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the nasal mycoplasmal flora of healthy calves and cows.the nasal mycoplasmal flora of 270 healthy cows from 27 herds in the netherlands and 35 healthy calves from 7 of these herds was examined. various methods for isolating mycoplasmas were compared. the prevalence of the various species was as follows: ureaplasma diversum in 3 (9%) calves; mycoplasma dispar in 14 (40%) calves; m. bovis in 1 (3%) calf; m. bovirhinis in 23 (66%) calves and 16 (6%) cows; m. bovoculi in 8 (23%) calves and 53 (20%) cows; m. canis in 1 (3%) calf; m. equirhinis in 2 (1%) ...19921462726
effect of glycolipids on the phase behavior and dynamic properties of phospholipid liposomes.the glycolipids of acholeplasma laidlawii aih089 membranes were identified and purified. the effect of monoglucosyldiacylglycerol (mgdg) and diglucosyldiacylglycerol (dgdg) on the thermotropic behavior of multilamellar vesicles of dipalmitoylphosphatidylcholine (dppc), dipalmitoylphosphatidylglycerol (dppg) has been investigated by high sensitivity differential scanning calorimetry. the main transition peaks were broadened, the enthalpies were decreased. dgdg caused the decrease in the transitio ...19921510663
the enzymatic synthesis of membrane glucolipids in acholeplasma laidlawii.in membranes of the prokaryote acholeplasma laidlawii, the physiological regulation of the two major membrane lipids, monoglucosyldiacylglycerol (mglcdag) and diglucosyldiacylglycerol (dglcdag), is governed by factors affecting the equilibria between lamellar and non-lamellar phases of the membrane lipids. the synthesis of the glucolipids is considered to be a two-step glucosylation: (i) dag+udp-glc----mglcdag+udp; and (ii) mglcdag+udp-glc----dglcdag+upd. this was corroborated by in vivo pulse l ...19921533160
the effect of cholesterol and epicholesterol on the activity and temperature dependence of the purified, phospholipid-reconstituted (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes.the (na+ + mg2+)-atpase purified from acholeplasma laidlawii b membranes was reconstituted into large, unilamellar vesicles formed from dimyristoylphosphatidylcholine (dmpc) and varying amounts of cholesterol or epicholesterol. the atp hydrolytic activity of the reconstituted enzyme was then determined over a range of temperatures and the phase state of the dmpc in the atpase-containing vesicles was characterized by high-sensitivity differential scanning calorimetry. in the vesicles containing o ...19921535512
evolutionary relationships of a plant-pathogenic mycoplasmalike organism and acholeplasma laidlawii deduced from two ribosomal protein gene sequences.the families within the class mollicutes are distinguished by their morphologies, nutritional requirements, and abilities to metabolize certain compounds. biosystematic classification of the plant-pathogenic mycoplasmalike organisms (mlos) has been difficult because these organisms have not been cultured in vitro, and hence their nutritional requirements have not been determined nor have physiological characterizations been possible. to investigate the evolutionary relationship of the mlos to ot ...19921556079
[the chromatographic properties of the dna-dependent dna polymerases from acholeplasma laidlawii pg-8].the dna-dependent dna-polymerase (dna polymerase i which is not sorbed on the column with deae-cellulose, and dna-polymerase ii, which is absorbed by this column and is eluted from it by 0.3 m of nacl), have been isolated from acholeplasma laidlawii pg-8. dna-polymerase i in homogeneous state was obtained as a result of the stepwise treatment by heparin-sepharose (elution at 0.35 m of nacl) and poly-u-sepharose (elution at 0.3 m of nacl). it was presented on the electrophoregram by one polypepti ...19921584084
[rnase substrate specificity in acholeplasma laidlawii pg-8].a substrate specificity of rnases of a. laidlawii pg-8 to polynucleotides - poly (c), poly (u), poly (a) has been studied. due to the data obtained both intracellular and extracellular rnases of a. laidlawii possess similar specificity to different polynucleotides. both rnases preferentially break cytidine-bonds. specificity of the studied enzymes in respect to polyuridylic and polyadenylic acids was less expressed.19921584085
some observations on mycoplasma-cidal activity of horse serum. 19921606266
behaviour of a glycosphingolipid with unsaturated fatty acid in phosphatidylcholine bilayers.n-(oleoyl)galactosylceramide with perdeuterated acyl chain was prepared by partial synthesis, and studied by wide line 2h-nmr in phospholipid liposomes. spectra were obtained for low glycolipid concentrations in bilayers of dimyristoyl-, distearoyl-, and 1-palmitoyl-2-oleoylphosphatidylcholines. in an attempt to isolate the effects of glycosphingolipid fatty acid cis unsaturation on glycolipid behaviour in membranes, spectral findings related to the above species were compared to literature nmr ...19921616922
isoprenoid modification of proteins distinct from membrane acyl proteins in the prokaryote acholeplasma laidlawii.isoprenylation is an important posttranslational modification that affects the activity, subunit interactions and membrane anchoring of different eukaryotic proteins. the small, cell-wall-less prokaryote acholeplasma laidlawii has more than 20 membrane acyl-proteins enriched in myristoyl and palmitoyl chains. radioactive mevalonate, a precursor to isoprenoids, was incorporated into several specific membrane proteins of 20 to 45 kda and two soluble proteins of 23-25 kda, respectively. no acyl pro ...19921616923
[the inhibitory action of 6-azacytidine on mollicutes and its proposed mechanism].6-azacytidine (6-ac) is shown to have an inhibitory effect on the mollicutes of the different systematic position. the growth of type strains of mollicutes (acholeplasma laidlawii pg-8, mycoplasma pneumoniae fh and m. fermentans pg-18) completely ceased in the nutrient medium at concentration of the above substance in it within the range of 125-250 micrograms/ml. 50% inhibiting concentration of 6-ac equaled: for m. fermentans pg-8: 23.43 micrograms/ml; m. pneumoniae fn: 46.8 micrograms/ml; achol ...19937684488
[oligodeoxyribonucleotides complementary to sections of the mollicute ribosomal operon as transcription inhibitors in vitro].antisense oligodeoxyribonucleotides have been studied for their effect on the transcription in vitro in mollicutes. a synthetic fragment of dna [symbol: see text] complementary to that part of dna which codes the 1510-1521 area of the 3'-terminal sequence 16s-prna of all mollicutes was used in the study as well as its modifications by imidasophenasine derivatives: [symbol: see text], [symbol: see text] [symbol: see text]. maximal inhibition of the mollicute transcription in vitro was observed wi ...19937517768
[a cell-free translation system based on mollicute ribosomes].active cell-free protein-synthesizing systems are created on the basis of ribosomes of acholeplasma laidlawii var. granulum str. 118, a. laidlawii pg-8 and active lysates of eucaryotic cells (lysate of rabbit reticulocytes and wheat germ extract) in which activity of 80s-ribosomes was suppressed by addition of actidione in concentrations of 150 and 200 mkg/ml, respectively. it is shown that preincubation of active lysates of eucaryotic cells with actidione does not influence their ribosome inhib ...19938025692
