TitleAbstractYear(sorted descending)
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.198216662592
nuclear buoyant density determination and the purification and characterization of wild-type neurospora nuclei using percoll density gradients.a procedure has been developed using percoll density gradients for the isolation and purification of nuclei from germinated conidia of wild-type neurospora crassa st. lawrence strain 74a. crude nuclei were purified isopycnically in gradients of percoll, which is silica coated with polyvinylpyrrolidone. a dna:rna:protein ratio of 1:3.5:6.5 was found in purified nuclei. cytoplasmic contamination was found to be negligible in the nuclear preparations, as determined by electron microscopy and by fol ...198216662561
structure of the outer mitochondrial membrane: ordered arrays of porelike subunits in outer-membrane fractions from neurospora crassa mitochondria.light-membrane fractions obtained by hypoosmotic lysis of neurospora crassa mitochondria exhibit buoyant densities and marker-enzyme activities characteristic of outer mitochondrial membranes. sds page of these membrane fractions indicates that a polypeptide of m(r) 31,000 is the main protein component. under negative-stain electron microscope examination many of the membranes in these fractions appear as large (0.5-1- mum diameter), collapsed vesicles. the surfaces of flattened, open (i.e., rip ...19826215413
identification and properties of an atpase in vacuolar membranes of neurospora crassa.using a vacuolar preparation virtually free of contamination by other organelles, we isolated vacuolar membranes and demonstrated that they contain an atpase. sucrose density gradient profiles of vacuolar membranes show a single peak of atpase activity at a density of 1.11 g/cm3. comparison of this enzyme with the two well-studied proton-pumping atpases of neurospora plasma membranes and mitochondria shows that it is clearly distinct. the vacuolar membrane atpase is insensitive to the inhibitors ...19826213602
isolation of mitochondrial porin from neurospora crassa. 19826290266
the functional unit of the arom conjugate in neurospora.the functional unit of arom polyenzyme conjugate of neurospora crassa was determined by analysis of radiation inactivation of each of the five activities in the conjugate. the functional targets for all five enzymes were in close agreement with the value of 300,000 obtained by conventional hydrodynamic procedure for the native dimeric structure. these data indicate that at least 95% of the functional enzyme system in crude extracts exists in a dimeric form and that both polypeptide chains of the ...19826212584
biosynthesis of mitochondrial porin and insertion into the outer mitochondrial membrane of neurospora crassa.mitochondrial porin, the major protein of the outer mitochondrial membrane is synthesized by free cytoplasmic polysomes. the apparent molecular weight of the porin synthesized in homologous or heterologous cell-free systems is the same as that of the mature porin. transfer in vitro of mitochondrial porin from the cytosolic fraction into the outer membrane of mitochondria could be demonstrated. before membrane insertion, mitochondrial porin is highly sensitive to added proteinase; afterwards it i ...19826290213
genetic and enzymatic characterization of the inducible glycerol dissimilatory system of neurospora crassa.the glycerol dissimilatory system in neurospora crassa was analyzed through the characterization of 18 glp- mutants which were isolated after inositol-less death and filtration enrichment. all mutants obtained by this procedure could be assigned to one of three complementation groups. the subsequent genetic characterization of these glp mutations revealed lesions on the i, ii, and vi chromosomes at the glp-1, glp-2, and glp-4 loci, each of which was subjected to fine-structure analysis. evidence ...19826284716
protein kinase activities in neurospora crassa. molecular properties. 19826287207
mechanisms for chromosomal aberrations in mammalian cells.experimental evidence is presented for the involvement of dna double-strand breaks in the formation of radiation-induced chromosomal aberrations. when x-irradiated cells were post-treated with single-strand specific neurospora crassa endonuclease (ne), the frequencies of all classes of aberration increased by about a factor 2. under these conditions, the frequencies of dna double-strand breaks induced by x-rays (as determined by neutral sucrose-gradient centrifugation), also increased by a facto ...19826287256
cross-pathway control of ornithine carbamoyltransferase synthesis in neurospora crassa.the pattern of cross-pathway regulation of the arginine synthetic enzyme ornithine carbamoyltransferase was investigated in neurospora crassa, using single and double mutant auxotrophic strains starved for their required amino acids. these experiments show that starvation for histidine, tryptophan, isoleucine, valine or arginine can result in derepression of ornithine carbamoyltransferase. methionine starvation also gave slight derepression, but starvation for lysine or leucine gave little or no ...19826214612
