| similarity between the myxococcus xanthus and stigmatella aurantiaca reverse transcriptase genes associated with multicopy, single-stranded dna. | to determine the evolutional relationship of bacterial retroelements of myxococcus xanthus and stigmatella aurantiaca, the nucleotide sequence of 3,060 bases encompassing msr, msd, and the upstream region of msd (downstream of msr) of s. aurantiaca dw4 was determined and compared with the same region from m. xanthus. an open reading frame was found 92 bases upstream of msd which encoded a polypeptide of 480 amino acid residues having 73% identity with the reverse transcriptase of m. xanthus. tog ... | 1992 | 1372604 |
| in vivo production of a stable single-stranded cdna in saccharomyces cerevisiae by means of a bacterial retron. | gram-negative bacteria such as myxococcus xanthus, stigmatella aurantiaca, and escherichia coli contain retroelements called retrons. retrons consist of the msr-msd region and the gene for reverse transcriptase (rt), which are essential for the production of the branched rna-linked ms-dna (multicopy single-stranded dna). in this study, we attempted to produce msdna in the yeast saccharomyces cerevisiae. retron ec67 from e. coli, which is responsible for the production of msdna-ec67, was cloned u ... | 1992 | 1378616 |
| 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 ... | 1992 | 1400181 |
| cloning and dna sequence of sigb gene of stigmatella aurantiaca. | | 1992 | 1475207 |
| cell surface modifications induced by calcium ion in the myxobacterium stigmatella aurantiaca. | calcium ion induces in the myxobacterium stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (d. f. gilmore and d. white, j. bacteriol. 161:113-117, 1985; b. j. womack, d. f. gilmore, and d. white, j. bacteriol. 171:6093-6096, 1989). the addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kda protein, and the accumulation in a low-speed centrifugal pellet of 10 polypepti ... | 1992 | 1522058 |
| 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 ... | 1992 | 1556092 |
| 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 ... | 1988 | 2461359 |
| 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. | 1989 | 2509428 |
| 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 ... | 1985 | 3917996 |
| 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 ... | 1985 | 3926747 |
| 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 |
| 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 ... | 1980 | 6252195 |
| 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 ... | 1981 | 6259127 |
| 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 ... | 1982 | 6276369 |
| 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 ... | 1983 | 6402494 |
| 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 ... | 1980 | 6767708 |
| 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. | 1980 | 6769906 |
| 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 ... | 1980 | 6774964 |
| 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 ... | 1995 | 7784178 |
| 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 ... | 1995 | 7798147 |
| 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 +/- ... | 1995 | 7860600 |
| 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 ... | 1994 | 7928985 |
| 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 ... | 1994 | 7961490 |
| 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 ... | 1994 | 8106334 |
| 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 ... | 1994 | 8113179 |
| 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. | 1993 | 8226695 |
| 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 ... | 1993 | 8423161 |
| 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 ... | 1995 | 8522514 |
| 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 ... | 1996 | 8955286 |
| 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 ... | 1997 | 9079922 |
| mycobacterial stationary phase induced by low oxygen tension: cell wall thickening and localization of the 16-kilodalton alpha-crystallin homolog. | most cases of tuberculosis are due to reactivation of endogenous infection which may have lain quiescent or dormant for decades. how mycobacterium tuberculosis survives for this length of time is unknown, but it is hypothesized that reduced oxygen tension may trigger the tubercle bacillus to enter a state of dormancy. mycobacterium bovis bcg and m. tuberculosis h37rv were cultured under aerobic, microaerobic, and anaerobic conditions. their ultrastructural morphology was analyzed by transmission ... | 1998 | 9473032 |
| 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 ... | 1998 | 9495764 |
| cloning, characterization, and transcriptional analysis of a gene encoding an alpha-crystallin-related, small heat shock protein from the thermophilic cyanobacterium synechococcus vulcanus. | hspa, a gene encoding a 16-kda heat-induced protein from the thermophilic cyanobacterium synechococcus vulcanus, has been cloned and sequenced. the deduced amino acid sequence of the gene product showed significant homology to sequences of the family of alpha-crystallin-related, small heat shock proteins. a monocistronic mrna of hspa increased transiently in response to heat shock. the heat shock induction occurred at a vegetative promoter but without the circe (controlling inverted repeat of ch ... | 1998 | 9683501 |
