Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
15n nmr studies of nitrogen metabolism in intact mycelia of neurospora crassa.suspensions of intact mycelia of neurospora crassa grown in medium containing 15nh4cl have been found to give well-resolved 15n nuclear magnetic resonance spectra for metabolites that play crucial roles in intermediary nitrogen metabolism. these include the amide nitrogen of glutamine, the alpha-amino nitrogens of glutamate and other amino acids, the guanidino nitrogens of arginine, the ureido nitrogen of citrulline, the side-chain nitrogens of ornithine or lysine, or both, and uridine diphospha ...19816453347
heat-sensitive mutant strain of neurospora crassa, 4m(t), conditionally defective in 25s ribosomal ribonucleic acid production.a heat-sensitive mutant strain of neurospora crassa, 4m(t), was studied in an attempt to define its molecular lesion. the mutant strain is inhibited in conidial germination and mycelial extension at the nonpermissive temperature (37 degrees c). macromolecular synthesis studies showed that both ribonucleic acid (rna) and protein syntheses are inhibited when 4-h cultures are shifted from 20 to 37 degrees c. density gradient analysis of ribosomal subunits made at 37 degrees c indicated that strain ...19816242828
transcripts and processing patterns for the ribosomal rna and transfer rna region of neurospora crassa mitochondrial dna. 19816450763
the ontogeny of lipid bodies (spherosomes) in plant cells : ultrastructural evidence.maturing embryos of 16 oil plants, anise suspension culture cells, and neurospora crassa cells were prepared for electron microscopy at different stages during massive lipid accumulation. lipid-rich structures of certain species were best preserved by dehydration of fixed tissues in ethanol without propylene oxide, embedding in spurr's medium, and polymerization at room temperature. in all cells examined, spherical lipid bodies (spherosomes) showed a moderately osmiophilic, amorphous matrix and ...198124301718
the biphasic fluence response of carotenogenesis in neurospora crassa: temporary insensitivity of the photoreceptor system.whether or not illumination is continuous or interrupted during the span in which increasing illumination time periods (i.e., increasing fluences) have no different effect on carotenogenesis is optional, in regard to the amount of carotenoids produced (revealing the plateau of the biphasic fluence response curve). this indicates temporary insensitivity. when the time delay between the onsets of the initial and second illumination is extended beyond the expanse of the plateau, the amount of carot ...198124301981
enzymatic alterations secondary to adenyl cyclase deficiency in the cr-1 (crisp) mutant of neurospora crassa: anomalies of the beta-glucosidase system. 19816458343
timing of nuclear division cycle in neurospora crassa.the timing of the nuclear division cycle in neurospora crassa was studied by inhibiting dna synthesis with hydroxyurea added to exponentially growing cultures at concentrations that do not inhibit cytoplasmic growth. after the addition of hydroxyurea only the nuclei that have passed the s-phase divide, and therefore by counting the increase in the average number of nuclei per hypha, the stage in the cycle in which completion of s phase occurred was determined in different nutritional conditions ...19816456271
alternate mechanism for amino acid entry into neurospora crassa: extracellular deamination and subsequent keto acid transport.the growth of the pm nbg mutant strain of neurospora crassa was inhibited by the amino acid analog para-fluorophenylalanine despite the fact that none of the three constitutive amino acid permeases is functional in this strain. this observation led to the detection of both a deaminase which was released into the growth medium in response to para-fluorophenylalanine and a keto acid transport system which allowed entry of the resulting keto acid into the cell. the transported keto acid was recover ...19816452443
electrophoretic analysis of the plasma membrane proteins of a mutant of neurospora crassa which lacks a cell wall.the plasma membrane proteins of a mutant of neurospora crassa (fgsc no. 326) which lacks a cell wall were analyzed by two-dimensional polyacrylamide gel electrophoresis. approximately 180 different proteins were detected in purified plasma membrane preparations. nonpermeating labeling experiments indicated that approximately 40% of these proteins were exposed on the extra-cytoplasmic surface of the plasma membranes of these cells. the studies demonstrate the complexity of the protein composition ...19816452167
assay and characteristics of circadian rhythmicity in liquid cultures of neurospora crassa.previous work on circadian rhythms of neurospora crassa has been done almost exclusively with cultures expressing rhythmic conidiation and growing on solid agar medium. such conditions severely restrict the kinds of biochemical experiments that can be carried out. we have now developed systems which allow indirect assay of circadian rhythmicity in liquid culture. neurospora was grown in glucose and acetate liquid media under conditions which result in a range of growth rates and morphologies. li ...198116661683
inactivation of normal and mutant neurospora crassa conidia by visible light and near-uv: role of 1o2, carotenoid composition and sensitizer location. 19816454899
subunit structure of anthranilate synthase from neurospora crassa: preparation and characterization of a protease-free form. 19816453559
the effect of polyethylene glycol on the dna uptake in neurospora crassa. 19816456636
