Alternaria toxins and their effects on host plants

1995 ◽  
Vol 73 (S1) ◽  
pp. 453-458 ◽  
Author(s):  
Hiroshi Otani ◽  
Keisuke Kohmoto ◽  
Motoichiro Kodama
Keyword(s):  
Plasma Membrane ◽  
Host Plants ◽  
Plasma Membranes ◽  
Early Effect ◽  
The Third ◽  
The Matrix ◽  
Electrolyte Loss ◽  
Host Specific Toxins ◽  
Acid Structure ◽  
Malate Oxidation

There are now nine or more Alternaria pathogens that produce host-specific toxins, and the structures of most of the toxins have been elucidated. Alternaria host-specific toxins are classified in three groups in terms of the primary site action. ACT-, AF-, and AK-toxins have in common an epoxy-decatrienoic acid structure and exert their primary effect on the plasma membrane of susceptible cells. A rapid increase in electrolyte loss from tissues and invaginations in the plasma membranes are common effects of these toxins. The second group is represented by ACR(L)-toxin, which induces changes in mitochondria, including swelling, vesiculation of cristae, decrease in the electron density of the matrix, increase in the rate of NADH oxidation, and inhibition of malate oxidation. The third group consists of AM-toxin, which appears to exert an early effect on both chloroplasts and plasma membranes. AM-toxin induces vesiculation of grana lamellae, inhibition of CO2 fixation, invagination of plasma membranes, and electrolyte loss. The roles of host-specific toxins in pathogenesis are discussed. Key words: Alternaria, host-specific toxin, plasma membrane, mitochondrion, chloroplast.

scholarly journals Agorins: major structural proteins of the plasma membrane skeleton of P815 tumor cells.

1986 ◽  
Vol 103 (2) ◽  
pp. 351-360 ◽  
Author(s):  
J R Apgar ◽  
M F Mescher
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Matrix Protein ◽  
Membrane Skeleton ◽  
Insoluble Fraction ◽  
Molecular Weights ◽  
Cell Plasma ◽  
The Matrix ◽  
Section Electron ◽  
Mastocytoma Cells

Plasma membranes of P815 mastocytoma cells contain a set of proteins that remain selectively insoluble upon extraction of the membranes with Triton X-100, and appear to form a membrane skeletal matrix independent of the filamentous cytoskeletal systems. EGTA treatment of the matrix was found to release approximately 25% of the protein as polypeptides of 70, 69, 38, and 36 kD, all of which appear to be peripheral components associated with the cytoplasmic face of the plasma membrane via divalent cation-dependent interactions. About 75% of the total matrix protein was recovered in the EGTA-insoluble fraction. Actin accounted for approximately 5% of the total protein in the EGTA-insoluble fraction. The rest was accounted for by two novel proteins of 20 and 40 kD which, despite their relatively low molecular weights, do not enter SDS PAGE gels. Together these proteins account for approximately 15% of the total plasma membrane protein, and are thus present in much higher amounts than any other characterized protein of nucleated cell plasma membranes. Based on the extensive associations of these proteins to form very large detergent-insoluble structures, we propose that they may be named agorin I, the 20-kD protein, and agorin II, the 40-kD protein, from the Greek agora meaning assembly. The amount and properties of these proteins and the appearance of the EGTA-insoluble material in thin-section electron micrographs indicate that the agorins are the major structural elements of the membrane matrix, and thus of the putative membrane skeleton.

scholarly journals Alpha-granule pool of glycoprotein IIb-IIIa in normal and pathologic platelets and megakaryocytes

Blood ◽  
1990 ◽  
Vol 75 (6) ◽  
pp. 1220-1227 ◽  
Author(s):  
EM Cramer ◽  
GF Savidge ◽  
W Vainchenker ◽  
MC Berndt ◽  
D Pidard ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Polyclonal Antibodies ◽  
Staining Technique ◽  
Membrane System ◽  
Type I ◽  
Immunogold Staining ◽  
The Third ◽  
Granule Membrane ◽  
Gray Platelet Syndrome

