PMID(sorted descending)
temperature dependence on the delayed fluorescence of chlorophyll a in blue-green algae.1. the delayed fluorescence of chlorophyll a was measured with a phosphoroscope by changing the temperature in a range of room temperatures in intact cells of blue-green algae, anacystis nidulans, two strains of anabaena variabilis and plectonema boryanum, and other kinds of algae, cyanidium caldarium and chlorella pyrenoidosa. the induction of delayed fluorescence remarkably depended on the temperature of measurment. nevertheless, the induction pattern was characterized by three levels of inten ...1977403943
glucan common to the microcyst walls of cyst-forming bacteria.chemical analysis indicated that d-glucose is tha major neutral monosaccharide present in the microcysts of a range of gram-negative bacteria. varying amounts of other neutral sugars were found. the glucose was mainly present as a glucan that could be extracted from microcysts of representative strains with alkali or mild acid treatment. the glucan could be identified as an alpha-1,3-linked polymer on the basis of (i) periodate resistance of the extracted polymer and the material present in micr ...1977402353
growth, glucose metabolism and melanin formation in biotin-deficient aspergillus nidulans.biotin deficiency resulted in an increased growth rate of aspergillus nidulans. the activities of hexokinase and aldolase were not much changed during the growth cycle, but activities of glucose-6-phosphate dehydrogenase and nadp-linked glutamate dehydrogenase increased significantly during the exponential phase. this change was remarkable during biotin deficiency. in contrast to the higher growth rate and respiration rate during biotin deficiency the activities of nad(p)h oxidoreductases were l ...1977402307
protoplasts from aspergillus nidulans.a very effective lytic enzyme system for massive micro/macro-scale production of protoplasts from the filamentous fungus aspergillus nidulans is described. a striking coincidence was observed between maximal lytic activity towards aspergillus mycelium and the presece of both chitinase and alpha-(1 leads to 3)-glucanase activities. the release of protoplasts was greatly enhanced by preincubating the mycelium with 2-deoxy-d-glucose. furthermore, protoplast formation was influenced by fungal age, c ...1979399317
evidence that p-fluorophenylalanine has a direct effect on tubulin in aspergillus nidulans.three temperature-sensitive alleles of bena (bena11, 17 and 21) confer resistance to growth inhibition by p-fluorophenylalanine (fpa). fpa resistance cosegregates with the bena gene. two back-mutations in bena which cause loss of temperature sensitivity cause loss of fpa resistance, and two indirect suppressors of bena temperature sensitivity also cause fpa resistance to be lost. these results indicate that fpa resistance is an intrinsic property of the bena mutations. the intracellular phenylal ...1979396355
phenotypes of double conidiation mutants of aspergillus nidulans.a series of strains, doubly mutant at conidiation loci, have been made. the phenotypes of these strains reflected the epistasy of earlier blocking mutants over later ones and confirmed the order of gene sequence predicted from the phenotypes of single mutants. oligosporogenous mutants gave complex interactions, especially between brl and med mutants. these results indicated that (i) gene action overlapped in time, (ii) several parts of the conidial apparatus were interchangeable and (iii) nuclei ...1979396353
allele specific, gene unspecific suppressors in aspergillus suppressor mutations have been isolated in aspergillus nidulans by coreversion of alleles in physiologically unrelated genes namely, alx, sb, alca, putative structural genes for allantoinase, sulphate permease and alcohol dehydrogenase respectively. the suppressors are allele specific, gene unspecific. those described map in four loci, suaa, b, c, d. suaa and suab are on linkage group iii, suac and suad on vii. suab111, suad103 and suad108 are semi-dominant in their suppression of alx4 and ...1979395416
detection of 5-amino-4-imidazole-n-succinocarboxamide ribotide and hypoxanthine accumulation. a simple method for identification of some purine auxotrophs. 1979395166
allele specific and locus non-specific suppressors in aspergillus nidulans.using n-methyl-n'-nitro-n-nitrosoguanidine, ultraviolet irradiation, ethyl methanesulphonate or 4-nitroquinoline-1-oxide mutagenesis and an enrichment method for the isolation of auxotrophs, 25 mutants with defects in the ada locus were obtained after screening 41,376 colonies. one of these, ada24, did not complement with any of the other ada mutants, had a very high reversion rate and had some other properties which usually characterize strains carrying nonsense mutations. all revertants of ada ...1979393802
the effect of ultrasound on genetic instability in diploids of aspergillus nidulans.ultrasonication at 20 khz and intensity of 59 w/cm2 of a diploid strain of aspergillus nidulans was ound to lead to a significant increase in haploidization of germinating conidiospores. in a preliminary study ultrasound was found not to have an effect on the rate of reverse mutation in conidiospore suspensions of auxotrophic mutants.1979393595
betaine-homocysteine methyltransferase in the fungus aspergillus nidulans. 1979393259
