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learning to "think like a geneticist" with the de serres ad-3 forward-mutation test in neurospora crassa. 199910610427
a highly conserved mechanism of regulated ribosome stalling mediated by fungal arginine attenuator peptides that appears independent of the charging status of arginyl-trnas.the arg attenuator peptide (aap) is an evolutionarily conserved peptide involved in arg-specific negative translational control. it is encoded as an upstream open reading frame (uorf) in fungal mrnas specifying the small subunit of arg-specific carbamoyl phosphate synthetase. we examined the functions of the saccharomyces cerevisiae cpa1 and neurospora crassa arg-2 aaps using translation extracts from s. cerevisiae, n. crassa, and wheat germ. synthetic rna containing aap and firefly luciferase ( ...199910608810
posttranscriptional gene silencing in neurospora by a recq dna helicase.the phenomenon of posttranscriptional gene silencing (ptgs), which occurs when a transgene is introduced into a cell, is poorly understood. here, the qde-3 gene, which is required for the activation and maintenance of gene silencing in the fungus neurospora crassa, was isolated. sequence analysis revealed that the qde-3 gene belongs to the recq dna helicase family. the qde3 protein may function in the dna-dna interaction between introduced transgenes or with an endogenous gene required for gene- ...199910600745
analysis of the membrane domain of the gastric h(+)/k(+)-atpase.a structure of the catalytic or alpha subunit of the h(+)/k(+)-atpase, with ten transmembrane segments, and of the beta subunit, with a single such segment, was established using a combination of tryptic cleavage and peptide sequencing and in vitro translation. sites at which covalent ligands bind to external surfaces were also defined by cleavage, separation and sequencing. cys813 was found to be the common covalent binding site for all the substituted pyridyl methylsulfinyl benzimidazoles. the ...200010600685
biogenesis and function of the yeast plasma-membrane h(+)-atpase.one of the most abundant proteins in the yeast plasma membrane is the p-type h(+)-atpase that pumps protons out of the cell, supplying the driving force for a wide array of h(+)-dependent cotransporters. the atpase is a 100 kda polypeptide, anchored in the lipid bilayer by 10 transmembrane alpha-helices. it is structurally and functionally related to the p-type na(+),k(+)-, h(+),k(+)- and ca(2+)-atpases of animal cells and the h(+)-atpases of plant cells, and it shares with them a characteristic ...200010600684
crystallization, structure and dynamics of the proton-translocating p-type atpase.large single three-dimensional crystals of the dodecylmaltoside complex of the neurospora crassa plasma membrane h(+)-atpase (h(+) p-atpase) can be grown in polyethylene-glycol-containing solutions optimized for moderate supersaturation of both the protein surfaces and detergent micellar region. large two-dimensional h(+) p-atpase crystals also grow on the surface of such mixtures and on carbon films located at such surfaces. electron crystallographic analysis of the two-dimensional crystals gro ...200010600683
cellular role of the v-atpase in neurospora crassa: analysis of mutants resistant to concanamycin or lacking the catalytic subunit a.vacuolar atpases (v-atpases) are large complex enzymes that are structural and mechanistic relatives of f(1)f(o)-atpases. they hydrolyze atp and pump protons across membranes to hyperpolarize membranes and, often, to acidify cellular compartments. the proton gradients generated are used to drive the movement of various compounds across membranes. v-atpases are found in membranes of archaebacteria and some eubacteria, in various components of the endomembrane system of all eukaryotes and in the p ...200010600678
disruption of the gene for hsp30, an alpha-crystallin-related heat shock protein of neurospora crassa, causes defects in import of proteins into mitochondria.the gene for hsp30, the only known alpha-crystallin-related heat shock protein of neurospora crassa, was disrupted by repeat-induced point mutagenesis, leading to loss of cell survival at high temperature. hsp30, which is not synthesized at 30 degrees c, associates reversibly with the mitochondria at high temperature (45 degrees c). in this study, we found that import of selected proteins into internal compartments of mitochondria, following their synthesis in the cytosol, was severely impaired ...199910595587
similarity pattern analysis in mutational distributions.the validity and applicability of the statistical procedure - similarity pattern analysis (span) - to the study of mutational distributions (mds) was demonstrated with two sets of data. the first was mutational spectra (ms) for 697 gc to at transitions produced with eight alkylating agents (aas) in the laci gene of escherichia coli. the second was a recently summarized data on the distributions of 11562 spontaneous, radiation- and chemical-induced forward mutations in the ad-3 region of heteroka ...199910592318
mitop, the mitochondrial proteome database: 2000 update.mitop (http://www.mips.biochem.mpg.de/proj/medgen/mitop/) is a comprehensive database for genetic and functional information on both nuclear- and mitochondrial-encoded proteins and their genes. the five species files--saccharomyces cerevisiae, mus musculus, caenorhabditis elegans, neurospora crassa and homo sapiens--include annotated data derived from a variety of online resources and the literature. a wide spectrum of search facilities is given in the overlapping sections 'gene catalogues', 'pr ...200010592209
mips: a database for genomes and protein sequences.the munich information center for protein sequences (mips-gsf), martinsried, near munich, germany, continues its longstanding tradition to develop and maintain high quality curated genome databases. in addition, efforts have been intensified to cover the wealth of complete genome sequences in a systematic, comprehensive form. bioinformatics, supporting national as well as european sequencing and functional analysis projects, has resulted in several up-to-date genome-oriented databases. this repo ...200010592176
transfer of neurospora kalilo plasmids among species and strains by introgression.there are four different variants of the kalilo "family" of linear mitochondrial plasmids. this family is found in several heterothallic species and one pseudohomothallic species of neurospora, as well as in one homothallic species of gelasinospora. the mode of dispersal of these plasmids is not known. horizontal transmission has proved difficult to demonstrate. another possibility is transfer by introgression, and this is modelled in the present paper. we have used introgression and subsequent ...199910591968
recombinational landscape across a 650-kb contig on the right arm of linkage group v in neurospora crassa.we have established a 650-kb walk spanning the sp to ure-1 interval on neurospora crassa linkage group v. loci covered by the walk are, from proximal to distal, sp; rec-2; ure-2; dna polymerase delta; am; gul-1; ace-5; and ure-1. we have found extensive dna polymorphism in this region and used this to examine the recombinational landscape. crossovers are not evenly distributed over the region covered by the contig.199910591967
