Sonochemical effect of flat sweep frequency and pulsed ultrasound (FSFP) treatment on stability of phenolic acids in a model system

Many studies have shown that the Golgi apparatus is involved in a variety of synthetic activities, and probably no Golgi product is more elaborate than the scales produced by various kinds of phytoflagellates. The formation of calcified scales (coccoliths, Fig. 1,2) of the coccolithophorid phytoflagellates provides a particularly interesting model system for the study of biological mineralization, and the sequential formation of Golgi products.The coccoliths of Hymenomonas carterae consist of a scale-like base (Fig. 2 and 4, b) with a highly structured calcified (CaCO3) rim composed of two distinct elements which alternate about the base periphery (Fig. 1 and 3, A, B). Each element is enveloped by a sheath-like organic matrix (Fig. 3; Fig. 4, m).

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Existence of DNA in yeast microbodies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082029 ◽

1978 ◽

Vol 36 (2) ◽

pp. 232-233

Author(s):

Masako Osumi ◽

Misuzu Nagano ◽

Hiroko Kazama

Keyword(s):

Catalase Activity ◽

Buoyant Density ◽

Model System ◽

Contour Length ◽

Native State ◽

Normal Alkane ◽

Remarkable Increase ◽

Dna Molecule ◽

Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

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The coprecipitation of Cr3P and Cr in Cu

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105886 ◽

1988 ◽

Vol 46 ◽

pp. 764-765

Author(s):

M.J. Witcomb ◽

U. Dahmen ◽

K.H. Westmacott

Keyword(s):

Orientation Relationship ◽

Interface Structure ◽

Model System ◽

Relative Orientation ◽

Age Hardening ◽

Precipitation Behavior ◽

Solution Treated ◽

Small Needle ◽

Diffraction Patterns ◽

Interface Structures

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.

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Record Wear Studies by Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101578 ◽

1968 ◽

Vol 26 ◽

pp. 364-365

Author(s):

M.D. Coutts ◽

E.R. Levin ◽

J.G. Woodward

Keyword(s):

Electron Microscopy ◽

Constant Velocity ◽

Peak Velocity ◽

Great Depth ◽

Depth Of Focus ◽

Sweep Frequency ◽

Transmission Electron ◽

Test Record ◽

Lateral Mode ◽

Scanning Electron

While record grooves have been studied by transmission electron microscopy with replica techniques, and by optical microscopy, the former are cumbersome and restricted and the latter limited by lack of depth of focus and resolution at higher magnification. With its great depth of focus and ease in specimen manipulation, the scanning electron microscope is admirably suited for record wear studies.A special RCA sweep frequency test record was used with both lateral and vertical modulation bands. The signal is a repetitive, constant-velocity sweep from 2 to 20 kHz having a duration and repetitive rate of approximately 0.1 sec. and a peak velocity of 5.5 cm/s.A series of different pickups and numbers of plays were used on vinyl records. One centimeter discs were then cut out, mounted and coated with 200 Å of gold to prevent charging during examination. Wear studies were made by taking micrographs of record grooves having 1, 10 and 50 plays with each stylus and comparing with typical “no-play” grooves. Fig. 1 shows unplayed grooves in a vinyl pressing with sweep-frequency modulation in the lateral mode.

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Membrane-associated microtubular areays induced in proximal myelinated processes of dorsal root ganglia by large doses of vitamin B6

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143468 ◽

1986 ◽

Vol 44 ◽

pp. 368-369

Author(s):

V.J. Montpetit ◽

S. Dancea ◽

L. Tryphonas ◽

D.F. Clapin

Keyword(s):

Animal Model ◽

Endoplasmic Reticulum ◽

Dorsal Root Ganglia ◽

Rough Endoplasmic Reticulum ◽

Dorsal Root ◽

Vitamin B6 ◽

Morphological Changes ◽

Model System ◽

Sensory Nerves ◽

Peripheral Sensory

Very large doses of pyridoxine (vitamin B6) are neurotoxic in humans, selectively affecting the peripheral sensory nerves. We have undertaken a study of the morphological and biochemical aspects of pyridoxine neurotoxicity in an animal model system. Early morphological changes in dorsal root ganglia (DRG) associated with pyridoxine megadoses include proliferation of neurofilaments, ribosomes, rough endoplasmic reticulum, and Golgi complexes. We present in this report evidence of the formation of unique aggregates of microtubules and membranes in the proximal processes of DRG which are induced by high levels of pyridoxine.

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