isolation and characterization of mutants defective in production of laccase in neurospora crassa.a protein synthesis inhibitor, cycloheximide, induces excretion of laccase in neurospora crassa. the lah-1 mutation results in excretion of a large amount of laccase even in the absence of cycloheximide. ten mutations were induced that suppress derepressed excretion of laccase in the lah-1 mutant. of these, seven second-site mutations were found to confer a laccase-noninducible phenotype, and were classified into two different complementation groups. four mutations define a locus designated lni- ...19938102779
cloning, in vitro mitochondrial import and membrane assembly of the 17.8 kda subunit of complex i from neurospora crassa.we have cloned and sequenced a cdna encoding a 17.8 kda subunit of the hydrophobic fragment of complex i from neurospora crassa. the deduced primary structure of this subunit was partially confirmed by automated edman degradation of the isolated polypeptide. the sequence data obtained indicate that the 17.8 kda subunit is made as an extended precursor of 20.8 kda. resistance of the polypeptide to alkaline extraction from mitochondrial membranes and the existence of a putative membrane-spanning d ...19938343129
expression of the open reading frames of a senescence-inducing, linear mitochondrial plasmid of neurospora crassa.senescence-prone strains of neurospora crassa from aarey, india, harbor a linear mitochondrial plasmid, maranhar, which potentially encodes an rna polymerase and a dna polymerase (court and bertrand, 1992). to investigate the expression of the open reading frames (orfs) of this plasmid, the mitochondria of the prototype of the senescence-prone strains, aarey-1e, were analyzed for the presence of maranhar-specific transcripts and proteins. in addition to several low-abundance and small rnas, two ...19938397426
spreading the synaptonemal complex of neurospora crassa.a protocol was developed to spread the synaptonemal complex (sc) of the fungus neurospora crassa. it involves direct mechanical breakage of meiotic cells before spreading. this technique makes it possible to examine the sc of the same nucleus with both light and electron microscopy. this protocol is potentially applicable for other pyrenomycetes. the scs were examined at zygotene, pachytene and diplotene. the central elements and the recombination nodules (rn) were well revealed by silver staini ...19938375215
chromosome rearrangements recovered following transformation of neurospora chromosome rearrangements were found in 10% or more of mitotically stable transformants. this was shown for transformations involving a variety of different markers, vectors and recipient strains. breakpoints were randomly distributed among the seven linkage groups. controls using untransformed protoplasts of the same strains contained almost no rearrangements. a study of molecularly characterized am+ transformants showed that rearrangements are frequent when multiple ectopic integration eve ...19938349106
effects of inositol starvation on the levels of inositol phosphates and inositol lipids in neurospora inositol-requiring strain of neurospora crassa was labelled during growth in liquid medium with [3h]inositol, and the levels of inositol phosphates and phosphoinositides were determined under inositol-sufficient and inositol-starved conditions. because the mutant has an absolute requirement for inositol, the total mass of inositol-containing compounds could be determined. inositol-containing lipids were identified by deacylation and co-migration with standards on h.p.l.c.; ptdins3p, ptdins4p, ...19938391257
evidence against a direct role for inositol phosphate metabolism in the circadian oscillator and the blue-light signal transduction pathway in neurospora crassa.the inositol-depletion hypothesis proposes that the effects of li+ on cellular functions are the result of inhibition by li+ of the inositol monophosphate phosphatase and subsequent depletion of inositol lipids. this mechanism has been proposed to account for the effects of li+ on the period of the circadian oscillator. inositol phosphate metabolism has also been proposed as part of the blue-light signal-transduction pathway through which the phase of the circadian oscillator can be reset by lig ...19938318009
translocation and insertion of precursor proteins into isolated outer membranes of mitochondria.nuclear-encoded proteins destined for mitochondria must cross the outer or both outer and inner membranes to reach their final sub-mitochondrial locations. while the inner membrane can translocate preproteins by itself, it is not known whether the outer membrane also contains an endogenous protein translocation activity which can function independently of the inner membrane. to selectively study the protein transport into and across the outer membrane of neurospora crassa mitochondria, outer mem ...19938389769
genetic control of fungal differentiation: the three sporulation pathways of neurospora crassa.sporulation in the mold neurospora crassa can proceed along three very different pathways, leading to the production of three types of spores. two asexual sporulation pathways that lead to the formation of macroconidia and microconidia involve budding from hyphae by two different mechanisms. a much more complex sexual reproductive pathway involves the formation of a fruiting body called a perithecium, in which meiosis takes place and ascospores are formed in sac-like cells called asci. numerous ...19938357339
the effect of rec-2 on repeat-induced point-mutation (rip) and recombination events that excise dna sequence duplications at the his-3 locus in neurospora neurospora crassa, duplicated dna suffers both extensive repeat-induced point-mutation (rip) and also excision by recombination events during the dikaryotic phase of the life cycle that precedes karyogamy and meiosis (reviewed by selker 1990). this paper describes experiments designed to test the effect of rec-2, a gene known to modulate the local level of meiotic recombination at his-3, on rip and the excision of tandem duplications. duplications carrying his-3 sequences and a marker, hygr, ...20068319308
the 12.3 kda subunit of complex i (respiratory-chain nadh dehydrogenase) from neurospora crassa: cdna cloning and chromosomal mapping of the gene.the 12.3 kda subunit of complex i (respiratory-chain nadh dehydrogenase) is a nuclear-coded protein of the hydrophobic fragment of the enzyme. we have isolated and sequenced a full-length cdna clone coding for this polypeptide. the deduced protein is 104 amino acid residues long with a molecular mass of 12305 da. this particular subunit of complex i lacks a cleavable mitochondrial targeting sequence. in agreement with its localization within complex i, we have found that this subunit behaves lik ...19938098209
molecular characterization of conventional and new repeat-induced mutants of nit-3, the structural gene that encodes nitrate reductase in neurospora crassa.nitrate reductase of neurospora crassa is a dimeric protein composed of two identical subunits, each possessing three separate domains, with flavin, heme, and molybdenum-containing cofactors. a number of mutants of nit-3, the structural gene that encodes neurospora nitrate reductase, have been characterized at the molecular level. amber nonsense mutants of nit-3 were found to possess a truncated protein detected by a specific antibody, whereas ssu-1-suppressed nonsense mutants showed restoration ...19938479443
