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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
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
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
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 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 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
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
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
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
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
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 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
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
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
spiroplasma membrane lipids.membranes of six spiroplasma strains belonging to different spiroplasma species and subgroups were isolated by a combination of osmotic lysis and sonication in the presence of edta to block endogenous phospholipase activity. analysis of membrane lipids showed that in addition to free and esterified cholesterol the spiroplasmas incorporated exogenous phospholipids from the growth medium. sphingomyelin was preferentially incorporated from phosphatidylcholine-sphingomyelin vesicles or from the seru ...19852981796
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
affinity labeling of the (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes by the 2',3'-dialdehyde derivative of adenosine 5'-triphosphate.the (na+ + mg2+)-atpase of the acholeplasma laidlawii b plasma membrane was inactivated by the 2',3'-dialdehyde derivative of atp (oatp). oatp behaved as a reversible competitive inhibitor of this atpase and was slowly hydrolyzed by the enzyme. in addition, oatp induced an irreversible inactivation of the enzyme. a 62% inactivation of the enzyme correlated with the binding of 16 moles of oatp per mole of the enzyme. in the presence of 5'-adenylyl imidodiphosphate, a non-hydrolyzable substrate an ...19853155967
structural relatedness of three ion-transport adenosine triphosphatases around their active sites of phosphorylation.three membrane-bound adenosine triphosphatases were investigated for homology in the sequence of four amino acids about the active site of phosphorylation. the atpases were as follows: sodium-potassium-dependent atpase from dog kidney, na,k-atpase; hydrogen-potassium-dependent atpase from hog gastric mucosa, h,k-atpase, an atpase similar to na,k-atpase; and an atpase activity in the plasma membrane of corn, zea mays, roots (cr-atpase), a higher plant atpase. a membrane preparation containing an ...19853156136
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
selective acylation of membrane proteins in acholeplasma laidlawii.in membranes of the cell-wall-less prokaryote acholeplasma laidlawii most proteins are of the integral type. a substantial fraction of these proteins are enriched in hydrophilic amino acid residues. approximately 20 different major as well as minor proteins were found to be covalently modified with acyl chains. the same set of proteins are acylated when cells are grown in different fatty-acid-supplemented media. in individual proteins the ratio of palmitoyl/oleoyl acyl chains was 12-14 times lar ...19862420589
phagocytosis of mycoplasma pneumoniae and acholeplasma laidlawii measured as inhibition of [3h]uridine uptake by macrophages.many studies of the interaction between phagocytes and mycoplasmas have given controversial results. this is probably due both to the small size of the microorganisms and their ability to attach to the cell membrane, making it difficult to distinguish between adsorption and ingestion. to overcome these difficulties we took advantage of a phenomenon we noted occurring concomitantly with phase-contrast microscope-monitored phagocytosis of heat-killed c. albicans, i.e., a reduction of [3h]uridine u ...19862424998
comparative studies to determine the efficiency of 6 methylpurine deoxyriboside to detect cell culture mycoplasmas.studies were performed to compare three methods to detect mycoplasmal infection of cell cultures. the methods included microbiological assay by inoculation into broth and onto agar with anaerobic incubation, fluorescent dna staining by hoechst 33258, and mycoplasmal mediated cytotoxicity by 6 methylpurine deoxyriboside (6mpdr). fluorescent dna staining and 6mpdr assays were performed in an indicator cell culture system. a total of 2589 cell cultures were assayed. mycoplasmas were detected in 174 ...19862428802
