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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 ...19827098542
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 ...19827104342
identification of iron- and phosphorus-containing antigens of the acholeplasma laidlawii cell membrane. 19827106296
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 ...19827112894
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 ...19827115700
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 ...19827118831
active diffusion of adsorbed mycoplasmal virus l3 on acholeplasma laidlawii cell membranes. 19827123047
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 ...19827123057
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 ...19827123058
[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]. 19827124157
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 ...19827150569
[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 ...19827150675
comparison of the ultrastructural aspects of acholeplasma laidlawii grown in liquid and solid media. 19827159213
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 ...19827176020
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 ...19827179720
effect of molecular weight of polyethylene glycols on inactivation of mycoplasma pulmonis and acholeplasma laidlawii a. 19827186082
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 ...19826889758
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 ...19826750757
[equine mycoplasma typing using the direct immunofluorescence technic]. 19826764691
membrane lipid fluidity and physical state and the activity of the na, mg-atpase of acholeplasma laidlawii b. 198219431488
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 ...19817217074
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 ...19817240083
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 ...19817240087
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 ...19817250125
studies on acholeplasma laidlawii grown on branched-chain fatty acids. 19817259182
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 ...19817260084
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 ...19817263616
detection of mycoplasmal contaminants in sera. 19817275992
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. ...19817278710
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 ...19817286852
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 ...19817286853
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 ...19817295188
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 ...19817306495
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 ...19817318830
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 ...19817337908
distribution of ureaplasmas in the urogenital tract of ewes. 19817344258
isolation of mycoplasma from a buffalo (bubalus bubalis) with mastitis. 19817199239
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 ...19817213607
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 ...19817213725
a note on positive bactec readings produced by mycoplasma. 19817024236
altered surface structure of acholeplasma laidlawii induced by mycoplasmavirus l3 infection. 19816456906
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. 19816256386
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 ...19816274406
[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 ...19816787821
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 ...19816793538
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.19816793734
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 ...19816797154
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 ...19816169683
selective killing of mycoplasmas from contaminated mammalian cells in cell cultures. 19806156417
methylation patterns of mycoplasma transfer and ribosomal ribonucleic acid.the methylation patterns of transfer and ribosomal ribonucleic acid (rna) from two mycoplasmas, mycoplasma capricolum and acholeplasma laidlawii, have been examined. the transfer rna from the two mycoplasmas resembled that of other procaryotes in degree of methylation and general diversity of methylated nucleotides, and bore particular resemblance to bacillus subtilis transfer rna. the only unusual feature was the absence of m5u from m. capricolum transfer rna. the methylation patterns of the my ...19806160144
membrane lipid physical state and modulation of the na+,mg2+-atpase activity in acholeplasma laidlawii b.careful analysis of the arrhenius plot of the na+,mg2+-atpase (atp pyrophosphohydrolase, ec 3.6.1.8) activity in acholeplasma laidlawii b membranes of varying fatty acid composition has been combined with differential thermal analysis of the membrane lipid phase transitions to evaluate the effects of membrane lipid properties on the enzyme activity. our results indicate that the enzyme is active only in association with liquid-crystalline lipids, exhibiting a significant heat capacity of activat ...19806445554
[proteins of bacterial membranes. purification of soluble atpase from acholeplasma laidlawii].a purified preparation of atpase (factor f1) from the acholeplasma laidlawii was obtained. the purification procedure included extraction of the enzyme complex from the isolated membranes by ultrasonication, chromatography on deae-cellulose and gel filtration on sepharose 6b. the specific activity of the atpase was increased 30-fold as compared to the original activity. the km value for atp hydrolysis was 7,4 . 10(-4) m. adp competitively inhibited the enzyme (ki = 2,0 . 10(-4) m). ouabain (2,5 ...19806452174
effects of charged cholesteryl esters on mycoplasma growth. 19807215545