differential effects of anticytoskeletal compounds on the localization and chemical patterns of actin in germinating conidia of neurospora crassa.anti-actin drugs, cytochalasins a and b, inhibited both normal single, and benomyl-induced multiple, germ tube outgrowth from conidia of neurospora crassa. actin was cytochemically found to be concentrated in each of the benomyl-induced germ tube tips. no significant quantitative changes either in total actin or its isoforms were measured in the inhibitor-treated germlings. while intact microtubules are required for normal, monopolar axiation of the germ tube, they appear not to be necessary for ...19938472908
reactive oxygen species associated with cell differentiation in neurospora crassa.the conidiation process of neurospora crassa is characterized by three morphogenetic events: adhesion of hyphae, development of aerial hyphae, and conidia formation. at the onset of all three events a spontaneous, low-level chemiluminescence was detected, indicating the formation of reactive oxygen species. hyperoxic conditions increased chemiluminescence and accelerated differentiation. hypoxic conditions abolished both chemiluminescence and differentiation. chemiluminescence was enhanced by lu ...19938458586
nad(+)-specific glutamate dehydrogenase of neurospora crassa: cloning, complete nucleotide sequence, and gene mapping.the nad(+)-specific glutamate dehydrogenase (nad-gdh) of the filamentous fungus neurospora crassa is a tetrameric enzyme, regulated by catabolite repression. the amino acid sequence of this enzyme had been published several years ago. with the object of investigating the molecular mechanism of catabolite repression, the nucleotide sequence of genomic clones containing the coding region, along with 5'- and 3'-flanking noncoding segments of the nad-gdh transcription unit, was obtained. the gdh str ...20138398079
plasmid diversity in senescent and nonsenescent strains of neurospora.a sample of 171 natural isolates of neurospora crassa and neurospora intermedia was tested for senescence. of these, 28 strains senesced within the duration of the experiment. these senescent strains, together with a selection of nonsenescent strains, were examined for the presence of mitochondrial plasmids. this was done by digesting mitochondrial dna preparations with proteinase k, and running these samples on agarose gels. most of the strains examined, both senescent and nonsenescent, contain ...19938455555
pleiotropic and differential phenotypic expression of two sn (snowflake) mutant alleles of neurospora crassa: analysis in homokaryotic and heterokaryotic cells.mutations sn (snowflake) jl301 and c136, in the centromere region of linkage group i in neurospora crassa, are at 0.6-3.0 map units to the left of the os-4 locus. strains carrying snjl301 produce very short aerial hyphae and only arthroconidia, and do not grow in high salt media. snc136 strains produce aerial hyphae, with abnormally large and rounded blastoconidia, at the top of the agar slant cultures, and revert to wild-type growth in high salt media. studies with forced primary heterokaryons ...19938431953
photoregulated carotenoid biosynthetic genes of neurospora crassa. 19938469151
purification of neurospora crassa cytosolic serine hydroxymethyltransferase. 19938304214
fk506-binding protein of neurospora crassa (ncfkbp) mediates sensitivity to the immunosuppressant fk506; resistant mutants identify two loci.growth of neurospora crassa wild-type is inhibited by micromolar concentrations of the immunosuppressive macrolide fk506. spontaneous and induced mutations that confer resistance to fk506 identified two loci, fkr-1 and fkr-2. they map on the right arm of linkage group v on either side of inl with fkr-1 being centromere proximal. allele fb (fkr-2) lacks immunodetectable n. crassa fk506-binding protein (ncfkbp). this demonstrates that the sensitivity of n. crassa towards fk506 is mediated by ncfkb ...19937679056
isolation and characterization of new fluoroacetate resistant/acetate non-utilizing mutants of neurospora crassa.sixty-two mutants of the filamentous fungus neurospora crassa were isolated on the basis of resistance to the antimetabolite fluoroacetate. of these, 14 were unable to use acetate as sole carbon source (acetate non-utilizers, acu) and were the subject of further genetic and biochemical analysis. these mutants fell into four complementation groups, three of which did not complement any known acu mutants. mutants of complementation group 3 failed to complement acu-8, demonstrated similar phenotypi ...19921362582
induction and intracellular localization of the 80-kilodalton heat-shock protein of neurospora crassa.the most abundant heat-shock protein of neurospora crassa is a multimeric glycoprotein of 80-kilodaltons (i.e., hsp80), induced strongly by hyperthermia and at a lower level by sodium arsenite, ethanol, and carbon source depletion. immunoelectron microscopy, using indirect immunogold labelling demonstrated that hsp80 was undetectable in mycelium cultured at the normal growth temperature of 28 degrees c, but it appeared rapidly following the commencement of heat-shock treatment at 48 degrees c. h ...19921299272
nucleolar dense granules in cytochalasin-treated conidia of neurospora crassa. 19921288898
accumulation of the pre-assembled membrane arm of nadh:ubiquinone oxidoreductase in mitochondria of manganese-limited grown neurospora crassa.the nadh:ubiquinone oxidoreductase (complex i) of mitochondria is constructed from two arms arranged perpendicular to each other. the peripheral arm protruding into the matrix contains the proximal section of the electron pathway, and the membrane arm with all mitochondrially encoded subunits contains the distal section of the electron pathway. when neurospora crassa is grown under manganese limitation the formation of the peripheral arm is disturbed, but the membrane arm containing the iron-sul ...19921330699
vacuolar atpase of neurospora crassa: electron microscopy, gene characterization and gene inactivation/mutation.we are using three approaches to investigate the vacuolar atpase, v-atpase, from neurospora crassa. (1) examination in the electron microscope shows the enzyme has a 'ball and stalk' structure like the f-type atpases. however, the vacuolar atpase is significantly larger, has a prominent cleft in the head sector, and has extra components associated with the stalk and membrane sectors. (2) genes encoding three of the major subunits of the vacuolar atpase and the homologous subunits of the mitochon ...19921491233
length heterogeneity in its 2 and the methylation status of ccgg and gcgc sites in the rrna genes of the genus peronosclerospora.the polymerase chain reaction (pcr) was used with primers complementary to conserved flanking sequences to amplify the internal transcribed spacer 2 (its 2) of the rdna repeat units of five peronoscleropora isolates, one each of p. sorghi, p. maydis, p. sacchari and two of p. zeae. in contrast to the situation found in most-fungi that have been examined, length heterogeneity was evident in each sample. the rdna composition of the amplified bands was confirmed by southern hybridizations using an ...19921423729
