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studies on ribonucleases from physarum polycephalum. purification and characterization of substrate specificity. 19695817396
studies on two nucleases and a ribonuclease from physarum polycephalum. purification and mode of action. 19695817397
growth of physarum flavicomum and physarum rigidum in chemically defined minimal media.physarum flavicomum, p. polycephalum, and p. rigidum grew at ph 4.2 in a medium composed of mineral salts, glucose, biotin, thiamine, hematin, and four amino acids. important differences in ph tolerance were noted among the species. the minimal medium of p. flavicomum and p. polycephalum contained the amino acids methionine, glycine, and arginine, but valine was also required by p. rigidum. starting with an inoculum of about 0.3 mg of protein per 25 ml of minimal medium, p. flavicomum and p. pol ...19695817554
dna synthesis by isolated nuclei of physarum polycephalum. 19655866844
prophase-like chromosome condensation induced by actinomycin d in the slime mold, physarum polycephalum. 19645892727
the effect of actidione on mitosis in the slime mold physarum polycephalum.actidione, reportedly a specific inhibitor of protein synthesis, was found to reduce the incorporation of labeled amino acids into proteins of the slime mold physarum polycephalum without drastically inhibiting the incorporation of nucleic acid precursors into rna. this inhibitor was found to completely block the ensuing mitosis if it was added at any time between telophase and late prophase. plasmodia given actidione in late prophase (about the time of nucleolar dissolution) went on through tel ...19655894452
sedimentation patterns of pulse-labeled rna in the mitotic cycle of physarum polycephalum. 19665936958
electron microscopic observations on the slime mold physarum polycephalum with specific reference to fibrillar structures. 19665949522
synthesis of a cytoplasmic dna during the g2 interphase of physarum polycephalum. 19665949776
genetic analysis of actidione-resistant mutants in the myxomycete physarum polycephalum, schw. 19665949974
ribonucleic acid synthesis in vivo in the synchronously dividing physarum polycephalum studied by cell fractionation. 19665950242
ribonucleic acid synthesis in vitro in nuclei isolated from the synchronously dividing physarum polycephalum. 19665950243
anaphase delay after inhibition of protein synthesis between late prophase and prometaphase.the relationship between protein synthesis and mitosis was studied in physarum polycephalum, a plasmodial slime mold whose nuclear divisions are synchronous. results of studies with actidione (cycloheximide), an inhibitor of protein synthesis, indicated that the essential structural proteins for mitosis and nuclear reconstruction were completed prior to the dissolution of the nucleolus in prophase. proteins that determine the duration of the transition from metaphase to nuclear reconstruction we ...19665951133
methionine metabolism of the myxomycete physarum polycephalum.daniel, john w. (university of wisconsin, madison), and karlee babcock. methionine metabolism of the myxomycete physarum polycephalum. j. bacteriol. 92:1028-1035. 1966.-previous studies have shown that physarum polycephalum requires exogenous methionine for growth, but not cysteine, folic acid, or vitamin b(12). methionine can also serve as the sole source of sulfur for all cellular requirements, without limiting the growth rate. s-methyl-l-cysteine, 2-hydroxy-4-methiol butyric acid, s-adenosyl- ...19665951320
occurrence and morphology of a fibrous body in the mitochondria of the slime mold physarum polycephalum. 19666007171
polysome patterns and protein synthesis during the mitotic cycle of physarum polycephalum. 19666007180
synchronization of mitosis by the fusion of the plasmodia of physarum polycephalum. 19666008374
nucleic acid synthesis during and after mitosis in the slime mold, physarum polycephalum. 19676067128
nearest neighbor frequencies and the phylogenetic origin of mitochondrial dna in physarum polycephalum. 19676067777
mitochondrial dna synthesis and the mitotic cycle in physarum polycephalum. 19676069137
preservation of physarum polycephalum plasmodia in liquid nitrogen. 19676069282
transcription of nuclear dna in nuclei isolated from plasmodia at different stages of the cell cycle of physarum polycephalum. 19676069892
dna synthesis by isolated mitochondria of physarum polycephalum. 19676070941
regions in the ribosomal minichromosome of physarum polycephalum are protected from restriction nucleases; protection is insensitive to high salt in the g phase and sensitive in the m phase of the cell cycle.in the central spacer region of the extrachromosomal ribosomal dna of the slime mold physarum polycephalum, four small regions of related sequence are completely inaccessible to restriction endonucleases (hinfi and mboi). in addition, some sequences neighboring the inaccessible ones, are partially inaccessible to restriction enzymes and micrococcal nuclease. taking advantage of the natural synchrony of physarum plasmodia, we found that this protection is present throughout the cell cycle. treatm ...19846094832
utilization of polyadenylate mrna during growth and starvation in physarum polycephalum.the effect of growth on the efficiency of utilization of poly(a)-containing mrna for translation has been investigated in microplasmodia of physarum polycephalum. measurement of the relative proportions of poly(a)-rich mrna in polysomal and post-polysomal fractions isolated by sucrose density gradient centrifugation reveals that newly synthesized poly(a)-rich mrna is present in increasing proportions in the polysomal region during exponential growth. however, the proportion of long-lived poly(a) ...19806108214