mutational studies with diquat and paraquat in vitro.diquat and paraquat were assayed in the following tests. (1) ames test in salmonella typhimurium (strains ta1535, ta1537, ta1538, ta98 and ta100) with and without rat-liver microsomal fractions. (2) resistance to 8-azaguanine in salmonella typhimurium (strain hisg46, ta92 and ta1535. (3) repair test in salmonella typhimurium (strains ta1538 and ta1978). (4) gene mutations in aspergillus nidulans: 8-ag resistance and methionine suppression (meth a1 locus). (5) lethal recessive damage in aspergill ...1979390391
recurrent mutation and selection for increased penicillin titre in aspergillus nidulans.recurrent mutation and selection has been used to increase penicillin titre in two closely related strains of aspergillus nidulans. a selection programme was initiated from each of the two strains (programmes a and b) and continued through six cycles of mutation and selection. near-ultraviolet light in conjuction with 8-methoxypsoralen was employed as the sole mutagen throughout programme a and ethyl methanesulphonate as the sole mutagen throughout programme b. excluding the first cycle of a, wh ...1979390092
deletion mapping of the niia niad gene region of aspergillus nidulans. 1979389740
genetic studies of nitrate assimilation in aspergillus nidulans. 1979389305
mms induction of different types of genetic damage in aspergillus nidulans: a comparative analysis in mutagenesis.methyl methanesulphonate (mms) was used to test the induction of gene mutation, somatic crossing-over and mitotic non-disjunction in a. nidulans. gene mutation was tested by inducing mutants resistant to 8-azaguanine and revertants of methg1 in a haploid strain. somatic crossing-over was tested in heterozygous diploids, both with a selective method, i.e. inducing homozygosis to fpa resistance in a heterozygous fpa a1/+ strain, and with a non-selective method, i.e. identifying the frequencies of ...1979388213
effect of egg-white & avidin on the growth of aspergillus nidulans & on its proteases & nadp-gdh. 1979387580
analysis of mitotic nondisjunction with aspergillus nidulans.two methods to detect the induction of nondisjunction with a diploid stable strain of a. nidulans are described. the first method gives only qualitative results, while the second method is quantitative and dose-effect curves can be done. some physiological parameters affecting the induction of nondisjunction can also be studied, because either quiescent or germinating conidia can be treated with the drug under test. some agents inducing nondisjunction were also tested for the induction of point ...1979387402
do the tightly linked structural genes for nitrate and nitrite reductases in aspergillus nidulans form an operon? evidence from an insertional translocation which separates them.previous work (rand and arst, 1977) led to the proposal that the nis-5 mutation results in a new low activity promoter for niia, the structural gene for nitrite reductase in aspergillus nidulans. expression of niia via this promoter differs from expression of niia via its normal promoter/initiator in that expression by the new promoter is not subject to nitrate induction or ammonium repression. nis-5 reduces but does not abolish niia expression mediated by the normal promoter/initiator. in this ...1979384164
product induction of purine hydroxylase ii in asperigillus the use of a mutation, hxb-20, that eliminates purine hydroxylase ii activity but retains cross-reacting material and an ancillary nadh dehydrogenase activity, it has been established that 6-hydroxynicotinic acid rather than nicotinic acid, is the true inducer of purine hydroxylase ii.1979384157
d-galactose requiring mutants in aspergillus nidulans lacking phosphoglucomutase. 1979383505
mode of action of the azasteroid antibiotic 15-aza-24 methylene-d-homocholesta-8,14-dien-3 beta-ol in ustilago maydis.ustilago maydis sporidia treated with 0.1 mug of azasterol (15-aza-24-methylene-d-homocholesta-8,14-dien-3beta-ol) per ml appeared branched and vacuolated after 6 h of incubation. sporidial multiplication, dry weight increase, and synthesis of protein, deoxyribonucleic acid, and ribonucleic acid were only slightly or moderately inhibited during the initial 3 h of incubation. an increase of free fatty acids was observed in lipid extracts of treated sporidia after incubation for 3 h or more. ergos ...1979383015
aspergillus nidulans as a test organism for assessing radio-induced chromosomal non-disjunction.a genetically marked heterozygous diploid of aspergillus nidulans was synthesized and the feasibility of using this system for the simultaneous estimation of radio-induced mitotic crossing-over and non-disjunction has been investigated. in the case of the latter, serious experimental problems have been encountered. nevertheless, induction curves for non-disjunction with 15-mev electrons, 50-kvp x-rays, beta-particles and alpha-particles are presented showing an increase in non-disjunction with i ...1979381904
[uv-induced dna degradation in aspergillus nidulans cells].uv-induced dna degradation was studied in mycellial cells of aspergillus nidulans wild type and several uvs mutants. it was shown to be an enzymatic specific process which possibly reflects the excision of pyrimidine dimers from uv-damaged dna. inhibition of dna degradation by caffeine and 2,4-dinitrophenol shows the connection between degradation and repair of dna. two ways of dna degradation were found in a. nidulans cells, one of them being glucose dependent and the other--glucose independent ...1979381100