independent localization and regulation of carbamyl phosphate synthetase a polypeptides of neurospora crassa.carbamyl phosphate synthetase a is a two-polypeptide, mitochondrial enzyme of arginine synthesis in neurospora. the large subunit is encoded in the arg-3 locus and can catalyze formation of carbamyl-p with ammonia as the n donor. the small subunit is encoded in the unlinked arg-2 locus and imparts to the holoenzyme the ability to use glutamine, the biological substrate, as the n donor. by using nonsense mutations of arg-3, it was shown that the small subunit of the enzyme enters the mitochrondri ...19816456400
studies on the structure-function relationships of neurospora crassa pyruvate kinase: refolding and reactivation following denaturation in guanidine hydrochloride. 19816451460
temperature compensation of circadian period length in clock mutants of neurospora crassa.temperature compensation of circadian period length in 12 clock mutants of neurospora crassa has been examined at temperatures between 16 and 34 degrees c. in the wild-type strain, below 30 degrees c (the "breakpoint" temperature), the clock is well-compensated (q(10) = 1), while above 30 degrees c, the clock is less well-compensated (q(10) = 1.3). for mutants at the frq locus, mutations that shorten the circadian period length (frq-1, frq-2, frq-4, and frq-6) do not alter this temperature compe ...198116662086
larger precursors of mitochondrial translation products in neurospora crassa. indications for a precursor of subunit 1 of cytochrome c oxidase.specific labeling in vivo of the formylated n termini of mitochondrial translation products revealed that some mitochondrially synthesized proteins were not labeled this way. as a consequence, it was worthwhile considering that larger precursor proteins of mitochondrial translation products exist. although we used a rapid isolation procedure, only after 2-h of labeling in the presence of cycloheximide, could three additional mitochondrial translation products (molecular mass 45, 36, and 25 kilod ...19816276171
highly conserved gc-rich palindromic dna sequences flank trna genes in neurospora crassa mitochondria.in sequencing a 2200 bp region of the neurospora crassa mitochondrial dna encoding the 3' end of the large rrna gene and a cluster of six trna genes, we have found that the trna genes are flanked by highly conserved gc-rich palindromic dna sequences. an 18 bp long core sequence, 5'-cc ctgcag ta ctgcag gg-3', containing two closely spaced pst i sites, is common to all these palindromic sequences. each of the eight pst i sites mapped in the 2200 bp region consists of two closely spaced pst i sites ...19816276013
s1 nuclease does not cleave dna at single-base mis-matches.three assays have been designed to detect the cleavage of duplex phi x174 dna at single-base mis-matches. studies with s1 nuclease failed to detect cleavage at mis-matches. s1 nuclease digestion at 37 and 55 degrees c failed to produce a preferential degradation of a multiply mis-matched heteroduplex when compared to a mis-match-free homo-duplex as analyzed by sedimentation on sucrose gradients. other heteroduplex templates were not cleaved by s1 nuclease at a defined single-base mis-match when ...19816274410
aminotransferase study of neurospora crassa ser-3 versus wild type st4a. 19816459952
an isolated pseudogene related to the 5s rna genes in neurospora crassa. 19816458767
purification and characterization of the plasma membrane atpase of neurospora crassa.the plasma membrane of neurospora crassa contains a proton-translocating atpase, which functions to generate a large membrane potential and thereby to drive a variety of h+-dependent co-transport systems. we have purified this atpase by a three-step procedure in which 1) loosely bound membrane proteins are removed by treatment with 0.1% deoxycholate; 2) the atpase is solubilized with 0.6% deoxycholate in the presence of 45% glycerol; and 3) the solubilized enzyme is purified by centrifugation th ...19816457834
isolation and characterization of plasma membranes from wild type neurospora crassa.a method has been developed to isolate plasma membranes with high atpase activity from wild type neurospora. cells are treated with snail enzyme to weaken their cell walls, disrupted by gentle homogenization in a medium designed to keep mitochondria and other organelles intact, and fractionated by differential centrifugation. after removal of mitochondria, several higher speed particulate fractions (particularly one sedimenting at 40,000 x g) contain an atpase that can be identified as the plasm ...19816457833
a novel extranuclear mutant of neurospora with a temperature-sensitive defect in mitochondrial protein synthesis and mitochondrial atpase.[c93] is a novel, extranuclear mutant of neurospora crassa which has a normal mitochondrial phenotype when grown at 25 degrees, but which is deficient in cytochromes b and aa3 when grown at 37 degrees (pittenger and west 1979). in the present work, the phenotype of [c93] was characterized in greater detail. when [c93] is grown at 37 degrees, the rate of mitochondrial protein synthesis is decreased to approximately 25% that of wild type; the ratio of mitochondrial small to large ribosomal subunit ...19816261083
purification and some properties of nad-glycohydrolase from conidia of neurospora crassa.nad-glycohydrolase from conidia of neurospora crassa was purified by affinity chromatography, using 4-methylnicotinamide adenine dinucleotide as ligand immobilized onto sepharose through a hydrophilic spacer arm. the pure enzyme is a glycoprotein with an isoelectric point of 5.5 and a molecular weight of 33 000 as determined by sodium dodecylsulphate gel electrophoresis. the specific activity is the highest so far found for nad-glycohydrolases and in various aspects the enzyme is different from ...19816260480