| 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 ... | 1998 | 9736724 |
| 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 ... | 1998 | 9736725 |
| inhibition of development of myxococcus xanthus by eukaryotic protein kinase inhibitors. | myxococcus xanthus is a social bacterium that lives in the soil and undergoes spectacular development to form multicellular fruiting bodies. it contains a large family of eukaryote-like serine/threonine protein kinases. we found that a number of inhibitors for eukaryotic protein serine, threonine, and tyrosine kinases could inhibit the development and sporulation of m. xanthus to various degrees. these results suggest that serine/threonine and tyrosine phosphorylation may be involved in developm ... | 1998 | 9851997 |
| multiple small heat shock proteins in rhizobia. | seven genes coding for small heat shock proteins (shsps) in bradyrhizobium japonicum have been identified. they are organized in five operons that are coordinately regulated by rose, a negatively cis-acting dna element. the deduced shsps can be divided into two separate classes: class a, consisting of proteins that show similarity to escherichia coli ibpa and ibpb, and class b, whose members display significant similarity to other shsps from prokaryotes and eukaryotes. two-dimensional gel electr ... | 1999 | 9864316 |
| cytosolic adenylyl cyclase defines a unique signaling molecule in mammals. | mammals have nine differentially regulated isoforms of g protein-responsive transmembrane-spanning adenylyl cyclases. we now describe the existence of a distinct class of mammalian adenylyl cyclase that is soluble and insensitive to g protein or forskolin regulation. northern analysis indicates the gene encoding soluble adenylyl cyclase (sac) is preferentially expressed in testis. as purified from rat testis cytosol, the active form of sac appears to be a fragment derived from the full-length pr ... | 1999 | 9874775 |
| regulated exopolysaccharide production in myxococcus xanthus. | myxococcus xanthus fibrils are cell surface-associated structures composed of roughly equal amounts of polysaccharide and protein. the level of m. xanthus polysaccharide production under different conditions in the wild type and in several mutants known to have alterations in fibril production was investigated. wild-type exopolysaccharide increased significantly as cells entered the stationary phase of growth or upon addition of ca2+ to growing cells, and the polysaccharide-induced cells exhibit ... | 1999 | 10049381 |
| gliding motility in bacteria: insights from studies of myxococcus xanthus. | gliding motility is observed in a large variety of phylogenetically unrelated bacteria. gliding provides a means for microbes to travel in environments with a low water content, such as might be found in biofilms, microbial mats, and soil. gliding is defined as the movement of a cell on a surface in the direction of the long axis of the cell. because this definition is operational and not mechanistic, the underlying molecular motor(s) may be quite different in diverse microbes. in fact, studies ... | 1999 | 10477310 |
| spatial control of cell differentiation in myxococcus xanthus. | myxococcus xanthus develops species-specific multicellular fruiting bodies. starting from a uniform mat of cells, some cells enter into nascent fruiting body aggregates, whereas other cells remain outside. the cells within the fruiting body differentiate from rods into spherical, heat-resistant spores, whereas the cells outside the aggregates, called peripheral cells, remain rod-shaped. early developmentally regulated genes are expressed in peripheral cells as well as by cells in the fruiting bo ... | 2000 | 10922065 |
| evidence for horizontal gene transfer in evolution of elongation factor tu in enterococci. | the elongation factor tu, encoded by tuf genes, is a gtp binding protein that plays a central role in protein synthesis. one to three tuf genes per genome are present, depending on the bacterial species. most low-g+c-content gram-positive bacteria carry only one tuf gene. we have designed degenerate pcr primers derived from consensus sequences of the tuf gene to amplify partial tuf sequences from 17 enterococcal species and other phylogenetically related species. the amplified dna fragments were ... | 2000 | 11092850 |
| 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 ... | 2001 | 11114918 |
| structural analysis of adenylate cyclases from trypanosoma brucei in their monomeric state. | cyclic amp is a major trigger of the differentiation process of trypanosoma brucei, a bloodstream parasite causing sleeping sickness. its generation in trypanosomes is accomplished by a unique battery of membrane-bound adenylate cyclases (acs). we have determined the high-resolution x-ray structures of the catalytic domains of two trypanosomal acs (tacs), gresag4.1 and gresag4.3. the tac domains are structurally highly related to the ac domains of higher eukaryotes, but also comprise a highly co ... | 2001 | 11157750 |
