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enzymes involved in the dynamic equilibrium of core histone acetylation of physarum polycephalum.deae-sepharose chromatography of extracts from plasmodia of the myxomycete physarum polycephalum revealed the presence of multiple histone acetyltransferases and histone deacetylases. a cytoplasmic histone acetyltransferase b, specific for histone h4, and two nuclear acetyltransferases a1 and a2 were identified; a1 acetylates all core histones with a preference for h3 and h2a, whereas a2 is specific for h3 and also slightly for h2b. two histone deacetylases, hd1 and hd2, could be discriminated. ...19921730297
dictyostelium discoideum essential myosin light chain: gene structure and characterization.we have used a dictyostelium essential myosin light chain (emlc) cdna clone to isolate additional cdna clones which supply a different 3' sequence from that previously described. the revised cdna sequence encodes a polypeptide of 150 amino acids. amino acid residues 147-167 of the previously reported sequence are replaced by new residues 147 to 150. the new cdna encodes a polypeptide with 66% amino acid sequence identity with the physarum polycephalum emlc, and approximately 30% identity with ma ...19911751970
differential effect of cordycepin on s and g2 phases of cell cycle in plasmodia of physarum polycephalum schw.effect of pulse treatments of cordycepin, an analog of adenosine, on s and g2 phases of the cell cycle of the mitotically synchronous plasmodia of physarum polycephalum has been studied. various concentrations of the drug (50-200 micrograms ml-1) were found to be effective in delaying mitosis by several hours in both the phases. however, there was a significant increase in mitotic delay in those treated during g2. it is suggested that this extra delay during g2 could be due to the transcriptive ...19911794860
physarum plasmodia do contain cytoplasmic microtubules!it has been claimed that the plasmodium of the myxomycete physarum polycephalum constitutes a very unusual syncytium, devoid of cytoplasmic microtubules. in contrast, we have observed a cytoplasmic microtubule network, by both electron microscopy and immunofluorescence in standard synchronous plasmodia, either in semi-thin sections or in smears, and in thin plasmodia, used as a convenient model. cytoplasmic microtubules could be seen after immunofluorescent staining with three different monospec ...19911808203
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.19911818756
rna editing by cytidine insertion in mitochondria of physarum polycephalum.a corollary of the central dogma of molecular biology is that genetic information passes from dna to rna by the continuous synthesis of rna on a dna template. the demonstration of rna editing (the specific insertion, deletion or substitution of residues in rna to create an rna with a sequence different from its own template) raised the possibility that in some cases not all of the genetic information for a trait residues in the dna template. two different types of rna editing have been identifie ...19911825131
stimulation of the interaction between actin and myosin by physarum caldesmon-like protein and smooth muscle caldesmon.we have purified an actin-binding protein from the plasmodia of a lower eukaryote, physarum polycephalum, with an apparent molecular mass of 210,000 daltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. this protein bound to actin filaments with a stoichiometry of 1:7-8 in a ca(2+)-calmodulin-dependent manner. antibody raised against caldesmon from smooth muscle cross-reacted with the 210-kda protein. in vitro motility assay revealed that the 210-kda protein increased the sliding ...19911834662
[calcium inhibition, a new mode for ca2+ regulation].the intracellular concentration of ca2+ ([ca2+]i) in eukaryotic cells is low under resting conditions. membrane stimulation can produce a transient increase in [ca2+]i from submicromolar to micromolar levels. classically, the effects of elevated [ca2+]i on eukaryotic cell responses are excitatory: they induce muscle contraction or activate metabolic systems. however, micromolar concentration of ca2+ has been found to inhibit the actin-myosin-atp interaction of the lower eukaryote physarum polyce ...19911835954
role of actin in the myosin-linked ca(2+)-regulation of atp-dependent interaction between actin and myosin of a lower eukaryote, physarum polycephalum.actin-activated atpase activity of myosin from physarum polycephalum decreases when it binds ca2+ and increases when it loses ca2+. this ca-inhibition is observed with phosphorylated myosin [kohama, k. (1990) trend, pharmacol. sci. 11, 433-435]. the activity of dephosphorylated myosin remained at a low level both in the presence and absence of ca2+, although ca(2+)-binding ability was much the same as that of the phosphorylated myosin. the effect of phosphorylation has been studied at a conventi ...19911838110
an unusual actin-encoding gene in physarum polycephalum.actin is one of the most conserved proteins in eukaryotic organisms. in the present work, we cloned and determined the nucleotide sequence of an unusual actin-encoding gene, ardd, from the slime mold, physarum polycephalum. the ardd gene encodes an ardd protein containing 367 amino acids (aa) instead of the 375-376 aa found in a typical actin. the nine missing aa are accounted for by deletions of three aa in the first exon, five in the fifth exon and one in the sixth exon. these deletions in the ...19911840544
topoisomerase i in actively growing plasmodia and during differentiation of the slime mold physarum polycephalum.a type i topoisomerase has been purified from nuclei of a slime mold physarum polycephalum and its activity was tested during spherulation. the final preparation contained a single polypeptide of about 100 kda. basic properties of physarum topoisomerase i (substrate specificity, ionic requirement, sensitivity to inhibitors) were similar to those of topoisomerases from higher eukaryotes. specific features of physarum enzyme were that it was rapidly inactivated at 45 degrees c and did not react wi ...19911846567
a continuum model of contraction waves and protoplasm streaming in strands of physarum plasmodium.we present a mathematical model for continuously distributed mechanochemical autooscillations (autowaves) in a protoplasmic strand of physarum polycephalum. the model is based on a hypothesis of local positive feedback between deformation and contraction of the contractile apparatus. this feedback is mediated through a cell regulatory system whose kinetics involves coupling to mechanical strain. mathematical analysis and computer simulations have demonstrated that the solutions of the model agre ...19911863716
adp-ribosylation of core histones and their acetylated subspecies.adp-ribosylation of core histones was investigated in isolated nuclei of physarum polycephalum. core histone species differed in the mode of modification. whereas adp-ribosylation of h2a and h2b is sensitive to inhibition by 3-methoxybenzamide, as with most other nuclear acceptor proteins, the modification of h3 and h4 is not inhibited. cleavage experiments with hydroxylamine indicate a carboxylate ester type adp-ribose-protein bond for h2a and h2b and arginine-linked adp-ribose residues for h3 ...19911872796
