Publications

physical properties and chemical compositions of cytoplasmic and mitochondrial malate dehydrogenase from physarum polycephalum.	the malate dehydrogenase isoenzymes from physarum polycephalum have been purified to homogeneity as confirmed by gel filtration chromatography, polyacrylamide gel disc electrophoresis and analytical ultracentrifugation. certain physical and chemical parameters of the malate dehydrogenase isoenzymes reported here include sedimentation, molecular weight and subunit molecular weight. most unique of the differences between the isoenzymes were the widely separate isoelectric points of 9.83 for mitoch ...	1976	945747
chemotaxis in physarum polycephalum. effects of chemicals on isometric tension of the plasmodial strand in relation to chemotactic movement.		1976	945771
subunit structure of chromosomes in mitotic nuclei of physarum polycephalum.	we have investigated the subunit structure of mitotic chromosomes of the acellular slime mould physarum polycephalum, using the nuclease susceptibility of isolated mitotic nuclei as a probe. a characteristic pattern of dna digestion products is obtained, containing approximately integral multiples of a basic 140 base pair dna segment that resembles very closely the pattern in g2 phase nuclei of physarum and of calf lymphocyte nuclei. these results demonstrate that during the process of chromosom ...	1976	986286
effects of cycloheximide on thymidine metabolism and on dna strand elongation in physarum polycephalum.		1976	986475
apogamic development of plasmodia in the myxomycete physarum polycephalum: a cinematographic analysis.		1976	987603
differential template specificities of nuclear rna polymerases isolated from physarum polycephalum.		1976	987753
organisation of genes for ribosomal rna in physarum polycephalum.	physarum polycephalum nucleolar satellite dna has been analysed by restriction enzyme digests and hybridisation to ribosomal rna. the nucleolar dna is isolated as molecules of molecular weight 39 x 10(6). the positions of sites of endo r-ecori and endo r-hindiii digestion have been determined accurately in the whole molecule. the endo r-ecori sites and one endo r-hindiii site are within the26-s rrna complementary sequence and the other endo r-hindiii site is within the 19-s rrna complementary se ...	1976	987907
structure of ribosomal dna in physarum polycephalum.		1976	988186
transformation of cytoplasmic actin. importance for the organization of the contractile gel reticulum and the contraction--relasation cycle of cytoplasmic actomyosin.	(1) within the low viscous flowing endoplasm of physarum polycephalum a considerable amount of actin is in the non-filamentous state. this can be demonstrated by applying poly-l-lysin to surface spreads of native protoplasm. (2) it has been shown that in protoplasmic drops the endoplasm-ectoplasm transformation is accompanied by an actin polymerization from the non-filamentous state to f-actin. (3) the actual state of the labile g-f-actin equilibrium determines the varying consistency (viscosity ...	1976	1033037
the uptake and metabolism of uridine by the slime mould physarum polycephalum.	1. uridine is taken up by microplasmodia of physarum polycephalum via a saturatable transport system with an apparent km of 29 mum. an intracellular concentration significantly higher than that in the growth medium is attained, suggesting that the uptake is an active process. both deoxyribonucleosides and ribonucleosides are competitive inhibitors of the uptake of uridine. 2. in contrast, the rate of entry of uridine into surface plasmodia is a linear function of the concentration of the nucleos ...	1976	1033062
cytoplasmic dna-binding phosphoproteins of physarum polycephalum.		1976	1033079
thymidine kinase enzyme variants in physarum polycephalum; change of pattern during the synchronous mitotic cycle.		1976	1033088
sterol content of the myxomycetes physarum polycephalum and p. flavicomum.	the sterol content of two myxomycetes, physarum polycephalum and p. flavicomum has been examined. the sterols of the two species are apparently identical, the two major sterols in each being poriferasterol and 22-dihydroporiferasterol. threee minor sterols are probably delta5-ergostenol, ergostanol, and poriferastanol. the triterpenoids of the two species differ in that, though lanosterol was identified in both, 22-dihydrolanosterol was indicated only in p. flavicomum. the occurrence of lanoster ...	1976	1033261
