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Nucleic Acids Research Apr 1990This paper presents a new method for representing DNA sequences. It permits the representation and investigation of patterns in sequences, visually revealing previously...
This paper presents a new method for representing DNA sequences. It permits the representation and investigation of patterns in sequences, visually revealing previously unknown structures. Based on a technique from chaotic dynamics, the method produces a picture of a gene sequence which displays both local and global patterns. The pictures have a complex structure which varies depending on the sequence. The method is termed Chaos Game Representation (CGR). CGR raises a new set of questions about the structure of DNA sequences, and is a new tool for investigating gene structure.
Topics: Animals; Bacteria; Bacteriophages; Base Sequence; DNA; Genes; Humans; Mathematics; Myxomycetes; Plants; Probability; Proto-Oncogenes; Viruses
PubMed: 2336393
DOI: 10.1093/nar/18.8.2163 -
Experimental & Applied Acarology Jun 2021Tyrophagus putrescentiae (Schrank), commonly known as the cereal mite, cheese mite, or ham mite, is a cosmopolitan species reported from various environments in the...
Tyrophagus putrescentiae (Schrank), commonly known as the cereal mite, cheese mite, or ham mite, is a cosmopolitan species reported from various environments in the wild, including soil, plant material and vertebrate nests. It has also been recognized as a common pest of food storages, mycological collections as well as plant and invertebrate laboratory cultures. Laboratory observations indicate that T. putrescentiae feeds on a large range of dermatophytes, yeasts and molds. We have observed the interspecific relation between this mite and several species of true slime molds (Mycetozoa) under laboratory conditions, which confirms the very broad spectrum of feeding habits of T. putrescentiae. Mycetozoans were grown in semi-sterile in vitro cultures and fed with oat flour or oat flakes. Tyrophagus putrescentiae displayed affinity to all macroscopically identifiable stages of the life cycle of Fuligo septica (L.) F.H. Wigg, Physarum polycephalum Schwein and the Didymium sp. complex [Didymium iridis (Ditmar) Fr., Didymium nigripes (Link) Fr. and Didymium bahiense Gottsb.]: live, decaying or dead plasmodia, sporangia, aethalia, spores and sclerotia. The relation carrying symptoms of various types of interspecific interaction, is hypothesized to form an evolutionarily young phenomenon, which not only identifies a new aspect of mycetozoal biology, but also presents the cereal mite as a species of high adaptive potential.
Topics: Acaridae; Accidents; Animals; Life Cycle Stages; Physarum polycephalum; Yeasts
PubMed: 33970406
DOI: 10.1007/s10493-021-00608-4 -
Antimicrobial Agents and Chemotherapy Aug 1973The myxomycete Physarum gyrosum was cultured in its plasmodial stage on agar plates containing 0.025 M phosphate buffer at pH 6.5, 2% bakers' yeast, and 0.2% glucose and...
The myxomycete Physarum gyrosum was cultured in its plasmodial stage on agar plates containing 0.025 M phosphate buffer at pH 6.5, 2% bakers' yeast, and 0.2% glucose and was supplemented with live Escherichia coli. Extracts of these plasmodia contained several antibiotic substances. Antibiotic materials were partially purified by dialysis of the agar medium-mold mixture, evaporation of the dialyzate, and butanol extraction of the residue. Further purification in two paper and two thin-layer chromatographic systems gave one product which was pure in six thin-layer chromatographic systems. Antibiotic activity against some gram-positive and gram-negative bacteria and yeasts was demonstrated with partially purified extracts and a paper-chromatographically separated fraction. One pure antibiotic was effective against Bacillus cereus.
Topics: Anti-Bacterial Agents; Bacteria; Microbial Sensitivity Tests; Myxomycetes
PubMed: 4799591
DOI: 10.1128/AAC.4.2.160 -
Journal of Bacteriology Oct 1966Daniel, John W. (University of Wisconsin, Madison), and Karlee Babcock. Methionine metabolism of the myxomycete Physarum polycephalum. J. Bacteriol. 92:1028-1035....