protein kinase activities in neurospora crassa. 19816260035
genetic analysis of ad-3 mutants induced by af-2 and two other nitrofurans in neurospora crassa.our previous studies have shown that the nitrofurans af-2, sq18506, and fanft are potent mutagens in neurospora crassa. the genetic damage produced by these chemicals at the ad-3 region in n crassa has been characterized by a series of genetic tests. the results of these tests indicate that all three agents induce a high frequency of point mutations and probably a low frequency of multilocus deletions. a comparison of the complementation patterns among the af-2--induced ad-3b mutants and those i ...19816165577
deficient cyclic adenosine 3',5'-monophosphate control in mutants of two genes of neurospora crassa.strains of neurospora crassa mutant in either of two genes, crisp-1 (cr1) and frost (fr), showed no increase of cyclic adenosine 3',5'-monophosphate (cyclic amp) levels when subjected to several treatments which produce large increases of cyclic amp in wild-type neurospora. evidently, the previously reported deficiencies of adenylate cyclase in these mutants were sufficient to block the normal increases. this fact suggests that both mutants could be used to help determine which control phenomena ...19816100957
genetic and biochemical characterization of d-arabinose dehydrogenase from neurospora crassa.d-arabinose dehydrogenase has been purified to homogeneity from wild-type neurospora crassa 74-a (fgsc 262) and from two colonial mutants, col-15a (fgsc 1391) and col-16a (fgsc 1349), found to contain more of the enzyme. the enzymes were characterized by measurement of several kinetic and physicochemical parameters. the enzymes were the same in all characteristics studied thus far. immunological studied performed with enzyme preparations from the three strains showed antigenic identity and indic ...19816450742
the isolation of mms- and histidine-sensitive mutants in neurospora crassa.a simple method of replica plating has been used to isolate mutants of neurospora crassa that have increased sensitivity to methyl methanesulfonate (mms) and/or to histidine. twelve mutants with increased sensitivity to mms and one mutant with increased sensitivity to histidine showed mendelian segregation of the mutant phenotypes. three mutants were mapped to loci not previously associated with mms sensitivity. two other were allelic to the uv- and mms-sensitive mutant, mei-3. survival curves i ...19816456170
studies on phospholipase activities in neurospora crassa conidia. 19816452858
glutamate synthase levels in neurospora crassa mutants altered with respect to nitrogen metabolism.glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. glutamate synthase activity has been determined in a number of neurospora crassa mutant strains with various defects in nitrogen metabolism. of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutam ...19816152851
effect of the gln-1b mutation on nitrogen metabolite repression in neurospora crassa.in neurospora crassa, synthesis of the enzymes of nitrate assimilation, nitrate reductase and nitrite reductase, was repressed by the presence of ammonium, glutamate, or glutamine. this phenomenon was a manifestation of the regulatory process termed nitrogen metabolite repression whereby alternative pathways of nitrogen acquisition are not expressed in cells enjoying nitrogen sufficiency. however, the glutamine synthetase mutant gln-1b had derepressed levels of the nitrate assimilation enzymes. ...19816109713
regulation of polyamine synthesis in relation to putrescine and spermidine pools in neurospora crassa.polyamine pools were measured under various conditions of high and low concentrations of cytosolic ornithine with the wild-type and mutant strains of neurospora crassa. in minimal medium, the wild-type strain has 1 to 2 nmol of putrescine and approximately 14 nmol of spermidine per mg (dry weight); no spermine is found in n. crassa. exogenous ornithine was found to cause a rapid, but quickly damped, increase in the rate of polyamine synthesis. this effect was greater in a mutant (ota) unable to ...19816450741
[camp participation in the light regulation of carotenoid synthesis in neurospora crassa]. 19816265179
negative cooperativity in the interaction of fructose 1,6-diphosphate with pyruvate kinase of neurospora crassa. 19816453017
alkaline protease from neurospora crassa. purification and partial characterization.a simple purification procedure has been developed for the extracellular alkaline protease from neurospora crassa. key steps in the purification were: 1) the choice of gelatin as the protein inducer, which induces optimally at a much lower concentration than other commonly employed protein inducers; 2) heat treatment, during which the inducer is digested by the protease; and 3) a concentration step that eliminates the usual precipitation procedures and removes much of the digested protein induce ...19816450209
in vitro complementation of assimilatory nad(p)h-nitrate reductase from mutants of chlamydomonas reinhardii.in vitro complementation of the soluble assimilatory nad(p)h-nitrate reductase (nad(p)h:nitrate oxidoreductase, ec 1.6.6.2) was attained by mixing cell-free preparations of chlamydomonas reinhardii mutant 104, uniquely possessing nitrate-inducible nad(p)h-cytochrome c reductase, and mutant 305 which possesses solely the nitrate-inducible fmnh2- and reduced benzyl viologen-nitrate reductase activities. full activity and integrity of nad(p)h-cytochrome c reductase from mutant 104 and reduced benzy ...19816452169
