Publications

the influence of the fatty acid composition of acholeplasma laidlawii membranes on the growth inhibitory activity of narasin, a polyether ionophorous antibiotic.	narasin, apolyether ionophorous antibiotic capable of acting as a transmembrane carrier of cations, has a growth inhibitory effect on acholeplasma laidlawii, permitting only 20% survival when present as 0.1 micrograms/ml in an undefined growth nutrient or fatty acid-deficient nutrient supplemented only with palmitic acid. when a. laidlawii is propagated in fatty acid-deficient nutrient supplemented with linoleic acid, however, the organisms become 40 times more sensitive to the growth inhibitory ...	1980	7407129
[blast transformation in response to plant mitogens in wistar rats infected with mycoplasma arthritidis or acholeplasma laidlawii].	the response of lymphocytes of m. arthritidis- or a. laidlawii-infected rats to pha and cona was studied. mycoplasma infection was shown to stimulate the dna synthesis in lymphocytes of the spleen and lymph nodes and to depress the responses to mitogenes one week after infection. by the same time splenocytes of a. laidlawii-infected rats were shown to only slightly proliferate in response to pha. after 4 weeks of infection the lymphocyte transformation was greatly increased in both mycoplasma- a ...	1980	7407377
adsorption, capping, and release of a complex bacteriophage by mycoplasma cells.	by electron microscopic studies, the adsorption and release of nonlytic, cytocidal mycoplasma virus mvl3, which infects acholeplasma laidlawii cells, have been examined. the mvl3 virion has a polyhedral head, collar, short tail, and tail fibers and contains linear double-stranded dna. adsorbed mvl3 virus showed a temperature-dependent clustering or capping on the mycoplasma cell membrane. during infection, a number of virus-cell membrane-related structures were observed, suggesting a general mod ...	1980	7441822
orientational order of unsaturated lipids in the membranes of acholeplasma laidlawii as observed by 2h-nmr.	oleic acid specifically deuterated at fifteen different positions along the chain, including the double bond, was biosynthetically incorporated into the membrane lipids of the microorganism acholeplasma laidlawii b. a detailed study of the dynamic conformation of these chains was carried out using deuterium nuclear magnetic resonance. the deuterium spectra fourteen different samples were recorded as a function of temperature over the range 0-41 degrees c. spectra were obtained down to -52 degree ...	1980	7407113
[stimulation of erythropoiesis in mice with mycoplasma infections].	mycoplasma arthritidis was shown earlier to induce erythropoietin-independent erythropoiesis in infected mice. this study demonstrated the increased 59fe incorporation in the mouse spleen as early as day 4 after infection with m. arthritidis. it is known that inoculation of mice with low doses of actinomycin d (act d) results in a specific suppression of erythropoiesis without impairing the endogenous erythropoietin production. in this study the mice were injected with act d (80 microgram/kg bod ...	1980	7448391
[chronic infection of acholeplasma laidlawii by a group l 1 mycoplasma virus].	mycoplasma virus mvl 51, of the group l1 of gourlay, has been shown to induce a chronic cell infection of two reference strains (1305/68 and ja 1) of acholeplasma laidlawii. titers of virus and cells remain at a fairly high level during infection, around 10(8) units/ml, with a mean ratio of approximately 1 pfu/1 cfu, as under control of a regulation mechanism. however, sudden spontaneous variations in the virus level do occur, from time to time, thus suggesting transient regulation breaks but no ...	1980	7407696
membrane composition and virus susceptibility of acholeplasma laidlawii.	the membrane composition of 11 strains of acholeplasma laidlawii, including three strains persistently infected with mycoplasmaviruses mvl51, mvl2, and mvl3, was studied and correlated with mycoplasmavirus sensitivity. membranes of the strains had similiar sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns, and all strains were inhibited by an antiserum produced against membranes from one of the strains. the amounts of integral membrane proteins solubilized by the nonionic deterg ...	1980	7410317
[stimulation of hematopoiesis in mice inoculated with mycoplasma arthritidis].	m. arthritidis is known to enhance the leukemogenic effect of rauscher leukemia virus in mice of different strains. as we have found earlier, m. arthritidis enhanced endogenous colony formation in irradiated mice. in this paper we made an attempt to establish a connection between these two phenomena. the mixed inoculation of balb/c mice with m. arthritidis and rauscher leukemia virus produced a great increase in the number of endogenous colonies as compared with the effect of mycoplasmas alone, ...	1980	7415681
detection of mycoplasmal contaminants in sera.		1981	7275992
isolation and characterization of mycoplasma and acholeplasma from apparently healthy and diseased (infectious sinusitis) turkeys.	investigation of 136 turkeys (24 manifesting infra-orbital sinusitis, 112 apparently healthy) resulted in isolation of 79 strains of mycoplasma and 4 of acholeplasma. by the disc growth inhibition test with 16 reference antisera of avian serogroups, 55 strains were identified serologically and 28 remained unidentified. thirteen strains of mycoplasma gallisepticum, 1 of m. meleagridis, and 2 of acholeplasma laidlawii were isolated from turkey sinusitis whereas serogroups c (2), d (19), f (8), m. ...	1981	7278710
isolation of mycoplasma from a buffalo (bubalus bubalis) with mastitis.		1981	7199239
