Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| interference reflection microscopic study of sites of association between gliding bacteria and glass substrata. | sites of close contact between gliding cytophaga sp. strain u67 cells and glass were examined by interference reflection microscopy. site patterns changed during translocation and moved relative to the substratum, in contrast to previous interference reflection microscopy observations of fibroblast and amoeboid motility. sinistral rotation around the long axis of the cell was coupled with gliding, except when curved cells traversed curvilinear pathways. close contact was temporary, since cells f ... | 1989 | 2768185 |
| expression of many developmentally regulated genes in myxococcus depends on a sequence of cell interactions. | certain developmental mutants of myxococcus xanthus can be complemented extracellularly by wild-type cells. these mutants behave as if they are defective in cell-cell interactions that are required for development. there may be several different interactions because the mutants belong to four extracellular complementation groups (a, b, c, and d). we report here that b- and c- mutations change the pattern of gene expression during myxococcus development as detected by transcriptional fusions to l ... | 1987 | 2828174 |
| mode of insertion of the broad-host-range plasmid rp4 and its derivatives into the chromosome of myxococcus xanthus. | the mode of insertion of the broad-host-range plasmid rp4 into the chromosome of myxococcus xanthus strain dz1 has been analyzed. the plasmid integrated in numerous sites of the chromosome and generated insertional mutations. there is a hot spot of integration located between 31.5 and 34.5 kb clockwise from the ecori site of the plasmid. in the absence of this segment the insertion can, however, take place, but much less efficiently. the presence of transposable elements on the plasmid decreases ... | 1987 | 2829249 |
| use of recombination techniques to examine the structure of the csg locus of myxococcus xanthus. | the myxobacteria are among the simplest organisms with a developmental cycle that is dependent on cell cooperation, and they provide an outstanding system with which to study genes involved in cell interactions. myxococcus xanthus cells which acquire a csg mutation (formerly known as spoc) lose three different traits, the ability to sporulate, the ability to stimulate adjacent csg cells to sporulate, and the ability to ripple. the boundaries of the csg locus were determined by transferring a rec ... | 1988 | 2830469 |
| comparison of the phosphatases of lysobacter enzymogenes with those of related bacteria. | lysobacter enzymogenes atcc 29487 (uasm 495) produces an outer-membrane-associated phosphatase and an excreted phosphatase. the cell-associated enzyme was compared to phosphatases of nine other gram-negative gliding bacteria and to that of escherichia coli. the other three species of the genus lysobacter also produce a particulate, cell-associated phosphatase. antiserum prepared against the phosphatase from the outer membrane of l. enzymogenes effectively precipitated the phosphatases of two oth ... | 1987 | 2833562 |
| tn5-mediated transposition of plasmid dna after transduction to myxococcus xanthus. | after coliphage p1-mediated transfer of tn5-containing plasmid dna from escherichia coli to myxococcus xanthus, transductants were identified which contained plasmid sequences integrated at many sites on the bacterial chromosome. the unaltered plasmid dna sequences in these transductants were apparently flanked by intact tn5 or is50 sequences. these results suggest that tn5-mediated transposition has occurred and provide a method for integrating plasmid dna into the m. xanthus chromosome without ... | 1988 | 2844730 |
| genetic identification and cloning of a gene required for developmental cell interactions in myxococcus xanthus. | developmental mutants of myxococcus xanthus have been previously described which appear to be defective in required cell-cell interactions. these mutants fall into four phenotypic classes, asg, bsg, csg, and dsg, each of which is unable to differentiate into spores but can be rescued by extracellular complementation by wild-type cells or by mutants of a different class. we report the identification of one of the loci in which mutations result in a bsg phenotype. the cloned locus was contained on ... | 1988 | 2846514 |
| identification and characterization of the myxococcus xanthus bsga gene product. | the bsga mutants of myxococcus xanthus are blocked at a very early stage of the developmental program. they fail to produce fruiting bodies or to sporulate under normal conditions but can be rescued by extracellular complementation in mixtures with wild-type cells. a bsga-lacz gene fusion was constructed and expressed in escherichia coli. the resulting fusion protein, which has beta-galactosidase enzyme activity, was partially purified by affinity chromatography and preparative polyacrylamide ge ... | 1988 | 2846515 |
| utilization of incp-1 plasmids as vectors for transposon mutagenesis in myxobacteria. | no free plasmid has ever been found in the myxobacterium myxococcus xanthus, but incp-1 plasmids are able to integrate into the chromosome of this bacterium. the frequency of integration depends greatly upon the structure of the incp-1 plasmid used. this property has been used to devise new delivery systems for transposon mutagenesis in this species. plasmids with low integration efficiencies have proved to be efficient donors of tn5, while plasmids with very high frequencies of integration coul ... | 1988 | 2855525 |
| correlation of energy-dependent cell cohesion with social motility in myxococcus xanthus. | an agglutination assay was used to study cell cohesion in the myxobacterium myxococcus xanthus. vegetative cells agglutinated in the presence of the divalent cations mg2+ and ca2+. agglutination was blocked by energy poisons that inhibit electron transport, uncouple oxidative phosphorylation, or inhibit the membrane-bound atpase. however, energy was not required for the maintenance of cells in the multicellular aggregate. cyanide, a strong inhibitor of agglutination, did not cause cells to disso ... | 1986 | 2940231 |
