the topology of vdac as probed by biotin modification.the outer membrane of mitochondria contains channels called vdac (mitochondrial porin), which are formed by a single 30-kda protein. cysteine residues introduced by site-directed mutagenesis at sites throughout neurospora crassa vdac (naturally devoid of cysteine) were specifically biotinylated prior to reconstitution into planar phospholipid membranes. from previous studies, binding of streptavidin to single biotinylated sites results in one of two effects: reduced single-channel conductance wi ...19989733730
the alkaline single cell gel electrophoresis: a new test for assessing dna single strand breaks in neurospora crassa.the single cell gel electrophoresis (comet assay) is a potent technique in testing double and single strand breaks in dna. in this paper, we present an application of alkaline comet assay to filamentous fungi for genotoxicological assessment of heavy metals for the first time. a wild strain of neurospora crassa sla 4200 was grown in presence of cadmium sulfate (cdso4) (10 microm and 100 microm) for 12 h. protoplasts from 12-h old mycelia were prepared by using novozym 234 and dna damage was eval ...19989729255
regulation of pectic enzymes from the exo-1 mutant strain of neurospora crassa: effects of glucose, galactose, and galacturonic acid.the exo-1 mutant of neurospora crassa produced and secreted pectolytic activities when incubated in the presence of pectin-containing biological materials. this study shows that polygalacturonase, pectate lyase and pectin lyase activities were induced in media supplemented with galactose or galacturonic acid, indicating that these sugars induced the synthesis of pectinases. pectinesterase activity was undetectable. polygalacturonase activity was better induced by galactose than by galacturonic a ...19989726123
roles in dimerization and blue light photoresponse of the pas and lov domains of neurospora crassa white collar proteins.the genes coding for white collar-1 and white collar-2 (wc-1 and wc-2) have been isolated previously, and their products characterized as zn-finger transcription factors involved in the control of blue light-induced genes. here, we show that the pas dimerization domains present in both proteins enable the wc-1 and wc-2 proteins to dimerize in vitro. homodimers and heterodimers are formed between the white collar (wc) proteins. a computer analysis of wc-1 reveals a second domain, called lov, also ...19989723912
choline depletion, frq mutations, and temperature compensation of the circadian rhythm in neurospora the fungus neurospora crassa, the chol-1 mutation blocks the synthesis of the lipid phosphatidylcholine and also lengthens the period of the circadian rhythm of conidiation under conditions of choline depletion. the frq mutations, which have no known metabolic defect, affect both the period of the rhythm and temperature compensation. in this article, the chol-1 mutant strain has been further characterized with respect to its temperature compensation and its interactions with frq. choline depl ...19989711502
the chlamydomonas reinhardtii moco carrier protein is multimeric and stabilizes molybdopterin cofactor in a molybdate charged chlamydomonas reinhardtii, molybdopterin cofactor (moco) able to reconstitute active nitrate reductase (nr) with apoenzyme from the neurospora crassa mutant nit-1 was found mostly bound to a carrier protein (cp). this protein is scarce in the algal free extracts and has been purified 520-fold. mococp is a protein of 64 kda with subunits of 16.5 kda and an isoelectric point of 4.5. in contrast to free moco, moco bound to cp was remarkably protected against inactivation under both aerobic condi ...19989708903
apolar growth of neurospora crassa leads to increased secretion of extracellular proteins.protein secretion in filamentous fungi has been shown to be restricted to actively growing hyphal tips. to determine whether an increase in the amount f growing surface area of a fungus can lead to an increase in the amount of protein secretion, we examined secretion in a temperature-sensitive neurospora crassa mcb mutant that shows a loss of growth polarity when incubated at restrictive temperature. incubation of the mcb mutant at restrictive temperature results in a three- to fivefold increase ...19989701815
changes in fatty acid composition of neurospora crassa accompany sexual development and ascospore germination.fatty acid composition was determined during several stages of sexual development in neurospora crassa. triacylglycerol was the predominant acyl lipid in cultures undergoing sexual development. the absolute amounts of triacylglycerol in fertilized cultures varied over time, in contrast to control (unfertilized or mock-fertilized) cultures, in which the amount of triacylglycerol decreased linearly with age. in cultures competent to undergo sexual development, alpha-linoleate was the predominant f ...19989695905
photoregulation of cot-1, a kinase-encoding gene involved in hyphal growth in neurospora light plays a key role as an environmental signal in the regulation of growth and development of fungi and plants. here we demonstrate that in neurospora crassa hyphae branch more frequently in cultures grown in light. previous studies had identified cot-1 as a gene that controls apical hyphal cell elongation. in the cot-1 mutant, cessation of elongation is accompanied by hyperbranching. here we demonstrate that the cot-1 gene encodes two transcript species of about 2100 nt (cot-1 (s)) and ...19989693026
isolation and characterization of strains defective in vacuolar ornithine permease in neurospora crassa.vacuolar uptake of ornithine and lysine was characterized in neurospora crassa using a cupric ion permeabilization system. michaelis constants were measured as 1.4 mm for lysine and 11.0 mm for ornithine, and maximal velocities were determined. vacuolar lysine uptake was shown to be inhibited competitively by l-arginine and histidine while ornithine uptake was inhibited by a variety of amino acids. strains defective in the vacuolar ornithine permease were isolated using a filtration enrichment m ...19989693025
analysis of a distal cluster of binding elements and other unusual features of the promoter of the highly regulated nit-3 gene of neurospora neurospora crassa, the expression of the nit-3 gene (nitrate reductase) is dependent upon nitrogen derepression and nitrate induction and is regulated by two positive-acting transcription factors, nit2 and nit4, and a negative regulator, nmr. the presence of a tightly linked cluster of nit2 and nit4 binding sites suggested that their close spacing might be required for a synergistic interaction of the nit2 and nit4 proteins. we show here that the nit2 and nit4 binding sites can be separated w ...19989693010
a methylated neurospora 5s rrna pseudogene contains a transposable element inactivated by repeat-induced point an analysis of 22 of the roughly 100 dispersed 5s rrna genes in neurospora crassa, a methylated 5s rrna pseudogene, psi63, was identified. we characterized the psi63 region to better understand the control and function of dna methylation. the 120-bp 5s rrna-like region of psi63 is interrupted by a 1.9-kb insertion that has characteristics of sequences that have been modified by repeat-induced point mutation (rip). we found sequences related to this insertion in wild-type strains of n. crassa ...19989691037
