| 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 |
| effects of estremely low frequency electromagnetic fields on physarum polycephalum. | | 1976 | 945587 |
| 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 |
| mitotic delay in the slime mould physarum polycephalum induced by low intensity 60 and 75 hz electromagnetic fields. | | 1975 | 1167627 |
| structure of ribosomal dna in physarum polycephalum. | | 1976 | 988186 |
| mating type and the differentiated state in physarum polycephalum. | | 1975 | 1168600 |
| 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 |
| 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 |
| cycling aggregation patterns of cytoplasmic f-actin coordinated with oscillating tension force generation. | isometric contracting protoplasmic veins of physarum polycephalum show cycling patterns of cytoplasmic f-actin, dependent on their oscillating contraction behaviour (minute rhythms). the process of fibrillogenesis represents a parallel arrangement of f-actin chains ("plasma filaments, microfilaments") during the isometric contraction phase. a part of the results of the present work corroborates previous results on stretch-activated veins which showed that the fibrillar form of f-actin reflects t ... | 1976 | 942884 |
| a method of isolation of mitochondrial nucleoid of physarum polycephalum and evidence for the presence of a basic protein. | | 1976 | 942924 |
| multiple ornithine decarboxylase forms in physarum polycephalum: interconversion induced by cycloheximide. | | 1976 | 942930 |
| adenylate cyclases in physarum polycephalum: inhibition of a nuclear enzyme by polyamines. | | 1976 | 943166 |
| control of chemotaxis in physarum polycephalum. | plasmodia migrate towards those situations which increase the frequency of their alternations in streaming, and away from those which decrease the frequency. therefore peristalsis-like waves in physarum move in the direction opposite from the net movement of the organism. the mechanism is fundamentally related to other known types of chemotaxis. | 1976 | 943401 |
| structural comparison of deoxyribonucleic acid-dependent ribonucleic acid polymerases i and ii from the slime mold physarum polycephalum. | | 1976 | 944015 |
| levels of rna polymerases during the mitotic cycle of physarum polycephalum. | two rna polymerase activities were quantitatively solubilized in plasmodial homogenates from physarum polycephalum by sonication at 0.5 m ammonium chloride concentration. the proportions of rna polymerases a and b were determined by four different methods. equal activity levels of both enzyme a and enzyme b were detected throughout the synchronous mitotic cycle of physarum. | 1976 | 944051 |
| synthesis of ribosomal rna during the mitotic cycle on the slime mould physarum polycephalum. | 1. an isotope dilution technique has been used to analyze the synthesis of metabolically stable nucleic acids during the mitotic cycle in surface plasmodia of the slime mould physarum polycephalum. microplasmodia that had been labelled with [3h]uridine were used to prepare a surface culture, after a period of growth long enough to ensure that radioactivity was present only in trna, rrna and dna. the synthesis of rrna or nuclear dna during the growth of the surface plasmodium was then followed by ... | 1976 | 944125 |
| actomyosin content of physarum plasmodia and detection of immunological cross-reactions with myosins from related species. | the content of myosin in plasmodia of the myxomycete physarum polycephalum was measured by an immunological technique, quantitative microcomplement (c') fixation. migrating plasmodia (starved after growth on rolled oats) contained 0.60 +/- 0.08 (sd) mg myosin per g fresh plasmodia. myosin comprised 0.77% +/- 0.05 (sd) of the total plasmodial protein. when total plasmodial proteins were separated by electrophoresis on sds-polyacrylamide gels, a large amount of protein appeared in a band comigrati ... | 1976 | 944188 |
| thymidine kinase enzyme variants in physarum polycephalum; change of pattern during the synchronous mitotic cycle. | | 1976 | 1033088 |
| subunit structure of physarum polycephalum chromatin. | | 1976 | 945190 |
| 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 |
| effects of cordycepin on rna sythesis in physarum polycephalum. | | 1975 | 1079713 |
| contractile proteins. major components of nuclear and chromosome non-histone proteins. | two of the major non-histone proteins from physarum polycephalum have been isolated under nondenaturing conditions and identified as actin and myosin. a third protein has been purified from crude nuclear actomyosin and from residual nonhistone fractions and found to bind actomyosin in the presence of mg2+. in physarum these proteins are not components of the nuclear membrane. based on sodium dodecylsulfate-polyacrylamide gel electrophoresis, similar proteins are also present in nuclei of hela ce ... | 1975 | 1091294 |
