago and were preserved at various time intervals by freeze-drying. each preservation batch yielded cultures that, when used for biological assays, exhibited the same biochemical properties as they originally possessed. the freeze-drying technique is shown to be applicable to preserving bi ...2002134828
biochemical genetic studies of cycloheximide resistance in neurospora crassa.genetic analysis of a number of cycloheximide-resistant mutants of neurospora crassa has shown that resistance is controlled by several genes. two of these appear to be located on linkage group v. resistance to the antibiotic is dominant in wild-type-mutant heterokaryons. two types of cycloheximide-resistant mutants were isolated: one type exhibited colonial morphology only when grown in the presence of cycloheximide and the other type maintained normal morphology even at high concentrations of ...2002126683
induced transfer of higher plant chloroplasts into fungal protoplasts.chloroplasts isolated from spinach leaves have been transferred in large numbers into protoplasts of neurospora crassa with the help of polyethylene glycol. the chloroplasts show high photosynthetic activity--at least until the time of uptake--and the protoplasts continue to show active cytoplasmic streaming after chloroplast uptake.2002127380
genetic alterations of ribonuclease-sensitive glycoprotein subunits of amino acid transport systems in neurospora crassa conidia. 2002123728
amino acid sequence of tyrosinase from neurospora crassa.the amino-acid sequence of tyrosinase from neurospora crassa (monophenol,dihydroxyphenylalanine:oxygen oxidoreductase, ec 1.14.18.1) is reported. this copper-containing oxidase consists of a single polypeptide chain of 407 amino acids. the primary structure was determined by automated and manual sequence analysis on fragments produced by cleavage with cyanogen bromide and on peptides obtained by digestion with trypsin, pepsin, thermolysin, or chymotrypsin. the amino terminus of the protein is ac ...2002151279
adenylosuccinate amp-lyase (neurospora crassa). 2002151182
regulation of phosphate metabolism in neurospora crassa: identification of the structural gene for repressible acid phosphatase.a mutant of neurospora crassa with an altered repressible acid phosphatase has been isolated. the enzyme is much more thermolabile than that of wild type, and has an increased michaelis constant. tests of allelic interactions (in partial diploids) and in vitro mixing experiments were consistent with the mutation being in the structural gene for the enzyme. this gene, pho-3, was found to be located in the right arm of linkage group iv (lgiv). thus, pho-3 and the structural gene for repressible al ...2002137163
re-investigation of the effects of l-glutamine and l-asparagine on the neurospora crassa nadp-specific glutamate dehydrogenase.l-glutamine, when purified free of traces of nh4+ present in solution, does not act as an alternative substrate to nh4+ for the nadp-specific glutamate dehydrogenase of neurospora. l-glutamine interferes with detection of small quantities of nh4+ by nessler's reagent. l-asparagine is not an alternative substrate to nh4+ for this enzyme.2002137720
randomness tests on the sequence of ascal segregation classes in neurospora crassa.various statistical tests for randomness were made on the order of ascal classes in groups of asci from wild-type x asco crosses. there was no significant nonrandom clustering of asci of the same segregation class, nor a regular twinning of similar asci. any apparent observed clustering of similar ascal classes is probably an artefact or due to chance. 2 x n x2 tests showed that frequencies of individual ascus classes from different perithecia were generally homogeneous, as were second division ...2002137884
phosphocellulose, an affinity chromatographic system for chorismate synthase and the aromatic complex of neurospora crassa. 2002128358
determination of total choline in biological materials.a microbiological eight-point parallel line assay for the determination of choline has been developed, using neurospora crassa cholineless-1 as test organism. in the common procedure the mold is grown at 25 degrees c in 25 ml basal medium at ph 5.9-6.0. growth studies showed, however, that a better log dose-response curve, with respect to the linear part of the curve, was obtained when the organism was grown at 30 degrees c, in 20 ml experimental volume and at ph 5.5. the proprosed eight-point a ...2002129440
gene order in the qa gene cluster of neurospora crassa.four different types of crosses have been used to establish the order of the four genes in the qa gene cluster of neurospora crassa, which encode the following proteins involved in the inducible catabolism of quinic acid: a regulatory (activator) protein (qa-1), catabolic dehydroquinase (qa-2), quinate dehydrogenase (qa-3), and dehydroshikimate dehydrase (qa-4). the four crosses involved (1) the ordering of the four qa genes relative to the closely-linked me-7 locus; (2) the ordering of the thre ...2002134253
correlation of enzymatic activity and thermal resistance with hydration state in ungerminated neurospora conidia.ungerminated neurospora crassa conidia were incubated at 0, 50, and 100% relative humidity, giving rise to conidia in dry, quasi-dry, and wet hydration states, respectively. metabolic activity was detected by monitoring levels of reduced glutathione (gsh), oxidized glutathione (gssg), and the soluble-amino acid pools as a function of incubation time. wet conidia (approximately 65% water content) exhibited significant metabolic activity as evidenced by: (i) reduction of gssg to gsh, (ii) degradat ...2002151096
some required events in conidial germination of neurospora crassa. 2002136375
on the metabolic role of thymidine 2'-hydroxylase (thymidine, 2-oxoglutarate: oxygen oxidoreductase, ec 1.14.11.3) in neurospora crassa. 2002136368
