Fine structure of pleuropneumonia-like organisms in pure culture and in infected tissue culture cells

Evidence for the presence of a human saprophytic oral bacterium, Mycoplasma faucium, in the skin lesions of a psoriatic patient

Psoriasis is currently regarded a mixed autoimmune and autoinflammatory disease. This report describes for the first time the detection of a saprophytic, human oral Tenericutes species, Mycoplasma faucium, in the skin lesions of a patient presenting initially guttate and later plaque psoriasis. An unusual finding in standard histopathology investigation consisted of round and oval thinly stained or unstained, possibly intracellular structures, apparently directly pressing on keratinocyte nuclei of the psoriatic stratum spinosum. In ultrastructural study, wall-less bacteria were present intracellularly in the keratinocytes, mainly of the psoriatic stratum spinosum, and extracellularly in the upper dermis of the psoriatic lesions. M. faucium was consistently detected and identified in the psoriatic skin by general Tenericutes polymerase chain reaction and sequencing in two biopsies performed 31 months apart. This case raises new questions concerning the pathogenesis of psoriasis and its accepted autoimmune/autoinflammatory nature.

Cancer cells arise from bacteria

Background

The origin of cancer cells is the most fundamental yet unresolved problem in cancer research. Cancer cells are thought to be transformed from the normal cells. However, recent studies reveal that the primary cancer cells (PCCs) for cancer initiation and secondary cancer cells (SCCs) for cancer progression are formed in but not transformed from the senescent normal and cancer cells, respectively. Nevertheless, the cellular mechanism of PCCs/SCCs formation is unclear. Here, based on the evidences (1) the nascent PCCs/SCCs are small and organelle-less resembling bacteria; (2) our finding that the cyanobacterium TDX16 acquires its algal host DNA and turns into a new alga TDX16-DE by de novo organelle biogenesis, and (3) PCCs/SCCs formations share striking similarities with TDX16 development and transition, we propose the bacterial origin of cancer cells (BOCC).

Presentation of the hypothesis

The intracellular bacteria take up the DNAs of the senescent/necrotic normal cells/PCCs and then develop into PCCs/SCCs by hybridizing the acquired DNAs with their own ones and expressing the hybrid genomes.

Testing the hypothesis

BOCC can be confirmed by testing BOCC-based predictions, such as normal cells with no intracellular bacteria can not "transform" into cancer cells in any conditions.

Implications of the hypothesis

According to BOCC theory: (1) cancer cells are new single-celled eukaryotes, which is why the hallmarks of cancer are mostly the characteristics of protists; (2) genetic changes and instabilities are not the causes, but the consequences of cancer cell formation; and (3) the common role of carcinogens, infectious agents and relating factors is inducing or related to cellular senescence rather than mutations. Therefore, BOCC theory provides new rationale and direction for cancer research, prevention and therapy.

Control of Pleuropneumonia-like Organisms in Cell Culture

Mammalian cell culture systems were maintained free of mycoplasmas by using a 3-day agar plate test as a weekly routine to monitor the conditions of the cells. If contaminated cell cultures were found, they were discarded and replaced from a pleuropneumonia-like organism (PPLO)-free cell bank. PPLO-free lines were established by treatment with various antibiotics. The KB cell line was freed of mycoplasmas by treatment for 1 week with a mixture of chlortetracycline, kanamycin, and chloramphenicol. L-929 cells were cleared of contamination with either spectinomycin or tylosin, and a synovial cell line was cleared with lincomycin or tylosin. Each cell line, after eradication of the contaminant, was stored in liquid nitrogen. A number of agents were tested to determine minimal inhibitory concentration against three known and three unidentified mycoplasmas. Chlortetracycline and tetracycline were found to be highly active against all strains, whereas tylosin, spectinomycin, and lincomycin, though less active, were equally useful because of their low toxicity against cells. Kanamycin was highly active against three strains, but inactive at high levels against the KB cell contaminants. A disc plate test was used to check isolated cell contaminants for sensitivity to various agents.