the effect of age on the properties of poly(a)-containing messenger rna in physarum polycephalum.the effect of ageing on the properties of polysomal poly(a)-containing messenger rna [poly(a)+ mrna] of physarum polycephalum has been investigated. using poly(u)--sepharose affinity chromatography it was shown that shortening of the poly(a) tract occurred as the age of the mrna population increased. analysis of the poly(a) segments by use of polyacrylamide gel electrophoresis, after digestion of polysomal poly(a)+ mrna molecules with rnaase a and rnaase t1, revealed that their lengths ranged fr ...19816119350
a novel 36,000-dalton actin-binding protein purified from microfilaments in physarum plasmodia which aggregates actin filaments and blocks actin-myosin interaction.in the plasmodia of physarum polycephalum, which show a cyclic contraction-relaxation rhythm of the gel layer, huge aggregates of entangled actin microfilaments are formed at about the onset of the relaxation (r. nagai, y. yoshimoto, and n. kamiya. 1978. j. cell sci. 33:205-225). by treating the plasmodia with triton x-100, we prepared a demembranated cytoskeleton consisting of entangled actin filaments and found that the actin filaments hardly interact with rabbit skeletal myosin. from the cyto ...19826126481
phy m: an rnase activity specific for u and a residues useful in rna sequence analysis.physarum polycephalum, an acellular slime mold, produces an endoribonuclease activity (phy m) useful in direct rna sequence determination. under conditions previously described for direct enzymatic rna sequencing (7m urea, 50 degrees c, ph 5.0)1 phy m cleaves almost exclusively and uniformly at up-n and ap-n. in the absence of urea up-n, ap-n, and gp-n are attacked in a sequence specific way identical to that found with rnase phy i2 digests performed under the same reaction conditions.19806160466
[regulation of various hydrolase activities in the myxomycete physarum polycephalum].in a standard growing medium, the specific activities of acid-phosphatase, beta-galactosidase and beta-glucosidase of physarum polycephalum increase during the growth of the culture. the decrease of the ph of the culture medium during the growth has no effect on the variations of these hydrolase activities. in a glucose-starved medium, the specific activity of beta-galactosidase increases up to 350% of its initial value in 24 h, whereas the specific activities of acid phosphatase and beta-glucos ...19806163404
characterisation of a microtubule organising centre from physarum polycephalum myxamoebae. 19816166755
cytoplasmic processing events in the polyadenylate region of physarum messenger rna.cytoplasmic processing events in the poly(a) region of mrna from physarum polycephalum are reviewed. two classes of poly-containing rna [poly(a)+ rna] exist in the cytoplasm. one contains very short poly(a) sequences, averaging about 15 adenylate residues, while the other contains relatively long poly(a) sequences, averaging about 60 residues. molecules with short poly(a) sequences are found exclusively in the polysomes while those with long poly(a) sequences are restricted to the free cytoplasm ...19816166854
cloning and characterization of ribosomal rna gene of physarum polycephalum.as a first step in studies on the structure and expression of rrna gene of physarum polycephalum, the cloning of the gene in escherichia coli with plasmid vector dnas was performed and 8 different kinds of clones containing 26s, 19s, and 5.85 rrna genes were obtained. using these cloned fragments, the location of these rrna genes was determined by the southern hybridization and s1 mapping method. cloning of rdna fragments made it possible to analyze the fine structure of the rdna.19816169708
nucleotide sequence of the ribosomal rna gene of physarum polycephalum: intron 2 and its flanking regions of the 26s rrna gene.the 26s ribosomal rna gene of physarum polycephalum is interrupted by two introns, and we have previously determined the sequence of one of them (intron 1) (nomiyama et al. proc.natl.acad.sci.usa 78, 1376-1380, 1981). in this study we sequenced the second intron (intron 2) of about 0.5 kb length and its flanking regions, and found that one nucleotide at each junction is identical in intron 1 and intron 2, though the junction regions share no other sequence homology. comparison of the flanking ex ...19816171776
stored messenger ribonucleoprotein particles in differentiated sclerotia of physarum polycephalum.starvation induces vegetative microplasmodia of physarum polycephalum to differentiate into translationally-dormant sclerotia. the existence and the biochemical nature of stored mrna in sclerotia is examined in this report. the sclerotia contain about 50% of the poly (a)-containing rna [poly(a)+rna] complement of microplasmodia as determined by [3h]-poly(u) hybridization. the sclerotial poly(a)+rna sequences are associated with proteins in a ribonucleoprotein complex [poly(a)+mrnp] which sedimen ...19816175547
membrane histochemistry of physarum polycephalum myxamoebae.myxamoebae of physarum polycephalum are the uninucleate, haploid stage of the organism. histochemical studies were undertaken to characterize intracellular and plasma membranes, and to provide a basis for assaying subcellular fractions for enrichment in plasma membranes. lead salts deposition techniques were employed for hydrolytic enzymes. alcian blue-ruthenium red, osmium tetroxide-potassium ferrocyanide, and phosphotungstic acid-chromic acid stains were evaluated for specificity for plasma me ...19826185561
polyamine-mediated protein phosphorylations: a possible target for intracellular polyamine action.polyamines are well-known ubiquitous components of living cells. although these polycations have been implicated in the regulation of major cellular functions such as dna, rna and protein synthesis occurring during cellular proliferation and/or differentiation processes, their mechanism of action at the molecular level has remained obscure. on the other hand, protein phosphorylation has emerged as a regulatory process of prime importance in cellular regulation. data have recently been presented ...19836190690