genetic organization and structural features of maranhar, a senescence-inducing linear mitochondrial plasmid of neurospora crassa.the nucleotide sequence of maranhar, a senescence-inducing linear mitochondrial plasmid of neurospora crassa, was determined. the termini of the 7-kb plasmid are 349-bp inverted repeats (tirs). each dna strand contains a long open reading frame (orf) which begins within the tir and extends toward the centre of the plasmid. orf-1 codes for a single-subunit rna polymerase that is not closely related to that encoded by another neurospora plasmid, kalilo. the orf-2 product may be a b-type dna polyme ...19921423726
truffle melanogenesis: correlation with reproductive differentiation and ascocarp ripening.the present work uses histochemical techniques to investigate the correlation between reproductive differentiation and age of truffles (tuber aestivum and tuber melanosporum) with melanin synthesis. the dopa oxidase and tyrosine hydroxylase activities of tyrosinase have been localized within the ascocarp and melanin localization was performed by the schmorl's reaction. a true tyrosinase is present in truffles, able to oxidize both l-tyrosine and l-dopa. the tyrosinase activity is on in the young ...19921363133
characterization of assembly intermediates of nadh:ubiquinone oxidoreductase (complex i) accumulated in neurospora mitochondria by gene disruption.nadh:ubiquinone oxidoreductase, the respiratory chain complex i of mitochondria, is an assembly of some 25 nuclear-encoded and 7 mitochondrially encoded subunits. the complex has an overall l-shaped structure formed by a peripheral arm and an elongated membrane arm. the peripheral arm containing one fmn and at least three iron-sulphur clusters constitutes the nadh dehydrogenase segment of the electron pathway. the membrane arm with at least one iron-sulphur cluster constitutes the ubiquinone red ...19921433284
cytology of recessive sexual-phase mutants from wild strains of neurospora crassa.wild-collected strains of neurospora crassa harbor recessive mutations that are expressed in the sexual phase when homozygous. thirty-two representative mutants that produced barren perithecia were examined cytologically. six of these mutants failed to form asci. of the remaining 26, chromosome pairing was disturbed in 12 and meiosis was disturbed at pachytene or diplotene in 5. seven mutants showed normal meiosis i but then diverged from the normal sequence, and two showed perithecial beak abno ...19921427061
a combination inversion and translocation in neurospora crassa with inviable deficiency progeny that can be rescued in heterokaryons.chromosome rearrangement in(il;ir)t(il;iiir)slm-1, has a pericentric inversion in linkage group i associated with a reciprocal translocation between i and iii. the rearrangement was identified cytologically in pairing with normal sequence chromosomes at pachynema. rearrangement breakpoints were mapped genetically in il, ir and iiir by crosses with normal sequence strains and in crosses with an inversion that partially overlaps the slm-1 inversion. when rearrangement slm-1 is crossed to parents w ...19921427036
[in situ studies of myoinositol-1-p synthase in wild and inos- strains of neurospora crassa].the biosynthetic pathway for myo-inositol consist of two enzymatic steps: first, the cycloaldolization of glucose-6p to l-myo-inositol-ip followed by its hydrolysis to form free myo-inositol. the former reaction is catalyzed by myo-inositol-ip synthase (mips) while, a phosphatase is responsible for the hydrolysis step. depending on its degree of purification and storage age, mips activity us to be, from partial to fully, dependent on added nad. therefore, we decided to study the kinetic properti ...20131345122
de novo synthesis and desaturation of fatty acids at the mitochondrial acyl-carrier protein, a subunit of nadh:ubiquinone oxidoreductase in neurospora crassa.we have cultivated the cel mutant of neurospora crassa defective in cytosolic fatty acid synthesis with [2-14c]malonate and found radioactivity covalently attached to the mitochondrial acyl-carrier protein (acp), a subunit of the respiratory chain nadh:ubiquinone oxidoreductase. we purified the acp by reverse-phase hplc: the bound acyl groups were trans-esterified to methylesters and analyzed by gas chromatography. the saturated c6 to c18 fatty acids and oleic acid were detected. de novo synthes ...19921397269
structure of the vacuolar atpase from neurospora crassa as determined by electron microscopy.we have examined the structure of the vacuolar atpase of neurospora crassa using negatively stained preparations of vacuolar membranes and of detergent-solubilized and gradient-purified atpase complexes. we also examined the peripheral sector (v1) of the enzyme after it had been removed and purified. using different stains, vacuolar membranes displayed ball-and-stalk structures similar to those of the intact mitochondrial atpase. however, the vacuolar atpase was clearly different from the mitoch ...19921388158
probing the structure of the neurospora crassa plasma membrane h(+)-atpase.the structure of the neurospora crassa plasma membrane h(+)-atpase has been investigated using a variety of chemical and physiochemical techniques. the transmembrane topography of the h(+)-atpase has been elucidated by a direct, protein chemical approach. reconstituted proteoliposomes containing purified h(+)-atpase molecules oriented predominantly with their cytoplasmic surface facing outward were treated with trypsin, and the numerous peptides released were purified by hplc and subjected to am ...19921461258
isolation of neurospora crassa a mating type mutants by repeat induced point (rip) the filamentous fungus, neurospora crassa, mating type is regulated by a single locus with alternate alleles, termed a and a. the mating type alleles control entry into the sexual cycle, but during vegetative growth they function to elicit heterokaryon incompatibility, such that fusion of a and a hypha results in death of cells along the fusion point. previous studies have shown that the a allele consists of 5301 bp and has no similarity to the a allele; it is found as a single copy and only ...19921398049
transformants of neurospora crassa with the nit-4 nitrogen regulatory gene: copy number, growth rate and enzyme activity.nit-4 is a pathway-specific regulatory gene which controls nitrate assimilation in neurospora crassa, and appears to mediate nitrate induction of nitrate and nitrite reductase. the nit4 protein consists of 1090 amino-acid residues and possesses a single gal4-like putative dna-binding domain plus acidic, glutamine-rich, and polyglutamine regions. several mutants with amino-acid substitutions in the putative dna-binding domain and a nit-4 deletion mutant, which encodes a truncated nit4 protein lac ...19921388109
expression of neurospora crassa laccase under the control of the copper-inducible metallothionein-promoter.laccase from the ascomycete neurospora crassa is an inducible secretory enzyme. in vegetatively growing cultures its biosynthesis is repressed but can be induced by different protein synthesis inhibitors. transformation of the n. crassa wild-type strain singapore with a fusion gene consisting of the n. crassa copper-metallothionein promoter and the laccase gene are described in this report. correct integration of the 3.6 kilobase (kb) promoter-fragment fused with the laccase gene containing a 5' ...19921388108