| cloning and complementation analysis of the "frizzy" genes of myxococcus xanthus. | fruiting-body formation in myxococcus xanthus involves the aggregation of cells into raised mounds, where they sporulate. "frizzy" mutants fail to aggregate into mounds, but rather aggregate into "frizzy" filaments (d.r. zusman 1982). the frizzy mutations (frz) were found to be genetically linked. the region of dna carrying the frz genes was cloned in escherichia coli by selecting for the kanamycin resistance element present on a transposon tn5 insertion linked to the frz genes. phage p1 mediate ... | 1985 | 2984519 |
| physical characterization of the genome of the myxococcus xanthus bacteriophage mx-8. | we have constructed a restriction map for the genome of bacteriophage mx-8 from myxococcus xanthus using the enzymes pvuii, mboi, and ecori. the phage genome size, as determined by restriction analysis, is 51.7 +/- 0.6 kb. double digestions, redigestions of isolated fragments, and crossed-contact hybridization of partial digestion products show that the restriction map is circular. restriction analysis and southern hybridization show that the phage dna molecules are packaged sequentially from a ... | 1985 | 2987644 |
| functional complementation between the two homologous genes, ops and tps, during differentiation of myxococcus xanthus. | protein s is a development-specific protein of myxococcus xanthus encoded by the tps gene. it has been shown that there are two extensively homologous genes (ops and tps) tandemly repeated in the same direction with a 1.4 kb spacer fragment between them (inouye et al. 1983). seven deletion mutants were constructed by removing the ops gene, the tps gene, segments of the spacer sequence or combinations of these regions. the deleted regions were replaced with dna fragments carrying the tn5 gene for ... | 1985 | 2993793 |
| novel one-step cloning vector with a transposable element: application to the myxococcus xanthus genome. | a new strategy was developed for rapid cloning of genes with a transposon mutation library. we constructed a transposon designated tnv that was derived from tn5 and consists of the gene coding for neomycin phosphotransferase ii as well as the replication origin of an escherichia coli plasmid, psc101, flanked by tn5 inverted repeats (is50l and is50r). tnv can transpose to many different sites of dna in e. coli and myxococcus xanthus and confers kanamycin resistance (kmr) to the cells. from the km ... | 1985 | 2995310 |
| transposon tagging to detect a latent virus in myxococcus xanthus. | transposon mutagenesis of the bacterium myxococcus xanthus with the transposon tn5 revealed a special class of bacterial mutants that transduced the transposon through culture supernatant fluids. virus-like particles copurified with transducing activity. transposon tagging for detecting these virus-like particles may be generally useful in isolating endogenous viral agents capable of transferring genetic information between cells. | 1985 | 2996138 |
| cell interactions govern the temporal pattern of myxococcus development. | 1985 | 3007019 | |
| analysis of the products of the myxococcus xanthus frz genes. | the frizzy (frz) genes of myxococcus xanthus control the ability of cells to reverse direction of gliding motility. the orientation of the frz genes was studied by isolating transcriptional fusions with the transposon derivative tn5-lac. the frz genes were then cloned in the proper orientation in an expression vector. by using maxicell experiments, we were able to identify several labeled bands which were plasmid encoded. to identify the labeled proteins and their respective genes, we constructe ... | 1986 | 3009422 |
| role of cell cohesion in myxococcus xanthus fruiting body formation. | dsp mutants of myxococcus xanthus have a complex phenotype with abnormal cell cohesion, social motility, and development. all three defects are the result of a single mutation in the dsp locus, a region of dna about 14 kilobases long. cohesion appears to play a central role in social motility, since nonsocial mutants exhibit weak agglutination or, in the case of dsp cells, no agglutination (l. j. shimkets, j. bacteriol. 166:837-841, 1986). however, dsp cells can be agglutinated by cohesive strai ... | 1986 | 3011748 |
| a global analysis of developmentally regulated genes in myxococcus xanthus. | tn5 lac is a transposon that fuses the transcription of lacz to exogenous promoters. we generated 2374 tn5 lac insertion-containing strains of myxococcus xanthus, a soil bacterium that undergoes multicellular development which culminates in the formation of spores. thirty-six strains were identified that specifically increase beta-galactosidase expression at some particular time during development and these expression times range from minutes after starvation initiates development to 24 hr, when ... | 1986 | 3017794 |
| intercellular signaling is required for developmental gene expression in myxococcus xanthus. | certain developmental mutants of myxococcus xanthus can be complemented (extracellularly) by wild-type cells. insertions of tn5 lac (a transposon which couples beta-galactosidase expression to exogenous promoters) into developmentally regulated genes were used to investigate extracellular complementation of the a group mutations. a- mutations reduced developmental beta-galactosidase expression from 18 of 21 tn5 lac insertions tested and that expression was restored to a- tn5 lac cells by adding ... | 1986 | 3017795 |
| control of multicellular development: dictyostelium and myxococcus. | 1986 | 3028248 | |
| cloning of the gene for myxobacterial hemagglutinin and isolation and analysis of structural gene mutations. | myxobacterial hemagglutinin (mbha) is a major developmentally induced protein that accumulates during the period of cellular aggregation in the bacterium myxococcus xanthus. it has been shown that this lectin is targeted to the cell surface and periplasmic space of developmental cells, suggesting that it may play a role in cell-cell recognition or agglutination. we have cloned the structural gene for mbha by using synthetic deoxyoligonucleotides containing sequences deduced from the amino acid s ... | 1987 | 3038850 |