reversed cubic phase with membrane glucolipids from acholeplasma laidlawii. 1h, 2h, and diffusion nuclear magnetic resonance measurements.	monoglucosyl diglyceride and diglucosyl diglyceride are the dominant lipids of the acholeplasma laidlawii membrane. diglucosyl diglyceride forms a lamellar liquid crystalline phase with water while monoglucosyl diglyceride forms a reversed hexagonal phase. depending on the amounts of unsaturated acyl chains of the lipids, a mixture of monoglucosyl diglyceride and diglucosyl diglyceride forms lamellar or reversed cubic phases at physiological temperatures. a high degree of cis unsaturation favors ...	1981	7213607
lipid and protein membrane components associated with cholesterol uptake by mycoplasmas.	membranes of mycoplasma species take up 2--4 times more exogenous cholesterol than membranes of acholeplasma species. to test whether the lower cholesterol uptake capacity of acholeplasma is due to the high glycolipid content of their membranes, the phospholipids of acholeplasma laidlawii and mycoplasma capricolum membranes were hydrolyzed by phospholipase a2. digestion removed about 30% of the polar lipids of a. laidlawii, leaving the glycolipids and phospholglycolipids intact, and about 70% of ...	1981	7213725
purification and characterization of nadh oxidase from membranes of acholeplasma laidlawii, a copper-containing iron-sulfur flavoprotein.	1. nadh oxidase was extracted from the membranes of acholeplasma laidlawii with buffer containing 3% triton x-100 and subsequently purified by several chromatographic steps. the final preparation was essentially homogeneous as judged by gel electrophoresis under nondenaturing conditions. 2. the enzyme appears to be a copper-containing iron-sulfur flavoprotein (fmn:cu:fe:labile s = 1:1:6:6). the enzyme, containing a high fraction of hydrophobic amino acids, is composed of three subunits of molecu ...	1981	7318830
release of a group 1 mycoplasma virus from acholeplasma laidlawii after treatment with mitomycin c.	a rod-shaped group 1 mycoplasma virus was released from acholeplasma laidlawii strain ja2 after treatment with 2.5 mug of mitomycin c per ml. similar treatment of a. laidlawii strain bju failed to stimulate release of any pfu.	1981	6793734
interactions of acholeplasma laidlawii cells with mouse spleen lymphocytes.	interaction between acholeplasma laidlawii cells labelled with oleic acid and mouse spleen lymphocytes depended on the time of incubation, on the temperature and on the quantitative ratio between both cells. uncouplers and edta did not influence the intensity of attachment. the resistance of binding to cytochalasin b amd glutaraldehyde as well as localization of a. laidlawii antigens on the lymphocyte surface and experiments with [14c] uridine-labelled mycoplasmas are an evidence against the par ...	1981	6797154
protective efficacy of mycoplasma pneumoniae polysaccharides.	mycoplasma pneumoniae accounts for up to 35% of all pneumonias at times when influenza epidemics are not prevalent. therefore, considerable efforts have been directed towards the developmemt of a vaccine against mycoplasmal respiratory tract disease. the protective efficacy of inactivated m. pneumoniae vaccine, prepared so far, did not exceed 67%. this incomplete protective effect may have been due to insufficient immunogenicity and/or to failure of vaccines administered by the parenteral route ...	1981	6793538
a note on positive bactec readings produced by mycoplasma.		1981	7024236
eliminating mycoplasmas from contaminated cell cultures.	mycoplasmas are bothersome contaminants in cell cultures. cells derived from various sources are subject to contamination and although many procedures have been suggested to eliminate the contaminating mycoplasmas, there is no simple, rapid and effective method for eliminating them. we have devised a method for the selective killing of mycoplasmas based on the differences between the nucleic acid metabolism of mycoplasmas and that of tissue culture cells. whereas the nutritional requirements of ...	1981	6169683
chronic exposure to inhaled anesthetics increases cholesterol content in acholeplasma laidlawii.	acholeplasma laidlawii cells were grown in cholesterol-enriched medium and exposed continuously to either air (control), 4.0 vol.% halothane in air at 1 atm pressure (4% atm halothane), or 80% cyclopropane in oxygen for 24 h at 37 degrees c. cells grown in the presence of 4% atm halothane or 80% cyclopropane had approximately twice as much membrane cholesterol content/mg protein as the control cells. cells grown in an anesthetic environment also tended to have a higher membrane cholesterol/phosp ...	1981	6274406
[biochemical and serologic study of acholeplasmae isolated from monkeys].	biochemical and serological properties of mycoplasmas isolated from the blood, feces and parenchymatous organs of monkeys have been studied to determine their species. it was established that the isolated strains belong to the family acholeplasmatoceae. the study of their biochemical properties in different tests has revealed the presence of 5 biochemically heterogeneous groups. their serological properties suggest that 13 out of 45 strains are identical to the reference strain of a. laidlawii a ...	1981	6787821
altered surface structure of acholeplasma laidlawii induced by mycoplasmavirus l3 infection.		1981	6456906
protein-lipid interactions in biological and model membrane systems. deuterium nmr of acholeplasma laidlawii b, escherichia coli, and cytochrome oxidase systems containing specifically deuterated lipids.		1981	6256386
cholesterol transfer from normal and atherogenic low density lipoproteins to mycoplasma membranes.	the purpose of this study was to determine whether the free cholesterol of hypercholesterolemic low density lipoprotein from cholesterol-fed nonhuman primates has a greater potential for surface transfer to cell membranes than does the free cholesterol of normal low density lipoprotein. the low density lipoproteins were isolated from normal and hypercholesterolemic rhesus and cynomolgus monkeys, incubated with membranes from acholeplasma laidlawii, a mycoplasma species devoid of cholesterol in i ...	1981	7295188
