transport properties of membrane vesicles from acholeplasma laidlawii. ii. kinetic characteristics and specificity of glucose transport system.the glucose transport system of membrane vesicles isolated from acholeplasma laidlawii is saturable, with a km of 21.2 mum and v of 0.68 nmol min-1 (mg protein)-1. the process is ph-dependent and a break occurs in the arrhenius plot at 15 degrees c. exogenous substrates did not stimulate glucose transport probably due to their inability to penetrate into membrane vesicles. 3-o-methylglucose and 6-deoxyglucose competitively inhibited glucose transport. maltose inhibited transport of glucose nonco ...1975286
properties of the 3-o-methyl-d-glucose transport system in acholeplasma laidlawii.transport of 3-o-methyl-d-glucose (3-o-mg) by acholeplasma laidlawii cells was studied. the 3-o-mg transport system appeared to be constitutive in cells grown on 3-o-mg and glucose; the transport process depended on the concentration of substrate used and exhibited typical saturation kinetics, with an apparent km of 4.6 mum. 3-o-mg was transported as a free carbohydrate and was not metabolized further in the cell. dependence on ph and temperature and the results of efflux and "counterflow" exper ...19761368
variation in distribution of membrane particles in acholeplasma laidlawii b with ph. 19764629
surface balance study of the interaction between microorganisms and lipid monolayer at the air/water interface.using the surface balance technique, we have compared the interaction between acholeplasma laidlawii and some marine bacteria towards different types of monolayered lipid films. cells from a. laidlawii and serratia marinorubra penetrate the film, whereas cells from psuedomonas fluorescens form a layer underneath the film. the forces that bind microorganisms to the air/water interface are not strong enough to scatter a condensed monolayer but increase the strength of loosely packed monolayers.19765058
cultivation of mycoplasmas in a modified tissue culture medium.a new medium, which contained a chemically defined tissue culture base ("medium 199"), was developed for the cultivation of mycoplasmas. when supplemented with albumin, glucose, serum, and yeast extract, the new medium adequately supported the growth of mycoplasma and acholeplasma species.19767199
detection of serum proteins in the electrophoretic patterns of total proteins of mycoplasma cells.the contamination of mycoplasma cell preparations by serum proteins originating from culture medium was studied. a. laidlawii and m. arthritidis cells were grown in the presence of 14c-aminoacids, and the cells were washed with 0-9% nac1 by threefold centrifugation. total proteins of the washed cells were analysed by sds gel electrophoresis. coomassie-stained electrophoretic patterns were compared with autoradiographs of the same gels. the stained electrophoretic pattern of washed a. laidlawii g ...197610333
reduced nicotinamide adenine dinucleotide oxidase activity in membranes and cytoplasm of acholeplasma laidlawii and mycoplasma mycoides subsp. capri.the properties of the membrane-bound reduced nicotinamide adenine dinucleotide (nadh) oxidase of acholeplasma laidlawii were compared with those of the corresponding cytoplasmic activity of mycoplasma mycoides subsp. capri. the striking differences in ph optima, susceptibility to inhibitors and detergents, and heat inactivation between the nadh oxidase activity, with oxygen as an electron acceptor, and the nadh oxidoreductase activity, with dichlorophenol indophenol (dcpip) as an alternate elect ...197611208
microcalorimetric detection of growth of mycoplasmatales.a static ampoule microcalorimeter was used to study the growth of mycoplasmas, acholeplasmas and ureaplasmas. growth as indicated by thermograms was compared with the results of conventional methods, namely, terminal dilution counts, plate counts, turbidimetric measurements, glucose consumption and ph changes. removal of oxygen had little effect on mycoplasma growth. the microcalorimetric method is potentially useful for identifying and enumerating the members of the mycoplasmatales.197611273
localization of enzymes in ureaplasma urealyticum (t-strain mycoplasma).ureaplasma urealyticum cells were lysed by osmotic shock or by digitonin. the membrane fraction contained four to ten times as much protein as the cytoplasmic fraction. these values are in large excess of those reported for classical mycoplasmas, suggesting that the ureaplasma membrane fraction was heavily contaminated with proteins derived from the growth medium. the u. urealyticum urease activity was localized in the cytoplasmic fraction, whereas the adenosine triphosphatase activity was local ...197715980
fractionation of membrane proteins by hydrophobic interaction chromatography and by chromatography on agarose equilibrated with a water-alcohol mixture of low or high ph. 197825906
symport h+/carbohydrate transport into acholeplasma laidlawii cells. 197826600
effect of ammonium ion concentration and osmotic pressure on growth of ureaplasma urealyticum (t-strain mycoplasma).the effect of ammonium ion concentration and osmotic pressure on growth of ureaplasma urealyticum type viii was determined by using a well-buffered broth medium containing 10 mm urea. the addition of nh4cl to the medium at concentrations up to 10 mm did not affect growth; however, addition of larger quantities progressively decreased both the specific growth rate (mu) and the maximum yield of the culture, with concentrations of 80 mm completely inhibiting growth. addition of either 150 mm kcl or ...197826668
