Notizen: Changes in the Iron and Phosphorus Content of Stroma Inclusions during Etioplast-Chloroplast Development in Nicotiana

1977 ◽  
Vol 32 (1-2) ◽  
pp. 139-142
Author(s):  
B. Jülich ◽  
G. Gliem ◽  
A. G. S Jánossy
Keyword(s):  
Conformational Changes ◽  
Phosphorus Content ◽  
Chloroplast Development ◽  
Prolamellar Body ◽  
High Electron ◽  
Formation Processes ◽  
Thin Sections ◽  
X Ray ◽  
Transmission Electron ◽  
Phosphorus Containing

Conformational changes of the thylakoid arrangement during light-dependent etioplast-chloroplast development in cotyledons of Nicotiana clevelandii X N. glutinosa are correlated with a decrease of the iron and phosphorus content in electron-dense stroma inclusions. Parallel to the transformation of the prolamellar body and the stacking process of the thylakoids, both the iron and phosphorus content of the inclusions were found to be reduced. Their elemental composition was analysed by means of the energy-dispersive X-ray microanalysis. Due to their high electron-density these stroma inclusions can be observed by conventional transmission electron microscopy in unstained thin-sections from exclusively glutaraldehyde-fixed material. They seem to be involved in membrane formation processes concomitant with the dispersal of the prolamellar bodies. Thus, the iron and phosphorus containing inclusions were found either closely surrounded by membranes or in the intralamellar space of plastids from plantlets illuminated for 1 - 8 hours. In chloroplasts (illumination period 12 -24 hours) no connections between these inclusions and the thylakoids were noticed.

Ultrahistochemical Analysis of the Chick Embryo Cornea Using A Non-Dispersive X-Ray Detector

1972 ◽  
Vol 30 ◽  
pp. 404-405
Author(s):  
T. Ohkura ◽  
M. Takashio ◽  
T. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Chick Embryo ◽  
Alcian Blue ◽  
Uranyl Acetate ◽  
Lead Citrate ◽  
Thin Sections ◽  
X Ray ◽  
Transmission Electron ◽  
Glutaraldehyde Solution ◽  
Tissue Specimens

The experiments which we report here were performed to show qualitatively the presence or abscence of Cu in the mesostroma of the chick embryo cornea stained with alcian blue 8GS. Strips of the cornea were fixed in a buffered glutaraldehyde solution (2.5%, pH 7.4) and coloured with alcian blue 8GS at pH 2.5. Tissue specimens were postosmicated, dehydrated and embedded in Epon. Tissue blocks for the conventional transmission electron microscopy were prepared without alcian blue treatment, and the thin sections were stained with uranyl acetate and/or lead citrate. Fig. la shows the mesostroma of 3rd day chick embryo cornea; filaments run in various directions, and reveal no visible periodicity. Interfibrillar substances can not be demonstrated by the conventional method of the electron staining. The alcian blue treatment reveals the interfibrillar substances, which stand out in contrast as shown in Fig. lb.

Novel flame retardant epoxy/clay nanocomposites prepared with a pre-ground phosphorus-containing organoclay

2008 ◽  
Vol 23 (6) ◽  
pp. 1618-1630 ◽  
Author(s):  
Y.W. Chen-Yang ◽  
W.S. Wang ◽  
J.C. Tang ◽  
Y.W. Wu ◽  
H.S. Chen
Keyword(s):  
Electron Microscopy ◽  
Surface Hardness ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
Transmission Electron ◽  
Phosphorus Containing ◽  
Large Increment ◽  
Silicate Layers

A series of novel epoxy/clay nanocomposites (EPOCg-x) were prepared with a selected epoxy resin and x wt% of a mechanically ground phosphorus-containing organoclay (POCg). The results of x-ray diffraction (XRD), Fourier transform infrared, and field emission scanning electron microscopy measurements showed that POCg was size-reduced, and its silicate layers were disordered by the grinding process. The results of XRD and transmission electron microscopy of the nanocomposites suggested that the POCg particles were well-dispersed in the epoxy matrix with a combination of intercalation and destruction platelet structures. The as-prepared nanocomposites remained thermally stable above 376 °C. Furthermore, the storage modulus in the glass state, surface hardness, char residue, and limiting oxygen index (LOI) of the as-prepared nanocomposite were all significantly increased with increasing the POCg content. The large increment of LOI, 10 units higher than that of neat epoxy, indicated that an extraordinary enhancement on flame retardancy was obtained from EPOCg-5.

