Evaluation of whole cell fixation methods for the analysis of nanoscale surface features of Yersinia pestis KIM

2016 ◽  
Vol 263 (3) ◽  
pp. 260-267 ◽  
Author(s):  
C. WANG ◽  
C.E. STANCIU ◽  
C.J. EHRHARDT ◽  
V.K. YADAVALLI
Keyword(s):  
Yersinia Pestis ◽  
Whole Cell ◽  
Surface Features ◽  
Fixation Methods ◽  
Cell Fixation

scholarly journals Biogenesis of the Fraction 1 Capsule and Analysis of the Ultrastructure of Yersinia pestis

2008 ◽  
Vol 190 (9) ◽  
pp. 3381-3385 ◽  
Author(s):  
Lisa M. Runco ◽  
Selina Myrczek ◽  
James B. Bliska ◽  
David G. Thanassi
Keyword(s):  
Yersinia Pestis ◽  
Host Recognition ◽  
Surface Features ◽  
Bacterial Surface

ABSTRACT Analysis of a Yersinia pestis Δcaf1A mutant demonstrated that the Caf1A usher is required for the assembly and secretion of the fraction 1 capsule. The capsule assembled into thin fibrils and denser aggregates on the bacterial surface. Pilus-like fibers were also detected on the surface of Y. pestis. The capsule occasionally coated these fibers, suggesting how the capsule may cloak surface features to prevent host recognition.

Comparison of cell fixation methods of induced sputum specimens: An immunocytochemical analysis

2006 ◽  
Vol 308 (1-2) ◽  
pp. 36-42 ◽  
Author(s):  
Julie St-Laurent ◽  
Marie-Eve Boulay ◽  
Philippe Prince ◽  
Elyse Bissonnette ◽  
Louis-Philippe Boulet
Keyword(s):  
Induced Sputum ◽  
Immunocytochemical Analysis ◽  
Fixation Methods ◽  
Cell Fixation

scholarly journals Dictyostelium Cell Fixation: Two Simple Tricks

2020 ◽  
Vol 3 (3) ◽  
pp. 47
Author(s):  
Michael Koonce ◽  
Irina Tikhonenko ◽  
Ralph Gräf
Keyword(s):  
Dictyostelium Cell ◽  
Spatial Relationships ◽  
Fixation Methods ◽  
Cytoskeletal System ◽  
Cell Fixation ◽  
Cell Centrifugation

We share two simple modifications to enhance the fixation and imaging of relatively small, motile, and rounded model cells. These include cell centrifugation and the addition of trace amounts of glutaraldehyde to existing fixation methods. Though they need to be carefully considered in each context, they have been useful to our studies of the spatial relationships of the microtubule cytoskeletal system.

Plague and Plague Vaccines

2021 ◽  
Author(s):  
Khrystyna Hrynkevych ◽  
Heinz-Josef Schmitt
Keyword(s):  
Yersinia Pestis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Subunit Vaccines ◽  
Gram Negative ◽  
Whole Cell ◽  
Negative Bacillus ◽  
Gram Negative Bacillus ◽  
The Usa ◽  
Repeated Dosing

Plague is a zoonosis caused by the Gram-negative bacillus, Yersinia pestis, a member of the Enterobacteriaceae family. Madagascar, the Democratic Republic of Congo and Peru are still considered highly endemic for plague; however, the bacterium also exists in some regions in Asia and the USA. First symptoms occur 1 to 7 days after exposure. There are three clinical forms of plague: bubonic, pneumonic, and septicemic plague. Transmitted as an aerosol, Y. pestis has been developed as a biological weapon. There are adjuvanted whole-cell vaccines which need repeated dosing, and which are highly reactogenic; subunit vaccines are in development.

Comparison of three cell fixation methods for high content analysis assays utilizing quantum dots

2008 ◽  
Vol 232 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Y. WILLIAMS ◽  
S. BYRNE ◽  
M. BASHIR ◽  
A. DAVIES ◽  
Á. WHELAN ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Content Analysis ◽  
Fixation Methods ◽  
High Content Analysis ◽  
Cell Fixation

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

HVEM Analysis of Microfilament Patterns in The Margins of Tissue Cells

1980 ◽  
Vol 38 ◽  
pp. 808-811
Author(s):  
Carol Allen
Keyword(s):  
Cell Movement ◽  
Cell Spreading ◽  
Living Cells ◽  
Tissue Cell ◽  
Large Sample Size ◽  
Cell Periphery ◽  
Whole Cell ◽  
Critical Point Drying ◽  
Lamellar Region ◽  
Tissue Cells

When provided with a suitable solid substrate, tissue cells undergo a rapid conversion from the spherical form expressed in suspension culture to a characteristic flattened morphology. As a result of this conversion, called cell spreading, the cell nucleus and organelles come to occupy a central region of “deep cytoplasm” which slopes steeply into a peripheral “lamellar” region less than 1 pm thick at its outer edge and generally free of cell organelles. Cell spreading is accomplished by a continuous outward repositioning of the lamellar margins. Cell translocation on the substrate results when the activity of the lamellae on one side of the cell become dominant. When this occurs, the cell is “polarized” and moves in the direction of the “leading lamellae”. Careful analysis of tissue cell locomotion by time-lapse microphotography (1) has shown that the deformational movements of the leading lamellae occur in a repeating cycle of advance and retreat in the direction of cell movement and that the rate of such deformations are positively correlated with the speed of cell movement. In the present study, the physical basis for these movements of the cell margin has been examined by comparative light microscopy of living cells with whole-mount electron microscopy of fixed cells. Ultrastructural observations were made on tissue cells grown on Formvar-coated grids, fixed with glutaraldehyde, further processed by critical-point drying, and then photographed in the High Voltage Electron Microscope. This processing and imaging system maintains the 3-dimensional organization of the whole cell, the relationship of the cell to the substrate, and affords a large sample size which facilitates quantitative analysis. Comparative analysis of film records of living cells with the whole-cell micrographs revealed that specific patterns of microfilament organization consistently accompany recognizable stages of lamellar formation and movement. The margins of spreading cells and the leading lamellae of locomoting cells showed a similar pattern of MF repositionings (Figs. 1-4). These results will be discussed in terms of a working model for the mechanics of lamellar motility which includes the following major features: (a) lamellar protrusion results when an intracellular force is exerted at a locally weak area of the cell periphery; (b) the association of cortical MFs with one another determines the local resistance to this force; (c) where MF-to-MF association is weak, the cell periphery expands and some cortical MFs are dragged passively forward; (d) contact of the expanded area with the substrate then triggers the lateral association and reorientation of these cortical MFs into MF bundles parallel to the direction of the expansion; and (e) an active interaction between these MF bundles associated with the cortex of the expanded lamellae and the cortical MFs which remained in the sub-lamellar region then pulls the latter MFs forward toward the expanded area. Thus, the advance of the cell periphery on the substrate occurs in two stages: a passive phase in which some cortical MFs are dragged outward by the force acting to expand the cell periphery, and an active phase in which additional cortical MFs are pulled forward by interaction with the first set. Subsequent interactions between peripheral microfilament bundles and filaments in the deeper cytoplasm could then transmit the advance gained by lamellar expansion to the bulk of the cytoplasm.

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