identification of the product of the major regulatory gene of the nitrogen control circuit of neurospora crassa as a nuclear dna-binding protein.the nitrogen regulatory circuit of neurospora crassa contains an entire set of unlinked structural genes which specify nitrogen catabolic enzymes. these genes are controlled as a group by a major regulatory gene, designated nit-2, which "turns on" their expression in a positive fashion. moreover, expression of these same structural genes is repressed when the cells contain sufficient nitrogen; the active repressor metabolite has been identified as glutamine. it has been suggested that the nit-2 ...19816450203
synthesis of photoreactive tryptophan analogs: enzymatic conversion of azidoindoles to azidotryptophans.four photoreactive azidoindoles, 4, 5, 6, and 7 azidoindole, were synthesized and converted to the corresponding azidotryptophans by a crude enzyme preparation of tryptophan synthetase from neurospora crassa.19817339614
liposome-mediated genetic transformation of neurospora crassa.transformation of neurospora crassa spheroplasts is reported for three different genes, using uncloned neurospora dna, both naked and encapsulated in synthetic phosphatidylserine liposomes. whereas transformation by naked dna is dnase-sensitive, that by liposomes is not. per unit of transforming dna, liposome transformation is significantly more efficient than that with naked dna, ranging from 19x for the am gene to 41x for pyr-3. levels of activity of pyr-3 and am transformants, and segregation ...19816460917
sex-hormones in neurospora crassa. differences in the biological property of the hormonal extracts of fertile and sterile strains.sexual hormones, isolated from the wild strains and sterile mutants of neurospora crassa, were used for the improvement of fertility of sterile crosses, i. e., st. l. a x7232-a, st. l. a x 9312-a and st. l. a x 8455-a. improvement of fertility was observed in case of the cross st. l. a x 9312-a. of the different extracts, hormonal substances present in the extract of 7232-a (sterile mutant) and also of the wild types (em a, em a, st. l. a, st. l. a) exerted the most prominent effects. for the ex ...19816458180
the regulation of nitrate assimilation in neurospora crassa: biochemical analysis of the nmr-1 mutants.neurospora crassa nmr-1 mutants, selected on the basis of their sensitivity to chlorate in the presence of glutamine, have elevated levels of the nitrate assimilation enzymes, nadph-nitrate reductase and nad(p)h-nitrite reductase. immunoelectrophoretic determinations show that the higher nitrate reductase activities in nmr-1 mutants are due to greater enzyme concentrations. the half-life of nitrate reductase in these mutants is unaltered. as in wild-type, expression of nitrate assimilation in nm ...19816457234
the regulation of nitrate assimilation in neurospora crassa: the isolation and genetic analysis of nmr-1 mutants.four mutants of neurospora crassa have been isolated which have altered regulation of nitrate reductase. they each carry a mutation which results in derepressed synthesis of nitrate reductase even in the presence of glutamine. they map to a single locus which has been designated nmr-1 and which is located between am and gln on linkage group vr. the mutations appear to affect only nitrate assimilation. the nit-2, nit-3 and nit-4/5 mutations are epistatic to nmr-1 since the double mutants have the ...19816457233
mitochondrial variants of neurospora intermedia from nature.from a sample of 122 natural isolates of neurospora intermedia collected recently from around the world, five variants had erratic stop-start growth patterns reminiscent of the phenotype of "stopper" laboratory extranuclear mutants of neurospora crassa. like laboratory isolated mutants, the natural "stopper" variants were sterile as protoperithecial parents and transmitted the variant growth phenotypes very inefficiently, if at all, as male parents. heterokaryon tests could not be made because o ...19826303535
structure and organization of trna, rrna, and protein genes in neurospora crassa mitochondria.our studies on neurospora crassa mitochondria have included sequence analysis of trnas, mapping and cloning of the trna, rrna, and protein genes and the dna sequence analysis of these genes. results from trna sequence analyses explain how the mitochondrial protein synthesizing system can function with a much smaller number of trnas than other systems. mapping studies have shown that the two rrna genes and almost all of the trna genes are clustered onto a third of the mitochondrial genome. the tw ...19826300028
transformation of neurospora crassa utilizing recombinant plasmid dna. 19826279089
gene cloning in neurospora crassa. 19826276097
separation of neurospora crassa myo-inositol-1-phosphate synthase from glucose-6-phosphate dehydrogenase by affinity chromatography.the purification of neurospora crassa myo-inositol-1-phosphate synthase (ec 5.5.1.4) was studied by affinity chromatography using the substrate (glucose-6-phosphate), the inhibitor (pyrophosphate), the coenzyme (nad+) and the coenzyme analogues (5'amp and cibacron blue f3g-a) of the enzyme as adsorbents attached to agarose gel. myo-inositol-1-phosphate synthase could be separated completely from the contaminating substance, glucose-6-phosphate dehydrogenase (ec 1.1.1.49), on blue sepharose cl-6b ...19826214775
nitrogen metabolite repression of fluoropyrimidine resistance and pyrimidine uptake in neurospora crassa.wild type neurospora crassa was shown to be more resistant to 5-fluoro-uracil, 5-fluoro-uridine and 5-fluoro-2'-deoxyuridine in the presence of ammonia than in its absence. this differential resistance may in part be accounted for by the observation that both uracil and uridine uptake in germinating conidia is under nitrogen metabolite regulation. the uptake of uracil and uridine is increased on poor nitrogen sources in wild type, is unaffected by nitrogen source in a nit-2 mutant strain while a ...19826213838