permeabilization of fungal membranes by plant defensins inhibits fungal growth.we used an assay based on the uptake of sytox green, an organic compound that fluoresces upon interaction with nucleic acids and penetrates cells with compromised plasma membranes, to investigate membrane permeabilization in fungi. membrane permeabilization induced by plant defensins in neurospora crassa was biphasic, depending on the plant defensin dose. at high defensin levels (10 to 40 microm), strong permeabilization was detected that could be strongly suppressed by cations in the medium. th ...199910584003
isolation and characterization of neurospora crassa nucleoside diphosphate kinase ndk-1.we have previously reported that phosphorylation of a 15-kda protein increased after blue-light irradiation in neurospora crassa. in this study, the 15-kda protein was purified using four columns; deae-cellulose, blue-sepharose, sp-sepharose and mono q. the 15-kda protein was shown to be homologous with nucleoside diphosphate kinase by amino acid sequencing and was also shown to possess nucleoside diphosphate kinase activity. a gene encoding n. crassa nucleoside diphosphate kinase, ndk-1, was is ...199910583364
the tom core complex: the general protein import pore of the outer membrane of mitochondria.translocation of nuclear-encoded preproteins across the outer membrane of mitochondria is mediated by the multicomponent transmembrane tom complex. we have isolated the tom core complex of neurospora crassa by removing the receptors tom70 and tom20 from the isolated tom holo complex by treatment with the detergent dodecyl maltoside. it consists of tom40, tom22, and the small tom components, tom6 and tom7. this core complex was also purified directly from mitochondria after solubilization with do ...199910579717
a eukaryotic protein, nop-1, binds retinal to form an archaeal rhodopsin-like photochemically reactive pigment.the nop-1 gene from neurospora crassa is predicted to encode a seven-helix protein exhibiting conservation with the rhodopsins of the archaeon halobacterium salinarum. in the work presented here we have expressed this gene heterologously in the yeast pichia pastoris, obtaining a relatively high yield of 2.2 mg of nop-1 protein/l of cell culture. the expressed protein is membrane-associated and forms with all-trans retinal a visible light-absorbing pigment with a 534 nm absorption maximum and app ...199910571987
a comparison of thermal characteristics and kinetic parameters of trehalases from a thermophilic and a mesophilic fungus.trehalases from a thermophilic fungus thermomyces lanuginosus (m(r) 145 kda) and a mesophilic fungus neurospora crassa (m(r) 437 kda) were purified to compare their thermal characteristics and kinetic constants. both trehalases were maximally active at 50 degrees c, had an acidic ph optimum and were glycoproteins (20% and 43%, w/w, carbohydrate content for t. lanuginosus and n. crassa, respectively). at their temperature optimum, their k(m) was similar (0.57 and 0.52 mm trehalose, for t. lanugin ...199910564806
deletogenic activity of 1,2:7,8-diepoxyoctane in the salmonella typhimurium tester strain ta102.1,2:7,8-diepoxyoctane (deo), whose deletogenic activity was first demonstrated in ad-3 system of neurospora crassa and then in different species, has been tested in salmonella typhimurium tester strain ta102 (hisg428(ochre)). it was confirmed that it is a direct acting mutagen and was found that its activity is stimulated with the s9 mix. obtained his(+) revertants were screened on their response to the histidine analog, n-(2-thiazolyl)-dl-alanine (thiala). thirty-two percent of spontaneous and ...199910556620
comparison of the spectra of genetic damage in formaldehyde-induced ad-3 mutations between dna repair-proficient and -deficient heterokaryons of neurospora crassa.the mutagenic effects of formaldehyde (fa) have been compared in dna repair-proficient (heterokaryon 12) and dna repair-deficient (heterokaryon 59) two-component heterokaryons of neurospora crassa. the data from forward-mutation experiments were used to compare the spectra of fa-induced specific-locus mutations at two closely linked loci in the adenine-3 (ad-3) region and on the fa-induced inactivation of heterokaryotic conidia. previous studies have demonstrated that specific-locus mutations at ...199910556619
ionizing radiation-induced mutagenesis: radiation studies in neurospora predictive for results in mammalian cells.ionizing radiation was the first mutagen discovered and was used to develop the first mutagenicity assay. in the ensuing 70+ years, ionizing radiation became a fundamental tool in understanding mutagenesis and is still a subject of intensive research. frederick de serres et al. developed and used the neurospora crassa ad-3 system initially to explore the mutagenic effects of ionizing radiation. using this system, de serres et al. demonstrated the dependence of the frequency and spectra of mutati ...199910556618
dna repair and specific-locus mutagenesis in neurospora crassa. 199910556617
the entomopathogenic fungus metarhizium anisopliae alters ambient ph, allowing extracellular protease production and activity.ambient ph regulates the expression of virulence genes of metarhizium anisopliae, but it was unknown if m. anisopliae can regulate ambient ph. mutants of m. anisopliae altered in production of oxalic acid were evaluated for the interrelationship of ambient ph, buffering capacity added to media, growth, and generation of extracellular proteases and ammonia. wild-type and acid-overproducing mutants [acid(+)] grew almost as well at ph 8 as at ph 6, but acid-non-producing [acid(-)] mutants showed li ...199910537191
involvement of protein kinase c in the response of neurospora crassa to blue light.as a first step towards understanding the process of blue light perception, and the signal transduction mechanisms involved, in neurospora crassa we have used a pharmacological approach to screen a wide range of second messengers and chemical compounds known to interfere with the activity of well-known signal transducing molecules in vivo. we tested the influence of these compounds on the induction of the al-3 gene, a key step in light-induced carotenoid biosynthesis. this approach has implicate ...199910517328
deletion of the trichodiene synthase gene of fusarium venenatum: two systems for repeated gene deletions.the trichodiene synthase (tri5) gene of fusarium venenatum was cloned from a genomic library. vectors were created in which the tri5 coding sequence was replaced with the neurospora crassa nitrate reductase (nit3) gene and with the aspergillus nidulans acetamidase (amds) gene flanked by direct repeats. the first vector was utilized to transform a nitrate reductase (niad) mutant of f. venenatum to prototrophy, and the second vector was utilized to confer acetamide utilization to the wild-type str ...199910512673
microscopic analysis of neurospora ropy mutants defective in nuclear distribution.movement and distribution of nuclei in fungi has been shown to be dependent on microtubules and the microtubule-associated motor cytoplasmic dynein. neurospora crassa mutants known as ropy are defective in nuclear distribution. we have shown that three of the ro genes, ro-1, ro-3, and ro-4, encode subunits of either cytoplasmic dynein or the dynein activator complex, dynactin. three other ro genes, ro-7, ro-10, and ro-11, are required for the integrity or localization of cytoplasmic dynein or dy ...199910512672