| microbial origin of plant-type 2-keto-3-deoxy-d-arabino-heptulosonate 7-phosphate synthases, exemplified by the chorismate- and tryptophan-regulated enzyme from xanthomonas campestris. | enzymes performing the initial reaction of aromatic amino acid biosynthesis, 2-keto-3-deoxy-d-arabino-heptulosonate 7-phosphate (dahp) synthases, exist as two distinct homology classes. the three classic escherichia coli paralogs are aroa(i) proteins, but many members of the bacteria possess the aroa(ii) class of enzyme, sometimes in combination with aroa(i) proteins. aroa(ii) dahp synthases until now have been shown to be specifically dedicated to secondary metabolism (e.g., formation of ansamy ... | 2001 | 11395471 |
| indole can act as an extracellular signal in escherichia coli. | previous work has shown that lacz fusions to the cysk, astd, tnab, and gabt genes in escherichia coli are activated by self-produced extracellular signals. using a combination of ethyl acetate extraction, reversed-phase c(18) chromatography, and thin-layer chromatography, we have purified an extracellular activating signal from e. coli supernatants. mass spectrometry revealed a molecule with an m/z peak of 117, consistent with indole. nuclear magnetic resonance analysis of the purified e. coli f ... | 2001 | 11418561 |
| adenylyl cyclase rv1625c of mycobacterium tuberculosis: a progenitor of mammalian adenylyl cyclases. | the gene rv1625c from mycobacterium tuberculosis encodes a membrane-anchored adenylyl cyclase corresponding to exactly one-half of a mammalian adenylyl cyclase. an engineered, soluble form of rv1625c was expressed in escherichia coli. it formed a homodimeric cyclase with two catalytic centers. amino acid mutations predicted to affect catalysis resulted in inactive monomers. a single catalytic center with wild-type activity could be reconstituted from mutated monomers in stringent analogy to the ... | 2001 | 11447108 |
| the dictyostelium homologue of mammalian soluble adenylyl cyclase encodes a guanylyl cyclase. | a new dictyostelium discoideum cyclase gene was identified that encodes a protein (sgc) with 35% similarity to mammalian soluble adenylyl cyclase (sac). gene disruption of sgc has no effect on adenylyl cyclase activity and results in a >10-fold reduction in guanylyl cyclase activity. the scg- null mutants show reduced chemotactic sensitivity and aggregate poorly under stringent conditions. with mn(2+)/gtp as substrate, most of the sgc activity is soluble, but with the more physiological mg(2+)/g ... | 2001 | 11500361 |
| 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 ... | 2001 | 11562468 |
| characterization of a brucella species 25-kilobase dna fragment deleted from brucella abortus reveals a large gene cluster related to the synthesis of a polysaccharide. | in the present study we completed the nucleotide sequence of a brucella melitensis 16m dna fragment deleted from b. abortus that accounts for 25,064 bp and show that the other brucella spp. contain the entire 25-kb dna fragment. two short direct repeats of four nucleotides, detected in the b. melitensis 16m dna flanking both sides of the fragment deleted from b. abortus, might have been involved in the deletion formation by a strand slippage mechanism during replication. in addition to omp31, co ... | 2001 | 11598046 |
| characterization of indigoidine biosynthetic genes in erwinia chrysanthemi and role of this blue pigment in pathogenicity. | in the plant-pathogenic bacterium erwinia chrysanthemi production of pectate lyases, the main virulence determinant, is modulated by a complex network involving several regulatory proteins. one of these regulators, pecs, also controls the synthesis of a blue pigment identified as indigoidine. since production of this pigment is cryptic in the wild-type strain, e. chrysanthemi ind mutants deficient in indigoidine synthesis were isolated by screening a library of tn5-b21 insertions in a pecs mutan ... | 2002 | 11790734 |
| characterization and description of anaeromyxobacter dehalogenans gen. nov., sp. nov., an aryl-halorespiring facultative anaerobic myxobacterium. | five strains were isolated which form a physiologically and phylogenetically coherent group of chlororespiring microorganisms and represent the first taxon in the myxobacteria capable of anaerobic growth. the strains were enriched and isolated from various soils and sediments based on their ability to grow using acetate as an electron donor and 2-chlorophenol (2-cph) as an electron acceptor. they are slender gram-negative rods with a bright red pigmentation that exhibit gliding motility and form ... | 2002 | 11823233 |