| determination of bacterial ammonia pools using myxococcus virescens as an example. | samples (150 microliters) from liquid cultures of known cell density of myxococcus virescens (myxobacterales) were used for the determination of the intracellular nh3/nh+4 concentrations (= total ammonia). the cells were separated from the culture broth within 30 s by centrifugation through a silicone layer and were lysed immediately with 20 microliters of a disintegration liquid at the bottom of the centrifugation tube. the ammonia concentrations of the lysates were determined with a dohrmann n ... | 1986 | 3082243 |
| myxococcus xanthus autocide ami. | autocide ami of myxococcus xanthus was purified and shown to be a mixture of fatty acids: 46.4% saturated, 49.3% monounsaturated, and 4.3% diunsaturated. the specific autocidal activities (units per milligram) were as follows: purified ami, 1,000; saturated fraction, 100; monounsaturated fraction, 800; diunsaturated fraction, 2,200. model fatty acids mimicked to some extent the activity of ami, although none of the fatty acids tested were as active as purified ami. spontaneous and induced mutant ... | 1986 | 3087961 |
| genetic analysis of myxococcus xanthus and isolation of gene replacements after transduction under conditions of limited homology. | genetic analysis of myxococcus xanthus is greatly facilitated by the ability to introduce cloned dna into m. xanthus to generate gene replacement and merodiploid strains. however, gene replacement strains are difficult to obtain when the region(s) of homology between the cloned dna and the m. xanthus chromosome is limited (less than 1 kilobase). we found that gene replacements can be obtained at an increased frequency by a two-step procedure involving the use of bacteriophage p1 to isolate merod ... | 1986 | 3090023 |
| nucleotide sequence of the myxobacterial hemagglutinin gene contains four homologous domains. | myxococcus xanthus, a gram-negative bacterium, has a complex life cycle that includes fruiting-body formation, a primitive form of multicellular development. myxobacterial hemagglutinin (mbha) is a lectin that is induced during the aggregation phase of fruiting-body formation. we have cloned the gene for mbha and determined its sequence by the dideoxy chain-termination technique. the sequence data show the probable sites for translational initiation and termination and suggest that mbha does not ... | 1986 | 3092212 |
| control of developmental gene expression by cell-to-cell interactions in myxococcus xanthus. | the ssba mutants of myxococcus xanthus behave as if they are unable to produce a cell-to-cell signal required for normal development. they are unable to form fruiting bodies or spores on developmental medium. they do sporulate, however, if allowed to develop in mixtures with wild-type cells. fusions of developmentally induced promoters of m. xanthus to the escherichia coli lacz gene were used to characterize the effect of the ssba mutations on developmental gene expression. each of the five inde ... | 1986 | 3093463 |
| cell surface antigens during submerged development of myxococcus xanthus examined with monoclonal antibodies. | eighteen monoclonal antibodies directed against cell surface antigens of myxococcus xanthus were followed by enzyme-linked immunosorbent assay. three of the monoclonal antibodies were specifically directed against antigens present only on cells undergoing fruiting body development. these cell surface antigens became detectable by the early preaggregation stage (2 to 4 h) of development and increased until early aggregation (9 to 10 h), after which the concentrations of two of the cell surface an ... | 1986 | 3096957 |
| heat shock proteins of vegetative and fruiting myxococcus xanthus cells. | the heat shock response of myxococcus xanthus was investigated and characterized. when shifted from 28 to 40 degrees c, log-phase cells rapidly ceased growth, exhibited a 50% reduction in cfu, and initiated the synthesis of heat shock proteins (htps). heat-shocked log-phase m. xanthus cells labeled with [35s]methionine were found to produce 18 major htps. the htps, analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, were characterized with regard to molecular ... | 1986 | 3096968 |
| cell-density-dependent killing of myxococcus xanthus by autocide amv. | autocide amv of myxococcus xanthus was purified and identified as phosphatidylethanolamine. alkaline hydrolysis of amv yielded a high proportion of mono- and diunsaturated fatty acids. the bactericidal activity of amv on m. xanthus depended upon the density of target cells: the greater the cell density, the greater the killing by amv. for example, at 2 u of amv per ml, 0, 50, and 99% killing was measured with 2 x 10(4), 2 x 10(5), and 2 x 10(7) target cells per ml, respectively. the cell-density ... | 1987 | 3100506 |
| control of morphogenesis in myxobacteria. | the myxobacteria are gram-negative soil bacteria that live in large communities known as swarms. the most remarkable characteristic of myxobacteria is their ability to form fruiting bodies that have a species-specific shape and color. fruiting body formation requires the concerted effort of hundreds of thousands of cells. development is initiated only when two conditions are satisfied. the cells must be nutritionally deprived (environmental signal) and there must be many other cells in the vicin ... | 1987 | 3107905 |
| cloning of the gene for protein s: a development-specific ca2+-binding protein from myxococcus xanthus. | 1987 | 3108625 | |
| induction, purification and some properties of phage tail-like particles from myxococcus coralloides d. | myxococcus coralloides d was lysogenic for a defective prophage. the particles of the defective bacteriophage could be induced by ultraviolet light and mitomycin c, but the particles did not appear in the supernatants, unless the cells were lysed with chloroform. the phage tails were purified by using a two-phase separation method, ultracentrifugation, chromatography through sepharose 4b, treatment with chloroform, dialysis and centrifugation on a sucrose gradient. the chemical analysis of the p ... | 1987 | 3108629 |
