Microscopie de la mycoflore des aiguilles de sapin (Abies alba). II. Lophodermium piceae

1986 ◽  
Vol 64 (1) ◽  
pp. 102-107 ◽  
Author(s):  
François Gourbière ◽  
Régis Pépin ◽  
Dominique Bernillon

Colonization of Abies alba Mill, needles by Lophodermium piceae (Fckl.) Höhn. (Ascomycetes, Hypodermataceae) was studied by light and electron microscopy. Internal mycelium is at first extracellular and invades all the tissues of the needle; thereafter hyphae may penetrate all cells. Cytoplasm and walls of living cells (parenchyma, phloem, cellulosic transfusion tissues) are then lysed. Hyphae also invade thick-walled and lignified cells (epidermis, hypodermis, xylem, tracheids, and fibers of transfusion tissues) without major degradation of the cell wall. Ascomatal development is intraepidermic. Colonization of the needles is limited by black areas (the diaphragms), the structure of which is described. Lophodermium piceae is a primary saprophyte. Needles are colonized during senescence but ascomata appear only on fallen needles. There are about 230 ascomata per gram of needles. The ecology of this fungus is compared with that of Thysanophora penicillioides (Roum.) Kendrick on Abies needles and with that of Lophodermium pinastri (Schrad.) Chev. on Pinus needles.

1975 ◽  
Vol 53 (5) ◽  
pp. 483-494 ◽  
Author(s):  
John P. Kalley ◽  
Thana Bisalputra

The formation of the cell wall in the marine dinoflagellate Peridinium trochoideum was studied using light and electron microscopy. In mature, interphase cells, densely staining inclusions termed ‘prothecal bodies’ were found distributed throughout the cytoplasm. Before ecdysis each amorphous prothecal body developed into many vesicles, each of which contained fibrous material in an electron-transparent matrix. The vast number of vesicles so formed may have increased the cell's osmotic pressure enough to initiate ecdysis. At ecdysis the thecal plates and overlying membranes were lost and a new wall was formed by deposition of intact prothecal vesicles at the protoplast surface. The newly formed wall was continuous over the protoplast and no plates existed as such


2004 ◽  
Vol 165 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Karen R. Dell ◽  
Ronald D. Vale

The 2003 International Prize for Biology was awarded to Shinya Inoue for his pioneering work in visualizing dynamic processes within living cells using the light microscope. He and his scientific descendants are now pushing light microscopy even further by developing new techniques such as imaging single molecules, visualizing processes in living animals, and correlating results from light and electron microscopy.


1994 ◽  
Vol 40 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Srabani Banerjee ◽  
Judy Little ◽  
Maria Chan ◽  
Brian T. Luck ◽  
Colette Breuil ◽  
...  

A sensitive immunological tool has been developed to detect the sapstaining fungus Ophiostoma piceae 3871, which plagues the wood industry. Monoclonal antibodies (1F3(1), 4G3(14), 4G2(4), and 2B6(24)) produced against cell wall protein extracts of this fungus were specific. Specificity was estimated by enzyme linked immunosorbent assay, western blotting, and light and electron microscopy using the immunogold technique. Electron microscopy revealed gold particles localized on the outer surface of the cell wall. When screened against 24 biological control fungi the antibodies showed pratically no cross-reactivity (< 4%). When tested against 19 other staining fungi, the antibodies recognized three strains of Ophiostoma piceae, 1F3(1) recognized Phialophora botulispora, and the antibodies showed less than 5% reactivity with the other fungi. Chemical and enzymatic modification of the antigen revealed that the epitopes recognized by the monoclonal antibodies were glycospecific. Although the antibodies were produced against the cell wall protein extracts of the fungus grown in liquid culture, they also recognized the fungus growing in wood and therefore can be employed to investigate wood colonization by this fungus.Key words: Ophiostoma piceae, monoclonal antibodies, glycoprotein.


2021 ◽  
Author(s):  
Clément Chambaud ◽  
Sarah Jane Cookson ◽  
Nathalie Ollat ◽  
Emmanuelle M. F. Bayer ◽  
Lysiane Brocard

Despite recent progress in our understanding of the graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy approach (CLEM) to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing YFP or mRFP in the endoplasmic reticulum allowed the efficient targeting of the grafting interface for under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that 4 classes of PD were formed at the interface and that PD introgression into the call wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these failed PD gives us insights into the process of secondary PD biogenesis. We showed that the thinning of the cell wall and the endoplasmic reticulum-plasma membrane tethering seem to be required for the establishment of symplastic connections between the scion and the rootstock. The resolution reached in this work shows that our CLEM method offer a new scale to the study for biological processes requiring the combination of light and electron microscopy.


