The anatomy of two functional types of mechanoreceptive 'free' nerve-ending in the head skin of
            Xenopus
            embryos

The structure of the two functional types of ‘free’ nerve-ending in the head skin of late Xenopus embryos has been examined by horseradish peroxidase staining through their cells in the trigeminal ganglion and by electron microscopy. Type I neurites are identified as the ‘movement’ detectors by their purely homolateral innervation. They have many fine branches between the superficial skin cells, bearing numerous large varicosities. Type II neurites cross the midline to innervate both sides of the head as do the ‘rapid transient’ detectors found by physiology. They have a few fairly straight branches between the skin cell layers with few elongated varicosities.

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Co-culture of type I and type II pneumocytes as a model of alveolar epithelium

10.1101/2021.03.08.434368 ◽

2021 ◽

Author(s):

Oliver Brookes ◽

Sonja Boland ◽

René Lai Kuen ◽

Armelle Baeza-Squiban

Keyword(s):

Cell Lines ◽

Barrier Function ◽

Single Cells ◽

Light And Electron Microscopy ◽

Alveolar Epithelium ◽

Type I ◽

Apical Surface ◽

Type Ii ◽

Cell Layers ◽

Distal Lung

AbstractThe epithelial tissues of the distal lung are continuously exposed to inhaled air, and are of research interest in studying respiratory exposure to both hazardous and therapeutic materials. Pharmaco-toxicological research depends on the development of sophisticated models of the alveolar epithelium, which better represent the different cell types present in the native lung and interactions between them.We developed an air-liquid interface (ALI) model of the alveolar epithelium which incorporates cell lines representative of both type I (NCI-H441) and type II (hAELVi) epithelial cells. We compared morphology of single cells and the structure of cell layers of the two lines using light and electron microscopy. Working both in monotypic cultures and cocultures, we measured barrier function by trans-epithelial electrical resistance (TEER), and demonstrated that barrier properties can be maintained for 30 days. We created a mathematical model of TEER development over time based on these data in order to make inferences about the interactions occurring in these culture systems. We assessed expression of a panel of relevant genes that play important roles in barrier function and differentiation.The coculture model was observed to form a stable barrier akin to that seen in hAELVi, while expressing surfactant protein C, and having a profile of expression of claudins and aquaporins appropriate for the distal lung. We described cavities which arise within stratified cell layers in NCI-H441 and cocultured cells, and present evidence that these cavities represent an aberrant apical surface. In summary, our results support the coculture of these two cell lines to produce a model which better represents the breadth of functions seen in native alveolar epithelium.

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Enhancement of outer cell layers of a methanotrophic bacterium using uranyl acetate en bloc

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102456 ◽

1988 ◽

Vol 46 ◽

pp. 74-75

Author(s):

K. Putzer ◽

T.A. Fassel ◽

C.C. Remsen

Keyword(s):

Uranyl Acetate ◽

Outer Cell ◽

Type I ◽

Type Ii ◽

En Bloc ◽

Wall Structures ◽

Intracytoplasmic Membranes ◽

Cell Layers ◽

Ethanol Series ◽

Autotrophic Microorganisms

Obligate methanotrophic bacteria are autotrophic microorganisms capable of oxidizing methane to supply both their carbon and energy requirements. Methanotrophs are placed in one of two groups based on certain biochemical features and the arrangement of intracytoplasmic membranes (ICM). Type I methanotrophs contain ICM arranged as bundles of disc-like vessicles in the interior of the cell, while Type II methanotrophs display paired peripheral ICM. The organism used in this study, Methylosinus trichosporium OB3b, is a Type II methanotroph and has a capsular structure surrounding the cell as well as several complex cell wall structures described as cup-like, filamentous, and spike-shaped. This study examines the external surface of M. trichosporium OB3b following en bloc staining with uranyl acetate.Cells were harvested in mid-log phase, fixed in 0.5% glutaraldehyde and postfixed in 1% OsO4. Cells were enrobed in 4% agar prior to dehydration in a graded ethanol series.

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Co-culture of type I and type II pneumocytes as a model of alveolar epithelium

PLoS ONE ◽

10.1371/journal.pone.0248798 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0248798

Author(s):

Oliver Brookes ◽

Sonja Boland ◽

René Lai Kuen ◽

Dorian Miremont ◽

Jamileh Movassat ◽

...

