| poly(adenosine diphosphate ribose) glycohydrolase in physarum polycephalum. | | 1976 | 3139 |
| defined and semi-defined media for the growth of amoebae of physarum polycephalum. | amoebae of the true slime mould physarum polycephalum were cultured in two fully-defined liquid media containing amino acids, glucose, three vitamins and a buffered salts solution. absolute requirements were demonstrated for methionine, haematin, thiamine and biotin, all of which were known to be specific requirements of the plasmodial stage. methods are described for large-scale culture in three semi-defined media. | 1976 | 8585 |
| glycosidases from the culture medium of physarum polycephalum. | eight exo-glycosidase activities were detected in the axenic culture medium of the myxomycete, physarum polycephalum. the secretion of each enzyme examined followed the growth curve and continued during the stationary phase after the cessation of growth. two or more forms of each enzyme were detected after electrophoretic separation. the beta-n-acetyl-d-hexosaminidase activity was readily separated into its two electrophoretic forms, x and y, which were purified 145- and 306-fold respectively. t ... | 1977 | 15539 |
| the relation of cycling of intracellular ph to mitosis in the acellular slime mould physarum polycephalum. | the relation between intracellular ph and the mitotic cycle of physarum polycephalum was studied by two-independent techniques. both techniques revealed a long term cycling of intracellular ph which has the same period as the mitotic cycle, qualitative detection of the changes in intracellular ph was made by measuring the changes in fluorescence of 4-methylesculetin which had been absorbed by the plasmodium. quantitative measurements of intracellular ph were made throughout the mitotic cycle wit ... | 1977 | 16937 |
| endonuclease activity in nuclei of physarum polycephalum. partial purification and characterization. | an endonuclease, present in the microplasmodia of physarum polycephalum, has been partially purified from isolated nuclei by deae-cellulose and sephadex g-75 chromatography. 1. the endonuclease produced single-strand scissions in double-stranded dna which resulted in the generation of 5'-phosphoryl and 3'-hydroxyl termini. no activity was observed with single-stranded dna as substrate. 2. the ph optimum was approximately 8.5. 3. divalent cations were essential for enzyme activity. mncl2 and mgcl ... | 1977 | 20146 |
| intracellular and extracellular beta-n-acetylhexosaminidases from physarum polycephalum. comparison of vegetative and spherulation enzymes. | | 1977 | 21622 |
| measurement of chemotaxis in the slime mold physarum polycephalum. | | 1978 | 30643 |
| the activity of guanylate cyclase and cyclic gmp phosphodiesterase during synchronous growth of the acellular slime mould physarum polycephalum. | | 1979 | 34395 |
| purification of an alkaline nuclease from physarum polycephalum. | an alkaline nuclease was purified from microplasmodia of physarum polycephalum. the nuclease, active on denatured dna and rna and free of contamination by other nucleolytic activities, appeared to be a zinc-metallo protein. the enzyme was only active under conditions, where zn2+ were retained in the enzyme. loss of zinc occurred by the chelating action of edta, egta or ampholines, by acid of highly alkaline ph conditions or by high ionic strength. the addition of zncl2 to compensate losses, rest ... | 1979 | 41584 |
| the role of regulation of cell speed in the behavior of physarum polycephalum amoebae. | | 1979 | 41731 |
| activity, isoenzyme pattern, and synthesis of udpglucose 4-epimerase during differtiation of physarium polycephalum. | 1. the specific activity of udpglucose 4-epimerase (ec 5.1.3.2) increases by about 50% during the first 24 h of starvation-induced differentiation (spherulation) of physarum polycephalum. 2. at all stages during differentiation, the enzyme activity is very sensitive to actinomycin-c and cycloheximide, inhibitors of transcription and translation, with a half life against cycloheximide of about 20 min (if added 12 h after the induction of differentiation). 3. the isoenzyme pattern, as revealed by ... | 1975 | 47762 |
| demonstration of cytoplasmic actomyosin fibrils by the freeze-etching technique. | cytoplasmic actomyosin fibrils of physarum polycephalum were demonstrated by the freeze-etching technique. within the fibrils the electron micrographs reveal 40-80 a thick filaments presumably representing f-actin. thicker filaments (myosin) could not be detected. to avoid freezing artefacts, a pretreatment of the living material with 50% sucrose was necessary. the influence of freeze-protecting agents upon the fine structure of cytoplasmic actomyosins and the resulting difficulties in the inves ... | 1975 | 51462 |
| [acid phosphomonoesterase of physarum polycephalum]. | | 1976 | 71055 |
| studies on the activities of an acid phosphomonoesterase and an alkaline pyrophosphatase during the growth of physarum polycephalum. | after an initial decrease, the specific activity of physarum polycephalum acid phosphomonoesterase increases during the growth of the organism in an axenic medium. this increase is independent of the inorganic phosphate concentration in the culture medium. the specific activity of inorganic alkaline pyrophosphatase remains constant during the growth and is not modified by a high extracellular concentration of orthophosphate. during starvation in a non nutritive saline medium, the increase of aci ... | 1977 | 71089 |