systematic development and validation of sanitization protocols for a chromatographic system designed for biotherapeutics purification.production of protein therapeutics through the application of genetic engineering and biotechnology techniques requires comprehensive attention to good manufacturing practice and good laboratory practice (gmp/glp) guidelines for product recovery and purification. validated clean-in-place procedures are part of the master method and require analysis of microbial bioburden to assess the efficacy of cleaning protocols. this article describes the extensive microbial challenge of a chromatography sys ...19938123748
[soluble and semisoluble lectins from mollicutes and their possible functions].when studying mollicute lectins it was established that acholeplasma laidlawii pg-8 synthesizes two half-soluble lectins one of which is specific to n-acetyl-d-glucosamine, and the other--to d-glucosamine.hcl; phytopathogenic strain a. laidlawii var. granulum 118 produced 4 lectins one of which is soluble and specific in respect to fructose-1.6-diphosphate, the rest three lectins are half-soluble and specific to one of the sugars--d-galactosamine.hcl, rafinose and d-glucosamine.hcl. in mycoplasm ...19938220826
[the effect of mycoplasma contamination and decontamination with ciprofloxacin on the karyotypic structure of the chinese hamster v-79 lung cell line].karyotypic variability was investigated for the chinese hamster lung cell line v-79, infected (contaminated) with a mycoplasma acholeplasma laidlawii a. the mycoplasmal contamination did not affect cell distribution for the chromosome number. however, 30-70 days following cell culture contamination the increase in chromosomal aberrations was observed in the contaminated cell line primarily at the expense of chromosomal breaks. the following cyprofloxacin treatment of the culture resulted in myco ...19938266577
an enzyme-linked immunosorbent assay (elisa) for monitoring rodent colonies for streptobacillus moniliformis antibodies.an enzyme-linked immunosorbent assay (elisa) to measure streptobacillus moniliformis antibodies in mice and rats was developed. twelve s. moniliformis strains originating from cases of rat-bite fever and haverhill fever in man and from various rodent species, showed considerable serological relationship. the elisa appeared specific since antibodies to s. moniliformis were absorbed by autologous and homologous antigen, but not by heterologous bacterial antigens. acholeplasma laidlawii showed part ...19938277708
membrane lipid regulation in acholeplasma laidlawii grown with saturated fatty acids. biosynthesis of a triacylglucolipid forming reversed micelles.the membrane lipid composition in several strains of acholeplasma laidlawii is regulated upon a change in the growth conditions. monoglucosyldiacylglycerol (mglcdag) and diglucosyldiacylglycerol (dglcdag) are the most abundant lipids in the a. laidlawii membrane. a third glucolipid, 3-o-acyl-monoglucosyldiacylglycerol (mamglcdag) is synthesized by strain a-ef22 when the membrane lipids contain large amounts of saturated acyl chains. the lipid regulation can be understood from a simple theoretica ...19938344904
phylogenetic diversity of phytopathogenic mycoplasmalike organisms.by using specific primers, the 16s rrna genes of japanese mycoplasmalike organisms (mlos) were amplified by polymerase chain reactions from mlo-enriched fractions of plants infected with each of six different mlos. each of the polymerase chain reaction fragments (length, 1,370 nucleotides) was directly sequenced in both strands by using 17 oligonucleotide primers. a phylogenetic tree constructed by using the sequence data showed that these japanese mlos are phylogenetically diverse microorganism ...19938347505
[inhibitors of nucleic acid synthesis as a means of identifying the forms of dna-dependent dna polymerases in acholeplasma laidlawii pg-8 and of determining their functions].antibiotics, inhibitors of nucleic acids' synthesis from the group of chromomycins (olivomycin of sodium salt), anthracyclines (carminomycin and doxorubicin) and streptonigrin (bruneomycin) have been studied for their effect on dna synthesis in vitro performed by dna polymerases (1st and 2nd forms) of acholeplasma laidlawii pg-8. it has been stated that olivomycin inhibits the function of both the first and second forms of dna polymerases in proportion to an increase of the antibiotic concentrat ...19938355626
regulation and physicochemical properties of the polar lipids in acholeplasma laidlawii. 19938378987
presence of protein constituents of the gram-positive bacterial phosphotransferase regulatory system in acholeplasma laidlawii.acholeplasma species have been reported to lack a functional phosphoenolpyruvate:sugar phosphotransferase system (pts). we show here that acholeplasma laidlawii possesses activities of enzyme i, hpr, hpr(ser) kinase, and hpr(ser-p) phosphatase but lacks detectable activities of enzymes ii of the pts. hpr from this organism was purified, and the regulatory properties of the kinase and phosphatase were characterized and shown to differ from those of previously studied bacteria. the results suggest ...19938407837
cyclodextrins as carriers of cholesterol and fatty acids in cultivation of mycoplasmas.the design of fully or partly defined media for mycoplasma cultivation involves the need to provide the essential lipids, cholesterol and long-chain fatty acids, in an assimilable and nontoxic form. this study introduces cyclodextrins (cds) as carriers of these lipids, thus suggesting alternatives to serum or bovine serum albumin (bsa). the effects of beta-cd and two forms of chemically modified beta-cd, dimethyl-beta-cd (dimeb) and hydroxypropyl-beta-cd (hyprob), on the growth of mycoplasma cap ...19938434920
evidence for two pools of cholesterol in the acholeplasma laidlawii strain b membrane: a deuterium nmr and dsc study.recent investigations have indicated that there exists a well-defined range of membrane hydrocarbon order compatible with good growth of the microorganism acholeplasma laidlawii b [monck, m., bloom, m., lafleur, m., lewis, r. n. a. h., mcelhaney, r. n., & cullis, p. r. (1992) biochemistry 31, 10037-10043]. since cholesterol increases hydrocarbon order in membranes, it was of interest to examine the effect of cholesterol on the hydrocarbon order and growth characteristics of a. laidlawii b. chole ...19938457569
angiotensin ii binding sites on micro-organisms contaminating cell cultures.an angiotensin ii (ang ii) binding site, distinct from at1 and at2, has been found in cell cultures of rat aortic smooth muscle and rat glomerular mesangium. it is characterized by a high affinity for ang ii (kd 0.75 +/- 0.13 nm) and ang i (ki 0.72 +/- 0.12 nm), but a very low affinity for ang iii (ki 31 +/- 5 microm). ang(1-7) (ki 1.01 +/- 0.26 nm) and ang(1-6) (ki 4.54 +/- 0.24 nm) are very selective for this site, with affinities more than 150- and 10,000-fold greater, respectively, than for ...19938469777
phase transitions of acholeplasma laidlawii membranes. the involvement of mg(2+)-atpase in the c transition.highly sensitive differential scanning calorimetry has been employed to study the phase transitions of a. laidlawii membrane. the dsc curves obtained show five distinct transitions between 20 and 80 degrees c which contain a reversible lipid thermotropic transition at about 37 degrees c and four irreversible denaturation transitions of the membrane proteins occurred at about 44 degrees c, 52 degrees c, 62 degrees c, and 67 degrees c, respectively. total enthalpy of the thermal denaturation of me ...19938486158
