Sur la différenciation des trachéides dans les haustoriums d'Osyris alba parasitant Hedera helix

1987 ◽  
Vol 65 (8) ◽  
pp. 1746-1755 ◽  
Author(s):  
H. Benharrat ◽  
S. Renaudin ◽  
L. Rey ◽  
P. Thalouarn
Keyword(s):  
Golgi Apparatus ◽  
Secondary Wall ◽  
Multivesicular Bodies ◽  
Tracheary Elements ◽  
Hedera Helix ◽  
Second Stage ◽  
Host Root ◽  
Cytoplasmic Content ◽  
Cambial Cells ◽  
Surrounding Membrane

The central part of the haustorium of Osyris alba L. contains a cambium which is continuous from the mother root to the vicinity of the "absorbing cells." It centripetally differentiates tracheary elements which make up a vascular core, the xylem bridge, connecting the vessels of the parasite root to those of the host root. In the differentiating cambial cells, a first stage of activity of the Golgi apparatus, which is related to the development of the secondary wall thickenings, is evident. This stage is marked by the presence of numerous vesicles containing an electron dense material and of multivesicular bodies lying near the plasmalemma. The cells also contain numerous spherical granules which, while being mainly proteinaceous, also contain some potassium, calcium, and sulfur. The composition of these granules, the fact that their surrounding membrane is studded with numerous ribosomes and the fact that they often form short chains in a common membranous profile lead us to conclude that they are elaborated in the endoplasmic reticulum. Later in the course of differentiation of those cells, a second stage of activity of the Golgi apparatus can be observed, with the numerous vesicles showing a light content this time. This phase precedes a lysis process during which the cells lose all their cytoplasmic content. Only the granules remain in the differentiated tracheids. [Journal translation]

Torus Structure and Development in the Woods of Ulmus Alata Michx., Celtis Laevigata Willd., and Celtis Occidentalis L.

IAWA Journal ◽  
1990 ◽  
Vol 11 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Roland R. Dute ◽  
Ann E. Rushing
Keyword(s):  
Secondary Wall ◽  
Small Diameter ◽  
Three Dimensions ◽  
Central Layer ◽  
Tracheary Elements ◽  
Pit Membrane ◽  
Celtis Occidentalis ◽  
Celtis Laevigata ◽  
Ulmus Alata ◽  
Grooved Wheel

Pit membranes between tracheary elements of Ulmus alata, Celtis laevigata, and Celtis occidentalis often contained tori. The degree of development of tori varied and was greatest in those membranes connecting elements of small diameter. Complete tori consisted of two wall thickenings adjoined by a central layer. In three dimensions the shape of the torus often approximated a grooved wheel. Initiation of thickening in the pit membrane occurred first on the side of the older cell and was well underway prior to the beginning of secondary wall synthesis. Torus formation resulted from the thickening of the primary walls of the pit membrane. Development of the torus was associated with membranous vesicles and cisternae but not with microtubule complexes as was reported in Osmanthus. The pit membranes in this study are capable of aspiration, and the tori may prevent rupture of the pit membrane during this process.

scholarly journals Langerhans' Cells in Equine Cutaneous Papillomas and Normal Skin

1992 ◽  
Vol 29 (2) ◽  
pp. 152-160 ◽  
Author(s):  
M. Hamada ◽  
M. Takechi ◽  
C. Itakura
Keyword(s):  
Major Histocompatibility Complex ◽  
T Lymphocytes ◽  
Golgi Apparatus ◽  
Langerhans Cells ◽  
Normal Skin ◽  
Multivesicular Bodies ◽  
Major Histocompatibility Complex Antigen ◽  
Histocompatibility Complex ◽  
Thoroughbred Horses ◽  
Normal Epidermis

Langerhans' cells (LC) were investigated immunohistochemically and electron microscopically in normal equine epidermis and 133 equine cutaneous papillomas experimentally induced in five 2-year-old Thoroughbred horses. Class II major histocompatibility complex antigen-positive dendritic LC were found in the normal epidermis and ultrastructurally had the characteristic Birbeck's granules. In the developing phase of the papillomas, LC were significantly decreased in number and size, indicative of a hypofunctional state. In the regressing phase of the papillomas, LC were markedly increased in number, especially at the epidermis-dermis junction. LC with long dendrites were rich in cytoplasm with well-developed cytoplasmic organelles, including Golgi apparatus, lysosomes, Birbeck's granules, and multivesicular bodies. These LC were hyperfunctional. An infiltration of many T lymphocytes was also observed at the epidermis-dermis junction.

scholarly journals Stress-Induced Intracellular Trafficking of Corticotropin-Releasing Factor Receptors in Rat Locus Coeruleus Neurons

