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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
photoregulated carotenoid biosynthetic genes of neurospora crassa. 19938469151
molecular cloning of a cdna encoding calmodulin from neurospora crassa.a full-length cdna encoding neurospora crassa calmodulin was isolated from a lambda zap ii cdna expression library. the open reading frame encodes a protein of 148 amino acid residues with a calculated m(r) of 16,865 da. using site-directed mutagenesis, the complete cdna was ligated into a trc promoter-regulated bacterial expression vector to allow expression of n. crassa calmodulin in e. coli. the expressed protein was found to be identical to the native protein on the basis of some of its bioc ...19938467912
isolation, sequencing, and characterization of crp-5, a gene encoding a neurospora ribosomal protein.a neurospora crassa cytoplasmic ribosomal protein gene, crp-5, has been isolated and characterized. the cdna was isolated by a differential screening of a cdna library for glucose-inducible genes. the cdna was subsequently used to identify and isolate crp-5 genomic sequences. computer analysis of the dna sequences showed that they contain an open reading frame which encodes a protein homologous to the rat ribosomal protein s26. the crp-5 mrna levels are regulated in a carbon-source-dependent man ...19938467530
peptide splicing in the vacuolar atpase subunit a from candida tropicalis.subunit a of the vacuolar proton pump appears to be responsible for the atp hydrolysis which is coupled to the pumping of protons into a variety of intracellular acid compartments, including the fungal vacuole. we report here the cloning and sequence determination of the gene encoding subunit a from candida tropicalis. southern blot hybridization analysis indicates that there is a single gene which encodes this protein. the gene contains a single intron at the extreme 5'-end of the coding region ...19938463270
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
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
primary structure of the nuclear-encoded 10.5 kda subunit of complex i from neurospora crassa.we have isolated a cdna clone for the nuclear encoded 10.5 kda subunit of complex i from n. crassa. dna sequencing revealed an open reading frame corresponding to a polypeptide with 94 amino acids and a calculated molecular mass of 10531 da. the protein is synthesized without a cleavable mitochondrial targeting sequence. the n. crassa polypeptide is the fungal equivalent of subunit b8 of bovine complex i.19938448210
the mitochondrial genome of the entomopathogenic fungus beauveria bassiana: analysis of the ribosomal rna region.the 28.5-kbp mitochondrial (mt) genome from the entomopathogenic fungus beauveria bassiana was studied using restriction enzyme analysis, gene probe hybridization, and dna sequence comparisons. a detailed restriction enzyme map allowed cloning of the entire genome into a number of segments. hybridization of heterologous gene probes to the mtdna resulted in the identification of the large ribosomal rna (lrrna) and small ribosomal rna (srrna) genes. gene probes derived from several yeasts and fung ...19938439871
insertional mutagenesis in neurospora crassa: cloning and molecular analysis of the preg+ gene controlling the activity of the transcriptional activator nuc-1.the transcriptional activator nuc-1 controls the transcription of the genes for phosphorus acquisition enzymes, and its activity is regulated by the negative regulatory factors, preg and pgov in this report, we describe the cloning and molecular analysis of the preg+ gene. in neurospora crassa, as in higher eukaryotes, transformation frequently results in nonhomologous integration of transforming dna. insertion of transforming dna into host genes mutates the gene and provides a molecular tag for ...19938436269
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
molecular cloning of the smaller subunit(p52) of rat liver mitochondrial processing protease.a cdna encoding the smaller subunit (p52) of mitochondrial processing protease was isolated from a rat liver cdna library, using cdna fragment for yeast mas1 as the probe. the deduced amino acid sequence is highly homologous to those of pep from neurospora crassa and mas1 from saccharomyces cerevisiae. after in vitro transcription and translation, the precursor peptide was imported into isolated rat liver mitochondria and processed to its mature form.19938422255
hyperactive recombination in the mitochondrial dna of the natural death nuclear mutant of neurospora crassa.in neurospora crassa, a recessive mutant allele of a nuclear gene, nd (natural death), causes rapid degeneration of the mitochondrial dna, a process that is manifested phenotypically as an accelerated form of senescence in growing and stationary mycelia. to examine the mechanisms that are involved in the degradation of the mitochondrial chromosome, several mitochondrial dna restriction fragments unique to the natural-death mutant were cloned and characterized through restriction, hybridization, ...19938413272
a tobacco cdna clone encoding a gata-1 zinc finger protein homologous to regulators of nitrogen metabolism in fungi.in higher plants, the expression of the nitrate assimilation pathway is highly regulated. although the molecular mechanisms involved in this regulation are currently being elucidated, very little is known about the trans-acting factors that allow expression of the nitrate and nitrite reductase genes which code for the first enzymes in the pathway. in the fungus neurospora crassa, nit-2, the major nitrogen regulatory gene, activates the expression of unlinked structural genes that specify nitroge ...19938413186
complete coding sequence, intron/exon organization, and chromosomal location of the gene for the core i protein of human ubiquinol-cytochrome c reductase.core i protein is a nuclear-encoded component of the ubiquinol-cytochrome c reductase complex of the mitochondrial respiratory chain. we have located the gene for the human core i protein in the p21 region of chromosome 3, just upstream of the col7a1 gene which encodes type vii collagen. the core i gene, which has been sequenced in its entirety, is comprised of 10,417 base pairs, from the major transcription start site to the polyadenylation signal, and contains 13 exons. the predicted polypepti ...19938407948