| ribosomal rna genes in the amoebal and plasmodial forms of the slime mould physarum polycephalum. | 1. the degree of homology between ribosomal rna isolated from microplasmodia and amoebae of the slime mould physarum polycephalum has been determined by competive hybridisation of the rna from the two sources to homologous dna in solution. the extent of competition was measured both by hybridisation to saturation and by following the kinetics of hybrid formation. in each case competition was found to be 100%, indicating that the ribosomal rnas from the two, quite different vegetative forms of th ... | 1975 | 1097245 |
| [modern research on the cell cycle and mitosis in the myxomycete physarum polycephalum]. | the plasmodial stage of physarum polycephalum contains up to 10(9) nuclei which undergo a naturally synchronous mitosis every 8 h. nuclear processes such as dna and rna synthesis as well as many cytoplasmic processes such as histone synthesis are also synchronous. physarum polycephalum is therefore widely used in studies of cell-cycle events. this article describes experiments that may help to explain two fundamental biological processes: (1) the mechanism that triggers mitosis, (2) the structu ... | 1975 | 1105201 |
| covalent linkage between rna and nascent dna in the slime mold, physarum polycephalum. | when alpha--32 p-labeled deoxyribonucleoside triphosphates are injected into plasmodia of the eukaryotic slime mold, physarum polycephalum, they are incorporated initially into strands of dna which are mostly less than 300 nucleotides long. sixty minutes after injection incorporated deoxyribonucleoside triphosphates are found in much longer strands. if the short strands found two minutes after injection are denatured and centrifuged to equilibrium in a cs(2)so(4) density gradient, they migrate t ... | 1975 | 1168504 |
| some evidence for replication-transcription coupling in physarum polycephalum. | hydroxyurea, at concentrations of 40-60 mm, selectively and effectively blocked incorporation of thymidine into dna. inhibition occurred within 5-10 min of application of the agent when dna synthesis was in progress, while the onset of replication at the beginning of s-phase and dna synthesis in g2 phase were not affected. uridine incorporation into tca-precipitable material, in the presence of hydroxyurea, was significantly (up to 70%) inhibited in early s-phase of the cell cycle. selective inh ... | 1975 | 1170185 |
| sporulation-inducing factor in slime mould physarum polycephalum. | | 1975 | 1170501 |
| the effect of alfalfa saponins on growth and lysis of physarum polycephalum. | the prelytic events associated with the interaction of saponins with physarum polycephalum membrane components were studied. it was found that alfalfa saponins form interaction products with membranal sterols, proteins and phospholipids. the interaction of saponins with proteins affect also certain membranal enzymic activities such as nadh oxidase and malate dehydrogenase. it is suggested that although the interaction of the saponin with sterols is much more specific than with other membranal co ... | 1975 | 1171667 |
| [structure and histone composition of chromatin in physarum polycephalum]. | in physarum polycephalum several degrees of organisation of deoxyribonucleoprotein fibres were found. the complexes of histones and the dna duplex seem to "be packed" at first into a 100 a fibre and then into a 200 a fibre of dnp. in ph. polycephalum the electrophoretic mobilities of histone fractions 4 and 6 are comparable to that of fractions f3/f2b and f2a1 of calf thymus, resp. histone fractions 3 and 5 move a bit faster than fractions f1 and f2a2, resp. thus, the myxomycete p. polycephalum ... | 1975 | 1172312 |
| nuclear phosphoproteins of physarum polycephalum. characterization and phosphorus content of the phenol-soluble nuclear acidic proteins. | | 1975 | 1172412 |
| thermotaxis in a slime mold, physarum polycephalum. | | 1975 | 1172434 |
| dna replication by a possible continuous-discontinuous mechanism in homogenates of physarum polycephalum containing dextran. | nuclear dna synthesis in homogenates of physarum is greatly stimulated by the presence of dextran in the homogenizing medium. in this cell-free system, the dna precursor is incorporated approximately equally into two classes of dna intermediates. on of these is similar in size to that observed previously in the intact organism, i.e. its sedimentation rate in alkaline sucrose density gradients increases, presumably by chain elongation, as the organism progresses through the s phase. the other cla ... | 1975 | 1172449 |
| aminopeptidases of physarum polycephalum. activity, isoenzyme pattern, and synthesis during differentiation. | in extracts from both growing and differentiating (spherulating) plasmodia of the true slime mold physarum polycephalum, high aminopeptidase activities were found. the specificity of the aminopeptidases changed during differentiation with a higher relative activity towards hydrophobic nh2-terminal amino acids. this change in specificity was found to be the result of a shift in the isoenzyme spectrum during differentiation as was tested by isoelectric focusing in sucrose gradients. three differen ... | 1975 | 1172502 |