[identification of histone mrna and isolation of a dna fraction enriched with physarum polycephalum histone genes].the 7-14s poly a- rna isolated from the s-state polysomes of the macroplasmodium p. polycephalum reveals the properties of histone mrna. in the wheat germ cell-free system this rna is translated into the polypeptides with the same electrophoretic mobility as core histones of p. polycephalum. using centrifugation in a cscl density gradient with actinomycin d, a dna fraction was isolated which hybridizes with cdna synthesized at 7-14s poly a- rna by reverse transcription with random priming. the d ...19836191781
cytoplasmic actin patterns in physarum as revealed by nbd-phallacidin staining.fluorescently labeled phallacidin, a f-actin specific drug, was used to demonstrate the morphological variety in the cytoskeletal actin pattern of thin-spread plasmodia of the acellular slime mould physarum polycephalum. the patterns observed in phallacidin-stained specimens consisted of a polygonal network in the anterior region, and of longitudinal as well as helically twisted fibrils in plasmodial strands of the posterior region. these observations are in complete accordance with our recent r ...19836193894
cyclic nucleotide responses and radiation-induced mitotic delay in physarum polycephalum.the response of the plasmodial levels of cyclic amp and cyclic gmp in physarum polycephalum to several putative phosphodiesterase inhibitors and to ionizing radiation has been measured. isobutylmethylxanthine (2 mm) induces a rapid transient threefold elevation of cyclic amp alone, with maximum response in about 10 min and return to the base line in about 30 min. theophylline (2 mm) induces a rapid, sustained twofold elevation of cyclic gmp only. caffeine (2 mm) and ro-20-1724 (18 microm) both e ...19846198672
intranuclear localization of histone acetylation in physarum polycephalum and the structure of functionally active chromatin.based on studies of histone acetylation in vivo in physarum polycephalum, we present the following hypotheses: (1) transcription-specific histone acetylation on histones h3 and h4 is a localized process at the nuclear matrix; (2) histone acetylation in the s phase, which is specific for newly synthesized histones, occurs in an intranuclear nonlocalized process. these hypotheses can explain: (1) the histone specificity of histone acetylation that is dependent on the functional state of the chroma ...19836202412
tubulin proteins and rna during the myxamoeba-flagellate transformation of physarum polycephalum.physarum myxamoebae can be reversibly induced to become flagellates. physarum flagellates contain a new form of tubulin, alpha 3, that is not found in nonflagellated cells. evidence is presented that suggests that alpha 3 tubulin arises through posttranslational modification of a preexisting alpha tubulin. pulse-chase experiments showed that labeled alpha 3 tubulin could be detected when flagellates formed after a chase. rna was isolated from myxamoebae at different times after induction of flag ...19846208478
mitotic delay following inhibition by 5'-fluorodeoxyuridine of s-phase in physarum is not due to delay in termination of s-phase.it has been known for several years that inhibition by 5'-fluorodeoxyuridine (fdurd) of dna synthesis in plasmodia of physarum polycephalum delays subsequent nuclear mitosis. to test whether this delay is due to delay in the termination of s-phase, we blocked dna synthesis with fdurd + uridine for 3 h at different stages of s-phase, and in plasmodia with different cycle times. the results show that in short-cycling plasmodia the delay in mitosis can be as long as 9 h, despite little delay in ter ...19826211461
physarum myosin light chain binds calcium.myosin from the slime mold physarum polycephalum contains three sizes of polypeptides: a heavy chain and two light chains, lc-1 and lc-2. using a simple qualitative test for calcium binding by comparing electrophoretic migration of the polypeptides in sodium dodecyl sulfate (sds) acrylamide gels in the presence and absence of calcium, we have found that physarum myosin light chain lc-2 migrates with an apparent molecular weight of 16,900 daltons in the presence of the metal ion chelator ethylene ...19806216954
non-histone proteins preferentially associated with transcriptionally active chromatin of physarum polycephalum. 19826217699
physical relationship between replicons and transcription units in physarum polycephalum.electron microscope spread preparations of nuclear chromatin derived from early s-phase of physarum reveal 'beads on a string' for nonreplicated and a portion of newly replicated chromatin. many of the early replicons contain transcription units as visualized by nascent transcripts. they are, in most cases, arranged in continuous length gradients on both newly replicated strands of chromatin, the putative origin of replication being within the transcription unit. preferential release of dna as a ...19826217973
intron within the large rrna gene of n. crassa mitochondria: a long open reading frame and a consensus sequence possibly important in splicing.we describe the sequence of the 2295 nucleotide long intron and 245 nucleotides of the flanking exon sequences within the large (24s) rrna gene of neurospora crassa mitochondria. the intron contains a long open reading frame, which could correspond to ribosomal protein s5. comparison with the corresponding intron of the large rrna gene of yeast mitochondria reveals a single highly homologous 57 nucleotide long sequence, including the sequence (formula; see text), which is present in virtually al ...19826218884