[decontamination of continual cell lines spontaneously infected with mycoplasmas].the continual cell lines of bovine kidneys mdbk and aubek, and porcine kidneys rpd and ibrs, spontaneously infected with mycoplasma arginini and acholeplasma laidlawii, were decontaminated by the method of selective elimination. two elimination procedures were modified to be used for the decontamination: one based on the reduction of infection by the light treatment of the cultures, the other based on the selection of mycoplasma-free cell population through cell clonation. on the basis of a long ...19863090766
probable insensitivity of mollicutes to rifampin and characterization of spiroplasmal dna-dependent rna polymerase.the effect of rifampin on five mollicutes (spiroplasma citri, spiroplasma melliferum, spiroplasma apis, acholeplasma laidlawii, and mycoplasma mycoides) was compared with that on escherichia coli. we found that, in contrast to wild-type e. coli, mollicutes were insensitive to rifampin. dna-dependent rna polymerases from s. melliferum and s. apis were purified to the stage where the enzymes were dependent on the addition of exogenous templates for activity. the enzymes were then tested for their ...19863519581
interaction of polyene antibiotics with membrane lipids: physicochemical studies of the molecular basis of selectivity.from various studies on the interaction of amphotericin b with unilamellar lipid vesicles, it appears that the strength of the binding does not depend only on the presence of sterol molecules in the membranes; and that several bound amphotericin b species are in competition, their relative amounts depending on the nature and percentage of sterol in the lipid bilayer. bound amphotericin b molecules exchange rapidly between the membranes. it is therefore possible to add the antibiotic by transfer ...19863527632
[ribosomal genes--the only homologous dna segments in mycoplasmas]. 19863537771
how do the polyene macrolide antibiotics affect the cellular membrane properties?in the 1970's great strides were made in understanding the mechanism of action of amphotericin b and nystatin: the formation of transmembrane pores was clearly demonstrated in planar lipid monolayers, in multilamellar phospholipid vesicles and in acholeplasma laidlawii cells and the importance of the presence and of the nature of the membrane sterol was analyzed. for polyene antibiotics with shorter chains, a mechanism of membrane disruption was proposed. however, recently obtained data on unila ...19863539192
mycoplasma restriction: identification of a new type of restriction specificity for dna containing 5-methylcytosine.mycoplasma bacteriophage l51 single-stranded dna and l2 double-stranded dna are host cell modified and restricted when they transfect acholeplasma laidlawii ja1 and k2 cells. the l51 genome has a single restriction endonuclease mboi site (recognition sequence gatc), which contains 5-methylcytosine when the dna is isolated from l51 phage grown in k2 cells but is unmethylated when the dna is from phage grown in ja1 cells. this gatc sequence is nonessential, since an l51 mutant in which the mboi si ...19863001023
ppi-dependent phosphofructotransferase (phosphofructokinase) activity in the mollicutes (mycoplasma) acholeplasma laidlawii.a ppi-dependent phosphofructotransferase (ppi-fructose 6-phosphate 1-phosphotransferase, ec 2.7.1.90) which catalyzes the conversion of fructose 6 phosphate (f-6-p) to fructose 1,6-bisphosphate (f-1, 6-p2) was isolated from a cytoplasmic fraction of acholeplasma laidlawii b-pg9 and partially purified (430-fold). ppi was required as the phosphate donor. atp, datp, ctp, dctp, gtp, dgtp, utp, dutp, itp, ttp, adp, or pi could not substitute for ppi. the ppi-dependent reaction (2.0 mm ppi) was not al ...19863001032
effects of mercury (ii) compounds on the activity of dutpases from various sources.the deoxyuridine triphosphate nucleotidohydrolases (dutpases, ec 3.6.1.23) from escherichia coli k-12-,acholeplasma laidlawii b-pg9-, human kb cell-, and the herpes simplex virus (hsv) type 1- and 2-induced dutpases were purified and used to determine the effect of various mercury (ii) compounds on their activities. mercuric acetate, 5-mercuri-dutp (hgdutp), and 5-mercuri-dctp (hgdctp) acted as irreversible active site-directed inhibitors of the dutpases purified from eukaryotic organisms but no ...19863005836