protein composition and extractability of lipid-modified membranes from acholeplasma laidlawii.	membranes from acholeplasma laidlawii have been extracted with neutral detergents, which solubilize the proteins and lipids selectively, or with sodium deoxycholate, which gives an almost total solubilization. the amounts of individual proteins present in the detergent extracts of membranes with induced variations in lipid compositions were determined by crossed immunoelectrophoresis. extraction with the neutral detergent tween 20 showed that ionic lipids and the glucolipid diglucosyl diglycerid ...	1981	7306495
bovine genital mycoplasmosis.	infection, lesions and clinical significance of acheloplasmas, mycoplasma bovis and mycoplasma bovigenitalium in genital disease of cattle are described. a more detailed account is given of ureaplasma infections. acute and chronic forms of granular vulvitis in both field and experimental disease are described as well as the role of the organism in abortion. recovery rates of ureaplasma and mycoplasma from semen and preputial washings in bulls are outlined and their significance in disease is dis ...	1981	7337908
adenylate energy charge in acholeplasma laidlawii.	adenosine 5'-triphosphate, adenosine 5'-diphosphate, and adenosine 5'-monophosphate were produced by acholeplasma laidlawii b-pg9 growing in modified edward medium. the adenylate energy charge was calculated to be 0.84 +/- 0.07 and ranged from 0.91 to 0.78 during exponential growth (12 to 24 h). during exponential growth, a. laidlawii contained, at 17.5 h, 2.3 x 10(-17) mol of adenosine 5'-triphosphate per colony-forming unit and, at 16 h, 27.3 nmol of adenosine 5'-triphosphate per mg (dry weigh ...	1981	7240083
respiration-associated components of mollicutes.	no cytochrome pigments were detected by difference (reduced minus oxidized) spectroscopy at liquid nitrogen temperature in whole-cell preparations or membrane fractions of acholeplasma axanthum s273, acholeplasma equifetale n93, acholeplasma granularum bts39, acholeplasma laidlawii b-pg9, acholeplasma modicum pg-49, acholeplasma oculi 19l, mycoplasma arginini g230, mycoplasma arthritidis 07, mycoplasma pneumoniae fh, and mycoplasma pulmonis jb. all ten mollicutes species examined contained iron ...	1981	7240087
effects of anesthetics on water permeability and lipid metabolism in acholeplasma laidlawii membranes.	the addition of tetracaine and diethyl ether to acholeplasma laidlawii at concentrations commonly used for local anesthesia did not affect water permeability over the cell membrane, as measured by a pulsed magnetic field gradient nmr method. however, a. laidlawii changed its membrane lipid composition upon treatment with these anesthetics. both tetracaine and diethyl ether addition resulted in a decrease in the molar ratio between the major membrane glucolipids, monoglucosyldiacylglycerol and di ...	1981	7260084
mycoplasma-virus contacts, budding and scars remaining in the membranes of acholeplasma laidlawii and its virus.	various stages of virus and mycoplasma budding indicated that both virus and, most probably some mycoplasma progeny developed by budding. besides this alternative, binary fission was the mode of mycoplasma reproduction. mycoplasma-virus and mycoplasma-mycoplasma connections by stems were observed. circular scars, 40-80 nm in diameter, often in groups, were left in the membrane of mycoplasmas by the budding bodies. cytoplasmic structures seen in cross-fraction are presented. a relatively small nu ...	1981	7286853
first observation of amino acid side chain dynamics in membrane proteins using high field deuterium nuclear magnetic resonance spectroscopy.	we have obtained the first deuterium nmr spectra of an individual membrane protein, bacteriorhodopsin in the purple membrane of halobacterium halobium r1. biosynthetic isotopic enrichment with [gamma-2h6]valine and high field fourier transform operation permitted rapid data acquisition on intact membranes, including measurement of relaxation times. at some temperatures high quality spectra could be obtained in less than 1 s. [u-14c]valine tracer studies indicate that less than or equal to 2% of ...	1981	7217074
the effect of cholesterol on the phase structure of glucolipids from acholeplasma laidlawii membranes.	1. the packing properties in lipid mixtures containing cholesterol and membrane glucolipids from acholeplasma laidlawii are modified by varying the amounts of cholesterol, diacylmonoglucosylglycerol and diacyldiglucosylglycerol in the mixtures as well as the temperature and the degree of acyl chain unsaturation. these changes affect both the proportions of different lipids having dissimilar molecular geometries and the geometry of the lipid molecules themselves. 2. all mixtures containing glucol ...	1981	7250125
studies on acholeplasma laidlawii grown on branched-chain fatty acids.		1981	7259182
cytoplasmic helical structure associated with acholeplasma laidlawii.	a distinct spiral protein structure was found in three species of acholeplasma, but was not found in the mycoplasma species studied. the spirals, which are 14 nm in width and of variable length from 50 to 300 nm, are formed by a helical arrangement of 7-nm subunits. a rosette-like structure 45 nm in diameter also composed of 7-nm subunits was found in close association with the spirals and may be a taut in vivo form of the spiral. the electrophoretic profile in sodium dodecyl sulfate-polyacrylam ...	1981	7263616
distribution of ureaplasmas in the urogenital tract of ewes.		1981	7344258
membrane structures of acholeplasma laidlawii and its virus.	the main types of ultrastructures found in the freeze-fracture faces of acholeplasma laidlawii s 2 and its virus mv-lg-l 172 were (1) particles 7-19 nm in diameter, mostly located in the convex cytoplasmic fracture faces. (2) small bulges or aggregates, 13-25 nm in diameter, which occupied only limited areas of both inner and outer fracture faces of some mycoplasmas, (3) numerous tiny grains and/or spikes 2-6 nm in diameter, protruding from a finely structured background, especially in the outer ...	1981	7286852
