Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| [proceedings of the 4th group of european work on the biology of physarum polycephalum: biochemical aspect and cell cycle study. innsbruck-march 19-23, 1979]. | 1979 | 497248 | |
| cadmium modification of nucleolar function and structure in physarum polycephalum. | 1979 | 505456 | |
| regulation of thymidine kinase synthesis during the cell cycle of physarum polycephalum by the heat-sensitive system which triggers mitosis and s phase. | 1979 | 510403 | |
| large scale isolation of ribosomal dna from giant surface cultures of physarum polycephalum. | 1979 | 510543 | |
| temperature-sensitive mutants of physarum polycephalum--expression of mutations in amoebae and plasmodia. | 1979 | 510920 | |
| oscillatory contraction activity in physarum. | the plasmodia of physarum polycephalum show different oscillatory phenomena (time period approximately 1.3 min) in their contraction behaviour and their protoplasmic flow. the force generating system for these phenomena is cytoplasmic actomyosin. the biochemical nature and location(s) of the oscillator(s), i.e. the clock governing these phenomena are unknown. the following locations are discussed as possible sites of the oscillator: (1) cytoplasmic actomyosin, (2) the energy supply system, (3) i ... | 1979 | 512576 |
| thymidine kinase enzyme variants in physarum polycephalum. kinetics and properties of the enzyme variants. | thymidine kinase variants of physarum polycephalum separated by repeated deae-cellulose chromatography have been characterized. the enzyme variants show similar catalytic properties (e.g., substrate specificity, ph optimum) and molecular weights, as judges by their sedimentation in sucrose gradients. however, they differ significantly with respect to pi, inhibition by dttp and thermostability, and they have slightly different km values for deoxythymidine as a substrate. | 1979 | 521445 |
| the influence of carbohydrases on the growth of fungal pathogens in vitro and in vivo. | mixtures of mycolytic enzymes from various sources release protoplasts from living fungal tissue under suitable conditions. such enzyme mixtures obtained from coprinus comatus (mycolase i), physarum polycephalum (mycolase ii) and lycoperdon pyriforme (mycolase iii) are of low toxicity in mammals when given parenterally and are able to cure experimental systemic fungal infections in mice when administered alone or in conjunction with normally ineffective levels of conventional antimycotic drugs s ... | 1979 | 523359 |
| dna synthesis in a sub-nuclear preparation isolated from physarum polycephalum. | 1979 | 526308 | |
| 1,4-alpha-glucan phosphorylase from the slime mold physarum polycephalum. purification, physico-chemical and kinetic properties. | glycogen phosphorylase from macroplasmodia of physarum polycephalum was purified 76-fold to homogeneity. the native enzyme migrated as a single protein band on analytical disc gel electrophoresis coinciding with phosphorylase activity. after reduction in the presence of sodium dodecylsulfate one protein band was detectable which corresponded to an mr of 93 000. the molecular weight of the native enzyme determined by gel sieving or gradient-polyacrylamide gel electrophoresis was 172000 and 186000 ... | 1979 | 527584 |
| isolation of a residual protein structure from nuclei of the myxomycete physarum polycephalum. | a nuclear framework structure has been obtained from isolated interphase nuclei of physarum polycephalum by extraction with 2.5 m nacl and subsequent digestion with dnase. whole-mount electron micrographs showed a nuclear lamina containing residual pore structures associated with the fibrous internal matrix. the matrix was continuous with fibrillar remnants of the nucleolus. the structure was shown to consist of 2 major polypeptides of 23,000 and 36,500 daltons as well as 30 to 40 minor polypept ... | 1979 | 528582 |
| microbubbles in replicating nuclear deoxyribonucleic acid from physarum polycephalum. | clusters of microbubbles, represent probable sites of newly initiated dna synthesis, were identified in nuclear dna from physarum polycephalum by using the electron microscope. their presence is associated specifically with s-phase. each microbubble corresponds in size to a replicating segment of dna about 100-5000 nucleotide residues in length. the dna structures containing microbubbles are metastable, and revert to native dna in the presence of moderate concentrations of formamide used to prep ... | 1979 | 534510 |
| spectral analysis of fluorescence of 8-anilino-1-naphthalenesulfonate in chemoreception with a white plasmodium of physarum polycephalum. evidence for conformational change in chemoreceptive membrane. | 1979 | 549637 | |
| identification of ng, ng-dimethylarginine in a nuclear protein from the lower eukaryote physarum polycephalum homologous to the major proteins of mammalian 40s ribonucleoprotein particles. | 1977 | 556939 | |
| laser light-scattering analysis of protoplasmic streaming in the slime mold physarum polycephalum. | laser light scattering is shown to be an effective means of obtaining a rapid, objective assessment of dynamic changes in the intact plasmodium of the myxomycete physarum polycephalum during bidirectional (shuttle) streaming. the motion of material in a 100 mum diameter region of a plasmodial vein was studied by following changes in the autocorrelation function of the fluctuations in the scattered light intensity. the autocorrelation function was recorded at 10 s intervals and analyzed to follow ... | 1977 | 556960 |
| advanced initiation of the first synchronous mitosis following coalescence of starved, uv-irradiated microplasmodia of physarum polycephalum. | 1977 | 556991 | |
