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identification of an enveloped phage, mycoplasma virus l172, that contains a 14-kilobase single-stranded dna genome.we have found that mycoplasma virus l172 is an enveloped globular virion containing circular, single-stranded dna of 14.0 kilobases. l172 has been reported by other workers to have a double-stranded dna genome of 13 to 17 kilobase pairs and has been classified as a plasmavirus, a group for which mycoplasma virus l2 is the type member. mycoplasma viruses l172 and l2 differ in genome size and structure, dna base composition, and protein composition, and they have no detectable dna homology. as the ...19852982026
effect of positively charged local anesthetics on a membrane-bound phosphatase in acholeplasma laidlawii.the plasma membrane p-nitrophenylphosphatase activity of acholeplasma laidlawii was stimulated by the spin-labeled local anesthetic 2-[n-methyl-n-(2,2,6,6-tetramethylpiperidinooxyl)]ethyl p-hexyloxybenzoate, abbreviated as c6sl, and its methylated quaternary analog, c6slmei. the tertiary amine c6sl (at a concentration of 5 x 10(-5) m) was more potent at ph 6.5 than at ph 7.7. in contrast, the permanently-charged c6slmei was equally potent, independently of ph. these results suggest that cationic ...19852988562
reconstitution and photolabeling of the purified (na+ + mg2+)-atpase from the plasma membrane of acholeplasma laidlawii b with phospholipids containing a photosensitive fatty acyl group.the purified membrane (na+ + mg2+)-atpase of acholeplasma laidlawii b was reconstituted into vesicles composed of phospholipids containing a photoactivatable aryl nitrene-generating fatty acyl group. the reconstitution with phospholipid resulted in an enhancement of atpase activity and a reduction in the sensitivity of the enzyme to radiation inactivation. the incorporation of the enzyme into the lipid vesicles results in a broadening of the gel-to-liquid-crystalline phase transition of the phot ...19852933074
transfection of rep- mycoplasmas with viral single-stranded dna.double-stranded dna from mycoplasma virus l2 can transfect acholeplasma laidlawii cells in the presence of polyethylene glycol (t. l. sladek and j. maniloff, j. bacteriol. 155:734-741, 1983). we report here that both single-stranded dna and double-stranded replicative form dna, from the single-stranded dna mycoplasma virus l51, are also infectious in this system. for both dnas transfection frequencies were in the range of 10(-8) transfectants per dna molecule and 10(-3) transfectants per cfu. an ...19853965744
pyrimidine deoxyribonucleotide metabolism in acholeplasma laidlawii b-pg9.extracts of acholeplasma laidlawii b-pg9 were examined for the enzymes associated with the interconversion of the pyrimidine deoxyribonucleotides and the biosynthesis of thymidine nucleotides. a. laidlawii b-pg9 possessed deaminases for deoxycytidine and dcmp, pyrophosphatases for dutp, phosphorylases for thymidine and uridine, and a membrane-associated pyrimidine deoxyribonucleoside monophosphate phosphatase activity. the role these enzyme activities have in the generation of deoxyribose-1-phos ...19853972768
identification of lipoglycan antigens from the acholeplasma laidlawii cell membrane in crossed immunoelectrophoresis.membranes from the wall-less prokaryote acholeplasma laidlawii contain a component termed lipoglycan or lipopolysaccharide (lps). the lipoglycan has extraction properties, which are similar to those of lps of gram-negative bacteria, but it is chemically distinct from bacterial lps. the membrane-bound lipoglycan of a. laidlawii did not seem to be particularly immunogenic and antibodies against it could not always be detected by rocket immunoelectrophoresis (rie) or crossed immunoelectrophoresis ( ...19853979563
acylated proteins in acholeplasma laidlawii.the covalent modification of membrane proteins by long-chain fatty acids was determined in two strains of acholeplasma laidlawii by one-dimensional gel electrophoresis of radiolabeled membranes. of the more than 50 membrane polypeptides detected, approximately 30 were labeled with [3h]palmitate, whereas covalent binding of [3h]oleate to membrane proteins could not be demonstrated. we suggest that in these wall-less bacteria, membrane protein acylation with saturated fatty acids may serve to ensu ...19853980443
involvement of surface potential in regulation of polar membrane lipids in acholeplasma laidlawii.upon induced variation of membrane lipid acyl chain unsaturation in acholeplasma laidlawii, the cells strongly change in a characteristic manner the proportions of individual (charged and noncharged) polar lipids synthesized. monolayer analysis of polar lipid extracts revealed different mean lateral molecular areas but similar surface charge densities. microelectrophoresis of these lipids indicated an almost constant lipid membrane zeta-potential of about -35 mv. simulation by the gouy-chapman-s ...19853980463
19f nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. orientational order in the presence of a series of positional isomers of cis-octadecenoic acid.the 19f nuclear magnetic resonance (nmr) spectra of membranes of acholeplasma laidlawii b enriched with one of a series of positional isomers of cis-octadecenoic acid plus small amounts of one of a number of isomers of monofluoropalmitic acid were interpreted in terms of an orientational order parameter (smol). the variation of smol with the position of the fluorine label in the liquid-crystalline state yielded an "order profile" with characteristics similar to those obtained via 2h nmr and whic ...19853994965
[acholeplasma laidlawii cell culture as an object for studying age-related changes in biological membranes]. 19853996198
heterogeneous progeny viruses are produced by a budding enveloped phage.infection of acholeplasma laidlawii cells by the temperate enveloped mycoplasma virus l2 results in production of three morphological forms of progeny l2 virus: l2-i, l2-ii, and l2-iii. these morphological forms can be separated by velocity sedimentation and agarose gel electrophoresis. the latter technique was used to size the quasi-spherical particles: l2-i is 74 nm, l2-ii is 88 nm, and l2-iii is 132 nm in diameter. the protein composition of the three l2 forms is the same, although there are ...19854008216
fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. gel-state disorder in the presence of methyl iso- and anteiso-branched-chain substituents.the hydrocarbon chain orientational order parameters of membranes of acholeplasma laidlawii b enriched with large quantities of a linear saturated, a methyl iso-branched, or a methyl anteiso-branched fatty acid plus small quantities of various isomeric monofluoropalmitic acid probes were determined via fluorine-19 nuclear magnetic resonance spectroscopy (19f nmr) over a range of temperatures spanning the gel to liquid-crystalline phase transitions (determined by differential scanning calorimetry ...19854016065