CYTOPATHIC EFFECT OF THE ATYPICAL PNEUMONIA ORGANISM IN CULTURES OF HUMAN TISSUE

Eaton, Monroe D. (Harvard Medical School, Boston, Mass.), Ann E. Farnham, Jeana D. Levinthal, and Anthony R. Scala. Cytopathic effect of the atypical pneumonia organism in cultures of human tissue. J. Bacteriol. 84:1330-1337. 1962.-Three strains of the atypical pneumonia agent were adapted to grow in continuous cell cultures of human amnion or human embryonic lung, with production of initial increased acidity followed by destruction of the cells. Evidence is presented that cytopathic effects of the organism were associated with intracellular growth and formation of microcolonies. Clumps of organisms stained specifically with fluorescein-labeled antibody, and showed distinctive tinctorial reactions with the May Grünwald-Giemsa stain. The cytopathic effect was prevented by fresh serum from a rabbit immunized with an egg-passage strain of the atypical pneumonia agent. Heating the immune serum to 56 C for 30 min abolished the neutralizing effect. The significance of heat-labile serum constituents in killing or inhibition of mycoplasma is discussed.

Do mycoplasmas cause human cancer?

A linkage between mycoplasmas and malignancy was mainly proposed in the 1960s when human-associated mycoplasmas were becoming of interest given the novel characterization of the human respiratory pathogen Mycoplasma pneumoniae. Associations with leukemia and other malignancies, however, were largely ascribed to tissue-culture contamination, which is now recognized as a significant potential problem in molecular biology circles. A few epidemiological studies, however, continue to raise concern over such a linkage. As well, in vitro data have demonstrated the potential for some mycoplasmas to induce karyotypic changes and malignant transformation during chronic tissue-culture infestation. As cellular and molecular mechanisms for such transformation become studied, a resurgence of interest in this area is inevitable. A role for mycoplasmas in malignancy of any sort is conjectural, but there remains a need to continue with focussed epidemiological and laboratory investigations.Key words: mycoplasma, cancer, oncogenesis, leukemia.

Incidence and detection of pleuropneumonia-like organisms in cell cultures by fluorescent antibody and cultural procedures

Barile, Michael F. (National Institutes of Health, Bethesda, Md.), Walter F. Malizia, and Donald B. Riggs. Incidence and detection of pleuropneumonia-like organisms in cell cultures by fluorescent antibody and cultural procedures. J. Bacteriol. 84:130-136. 1962-A total of 102 tissue-cell cultures from 17 separate laboratories was examined for pleuropneumonia-like organisms (PPLO) by the fluorescent antibody and cultural procedures. PPLO were isolated from 48 of the 49 tissue-cell cultures found positive for PPLO by the fluorescent antibody procedure, and results of the two procedures agreed in 101 of the 102 (99%) cases. PPLO were isolated from none of 10 primary-cell cultures prepared from six animal species and from 48 of 92 (52%) continuous-cell cultures prepared from eight animal species. Cells grown in media containing antibiotics were more frequently contaminated with PPLO (72%) than cells grown in antibiotic-free media (7%). Cultures (91%) from tissue-culture-producing laboratories and cultures (76%) used for propagation of microorganisms were contaminated with PPLO, although none used for tissue-culture metabolic studies was contaminated. In addition, our findings support the view that PPLO contamination of cell cultures is probably owing to bacterial contaminants which revert to L forms in the presence of antibiotics.

Synchronized division of avian pleuropneumonialike organisms

Kelton, William H. (University of Massachusetts, Amherst). Synchronized division of avian pleuropneumonia-like organisms. J. Bacteriol. 83:948-955. 1962.-Evidence indicates that phosphate-buffered 0.85% saline (pH 7.0) is toxic when used for diluting cultures of pleuropneumonia-like organisms (PPLO). A technique for picking single PPLO colonies and streaking on agar medium is described. Growth curves of eight strains of PPLO of avian origin are described. Strain S-6 showed a typical growth curve. The other strains presented the lag and logarithmic phases of growth, followed by a rapid decline in viable numbers and peaks of growth later. Additional studies showed that growth was logarithmic in young cultures of all strains. Synchronization of division of two avian strains of PPLO appeared to have been induced by starvation for horse serum. Studies of small populations of PPLO were also made. The results of these experiments, along with the logarithmic growth, favor binary fission as the mode of reproduction.