ca2+-dependent actin-binding phosphoprotein in physarum polycephalum. subunit b is a dnase i-binding and f-actin capping protein.physarum contains at least two distinct dnase i-binding proteins, i.e. actin and cap 42 (a + b). the latter, a tight (1:1) complex of cap 42 (a) and cap 42 (b) (maruta, h., isenberg. g., schreckenbach, t., hallmann, r., risse, g., schibayama, t., and hesse, j. (1983) j. biol. chem. 258, 10144-10150), is a ca2+-dependent f-actin capping protein. dnase i binds to cap 42 (b) but not to cap 42 (a). consequently, dnase i-agarose was used for an affinity-purification of cap 42 (a + b), after its separ ...19846232274
differentiation response of physarum polycephalum to macrocysts at various times in nuclear cycle.macrocyst (spherule) formation was induced in synchronized suspension cultures of microplasmodia of physarum polycephalum under conditions where dna synthesis was inhibited. plasmodia in early g2 phase of nuclear cycle were able to differentiate to spherules in the presence of an inhibitor of dna synthesis, whereas those in late g2 phase required another round of dna replication before they could enter into the spherulation process. these facts suggest that commitment to dna synthesis occurred a ...19846233167
purification and enzymatic characterization of three endodnase isoenzymes from physarum polycephalum.three alkaline dnases, a, b, and c, with preference for the digestion of double-stranded dna (dsdna) were partially purified from microplasmodia of physarum polycephalum. they were very similar but differed in their isoelectric points. these were ph 5.8 for dnase a, 7.1 for dnase b, and 9.1 for dnase c. all three enzymes consisted of a single polypeptide chain with a molecular weight of 16,000 to 17,000, which readily formed high molecular weight complexes with low enzyme activity. these complex ...19806244270
kinetics of nuclease digestion of physarum polycephalum nuclei at different stages of the cell cycle.the kinetics of nuclease digestion of physarum polycephalum nuclei by staphylococcal nuclease and dnase i has been studied at different stages of the cell cycle. significant differences in the digestion behaviour of nuclei from metaphase and interphase have been detected with dnase i but not with staphylococcal nuclease. furthermore the structure of newly replicated dna in s phase differs from the bulk in that it is more easily degraded to acid-soluble products by either staphylococcal nuclease ...19806244949
[activity of protein kinases and phosphodiesterases in the cell cycle of ph. polycephalum]. 19806246974
[effects of some protein kinases, cyclic nucleotides and specific inhibitors of phosphorylation on the mitotic cycle of physarum polycephalum].the true slime mould physarum polycephalum was treated with various agents by spraying them upon the cell surface 4 hrs before the second synchronous mitosis. the onset of mitosis was considerably approximated after the plasmodium treatment with protein kinases from rat hepatoma or ph. polycephalum at the late g2 phase. the catalytic and regulatory subunits of camp-dependent pig brain protein kinase caused retardation of mitosis, while the holoenzyme, casein kinase and alkaline phosphatase did n ...19806246981
nad turnover in microplasmodia of physarum polycephalum.the rate of nad turnover in microplasmodia of physarum polycephalum was investigated using a double labeling technique with (14c)-adenine or adenosine and (3h)-nicotinamide. the half-life of an nad molecule in physarum was estimated to be 25 min, which is shorter than in either e. coli or human cell lines. the half-life of nad in the presence of an inhibitor of nadase and poly adpr synthase, 5-methylnicotinamide, was also investigated, but found to be indistinguishable from controls. the possibl ...19806248571
processing of ribosomal precursor rnas in physarum polycephalum.the processing of intermediates of physarum rrna has been investigated using two cloned rdna restriction fragments as sequence specific probes. the size of the largest stable pre-rrna detected is 11.8 kb, as determined by denaturing gel electrophoresis. r-loop analysis revealed that this pre-rrna fraction mainly consists of transcripts which do not contain the two insertion sequences present in the 26 s gene. however, a small number of molecules are found which still contain one or the other, or ...19806253887
cyclic amp in the cell cycle of physarum polycephalum.cyclic amp, [3h]thymidine incorporation, and dna content were measured in the cell cycle of physarum polycephalum. a sensitive radioimmunoassay was employed to assay cyclic amp so that plasmodia could be assayed individually. in contrast to previously published results (lovely, j.r. and threlfall, r.j. (1976) biochem. biophys. res. commun. 71, 789-795), no pre-mitotic peak of cyclic amp was detected. in seven experiments levels of cyclic amp showed only small changes in individual experiments an ...19806256004
sequence organisation in nuclear dna from physarum polycephalum: methylation of repetitive sequences.nuclear dna from the slime mould physarum polycephalum is digested by the restriction endonuclease hpaii to generate a high molecular weight and a low molecular weight component. these are referred to as the m+ and the m- compartment, respectively. sequences that are present in the m+ compartment are cleaved by mspi, the restriction enzyme isoschizomer of hpaii, thus showing that the recognition sequences for these enzymes in m+ dna contain methylated cpg doublets. the distribution of repetitive ...19816262717
nucleotide sequence of a ribosomal rna gene intron from slime mold physarum polycephalum.the physarum polycephalum 26s ribosomal rna gene contains two intervening sequences (introns). the dna sequence of one of these introns was analyzed together with that of its flanking regions (exons). in addition, the nucleotide sequence of the corresponding region of the reverse transcript of 26s rrna was determined, and from comparisons of both sequences the precise location and size of the intron were determined. our findings, when compared with those for tetrahymena and chlamydomonas rrna ge ...19816262791
