| on the distribution of myxobacteria in the temperate south america (author's transl). | 60 soil samples from southern chile, mainly from forests and grassland, yielded six species of myxobacteria. in forest soils myxococcus coralloides and myxococcus fulvus occur frequently, in grassland soils myxococcus coralloides and archangium gephyra are predominating. myxococcus virescens, melittangium lichenicola, and cytobacter fuscus have been observed rarely. it is pointed out that due to climate factors a high soil acidity causes the low nuber of myxobacter species. a comparison with the ... | 1978 | 27046 |
| the function of fimbriae in myxococcus xanthus. i. purification and properties of m. xanthus fimbriae. | myxococcus xanthus fimbriae have been purified and characterized as part of a study of the function of fimbriae in this prokaryote. myxococcus xanthus produced two types of fimbriae, termed flaccid (f) and rigid (r) on the basis of electron microscopy. f and r fimbriae differed slightly in their response to ph and freeze-thaw regimes but were similar in their resistance to hydrolytic enzymes, amino acid composition, molecular weight, carbohydrate content, and antigenic determinants. although the ... | 1979 | 43765 |
| morphogenesis in myxococcus xanthus and myxococcus virescens myxobacterales. | 1. myxococcus xanthus b and m. virescens v2 were compared with a view to establishing the control of their morphogenetic cycles. both organisms are typical myxococci and on solid media with low concentrations of nutrient they form fruiting bodies, within which vegetative cells convert to myxospores. ultrathin sections of vegetative m. virescens resembled those of m. xanthus and contained prominent heavily stained bodies, presumed to be polyphosphate granules. shadowed preparations showed fimbria ... | 1976 | 58646 |
| synergism between morphogenetic mutants of myxococcus xanthus. | | 1978 | 98366 |
| synthesis and salvage of purines during cellular morphogenesis of myxococcus xanthus. | intact cells of myxococcus xanthus were examined for de novo purine synthesis and salvage utilization. the cellular uptake rates of radioactive glycine (de novo purine precursor), adenine, and guanine were measured, and thin-layer chromatography and radioautography were used to examine cell extracts for de novo synthesized purine nucleotides. intact vegatative cells, glycerol-induced myxospores, and germinating cells of m. xanthus cw-1 were able to carry out de novo purine and salvage synthesis. ... | 1978 | 101526 |
| incorporation of 32pi into nucleotides, polyphosphates, and other acid-soluble compounds by myxococcus xanthus during myxospore formation. | when glycerol was used to induce myxospore formation in myxococcu xanthus in the presence of 32pi, the label was incorporated into a variety of acid-soluble compounds. incorporation into ribonucleotides was approximately fivefold greater than in vegetative cells or noninducible mutants grown in glycerol. the label was also incorporated into some unknown compounds and material tentatively identified as guanosine tetraphosphate. marked accumulation into polyphosphates, which were present mainly in ... | 1978 | 102632 |
| hemolysin of myxococcus fulvus nk 35 i. production and isolation. | myxococcus fulvus nk 35 has been shown to produce a soluble hemolysin which lysed rabbit, human, horse, and sheep erythrocytes. a medium (varghese's medium) was devised in which a maximum of hemolysin was produced in 6 days at 28 degrees c under static conditions. the lysin was precipitated by complete saturation of the culture filtrate with ammonium sulphate, followed by dialysis against saline. other enzyme systems were destroyed by heating at 100 degrees c. further purification was achieved b ... | 1978 | 104473 |
| purification and effects of fulvocin c, a bacteriocin from myxococcus fulvus mx f16. | fulvocin c is a bacteriocin from myxococcus fulvus mx f16. it has a molecular weight of 4672 and is one of the smallest bacteriocins known. four disulfide bonds give the molecule a tight structure, so that its native form was not attacked by chymotrypsin or pronase. fulvocin c was stable in various organic solvents and could tolerate 80 degrees c in aqueous solution without loss of activity. the killing effect of fulvocin c was observed only at concentrations higher than 0.25 mumol/1. macromolec ... | 1978 | 104692 |
| homology of the gene coding for outer membrane lipoprotein within various gram-negative bacteria. | the mrna for a major outer membrane lipoprotein from escherichia coli was found to hybridize specifically with one of the ecori and one of the hindiii restriction endonuclease-generated fragments of total dna from nine bacteria in the family enterobacteriaceae: e. coli, shigella dysenteriae, salmonella typhimurium, citrobacter freundii, klebsiella aerogenes, enterobacter aerogenes, edwardsiella tarda, serratia marcescens, and erwinia amylovora. however, among the enterobacteriaceae, dna from two ... | 1979 | 104972 |
| gene expression during development of myxococcus xanthus: pattern of protein synthesis. | | 1979 | 108160 |
| iso-branched 2- and 3-hydroxy fatty acids as characteristic lipid constituents of some gliding bacteria. | the fatty acids present in the total hydrolysates of several gliding bacteria (myxococcus fulvus, stigmatella aurantiaca, cytophaga johnsonae, cytophaga sp. strain samoa and flexibacter elegans) were analyzed by combined gas-liquid chromatography and mass spectrometry. in addition to 13-methyl-tetradecanoic acid, 15-methyl-hexadecanoic acid, hexadecanoic acid, and hexadecenoic acid, 2- and 3-hydroxy fatty acids comprised up to 50% of the total fatty acids. the majority was odd-numbered and iso-b ... | 1979 | 118159 |
| biological activity of an antibiotic produced by myxococcus coralloides. | a strain of myxococcus coralloides was isolated which produced an antibiotic active against gram-positive bacteria and also against neisseria sp at high levels of antibiotic. the antibiotic was bactericidal on sensitive growing bacteria. it was inactive on non-growing cells and also on cells whose growth has been stopped by addition of chloramphenicol. strains of s. aureus resistant to several antibiotics, including penicillin and ampicillin, were also sensitive to this antibiotic. | 1979 | 120482 |
| [aquatic myxobacteria (sporocytophaga cauliformis) and the order "myxobacterales" (author's transl)]. | the indicator function of aquatic myxobacteria for the purpose of evaluating drinking water quality as well as their occurrence in sewage effluent make it desirable to describe these hitherto little known organisms in more detail. to this end, a comparative investigation of anaerobic myxobacteria of the genus sphaerocytophaga, two typical representatives of the order myxobacterales (myxococcus fulvus, sporocytophage cauliformis), and a strain ov vitrepscilla (vitroescilla proteolytica) was under ... | 1979 | 120650 |
