Ontogeny of Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae. II. Transmission electron microscopy

1987 ◽  
Vol 65 (9) ◽  
pp. 1940-1947 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
A. E. Ashford
Keyword(s):  
Cortical Layer ◽  
Epidermal Cells ◽  
Root Cap ◽  
Pisolithus Tinctorius ◽  
Dense Layer ◽  
Hartig Net ◽  
Transmission Electron ◽  
Fungal Hyphae ◽  
Cytoplasmic Content ◽  
Eucalyptus Pilularis

Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae were synthesized in growth pouches, and ultrastructural features of the two symbionts were documented during ontogeny. In the root cap – meristem zone, fungal hyphae envelop the root cap and penetrate between root cap cells. These fungal hyphae have numerous organelles and nuclei, some of which are in mitosis. The inner mantle hyphae in this zone and in the pre-Hartig net zone are heterogeneous in cytoplasmic content and are separated from the epidermis by an electron-dense layer. In the young Hartig net zone, hyphae penetrate between epidermal cells which contain electron-dense vacuolar deposits. In this zone and in the older Hartig net zone, hyphae do not penetrate beyond the epidermis and therefore a paraepidermal Hartig net is formed. The outer cortical layer develops as a hypodermis with suberized cell walls. The root–fungus interface consists of Hartig net hyphae which form a labyrinthine wall system and epidermal cells which are enlarged radially and contain electron-dense vacuolar deposits.

Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. II. Transmission electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 201-210 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Electron Microscopy ◽  
Epidermal Cells ◽  
Root Cap ◽  
Alnus Rubra ◽  
Golgi Bodies ◽  
Hartig Net ◽  
Transmission Electron ◽  
Meristem Zone ◽  
Basal Portion ◽  
Branching System

Ultrastructural features of the two symbionts in ectomycorrhizae formed between Alnus rubra and Alpova diplophloeus change with developmental stage. In the root cap – meristem zone, hyphae penetrate between vacuolated root cap cells and become appressed to epidermal cells containing small vacuoles, plastids with starch, numerous Golgi bodies, mitochondria, and endoplasmic reticulum cisternae. In the young Hartig net zone, hyphae with few vacuoles penetrate between vacuolated epidermal cells that still contain numerous Golgi bodies but now have plastids with small starch grains. Hartig net hyphae begin to branch and eventually form a complex branching system in the mature Hartig net zone. Hartig net hyphae in the basal portion of the ectomycorrhizae synthesize lipid and finally become vacuolated.

Structure and ontogeny of Alnus crispa – Alpova diplophloeus ectomycorrhizae

1986 ◽  
Vol 64 (1) ◽  
pp. 177-192 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
Y. Piché
Keyword(s):  
Structural Changes ◽  
Hyphal Growth ◽  
Root Surface ◽  
Epidermal Cells ◽  
Transfer Cells ◽  
Wall Ingrowths ◽  
Alnus Crispa ◽  
Hartig Net ◽  
Fungal Hyphae ◽  
Branching System

Alnus crispa (Ait.) Pursh seedlings were grown in plastic pouches and inoculated with Frankia to induce nodules and subsequently with Alpova diplophloeus (Zeller & Dodge) Trappe & Smith to form ectomycorrhizae. The earliest events in ectomycorrhiza formation involved contact of the root surface by hyphae, hyphal proliferation to form a thin mantle, and further hyphal growth to form a thick mantle. Structural changes in the host, the mycosymbiont, and the fungus–epidermis interface were described at various stages in the ontogeny of ectomycorrhizae. Fungal hyphae in contact with epidermal cells in the regions of intercellular penetration and paraepidermal Hartig net developed numerous rough endoplastic reticulum cisternae. In more proximal regions of the mycorrhiza, these gradually became fewer in number and smooth. A complicated labyrinthine wall branching system also developed in the fungus in these regions. Concurrently, epidermal cells formed wall ingrowths in regions adjacent to Hartig net hyphae. There was a gradient in the formation of these epidermal transfer cells as the mycorrhiza developed, and an additional deposition of secondary cell wall over the wall ingrowths occurred as transfer cells senesced. Nonmycorrhizal control roots did not develop epidermal wall ingrowths. Electron-dense material, which was also autofluorescent, was deposited in the outer tangential walls of the exodermis contiguous to the paraepidermal Hartig net.