evidence for the bacterial origin of acholeplasma laidlawii a.l-forms from a corynebacterium were induced in hyperosmolar media and gradually adapted to normal osmolarity over a period of two years. during this adaptation several morphologic l-form variants derived from the l-form cultures and were serologically identified as acholeplasma laidlawii a. the possibility that the bacterial and l-form cultures were contaminated with acholeplasmas was carefully investigated; this was determined not to be the case. membrane protein gel electrophoresis patterns of ...19854028662
acholeplasma laidlawii cells acutely and chronically infected with group 1 acholeplasmavirus.interactions between group 1 acholeplasmaviruses and their host cells were studied. acutely infected, chronically infected and uninfected cultures of acholeplasma laidlawii strain ja1 were compared by their growth in broth and on agar, by the sensitivities of the uninfected and chronically infected cells to representatives of each of the three groups of acholeplasmaviruses, and by their sds-page polypeptide profiles. acutely infected cells resembled uninfected cells by these criteria, except for ...19854045426
infrared spectroscopic study of the gel to liquid-crystal phase transition in live acholeplasma laidlawii cells.the temperature dependences of the infrared spectra of deuterium-labeled plasma membranes of live acholeplasma laidlawii b cells and of the isolated plasma membranes demonstrate that the profiles of the gel to liquid-crystal phase transitions are very different. at temperatures within the range of the phase transition, the live mycoplasma is able to keep the "fluidity" of its plasma membrane at a much higher value than that of the isolated plasma membrane at the same temperature. the difference ...19854052402
prevalence of mycoplasma and acholeplasma species in cattle exhibiting various clinical diseases and pathological lesions in morocco. 19854060938
fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. a direct comparison of the effects of cis and trans cyclopropane ring and double-bond substituents on orientational order.the hydrocarbon chain orientational order parameters of membranes of acholeplasma laidlawii b, enriched with large quantities of fatty acids containing either a cis or a trans cyclopropane ring or a cis or trans double bond, plus small quantities of one of an isomeric series of monofluoropalmitic acids, were determined via fluorine-19 nuclear magnetic resonance spectroscopy over a range of temperatures spanning the corresponding gel to liquid-crystalline phase transitions (determined via differe ...19854063347
the photosensitizing activity of haematoporphyrin on mollicutes.the photosensitizing activity of haematoporphyrin (hp) on mycoplasma hominis and acholeplasma laidlawii was studied as a function of the phase of growth and the amount of sterols in the cell membrane. less hp was bound to cells when the membrane had a high sterol content. both strains in the exponential but not in the stationary phase of growth were sensitive to hp treatment (above 1 microgram ml-1) in the dark. visible light irradiation of hp-loaded cells caused in all cases a decrease of cell ...19854067577
selection and propagation of antibiotic-resistant mutants of acholeplasma by the addition of fresh culture medium containing antibiotics and protease to the medium cultured with acholeplasma. 19854087872
the effect of mycoplasmas and acholeplasmas of equine origin on organ cultures of chicken-embryo trachea.chicken-embryo tracheal organ cultures were inoculated with equine strains of mycoplasma arginini, m. equigenitalium, 2 strains of m. subdolum, acholeplasma laidlawii and 3 strains of a. oculi. all strains established and multiplied in the explant cultures, but only m. subdolum and a. oculi produced a cytopathic effect on ciliated epithelial cells, causing sloughing of cells and cilia after 6 days. there was a correlation between ciliostasis and increase in titre of both m. subdolum and a. oculi ...19853837791
polymeric phospholipids as new biomaterials.phospholipid polymers form a new class of biomaterials with many potential applications in medicine and research. the development of these compounds is based upon the mimicry of cell surfaces and reflects our current understanding of the properties of membrane lipids. physicochemical characterization of the monomeric, diacetylenic phospholipids illustrates the similarities to naturally occurring lipids, similarities that are confirmed by the capacity to enrich the membranes of a. laidlawii to th ...19853860157
fracturing of melamine-embedded cells and tissues: a new technique for studying cell membranes.a new technique is presented for studying cell membranes by scanning electron microscopy. it is based on the observation that cells and tissues, embedded in a water-compatible melamine resin, are as hard as glass and consequently can be fractured with ease. fracture faces so exposed are either sputter-coated for studying the surface topography or re-embedded for thin-sectioning, or both. scanning electron microscopy shows that the fracture faces of a variety of tissues reveal cell membranes and ...19853871862
elimination of mycoplasmas from cell cultures utilizing hyperimmune sera.eighteen cell lines contaminated with various mycoplasmas have been treated with hyperimmune sera and mycoplasmas have been eradicated from all. after treatment the cell lines have been observed for a least one year and they are still free from mycoplasma contamination as ascertained by four independent mycoplasma detection assays. the hyperimmune sera used were of high titer, type-specific and growth-inhibiting. these sera were produced by immunization of rabbits with purified membranes from my ...19853902490
acholeplasma laidlawii retains sensitivity to exogenous virus while releasing endogenous, mitomycin c induced, virus. brief report.three of five acholeplasma laidlawii strains were found to carry mitomycin c inducible acholeplasmaviruses. these virus hosts were capable of propagating (1) virus homologous to the one it carried, and (2) exogenous virus while releasing induced endogenous virus.19853925928
