PMID(sorted descending)
specificity of uracil uptake in neurospora crassa.the specificity of uracil uptake was investigated in germinating wild-type conidia of neurospora crassa. from comparative inhibition studies, several generalizations concerning the specificity of uracil uptake can be made. (i) the tautomeric forms of uracil analogs is an important determinant of recognition by the uptake system. (ii) substituents at the 5 position of the pyrimidine ring may impose steric constraints on binding. (iii) the presence of a negative charge results in the loss of recog ...1979156718
mechanisms controlling the two phosphate uptake systems in neurospora crassa.the development of the high-affinity and low-affinity phosphate uptake systems of neurospora crassa has been followed during germination and early growth. the ratio between the activities of the two systems became constant by the time exponential growth began, although the value of this ratio depended on the external phosphate concentration. the regulatory mechanisms controlling the systems were investigated by following the changes that resulted when exponentially growing germlings adapted to o ...2003156717
mobilization of sequestered metabolities into degradative reactions by nutritional stress in neurospora.the pools of arginine and ornithine rapidly disappear during nitrogen starvation of neurospora crassa. much of this disappearance can be accounted for by degradation catalyzed by preexisting catabolic enzymes. purine degradation is also initiated by nitrogen metabolic stress. mobilization of these compounds into degradative reactions does not appear to be a general response to nutritional stress since neither carbon starvation nor inhibition of protein synthesis elicits this response. it is sugg ...2003156715
split gene for mitochondrial 24s ribosomal rna of neurospora crassa.the 60 kb circular mitochondrial genome of n. crassa has previously been shown to contain a single transcription unit for 17s and 24s rrna mapping within the largest eco ri fragment e1 (19.6 kb). this fragment was isolated from uncloned mitochondrial dna and further analyzed by cleavage with restriction endonucleases hind ii, hind iii, bam hi, pvu ii and bgi i, and by electron microscopy of rrna/dna hybrids. the resulting map shows a 2.3 kb intervening sequence interrupting the gene for 24s rrna ...1979156584
the biosynthesis of the free sterols and sterol esters of neurospora crassa.the composition of the free and esterified sterols in neurospora crassa was examined as a function of incubation time in starvation medium containing [2-14c]mevalonic acid. the 14c incorporation was monitored in nuclear methylated and 4,14-desmethyl sterol fractions. after 7 h incubation, sterol esterification had increased from an initial 5% in the log phase culture to 48% of the total sterol pool, with a concomitant decrease in free sterols. the relationship of the free and esterified sterol c ...1979156577
purification of the arom multienzyme aggregate from euglena gracilis.the arom multienzyme complex that catalyzes steps two through six in the prechorismate polyaromatic amino acid biosynthetic pathway has been purified up to 2000-fold from euglena gracilis. the native arom aggregate has a molecular weight of approx. 249 000 based on a sedimentation coefficient of 9.5 and stokes radius of 60 angstrom. a comparison between the arom aggregates of neurospora crassa and euglena gracilis and the possible phylogenetic relationships between the organisms are discussed.2003156559
laboratory of physiological chemistry, state university groningen, obtain more information about the arrangement of hind iii restriction fragments in the trna-rrna region of the neurospora crassa mitochondrial (mt) dna we have cleaved the mtdna with hpa i and hind ii. we could construct additional cleavage maps for these enzymes. hybridization of rrnas to hind ii fragments confirmed the existence of an intervening region of about 2,300 basepairs in the 24s rrna (hahn et al., cell, in press). about seven trna genes, among which the genes for trna1ser and trna ...1979156351
constitutive expression in escherichia coli of the neurospora crassa structural gene encoding the inducible enzyme catabolic neurospora crassa the qa-2 gene, which encodes catabolic dehydroquinase, is under positive control exerted by the inducer quinic acid and an activator protein encoded in the closely linked qa-1 gene. in order to determine if this regulatory mechanism is maintained when the qa-2 gene is cloned on a recombinant plasmid and expressed in escherichia coli, molecular cloning experiments have been performed using dna isolated from a qa-1+ (inducible), a qa-1c (constitutive) and two qa-1 (non-inducib ...1979156301
mutagenicity and mutagenic specificity of metronidazole and niridazole in neurospora crassa.mutagenicity and mutagenic specificity of niridazole and metronidazole, two chemotherapeutic agents used in the treatment of human parasitic diseases, were studied with the ad-3 test system of neurospora crassa. the results show that neither compound is mutagenic in resting conidia. in growing vegetative cells, however, both compounds are mutagenic in neurospora crassa. genetic analysis of the mutants indicate that niridazole induces predominantly base-pair substitution mutations. none of the ni ...1979156240
comparison of inducible and constitutive kynureninases of neurospora crassa.two types of kynureninase were isolated from neurospora crassa ifo 6068. the formation of one of them, which was separated from the inducible kynureninase by deae-cellulose chromatography, was independent of the presence of tryptophan in the growth medium. ouchterlony double-diffusion analysis and immunochemical titration indicated that the constitutive-type enzyme is immunologically different from the inducible enzyme. we confirmed by a selective assay method with antiserum that the addition of ...1979156178
synthesis of a larger precursor for the proteolipid subunit of the mitochondrial atpase complex of neurospora crassa in a cell-free wheat germ system. 1979156127
