Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
regulation of exocellular proteases in neurospora crassa: metabolic requirements of the process.to induce exocellular proteolytic enzyme from carbon-starved exponential-phase cells of neurospora crassa, both a protein substrate and an activating protease of certain specific properties must be present at the same time. the cells must be capable of protein synthesis, since cycloheximide inhibits the process, but cell growth, as determined by increase in cell mass, does not appear to be required. both soluble (bovine serum albumin, myoglobin) and insoluble protein substrates (collagen, corn z ...1975125263
the cleavage of transfer rna by a single strang specific endonuclease from neurospora crassa.endonuclease from neurospora crassa (ncnase), an enzyme with specificity for polynucleotides lacking an ordered structure, was shown to cleave su+3 trnatyr from e. coli preferentially in the anticodon region. the enzyme cleaved unfractionated trna primarily to 30 - 50 nucleotide size fragments, implying that most or all trna species are also cleaved in the anticodon region. the 3' terminal sequence c-a was cleaved as well. the results are discussed with respect to the three dimensional structure ...1975125412
purification and properties of the fatty acids synthetase complex from neurospora crassa, and the nature of the fas-mutation.a procedure is described for the purification of the fatty acid synthetase complex (fas) from neurospora crassa. the enzyme complex has a molecular weight of 2.3 times 10(6), contains 6 mol of 4'-phosphopantetheine per mol, and on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate gives a single band, or a closely spaced doublet, which comigrates with standard myosin (molecular weight, 2 times 10(5)). since the slightly retarded component in the doublet accounts for all ...1975126228
characterization of 5.8s ribosomal ribonucleic acid in neurospora crassa.neurospora crassa ribosomes contain a species of ribonucleic acid (rna) of molecular weight 54,000, similar to 5.8s ribosomal rna previously described for other eukaryotic organisms. the 5.8s rna from n. crassa was found to be released by heat treatment at 60 c from 25s ribosomal rna but not from 18s ribosomal rna. the base composition of n. crassa 5.8s rna was similar to that of 5.8s rna from saccharomyces cerevisiae, but differed from animal 5.8s rna. during the course of this study, it was di ...1975126993
arrangement of sequences in the inverted terminal repetition of adenovirus 18 dna.in contrast to the single-stranded circular molecules produced with denatured dna from other adenoviruses, there was associated with nearly all circular molecules of adenovirus type 18 a visible, duplex projection. these projections had a mean contour length of 0.31 +/- 0.12 mum, equivalent to approximately 3% of genome length. individual projections ranged in size from 0.1 to 2 mum. alkaline sucrose gradient purification of single-stranded molecules did not affect formation of these projections ...1975127173
mutagenicity assays on fluorescent whitening agents using microorganisms.six fluorescent whitening agents (fwas) have been re-examined for their activity as inducers of cytoplasmic petite mutants and mitotic gene conversion in diploid yeast saccharomyces cerebisiae and reversion from auxotrophy to prototrophy in neurospora crassa, escherichia coli and salmonella typhimurium. the results provide no indication that the fwas examinded produce mutagenic changes or any other alterations in the gene material. in a recent re-examination with salmonella using the method of a ...1975132347
mutants of neurospora deficient in nicotinamide adenine dinucleotide (phosphate) glycohydrolase.a new screening technique has been developed for the rapid identification of neurospora crassa mutants that are deficient in nicotinamide adenine dinucleotide glycohydrolase (nadase) and nicotinamide adenine dinucleotide phosphate glycohydrolase (nadpase) activities. using this procedure, five single-gene mutants were isolated whose singular difference from wild type appeared to be the absence of nad(p)ase (ec 3.2.2.6). all five mutants were found to be genetically allelic and did not complement ...1975165174
differential rates of synthesis of glycerokinase and glycerophosphate dehydrogenase in neurospora crassa during induction. 1975165778
the regulated catabolism of endogenous and exogenous phosphatidylinositol by saccharomyces cerevisiae leading to extracellular glycerophosphorylinositol and inositol.it was previously shown that phosphatidylinositol catabolism leads to the accumulation of glycerophosphorylinositol in the culture medium of saccharomyces cerevisiae. we now find that lack of an energy source (glucose) reduces the formation of glycerophosphorylinositol and increases extra-cellular inositol. this situation is reversed by refeeding glucose. [3h]phosphatidylinositol is the precursor of extra-cellular [3h]inositol with energy-starved cells. extracellular glycerophosphorylcholine and ...1975166987
kinetics and morphology of glucose-limited cultures of moulds grown in a chemostat and on solid media.the affinity (ks value) of geotrichum candidum for glucose determined from chemostate cultures was ca. 1 mg/1. ks values for glucose was also estimated from the radial growth rates of colonies of g. candidum and neurospora crassa grown on media solidified with agar or silica gel. an assessment is made of the use of colony radial growth rate to determine substrate affinities. the length of apical and intercalary hyphal comparte ments, internode length and the diameter of leading hyphaat the margi ...1975168829
the influence of amino acid substitutions on the conformational energy of cytochrome c.conformational energies have been evaluated for each of the staggered side-chain conformations associated with the 261 amino acid substitutions known to occur among 60 eucaryotic species. at least 86% of these substitutions can be sterically accommodated (one at a time) within the structure of horse-heart cytochrome c resulting from conformational energy refinement. simultaneous incorporation of all pertinent amino acid substitutions found in eight representative species into the refined horse-h ...1975169879