biogenesis of mitochondrial membranes in neurospora crassa. mitochondrial protein synthesis during conidial germination.the conidia of neurospora crassa entered logarithmic growth after a 1-h lag period at 30 degrees c. although [14c]leucine is incorporated quickly early in growth, cellular protein data indicated that no net protein synthesis occurred until after 2 h of growth. neurospora is known to produce ethanol during germination even though respiratory enzymes are present. also, neurospora mitochondria isolated from cells less than 3-h old are uncoupled. since oxygen uptake increased during germination, was ...2002126153
the interactive effect of ultraviolet irradiation and 5-bromouracil at the rib-1 locus in neurospora crassa.5-bromouracil (5-bu) was shown to enhance reverse mutation rates when added to conidia of a rib-1 strain of neurospora crassa previously irradiated with ultraviolet light. a comparison is presented between various incubation intervals in the presence and absence of 5-bu while varying the uv dose. an increase in mutation frequency ranging from 0.028 - 2.05 x 10(2) times greater than the spontaneous frequency, uv frequency alone or 5-bu frequency alone was observed when uv irradiation and 5-bu wer ...2002126795
a reduced pyridine nucleotides-diaphorase activity associated to the assimilatory nitrite reductase complex from neurospora crassa.the neurospora crassa assimilatory nad(p)h-nitrite reductase complex has associated a nad(p)h-diaphorase activity. 1. this nad(p)h-diaphorase activity can use either mammalian cytochrome c, 2,6--dichlorophenol-indophenol, ferricyanide, or menadione as electron acceptor from the reduced pyridine nucleotides, and requires flavin adenine dinucleotide for maximal activity. 2. it is inhibited by p-hydroxymercuribenzoate, 1 mum, and it is unaffected by cyanide, sulfite, or arsenite at concentrations w ...2002136235
mutation induction by difunctional alkylating agents in neurospora crassa.the genetic characterization of ad-3 mutants of neurospora crassa induced by two carcinogenic difunctional akylating agents, 1,2,4,5-diepoxypentane (dep) and 1,2,7,8-diepoxyoctane (deo), has shown that point mutations at the ad-3b locus have similar complementation patterns. in addition to the induction of point mutations, dep induces a low frequency (7.5%) of multilocus deletions, whereas deo induces an extremely high frequency (42.0%). the distribution of the different classes of ad-3 mutants ...2002133852
coordinate activation of a multienzyme complex by the first substrate. evidence for a novel regulatory mechanism in the polyaromatic pathway of neurospora crassa. 2002130831
ultraviolet-inactivation of conidia from heterokaryons of neurospora crassa containing uv-sensitive mutations.the effect of three uv-sensitive mutations of neurospora crassa, upr-i, uvs-4 and uvs-6, on the ultraviolet-inactivation of conidia from two-component heterokaryons was investigated. in two-component heterokaryons with wild-type sensitivity to radiation inactivation, all three conidial fractions exhibited similar ultraviolet-inactivation curves. each uv-sensitive mutation studied uniquely modified the ultraviolet-inactivation curves of conidia from two-component heterokaryons. in heterokaryons h ...2002123634
induction by rna of inositol independence in neurospora crassa.the effect of purified wild-type rna (allo-rna) on genetic reversion of inositol-requiring mutant 89601 of neurospora crassa is described. the mutant (inos minus) strain, on treatment with the wild-type rna preparation, was found to revert to wild type (inos+) in significant numbers. rna from the mutant (iso-rna) and allo-rna digested by rnase were ineffective in causing genetic reversion at the inositol locus. the allo-rna-induced revertants were stable and showed a mendelian transmission of th ...2002123644
the mechanism of arsenate inhibition of the glucose active transport system in neurospora crassa. 2002123729
a kinetic study of thymine 7-hydroxylase from neurospora crassa.the steady-state kinetics of thymine 7-hydroxylase (thymine, 2-oxoglutarate dioxygenase, ec 1.14.11.6) has been investigated. initial velocity plots were all found to be linear and intersecting. variation in concentration of two of the substrates, when the third substrate was at a constant high or low concentration, gave initial velocity plots that conform to an ordered sequential mechanism, where thymine is the second substrate to add. with 5-carboxyuracil, which is the end product in the seque ...2002126696
[possible physiological role of the "high molecular weight polyphosphate-polyphosphate phosphohydrolase" system in neurospora crassa].the biosynthesis of polyphosphatase and the system of active transport of glucose is repressed in the cells of neurospora crassa by glucose at a high concentration. there is a strict correlation between the activity of polyphosphatase and the initial rate of glucose active transport. both systems are repressed during the growth of the mycelium on a glucose medium and are repaired on a medium without glucose. the latter process is inhibited by cycloheximide. under various conditions of cultivatio ...2002125845
mapping woronin body position in aspergillus nidulans.the positions of all woronin bodies in five germlings of aspergillus nidulans prepared by plunge freezing and freeze substitution were determined by transmission electron microscopy. as expected, woronin bodies were found near septa. high numbers of morphologically identical organelles were also found in apical regions. to verify that these organelles were authentic woronin bodies, we used antibodies raised against the neurospora crassa woronin body matrix protein hex1. anti-hex1 antibodies labe ...200221156495
a point mutation in the two-component histidine kinase bcos-1 gene confers dicarboximide resistance in field isolates of botrytis cinerea.abstract partial dna fragments of botrytis cinerea field isolates encoding the putative osmosensor histidine kinase gene (bcos1) were cloned by polymerase chain reaction amplification and the predicted amino acid sequences were compared between dicarboximide-sensitive and resistant field isolates. the predicted bcos1p is highly homologous to osmosensor histidine kinase os1p from neurospora crassa including the n-terminal six tandem repeats of approximately 90 amino acids. four dicarboximide-resi ...200218944142