glycogen-bound protein in lower eukaryote and prokaryote.the proteoglycogen fraction of neurospora crassa was purified and subjected to radioiodination with [125i]iodide. amylolysis of the polysaccharide moiety led to the isolation of a labelled 31 kda-protein. the nh2-terminal amino acid sequence of 10 residues of the 31 kda-protein was determined. a 31 kda-protein was also bound to glycogen in escherichia coli. proteoglycogen has not been heretofore found in any primitive unicellular organism.19938401303
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
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
recognition of specific nucleotide bases and cooperative dna binding by the trans-acting nitrogen regulatory protein nit2 of neurospora crassa.the nit2 nitrogen regulatory protein of neurospora is a dna binding protein which contains a single cys2/cys2 type finger motif followed immediately by a highly basic region. several different approaches were employed to identify nucleotides which appear to be in contact with nit2 in the dna-protein complex. methylation interference and missing contact analyses with the promoter dna fragment of the l-amino acid oxidase gene showed that all three purines in both of two gata core sequences and the ...19938396761
multiple isomers of phosphatidyl inositol monophosphate and inositol bis- and trisphosphates from filamentous fungi.the range of inositol phosphates and inositol phospholipids present in three filamentous fungi, neurospora crassa, fusarium graminearum and phanerochaete chrysosporium has been investigated by hplc analysis. the profiles obtained demonstrate that two isomers of phosphatidyl inositol monophosphate are present, and that an apparent complexity in the number of isomers of inositol bis- and trisphosphates is found in filamentous fungi that has not been observed in animal or plant cells.19938394259
effects of inositol starvation on the levels of inositol phosphates and inositol lipids in neurospora crassa.an 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
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
mitochondrial cardiolipin in diverse eukaryotes. comparison of biosynthetic reactions and molecular acyl species.cardiolipin, a unique dimeric phospholipid of bacteria and mitochondria, can be synthesized by two alternative pathways discovered in rat and escherichia coli, respectively. in mitochondrial preparations from fungi (saccharomyces cerevisiae, neurospora crassa), higher plants (phaseolus aureus), molluscs (mytilus edulis) and mammals (rat liver, bovine adrenal gland), cardiolipin was synthesized from cdp-diacylglycerol and phosphatidylglycerol, suggesting a common eukaryotic mechanism of cardiolip ...19938385010
interchangeable associations of calcineurin regulatory subunit isoforms with mammalian and fungal catalytic subunits.two mammalian genes for the ca(2+)-binding regulatory subunit of the calmodulin-dependent protein phosphatase (calcineurin) were identified recently, suggesting unique associations with tissue-specific catalytic subunits. the murine brain (beta 1) and testis (beta 2) isoforms of the regulatory subunit were expressed with poly-histidine carboxyl termini and purified by ni(2+)-chelate chromatography, each exhibiting high affinity ca2+ binding on nitrocellulose overlays. using chromatographic metho ...19938384215
the sta2 and mel1 genes of saccharomyces cerevisiae are idiomorphic.the sta2 (glucoamylase) gene of saccharomyces cerevisiae has been mapped close to the end of the left arm of chromosome ii. meiotic analysis of a cross between a haploid strain containing sta2, and another strain carrying the melibiase gene mel1 (which is known to be at the end of the left arm of chromosome ii) produced parental ditype tetrads only. since there is no significant dna sequence similarity between the sta2 and mel1 genes, or their respective flanking regions, we conclude that these ...19938381338
purification and characterization of the assimilatory nitrate reductase of azotobacter vinelandii.1. a soluble reduced methyl viologen-dependent assimilatory nitrate reductase from azotobacter vinelandii strain uw136 grown aerobically on nitrate was purified to homogeneity by the criteria of nitrate reductase activity staining, and coincidence of a coomassie blue-staining protein band on polyacrylamide gels run under non-denaturing conditions. the specific activity was 3 mumol of no2- formed/min per mg of protein. 2. gel filtration on superose-12 and sds/page showed that the enzyme had an m( ...19938380991
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
day/night and circadian rhythm control of con gene expression in neurospora.in the filamentous fungus neurospora crassa, several events in the process of conidiation are influenced by light. two genes, con-6 and con-10, which were previously shown to be transcriptionally activated during conidiation and by exposure to light, were found to be unexpressed in mycelium maintained in constant darkness or in constant light. however, when mycelium was shifted from darkness to light, transcripts of both genes appeared and were abundant. upon further illumination both transcript ...19938367490
functional domains of the transcriptional activator nuc-1 in neurospora crassa.the nuc-1 regulatory protein directly controls the transcription of these genes and how the activity enzymes in neurospora crassa. to understand how nuc-1 regulates the transcription of these genes and how the activity of nuc-1 is modulated by other regulatory proteins, two putative functional domains of nuc-1 were analysed: the dna-binding domain and the regulatory domain. the dna-binding activity of nuc-1 has not been directly demonstrated; however, results of deletion analysis, sequence analy ...19938359693
the 59-kda polypeptide constituent of 8-10-nm cytoplasmic filaments in neurospora crassa is a pyruvate decarboxylase.the fungus neurospora crassa harbors large amounts of cytoplasmic filaments which are homopolymers of a 59-kda polypeptide (p59nc). we have used molecular cloning, sequencing and enzyme activity measurement strategies to demonstrate that these filaments are made of pyruvate decarboxylase (pdc, ec 4.1.1.1), which is the key enzyme in the glycolytic-fermentative pathway of ethanol production in fungi, and in certain plants and bacteria. immunofluorescence analyses of 8-10-nm filaments, as well as ...19938359692
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
is an activator protein-2-like transcription factor involved in regulating gene expression during nitrogen limitation in fungi?the upstream sequences of all published lignin peroxidase and manganese peroxidase genomic clones from phanerochaete chrysosporium were analyzed. this analysis revealed the presence of putative activator protein-2 (ap-2) recognition sequences in 11 of 15 lignin peroxidase genes. the lignin peroxidase clone glg6 and the manganese peroxidase gene (mnp-1) have two copies of putative ap-2 sequence in the upstream region. interestingly, the lignin peroxidase gene vlg4 of another white rot fungus, tra ...19938357266