Metabolism of animal cells infected with mycoplasma

Powelson, Dorothy M. (Stanford Research Institute, Menlo Park, Calif.). Metabolism of animal cells infected with mycoplasma. J. Bacteriol. 82:288-297. 1961.-The effect of pleuropneumonia-like organisms (PPLO) upon the metabolism of tissue cultures was tested by comparing the assimilation and accumulation of the amino acids in the medium during growth and maintenance of monolayers of mouse fibroblasts (L strain) and human bone marrow cells (Mox). This preliminary study indicates that PPLO do alter the amino acid metabolism of animal cells. The observed changes in metabolic patterns shown by the infected fibroblast cultures did not mirror the metabolic patterns of the PPLO in the medium alone. Different strains of animal cells showed different responses to one PPLO strain, and different strains of PPLO caused different responses in one strain of animal cells. The PPLO did not grow in the tissue culture medium (no. 199 plus 2% horse serum and 20 to 40 units of penicillin/ml) nor in spent culture fluids and rapidly died off at 37 C but survived for months at 4 C. The altered metabolism of the infected tissue cultures appeared to reflect a true host-parasite interaction.

CYTOPATHOGENIC MYCOPLASMAS ASSOCIATED WITH TWO HUMAN TUMORS. II. MORPHOLOGICAL ASPECTS

Hummeler, K. (The Children's Hospital of Philadelphia, Philadelphia, Pa.), D. Armstrong, and N. Tomassini. Cytopathogenic mycoplasmas associated with two human tumors. II. Morphological aspects. J. Bacteriol. 90:511-516. 1965.-Cytopathic effects (CPE) produced in HeLa cell cultures by two strains of mycoplasmas (F-11 and F-12) were studied by light and electron microscopy. CPE, which was marked by cytoplasmic vacuolization, did not appear to depend on intracellular mycoplasma infection. The cytopathogenic mycoplasmas appeared to be similar, both morphologically and in their intra- and extracellular distribution, to noncytopathogenic mycoplasmas previously studied by others. The probability that the CPE is related to depletion of essential nutrients is discussed, and the fine structure of the mycoplasmas is described.

Intracellular location of mycoplasmas in cultured cells demonstrated by immunocytochemistry and electron microscopy

Mycoplasma fermentans (strain 'incognitus') was incubated with HeLa cells for up to 96 h. After 24 h, mycoplasma organisms were demonstrated intracellularly by immunocytochemistry using mule anti-M. fermentans antiserum and gold labelling on ultrathin sections of both Lowicryl K4M and Araldite-embedded HeLa cells, the latter being treated with hydrogen peroxide. The Araldite-embedded cells were fixed with glutaraldehyde and osmium tetroxide in the presence of ruthenium red to stain the mucopolysaccharide surface components of both the procaryotic and eucaryotic cells. Intracellular localization of some M. fermentans organisms was confirmed by exclusion of ruthenium red from their membranes. Various numbers of mycoplasma organisms were seen per cell and occasionally some were within vacuoles, the membranes of which were also unstained by ruthenium red. The PG18 strain of M. fermentans and a strain of M. hominis were also detected intracellularly using similar methodology and homologous mule or rabbit antisera. The occasional presence of both apparently normal and some denser degenerate mycoplasmas in the same cell may indicate gradual degradation by phagolysosomal digestion.

