TitleAbstractYear(sorted descending)
decrease in catalase activity of cultured cells by mycoplasma gallisepticum infection.the effect of mycoplasma gallisepticum infection on the host cell catalase activity was histochemically examined in cultured chicken embryo fibroblasts (cef) and kidney cells. the activity in normal cells was detected as fine, brown granules in the cytoplasm, which appeared ultrastructurally to correspond to anucleoid microbodies. by infecting cultured cells with a cef-passaged strain of m. gallisepticum, the catalase-positive granules clearly decreased in amount, whereas the uv light-killed myc ...19873604054
mycoplasma gallisepticum strain variations detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.various strains of mycoplasma gallisepticum (mg) were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. minor but distinct and reproducible differences in protein banding patterns were detected between strains, which included the vaccine f strain from various sources, an atypical (variant) strain, and the standard (a5969, s6) strains.19873619825
evaluation of respiratory lesions in chickens induced by mycoplasma gallisepticum. 19873626242
inhibition of nadh oxidase and lactate dehydrogenase of mycoplasma gallisepticum by copper complexes of 2,2'-bipyridyl the presence of copper, 2,2'-bipyridyl analogues possess growth-inhibitory activity against mycoplasma gallisepticum. inhibition of the energy yielding metabolism plays a role in the mechanism of action. we showed that probably inhibition of lactate dehydrogenase and nadh oxidase is involved. both enzymes were inhibited in vitro and in vivo by several copper 2,2'-bipyridyl complexes. a two-step mechanism of action is proposed, i.e. first a copper complex enters the cell, then after dissociati ...19873663238
a species-specific dna probe for the detection of mycoplasma 800-base-pair dna fragment from a partial genomic library of mycoplasma gallisepticum was selected and used as a probe for the selective detection of this avian pathogen. the specificity and sensitivity of this probe were demonstrated by using dot blot and southern hybridizations.19873666965
sealed vesicles prepared by fusing mycoplasma gallisepticum membranes and preformed lipid vesicles.sealed vesicles were obtained by fusing mycoplasma gallisepticum membranes with asolectin-cholesterol vesicles. the fusion was induced by freezing and thawing followed by a brief sonication treatment and was detected using a fluorescence sedimentation behavior in a sucrose density gradient and were shown to be impermeable to small solutes. the advantages of such fused preparations for transport studies in mycoplasmas are discussed.19873667215
kinetics of cholesterol and phospholipid exchange between mycoplasma membranes and lipid vesicles.the following modifications in the lipid composition of mycoplasma gallisepticum or m. capricolum membranes led to changes in the rates of [14c]cholesterol and [14c]phospholipid exchange between cell membranes and an excess of small unilamellar vesicles: 1) increase in the cholesterol/phospholipid molar ratio from 0.25 to 0.92; 2) incorporation of synthetic, cross-linked phosphatidylethanolamine (pe) derivatives, 3) incorporation of sphingomyelin (spm); and 4) increase in the phosphatidylglycero ...19873667216
development of a biotinylated probe for the rapid detection of mycoplasma gallisepticum.mycoplasma gallisepticum causes respiratory diseases in the form of tracheitis and air sacculitis in chickens and turkeys. it is a major cause of reduced egg production, reduced hatchability, and downgrading of carcasses. current means of diagnosis depend on the isolation and identification of the organisms, or on serological assays to detect serum antibodies. the evaluation of avian sera for m. gallisepticum antibodies is becoming more difficult to interpret, and thus less useful, due to the in ...19873667241
evaluation of factors associated with infection of commercial layers with mycoplasma gallisepticum and m. synoviae.information on factors possibly associated with the risk of infection with mycoplasma gallisepticum (mg) or m. synoviae (ms) were collected from nearly 400 layer flocks in california. factors associated with the probability of flock infection with either mg or ms were identified, and their magnitude was quantified by statistical analysis. more frequent administration of several vaccines was associated with decreased probability of both mg and ms infection of flocks. also identified were housing ...19873675422
economic impact of mycoplasma gallisepticum and m. synoviae in commercial layer egg-production function was constructed, using data collected from 366 commercial layer flocks in california, to predict the impact of mycoplasma gallisepticum (mg) and m. synoviae (ms) on egg production while controlling for confounding factors. in the first and second cycles, respectively, an mg-infected flock produced 12 and 5 fewer eggs per hen than an uninfected flock. flocks that became infected with mg after f-strain vaccination produced 6 eggs/hen more than unvaccinated infected flock ...19873675423
comparison of culturing mycoplasma gallisepticum from fresh eggs and 18-day-old embryos.twenty-four 70-week-old and sixteen 27-week-old white leghorn hens were challenged with r strain mycoplasma gallisepticum (mg) by injection into the caudal thoracic air sac and infraorbital sinus. eggs were collected daily and cultured within 7 days or incubated for 18 days. vitelline membranes of eggs were cultured directly; in 18-day-old embryos, cultures were taken from the yolk sac, air sacs, and oral cavity. culture of vitelline membrane of eggs within 2 days was compared with culture of eg ...19873675426
[detection and identification of mycoplasma infections by dna hybridization].infection of cell cultures by mycoplasmas can be detected by hybridization of the dna of suspected cell cultures with recombinant plasmids containing fragments of the mycoplasma dna. the test is very sensitive and allows detection of as little as 1 ng of mycoplasmal dna, roughly equivalent to the dna amount of 10(6) mycoplasmas. this approach turns out to be effective for detection and identification of mycoplasmas in clinical material, plant and insect tissues. a set of dna probes for detection ...19873318046
control of sodium fluxes in mycoplasma gallisepticum.swelling of mycoplasma gallisepticum cells when incubated in a glucose-free isoosmotic nacl buffer was shown to be due to the entrance of nacl into the cell. volume regulation therefore depends on na+ extrusion. the mechanism of na+ extrusion in cells and proteoliposomes, prepared from m. gallisepticum membrane fragments, was investigated by following both 22na+ efflux and ph changes. our results indicate that na+ is expelled from cells via two separate mechanisms, an na+/cation exchange mechani ...19872822608
pathological and immunological studies on chicken embryos and day-old chicks experimentally infected with mycoplasma gallisepticum. 19862953204