rna polymerase from the fungus, aspergillus nidulans. large-scale purification of dna-dependent rna polymerase i (or a).the dna-dependent rna polymerase i (or a) from the lower eukaryote aspergillus nidulans has been purified on a large scale to apparent homogeneity by homogenizing the fungal hyphae in liquid nitrogen, extraction of the enzyme at high salt concentration, precipitation of rna polymerase activity with polymin p (a polyethylene imine), elution of the rna polymerase from the polymin p precipitate, ammonium sulphate precipitation, molecular sieving on bio-gel a-1.5m, binding to ion-exchangers and dna- ...1979380997
a model for hyphal growth and branching.a mathematical model for hyphal growth and branching is described which relates cytological events within hyphae to mycelial growth kinetics. essentially the model quantifies qualitative theories of hyphal growth in which it is proposed that vesicles containing wall precursors and/or enzymes required for wall synthesis are generated at a constant rate throughout a mycelium and travel to the tips of hyphae where they fuse with the plasma membrane, liberating their contents into the wall and incre ...1979379276
fine-structure mapping of the acetamidase structural gene and its controlling region in aspergillus nidulans.a large number of amds mutants altered in acetamide utilization have been used to construct a fine-structure map of the amds locus. the mutagen diepoxyoctane generated most of the deletion strains used for mapping. a minimum of 14 sites within the amds gene were found. biochemical analysis of amds mutants defined the extent of the probable coding region. a new mutant, amd-205, which did not produce detectable inactive gene product, was found to be inseparable by recombination from the "up-promot ...1979378765
genetic control of transport loss during development of aspergillus nidulans. 1979378737
identification of a gene for alpha-tubulin in aspergillus nidulans. 1979378391
characterization of a new choline locus in aspergillus nidulans and its significance for choline metabolism. 1978376401
the ability of ionizing radiations of different let to induce chromosomal deletions in aspergillus nidulans.conidia, derived from a strain of aspergillus nidulans known to carry a specific chromosomal duplication, were irradiated. the duplicated segment had genetic markers, which, when eliminated from the genome, allowed the easy detection of deletion mutants. survival curves derived following 15 mev electron and gamma-ray irradiation were characterised by the presence of an appreciable shoulder, whilst 50 kvp x-rays gave a much smaller shoulder. irradiation with beta-particles and alpha-particles gav ...1979375074
molecular cloning of the 4.2 md ecori fragment of aspergillus nidulans mitochondrial dna.the 4.2 md ecori fragment of aspergillus nidulans mitochondrial dna was cloned using the plasmid pbr 332 as vector and e. coli as host. hitherto unknown sequence of hindiii sites within this region of mitochondrial genome was established.1979375024
the regulation of hexokinase and phosphoglucomutase activity in aspergillus nidulans.the levels of glucose-6-phosphate and 6-phosphogluconate dehydrogenase in wildtype cells of aspergillus nidulans varied with the carbon and nitrogen source. in general, hexokinase activity did not vary with carbon or nitrogen source. the ammonium derepressed mutant amra1 had only 50% of the wildtype level of hexokinase. phosphoglucomutase activity was low in wildtype cells grown with nitrate, but high in cells grown with ammonium when glucose was the carbon source. a non-inducible mutant, nira-1 ...1979375022
cis-dominant regulatory mutations affecting the expression of gaba permease in aspergillus aspergillus nidulans expression of the gaba gene, the probable structural gene for the gamma-amino-n-butyrate (gaba) permease, is controlled by induction, via the inta gene, ammonium repression, mediated by the area gene, and probably carbon catabolite repression. regulatory mutations, tightly linked to gaba, were selected by reverting an arear-2 strain on gaba as nitrogen source. these mutations, gabi-1, gabi-2, and gabi-3 result in increased gaba expression and are cis-dominant in their eff ...1979375001
induced segregation in interspecific hybrids of aspergillus nidulans and aspergillus rugulosus obtained by protoplast fusion.interspecific hybrids produced by polyethylene glycol induced fusion of protoplasts from auxotrophic mutants of aspergillus nidulans and aspergillus rugulosus were grown in the presence of the recombinogens benomyl and chloral hydrate to stimulate segregation. the a. nidulans parental strains used had a known genetic marker in each linkage group. hybrids grown on complete medium containing benomyl yielded more segregants. analysis of the segregants showed that the distribution of a. nidulans lin ...1979372762
induced quantitative variation for penicillin titre in clonal populations of aspergillus nidulans.the variation in penicillin titre within populations of cultures of aspergillus nidulans derived from untreated conidia and from conidia treated with ethyl methanesulphonate (ems), near-ultraviolet light in the presence of 8-methoxypsoralen (8mop) or n-methyl-n'-nitro-n-nitrosoguanidine (ntg), each at several dose levels, was determined. both mutagentreated and untreated populations showed a continuous distribution of pencillin titres. the population mean titre of the mutagenized populations was ...1979372487