nitrate reductase of neurospora crassa: the functional role of individual amino acids in the heme domain as examined by site-directed mutagenesis.the enzyme nitrate reductase, which catalyzes the reduction of nitrate to nitrite, is a multi-redox center homodimeric protein. each polypeptide subunit is approximately 100 kda in size and contains three separate domains, one each for a flavin, a heme-iron, and a molybdopterin cofactor. the heme-iron domain of nitrate reductase has homology with the simple redox protein, cytochrome b5, whose crystal structure was used to predict a three-dimensional structure for the heme domain. two histidine r ...19938355655
cloning of the gene for glutamate decarboxylase and its expression during conidiation in neurospora crassa.neurospora crassa glutamate decarboxylase (gad) is produced during conidiation and stored in dormant conidia. polyclonal antibody was generated to gad that had been purified to homogeneity. the anti-gad antibody was specific for n. crassa gad and inhibited gad activity. the level of gad protein decreased during conidial germination, indicating that gad was degraded during this phase of development. the anti-gad antibody was used to isolate a cdna clone of gad from a lambda zap cdna expression li ...19938352739
functional identification of al-3 from neurospora crassa as the gene for geranylgeranyl pyrophosphate synthase by complementation with crt genes, in vitro characterization of the gene product and mutant analysis.in this work the neurospora crassa al-3 gene function was determined. geranylgeranyl pyrophosphate (ggpp) synthase activity was measured in al-2 fgsc 313 and al-3 rp100 fgsc 2082 mutant strains by in vitro synthesis methods. this experiment showed that al-3 rp100 mutant expresses a reduced ggpp synthase activity. the mutated al-3 gene was cloned and sequenced; a single missense mutation was found changing serine into asparagine. genetic complementation was performed by escherichia coli transform ...19938350190
chromosome rearrangements recovered following transformation of neurospora crassa.new 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
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
heterologous expression of mating-type genes in filamentous fungi.podospora anserina and neurospora crassa, two filamentous heterothallic ascomycetes, have a single mating-type locus with two alternate forms called mat+ and mat- and a and a, respectively. mating type controls entry into the sexual cycle, events subsequent to fertilization, and, in n. crassa, prevents the formation of mixed mating-type heterokaryons. the mating types of these two organisms display similarity in their dna structure and in the encoded polypeptides involved in fertilization. here ...19938341677
calcium and microorganisms.this review followed from experiments suggesting that some fungi do not require calcium. it was found that many studies of a calcium requirement in microorganisms had assumed specificity for chelation agents such as egta and a23187, which the reagents did not possess. early studies still cited today often preceded the recognition that microorganisms required manganese and zinc. as a result of both of these misunderstandings, there was rarely any attempt to replace calcium by other important trac ...19938338620
identification of a g protein alpha subunit from neurospora crassa that is a member of the gi family.heterotrimeric g proteins, consisting of alpha, beta, and gamma subunits, are implicated in major signal transduction pathways controlling a diversity of functions in eukaryotic organisms. in the filamentous fungus neurospora crassa, g proteins are implicated in the regulation of several environmental responses. as a first step in studying the role of g proteins in these processes, we have cloned the genes for two alpha subunits, gna-1 and gna-2, from neurospora. the genes are located on differe ...19938325859
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 crassa.in 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
choline: its role in the growth of filamentous fungi and the regulation of mycelial morphology.choline is an essential metabolite for the growth of filamentous fungi. it occurs most notably as a component of the major membrane phospholipid, phosphatidyl choline (lecithin), and fulfills a major role in sulphate metabolism in the form of choline-o-sulphate in many species. choline is usually synthesised endogenously, but exogenous choline can also be taken up, either to compensate for metabolic deficiencies in choline-requiring mutants such as those of aspergillus nidulans and neurospora cr ...19938318261
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
the positive-acting sulfur regulatory protein cys3 of neurospora crassa: nuclear localization, autogenous control, and regions required for transcriptional activation.the positive-acting global sulfur regulatory protein, cys3, of neurospora crassa turns on the expression of a family of unlinked structural genes that encode enzymes of sulfur catabolism. cys3 contains a leucine zipper and an adjacent basic region (b-zip), which together constitute a bipartite sequence-specific dna-binding domain. specific anti-cys3 antibodies detected a protein of the expected size in nuclear extracts of wild-type neurospora under conditions in which the sulfur circuit is activ ...19938316209
two binding sites of inhibitors in nadh: ubiquinone oxidoreductase (complex i). relationship of one site with the ubiquinone-binding site of bacterial glucose:ubiquinone oxidoreductase.the effect of ten naturally occurring and two synthetic inhibitors of nadh:ubiquinone oxidoreductase (complex i) of bovine heart, neurospora crassa and escherichia coli and glucose:ubiquinone oxidoreductase (glucose dehydrogenase) of gluconobacter oxidans was investigated. these inhibitors could be divided into two classes with regard to their specificity and mode of action. class i inhibitors, including the naturally occurring piericidin a, annonin vi, phenalamid a2, aurachins a and b, thiangaz ...19948307034