synergistic effect of heat-shock and uv-irradiation on mitosis and protein synthesis in g2-phase plasmodia of physarum polycephalum schw--reduction in uv-induced mitotic delay in a preheat-shocked system.the synergistic effect of uv irradiation and heat-shock during the last 3 hr of g2 phase of the cell cycle in the plasmodia of p. polycephalum, in terms of mitotic delay and inhibition of protein synthesis, has been evaluated. the mitotic delay due to both perturbers coordinately increased closer to mitosis. maximum mitotic delay was obtained in plasmodia heat-shocked after uv irradiation, indicating the presence in this system of either a heat-labile mitogenic substance which is comparatively l ...19911874549
isolation, characterisation and growth-related changes of an hmg-like protein from microplasmodia of physarum polycephalum.an alanine, lysine and glutamic acid-rich nuclear protein (p2) of mr approximately 19,500 co-extracts with the histones from nuclei of physarum polycephalum when using the cacl2 method for histone extraction [1] and was found to have the composition previously ascribed to a putative histone h1(0) isolated from microplasmodia using 5% pca (yasuda, h., mueller, r.d., logan, k.a. and bradbury, e.m. (1986) j. biol. chem. 261, 2349-2354). p2 has very similar electrophoretic properties to chicken eryt ...19911888760
f-actin bundling protein from physarum polycephalum: purification and its capacity for co-bundling of actin filaments and microtubules.an f-actin bundling protein was isolated and purified from plasmodium of physarum polycephalum. the f-actin bundling protein in physarum extract was passed through a deae-cellulose column. after the protein in the fraction was treated with 6 m urea, it was purified by gel filtration on sephacryl s-300 hr followed by chromatography on cm-toyopearl (cation exchange) in the presence of 6 m urea. the purified protein gave a single band on sds-page, and the molecular weight was estimated to be 52,000 ...19911934085
evolution. sex, slime and selfish genes. 19911944565
physical relationship between a gene and its origin of replication in physarum polycephalum.taking advantage of the natural synchrony of the s-phase within the plasmodium of physarum polycephalum, we extracted highly synchronous dna samples at precise time points in early s-phase. we then separated, by electrophoresis under denaturating conditions, the newly synthesized dna strands of the nascent chromosomal replicons from the parental dna template. using the cdna clone of the early-replicating lav1-2 gene as a probe, we could establish by filter hybridization that the elongation rate ...19901967581
immunologically-related nucleic acid-binding proteins associated with the nuclear matrix of physarum polycephalum.the nuclear matrix of physarum polycephalum is composed of two abundant polypeptides of 27 and 38 kda as well as numerous minor polypeptides of various molecular weight. by contrast, the nuclear matrix of vertebrates consists of three major (the lamins) and many minor polypeptides mainly in the 60-70 kda molecular weight range. in order to better characterize the major nuclear matrix proteins of p. polycephalum and, perhaps, define their relationship with the major nuclear matrix proteins of ver ...19911989695
cell cycle dependent association of c-myc protein with the nuclear matrix.we demonstrate the presence of a c-myc protein with an apparent molecular weight of 67 kd in the lower eukaryote physarum polycephalum with polyclonal and monoclonal anti-c-myc-antibodies. it is shown that the amount of myc protein present in the nucleus does not fluctuate during the naturally synchronous cell cycle of physarum. the myc protein remains firmly associated with the nuclear matrix after a variety of matrix preparation procedures. although the level of c-myc protein is invariant duri ...19911992443
characterization of a telomere-binding protein from physarum polycephalum.we have partially purified a nuclear protein (ppt) from physarum polycephalum that binds to the extrachromosomal ribosomal dna telomeres of this acellular slime mold. binding is specific for the (t2ag3)n telomere repeats, as evidenced by nitrocellulose filter binding assays, by gel mobility shift assays with both dna fragments and double-stranded oligonucleotides, and by dnase i footprinting. ppt is remarkably heat stable, showing undiminished binding activity after incubation at 90 degrees c. i ...19912005910
variable pathways for developmental changes of mitosis and cytokinesis in physarum polycephalum.the development of a uninucleate ameba into a multinucleate, syncytial plasmodium in myxomycetes involves a change from the open, astral mitosis of the ameba to the intranuclear, anastral mitosis of the plasmodium, and the omission of cytokinesis from the cell cycle. we describe immunofluorescence microscopic studies of the amebal-plasmodial transition (apt) in physarum polycephalum. we demonstrate that the reorganization of mitotic spindles commences in uninucleate cells after commitment to pla ...19912016339
purification of a novel ca-binding protein that inhibits myosin light chain kinase activity in lower eukaryote physarum polycephalum.myosin light chain kinase (mlck) was partially purified from the lower eukaryote physarum polycephalum. the activity to phosphorylate physarum myosin was maximal in the absence of ca2+ and decreased with an increase in ca2+ concentration with a microm-level kd. the ca-binding protein contained in the mlck preparation was purified to homogeneity. the native protein had a molecular mass of 75 kda, while under denaturing conditions, it was 38 kda. ca-dependent changes in the intensities of intrinsi ...19912025271
a phylogenetic study of u4 snrna reveals the existence of an evolutionarily conserved secondary structure corresponding to 'free' u4 snrna.the nucleotide sequence of physarum polycephalum u4 snrna*** was determined and compared to published u4 snrna sequences. the primary structure of p polycephalum u4 snrna is closer to that of plants and animals than to that of fungi. but, both fungi and p polycephalum u4 snrnas are missing the 3' terminal hairpin and this may be a common feature of lower eucaryote u4 snrnas. we found that the secondary structure model we previously proposed for 'free' u4 snrna is compatible with the various u4 s ...19912031956
division of physarum mitochondria during starvation.microplasmodia of physarum polycephalum used in this study form spherules after 18 h of starvation. stereological morphometry revealed that between the 2nd and the 5th hour of starvation the number of mitochondria in 1 mm3 of cytoplasm rises from about 12 to 24 millions and the mean volume of mitochondria drops from circa 4.6 to 3.0 microns3. this denotes the synchronous division of mitochondria. the daughter mitochondria show an increase in density of the matrix and a decrease in condensation o ...19912032291
homologies between members of the germin gene family in hexaploid wheat and similarities between these wheat germins and certain physarum spherulins.by screening approximately 10(6) plaques in a wheat dna library with a "full-length" germin cdna probe, two genomic clones were detected. when digested with ecori, one clone yielded a 2.8-kilobase pair fragment (gf-2.8) and the other yielded a 3.8-kilobase pair fragment (gf-3.8). by nucleotide sequencing, each of gf-2.8 and gf-3.8 was found to encode a complete sequence for germin and germin mrna, and to contain appreciable amounts of 5'- and 3'-flanking sequences. the "cap" site in gf-2.8 was d ...19912037593