| studies on mitochondrial structure and function in physarum polycephalum. v. behaviour of mitochondrial nucleoids throughout mitochondrial division cycle. | the fine structure of mitochondria and mitochondrial nucleoids in exponentially growing physarum polycephalum was studied at various periods throughout the mitochondrial division cycle by light and electron microscopy. the mitochondrial nucleoid elongates lingitudinally while the mitochondrion increases in size. when the nucleoid reaches a length of approximately 1.5 mum the mitochondrial membrane invaginates at the center of the mitochondrion and separates the mitochondrial contents. however, t ... | 1977 | 557040 |
| dna replication in physarum polycephalum: characterization of dna replication products made in vivo in the presence of cycloheximide in strains sensitive and resistant to cycloheximide. | synchronous plasmodia of cycloheximide-sensitive and cycloheximide-resistant strains of physarum polycephalum were labelled with 3[h]-deoxyadenosine in pulse and pulse-chase experiments in presence and absence of cycloheximide. the replication products were studied with alkaline sucrose gradient sedimentation analysis. we show that the action of cycloheximide on dna replication in physarum is mediated through the ribosome, since the ribosomally located resistance also makes the plasmodial dna re ... | 1977 | 557200 |
| dna replication in physarum polycephalum: characterization of replication products made in isolated nuclei. | 1977 | 557323 | |
| nucleoprotein chromatin subunit from physarum polycephalum. | the nucleoproteins resulting from digestion of the nuclei of the true slime mold pysarum polycephalum with micrococcal nuclease have been resolved according to the size classes in linear sucrose gradients containg 0.5 m nacl, and analysed for dna, rna and protein content. the basic nucleoprotein subunit has been found to contain a dna fragment of about 150--170 base pairs complexed with an approximately equal amount, on a weight basis, of basic proteins and a relatively small amount of non-histo ... | 1977 | 557341 |
| characterization of foldback sequences in physarum polycephalum nuclear dna using the electron microscope. | an examination of the foldback fraction of nuclear dna from physarum polycephalum has been carried out using the electron microscope. results show that the inverted repeat sequences responsible for the formation of foldback dna range from 150-3000 bases in length, with a number-average size of 340 bases. about one-half of the inverted sequences form looped structures with loop sizes averaging 1200 bases in length. the distance between adjacent foldback sequences is estimated to be in the range 1 ... | 1977 | 558095 |
| calcium ion fluxes across the external surface of physarum polycephalum. | 1977 | 558636 | |
| size and structure of mitochondrial dna from physarum polycephalum. | 1977 | 558892 | |
| anisomycin sensitive mutants of physarum polycephalum isolated by cyst selection. | the haploid myxamoebae of physarum polycephalum reversibly differentiate to form dormant microcysts under conditions of starvation. the thin-walled cysts can be selective recovered from a cell suspension which has been treated with the surfactant triton x-100 to lyse amoeboid forms. excystment, which is initiated by suspension in liquid medium, is inhibited by antibiotics which block protein synthesis. cysts of drug resistant mutants excyst rapidly in media containing sufficient antibiotic to ma ... | 1977 | 559241 |
| new mating types in physarum polycephalum. | 1977 | 559246 | |
| physarum polycephalum malate dehydrogenase: inhibitor analyses of the mitochondrial and supernatant isozymes. | the effects of naturally occurring metabolites were tested on the malate dehydrogenase (l-malate: nad+oxidoreductase, ec 1.1.1.37) isozymes from the eucaryotic protist physarum polycephalum. several of the krebs cycle intermediates were inhibitors for each isozyme indicating that a similar catalytic process was involved for both forms. the metabolites atp, adp, and amp were inhibitors competitive with nad for the mitochondrial isozyme but not the supernatant form. several other nucleoside phos ... | 1977 | 559534 |
| a mutation (gad) linked to mt and affecting asexual plasmodium formation in physarum polycephalum. | amoebae of the acellular slime mold physarum polycephalum convert to plasmodia both asexually and sexually. genetic analysis of a mutant that exhibits enhanced asexual plasmodium formation is reported. the mutant carries a single lesion (gad-11) located 12.3 map units from mt, a gene that controls mating specificity in sexual plasmodium formation. the mutation, which was isolated in an mt3 strain, is also expressed in mth and mt4 strains. | 1977 | 559671 |
| the organisation of genes for transfer rna and ribosomal rna in amoebae and plasmodia of physarum polycephalum. | 1. using hybridisation techniques nuclei from both amoebae and plasmodia of physarum polycephalum were found to contain 275 genes each coding for 5.8-s, 19-s and 26-s rrna, 685 genes for 5-s rrna and 1050 genes for trna. 2. hybridisation of these rna species to both amoebal and plasmodial dna fractionated on cscl gradients reveal that the 5.8-s, 19-s and 26-s rrna genes are located at a satellite position (formula: see text) with respect to the main band of dna, whereas 4-s rna genes are located ... | 1977 | 560300 |
| viability of physarum polycephalum spores and ploidy of plasmodial nuclei. | amoebae of physarum polycephalum carrying the mth mating-type allele may differentiate into plasmodia in the absence of mating. such plasmodia are haploid and, upon sporulation, produce mainly inviable spores. we have asked whether the viable spores arise from meiotic or mitotic divisions. using a microfluorometric measurement of the deoxyribonucleic acid content of individual nuclei, we found the fraction of viable spores to be correlated with the proportion of rare, diploid nuclei containing i ... | 1977 | 560366 |
