Search PubMed⌕ Search

Biomedical subjects

R P WILLIAMS

Publications and source records attributed to R P WILLIAMS.

At least 19 recordsLinked to original sources
PubMed1965

FORMATION OF SPHEROPLASTS FROM BACILLUS ANTHRACIS.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Tex.), and Robert P. Williams. Formation of spheroplasts from Bacillus anthracis. J. Bacteriol. 89:1128-1133. 1965.-Spheroplasts were prepared from Bacillus anthracis by combined treatment with lysozyme and glycine. Glycine, at a final concentration of 3%, was added to cultures of B. anthracis in nutrient broth that had grown at 37 C for 16 to 18 hr under 50% CO(2). After additional incubation under CO(2) for 2 hr, lysozyme, at the appropriate concentration (50 to 100 mug/ml), and sucrose, to a concentration of 15%, were added, and incubation was continued for 2 to 6 hr in CO(2). At the end of this period, incubation in CO(2) was discontinued. Spheroplasts formed after incubation in air for 6 to 12 hr. Lysozyme alone exhibited the same effect when added at much higher concentrations (500 to 2,000 mug/ml) to cultures growing under CO(2). No spheroplasts formed when cultures were treated with glycine alone. Treatment with lysozyme was more effective on smooth strains than rough. Cells from young cultures were more susceptible to lysozyme than older cells. CO(2) apparently was essential for formation of spheroplasts from B. anthracis.

Bacillus anthracis↗
PubMed1964

CULTURE OF THE CYTOPATHIC AREA SURROUNDING VIRULENT CELLS OF BACILLUS ANTHRACIS IN MOUSE SPLEEN.

Roth, Ivan L. (Baylor University College of Medicine, Houston, Tex.), and Robert P. Williams. Nature of the cytopathic area surrounding virulent cells of Bacillus anthracis in mouse spleen. J. Bacteriol. 88:523-530. 1964.-Virulent anthrax bacilli in splenic tissue of mice were seen by electron microscopy to be surrounded by a clear zone that was designated the cytopathic area. Previous experiments did not establish the nature of the area. In the present experiments, virulent anthrax bacilli were grown in a system enriched with CO(2). The bacilli were capsulated and retained the capsule after they were killed by autoclaving. When grown without CO(2), these virulent bacilli were not capsulated. Also used was an avirulent strain of Bacillus anthracis that did not form capsules in either the presence or absence of CO(2). Mice were inoculated intravenously with suspensions containing 5 x 10(8) per 0.5 ml of (i) living or (ii) killed, capsulated virulent bacilli; (iii) killed, noncapsulated virulent bacilli; and (iv) living, avirulent bacilli. Bacteria were found in the spleen 1 hr after injection. Electron microscopy revealed that both living and dead, capsulated virulent bacilli were surrounded by a clear area. No clear area was found around killed, noncapsulated virulent bacilli. Clear areas were never seen around avirulent bacilli. Light microscopy of smears prepared from splenic tissue and stained for the presence of bacterial capsules corroborated the electron microscopic findings. These results established that the cytopathic area surrounding virulent bacilli was capsule.

Animals↗
PubMed1963

GROWTH OF CELLULAR FORMS IN CULTURES OF CHROMATIN BODIES ISOLATED FROM BACILLUS MEGATERIUM.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Texas) and Robert P. Williams. Growth of cellular forms in cultures of chromatin bodies isolated from Bacillus megaterium. J. Bacteriol. 85:623-627. 1963.-Chromatin bodies isolated from old cultures of Bacillus megaterium were capable of growing into protoplastlike cells when cultured in broth enriched with horse serum, yeast extract, adenosine triphosphate, and penicillin. A tendency toward formation of rod forms of bacteria was observed in such cultures. Omission of penicillin from the medium resulted in development of short bacterial forms. In 3 of 29 experiments, actual bacillary forms indistinguishable from the parent B. megaterium organism were recovered. Culture of the chromatin bodies in plain nutrient broth did not produce any growth. Inoculation on serum-enriched agar medium of a culture of chromatin bodies, after they had begun multiplication in serum-enriched broth, resulted in development of large bodies characteristic of L forms. Ability of chromatin bodies to grow was not affected by heating for 2 hr at 80 C or by sonic treatment for up to 25 min. The possible role of such resistant chromatin bodies in the latency and persistence of infectious diseases was discussed.