characterization of a neurospora crassa photolyase-deficient mutant generated by repeat induced point mutation of the phr gene.we produced a photolyase-deficient mutant by repeat induced point mutation using the neurospora crassa photolyase gene cloned previously. this mutation identified a new gene, phr, which was mapped on the right arm of linkage group i by both rflp mapping and conventional mapping. to investigate the relationship between photoreactivation and dark repair processes, especially excision repair, double mutants of phr with representative repair-defective mutants of different types were constructed and ...199910512668
action of repeat-induced point mutation on both strands of a duplex and on tandem duplications of various sizes in neurospora.in neurospora crassa, dna sequence duplications are detected and altered efficiently during the sexual cycle by a process known as rip (repeat-induced point mutation). affected sequences are subjected to multiple gc-to-at mutations. to explore the pattern in which base changes are laid down by rip we examined two sets of strains. first, we examined the products of a presumptive spontaneous rip event at the mtr locus. results of sequencing suggested that a single rip event produces two distinct p ...199910511550
circadian biology: clocks for the real world.the circadian system of neurospora crassa includes a molecular feedback loop that is entrainable by light. a recent study has shown that a second, elusive oscillator interacts with the feedback loop to drive output rhythms.199910508572
characterization of a mammalian homolog of the gcn2 eukaryotic initiation factor 2alpha kinase.in eukaryotic cells, protein synthesis is regulated in response to various environmental stresses by phosphorylating the alpha subunit of the eukaryotic initiation factor 2 (eif2alpha). three different eif2alpha kinases have been identified in mammalian cells, the heme-regulated inhibitor (hri), the interferon-inducible rna-dependent kinase (pkr) and the endoplasmic reticulum-resident kinase (perk). a fourth eif2alpha kinase, termed gcn2, was previously characterized from saccharomyces cerevisia ...199910504407
the nit2 nitrogen regulatory protein of neurospora: expression and stability of nit-2 mrna and protein.in neurospora crassa, nit2 is a global transcription factor that positively regulates the expression of up to 100 genes that are related to nitrogen metabolism. nit2 is responsible for the lifting of nitrogen catabolite repression when the cellular levels of glutamine or other favored nitrogen sources become limited. immunoprecipitation of the nit2 protein showed that it is constitutively expressed, although its expression level is elevated a few-fold when nitrate instead of glutamine is used as ...199910501938
characterization of neurospora crassa mutants isolated following repeat-induced point mutation of the beta subunit of fatty acid synthase.neurospora crassa cel-2 mutants were isolated following repeat-induced point mutation using part of the gene encoding beta-fatty acid synthase. these mutants are phenotypically less leaky than cel-1, which has a defective alpha-fatty acid synthase. the cel-2 mutant had a strict fatty acid (16:0) requirement for growth, and synthesized less fatty acid de novo than cel-1. unlike cel-1, cel-2 has impaired fertility, and homozygous crosses are infertile, suggesting a low but strict requirement for f ...199910501937
inactivation of the neurospora crassa mitochondrial outer membrane protein tom70 by repeat-induced point mutation (rip) causes defects in mitochondrial protein import and morphology.mitochondrial biogenesis requires the efficient import of hundreds of different cytosolically translated preproteins into existing organelles. recognition and translocation of preproteins at the mitochondrial outer membrane is achieved by the tom complex (translocase of the outer mitochondrial membrane). the largest component of this complex is tom70, an integral outer membrane protein with a large cytosolic domain thought to serve as a receptor for a specific group of preproteins. to investigat ...199910501936
the nadp-dependent glutamate dehydrogenase gene from penicillium chrysogenum and the construction of expression vectors for filamentous fungi.the gdha gene encoding the nadp-dependent glutamate dehydrogenase activity from penicillium chrysogenum has been isolated and characterized for its use in gene expression. the nucleotide sequence of a 2816-bp genomic fragment was determined, showing an open reading frame of 1600 bp interrupted by two introns, of 160 bp and 57 bp respectively, with fungal consensus splice-site junctions. the predicted amino acid sequence revealed a high degree of identity to glutamate dehydrogenase enzymes, espec ...199910499259
a reductase/isomerase subunit of mitochondrial nadh:ubiquinone oxidoreductase (complex i) carries an nadph and is involved in the biogenesis of the complex.respiratory chains of bacteria and mitochondria contain closely related forms of the proton-pumping nadh:ubiquinone oxidoreductase, or complex i. the bacterial complex i consists of 14 subunits, whereas the mitochondrial complex contains some 25 extra subunits in addition to the homologues of the bacterial subunits. one of these extra subunits with a molecular mass of 40 kda belongs to a heterogeneous family of reductases/isomerases with a conserved nucleotide binding site. we deleted this subun ...199910497022
complementation between mitochondrial processing peptidase (mpp) subunits from different species.mitochondrial processing peptidase (mpp), a dimer of nonidentical subunits, is the primary peptidase responsible for the removal of leader peptides from nuclearly encoded mitochondrial proteins. alignments of the alpha and beta subunits of mpp (alpha- and beta-mpp) from different species show strong protein sequence similarity in certain regions, including a highly negatively charged region as well as a domain containing a putative metal ion binding site. in this report, we describe experiments ...199910496979
the 24-kda iron-sulphur subunit of complex i is required for enzyme activity.we have cloned the nuclear gene encoding the 24-kda iron-sulphur subunit of complex i from neurospora crassa. the gene was inactivated in vivo by repeat-induced point-mutations, and mutant strains lacking the 24-kda protein were isolated. mutant nuo24 appears to assemble an almost intact complex i only lacking the 24-kda subunit. however, we also found reduced levels of the nadh-binding, 51-kda subunit of the enzyme. surprisingly, the complex i from the nuo24 strain lacks nadh:ferricyanide reduc ...199910491161
repeated ubiquitin genes in trichophyton mentagrophytes.using trichophyton mentagrophytes cdna as a template, we performed pcr amplification with the ub1s and ub1r primers for isolation of a partial fragment of t. mentagrophytes ubiquitin gene. we screened the t. mentagrophytes cdna library prepared with uni-zap phage vector by hybridization with the t. mentagrophytes ubiquitin fragment, ub1s-ub1r. the nucleotide and deduced amino acid sequences of t. mentagrophytes ubiquitin gene encoded two ubiquitin repeats in 162 bp to 624 bp. the deduced amino a ...199910489441
role of a white collar-1-white collar-2 complex in blue-light signal transduction.mutations in either white collar-1 (wc-1) or white collar-2 (wc-2) lead to a loss of most blue-light-induced phenomena in neurospora crassa. sequence analysis and in vitro experiments show that wc-1 and wc-2 are transcription factors regulating the expression of light-induced genes. the wc proteins form homo- and heterodimers in vitro; this interaction could represent a fundamental step in the control of their activity. we demonstrate in vivo that the wc proteins are assembled in a white collar ...199910487748