polypeptides from the myxomycete physarum polycephalum interacting in vitro with microtubules.microtubule-interacting proteins have been studied in the lower eukaryote physarum polycephalum. we show for the first time 1) the presence in physarum amoebal crude extracts of at least six polypeptides that bind specifically to amoebal microtubules, 2) the binding between these proteins and mammalian microtubules, 3) the heat stability of two of these polypeptides (125 and 235 kda), 4) the functional properties of a fraction containing a heat-soluble 125 kda polypeptide, and 5) the phosphoryla ...19902076544
evolution of a protein superfamily: relationships between vertebrate lens crystallins and microorganism dormancy proteins.a search of sequence databases shows that spherulin 3a, an encystment-specific protein of physarum polycephalum, is probably structurally related to the beta- and gamma-crystallins, vertebrate ocular lens proteins, and to protein s, a sporulation-specific protein of myxococcus xanthus. the beta- and gamma-crystallins have two similar domains thought to have arisen by two successive gene duplication and fusion events. molecular modeling confirms that spherulin 3a has all the characteristics requi ...19902107329
differential synthesis of histone h1 during early spherulation in physarum polycephalum.h1 and p2 (an h1 degree/hmg-like protein) accumulate during exponential growth of physarum microplasmodia (unpublished results), indicating that these proteins may play a role in differentiation (spherulation). to test this hypothesis, pulse labelling using [14c]lysine was used to determine whether any differential histone synthesis occurs during salts-induced spherulation. a peak in the uptake of [14c]lysine into microplasmodia was detected between 12 and 24 h following salts-induction. during ...19902114182
cell cycle regulation of p34cdc2 kinase activity in physarum polycephalum.the regulation of the mitotic histone h1 kinase activity has been analyzed during the naturally synchronous cell cycle of physarum polycephalum plasmodia. the universal binding property of the p13suc1 schizosaccharomyces pombe gene product was used to precipitate and assay the cdc2 histone h1 kinase activity. the kinase activity peaks at the beginning of metaphase and its decline, which requires protein synthesis, appears to be an early event during the metaphase process. microtubular poisons, t ...19902126544
regulation of tubulin synthesis during the cell cycle in the synchronous plasmodia of physarum polycephalum.regulation of alpha- and beta-tubulin isotype synthesis during the cell cycle has been studied in the myxomycete physarum polycephalum, by subjecting synchronous plasmodia to temperature shifts and pharmacological perturbations. temperature shifts interfered with the regulation of tubulin synthesis. inhibition of dna synthesis prevents tubulin degradation after completion of the cell cycle (ducommun and wright, eur. j. cell biol., 50:48-55, 1989) but did not perturb the initiation of tubulin syn ...19902145291
identification of a second retrotransposon-related element in the genome of physarum polycephalum.the repetitive fraction of the genome of the eukaryotic slime mould physarum polycephalum is dominated by tp1, a family of retrotransposon-like sequences. tp1 elements are arranged in scrambled clusters probably arising from integration of the element into copies of its own sequence. the present report describes a second sequence family, tp2, which has been identified within cloned dna segments of scrambled tp1 sequences. like tp1, the tp2 element is structurally related to retrotransposons, hav ...19902162742
structure-function analysis of mononucleotides and short oligonucleotides in the priming of enzymatic dna synthesis.the reversed-phase chromatography technique was employed in the measurement of dna synthesis at the primers d(pt)n, r(pu)n, d(pa)n, and r(pa)n (n = 1-16) in the presence of template poly(da) or poly(dt). dna synthesis was catalyzed by escherichia coli dna polymerase i klenow fragment, physarum polycephalum dna polymerase beta-like, p. polycephalum dna polymerase alpha, and human placenta dna polymerase alpha. values of km and vmax were measured as functions of the primer chain lengths. it was fo ...19902182118
control of actin filament length by phosphorylation of fragmin-actin complex.fragmin is a ca2(+)-sensitive f-actin-severing protein purified from a slime mold, physarum polycephalum (hasegawa, t., s. takahashi, h. hayashi, and s. hatano. 1980. biochemistry. 19:2677-2683). it binds to g-actin to form a 1:1 fragmin/actin complex in the presence of micromolar free ca2+. the complex nucleates actin polymerization and caps the barbed end of the short f-actin (sugino, h., and s. hatano. 1982. cell motil. 2:457-470). subsequent removal of ca2+, however, hardly dissociates the c ...19902202733
primary structure of profilins from two species of echinoidea and physarum polycephalum.profilin is a small g-actin-binding protein, the amino acid sequence of which was previously reported for calf, human, acanthamoeba and yeast. here the amino acid sequences of three profilins obtained from eggs of two species of echinoidea, clypeaster japonicus (order, clypeasteroida) and anthocidaris crassispina (order, echinoida), and plasmodium of physarum polycephalum were determined. two echinoid profilins were composed of 139 amino acid residues, n-termini were acylated and the molecular m ...19902209623
a plasmodial specific mrna (plasmin c) from physarum polycephalum encodes a small hydrophobic cysteine-rich protein. 19902216739
variable pathways for developmental changes in composition and organization of microtubules in physarum polycephalum.the development of uninucleate amoebae into multinucleate plasmodia in myxomycetes is called the amoebal-plasmodial transition (apt). during the apt in physarum polycephalum the ability to form flagellar axonemes is lost; the astral, open mitosis is replaced by the anastral, closed mitosis; and cytoskeletal microtubules disappear. these changes are accompanied by alterations in the repertoire of expressed tubulins. using immunofluorescence microscopy we have studied the timing of loss and accumu ...19902229192
purification and characterization of a novel intracellular acid proteinase from the plasmodia of a true slime mold, physarum polycephalum.an acid proteinase was purified to apparent homogeneity from the plasmodia of a slime mold, physarum polycephalum, by a combination of detergent extraction, acid precipitation, and column chromatographies on deae-sephadex, hydroxylapatite, cm-sephadex, and sephadex g-100. the enzyme was shown to be composed of two polypeptide chains (a 31-kda heavy chain and a 23-kda light chain) cross-linked by disulfide bond(s). the nh2-terminal amino acid sequence of the heavy chain was determined to be ala-g ...19902246266
a purified cellular extract accelerates the cell cycle in physarum polycephalum.plasmodia of the myxomycete physarum polycephalum (strain cl) were collected at different times during the cell cycle and extracts were prepared from homogenates using a buffer optimized for microinjection into plasmodial veins. these extracts were injected into plasmodia during the first 3 h of the cell cycle. the time of the following mitosis was monitored and compared with that of the buffer-injected controls. extracts of plasmodia homogenized 45 min before late telophase accelerated the onse ...19902257887