| inhibition of development in myxococcus xanthus by monoclonal antibody 1604. | monoclonal antibody (mab) 1604 is directed against a cell surface antigen of myxococcus xanthus. purified antibody 1604 inhibited development of m. xanthus under conditions of submerged culture procedure otherwise leading to fruiting body formation. intact molecules of mab 1604, as well as its fab fragments, inhibited developmental aggregation, autolysis, fruiting body formation, and sporulation. the addition of relatively small amounts of antibody every 4 hr was much more effective than a singl ... | 1987 | 3110769 |
| characterization of calcium-binding sites in development-specific protein s of myxococcus xanthus using site-specific mutagenesis. | protein s, the most abundant protein synthesized during development of the gram-negative bacterium myxococcus xanthus, assembles on the surface of the spores. it can be dissociated from the spores using divalent metal chelators and will reassemble on the spores in the presence of calcium. the amino acid sequence of protein s contains regions which have homology to the calcium-binding sites of calmodulin. protein s was found to bind 2 mol of calcium/mol of protein with kd values of 27 and 76 micr ... | 1988 | 3121626 |
| the simple repeat poly(dt-dg).poly(dc-da) common to eukaryotes is absent from eubacteria and archaebacteria and rare in protozoans. | genomic dna from a wide variety of prokaryotic and eukaryotic organisms has been assayed for the simple repeat sequence poly(dt-dg).poly(dc-da) by southern blotting and dna slot blot hybridizations. consistent with findings of others, we have found the simple alternating sequence to be present in multiple copies in all organisms in the animal kingdom (e.g., mammals, reptiles, amphibians, fish, crustaceans, insects, jellyfish, nematodes). the tg element was also found in lower eukaryotes (sacchar ... | 1986 | 3127653 |
| novel macrocyclic antibiotics: megovalicins a, b, c, d, g and h. i. screening of antibiotics-producing myxobacteria and production of megovalicins. | new antibiotics belonging to macrocyclic were discovered and named megovalicins a, b, c, d, g and h. the antibiotics were accumulated endogeneously by a newly isolated myxobacterium identified as myxococcus flavescens. tank culture of the bacterium for 4 days gave 8.8 g cells/liter on a wet basis, and 4.8, 7.1, 20.0, 0.4, 3.75 and 15.0 micrograms of megovalicins a, b, c, d, g and h respectively were obtained from 1 g wet cells. | 1988 | 3131289 |
| novel macrocyclic antibiotics: megovalicins a, b, c, d, g and h. ii. isolation and chemical structures of megovalicins. | myxococcus flavescens aj12298 was found to produce the complex of macrocyclic antibiotics named megovalicins. the physico-chemical studies revealed that megovalicins c and b were identical to myxovirescin a1 and antibiotic m-230b, respectively, and that megovalicins a, d, g and h were closely related new antibiotics. | 1988 | 3131290 |
| reexamination of the role of autolysis in the development of myxococcus xanthus. | it has been widely reported that 80 to 90% of the cell population undergoes autolysis during sporulation in myxococcus xanthus. a re-evaluation of the techniques used to measure autolysis in m. xanthus showed that the methods previously used to draw this conclusion are subject to artifacts, which result in a substantial underestimation of the number of cells present during development. we found that at least 80% of the cells that enter development survive throughout fruiting body formation. the ... | 1988 | 3137213 |
| localization of the cis-acting regulatory dna sequences of the myxococcus xanthus tps and ops genes. | the cis-acting regulatory regions of the tps and ops genes of myxococcus xanthus were localized by analyzing the expression of fusions of these genes with the lacz gene. a 201-base-pair (bp) fragment of tps dna extending 95 bp upstream (-95) from the transcriptional start was sufficient to direct developmentally regulated expression of fusion gene activity. the segment of tps dna between -95 and -81 contained information necessary for developmental regulation. a segment of ops dna extending upst ... | 1988 | 3139640 |
| acceleration of starvation- and glycerol-induced myxospore formation by prior heat shock in myxococcus xanthus. | the effect of heat shock on myxococcus xanthus was investigated during both glycerol- and starvation-induced development. cells heat shocked at 40 degrees c for 1 h prior to a development-inducing signal displayed an accelerated rate of myxospore formation at 30 degrees c. additionally, m. xanthus cells heat shocked prior to glycerol induction formed a greater total number of myxospores when sporulation was complete than did control cells maintained at 30 degrees c. however, in starvation-induce ... | 1988 | 3141380 |
| an extracellular blood-anticoagulant glycopeptide produced exclusively during vegetative growth by myxococcus xanthus and other myxobacteria is not co-regulated with other extracellular macromolecules. | we have shown that the blood anticoagulant activity (baa) secreted by myxococcus xanthus (designated myxaline) is a heat-stable molecule; a high-molecular-mass extracellular fraction also with an apparent baa is a thermolabile protease. this property allowed us to assay the baa content in crude boiled culture supernatants and to study the conditions under which it is produced. heat-stable baa is strictly extracellular and its production is restricted to vegetative growth in m. xanthus. unlike th ... | 1988 | 3141577 |
| site-specific integration and expression of a developmental promoter in myxococcus xanthus. | a series of intercellular signals are involved in the regulation of gene expression during fruiting body formation of myxococcus xanthus. mutations which block cell interactions, such as csga (formerly known as spoc), also prevent expression of certain developmentally regulated promoters. csga+ cells containing tn5 lac omega dk4435, a developmentally regulated promoter fused to lacz, began synthesizing lacz mrna 12 to 18 h into the developmental cycle. beta-galactosidase specific activity increa ... | 1988 | 3142850 |