primary structure and characterisation of a 64 kda nadh dehydrogenase from the inner membrane of neurospora crassa mitochondria.a cdna clone encoding a mitochondrial nadh dehydrogenase from neurospora crassa was sequenced. the total dna sequence encompasses 2570 base pairs and contains an open reading frame of 2019 base pairs coding for a precursor polypeptide of 673 amino acid residues. the protein is encoded by a single-copy gene located to the right side of the centromere in linkage group iv of the fungal genome. the n-terminus of the precursor protein has characteristics of a mitochondrial targeting pre-sequence. the ...199910482790
effects of disrupting the 21 kda subunit of complex i from neurospora crassa.we have cloned and inactivated in vivo, by repeat-induced point mutations, the nuclear gene encoding a 21 kda subunit of complex i from neurospora crassa. mitochondria from the nuo21 mutant lack this specific protein but retain other subunits of complex i in approximately normal amounts. in addition, this mutant is able to assemble an almost intact enzyme. the electron transfer activities from nadh to artificial acceptors of mitochondrial membranes from nuo21 differ from those of the wild-type s ...199910477266
ambient ph signal transduction in aspergillus: completion of gene characterization.completing the molecular analysis of the six pal genes of the ambient ph signal transduction pathway in aspergillus nidulans, we report the characterization of palc and palh. the derived translation product of palh contains 760 amino acids with prediction of seven transmembrane domains in its n-terminal moiety. remarkably, a palh frameshift mutant lacking just over half the palh protein, including almost all of the long hydrophilic region c-terminal to the transmembrane domains, retains some pal ...199910476033
bioelectrorheological model of the cell. 8. cellular deformation under prolonged and recurrent shear stress.the influence of a prolonged and recurrent shear stress created by a periodic electric field on the mechanical properties of neurospora crassa cells was investigated. conditions were found under which modifications of cellular structures responding to stress become irreversible, and plastic flow of the viscoelastic structural elements is observed. the symmetry of the response of the cell under stress application and relaxation was lost, when compared to the reference conditions. to interpret the ...200810474657
the antibiotic viomycin as a model peptide for the origin of the co-evolution of rna and proteins.viomycin is an rna-binding peptide antibiotic which inhibits prokaryotic protein synthesis and group i intron self-splicing. this antibiotic enhances the activity of the ribozyme derived from the neurospora crassa vs rna, and at sub-inhibitory concentrations it induces the formation of group i intron oligomers. here, we address the question whether viomycin exerts specificity in the promotion of rna-rna interactions. in an in vitro selection experiment we tested the ability of viomycin to specif ...199910472628
the tama protein fused to a dna-binding domain can recruit area, the major nitrogen regulatory protein, to activate gene expression in aspergillus nidulans.the area gene of aspergillus nidulans encodes a gata zinc finger transcription factor that activates the expression of a large number of genes subject to nitrogen metabolite repression. the amount and activity of the area protein under different nitrogen conditions is modulated by transcriptional, post-transcriptional, and post-translational controls. one of these controls of area activity has been proposed to involve the nmra protein interacting with the dna-binding domain and the extreme c ter ...199910471703
gene silencing: rna makes rna makes no protein.a mutation that disrupts post-transcriptional gene silencing in neurospora crassa has been found to affect the homologue of a plant-encoded rna-dependent rna polymerase. this enzyme may produce a specificity determinant of gene silencing and mediate an epigenetic conversion at the rna level.199910469584
kinesin and dynein mutants provide novel insights into the roles of vesicle traffic during cell morphogenesis in neurospora.kinesin and cytoplasmic dynein are force-generating molecules that move in opposite directions along microtubules. they have been implicated in the directed transport of a wide variety of cellular organelles, but it is unclear whether they have overlapping or largely independent functions.201610469561
polymorphism around cog extends into adjacent structural genes.the recombination hotspot cog overlaps a highly polymorphic 950-bp region of linkage group i in neurospora crassa. the sequence of this region in the four strains, lindegren 25a, lindegren a, emerson a and st. lawrence 74a, each differs from the others by 1.4% or more. comparison of the sequence of st. lawrence 74a and lindegren 25a each side of cog shows a high level of sequence heterology extending in both directions, including the coding sequences for his-3 and a putative gene lpl with homolo ...199910467008
searching for the role of protein phosphatases in eukaryotic microorganisms.preference for specific protein substrates together with differential sensitivity to activators and inhibitors has allowed classification of serine/threonine protein phosphatases (pps) into four major types designated types 1, 2a, 2b and 2c (pp1, pp2a, pp2b and pp2c, respectively). comparison of sequences within their catalytic domains has indicated that pp1, pp2a and pp2b are members of the same gene family named ppp. on the other hand, the type 2c enzyme does not share sequence homology with t ...199910454741
repair of apurinic/apyrimidinic sites by uv damage endonuclease; a repair protein for uv and oxidative damage.uv damage endonuclease (uvde) initiates a novel form of excision repair by introducing a nick imme-diately 5" to uv-induced cyclobutane pyrimidine dimers or 6-4 photoproducts. here, we report that apurinic/apyrimidinic (ap) sites are also nicked by neurospora crassa and schizosaccharomyces pombe uvde. uvde introduces a nick immediately 5" to the ap site leaving a 3"-oh and a 5"-phosphate ap. apyrimidinic sites are more effectively nicked by uvde than apurinic sites. uvde also possesses 3"-repair ...199910454605
functional anatomy of the kinesin molecule in vivo.we have developed an assay that allows the functional efficiency of mutant kinesins to be probed in vivo. we show here that the growth rate of the filamentous fungus neurospora crassa can be used as a sensitive reporter for the ability of mutant kinesins to suppress the phenotype of the kinesin null mutant of neurospora. truncation mutants, internal deletion mutants and chimeras, in which homologous domains were exchanged between different fungal kinesins, were generated and transformed into the ...199910449406
a mutation within the catalytic domain of cot1 kinase confers changes in the presence of two cot1 isoforms and in ser/thr protein kinase and phosphatase activities in neurospora crassa.neurospora crassa grows by forming spreading colonies. cot-1 belongs to a class of n. crassa colonial temperature-sensitive (cot) mutants and encodes a ser/thr protein kinase. we have mapped the cot-1 mutation to a single base change resulting in a his to arg substitution at amino acid 351, which resides within the catalytic domain. antibodies raised against cot1 detected and immunoprecipitated a predominant 73-kda polypeptide in n. crassa extracts, whose abundance was constant under all growth ...200910441452