physiological role and membrane lipid modulation of the membrane-bound (mg2+, na+)-adenosine triphosphatase activity in acholeplasma laidlawii.the membrane-bound adenosine triphosphatase (atpase) activity of acholeplasma laidlawii b differs in many respects from the common (mg2+, ca2+)-atpase activity of higher bacteria, most notably in that it is specifically activated by mg2+ and strongly and specifically stimulated by na+ (or li+). various inhibitors diminish the atpase activity with a concentration dependence which suggests that a single enzyme species is responsible for all of the observed atp hydrolytic activity (both basal and n ...197831351
[glucose induced transport of h+, k+ and lactate in the cells of acholeplasma laidlawii].currents of h+ and k+ ions initiated under the effect of facultative anaerobe of a. laidlawii, valinomycin, nigericin and carbonyl cyanide chloride phenylhydrasone on the membrane are recorded by means of the system of cation sensitive electrodes. it is stated that during glucose transport a redistribution of h+ and k+ and lactate between the cellular content and the medium takes place. preincubation of cells with 3-o-methyl-d-glucose essentially decreases the effect of induced ion transport. it ...197935239
size and shape of mycoplasma virus mv-lg-l 172 dna.sedimentation of dna of mycoplasma virus mv-lg-l 172 in neutral and alkaline density gradients showed that the chromosome of this virus is most probably formed by a double-stranded circular dna molecule with a molecular weight of approx. 10(7) daltons. these results were confirmed by direct electron microscopy of the viral dna. gamma-irradiation of the virus caused in its dna single breaks on the average per each 66 ev of absorbed energy. virus survival depended exponentially on the irradiation ...197835941
the pathogenicity of avian mycoplasmas.based on literature data and own experiences the author gives an outlook about pathogenicity of avian mycoplasmas. in chickens and turkeys m. gallisepticum and m. synoviae (in addition to it m. meleagridis exclusively in turkeys) are the most important mycoplasmas producing respiratory disease, inflamation of synovial membranes and other lesions. their pathogenic effect is very much influenced by dose of agent, route of entry of microorganism, age of birds, virulence and tropism of organism as w ...197944612
complement-mediated killing of acholeplasma laidlawii by antibodies to various membrane components.mycoplasmas are useful models for biochemical studies of the mechanism of complement-mediated killing by antibodies to various membrane components. the purpose of this study was to determine the membrane antigens involved in immune killing of acholeplasma laidlawii. antibodies to a. laidlawii membrane total lipids, glycolipids, and phospholipids could be induced in rabbits after injection of reaggregates of the purified lipids with mycoplasma hominis protein as the carrier. killing of a. laidlaw ...197661175
keratitis and acholeplasma laidlawi. 197661420
ultrastructural and cytochemical studies on anionic surface sites of mycoplasma membranes.negatively charged, chemical groups on the surfaces of mycoplasma membranes were studied in the electron microscope by staining with positively charged ferric oxide hydrosols in the acetic acid (ai-reagent) or propanoic acid (pi-reagent), respectively. the technique of thin sectioning was used. with the ai-reagent, no significant binding of the ferric oxide particles was observed on the mycoplasma membranes. with the lipophilic pi-reagent, the membrane surfaces of m. mycoides subsp. capri, m. my ...197765876
effect of various culturing conditions of acholeplasma laidlawii on the yield and properties of the cells and cell membrane.acholeplasma laidlawii strain b cell cultured in complex medium have an optimal temperature of growth at 31 degrees. maximal growth at this temperature is 80% higher than at 37 degrees. by stirring of the culture, the yield of the cell mass of 4 liter-cultures increases by 200%. with these modifications the yield of cell membranes increases 3--4 times with respect to that of static culturing at 37 degrees. membranes obtained from better aerated cultures have a lower flavin and carotenoid content ...197767754
demonstration by electron microscopy of intracellular virus in acholeplasma laidlawii infected with either mv-l3 or a similar but serologically distinct virus (bn1 virus).cultures of acholeplasma laidlawii strain m1305/68 were inoculated with mycoplasmatales virus-laidlawii 3 (mv-l3) and examined by electron microscopy. particles resembling mv-l3 were observed both intra- and extracellularly in thin sections prepared from mv-l3 infected cultures, but not from uninfected cultures. similar particles were occasionally observed in uninoculated cultures of a. laidlawii strain bn1 cells, from which a virus (bn1 virus) was subsequently isolated. this virus was morpholog ...197984856
mycoplasma contamination in cell culture of crohn's disease material. 197989521
role of cholesterol in the action of cereolysin on membranes. 1978102256
