Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 ... | 1995 | 7577974 |
| 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 ... | 1995 | 7577975 |
| 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 ... | 1995 | 7599176 |
| 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 ... | 1995 | 7654774 |
| [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 ... | 1995 | 7655655 |
| [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 ... | 1995 | 7655656 |
| 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 ... | 1995 | 7663744 |
| [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 ... | 1993 | 7684488 |
| [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 ... | 1994 | 7809977 |
| 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 ... | 1994 | 7811721 |
| 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 ... | 1994 | 7811919 |
| 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 ... | 1994 | 7832648 |
| 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 ... | 1995 | 7857790 |
| 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 ... | 1995 | 7867633 |
| 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 ... | 1994 | 7918591 |
| 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 ... | 1994 | 7947725 |
| 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 ... | 1994 | 8012588 |
| [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 ... | 1993 | 8025692 |
| 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 ... | 1994 | 8089114 |
| 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 ... | 1994 | 8123554 |
| 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 ... | 1993 | 8123748 |
| 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 ... | 1994 | 8142410 |
| 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 ... | 1994 | 8142444 |
| 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 ... | 1994 | 8161186 |
| 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 ... | 1994 | 8162181 |
| 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 ... | 1994 | 8163159 |
| 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 ... | 1994 | 8172919 |
| [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 ... | 1994 | 8183277 |
| 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 ... | 1994 | 8193124 |
| [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 ... | 1993 | 8220826 |
| [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 ... | 1993 | 8266577 |
| 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 ... | 1993 | 8277708 |
| 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 ... | 1993 | 8344904 |
| 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 ... | 1993 | 8347505 |
| [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 ... | 1993 | 8355626 |
| regulation and physicochemical properties of the polar lipids in acholeplasma laidlawii. | 1993 | 8378987 | |
| 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 ... | 1993 | 8407837 |
| 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 ... | 1993 | 8434920 |
| 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 ... | 1993 | 8457569 |
| 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 ... | 1993 | 8469777 |
| 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 ... | 1993 | 8486158 |
| [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 ... | 1993 | 8497202 |
| 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 ... | 1993 | 8512939 |
| [clastogenic effect of mycoplasma on human chromosomes]. | 1995 | 8535262 | |
| [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 ... | 1995 | 8586892 |
| 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 ... | 1996 | 8624360 |
| 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 ... | 1996 | 8636032 |
| 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 ... | 1996 | 8673252 |
| 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 ... | 1996 | 8733601 |
| 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 ... | 1996 | 8756472 |
| [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 ... | 1996 | 8768552 |
| [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 ... | 1996 | 8777466 |
| 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 ... | 1996 | 8780516 |
| 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 ... | 1996 | 8844861 |
| 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, ... | 1996 | 8863413 |
| 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 ... | 1996 | 8971688 |
| 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 ... | 1996 | 8988017 |
| [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 ... | 1996 | 8991592 |
| 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 ... | 1997 | 8995384 |
| pathologic responses of lambs to experimental inoculation with acholeplasma laidlawii. | 1996 | 9026067 | |
| 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 ... | 1997 | 9032946 |
| [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 ... | 1996 | 9044700 |
| [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 ... | 1996 | 9044715 |
| [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 ... | 1996 | 9064069 |
| 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 ... | 1997 | 9130238 |
| 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 ... | 1997 | 9168906 |
| [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 ... | 1997 | 9172862 |
| 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 ... | 1997 | 9177600 |
| 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 ... | 1997 | 9201936 |
| [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 ... | 1997 | 9248270 |
| 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 ... | 1997 | 9311135 |
| 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. | 1997 | 9343550 |