the primary structure of sheep liver cytosolic serine hydroxymethyltransferase and an analysis of the evolutionary relationships among serine hydroxymethyltransferases.the complete amino-acid sequence of sheep liver cytosolic serine hydroxymethyltransferase was determined from an analysis of tryptic, chymotryptic, cnbr and hydroxylamine peptides. each subunit of sheep liver serine hydroxymethyltransferase consisted of 483 amino-acid residues. a comparison of this sequence with 8 other serine hydroxymethyltransferases revealed that a possible gene duplication event could have occurred after the divergence of animals and fungi. this analysis also showed independ ...19948305478
purification of neurospora crassa cytosolic serine hydroxymethyltransferase. 19938304214
pclk1 and pclt5--two linear mitochondrial plasmids from unrelated claviceps purpurea strains: a comparison.pclt5, a linear mitochondrial (mt) plasmid from claviceps purpurea, strain t5, was sequenced and compared to pclk1, a linear mt plasmid from an unrelated c. purpurea strain. both plasmids have terminal proteins (tps) at their inverted terminal repeats (tlr). the tlrs of both plasmids show short conserved sequences, which are probably involved in plasmid transcription and replication. the coding capacity of pclt5 and pclk1 is similar: there are two large orfs (orf1 and orf2) homologous to the dna ...19938302935
the alkane-inducible candida maltosa ali1 gene product is an nadh:ubiquinone oxidoreductase subunit homologue.the ali1 gene product in candida maltosa was previously shown to be essential for n-alkane assimilation, possibly as a transcription factor [hwang et al., gene 106 (1991) 61-69]. we show that the predicted sequence is highly homologous to a subunit of respiratory complex i from another fungus, neurospora crassa, and from bos taurus. the predicted protein contains a motif conserved in this subunit from mitochondria, chloroplasts and bacteria. it also contains an n-terminal sequence that suggests ...19938299970
promoter analysis of the bli-7/eas gene.expression of the neurospora crassa gene bli-7, (identical with eas, and ccg-2), is induced by blue light, as well as glucose- or nitrogen-starvation. a promoter analysis was performed by an assay that does not involve promoter-reporter constructs but rather the insertion of foreign dna into the transcribed sequence. to detect regulatory elements a series of deletions in the upstream region was generated. the inducibility of the gene, in response to the three inducing conditions mentioned, is lo ...19938299154
purification of the nadh:ubiquinone oxidoreductase (complex i) of the respiratory chain from the inner mitochondrial membrane of solanum tuberosum.the plant nadh:ubiquinone oxidoreductase (or complex i) was isolated from potato (solanum tuberosum) mitochondria. the multisubunit enzyme was solubilized with detergents, triton x-100 and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (chaps), out of the inner mitochondrial membranes and purified by hydroxylapatite and gel filtration chromatography. the preparation was found to be virtually free of any atpase or transhydrogenase contamination. complex i of potato is composed of at le ...19948294484
genesis of eukaryotic transcriptional activator and repressor proteins by splitting a multidomain anabolic enzyme.the genes necessary for the correctly regulated catabolism of quinate in aspergillus nidulans and neurospora crassa are controlled at the level of transcription by a dna-binding activator protein and a repressor protein that directly interact with one another. the repressor protein is homologous throughout its length with the three c-terminal domains of a pentafunctional enzyme catalysing five consecutive steps in the related anabolic shikimate pathway. we now report that the activator protein i ...19938294040
the leu-1 gene of neurospora crassa: nucleotide and deduced amino acid sequence comparisons.the neurospora crassa leu-1 gene encodes beta-isopropylmalate dehydrogenase (ipmdh; ec 1.1.1.85), an enzyme in the leucine biosynthetic pathway. we determined the nucleotide sequence of the entire leu-1 gene and of four independent cdna clones. by comparing the genomic and cdna sequences, four introns were identified in the 5' portion of the gene and a single open reading frame was established. one of the introns is located within the 5'-noncoding region of the transcript. the deduced amino acid ...19938294021
expression of mitochondrial genes in the germinating conidia of neurospora crassa.the germinating asexual spores (conidia) of neurospora crassa were employed to study steps in the accumulation of transcripts of groups of mitochondrial genes, including those for peptide subunits of cytochrome c oxidase (co), atpase (atp), and apocytochrome b (cob). physically clustered groups of genes were expressed as cohorts: transcripts of the atp8-atp6-mtatp9-co2 genes were almost undetectable in the dormant spores, and they accumulated rapidly as a group immediately after spore activation ...19948289326
dna recognition by the nit2 nitrogen regulatory protein: importance of the number, spacing, and orientation of gata core elements and their flanking sequences upon nit2 binding.nit2, a global positive-acting regulatory protein in neurospora crassa, activates the expression of a series of unlinked structural genes in the nitrogen regulation circuit. nit2 binding sites in the promoter region of the nit-3, alc, and lao genes are very different in sequence context except for the presence of at least two copies of a gata core sequence. changing a single nucleotide of only one of two closely spaced gata core elements abolished nit2 binding, demonstrating their importance for ...19948286388
organelle movements in the wild type and wall-less fz;sg;os-1 mutants of neurospora crassa are mediated by cytoplasmic microtubules.the cellular basis of organelle transport in filamentous fungi is still unresolved. here we have studied the intracellular movement of mitochondria and other organelles in the fungus neurospora crassa. four different model systems were employed: hyphae, protoplasts, a cell wallless mutant, and experimentally generated small, flattened cell fragments of the mutant cells. organelle movements were visualized by dic optics and computer-enhanced video microscopy. in all cell models the transport of o ...19938282762
the interplay of light and the circadian clock. independent dual regulation of clock-controlled gene ccg-2(eas).ambient light is the major agent mediating entrainment of circadian rhythms and is also a major factor influencing development and morphogenesis. we show that in neurospora crassa the expression of clock-controlled gene 2 (ccg-2), a gene under the control of the circadian clock and allelic to the developmental gene easy wettable (eas), is regulated by light in wild-type strains. light elicits a direct and important physiological effect on ccg-2(eas) expression as demonstrated using several mutan ...19938278550