| an adenylyl cyclase, cyaa, of myxococcus xanthus functions in signal transduction during osmotic stress. | an adenylyl cyclase gene (cyaa) present upstream of an osmosensor protein gene (moka) was isolated from myxococcus xanthus. cyaa encoded a polypeptide of 843 amino acids with a predicted molecular mass of 91,187 da. the predicted cyaa gene product had structural similarity to the receptor-type adenylyl cyclases that are composed of an amino-terminal sensor domain and a carboxy-terminal catalytic domain of adenylyl cyclase. in reverse transcriptase pcr experiments, the transcript of the cyaa gene ... | 2002 | 12057952 |
| a gaf-domain-regulated adenylyl cyclase from anabaena is a self-activating camp switch. | the gene cyab1 from the cyanobacterium anabaena sp. pcc 7120 codes for a protein consisting of two n-terminal gaf domains (gaf-a and gaf-b), a pas domain and a class iii adenylyl cyclase catalytic domain. the catalytic domain is active as a homodimer, as demonstrated by reconstitution from complementary inactive point mutants. the specific activity of the holoenyzme increased exponentially with time because the product camp activated dose dependently and nucleotide specifically (half-maximally a ... | 2002 | 12110580 |
| heterologous expression of epothilone biosynthetic genes in myxococcus xanthus. | epothilones are potential anticancer drugs that stabilize microtubules in a manner similar to paclitaxel (taxol). epothilones are produced from the myxobacterium sorangium cellulosum, which has a 16-h doubling time and produces only milligram-per-liter amounts of epothilone a and epothilone b. furthermore, genetic manipulation of s. cellulosum is difficult. to produce epothilones in a more genetically amenable and rapidly growing host, we chose the closely related and best-characterized myxobact ... | 2002 | 12183227 |
| recombinant environmental libraries provide access to microbial diversity for drug discovery from natural products. | to further explore possible avenues for accessing microbial biodiversity for drug discovery from natural products, we constructed and screened a 5,000-clone "shotgun" environmental dna library by using an escherichia coli-streptomyces lividans shuttle cosmid vector and dna inserts from microbes derived directly (without cultivation) from soil. the library was analyzed by several means to assess diversity, genetic content, and expression of heterologous genes in both expression hosts. we found th ... | 2003 | 12513976 |
| 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 ... | 2003 | 12775690 |
| the vibrio cholerae o139 o-antigen polysaccharide is essential for ca2+-dependent biofilm development in sea water. | vibrio cholerae is both an inhabitant of estuarine environments and the etiologic agent of the diarrheal disease cholera. previous work has demonstrated that v. cholerae forms both an exopolysaccharide-dependent biofilm and a ca2+-dependent biofilm. in this work, we demonstrate a role for the o-antigen polysaccharide of v. cholerae in ca2+-dependent biofilm development in model and true sea water. interestingly, v. cholerae biofilms, as well as the biofilms of several other vibrio species, disin ... | 2003 | 14614140 |
| phylogenetic and biochemical evidence for sterol synthesis in the bacterium gemmata obscuriglobus. | sterol biosynthesis is viewed primarily as a eukaryotic process, and the frequency of its occurrence in bacteria has long been a subject of controversy. two enzymes, squalene monooxygenase and oxidosqualene cyclase, are the minimum necessary for initial biosynthesis of sterols from squalene. in this work, 19 protein gene sequences for eukaryotic squalene monooxygenase and 12 protein gene sequences for eukaryotic oxidosqualene cyclase were compared with all available complete and partial prokaryo ... | 2003 | 14660793 |
| novel pathway of salicylate degradation by streptomyces sp. strain wa46. | a novel salicylate-degrading streptomyces sp., strain wa46, was identified by uv fluorescence on solid minimal medium containing salicylate; trace amounts of gentisate were detected by high-pressure liquid chromatography when strain wa46 was grown with salicylate. pcr amplification of wa46 dna with degenerate primers for gentisate 1,2-dioxygenase (gdo) genes produced an amplicon of the expected size. sequential pcr with nested gdo primers was then used to identify a salicylate degradation gene c ... | 2004 | 15006746 |
| molecular analysis of muskelin identifies a conserved discoidin-like domain that contributes to protein self-association. | muskelin is an intracellular protein with a c-terminal kelch-repeat domain that was initially characterized as having functional involvement in cell spreading on the extracellular matrix glycoprotein thrombospondin-1. as one approach to understanding the functional properties of muskelin, we have combined bioinformatic and biochemical studies. through analysis of a new dataset of eight animal muskelins, we showed that the n-terminal region of the polypeptide corresponds to a predicted discoidin- ... | 2004 | 15084145 |
| bacterial signal transduction network in a genomic perspective. | bacterial signalling network includes an array of numerous interacting components that monitor environmental and intracellular parameters and effect cellular response to changes in these parameters. the complexity of bacterial signalling systems makes comparative genome analysis a particularly valuable tool for their studies. comparative studies revealed certain general trends in the organization of diverse signalling systems. these include (i) modular structure of signalling proteins; (ii) comm ... | 2004 | 15142243 |