[the kinetic and functional characteristics of dna-dependent dna-polymerases in acholeplasma laidlawii pg-8].the kinetic and functional characteristics of i and ii forms of dna-dependent dna-polymerases of acholeplasma laidlawii pg-8 have been studied. it is stated that i form of dna polymerase possesses 5'-3'-exonuclease activity and is a typical replicase; ii form of dna-polymerase possesses both 5'-3'-polymerase and 3'-5'-exonuclease activity and is, evidently, a reparase. both forms of enzyme give preference to poly(u)- and poly(a)-matrices having extremely high activity on these polymers. the enzy ...19938497202
quantitative ir studies of acyl chain conformational order in fatty acid homogeneous membranes of live cells of acholeplasma laidlawii b.acholeplasma laidlawii b has been grown highly enriched in myristic, pentadecanoic, and palmitic acids. the conformational order in the acyl chains of living cell membranes has been compared with that in the membranes of lysed cells and the lipids extracted therefrom, using fourier-transform infrared (ft-ir) spectroscopic techniques. a gel-liquid-crystal-phase transition (25-45 degrees c) was noted for both the live cells and the membranes. surprisingly, ch2 wagging progressions, characteristic ...19938512939
adaptation to altered growth temperatures in acholeplasma laidlawii b: fourier transform infrared studies of acyl chain conformational order in live cells.acholeplasma laidlawii b cells, highly enriched in saturated c14 and c15 fatty acids, have been grown at several temperatures. conformational order in the acyl chains of live cell membranes has been monitored with fourier-transform infrared (ft-ir) spectroscopy. coupled ch2 wagging progressions, characteristic of the all-trans conformation, have been used to quantitatively monitor the extent of trans-gauche isomerization. a simple model relating the changes in the progression intensity to the in ...19948142410
packing of a triacylglucolipid from the membrane of acholeplasma laidlawii strain a at the air/water interface.pressure-area curves were generated at 22 degrees c and 40 degrees c for three glucolipids isolated from acholeplasma laidlawii strain a-ef22. the glucolipids are 1,2-diacyl-3-o-(alpha-d-glucopyranosyl)-sn-glycerol (mglcdag), 1,2-diacyl-3-o-[alpha-d-glucopyranosyl-(1-->2)-o-alpha-d- glucopyranosyl]-sn-glycerol (dglcdag), and 1,2-diacyl-3-o-[3-o-acyl-(alpha-d-glucopyranosyl)]-sn- glycerol (mamglc-dag). the curves for mglcdag and dglcdag are characteristic for monolayers in a liquid phase at both ...19948142444
rapid, sensitive pcr-based detection of mycoplasmas in simulated samples of animal sera.a fast and simple method to detect mycoplasmal contamination in simulated samples of animal sera by using a pcr was developed. the following five mycoplasma species that are major cell culture contaminants belonging to the class mollicutes were investigated: mycoplasma arginini, acholeplasma laidlawii, mycoplasma hyorhinis, mycoplasma orale, and mycoplasma fermentans. after a concentration step involving seeded sera, genus-specific primers were used to amplify a 717-bp dna fragment within the 16 ...19948161186
novel polar lipid composition of clostridium innocuum as the basis for an assessment of its taxonomic status.the extractable polar lipids of clostridium innocuum have been shown to consist of glycosyldiradylglycerols, phospholipids and phosphoglycolipids. the major glycosyldiradylglycerols are d-glcp(alpha 1-3)radyl2gro and d-galp(alpha 1-2)d-glcp(alpha 1-3)radyl2gro. both glycolipids have some 1-o-(alk-1-enyl)-2-o-acyl species, in addition to diacyl species. the phospholipids include bisphosphatidylglycerol (cardiolipin), lysocardiolipin and phosphatidylglycerol (pg). in addition, several novel lipids ...19948162181
sequence analysis of a unique temperature phage: mycoplasma virus l2.mycoplasma virus l2 is a quasi-spherical enveloped virion containing circular double-stranded dna. l2 infection of acholeplasma laidlawii host cells leads to a noncytocidal productive infection cycle followed by establishment of lysogeny in all (or most) infected cells, with viral dna integrated into the host cell genome. the l2 genome has been sequenced and analyzed. l2 dna is 11,965-bp long and contains 15 open reading frames (orfs). one of these, orf13*, has its start codon within and in the ...19948163159
similar regulatory mechanisms despite differences in membrane lipid composition in acholeplasma laidlawii strains a-ef22 and b-pg9. a multivariate data analysis.mycoplasmas are small, cell wall-deficient bacteria. the metabolic regulation of the lipid composition in the membrane of the species acholeplasma laidlawii, strains a-ef22 and b-ju, is governed mainly by the balance between the potential formation of lamellar and nonlamellar phase structures. however, the regulatory features have not been consistently observed in the b-pg9 strain. a comparison has been performed between the membrane lipid composition for strains a-ef22 and b-pg9, simultaneously ...19948172919
[cloning universal probes for detecting mycoplasma contamination of cell cultures].to obtain the universal polynucleotide hybridization probes for testing mycoplasmal contaminations in cell cultures, we have cloned several dna fragments from the srrna gene of acholeplasma laidlawii. before cloning, in order to exclude cross-hybridization of these probes with eukaryotic rrna, the thermodynamic parameters of duplex formation between dna complementary to mycoplasmal rrna and eukaryotic rrna had been studied. using a set of computer methods, the region which forms weak heteroduple ...19948183277
regulation and phase equilibria of membrane lipids from bacillus megaterium and acholeplasma laidlawii strain a containing methyl-branched acyl chains.phosphatidylethanolamine (pe) was isolated from bacillus megaterium grown at 20 and 55 degrees c (pe-20 and pe-55). iso and anteiso methyl-branched, saturated acyl chains are predominant in b. megaterium, and the value of the molar ratio of iso/anteiso acyl chains is more than 20-fold higher in pe-55 than in pe-20. moreover, about 21 mol% of the acyl chains of pe-20 are monounsaturated. the phase equilibria differ between the two pe preparations: (1) pe-20 is more prone to form reversed nonlamel ...19948193124
activation of the membrane glucolipid synthesis in acholeplasma laidlawii by phosphatidylglycerol and other anionic lipids.in membrane lipids of the prokaryote acholeplasma laidlawii similar phase equilibria and a nearly constant spontaneous curvature are maintained by an extensive metabolic regulation of especially the major polar lipids monoglucosyldiacylglycerol (mglcdag) and diglucosyldiacylglycerol (dglcdag), forming nonlamellar and lamellar phases, respectively. a constant surface charge density is maintained by the anionic phospholipid fraction. these lipids are synthesized from phosphatidic acid in two compe ...19948089114
phylogenetic relationships among members of the class mollicutes deduced from rps3 gene sequences.a gene for a ribosomal protein, rps3, was amplified by pcr and sequenced from representatives of the class mollicutes. alignments of the deduced amino acid sequences allowed the construction of a phylogeny that is consistent with the phylogenetic trees created from 5s and 16s rrna comparisons, including the position of the former acholeplasma florum on the mycoplasma branch, rather than with the classical acholeplasmataceae. additional confirmation of the phylogeny comes from the deduction that ...19948123554