the beta-subunit of the f1f0-atpase is conserved in mycoplasmas.monospecific polyclonal antibodies that were generated against the beta-subunit of escherichia coli atpase (f1fo) cross-reacted with a protein present in the cells of several mycoplasma and acholeplasma species. in mycoplasma gallisepticum, the reactive protein was found almost exclusively in the cell membrane. this protein had an apparent molecular mass of approximately 52 kda and could not be released from the membranes by repeated washings with either low or high salt solutions in the presenc ...19862872212
antigenic determinants of the attachment protein of mycoplasma pneumoniae shared by other pathogenic mycoplasma previous studies with hyperimmune rabbit antisera, we found evidence of serologic cross-reactivity among mycoplasma pneumoniae, mycoplasma genitalium, and mycoplasma gallisepticum. because of certain biologic and morphologic similarities of these species, attempts were made to determine if this cross-reactivity related to the attachment protein (p1) of m. pneumoniae. monoclonal and monospecific antibodies against p1 were used to probe proteins of the other species by immunoblotting. one of th ...19862417956
detection and differentiation of mycoplasma gallisepticum and m. synoviae antibodies in chicken serum using enzyme-linked immunosorbent assay.affinity-purified sheep igg anti-chicken igg horseradish peroxidase conjugate was utilized in an enzyme-linked immunosorbent assay (elisa) to detect mycoplasma gallisepticum- and m. synoviae-specific antibodies in chicken sera. antigen, conjugate and substrate concentrations, and incubation times were adjusted to provide maximum differentiation between positive and negative sera. use of phosphate-buffered saline containing 0.05% tween 20 for washing and diluting steps and use of normal sheep ser ...19863729859
evaluation of protection against mycoplasma gallisepticum infection in chickens vaccinated with the f strain of m. gallisepticum.the effect of vaccination with the f strain of mycoplasma gallisepticum (mg) on protection against challenge with a tylosin-resistant strain of mg was evaluated. white leghorn chickens vaccinated via eyedrop at 6 weeks of age were subsequently challenged with various dilutions of the tylosin-resistant mg strain, as were unvaccinated controls. three days later, tracheal swabs were collected and cultured in medium with and without tylosin to distinguish between the vaccine and challenge strains. t ...19863729860
triton x-100-solubilized mycoplasma gallisepticum and m. synoviae elisa antigens.triton x-100-solubilized mycoplasma gallisepticum and m. synoviae elisa antigens were found to be more specific and sensitive than six other antigens at a concentration of 250 ng protein/0.1 ml per microtiter plate well.19863729864
infectious sinusitis in coturnix quails in brazil, mycoplasmas were isolated from the sinuses of japanese quails (coturnix coturnix japonica) from two commercial flocks affected with sinusitis. the major respiratory signs and gross lesions are described. based on serological and biochemical results, the mycoplasmas isolated were identified as mycoplasma gallisepticum. one of the isolates was pathogenic for chickens.19863729866
observations on commercial layers vaccinated with mycoplasma gallisepticum (mg) bacterin on a multiple-age site endemically infected with mg.a commercially available inactivated mycoplasma gallisepticum (mg) bacterin was administered to chickens on a multiple-age farm endemically infected with mg. a total of 3400 mg-free pullets were vaccinated with the mg bacterin at 19 weeks of age, and 4300 unvaccinated pullets served as controls. the vaccinated group became serologically positive by the rapid plate agglutination (rpa) test within 3 weeks, and the unvaccinated group became positive in 7 weeks. the hemagglutination-inhibition test ...19863729876
response of chickens to inoculation with a temperature-sensitive mutant of mycoplasma gallisepticum.newly hatched chickens were inoculated intranasally with either the s6 or ts 100 strain of mycoplasma gallisepticum (mg) or they were left uninoculated. the three groups of chickens did not differ discernibly in body, spleen, or bursa weight during the 27-day sampling period. however, the s6-inoculated chickens showed a more pronounced cellular response in the nasal passages and had nearly complete lymphoid depletion in the spleens. the ts 100-inoculated birds expressed only a mild cellular reac ...19863729884
a statistical model to optimize enzyme-linked immunosorbent assay parameters for detection of mycoplasma gallisepticum and m. synoviae antibodies in egg enzyme-linked immunosorbent assay (elisa) was developed to quantify mycoplasma gallisepticum (mg) and m. synoviae (ms) antibodies in egg-yolk extract. various parameters of elisa were evaluated and optimized. a statistical model was developed to study the relationship between elisa absorbance (a) and antigen concentration, antibody concentration, and time of reading of the test. these factors explained 62% of the variability in a for the mg antigen and 74% of the variability in a for the ms a ...19863729885
comparison of egg yolk and serum for the detection of mycoplasma gallisepticum and m. synoviae antibodies by enzyme-linked immunosorbent assay.egg yolk was evaluated in the enzyme-linked immunosorbent assay (elisa) as an alternative source of antibodies for detection of mycoplasma gallisepticum (mg) and m. synoviae (ms) infections in chickens. there was no statistically significant difference (p greater than 0.05) between the elisa geometric mean titers (gmts) of saline-diluted egg yolk and chloroform-extracted egg yolk, and both preparations had a high correlation coefficient (0.87 for mg; 0.97 for ms). the saline-diluted and chlorofo ...19863729886
31p-nmr studies of mycoplasma gallisepticum cells using a continuous perfusion technique.31p-nmr studies of mycoplasma gallisepticum cells have been carried out using a continuous perfusion technique; these are the first such studies with this organism. using this technique, glucose metabolism was monitored in the intact organisms, and cell extracts were prepared to identify the intermediates. under glycolytic conditions, high levels of fructose-1,6-diphosphate were observed, indicating that this sugar may play a key role in the regulation of metabolism. the level of phosphoenolpyru ...19863732520
effects of dose of antigen and social environment on antibody response of high and low antibody response chickens.chickens selected for high (ha) and low (la) antibody response were exposed to 10-fold doses of red blood cell and killed bacterial antigens while in three different social environments. antibody responses of the ha and la line chickens differed most in the socialized environment and at lower doses of antigen. dose effects were most pronounced in la-line chickens whereas relationship of humans to chickens was most important to ha-line chickens. socialized chickens were more consistent than ignor ...19863737505
infectious sinusitis associated with mycoplasma gallisepticum in game-birds. 19863753348