| [occurrence and distribution of fruiting body-forming myxobacteria in siebengebirge. comparative studies with special reference to characteristic biotypes]. | in the region of the "siebengebirge" near bonn, six characteristic biotopes were studied with respect to the occurrence of fruiting body forming myxobacteria. 23 different species, belonging to the 8 known genera, were found. the number of species in the respective biotopes varied between 6 and 17, the average numbers of species per sampling area were between 2.1 and 10.0. 15 species were found on dung pellets of wild living herbivorous mammals. deciduous forest soils contained 13 species in spr ... | 1979 | 121178 |
| cyclic nucleotides, cyclic nucleotide phosphodiesterase, and development in myxococcus xanthus. | exogenous cyclic nucleotide phosphodiesterase (pd) accelerated fruiting body (fb) formation and increased territory size of aggregates in myxococcus xanthus. both guanosine 3'5'-monophosphate (cgmp) and guanosine 5'-monophosphate (gmp) were antagonistic to the pd effect. adenosine 3'5'-monophosphate (camp) increases fb numbers twofold in the absence but not in the presence of pd. pd induction is not affected by methionine or isoleucine, which inhibit, or by threonine, which stimulates, fb format ... | 1978 | 218712 |
| demonstration of positive chemotaxis to cyclic gmp and 5'-amp in myxococcus xanthus by means of a simple apparatus for generating practically stable concentration gradients. | | 1979 | 231479 |
| gliding motility and actinomycin d sensitivity of fusobacterium nucleatum and other gram-negative rods. | six strains of gram-negative anaerobic fusiform rods (fusobacterium and bacteroides spp.), isolated from deep subgingival locations in humans, were examined for (i) gliding motility in slide cultures, (iii) cell densities on nutrient agar surfaces, and (iii) sensitivity to actinomycin d. known gliding (fbt) and nonmotile (nm) strains of myxococcus xanthus served as controls for the gliding and cell density experiments. in the present study, three strains of gram-negative fusiforms from the oral ... | 1977 | 332633 |
| isolation of sporopollenin from four myxobacteria. | sporopollenin, a resistance material previously found only in algae, fungi, pollen grains, and in some plant spores, has been found in four species of myxococcus. sporopollenin was isolated from vegetative cells and myxospores of the myxobacteria tested but it was not detected in any of the other bacteria tested. | 1977 | 407993 |
| changes in cyclic amp levels during development in myxococcus xanthus. | cyclic amp levels doubled in myxococcus xanthus under conditions in which cells aggregate and form fruiting bodies. in liquid medium, glycerol- or dimethyl sulfoxide-induced sporulating cultures exhibited a sharp but transient rise in cyclic amp concentration after 45 min. | 1978 | 205533 |
| aspartokinase isoenzymes of the fruiting myxobacterium myxoccus xanthus. | two isoenzymes of aspartokinase can be found in extracts of the differentiating bacterium myxococcus xanthus. aspartokinase i is repressed by l-lysine and feedback is inhibited by meso-diaminopimelate and by low concentrations of l-lysine. however, the inhibition by l-lysine is no longer observed at high concentration of this amino acid. aspartokinase ii is repressed and feedback inhibited specifically by l-threonine. both enzymes are stimulated significantly by l-methionine and l-isoleucine; th ... | 1975 | 170969 |
| regulation of development in myxococcus xanthus: effect of 3':5'-cyclic amp, adp, and nutrition. | an assay was developed to study the regulation of fruiting in myxococcus xanthus. the nucleotides, adenosine 3':5'-cyclic monophosphate (cyclic amp) and adenosine diphosphate (adp), were found to greatly stimulate fruiting under the assay conditions. very sharp concentration optima were observed. even under conditions of starvation, these nucleotides greatly increased the number of aggregation sites. nutrition was found to influence fruiting body morphology. the effect of amino acids on the nucl ... | 1975 | 164657 |
| bacteriocins from myxococcus fulvus (myxobacterales). | bacteriocin-like activities were found in several myxococcus fulvus strains. one strain, mx f16, exerted strong inhibitory effects on several myxobacterial strains. synthesis of its bacteriocinic activity could not be induced by mitomycin. electrophoresis and molecular sieve chromatography revealed at least three different bacteriocinic substances of low molecular weight. | 1977 | 412477 |
| site of atpase activity in myxococcus xanthus: lipid requirement for enzyme activity. dedicated to professor dr. w. schwartz on his 80th birthday. | treatment of cells with lysophosphatidylcholine, lysozyme, and phospholipase d removed most of their phospholipids and reduced atpase activity to near zero. addition of a microdispersion of phospholipids restored enzyme activity to various degrees. phosphatidylcholine was most effective in reconstitution experiments, less effective were phosphatidylethanolamine and phosphatidylserine. lipid analyses of cell fractions were possible through separation of cell wall and cell membrane in a sucrose gr ... | 1978 | 151387 |
| two methods of large-scale extraction of an antibiotic produced by myxococcus coralloides. | two methods for the isolation of an antibiotic produced by myxococcus coralloides have been developed: the chloroform extraction method and the charcoal adsorption method. the recovery of antibiotic in each case was 25% and 30%, respectively, by the two methods. although the two methods yield a relative low recovery, the charcoal adsorption method seems more attractive and promising due to its simplicity and economic advantages. | 1979 | 119135 |
| bacteriolytic myxobacteria: parasites or scavengers? | the activity range of an enzymatic preparation from myxococcus xanthus was assayed against some soil and rhizospheric bacteria. the lysis of unequally aged sensitive eubacterial populations, as related to their viability, was investigated and, at last, the often used streak method was checked and the relationship between cell viability and susceptibility to lysis is discussed. | 1977 | 414478 |