trichostatin a causes selective loss of dna methylation in neurospora.both dna methylation and hypoacetylation of core histones are frequently associated with repression of gene expression. possible connections between these processes were investigated by taking advantage of genes controlled by methylation in neurospora crassa. trichostatin a (tsa), a potent inhibitor of histone deacetylase, derepressed a copy of hph that was repressed by dna methylation which resulted from repeat-induced point mutation (rip) acting on sequences flanking hph. derepression by tsa w ...19989689097
analysis of conversion tracts associated with recombination events at the am locus of neurospora cross b163, heteroallelic am1 am6 and heterozygous for both conventional genetic flanking markers and closer molecular markers, we previously found that the majority on flanker exchanges were remote from events that generated prototrophic recombinants. we report here that natural polymorphisms distinguishing the parents of cross b163 also include sequences within and closely flanking am. segregation of these markers in b163 prototrophs confirms that the majority of meiotic recombination event ...19989683674
heat shock effects on second messenger systems of neurospora crassa.exposure of growing hyphae of neurospora crassa to heat shock (44 degrees c) or ethanol (2.6 m) for 1 h induced a significant increase in the camp level, which reached a maximum approximately 2 min after the beginning of treatment and then decreased to control values despite continued heat or ethanol exposure. a 10-s heat shock or a 5-s ethanol shock also resulted in a transient camp increase 2 min after the pulse. heat shock or ethanol treatment led to an increase in the amount of catalytic sub ...19989683659
photoregulation of cot-1, a kinase-encoding gene involved in hyphal growth in neurospora light plays a key role as an environmental signal in the regulation of growth and development of fungi and plants. here we demonstrate that in neurospora crassa hyphae branch more frequently in cultures grown in light. previous studies had identified cot-1 as a gene that controls apical hyphal cell elongation. in the cot-1 mutant, cessation of elongation is accompanied by hyperbranching. here we demonstrate that the cot-1 gene encodes two transcript species of about 2100 nt (cot-1 (s)) and ...19989680960
tissue-specific repression of starvation and stress responses of the neurospora crassa con-10 gene is mediated by rco1.the neurospora crassa con-10 gene is weakly expressed in mycelia but is induced approximately 1000-fold during macroconidiation. studies of the promoter elements and trans-acting factors that regulate con-10 expression are needed to gain a detailed understanding of developmental regulation. the rco-1 mutant displays a 10-fold elevated basal level of expression of con-10. in contrast to the wild type, con-10 expression in mycelia of the rco-1 mutant was rapidly induced to high levels by starvatio ...19989680957
analysis of two transcription activation elements in the promoter of the developmentally regulated con-10 gene of neurospora crassa.the con-10 gene of neurospora crassa is activated during conidiation. crs-b (conidiation response sequence-b) and cge (con-10 general enhancer) elements have been proposed to function as sites of transcriptional activation and as possible elements that confer developmental regulation to con-10. in a specific analysis of the roles of these elements we found that two crs-b elements are necessary for full activation of con-10 during macroconidiation, whereas two cge elements are functionally redund ...19989680956
calcineurin subunit b is required for normal vegetative growth in neurospora crassa.a series of neurospora crassa mutants affected in the ability to regulate entry into conidiation (an asexual developmental program) were isolated by using an insertional mutagenesis procedure followed by a screening protocol. one of the mutants isolated by this approach consisted entirely of cells with an abnormal morphology. the mutant produces chains of swollen septated cells. the developmentally regulated ccg-1 gene is constitutively expressed in these cells, suggesting that they have entered ...19989680955
pleiotropic deficiencies of the laccase-derepressed mutant lah-1 are caused by constitutively increased expression of the cross-pathway control gene cpc-1 in neurospora neurospora crassa, expression of the laccase gene is induced by treatment with the protein synthesis inhibitor cycloheximide (chx). this expression is mediated by cpc1, which acts as a general transcriptional activator when mycelia are treated with chx or starved for any one of the amino acids. a laccase-derepressed mutant, lah-1, shows pleiotropic deficiencies in growth, hyphal morphology, chx sensitivity, and production of protoperithecia. moreover, in the lah-1 mutant, transcript levels of ...19989671030
the membrane domain of complex i is not assembled in the stopper mutant e35 of neurospora.the assembly of mitochondrial nadh: ubiquinone oxidoreductase (complex i) was studied in the e35 stopper mutant of neurospora crassa at different times during growth in liquid media. assembly of complex i as well as of its membrane domain is impaired in this strain throughout the growth period. nevertheless, a structure that resembles the peripheral aim of the enzyme is still formed in the mitochondria of this mutant. the absence of the membrane domain of complex i in e35 can be attributed to th ...19989666316
analysis of complex formation between hsp80 and hsp70, cytosolic molecular chaperones of neurospora crassa, by enzyme-linked immunosorbent assays (elisa).a physical association between hsp70 and hsp80, the major cytosolic stress proteins of neurospora crassa, was demonstrated previously by interprotein crosslinking and by binding of hsp80 to hsp70 immobilized on atp-agarose. in the present study, [hsp70: hsp80] complex formation was analyzed by enzyme-linked immunosorbent assays (elisa), using specific antibodies. one protein was fixed onto elisa plate wells and binding of the second mobile protein was monitored by retention of its cognate igg. b ...19989666311
the preprotein translocation channel of the outer membrane of mitochondria.the preprotein translocase of the outer membrane of mitochondria (tom complex) facilitates the recognition, insertion, and translocation of nuclear-encoded mitochondrial preproteins. we have purified the tom complex from neurospora crassa and analyzed its composition and functional properties. the tom complex contains a cation-selective high-conductance channel. upon reconstitution into liposomes, it mediates integration of proteins into and translocation across the lipid bilayer. tom complex pa ...19989635430
dab1: a degenerate retrotransposon-like element from neurospora crassa.a repeated dna sequence in the genome of neurospora crassa has been identified as a family of degenerate retroelements. retroelements encode protein sequences with clear homology to the reverse transcriptase, rnase h and endonuclease products of the pol genes common to retroviruses and retrotransposons. these sequence comparisons place the n. crassa element within the gypsy group of retrotransposons, akin to other elements found in filamentous fungi. however, the neurospora element is defective, ...19989648750
interaction between major nitrogen regulatory protein nit2 and pathway-specific regulatory factor nit4 is required for their synergistic activation of gene expression in neurospora neurospora crassa, the major nitrogen regulatory protein, nit2, a member of the gata family of transcription factors, controls positively the expression of numerous genes which specify nitrogen catabolic enzymes. expression of the highly regulated structural gene nit-3, which encodes nitrate reductase, is dependent upon a synergistic interaction of nit2 with a pathway-specific control protein, nit4, a member of the gal4 family of fungal regulatory factors. the nit2 and nit4 proteins both bind ...19989632783