| [isolation, purification and characterization of the beta-galactosidase of physarum polycephalum (proceedings)]. | | 1977 | 71119 |
| purification and quaternary structure determination of an acid phosphatase and beta-galactosidase from the myxomycete physarum polycephalum [proceedings]. | | 1977 | 79385 |
| [regulation of some hydrolases in the myxomycete physarum polycephalum (proceedings)]. | | 1978 | 81005 |
| [yellow pigments of the myxomycete physarum polycephalum (proceedings)]. | | 1978 | 81006 |
| patterns of nucleic acid synthesis in physarum polycephalum. | | 1979 | 95053 |
| [ultrastructural study of the nucleolar cycle in physarum polycephalum using edta preferential stain for rnp (author's transl)]. | | 1979 | 104873 |
| selective modification of positive chemotaxis in the true slime mold physarum polycephalum by ethylenediaminetetraacetic acid treatment. | the plasmodium of the true slime mold physarum polycephalum was treated with edta or egta and the effect of the treatment on the chemotactic response was examined by measuring the chemotactic motive force with the double-chamber method. the results obtained were as follows: (1) the treatment of the plasmodium with 5 mm edta (ph 7.0, 20 min) did not give any significant effect on the protoplasmic streaming or motility. (2) the plasmodium treated with edta exhibited no chemotactic response to non- ... | 1979 | 114232 |
| identification of sarcoplasmic reticulum-like system in physarum polycephalum. | | 1979 | 116871 |
| calcium sensitivity of hybrid complexes of muscle myosin and physarum proteins. | 1. a myosin-actin hybrid complex was used to study actin-associated calcium sensitivity of a "cytoplasmic" actomyosin. the approach should be generally applicable. 2. low salt extracts of physarum polycephalum contain actin which remains in solution after centrifugation at 46 000 times g or at 100 000 times g for 1 h. the actin was precipitated by the addition of muscle myosin to the supernatants and detected in the hybrid complex by electron microscopy, sodium dodecyl sulfate gel analysis, supe ... | 1975 | 126082 |
| ca2+-sensitivity of actomyosin atpase purified from physarum polycephalum. | a contractile protein closely resembling natural actomyosin (myosin b) of rabbit skeletal muscle was extracted from plasmodia of the slime mold, physarum polycephalum, by protecting the sh-groups with beta-mercaptoethanol or dithiothreitol. superprecipitation of the protein induced by mg2+-atp at low ionic strength was observed only in the presence of very low concentrations of free ca2+ ions, and the mg2+-atpase [ec 3.6.1.3] reaction was activated 2- to 6-fold by 1 mum of free ca2+ ions. crude ... | 1975 | 131790 |
| a calcium-sensitive preparation from physarum polycephalum. | differential ultracentrifugation of an extract of the plasmodium of physarum polycephalum yields a high-speed fraction which exhibits calcium-sensitive adenosine triphosphate activity at low ionic strength. the rate of inorganic phosphate production increased from 2- to 25-fold in different preparations when the calcium concentration was increased from about 10(-8) to 10(-5) m. complement fixation using specific antibody to physarum myosin showed the fraction to contain 3% myosin. by electron mi ... | 1976 | 134744 |
| the control of mitosis in physarum polycephalum: the effect of delaying mitosis and evidence for the operation of the control mechanism in the absence of growth. | possible mechanisms coordinating the control of mitosis and dna synthesis with growth were experimentally tested in physarum polycephalum by the response of plasmodia to 2 different kinds of perturbation of the dna:mass ratio. mitosis and dna synthesis were delayed without stopping growth either by the use of fluorodeoxyuridine (fudr) or puromycin, in both cases the delayed mitosis was followed by a single shortened intermitotic period, as predicted by all the mechanisms considered and substanti ... | 1976 | 135767 |
| observations on the kinetics, subunit composition, and sulfhydryl reactivity of myosin from physarum polycephalum. | a highly purified preparation of myosin from physarum polycephalum has been shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis to contain heavy chains and only one molecular weight class of light chains, of approx. 15 000 daltons. kinetic investigations of the ca2+-atpase and mg2+-atpase (atp phosphohydrolases, ec 3.6.1.3) at ph 8.0 gave km and v values of 17.3 mum and 1.25 mumol pi/min per mg, and 2.4 mum and 0.12 mumol pi/min per mg, respectively. adenylyl imidodiphosphate, a b ... | 1977 | 137751 |
| uptake of calcium ions into microsomes isolated from physarum polycephalum. | membranous vesicles (microsomes) were isolated from plasmodia of the acellular slime mold, physarum polycephalum. the microsomes were about 0.2 about 0.2 micronm in diameter, and about 10 nm thick. the main protein component of the vesicles had a molecular weight of 100,000 daltons. calcium ions were taken up by the microsomes only in the presence of mg2+- atp. the maximum amount of ca2+ ions accumulated in the microsomes was 0.24 micronmole/mg protein. the ca2+ uptake was not accelerated by oxa ... | 1977 | 139403 |
| spherule wall formation by physarum polycephalum. | | 1977 | 143675 |
| physarum action. observations on its presence, stability, and assembly in plasmodial extracts and development of an improved purification procedure. | actin is readily extracted from plasmodia of physarum polycephalum by low ionic strength solutions which do not solubilize the plasmodial myosin. the actin in such extracts exists predominantly as a monomer which slowly denatures, apparently via removal of bound nucleotide, and is subsequently proteolyzed. however, the native monomeric actin can be induced to assemble into polymeric arrays under appropriate solvent conditions. actin assembly is dependent on the addition of atp and is a function ... | 1977 | 143958 |
