| arginine metabolism by spiroplasma citri. | | 1976 | 7639 |
| effect of external environmental factors on the morphology of spiroplasma citri. | spiroplasma citri was examined by electron microscopy for morphological changes when maintained under a variety of conditions. pplo serum fraction maintained spiral and helical morphology of s. citri at ph values of 8.0, 7.5, and 7.0, but only partially at ph 6.0 and 5.0. the absence of pplo serum fraction resulted in round, deteriorated cells at all ph values tested. bovine serum albumin (bsa), phytone, soluble starch, potato starch, spermine, lipid-extracted pplo serum fraction, and lipid-extr ... | 1978 | 24042 |
| effect of osmotic potential, ph, and temperature on the growth of a helical, motile mycoplasma causing corn stunt disease. | growth characteristics of corn stunt spiroplasma, a helical, motile mycoplasma, were studied over a range of osmolality, ph, and temperature in a simple medium containing 20% (v/v) agamma horse serum, 1.5% (w/v) pplo broth, and various concentrations of sucrose. the spiroplasma was able to grow in a wide spectrum of osmolalities from 360 to 1120 mosm. optimal growth was observed in media that contained 0.25-0.35 m sucrose. the organism became longer and thinner in media adjusted to 0.65 m sucros ... | 1978 | 25704 |
| 2nd conference of the international organization for mycoplasmology (iom) august 28--september 1, 1978 in freiburg i. br. 1. symposium: "molecular biology of mycoplasmas". abstracts. | | 1978 | 31747 |
| separation and partial characterization of two deoxyribonucleic acid polymerases from spiroplasma citri. | the separation and partial characterization of two deoxyribonucleic acid polymerases from spiroplasma citri have been achieved. the two enzymes had different elution properties on diethylaminoethyl (deae) cellulose and differed in their sensitivity to n-ethylmaleimide (nem), preference for different template-primers, and sedimentation velocity in linear glycerol gradients. the first enzyme activity, sca, was retained on deae-cellulose and was not inhibited by nem. activated deoxyribonucleic acid ... | 1979 | 42638 |
| an in vitro comparison of some biochemical and biological properties of california and morocco isolates of spiroplasma citri. | | 1979 | 43764 |
| the pathogenicity of mycoplasmas for plants. | many plant diseases belonging to the yellows group are believed to be caused by wall-free prokaryotes resembling mycoplasmas, which are spread by leafhopper vectors. im most cases the evidence for mycoplasma aetiology rests upon the finding by electron microscopy of mycoplasma-like bodies in phloem tissue of diseased plants, coupled in some cases with symptom remission following treatment of plants with tetracyclines. the only plant-pathogenic mycoplasmas which have so far been cultured are the ... | 1979 | 44613 |
| pathogenicity of mycoplasmas for arthropods. | | 1979 | 44614 |
| spiroplasmas: serological grouping of strains associated with plants and insects. | spiroplasma strains from plant and arthropod hosts, and from surfaces of flowers, were classified into three serological groups (designated i, ii, and iii) based on results from growth-inhibition tests. no significant cross reactions were observed among groups. the groupings were confirmed by ring-interface precipitin and microprecipitin tests, using membrane preparations as test antigens, and by organism-deformation tests. serogroup i contained three subgroups: subgroup a (spiroplasma citri str ... | 1979 | 93504 |
| gliding mycoplasmas are inhibited by cytochalasin b and contain a polymerizable protein fraction. | studies are presented on the effect of cytochalasin b (cb) on the growth of five mycoplasma species, three acholeplasma species, and one spiroplasma species. the three gliding mycoplasma species (m gallisepticum, m pneumoniae and m pulmonis are the only mycoplasmas inhibited by cb. these are the only prokaryotes reported to be inhibited by cb. this suggested that these three mycoplasmas might have some sort of cytoskeletal structure. a protein fraction has been isolated from m gallisepticum whic ... | 1979 | 121144 |
| carbohydrate content and enzymic activites in the membrane of spiroplasma citri. | | 1977 | 142817 |
| composition and enzyme activities of spiroplasma citri membranes. | spiroplasma citri was cultured in three different media that supplied cholesterol and fatty acids from: (i) horse serum, (ii) pleuropneumonia-like organism (pplo) serum fraction, or (iii) bovine serum albumin-fatty acid-cholesterol. the ability of pplo serum fraction to support growth varied by lot number. neither pplo serum fraction nor the bovine serum albumin medium supported growth as well as the horse serum medium. analysis of cholesterol, lipid phosphorus, and membrane protein showed the h ... | 1977 | 191432 |
| viruses of mycoplasmas and spiroplasmas. | | 1977 | 324253 |
| age and evolution of bacteria. | | 1977 | 330208 |
| simplified preparation of mycoplasmas, an acholeplasma, and a spiroplasma for scanning electron microscopy. | a simple, effective procedure was developed for scanning electron microscopic examination of mycoplasmas and similar organisms. cultivation of several mycoplasmal species, an acholeplasma, and a spiroplasma in broth media in leighton tubes with cover slips resulted in attachment of the organisms to the cover slips. the attached cells were easily processed for either scanning electron microscopy or light microscopy. by eliminating the need for centrifugation, which was used in previously describe ... | 1979 | 370106 |
| enhanced isolation of mycoplasma pneumoniae from throat washings with a newly-modified culture medium. | two hundred throat washings, previously screened and presumed negative for mycoplasma pneumoniae in conventional mycoplasma culture media, were retested for the organism in a modified medium (ps-4) initially developed for cultivation of a tick-derived mycoplasma (spiroplasma). the organism was rapidly identified with an agar plate immunofluorescence procedure. m. pneumoniae was isolated from 69 (34.5%) of the 200 "negative" specimens cultured on a diphasic sp-4 medium, in contrast to 10 isolatio ... | 1979 | 374649 |