| effect of sugars on salt reception in true slime mold physarum polycephalum. physicochemical interpretation of interaction between salt and sugar receptions. | interaction between salt and sugar receptions in plasmodium of physarum polycephalum was studied by using double-chamber method. effect of sugars on salt reception was evaluated by measuring membrane potential and the motive force of tactic movement of the slime mold, where salt concentration in one compartment was increased successively with a fixed sugar concentration. results are summarized as follows: (1) the presence of d-glucose, d-mannose, d-maltose, or sucrose in medium led to increase o ... | 1977 | 560489 |
| physical and kinetic distinction of two ornithine decarboxylase forms in physarum. | two forms of ornithine decarboxylase (l-ornithine carboxy-lyase, ec 4.1.1.17) can be isolated from crude plasmodial homogenates of physarum polycephalum. both forms catalyze the stoichiometric production of putrescine and co2 from ornithine, yet they are distinguished by (a) a large difference in their affinity for coenzyme (apparent km values of 0.13 and 33 mum); (b) a differential stability to extended dialysis of crude homogenates at 4 degrees c; and (c) the tendency of the low affinity form ... | 1977 | 560866 |
| [comparative study of histones from slime mold physarum polycephalum and calf thymus]. | the histones from slime mold physarum polycephalum and calf thymus were characterized in terms of some physico-chemical properties. the molecular weights of six principal histone fractions of ph. polycephalum were found to be the following: p1--22 700, p3--15 700, p4a--15 000, p4b--14 300, p5--12 800 and p6--10 500. electrophoretically homogenous histone fractions h1, h2b and h4 of calf thymus and histones p1, p3, p4b and p6 of slime mold were obtained by gel-filtration on acrylex p-60. these fi ... | 1977 | 560879 |
| [homology of histones h2b from calf thymus and p4b from slime mold physarum polycephalum]. | a comparative study of the amino acid composition of histone fractions p4b from slime mold physarum polycephalum and h2b from calf thymus was carried out using peptide mapping. it was shown that 75% of peptides are common for both proteins. the slime mold histones contain two fractions (p4b and p3), which are homologous to the h2b histone fraction of calf thymus. the data of amino acid analysis, peptide mapping and some physico-chemical properties of the histones revealed the following correlati ... | 1977 | 560880 |
| ultrastructural and radioautographic investigation of the nucleolar cycle in physarum polycephalum. characterization of dna-containing subunits. | the present study has been mainly focused on the nucleolar cycle in the slime mould physarum polycephalum. the ultrastructural characteristics of the interphase nucleolus, in this species, are quite similar to those of nucleoli in other organisms: it is essentially constituted of large particulate zones surrounding denser regions which are predominantly fibrillar in texture. the latter nucleolar zones, following fixation with osmium tetroxide, are characterized by the presence of opaque granules ... | 1977 | 561085 |
| nuclear dna content and chromosome numbers throughout the life cycle of the colonia strain of the myxomycete, physarum polycephalum. | nuclear dna content and ploidy have been determined at different stages of the life cycle of the colonia strain of the myxomycete physarum polycephalum. analyses at the plasmodial stage showed that (a) burton and fuelgen dna analyses agreed within 15% with strains which ranged from 0-6 to 3-6 pg of dna per nucleus; (b) s-phase in colonia is during the early part of interphase as in the wisconsin strain; (c) in heterothallic and heterothallic x colonia crossed strains there are 1-0-1-2 pg of dna ... | 1977 | 561091 |
| high-density induction of a quiescent cell state in physarum polycephalum. | the non-histone protein complement of physarum polycephalum changes rapidly when microplasmodia are subjected to conditions of high density. the changes in these proteins induced by high density are similar to the changes observed during starvation-induced encystment. a 50% decrease in dna synthesis, observed after 7 h of starvation, is observed after only 1 h of high density. high density also results in a decrease in rna synthesis comparable to decreases induced by prolonged starvation. total ... | 1977 | 561094 |
| oscillating contractions in protoplasmic strands of physarum: simultaneous tensiometry of longitudinal and radial rhythms, periodicity analysis and temperature dependence. | 1. the construction of a 'twin-tension transducer' allows the simultaneous measurement of the same or different contraction rhythms at any selected sites of living plasmodia of physarum polycephalum. this method has been used to analyse the relation of longitudinal and radial contraction activity within migrating plasmodia and plasmodial veins, under isometric as well as under isotonic conditions of measurement. 2. a periodicity analysis of the oscillating contraction rhythms revealed average pe ... | 1977 | 561153 |
| inverted repeat sequences in physarum polycephalum nuclear deoxyribonucleic acid [proceedings]. | 1977 | 561718 | |
| adaptation to trichodermin and anisomycin in physarum polycephalum. | 1977 | 561789 | |
| preferential binding of s-phase proteins to temporally-characteristic units of replication in physarum polycephalum. | synchronous plasmodia of physarum polycephalum were pulse-labeled with 3h-thymidine in early or late portions of the s-phase, and the binding capacity of the replicated dna for isochronous s-phase plasmodial proteins assessed by nitrocellulose filter binding assay. replication units replicating during the first one-third of the s-phase preferentially bind cytosol proteins present in plasmodia engaged in early s dna replication, while late s replicating dna exhibits a corresponding preferential b ... | 1977 | 561951 |