1978 ◽  
Vol 26 (10) ◽  
pp. 782-791 ◽  
Author(s):  
N L Pearlmutter ◽  
C A Lembi

Chitin was visualized in cell walls after hydrolysis with potassium hydroxide and subsequent postfixation of the deacetylated polysaccharide (chitosan) in OsO4. Areas of chitin deposition appeared dark borwn by light microscopy and electron dense in the electron microscope. With this method, the presence of chitin was demonstrated in the cell walls of the green alga Pithophora oedogonia (Montagne) Wittrock and two fungi, Ceratocystis ulmi Buism. (C. Moreau) and Blastocladiella emersonii Cantino and Hyatt. Most of the chitin in P. oedogonia ws found in the crosswall disk and small amounts occurred in the outer longitudinal walls. The septal disk of C. ulmi also contained chitin, but significant amounts were present in the inner and outer regions of longitudinal walls as well. Chitin was present throughout the walls of B. emersonii. Small amounts of chitin were not easily demonstrated by this technique, but removal of chitosan by exposure to dilute acetic acid before osmium fixation disrupted cell wall integrity, suggesting that small amounts of the structural polysaccharide had been removed.


1980 ◽  
Vol 58 (12) ◽  
pp. 1394-1404 ◽  
Author(s):  
F.H. J. Rijkenberg ◽  
G. T. N. De Leeuw ◽  
K. Verhoeff

A light microscopy study of the host–parasite relationship of Botrytis cinerea on immature tomato fruits was combined with an electron microscopy examination. Both techniques indicate that the cuticle is dissolved enzymatically rather than ruptured mechanically. Inter- and intracellular hyphae have no apparent effect on the cuticle, but do break down wall material. If the penetration tube development is arrested after emerging from the cuticle into the wall, wall discolouration and wall thickening become evident and a considerable increase in host cell organelles below the penetration site is observed. A papilla is also apposited. At successful penetration, when the hypha emerges from the cell wall into the host cell, little cell wall discolouration at the infection site is evident, but the cytoplasm becomes degenerate. Further hyphal extension then occurs in the epidermis, killing more epidermal cells, and leading to collapse, but not penetration, of underlying tissue.


Author(s):  
John R. Rowley ◽  
John J. Skvarla

Observations of development in the nonaperaturate pollen of Canna generalis Bailey, based upon light and electron microscopy, indicate that the inner intine of this species is initiated by plasmalemmasomes originating at widely separated areas of the cell surface.The intine is that part of the pollen wall located between the sporopollenin exine and the cytoplasmic surface. It is often interbedded with the exine but is not itself composed of sporopollenin. In appearance and composition, the intine is comparable with the primary plant cell wall and has been characterized by Roland as an amorphous matrix of pectins with infrequent microfibrils.


1979 ◽  
Vol 27 (6) ◽  
pp. 1003-1010 ◽  
Author(s):  
D Menzel

Accumulation of peroxidase was demonstrated by light and electron microscopy to occur in Acetabularia in certain regions of the cap rays in relation to the development of the gametangia (cysts). Peroxidase was found to be incorporated into special, cell wall-like obstructions that separate the cap rays from the stalk when the secondary nuclei have settled in the cap rays. It is assumed that peroxidase acts as an anti-microbial protectant of the gametangia.


1973 ◽  
Vol 26 (6) ◽  
pp. 1231 ◽  
Author(s):  
TP O'brien ◽  
J Kuo ◽  
M E Mccully ◽  
S-Y Zee

The appearance of cells from the meristem of the root tip of Phaseolus vulgaris after fixation in a variety of coagulant and non-coagulant fixatives is described and illustrated by correlated light and electron microscopy. The action of these same fixatives and some of their components upon the living cells of the petiolar hairs of Heracleum mantegazzianum is then described. Glutaraldehyde emerged as an excellent fixative for general use from these studies and further tests show that it will stabilize Hecht's threads in plasmolysed onion epidermis against breakage during dehydration. However, the formation of rounded cytoplasmic vacuoles from a pre-existing set of canalicular vacuoles and transformations of the cell membrane and tonoplasts were noted during these studies and none of the fixatives tested prevent the formation of these artefacts.


1994 ◽  
Vol 72 (2) ◽  
pp. 182-188 ◽  
Author(s):  
E. Schmid ◽  
F. Oberwinkler

The host–fungus interaction between the achlorophyllous gametophyte of Botrychium lunaria and its fungal endophyte was studied by means of light and electron microscopy. Aseptate hyphae with a multilayered cell wall formed intracellular coils. The interface consisted of a thick layer of fibrillar matrix material, an electron-translucent zone, and the host plasmalemma. Several vesicles that show different stages of development and degeneration occurred within one host cell. Degenerating vesicles were encased by large amounts of an electron-translucent material. Arbuscules were not observed. The fungus did not infect the young sporophyte but degenerated within intact gametophyte cells. Key words: Botrychium lunaria, gametophyte, mycorrhiza, ultrastructure.


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