| myxobacterial slime and proteolytic activity. | an extracellular protein-polysaccharide-lipide (ppl) complex from exponentially growing cultures of myxococcus virescens was purified by phosphate precipitation and gel chromatography. the high molecular weight slime polymer appeared homogenous upon isoelectric focusing. the ppl complex exhibited proteolytic activity against gelatin and the activity was only partly reduced by heat treatment. the function of the slime polymer as protein denatured was studied. the complex formed micelles similar t ... | 1978 | 414687 |
| myxococcus xanthus mutants with temperature-sensitive, stage-specific defects: evidence for independent pathways in development. | fruiting-body formation in the bacterium myxococcus xanthus consists of a temporal sequence of cellular aggregation and sporulation. to examine the developmental stages more closely, we established synchronous and reproducible conditions for fruiting-body formation. mutants that are temperature sensitive for fruiting-body formation were isolated and analyzed under these conditions. the terminal morphologies of the mutant strains at the nonpermissive temperature were found to resemble intermediat ... | 1979 | 118153 |
| isolation of bacteriophage mx4, a generalized transducing phage for myxococcus xanthus. | | 1978 | 416222 |
| physical characterization of bacteriophage mx4, a generalized transducing phage for myxococcus xanthus. | | 1978 | 416223 |
| developmental induction of myxococcus xanthus myxospores. | myxospore differentiation during the developmental cycle of myxococcus xanthus is characterized by several distinguishable morphological stages. two experimentally useful criteria of myxospore induction are the conversion of vegetative rods to optically refractile short rods or ovoids and the development of resistance to sonic lysis. the use of optical refractility as the first morphological criterion of myxospore induction has facilitated an analysis of induction on developmental plates. the ti ... | 1979 | 115838 |
| gene transfer to myxobacterium by escherichia coli phage p1. | myxococcus xanthus is a bacterium with an interest for studies of development because it has an organized multicellular phase in its life cycle. bacteriophage pl can adsorb to m. xanthus and inject its dna into this organism despite the wide taxonomic gap separating myxococcus from escherichia coli, the source of pl. a specialized transducing derivative of pl, called plcm, can carry a gene for chloramphenicol resistance from e. coli into m. xanthus and generate unstable drug-resistant strains. | 1975 | 803710 |
| rifampin-resistant mutants of myxococcus xanthus defective in development. | rifampin, an antibiotic which is known to bind to and inhibit rna polymerase, was used to probe the molecular regulation of development in myxococcus xanthus. rifampin-resistant mutants were screened for defects in fruiting-body formation. about 20% of the isolates in the initial screenings showed major defects in developmental aggregation or sporulation. eleven independent mutants with wild-type growth rates and stable phenotypes were analyzed by transduction. in these strains, the rifampin-res ... | 1979 | 104962 |
| transduction of myxococcus virescens by coliphage p1cm: generation of plasmids containing both phage and myxococcus genes. | chloramphenicol-resistant myxococcus virescens were obtained by infecting myxococci with escherichia coli specialized transducing phage p1cm. the drug-resistant myxococci were phenotypically unstable. they contained more than one type of plasmid; these plasmids were not found in the parent strain. chloramphenicol-resistant e. coli were obtained by transformation with either a fraction of myxococcal dna containing the plasmids or with p1cm prophage dna. these transformants contained plasmids. esc ... | 1978 | 103996 |
| transfer of drug resistance to myxococcus from bacteria carrying drug-resistance factors. | resistance to chloramphenicol was successfully transferred from strains of escherichia coli carrying r factors representative of compatibility groups f, w, s and n to strains of myxococcus xanthus and m. fulvus. resistance to kanamycin was transferred from an r factor in group s, and to neomycin from an r factor of group p. myxobacterial strains differed in their capacity to take up the resistances and also in the stability of the resistance character. strains of m. fulvus were obtained that acq ... | 1975 | 806655 |
| comparison of spontaneous, uv-induced, and nitrosoguanidine-induced mutability to drug resistance in myxobacteria. | the uv survival curves of different strains of myxobacteria exhibited shoulders; in the case of polyangium luteum, an unusual double shoulder appeared. repair inhibitors like acriflavine, caffeine, and coumarin reduced the survival of uv-irradiated cells if the drugs were incorporated in the post-irradiation plating medium. the shoulders were reduced, but the final inactivation slopes were not affected by the repair inhibitors. those strains that were resistant to uv were also more resistant to ... | 1978 | 99434 |
| systematic isolation of transducing phages for myxococcus xanthus. | | 1978 | 97862 |
| on the utilization in vivo of lycopene and phytoene as precursors for the formation of carotenoid glucoside ester and on the regulation of carotenoid biosynthesis in myxococcus fulvus. | during th logarithmic phase of growth of the myxobacterium myxococcus fulvus the specific carotenoid content and the molar ratio of the two main carotenoids keto-torulene (3',4'-didehydro-beta,psi-caroten-4-one, 15%) and myxobacton ester (1'-glucosyloxy-3',4'-didehydro-1',2'-dihydro-beta,psi-caroten-4-one ester, 80%) are highly constant. when the formation of these carotenoids was prevented by an inhibitory block at the level of phytoene desaturation, the normal specific content is rapidly reach ... | 1975 | 809283 |
| myxobacterial hemagglutinin: a development-specific lectin of myxococcus xanthus. | fruiting body formation in the bacterium myxococcus xanthus consists of a temporal sequence of cellular aggregation and sporulation. during the period of cellular aggregation, a major new development-specific protein that has lectin-like activity is synthesized. this protein, called myxobacterial hemagglutinin (mbha), was able to agglutinate sheep or guinea pig erythrocytes but not horse, ox, chicken, or human erythrocytes. mbha was undetectable in extracts of vegetative cells, cells starved in ... | 1979 | 93278 |
| mutants of myxococcus xanthus insensitive to glycerol-induced myxospore formation. | mutants of myxococcus xanthus fbt unable to form myxospores in response to 0.5 m glycerol arise spontaneously with a frequency of 1--3 x 10(-5). these mutants are designated glc. ultraviolet mutagenesis increases the frequency to a maximum of 7% of the survivors. the reversion frequency following ultraviolet irradiation of spontaneous glc mutants is less than 10(-3). of four glc mutants examined, none form myxospores in response to the alternative inducers, ethylene glycol and dimethyl sulphoxid ... | 1975 | 53038 |