| inhibition of cell-cell interactions in myxococcus xanthus by congo red. | the function of molecules associated with the cell surface may be determined by examining the phenotype of cells treated with inhibitors specific to these cell surface molecules. this strategy was used to examine the function of the major congo red receptor of the myxobacterium myxococcus xanthus, which has a developmental cycle that involves social interactions among cells. a class of social motility mutations (a+ s-), known as dsp, may inhibit the same subcellular component as congo red becaus ... | 1988 | 3142856 |
| cell surface properties correlated with cohesion in myxococcus xanthus. | the gliding behavior of myxococcus xanthus cells is controlled by two multigene systems, a and s, which encode information for adventurous and social behaviors, respectively. the s system can be genetically disrupted through mutation, such as a dsp mutation, or phenotypically disrupted by treating cells with the diazo dye congo red (arnold and shimkets, j. bacteriol. 170:5765-5770, 1988). one of the functions controlled by the s system is cell agglutination. immediately after the induction of ag ... | 1988 | 3142857 |
| isolation of additional monoclonal antibodies directed against cell surface antigens of myxococcus xanthus cells undergoing submerged development. | thirteen additional monoclonal antibodies directed against cell surface antigens of myxococcus xanthus cells undergoing submerged development were isolated and partially characterized. as measured by quantitative enzyme-linked immunosorbent assay, 10 of these antibodies recognized antigens common to both vegetatively growing cells and cells undergoing submerged development; 3 antibodies recognized antigens specific to developing cells. five antigens were revealed as single bands on western blots ... | 1988 | 3142865 |
| a link between cell movement and gene expression argues that motility is required for cell-cell signaling during fruiting body development. | nonmotile mutants of myxococcus xanthus (myxobacterales) failed to execute the morphogenetic movements required to shape a fruiting body. in addition, nonmotile mutants produced very few spores when plated for fruiting body development at cell densities appropriate for wild-type cells. at higher initial cell densities, the proportion of nonmotile cells that sporulate increased, indicating that one important function of motility in fruiting body development is to increase the local cell density. ... | 1988 | 3145903 |
| antibiotic ta--a new adherent agent for the treatment of periodontal disease. | 1988 | 3271636 | |
| identification of a vegetative promoter in myxococcus xanthus. a protein that has homology to histones. | a physical map of 330 x 10(3) base-pairs near the replication origin of myxococcus xanthus chromosome has been established already. using dna fragments from this region, northern blot hybridization analysis was carried out in order to identify the genes expressed during vegetative growth. one of the genes, tentatively designated as vega, was cloned and its entire dna sequence was determined. the amino acid sequence of the gene product deduced from the dna sequence reveals that the vega protein i ... | 1987 | 3316662 |
| a bacterial calcium-binding protein homologous to calmodulin. | many of the effects of calcium ions in eukaryotic cells are mediated by calcium-binding regulatory proteins such as calmodulin, in which each calcium-binding site has a distinctive helix-loop-helix conformation termed the ef hand. protein s from the spore coat of the gram-negative bacterium myxococcus xanthus has been shown to resemble calmodulin in its internally-duplicated structure and ability to bind calcium. however, it has a beta-sheet secondary structure rather than the helix-loop-helix a ... | 1987 | 3627246 |
| isolation of a surface glycoprotein from myxococcus xanthus. | the isolation of a glycoprotein from vegetative cells of myxococcus xanthus is reported. the protein, abbreviated vgp, was first identified during a survey of surface proteins as a major protein that could be radioiodinated in vegetative, but not developing, cells (p.y. maeba, j. bacteriol. 155:1033-1041, 1983). the protein was extracted from membranes with triton x-100 and subsequently purified by deae-cellulose chromatography, chromatofocusing, and gel filtration. the protein has an mr of appr ... | 1986 | 3700339 |
| transfer of plasmid rp4 to myxococcus xanthus and evidence for its integration into the chromosome. | the broad-host-range plasmid rp4 and its derivative r68.45 were transferred to myxococcus xanthus dk101 and dz1; rp4 was maintained integrated in the chromosome. loss of plasmid markers occurred during the growth of the transconjugants, which could be prevented by selective pressure with oxytetracycline. the integrated plasmid was transferred back to escherichia coli often as rp4-prime plasmids carrying various segments of the m. xanthus chromosome. it also mediated chromosomal transfer between ... | 1985 | 3918015 |
| differential expression of protein s genes during myxococcus xanthus development. | protein s, the most abundant protein synthesized during development of the fruiting bacterium myxococcus xanthus, is coded by two highly homologous genes called protein s gene 1 (ops) and protein s gene 2 (tps). the expression of these genes was studied with fusions of the protein s genes to the lacz gene of escherichia coli. the gene fusions were constructed so that expression of beta-galactosidase activity was dependent on protein s gene regulatory sequences. both the gene 1-lacz fusion and th ... | 1985 | 3918984 |
| physical mapping of a 330 x 10(3)-base-pair region of the myxococcus xanthus chromosome that is preferentially labeled during spore germination. | myxococcus xanthus was pulse-labeled with [3h]thymidine immediately after germination of dimethyl sulfoxide-induced spores. the restriction enzyme digests of the total chromosomal dna from the pulse-labeled cells were analyzed by one-dimensional as well as two-dimensional agarose gel electrophoresis. four psti fragments preferentially labeled at a very early stage of germination were cloned into the unique psti site of pbr322. by using these clones as probes, a restriction enzyme map was establi ... | 1985 | 3920197 |