The detection of P and Ca by X-ray microanalysis in the cyto-chemical reaction product of alkaline phosphatase in the epithelial surface of the rat duodenum

1978 ◽  
Vol 36 (2) ◽  
pp. 128-129
Author(s):  
Takashi Makita
Keyword(s):  
Alkaline Phosphatase ◽  
Lateral Wall ◽  
Transmission Electron Micrograph ◽  
Epithelial Surface ◽  
Fixed Tissue ◽  
Thin Sections ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Rat Duodenum

Alkaline phosphatase activity (ALP-ase) can be localized both over the brush border and on the lateral wall of the duodenal columnar epithelium. (Figs.1,2). Dense precipitate can also be observed on or in the mucus ‘bodies’present on the luminal surface. (Figs.3,4). In order to find out whether it is real phosphatase reaction product(lead phosphate) or not, unstained semi-thin sections (3-500 nm) of glutaraldehyde- fixed tissue, were subjected to X-ray microanalysis, after being incubated in an appropriate substrate medium (Mayahara's lead citrate method), post-fixed in buffered OsO4, and embedded in Spurr resin. A scanning transmission electron micrograph(STEM) was first taken at 25-50 kv(JEOL 50A SEM or 100 C TEM),after which the section was analysed by either a wavelength dispersive detector attached to the SEM or an energy dispersive type enfaced to the TEM at 40-60 kv.

Composition and ultrastructure of the sporangiospore wall of Rhizopus stolonifer

1988 ◽  
Vol 34 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Maria R. Diaz-Torres ◽  
Felix Claverie-Martin ◽  
Michael J. Geoghegan
Keyword(s):  
Electron Microscopy ◽  
Protein S ◽  
Spore Wall ◽  
High Electron ◽  
Uronic Acids ◽  
Rhizopus Stolonifer ◽  
Thin Sections ◽  
Transmission Electron ◽  
Innermost Layer ◽  
Amorphous Surface

The chemical composition and ultrastructure of the cell wall of Rhizopus stolonifer sporangiospores were determined. Spores were examined by transmission electron microscopy using both thin sections and surface replicas, and by scanning electron microscopy. The spore wall was found to be composed of three layers: (i) a ridged electron-opaque outer layer (10–240 nm thick) occasionally covered by a very thin extra layer; (ii) an electron-transparent layer containing electron-dense areas (160–245 nm thick); and (iii) an innermost layer of relatively high electron density overlaying the plasma membrane (15–40 nm thick). The spore wall had a rough amorphous surface without rodlet fascicles. Chemical analysis showed that the major components were protein, glucan, chitosan, and melanin, followed by smaller amounts of uronic acids, lipids, chitin, and mannose. The protein(s) contained high levels of aspartic acid and glutamic acid, followed by glycine, alanine, lysine, histidine, serine, and by smaller amounts of other amino acids. Melanin was intimately associated with protein and glucosamine.

Scanning transmission electron microscopy and X-ray microanalysis of unstained biological thin sections

1978 ◽  
Vol 36 (2) ◽  
pp. 110-111
Author(s):  
R. Freeman ◽  
G.W. Griffiths ◽  
A. V. Jones ◽  
K.R. Leonard
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Collection Efficiency ◽  
Individual Element ◽  
Fresh Tissue ◽  
Thin Sections ◽  
X Ray ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope (STEM) has two distinct advantages over the conventional transmission electron microscope (CTEM) for the investigation of low contrast specimens such as unstained thin sections. These are the much higher collection efficiency for scattered electrons and the possibility of electronic enhancement of the image forming signal. The addition of an X-ray analysis system to STEM may also enable the identification of some of the elements contributing to the overall image contrast and to detect individual element concentrations in features of high contrast occurring in the specimens.Fresh tissue was fixed in 1-2.5% glutaraldehyde in PIPES buffer, quickly dehydrated in ethanol and embedded in epon. Thin (silver/grey) sections were collected on carbon coated copper or nylon grids and viewed in the STEM without further treatment. The microscope used was a Vacuum Generators HB5 STEM with field emission source operating at lOOkV with simultaneous bright field (BF) and dark field (DF) detection systems.

Effect of Phosphorus on Anodic Dissolution and Passivation of Nickel in Near-Neutral Solutions

CORROSION ◽  
1985 ◽  
Vol 41 (12) ◽  
pp. 700-706 ◽  
Author(s):  
J. Flis ◽  
D. J. Duquette
Keyword(s):  
Anodic Dissolution ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Detrimental Effect ◽  
Phosphorus Content ◽  
Electroless Nickel ◽  
X Ray ◽  
Phosphorus Containing ◽  
Nickel Deposits ◽  
Passivating Films

Abstract Anodic dissolution of nickel, electroless nickel deposits with 2.9 and 12.3 wt% P, and amorphous Ni81P19 alloy was examined in sodium hydroxide, sulfate, borate, and chloride solutions at 25 C. Phosphorus enhanced the anodic dissolution of nickel; however, the dissolution decreased as the phosphorus content rose from 2.9 to 12.3%. Auger electron spectroscopy (AES) analysis indicated that oxide-passivating films on the NiP materials were thinner than those on nickel, while scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) examinations revealed the precipitation of phosphorus-containing corrosion products at the surface of the NiP materials. It is suggested that the detrimental effect of phosphorus on corrosion resistance of nickel is associated with lower protectiveness of the oxide film, whereas the inhibitive effect at the higher phosphorus contents can be associated with the formation of phosphates.