the nature and location of acholeplasma laidlawii membrane proteins investigated by two-dimensional gel electrophoresis.the high resolution, two-dimensional electrophoresis system for the separation of proteins described by o'farrell, (o'farrell, p.h. (1975) j. biol. chem. 250, 4007--4021) has been modified for the separation of acholeplasma laidlawii proteins. reproducible protein patterns have been obtained from a. laidlawii cell, membrane and soluble protein preparations. the isoelectric focusing of membrane proteins was greatly improved by removing the bulk of the membrane lipid before solubilizing the protei ...1978102346
in vitro antimycoplasmal activity of mepartricin.the in vitro antimycoplasmal activity of mepartricin was evaluated on several mycoplasma strains. the results demonstrate that this polyene antibiotic possesses a high efficacy against these microorganisms.1979118890
transport properties of membrane vesicles from acholeplasma laidlawii. i. isolation and general characteristics.a new procedure for the isolation of membrane vesicles from acholeplasma laidlawii cells is described. the membrane vesicles are completely free from contaminations of whole cells and cell debris and represent a homogeneous fraction as shown by electron microscopy, ficoll density-gradient centrifugation, and titration on agar plate. absence of cytoplasmic contaminations was confirmed by double-labelling of membranes with 3h-oleic acid and 14c-uridine, as well as by distribution of specific marke ...1975127739
antibiotics for elimination of mycoplasmas and ureaplasma from bovine semen.minocin at 500 micrograms/ml of semen extender eliminated ureaplasma from naturally or artificially infected bovine semen. minocin with lincospectin eliminated acholeplasma laidlawii, mycoplasma bovigenitalium, bovis, canadense, and arginini from artificially infected semen. stabilization times of 15 min at 35 c and 3 h at 4 c are important considerations to maximize antibiotic activity.1977141466
membrane enzymes: artifacts in arrhenius plots due to temperature dependence of substrate-binding affinity.for the membrane sodium-stimulated magnesium-adenosinetriphosphatase of acholeplasma laidlawii b both the vmax and km values in the michaelis equation very strongly with temperature. simulations of arrhenius plots show that an enzyme with a temperature-dependent km can yield a variety of arrhenius plot artifacts, most notably erroneous "breaks," if activity is assayed at a fixed substrate concentration.1978146257
the effect of high hydrostatic pressure on the membrane-bound atp-ase of acholeplasma laidlawii b [proceedings]. 1979160925
[infectious keratoconjunctivitis of cattle in ivory coast. i. microbiological aspects]. 1975174165
phosphorus nuclear magnetic resonance of acholeplasma laidlawii cell membranes and derived liposomes.1. the 129 mhz 31p-nmr spectrum of acholeplasma laidlawii membranes is very similar to the spectrum of the derived liposomes and is a typical "solid state" spectrum in which the major contribution to the linewidth is made by the chemical shift anisotropy. from the value of the chemical shift anisotropy an order parameter of 0.15 is estimated for the lipid phosphates in both membranes. 2. the 31p-nmr spectrum of the a. laidlawii membrane is insensitive to pronase digestion of 4-60% of the membran ...1976174728
action of polymyxin b on bacterial membranes: phosphatidylglycerol- and cardiolipin-induced susceptibility to polymyxin b in acholeplasma laidlawii identify the polymyxin receptor molecules in the membranes of living microorganisms, fusion of intact acholeplasma laidlawii b with lipid vesicles was investigated according to the procedure of grant and mcconnell (1973). the naturally polymyxin-resistant a. laidlawii b was treated with phospholipid vesicles prepared from purified phospholipids of the polymyxin-susceptible salmonella typhimurium g30. a. laidlawii b absorbed between 15 and 45% of its own lipid content of the added tritium-labe ...1976176930
the reduced nicotinamide adenine dinucleotide "oxidase" of acholeplasma laidlawii nadh dehydrogenase possessing a specific activity 3-5 times that of membrane-bound enzyme was obtained by extraction of acholeplasma laidlawii membranes with 9.0% ethanol at 43 degrees c. this dehydrogenase contained only trace amounts of iron (suggesting an uncoupled respiration), a flavin ratio of 1:2 fad to fmn and 30-40% lipid. its resistance to sedimentation is probably due to the high flotation density of the lipids. it efficiently utilized ferricyanide, menadione and dichlorophenol ind ...1976177076
thermotropic transitions in biomembranes. 1976182064
recognition of different pools of phosphatidylglycerol in intact cells and isolated membranes of acholeplasma laidlawii by phospholipase a2.phospholipase a2 (ec from pig pancreas hydrolyzes phosphatidylglycerol in intact cells and isolated membranes of acholeplasma laidlawii. complete degradation of phosphatidylglycerol in intact cells at 37 degrees c does not result in lysis as shown by the retention of intracellular k+ ions and the cytoplasmic glucose-6-phosphatase, as well as the inability to detect activity of membrane-bound intracellular nadh-oxidase. a. laidlawii was grown on linoleic acid. phospholipase a2 treatment ...1977191065
cholesterol transfer from serum lipoproteins to mycoplasma membranes. 1977199249
[experimental infection of dogs with myocplasmas (acholeplasma laidlawii)]. 1977202113
acholeplasma laidlawii membranes: an electron spin resonance study of the influence on molecular order of fatty acid composition and cholesterol. 1978216314