| the function of fimbriae in myxococcus xanthus. ii. the role of fimbriae in cell-cell interactions. | anti-fimbriae antiserum specifically inhibited swarming but no gliding motility per se in myxococcus xanthus. however, formation of motile aggregates on agar and clumps in liquid media correlated with the presence of fimbriae. ethylenediaminetetraacetic acid which inhibited swarming also inhibited fimbriae formation. direct electron-microscopic observations revealed that fimbriae establish contact with apposing cell surfaces. intact but not depolymerized fimbriae exhibited hemagglutination activ ... | 1979 | 43768 |
| social gliding is correlated with the presence of pili in myxococcus xanthus. | myxococcus xanthus, an organism whose motility involves cell interactions, normally bears pili. myxococcal pili are found only at cell poles, are less than 10 nm in diameter, and may be longer than a cell. myxococcus has two basic patterns of cell movement, adventurous (a-motility) and social (s-motility). pili are found to be completely correlated with the presence of s-motility. (the s-motility pattern has many groups of cells, almost no single cells, and is governed by a set of genes called s ... | 1979 | 42906 |
| purification and partial characterization of an antibiotic produced by myxococcus coralloides. | a strain of myxococcus coralloides producing an antibiotic capable of inhibiting growth of gram-positive bacteria was isolated. antibiotic production occurred during vegetative growth but not during myxospore formation. the antibiotic was extracted from the growth medium with chloroform and purified by adsorption on silicic acid and by preparative silica gel thin-layer chromatography. the purified antibiotic showed a resistance to heat, acid, alkali and proteolytic enzymes. chromatographic and e ... | 1979 | 37227 |
| dna of myxococcus bacteriophage mx-1: macromolecular properties and restriction fragments. | 1. bacteriophage mx-1 is a virulent dna phage whose hosts include strains of myxococcus xanthus, m. fulvus and m. virescens. dna was extracted from purified phage preparations. the molecular weight of phage dna was measured by sedimentation-velocity and by rate-zonal ultracentrifugation. the apparent molecular weight was found to vary for reasons discussed in the text. from rate-zonal ultracentrifugation, using calibrated sucrose gradients, the molecular weight was calculated to be 149 (+/-22) x ... | 1976 | 818975 |
| restriction in myxococcus virescens. | 1. the plating efficiency of bacteriophage mx-1 on myxococcus xanthus strains a and b and m. virescens v2 were compared. comparison of strains v2 and a suggest that v2 is restrictive and a is not (restriction coefficient was approximately 8). a derivative of m. virescens v2 (strain v2-9) was obtained by repeated exposure of strain v2 to ultraviolet radiation. strain v2-9 was also unrestrictive. strain b is apparently unrestrictive too but analysis of phenotypic changes in phage derived from host ... | 1976 | 818976 |
| phage and defective phage of strains of myxococcus. | 1. phage-like particles were found in the supernatants of cultures of strains of myxococcus xanthus, m. virescens and m. fulvus. the largest number of such particles was associated with m. virescens v2. most of the particles were similar in morphology to the virulent myxococcus phage, mx-1. 2. several new phages were isolated from soil and animal droppings. a new phage was isolated from cultures of m. virescens v2. all resembled phage mx-1 in morphology and were related to phage mx-1 serological ... | 1976 | 821449 |
| stimulation of fruiting body formation of myxococcus virescens thaxter (myxobacterales) in crude culture by addition of salt. | | 1978 | 25514 |
| fructification & antagonistic effect of myxobacteria on eubacteria: lytic effect & fruiting body formation of myxococcus, chondrococcus & angiococcus spp. | | 1976 | 821856 |
| evidence for motility-related fimbriae in the gliding microorganism myxococcus xanthus. | an electron-microscopic examination of negatively stained preparations from cell lysates of myxococcus xanthus and in situ samples of myxococcus xanthus, myxococcus virescens, and myxococcus fulvus has demonstrated the presence of polar fimbriae, about 8.5 nm in diameter, on motile but not nonmotile cells. | 1976 | 824039 |
| purification and properties of an extracellular protease from myxococcus virescens. | an extracellular protease from myxococcus virescens was purified by phosphate precipitation, gel exclusion, and ion-exchange chromatography. the enzyme appeared homogeneous upon disc electrophoresis. the molecular weight of the protease was estimated to be 26,000. the enzyme was rapidly inactivated by ethylenediaminetetraacetate, but the activity could be partially restored by divalent cations. diisopropylphosphorofluoridate inhibited enzyme activity completely. michaelis-menten kinetics were ob ... | 1978 | 22536 |
| myxospore coat synthesis in myxococcus xanthus: enzymes associated with uridine 5'-diphosphate-n-acetylgalactosamine formation during myxospore development. | activities of the enzymes glutamine synthetase (ec 6.3.1.2.), glucosamine 6-phosphate acetyltransferase (ec 2.3.1.4.), uridine 5'-diphosphate (udp)-n-acetylglucosamine pyrophosphorylase (ec 2.7.23.), udp-n-acetylglucosamine 4-epimerase (ec 5.1.3.7.), fructose 1,6-diphosphate phosphatase (ec 3.13.11.), l-glutamine-fructose 6-phosphate transamidase (ec 5.3.1.19.), alkaline phosphatase (ec 3.1.3.1.), and malic dehydrogenase (ec 1.1.1.37) were assayed in partially purified extracts prepared at diffe ... | 1977 | 19417 |
| nuclear activity and cell division in the microcysts of myxococcus fulvus demonstrated by electron micrography of sections. | electron micrographs of sectioned fruiting bodies confirm that, in myxococcus fulvus, approximately 10% of mature microcysts show appearances interpretable as typical bacterial nuclear activity and cell division. this suggests a simple mechanism for fruiting body development, and its existence bears upon the validity of the classical descriptions of microcyst maturation in myxobacteria. | 1976 | 827459 |
| myxospore coat synthesis in myxococcus xanthus: in vivo incorporation of acetate and glycine. | myxospore coat synthesis in myxococcus xanthus was studied by incorporation of [(14)c]acetate into intermediates in the biosynthesis of coat polysaccharide and into acid-insoluble material during vegetative growth and after glycerol induction of myxospores. during short labeling periods at 27 degrees c, the radioactivity was shown to be located primarily in n-acetyl groups rather than sugar moieties. two hours after glycerol induction, the pools of n-acetylglucosamine 6-phosphate and uridine 5'- ... | 1977 | 408325 |
