Publications

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carotenoid pigments of stigmatella aurantiaca (myxobacterales).i. the minor carotenoids. 19694315734
studies on stigmatella brunnea. 19694894284
fine structure of fruiting bodies of stigmatella aurantiaca (myxobacterales).the fruiting body of stigmatella aurantiaca consists of a thick stalk supporting a number of individual cysts. the stalk is made of discontinuous tubules, of dimensions known for vegetative cells, which are oriented parallel to the longitudinal axis of the stalk. the red-brown cysts contain numerous, randomly oriented myxospores which are surrounded by thick, fibrous capsules. their cell walls are wavy or ruffled and exhibit fewer budlike infoldings than reported for myxospores induced in liquid ...19695370282
structural changes in stigmatella aurantiaca during myxospore induction.suspension cultures of stigmatella aurantiaca (chondromyces aurantiacus) were induced to form myxospores by addition of glycerol to the growing culture. the cells were fixed at various stages during conversion, thin sections were prepared, and changes in fine structure were studied. vegetative cells are quite similar in their ultrastructure to myxococcus xanthus. during transformation into myxospores, three important cytological changes were observed. granules of storage material, probably polys ...19695773035
induction of myxospore formation in stigmatella aurantiaca (myxobacterales) by monovalent cations.suspension cultures of stigmatella aurantiaca can be induced to form myxospores by addition of the monovalent cations li(+), na(+), nh(4) (+), k(+), or rb(+).19705411755
carotenoid pigments of stigmatella aurantiaca (myxobacterales). ii. acylated carotenoid glucosides. 19705495385
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 ...19734197903
scanning electron microscopy of fruiting body formation by myxobacteria.scanning electron microscopy was used to follow fruiting body formation by pure cultures of chondromyces crocatus m38 and stigmatella aurantica. vegetative cells were grown on sp agar and then transferred to bonner salts agar for fructification. fruiting in both species commences with the formation of aggregation centers which resemble a fried egg in appearance. in chondromyces the elevated center or "yolk" region of the aggregation enlarges into a bulbous structure under which the stalk forms a ...1975811649
carotenoid pigments of facultatively anaerobic spirochetes.carotenoid pigments were purified from a previously undescribed, red, halophilic spirochete (spirochete rs1), and from spirochaeta aurantia strain j1. both spirochetes are facultative anaerobes and produce pigments when growing aerobically. the major pigments of the two spirochetes were identified by means of chromatographic analysis, absorption spectroscopy, hydride reduction, acetylation and silylation experiments, and mass spectrometry. it was concluded that the major pigment from spirochete ...19751158846
myxobacters from arid mexican soil.myxobacters were found to be common inhabitants of the arid soils from the monterrey, nuevo leon, mexico, area. thirteen species of the genera myxococcus, archangium, cystobacter, stigmatella, polyangium, and chondromyces were isolated on a mineral salts agar supplemented with bakers' yeast and filter paper. greater species diversity per soil sample was found in the region receiving 400 to 800 mm of annual rainfall as compared with soils from an area having only 200 to 400 mm of rainfall.197616345178
light-stimulated morphogenesis in the fruiting myxobacterium stigmatella aurantiaca.when the fruiting myxobacterium stigmatella aurantiaca, a gliding prokaryote, is starved on an agar surface, the cells form multicellular aggregates resulting from morphogenetic movements. in the presence of incandescent light, each aggregate develops into a structurally complex fruiting body, possessing a stalk and several sporangia. in contrast, this pattern of development is not seen when cultures are incubated in the dark. the cells form irregular interconnecting aggregates, which rarely dev ...197896528
morphogenetic movements and multicellular development in the fruiting myxobacterium, stigmatella aurantiaca. 1978109333
distribution of adenosine 5'-triphosphate (atp)-dependent hexose kinases in microorganisms.a systematic study of adenosine triphosphate (atp)-dependent hexose kinases among microorganisms has been undertaken. sixteen hexose kinases of five major types were partially purified from 12 microorganisms and characterized with respect to specificity for sugar and nucleotide substrates and michaelis constants for the sugar substrates. glucokinase activities that phosphorylate glucose and glucosamine are inhibited by n-acetyl-glucosamine and xylose, were found to be present in the non-sulphur ...1978214181
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 ...1979118159
[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 ...1979121178
morphogenetic effects of light and guanine derivatives on the fruiting myxobacterium stigmatella aurantiaca.when low cell densities of the myxobacterium stigmatella aurantiaca were starved on an inorganic salts and agar medium, cell aggregation and fruiting body formation showed a striking dependency upon the presence of light. this dependency was not manifested when sufficient amounts of guanosine or guanine nucleotides were added to the medium. light interacted cooperatively with suboptimal concentrations of guanine compounds to promote development. none of the other purine or pyrimidine derivatives ...19806252195
development of stigmatella aurantiaca: effects of light and gene expression.stigmatella aurantiaca, a gliding, gram-negative bacterium, exhibits complex developmental changes upon starvation. in the light the cells aggregate and develop multicellular fruiting bodies with stalks and sporangia within 20 h. between 23 and 27 h, sonication-resistant myxospores are synchronously formed inside the sporangia. on the other hand, in the dark, the cells aggregate and differentiate into myxospores between 13 and 27 h without forming stalks and sporangia. the pattern of protein syn ...19806767708
photocontrol of development by stigmatella aurantiaca.aggregation and fruiting body formation by stigmatella aurantiaca were stimulated most effectively by low irradiances of blue light between 400 and 500 nm. at higher irradiances, other wavelengths of light, including those in the far-red region of the spectrum, were also effective.19806769906