cloning and characterisation of the cytochrome c gene of aspergillus nidulans.the cytochrome c gene (cyca) of the filamentous fungus aspergillus nidulans has been isolated and sequenced. the gene is present in a single copy per haploid genome and encodes a polypeptide of 112 amino acid residues. the nucleotide sequence of the a. nidulans cyca gene shows 87% identity to the dna sequence of the neurospora crassa cytochrome c gene, and approximately 72% identity to the sequence of the saccharomyces cerevisiae iso-1-cytochrome c gene (cyc1). the s. cerevisiae cyc1 gene was us ...19948277943
an escherichia coli gene showing a potential ancestral relationship to the genes for the mitochondrial import site proteins isp42 and mom38.an orf (orft) of 1911 base pairs, upstream of the hip operon in escherichia coli at map position 33.82 has been identified. the protein encoded by this sequence is predicted to have a molecular mass of 68,249 da and the carboxyterminal 276 residues shows 26.8% and 25.4% identity with the import site proteins isp42 and mom38 from the mitochondrial outer membrane of saccharomyces cerevisiae and neurospora crassa, respectively. these mitochondrial membrane proteins have been shown to be essential c ...19938274505
pas10 is a tetratricopeptide-repeat protein that is essential for the import of most matrix proteins into peroxisomes of saccharomyces cerevisiae.pas mutants of saccharomyces cerevisiae are disturbed in peroxisome assembly (pas) and proliferation. here we report the characterization of the pas10 gene and its product (pas10) that is essential for the import of a large subset of proteins into the peroxisomal matrix. pas10, a protein of 69 kda, is a member of the tetratricopeptide repeat, or snap helix, protein family, characterized by several direct repeats of a degenerate 34-amino acid motif (sikorski, r. s., boguski, m. s., goebl, m. & hi ...19938265627
effect of site-directed mutagenesis of conserved aspartate and arginine residues upon farnesyl diphosphate synthase activity.all polyprenyl synthases catalyze the condensation of the allylic substrate, isopentenyl diphosphate, with a specific homoallylic diphosphate substrate. polyprenyl synthases from homo sapiens, ratus rattus, escherichia coli, saccharomyces cerevisiae, neurospora crassa, and erwinia herbicola contain two conserved "aspartate-rich domains" (ashby, m.n., and edwards, p.a. (1992) j. biol. chem. 267, 4128-4136). in order to determine the importance of these domains in catalysis, the conserved aspartat ...19938262934
higher-plant cofactor-independent phosphoglyceromutase: purification, molecular characterization and expression.cofactor-independent phosphoglyceromutase (pgm) was purified to homogeneity from developing castor seed endosperm. immunological characterization using monospecific antisera raised against this protein indicates that the enzyme is located in the cytosol and that there is no immunologically related polypeptide in the leucoplast from this tissue. isolation and sequence determination of full-length cdna clones for castor and tobacco pgm demonstrate that the protein is highly conserved in these plan ...19938260624
characterization of the 3-dehydroquinase domain of the pentafunctional arom protein, and the quinate dehydrogenase from aspergillus nidulans, and the overproduction of the type ii 3-dehydroquinase from neurospora crassa.the arom protein of aspergillus nidulans is a multidomain pentafunctional polypeptide that is active as a dimer and catalyses steps 2-6 in the prechorismate section of the shikimate pathway. the three c-terminal domains (including the type i 3-dehydroquinase) of the arom protein are homologous with the qutr-encoded qutr protein that represses transcription of the eight genes comprising the quinic acid utilization (qut) gene cluster, and the two n-terminal domains are homologous with the quta-enc ...19938257437
the sugar beet mitochondrial genome contains an orf sharing sequence homology with the gene for the 30 kda subunit of bovine mitochondrial complex i.from a sugar beet mitochondrial dna library, we have isolated an open reading frame (orf192) showing extensive homology to the gene for the 30 kda subunit of the bovine mitochondrial complex i (nadh: ubiquinone reductase). the orf192 was found to be actively transcribed to give an rna of approximately 1.0 kb. we have designated this gene nad9. transcripts from the nad9 locus are edited by five c to u transitions, increasing similarity with the amino acid sequence of the corresponding bovine and ...19938246903
de novo methylation of repeated sequences in coprinus cinereus.we have examined the stability of duplicated dna sequences in the sexual phase of the life cycle of the basidiomycete fungus, coprinus cinereus. we observed premeiotic de novo methylation in haploid nuclei containing either a triplication, a tandem duplication, or an ectopic duplication. methylation changes were not observed in unique sequences. repeated sequences underwent methylation changes during the dikaryotic stage. in one cross, 27% of the segregants exhibited methylation-directed gene in ...19938244000
amplification of the nucleolus organizer region during the sexual phase of neurospora crassa.previously we have shown that the nucleolus organizer region (nor) of neurospora crassa displays frequent size changes during crosses. in these initial studies, we observed that decreases in nor size are far more common than increases. here, we have investigated the inheritance of nor size in a strain with an unusually small nor. we call this strain sno for small nucleolus organizer. we found that progeny that inherit their rdna from sno receive either an nor that is larger than that of sno or, ...19938243164
identification of the heat shock protein of neurospora crassa corresponding to the stress-inducible peroxidase.heat shock and other stress treatments, resulting in thermotolerance in neurospora crassa cells, stimulate the induction of a peroxidase at a high level. the putative gene encoding this heat shock-induced peroxidase (hspp) has been cloned, using a cdna clone of the manganese peroxidase of phanerochaete chrysosporium, as a probe. northern blot analysis of total rna from heat-shocked cell showed the stress-dependent accumulation of a approximately 10 kb transcript. the identity of the hsp, corresp ...19938240345