prophylactic efficacy of 3-acetyl-4''-isovaleryl tylosin in a mycoplasma gallisepticum-induced airsacculitis infection.formulations of 3-acetyl-4''-isovaleryl tylosin (aiv) were evaluated for oral efficacy in a mycoplasma gallisepticum (mg) airsacculitis infection. aiv administered by gavage, feed, or water was more effective than tylosin in preventing airsacculitis. an aiv tartrate formulation administered in drinking water to chickens infected with a macrolide-sensitive or macrolide-resistant strain of mg resulted in no detection of mycoplasma in the air sacs and in mg-negative sera.19863767811
a historical account of the diagnosis and characterization of strains of mycoplasma gallisepticum of low virulence.numerous chicken flocks were studied beginning in 1970 because of questionable results on their serologic tests for mycoplasma gallisepticum (mg). typically a low number of hens in the flocks were positive reactors to the rapid serum plate test and rarely had hemagglutination-inhibition (hi) titers over 1:80. usually no clinical signs were observed. isolates of mg eventually were cultured from most of the flocks that exhibited that type of marginal serologic pattern. in the laboratory, the mg is ...19863767812
prevalence of mycoplasma gallisepticum and m. synoviae in commercial layers in southern and central california.the prevalence of mycoplasma gallisepticum (mg) and m. synoviae (ms) in commercial pullet and layer flocks in southern and central california was estimated by testing serum and egg-yolk samples from 360 sample flocks in southern california and 41 sample flocks in central california. data relating to potential risk factors associated with mg and ms infections were collected. the estimated true prevalence rate of mg was 73% in southern california and 3% in central california. the estimated true pr ...19863767813
antibody responses in sera and respiratory secretions from chickens infected with mycoplasma gallisepticum.antibodies in sera and respiratory secretions from chickens infected with mycoplasma gallisepticum (mg) were measured by an enzyme-linked immunosorbent assay (elisa). chickens intratracheally inoculated with 10(5) cells of mg showed a correlation between severity of tracheal lesions and extent of mg colonization in the tracheas in the first 3 weeks postinoculation. antibody titers in tracheal washings (tws) of the infected chickens increased during this phase. thereafter, isolation of mg from th ...19863767815
effect of medicated feed on tracheal infection and population of mycoplasma gallisepticum in chickens.six-week-old broilers were fed 50 g tylosin/ton, 400 g chlortetracycline (ctc)/ton, or unmedicated feed and then challenged intratracheally with r strain mycoplasma gallisepticum (mg). feed-grade antibiotic medication did not prevent infection, but medication did lower the number of isolations from treated birds compared with controls. only tylosin significantly lowered mg counts in the trachea. the log10 id50 of birds receiving tylosin, ctc, or unmedicated feed were 5.8, 4.4, and 2.9, respectiv ...19863767816
a radioimmunoassay for the detection of antibodies to mycoplasma gallisepticum.a radioimmunoassay technique was developed to determine the antibodies to mycoplasma gallisepticum (mg) in sera, yolk fluids, and tracheal washings.19863767822
properties of mycoplasma gallisepticum grown in a medium supplemented with liposomes as a substitute for serum. 19863796324
effect of temperature-sensitive mycoplasma gallisepticum vaccine preparations and routes of inoculation on resistance of white leghorns to chickens were vaccinated with live or formalin-killed temperature-sensitive (ts) mycoplasma gallisepticum (mg) either intranasally (in) or subcutaneously (sq). live ts mg protected chickens against s6 strain challenge directly into the air sacs, regardless of route of vaccination. killed mg, however, protected chickens only when administered sq. antibody to mg was detected in sera and in the tracheal and air-sac washings of only the chickens given live vaccine in. the antibody prese ...19863814015
influence of hatcher holding times on several physiological parameters associated with the immune system of chickens.two experiments were conducted with broiler chicks to study the effects of posthatch holding time in the incubator on physiological and disease parameters. in each experiment, half of the chicks were removed shortly after hatching and half of the chicks were allowed to remain in the hatcher for an additional 30 hr. bursa weights, hematocrits, total plasma protein, and blood glucose concentrations were measured at various times up to 35 and 28 days of age in experiments 1 and 2, respectively. in ...19863822996
detection of mycoplasma gallisepticum by direct immunofluorescence using a species-specific monoclonal antibody.a monoclonal antibody against mycoplasma gallisepticum (mg) (strain s6) was prepared in mice and identified as isotype igg1 by standard procedures. although it did react at high titers (1:100,000) in the enzyme-linked immunosorbent assay (the original method for its identification), it failed to react in the agglutination, hemagglutination-inhibition, and growth-inhibition tests. when conjugated to fluorescein isothiocyanate, the monoclonal antibody reacted with the homologous and eight "atypica ...19863524541
interaction of albumin and phospholipid:cholesterol liposomes in growth of mycoplasma spp.mycoplasma spp., sterol and fatty acid auxotrophs, are conventionally grown in complex media containing high concentrations of serum. serum supplies the required lipids, but its presence complicates studies on the metabolism and antigenicity of mycoplasmas as well as the membrane dynamics of these organisms. in the present work, fetal bovine serum was replaced with dilipidated albumin and liposomes containing high concentrations of cholesterol. the liposomes were produced from phosphatidylcholin ...19863954343
comparison of in vivo and in vitro methods for pathogenicity evaluation for mycoplasma gallisepticum in respiratory infection.this study was designated to examine the pathogenicity of several strains of mycoplasma gallisepticum (r, f, s-6, 227 and a5969) and laboratory derived substrains. preliminary results indicated that the nine m. gallisepticum strains differed markedly in their pathogenicity for chickens. a comparison was made between various in vivo and in vitro methods for quantitative evaluation of pathogenicity. reproducibility, convenience, and relevance to clinical observations were considered. two in vivo t ...198618766523
isolation of mycoplasma gallisepticum from geese.two breeding flocks of 2-year-old geese in the landes region of southwest france were cultured for mycoplasmas. in one flock of 134 birds mycoplasma gallisepticum was isolated from three individuals, from a different site in each bird (i.e. oesophagus, trachea, cloaca). m. gallisepticum was also isolated from the semen of one goose in the other flock of 70 birds, but in neither flock could the true incidence be determined because of prolific overgrowth by acholeplasmas in nearly all the samples.198618766559