effects of specific cations on aggregation and fruiting body morphology in the myxobacterium stigmatella aurantiaca.the cation requirements for fruiting body formation in the myxobacterium stigmatella aurantiaca on agarose were determined. calcium alone caused the cells to aggregate into interconnecting ridges. under these conditions, stalk formation was severely depressed but sporangia frequently formed. the combination of magnesium and manganese was necessary for optimal formation of discrete aggregates (rather than ridges) and stalks. manganese inhibited sporangium development. the inclusion of calcium int ...19806774964
reexamination of the genome size of myxobacteria, including the use of a new method for genome size analysis.the genome sizes of two myxobacteria, myxococcus xanthus and stigmatella aurantiaca, were measured by renaturation analysis and also by a new method involving the quantitation of individual restriction fragments. in contrast to several previous reports, which indicate that m. xanthus has a genome size which is three to four times that of escherichia coli, the present measurements indicated that the m. xanthus genome is only about 24 to 53% larger than that of e. coli. s. aurantiaca had a genome ...19816259127
pheromone produced by the myxobacterium stigmatella aurantiaca.an extracellular, diffusible signaling molecule (pheromone) was produced by stigmatella aurantiaca during fruiting body formation. the pheromone decreased the aggregation period in both the light and the dark and substituted for light in stimulating the maturation of aggregates into fruiting bodies. the cells were more sensitive to lower concentrations of pheromone in the light than in the dark, possibly explaining the stimulation of aggregation and fruiting body formation by light. the pheromon ...19826276369
occurrence of dialkyl ether phospholipids in stigmatella aurantiaca dw4.we investigated the lipid composition of vegetative cells of stigmatella aurantiaca. four phospholipids were isolated and identified: phosphatidylethanolamine as the main component, phosphatidylglycerol, lysophosphatidylethanolamine in an exceptionally large amount (17%), and phosphatidylinositol (18 to 25%), rare in procaryotic cells. this composition did not change significantly during growth. the fatty acids of total lipids were found to be rather similar to those of other strains of myxobact ...19836402494
stigmatellin, a new antibiotic from stigmatella aurantiaca (myxobacterales). i. production, physico-chemical and biological properties.an antibiotic activity was extracted from the cell mass of the myxobacterium, stigmatella aurantiaca strain sg a15. the antibiotic was toxic for yeasts and filamentous fungi, but not for most bacteria. the compound had the molecular formula c30h42o7, appears to be a new antibiotic, and was named stigmatellin. in addition to stigmatellin, the strain produced relatively large quantities of a second, structurally unrelated antibiotic, a mixture of three myxalamid homologues.19846429114
multicopy single-stranded dna isolated from a gram-negative bacterium, myxococcus xanthus.a gram-negative bacterium, myxococcus xanthus, was found to contain 500 to 700 copies per chromosome of a short single-stranded linear dna fragment. when this dna (multicopy single-stranded dna; msdna) labeled at the 5' end with kinase was used as a probe against total chromosomal blots, it hybridized to unique high molecular weight bands, which were cloned and sequenced. labeling of msdna was also possible using the klenow fragment of dna polymerase i as well as terminal deoxynucleotidyl transf ...19846088065
morphogenesis of stigmatella aurantiaca fruiting bodies.scanning electron micrographs of intermediate stages of fruiting body formation in the myxobacterium stigmatella aurantiaca suggest that fruiting body formation can be divided into several stages distinguishable on the basis of the motile behavior of the cells. aggregates formed at sites where cells glide as groups in circles or spirals. thus, each aggregate was surrounded by a wide band of cells. several streams of cells were pointed toward and connected to the wide band of cells at the base of ...19853926747
energy-dependent cell cohesion in myxobacteria.cohesion in the myxobacterium stigmatella aurantiaca was characterized. two classes of cohesion were revealed, termed class a and class b. class a cohesion is a characteristic of vegetative cells grown in tryptone or casitone (difco laboratories, detroit, mich.), whereas class b cohesion requires the addition of calcium ion for induction. class a cohesion occurs in the presence of any cation and is temperature independent. class b cohesion requires the presence of a cation in the calcium group a ...19853917996
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 ...19853932332
the aurachins, new quinoline antibiotics from myxobacteria: production, physico-chemical and biological properties.the aurachins, new quinoline alkaloids, were extracted with acetone from the biomass of the myxobacterium, stigmatella aurantiaca strain sg a15 and purified by column chromatography. the four described aurachins a, b, c and d, were inhibitory for gram-positive bacteria and a few yeasts and molds. they blocked nadh oxidation in beef heart submitochondrial particles.19873106289
biosynthesis and structure of stable branched rna covalently linked to the 5' end of multicopy single-stranded dna of stigmatella aurantiaca.stigmatella aurantiaca, a gram-negative bacterium, contains approximately 500 copies per cell of a short single-stranded linear dna (multicopy single-stranded dna: msdna). this dna is attached to a branched rna (msdrna) by its 5' end. the entire sequence of msdrna was determined and found to consist of 76 bases. the msdna is linked at the 19th g residue of msdrna by a 2', 5' phosphodiester linkage. the coding region for msdrna (msr) is located downstream of the coding region for msdna (msd). the ...19872431795
branched rna covalently linked to the 5' end of a single-stranded dna in stigmatella aurantiaca: structure of msdna.stigmatella aurantiaca is a gliding, gram-negative bacterium that shows a spectacular fruiting body formation upon starvation of nutrient. this bacterium was found to contain approximately 500 copies per cell of a short single-stranded linear dna (multicopy single-stranded dna: msdna). the primary structure of msdna was determined and found to consist of 162 or 163 deoxyribonucleotides. its unique chromosomal gene was cloned and sequenced. the msdna was found to be attached to a branched rna by ...19872431793