| conservation of functional domain structure in bicarbonate-regulated "soluble" adenylyl cyclases in bacteria and eukaryotes. | soluble adenylyl cyclase (sac) is an evolutionarily conserved bicarbonate sensor. in mammals, it is responsible for bicarbonate-induced, camp-dependent processes in sperm required for fertilization and postulated to be involved in other bicarbonate- and carbon dioxide-dependent functions throughout the body. among eukaryotes, sac-like cyclases have been detected in mammals and in the fungi dictyostelium; these enzymes display extensive similarity extending through two cyclase catalytic domains a ... | 2004 | 15322879 |
| cloning, sequencing, and functional analysis of an iterative type i polyketide synthase gene cluster for biosynthesis of the antitumor chlorinated polyenone neocarzilin in "streptomyces carzinostaticus". | neocarzilins (nczs) are antitumor chlorinated polyenones produced by "streptomyces carzinostaticus" var. f-41. the gene cluster responsible for the biosynthesis of nczs was cloned and characterized. dna sequence analysis of a 33-kb region revealed a cluster of 14 open reading frames (orfs), three of which (orf4, orf5, and orf6) encode type i polyketide synthase (pks), which consists of four modules. unusual features of the modular organization is the lack of an obvious acyltransferase domain on ... | 2004 | 15328113 |
| origin of asymmetry in adenylyl cyclases: structures of mycobacterium tuberculosis rv1900c. | rv1900c, a mycobacterium tuberculosis adenylyl cyclase, is composed of an n-terminal alpha/beta-hydrolase domain and a c-terminal cyclase homology domain. it has an unusual 7% guanylyl cyclase side-activity. a canonical substrate-defining lysine and a catalytic asparagine indispensable for mammalian adenylyl cyclase activity correspond to n342 and h402 in rv1900c. mutagenic analysis indicates that these residues are dispensable for activity of rv1900c. structures of the cyclase homology domain, ... | 2005 | 15678099 |
| characterization of a recombinant type ii 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase from helicobacter pylori. | dah7p (3-deoxy-d-arabino-heptulosonate 7-phosphate) synthase catalyses the condensation reaction between phosphoenolpyruvate (pep) and d-erythrose 4-phosphate (e4p) as the first committed step in the biosynthesis of aromatic compounds in plants and micro-organisms. previous work has identified two families of dah7p synthases based on sequence similarity and molecular mass, with the majority of the mechanistic and structural studies being carried out on the type i paralogues from escherichia coli ... | 2005 | 15853768 |
| an adenylyl cyclase, cyab, acts as an osmosensor in myxococcus xanthus. | we have previously reported that a receptor-type adenylyl cyclase (cyaa) of myxococcus xanthus undergoes an osmosensor mainly during spore germination (y. kimura et al., j. bacteriol. 184:3578-3585, 2002). in the present study, we cloned another receptor-type adenylyl cyclase gene (cyab) and characterized the function of the cyab-encoded protein. disruption of cyab generates a mutant that showed growth retardation at high ionic (nacl) or high nonionic (sucrose) osmolarity. when vegetative cells ... | 2005 | 15866951 |
| polyketide synthase gene responsible for citrinin biosynthesis in monascus purpureus. | citrinin produced by aspergillus, penicillium, and monascus species is a polyketide compound that has nephrotoxic activity in mammals and is bactericidal toward gram-positive bacteria. to avoid the risk of citrinin contamination in other fermentation products produced by monascus purpureus, knowledge of the citrinin biosynthetic genes is needed so that citrinin-nonproducing strains can be generated. we cloned a polyketide synthase (pks) gene from m. purpureus with degenerate primers designed to ... | 2005 | 16000748 |
| evolution of the acyl-coa binding protein (acbp). | acyl-coa-binding protein (acbp) is a 10 kda protein that binds c12-c22 acyl-coa esters with high affinity. in vitro and in vivo experiments suggest that it is involved in multiple cellular tasks including modulation of fatty acid biosynthesis, enzyme regulation, regulation of the intracellular acyl-coa pool size, donation of acyl-coa esters for beta-oxidation, vesicular trafficking, complex lipid synthesis and gene regulation. in the present study, we delineate the evolutionary history of acbp t ... | 2005 | 16018771 |
| characterization of a small heat shock protein, mx hsp16.6, of myxococcus xanthus. | a number of heat shock proteins in myxococcus xanthus were previously identified by two-dimensional (2d) gel electrophoresis. one of these protein was termed mx hsp16.6, and the gene encoding mx hsp16.6 was isolated. mx hsp16.6 consists of 147 amino acid residues and has an estimated molecular weight of 16,642, in accordance with the apparent molecular mass in the 2d gel. an alpha-crystallin domain, typically conserved in small heat shock proteins, was found in mx hsp16.6. mx hsp16.6 was not det ... | 2005 | 16030217 |