isolation and genetic analysis of nuclease halo (nuh) mutants of neurospora crassa.nuclease halo (nuh) mutants of the ascomycete neurospora crassa have been isolated which are characterized reduced release of deoxyribonuclease (dnase) activities from colonies grown on sorbose-containing agar media. to identify nuh mutants, mutagenized isolates were transferred to commercial dnase test agar, or grown on minimal medium and then overlayed with agar that contained heat-denatured dna. dnase activity was visualized by acid precipitation which produced clear rings of digestion (haloe ...2003155773
inactivation of neurospora crassa conidia by singlet molecular oxygen generated by a photosensitized reaction.photodynamic damage of neurospora crassa conidia was studied in the presence of the photosensitizing dye, toluidine blue o. conidia which germinated to form colonies decreased in number as irradiation time became longer. the photoinactivation of conidia was suppressed by azide, bovine serum albumin, and histidine, and was stimulated in deuterium oxide. wild-type conidia were less sensitive to the irradiation than albino conidia. in the wild-type, carotenoid-enriched conidia were more resistant a ...1979155692
transmission of mitochondrial deoxyribonucleic acid in neurospora crassa sexual crosses.neurospora crassa mitochondrial deoxyribonucleic acid shows strict uniparental inheritance in sexual crosses, with a notable absence of mixtures and recombinant types that appear frequently in heteroplasmons.1979155689
arrangement of the genes coding for ribosomal ribonucleic acids in neurospora crassa.we have cloned and characterized neurospora crassa ribosomal deoxyribonucleic acid (rdna). the rdna is found as a tandemly repeated 6.0-megadalton sequence. we have mapped a portion of the rdna repeat unit with respect to its sites for 13 restriction endonucleases and defined those regions coding for the 5. 8s, 17s, and 26s ribosomal ribonucleic acids (rrna's). we have also isolated several clones containing 5s rrna sequences. the 5s rrna coding sequences are not found within the rdna repeat uni ...1979155688
nitrogen metabolite repression of nitrate reductase in neurospora crassa.the effect of different nitrogen compounds on the induction of reduced nicotinamide adenine dinucleotide phosphate-nitrate reductase was examined in neurospora crassa. whereas in the wild-type strain several amino acids and ammonia inhibit the formation of nitrate reductase, only glutamine, cysteine, and histidine are shown to inhibit the synthesis of nitrate reductase in a glutamine-requiring auxotroph. none of the amino acids inhibited nitrate reductase activity in vitro. the effects of cystei ...1979155687
characterization of the carbohydrate component of fraction i in the neurospora crassa cell wall.the carbohydrate portion of fraction i of the neurospora crassa cell wall has been analyzed for sugar composition by gas-liquid chromatography and colorimetric methods. the analysis was performed comparatively in a wild-type strain (rl 3-8a) and three morphological mutants: scumbo (fgsc 49), peak-2a (a mutant known to be allelic to biscuit), and ragged (fgsc 296). fraction i of all strains studied contains glucose, mannose, and galactose as the main sugars. uronic acids and amino sugars are also ...1979155686
literature survey of bacterial, fungal, and drosophila assay systems used in the evaluation of selected chemical compounds for mutagenic activity.literature reports were surveyed, with results noted from experiments in seven nonmammalian assay systems used for the detection of mutagenicity or other related genetic effects. a comparison was made of the activities of 54 selected noncarcinogens, procarcinogens, and ultimate carcinogens as revealed by these test systems. of the compounds tested, 49 (91%) were active in one or more of the assays, and 42 (78%) were positive in at least one system without having to be metabolically activated. in ...1979155170
the effects of vanadate on the plasma membrane atpase of neurospora crassa. 1979155060
mediated mutagenesis of dimethylnitrosamine in neurospora crassa by various metabolic activation systems.four metabolic activation systems (growth mediated mycelium extract mediated, host mediated, and organ homogenate mediated) were used to study the mutagenic activity of dimethylnitrosamine (dmn) in both forward and reverse mutation systems in the ad-3 (adenine-3) region of neurospora crassa. dmn was not mutagenic in neurospora if conidia alone were treated. it was highly mutagenic, however, if conidia were treated with this compound under any of the four activation systems. quantitative differen ...1979154971
photosensitivity of respiration in neurospora mitochondria. a protective role for carotenoid.1. the effect of visible light on respiratory activity was studied in two strains of neurospora crassa, one a wild-type strain able to synthesize carotenoid and the other an albino mutant lacking carotenogenic activity. light had no effect on growth under the conditions studied, but inhibited respiration of hyphal suspensions. the degree of inhibition being dependent on the carotenoid content of the hyphae. 2. in studies of respiration of isolated mitochondria, three types of photosensitive site ...1978154887
some properties of vacuoles isolated from neurospora crassa slime variant.a method for the isolation of vacuoles based on polybase induced lysis of protoplasts of the cell wall deficient neurospora crassa slime variant is described. isolated vacuoles are characterized by 12 to 50 times increased specific activities of several hydrolases as compared with the total homogenate of protoplasts. total alpha-amino nitrogen, arginine, and polyphosphate are also greatly enriched in these vacuoles. vacuoles are equipped with a permease for the transport of basic amino acids acr ...1979154878
interesting and unusual features in the sequence of neurospora crassa mitochondrial tyrosine transfer rna.the mitochondrial tyrosine trna from neurospora crassa has been sequenced and found to have several interesting features: (i) it resembles prokaryotic rather than eukaryotic tyrosine trnas in that it possesses a large variable loop (loop iii); moreover, it can be quantitatively aminoacylated by escherichia coli tyrosyl-trna synthetase but not by yeast tyrosyl-trna synthetase. (ii) this trna differs from all trna's sequenced to date in lacking the a residue at position 14 and the constant purine ...1979154673