Endocrinology ◽  
2007 ◽  
Vol 149 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Beverly A. S. Reyes ◽  
Rita J. Valentino ◽  
Elisabeth J. Van Bockstaele
Keyword(s):  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Locus Coeruleus ◽  
Intracellular Trafficking ◽  
Corticotropin Releasing Factor ◽  
Cellular Trafficking ◽  
Multivesicular Bodies ◽  
Swim Stress ◽  
Early Endosomes ◽  
Crf1 Antagonist

Corticotropin-releasing factor (CRF) activates locus coeruleus (LC)-norepinephrine neurons during stress. Previous stress or CRF administration attenuates the magnitude of this response by decreasing postsynaptic sensitivity to CRF. Here we describe the fate of CRF receptors (CRFr) in LC neurons after stress. Rats were exposed to swim stress or handling and perfused 1 or 24 h later. Sections through the LC were processed for immunogold-silver labeling of CRFr. CRFr in LC dendrites was present on the plasma membrane and within the cytoplasm. In control rats, the ratio of cytoplasmic to total dendritic labeling was 0.55 ± 0.01. Swim stress increased this ratio to 0.77 ± 0.01 and 0.80 ± 0.02 at 1 and 24 h after stress, respectively. Internalized CRFr was associated with different organelles at different times after stress. At 1 h after stress, CRFr was often associated with early endosomes in dendrites and perikarya. By 24 h, more CRFr was associated with multivesicular bodies, suggesting that some of the internalized receptor is targeted for degradation. In perikarya, more internalized CRFr was associated with Golgi apparatus 24 vs. 1 h after stress. This is suggestive of changes in CRFr synthesis. Alternatively, this may indicate communication between multivesicular bodies and Golgi apparatus in the process of recycling. Administration of the selective CRF1 antagonist, antalarmin, before swim stress attenuated CRFr internalization. The present demonstration of stress-induced internalization of CRFr in LC neurons provides evidence that CRF is released in the LC during swim stress to activate this system and initiate cellular trafficking of the receptor that determines subsequent sensitivity of LC neurons to CRF.

Analysis of chemosensory responses of second stage juveniles of Globodera rostochiensis using electrophysiological techniques

Nematology ◽  
2000 ◽  
Vol 2 (5) ◽  
pp. 523-533 ◽  
Author(s):  
Richard Rolfe ◽  
John Barrett ◽  
Roland Perry
Keyword(s):  
Citric Acid ◽  
Sugar Beet ◽  
Spike Activity ◽  
Globodera Rostochiensis ◽  
Feeding Response ◽  
Perfusion System ◽  
Potato Root ◽  
Second Stage ◽  
Host Root ◽  
Elektrische Aktivität

Abstract Electrophysiological techniques were developed to obtain recordings of electrical activity from the anterior end of live, second stage juveniles (J2) of Globodera rostochiensis. Sequential exposure of individual J2 to test semiochemicals was also possible using a modified perfusion system. Concentration-dependent responses were obtained from J2 during exposure to 0.1, 1, 10 and 100 mM acetylcholine. The delay before any response was not concentration-dependent. The responses to 10 mM concentrations of several chemicals known to elicit a feeding response in insects were assessed. There was a significant increase in spike activity when J2 were exposed to D-tryptophan but glycine and citric acid elicited no responses. Exposure to D-glutamic acid resulted in a significant increase in spike activity but exposure to the L-isomer gave no response. This was confirmed by sequential exposure of J2 to the L- then to the D-isomer. Exposure to potato root diffusate elicited a response, whereas a non-host root diffusate from sugar beet and female secretory-excretory (S-E) product caused no change in activity. Die Analyse chemosensorischer Reaktionen von Juvenilen des zweiten Stadiums von Globodera rostochiensis mit elektrophysiologischen Techniken - Zur Gewinnung von Informationen über die elektrische Aktivität des Vorderendes von Juvenilen des zweiten Stadiums (J2) von Globodera rostochiensis wurden elektrophysiologische Untersuchungsmethoden entwickelt. Aufeinander folgende Behandlungen einzelner J2 zur Prüfung von Semiochemikalien wurden auch durch ein verändertes Perfusionssystem erreicht. Bei der Behandlung von J2 mit 0.1, 1, 10 und 100 mM Acetylcholin wurden konzentrationsabhängige Reaktionen erzielt. Die Verzögerung vor dem Sichtbarwerden einer Reaktion war dagegen nicht konzentrationsabhängig. Es wurden auch die Reaktionen auf 10 mM Konzentrationen mehrerer Substanzen geprüft, die bei Insekten eine Nahrungsaufnahme auslösen. Bei D-Tryptophan trat eine deutliche Erhöhung der Spitzenaktivität ein, bei Glycin und Zitronensäure erfolgte keine Reaktion. Eine Behandlung mit DGlutaminsäure erhöhte die Spitzenaktivität deutlich, nicht jedoch das L-Isomer. Diese Beobachtung wurde bestätigt, wenn man die J2 erst dem L- und anschließend dem D-Isomer aussetzte. Die Behandlung mit Kartoffelwurzel-Ablaufwasser rief eine Reaktion hervor, nicht aber Wurzelextrakte des Nichtwirtes Zuckerrübe und Produkte des sekretorisch-exkretorischen Systems von Weibchen.