| replacement of endoplasm with artificial media in plasmodial strands of physarum polycephalum. effects on contractility and morphology. | | 1978 | 151630 |
| characterization of an endogenous transcription inhibitor from physarum polycephalum. | a substance has been purified from isolated nuclei of physarum polycephalum by equilibrium and velocity gradient centrifugations, ion exchange chromatography and gel filtration which has a high molecular weight, can be labeled in vivo with 32p, is heat stable and resistant to amylases, proteases, nucleases and phosphodiesterase but is sensitive to phosphatases or hydrolysis. this material consists of phosphate and glycerol. it selectively inhibits in vitro transcription of rna polymerases, predo ... | 1979 | 155953 |
| some properties of physarum actinin. a regulatory protein of actin polymerization. | a factor termed physarum actinin was isolated and partially purified from plasmodia of a myxomycete, physarum polycephalum. when physarum actinin was mixed with purified physarum or rabbit striated muscle g-actin in a weight ratio of about 1 actinin to 9 actin and then the polymerization of g-actin induced, g-actin polymerized to the ordinary f-actin on addition of 0.1 m kcl. however, it polymerized to mg-polymer on addition of 2 mm mgcl2. the reduced viscosity (etasp/c) of the mg-polymer was 1. ... | 1979 | 157167 |
| the development of sporulation competence in physarum polycephalum. | | 1979 | 159846 |
| threshold phenomena in chemoreception and taxis in slime mold physarum polycephalum. | the plasmodium of physarum polycephalum reacts to various kinds of chemicals substances and moves towards or away from them. threshold concentration of recognition of chemicals was examined in terms of membrane potential and of the averaged motive force of tactic movement by using a double-chamber method, i.e., a single plasmodium was placed between two compartments through a narrow ditch, and differences in membrane potential and in pressure between two compartments were measured. results are s ... | 1975 | 163890 |
| change in zeta potential and membrane potential of slime mold physarum polycephalum in response to chemical stimuli. | electrophoretic study of microplasmodia of the true slime mold physarum polycephalum was carried out in the presence of various concentrations of inorganic salts, nucleotides and sugars, and the zeta potential at the surface of the plasmodia was determined from the electrophoretic mobilities. the membrane potential of the plasmodia was also measured under the same external conditions. it was shown that changes in the membrane potential induced by the chemical stimuli agreed approximately with th ... | 1976 | 174751 |
| change in atp-pyrophosphohydrolase activity during spherule formation of physarum polycephalum. | the activity of ca2+-dependent atp pyrophosphohydrolase was found to fluctuate during spherule formation of the acellular slime mold physarum polycephalum under starving incubation. the enzyme activity increased up to 16-fold at the 3rd day of the starvation, then decreased drastically to less than its original level. column chromatography of the enzyme preparation suggested that the increase in the activity was due to de novo synthesis of a new isozyme. cycloheximide inhibited the synthesis. th ... | 1976 | 175839 |
| cell-cycle dependence of two nuclear histone kinase enzyme activities. | growth-associated histone kinases have been extracted from physarum polycephalum nuclei and resolved into two components by ion-exchange chromatography. the two component activities have different substrate specificities and different times of appearance in the cell cycle. it is proposed that the enzyme(s) phosphorylate h1 histone in vivo in g2 phase, possibly sequentially in time at different sites in the h1 amino acid sequence. | 1976 | 182490 |
| fluctuations in cyclic adenosine 3':5'-monophosphate and cyclic guanosine 3':5'-monophosphate during the mitotic cycle of the acellular slime mould physarum polycephalum. | | 1976 | 183780 |
| timing of mitosis in physarum polycephalum: effects of agents affecting cyclic amp concentrations. | cultures of physarum polycephalum incubated with caffeine or theophylline for over 100 min prior to mitosis exhibited mitotic delay proportional to the time of treatment before 100 min. starved cultures exhibited mitotic delay at times of starvation longer than 180 min and slight stimulation from 100-180 min. dibutyryl camp appeared to accelerate reconstruction of the nucleus following mitosis. | 1977 | 188679 |
| cross-reacting nuclear non-histone antigens from physarum polycephalum and ehrilich ascites cells [proceedings]. | | 1977 | 199503 |
| an adenosine-3',5'-monophosphate activated adenylate cyclase in the slime mold physarum polycephalum. | | 1978 | 208869 |
| activation of histone kinase in g2 phase of the cell cycle in physarum polycephalum. | | 1978 | 212304 |
| chemotaxis: not a prerequisite for plasmodia coalescence in physarum polycephalum. | | 1978 | 215149 |
| adenylate cyclase and cyclic amp phosphodiesterase activity during the mitotic cycle of physarum polycephalum. | | 1978 | 216353 |