the pyridine nucleosidases from bacillus subtilis and neurospora crassa. isolation and structural properties. 1975170869
[studies on the conidial differentiation of "neurospora crassa" vi.--functional anomalies of the conditional aconidial mutant "amycelial" (author's transl)].studies using the morphological mutant "amycelial"--a conditional, aconidial strain of n. crassa--have revealed certain consistent functional and biochemical differences from wild type strains showing normal morphology and conidia formation. thus it was found that the mutant strain showed an abnormal utilization of protein reserves at a time when there is extensive degradation during conidiogenesis in wild type. in addition, the mutant exhibited abnormally low oxygen consumption and free amino a ...1975173223
partial amino-acid sequence of nad-specific glutamate dehydrogenase of neurospora crassa.parts of the primary structure of the nad-specific glutamate dehydrogenase [l-glutamate:nad oxidoreductase (deaminating), ec 1.4.1.2] from neurospora crassa are presented. segments of the sequence representing 886 unique amino-acid residues have been determined; the largest contains 267 residues. there are only short regions of possible homology between this enzyme and the glutamate dehydrogenases of bovine liver or the nadp-specific enzyme of neurospora. the large size of the subunit (116,000 m ...1975174080
characterization of dna condensates induced by poly(ethylene oxide) and polylysine.high-molecular-weight dna is known to collapse into very compact particles in a salt solution containing polymers like poly(ethylene oxide) [(eo)n] or polyacrylate. the biological relevance of this phenomenon is suggested by our recent finding that high concentrations of the highly acidic internal peptides found in the mature t4 bacteriophage head, as well as poly(glutamic acid) and poly(aspartic acid), can collapse dna in a similar manner. the structure of dnas collapsed by various methods has ...19751060108
kinetic studies on the specificity of chelate-iron uptake in aspergillus.three strains of the fungus aspergillus, aspergillus quadricinctus (e. yuill), a. fumigatus (fresenius), and a. melleus (yukawa), each producing different iron-chelating compounds during iron-deficient cultivation, were used for 55fe3+ uptake measurements. iron from chelates of the ferrichrome-type family was taken up by young mycelia of all strains tested, irrespective of the ferrichrome-type compound these strains predominantly produce in low-iron cultures. ferrichrysin-producing strains, howe ...19751099079
genetic control of radiation sensitivity and dna repair in neurospora.radiation sensitivity in the fungus neurospora crassa is under the control of at least eight distinct loci and is also affected by cytoplasmic factors. although radiation-sensitive mutants which affect inter- or intragenic meiotic recombination have not been isolated, mutants which are defective in the repair of pyrimidine dimers have been found. evidence from both mutational and biochemical studies shows that neurospora has an excision-repair system for pyrimidine dimers which is very similar t ...19751103873
hydroxykynureninase and the excretion of 3-hydroxyanthranilate by yeast.a comparative analysis of the kynureninase-type activity found in various organisms has demonstrated two forms of enzyme. one, inducible by tryptophan, has a relatively low km for l-kynurenine, and is found in microorganisms such as pseudomonas fluorescens and neurospora crassa. the other, unaffected by tryptophan, has a low km for l-3-hydroxykynurenine and is found in a wide variety of organisms, including molds, amphibia, birds and mammals. the yeast saccharomyces cerevisiae lacks the inducibl ...19751244118
regulation of the activity of microbial kynureninase by transamination of the enzyme-bound coenzyme.kynureninase was purified to homogeneity from the extracts of pseudomonas marginalis and neurospora crassa. the active kynureninase containing pyridoxal 5'-phosphate transaminates with l-ornithine or l-alanine to form the inactive pyridoxamine 5'-phosphate form of enzyme and delta1-pyrroline-2-carboxylate or pyruvate. this inactive enzyme transaminates with pyruvate to restore the active pyridoxal 5'-phosphate enzyme and l-alanine. the activity of kynureninase is regulated in this manner by tran ...19751244119
nicotinamide 3,n4-ethenocytosine dinucleotide, an analog of nicotinamide adenine dinucleotide. synthesis and enzyme studies.a structural analog of nad+, nicotinamide 3,n-4ethenocytosine dinucleotide (epsilonncd+), has been synthesized, characterized, and compared in activity with the natural coenzyme in several enzyme systems. the vmax and apparent km values were determined for nad+, epsilonncd+, and epsilonnad+ (nicotinamide 1, n6-ethenoadenine dinucleotide) with yeast alcohol, horse liver alcohol, pig heart malate, beef liver glutamate, and rabbit muscle lactate and glyceraldehyde-3-phosphate dehydrogenases. the vm ...1975234741
hyphal wall growth in neurospora crassa and geotrichum candidum.growth of the walls of hyphae of neurospora crassa and geotrichum candidum was studied using longitudinal and serial transverse sectioning methods. rigidification of the hyphal wall below the extension zone did not appear to involve the gross formation of a secondary wall since the transition from extensible to non-extensible wall was not associated with an increase in thickness. however, behind the extension zone the walls leading hyphae of n. crassa increased in thickness until eventually they ...1975128612
identification of the ubiquinone-binding site of nadh:ubiquinone oxidoreductase (complex i) from neurospora crassa.in order to localize the ubiquinone-binding site of complex i (nadh:ubiquinone oxidoreductase), a novel photoreactive ubiquinone analogue (q0c7arn3) has been synthesized. it is shown that the direct chemical precursor of this analogue (q0c7arno2) and the analogue itself are accepted as substrates in an enzyme assay utilizing ubiquinone-depleted mitochondrial membranes of neurospora crassa. the activity of the enzyme applying these derivatives is inhibited by 50% at a concentration of 9 and 20 mi ...19751445878