| life cycle variants of physarum polycephalum that lack the amoeba stage. | | 1975 | 1172631 |
| circular dna and rolling circles in nucleolar rdna from mitotic nuclei of physarum polycephalum. | 1. about 15% of nucleolar dna (1.712 g/cm3) from physarum polycephalum displaying maximum hybridization to ribosomal rna, is composed of circular dna of 3.9 +/- 0.2 mum contour length or multiples thereof. 2. a portion of these circular molecules (25%) contained linear dna pieces longer than circumference length. in a small fraction of circular dna linear pieces, shorter than the unit length, were observed. 3. most nucleolar dna, [3h]thymidine-labeled or hybridizable to ribosomal rna was separab ... | 1975 | 1236803 |
| dna breakage caused by dimethyl mercury and its repair in a slime mould, physarum polycephalum. | | 1975 | 1237092 |
| dna replication in physarum polycephalum: characterization of replication products in vivo. | synchronous plasmodia of physarum polycephalum in dna synthesis were pulse-labelled with [oh]- thymidine for time periods of 15 seconds up to 9 minutes, or given a 30 seconds pulse followed by chase periods of 9 minutes up to 6 hours. sedimentation analysis in alkaline sucrose gradients revealed at least five species of single stranded dna14 molecules in the pulse experiments. co-sedimentation of [14c]-labelled phage-dna gave relative s-values of 5-7, 13-15, 23-25, 30 and 33-35 for these dna mol ... | 1975 | 1237130 |
| premature replication of late s period dna regions in early s nuclei transferred to late s cytoplasm by fusion in physarum polycephalum. | fusion of a late s period plasmodium of physarum polycephalum to an early s period plasmodium causes premature replication of late s replicating regions in the nuclei of the early s plasmodium. the extent of ahead-of-schedule replication of late s replicating regions in early s period nuclei increases to a plateau of 16-20% for fusions with 40-70 min of phase difference, then declines for larger phase differences. the stimulatory factors for late s replicative units are present only in late s pl ... | 1975 | 1237322 |
| transmission and scanning electron microscopy of changes associated with microcyst formation in the myxamoebae of physarum polycephalum. | surface and internal changes associated with transition from myxamoebal to microcyst stages in physarum polycephalum have been observed with transmission and scanning electron microscopy. nuclear morphology, granules studded with ribosomal-like particles, synthesis of polysaccharides which are deposited exterior to the cell, and origin of material for the cell wall appear to be similar in the amoeba and in the plasmodium. in addition, the viability of the strain used in this research after being ... | 1975 | 1237391 |
| coordination of macromolecular synthesis in the slime mould physarum polycephalum. | microplasmodia of p. polycephalum were grown either in batch culture, in both complex and defined media to give a 3-4 fold variation in growth rate, or in a chemostate. the protein/dna ratio of batch cultures was almost invariant, whilst the rna/dna ratio increased as a non-linear function of growth rate. the amount of ribosomal rna, expressed as a fraction of total rna, showed little variation and this was also true for the proportion of ribosomes found in polyribosomes. calculation of the rat ... | 1975 | 1237783 |
| 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 |
| fluctuations in deoxyribo- and ribonucleoside triphosphate pools during the mitotic cycle of physarum polycephalum. | fluctuations in the pools of deoxyribo- and ribonucleoside triphosphates have been measured during the synchronous mitotic cycle of the slime mould physarum polycephalum. the most pronounced fluctuation of the deoxyribonucleoside triphosphates was seen shortly before and after initiation of dna synthesis. the pools of dttp, datp, dctp and dgtp expanded before initiation of dna synthesis and decreased again in early s phase. the pools of ribonucleoside triphosphates increased during mitosis and a ... | 1975 | 1238125 |
| the control of mitosis in physarum polycephalum. the effect of lowering the dna: mass ratio by uv irradiation. | | 1975 | 1238278 |
| calcium and magnesium contents of ectoplasm and endoplasm of physarum polycephalum plasmodium. | | 1975 | 1239055 |
| the amoebal cell of physarum polycephalum: colony formation and growth. | | 1975 | 1239390 |
| the mitotic oscillator in physarum polycephalum. | | 1975 | 1239646 |
| differential expression of rnase activities in the life cycle of physarum polycephalum. | | 1975 | 1240600 |