hypersensitive sites in the 5' promoter region of nit-3, a highly regulated structural gene of neurospora crassa.the nit-3 gene of the filamentous fungus neurospora crassa encodes nitrate reductase, the enzyme which catalyzes the first step in nitrate assimilation. the nit-3 gene is subject to a high degree of regulation by metabolic inducers and repressors, and its expression requires two distinct trans-acting regulatory proteins. hypersensitive sites in the 5' dna sequence upstream of the nit-3 gene were mapped with the use of three different nucleases as molecular probes. six hypersensitive sites, three ...19938226616
structural characterization and expression analysis of the neurospora conidiation gene con-6.the gene con-6 of neurospora crassa is expressed during the formation of asexual spores (conidia), but it is not expressed in mycelium. con-6 mrna appears upon induction of conidiation and reaches high levels at the late stages of conidiation, and in mature conidia. the con6 polypeptide and a con6-beta-gal fusion protein were present at high levels only in free conidia. shortly after spore germination con-6 mrna disappears and the con6 polypeptide is degraded. con6 is a small, hydrophilic polype ...19938224542
higher plant mitochondria encode an homologue of the nuclear-encoded 30-kda subunit of bovine mitochondrial complex i.we describe the structure and expression of a wheat mitochondrial gene, which codes for a subunit of mitochondrial nadh dehydrogenase. the deduced protein sequence has 70% similarity to the 30-kda subunit of bovine mitochondrial complex i and 65% similarity to the 31-kda subunit of neurospora crassa complex i, components of the iron-sulfur-protein fraction, both nuclear-encoded proteins. we named this wheat mitochondrial gene as nad9. the wheat nad9 gene is transcribed in a single mrna of 0.9 kb ...19938223639
functional cooperation of mitochondrial protein import receptors in yeast.we have identified a 20 kda yeast mitochondrial outer membrane protein (termed mas20) which appears to function as a protein import receptor. we cloned, sequenced and physically mapped the mas20 gene and found that the protein is homologous to the mom19 import receptor from neurospora crassa. mas20 and mom19 contain the sequence motif f-x-k-a-l-x-v/l, which is repeated several times with minor variations in the mas70/mom72 receptors. to determine how mas20 functions together with the previously ...19938223428
amino-acid substitutions in the zinc finger of nit2, the nitrogen regulatory protein of neurospora crassa, alter promoter element recognition.nit2, the major nitrogen regulatory protein of neurospora crassa mediates nitrogen catabolite derepression of the structural genes which specify enzymes of nitrogen catabolism. the promoter of the structural gene for l-amino acid oxidase, a nitrogen-regulated enzyme, was found to contain two nit2 binding sites, each with two copies of a gata core consensus sequence. site-directed mutagenesis was employed to create amino-acid substitutions within the single zinc-finger region of nit2, which serve ...19938221929
cloning and sequence analysis of the glucoamylase gene of neurospora crassa.a 1.0-kb dna fragment, corresponding to an internal region of the neurospora crassa glucoamylase gene, gla-1, was generated from genomic dna by the polymerase chain reaction, using oligonucleotide primers which had been deduced from the known n-terminal amino-acid sequence or from consensus regions within the aligned amino-acid sequences of other fungal glucoamylases. the fragment was used to screen an n. crassa genomic dna library. one clone contained the gene together with flanking regions and ...19938221928
effects of osmotic stress and growth stage on cellular ph and polyphosphate metabolism in neurospora crassa as studied by 31p nuclear magnetic resonance spectroscopy.high-resolution 31p-nmr was employed to investigate the effects of growth stage and environmental osmolarity on changes of polyphosphate metabolism and intracellular ph in intact neurospora crassa cells. our study showed that changes of these parameters were growth-dependent. the ratio of polyphosphate to orthophosphate in vacuoles increased from 2.4 to 13.5 in n. crassa as cells grew from early log phase to stationary phase. cytoplasmic ph and vacuolar ph changed, respectively, from 6.91 and 6. ...19938218356
transcriptional activation of a cycloheximide-inducible gene encoding laccase is mediated by cpc-1, the cross-pathway control gene, in neurospora crassa.expression of the laccase gene (lacc) of neurospora crassa is transcriptionally inducible by the protein synthesis inhibitor cycloheximide. a lni-1 mutation, conferring the laccase non-inducible phenotype, was found to be a cpc-1 allele. northern blots probed with plasmid pla1, which carries the lacc gene revealed that the cpc-1 mutation abolishes the induced transcription of the lacc gene, indicating requirement of the cpc-1 gene for transcriptional activation of the lacc gene. in northern blot ...19948208246
preproteins of chloroplast envelope inner membrane contain targeting information for receptor-dependent import into fungal mitochondria.the amino-terminal transit sequences of two preproteins destined for the chloroplast inner envelope membrane show similarities to mitochondrial presequences in the prevalence of positive charges and the potential formation of an amphipathic alpha-helix. we studied if these preproteins could be imported into mitochondria and found a low, yet significant import into isolated plant mitochondria. the plant mitochondria were previously shown not to import precursors of chloroplast stromal or thylakoi ...19948206957
new mutations that suppress mating-type vegetative incompatibility in neurospora crassa.the mating-type locus in the ascomycete neurospora crassa functions as a vegetative-incompatibility locus during asexual growth such that a+a heterokaryons and a/a partial diploids are inhibited in their growth. in this study, we sought mutations that suppress mating-type associated vegetative incompatibility by using a/a partial diploids. mutants were selected as spontaneous escapes from inhibited growth. suppressors were identified by selecting escapes that retained the capacity to mate with b ...19948200515
light signals are transduced to the phosphorylation of 15 kda proteins in neurospora crassa.a microsomal fraction prepared from the mycelia of the band (bd) strain of neurospora crassa showed enhanced phosphorylation of two small proteins with molecular masses of around 15 kda (ps15) by the irradiation of the reaction mixture containing [gamma-32p]atp at 0 degrees c for 1 s with blue light (450 nm, 6 mumol/m2/s or 420 nm, 80 mumol/m2/s). the reaction was stopped at 5 s of incubation at 0 degrees c after blue light irradiation. the light effect could not be detected in ps15, when a micr ...19948200450