comparison of amino acid sequence and thermostability of tyrosinase from three wild type strains of neurospora crassa.the thermostability of tyrosinase from three wild type strains of neurospora crassa has been investigated. for this purpose a sequence comparison of two thermostable and one thermolabile tyrosinase isoenzyme was carried out. it revealed that at position 201 the thermostable enzyme forms share an aspartate residue in contrast to an asparagine residue in the thermolabile form. in addition, one of the thermostable isoenzymes displays five other substitutions. since the relative stability of the the ...19826210697
primary structure of tyrosinase from neurospora crassa. ii. complete amino acid sequence and chemical structure of a tripeptide containing an unusual align the four cyanogen bromide peptides of neurospora tyrosinase whose amino acid sequences were reported in the preceding paper, suitable methionine-containing overlap peptides were isolated. the required peptides were obtained by tryptic, peptic, and thermolytic digestion of the unmodified protein and of the maleylated derivative. from the partial sequence information of these peptides and a cyanogen bromide overlap peptide, the four cyanogen bromide fragments were aligned in the order cb3 ...19826210696
behaviour of dna-induced inositol-independent transformants of neurospora crassa in sexual crosses.treatment of inositolless (inl) strains of neurospora crassa with dna from the wild type (allo-dna) gives rise to inositol-independent (inl (+)) colonies. some of these dna-induced inl (+) strains (transformants) are sterile in sexual crosses on minimal medium that selects for the maintaining of the inl (+) character. the same inl (+) transformants, when crossed with an inl standard strain, are fertile on complete (inositol-containing) medium. there are, however, an increased number of unusual n ...198224270340
cyclic nucleotide phosphodiesterase activities in neurospora crassa.cyclic nucleotide phosphodiesterase activities in soluble neurospora crassa mycelial extracts were resolved into two peaks, phosphodiesterase i and ii, by chromatography on deae-cellulose columns. phosphodiesterase i hydrolysed cyclic amp and cyclic gmp equally well. phosphodiesterase ii was active on cyclic gmp but scarcely active on cyclic amp. phosphodiesterase i was resolved by gel filtration and sucrose-density-gradient centrifugation into three peaks having molecular weights of about 57 00 ...19826288007
regulation of l-phenylalanine ammonia-lyase by l-phenylalanine and nitrogen in neurospora crassa.neurospora crassa possesses an inducible l-phenylalanine ammonia-lyase that is expressed only when cells are derepressed for nitrogen in the presence of l-phenylalanine. enzyme synthesis requires both induction by l-phenylalanine and simultaneous nitrogen catabolite derepression. carbon limitation in the presence of phenylalanine does not elicit induction of l-phenylalanine ammonia-lyase. specific induction by l-phenylalanine is required, and other amino acids completely failed to induce any lya ...19826210688
regulation of ribosomal rna cistron number in a strain of neurospora crassa with a duplication of the nucleolus organizer region.some progeny from a cross of the translocation mutant t(vl leads to ivl)ar33 with wild-type neurospora crassa are double nucleolus organizer (dno) strains, usually displaying two distinct nucleolus organizer regions. the dno strain is sterile but displays the same growth response as normal laboratory strains of neurospora. we used dna-dna hybridization techniques to quantify the number of rrna cistrons in the dno mutant and its vegetative progeny. comparisons of the rate of hybridization of geno ...19826213268
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
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
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
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 was studied by affinity chromatography using the substrate (glucose-6-phosphate), the inhibitor (pyrophosphate), the coenzyme (nad+) and the coenzyme analogues (5'amp and cibacron blue f3g-a) of the enzyme as adsorbents attached to agarose gel. myo-inositol-1-phosphate synthase could be separated completely from the contaminating substance, glucose-6-phosphate dehydrogenase (ec, on blue sepharose cl-6b ...19826214775
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
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
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
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 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
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
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
highly conserved gc-rich palindromic dna sequences flank trna genes in neurospora crassa 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
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