| ca2+-binding modulator protein in protozoa and myxomycete. | ca2+-binding protein with the properties of brain modulator protein of 3,5-cyclic nucleotide phosphodiesterase was identified in physarum polycephalum plasmodia and in euglena gracilis and amoeba proteus cells by urea polyacrylamide gel electrophoresis and activation of cyclic nucleotide phosphodiesterase and of myosin light chain kinase. | 1979 | 222487 |
| purine metabolism in microplasmodia of physarum polycephalum. | the uptake and utilization of purine nucleosides and purines in microplasmodia of physarum polycephalum were investigated. the results revealed a unique pattern, namely that exogenous purine nucleosides are readily taken up and metabolised, while free purine bases are hardly taken up. the pathways of incorporation have been elucidated in studies with whole cells and with cell-free extracts. the ribonucleosides (adenosine, inosine and guanosine) can be converted into ribonucleotides in two ways; ... | 1979 | 223640 |
| cyclic 3',5'-amp phosphodiesterase in physarum polycephalum. i. chemotaxis toward inhibitors and cyclic nucleotides. | the effect of several inhibitors of the enzyme cyclic 3',5'-amp phosphodiesterase as chemoattractants in physarum polycephalum was examined. of the compounds tested, 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (roche 20-1724/001) and 1-ethyl-4-(isopropylidinehydrazino)-1h-pyrazolo-(3,4-b)-pyridine-5-carboxylic acid ethyl ester, hydrochloride (squibb 20009) were the most potent attractants. 3-isobutyl-1-methyl xanthine, theophylline, and morin (a flavanoid) were moderate attractants and someti ... | 1979 | 228761 |
| cyclic 3',5'amp phosphodiesterase in physarum polycephalum. ii. kinetic properties. | some kinetic characteristics of soluble and particulate cyclic 3',5'-amp phosphodiesterases from physarum polycephalum are presented. the nature of enzyme inhibition by various agents is reported. the relationship between various enzyme inhibitors and their reported chemotactic properties in physarum is examined. the results suggest that the chemoattractant effect of several inhibitors may be related to their ability to inhibit the particulate and extracellular phosphodiesterases, but is unrelat ... | 1979 | 228762 |
| thymidine kinase enzyme variants in physarum polycephalum. in vitro interconversion of the enzyme variants. | isoelectric focusing of plasmodial extracts of physarum polycephalum demonstrated the presence of several multiple enzyme variants of thymidine kinase, which appear sequentially during the nuclear division cycle. variants (a) + (a1) are the only enzyme variants found in the late g2-phase, whereas the variants (c) + (c1) are only present at the time of mitosis and s-phase (1, 2). evidence is presented that multiple forms of thymidine kinase (a) + (a1) with high pi arise by dephosphorylation of a ... | 1979 | 230187 |
| two forms of beta-n-acetylhexosaminidase from physarum polycephalum. | | 1975 | 236942 |
| proceedings: enzymes degrading poly(adp-ribose) from physarum polycephalum and nicotiana tabacum. | | 1975 | 237001 |
| a calcium ion-dependent atp pyrophosphohydrolase in physarum polycephalum. | an activity of atp pyrophosphohydrolase (ec 3.6.1.8) was found in the soluble fraction of the plasmodium of physarum polycephalum. the products of the enzyme reaction were inorganic pyrophosphate and 5'-amp in equimolar quantities. the enzyme had a pronounced requirement for ca2+ with high specificity. mg-2+ was not an essential cofactor but stimulated the enzyme activity about 2.5-fold of the control. the enzyme hydrolyzed itp, gtp and beta,gamma-methylene atp at a limited rate. among inhibitor ... | 1975 | 238634 |
| poly(adenosine diphosphate ribose) polymerase in physarum polycephalum. | 1. the isolated nuclei of the slime mould physarum polycephalum contain an enzyme that will incorporated [adenine-3h] nad+ into an acid-insoluble product, which is shown to be poly(adp-ribose). 2. this incorporation has an optimum ph of 8.2 and a temperature optimum below 10degreesc. 3. optimum stimulation is given by 15 mm-mg2+. 4. 2-mercaptoethanol or dithiothreitol also stimulates the incorporation, the latter at an optimum concentration of about 1 mm. 5. under optimum conditions the km value ... | 1975 | 239697 |
| an extracellular inducer of asexual plasmodium formation in physarum polycephalum. | asexual conversion of amoebae to plasmodia was studied in the colonia isolate of the myxomycete, physarum polycephalum. when a culture of colonia amoebae is grown on a bacterial lawn, a period of amoebic growth precedes the appearance of cells committed to the plasmodial state. the onset of plasmodium production appears to be related to amoebic nutrition since cultures supplied with fewer bacteria display earlier differentiation. for a period of time after differentiation is initiated, conversio ... | 1977 | 265558 |
| altered nucleosome structure containing dna sequences complementary to 19s and 26s ribosomal rna in physarum polycephalum. | the localization of dna sequences coding for ribosomal rna was studied by hybridization of purified ribosomal rna to dna from chromatin fragments prepared by limited digestion of physarum nuclei with staphylococcal nuclease. the 32p-labeled 19s and 26s rna hybridized to dna from nucleosome monomers, dimers, trimers, and higher oligomers, separated by sucrose gradient centrifugation, although the level of hybridization to dna from nucleosome fractions was less than the level of hybridization to u ... | 1978 | 274703 |