[role of the membranes in lymphocyte interaction with mycoplasmas].the interaction of acheleplasma laidlawii cells, derived membranes and liposomes with mouse spleen lymphocytes does not require the energy and participation of electrostatic coupling. the absence of pinocytosis of mycoplasma is demonstrated. specific membrane receptors don't participate in mycoplasma and lymphocyte binding. the exchange by membrane lipids occurs during the interaction of mycoplasma, membranes and liposomes with lymphocytes; mycoplasma, membranes and liposomes lose saturated fat ...19863028509
structure-function investigations of the membrane (na+ + mg2+)-atpase from acholeplasma laidlawii b: studies of reactive amino acid residues using group-specific reagents.the purified, lipid-reconstituted (na+ + mg2+)-atpase from acholeplasma laidlawii b was treated with a variety of reagents which specifically modify various amino acid residues on the enzyme. in all cases reaction of this enzyme with any of the reagents tested results in at least a partial inactivation of its activity. the modification of one reactive lysine by dinitrofluorobenzene, of one reactive arginine by phenylglyoxal, or of two tyrosine residues by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole ...19862939801
decontamination of cell lines by selective elimination of mycoplasmas. 19863964004
[effect of acholeplasma laidlawii on the bacterial infection of white mice]. 19863964006
transmembrane electrical potential affects the lipid composition of acholeplasma laidlawii.in membranes of acholeplasma laidlawii, lipid composition is regulated as a function of several stimuli affecting the volume and length of the hydrocarbon chains and the hydrocarbon-water interfacial area. this regulation is vizualized as changes in the relative amounts of the major polar lipids monoglucosyl diglyceride and diglucosyl diglyceride. these lipids form reversed hexagonal and lamellar phases with water, respectively. however, mixtures of the two lipids, in the molar proportions found ...19863964647
extraction of proteins and membrane lipids during low temperature embedding of biological material for electron microscopy.the extraction of proteins and membrane lipids from biological materials during embedding procedures for electron microscopy carried out at temperatures down to 223 k was studied. glutaraldehyde-fixed cells of acholeplasma laidlawii mainly served as test material. more than 99% of the protein and 88% of the lipid of these cells were retained after dehydration with ethanol or acetone between 277 and 223 k and infiltration with methacrylate at 223 k. when methanol was used for dehydration, only 54 ...19863712423
ultrastructural changes in mollicutes induced by the peptide antibiotic herbicolin a.electron microscopy of negatively stained mycoplasma, ureaplasma, and acholeplasma cells showed ultrastructural changes after 10 min of treatment of the organisms with the peptide antibiotic herbicolin a in concentrations ranging from 10 micrograms/ml for mycoplasma capricolum to 600 micrograms/ml for ureaplasma urealyticum. the morphological changes were shown to be reversible at low concentrations of the antibiotic but irreversible at high concentrations.19863717939
cholesterol uptake capacity of acholeplasma laidlawii is affected by the composition and content of membrane glycolipids.the composition of the cell membrane of 20 acholeplasma laidlawii strains grown under identical conditions was studied and correlated with the capacity of these strains to incorporate cholesterol. membranes of these strains had similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns and contained the same lipid species, but the relative amounts of the major polar lipids varied. statistical analyses revealed that the glycolipids, monoglucosyldiglyceride, and an unidentified gly ...19863729418