changes in phospholipid composition and phospholipase d activity during the differentiation of physarum polycephalum.changes in phospholipid composition and phospholipase d activity were observed during a differentiation from haploid myxoamoebae to diploid plasmodia of a true slime mold, physarum polycephalum. in the amoeboid stage, the main components of phospholipid fraction were phosphatidylethanolamine (pe, 43.3%), phosphatidylcholine (pc, 28.8%) and phosphatidylinositol (pi, 8.0%), but in the plasmodial stage, pc was dominant (40.7%) and other main components were pe (31.5%) and phosphatidic acid (pa, 11. ...19902317522
dynamic organization of atp and birefringent fibrils during free locomotion and galvanotaxis in the plasmodium of physarum polycephalum.directed migration by a cell is a good phenomenon for studying intracellular coordination. dynamic organization of both atp and birefringent fibrils throughout the cell was studied in the multinuclear ameboid cell of the physarum plasmodium during free locomotion and galvanotaxis. in a directionally migrating plasmodium, waves of atp as well as thickness oscillations propagated from just inside the advancing front to the rear, and atp concentration was high at the front on the average. in a dc e ...19902324194
mitochondrial dna of physarum polycephalum: physical mapping, cloning and transcription mapping.mitochondrial dna (mtdna) has been isolated from four strains of physarum polycephalum and a restriction site map has been determined using nine restriction enzymes. the restriction site maps of the four strains are similar but each strain is distinguished by insertions, deletions and restriction enzyme site polymorphisms. the sum of the restriction fragments gives mitochondrial genome sizes which vary from about 56 kb to 62 kb. in all four strains the composite map of the restriction enzyme sit ...19902340593
characterization of i-ppo, an intron-encoded endonuclease that mediates homing of a group i intron in the ribosomal dna of physarum polycephalum.a novel and only recently recognized class of enzymes is composed of the site-specific endonucleases encoded by some group i introns. we have characterized several aspects of i-ppo, the endonuclease that mediates the mobility of intron 3 in the ribosomal dna of physarum polycephalum. this intron is unique among mobile group i introns in that it is located in nuclear dna. we found that i-ppo is encoded by an open reading frame in the 5' half of intron 3, upstream of the sequences required for sel ...19902355911
cell-specific expression of a profilin gene family.profilin is a ubiquitous eukaryotic protein that inhibits actin polymerization. we cloned and sequenced the two profilin genes from the acellular slime mold physarum polycephalum. the genes, proa and prop, each contain two introns. primer extension experiments showed two possible transcription start sites in the profilin a gene and one start site in the profilin p gene. the profilin a mrna has two polyadenylation sites, which yield mrnas of about 600 and 500 nucleotides. the profilin p mrna has ...19902372376
cellular events during sexual development from amoeba to plasmodium in the slime mould physarum polycephalum.time-lapse cinematography and immunofluorescence microscopy were used to study cellular events during amoebal fusions and sexual plasmodium development in physarum polycephalum. amoebal fusions occurred frequently in mixtures of strains heteroallelic or homoallelic for the mating-type locus mata, but plasmodia developed only in the mata-heteroallelic cultures. these observations confirmed that mata controls development of fusion cells rather than cell fusion. analysis of cell pedigrees showed th ...19902398347
isolation and characterization of a membrane-dna complex in the mitochondria of physarum polycephalum.a membrane-dna complex was isolated by centrifugation of sheared lysate of isolated mitochondria in 20-60% sucrose step solution. analyses using hoechst 33258/cscl density gradient centrifugation and restriction endonuclease treatment showed that dna in the membrane-dna complex was at-rich compared with total mitochondrial dna (mt dna) and contained eco ri fragments of e-4, 5 and 8, which were localized on the right hand of physarum mitochondrial genome. phenethyl alcohol (pea) and ethidium brom ...19852415374
analysis of physarum proteins throughout the cell cycle by two-dimensional page.the accumulation of several hundred proteins during the nuclear division cycle of physarum polycephalum was measured by digital image processing of silver-stained two-dimensional (2d) polyacrylamide gels. in contrast to previous studies, we have used an organism with a naturally synchronous cell cycle, so there are no uncertainties concerning synchronization artifacts or cell-sorting artifacts, and we have measured the specific amounts of each protein rather than the rate of synthesis. since one ...19852415376
characterization of the nucleolar protein, b-36, using monoclonal antibodies.a panel of nine monoclonal antibodies has been produced against a major nuclear protein, b-36, purified from the slime mold physarum polycephalum. b-36, a 34 kd protein biochemically similar to the major structural proteins of mammalian hnrnp particles, was previously shown to be largely associated with the nucleolus. eight of the monoclonal antibodies are specific for b-36 protein in physarum and at least three different epitopes are represented among these eight. using the monoclonal antibodie ...19862427347
methylation is an early and necessary step in the sporulation programme of the slime mold physarum polycephalum.formation of sporangia can be induced in starved macroplasmodia of physarum polycephalum by illumination. this process of morphogenesis which starts 9 h after the needed period of illumination can be prevented by the competitive inhibitors of methyltransferases s-adenosyl-homocysteine or l-ethionine, applied either directly by microinjection into the plasmodia or by addition to the medium. because 5-azacytidine (aza-c) or 5-aza-2'-deoxycytidine (aza-dc) also prevent sporulation (in contrast to c ...19862428647
two monoclonal antibodies to actin: one muscle selective and one generally reactive.two igg1, kappa monoclonal antibodies (mab) against actin have been obtained from a fusion in which chicken gizzard actin was used as the immunogen. one mab, designated b4, shows a preferential reactivity toward enteric smooth muscle actin but also cross-reacts with skeletal, cardiac, and aorta actins on the basis of immunoblots, elisa assays, and indirect immunofluorescence. however, this antibody does not react with either cytoplasmic actin in any of these assay systems. a second mab, designat ...19882460261
photomorphogenesis in physarum polycephalum. temporal expression pattern of actin, alpha- and beta-tubulin.photo-induced fruiting-body formation of the slime mold physarum polycephalum can be divided into two stages. the first stage (i) starts with the beginning of illumination (0 h) and ends with the formation of nodules (12 h). the second stage (ii) is characterized by culmination, sporangiophore formation and melanization of sporangiophore heads (13-17 h). we investigated the expression of actin, alpha- and beta-tubulin during this differentiation process using northern blot analysis and run-off t ...19892465146