virulence genetics of aspergillus nidulans eidam: a review.studies of the influence of genotypic alterations on the murine virulence of aspergillus nidulans eidam are reviewed to emphasize the potential of this fungus for genetic studies of virulence.1978370604
[metabolic pathways of exogenous pyrimidines in aspergillus nidulans].studies on the susceptibility of the wild-type strain of aspergillus nidulans to 6-azauracil suggest that it synthesizes pyrimidines using a by-pass pathway which is induced with 6-azauracil. the effect of a series of pyrimidines on the toxic action of 5-fluorouracil, 5-fluorouidine and 5-fluorodeoxyuridine has been investigated. as the result of these studies, a scheme is proposed for the metabolism of some pyrimidine bases and nucleosides in aso. nidulans.1979370519
[use of a pyrimidine-dependent mutant for effective labeling of the dna of aspergillus nidulans].incorporation of the radioactive label from pyrimidines into rna and dna of an aspergillus nidulans pyrimidine-dependent mutant was studied. the label from [14c2]uridine was incorporated at the highest rate into both fractions of nucleic acids from a. nidulans of the wild type and pyr-mutant. the content of the label in the dna of the pyr-mutant was several times higher than that in the wild type dna. therefore, pyr-mutants can be used in order to study molecular-genetic processes in the cells o ...1978370508
regulatory properties of pyruvate carboxylase from aspergillus nidulans: evidence for the presence of a masked activator site [proceedings]. 1978369914
lactam utilisation in aspergillus nidulans: evidence for a fourth gene under the control of the integrator gene inta.mutations in the lama gene of aspergillus nidulans prevent the conversion of exogenous 2-pyrrolidone (gamma-butyrolactam) to gamma-amino-n-butyrate (gaba) and also prevent the (probably analogous) utilisation of 2-piperidone (sigma-valerolactam). the lama gene, in linkage group viii, probably specifies a lactamase but a rôle in lactam uptake cannot be ruled out. lama is probably under the control of the positive acting regulatory gene inta, which can integrate its expression with the expression ...1978368580
an "up-promotor" mutation affecting the acetamidase of aspergillus nidulans.a derivative of an area200 strain of aspergillus nidulans selected for strong growth on acetamide as the sole nitrogen source was found to have a mutation, amd-18, closely linked to amds, the acetamidase structural gene. this mutation results in 2--3 fold higher acetamidase activities than wildtype strains in uninduced as well as induced cultures. the effects of the amd-18 mutation are superimposed on the effects of other regulatory mutations affecting the acetamidase. the amd-18 mutation is cis ...1978368568
aspects of the molecular biology of lipoamide dehydrogenase. 1978367117
[presence of sexual forms (cleistothecia and hülle cells) in a case of human maxillary sinus aspergillosis caused by aspergillus nidulans in association with aspergillus fumigatus].the authors observed, in a biopsic sample from a human maxillary sinus, the coexistence, in parasitic stages, of two different aspergillus species: a. fumigatus and a. nidulans. after having described the morphologies of each species, in sections on slides, and particularly those of cleistothecia and hülle-cells for the second, they draw attention to the three interests of such an observation: -- rarety of observing aspergillus nidulans in a parasitic stage, in spite of its particular thermotole ...1978366429
isolation of dna from aspergillus nidulans.a procedure for isolation of dna from aspergillus nidulans on a preparative scale is described. mechanical disruption of lyophilized material in high-salt medium and treatment with proteinase k, followed by sedimentation of the lysate into saturated csc1 solution yielded pure, highly polymerized dna.1978364902
a hydroxamic acid from aspergillus nidulans with antibiotic activity against proteus iron-complexing antibiotic with a narrow spectrum of biological activity was produced by several strains of aspergillus nidulans when grown in a low-iron, chemically defined medium. its chemical and biological properties closely resembled those of desferritriacetylfusigen, a metabolite of several other aspergilli and penicillia.1978363670
[isolation and genetic study of aspergillus nidulans mutants defective in pyrimidine biosynthesis].8 uridine-requiring pyr mutants were isolated from aspergillus nidulans under nitrosoguanidine treatment. all the mutants are capable to grow on the medium containing 20 mkg/ml of uridine or cytidine, or 100 mkg/ml of uracil, and they do not utilize thymidine, thymine, cytosine and deoxyuridine. their ability to grow in the presence of orotic acid demonstrates that the pyrimidine synthesis in all the mutants is blocked at stages preceding the conversion of orotic acid into orotidine monophosphat ...1978363504
a mutation in the xanthine dehydrogenase (purine hydroxylase i) of aspergillus nidulans resulting in altered specificity. implications for the geometry of the active site.a point mutation in the structural gene for purine hydroxylase i (xanthine dehydrogenase) of aspergillus nidulans results in several dramatic pleiotropic effects. the mutant enzyme oxidises 2-hydroxypurine at position 6 rather than 8, shows a 70-fold reduction in the v for hypoxanthine, and loses the ability to accept xanthine as a substrate. allopurinol, a powerful pseudoirreversible inhibitor of the wild type enzyme, behaves as a good substrate of the mutant enzyme. we propose that the substra ...1978363429