| monoclonal antibodies against cell-surface antigens of developing cells of myxococcus xanthus. | monoclonal antibodies (mca) have been developed against cell surface antigens (csa) of myxococcus xanthus undergoing fruiting body formation. three of these antibodies are directed against csa which increase during development, six against csa which decrease and three against csa which show no change during development. western-type immunoblots have been done to determine the molecular weights of the csa to which the various mca bind. various applications of these mca to the study of myxobacteri ... | 1985 | 3923899 |
| two homologous genes coding for spore-specific proteins are expressed at different times during development of myxococcus xanthus. | the ops and tps genes of myxococcus xanthus have ca. 90% dna and amino acid sequence homology and are in the same orientation separated by a spacer region of only 1.4 kilobases. the products of the two genes were found to cross-react immunologically, and both were capable of ca2+-dependent self-assembly on the surface of myxospores. however, the ops and tps genes were expressed very differently during the developmental cycle of m. xanthus. the tps gene is induced early during fruiting body forma ... | 1985 | 3924890 |
| myxococcus xanthus spore coat protein s may have a similar structure to vertebrate lens beta gamma-crystallins. | the gram-negative bacterium myxococcus xanthus has a complex life cycle during which large amounts of a protein of relative molecular mass (mr) 19,000, known as protein s, are assembled into a spore surface coat by a process that specifically requires calcium ions. the gene for protein s has been cloned and the dna sequence shows that the gene product is composed of four internally repeated homologous sequences, each 40 amino acids long. although protein s resembles calmodulin both in its intern ... | 1985 | 3925350 |
| in vitro synthesis of c15-c60 polyprenols in a cell-free system of myxococcus fulvus and determination of chain length by high-performance liquid chromatography. | 1985 | 3927113 | |
| cell interactions in myxobacterial growth and development. | during their complex life cycle, myxobacteria manifest a number of cell interactions. these include contact-mediated interactions as well as those mediated by soluble extracellular signals. some of these interactions are well-defined; in addition, the tools for molecular and genetic analysis of these interactions in myxococcus xanthus are now available. | 1985 | 3929384 |
| cell-cell interactions in developmental lysis of myxococcus xanthus. | the developmental events of sporulation and fruiting body formation in the prokaryote myxococcus xanthus are preceded by a stage of massive cell death. two phenotypically complementable strains of m. xanthus defective in developmental lysis were identified from a group of conditional sporulation mutants. mixture of the two lysis groups resulted in full complementation of lysis, sporulation, and fruiting body formation; efficient sporulation was observed only in strain mixtures where lysis was co ... | 1985 | 3932110 |
| methylation of macromolecules during development in myxococcus xanthus. | covalent modification of macromolecules can serve to alter their biological activities and is therefore frequently involved in regulation. i examined methylation of proteins and carbohydrates during development and vegetative growth in the procaryote myxococcus xanthus. striking differences in the patterns of protein methylation occurred when cell development was induced by nutrient deprivation on solid media and when cells were starved in liquid. in addition, a methylated, protease-resistant ma ... | 1985 | 3932324 |
| distribution of multicopy single-stranded dna among myxobacteria and related species. | multicopy single-stranded dna (msdna) is a short single-stranded linear dna originally discovered in myxococcus xanthus and subsequently found in stigmatella aurantiaca. it exists at an estimated 500 to 700 copies per chromosome (t. yee, t. furuichi, s. inouye, and m. inouye, cell 38:203-209, 1984). we found msdna in other myxobacteria, including myxococcus coralloides, cystobacter violaceus, cystobacter ferrugineus (cbfe17), nannocystis exedens, and nine independently isolated strains of m. xan ... | 1985 | 3932332 |
| immunomodulation by myxospores of myxococcus xanthus. | glycerol-induced myxospores of myxococcus xanthus caused non-specific modulation of humoral and cellular immune responses in laboratory animals. the number of cells which formed specific haemolysins in spleens of mice immunized with sheep erythrocytes was increased when 0.5 x 10(8) myxospores were inoculated 2 d after the erythrocytes, and decreased when myxospores were injected 2 d before or at the same time as the erythrocytes. both the igg primary response and the secondary response to erythr ... | 1985 | 3932594 |
| adsorption of antibiotic ta to dental hard tissues. | antibiotic ta (ta) is a wide-spectrum, bactericidal antibiotic produced by myxococcus xanthus strain ta. it was previously demonstrated that ta binds tightly to soft tissues while retaining its bactericidal activity in the bound form. the present study was undertaken to investigate ta adsorption to dental hard tissues. slabs of dental tissues that had been cut from periodontally-involved extracted human teeth were treated with ta and then washed in saline with shaking (saline being replaced ever ... | 1985 | 3935702 |
| "frizzy" genes of myxococcus xanthus are involved in control of frequency of reversal of gliding motility. | myxococcus xanthus, a gram-negative bacterium, has a complex life cycle that includes fruiting body formation. frizzy (frz) mutants are unable to aggregate normally, instead forming frizzy filamentous aggregates. we have found that these mutants are defective in the control of cell reversal during gliding motility. wild-type cells reverse their direction of gliding about every 6.8 min; net movement occurs since the interval between reversals can vary widely. the frza-c, -e and -f mutants reverse ... | 1985 | 3936045 |