transcriptionally active chromatin can be selectively released by dnase i from physarum polycephalum genome.in a simple eukaryote physarum polycephalum about 13% of the genome is transcribed into abundant cytoplasmic rna as shown by s1 nuclease digestion of dna-rna hybrids. mild digestion of isolated physarum nuclei with dnase i liberates a fraction of chromatin 3.5-fold enriched in sequences hybridizing by physarum poly(a)+ rna. this fraction is similarly enriched in histone h4 and actin genes known to be actively transcribed in physarum. high content (about 45%) of actively transcribed sequences in ...19882469274
recognition of specific physarum alpha-tubulin isotypes by a monoclonal antibody. sequence heterogeneity around the acetylation site at lysine 40.the monoclonal antibody 6-11b-1 recognises specifically the acetylated form of alpha-tubulin. the acetylation event occurs on a unique lysine residue, lysine 40. using 6-11b-1, acetylated alpha-tubulin was detected in myxamoebae but not plasmodia of physarum polycephalum. following chemical acetylation plasmodial alpha-tubulin was detected by 6-11b-1. the monoclonal antibody kmp-1 recognises certain physarum alpha-tubulin isotypes but only in non-acetylated form. whilst recognising all the non-a ...19892479555
histone genes in physarum polycephalum: transcription and analysis of the flanking regions of the two h4 genes.the histone h4 multigene family of physarum polycephalum consists of two genes, h41 and h42. both genes have an unusual structure in that they are interrupted by a small intron. the structure of the p. polycephalum h4 genes is discussed and compared to the structure of histone genes of other organisms. s1 nuclease analysis was used to map the 5' and 3' ends of the histone h4 messengers. we show that the histone h4 genes have a hybrid structure; they are interrupted by an intervening sequence, as ...19892499687
regulation of mitosis onset and thymidine kinase activity during the cell cycle of physarum polycephalum plasmodia: effect of fluorodeoxyuridine.the effects of fluorodeoxyuridine were investigated during three events of the cell cycle: s-phase, mitosis, and the cyclic synthesis of thymidine kinase in the synchronous plasmodium of the myxomycete physarum. dna synthesis was inhibited, and there was limited action on other macromolecular syntheses. when dna synthesis was slowed down, onset of the following increase of thymidine kinase synthesis occurred at approximately the same time as in the control, but mitosis was blocked in a very earl ...19892523892
expression of udp-glucose: poriferasterol glucosyltransferase in the process of differentiation of a true slime mold, physarum polycephalum.an expression of udp-glucose:poriferasterol glucosyltransferase activity associated with differentiation of a true slime mold, physarum polycephalum, from haploid myxoamoebae to diploid plasmodia was demonstrated. in the haploid cells, this enzyme activity was not detected, but after conjugation of the myxoamoebae, the enzyme activity was expressed and increased definitely. in the plasmodial stage, high enzyme activity was maintained constantly. the enzyme was partially purified (35-fold purific ...19892528379
variation of tubulin half-life during the cell cycle in the synchronous plasmodia of physarum polycephalum.the half-life of tubulin has been studied during the cell cycle of the myxomycete physarum, using a specific quantitative immunological method. in asynchronous microplasmodial and amoebal cultures the apparent half-life of tubulin was greater than 15 h. in contrast, in the naturally synchronous plasmodia, in which tubulin exhibits a cyclic synthesis, we have shown for the first time that tubulin half-life was not constant through the cell cycle. there was no tubulin degradation before mitosis, w ...19892533071
a mobile group i intron in the nuclear rdna of physarum polycephalum.we have shown that a strain-specific group i intron (intron 3) in the nuclear extrachromosomal rdna or physarum polycephalum is a mobile element. shortly after mating of amoebae from intron-lacking and intron-containing strains, intron 3 transposes in a site-specific manner into all available recipient molecules. the transposition appears to occur by gene conversion, as evidence by the co-conversion of adjacent sequences and by double strand breakage observed in some of the recipient rdna molecu ...19892536594
a fragmin-like protein from plasmodium of physarum polycephalum that severs f-actin and caps the barbed end of f-actin in a ca2+-sensitive way.many protein factors regulating actin polymerization can be extracted from plasmodia of physarum polycephalum in the presence of a high egta concentration (30 mm). a protein factor with the molecular weight of 60,000 (60 kda protein) was especially interesting because of its fragmin-like properties. we purified and characterized this 60 kda protein in the present study. the purified 60 kda protein enhanced the initial rate of g-actin polymerization, severed f-actin, and capped the barbed end of ...19892553683
a new snrna with a trimethylated cap structure in the slime mold physarum polycephalum. 19892587264
the effects of tunicamycin, mevinolin and mevalonic acid on hmg-coa reductase activity and nuclear division in the myxomycete physarum polycephalum.the effects of two inhibitors of 3-hydroxy 3-methyl glutaryl-coenzyme a reductase (tunicamycin and mevinolin) on nuclear division in the myxomycete physarum polycephalum were examined. tunicamycin exerted a minor effect on division in synchronized cultures, whereas mevinolin delayed the second, third and fourth nuclear divisions with increasing efficiency. mevinolin also appeared to be the more potent inhibitor of hmg-coa reductase, which catalyses the rate-limiting step in the biosynthesis of c ...19892592440
the nucleotide sequence of a developmentally regulated cdna from physarum polycephalum. 19892602164
location of a single beta-tubulin gene product in both cytoskeletal and mitotic-spindle microtubules in physarum polycephalum.in the mutant ben210 of physarum polycephalum several beta-tubulins are detectable. beta 1-tubulin is unique to the myxamoeba, beta 2-tubulin is unique to the plasmodium, and the mutant beta 1-210 tubulin encoded by the bend210 allele is present in both cell types. in order to analyse the subcellular distribution of the beta 1-210 polypeptide, we prepared cytoskeletons from myxamoebae and mitotic spindles from plasmodia, and examined the tubulin polypeptide composition of these microtubular orga ...19892621444
direct repeats at nuclear matrix-associated dna regions and their putative control function in the replicating eukaryotic genome.short dna regions, known to contain replication origins, were isolated from 2 m nacl resistant nuclear structures of physarum polycephalum after predigestion with dnase. regions of 100 bp average length were cloned and sequenced. about 25% of the clones contained direct repeats of 12 to 16 bp and variable base sequences, that have been shown to possess the potential of playing a crucial role in the control of dna replication. in one of the two alternative three-dimensional configurations such re ...19892627800