| polyamine-mediated phosphorylation of a nucleolar protein from physarum polycephalum that stimulates rrna synthesis. | an acidic nucleolar phosphoprotein with a subunit m(r) of 70,000 was purified as an apparent dimer of 139,000 from isolated nuclei of the slime mold physarum polycephalum. the protein was purified without the aid of strong dissociating agents after its selective phosphorylation in isolated nuclei by a polyamine-mediated reaction. its amino acid composition resembled that of a nucleolar phosphoprotein from novikoff hepatoma ascites cells. the phosphoprotein stimulated rrna synthesis 5-fold by rna ... | 1979 | 288043 |
| cycloheximide-induced mitotic delay in physarum polycephalum. | cycloheximide pulses applied to physarum polycephalum surface plasmodia delay mitosis. pulses applied in g2 cause a delay of mitosis which is linearly dependent on the phase in the cell cycle at which the pulse is applied. a 30 min pulse of 10 micrograms/ml cycloheximide starting in g2 at time t after mitosis induces an excess delay (delay in excess of pulse duration) of the next mitosis of (0.55) t-1.3 h. the excess delays induced by 7 h pulses during g2 are at most 1 h larger. pulses applied l ... | 1978 | 299645 |
| dna replication in physarum polycephalum: uv photolysis of maturing 5-bromo-deoxyuridine substituted dna. | combinations of 5-bromodeoxyuridine (brdurd) and 3h-deoxyadenosine (3h-dado) short pulses were given in the synchronous dna-replication period of physarum polycephalum. after a chase period, uv-photolysis products were analyzed on alkaline sucrose gradients. this strategy has allowed the following conclusions. a) at the time of master-initiation of dna replication, points separated by 1.1-2.2x10(7) daltons of single strand dna may initiate dna synthesis. b) among these, only selected groups of r ... | 1978 | 309109 |
| translational regulation of polysome formation during dormancy of physarum polycephalum. | the translational activity of actively growing microplasmodia and dormant microsclerotia of physarum polycephalum was investigated by analyzing the distribution of ribosomes in polysomes. microplasmodial post-mitochondrial fractions contained substantial amounts of polysomes and ribosomal subunits but very few native monosomes. during the starvation period which preceded microsclerotium formation, polysome levels remained constant, whereas the subunit titer began to increase. during encystment r ... | 1979 | 315405 |
| activity of some dehydrogenase enzymes in mitochondria from physarum polycephalum. | 1. coupled mitochondria were isolated from exponentially growing physarum polycephalum. 2. activity of malate dehydrogenase (oxalacetate reduction) was 10.9 mumol/min/mg protein; the apparent km was 64 microm. 3. the activity of nadp-isocitric dehydrogenase (idh) was 110 nmol/min/mg with apparent km of 35 microm. 4. nad-idh showed allosteric properties with amp as a positive modulator. the apparent km for the unmodulated activity, 2 mm, was decreased to 0.95 mm by 0.13 mm amp. 5. succinic dehydr ... | 1979 | 318427 |
| ca++ regulation in caffeine-derived microplasmodia of physarum polycephalum. | caffeine-derived microplasmodia possess a ca++-sequestering system which can initiate motility. the experiments presented here suggest that this system is membranous and nonmitochondrial in nature. therefore, it is proposed that the shuttle streaming in the plasmodium is controlled by the localized release and uptake of free ca++ from an intracellular storage system analogous to the sarcoplasmic reticulum. | 1977 | 319101 |
| a nuclear elongation factor of transcription from physarum polycephalum in vitro. | homogenates of physarum plasmodia contain a factor which stimulates ump incorporation on native dna by solubilized homologous rna polymerases in vitro. the factor is a heat-sensitive protein and has been located in nuclei. it does not alter the template activity of dna nor the initiation frequency of transcription. the factor interacts with free or bound rna polymerase molecules (only 37 degrees c and at low ionic strength) and yields larger transcripts in vitro. the level of the factor in vitro ... | 1977 | 323008 |
| synthesis of transfer rna during the synchronous nuclear division cycle in physarum polycephalum. | 1. the synthesis of trna during the synchronous nuclear division cycle in plasmodia of physarum polycephalum has been investigated using an isotope dilution procedure and compared to the pattern of synthesis of rrna. 2. the synthesis of both trna stops during mitosis. as the genes for the two types of rna are not linked, this finding suggests that cessation of synthesis during nuclear division is a common characteristic of all types of transcription, supporting earlier work using pulse labelling ... | 1977 | 336369 |
| molecular cytochemistry: incorporation of fluorescently labeled actin into living cells. | actin labeled with 5-iodoacetamidofluorescein has been incorporated into the functional pool of actin in chaos carolinensis and physarum polycephalum by direct microinjection. the functional activity of the labeled actin has been analyzed at three levels of organization as: (a) with the purified actin, (b) in motile extracts of cells, and (c) in living motile cells. the labeled actin exhibited normal polymerization and activated myosin atpase to a similar extent as unlabeled controls. labeled ac ... | 1978 | 345279 |