construction of the mycoplasma evolutionary tree from 5s rrna sequence data.the 5s rrna sequences of eubacteria and mycoplasmas have been analyzed and a phylogenetic tree constructed. we determined the sequences of 5s rrna from clostridium innocuum, acholeplasma laidlawii, acholeplasma modicum, anaeroplasma bactoclasticum, anaeroplasma abactoclasticum, ureaplasma urealyticum, mycoplasma mycoides mycoides, mycoplasma pneumoniae, and mycoplasma gallisepticum. analysis of these and published sequences shows that mycoplasmas form a coherent phylogenetic group that, with c. ...19852579388
purification and characterization of a dutpase from acholeplasma laidlawii b-pg9.dutp was purified 120-fold from extracts of acholeplasma laidlawii b-pg9 by blue-sepharose, phenyl-sepharose, hydroxyapatite, and deae-sephacel chromatography techniques. the only substrate for the enzyme was dutp with an apparent km of 4.5 microm. the only reaction products were dump and ppi. the dutpase did not exhibit any specific divalent cation requirement, but it was inhibited by edta. the enzyme was not inhibited by pi or p-hydroxymercuribenzoate. the molecular weight of the enzyme was es ...19846145699
properties of the membrane-bound mg2+-atpase isolated from acholeplasma laidlawii. 19846148965
yet another improved silver staining method for the detection of proteins in polyacrylamide gels.silver staining is very sensitive for detection of proteins in polyacrylamide gels and different procedures have been published. by combining and modifying some of the recipes, a very reproducible method, which is based upon staining with diamine complexes of silver, has been developed. the background staining is negligible and reduced silver does not precipitate on the gel surface. the technique works very well for sodium dodecyl sulfate-polyacrylamide gel electrophoresis in both homogeneous an ...19846203956
the structure and function of the acholeplasma laidlawii plasma membrane. 19846318828
purine metabolism in acholeplasma laidlawii b: novel ppi-dependent nucleoside kinase activity.acholeplasma laidlawii b-pg9 was examined for 16 cytoplasmic enzymes with activity for purine salvage and interconversion. phosphoribosyltransferase activities for adenine, guanine, xanthine, and hypoxanthine were shown. adenine, guanine, xanthine, and hypoxanthine were ribosylated to their nucleoside. adenosine, inosine, xanthosine, and guanosine were converted to their base. no atp-dependent phosphorylation of nucleosides to mononucleotides was found. however, ppi-dependent phosphorylation of ...19846330034
immunoglobulin a protease activity of ureaplasma urealyticum.all of 14 serotype standards and 34 of 35 wild-type strains of ureaplasma urealyticum isolated from humans demonstrated an immunoglobulin a (iga) protease activity. this activity degraded radiolabeled human iga including iga1 but not igg or azocasein. the iga fragments were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by radioautography, and they had molecular weights of about 110,000 and 50,000. the iga protease activity persisted in 25 mm edta but was sensiti ...19846365962
effects of mycoplasma contamination on the intra-cellular free amino acid pool and exopeptidases of cultured human diploid fibroblasts. 19846379361
effect of mycoplasma infection on pyruvate dehydrogenase complex activity of normal and pyruvate dehydrogenase complex-deficient fibroblasts.the fermentative mycoplasmas a. laidlawii js, m. hyorhinis dbs-50, m. hyorhinis gdl and m. pneumoniae fh have very high apparent activities of pyruvate dehydrogenase (pdh) (ec 1.2.4.1) and pyruvate dehydrogenase complex (pdhc). infection of normal and pdhc-deficient fibroblasts with these mycoplasma species resulted in a marked increase of the specific activity of these two enzymes, and under certain conditions could conceal the enzymatic defect. the non-fermentative mycoplasmas m. salivarium vv ...19846423397
insect cell cultures in the study of attachment and pathogenicity of spiroplasmas and mycoplasmas.the insect cell lines dm-1 (drosophila melanogaster), as-2 (aceratagallia sanguinolenta) and ac-20 (agallia constricta) were infected with spiroplasmas, mycoplasmas and acholeplasma laidlawii. in dm-1 cultures maintained at 25 degrees c in m1a medium, all strains multiplied except m. hyorhinis and the uncultivable sex-ratio organism. spiroplasma citri r8a2, s. floricola bnr-1 and obmg, s. apis pps-1 and the strains bc-3, corn stunt spiroplasma (css) and 277f produced cytopathogenic effects (cpe) ...19846424527
extraction of lipids during freeze-substitution of acholeplasma laidlawii-cells for electron microscopy.cells of the bacterium acholeplasma laidlawii were rapidly frozen against a copper block cooled by liquid helium. the frozen cells were transferred to liquid nitrogen and subsequently to acetone or methanol at 183 k. after 24 h the cells were infiltrated at 203 k with a non-polar methacrylate resin of the same type as lowicryl hm20. the resin was cured at the same temperature. acetone extracted approximately 5% of the lipid content of the cells, methanol 15-45% and the resin only negligible amou ...19846429337
effects of manganese on the growth and morphology of ureaplasma urealyticum.all of the 14 serotype standard strains of ureaplasma urealyticum were inhibited to varying degrees by manganese. a 1 mm concentration of this cation either stopped growth or reduced the rate of growth in liquid medium. the presence of manganese also altered colonial morphology and cellular ultrastructure. inhibition was dose dependent and strain specific. this differential response allowed the serotype strains to be divided into two broad biotypes. for the first biotype (serotypes 1, 3, 6, and ...19846432835
the effects of ionizing radiation on the peroxide content of a pure polyunsaturated lipid dispersion and of lipids and membranes derived from acholeplasma laidlawii.dispersions of a pure unsaturated phospholipid, dilinoleoylphosphatidyl choline, formed conjugated diene hydroperoxides when irradiated in air with 7 mev electrons (150 gy and 300 gy). peroxide formation was optimized when the dispersions were irradiated in air at 37 degrees c at a dose rate of 5 gy/min. no significant loss of linoleic acid from the irradiated phospholipid dispersions was observed after doses of 150 or 300 gy. small amounts of thiobarbituric acid-reactive material were formed in ...19846607230
the effect of antibiotics against bovine mycoplasmas and ureaplasmas.a combination of lincomycin-spectinomycin-tylosin was tested against several strains of mycoplasmas and acholeplasmas as might be encountered in bovine semen and shown to be effective against them. this combination as well as minocin , rosaramicin, rosoxacin, tiamulin, gentamicin and declomycin were tested in vitro against 58 isolates of ureaplasma from the bovine urogenital tract. the lincomycin-spectinomycin-tylosin combination, minocin , rosaramicin, tiamulin and declomycin were quite active, ...19846232992