inhibition of rna synthesis in neurospora crassa hyphae treated with picolinic acid.picolinic acid, a metal-chelating agent, blocks the nuclei of germinating conidia of neurospora crassa in the g1 phase. the addition of picolinic acid to exponentially growing cultures of n. crassa in glucose medium causes an immediate inhibition of growth. concentrations higher than 50 mm completely inhibit growth of mycelia, whereas lower concentrations (20-30 mm) give only a partial inhibition. picolinic acid, added at the concentration of 20 mm, immediately blocks the accumulation of stable ...19816173217
some kinetic properties of the tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa.the steady-state kinetic properties of purified tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa were examined. the results suggest that the enzyme obeys a rapid-equilibrium ordered mechanism, in which phosphoenolpyruvate is the first substrate to bind and 3-deoxy-d-arabino-heptulosonate 7-phosphate is the second product to be released, rather than a ping pong mechanism as has been reported previously. the inhibition by tryptophan was found to be p ...19816122442
control of the flux in the arginine pathway of neurospora crassa. modulations of enzyme activity and concentration.the influence of particular enzyme activities on the flux of metabolites in a pathway can be estimated by 'modulating' enzymes (i.e. changing turnover or concentration) and measuring the response in various parts of the system. by controlling the nuclear ration of two genetically different nuclear types in heterokaryons, the enzyme concentrations at four different steps in the arginine pathway were decreased over a range. this range was extended by the use of bradytrophs, mutant strains specifyi ...19816462136
occurrence of xanthine dehydrogenase in chlamydomonas reinhardii: a common cofactor shared by xanthine dehydrogenase and nitrate reductase.wild-type chlamydomonas reinhardii cells have xanthine dehydrogenase activity when grown with nitrate, nitrite, urea, or amino acid media. mutant strains 102, 104, and 307 of chlamydomonas, lacking both xanthine dehydrogenase and nitrate reductase activities, were incapable of restoring the nadph-nitrate reductase activity of the mutant nit-1 of neurospora crassa, whereas wild type cells and mutants 203 and 305 had xanthine dehydrogenase and were able to reconstitute the nitrate reductase activi ...198124276829
characterization of a variant neurospora crassa mitochondrial dna which contains tandem reiterations of a 1.9 kb sequence.we have identified a second variant of neurospora mtdna which contains tandem, head-to-tail repeats of sequences at the boundary of eco ri-4 and 6. this region may contain a. major replication origin of neurospora mtdna.198124185958
cell-biology of ageing. 1. isolation of gamma-ray induced ageing mutants of neurospora crassa and their preliminary characterizations. 19816460560
cytochrome c oxidase in cytochrome c oxidase-deficient mutant strains of neurospora crassa.three mutant strains of neurospora crassa, previously characterized as cytochrome c oxidase deficient, were found to possess this respiratory enzyme. the mitochondrial cytochrome contents of logarithmic phase cells of wild type (74a) and the respiration-deficient strains mi-3, cya-4-23, and cya-5-34 were investigated with low temperature difference spectrophotometry; two of the strains were found to possess cytochrome a. cytochrome c oxidase catalytic activity measurements performed on isolated ...19816270105
the involvement of proteolysis in conformational stability of the carbamoyl-phosphate synthetase/aspartate carbamoyltransferase enzyme of neurospora crassa.the pyrimidine-3 gene of neurospora crassa codes for a bifunctional enzyme catalysing the first two steps of the pyrimidine biosynthetic pathway. difficulties have been experienced in purification due to the lability of the enzyme. the enzyme loses carbamoyl-phosphate synthetase (carbon-dioxide: ammonia ligase (adp-forming, carbamate-phosphorylating), ec activity and undergoes a change in apparent molecular weight from the native 650,000 to 100,000 of the only detectable fragment. atte ...19816457644
purification & characterization of two forms of 5'amp nucleotidase form neurospora crassa. 19816273305
cold-sensitive mutation in neurospora crassa affecting the production of 17s ribosomal rna from ribosomal precursor rna.the cold-sensitive mutant strain of neurospora crassa, crib-1 (pj30201) has a conditional defect in ribosome biosynthesis. at 10 °c this mutant underproduces the small (37s) ribosomal subunit. experiments were done to study rrna synthesis in crib-1 after a shift from the permissive (25 °c) to the nonpermissive temperature and vice versa. the results showed that the primary cold-sensitive defect in crib-1 is in the function, rather than the synthesis, of a molecule needed for the production of th ...198124185860
photoregulation of the carotenoid biosynthetic pathway in albino and white collar mutants of neurospora crassa.the conversion of isopentenyl pyrophosphate to phytoene in neurospora crassa requires both a soluble and a particulate fraction. soluble and particulate enzyme fractions obtained from light-treated and dark-grown wild type, albino-1, albino-2, albino-3, and white collar-1 strains were mixed in various combinations, and the activity for conversion of [1-(14)c]isopentenyl pyrophosphate to phytoene was assayed. from such experiments it can be concluded that: (a) albino-3 is defective in the soluble ...198116661992