| physarum polycephalum histones [proceedings]. | 1977 | 562297 | |
| preparation of polysomes from synchronous macroplasmodia of physarum polycephalum. | 1977 | 562679 | |
| synthesis and transport of myosin in physarum polycephalum. | immunological techniques have been used to study the rate of synthesis and intracellular transport of myosin in the slime mould physarum polycephalum. quantitative precipitation of myosin in homogenates of physarum was achieved using an antimyosin antibody produced in rabbit in response to purified physarum myosin. dodecylsulphate-gel electrophoresis revealed that about 50% of the precipitated material is myosin. the rates of synthesis of total cellular protein and myosin were measured over the ... | 1977 | 562755 |
| the replication of ribosomal dna in physarum polycephalum. | the dna coding for ribosomal rna in physarum polycephalum exists as a collection of extra-chromosomal molecules of molecular weight 37 x 10(6). we have investigated the replication of rdna, with the following results. (a) replication of rdna is unscheduled. this means that molecules that are replicated at any particular time in one mitotic cycle have an equal probability of replicating again in each time interval in the subsequent cycle. similarly, in a single cycle, some molecules replicate mor ... | 1977 | 562757 |
| synchrony in the rhythm of the contraction-relaxation cycle in two plasmodial strands of physarum polycephalum. | rhythmicity of contraction of plasmodial strands of physarum polycephalum was studied, by measuring the isometric tension exerted by isolated segments of the strands. when 2 strands were connected by way of a plasmodial mass, the contraction-relaxation cycle of the 2 strands synchronized. such cycle activity of the strand was found to be well coordinated with shuttle streaming in the plasmodial mass which had been in connection with the strand. the presence of a control system which induces sync ... | 1977 | 562892 |
| in vitro transcription of rna in nuclei, nucleoli and chromatin from physarum polycephalum. | methods for isolating nuclei, nucleoli and chromatin from physarum polycephalum which retain high levels of endogenous rna polymerase activity are described. under carefully controlled conditions with respect to mono- and divalent cation concentrations rna synthesis in nuclei displayed linear kinetics for at least 30 min and the rna products had a similar size distribution to nuclear rna synthesis observed in vivo. chromatin showed 60% of the nuclear transcriptional activity but no conditions we ... | 1977 | 562894 |
| enzymes for rna sequence analysis. preparation and specificity of exoplasmodial ribonucleases i and ii from physarum polycephalum. | 1978 | 563399 | |
| a new method for the purification of rna polymerase ii (or b) from the lower eukaryote physarum polycephalum. the presence of subforms. | the dna-dependent rna polymerase ii or b from the lower eukaryote physarum polycephalum has been purified to apparent homogeneity by a new method employing poly(ethylene imine) precipitation and elution, and heparin-sepharose affinity chromatography. the method is readily scaled up or down and affords a purification of over 5000-fold with a yield of 35-45%. the procedure is easy to perform and can be carried out in less than three days even on a large scale. furthermore, it gives enzyme of highe ... | 1978 | 563790 |
| synthesis of protein during the nuclear division cycle in physarum polycephalum. | 1977 | 563805 | |
| structure of a beta-galactan isolated from the nuclei of physarum polycephalum. | a sulfated and phosphorylated beta-d-galactan ([alpha]d+8degrees) was isolated from the nuclei of the acellular slime mould physarum polycephalum. the polysaccharide was isolated from cesium chloride gradients during the preparation of ribosomal dna and purified. the purified galactan contained 89% galactose, 2.5% phosphate and 9.6% sulfate groups and had an average degree of polymerisation of 560. periodate degradation and permethylation studies indicated the presence of mainly (1 leads to 4)-, ... | 1978 | 564213 |
| the use of netropsin with cscl gradients for the analysis of dna and its application to restriction nuclease fragments of ribosomal dna from physarum polycephalum. | netropsin binds to dna in caesium chloride density gradients and reduces the density of the dna. the dna is saturated at a netropsin/dna weight ratio of about 6 and the change in density, deltarho, at saturation is given by deltarho = -109 (da + dt content)1.87 mg/ml for the six dnas tested covering da + dt contents from 0.28 to 0.69. at lower netropsin/dna ratios the observed density shifts are consistent with a two-site model for netropsin binding to dna. netropsin approximately doubles the re ... | 1978 | 564266 |
| control of rna transcription in nuclei and nucleoli of physarum polycephalum. | 1978 | 564291 | |
| studies on pulse-labelled rna during the mitotic cycle of physarum polycephalum by subnuclear fractionation. | a method is described for the isolation of pulse-labelled rna from nuclei and subnuclear fractions of physarum polycephalum. at all times during interphase the nucleolar rna consisted mainly of a 34-s rrna precursor with only small amounts of 26-s and 19-s rrnas. the nucleoplasmic rna consisted of predominantly mature 26-s rrna with small amounts of 19-s rrna and a 30-s rna species. the 30-s rna component displayed different labelling kinetics from the rrna precursors. a low molecular weight rna ... | 1978 | 564354 |