sexual development genes of neurospora crassa.the filamentous fungus neurospora crassa undergoes a complex program of sexual development to form a fruiting body composed of several kinds of specialized tissue. subtractive hybridization was used to isolate genes that are expressed preferentially during this sexual phase. many such sexual development (sdv) genes were identified in a cosmid library of neurospora genomic dna. fourteen of the sdv genes were subcloned, and their expression in mutant strains and under crossing and vegetative growt ...19921356883
photoinduction of albino-3 gene expression in neurospora crassa conidia.the synthesis of carotenoids is induced by blue light in neurospora crassa mycelia, while in conidia (the vegetative spores) the accumulation of carotenoids also occurs in the dark. the expression of the albino-3 (al-3) gene (coding for the carotenogenic enzyme geranyl-geranyl pyrophosphate synthetase) in isolated conidia was analysed. the level of al-3 mrna was shown to be increased in light-induced wild type (wt) conidia. this light response was elicited by blue light and was under the control ...19921453275
electrophoretic profiles of mitochondrial plasmids in neurospora suggest they replicate by a rolling circle mechanism.migratory behaviour of mitochondrial plasmids from neurospora crassa mauriceville-1c and n. intermediate labelle has been studied by pulsed field gel electrophoresis (pfge). electrophoretic profiles demonstrate that long, linear molecules of a heterogeneous size are the prevailing form of plasmid dna in vivo. circular forms represent less than 8-9% of plasmid dna. single stranded dna regions are abundant and lead to electrophoretic inertia of a significant amount of plasmid dna. these profiles i ...19921387311
arginine transport in mitochondria of neurospora crassa.transport of arginine into mitochondria of neurospora crassa has been studied. arginine transport was found to be saturable (km = 6.5 mm) and to have a ph optimum of ph 7.5. mitochondrial arginine transport appeared to be facilitated transport rather than active transport because: (i) the arginine concentration within the mitochondrial matrix after transport was similar to that of the reaction medium, and (ii) uncouplers and substrates of oxidative phosphorylation did not affect the transport ra ...19921386360
the vacuolar atpase of neurospora crassa.the filamentous fungus neurospora crassa has many small vacuoles which, like mammalian lysosomes, contain hydrolytic enzymes. they also store large amounts of phosphate and basic amino acids. to generate an acidic interior and to drive the transport of small molecules, the vacuolar membranes are densely studded with a proton-pumping atpase. the vacuolar atpase is a large enzyme, composed of 8-10 subunits. these subunits are arranged into two sectors, a complex of peripheral subunits called v1 an ...19921400281
timing of synthesis and cellular localization of two conidiation-specific proteins of neurospora crassa.the process of conidiation in neurospora crassa consists of a series of distinct developmental stages culminating in the formation of multinucleate asexual spores called macroconidia. immunoblotting techniques were used to study the timing of synthesis and cellular localization of con10 and con13, the products of two genes that are expressed during conidiation but not during mycelial growth. both proteins first appear about 8 hr into conidiation; con10 disappears between 2 and 4 hr after germina ...19921386581
direct transfer of molybdopterin cofactor to aponitrate reductase from a carrier protein in chlamydomonas reinhardtii.a chlamydomonas reinhardtii molybdenum cofactor (moco)-carrier protein (cp), capable of reconstituting nitrate reductase activity with apoprotein from the neurospora crassa mutant nit-1, was subjected to experiments of diffusion through a dialysis membrane and gel filtration. cp bonded firmly moco and did not release it efficiently unless aponitrate reductase was present in the incubation mixture. stability of moco bound to cp against air and heat was very similar to that of free-moco released f ...19921644169
cytoplasmic location of amino acids 359-440 of the neurospora crassa plasma membrane h(+)-atpase.the topographic location of the region comprising amino acids 359-440 of the neurospora crassa plasma membrane h(+)-atpase has been elucidated using reconstituted proteoliposomes and protein chemical techniques. proteoliposomes containing h(+)-atpase molecules oriented predominantly with their cytoplasmic surface facing outward were cleaved with trypsin and the resulting digest was subjected to centrifugation on a glycerol step gradient to separate the released and liposome-bound peptides. the r ...19921386255
alternative modes of mrna processing in a 3' splice site mutant of neurospora crassa.the am8 mutant of neurospora crassa is shown to have a double base-pair change, gtg for the normal tag, at the 3' end of the second intron of the am (nadp-specific glutamate dehydrogenase, gdh) gene. the greater part of the mutant am transcript accumulates as two fragments hybridising to probes for sequences respectively upstream and downstream of the 5' end of the intron. two processed transcripts approximating to normal full length mrna were identified. in one the second intron was intact; in ...19921535288
ribosomal dna is a site of chromosome breakage in aneuploid strains of wild-type strains of neurospora crassa, the rdna is located at a single site in the genome called the nucleolus organizer region (nor), which forms a terminal segment on linkage group (lg) v. in the quasiterminal translocation strain t(i;v)ar190, most of the right arm of lg i moved to the distal tip of the nor, and one or a few rdna repeat units are moved to the truncated right arm of lg i. i report here that, in partial diploid strains derived from t(i;v)ar190, large terminal deletions resul ...19921385794
molecular cloning of a gene (cfp) encoding the cytoplasmic filament protein p59nc and its genetic relationship to the snowflake locus of neurospora crassa.p59nc is a 59-kd polypeptide associated with 8-10-nm diameter cellular filaments in normal neurospora crassa strains. abnormally sized and shaped bundles of these structures are present in n. crassa strains carrying mutations at the locus sn (snowflake). by using molecular cloning and restriction fragment length polymorphism (rflp) segregation analysis strategies we show here that sn is not the genetic locus of p59nc. several p59nc cdnas were cloned from a n. crassa lambda gt11 library after imm ...19921352758
increase in superoxide production by heat-shocked cells of neurospora crassa, demonstrated by a fluorometric assay.1. increase in superoxide production by heat-shocked cells of neurospora crassa was demonstrated by a fluorometric assay. 2. a sensitive fluorometric assay for the estimation of superoxide anion radical--based on the liberation of 4-methylumbelliferone from 4-methyl-beta-d-umbelliferyl glucopyranoside--is described. 3. using this system the level of superoxide in the medium of heat-shocked neurospora crassa cells was found to be consistently higher, in comparison with that of non-shocked cells, ...19921327889