the imported preprotein of the proteolipid subunit of the mitochondrial atp synthase from neurospora crassa. molecular cloning and sequencing of the mrna.the proteolipid subunit of the mitochondrial atp synthase from neurospora crassa is an extremely hydrophobic protein of 81 amino acid residues, which is imported into mitochondria as a precursor of mol. wt. 15 000. the primary structure of the imported form has now been determined by isolating and analyzing cdna clones of the preproteolipid mrna. an initial cdna clone was identified by hybridizing total polyadenylated rna to pooled cdna recombinant plasmids from an ordered clone bank and subsequ ...19826329691
purification and characterization of neurospora crassa n-acetyl galactosaminoglycan deacetylase.1. n-acetyl galactosaminoglycan deacetylase was purified from neurospora mycelium 215-fold in 25% yield to electrophoretic homogeneity. a single band corresponding to a molecular weight of 76,000 was obtained by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. 2. the enzyme activity had ph optima at ph 5.0 and 9.0. sodium molybdate, 2 mm, stimulated enzyme activity 4-fold at ph 5.0 but had no effect at ph 9.0. cupric ion, 1 mm, inhibited activity by more than 85% at ph 5.0 and 9.0. the ...19826217857
mutants affecting amino acid cross-pathway control in neurospora crassa. 19826211391
energy requirement for the mobilization of vacuolar arginine in neurospora crassa.the bulk of the intracellular arginine pool in exponentially growing mycelia of neurospora crassa is sequestered in the vacuoles. vacuolar arginine effluxes from the vacuoles into the cytosol and is catabolized to ornithine and urea upon nitrogen starvation. the energy requirement for mobilization has been studied by treating nitrogen-starved mycelia with inhibitors or respiration or glycolysis or an uncoupler of respiration. mobilization was inhibited by the inhibitors or the uncoupler of respi ...19826461635
purification and characterisation of a pore protein of the outer mitochondrial membrane from neurospora crassa.the major protein of the outer mitochondrial membrane of neurospora was purified. on dodecylsulfate-containing gels it displayed a single band with an apparent molecular weight of 31 000. reconstitution experiments with artificial lipid bilayers showed that this protein forms pores. pore conductance was dependent on the voltage across the membrane. the protein inserted into the membrane in an oriented fashion, the membrane current being dependent on the sign of the voltage. single pore conductan ...19826210532
physiology of ammonium assimilation in neurospora crassa.in neurospora crassa the assimilation of high and low concentrations of ammonium occurs by two different pathways. when the fungi are growing exponentially on ammonium excess, this compound is fixed by a glutamic dehydrogenase and an octameric glutamine synthetase (gs). the synthesis of this gs polypeptide (beta) is regulated by the nitrogen source present in excess; being higher on glutamate, intermediate on ammonium, and lower on glutamine. when n. crassa is growing in fed-batch ammonium-limit ...19826120927
phosphate mediated regulation of some of the enzymes of carbohydrate metabolism in neurospora crassa. 19826210569
effects of membrane atpase inhibitors on light-induced phase shifting of the circadian clock in neurospora crassa.effects of several membrane atpase inhibitors on light-induced phase shifting of the circadian conidiation rhythm in neurospora crassa were examined using mycelial discs in liquid culture. suppression of phase shifting by the inhibitors was strongly dependent on the ph of the liquid medium in which the discs were cultured during the time from light-dark transition (beginning of free-run) to light irradiation. when discs were cultured in ph 6.7 medium, azide, the inhibitors of plasma membrane atp ...198216662260
binding and screening by cations and the effect on exogenous nad(p)h oxidation in neurospora crassa mitochondria.1. the uncoupled oxidation of exogenous nadh by mitochondria from neurospora crassa has a ph optimum at 7.0. in the presence of edta (1 mm) the optimum is at ph 6.5; maximal inhibition (65%) occurs at ph 7.2. this is comparable to the results with higher plant mitochondria. 2. the corresponding ph optima for nadph oxidation are 7.75 (control), 7.0 (+ edta) and 8.0 (effect of edta), respectively. nadph oxidation is completely inhibited by edta at ph 8.0. these ph optima are all about 1 higher tha ...19826461553
radioautographic detection of macromolecules involved in the synthesis of neurospora crassa cell wall. 19826213305
biosynthesis of glyoxysomal enzymes in neurospora crassa. 19826212015
two types of microbodies in neurospora crassa. 19826212014
postreplication repair in neurospora crassa.changes in the molecular weight of nascent dna made after ultraviolet (uv) irradiation have been studied in the excision-defective neurospora mutant uvs-2 using isotopic pulse labeling, alkaline gradient centrifugation and alkaline filter elution. both the size of nascent dna and the rate of incorporation of label into dna was reduced by uv light in a dose dependent manner. however, this dna repair mutant did recover the ability to synthesize control-like high molecular weight dna 3 hours after ...19826211589
relationship between the composition of phospholipids and respiratory activity of choline-deficient mutants of neurospora crassa.phosphatidylcholine is one of the most frequent phospholipid components of the inner mitochondrial membrane of neurospora crassa. quantitative analysis of phosphlipids of the wild strain of neurospora crassa and of its two cho mutants showed that these strains did not significantly differ in the content of phosphatidylcholine. mutants cultivated in a medium without choline contained, as compared with the wild strain, an increased amount of phosphatidylserine and a decreased quantity of phosphati ...19826211400