| spiroplasma-like inclusions in creutzfeldt-jakob disease. | spiral membranous inclusions were discovered on electron microscopic study of brain biopsy tissues from a 46-year-old man with creutzfeldt-jakob disease (cjd). these replicate coiled membranous configurations measured 850 to 1,000 nm in length and 75 to 137.5 nm in width and were located within axoplasm, primarily in presynaptic terminals. these inclusions closely resemble spiroplasma, a plant pathogen, and the finding of these structures in cjd suggests the concurrence of spiroplasma infection ... | 1979 | 389196 |
| lipoquinones of some bacteria and mycoplasmas, with considerations on their functional significance. | in a comparative study the lipoquinones of some chemoorganotrophic, facultatively aerobic bacteria, and representative acholeplasma, mycoplasma, spiroplasma, and thermoplasma strains were investigated. the quinones were partly purified by preparative thin layer chromatography of lipid extracts, and characterized by their difference spectra (reduced minus oxidized) and rf values. respiring bacteria expectedly contained benzoquinones and/or naphthoquinones in micromolar concentrations whereas some ... | 1977 | 413478 |
| comparison of the membrane composition of spiroplasma citri and the corn stunt spiroplasma. | components of membranes isolated from spiroplasma citri and corn stunt spiroplasma grown at 28 degrees c were analyzed. on a protein basis, lipid phosphorus was lower and cholesterol was higher in s. citri. only minor differences between the two species were found in fatty acid composition, reduced nicotinamide adenine dinucleotide diaphorase, and adenosine triphosphatase. | 1979 | 422510 |
| amphilphilic nature of spiralin, the major protein of the spiroplasma citri cell membrane. | spiralin could not be solubilized in the absence of detergents, and it was shown by charge-shift crossed immunoelectrophoresis that this protein was capable of binding detergents under nondenaturing conditions. these properties indicate the amphiphilic nature of spiralin, which therefore should be regarded as an intrinsic membrane protein. the efficiency of mild (ionic and neutral) detergents to solubilize spiralin was as follows: deoxycholate greater than lauroyl sarcosinate, cholate, taurochol ... | 1979 | 500570 |
| [electron microscopical evidence of spiroplasma citri in nucleus of infected testplants (author's transl)]. | this is the first report for the evidence of mycoplasmas in an organelle of a plant cell. spiroplasma citri was detected by electron microscopy in the nucleus of a phloem parenchyma cell of chrysanthemum carinatum schousboe plants, inoculated experimentally by euscelis plebejus fall. | 1979 | 549392 |
| high concentrations of horse serum inhibit growth of corn stunt spiroplasma. | corn stunt spiroplasma (css) grew faster and achieved higher titers in liquid or agar medium containing 5 or 10 percent horse serum than it did in medium containing 20 percent horse serum. when growth in liquid medium was initiated with a small inoculum, css achieved excellent growth in the presence of 5 percent serum but did not grow in medium containing 0 or 20 percent serum. addition of arginine to liquid or agar medium supplemented with 20 percent serum stimulated css growth, but addition to ... | 1978 | 564163 |
| solubilization of spiroplasma citri cell membrane proteins with the anionic detergent sodium lauroyl-sarcosinate (sarkosyl). | 1. up to 90 per cent of the membrane proteins from spiroplasma citri could be solubilized with the anionic detergent sarkosyl (sodium lauroyl-sarcosinate). maximal solubilization was obtained with 6 to 20 mumoles of of detergent per mg of membrane protein. the insoluble residue, comprising about 10 per cent of the membrane protein, contained mainly the protein spiralin, which is quantitatively the major one of this membrane. 2. mg2+ ions completely prevented solubilization of the membrane protei ... | 1978 | 687677 |
| spiroplasma associated with flowers of the tulip tree (liriodendron tulipifera l.). | spiroplasmas were isolated and cultivated from nonsurface-sterilized petals and bracts excised from flowers of liriodendron tulipifera l. (tulip tree) in anne arundel, charles, and prince george's counties in maryland, and east lyme county, connecticut. all isolates grew at 30 and at 37 degrees c. morphology of colonies on solid agar (1%) medium containing serum differed among isolates: some isolates formed highly diffuse, barely visible colonies; others formed distinct colonies with granular ce ... | 1978 | 688103 |
| comparison of lipids from spiroplasma citri and corn stunt spiroplasma. | the qualitative lipid composition of spiroplasma citri and corn stunt spiroplasma is identical. small amounts of acylated glucose and steryl glucoside were found. | 1978 | 711681 |
| pathogenic mycoplasmas: cultivation and vertebrate pathogenicity of a new spiroplasma. | a spiroplasma recovered from allantoic fluids of chick embryos infected with the tick-derived suckling mouse cataract agent was grown in continuous passage on a new artificial culture medium. the cultured organisms induced typical ocular and other disease symptoms in susceptible animals, and were reisolated from involved host tissues. although spiroplasmas have been previously recognized as plant and insect pathogens, this is the first spiroplasma shown to multiply at 37 degrees c and to be path ... | 1977 | 841314 |
| mycoplasma-dependent activation of normal lymphocytes: mitogenic potential of mycoplasmas for mouse lymphocytes. | nonviable preparations of a wide variety of glucose-utilizing mycoplasma species, including acholeplasma laidlawii and spiroplasma citri, were found to be mitogenic for mouse lymphocytes. particularly strong reactions were obtained with mycoplasma synoviae, m. gallisepticum, m. pneumoniae, s. citri, and a strain of m. fermentans that was previously isolated from a leukemic patient. nonviable preparations of arginine-utilizing mycoplasmas inhibited the uptake of [3h]thymidine by lymphocytes, but ... | 1977 | 924676 |
| spiroplasmavirus citri 3: propagation, purification, proteins, and nucleic acid. | svc3 is a short-tailed polyhedral virus particle morphologically detectable in many spiroplasmas. it was isolated from two different spiroplasmas (spiroplasma citri and the suckling mouse cataract agent) by infecting lawns and broth culture of another strain of spiroplasmavirus citri. virions from either donor strain had a buoyant density of 1.26 grams per cubic centimeter (metrizamide) or 1.45 grams per cubic centimeter (cesium chloride), and contained five proteins and linear double-stranded d ... | 1977 | 929198 |