| localization of polyketide synthase encoding genes to the toxic dinoflagellate karenia brevis. | karenia brevis is a toxic marine dinoflagellate endemic to the gulf of mexico. blooms of this harmful alga cause fish kills, marine mammal mortalities and neurotoxic shellfish poisonings. these harmful effects are attributed to a suite of polyketide secondary metabolites known as the brevetoxins. the carbon framework of all polyketides is assembled by a polyketide synthase (pks). previously, pks encoding genes were amplified from k. brevis culture and their similarity to a pks gene from the clos ... | 2005 | 16051286 |
| metagenomic analysis reveals diverse polyketide synthase gene clusters in microorganisms associated with the marine sponge discodermia dissoluta. | sponge-associated bacteria are thought to produce many novel bioactive compounds, including polyketides. pcr amplification of ketosynthase domains of type i modular polyketide synthases (pks) from the microbial community of the marine sponge discodermia dissoluta revealed great diversity and a novel group of sponge-specific pks ketosynthase domains. metagenomic libraries totaling more than four gigabases of bacterial genomes associated with this sponge were screened for type i modular pks gene c ... | 2005 | 16085882 |
| structure and biosynthesis of the bt peptide antibiotic from brevibacillus texasporus. | we isolated a novel gram-positive bacterium, brevibacillus texasporus, that produces an antibiotic, bt. bt is a group of related peptides that are produced by b. texasporus cells in response to nutrient limitation. we report here purification and determination of the structure of the most abundant bt isomer, bt1583. amino acid composition and tandem mass spectrometry experiments yielded a partial bt1583 structure. the presence of ornithine and d-form residues in the partial bt1583 structure indi ... | 2005 | 16332843 |
| 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 ... | 2006 | 16484181 |
| regulation of prokaryotic adenylyl cyclases by co2. | the slr1991 adenylyl cyclase of the model prokaroyte synechocystis pcc 6803 was stimulated 2-fold at 20 mm total c(i) (inorganic carbon) at ph 7.5 through an increase in k(cat). a dose response demonstrated an ec50 of 52.7 mm total c(i) at ph 6.5. slr1991 adenylyl cyclase was activated by co2, but not by hco3-. co2 regulation of adenylyl cyclase was conserved in the cyab1 adenylyl cyclase of anabaena pcc 7120. these adenylyl cyclases represent the only identified signalling enzymes directly acti ... | 2006 | 16573521 |
| yersiniabactin production by pseudomonas syringae and escherichia coli, and description of a second yersiniabactin locus evolutionary group. | the siderophore and virulence factor yersiniabactin is produced by pseudomonas syringae. yersiniabactin was originally detected by high-pressure liquid chromatography (hplc); commonly used pcr tests proved ineffective. yersiniabactin production in p. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. three similarly divergent yersiniabactin locus groups were determined: the yersinia pestis group, the p. syringae group, and the photorhabdus luminescens gr ... | 2006 | 16751485 |
| steroids, triterpenoids and molecular oxygen. | there is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. thus, the detection of steroid and triterpenoid hydrocarbons far back in earth history has been used to infer the antiquity of oxygenic photosynthesis. this prompts the question: were these compounds produced similarly in the past? in this paper, we address this question with a review of the current state of knowledge surrounding the oxygen requir ... | 2006 | 16754609 |
| rooting the tree of life by transition analyses. | despite great advances in clarifying the family tree of life, it is still not agreed where its root is or what properties the most ancient cells possessed--the most difficult problems in phylogeny. protein paralogue trees can theoretically place the root, but are contradictory because of tree-reconstruction artefacts or poor resolution; ribosome-related and dna-handling enzymes suggested one between neomura (eukaryotes plus archaebacteria) and eubacteria, whereas metabolic enzymes often place it ... | 2006 | 16834776 |
| straight-chain fatty acids are dispensable in the myxobacterium myxococcus xanthus for vegetative growth and fruiting body formation. | inactivation of the mxan_0853 gene blocked the production in myxococcus xanthus of straight-chain fatty acids which otherwise represent 30% of total fatty acids. despite this drastic change in the fatty acid profile, no change in phenotype could be observed, which contrasts with previous interpretations of the role of straight-chain fatty acids in the organism's development. | 2006 | 16855254 |
