The effects of CO2 and membranes on sporulation in axenic cultures of flax rust

1985 ◽  
Vol 63 (8) ◽  
pp. 1418-1422 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Membrane Surface ◽  
Volatile Substances ◽  
Melampsora Lini ◽  
Paraffin Oil ◽  
Air Space ◽  
Saran Wrap ◽  
Axenic Cultures ◽  
Diffusion Of Gases

Uredospore production by axenically grown flax rust (Melampsora lini (Ehrenb.) Lev.) was measured as carotenoids (extinction units at 458 nm) per milligram protein. Sporulation was not affected by raising (flushing with 1–5% (v/v) CO2 in air) or lowering (KOH well in culture flasks) the level of CO2 in the air space above the cultures. Significant (two- to four-fold) increases in sporulation occurred beneath impermeable membranes of Parafilm or Saran wrap placed on the surface of young (3 weeks from seeding) mycelial mats for 2 weeks. The stimulatory effect was confined strictly to those areas of the mycelial mats in contact with the membranes. Both Parafilm and Saran wrap were easily and cleanly peeled away from the mycelial mats. Permeable Unipore and HVHP membranes, to which the fungus adhered strongly, did not stimulate sporulation. The fungus did not adhere to Unipore or HVHP membranes treated with silicone or paraffin oil; membranes thus treated stimulated sporulation. The stimulatory effect of membranes on sporulation appears to depend on the nature of the contact between the membrane surface and the mycelium and to be unrelated to the effect of the membranes on the diffusion of gases or other volatile substances.

Colony initiation in flax rust in axenic culture: involvement of a volatile factor

1979 ◽  
Vol 57 (23) ◽  
pp. 2657-2662 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Carbon Dioxide ◽  
Axenic Culture ◽  
Conclusive Evidence ◽  
Culture Flask ◽  
Melampsora Lini ◽  
Air Space ◽  
Lag Period ◽  
Axenic Cultures ◽  
Incubation Temperatures

In axenic cultures of flax rust (Melampsora lini) colonies are initiated after a lag period of 12–20 days, depending partly on incubation temperatures. Colony initiation is completely inhibited by removal of a volatile factor which is absorbed by KOH in the air space of the culture flask. The fungus remains sensitive to this inhibition for 8–10 days, i.e., until shortly before visible colonies would normally have developed. While in the presence of KOH, the fungus is not killed; cultures grow normally after removal of the KOH.Although conclusive evidence must await further work, the available data strongly suggest that carbon dioxide is responsible for this effect.

Axenic culture of flax rust isolated from cotyledons by cell-wall digestion

1972 ◽  
Vol 50 (12) ◽  
pp. 2601-2603 ◽  
Author(s):  
W. David Lane ◽  
Michael Shaw
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Cell Walls ◽  
Hydrolytic Enzymes ◽  
Axenic Culture ◽  
Rust Fungi ◽  
Host Cells ◽  
Melampsora Lini ◽  
Large Numbers ◽  
Axenic Cultures

A technique is described for the isolation of colonies of flax rust (Melampsora lini (Ehrenb.) Lév., Race No. 3) from infected cotyledons. The technique depends on the digestion of the host cell walls with hydrolytic enzymes and washing of the liberated colonies. It is thus possible to collect large numbers of flax-rust colonies with only a few host cells adhering to them. Axenic cultures were established from colonies isolated in this way. This technique may be useful in establishing axenic cultures of other rust fungi.

The fine structure of two rust fungi, Puccinia helianthi and Melampsora lini

1972 ◽  
Vol 50 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Michael D. Coffey ◽  
Barry A. Palevitz ◽  
Paul J. Allen
Keyword(s):  
Rust Fungus ◽  
Fungal Species ◽  
Wall Material ◽  
Fungus Infection ◽  
Puccinia Helianthi ◽  
Melampsora Lini ◽  
Cytoplasmic Microtubules ◽  
Axenic Cultures ◽  
Specialized Structure ◽  
Parasitic Phase

The parasitic phase of the uredial stage of rust fungus infection is characterized by the formation of a specialized structure—the haustorium. The haustorial neck contains a band of darkly staining wall material, the length of which is dependent on the fungal species. In older infected tissues a collar sometimes develops at the site of penetration. In such cells, the host plasmalemma appears to double back on itself between the collar and the haustorial neck. The mitochondria of the haustorium contain many plate-like cristae and, less frequently, concentric whorls of membranes. Cytoplasmic microtubules are also observed in both the neck and body of the haustorium. Centriolar plaques are found appressed to the nuclear envelopes in both the hyphae and haustoria. They frequently consist of two amorphous regions which are connected by a rod-shaped, layered structure. The septal pore of the intercellular hyphae contains a plug of electron-transparent material. Surrounding it is a matrix of dense amorphous cytoplasm devoid of organelles which is bordered by a hemispherical array of microbodies containing crystals. Axenic cultures of Melampsora lini mycelium were examined and found to contain similar septal pore regions. These cultures also show some differences from the parasitic hyphae. The septa-associated microbodies in these cells appear to derive from an aggregate of tubular endoplasmic reticulum cisternae. Their mitochondria differ from those of the intercellular hyphae in having more and longer, plate-like cristae and a denser staining matrix. They therefore represent a type intermediate between those of the intercellular hyphae and the haustoria. The pseudoparenchymatous stroma of the axenic cultures contains cells of widely divergent ages. Some are young as determined by their dense cytoplasmic contents and large lobed nuclei. However, others are older, with large vacuoles and many lipid bodies. In some cases they have thick cell walls consisting of many layers.