| in vitro anti-mycoplasmal activity of amphotericin b methyl ester. | the polyene macrolide antibiotic amphotericin b (ab) and its chemically modified derivative amphotericin b methyl ester (ame) were tested for in vitro activity against acholeplasma laidlawii, spiroplasma citri and mycoplasma gallisepticum. both polyene macrolide preparations demonstrated anti-mycoplasmal activity. however, ame was mycoplasmacidal toward all three strains of mycoplasma at levels which previous studies have indicated would be permissible for most cell culture systems, whereas the ... | 1976 | 950321 |
| helical wall-free prokaryotes in insects: multiplication and pathogenicity. | | 1975 | 1072598 |
| ocular pathology induced by the suckling mouse cataract agent. | the eye disease caused by smca may be best characterized as an endophthalmitis, with early retinitis followed by subsequent posterior uveitis. pathologic features of lens included: proliferation and abnormal posterior extension of lens epithelium, increased accumulation of lens capsule material, and production of aberrant lens substance. cataractous change appears to be secondary to intraocular inflammation. in addition to the above pattern, in roughly 20 per cent of all cases, 3 weeks after ino ... | 1976 | 1085291 |
| [selective solubilization of spiroplasma citri membrane proteins with sodium desoxycholate]. | | 1975 | 1222145 |
| suckling mouse cataract agent is a helical wall-free prokaryote (spiroplasma) pathogenic for vertebrates. | | 1976 | 1246348 |
| distribution and composition of lipopolysaccharides from mycoplasmas. | polymeric carbohydrates containing glycerol and fatty acids were isolated from whole cells and membranes of mycoplasmas by hot aqueous phenol extraction and gel filtration. lipopolysaccharides were found to occur in four species of acholeplasma, two of anaeroplasma, and in mycoplasma neurolyticum. none were detected in spiroplasma citri or in five species of mycoplasma. all lipopolysaccharides contained both neutral and n-acylated amino sugars in ratios varying from 1:1 to 3:1. the neutral sugar ... | 1976 | 1254559 |
| lipid composition and lipid metabolism of spiroplasma citri. | in a horse serum-based medium containing a full complement of fatty acids, cells of spiroplasma citri were seen to preferentially incorporate palmitic acid. in the same medium, which had a steryl ester-to-sterol ratio of 3.64, a steryl ester-to-sterol ratio of 0.23 was seen in the cells, cholesterol being preferentially incorporated over cholesteryl ester. like most other mycoplasmas, s. citri was shown to be unable to synthesize fatty acids or esterify cholesterol. the neutral lipids of s. citr ... | 1976 | 1254560 |
| detection by pcr and differentiation by restriction fragment length polymorphism of acholeplasma, spiroplasma, mycoplasma, and ureaplasma, based upon 16s rrna genes. | | 1992 | 1282069 |
| cloning and sequencing of is1086, an alcaligenes eutrophus insertion element related to is30 and is4351. | a new insertion sequence (is), designated is1086, was isolated from alcaligenes eutrophus ch34 by being trapped in plasmid pjv240, which contains the bacillus subtilis sacb and sacr genes. the 1,106-bp is1086 element contains partially matched (22 of 28 bp) terminal-inverted repeats and a long open reading frame. hybridization data suggest the presence of one copy of is1086 in the strain ch34 heavy-metal resistance plasmid pmol28 and at least two copies in its chromosome. analysis of the is1086 ... | 1992 | 1334071 |
| a physical and genetic map of the spiroplasma citri genome. | a physical and genetic map of the spiroplasma citri genome has been constructed using several restriction enzymes and pulsed field gel electrophoresis. a number of genes were subsequently localized on the map by the use of appropriate probes. the genome size of the spiroplasma estimated from restriction fragments is close to 1780 kbp, the largest of all mollicutes studied so far. it contains multisite insertions of spiroplasma virus 1 (spv1) sequences. the physical and genetic map of the s. citr ... | 1992 | 1349741 |
| genus- and species-specific identification of mycoplasmas by 16s rrna amplification. | systematic computer alignment of mycoplasmal 16s rrna sequences allowed the identification of variable regions with both genus- and species-specific sequences. species-specific sequences of mycoplasma collis were elucidated by asymmetric amplification and dideoxynucleotide sequencing of variable regions, using primers complementary to conserved regions of 16s rrna. primers selected for mycoplasma pneumoniae, m. hominis, m. fermentans, ureaplasma urealyticum, m. pulmonis, m. arthritidis, m. neuro ... | 1992 | 1381174 |
| spiroplasma citri ugg and uga tryptophan codons: sequence of the two tryptophanyl-trnas and organization of the corresponding genes. | from the total trnas of spiroplasma citri, we isolated and purified two trna(trp) species by using chromatography on an rpc-5 column followed by denaturing polyacrylamide gel electrophoresis. the sequence of the two trnas, as well as the sequences of the corresponding genes, were determined. one of the two trna(trp) species has a cca anticodon and is able to pair with the universal ugg tryptophan codon, while the second has a u*ca (u* is a modified uridine) anticodon and is able to pair with uga ... | 1992 | 1383193 |
| [mollicute acholeplasma florum possesses a gene of phosphoenolpyruvate sugar phosphotransferase system and it uses uga as tryptophan codon]. | acholeplasmas are mollicutes which do not require sterol for growth and do not possess a phosphoenolpyruvate-dependent sugar-phosphotransferase system. in contrast to spiroplasmas, mycoplasmas and ureaplasmas, they utilize uga as a stop codon and not as a tryptophan codon. acholeplasma florum, because of its metabolic properties and its close phylogenetic relationship to members of the genera spiroplasma and mycoplasma, does not seem to be an acholeplasma senso stricto. here, we present molecula ... | 1992 | 1422919 |
| mode of action of the spiroplasma cpg methylase m.sssi. | the cytosine dna methylase from the wall-less prokaryote, spiroplasma strain mq1 (m.sssi) methylates completely and exclusively cpg-containing sequences, thus showing sequence specificity which is similar to that of mammalian dna methylases. m.sssi is shown here to methylate duplex dna processively as judged by kinetic analysis of methylated intermediates. the cytosine dna methylases, m.hpaii and m.hhai, from other prokaryotic organisms, appear to methylate in a non-processive manner or with a v ... | 1992 | 1446743 |