purification and properties of a manganese-containing superoxide dismutase from acholeplasma laidlawii.from the prokaryotic microorganism acholeplasma laidlawii the major manganese-containing superoxide dismutase has been purified to homogeneity, as judged by polyacrylamide gel electrophoresis. the molecular mass of the enzyme was found to be 41 500 da. it consists of two subunits of identical size and has an isoelectric point of 6.4. the enzyme contains 0.51 +/- 0.05 atoms of manganese per subunit. its amino-acid composition and light absorption spectra are presented and compared with mn- and fe ...19846469219
two cholesterol pools in acholeplasma laidlawii membranes.cholesterol exchange kinetics between [14c]cholesterol-labeled acholeplasma laidlawii and mycoplasma gallisepticum cells and phosphatidylcholine-cholesterol vesicles followed a biphasic curve, with faster exchange rates for a. laidlawii. the same biphasic curve was obtained with isolated membranes. cholesterol exchange between lipid vesicles and a. laidlawii cells depleted of phospholipids by phospholipase a2, fitted a monophasic linear curve. the data support the hypothesis that the biphasic ch ...19846479337
autoxidation of acholeplasma laidlawii membranes.autoxidation of acholeplasma laidlawii membranes (with equimolar ratio of palmitic and linoleic acid) lacks an obvious induction period, and the overall rate of disappearance of substrate does not follow closely that of typical autocatalytic kinetics. throughout the course of autoxidation, the major oxygenated products isolated were hydroperoxides (as hydroxy esters) and compounds that gave rise to trihydroxy esters. the yield of trihydroxy esters was appreciable even at the early stage of the o ...19846503621
effects of acyl chain composition on production of mycoplasmavirus mv-l2 by acholeplasma laidlawii.membrane-enveloped viruses obtain their lipid envelopes from the host cells. studies with animal viruses and different cell lines have shown that the composition of the virus envelope affects infectivity. in this study, acholeplasma laidlawii strain ja1 and the membrane-enveloped virus mv-l2 were used. in this system, it is possible to vary the "stiffness" of the host cytoplasmic membrane within a very wide range by adding different fatty acids to the growth medium. viruses with different envelo ...19846511354
calorimetric and spectroscopic studies of lipid hydrocarbon chain order in the acholeplasma laidlawii membrane.the thermotropic phase behavior of acholeplasma laidlawii b membranes, whose lipids were biosynthetically highly enriched with one of a wide variety of different types of fatty acyl groups, was studied by differential scanning calorimetry. the membrane-lipid-hydrocarbon chain orientational order of these membranes, in both the gel and liquid-crystalline states, was also investigated by 19f-nuclear magnetic resonance spectroscopy, using biosynthetically incorporated monofluoropalmitic acid probes ...19846511356
fatty acyl chain structure, orientational order, and the lipid phase transition in acholeplasma laidlawii b membranes. a review of recent 19f nuclear magnetic resonance studies.the orientational order parameters of monofluoropalmitic acids biosynthetically incorporated into membranes of acholeplasma laidlawii b in the presence of a large excess of a variety of structurally diverse fatty acids have been determined via 19f nuclear magnetic resonance (19f nmr) spectroscopy. it is demonstrated that these monofluoropalmitic acids are relatively nonperturbing membrane probes based upon physical (differential scanning calorimetry), biochemical (membrane lipid analysis), and b ...19846525566
bacterial membranes and lipid packing theory.recent physical studies on the lipids of biological membranes have emphasized the potential instability of the lamellar phase of mixtures of lipids containing unsaturated species of phosphatidylethanolamine, plasmenylethanolamine, or monoglycosyldiacylglycerols, all of which are important constituents of the membranes of different groups of prokaryotes. the polar lipid compositions of bacteria are examined in terms of lipid packing theory. this survey reveals that gram-negative species with high ...19846530599
effect of novobiocin on mycoplasma virus l2 replication.l2 is a temperate mycoplasma virus containing 11.8 kilobase pairs of negatively superhelical double-stranded dna. we observed l2 dna with less superhelicity in novobiocin-treated cells than that in untreated cells. however, although no change in viral dna superhelicity could be found in novobiocin-treated novobiocin-resistant cells, l2 production decreased in these novobiocin-treated cells.19846690717
isolation and pathogenicity of mycoplasmas from geese.several mycoplasma isolation trials were performed on infertile goose eggs and goose embryos which died during incubation, as well as on geese of different ages. a total of 43 out of 110 goose eggs proved to be contaminated by mycoplasmas. upon autopsy of birds which laid positive eggs, lesions were observed in the airsacs. mycoplasmas could be isolated from their air sacs and oviduct. four out of 15 strains examined biochemically and serologically with antisera prepared against all known avian ...19846712063
[comparative study of transformation and fusion induced by polyethylene glycol in acholeplasma laidlawii b].this study showed in acholeplasma laidlawii the possibility of transformation and fusion of protoplasts after induction by polyethylene glycol. recombination in a genome of the resistance to chloramphenicol and neomycin has been obtained. minimal inhibitory concentration of these antibiotics towards the recombined strain are identical to those measured with the parental strains. the most suitable experimental conditions have been studied. it appeared that the fusion, which is cared out more easi ...19846713302
elimination of mycoplasmas from cell cultures and establishment of mycoplasma-free cell lines.several antibiotics were examined for their potential to eliminate mycoplasmas from contaminated cell cultures. acholeplasma laidlawii, mycoplasma arginini, mycoplasma hyorhinis and mycoplasma orale were effectively eliminated from experimentally contaminated mouse fibroblasts and mink epithelial cells by the use of the antibiotics minocycline and tiamutin . an elimination procedure was established, which involved the consecutive treatment of the cultures over a period of 3 weeks, followed by ce ...19846723803
