COMPARATIVE EFFECT OF INSULIN ON EXPLANTED ADRENAL MEDULLARY TISSUE AND RAT ADRENAL MEDULLA IN SITU

1975 ◽  
Vol 64 (2) ◽  
pp. 323-NP ◽  
Author(s):  
R. S. PIEZZI ◽  
L. A. POHORECKY ◽  
J. C. CAVICCHIA ◽  
J. P. GALLEANO

SUMMARY The adrenal medulla and explanted medullary cells in the anterior chamber of the eye were examined 3 h after the administration of insulin to rats. No alterations were seen in the explanted cells. In the adrenal medulla, light and electron microscopy indicated depletion of adrenaline cells; noradrenaline cells were not affected. Levels of catecholamines were three times higher in the explanted tissue after insulin treatment; in the medulla in situ they declined by 70%. These results confirm that insulin has no direct releasing effect on chromaffin cells.

1987 ◽  
Vol 65 (6) ◽  
pp. 588-592 ◽  
Author(s):  
Nicole Gallo-Payet ◽  
Pierre Pothier ◽  
Henri Isler

Using light and electron microscopy, we have observed the presence of rays containing medullary tissue extending across the cortex of rat adrenal glands. Within these rays chromaffin cells, as well as collagen and nerve fibers, were present. It is suggested that these endocrine cells may have a paracrine function within the cortex, possibly via their secretory product.


Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.


2016 ◽  
Vol 106 (2) ◽  
pp. 142-154 ◽  
Author(s):  
J. M. Cicero ◽  
T. W. Fisher ◽  
J. K. Brown

The potato psyllid Bactericera cockerelli is implicated as the vector of the causal agent of zebra chip of potato and vein-greening of tomato diseases. Until now, visual identification of bacteria in the genus ‘Candidatus Liberibacter’ has relied on direct imaging by light and electron microscopy without labeling, or with whole-organ fluorescence labeling only. In this study, aldehyde fixative followed by a coagulant fixative, was used to process adult psyllids for transmission electron microscopy (TEM) colloidal gold in situ hybridization experiments. Results indicated that ‘Ca. Liberibacter solanacearum’ (CLso)-specific DNA probes annealed to a bacterium that formed extensive, monocultural biofilms on gut, salivary gland, and oral region tissues, confirming that it is one morphotype of potentially others, that is rod-shaped, approximately 2.5 µm in diameter and of variable length, and has a rough, granular cytosol. In addition, CLso, prepared from shredded midguts, and negatively stained for TEM, possessed pili- and flagella-like surface appendages. Genes implicating coding capacity for both types of surface structures are encoded in the CLso genome sequence. Neither type was seen for CLso associated with biofilms within or on digestive organs, suggesting that their production is stimulated only in certain environments, putatively, in the gut during adhesion leading to multiplication, and in hemolymph to afford systemic invasion.


Author(s):  
D. L. Taylor

The intertidal actinian Anemonia sulcata is known to harbour yellow-brown algal symbionts which are similar in appearance to the zooxanthellae of hermatypic, or reef-building, corals and a number of other invertebrate species. The cytochemistry and structural morphology of the zooxanthella has been studied by light and electron microscopy, to help define it taxonomically and to reveal something about its relations with the actinian. These investigations confirm that it is a dinoflagellate and have revealed several structural adaptations which are formed as a result of the peculiar mode of life adopted by this alga. Of significance is the fine structure of the periplast, which may have a considerable bearing upon the type of relationship which can exist between the host and its symbiont. These findings are discussed in terms of other known instances of algal-invertebrate symbiosis.


Author(s):  
Sheila S. Emmett ◽  
J. C. Thaemert

The acquisition of serial sections of the atrioventricular node for light and electron microscopy is a formidable task. Ordinary techniques are not adequate if the best possible results are to be achieved at the electron microscopic level. The techniques outlined below have proven to be valuable in locating and determining the position of the AV node.Whole hearts of 2-week old mice were fixed, in situ, by perfusion with 1% phosphate-buffered osmium tetroxide. The hearts were removed from the animals, sectioned transversely into 3 slices approximately equal in thickness, dehydrated in graded concentrations of ethanol and embedded in Epon 812. The block faces were trimmed to a trapezoidal shape ranging in size from 0.75 x 1 mm to 4 x 5 mm. Serial sections approximately 2 microns in thickness were cut with glass knives on a Porter-Blum MT-2 Ultramicrotome. While floating on a drop of water on the knife, each section was stretched with 1 drop of a 1:1, xylene in chloroform mixture applied directly to the section. The sections were picked up individually with a brush, transferred to a glass slide and oven dried for several hours prior to staining.


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