mutations that affect production of branched rna-linked msdna in myxococcus xanthus.a deletion mutation of the gene (msd-msr) for the branched rna-linked msdna of myxococcus xanthus was constructed by replacing the chromosomal 0.7-kilobase (kb) smai-xhoi fragment encompassing msd-msr with a 1.4-kb fragment carrying a gene for kanamycin resistance. it was found that this deletion strain (delta mssx) could not produce msdna, although it still contained another species of msdna, mrdna (msdna, reduced size). no apparent differences between delta mssx and the wild-type strain were o ...19882461359
transfer of incp plasmids into stigmatella aurantiaca leading to insertional mutants affected in spore development.derivatives of the broad-host-range plasmid rp4, containing the wild-type or modified transposon tn5 were transferred by conjugation to various stigmatella aurantiaca isolates. the transposons and in some cases fragments of the plasmid as well were integrated into the chromosome. thus, insertional mutants have been obtained affected in spore formation in liquid culture.19882853291
evidence for a membrane-associated gtp-binding protein in stigmatella aurantiaca, a prokaryotic cell.signal transducing g proteins are present in all eukaryotic cells, but they have not been found in prokaryotes so far. myxobacteria, especially stigmatella aurantiaca, are prokaryotic organisms able to exchange signals. moreover, they exhibit an active phosphoinositide metabolism, whose intensity is dependent on the physiological state of the cell. therefore g proteins potentially involved in the activation of phospholipid metabolism or any other event stimulated by external signals were looked ...19892492803
calcium requirement for gliding motility in myxobacteria.the ability to glide on a solid surface was inducible by calcium ion in stigmatella aurantiaca. the induction of motility but not motility itself was prevented by chloramphenicol and erythromycin. calcium ion was also required for cells to glide, even when they were previously induced. the ability of myxococcus xanthus to glide in groups using the s motility system but not as single cells (a system) was prevented by chloramphenicol and erythromycin.19892509428
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 ...19921372604
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 ...19921378616
size and stability of the genomes of the myxobacteria stigmatella aurantiaca and stigmatella erecta.genomic dna of stigmatella aurantiaca dw 4/3.1 was restricted with the rare-cutting endonucleases asei and spei. the restriction pattern derived is composed of 33 asei and 25 spei fragments, whose total size amounts to approximately 9,350 kbp. genomic fingerprint analysis of chromosomal dna from several s. aurantiaca isolates further revealed five completely different spei and asei fingerprints and one distinct fingerprint for stigmatella erecta. in addition, minor variations between the genome ...19921400181
cloning and dna sequence of sigb gene of stigmatella aurantiaca. 19921475207
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 ...19921522058
purification of the dna-dependent rna polymerase from the myxobacterium stigmatella aurantiaca.the dna-dependent rna polymerase (ec 2.7.7.6) of the myxobacterium stigmatella aurantiaca has been purified. it shows three main polypeptide bands with apparent molecular weights of 146,000, 105,000, and 40,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. beta and beta' subunits of the s. aurantiaca polymerase were shown to migrate in the 146,000-molecular-weight polypeptide band and the main sigma factor was shown to migrate in the 105,000-molecular-weight band by using heterol ...19921556092
heat shock and development induce synthesis of a low-molecular-weight stress-responsive protein in the myxobacterium stigmatella aurantiaca.in the fruiting body-forming myxobacterium stigmatella aurantiaca a 21,000-m(r) protein, sp21, is synthesized during fruiting, heat shock, and stress induced by oxygen limitation. the corresponding gene was isolated from a gene expression library in lambda gt11 with an antiserum to the purified protein. the dna sequence of the gene reveals that sp21 is a member of the alpha-crystallin family of low-molecular-weight heat shock proteins.19938226695
purification and characterization of sp21, a development-specific protein of the myxobacterium stigmatella aurantiaca.stigmatella aurantiaca is a gram-negative bacterium with a complex life cycle, including cellular aggregation resulting in the formation of a characteristic three-dimensional structure, the so-called fruiting body. during fruiting and upon chemical induction of sporulation, a major development-specific protein, sp21, is synthesized. sp21 was purified to homogeneity from the membranous fraction of chemically induced spores. expression of sp21 was studied with an antiserum raised against the purif ...19938423161
selective amplification of dna fragments coding for the g domain of factors if2 and ef-tu, two g proteins from the myxobacterium stigmatella aurantiaca.two dna fragments of the genome of the myxobacterium stigmatella aurantiaca were selectively amplified by pcr. these fragments encode a segment of the g domain of translational initiation factor if2 and elongation factor ef-tu, two gtp-binding proteins. this was made possible by carefully designing the primers for this reaction to avoid the amplification of every g-domain-encoding region of the genome. the sequence of two pairs of primers was deduced from highly conserved regions, namely g1 and ...19938118402
a physical and genetic map of the stigmatella aurantiaca dw4/3.1 chromosome.a physical map of the myxobacterium stigmatella aurantiaca dw4/3.1 chromosome was constructed by pulsed-field gel (pfg) long-range mapping. one-and two-dimensional pulsed-field gel analyses were used together with reciprocal double-restriction, cross-hybridization and hybridization fingerprint analysis. these pfg results were confirmed by smith-birnstiel analysis, by southern hybridization using linking clones and clones of a lambda genomic library for the determination of adjacent restriction f ...19937934859
isolated fibrils rescue cohesion and development in the dsp mutant of myxococcus xanthus.extracellular fibrils are involved in cell cohesion and cell development in myxococcus xanthus. one group of social motility mutants, dsp, is unable to produce extracellular fibrils; these mutants also lose the abilities to cohere and to develop. extracellular fibrils isolated from vegetative wild-type cells and added to dsp cells fully restored the abilities of these cells to cohere and to undergo normal morphological development. the fibrils thus mimic the ability of intact, wild-type cells to ...19947961490