scholarly journals Straightforward synthesis of gold nanoparticles by adding water to an engineered small dendrimer

2020 ◽  
Vol 11 ◽  
pp. 1110-1118 ◽  
Author(s):  
Sébastien Gottis ◽  
Régis Laurent ◽  
Vincent Collière ◽  
Anne-Marie Caminade
Keyword(s):  
Gold Nanoparticles ◽  
Self Assembly ◽  
Colloidal Suspensions ◽  
Water Soluble ◽  
X Ray ◽  
Small Water ◽  
Transmission Electron ◽  
Phosphorus Containing ◽  
Edx Analyses ◽  
Powdered Form

A small water-soluble phosphorus-containing dendrimer was engineered for the complexation of gold(I) and for its reduction under mild conditions. Gold nanoparticles were obtained as colloidal suspensions simply and only when the powdered form of this dendrimer was dissolved in water, as shown by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analyses. The dendrimers acted simultaneously as mild reducers and as nanoreactors, favoring the self-assembly of gold atoms and promoting the growth and stabilization of isolated gold nanoparticles. Thus, an unprecedented method for the synthesis of colloidal suspensions of water-soluble gold nanoparticles was proposed in this work.

Transmitted Electron Detector and Grid Holder for a JEOL-U3 SEM

1981 ◽  
Vol 39 ◽  
pp. 384-385
Author(s):  
R. A. Smucker ◽  
M. E. Taylor
Keyword(s):  
Single Cells ◽  
Biological Tissues ◽  
Simple Task ◽  
Thin Sections ◽  
Electron Detector ◽  
X Ray ◽  
Small Areas ◽  
Many Instruments ◽  
Transmission Electron ◽  
Aluminum Base

Energy dispersive x-ray microanalysis has become widely used as a supportive technique in studies of biological tissues. Installation and use of the x-ray detector in many instruments such as the JEOL-U3 S.E.M. is a relatively simple task. Microanalysis of bulk specimens is likewise relatively easy to accomplish in the JEOL-U3 S.E.M. However, in order to perform microanalysis on single cells or small areas within a tissue it is desirable to examine thin sections of embedded or cryo-sectioned cells and tissues. Until the present, there hasn't been a transmission electron detector available for the JEOL-U3 except for an expensive unit available from JEOL.A prototype transmission electron detector was obtained for less than $1,000.00. The detector (Fig. 1) was constructed of a quartz light pipe and epoxied to an aluminum base which was mounted, in place of the normal secondary electron detector. A detector was made by forming an optical grade quartz rod to the appropriate geometry. The detection end and the PMT side were ground and polished as needed.

Electron probe x-ray microanalysis of subcellular ion transport in situ

1992 ◽  
Vol 50 (1) ◽  
pp. 16-17
Author(s):  
Avril V. Somlyo ◽  
Andrew P. Somlyo
Keyword(s):  
Electron Probe ◽  
High Electron ◽  
X Rays ◽  
Electron Dose ◽  
Single Spectrum ◽  
Thin Sections ◽  
Fast Electrons ◽  
X Ray

Electron probe x ray microanalysis [EPMA] provides quantitative information within a single spectrum about elements of biological interest with atomic number of 11 or greater. Therefore, the transport of ions and their accompanying co and counter ions across organelle membranes can be studied in situ by sampling within and adjacent to the intracellular organelle of interest under resting and stimulated conditions.EPMA is based on the fact that the ionization of atoms by fast electrons generates x rays having energies characteristic of the excited atoms. The interaction of incident fast electrons with atomic nuclei generates a background of continuum x rays. Elemental quantitation of ultra thin sections with EPMA is generally based on the linear relationship between elemental concentrations and the ratio of the number of characteristic/continuum. The use of this principle, together with the appropriate standards for calibration, has been the most successful approach for quantitative biological EPMA. The spatial resolution of EPMA at present is better than 10 nm and the practical limit of sensitivity for detecting calcium, (albeit with high electron dose), is approximately 0.3 mmol/kg dry wt. Two modes of data collection are utilized: fixed probe analysis of a region of interest or a scanning probe mode, where an x ray spectrum is collected at each picture point, to obtain quantitative elemental x ray maps. To preserve the morphology and the in vivo distribution of diffusible elements, we prepare specimens by rapid freezing in sub cooled Freon or, more recently with a Lifecell CF100 metal are mirror device; thin sections cut at -130 °C to -160 °C on a Reichert cryoultramicrotome. Msec time resolution of physiological are events can be achieved by freeze trapping.

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