| the structure of nucleolar chromatin in physarum polycephalum. | the nucleolar dna of physarum polycephalum has been differentially labelled with 3h-thymidine and the structure of the nucleolar chromatin investigated by digestion with micrococcal nuclease. nucleolar chromatin which had been labelled in g2 phase of the cell cycle and then digested before mitosis had an identical dna repeat length to main band dna (165 +/- 5 base pairs) but there was a definite indication that the rate of digestion was faster for nucleolar dna than for main band dna. nucleolar ... | 1978 | 565509 |
| dna replication in physarum polycephalum: bidirectional replication of dna within replicons. | the direction of replication of dna within replicons of physarum polycephalum was studied by pulse-labelling with 5-bromouracil-deoxyriboside (brdurd) and 3h-adenosine deoxyriboside (dado), followed by ultraviolet- (uv) -photolysis and analysis of molecular weights of single strand dna fragments on alkaline sucrose gradients. newly made dna within replicons at all stages of completion is split in two equal halves upon uv irradiation when brdurd was given at the time of initiation of dna synthesi ... | 1978 | 565510 |
| cadmium modification of nucleolar ultrastructure and rna synthesis in physarum polycephalum. | 1978 | 565959 | |
| the heterogeneity of cytoplasmic deoxyribonucleic acid polymerase from physarum polycephalum. | cytoplasmic dna polymerase (dna deoxynucleotidyltransferase, ec 2.7.7.7) was partially purified from physarum polycephalum. the first step of the purification procedure utilized the fact that the enzyme on gel filtration behaves in anomalous fashion. the second step was either ion-exchange chromatography or sucrose-density-gradient centrifugation. the partially purified dna polymerase was heterogeneous and at least four species with different sedimentation coefficients (5.5s, 7.2s, 8.6s and 11.5 ... | 1978 | 566101 |
| metabolic stability of the extrachromosomal ribosomal rna genes in the slime mould physarum polycephalum. | the rrna genes of the slime mould physarum polycephalum are located on free, linear dna molecules of a discrete size, mr=38x10(6). using an isotope dilution technique we have examined the metabolic stability of these extrachromosomal genes during active, balanced growth. microplasmodia, prelabelled with [3h]thymidine, were used to prepare synchronous surface plasmodial cultures which were subsequently grown on unlabelled medium. the gross synthesis of ribosomal dna was then determined over three ... | 1978 | 566198 |
| deoxyribonucleic acid polymerase from physarum polycephalum. properties of the major cytoplasmic activity in exponentially growing microplasmodia. | dna polymerase was purified 1000-fold from the cytoplasm of microplasmodia of the myxomycete physarum polycephalum. the activity was found in two forms exhibiting molecular weights of 204000 and 116000 respectively. both forms eluted together from dna-cellulose and deae-sephadex columns. the stokes radii were 6.5 and 5.5 nm. the sedimentation coefficients were 7.6 and 5.2 s. the frictional ratios of 1.69 suggest a highly hydrated and/or an asymmetric structure of the molecule. the enzyme-catalyz ... | 1978 | 566199 |
| successful demonstration of an elusive cell coat in amebae. | cell coats were cytochemically demonstrated for the first time in myxamebae of fulig- septica, didymium iridis, dictyostelium discoideum, cavostelium apophysatum, and amebae of naegleria grubei. the stain enhances the cell coats of physarum polycephalum plasmodia, ceratiomyxa fruticulosa myxamebae, and acanthamoeba sp. cell coats usually unstained by cationic dyes stain intensely with the aid of the new cytochemical protocol utilizing 0.5% alcian blue in the primary fixative and 0.05% ruthenium ... | 1978 | 566325 |
| theoretical approach to the effects of extremely low frequency electromagnetic fields on physarum polycephalum. | 1978 | 566449 | |
| ribosomal dna in spores of physarum polycephalum. | dna was isolated from plasmodia, spores and newly hatched amoebae of the slime mould physarum polycephalum. the dna preparations were fractionated in cscl gradients and each fraction hybridised to combined 19 s + 26 s rrna. in all three dna preparations hybridisation was found to be limited to satellite dna (rho = 1.714 g/cm3) and at saturation was found to reach a level of 0.16--0.18 % of total dna. the main band of nuclear dna (rho = 1.702 g/cm3) did not hybridise appreciably. further experime ... | 1978 | 566559 |
| chromatin structure of physarum polycephalum plasmodia and amoebae. | 1978 | 566679 | |
| periodic organisation of foldback sequences in physarum polycephalum nuclear dna. | nuclear dna from the slime mould physarum polycephalum is shown to contain interspersed inverted repeat sequences, such that denatured fragments of dna containing pairs of these sequences form intra-chain duplexes under appropriate conditions. the organisation and distribution of the nucleotide sequences responsible for the formation of foldback structures in physarum dna have been investigated using the electron microscope. the majority of foldback duplexes have sizes ranging up to 800 base pai ... | 1978 | 566909 |
| [spatio-temporal analysis of contraction dependent surface movements in physarum polycephalum (author's transl)]. | plasmodial veins of physarum polycephalum were investigated by combining cinematographical and tensiometrical methods. veins remaining on their original growing substrate show characteristic surface movements resulting from an intrinsic contraction automaticity. radial and longitudinal components of surface movements were registered simultaneously. both contraction activities show identical frequencies, in contrast to results derived from experiments with isolated veins. there is only one genuin ... | 1978 | 567599 |