territorial interactions between two myxococcus species.it is unusual to find fruiting bodies of different myxobacteria occupying the same territory on natural samples. we were thus interested in determining whether myxobacteria establish territorial dominance and, if so, what the mechanism of that interaction is. we had previously observed that vegetative swarms of myxococcus xanthus and stigmatella aurantiaca placed close to each other on an agar surface initially merged but eventually separated. further studies indicated that these two species als ...19948106334
stimulation of inositide degradation in clumping stigmatella aurantiaca.numerous external signals which activate inositol phospholipid hydrolysis in eukaryotes are known; probably all of these signals are transduced by g proteins. so far, neither signal-transducing g protein nor receptor-regulated phospholipase c has been found in prokaryotes. however, a group of bacteria, the myxobacteria, displays cellular and tissue-like differentiation; therefore, it appeared that a search for the various activities involved in a signal-activated phosphatidylinositol cycle might ...19948113179
cloning and characterization of the gene encoding the major sigma factor of stigmatella aurantiaca.the gene (siga) encoding the major sigma factor of the myxobacterium, stigmatella aurantiaca, was cloned and sequenced. the deduced polypeptide contains 706 amino acids (aa) and has a deduced m(r) of 79,910. it exhibits four different aa sequence motifs which correlate with the conserved domains of the major sigma factors of myxococcus xanthus (sigma 80), escherichia coli (sigma 70) and bacillus subtilis (sigma 43). the sigma factor (sigma a) was detected in crude lysates of vegetative cells and ...19948200526
purification and characterization of an endo-n-acetyl-beta-d-glucosaminidase from the culture medium of stigmatella aurantiaca dw4.a novel endo-n-acetyl-beta-d-glucosaminidase (engase), acting on the di-n-acetylchitobiosyl part of n-linked glycans, was characterized in the culture medium of stigmatella aurantiaca dw4. purified to homogeneity by ammonium sulfate precipitation, gel filtration, and chromatofocusing, this engase presents, upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a molecular mass near 27 kda. optimal ph and pi were 4.0 and 6.8, respectively. the enzyme, named engase st, exhibits high activ ...19947928985
localization of the stress protein sp21 in indole-induced spores, fruiting bodies, and heat-shocked cells of stigmatella aurantiaca.the localization and distribution of the stress protein sp21 in indole-induced vegetative cells, fruiting bodies, and heat shocked cells of stigmatella aurantiaca were determined by immunoelectron microscopy. sp21 was found at the cell periphery in heat-shocked cells and either at the cell periphery or within the cytoplasm in indole-induced cells, often concentrated in clusters. in fruiting-body-derived spores, sp21 was located mainly at the cell wall, preferentially at the outer periphery. furt ...19958522514
genetic and molecular analysis of the trna-tufb operon of the myxobacterium stigmatella aurantiaca.the tufb gene, encoding elongation factor tu (ef-tu), from the myxobacterium stigmatella aurantiaca was cloned and sequenced. it is preceded by four trna genes, the first ever described in myxobacteria. the trna synthesized from these genes and the general organization of the locus seem identical to that of escherichia coli, but differences of potential importance were found in the trna sequences and in the intergenic regions. the primary structure of ef-tu was deduced from the tufb dna sequence ...19957784178
the gene encoding the beta-1,4-endoglucanase (cela) from myxococcus xanthus: evidence for independent acquisition by horizontal transfer of binding and catalytic domains from actinomycetes.the cela gene encoding a beta-1,4 endoglucanase (cela) from myxococcus xanthus has been cloned in escherichia coli and sequenced. the c-terminal region of cela displayed a high level of similarity with the catalytic domain of several egl belonging to the glycosyl hydrolases family 6 (cena from cellulomonas fimi, cela from microbispora bispora, e2 from thermonospora fusca, casa from streptomyces ksm9 and cela1 from streptomyces halstedii) and less similarity to the cellobiohydrolases of the fungi ...19957789807
phylogenetic comparison of retron elements among the myxobacteria: evidence for vertical inheritance.twenty-eight myxobacterial strains, representing members from all three subgroups, were screened for the presence of retron elements, which are novel prokaryotic retroelements encoding reverse transcriptase. the presence of retrons was determined by assaying strains for a small satellite dna produced by reverse transcription called multicopy, single-stranded dna (msdna). an msdna-producing retron appeared to be absent from only one of the strains surveyed. dna hybridization experiments revealed ...19957798147
an endo-n-acetyl-beta-d-glucosaminidase, acting on the di-n-acetylchitobiosyl part of n-linked glycans, is secreted during sporulation of myxococcus xanthus.after the demonstration that stigmatella aurantiaca dw4 secretes an endo-n-acetyl-beta-d-glucosaminidase (engase), acting on the di-n-acetylchitobiosyl part of n-linked glycans (s. bourgerie, y. karamanos, t. grard, and r. julien, j. bacteriol. 176:6170-6174, 1994), an engase activity having the same substrate specificity was also found to be secreted during vegetative growth of myxococcus xanthus dk1622. the activity decreased in mutants known to secrete less protein than the wild type (exc +/- ...19957860600
the effects of decyl aurachins c and d on the respiratory electron flow of facultative phototrophic bacteria.decyl aurachins c and d are two synthetic compounds related to the natural products aurachins c and d extracted from stigmatella aurantiaca. titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin c is more effective than aurachin d in inhibiting the quinol oxidase. decyl aurachin c also affects the nadh-ubiquinone oxidoreductase of rhodobacter capsulatus and the cytochrome bc1 complexes of rb.capsulatus and rhodospirillum ce ...19968843334
stigmatella aurantiaca fruiting body formation is dependent on the fbfa gene encoding a polypeptide homologous to chitin synthases.stigmatella aurantiaca is a prokaryotic organism that undergoes a multicellular cycle of development resulting in the formation of a fruiting body. for analyzing this process, mutants defective in fruiting body formation have been induced by transposon mutagenesis using a tn5-derived transposon. about 800 bp upstream of the transposon insertion of mutant ap182 which inactivates a gene (fbfb) involved in fruiting, a further gene (fbfa) needed for fruiting body formation was detected. inactivation ...19968955286