| 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 ... | 1997 | 9368025 |
| 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 ... | 1997 | 9371427 |
| 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 ... | 1997 | 9408176 |
| 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 ... | 1998 | 9443602 |
| 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 ... | 1998 | 9540838 |
| [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 ... | 1998 | 9541971 |
| 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- ... | 1998 | 9556349 |
| 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 ... | 1998 | 9651487 |
| expression of foreign genes in acholeplasma laidlawii. | 1998 | 9711661 | |
| [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 ... | 1998 | 9819821 |
| total lipids with short and long acyl chains from acholeplasma form nonlamellar phases. | the cell-wall-less bacterium acholeplasma laidlawii a-ef22 synthesizes eight glycerolipids. some of them form lamellar phases, whereas others are able to form normal or reversed nonlamellar phases. in this study we examined the phase properties of total lipid extracts with limiting average acyl chain lengths of 15 and 19 carbon atoms. the temperature at which these extracts formed reversed hexagonal (hii) phases differed by 5-10 degreesc when the water contents were 20-30 wt%. thus the cells adj ... | 1998 | 9826609 |
| zelkovamycin, a new cyclic peptide antibiotic from streptomyces sp. k96-0670. i. production, isolation and biological properties. | a new antibiotic termed zelkovamycin was isolated from the fermentation broth of streptomyces sp. k96-0670 by solvent extraction, ods column chromatography and preparative hplc. zelkovamycin showed antibacterial activity against xanthomonas oryzae, acholeplasma laidlawii, pyricularia oryzae and staphylococcus aureus. | 1999 | 10092194 |
| [changes in the properties of the plasma membrane of acholeplasma laidlawii under the action of tetracycline]. | the role of physico-chemical rearrangements in the cell plasmalemma of acholeplasma laidlawii in the development of resistance to tetracycline was investigated. the cells of a.laidlawii were shown to be tolerant to tetracycline and to preserve a rather high titre of the cells even at a concentration of the antibiotic in the inoculation medium much higher than the mic. the results of the investigation of the structural rearrangements in the plasmatic membrane of the cells grown in the presence of ... | 1999 | 10202551 |
| key role of the diglucosyldiacylglycerol synthase for the nonbilayer-bilayer lipid balance of acholeplasma laidlawii membranes. | in the single membrane of acholeplasma laidlawii, a specific glucosyltransferase (dglcdag synthase) synthesizes the major, bilayer-forming lipid diglucosyldiacylglycerol (dglcdag) from the preceding major, nonbilayer-prone monoglucosyldiacylglycerol (mglcdag). this is crucial for the maintenance of phase equilibria close to a potential bilayer-nonbilayer transition and a nearly constant spontaneous curvature for the membrane bilayer lipid mixture. the glucolipid pathway is also balanced against ... | 1999 | 10220338 |
| [cloning and expression of the gene for the mycoplasma key division protein ftsz in escherichia coli]. | gene ftsz responsible for division of bacterial cells was revealed in most prokaryote groups. a 520-bp fragment of the ftsz gene was amplified on the template of a. laidlawii dna using degenerate primers. this fragment was sequenced and served as a hybridization probe for cloning of the full-sized copy of the a. laidlawii ftsz gene. the amplified fragment was cloned in a pgex3x vector and expressed in e. coli cells. polyclonal antibodies derived from the chimeric polypeptide containing a fragmen ... | 1999 | 10368784 |
| molecular analysis of the cytolytic protein clya (shea) from escherichia coli. | escherichia coli k-12 carries a gene for a protein denoted clya or shea that can mediate a cytolytic phenotype. the clya protein is not expressed at detectable levels in most strains of e. coli, but overproduction suitable for purification was accomplished by cloning the structural gene in an hns mutant strain. highly purified clya protein was cytotoxic to macrophage cells in culture and caused detachment and lysis of the mammalian cells. results from osmotic protection assays were consistent wi ... | 1999 | 10383763 |
| characterization of acholeplasma laidlawii ftsz gene and its gene product. | the ftsz gene was found among representatives of all bacterial groups. ftsz protein is an essential component of cell division ring. contraction of this cytoskeleton-like ring is believed to be the universal way of bacterial division. acholeplasma laidlawii possesses all features of the minimal mycoplasma cell and some traits of cell-wall bacteria and seems to be a promising object for study of basic principles of the bacterial division process. we cloned an a. laidlawii chromosomal fragment con ... | 1999 | 10448065 |
| bactericidal/permeability-increasing protein inhibits growth of a strain of acholeplasma laidlawii and l forms of the gram-positive bacteria staphylococcus aureus and streptococcus pyogenes. | bactericidal/permeability-increasing protein (bpi) inhibited growth of cell wall-deficient acholeplasma laidlawii and l forms of certain strains of staphylococcus aureus and streptococcus pyogenes. however, the same strains of s. aureus and s. pyogenes with intact cell walls were not susceptible to the growth-inhibitory effects of bpi. | 1999 | 10471588 |
