The Membrane Skeleton of Pseudomicrothorax

1991 ◽  
Vol 100 (4) ◽  
pp. 707-715 ◽  
Author(s):  
IRM HUTTENLAUCH ◽  
ROBERT K. PECK
Keyword(s):  
Spatial Organization ◽  
Membrane Skeleton ◽  
Basal Bodies ◽  
Structural Elements ◽  
Or Groups ◽  
Positive Immunoreactivity ◽  
Cortical Membranes ◽  
Cytoskeletal Elements

The membrane skeleton, or epiplasm, is part of the structurally complex ciliate cortex. It is thought to have skeletal functions concerning the spatial organization of cortical elements such as the basal bodies. Here we report the biochemical and immunological characterization of some components of the purified epiplasm of Pseudomicrothorax dubius. The epiplasm proteins consist of two quantitatively major groups of proteins, one of 76–80x103Mr, the other of 11–13x103Mr, which appear to be the principal structural elements of the epiplasm, and a series of minor components of 62–18x103Mr. Based upon lectin labeling and glycosidase treatment, some of the latter have been identified as glycoproteins. Using affinity-purified antibodies specific for individual glycoproteins or groups of glycoproteins, we were able to localize them in situ by immunoelectron microscopical methods. This in situ localization demonstrates that the glycosylated epitopes, unlike the glycoresidues of membrane proteins, are distributed throughout the entire epiplasmic layer rather than being restricted to regions adjacent to the cortical membranes. Thus, these proteins represent glycosylated, cytoskeletal elements. At least one of these glycoproteins (Mr 62x103) shows positive immunoreactivity with a monoclonal antibody (Pruss anti-IFA) recognizing most intermediate filament (IF) proteins, indicating that IF proteins might be present in protozoan cytoskeletons.

Identification of proteins associated with microtubule-organizing centres and filaments in the oral apparatus of the ciliate Paramecium tetraurelia

1990 ◽  
Vol 97 (3) ◽  
pp. 553-563
Author(s):  
GUY KERYER ◽  
FRANCINE IFTODE ◽  
MICHEL BORNENS
Keyword(s):  
Monoclonal Antibody ◽  
Spatial Organization ◽  
Buccal Cavity ◽  
Ultrastructural Localization ◽  
Basal Bodies ◽  
Paramecium Tetraurelia ◽  
Single Polypeptide ◽  
Almost All ◽  
Structure And Activity

In an effort to study the assembly of microtubules in ciliates we have isolated the oral apparatus of Paramecium tetraurelia, a major microtubuie-organizing centre (MTOC) and identified several proteins localized in the fibrillar system associated with basal bodies. Using a monoclonal antibody raised against human centrosomes (CTR210) and a polyclonal antibody (OF1) directed against a 87x103Mr protein of the oral apparatus of Tetrahymena, we observed the same decoration of the oral apparatus of Paramecium, both in situ and after isolation. Ultrastructural localization further showed the presence of the antigens in the fibrillar network that forms a layer under almost all the buccal cavity in close apposition to the basal bodies. CTR210 recognized two sets of polypeptides of Mr72 and 80x103, whereas OF1 recognized a single polypeptide of Mr87x103. Only the 80x103Mr polypeptide was also decorated with the monoclonal antibody MPM-2, previously shown to decorate the oral apparatus of Paramecium and known to react with phosphorylated epitopes in a large variety of MTOCs. All the proteins identified with the three antibodies are insoluble at high ionic strength, display several isoforms and apparently belong to the same fibrillar material. The function of this material in the spatial organization, the structure, and activity of the MTOCs is discussed.

Comparison of In Situ and Laboratory Testing for the Characterization of Old Timber Beams before and after Intervention

2010 ◽  
Vol 133-134 ◽  
pp. 1101-1106 ◽  
Author(s):  
Maurizio Piazza ◽  
Mariapaola Riggio ◽  
Roberto Tomasi ◽  
Ivan Giongo
Keyword(s):  
Laboratory Testing ◽  
Mechanical Characterization ◽  
Testing Procedure ◽  
Structural Elements ◽  
Bending Tests ◽  
Before And After ◽  
Strengthening Technique ◽  
And Control

In this paper an investigation campaign, carried out in occasion of the restoration of a timber floor in the Belasi Castle (Trentino, Italy), is reported. In order to validate a testing procedure for the calibration and control of an innovative wood-wood strengthening technique, results of tests performed in situ on the structural elements, in both the original and the repaired condition, have been compared with those obtained in laboratory on some dismantled beams. For the characterization of the material decay, both local mechanical and global vibrational testing have been carried out. For the mechanical characterization of the beams, before and after repair, direct static bending tests have been performed, with distributed loads, on site, and according to standard four-points loading schemes, in laboratory.

scholarly journals Visualization of Respiratory Commensal Bacteria in Context of Their Natural Host Environment

2021 ◽  
Vol 12 ◽  
Author(s):  
Joao P. P. Bonifacio ◽  
Mirco Schmolke
Keyword(s):  
Spatial Organization ◽  
Operational Taxonomic Unit ◽  
The Body ◽  
Commensal Bacteria ◽  
Model Organisms ◽  
Rrna Gene ◽  
Host Environment ◽  
Isolation And Characterization

Commensal microbes are an integral component of mammalian physiology. 16S rRNA gene-specific next generation sequencing from DNA of total organs, swabs or lavages has revolutionized the characterization of bacterial communities in virtually every ecological niche of the body. Culturomics, next allowed the isolation and characterization of commensal bacteria in the lab and the establishment of artificial communities of bacteria, which were eventually reintroduced in model organisms. Spatial organization of microbiota within a given host environment is critical to the physiological or pathological phenotypes provoked by commensal microbiota. In situ hybridization (ISH) is a complementary technique to sequencing and culturing to visualize the presence of individual bacterial operational taxonomic unit (OTUs) in context of the colonized organ. We recently applied highly sensitive in situ RNA hybridization to detection of commensal bacteria in low abundance respiratory tract samples of mice housed under specific pathogen free conditions. This technique allows species-specific detection of living bacteria using RNAScopeTM technology, while preserving the natural environment of the organ. We here provide a detailed step-by-step protocol describing the detection of commensal lung bacteria in respiratory tissue.