| [heat resistance of 2 types of protoplasmic movement in physarum polycephalum plasmodia]. | the thermostabilities of the "unordered" and shuttle protoplasmic streamings in myxomycete physarum polycephalum plasmodia was studied. a comparison of these thermostabilities has revealed that the cessation of the former streaming occurs at temperatures higher than those required for arresting the shuttle streaming. the difference between the two types of protoplasmic streamings is better seen in the rate of repair of protoplasmic streaming halted by a 10 minutes heating at 38-41 degrees c. for ... | 1975 | 1241623 |
| 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 |
| mapping of monoclonal antibody epitopes in the nucleolar protein fibrillarin (b-36) of physarum polycephalum. | we have mapped the epitopes for nine monoclonal antibodies raised against the nucleolar protein fibrillarin of the slime mold physarum polycephalum. this has been done using a combination of specific chemical and enzymatic cleavage, western blotting and partial sequencing of fragments. cleavage with cyanogen bromide reveals four prominent methionine cleavage sites within the protein. western blotting shows that none of the monoclonal antibody epitopes are dependent on long range interactions. ei ... | 1992 | 1283364 |
| reversible histone modifications and the chromosome cell cycle. | during the eukaryotic cell cycle, chromosomes undergo large structural transitions and spatial rearrangements that are associated with the major cell functions of genome replication, transcription and chromosome condensation to metaphase chromosomes. eukaryotic cells have evolved cell cycle dependent processes that modulate histone:dna interactions in chromosomes. these are; i) acetylations of lysines; ii) phosphorylations of serines and threonines and iii) ubiquitinations of lysines. all of the ... | 1992 | 1312335 |
| phosphorylation by actin kinase of the pointed end domain on the actin molecule. | fragmin from plasmodium of physarum polycephalum binds g-actin and severs f-actin in the presence of ca2+ over 10(-6) m. the fragmin-actin complex consisting of fragmin and g-actin nucleates actin polymerization and caps the barbed (fast growing) end of f-actin, regardless of the concentrations of ca2+, and the actin filaments are shortened. actin kinase purified from plasmodium abolishes the nucleation and capping activities of the complex by phosphorylating actin of the fragmin-actin complex ( ... | 1992 | 1315751 |
| the lysine-rich h1 histones from the slime moulds, physarum polycephalum and dictyostelium discoideum lack phosphorylation sites recognised by cyclic amp-dependent protein kinase in vitro. | calcium chloride-extracted histones were prepared from nuclei of the slime moulds, physarum polycephalum and dictyostelium discoideum, and phosphorylation by purified preparations of cyclic amp-dependent protein kinase (camp-d pk) and growth-associated h1 histone kinase (hkg) examined and compared. among the major histone fractions and other proteins in the two preparations, the h1 histones from both organisms were found to be effective and exclusive substrates for hkg. camp-d pk, which phosphor ... | 1992 | 1321059 |
| physarum actin is phosphorylated as the actin-fragmin complex at residues thr203 and thr202 by a specific 80 kda kinase. | the physarum egta-resistant actin-fragmin complex, previously named cap 42(a+b), is phosphorylated in the actin subunit by an endogenous kinase [maruta and isenberg (1983) j. biol. chem., 258, 10151-10158]. this kinase has been purified and characterized. it is an 80 kda monomeric enzyme, unaffected by known kinase regulators. staurosporine acts as a potent inhibitor. the actin-fragmin complex is the preferred substrate. the phosphorylation is inhibited by micromolar ca2+ concentrations, but onl ... | 1992 | 1324166 |
| intrinsic fluctuations of phosphoinositol levels are involved in the progression of the naturally synchronous cell cycle in physarum polycephalum. | using [3h]myo-inositol incorporation, changes in phosphoinositol (pi) metabolism at different cell cycle stages in the myxomycete physarum polycephalum were examined by column chromatography. two base levels for the inositol trisphosphate (ip3) fraction were determined: a low one for s-phase and a higher one for g2 phase. two transient increases of ip3 were also observed, one in s-phase, 70 min after mitosis (no g1 phase in the physarum cell cycle) and another in g2 phase, 90 min before mitosis. ... | 1992 | 1330570 |
| purification and partial characterization of transglutaminase from physarum polycephalum. | an intracellular form of calcium ion-dependent transglutaminase (r-glutaminylpeptide:amine gamma-glutaminyltransferase, ec 2.3.2.13) was purified 818-fold to apparent homogeneity from acetone powder preparations of spherules of the acellular slime mold physarum polycephalum. the enzyme was purified by combined methods of precipitation with 15% (wt/vol) polyethylene glycol, deae-cellulose chromatography, and isoelectric focusing in a ph 5 to 7 gradient. the isoelectric point of the enzyme was 6.1 ... | 1992 | 1348244 |