physical map of circular mitochondrial dna from neurospora crassa. 1975132366
a high molecular weight dihydro-orotate dehydrogenase of neurospora crassa. purification and properties of the enzyme.some of the unusual molecular and catalytic properties of a high molecular weight dihydro-orotate dehydrogenase (dhod) from neurospora crassa have been determined. comparison of the properties of this enzyme with the properties of the soluble biosynthetic enzyme of prokaryotes has revealed several important differences. the fungal enzyme is located in a mitochondrial membrane in a position consistent with linkage with the respiratory chain through ubiquinone (miller, r. w.: arch. biochem, biophy ...1975130199
morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of neurospora crassa.a comparison was made of the morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of neurospora crassa. undifferentiated mycelia were formed during exponential growth on solid media or submerged culture. hyphae at the margin of differentiated mycelia (colonies) differed from undifferentiated mycelia in diameter, extension rate, extension zone length, and intercalary and apical compartment length. the mean hyphal extension rate (e) of an undifferentiated myceliu ...1975128613
rapid loss of a novel phenylalanyl-trna on germination of neurospora crassa conidia. 1975127124
mutagenic evaluation of antischistosomal drugs and their derivatives in neurospora crassa.the mutagenic activities of lucanthone, hycanthone, niridazole, and the indazole analogs of lucanthone (ia-3 and ia-5) or hycanthone (ia-4 and ia-6) were studied by assaying for the induction of specific locus mutations in the ad-3 region of n. crassa. the results show that lucanthone, hycanthone, and their indazole analogs (ia-3 through ia-6) are all mutagenic in n. crassa when conidia are treated with any of these compounds. on a per mole basis, hycanthone is the least toxic and mutagenic, whe ...1975128637
adaptive significance of vegetative incompatibility in neurospora crassa.certain features reminiscent of sexuality occur in the vegetative life cycle of some filamentous fungi such as neurospora crassa. hyphal fusions can occur between genetically different individuals, thereby endowing the new composite mycelium, a heterokaryon, with some of the advantages of heterozygosity usually associated with diploid organisms. in n. crassa, however, there are a number of incompatibility loci which prevent formation of heterokaryons unless the alleles at the incompatibility loc ...1975128487
neurospora crassa conidial germination: role of endogenous amino acid pools.the levels of the endogenous amino acid pools in conidia, germinating conidia, and mycelia of wild-type neurospora crassa were measured. three different chromatographic procedures employing the amino acid analyzer were used to identify and quantitatively measure 28 different ninhydrin-positive compounds. all of the common amino acids were detected in conidial extracts except proline, methionine, and cystine. the levels of these three amino acid pools were also very low in mycelia. during the fir ...1975170245
isolation and characterization of a mitochondrially synthesized polypeptide from neurospora crassa cni-1 mutant.a polypeptide with a molecular weight of 8 500 (hp 8 500) was isolated from the mitochondrial membrane of the nuclear mutant cni-1 of neurospora crassa. this mutant is characterized by a cyanide-insensitive respiration and by a deficiency in the cytochromes aa3 and b. the polypeptide is synthesized on mitochondrial ribosomes. it has an extremely hydrophobic character; it is insoluble in aqueous media in the absence of sodium dodecylsulfate and is soluble in acid chloroform/methanol. it lacks his ...1975129427
effect of histidine on purine nucleotide synthesis and utilization in neurospora crassa.histidine affects de novo purine nucleotide synthesis and purine nucleotide pool utilization in neurospora crassa. the former effect was assessed qualitatively by the presence or absence of purple pigment production in ad3b and ad3a mutants. tryptophan also affected the de novo purine nucleotide synthesis. the effect of histidine on purine nucleotide pool utilization resulted in stimulated germination of ad8 and ad4 mutant conidia in adenine-deficient medium. increased germination was correlated ...1975126229
characteristics of a glycerol utilization mutant of neurospora crassa.a mutant of neurospora crassa able to grow on liquid minimal glycerol medium without evidence of conidiation and with high cell yields has been isolated and shown to be allelic to ff-1. the glycerol-specific induction of glycerokinase and glycerol-3-phosphate dehydrogenase was similar in both wild-type and mutant cells, although higher specific activities as well as higher glycerokinase cross-reacting material levels were found in fully induced mutant cells. after growth in minimal glycerol medi ...1975126227
effect of mutations in the qa gene cluster of neurospora crassa on the enzyme catabolic dehydroquinase.catabolic dehydroquinase, which functions in the inducible quinic acid catabolic pathway of neurospora crassa, has been purified from wild type (74-a) and three mutants in the qa gene cluster. the mutant strains were: 105c, a temperature-sensitive constitutive mutant in the qa-1 regulatory locus; m-16, a qa-3 mutant deficient in quinate dehydrogenase activity; and 237, a leaky qa-2 mutant which possess very low levels of catabolic dehydroquinase activity. the enzymes purified from strains 74-a, ...1975126226
purine base transport in neurospora crassa.observations presented in this paper point to the presence of dual transport mechanisms for the base adenine in neurospora crassa. competition for transport, as well as growth inhibition studies using an ad-1 auxotroph, show that the purine bases adenine, guanine, and hypoxanthine share at least one transport mechanism which is insensitive to adenosine, cytosine, and a variety of other purine base analogues. on the other hand, uptake of adenine by an ad-8 mutant strain unable to transport [8-14c ...1975126225