nucleotide binding and hydrolysis properties of neurospora crassa cytosolic molecular chaperones, hsp70 and hsp80, heat-inducible members of the eukaryotic stress-70 and stress-90 families.formation of a hetero-oligomeric complex between hsp70 and hsp80 of neurospora crassa was observed previously by means of chemical crosslinking and enzyme-linked immunosorbent assays (elisa). the present study documents the effect of nucleotides on the subunit structure of hsp70 and hsp80 by crosslinking with bifunctional reagents: glutaraldehyde, dimethyl adipimidate (dma), and dimethyl suberimidate (dms). the inter-protomer crosslinking of hsp80 with dma and dms was suppressed by atp and to a ...199910438143
physical properties and heavy metal uptake of encapsulated escherichia coli expressing a metal binding gene (ncp).a recombinant escherichia coli expressing the neurospora crassa metallothionein gene (ncp) has previously been shown to remove low levels of cd and other metals from solution. for further development as a biosorbent, the encapsulation of the ncp is investigated by various matrices. the ncp was encapsulated in alginate, chitosan-alginate or kappa-carrageenan, and its physical properties characterized. results indicated that encapsulation in alginate resulted in fragile beads, whereas encapsulatio ...199910420333
the erg-3 (sterol delta14,15-reductase) gene of neurospora crassa: generation of null mutants by repeat-induced point mutation and complementation by proteins chimeric for human lamin b receptor sequences.null mutations were generated in the erg-3 gene of neurospora crassa by repeat-induced point mutation (rip). the mutants were viable, lacked ergosterol, were resistant to the steroidal glycoside alpha-tomatine and were sensitive to the phytoalexins pisatin and biochanin a. rip was frequently associated with silencing of the hph gene located adjacent to the duplicated erg-3 sequence. the silencing of hph was reversible in the two cases examined and appeared to be due to the spread of cytosine met ...199910411271
flocculation of hyphae is associated with a deletion in the putative cahk1 two-component histidine kinase gene from candida albicans.in candida albicans, three putative histidine kinase genes have been described thus far, including casln1, canik1/cos1 and cahk1. the encoded proteins for c. albicans, casln1p and canik1p, which are similar to sln1p from saccharomyces cerevisiae and nik-1 from neurospora crassa, seem to function in osmoregulation and morphogenesis, respectively. recently, the isolation of cahk1, a putative histidine kinase gene from c. albicans has been reported. in addition to the histidine and aspartyl domains ...199910411270
singlet oxygen is part of a hyperoxidant state generated during spore germination.we show that singlet oxygen is generated in asexual spores (conidia) from neurospora crassa at the onset of germination. oxidation of n. crassa catalase-1 (cat-1) was previously shown to be caused by singlet oxygen (lledías et al. j. biol. chem. 273, 1998). in germinating conidia, increased protein oxidation, decrease of total protein, cat-1 oxidation and accumulation of cat-1 mrna was detected. these changes were modulated in vivo by light intensity, an external clean source of singlet oxygen, ...199910401603
comparison of h+-atpase and ca2+-atpase suggests that a large conformational change initiates p-type ion pump reaction cycles.structures have recently been solved at 8 a resolution for both ca2+-atpase from rabbit sarcoplasmic reticulum and h+-atpase from neurospora crassa. these cation pumps are two distantly related members of the family of p-type atpases, which are thought to use similar mechanisms to generate atp-dependent ion gradients across a variety of cellular membranes. we have undertaken a detailed comparison of the two structures in order to describe their similarities and differences as they bear on their ...199910395538
the drosophila melanogaster gene for the nadh:ubiquinone oxidoreductase acyl carrier protein: developmental expression analysis and evidence for alternatively spliced forms.we have isolated the drosophila melanogaster gene encoding the mitochondrial acyl carrier protein (mtacp), a subunit of nadh:ubiquinone oxidoreductase involved in de novo fatty acid synthesis in the mitochondrion. this gene expresses two distinct mature transcripts by alternative splicing, which encode mature polypeptides of 86 (mtacp1a) and 88 (mtacp1b) amino acids, respectively. drosophila mtacp1 is 72% identical to mammalian mtacp, 47% identical to arabidopsis thaliana mtacp, and 46% identica ...199910394906
transcription of the avirulence gene avr9 of the fungal tomato pathogen cladosporium fulvum is regulated by a gata-type transcription factor in aspergillus nidulans.the avirulence gene avr9 of the fungal tomato pathogen cladosporium fulvum is highly induced during infection of tomato plants. expression of the avr9 gene can also be induced in vitro when cells are grown on synthetic liquid medium containing little or no nitrogen. the avr9 promoter contains six copies of the sequence tagata and six additional copies of the core sequence gata within 0.4 kb upstream of the translation start site. in the filamentous fungi aspergillus nidulans and neurospora crass ...199910394902
the nop-1 gene of neurospora crassa encodes a seven transmembrane helix retinal-binding protein homologous to archaeal rhodopsins.opsins are a class of retinal-binding, seven transmembrane helix proteins that function as light-responsive ion pumps or sensory receptors. previously, genes encoding opsins had been identified in animals and the archaea but not in fungi or other eukaryotic microorganisms. here, we report the identification and mutational analysis of an opsin gene, nop-1, from the eukaryotic filamentous fungus neurospora crassa. the nop-1 amino acid sequence predicts a protein that shares up to 81.8% amino acid ...199910393943
assaying rna chaperone activity in vivo using a novel rna folding trap.in the absence of proteins, rnas often misfold in vitro due to alternative base pairings which result from the molecule being trapped in inactive conformations. we identify an in vivo folding trap in the t4 phage td gene, caused by nine base pairs between a sequence element in the upstream exon of the td gene and another at the 3' end of the intron. during translation, the ribosome resolves this interaction; consequently the intron folds correctly and splicing occurs. the introduction of a stop ...199910393192
evidence for negative interference: clustering of crossovers close to the am locus in neurospora crassa among am recombinants.in response to a conflict between two mapping studies in the predicted orientation of the allele map with respect to the centromere, fincham proposed that recombination events at the neurospora am locus rarely have an associated crossover. fincham considered that the elevated levels of crossing over between flanking markers in am recombinants resulted from negative interference, an increased probability of a nearby second event, and on this basis predicted a clustering of crossing over near am i ...199910388816
a single external enzyme confers alternative nadh:ubiquinone oxidoreductase activity in yarrowia lipolytica.nadh:ubiquinone oxidoreductases catalyse the first step within the diverse pathways of mitochondrial nadh oxidation. in addition to the energy-conserving form commonly called complex i, fungi and plants contain much simpler alternative nadh:ubiquinone oxido-reductases that catalyze the same reaction but do not translocate protons across the inner mitochondrial membrane. little is known about the distribution and function of these enzymes. we have identified ylndh2 as the only gene encoding an al ...199910381390