| cyclic production of tension force in the plasmodial strand of physarum polycephalum and its relation to microfilament morphology. | cyclic contraction and relaxation of plasmodial strands of physarum polycephalum were measured under both isotonic and isometric conditions, and their relation to changes in microfilament (mf) morphology was investigated. the contraction-relaxation rhythm of a strand segment was insignificant and irregular immediately after isolation from the mother plasmodium. it became regular half an hour later when local minute rhythms were synchronized spontaneously. if a strand kept under isotonic conditio ... | 1978 | 569161 |
| synthesis of a 125i-labelled derivative of the antibiotic griseofulvin. | a derivative of griseofulvin has been synthesised, in which the 2'-o-methyl group is replaced by a 2'-(2-iodoethoxy), 125i-labelled group. this derivative is at least as potent as griseofulvin itself, when assayed for inhibition of growth on the myxomycete physarum polycephalum. | 1977 | 591462 |
| ribosomal genes in physarum polycephalum: transcribed and non-transcribed sequences have similar base compositions. | the transcribed and non-transcribed sequences in physarum polycephalum ribosomal dna (rdna) were separated by restriction nuclease digestion of pure rdna and the products fractionated by zone sedimentation in sucrose gradients. the base compositions of the fragments were determined by analytical centrifugation in cscl or in cscl with netropsin. all the fragments had da + dt contents in the range 44-48%. from the known sequence arrangement and transcription pattern of physarum rdna it was conclud ... | 1978 | 689040 |
| effects of cytochalasin a on the morphology of plasmodia and sclerotia of physarum polycephalum. | cytochalasin a (ca) at 1.6 x 10(-5)m and lower concentrations produced disruptive effects upon plasmodia, sclerotia, and spherule forms of physarum polycephalum. ca effects upon either micro- or macroplasmodia included: cytoplasmic condensation, plasmodial contraction, and scission at the plasma membrane. the latter manifestation was most dramatically observed by scanning electron microscopy. electron microscopy of drug-treated palsmodia confirmed the above phase contrast light-microscopic resul ... | 1978 | 689245 |
| spatio-temporal relationships between protoplasmic streaming and contraction activities in plasmodial veins of physarum polycephalum. | plasmodial veins of physarum polycephalum were investigated by combining cinematographical, morphological, and tensiometrical techniques. translucent and nontranslucent (thicker) strands remaining in their original position on filter paper were analyzed in respect to their radial contraction cycles and the resulting streaming activity of the endoplasm. a new technique for measuring the flow intensity by a microbalance method allowed testing of the influence of radial contraction on actual stream ... | 1978 | 689259 |
| plasmodium of physarum polycephalum as a synchronous contractile system. | the contractile activity of veins and the rhythmicity of the frontal progress were photometrically recorded from cine-film, at numerous points across the whole plasmodium. graphic analysis of the obtained curves demonstrates the existence of common contraction rhythm over the entire network, coincident to the expansion rhythm of the advancing front. it is suggested that the plasmodium of physarum polycephalum represents an imperfectly synchronized monorhythmic contractile system. | 1978 | 689260 |
| the chemotactic response of plasmodia of the myxomycete physarum polycephalum to sugars and related compounds. | a new technique, the double strip method, for studying the chemotaxis of myxomycete plasmodia is described. physarum polycephalum was attracted by the aldohexoses d-glucose, d-galactose and d-mannose and their derivatives 2-deoxy-d-glucose and maltose, thresholds ranging from 0.25 mm (d-glucose) to 5 mm (d-mannose). these sugars competed with each other, a uniform background of one of them inhibiting taxis to the others. other attractants were n-acetyl-d-glucosamine and mannitol, with thresholds ... | 1978 | 690601 |
| growth and migration of plasmodia of the myxomycete physarum polycephalum: the effect of carbohydrates, including agar. | a method for studying the growth and migration of myxomycete plasmodia on the surface of agar and other gels was devised. the migration rate of plasmodia of physarum polycephalum was greatly reduced when nutrients that permit rapid growth were present, and slightly reduced by most sugars tested at 56 mm, including some that were not utilized. the carbohydrate requirement of the myxomycete could be satisfied by a range of sugars and derivatives, including mannitol and agar, utilization of the lat ... | 1978 | 690603 |
| actins from mammals, bird, fish and slime mold characterized by isoelectric focusing in polyacrylamide gels. | actins isolated from a variety of tissues and cultured cells were compared by isoelectric focusing in polyacrylamide gels in the presence of 9 m urea and 2% nonidet p40. actins isolated from muscle tissue with a sarcomeric structure like skeletal muscle and heart muscle invariably display, as previously shown, one single band with a pi of approximately 5.4 (alpha-actin) in isoelectric focusing gels. actins isolated from mammalian or avian non-muscle tissue and cultured mammalian cells display tw ... | 1978 | 699900 |
| aminopeptidases of physarum polycephalum during growth and differentiation. | 1978 | 708073 | |
| pyrimidine metabolism in microplasmodia of physarum polycephalum. | if microplasmodia of physarum polycephalum are exposed to 14c-labelled pyrimidine nucleosides or bases, an unusual pattern of metabolism is found. only the nucleosides are taken up. analysis of the distribution of the radioactivity in the cells revealed that ribonucleosides and deoxyribonucleosides are incorporated into nucleotides; however, a substantial catabolism takes place. thus incubation with [2-14c]pyrimidine nucleosides readily gives rise to [14c]o2, particularly in the case of [2-14c]t ... | 1978 | 710400 |
