PMID(sorted descending)
regulation of synthesis of ribosomal protein in neurospora crassa. 19826217082
l-myoinositol-1-phosphate synthase from neurospora crassa: purification to homogeneity and partial characterization. 19826216853
characterization of mms-sensitive mutants of neurospora crassa.several mms-sensitive mutants of neurospora crassa were compared with the wild-type strain for their relative sensitivities to uv, x-ray, and histidine. they were also compared for the frequency of spontaneous mutation at the loci which confer assistance to p-fluorophenylalanine. the mutants were also examined for possible defects in meiotic behavior in homozygous crosses and for any change in the inducible dna salvage pathways (as indicated by their ability to utilize dna as the sole phosphate ...19826216404
[influence of light on membrane potential of neurospora crassa cells].in experiments with left atrial and right ventricular tissues fast sodium current (ina) was decreased by substituting sucrose for sodium in tyrode's solution and with antiarrhythmic drugs--ina blockers (lidocaine, diphenylhydantoine and ethmozine). it was shown that ina decrease results in the growth of refractoriness (r) of the cardiac tissues. the hypothesis is advanced that the r growth caused by ina decrease is one of the mechanisms of selective sensitiveness of ischemic heart tissues to ant ...20066215949
nitrogen-15 spin-lattice relaxation times of amino acids in neurospora crassa as a probe of intracellular environment.the nitrogen-15 spin-lattice relaxation time, t1, and the nuclear overhauser enhancement (noe) have been measured for intracellular glutamine, alanine, and arginine in intact neurospora crassa mycelia to probe their various intracellular environments. the relaxations of 15n gamma of glutamine, 15n alpha of alanine, and 15n omega, omega ' of arginine in n. crassa were found, on the basis of their noe values, to be predominantly the result of 15n-h dipolar relaxation. these relaxations are therefo ...19826215941
circadian rhythms in neurospora crassa: oscillations in fatty acids. 19826215940
structure of the outer mitochondrial membrane: ordered arrays of porelike subunits in outer-membrane fractions from neurospora crassa mitochondria.light-membrane fractions obtained by hypoosmotic lysis of neurospora crassa mitochondria exhibit buoyant densities and marker-enzyme activities characteristic of outer mitochondrial membranes. sds page of these membrane fractions indicates that a polypeptide of m(r) 31,000 is the main protein component. under negative-stain electron microscope examination many of the membranes in these fractions appear as large (0.5-1- mum diameter), collapsed vesicles. the surfaces of flattened, open (i.e., rip ...19826215413
an immunological study of the interaction of ligands with pyruvate kinase of neurospora crassa.antibodies against pyruvate kinase of neurospora crassa, induced in rabbits, were used to monitor the interaction of ligands with this enzyme. the technique of microcomplement fixation was employed to probe for conformational alterations elicited by binding of substrates (phosphoenolpyruvate (pep) and adenosine diphosphate), the allosteric activator (fructose 1,6-diphosphate), and the inhibitor (valine). on binding of pep and valine to pyruvate kinase a pronounced reduction in the extent of comp ...19826215112
separation of neurospora crassa myo-inositol-1-phosphate synthase from glucose-6-phosphate dehydrogenase by affinity chromatography.the purification of neurospora crassa myo-inositol-1-phosphate synthase (ec was studied by affinity chromatography using the substrate (glucose-6-phosphate), the inhibitor (pyrophosphate), the coenzyme (nad+) and the coenzyme analogues (5'amp and cibacron blue f3g-a) of the enzyme as adsorbents attached to agarose gel. myo-inositol-1-phosphate synthase could be separated completely from the contaminating substance, glucose-6-phosphate dehydrogenase (ec, on blue sepharose cl-6b ...19826214775
cross-pathway control of ornithine carbamoyltransferase synthesis in neurospora crassa.the pattern of cross-pathway regulation of the arginine synthetic enzyme ornithine carbamoyltransferase was investigated in neurospora crassa, using single and double mutant auxotrophic strains starved for their required amino acids. these experiments show that starvation for histidine, tryptophan, isoleucine, valine or arginine can result in derepression of ornithine carbamoyltransferase. methionine starvation also gave slight derepression, but starvation for lysine or leucine gave little or no ...19826214612
inhibition of the plasma membrane [h+]-atpase of neurospora crassa by n-ethylmaleimide. protection by nucleotides.pre-incubation of the plasma membrane [h+]-atpase of neurospora crassa with the sulfhydryl reagent, n-ethylmaleimide (nem), leads to a marked inhibition of atpase activity. loss of activity depends upon preincubation ph and follows pseudo-first order kinetics with respect to nem concentration. mgatp, the physiological substrate for atpase activity, protects against nem inactivation with an average dissociation constant of 1.5 mm at 0 degrees c. this value agrees well with the measured km for mga ...19826214555
physiological adaptation to the loss of amino acid transport ability.a strain of neurospora crassa devoid of constitutive amino acid transport ability can utilize arginine as the sole nitrogen source. nitrogen starvation, presence of arginine, and mutational inactivation of the general permease are key factors in signaling production of an extracellular enzyme which removes the alpha-amino group from the amino acid.19826214547
polyamine-deficient neurospora crassa mutants and synthesis of cadaverine.the polyamine path of neurospora crassa originates with the decarboxylation of ornithine to form putrescine (1,4-diaminobutane). putrescine acquires one or two aminopropyl groups to form spermidine or spermine, respectively. we isolated an ornithine decarboxylase-deficient mutant and showed the mutation to be allelic with two previously isolated polyamine-requiring mutants. we here name the locus spe-1. the three spe-1 mutants form little or no polyamines and grow well on medium supplemented wit ...19826214545