| [investigations on the structure of the sphingolipids of the genus bacteroides (author's transl)]. | in 1972 fritsche and thelen have described the difference between the structure of the komplex lipids of the genus bacteroides and the genus sphaerophorus. further investigations of fritsche demonstrated the possibility of grouping gramnegative anaerobes into the genus bacteroides in spite of the fact, that one of the final products of metabolism of these strains is butyric acid. these strains are the so-called butyric acid producing bacteroides. this paper describes the structure of the still u ... | 1975 | 1202872 |
| effect of temperature on the growth of myxococcus xanthus. | the cardinal growth characteristics of myxococcus xanthus were examined from 14 to 40 degree c, and the examinations indicated that the organism is mesophilic in character. the maximum growth rate (0,3 doublings per h) was between 34 and 36 degree c and the temperature characteristic (micron) is 17,000 cal/mol (71,162 j/mol). | 1977 | 404288 |
| developmentally induced autolysis during fruiting body formation by myxococcus xanthus. | the developmental events during fruiting body construction by the myxobacterium m. xanthus is an orderly process characterized by several sequential stages: growth leads to aggregation leads to formation of raised, darkened mounds of cells leads to autolysis leads to myxospore induction. the temporal sequence of autolysis followed by myxospore induction is consistent with the interpretation that developmental autolysis provides essential requirements for the surviving cells to induce to myxospor ... | 1977 | 402359 |
| effect of mechanical removal of pili on gliding motility of myxococcus xanthus. | gliding motility of myxococcus xanthus is governed by both the adventurous (a) and the social (s) motility gene systems. the presence of pili has previously been shown to be correlated with a genetically intact s-motility system (d. kaiser, proc. natl. acad. sci. usa 76:5952-5956, 1979). the purpose of the present work was to study the direct effect of mechanical removal of pill on the social motility of m. xanthus. depiliation resulted in (i) a loss of streaming motility of a- s+ mutants, i.e., ... | 1992 | 1353759 |
| cell density-dependent growth of myxococcus xanthus on casein. | when myxococcus xanthus fb was grown on 0.2% casein it exhibited a phenomenon we call cooperative growth. that is, above 104 cells per ml, both strains that were studied exhibited increasing growth rates as a function of increasing cell numbers. between 104 and 107 cells per ml, the mean doubling times of strains ys and tns decreased from 15.2 to 8 h and 26 to 8.5 h, respectively. the extracellular proteinase activity of the two strains was equivalent and directly proportional to cell number. co ... | 1977 | 402357 |
| glucan common to the microcyst walls of cyst-forming bacteria. | chemical analysis indicated that d-glucose is tha major neutral monosaccharide present in the microcysts of a range of gram-negative bacteria. varying amounts of other neutral sugars were found. the glucose was mainly present as a glucan that could be extracted from microcysts of representative strains with alkali or mild acid treatment. the glucan could be identified as an alpha-1,3-linked polymer on the basis of (i) periodate resistance of the extracted polymer and the material present in micr ... | 1977 | 402353 |
| biosynthesis and self-assembly of protein s, a development-specific protein of myxococcus xanthus. | myxococcus xanthus is a gram-negative bacterium that has a complex life cycle including a temporal sequence of cellular aggregation, mound formation, and myxosporulation. during development, protein s (molecuar weight 23,000) is induced and accumulates in very large amounts. protein s was found in the soluble fraction of early developmental extracts and in the insoluble fraction in later extracts. this insoluble form of protein s can be solubilized by the addition of 1 m nacl at 0 degrees c to e ... | 1979 | 284334 |
| a quantitative assay to study cell movement in the myxobacteria. | a simple quantitative assay has been developed to test the rate of cell movement of myxobacteria. the assay employs an agar surface and at no time are the cells cultured in a liquid environment. isolation of a rate-increasing substance(s) from fruiting myxococcus xanthus is reported. the understanding of the aggregative process in these bacteria will be aided by characterization of the chemotactic system. | 1977 | 408365 |
| similarity between the myxococcus xanthus and stigmatella aurantiaca reverse transcriptase genes associated with multicopy, single-stranded dna. | to determine the evolutional relationship of bacterial retroelements of myxococcus xanthus and stigmatella aurantiaca, the nucleotide sequence of 3,060 bases encompassing msr, msd, and the upstream region of msd (downstream of msr) of s. aurantiaca dw4 was determined and compared with the same region from m. xanthus. an open reading frame was found 92 bases upstream of msd which encoded a polypeptide of 480 amino acid residues having 73% identity with the reverse transcriptase of m. xanthus. tog ... | 1992 | 1372604 |
| in vivo production of a stable single-stranded cdna in saccharomyces cerevisiae by means of a bacterial retron. | gram-negative bacteria such as myxococcus xanthus, stigmatella aurantiaca, and escherichia coli contain retroelements called retrons. retrons consist of the msr-msd region and the gene for reverse transcriptase (rt), which are essential for the production of the branched rna-linked ms-dna (multicopy single-stranded dna). in this study, we attempted to produce msdna in the yeast saccharomyces cerevisiae. retron ec67 from e. coli, which is responsible for the production of msdna-ec67, was cloned u ... | 1992 | 1378616 |
| intracellular, periodic structures in the gliding bacterium myxococcus xanthus. | electron microscopic observations of thin sections of myxococcus xanthus vegetative cells revealed the presence of cytoplasmic bundles of 4- to 5-nm-diameter filaments running longtitudinally below the cell membrane and terminating in association with the envelope near one pole. part of each bundle demonstrated a herringbone-like periodicity (approximately 12-nm spacing). this structure was observed in cells from shake cultures and in gliding cells fixed by several methods. it is proposed that t ... | 1977 | 410797 |