The effects of heat shock and inoculum density on growth and sporulation in axenic cultures of the flax rust fungus

1988 ◽  
Vol 66 (1) ◽  
pp. 189-193 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Heat Shock ◽  
Liquid Medium ◽  
Rust Fungus ◽  
Primary Factor ◽  
Melampsora Lini ◽  
Colony Number ◽  
Axenic Cultures ◽  
Axenic Conditions ◽  
Logarithmic Growth ◽  
Respective Number

The number of mycelial colonies of Melampsora lini (Ehrenb.) Lév. was increased by a 2-h heat shock at 31 °C delivered 3 h after uredospores were seeded on a liquid medium at 17 ± 0.5 °C under axenic conditions. At 35–38 days from seeding, the ratio of the respective number of colonies in shock and nonshock treatments in 125-mL culture flasks was highest (7.5 to 22) at inoculum levels (1 to 4 × 103 uredospores cm−2) that yielded about 10 colonies per flask without heat shock; the ratio declined sharply at inoculum levels adjusted to yield either smaller or larger numbers of colonies per flask without heat shock. Sporulation (extinction at 458 nm) and protein per colony were positively correlated; were not directly affected by heat shock; were determined by colony number; increased to maxima as mean colony number per flask increased from 1 or less to from 10 to 100 in different experiments; and decreased at higher colony numbers per flask. The results indicate that heat shock promotes the initiation of colonies; that colony number determines the duration of logarithmic growth; and that increasing competition among individual colonies is the primary factor limiting growth and sporulation, whether or not the uredospore germlings are subjected to heat shock.

Peroxidase Localization in Hartmanella Trophozoites

1971 ◽  
Vol 29 ◽  
pp. 346-347 ◽  
Author(s):  
George E. Childs ◽  
Joseph H. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrastructural Localization ◽  
Pathogenic Strain ◽  
Oxidative Enzymes ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Subject ◽  
Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

Role of spectrin in membrane fusion and in shape change of human erythrocyte ghost

1978 ◽  
Vol 36 (2) ◽  
pp. 328-329
Author(s):  
Hideo Hayashi ◽  
Yoshikazu Hirai ◽  
John T. Penniston
Keyword(s):  
Conformational Changes ◽  
Human Erythrocyte ◽  
Shape Change ◽  
Membrane Surface ◽  
Slight Modification ◽  
Active Role ◽  
Main Role ◽  
Bank Blood ◽  
Human Erythrocyte Ghost

Spectrin is a membrane associated protein most of which properties have been tentatively elucidated. A main role of the protein has been assumed to give a supporting structure to inside of the membrane. As reported previously, however, the isolated spectrin molecule underwent self assemble to form such as fibrous, meshwork, dispersed or aggregated arrangements depending upon the buffer suspended and was suggested to play an active role in the membrane conformational changes. In this study, the role of spectrin and actin was examined in terms of the molecular arrangements on the erythrocyte membrane surface with correlation to the functional states of the ghosts.Human erythrocyte ghosts were prepared from either freshly drawn or stocked bank blood by the method of Dodge et al with a slight modification as described before. Anti-spectrin antibody was raised against rabbit by injection of purified spectrin and partially purified.

Role of PKC isozymes in water transport in toad urinary bladder

1991 ◽  
Vol 49 ◽  
pp. 302-303
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Apical Membrane ◽  
Membrane Surface ◽  
Protein A ◽  
Cell Types ◽  
Leukemic Cells ◽  
Toad Urinary Bladder ◽  
Pkc Isozymes ◽  
Antibody Labeling

Protein kinase C (PKC) isozymes, when activated, are translocated to particulate membrane fractions for transport to the apical membrane surface in a variety of cell types. Evidence of PKC translocation was demonstrated in human megakaryoblastic leukemic cells, and in cardiac myocytes and fibroblasts, using FTTC immunofluorescent antibody labeling techniques. Recently, we reported immunogold localizations of PKC subtypes I and II in toad urinary bladder epithelia, following 60 min stimulation with Mezerein (MZ), a PKC activator, or antidiuretic hormone (ADH). Localization of isozyme subtypes I and n was carried out in separate grids using specific monoclonal antibodies with subsequent labeling with 20nm protein A-gold probes. Each PKC subtype was found to be distributed singularly and in discrete isolated patches in the cytosol as well as in the apical membrane domains. To determine if the PKC isozymes co-localized within the cell, a double immunogold labeling technique using single grids was utilized.

SEM/FESEM imaging of lamellar structures in melt extruded polyethylene films

1992 ◽  
Vol 50 (2) ◽  
pp. 1142-1143
Author(s):  
R.T. Chen ◽  
M.G. Jamieson ◽  
R. Callahan
Keyword(s):  
Imaging Techniques ◽  
Membrane Surface ◽  
High Stress ◽  
Extrusion Direction ◽  
Polymeric Membranes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystalline Polymers ◽  
Lamellar Structures ◽  
Resolution Imaging

“Row lamellar” structures have previously been observed when highly crystalline polymers are melt-extruded and recrystallized under high stress. With annealing to perfect the stacked lamellar superstructure and subsequent stretching in the machine (extrusion) direction, slit-like micropores form between the stacked lamellae. This process has been adopted to produce polymeric membranes on a commercial scale with controlled microporous structures. In order to produce the desired pore morphology, row lamellar structures must be established in the membrane precursors, i.e., as-extruded and annealed polymer films or hollow fibers. Due to the lack of pronounced surface topography, the lamellar structures have typically been investigated by replica-TEM, an indirect and time consuming procedure. Recently, with the availability of high resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission scanning electron microscopy (FESEM), the microporous structures on the membrane surface as well as lamellar structures in the precursors can be directly examined.The materials investigated are Celgard® polyethylene (PE) flat sheet membranes and their film precursors, both as-extruded and annealed, made at different extrusion rates (E.R.).

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

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