Surface mucopolysaccharides of Treponema pallidum

The viscous mucoid fluid that accumulates within syphilitic lesions may be due to breakdown of host tissue during infection, or may be synthesized by Treponema pallidum. Experiments were performed to investigate the acidic mucopolysaccharides that occur at the surface of T. pallidum (Nichols strain). These mucopolysaccharides were demonstrated by reaction with acidified bovine serum albumin and by agglutination with wheat germ agglutinin and soybean agglutinin. The polycations ruthenium red and toluidine blue influenced treponemal survival. Concentrations of both compounds at 200 mug/ml inhibited survival, whereas concentrations at 0.1mug/ml enhanced survival. The mucopolysaccharide concentration within the mucoid fluid that accumulates during intratesticular infection was determined by reaction with acidified bovine serum albumin; it ranged from 10,000 mug/ml to less than 8 mug/ml. The addition of this mucoid fluid to treponemal suspensions resulted in differing effects on T. pallidum survival. Some preparations were inhibitory, and others were stimulatory. Commercial preparations of hyaluronic acid and chondroitin sulfate at 400, 200, 100, and 50 mug/ml were detrimental to treponemal survival. The organisms exhibited pronounced clumping in the presence of the higher concentrations of hyaluronic acid. These clumps of treponemes were comprised of mucopolysaccharides as shown by acidified bovine serum albumin and toluidine blue reactions and by hyaluronidase degradation. Results are discussed in terms of the derivation and potential role of acidic mucopolysaccharides at the surface of T. pallidum.

Inhibitory effects of extracellular products from oral bacteria on human fibroblasts and stimulated lymphocytes

Extracellular products of 12 strains of Streptococcus mutans and 5 additional species of oral bacteria were analyzed for their ability to inhibit proliferation of fibroblastoid cells (HeLa and AV3) and blast transformation of human peripheral blood lymphocytes obtained from normal individuals. Products from S. mutans strains AHT and BHT, Streptococcus intermedius, and Actinomyces viscosus inhibited [3H]thymidine uptake by fibroblastoid cells and phytohemagglutinin-stimulated lymphocytes. Products from S. mutans E49, Streptococcus salivarius, and Actinomyces naeslundii inhibited blast transformation of human lymphocytes but did not significantly inhibit the growth of fibroblastoid cells. Preparations from S. intermedius gave the greatest inhibitory activity against both target cell types; initial characterization of this preparation suggested a single factor active in both assays, in that the heat lability and Sephadex G-200 elution profile were similar for the inhibitory activity seen with the two cell types. The molecular weight of the inhibitor, estimated by gel filtration on Sephadex G-200 and Ultragel AcA34, was approximately 160,000. The results strongly suggest that oral bacteria produce heat-labile substances that interfere with fibroblast proliferation and alter the lymphocytic immunological response.

Lyssavirus infection of muscle spindles and motor end plates in striated muscle of hamsters

Immunofluorescent, light, and electron microscopy were used to document lyssavirus infection of muscle spindles and motor end plates. Virus particles were seen in the narrow intercellular space between sensory nerve endings and intrafusal muscle fibers; they were also observed budding from intracellular and plasma membranes of the latter. Involvement of motor nerves and motor end plates could only be demonstrated by electron microscopy. In nature, rabies virus invasion of the peripheral nervous system must involve centripetal spread across these junctions.

Morphologic evidence for retrovirus production by epithelial cells derived from a human testicular tumor metastasis

Ultrastructural examination of primary and subcultured epithelial cells established in vitro from an abdominal metastasis of a human testicular tumor revealed particles with the morphology of retroviruses. These structures, found only after extensive scanning of the cells, were observed budding from microvilli and from the outer cell membrane and as extracellular particles. Production of these virus particles was stimulated by the incubation of cells in culture medium containing 5-iodo-2'-deoxyuridine and dexamethasone.

Are yeasts in vaginal smears intracellular or extracellular?