Ectomycorrhiza synthesis between isolated roots of Eucalyptus pilularis and Pisolithus tinctorius

1988 ◽  
Vol 66 (6) ◽  
pp. 1237-1239 ◽  
Author(s):  
S. R. Bailey ◽  
R. L. Peterson
Keyword(s):  
Filter Paper ◽  
Callus Cultures ◽  
Pisolithus Tinctorius ◽  
Root Tips ◽  
Apical Portion ◽  
Hypocotyl Explants ◽  
Hartig Net ◽  
Isolated Roots ◽  
Basal Portion ◽  
Eucalyptus Pilularis

Callus cultures were established from epicotyl–hypocotyl explants of Eucalyptus pilularis seedlings. Roots formed on these cultures were excised and placed in divided petri plates. The apical portion of each root was placed on filter paper overlying modified Bonner–Deverian medium, while the basal portion was placed on Bonner–Deverian medium containing carbohydrates. Plugs of Pisolithus tinctorius mycelium were placed adjacent to the apical portion of each root. After 10–14 days, approximately 40% of all root tips formed a mantle and Hartig net typical of ectomycorrhizas.

Ontogeny of Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae. I. Light microscopy and scanning electron microscopy

1987 ◽  
Vol 65 (9) ◽  
pp. 1927-1939 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
A. E. Ashford
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Ectomycorrhizal Fungus ◽  
Pisolithus Tinctorius ◽  
Broad Host Range ◽  
Lateral Root Development ◽  
First Order ◽  
Hartig Net ◽  
Ectomycorrhizal Roots ◽  
Eucalyptus Pilularis

Eucalyptus pilularis Sm. seedlings were grown in growth pouches and inoculated with the broad host range ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker & Couch. External morphology and internal structure of all stages of ectomycorrhiza formation on first-order and second-order laterals were studied. The morphology of the ectomycorrhiza is dependent on the stage of lateral root development at the time of colonization by fungal hyphae. Emerging lateral roots are colonized by hyphae originating from the inner mantle of the parent root. The Hartig net does not spread internally from the parent root to the lateral root. All primary tissues of mycorrhizal lateral roots are differentiated close to the apical meristem. The epidermal cells undergo a marked increased in radial growth instead of the usual elongation in the axial plane. The hypodermis is a barrier to the penetration of hyphae so that Hartig net formation is paradermal only. Older portions of ectomycorrhizal roots show a degeneration of the epidermis, hypodermis, and cortex excluding the endodermis, and a proliferation of hyphae in these senescing tissues.

Structure and ontogeny of Betula alleghaniensis – Pisolithus tinctorius ectomycorrhizae

1990 ◽  
Vol 68 (3) ◽  
pp. 579-593 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
L. H. Melville
Keyword(s):  
Root Hairs ◽  
Root Surface ◽  
Pisolithus Tinctorius ◽  
Initial Contact ◽  
Broad Host Range ◽  
Betula Alleghaniensis ◽  
Cortical Cells ◽  
Structural Modifications ◽  
Hartig Net ◽  
Primary Roots

The ontogeny and ultrastructure of ectomycorrhizae synthesized between Betula alleghaniensis (yellow birch) and Pisolithus tinctorius, a broad host range fungus, were studied to determine the structural modifications in both symbionts during ectomycorrhiza establishment. A number of stages, including initial contact of hyphae with the root surface, early mantle formation, and mature mantle formation, were distinguished. Interactions between hyphae and root hairs were frequent. As a paraepidermal Hartig net developed, root epidermal cells elongated in a radial direction, but wall ingrowths were not formed. Repeated branching of Hartig net hyphae resulted in extensive fine branches and the compartmentalization of hyphal cytoplasm. Nuclei and elongated mitochondria were frequently located in the narrow cytoplasmic compartments, and [Formula: see text] thickenings developed along walls of cortical cells in primary roots.