characterization of neurospora crassa catabolic dehydroquinase purified from n. crassa and escherichia coli.1. neurospora crassa catabolic dehydroquinase has been purified from n. crassa and escherichia coli. 2. protein-sequence and gel-electrophoretic data show that apparently pure, homogeneous native dehydroquinase is a mixture of intact and proteinase-cleaved enzyme monomers. 3. protein-sequence data and steady-state kinetics show that the catabolic dehydroquinase gene of n. crassa is expressed with fidelity in e. coli.19826214255
comparison of the induction of specific locus mutations in wild-type and repair-deficient strains of neurospora crassa.a comparison of mutation induction between wild-type and excision repair-deficient strains has shown that, after treatment with four of the five mutagens tested, an enhanced recovery of induced mutants was found in the excision repair-deficient strains. in this sense we have confirmed for neurospora ames' (1977) observations with salmonella. furthermore, genetic analysis of the mutants induced in neurospora in both wild-type and excision repair-deficient strains has shown that in some cases the ...19826214249
nitrogen metabolite repression of fluoropyrimidine resistance and pyrimidine uptake in neurospora crassa.wild type neurospora crassa was shown to be more resistant to 5-fluoro-uracil, 5-fluoro-uridine and 5-fluoro-2'-deoxyuridine in the presence of ammonia than in its absence. this differential resistance may in part be accounted for by the observation that both uracil and uridine uptake in germinating conidia is under nitrogen metabolite regulation. the uptake of uracil and uridine is increased on poor nitrogen sources in wild type, is unaffected by nitrogen source in a nit-2 mutant strain while a ...19826213838
the role of pyrimidine dimers in postreplication repair in neurospora.using the micrococcus luteus dimer specific endonuclease assay of wilkins (1973), and photoreactivation we have examined the induction and fate of ultraviolet induced pyrimidine dimers in the excision defective strain, uvs-2, of neurospora crassa. dimer induction was fluence dependent from 0 to 800 ergs/mm2 uv. an interdimer distance of 19.6 x 10(6) dna molecular weight was found after a fluence of 220 ergs/mm2. we confirm the earlier report that this mutant is completely excision defective (wor ...19826213836
calmodulin from neurospora crassa. general properties and conformational changes.calmodulin from neurospora crassa has been purified to electrophoretic homogeneity. equilibrium gel filtration experiments suggest that its ca-binding properties are indistinguishable from those of vertebrate calmodulins. the isoelectric point of 4.04 and electrophoretic behavior under nondenaturing conditions indicate that n. crassa calmodulin is slightly less acidic than its vertebrate counterpart. the amino acid composition is typical of plant calmodulins with the exception that trimethyllysi ...19826213623
identification and properties of an atpase in vacuolar membranes of neurospora crassa.using a vacuolar preparation virtually free of contamination by other organelles, we isolated vacuolar membranes and demonstrated that they contain an atpase. sucrose density gradient profiles of vacuolar membranes show a single peak of atpase activity at a density of 1.11 g/cm3. comparison of this enzyme with the two well-studied proton-pumping atpases of neurospora plasma membranes and mitochondria shows that it is clearly distinct. the vacuolar membrane atpase is insensitive to the inhibitors ...19826213602
radioautographic detection of macromolecules involved in the synthesis of neurospora crassa cell wall. 19826213305
regulation of ribosomal rna cistron number in a strain of neurospora crassa with a duplication of the nucleolus organizer region.some progeny from a cross of the translocation mutant t(vl leads to ivl)ar33 with wild-type neurospora crassa are double nucleolus organizer (dno) strains, usually displaying two distinct nucleolus organizer regions. the dno strain is sterile but displays the same growth response as normal laboratory strains of neurospora. we used dna-dna hybridization techniques to quantify the number of rrna cistrons in the dno mutant and its vegetative progeny. comparisons of the rate of hybridization of geno ...19826213268
the functional unit of the arom conjugate in neurospora.the functional unit of arom polyenzyme conjugate of neurospora crassa was determined by analysis of radiation inactivation of each of the five activities in the conjugate. the functional targets for all five enzymes were in close agreement with the value of 300,000 obtained by conventional hydrodynamic procedure for the native dimeric structure. these data indicate that at least 95% of the functional enzyme system in crude extracts exists in a dimeric form and that both polypeptide chains of the ...19826212584
biosynthesis of glyoxysomal enzymes in neurospora crassa. 19826212015
two types of microbodies in neurospora crassa. 19826212014
a simplified method for the simultaneous detection of intragenic and intergenic mutations (deletions) in neurospora crassa. 19826211615
postreplication repair in neurospora crassa.changes in the molecular weight of nascent dna made after ultraviolet (uv) irradiation have been studied in the excision-defective neurospora mutant uvs-2 using isotopic pulse labeling, alkaline gradient centrifugation and alkaline filter elution. both the size of nascent dna and the rate of incorporation of label into dna was reduced by uv light in a dose dependent manner. however, this dna repair mutant did recover the ability to synthesize control-like high molecular weight dna 3 hours after ...19826211589
