Microscopic colonial morphology of an enterococcal L form

1968 ◽  
Vol 14 (6) ◽  
pp. 746-747
Author(s):  
Robert J. Anderson
Keyword(s):  
Direct Observation ◽  
Streptococcus Faecalis ◽  
Slide Preparation ◽  
Solid Media ◽  
Colonial Morphology ◽  
Permanent Slide

A possible reversion cycle from the L colony to the parent coccus in Streptococcus faecalis var. zymogenes on solid media is postulated. The peripheral large bodies of the L colony appeared to give rise to mycelial-like structures which extended away from the L colony and terminated in fragmenting cocci. This phenomenon was observed on a permanent slide preparation only and not from direct observation of growing organisms.

Rapid method for permanent slide preparation of colonies in soft agar cultures

1986 ◽  
Vol 4 (5) ◽  
pp. 368-374 ◽  
Author(s):  
Jazbieh Moezzi ◽  
Francis Ali-Osman ◽  
Martin J. Murphy
Keyword(s):  
Rapid Method ◽  
Soft Agar ◽  
Slide Preparation ◽  
Permanent Slide

The morphology of induced wall-defective variants of Streptococcus faecalis as studied by light and electron microscopy

1971 ◽  
Vol 17 (3) ◽  
pp. 365-371 ◽  
Author(s):  
R. V. Marraro ◽  
R. M. Pfister ◽  
M. S. Rheins ◽  
I. Kapetanovic
Keyword(s):  
Light And Electron Microscopy ◽  
Test Organism ◽  
Cellular Level ◽  
Induction Medium ◽  
Streptococcus Faecalis ◽  
Thin Sections ◽  
Single Colony ◽  
Egg Morphology ◽  
Colonial Morphology ◽  
Fresh Isolate

Study by light microscopy of induced wall-defective variants of Streptococcus faecalis was undertaken to examine the sequential development of these forms during a 36-day period. Particularly noted were the early cell wall deficient forms observed at 36 h which appear as "cartwheels." Evolution of these forms through the various stages of the granular-appearing colonies to the classical "fried egg" morphology is described. A similar developmental pattern was observed with both a prototype of the test organism as well as with a fresh isolate from the genitourinary tract of a patient.Colonies of induced wall-defective variants of S. faecalis grown on an induction medium were examined in the electron microscope by use of the technique of ultrathin sectioning. This study was undertaken to examine, at the cellular level, the colonial morphology of these variants and to describe differences existing in specified areas of the colony. Longitudinal thin sections of the induced wall-defective colonies were prepared from three levels of the colonies as they related to the medium surface: supraagar surface; subagar surface; and deep subagar. Examination of the thin sections offers evidence that the bacterial population in a single colony is morphologically heterogeneous.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

Direct Observation of the Diffusionless β → β + ω Transformation in Titanium Alloys

1971 ◽  
Vol 29 ◽  
pp. 122-123
Author(s):  
N. E. Paton ◽  
D. de Fontaine ◽  
J. C. Williams
Keyword(s):  
Electron Microscope ◽  
Titanium Alloys ◽  
Direct Observation ◽  
Dark Field ◽  
X Ray Diffraction ◽  
Resistivity Measurements ◽  
Selected Area Electron Diffraction ◽  
Ti Alloys ◽  
Thin Foils ◽  
Field Device

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.

A New 1000kv Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 100-101
Author(s):  
J.L. Williams ◽  
K. Heathcote ◽  
E.J. Greer
Keyword(s):  
Electron Microscope ◽  
Direct Observation ◽  
High Voltage ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Specimen Thickness ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
Dynamic Experiments ◽  
Conventional Instrument

High Voltage Electron Microscope already offers exciting experimental possibilities to Biologists and Materials Scientists because the increased specimen thickness allows direct observation of three dimensional structure and dynamic experiments on effectively bulk specimens. This microscope is designed to give maximum accessibility and space in the specimen region for the special stages which are required. At the same time it provides an ease of operation similar to a conventional instrument.

Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem

1976 ◽  
Vol 34 ◽  
pp. 54-55
Author(s):  
Karen S. Howard ◽  
H. D. Braymer ◽  
M. D. Socolofsky ◽  
S. A. Milligan
Keyword(s):  
Cell Wall ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Morphological Comparison ◽  
Small Areas ◽  
Solid Media ◽  
Thin Sectioning ◽  
X Cells ◽  
Mutant Cells ◽  
Isolated Cell

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).

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