assignment of circadian function for the neurospora clock gene frequency.circadian clocks consist of three elements: entrainment pathways (inputs), the mechanism generating the rhythmicity (oscillator), and the output pathways that control the circadian rhythms. it is difficult to assign molecular clock components to any one of these elements. experiments show that inputs can be circadianly regulated and outputs can feed back on the oscillator. mathematical simulations indicate that under- or overexpression of a gene product can result in arrhythmicity, whether the p ...199910376598
pagrg1, a glucose-repressible gene of podospora anserina that is differentially expressed during lifespan.a loss-of-function mutation in grisea, a gene of podospora anserina that was previously shown to code for a copper-modulated transcription factor, leads to a significant increase in lifespan. in an attempt to identify and to isolate potential target genes controlled by grisea, a rt-differential-display screen was performed. this approach resulted in the identification of a gene, pagrg1, that is differentially expressed in the wild-type and in the long-lived grisea mutant. in the mutant, transcri ...199910369964
hyperornithinaemia-hyperammonaemia-homocitrullinuria syndrome is caused by mutations in a gene encoding a mitochondrial ornithine transporter.neurospora crassa arg13 and saccharomyces cerevisiae arg11 encode mitochondrial carrier family (mcf) proteins that transport ornithine across the mitochondrial inner membrane. we used their sequences to identify est candidates that partially encode orthologous mammalian transporters. we thereby identified such a gene (ornt1) that maps to 13q14 and whose expression, similar to that of other urea cycle (uc) components, was high in liver and varied with changes in dietary protein. ornt1 expression ...199910369256
identification of a 24 kda intrinsic membrane protein from mammalian peroxisomes.a 24 kda protein from rat liver peroxisomal membrane was isolated and subjected to edman degradation. using the n-terminal sequence of this polypeptide we have identified several rat and human expressed sequence tags in the genbank database. the complete sequence of a human cdna clone was determined. the open reading frame encodes an extremely basic protein 212 amino acid residues long. a high similarity between this mammalian protein and hypothetical proteins from caenorhabditis elegans and neu ...199910366717
neurospora crassa ro-10 and ro-11 genes encode novel proteins required for nuclear distribution.movement and distribution of nuclei in fungi have been shown to be dependent on cytoplasmic microtubules and the microtubule-associated motor cytoplasmic dynein. we have isolated hundreds of neurospora crassa mutants, known as ropy, that are defective in nuclear distribution. three of the ro genes, ro-1, ro-3 and ro-4, have been shown to encode subunits of either cytoplasmic dynein or the dynein activator complex, dynactin. in this report, we describe the isolation and initial characterization o ...199910361308
carbon regulation of ribosomal genes in neurospora crassa occurs by a mechanism which does not require cre-1, the homologue of the aspergillus carbon catabolite repressor, crea.transcription of the ribosomal protein and 40s rrna genes is coordinately regulated during steady state growth and carbon shifts in neurospora crassa. recognition sequences for the aspergillus nidulans carbon catabolite repressor, crea, overlap transcriptional elements of a 40s rrna gene and the crp-2 ribosomal protein gene. they also occur in similar locations in the promoters of several other ribosomal protein genes. substitutions encompassing the -74 and -167 crea consensus sequences in the c ...199910361038
molecular mechanisms of chromosomal rearrangement in fungi.both sexual and asexual fungi undergo chromosomal rearrangements, which are the main cause of karyotype variability among the populations. different recombination processes can produce chromosomal reorganizations, both during mitosis and meiosis, but other mechanisms operate to limit the extent of the rearrangements; some of these mechanisms, such as the rip (repeat-induced point mutations) of neurospora crassa, have been well established for sexual fungi. in laboratory strains, treatments such ...199910342097
the structure of the vacuolar atpase in neurospora crassa.the filamentous fungus neurospora crassa contains many small vacuoles. these organelles contain high concentrations of polyphosphates and basic amino acids, such as arginine and ornithine. because of their size and density, the vacuoles can be separated from other organelles in the cell. the atp-driven proton pump in the vacuolar membrane is a typical v-type atpase. we examined the size and structure of this enzyme using radiation inactivation and electron microscopy. the vacuolar atpase is a la ...199910340846
molecular cloning and characterization of ct-pkar, a gene encoding the regulatory subunit of camp-dependent protein kinase in colletotrichum trifolii.colletotrichum trifolii is a plant pathogenic fungus causing alfalfa anthracnose. prepenetration development, including conidial germination and appressorial formation, are requisite for successful infection. pharmacological data from our laboratory indicated a role for a camp-dependent protein kinase (pka) pathway during these early morphogenic transitions. thus, the cloning and characterization of the genes for pka catalytic and regulatory subunits were undertaken to more precisely determine t ...199910339807
gene silencing in neurospora crassa requires a protein homologous to rna-dependent rna polymerase.in plants and fungi, the introduction of transgenes can lead to post-transcriptional gene silencing. this phenomenon, in which expression of the transgene and of endogenous genes containing sequences homologous to the transgene can be blocked, is involved in virus resistance and genome maintenance. transgene-induced gene silencing has been termed quelling in neurospora crassa and co-suppression in plants. quelling-defective (qde) mutants of n. crassa, in which transgene-induced gene silencing is ...199910335848
signal presequences increase mitochondrial permeability and open the multiple conductance channel.we have reported that the signal presequence of cytochrome oxidase subunit iv from neurospora crassa increases the permeability of isolated rat liver mitochondria [p. m. sokolove and k. w. kinnally (1996) arch. biochem. biophys. 336, 69] and regulates the behavior of the mutiple conductance channel (mcc) of yeast inner mitochondrial membrane [t. a. lohret and k. w. kinnally (1995) j. biol. chem. 270, 15950]. here we examine in greater detail the action of a number of mitochondrial presequences f ...199910334870
interaction of mitochondrial presequences with dnak and mitochondrial hsp70.mitochondrial heat shock protein 70 (mt-hsp70) functions as a molecular chaperone in mitochondrial biogenesis. the chaperone in co-operation with its co-proteins acts as a translocation motor pulling the mitochondrial precursor into the matrix. mt-hsp70s are highly conserved when compared to the bacterial hsp70 homologue, dnak. here we have used dnak as a model to study the interaction of mitochondrial presequences with mt-hsp70 applying a dnak-binding algorithm, computer modeling and biochemica ...199910329135