relationship between the composition of phospholipids and respiratory activity of choline-deficient mutants of neurospora crassa.phosphatidylcholine is one of the most frequent phospholipid components of the inner mitochondrial membrane of neurospora crassa. quantitative analysis of phosphlipids of the wild strain of neurospora crassa and of its two cho mutants showed that these strains did not significantly differ in the content of phosphatidylcholine. mutants cultivated in a medium without choline contained, as compared with the wild strain, an increased amount of phosphatidylserine and a decreased quantity of phosphati ...19826211400
mutants affecting amino acid cross-pathway control in neurospora crassa. 19826211391
5'-untranslated sequences of two structural genes in the qa gene cluster of neurospora crassa.the coding regions of two genes (qa-2 and qa-3) in the qa gene cluster of neurospora crassa have been localized by nucleotide sequence analysis combined with data on previously determined nh2-terminal amino acid sequences for the proteins that these genes encode. the start point of transcription for each of these genes has been determined by nuclease s1 mapping experiments with poly(a)+rna isolated from quinic acid-induced cultures of n. crassa. the sequences of approximately 200 nucleotides 5' ...19826210913
[photoinduction of carotenoid synthesis by neurospora crassa on different structural and functional states of nitrate reductase].in order to clarify the role of nitrate reductase as a potential photoreceptor, the ability of n. crassa mycelial cells for light-dependent accumulation of carotenoid pigments has been studied. the repression of the nitrate reductase synthesis by ammonium ions has been found not to influence the rate of the photoinduced carotenogenesis. the mutant experiments have shown that damage to the structural integrity of the nitrate reductase molecule, e, g., disintegrated synthesis of the protein fragme ...20066210905
comparison of amino acid sequence and thermostability of tyrosinase from three wild type strains of neurospora crassa.the thermostability of tyrosinase from three wild type strains of neurospora crassa has been investigated. for this purpose a sequence comparison of two thermostable and one thermolabile tyrosinase isoenzyme was carried out. it revealed that at position 201 the thermostable enzyme forms share an aspartate residue in contrast to an asparagine residue in the thermolabile form. in addition, one of the thermostable isoenzymes displays five other substitutions. since the relative stability of the the ...19826210697
primary structure of tyrosinase from neurospora crassa. ii. complete amino acid sequence and chemical structure of a tripeptide containing an unusual align the four cyanogen bromide peptides of neurospora tyrosinase whose amino acid sequences were reported in the preceding paper, suitable methionine-containing overlap peptides were isolated. the required peptides were obtained by tryptic, peptic, and thermolytic digestion of the unmodified protein and of the maleylated derivative. from the partial sequence information of these peptides and a cyanogen bromide overlap peptide, the four cyanogen bromide fragments were aligned in the order cb3 ...19826210696
primary structure of tyrosinase from neurospora crassa. i. purification and amino acid sequence of the cyanogen bromide fragments.cyanogen bromide (cb) cleavage of neurospora tyrosinase resulted in four major fragments, cb1 (222 residues), cb2 (82 residues), cb3 (68 residues), and cb4 (35 residues), and one minor overlap peptide cb2-4 (117 residues) due to incomplete cleavage of a methionylthreonyl bond. the sum of the amino acid residues of the four major fragments matches the total number of amino acid residues of the native protein. the amino acid sequences of the cyanogen bromide fragments cb2, cb3, and cb4 were determ ...19826210695
regulation of l-phenylalanine ammonia-lyase by l-phenylalanine and nitrogen in neurospora crassa.neurospora crassa possesses an inducible l-phenylalanine ammonia-lyase that is expressed only when cells are derepressed for nitrogen in the presence of l-phenylalanine. enzyme synthesis requires both induction by l-phenylalanine and simultaneous nitrogen catabolite derepression. carbon limitation in the presence of phenylalanine does not elicit induction of l-phenylalanine ammonia-lyase. specific induction by l-phenylalanine is required, and other amino acids completely failed to induce any lya ...19826210688
extracellular acid proteases from neurospora crassa.three electrophoretically distinct acid proteases appear in culture filtrates of neurospora crassa. like the previously investigated alkaline and neutral proteases, these enzymes require induction by an exogenous protein. but in contrast to alkaline and neutral proteases, which are synthesized and secreted in response to limitation of any one of three nutrilites (carbon, nitrogen or sulfur), extracellular elaboration of the acidic proteases is more specifically a function of the missing nutrilit ...19826210687
phosphate mediated regulation of some of the enzymes of carbohydrate metabolism in neurospora crassa. 19826210569
purification and characterisation of a pore protein of the outer mitochondrial membrane from neurospora crassa.the major protein of the outer mitochondrial membrane of neurospora was purified. on dodecylsulfate-containing gels it displayed a single band with an apparent molecular weight of 31 000. reconstitution experiments with artificial lipid bilayers showed that this protein forms pores. pore conductance was dependent on the voltage across the membrane. the protein inserted into the membrane in an oriented fashion, the membrane current being dependent on the sign of the voltage. single pore conductan ...19826210532