primary structure of the histone 2b gene in the white root rot fungus, rosellinia necatrix.the nucleotide sequence of the histone 2b (h2b) gene in the white root rot fungus, rosellinia necatrix, was determined. the gene has two introns in the coding region at positions conserved in the neurospora crassa and aspergillus nidulans h2b genes, but the third intron present in the h2b gene from n. crassa and a. nidulans is absent in the r. necatrix h2b gene. the amino acid sequence of the coding region of the r. necatrix gene resembled that of n. crassa and a. nidulans. therefore, the third ...200212652911
analysis of interactions between domains of a small heat shock protein, hsp30 of neurospora crassa.the alpha-crystallin-related, small heat shock proteins (shsps), despite their overall variability in sequence, have discrete regions of conserved sequence that are involved in structural organization, as well as nonconserved regions that may perform similar roles in each protein. recent x-ray diffraction analyses of an archeal and a plant shsp have revealed both similarities and differences in how they are organized, suggesting that there is variability, particularly in the oligomeric organizat ...200212653482
purification and characterization of the complex i from the respiratory chain of rhodothermus marinus.the rotenone sensitive nadh:menaquinone oxidoreductase (ndh-i or complex i) from the thermohalophilic bacterium rhodothermus marinus has been purified and characterized. three of its subunits react with antibodies against 78, 51, and 21.3c kda subunits of neurospora crassa complex i. the optimum conditions for nadh dehydrogenase activity are 50 degrees c and ph 8.1, and the enzyme presents a km of 9 microm for nadh. the enzyme also displays nadh:quinone oxidoreductase activity with two menaquino ...200212678433
biosynthesis of pyridoxine in saccharomyces cerevisiae--origin of the pyridoxine nitrogen atom differs under anaerobic and aerobic conditions.the amide nitrogen atom of glutamine is incorporated into pyridoxine in four eukaryotes (i.e., emericella nidulans, mucor racemosus, neurospora crassa and saccharomyces cerevisiae) and two prokaryotes (i.e., staphylococcus aureus and bacillus subtilis). however, in the prokaryotes pseudomonas putida, enterobacter aerogenes and escherichia coli, it is the nitrogen atom of glutamate that is incorporated into pyridoxine (j nutr sci vitaminol (2000) 46, 55-57). as these results were from experiments ...200212775110
regulation of expression of the rhizopus oryzae uricase and urease enzymes.the regulation of intracellular urease and uricase activities was examined in rhizopus oryzae. urease activity (2.4 u/mg protein) was present in r. oryzae mycelium grown in minimal medium containing nh4ci as sole nitrogen source. this activity increased threefold under nitrogen derepression conditions, but no induction by urea was detected. control of urease activity in r. oryzae differs from that found in neurospora crassa but resembles the situation in aspergillus nidulans. no uricase activity ...200212619824
amplification of hmg-coa reductase production enhances carotenoid accumulation in neurospora crassa.neurospora crassa, a filamentous fungus, naturally produces the carotenoids lycopene and neurosporaxanthin. to increase the carbon flux through the carotenoid biosynthetic pathway, the 1658-bp region of the hmg1 gene encoding the catalytic domain (chmg1) of 3-hydroxy-3-methylglutaryl coenzyme a (hmg-coa) reductase of saccharomyces cerevisiae was expressed in n. crassa under control of the strong, constitutive glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter and the inducible alcohol dehyd ...200212616689
a new class of tetraspanins in fungi.tetraspanins are animal proteins involved in membrane complexes that are involved in cell adhesion, differentiation, and motility. the pls1 gene from rice blast fungus magnaporthe grisea encodes a protein (pls1p) structurally related to tetraspanins that is required for pathogenicity. in botrytis cinerea public sequences, we identified an est homologous to pls1. using degenerated oligonucleotides, we amplified sequences homologous to pls1 in fungi colletotrichum lindemuthianum and neurospora cra ...200212372414
cloning and sequence analysis of a mitochondrial gene cluster encoding cytochrome c oxidase subunit iii from trichoderma pseudokoningii.a mitochondrial gene cluster encoding cytochrome c oxidase subunit iii (cox3), an orf (called orf250) similar to nadh dehydrogenase subunit vi (nd6), ten trna molecules, partial rrna small subunit and rrna large subunit from trichoderma pseudokoningii s38 was cloned and sequenced. these genes are tandemly clustered on the mitochondrial genome of trichoderma pseudokoningii s38. phylogenetic analysis showed that cytochrome c oxidase subunits iii exhibited high degree of similarity to sequences fro ...200212592707
the oligomeric state, complex formation, and chaperoning activity of hsp70 and hsp80 of neurospora crassa.molecular chaperones perform vital cellular functions under normal growth conditions and protect cells against stress-induced damage. the stress proteins hsp70 and hsp80 of neurospora crassa were extracted from heat-shocked mycelium, purified to near homogeneity, and examined with respect to their oligomeric state, complex formation, and chaperoning properties. their oligomeric state was assessed by dynamic light-scattering measurements, and both hsp70 and hsp80 were observed to form a range of ...200212555813
a new wc-1 mutant of neurospora crassa shows unique light sensitivity in the circadian conidiation rhythm.a new clock mutant ( rhy-2) was isolated by dna insertion mutagenesis using a plasmid that contains a region located upstream of the cmd gene in the genome of neurospora crassa. this mutant is arrhythmic with regard to conidiation in continuous darkness but rhythmic under a light-dark cycle. after plasmid rescue from genomic dna of the rhy-2 strain, the insertion was localized to the gene white collar-1 ( wc-1). plasmid dna was inserted 3' to the sequence encoding the polyglutamine region of the ...200212242499