Abstract Using an immunogold staining technique and electron microscopy, we investigated the localization of the alpha-granule pool of glycoprotein (GP) IIb-IIIa in normal platelets and maturing megakaryocytes (MK), in pathologic platelets from a patient with type I Glanzmann's thrombasthenia (GT), and from three patients with the gray platelet syndrome (GPS). In normal resting platelets, GPIIb-IIIa was observed on the plasmatic side of the plasma membrane, the open canicular system (OCS) membranes, and along the internal face of the alpha-granule membrane. This location was found with three monospecific polyclonal antibodies: one anti-GPIIb-IIIa antibody, the second specific for GPIIb, and the third specific for GPIIIa. After thrombin stimulation, the alpha-granule labeling disappeared whereas membrane labeling increased. Platelets from GT did not display labeling on plasma membranes, OCS membranes, or alpha-granule membranes. Platelets from the three patients with GPS displayed intense labeling of the plasma membrane and the OCS membrane, as well as the abnormal small alpha- granules and along the inside of large vacuoles (which contain the granule membrane protein [GMP]-140). In cultured immature MK from normal progenitors, both peptide components of GPIIb-IIIa appeared in the Golgi saccules and vesicles, and in the small precursors of alpha- granules, labeling both their membranes and their matrix. It was then observed only on the membrane of the mature MK alpha-granules, although labeling was less consistent than on the platelet granules. The MK plasma membrane and demarcation membrane system also displayed GPIIb- IIIa labeling. In conclusion, this study demonstrates that GPIIb-IIIa is present on the internal face of the alpha-granule membranes of platelets (where it appears early during MK maturation) as well as in the abnormal alpha-granules of gray platelets; it is absent from GT type I platelets.

scholarly journals Purification and Biological Characterization of Host-Specific SV-Toxins from Stemphylium vesicarium Causing Brown Spot of European Pear

1999 ◽  
Vol 89 (10) ◽  
pp. 947-953 ◽  
Author(s):  
P. Singh ◽  
R. Bugiani ◽  
P. Cavanni ◽  
H. Nakajima ◽  
M. Kodama ◽  
...  
Keyword(s):  
Brown Spot ◽  
Early Effect ◽  
Stemphylium Vesicarium ◽  
European Pear ◽  
Veinal Necrosis ◽  
Resistant Cultivars ◽  
Culture Filtrates ◽  
Leaf Tissues ◽  
Electrolyte Loss ◽  
Host Specific Toxins

Culture filtrates of a pathogenic isolate (IT37) of Stemphylium vesicarium, causing brown spot of European pear, induced veinal necrosis only on pear leaves susceptible to the pathogen. Two host-specific toxins, SV-toxins I and II, were purified from culture filtrates of IT37 by successively using Amberlite XAD-2 resin adsorption, cellulose thin-layer chromatography, and high-performance liquid chromatography under three different sets of conditions. Susceptible cultivars showed veinal necrosis at a SV-toxin I concentration of 0.01 to 0.1 μg/ml, whereas resistant cultivars were insensitive to the toxin at 1,000 μg/ml. SV-toxins I and II caused a dose-dependent increase in electrolyte loss from susceptible leaf tissues. No increase in electrolyte loss was detected in leaf tissues from resistant cultivars. The results of physiological studies indicated that SV-toxins appear to have an early effect on plasma membranes of susceptible leaves. Spores of a nonpathogenic isolate induced necrotic lesions on susceptible leaves in the presence of a small amount of toxin. SV-toxins were detected in intercellular fluids obtained from diseased leaves after inoculation with the pathogen. The results indicate that SV-toxins I and II produced by S. vesicarium can be characterized as host-specific toxins.

scholarly journals Alpha-granule pool of glycoprotein IIb-IIIa in normal and pathologic platelets and megakaryocytes

Blood ◽  
1990 ◽  
Vol 75 (6) ◽  
pp. 1220-1227 ◽  
Author(s):  
EM Cramer ◽  
GF Savidge ◽  
W Vainchenker ◽  
MC Berndt ◽  
D Pidard ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Polyclonal Antibodies ◽  
Staining Technique ◽  
Membrane System ◽  
Type I ◽  
Immunogold Staining ◽  
The Third ◽  
Granule Membrane ◽  
Gray Platelet Syndrome