regulation of l-amino acid oxidase and of d-amino acid oxidase in neurospora crassa.neurospora crassa possesses an inducible l-amino acid oxidase that is expressed only when cells are derepressed for nitrogen in the presence of an amino acid. enzyme synthesis requires both induction by an amino acid and simultaneous nitrogen catabolite derepression. carbon limition in the presence of an amino acid does not permit induction of l-amino acid oxidase. the nit-2 gene is a major regulatory locus which is believed to mediate nitrogen catabolite repression in neurospora. mutants of nit ...19826125872
effect of the nitrogen source on glutamine and alanine biosynthesis in neurospora crassa. an in vivo 15n nuclear magnetic resonance study.the influences of different nitrogen sources on the relative rates of biosynthesis of glutamine and alanine have been studied by 15n nuclear magnetic resonance spectroscopy of intact neurospora crassa mycelia suspensions. the rate of glutamine synthesis was fastest after growth in media deficient in free ammonium ion, whereas it was slowest following growth in media containing both glutamic acid and glutamine. the reverse trend was observed for the biosynthesis of alanine. a competition between ...19826128342
developmental regulation of nad+ kinase in neurospora crassa.the specific activity of nad+ kinase (atp:nad+ 2'-phosphotransferase, ec 2.7.1.23) from neurospora crassa shows sharp peaks when the organism enters a new developmental stage of the asexual life cycle: the peaks are observed during hydration and germination of conidia, at the transition from exponential to stationary growth and at the photostimulated conidiation. as stimulation of nad+ kinase activity by light in conidiating mycelium is not sensitive to translation inhibitors, the activation of ...19826303242
effect of 2,4,5-trichlorophenol on hyphal membrane potentials in rhythmic mutants of neurospora crassa.the uncoupler 2,4,5-trichlorophenol (tcp) was used to test for differences in maintaining the hyphal membrane potentials in the wild type and rhythmic mutants of neurospora crassa. trichlorophenol (0.1 mmol·1(-1)) resulted in a depolarization of 93 mv (wild type) and 144 mv in the mutant clock. a total recovery was achieved in both strains after washing out the uncoupler. the circadian conidiation mutant band was more sensitive than the two other strains and showed two different reaction pattern ...198224257777
cloning of the am (glutamate dehydrogenase) gene of neurospora crassa through the use of a synthetic dna probe.in a previous study the alteration in the amino acid sequence of neurospora crassa nadp-specific glutamate dehydrogenase (gdh) resulting from two mutually compensating frameshift mutations was used to deduce the first 17 nucleotides of the coding sequence of the am gene. in the work reported here, a synthetic 17-mer corresponding to the deduced sequence was shown to hybridize strongly to a 9-kb hindiii fragment from n. crassa wild-type dna but not to any corresponding fragment from the dna of a ...19826299898
[properties of polyphosphate phosphohydrolase of the "leaky" mutant neurospora crassa with respect to the specific enzyme].some properties of polyphosphate phosphohydrolase from n. crassa strain ad-6.28610a and from its mutant with a decreased polyphosphate phosphohydrolase activity were compared. it was shown that the ph optimum for both enzyme species lies within the range of 7.1-7.3; the temperature optimum is 45 degrees. the mutant polyphosphate phosphohydrolase has a v value, which is 2 times less than that of the parent strain, and possesses a higher thermal inactivation stability. the enzymes of both cultures ...19826297621
adenosine kinase-deficient mutant of neurospora crassa.tubercidin-resistant mutant strains of neurospora crassa were isolated, and at least one appeared to be deficient in adenosine kinase. no significant differences in [8-14c]adenosine labeling of purine nucleotides or nucleosides were found between the wild type and the adenosine kinase-deficient strains.19826292168
guanine uptake and metabolism in neurospora crassa.guanine is transported into germinated conidia of neurospora crassa by the general purine base transport system. guanine uptake is inhibited by adenine and hypoxanthine but not xanthine. guanine phosphoribosyltransferase (gprtase) activity was demonstrated in cell extracts of wild-type germinated conidia. the km for guanine ranged from 29 to 69 micro m in gprtase assays; the ki for hypoxanthine was between 50 and 75 micro m. the kinetics of guanine transport differ considerably from the kinetics ...19826174500
a simplified method for the simultaneous detection of intragenic and intergenic mutations (deletions) in neurospora crassa. 19826211615
circadian rhythms in neurospora crassa: a mutation affecting temperature compensation.the circadian rhythm of conidiation (spore formation) in neurospora crassa is known to be temperature compensated, that is, the period is only slightly affected by the incubation temperature. thus, the q10 (the relative rate enhancement corresponding to a 10 degrees c rise in temperature) of the rhythm of the bd csp strain from 14 to 30 degrees c was 1.1, whereas the q10 of the uncompensated growth rate in the same interval was 2.4. a mutation at the cel locus resulted in loss of the temperature ...19826461008