nonself recognition is mediated by het-c heterocomplex formation during vegetative incompatibility.nonself recognition during vegetative growth in filamentous fungi is mediated by heterokaryon incompatibility (het) loci. in neurospora crassa, het-c is one of 11 het loci. three allelic specificity groups, termed het-c(or), het-c(pa) and het-c(gr), exist in natural populations. heterokaryons or partial diploids that contain het-c alleles of alternative specificity show severe growth inhibition, repression of conidiation and hyphal compartmentation and death (hcd). using epitope-tagged het-c, we ...200212234924
live-cell imaging of vegetative hyphal fusion in neurospora crassa.the process of hyphal fusion (anastomosis) in growing colonies of neurospora crassa, stained with the membrane-selective dyes fm1-43 and fm4-64, was visualized by confocal microscopy. time-lapse, live-cell imaging illustrated the dynamics of hyphal growth and anastomosis during its pre-contact, contact and post-contact, and post-fusion stages. fusion-competent hyphae were morphologically distinct and exhibited remote sensing, resulting in branch initiation and/or re-direction of growth to facili ...200212223195
from nadh to ubiquinone in neurospora mitochondria.the respiratory chain of the mitochondrial inner membrane includes a proton-pumping enzyme, complex i, which catalyses electron transfer from nadh to ubiquinone. this electron pathway occurs through a series of protein-bound prosthetic groups, fmn and around eight iron-sulfur clusters. the high number of polypeptide subunits of mitochondrial complex i, around 40, have a dual genetic origin. neurospora crassa has been a useful genetic model to characterise complex i. the characterisation of mutan ...200212206913
the art and design of genetic screens: filamentous fungi.in the 1940s, screens for metabolic mutants of the filamentous fungus neurospora crassa established the fundamental, one-to-one relationship between a gene and a specific protein, and also established fungi as important genetic organisms. today, a wide range of filamentous species, which represents a billion years of evolutionary divergence, is used for experimental studies. the developmental complexity of these fungi sets them apart from unicellular yeasts, and allows the development of new scr ...200212209143
blue light modulation of ion transport in the slime mutant of neurospora crassa.blue light is the primary entrainment signal for a number of developmental and morphological processes in the lower eucaryote neurospora crassa. blue light regulates photoactivation of carotenoid synthesis, conidiation, phototropism of perithecia and circadian rhythms. changes in the electrical properties of the plasma membrane are one of the fastest responses to blue light irradiation. to enable patch-clamp studies on light-induced ion channel activity, the wall-less slime mutant was used. patc ...200212181612
overexpression of white collar-1 (wc-1) activates circadian clock-associated genes, but is not sufficient to induce most light-regulated gene expression in neurospora crassa.many processes in fungi are regulated by light, but the molecular mechanisms are not well understood. the white collar-1 (wc-1) protein is required for all known blue-light responses in neurospora crassa. in response to light, wc-1 levels increase, and the protein is transiently phosphorylated. to test the hypothesis that the increase in wc-1 levels after light treatment is sufficient to activate light-regulated gene expression, we used microarrays to identify genes that respond to light treatme ...200212180913
the neurospora crassa pheromone precursor genes are regulated by the mating type locus and the circadian clock.pheromones play important roles in female and male behaviour in the filamentous ascomycete fungi. to begin to explore the role of pheromones in mating, we have identified the genes encoding the sex pheromones of the heterothallic species neurospora crassa. one gene, expressed exclusively in mat a strains, encodes a polypeptide containing multiple repeats of a putative pheromone sequence bordered by kex2 processing sites. strains of the opposite mating type, mat a, express a pheromone precursor g ...200212139624
neurospora crassa supersuppressor mutants are amber codon-specific.neurospora crassa has 10 mapped supersuppressor (ssu) genes. in vivo studies indicate that they suppress amber (uag) premature termination mutations but the spectrum of their functions remains to be elucidated. we examined seven ssu strains (ssu-1, -2, -3, -4, -5, -9, and -10) using cell-free translation extracts. we tested suppression by requiring it to produce firefly luciferase from a reading frame containing premature uaa, uga, or uag terminators. all mutants except ssu-3 suppressed uag codo ...200212135572
light reception and circadian behavior in 'blind' and 'clock-less' mutants of neurospora crassa.the filamentous fungus neurospora crassa is a model organism for the genetic dissection of blue light photoreception and circadian rhythms. white collar-1 (wc-1) and wc-2 are considered necessary for all light responses, while frequency (frq) is required for light-regulated asexual development (conidia formation); without any of the three, self-sustained (circadian) rhythmicity in constant conditions fails. here we show that light-regulated and self-sustained development occur in the individual ...200212110577
domain movements of plasma membrane h(+)-atpase: 3d structures of two states by electron cryo-microscopy.h(+)-atpase is a p-type atpase that transports protons across membranes using the energy from atp hydrolysis. this hydrolysis is coupled to a conformational change between states of the protein, in which the proton-binding site is alternately accessible to the two sides of the membrane with an altered affinity. when isolated from neurospora crassa, h(+)-atpase is a 600 kda hexamer of identical 100 kda polypeptides. we have obtained the three-dimensional structures of both ligand-free and mg(2+)/ ...200212110571