[cyclic nucleotides in the regulation system of cell proliferation and differentiation].the paper deals with certain aspects in the role of cyclic nucleotides in cell differentiation and proliferation. the content of cyclic nucleotides and activity of protein kinases are determined for the cell cycle stages of a synchronous plasmodium culture of true myxomycete physarum polycephalum. studies in the biological role of the brain camp-dependent protein kinase show that during phosphorylation of nuclei from the brain and subsequent isolation of chromatin its matrix activity is higher t ...19816266105
methylation of nuclear dna in physarum polycephalum.the restriction endonucleases hpaii and hhai, whose action is inhibited by the presence of methylated base analogues at the recognition sequences in the dna substrate, were used to investigate the distribution of 5-methylcytosine in nuclear dna from physarum polycephalum. physarum dna is digested into two fractions by these enzymes: a low-molecular-weight (m--) compartment comprising 80% of the dna, and a high-molecular-weight (m+) compartment containing 20% of the dna. the dna fraction showing ...19806269534
structural homogeneity of mitochondrial dna in the mitochondrial nucleoid of physarum polycephalum.mitochondrial dna (mtdna) of physarum polycephalum was isolated gently by cscl centrifugation. the mtdna was linear with molecular weights ranging from 25 . 10(6) to 45 . 10(6) and heterogeneous in size. nevertheless, thermal transition profiles of the mtdna suggested that this dna fraction was more homogeneous than nuclear dna. exhaustive digestions of this dna with restriction endonucleases yielded unique fragments, and then the total of their molecular weights of each digest was around 45 . 1 ...19826279157
phosphorylation of ribosomal proteins s3, l1 and l24 during spherulation in physarum polycephalum.the phosphate content of ribosomal proteins s3, l1 and l24 has been determined in the course of spherulation of physarum polycephalum. the major phosphoprotein, s3, was completely dephosphorylated after 4 h of differentiation. the phosphate content of l1 and l24 was not altered during the differentiation. the cellular level of atp remained constant for at least 5 h. a 3-fold reduction of cyclic amp concentration occurred in the first hour, followed by a slow increase to a final value of twice th ...19826282330
nucleotide sequence of physarum polycephalum 5.8s rrna gene and its flanking regions.the nucleotide sequence of physarum polycephalum 5.8s rrna gene and its flanking regions has been determined. the homologies of the 5.8s rrna sequence with those of saccharomyces, chlamydomonas and xenopus were 56%, 50% and 52%, respectively. in spite of these relatively low homologies, its possible secondary structure was very similar to those of other species.19826283479
accessibility of ribosomal genes to trimethyl psoralen in nuclei of physarum polycephalum.we have probed the accessibility of the genes for rrna in physarum polycephalum by using the photoreactive dna cross-linking agent 4,5',8-trimethyl psoralen. nuclei isolated from actively growing physarum were treated with trimethyl psoralen and irradiated with 360-nm light in order to form cross-links. the palindromic, extrachromosomal rdna then was isolated, and the positions of cross-links were determined by electron microscopy of the dna under totally denaturing conditions. the results indic ...19826287230
different levels of dna modification at 5'ccgg in murine erythroleukemia cells and the tissues of normal mouse spleen.the dna of a friend erythroleukemic cell line (clone ds-19) and that of mouse spleen from which it was derived were compared with respect to modification at 5'ccgg. methylation patterns in clone ds-19 dna were very different from those in normal spleen dna. our results suggest that the mechanism by which the internal cytosine in the 5'ccgg sequence is modified has been partially inactivated in clone ds-19. we observed a general decrease of about two-fold in total modification at this site in ds- ...19826289271
phosphorylation of ribosomal proteins during the cell cycle of physarum polycephalum.physarum polycephalum has been used as a model system to study the phosphorylation of ribosomal proteins during the cell cycle. the results showed that the phosphate content of s3, the major ribosomal phosphoprotein in this organism, was constant during all phases of the cell cycle. no additional ribosomal phosphoproteins were observed. these results differ significantly from those reported earlier by rupp, r.g., humphrey, r.m. and shaeffer, j.r. (biochim. biophys. acta (1976) 418, 81-92) and su ...19826289900
[comparative enzymatic study on the structure of chromatin in the nuclei of the growing microplasmodium of physarum polycephalum].the structure of chromatin in the growing myxomycetes p. polycephalum can be interpreted on the basis of three types of substructure: (i) soluble in a low ionic strength buffer and 2 mm edta (i), (ii) soluble in 0.6 m nacl (ii) and (iii) non-soluble and nuclease-insensitive (iii). the ratio of these structures in the nuclear pellet obtained after autolysis was found to be 71 : 0, 4 : 12 for the young and 7.7 : 62 : 20.6 for the old cultures, respectively. the ageing of the culture involves trans ...19826289925
mendelian analysis of the organization of actin sequences in physarum polycephalum. 19826294303
isolation and characterization of diadenosine 5',5"'-p1,p4-tetraphosphate pyrophosphohydrolase from physarum polycephalum.a new enzyme that hydrolyzes diadenosine 5',5"'-p1,p4-tetraphosphate has been purified by a factor of 250 from the acellular slime mold physarum polycephalum. activity was assayed radioisotopically with [3h]ap4a. isolation of the enzyme was facilitated by dye-ligand chromatography. the enzyme symmetrically hydrolyzes ap4a to adp and exhibits biphasic kinetics for the substrate with values for the apparent km of 2.6 micro m and 37 micro m. the two values of vmax differ by a factor of 10. mg2+, ca ...19826295456