structures of glucolipids from the membrane of acholeplasma laidlawii strain a-ef22. i. glycerophosphoryldiglucosyldiacylglycerol and monoacylbisglycerophosphoryldiglucosyldiacylglycerol.the structures of two phosphoglucolipids from the membrane of acholeplasma laidlawii, strain a-ef22 were determined by high resolution 13c-, 31p- and 1h-nmr. the lipids in question are 1,2-diacyl-3-o-[glycerophosphoryl-6-o-(alpha-d-glucopyranosyl- (1-->2)-o-alpha-d-glucopyranosyl)]-sn-glycerol (1) and 1,2-diacyl-3-o-[glycerophosphoryl-6-o-(alpha-d-glucopyranosyl-(1-- >2)- monoacyl-glycerophosphoryl-6-o-alpha-d-glucopyranosyl)]-sn-glycero l (2). both lipids are thus derivatives of diglucosyldiacy ...19947918591
membrane thickness and molecular ordering in acholeplasma laidlawii strain a studied by 2h nmr spectroscopy.since acholeplasma laidlawii can be restricted to incorporating fatty acids from the growth medium into its membrane lipids, it is possible to study the effects of the length of the acyl chains on the properties of the membrane of the organism. a. laidlawii strain a-ef22 was grown with mixtures of one perdeuterated saturated fatty acid and one monounsaturated fatty acid. the average length (<cn>) of the acyl chains in the membrane lipids varied from 14.6 to 19.9, and the degree of unsaturation r ...19947947725
tubular structures of mycoplasma gallisepticum and their possible participation in cell motility.in five strains of mycoplasma gallisepticum, a protein with a molecular mass of about 40 kda was detected by immunoblotting with anti-pig brain tubulin polyclonal and monoclonal antibodies. in eight other mycoplasma species similarly tested no reaction was observed. thin serial sections of m. gallisepticum and acholeplasma laidlawii cells examined by transmission electron microscopy revealed a submembrane system of tubules in m. gallisepticum but not in a. laidlawii. the intracellular spatial di ...19948012588
phylogenetic classification of phytopathogenic mollicutes by sequence analysis of 16s ribosomal dna.the phylogenetic relationships of 17 phytopathogenic mycoplasmalike organisms (mlos) representing seven major taxonomic groups established on the basis of mlo 16s ribosomal dna (rdna) restriction patterns were examined by performing a sequence analysis of the 16s rdna gene. the sequence data showed that the mlos which we examined are members of a relatively homogeneous group that evolved monophyletically from a common ancestor. in agreement with results obtained previously with other mlos, our r ...19947520735
[the effect of mycoplasmal contamination of cultures of skin fibroblasts from the indian muntjac and of the subsequent decontamination of the cultures using ciprofloxacin on the karyotypic structure of the cell line].the karyotypic variability of indian muntjac skin fibroblast cell line, cultured for 95-168 days after contamination with acholeplasma laidlawii strain pg-8, has been investigated. the contaminated cultures differ from noncontaminated ones in cell distribution for chromosome number. the noncontaminated cultures have modal number of chromosomes equal to 7 with the main structure variant of the karyotype (svk) 2+2+1+1+1. in the contaminated cultures the cell number with 7 chromosomes and the main ...19947809977
structures of glucolipids from the membrane of acholeplasma laidlawii strain a-ef22. ii. monoacylmonoglucosyldiacylglycerol.the structure of one glucolipid from the membrane of acholeplasma laidlawii, strain a-ef22, was determined. this glucolipid is synthesized only when a large fraction of saturated, straight-chain fatty acids are incorporated into the membrane lipids of strain a-ef22. the lipid was studied by 1h- and 13c-nmr spectroscopy. the structure of the lipid is 1,2-diacyl-3-o-[6-o-acyl-(alpha-d-glucopyranosyl)]-sn-glycerol. the result for this lipid shows that a previously published structure, based on inco ...19947811721
thermotropic phase properties of 1,2-di-o-tetradecyl-3-o-(3-o-methyl- beta-d-glucopyranosyl)-sn-glycerol.the hydration properties and the phase structure of 1,2-di-o-tetradecyl-3-o(3-o-methyl-beta-d-glucopyranosyl)-sn-glycerol (3-o-me-beta-d-glcdaig) in water have been studied via differential scanning calorimetry, 1h-nmr and 2h-nmr spectroscopy, and x-ray diffraction. results indicate that this lipid forms a crystalline (lc) phase up to temperatures of 60-70 degrees c, where a transition through a metastable reversed hexagonal (hll) phase to a reversed micellar solution (l2) phase occurs. experime ...19947811919
mycoplasma stimulates hiv-1 expression from acutely- and dormantly-infected promonocyte/monoblastoid cell lines.treatment of a myelo-monocyte cell line, j22hl-60, dormantly infected with human immunodeficiency virus type 1 (hiv-1) with heat-inactivated extracts of acholeplasma (a) laidlawii (250 micrograms/ml) enhanced virus production more than 45-fold as assessed by p24 viral core antigen assay. when treated with a suboptimal dose of tpa or tnf-alpha, acholeplasma extracts further augmented virus production in j22hl-60 cells. h7, an inhibitor of protein kinase c(pkc), almost completely abrogated hiv-1-i ...19947832648
phylogenetic analysis of mycoplasma strain ism1499 and its assignment to the acholeplasma oculi strain cluster.a mycoplasma strain designated ism1499 was used to develop a mycoplasma genetic system (g. g. mahairas and f. c. minion, j. bacteriol. 171:1775-1780, 1989; g. g. mahairas, c. jian, and f. c. minion, gene 93:61-65, 1990), but phenotypic inconsistencies led to the conclusion that this organism had been classified incorrectly as a member of the species mycoplasma pulmonis. studies were initiated to determine the proper taxonomic position of ism1499, and on the basis of the results of our genetic an ...19957857790
membrane lipid composition and cell size of acholeplasma laidlawii strain a are strongly influenced by lipid acyl chain length.the small, cell-wall-less prokaryote acholeplasma laidlawii strain a-ef22 could grow with membrane lipids having an average acyl chain length cn varying over 14.5- almost 20 carbons by exogenous supplementation with selected fatty acids. for 16 < cn < 18, the cells grew with lipids containing 100% (mol/100 mol) monounsaturated acyl chains, whereas for cn < 16 and cn > 18, cell growth only occurred with gradually lower fractions of unsaturated chains. cn was actively increased and decreased by ch ...19957867633
taxonomic analysis of the tortoise mycoplasmas mycoplasma agassizii and mycoplasma testudinis by 16s rrna gene sequence comparison.the nucleotide sequences of the 16s rrna genes of two mycoplasmas, mycoplasma agassizii (proposed sp. nov.) and mycoplasma testudinis, isolated from tortoises were determined and used for taxonomic comparisons. signature nucleotide sequence motifs and overall sequence similarities to other mollicutes positioned these mycoplasmas in the m. hyorhinis and m. pneumoniae phylogenetic groups, respectively. a third, previously unrecognized tortoise mycoplasma was detected by 16s rrna gene amplification ...19957537069
efficient modulation of glucolipid enzyme activities in membranes of acholeplasma laidlawii by the type of lipids in the bilayer matrix.it is generally anticipated, but so far not fully shown, that the physical properties of membrane lipid bilayers are governed by the concerted actions of the lipid-synthesizing enzymes. in the membrane of acholeplasma laidlawii a constant surface charge density, similar phase equilibria, and a nearly constant spontaneous curvature are maintained for the polar lipids. important for these properties are monoglucosyldiacylglycerol (mglcdag) and diglucosyldiacylglycerol (dglcdag), forming mainly rev ...19957577924
