Nucleic Acid Content of Pleuropneumonialike Organisms From Human Sources

Abstract

Early studies with the pleuropneumonialike organisms concerned themselves with methods of isolation of these organisms and their possible relationship to various pathological conditions. More recently, investigators have included studies of nutritional requirements and some metabolic activities. While these microorganisms can be cultivated in artificial media, their smallest elements are capable of passing through filters designed to retain bacteria. The small size, slow growth, and sluggish metabolic activity, as well as their fragility and poor staining qualities have helped distinguish the pleuropneumonialike organisms from bacteria. The findings that some bacteria undergo variation to an L phase, which may resemble morphologically and culturally the pleuropneumonialike organisms, stress the need for more detailed information about these microorganisms. The present study concerns itself with the determination of the nucleic acid content and composition of a strain of pleuropneumonialike organisms isolated from the human urethra.

Comparative Physiology of Pleuropneumonia-Like and L-Type Organisms

“…This organism contains adenine, guanine, cytosine, and uracil in molar proportions of 10.0, 17.5, 16.8, and 11.2, respectively. The purine-pyrimidine ratio was 0.98 (59). Schlieren photographs of the sedimentation pattern of RNA from M. gallisepticum 5969 revealed 17S, 38S, 58S, 76S, 84S, and 117S ribosomal particles (70).…”

“…Although accurate determination of these values as percentage of dry weight for comparative purposes is not possible, it can be estimated that total nucleic acid in this strain represents 12 to 15% of the dry weight. M. hominis 07 contains 4 to 5% nucleic acid (59), whereas in 31. gallisepticum 5969 total nucleic acid represents 12% of the dry weight of the organisms (70). Recently, Langenfeld and Smith (51) determined the nucleic acid phosphorus content of 13 strains of Mycoplasma of varied origin (avian, human, caprine, bovine, tissue culture, sewage).…”

“…RNA is found to the extent of 3 to 10% in the two types of organisms, with larger amounts being found in the L organisms (43,59,70,79,162). In both M1ycoplasma (43, 59) and L organisms (43), RNA increases rapidly during the early logarithmic phase and then declines rapidly, reaching its lowest level during the stationary phase.…”

“…Kandler et al (43) found 3 mg of nucleic acid per mg of protein nitrogen during the logarithmic phase for L 52, derived from P. vulgaris. As with the Mycoplasma (43,59), there was a reduction of nucleic acid in the stationary phase, due to reduction of ribonucleic acid (RNA). Weibull (162), working with L 9, derived from P. mirabilis, found a total nucleic acid content of 14 to 19% of the dry weight.…”

“…The variation in total nucleic acid content can be accounted for not only by strain variation but also by the age of the organisms used for analyses. Since RNA content increases during the early logarithmic phase and then declines rapidly (43,59), cells harvested in the stationary phase would be low in RNA and, thus, total nucleic acid. Cellular disruption during handling of preparations would liberate RNA into the nonsedimentable fraction as reported by Plackett (85), who found that freezing and thawing of cells of .…”