Medium-dependent properties of mycoplasmas

Without a cell wall, the morphology, growth rate, and composition of mycoplasmas are culture media-dependent with variable properties best described as environmentally related. The adaptation of mycoplasmas to either a tissue cell or cell-free culture media, with dependency upon specific animal or plant products for survival, has led to investigations of their human host-related properties. The influence of culture media on the antibiotic sensitivities of mycoplasmas was measured by use of three different broths in two different assay systems. The variable results indicate that the inhibition of mycoplasma protein synthesis or growth may also be host-tissue dependent. The addition of noninhibitory penicillins to different culture media was found to affect the composition and antigenicity of some mycoplasmas. Using the complement fixation test, we found some human sera that were more reactive than rabbit antisera to mycoplasmas cultured in human synovial broth or in myelin-enriched broth. Mycoplasmas cultured in human lung broth and pig lung broth had media-dependent antigenicity. The antigenicity and the growth of mycoplasmas were found to depend on the proteolytic enzymes used to provide the essential peptides in tissue broths. The media-affected mycoplasmas indicate the presence of species-, strain-, and tissue-specific antigen sites that may determine immunopathogenicity in the genetically susceptible host.

Influence of the fusogenic agent polyethylene glycol on attachment of Mycoplasma pneumoniae to other cells

The effect of fusogenic agents on the interaction of Mycoplasma pneumoniae with human lung fibroblasts was evaluated. A 60-s exposure of the fibroblasts to polyethylene glycol (molecular weight 200; 10%) significantly increased attachment of mycoplasmas to the fibroblasts.

Differences in the attachment of Mycoplasma pneumoniae cells and membranes to tracheal epithelium

Hamster trachea organ cultures were exposed to isolated membranes of Mycoplasma pneumoniae, PI 1428. Attachment, monitored by the uptake of tritiated membranes, was relatively insensitive to neuraminidase pretreatment, unlike the attachment of viable cells. Membrane attachment was optimal when explants were incubated with 50 to 100 micrograms of membrane protein per ml in minimal essential medium broth while gently being rotated (1 rpm) in a roller apparatus for 90 to 120 min at 37 degrees C. Saturation of the receptor sites with viable cells failed to inhibit subsequent membrane attachment. Induction of squamous metaplasia by extended cultivation of tracheal explants in a vitamin A-free medium reduced the content of ciliated cells without significantly affecting total cell viability, but did not alter the attachment of M. pneumoniae membranes. Collectively, the data indicate that the mechanism of attachment of M. pneumoniae membranes to respiratory epithelium is distinct from the receptor site-mediated attachment of M. pneumoniae cells.

Ultrastructure of a mycoplasma recovered from the bone marrow in systemic lupus erythematosus

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Mycoplasmas and cell cultures

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The interaction in vitro of Mycoplasma pulmonis with mouse peritoneal macrophages and L-cells

Methods have been devised for establishing infection in vitro of mouse macrophages and fibroblasts with Mycoplasma pulmonis. The mycoplasmas attached to the cells and under appropriate cultural conditions grew into a lawn of microorganisms covering most of the cell surface. The mycoplasmas grew abundantly on fibroblasts cultured in minimal essential medium containing 20% fetal calf serum; supplementation of this medium with heart infusion broth was necessary to obtain similar growth on macrophages. The infection of these cells appeared to be essentially an extracellular process; only rarely were partially degraded mycoplasmas seen with phagocytic vacuoles. The addition to heavily infected macrophage cultures of low concentrations of anti-mycoplasma antibody stimulated rapid, massive phagocytosis of the surface microorganisms. In sharp contrast, the same antiserum had no discernable effect on the mycoplasma-fibroblast relationship. The antibody effect in the macrophage system was apparently a direct opsonic one rather than an indirect result of microbial killing, since the mycoplasmas in macrophage or fibroblast cultures incorporated labelled thymidine into DNA after the addition of antiserum to the medium. The phagocytic event and the subsequent fate of the mycoplasmas were studied in detail after the addition of antibody to the macrophage cultures. Phase-contrast cinemicrophotography revealed membrane ruffles surrounding the surface mycoplasmas and disappearance from view of the organisms; 10-30 min later translucent grapelike clusters were seen in large phagocytic vacuoles. On electronmicroscopic study the surface mycoplasmas were surrounded by pincers-like projections of the macrophage. Numerous mycoplasmas were seen in phagocytic vacuoles; in the early minutes after the addition of antibody the intracellular mycoplasmas appeared normal, but within 2 hr they appeared partially degraded with a central electron-lucent area and electron-opaque deposits at the microbial cell margin. 24 hr after the addition of antiserum, digestion of the mycoplasmas was nearly complete; the cells appeared normal except for large residual bodies composed of amorphous moderately dense material and increased lipid deposits. Degradation of mycoplasmas within macrophages was also studied using infected cultures in which the mycoplasmas, but not the macrophages, had incorporated tritiated thymidine into DNA. The appearance of large amounts of acid-soluble radiolabel after phagocytosis stimulated by antibody confirmed the degradation of the intracellular mycoplasmas.