Using light microscopic cytodiagnosis the only thing that can be said about the position of the yeast cells in relation to the epithelial cells is that the epithelial cells and the parasite are very close to one another. It is not possible to say whether both elements are only temporarily projected above one another or in direct contact. This question can only be answered unequivocally with the aid of the electron microscope. It is possible to verify that the yeast cells, despite their size, are able to invade intact epithelial cells and are capable of reproduction within these same cells.

Infectious mononucleosis. Epstein-Barr-virus shedding in saliva and the oropharynx

In an examination of excretion patterns of Epstein-Barr virus in 104 throat washings from 20 patients with infectious mononucleosis we found that three persons regularly shed virus from the second week through the third month after onset; 15 demonstrated intermittent excretion over three months, and in two cases, no virus was detected. In oral secretions, the virus appeared to be located extracellularly. Transforming activity was demonstrated in aliquots after centrifugation and filtration, in a sample in which cells were disrupted before filtration, and in specimens after two years' storage. Multiple oropharyngeal sites were examined for presence of the virus. In one patient, virus was regularly demonstrated in throat washings and saliva; swabs from Stensen's duct orifices yielded virus in three of four cases. Demonstration of virus in these oropharyngeal specimens explains increased transmissibility in age groups in which salivary exchange is high.

Surface localization of virus production on a glucocorticoid-stimulated oncornavirus-producing mouse mammary tumor cell line by scanning electron microscopy

A chronically infected continuous mouse mammary tumor cell line containing virus particles of type B morphology, free of contaminating type C virions, has been grown in tissue culture. These cells were treated with dexamethasone, a synthetic glucocorticoid, a potent stimulator of mouse mammary tumor virus expression. Surfaces of untreated and dexamethasone-treated cells were investigated by scanning electron microscopy. Untreated cells demonstrated a moderate expression of mouse mammary tumor virus (80 particles/cell) distributed diffusely over the cell surface. However, virions on dexamethasone-treated cells were localized in clusters of 100 to greater than 2000 virus particles, often with more than one cluster per cell. Dexamethasone-treated cells typically showed a 10-fold increase in cell-associated virus over untreated cells. Concentrated extracellular fluids from untreated and dexamethasone-treated cultures were quantitated for free virus. Dexamethasone-treated culture fluids demonstrated a similar 10-fold increase of extracellular particles, in contrast to untreated cultures. This increase in virus particles on the cell surfaces as well as in the extracellular fluids supports the theory that dexamethasone has a stimulatory effect on viral replication, not just on the release of budding particles. The ultrastructure of budding mouse mammary tumor virus during dexamethasone stimulation, determined by scanning and transmission electron microscopy, and the significance of such an in vitro system for viral immunodiagnosis are discussed.

Ultrastructural and associated studies on experimental mastitis in the mouse produced by three strains of streptococcus

Ultrastructural studies were made on mastitis produced experimentally in the mouse by 3 different strains of streptococcus. The first strain of Str. agalactiae produced cellular changes detectable by electron microscopy as early as 6 hours after inoculation and at 48 hours alterations to secretory epithelium, lumenal contents and subepithelial tissue were very evident; later samplings showed more advanced changes. Cocci were seen in the lumens and within secretory cells; at later stages they showed degenerative changes themselves. A second strain of Str. agalactiae produced similar general changes; milk protein masses were common in the lumens, and rod-shaped crystals were observed. Cocci were seen free in the lumens, in lumenal macrophages, within secretory cells and, in later stages, in the subepithelial tissue. The possibility of their penetrating the epithelium either through the epithelial cell substance or through the intercellular space is discussed. Studies with a strain of Str. uberis indicated a lower level of pathogenicity but electron microscopy showed a variety of cellular changes. It was clear from comparative studies, including the use of heat-killed cocci, that very large numbers of bacteria must be present in a given specimen for their identification in ultrathin sections of mammary gland.

Serial ultrathin sectioning demonstrating the intracellularity of T. Pallidum. An electron microscopic study

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