a simple and efficient system for targeting dna to the am locus of neurospora crassa.we have developed a system of recipient strains and donor plasmids that allows targeting of dna sequences to the am locus of neurospora crassa. a recipient strain was constructed that contains the 3' two-thirds of the bacterial hygromycin b (hy) phosphotransferase-encoding gene (hph) in single copy downstream from the am structural gene encoding nadp-specific glutamate dehydrogenase. plasmids have been constructed that contain am, but with the 5' end of hph downstream from am. resistance to hy c ...19948194755
intergeneric complementation of a circadian rhythmicity defect: phylogenetic conservation of structure and function of the clock gene frequency.the neurospora crassa frequency locus encodes a 989 amino acid protein that is a central component, a state variable, of the circadian biological clock. we have determined the sequence of all or part of this protein and surrounding regulatory regions from additional fungi representing three genera and report that there is distinct, preferential conservation of the frequency open reading frame (orf) as compared with non-coding sequences. within the coding region, many of the domain hallmarks of t ...19948194516
nitrogen limitation induces expression of the avirulence gene avr9 in the tomato pathogen cladosporium fulvum.the avirulence gene avr9 of the fungal tomato pathogen cladosporium fulvum encodes a race-specific peptide elicitor that induces the hypersensitive response in tomato plants carrying the complementary resistance gene cf9. the avr9 gene is not expressed under optimal growth conditions in vitro, but is highly expressed when the fungus grows inside the tomato leaf. in this paper we present evidence for the induction of avr9 gene expression in c. fulvum grown in vitro under conditions of nitrogen li ...19948190081
the proteolipid subunit of the neurospora crassa vacuolar atpase: isolation of the protein and the vma-3 gene.we have isolated the proteolipid subunit from the vacuolar atpase of neurospora crassa, using ion-exchange chromatography. we have also isolated several cdna clones and the corresponding genomic dna that encodes this subunit. the derived protein sequence indicates that the polypeptide is composed of 161 amino acid residues with an m(r) of 16,328 kda. the gene encoding the proteolipid, named vma-3, is unusual in several respects. it contains four introns and, unlike other fungal genes, has non-co ...19948190074
genetic risk assessment and specific-locus mutations in the ad-3 region of neurospora crassa.data from experiments on the induction of specific-locus mutations in model systems are used in genetic risk assessment to estimate potential adverse effects in the human population. in such assessments with radiation or chemical mutagens, the following information is required: a) spontaneous and induced forward-mutation frequencies, b) dose-response curves for the overall induction of specific-locus mutations, c) genetic characterization of spontaneous and induced mutations, and d) dose-respons ...19948187730
on the structure of mitochondrial porins and its homologies with bacterial porins.by use of computer modelling, we have predicted a model of 16 transmembrane beta-strands for mitochondrial porins structure from human, saccharomyces cerevisiae, neurospora crassa and dictyostelium discoideum. the proposed model takes into account biochemical and immunological data reported in the literature, as well as electrophysiological results obtained with yeast mitochondrial porins with mutations at selected amino acids. the predicted structure is very similar to that of some bacterial po ...19948179626
characterization of a 3-dehydroquinase gene from actinobacillus pleuropneumoniae with homology to the eukaryotic genes qa-2 and qute.a gene was cloned from actinobacillus pleuropneumoniae strain 4074 by complementation of an arod strain of escherichia coli. the e. coli gene arod codes for a 3-dehydroquinase enzyme of type i, active in the aromatic biosynthesis pathway. the a. pleuropneumoniae gene, termed aroq, displays no base or amino acid sequence homology to arod of e. coli. it is instead homologous to the qute and qa-2 genes, respectively of aspergillus nidulans and neurospora crassa. these genes code for 3-dehydroquinas ...19948170389
efficient but aberrant cleavage of mitochondrial precursor proteins by the chloroplast stromal processing peptidase.cytosol-synthesized chloroplast and mitochondrial precursor proteins are proteolytically processed after import by highly specific, metal-dependent soluble enzymes: the stromal processing peptidase (spp) and the matrix processing peptidase (mpp), respectively. we have used in vitro processing assays to compare the reaction specificities of highly purified preparations of pea spp and neurospora crassa mpp, both of which are unable to cleave a variety of 'foreign' proteins. we show that spp can cl ...19948168539
in organello assembly of respiratory-chain complex i: primary structure of the 14.8 kda subunit of neurospora crassa complex i.a cdna encoding the 14.8 kda subunit of complex i from neurospora crassa was cloned and sequenced. the deduced primary structure of this subunit reveals a predominantly hydrophilic protein containing no obvious membrane-spanning domain. in agreement with this characteristic, we have localized the 14.8 kda subunit in the peripheral arm of the enzyme. the 14.8 kda subunit was found to be conserved in mammalian complex i. the conservation of this subunit in such distantly related organisms suggests ...19948166654
characterization of al-2, the phytoene synthase gene of neurospora crassa. cloning, sequence analysis, and photoregulation.we have cloned the al-2 gene of neurospora crassa and have analyzed its structure and regulation. the gene encodes a 603-residue polypeptide with a segment homologous to prokaryotic and other eukaryotic phytoene synthases. rna measurements showed that the level of al-2 mrna increased over 30-fold in photoinduced mycelia compared with dark-grown mycelia. this observation is consistent with the fact that carotenoid biosynthesis is induced by blue light during growth of n. crassa mycelia. the photo ...19948163509
specific recognition of mitochondrial preproteins by the cytosolic domain of the import receptor mom72.the import receptor mom72 constitutes part of the protein translocation machinery of the outer mitochondrial membrane, the receptor-general insertion pore complex. the protein contains a membrane anchor at the nh2 terminus and a large cytosolic domain. in yeast and neurospora crassa the cytosolic domain comprises about 570-580 amino acid residues. the cytosolic domain of yeast mom72 was purified after expression in escherichia coli as a homogeneous monomeric protein. it can recognize precursor p ...19948163488