| structure and identity of a late-replicating and transcriptionally active gene. | eukaryotic genes are usually replicated early during s-phase in the cell lineages in which they are expressed. using partially characterized cdna probes, we recently established two exceptions to this rule in the slime mold physarum polycephalum. in this paper, we analyzed the structure and the identity of one of these two genes. by genomic cloning and southern analysis we demonstrate that it is a single-copy gene and decipher the structure of the two alleles by taking advantage of a restriction ... | 1992 | 1353456 |
| triterpenoid saponins from clinopodium polycephalum. | a new triterpenoid saponin, clinopodiside a, has been isolated from clinopodium polycephalum. its structure was established by spectroscopic methods and x-ray diffraction analysis as 3-o-beta-d-glucopyranosyl(1----6)-[ beta-d-glucopyranosyl (1----4)]-beta-d-glucopyranosyl-olean-11,13(18)-diene-3 beta,16 beta, 23,28-tetrol. | 1992 | 1368035 |
| physarum vitronectin-like protein: an arg-gly-asp-dependent cell-spreading protein with a distinct nh2-terminal sequence. | a 70-kda protein cross-reacted with anti-bovine vitronectin was isolated from slime mold physarum polycephalum. the nh2-terminal amino acid sequence of the protein, referred to as physarum vitronectin-like protein, did not share any homology with those of animal vitronectins. it had cell-spreading activity, which was specifically inhibited by an arg-gly-asp (rgd)-containing peptide. | 1992 | 1370938 |
| specific inhibition of physarum polycephalum dna-polymerase-alpha-primase by poly(l-malate) and related polyanions. | poly(l-malate) is an unusual polyanion found in nuclei of plasmodia of physarum polycephalum. we have investigated, by enzymatic and fluorimetric methods, whether poly(l-malate) and structurally related polyanions can interact with dna-polymerase-alpha-primase complex and with histones of p. polycephalum. poly(l-malate) is found to inhibit the activities of the dna-polymerase-alpha-primase complex and to bind to histones. the mode of inhibition is competitive with regard to dna in elongation and ... | 1992 | 1375154 |
| effects of fluorodeoxyuridine and nalidixic acid on the activity of topoisomerase i in plasmodia of physarum polycephalum. | 1. a regulatory coupling between the rate of cellular transcription and the activity of topoisomerase i was investigated in plasmodia of physarum polycephalum treated with fluorodeoxyuridine or nalidixic acid. 2. fluorodeoxyuridine at concentrations above 40 micrograms/ml lowered both the incorporation of [3h]uridine and the activity of topoisomerase i to 10% of corresponding control values. 3. nalidixic acid, in the range of concentrations between 20-50 micrograms/ml did not inhibit the incorpo ... | 1992 | 1379557 |
| structure and evolution of myxomycete nuclear group i introns: a model for horizontal transfer by intron homing. | we have examined five nuclear group i introns, located at three different positions in the large subunit ribosomal rna (lsu rrna) gene of the two myxomycete species, didymium iridis and physarum polycephalum. structural models of intron rnas, including secondary and tertiary interactions, are proposed. this analysis revealed that the physarum intron 2 contains an unusual core region that lacks the p8 segment, as well as several of the base-triples known to be conserved among group i introns. str ... | 1992 | 1394512 |
| characterization of calcium-binding light chain as a ca(2+)-receptive subunit of physarum myosin. | physarum myosin is uniquely under an inhibitory ca(2+)-regulation in the atp-dependent interaction with actin [kohama (1990) trends pharmacol. sci. 11, 433-435, for review]. calcium-binding light chain (calc) has been suggested to be of primary importance to the control from its amino acid sequence [kobayashi et al. (1988) j. biol. chem. 263, 305-313]. to provide a biochemical basis for this suggestion, the ca-binding capacity of calc and its kd for ca2+ were measured. the ca-binding properties ... | 1991 | 1663947 |
| inhibition of eukaryotic dna polymerase alpha with a novel lysophosphatidic acid (phylpa) isolated from myxoamoebae of physarum polycephalum. | a specific inhibitor of dna polymerase alpha was isolated from the lipid fraction prepared from myxoamoebae of a true slime mold, physarum polycephalum. the purified substance was subjected to structural studies by fast atom bombardment mass spectroscopy, infrared spectroscopy, and two-dimensional nuclear magnetic resonance spectroscopy. the structure of this substance was thereby suggested to be a novel lysophosphatidic acid (lpa) composed of cyclic phosphate and cyclopropane-containing hexadec ... | 1992 | 1400463 |