ultrastructural aspects of cytoplasmic ribosomes from histoplasma capsulatum and blastomyces dermatitidis as revealed by heavy metal staining.cytoplasmic ribosomes were isolated and purified from sonicates of the mycelial and yeastlike growth forms of the pathogenic dimorphic fungi, histoplasma capsulatum and blastomyces dermatitidis. similar ribosomal fractions were prepared from neurospora crassa and saccharomyces cerevisiae. these latter organisms were selected as typical filamentous and yeastlike monophasic fungi, and their ribosomes were used as reference standards. high resolution electron microscopy permitted a comparison of bo ...19846206396
preparative-scale isolation and purification of procaryotic and eucaryotic ribosomal 5 s rna: bacillus subtilis, neurospora crassa, and wheat germ.ribosomal 5 s rna from three different organisms has been isolated in high yield and purity. without prior isolation of ribosomes, a presoak in buffer followed by phenol extraction, de-32 ion-exchange chromatography, and sephadex g-75 gel-permeation chromatography yields at least 5-10 mg of electrophoretically homogeneous 5 s rna from 100 g of cells. ribonuclease activity is eliminated by various combinations of low temperature, sodium dodecyl sulfate, phenol, and bentonite. high-molecular-weigh ...19846204554
interactions between avian myeloblastosis reverse transcriptase and trnatrp. mapping of complexed trna with chemicals and nucleases.the interactions between beef trnatrp with avian myeloblastosis reverse transcriptase have been studied by statistical chemical modifications of phosphate (ethylnitrosourea) and cytidine (dimethyl sulfate) residues, as well as by digestion of complexed trna by cobra venom nuclease and neurospora crassa endonuclease. results with nucleases and chemicals show that reverse transcriptase interacts preferentially with the d arm, the anticodon stem and the t psi stem. all these regions are located in ...19846200830
molecular cloning of middle-abundant mrnas from neurospora crassa. 19836197613
purification and properties of a low molecular weight dna polymerase from neurospora crassa.a third dna polymerase 'c' with low molecular weight was isolated and purified 3700-fold from ground hyphae of neurospora crassa wt 74 a, which shows similarities to beta- and gamma-polymerases from higher eukaryotes: preference for poly(ra)(dt) as a template/primer, inhibition by p-chloromercuribenzoate, resistance against n-ethylmaleimide up to 10 mmol/l, and molecular weight of about 40000. this polymerase elutes as a distinct peak from deae-cellulose at 0.60 mol/l kcl and has an optimum for ...19836197088
folylpolyglutamate synthetase activities of neurospora crassa: nature of products formed by soluble and particulate enzymes in the wild type and polyglutamate-deficient mutants.the folylpolyglutamate synthetase activities of neurospora crassa wild type (fgsc 853) and two polyglutamate-deficient mutants (met-6, 35809, fgsc 1330 and mac, 65108, fgsc 3609) were examined using dialyzed extracts prepared during exponential mycelial growth. enzyme assay was based on incorporation of [u-3h]glutamate in folylpolyglutamates that were separated by gradient elution from deae-cellulose. extracts of the wild type produced h4pteglu2 (15%), h4pteglu3 (35%) and h4pteglu6 (50%) when an ...19836193684
mutagenesis at the ad-3a and ad-3b loci in haploid uv-sensitive strains of neurospora crassa. vi. genetic characterization of ad-3 mutants provides evidence for qualitative differences in the spectrum of genetic alterations between wild-type and nucleotide excision-repair-deficient strains.genetic characterization of ad-3b mutants induced in wild-type and uv-sensitive strains has revealed qualitative differences between the spectra of genetic alterations at the molecular level. ad-3b mutants induced in the two nucleotide excision-repair-deficient strains upr-1 and uvs-2 (worthy and epler, 1973) had significantly lower frequencies of nonpolarized complementation patterns and higher frequencies of noncomplementing mutants than ad-3b mutants induced in the wild-type strain in samples ...19836188039
mutation at the am locus of neurospora crassa.forty-eight new mutations at the am locus of neurospora crassa have been characterized. nineteen mutations were induced by uv; of these, eight were missense, two were frameshifts, two were nonsense, three were deletions and four were unidentified. twenty-nine mutations were induced with nitrous acid; of these, twenty-one were missense, three were frameshifts, one was nonsense, two were deletions and one was genetically unstable.20166177580
guanine uptake and metabolism in neurospora crassa.guanine is transported into germinated conidia of neurospora crassa by the general purine base transport system. guanine uptake is inhibited by adenine and hypoxanthine but not xanthine. guanine phosphoribosyltransferase (gprtase) activity was demonstrated in cell extracts of wild-type germinated conidia. the km for guanine ranged from 29 to 69 micro m in gprtase assays; the ki for hypoxanthine was between 50 and 75 micro m. the kinetics of guanine transport differ considerably from the kinetics ...19826174500
inhibition of rna synthesis in neurospora crassa hyphae treated with picolinic acid.picolinic acid, a metal-chelating agent, blocks the nuclei of germinating conidia of neurospora crassa in the g1 phase. the addition of picolinic acid to exponentially growing cultures of n. crassa in glucose medium causes an immediate inhibition of growth. concentrations higher than 50 mm completely inhibit growth of mycelia, whereas lower concentrations (20-30 mm) give only a partial inhibition. picolinic acid, added at the concentration of 20 mm, immediately blocks the accumulation of stable ...19816173217
different transport pathways of individual precursor proteins in mitochondria.transport of mitochondrial precursor proteins into mitochondria of neurospora crassa was studied in a cell-free reconstituted system. precursors were synthesized in a reticulocyte lysate programmed with neurospora mrna and transported into isolated mitochondria in the absence of protein synthesis. uptake of the following precursors was investigated: apocytochrome c, adp/atp carrier and subunit 9 of the oligomycin-sensitive atpase. addition of high concentrations of unlabelled chemically prepared ...19816167439