white collar-1, a circadian blue light photoreceptor, binding to the frequency promoter.in the fungus neurospora crassa, the blue light photoreceptor(s) and signaling pathway(s) have not been identified. we examined light signaling by exploiting the light sensitivity of the neurospora biological clock, specifically the rapid induction by light of the clock component frequency (frq). light induction of frq is transcriptionally controlled and requires two cis-acting elements (lres) in the frq promoter. both lres are bound by a white collar-1 (wc-1)/white collar-2 (wc-2)-containing co ...200212098706
white collar-1, a dna binding transcription factor and a light sensor.blue light regulates many physiological processes in fungi, but their photoreceptors are not known. in neurospora crassa, all light responses depend on the per-arnt-sim (pas) domain-containing transcription factor white collar-1 (wc-1). by removing the wc-1 light, oxygen, or voltage domain, a specialized pas domain that binds flavin mononucleotide in plant phototropins, we show that light responses are abolished, including light entrainment of the circadian clock. however, the wc-1-mediated dark ...200212098705
a dead-box protein functions as an atp-dependent rna chaperone in group i intron splicing.the neurospora crassa cyt-18 protein, the mitochondrial tyrosyl-trna synthetase, functions in splicing group i introns by inducing formation of the catalytically active rna structure. here, we identified a dead-box protein (cyt-19) that functions in concert with cyt-18 to promote group i intron splicing in vivo and vitro. cyt-19 does not bind specifically to group i intron rnas and instead functions as an atp-dependent rna chaperone to destabilize nonnative rna structures that constitute kinetic ...200212086675
mitochondrial dynamics in filamentous fungi.mitochondria are essential organelles of eukaryotic cells. they grow continuously throughout the cell cycle and are inherited by daughter cells upon cell division. inheritance of mitochondria and maintenance of mitochondrial distribution and morphology require active transport of the organelles along the cytoskeleton and depend on membrane fission and fusion events. many of the molecular components and cellular mechanisms mediating these complex processes have been conserved during evolution acr ...200212081462
protein import into mitochondria of neurospora crassa.biogenesis of mitochondria requires import of several hundreds of different nuclear-encoded preproteins needed for mitochondrial structure and function. import and sorting of these preproteins is a multistep process facilitated by complex proteinaceous machineries located in the mitochondrial outer and inner membranes. the translocase of the mitochondrial outer membrane, the tom complex, comprises receptors which specifically recognize mitochondrial preproteins and a protein conducting channel f ...200212081461
nht2, a copia ltr retrotransposon from a conditionally dispensable chromosome in nectria haematococca.in the plant pathogenic ascomycete nectria haematococca mating population (mp) vi, the conditionally dispensable chromosomes are unstable during sexual reproduction. during mapping of such a chromosome, three dispersed repeats were identified. nht2, one of these repeated elements, is a long terminal repeat (ltr) retrotransposon that is 5.9 kb in length. its deduced amino acid sequence is homologous to the four enzymatic domains characteristic of copia retrotransposons, but it contains multiple s ...200212073091
multilocus self-recognition systems in fungi as a cause of trans-species polymorphism.trans-species polymorphism, meaning the presence of alleles in different species that are more similar to each other than they are to alleles in the same species, has been found at loci associated with vegetative incompatibility in filamentous fungi. if individuals differ at one or more of these loci (termed het for heterokaryon), they cannot form stable heterokaryons after vegetative fusion. at the het-c locus in neurospora crassa and related species there is clear evidence of trans-species pol ...200212072460
circadian period lengths of lipid synthesis mutants (cel, chol-1) of neurospora show defective temperature, but intact ph-compensation.the influence of extracellular ph on the circadian sporulation rhythm of neurospora crassa has been investigated for the mutants chol-1 and cel. both mutants have a defect in the lipid synthesis pathway and require either choline or palmitate, respectively, as supplements for normal growth. the chol-1 and cel mutants also show an impaired temperature-compensation when growing on minimal medium. we investigated the possible correlation between loss of temperature- and ph-compensation in cel and c ...200212069035
an ensemble method for identifying regulatory circuits with special reference to the qa gene cluster of neurospora crassa.a chemical reaction network for the regulation of the quinic acid (qa) gene cluster of neurospora crassa is proposed. an efficient monte carlo method for walking through the parameter space of possible chemical reaction networks is developed to identify an ensemble of deterministic kinetics models with rate constants consistent with rna and protein profiling data. this method was successful in identifying a model ensemble fitting available rna profiling data on the qa gene cluster.200212477937
multiple functions of mfa-1, a putative pheromone precursor gene of neurospora crassa.a putative pheromone precursor gene of neurospora crassa, mfa-1 (which encodes mating factor a-1), was identified as the most abundant clone in starved mycelial and perithecial cdna libraries. northern analysis demonstrated high mfa-1 expression in all mating type a tissues and suggested low expression levels in mat a tissues. the mfa-1 gene was expressed as an approximately 1.2-kb transcript predicted to encode a 24-residue peptide, followed by a long 3' untranslated region (3' utr). the predic ...200212477799