evaluation of cytopathologic changes induced in chicken tracheal epithelium by mycoplasma gallisepticum in vivo and in vitro.changes in tracheal epithelial surfaces induced by mycoplasma infection in vivo and in vitro included release of mucous granules followed by exfoliation of ciliated and nonciliated epithelial cells. light microscopy, scanning electron microscopy, and transmission electron microscopy confirmed that the loss of cilia from individual cells was infrequent. epithelial cells typically lost their intercellular connections, rounded up, exfoliated, and then lysed--giving rise to a population of cellular ...19853970413
evaluation of serologic tests for mycoplasma gallisepticum in wild turkeys. 19853981747
in ovo pathogenicity of mycoplasma gallisepticum strains in the presence and absence of maternal antibody.mycoplasma gallisepticum (mg) strains showing marked variation in pathogenicity were examined for virulence in ovo. no correlation was found between in ovo pathogenicity and other in vivo or in vitro methods for pathogenicity evaluation. for certain highly pathogenic strains, there was a clear relationship between the titer of mg inoculated and the embryo mortality and time of death; an ld50 for these strains could be calculated by yolk-sac inoculation. however, not every strain that caused lesi ...19853985874
an enzyme-linked immunosorbent assay for the detection of antibodies to mycoplasma gallisepticum in experimentally infected indirect enzyme-linked immunosorbent assay (elisa) was developed and tested for its ability to detect humoral response to mycoplasma gallisepticum in chickens. two antigens were used in the solid phase of the assay. antigen 1 was a membrane-derived sodium dodecyl sulfate (sds)-solubilized preparation; antigen 2 was prepared in the same manner as antigen 1 but was passed through an immunoadsorbent column containing rabbit anti-medium antibodies. test conditions were optimized for incubation ti ...19853985883
kinetics of cholesterol and phospholipid exchange from membranes containing cross-linked proteins or cross-linked phosphatidylethanolamines.mono- and dipalmitoylphosphatidylethanolamine derivatives have been synthesized and used to evaluate the role of cross-links between the amino groups of two phospholipid molecules in the rate of cholesterol movement between membranes. incorporation of the cross-linked phospholipids into small unilamellar vesicles (the donor species) decreased the rate of spontaneous cholesterol exchange with acceptor membranes (small unilamellar vesicles or mycoplasma gallisepticum cells). these results suggest ...19853986182
comparison of the antimycoplasma activity of two commercially available tylosin premixes.two tylosin premixes (referred to in this report as premix a and tylosin premix b), obtained as commercial products from japan, were analyzed microbiologically for tylosin and by high pressure liquid chromatography (hplc) for macrolide content. they were evaluated in the feed at concentrations of 550 and 1100 ppm antibiotic activity for the treatment of chickens with induced mycoplasma gallisepticum (mg) infection. the tylosin microbiological assay value for premix a was 3.0% below and for premi ...19853991415
mycoplasma gallisepticum vaccination: further studies on egg transmission and egg production.leghorn hens vaccinated twice with an inactivated mycoplasma gallisepticum (mg) bacterin before egg production and subsequently challenged with virulent mg were protected against transmission of mg through the egg. unvaccinated control hens transmitted mg through the egg at a high rate. when unvaccinated hens were vaccinated with mg bacterin 2 weeks after challenge with mg, there was no significant decrease in egg transmission. hens vaccinated twice before laying did not suffer as severe egg-pro ...19854026735
cell volume regulation in mycoplasma gallisepticum.mycoplasma gallisepticum cells incubated in 250 mm nacl solutions in the absence of glucose showed a progressive fall in intracellular atp concentration over a period of 2 to 3 h. when the atp level fell below 40 microm the cell began to swell and become progressively permeable to [14c]inulin and leak intracellular protein and nucleotides. the addition of nondiffusable substances such as mgso4 or disaccharides prevented swelling, suggesting that nacl (and water) entry was due to gibbs-donnan for ...19854030694
sodium and proton transport in mycoplasma gallisepticum.when washed cells of mycoplasma gallisepticum were incubated at 37 degrees c in 250 mm 22nacl, the intracellular na+ increased, and the k+ decreased. the addition of glucose to these na+-loaded cells caused na+ efflux and k+ uptake (both ions moving against concentration gradients). this effect of glucose was blocked by the atpase inhibitor dicyclohexylcarbodiimide, which prevents the generation of a proton motive force in these cells. in additional experiments, na+ extrusion was studied by dilu ...19854030695
presumptive diagnosis of subclinical infections utilizing computer-assisted analysis of sequential enzyme-linked immunosorbent assays against multiple serum samples, collected sequentially from four flocks of egg- and meat-type chickens, were evaluated for antibodies to multiple infectious agents by enzyme-linked immunosorbent assay (melisa). the melisa system used provided simultaneous measurement of antibody titers against avian infectious bronchitis (ib), infectious bursal disease (bd), newcastle disease, avian encephalomyelitis and reovirus infections, and mycoplasma gallisepticum. the use of computer-generated grap ...19854048057
egg production, egg weight, eggshell strength, and mortality in three strains of commercial layers vaccinated with f strain mycoplasma gallisepticum.three strains of commercial leghorns vaccinated at 17 to 22 weeks of age with f strain mycoplasma gallisepticum (mg) were maintained through 117 weeks of age. the three strains differed in both mortality and percent egg production per hen housed; however, the strains did not differ in egg weight (ew), eggshell strength (ess), or percent daily egg production. results of this study indicate ew and ess for f strain mg-vaccinated hens follow patterns previously reported for uninfected layers. furthe ...19854074249
tracheal populations of mycoplasma gallisepticum after challenge of bacterin-vaccinated chickens.chickens vaccinated once or twice with inactivated oil-emulsion vaccine against mycoplasma gallisepticum (mg) or left unvaccinated were challenged intratracheally with the r strain of mg. the population of mg organisms was determined by enumerating tracheal cultures periodically up to 28 weeks postchallenge (pc). the number of organisms in the respiratory tract increased rapidly after 4 days pc, and the number tended to decrease after 4 weeks pc. tracheal populations of mg varied considerably am ...19853833213
bacterin to control the vertical transmission of mycoplasma gallisepticum in chickens.a mycoplasma gallisepticum bacterin was prepared and used in mycoplasma gallisepticum (mg)-positive primary breeders to control vertical transmission of mg. two generations were vaccinated, but the third generation was not vaccinated and was monitored serologically. results showed no evidence of mg at 1 day, 6 weeks, 11 weeks, 16 weeks, or 31 weeks of age. this procedure may offer small breeder organizations and showbird fanciers a way to eliminate mg.19853833226
