The translaminal fibrils of the human amnion basement membrane

1989 ◽  
Vol 94 (2) ◽  
pp. 307-318
Author(s):  
S. Campbell ◽  
T.D. Allen ◽  
B.B. Moser ◽  
J.D. Aplin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Basal Lamina ◽  
Ammonium Hydroxide ◽  
Apical Surface ◽  
Lamina Densa ◽  
Transmission Electron ◽  
Extraction Pattern ◽  
Stromal Matrix

The organisation of extracellular matrix beneath the human amniotic epithelium was investigated in order that the co-ordinate synthesis of basal lamina and stroma by these cells could be better understood. Transmission electron microscopy of intact tissue confirmed that stromal matrix fibrils are located between the cell surface and the basal lamina, and also penetrate the lamina. The distribution of the supralaminal fibrils and their association with the lamina was further investigated by scanning electron microscopy (SEM) after removal of the overlying epithelium. Five complementary procedures were used to remove the cells from the underlying lamina. Trypsin-EDTA treatment caused the epithelial cells to retract or detach from the lamina. SDS or ammonium hydroxide was used to extract the epithelium, which was then removed by physical shearing. Transmission electron microscopy (TEM) confirmed that the lamina densa and supralaminal fibres were present after extraction by these agents. Incubation in CHAPS, a zwiterionic detergent, did not remove the epithelium but permitted exposure of the basal lamina by mechanical scoring. Extraction with boric acid followed by osmium tetroxide produced epithelial disruption and revealed the lamina and stroma in different areas. Although the extraction pattern was different in each case, all of the five methods confirmed that individual fibrils and fibril bundles are present on the apical surface of, and enter, the lamina densa. Examination of the stromal surface of the basal lamina after fracture revealed fibrils passing from the stroma into the lamina densa. We therefore suggest that, in this tissue, newly synthesised stromal matrix components appear in an assembled fibrillar form between the basal cell surface and the basal lamina before becoming associated with the sublaminal stroma.

Spatial and temporal variation in the structure of the basal lamina in embryonic grasshopper limbs during pioneer neurone outgrowth

Development ◽  
1989 ◽  
Vol 106 (1) ◽  
pp. 185-194 ◽  
Author(s):  
H. Anderson ◽  
R.P. Tucker
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Temporal Variation ◽  
Basal Lamina ◽  
Spatial And Temporal Variation ◽  
Transmission Electron

The pioneer neurones of the embryonic grasshopper limb use the basal lamina underlying the limb ectoderm as a substratum over which to grow from the periphery to the CNS (Anderson & Tucker, 1988). In this paper we use transmission electron microscopy to describe the structure of this substratum before, during, and after the time of axon navigation. The organization of the basal lamina varies considerably in different regions and at different times of development of the embryonic limbs, and is unlike that of the fully developed limb at the time of hatching. We suggest that this spatial and temporal variation could play a role in regulating the direction of outgrowth of pioneer neurones.

Transmission electron microscopy (TEM) of equine conceptuses at 14 and 16 days of gestation

2010 ◽  
Vol 22 (2) ◽  
pp. 405 ◽  
Author(s):  
Ingrid Walter ◽  
Waltraud Tschulenk ◽  
Sven Budik ◽  
Christine Aurich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Specific Cell ◽  
Fluid Uptake ◽  
Embryonic Disc ◽  
Transmission Electron ◽  
Cellular Junctions ◽  
Endodermal Cells ◽  
Specific Cell Surface

The present study gives a detailed ultrastructural description of equine conceptuses at Day 14 (n = 2) and Day 16 (n = 3) after ovulation. Whereas on Day 14 only primitive structures were seen, on Day 16 neurulation and formation of mesodermal somites had taken place. The ectoderm of the embryo itself and the surrounding trophoblast ectodermal cells were characterised by specific cell surface differentiations. At the embryonic ectodermal cell surface (14 and 16 days) remarkable protruded and fused cytoplasmic projections were seen, typically associated with macropinocytotic events involved in macromolecule and fluid uptake. This finding adds an important point to the expansion mode of the hypotone equine conceptus, which is characterised by ‘uphill’ fluid uptake. Numerous microvilli and coated endocytotic pits at the apical trophoblast membrane emphasised its absorptive character. Endodermal cells were arranged loosely with only apically located cellular junctions leaving large intercellular compartments. At the border of the embryonic disc apoptotic cells were regularly observed indicating high remodelling activities in this area. Conspicuous blister-like structures between ectoderm and mesoderm were seen in the trilaminar part of Day-14 and -16 conceptuses. These were strictly circumscribed despite not being sealed by cellular junctions between germinal layers. It is possible that these blisters are involved in embryo positioning; however, further studies are needed to verify this.