genetic analysis of ad-3 mutants induced by af-2 and two other nitrofurans in neurospora crassa.our previous studies have shown that the nitrofurans af-2, sq18506, and fanft are potent mutagens in neurospora crassa. the genetic damage produced by these chemicals at the ad-3 region in n crassa has been characterized by a series of genetic tests. the results of these tests indicate that all three agents induce a high frequency of point mutations and probably a low frequency of multilocus deletions. a comparison of the complementation patterns among the af-2--induced ad-3b mutants and those i ...19816165577
mutagenesis at the ad-3a and ad-3b loci in haploid uv-sensitive strains of neurospora crassa. iv. comparison of dose-response curves for mnng, 4nqo and icr-170 induced inactivation and mutation-induction.the genetic effects of mnng, 4nqo and icr-170 have been compared on 5 different uv-sensitive strains and a standard wild-type strain of neurospora crassa with regard to inactivation and the induction of forward-mutations at the ad-3a and ad-3b loci. whereas all uv-sensitive strains (upr-1, uvs-2, uvs-3, uvs-5 and uvs-6) are more sensitive to inactivation by mnng and icr-170 than wild-type, only uvs-5 shows survival comparable to wild-type after 4nqo treatment, all other strains are more sensitiv ...19816163076
rnase-sensitive dna polymerase activity in cell fractions and mutants of neurospora crassa.rnase-sensitive dna polymerase activity (rsdp) was tested in different cell fractions of neurospora crassa cell types and its morphological mutants. this rsdp was found localized in the microsomal pellet fraction and absent in the purified nuclear pellets isolated from different n. crassa cell types: conidia, germinated conidia, and mycelia. this enzyme is capable of synthesizing a dna product only in the presence of all four deoxyribonucleoside-5' - triphosphates and mg2+. removal of rna from t ...19806162450
purification and properties of neurospora crassa endo-exonuclease, an enzyme which can be converted to a single-strand specific endonuclease. 19806154864
sequence complexity and abundance classes of nuclear and polysomal polyadenylated rna in neurospora crassa.the sequence complexity of nuclear and polysomal polyadenylated rna in neurospora crassa has been investigated by an analysis of the kinetics of rna : cdna hybridizations. there are about 2000 different messenger rnas organized into three abundance classes of low, medium and high complexity which contain approx. 10, 150 and 1800 sequences, respectively. taking 1300 nucleotides as the average length of mrna, the total sequence complexity of polyadenylated polysomal rna was calculated to represent ...19806154479
nitrogen regulation of acid phosphatase in neurospora crassa.neurospora crassa possesses a repressible acid phosphatase with phosphodiesterase activity which appears to permit it to utilize ribonucleic acid as a phosphorus and as a nitrogen source. this acid phosphatase, which is specified by the pho-3 locus, is derepressed approximately eightfold during nitrogen limitation and to an even greater extent during phosphorus limitation, but is unaffected by sulfur limitation. derepression of the enzyme did not occur when adenosine 5'-monophosphate was the sol ...19806154048
glutamate synthase levels in neurospora crassa mutants altered with respect to nitrogen metabolism.glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. glutamate synthase activity has been determined in a number of neurospora crassa mutant strains with various defects in nitrogen metabolism. of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutam ...19816152851
genetic and biochemical characterization of glutamine synthetase from neurospora crassa glutamine auxotrophs and their this paper we present the isolation and characterization of glutamine auxotrophs of neurospora crassa and their revertants. the results show that although various enrichment procedures were used, we found only two types of auxotrophs. genetic crosses performed between the different mutants showed that the mutations responsible for their phenotypes were highly linked and probably affected the same gene. the biochemical characterization of the glutamine synthetase polypeptides of the different ...19836139363
neurospora crassa mutants deficient in asparagine synthetase.neurospora crassa mutants deficient in asparagine synthetase were selected by using the procedure of inositol-less death. complementation tests among the 100 mutants isolated suggested that their alterations were genetically allelic. recombination analysis with strain s1007t, an asparagine auxotroph, indicated that the mutations were located near or within the asn gene on linkage group v. in vitro assays with a heterokaryon indicated that the mutation was dominant. thermal instability of cell ex ...19836137480
neurospora crassa mutant impaired in glutamine regulation.the final products of the catabolism of arginine that can be utilized as nitrogen sources by neurospora crassa are ammonium, glutamic acid, and glutamine. of these compounds, only glutamine represses arginase and glutamine synthetase. we report here the isolation and characterization of a mutant of n. crassa whose arginase, glutamine synthetase, and amino acid accumulations are resistant to glutamine repression (glni). this mutant has a greater capacity than the wild type (glns) to accumulate mo ...19836134713
effect of the nitrogen source on glutamine and alanine biosynthesis in neurospora crassa. an in vivo 15n nuclear magnetic resonance study.the influences of different nitrogen sources on the relative rates of biosynthesis of glutamine and alanine have been studied by 15n nuclear magnetic resonance spectroscopy of intact neurospora crassa mycelia suspensions. the rate of glutamine synthesis was fastest after growth in media deficient in free ammonium ion, whereas it was slowest following growth in media containing both glutamic acid and glutamine. the reverse trend was observed for the biosynthesis of alanine. a competition between ...19826128342