glycerophospholipid variation in choline and inositol auxotrophs of neurospora crassa. internal compensation among zwitterionic and anionic species.the glycerophospholipids of cultures of neurospora crassa were extracted, deacylated, and analyzed. in addition to a wild-type strain, several auxotrophic mutant strains were examined: chol-1 (defective s-adenosylmethionine: phosphatidylethanolamine methyltransferase), chol-2 (defective s-adenosyl methionine:phosphatidylmonomethylethanolamine (dimethylethanolamine) methyltransferase), and inos (defective myoinositol-1-phosphate phosphatase). in addition, a double mutant strain, chol-1;chol-2, wa ...1975126231
regulation of mitochondrial biogenesis in neurospora crassa. 1975134474
escape from mating-type incompatibility in bisexual (a + a) neurospora heterokaryons.in neurospora crassa, strains of opposite mating type generally do not form stable heterokaryons because the mating type locus acts as a heterokaryon incompatibility locus. however, when one a and one a strain, having complementing auxotrophic mutants, are placed together on minimal medium, growth may occur, although the growth is generally slow. in this study, escape from such slow growth to that at a wild type or near-wild type rate was observed. the escape cultures are stable heterokaryons, m ...1975128407
influence of light on the inhibition of neurospora crassa growth by the antibiotic edeine. 1975127125
the amino acid sequence of neurospora nadp-specific glutamate dehydrogenase. peptic and chymotryptic peptides and the complete sequence.peptic and chymotryptic peptides were isolated form the nadp-specific glutamate dehydrogenase of neurospora crassa and substantially sequenced. out of 452 residues in the polypeptide chain, 265 were recovered in the peptic and 427 in the chymotryptic peptides. together with the tryptic peptides [wootton, j. c., taylor, j. g., jackson, a. a., chambers, g. k. & fincham, j. r. s. (1975) biochem. j. 149, 749-755], these establish the complete sequence of the chain, including the acid and amide assig ...19751002
the amino acid sequence of neurospora nadp-specific glutamate dehydrogenase. the tryptic peptides.the nadp-specific glutamate dehydrogenase of neurospora crassa was digested with trypsin, and peptides accounting for 441 out of the 452 residues of the polypeptide chain were isolated and substantially sequenced. additional experimental detail has been deposited as supplementary publication sup 50052 (11 pages) with the british library (lending division), boston spa, wetherby, w. yorkshire ls23 7bq, u.k., from whom copies may be obtained under the terms given in biochem j. (1975) 145, 5.19751000
oscillations of an electrogenic pump in the plasma membrane of neurospora.the presence of the poky mutation in neurospora crassa produces mitochondria which are defective in cytochromes b and aa3 but which compensate by means of an alternate, cyanide-insensitive oxidase. as previously reported (slayman, rees, orchard & slayman, j. biol. chem., 250:396, 1975) cyanide blockade of the poky strain carrying the partial suppressor f results in a metabolic downshift of only 56%, compared with a downshift of 98% in wild-type neurospora; the downshift is accompanied by exponen ...1975126326
neurospora crassa invertase. a study of amino acids at the active center.1. the effects on neurospora crassa invertase (beta-d-fructofuranoside fructohydrolase, ec 3.2.1.26) of a variety of group specific reagnets and other potential inhibitors were determined during a search for an irreversible inhibitor of the enzyme. aniline, pyridoxal, enzyme substrate and products did not inactivate invertase under reducing conditions. bromoacetic acid, iodoacetic acid, iodoacetamide, p-chloromercuribenzoate, hydroxylamine and 2-hydroxy-5-nitrobenzyl bromide were also ineffectiv ...1975239750
denaturation map of the circular mitochondrial genome of neurospora crassa.a denaturation map of mitochondrial dna from the wild type strain 5256 of neurospora crassa was constructed by computer analysis of the contour length distribution of single- and double-stranded regions of nineteen circular and three full length linear molecules after partial denaturation. the data suggest that mitochondrial dna in this strain is a homogeneous population of a circular molecule of molecular weight 41 - 10(6) with an asymmetric distribution of at-rich regions, and that linear mole ...1975126085
regulation of mitochondrial membrane assembly in neurospora crassa. transient expression of a respiratory mutant phenotype.cultures of mutant cni-1, a chromosomal mutant of neurospora crassa, undergo a marked change in respiratory properties as the age of the culture increases. early log phase cultures have a high level of respiration that is insensitive to inhibition by cyanide or antimycin a. late log and stationary phase cultures have reduced rates of respiration. a high percentage of this respiration is inhibited by cyanide. mitochondria from early log phase cni-1 have an excess of cytochrome c and little or no ...1975168205
purification and characterization of catabolic dehydroquinase, an enzyme in the inducible quinic acid catabolic pathway of neurospora crassa.catabolic dehydroquinase which functions in the inducible quinic acid catabolic pathway in neurospora crassa has been purified 8000-fold. the enzyme was purified by two methods. one used heat denaturation of contaminating proteins; the other used antibody affinity chromatography. the preparations obtained by these two methods were identical by all criteria. the purified enzyme is extremely resistant to thermal denaturation as well as denaturation 0y urea and guanidine hydrochloride at 25 degrees ...1975125280
genetic and metabolic control of the purine catabolic enzymes of neurospora crasse.neurospora crassa can utilize various purine bases such as xanthine or uric acid and their catabolic products as a nitrogen source. four classes of mutants which affect the purine degradative pathway were isolated and studied. mutants of the aln-1 class specifically lack allantoinase, while alc-1 mutants lack allantoicase. mutants designated as xdh-1 cannot utilize hypoxanthine as a nitrogen source and are presumed to be deficient in xanthine dehydrogenase activity. a regulatory mutant, amr, was ...1975126363