| chromosome replication in myxococcus xanthus. | the rates of dna synthesis during the cell-division cycle were measured in myxococcus xanthus growing in three different media permitting a twofold variation in doubling time. in all three media, simple dna cycles were observed. synthesis of dna occurred during 85% of the cell-division cycle, independent of generation time, from 5 to 11 h. cells were observed to contain one bacterial nucleoid at birth that later divided synchronously midway through the cell cycle. nucleoid segregation appeared t ... | 1978 | 412830 |
| pigmentation phenotype instability in myxococcus xanthus. | cells of myxococcus xanthus fb2 produce tan or yellow colonies. subcultures of tan colonies yielded tan and yellow colonies and subcultures of most yellow colonies yielded only yellow colonies. strain fb2 variants in which the color type is more stable were obtained. yellow cells were distinguishable from tan by the presence of pigment(s) with an absorption maximum at 379 nm. fluctuation test experiments and the presence of this pigment(s) in liquid cultures of fb2 indicated that tan phenotype c ... | 1977 | 413617 |
| nutrition of myxococcus xanthus, a fruiting myxobacterium. | the minimal requirements for vegetative growth of myxococcus xanthus have been sought. isoleucine, leucine, and valine were required, and vitamin b12 was needed for the synthesis of methionine. pyruvate was an excellent energy source and an efficient source of cellular carbon. acetate, aspartate, glutamate, and most tricarboxylic acid cycle intermediates could also be utilized, but were less efficient sources of carbon and energy than was pyruvate. many mono- and disaccharides were tested, but, ... | 1978 | 415048 |
| fruiting-body formation and myxospore differentiation and germination in mxyococcus xanthus viewed by scanning electron microscopy. | streaming cells, fruiting bodies, and single cells undergoing myxospore differentiation and germination were examined in the fb strain of myxococcus xanthus by scanning electron microscopy. myxospores differentiated in fruiting bodies differed in size, in kinetics of germination, in the fate of the myxospore capsule, and in the external structure of the walls of newly emerged cells when compared with myxospores differentiated in liquid medium after glycerol induction. vegetative cells outgrowing ... | 1975 | 803486 |
| myxospore induction in a nondispersed growing mutant of myxococcus xanthus. | myxococcus xanthus rb5, a rough-colony-forming, nondispersed growing mutant of strain fbt, forms macroscopic, multicellular masses of radially oriented cells in shake cultures. the cells appear to be held together by slime fibrils. physical and enzymatic methods to disrupt the spheres were unsuccessful as were attempts to isolate dispersed growing mutants. during incubation of the spheres in starvation medium, the cells within convert to myxospores, indistinguishable from those formed in fruiti ... | 1975 | 804470 |
| cell surface modifications induced by calcium ion in the myxobacterium stigmatella aurantiaca. | calcium ion induces in the myxobacterium stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (d. f. gilmore and d. white, j. bacteriol. 161:113-117, 1985; b. j. womack, d. f. gilmore, and d. white, j. bacteriol. 171:6093-6096, 1989). the addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kda protein, and the accumulation in a low-speed centrifugal pellet of 10 polypepti ... | 1992 | 1522058 |
| proteins that rescue a-signal-defective mutants of myxococcus xanthus. | the asg mutants of myxococcus xanthus are defective in the production of an extracellular substance, called a-factor, that is required for expression of a set of fruiting body-specific genes. a-factor is released by wild-type cells (asg+) after 1 to 2 h of development. when a-factor is added to asg mutant cells, it restores expression of their a-factor-dependent genes. rescue of beta-galactosidase production in an asg mutant carrying the a-factor-dependent lacz transcriptional fusion (omega 4521 ... | 1992 | 1577696 |
| chloramphenicol resistance in myxococcus xanthus. | derivatives of myxococcus xanthus fb(t) resistant to chloramphenicol (25 mug/ml) arose spontaneously with a frequency of approximately 10(-7). one of these organisms (fb(t)cam(1) (r)) was characterized. fb(t)cam(1) (r) showed a unique type of phenotypic instability. after transfer from medium containing chloramphenicol to medium lacking the drug, resistance was lost after approximately one generation. the loss resulted in a sharp drop in the total number of chloramphenicol-resistant organisms an ... | 1975 | 806262 |
| on the evolution of the bacterial major sigma factors. | the existence of internal sequence homologies between the n-terminal halves of the gram-negative bacterial major sigma factors and their c-terminal halves, which correspond to minor factors, is reported. in the case of escherichia-salmonella sigma-70, an apparent homology was even found between the c-terminal helix-turn-helix dna-binding motif and the corresponding region of the peptide n half, which, however, is not directly engaged in promoter recognition. it is proposed that major sigma facto ... | 1992 | 1602496 |
| use of myxalin for improving vascular graft healing: evaluation of biocompatibility in rats. | myxalin is a glycopeptide extracted recently from a gram-negative bacterium. it has blood anticoagulant properties and can enhance endothelial cell growth. with the ultimate objective of using this bioactive molecule to promote vascular graft healing, this study assessed its biocompatibility in vivo by comparing the cellular and immunological responses of gelatin-coated knitted polyester grafts with and without myxalin following implantation in the peritoneal cavity of rats for prescheduled peri ... | 1992 | 1610738 |
| comparison of polysaccharides produced by myxococcus strains. | exopolysaccharides were prepared from cultures of four myxococcus strains grown on solid and in liquid media, and also from the fruiting bodies. lipopolysaccharides could be extracted with aqueous phenol from the vegetative bacteria, but were absent from microcysts. mannose and d-glucose were present in all the exopolysaccharides and three of the lipopolysaccharides examined. other monosaccharides identified in the exopolysaccharides were d-galactose, n-acetylglucosamine and n-acetylgalactosamin ... | 1975 | 807682 |