[simultaneous isolation of infected and non-infected clones of mycoplasmas from plaques obtained on acholeplasma laidlawii lawns with a virus of group l1 of gourlay].		1982	7124157
lipid-phase transition of phosphatidylglycerol in acholeplasma laidlawii membranes studied with phospholipase a2.	phospholipase a2 was applied to follow the lipid phase transition of phosphatidylglycerol in the membrane of acholeplasma laidlawii. the conclusions were identical with those obtained with physicochemical techniques. in addition, it was shown that phosphatidylglycerol undergoes the lipid phase transition in the same temperature range as the bulk of the membrane lipid; phase segregation between various molecular species of phosphatidylglycerol occurs; exchange of this phospholipid between rigid a ...	1982	6889758
receptor sites for mycoplasmal viruses on acholeplasma laidlawii.	all three groups of mycoplasmal viruses tested, mvl1, mvl2, and mvl3, were inactivated by both membranes and lipoglycan from acholeplasma laidlawii strain ja1. the interaction was specific for components of a. laidlawii since no inactivation occurred with either membrane or lipoglycan from acholeplasma oculi. adsorption of virus was proved by the demonstration of radiolabeled virus-lipoglycan or virus-membrane particles that were separable in density gradients from either component alone. recept ...	1982	6289406
molecular properties of membrane lipids and activity of a membrane adenosine triphosphatase from acholeplasma laidlawii b.	the effects of membrane lipid fluidity and phase state on enzyme activity were evaluated by careful analysis of arrhenius plots of the na+, mg2+-dependent adenosine triphosphatase (referred to hereafter as atpase) from acholeplasma laidlawii b membranes and differential thermal analysis of the membrane lipid phase transitions. arrhenius plots of the atpase activity in membranes containing only liquid-crystalline lipids are gently curved and have the same form regardless of the membrane fatty liv ...	1982	6214837
cholesterol and phospholipid uptake by mycoplasmas.	mycoplasma offer several unique advantages for investigating the mechanism controlling transfer and uptake of exogenous cholesterol and phospholipids by biomembranes, as their plasma membrane interacts directly with exogenous lipid donors and their endogenous lipid synthesis is restricted. growing cells of five species of mycoplasma were found to take up significant quantities of phosphatidylcholine and sphingomyelin as well as free and esterified cholesterol. in contrast, growing cells of three ...	1982	6289408
molecular organization and selective solubilization of lipids and proteins in the envelope of mycoplasmal virus l2.	the composition and molecular organization of mycoplasmal virus l2 (mvl2) were studied and compared with those of the cell membrane of the host, acholeplasma laidlawii strain ja1. the virus contained 0.2-0.25 mumol of polar lipids per mg of viral protein. the lipid species of the mvl2 were the same as those of the host cells. nevertheless, the proportions between the various polar lipids were different, with a much lower content of phosphatidylglycerol in the viral lipids. despite these quantita ...	1982	6289409
elucidation of the antigenic architecture of the acholeplasma laidlawii cell membrane by immunoabsorption in combination with crossed immunoelectrophoresis.	immunoabsorption in combination with crossed immunoelectrophoresis was used for elucidation of the antigenic architecture of the acholeplasma laidlawii cell membrane. when cells were grown in a medium containing cholesterol and unsaturated fatty acids, the cell membranes became fragile. membrane proteins or membrane fragments, which under some conditions seemed to be enriched in specific proteins (especially protein t2), were released into the growth medium. therefore, most of the experiments we ...	1982	6181548
[proteins of bacterial membranes. h+-adenosinetriphosphatase from acholeplasma laidlawii cells].	the cytoplasmic membrane of micoplasmic cells, in particular of a. laidlawii cells, contains a proton-carrier mg2+ -activated atpase. a whole h+ -atpase complex (f0-f1) was isolated from these cells and characterized. the isolation procedure included solubilization of the enzyme with triton x-100 followed by ion-exchange chromatography on deae-cellulose and gel filtration on sepharose 6b. the enzyme was inhibited by dicyclohexylcarbodiimide (10(-4) m). the km value for atp hydrolysis and ki for ...	1982	6123348
effects of pressure and pressure antagonists on the growth and membrane-bound atp-ase of acholeplasma laidlawii b.	1. arrhenius plots of the membrane-bound atp-ase were constructed at pressures of 300, 600 and 900 atm. pressure shifts the plots to higher temperatures with an increase in slope. 2. these data are partially consistent with a kinetic model in which a phase transition in the lipids associated with the atp-ase determines the activity of the enzyme. they are also consistent with a model in which the non-linear arrhenius plot is caused by the low temperature inactivation of the enzyme, upon which pr ...	1982	6125309
cytosine methylation of the sequence gatc in a mycoplasma.	mycoplasma virus l2 is subject to host-specific restriction and modification in acholeplasma laidlawii strains ja1 and k2. we have examined the dnas from both host cells and viruses propagated on these strains with respect to susceptibility to cleavage by restriction endonucleases and for dna base modifications. we show that, in strain k2 and l2 virus grown on k2 cells, cytosine in the sequence gatc is methylated to 5-methylcytosine and, although strain k2 and l2 viruses grown on k2 contain n6-m ...	1982	6286600