purification of vacuoles from neurospora crassa.the neurospora crassa vacuole, defined by its content of basic amino acids, polyphosphate, protease, phosphatases, and alpha-mannosidase, was purified to near homogeneity. the procedure depends upon homogenization of snail gut enzyme-digested cells in a buffer osmotically stabilized with 1 m sorbitol, differential centrifugation of the extract, and sucrose density gradient centrifugation of the organellar pellet. isopycnic centrifugation of vacuoles in 2.25 m sorbitol-metrizamide density gradien ...19819279392
genetic organization and transcriptional regulation in the qa gene cluster of neurospora crassa.a transcription map of the qa gene cluster of neurospora crassa has been constructed by using cloned dna fragments as hybridization probes. the mrnas encoded in the previously identified qa-2 (3-dehydroquinate hydro-lyase, ec, qa-4 (dehydroshikimate dehydratase), qa-3 (quinate:nad+ 3-oxidoreductase, ec, and qa-1 (regulatory protein) genes have been characterized. in addition, mrnas encoded in two new genes in this cluster (qa-x, qa-y) have been identified. regulation of this ...19816458044
photoreception in neurospora crassa: correlation of reduced light sensitivity with flavin deficiency.the effect of flavin deficiency on blue light responses in neurospora crassa was studied through the use of two riboflavin mutants (rib-1 and rib-2). the photoresponses assayed were the suppression of circadian conidiation, the phase shifting of the circadian conidiation rhythm, and the induction of carotenoid synthesis. flavin deficiency was induced in the rib-1 mutant by restrictive growth temperatures and in the rib-2 mutant by low levels of supplemental riboflavin. at 26 degrees c, a semires ...19816458042
characterization of 2-aminoisobutyric acid transport in neurospora crassa: a general amino acid permease-specific substrate.we report the characterization of an amino acid 2-aminoisobutyric acid was transported solely by the general amino acid permease and not by the neutral amino acid permease. furthermore, this substrate was not metabolized after transport. the potential for a system-specific nonmetabolizable substrate as a tool in the analysis of amino acid transport and its regulation is discussed.19816456264
mitochondrial biogenesis during fungal spore germination: respiration and cytochrome c oxidase in neurospora crassa.the germination of conidiospores of wild-type neurospora crassa was found to be dependent upon the function of the cytochrome-mediated electron transport pathway. the cyanide-insensitive alternate oxidase did not contribute significantly to the respiration of these germinating spores. the dormant spores contained all of the cytochrome components and a catalytically active cytochrome c oxidase required for the activity of the standard respiratory pathway, and these preserved components were respo ...19816268605
enzymatic synthesis and function of folylpolyglutamates.derivatives of folic acid occur in nature predominantly as poly (gamma-glutamyl) derivatives containing 2-8 glutamate residues. the data regarding the function of these derivatives, and their biosynthesis by eucaryotic and procaryotic folylpolyglutamate synthetases, is reviewed. the most universal functions of folylpolyglutamates appear to be (a) as the actual cofactors in vivo for folate dependent enzymes, (b) as inhibitors of folate dependent enzymes for which they are not substrates, and (c) ...19817027025
identification and characterization of recombinant plasmids carrying the complete qa gene cluster from neurospora crassa including the qa-1+ regulatory gene.the early reactions in the catabolism of quinic acid in neurospora crassa are controlled by at least four genes which are clustered on linkage group vii. three of the loci (qa-2, qa-4, and qa-3) encode enzymes that convert quinic acid to protocatechuic acid. the fourth gene (qa-1) encodes a positive regulatory protein which, in the presence of quinic acid, leads to the de novo synthesis of the other proteins in the qa cluster. this communication describes a series of recombinant plasmids that sp ...19816272290
the purification and molecular properties of the tryptophan-sensitive 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from neurospora crassa.neurospora crassa contains three isoenzymes of 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase, which are inhibited by tyrosine, tryptophan and phenylalanine respectively, and it was estimated that the relative proportions of the total activity were 54%, 14% and 32% respectively. the tryptophan-sensitive isoenzyme was purified to homogeneity as judged by polyacrylamide-gel electrophoresis and ultracentrifugation. the tyrosine-sensitive and phenylalanine-sensitive isoenzymes were only partia ...19816119978
mutational variants of the neurospora crassa nadp-specific glutamate dehydrogenase altered in a conformational equilibrium. 19816273586
