Electron Micrograph Studies of Two Strains of Pleuropneumonia-like (L) Organisms of Human Derivation

Colonial growth of Mycoplasma gallisepticum observed with the electron microscope

Shifrine, Moshe (University of California, Davis), Jack Pangborn, and Henry E. Adler. Colonial growth of Mycoplasma gallisepticum observed with the electron microscope. J. Bacteriol. 83:187-192. 1962.-Mycoplasma gallisepticum strain S(6) was grown on collodion film on solid medium. Samples were removed every few hours, fixed, washed, shadowed, and observed with the electron microscope. Three distinct forms of growth were observed: elementary cells (hexagonally shaped), platycytes, and exoblasts. A tentative mode of growth was postulated. The significance of the angular morphology to the relation between mycoplasmas and L-forms of bacteria is discussed.

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.

Properties of Mycoplasma hominis 4330

Mycoplasma strain 4330, one of the earliest strains of pleuropneumonia-like organisms to be isolated from man in the United States, has been found to resemble M. hominis type 1 by serological methods (the growth inhibition and latex agglutination tests). The results of earlier serological studies indicated a similarity between the Campo and 4330 strains which was not detected by use of the cultures currently available. Strain 4330 differs from strains of Mycoplasma recently isolated from man by producing acid from a variety of carbohydrates. This acquisition of biochemical properties may be the result of hundreds of transfers on artificial media during a period of more than a quarter of a century. Identification of the strain was deemed advisable, since two different cultures and a mixed culture existed under the designation "4330." The extraneous organisms were found to be closely related to M. laidlawii by their biological and serological properties.

Phase-contrast and electron microscopy of murine strains of Mycoplasma

Nelson, John B. (The Rockefeller University, New York, N.Y.), and Michael J. Lyons. Phase-contrast and electron microscopy of murine strains of Mycoplasma. J. Bacteriol. 90:1750-1763. 1965.-Two strains of Mycoplasma pulmonis (associated with infectious catarrh) on examination in fluid culture (20% horse serum-bouillon) by phase microscopy were highly pleomorphic, with many bacilliform elements and fewer coccoid ones. Motility, characterized by gliding of rods and spinning of spherical forms, was observed through the 9th subculture of one strain and the 15th of the second. Motile elements were not seen in later transfers and pleomorphism was reduced. One strain of M. neurolyticum (associated with conjunctivitis and encephalitis) was much less pleomorphic and showed neither bacilliform elements nor motility at any time. When examined by negative-contrast electron microscopy, organisms of this strain were found to have an average diameter of 0.7 mu and to possess a concentrated peripheral layer of cytoplasm and a central mass which may represent the cells' nuclear equivalent. The latter feature was not prominent in spherical forms of M. pulmonis. These cells, when observed after 48 hr of culture, showed evidence of the generation of new progeny cells in their central area. The filamentous or bacilliform cells of M. pulmonis were frequently serpentine in appearance, 2.0 to 3.0 mu in length and 80 to 250 mmu in width. They appeared to generate new cells from terminal buds from which outpouchings initially developed. Older cells, in the stationary phase, showed evidence of undergoing multipolar germination. Microtubules, about 60 mmu wide, were found in association with most filamentous cells from 48-hr cultures; fragments of membrane, studded with closely packed ribosomelike particles, were also found. There was no evidence of flagella or any specialized structure that could account for the observed motility of the organisms.

Electron microscope studies of pleuropneumonia like organisms isolated from man and chickens

Images

Electron micrographs made from L forms of Proteus and two human strains of pleuropneumonia-like organisms

Images