| a polymerase chain reaction based method for detecting mycoplasma/acholeplasma contaminants in cell culture. | a detection system that utilizes a primer mixture in a nested polymerase chain reaction for detecting mycoplasma contaminants in cell cultures is described. primers were designed to amplify the spacer regions between the 16s and 23s ribosomal rna genes of mycoplasma and acholeplasma. this detection system was able to detect 20-180 colony forming units per milliliter of sample. eight commonly encountered mycoplasma and acholeplasma contaminants, which include mycoplasma (m.) arginini, m. fermenta ... | 2000 | 10576701 |
| [the study of quantitative karyotypic variability by induction of chromosomal instability in cultured cells of the indian muntjac skin fibroblasts]. | the influence of mycoplasmal contamination and somatic cell hybridization on the character of karyotypic variability in cell cultures of indian muntjac skin fibroblasts has been investigated. mycoplasma arginini and acholeplasma laidlawii, used as factors inducing chromosomal instability, do not break the main regulations peculiar to intact control. they regulations are: 1) nonrandom character of cell distribution according to the number of chromosomal deviations from msvk; 2) specific character ... | 1999 | 10591121 |
| [the monosaccharide composition of the glycocalyx in mollicutes and phylogenetically related bacteria in the genus bacillus]. | a number of monosaccharides composing the glycocalix carbohydrates of some mollicutes (mycoplasma pneumoniae fh, m. hominis pg21, m. fermentans pg18, acholeplasma laidlawii pg8, a. laidlawii var. granulum st. 118) and phylogenetically related bacteria from the genus bacillus (bacillus cereus 89, b. cereus dm423, b. subtilis 1/2, b. licheniformis 31, b. licheniformis 49) were detected using plant lectins of definite carbohydrate specificity labelled by colloid gold. the structure of extracellular ... | 1999 | 10643272 |
| the nonbilayer/bilayer lipid balance in membranes. regulatory enzyme in acholeplasma laidlawii is stimulated by metabolic phosphates, activator phospholipids, and double-stranded dna. | in membranes of acholeplasma laidlawii a single glucosyltransferase step between the major, nonbilayer-prone monoglucosyl-diacylglycerol (mglcdag) and the bilayer-forming diglucosyl-diacylglycerol (dglcdag) is important for maintenance of lipid phase equilibria and curvature packing stress. this dglcdag synthase is activated in a cooperative fashion by phosphatidylglycerol (pg), but in vivo pg amounts are not enough for efficient dglcdag synthesis. in vitro, phospholipids with an sn-glycero-3-ph ... | 2000 | 10734070 |
| [the effect of mycoplasmal contamination of human embryonic lung cell line mrc-5 on the karyotypic variability]. | karyotypic variability has been investigated for nonimmortalized human embryonic lung cell line mrc-5, cultivated with acholeplasma laidlawii strain pg-8 for 15-45 days. the character of cell distribution for chromosome number did not change during this time. in all investigated variants the number of polyploid cells increased considerably with the lengthening of the term after decryoconservation. the number of chromosomal aberrations in 15-45 days contaminated cells increased significantly as c ... | 2000 | 10752125 |
| application of membrane filtration for removal of diminutive bioburden organisms in pharmaceutical products and processes. | in this report, we present results of a recent investigation in our laboratories demonstrated the effect of process conditions and/or drug product composition on the ability of 0.2 micron and 0.22 micron sterilizing grade filters to fully retain ralstonia (formerly burkholderia, formerly pseudomonas) pickettii. r. pickettii is a opportunistic pathogen widely distributed in nature as well as clinical specimens and there have been several reports of nosocomial infections due to intrinsic manufactu ... | 1999 | 10754712 |
| common elements of spiroplasma plectroviruses revealed by nucleotide sequence of svts2. | dna of spv1-like spiroplasma plectroviruses (rods with single-stranded circular dna) is scattered in the genome of the phytopathogen spiroplasma citri and has significant consequences for evolution of the s. citri genome. we determined the complete nucleotide sequence of svts2, a spv1-like virus of s. melliferum, a honeybee pathogen, to ascertain, by comparison with s. citri spv1 viruses (genbank u28974 and x51344), the defining features of this important group. the 6,824 nt dna contains nine or ... | 2000 | 10766306 |
| effect of some psychotropic drugs and a barbiturate on mycoplasmas. | the inhibitory effect of selected membrane stabilisers on mycoplasma pneumoniae, m. hominis and ureaplasma urealyticum was investigated in vitro. the phenothiazine chlorpromazine (cpz) and the barbiturate thiopental (leopental(r)) as well as the stereo-isomeric thioxanthene derivatives; cis(z)-clopenthixol (zu-clopenthixol(r))/ trans (e)-clopenthixol and cis (z)-chlorprothixen (truxal(r))/trans(e)-chlorprothixen, all have antimycoplasmal effect in the range 3.9-312 mg/l, measured as growth inhib ... | 2000 | 10773494 |
| [analysis of genes, coding for dna gyrase from the mycoplasma acholeplasma laidlawii pg-8b]. | 2000 | 10779957 | |
| development and qualification of a novel virus removal filter for cell culture applications. | commercial bioreactors employing mammalian cell cultures to express biological or pharmaceutical products can become contaminated with adventitious viruses. the high expense of such a contamination can be reduced by passing all gases and fluids feeding the bioreactor through virus inactivation or removal steps, which act as viral barriers around the bioreactor. a novel virus barrier filter has been developed for removing viruses from serum-free cell culture media. this filter removes the 20 nm m ... | 2000 | 10835245 |