the genetic control of the molybdoflavoproteins in aspergillus nidulans. iv. a comparison between purine hydroxylase i and ii.the purine hydroxylases i and ii of aspergillus nidulans [previously called xanthine dehydrogenases i and ii: scazzocchio, holl and foguelman, eur. j. biochem. 36, 428--445 (1973)] have been studied in crude extracts. the two enzymes differ in their substrate specificities, purine hydroxylase ii being able to accept nicotinate as a substrate and unable to hydroxylate xanthine. the kinetics of inhibition with allopurinol and oxypurinol are also different, the two analogues being pseudo-irreversib ...1978363427
identification of a gene for beta-tubulin in aspergillus nidulans. 1978363278
[methodological approaches to the study of ultraviolet irradiation--induced dna degradation in mycelial fungi using the example of aspergillus nidulans]. 1978363179
low repetitive dna content in aspergillus nidulans.dna-dna reassociation experiments show that the genome of aspergillus nidulans consists of approximately 97 to 98 percent unique and 2 to 3 percent reiterated sequences. the reiterated dna sequences have a complexity of about 11,000 base pairs and are repeated approximately 60 times per haploid genome. ribosomal rna-dna hybridization experiments indicate that most of the repetitive dna codes for ribosomal rna.1978362530
a quick method for testing recessive lethal damage with a diploid strain of aspergillus nidulans.a simple method capable of detecting recessive lethal damage in a diploid strain of aspergillus nidulans is described. the method scores the recessive lethals on the 1st, the 3rd and the 5th chromosomes, which represent about 40% of the total map of a. nidulans. two examples of induced lethals, with ultraviolet irradiation and methyl methanesulfonate are shown. the frequency of lethals may reach 36% of the total population with uv irradiation.1978362184
a mutation defective in the xanthine alternative pathway of aspergillus nidulans: its use to investigate the specificity of uay mediated aspergillus nidulans uric acid can be produced from xanthine via purine hydroxylase i (xanthine dehydrogenase) or via the xanthine alternative pathway (darlington and scazzocchio, biochem. biophys. acta, 166, 569--571; 1968). a mutation defective in the xanthine alternative pathway of aspergillus nidulans is described. by combining this mutation with hxb-20 which results in complete loss of purine hydroxylase i and ii activities, but which conserves cross-reacting material, it is possible to ...1978362158
reversion in variants from a duplication strain of aspergillus nidulans.strains of aspergillus nidulans with a chromosome segment in duplicate, one in normal position and one translocated to another chromosome, are unstable at mitosis. in addition to variants which result from deletions in either of the duplicate segments, which usually have improved morphology, they produce variants with deteriorated morphology. three deteriorated variants reverted frequently to parental type morphology, both spontaneously and after ultra-violet treatment. of six reversions analyse ...1978362154
pyridoxine and its relation to lipids. studies with pyridoxineless mutants of aspergillus nidulans.the effect of pyridoxine deficiency on fat metabolism was studied using mutant strains of aspergillus nidulans requiring pyridoxine for growth. under pyridoxine deficiency the mutants exhibited increased levels of total lipid, sterols, phospholipids, and triacylglycerols. total fatty acids were found to decrease with pyridoxine deficiency. an increase in saturated fatty acids and decrease in unsaturated fatty acids were seen with deficiency. pyridoxine deficiency also increased lower carbon chai ...1978361929
interaction of thiabendazole with fungal tubulin.thiabendazole, 2-(4'-thiazolyl)benzimidazole, at 80 micrometer completely inhibits mitosis in hyphae of aspergillus nidulans, growing in liquid culture. dna and rna synthesis and mycelial growth are only partially inhibited at this concentration. binding studies with cell-free mycelial extracts from penicillium expansum showed that thiabendazole competitively inhibits [14c]carbendazim binding to tubulin, which suggests that the antimitotic activity of thiabendazole is based on interference with ...1978361093
on the mechanisms of induced somatic recombination by certain fungicides in aspergillus nidulans.four fungicides interfered with the segregation of chromosomes at mitosis of aspergillus nidulans by increasing the somatic recombination, shown as colour sectors in green colonies, in a strain heterozygous for spore colour mutations. in an attempt to discover the mechanisms by which these fungicides increased the somatic recombination, a prototrophic diploid strain, heterozygous for colour and several other appropriate markers in all chromosomes, was used which enabled the detection and classif ...1978357961
distribution of autolysins in hyphae of aspergillus nidulans: evidence for a lipid-mediated attachment to hyphal walls.preparations of broken aspergillus nidulans hyphae contained both free and wall-bound autolysins. the bound enzymes were not solubilized by 8 m licl or neutral or anionic detergents; they were readily detached from walls by a cationic detergent or by autodigestion. once detached, the enzymes did not reassociate with wall to give salt-resistant complexes. six enzymes hydrolyzing wall polymers were bound to the envelope, and the same activities were also detected among soluble proteins in the cyto ...1978357422