Fine structure and location of the mycoplasma-like gray lung and rat pneumonia agents in infected mouse lung

The mycoplasma-like gray lung and rat pneumonia agents were indistinguishable in fine structure and location in infected mouse lung. Both agents resembled mycoplasmas in fine structure, being bounded by a 110 A unit membrane which enclosed an internal region of 20 to 30 A branching fibrils and groups of 120 A ribosomes. They differed from mycoplasmas in having an 80 to 90 A electron-lucent space separating the unit membrane from the internal material, and the internal region was bounded by a 30 to 40 A unbranched fibril. In division, the organisms appeared to form a transverse trilayered "division plate." In overall shape, the organisms seemed to be thick circular or oval plates, and they tended to lie in palisade arrangement on cell surfaces. Both agents were free in large numbers in the alveoli and respiratory bronchioles, and on the surface of intro-alveolar mononuclear cells, but were not seemingly associated with lung cells as such. Intracellular organisms were within membrane-bounded inclusions.

Pneumonia due to mycoplasma in gnotobiotic mice. II. Localization of Mycoplasma pulmonis in the lungs of infected gnotobiotic mice by electron microscopy

Organick, Avrum B. (Marquette University School of Medicine, Milwaukee, Wis.), Kenneth A. Siegesmund, and Irving I. Lutsky. Pneumonia due to mycoplasma in gnotobiotic mice. II. Localization of Mycoplasma pulmonis in the lungs of infected gnotobiotic mice by electron microscopy. J. Bacteriol. 92:1164-1176. 1966.-Lesions in lungs of gnotobiotic mice inoculated intranasally with Mycoplasma pulmonis were examined by electron microscopy after osmic acid fixation. At 1 week after infection, mycoplasma cells were found in large numbers in the bronchi at the surface of bronchial epithelial cells and, in smaller numbers, in the alveoli where active phagocytosis by polymorphonuclear leukocytes (PMN) occurred. Cytopathic changes in underlying bronchial epithelial cells, not apparent by light microscopy, were observed. At 3 weeks after infection, mycoplasma cells were rarely seen in the bronchi, and were no longer seen free in the alveolar spaces or within PMN. Lungs examined after glutaraldehyde fixation 1 week after infection confirmed the presence of mycoplasma cells in the alveolar spaces and within phagocytic vacuoles of PMN, but also revealed numerous ring forms within granular pneumocytes. These forms seemed to represent intracytoplasmic developmental stages of M. pulmonis, in which elementary bodies appeared in large numbers.

The interaction of mycoplasmas with mammalian cells. II. Monocytes and lymphocytes

The incubation of mycoplasmas with human peripheral blood buffy coats resulted in the uptake of these microorganisms by more than 50% of the mononuclear cells. Mycoplasmas adhered to the plasma membranes of all leukocytes, most of which developed long cytoplasmic processes not seen in the controls. In human and rat thoracic duct lymph, about 6% of the cells ingested the microorganisms. T(2) phage and thorotrast were taken up by a similar percentage of lymphocytes. On morphological grounds, the cells which were able to take up PPLO's or particles could not be distinguished from the cells which were incapable of this function. Following phagocytosis, neither the cell nor the microorganism showed any morphological alterations over a 3 hr period of observation. The demonstration that a small percentage of "lymphocytes" are able to phagocytose may have pathological and immunological implications.