analysis of models involving enzymatic activities for the occurrence of c-->t transition mutations during repeat-induced point mutation (rip) in neurospora crassa.the phenomenon of repeat-induced point mutation (rip), acting during the sexual phase of the model eukaryote neurospora crassa, is considered to study the putative in vivo relationships existing between cellular levels of s-adenosylmethionine (sam), cytosine methylation and the occurrence of c-->t transition mutations. we analyse the kinetic behaviour of the different enzymatic models proposed to explain the underlying mutagenic mechanisms of rip. the dependence of the mutation rate on the cellu ...19989628839
characterization of an 88-kda heat shock protein of neurospora crassa that interacts with hsp30.the small heat shock protein of neurospora crassa, hsp30, when employed in affinity chromatography, bound two cellular proteins that were identified as hsp70 and hsp88. both hsp70 and hsp88 bound to hsp30 in preference to other proteins, but binding of hsp88 was more selective for hsp30, and a direct interaction was observed. transcripts for hsp88, a newly characterized protein, are present at normal temperature, but they are strongly induced by heat shock. its cdna sequence predicts a protein w ...19989556627
interactions of chaperone alpha-crystallin with the molten globule state of xylose reductase. implications for reconstitution of the active enzyme.alpha-crystallin is a multimeric protein that has been shown to function as a molecular chaperone. present investigations were undertaken to understand its mechanism of chaperoning. for this functional in vitro analysis of alpha-crystallin we used xylose reductase (xr) from neurospora crassa as the model system. denaturation studies using the structure-perturbing agent guanidinium chloride indicated that xr folds through a partially folded state that resembles the molten globule. fluorescence an ...19989545266
molecular coevolution within a drosophila clock gene.the period (per) gene in drosophila melanogaster provides an integral component of biological rhythmicity and encodes a protein that includes a repetitive threonine-glycine (thr-gly) tract. similar repeats are found in the frq and wc2 clock genes of neurospora crassa and in the mammalian per homologues, but their circadian functions are unknown. in drosophilids, the length of the thr-gly repeat varies widely between species, and sequence comparisons have suggested that the repeat length coevolve ...19989539762
processing and function of a polyprotein precursor of two mitochondrial proteins in neurospora neurospora crassa, the mitochondrial arginine biosynthetic enzymes, n-acetylglutamate kinase (agk) and n-acetyl-gamma-glutamyl-phosphate reductase (agpr), are generated by processing of a 96-kda cytosolic polyprotein precursor (pagk-agpr). the proximal kinase and distal reductase domains are separated by a short connector region. substitutions of arginines at positions -2 and -3 upstream of the n terminus of the agpr domain or replacement of threonine at position +3 in the mature agpr domain ...19989525895
three-dimensional map of the plasma membrane h+-atpase in the open conformation.the h+-atpase from the plasma membrane of neurospora crassa is an integral membrane protein of relative molecular mass 100k, which belongs to the p-type atpase family that includes the plasma membrane na+/k+-atpase and the sarcoplasmic reticulum ca2+-atpase. the h+-atpase pumps protons across the cell's plasma membrane using atp as an energy source, generating a membrane potential in excess of 200mv. despite the importance of p-type atpases in controlling membrane potential and intracellular ion ...19989572146
conversion of palmitate to unsaturated fatty acids differs in a neurospora crassa mutant with impaired fatty acid synthase activity.the neurospora crassa cel (fatty acid chain elongation) mutant has impaired fatty acid synthase activity. the cel mutant requires exogenous 16:0 for growth and converts 16:0 to other fatty acids. in contrast to wild-type n. crassa, which converted only 42% of the exogenous [7,7,8,8-(2)h4]16:0 that was incorporated into cell lipids to unsaturated fatty acids, cel converted 72%. in addition, cel contains higher levels of 18:3(delta 9,12,15) than wild-type, and synthesizes two fatty acids, 20:2(del ...19989560805
characterization of mat a-2, mat a-3 and deltamata mating-type mutants of neurospora crassa.the mating-type locus of neurospora crassa regulates mating identity and entry into the sexual cycle. the mat a idiomorph encodes three genes, mat a-1, mat a-2, and mat a-3. mutations in mat a-1 result in strains that have lost mating identity and vegetative incompatibility with mat a strains. a strain containing mutations in both mat a-2 and mat a-3 is able to mate, but forms few ascospores. in this study, we describe the isolation and characterization of a mutant deleted for mat (deltamata), a ...19989539425
inactivation of the gene coding for the 30.4-kda subunit of respiratory chain nadh dehydrogenase: is the enzyme essential for neurospora?we have isolated and characterised the nuclear gene that codes for the 30.4-kda subunit of the peripheral arm of complex i from neurospora crassa. the single-copy gene was localised on chromosome vi of the fungal genome by restriction fragment length polymorphism mapping. an extra copy of the gene was introduced into a strain of n. crassa by transformation. this strain was crossed with another strain in order to inactivate, by repeat-induced point mutations, both copies of the duplication carrie ...19989520272
microscopic and ultrastructural examination of vegetative incompatibility in partial diploids heterozygous at het loci in neurospora crassavegetative (or heterokaryon) incompatibility is often characterized by cell death after anastomosis. in neurospora crassa, partial diploid strains heterozygous for a single heterokaryon incompatibility (het) gene are viable, but grow at a significantly inhibited rate. strains heterozygous for het-6 or het-c were examined microscopically for evidence of cell death; approximately 15% of cells randomly distributed within such colonies were dead or dying. electron microscopy revealed extensive organ ...19989514694
purification, characterization, and mechanism of a flavin mononucleotide-dependent 2-nitropropane dioxygenase from neurospora crassa.a nitroalkane-oxidizing enzyme was purified to homogeneity from neurospora crassa. the enzyme is composed of two subunits; the molecular weight of each subunit is approximately 40,000. the enzyme catalyzes the oxidation of nitroalkanes to produce the corresponding carbonyl compounds. it acts on 2-nitropropane better than on nitroethane and 1-nitropropane, and anionic forms of nitroalkanes are much better substrates than are neutral forms. the enzyme does not act on aromatic compounds. when the e ...19989501443
characterization of vacuolar arginine uptake and amino acid efflux in neurospora crassa using cupric ion to permeabilize the plasma membrane.treatment of neurospora crassa mycelia with cupric ion has been shown to permeabilize the plasma and mitochondrial membranes. permeabilized mycelia were shown to take up arginine into the vacuoles. uptake was atp-independent and appeared to be driven by an existing k+-gradient. the kinetic characteristics of the observed uptake were similar to those observed using vacuolar membrane vesicles: the km for arginine uptake was found to be 4.2-4.5 mm. permeabilized mycelia were used to study the regul ...19979454645