| polyamine stimulation of phosphorylation of nonhistone acidic protein in nuclei and nucleoli from physarum polycephalum. | 1978 | 710418 | |
| degradation of the ribosomal genes by dnase i in physarum polycephalum. | treatment of nuclei from physarum polycephalum with dnase i leads to dna fragments with a regular pattern of multiples of 10 nucleotides, when analyzed on gels under denaturing conditions as has been shown for other eukaryotes. reports from weintraub and axel lead to the conclusion, that active genes are preferentially digested by dnase i. when physarum chromatin is degraded by dnase i, the ribosomal genes are no longer available for hybridization with 19-s and 26-s rrna and are thus preferentia ... | 1978 | 710437 |
| chemotaxis toward carbohydrates and amino acids in physarum polycephalum. | 1978 | 710529 | |
| the influence of microinjected phalloidin on locomotion, protoplasmic streaming and cytoplasmic organization in amoeba proteus and physarum polycephalum. | microinjected phalloidin induces both time and concentration-dependent changes in morphology and motility of amoebae and acellular slime moulds. in a. proteus injection of a 10(-3)m solution of the drug causes a separation of cortical hyaline plasma from central granular plasma. simultaneously protoplasmic streaming and cellular locomotion are lost irreversibly. lowering the concentration of phalloidin to 2 x 10(-4)m results in a reversible disturbance; amoebae recover after 30 to 60 minutes and ... | 1978 | 710672 |
| poly(adenylic acid) degradation by two distinct processes in the cytoplasmic rna of physarum polycephalum. | 1978 | 718854 | |
| size distribution and maturation of newly replicated dna through the s and g2 phases of physarum polycephalum. | the size distribution of newly made dna and the dynamics of size maturation of progeny dna molecules were studied in the synchronous s and g2 phases of physarum polycephalum. pulse labeling of dna and analysis of the products on alkaline sucrose gradients showed that synthesis of primary replication units (which will also be referred to as "okazaki" fragments) occurred throughout the s period. pulse and pulse-chase experiments revealed a distinct pattern of size maturation. an apparently linear ... | 1978 | 729005 |
| effect of ionizing radiation on nucleoside metabolism in physarum polycephalum. | 1978 | 734057 | |
| control of ornithine decarboxylase activity in physarum by polyamines. | the addition of putrescine, spermidine, or spermine, to cultures of physarum polycephalum rapidly reduced the activity of ornithine decarboxylase, with maximal inhibition, 80-90%, occurring after 90 min. this response was not due to a decrease in enzyme molecules, but rather to the rapid conversion of the active enzyme to a stable, catalytically less active form. this response to exogenous polyamines was not accompanied by the appearance of a macromolecular inhibitor (antizyme) either free, or b ... | 1978 | 738271 |
| toxicity of heavy metals and insecticides on slime mold physarum polycephalum. | toxicity of heavy metals and insecticides on the slime mold physarum polycephalum was investigated in order to examine and estimate with ease the toxicity of environmental and occupational contaminants and also to study the effects of various agents on the cell membrane. changes in survival time and in membrane potential of the slime mold were measured using a double chamber method. the results obtained suggest that their toxicity for the slime mold is accompanied by some change in the cell memb ... | 1978 | 739566 |
| the structure of chromatin containing dna complementary to 19 s and 26 s ribosomal rna in active and inactive stages of physarum polycephalum. | 1978 | 742889 | |
| change of the nuclear pore frequency during the nuclear cycle of physarum polycephalum. | the change of the nuclear pore frequency during the nuclear cycle of synchronous plasmodia of physaru- polycephalum was investigated. counts were made on platinum-carbon replicas of isolated nuclei. pore numbers varied markedly at any given time of the nuclear cycle, possibly due to the variable dna contents of the nuclei. the average pore frequency per nucleus increased from 336 at 1 h after mitosis to 770 at 50 min before the subsequent mitosis. the results suggest a quantitative relation betw ... | 1978 | 748340 |
| comparison of susceptibility to staphylococcal nuclease and behaviour in metrizamide gradients of normal and 5-bromodeoxyuridine-substituted chromatin from physarum polycephalum. | replacement of 20--30% of thymine by 5-bromodeoxyuridine in chromatin dna of physarum polycephalum does not cause any visible change in a typical, regular pattern of dna products obtained upon digestion of chromatin with staphylococcal nuclease. the time course of digestion is similar for normal and substituted chromatin even under conditions when the nuclease cleaves preferentially the dat regions in dna. 5-bromodeoxyuridine label does not significantly affect the dna/protein ratio in chromatin ... | 1978 | 752203 |
| chemotaxis and movement of physarum polycephalum and its responses to some neurotransmitters and psychomimetic compounds. | a method was developed for studying the effect of some neurotransmitters and drugs on the rate of movement and the chemotactic value of the plasmodium of physarum polycephalum. epinephrine (adrenaline) at a concentration of 1 mg/ml, reduced the rate of movement and shortened the length of the cycles of shuttle streaming, but did not affect the chemotactic response. the drugs dl-amphetamine, cannabinol and heroin diminished the rate of movement, whereas na-barbitol misled the chemotactic response ... | 1977 | 753899 |