ribosomal rna genes in mycoplasma.	using southern blotting analysis with labelled mycoplasmal ribosomal rna as probe, two fragments (1 kb and 5 kb) were detected in an ecor i digest of mycoplasma capricolum dna. this analysis revealed that the 5 kb fragment carries both 16s rrna sequences and the entire 23s rrna gene of this mycoplasma. the 1 kb fragment contains 16s rrna sequences only. the 5 kb ecor i fragment has been cloned and used to characterize the structure of rrna cistrons in various mycoplasma strains. these experiment ...	1982	6289267
serological investigation of horse sera for antibodies against mycoplasmas and acholeplasmas.	sera from horses with respiratory disease (rd) have been investigated using the complement fixation test, indirect hemagglutination test, enzyme immune assay, and the metabolic inhibition test, and sera from mares after abortion, using the complement fixation test, indirect hemagglutination test and enzyme immune assay, for antibodies against mycoplasma equirhinis, m subdolum, m. equigenitalium, m. pulmonis, m. felis, acholeplasma laidlawii, a. hippikon and a. equifetale. antibodies were found a ...	1982	7112894
emmy klieneberger-nobel award lecture: the protein fingerprints of mycoplasmas.	the proteins of 91 strains of mycoplasma from 19 established species and three groups of uncertain taxonomic position were separated by two-dimensional polyacrylamide gel electrophoresis. considerable variations in protein patterns were found among strains from the same species or subspecies; the percentage of matching spots (% of congruence) ranged from 42%-100%, but many proteins were strongly conserved in all strains of a given species. maps of these conserved proteins could be used to identi ...	1982	6750757
[equine mycoplasma typing using the direct immunofluorescence technic].		1982	6764691
isolation of acholeplasma laidlawii from a giraffe (giraffa camelopardalis rothschildi) and a mouflon (ovis musimon).		1982	7064318
lateral mobility of membrane-bound antibodies on the surface of acholeplasma laidlawii: evidence for virus-induced cell fusion in a procaryote.	dynamic processes on the membrane of the procaryotic cell acholeplasma laidlawii have been studied by means of immunoelectron microscopy. colloidal gold-labeled anti-a. laidlawii antibodies were used as electron-dense markers. this method allowed the demonstration of temperature-dependent lateral mobility of membrane-bound immunoglobulins. by using two different sizes of gold grains to differentiate cells from two different cell populations, virus-induced fusion of procaryotic cells could be sho ...	1982	7118831
prevalence of mycoplasma and chlamydia in the nasal flora of dairy calves.	nasal swabs from dairy calves in 20 selected herds were collected once in each of three sampling periods in one year and cultured for mycoplasmas and chlamydiae. seventy-seven of 411 calves (19%) and 16 of 20 herds (80%) were positive for mycoplasmas at least once throughout the year, and all of 378 calves sampled from the 20 herds were negative for chlamydiae. thirty-one percent of the isolates were mycoplasma bovirhinis; other species isolated less frequently were mycoplasma bovis, mycoplasma ...	1982	7179720
monoclonal antibodies specific for cell culture mycoplasmas.	mycoplasma infection of cell cultures is still a major problem in some laboratories. although several methods can be used for their detection, identification is normally by serological procedures. as no commercial source for the necessary antibodies is available we have prepared monoclonal antibodies to the five mycoplasma species that account for the majority of cell culture infections. these antibodies have been characterized by the growth inhibition test (git), immunofluorescence, and enzyme ...	1982	6811415
isolation and identification of mycoplasmas from the respiratory tract of the white leghorn chicken in the sudan.		1982	7093655
isolation and preliminary characterisation of mycoplasmavirus 20-p.	a mycoplasmavirus, mv 20-p, was isolated from the fastidious, slow-growing human mycoplasma 20-p, previously identified by the growth inhibition test as mycoplasma hominis type 2. its broth culture was ultracentrifuged into 35% saccharose, the pellet was resuspensed in buffer, and the suspension was dropped onto laws of the virus indicator acholeplasma laidlawii bcl-13. the virus was washed off the plaque areas by buffer. mv 20-p appeared in electron microscopy as spherical, enveloped particles ...	1982	7098542
isolation of acholeplasmas and a mycoplasma from vegetables.	the isolation of mollicutes from food has not been reported. to isolate mollicutes in the presence of high levels of unwanted bacteria, we first incubated fresh vegetables in liquid culture media containing lysozyme, ampicillin, and thallous acetate. culture fluids were than separated from the vegetable samples, subjected to one freeze-thaw cycle, and passed through a filter of 0.4-micron porosity. filtered samples were cultured in sp4 medium and in a conventional medium containing horse serum. ...	1982	7036899
adsorption of the tailed mycoplasma virus l3 to cell membranes.	the adsorption properties of the tailed bacteriophage l3 to acholeplasma laidlawii cells were studied. adsorption followed a biphasic curve. reversibility and virus heterogeneity were not sufficient to explain the break in the adsorption curve. binding studies showed that each colony-forming unit could bind about 350 virions. the electrostatic nature of l3 adsorption was indicated by the effect of cations, ph, and temperature on the adsorption rate constant. l3 adsorption appeared to have a requ ...	1982	7042999
the use of differential scanning calorimetry and differential thermal analysis in studies of model and biological membranes.	differential scanning calorimetry (dsc), and to a lesser extent differential thermal analysis (dta), are powerful yet relatively rapid and inexpensive thermodynamic techniques for studying the thermotropic phase behavior of lipids in model and biological membranes, without the introduction of exogenous probe molecules. in this review the principles as well as the scope and limitations of dsc and dta are discussed first. the application of these techniques to the study of the thermotropic phase b ...	1982	7046969