gaba transaminase provides an alternative route of beta-alanine synthesis in aspergillus nidulans.three unlinked genes where mutation can lead to d(+)-pantothenic acid auxotrophy in aspergillus nidulans have been identified. pantoa is probably the structural gene for pantothenate synthetase (ec whilst pantob and pantoc are involved in the syntheses of d-pantoic acid and beta-alanine, respectively. a pantoc- mutant is tentatively considered to be blocked in conversion of 5,6-dihydrouracil to beta-ureidopropionate. an alternative route of beta-alanine biosynthesis occurs by the transa ...1978355840
reduced expression of a distal gene of the prn gene cluster in deletion mutants of aspergillus nidulans: genetic evidence for a dicistronic messenger in an eukaryote.the prn gene cluster involved in l-proline catabolism in aspergillus nidulans, has the gene order prna-prnd-regulatory region-prnb-prnc. prnb, prnd, and prnc specify proline permease, proline oxidase, and delta1-pyrroline-5-carboxylate (p5c) dehydrogenase, respectively. prna is probably a positive regulatory gene whose product is necessary for expression of the prn activities. proline induces proline permease and p5c dehydrogenase in prnd- mutants which lack proline oxidase, showing that proline ...1978355839
detection of mutagens produced by fungi with the salmonella typhimurium assay.forty-one fungal isolates (one isolate per species) representing common plant pathogens and food crop contaminants were grown on sterile, polished rice and assayed for mutagenic activity in the salmonella typhimurium-microsome system. initially, single doses of aqueous and chloroform extracts of the moldy rice were assayed against the ta100 tester strain by incorporating extracts into the growth medium and by applying small quantities on disks placed on the agar surface. suspected activity was e ...1978354528
multiple independent control mechanisms affecting the acetamidase of aspergillus nidulans.the acetamidase of aspergillus nidulans is induced by sources of acetyl coa, benzoate and benzamide and by beta-alanine and other omega-amino acids. the effects of these groups of inducers are appromimately additive. the cis-acting control site mutant, amdi9, affects induction by sources of acetyl-coa specifically. lesions in the amdr and gata genes affect induction by omega-amino acids specifically. mutations in the amda gene can lead to elevated acetamidase levels which still respond to the va ...1978353500
preparation of large molecular weight dna from the fungus aspergillus nidulans. 1978353226
[genetic control of the sensitivity of aspergillus nidulans to mutagenic factors. vii. inheritance of cross-sensitivity to different mutagenic factors by uvs-mutants].to study the inheritance of the sensitivity to uv, x-rays, methylmethanesulphonate (mms), nitrosoguanidine (ng) and nitrous acid (na) in five uvs mutants of aspergillus nidulans, having multiple sensitivity to these factors, the sensitivity of recombinants obtained from crossing uvs mutants with uvs+ strain, resistant to all the factors analysed, and uvs leads to uvs+ revertants is investigated. four uvs mutants (15, 17, 19 and 26) are found to have a nomogenic control of sensitivity to differen ...1977352800
the nature of an initiator constitutive mutation in aspergillus nidulans. 1978351427
sporulation competence in aspergillus nidulans: a role for iron in development.there is a difference in the response of dna from mycelial extracts of aspergillus nidulans to hot acid hydrolysis depending upon the state of sporulation competence. the dna in incompetent culture mycelia is not hydrolyzable while the dna in competent culture is hydrolyzable. the inhibition of dna hydrolysis is due to the presence of iron. although the concentration of iron decreases in mycelia during growth, there is sufficient iron present in competent mycelia to inhibit dna hydrolysis. the c ...1978350417
mutations in nira gene of aspergillus nidulans and nitrogen metabolism. 1978347305
restriction endonuclease cleavage map of mitochondrial dna from aspergillus nidulans.mitochondrial dna of the ascomycete fungus aspergillus nidulans, a circular molecule of 31 500 base pairs, is cleaved by restriction endonucleases eco r i, hind ii, hind iii and bgl ii into 3, 7, 9 and 5 fragments, respectively. the relative positions of the cleavage sites could be mapped by analysis of fragments obtained by double enzyme digestions of whole dna and by complete and partial redigestion of isolated restriction fragments.1978345242
supersuppressors in aspergillus nidulans.simultaneous reversion of mutations in two different aspergillus nidulans loci ada and metg was found to be due monogenic suppressor mutations. preliminary evidence for the existance of supersuppressors in a. nidulans is presented.1978345096
the effects of coumarin on the frequency of deletions in a duplication strain of aspergillus nidulans.strains of a. nidulans with a chromosome segment in duplicate show instability resulting from deletions in either of the duplicate segments. in dp (i, ii) strains, with the terminal segment of ir attached terminally to iir, spontaneous deletions occur most frequently, though not exclusively, from the translocated segment. coumarin, at concentrations which did not affect viability viability or growth rate, enhanced the instability of dp (i, ii) strains by selectively increasing only the deletion ...1978345093
meiotic recombination in a duplication strain of aspergillus nidulans. 1978344133