scholarly journals A novel exosome biogenesis mechanism: multivesicular structures budding and rupturing at the plasma membrane

2019 ◽  
Author(s):  
Stephanie Leon Quinonez ◽  
Ian R. Brown ◽  
Helen E. Grimsley ◽  
Jindrich Cinatl ◽  
Martin Michaelis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Membrane Association ◽  
Dense Layer ◽  
Physiological Processes ◽  
Exosome Biogenesis ◽  
Transmission Electron ◽  
Typical Morphology ◽  
Intercellular Signalling ◽  
Microscopy Images

AbstractExosomes are small vesicles secreted by the cells, which mediate intercellular signalling and systemic physiological processes. Exosomes are known to originate from the intraluminal vesicles of the multivesicular endosome that fuses with the plasma membrane. We found that the non-small cell lung cancer (NSCLC) cell lines, HCC15 and A549, secreted exosomes with typical morphology and protein contents. Unexpectedly, transmission electron microscopy images indicated that the cells formed multivesicular structures that protruded from the plasma membrane and ruptured to release the exosomes. There were smooth multivesicular structures surrounded by an ordinary looking membrane, multivesicular structures coated by an electron dense layer with regular spacing pattern, and intermediate forms that combined elements of both. Electron microscopy images suggested that exosomes are release from these structures by burst events and not by the conventional fusion process. The molecular details of this novel mechanism for membrane association, deformation and fusion is to be unveiled in the future.

scholarly journals A Novel Class of Ectomycorrhiza-Regulated Cell Wall Polypeptides in Pisolithus tinctorius

1999 ◽  
Vol 12 (10) ◽  
pp. 862-871 ◽  
Author(s):  
Pascal Laurent ◽  
Catherine Voiblet ◽  
Denis Tagu ◽  
Dulcinéia de Carvalho ◽  
Uwe Nehls ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Adhesion ◽  
Polyacrylamide Gel Electrophoresis ◽  
State Level ◽  
Root Surface ◽  
Pisolithus Tinctorius ◽  
Surface Proteins ◽  
Ectomycorrhizal Symbiosis ◽  
Fungal Cell ◽  
Fungal Hyphae

Development of the ectomycorrhizal symbiosis leads to the aggregation of fungal hyphae to form the mantle. To identify cell surface proteins involved in this developmental step, changes in the biosynthesis of fungal cell wall proteins were examined in Eucalyptus globulus-Pisolithus tinctorius ectomycorrhizas by two-dimensional polyacrylamide gel electrophoresis. Enhanced synthesis of several immunologically related fungal 31- and 32-kDa polypeptides, so-called symbiosis-regulated acidic polypeptides (SRAPs), was observed. Peptide sequences of SRAP32d were obtained after trypsin digestion. These peptides were found in the predicted sequence of six closely related fungal cDNAs coding for ectomycorrhiza up-regulated transcripts. The PtSRAP32 cDNAs represented about 10% of the differentially expressed cDNAs in ectomycorrhiza and are predicted to encode alanine-rich proteins of 28.2 kDa. There are no sequence homologies between SRAPs and previously identified proteins, but they contain the Arg-Gly-Asp (RGD) motif found in cell-adhesion proteins. SRAPs were observed on the hyphal surface by immunoelectron microscopy. They were also found in the host cell wall when P. tinctorius attached to the root surface. RNA blot analysis showed that the steady-state level of PtSRAP32 transcripts exhibited a drastic up-regulation when fungal hyphae form the mantle. These results suggest that SRAPs may form part of a cell-cell adhesion system needed for aggregation of hyphae in ectomycorrhizas.