purification and properties of acetate kinase from acholeplasma laidlawii.acetate kinase (ec was purified from acholeplasma laidlawii cytoplasm by a combination of ammonium sulfate fractionation, gel filtration, diethylaminoethyl-cellulose chromatography, and affinity chromatography on 8-(6-aminohexylamino)-adenosine 5'-triphosphate conjugated to sepharose 4b. the enzyme was composed of polypeptide chains of about 50,000 molecular weight as estimated from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. under nondenaturating conditions, apparent mol ...1979217865
the ayerst award lecture 1978. organization and dynamics of membrane lipids as determined by magnetic resonance spectroscopy. 1979218704
activities of enzymes of purine and pyrimidine metabolism in nine mycoplasma species. 1979232630
characterization of the mycoplasma membrane proteins. v. release and localization of membrane-bound enzymes in acholeplasma laidlawii.the peripheral membrane protein fraction released by washing acholeplasma laidlawii membranes with low-ionic strength buffers contained about 50% of the total membrane-bound ribonuclease and deoxyribonuclease activities. the atpase, nadh oxidase and p-nitrophenylphosphatase activities remained bound to the membrane even when edta was added to the wash fluids, and thus appear to belong to the integral membrane protein group. serving as a marker for peripheral membrane proteins, the membrane-bound ...1975234252
electron-microscopic study of a mycoplasmatales virus, strain mv-lg-ps2-l 172.morphology and adsorption of a globular virus, lysing acholeplasma laidlawii were studied in ultrathin sections of plaques in a lawn of the host strain. the virus was globular, about 50 to 90 nm in diameter, with a clearly defined membrane, 6.5 to 8 nm thick. a protuberance about 25 to 35 nm long and 12 to 20 nm thick was observed on numerous virus particles. the evenly granulated, electron-optically dense content of the cells became clearer in cells affected by the viruses. fibrillar structures ...1975234904
differential fluorescence labelling with 5-dimethyl-aminonaphthalene-1-sulfonyl chloride of intact cells and isolated membranes in salmonella typhimurium and acholeplasma laidlawii.for fluorescence labelling intact cells and isolated cell envelopes (membranes) from salmonella typhimurium and acholeplasma laidlawii were treated with mixed dansylchloride-lecithin-cholesterol vesicles. this kind of dansylation, which has been supposed to be specific for cell surface proteins, produced fluorescent protein pattern after sds-polyacrylamide gel electrophoresis only when isolated envelopes were dansylated. acid hydrolysis of fluorescent cell envelopes of salmonella typhimurium yie ...1975235245
[glucose transport into membrane vesicles from acholeplasma laidlawii cells]. 1975235409
purification of membrane proteins from acholeplasma laidlawii by agarose suspension electrophoresis in tween 20 and polyacrylamide and dextran gel electrophoresis in detergent-free media.four of the membrane proteins from acholeplasma laidlawii that are soluble in the nonionic detergent tween 20 have been purified by preparative electrophoretic techniques utilizing different supporting media. the last purification step for two of the major proteins was a preparative polyacrylamide gel electrophoresis performed in the absence of any detergent. the proteins were recovered by continuous elution. the purity of the fractions was examined by analytical polyacrylamide gel electrophores ...1975235514
electron diffraction studies of biological membranes and lipids. 1975235744
[identification of mycoplasmas isolated from monkeys].the authors identified 15 strains of mycoplasmae isolated from papio hamadryas suffering from leukemia and from healthy macacus rhesus, a green monkey and saimiri. a study was made of their biochemical properties, antigenic properties in the reaction of growth depression with immune sera to a number of standard strains, and also the protein composition by electrophoresis in polyacrylamide gel (epag). a number of mycoplasmae were identified as a. laidlawii, m. arthritidis--campo and m. cynomolgus ...1975235821
adenine formation from adenosine by mycoplasmas: adenosine phosphorylase activity.mammalian cells have enzymes to convert adenosine to inosine by deamination and inosine to hypoxanthine by phosphorolysis, but they do not possess the enzymes necessary to form the free base, adenine, from adenosine. mycoplasmas grown in broth or in cell cultures can produce adenine from adenosine. this activity was detected in a variety of mycoplasmatales, and the enzyme was shown to be adenosine phosphorylase. adenosine formation from adenine and ribose 1-phosphate, the reverse reaction of ade ...1975236559
immunogenetic analysis of the mechanism of induction of friend virus leukemia. 1975236610
scanning of polyacrylamide gel electrophoresis columns for detection of unstained protein zones and for their localization relative to enzyme activities. 1975236684
crossed immunoelectrophoresis: polyacrylamide gel electrophoresis followed by electrophoresis into an agarose gel containing antibodies. 1975236696
osmotic behaviour of acholeplasma laidlawii b cells with membrane lipids in liquid-crystalline and gel state.the osmotic behaviour of acholeplasma laidlawii b cells was investigated with combined spectrophotometric and enzymatic measurements. the conclusion could be drawn that this osmotic behaviour depends largely on the physical state of the membrane lipids. when part of the membrane lipids is in the liquid-crystalline phase the cell is able to swell and behaves as a good osmometer. however, when the membrane lipid is in the gel phase, the cell is unable to swell and the change in absorbance of the c ...1975236790