Keyword(s):

Cell Lines ◽

Barrier Function ◽

Single Cells ◽

Light And Electron Microscopy ◽

Alveolar Epithelium ◽

Type I ◽

Apical Surface ◽

Type Ii ◽

Cell Layers ◽

Distal Lung

The epithelial tissues of the distal lung are continuously exposed to inhaled air, and are of research interest in studying respiratory exposure to both hazardous and therapeutic materials. Pharmaco-toxicological research depends on the development of sophisticated models of the alveolar epithelium, which better represent the different cell types present in the native lung and interactions between them. We developed an air-liquid interface (ALI) model of the alveolar epithelium which incorporates cell lines which bear features of type I (hAELVi) and type II (NCI-H441) epithelial cells. We compared morphology of single cells and the structure of cell layers of the two lines using light and electron microscopy. Working both in monotypic cultures and cocultures, we measured barrier function by trans-epithelial electrical resistance (TEER), and demonstrated that barrier properties can be maintained for 30 days. We created a mathematical model of TEER development over time based on these data in order to make inferences about the interactions occurring in these culture systems. We assessed expression of a panel of relevant genes that play important roles in barrier function and differentiation. The coculture model was observed to form a stable barrier akin to that seen in hAELVi, while expressing surfactant protein C, and having a profile of expression of claudins and aquaporins appropriate for the distal lung. We described cavities which arise within stratified cell layers in NCI-H441 and cocultured cells, and present evidence that these cavities represent an aberrant apical surface. In summary, our results support the coculture of these two cell lines to produce a model which better represents the breadth of functions seen in native alveolar epithelium.

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Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067522 ◽

1970 ◽

Vol 28 ◽

pp. 106-107 ◽

Cited By ~ 1

Author(s):

Ronald S. Weinstein ◽

N. Scott McNutt

Keyword(s):

New Zealand ◽

General Hospital ◽

Massachusetts General Hospital ◽

Type I ◽

Type Ii ◽

Collaborative Effort ◽

Temperature And Pressure ◽

The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111367 ◽

1984 ◽

Vol 42 ◽

pp. 250-251

Author(s):

G. D. Gagne ◽

M. F. Miller ◽

D. A. Peterson

Keyword(s):

Endoplasmic Reticulum ◽

Experimental Infection ◽

Uranyl Acetate ◽

Type I ◽

Cellular Injury ◽

Type Ii ◽

Tubular Structures ◽

Type Iii ◽

Type Iv ◽

Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

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Comparative surface and ultrastructural views of methylotrophic bacteria by TEM, STEM, SE, and freeze-etch electron microscopy.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128274 ◽

1987 ◽

Vol 45 ◽

pp. 792-793

Author(s):

T.A. Fassel ◽

M.J. Schaller ◽

M.E. Lidstrom ◽

C.C. Remsen

Keyword(s):

Cytoplasmic Membrane ◽

Structural Features ◽

Methylotrophic Bacteria ◽

Type I ◽

Type Ii ◽

Membrane Complex ◽

Oxidation Of Methane ◽

Methane Oxidizing Bacteria ◽

Wall Structures ◽

Methylomonas Albus

Methylotrophic bacteria play an Important role in the environment in the oxidation of methane and methanol. Extensive intracytoplasmic membranes (ICM) have been associated with the oxidation processes in methylotrophs and chemolithotrophic bacteria. Classification on the basis of ICM arrangement distinguishes 2 types of methylotrophs. Bundles or vesicular stacks of ICM located away from the cytoplasmic membrane and extending into the cytoplasm are present in Type I methylotrophs. In Type II methylotrophs, the ICM form pairs of peripheral membranes located parallel to the cytoplasmic membrane. Complex cell wall structures of tightly packed cup-shaped subunits have been described in strains of marine and freshwater phototrophic sulfur bacteria and several strains of methane oxidizing bacteria. We examined the ultrastructure of the methylotrophs with particular view of the ICM and surface structural features, between representatives of the Type I Methylomonas albus (BG8), and Type II Methylosinus trichosporium (OB-36).

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