blue light regulation in neurospora crassa.the fungus neurospora crassa has been shown to be a paradigm for photobiological, biochemical, and genetic studies of blue light perception and signal transduction. several different developmental and morphological processes of neurospora are regulated by blue light and can be divided into early and late blue light responses. the characterization of two central regulator proteins of blue light signal transduction in neurospora crassa, wc1 and wc2, and the isolation of light-regulated genes, indi ...19979454641
long, interrupted conversion tracts initiated by cog in neurospora crassa.multiple polymorphisms distinguish emerson and lindegren strains of neurospora crassa within the histidine-3 gene and in its distal flank. restriction site and sequence length polymorphism in a set of 14 pcr products covering this 6.9-kb region were used to identify the parental origin of dna sequence information in prototrophic progeny of crosses heterozygous for auxotrophic mutations in his-3 and the silent sequence differences. forty-one percent of conversion tracts are interrupted. where the ...19989475725
homology modeling of neurospora crassa geranylgeranyl pyrophosphate synthase: structural interpretation of mutant phenotypes.a model of the tertiary structure of the neurospora crassa carotenogenic prenyltransferase, geranylgeranyl pyrophosphate synthase (ggpps), is presented, based on structural homology with other prenyltransferases and on the crystal structure of recombinant avian farnesyl pyrophosphate synthase (fpps). the conserved aspartate-rich motifs ddxx(xx)d and associated basic residues, considered to be the active sites for binding and catalysis in all prenyltransferases, are highly conserved in the n. cra ...19979464568
cloning and characterization of the gene encoding beta subunit of mitochondrial processing peptidase from the basidiomycete lentinula edodes.we have isolated the gene encoding the beta subunit of mitochondrial processing peptidase (beta-mpp) from the shiitake mushroom lentinula edodes. it is a nuclear gene with two small introns. comparison with known beta-mpp genes revealed that the l. edodes gene is most closely related with that from neurospora crassa, with 60.8% identities and 87% similarity in the amino-acid sequences. the deduced l. edodes beta-mpp peptide sequence contains the inverse zinc-binding motif (h-x-e-h) that has been ...19989461410
effects of the tol mutation on allelic interactions at het loci in neurospora crassa.a mutant at the tol locus of neurospora crassa can suppress heterokaryon (vegetative) incompatibility associated with differences at the mating-type locus. we tested the ability of this allele to suppress the vegetative incompatibility reactions that can occur when strains differ at one of nine het loci (het-c, -d, -e, -5, -6, -7, -8, -9, and -10). we found no cases in which the tol mutant suppresses a heteroallelic het locus interaction. thus, the interaction(s) that leads to vegetative incompa ...19979449795
specific, high affinity binding sites for an antifungal plant defensin on neurospora crassa hyphae and microsomal membranes.hs-afp1, an antifungal plant defensin from seed of the plant heuchera sanguinea, was radioactively labeled using t-butoxycarbonyl-[35s]l-methionine n-hydroxysuccinimidyl ester, resulting in a 35s-labeled peptide with unaltered antifungal activity. [35s]hs-afp1 was used to assess binding on living hyphae of the fungus neurospora crassa. binding of [35s]hs-afp1 was found to be competitive, reversible, and saturable with an apparent kd of 29 nm and a bmax of 1.4 pmol/mg protein. [35s]hs-afp1 also b ...19979405418
genetic analysis of signal transduction through light-induced protein phosphorylation in neurospora crassa perithecia.we have previously demonstrated that blue light induces the phosphorylation of a 15-kda protein in crude membrane fractions of neurospora crassa mycelia. here we report the isolation and characterization of a mutant (psp; phosphorylation of small proteins that is completely defective for phosphorylation of that protein, as assayed in both crude membrane and soluble fractions. this mutation defines a unique locus that maps to linkage group vr between al-3 and his-6. to elucidate the photobiologic ...19979435784
two distinct protein-protein interactions between the nit2 and nmr regulatory proteins are required to establish nitrogen metabolite repression in neurospora crassa.nitrogen metabolism is a highly regulated process in neurospora crassa. the structural genes that encode nitrogen catabolic enzymes are subject to nitrogen metabolite repression, mediated by the positive-acting nit2 protein and by the negative-acting nmr protein. nit2, a globally acting factor, is a member of the gata family of regulatory proteins and has a single cys2/cys2 zinc finger dna-binding domain. the negative-acting nmr protein interacts via specific protein-protein binding with two dis ...19979427402
purification and some molecular properties of rice germ calmodulin.calmodulin (cam) from rice germ (oryza sativa l) was purified to homogeneity by hydrophobic interaction chromatography and gel filtration. the protein showed a single spot by sds-page. this purified protein had multiple absorption maxima at 276~279, 268, 265, 258, and 253 nm. like other plant cam, the protein contained one mole of tm3lys, cysteine, and tyrosine, and tryptophan was not detected. hydrophobic properties of rice germ, spinach, and neurospora crassa cam were directly tested by an hpl ...199827388650
white collar proteins: passing the light signal in neurospora crassa.the filamentous fungus neurospora crassa is an excellent paradigm for the study of blue light signal transduction. the isolation and characterization of the genes for two central regulators of the blue light response, white collar-1 and white collar-2, have begun to shed light on the mechanism of blue light signal transduction in fungi. these proteins are not only proposed to encode blue-light-activated transcription factors but also to be elements of the blue light signal transduction pathway.19979402704
differential hsc70 expression during asexual development of neurospora crassa.the constitutive and the heat-shock-induced expression of members of heat-shock protein families changed during vegetative development and conidiation of neurospora crassa as determined by two-dimensional gel electrophoresis. western blot and elisa analyses revealed the highest amounts of the constitutive heat-shock protein 70 (hsc70) in conidiating aerial hyphae and dormant conidia. during conidial germination the amount of hsc70 decreased and subsequently increased during vegetative growth. st ...19979387240
site and significance of cysteine residues in xylose reductase from neurospora crassa as deduced by fluorescence studies.inactivation of xylose reductase (xr) by p-hydroxy-mercury benzoate (phmb) was found to be biphasic with second-order rate constants of 80 and 6 m-1s-1 for the fast (kf) and slow (ks) phase respectively. spectroscopic studies indicated that the inactivation was due to modification of one cys residue per molecule of xr and not due to subsequent disruption of the quaternary structure. the binding of nadph to xr (kd 0.9 microm) was depressed on modification of the enzyme by phmb (kd 2.3 microm). th ...19979367847