stability of the f strain of mycoplasma gallisepticum in various diluents at 4, 22, and 37 c.the stability of the f strain of mycoplasma gallisepticum was determined in reconstituted powdered skim milk, phosphate-buffered saline, tryptose phosphate broth, and distilled water at 4, 22, and 37 c. the culture was stable for up to 24 hr in all diluents at 4 and 22 c. at 37 c, the culture was stable up to 24 hr in phosphate-buffered saline, but there was a slight reduction of viability in tryptose phosphate broth at 8 and 24 hr, and the titer was reduced in skim milk at 24 hr. in distilled w ...19853833228
evaluation of protection against colonization of the chicken trachea following administration of mycoplasma gallisepticum bacterin.twelve-week-old commercial white leghorn pullets were given one or two doses of an inactivated oil-emulsion mycoplasma gallisepticum (mg) vaccine or kept as unvaccinated controls. at 24 weeks of age, all groups were challenged intratracheally with one of six dilutions of a low-passage r strain of mg. three days postchallenge, the tracheas from all chickens were cultured for mg to determine the number of challenge organisms required to initiate infection. the log10 id50 of chickens vaccinated 0, ...19853833239
swab absorbability--effect on mycoplasma gallisepticum isolation.a single strain of commercial leghorn vaccinated with f strain mycoplasma gallisepticum (mg) was used in two trials to determine the effect of swab absorbability on mg isolation. for each of the two trials, 34 birds from each of five 10,000 bird houses were randomly selected and swabbed from the choanal cleft region; 17 birds from each house were swabbed with ethylene-oxide sterilized, 2.4-mm diameter calcium alginate-tipped swabs, while the remaining 17 birds were swabbed with similarly sized a ...19853906617
construction of the mycoplasma evolutionary tree from 5s rrna sequence data.the 5s rrna sequences of eubacteria and mycoplasmas have been analyzed and a phylogenetic tree constructed. we determined the sequences of 5s rrna from clostridium innocuum, acholeplasma laidlawii, acholeplasma modicum, anaeroplasma bactoclasticum, anaeroplasma abactoclasticum, ureaplasma urealyticum, mycoplasma mycoides mycoides, mycoplasma pneumoniae, and mycoplasma gallisepticum. analysis of these and published sequences shows that mycoplasmas form a coherent phylogenetic group that, with c. ...19852579388
spiroplasma membrane lipids.membranes of six spiroplasma strains belonging to different spiroplasma species and subgroups were isolated by a combination of osmotic lysis and sonication in the presence of edta to block endogenous phospholipase activity. analysis of membrane lipids showed that in addition to free and esterified cholesterol the spiroplasmas incorporated exogenous phospholipids from the growth medium. sphingomyelin was preferentially incorporated from phosphatidylcholine-sphingomyelin vesicles or from the seru ...19852981796
influence of a 12.5 per cent rapeseed diet and an avian reovirus on the production of leg abnormalities in male broiler chickens.the incidence of different forms of leg abnormality were recorded in reovirus (s1133) infected and control male broiler chickens fed on a normal commercial diet or one of similar nutritive value containing 12.5 per cent rapeseed meal. regular serological examination showed that birds remained free from mycoplasma gallisepticum and m synoviae infection throughout the 10 week period of investigation. precipitating antibodies to the reovirus were detected in 90 per cent of the infected birds betwee ...19852983408
efficacy of experimental inactivated mycoplasma gallisepticum oil-emulsion bacterin in egg-layer chickens.six groups of white leghorn pullets were studied to determine the ability of beta-propiolactone-inactivated mycoplasma gallisepticum (mg) oil-emulsion bacterins to counteract reductions in egg production caused by mg infection. the pullets were inoculated with 0.5 ml of mg bacterin subcutaneously in the neck at about 20 weeks of age and were challenged with mg near 28 weeks of age, when they were in peak egg production. various challenge schemes with infectious bronchitis virus were used at the ...19852992434
characterization and solubilization of the membrane-bound atpase of mycoplasma gallisepticum.the membrane-bound atpase of mycoplasma gallisepticum selectively hydrolyzed purine nucleoside triphosphates and datp. adp, although not a substrate, inhibited atp hydrolysis. the enzyme exhibited a ph optimum of 7.0 to 7.5 and an obligatory requirement for divalent cations. dicyclohexylcarbodiimide at a concentration of 1 mm inhibited 95% of the atpase activity at 37 degrees c, with 50% inhibition occurring at 22 microm dicyclohexylcarbodiimide. sodium or potassium (or both) failed to stimulate ...19853161871
volume regulation in mycoplasma gallisepticum.cells of mycoplasma gallisepticum incubated in 250 mm nacl in the absence of glucose for several hours show swelling and eventual lysis. this swelling is believed to be due to colloid osmotic and donnan forces, since it is prevented by the addition of nondiffusable solutes such as sucrose or mgso4. the addition of glucose during the swelling stage (but before lysis) caused shrinkage and return to initial volume. experiments on na+ and h+ movement are consistent with the operation of an atp-drive ...19846096306
use of egg yolk in serological tests (elisa and hi) to detect antibody to newcastle disease, infectious bronchitis, and mycoplasma gallisepticum.serum and yolks from commercial flocks and from hens exposed to newcastle disease virus (ndv), infectious bronchitis virus (ibv), and mycoplasma gallisepticum (mg) were tested for immunoglobulin g antibody by the enzyme-linked immunosorbent assay (elisa) and the hemagglutination-inhibition (hi) test. yolks prepared by chloroform extraction and low-speed centrifugation performed well in the serological tests used and were a suitable alternative to serum for antibody determination by the elisa for ...19846098252
avian mycoplasma infections: prototype of mixed infections with mycoplasmas, bacteria and viruses.mixed infections involving mycoplasmas, viruses and bacteria are well recognized in chickens. synergism has been demonstrated between mycoplasma gallisepticum and the viruses of newcastle disease and infectious bronchitis and escherichia coli, although the outcome of infection is influenced by many factors associated with the host and the organisms. airsacculitis in broilers due to m. synoviae or m. gallinarum may be precipitated by concurrent respiratory virus infections including vaccine strai ...19846324630
further studies on the immunization of chickens with temperature-sensitive mycoplasma gallisepticum mutant.newly hatched chickens were immunized with a temperature-sensitive (ts) mycoplasma gallisepticum (mg) mutant (ts 100). immunized chickens resisted challenge with the virulent s6 strain. the dose of ts mg needed for protection was less than 3.3 x 10(4) colony-forming units. after immunization with ts 100, chickens were subjected to a variety of virus infection and immunosuppressive treatments. neonatal bursectomy or thymectomy, infectious bursal disease virus infection, and infectious bronchitis ...19846326734