regulation of l-amino acid oxidase and of d-amino acid oxidase in neurospora crassa.neurospora crassa possesses an inducible l-amino acid oxidase that is expressed only when cells are derepressed for nitrogen in the presence of an amino acid. enzyme synthesis requires both induction by an amino acid and simultaneous nitrogen catabolite derepression. carbon limition in the presence of an amino acid does not permit induction of l-amino acid oxidase. the nit-2 gene is a major regulatory locus which is believed to mediate nitrogen catabolite repression in neurospora. mutants of nit ...19826125872
some kinetic properties of the tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa.the steady-state kinetic properties of purified tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa were examined. the results suggest that the enzyme obeys a rapid-equilibrium ordered mechanism, in which phosphoenolpyruvate is the first substrate to bind and 3-deoxy-d-arabino-heptulosonate 7-phosphate is the second product to be released, rather than a ping pong mechanism as has been reported previously. the inhibition by tryptophan was found to be p ...19816122442
physiology of ammonium assimilation in neurospora neurospora crassa the assimilation of high and low concentrations of ammonium occurs by two different pathways. when the fungi are growing exponentially on ammonium excess, this compound is fixed by a glutamic dehydrogenase and an octameric glutamine synthetase (gs). the synthesis of this gs polypeptide (beta) is regulated by the nitrogen source present in excess; being higher on glutamate, intermediate on ammonium, and lower on glutamine. when n. crassa is growing in fed-batch ammonium-limit ...19826120927
the purification and molecular properties of the tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa.neurospora crassa contains three isoenzymes of 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase, which are inhibited by tyrosine, tryptophan and phenylalanine respectively, and it was estimated that the relative proportions of the total activity were 54%, 14% and 32% respectively. the tryptophan-sensitive isoenzyme was purified to homogeneity as judged by polyacrylamide-gel electrophoresis and ultracentrifugation. the tyrosine-sensitive and phenylalanine-sensitive isoenzymes were only partia ...19816119978
the effect of essential amino acid deprivation on poly(a) metabolism in neurospora crassa.poly(a) messenger rna was isolated from a methionine auxotroph of neurospora crassa grown to exponential and early stationary phases, and from mycelia deprived of the essential amino aid. the polyadenylate regions were isolated from the mrna preparations by enzymatic digestion and affinity chromatography, and their lengths determined by electrophoresis on 10% acrylamide/90% formamide gels. there was no significant difference in the lengths of the poly(a) regions between exponential and early sta ...19816115674
isolation and characterization of guanine auxotrophs in neurospora ad-9 strain of neurospora crassa was mutagenized with ethylmethane sulfonate (5%) and selected for guanine auxotrophy. the resultant double adenine plus guanine mutant was backcrossed with wild type and a single guanine auxotroph was isolated from the progeny. in vitro assays indicated that the mutant had gmp synthetase activity comparable with wild type, but was completely lacking of imp dehydrogenase activity. the guanine requirement can therefore be explained by the mutant's inability to c ...19806113044
effect of the gln-1b mutation on nitrogen metabolite repression in neurospora neurospora crassa, synthesis of the enzymes of nitrate assimilation, nitrate reductase and nitrite reductase, was repressed by the presence of ammonium, glutamate, or glutamine. this phenomenon was a manifestation of the regulatory process termed nitrogen metabolite repression whereby alternative pathways of nitrogen acquisition are not expressed in cells enjoying nitrogen sufficiency. however, the glutamine synthetase mutant gln-1b had derepressed levels of the nitrate assimilation enzymes. ...19816109713
the role fo glutamine synthetase and glutamine metabolism in nitrogen metabolite repression, a regulatory phenomenon in the lower eukaryote neurospora crassa.growth of neurospora crassa on media containing nh4+ leads to the repression of a variety of permeases and alternative pathways which would generate nh4+, so called "ammonium repression." the mutant am2 which lacks nadp-gdh is not subject to ammonium repression of nitrate reductase or urea permease, but like the wild type has repressed levels of these systems when grown in the presence of proline, glutamate or glutamine. the glutamine synthetase (gs) mutant gln-1a has derepressed levels of the a ...19806109228
physiological characterization of a neurospora crassa mutant with impaired regulation of nitrate reductase.this report describes the isolation and characterization of a neurospora crassa mutant with an impaired regulation of nitrate reductase. glutamine, which prevents the induction of nitrate reductase in n. crassa, did so relatively ineffectively in this mutant. the mutation did not affect the regulation of all enzymes regulated by "nitrogen metabolite regulation"; it did affect the regulation of nitrate reductase, nitrite reductase, histidase, and acetamidase, as well as that of thiourea sensitivi ...19806107286
[the mechanism of action of the herbicide n-(phosphonomethyl)glycine: its effect on the growth and the enzymes of aromatic amino acid biosynthesis in escherichia coli (author's transl)].n-(phosphonomethyl) glycine prolongates the lag-phase and inhibits the growth rate of escherichia coli, salmonella typhimurium and pseudomonas aureofaciens. the eucaryotes saccharomyces cerevisiae and neurospora crassa are not inhibited. the effect of growth inhibition in an e. coli culture depends on the time of the herbicide addition and no cells showing resistance against it are observed. the inhibitory effect can be overcome completely by a mixture of phenylalanine, tyrosine and tryptophan. ...19806105996