control of membrane polar lipid composition in acholeplasma laidlawii a by the extent of saturated fatty acid synthesis.the low level of endogenous fatty acid synthesis in acholeplasma laidlawii a strain ef22 was found to be caused by a deficiency of pantetheine in the lipid-depleted growth medium. by supplementing the oleic acid-containing medium with increasing concentrations of pantethein, saturated fatty acid synthesis was stimulated (having an apparent km of 5 microm for pantetheine) and the incorporation of endogenously synthesized fatty acids in membrane lipids increased markedly. furthermore, carotenoid b ...19807352994
lipid chain order in acholeplasma laidlawii membranes. what does 2h nmr tell us? 19807353632
lipid and protein composition and thermotropic lipid phase transitions in fatty acid-homogeneous membranes of acholeplasma laidlawii b.the membrane composition and lipid physical properties have been systematically investigated as a function of fatty acid composition for a series of acholeplasma laidlawii b membrane preparations made homogeneous in various fatty acids by growing cells on single fatty acids and avidin, a potent fatty acid synthetic inhibitor. the membrane protein molecular weight distribution is essentially constant as a function of fatty acid composition, but the lipid/protein ratio varies over a 2-fold range w ...19807370250
inactivation of mycoplasma in serum with binary ethyleneimine.a method of inactivating mycoplasma contaminants in sera by using binary ethyleneimine was tried. when used at the concentration recommended for inactivating viruses, 0.001 m, binary ethyleneimine inactivated only two of five mycoplasma species. even at a concentration of 0.01 m, the compound did not consistently inactivate all mycoplasmas.19807372800
colony morphology, ultrastructure and morphogenesis in mycoplasma hominis, acholeplasma laidlawii and ureaplasma urealyticum.colonies of mycoplasma hominis, acholeplasma laidlawii (three strains) and ureaplasma urealyticum were examined by light and electron microscopy and their characteristic morphology, ultrastructure and morphogenesis are described. mycoplasma hominis and a. laidlawii, pg8 and oral strains, developed typical 'fried-egg' colonies which were remarkably heterogeneous in size. the colonies of a. laidlawii strain nctc 10116 were more homogeneous and grew mainly on the surface of the agar showing a fine ...19807373281
ultrastructural study of the interaction between acholeplasma laidlawii and antibody.the ultrastructure of agar-grown acholeplasma laidlawii incubated with specific antiserum or igm fractions of this antiserum has been investigated by the thin-sectioning technique. antiserum treatment resulted in the development of giant cells along the colony circumferences and in the coating of normal-size mycoplasmas with a periodically arranged extramembranous layer, consisting of attached immunoglobulins as shown by indirect immunoferritin labelling. the regular structure of the coat was no ...19807373282
a survey of mycoplasma infections in domestic poultry.a survey of mycoplasma infections of chickens, turkeys and ducks was made on tissues from a variety of sources and birds of various ages, and from pipped and dead-in-shell turkey embryos. the tissues examined consisted mainly of respiratory tissue and the cloaca and contents and also a small number of joint lesions and other tissues. from chickens, mycoplasmas were isolated from a total of 138 tissues with mycoplasma gallisepticum in preponderance. this was followed by m gallinarum, untyped orga ...19807375739
phospholipid and cholesterol uptake by mycoplasma cells and membranes.the ability of growing mycoplasma cells and their isolated membranes to take up exogenous phospholipids was correlated with their ability to take up cholesterol. horse serum or vesicles made of phosphatidylcholine and cholesterol served as lipid donors. growing cells of five mycoplasma species took up significant quantities of phosphatidylcholine and sphingomyelin as well as free and esterified cholesterol. in contrast, growing cells of three acholeplasma species failed to take up any of the exo ...19807388026
isoenzymes in two species of acholeplasma.the reference strains type a and type b and two equine strains of acholeplasma laidlawii were examined for a wide range of isoenzymes using thin-layer starch-gel electrophoresis; in addition two isoenzymes were examined in two strains of a. equifetale. the type strains a and b of a. laidlawii were differentiated by their lactate dehydrogenase, phosphoglucomutase and aspartate aminotransferase patterns and the two equine strains by their hexokinase, lactate dehydrogenase and phosphoglycerate kina ...19807391817
lipid bilayer stability in membranes. regulation of lipid composition in acholeplasma laidlawii as governed by molecular shape.the polar lipid composition in membranes of acholeplasma laidlawii is extensively regulated as a response to environmental changes. in particular, the ratio between the dominating lipids monoglucosyldiglyceride and diglucosyldiglyceride is altered depending on temperature, configuration of incorporated fatty acids, and membrane cholesterol content. synthesis of monoglucosyldiglyceride is stimulated by low temperature and saturated fatty acids but diminished by the presence of cholesterol. these ...19807407064
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 ...19807407113
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 ...19807407129
[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 ...19807407377
[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 ...19807407696
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 ...19807410317