primary structure of neurospora crassa gamma-tubulin.we report the isolation and characterization of a cdna-clone for gamma-tubulin from n. crassa. the deduced amino-acid sequence of the cdna-clone most resembles that of gamma-tubulins from other fungi. differential southern blot analysis demonstrates that most probably a single gene represents gamma-tubulin. in addition, northern blot analysis shows that most probably only one single mrna encoding gamma-tubulin is transcribed in n. crassa. in a phylogenetic tree that includes all known gamma-tubu ...19979358070
high-affinity no(3-)-h+ cotransport in the fungus neurospora: induction and control by ph and membrane voltage.high-affinity nitrate transport was examined in intact hyphae of neurospora crassa using electrophysiological recordings to characterize the response of the plasma membrane to no3- challenge and to quantify transport activity. the no3(-)-associated membrane current was determined using a three electrode voltage clamp to bring membrane voltage under experimental control and to compensate for current dissipation along the longitudinal cell axis. nitrate transport was evident in hyphae transferred ...19979351892
evidence for a cysteine-histidine thioether bridge in functional units of molluscan haemocyanins and location of the disulfide bridges in functional units d and g of the betac-haemocyanin of helix functional units d and g from the betac-haemocyanin of the gastropod helix pomatia, aminoacid analysis in the presence of dimethyl sulfoxide showed the occurrence of seven cysteine residues. titration with 5,5'-dithiobis(2-nitrobenzoic acid), however, did not reveal any free thiol group. pepsinolysis at ph 2.0 followed by amino acid analysis and partial sequencing of the cysteine-containing peptides showed that six cysteine residues are involved in the formation of three disulfide bridges at ...19979342242
dna methylation inhibits elongation but not initiation of transcription in neurospora plants, animals, and fungi, dna methylation is frequently associated with gene silencing, yet little is known about the role of the methylation in silencing. in neurospora crassa, repeated sequences are silenced by repeat-induced point mutation (rip) and genes that have suffered numerous gc --> at mutations by rip are typically methylated at remaining cytosines. we investigated possible effects on transcription from methylation associated with rip by taking advantage of 5-azacytidine, which p ...19979308966
temperature compensation of the circadian period length--a special case among general homeostatic mechanisms of gene expression?in neurospora crassa, as well as in other organisms, the expression of housekeeping genes is transiently suppressed after exposure to higher temperatures (30-45 degrees c); expression is then reactivated and adapts after a few-hours to values closer to the initial rates. adaptive mechanisms apparently exist in the processes of transcription, rna processing, and translation and render protein synthesis rates temperature compensated. heat shock proteins (hsps) play an important role within these m ...19979298284
temperature compensation and membrane composition in neurospora crassa.the link between temperature compensation of the circadian rhythm and temperature-induced adjustment of membrane composition in neurospora crassa is briefly reviewed. in common with most organisms, neurospora responds to changes in growth temperature by adjusting its lipid composition, primarily by increasing the degree of unsaturation of its fatty acids at low temperature. this may result in maintenance of either membrane fluidity or phase transition behavior over a range of temperatures. in ne ...19979298281
isolation of quelling-defective (qde) mutants impaired in posttranscriptional transgene-induced gene silencing in neurospora crassa.we report the isolation of 15 neurospora crassa mutants defective in "quelling" or transgene-induced gene silencing. these quelling-defective mutants (qde) belonging to three complementation groups have provided insights into the mechanism of posttranscriptional gene silencing in n. crassa. the recessive nature of the qde mutations indicates that the encoded gene products act in trans. we show that when qde genes are mutated in a transgenic-induced silenced strain containing many copies of the t ...19979294193
overlapping functions for two g protein alpha subunits in neurospora crassa.heterotrimeric g proteins, consisting of alpha, beta and gamma subunits, mediate a variety of signaling pathways in eukaryotes. we have previously identified two genes, gna-1 and gna-2, that encode g protein alpha subunits in the filamentous fungus neurospora crassa. mutation of gna-1 results in female infertility and sensitivity to hyperosmotic media. in this study, we investigate the expression and functions of gna-2. results from western analysis and measurements of gna-2 promoter-lacz fusion ...19979286674
ribosome stalling is responsible for arginine-specific translational attenuation in neurospora crassa.the neurospora crassa arg-2 upstream open reading frame (uorf) plays a role in negative arginine-specific translational regulation. primer extension inhibition analyses of arg-2 uorf-containing rna translated in a cell-free system in which arginine-specific regulation was retained revealed "toeprints" corresponding to ribosomes positioned at the uorf initiation and termination codons and at the downstream initiation codon. at high arginine concentrations, the toeprint signal corresponding to rib ...19979271370
heat shock protein 80 of neurospora crassa, a cytosolic molecular chaperone of the eukaryotic stress 90 family, interacts directly with heat shock protein 70.the subunit structure of hsp80, the most abundant heat-shock protein of neurospora crassa, was examined by chemical cross-linking of the purified protein in vitro. resolution of glutaraldehyde-treated hsp80 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis sds-page suggests that the native state of this protein is a tetramer; the relative proportion of cross-linked species, estimated by the fraction of protein recovered in each category, is consistent with a dimer-of-dimer structure. ...19979254620
allelic specificity at the het-c heterokaryon incompatibility locus of neurospora crassa is determined by a highly variable filamentous fungi, the ability to form a productive heterokaryon with a genetically dissimilar individual is controlled by specific loci termed het loci. only strains homozygous for all het loci can establish a heterokaryon. in neurospora crassa, 11 loci, including the mating-type locus, regulate the capacity to form heterokaryons. an allele of the het-c locus (het-cor) of n. crassa has been previously characterized and encodes a nonessential 966 amino acid glycine-rich protein. herein, we de ...19979258675
ppt-1, a neurospora crassa ppt/pp5 subfamily serine/threonine protein phosphatase.we isolated a n. crassa cdna clone encoding a novel-type serine/threonine phosphatase. the gene (mapped to lgvr), designated ppt-1, encodes a 479 amino acid putative polypeptide which contains a conserved tetratricopeptide repeat (tpr) motif. ppt-1 transcript levels are abundant in conidia and decrease during germination, indicating that ppt-1 is developmentally regulated.19979256060
novel pattern of dna methylation in neurospora crassa transgenic for the foreign gene has previously been reported that multiple copies of the hph gene integrated into the genome of neurospora crassa are methylated at hpa ii sites (ccgg) during the vegetative life cycle of the fungus, while hph genes integrated as single copies are not methylated. furthermore, methylation is correlated with silencing of the gene. we report here the methylation state of cytosine residues of the major part of the promoter region of the hph gene integrated into the genome of the multiple copy str ...19979171093