shared and independent roles for a galpha(i) protein and adenylyl cyclase in regulating development and stress responses in neurospora crassa.growth and development are regulated using cyclic amp (camp)-dependent and -independent pathways in neurospora crassa. the cr-1 adenylyl cyclase mutant lacks detectable camp and exhibits numerous defects, including colonial growth habit, short aerial hyphae, premature conidiation on plates, inappropriate conidiation in submerged culture, and increased thermotolerance. evidence suggests that the heterotrimeric galpha protein gna-1 is a direct positive regulator of adenylyl cyclase. deltagna-1 str ...200212456011
neurospora clock-controlled gene 9 (ccg-9) encodes trehalose synthase: circadian regulation of stress responses and development.the circadian clock of neurospora crassa regulates the rhythmic expression of a number of genes encoding diverse functions which, as an ensemble, are adaptive to life in a rhythmic environment of alternating levels of light and dark, warmth and coolness, and dryness and humidity. previous differential screens have identified a number of such genes based solely on their cycling expression, including clock-controlled gene 9 (ccg-9). sequence analysis now shows the predicted ccg-9 polypeptide to be ...200212455969
distinct signaling pathways from the circadian clock participate in regulation of rhythmic conidiospore development in neurospora crassa.several different environmental signals can induce asexual spore development (conidiation) and expression of developmentally regulated genes in neurospora crassa. however, under constant conditions, where no environmental cues for conidiation are present, the endogenous circadian clock in n. crassa promotes daily rhythms in expression of known developmental genes and of conidiation. we anticipated that the same pathway of gene regulation would be followed during clock-controlled conidiation and ...200212455961
morphological alterations induced by cold-shock in neurospora crassa.the effects of cold-shock on neurospora crassa was here investigated. in cold-shock treated hyphae (6 h at 4 degrees c) the branching pattern was changed and dichotomy as well as a fan-like-pattern structure were temporarily detected at the tips. when exogenous ca(2+) (500 mm) was added to the hyphae, these morphological alterations were not detected. in addition, the protein electrophoretic profile of cultures submitted to cold-shock was different from that of cultures kept at 30 degrees c. aft ...200212442300
an ip3-activated ca2+ channel regulates fungal tip growth.hyphal extension in fungi requires a tip-high ca(2+) gradient, which is generated and maintained internally by inositol (1,4,5)-trisphosphate (ip(3))-induced ca(2+) release from tip-localized vesicles and subapical ca(2+) sequestration. using the planar bilayer method we demonstrated the presence of two types of ip(3)-activated ca(2+) channels in neurospora crassa membranes with different conductances: one low (13 picosiemens), the other high (77 picosiemens). on sucrose density gradients the lo ...200212432087
the effects of ropy-1 mutation on cytoplasmic organization and intracellular motility in mature hyphae of neurospora crassa.we have used light and electron microscopy to document the cytoplasmic effects of the ropy (ro-1) mutation in mature hyphae of neurospora crassa and to better understand the role(s) of dynein during hyphal tip growth. based on video-enhanced dic light microscopy, the mature, growing hyphae of n. crassa wild type could be divided into four regions according to cytoplasmic organization and behavior: the apical region (i) and three subapical regions (ii, iii, and iv). a well-defined spitzenkörper d ...200212409101
a fourier transform infrared study of neurospora rhodopsin: similarities with archaeal rhodopsins.the nop-1 gene from the eukaryote neurospora crassa, a filamentous fungus, has recently been shown to encode an archaeal rhodopsin-like protein nop-1. to explore the functional mechanism of nop-1 and its possible similarities to archaeal and visual rhodopsins, static and time-resolved fourier transform infrared difference spectra were measured from wild-type nop-1 and from a mutant containing an asp-->glu substitution in the schiff base (sb) counterion, asp131 (d131e). several conclusions could ...200212403457
minimal promoter for the nad+-specific glutamate dehydrogenase gene of neurospora crassa.the expression of the nad+-specific glutamate dehydrogenase (nad-gdh) gene of neurospora crassa is subject to catabolite repression. to identify the minimal sequence necessary for promoter function, the 5'-flanking region of the nad-gdh gene was screened for potential protein-binding sites. fragments of dna, containing sequences upstream from the atg initiation codon, were employed as probes of southwestern blots of total cellular protein from cells grown in media promoting repression and induct ...200211989713
3-carboxy-cis,cis-muconate lactonizing enzyme from neurospora crassa: mad phasing with 80 selenomethionines.the structure of 3-carboxy-cis,cis-muconate lactonizing enzyme from neurospora crassa was determined at 3.0 a resolution. phase information was derived from a multiwavelength anomalous dispersion (mad) experiment conducted at three wavelengths using crystals of fully substituted selenomethionine protein. however, the structure determination was not routine owing to the relatively poor quality of the diffraction data and the large number of twofolds in the unit cell. eventually, 80 selenium sites ...200211976482
isolation and characterization of tightly coupled mitochondria from wild type and nap mutant neurospora crassa.a fast and reproducible procedure was elaborated for isolation of tightly coupled mitochondria from wild type and nap-mutant neurospora crassa cells harvested at different growth stages. the isolated mitochondrial preparations had controlled metabolic states and were tightly coupled, i.e., displayed good respiratory control and had close to the theoretically expected maximal adp/o ratios upon oxidation of krebs cycle intermediates and exogenous nadh. they contained the fully competent respirator ...200211952424