translation initiation factor if2 of the myxobacterium stigmatella aurantiaca: presence of a single species with an unusual n-terminal sequence.the structural gene for translation initiation factor if2 (infb) was isolated from the myxobacterium stigmatella aurantiaca on a 5.18-kb bamhi genomic restriction fragment. the infb gene (ca. 3.16 kb) encodes a 1,054-residue polypeptide with extensive homology within its g domain and c terminus with the equivalent regions of if2s from escherichia coli, bacillus subtilis, bacillus stearothermophilus, and streptococcus faecium. the n-terminal region does not display any significant homology to oth ...19979079922
bifunctional structure of two adenylyl cyclases from the myxobacterium stigmatella aurantiaca.two adenylyl cyclase genes (cyaa and cyab) from the myxobacterium stigmatella aurantiaca were cloned by complementation of escherichia coli mutants defective in the cya gene. cyaa codes for a protein of 424 amino acid residues (ac1), while cyab encodes a protein of 352 residues (ac2). both cyclases are sensitive to adenosine: camp production was strongly inhibited in e coli cells and cell extracts expressing these genes. ac1 comprises a hydrophobic domain of six transmembrane helices coupled to ...19979523018
independent patterns of expression of two alternative sigma factors, sigb and sigc, of the myxobacterium stigmatella aurantiaca during development.the transcription of many spatially and temporally controlled developmental genes is required for cellular differentiation of the myxobacterium stigmatella aurantiaca. the expression patterns of the sigma factor gene sigb and of a novel alternative sigma factor gene sigc have been studied during development of stigmatella aurantiaca. they are expressed at different stages of development. sigb is expressed from the very beginning of fruiting body formation to the sporulation step, while sigc expr ...19989700054
intercellular signaling in stigmatella aurantiaca: purification and characterization of stigmolone, a myxobacterial pheromone.the myxobacterium stigmatella aurantiaca passes through a life cycle that involves formation of a multicellular fruiting body as the most complex stage. an early step in this differentiation process depends on a signal factor secreted by the cells when nutrients become limited. the formation of a fruiting body from a small cell population can be accelerated by addition of this secreted material. the bioactive compound was found to be steam volatile. it was purified to homogeneity by steam distil ...19989736724
structure elucidation and chemical synthesis of stigmolone, a novel type of prokaryotic pheromone.approximately 2 micromol of a novel prokaryotic pheromone, involved in starvation-induced aggregation and formation of fruiting bodies by the myxobacterium stigmatella aurantiaca, were isolated by a large-scale elution procedure. the pheromone was purified by hplc, and high-resolution ms, ir, 1h-nmr, and 13c-nmr were used to identify the active substance as the hydroxy ketone 2,5, 8-trimethyl-8-hydroxy-nonan-4-one, which has been named stigmolone. the analysis was complicated by a solvent-depend ...19989736725
fbfb, a gene encoding a putative galactose oxidase, is involved in stigmatella aurantiaca fruiting body formation.stigmatella aurantiaca is a gram-negative bacterium which forms, under conditions of starvation in a multicellular process, characteristic three-dimensional structures: the fruiting bodies. for studying this complex process, mutants impaired in fruiting body formation have been induced by transposon insertion with a tn5-derived transposon. the gene affected (fbfb) in one of the mutants (ap182) was studied further. inactivation of fbfb results in mutants which form only clumps during starvation i ...19989495764
metabolic diversity in myxobacteria: identification of the myxalamid and the stigmatellin biosynthetic gene cluster of stigmatella aurantiaca sg a15 and a combined polyketide-(poly)peptide gene cluster from the epothilone producing strain sorangium cellulosum so ce90.myxobacterial strains producing polyketides (pks) assumed to be biosynthesized by a type i polyketide synthase (pks) were analysed. myxobacteria also produce a variety of polypeptides (pp) and pks with incorporated amino acids ('mixed pk-pp'). in order to be able to identify the biosynthetic gene clusters for these metabolites a pcr based approach has been developed to clone ketosynthase (ks) domains of pks genes from these organisms. conserved regions of peptide synthetases of the non-ribosomal ...199910320771
the correlation between morphological and phylogenetic classification of myxobacteria.in order to determine whether morphological criteria are suitable to affiliate myxobacterial strains to species, a phylogenetic analysis of 16s rdnas was performed on 54 myxobacterial strains that represented morphologically 21 species of the genera angiococcus, archangium, chondromyces, cystobacter, melittangium, myxococcus, polyangium and stigmatella, five invalid species and three unclassified isolates. the analysis included 12 previously published sequences. the branching pattern confirmed t ...199910425789
purification of cold-shock-like proteins from stigmatella aurantiaca - molecular cloning and characterization of the cspa gene.prominent low-molecular-weight proteins were isolated from vegetative cells of the myxobacterium stigmatella aurantiaca and were found to be members of the cold-shock protein family. a first gene of this family (cspa) was cloned and sequenced. it encodes a protein of 68 amino acid residues that displays up to 71% sequence identity with other bacterial cold-shock(-like) proteins. a cysteine residue within the rnp-2 motif is a peculiarity of stigmatella cspa. a cspa::(deltatrp-lacz) fusion gene co ...199910460888
new lessons for combinatorial biosynthesis from myxobacteria. the myxothiazol biosynthetic gene cluster of stigmatella aurantiaca dw4/3-1.the biosynthetic mta gene cluster responsible for myxothiazol formation from the fruiting body forming myxobacterium stigmatella aurantiaca dw4/3-1 was sequenced and analyzed. myxothiazol, an inhibitor of the electron transport via the bc(1)-complex of the respiratory chain, is biosynthesized by a unique combination of several polyketide synthases (pks) and nonribosomal peptide synthetases (nrps), which are activated by the 4'-phosphopantetheinyl transferase mtaa. genomic replacement of a fragme ...199910601310
