scholarly journals Collagen Fibril Ultrastructure in Mice Lacking Discoidin Domain Receptor 1

2016 ◽  
Vol 22 (3) ◽  
pp. 599-611 ◽  
Author(s):  
Jeffrey R. Tonniges ◽  
Benjamin Albert ◽  
Edward P. Calomeni ◽  
Shuvro Roy ◽  
Joan Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Collagen Fibril ◽  
Collagen Fibrils ◽  
Collagen Deposition ◽  
Knock Out ◽  
Discoidin Domain Receptor ◽  
Transmission Electron ◽  
Fibril Diameter ◽  
Discoidin Domain Receptor 1

AbstractThe quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson’s trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM.

Growth and development of collagen fibrils in immature tissues from rat and sheep

1981 ◽  
Vol 212 (1186) ◽  
pp. 85-92 ◽  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Collagen Fibril ◽  
Growth And Development ◽  
Collagen Fibrils ◽  
Diameter Distribution ◽  
Rat Tissues ◽  
Transmission Electron ◽  
The Mean ◽  
Fibril Diameter

The collagen fibril diameter distribution of four immature tissues from both rat and sheep have been determined from transverse sections observed in the transmission electron microscope. In many instances before birth, the form of the distribution for the tissues is both unimodal and sharp and the mean diameters of the distributions lie close to a multiple of 80 Å. For some tissues, the collagen fibril diameter distributions may be resolved into a number of components, each of which represents a population of fibrils with a diameter close to a multiple of 80 Å (8 nm). These data confirm and extend previous observations by the authors that small collagen fibrils all have diameters that are multiples of about 80 Å and that the fibril growth occurs by the accretion of 80 Å units. The form of the collagen fibril diameter distribution at birth is broad for the sheep tissues but narrow for the rat tissues, thus confirming that the range of fibril diameters at this stage of life reflects the differing degree of development of precocious and altricious animals.

scholarly journals Cemp1-p3 Peptide Promotes the Transformation of Octacalcium Phosphate into Hydroxyapatite Crystals

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1131
Author(s):  
Maricela Santana ◽  
Gonzalo Montoya ◽  
Raúl Herrera ◽  
Lía Hoz ◽  
Enrique Romo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Octacalcium Phosphate ◽  
Sequence Motifs ◽  
Simple Method ◽  
Transmission Electron ◽  
Precursor Phase ◽  
Mineralized Tissues ◽  
Potent Growth

Dental cementum contains unique molecules that regulate the mineralization process in vitro and in vivo, such as cementum protein 1 (CEMP1). This protein possesses amino acid sequence motifs like the human recombinant CEMP1 with biological activity. This novel cementum protein 1-derived peptide (CEMP1-p3, from the CEMP1’s N-terminal domain: (QPLPKGCAAVKAEVGIPAPH), consists of 20 amino acids. Hydroxyapatite (HA) crystals could be obtained through the combination of the amorphous precursor phase and macromolecules such as proteins and peptides. We used a simple method to synthesize peptide/hydroxyapatite nanocomposites using OCP and CEMP1-p3. The characterization of the crystals through scanning electron microscopy (SEM), powder X-ray diffraction (XRD), high--resolution transmission electron microscopy (HRTEM), and Raman spectroscopy revealed that CEMP1-p3 transformed OCP into hydroxyapatite (HA) under constant ionic strength and in a buffered solution. CEMP1-p3 binds and highly adsorbs to OCP and is a potent growth stimulator of OCP crystals. CEMP1-p3 fosters the transformation of OCP into HA crystals with crystalline planes (300) and (004) that correspond to the cell of hexagonal HA. Octacalcium phosphate crystals treated with CEMP1-p3 grown in simulated physiological buffer acquired hexagonal arrangement corresponding to HA. These findings provide new insights into the potential application of CEMP1-p3 on possible biomimetic approaches to generate materials for the repair and regeneration of mineralized tissues, or restorative materials in the orthopedic field.

scholarly journals Analytical High-resolution Electron Microscopy Reveals Organ-specific Nanoceria Bioprocessing

2017 ◽  
Vol 46 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Uschi M. Graham ◽  
Robert A. Yokel ◽  
Alan K. Dozier ◽  
Lawrence Drummy ◽  
Krishnamurthy Mahalingam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Analytical Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Dark Field ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Organ Specific

This is the first utilization of advanced analytical electron microscopy methods, including high-resolution transmission electron microscopy, high-angle annular dark field scanning transmission electron microscopy, electron energy loss spectroscopy, and energy-dispersive X-ray spectroscopy mapping to characterize the organ-specific bioprocessing of a relatively inert nanomaterial (nanoceria). Liver and spleen samples from rats given a single intravenous infusion of nanoceria were obtained after prolonged (90 days) in vivo exposure. These advanced analytical electron microscopy methods were applied to elucidate the organ-specific cellular and subcellular fate of nanoceria after its uptake. Nanoceria is bioprocessed differently in the spleen than in the liver.

scholarly journals Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

2010 ◽  
Vol 10 ◽  
pp. 879-893 ◽  
Author(s):  
Nathaniel G. N. Milton ◽  
J. Robin Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Islet Amyloid Polypeptide ◽  
Amyloid Β ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide ◽  
Transmission Electron