quantitation of the phase preferences of the major lipids of the acholeplasma laidlawii b membrane.we have quantitated the phase preferences of all of the quantitatively significant lipids of fatty acid-homogeneous acholeplasma laidlawii membranes by determining the effect of small amounts of each lipid on the lamellar/reversed hexagonal phase transition temperature of a phosphatidylethanolamine matrix of identical fatty acid composition using differential scanning calorimetry. we find that the incorporation of small amounts of these lipids produce effects ranging from a moderate depression t ...19957577974
acholeplasma laidlawii b membranes contain a lipid (glycerylphosphoryldiglucosyldiacylglycerol) which forms micelles rather than lamellar or reversed phases when dispersed in water.it has been proposed that each of the lipids from the acholeplasma laidlawii membrane prefers to form either a lamellar or a reversed cubic or hexagonal phase when dispersed in excess water at physiologically relevant temperatures and ionic strengths. in this study, we have reinvestigated the thermotropic phase behavior of all the major membrane lipids from a. laidlawii b membranes derived from cells grown in equimolar palmitic and elaidic acids. we confirm that phosphatidylglycerol (pg) and dig ...19957577975
lipid extracts from membranes of acholeplasma laidlawii a grown with different fatty acids have a nearly constant spontaneous curvature.x-ray diffraction methods were used to explore the variation in the spontaneous curvature of lipid extracts from acholeplasma laidlawii strain a-ef22 grown with different mixtures of palmitic acid and oleic acid. it was shown that the cells respond to the different growing conditions by altering the polar head group compositions in order to keep the phase transition between lamellar and nonlamellar structures within a narrow temperature range. this has been interpreted to mean that the membrane ...19957599176
structures of glucolipids from the membrane of acholeplasma laidlawii strain a-ef22. iii. monoglucosyldiacylglycerol, diglucosyldiacylglycerol, and monoacyldiglucosyldiacylglycerol.the structures of three glucolipids from the membrane of acholeplasma laidlawii, strain a-ef22, were determined by high resolution 1h-nmr and 13c-nmr spectroscopy. the two most abundant glucolipids in this organism were shown to be 1,2-diacyl-3-o-(alpha-d-glucopyranosyl)-sn-glycerol (mglcdag) and 1,2-diacyl-3-o-[alpha-d-glucopyranosyl-(1 --> 2)-o-alpha-d- glucopyranosyl]-sn-glycerol (dglcdag). these structures agree with those determined previously by chemical analyses of the two most abundant g ...19957654774
[the phenotypic traits of mollicutes as their possible phylogenetic markers].interaction of cells of mollicutes acholeplasma laidlawii pg 8, a. laidlawii var. granulum 18, mycoplasma hominis pg 21, m. pneumoniae fh, m. fermentans pg 118 and their extracellular products with different carbohydrates, plant lectins of different carbohydrate specificity with glycocalix carbohydrates of the same microorganisms has been studied. basing on this study and data from literature a conclusion is made that such phenotypical characteristics as the ability to form extracellular fructos ...19957655655
[the ability of the oligodeoxyribonucleotides complementary to the 3'-terminal segment of 16s-rrna in mollicutes to suppress translation in their ribosomes in an in-vitro system].effect of oligodesoxyribonucleotide, complementary to 3'-end sequence (3'-ucuuuccuccac) of 16s-rrna of mollicutes, and its phenasine derivatives on the process of translation of mollicute has been studied in the system of in vitro translation, created on the basis of ribosomes of acholeplasma laidlawii var. granulum str. 118 and germ extracts of the wheat and optimized in respect of the temperature (23 degrees c), translation time (70 min), concentration of potassium and magnesium ions (150 and ...19957655656
possible monosaccharide composition of glycopolymers located on the external side of membranes of cells of some mollicutes.monosaccharide composition of glycopolymers of five mollicutes (mycoplasma pneumoniae fh, m. hominis pg 21, m. fermentans pg 18, acholeplasma laidlawii pg 8 and a. laidlawii var. granulum 118) integrated with their membrane has been studied by means of nine plant lectins with certain carbohydrate specificity labelled with colloid gold. monosaccharide composition of glycopolymers depends both on the mollicute species and on its capacity to evoke diseases in different microorganisms. thus genetica ...19957663744
influence of monoglucosyldiacylglycerol and monoacylmonoglucosyldiacylglycerol on the lipid bilayer of the membrane from acholeplasma laidlawii strain a-ef22.the ability for 1,2-diacyl-3-o-(alpha-d-glucopyranosyl)-sn-glycerol (mglcdag) and 1,2-diacyl-3-o-(6-o-acyl-(alpha-d-glucopyranosyl))-sn-glycerol (mamglcdag) to induce non-lamellar phases in a lipid mixture with an in vivo composition, prepared from acholeplasma laidlawii membranes, has been investigated. the phase transition temperatures from lamellar to non-lamellar structures were studied with varying fractions of mglcdag and mamglcdag. the transition temperature decreased from 73 +/- 2 degree ...19957488623
expression of foreign genes and selection of promoter sequences in acholeplasma laidlawii.the stable maintenance and expression of foreign genes in mollicutes (mycoplasmas) have been difficult to achieve due to the lack of suitable vectors. in this paper we show for the first time that a replicating vector can been used to express foreign genes other than antibiotic resistance genes in acholeplasma laidlawii. plasmids derived from the lactococcal vector pnz18 could introduce and maintain four different genes for many generations in a. laidlawii. one of these, encoding the dominant me ...19957496518
effects of pentachlorophenol and biotic interactions on soil fauna and decomposition in humus soil.in a laboratory experiment, effects of chemical stress (pentachlorophenol, pcp, at concentrations of 0, 50, and 500 mg/kg) and biotic interactions (nematodes in the presence or absence of collembolas and enchytraeids) on the community structure of soil animals and decomposition processes were studied. pcp was strongly adsorbed to humus that contained 65% organic matter. numbers of fungal-feeding nematodes decreased significantly at the highest pcp concentration, while no effects were found in ba ...19957498064
[clastogenic effect of mycoplasma on human chromosomes]. 19958535262
[a factor to enhance hiv replication in serum bearing a resemblance to membranes of acholeplasma laidlawii].we found a substance a in human serum by elisa method, using anti-a antibody. the substance a was obtained from the membranes of a. laidlawii and this enhanced hiv replication. this substance in human serum was detected in the chloroform phase of the bligh-dyer method. rf value in thin layer chromatography was 0.28. this substance clearly showed enhancement of hiv replication as well as the activity of the membranes of a. laidlawii, but did not induce tnf production. furthermore, the activity wh ...19958586892