| [spiroplasma from tabanidae capable to multiply and to persist in the central nervous system in mice]. | using alternate passages of cultivation in vitro at 37 degrees c and in suckling mice following intracerebral inoculation, a tabanid spiroplasma was demonstrated capable of multiplication and persistence in mice for 6 successive passages, without production of specific antibody. this is the first report of a spiroplasma from a common flying haematophagous arthropod shown to produce persistent infection of a mammal. | 1992 | 1468026 |
| uptake of a fluorescent-labeled fatty acid by spiroplasma floricola cells. | 12-(1-pyrene)dodecanoic fatty acid (p12) uptake by spiroplasma floricola bnr-1 cells was characterized with regard to its kinetics, specificity, metabolism and susceptibility to protein and lipid inhibitors. the uptake process depended on temperature and ph, and exhibited biphasic saturation kinetics with a very low (2.7 microm) and a high (37 microm) apparent km value. lauric, myristic, palmitic, stearic and oleic fatty acids did not compete with p12 for transport. the fluorescence of p12 was e ... | 1992 | 1510559 |
| mutagenesis of a tryptophan codon from tgg to tga in the cat gene does not prevent its expression in the helical mollicute spiroplasma citri. | | 1992 | 1544572 |
| fusion-mediated transfer of plasmids into spiroplasma floricola cells. | we have developed and characterized a system for the transfer of plasmids encapsulated in large unilamellar vesicles (luv) into spiroplasma floricola bnr1 cells. the approach is based on the ability of s. floricola-derived luv to fuse with s. floricola cells. the fusion was continuously monitored by an assay for lipid mixing based on the dequenching of the fluorescent probe octadecylrhodamine b (r18) that was incorporated into luv at self-quenching concentrations. the fusion was also evaluated b ... | 1992 | 1624433 |
| [basic research on the use of mosquito spiroplasmas in the control of the major tropical diseases transmitted by mosquitoes]. | an increasing number of experimental findings suggest that spiroplasma taiwanense (class mollicutes) has considerable potential for inclusion in integrated mosquito vector control programmes. these experimental findings are outlined in conjunction with preferred strategies for its eventual use as a biological control agent. | 1991 | 1687886 |
| antigenic relatedness between the spiralins of spiroplasma citri and spiroplasma melliferum. | four spiralins were compared by rocket immunoelectrophoresis, quantitative immunoblotting techniques, and the spiroplasma deformation test with the use of antispiralin (polyclonal) monospecific antibodies. this investigation revealed that the spiralins of spiroplasma citri and s. melliferum are antigenically related and that probably no more than two epitopes simultaneously saturable with antibodies are shared by the two proteins. one at least of these epitopes is accessible to antibodies on the ... | 1990 | 1697579 |
| first step toward a virus-derived vector for gene cloning and expression in spiroplasmas, organisms which read uga as a tryptophan codon: synthesis of chloramphenicol acetyltransferase in spiroplasma citri. | spiroplasmas are wall-less procaryotes in which the uga codon serves not as a stop signal but as a code for the amino acid tryptophan. spiroplasma genes that contain uga codons thus cannot be studied in the usual escherichia coli cloning and expression systems. although this problem can be circumvented by using uga-suppressor strains of e. coli, spiroplasmas themselves would provide a more efficient cloning and expression host. we have now successfully employed the replicative form (rf) of a fil ... | 1991 | 1706702 |
| nucleotide sequence of the spiroplasma citri fibril protein gene. | electron microscopic observation of spiroplasmas lysed by detergent (sodium deoxycholate) revealed the release of bundles of fibrils from the cells. individual fibrils are 4 nm in diameter and possess a 9-nm periodicity along their length. these fibrils are thought to function as cytoskeletal structures involved in the shape and motility of spiroplasmas. polyacrylamide gel electrophoresis of density gradient-purified fibrils showed a protein of approximately 55 kda. oligonucleotide probes were c ... | 1991 | 1712358 |
| evolution of trnas and trna genes in acholeplasma laidlawii. | the genes for 22 trna species from acholeplasma laidawii, belonging to the class mollicutes (mycoplasmas), have been cloned and sequenced. sixteen genes are organized in 3 clusters consisting of eleven, three and two trna genes, respectively, and the other 6 genes exist as a single gene. the arrangement of trna genes in the 11-gene, the 3-gene and the 2-gene clusters reveals extensive similarity to several parts of the 21-trna or 16-trna gene cluster in bacillus subtilis. the 11-gene cluster is ... | 1991 | 1722304 |
| spiroplasmas and spongiform encephalopathies. | | 1992 | 1736068 |
| spiroplasmas from european tabanidae. | | 1991 | 1768895 |
| pathogenicity of spiroplasma taiwanense for larval aedes aegypti mosquitoes. | helical replicative forms, but not the persistent non-replicative forms, of spiroplasma taiwanense abalain-colloc et al. (isolated from the mosquito anopheles sinensis wiedemann in taiwan) were shown to reduce significantly the survival of aedes aegypti (l.) mosquito larvae reared in 10 ml of water with 0.3 ml of s.taiwanense suspensions added on days 0 and 3. the suspensions contained, respectively, helical forms at a concentration of 10(9) colour change units (ccu)/ml and persistent forms at 1 ... | 1991 | 1768913 |
| bacterial pyruvate kinases have a shorter n-terminal domain. | the n-terminal portions of the two forms of pyruvate kinase (ec2.7.1.40) from escherichia coli have been sequenced up the 48th and 43rd residue, respectively. comparison with the known primary structures shows that bacterial enzymes lack a substantial portion of the n-terminal sequence with respect to pyruvate kinases from vertebrates. this makes the suggested functional role of the n-terminal domain unlikely [muirhead, h. (1990) biochem. soc. trans. 18, 193-196] although an elongation of this d ... | 1991 | 1859631 |