diadenosine 5',5"'-p1,p4-tetraphosphate pyrophosphohydrolase from physarum polycephalum. substrate specificity.the substrate specificity of diadenosine 5',5"'-p1,p4-tetraphosphate pyrophosphohydrolase from physarum polycephalum for dinucleoside polyphosphates has been determined by high-performance liquid chromatography (hp-lc). elution of a strong anion-exchange resin with a ph and ionic strength gradient of ammonium phosphate separates a series of monoadenosine and diadenosine polyphosphates. most of the corresponding guanine nucleotides are also resolved on this hplc system. one mole each of ap4a and ...19826295457
substrate specificity and mode of action of the zinc-metallo nuclease from physarum polycephalum.the alkaline zinc-metallo nuclease of physarum polycephalum is an endonuclease with a high specificity for single-stranded nucleic acids. single-stranded dna was cleaved at least 6,000 times faster than double-stranded dna under identical conditions. in the supercoil-induced single-stranded region of form i pm2 dna only a single nick was made. the nuclease showed nucleotide specificity. poly(a), poly(i), and poly(dt) were preferentially hydrolyzed. product analysis showed that it acted by an end ...19826296065
h1 histone kinases from nuclei of physarum polycephalum. 19836299335
structure of the central spacer region of extrachromosomal ribosomal dna in physarum polycephalum. 19826300409
sequence and hairpin structure of an inverted repeat series at termini of the physarum extrachromosomal rdna molecule.the termini of the 61 kb palindromic rdna molecules of physarum polycephalum possess a series of multiple inverted repeats in which are located specific single-strand gaps and tightly attached protein. after treating rdna with s1 nuclease, we have cloned several 5 kb eco ri terminal restriction fragments. sequencing of more than 800 nucleotides from the end of one such clone reveals the presence of six to ten tandemly repeated units averaging 140 +/- 4 bp in length and flanked by hae iii sites. ...19836301691
complete nucleotide sequence of the 26s rrna gene of physarum polycephalum: its significance in gene evolution.the complete nucleotide sequences of the 5.8s and 26s rrna genes of physarum polycephalum and the transcribed spacer between them were determined. comparison of the sequences with those of the escherichia coli 23s rrna and yeast 26s rrna genes showed that there are 16 highly homologous regions in the sequences of physarum and e. coli and that eukaryotes have some eukaryote-specific extra sequences. the sequence immediately following the 5.8s-like region of e. coli 23s rrna was found to be highly ...19836304693
myosin heavy chain kinase inactivated by ca2+/calmodulin from aggregating cells of dictyostelium discoideum.soluble myosin heavy chain kinases (mhc kinases) were partially purified from growth phase and aggregation-competent cells of dictyostelium discoideum. in the aggregation-competent cells, two mhc kinases were distinguishable. one of these enzymes, called mhc kinase ii, was inactivated by ca2+ and calmodulin in a highly temperature-dependent reaction. a mhc kinase found in growth phase cells did not have these regulatory properties. substrate specificities were analysed for mhc kinase ii and for ...19836313344
an abundant family of methylated repetitive sequences dominates the genome of physarum polycephalum.a significant portion (20%) of the physarum genome can be isolated as a hpaii-resistant, methylated fraction. cloned dna probes containing highly-repeated sequences derived from this fraction were used to define the pattern of structural organisation of homologous repeats in physarum genomic dna. it is shown that the probes detect an abundant, methylated family of sequences with an estimated genomic repetition frequency greater than 2100, derived from a large repeated element whose length exceed ...19836316271
5-methyldeoxycytidine in the physarum minichromosome containing the ribosomal rna genes.5-methyldeoxycytidine (5mc) was analyzed by high pressure liquid chromatography (hplc) and by restriction enzyme digestion in rdna isolated from physarum polycephalum. rdna from physarum m3c strain microplasmodia has a significant 5mc content (about half that of the whole genomic dna). this rdna contains many c5mcgg sites because it is clearly digested further by msp i than by hpa ii. however, most 5mc is in other sites. in particular, alternating cg sequences appear to be highly methylated. hpl ...19846322108
direct repeats surrounding the ribosomal rna genes of physarum polycephalum.sequence homology was found between the external transcribed spacer and the terminal non-transcribed spacer of physarum polycephalum rdna. the homologous sequences were located 2kb upstream from the 19s rrna gene and 0.3kb downstream from 26s rrna gene, respectively, and were arranged in a direct repeat manner. sequence analyses showed that the direct repeats consisted of two parts: one was sequences of about 130bp which showed over 90% sequence homology with each other. the other consisted main ...19846322132
localization and dna sequence around the initiation site of ribosomal rna transcription in physarum polycephalum.we have used s1 nuclease to map the initiation site of ribosomal rna transcription in the acellular slime mold physarum polycephalum, and we have determined the sequence of 1011 nucleotides surrounding the start site. consistent with others' observations, there is little homology with the comparable region of other species. as predicted by previous restriction mapping, direct repeats roughly 30 base pairs in length are present upstream of the initiation site and a 148 base pair duplication occur ...19836324087