| ultrastructural localization of beta-d-galactan in the nuclei of the myxomycete physarum polycephalum. | the acellular slime mold physarum polycephalum produces an extracellular sulfated and phosphorylated beta-d-galactan which was recently isolated from the nuclei of this organism. this polysaccharide has now been localized in the nuclei of p. polycephalum by electron microscopy using a specific "sandwich" technique: thin sections of p. polycephalum microplasmodia were incubated with the ricinus communis lectin specific for d-galactose residues. the bound lectin was then localized with gold granul ... | 1978 | 356891 |
| degradation of bacterial lipopolysaccharide by the slime mould physarum polycephalum. | a strain of the acellular slime mould physarum polycephalum degraded lipopolysaccharides (lps) from a variety of bacteria. the anticomplementary (ac) activity of lps was greatly reduced, as was the content of lauric, myristic, and palmitic acids, and the ability to sensitize erythrocytes to agglutination by antibody. these results indicate that physarum has enzymes which reduce the lipid a moiety of lps. in contrast, 2-keto-3-deoxy-d-manno-actanoic acid (kdo), immunodominant sugars, and beta-hyd ... | 1979 | 373869 |
| properties of antinuclear antibodies that cross-react with plasma membranes. | certain human antinuclear antibodies (ana) cross-react specifically with the surface membrane of human leucocytes. in the present work these cross-reacting (x) ana could be eluted directly from viable leucocytes isolated from three patients. the plasma membrane antigen recognized by x-ana appeared phylogenetically highly conserved since it was present on viable hela cells and cells from mouse and rabbit spleen, rat liver, and the slime mould physarum polycephalum. x-ana did not react with the pl ... | 1979 | 375379 |
| a comparative survey of the function, mechanism and control of cellular oscillators. | this review attempts to survey in a uniform manner the available evidence concerning the generation and behaviour of several well-investigated cellular oscillators. members of two broad classifications are contrasted: (i) cytoplasmic oscillations, where the periodic phenomena is generated by an instability pathway and (ii) membrane oscillators in which a membrane potential rhythm is generated at the membrane. interactions between the cytoplasmic and membrane compartments are considered and the e ... | 1979 | 390080 |
| partial purification and characterization of a protein lysine methyltransferase from plasmodia of physarum polycephalum. | plasmodia of physarum polycephalum have an active protein lysine methyltransferase (s-adenosylmethionine:protein-lysine methyltransferase, ec 2.1.1.43). this enzyme has been purified 40-fold with a 13% yield, and it catalyzes the transfer of methyl groups from s-adenosyl-l-methionine to the epsilon-amino group of lysine residues with formation of n epsilon-mono-, n epsilon-di-, and n epsilon-trimethyllysines in a molar ratio of 4:1:1 based on [14c]methyl incorporation into the methylated lysines ... | 1979 | 391266 |
| an immunological approach to the isolation of factors with mitotic activity from the plasmodial stage of the myxomycete physarum polycephalum. | nuclear divisions in plasmodia of physarum polycephalum were advanced by applying immunologically purified plasmodial extracts of late g2 phase on the surface of plasmodia which were 1.5 h before the third mitosis. the purification of g2 extracts was achieved by interaction of antibodies prepared against the antigens of early s phase plasmodia with the antigens of late g2 plasmodia. there was no advancement of mitosis by extracts prepared from early s phase plasmodia. untreated g2 extracts did n ... | 1978 | 400913 |
| melanin biosynthesis during differentiation of physarum polycephalum. | melanin synthesis in the myxomycete physarum polycephalum occurs during sporulation but not during spherule formation. melanin-like pigment was extracted from spores. an almost identical substance of polyphenols was extracted from spherules and characterized by its ultraviolet and infrared absorbance spectra. polyphenol oxidase activity in spherules was very low and showed only one weak isoenzyme band in isoelectric focusing polyacrylamide gels. a much higher activity, and an increasing number o ... | 1977 | 407942 |
| localization of lytic activities in the plasmode of physarum polycephalum: beta-galactosidase and acid phosphatase [proceedings]. | | 1977 | 410682 |
| [nucleolar structure during the prophase of physarum polycephalum]. | with sugihara's fixation technique, electron microscopic study of early-prophase nucleolus in the physarm polycephalum showed the existence of particular fibrillar structures. the characteristic feature of these spherical structures is an electron-lucid center surrounded by a dense fibrillar component. their relationships between the "fibrillar centers" and between the rate of ribosomal rna synthesis are studied. | 1977 | 413663 |
| isolation of a minichromosome containing the ribosomal genes from physarum polycephalum. | the ribosomal genes of physarum polycephalum are located on linear dna molecules (rdna) of 38 x 10(6) daltons present in each nucleolus in 100--200 copies. the rdna is not part of the large chromosomal dna. these molecules have now been solubilized in the form of transcriptionally active deoxyribonucleoprotein complexes from nucleoli purified through percoll gradients. the ribosomal chromatin (rdnp) sediments in sucrose gradients as a homogeneous fraction with an approximate sedimentation coeff ... | 1979 | 420794 |