alkaline deoxyribonucleases released from neurospora crassa mycelia: two activities not released by mutants with multiple sensitivities to mutagens.three major alkaline deoxyribonuclease (dnase) activities have been identified in sorbose-containing liquid culture medium in which wild-type neurosporacrassa were grown: dnase a, a ca++dependent endonuclease of molecular weight 65,000 daltons which has no specificity for single- or double-stranded dna (ss-dna or ds-dna) and no activity with rna; dnase b, a mg++-dependent single-strand specific exonuclease of molecular weight 78,000 daltons active with both ss-dna and rna; dnase c, a divalent me ...1979154656
comparison of the genetic activity of 5-nitroimidazole derivatives in escherichia coli, neurospora crassa, saccharomyces cerevisiae and drosophila melanogaster.5-nitroimidazoles, including metronidazole (compound 1) and 3 analogues (compounds 2, 3 and 4) of actual or potential chemotherapeutic use were assayed for genetic activity in test systems detecting forward and back mutations in escherichia coli k-12/343/113, forward mutations in neurospora crassa heterokaryon 12, mitotic gene conversion in the heteroallelic diploid yeast strain saccharomyces cerevisiae d4 and sex-linked recessive lethals in drosophila melanogaster. whereas metronidazole exhibit ...1979154545
circadian rhythms in neurospora crassa: effects of unsaturated fatty acids.employing a fatty acid-requiring strain (bd csp cel) of neurospora crassa, the 21.5-h period of the circadian spore-forming rhythm was manipulated by fatty acid supplementation. the addition to the medium of an unsaturated fatty acid (oleic, linoleic, or linolenic acid) lengthened the period to 26, 40, or 33 h, respectively. ther period-lengthening effect of linoleic acid was proportional to its concentration up to 1.3 x 10(-4) m, and also was reversed by the addition to the medium of a saturate ...1979154511
selection of succinic dehydrogenase mutants of neurospora crassa.a method is described which permits the selection of mutants of neurospora crassa that are deficient in succinic dehydrogenase activity. the method relies on the observation that succinic dehydrogenase-deficient strains fail to reduce the dye nitrotetrazolium blue when overlaid with the dye in the presence of succinate and phenazine methosulfate. wild-type colonies reduced the dye and turned blue, whereas mutant colonies remained colorless. in this communication we present studies of a mutant, s ...1979154510
transcription and translation in e. coli of hybrid plasmids containing the catabolic dehydroquinase gene from neurospora crassa.two hybrid plasmids which carry the gene for neurospora crassa catabolic dehydroquinase (c-dhqase) and complement an arod6 (dehydroquinase-deficient) auxotroph of escherichia coli have been analyzed. one of these contains a 2.9 kilobase (kb) fragment cloned in the hindiii site of plasmid pbr322 (pvk57) and the other contains a 6.8 kb fragment cloned in the psti site (pvk88). restriction enzyme mapping of these plasmids has demonstrated that the 2.9 kb fragment is totally contained within the 6.8 ...1978154430
organization of the ribosomal ribonucleic acid gene cluster of neurospora crassa by means of restriction endonucleases and cloning in bacteriophage lambda [proceedings]. 1978154424
isolation of neurospora crassa-bovine l-glutamate dehydrogenase hybrids [proceedings]. 1978154423
ligand-induced changes in the accessibility of sulphydryl groups of neurospora crassa pyruvate kinase. 2003154420
the dicyclohexylcarbodiimide-binding protein of the mitochondrial atpase complex from neurospora crassa and saccharomyces cerevisiae. identification and isolation.incubation of mitochondria from neurospora crassa and saccharomyces cerevisiae with the radioactive atpase inhibitor [14c]dicyclohexylcarbodiimide results in the irreversible and rather specific labelling of a low-molecular-weight polypeptide. this dicyclohexylcarbodiimide-binding protein is identical with the smallest subunit (mr 8000) of the mitochondrial atpase complex, and it occurs as oligomer, probably as hexamer, in the enzyme protein. the dicyclohexylcarbodiimide-binding protein is extra ...1979154405
sterol content and enzyme defects of nystatin-resistant mutants of neurospora crassa.non-saponifiable cell extracts of wild type and sterol mutants of n. crassa were analysed by means of gas-liquid chromatography. the wild-type contained ergosterol and episertol in a 10:1 ratio. none of the mutants was able to synthesize ergosterol. three of the mutants carry single recessive gene mutations cauisng blocks in the terminal steps of ergosterol biosynthesis: erg-1 has an inactive delta 8 leads to delta 7 isomerase erg-2 has an inactive 24(28) hydrogenase, and erg-4 has an inactive c ...2003154056
reversion and interallelic complementation at four urease loci in neurospora crassa.analysis of heat stability of urease in extracts of 24 revertants, six for each of four ure loci, revealed that at least one revertant for each locus had a heat stability about one-third that of wild type. similar results were obtained with urease formed by interallelic complementation at the ure-2 and ure-4 loci, but interallelic complementation at the ure-1 and ure-3 loci produced insufficient urease activity for analysis. the data are interpreted to suggest, as a tentative model, a structural ...2003154055
biosynthesis of glycogen in neurospora crassa. kinetic mechanism of udp-glucose: glycogen 4-alpha-glucosyltransferase.the kinetic mechanism of glycogen synthase [udp-glucose: glycogen 4-alpha-glucosyltransferase, ec], glucose-6-p-dependent form, from neurospora crassa has been investigated by initial velocity experiments and studies with inhibitors in the presence of sufficient levels of glucose-6-p. the rate equation was different from those of common two-substrate systems because one of the substrates, glycogen, is also a product. the reaction rates were determined by varying the concentration of one ...2003153901