intercellular signalling in stigmatella aurantiaca.the myxobacterium stigmatella aurantiaca is a prokaryotic model used to study intercellular signalling and the genetic determination of morphogenesis. signalling factors and genes required for the generation of the elaborate multicellular fruiting body are to be identified. recently, the structure of stigmolone, which is the pheromone necessary for fruiting body formation, was elucidated, and genes involved in development were characterised. progress has also been made in the genetic accessibili ...199910607625
diastereo- and enantioselective total synthesis of stigmatellin a.stigmatellin a (1) isolated from the myxobacterium stigmatella aurantiaca is a powerful inhibitor of electron transport in mitochondria and chloroplasts. the first highly diastereo- and enantioselective total synthesis of this important natural product is described. key steps in the synthesis are the alkylation of the samp-hydrazone (s)-13, a titanium mediated syn-diastereoselective aldol reaction, the anti-diastereoselective triacetoxyborohydride reduction of the aldol adduct (r,r,s)-16, format ...200010840951
stigmatella aurantiaca sg a15 carries genes encoding type i and type ii 3-deoxy-d-arabino-heptulosonate-7-phosphate synthases: involvement of a type ii synthase in aurachin biosynthesis.3-deoxy-d-arabino-heptulosonate-7-phosphate (dahp) synthases catalyse the first step of the shikimate pathway. two unrelated dahp synthase types have been described in plants and bacteria. two type ii (aroa(a2) and aroa(a5)) and one type i dahp synthase gene (aroa001) were identified from the myxobacterium stigmatella aurantiaca sg a15. inactivation of aroa(a5) leads to a mutant that is impaired in the biosynthesis of aurachins, which are electron transport inhibitors and contain an anthranilate ...200010896221
the myxochelin iron transport regulon of the myxobacterium stigmatella aurantiaca sg a15.the biosynthetic gene cluster of the myxochelin-type iron chelator was cloned from stigmatella aurantiaca sg a15 and characterized. this catecholate siderophore was only known from two other myxobacteria. the biosynthetic genes of 2,3-dihydroxybenzoic acid are located in the cluster (mxcc-mxcf). two molecules of 2, 3-dihydroxybenzoic acid are activated and condensed with lysine in a unique way by a protein homologous to nonribosomal peptide synthetases (mxcg). inactivation of mxcg, which encodes ...200011029592
initiation factor 2 of myxococcus xanthus, a large version of prokaryotic translation initiation factor 2.we have isolated the structural gene for translation initiation factor if2 (infb) from the myxobacterium myxococcus xanthus. the gene (3.22 kb) encodes a 1,070-residue protein showing extensive homology within its g domain and c terminus to the equivalent regions of if2 from escherichia coli. the protein cross-reacts with antibodies raised against e. coli if2 and was able to complement an e. coli infb mutant. the m. xanthus protein is the largest if2 known to date. this is essentially due to a l ...200111114918
the mtaa gene of the myxothiazol biosynthetic gene cluster from stigmatella aurantiaca dw4/3-1 encodes a phosphopantetheinyl transferase that activates polyketide synthases and polypeptide synthetases.myxothiazol is synthesized by the myxobacterium stigmatella aurantiaca dw4/3-1 via a combined polyketide synthase/polypeptide synthetase. the biosynthesis of this secondary metabolite is also dependent on the gene product of mtaa. the deduced amino acid sequence of mtaa shows similarity to 4'-phosphopantetheinyl transferases (4'-pp transferase). this points to an enzyme activity that converts inactive forms of the acyl carrier protein domains of polyketide synthetases (pkss) and/or the peptidyl ...200111134965
novel features in a combined polyketide synthase/non-ribosomal peptide synthetase: the myxalamid biosynthetic gene cluster of the myxobacterium stigmatella aurantiaca sga15.myxobacteria have been well established as a potent source for natural products with biological activity. they produce a considerable variety of compounds which represent typical polyketide structures with incorporated amino acids (e.g. the epothilons, the myxothiazols and the myxalamids). several of these secondary metabolites are effective inhibitors of the electron transport via the respiratory chain and have been widely used. molecular cloning and characterization of the genes governing the ...200111182319
sigb, an alternative sigma factor of the myxobacterium stigmatella aurantiaca, is synthesized during development and heat shock.alternative sigma factors have been detected in the myxobacterium stigmatella aurantiaca during indole-induced sporulation, fruiting body formation and heat shock using an antiserum raised against sigma factor sigb. the time course of sigb gene expression was analysed by rt-pcr and by determining beta-galactosidase activity during development in a merodiploid strain that harboured a sigb-lacz fusion gene. inactivation of the sigb gene by insertion of the neo gene resulted in the loss of one sigm ...200111496003
in vitro reconstitution of the myxochelin biosynthetic machinery of stigmatella aurantiaca sg a15: biochemical characterization of a reductive release mechanism from nonribosomal peptide synthetases.microorganisms produce iron-chelating compounds to sequester the iron essential for growth from the environment. many of these compounds are biosynthesized by nonribosomal peptide synthetases, some in cooperation with polyketide synthases. myxochelins are produced by the myxobacterium stigmatella aurantiaca sg a15, and the corresponding gene cluster was cloned recently. we have undertaken to express heterologously the myxochelin biosynthetic machinery in escherichia coli. to activate the involve ...200111562468
multiple hybrid polyketide synthase/non-ribosomal peptide synthetase gene clusters in the myxobacterium stigmatella aurantiaca.many bacterial and fungal secondary metabolites are produced by polyketide synthases (pks) and non-ribosomal peptide synthetases (nrps). recently, it has been discovered that these modular enzymatic systems can also closely cooperate to form natural products. the analysis of the corresponding biosynthetic machineries, in the form of hybrid systems, is of special interest for combinatorial biosynthesis, because the combination of pks and nrps can lead to an immense variety of structures that migh ...200111587850
