scholarly journals Rhodopsins build up the birefringent bodies of the dinoflagellate Oxyrrhis marina

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Erhard Rhiel ◽  
Christian Hoischen ◽  
Martin Westermann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Amino Acid Sequences ◽  
Fast Fourier Transformation ◽  
Oxyrrhis Marina ◽  
Transmission Electron ◽  
Food Vacuoles ◽  
Size And Morphology

AbstractThe ultrastructure of the birefringent bodies of the dinoflagellate Oxyrrhis marina was investigated by transmission electron microscopy. Ultrathin sectioning revealed that the bodies consist of highly ordered and densely packed lamellae, which show a regular striation along their longitudinal axis. A lattice distance of 6.1 nm was measured for the densely packed lamellae by FFT (Fast Fourier Transformation) analysis. In addition, a rather faint and oblique running striation was registered. Lamellae sectioned rather oblique or almost close to the surface show a honeycombed structure with a periodicity of 7.2–7.8 nm. Freeze-fracture transmission electron microscopy revealed that the lamellae are composed of highly ordered, crystalline arrays of particles. Here, FFT analysis resulted in lattice distances of 7.0–7.6 nm. Freeze-fracture transmission electron microscopy further revealed that the bodies remained intact after cell rupture followed by ascending flotation of the membrane fractions on discontinuous sucrose gradients. The birefringent bodies most likely are formed by evaginations of membranes, which separate the cytoplasm from the food vacuoles. Distinct, slightly reddish-colored areas, which resembled the birefringent bodies with respect to size and morphology, were registered by bright field light microscopy within Oxyrrhis marina cells. An absorbance maximum at 540 nm was registered for these areas, indicating that they are composed of rhodopsins. This was finally proven by immuno-transmission electron microscopy, as antisera directed against the C-terminal amino acid sequences of the rhodopsins AEA49880 and ADY17806 intensely immunolabeled the birefringent bodies of Oxyrrhis marina.

scholarly journals Applicability of Freeze-Fracture and Cryo-TEM to Complex Liquids

1992 ◽  
Vol 00 (7) ◽  
pp. 9-9
Author(s):  
Janet L. Burns ◽  
Richard J. Spontak
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Freeze Fracture ◽  
Traditional Methods ◽  
Conventional Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Multicomponent Complex ◽  
Complex Liquids

Traditional methods of sample preparation and analysis in conventional transmission electron microscopy (TEM) are not readily applicable to multicomponent complex liquids which may contain a wealth of microstructural information. Two techniques which facilitate the study of structure in such liquids are freeze-fracture (FF) TEM and cryo-TEM.

Preparation of Size and Morphology Controlled Gold Nanoparticles in Micro-Emulsion and in Aqueous

2012 ◽  
Vol 184-185 ◽  
pp. 1138-1141
Author(s):  
Yan Biao Zhang ◽  
Xiao Hui Zhang ◽  
Hong Zong Yin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Light Scattering ◽  
Homogeneous Distribution ◽  
Mass Ratio ◽  
Optimum Ratio ◽  
Transmission Electron ◽  
Micro Emulsion ◽  
Size And Morphology

In this study, we prepared gold nanoparticles in micro-emulsion and found the optimum ratio of micro-emulsion for preparing gold nanoparticles. We reported a new stabilizer for preparing gold nanoparticles in aqueous and found the optimum mass ratio between the stabilizer and chlorauric acid. All gold nanoparticles prepared by these two methods were characterized by transmission electron microscopy, ultraviolet-visible spectrophotometer and synchronous light-scattering spectrophotometer. The results of transmission electron microscopy showed that the diameter range of gold nanoparticles prepared in micro-emulsion was 5~10 nm, and that in aqueous was 10~15 nm. They all had homogeneous distribution and dense structures.

A freeze-fracture study of the cuticle of adult Nippostrongylus brasiliensis (Nematoda)

Parasitology ◽  
1993 ◽  
Vol 107 (5) ◽  
pp. 545-552 ◽  
Author(s):  
D. L. Lee ◽  
K. A. Wright ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Freeze Fracture ◽  
Surface Coat ◽  
Nippostrongylus Brasiliensis ◽  
Freeze Fracturing ◽  
Transmission Electron ◽  
Fracture Study ◽  
20 Nm

SUMMARYThe surface of the cuticle of adult Nippostrongylus brasiliensis has been studied by means of the freeze-fracture technique and by transmission electron microscopy. Some of the surface coat appears to have been shed from the surface of the cuticle of adults fixed in situ in the intestine of its host and from the surface of individuals removed from the intestine and freeze-fractured. Freeze-fracturing the cuticle of individuals removed from the host has shown that this surface coat varies in thickness from 30 to 90 nm. The epicuticle is about 20 nm thick and cleaves readily to expose E- and P-faces. The P-face of the epicuticle possesses a small number of particles, similar to intra-membranous particles, whilst the E-face possesses a few, widely scattered depressions. Despite the presence of these particles the epicuticle is not considered to be a true membrane. Freeze-fracturing the remainder of the cuticle has confirmed its structure as described by conventional transmission electron microscopy. Clusters of particles on the P-face of the outer epidermal (hypodermal) membrane and corresponding depressions on the E-face of the membrane are thought to be associated with points of attachment of the cuticle to the epidermis (hypodermis). No differences in appearance of the cuticle and its surface layers were observed in individuals taken from 7-, 10-, 13- and 15-day infections.