nature of 6-methylpurine inhibition and characterization of two 6-methylpurine-resistant mutants of neurospora crassa.6-methylpurine, an analog of adenine, inhibits the growth of neurospora crassa. from kinetic studies it was found that 6-methylpurine is converted to its nucleotide form by adenine phosphoribosyltransferase (ec, and inhibits the de novo purine biosynthesis. adenine relieves the growth inhibition caused by 6-methylpurine, whereas hypoxanthine is not very effective. studies dealing with hypoxanthine utilization in the presence of 6-methylpurine indicated a severely reduced uptake of hypox ...1979153898
differential deoxyribonucleic acid synthesis during microcycle conidiation in neurospora conidia of neurospora crassa germinating at 25 degrees c, dna synthesis measured by incorporation of tritiated adenosine reaches a maximum soon after the outgrowth of the germ tube (6--7 h after inoculation). in conidia heat-treated at 46 degrees c (for 15 h), a maximum of incorporation of the dna precursor occurs already 1 h after inoculation, then the incorporation progressively declines until the end of the heat-shock. when such conidia are shifted to 25 degrees c, a maximum of dna synthes ...2003153737
mutagenicity and mutagenic specificity of metronidazole and niridazole in neurospora crassa.mutagenicity and mutagenic specificity of niridazole and metronidazole, two chemotherapeutic agents used in the treatment of human parasitic diseases, were studied with the ad-3 test system of neurospora crassa. the results show that neither compound is mutagenic in resting conidia. in growing vegetative cells, however, both compounds are mutagenic in n. crassa. genetic analysis of the mutants indicated that niridazole induces predominantly base-pair substitution mutations. none of the niridazol ...1978153406
isolation and characterization of glycerol-3-phosphate dehydrogenase-defective mutants of neurospora crassa.three glycerol-nonutilizing mutants deficient in the mitochondrial glycerol-3-phosphate (g3p) dehydrogenase (ec were isolated from inl(ts) derivatives of neurospora crassa following inositolless death at elevated temperatures on minimal glycerol medium. these mutants failed to grow on glycerol as a sole carbon source, but could grow on acetate, glucose, or mannitol media and were female fertile in genetic crosses, thereby distinguishing them from the previously reported polyol-protoper ...1978152757
specificity of nucleoside transport in neurospora crassa.the specificity of nucleoside uptake in germinating conidia of neurospora crassa was investigated by examining the kinetics of [2-14c]uridine and [8-14c]-adenosine uptake in the wild-type, ad-8, and ud-1 pyr-1 strains. the results obtained strongly indicate that nucleoside transport in n. crassa is mediated solely by a general transport system which accepts both purine and pyrimidine nucleosides. studies directed at characterizing the specificity of the transport system indicate that general str ...1978152756
purification of cytochrome b from neurospora crassa and other sources. 2003152379
nuclear division cycle in germinating conidia of neurospora crassa.a temperature-sensitive mutant has been shown to be blocked at a specific point in the nuclear division cycle: just before the initiation of dna synthesis at the time when the spindle pole bodies have duplicated but not separated. the metabolic activities of conidia of this mutant strain at the nonpermissive temperature have led us to conclude that the nuclei in a population of dormant conidia are arrested at various points in the nuclear division cycle. this conclusion is substantiated by the a ...1978152308
isolation and biochemical properties of two types of microbody from neurospora crassa cells.cells of the neurospora crassa slime mutant grown in sucrose medium exhibited low activities of glyoxysomal marker enzymes isocitrate lyase (icl), malate synthetase (ms), and malate dehydrogenase. transfer of the cells to a medium containing acetate as sole carbon source ("acetate medium") induced a strong increase in the activities of these enzymes in both the soluble and the crude particulate cell fraction. soluble isocitrate lyase activity increased rapidly after a lag phase of about 45 minut ...1978152214
neurospora crassa mitochondrial transfer mitochondrial trna from neurospora crassa was characterized by base composition analysis, one- and two-dimensional gel electrophoreses and reversed-phase chromatography on rpc5. the guanosine + cytidine content was about 43%, as compared to 60% for cytoplasmic trna. the modified nucleoside content was low and about the same as that of total yeast mitochondrial trna, though the g + c content is very different. we found psi, t, hu, t6a, m1g, m2g, m22g. neither the eukaryotic "y" base, nor th ...1978152130
differential transcription of nonrepeated dnas in neurospora crassa mutants.transcriptional properties of an "albino" mutant, a "slime" mutant and a wild type strain of neurospora crassa have been compared by quantitative estimates of dna:rna hybridization. the rnas isolated from these strains were incubated with 32p-dna of the wild type strain. the dna:rna hybrids were isolated by chromatography on hydroxyapatite. 29--34% of the wild type 32p-dna hybridized with rna from all of the strains used. the dna sequences which gave a primary reaction with wild type rna (tr-dna ...1978151803
genetical and biochemical characterization of qa-3 mutants and revertants in the qa gene cluster of neurospora crassa.the qa-3 gene, one of the four genes in the qa gene cluster, encodes quinate (shikimate) dehydrogenase (quinate: nad oxidoreductase, er, the first enzyme in the inducible quinic acid catabolic pathway in neurospora crassa. genetic analyses have localized 26 qa-3 mutants at 11 sites on the aq-3 genetic map on the basis of prototroph frequencies. certain mutants, e.g., 336-3-10 and 336-3-3, are located at opposite ends of the qa-3 gene. data from four-point crosses (qa-1s mutant 124 x fi ...1978151647
effects of inhibitors on the plasma membrane and mitochondrial adenosine triphosphatases of neurospora crassa.a comparative study has been made of the effects of a variety of inhibitors on the plasma membrane atpase and mitochondrial atpase of neurospora crassa. the most specific inhibitors proved to be vanadate and diethylstilbestrol for the plasma membrane atpase and azide, oligomycin, venturicidin, and leucinostatin for mitochondrial atpase. n,n'-dicyclohexylcarbodiimide, octylguanidine, triphenylsulfonium chloride, and quercetin and related bioflavonoids inhibited both enzymes, although with differe ...2003151557