the subunit structure of chromatin from physarum polycephalum.	nucleosome dna repeat lengths in physarum chromatin, determined by nuclease digestion experiments, are shorter than those observed in most mammalian chromatin and longer than those reported for chromatin of certain other lower eukaryotes. after digestion with staphylococcal nuclease for short periods of time an average repeat length of 190 base pairs is measured. after more extensive digestion an average repeat length of 172 base pairs is measured. upon prolonged digestion dna is degraded to an ...	1976	1034293
a cytoplasmic inhibitor of dna polymerase from the plasmodia of physarum polycephalum.	a factor which inhibited dna polymerase [ec 2.7.7.7] activity was isolated from the cytoplasm of plasmodia of true slime mold, physarum polycephalum. this factor was purified by deae-sephadex and cm-cellulose column chromatographies, heat treatment and gel filtration. this inhibitor was heat-stable, insensitive to trypsin [ec 3.4.21.4] and was not digested by rnase [ec 3.1.4.22] or dnase [ec 3.1.4.5]. the molecular weight was 16,000 as determined by gel filtration, and the isoelectric point was ...	1976	1034631
photoreceptor pigment that induces differentiation in the slime mold physarum polycephalum.	an extract of small molecules (molecular weight less than 500) of the slime mold physarum polycephalum undergoes a shift in ultraviolet-visible absorption spectrum upon illumination. this illumination also confers on the extract the ability to induce sporulation when injected into a starved, unilluminated slime mold. the spectral shift and appearance of the sporulation-inducing activity both occur regardless of whether the illumination is carried out on an intact slime mold or on the plasmodium- ...	1976	1069274
oscillations of calcium ion concentrations in physarum polycephalum.	aequorin is a photoprotein which emits light in response to changes in free calcium concentration. when aequorin was microinjected into plasmodia of physarum polycephalum, light emission varied in synchrony with the motile oscillations of the organisms. therefore, movement is correlated which changes in the concentration of free calcium.	1976	1254647
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
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
[acid phosphomonoesterase of physarum polycephalum].		1976	71055
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
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
myxobacters from arid mexican soil.	myxobacters were found to be common inhabitants of the arid soils from the monterrey, nuevo leon, mexico, area. thirteen species of the genera myxococcus, archangium, cystobacter, stigmatella, polyangium, and chondromyces were isolated on a mineral salts agar supplemented with bakers' yeast and filter paper. greater species diversity per soil sample was found in the region receiving 400 to 800 mm of annual rainfall as compared with soils from an area having only 200 to 400 mm of rainfall.	1976	16345178
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
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
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
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
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
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
synthesis of protein during the nuclear division cycle in physarum polycephalum.		1977	563805
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
calcium uptake during mitosis in the myxomycete physarum polycephalum.		1977	917106
use of specific endonuclease cleavage in rna sequencing-an enzymic method for distinguishing between cytidine and uridine residues.	the extracellular ribonuclease i of the common slime mold physarum polycephalum (rnase phy1), which has recently been purified to homogeneity, has been used to distinguish between c and u residues in 3'-end-labeled oligoribonucleotides. as shown by bargetzi and coworkers, this enzyme exhibits strong cleavage preference for u-n over c-n and n-c over n-u bonds. in the present paper, conditions are being detailed, which enable one to deduce the sequences of rather large, pyrimidine-rich, terminally ...	1977	928065
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
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
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
mutations increasing asexual plasmodium formation in physarum polycephalum.	rare plasmodia formed in clones of heterothallic amoebae were analyzed in a search for mutations affecting plasmodium formation. the results show that the proportion of mutants varies with both temperature (18 degrees , 26 degrees or 30 degrees ) and mating-type allele (mt1, mt2, mt3, mt4). at one extreme, only one of 33 plasmoida formed by mt2 amoebae at 18 degrees is mutant. at the other extreme, three of three plasmodia formed by mt1 amoebae at 30 degrees are mutant. the mutant plasmodia fall ...	1977	17248771
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