the biosynthesis of the aromatic myxobacterial electron transport inhibitor stigmatellin is directed by a novel type of modular polyketide synthase.deductions from the molecular analysis of the 65,000-bp stigmatellin biosynthetic gene cluster are reported. the biosynthetic genes (stia-j) encode an unusual bacterial modular type i polyketide synthase (pks) responsible for the formation of this aromatic electron transport inhibitor produced by the myxobacterium stigmatella aurantiaca. involvement of the pks gene cluster in stigmatellin biosynthesis is shown using site-directed mutagenesis. one module of the pks is assumed to be used iterative ...200211809757
a novel biosynthetic pathway providing precursors for fatty acid biosynthesis and secondary metabolite formation in myxobacteria.short chain carboxylic acids are well known as the precursors of fatty acid and polyketide biosynthesis. iso-fatty acids, which are important for the control of membrane fluidity, are formed from branched chain starter units (isovaleryl-coa and isobutyryl-coa), which in turn are derived from the degradation of leucine and valine, respectively. branched chain carboxylic acids are also employed as starter molecules for the biosynthesis of secondary metabolites, e.g. the therapeutically important a ...200212084727
steroid biosynthesis in prokaryotes: identification of myxobacterial steroids and cloning of the first bacterial 2,3(s)-oxidosqualene cyclase from the myxobacterium stigmatella aurantiaca.steroids, such as cholesterol, are synthesized in almost all eukaryotic cells, which use these triterpenoid lipids to control the fluidity and flexibility of their cell membranes. bacteria rarely synthesize such tetracyclic compounds but frequently replace them with a different class of triterpenoids, the pentacyclic hopanoids. the intriguing mechanisms involved in triterpene biosynthesis have attracted much attention, resulting in extensive studies of squalene-hopene cyclase in bacteria and (s) ...200312519197
the stigmatella aurantiaca homolog of myxococcus xanthus high-mobility-group a-type transcription factor card: insights into the functional modules of card and their distribution in bacteria.transcriptional factor card is the only reported prokaryotic analog of eukaryotic high-mobility-group a (hmga) proteins, in that it has contiguous acidic and at hook dna-binding segments and multifunctional roles in myxococcus xanthus carotenogenesis and fruiting body formation. hmga proteins are small, randomly structured, nonhistone, nuclear architectural factors that remodel dna and chromatin structure. here we report on a second at hook protein, card(sa), that is very similar to card and tha ...200312775690
a defined subset of adenylyl cyclases is regulated by bicarbonate ion.the molecular basis by which organisms detect and respond to fluctuations in inorganic carbon is not known. the cyab1 gene of the cyanobacterium anabaena sp. pcc7120 codes for a multidomain protein with a c-terminal class iii adenylyl cyclase catalyst that was specifically stimulated by bicarbonate ion (ec50 9.6 mm). bicarbonate lowered substrate affinity but increased reaction velocity. a point mutation in the active site (lys-646) reduced activity by 95% and was refractory to bicarbonate activ ...200312829712
solubilization and refolding of inclusion body proteins in reverse micelles.today, many valuable proteins can be obtained in sufficient amounts using recombinant dna techniques. however, frequently the expression of recombinant proteins results in the accumulation of the product in dense amorphous deposits inside the cells, called inclusion bodies. the challenge then is to transform these inactive and misfolded protein aggregates into soluble bioactive forms. although a number of general guidelines have been proposed, the search for proper reconstitution conditions can ...200312927829
melithiazol biosynthesis: further insights into myxobacterial pks/nrps systems and evidence for a new subclass of methyl transferases. 200314583260
markerless mutations in the myxothiazol biosynthetic gene cluster: a delicate megasynthetase with a superfluous nonribosomal peptide synthetase domain. 200314583261
the csbx gene of azotobacter vinelandii encodes an mfs efflux pump required for catecholate siderophore export.the csbx gene of azotobacter vinelandii was regulated in an iron-repressible manner from a divergent promoter upstream of the catecholate siderophore biosynthesis (csb) operon and was predicted to encode an efflux pump of the major facilitator superfamily. other proteins that were most similar to csbx were encoded by genes found in the catecholate siderophore biosynthesis operons of aeromonas hydrophila and stigmatella aurantiaca. inactivation of csbx resulted in 57-100% decrease in the amount o ...200314638426
signaling in myxobacteria.myxobacteria use soluble and cell-contact signals during their starvation-induced formation of fruiting bodies. these signals coordinate developmental gene expression with the cell movements that build fruiting bodies. early in development, the quorum-sensing a-signal in myxococcus xanthus helps to assess starvation and induce the first stage of aggregation. later, the morphogenetic c-signal helps to pattern cell movement and shape the fruiting body. c-signal is a 17-kda cell surface protein tha ...200415487930
a biosynthetic pathway to isovaleryl-coa in myxobacteria: the involvement of the mevalonate pathway.a biosynthetic shunt pathway branching from the mevalonate pathway and providing starter units for branched-chain fatty acid and secondary metabolite biosynthesis has been identified in strains of the myxobacterium stigmatella aurantiaca. this pathway is upregulated when the branched-chain alpha-keto acid dehydrogenase gene (bkd) is inactivated, thus impairing the normal branched-chain amino acid degradation process. we previously proposed that, in this pathway, isovaleryl-coa is derived from 3, ...200515619721
biosynthesis of iso-fatty acids in myxobacteria: iso-even fatty acids are derived by alpha-oxidation from iso-odd fatty acids.the biosynthesis of iso-fatty acids was investigated in the myxobacteria myxococcus xanthus and stigmatella aurantiaca by feeding labeled precursors of these fatty acids and by conducting detailed analysis of the fatty acid profiles and fatty acid ms and nmr spectra. these experiments revealed that in s. aurantiaca all iso-even fatty acids are formed via alpha-oxidation of iso-odd fatty acids and not by using valine-derived isobutyryl-coa.200515643871