glucose transport in acholeplasma laidlawii b: dependence on the fluidity and physical state of membrane lipids.the uptake of d-glucose by acholeplasma laidlawii b occurs via a mediated transport process, as shown by the following observations: (i) glucose permeates a. laidlawii b cells at a rate at least 100 times greater than would be expected if its entry occurred only by simple passive diffusion; (ii) the apparent activation energy for glucose uptake in a. laidlawii is significantly lower than that expected and observed for the passive permeation of this sugar; (iii) glucose uptake appears to be a sat ...1975237881
heterogeneity in the physical state of the exterior and interior regions of mycoplasma membrane lipids. 1975238513
membrane lipid, not polarized water, is responsible for the semipermeable properties of living has recently been proposed that the semipermeable surface barrier of living cells is in fact provided by water polarized in multilayers by the cellular protein, and not by the lipids of the cell membrane as had been widely supposed. this review paper summarizes a large and diverse body of recent experimental work, concerned with the structure and function of biological membranes in general and with the passive permeability properties of cell surface membranes in particular, which does not sup ...1975238671
determination of membrane properties at the molecular level by carbon-13 and deuterium magnetic resonance. 1978279301
ultrastructural localization of tellurite reduction in acholeplasma species.aerobic reduction of tellurite by five acholeplasma species and two mycoplasma species was investigated by light and electron microscopy. among the acholeplasma species, colonies of a. laidlawii and a. oculi exhibited a heavy, macroscopically visible reduction of tellurite, whereas the reaction of a. axanthum was weaker. a. granularum and a. modicum did not reduce the substrate under the experimental conditions employed. the two subspecies of m. mycoides also reacted with tellurite, as did also ...1977329638
localization of a phosphoglycolipid in mycoplasma membranes using specific anti-lipid-antibodies.a phosphoglycolipid, presumably identical to glyceryl-phosphoryldiglycosyl diglyceride, is the main component of the membrane glycolipids of mycoplasma mycoides subsp. capri. it is immunologically active. anti-phosphoglycolipid antibodies were induced in rabbits by intravenous injection of the flocculated complexes of methylated bovine serum albumin with a mixture of the phosphoglycolipid and the auxiliary lipids, phosphatidyl-choline and cholesterol. the specificities of the antibodies directed ...1977337735
bristol laboratories division, bristol-myers company, syracuse, n.y. 1978348086
acid-soluble nucleotides of acholeplasma (mycoplasma) laidlawii a.a study was made of the acid-soluble nucleotides present in acholeplasma (mycoplasma) laidlawii a during growth. the nucleotide pool of this organism is meagre, both qualitatively and quantitatively. the main nucleotides are uridine mono- and diphosphates, and none of the more complex nucleotide compounds, such as uridine diphosphate (udp) sugars or sugar peptides, required for cell wall formation, were detected. the nucleotide composition of a. laidlawii a is compared with that of the streptoco ...1978358744
mechanisms of thermophily. 1978365460
simplified preparation of mycoplasmas, an acholeplasma, and a spiroplasma for scanning electron microscopy.a simple, effective procedure was developed for scanning electron microscopic examination of mycoplasmas and similar organisms. cultivation of several mycoplasmal species, an acholeplasma, and a spiroplasma in broth media in leighton tubes with cover slips resulted in attachment of the organisms to the cover slips. the attached cells were easily processed for either scanning electron microscopy or light microscopy. by eliminating the need for centrifugation, which was used in previously describe ...1979370106
comparative studies between microbiological culture and uptake of uridine/uracil to detect mycoplasmal infection of cell cultures. 1979376320
alteration of colonial morphology of acholeplasma laidlawii and acholeplasma modicum by infection with mycoplasmatales viruses.morphologically aberrant colonies resulted from the infection of acholeplasma laidlawii with two of its three known viruses and from acholeplasma modicum cells naturally carrying virus. the patterns of colonial alteration differed between cells infected with the two a. laidlawii viruses. colonies derived from single cells infected with the bullet-shaped virus mv-l1 (mycoplasmatales virus-laidlawii-1) had a radial sectoring pattern of intracolonial swellings ("blebs"), whereas cells infected with ...1979378947
[comparative study of rosette and plaque formation in rats infected with mycoplasma arthritidis and acholeplasma laidlawii].m. arthritidis suppresses rosette- and plaque-formation in rats infected with this strain of mycoplasma. on the 15th day the immune response was restored in the control and experimental groups of animals. in later stages a strong stimulation of rfc and pfc was recorded, which levelled on day 150. on the contrary, a. laidlawii stimulated rfc and pfc in all stages of infection. a relationship between the phenomena described and pathogenic properties of the mycoplasma is discussed.1979380687