immunological and functional activity of spleen lymphocytes from mice infected by acholeplasma laidlawii cells and rauscher virus.	the duration of acholeplasma laidlawii antigen persistence in mice, resistant to rausher leukemia virus, after infection with both a. laidlawii cells and rausher virus has been studied. the antigen persistence was accompanied by marked depression of immune response which was especially severe in case of mixed acholeplasmavirus infection. such immunosuppression and observed infiltration of the spleen with immature leukemic cells can be regarded as a preleukosis. immunosuppression was accompanied ...	1982	7048811
comparison of ciliostasis by mycoplasmas in mouse and chicken tracheal organ cultures.	the cilia-stopping effect of mycoplasmas of human and various animal origin in mouse and chicken tracheal organ cultures was studied. from the results in mouse tracheal organ cultures, the mycoplasma strains tested were divided into three groups: mycoplasma pulmonis m53, m pulmonis jb, m. pulmonis ok, m. mycoides subsp. mycoides pgl and m. gallisepticum s6 showed a strong cilia-stopping effect; m. pulmonis pg22, m. mycoides subsp. capri pg3, m. meleagridis 19729, m. neurolyticum type a and m. ar ...	1982	7087799
effects of cholesterol on the orientational order of unsaturated lipids in the membranes of acholeplasma laidlawii. a 2h-nmr study.	we have investigated by 2h-nmr the effects of the incorporation of cholesterol on the orientational order of unsaturated lipid acyl chains in the membranes of acholeplasma laidlawii b. this is the only 2h-nmr study to date of the influence of cholesterol in a biological membrane using specifically labelled fatty acids. we observed the characteristic condensing effect of cholesterol on the lipid acyl chain order in the liquid crystalline phase. in terms of the percentage increase in the quadrupol ...	1982	7093275
preferential uptake of lipids by mycoplasma membranes from human plasma low-density lipoproteins.	the binding and transfer of low-density lipoprotein (ldl) constituents to mycoplasma membranes were examined. mycoplasma capricolum was found to bind more 125i-labeled ldl than acholeplasma laidlawii. free and esterified cholesterol uptake was 3-4 times higher in m. capricolum than in a. laidlawii. cholesterol transfer to the membranes of both organisms far exceeded the amounts of cholesterol expected according to ldl protein found associated with the membranes. trypsin digestion of the membrane ...	1982	7150569
properties of the nucleases of mollicutes.	extracts of the mollicutes acholeplasma equifetale, acholeplasma laidlawii b, mycoplasma arthritidis. mycoplasma pulmonis, and mycoplasma pneumoniae had dnase and endonuclease activity. a. laidlawii b had at least two peaks of dnase activity in sucrose gradients with sedimentation coefficients of 3.1s and 4.3s. these fractions also had endonuclease activity with different substrate specificities. a. laidlawii b may have more than two peaks of endonuclease activity in sucrose gradients.	1982	6811565
[proteins of bacterial membranes. nadh-dehydrogenase from the cells of acholeplasma laidlawii].	using ion-exchange chromatography on deae-cellulose and gel filtration, a purified nadh-dehydrogenase was prepared from cell membranes of a. laidlawii. the enzyme specific activity exceeds the activity of the membrane preparation 45-fold. the enzyme is thermolabile and sensitive to lecithine. electrophoresis of the enzyme preparation in the presence of na-ds resulted in two proteins with mr of 65 000 and 72 000. specific staining of the gels with triphenyltetrasolium chloride in the presence of ...	1982	7150675
comparison of the ultrastructural aspects of acholeplasma laidlawii grown in liquid and solid media.		1982	7159213
replication of mycoplasma virus l51. vii. effect of chloramphenicol on the synthesis of dna replicative intermediates.	chloramphenicol affects several steps in the dna replication of mycoplasma virus l51, a noncytocidal, naked, bullet-shaped virion containing circular single-stranded (ss) dna of 1.5 x 10(6) daltons (4.5 kilobases). in the presence of chloramphenicol, adsorption was normal and parental ss dna was converted to double-stranded replicative forms (rf), but subsequent rf leads to rf replication was inhibited. chloramphenicol added late in infection, when most viral nascent dna is in progeny ss molecul ...	1982	7176020
effect of molecular weight of polyethylene glycols on inactivation of mycoplasma pulmonis and acholeplasma laidlawii a.		1982	7186082
a 2h-nmr study of acholeplasma laidlawii membranes highly enriched in myristic acid.	myristic acid specifically deuterated at several positions along the acyl chain was biosynthetically incorporated into the membrane lipids of acholeplasma laidlawii b to the level of greater than or equal to 90%. 2h-nmr was used to study the molecular order and lipid phase composition of the membranes as a function of temperature. isolated membranes and intact cells give rise to similar 2h spectra. below 25 degrees c the spectra exhibit a broad gel phase component which at 0 degrees c reaches th ...	1982	7104342
identification of iron- and phosphorus-containing antigens of the acholeplasma laidlawii cell membrane.		1982	7106296
virus capping on mycoplasma cells and its effect on membrane structure.	the capping of mycoplasmavirus l3 on the surface of acholeplasma laidlawii was investigated. in electron microscope studies we observed a reduced capping after treatment of the host cell with energy-blocking agents. other drugs inhibiting ligand capping on eucariotic cells had no effect. changes in membrane structure after virus adsorption were observed spectroscopically using the excimer fluorescence technique. the results are interpreted in terms of a lipid-protein phase separation in connecti ...	1982	7115700