a "stopper" mutant of neurospora crassa containing two populations of aberrant mitochondrial dna.[e35], an extranuclear mutant of neurospora crassa has all the phenotypic characteristics of the "stopper" mutants (de vries et al. 1980). in the present work, the mitochondrial dna as well as the mitochondrial translation products are characterized further. the primary mutational event appears to have been the deletion of about 4 kbp from the wild-type genome. moreover, after prolonged vegetative growth the mutant accumulates an 8-μm circular mtdna, which was demonstrated both by electronmicros ...198124190132
cycloheximide-induced phase shifting of circadian clock of neurospora.cycloheximide (chx), an inhibitor of cytosolic (80s) protein synthesis in eucaryotes, causes phase shifts of the circadian clock of neurospora crassa when administered as 4-h pulses to cultures in liquid medium. differential effects of the pulses at different phases of the circadian cycle were observed and plotted as a phase-response curve (prc). nearly all phase shifts observed were phase advances, with maximum sensitivity in the middle of the subjective day. inhibition of protein synthesis by ...19816454353
the effect of essential amino acid deprivation on poly(a) metabolism in neurospora crassa.poly(a) messenger rna was isolated from a methionine auxotroph of neurospora crassa grown to exponential and early stationary phases, and from mycelia deprived of the essential amino aid. the polyadenylate regions were isolated from the mrna preparations by enzymatic digestion and affinity chromatography, and their lengths determined by electrophoresis on 10% acrylamide/90% formamide gels. there was no significant difference in the lengths of the poly(a) regions between exponential and early sta ...19816115674
uracil's uncoupling of the decarboxylation of alpha-ketoglutarate in the thymine 7-hydroxylase reaction of neurospora crassa.highly purified preparations of thymine 7-hydroxylase from neurospora crassa catalyzed the decarboxylation of alpha-ketoglutarate but yielded no hydroxylated product when uracil was substituted for thymine in the standard incubation mixture. although the uracil-dependent decarboxylation was much slower than the coupled reaction, both reactions were similar with respect to the requirement for molecular oxygen, the stoichiometric formation of succinate, and the stimulations effected by fe2+, ascor ...19816453866
ultrastructural cytochemistry of perinucleolar dense spots in heat-treated macroconidia of neurospora crassa.upon heat treatment at 46 degrees c of neurospora macroconidia, numerous dense sports appear around the nucleolus but disappear completely 5 h after shift-down to normal temperature. cytochemical reactions and high-resolution autoradiography after pulse-labeling with tritiated uridine indicate that these dense sports contain rna (perhaps pre-rrna), rnp and other proteins, but no dna.19816456905
evidence for the involvement of a rapidly turning over protease in the degradation of cytochrome oxidase in neurospora crassa. 19816268065
genes in neurospora that suppress recombination when they are heterozygous.genes that suppress recombination when heterozygous have been found distributed as a polymorphism in wild and laboratory populations of neurospora crassa. three alleles, sse, sss and ssc, are associated, respectively, with th the three wild types emerson, st. lawrence 74a and costa rica a. it is proposed that ss (synaptic sequence) genes modulate recombination by determining the pairing closeness of dna duplexes in the vicinity of the nit-2 locus. when heterozygous, ss suppresses recombination 2 ...19816461572
general control of arginine biosynthetic enzymes in neurospora crassa.the response of six amino acid synthetic enzymes, including four concerned with arginine synthesis, one with histidine synthesis and one with lysine synthesis, to conditions of histidine and arginine limitation and to exogenously provided amino acids is described in neurospora crassa. the activities of all these enzymes increased in response to lowered levels of histidine or arginine, but showed little or no repression in wild-type cultures supplemented with casein hydrolysate. the activity of g ...19816459428
membrane-bound and water-soluble cytochrome c1 from neurospora mitochondria.cytochrome c1 is a subunit of ubiquinol--cytochrome c reductase (ec in neurospora crassa wild type 74a grown in the presence of chloramphenicol, the subunit is inserted only into the bilayer of the mitochondrial inner membranes without associating with other proteins. from these modified membranes a monodisperse (cytochrome c1)-triton complex was isolated by subjecting the triton-solubilized membranes to affinity chromatography on immobilized cytochrome c. a water-soluble pentamer of ...19816265210
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
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 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 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
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
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