mutations of pma-1, the gene encoding the plasma membrane h+-atpase of neurospora crassa, suppress inhibition of growth by concanamycin a, a specific inhibitor of vacuolar atpases.concanamycin a (cca), a specific inhibitor of vacuolar atpases, inhibited growth of neurospora crassa in medium adjusted to ph 7 or above. mutant strains were selected for growth on medium containing 1.0 microm cca. sixty-four (of 66) mutations mapped in the region of the pma1 locus, which encodes the plasma membrane h+-atpase. analysis of v-atpase activity in isolated vacuolar membranes from the mutant strains showed wild-type activity and sensitivity to cca. in contrast, plasma membrane h+-atp ...19979169444
kinesin is essential for cell morphogenesis and polarized secretion in neurospora crassa.kinesin is a force-generating molecule that is thought to translocate organelles along microtubules, but its precise cellular function is still unclear. to determine the role of kinesin in vivo, we have generated a kinesin-deficient strain in the simple cell system neurospora crassa. null cells exhibit severe alterations in cell morphogenesis, notably hyphal extension, morphology and branching. surprisingly, the movement of organelles visualized by video microscopy is hardly affected, but apical ...19979214620
expressed sequences from conidial, mycelial, and sexual stages of neurospora the neurospora genome project at the university of new mexico, expressed sequence tags (ests) corresponding to three stages of the life cycle of the filamentous fungus neurospora crassa are being analyzed. the results of a pilot project to identify expressed genes and determine their patterns of expression are presented. 1,865 partial complementary dna (cdna) sequences for 1,409 clones were determined using single-pass sequencing. contig analysis allowed the identification of 838 unique ests ...19979290248
genome analysis on linkage group vi of neurospora crassa.two chromosome walks covering 420 and 110 kb on the left arm of linkage group vi (lgvil) of neurospora crassa were purscrooued with the goal of cloning carotenogenic loci. complementation analysis with clones isolated in the 420-kb walk allowed identification of the yellow-1 (ylo-1) gene which is essential for neurospora carotenogenesis. we have physically located a second gene, unknown-13 (un-13), between the cross-pathway control-1, (cpc-1) and ylo-1 loci. cloning of a second potential caroten ...19979290246
genome analysis in neurospora crassa; cloning of four loci arginine-1 (arg-1), methionine-6 (met-6), unknown-7 (un-7), and ribosome production-1 (rip-1) and associated chromosome walking.we have cloned four neurospora crassa genes by complementation analysis. cloned genes include the arginine-1 (arg-1), methionine-6 (met-6), unknown-7 (un-7), and ribosome production-1 (rip-1) loci. chromosome walks were initiated in ordered cosmid libraries from the cloned loci. a total of about 700 kb of the neurospora genome is covered in these walks.19979290245
mapping chromosome landmarks in the centromere i region of neurospora crassa.chromosome translocation breakpoints, rflp heterozygosity in partial chromosome duplications, and rflp-marked crossover events have been used as chromosomal landmarks to find the position and orientation of cloned regions flanking centromere i of neurospora crassa. determination of physical:genetic ratios in genomic regions flanking the loci mei-3, un-2, and his-2 supports previous evidence indicating that recombinational activity is lower in regions flanking centromere i than in the general n. ...19979290244
the genome and genes of neurospora crassa.neurospora crassa is an organism with a 7-decade contribution to genetic research. in a genome of 42.9 mb and just over 1000 map units, to date over 800 different genes have been identified by phenotype and/or map location, and 222 genes have been characterized by sequencing. methods by which analysis of the genome has been carried out are discussed, including linkage, rflp, and chromosome walking. characterized centomeres, telomeres, the nucleolar organizer and the dispersed 5s rrna genes are d ...19979290240
conformation and microenvironment of the active site of xylose reductase inferred by fluorescent chemoaffinity labeling.conformation and microenvironment at the active site of xylose reductase (xr) from neurospora crassa was probed with fluorescent chemoaffinity labeling (fcal) using o-phthalaldehyde as a chemical initiator. formation of a single isoindole derivative resulted in complete inactivation of the enzyme as judged by spectroscopic and fluorescence studies. kinetic analysis of the 2,4,6-trinitrobenzenesulfonic-acid-modified xr implicated the presence of an essential lysine residue at the active site of x ...19979208923
a neurospora crassa mutant altered in the regulation of l-amino acid oxidase.the isolation and characterization of a neurospora crassa mutant altered in l-amino oxidase regulation is reported. the previously isolated gln-1br8 strain, which only synthesizes the glutamine synthetase alpha monomer and lacks the beta monomer, was used as parental strain. a mutant derivative of strain was selected for its ability to grow on minimal medium in the presence of dl-methionine-sr-sulfoximine (mso), an inhibitor of glutamine synthetase activity. this gln-1br8;msor mutant overcame th ...19979202472
isolation and characterization of a temperature-sensitive circadian clock mutant of neurospora crassa.a new circadian clock mutant has been isolated in neurospora crassa. this new mutation, called period-6 (prd-6), has two features novel to known clock mutations. first, the mutation is temperature sensitive. at restrictive temperatures (above 21 degrees) the mutation shortens circadian period length from a wild-type value of 21.5 hr to 18 hr. at permissive temperatures (below 21 degrees) the mutant has a 20.5-hr period length close to that of the wild-type strain. second, the prd-6 mutation is e ...19979178003
cytosine methylation associated with repeat-induced point mutation causes epigenetic gene silencing in neurospora crassa.repeated dna sequences are frequently mutated during the sexual cycle in neurospora crassa by a process named repeat-induced point mutation (rip). rip is often associated with methylation of cytosine residues in and around the mutated sequences. here we demonstrate that this methylation can silence a gene located in nearby, unique sequences. a large proportion of strains that had undergone rip of a linked duplication flanking a single-copy transgene, hph (hygromycin b phosphotransferase), showed ...19979178002
bioelectrorheological model of the cell. 7. cellular deformation in the presence of cytochalasin b.the influence of cytochalasin b on the mechanical properties of neurospora crassa cells subjected to a periodic electric field was investigated. shear and extensional deformations were considered and studied separately. conditions were found under which shear deformations become irreversible. rheological models helped in the interpretation of the results in terms of the different response to the shear stress of the three hypothetical supramolecular regions of the membrane-skeleton network (f, s ...20139474262