isolation of mycoplasma virus l2 insertion variants and miniviruses.we isolated two spontaneous variants of mycoplasma virus l2. both variants, designated l2ins1 and l2ins2, contained a 3.1-kilobase-pair (kbp) insertion in the 11.8-kbp wild-type l2 genome. the insert dna was shown to be derived from two noncontiguous regions of the l2 genome, and l2ins1 and l2ins2 differed only in the location of the 3.1-kbp insertion. we also isolated l2 miniviruses from serial passages of l2, l2ins1, and l2ins2 viruses. miniviruses contained circular dna molecules of 3.1 kbp o ...19863735491
adsorption of mycoplasmavirus mv-l2 to acholeplasma laidlawii: effects of changes in the acyl-chain composition of membrane lipids.the enveloped mycoplasmavirus mv-l2 and its host acholeplasma laidlawii ja1 were used to study the ways in which changes in the membrane lipid bilayer affect virus adsorption. the physical state of the membranes was altered by (i) using viruses and bacteria with different membrane lipid acyl-chain compositions, (ii) using incorporation of cholesterol, and (iii) changing the temperature. adsorption of viruses was strongly dependent on the acyl-chain composition of the virus and the host. adsorpti ...19863773051
phase equilibria of membrane lipids from acholeplasma laidlawii: importance of a single lipid forming nonlamellar phases.a basis for the reorganization of the bilayer structure in biological membranes is the different aggregate structures formed by lipids in water. the phase equilibria of all individual lipids and several in vivo polar lipid mixtures from acyl chain modified membranes of acholeplasma laidlawii were investigated with different nmr techniques. all dioleoyl (do) polar lipids, except monoglucosyldiglyceride (mgdg), form lamellar liquid crystalline (l alpha) phases only. the phase diagram of domgdg rev ...19863801429
metabolic changes of membrane lipid composition in acholeplasma laidlawii by hydrocarbons, alcohols, and detergents: arguments for effects on lipid packing.the packing of lipids into different aggregates, such as spheres, rods, or bilayers, is dependent on the hydrophobic volume, the hydrocarbon-water interfacial area, and the hydrocarbon chain length of the participating molecules, according to the self-assembly theory [israelachvili, j. n., marcelja, s., & horn, r. g. (1980) q. rev. biophys. 13, 121-200]. the origin of the participating molecules should be of no importance with respect to their abilities to affect the above-mentioned parameters. ...19863801430
chromosome analysis by two-dimensional fingerprinting.a two-dimensional fingerprinting technique has been developed that allows large, cell genome-size dna's to be analyzed by restriction endonuclease cleavage and separation of dna fragments by agarose gel electrophoresis. equations have been derived to determine the genome size and number of cleavage sites from analysis of the distribution of fragment lengths. genome sizes of escherichia coli strain jm101 and two strains of the mycoplasma acholeplasma laidlawii measured by this method are in agree ...19863032749
synthesis of deoxyribomononucleotides in mollicutes: dependence on deoxyribose-1-phosphate and ppi.cell extracts of acholeplasma laidlawii b-pg9, acholeplasma morum s2, mycoplasma capricolum 14, and mycoplasma gallisepticum s6 were examined for 37 cytoplasmic enzyme activities involved in the salvage and biosynthesis of purines. all of these organisms had adenine phosphoribosyltransferase activity (ec 2.4.2.7) and hypoxanthine phosphoribosyltransferase activity (ec 2.4.2.8). all of these organisms had purine-nucleoside phosphorylase activity (ec 2.4.2.1) in the synthetic direction using ribos ...19873038846
anti-mycoplasmal activity of a new macrolide: miocamycin.the object of this study was the evaluation of the activity of miocamycin and other macrolides (erythromycin and josamycin) against 61 ureaplasma urealyticum, 1 acholeplasma laidlawii and 21 aerobe mycoplasmas (m. pneumoniae, m. hominis, m. gallisepticum, m. mycoides) and anaerobe mycoplasmas (m. morale and m. salivarium) both clinically isolated and standard reference strains. the minimum inhibitory concentrations (mic) values for miocamycin ranged between 0.00625 mg/l and 0.4 mg/l (ureaplasmas ...19873501335