nad+-dependent glutamate dehydrogenase of the edible mushroom agaricus bisporus: biochemical and molecular characterization.the nad+-dependent glutamate dehydrogenase (nad-gdh) of agaricus bisporus, a key enzyme in nitrogen metabolism, was purified to homogeneity. the apparent molecular mass of the native enzyme is 474 kda comprising four subunits of 116 kda. the isoelectric point of the enzyme is about 7.0. km values for ammonium, 2-oxoglutarate, nadh, glutamate and nad+ were 6.5, 3.5, 0.06, 37.1 and 0.046 mm, respectively. the enzyme is specific for nad(h). the gene encoding this enzyme (gdhb) was isolated from an ...199910323225
neutral trehalases catalyse intracellular trehalose breakdown in the filamentous fungi aspergillus nidulans and neurospora crassa.a camp-activatable ca2+-dependent neutral trehalase was identified in germinating conidia of aspergillus nidulans and neurospora crassa. using a pcr approach, a. nidulans and n. crassa genes encoding homologues of the neutral trehalases found in several yeasts were cloned and sequenced. disruption of the antreb gene encoding a. nidulans neutral trehalase revealed that it is responsible for intracellular trehalose mobilization at the onset of conidial germination, and that this phenomenon is part ...199910320571
a common ancestor for a subunit in the mitochondrial proton-translocating nadh:ubiquinone oxidoreductase (complex i) and short-chain dehydrogenases/reductases.the proton-translocating nadh:ubiquinone oxidoreductase or complex i is located in the inner membranes of mitochondria, where it catalyzes the transfer of electrons from nadh to ubiquinone. here we report that one of the subunits in complex i is homologous to short-chain dehydrogenases and reductases, a family of enzymes with diverse activities that include metabolizing steroids, prostaglandins and nucleotide sugars. we discovered that a subunit of complex i in human, cow, neurospora crassa and ...199910228558
copper- and zinc-containing superoxide dismutase and its gene from candida albicans.cytosolic copper- and zinc-containing superoxide dismutase was purified 136-fold with an overall yield of 2.5% to apparent electrophoretic homogeneity from the dimorphic pathogenic fungus, candida albicans. the molecular mass of the native enzyme was 39.4 kda and the enzyme was composed of two identical subunits with a molecular mass of 19.6 kda. the enzyme was stable in the range of ph 4.0-9.0 and up to 55 degrees c. the ultraviolet-visible absorption spectrum of the enzyme showed the absorptio ...199910216241
characterisation of the last fe-s cluster-binding subunit of neurospora crassa complex i.we have cloned cdnas encoding the last iron-sulphur protein of complex i from neurospora crassa. the cdna sequence contains an open reading frame that codes for a precursor polypeptide of 226 amino acid residues with a molecular mass of 24972 da. our results indicate that the mature protein belongs probably to the peripheral arm of complex i and is rather unstable when not assembled into the enzyme. the protein is highly homologous to the psst subunit of bovine complex i, the most likely candida ...199910216160
functional analysis of the two zinc fingers of sre, a gata-type factor that negatively regulates siderophore synthesis in neurospora crassa.multiple gata factors, zinc finger dna binding proteins that recognize consensus gata elements, exist in neurospora crassa. one of them, sre, is involved in controlling the iron metabolic pathway of n. crassa. in n. crassa, iron transport is mediated by a number of small cyclic peptides, known as siderophores. the siderophore synthesis pathway is negatively regulated by sre; a loss-of-function sre mutant strain showed partial constitutive synthesis of siderophore. in the research presented here, ...199910194352
the ukc1 gene encodes a protein kinase involved in morphogenesis, pathogenicity and pigment formation in ustilago maydis.the fungal phytopathogen ustilago maydis alternates between budding and filamentous growth during its life cycle. this dimorphic transition, which is influenced by environmental factors and mating, is regulated in part by camp-dependent protein kinase (pka). we have recently identified a related protein kinase, encoded by the ukc1 gene, that also plays a role in determining cell shape. the ukc1 gene is homologous to several other protein kinase-encoding genes including the cot-i gene of neurospo ...199910102363
physiological consequence of disruption of the vma1 gene in the riboflavin overproducer ashbya gossypii.the vacuolar atpase subunit a structural gene vma1 of the biotechnologically important riboflavin overproducer ashbya gossypii was cloned and disrupted to prevent riboflavin retention in the vacuolar compartment and to redirect the riboflavin flux into the medium. cloning was achieved by polymerase chain reaction using oligonucleotide primers derived form conserved sequences of the vma1 proteins from yeast and filamentous fungi. the deduced polypeptide comprises 617 amino acids with a calculated ...199910092625
glucose metabolism in neurospora is altered by heat shock and by disruption of hsp30.we compared the metabolism of [1-13c]glucose by wild type cells of neurospora crassa at normal growth temperature and at heat shock temperatures, using nuclear magnetic resonance analysis of cell extracts. high temperature led to increased incorporation of 13c into trehalose, relative to all other metabolites, and there was undetectable synthesis of glycerol, which was a prominent metabolite of glucose at normal temperature (30 degrees c). heat shock strongly reduced formation of tricarboxylic a ...199910076052
amphotropic murine leukemia virus entry is determined by specific combinations of residues from receptor loops 2 and 4.pit2 is the human receptor for amphotropic murine leukemia virus (a-mulv); the related human protein pit1 does not support a-mulv entry. interestingly, chimeric proteins in which either the n-terminal or the c-terminal part of pit2 was replaced by the pit1 sequence all retained a-mulv receptor function. a possible interpretation of these observations is that pit1 harbors sequences which can specify a-mulv receptor function when presented in a protein context other than pit1, e.g., in pit1-pit2 h ...199910074169
pyruvate decarboxylase filaments are associated with the cortical cytoskeleton of asci and spores over the sexual cycle of filamentous ascomycetes.we show that pyruvate decarboxylase (pdc) 8- to 10-nm-diameter filaments, first described in vegetative cells of neurospora crassa, are ubiquitously present in filamentous fungi. the cellular arrangement of these structures was examined over the entire sexual cycle of the ascomycetes n. crassa, n. tetraesperma, podospora anserina, and sordaria macrospora. pdc-filaments were found associated with the cortical microtubule array of asci and ascospores and absent from the vicinity of spindles and sp ...199910072321
positive regulation of adenylyl cyclase activity by a galphai homolog in neurospora crassa.gna-1 and gna-2 are two g protein alpha subunits from the filamentous fungus neurospora crassa. loss of gna-1 leads to multiple phenotypes, while deltagna-2 strains do not exhibit visible defects. however, deltagna-1deltagna-2 mutants are more affected in deltagna-1 phenotypes. here we report a biochemical investigation of the roles of gna-1 and gna-2 in camp metabolism. assays of mg2+ atp-dependent adenylyl cyclase activity (+/-gppnhp) in extracts from submerged cultures indicated that deltagna ...199910072319