pronounced cytoplasmic ph gradients are not required for tip growth in plant and fungal cells.the existence of pronounced cytoplasmic ph gradients within the apices of tip-growing cells, and the role of cytoplasmic ph in regulating tip growth, were investigated in three different cell types: vegetative hyphae of neurospora crassa; pollen tubes of agapanthus umbellatus; and rhizoids of dryopteris affinis gametophytes. examination of cytoplasmic ph in growing cells was performed by simultaneous, dual emission confocal ratio imaging of the ph-sensitive probe carboxy snarf-1. considerable at ...19979191043
a putative role for calmodulin in the activation of neurospora crassa chitin synthase.the possible role of calmodulin in cell wall formation and chitin synthesis was studied in neurospora crassa by examining the effects of anti-calmodulin agents on protoplast regeneration and possible associations between chitin synthase and calmodulin related proteins in microsomal isolates. protoplast regeneration was inhibited by trifluoperazine (> 20 microm), an anticalmodulin agent. chitin synthase activity in microsomes was associated with that of calmodulin-dependent protein kinase and inh ...19979163912
mutation of the cys-9 gene, which encodes thioredoxin reductase, affects the circadian conidiation rhythm in neurospora crassa.ten cysteine auxotrophs of neurospora crassa were examined with regard to the period lengths of their circadian conidiation rhythms. one of the these cysteine auxotrophs, cys-9, showed dramatic changes in the circadian conidiation rhythm. at 10 microm methionine, the cys-9 mutant had a period length that was 5 hr shorter than that of the wild-type strain during the first 3 days after transfer to continuous darkness. at this concentration of methionine, the period length was unstable after the fo ...19979136004
inhibition of neurospora crassa growth by a glucan synthase-1 antisense construct.we have used the filamentous fungus, neurospora crassa, as a model system to test the concept that antisense targeting of the cell-wall assembly enzyme, (1,3)beta-glucan synthase [e.c.; udpglucose: 1,3-beta-d-glucan 3-beta-d-glucosyltransferase], leads to a corresponding decrease in growth of the organism. previously, our laboratory isolated a gene (glucan synthase-1, gs-1) that is required for (1,3)beta-glucan synthase activity. wild-type cells were transformed with dna vectors encodin ...19979099631
a ras homologue of neurospora crassa regulates order to study the role of signal transduction pathways in the regulation of morphology in neurospora crassa, we cloned and characterized a ras homologue, termed nc-ras2. the predicted protein product of this gene is composed of 229 amino acid residues and contains all the consensus sequences shared by the ras protein family. the gene is located in linkage group v. an nc-ras2 disruptant showed morphological characteristics very similar to those of the smco7 mutant, which also maps to linkage ...19979180696
a gene required for nuclear migration in neurospora crassa codes for a protein with cysteine-rich, lim/ring-like domains.the ro mutants of neurospora crassa are defective in nuclear migration and hyphal morphogenesis. several of the ro loci have recently been shown to encode components of the dynein/dynactin motor complex. here we report on the cloning and characterization of the ro-2 gene which codes for a novel 80 kda protein that has two cys-rich motifs which resemble zinc-binding lim or ring domains thought to mediate protein-protein interactions. ro2 also contains several potential binding sites for src homol ...19979159520
identification of genes induced in alkaloid-producing cultures of claviceps order to identify genes which are expressed during alkaloid synthesis in an axenic culture of claviceps sp. (strain atcc 26245), a cdna library from a producing culture was differentially screened with cdna from producing (cdna+) and non-producing (cdna-) cultures, respectively. altogether, ten cdna clones were obtained, the alkaloid-synthesis-correlated expression of which was confirmed by northern analyses. evaluation of their nucleotide and derived amino-acid sequences identified one gene ...19979108144
mutants of neurospora crassa defective in regulation of blue light perception.a new selection system was used to isolate mutants deficient in regulation of blue light perception in neurospora crassa. this selection system has two possible applications and was used for the isolation of either blind or constitutive mutants. we isolated 17 uv-induced mutants that showed the pleiotropic white collar (wc) phenotype and were completely blocked in transduction of the light signal. from the segregation pattern in sexual crosses, we tentatively assigned the 17 mutants to either th ...19979108272
mutagenic activity and specificity of hydrogen peroxide in the ad-3 forward-mutation test in two-component heterokaryons of neurospora the ad-3 forward-mutation test, hydrogen peroxide was at best a weak mutagen in nongrowing conidia from a dna repair-proficient heterokaryon (h-12, uvs-2+/uvs-2+) but was a moderate mutagen in nongrowing conidia from a dna-repair-deficient heterokaryon (h-59, uvs-2/uvs-2) over a narrow range of high concentrations. h-59 also was more sensitive than h-12 to the killing activity of hydrogen peroxide at high concentrations. thus, a dna-repair pathway, of which the gene product of the uvs-2+ alle ...19979100841
purification of a 47-kda calmodulin-binding polypeptide as an actin-binding protein from neurospora crassa.we have enriched a 47-kda polypeptide (p47) from neurospora crassa on the basis of its affinity to calmodulin. the p47 was purified to homogeneity by chromatography on a mono s cation exchange column and evidence is presented that the polypeptide co-sediments specifically with f-actin. the intracellular distribution of p47 and actin was also examined using indirect double immunofluorescence staining of cells at different stages of development. our results suggest that by altering the conformatio ...19979119196
melanogenesis, tyrosinase expression, and reproductive differentiation in black and white truffles (ascomycotina).white and black truffles of the genus tuber are ascomycotina as well as neurospora crassa, which expresses tyrosinase dependently on the reproductive cycle. tyrosinase expression dependent on reproductive differentiation has been also described in black truffles. we present novel and comparative work on melanogenic activities in black and white truffles that both express true tyrosinases. l-tyrosine 3-monooxygenase and l-dopa oxidase activities colocalize as histochemically detected and are simi ...20169170162
[energy and metabolic intercellular interaction in the growth region of neurospora crassa]. 19979147633
developmental and photoregulation of three neurospora crassa carotenogenic genes during conidiation induced by desiccationneurospora crassa asexual sporulation (conidiation) is induced by different cues including desiccating aerial environments. three of the genes that are expressed during this developmental pathway are the albino (al) genes, which encode carotenoid biosynthetic enzymes. if conidiation is induced by nutrient deprivation in liquid culture, two overlapping al-3 mrnas, al-3 (m) and al-3 (c), are expressed (arpaia et al., 1995, dev. biol. 170, 620-635). here we quantitate accumulation of each of the fo ...19979073484
characterization of neurospora mitochondrial group i introns reveals different cyt-18 dependent and independent splicing strategies and an alternative 3' splice site for an intron orf.the neurospora crassa mitochondrial tyrosyl-trna synthetase (cyt-18 protein) functions in splicing the n. crassa mitochondrial large rrna intron by stabilizing the catalytically active structure of the intron core. here, a comprehensive study of n. crassa mtdna group i introns identified two additional introns, cob-i2 and the nd1 intron, that are dependent on cyt-18 for splicing in vitro and in vivo. the other seven n. crassa mtdna group i introns are not cyt-18-dependent and include five that s ...19979042940