| post-fusion somatic incompatibility in plasmodia of physarum polycephalum. | high-resolution autoradiography has been used to establish that during the incompatibility reaction that follows fusion between plasmodia of a 'killer' and a 'sensitive' strain of the myxomycete physarum polycephalum, the nuclei of the sensitive strain are selectively damaged, enclosed in vacuoles and eliminated from the cytoplasm. this damage is visible as increased chromatin condensation and nucleolar segregation. nuclear envelopes of both strains show blebbing, and there is an increase in the ... | 1979 | 422675 |
| ribosomal phosphoproteins in physarum polycephalum. | | 1979 | 426826 |
| accessibility of the ribosomal genes to micrococcal nuclease in physarum polycephalum. | in physarum polycephalum most genes coding for ribosomal rna are not integrated in chromosomes, but are located in many copies in the nucleolus as plasmid-like palindromic dna molecules. to find out whether coding sequences of rdna are organized in a chromatin-like structure similar to that of bulk chromatin, nuclei were treated with micrococcal nuclease and dna fragments were isolated. from bulk chromatin multimers of a basic unit of 170-180 base pairs were obtained. nuclease fragmented dna hyb ... | 1979 | 427166 |
| presence of the epsilon-(gamma-glutamic)lysine crosslink in cellular proteins. | the epsilon-(gamma-glutamic)lysine bond is a covalent interaction which has been found to crosslink polypeptide chains of a number of extracellular proteins. among known covalent bonds crosslinking protein chains, it is unique in that it is formed directly by enzymatic catalysis, a property which may also endow glu-lys crosslink formation with important intracellular functions. we found glutamic-lysine bonds to be present in the procaryote, escherichia coli, in primitive eucaryotes such as the s ... | 1979 | 427186 |
| fluctuations in proline and other free amino acids during the mitotic cycle of the myxomycete physarum polycephalum. | 1. during synchronous growth of the acellular slime mould physarum polycephalum the free amino pool had two maxima, one of 650 units [nmol/plasmodium dry weight (mg)] at metaphase and the other of 780 units in mid g2 with minima of 550 units before and after mitosis. 2. proline formed 20--25% of the total pool with aspartic acid, glutamic acid, threonine, valine, leucine, lysine and arginine making up 55% of the pool. 3. the fluctuation of proline during the mitotic cycle was quite different fro ... | 1979 | 436826 |
| distribution of inverted repeat sequences in nuclear dna from physarum polycephalum. | inverted repeat sequences, capable of forming stable intra-chain foldback duplexes, are shown using electron microscopy to be located in over 90% of fragments of nuclear dna from physarum polycephalum. a statistical treatment of the data indicates that, on average, foldback sequence foci are spaced every 7,000 nucleotides and that they are distributed uniformly amongst the dna chains. the majority of inverted repeat sequences give rise to the simple types of foldback structure observed in dna fr ... | 1979 | 436838 |
| temperature-sensitive mutants of physarum polycephalum: viability, growth, and nuclear replication. | using a selfing strain of physarum polycephalum that forms haploid plasmodia, we have isolated temperature-sensitive growth mutants in two ways. the negative selectant, netropsin, was used to enrich for temperature-sensitive mutants among a population of mutagenized amoebae, and, separately, a nonselective screening method was used to isolate plasmodial temperature-sensitive mutants among clonal plasmodia derived from mutagenized amoebae. complementation in heterokaryons was used to sort the mut ... | 1979 | 438137 |
| polyadenylated rna in the lower eukaryote physarum polycephalum. | utilizing a method which quantitatively extracts high molecular weight rna, including intact precursor as well as mature ribosomal rnas, adenylated molecules have been isolated from nuclear- and cytoplasmic-enriched fractions of physarum microplasmodia labeled with [3h]-uridine. electrophoretic analysis of denatured adenylated rna from the nuclear-enriched fraction indicated the presence of a population of large molecules not found in the cytoplasmic-enriched fraction. | 1979 | 440302 |
| dna replication in physarum polycephalum: electron microscopic and autoradiographic analysis of replicating dna from defined stages of the s-period. | electron microscopic and autoradiographic analysis of replicating dna from physarum showed that replication occurs at a rate of 0.4 micron/min/per replicon and that replicons of size 10--15 mu occur in temporal clusters with an average of about 4 replicons per cluster. these results are compared with previous hydrodynamic measurements and with those obtained in other organisms. | 1979 | 450701 |
| unique sequence arrangement of ribosomal genes in the palindromic rdna molecule of physarum polycephalum. | r-loop and restriction mapping procedures reveal the organization of coding regions at each end of the giant rdna palindrome of physarum polycephalum. a 19s coding region of 2.10 +/- 0.21 kb is located at each end of a very long central spacer (35.64 +/- 2.08 kb). an internal spacer of 1.66 +/- 0.12 kb lies distal to the 19s gene. the 5.8s rrna coding region is located in this spacer. the 26s gene lies distal to the internal spacer. the 26s gene is unusual among those of eukaryotes in that it co ... | 1979 | 450702 |
| inhibitory action of nephroma water extracts on the metabolism of physarum polycephalum. | | 1979 | 451053 |