[action of mycoplasma arthritidis and acholeplasma laidlawii on the immunological reactivity of balb/c mice infected with the rauscher leukemia virus]. 1979389300
growth of an enveloped mycoplasmavirus and establishment of a carrier state.the growth of an enveloped dna-containing mycoplasmavirus (mvl2 obtained from r.n. gourlay) has studied, by using the indicator host acholeplasma laidlawii strain ja1. from virus one-step growth curves, artificial lysis experiments, and infected cell growth curves, it was found that virus infection is nonlytic. newly infected cells grow slower and are osmotically more stable than uninfected cells. however, 4 to 6 h after infection, the cells reach a carrier state in which cell growth rate and os ...1977405508
alteration by cereolysin of the structure of cholesterol-containing membranes.when erythrocyte membranes were treated with cereolysin, negatively stained and examined by electron microscopy, ring and arc-shaped structures were observed in the membrane. the outside diameter of the rings varied from 33 to 50 nm with a border thickness of 6.7 to 8.3 nm. the arcs varied in length from 33 to 170 nm with a border thickness of also 6.7 to 8.3 min. when right-side-out erythrocyte ghosts which had been treated with cereolysin were examined by electron microscopy after freeze-fract ...1978414780
physical characterization of the superhelical dna genome of an enveloped mycoplasmavirus.mycoplasmavirus mvl2 is a nonlytic enveloped virion containing dna. this dna has been shown to be a double-stranded circular superhelical molecule of 11.8 kilobase pairs (7.8 x 10(6) daltons). the superhelix density is greater than that of phi x174 rfi but less than that of pm2 phage dna. a physical map of the mvl2 genome has been obtained using restriction endonucleases.1979430595
characterization of mycoplasmavirus mvl2 dna.the size and molecular configuration of mycoplasmavirus mvl2 dna are presented. the dna was shown to be a covalently closed circular duplex molecule with a molecular weight of 7.4 x 10(6). in sucrose gradients at neutral ph, the form i and form ii dna molecules have sedimentation values of approximately 29s and 23s, respectively. under alkaline conditions, the form i and form ii have s values of 70 and 20, respectively.1979430596
studies on classification of acholeplasmas isolated from horses, cattle and abattoir sewage. 1979430937
the properties of gel state lipid in membranes of acholeplasma laidlawii as observed by 2h nmr. 1979437110
is the vertical disposition of mycoplasma membrane proteins affected by membrane fluidity?the influence of the physical state of the membrane lipid matrix on the vertical disposition of membrane proteins was studied with acholeplasma laidlawii. changes in membrane fluidity were brought about by altering the fatty acid composition of membrane lipids, by changing the growth temperature, by aging of cultures and by inducing changes in the membrane lipid-to-protein ratio through treatment with chloramphenicol. the lactoperoxidase-mediated iodination technique was used to label membrane p ...1979444513
role of lipid fatty acyl composition and membrane fluidity in the resistance of acholeplasma laidlawii to complement-mediated killing. 1979448140
[lipid regulation of carbohydrate transport system in mycoplasma].cultivation of acholeplasma laidlawii cells in media containing unsaturated fatty acids results in changes of the physiological state of the membrane lipid bilayer due to preferable incorporation of an unsaturated fatty acid into lipids. the lipids are capable to regulate the transport activity since the transport rates for glucose, 3-o-methyl-c-glucose, glucerol and erythritol change considerably when the cells are cultivated in media containing different unsaturated fatty acids. the transport ...1979454709
the use of the anti-acholeplasma activities of streptomyces culture filtrates for the screening of new antibiotics.a screening method for new antimicrobial agents from streptomyces culture filtrates was developed. three different types of test organisms were used for determining the antimicrobial activities of the culture filtrates: they were (a) an antibacterial activity test against staphylococcus aureus, (b) an antimycoplasmal activity test against acholeplasma laidlawii, and (c) a cytotoxicity test against hela-s3 cells. the active filtrates showing antimicrobial spectra (anticellogram) which did not mat ...1979462473
on the interaction between intrinsic proteins and phosphatidylglycerol in the membrane of acholeplasma laidlawii. 1979464610
replication of mycoplasmavirus mvl51: vi. acriflavine stimulates growth of this single-stranded dna virus. 1979486185
lipid distribution in acholeplasma laidlawii membrane. a study using the lactoperoxidase-mediated iodination.the lactoperoxidase-mediated radioiodination has been applied to study the transbilayer distribution of phospho- and glycolipids in acholeplasma laidlawii membranes. after radioiodination, about 5% of the 125i-iodine was found in membrane lipids. a comparison of the labeling intensities of the various lipid species between iodinated intact cells and isolated membranes revealed that the glycolipids monoglucosyldiglyceride and diglucosyldiglyceride are located almost exclusively in the outer half ...1979486468