| induction of morphogenesis by methionine starvation in myxococcus xanthus: polyamine control. | the induction of mycrocyst formation by methionine starvation was demonstrated in myxococcus xanthus by several methods. growing in a defined medium (m(1)), m. xanthus had a doubling time of 6.5 hr. four amino acids-leucine, isoleucine, valine, and glycine-were required for growth under these conditions. when the concentration of several amino acids in the medium was reduced (m(2)), the doubling time increased to 10 to 12 hr, and a requirement for methionine was observed. methionine starvation l ... | 1970 | 4097531 |
| xanthacin. a bacteriocin of myxococcus xanthus fb. | 1974 | 4132608 | |
| surface structure of gliding bacteria after freeze-etching. | ultrastructural studies of gliding bacteria demonstrate 10- to 11-nm beads on the inner surface of the outer bilayer of cytophaga columnaris. these were not found in myxococcus xanthus. on treatment with glutaraldehyde and ethanol, the beads appear in linear arrays. | 1973 | 4197273 |
| fatty acids of myxococcus xanthus. | fatty acids were extracted from saponified vegetative cells and myxospores of myxococcus xanthus and examined as the methyl esters by gas-liquid chromatography. the acids consisted mainly of c(14) to c(17) species. branched acids predominated, and iso-pentadecanoic acid constituted half or more of the mixture. the other leading component (11-28%) was found to be 11-n-hexadecenoic acid. among the unsaturated acids were two diunsaturated ones, an n-hexadecadienoic acid and an iso-heptadecadienoic ... | 1973 | 4197903 |
| studies on antiviral property of fruiting myxobacteria (myxococcus virescens). | 1973 | 4205758 | |
| glycerol ester hydrolase, lipase, of myxococcus xanthus fb. | 1974 | 4208247 | |
| bactericidal action of an antibiotic produced by myxococcus xanthus. | myxococcus xanthus produced an antibiotic during the end of its exponential growth phase which was capable of inhibiting growth of several gram-positive and gram-negative bacteria. the antibiotic was bactericidal to growing cultures only; chloramphenicol inhibited the bactericidal action of the antibiotic. upon addition of the antibiotic to escherichia coli b, deoxyribonucleic acid and ribonucleic acid as well as turbidity of the culture continued to increase even after the viable count decrease ... | 1973 | 4208901 |
| growth of surface colonies of the gliding bacterium myxococcus xanthus. | 1974 | 4209297 | |
| composition of lipopolysaccharides from myxococcus fulvus and other fruiting and non-fruiting myxobacteria. | 1974 | 4209347 | |
| intracellular proteolytic activity in developing myxospores of myxococcus xanthus. | 1974 | 4209409 | |
| autolytic activity associated with myxospore formation in myxococcus xanthus. | 1974 | 4209485 | |
| inhibition of carotenoid synthesis in myxococcus fulvus (myxobacterales). | 1974 | 4211208 | |
| effect of spermidine on morphogenesis in myxococcus fulvus. | 1974 | 4211963 | |
| presence of amino acid dehydrogenases and transaminases in myxococcus xanthus during vegetative growth and myxospore formation. | the following enzymatic activities were demonstrated in myxococcus xanthus during growth and myxospore formation: l-alanine dehydrogenase (ec 1.4.1.1), l-glutamic acid dehydrogenase (ec 1.4.1.2), glycine dehydrogenase (ec 1.4.1.5), l-glutamic glyoxylate aminotransferase (ec 2.6.1.4), and l-alanine glyoxylate aminotransferase (ec 2.6.1.12). | 1974 | 4212265 |
| studies on gliding motility in myxococcus xanthus. | 1974 | 4215396 | |
| flexibacter elegans and myxococcus fulvus: aerobic gram-negative bacteria containing menaquinones as the only isoprenoid quinones. | 1974 | 4216336 | |
| cytochemistry of phosphatases in myxococcus xanthus. | an mg(2+)-dependent and a k(+)-stimulated adenosine triphosphatase were localized by cytochemistry at or near both surfaces of the cytoplasmic membrane of myxococcus xanthus. an alkaline and an acid phosphatase resided at the external surface of the membrane or in the periplasm. all enzymes could be extracted from partially fixed cells with mg(2+)-deficient buffers. suboptimal external phosphate elicited dissociation of adenosine triphosphatase from the membrane but not that of the unspecific ph ... | 1968 | 4234839 |
| comparative intermediary metabolism of vegetative cells and microcysts of myxococcus xanthus. | crude extracts of both vegetative cells and glycerol-induced microcysts of myxococcus xanthus contained the following enzyme activities: phosphofructokinase, phosphoglucoisomerase, fructose-1,6-diphosphatase, fructosediphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate carboxylase, citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogen ... | 1968 | 4302296 |
| membranes from myxococcus fulvus (myxobacterales) containing carotenoid glucosides. i. isolation and composition. | 1972 | 4340261 | |
| antagonistic effects of myxococcus xanthus on fungi. ii. isolation and characterization of inhibitory lipid factors. | 1973 | 4356271 | |
| de novo purine synthesis in vegetative cells and myxospores of myxococcus xanthus. | this study was designed to determine whether vegetative cells and myxospores of myxococcus xanthus were capable of classical de novo purine biosynthesis. to answer this question, vegetative and myxospore extracts of m. xanthus fba were tested for their ability to synthesize the second de novo intermediate, 5'-phosphoribosylglycinamide, from beginning precursors either by way of phosphoribosyl-pyrophosphate amido transferase (ec 2.4.2.14) or ribose-5-phosphate amino transferase. both the amido an ... | 1974 | 4360538 |
| inactivation of isocitrate lyase during myxospore development in myxococcus xanthus. | the inactivation of isocitrate lyase which occurs during late stages of myxospore formation in myxococcus xanthus was studied. several findings are reported. (i) protein synthesis is required over a specific time interval in order for isocitrate lyase inactivation to occur at a later time. (ii) metabolic energy is required at all times during myxospore development if the inactivation is to occur. (iii) it was possible to inhibit protein turnover to a considerable extent without affecting the net ... | 1974 | 4362466 |