fluctuations in ir spectral parameters detected in mixed acyl chain membranes of acholeplasma laidlawii b.acholeplasma laidlawii b cells were grown at 37 degrees c on three binary c16:0-d(31)/c18:1 fatty acid mixtures at initial mol ratios of 3:2, 1:1, and 2:3. these mol ratios produced final c16:0-d(31)/c18:1 lipid acyl chain mol ratios of 1.66 +/- 0.23 (n=6), 1.3 +/- 0.20 (n=6) and 0.58 +/- 0.09 (n=10), respectively, in the membrane of the microorganism. membrane conformational order for the deuterated and proteated acyl chains in intact cells was monitored by ft-ir spectroscopy through the thermo ...19968624360
characterization of the ftsz gene from mycoplasma pulmonis, an organism lacking a cell wall.the ftsz gene is required for cell division in escherichia coli and bacillus subtilis. in these organisms, ftsz is located in a ring at the leading edge of the septum. this ring is thought to be responsible for invagination of the septum, either causing invagination of the cytoplasmic membrane or activating septum-specific peptidoglycan biosynthesis. in this paper, we report that the cell division gene ftsz is present in two mycoplasma species, mycoplasma pulmonis and acholeplasma laidlawii, whi ...19968636032
chromatographic resolution of partially perdeuterated diglucosyldiacylglycerols from acholeplasma laidlawii.diglucosyldiacylglycerol from acholeplasma laidlawii was isolated by adsorption chromatography and subsequently subjected to molecular species analysis by reversed-phase high-performance liquid chromatography. twenty-three molecular species were resolved. the bacterium was grown in a medium supplemented with a mixture of oleic acid and perdeuterated palmitic acid, and incorporation of perdeuterated acyl moieties occurred in several molecular species. short and odd-numbered acyl chains were found ...19968673252
evaluation of current sterility tests for human live viral vaccines.current sterility tests for human viral vaccines were evaluated. a total of 43 lots of bulk suspension of live viral vaccines (measles, mumps, rubella and oral poliomyelitis) produced by six manufacturers in japan were evaluated for bacteriostatic and mycoplasmastatic activities. some of them showed fairly high bacteriostatic and mycoplasmastatic activities, due to antibiotics added during vaccine production. it was concluded that the current sterility test for mycoplasmas is not reliable to det ...19968733601
correlation between bilayer lipid dynamics and activity of the diglucosyldiacylglycerol synthase from acholeplasma laidlawii membranes.in the single membrane of acholeplasma laidlawii a specific glucosyltransferase synthesize the major, lamellar-forming lipid diglucosyldiacylglycerol (dglcdag) from the major, nonlamellar-prone monoglucosyldiacylglycerol (mglcdag). this is crucial for the maintenance of phase equilibria close to a bilayer-nonbilayer transition and a nearly constant spontaneous curvature in the membrane lipid bilayer. acyl chain order is also affected, but not kept constant. phosphatidylglycerol (pg) is an essent ...19968756472
[the effect of the mycoplasma contamination of 2 kidney cell sublines from the kangaroo rat on their karyotypic structure].the karyotypic variability has been investigated for two cell sublines of rat kangaroo kidney cultured for 40-160 days after contamination with acholeplasma laidlawii, strain pg-8. the contaminated cultures did not differ from non-contaminated ones in cell distribution for chromosome number. the majority of cells of subline nbl-3-11 with modal number of chromosomes displayed the main structural variant of the karyotype (svk)--2+2+2+2+2+1; in subline nbl-3-17 the main svk being 3+3+3+3+3+2. a com ...19968768552
[the detection of proteolytic enzymes in the culture broth of mollicutes].four strains of mollicutes different in their role in pathology of people, animals and plants have been studied to detect general proteolytic (caseinolytic) activity with results presented. proteolytic activity was determined both in the deposited proteins and in supersediment liquids under suturation with ammonium sulphate of 55 and 80%, respectively. maximum proteolytic activity was observed in supersediment liquids. it was 137.2 e per 1 mg of protein in m. fermentans pg-18; 106.2 in a. laidla ...19968777466
new aspects on membrane lipid regulation in acholeplasma laidlawii a and phase equilibria of monoacyldiglucosyldiacylglycerol.a new membrane lipid, monoacyldiglucosyldiacylglycerol (madglcdag), was recently discovered in acholeplasma laidlawii strain a-ef22, demanding a new study of the biosynthetic regulation, and the phase behavior, of the glucolipids in this organism. the only liquid-crystalline phase formed by madglcdag is a reversed hexagonal phase. a. laidlawii a-ef22 synthesizes four lipids that have the ability to induce the formation of reversed nonlamellar phases: madglcdag, monoglucosyldiacylglycerol (mglcda ...19968780516
sequence and organization of genes encoding enzymes involved in pyruvate metabolism in mycoplasma capricolum.the region of the genome of mycoplasma capricolum upstream of the portion encompassing the genes for enzymes i and iiaglc of the phosphoenolpyruvate:sugar phosphotransferase system (pts) was cloned and sequenced. examination of the sequence revealed open reading frames corresponding to numerous genes involved with the oxidation of pyruvate. the deduced gene organization is naox (encoding nadh oxidase)-lpla (encoding lipoate-protein ligase)-odpa (encoding pyruvate dehydrogenase ei alpha)-odpb (en ...19968844861
reduction of benzyl viologen distinguishes genera of the class mollicutes.we tested the ability of 62 growing strains belonging to the class mollicutes to reduce the redox indicator and free-radical generator 1,1'-dibenzyl-4,4'-bipyridinium dichloride (benzyl viologen [bv]) to a blue-violet-purple color. bv was reduced by 12 acholeplasma species but not by acholeplasma multiforme pn525t (t = type strain). bv was also reduced by five of nine mesoplasma species and by four of six entomoplasma species. bv was not reduced by 19 mycoplasma species, six spiroplasma species, ...19968863413
differential and strain-specific triggering of bovine alveolar macrophage effector functions by mycoplasmas.mycoplasma strains being considered as pathogenic or non-pathogenic for cattle were tested on their capacity to activate bovine alveolar macrophages in vitro. of particular interest was the behaviour of mycoplasma mycoides ssp. mycoides small colony type (m.m.m. sc), the causative agent of contagious bovine pleuropneumonia (cbpp). increases in procoagulant activity (pca), tumor necrosis factor-alpha- (tnf-alpha) and nitrogen monoxide (no) generation were tested. to minimize an influence of macro ...19968971688
differential scanning calorimetric study of the interaction of cholesterol with the major lipids of the acholeplasma laidlawii b membrane.it has been proposed that the lower levels of exogenous cholesterol incorporation into the membranes of the sterol-non-requiring as compared to the sterol-requiring mycoplasmas may be due to the much higher glycolipid content of the former and to the reduced ability of glycolipids, as opposed to phospholipids, to incorporate sterols [efrati et al. (1986) arch. biochem. biophys. 248, 282-288]. in order to test this hypothesis, we have investigated the interaction of cholesterol with the major mem ...19968988017