prevalence of mycoplasmal bovine mastitis in species of mycoplasma plus one or more unknown species were found to cause bovine mastitis in california. both the frequency of cases and number of species of mycoplasma in samples received at the laboratory have increased from 1976 to 1978. by survey, nearly 4% of samples of bulk tank milk from dairy farms were found to contain mycoplasma of potential pathogenic significance. acholeplasma laidlawii was frequently isolated from samples both from cows and from farm bulk tanks during wet, ra ...1979507492
unusual positional distribution of fatty acids in phosphatidylglycerol of sterol-requiring mycoplasmas. 1979510549
composition and molecular organization of lipids and proteins in the envelope of mycoplasmavirus mvl2.mvl2 virus was purified from culture supernatants of infected acholeplasma laidlawii cells by differential centrifugation, followed by velocity centrifugation in sucrose gradients. the purified virus contained 0.08 to 0.1 mumol of lipid phosphorous per ml of viral protein. thin-layer chromatography of viral lipids revealed the presence of phospho-, glyco-, and phosphoglycolipids identical with those found in the host cell membrane, but the relative amount of phosphatidylglycerol was much lower t ...1979513201
comparison of mycoplasmatales virus mv-lg-ps2-l172 with plasmavirus mv-l2 and the other mycoplasma viruses.mycoplasma virus mv-lg-ps2-l172 was sensitive to heat (56 degrees c/30 minutes), nonidet-p40 and ether. in these respects it resembled plasmavirus mb-l2. however, it differed from mv-l2 (and the other mycoplasma viruses, mv-l1, mv-l3 and bn1 virus) in reciprocal plaque inhibition and serum neutralization tests (mv-l2 only). by plaque formation on host lawns resistant to the different mycoplasma viruses, including mv-lg-ps2-l172, this latter virus was shown to be distinct from the other viruses, ...1979518304
studies on bacterial cell wall inhibitors. vi. screening method for the specific inhibitors of peptidoglycan synthesis.a screening method was established for selecting new specific inhibitors of bacterial cell wall peptidoglycan synthesis. in the primary test, culture broths of soil isolates were selected based on relative microbial activity. a culture, to be retained, must be active against bacillus subtilis and lack activities against acholeplasma laidawii. in the secondary test, inhibitors of bacterial cell wall synthesis were identified by their ability to prevent the incorporation of meso-[3h]diaminopimelic ...1979528376
carotenoids acts as reinforcers of the acholeplasma laidlawii lipid bilayer.acholeplasma laidlawii cells grown with oleic acid produced much more colored carotenoids than did cells grown with elaidic acid. the amount of carotenoids was decreased 80 to 90% by growing the cells with 0.05 m propionate, resulting in a marked increase in the mobility of both 5-doxylstearate and 12-doxylstearate incorporated into the membranes. the fatty acid composition of the propionate-grown cells differed from that of cells grown without propionate by containing odd-numbered rather than e ...1979533770
scanning electron microscopy of acholeplasma colonies on agar.the colony formation and morphology of acholeplasma laidlawii and of an acholeplasma species was studied by scanning electron microscopy. in the colonies of both acholeplasma spp. large irregularly shaped cells, spherical cells, chains of beads, and long filaments with small bulbous distensions were seen. the membrane of some of the large cells seemed to be perforated, giving the cell a pitted appearance.1979534959
structural and biological properties of mycoplasmavirus mvl3: an unusual virus-procaryote interaction.the kinetics of adsorption and growth of mycoplasmavirus mvl3 in acholeplasma laidlawii 1305/68 host cells have been studied with one-step growth, premature lysis, and single-burst experiments. the virus was found to kill infected host cells. virus release starts 90 min after infection and continues for about 10 to 15 h. hence, virus production is unlike the classical lytic bacteriophages and instead resembles nonlytic cytocidal animal viruses. structural details of the virus are described, and ...1979541825
binding of lectins to membranes of mycoplasmas from aging cultures.the binding of iodinated concanavalin a (con a) and ricinus communis agglutinin (rca) to intact cells and isolated membranes of acholeplasma laidlawii, mycoplasma hominis and mycoplasma capricolum decreased with the progression of the culture from the mid- to the late-logarithmic phase of growth. the binding of the lectins to acholeplasma laidlawii membranes had no significant effect on membrane fluidity, as assessed by electron-paramagnetic resonance spectroscopy of spin-labelled fatty acids, a ...1979542135
[studies of mycoplasma mastitis in cattle. 5. studies of udder pathogenicity of mycoplasma and acholeplasma strains of different origins].isolated acholeplasma laidlawii strains exhibited highly differentiated behaviours regarding their udder pathogenicity. twelve of 16 tested strains were pathogenic to udder. symptoms of acute udder inflammation were caused by all ten a. laidlawii strains isolated from differentiated material of calf, but by only two of six strains isolated from differentiated material of cattle. intracisternal instillation of both strains from milk and one strain each from udder skin or cervical mucus caused mer ...1979547917