purification of tropomyosin from saccharomyces cerevisiae and identification of related proteins in schizosaccharomyces and physarum.tropomyosin is a key component of the contractile systems found in muscle and nonmuscle cells of higher eukaryotes. based on properties common to all tropomyosins, we have purified a protein from saccharomyces cerevisiae that resembles tropomyosins from higher cells. the yeast protein remains soluble after heat treatment at 90 degrees c, has an apparent polypeptide molecular weight of 33,000, an isoelectric point of 4.5, a stokes radius of 3.5 nm, and a sedimentation coefficient of 2.6 s. it bin ...19892643110
studies of histidine phosphorylation by a nuclear protein histidine kinase show that histidine-75 in histone h4 is masked in nucleosome core particles and in chromatin.histone h4 is a good substrate in vitro for the protein histidine kinase activity found both in physarum polycephalum nuclear extracts and in saccharomyces cerevisiae cell extracts. however, histone h4 in nucleosome core particles is not a substrate for these kinases. isolated chromatin was also not a substrate for the protein histidine kinase. the results significantly limit possible interpretations of histidine phosphorylation on histone h4 in vivo and provide a new, sharper focus for future w ...19892643923
structure and expression of an alpha-tubulin gene of physarum polycephalum.fragments of physarum polycephalum dna generated by partial digestion with sau3a were cloned into phage-lambda embl4. a recombinant (phage-lambda e alpha tu) containing an alpha-tubulin (e alpha-tubulin) gene was isolated. the e alpha-tubulin gene is part of the alt b locus. the gene was sequenced and was found to contain seven intervening sequences. the alpha-tubulin isotype (e alpha-tubulin) encoded by the gene has a methionine residue at the c-terminus. the e alpha-tubulin gene has much in co ...19892659344
evidence for a homolog of the yeast cell cycle regulatory gene product of cdc2+ in physarum polycephalum.evidence for the presence of a cdc2-like protein in physarum polycephalum has been obtained using a peptide antibody directed against a highly conserved amino acid sequence near the n-terminal end of cdc2, cdc28 and cdc2hs. the antibody detected a 34 kda cytoplasmic protein, similar in apparent size to cdc2 in yeast and cdc2hs in hela cells. a 60 kda nuclear band was also detected in physarum but not in yeast or hela. evidence is presented that this is not related to the 34 kda protein nor is it ...19892663500
incorporation of tubulin from an evolutionarily diverse source, physarum polycephalum, into the microtubules of a mammalian cell.physarum myxamoebal tubulin was injected into ptk2 cells to determine whether tubulin from this eukaryotic microbe could act as a reporter for microtubule growth and dynamics in a mammalian cell. the distribution of physarum tubulin was determined by the use of a monoclonal antibody specific for physarum tubulin and unable to detect mammalian tubulin. physarum tubulin was incorporated into the microtubules of both interphase arrays and the mitotic spindle. measurements of microtubule turnover ki ...19892689461
the localization of the divergent beta 2-tubulin isotype in the microtubular arrays of physarum polycephalum.the beta 2-tubulin isotype of physarum polycephalum is only 83% identical in amino acid sequence with the constitutively expressed beta 1b-tubulin and the myxamoeba-specific beta 1a-tubulin isotypes. a polyclonal antibody specific for beta 2-tubulin was used to monitor the subcellular distribution of the beta 2-tubulin antigen in the mitotic spindle of the mature plasmodium - the sole microtubular array in that stage of physarum. by immunofluorescence, the beta 2-tubulin antigen was detected thr ...19892695530
evidence for active interactions between microfilaments and microtubules in myxomycete flagellates.we have previously observed the apparent displacement of microfilaments over microtubules in the backbone structure of permeabilized flagellates of physarum polycephalum upon addition of atp (uyeda, t. q. p., and m. furuya. 1987. protoplasma. 140:190-192). we now report that disrupting the microtubular cytoskeleton by treatment with 0.2 mm ca2+ for 3-30 s inhibits the movement of the microfilaments induced by subsequent treatment with 1 mm mg-atp and 10 mm egta. stabilization of microtubules by ...19892715175
immunoelectron microscopic localization of the nucleolar protein b-36 (fibrillarin) during the cell cycle of physarum polycephalum.monoclonal antibodies raised against the 34-kd nucleolar protein, b-36, from the slime mold physarum polycephalum have been used to examine the electron microscopic localization of b-36 during the cell cycle in physarum. during interphase, b-36 is found primarily in regions corresponding to the dense fibrillar component. this is similar to what has been observed for the putative mammalian homologue of b-36, fibrillarin. during mitosis, b-36 remains associated with perichromosomal nucleolar remna ...19892736327
biological oxidation and the mobilization of mitochondrial calcium during the differentiation of physarum polycephalum.we have previously reported that calcium is required for the starvation-induced differentiation of the slime mold, physarum polycephalum. with the exception of calcium, each component of the complex starvation medium may be withheld and the organism will still differentiate into spherules. the results of the present study reveal that spherulation will proceed normally when the microplasmoidal cells are transferred from nutrient medium to a citrate buffer containing only 8 mm cacl2. electron micr ...19892745566
changes in activity and subcellular localization of alpha-like dna polymerase during cell cycle of physarum polycephalum.regulation of dna replication was given attention by examining the subcellular localization of alpha-like dna polymerase in physarum polycephalum. the activity per plasmodium increased by 2-fold in the cytoplasm during the g2-phase, and decreased with a concomitant increase in nuclei prior to dna replication. this would suggest that the enzyme translocates from the cytoplasm to the nucleus, co-ordinately with dna replication. in nuclei, the nuclear matrix-bound activity increased during the s-ph ...19892764963
an unusual polyanion from physarum polycephalum that inhibits homologous dna polymerase alpha in vitro.from extracts of microplasmodia of physarum polycephalum and their culture medium, an unusual substance was isolated which inhibited homologous dna polymerase alpha of this slime mold but not beta-like dna polymerase and not heterologous dna polymerases. analysis, especially nmr spectroscopy, revealed the major component to be an anionic polyester of l-malic acid and the inhibition to be due to poly(l-malate) in binding reversibly to dna polymerase alpha. the mode of inhibition is competitive wi ...19892765532
coordinate replication of dispersed repetitive sequences in physarum polycephalum.the synchronous macroplasmodial growth phase of the slime mould physarum polycephalum was used to study the in vivo replication of large chromosomal dna segments. newly replicated dna was isolated at various points in s-phase by its preferential association with the nuclear matrix. this dna was then used to probe cosmid clones of the physarum genome. the results indicate that certain dispersed repetitive sequences in the genome are coordinately replicated. the observed pattern of replication may ...19892784387