aminopeptidase activity of acholeplasma laidlawii, mycoplasma bovirhinis, mycoplasma dispar and mycoplasma bovis.aminopeptidase activity was demonstrated in extracts of acholeplasma laidlawii, mycoplasma bovirhinis, m. bovis and m. dispar. the enzyme specificity, which differed amongst the mycoplasma species examined, was characterized using 19 aminoacyl-beta-naphthylamides as substrates. the differences were detected after 4 h incubation with the substrates and potentially could be employed to aid in the characterization of certain mycoplasma species.19807411115
virus and host cell dna syntheses during infection of acholeplasma laidlawii by mvl3, a nonlytic cytocidal mycoplasmavirus.the replication of mycoplasmavirus mvl3 in acholeplasma laidlawii k2 host cells was studied by analysis of infected-cell lysates using sedimentation in sucrose gradients and dna-dna hybridization. viral dna replication was found to involve intermediates sedimenting faster than free viral dna, which is a linear, double-stranded molecule of about 26 x 10(6) daltons. after the shutdown of cellular dna synthesis, viral dna synthesis continued for many hours. the fate of cellular and parental viral d ...19807411689
effect of cell membrane composition on the growth and composition of a nonlytic enveloped mycoplasmavirus. 19807414958
[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, ...19807415681
ultraviolet, photodynamic and thermal inactivation of mycoplasmaviruses.the ultraviolet light, photodynamic, and thermal inactivation parameters have been measured for the three groups of mycoplasmaviruses. the differences in these parameters for the three virus groups reflect differences in virion structure and in genome size and structure.19807421606
methylated bases in mycoplasmal dna.the dnas of four mycoplasma and one acholeplasma species were found to contain methylated bases. all of the five species contained 6-methyladenine (m6ade), the methylated base characteristic of prokaryotic dna. the extent of methylation of adenine residues in the mycoplasmal dna ranged from 0.2% in mycoplasma capricolum to about 2% in mycoplasma arginini and mycoplasma hyorhinis with intermediate methylation values for mycoplasma orale and acholeplasma laidlawii dnas. about 5.8% of the cytosine ...19807433124
interaction of mycoplasma virus type 2 with cellular components of acholeplasma laidlawii strain ja1.mycoplasma virus type 2 was shown to adsorb specifically to intact cells, membranes, and lipoglycan of acholeplasma laidlawii strain ja1 but not to these components of acholeplasma oculi. the oligosaccharide chain of the lipoglycan defined the specificity of the receptor site since deacylation not only did not reduce adsorption but increased it threefold. actual adsorption of virus to lipoglycan was demonstrated by sucrose density gradient separation of the virus-lipoglycan complex. a strain of ...19807441818
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 ...19807441822
[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 ...19807448391
giant cell formation in acholeplasma laidlawii, strain ja1.striking alterations, which looked like blebs, were observed in colonies of acholeplasma laidlawii, strain ja 1. "craters" were seen on the surface of these colonies by scanning electron microscopy. in addition, giant cells of acholeplasma, up to 14 microns in diameter, i.e. approximately 20 times the size of a normal a. laidlawii cell, were visible in the colonies. the large forms were surrounded by a unit membrane. after infection with group 1 and group 2 mycoplasma-viruses, the proportion of ...19807467914
dialogue between membranes and their lipid-metabolizing enzymes. 19806768613
[polysaccharide participation in bacterial wall permeability]. 19806773273
a novel method for the determination of electrical potentials across cellular membranes. ii. membrane potentials of acholeplasmas, mycoplasmas, streptococci and erythrocytes.the membrane potentials of acholeplasma laidlawii, mycoplasma mycoides subsp. capri, mycoplasma gallisepticum, streptococcus faecalis and human erythrocytes have been determined by applying a novel technique. the membrane potentials were calculated simply from potassium concentrations determined by atomic absorption spectroscopy, and gravimetry. the versatility of the new technique is demonstrated by comparing our results with data obtained by different techniques.19806773575
[use of the growth inhibition test, the cft, and the agar gel diffusion precipitation test to identify mycoplasmae isolated from monkeys].the data are presented on comparative evaluation of the growth inhibition test (git), the diffuse precipitation test in agar gel (dptag) and the complement fixation test (cft) in the identification of mycoplasma isolated from monkeys. the results obtained in the study of 4 mycoplasma strains from the internal organs of monkeys in the cft and the dptag with hyperimmune rabbit sera provided by microbiological associates, bethesda, maryland, usa, allowed these mycoplasma to be identified as m. laid ...19806778034
acholeplasma laidlawii membranes: a fourier transform infrared study of the influence of protein on lipid organization and dynamics.fourier transform infrared spectroscopy is applied to the study of intact and deproteinated plasma membranes of acholeplasma laidlawii, enriched biosynthetically with perdeuteriopalmitoyl chains. the temperature-dependent behavior is monitored via the cd stretching modes and compared with that observed in the model membrane 1,2-diperdeuteriopalmitoyl-sn-glycero-3-phosphocholine. the broad ramplike transition observed in the natural membranes is shown to consist of two overlapping stages. in the ...19806892608
the temperature dependence of molecular order and the influence of cholesterol in acholeplasma laidlawii membranes.2h nuclear magnetic resonance (nmr) of acholesplasma laidlawii membranes grown on a medium supplemented with perdeuterated palmitic acid shows that at 42 degrees c or above, the membrane lipids are entirely in a fluid state, exhibiting the characteristic 'plateau' in the variation of deuterium quadrupolar splitting with chain position. between 42 and 34 degrees c there is a well-defined gel-to-fluid phase transition encompassing the growth temperature of 37 degrees c, and at lower temperatures t ...19806892886