molecular analysis of the neurospora clock: cloning and characterization of the frequency and period-4 genes.genetic analysis of neurospora crassa has identified many mutants that affect the biological clock. in this article we review the cloning of two of these genes, frq and prd-4. both genes were isolated using a chromosome walk technique. subcloning experiments and subsequent northern analysis of frq implicate the importance of two transcripts that emanate from this locus. in preliminary data, no protein-coding region is evident in the smaller transcript; the larger transcript contains a 962-amino ...19921535290
circadian rhythms in neurospora crassa: the role of metabolism and mitochondria have been discussed with respect to their role in the circadian rhythm mechanism for some time. numerous examples of inhibitors that affect the mitochondria of plants and animals and microorganisms are known, which cause large phase shifts in the rhythms of these organisms. analogous studies on the role of mitochondria in the neurospora circadian rhythm mechanism have also been reported and summarized. this communication differs from previous studies on other o ...19921535289
cot-1, a gene required for hyphal elongation in neurospora crassa, encodes a protein kinase.neurospora crassa is a filamentous fungus that grows on semisolid media by forming spreading colonies. mutations at several loci prevent this spreading growth. cot-1 is a temperature sensitive mutant of n.crassa that exhibits restricted colonial growth. at temperatures above 32 degrees c colonies are compact while at lower temperatures growth is indistinguishable from that of the wild type. restricted colonial growth is due to a defect in hyphal tip elongation and a concomitant increase in hypha ...19921534751
expression of con genes along the three sporulation pathways of neurospora crassa.the filamentous fungus neurospora crassa produces three types of spores by using different developmental pathways: macroconidiation, microconidiation, and sexual spore (ascospore) formation. several genes of unknown function have been cloned by virtue of their expression during macroconidiation but not during mycelial growth (con genes). it had been postulated that expression of the con genes was specific to macroconidiation. to test this assumption, protein extracts from macroconidia, microconi ...19921534304
the basis of decreased recombination in certain outcrosses of neurospora crassa.crossing over in a multiply marked segment of linkage group i was conspicuously reduced in outcrosses between a marked laboratory strain and each of six unrelated wild-collected strains, compared with crosses between inbred laboratory strains. the marked chromosome segment was transferred intact from the inbred strain to one of the wild-collected strains by seven recurrent backcrosses, and conversely, the corresponding segment of the wild strain was transferred to the inbred background by backcr ...19921385584
use of gene replacement transformation to elucidate gene function in the qa gene cluster of neurospora crassa.gene replacement by transformation, employing selective genetic recombination techniques, has been used to delete or disrupt the qa-x, qa-y and qa-1s genes of the qa gene cluster of neurospora crassa. the growth characteristics of the strain carrying the deletion of the qa-y gene support earlier evidence that this gene encodes a quinic acid permease. the strain containing the deletion of the qa-1s gene (delta qa-1s) was examined with respect to quinic acid induction and carbon catabolite repress ...19921533844
a single amino-acid substitution in the beta-tubulin gene of neurospora confers both carbendazim resistance and diethofencarb sensitivity.two mbc-resistant mutants of neurospora crassa, f914 and f939, were sensitive to diethofencarb at a concentration of 0.1 micrograms/ml, while the wild-type strain and other mbc-resistant mutants showed resistance to diethofencarb at a concentration of 100 micrograms/ml. genetic analysis suggested that the mutations in these two strain were closely linked to the bml locus which codes for beta-tubulin. when the wild-type strain was transformed by the cloned beta-tubulin gene of the f914 strain, th ...19921388107
molecular analysis of the laccase gene from the chestnut blight fungus and selective suppression of its expression in an isogenic hypovirulent strain.the gene encoding laccase in the chestnut blight fungus, cryphonectria parasitica, has been cloned and characterized. the predicted c. parasitica laccase amino acid sequence (591 aa) was 57% identical to the neurospora crassa laccase sequence and contained four potential copper-binding regions that are conserved in a number of copper-binding proteins. treatment of a virulent c. parasitica strain with 3 microm cycloheximide resulted in a marked increase in laccase mrna accumulation, whereas ident ...20081535523
bioelectrorheological model of the cell. 3. viscoelastic shear deformation of the analytical electromechanical model of a spherical cell exposed to an alternating electric field was used to calculate shear stress generated in the cellular membrane. shape deformation of neurospora crassa (slime) spheroplasts was measured. statistical analysis permitted empirical evaluation of creep of the cellular membrane within the range of infinitesimal stress. final results were discussed in terms of various rheological models.19921387010
sequence and characterization of the met-7 gene of neurospora crassa.the proteins encoded by the met-7+ and met-3+ genes of neurospora crassa are required to form a functional cystathionine-gamma-synthase (cgs). the met-7+ gene has been cloned by complementation of a met-7 mutant. the nucleotide sequence of the complementing dna reveals the presence of a 542-amino acid open reading frame (orf). disruption of this orf abolishes complementation of the met-7 mutation.19921531800
binding of a synthetic targeting peptide to a mitochondrial channel protein.membrane crystals of the mitochondrial outer membrane channel vdac (porin) from neurospora crassa were incubated with a 20-amino-acid synthetic peptide corresponding to the n-terminal targeting region of subunit iv of cytochrome oxidase. the peptide caused disordering and contraction of the crystal lattice of the membrane arrays. also, new stain-excluding features were observed on the peptide-treated arrays which most likely correspond to sites at which the peptide accumulates. the stain exclusi ...19921380505
a soluble mitochondrial protein increases the voltage dependence of the mitochondrial channel, vdac.a soluble protein isolated from mitochondria has been found to modulate the voltage-dependent properties of the mitochondrial outer membrane channel, vdac. this protein, called the vdac modulator, was first found in neurospora crassa and then discovered in species from other eukaryotic kingdoms. the modulator-containing fraction (at a crude protein concentration of 20 micrograms/ml) increases the voltage dependence of vdac channels over 2-3-fold. at higher protein concentrations (50-100 microgra ...19921380504
import of cytochrome c heme lyase into mitochondria: a novel pathway into the intermembrane space.cytochrome c heme lyase (cchl) catalyses the covalent attachment of the heme group to apocytochrome c during its import into mitochondria. the enzyme is membrane-associated and is located within the intermembrane space. the precursor of cchl synthesized in vitro was efficiently translocated into isolated mitochondria from neurospora crassa. the imported cchl, like the native protein, was correctly localized to the intermembrane space, where it was membrane-bound. as with the majority of mitochon ...19921371459