Influence of Carvacrol and 1,8-Cineole on Cell Viability, Membrane Integrity, and Morphology of Aeromonas hydrophila Cultivated in a Vegetable-Based Broth

2015 ◽  
Vol 78 (2) ◽  
pp. 424-429 ◽  
Author(s):  
JOSSANA PEREIRA de SOUSA ◽  
KATARYNE ÁRABE RIMÁ de OLIVEIRA ◽  
REGINA CELIA BRESSAN QUEIROZ de FIGUEIREDO ◽  
EVANDRO LEITE de SOUZA
Keyword(s):  
Cell Viability ◽  
Membrane Permeability ◽  
Aeromonas Hydrophila ◽  
Membrane Integrity ◽  
Cell Membrane Permeability ◽  
Confocal Laser ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Transmission Electron ◽  
Cytoplasmic Content

This study investigated the effects of carvacrol (CAR) and 1,8-cineole (CIN) alone (at the MIC) or in combination at subinhibitory amounts (both at 1/8 MIC) on the cell viability, membrane permeability, and morphology of Aeromonas hydrophila INCQS 7966 (A. hydrophila) cultivated in a vegetable-based broth. CAR and CIN alone or in combination severely affected the viability of the bacteria and caused dramatic changes in the cell membrane permeability, leading to cell death, as observed by confocal laser microscopy. Scanning and transmission electron microscopy images of bacterial cells exposed to CAR or CIN or the mixture of both compounds revealed severe changes in cell wall structure, rupture of the plasma membrane, shrinking of cells, condensation of cytoplasmic content, leakage of intracellular material, and cell collapse. These findings suggest that CAR and CIN alone or in combination at subinhibitory amounts could be applied to inhibit the growth of A. hydrophila in foods, particularly as sanitizing agents in vegetables.

Root gravitropism requires lateral root cap and epidermal cells for transport and response to a mobile auxin signal

2005 ◽  
Vol 7 (11) ◽  
pp. 1057-1065 ◽  
Author(s):  
Ranjan Swarup ◽  
Eric M. Kramer ◽  
Paula Perry ◽  
Kirsten Knox ◽  
H. M. Ottoline Leyser ◽  
...  
Keyword(s):  
Lateral Root ◽  
Epidermal Cells ◽  
Root Cap ◽  
Root Gravitropism

Synergistic effect of cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork

2019 ◽  
Vol 26 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Yuexia Wang ◽  
Xiaoyan Li ◽  
Yangliu Lu ◽  
Jianan Wang ◽  
Biao Suo
Keyword(s):  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Meat Product ◽  
Membrane Integrity ◽  
Weibull Model ◽  
Mathematical Tool ◽  
Membrane Rupture ◽  
Transmission Electron ◽  
Ground Pork ◽  
Cytoplasmic Content

The aim of this study was to statistically evaluate the effect of a naturally food-derived cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork. This study combined four concentrations of cinnamaldehyde (0, 0.1, 0.5, and 1.0% vol/wt) and four temperatures (55, 60, 65, and 70 ℃) to predict the thermal inactivation curves of L. monocytogenes. The Weibull model successfully described the primary thermal inactivation using the Integrated Pathogen Modeling Program. These results statistically proposed that the cinnamaldehyde supplementation in ground pork attenuates the thermo-tolerance of L. monocytogenes. The time for achieving a 5-log10 reduction of L. monocytogenes declined from 28.14 to 17.35 min at 55 ℃ when the ground pork sample was supplemented by 1% cinnamaldehyde, while the time declined from 1.95 to 0.34 min at 70 ℃. Thereafter, based on the 5.0-log10 lethality, secondary models were fitted by a selected polynomial model. The transmission electron microscopy revealed that cinnamaldehyde causes serious damage to membrane integrity and increases the occurrence of cell membrane rupture and leakage of cytoplasmic content under thermal treatment. Our model represents a mathematical tool that will help meat-product manufacturers to improve the efficacy of thermal processing ground pork supplemented with cinnamaldehyde.

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