| search for eukaryotic motility proteins in spirochetes: immunological detection of a tektin-like protein in spirochaeta halophila. | the serial endosymbiotic theory (set) for the spirochete origin of undulipodia (cilia and eukaryotic flagella) predicts that a greater number of axonemal proteins will show homology to spirochete than to other bacterial proteins. to continue testing, the set proteins associated with eukaryotic motility (tektin, centrin and calmodulin) were sought in spirochaeta halophila. western blot immunological detection techniques (for tektin and centrin) and two-dimensional gel analysis (for calmodulin) we ... | 1991 | 1863720 |
| multiplication and persistence of spiroplasma melliferum strain a56 in experimentally infected suckling mice. | strain a56 of the bee pathogen spiroplasma melliferum was isolated from a honeybee (apis mellifera) during ecological studies on mosquito spiroplasmas in savoie (france). when inoculated intracerebrally (i.c.) into 48-h old suckling mice, this strain was found to replicate to very high titres and to persist in brain for up to 9 months in one individual. we attempted to increase the "neurotropism" of a56 by sequential i.c. passages. during the first two passages, multiplication of the organisms w ... | 1991 | 1871426 |
| rheumatoid arthritis: new findings on the failure to isolate or detect mycoplasmas by multiple cultivation or serologic procedures and a review of the literature. | using 12 different and elaborate broth, agar, and cell culture procedures, we failed to isolate mycoplasmas, ureaplasmas, spiroplasmas, or chlamydiae from the synovial fluid of 10 patients with rheumatoid arthritis (ra) and from six patients with non-rheumatoid arthritis (nra). in addition, sera from 35 patients with ra and 12 patients with nra also were examined. although some of the sera had moderately high titers of metabolism-inhibiting antibody to some of the 10 human mycoplasma species, es ... | 1991 | 1925272 |
| fusion of mycoplasmas: the formation of cell hybrids. | poly(ethylene glycol) (peg 8000) can induce cell-cell fusion of mycoplasma capricolum cells, and it can promote the formation of intergeneric hybrids of various mycoplasma, acholeplasma and spiroplasma species. the extent of fusion was quantitatively evaluated by following the dequenching of octadecylrhodamine fluorescent label incorporated into donor cell membranes after their incubation with recipient cells. the results of dequenching experiments were confirmed by electron microscopy, as well ... | 1991 | 1936938 |
| identification and characterization of proteinase k-resistant proteins in members of the class mollicutes. | proteins resistant to proteinase k are rare because of the potency, wide ph optimum, and low peptide bond specificity of this enzyme. previously, only the prion proteins associated with transmissible spongiform encephalopathies, possibly related proteins in the mollicute spiroplasma mirum, and proteinase k itself have been reported. we identified a new proteinase k-resistant protein, p40-pr, in two strains of mycoplasma hyorhinis and in extracts of these organisms. p40-pr's are similar to prion ... | 1991 | 1997407 |
| adenovirus type 2 vai rna transcription by polymerase iii is blocked by sequence-specific methylation. | sequence-specific methylation of the promoter and adjacent regions in mammalian genes transcribed by rna polymerase ii leads to the inhibition of these genes. so far, rna polymerase iii-transcribed genes have not been investigated in depth. we therefore studied methylation effects on the rna polymerase iii-transcribed vai gene of adenovirus type 2 dna. the vai gene contains 20 5'-cg-3' dinucleotides, of which 4 (20%) can be methylated by hpaii (5'-ccgg-3') and hhai (5'-gcgc-3'). three of these 5 ... | 1991 | 2002541 |
| spiroplasma (mollicutes: spiroplasmataceae) pathogenic for aedes aegypti and anopheles stephensi (diptera: culicidae). | intrathoracic inoculation with the mosquito spiroplasma, spiroplasma taïwanense abalain-colloc et al., was found to reduce significantly the survival of adult male and female aedes aegypti (l.) and anopheles stephensi liston. this spiroplasma also reduced significantly the flight capacity of adult female ae. aegypti 5-8 d after inoculation and adult female an. stephensi 4 d after inoculation. adult female an. stephensi were incapable of flight 5 d after inoculation. as such, s. taïwanense joins ... | 1991 | 2056503 |
| [experimental infection of aedes albopictus mosquitoes by a spiroplasma strain isolated from culex annulus in taiwan]. | two aedes albopictus strains are infected by one of the four presently known mosquito spiroplasma strains, the cuas-1 strain isolated from culex annulus from taïwan. an infection by intra-thoracic inoculation leads to a pathogenic effect, dose-dependent, the longevity of mosquitoes being shortened. this pathogenicity is observed at various time after inoculation depending of the mosquito strain. on the other hand, an oral infection has no consequence on the longevity of infected females. however ... | 1991 | 2065400 |
| rickettsial and mollicute infections in hepatopancreatic cells of cultured pacific white shrimp (penaeus vannamei). | infections by multiple species of bacteria occurred in hepatopancreatic epithelial cells of cultured pacific white shrimp (penaeus vannamei). grossly, hepatopancreases of moribund shrimp were pale white. light microscopically, hepatopancreatic tubules appeared atrophied and were associated with granulomas. examination by scanning and transmission electron microscopy revealed heavy cytoplasmic infections by three forms of microorganisms: (1) a rickettsia-like bacterium, (2) a helical form of a mo ... | 1991 | 2066576 |
| partial biochemical characterization of spiroplasma membrane component inducing tumor necrosis factor alpha. | we have recently found that membranes of spiroplasma spp. strain mq-1 (hereafter referred to as mq-1) induce both tumor necrosis factor alpha (tnf alpha) secretion by bone marrow macrophages and blast transformation of lymphocytes via a mechanism different from that operated by bacterial lipopolysaccharide (lps). this report presents evidence indicating that the mq-1-derived membrane component(s) which activates bone marrow macrophages to secrete tnf alpha is, at least in part, protein. this con ... | 1990 | 2131043 |