heterogeneity of glutamine synthetase polypeptides in neurospora crassa.purified preparations of neurospora crassa glutamine synthetase contain two nonidentical polypeptides that can be separated by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and 7 m urea. these polypeptides are synthesized both in vivo and in a heterologous cell-free protein-synthesizing system. the data presented indicate that both polypeptides contain an active site for glutamine synthetase activity and suggest that there is not a precursor-product relationship betwee ...19806102088
relation between structure and function of neurospora crassa glutamine synthetase. 19806101946
deficient cyclic adenosine 3',5'-monophosphate control in mutants of two genes of neurospora crassa.strains of neurospora crassa mutant in either of two genes, crisp-1 (cr1) and frost (fr), showed no increase of cyclic adenosine 3',5'-monophosphate (cyclic amp) levels when subjected to several treatments which produce large increases of cyclic amp in wild-type neurospora. evidently, the previously reported deficiencies of adenylate cyclase in these mutants were sufficient to block the normal increases. this fact suggests that both mutants could be used to help determine which control phenomena ...19816100957
preparation of immobilized nad glycohydrolase from neurospora crassa conidia by hydrophobic interaction--characteristics of the enzyme derivative.nad glycohydrolase from neurospora crassa conidia has been immobilized by hydrophobic interaction on sepharose 4b beads coated with propyl residues through cnbr activation. the bond resulted stable under a wide range of conditions (ionic strength, temperature, ph). as a result of immobilization the ph optimum for catalytic activity shifted by about 0.2 ph unit in the acidic direction, to lie between 7.5 and 7.3. the stability of the enzymatic activity was largely enhanced by effect of immobiliza ...19846096842
transcriptionally active chromatin is sensitive to neurospora crassa and s1 nucleases.we have examined the distribution of neurospora crassa and s1 nuclease cleavage products in the chromatin of the 87a7 heat shock locus of drosophila melanogaster. both of these nucleases generate single and double-strand breaks in chromatin at specific sites in the 87a7 locus. before heat induction, we find that the 5' ends of the two 87a7 hsp 70 genes contain n. crassa and s1 nuclease hypersensitive sites, while there are only a few cleavage products from elsewhere in the locus. with n. crassa ...19846096552
transformation of neurospora crassa with recombinant plasmids containing the cloned glutamate dehydrogenase (am) gene: evidence for autonomous replication of the transforming plasmid.we have characterized neurospora crassa transformants obtained with plasmid pjr2, which consists of the neurospora glutamate dehydrogenase (am) gene cloned in puc8 and an am132 host strain which contains a deletion encompassing the cloned fragment. every one of 33 transformants tested showed extreme meiotic instability: less than 1 or 2% am+ progeny were obtained in initial or successive backcrosses between am+ transformants and am132 or in intercrosses between am+ progeny. furthermore, am+ prog ...19846095037
the mitochondrial genome of the fission yeast schizosaccharomyces pombe. 2. localization of genes by interspecific hybridization in strain ade7-50h- and cloning of the genome in small fragments.a series of 18 small overlapping restriction fragments has been cloned, covering the complete mitochondrial genome of schizosaccharomyces pombe. by hybridizing mitochondrial gene probes from saccharomyces cerevisiae and neurospora crassa with restriction fragments of schizosaccharomyces pombe mitochondrial dna, the following homologous genes were localized on the mitochondrial genome of s. pombe: cob, cox1, cox2 and cox3, atpase subunit 6 and 9 genes, the large rrna gene and both types of open r ...19846094974
organization of the ribosomal ribonucleic acid genes in various wild-type strains and wild-collected strains of neurospora.the organization of the ribosomal dna (rdna) repeat unit in the standard wild-type strain of neurospora crassa, 74-or23-1a, and in 30 other wild-type strains and wild-collected strains of n. crassa, . tetrasperma, n. sitophila, n. intermedia, and n. discreta isolated from nature, was investigated by restriction enzyme digestion of genomic dna, and probing of the southern-blotted dna fragments with specific cloned pieces of the rdna unit from 74-or23-1a. the size of the rdna unit in 74-or23-1a wa ...19846092870
analysis of the structure and transcription of the aro3 cluster gene in schizosaccharomyces selecting activities to complement escherichia coli aro mutations, a gene responsible for the biosynthesis of aromatic amino acids in schizosaccharomyces pombe (aro3) was cloned into pbr322. three independent clones named pfna1, pfna2 and pfna3 were obtained. pfna1 could complement e. coli arod only, whereas the other two plasmids were able to complement both arod and aroe. the aro3 locus of s. pombe was found to be a gene cluster which can be subdivided into five complons, a through e (strau ...19846092844
inhibition of superoxide dismutase by nitroprusside and electron spin resonance observations on the formation of a superoxide-mediated nitroprusside nitroxyl free radical.nitroprusside appears to inhibit the known types of superoxide dismutases irrespective of their metal prosthetic group and regardless of the source from which the enzymes were isolated. thus the copper-zinc enzyme from bovine erythrocyte or neurospora crassa behaved identically as did the manganese enzymes from escherichia coli or red alga and the iron enzyme from e. coli and a blue-green alga. the inhibition was dose dependent with a ki = 2.5 x 10(-5) for nitroprusside. nitroprusside does not b ...19846092342