energetics of vacuolar compartmentation of arginine in neurospora crassa.the energy requirements for the uptake and retention of arginine by vacuoles of neurospora crassa have been studied. exponentially growing mycelial cultures were treated with inhibitors of respiration or glycolysis or an uncoupler of respiration. catabolism of arginine was monitored as urea production in urease-less strains. the rationale was that the rate and extent of such catabolism was indicative of the cytosolic arginine concentration. no catabolism was observed in cultures treated with an ...19826461634
properties of mitochondria as a function of the growth stages of neurospora crassa.the oxidative and phosphorylative properties of mitochondria isolated from neurospora crassa were investigated as a function of growth stage. the rates of oxidation of exogenous nadh and nadph varied independently of each other, thus ruling out the existence of only one unspecific dehydrogenase. two different pathways were involved in the oxidation of nad-linked substrates, as indicated by changes in the rate of oxygen uptake, the sensitivity to rotenone, and the efficiency of phosphorylation. o ...19826460022
metabolic sequestration of putrescine in neurospora crassa. 19826462139
effects of divalent metal ions and chelators on the structure of outer mitochondrial membranes from neurospora crassa. 198219431484
investigation of binding sites in the complex pyrimidine-specific carbamoyl-phosphate synthetase/aspartate carbamoyltransferase enzyme of neurospora crassa.the pyr-3 gene of neurospora crassa codes for the bifunctional enzyme pyrimidine-specific carbamoyl-phosphate synthetase/aspartate carbamoyltransferase (carbon dioxide: ammonia ligase (adp-forming, carbamate-phosphorylating)/carbamoylphosphate: l-aspartate carbamoyltransferase), ec 6.3.4.16/ec 2.1.3.2). we describe the investigation of substrate- and product-binding sites of the enzyme by affinity chromatography, using the ligands aspartate, glutamate, and adenosine 5'-diphosphate, and investiga ...19826217840
the effects of altered levels of phosphatidylcholine and phosphatidylethanolamine on fatty acid desaturase activity and sterol metabolism during temperature acclimation in a choline auxotroph of neurospora crassa.experiments were conducted to determine the effects of choline deprivation on levels of phospholipid fatty acids in a choline auxotroph (chol-1; chol-2) of neurospora crassa with respect to high (37 degrees c) and low (15 degrees c) growth temperatures and during acclimation following a shift from high to low temperature conditions. although grossly altered levels of phosphatidylethanolamine and phosphatidylcholine were observed at both temperatures, phospholipid fatty acid levels remained virtu ...19826217844
cycloheximide and heat shock induce new polypeptide synthesis in neurospora crassa.treatment of neurospora crassa with 0.1 microgram of cycloheximide per ml, a concentration which inhibited protein synthesis by about 70%, resulted in the greatly enhanced synthesis of at least three polypeptide bands with estimated molecular weights of 88,000, 30,000, and 28,000. a temperature shift from 25 to 37 degrees c resulted in the appearance of a single new polypeptide band of 70,000 daltons, the same size as the major heat shock-induced proteins observed in species of drosophila and di ...19826217413
l-myoinositol-1-phosphate synthase from neurospora crassa: purification to homogeneity and partial characterization. 19826216853
characterization of mms-sensitive mutants of neurospora crassa.several mms-sensitive mutants of neurospora crassa were compared with the wild-type strain for their relative sensitivities to uv, x-ray, and histidine. they were also compared for the frequency of spontaneous mutation at the loci which confer assistance to p-fluorophenylalanine. the mutants were also examined for possible defects in meiotic behavior in homozygous crosses and for any change in the inducible dna salvage pathways (as indicated by their ability to utilize dna as the sole phosphate ...19826216404
physiological adaptation to the loss of amino acid transport ability.a strain of neurospora crassa devoid of constitutive amino acid transport ability can utilize arginine as the sole nitrogen source. nitrogen starvation, presence of arginine, and mutational inactivation of the general permease are key factors in signaling production of an extracellular enzyme which removes the alpha-amino group from the amino acid.19826214547
role of sulfhydryl compounds in the control of tyrosinase activity in neurospora crassa.it is known that neurospora crassa mycelia cultured in standard concentrations (76 to 190 micrograms/ml) of sulfate accumulate a low molecular weight inhibitor of tyrosinase (monophenol, dihydroxyphenylalanine: oxygen oxidoreductase; ec 1.14.1.18.1.). this is not observed in cultures grown under sulfate-limiting conditions. the chemical nature of tyrosinase inhibition was investigated. it was shown to be due to the low molecular weight sulfhydryl fraction of the extracts, in which glutathione is ...19826219663
chromosomal loci of neurospora crassa. 19826219280
regulation of synthesis of ribosomal protein in neurospora crassa. 19826217082
the effects of temperature acclimation on membrane sterols and phospholipids of neurospora crassa.experiments were conducted to examine the effects of temperature acclimation on sterol and phospholipid biosynthesis in neurospora crassa. cultures grown at high (37 degrees c) and low (15 degrees c) temperatures show significant differences in free and total sterol content, sterol/phospholipid ratios and distribution of major phospholipid species in total lipids and two functionally distinct membrane fractions. the ratio of free sterols to phospholipids in total cellular lipids from 15 degrees ...19826217843