| microtubule organization by cross-linking and bundling proteins. | to understand microtubule function the factors regulating their spatial organization and their interaction with cellular organelles, including other microtubules, must be elucidated. many proteins are implicated in these organizational events and the known consequences of their actions within the cell are increasing. for example, the function of microtubule bundles at the surfaces of polarized cells has recently received attention, as has the action in cortical rotation of a transient arrangemen ... | 1992 | 1445941 |
| [physarum polycephalum-the model for biochemical investigations of the cell cycle (author's transl)]. | | 1975 | 1237883 |
| characterization of the self-splicing products of a mobile intron from the nuclear rdna of physarum polycephalum. | we have characterized the splicing products formed in vitro from rna derived from the mobile group i intron in the nuclear rdna of physarum polycephalum, pp lsu 3. this intron is a close relative of the well known tetrahymena intron tt lsu 1, being inserted at exactly the same position in the rdna and sharing about 90% sequence identity with tt lsu 1 in the conserved elements characteristic of the catalytic core of all group i introns. however, pp lsu 3 differs from tt lsu 1 in that it encodes a ... | 1992 | 1461722 |
| expression of a 66-kd heat shock protein associated with the process of cyst formation of a true slime mold, physarum polycephalum. | under unfavorable conditions for growth, haploid myxoamoebae of physarum polycephalum retracted their pseudopodia and changed their cell shape into disk-like form, after which they constructed the cell walls to form microcysts. these morphological changes of haploid cells were associated with changes in intracellular distribution of actin filaments. staining with phalloidin showed that actin filaments were almost uniformly distributed throughout the cytoplasm of the myxoamoebae. when these cells ... | 1992 | 1473160 |
| purification of a telomere-binding protein from physarum polycephalum. | we have purified a telomere-binding protein (ppt) from the acellular slime mold physarum polycephalum. as shown previously (coren, j.s., epstein, e.m. and vogt, v.m. (1991) mol. cell. biol. 11, 2282-2290), in vitro this protein binds specifically to the double stranded (ttaggg)n repeats that are found at the telomeres of extrachromosomal ribosomal dna from this organism, and also at telomeres of mammalian chromosomes. ppt was purified from physarum nuclear extracts by heat treatment at 90 degree ... | 1992 | 1482678 |
| a developmental mutation (npfl1) resulting in cell death in physarum polycephalum. | in physarum, microscopic uninucleate amoebae develop into macroscopic multinucleate plasmodia. in the mutant strain, ra614, plasmodium development is blocked. ra614 carries a recessive mutation (npfl1) in a gene that functions in sexual as well as apogamic development. in npfl+ apogamic development, binucleate cells arise from uninucleate cells by mitosis without cytokinesis at the end of an extended cell cycle. in npfl1 cultures, apogamic development became abnormal at the end of the extended c ... | 1992 | 1487727 |
| strain-dependent sequence heterogeneity in the nuclear group i introns and large subunit ribosomal rna in physarum polycephalum. | the dna sequence of an internal ecori fragment in the large subunit ribosomal rna gene from the myxomycete physarum polycephalum, strain m3c, has been determined. this ribosomal dna fragment contain two group i introns. sequence heterogeneity in the two introns and in the coding region of the ribosomal rna were identified upon comparison to the strain ppo-1 sequence. the nature of the sequence variations is discussed. | 1991 | 1818756 |
| dna polymerase alpha--primase complex of physarum polycephalum. | dna polymerase alpha and dna polymerase alpha--primase complex of physarum polycephalum were purified by rapid methods, and antibodies were raised against the complex. in crude extracts, immune-reactive polypeptides of 220 kda, 180 kda, 150 kda, 140 kda, 110 kda, 86 kda, 57 kda and 52 kda were identified. the structural relationships between the 220 kda, 110 kda and 140 kda (the most abundant form) was investigated by peptide mapping. the 140 kda form was active dna polymerase alpha. the 57 kda ... | 1992 | 1490277 |
| effects of tubulozole on the amoeboflagellate transformation in physarum polycephalum. | the amoeboflagellate transformation (aft) of physarum polycephalum involves rapid changes in the cytoskeleton, cell shape and cell motility. use of pharmacologic agents to probe the role of cytoskeletal elements in the aft are impeded because the transforming cells are very sensitive to such commonly-used drug solvents as dmso. the anti-microtubule agent tubulozole is found to disrupt, rapidly and transiently, the aft, inhibiting flagella formation, cell elongation and the arrangement of microtu ... | 1992 | 1490278 |