The assembly and positioning of cytoskeletal elements in Tetrahymena

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 23-30
Author(s):  
NE Williams ◽  
JE Honts
Keyword(s):  
Membrane Skeleton ◽  
Basal Bodies ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Wild Type ◽  
Conditional Mutant ◽  
Correct Pattern ◽  
Feeding Structure ◽  
Filament Protein ◽  
Cytoskeletal Elements

The oral skeleton of Tetrahymena is a precisely arranged assemblage of basal bodies, microtubule bundles and connecting filaments found associated with the feeding structure in this cell type. Tubulin and filament proteins have been isolated but no actin has been recovered. The conditional mutant NP1 of Tetrahymena thermophila forms a normal oral skeleton at the permissive temperature (28 degrees C), but forms an abnormal one at the restrictive temperature (37 degrees C). Antibodies against tubulin and oral filament protein OF1 were used to visualize the abnormal oral skeleton and stages in its development, and ultrastructural comparisons of abnormal and wild-type oral skeletons were made. It was found that the overall pattern of organization was altered in the mutant, whereas the substructure appeared everywhere to be normal. Studies of cells in which the mutant phenotype was coming to expression revealed that normal basal bodies in the oral skeleton failed to move from the disordered state characteristic of early stages of development into the correct pattern of four organized clusters characteristic of later stages. Together, these results suggest that the lesion in NP1 does not affect cytoskeleton assembly per se, but instead affects a discrete mechanism responsible for the positioning of cytoskeletal elements with respect to each other after they have been formed (meta-assembly). Reasons for suspecting the involvement of the membrane skeleton are presented.

Regional differentiation of the membrane skeleton in Tetrahymena

1987 ◽  
Vol 87 (3) ◽  
pp. 457-463
Author(s):  
N.E. Williams ◽  
J.E. Honts ◽  
R.F. Jaeckel-Williams
Keyword(s):  
Cell Surface ◽  
Cell Shape ◽  
Surface Membrane ◽  
Tetrahymena Pyriformis ◽  
Membrane Skeleton ◽  
Regional Differentiation ◽  
Basal Bodies ◽  
Structural Elements ◽  
Molecular Weights ◽  
Triton X

Antisera have been raised in rabbits against three high molecular weight proteins that are present in Triton X-100-insoluble residues of Tetrahymena pyriformis GL cells. These proteins, called A, B and C, have apparent molecular weights of 235, 135 and 125 (X 10(3)), respectively, in SDS-polyacrylamide gels. The antisera obtained are specific for these proteins, as shown by immunoblotting. Immunolocalization studies are reported that suggest that these proteins are present throughout the epiplasmic layer beneath the cell surface (membrane skeleton). Images obtained with the fluorescence microscope, however, suggest that the membrane skeleton is modified in discrete zones: (1) around somatic basal bodies, (2) within the oral apparatus, (3) in the cytoproct, (4) in contractile vacuole pores, (5) in the fission zone in late division, and (6) at the mating junction in conjugating cells. These regions may represent areas of increased rigidity at the cell surface. The transition from pliable to rigid epiplasm in spatially delimited areas is apparently a recurring theme in cortical morphogenesis in Tetrahymena. Together, the two types of epiplasm probably allow for extensive changes in cell shape while preserving essential relationships between structural elements within the cortex.

A single-cell atlas of mouse lung development

Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Nicholas M. Negretti ◽  
Erin J. Plosa ◽  
John T. Benjamin ◽  
Bryce A. Schuler ◽  
A. Christian Habermann ◽  
...  
Keyword(s):  
Single Cell ◽  
Spatial Organization ◽  
Expression Patterns ◽  
Mesenchymal Cell ◽  
Mouse Lung ◽  
Rna In Situ Hybridization ◽  
And Function ◽  
Parenchymal Cells

ABSTRACT Lung organogenesis requires precise timing and coordination to effect spatial organization and function of the parenchymal cells. To provide a systematic broad-based view of the mechanisms governing the dynamic alterations in parenchymal cells over crucial periods of development, we performed a single-cell RNA-sequencing time-series yielding 102,571 epithelial, endothelial and mesenchymal cells across nine time points from embryonic day 12 to postnatal day 14 in mice. Combining computational fate-likelihood prediction with RNA in situ hybridization and immunofluorescence, we explore lineage relationships during the saccular to alveolar stage transition. The utility of this publicly searchable atlas resource (www.sucrelab.org/lungcells) is exemplified by discoveries of the complexity of type 1 pneumocyte function and characterization of mesenchymal Wnt expression patterns during the saccular and alveolar stages – wherein major expansion of the gas-exchange surface occurs. We provide an integrated view of cellular dynamics in epithelial, endothelial and mesenchymal cell populations during lung organogenesis.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

1993 ◽  
Vol 51 ◽  
pp. 1058-1059
Author(s):  
J. Liu ◽  
M. Pan ◽  
G. E. Spinnler
Keyword(s):  
Supported Catalysts ◽  
Imaging Techniques ◽  
Nano Particles ◽  
Metal Particles ◽  
Shape Structure ◽  
Dynamical Simulations ◽  
Small Metal Particles ◽  
Extract Information

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

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