formation of morphological differentiation patterns in the ascomycete neurospora crassa.morphological differentiation patterns--among them concentric rings and radial zonations--can be induced in the band-mutant of neurospora crassa by appropriate experimental conditions, in particular by a mere shift of certain salt concentrations in the medium. the role of initial experimental conditions is examined and, furthermore, the influences of artificially induced phase differences are analyzed with respect to pattern formation. while the concentric ring pattern is due to some (endogenous ...19938155572
a series of yeast/escherichia coli lambda expression vectors designed for directional cloning of cdnas and cre/lox-mediated plasmid excision.a series of saccharomyces cerevisiae/escherichia coli lambda/plasmid expression vectors have been constructed which allow easy excision of the plasmid sequences from lambda. features of six are described, and two designated lambda pg15 and lambda ad5, are characterized in detail. transcription of cloned sequences is controlled by the alternative promoters, adh2, pgk, gal10 and sv40 early, and by the cyc1 transcriptional terminator. unique ecori and xhoi restriction sites in the intervening polyl ...19938154182
homologs of the yeast neck filament associated genes: isolation and sequence analysis of candida albicans cdc3 and cdc10.morphogenesis in the yeast saccharomyces cerevisiae consists primarily of bud formation. certain cell division cycle (cdc) genes, cdc3, cdc10, cdc11, cdc12, are known to be involved in events critical to the pattern of bud growth and the completion of cytokinesis. their products are associated with the formation of a ring of neck filaments that forms at the region of the mother cell-bud junction during mitosis. morphogenesis in candida albicans, a major fungal pathogen of humans, consists of bot ...19948152419
gene inactivation triggered by recognition between dna repeats.this chapter focuses on phenomena of gene inactivation resulting from the presence of repeated gene copies within the genome of plants and fungi, and on their possible relationships to homologous dna-dna interactions. emphasis is given to two related premeiotic processes: methylation induced premeiotically (mip) and repeat-induced point mutation (rip) which take place in the fungi ascobolus immersus and neurospora crassa, respectively. the relationships between these processes and genetic recomb ...19948143804
the search for the right partner: homologous pairing and dna strand exchange proteins in eukaryotes.finding the right partner is a central problem in homologous recombination. common to all models for general recombination is a homologous pairing and dna strand exchange step. in prokaryotes this process has mainly been studied with the reca protein of escherichia coli. two approaches have been used to find homologous pairing and dna strand exchange proteins in eukaryotes. a biochemical approach has resulted in numerous proteins from various organisms. almost all of these proteins are biochemic ...19948143796
similarities between a soybean nodulin, neurospora crassa sulphate permease ii and a putative human tumour suppressor. 19948140616
inactivation of the neurospora crassa gene encoding the mitochondrial protein import receptor mom19 by the technique of "sheltered rip".we have used a technique referred to as "sheltered rip" (repeat induced point mutation) to create mutants of the mom-19 gene of neurospora crassa, which encodes an import receptor for nuclear encoded mitochondrial precursor proteins. sheltered rip permits the isolation of a mutant gene in one nucleus, even if that gene is essential for the survival of the organism, by sheltering the nucleus carrying the mutant gene in a heterokaryon with an unaffected nucleus. furthermore, the nucleus harboring ...19948138148
3-carboxy-cis,cis-muconate lactonizing enzyme from neurospora crassa: an alternate cycloisomerase motif.3-carboxy-cis,cis-muconate lactonizing enzyme (cmle; ec 5.5.1.5) from neurospora crassa catalyzes the reversible gamma-lactonization of 3-carboxy-cis,cis-muconate by a syn-1,2 addition-elimination reaction. the stereochemical and regiochemical course of the reaction is (i) opposite that of cmle from pseudomonas putida (ec 5.5.1.2) and (ii) identical to that of cis,cis-muconate lactonizing enzyme (mle; ec 5.5.1.1) from p. putida. in order to determine the mechanistic and evolutionary relationship ...19948132467
molybdenum(vi) salts convert the xanthine oxidoreductase apoprotein into the active enzyme in mouse l929 fibroblastic cells.the mouse l929 fibroblastic cell line presents low, but detectable, levels of the mrna encoding xanthine oxidoreductase under basal conditions, and it responds to type i and type ii interferons by inducing the expression of the transcript [falciani, ghezzi, terao, cazzaniga, and garattini (1992) biochem. j. 285, 1001-1008]. this cell line, however, does not show any detectable amount of xanthine oxidoreductase enzymic activity, either before or after treatment with the cytokines. molybdenum(vi) ...19948129733
negative feedback defining a circadian clock: autoregulation of the clock gene frequency.the frequency (frq) locus of neurospora crassa was originally identified in searches for loci encoding components of the circadian clock. the frq gene is now shown to encode a central component in a molecular feedback loop in which the product of frq negatively regulated its own transcript, which resulted in a daily oscillation in the amount of frq transcript. rhythmic messenger rna expression was essential for overt rhythmicity in the organism and no amount of constitutive expression rescued no ...19948128244
at least three genes are responsible for benomyl-resistance in metarhizium anisopliae.four benomyl-resistant mutants isolated from metarhizium anisopliae were 10 to 500 times more resistant than the original mt strain. the resistance markers analysed in three of these mutants were due to three different mutations and no additive effect of these genes was observed in double mutants. the four mutants presented normal conidiation in the presence or absence of benomyl and no sensitivity or resistance to temperature. probably m. anisopliae has a mechanism of benomyl resistance differi ...19948127229
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