Bacillus↗
PubMed1963

PREPARATION OF SPHEROPLASTS FROM VIBRIO COMMA.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Texas), and Robert P. Williams. Preparation of spheroplasts from Vibrio comma. J. Bacteriol. 85:838-841. 1963.-Spheroplasts were prepared from several strains of Vibrio comma by lysozyme treatment combined with freezing and thawing of the organisms. The optimal concentration of lysozyme was 50 mug/ml, although some spheroplasts formed at a concentration of 10 mug/ml. Higher concentrations (200 mug/ml) caused lysis of cells along with spheroplast formation. Treatment was carried out in broth cultures containing 15% sucrose, and if the osmotic tension was lowered the spheroplasts lysed. Some motile, spherical cells were present in every preparation. Addition of 3% glycine to broth cultures resulted in rapid transformation of the vibrios into large, spherical bodies. However, these were actively motile, and were not sensitive to a lower osmotic tension. Therefore, they could not be considered as spheroplasts.

Bacteriological Techniques↗
PubMed1962

Cytological observations on the chromatin bodies of two Bacillus species.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Tex.) and Robert P. Williams. Cytological observations on the chromatin bodies of two Bacillus species. J. Bacteriol. 83:1112-1118. 1962.-The nature of the chromatin bodies in Bacillus anthracis and B. megaterium has been studied intracellularly as well as after isolation from the bacilli. Preparations were examined by phase-contrast microscopy in the living state and by acid-Giemsa and Feulgen staining. In cells from young cultures, chromatin bodies occupy a continuous, long, central area in the bacteria. As the cells mature, the bodies lose their continuity and divide into two halves. In cells grown for 24 hr or longer, the chromatin bodies become more complex, and appear as multiple, spherical, interconnected constellations. Nuclear staining reveals that only the peripheral area, whether in cells from young or older cultures, takes up the stain, leaving a clear, central core. Discrete chromatin bodies are liberated from cells grown for longer periods after disintegration of the bacterial cell wall. These discrete bodies have been isolated from whole bacteria by treating washed, buffered saline suspensions of old cells with high concentrations of lysozyme followed by digestion with purified pancreatic lipase. The isolated chromatin bodies retain the same structure and appearance as inside the cells and show the same staining characteristics. Observations suggest that the chromatin bodies are discrete and circumscribed in nondividing, resting-phase bacteria.

Animals↗
PubMed1962

Cytological changes in aging bacterial cultures.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Texas) and Robert P. Williams. Cytological changes in aging bacterial cultures. J. Bacteriol. 84:340-344. 1962.-Morphological changes occurring in aging broth and agar cultures of Bacillus anthracis were observed with the phase-contrast microscope. In 4 to 5 days, in liquid culture, cells lost their normal shape and become fusiform or spherical. Chromatin bodies were clearly visible inside the cells at this time. Spontaneous conversion into protoplast-like, spherical cells was observed on the 6th or 7th day. These cells were sensitive to osmotic changes, but could be preserved by the addition of sucrose to the medium. Budding and atypical multicellular forms also were observed at this stage. In agar cultures, the conversion into spherical forms was observed with more regularity; the presence of sucrose in the medium favored the process. In very late stages of growth, the spherical cells disintegrated into conglomerated masses of cellular debris with the discrete chromatin bodies enmeshed in them. At this stage, secondary colonies appeared, superimposed on the primary ones, and on transfer to suitable medium gave rise to unstable L colonies.

Agar↗