| organization and nucleotide sequences of the spiroplasma citri genes for ribosomal protein s2, elongation factor ts, spiralin, phosphofructokinase, pyruvate kinase, and an unidentified protein. | the gene for spiralin, the major membrane protein of the helical mollicute spiroplasma citri, was cloned in escherichia coli as a 5-kilobase-pair (kbp) dna fragment. the complete nucleotide sequence of the 5.0-kbp spiroplasmal dna fragment was determined (genbank accession no. m31161). the spiralin gene was identified by the size and amino acid composition of its translational product. besides the spiralin gene, the spiroplasmal dna fragment was found to contain five additional open reading fram ... | 1990 | 2139649 |
| cloning, characterization, and expression in escherichia coli of the gene coding for the cpg dna methylase from spiroplasma sp. strain mq1(m.sssi). | we describe here the cloning, characterization and expression in e. coli of the gene coding for a dna methylase from spiroplasma sp. strain mq1 (m.sssi). this enzyme methylates completely and exclusively cpg sequences. the spiroplasma gene was transcribed in e. coli using its own promoter. translation of the entire message required the use of an opal suppressor, suggesting that uga triplets code for tryptophan in spiroplasma. sequence analysis of the gene revealed several uga triplets, in a 1158 ... | 1990 | 2181400 |
| characterization of a promoter and a transcription terminator of spiroplasma melliferum virus spv4. | spiroplasma virus 4 (spv4) is an isometric virus with single-stranded, circular dna infecting the helical mollicute spiroplasma melliferum, a honeybee pathogen. previous studies in our laboratory led to the determination of the base sequence of the spv4 dna. nine open reading frames and three promoterlike sequences (p1, p2, and p3) were identified. an inverted repeat leading to the formation of a hairpin structure on the transcription product was also found and predicted to be a transcription te ... | 1990 | 2211498 |
| spiralins of spiroplasma citri and spiroplasma melliferum: amino acid sequences and putative organization in the cell membrane. | spiralin is the major membrane protein of the helical mollicute spiroplasma citri. a similar protein occurs in the membrane of spiroplasma melliferum, an organism related to s. citri. the gene encoding spiralin has been sequenced. a restriction fragment of the spiralin gene has been used as a probe to detect the gene encoding s. melliferum spiralin. a 4.6-kilobase-pair clai dna fragment from s. melliferum strongly hybridized with the probe. this fragment was inserted in pbr322 and cloned in esch ... | 1990 | 2211527 |
| sex-ratio biased organisms. | | 1990 | 2215694 |
| mycoplasma lactucae sp. nov., a sterol-requiring mollicute from a plant surface. | strain 831-c4t (t = type strain), isolated from the surface of lettuce plants (lactuca sativa) obtained from a retail food market, was shown to be a sterol-requiring mollicute. morphological examination of this organism by electron and dark-field microscopic techniques showed that it consists of small, nonhelical, nonmotile, pleomorphic coccoid cells, with individual cells surrounded by a single cytoplasmic membrane. no evidence of a cell wall was observed. the organism grew rapidly in all conve ... | 1990 | 2223606 |
| effect of cpg methylation on gene expression in transfected plant protoplasts. | activity of the cat gene driven by the cauliflower mosaic virus 35s promoter has been assayed by transfecting petunia protoplasts with the puc8camvcat plasmid. in vitro methylation of this plasmid with m.hpaii (methylates c in ccgg sites) and m.hhai (methylates gcgc sites) did not affect bacterial chloramphenicol acetyltransferase (cat) activity. it should be noted, however, that no hpaii or hhai sites are present in the promoter sequence. in contrast, in vitro methylation of the plasmid with th ... | 1990 | 2258051 |
| complete nucleotide sequence of the genome of spiroplasma citri virus spv1-r8a2 b. | | 1990 | 2320423 |
| a 57-kilodalton protein associated with spiroplasma melliferum fibrils undergoes reversible phosphorylation. | phosphorylation of a major 57-kilodalton protein substrate was observed in cell lysates of spiroplasma melliferum bc3 incubated with [gamma-32p]atp. only serine phosphates have been isolated from the acid hydrolysate of the phosphorylated protein. the 57-kilodalton protein substrate was found, to a large extent, in the cytosolic fraction and, to a lesser extent, associated with cell membranes and was detected in the triton x-100-insoluble fraction that contained fibrils. | 1990 | 2332410 |
| in vitro induction of tumor necrosis factor alpha, tumor cytolysis, and blast transformation by spiroplasma membranes. | membranes of spiroplasma sp. strain mq-1 (hereafter referred to as mq-1) were potent inducers of tumor necrosis factor alpha (tnf alpha) secretion and of blast transformation. specific anti-recombinant murine tnf alpha antibodies markedly inhibited macrophage-mediated tumor cytolysis of a9 fibrosarcoma target cells following activation by mq-1 membranes. thus, tnf alpha plays a major role in mediation of tumor cytolysis induced by mq-1 membranes, which is similar to its role in lipopolysaccharid ... | 1990 | 2359139 |
| comparative studies to determine the efficiency of 6 methylpurine deoxyriboside to detect cell culture mycoplasmas. | studies were performed to compare three methods to detect mycoplasmal infection of cell cultures. the methods included microbiological assay by inoculation into broth and onto agar with anaerobic incubation, fluorescent dna staining by hoechst 33258, and mycoplasmal mediated cytotoxicity by 6 methylpurine deoxyriboside (6mpdr). fluorescent dna staining and 6mpdr assays were performed in an indicator cell culture system. a total of 2589 cell cultures were assayed. mycoplasmas were detected in 174 ... | 1986 | 2428802 |
| etiologic studies on late-term swine abortions. | one hundred thirty-eight swine abortions were studied in detail in an effort to identify an etiologic agent. a viral agent was implicated in 7 cases. bacteria were isolated in less than half of the examined cases: however, in 61% of the cases, motile, filamentous organisms were observed in tissues and fluids. although swine sera from farms experiencing reproductive problems had a high reactor rate to leptospira bratislava antigen, electron microscopy of the observed organism revealed a wall-free ... | 1989 | 2488334 |