[studies of mycoplasma mastitis in cattle. 6. testing of mycoplasma isolated from milk for udder pathogenicity].strains of m. bovis, a. laidlawii, a. axanthum, and one unidentified strain of the family of mycoplasmataceae as well as altered secretion obtained from cows with mastitis were intracisternally applied in experiments and proved to be pathogenic to cattle udder. the results are likely to suggest the importance of mycoplasma isolated from the milk of mastitis cows to the aetiology of enzootic mastitis in three large dairy cattle stocks. intravenous application of m. bovis and a. laidlawii caused n ...1979547918
[studies of mycoplasma mastitis in cattle. 7. mycoplasma mastitis in 3 dairy cattle herds].reported in this paper is the occurrence of enzootic mastitis in three dairy cattle stocks. the outbreaks had been caused by mycoplasma bovis, acholeplasma laidlawii, acholeplasma axanthum as well as by one unidentified strain of the family of mycoplasmataceae. all animals with positive response to mycoplasma tests were identified an selected by repetitive testing of cultures in milk samples which had been taken from all lactating and dry cows and heifers as well as by evaluation of organ sample ...1979547919
[mycoplasma mastitis in cattle].reported in this paper are experiments from which the conclusion was drawn that acheloplasma laidlawii could cause changes in the mammary gland under certain circumstances.1979551753
[experience in identification and control of mycoplasma in dairy cattle stock under routine laboratory conditions].exacting demands have to be met by milk testing routine laboratories where mycoplasma species are to be cultured from milk samples. cleanliness of sampling, immediate cold storage, and no-delay transport of the milk samples to the testing centre are of greatest importance to the informative value of all mycoplasma tests. in the summer season, it is recommended to freeze the milk samples immediately after sampling. mycoplasma broth should not be inoculated to animals of the herd from which the sa ...1979551756
[acholeplasma laidlawii--a pathogenic or apathogenic species?].the question is discussed, whether acholeplasma laidlawii is a pathogenic or apathogenic species. studies have shown that it is a species of potential pathogenicity, however, with virulence properties differing greatly by strains. nothing so far has become known of contributive factors which might be needed for an infectious disease to develop.1979551758
heterogeneity among strains of mycoplasmatales virus-laidlawii 2.five isolates of mycoplasmatales virus-laidlawii 2 (mv-l2) derived from bovine strains of acholeplasma laidlawii were shown to differ in host range, plaque morphology and neutralization tests with mv-l2 antiserum. cross-testing using virus resistant clones of a. laidlawii confirmed the heterogeneity of this group. adaptation of viruses to sub-optimal host was demonstrated.1977560426
lymphocyte activation by various mycoplasma strains and species.the capacity of various mycoplasma strains and species to induce lymphocyte transformation in vitro was studied. of six strains of mycoplasma pulmonis studied, five displayed mitogenic activity with rat lymphocytes. among those m. pulmonis strains, our mp15 isolate and the negroni strain exhibited particularly potent mitogenic capacity. the murine mycoplasmas m. neurolyticum and m. arthritidis shared this mitogenicity for rat lymphocytes. however, the human mycoplasmas m. fermentans, m. pneumoni ...1977562852
endogenous hprt activity in mycoplasmas isolated from cell cultures.five mycoplasma species most frequently isolated from cell cultures were tested for the presence of endogenous hypoxanthine phosphoribosyl-transferase (hprt) activity. all of the five, cultured in cell-free medium, contained variable but significant levels of hprt. two strains of m. hyorhinis exhibited a 13-fold difference in their specific hprt activity. when infected with any of these mycoplasma species, hprt-deficient mouse cell mutants rapidly acquired a cell-associated hprt activity; howeve ...1978569123
[experimental infection of mice, gerbils, and rats with mycoplasms from canine pericardium and cardial value (author's transl)].mycoplasms isolated from heart valves (a. laidlawii (a 42 hzbtl)) and pericardium (m. canis (a 56 hzkl)) of dogs were investigated for infectivity of rats, mice and gerbils (meriones unguiculatus). in mice the species m. spumans (pg 13), m. maculosum (pg 15), m. edwardii (pg 24) and m. molare (h 542) were investigated too. the mycoplasmas were inoculated by oral, subcutaneous, intravenous and intraperitoneal route. intraperitoneally the mycoplasmas were given without and with complete and incomp ...1977595971
membrane lipid biosynthesis in acholeplasma laidlawii b: elongation of medium- and long-chain exogenous fatty acids in growing cells.the chain elongation of a wide variety of exogenous fatty acids and the subsequent incorporation of the chain elongation products into the total membrane lipids of acholeplasma laidlawii b were systematically studied. within each chemical class of fatty acids examined, the extent of chain elongation increased with increases in chain length, reached a maximum value, and then declined with further increases in chain length. depending on chemical structure, exogenous fatty acids containing less tha ...1978618849
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