inhibition of the plasma membrane [h+]-atpase of neurospora crassa by n-ethylmaleimide. protection by nucleotides.pre-incubation of the plasma membrane [h+]-atpase of neurospora crassa with the sulfhydryl reagent, n-ethylmaleimide (nem), leads to a marked inhibition of atpase activity. loss of activity depends upon preincubation ph and follows pseudo-first order kinetics with respect to nem concentration. mgatp, the physiological substrate for atpase activity, protects against nem inactivation with an average dissociation constant of 1.5 mm at 0 degrees c. this value agrees well with the measured km for mga ...19826214555
anthranilate synthase of neurospora crassa: reaction and labeling with glutamine analogs. 19826218784
a regulatory phenotype associated with the en-am 1 mutant of neurospora crassa.we have investigated the nature of the en-am1 mutant of neurospora crassa and have found that it affects the regulation of proline oxidase and utilisation of other nitrogen sources. this mutant is closely linked to the gln gene but not allelic with it. data from crosses suggest that the two genes he on opposite sides of the in1 gene on linkage group vr.198224186376
intracellular localization of nitrate reductase in neurospora crassa.nitrate reductase was localized in mycelial cells of neurospora crassa by immunohistochemical labeling with ferritin. the enzyme is found in the cell wall-plasmalemma region and in the tonoplast membranes.198216662763
phase shifting of the circadian clock by diethylstilbestrol and related compounds in neurospora crassa.phase shifts of the circadian conidiation rhythm in neurospora crassa were induced by 3-hour treatments of mycelia in liquid medium with diethylstilbestrol (des), dienestrol (die), hexestrol (hex), diethylstilbestroldipropionate (desp), and dienestroldiacetate (diea). over a 24-hour period beginning 24 hours after the transition from light to constant dark, maximum phase shifts occurred about 36 hours. des was the most effective of the drugs tested, giving 10-hour phase advances at 20 micromolar ...198216662655
reduction of exogenous cytochrome c by neurospora crassa conidia: effects of superoxide dismutase and blue light.the reduction of externally added cytochrome c by neurospora crassa conidia was observed. the reduction was stimulated by antimycin a and suppressed partially by superoxide dismutase. when conidia were treated with diethyldithiocarbamate, which inactivated endogenous superoxide dismutase, the cytochrome c reduction was stimulated. blue light also stimulated the cytochrome c reduction. azide, which inhibits photochemical reactions mediated by flavins, suppressed the blue light effect. superoxide ...19826288655
soluble adenylate cyclase activity in neurospora crassa.a soluble form of adenylate cyclase was extracted from mycelia of neurospora crassa wild-type strains. this enzyme activity was purified by chromatography on hexyl-amino-sepharose, agarose and blue sepharose and preparative polyacrylamide-gel electrophoresis. on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, peak fractions from the later purification steps showed a main polypeptide band with an apparent molecular weight of about 66 000. the following hydrodynamic and molecular param ...19826217814
the synthesis of alkaline phosphatase in neurospora crassa.mutations which affect the regulation of neurospora repressible alkaline phosphatase do so by altering the rate of de novo alkaline phosphatase synthesis. in regulatory mutants the rate of alkaline phosphatase polypeptide synthesis can vary over a 1000-fold range. following transfer to phosphate-free medium, the wild-type cell is capable of increasing the rate of synthesis of alkaline phosphatase molecules within 30-45 min.19826217811
polyamine-deficient neurospora crassa mutants and synthesis of cadaverine.the polyamine path of neurospora crassa originates with the decarboxylation of ornithine to form putrescine (1,4-diaminobutane). putrescine acquires one or two aminopropyl groups to form spermidine or spermine, respectively. we isolated an ornithine decarboxylase-deficient mutant and showed the mutation to be allelic with two previously isolated polyamine-requiring mutants. we here name the locus spe-1. the three spe-1 mutants form little or no polyamines and grow well on medium supplemented wit ...19826214545
folding of the mitochondrial proton adenosinetriphosphatase proteolipid channel in phospholipid vesicles.the mitochondrial h+-atpase proteolipid from neurospora crassa was incorporated into small unilamellar dimyristoylphosphatidylcholine vesicles and its conformation determined by circular dichroism spectroscopy (cd). while the largely alpha-helical conformation is relatively independent of the method of incorporation into vesicles, i.e., rehydration, detergent dialysis, or detergent dilution, the proteolipid conformation was significantly different in detergent micelles and in organic solvents. o ...19826291595
nitrogen-15 spin-lattice relaxation times of amino acids in neurospora crassa as a probe of intracellular environment.the nitrogen-15 spin-lattice relaxation time, t1, and the nuclear overhauser enhancement (noe) have been measured for intracellular glutamine, alanine, and arginine in intact neurospora crassa mycelia to probe their various intracellular environments. the relaxations of 15n gamma of glutamine, 15n alpha of alanine, and 15n omega, omega ' of arginine in n. crassa were found, on the basis of their noe values, to be predominantly the result of 15n-h dipolar relaxation. these relaxations are therefo ...19826215941
circadian rhythms in neurospora crassa: oscillations in fatty acids. 19826215940
Displaying items 1801 - 1900 of 5889