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-l-methionine, and methionine peptides were the only compounds supporting growth, when substituted for methionine. Other methionine analogues, methyl donors in combination with homocysteine, and intermediates of the cystathionine pathway were not active. Ethionine and S-ethyl cysteine were good methionine antagonists. This myxomycete is apparently unable to synthesize the methyl or S-methyl group, although it still appears able to transmethylate, at least from S-methyl cysteine, and probably from S-adenosyl methionine, which can also serve as a source of adenine.
Topics: Adenine; Amino Acids; Butyrates; Culture Media; Folic Acid; Glycine; Histidine; Methionine; Myxomycetes; Peptides; Sulfur; Vitamin B 12
PubMed: 5951320
DOI: 10.1128/jb.92.4.1028-1035.1966 -
Journal of Bacteriology Jun 1962Daniel, John W. (University of Wisconsin, Madison, Wis.) and Harold P. Rusch. Niacin requirement for sporulation of Physarum polycephalum. J. Bacteriol. 83:1244-1250....
Daniel, John W. (University of Wisconsin, Madison, Wis.) and Harold P. Rusch. Niacin requirement for sporulation of Physarum polycephalum. J. Bacteriol. 83:1244-1250. 1962.-The myxomycete Physarum polycephalum undergoes sexual sporulation if exposed to light after 4 days of incubation in the dark on a salts medium containing niacin, niacinamide, or tryptophan. None of these compounds is required for growth. Quinic acid, shikimic acid, intermediates of the kynurenine pathway, diphosphopyridine nucleotide (DPN), and triphosphopyridine nucleotide (TPN) replace niacin but a number of other tryptophan metabolites do not. Analogues of niacin inhibit sporulation when added at the beginning but not at the end of dark incubation with niacin. Folic acid, p-aminobenzoic acid, and p-aminobenzenesulfonamide inhibit sporulation if added at any time during the incubation or illumination periods. Reduced di- or triphosphopyridine nucleotide, but not DPN or TPN, reverse the p-aminobenzoic acid inhibition but do not replace the light requirement or shorten the dark incubation period. Gluconate and 2-ketogluconate also replace niacin. Glucose, pyruvate, malate, and oxalacetate inhibit the niacin-induced sporulation. Iodoacetate and fluoride do not counteract the glucose effect or inhibit sporulation.
Topics: 4-Aminobenzoic Acid; Folic Acid; Gluconates; Light; Malates; Myxomycetes; Niacin; Physarum polycephalum
PubMed: 13883385
DOI: 10.1128/jb.83.6.1244-1250.1962 -
Brazilian Journal of Biology = Revista... Nov 2015The occurrence of Myxomycetes in Heliconia psittacorum L.f. inflorescences was researched within four conservation units located in Northeast Brazil, aiming at...
The occurrence of Myxomycetes in Heliconia psittacorum L.f. inflorescences was researched within four conservation units located in Northeast Brazil, aiming at evaluating the occupation of this microhabitat in fragments of Atlantic Forest along an altitude between 30-750 m. Inflorescences attached to the plant were examined; dead flowers and bracts were collected to assemble moist chambers (368). Four families, four genera and 10 species were recorded. A preference was evidenced for a basic pH substrate and a predominance of calcareous species (5:1). The composition of the myxobiota in fragments pertaining to altitudes above 400 m was similar and differed significantly from the one found in fragments of lowland forests (<100 m). Physarum compressum and Arcyria cinerea are the most characteristic species of the studied myxobiota.
Topics: Brazil; Forests; Heliconiaceae; Inflorescence; Myxomycetes
PubMed: 26628227
DOI: 10.1590/1519-6984.01714 -
Journal of Bacteriology Nov 1969Spores of Dictyostelium discoideum undergo significant changes in fine structure during germination. The mitochondria progressively become less dense and lose their...