scholarly journals CYTOCHEMICAL STUDIES OF LYSOSOMES, GOLGI APPARATUS AND ENDOPLASMIC RETICULUM IN SECRETION AND PROTEIN UPTAKE BY ADRENAL MEDULLA CELLS OF THE RAT

1968 ◽  
Vol 16 (5) ◽  
pp. 320-336 ◽  
Author(s):  
ERIC HOLTZMAN ◽  
REGINA DOMINITZ
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Adrenal Medulla ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Multivesicular Bodies ◽  
Frozen Sections ◽  
Protein Uptake ◽  
Thiamine Pyrophosphatase

The adrenalin-producing cells of the rat adrenal medulla have been studied by light and electron microscopy. Frozen sections of glutaraldehyde-perfused material were incubated for demonstration of "marker" enzymes for lysosomes (acid phosphatase, aryl sulfatase) and Golgi apparatus (thiamine pyrophosphatase). In addition, the uptake and fate of intravenously administered horseradish peroxidase was followed. Acid phosphatase activity is demonstrable in secretory granules, Golgi saccules, vesicles in the Golgi area and in the agranular tubules and cisternae (GERL) from which secretory granules appear to form at the inner surface of the Golgi apparatus. Endoplasmic reticulum with ribosomes on only one surface is closely apposed to both inner and outer aspects of the Golgi apparatus. Peroxidase is taken up in vesicles, tubules and "cup-like" bodies. The latter apparently transform into multivesicular bodies. A possible source of the acid phosphatase found in multivesicular bodies is the small vesicles from the Golgi apparatus or GERL.

scholarly journals Influence of temperature and soil type on the histopathology of Meloidogyne incognita on snap beans

1969 ◽  
Vol 71 (1) ◽  
pp. 97-105
Author(s):  
Nydia E. Vicente ◽  
Alejandro Ayala ◽  
Nelia Acosta
Keyword(s):  
Meloidogyne Incognita ◽  
Cell Walls ◽  
Giant Cells ◽  
Small Cells ◽  
Vascular Bundles ◽  
Silty Clay ◽  
Second Stage ◽  
Snap Beans ◽  
Cytoplasmic Content ◽  
Multinucleate Giant Cells

Three groups of seedlings of snap bean cultivars Contender and Conquest were planted in Coto clay, Fraternidad silty clay, and San Antón silt loam; inoculated with 10,000 eggs and second stage juveniles of Meloidogyne incognita and placed in growth chambers at 15, 20 and 25° C for 45 days. Multinucleate giant cells with thick cell walls and dense cytoplasm surrounded by proliferation of small cells, breakdown of cell walls, and malformation of vascular bundles were observed. No giant cells were observed in bacterial nodules, even though several of them were invaded by nematodes. Cytoplasmic content of the giant cells decreased as temperature increased. Nematode numbers within roots increased as the temperature increased. There was a tendency for the formation of oval or rectangular giant cells around the vascular bundles and round giant cells in the cortex. Giant cells with the largest number of nuclei were observed at 20° C, and fewer at 25° C. Giant cell was largest at 20 and 25° C, especially in cv Contender. Necrosis or mechanic injury due to migration of juveniles was not observed. The nematodes appeared to develop best in Fraternidad soil.

Torus-Bearing Pit Membranes in Cercocarpus

IAWA Journal ◽  
2010 ◽  
Vol 31 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Roland Dute ◽  
Jaynesh Patel ◽  
Steven Jansen
Keyword(s):  
Secondary Wall ◽  
Membrane Surface ◽  
Parenchyma Cell ◽  
Protective Layer ◽  
Wall Material ◽  
Tracheary Elements ◽  
Bordered Pit ◽  
Parenchyma Cells ◽  
Conducting Cell ◽  
Cell Ontogeny

Intervascular pit membranes of Cercocarpus possess torus thickenings. The thickenings, or pads, consist of lignified, secondary wall material. Torus pad deposition occurs late in cell ontogeny and is not associated with a microtubule plexus. Half-bordered pit pairs between tracheary elements and parenchyma cells often have a torus pad on the membrane surface facing the conducting cell. In contrast, a thick protective layer fills the pit cavity on the side of the parenchyma cell. Ontogeny of the torus thickenings in Cercocarpus represents a third mode of torus development in eudicots when compared to that occurring in Osmanthus/Daphne and Ulmus/Celtis.

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