proteolytic enzymes of neurospora crassa. purification and some properties of five intracellular proteinases.five intracellular proteolytic enzymes from neurospora crassa were isolated and partially characterized: an acidic and an alkaline endopeptidase, one carboxypeptidase and two aminopeptidases. all these proteinases were purified from the same crude extract to homogenity by heat treatment, precipitation with ammonium sulfate, chromatography on deae-cellulose, cm-cellulose, deae-sephadex, hydroxyapatite and by gel filtration. the acid proteinase hydrolysed acid-denatured haemoglobin at ph 3.0. the ...1975240706
regulation of two extracellular proteases of neurospora crassa by induction and by carbon-nitrogen and sulfur-metabolite repression. 1975240316
effect of ph and biotin on a circadian rhyythm of conidiation in neurospora crassa.expression of a circadian rhythm of conidiation in neurospora crassa is enhanced in cultures grown on medium that is neutral or deficient in biotin.1975237880
two forms of a mitochondrial endonuclease in neurospora crassa.mitochondrial nuclease activity in neurospora crassa occurs in membrane-bound and soluble forms in approximately equal proportions. these activities apparently are due to the same enzyme, which has an approximate molecular weight of 120 000. a portion of the insoluble enzyme appears to be associated with the inner mitochondrial membrane and is resistant to solubilization by detergent treatment as well as by physical disruption methods.1975168950
levels and rates of synthesis of ribosomal ribonucleic acid, transfer ribonucleic acid, and protein in neurospora crassa in different steady states of growth.the levels of ribosomes, trna molecules, and total protein per genome in neurospora mycelia have been determined in eight different conditions of exponential growth. by increasing the rate of growth the number of ribosomes per genome increases dramatically while the level of total protein remains almost unchanged and the level of trna increases only slightly. the rates of synthesis of each of the macromolecules have been estimated. increasing the rate of growth (mu) up to 0.5, the ratio between ...1975124730
laminarinases of neurospora crassa : part ii. isolation, purification and characterization. 1975130339
lipophilic proteins encoded by mitochondrial and nuclear genes in neurospora crassa.mitochondrial proteins soluble in neutral chloroform-methanol (2:1) were separated from lipids by ether precipitation and resolved by sephadex g-200 filtration in the presence of dodecylsulfate into two major fractions eluting in the excluded region (peak i) and in a region of an apparent molecular weight 8000 (peak ii). residual phospholipids are found only in peak ii. peak i consists of several aggregated small polypeptides of molecular weights around 8000, which can be disaggregated by mild o ...1975126152
size restriction on utilization of peptides by amino acid auxotrophs of neurospora crassa.growth of an amino acid auxotroph of neurospora crassa on oligopeptides is shown to occur by extracellular hydrolysis, with subsequent utilization of monomer amino acid residues, and by transport of peptides. peptides with a hydrodynamic volume greater than that of trileucine are not transported, and this lack of transport is shown to be due to restriction by the oligopeptide transport system rather than the cell wall.1975125269
changes in glucosamine and galactosamine levels during conidial germination in neurospora crassa.the levels of glucosamine and galactosamine were determined in conidia, germinating conidia, and vegetative mycelia of neurospora crassa. in the vegetative mycelia about 90% of the amino sugars were shown to be components of the cell wall. the remaining 10% of the amino sugars were tentatively identified as the nucleotide sugars uridine diphospho-2-acetamido-2-deoxy-d-glucose and uridine diphospho-2-acetamido-2-deoxy-d-galactose. conidia and vegetative mycelia contained about the same levels of ...1975125259
the essentiality of sulfhydryl groups to transport in neurospora crassa. 1975124553
microsomal activation of dimethylnitrosamine to metabolites mutagenic in neurospora crassa. 1975124014
specific fragmentation of mitochondrial dna from neurospora crassa by restriction endonuclease eco r i. 1975125087
the catecholase activity of neurospora tyrosinase.a highly purified preparation of tyrosinase from neurospora crassa was isolated with a view to elucidating its mechanism of action. both the resting and functioning molecular weights of the enzyme were determined as 33000 plus or minus 2000 and kinetic data in conjunction with binding studies indicated the presence of only one site within the enzyme for binding phenolic substrates. kinetic constants for several 0-diphenols and for the inhibitors cyanide and benzoic acid were determined and the k ...1975807476
identification of two products of mitochondrial protein synthesis associated with mitochondrial adenosine triphosphatase from neurospora crassa.soluble mitochondrial atpase (f1) isolated from neurospora crassa is resolved by dodecylsulfate-gel electrophoresis into five polypeptide bands with apparent molecular weights of 59000, 55000, 36000, 15000 and 12000. at least nine further polypeptides remain associated with atpase after disintegration of mitochondria with triton x-100 as shown by the analysis of an immunoprecipitate obtained with antiserum to f1 atpase. two of the associated polypeptides with apparent molecular weights of 19000 ...1975125201
regulation of methionine biosythesis in neurospora crassa. 1975124550
gamma-ray inactivation of conidia from heterokaryons of neurospora crassa containing uv-sensitive mutations.two-component heterokaryons were formed with the fungus neurospora crassa. the uv-sensitive mutations upr-i, uvs-4, and uvs-6 were utilized. conidia produced by these heterokaryons were exposed to gamma-rays and survival curves were established for the three conidial fractions produced by each heterokaryon. results showed that upr-i, when included in only one nuclear component, did not affect the sensitivity of any conidial fraction; however, when included in both components, all three conidial ...1975124401