detection of mycoplasmas infecting cell cultures by dna hybridization.infection of cell cultures by mycoplasmas can be detected and the mycoplasma identified by southern blot hybridization of the eco ri-digested dna of the suspected cell cultures with a nick-translated probe consisting of cloned ribosomal rna genes of mycoplasma capricolum. the probe does not hybridize with eukaryotic dna. the hybridization pattern with mycoplasmal dna is species specific, enabling the identification of the four most prevalent mycoplasma contaminants, mycoplasma orale, mycoplasma ...19846724620
[effect of the geroprotector 2-ethyl-6-methyl-3-hydroxypyridine chlorhydrate on the cell proliferation of acholeplasma laidlawii]. 19846734406
radiation studies of acholeplasma laidlawii: the role of membrane composition.acholeplasma laidlawii, a mycoplasma, is unable to synthesize unsaturated fatty acids but it will incorporate them into its plasma membrane if they are supplied exogeneously. thus the fatty acid composition of the cell membrane can be defined by growing the organism in media containing specific fatty acids. we obtained cells with predominantly one type of unsaturated fatty acid (either oleic, linoleic or linolenic acid) or cells with only saturated fatty acid in the cell membrane. the cells were ...19836605325
characterization of the enveloped plasmavirus mvl2 after propagation on three acholeplasma laidlawii hosts.plasmavirus mvl2 was propagated on three acholeplasma laidlawii strains, ja1, s2, or bc1-13. previously reported host-controlled modification (hcm) of mvl2, as reflected by changes in plating efficiency, was observed. adsorption rates and one-step growth curves varied according to host used. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the three mvl2 populations revealed differences in polypeptide profiles.19836830442
the biosynthetic incorporation of diacetylenic fatty acids into the biomembranes of acholeplasma laidlawii a cells and polymerisation of the biomembranes by irradiation with ultraviolet light.acholeplasma laidlawii a has been grown in media containing synthetic, long chain c20- and c23-fatty acids possessing a diacetylene group in their acyl chains. growth on the c23 diacetylenic acid was poor but was good on the c20 acid. biosynthetic incorporation of the fatty acids occurs; as much as 90% of the membrane lipid fatty acyl chains consisting of the c20-diacetylenic fatty acid, the remainder being shorter chain, saturated fatty acids. the thermal phase transition of this biomembrane ha ...19836838876
membrane isolation alters the gel to liquid crystal transition of acholeplasma laidlawii b.the gel to liquid crystal phase transition of membrane lipids of live acholeplasma laidlawii b was monitored by infrared spectroscopy. it was found that, while isolated membranes are predominantly in the gel phase at the growth temperature, the live cell membranes contain a large liquid crystal phase component.19836849129
polyethylene glycol-dependent transfection of acholeplasma laidlawii with mycoplasma virus l2 dna.phenol-extracted dna from mycoplasma virus l2 was able to transfect acholeplasma laidlawii in the presence of polyethylene glycol. transfection was sensitive to dnase and was most efficient with 36% (wt/vol) polyethylene glycol 8000 and cells in logarithmic growth. virus production by the transfected cells was similar to that of the cells infected by intact virus. l2 dna transfected a. laidlawii with a single-hit dose-response curve, reaching saturation at high dna concentrations. optimum transf ...19836874642
cell culture media: contamination at flow labs. 19836888532
integration and lysogeny by an enveloped mycoplasma virus.the 11.8 kilobase pair (7.8 x 10(6) mol. wt.) genome of mycoplasma virus l2 in lysogenic acholeplasma laidlawii cells was examined. for this study, dnas were analysed by agarose gel electrophoresis and viral dna sequences identified by dna-dna hybridization. l2 dna was found to be integrated into the lysogenic host cell chromosome at a unique site in both viral and cellular dna. the viral dna site was roughly mapped and the approximate time of integration during the l2 non-cytocidal infectious c ...19836308135
[mycoplasma mastitis of cattle. 10. test of mycoplasma bovis, mycoplasma bovigenitalium and acholeplasma laidlawii for udder pathogenicity]. 19836615132
[mycoplasma mastitis of cattle. 11. histological udder findings after experimental infection with mycoplasma bovigenitalium and acholeplasma laidlawii]. 19836615133
uracil phosphoribosyltransferase from acholeplasma laidlawii: partial purification and kinetic properties.uracil phosphoribosyltransferase was purified 34-fold from sonicated extracts of acholeplasma laidlawii by ammonium sulfate precipitation, binding to deae-sephadex, sephadex g-200 chromatography, and hydroxylapatite chromatography. the molecular weight of the enzyme by gel filtration was approximately 80,000. the ph optimum for phosphoribosylation was around 7.5, and the optimum mgcl2 concentration was 5 mm. initial velocity studies were conducted over a wide range of both uracil and 5-phosphori ...19836619094
uridine phosphorylase from acholeplasma laidlawii: purification and kinetic properties.uridine phosphorylase was purified 1,370-fold from sonicated extracts of acholeplasma laidlawii by ammonium sulfate precipitation, deae-sephadex column chromatography, hydroxylapatite chromatography, and sephadex g-200 fractionation. the molecular weight of the enzyme as determined by gel filtration was approximately 65,000. [u-14c]ribose-1-phosphate (rib-1-p), prepared enzymatically from [u-14c]inosine, was utilized in initial velocity studies of uridine synthesis, which indicated a sequential ...19836619095
intraspecies genetic relatedness among strains of acholeplasma laidlawii and of acholeplasma axanthum by nucleic acid hybridization.this study compares the intraspecies genetic relatedness among strains of two established species of acholeplasma. radiolabelled dna probes were prepared from three strains of acholeplasma laidlawii and two strains of acholeplasma axanthum, by using the nick translation method. the labelled dna probes of these two strains were hybridized to an excess of unlabelled dna from 12 strains of acholeplasma laidlawii and from six strains of acholeplasma axanthum, respectively. nucleic acid hybridization ...19836631407
fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. a physical, biochemical, and biological evaluation of monofluoropalmitic acids as membrane probes.fluorine-19 nuclear magnetic resonance spectroscopy offers a number of unique advantages for studies of lipid fatty acyl chain order and dynamics in model and biological membranes. however, the germinal difluoromethylene fatty acids commonly employed as 19f membrane probes appear to appreciably perturb the organization of model membranes and biomembranes. we have thus synthesized a series of specifically labeled monofluoropalmitic acids and evaluated these as suitable membrane probes. differenti ...19836652058
fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. effects of methyl-branch substitution and of trans unsaturation upon membrane acyl-chain orientational order.the hydrocarbon-chain orientational order parameters of membranes of acholeplasma laidlawii b enriched with straight-chain saturated, methyl iso-branched, methyl anteiso-branched, or trans-unsaturated fatty acids have been determined via fluorine-19 nuclear magnetic resonance spectroscopy (19f nmr). a theoretical description of the 19f nmr spectral line shape is presented that permits the determination of the orientational order parameters associated with specifically monofluorinated palmitic ac ...19836652059
synthesis of adenylate nucleotides by mollicutes (mycoplasmas).cultures of the mollicutes (mycoplasma) acholeplasma laidlawii b, acholeplasma morum, mycoplasma bovis, mycoplasma arginini, mycoplasma fermentans and mycoplasma gallisepticum, representing four metabolic groups, were sampled at intervals over a 40 to 50 h period and assayed for the numbers of c.f.u., changes in ph and glucose concentration, and concentrations of atp, adp, amp, lactate and pyruvate. the adenylate energy charge (eca), the mean generation time, and the number of nmol of atp (mg dr ...19836655457
transport activity of mouse spleen lymphocytes after their interaction in vitro with acholeplasma laidlawii cells.transport of two non-metabolized carbohydrates (3-o-methyl-d-glucose, 3-o-mg, and 2-deoxy-d-glucose, 2-dg) into mouse spleen lymphocytes after their interaction with acholeplasma laidlawii cells has been studied. incubation of a. laidlawii cells and particularly the liposomes prepared from a. laidlawii membrane lipids enhances the rates of the both carbohydrates transport. this treatment resulted in increasing of the vmax values of 3-o-mg and 2-dg without changing the km values. this stimulation ...19836659737
[interaction of acholeplasma laidlawii and mycoplasma arthritidis with the lymphocytes of mice of different strains].the interaction of mycoplasmas and mouse lymphocytes has been studied by the microbiological and electron-microscopic methods. the experiments have shown that a. laidlawii and m. arthritidis are adsorbed on lymphocytes and thymocytes of (c57bl6 x a/he)f1, balb and c57bl mice after 15 minutes of their joint incubation at 37 degrees c, 1 hour later adsorption reaches its maximum intensity and after further prolongation of the time of incubation the number of adsorbed microbial cells remains unchan ...19836659765
[accumulation of cholesterol in acholeplasma laidlawii membranes in the steady-state phase of culture growth].in early logarithmic phase of growth of the a. laidlawii cells the lipid composition of plasma membrane is changed: the total lipid, glycolipid and phospholipid contents are decreased, while that of cholesterol changes only insignificantly. in late logarithmic and steady state phases the cholesterol level in the membrane is increased in parallel with the decrease of the phospholipid content. throughout the growth period a quantitative redistribution of membrane phospholipids in fatty acids and a ...19836661465
[instability of host-virus association in acholeplasma laidlawii infected by a mycoplasma virus of the gourlay group l1].since l 1 mycoplasmaviruses have been described by gourlay for acholeplasma laidlawii, two hypotheses tried to explain the relationships between virus and host, the first by a "gradual lysis", the second on the basis of a "reduced growth" of infected acholeplasmas. neither has implied that susceptible cells, free of virus, can be obtained from infected populations, the cells being supposed to die according to the first and to be all infected but still slowly dividing according to the second hypo ...19836675342
19f-nuclear magnetic resonance study of glycerolipid fatty acyl chain order in acholeplasma laidlawii b membranes.the technique of 19f-nuclear magnetic resonance (19f-nmr) spectroscopy offers a number of advantages for studies of lipid fatty acyl chain orientation and dynamics in biomembranes. however, the geminal difluoromethylene fatty acid probes usually employed in such studies appreciably perturb the organization of lipid bilayers. we have thus synthesized a series of specifically monofluorinated palmitic acids and carried out biophysical, biochemical, and physiological studies establishing their suita ...19836679141
survey of plasmids in various mycoplasmas.thirty-three strains representing 15 distinct mycoplasma, acholeplasma, and spiroplasma species were examined for the presence of plasmid dna by agarose gel electrophoresis. the electrophoretic patterns of the dnas of three strains, mycoplasma sp. strain 747, spiroplasma mirum strain smca, and m. hominis strain 1257, suggested the presence of a plasmid with molecular weights of approximately 70, 10, and 9 megadaltons, respectively. the functions of these plasmids are currently unknown.19836679154
persistence of acholeplasma laidlawii in an established cell line rl 19. 1. host-parasite morphology.the cell-parasite relationship of epitheloid cells from the established liver cell line rl 19 persistently infected with acholeplasma laidlawii was studied by transmission electron microscopy and scanning electron microscopy. the predominantly filamentous, branched a. laidlawii were arranged horizontally on the cell surface between microvilli at the cell margin. the cell adhesion, spreading, growth pattern and cell surface shape were not altered in relation to uninfected cultures of the same cel ...19836685661
interspecies and intraspecies dna homology among established species of acholeplasma: a review.radiolabeled dna probes prepared in vitro by the nick translation method were used to determine the nucleotide sequence homology among the eight established and one unclassified species of acholeplasma. very little dna homology (2 to 21 percent) was found among these nine distinct species and the heteroduplexes showed at least 15 percent mismatching as determined by thermal elution endpoints. the data obtained by hybridization analyses paralleled the results obtained by the growth inhibition and ...19836433583
binding of mvl-2 virus to a. laidlawii cells.binding of mvl-2 virus, whose envelope lipids were radioactively labeled, to a. laidlawii ja1 cells was determined and characterized. the binding followed first-order kinetics and was temperature-dependent. all mvl-2 particles were capable of binding to a. laidlawii cells. at least 75 percent of radioactive mvl-2 bound represented specific binding which was markedly inhibited by edta. virus infectivity was not essential for binding as inactivation of the virus by ultraviolet irradiation did not ...19836433585