| activity of rhodobacter sphaeroides rpohii, a second member of the heat shock sigma factor family. | we have identified a second rpoh homolog, rpoh(ii), in the alpha-proteobacterium rhodobacter sphaeroides. primary amino acid sequence comparisons demonstrate that r. sphaeroides rpoh(ii) belongs to a phylogenetically distinct group with rpoh orthologs from alpha-proteobacteria that contain two rpoh genes. like its previously identified paralog, rpoh(i), rpoh(ii) is able to complement the temperature-sensitive phenotype of an escherichia coli sigma(32) (rpoh) mutant. in addition, we show that rec ... | 2006 | 16885439 |
| 3-hydroxy-3-methylglutaryl-coenzyme a (coa) synthase is involved in biosynthesis of isovaleryl-coa in the myxobacterium myxococcus xanthus during fruiting body formation. | isovaleryl-coenzyme a (iv-coa) is the starting unit for some secondary metabolites and iso-odd fatty acids in several bacteria. according to textbook biochemistry, iv-coa is derived from leucine degradation, but recently an alternative pathway that branches from the well-known mevalonate-dependent isoprenoid biosynthesis has been described for myxobacteria. a double mutant was constructed in myxococcus xanthus by deletion of genes involved in leucine degradation and disruption of mvas encoding t ... | 2006 | 16952943 |
| reconstitution of the myxothiazol biosynthetic gene cluster by red/et recombination and heterologous expression in myxococcus xanthus. | although many secondary metabolites exhibiting important pharmaceutical and agrochemical activities have been isolated from myxobacteria, most of these microorganisms remain difficult to handle genetically. to utilize their metabolic potential, heterologous expression methodologies are currently being developed. here, the red/et recombination technology was used to perform all required gene cluster engineering steps in escherichia coli prior to the transfer into the chromosome of the heterologou ... | 2006 | 16997979 |
| structure and biosynthesis of heat-stable antifungal factor (hsaf), a broad-spectrum antimycotic with a novel mode of action. | a screen for antifungal compounds from lysobacter enzymogenes strain c3, a bacterial biological control agent of fungal diseases, has previously led to the isolation of heat-stable antifungal factor (hsaf). hsaf exhibits inhibitory activities against a wide range of fungal species and shows a novel mode of antifungal action by disrupting the biosynthesis of a distinct group of sphingolipids. we have now determined the chemical structure of hsaf, which is identical to that of dihydromaltophilin, ... | 2007 | 17074795 |
| structure and biosynthesis of heat-stable antifungal factor (hsaf), a broad-spectrum antimycotic with a novel mode of action. | a screen for antifungal compounds from lysobacter enzymogenes strain c3, a bacterial biological control agent of fungal diseases, has previously led to the isolation of heat-stable antifungal factor (hsaf). hsaf exhibits inhibitory activities against a wide range of fungal species and shows a novel mode of antifungal action by disrupting the biosynthesis of a distinct group of sphingolipids. we have now determined the chemical structure of hsaf, which is identical to that of dihydromaltophilin, ... | 2007 | 17074795 |
| aggregation during fruiting body formation in myxococcus xanthus is driven by reducing cell movement. | when starved, myxococcus xanthus cells assemble themselves into aggregates of about 10(5) cells that grow into complex structures called fruiting bodies, where they later sporulate. here we present new observations on the velocities of the cells, their orientations, and reversal rates during the early stages of fruiting body formation. most strikingly, we find that during aggregation, cell velocities slow dramatically and cells orient themselves in parallel inside the aggregates, while later cel ... | 2007 | 17098901 |
| aggregation during fruiting body formation in myxococcus xanthus is driven by reducing cell movement. | when starved, myxococcus xanthus cells assemble themselves into aggregates of about 10(5) cells that grow into complex structures called fruiting bodies, where they later sporulate. here we present new observations on the velocities of the cells, their orientations, and reversal rates during the early stages of fruiting body formation. most strikingly, we find that during aggregation, cell velocities slow dramatically and cells orient themselves in parallel inside the aggregates, while later cel ... | 2007 | 17098901 |
| new locus important for myxococcus social motility and development. | the mts locus in salt-tolerant myxococcus fulvus hw-1 was found to be critical for gliding motility, fruiting-body formation, and sporulation. the homologous genes in myxococcus xanthus are also important for social motility and fruiting-body development. the mts genes were determined to be involved in cell-cell cohesion in both myxobacterial species. | 2007 | 17720782 |