the pho-2a mutant of neurospora crassa which is deficient in pi-repressible alkaline phosphatase (ec is also defective in pi-repressible acid phosphatase (ec the mycelial pi-repressible acid phosphatase presented p-nitrophenylphosphatase activity with negative cooperativity and michaelian behavior when synthesized by the wild-type and pho-2a mutant strains of neurospora crassa, respectively. 2. the major acid phosphatase present in cell extracts of the pho-2a mutant of n. crassa grown in low pi medium is more thermolabile (t1/2 = 4 min at 54 degrees c, ph 5.4) than that of the wild strain (stable for at least 80 min at 54 degrees c, ph 5.4). 3. th ...19921342219
effects of light on protein secretion in neurospora crassa.the relative concentrations of secreted proteins in liquid cultures of neurospora crassa differ in constant darkness compared to constant light (2500 lx). light reduces the concentrations of some polypeptides markedly and increases the concentrations of protein species of 67, 40, 18 and 13 kda. the "blind" wc-2 mutant of neurospora does not show light dependent differences in amounts of secreted proteins. one of the light-sensitive extracellular proteins is shown to be a protease of 17.5 kda.19921532303
molecular characterization of mutations of nit-4, the pathway-specific regulatory gene which controls nitrate assimilation in neurospora crassa.the nit-4 genes of three conventional neurospora crassa mutations and of the closely related species, neurospora intermedia, have been isolated by amplifying the genomic dna with the polymerase chain reaction. nucleotide sequencing has revealed that the three nit-4 mutants, alleles 15, 1214, and 2994, are the result of a missense mutation, a nonsense mutation and a frameshift mutation, respectively. the nucleotide sequence of the nit4 protein coding region of a nit-4 mutant (allele 2994) and of ...19921531376
nit2, the nitrogen regulatory protein of neurospora crassa, binds upstream of nia, the tomato nitrate reductase gene, in vitro.the nit-2 gene of neurospora crassa encodes a trans-acting regulatory protein that activates the expression of a number of structural genes which code for nitrogen catabolic enzymes, including nitrate reductase. the nit2 protein contains a cys2/cys2-type zinc-finger dna-binding domain that recognizes promoter regions of the neurospora nitrogen-related genes. the nit2 zinc-finger domain/beta-gal fusion protein was shown to recognize and bind in a specific manner to two upstream fragments of the n ...19921531184
light and the recovery from heat shock induce the synthesis of 38 kda mitochondrial proteins in neurospora crassa.the effect of light on the protein synthesis pattern in the mitochondria of neurospora crassa was examined by in vivo labelling with [35s]-methionine and two-dimensional gel electrophoresis. a brief 5-min illumination induced the rapid and transient synthesis of a 38-kda protein. white collar-mutants were not stimulated to synthesize this protein by light. a protein of a similar molecular weight and isoelectrical point was synthesized during recovery from heat shock.19921444714
phospholipid content of untreated and insulin treated cells of neurospora crassa (wall-less strain).phosphatidylcholine (51.2%) and phosphatidyl-ethanolamine (38.3%) are the most abundant phospholipids in the wall-less strain of neurospora crassa. insulin treatment exerted no change on the amount of phosphoinositides, although some previous results proved the existence of specific insulin receptors and specific effect of insulin on glucose metabolism in these cells. long (20 h) treatment with insulin also failed to cause biologically significant changes.19921343935
blue light induction of conidiation-specific genes in neurospora crassa.the con genes of neurospora crassa are preferentially expressed during a developmental process known as conidiation. we present evidence indicating that transcription of con-5 and con-10 is also stimulated by blue light. transcription of these genes was not photoinducible in wc-1 and wc-2 mutant strains. the response of con-5 and con-10 to blue light was similar to that of al-1 and al-2, genes involved in carotenoid biosynthesis, and bli-3 and bli-4, blue light inducible genes.19911837079
adp-glucose transport by the chloroplast adenylate translocator is linked to starch organello starch biosynthesis was studied using intact chloroplasts isolated from spinach leaves (spinacia oleracea). immunoblot analysis using a specific antiserum against the mitochondrial adenylate (adp/atp) translocator of neurospora crassa shows the presence of an adenylate translocator protein in the chloroplast envelope membranes, similar to that existing in mitochondria and amyloplasts from cultured cells of sycamore (acer pseudoplatanus). the double silicone oil layer-filtering centr ...199116668585
a preproinsulin-like pseudogene from neurospora crassa.a segment of dna was amplified from the neurospora crassa genome by the polymerase chain reaction using several oligonucleotides coding for highly conserved domains in proinsulin as primers and probe. a genomic clone corresponding to this segment was isolated and the nucleotide sequence was determined. the deduced amino acid sequence of a part of this segment bears remarkable resemblance to preproinsulin, but lacks several requirements for transcription or translation and must therefore be consi ...19911838993
efficient dna pairing in a neurospora mutant defective in chromosome pairing.a neurospora crassa mutation, mei-2, affecting recombination and pairing of homologous chromosomes during meiosis, was characterized for its effect on repeat-induced point mutation (rip). we found that rip, which depends on recognition of dna sequence homology, is not inhibited by mei-2, suggesting that the defect in chromosome pairing of this mutant is not due to a defect in dna pairing and that dna pairing is not dependent on chromosome pairing.19911836526
mei-2, a mutagen-sensitive mutant of neurospora defective in chromosome pairing and meiotic recombination.a neurospora crassa mutation, mei-2, affecting meiosis and mutagen sensitivity, was characterized for its effect on meiotic recombination and chromosome pairing. results from homozygous mei-2 crosses involving distant markers on the same chromosome demonstrated a drastic reduction in meiotic recombination. however, mitotic recombination continued to occur. cytological observations indicated that pairing of homologous chromosomes in zygotene was greatly reduced or absent, resulting in aberrant se ...19911836525
regulation of laccase biosynthesis in the plant-pathogenic fungus cryphonectria parasitica by double-stranded rna.transmissible hypovirulence of the chestnut blight fungus, cryphonectria parasitica, is associated with cytoplasmic double-stranded-rna (dsrna) viruses. the fungal laccase has attracted interest because its activity is reduced in hypovirulent dsrna-containing strains. a laccase cdna clone was isolated by screening a cdna expression library with antibodies against the purified extracellular laccase. the amino acid sequence deduced from part of the cdna clone revealed high homology to other fungal ...19911744058