| [myxobacteria of the myxococcus family as indirect indicators of fecal matter in surface water. 1. communication (author's transl)]. | the fruiting-body-forming myxobacteria of the myxococcus order are coprophilic, i.e., they accumulate in biotopes that contain faecal substances. therefore, a special detection of myxococcus in water, based on the membrane-filter method, has been worked-out. field studies, undertaken in the region of a mechanico-biological clarifying plant, above a certain stretch of a stream (the regnitz) laden with waste-water, and on the bodensee (=lake constance) have revealed a clear correlation between the ... | 1975 | 808923 |
| coats from myxococcus xanthus: characterization and synthesis during myxospore differentiation. | an extracellular coat from glycerol-induced myxospores of myxococcus xanthus has been isolated and characterized. coats were examined chemically and by using both transmission and scanning electron microscopy. on a dry weight basis, approximately 75% of the coat is polysaccharide composed entirely of galactosamine and glucose. the remainder of the coat is protein (14%), glycine (8%), and organic phosphorus (less than 1%). coats remained morphologically intact despite boiling in 10 m urea, sodium ... | 1975 | 809426 |
| carbohydrate accumulation during myxospore formation in myxococcus xanthus. | during glycerol-induced myxospore formation in myxococcus xanthus, cellular neutral polysaccharide increases by approximately 200%, respiration decreases by 80%, and net phospholipid synthesis ceases. | 1975 | 811652 |
| bacteriophage mx-1: properties of the phage and its structural proteins. | bacteriophage mx-1 is a virulent dna phage for myxococcus. the host range includes strains of myxococcus xanthus, m. fulvus and m. virescens. the phage has a sedimentation coefficient (s degrees 20,w) of 1145s and a density of 1-531 g/ml. by using sds-polyacrylamide gel electrophoresis, 23 phage proteins with apparent mol. wt. between 10000 and 150000 were resolved. gel filtration in the presence of non-ionic detergent partially resolved the proteins. the fraction excluded from sephadex g-100, f ... | 1976 | 812957 |
| intercellular signaling in myxococcus development: the role of c factor. | cell communication governs differentiation and morphogenesis in fruiting body formation by myxococcus xanthus. transmission of a small short-range intercellular signal by a protein called c factor directs multicellular pattern formation and coordinates the timing of major developmental events. | 1991 | 1668187 |
| novel surface polymer changes in development of myxococcus spp. | | 1976 | 814464 |
| extrachromosomal dna in chloramphenicol resistant myxococcus strains. | the presence of extrachromosomal dna in strains of myxococcus xanthus and m fulvus was examined by rate-zonal centrifugation of radioactively-labelled dna in 'cleared lysates'. all the strains examined contained extrachromosomal dna, with the exception of m. xanthus fbt. chloramphenicol resistance is inducible in m. xanthus fbt. a peak of extrachromosomal dna, containing covalently closed molecules, was found in one of the induced strains, implying that induction of chloramphenicol resistance is ... | 1976 | 816990 |
| dna of myxococcus phage mx-1. pyrimidine isostichs and the recognition of a minor pyrimidine. | dna was isolated from bacteriophage mx-1 and was hydrolysed with acids. hydrolysis with 90% formic acid produced several interconvertable fluorescent artefacts. these substances were produced in greater quantity following hydrolysis with h2so4. in the course of the course of the study it was found that dna extracted from phage by 4-aminosalicylate and phenol contained 4-aminosalicylate and breakdown products derived from 4-aminosalicylate following acid hydrolysis. pyrimidine oligonucleotides re ... | 1976 | 821537 |
| the isolation and characterization of gliding motility mutants of myxococcus xanthus. | nonmotile and motility-altered mutants of myxococcus xanthus have been obtained by the use of chemical mutagens, ultraviolet irradiation, and a procedure for selective spontaneous mutants. as judged by their behaviour on a variety of growth media, in both plate and slide culture, the mutants were divided into four groups. one group contains mutants which are truly nonmotile. myxococcus xanthus nm, previously described as a nonmotile mutant, may be similar to type 3 mutants (described in text). | 1976 | 824040 |
| the amino acid sequence of nucleoside diphosphate kinase i from spinach leaves, as deduced from the cdna sequence. | the primary structure of nucleoside diphosphate (ndp) kinase from spinach leaves has been deduced from its cdna sequence. a lambda gt 11 cdna library derived from spinach leaves was screened using an antibody against ndp kinase i, which we previously purified to electrophoretic homogeneity (t. nomura, t. fukui, and a. ichikawa, 1991, biochim. biophys. acta 1077, 47-55). the cdna sequences of positive clones contained the amino acid coding region (444 base pairs) for ndp kinase i as well as 5' an ... | 1992 | 1322113 |
| a development-specific protein in myxococcus xanthus is associated with the extracellular fibrils. | we have been using monoclonal antibodies (mabs) as probes to study developmentally relevant cell surface antigens (csa) that may be required for cellular interactions in myxococcus xanthus. three independently isolated mabs, g69, g357, and g645, isolated by gill and dworkin recognize a csa detectable only on developing cells (j. s. gill and m. dworkin, j. bacteriol. 168:505-511, 1986). the csa is made within the first 30 min of submerged development and increases until myxosporulation. the csa i ... | 1991 | 1718941 |
| msdna and bacterial reverse transcriptase. | | 1991 | 1720608 |
| a transposition of the reverse transcriptase gene reveals unexpected structural homology to e. coli dna polymerase i. | the rational design of antiviral agents targeting the reverse transcriptase (rt) of the human immunodeficiency virus (hiv) would greatly benefit from a more intimate knowledge of the structure of rt. until now, the degree of sequence similarity between rt and e. coli dna polymerase i (pol i) has been thought to be confined to several small regions, suggesting little basis for homology molecular modeling. however, we have found that a region in the c terminal of the rt polymerase domain is homolo ... | 1991 | 1721884 |
| mutation and mapping of genes involved in production of the antibiotic ta in myxococcus xanthus. | transposition of tnv and tn5lac into myxococcus xanthus yielded 8,381 kanamycin-resistant mutants that were tested for antibiotic ta production. twenty-four of the mutants were nonproducers of ta (less than 0.4 ng/ml), and 3 produced a higher level (2.5 micrograms/ml) than the parent strain (1.5 micrograms/ml). for most of the strains, there was 100% cotransduction between kanamycin resistance and the altered ta phenotype. southern blot analysis of restriction digests of the mutant dna indicated ... | 1992 | 1332595 |