the effect of oil-emulsion vaccines on the occurrence of nonspecific plate agglutination reactions for mycoplasma gallisepticum and m. synoviae.six groups of ten 18-week-old mycoplasma-free white leghorn pullets were vaccinated with one of the following: mycoplasma gallisepticum (mg) bacterin. haemophilus gallinarum bacterin, pasteurella multocida bacterin, combined infectious bursal disease (ibd)-newcastle (ndv) chicken-embryo-origin (ceo) vaccine. ibd-ndv tissue-culture-origin (tc) vaccine, or saline emulsified in oil; one group received no vaccine. plate agglutination tests for m. synoviae (ms) and mg were done for 10 weeks after vac ...19846331364
influence of mycoplasma gallisepticum, infectious bronchitis, and cyclophosphamide on chickens protected by native intestinal microflora against salmonella typhimurium or escherichia coli.chickens that have considerable resistance to salmonella typhimurium or escherichia coli infection by early development of a native intestinal microflora shed these bacteria following aerosol exposure to mycoplasma gallisepticum and/or infectious bronchitis virus. administration of cyclophosphamide to similarly treated chickens induced slight shedding of these bacteria, and the combination of cyclophosphamide and respiratory agents magnified the shedding rate. these agents also influenced the is ...19846331365
improving the mycoplasma gallisepticum and m. synoviae antigen yield by readjusting the ph of the growth medium to the original alkaline state.the ph of mycoplasma gallisepticum (mg) and m. synoviae (ms) growth medium was readjusted back to the original alkaline state when the ph reached 6.1 (for mg) and 6.7 (for ms), and the medium was reincubated until the ph of the medium returned to 6.7 to 6.9. the result was that mg and ms antigen yields were 43 and 54% higher than yields obtained at the usual harvest time.19846372778
a urease-elisa for the detection of mycoplasma infections in elisa utilising a urease-antibody conjugate specific to chicken igg was examined as an alternative to the serum agglutination and the haemagglutination inhibition tests in the diagnosis of mycoplasma gallisepticum and m. synoviae infections in poultry. use of a urease conjugate allowed the serum reactions to be appraised without the need for expensive photometric equipment. non-specific binding of conjugate to antigen was eliminated by treatment of antigen coated microplates with 10% foetal c ...19846378168
mycoplasma gallisepticum isolation in layers.mycoplasma gallisepticum (mg) isolations in live chickens have been made from swabs obtained primarily from the trachea or nasal exudates. as tracheal swabs are often contaminated with feed and because tracheal swabbing may be stressful to the bird, this study was conducted to determine if swabs from the choanal cleft (palatine fissure) would yield mg isolation rates comparable to mg isolation rates of swabs taken from the trachea. commercial leghorns from 17 to 22 weeks of age were inoculated v ...19846387691
absence of mycoplasma pneumoniae cytadsorption protein p1 in mycoplasma genitalium and mycoplasma gallisepticum.polyclonal and monoclonal antibodies to mycoplasma pneumoniae protein p1 were nonreactive with whole-cell or soluble preparations of m. genitalium and m. gallisepticum. however, radioimmunoprecipitation performed with hyperimmune rabbit sera raised against each mycoplasma species indicated antigenic cross-reactivity between m. pneumoniae and m. genitalium.19846421736
the adhesins of mycoplasma gallisepticum and m. pneumoniae.the growth of m. gallisepticum was monitored in regard to their capacity to haemagglutinate. the maximal potential was with cells grown for about 22 h. m. gallisepticum, like m. pneumoniae, possess a triton shell intracellular filamentous structure which is revealed by exposing the cells to a relatively low concentration of triton-x100. the adhesin of m. gallisepticum was partially purified on sialoglycopeptide conjugated to sepharose-4b. the adhesin fraction was primarily composed of one polype ...19846424524
demonstration of mycoplasma gallisepticum in tracheas of healthy carrier chickens by fluorescent-antibody procedure and the significance of certain serologic tests in estimating antibody response.chickens naturally infected with mycoplasma gallisepticum (mg) were cultured by tracheal swab. although the chickens showed no signs of disease, they remained mg carriers many months after the acute phase of infection. when mg was isolated from tracheas, the agent was demonstrated also in smear preparations from tracheal mucus by the indirect fluorescent-antibody procedure. humoral immune response to mg was low, as detected by rapid serum-plate-agglutination, micro-tube-agglutination, hemaggluti ...19846435592
decreases in rates of lipid exchange between mycoplasma gallisepticum cells and unilamellar vesicles by incorporation of sphingomyelin.the kinetics of exchange of radiolabeled cholesterol and phospholipids between mycoplasma gallisepticum cells and an excess of small unilamellar phospholipid/cholesterol vesicles were studied using cells enriched with different phospholipid classes but the same fatty acyl content. the rates of the rapidly exchanging cholesterol and phospholipid pools were markedly slower in sphingomyelin-containing cells than in phosphatidylcholine-containing cells. the decreased rates of spontaneous cholesterol ...19846469983
effect of trichothecenes on growth and intracellular pool size of mycoplasma gallisepticum.the mycotoxin t-2 inhibited the growth of mycoplasma gallisepticum. the growth inhibition was most pronounced with the hydrophobic derivatives t-2 acetate and very little with the hydrophilic t-2 tetraol. the toxin had no effect on the biosynthesis of either protein, dna, rna or complex lipids but markedly reduced the intracellular pool size of soluble low molecular mass precursors. it seems that t-2 acetate, by virtue of its hydrophobic nature, may accumulate within the lipid backbone affecting ...19846479334
two cholesterol pools in acholeplasma laidlawii membranes.cholesterol exchange kinetics between [14c]cholesterol-labeled acholeplasma laidlawii and mycoplasma gallisepticum cells and phosphatidylcholine-cholesterol vesicles followed a biphasic curve, with faster exchange rates for a. laidlawii. the same biphasic curve was obtained with isolated membranes. cholesterol exchange between lipid vesicles and a. laidlawii cells depleted of phospholipids by phospholipase a2, fitted a monophasic linear curve. the data support the hypothesis that the biphasic ch ...19846479337