heavily methylated amplified dna in transformants of neurospora crassa.substantial dna methylation occurs in higher eukaryotes and in some cases affects gene expression. however, the genomes of some fungi, drosophila and other lower eukaryotes have an extremely low 5-methylcytosine content, suggesting that dna methylation might not have a general role in gene control. we have now found heavy methylation of transforming dna which has become stably amplified in complex tandem arrays in the fungus neurospora crassa. rearranged amplified arrays of this type have not pr ...20066088987
three subunit proteins of membrane enzymes in mitochondria of neurospora crassa contain a pantothenate derivative.three proteins of the inner mitochondrial membrane of neurospora crassa were found to be covalently modified with a derivative of pantothenic acid. one of these proteins is a subunit of cytochrome c oxidase and two are subunits of the atpase-atp synthase. cells of a pantothenate auxotroph of n. crassa were labeled with [14c]pantothenic acid, and mitochondrial proteins containing radiolabeled pantothenate were detected by electrophoresis of detergent-solubilized mitochondria. mitochondria from ce ...19846088512
the dna sequence and genetic organization of a neurospora mitochondrial plasmid suggest a relationship to introns and mobile elements.we have determined the complete 3581 bp sequence of the mitochondrial plasmid from neurospora crassa strain mauriceville-1c. the plasmid contains a long open reading frame that is expressed in its major transcript and could encode a hydrophilic protein of 710 amino acids. two characteristics of the plasmid--codon usage and the presence of conserved sequence elements--suggest that it is related to group i mtdna introns. the major transcripts of the plasmid are approximately full-length, colinear ...19846088081
intramolecular recombination as a source of mitochondrial chromosome heteromorphism in neurospora.approximately 20% of the genome is missing and an equivalent amount is under-represented in the mitochondrial chromosome population of a stopper (stp) mutant of neurospora crassa during the stopped phase of its cyclical growth pattern. at this stage, a 21 kb (7.2 mu) circular molecule, one-third the length of the normal chromosome, is the predominant form. a complementary 43 kb (14.6 mu) circle appears upon resumption of growth. the circles arise by reciprocal recombination at or near directly r ...19846088067
genetic control of allelic recombination at the histidine-3 locus of neurospora crassa. 19676082625
argininosuccinate synthetase of neurospora crassa. 19676078087
photoreactivating enzyme from neurospora crassa. 19676077698
actinomycin d-induced phenotypic reversion in neurospora crassa. 19676077527
the serine biosynthetic pathway in neurospora crassa. 19676077050
altered aspartate transcarbamylase of neurospora crassa responsible for a suppressor effect. 19676066249
ultrastructural studies of microconidium formation in neurospora crassa.microconidiating cultures of "peach-fluffy" (pe, fl; y8743m, l; fgsc #569) were fixed at various times after the initiation of growth and examined with an electron microscope. hyphae from which microconidia form are markedly vacuolated and show a much more extensive system of rough endoplasmic reticulum than young vegetative hyphae. a bulge in the hypha presages the start of microconidium formation, followed by the rupture of the outermost wall layers. a thick collar forms around the protruding ...19676066052
3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthetase as an "allosteric" function and ligand interactions with this enzyme from neurospora crassa. 19676064585
synchronous mitochondrial division in neurospora crassa.samples of mycelium of neurospora crassa of known age were harvested from agar plates and examined with the electron microscope. the relative volume of the mitochondria was determined for mycelium of different ages. the volume measurements indicated that the mitochondria were dividing synchronously in fronts 6, 13, and 22(1/2) hr behind the growing hyphal tips. the sequence of mitochondrial division is hypothesized to include mitochondrial cupping followed by division which results in closely as ...19676064362
ultraviolet-sensitive mutants in neurospora crassa. 19676061668
lepid content of conidia of neurospora crassa. 19676060645
properties of a phosphatidylmonomethylethanolamine n-methyl-transferase from neurospora crassa. 19676060457
relations between complementation patterns and genetic alterations in nitrous acid-induced ad-3b mutants of neurospora crassa. 20006059024
allelic complementation among nitrous acid-induced ad-3b mutants of neurospora crassa. 20006059023
mutation-induced and nuclear inactivation in neurospora crassa using radiations with different rates of energy loss. 19676058651
multiple alterations in metabolite uptake in a mutant of neurospora crassa.a temperature-conditional lethal mutant of neurospora crassa, un-t (55701), was resistant to neutral amino acid analogues by virtue of a decreased ability to transport these analogues and their natural congeners across the cell membrane. the uptake of acidic, but not basic, amino acids was also impaired, as was the uptake of potassium ions. after preincubation above the tolerated temperature, the ability to take up a still wider variety of metabolites was greatly reduced. protoplasts of the muta ...19676057809
amino acid substitutions in mutant forms of histidinol dehydrogenase from neurospora crassa.amino acid changes in the enzyme l-histidinol dehydrogenase (l-histidinol-nad oxidoreductase, ec have been determined between the wild-type neurospora crassa and two temperature-sensitive mutants. comparison was made between amino acid analyses of peptides of differing electrophoretic and chromatographic mobilities resulting from tryptic and chymotryptic digestion of protein from wild-type and mutant k26, and wild-type and mutant k445 strains, respectively. the analyses demonstrate the ...19676056636
Displaying items 3501 - 3600 of 5889