phospholipid polymers--synthesis and spectral characteristics.a new approach has been developed for the study of model and natural biomembranes. this involves the cross-linking of diacetylene groups after ultraviolet irradiation. for the study of model biomembranes, pure phospholipids (phosphatidylcholines) have been synthesized containing diacetylene groups in each acyl chain. the physical properties of these lipids have been examined and the conditions under which they polymerise have been determined. polymerisation occurs when the lipid is in a crystall ...19806893417
[immunologic and functional activity of the lymphocytes of mice infected with acholeplasma laidlawii and rauscher virus]. 19806988017
disposition of exposed antigens on the faces of isolated mycoplasma gallisepticum membranes.the transverse disposition of exposed protein antigens on the two faces of isolated mycoplasma gallisepticum membranes have been investigated by using indirect immunoferritin labeling to accomplish visualization of the antigens at the ultrastructural level. comparison between the labeling patterns obtained with unabsorbed specific mycoplasma antiserum and antiserum from which antibodies directed against outer side determinants had been removed revealed that the majority of protein antigens were ...19806991483
distinguishing between mn-containing and fe-containing superoxide dismutases in crude extracts of cells. 19806994652
[submicroscopic organization of certain mycoplasma species].the following mycoplasma species have been studied by the method of ultrathin sections: a. laidlawii, m. hominis, m. arthritidis, m. gallesepticum. after fixation both in the presence and in the absence of sucrose and magnesium material of medium electron density, resembling a microcapsule, could be detected on the surface of all mycoplasmas under study. the cytoplasmic membranes of a. laidlawii, m. hominis and m. arthritidis had a symmetric or asymmetric profile, depending on the method of fixa ...19806996392
[mycoplasmas isolated from the genital tract of mares (author's transl)].mycoplasmas were isolated from 11 (=#6,8%) of 161 cervix swabs from infertile mares. a total of 17 strains was isolated and characterized by indirect immunofluorescent test and metabolic inhibition test as mycoplasma equigenitalium (11 strains), mycoplasma subdolum (2 strains), acholeplasma laidlawii (3 strains) and acholeplasma equifetale (1 strain). in addition cervix swabs of the mares were investigated for bacteria. there was no specific correlation between presence of mycoplasmas and bacter ...19806999784
differentiation of mycoplasmatales from bacterial protoplast l-forms by assay for penicillin binding proteins.membrane proteins with the specific ability for binding penicillin with high affinity (penicillin binding proteins) were found to be present in two strains of the cell wall-less protoplast l-form of p. mirabilis and were absent from different species of mycoplasma and from acholeplasma laidlawii. thus, the assay for penicillin binding proteins appeared to be suitable for the differentiation of the cell wall-less procaryotes. the absence of penicillin binding proteins from the mycoplasmatales fur ...19807004379
[investigation of mare sera for antibodies against acholeplasmas and mycoplasmas with ther enzyme linked immunosorbent assay (elisa) (author's transl)].after abortion sera were taken from 58 thoroughbred and other mares of the northwestern part of germany and investigated by elisa (enzyme linked immuno-sorbent assay) for antibodies against mycoplasma equirhinis, m. subdolum, m. equigenitalium, m. pulmonis, m. felis, acholeplasma laidlawii, a. hippikon, and a. equifetale. reactions at serum dilutions of 1:32 and higher were considered as positive. at serum dilution 1:32 no antibodies were found in 11 sera. the remaining sera showed antibodies ag ...19807006267
fractionation of membranes from acholeplasma laidlawii a on the basis of their surface properties by partition in two-polymer aqueous phase systems.acholeplasma laidlawii a consists of pleomorphic cell clusters surrounded by a single membrane. when lysed, a cell gives rise to several membrane fragments which cannot be separated from each other by isopycnic sucrose gradient centrifugation. a heterogeneous lateral organization of the cell membranes was detected by countercurrent distribution of membrane fragments in a two-polymer aqueous phase system. it revealed that the membranes consist of at least two subpopulations with respect to surfac ...1979760784
lipid reorganization in biological membranes: a study by fourier transform infrared difference spectroscopy.the first application of infrared difference spectroscopy to the study of a natural biological membrane is described. perdeuterated palmitic acid was incorporated biosynthetically into the lipids of the plasma membrane of acholeplasma laidlawii and the temperature-induced structural rearrangement of the endogenous lipids monitored via their c--2h vibrational modes. changes in infrared parameters were studied between 0 and 50 degrees c and contrasted with those occurring in the model membrane sys ...1979760788
[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
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
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
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
the effect of high hydrostatic pressure on the membrane-bound atp-ase of acholeplasma laidlawii b [proceedings]. 1979160925
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