a comparison of the methods of the european pharmacopoeia for the detection of mycoplasma gallisepticum and mycoplasma synoviae.the methods specified in the european pharmacopoeia for the detection of mycoplasma synoviae and mycoplasma gallisepticum as contaminants of vaccines were compared by investigating the serological responses of chicks inoculated with dilutions of mycoplasma cultures, these cultures being titrated in parallel in vitro. inoculation by the intrathoracic route proved to be as sensitive as, or more sensitive than the other methods and was of similar sensitivity to the in vitro titrations for both agen ...19846480614
infectious sinusitis in turkeys at ibadan, nigeria.thirty out of 70 imported broad-breasted white turkeys with severe sinusitis were both culturally and serologically positive for mycoplasma gallisepticum. infectious sinusitis due to m. gallisepticum was therefore diagnosed. a low mortality of 5.7% of the total flock was recorded. this appears to be the first published report on m. gallisepticum isolation in turkeys in nigeria.19846487193
an epornitic of mycoplasma gallisepticum in turkeys.a major epornitic of mycoplasma gallisepticum occurred in the monroe, north carolina, area between january and june of 1983. the outbreak involved 304,000 turkeys of various ages, which were slaughtered in the eradication program at a cost of more than $550,000 to growers and poultry companies. an infected peafowl was the likely source of infection on the first farm. traffic between farms by growers and company personnel was theorized to be the means of further spread.19846487195
resistance of chickens immunized against mycoplasma gallisepticum is mediated by bursal dependent lymphoid cells.newly hatched chickens were significantly protected against challenge by the virulent s6 strain of mycoplasma gallisepticum after vaccination with the ts 100 mutant. removal of the thymus did not abolish the protective effect of the vaccine, but removal of the bursa of fabricius did. the results suggest that the resistance induced by vaccine is mediated by the bursal-dependent lymphoid cells.19846495612
early stages in the interaction between mycoplasma gallisepticum and the chick trachea, as related to pathogenicity and immunogenicity.mycoplasma strains, which occur naturally or as the result of laboratory manipulation, differ markedly in biological properties such as pathogenicity, infectivity, transmissibility, and immunogenicity. these properties are clinical expressions of a series of complex interactions between the mycoplasma organisms and the host. we have focused on the early interactions occurring at the level of the tracheal mucosa, with the intent of identifying mycoplasma gallisepticum strains possessing a combina ...19846511325
utilization of temperature-sensitive mutants of mycoplasma gallisepticum to prevent air sac infections.three stable temperature-sensitive (ts) mutants were obtained by treating the s6 strain of mycoplasma gallisepticum with 50 micrograms/ml of nitrosoguanidine. these mutants were morphologically and serologically indistinguishable from the parent s6 strain. mutants ts 37 and ts 102 were apathogenic, and ts 100 was moderately pathogenic to chickens when inoculated directly into the air sac. to turkeys, ts 37 remained apathogenic, ts 102 was slightly pathogenic, and ts 100 was highly pathogenic, in ...19846511327
uptake and transbilayer distribution of phosphatidylcholines in mycoplasma gallisepticum and their effect on cell morphology.mycoplasma gallisepticum cells grown in a serum-free medium incorporated large amounts of egg-phosphatidylcholine (egg-pc), dioleoylphosphatidylcholine (dopc) or dipalmitoylphosphatidylcholine (dppc) added to the growth medium. egg-pc and dopc were incorporated at a high rate and to a large extent and were modified by the organisms, whereas dppc was incorporated at a lower rate and to a lesser extent and was not modified by the cells. the lactoperoxidase-mediated radioiodination applied to study ...19846511357
vaccination of turkeys against air-sac infection with a temperature-sensitive mutant of mycoplasma gallisepticum.turkeys were vaccinated with temperature-sensitive (ts) mutants of mycoplasma gallisepticum (mg) to determine pathogenicity and immunogenicity. ts 37 was apathogenic yet immunogenic to turkeys, ts 100 was highly pathogenic, and ts 102 was slightly pathogenic and nonimmunogenic. five or 7 weeks after intranasal vaccination of turkeys with the ts 37 mutant, a highly statistically significant resistance against intra-air-sac challenge with the s6 strain of mg was observed.19846525130
bacterins and vaccines for the control of mycoplasma gallisepticum.the preferred method for the control of mycoplasma gallisepticum is eradication. unfortunately, the advent of multiple-age farms for poultry production has made eradication impractical after the organism has been introduced. live vaccination with the f strain of m. gallisepticum during the rearing period has been used to prevent egg production losses. more recently, an inactivated oil emulsion bacterin has become available commercially. vaccine and bacterin offer protection against egg productio ...19846548986
temperature-sensitive mutants of mycoplasma gallisepticum.mycoplasma gallisepticum (mg) s6 strain was treated with nitrosoguanidine to obtain temperature-sensitive mutants. of the 101 colonies screened, 4 were found to be temperature sensitive. these mutants and the wild type organisms were serologically and morphologically identical. three of the 4 mutants failed to produce air sac lesions when inoculated directly into air sacs of the chicken.19846699219
kinetics of cholesterol and phospholipid exchange between mycoplasma gallisepticum cells and lipid vesicles. alterations in membrane cholesterol and protein content.the kinetics of exchange of radiolabeled cholesterol and phospholipids between intact mycoplasma gallisepticum cells and unilamellar lipid vesicles were investigated over a wide range of cholesterol/phospholipid molar ratio. the change in cholesterol/phospholipid molar ratio was achieved by adapting the sterol-requiring m. gallisepticum to grow in cholesterol-poor media, providing cells with decreased unesterified cholesterol content. at least 90% of the cholesterol molecules in unsealed m. gall ...19846706945
distribution and movement of sterols with different side chain structures between the two leaflets of the membrane bilayer of mycoplasma cells.mycoplasma gallisepticum was adapted to grow with delta 5-sterols modified in the aliphatic side chain, and stopped-flow kinetic measurements of filipin association were made to estimate the sterol distribution between the two leaflets of the membrane. cholesterol derivatives with unsaturated side chains (desmosterol, cis- and trans-22-dehydrocholesterol, and cholesta-5,22e,24-trien-3 beta-ol) or an alkyl substituent (beta-sitosterol) were predominantly (86-94%) localized in the outer leaflet of ...19846706946
evaluation of inactivated mycoplasma gallisepticum oil-emulsion bacterins for protection against airsacculitis in broilers.broiler chicks were vaccinated subcutaneously in the neck at various ages with a single 0.5-ml dose of beta-propiolactone-inactivated mycoplasma gallisepticum (mg) oil-emulsion bacterin. four weeks later, vaccinated and control chicks were placed in cold environmental cabinets, infected with infectious bronchitis virus intratracheally, and 2 days later challenged by aerosol exposure to live mg broth culture. all chicks were killed 21 days later and scored postmortem for the rate and severity of ...19846721795