active diffusion of adsorbed mycoplasmal virus l3 on acholeplasma laidlawii cell membranes.		1982	7123047
lipid phase structure in the regulation of lipid composition in acholeplasma laidlawii membranes.	in acholeplasma laidlawii membranes the ratio between the dominating lipids, monoglucosyldiglyceride (mgdg) and diglucosyldiglyceride (dgdg), depends on temperature, configuration of incorporated fatty acids, and membrane cholesterol content, which affect the molecular geometry of the lipids. mgdg and dgdg have wedge- and rod-like molecular shapes, respectively, that are modifiable. the packing constraints of lipids in amphiphilic aggregates, i.e., the area of the hydrocarbon-water interface and ...	1982	7123057
the electrochemical potential across mycoplasmal membranes.	the electrochemical proton gradient across mycoplasmal membranes was studied. the transmembrane proton-motive potential, delta p, is composed of two parameters, a transmembrane electric potential difference, delta psi, and a transmembrane proton gradient, delta ph, according to the formula delta p = delta psi -(a x delta ph). membrane potentials were determined with use of potential-sensitive cyanine dyes. the delta psi for both mycoplasma mycoides subspecies capri and mycoplasma gallisepticum w ...	1982	7123058
membrane lipid fluidity and physical state and the activity of the na, mg-atpase of acholeplasma laidlawii b.		1982	19431488
origins of the mycoplasmas: sterol-nonrequiring mycoplasmas evolved from streptococci.	we report the establishment of a phylogenetic relationship between the sterol-nonrequiring mycoplasmas (acholeplasma species) and streptococci. three specific antisera prepared against purified streptococcus faecalis fructose diphosphate aldolase and glyceraldehyde-3-phosphate dehydrogenase and pediococcus cerevisiae glyceraldehyde-3-phosphate dehydrogenase were used for comparative enzyme immunological studies; the ouchterlony double-diffusion technique and the quantitative microcomplement fixa ...	1982	6176574
characterization of the enveloped plasmavirus mvl2 after propagation on three acholeplasma laidlawii hosts.	plasmavirus mvl2 was propagated on three acholeplasma laidlawii strains, ja1, s2, or bc1-13. previously reported host-controlled modification (hcm) of mvl2, as reflected by changes in plating efficiency, was observed. adsorption rates and one-step growth curves varied according to host used. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the three mvl2 populations revealed differences in polypeptide profiles.	1983	6830442
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.	1983	6679154
membrane isolation alters the gel to liquid crystal transition of acholeplasma laidlawii b.	the gel to liquid crystal phase transition of membrane lipids of live acholeplasma laidlawii b was monitored by infrared spectroscopy. it was found that, while isolated membranes are predominantly in the gel phase at the growth temperature, the live cell membranes contain a large liquid crystal phase component.	1983	6849129
polyethylene glycol-dependent transfection of acholeplasma laidlawii with mycoplasma virus l2 dna.	phenol-extracted dna from mycoplasma virus l2 was able to transfect acholeplasma laidlawii in the presence of polyethylene glycol. transfection was sensitive to dnase and was most efficient with 36% (wt/vol) polyethylene glycol 8000 and cells in logarithmic growth. virus production by the transfected cells was similar to that of the cells infected by intact virus. l2 dna transfected a. laidlawii with a single-hit dose-response curve, reaching saturation at high dna concentrations. optimum transf ...	1983	6874642
cell culture media: contamination at flow labs.		1983	6888532
the biosynthetic incorporation of diacetylenic fatty acids into the biomembranes of acholeplasma laidlawii a cells and polymerisation of the biomembranes by irradiation with ultraviolet light.	acholeplasma laidlawii a has been grown in media containing synthetic, long chain c20- and c23-fatty acids possessing a diacetylene group in their acyl chains. growth on the c23 diacetylenic acid was poor but was good on the c20 acid. biosynthetic incorporation of the fatty acids occurs; as much as 90% of the membrane lipid fatty acyl chains consisting of the c20-diacetylenic fatty acid, the remainder being shorter chain, saturated fatty acids. the thermal phase transition of this biomembrane ha ...	1983	6838876
radiation studies of acholeplasma laidlawii: the role of membrane composition.	acholeplasma laidlawii, a mycoplasma, is unable to synthesize unsaturated fatty acids but it will incorporate them into its plasma membrane if they are supplied exogeneously. thus the fatty acid composition of the cell membrane can be defined by growing the organism in media containing specific fatty acids. we obtained cells with predominantly one type of unsaturated fatty acid (either oleic, linoleic or linolenic acid) or cells with only saturated fatty acid in the cell membrane. the cells were ...	1983	6605325
integration and lysogeny by an enveloped mycoplasma virus.	the 11.8 kilobase pair (7.8 x 10(6) mol. wt.) genome of mycoplasma virus l2 in lysogenic acholeplasma laidlawii cells was examined. for this study, dnas were analysed by agarose gel electrophoresis and viral dna sequences identified by dna-dna hybridization. l2 dna was found to be integrated into the lysogenic host cell chromosome at a unique site in both viral and cellular dna. the viral dna site was roughly mapped and the approximate time of integration during the l2 non-cytocidal infectious c ...	1983	6308135
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 ...	1983	6138096
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 ...	1983	6187792
[the pathogenic properties of acholeplasma in experiments in guinea pigs].		1983	6400777
extraction of membrane lipids during fixation, dehydration and embedding of acholeplasma laidlawii-cells for electron microscopy.		1983	6405040
fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in acholeplasma laidlawii b membranes. effects of methyl-branch substitution and of trans unsaturation upon membrane acyl-chain orientational order.	the hydrocarbon-chain orientational order parameters of membranes of acholeplasma laidlawii b enriched with straight-chain saturated, methyl iso-branched, methyl anteiso-branched, or trans-unsaturated fatty acids have been determined via fluorine-19 nuclear magnetic resonance spectroscopy (19f nmr). a theoretical description of the 19f nmr spectral line shape is presented that permits the determination of the orientational order parameters associated with specifically monofluorinated palmitic ac ...	1983	6652059
[interaction of acholeplasma laidlawii and mycoplasma arthritidis with the lymphocytes of mice of different strains].	the interaction of mycoplasmas and mouse lymphocytes has been studied by the microbiological and electron-microscopic methods. the experiments have shown that a. laidlawii and m. arthritidis are adsorbed on lymphocytes and thymocytes of (c57bl6 x a/he)f1, balb and c57bl mice after 15 minutes of their joint incubation at 37 degrees c, 1 hour later adsorption reaches its maximum intensity and after further prolongation of the time of incubation the number of adsorbed microbial cells remains unchan ...	1983	6659765
[mycoplasma mastitis of cattle. 11. histological udder findings after experimental infection with mycoplasma bovigenitalium and acholeplasma laidlawii].		1983	6615133
transport activity of mouse spleen lymphocytes after their interaction in vitro with acholeplasma laidlawii cells.	transport of two non-metabolized carbohydrates (3-o-methyl-d-glucose, 3-o-mg, and 2-deoxy-d-glucose, 2-dg) into mouse spleen lymphocytes after their interaction with acholeplasma laidlawii cells has been studied. incubation of a. laidlawii cells and particularly the liposomes prepared from a. laidlawii membrane lipids enhances the rates of the both carbohydrates transport. this treatment resulted in increasing of the vmax values of 3-o-mg and 2-dg without changing the km values. this stimulation ...	1983	6659737
mycoplasmal infection of insect cell cultures.	twenty-five cell cultures of three insect orders from eight laboratories were tested for mycoplasmal infection. acholeplasma laidlawii was detected in one culture, an incidence of 4.0%. a. laidlawii, mycoplasma orale, m. arginini, but not m. hyorhinis, could establish infections of drosophila dm-1 cell cultures at 25 degrees c. in prospective studies, drosophila dm-1 cultures were intentionally infected with broth-propagated a. laidlawii and m. hyorhinis. m. hyorhinis did not grow and was elimin ...	1983	6413389
intraspecies genetic relatedness among strains of acholeplasma laidlawii and of acholeplasma axanthum by nucleic acid hybridization.	this study compares the intraspecies genetic relatedness among strains of two established species of acholeplasma. radiolabelled dna probes were prepared from three strains of acholeplasma laidlawii and two strains of acholeplasma axanthum, by using the nick translation method. the labelled dna probes of these two strains were hybridized to an excess of unlabelled dna from 12 strains of acholeplasma laidlawii and from six strains of acholeplasma axanthum, respectively. nucleic acid hybridization ...	1983	6631407
interspecies and intraspecies dna homology among established species of acholeplasma: a review.	radiolabeled dna probes prepared in vitro by the nick translation method were used to determine the nucleotide sequence homology among the eight established and one unclassified species of acholeplasma. very little dna homology (2 to 21 percent) was found among these nine distinct species and the heteroduplexes showed at least 15 percent mismatching as determined by thermal elution endpoints. the data obtained by hybridization analyses paralleled the results obtained by the growth inhibition and ...	1983	6433583
binding of mvl-2 virus to a. laidlawii cells.	binding of mvl-2 virus, whose envelope lipids were radioactively labeled, to a. laidlawii ja1 cells was determined and characterized. the binding followed first-order kinetics and was temperature-dependent. all mvl-2 particles were capable of binding to a. laidlawii cells. at least 75 percent of radioactive mvl-2 bound represented specific binding which was markedly inhibited by edta. virus infectivity was not essential for binding as inactivation of the virus by ultraviolet irradiation did not ...	1983	6433585
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 ...	1983	6685661
uracil phosphoribosyltransferase from acholeplasma laidlawii: partial purification and kinetic properties.	uracil phosphoribosyltransferase was purified 34-fold from sonicated extracts of acholeplasma laidlawii by ammonium sulfate precipitation, binding to deae-sephadex, sephadex g-200 chromatography, and hydroxylapatite chromatography. the molecular weight of the enzyme by gel filtration was approximately 80,000. the ph optimum for phosphoribosylation was around 7.5, and the optimum mgcl2 concentration was 5 mm. initial velocity studies were conducted over a wide range of both uracil and 5-phosphori ...	1983	6619094
[mycoplasma mastitis of cattle. 10. test of mycoplasma bovis, mycoplasma bovigenitalium and acholeplasma laidlawii for udder pathogenicity].		1983	6615132
synthesis of adenylate nucleotides by mollicutes (mycoplasmas).	cultures of the mollicutes (mycoplasma) acholeplasma laidlawii b, acholeplasma morum, mycoplasma bovis, mycoplasma arginini, mycoplasma fermentans and mycoplasma gallisepticum, representing four metabolic groups, were sampled at intervals over a 40 to 50 h period and assayed for the numbers of c.f.u., changes in ph and glucose concentration, and concentrations of atp, adp, amp, lactate and pyruvate. the adenylate energy charge (eca), the mean generation time, and the number of nmol of atp (mg dr ...	1983	6655457