The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrilsin vitroandin vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KDof 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

scholarly journals Degradation Behavior, Transport Mechanism and Osteogenic Activity of Mg–Zn–RE Alloy Membranes in Critical-Sized Rat Calvarial Defects

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 496
Author(s):  
Mingyu Zhao ◽  
Guanqi Liu ◽  
Ying Li ◽  
Xiaodong Yu ◽  
Shenpo Yuan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Transport Mechanism ◽  
Degradation Process ◽  
Lymph System ◽  
Transmission Electron ◽  
Calvarial Defects ◽  
Rat Calvarial Defect

In this study, a specific Mg–Zn–RE alloy membrane with 6 wt.% zinc and 2.7 wt.% rare earth elements (Y, Gd, La and Ce) was prepared to investigate implant degradation, transport mechanism and guide bone regeneration in vivo. The Mg-membrane microstructure and precipitates were characterized by the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The Mg-membrane degradation process and effect on osteogenesis were investigated in a critical-sized rat calvarial defect model via micro-CT examination and hard tissue slicing after 2-, 5- and 8-week implants. Then, the distribution of elements in organs after 1-, 2- and 4-weeks implantation was examined to explore their transportation routes. Results showed that two types of precipitates had formed in the Mg–membrane after a 10-h heat treatment at 175 °C: γ-phase MgZn precipitation with dissolved La, Ce and Gd, and W-phase Mg3(Y, Gd)2Zn3 precipitation rich in Y and Gd. In the degradation process of the Mg-membrane, the Mg matrix degraded first, and the rare earth-rich precipitation particles were transferred to a more stable phosphate compound. The element release rate was dependent on the precipitate type and composition. Rare earth elements may be transported mainly through the lymph system. The defects were repaired rapidly by the membranes. The Mg-membrane used in the present study showed excellent biocompatibility and enhanced bone formation in the vicinity of the implants.

scholarly journals Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 263 ◽  
Author(s):  
Maria Letizia Manca ◽  
Iris Usach ◽  
José Esteban Peris ◽  
Antonella Ibba ◽  
Germano Orrù ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Yeast Cells ◽  
Unilamellar Vesicles ◽  
Transmission Electron ◽  
Physico Chemical

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

Yolk platelet degradation in preemergence Artemia embryos: response to protons in vivo and in vitro

1987 ◽  
Vol 252 (4) ◽  
pp. R774-R781 ◽  
Author(s):  
P. J. Utterback ◽  
S. C. Hand
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dry Weight ◽  
Platelet Protein ◽  
Transmission Electron ◽  
Structural Differences ◽  
Alkaline Conditions ◽  
Yolk Platelet

Alteration of intracellular pH (pHi) influences yolk platelet degradation during preemergence development in Artemia embryos. Cysts incubated for 10 h under conditions of aerobic development (aqueous medium equilibrated with 60% N2-40% O2, pHi greater than or equal to 7.9) exhibit a significant decrease in numbers of yolk platelets and platelet protein. In contrast, cysts incubated for 10 h under aerobic acidosis (60% CO2-40% O2, pHi = 6.8) show no significant decrease in numbers of yolk platelets or platelet protein. When subjected to alkaline conditions in vitro, yolk platelets release protein exponentially as a function of time. The process is essentially complete in 40 min. The extent of protein and lipid release from platelets increases markedly as pH of the medium is raised in increments from 6.3 to 8.0. Concomitant with these changes are reduction (50%) in platelet dry weight and reduction (21%) in platelet diameter. Transmission electron microscopy does not reveal major structural differences between isolated yolk platelets and those contained in hydrated embryos. The proton effects on platelet composition and size detected in vitro may explain in part the mechanism of platelet degradation observed during aerobic development and its suppression under conditions of acidic pHi.

scholarly journals Aggregative Behavior of Bacteria Isolated from Canine Dental Plaque

2006 ◽  
Vol 72 (8) ◽  
pp. 5211-5217 ◽  
Author(s):  
David R. Elliott ◽  
Michael Wilson ◽  
Catherine M. F. Buckley ◽  
David A. Spratt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dental Plaque ◽  
Oral Bacteria ◽  
Surface Structures ◽  
Aggregative Behavior ◽  
Transmission Electron

ABSTRACT Interbacterial adhesion of bacteria isolated from canine dental plaque was assessed by performing a visual coaggregation assay. Using conditions mimicking those likely to be encountered in vivo, the entire cultivable plaque microbiota from a single dog was assessed, and eight (6.7%) unique coaggregation interactions were detected for 120 crosses. Transmission electron microscopy was used to visualize several of the bacteria in isolation and as coaggregates, which revealed surface structures that may be involved in adhesion and coaggregation. The results of this study indicate that the prevalence of coaggregating pairs of dental plaque bacteria in dogs is similar to the prevalence of coaggregating pairs of dental plaque bacteria reported in humans. In addition, genera found in both hosts generally exhibited similar coaggregation reactions; however, autoaggregation was found to be more common among oral bacteria isolated from dogs.

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