heterokaryon incompatibility genes in neurospora crassa detected using duplication-producing chromosome rearrangements.evidence is presented for five or six previously undetected heterokaryon incompatibility (het) loci, bringing to about ten the number of such genes known in neurospora crassa. the genes were detected using chromosome duplications (partial diploids), on the basis of properties previously known for het genes in duplications. duplications homozygous for het genes are usually normal in growth and morphology, whereas those heterozygous are strikingly different. the heterozygotes are inhibited in thei ...1975124287
influence of n2 or o2 on two alkylating agents in neurospora crassa.previous studies have indicated that the alkylating agent, 2-methoxy-6-chloro-9-(3-[ethyl-2-chloroethyl]aminopropylamino)acridine dihydrochloride (icr-170), induces much more killing and mutation in conidia of neurospora crassa treated in an atmosphere of n2 than in an atmosphere of o2. it was desirable to determine if a similar effect--more killing and mutation in n2 than in o2--could be observed with two other known alkylating agents, beta-propiolactone (bpl) and ethyl methanesulfonate (ems), ...197549017
the subunit structure of tryptophan synthase from neurospora crassa.tryptophan synthase of neurospora crassa was purified to electrophoretic homogeneity from the wild type strain 74a which had been derepressed by the presence of 0.5 mm indoleacrylic acid in the growth medium. the isolated material migrated as a single symmetrical peak in the ultracentrifuge with a sedimentation constant of 6.0 s. gel filtration on sephadex g-200 and conventional sedimentation equilibirium yielded molecular weight estimates of 151,000 plus and minus 10,000 and 149,000 plus and mi ...1975123527
the regulation of myo-inositol-1-phosphate-synthase activity from neurospora crassa by pyrophosphate and some cations.the effect of several cations on the inhibition by ppi of the enzyme myo-inositol-1-phosphate synthase (1l-myo-inositol-1-phosphate lyase (isomerizing) ec 5.5.1.4) from neurospora crassa was studied. the study wastol biosynthesis can occur in the presence of an intracellular ppi concentration which exceeds the ki for the enzyme by 350-fold. the inhibition of enzyme activity by ppi,at ph 7.7, was reversed, in decreasing order of effectiveness, by mn-2, fe-31975236002
endogenous purine metabolism in the conidia of wild type and certain adenine mutants of neurospora crassa. i. the nature of the reserve pools and pool utilization during adenine starvation.conidia of four adenine auxotrophs (ad 9, ad 3b, ad 8 and ad 4) of neurospora crassa differ in their ability to germinate on adenine-deficient medium. a large percentage of the ad 9 and ad 3b mutant conidia germinate while those of ad 8 and ad 4 mutant do not. no correlation was found between the size of the conidial purine reserves and the conidial ability to germinate. in all the strains the major fraction of the conidial purine reserve pools was inosine. the ad 8 and ad 4 mutants are blocked ...1975236005
[isolation of a new keto-acid, produced from epsilon-n-trimethyllysine by neurospora crassa].a new epsilon-n-trimethyllysine metabolite has been isolated from the mycelium of neurospora crassa. the labelled compound produced from incubations in vivo and in vitro from epsilon-n-trimethyl ([14-c]h3)l-lysine has been identified as 2-keto-epsilon-n-trimethyl-hexanoic acid by reducing its 2,4-dinitrophenyl hydrazone back to epsilon-n-trimethyllysine by hydrogenolysis in a parr bomb. analyses on tlc and in four different ion exchange chromatographic systems show the appearance of a ninhydrin ...1975124260
characterization of neurospora crassa mutants deficient in glucosephosphate isomerase.two independent mutants of neurospora crassa lacking glucosphosphate isomerase activity (gpi) were isolated. these mutants were obtained as double mutants containing the pp or t9 mutation in addition to the gpi mutation located on linkage group iv; the pp mutation caused the inability to form protoperithecium and the loss of ascospore germination, and the t9 mutation caused the alteration in glucoamylase and several growth characteristics. the gpi mutants did not grow on fructose but grew on glu ...1975123525
effects of ribonuclease a on amino acid transport in neurospora crassa.incubation of neurospora crassa conidia with ribonuclease (rnase) a reduces transport of l-phenylalanine by those cells. under similar conditions, oxidized rnase a, rnase t1, and rnase t2 do not have this effect. incubation of conidia with active rnase covalently attached to polyacrylamide beads reduces l-phenylalanine transport. this indicates that the site of enzymatic action is at the cell surface. at the lower concentration of enzyme used in this study, incubation with rnase a reduces transp ...1975123524
intracellular localization and properties of glycerokinase and glycerophosphate dehydrogenase in neurospora crassa. 1975236729
azaguanine-resistant mutants induced by several mutagens in a neurospora heterokaryon.this paper reports the development of a new system for the detection of forward mutations in a heterokaryon of neurospora crassa. this system, designed to detect a wide variety of genetic alterations, is based upon the detection of 8-azaguanine-resistant mutants in an adenine-requiring heterokaryon carrying the aza-3 gene. induction of mutations in the aza-3 gene was detected after treatment of conidia with ultraviolet light, x-rays, ethyl methanesulfonate (ems), or the acridine mustard, icr-170 ...1975163959
glucose transport-deficient mutant of neurospora crassa with an unusual rhythmic growth pattern.a new mutant of neurospora crassa has been isolated from the patch strain. the phenotype of the new mutant includes the periodic production of sparse and dense aerial hyphae and the inability to utilize carbohydrates. the biochemical lesion was identified as a deficiency in the low-affinity glucose transport system. the high-affinity transport system appeared normal. external conditions such as medium composition, temperature change, and light-dark cycles affected the rhythm of hyphal production ...1975123245