a transposon-like dna fragment interrupts a physarum polycephalum histone h4 gene.a recombinant dna library was screened for histone h4 genes using a sea urchin probe. one recombinant was analysed by restriction enzyme mapping and southern blotting. the complete dna sequence of the h4 histone locus was determined. an 86 base pair interrupting sequence was found within the histone h4 coding sequence. the inserted dna fragment has some characteristics of a transposable element.19846327366
dna methylation in the fungi.a systematic study on the incidence and patterns of cytosine methylation in the fungi has been carried out by restriction and nearest-neighbor analysis of dnas isolated from undifferentiated cells of several fungal species. with respect to dna modification, the fungi appear to be a heterogeneous group, with a 5-methylcytosine content ranging from undetectable levels (less than or equal to 0.1% of cytosine residues methylated in 18 out of 20 species tested) to low but detectable levels (e.g. cong ...19846330093
immunocytochemistry of the acellular slime mold physarum polycephalum. iii. distribution of myosin and the actin-modulating protein (fragmin) in sandwiched plasmodia.the acellular slime mold physarum forms very thin plasmodia when sandwiched between two agar sheets. after extraction with glycerol-containing buffers, suitable objects for immunofluorescence microscopy are obtained, and an analysis of the cytoskeletal and contractile system of physarum becomes possible. plasmodia were stained with antibodies against myosin and fragmin, a protein factor involved in actin filament length regulation. the microanatomy and topography of cellular structures containin ...19836339244
immunocytochemistry of the acellular slime mould physarum polycephalum. i. preparation, morphology, and reliability of results concerning cytoplasmic actomyosin patterns in sandwiched plasmodia.small phaneroplasmodia of physarum polycephalum migrate, under sandwich conditions between two agar sheets and a membrane of cellophane, as thin protoplasmic sheets. this method suitably simulates the situation in the natural habitat of acellular slime moulds; i.e. the narrow clefts of the forest soil. the highly differentiated system of cytoplasmic fibrils displayed under these conditions survives both long-term extraction with glycerol and fixation with methanol, procedures that remove the str ...19836348048
comparison of inhibitors of s-adenosylmethionine decarboxylase from different species.s-adenosyl-l-methionine decarboxylases were purified from rat ventral prostate, yeast (saccharomyces cerevisiae), slime mould (physarum polycephalum) and bacteria (escherichia coli) and tested for inhibition by a variety of nucleosides related to s-adenosylmethionine and by methyl- and ethyl-glyoxal bis(guanylhydrazone). although the enzymes from these different sources are markedly different with respect to activation by cations, the inhibition by nucleosides was quite similar. very little inhi ...19836351843
demonstration of different patterns of microtubule organization in physarum polycephalum myxamoebae and plasmodia using immunofluorescence microscopy.we have used anti-tubulin antibodies and immunofluorescence microscopy to determine the overall distribution of microtubules during interphase and mitosis in both the myxamoebae and plasmodia of the slime mold physarum polycephalum. we have paralleled these observations with electron microscopy of the same stages. the myxamoebae possess a network of cytoplasmic microtubules whilst the coenocytic plasmodium does not possess any cytoplasmic microtubules--at either interphase or mitosis. in plasmod ...19836365559
assay of adenosine 5'-p1-tetraphospho-p4-5"'-adenosine and adenosine 5'-p1-tetraphospho-p4-5"'-guanosine in physarum polycephalum and other eukaryotes. an isocratic high-pressure liquid-chromatography method.a5'pppp5'a has been proposed to serve as a molecular signal that triggers dna replication. when published methods proved to be inadequate for the assay of a5'pppp5'a in physarum polycephalum by h.p.l.c. (high-pressure liquid chromatography), a set of purification procedures was developed that allowed assay of as little as 2pmol of a5'pppp5'a. a5'pppp5'a was purified from cellular extract by covalent boronate chromatography, treated with alkaline phosphatase to hydrolyse residual mononucleotides ...19846370234
secondary structure of mouse 28s rrna and general model for the folding of the large rrna in eukaryotes.we present a secondary structure model for the entire sequence of mouse 28s rrna (1) which is based on an extensive comparative analysis of the available eukaryotic sequences, i.e. yeast (2, 3), physarum polycephalum (4), xenopus laevis (5) and rat (6). it has been derived with close reference to the models previously proposed for yeast 26s rrna (2) and for prokaryotic 23s rrna (7-9). examination of the recently published eukaryotic sequences confirms that all pro- and eukaryotic large rrnas sha ...19846374617
newly-initiated dna isolated from physarum in early s phase consists of nascent-nascent duplexes.we have studied the nature of newly initiated dna released during dna isolation at the beginning of s phase of physarum polycephalum. the released dna was separated from the bulk dna by sedimentation through sucrose gradients. gentle shearing strongly enhanced the release of newly initiated dna. the additionally released material had a larger average molecular weight. buoyant density analysis after labelling with bromodeoxyuridine (brdu) revealed that the released dna consisted of nascent-nascen ...19846383853
calcium binding sites in plasmodia of physarum polycephalum as revealed by the pyroantimonate technique.plasmodia of the acellular slime mold, physarum polycephalum, were treated with an osmium tetroxide fixative containing potassium pyroantimonate to precipitate calcium and thereby localize calcium binding sites and sites of increased calcium concentration. dense calcium pyroantimonate precipitates were detected within the nucleoli. the distribution of these precipitates during interphase and mitosis coincides with the distribution of the unique minichromosomes in physarum, i.e., the numerous sho ...19846386974