| cellular and molecular analysis of plasmodium development in physarum. | the development of an amoeba into a plasmodium involves extensive changes in cellular organisation and gene expression. the genetic basis of a number of recessive mutations that block plasmodium development has been elucidated. the stage at which development becomes abnormal has been determined for all the mutants, as has the terminal phenotype. in order to investigate the changes in gene expression that accompany plasmodium development, a cdna library has been made using rna isolated from cell ... | 1992 | 1490279 |
| methods for transient and stable expression of heterologous genes in physarum. | | 1992 | 1490280 |
| constitutive homologous recombination between mitochondrial dna and a linear mitochondrial plasmid in physarum polycephalum. | in one particular myxamoebal strain (ng7; mf+) of physarum polycephalum, a linear mitochondrial plasmid (mf plasmid) which promotes mitochondrial fusion has been identified. a mating between mf- strains, that do not carry the mf plasmid, resulted in uniparental inheritance of the mtdna. in matings between mf+ and mf- strains a recombination occurred between the mtdna and the mf plasmid, and recombinant mtdna was generated with the end of the mf plasmid as its ends. the dna sequences of the recom ... | 1992 | 1525874 |
| regulation by ca(2+)-calmodulin of the actin-bundling activity of physarum 210-kda protein. | from the plasmodia of a lower eukaryote, physarum polycephalum, we have previously purified a 210-kda protein that showed similar properties to those of smooth muscle caldesmon. further characterization of the 210-kda protein revealed that it bundled actin filaments. this bundling activity was inhibited by calmodulin in the presence of ca2+. unlike smooth muscle caldesmon, the 210-kda protein bundled actin filaments whether or not a reducing agent, such as dithiothreitol, was present. the protei ... | 1992 | 1527219 |
| model of the ca2+ oscillator for shuttle streaming in physarum polycephalum. | we propose a mechanism for the cytoplasmic ca++ oscillator which is thought to power shuttle streaming in strands of the slime-mold physarum polycephalum. the mechanism uses a phosphorylation-dephosphorylation cycle of myosin light chain kinase. this kinase is bistable if the kinase phosphorylation chain, through adenylate cyclase and camp, is activated by calcium. relaxation oscillations can then occur if calcium is exchanged between the cytoplasm and internal vacuoles known to exist in physaru ... | 1992 | 1532135 |
| mechanisms of cell shape change: the cytomechanics of cellular response to chemical environment and mechanical loading. | processes such as cell locomotion and morphogenesis depend on both the generation of force by cytoskeletal elements and the response of the cell to the resulting mechanical loads. many widely accepted theoretical models of processes involving cell shape change are based on untested hypotheses about the interaction of these two components of cell shape change. i have quantified the mechanical responses of cytoplasm to various chemical environments and mechanical loading regimes to understand bett ... | 1992 | 1556158 |
| preferential expression of one beta-tubulin gene during flagellate development in physarum. | the microbial eukaryote physarum polycephalum displays several distinct cell types in its life cycle, including amoebae, flagellates and plasmodia. despite its relative simplicity, physarum has a tubulin gene family of complexity comparable to that of drosophila. we have identified beta-tubulin cdnas from physarum that are derived from the beta beta-tubulin locus and encode beta 1a tubulin. we have also identified a partial cdna for the unlinked betb beta-tubulin gene, which encodes beta 1b tubu ... | 1992 | 1556551 |
| intrinsically bent dna flanks both sides of an rna polymerase i transcription start site. both regions display novel electrophoretic mobility. | we have identified two intrinsically bent regions of dna which flank the transcription start site of the rrna gene from physarum polycephalum. dna fragments from both regions were analyzed by circular permutation polyacrylamide gel electrophoresis assay and computer modeling. both types of analysis indicate that one fragment contains a relatively simple bend centered about 160 base pairs (bp) upstream of the transcription start site while the other fragment contains multiple bends, the most prom ... | 1992 | 1577826 |
| actin kinase: a protein kinase that phosphorylates actin of fragmin-actin complex. | actin of fragmin-actin complex is phosphorylated by an endogenous kinase from plasmodium of physarum polycephalum. the phosphorylation abolishes the nucleation and capping activities of fragmin-actin complex. the kinase has been purified and termed actin kinase [furuhashi, k. & hatano, s. (1990) j. cell biol. 111, 1081-1087]. enzymatic properties of the purified actin kinase were studied in detail. actin kinase exhibited the highest activity under conditions physiological for the plasmodium (30 ... | 1992 | 1587799 |