The interaction of mycoplasmas with mammalian cells. I. HeLa cells, neutrophils, and eosinophils

The ultrastructure of three mycoplasma species, Mycoplasma pneumoniae, Mycoplasma gallisepticum, and Mycoplasma neurolyticum, has been studied in isolated form as well as in HeLa cell cultures and following incubation with human peripheral blood leukocytes. During log growth phase, the organisms could be distinguished from each other on the basis of their fine structure. In mammalian cell cultures, PPLO's appeared to proliferate on the plasma membranes which had markedly increased their surface area by means of long cytoplasmic processes which extended toward and surrounded them. Some of the microorganisms affected in this way may well have lain, not in vacuoles, but at the bottom of crypts. It is suggested that the cytopathogenic effect exerted by PPLO's on some tissue cultures may be attributable to membrane damage. Mycoplasmas adhered to leukocyte plasma membranes in a similar manner. They were avidly phagocytosed by neutrophils and eosinophils with accompanying degranulation of the white cells. It is thus likely that the local inflammatory reaction induced by PPLO's does not differ in essence from that caused by bacteria.

Growth phases of Mycoplasma in liquid media observed with phase-contrast microscope

Razin, Shmuel (University of Connecticut, Storrs), and Benjamin J. Cosenza. Growth phases of Mycoplasma in liquid media observed with phase-contrast microscope. J. Bacteriol. 91:858-869. 1966-Growth of 11 Mycoplasma strains in liquid media was followed by phase-contrast microscopy. A similar pattern of development was common to all strains. Branching filaments, 0.3 to 0.4 mu thick, characterized the early logarithmic phase of growth. The length of the filaments varied according to the strain tested and the growth medium. Addition of oleic acid to the medium induced the formation of very long filaments by M. laidlawii strain B. Upon aging, the filaments were found to break up into chains of coccoid elements. These chains further fragmented to yield shorter chains and single coccoid elements, which characterized the stationary and decline phases of growth. The size of the coccoid elements increased from 0.3 to 0.4 mu, when formed in the filaments, to 0.6 to 0.8 mu after being released from the chains. Further increase in the size of the cells took place at the decline phase of growth, leading to the formation of very large cells reaching a diameter of 10 to 20 mu. However, these large cells had the appearance of empty vesicles and were apparently nonviable as indicated by viable-count experiments.

Fine structure of Haemobartonella muris as compared with Eperythrozoon coccoides and Mycoplasma pulmonis

Tanaka, H. (The Rockefeller University, New York, N.Y.), W. T. Hall, J. B. Sheffield, and D. H. Moore. Fine structure of Haemobartonella muris as compared with Eperythrozoon coccoides and Mycoplasma pulmonis. J. Bacteriol. 90:1735-1749. 1965.-Thin sections of filterable hemolytic anemia agent of rat, now identified as Haemobartonella muris, revealed (i) that the agent is spherical or ellipsoidal and 350 to 700 mmu in size, (ii) that it has a single limiting membrane enclosing granules and some filaments (neither cell wall nor nucleoid was found), and (iii) that it is found preferentially at the surface and sometimes within the cytoplasmic vacuoles of erythrocytes in the circulating blood and bone marrow, and multiplies there through binary fission. No specific structure suggestive of motility was found. From the morphological point of view, Eperythrozoon coccoides was found to be very similar to H. muris, whereas Mycoplasma pulmonis, also covered with a single limiting membrane, differs in its pleomorphism and multiplication. These and some other microorganisms taxonomically between bacteria and viruses were compared morphologically, and their possible classification is discussed.