| the isolation of coupled mitochondria from physarum polycephalum and their response to ca2+. | a method for the isolation of coupled mitochondria from the acellular slime mould physarum polycephalum is described. the mitochondria oxidize respiratory substrates at rates comparable to those of mitochondria from other microorganisms and show similar responses to respiratory inhibitors. adp/o values approach similar values to those obtained with mitochondria from higher organisms: 3 with nad-linked substrates, 2 with succinate, and 1 with ascorbate-tmpd. mitochondria actively take up low conc ... | 1979 | 758941 |
| the spherule wall of physarum polycephalum: chemical analysis and electron microscopy. | 1. the composition of purified wall fragments from the spherule wall of physarum polycephalum has been studied. 2. spherule wall fragments consist of two major components. more than one-half of the wall material is glycoproteins. the remaining wall material after fractionation has a high carbohydrate to protein ratio and is suggested to be composed of proteoglycan(s). 3. the predominant monosaccharide constituent of the proteoglycan is galactosamine. the protein component is unique. it is compos ... | 1979 | 760817 |
| control of nuclear division in physarum polycephalum: comparison of cycloheximide pulse treatment, uv irradiation, and heat shock. | 1979 | 761604 | |
| [protein-bound mono (adenosine-diphosphate-ribose) levels during the cell cycle of the slime mold physarum polycephalum]. | in physarum polycephalum two fractions of adpr-protein conjugates could be differentiated on the basis of their susceptibility towards hydroxylamine. quantitation during the cell cycle revealed independent synthesis of the two species, the nh2oh-resistant fraction being formed during s phase, while the nh2oh-sensitive conjugate increased sharply at the s/g2 boundary. these findings indicated that nuclear adp-ribosylation reactions are more than one function. | 1979 | 761845 |
| temperature-sensitive mutants of the slime mould physarum polycephalum. i. mutants of the amoebal phase. | a replica plating method for isolating it amoebal mutants of physarum polycephalum has been devised. temperature-sensitive mutations occur at a frequency after nitrosoguanidine mutagenesis of 10(-3) per survivor, are stable but are not usually expressed in the plasmodia formed from these amoebae in clones. some of these mutants appear to be cell-cycle stage specific. | 1976 | 796667 |
| temperature-sensitive mutants of the slime mould physarum polycephalum. ii. mutants of the plasmodial phase. | methods are described for the isolation and testing of temperature-sensitive plasmodial strains of physarum polycephalum. nineteen temperature-sensitive strains were found by screening plasmodia derived from mutagenised amoebae and the properties of these are described. a scheme is outlined for the detection of specific mitotic cycle lesions amongst temperature-sensitive strains, and the properties of a presumptive mitotic cycle mutant are described. | 1976 | 796668 |
| ultrastructural studies of chondromyces crocatus vegetative cells. | electron microscopy of sectioned, chemically fixed chondromyces crocatus revealed a microorganism with a typical gram-negative cell envelope. the cytoplasm contained, in addition to tubules and two types of granules, a membrane-associated structure (mas) that, although less extensive, bears some resemblance to polar membranes observed in flagellated bacteria. examination of swarming cells negatively stained in situ, as well as thin sections, established that cell division occurs by septum format ... | 1975 | 811346 |
| scanning electron microscopy of fruiting body formation by myxobacteria. | scanning electron microscopy was used to follow fruiting body formation by pure cultures of chondromyces crocatus m38 and stigmatella aurantica. vegetative cells were grown on sp agar and then transferred to bonner salts agar for fructification. fruiting in both species commences with the formation of aggregation centers which resemble a fried egg in appearance. in chondromyces the elevated center or "yolk" region of the aggregation enlarges into a bulbous structure under which the stalk forms a ... | 1975 | 811649 |
| dna replication in homogenates of physarum polycephalum. | homogenates of physarum polycephalum incorporate [3h]datp into nuclear dna at an initial rate of approximately 15% of the in vivo rate. to attain this level of synthesis, cultures, are homogenized in a medium containing mg++, egta, glucose and spermine. incorporation is strongly stimulated by the addition of atp and all four deoxyribonucleoside triphosphates to homogenates prior to incubation. various inorganic cations other than mg++ either do not affect synthesis or are inhibitory. incorporati ... | 1975 | 811674 |
| [demonstration of the action of methyl benzimidazole 2 yl carbamate (mcb) and methyl(5(2 thienyl carbonyl) 1 h benzimidazole 2 yl carbamate) (r17934) on the nucleus of physarum polycephalum (myxomycetes)]. | the toxicity of these compounds was determined in the amoebae and plasmodia. an electron microscopic study shows an increase in nuclear size which is in agreement with the increase of the total amount of dna. microtubules are present but they are not organized in a normal mitotic apparatus. some other nuclear abnormalities are described. | 1976 | 825247 |
| [autoradiographic study of ribosomal rna metabolism during mitosis in the myxomycete physarum polycephalum]. | in physarum polycephalum, the study of rna metabolism just after metaphasis shows an important 3h-uridine incorporation. most of the labelling is found in the nucleolus when we can see it again during interphasis. therefore a ribosomal rna synthesis does exist before any visible nucleolar structure. | 1976 | 827386 |