microconidia of neurospora crassa.neurospora crassa produces two types of vegetative spores-relatively small numbers of uninucleate microconidia and very large numbers of multinucleate macroconidia (blastoconidia and arthroconidia). the microconidia can function either as spermatia (male gametes) or as asexual reproductive structures or both. in nature they probably function exclusively in fertilization of protoperithecia. the environmental conditions favoring their formation and the pattern of their development are quite distin ...199910072316
isolation, characterization and disruption of the area nitrogen regulatory gene of gibberella fujikuroi.the gene area-gf, a homologue of the major nitrogen regulatory genes nit-2, area, nre and nut1 of neurospora crassa, aspergillus nidulans, penicillium chrysogenum and magnaporthe grisea, respectively, was cloned from the gibberellin (ga)-producing rice pathogen gibberella fujikuroi. area-gf encodes a protein of 972 amino acid residues which contains a single putative zinc finger dna-binding domain that is at least 98% identical to the zinc finger domains of the homologous fungal proteins. the ar ...199910071216
the wd protein cpc2p is required for repression of gcn4 protein activity in yeast in the absence of amino-acid starvation.the cpc2 gene of the budding yeast saccharomyces cerevisiae encodes a g beta-like wd protein which is involved in regulating the activity of the general control activator gcn4p. the cpc2 gene encodes a premrna which is spliced and constitutively expressed in the presence or absence of amino acids. loss of cpc2 gene function suppresses a deletion of the gcn2 gene encoding the general control sensor kinase, but not a deletion in the gcn4 gene. the resulting phenotype has resistance against amino-a ...199910048025
the goodwin model: simulating the effect of cycloheximide and heat shock on the sporulation rhythm of neurospora crassa.the goodwin model is a negative feedback oscillator which describes rather closely the putative molecular mechanism of the circadian clock of neurospora and drosophila. an essential feature is that one or two clock proteins are synthesized and degraded in a rhythmic fashion. when protein synthesis in n. crassa (wild-type frq+and long-period mutant frq7) was inhibited by continuous incubation with increasing concentrations of cycloheximide (chx) the period of the circadian sporulation rhythmicity ...199910036201
cloning of two genes encoding potassium transporters in neurospora crassa and expression of the corresponding cdnas in saccharomyces cerevisiae.two neurospora crassa genes, trk-1 and hak-1, encode k+ transporters that show sequence similarities to the trk transporters described in saccharomyces cerevisiae and schizosaccharomyces pombe, and to the hak transporters described in schwanniomyces occidentalis and barley. the n. crassa trk1 and hak1 transporters expressed by the corresponding cdnas in a trk1 delta trk2 delta mutant of s. cerevisiae exhibited a high affinity for rb+ and k+. northern blot analysis and comparison of the kinetic c ...199910027968
the aspergillus nidulans gata factor srea is involved in regulation of siderophore biosynthesis and control of iron uptake.a gene encoding a new gata factor from aspergillus nidulans, srea, was isolated and characterized. srea displays homology to two fungal regulators of siderophore biosynthesis: about 30% overall identity to sre from neurospora crassa and about 50% identity to urbs1 from ustilago maydis over a stretch of 200 amino acid residues containing two gata-type zinc finger motifs and a cysteine-rich region. this putative dna binding domain, expressed as a fusion protein in escherichia coli, specifically bi ...19999988696
the b regulatory subunit of protein phosphatase 2a is required for completion of macroconidiation and other developmental processes in neurospora crassa.rgb-1, encoding the tentative b regulatory subunit of the type 2a ser/thr phosphatase in neurospora crassa, was isolated from cdna and genomic libraries. based on analysis of cdna and genomic clones, rgb-1 is 3387 nucleotides in length, contains seven putative introns and encodes a 461-amino-acid polypeptide. intron i, which is 5' to the presumed translation initiation codon, contains a uorf encoding 34 amino acids. intron vi undergoes alternative splicing. inactivation of rgb-1 by the repeat-in ...19999987122
cloning and expression of the cdna encoding an alternative oxidase gene from aspergillus niger wu-2223l.a cdna fragment encoding the mitochondrial alternative oxidase, the enzyme responsible for cyanide-insensitive and salicylhydroxamic acid (sham)-sensitive respiration, from the citric acid-producing fungus aspergillus niger wu-2223l was cloned and expressed in escherichia coli as a host strain. synthetic primers were designed from the conserved nucleotide sequences of the alternative oxidase genes from higher plants and a yeast. the 210-bp dna fragment was amplified by pcr with these primers usi ...19999933359
molecular characterization of tol, a mediator of mating-type-associated vegetative incompatibility in neurospora crassa.the mating-type locus in the haploid filamentous fungus, neurospora crassa, controls mating and sexual development. the fusion of reproductive structures of opposite mating type, a and a, is required to initiate sexual reproduction. however, the fusion of hyphae of opposite mating type during vegetative growth results in growth inhibition and cell death, a process that is mediated by the tol locus. mutations in tol are recessive and suppress mating-type-associated heterokaryon incompatibility. i ...19999927450
chitin synthase genes in the arbuscular mycorrhizal fungus glomus versiforme: full sequence of a gene encoding a class iv chitin synthase.chitin synthase genes of the arbuscular mycorrhizal fungus glomus versiforme were sought in an investigation of the molecular basis of fungal growth. three dna fragments (gvchs1, gvchs2 and gvchs3) corresponding to the conserved regions of distinct chitin synthase (chs) genes were amplified by means of the polymerase chain reaction (pcr) with two sets of degenerate primers. gvchs1 and gvchs2 encode two class i chitin synthases, whereas gvchs3 encodes a class iv chitin synthase. a genomic library ...19999919652
search for novel redox groups in mitochondrial nadh:ubiquinone oxidoreductase (complex i) by diode array uv/vis spectroscopy.the proton-translocating nadh:ubiquinone oxidoreductase of mitochondria (complex i) is a large l-shaped multisubunit complex. the peripheral matrix arm contains one fmn and a number of iron-sulfur (fes) clusters and is involved in nadh oxidation and electron transfer to the membrane intrinsic arm. there, following a yet unknown mechanism, the redox-driven proton translocation and the ubiquinone reduction take place. redox groups that would be able to link electron transfer with proton translocat ...19989914816
folylpolyglutamate synthesis in neurospora crassa: primary structure of the folylpolyglutamate synthetase gene and elucidation of the met-6 mutation.in neurospora crassa, the met-6+ gene encodes folylpoly-gamma-glutamate synthetase (fpgs) which catalyzes the formation of polyglutamate forms of folate. methionine auxotrophy of the neurospora crassa met-6 mutant is related to a lesion affecting this enzyme. functional complementation of the mutant strain was achieved by introducing copies of the wild-type met-6+ gene into mutant spheroplasts. the complementing sequences were found to be contained on a 3.5 kb ecori-bamhi restriction fragment. t ...19989887523
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