| isolation and partial characterization of haemagglutinins from plasmodia of physarum polycephalum. | the soluble haemagglutinins produced by plasmodia of physarum polycephalum were purified by chromatographic methods and resolved into haemagglutinins i and ii. on sds-page, purified haemagglutinins i and ii each gave a single band with an apparent molecular mass of 6 and 11 kda, respectively. the results of gel-filtration chromatography suggested that both haemagglutinins were dimers of the respective subunits under non-denaturing conditions. rabbit erythrocytes were preferentially agglutinated ... | 1992 | 1593267 |
| monofunctional dna-platinum(ii) adducts block frequently dna polymerases. | the question of whether monofunctional dna platinum(ii) adducts block synthesis of dna by purified dna polymerases of different types and origin has been investigated by comparing the time dependence of synthesis arrest and of dna adduct formation. activated salmon testis dna is used as a suitable substrate for dna synthesis allowing to probe inhibition by platinum(ii) monoadducts for the variety of inherent template-primers. reaction amplitudes are related to defined mixtures of dichloro and ch ... | 1992 | 1594449 |
| chromosomal proteins of physarum polycephalum with preferential affinity for the sequence, poly d(a-t).poly d(a-t). | we have identified two novel chromosomal proteins from physarum polycephalum using a protein blotting dna-binding assay. a fraction of these proteins was readily released from nuclei by solutions of moderate ionic strength (0.15 n-0.35 m nacl) or mild nuclease treatment and appear associated with chromatin that is nucleosome-free. a significant proportion of these proteins, however, was not released from nuclei by solutions of high ionic strength (1.6 m nacl) or treatment with excess nuclease. t ... | 1992 | 1608398 |
| mapping of a physarum chromosomal origin of replication tightly linked to a developmentally-regulated profilin gene. | we compared the pattern of replication of two cell-type specific profilin genes in one developmental stage of the slime mold physarum polycephalum. taking advantage of the natural synchrony of s-phase within the plasmodium, we established that the actively transcribed profilin p gene is tightly linked to a chromosomal replication origin and is replicated at the onset of s-phase. in contrast, the inactive profilin a gene is not associated with a replication origin and it is duplicated in mid s-ph ... | 1992 | 1630902 |
| cell cycle-dependent assembly and disassembly of cytoplasmic microtubules in the plasmodium of the myxomycete physarum polycephalum. | the giant syncytium of physarum plasmodia possesses a complex cytoplasmic microtubule network except during the occurrence of the intranuclear mitosis. in early prophase stages, intranuclear spindles assemble concomitantly as the cytoplasmic microtubule network disassembles. no cytoplasmic microtubules are present in metaphase. they begin to reassemble in telophase. the complex cytoplasmic microtubule network reappears in early reconstruction stages. the assembly of cytoplasmic microtubules occu ... | 1992 | 1644060 |
| inhibitory ca(2+)-regulation of myosin light chain kinase in the lower eukaryote, physarum polycephalum: role of a ca(2+)-dependent inhibitory factor. | atp-dependent interactions between myosin and actin in the lower eukaryote, physarum polycephalum, are inhibited by micromolar levels of ca2+. this inhibition is mediated by the binding of ca2+ to myosin, the phosphorylation of which is required if ca2+ is to inhibit the activities of myosin (kohama, k., trends pharmacol. sci. 11, 433-435 (1990)). as the first step to examine whether ca2+ also regulates phosphorylation in the actomyosin system, we purified myosin light chain kinase (mlck) of 55 ... | 1991 | 1666040 |
| rapid disappearance of one parental mitochondrial genotype after isogamous mating in the myxomycete physarum polycephalum. | five haploid amoebal strains of the myxomycete physarum polycephalum, each with a distinct mitochondrial genotype, were crossed in all pairwise combinations. the mitochondrial genotype in the diploid plasmodia resulting from these isogamous matings were found to be transmitted uniparentally. this uniparental inheritance could be arranged in a dominant hierarchical order. time-course analysis of the presence of mitochondrial genotypes in the zygotes and young developing plasmodia show that elimin ... | 1991 | 1674675 |
| localization by high resolution in situ hybridization of the ribosomal minichromosomes during the nucleolar cycle of physarum polycephalum. | we have used biotinylated rdna probes to localize by in situ hybridization the extrachromosomal genes for ribosomal rna in the slime mold physarum polycephalum. we established conditions that allow for highly specific hybridization at the ultrastructural level and determined that the 60-kb palindromic rdna molecules are confined to the nucleolus in interphase. our study definitively locates these extrachromosomal genes in mitosis in the form of thin dna fibers contained within nucleolar remnants ... | 1992 | 1459200 |