5' cap methylation of homologous poly a(+) rna by a rna (guanine-7) methyltransferase from neurospora crassa. 1978151539
distribution of ions in neurospora crassa determined by quantitative electron microprobe analysis. 2003151300
amino acid sequence of tyrosinase from neurospora crassa.the amino-acid sequence of tyrosinase from neurospora crassa (monophenol,dihydroxyphenylalanine:oxygen oxidoreductase, ec is reported. this copper-containing oxidase consists of a single polypeptide chain of 407 amino acids. the primary structure was determined by automated and manual sequence analysis on fragments produced by cleavage with cyanogen bromide and on peptides obtained by digestion with trypsin, pepsin, thermolysin, or chymotrypsin. the amino terminus of the protein is ac ...2002151279
adenylosuccinate amp-lyase (neurospora crassa). 2002151182
correlation of enzymatic activity and thermal resistance with hydration state in ungerminated neurospora conidia.ungerminated neurospora crassa conidia were incubated at 0, 50, and 100% relative humidity, giving rise to conidia in dry, quasi-dry, and wet hydration states, respectively. metabolic activity was detected by monitoring levels of reduced glutathione (gsh), oxidized glutathione (gssg), and the soluble-amino acid pools as a function of incubation time. wet conidia (approximately 65% water content) exhibited significant metabolic activity as evidenced by: (i) reduction of gssg to gsh, (ii) degradat ...2002151096
the biosynthesis of the mitochondrial adp, atp translocator.the biosynthesis of the adp,atp carrier was studied in mitochondria of neurospora crassa. the carrier was isolated as the carboxyatractylate-protein complex and characterized in dodecylsulphate/polyacrylamide gel electrophoresis to have a mr = 33 000. applying the inhibitors chloramphenicol for the intramitochondrial translation and cycloheximide for extramitochondrial translation, the site of synthesis of this polypeptide was found to be extramitochondrially located.1978150971
the nature of vitro assembly of neurospora crassa nadph-nitrate reductase (ec1.6.6.2) could be effected by combing the nitrate induced neurospora crassa mutant nit-1 with the extract of any known molybdenum-containing enzyme. the process involves the participation of a molybdenum-cofactor contributed by the molybdenum-enzyme fraction. this paper emphasizes two points: firstly, the indispensable role played by edta in the viability of mo-cofactor and secondly, the nature of mo-cofactor predicated by our pre ...1978150967
preparation and some properties of homogeneous neurospora crassa assimilatory nadph-nitrite reductase.the neurospora crassa assimilatory nadph-nitrite reductase (nad(p)h: nitrite oxidoreductase, ec, which catalyzes the nadph-dependent formation of ammonia from nitrite, has been purified to homogeneity as judged by polyacrylamide gel electrophoresis. the specific activity of the purified enzyme is 26.9 mumol nitrite reduced/min per mg protein, which corresponds to a turnover number of 7800 min(-1). the enzyme also has associated nadh-nitrite reductase, nadph-hydroxylamine reductase and n ...1978150863
presence of an actin-like protein in mycelium of neurospora crassa.addition of atp, cacl2, and kcl to supernatants prepared from mycelia of snowflake (strain 507), a morphological mutant of neurospora crassa, results in the formation of filaments 70 nm in diameter. the "decorated" appearance of these filaments after incubation with heavy meromyosin from rabbits suggests they are actin-like.1978150412
nitrogen regulation of amino acid catabolism in neurospora crassa.neurospora crassa can utilize numerous compounds including certain amino acids as a sole nitrogen source. mutants of the nit-2 locus, a regulatory gene which is postulated to mediate nitrogen catabolite repression, are deficient in the ability to utilize several amino acids as well as other nitrogen sources used by wild type. various enzymes involved in amino acid catabolism were found to be regulated in distinct ways. arginase, ornithine transaminase, and pyrroline-5-carboxylate dehydrogenase a ...2003150270
investigations on myo-inositol-1-phosphate synthase from the wild type and the inositol-dependent mutant of neurospora crassa.the inositol-dependent mutant of neurospora crassa lacks inositol-1-phosphate synthetase activity. this defect can be revorted by the addition of high-molecular dna isolated from the wild type. to elucidate the biochemical background of inositol dependence, inositol-1-phosphate synthetase was studied. a method has been developed fro the isolation of the enzyme from the wild type strain in 10 mg scale by salt fractionation, gel filtration and ion-exchange chromatography. the specific activity of ...2001150187
conditions of transformation by dna of neurospora crassa.the dna uptake and transformation of inositol-requiring recipient neurospora strains were investigated. exponentially growing cultures can accumulate 5-10 fold quantities of donor dna than older ones. the rate of dna uptake depends on the physiological state of the recipient cell, and on the molecular weight of donor dna. the exocellular dnase activity of the recipient culture may influence the dna uptake and the transformation process. "young" inositol-requiring neurospora crassa cultures can b ...1977150186
use of the spot, plate and suspension test systems for the detection of the mutagenicity of environmental agents and chemical carcinogens in neurospora crassa.n23 and n24, selected from hundreds of ad-3 mutants, have been used as testers for the spot, plate and suspension tests in neurospora crassa. these two testers are highly sensitive to mutagens and are revertible by a specific group of chemicals. n23 can be reverted from an adenine-dependence to adenine-independence by agents which cause base-pair substitutions whereas n24 can be reverted by frameshift mutagens. studies described here show that spot, plate and suspension tests using testers n23 a ...1978149924