Using an immunogold staining technique and electron microscopy, we investigated the localization of the alpha-granule pool of glycoprotein (GP) IIb-IIIa in normal platelets and maturing megakaryocytes (MK), in pathologic platelets from a patient with type I Glanzmann's thrombasthenia (GT), and from three patients with the gray platelet syndrome (GPS). In normal resting platelets, GPIIb-IIIa was observed on the plasmatic side of the plasma membrane, the open canicular system (OCS) membranes, and along the internal face of the alpha-granule membrane. This location was found with three monospecific polyclonal antibodies: one anti-GPIIb-IIIa antibody, the second specific for GPIIb, and the third specific for GPIIIa. After thrombin stimulation, the alpha-granule labeling disappeared whereas membrane labeling increased. Platelets from GT did not display labeling on plasma membranes, OCS membranes, or alpha-granule membranes. Platelets from the three patients with GPS displayed intense labeling of the plasma membrane and the OCS membrane, as well as the abnormal small alpha- granules and along the inside of large vacuoles (which contain the granule membrane protein [GMP]-140). In cultured immature MK from normal progenitors, both peptide components of GPIIb-IIIa appeared in the Golgi saccules and vesicles, and in the small precursors of alpha- granules, labeling both their membranes and their matrix. It was then observed only on the membrane of the mature MK alpha-granules, although labeling was less consistent than on the platelet granules. The MK plasma membrane and demarcation membrane system also displayed GPIIb- IIIa labeling. In conclusion, this study demonstrates that GPIIb-IIIa is present on the internal face of the alpha-granule membranes of platelets (where it appears early during MK maturation) as well as in the abnormal alpha-granules of gray platelets; it is absent from GT type I platelets.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

Pore-Spanning Plasma Membranes Derived from Giant Plasma Membrane Vesicles

2021 ◽  
Author(s):  
Nikolas K. Teiwes ◽  
Ingo Mey ◽  
Phila C. Baumann ◽  
Lena Strieker ◽  
Ulla Unkelbach ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles

scholarly journals Resolution of diaminobenzidine for the detection of horseradish peroxidase on surfaces of cultured cells.

1985 ◽  
Vol 33 (8) ◽  
pp. 837-839 ◽  
Author(s):  
A Messing ◽  
A Stieber ◽  
N K Gonatas
Keyword(s):  
Plasma Membrane ◽  
Horseradish Peroxidase ◽  
Plasma Membranes ◽  
Cultured Cells ◽  
Lateral Spread ◽  
Ciliary Ganglion ◽  
Monolayer Cultures ◽  
Indirect Immunoperoxidase ◽  
Ciliary Ganglion Neurons ◽  
Ganglion Neurons

The resolution of indirect immunoperoxidase methods for localizing antigens on the surface of plasma membranes of cultured cells was tested using dissociated monolayer cultures of ciliary ganglion neurons prelabeled with cationic ferritin. Clusters of ferritin were produced on the cell surface by warming the cells to 37 degrees C after the ferritin, rabbit anti-ferritin, and goat anti-rabbit immunoglobulin coupled to horseradish peroxidase had all been applied. Intense 3,3'-diaminobenzidine tetrahydrochloride (DAB) staining was limited to the regions immediately surrounding the ferritin clusters. The lateral spread of the DAB reaction product beyond the outer ferritin particles in each cluster averaged 54-81 nm in four experiments. A second type of increased density, coinciding with the thickness of the plasma membrane, was also seen. These stained plasma membranes extended 161-339 nm from the ferritin clusters.

scholarly journals Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets

1986 ◽  
Vol 239 (2) ◽  
pp. 301-310 ◽  
Author(s):  
W D Sweet ◽  
F Schroeder
Keyword(s):  
Plasma Membrane ◽  
Active Site ◽  
Plasma Membranes ◽  
Local Anaesthetics ◽  
Cationic Drugs ◽  
Cell Plasma ◽  
Composition And Structure ◽  
Highly Sensitive ◽  
Functional Consequences ◽  
Anionic Drugs

The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5′-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

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