arginine-specific regulation mediated by the neurospora crassa arg-2 upstream open reading frame in a homologous, cell-free in vitro translation system.translational control mediated by an upstream open reading frame (uorf) in the 5'-leader of the neurospora crassa arg-2 mrna was reconstituted in a homologous, cell-free in vitro translation system. a cell-free n. crassa system was developed that required the presence of cap and poly(a) on rna for maximal translation and that was amino acid-dependent. the 24-codon arg-2 uorf, when placed in the 5'-leader region of capped and adenylated synthetic luciferase rnas, conferred arg-specific negative r ...19978995256
white collar 2, a partner in blue-light signal transduction, controlling expression of light-regulated genes in neurospora crassa.a saturating genetic dissection of 'blind' mutants in neurospora crassa has identified a total of two non-redundant loci (wc-1 and wc-2) each of which is required for blue-light perception/signal transduction. previously, we demonstrated that wc1 is a putative zinc finger transcription factor able to bind specifically to a light-regulated promoter. here, we present the cloning and characterization of the wc-2 gene. we demonstrate using mutation analysis and in vitro dna-binding assays that wc2, ...19979009271
analysis of electrical phenomena accompanying the growth of neurospora crassa hyphae: theory and describe electrical phenomena observed in growth of neurospora crassa hyphae, a theoretical model was developed considering the hypha as a one-dimensional electric cable with non-uniform longitudinal distribution of current sources reflecting the activity of proton pumps. a profile of the density of the pump current along the hypha is proposed, at which the results of simulation quantitatively coincide with the results of physiological experiments. the model values of energy coupling in the g ...19979460054
hydrophobic properties of nad glycohydrolase from neurospora crassa conidia and interaction with dioxane.nad glycohydrolase (nadase, ec from neurospora crassa conidia shows marked hydrophobic properties which are related to the self inhibition of the enzyme. both aliphatic amines and carboxylic acids are able to inhibit noncompetitively the catalytic activity of the enzyme and the inhibition depends on the non-polar moiety of the substances. also dioxane is an inhibitor of nad glycohydrolase even though it apparently increases the specific activity of the enzyme. this effect can be explain ...19979193681
evidence for and characterization of cytochrome p-450 in neurospora crassa.cytochrome p-450 was detected in microsomes and presumably in cytosol of neurospora crassa, and was found to be inducible by progesterone. in the microsomal fraction cytochrome b5 and nadph-cytochrome c reductase activities were measurable, too. cytochrome p-450 of neurospora crassa is inhibited by skf-525 a and by inhibitors of ergosterol biosynthesis. after induction of cytochrome p-450 with progesterone 11 alpha-hydroxyprogesterone as one metabolite of progesterone was detected in the culture ...19979151426
transport of small lons and molecules through the plasma membrane of filamentous fungi.less than 1% of the estimated number of fungal species have been investigated concerning the transport of low-molecular-weight nutrients and metabolites through the plasma membrane. this is surprising if one considers the importance of the processes at the plasma membrane for the cell: this membrane mediates between the cell and its environment. concentrating on filamentous fungi, in this review emphasis is placed on relating results from biophysical chemistry, membrane transport, fungal physiol ...19979097013
pathways for fatty acid elongation and desaturation in neurospora crassa.neurospora crassa incorporated exogenous deuterated palmitate (16:0) and 14c-labeled oleate (18:1 delta 9) into cell lipids. of the exogenous 18:1 delta 9 incorporated, 59% was desaturated to 18:2 delta 9,12 and 18:3 delta 9,12,15. of the exogenous 16:0 incorporated, 20% was elongated to 18:0, while 37% was elongated and desaturated into 18:1 delta 9, 18:2 delta 9,12, and 18:3 delta 9,12,15. the mass of unsaturated fatty acids in phospholipid and triacylglycerol is 12 times greater than the mass ...19979075186
a tyrosyl-trna synthetase recognizes a conserved trna-like structural motif in the group i intron catalytic core.the neurospora crassa mitochondrial (mt) tyrosyl-trna synthetase (cyt-18 protein) functions in splicing group i introns, in addition to aminoacylating trna(tyr). here, we compared the cyt-18 binding sites in the n. crassa mt lsu and nd1 introns with that in n. crassa mt trna(tyr) by constructing three-dimensional models based on chemical modification and rna footprinting data. remarkably, superimposition of the cyt-18 binding sites in the model structures revealed an extended three-dimensional o ...19968978617
a dominant negative effect of eth-1r, a mutant allele of the neurospora crassa s-adenosylmethionine synthetase-encoding gene conferring resistance to the methionine toxic analogue ethionine.eth-1r, a thermosensitive allele of the neurospora crassa s-adenosylmethionine (adomet) synthetase gene that confers ethionine resistance, has been cloned and sequenced. replacement of an aspartic amino acid residue (d48-->n48), perfectly conserved in prokaryotic, fungal and higher eukaryotic adomet synthetases, was found responsible for both thermosensitivity and ethionine resistance conferred by eth-1r. gene fusion constructs, designed to overexpress eth-1r in vivo, render transformant cells r ...19968978034
role of cytosolic serine hydroxymethyltransferase in one-carbon metabolism in neurospora crassa.conidiospores of wild type and two mutant strains of neurospora crassa were grown on [3-13c]serine, [2-13c]glycine, or [13c]formate. acid extracts of the mycelia were analyzed by 13c nmr for incorporation of the 13c label into choline, serine, and adenine. the goal was to elucidate the function of cytosolic serine hydroxymethyltransferase by comparison of a mutant strain lacking this activity and requiring formate for optimal growth (for mutant strain) to the wild-type strain and the ser3 strain ...19968914930
circadian clock-controlled genes isolated from neurospora crassa are late night- to early endogenous circadian biological clock controls the temporal aspects of life in most organisms, including rhythmic control of genes involved in clock output pathways. in the fungus neurospora crassa, one pathway known to be under control of the clock is asexual spore (conidia) development. to understand more fully the processes that are regulated by the n. crassa circadian clock, systematic screens were carried out for genes that oscillate at the transcriptional level. time-of-day-specific cdn ...19968917550
metabolism of ricinoleate by neurospora crassa.neurospora crassa is a potential expression system for evaluating fatty-acid-modifying genes from plants producing uncommon fatty acids. one such gene encodes the hydroxylase that converts oleate to ricinoleate, a fatty acid with important industrial uses. to develop this expression system, it is critical to evaluate the metabolism and physiological effects of the expected novel fatty acid(s). we therefore examined effects of ricinoleate on lipid biosynthesis and growth of n. crassa. ricinoleate ...19968987727
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