selective initiation of replication at origin sequences of the rdna molecule of physarum polycephalum using synchronous plasmodial extracts.a cell-free system using synchronous plasmodial extracts initiates replication selectively on the 60 kb rdna palindrome of physarum polycephalum. preferential labeling of rdna fragments by nuclear extracts, in which elongation is limited, indicates that initiation occurs at two positions corresponding to in vivo origins of replication estimated by electron microscopy. both nuclear and whole plasmodial extracts initiate selectively within a plasmid, pphr21, containing one of these origins. in thi ...19892813064
nuclear polyphosphate as a possible source of energy during the sporulation of physarum polycephalum.31p nmr spectroscopic analysis of the polyphosphate pool in cellular and nuclear extracts of physarum polycephalum demonstrates that plasmodia and cysts contain inorganic polyphosphates with an average chain length of about 100 phosphates. however, only during sporulation are these high-molecular-weight polyphosphates degraded to a lower molecular weight corresponding to an average chain length of about 10 phosphates. since polyphosphates are degraded even in the presence of a sufficiently large ...19892817896
developmental regulation and identification of an isotype encoded by altb, an alpha-tubulin locus in physarum polycephalum.a subcloned portion of the 5' nontranslated sequence from a physarum alpha-tubulin cdna is specific for a single alpha-tubulin locus, altb, of physarum polycephalum. we find that this locus is expressed only in the plasmodium and encodes at least an alpha 1-tubulin isotype, which we have designated alpha 1b. hybridization patterns of other subclones of this cdna reveal two sequences for alpha-tubulin at the altb locus.19872823127
gene families encode the major encystment-specific proteins of physarum polycephalum plasmodia.the encystment of physarum polycephalum plasmodia, also called spherulation, involves the synthesis of many specific mrnas and proteins. most of these molecules accumulate at the onset of the major morphological and physiological changes typical of this differentiation pathway and are not present during the other two transitions leading to dormancy in physarum, namely sporulation and encystment of amoebae. the nucleotide sequences of apparently full-length cdna copies of the four major encystmen ...19872830170
the f-actin capping proteins of physarum polycephalum: cap42(a) is very similar, if not identical, to fragmin and is structurally and functionally very homologous to gelsolin; cap42(b) is physarum actin.we have carried out a primary structure analysis of the f-actin capping proteins of physarum polycephalum. cap42(b) was completely sequenced and was found to be identical with physarum actin. approximately 88% of the sequence of cap42(a) was determined. cap42(a) and fragmin were found to be identical by amino acid composition, isoelectric point, mol. wt, elution time on reversed-phase chromatography and amino acid sequence of their tryptic peptides. the available sequence of cap42(a) is greater ...19872832154
polymorphism and uniparental inheritance of mitochondrial dna in physarum polycephalum.restriction endonuclease analysis was done on mitochondrial dna (mtdna) from 19 plasmodial strains of physarum polycephalum. the extent of mtdna variation among these strains was high in comparison with other organisms, and provides a useful source of cytoplasmic genetic markers. the strains were classified into seven groups according to their mtdna types. although plasmodia of p. polycephalum are diploid, formed by fusion of amoebal isogametes, each of the 19 plasmodia possessed mtdna of only a ...19872833563
a gene encoding the major beta tubulin of the mitotic spindle in physarum polycephalum plasmodia.the multinucleate plasmodium of physarum polycephalum is unusual among eucaryotic cells in that it uses tubulins only in mitotic-spindle microtubules; cytoskeletal, flagellar, and centriolar microtubules are absent in this cell type. we have identified a beta-tubulin cdna clone, beta 105, which is shown to correspond to the transcript of the betc beta-tubulin locus and to encode beta 2 tubulin, the beta tubulin expressed specifically in the plasmodium and used exclusively in the mitotic spindle. ...19882835667
purification of myxamoebal fragmin, and switching of myxamoebal fragmin to plasmodial fragmin during differentiation of physarum polycephalum.we have isolated and purified an activity from amoebae of physarum polycephalum that reduces the flow birefringence of a solution of f-actin in a ca2+-dependent manner. the purified activity from 100 g of amoebae consisted of 1 mg of a 40,000 mol. wt protein. dnase i-affinity chromatography demonstrated that the protein binds to physarum actin in a ca2+-dependent manner, and the binding is not reversed by excess egta. viscometric measurement indicated that the protein (i) accelerates polymerizat ...19882842375
nucleotide sequence of pig plasma gelsolin. comparison of protein sequence with human gelsolin and other actin-severing proteins shows strong homologies and evidence for large internal repeats.pig plasma gelsolin (mr = 81595; 739 residues) contains 704 identical residues out of a maximum 730 when compared to the cytoplasmic form of human gelsolin. the cdna sequence also codes for a peptide of 33 residues n-terminal to the nine-residue plasma extension sequence previously reported: these 33 residues are highly homologous to the human signal peptide and plasma extension. comparison of the gelsolin sequences with chicken brush border villin, severin from dictyostelium discoideum and frag ...19882850369
centriole size modifications during the cell cycle of the amoebae of the mxyomycete physarum polycephalum.anterior and posterior centrioles of physarum amoebae are indistinguishable by their size during interphase but there is a correlation between the size of the two centrioles in the same amoeba. the interphase length of centrioles in diploid amoebae possessing only one pair of centrioles was 11% longer than in the case of the haploid strain. treatment with taxol led to a 23 and 32% increase of the mean length in interphase and blocked mitosis, respectively. conversely, during control mitosis the ...19852868129
differential expression of an alpha-tubulin gene during the development of physarum polycephalum.the expression of an alpha-tubulin gene (altb1 (n alpha tu) [(1987) j. mol. biol. 193, 427-438]) of physarum polycephalum (strain cldaxe) was found to be governed by a developmental switch since mrna transcripts were detected, by s1 nuclease analysis, in the plasmodial but not the amoebal phase of the life-cycle. the conclusion that the altb1 (n alpha tu) allele codes for a plasmodial specific alpha-tubulin isotype is supported by recent amino acid sequence data.19872885221
replication timing of 10 developmentally regulated genes in physarum polycephalum.we have tested the hypothesis which stipulates that only early-replicating genes are capable of expression. within one cell type of physarum - the plasmodium - we defined the temporal order of replication of 10 genes which were known to be variably expressed in 4 different developmental stages of the physarum life cycle. southern analysis of density-labeled, bromodesoxyuridine-substituted dna reveals that 4 genes presumably inactive within the plasmodium, were not restricted to any temporal comp ...19892915922