involvement of small rnas and role of the qde genes in the gene silencing pathway in neurospora.small rna molecules have been found to be specifically associated with posttranscriptional gene silencing (ptgs) in both plants and animals. here, we find that small sense and antisense rnas are also involved in ptgs in neurospora crassa. the accumulation of these rna molecules depends on the presence of functional qde-1 and qde-3 genes previously shown to be essential for gene silencing, but does not depend on a functional qde-2, indicating that this gene is involved in a downstream step of the ...200211937487
the structure of neurospora crassa 3-carboxy-cis,cis-muconate lactonizing enzyme, a beta propeller cycloisomerase.muconate lactonizing enzymes (mles) convert cis,cis-muconates to muconolactones in microbes as part of the beta-ketoadipate pathway; some also dehalogenate muconate derivatives of xenobiotic haloaromatics. there are three different mle classes unrelated by evolution. we present the x-ray structure of a eukaryotic mle, neurospora crassa 3-carboxy-cis,cis-muconate lactonizing enzyme (nccmle) at 2.5 a resolution, with a seven-bladed beta propeller fold. it is related neither to bacterial mles nor t ...200211937053
quelling in neurospora crassa. 200211931228
transformation in heterokaryons of neurospora crassa is nuclear rather than cellular phenomenon.in neurospora crassa, multinucleate macroconidia are used for genetic transformation. the barrier for such a transformation can be either at the cell membrane level or at the nuclear membrane level. for assessment of these possibilities, a forced heterokaryon (containing two genetically marked nuclei and auxotrophic for histidine) of neurospora crassa was transformed with a plasmid containing his-3+ gene. the transformants, which could grow without histidine supplementation, were then resolved i ...200211927980
the many faces of histone lysine methylation.diverse post-translational modifications of histone amino termini represent an important epigenetic mechanism for the organisation of chromatin structure and the regulation of gene activity. within the past two years, great progress has been made in understanding the functional implications of histone methylation; in particular through the characterisation of histone methyltransferases that direct the site-specific methylation of, for example, lysine 9 and lysine 4 positions in the histone h3 am ...200212067650
mutations in subunit c of the vacuolar atpase confer resistance to bafilomycin and identify a conserved antibiotic binding site.bafilomycin a1, a potent inhibitor of vacuolar h(+)-atpases (v-atpase), inhibited growth of neurospora crassa in medium adjusted to alkaline ph. ninety-eight mutant strains were selected for growth on medium (ph 7.2) containing 0.3 or 1.0 microm bafilomycin. three criteria suggested that 11 mutant strains were altered in the v-atpase: 1) these strains accumulated high amounts of arginine when grown at ph 5.8 in the presence of bafilomycin, 2) the mutation mapped to the locus of vma-3, which enco ...200211724795
fertile hypomorphic argonaute (ago1) mutants impaired in post-transcriptional gene silencing and virus resistance.transgene-induced post-transcriptional gene silencing (ptgs) results from specific degradation of rnas that are homologous with the transgene transcribed sequence. this phenomenon, also known as cosuppression in plants and quelling in fungi, resembles rna interference (rnai) in animals. indeed, cosuppression/quelling/rnai require related paz/piwi proteins (ago1/qde-2/rde-1), indicating that these mechanisms are related. unlike neurospora crassa qde-2 and caenorhabditis elegans rde-1 mutants, whi ...200211910010
control of cpnpg dna methylation by the kryptonite histone h3 methyltransferase.gene silencing in eukaryotes is associated with the formation of heterochromatin, a complex of proteins and dna that block transcription. heterochromatin is characterized by the methylation of cytosine nucleotides of the dna, the methylation of histone h3 at lysine 9 (h3 lys 9), and the specific binding of heterochromatin protein 1 (hp1) to methylated h3 lys 9 (refs 1-7). although the relationship between these chromatin modifications is generally unknown, in the fungus neurospora crassa, dna me ...200211898023
the reverse transcriptase of the r2 non-ltr retrotransposon: continuous synthesis of cdna on non-continuous rna templates.r2 is a non-long terminal repeat (non-ltr) retrotransposon that inserts into the 28 s rrna genes of arthropods. the element encodes two enzymatic activities: an endonuclease that specifically cleaves the 28 s gene target site, and a reverse transcriptase (rt) that can use the 3' end of the cleaved dna to prime reverse transcription. r2 rt only utilizes rna templates that contain the 3' untranslated region of the r2 element as templates in this target primed reverse transcription (tprt) reaction. ...200211866511
molecular dissection of alleles of the osmotic-1 locus of neurospora crassa.two-component histidine kinases of bacteria, plants, and fungi are involved in the regulation of intracellular events in response to changes in external environmental conditions. fungal histidine kinases play important roles in osmoregulation, in vivo and in planta virulence, and sensitivity to certain classes of antifungals. the osmotic-1 (os-1) locus of neurospora crassa encodes a predicted protein with homology to histidine kinases and appears to be an osmosensor. mutants of the os-1 locus ar ...200211848677
the opposed effect of 5-azacytidine and light on the development of reproductive structures in neurospora crassa.blue light inhibits the formation of asexual cycle spores (conidia) and stimulates the development of the sexual (female) reproductive structures (protoperithecia) in the nitrogen-starved mycelium of neurospora crassa. the dna methylation inhibitor, 5-azacytidine (3-300 microm), opposed the effect of light by suppressing the protoperithecia formation and stimulating a conidiation. the addition of 300 microm 5-azacytidine inhibited protoperithecia formation in the dark-cultivated mycelium by abou ...200211841042