Freeze-fracture Transmission Electron Microscopy (FF/TEM) studies of systems containing self-associated structures

1993 ◽  
Vol 51 ◽  
pp. 50-51
Author(s):  
Janet L. Burns ◽  
Matthew H. Chestnut ◽  
Richard J. Spontak
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Self Organized ◽  
Transmission Electron ◽  
Internal Phase ◽  
Powerful Means ◽  
Nonaqueous Gel

Freeze-fracture transmission electron microscopy (FF/TEM) is a well-established and highly-valued technique, often employed in the study of biological systems which are extremely sensitive to structural alteration (e.g., membranes and tissues). The technique relies on rapid specimen cooling to immobilize detailed microstructure, usually in a hydrated environment, prior to fracture and subsequent surface replication. As Zasadzinski and Bailey point out, though, the principle governing this technique is general and can be applied with equal success to the study of “microstructured” or “complex” fluids, i.e., fluids consisting of self-organized supramolecular structures. In this vein, FF/TEM constitutes a powerful means of characterizing the structural attributes of dispersions, emulsions, gels, and liquid crystalline assemblies at relatively high spatial resolution. Such morphological information can prove valuable in the development of the structure-viscosity relationships needed in processing. Here, we demonstrate the utility of FF/TEM in elucidating the role of self-associated structures in three different systems: a chemical reaction environment, a high-internal-phase emulsion, and a nonaqueous gel.

scholarly journals The Effect of Stirring on the Morphology of Birnessite Nanoparticles

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Marcos A. Cheney ◽  
Pradip K. Bhowmik ◽  
Shingo Moriuchi ◽  
Mario Villalobos ◽  
Shizhi Qian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Structure ◽  
Dendritic Morphology ◽  
X Ray Diffraction ◽  
Mechanical Stirring ◽  
Transmission Electron ◽  
Initial Stage ◽  
Structural Preferences ◽  
Size And Morphology

The effect of mechanical stirring on the morphology of hexagonal layer-structure birnessite nanoparticles produced from decomposition ofKMnO4in dilute aqueousH2SO4is investigated, with characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), andN2adsorption (BET). Mechanical stirring during an initial stage of synthesis is shown to produce black birnessite containing nanofibers, whereas granular particulates of brown birnessite are produced without stirring. This is the first reduction synthesis of black birnessite nanoparticles with dendritic morphology without any use of organic reductant, and suggests that a particular morphology can arise from structural preferences of Mn in acidic conditions rather than particular organic reactants. These results enlighten the possibility of synthesizing nanoparticles with controlled size and morphology.

scholarly journals Gold Nanopeanuts as Prospective Support for Cisplatin in Glioblastoma Nano-Chemo-Radiotherapy

2020 ◽  
Vol 21 (23) ◽  
pp. 9082
Author(s):  
Joanna Depciuch ◽  
Justyna Miszczyk ◽  
Alexey Maximenko ◽  
Piotr M. Zielinski ◽  
Kamila Rawojć ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Active Surface ◽  
Longitudinal Axis ◽  
Scanning Calorimetry ◽  
Transverse Axis ◽  
Transmission Electron ◽  
Cell Mortality ◽  
20 Nm

Herein, we propose newly designed and synthesized gold nanopeanuts (Au NPes) as supports for cisplatin (cPt) immobilization, dedicated to combined glioblastoma nano-chemo-radiotherapy. Au NPes offer a large active surface, which can be used for drugs immobilization. Transmission electron microscopy (TEM) revealed that the size of the synthesized Au NPes along the longitudinal axis is ~60 nm, while along the transverse axis ~20 nm. Raman, thermogravimetric analysis (TGA) and differential scanning calorimetry (DCS) measurements showed, that the created nanosystem is stable up to a temperature of 110 °C. MTT assay revealed, that the highest cell mortality was observed for cell lines subjected to nano-chemo-radiotherapy (20–55%). Hence, Au NPes with immobilized cPt (cPt@AuNPes) are a promising nanosystem to improve the therapeutic efficiency of combined nano-chemo-radiotherapy.

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