| construction of the mycoplasma evolutionary tree from 5s rrna sequence data. | the 5s rrna sequences of eubacteria and mycoplasmas have been analyzed and a phylogenetic tree constructed. we determined the sequences of 5s rrna from clostridium innocuum, acholeplasma laidlawii, acholeplasma modicum, anaeroplasma bactoclasticum, anaeroplasma abactoclasticum, ureaplasma urealyticum, mycoplasma mycoides mycoides, mycoplasma pneumoniae, and mycoplasma gallisepticum. analysis of these and published sequences shows that mycoplasmas form a coherent phylogenetic group that, with c. ... | 1985 | 2579388 |
| a phylogenetic analysis of the mycoplasmas: basis for their classification. | small-subunit rrna sequences were determined for almost 50 species of mycoplasmas and their walled relatives, providing the basis for a phylogenetic systematic analysis of these organisms. five groups of mycoplasmas per se were recognized (provisional names are given): the hominis group (which included species such as mycoplasma hominis, mycoplasma lipophilum, mycoplasma pulmonis, and mycoplasma neurolyticum), the pneumoniae group (which included species such as mycoplasma pneumoniae and mycopla ... | 1989 | 2592342 |
| a proposed life cycle model of spiroplasma mirum based on scanning electron microscopical observations of growth in liquid culture. | cells of spiroplasma mirum strain smca were grown in ppg broth and examined by scanning electron microscopy. comparison of the results at different time intervals allowed for a model of the life cycle of s. mirum to be proposed. under favorable growth conditions, helical filament formation was initially observed, followed by the formation of small spherical structures originating from each filament. in old culture, large spherical bodies appeared from entangled helical filaments. from the larger ... | 1989 | 2615674 |
| involvement of a spiroplasma citri plasmid in the erythromycin-resistance transfer. | an erythromycin-resistant strain (m4 er-1) was selected from spiroplasma citri m4+. the transfer by transformation of the erythromycin-resistance character to the erythromycin-sensitive s. citri strain r8a2+ was studied. transfer became effective and reproducible when cells were treated with alkali cations plus polyethylene glycol. comparison of the efficiency of transformation of the erythromycin-sensitive strain s. citri r8a2+ by total and extrachromosomal dna purified from the erythromycin-re ... | 1989 | 2623082 |
| mollicutes dna polymerases: characterization of a single enzyme from mycoplasma mycoides and ureaplasma urealyticum and of three enzymes from acholeplasma laidlawii. | the dna polymerase activity of different members of mollicutes was studied. a single dna polymerase was found in mycoplasma mycoides and ureaplasma urealyticum, type species of the genera mycoplasma and ureaplasma, and was compared with the previously described mycoplasma orale enzyme. most of their properties were comparable; an immunological relationship was demonstrated between m. orale and m. mycoides enzymes by immunoblotting. in contrast to these results, three different dna polymerases we ... | 1989 | 2694245 |
| synthesis and characterization of 6-o-(n-heptylcarbamoyl)-methyl-alpha-d-glucopyranoside, a new surfactant for membrane studies. | a new surfactant, 6-o-(n-heptylcarbamoyl)-methyl-alpha-d-glucopyranoside (hecameg, molar mass 335.38 g), was synthesized by a simple and low cost procedure from methyl-alpha-d-glucopyranoside. this surfactant is characterized by a high solubility in water (even at 0 degree c), ultraviolet light transparency in the region useful for protein detection, and a high critical micellar concentration (cmc = 19.5 mm), permitting fast elimination by dialysis. furthermore, the surfactant is colorimetricall ... | 1989 | 2757188 |
| topology and acylation of spiralin. | of the 51 polypeptides detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the plasma membrane of the helical mollicute spiroplasma melliferum, 21 are acylated, predominantly with myristic (14:0) and palmitic (16:0) chains. this is notably the case for spiralin, the major membrane protein of this bacterium, which contains an average of 0.7 acyl chains per polypeptide, attached very probably by ester bonds to alcohol amino acids. the amphiphilicity of spiralin was demonstrate ... | 1989 | 2768198 |
| effect of trimethoprim/sulphamethoxazole and hyperbaric oxygen on experimental spiroplasma mirum encephalitis. | this study was undertaken to determine the susceptibility of experimentally induced spiroplasma mirum infection in the rat to trimethoprim/sulfamethoxazole (tmp/smx) in combination with hyperbaric oxygen (hbo). one-day-old fisher 344 rats were intracerebrally inoculated with the gt-48 strain of s. mirum and were exposed to regimens employed combined antibiotic and hbo treatments. the exclusive use of tmp/smx produced a significant reduction in mortality (p less than 0.0001) and an absence of cli ... | 1989 | 2799063 |
| the nature of spiroplasma-like inclusions in experimental scrapie. | | 1987 | 2821451 |
| spiroplasma virus 4: nucleotide sequence of the viral dna, regulatory signals, and proposed genome organization. | the replicative form (rf) of spiroplasma virus 4 (spv4) has been cloned in escherichia coli, and the cloned rf has been shown to be infectious by transfection (m. c. pascarel-devilder, j. renaudin, and j.-m. bové, virology 151:390-393, 1986). the cloned spv4 rf was randomly subcloned and was fully sequenced by the dideoxy chain termination technique, using the m13 cloning and sequencing system. the nucleotide sequence of the spv4 genome contains 4,421 nucleotides with a g+c content of 32 mol%. t ... | 1987 | 2822658 |
| spiroplasma species share common dna sequences among their viruses, plasmids and genomes. | alkaline-southern-blot analyses showed that a spiroplasma plasmid, pra1, obtained from spiroplasma citri (maroc-r8a2), contained dna sequences that were homologous to spiroplasma type 3 viruses (sv3) obtained from s. citri (maroc-r8a2), s. citri (608) and s. mirum (smca). in addition, pra1 and sv3(608) dna shared common, but not necessarily related, sequences with extrachromosomal dna derived from 11 spiroplasma species or strains. furthermore, sv3(608) had dna homology with the chromosome from ... | 1987 | 2830894 |