cloning and expression of acholeplasma laidlawii membrane acyl proteins in escherichia coli.many integral membrane proteins in acholeplasma laidlawii are enriched in hydrophilic amino acid residues and covalently modified with fatty acids. in order to understand how these proteins are inserted and anchored in the bilayer, we have cloned several of the major a. laidlawii proteins in escherichia coli: 900 recombinant clones containing 4-kbp dna fragments, inserted into the bamhi site of the plasmid pat 153, were screened with antibodies. with antimembrane antibodies, 26 positive clones w ...19873312093
[detection and identification of mycoplasma infections by dna hybridization].infection of cell cultures by mycoplasmas can be detected by hybridization of the dna of suspected cell cultures with recombinant plasmids containing fragments of the mycoplasma dna. the test is very sensitive and allows detection of as little as 1 ng of mycoplasmal dna, roughly equivalent to the dna amount of 10(6) mycoplasmas. this approach turns out to be effective for detection and identification of mycoplasmas in clinical material, plant and insect tissues. a set of dna probes for detection ...19873318046
reconstitution of the purified (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes into lipid vesicles and a characterization of the resulting proteoliposomes.the purified (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes was reconstituted with dimyristoylphosphatidylcholine using a cholate solubilization and dialysis procedure. the incorporation of this enzyme into the phospholipid bilayer is accompanied by an enhancement of its specific activity and by a restoration of its lipid phase state-dependent properties which were lost during solubilization and purification from native membranes. moreover, reconstitution of this atpase with phospho ...19872958088
lipid modulation of the activity and temperature dependence of the purified (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes.the influence of lipid composition on the activity and temperature dependence of the purified (na+ + mg2+)-atpase from acholeplasma laidlawii b membranes has been investigated. the reconstituted enzyme requires liquid-crystalline lipid for full activity. however, phosphatidylcholines with fatty acids varying considerably in chemical structure and chain length all support comparable levels of activity at temperatures above their gel to liquid-crystalline phase transition temperatures, indicating ...19872959635
method for exchange of the lipid environment of the membrane-bound (mg2+ + na+)-atpase of acholeplasma laidlawii b.a method that exchanges the endogenous lipids in the environment of the membrane-bound (mg2+ + na+)-atpase of acholeplasma laidlawii b with defined exogenous lipids has been devised. results demonstrate that 99.9% of the original membrane lipids were replaced with phosphatidylcholine and phosphatidic acid. atpase enzyme activity was maintained throughout the substitution procedure.19872960250
endonuclease from acholeplasma laidlawii strain ja1 associated with in vivo restriction of dna containing 5-methylcytosine.transfection of acholeplasma laidlawii strain ja1 with viral dnas that have been sequence-specifically methylated in vitro has led us to previously postulate that ja1 cells contain an enzyme which cleaves only dna containing 5-methylcytosine, regardless of the nucleotide sequence containing that base. in this paper we show that an endonuclease activity is present in extracts from ja1 cells but not in extracts from a restriction-deficient variant of ja1. the partially purified enzyme cleaves not ...19872822609
transposition of gram-positive transposon tn916 in acholeplasma laidlawii and mycoplasma pulmonis.mycoplasma genetics has been limited by a lack of genetic tools such as selectable markers, methods to transfer dna, and suitable vectors for cloning. studies were undertaken to examine the potential of using the streptococcal transposon tn916 as a mycoplasma genetic tool. the escherichia coli plasmid pam120, which contains tn916, was transformed into acholeplasma laidlawii and mycoplasma pulmonis. transposition of tn916 into the mycoplasma chromosome apparently occurred by an excision-insertion ...19873029869
enzymological features of aromatic amino acid biosynthesis reflect the phylogeny of mycoplasmas.acholeplasma laidlawii possesses a biochemical pathway for tyrosine and phenylalanine biosynthesis, while mycoplasma iowae and mycoplasma gallinarum do not. the detection of 7-phospho-2-dehydro-3-deoxy-d-arabino-heptonate (dahp) synthase (ec 4.1.2.15), dehydro-shikimate reductase (ec 1.1.1.25) and 3-enol-pyruvoylshikimate-5-phosphate synthase (ec 2.5.1.19) activities in cell-free extracts established the presence in a. laidlawii of a functional shikimate pathway. l-phenylalanine synthesis occurs ...19872895162