comparative studies of the quinic acid (qa) cluster in several neurospora species with special emphasis on the qa-x-qa-2 intergenic region.the organization of the quinic acid (qa) genes in neurospora crassa has been compared to that in several other neurospora species. this gene cluster was found to be highly conserved in all species examined. however, there are numberous restriction fragment length polymorphisms that distinguish the heterothallic and homothallic species. catabolic dehydroquinase assays indicated that qa-2 gene expression in the homothallic species is subject to induction by quinic acid, as is the case in n. crassa ...19911685010
identification of a sterol mutant of neurospora crassa deficient in delta 14,15-reductase activity.a mutant (erg-3) of neurospora crassa resistant to the polyene antibiotic nystatin was compared with its sensitive, wild-type parent to detect differences in sterol composition using gas chromatography-mass spectrometry. the major sterol in wild-type mycelia, comprising 80% of the total, was ergosterol. the major sterols in mutant mycelia, comprising 86% of the total, were delta 8,14-sterols. it is proposed that the nystatin-resistant strain is unable to synthesize ergosterol because it lacks de ...19911838392
photoregulation of the albino-3 gene in neurospora this paper we describe the light-regulated expression of albino-3 (al-3), a carotenoid biosynthetic gene of neurospora crassa, in the wild-type strain. our results suggest that the al-3 gene expression is regulated by the transcriptional activation of the gene and the low stability of its mrna. the activation of the al-3 gene does not require protein synthesis to occur. the kinetic analysis of the al-3 mrna reveals that the gene is transiently expressed even in continuous light, suggesting th ...19911837560
developmental expression of genes involved in conidiation and amino acid biosynthesis in neurospora crassa.the levels of transcripts for neurospora crassa genes concerned with cellular and metabolic functions changed dramatically at different stages of asexual development. transcripts for some conidiation-related (con) genes were present at high levels in conidiating cultures and in dormant conidia, but were absent or reduced during mycelial growth. levels of some con transcripts increased transiently during conidial germination, while others disappeared. transcripts for amino acid biosynthetic enzym ...19911834495
the induction and repair of (6-4) photoproducts in neurospora crassa.the (6-4) photoproduct lesion found in dna after uv irradiation is repaired by germinating neurospora crassa conidia. wild-type neurospora removes 80% of the (6-4) photoproduct in approximately 20 min and maximal repair is accomplished by 30 min with approximately 89% of the original lesions removed. mutagen-sensitive neurospora mutants belonging to the established excision repair epistasis group, uvs-2, are not defective in the removal of cyclobutane pyrimidine dimers. furthermore, we find thes ...19911719392
an apparent rare-codon effect on the rate of translation of a neurospora the result of two mutually compensating frameshift mutations, three successive codons with third-position a were generated in the neurospora crassa am (nadp-specific glutamate dehydrogenase: gdh) gene. these codons do not occur at all elsewhere in the gene and only infrequently in other highly expressed neurospora genes. the double-frameshift strain produces only 25 to 35% of the normal level of gdh, whether measured as enzyme activity or as immunoprecipitable protein, but its level of gdh mr ...19911834852
electron microscopic analysis of the peripheral and membrane parts of mitochondrial nadh dehydrogenase (complex i).two related forms of the respiratory chain nadh dehydrogenase (nadh:ubiquinone reductase or complex i) are synthesized in the mitochondria of neurospora crassa. normally growing cells make a large form that consists of 25 subunits encoded by nuclear dna and six to seven subunits encoded by mitochondrial dna. cells grown in the presence of chloramphenicol, however, make a smaller form comprising only 13 subunits, all encoded by nuclear dna. when the large enzyme is dissected by chaotropic agents ...19911834851
stability of chitin synthetase in cell-free preparations of a wild-type strain and a 'slime' variant of neurospora crassa.chitin synthetase activity in cell-free preparations from a wild-type strain and a 'slime' variant of neurospora crassa was monitored over many days in samples stored at 0 degrees c. total activity in whole-cell-free extracts and low-speed supernatants from both organisms was very unstable, losing more than 90% of the initial activity on storage at 0 degrees c for 96 h. chitin synthetase detection was not masked by chitinase activity present in the preparations. gel-filtration chromatography of ...19911838089
molecular comparison of the negative-acting nitrogen control gene, nmr, in neurospora crassa and other neurospora and fungal neurospora crassa, the expression of unlinked structural genes which encode nitrogen catabolic enzymes is subject to genetic and metabolic regulation. the negative-acting nmr regulatory gene appears to play a role in nitrogen catabolite repression. using the n. crassa nmr gene as a probe, homologous sequences were identified in a variety of other filamentous fungi. the polymerase chain reaction was used to isolate the nmr-like gene from the exotic mauriceville strain of n. crassa and from the ...19911663340
microcycle conidiation and its genetic basis in neurospora crassa.some wild isolates of neurospora show microcycle conidiation in liquid culture under continuous agitation. macroconidia from agar-grown mycelial cultures germinated in liquid and the germlings spontaneously produced conidia with no intervening mycelial phase. three types of microcycle conidiation were seen among progeny of n. crassa vickramam a x n. crassa a wild-type: (1) multinucleate blastoconidia produced by apical budding and septation, (2) multinucleate arthroconidia produced by holothalli ...19911836224
generation of new mutants of nmr, the negative-acting nitrogen regulatory gene of neurospora crassa, by repeat induced mutation.the repeat induced point mutation (rip) phenomenon has been used to generate new mutants of nmr, the negative nitrogen regulatory gene in neurospora crassa. the wild-type nmr gene was cotransformed along with the hygromycin b resistance gene into wild-type cells by selecting for hygromycin b resistance. following purification of primary transformants using microconidia, many chlorate-sensitive progeny were obtained from crosses to wild-type. detailed analyses of some of the progeny revealed that ...19911834354
the acyl-carrier protein in neurospora crassa mitochondria is a subunit of nadh:ubiquinone reductase (complex i).we determined the primary structure of a 9.6-kda subunit of the respiratory chain nadh:ubiquinone reductase (complex i) from neurospora crassa mitochondria and found a close relationship between this subunit and the bacterial or chloroplast acyl-carrier protein. the degree of sequence identity amounts to 80% in a region of 19 residues around the serine to which the phosphopantetheine is bound. the n-terminal presequence of the subunit has the characteristic features of a mitochondrial import seq ...19911832379