extranuclear recombination in aspergillus nidulans: closely-linked multiple chloramphenicol- and oligomycin-resistance loci.a nuclear, chloramphenicol-sensitive mutant cas-1 has been isolated which is cross sensitive to a number of drugs, including oligomycin and cycloheximide. approximately one-third of the chloramphenicol-resistant mutants isolated from mutagenized conidia of this strain were found to be extranuclear, and exhibited a variety of phenotypes. one of these mutants, designated (camb51), was slow growing on drug-free medium and recombined at low frequency with the previously described mutant (cama112) (g ...1977340908
genetic analysis of mutations of low (rec) and very high (pop) mitotic-recombination frequency in aspergillus nidulans. 1977340885
polyamine stimulation of in vivo rates of macromolecular synthesis in a putrescine auxotroph of aspergillus nidulans. 1978340271
the effect of 1,4-diaminobutanone on the stability of ornithine decarboxylase from aspergillus nidulans.1,4-diaminobutanone, a competitive inhibitor of ornithine decarboxylase in aspergillus nidulans, is able to increase the half-life of this enzyme and thus stimulate an increase in its activity in vivo. it also protects ornithine decarboxylase against proteolysis by chymotrypsin in vitro.1977339910
regulation of ammonia uptake in aspergillus nidulans.the ammonia uptake in a. nidulans was found to be linear for about 20 min, and was proportional up to 1.5 mg/ml dry cell density. the transport of ammonia does not involve energy. normal and biotin deficient a. nidulans showed an identical km-values of 10.26 x 10(-5) m ammonia for uptake. the uptake of ammonium ion has been shown to be regulated by the intracellular concentration of ammonia.1977338337
a mutation in aspergillus nidulans which affects the regulation of nitrite reductase and is tightly linked to its structural gene. 1977337118
the basis for an apparent auxotrophy for reduced sulphur metabolites in sf- mutants of aspergillus nidulans. 1977336463
the induction of mutations to 2-thioxanthine resistance in inhibitor depleted conidia of aspergillus nidulans by gamma-radiation in the presence of oxygen or nitrogen.a strain of aspergillus nidulans has been used to study the inactivating and mutagenic effect of 60cogamma-rays in the presence of oxygen or nitrogen. mutation was studied by the 2-thioxanthine system which selectively detects forward mutation at a number of gene loci (at least 16). mutants resistant to conidial pigmentation effects of 2-thioxanthine can be divided into four main classes (2txr, hx, uay and cnx) and three of these classes (hx, uay and cnx) can be further characterized at the gene ...1977335238
aspergillus nidulans mutant lacking alpha-(1,3)-glucan, melanin, and cleistothecia.a mutation in aspergillus nidulans led to a loss of both melanin and alpha-(1,3)-glucan, a major wall polysaccharide. in addition, the mutation prevented the formation of cleistothecia. mutant walls contained increased amounts of beta-(1,3)-glucan and galactose polymers, and electron micrographs indicated that they had lost the outermost wall layer. such walls were more readily digested by lytic enzymes, and this increased susceptibility to hydrolysis was due to the absence of alpha-(1,3)-glucan ...1977334748
[ultrastructural investigations on antimitotic activity of methylbenzimidazol-2-ylcarbamate (mbc) and its influence on replication of the nucleus-associated organelle ("centriolar plaque", "mtoc", "kce") in aspergillus nidulans (author's transl)]. 1977333514
the metabolism of phenylacetic acid by aspergillus fumigatus atcc 28282: identification of 2,6-dihydroxyphenylacetic acid.aspergillus fumigatus atcc 28282 converted phenylacetic acid into a new dihydroxylated compound (2,6-dihydroxyphenylacetic acid) which was identified as 2,6-dimethoxyphenylacetic acid methyl ester. two other new metabolites have been isolated also and identified as orthohydroxyphenylacetic acid and meta-hydroxyphenylacetic acid.1977332293
recent advances in basic mutation research. 1977331099
[genetic control of recombination processes in aspergillus nidulans. i. effect of uvs-mutations on the frequency of spontaneous and ultraviolet ray-induced intergenic recombination].effect of 3 uvs mutations (uvs 12, 19 and 25) on recombination processes in aspergillus nidulans is studied. all the mutations are found either to affect the fertility of carp bodies and germination ability of askospores, or result in complete inability of heterokaryons to form cleistocarpia. two mutations change the frequency of spontaneous meitotic crossing-over at pro-paba region of the chromosome i and do not affect the rate of mitotic recombination at w-centromeric region of the chromosome ...1977330315
l-asparaginase activity in the fungus aspergillus nidulans. 1977330277
regulation of glucose transport in aspergillus nidulans.pyruvate and acetate inhibited the uptake of glucose by aspergillus nidulans; although there were significant variations in glucose uptake rate, the intracellular concentration of acetate was almost identical in biotin-supplemented, normal and deficient cells. the in vitro activity of glucose-binding protein was not affected by biotin, avidin, acetate or acetyl-coa.1977330193