| characterization of the complex pdxh-tyrs operon of escherichia coli k-12 and pleiotropic phenotypes caused by pdxh insertion mutations. | we report the first molecular genetic analysis of a pyridoxine 5'-phosphate oxidase, the pdxh gene product of escherichia coli k-12. chromosomal insertions in and around pdxh were generated with various transposons, and the resulting phenotypes were characterized. the dna sequence of pdxh was determined, and the promoters of pdxh and the downstream gene tyrs, which encodes tyrosyl-trna synthetase, were mapped by rnase t2 protection assays of chromosomal transcripts. these combined approaches led ... | 1992 | 1356963 |
| effect of phosphate on antibiotic and extracellular protein production by myxococcus coralloides d. | the effect of inorganic phosphate concentrations on antibiotic and extracellular protein production by myxococcus coralloides d have been examined. antibiotic production by growing cells of this myxobacterium was maximal at phosphate concentrations of 10-20 mm, but was inhibited by concentrations higher than 20 mm. the total extracellular protein and the extracellular protein per cell ratio were independent of phosphate levels in the culture broth. | 1990 | 1367446 |
| sensory transduction in the gliding bacterium myxococcus xanthus. | sensory transduction in the gliding bacterium myxococcus xanthus is mediated by the frz genes. these genes are homologous to the chemotaxis genes of enteric bacteria and control the rate of cell reversal during gliding. sensory transduction is hypothesized to involve the recognition of substances present in the medium at the cell surface and the subsequent stimulation of a cytoplasmic methyl-accepting protein, frzcd. phosphorylation of frze is also involved in the sensory transduction pathway. d ... | 1991 | 1791749 |
| purification and properties of a new restriction endonuclease, mxai, from myxococcus xanthus f18e. | | 1990 | 1369313 |
| csga expression entrains myxococcus xanthus development. | the development cycle of the myxobacterium myxococcus xanthus consists of three partially overlapping morphological stages referred to as rippling, fruiting body formation, and sporulation, all of which are absent in csga null mutants. the csga gene product is an extracellular protein, referred to as the c signal, which is essential for developmental cell-cell interactions. csga expression increases throughout development, reaching its peak during sporulation. csga was made limiting for developm ... | 1992 | 1372277 |
| a-signalling and the cell density requirement for myxococcus xanthus development. | mutations in any of three asg (a-signalling) loci cause fruiting body development of myxococcus xanthus to arrest at about the 2-h stage. development can be restored to asg mutants by the addition of conditioned buffer in which wild-type cells have been developing or of a-factor purified from the conditioned buffer. two forms of a-factor have been identified: heat-stable a-factor, which is composed of amino acids and peptides, and heat-labile a-factor, which consists of at least two proteases. a ... | 1992 | 1429458 |
| control of cell density and pattern by intercellular signaling in myxococcus development. | myxococcus xanthus cells feed, move, and develop cooperatively. genetic, biochemical, and cell mosaic studies demonstrate that cells coordinate their multicellular behavior by transmission of intercellular signals. starvation for amino acids at sufficiently high density on a solid surface initiates a series of events culminating in the formation of a multicellular structure called a fruiting body filled with dormant, environmentally resistant spores. this review discusses how myxobacteria use ex ... | 1992 | 1444251 |
| use of tn5lac to study expression of genes required for production of the antibiotic ta. | the beta-galactosidase activities arising from tn5lac insertions in several genes required for antibiotic ta production were measured under different growth conditions. in all of the non-ta-producing mutants, the beta-galactosidase specific activity was higher when the cells were grown in nutrient-limited 0.5cts medium (0.5% casitone plus alanine, serine, and glucose) than in rich 2ct medium (2% casitone). one of the mutants, 420, had low beta-galactosidase specific activity in both media. the o ... | 1992 | 1444312 |
| sporulation in prokaryotes and lower eukaryotes. | during the past year, highlights in sporulation research include the demonstration that phosphorylation of spooa is a critical factor in bacillus subtilis development; the identification of c alpha proteins, adenylyl cyclase and protein kinase a genes in dictyostelium; proof that an endogenous antisense rna regulates gene expression in dictyostelium; and characterization of a second type of differentiated cell in myxococcus. | 1992 | 1458028 |
| a unique repetitive dna sequence in the myxococcus xanthus genome. | we found a novel type of repetitive dna sequence in the myxococcus xanthus genome. the first repetitive sequence is located in the spacer region between the ops and tps genes. we cloned five other repetitive sequences using the first repetitive sequence as a probe and determined their nucleotide sequences. comparison of these sequences revealed that the repetitive sequences consist of a 87-bp core sequence and that some clones share additional homology on their flanking regions. | 1991 | 1900509 |
| myxococcus xanthus protein c is a major spore surface protein. | fruiting body formation in myxococcus xanthus involves the aggregation of cells to form mounds and the differentiation of rod-shaped cells into spherical myxospores. the surface of the myxospore is composed of several sodium dodecyl sulfate (sds)-soluble proteins, the best characterized of which is protein s (mr, 19,000). we have identified a new major spore surface protein called protein c (mr, 30,000). protein c is not present in extracts of vegetative cells but appears in extracts of developi ... | 1991 | 1900510 |
| determinants of an unusually stable mrna in the bacterium myxococcus xanthus. | myxococcus xanthus is a gram-negative bacterium which has a complex life cycle that includes development (fruiting body formation). the gene for myxobacterial haemagglutinin, mbha, is developmentally regulated and highly expressed. in this report we show that the mbha mrna is exceptionally stable for a prokaryotic organism, exhibiting a chemical half life (t1/2) of 150 min at 18 h of development. the mbha mrna was not stable in vegetatively growing cells nor was it stable when expressed in esche ... | 1992 | 1479889 |