identification of the membrane-embedded regions of the neurospora crassa plasma membrane h(+)-atpase.reconstituted proteoliposomes containing functional neurospora crassa plasma membrane h(+)-atpase molecules oriented predominantly with their cytoplasmic surface exposed were treated with trypsin and then subjected to sepharose cl-6b column chromatography to remove the liberated peptides. the peptides remaining associated with the liposomes were then separated from the phospholipid by sephadex lh-60 column chromatography and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. ...19911830591
sequence and structure of mtr, an amino acid transport gene of neurospora crassa.the gene product of the mtr locus of neurospora crassa is required for the transport of neutral aliphatic and aromatic amino acids via the n system. we have previously cloned three cosmids containing neurospora dna that complement the mtr-6(r) mutant allele. the cloned dnas were tightly linked to restriction fragment length polymorphisms that flank the mtr locus. a 2.9-kbp fragment from one cosmid was subcloned and found to complement the mtr-6(r) allele. here we report the sequence of the fragm ...19911838345
rip (repeat induced point mutation) as a tool in the analysis of p-450 and sterol biosynthesis in neurospora crassa. 19911838342
pectinase production by neurospora crassa: purification and biochemical characterization of extracellular polygalacturonase activity.the production of pectinase was studied in neurospora crassa, using the hyperproducer mutant exo-1, which synthesized and secreted five to six times more enzyme than the wild-type. polygalacturonase, pectin lyase and pectate lyase were induced by pectin, and this induction was glucose-repressible. polygalacturonase was induced by galactose four times more efficiently than by pectin; in contrast the activity of lyases was not affected by galactose. the inducing effect of galactose on polygalactur ...19911835496
a novel phenotype of an excision-repair mutant in neurospora crassa: mutagen sensitivity of the mus-18 mutant is specific to uv.a uv-sensitive mutant has been isolated from uv-mutagenized conidia of neurospora crassa. the mutation responsible for the lesion was mapped in linkage group vl, proximal to the nucleolus organizer region. we designated the mutant mus-18. the sensitivity of the mus-18 mutant to uv-irradiation was not particularly high, being less than twice that of the wild-type strain. however, the frequency of mutations at the ad-3 loci induced by uv was extremely high even at low doses, under conditions where ...19911832207
primary structure of the nuclear-encoded 18.3 kda subunit of nadh: ubiquinone reductase (complex i) from neurospora crassa mitochondria.the primary structure of the nuclear-encoded 18.3 kda subunit of the respiratory chain nadh: ubiquinone reductase (complex i) from neurospora crassa was determined by sequencing cdna and the n-terminus of the protein. the cdna contains an open reading frame for a protein of 206 amino acids. the mature protein consists of 173 amino acids and has a molar mass of 18,341 da. the precursor protein includes a characteristic mitochondrial import sequence with a typical matrix peptidase processing site.19911830490
primary structure of the nuclear-encoded 29.9 kda subunit of nadh: ubiquinone reductase from neurospora crassa mitochondria.we isolated and sequenced cdna for the 29.9 kda subunit of mitochondrial nadh: ubiquinone reductase (complex i) from a neurospora crassa library in the lambda gt11 expression vector. the n-terminus of the mature protein was determined by edman-degradation. the cdna contains an open reading frame encoding a preprotein of 273 amino acids. the presequence of the transit protein essential for mitochondrial import is eight residues long. northern-blot analysis shows, that the level of the correspondi ...19911830489
inhibition of neurospora crassa cytosolic chitinase by allosamidin.a cytosolic chitinase (20 kda by sds-page) was partially purified from neurospora crassa. linear kinetics for enzyme activity were obtained using the substrate [3h]-labelled regenerated chitin, the preparation yielding an apparent km of 0.965 mg ml-1 and a vmax of 3.83 micrograms glcnac min-1 (mg protein)-1. the enzyme was highly sensitive to allosamidin, an inhibitor of insect chitinase, exhibiting an ic50 of 1.6 microm. unlike other chitinases that are inhibited by allosamidin, the mode of inh ...19911834520
beta-oxidation system of the filamentous fungus neurospora crassa. structural characterization of the trifunctional protein.treatment of the trifunctional protein from neurospora crassa with various proteases produced almost identical patterns of proteolytic fragments. to study the structural features of the protein in more detail limited proteolysis with trypsin was carried out. polyclonal antibodies were raised against three different tryptic fragments. with the help of immunological methods and amino-terminal sequence analysis we were able to monitor the sequential cleavage steps during proteolysis. two major frag ...19911830049
a new cyclitol derivative influences inositol metabolism in neurospora crassa.cyclitol derivatives have been synthesized and screened for growth inhibitory effect upon prokaryotic and eukaryotic organisms. one derivative, (2s,3r,5r)-3-azido-2-benzoyloxy-5-hydroxycyclohexanone, was studied in detail: it has no effect upon bacteria, but it is inhibitory to neurospora crassa. in neurospora crassa it increased the amount of myo-inositol-1-phosphate synthase and inhibited the activity of myo-inositol-monophosphatase. the enhanced synthesis of myo-inositol-1-phosphate synthase ...19911657695
the respiratory response to heat shock in neurospora crassa.a sharp decrease in oxygen uptake occurred in neurospora crassa cells that were transferred from 30 degrees c to 45 degrees c, and the respiration that resumed later at 45 degrees c was cyanide-insensitive. energization of mitochondria, measured in vivo with fluorescence microscopy and a carbocyanine dye, also declined sharply in cells at 45 degrees c. electron microscopy showed no changes in mitochondrial complexity; however, the cytoplasm of heat-shocked cells was deficient in glycogen granule ...19911833266
patch clamping vdac in liposomes containing whole mitochondrial membranes.whole mitochondrial membranes isolated from neurospora crassa were reconstituted into liposomes and patch clamped. clear activity characteristic of the mitochondrial channel vdac was found, namely: open state conductance of 650 ps (in 150 mm kcl, 1 mm cacl2, 20 mm hepes, ph 7.2), voltage-dependent closure at both positive and negative potentials, change in conductance upon channel closure of about 450 ps in response to negative and positive potentials, and increased voltage dependence in the pre ...19911723104
alteration of the cytochrome c oxidase subunit 2 gene in the [exn-5] mutant of neurospora crassa.the maternally inherited [exn-5] mutant of neurospora crassa is characterized by its slow-growth rate and deficiency of cytochrome aa3 relative to wild-type strains. we have determined the dna sequence of the coxi and coxii genes of the mutant, which encode subunits 1 and 2 of cytochrome c oxidase, respectively. no changes in the dna sequence of the coxi gene relative to the corresponding wild-type gene were found. in the region of the coxii gene we found two alterations, one a c to t transition ...19911657411
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