scholarly journals Electron-Microscopic Investigation of the Flora of Sheep Alimentary Tract

1970 ◽  
Vol 23 (4) ◽  
pp. 793 ◽  
Author(s):  
NJ Hoogenraad ◽  
FJR Hird
Keyword(s):  
Electron Microscopy ◽  
Small Intestine ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Alimentary Tract ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Direct Examination ◽  
Electron Microscopic ◽  
Large Numbers

Digesta from different regions of the sheep alimentary tract have been examined using electron microscopy. Direct examination of digesta from the rumen has revealed the presence of a number of phages and of a large variety of bacteria differing considerably in their morphology. An atlas of electron micrographs of these bacteria has been presented. The presence of large numbers of bacterial cell walls ;n the rumen indicates that the breakdown of bacteria commences in this organ. The major sites of digestion of bacteria are in the abomasum and small intestine where there is a substantial removal and modification of bacteria.

Electron microscopic investigation of the structure and morphology of syndiotactic polypropylene

1989 ◽  
Vol 47 ◽  
pp. 358-359
Author(s):  
Andrew J. Lovinger ◽  
Bernard Lotz ◽  
Don D. Davis
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Dark Field ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Dilute Solution ◽  
Electron Microscopic ◽  
Syndiotactic Polypropylene ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron

In contrast to its isotactic isomer, syndiotactic polypropylene has received only little attention. Our main source of understanding of its structure is the X-ray study by Conradini et al., who found the chains to have a (t2g2)2 conformation (corresponding to a 4∗2/1 helix with molecular repeat 0.74 nm), and to be packed in a C-centered unit cell as shown in the left side of Fig. 1. We have recently begun a study of the structure, crystallization, and morphology of syndiotactic polypropylene using electron microscopy and diffraction. Here we concentrate specifically on the electron-diffraction evidence as a function of temperature, in order to obtain an understanding of the evolution and variation of structure in this polymer.Thin films of syndiotactic polypropylene (synthesized by Dr. R. E. Cais as reported previously) were prepared by casting from dilute solution in xylenes at ca. 140°c onto freshly cleaved mica substrates. Following evaporation of the solvent, they were melted and then isothermally crystallized at a variety of temperatures. After shadowing with Pt/C and coating with carbon, they were floated off their substrates for examination by transmission electron microscopy (bright- and dark-field) and selected-area electron diffraction at 100-200 keV.

Studies on the interactions of immunostimulated macrophages andYersinia enterocoliticaO:8

2000 ◽  
Vol 46 (3) ◽  
pp. 218-228 ◽  
Author(s):  
E Ivanova ◽  
I Yanchev ◽  
H Najdenski ◽  
R Toshkova ◽  
P Dimitrova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Yersinia Enterocolitica ◽  
Peritoneal Macrophages ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Serotype O

Immunological and electron microscopy investigations of the phagocytic and killing activities of peritoneal macrophages from rats and mice against Yersinia enterocolitica serotype O:8 cells were performed. The effect of in vivo application of cytoplasmic membranes (CM) from the stable Escherichia coli WF+ L-form on macrophage activity was also studied. It was established that rat macrophages more actively phagocytosed the plasmidless pYV(-) Y. enterocolitica cells, compared to the plasmid-bearing pYV(+) Y. enterocolitica cells. The killing ability against both variants of the Y. enterocolitica strain was significantly enhanced in macrophages from CM-treated rats after 2 h, 4 h, and 24 h incubation. The CM treatment enhanced the phagocytic activity of the macrophages. The in vitro interaction of normal and immunostimulated rat macrophages with both pYV(+) and pYV(-) variants of Y. enterocolitica did not lead to any additional apoptotic and necrotic changes in macrophages compared to control macrophages, which were cultivated without Y. enterocolitica. Electron-microscopic investigation showed that mouse macrophages eliminated Y. enterocolitica pYV(+) cells in vivo after 24 h. No engulfed or digested bacterial cells were observed. Activation of cell surfaces and vacuolization of macrophage cytoplasm, both of CM-treated non-infected and infected mice, were observed. The experimental results showed that Y. enterocolitica pYV(+) cells could be eliminated by peritoneal macrophages.Key words: Yersinia enterocolitica, immunostimulation, electron microscopy, bacterial L-forms, macrophages.

A Comparative Study of Fractographic Replicas

1974 ◽  
Vol 32 ◽  
pp. 566-567
Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon
Keyword(s):  
Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Direct Examination ◽  
Electron Microscopic ◽  
Reliable Technique ◽  
Service Failures ◽  
Transmission Electron ◽  
Mode Of Failure ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.

Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

1988 ◽  
Vol 46 ◽  
pp. 352-353
Author(s):  
G. Ilse ◽  
K. Kovacs ◽  
N. Ryan ◽  
T. Sano ◽  
L. Stefaneanu ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Aging Male ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Sprague Dawley Rats ◽  
Old Rats ◽  
Ad Libitum ◽  
Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland

1968 ◽  
Vol 26 ◽  
pp. 232-233
Author(s):  
P.W. Coates ◽  
E.A. Ashby ◽  
L. Krulich ◽  
A. Dhariwal ◽  
S. McCann
Keyword(s):  
Anterior Pituitary ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Thin Sections ◽  
Dense Membrane ◽  
Membrane Bound ◽  
Releasing Factors

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.

Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

1975 ◽  
Vol 33 ◽  
pp. 378-379
Author(s):  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Pituitary Adenomas ◽  
Secretory Activity ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Cytoplasmic Staining ◽  
Human Pituitary Gland ◽  
Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

Temporal and spatial interrelationships of confronting cisternae to nuclear envelope

1992 ◽  
Vol 50 (1) ◽  
pp. 930-931
Author(s):  
John R. Palisano
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Tumor Cells ◽  
Hela Cells ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Serial Sections ◽  
Electron Microscopic ◽  
Fetal Rat ◽  
Temporal And Spatial

Although confronting cistemae (CC) have been observed in a variety of tumor cells and normal fetal rat, mouse, and human epithelial tissues, little is known about their origin or role in mitotic cells. While several investigators have suggested that CC arise from nuclear envelope (NE) folding back on itself during prophase, others have suggested that CC arise when fragments of NE pair with endoplasmic reticulum. An electron microscopic investigation of 0.25 um thick serial sections was undertaken to examine the origin of CC in HeLa cells.

Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism

1989 ◽  
Vol 47 ◽  
pp. 848-849
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
L. Stefaneanu ◽  
N. Losinski
Keyword(s):  
Nucleolar Organizer ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Ectopic Acth Syndrome ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Ectopic Acth ◽  
Crooke’S Hyalinization

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.

scholarly journals A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Buzuayehu Abebe ◽  
Enyew Amare Zereffa ◽  
Aschalew Tadesse ◽  
H. C. Ananda Murthy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Field Emission ◽  
Volume Ratio ◽  
Electronic Configuration ◽  
Microscopic Investigation ◽  
Electron Microscopic ◽  
Active Materials ◽  
Scanning Electron

Abstract Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

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