[the pathogenic properties of acholeplasma in experiments in guinea pigs]. 19836400777
extraction of membrane lipids during fixation, dehydration and embedding of acholeplasma laidlawii-cells for electron microscopy. 19836405040
mycoplasmal infection of insect cell cultures.twenty-five cell cultures of three insect orders from eight laboratories were tested for mycoplasmal infection. acholeplasma laidlawii was detected in one culture, an incidence of 4.0%. a. laidlawii, mycoplasma orale, m. arginini, but not m. hyorhinis, could establish infections of drosophila dm-1 cell cultures at 25 degrees c. in prospective studies, drosophila dm-1 cultures were intentionally infected with broth-propagated a. laidlawii and m. hyorhinis. m. hyorhinis did not grow and was elimin ...19836413389
polyacrylamide gel electrophoresis: recovery of non-stained and stained proteins from gel slices.following electrophoresis or isoelectric focusing in gels of polyacrylamide the protein band of interest is cut out and placed above a sucrose gradient column, containing carrier ampholytes (pharmalyte). by electrophoresis, isoelectric focusing or displacement electrophoresis the proteins migrate out of the gel slice and into the isoelectric focusing column for concentration and further purification. from this column, the proteins can be withdrawn and their isoelectric points determined. even af ...19836187792
purification and characterization of the membrane (na+ + mg2+)-atpase from acholeplasma laidlawii b.the membrane (na+ + mg2+)-atpase of acholeplasma laidlawii b has been solubilized with a brij-58/sodium deoxycholate mixture and purified by a combination of gel filtration and ion-exchange chromatography. the purified, partially delipidated atpase has a specific activity of 195 mumol pi/mg protein per h, which could be enhanced by 25% upon the addition of exogenous phospholipids. the kinetic properties of the purified enzyme are similar to those of the native membrane-bound enzyme, suggesting t ...19836138096
origins of the mycoplasmas: sterol-nonrequiring mycoplasmas evolved from streptococci.we report the establishment of a phylogenetic relationship between the sterol-nonrequiring mycoplasmas (acholeplasma species) and streptococci. three specific antisera prepared against purified streptococcus faecalis fructose diphosphate aldolase and glyceraldehyde-3-phosphate dehydrogenase and pediococcus cerevisiae glyceraldehyde-3-phosphate dehydrogenase were used for comparative enzyme immunological studies; the ouchterlony double-diffusion technique and the quantitative microcomplement fixa ...19826176574
elucidation of the antigenic architecture of the acholeplasma laidlawii cell membrane by immunoabsorption in combination with crossed immunoelectrophoresis.immunoabsorption in combination with crossed immunoelectrophoresis was used for elucidation of the antigenic architecture of the acholeplasma laidlawii cell membrane. when cells were grown in a medium containing cholesterol and unsaturated fatty acids, the cell membranes became fragile. membrane proteins or membrane fragments, which under some conditions seemed to be enriched in specific proteins (especially protein t2), were released into the growth medium. therefore, most of the experiments we ...19826181548
molecular properties of membrane lipids and activity of a membrane adenosine triphosphatase from acholeplasma laidlawii b.the effects of membrane lipid fluidity and phase state on enzyme activity were evaluated by careful analysis of arrhenius plots of the na+, mg2+-dependent adenosine triphosphatase (referred to hereafter as atpase) from acholeplasma laidlawii b membranes and differential thermal analysis of the membrane lipid phase transitions. arrhenius plots of the atpase activity in membranes containing only liquid-crystalline lipids are gently curved and have the same form regardless of the membrane fatty liv ...19826214837
[proteins of bacterial membranes. h+-adenosinetriphosphatase from acholeplasma laidlawii cells].the cytoplasmic membrane of micoplasmic cells, in particular of a. laidlawii cells, contains a proton-carrier mg2+ -activated atpase. a whole h+ -atpase complex (f0-f1) was isolated from these cells and characterized. the isolation procedure included solubilization of the enzyme with triton x-100 followed by ion-exchange chromatography on deae-cellulose and gel filtration on sepharose 6b. the enzyme was inhibited by dicyclohexylcarbodiimide (10(-4) m). the km value for atp hydrolysis and ki for ...19826123348
effects of pressure and pressure antagonists on the growth and membrane-bound atp-ase of acholeplasma laidlawii b.1. arrhenius plots of the membrane-bound atp-ase were constructed at pressures of 300, 600 and 900 atm. pressure shifts the plots to higher temperatures with an increase in slope. 2. these data are partially consistent with a kinetic model in which a phase transition in the lipids associated with the atp-ase determines the activity of the enzyme. they are also consistent with a model in which the non-linear arrhenius plot is caused by the low temperature inactivation of the enzyme, upon which pr ...19826125309
cytosine methylation of the sequence gatc in a mycoplasma.mycoplasma virus l2 is subject to host-specific restriction and modification in acholeplasma laidlawii strains ja1 and k2. we have examined the dnas from both host cells and viruses propagated on these strains with respect to susceptibility to cleavage by restriction endonucleases and for dna base modifications. we show that, in strain k2 and l2 virus grown on k2 cells, cytosine in the sequence gatc is methylated to 5-methylcytosine and, although strain k2 and l2 viruses grown on k2 contain n6-m ...19826286600
ribosomal rna genes in mycoplasma.using southern blotting analysis with labelled mycoplasmal ribosomal rna as probe, two fragments (1 kb and 5 kb) were detected in an ecor i digest of mycoplasma capricolum dna. this analysis revealed that the 5 kb fragment carries both 16s rrna sequences and the entire 23s rrna gene of this mycoplasma. the 1 kb fragment contains 16s rrna sequences only. the 5 kb ecor i fragment has been cloned and used to characterize the structure of rrna cistrons in various mycoplasma strains. these experiment ...19826289267