nuclear suppressors of the [poky] cytoplasmic mutant in neurospora crassa. iii. effects on other cytoplasmic mutants and on mitochondrial ribosome assembly in [poky].we have previously isolated six non-allelic, nuclear mutations (sui loci) that partially suppress the growth, respiratory and cytochrome abnormalities of the extranuclear [poky] mutant. a comparison of the mitochondrial ribosome profiles of suppressed and unsuppressed [poky] strains revealed that five of the six suppressors alleviate at least partially the deficiency of mitochondrial small ribosomal subunits that is associated with the [poky] genotype. six independently isolated group 1 extranuc ...1978149910
control of the activity of intracellular nucleases in neurospora crassa. 1978149909
ageing of neurospora crassa. vii. accumulation of fluorescent pigment (lipofuscin) and inhibition of the accumulation by nordihydroguairetic acid.continuous administration of the antioxidant nordihydroguairetic acid to clones of the natural-death nutant or wild-type neurospora crassa growing on 5-fluorotryptophan not only alleviates the time-dependent deterioration of growth rate (senescence), but also inhibits the accumulation of a fluorescent pigment (lipofuscin), an end-product of lipid peroxidation. in the three model system of ageing in n. crassa that we have examined, it is now clear that massive accumulation of lipofuscin begins sh ...1978149885
an apparent connection between histidine, recombination, and repair in neurospora.two mutants of neurospora crassa, uvs-3 and mei-3, share four properties--uv sensitivity, inhibition by histidine, meiotic blockage when homozygous, and increased duplication instability (due to mitotic crossing over, to deletions or to both). the present paper shows that a third nonallelic mutant, uvs-6, exhibits the same four properties.--also, the instability of duplications in the absence of any uv-sensitive mutant is increased by the presence of histidine in the growth medium.1978149694
purification and characterization of epsilon-n-trimethyllysine l-amino oxidase from neurospora crassa.epsilon-n-trimethyllysine l-amino oxidase from neurospora crassa has been purified to electrophoretic homogeneity. a 1500-fold purification was obtained by centrifugation and successive column chromatography on ion-exchange and gel filtration supports. the enzyme has an estimated molecular weight of 160 000. it transforms epsilon-n-trimethyllysine into alpha-keto, epsilon-n-trimethylhexanoic acid by oxidative deamination. kinetic studies of this new enzyme are reported and its probable physiolog ...2003149561
stability of messenger rna for nitrate reductase in neurospora crassa.a method has been developed to study the synthesis and decay of the messenger rna for nitrate reductase in neurospora crassa. glutamine prevents the synthesis of the mrna which appears to have a half-life of approximately 8.5 min.1978149559
purification and characterization of 3-dehydroshikimate dehydratase, an enzyme in the inducible quinic acid catabolic pathway of neurospora crassa.3-dehydroshikimate dehydratase catalyzes the third reaction in the inducible quinic acid catabolic pathway of neurospora crassa and is encoded in the qa-4 gene of the qa gene cluster. as part of continuing genetic and biochemical studies concerning the organization and regulation of this gene cluster, 3-dehydroshikimate dehydratase has been purified and characterized biochemically. the enzyme was purified 1650-fold using the following techniques: 1) (nh4)2so4 fractionation; 2) ion exchange chrom ...2000149131
nuclear mutations conferring oligomycin resistance in neurospora crassa.mutants of neurospora crassa have been isolated that are highly resistant to inhibition by oligomycin, an inhibitor of mitochondrial atpase activity. dixon plots (dixon, m., and webb, e.c. (1964) enzymes, 2nd ed, pp. 328-330, academic press, new york) of oligomycin inhibition curves of the parent strain and the resistant mutants are linear, indicating that oligomycin interacts at a single site within the atpase complex. the ki values obtained from the mutants vary from 150 to 900 times greater t ...1978149126
does cycloheximide-induced loss of phosphate uptake activity in neurospora crassa reflect rapid turnover?addition of cycloheximide to neurospora crassa germlings growing in liquid medium caused an exponential loss of phosphate uptake activity (half-life, ca. 2 h). no loss of activity resulted when germlings were resuspended, at the time of cycloheximide addition, in medium of a substantially lower phosphate concentration. it is concluded that the phosphate uptake systems are not subject to rapid turnover.2000149111
effect of ethylene glycol on transcription of neurospora crassa conidial genome.ethylene glycol (eg) was found not to alter dna sequences in neurospora crassa conidia, though it is believed to be mutagenic in nature. molecular hybridization revealed 20% increase in whole rna transcripts in eg-treated conidia, which indicates that while untreated conidia increase rna synthesis by 2.35fold, treated conidia are inhibited and undergo only a 1.2fold increase. thus there is an inhibition in potential rna synthesis, though some rna synthesis goes on in presence of ethylene glycol.2003149018
glycogen synthesis in the fungus neurospora enzymic activity, obtained from neurospora crassa, catalyzing the incorporation of [14c]glucose from adp-[14c]glucose into a glucan of the glycogen type, is described. the properties of the adpglucose : glycogen glucosyltransferase as compared with those of the already known udp glucose : glycogen glucosyltransferase were studied. the radioactive products obtained with udp-14c]glucose or adp-[14c]glucose released all the radioactivity as maltose after alpha or beta amylase treatment. glucose ...2002148915
purification and characterization of quinate (shikimate) dehydrogenase, an enzyme in the inducible quinic acid catabolic pathway of neurospora crassa.the bifunctional enzyme quinate (shikimate) dehydrogenase (quinate: nad+ oxidoreductase, ec, which catalyzes the first reaction in the inducible quinic acid catabolic pathway of neurospora crassa, has been purified to homogeneity. the enzyme is a monomer of 41000 daltons with an s20,w = 2.94 s. however, electrophoresis under non-denaturing conditions revealed three protein species, which have both quinate and shikimate dehydrogenase activities. the enzyme, with a single binding site fo ...1978148913