studies on the in vitro inactivation of the neurospora crassa assimilatory nitrite reductase in the presence of reduced pyridine nucleotides plus flavin.in vitro inactivation of neurospora crassa nitrite reductase (nad(p)h: nitrite oxidoreductase, ec 1.6.6.4) can be obtained by preincubation of the enzyme with reduced pyridine nucleotide plus fad. the presence of nitrite or hydroxylamine, electron acceptors for the n. crassa nitrite reductase, or cyanide, sulfite or arsenite, competitive inhibitors with respect to nitrite of this enzyme, protects the enzyme against this inactivation. anaerobic experiments reveal that oxygen is required in order ...1975235301
isolation and characterization of neurospora crassa plasma membranes.the isolation and characterization of plasma membranes from a cell wall-less mutant of neurospora crassa are described. the plasma membranes are stabilized against fragmentation and vesiculation by treatment of intact cells with concanavalin a just prior to lysis. after lysis, the concanavalin a-stabilized plasma membrane ghosts are isolated by low speed centrifugation techniques and the purified ghosts subsequently converted to vesicles by removal of the bulk of the concanavalin a. the yield of ...1975122976
photoreceptor pigment for blue light in neurospora crassa.irradiating the mycelium of neurospora crassa with moderate intensities of blue light causes a reversible photoreduction of a b-type cytochrome. the action spectrum for the photoreduction of cytochrome b is very similar to the absorption spectrum of flavin pigments. prolonged irradiation of the mycelium with strong blue light irreversibly bleaches flavin-like pigments and as these pigments are bleached the photoresponse of cytochrome b is lost. we conclude from these and other data that a flavin ...197516659094
circadian rhythms in neurospora crassa: oscillation in the level of an adenine nucleotide.in a mutant strain (bd) of neurospora, the biological clock is visibly expressed at the growing front of a mycelial mat by sequential periods of conidiating (spore-forming) and non-conidiating growth. the edges (8 mm) of the mycelium at different ages were sampled during a 31 h period, and the adenine nucleotide levels were enzymatically assayed. in the edge region, the total adenosine 5'-monophosphate (amp) level showed an oscillation, with a minimum of 0.5 mumol/g (residual dry weight) and a m ...1975163225
regulation of the purine catabolic enzymes in neurospora crassa. 1975123428
metabolism of pyrimidine deoxyribonucleosides in neurospora crassa.the experiments in this report involve the following series of reactions which were previously demonstrated with purified enzyme preparations from neurospora crassa: thymidine a yields thymine ribonucleoside b yields thymine c yields 5-hydroxymethyluracil d yields 5-formyluracil e yields uracil-5-carboxylic acid f yields uracil. the evidence for some of the reactions occurring in vivo has been incomplete and for others totally lacking. in this paper intact cells of neurospora are shown to be cap ...1975122971
generation of adenosine triphosphate in cytochrome-deficient mutants of neurospora.the fungus neurospora crassa is known to possess a branched respiratory system consisting of the standard cytochrome chain and a cyanide-insensitive alternate oxidase. in the present experiments, the physiological function of the alternate oxidase has been analyzed by taking advantage of a number of cytochrome-deficient mutants, particularly poky f. respiration, cellular atp levels, and growth have been examined under the influence of three classes of inhibitors: inhibitors of the cytochrome cha ...1975122972
influence of edeine on intergenic and interallelic recombination in neurospora crassa.the effect of edeine and the mutation edr-2 to edeine resistance on genetic recombination in neurospora crassa was investigated. for this purpose crosses between pairs of edeine sensitive and edeine resistant strains respectively were set up without or in the presence of the drug (0-750 microg/ml). the genetic markers ylo-1, ad-1, pan-2 (b3 and b5) and tryp-2, all on linkage group vi, were used for scoring recombinants. these were ad+, tryp+ (intergenic recombination) and pan+ (interallelic reco ...197516094998
transcription of repetitive dna in neurospora crassa.repeated dna sequences of neurospora crassa were isolated and characterized. approximately 10-12% of n. crassa dna sequence were repeated, of which 7.3% were found to be transcribed in mid-log phase of mycelial growth as measured by dna:rna hybridization. it is suggested that part of repetitive dna transcripts in n. crassa were mitochondrial and part were nuclear dna. most of the nuclear repeated dnas, however, code for rrna and trna in n. crassa.197516094973
temperature-sensitive, osmotic-remedial mutants of neurospora crassa: osmotic pressure induced alterations of enzyme stability.three temperature-sensitive, adenine-requiring mutants of neurospora crassa were found to be osmotic-remedial when non-penetrating solutes were used to increase the osmolarity of the growth medium. the affected enzyme (adenylosuccinase) from one of the mutants (ad-4, 44206t) was found to have higher levels of activity when the organism was grown at non-permissive temperatures under osmotic-remedial conditions than when it was grown with adenine as a nutritional supplement. the enzyme synthesized ...197516094964
properties of the glycoprotein laccase immobilized by two methods.laccase (p-diphenol:oxygen oxidoreductase; ec 1.10.3.2) from neurospora crassa has been immobilized by two different procedures: (1) covalent attachment to sepharose 4b activated with cyanogen bromide, and (2) adsorption to concanavalin a-sepharose via the carbohydrate moiety. except for small changes in the michaelis-menten constants, no differences were noted in the enzymological properties of the immobilized enzymes when compared to free enzyme. the carbohydrate moiety of laccase involved in ...1975242172