Spores of Dictyostelium discoideum undergo significant changes in fine structure during germination. The mitochondria progressively become less dense and lose their peripherally attached ribosomes, and the tubuli become more pronounced as germination proceeds. During this period, the three-layered spore wall breaks down in two stages: first, the outer and middle layers are ruptured as a unit, and, second, the inner wall is breached. Crystals and dark (lipid) bodies disappear shortly before or during emergence of the myxamoebae. Autophagic vacuoles are found in dormant spores and throughout the entire germination process. The addition of cycloheximide to germinating spores inhibited the loss of the crystals and dark (lipid) bodies. In addition, the drug inhibited the breakdown of the inner wall layer. Cycloheximide did not prevent the formation of the water expulsion vesicle or the apparent function of the autophagic vacuoles.
Topics: Cell Membrane; Culture Media; Cycloheximide; Methods; Microscopy, Electron; Mitochondria; Myxomycetes; Protoplasts; Ribosomes; Spores
PubMed: 5391047
DOI: 10.1128/jb.100.2.1020-1026.1969 -
Journal of Applied Physiology... Jun 2008
Topics: Adaptation, Physiological; Amoeba; Animals; Biological Evolution; Comprehension; Energy Metabolism; Extinction, Biological; Humans; Models, Biological; Myxomycetes; Nonlinear Dynamics; Selection, Genetic; Systems Biology; Thermodynamics
PubMed: 18584788
DOI: 10.1152/japplphysiol.zdg-7945-vpcomm.2008 -
Journal of Bacteriology Mar 1969A method has been developed for growing Physarum polycephalum plasmodia that are 8 to 10 times larger than those obtained in the petri dish cultures used by Nygaard,...
A method has been developed for growing Physarum polycephalum plasmodia that are 8 to 10 times larger than those obtained in the petri dish cultures used by Nygaard, Guttes, and Rusch. In the large-scale procedure, plasmodia were grown in metal trays on a membrane supported by filter paper on stainless-steel screen. Plasmodia were started from a ring of inoculum to allow inward and outward migration and were incubated on a rocker so that nutrient medium would flow back and forth, wetting the undersurface of the plasmodium. Rocker and petri dish cultures had similar growth characteristics: (i) the interphase time between mitoses I and II and between II and III was about 8 hr; (ii) ribonucleic acid and protein increased essentially logarithmically throughout the cell cycle; and (iii) deoxyribonucleic acid increased only during early interphase and it doubled in approximately 3 hr after each mitosis. Rocker cultures were not as nearly synchronous as petri dish cultures and had a range in metaphase time (at mitosis III) within individual plasmodia of 15 to 45 min, as compared with 5 to 10 min in petri dish cultures.
Topics: DNA; Methods; Microbiology; Mitosis; Myxomycetes; Proteins; RNA
PubMed: 5813343
DOI: 10.1128/jb.97.3.1411-1418.1969 -
Optics Express Jul 2010In this paper we report evidence of structural color in Myxomycetes, a group of eukaryotic microorganisms with an uncertain taxonomic position. We investigated the...
In this paper we report evidence of structural color in Myxomycetes, a group of eukaryotic microorganisms with an uncertain taxonomic position. We investigated the Diachea leucopoda, which belongs to the Physarales order, Myxomycetes class, and found that its peridium -protective layer that encloses the mass of spores- is basically a corrugated layer of a transparent material, which produces a multicolored pointillistic effect, characteristic of this species. Scanning (SEM) and transmission (TEM) electron microscopy techniques have been employed to characterize the samples. A simple optical model of a planar slab is proposed to calculate the reflectance. The chromaticity coordinates are obtained, and the results confirm that the color observed is a result of an interference effect.
Topics: Models, Biological; Myxomycetes; Pigmentation
PubMed: 20720990
DOI: 10.1364/OE.18.016055