changes in diadenosine tetraphosphate levels in physarum polycephalum with different oxygen concentrations.cellular levels of diadenosine tetraphosphate (ap4a) were measured, by a specific high-pressure liquid chromatography method, in microplasmodia of physarum polycephalum subjected to different degrees of hypoxia, hyperoxia, and treatment with h2o2. ap4a levels increased three- to sevenfold under anaerobic conditions, and the microplasmodia remained viable after such treatment. elevated levels of ap4a returned to the basal level within 5 to 10 min upon reoxygenation of the microplasmodia. the incr ...19892921243
a structural analysis of p. polycephalum u1 rna at the rna and gene levels. are there differentially expressed u1 rna genes in p. polycephalum? u1 rna evolution.u1 rnas were isolated from p. polycephalum microplasmodia nuclei and sequenced. a p. polycephalum gene coding for u1 rna was also isolated. the coding region of this gene differs at 3 positions compared to the isolated u1 rna species. both isolated rnas and the gene encoded rna can be folded according to the secondary structure model previously proposed for u1 rna. putative regulatory elements very similar to those required for efficient transcription of u rna genes from vertebrates, in particul ...19892922259
microtubule-associated protein-2 stimulates dna synthesis catalyzed by the nuclear matrix.microtubule-associated protein-2 (map-2) isolated from porcine brains stimulated dna synthesis catalyzed by the nuclear matrix isolated from physarum polycephalum in the presence of activated dna as exogenous templates. the degree of the stimulation depended on the amount of the nuclear matrix, but not on that of the template. map-2 also stimulated dna polymerase alpha activity solubilized from nuclei, but not dna polymerase beta activity. these results suggest that map-2 stimulates dna synthesi ...19892930545
dna synthesis by the isolated nuclear matrix from synchronized plasmodia of physarum polycephalum.nuclear matrices were isolated from plasmodia of a true slime mold, physarum polycephalum, and the dna synthetic activity in vitro was examined. these matrices isolated in s-phase catalyzed dna synthesis requiring mg2+, deoxyribonucleoside 5'-triphosphates and atp, without exogenous templates. the activity changed during s-phase with the rate of in vivo dna replication. product analysis by gel electrophoresis revealed that the matrices produced okazaki fragments. these results suggest that dna s ...19892930774
developmentally regulated late mrnas in the encystment of physarum polycephalum plasmodia.physarum polycephalum plasmodia survive adverse conditions by transforming into encysted cells called spherules. in this work we analysed the developmentally regulated mrnas from the late stages of spherulation. a cdna library was constructed and four abundant mrnas were identified. one of the mrnas was present in trace amounts in early spherules, while the other three were found only in late spherules. a cdna clone for one of the late spherulation specific mrnas was sequenced. it codes for a 33 ...19892930775
the inhibitory ca2+-regulation of the actin-activated mg-atpase activity of myosin from physarum polycephalum plasmodia.myosin was rapidly prepared from the slime mould, physarum polycephalum to a high level of homogeneity (greater than 95%), in a high yield (about 10 mg/100 g tissue) and in a phosphorylated state (about 5 mol phosphate/mol of 500,000 mr myosin). actin activated the mg-atpase activity of this myosin in the absence of ca2+ about 30-fold, and this actin-activated atpase activity was reduced to about 20% of the original activity when ca2+ concentration was increased to 50 microm, i.e., the actin-myo ...19862940236
isolation and characterization of myosin from amoebae of physarum polycephalum.myosin was isolated from amoebae of physarum polycephalum and compared with myosin from plasmodia, another motile stage in the physarum life cycle. amoebal myosin contained heavy chains (mr approximately 220,000), phosphorylatable light chains (mr 18,000), and ca2+-binding light chains (mr 14,000) and possessed a two-headed long-tailed shape in electron micrographs after rotary shadow casting. in the presence of high salt concentrations, myosin atpase activity increased in the following order: m ...19862940248
structure of physarum actin gene locus arda: a nonpalindromic sequence causes inviability of phage lambda and reca-independent deletions.previously we reported that approx. 80% of the genome from the plasmodial slime mold physarum polycephalum, including all the actin genes, can be cloned only in recbc- sbcb- escherichia coli hosts [nader et al., proc. natl. acad. sci. usa 82 (1985) 2698-2702]. we have now sequenced the actin gene locus arda. the nucleotide sequence of its coding region is flanked by the typical putative regulatory sequences for transcription initiation and polyadenylation. the coding region is interrupted by fiv ...19862951301
ornithine decarboxylase from neurospora crassa. purification, characterization, and regulation by inactivation.ornithine decarboxylase, a highly regulated enzyme of the polyamine pathway, was purified 670-fold from mycelia of neurospora crassa that were highly augmented for enzyme activity. the enzyme is significantly different from those reported from three other lower eucaryotic organisms: saccharomyces cerevisiae, physarum polycephalum, and tetrahymena pyriformis. instead, the enzyme closely resembles the enzymes from mammals. the mr = 110,000 enzyme is a dimer of 53,000 da subunits, with a specific a ...19872953728
a library of trimethylguanosine-capped small rnas in physarum polycephalum.we have constructed a cdna library for the trimethylguanosine-capped small rnas (srnas) in the acellular slime mold physarum polycephalum. capped srnas were purified from total cellular rna of vegetative microplasmodia by preparative immunoprecipitation with anti-trimethylguanosine antibody. the purified rna was analyzed by polyacrylamide gel electrophoresis. approx. eleven different capped srnas were observed with a size range of 70-204 nucleotides (nt). based on their approximate sizes, the pr ...19872956157
specific nuclear elimination in polyploid plasmodia of the slime mold physarum polycephalum.in growing plasmodia of the myxomycete physarum polycephalum (g2-phase), three distinct classes of nuclei with a relative dna content of 1x, 2x, and 4x are observed in the presumed haploid strain cl. the 2x and 4x species comprise up to 35% and 5% of the nuclei. quantitative cytofluorometric studies of nuclei isolated in either g2- or s-phase or after fudr treatment (g1 arrest) show that the three nuclear populations undergo a synchronous mitotic cycle and that the relative dna content of the nu ...19882967750
cell-cycle-specific activity of cyclic nucleotide phosphodiesterase in physarum polycephalum.the cell-cycle-related activities of the camp- and cgmp-dependent phosphodiesterases of physarum polycephalum were assayed. the activities of plasmodial homogenate and of selected subcellular fractions were measured. the results suggested the presence of both camp- and cgmp-dependent phosphodiesterase in the isolated nuclei of p. polycephalum. in addition, they reveal that the camp- and cgmp-dependent phosphodiesterase activities of the subcellular fractions fluctuate throughout the cell cycle. ...19852982493
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