the sterol c-14 reductase encoded by the neurospora crassa erg-3 gene: essential charged and polar residues identified by site-specific mutagenesis.sterol c-14 reductase catalyses the reduction of the delta(14,15) bond in intermediates in the sterol biosynthesis pathway using nadph as a cofactor. we have undertaken a systematic site-directed mutational analysis of all the conserved charged and potentially proton-donating residues of the sterol c-14 reductase from neurospora crassa. the effect of each mutation was determined using an in vivo assay based on the complementation of the corresponding n. crassa mutant ( erg-3). the non-complement ...200211810252
the ham-2 locus, encoding a putative transmembrane protein, is required for hyphal fusion in neurospora crassa.somatic cell fusion is common during organogenesis in multicellular eukaryotes, although the molecular mechanism of cell fusion is poorly understood. in filamentous fungi, somatic cell fusion occurs during vegetative growth. filamentous fungi grow as multinucleate hyphal tubes that undergo frequent hyphal fusion (anastomosis) during colony expansion, resulting in the formation of a hyphal network. the molecular mechanism of the hyphal fusion process and the role of networked hyphae in the growth ...200211805054
large scale analysis of sequences from neurospora crassa.after 50 years of analysing neurospora crassa genes one by one large scale sequence analysis has increased the number of accessible genes tremendously in the last few years. being the only filamentous fungus for which a comprehensive genomic sequence database is publicly accessible n. crassa serves as the model for this important group of microorganisms. the mips n. crassa database currently holds more than 16 mb of non-redundant data of the chromosomes ii and v analysed by the german neurospora ...200211792448
a pest-like element in frequency determines the length of the circadian period in neurospora crassa.frequency (frq) is a crucial element of the circadian clock in neurospora crassa. in the course of a circadian day frq is successively phosphorylated and degraded. here we report that two pest-like elements in frq, pest-1 and pest-2, are phosphorylated in vitro by recombinant ck-1a and ck-1b, two newly identified neurospora homologs of casein kinase 1 epsilon. ck-1a is localized in the cytosol and the nuclei of neurospora and it is in a complex with frq in vivo. deletion of pest-1 results in hyp ...200111742984
epigenetic crosstalk.in the november 15 issue of nature, report that disruption of histone methylation in the fungus neurospora crassa results in the elimination of dna methylation. this demonstrates that chromatin structure can pattern dna methylation and suggests that different epigenetic layers engage in complex crosstalk.200111741529
elimination of active tad elements during the sexual phase of the neurospora crassa life cycle.tad is an active line-like retrotransposon isolated from the adiopodoumé strain of neurospora crassa. extensive analysis of other neurospora strains has revealed no other strain with active tad, but all strains tested have multiple copies of defective tad elements. we have examined the ability of tad to survive during the sexual cycle of neurospora and find that active tad is rapidly eliminated. the characteristics of this elimination suggest that the repeat-induced point mutation (rip) mechanis ...200111407885
characterization of mutations in the two-component histidine kinase gene that confer fludioxonil resistance and osmotic sensitivity in the os-1 mutants of neurospora crassa.osmotic-sensitive (os-1) mutant alleles in neurospora crassa exhibit resistance to dicarboximides, aromatic hydrocarbons and phenylpyrroles. we have previously reported that the os-1 mutants can be classified into two groups based on their resistance to fungicides and osmotic stress: type i, which are highly resistant to iprodione and fludioxonil but moderately sensitive to osmotic stress, and type ii, which are highly sensitive to osmotic stress but moderately resistant to fungicides. to explai ...200111374161
mobilisation of trehalose in mutants of the cyclic amp signalling pathway, cr-1 (crisp-1) and mcb (microcycle conidiation), of neurospora crassa.the influence of the camp-signalling pathway on the metabolism of trehalose in neurospora crassa was investigated. the changes in intracellular trehalose concentration were measured in two mutants affected in components of the camp-signalling pathway: cr-1 (crisp-1), deficient in adenylyl cyclase activity, and mcb (microcyclic conidiation), deficient in the regulatory subunit of pka. rapid mobilisation of intracellular trehalose in the wild-type occurred, either at the onset of germination, or a ...200111356572
vvd is required for light adaptation of conidiation-specific genes of neurospora crassa, but not circadian conidiation.con-10 and con-6 are two of the conidiation (con) genes of neurospora crassa that were identified based on their preferential expression during macroconidiophore development. they are also regulated by several other environmental stimuli independent of development, including a transient induction by light. we identified an allele of vivid (vvd) in a mutant screen designed to obtain strains with altered expression of con-10. vvd mutants display enhanced carotenoid pigmentation in response to ligh ...200111343403
interaction of the neurospora crassa mitochondrial tyrosyl-trna synthetase (cyt-18 protein) with the group i intron p4-p6 domain. thermodynamic analysis and the role of metal ions.the neurospora crassa mitochondrial tyrosyl-trna synthetase (cyt-18 protein) functions in splicing group i introns by promoting the formation of the catalytically active structure of the intron's catalytic core. previous studies suggested a model in which the protein binds first to the intron's p4-p6 domain, and then makes additional contacts with the p3-p9 domain to stabilize the two domains in the correct relative orientation to form the intron's active site. here, we analyzed the interaction ...200111327760
Displaying items 1701 - 1800 of 5889