| characterisation of ribosomal satellite in total nuclear dna from physarum polycephalum. | the distinctive properties of satellite dna molecules containing the genes for ribosomal rna in physarum polycephalum permits their identification in total, unfractionated nuclear dna in the foldback form, after denaturation and fast annealing. using the electron microscope the location and properties of three characteristic regions containing tandemly-repeated, inverted sequences have been investigated. at least two additional regions, also containing tandem repeats, are shown to be present and ... | 1979 | 454607 |
| physarum thymidine kinase. a step or a peak enzyme depending upon temperature of growth. | the variations of thymidine kinase or atp:thymidine 5'-phosphotransferase (ec 2.7.1.21) during the cell cycle of physarum polycephalum plasmodia have been studied at two extreme physiological temperatures: 22 degrees c and 32 degrees c. at 22 degrees c the enzyme activity increases near mitosis and stays constant during late s and g2 phases, exhibiting the typical pattern of a 'step enzyme'. but at 32 degrees c thymidine kinase activity goes through a maximum 1 h 30 min after mitosis and decreas ... | 1979 | 456364 |
| identification of mrna in the slime mold physarum polycephalum. | using a differential extraction procedure which had previously been shown to yield one nucleic acid fraction enriched in cytoplasmic rna and another enriched in nuclear rna, we have been able to isolate two polyadenylated rna populations from microplasmodia of physarum polycephalum. the poly(a)-containing rna from the cytoplasmic-enriched fraction accounts for approximately 1.2% of the cytoplasmic nucleic acid, has a number-average nucleotide size of 1339+/- 39 nucleotides, and has been shown, i ... | 1979 | 456382 |
| plasmalemma invaginations of physarum dependent on the nutritional content of the plasmodial environment. | quantitative estimates of plasmalemma invaginations in plasmodial veins of physarum polycephalum were made under different conditions of nutrition. pronounced differences were observed dependent on the nutritional content of the substrate. there was a decided increase in the number of plasmalemma invaginations in plasmodial veins grown on substrates containing absorbable food substances compared to veins migrating on non-nutrient substrates. this observation supports the proposition that the nut ... | 1979 | 457813 |
| kinetics of mating in physarum polycephalum. | | 1979 | 460299 |
| changes in cytoplasmic dna-binding phosphorproteins during the cell cycle of physarum polycephalum. | | 1979 | 466702 |
| studies on microplasmodia of physarum polycephalum v: electrical activity of different types of microplasmodia and macroplasmodia. | results obtained by three different electrophysiological methods delivered mainly oscillating potentials (independently of the type of organization of physarum polycephalum) with an average period length of 1 min 21 sec. this value is in good statistical agreement with corresponding data for the periodical oscillation of the shuttle streaming (1 min 47 sec) and coincides also with the radial tensiometric contractile activity (1 min 34 sec). the investigation favours the hypothesis that ion fluxe ... | 1979 | 476837 |
| the effect of growth on translation of polyadenylated messenger ribonucleic acid in physarum polycephalum [proceedings]. | | 1979 | 478124 |
| character and distribution of foldback sequences in nuclear deoxyribonucleic acid from physarum polycephalum [proceedings]. | | 1979 | 478125 |
| cycle specific association of nascent chromatin with nuclear envelope components in physarum polycephalum. | the action of heparin on isolated nuclei derived from different phases of the mitotic cycle in plasmodia of physarum polycephalum was studied. heparin addition at two-fold excess over dna concentration to nuclei in mg-free low ionic strength buffer (10 mm tris-hc1, 10 mm na2 hpo4, ph = 8) releases 60-80% of chromatin from s, g2, and mitotic phase nuclei. the rna/protein ratio of herparin-solubilized cromatin is constant through s and g2 phases, but rises about two-fold at early prophase coincide ... | 1979 | 482128 |
| repair of radiation-induced dna double-strand breaks in isolated nuclei of physarum polycephalum. | | 1979 | 482602 |
| ribosomes of physarum polycephalum. subunits and protein composition. | ribosomes from physarum polycephalum were purified. optimal conditions for preparation and stability of subunits were determined. kcl concentration above 200 mm induced protein dissociation from the subunits. it was observed that dissociated ribosomes were more stable in a low ionic strength buffer than in 200 mm kcl, where the 40 s was preferentially degraded by ribonucleases. ribosomal proteins were analyzed by two-dimensional gel electrophoresis. the first dimension was carried out at ph 8.6 ... | 1979 | 486531 |
| initiation of transcription of ribosomal deoxyribonucleic acid sequences in isolated nuclei of physarum polycephalum: studies using nucleoside 5'-[gamma-s]triphosphates and labeled precursors. | | 1979 | 497155 |
| specificity of sterol-glucosylating enzymes from sinapis alba and physarum polycephalum. | 1. sinapis alba l. seedlings contain glycosyltransferase catalyzing the synthesis of sterol glucosides in the presence of udpglucose as sugar donor. the major activity occurs in the membranous fraction sedimenting at 300--9000 x g. successive treatment of the particulate enzyme fraction with acetone and triton x-100 affords a soluble glucosyltransferase preparation which can be partly purified by gel filtration on sephadex g-150. molecular weight of the glucosyltransferase is 1.4 . 10(5). appare ... | 1979 | 497231 |