| biosynthesis of the earthy odorant geosmin by a bifunctional streptomyces coelicolor enzyme. | geosmin is responsible for the characteristic odor of moist soil, as well as off-flavors in drinking water and foodstuffs. geosmin is generated from farnesyl diphosphate (fpp, 2) by an enzyme that is encoded by the sco6073 gene in the soil organism streptomyces coelicolor a32 (ref. 3). we have now shown that the recombinant n-terminal half of this protein catalyzes the mg2+-dependent cyclization of fpp to germacradienol and germacrene d, while the highly homologous c-terminal domain, previously ... | 2007 | 17873868 |
| identification of opda, a gene involved in biodegradation of the endocrine disrupter octylphenol. | octylphenol (op) is an estrogenic detergent breakdown product. structurally similar nonylphenols are transformed via type ii ispo substitution, resulting in the production of hydroquinone and removal of the branched side chain. nothing is known, however, about the gene(s) encoding this activity. we report here on our efforts to clone the gene(s) encoding op degradation activity from sphingomonas sp. strain pwe1, which we isolated for its ability to grow on op. a fosmid library of pwe1 dna yielde ... | 2007 | 17890335 |
| evolution and functional characterization of the rh50 gene from the ammonia-oxidizing bacterium nitrosomonas europaea. | the family of ammonia and ammonium channel proteins comprises the amt proteins, which are present in all three domains of life with the notable exception of vertebrates, and the homologous rh proteins (rh50 and rh30) that have been described thus far only in eukaryotes. the existence of an rh50 gene in bacteria was first revealed by the genome sequencing of the ammonia-oxidizing bacterium nitrosomonas europaea. here we have used a phylogenetic approach to study the evolution of the n. europaea r ... | 2007 | 17921289 |
| spatial organization of myxococcus xanthus during fruiting body formation. | microcinematography was used to examine fruiting body development of myxococcus xanthus. wild-type cells progress through three distinct phases: a quiescent phase with some motility but little aggregation (0 to 8 h), a period of vigorous motility leading to raised fruiting bodies (8 to 16 h), and a period of maturation during which sporulation is initiated (16 to 48 h). fruiting bodies are extended vertically in a series of tiers, each involving the addition of a cell monolayer on top of the upp ... | 2007 | 17921303 |
| dynamic surface activity of a fully synthetic phospholipase-resistant lipid/peptide lung surfactant. | this study examines the surface activity and resistance to phospholipase degradation of a fully-synthetic lung surfactant containing a novel diether phosphonolipid (depn-8) plus a 34 amino acid peptide (mini-b) related to native surfactant protein (sp)-b. activity studies used adsorption, pulsating bubble, and captive bubble methods to assess a range of surface behaviors, supplemented by molecular studies using fourier transform infrared (ftir) spectroscopy, circular dichroism (cd), and plasmon ... | 2007 | 17940603 |
| bioinformatics and experimental analysis of proteins of two-component systems in myxococcus xanthus. | proteins of two-component systems (tcs) have essential functions in the sensing of external and self-generated signals in bacteria and in the generation of appropriate output responses. accordingly, in myxococcus xanthus, tcs are important for normal motility and fruiting body formation and sporulation. here we analyzed the m. xanthus genome for the presence and genetic organization of genes encoding tcs. two hundred seventy-two tcs genes were identified, 251 of which are not part of che gene cl ... | 2008 | 17993514 |
| bioinformatics and experimental analysis of proteins of two-component systems in myxococcus xanthus. | proteins of two-component systems (tcs) have essential functions in the sensing of external and self-generated signals in bacteria and in the generation of appropriate output responses. accordingly, in myxococcus xanthus, tcs are important for normal motility and fruiting body formation and sporulation. here we analyzed the m. xanthus genome for the presence and genetic organization of genes encoding tcs. two hundred seventy-two tcs genes were identified, 251 of which are not part of che gene cl ... | 2008 | 17993514 |
| expressed sequence tags from the oomycete plasmopara halstedii, an obligate parasite of the sunflower. | sunflower downy mildew is a major disease caused by the obligatory biotrophic oomycete plasmopara halstedii. little is known about the molecular mechanisms underlying its pathogenicity. in this study we used a genomics approach to gain a first insight into the transcriptome of p. halstedii. | 2007 | 18062809 |
| identification of (8s,9s,10s)-8,10-dimethyl-1-octalin, a key intermediate in the biosynthesis of geosmin in bacteria. | | 2008 | 18095691 |
| identification of (8s,9s,10s)-8,10-dimethyl-1-octalin, a key intermediate in the biosynthesis of geosmin in bacteria. | | 2008 | 18095691 |
| geosmin biosynthesis. mechanism of the fragmentation-rearrangement in the conversion of germacradienol to geosmin. | | 2008 | 18095692 |
| geosmin biosynthesis. mechanism of the fragmentation-rearrangement in the conversion of germacradienol to geosmin. | | 2008 | 18095692 |
| social bacteria and asocial eukaryotes. | | 2008 | 18199122 |