correlation of titer, preservation method, and storage of mycoplasma gallisepticum f strain and the immune response in chickens.the f strain of mycoplasma gallisepticum (mg) was used either fresh or after lyophilization or freezing at -60 c to vaccinate young leghorn chickens. vaccine stored either frozen or lyophilized for 22 months was also used. each vaccine preparation was given at dosages ranging from 10(5) to 10(9) colony-forming units/ml. all dosage levels of mg significantly (p less than 0.05) reduced air-sac lesion scores after aerosol challenge with the r strain of mg at 6 weeks postvaccination, regardless of t ...19846721801
evaluation of the microagglutination test in the diagnosis of mycoplasma gallisepticum infection in chickens.the sensitivity and specificity of the microagglutination (ma), serum-plate-agglutination (sp), and hemagglutination-inhibition (hi) test for mycoplasma gallisepticum (mg) were compared in groups of chickens infected with mg, m. synoviae, or pasteurella multocida or inoculated with bacterins prepared from staphylococcus aureus or erysipelothrix rhusiopathiae. of the three tests evaluated, the hi test had the highest specificity, but it was the least sensitive. both the ma and sp tests were more ...19846721803
transferred humoral immunity in chickens to mycoplasma gallisepticum.progeny chicks of mycoplasma gallisepticum (mg)-infected and mg-free white leghorns were used to evaluate the protective effects of maternal antibodies against aerosol challenge with the virulent r strain of mg at 3, 7, or 14 days of age. interference by maternal antibodies with day-1 vaccination with the f strain of mg was also studied. in another trial, 8, 4, or 2 ml of high- or low-titered antiserum was given to 20-day-old commercial white leghorn chicks. protection was measured in terms of a ...19846721806
evaluation of attenuated strains of mycoplasma gallisepticum as vaccines in young chickens.five trials were conducted to evaluate the virulence and the vaccination efficacy of the f, r, s6, and a5969 strains of mycoplasma gallisepticum (mg) at different in vitro passage levels. vaccination was done by eye-drop or aerosol, and efficacy was evaluated in terms of air-sac lesions after aerosol challenge with the r strain of mg. continuing medium passage of these strains of mg resulted in gradual attenuation. aerosol vaccination with highly attenuated mg at 21 days of age was more effectiv ...19846721807
mycoplasma gallisepticum vaccination: effects on egg transmission and egg production.the effects of mycoplasma gallisepticum (mg) vaccination on egg transmission of mg and egg production were evaluated. leghorn hens vaccinated with live mg (strain f), with strain f plus mg bacterin, with one dose of mg bacterin, or with two doses of mg bacterin all transmitted mg through the egg at a significantly lower level than unvaccinated controls. hens vaccinated with two doses of mg bacterin had the longest lag before detectable transmission of mg through the egg. all vaccinated groups we ...19846743175
mycoplasma challenge studies in budgerigars (melopsittacus undulatus) and upper respiratory condition that resulted in 20% mortality in a flock of yellow-naped amazon parrots was apparently caused by a concomitant infection of mycoplasmas and bacteria. mycoplasma gallisepticum (mg), m. iowae, and an unidentified mycoplasma were isolated from the affected parrots. budgerigars were experimentally infected with a parrot strain of mg designated mg(p) 1669 as well as with the r strain of mg and the f10-2 strain of m. synoviae (ms). air-sac lesions were evident in all gr ...19846743176
experimental studies on turkey coryza.disease with severe respiratory symptoms, nasal discharge, swelling of sinuses, conjunctivitis with foamy discharge and mortality has been observed in turkey flocks in israel. of the pathogenic agents isolated from field cases, three, paramyxovirus, yucaipa (yucaipa virus), alcaligenes faecalis (a. faecalis) and mycoplasma gallisepticum (mg) were used to infect turkey poults, singly or in combination, in our attempt to reproduce the field disease symptoms. yucaipa virus alone caused mild symptom ...198418766831
the minimum inhibitory concentration of kitasamycin, tylosin and tiamulin for mycoplasma gallisepticum and their protective effect on infected chicks.the minimum inhibitory concentration (m.i.c.) of kitasamycin, tylosin and tiamulin for mycoplasma gallisepticum (mg) were compared with 10(6), 10(4), and 10(2) cfu/ml of the organisms with the drug incorporated in mycoplasma agar. the lowest m.i.c. was obtained with tiamulin and the highest with kitasamycin and, in general, the m.i.c.'s were directly influenced by the concentration of mycoplasmas. chick embryos at 19 days of incubation were infected with mg and the hatched infected chicks were u ...198418766833
microcomputer-assisted morphometric analysis of airsacculitis caused by mycoplasma gallisepticum in immunised and nonimmunised chickens.inflammation caused by inoculation of mycoplasma gallisepticum (mg) into the air sacs was compared in chickens previously exposed by intramuscular injection of mg with that produced in nonimmunised chickens. air sacs from chickens inoculated with frey's media, from those receiving only intramuscular injections of mg, and from nonimmunised non-challenged birds were included in the evaluations. the airsacculitis produced in immunised chickens was more severe at 48 hours post-challenge infection th ...198418766867
[avian mycoplasmosis: comparative study of the plate agglutination test, haemagglutination inhibition test and metabolic inhibition test for detection of antibody against mycoplasma gallisepticum].this study was performed with the use of the mg/s6 strain of mycoplasma gallisepticum, reference sera, sera from vaccinated chickens (given at inactivated vaccine) and sera from infected turkeys in the field. titres of antibody detected were well correlated for the three tests. however, the plate agglutination test (pat) allowed the earliest detection, and metabolic inhibition test (mit) was as sensitive and specific as the haemagglutination inhibition test (hit). mit allowed a good repeatabilit ...198418766885
a correlative in vivo study of the surface morphology and colonisation of the chicken trachea infected by mycoplasma gallisepticum strains r and f.the pathogenic processes occurring in the chicken trachea as the result of infection by mycoplasma gallisepticum were followed at frequent intervals over a 2-week period after introduction of the organism into the trachea. a correlation was made between changes in the surface morphology of the trachea, as seen by the scanning electron microscope, and mycoplasma colonisation of the upper respiratory tract, as evaluated in isolation studies. effects of the clinical status of the birds were indicat ...198318766781
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