[the inhibition of translation in vivo in mollicutes by thiophosphate analogs of oligodeoxyribonucleotides].it is shown that the concentration of "antisignature" phosphorothioate analogs of oligodeoxynucleotides, complementary to the region of 165 rrna acholeplasma laidlawii pg-8 and mycoplasma fermentans pg-18 responsible tor binding with ribosomal protein s4 being 0.5--1 microm synthesis of proteins in vivo decreases to 70%. a model of mechanisms is suggested to block oligonucleotides of the process of in vivo translation in mollicutes by "antisignature" phosphorothioate analogs. the advantages of t ...19968991592
pathologic responses of lambs to experimental inoculation with acholeplasma laidlawii. 19969026067
nisin resistance distinguishes mycoplasma spp. from acholeplasma spp. and provides a basis for selective growth media.the sensitivity of 11 mycoplasma and 5 acholeplasma species to the bacteriocin nisin was determined. when applied on filter paper discs to lawns of acholeplasma cells, nisin (20 nmol per disc) gave 3.5- to 7.0-mm zones of growth inhibition. the inclusion of 0.2 mm nisin in agar medium reduced the number of acholeplasma laidlawii colonies by a factor of more than 10(6), and in a salts solution, 75 microm nisin killed more than 99.9% of cells within 1 min. under similar conditions, nisin had no si ...199611783455
[the sorption of antisense oligodeoxyribonucleotides by mycoplasma cells].the paper deals with kinetics of binding of antisense oligodesoxyribonucleotides, complementary to certain sequences 16 s rna of mollicutes, by the cells of three representatives of class mollicutes: acholeplasma laidlawii pg-8. mycoplasma pneumoniae fh and m. fermentans pg-18. it is shown that binding of antisense oligonucleotides by the mollicute cells depends on temperature and age of cultures. the highest level of sorption of labelled antisense oligodesoxyribonucleotides by the cells of myco ...19969044700
[the validation of the possible use of monosugars and 6-azacytidine for the elimination of mollicutes associated with hiv/aids from the human urogenital tract].a search for the methods new in principle which should block and eliminate aids-associated mycoplasmas was carried out. this work was conducted in two ways: 1) inhibition of vital activity of mycoplasma fermentans pg-18 and acholeplasma laidlawii pg-8 by 6-azacytidine; 2) establishment of carbohydrate composition of receptors for these mycoplasmas aimed at the competitive elimination of these microorganisms from urogenital tract of a man using carbohydrates. it is established that a 50%-inhibiti ...19969044715
[the binding and absorption by mollicute cells of antisignature analogs of oligodeoxyribonucleotides].processes of absorption and uptake of phosphorothioate, phosphorodithioate and methylphosphonate analogs of oligodeoxynucleotides which are complementary to "signature" 16s rrna sequences by cells of acholeplasma laidlawii pg-8. mycoplasma fermentans pg-18 and mycoplasma pneumoniae fh have been investigated. distinctions in efficiency of absorption by given cells of phosphorothioate and methylphosphonate analogs of oligonucleotides are found out. so, the level of thioates sorption by the cells o ...19969064069
production of a t-cell clone which reacts with membrane proteins of acholeplasma laidlawii.the role of cellular immunity in mycoplasma infection is not completely understood. in this study, we established mycoplasma-specific t-cell clones to evaluate cellular immunity in mycoplasma infection. we developed a t-cell clone (g-10) which was stimulated with acholeplasma laidlawii. the t-cell clone g-10, cd4+ and t-cell receptor (tcr) alpha beta- recognized the 42- and 65-kilodalton (kda) membrane proteins of a. laidlawii and responded to a. hippikon. hence, the application of mycoplasma-sp ...19979130238
phosphocholine-containing glycoglycerolipids (ggpl-i and ggpl-iii) are species-specific major immunodeterminants of mycoplasma fermentans.mycoplasma fermentans has unique glycoglycerophospholipids (ggpls: ggpl-i and ggpl-iii). previously, the structure of these lipids was determined as phosphocholine-6'-alpha-glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (ggpl-i) and 1"-phosphocholine-2"-aminodihydroxypropane-3"-phospho-6'-alph++ + a- glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (ggpl-iii). thin-layer chromatography (tlc) immunostaining showed that the ggpls were main lipid-antigens of the m. fermentans species. anti-m. fermentans seru ...19979168906
[the modification of the internucleotide relations of antisignature oligodeoxyribonucleotides as a means of increasing their resistance to nuclease cleavage in mollicute cells].modifications in 5'- and 3'-ends and internucleotide bondings of antisignature oligodesoxyribonucleotides have been studied for their resistance to nuclease cleavage in cells of acholeplasma laidlawii pg-8 and mycoplasma fermentans pg-18. it is shown that adding of benzylamide grouping to the 5'-end of oligonucleotides increases their half-life period in the studied mollicute cells to 15 h. s-methyl modification of 3'-end of antisignature oligonucleotides did not take essential effect on the pro ...19979172862
antisignature oligonucleotides and their analogs as inhibitors of mollicutes-cofactors of hiv.inhibition of mollicutes by synthetic oligonucleotides and their analogs complementary to specific "signature" regions of 16s rrna and corresponding sequences of ribosomal operon dna was studied. it was shown that antisignature oligonucleotides inhibited transcription in vitro for above 79% interacting specifically with ribosomal operon and non-specific with dna-dependent rna-polymerase. the inhibition efficiency depended on oligonucleotide sequence and type of modification. translation in vitro ...19979177600
nonlamellar phases induced by the interaction of gramicidin s with lipid bilayers. a possible relationship to membrane-disrupting activity.the interactions of the cyclic peptide gramicidin s (gs) with a variety of single-component lipid bilayers, and with membrane polar lipid extracts of acholeplasma laidlawii b and escherichia coli, were examined by differential scanning calorimetry (dsc), 31p-nuclear magnetic resonance (nmr) spectroscopy, and x-ray diffraction. the dsc data indicate that the effects of gs on the thermotropic phase behavior of phosphatidylcholine and phosphatidylethanolamine dispersions are compatible with those e ...19979201936
[the binding activity of diglucosyl diacylglyceride derived from membranes of acholeplasma laidlawii pg8 to lymphoid cells].a chemical component has been purified from acholeplasma laidlawii which binds to tissue culture cells, molt-4, hut-78, but not mt-4 and jurkat. the glycolipid in the membranes of a. laidlawii was extracted by bligh-dyer method. further purification of chloroform phase of bligh-dyer method was performed by silicagel column chromatography and thin layer chromatography. finally, the active component was assigned to be diglucosyl diacylglyceride by using nuclear magnetic resonance (1h, 13c). furthe ...19979248270
antibody response to mfgl-ii, a phosphocholine-containing major lipid of mycoplasma fermentans membranes.the choline-containing phosphoglycolipid, mfgl-ii, is the major polar lipid of mycoplasma fermentans pg18. anti-mfgl-ii antisera raised in rabbits using the purified mfgl-ii as an immunogen were employed in immunogold electron microscopic and immunofluorescence studies showing that mfgl-ii is uniformly distributed and exposed on the cell surface of m. fermentans cells. the specificity of the antibodies was determined by immunostaining of lipid extracts separated by thin layer chromatography. the ...19979311135