regulation of glycolysis in neurospora crassa. kinetic properties of pyruvate kinase.pyruvate kinase (atp:pyruvate phosphotransferase, ec 2.7.1.40), extracted from the mycelium of neurospora crassa has been purified 560-fold by precipitation with ammonium sulphate, chromatography with deae-sephadex, and gel filtration with sephadex g-200. potassium and magnesium are required for enzyme activity. fructose, 1,6-diphosphate is the only physiological activator found for the enzyme. in decreasing order of potency, citrate, oxalacetate, calcium, and atp are inhibitors. phosphoenolpyru ...1975241893
beta-galactosidases from neurospora crassa. 1975237204
solubilization of valine-sensitive acetohydroxy acid synthetase from neurospora mitochondria.acetohydroxy acid synthetase [ec 4.1.3.18] of neurospora crassa has been solubilized from a mitochondrial pellet fraction by sonic treatment in 1.0 m potassium phosphate buffer at ph 7.5 containing 10 mm mgso4 and centrifugation at 180,000 x g for 20 min. the soluble enzyme thus obtained has a high specific activity and a high sensitivity to valine comparable to the original mitochondrial pellet suspension when the activity was determined in high concentrations of potassium phosphate.1975237000
glucose-6-phosphate dehydrogenase from neurospora crassa. 1975236436
sex-hormones in neurospora crassa. renewed evidence for their specificity (to "male sterility" of the a mating type). 1975127489
freeze-etch and thin section studies of neurospora crassa ascospores. 1975126461
changes in the glutathione thiol-disulfide status of neurospora crassa conidia during germination and aging.improved methods were developed for the determination of reduced glutathione (gsh), glutathione disulfide (gssg), and protein-glutathione disulfide (pssg) and applied to determine the glutathione status at various stages of the asexual life cycle for the band strain of neurospora crassa. the gsh-gssg ratio in freshly harvested dry conidia was found to be about 150 but decreased to around 6 when dryconidia were aged (stored) for 10 days after harvest. when conidia were germinated, this ratio incr ...1975123243
effects of antibiotics on the life cycle of neurospora crassa.some antibiotics and synthetic inhibitors affect, in several ways, the life cycle of neurospora crassa (germination of conidia leads to myceliar growth leads to formation of conidia). bikaverin, cyanein, scopathricin and phenethyl alcohol retard the germination of conidia, without inhibiting it completely. 5-fluorouracil, ramihyphin a and zygosporin a (cytochalasin d) do not inhibit the germination. bikaverin brings about a thickening of the hyphae of growing mycelium. ramihyphin a, cyanein, sco ...197551812
the neurospora plasma membrane atpase is an electrogenic pump.biochemicalical evidence is presented which demonstrates that the neurospora crassa plasma membrane atpase (atp phosphohydrolase, ec 3.6.1.3) is an electrogenic pump. the electrical potential across the neurospora plasma membrane, as monitored by [14c]scn- uptake by isolated neurospora plasma membrane vesicles, is markedly increased interior positive under conditions of atp hydrolysis catalyzed by plasma membrane atpase. [14c]scn- uptake by the vesicles is minimal in the presence of tris phospha ...1976131943
selection of extranuclear mutants of neurospora crassa.a procedure is described that produce primarily extranuclear mutants, of neurospora carassa. an analysis of five mutants. [cni-3], [rsp-2], [rsp-3], e1rsp-4], is presented. all five mutants segregate in an extranuclear manner. they can be assorted into two classes based on their respiratory properties: (1) those with cyanide-insensitive respiration (cni); (2) those with slow respiration (rsp). all of the mutants are female sterile. the respiratory trait can be placed in different nuclear backgro ...1976131734
developmental regulation of nicotinamide adenine dinucleotide (phosphate) glycohydrolase in neurospora crassa. 1976131723
regulation of rna synthesis in neurospora crassa. an analysis of a shift-up. 1976131689
biochemical and genetic studies on galactosamine metabolism in neurospora crassa.in neurospora, galactosamine can be released from the cell wall and from an alcohol-soluble compound by acid hydrolysis. all of the detectable alcohol-soluble galactosamine was present as uridine diphospho-2-acetamido-2-deoxy-d-galactose (udpgalnac). the results of pulse-labeling studies and enzymatic assays indicated that udpgalnac was synthesized via the epimerization of uridine diphospho-2-acetamido-2-de+xy-d-glucose (udpglcnac). a single-gene morphological mutant, doily (do), which grew at l ...1976131123
effect of ammonium ions on the induction of nitrite reductase in neurospora crassa.results with strain am-la, a glutamate dehydrogenaseless mutant, showed that ammonium ions must first be metabolized in order to repress nitrite reductase in neurospora.1976131122
modification of the regulatory properties of pyruvate kinase of neurospora by growth at elevated temperatures.pyruvate kinase (ec 2.7.1.40) was isolated from neurospora crassa mycelium grown at 28 degrees c (pk-28) and at 42 degrees c (pk-42). the regulatory properties, particularly the response towards the allosteric effector fructose 1,6-diphosphate (fdp), was different in the two enzymes. pk-28 showed an activation by fdp but pk-42, under comparable conditions, appeared to be activated by low concentrations of fdp and inhibited by higher ones. for pk-28, complex formation with fdp results in a loweri ...19766132
"action potentials" in neurospora crassa, a mycelial fungus.occasional spontaneous "action potentials" are found in mature hyphae of the fungus neurospora crassa. they can arise either from low-level sinusoidal oscillations of the membrane potential or from a linear slow depolarization which accelerates into a rapid upstroke at a voltage 5-20 mv depolarized from the normal resting potential (near-180 mv). the "action potentials" are long-lasting, 1-2 min and at the peak reach a membrane potential near-40 mv. a 2-to 8-fold increase of membrane conductance ...1976130926
Displaying items 1201 - 1300 of 5889