| purification and partial characterization of an antibiotic produced by myxococcus xanthus. | 1974 | 4362757 | |
| intracellular and extracellular nucleotides and related compounds during the development of myxococcus xanthus. | changes in nucleotide pools and extracellular nucleotides during the developmental cycle of the myxobacterium myxococcus xanthus were determined using a high-pressure liquid chromatography nucleotide analyzer. a general increase in all nucleotide pools occurred during the morphological phase of glycerol conversion of vegetative cells to myxospores. the levels of the nucleoside triphosphate pools remained high as the myxospore matured and throughout subsequent germination. oxidized nicotinamide a ... | 1974 | 4364021 |
| bacteriolytic enzymes produced by myxococcus xanthus. | the bacteriolytic activities in the culture fluid of myxococcus xanthus were purified and separated into six active fractions by the use of bio-gel cm-2 and bio-gel p-60. these fractions were identified as: (i) an amidase, (ii) a glucosaminidase, (iii) a glucosaminidase and an amidase, (iv) a protease with probable amidase activity, (v) another protease with probable amidase activity, and (vi) a peptidase active on both d-alanyl-diaminopimelate and d-alanyl-lysine peptide bonds. on one occasion, ... | 1972 | 4622898 |
| ribonucleic acid and protein synthesis during germination of myxococcus xanthus myxospores. | ribonucleic acid (rna) and protein synthesis during myxospore germination were examined. when rna synthesis was inhibited more than 90% by either actinomycin d (act d) or rifampin, germination was prevented. the data were consistent with the interpretation that rifampin did not interfere with protein synthesis in any way other than by inhibition of messenger rna formation. act d concentrations as high as 20 mug/ml did not totally inhibit rna synthesis. in the presence of 8 mug of act d/ml, germi ... | 1973 | 4690965 |
| biosynthesis of carotenoid glucoside esters in myxococcus fulvus (myxobacterales): inhibition by nicotine and carotenoid turnover. | 1973 | 4713154 | |
| aspartokinase of myxococcus xanthus: "feedback stimulation" by required amino acids. | the aspartokinase activity found in extracts of the bacterium myxococcus xanthus was subject to feedback inhibition and feedback repression by l-threonine and l-lysine. both types of inhibition were essentially additive. the required amino acids, l-isoleucine and l-methionine, caused considerable increase in the activity of the enzyme. this phenomenon is referred to as "feedback stimulation." the polyamine, spermidine, exerted strong enhancement of the activity even at 0.1 mm. meso-diaminopimela ... | 1973 | 4717514 |
| aspartokinase activity and the developmental cycle of myxococcus xanthus. | the relationship between aspartokinase activity and fruiting body formation in myxococcus xanthus was investigated. two required amino acids, methionine and isoleucine, which stimulated the enzyme in vitro also inhibited fruiting body formation when added to 0.1% casitone agar. threonine, a potent feedback inhibitor of the aspartokinase, completely reversed the effects of methionine and isoleucine both on enzyme activity and fruiting body formation. a mutant, m. xanthus fb-s, which had the unusu ... | 1973 | 4717518 |
| some aspects of amino acid metabolism in the fruiting myxobacterium, myxococcus xanthus. | 1973 | 4725820 | |
| comparative study of ribosomal ribonucleic acid cistrons in enterobacteria and myxobacteria. | deoxyribonucleic acid (dna)-ribonucleic acid (rna) hybrids are formed by escherichia coli 16s or 23s ribosomal rna or pulse-labeled rna with the dna of various species of the enterobacteriaceae. the relative extent of hybrid formation is always greater for ribosomal rna. these dna-rna hybrids have been further characterized by their stability to increasing temperature, and, in every case, the stability of pulse-labeled rna hybrids was lower than that of the corresponding ribosomal rna hybrids, a ... | 1967 | 4860906 |
| nutrition of myxococcus xanthus fba and some of its auxotrophic mutants. | a defined medium containing 15 amino acids plus salts was used to study the nutrition of myxococcus xanthus fba. the amino acids phenylalanine, leucine, isoleucine, valine, and methionine were essential for growth, whereas glycine, proline, asparagine, alanine, lysine, and threonine stimulated growth. an unusual pattern of requirement was found in the aromatic amino acids. phenylalanine was essential and served as the precursor of tyrosine. growth in the absence of tryptophan was adaptive, with ... | 1968 | 4868349 |
| a unique structure in microcysts of myxococcus xanthus. | 1967 | 4873038 | |
| gliding motility mutants of myxococcus xanthus. | two gliding motility mutants of myxococcus xanthus are described. the semimotile mutant (sm) originated by high-frequency segregation from the motile fb(t) strain. segregation was enhanced by acridine dye treatment. sm cells glide only when apposed to other cells in a swarm. the nonmotile strain (nm) originated by mutation from sm. nm cells neither glide individually nor cooperatively. fb(t), sm, and nm are indistinguishable with respect to fine structure, vegetative growth rate, glycerol-induce ... | 1970 | 4923078 |
| division cycle of myxococcus xanthus. 3. kinetics of cell growth and protein synthesis. | the kinetics of cell growth and protein synthesis during the division cycle of myxococcus xanthus was determined. the distribution of cell size for both septated and nonseptated bacteria was obtained by direct measurement of the lengths of 8,000 cells. the collins-richmond equation was modified to consider bacterial growth in two phases: growth and division. from the derived equation, the growth rate of individual cells was computed as a function of size. nondividing cells (growth phase) compris ... | 1971 | 4926683 |