effect of the thermal variation on the molecular weight estimation of the acid phosphatase from physarum polycephalum.a binding protein (bp) of nearly 95,000 daltons interacts with the acid phosphatase at the permissive temperature, elevating its molecular weight from 48,000 +/- 2,000 to 136,000 +/- 7,000 in cl and chr strains of physarum polycephalum plasmodia. the same molecule has not been observed in the extracts of m3c viii and k strains. 28-31 degrees c is the critical temperature range for the breaking of enzyme-bp association in cl strains. this critical temperature is higher than 39 degrees c for the e ...19836412770
identification and characterization of axopodial tubulins from echinosphaerium nucleofilum.isolated microtubule protein from axopodia of the heliozoan echinosphaerium nucleofilum, consisting of two major bands on sds-polyacrylamide gel electrophoresis (sds-page), has been compared to axonemal and cytoplasmic tubulins from both animal and non-animal sources. the upper e. nucleofilum protein band migrated faster than the alpha-tubulins of bovine brain and sea anemone sperm tails but with approximately the same electrophoretic mobility as the axonemal alpha-tubulins of tetrahymena pyrifo ...19836413210
consequences of impeding in mitochondrial function in physarum polycephalum. i. reversible effects of anoxia, kcn, and influences of the ca2+ ionophore a-23187.5 mm kcn as well as anoxia have corresponding effects on physarum plasmodia: both induce a disintegration of the plasmalemma invaginations, an increase in cytoplasmic vacuoles, formation of a thick cortical actomyosin layer and an increase of cytoplasmic actomyosin fibrils. both kcn treatment and anoxia cause a temporary increase in the level of the force oscillations and a reversible prolongation of the periods of the contraction-relaxation cycle of cytoplasmic actomyosin. the normal pattern of ...19836416841
contractile and structural reactions to impediments of ca2+-homeostasis in physarum polycephalum.a combined application of 5 mm kcn and 19 microm ca++-ionophore a-23187 leads to pronounced contractures of plasmodial strands of physarum polycephalum. the appearance of the contractures is independent of the amount of ca++ in the external medium. tensiometric registrations of longitudinal contraction activity (isometric regime) reveal an average tension increase of 50 mp compared with the preceding tension level before the addition of kcn and ionophore. this high force output during the contra ...19836423294
distribution and dynamics of fluorochromed actin in living stages of physarum polycephalum.isolated muscle and physarum actins were labeled with various fluorochromes and microinjected into living stages of physarum polycephalum (caffeine-droplets, endoplasmic drops, thin-spread macroplasmodia). subsequent analysis of the intracellular redistribution by fluorescence microscopy, video-enhancement and digital image processing revealed ritc (rhodamineisothiocyanate) actin to be the most reliable molecular probe for the marking of microfilaments. in relaxed caffeine-droplets, the ritc-act ...19846440786
thymidine kinase-deficient mutants of physarum polycephalum. biochemical characterization. 19806444890
[influence of cultivation temperature on the development of functionally active photoregulatory systems in cells of neurospora crassa and physarum polycephalum].illumination with a visible light is known to induce accumulation of colored carotenoid pigments in mycelial cells on neurospora crassa and sporulation of starved macroplasmodia of physarum polycephalum. in both microorganisms, the temperature, at which they are cultivated in the dark, controls manifestation of the photoregulation processes in the cells subsequently exposed to light. the maximal rate of photoinduced accumulation of carotenoids in n. crassa is observed, when the cells are grown i ...19806446087
cyclic fluctuations of the mitotic ca2+-atpase during the cell cycle of the myxomycete physarum polycephalum.the occurrence of the mitotic ca2+-atpase, resembling the enzyme described for higher organisms, is demonstrated in multinuclear plasmodia of the myxomycete physarum polycephalum. the activity of this enzyme undergoes cyclic fluctuations during the synchronous nuclear cycle with a minimum in early g2-phase and a maximum around the time of mitosis.19806446973
an actin-modulating protein from physarum polycephalum. ii. ca++-dependence and other properties.actin modulating (am-) protein from physarum binds as monomer and as a stable heterodimer with one actin molecule to actin and induces the formation of oligomeric actin complexes and short-chained filaments with no definite stoichiometry. while inhibiting the extent of actin polymerization by reducing the size of the aggregates formed, am-protein increases the velocity of polymerization. the am-protein monomer depolymerizes f-actin very rapidly by breaking the filaments into small pieces and oli ...19816451427
ca-dependent inhibitory factor for the myosin-actin atp interaction of physarum polycephalum. 19816460754
rna polymerase activity and template activity of chromatin after butyrate induced hyperacetylation of histones in physarum.we have studied the effect of sodium-n-butyrate on endogenous rna polymerase in physarum polycephalum. 1 mm butyrate strongly reduces rna polymerase activity measured in isolated nuclei or chromatin; both rna polymerase a as well as the alpha-amanitin sensitive rna polymerase b are equally affected. despite a concomitant hyperacetylation of histone h4 the template activity of chromatin, as analyzed by in vitro transcription of the chromatin with exogenous rna polymerase from e. coli or rna polym ...19846462909
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