lipid acyl chain-dependent effects of sterols in acholeplasma laidlawii membranes.acholeplasma laidlawii was grown with different fatty acids for membrane lipid synthesis (saturated straight- and branched-chain acids and mono- and di-unsaturated acids). the ability of 12 different sterols to affect cell growth, lipid head group composition, the order parameter of the acyl chains, and the phase equilibria of in vivo lipid mixtures was studied. the following two effects were observed with respect to cell growth: with a given acyl chain composition of the membrane lipids, growth ...19873027049
membrane potential, lipid regulation and adenylate energy charge in acyl chain modified acholeplasma laidlawii.in acholeplasma laidlawii variations induced in the transmembrane electrical potential have been shown to affect the membrane lipid composition. particularly the molar ratio between the predominant glucolipids, monoglucosyldiacylglycerol and diglucosyldiacylglycerol, decreases upon hyperpolarization and increases upon depolarization (clementz et al. (1986) biochemistry 25, 823-830). upon variation of the degree of membrane fatty acyl chain unsaturation, known to affect the passive permeability f ...19873567184
activities of oxidative enzymes in mycoplasmas.the activities of several oxidoreductases were measured in three fermentative and two nonfermentative mycoplasma species that were grown under aerobic or anaerobic conditions. acholeplasma laidlawii mg, mycoplasma hyorhinis gdl, and mycoplasma pneumoniae fh had very high apparent activities of pyruvate dehydrogenase and pyruvate dehydrogenase complex compared with the activities of mammalian fibroblasts or human platelet-enriched preparations, while mycoplasma salivarium vv and mycoplasma arthri ...19873571159
mapping of mycoplasma virus dna replication origins and termini.a pulse-labeling protocol has been used to study dna replication and map replication origins and termini in mycoplasma viruses l2 and l2ins1. the l2 genome is circular, double-stranded dna of 11.63 kilobase pairs (kb), and the 14.89-kb l2ins1 genome is l2 dna containing a 3.26-kb insertion. the data show that dna replication is bidirectional from two origins in l2 and three origins in l2ins1. the extra origin in l2ins1 arises from the fact that one of the l2 origins is in one of the sequences th ...19873573152
cytotoxic and cytolytic activity of nonadecafluoro-n-decanoic acid on acholeplasma laidlawii.we studied the interactions between the perfluorinated fatty acid nonadecafluoro-n-decanoic acid (ndfda) and the cell wall-less procaryote acholeplasma laidlawii, which were cultured in an identical medium base but with different serum supplements. when grown in mycoplasma media supplemented with pplo serum fraction (difco laboratories, detroit, mich.), a. laidlawii was rapidly killed by low concentrations of toxicant (less than 1.0 mm). at higher concentrations (greater than 10 mm), ndfda treat ...19873606106
isolation of acholeplasmatales from rabbit faeces.acholeplasma laidlawii was isolated from the faeces of 23.5% and 24% of groups of 51 conventional and 45 specified-pathogen-free (spf) rabbits respectively. isolation of the organism from individual animals could often be repeated, suggesting that infection was not merely transient. two further acholeplasmas were isolated from two spf rabbits. one was serologically related to acholeplasma modicum. the other could not be identified and may be a new species.19873626465
the role of lipids in the interaction of acholeplasma laidlawii cells with lymphocytes.the role of a. laidlawii membrane lipids in the organism's interaction with mouse spleen lymphocytes is analyzed. a. laidlawii cells were grown in a lipid-poor medium with unsaturated fatty acids that allowed cells with different degrees of membrane lipid microviscosity to be obtained. the intensity of the binding of a. laidlawii cells and derived liposomes with lymphocytes depended directly on the degree of fatty acid unsaturation. cholesterol incorporation into the a. laidlawii membrane reduce ...19873630470
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