structure and biosynthesis of myxochromides s1-3 in stigmatella aurantiaca: evidence for an iterative bacterial type i polyketide synthase and for module skipping in nonribosomal peptide biosynthesis.the myxobacterium stigmatella aurantiaca dw4/3-1 harbours an astonishing variety of secondary metabolic gene clusters, at least two of which were found by gene inactivation experiments to be connected to the biosynthesis of previously unknown metabolites. in this study, we elucidate the structures of myxochromides s1-3, novel cyclic pentapeptide natural products possessing unsaturated polyketide side chains, and identify the corresponding biosynthetic gene locus, made up of six nonribosomal pept ...200515651040
novel insights into siderophore formation in myxobacteria.the myxochelins are catecholate-type siderophores produced by a number of myxobacterial strains, and their corresponding biosynthetic gene clusters have been identified in stigmatella aurantiaca sg a15, and sorangium cellulosum so ce56; the latter being presented in this work. biochemical and genetic studies described here further clarify myxochelin biosynthesis. in addition to the myxochelin a biosynthetic complex, the aminotransferase mxcl is required in order to form myxochelin b, starting fr ...200515678426
exploiting pseudomonas putida for drug development.in this issue of chemistry & biology, a strategy that combines large dna fragment recombineering in escherichia coli and heterologous expression in pseudomonas putida is described. the work focuses on myxochromide s, a natural compound produced by stigmatella aurantiaca.200515797207
heterologous expression of a myxobacterial natural products assembly line in pseudomonads via red/et recombineering.natural products of microbial origin are widely used as pharmaceuticals and in agrochemistry. these compounds are often biosynthesized by multifunctional megasynthetases whose genetic engineering and heterologous expression offer considerable promise, especially if the natural hosts are genetically difficult to handle, slow growing, unculturable, or even unknown. we describe a straightforward strategy that combines the power of advanced dna engineering (recombiogenic cloning) in escherichia coli ...200515797219
the pyruvate kinase of stigmatella aurantiaca is an indole binding protein and essential for development.myxospore formation of the myxobacterium stigmatella aurantiaca can be uncoupled from the cooperative development i.e. fruiting body formation, by low concentrations of indole. two putative indole receptor proteins were isolated by their capacity to bind indole and identified as pyruvate kinase (pk) and aldehyde dehydrogenase. the pk activity of stigmatella crude extracts was stimulated by indole. cloning of the pk gene (pyka) and the construction of a pyka disruption mutant strikingly revealed ...200515882428
a novel type of geosmin biosynthesis in myxobacteria.the biosynthesis of geosmin (1) and (1(10)e,5e)-germacradien-11-ol (2), two volatile terpenoid compounds emitted by the myxobacteria myxococcus xanthus and stigmatella aurantiaca, was investigated in feeding experiments with different labeled precursors. in these experiments, the volatiles released by the cell cultures grown on agar plates were collected with a closed-loop stripping apparatus (clsa) and analyzed by gc-ms. [(2)h(10)]leucine and [4,4,4,5,5,5-(2)h(6)]dimethylacrylate were fed to wi ...200515960521
aurafuron a and b, new bioactive polyketides from stigmatella aurantiaca and archangium gephyra (myxobacteria). fermentation, isolation, physico-chemical properties, structure and biological activity.new antibiotic polyketides, named aurafuron a (1) and b (2) were isolated from culture extracts of myxobacteria of the species stigmatella aurantiaca and archangium gephyra, strain ar 10844. by multi-step chromatography 1 and 2 were separated from a variety of other non-related co-metabolites, and their structures elucidated by spectroscopic methods as new 5-alkenyl-3 3(2h)-furanones. aurafurons inhibited the growth of some filamentous fungi and additionally, aurafuron b was weakly active agains ...200515981410
biosynthesis of iso-fatty acids in myxobacteria.the fatty acid (fa) profiles of the myxobacteria stigmatella aurantiaca and myxococcus xanthus were investigated by acidic methanolysis of total cell extracts and gc or gc-ms analysis. the main components were 13-methyltetradecanoic acid (iso-15:0) and (z)-hexadec-11-enoic acid (16:1, omega-5 cis). the biosynthesis of iso-fas was investigated in several feeding experiments. feeding of isovaleric acid (iva) to a mutant impaired in the degradation of leucine to isovaleryl-coa (iv-coa)(bkd mutant) ...200516032360
biosynthesis and identification of volatiles released by the myxobacterium stigmatella aurantiaca.the volatiles released by agar plate cultures of two strains of the myxobacterium stigmatella aurantiaca (strains sg a15 and dw4/3-1) were collected in a closed-loop stripping apparatus (clsa) and analyzed by gc-ms. large numbers of substances from different compound classes (ketones, esters, lactones, terpenes, and sulfur and nitrogen compounds) were identified; several of them are reported from natural sources for the first time. the volatiles 2-methyltridecan-4-one (17), its isomer 3-methyltr ...200516208730
integration into the phage attachment site, attb, impairs multicellular differentiation in stigmatella aurantiaca.stigmatella aurantiaca displays a complex developmental life cycle in response to starvation conditions that results in the formation of tree-like fruiting bodies capable of producing spores. the phage mx8, first isolated from the close relative myxococcus xanthus, is unable to infect s. aurantiaca cells and integrate into the genome. however, plasmids containing mx8 fragments encoding the integrase and attp are able to integrate at the attb locus in the s. aurantiaca genome by site-specific rec ...200616484181
nonribosomal peptide biosynthesis: point mutations and module skipping lead to chemical diversity. 200616506259
a unique mechanism for methyl ester formation via an amide intermediate found in myxobacteria.secondary metabolism involves a broad diversity of biochemical reactions that result in a wide variety of biologically active compounds. terminal amide formation during the biosynthesis of the myxobacterial electron-transport inhibitor, myxothiazol, was analyzed by heterologous expression of the unique nonribosomal-peptide synthetase, mtag, and incubation with a synthesized substrate mimic. these experiments provide evidence that the terminal amide is formed from a carrier protein-bound myxothia ...200616807964
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