Ultrastructural observations of the tegument of Postorchigenes gymnesicus (Digenea: Lecithodendriidae)

1996 ◽  
Vol 70 (1) ◽  
pp. 13-19 ◽  
Author(s):  
J.R. Ferrer ◽  
M. Gracenea ◽  
M. Trullols ◽  
O. Gonzalez-Moreno
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Protein Content ◽  
Basal Lamina ◽  
Apical Membrane ◽  
General Body ◽  
Body Regions ◽  
Transmission Electron ◽  
Direct Association

AbstractThe tegument of Postorchigenes gymnesicus has been studied by scanning and transmission electron microscopy. The general body tegument is spinous and contains mitochondria, biconcave disc-shaped vesicles bounded by an unitary membrane and displaying a protein content, and scarce spherical bodies. The tegument covering specialized body regions is aspinous. Few vesicles were evident in the tegument covering the suckers and oesophagus, being more abundant in the metraterm and cirrus where the tegument is thicker. Laurer's canal has a thick tegument with sparse vesicles, mostly arranged close to the apical membrane. A direct association was evident between the basal lamina underlying the spines and the muscular subtegumental fibres, suggesting a motile character for the spine.

scholarly journals Light and transmission electron microscopy of generalized dystrophic epidermolysis bullosa (Pasini's albopapuloid subtype)

2012 ◽  
Vol 87 (2) ◽  
pp. 285-287
Author(s):  
Hiram Larangeira de Almeida Jr ◽  
Lísia Nudelmann ◽  
Nara Moreira Rocha ◽  
Luis Antonio Suita de Castro
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Female Patient ◽  
Epidermolysis Bullosa ◽  
White Female ◽  
Lamina Densa ◽  
Dystrophic Epidermolysis Bullosa ◽  
Transmission Electron

Pasini's albopapuloid epidermolysis bullosa is a very rare subtype of generalized dystrophic dominant epidermolyis bullosa. A 30 year-old white female patient presented since her childhood disseminated small blisters and papules. Light microscopy of a blister showed dermal-epidermal cleavage; moreover, focal areas of dermal-epidermal splitting were also observed. Transmission electron microscopy also identified focal areas of cleavage, which were seen below the lamina densa. It is important to recognize this condition as a variant of epidermolysis bullosa, since the most important cutaneous findings are generalized papules and not blisters and erosions as in other forms of epidermolysis bullosa.

scholarly journals Clostridium perfringens produces an adhesive pilus required for the pathogenesis of necrotic enteritis in poultry

2021 ◽  
Author(s):  
D. Lepp ◽  
Y. Zhou ◽  
S. Ojha ◽  
I. Mehdizadeh Gohari ◽  
J. Carere ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Clostridium Perfringens ◽  
Direct Evidence ◽  
Necrotic Enteritis ◽  
Null Mutant ◽  
Transmission Electron ◽  
Mutant Strains ◽  
Important Disease

Clostridium perfringens Type G strains cause necrotic enteritis (NE) in poultry, an economically important disease that is a major target of in-feed antibiotics. NE is a multifactorial disease, involving not only the critically-important NetB toxin, but also additional virulence and virulence-associated factors. We previously identified a C. perfringens chromosomal locus (VR-10B) associated with disease-causing strains that is predicted to encode a sortase-dependant pilus. In the current study, we sought to provide direct evidence for the production of a pilus by C. perfringens and establish its role in NE pathogenesis. Pilus structures in virulent C. perfringens strain CP1 were visualized by transmission electron microscopy (TEM) of immuno-gold labelled cells. Filamentous structures were observed extending from the cell surface in wild-type CP1, but not from isogenic pilin-null mutant strains. In addition, immuno-blotting of cell surface proteins demonstrated that CP1, but not the null mutant strains, produced a high molecular weight ladder-like pattern characteristic of a pilus polymer. Binding to collagen types I, II and IV was significantly reduced (Tukey’s; p<0.01) in all three pilin mutants compared to CP1, and could be specifically blocked by CnaA and FimA antisera, indicating that these pilins participate in adherence. Furthermore, both fimA and fimB null mutants were both severely attenuated in their ability to cause disease in an in vivo chicken NE challenge model. Together, these results provide the first direct evidence for the production of a sortase-dependant pilus by C. perfringens, and confirm its critical role in NE pathogenesis and collagen-binding. Importance In necrotic enteritis (NE), an intestinal disease of chickens, Clostridium perfringens cells adhere tightly to damaged intestinal tissue, but the factors involved are not known. We previously discovered a cluster of C. perfringens genes predicted to encode a pilus, a hair-like bacterial surface structure commonly involved in adherence. In the current study, we have directly imaged this pilus using transmission electron microscopy (TEM). We also show that inactivation of the pilus genes stops pilus production, significantly reducing the bacterium's ability to bind collagen and cause disease. Importantly, this is the first direct evidence for the production of a sortase-dependant pilus by C. perfringens, revealing a promising new target for developing therapeutics to combat this economically important disease.