the genetic control of molybdoflavoproteins in aspergillus nidulans. a xanthine dehydrogenase i half-molecule in cnx- mutant strains of aspergillus nidulans.the cnx- group of mutants of aspergillus nidulans lacks xanthine dehydrogenase (xanthine: nad+ oxidoreductase, ec and nitrate reductase (ec activities and are thought to be defective in the synthesis of a molybdenum-containing cofactor, 'cnx', common to xanthine dehydrogenase and nitrate reductase [pateman, j.a., rever, b.m., cove, d.j. and roberts, d.b. (1964) nature (lond.) 201, 58-60]. the cnx cofactor has a role in maintaining the aggregated multimeric structure of nitrate ...1977330163
meiotic and mitotic recombination in aspergillus and its chromosomal aberrations. 1977327767
resistance and mitotic instability to chloroneb and 1,4-oxathiin in aspergillus nidulans.mutants resistant to two fungicides, chloroneb (1,4-dichloro-2,5-dimethoxybenzene) and vitavax (2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxathiin) were spontaneously obtained from a strain of aspergillus nidulans with frequencies of 12.5 and 1.1 respectively, in 10(8) conidia. one chloroneb-resistant mutant (chl 1) segregated as a single gene and was mapped in linkage group iv. it also caused a partial dependence of the strain on the fungicide and was semi-dominant. the mutant resistant to vitav ...1977327307
some genetical aspects of ornithine metabolism in aspergillus nidulans.a possible minor route of ornithine catabolism in aspergillus nidulans might begin with the ornithine decarboxylase reaction and end with the succinic semialdehyde dehydrogenase reaction. it is therefore of interest that the putative structural genes for these two enzymes, pua and ssua, respectively, are tightly linked group ii. however, this linkage is unlikely to have regulatory significance because ilea, the structural gene for threonine dehydratase, separates them. the gene order in this reg ...1977325361
the effects of 1,4-diaminobutanone on polyamine synthesis in aspergillus nidulans. 1977323046
effects of ethidium bromide in diploid and duplication strains of aspergillus nidulans.unstable duplication and diploid strains of aspergillus nidulans were treated with ethidium bromide, and it was shown that this drug reduces the number of sectors produced by such strains. the mechanisms which could be responsible for the partial stabilization of the strains are discussed and it is suggested that a similar mechanism is responsible for the production of sectors in both strains. it is also suggested that ethidium bromide could be useful for the reduction of instability of industri ...1977323033
two unlinked genes for the pyruvate dehydrogenase complex in aspergillus nidulans.the activity of the overall pyruvate dehydrogenase complex was found to be similar in extracts of aspergillus nidulans after growth on either sucrose or acetate. eight mutants lacking the activity of this complex were found among some 200 glycolytic mutants selected for their inability to grow on sucrose. the absence of pyruvate dehydrogenase complex activity was also confirmed for a mutant, g6 (pdha1), isolated previously. studies with the mutants supported the existence of two unlinked genes, ...1977321417
interspecific protoplast fusion and complementation in aspergilli. 1977321242
pleiotropic mutants of aspergillus nidulans altered in carbon metabolism.mutants altered in carbon catabolite regulation have been isolated by selecting for mutants of the area217 strain capable of using acetamide as the sole nitrogen source in the presence of sucrose. in addition to crea mutants described previously be arst and cove, strains with mutations in two new genes, creb and cre c, have been found. the creb and crec mutants grow poorly on some sole carbon sources and have low levels of some enzymes of carbon catabolism e.g. beta-galactosidase and d-quinate d ...1977320455
genetic damage induced by ethyl alcohol in aspergillus nidulans.heterozygous diploid conidia of aspergillus nidulans were treated during germination with ethyl alcohol in concentrations ranging from 0.25% to 20% (v/v). the diploid strain carried three recessive conidial color mutations, in addition to genetic markers on all eight pairs of linkage groups. it was thereby possible to detect events of crossing over, non-disjunction, and mutation. an increase in the dose of ethanol was associated with a decrease in conidial viability and an increase in the relati ...1977319353
enzymology and genetic regulation of a cyclic nucleotide-binding phosphodiesterase-phosphomonoesterase from aspergillus nidulans.a cyclic nucleotide-binding phosphohydrolase that possesses both a phosphomonoesterase and a phosphodiesterase catalytic function has been partially purified from aspergillus nidulans. the enzyme hydrolyzes both p-nitrophenylphosphate and bis-(p-nitrophenyl)-phosphate. o'-nucleoside monophosphates are the best physiological phosphomonesterase substrates but 5'- and 2'-nucleoside monophosphates are also hydrolyzed. the enzyme catalyzes the hydrolysis of adenosine 5'-triphosphate, adenosine 5'-dip ...1975241743
the regulation of nitrate reductase in the fungus aspergillus nidulans. 1975241670
analysis of results of catheter tip cultures in open-heart surgery patients.a statistical analysis of 628 consecutive catheter tip cultures is presented. all were from patients undergoing open-heart surgery. the previously noted effects of early removal are shown to be significant. the possible effects of stasis, flushing, handling, and place of insertion are discussed. the unresolved significance of isolations of aerobic sporing bacilli is noted, and a decreasing incidence of postoperative infective endocarditis in the same group of patients is an encouraging sign.1975235801
Displaying items 5001 - 5100 of 5149