OCCURENCE OF GLYCOGEN IN INCLUSIONS OF THE PSITTACOSIS-LYMPHOGRANULOMA VENEREUM-TRACHOMA AGENTS

Susceptibility of Chlamydia to antibacterial drugs: test in cell cultures

Concentrations of 20 mug of sulfadiazine or 30 mug of d-cycloserine/ml were found to be suitable for testing the differential susceptibility of Chlamydia trachomatis and C. psittaci to these drugs in cell cultures.

The development of TRIC organisms in cell cultures during multiple infection

The relationship between multiplicity of infection and the yield of organisms and of polysaccharide was studied in BHK 21 cells infected with TRIC organisms. Although an increase in the multiplicity of infection resulted in an increase in the absolute number of organisms per culture, there was a decrease in relation to the number of infecting organisms. The amount of polysaccharide produced was independent of multiplicity of infection; it was not limited by the concentration of glucose in the medium. Polysaccharide leaked from cells and was slowly broken down in the culture medium.

Effect of ionizing irradiation on susceptibility of McCoy cell cultures to Chlamydia trachomatis

The effect of graded doses of irradiation (cobalt-60) on the morphology of McCoy cells was analyzed, and 4,000 to 5,000 r was selected as a satisfactory dose for production of giant cells. The susceptibility of radiation-induced giant cells to chlamydial infection was compared with that of nonirradiated cells by using three strains of Chlamydia trachomatis and one of C. psittaci. Monolayers of giant cells were more susceptible than normal McCoy cells as indicated by (i) greater numbers of inclusions (four- to eightfold) per unit area of monolayer, (ii) larger inclusions (fourfold greater in area), (iii) higher infective titers (1 log or more greater) of harvested cells, and (iv) greater ease of promoting a second cycle of growth. Graded doses of irradiation were applied also to mouse fibroblast (L) cells, and a similar increase in susceptibility to chlamydial infection was noted. It is concluded that giant cells produced by irradiation possess advantages over nonirradiated cells in culture for growth of Chlamydia.

Inapparent respiratory infection of inbred Swiss mice with sulfadiazine-resistant, iodine-negative Chlamydiae

Three chlamydial strains were isolated from the lungs of three different strains of mice that were inbred for over 30 years. These chlamydial strains were resistant to sulfadiazine and did not induce iodine-positive, glycogen-like material in the inclusions of infected L cells which characterizes them as Chlamydia psittaci.

Effect of Interferon and Interferon Inducers on Infections with a Nonviral Intracellular Microorganism, Chlamydia trachomatis

The effect of mouse interferon (IF) on the multiplication of Chlamydia trachomatis (strain MRC-1/G) in homologous (L-929) cell cultures and the effect of the IF inducers Newcastle disease virus (NDV) and polyriboinosinic acid-polyribocytidylic acid complex (poly I:C) on the experimental infection of mice with aerosolized C. trachomatis (strain MoPn) were investigated. Treatment of infected cell cultures with IF reduced the number of cells containing chlamydial inclusions and depressed the yield of chlamydiae as determined by titrations for infectivity. Growth of chlamydiae was reduced when cultures were exposed to IF 6 or 18 hr before infection, and slight reduction of the yield was also detectable in cell cultures treated with IF at early intervals (0 or 4 hr) after chlamydial infection. No effect of IF on penetration of chlamydiae into mouse cells was observed, whether phagocytic cells from peritoneal washings or L-929 cells were used, indicating that the inhibitory effect of IF occurs after chlamydiae enter the host cell. Additional evidence was obtained that a significant effect of IF occurs at an early stage in maturation of the intracellular chlamydiae. In mice exposed repeatedly to NDV aerosols and challenged with aerosolized MoPn 8 hr after the first exposure to NDV, mortality was delayed by 2 to 3 days and lung consolidation was slightly reduced at 3 days after infection. Yields of chlamydiae from lung pools of NDV-treated mice, taken at 3, 6, and 9 days after challenge, were not significantly different from those of controls. Similar results were obtained when mice were challenged with MoPn 8 hr after intranasal injection with 100 μg of poly I:C or 24 hr after intravenous injection with 200 μg of poly I:C. In contrast, administration of 0.2 ml of NDV (10 8.3 plaque-forming units) intravenously 10 hr before or 24 hr after challenge with MoPn accelerated mortality of mice by 2 to 3 days. In all experiments, detectable levels of IF in sera or 20% lung suspensions were found only up to 48 to 72 hr after exposure of mice to IF inducers.

Glycogen metabolism in Chlamydia-infected HeLa-cells

A difference in glycogen metabolism between two strains of Chlamydia agents was observed which can serve as a taxonomic marker to distinguish C. psittaci from C. trachomatis.

Lymphogranuloma venereum. II. Characterization of some recently isolated strains

Five Bedsonia (Chlamydia) isolates from lymphogranuloma venereum (LGV) patients were tested for inclusion type, sulfonamide sensitivity, and mouse virulence. Two matched the classical description of LGV agents. Two were not virulent for mice by the intracerebral route, therefore fitting the description for trachoma-inclusion conjunctivitis agents. One was highly virulent for mice and sulfonamide-resistant, and produced inclusions that did not stain with iodine, all characteristics generally associated with avian bedsoniae. A sixth isolate could not be adequately tested due to poor infective yields. Because of this variety of properties within the Bedsonia group, the term LGV might more appropriately be reserved for clinical disease rather than to describe a particular bedsonial agent.

Transaminase activity and other enzymatic reactions involving pyruvate and glutamate in Chlamydia (psittacosis-trachoma group)

The agents of meningopneumonitis (MN) and of trachoma (TR) purified from chick embryo allantoic fluids and yolk sacs, respectively, were shown to produce CO(2) from the C(1) positions of pyruvate and glutamate, but not from the other carbon atoms. The reaction with pyruvate did not require did not require the addition of cofactors, but was stimulated to a small extent by alpha-lipoic acid and, in the case of TR, also by diphosphothiamine, and nicotinamide adenine dinucleotide (NAD). The reaction of MN with glutamate was greatly stimulated by the addition of NAD and pyruvate, and resulted in the accumulation of alanine. The reaction of TR with glutamate was also greatly enhanced by added NAD, but was not affected by added pyruvate. When eight intermediates of the citric acid cycle were added to MN cells incubated with glutamate-C(14), plus NAD and pyruvate, they reduced to varying degrees the evolution of C(14)O(2). It was shown by chromatography that the C(14) label extended to alpha-ketoglutarate and succinate, but not to fumarate and malate. A net gain in adenosine triphosphate could not be demonstrated in MN cells incubated with combined glutamate, pyruvate, oxaloacetate, and various cofactors. These results furnish additional examples of real or apparent gaps in enzyme sequences in Chlamydia.