Localization of microfilament bundles in the upper layer of the primitive-streakstage chick blastoderm

Development ◽  
1982 ◽  
Vol 67 (1) ◽  
pp. 59-70
Author(s):  
L. Vakaet ◽  
Ch. Vanroelen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Close Association ◽  
Primitive Streak ◽  
Neural Plate ◽  
Junctional Complex ◽  
Apical Surface ◽  
Chick Blastoderm ◽  
Transmission Electron ◽  
Microfilament Bundles

Transmission electron microscopy of medium-streak-stage chick blastoderms revealed the presence of 4–6 nm microfilament bundles just under the apical surface of upper layer cells, in close association with the junctional complex. The presence of these microfilament bundles was not restricted to the centre of the primitive streak, but they were also observed in the presumptive neural plate and lateral to the anterior half of the primitive streak. The microfilament bundles are thought to be involved in every morphogenetic movement in the upper layer and not to be restricted to groove formation.

scholarly journals A pre-embedding immunolabeling technique for basal lamina and extracellular matrix molecules.

1988 ◽  
Vol 36 (4) ◽  
pp. 453-458 ◽  
Author(s):  
M M Martins-Green ◽  
K T Tokuyasu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Extracellular Matrix ◽  
Optical Microscopy ◽  
Basal Lamina ◽  
Serial Sections ◽  
Stages Of Development ◽  
Additional Advantage ◽  
Transmission Electron ◽  
Extracellular Matrix Molecules

We have developed a pre-embedding immunolabeling technique to identify basal lamina and extracellular matrix molecules in embryos at various stages of development. The technique works for both fluorescence optical microscopy (1-2.5-micron sections) and for transmission electron microscopy, and enables straigthforward correlation between the two. An additional advantage is the easy preparation of well-oriented serial sections, facilitating detailed studies of development.

scholarly journals Embedding cell monolayers to investigate nanoparticle-plasmalemma interactions at transmission electron microscopy

2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Manuela Costanzo ◽  
Manuela Malatesta
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Inexpensive Method ◽  
Biological Barrier ◽  
Cell Monolayers ◽  
Ultrastructural Evidence ◽  
Transmission Electron ◽  
Uptake Process ◽  
Intracellular Fate

Transmission electron microscopy is the technique of choice to visualize the spatial relationships between nanoconstructs and cells and especially to monitor the uptake process of nanomaterials. It is therefore crucial that the cell surface be preserved in its integrity, to obtain reliable ultrastructural evidence: the plasmalemma represents the biological barrier the nanomaterials have to cross, and the mode of membrane-nanoconstruct interaction is responsible for the intracellular fate of the nanomaterials. In this paper, we describe a simple and inexpensive method to process cell monolayers for ultrastructural morphology and immunocytochemistry, ensuring consistent preservation of the cell surface and of the occurring interactions with nanoparticles of different chemical composition.

Surface membrane regeneration in deciliated Tetrahymena

1983 ◽  
Vol 62 (1) ◽  
pp. 407-417
Author(s):  
N.E. Williams
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Surface Membrane ◽  
Membrane System ◽  
Ciliated Protozoa ◽  
Membrane Flow ◽  
Transmission Electron ◽  
Surface Marking

The induced synthesis of identified surface membrane proteins has been demonstrated in deciliated Tetrahymena. Cells in the process of regenerating cilia were also studied using transmission electron microscopy in order to obtain information on the deployment of new membrane at the cell surface. The results obtained suggest a pattern of membrane flow that includes the ‘pellicular alveoli’, a subsurface membrane system characteristically present in ciliated protozoa. The results of 125I surface-marking experiments were consistent with the notion that new membrane is added initially in non-ciliated regions, then subsequently flows laterally to cover regenerating cilia.

scholarly journals Immunomagnetic Purification of Colletotrichum lindemuthianum Appressoria

2000 ◽  
Vol 66 (8) ◽  
pp. 3464-3467 ◽  
Author(s):  
Katie A. Hutchison ◽  
Sarah E. Perfect ◽  
Richard J. O'Connell ◽  
Jonathan R. Green
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibody ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Cell Walls ◽  
Biochemical Analysis ◽  
Immunomagnetic Separation ◽  
Colletotrichum Lindemuthianum ◽  
Transmission Electron ◽  
Bean Anthracnose

ABSTRACT We developed a method to purify appressoria of the bean anthracnose fungus Colletotrichum lindemuthianum for biochemical analysis of the cell surface and to compare appressoria with other fungal structures. We used immunomagnetic separation after incubation of infected bean leaf homogenates with a monoclonal antibody that binds strongly to the appressoria. Preparations with a purity of >90% could be obtained. Examination of the purified appressoria by transmission electron microscopy showed that most had lost their cytoplasm. However, the plasma membrane was retained, suggesting that there is some form of attachment of this membrane to the cell wall. The purified appressoria can be used for studies of their cell surface, and we have shown that there are clear differences in the glycoprotein constituents of cell walls of appressoria compared with mycelium.

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