characterization of neurospora crassa polyadenylated messenger ribonucleic acid: structure of the 5'-terminus. 2003148868
molecular alteration in a neurospora crassa morphological mutant and its phenocopy.a procedure using ion exchange chromatography has been developed to detect alterations in a polysaccharide produced by neurospora crassa. the polysaccharide, isolated from medium that has supported the growth of a culture, is highly responsive to the 3-methyl-2-benzothiazolinone hydrazone assay, indicating a high hexosamine content. the substance elaborated by wild-type n. crassa can be fractionated into two components that appear by rechromatography to be closely related. when isolated from mut ...1978148650
ultrastructural study of microcyclic macroconidiation in neurospora crassa.heat-shock of macroconidia of neurospora crassa at 46 degrees c followed by shift-down to 25 degrees c determines premature conidiogenesis. the nuclei and cytoplasmof heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. in the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are later seen lining the initially simple septum separating the proconidial units into ...1978148251
small stable rna of neurospora crassa. 1978148000
cyanide- and hydroxamate-resistant respiration in neurospora crassa.strain inl-89601 of neurospora crassa respires exclusively by means of the mitochondrial cytochrome chain. the respiration of this strain is entirely inhibited by cyanide or antimycin a, the classical inhibitors of cytochrome chain respiration. when this strain was grown in the presence of chloramphenicol, however, two additional terminal oxidases were detected. one of these oxidases is inhibited by substituted hydroxamic acids and has been described previously. the second oxidase was not inhibi ...1978147864
genetic and physiological characteristics of a slow-growing circadian clock mutant of neurospora crassa.a circadian clock mutant of neurospora crassa with a period length of about 25.8 hours (4 hr longer than wild type) has been isolated after mutagenesis of the band strain. this mutant, called frq-5, segregates as a single nuclear gene, maps near the centromere on linkage group iii, and is unlinked to four previously described clock mutants clustered on linkage group vii r (feldman and hoyle 1973, 1976). frq-5 differs from the other clock mutants in at least two other respects: (1) it is recessiv ...1978147796
regulation, purification, and properties of xanthine dehydrogenase in neurospora crassa.xanthine dehydrogenase (ec is the first enzyme in the degradative pathway by which fungi convert purines to ammonia. in vivo, the activity is induced 6-fold by growth in uric acid. hypoxanthine, xanthine, adenine, or guanine also induce enzyme activity but to a lesser degree. immunoelectrophoresis using monospecific antibodies prepared against neurospora crassa xanthine dehydrogenase shows that the induced increase in enzyme activity results from increased numbers of xanthine dehydroge ...1978147274
the subunit structure of the arom multienzyme complex of neurospora crassa. evidence from peptide 'maps' for the identity of the subunits.evidence was obtained, from polyacrylamide-gel electrophoresis in the presence of urea and from peptide 'mapping' of specifically labelled cysteine-and methionine-containing peptides, that the two subunits of the arom multienzyme complex of neurospora crassa are chemically very similar and possibly identical.1978147081
structural features of normal and complemented forms of the neurospora isopropylmalate isomerase.the isopropylmalate isomerase (ec of neurospora crassa is a globular protein consisting of a single polypeptide chain with a molecular weight of about 90,000. the isomerase cannot easily be freed of a contaminating protease which cleaves the enzyme into two major fragments, one of approximately 56,000 and the other 37,000 daltons. this suggests that the folded polypeptide chain may contain some hinge point or loop exposed on the surface which makes it susceptible to proteolytic attack. ...1978146703
regulation of isopropylmalate isomerase synthesis in neurospora crassa.the capacity to synthetize isopropylmalate isomerase (ec by neurospora crassa increased during induction in the presence of cycloheximide but was inhibited by proflavine and other inhibitors of rna synthesis. turnover of the enzyme once formed appeared negligible, but the message (measured as enzyme-forming capacity) had a half-life of 4 to 8 min. a comparison of the kinetics of induction in the wild type and a newly isolated alpha-isopropylmalate-permeable strain suggested strongly th ...1978146702
induction and repression of nitrate reductase in neurospora crassa.synthesis of wild-type neurospora crassa assimilatory nitrate reductase is induced in the presence of nitrate ions and repressed in the presence of ammonium ions. effects of several neurospora mutations on the regulation of this enzyme are shown: (i) the mutants, nit-1 and nit-3, involving separate lesions, lack reduced nicotinamide adenine dinucleotide (nadph)-nitrate reductase activity and at least one of three other activities associated with the wild-type enzyme. the two mutants do not requi ...1978146700
effect of pre-treatment with 5-bromouracil in an ultraviolet sensitive strain of neurospora crassa. 1977146631
physiological response of neurospora conidia to freezing in the dehydrated, hydrated, or germinated state.this study concerned the response to freezing of neurospora crassa conidia in four different states: air-dry, hydrated in water, hydrated in vogel medium lacking only sucrose, or hydrated in complete vogel medium. all hydrated conidia were incubated in one of the above media for various times before freezing and were then washed and frozen in distilled water. viability was estimated by three techniques, and the agreement among them was good. hydration of air-dry conidia was found to be very rapi ...1978146455