| [spiroplasmas and hematophagous arthropods; prospects in tropical pathology]. | spiroplasmas are original wall-free prokaryotes which exhibit motility and a helical shape although lacking any cell wall or motile apparatus. they are known by phytopathologists because some of them are responsible for severe arthropod-borne plant diseases, such as spiroplasma citri, the etiologic agent of "citrus stubborn disease". other spiroplasmas are pathogenic for a number of insects: drosophila, bees and beetles. more recently spiroplasmas were also isolated from ticks, mosquitoes, horse ... | 1985 | 2873901 |
| [sensitivity to various antibiotics of spiroplasmas isolated from mosquitoes in france]. | spiroplasmas are helical mycoplasmas that play a significant role in plant diseases. they are also found in arthropods that are likely to bite humans, such as ticks and mosquitoes. these arthropods can act as vectors and therefore may be of epidemiologic significance. furthermore, mainly on the grounds of morphologic evidence, spiroplasmas have been incriminated in the genesis of human creutzfeld-jacob disease. we recovered six strains of spiroplasma sp. from 1927 female mosquitoes. in vitro sus ... | 1986 | 2877430 |
| immunochemical evidence for an active (f1-f0)-atpase in mycoplasmas. | in all acholeplasma, mycoplasma and spiroplasma species tested, a protein capable of reacting with antibodies prepared against the beta subunit of the proton-atpase complex from yeast, chloroplasts and escherichia coli was detected. the reactive protein of m. gallisepticum was found to be catalytically active, suggesting that mycoplasmas, as other bacteria, possess a proton-translocating atpase. characterization of the atpase activity of m. gallisepticum indicates that this organism also possess ... | 1987 | 2889695 |
| mosquito spiroplasmas from france and their ecology. | spiroplasmas have been isolated previously from a number of blood-sucking arthropods, including ticks, horseflies, and deerflies. more recently, spiroplasmas were isolated from mosquitoes from the usa, france, and taiwan. spiroplasmas isolated from mosquitoes from france belong to at least three serogroups and are serologically different from one of the taiwan isolates, sp2. our ar 1343 strain is the prototype of a new serogroup (xiii). during 3 consecutive years (1983-85), the ecology of these ... | 1987 | 2889698 |
| new spiroplasmas from insects and flowers: isolation, ecology, and host association. | eight spiroplasma strains from insects and one from spring flowers failed to react with antisera specific for any of the 11 described spiroplasma groups, with sera directed against spiroplasma group i subgroups, or with sera directed against two unnumbered groups previously reported to occur in tabanid flies. strains, all from maryland, were isolated from the hemolymph of the spotted cucumber beetle diabrotica undecimpunctata and the lampyrid beetle ellychnia corrusca, and the guts of the cantha ... | 1987 | 2889699 |
| transmembrane proton-motive potential of spiroplasma floricola. | in spiroplasma floricola, the transmembrane proton-motive potential delta p was studied. it is composed of a transmembrane electric potential difference, delta psi, and a transmembrane proton gradient, delta ph, according to delta p = delta psi - (z.delta ph). using a potential-sensitive carbocyanine dye and 5,5'-dimethyl[2-14c]oxazolidine-2,4-dione as probes, delta psi and delta ph were measured at different [h+] of the medium, and delta p was calculated to be remarkably constant at -123 mv +/- ... | 1987 | 2890538 |
| antiserum to scrapie-associated fibril protein cross-reacts with spiroplasma mirum fibril proteins. | protease-resistant fibril proteins purified from spiroplasma mirum and from creutzfeldt-jakob disease-infected brain tissues reacted with antisera to scrapie-associated fibrils on western immunoblot analysis. these data suggest that there are conformational similarities among spiroplasma proteins and infection-specific proteins of the transmissible spongiform encephalopathies. | 1987 | 2892856 |
| creutzfeldt-jakob disease, spiroplasmas, and crystalline artifacts. | | 1988 | 2903412 |
| the isolation of spiroplasmas from mosquitoes in macon county, alabama. | during the summer months of 1985, 1,298 adult mosquitoes comprising 21 species and 7 genera were collected in macon county, alabama. mosquitoes were collected from four sections of the county with co2-baited light traps. spiroplasma cultures were isolated from two pools of 24 and 25 aedes fulvus pallens, one pool of 22 anopheles punctipennis and one pool of 7 culex nigripalpus. electron microscopic studies of the isolates revealed helical, wall-less cells. | 1987 | 2904950 |
| lethal and mutation frequency responses of spiroplasma citri cells to uv irradiation. | the effect of uv irradiation on viability and mutant colony frequency in the mollicute spiroplasma citri was investigated at 3 phases of growth. the first uv-induced mutants obtained in mollicutes were selected: xylitol-resistant (xylr) and arsenic acid-resistant mutants (arsr). lethal and mutation frequency responses of s. citri cells increase with the age of the cell cultures. in all uv-irradiated populations, light exposure slightly increases the number of survivors and decreases the induced ... | 1989 | 2909865 |
| spiroplasma membrane lipids. | membranes of six spiroplasma strains belonging to different spiroplasma species and subgroups were isolated by a combination of osmotic lysis and sonication in the presence of edta to block endogenous phospholipase activity. analysis of membrane lipids showed that in addition to free and esterified cholesterol the spiroplasmas incorporated exogenous phospholipids from the growth medium. sphingomyelin was preferentially incorporated from phosphatidylcholine-sphingomyelin vesicles or from the seru ... | 1985 | 2981796 |
| gene for spiralin, the major membrane protein of the helical mollicute spiroplasma citri: cloning and expression in escherichia coli. | a library of cloned spiroplasma citri genomic sequences was constructed by incorporating hindiii digestion fragments into the plasmid vector pbr328. immunological screening allowed the identification of a recombinant plasmid containing the gene for spiralin, the major membrane protein of s. citri. the spiralin produced by the escherichia coli transformant was characterized by immunological detection with monoclonal antibody after western blotting of two-dimensional (isoelectric focusing and sodi ... | 1985 | 2999069 |