epidemiologic analysis of mycoplasma spp isolated from bulk-tank milk samples obtained from dairy herds that were members of a milk cooperative.to determine the prevalence of mycoplasma spp in herds that were members of a milk cooperative.19979343550
activating amphiphiles cause a conformational change of the 1,2-diacylglycerol 3-glucosyltransferase from acholeplasma laidlawii membranes according to proteolytic digestion.1,2-diacylglycerol 3-glucosyltransferase synthesizes the major nonbilayer-prone lipid monoglucosyldiacylglycerol (mglcdag) in the membrane of acholeplasma laidlawii, which is important for the spontaneous curvature, and is a regulatory site for the lipid surface charge density. a potential connection between activity and a conformational change of this enzyme, governed by essential lipid activators, was studied with purified mglcdag synthase in different lipid aggregates. critical fractions of a ...19979368025
effects on mollicutes (wall-less bacteria) of synthetic peptides comprising a signal peptide or a membrane fusion peptide, and a nuclear localization sequence (nls) -- a comparison with melittin.in order to investigate the effect of primary amphipathic peptides on mollicutes (wall-less bacteria), we have synthesised five molecules (p1, p2, p3, jm123, and jm133) comprising a 16 to 18-residue hydrophobic sequence and the nuclear localization sequence (nls) pkkkrkv of simian virus 40 large-t antigen, c-terminated by a cysteamide group. the hydrophobic cluster was in p1 the signal sequence of the heavy chain of caiman crocodilus immunoglobulin g and in jm123 the fusion peptide of human immu ...19979371427
purification of a phosphatase which hydrolyzes phosphatidic acid, a key intermediate in glucolipid synthesis in acholeplasma laidlawii a membranes.a phosphatidic acid phosphatase (pap; ec 3.1.3.4.), dephosphorylating phosphatidic acid (pa) to diacylglycerol (dag), was identified and purified from the plasma membrane of acholeplasma laidlawii a. after four purification steps, including membrane preparation, tween 20 solubilization, preparative gel electrophoresis and electro-elution, pap was purified about 400 times to near homogeneity. the molecular weight of pap was according to sds-polyacrylamide gel electrophoresis approximately 25 kda ...19979408176
cryo-tem and nmr studies of a micelle-forming phosphoglucolipid from membranes of acholeplasma laidlawii a and b.the chemical structure of a phosphoglucolipid from the membrane of the bacterium acholeplasma laidlawii strain b-pg9 has been determined by high resolution nmr to be 1,2-diacyl-3-o-[glycerophosphoryl-6-o-(alpha-d-glucopyranosyl-(1 -->2)-o-alpha-d-glucopyranosyl)]-sn-glycerol (gpdglcdag). it was concluded that this lipid has exactly the same structure as one of the phosphoglucolipids from a. laidlawii strain a-ef22. by cryo transmission electron microscopy (cryo-tem) and nmr diffusion techniques ...19979032946
lipid dependence and basic kinetics of the purified 1,2-diacylglycerol 3-glucosyltransferase from membranes of acholeplasma laidlawii.udp-glucose: 1,2-diacylglycerol 3-glucosyltransferase (ec 2.4.1.157), catalyzes the transfer of glucose from udp-glucose to diacylglycerol (dag) to yield monoglucosyldiacylglycerol (mglcdag) and udp. mglcdag is the first glucolipid along the glucolipid pathway, and a major (nonbilayer-prone) lipid in the single membrane of acholeplasma laidlawii. mglcdag is further glucosylated to give the major diglucosyldiacylglycerol (dglc-dag). the bilayer fractions of these lipids are crucial for the metabo ...19978995384
occurrence of monoacyl-diglucosyl-diacyl-glycerol and monoacyl-bis-glycerophosphoryl-diglucosyl-diacyl-glycerol in membranes of acholeplasma laidlawii strain b-pg9.it is shown by thin-layer and high-performance liquid chromatography that the two membrane lipids monoacyl-diglucosyl-diacyl-glycerol (madglcdag) and monoacyl-bis-glycerophosphoryl-diglucosyl-diacyl-glycerol are synthesized by acholeplasma laidlawii strain b-pg9 when the cells are grown in two different growth media. the two lipids are also synthesized by a. laidlawii strain a-ef22 and their chemical structures have been determined previously by nmr spectroscopy. since a reversed hexagonal phase ...19989443602
synthesis, antimicrobial activity and gene structure of a novel member of the dermaseptin b family.dermaseptins are a family of cationic (lys-rich) antimicrobial peptides that are abundant in the skin secretions of the arboreal frogs phyllomedusa bicolor and p. sauvagii. in vitro, these peptides are microbicidal against a wide variety of microorganisms including gram-positive and gram-negative bacteria, yeasts, protozoa and fungi. to date, 6 dermaseptin b mature peptides, 24-34 residues long, 2 dermaseptin b cdnas and 2 gene sequences have been identified in p. bicolor. to assess dermaseptin ...19989540838
[effect of mycoplasma contamination of the human uterine leiomyosarcoma cell line sk-ut-1b on karyotype structure].the karyotypic variability has been investigated for human uterine leiomyosarcoma cell line sk-ut-1b, cultivated for 30-90 days after contamination with acholeplasma laidlawii, strain pg-8. the character of cell distribution for chromosome number gradually changes in contaminated cells, comparatively to the control, with the lengthening of the term of contamination. so, in 30 days the analysed distributions do not differ in the experimental and in the control variants, the modal number of chromo ...19989541971
lipids in total extracts from acholeplasma laidlawii a pack more closely than the individual lipids. monolayers studied at the air-water interface.pressure-area curves were obtained at 25, 35 and 45 degrees c for total lipid extracts and four individual glucolipids isolated from acholeplasma laidlawii strain a-ef22. the glucolipids are 1,2-diacyl-3-0-(alpha-d-glucopyranosyl)-sn-glycerol (mglcdag), 1,2 -diacyl-3-0-[alpha-d-glucopyranosyl-(1-->2)-0-alpha-d-glucopyranosyl] -sn-glycerol (dglcdag), 1,2-diacyl-3-0-[alpha-d-glucopyranosyl-(1-->2)-0-(6-0-acyl-alpha-d-gluco pyranosyl)]-sn-glycerol (madglcdag), and 1,2-diacyl-3-0-[glycerophosphoryl- ...19989556349
membrane permeabilisation and antimycoplasmic activity of the 18-residue peptaibols, trichorzins pa.the membrane permeabilisation properties of six linear natural 18-residue peptaibols, termed trichorzins pa, have been assessed on liposomes and on mollicutes (trivial name, mycoplasmas), a class of parasitic bacteria characterized by a small genome, the lack of a cell wall, a minute cell size, and the incorporation in their plasma membrane of exogenously supplied cholesterol. the trichorzins pa used in this study (pa ii, pa iv-vi, pa viii, and pa ix) differ between them by amino acid or amino a ...19989651487
expression of foreign genes in acholeplasma laidlawii. 19989711661
[formation of m. hominis and a. laidlawii resistance to fluoroquinolones].mycoplasma hominis and acholeplasma laidlawii cultures resistant to antibacterial fluoroquinolone drugs ciprofloxacin (cpf), ofloxacin (ofl), and lomefloxacin (lmf) were prepared by selection in liquid nutrient medium with ascending concentrations of cpf. resistant mycoplasma clones contained point mutations in the gyrase. a gene region determining quinolone resistance (qrdr gyra): m. hominis contained c-->t transition resulting in substitution of ser(83) for leu and a. laidlawii g-->a resulting ...19989819821
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