molybdenum cofactors from molybdoenzymes and in vitro reconstitution of nitrogenase and nitrate reductase.a molybdenum cofactor (mo-co) from xanthine oxidase (xanthine:oxygen oxidoreductase, ec can be isolated from the enzyme by a technique that has been used to isolate an iron-molybdenum cofactor (femo-co) from component i of nitrogenase. n-methylformamide is used for the extraction of these molybdenum cofactors. mo-co from xanthine oxidase activates nitrate reductase (nadph:nitrate oxidoreductase, ec in an extract from neurospora crassa mutant strain nit-1; however, femo-co is un ...1977146198
nucleotide sequence of neurospora crassa cytoplasmic initiator trna.initiator methionine trna from the cytoplasm of neurospora crassa has been purified and sequenced. the sequence is: pagcugcaum1ggcgcagcggaagcgcm22gcy*gggcucaut6aacccggagm7gu (or d) - cacucgaucgm1aaacgag*uugcagcuaccaoh. similar to initiator trnas from the cytoplasm of other eukaryotes, this trna also contains the sequence -aucg- instead of the usual -tphicg (or a)- found in loop iv of other trnas. the sequence of the n. crassa cytoplasmic initiator trna is quite different from that of the corresp ...1977146192
mitochondrial ribosome assembly in neurospora crassa. chloramphenicol inhibits the maturation of small ribosomal subunits. 1977146091
transport of cytoplasmically synthesized proteins into the mitochondria in a cell free system from neurospora crassa.synthesis and transport of mitochondrial proteins were followed in a cell-free homogenate of neurospora crassa in which mitochondrial translation was inhibited. proteins synthesized on cytoplasmic ribosomes are transferred into the mitochondrial fraction. the relative amounts of proteins which are transferred in vitro are comparable to those transferred in whole cells. cycloheximide and puromycin inhibit the synthesis of mitochondrial proteins but not their transfer into mitochondria. the transf ...1996145943
structure and function of initiator methionine trna from the mitochondria of neurospora crassa. 1978145896
morphology of slime variants of neurospora crassa growing on a glass surface in liquid medium. 1. under normal conditions and 2. in the presence of inhibitors. 1977145837
isolation of putrescine-requiring mutants of neurospora crassa.two auxotrophs of neurospora crassa have been isolated that give a positive growth response to putrescine, spermidine or spermine. one of the mutants is deficient in ornithine decarboxylase activity and has been designated put-i. both mutants map on linkage group vr, fail to complement and are infertile when crossed to one another, indicating that they are probably alleles. a putrescine auxotroph is incapable of suppressing a pro-4 mutant. the isolation of the mutants confirms that putrescine is ...1977145823
association and dissociation of neurospora crassa cytoplasmic ribosomes.dissociation and association factors of ribosomal particles were detected in extracts from neurospora crassa at different stages of growth. the dissociation factor was easily released into the s100 supernatant fraction, whereas the association factor remained bound to the ribosomes.1978145436
purine base transport in nit-2 mutants of neurospora crassa.the nit-2 mutants possess general purine transport activity. reduced hypoxanthine uptake in germinated conidia of these mutants may be a consequence of their defective purine metabolism.2003145435
proof of de novo synthesis of the qa enzymes of neurospora crassa during neurospora crassa three inducible enzymes are necessary to catabolize quinic acid to protocatechuic acid. the three genes encoding these enzymes are tightly linked on chromosome vii near methionine-7 (me-7). this qa cluster includes a fourth gene, qa-1, which encodes a regulatory protein apparently exerting positive control over transcription of the other three qa genes. however, an alternative hypothesis is that the qa-1 protein simply activates preformed polypeptides derived from the three ...1977144915
isolation and preparation of pretyrosine, accumulated as a dead-end metabolite by neurospora crassa.pretyrosine is an amino acid intermediate of phenylalanine and/or tyrosine biosyntheses in a variety of organisms. a procedure for the isolation of high-quality pretyrosine as the barium salt is described. stable solutions of ammonium pretyrosine that are suitable for use as substrate in enzyme assays can be prepared in good yield with relatively few purification steps. a triple mutant of neurospora crassa, bearing genetic blocks corresponding to each initial enzyme step of the three pathway bra ...1977144721
germination-defective mutant of neurospora crassa that responds to siderophores.a conditionally germination-defective mutant of neurospora crassa has been found to be partially curable by ferricrocin and other siderophores. the mutant conidia rapidly lose their membrane-bound siderophores when suspended in buffer or growth media. germination is consequently delayed unless large numbers of conidia are present (positive population effect). this indicates that the mutant has a membrane defect involving the siderophore attachment site.1977144720
uptake and efflux of adenine and its derivatives in neurospora crassa.conidia of wild-type neurospora crassa, preincubated for 3 1/2 h in growth medium, showed a typical triphasic pattern of adenine uptake. the three phases consisted of a quick initial uptake, followed by a plateau phase, and then by a resume lowered uptake. a study of the relative influx and efflux of [14c] adenine showed that the plateau phase in fact is a period of transmembrane movement of adenine and adenine metabolites. the efflux during the plateau phase essentially cancelled out all the in ...1977144552
enzymatic release of iron from sideramines in fungi. nadh:sideramine oxidoreductase in neurospora crassa.young mycelia of the fungus neurospora crassa contain a soluble nadh-linked sideramine reductase, which may be responsible for liberating iron in vivo from accumulated sideramines during iron-deficient cultivation. the enzymes can be assayed using a soluble supernatant fraction, edta, and an atmosphere of pure nitrogen. the enzyme is stable without loss of activity up to 45 degrees c and has an optimum of activity at ph 7.0. besides coprogen (km = 100 micrometer, v=2.8 nmol/min per mg protein), ...1977144535
dissociation of an enzyme complex from neurospora crassa. evidence for a protease. 1977144533
Displaying items 5501 - 5600 of 5889