receptor sites for mycoplasmal viruses on acholeplasma laidlawii.all three groups of mycoplasmal viruses tested, mvl1, mvl2, and mvl3, were inactivated by both membranes and lipoglycan from acholeplasma laidlawii strain ja1. the interaction was specific for components of a. laidlawii since no inactivation occurred with either membrane or lipoglycan from acholeplasma oculi. adsorption of virus was proved by the demonstration of radiolabeled virus-lipoglycan or virus-membrane particles that were separable in density gradients from either component alone. recept ...19826289406
cholesterol and phospholipid uptake by mycoplasmas.mycoplasma offer several unique advantages for investigating the mechanism controlling transfer and uptake of exogenous cholesterol and phospholipids by biomembranes, as their plasma membrane interacts directly with exogenous lipid donors and their endogenous lipid synthesis is restricted. growing cells of five species of mycoplasma were found to take up significant quantities of phosphatidylcholine and sphingomyelin as well as free and esterified cholesterol. in contrast, growing cells of three ...19826289408
molecular organization and selective solubilization of lipids and proteins in the envelope of mycoplasmal virus l2.the composition and molecular organization of mycoplasmal virus l2 (mvl2) were studied and compared with those of the cell membrane of the host, acholeplasma laidlawii strain ja1. the virus contained 0.2-0.25 mumol of polar lipids per mg of viral protein. the lipid species of the mvl2 were the same as those of the host cells. nevertheless, the proportions between the various polar lipids were different, with a much lower content of phosphatidylglycerol in the viral lipids. despite these quantita ...19826289409
monoclonal antibodies specific for cell culture mycoplasmas.mycoplasma infection of cell cultures is still a major problem in some laboratories. although several methods can be used for their detection, identification is normally by serological procedures. as no commercial source for the necessary antibodies is available we have prepared monoclonal antibodies to the five mycoplasma species that account for the majority of cell culture infections. these antibodies have been characterized by the growth inhibition test (git), immunofluorescence, and enzyme ...19826811415
properties of the nucleases of mollicutes.extracts of the mollicutes acholeplasma equifetale, acholeplasma laidlawii b, mycoplasma arthritidis. mycoplasma pulmonis, and mycoplasma pneumoniae had dnase and endonuclease activity. a. laidlawii b had at least two peaks of dnase activity in sucrose gradients with sedimentation coefficients of 3.1s and 4.3s. these fractions also had endonuclease activity with different substrate specificities. a. laidlawii b may have more than two peaks of endonuclease activity in sucrose gradients.19826811565
isolation of acholeplasmas and a mycoplasma from vegetables.the isolation of mollicutes from food has not been reported. to isolate mollicutes in the presence of high levels of unwanted bacteria, we first incubated fresh vegetables in liquid culture media containing lysozyme, ampicillin, and thallous acetate. culture fluids were than separated from the vegetable samples, subjected to one freeze-thaw cycle, and passed through a filter of 0.4-micron porosity. filtered samples were cultured in sp4 medium and in a conventional medium containing horse serum. ...19827036899
adsorption of the tailed mycoplasma virus l3 to cell membranes.the adsorption properties of the tailed bacteriophage l3 to acholeplasma laidlawii cells were studied. adsorption followed a biphasic curve. reversibility and virus heterogeneity were not sufficient to explain the break in the adsorption curve. binding studies showed that each colony-forming unit could bind about 350 virions. the electrostatic nature of l3 adsorption was indicated by the effect of cations, ph, and temperature on the adsorption rate constant. l3 adsorption appeared to have a requ ...19827042999
the use of differential scanning calorimetry and differential thermal analysis in studies of model and biological membranes.differential scanning calorimetry (dsc), and to a lesser extent differential thermal analysis (dta), are powerful yet relatively rapid and inexpensive thermodynamic techniques for studying the thermotropic phase behavior of lipids in model and biological membranes, without the introduction of exogenous probe molecules. in this review the principles as well as the scope and limitations of dsc and dta are discussed first. the application of these techniques to the study of the thermotropic phase b ...19827046969
immunological and functional activity of spleen lymphocytes from mice infected by acholeplasma laidlawii cells and rauscher virus.the duration of acholeplasma laidlawii antigen persistence in mice, resistant to rausher leukemia virus, after infection with both a. laidlawii cells and rausher virus has been studied. the antigen persistence was accompanied by marked depression of immune response which was especially severe in case of mixed acholeplasmavirus infection. such immunosuppression and observed infiltration of the spleen with immature leukemic cells can be regarded as a preleukosis. immunosuppression was accompanied ...19827048811
isolation of acholeplasma laidlawii from a giraffe (giraffa camelopardalis rothschildi) and a mouflon (ovis musimon). 19827064318
comparison of ciliostasis by mycoplasmas in mouse and chicken tracheal organ cultures.the cilia-stopping effect of mycoplasmas of human and various animal origin in mouse and chicken tracheal organ cultures was studied. from the results in mouse tracheal organ cultures, the mycoplasma strains tested were divided into three groups: mycoplasma pulmonis m53, m pulmonis jb, m. pulmonis ok, m. mycoides subsp. mycoides pgl and m. gallisepticum s6 showed a strong cilia-stopping effect; m. pulmonis pg22, m. mycoides subsp. capri pg3, m. meleagridis 19729, m. neurolyticum type a and m. ar ...19827087799
effects of cholesterol on the orientational order of unsaturated lipids in the membranes of acholeplasma laidlawii. a 2h-nmr study.we have investigated by 2h-nmr the effects of the incorporation of cholesterol on the orientational order of unsaturated lipid acyl chains in the membranes of acholeplasma laidlawii b. this is the only 2h-nmr study to date of the influence of cholesterol in a biological membrane using specifically labelled fatty acids. we observed the characteristic condensing effect of cholesterol on the lipid acyl chain order in the liquid crystalline phase. in terms of the percentage increase in the quadrupol ...19827093275
isolation and identification of mycoplasmas from the respiratory tract of the white leghorn chicken in the sudan. 19827093655
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